JP2020055147A - Method for manufacturing polyimide film and method for manufacturing metal-clad laminated plate - Google Patents

Abstract

To improve adhesion between polyimide layers without needing a special step such as surface treatment in manufacture of a polyimide film having a plurality of polyimide layers or a metal-clad laminated plate.SOLUTION: A method for manufacturing a polyimide film including a first polyimide layer (A) and a second polyimide layer (B) stacked on at least one surface of the first polyimide layer (A) includes I) a step of preparing the first polyimide layer (A) containing polyimide having a ketone group, II) a step of stacking a resin layer containing a polyamic acid (b) having a functional group having a mutual action with the ketone group, on the first polyimide layer (A) and III) a step of heat-treating the resin layer containing the polyamic acid (b) along with the first polyimide layer (A), imidizing the polyamic acid (b) and forming the second polyimide layer (B).SELECTED DRAWING: None

Description

  The present invention relates to a method for producing a polyimide film and a metal-clad laminate that can be used as materials for circuit boards and the like.

  2. Description of the Related Art In recent years, with the progress of miniaturization, weight reduction, and space saving of electronic devices, a flexible printed circuit (FPC) that is thin and lightweight, has flexibility, and has excellent durability even when repeatedly bent. ) Demand is increasing. Since FPCs can be mounted three-dimensionally and at high density even in limited space, their applications are expanding, for example, to wiring of electronic devices such as HDDs, DVDs, mobile phones, and smartphones, and to components such as cables and connectors. I am doing it. As an insulating resin used for the FPC, polyimide having excellent heat resistance and adhesiveness has attracted attention.

  As a method of manufacturing a polyimide film as an FPC material or a metal-clad laminate having a polyimide insulating layer, a polyimide precursor layer is formed by applying a resin solution of polyamic acid, and then a polyimide layer is formed by imidization. Methods are known (for example, Patent Documents 1 and 2).

  When manufacturing a polyimide film or a metal-clad laminate having a plurality of polyimide layers by a casting method, generally, on a substrate such as a copper foil, after sequentially forming a plurality of polyimide precursor layers, these Are collectively imidized. However, when a plurality of polyimide precursor layers are simultaneously imidized, the solvent and imidized water in the polyimide precursor layer are not completely removed, and foaming and peeling between the polyimide layers are caused by the residual solvent and the imidized water, thereby increasing the yield. There is a problem that it causes a decrease in

  The problems of foaming and peeling can be solved by repeatedly imidizing the polyimide precursor layer one by one and applying a polyamic acid resin liquid thereon. However, if a resin solution of polyamic acid is further applied on the polyimide layer once imidized and imidized, it is difficult to sufficiently obtain adhesion between the layers. In the prior art, a proposal has been made to improve the adhesion between layers by applying a surface treatment such as a corona treatment or a plasma treatment to the surface of an underlying polyimide film or polyimide layer before applying a resin solution of polyamic acid. (For example, Patent Documents 3 and 4).

International Publication WO2016 / 159104 JP 2004-322441 A JP 2010-116443 A JP 2012-134478 A

  In the method of performing surface treatment on imidized polyimide in order to obtain interlayer adhesion as in Patent Documents 3 and 4, equipment for the surface treatment is required, and the number of steps is increased to increase the manufacturing throughput. Is reduced.

  Therefore, an object of the present invention is to improve the adhesion between polyimide layers without the need for a special step such as surface treatment in the production of a polyimide film or a metal-clad laminate having a plurality of polyimide layers. .

  The present inventors require a special process such as surface treatment by utilizing the interaction between the resin component of the polyimide precursor layer formed by the casting method and the resin component of the polyimide layer to be the base. It has been found that the adhesion between the polyimide layers can be improved without using the same, and the present invention has been completed.

That is, the method for producing a polyimide film of the present invention comprises a first polyimide layer (A), a second polyimide layer (B) laminated on at least one surface of the first polyimide layer (A), This is a method for producing a polyimide film comprising:
The method for producing a polyimide film of the present invention comprises the following steps I to III;
I) a step of preparing a first polyimide layer (A) containing a polyimide having a ketone group;
II) laminating a resin layer containing a polyamic acid (b) having a functional group having a property of interacting with the ketone group on the first polyimide layer (A);
III) a step of heat-treating the resin layer containing the polyamic acid (b) together with the first polyimide layer (A) to imidize the polyamic acid (b) to form a second polyimide layer (B);
Is included.

  In the method for producing a polyimide film according to the present invention, the polyimide constituting the first polyimide layer (A) includes a tetracarboxylic acid residue (1a) and a diamine residue (2a); The ketone group may be 5 mole parts or more based on 100 mole parts in total of the acid residue (1a) and the diamine residue (2a).

  In the method for producing a polyimide film of the present invention, the resin layer containing the polyamic acid (b) includes a tetracarboxylic acid residue (1b) and a diamine residue (2b), and the diamine residue (2b ) The tetracarboxylic acid residue (1b) may be less than 1 mol per 1 mol.

  In the method for producing a polyimide film according to the present invention, the first polyimide layer (A) is formed by laminating a resin layer containing a polyamic acid (a) having a ketone group on a base material, and the polyamic acid together with the base material is provided. It may be formed by imidizing (a).

The method for producing a metal-clad laminate according to the present invention comprises a metal layer, a first polyimide layer (A), and a second polyimide layer (B) laminated on one surface of the first polyimide layer (A). ), And a method for producing a metal-clad laminate.
The method for producing a metal-clad laminate of the present invention comprises the following steps i to iv:
i) a step of forming at least one or more polyamic acid resin layers having a resin layer containing a polyamic acid (a) having a ketone group on the surface layer on the metal layer;
ii) heat treating the polyamic acid resin layer together with the metal layer to imidize the polyamic acid, thereby forming a first polyimide layer (A) containing a polyimide having a ketone group on the metal layer; Step of forming an intermediate in which a polyimide layer having a part is laminated,
iii) laminating a resin layer containing a polyamic acid (b) having a functional group having a property of interacting with the ketone group on the first polyimide layer (A);
iv) heat treating the resin layer of the polyamic acid (b) together with the intermediate, and imidizing the polyamic acid (b) to form a second polyimide layer (B);
Is included.

  The method of manufacturing a circuit board according to the present invention includes a step of processing a wiring circuit of the metal layer of the metal-clad laminate manufactured by the above method.

  According to the method of the present invention, a polyimide film or a metal-clad laminate having excellent adhesion between polyimide layers can be produced without impairing the throughput.

  Hereinafter, embodiments of the present invention will be described.

[First Embodiment: Method for Producing Polyimide Film]
The method for manufacturing a polyimide film according to the present embodiment includes a first polyimide layer (A) and a second polyimide layer (B) laminated on at least one surface of the first polyimide layer (A). This is a method for producing a polyimide film provided. The polyimide film obtained according to the present embodiment may have a polyimide layer other than the first polyimide layer (A) and the second polyimide layer (B), and may be laminated on any substrate. You may.

  The method for producing a polyimide film according to the present embodiment includes the following steps I to III.

(Step I):
In step I, a first polyimide layer (A) containing a polyimide having a ketone group is prepared. A polyimide having a ketone group has a ketone group (—CO—) in the molecule. The ketone group is derived from an acid dianhydride and / or a diamine compound which is a raw material for polyimide. That is, the polyimide constituting the first polyimide layer (A) contains a tetracarboxylic acid residue (1a) and a diamine residue (2a), and contains a tetracarboxylic acid residue (1a) or a diamine residue. One or both of (2a) include a residue having a ketone group.
In the present invention, “tetracarboxylic acid residue” refers to a tetravalent group derived from tetracarboxylic dianhydride, and “diamine residue” refers to a divalent group derived from a diamine compound. It represents a valence group. In the “diamine compound”, the hydrogen atoms in the two terminal amino groups may be substituted.

Examples of the residue having a ketone group contained in the tetracarboxylic acid residue (1a) include, for example,
3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 2,3 ′, 3,4′-benzophenonetetracarboxylic dianhydride, 2,2 ′, 3,3′-benzophenonetetracarboxylic acid "Tetracarboxylic dianhydride having a ketone group in the molecule, such as dianhydride, 4,4 '-(paraphenylenedicarbonyl) diphthalic anhydride, 4,4'-(metaphenylenedicarbonyl) diphthalic anhydride Residue derived from a “product”.

  In the tetracarboxylic acid residue (1a), other than the residue having a ketone group, for example, those derived from tetracarboxylic dianhydride generally used in the synthesis of polyimide, in addition to those shown in Examples described later. Residues may be mentioned.

As the residue having a ketone group contained in the diamine residue (2a), for example,
3,3′-diaminobenzophenone, 3,4′-diaminobenzophenone, 4,4′-diaminobenzophenone, 4,4′-bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] benzophenone, 4,4'-bis (4-aminophenoxy) benzophenone 4,4'-bis (3-aminophenoxy) benzophenone (BABP), 1,3-bis [4- (3-aminophenoxy) benzoyl] benzene (BABB), Residues derived from “diamine compounds having a ketone group in the molecule” such as 1,4-bis (4-aminobenzoyl) benzene and 1,3-bis (4-aminobenzoyl) benzene can be mentioned.

  In the diamine residue (2a), other than the residue having a ketone group, for example, in addition to those shown in Examples described later, there may be mentioned residues derived from a diamine compound generally used in the synthesis of polyimide. it can.

The first polyimide layer (A) may contain another polyimide other than the polyimide having a ketone group. However, in order to ensure sufficient adhesion with the second polyimide layer (B), 10 mol% or more of the polyimide having a ketone group is based on the total amount of the polyimide constituting the first polyimide layer (A). It is more preferable that 30 mol% or more of the polyimide is a polyimide having a ketone group.
The amount (as -CO-) of the ketone group present in the polyimide constituting the first polyimide layer (A) is 100 mol parts in total of the tetracarboxylic acid residue (1a) and the diamine residue (2a). Is preferably in the range of 5 to 200 mol parts, more preferably in the range of 15 to 100 mol parts. When the ketone group present in the polyimide constituting the first polyimide layer (A) is less than 5 mol parts, the functional group present in the resin layer containing the polyamic acid (b) laminated in the step II (for example, In some cases, the probability of interaction with the terminal amino group) is reduced, and sufficient adhesion between layers may not be obtained.

  As a method of forming the first polyimide layer (A), a method of applying a resin solution containing a polyamic acid (a) having a ketone group on an arbitrary base material (cast method), a method of forming an arbitrary base material It can be formed by a method of laminating a gel film containing a polyamic acid (a) having a ketone group thereon.

  In the casting method, the method of applying the resin solution containing the polyamic acid (a) is not particularly limited, and for example, the resin solution can be applied using a coater such as a comma, a die, a knife, a lip, or the like.

  Note that the first polyimide layer (A) may be in a state of being laminated with another resin layer, or may be in a state of being laminated on an arbitrary base material.

  Further, the first polyimide layer (A) is formed by laminating a resin layer containing a polyamic acid (a) having a ketone group on a substrate and imidizing the polyamic acid (a) together with the substrate. It is preferred that As described above, even when the first polyimide layer (A) is formed on the base material by the casting method, the imidation is completed before the second polyimide layer (B) is formed. Since water is removed, problems such as foaming and delamination do not occur.

  Further, the first polyimide layer (A) can be formed in a shape such as a cut sheet shape, a roll shape, or an endless belt shape. It is efficient to use a form that enables continuous production. Further, the first polyimide layer (A) is preferably a long roll formed from the viewpoint of further improving the effect of improving the wiring pattern accuracy on the circuit board.

(Step II)
In step II, a resin layer containing a polyamic acid (b) having a functional group having a property of interacting with the ketone group is laminated on the first polyimide layer (A) obtained in step I.
In step II, the “functional group having the property of interacting with a ketone group” includes, for example, a functional group capable of generating a physical interaction due to an intermolecular force or a chemical interaction due to a covalent bond with the ketone group. The group is not particularly limited as long as it is a group, and a typical example thereof is an amino group (—NH ₂ ).
When the functional group is an amino group, the polyamic acid (b) may be a polyamic acid having an amino group at a terminal, preferably a polyamic acid having most of terminal amino groups, more preferably Polyamic acids, all of whose ends are amino groups, can be used. Thus, the polyamic acid (b) having abundant amino terminals can be formed by adjusting the molar ratio of the two components so that the diamine compound is in excess with respect to the tetracarboxylic dianhydride in the raw material. . For example, by adjusting the charge ratio of the raw materials so that the amount of the tetracarboxylic dianhydride is less than 1 mol per 1 mol of the diamine compound, most of the synthesized polyamic acid is stochastically changed to the amino terminal ( —NH ₂ ). Diamine compound per mol, the charging ratio of the tetracarboxylic acid dianhydride is more than 1 mole, undesirable amino terminal (-NH ₂₎ for no longer remains almost. On the other hand, if the charging ratio of the tetracarboxylic dianhydride to the diamine compound is too small, the increase in the molecular weight of the polyamic acid does not sufficiently proceed. Therefore, the charging ratio of the tetracarboxylic dianhydride to 1 mol of the diamine compound is preferably, for example, in the range of 0.970 to 0.998 mol, and more preferably in the range of 0.980 to 0.995 mol. .

  The polyamic acid (b) can be synthesized using a tetracarboxylic dianhydride and a diamine compound generally used for the synthesis of polyimide as raw materials. The raw material may be a tetracarboxylic dianhydride having a ketone group in the molecule or a diamine compound having a ketone group in the molecule.

In addition, a polyamic acid (b) having abundant amino terminals is synthesized by using a compound (for example, a triamine compound) rich in an amino group in a molecule instead of part or all of the diamine compound as a raw material. It is also possible.
Furthermore, the charge ratio of the tetracarboxylic dianhydride and the diamine compound in the raw materials is made equimolar, and by adding a small amount of a compound containing an amino group (for example, a triamine compound), a polyamic acid having a rich amino terminal ( It is also possible to form a resin layer containing b).

  For the formation of the resin layer containing the polyamic acid (b), other polyamic acid may be mixed with the polyamic acid (b). As the other polyimide acid, a polyamic acid synthesized using tetracarboxylic dianhydride and a diamine compound, which are generally used for the synthesis of polyimide, as raw materials and in an equimolar ratio thereof can be used. However, from the viewpoint of ensuring sufficient adhesiveness with the first polyimide layer (A), the resin layer containing the polyamic acid (b) has a polyamic acid content of 10 mol% or more based on the total amount of the constituent polyamic acid. (B), and more preferably 30% by mole or more of the polyamic acid is the polyamic acid (b).

  The resin layer containing the polyamic acid (b) is formed by applying a resin solution containing the polyamic acid (b) on the first polyimide layer (A) (casting method). It can be formed by a method of laminating a gel film containing a polyamic acid (b) on the first layer. In order to increase the adhesion between the first polyimide layer (A) and the second polyimide layer (B), It is preferable to use a casting method. In addition, when forming the resin layer containing the polyamic acid (b), it is not necessary to previously perform a surface treatment such as a plasma treatment or a corona treatment on the surface of the first polyimide layer (A). It is also possible to do.

  In the casting method, the method of applying the resin solution containing the polyamic acid (b) is not particularly limited. For example, the resin solution can be applied with a coater such as a comma, a die, a knife, and a lip.

The resin layer containing the polyamic acid (b) thus obtained contains the tetracarboxylic acid residue (1b) and the diamine residue (2b), and is contained in 1 mole of the diamine residue (2b). Tetracarboxylic acid residue (1b) is contained in less than 1 mol, preferably in the range of 0.970 to 0.998 mol, more preferably in the range of 0.980 to 0.995 mol, and the amino terminal (-NH It becomes a resin layer containing ₂ ) abundantly.

(Step III)
In Step III, the resin layer containing the polyamic acid (b) is heat-treated together with the first polyimide layer (A), and the polyamic acid (b) is imidized to form a second polyimide layer (B).
The method of imidization is not particularly limited, and for example, a heat treatment such as heating at a temperature in the range of 80 to 400 ° C. for a time in the range of 1 to 60 minutes is preferably employed. When a metal layer is included, heat treatment in a low-oxygen atmosphere is preferable to suppress oxidation.Specifically, under an inert gas atmosphere such as nitrogen or a rare gas, a reducing gas atmosphere such as hydrogen, or a vacuum It is preferably carried out in

  In parallel with the imidation, a ketone group present in the polyimide chain of the first polyimide layer (A) and the functional group present in the resin layer containing the polyamic acid (b) (for example, abundant terminal Interaction occurs between the first polyimide layer (A) and the second polyimide layer (B), and the adhesion between the first polyimide layer (A) and the second polyimide layer (B) is a property of the polyimide constituting both layers (for example, thermoplastic). Or non-thermoplastic, etc.). Although all the mechanisms of such an interaction have not been elucidated, when the functional group is an amino group, one possibility is that the heat treatment at the time of imidizing the polyamic acid (b) causes It is presumed that an imine bond has occurred between the ketone group and the terminal amino group. That is, a heating causes a dehydration condensation reaction between the ketone group in the polyimide chain of the first polyimide layer (A) and the amino group at the terminal of the polyamic acid (b) to form an imine bond. Is chemically bonded to the second polyimide layer (B) after imidization, whereby the first polyimide layer (A) and the second polyimide layer (B) are chemically bonded to each other. It is presumed that the adhesive strength is increased.

  If the first polyimide layer (A) and the second polyimide layer (B) have the opposite relationship, the effect of improving the adhesion between the layers cannot be obtained. That is, first, a resin layer containing a polyamic acid (b) having a functional group having a property of interacting with a ketone group is imidized to form a first polyimide layer, and a polyamic acid having a ketone group is formed thereon. When a resin layer containing (a) is formed and then imidized by heat treatment to form a second polyimide layer, the adhesion between the first and second layers is determined by the properties of the polyimide constituting both layers (for example, , Thermoplastic or non-thermoplastic, etc.). It is considered that the reason for this is that in the cured polyimide, the movement of the terminal amino group as the functional group is restricted and the reactivity is reduced, so that the above-mentioned interaction hardly occurs.

  The first polyimide layer (A) and the second polyimide layer (B) may contain an inorganic filler as needed. Specific examples include silicon dioxide, aluminum oxide, magnesium oxide, beryllium oxide, boron nitride, aluminum nitride, silicon nitride, aluminum fluoride, calcium fluoride, and the like. These can be used alone or in combination of two or more.

  Through the above steps I to III, a polyimide film having excellent adhesion between the first polyimide layer (A) and the second polyimide layer (B) is produced without causing a decrease in throughput due to an increase in the number of steps. be able to.

[Second Embodiment: Method for Manufacturing Metal-Clad Laminate]
Production of a metal-clad laminate including a metal layer, a first polyimide layer (A), and a second polyimide layer (B) laminated on one surface of the first polyimide layer (A) A method comprising the following steps i to iv:

(Step i)
In step i, at least one or more polyamic acid resin layers having a polyamic acid (a) resin layer having a ketone group on the surface layer are formed on the metal layer.

  As the metal layer, a metal foil can be preferably used. The material of the metal foil is not particularly limited. For example, copper, stainless steel, iron, nickel, beryllium, aluminum, zinc, indium, silver, gold, tin, zirconium, tantalum, titanium, lead, magnesium, manganese and the like And the like. Among them, copper or a copper alloy is particularly preferable. As the copper foil, a rolled copper foil or an electrolytic copper foil may be used, and a commercially available copper foil can be preferably used.

  In the present embodiment, for example, when the metal layer is used for manufacturing an FPC, the preferred thickness is in the range of 3 to 50 μm, and more preferably in the range of 5 to 30 μm.

  The surface of the metal foil used as the metal layer may be subjected to surface treatment such as rust prevention treatment, siding, aluminum alcoholate, aluminum chelate, and silane coupling agent. In addition, the metal foil can be in a shape such as a cut sheet shape, a roll shape, or an endless belt shape. It is efficient to use a simple format. Further, from the viewpoint of further improving the effect of improving the accuracy of the wiring pattern on the circuit board, the metal foil is preferably a roll formed in a long shape.

In forming the first polyimide layer (A), at least one or more resin layers of polyamic acid are formed on the metal layer so that the resin layer containing the polyamic acid (a) having a ketone group becomes a surface layer. To form In this case, it can be formed by a method of applying a polyamic acid resin solution on the metal layer (casting method), a method of laminating a gel film containing the polyamic acid (a) on the metal layer, or the like.
Note that an arbitrary resin layer (including a resin layer of another polyamic acid) may be provided between the metal layer and the resin layer containing the polyamic acid (a) having a ketone group. Can form a resin layer containing a polyamic acid (a) having a ketone group on the arbitrary resin layer by the above method. When a resin layer of a polyamic acid (a) having a ketone group is directly formed on the metal layer, a cast method is used in order to increase the adhesion between the metal layer and the first polyimide layer (A). Is preferred.

  In the casting method, the method of applying the resin solution containing the polyamic acid (a) is not particularly limited, and for example, the resin solution can be applied using a coater such as a comma, a die, a knife, a lip, or the like.

(Step ii)
In step ii, the polyamic acid resin layer having a resin layer containing a polyamic acid (a) having a ketone group in the surface layer is heat-treated together with the metal layer to imidize the polyamic acid. As a result, an intermediate is formed in which the polyimide layer having the first polyimide layer (A) containing the polyimide having a ketone group as a surface layer is laminated on the metal layer.

  The imidization of the polyamic acid can be performed by the method described in the step (III) of the first embodiment. In the present embodiment, even when a resin layer of a polyamic acid having a surface layer with a resin layer containing a polyamic acid (a) having a ketone group is formed on a metal foil by a casting method, the second polyimide Since the imidization is completed before the formation of the layer (B), the solvent and the imidized water are removed, so that problems such as foaming and delamination do not occur.

(Step iii)
In step iii, a resin layer containing a polyamic acid (b) having a functional group having a property of interacting with the ketone group is laminated on the first polyimide layer (A).
This step iii can be carried out in the same manner as in step II of the first embodiment.

(Step iv)
The resin layer containing the polyamic acid (b) laminated on the intermediate in step iii is heat-treated together with the intermediate to imidize the polyamic acid (b) to form a second polyimide layer (B).
This step iv can be carried out in the same manner as step III of the first embodiment.

  By the above steps i to iv, a metal-clad laminate excellent in adhesion between the first polyimide layer (A) and the second polyimide layer (B) can be obtained without causing a decrease in throughput due to an increase in the number of steps. Can be manufactured.

  Other configurations and effects in the present embodiment are the same as those in the first embodiment.

<Polyimide>
Next, a preferred polyimide for forming the first polyimide layer (A) and the second polyimide layer (B) will be described. In forming the first polyimide layer (A), the above-mentioned “tetracarboxylic dianhydride having a ketone group in the molecule” and / or “diamine compound having a ketone group in the molecule” and generally a polyimide It is preferable to use a combination of an acid anhydride component and a diamine component used as a raw material for synthesis. In forming the second polyimide layer (B), an acid anhydride component and a diamine component generally used as a raw material for synthesizing polyimide can be used without any particular limitation.

  In the polyimide film or the metal-clad laminate, the polyimide constituting the first polyimide layer (A) may be either a thermoplastic polyimide or a non-thermoplastic polyimide. Thermoplastic polyimide is preferred because it is easy to secure adhesion.

Further, the polyimide constituting the second polyimide layer (B) may be either a thermoplastic polyimide or a non-thermoplastic polyimide. However, when the non-thermoplastic polyimide is used, the effect of the invention is remarkably exhibited.
That is, even when a resin layer of a polyamic acid, which is a precursor of a non-thermoplastic polyimide, is laminated on the first polyimide layer (A) which has been imidized by a method such as a casting method, imidization is usually performed. Has little adhesion between polyimide layers. However, in the present embodiment, the polyimide constituting the second polyimide layer (B) is thermoplastic or non-thermoplastic due to the interaction between the ketone group and the functional group (for example, terminal amino group). Regardless of whether or not there is, excellent adhesion between the first polyimide layer (A) and the first polyimide layer (A) can be obtained. Further, by making the second polyimide layer (B) a non-thermoplastic polyimide, it can function as a main layer (base layer) for securing the mechanical strength of the polyimide layer in the polyimide film or the metal-clad laminate. it can.

  From the above, it is not possible to form a structure in which a thermoplastic polyimide layer is laminated as the first polyimide layer (A) and a non-thermoplastic polyimide layer is laminated as the second polyimide layer (B) in the polyimide film or the metal-clad laminate. This is the most preferred embodiment.

In addition, “thermoplastic polyimide” generally refers to a polyimide whose glass transition temperature (Tg) can be clearly confirmed. In the present invention, 30 ° C. was measured using a dynamic viscoelasticity measuring device (DMA). Is a polyimide having a storage elastic modulus of 1.0 × 10 ⁹ Pa or more and a storage elastic modulus at 300 ° C. of less than 1.0 × 10 ⁸ Pa. In addition, “non-thermoplastic polyimide” generally refers to a polyimide that does not soften or exhibit adhesiveness even when heated, but in the present invention, it is measured using a dynamic viscoelasticity measuring device (DMA). It refers to a polyimide having a storage elastic modulus at 1.0 ° C. of 1.0 × 10 ⁹ Pa or more and a storage elastic modulus at 300 ° C. of 1.0 × 10 ⁸ Pa or more.

(Thermoplastic polyimide)
Thermoplastic polyimide is obtained by reacting an acid anhydride component with a diamine component. As the acid anhydride component used as a raw material of the thermoplastic polyimide, a general acid anhydride used for the synthesis of polyimide can be used without any particular limitation, and in particular, both the adhesion to the metal layer and the low dielectric property are compatible. In view of this, it is preferable to use a combination of biphenyltetracarboxylic dianhydride and pyromellitic dianhydride (PMDA). Biphenyltetracarboxylic dianhydride has an effect of lowering the glass transition temperature so as not to affect the decrease in solder heat resistance of the polyimide, and can secure a sufficient adhesive force with a metal layer or the like. In addition, biphenyltetracarboxylic dianhydride reduces the concentration of imide groups in the polyimide, facilitates the formation of an ordered structure of the polymer, and improves the dielectric properties by suppressing the movement of molecules. Furthermore, biphenyltetracarboxylic dianhydride contributes to the reduction in the number of polar groups in the polyimide, so that the hygroscopic property is improved. For this reason, biphenyltetracarboxylic dianhydride can reduce the transmission loss of FPC. In addition, the "imide group concentration" means a value obtained by dividing the molecular weight of the imide group (-(CO) ₂ -N-) in the polyimide by the molecular weight of the entire structure of the polyimide.

  Examples of the biphenyltetracarboxylic dianhydride include 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA), 2,3 ′, 3,4′-biphenyltetracarboxylic dianhydride, 2,2 ', 3,3'-biphenyltetracarboxylic dianhydride and the like can be mentioned. By using biphenyltetracarboxylic dianhydride within the above range, an ordered structure with a rigid structure is formed, so that a low dielectric loss tangent is possible, and while being thermoplastic, gas permeability is low, A thermoplastic polyimide having excellent long-term heat resistance can be obtained. Pyromellitic dianhydride is a monomer that plays a role in controlling the glass transition temperature, and contributes to improving the solder heat resistance of polyimide.

  In the thermoplastic polyimide, an acid anhydride other than the above can be used as the acid anhydride component. Such acid anhydrides include, for example, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride, 4,4′-oxydiphthalic anhydride, 2,2 ′, 3,3′- 2,3,3 ′, 4′- or 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 2,3 ′, 3,4′-diphenylethertetracarboxylic dianhydride, bis ( 2,3-dicarboxyphenyl) ether dianhydride, 3,3 ", 4,4"-, 2,3,3 ", 4"-or 2,2 ", 3,3" -p-terphenyltetracarboxylic dianhydride, 2,2-bis (2,3- or 3,4-dicarboxyphenyl) -propane dianhydride, bis (2,3- or 3.4-dicarboxy) Phenyl) methane dianhydride, bis (2,3- or 3,4-dicarboxyphenyl) sulfone dianhydride, 1,1-bis (2,3- or 3,4-dicarboxyphenyl) ethane dianhydride 1,2,7,8-, 1,2,6,7- or 1 2,2,9,10-phenanthrene-tetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) tetrafluoropropane dianhydride Anhydride, 2,3,5,6-cyclohexane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1, 4,5,8-Naphthalenetetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6-tetracarboxylic dianhydride 2,2,6- or 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7- (or 1,4,5,8-) tetrachloronaphthalene -1,4,5,8- (or 2,3,6,7-) tetracarboxylic dianhydride, 2,3,8,9-, 3,4,9,10-, 4,5,10 , 11- or 5,6,1 , 12-Perylene-tetracarboxylic dianhydride, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, pyrazine-2,3,5,6-tetracarboxylic dianhydride, pyrrolidine-2 , 3,4,5-tetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride, 4,4'-bis (2,3-dicarboxyphenoxy) diphenylmethane dianhydride And 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] propane dianhydride.

  As the diamine component serving as a raw material of the thermoplastic polyimide, a general diamine used for the synthesis of polyimide can be used without any particular limitation, and is selected from diamine compounds represented by the following general formulas (1) to (8). It is preferable to contain at least one of these.

In the above formulas (1) to (7), R ₁ independently represents a monovalent hydrocarbon group having 1 to 6 carbon atoms or an alkoxy group, and the linking group A independently represents -O-, -S-, -CO _{-, - SO -, - SO} 2 -, - COO -, - CH 2 -, - C (CH 3) 2 -, - NH- or -CONH- represents a divalent group selected from, _{n 1} is independently Shows an integer of 0 to 4. However, those overlapping with Expression (2) are excluded from Expression (3), and those overlapping with Expression (4) are excluded from Expression (5). Here, “independently” means that in one or two or more of the above formulas (1) to (7), a plurality of linking groups A, a plurality of R _1, or a plurality of n ₁ are the same. Or may be different.

  In the above formula (8), the linking group X represents a single bond or -CONH-, and Y represents a monovalent hydrocarbon group or an alkoxy group having 1 to 3 carbon atoms which may be independently substituted with a halogen atom. And n represents an integer of 0 to 2, and p and q independently represent an integer of 0 to 4.

In the above formulas (1) to (8), the hydrogen atoms in the two terminal amino groups may be substituted, for example, -NR ₂ R ₃ (where R ₂ and R ₃ are independently Any substituent such as an alkyl group).

The diamine represented by the formula (1) (hereinafter sometimes referred to as “diamine (1)”) is an aromatic diamine having two benzene rings. The diamine (1) has a high flexibility by increasing the degree of freedom of the polyimide molecular chain because the amino group directly bonded to at least one benzene ring and the divalent linking group A are at the meta position. This is considered to contribute to the improvement of the flexibility of the polyimide molecular chain. Accordingly, the use of the diamine (1) increases the thermoplasticity of the polyimide. Here, the linking group _{A, -O -, - CH 2} -, - C (CH 3) 2 -, - CO -, - SO 2 -, - S- are preferred.

  Examples of the diamine (1) include 3,3′-diaminodiphenylmethane, 3,3′-diaminodiphenylpropane, 3,3′-diaminodiphenylsulfide, 3,3′-diaminodiphenylsulfone, and 3,3-diaminodiphenylether 3,4′-diaminodiphenyl ether, 3,4′-diaminodiphenylmethane, 3,4′-diaminodiphenylpropane, 3,4′-diaminodiphenylsulfide, 3,3′-diaminobenzophenone, (3,3′-bisamino ) Diphenylamine and the like.

  The diamine represented by the formula (2) (hereinafter sometimes referred to as “diamine (2)”) is an aromatic diamine having three benzene rings. Since the diamine (2) has at least one amino group directly bonded to the benzene ring and the divalent linking group A at the meta position, the degree of freedom of the polyimide molecular chain is increased, and the diamine (2) has high flexibility. This is considered to contribute to the improvement of the flexibility of the polyimide molecular chain. Accordingly, the use of the diamine (2) increases the thermoplasticity of the polyimide. Here, the connecting group A is preferably -O-.

  Examples of the diamine (2) include 1,4-bis (3-aminophenoxy) benzene, 3- [4- (4-aminophenoxy) phenoxy] benzeneamine, and 3- [3- (4-aminophenoxy) phenoxy] Benzenamine and the like can be mentioned.

  The diamine represented by the formula (3) (hereinafter sometimes referred to as “diamine (3)”) is an aromatic diamine having three benzene rings. The diamine (3) has a high flexibility by increasing the degree of freedom of the polyimide molecular chain because the two divalent linking groups A directly bonded to one benzene ring are at the meta position with each other. It is considered that this contributes to the improvement of the flexibility of the polyimide molecular chain. Accordingly, the use of the diamine (3) increases the thermoplasticity of the polyimide. Here, the connecting group A is preferably -O-.

  Examples of the diamine (3) include 1,3-bis (4-aminophenoxy) benzene (TPE-R), 1,3-bis (3-aminophenoxy) benzene (APB), and 4,4 ′-[2- Methyl- (1,3-phenylene) bisoxy] bisaniline, 4,4 ′-[4-methyl- (1,3-phenylene) bisoxy] bisaniline, 4,4 ′-[5-methyl- (1,3-phenylene) ) Bisoxy] bisaniline and the like. Among these, 1,3-bis (4-aminophenoxy) benzene (TPE-R) is particularly useful as a monomer that contributes to increasing the CTE of the thermoplastic polyimide, reduces the imide group concentration, and improves the dielectric properties. preferable.

The diamine represented by the formula (4) (hereinafter sometimes referred to as “diamine (4)”) is an aromatic diamine having four benzene rings. The diamine (4) has high flexibility by having at least one amino group directly bonded to the benzene ring and the divalent linking group A at the meta position, and is useful for improving the flexibility of the polyimide molecular chain. It is thought to contribute. Accordingly, the use of the diamine (4) increases the thermoplasticity of the polyimide. Here, the linking group _{A, -O -, - CH 2} -, - C (CH 3) 2 -, - SO 2 -, - CO -, - CONH- are preferred.

  Examples of the diamine (4) include bis [4- (3-aminophenoxy) phenyl] methane, bis [4- (3-aminophenoxy) phenyl] propane, bis [4- (3-aminophenoxy) phenyl] ether, [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy)] benzophenone, bis [4,4 ′-(3-aminophenoxy)] benzanilide and the like can be given.

  The diamine represented by the formula (5) (hereinafter sometimes referred to as “diamine (5)”) is an aromatic diamine having four benzene rings. The diamine (5) has a high flexibility by increasing the degree of freedom of the polyimide molecular chain because two divalent linking groups A directly bonded to at least one benzene ring are at meta positions with each other. This is considered to contribute to the improvement of the flexibility of the polyimide molecular chain. Accordingly, the use of the diamine (5) increases the thermoplasticity of the polyimide. Here, the connecting group A is preferably -O-.

  Examples of the diamine (5) include 4- [3- [4- (4-aminophenoxy) phenoxy] phenoxy] aniline and 4,4 ′-[oxybis (3,1-phenyleneoxy)] bisaniline. .

The diamine represented by the formula (6) (hereinafter sometimes referred to as “diamine (6)”) is an aromatic diamine having four benzene rings. The diamine (6) has high flexibility by having at least two ether bonds, and is considered to contribute to improvement in flexibility of the polyimide molecular chain. Accordingly, the use of the diamine (6) increases the thermoplasticity of the polyimide. Here, as the connecting group A, —C (CH ₃ ) ₂ —, —O—, —SO ₂ —, and —CO— are preferable.

  Examples of the diamine (6) include 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP), bis [4- (4-aminophenoxy) phenyl] ether (BAPE), and bis [4 -(4-aminophenoxy) phenyl] sulfone (BAPS), bis [4- (4-aminophenoxy) phenyl] ketone (BAPK) and the like. Among these, 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) is particularly preferred as a monomer that greatly contributes to the improvement in adhesion to the metal layer.

  The diamine represented by the formula (7) (hereinafter sometimes referred to as “diamine (7)”) is an aromatic diamine having four benzene rings. Since the diamine (7) has the highly flexible divalent linking group A on both sides of the diphenyl skeleton, it is considered that the diamine (7) contributes to the improvement of the flexibility of the polyimide molecular chain. Accordingly, the use of the diamine (7) increases the thermoplasticity of the polyimide. Here, the connecting group A is preferably -O-.

  Examples of the diamine (7) include bis [4- (3-aminophenoxy)] biphenyl and bis [4- (4-aminophenoxy)] biphenyl.

  The diamine represented by the general formula (8) (hereinafter sometimes referred to as “diamine (8)”) is an aromatic diamine having one to three benzene rings. Since the diamine (8) has a rigid structure, it has an action of giving an ordered structure to the entire polymer. Therefore, by using one or more of the diamines (1) to (7) and one or more of the diamines (8) in combination at a predetermined ratio, the dielectric loss tangent can be reduced, and the thermoplastic resin can have a low dielectric loss tangent. However, a polyimide having low gas permeability and excellent long-term heat resistance can be obtained. Here, the connecting group X is preferably a single bond or -CONH-.

  Examples of the diamine (8) include paraphenylenediamine (PDA), 4,4′-diamino-2,2′-dimethylbiphenyl (m-TB), 4,4′-diamino-3,3′-dimethyldiphenyl 4,4′-diamino-2,2′-n-propylbiphenyl (m-NPB), 2′-methoxy-4,4′-diaminobenzanilide (MABA), 4,4′-diaminobenzanilide (DABA) ), 2,2′-bis (trifluoromethyl) -4,4′-diaminobiphenyl and the like. Among these, 4,4′-diamino-2,2′-dimethylbiphenyl (m-TB) is particularly preferable as a monomer that greatly contributes to improvement of the dielectric properties of the thermoplastic polyimide, lower moisture absorption and higher heat resistance. .

  By using the diamines (1) to (7), the flexibility of the polyimide molecular chain can be improved and thermoplasticity can be imparted.

  In addition, by using the diamine (8), an ordered structure is formed throughout the polymer due to the rigid structure derived from the monomer, so that a low dielectric loss tangent can be achieved, and gas permeability is obtained while being thermoplastic. A polyimide which is low and has excellent long-term heat resistance is obtained.

  In the thermoplastic polyimide, a diamine other than the above can be used as the diamine component.

(Non-thermoplastic polyimide)
The non-thermoplastic polyimide is obtained by reacting an acid anhydride component and a diamine component. As the acid anhydride component serving as the raw material of the non-thermoplastic polyimide, a general acid anhydride used for the synthesis of polyimide can be used without any particular limitation, but in order to impart low dielectric properties, the acid anhydride component of the raw material It is preferable to use at least one selected from the group consisting of pyromellitic dianhydride (PMDA), biphenyltetracarboxylic dianhydride, and naphthalenetetracarboxylic dianhydride. Here, as the biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) is particularly preferable, and as the naphthalenetetracarboxylic dianhydride, 2,3 ′ , 6,7-Naphthalenetetracarboxylic dianhydride (NTCDA) is particularly preferred.

  PMDA can reduce the coefficient of thermal expansion (CTE) of polyimide. BPDA has the effect of lowering the glass transition temperature to such an extent that it does not affect the solder heat resistance of polyimide. In addition, BPDA reduces the imide group concentration of the polyimide, facilitates the formation of an ordered structure of the polymer, and improves the dielectric properties by suppressing the movement of molecules. In addition, BPDA improves the moisture absorption properties since it contributes to the reduction of the polar groups of the polyimide. Therefore, the transmission loss of FPC can be reduced by using BPDA.

  The non-thermoplastic polyimide can use an acid anhydride other than the above as an acid anhydride component.

  As the diamine component serving as a raw material of the non-thermoplastic polyimide, a general diamine used for the synthesis of polyimide can be used without any particular limitation, and the diamines (1) to (8) exemplified in the description of the thermoplastic polyimide can be used. Diamines selected from among them are preferred, and diamine (8) is more preferred.

  The diamine (8) is an aromatic diamine, and contributes to lowering the CTE and improving the dielectric properties, and further lowering the moisture absorption and increasing the heat resistance. Among the diamines (8), those in which Y is an alkyl group having 1 to 3 carbon atoms in the above general formula (8) are preferable, and 4,4′-diamino-2,2′-dimethyldiphenyl (m-TB) 4,4′-Diamino-3,3′-dimethyldiphenyl is more preferred. Among these, 4,4'-diamino-2,2'-dimethyldiphenyl (m-TB) is most preferred.

  As the non-thermoplastic polyimide, a diamine other than the above can be used as the diamine component as long as the effects of the present invention are not hindered.

(Synthesis of polyimide)
The polyimide constituting the polyimide layer can be produced by reacting an acid anhydride and a diamine in a solvent to form a precursor resin, and then heating and closing the ring. For example, the acid anhydride component and the diamine component are dissolved in an organic solvent in substantially equimolar amounts (when the second polyimide layer (B) is formed, the ratio of the diamine component is increased). By stirring at a temperature in the range of 30 ° C. for 30 minutes to 24 hours to carry out a polymerization reaction, a polyamic acid which is a precursor of polyimide is obtained. In the reaction, the reaction components are dissolved so that the generated precursor is in the range of 5 to 30% by weight, preferably 10 to 20% by weight in the organic solvent. Examples of the organic solvent used for the polymerization reaction include N, N-dimethylformamide, N, N-dimethylacetamide (DMAC), N-methyl-2-pyrrolidone, 2-butanone, dimethylsulfoxide, dimethyl sulfate, cyclohexanone, and dioxane. , Tetrahydrofuran, diglyme, triglyme and the like. Two or more of these solvents can be used in combination, and further, an aromatic hydrocarbon such as xylene or toluene can be used in combination. The amount of the organic solvent used is not particularly limited, but may be such that the concentration of the polyamic acid solution (polyimide precursor solution) obtained by the polymerization reaction is about 5 to 30% by weight. It is preferable to use it after adjusting.

  In the synthesis of polyimide, each of the above-mentioned acid anhydrides and diamines may be used alone or in combination of two or more. By selecting the types of the acid anhydride and the diamine and the respective molar ratios when using two or more acid anhydrides or diamines, it is possible to control the thermal expansion property, the adhesive property, the glass transition temperature, and the like. .

  Usually, the synthesized precursor is advantageously used as a reaction solvent solution, but can be concentrated, diluted, or replaced with another organic solvent if necessary. Further, the precursor is generally used because it is excellent in solvent solubility. The method of imidizing the precursor is not particularly limited. For example, a heat treatment in which the precursor is heated in the solvent under a temperature condition of 80 to 400 ° C. for 1 to 24 hours is suitably employed.

  As described above, the polyimide film obtained in the first embodiment and the metal-clad laminate obtained in the second embodiment consist of the first polyimide layer (A) and the second polyimide layer (B). It has excellent adhesion and can improve the reliability of electronic devices by being used as a circuit board material represented by FPC.

<Circuit board>
The circuit board can be manufactured by processing a metal layer of the metal-clad laminate obtained by the method for manufacturing a metal-clad laminate of the second embodiment into a pattern by a conventional method to form a wiring layer. it can. The patterning of the metal layer can be performed by any method using, for example, photolithography technology and etching.

  When manufacturing a circuit board, for example, processes such as through-hole processing in a previous process and terminal plating and external shape processing in a subsequent process, which are usually performed, can be performed according to a conventional method.

  Examples will be shown below, and the features of the present invention will be described more specifically. However, the scope of the present invention is not limited to the examples. In the following examples, various measurements and evaluations are as follows unless otherwise specified.

[Viscosity measurement]
The viscosity of the resin was measured at 25 ° C. using an E-type viscometer (trade name: DV-II + Pro, manufactured by Brookfield). The rotation speed was set so that the torque became 10% to 90%, and two minutes after the start of the measurement, the value when the viscosity was stabilized was read.

[Measurement of peel strength]
The peel strength was measured by using a tensilon tester (trade name: Strograph VE-1D, manufactured by Toyo Seiki Seisaku-sho, Ltd.), fixing the second polyimide layer side of the sample having a width of 10 mm to an aluminum plate with a double-sided tape, and removing the first polyimide. The metal-clad laminate on the layer side was pulled in the direction of 180 ° at a speed of 50 mm / min, and the force at the time of peeling between the first polyimide layer and the second polyimide layer was determined.

[Evaluation of foaming]
When peeling is confirmed between the first polyimide layer and the second polyimide layer, or when the polyimide layer is cracked, it is regarded as “foamed”, and when there is no peeling or cracking, “no foaming”. And

Abbreviations used in Examples and Comparative Examples indicate the following compounds.
m-TB: 2,2'-dimethyl-4,4'-diaminobiphenyl TPE-R: 1,3-bis (4-aminophenoxy) benzene APB: 1,3-bis (3-aminophenoxy) benzene TPE- Q: 1,4-bis (4-aminophenoxy) benzene BAPP: 2,2-bis [4- (4-aminophenoxy) phenyl] propane 4,4′-DAPE: 4,4′-diaminodiphenyl ether 3,4 '-DAPE: 3,4'-diaminodiphenyl ether PDA: p-phenylenediamine TFMB: 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl PMDA: pyromellitic dianhydride BPDA: 3, 3 ', 4,4'-biphenyltetracarboxylic dianhydride BTDA: 3,3', 4,4'-benzophenonetetracarboxylic dianhydride ODPA 4,4'-oxydiphthalic dianhydride DMAc: N, N-dimethylacetamide

(Synthesis example 1)
45.989 g of m-TB (216.63 mmol), 15.832 g of TPE-R (54.16 mmol) and 680 g of DMAc were charged into a 1000 ml separable flask, and the mixture was stirred at room temperature under a nitrogen stream. After complete dissolution, 58.179 g of PMDA (266.73 mmol) was added and stirred at room temperature for 4 hours to obtain a polyamic acid solution A. The viscosity of the obtained polyamic acid solution A was 22,000 cP.

(Synthesis example 2)
9.244 g of 4,4'-DAPE (46.16 mmol) and 176 g of DMAc were charged into a 300 ml separable flask, and the mixture was stirred at room temperature under a nitrogen stream. After complete dissolution, 14.756 g of BTDA (45.79 mmol) was added, and the mixture was stirred at room temperature for 4 hours to obtain a polyamic acid solution B. The viscosity of the obtained polyamic acid solution B was 1,200 cP.

(Synthesis example 3)
11.464 g of TPE-Q (39.22 mmol) and 176 g of DMAc were charged into a 300 ml separable flask, and the mixture was stirred at room temperature under a nitrogen stream. After complete dissolution, 12.536 g of BTDA (38.90 mmol) was added, and the mixture was stirred at room temperature for 4 hours to obtain a polyamic acid solution C. The viscosity of the obtained polyamic acid solution C was 2,200 cP.

(Synthesis example 4)
In a 300 ml separable flask, 11.464 g of TPE-R (39.22 mmol) and 176 g of DMAc were charged, and the mixture was stirred at room temperature under a nitrogen stream. After complete dissolution, 12.536 g of BTDA (38.90 mmol) was added, and the mixture was stirred at room temperature for 4 hours to obtain a polyamic acid solution D. The viscosity of the obtained polyamic acid solution D was 1,100 cP.

(Synthesis example 5)
11.386 g of APB (38.95 mmol) and 176 g of DMAc were charged into a 300 ml separable flask and stirred at room temperature under a nitrogen stream. After complete dissolution, 12.614 g of BTDA (39.14 mmol) was added, and the mixture was stirred at room temperature for 4 hours to obtain a polyamic acid solution E. The viscosity of the obtained polyamic acid solution E was 200 cP.

(Synthesis example 6)
13.493 g of BAPP (32.87 mmol) and 176 g of DMAc were charged into a 300 ml separable flask, and the mixture was stirred at room temperature under a nitrogen stream. After complete dissolution, 10.507 g of BTDA (32.61 mmol) was added, and the mixture was stirred at room temperature for 4 hours to obtain a polyamic acid solution F. The viscosity of the obtained polyamic acid solution F was 1,400 cP.

(Synthesis example 7)
9.227 g of 3,4′-DAPE (46.08 mmol) and 176 g of DMAc were charged into a 300 ml separable flask, and the mixture was stirred at room temperature under a nitrogen stream. After complete dissolution, 14.773 g of BTDA (45.85 mmol) was added and stirred at room temperature for 4 hours to obtain a polyamic acid solution G. The viscosity of the obtained polyamic acid solution G was 500 cP.

(Synthesis example 8)
4.660 g of PDA (43.09 mmol), 2.157 g of 4,4'-DAPE (10.77 mmol) and 176 g of DMAc were added to a 300 ml separable flask, and the mixture was stirred at room temperature under a nitrogen stream. After complete dissolution, 17.183 g of BTDA (53.33 mmol) was added and stirred at room temperature for 4 hours to obtain a polyamic acid solution H. The viscosity of the obtained polyamic acid solution H was 1,500 cP.

(Synthesis example 9)
In a 300 ml separable flask, 12.053 g of TFMB (37.64 mmol) and 176 g of DMAc were charged, and the mixture was stirred at room temperature under a nitrogen stream. After complete dissolution, 11.947 g of BTDA (37.07 mmol) was added, and the mixture was stirred at room temperature for 4 hours to obtain a polyamic acid solution I. The viscosity of the obtained polyamic acid solution I was 1,200 cP.

(Synthesis example 10)
9.498 g of 4,4′-DAPE (47.43 mmol) and 176 g of DMAc were charged into a 300 ml separable flask, and the mixture was stirred at room temperature under a nitrogen stream. After complete dissolution, 7.581 g of BTDA (23.53 mmol) and 6.922 g of BPDA (23.53 mmol) were added, and the mixture was stirred at room temperature for 4 hours to obtain a polyamic acid solution J. The viscosity of the obtained polyamic acid solution J was 2,500 cP.

(Synthesis example 11)
9.727 g of 4,4′-DAPE (48.58 mmol) and 176 g of DMAc were charged into a 300 ml separable flask, and the mixture was stirred at room temperature under a nitrogen stream. After complete dissolution, 11.646 g of BTDA (36.14 mmol) and 2.628 g of PMDA (12.05 mmol) were added, and the mixture was stirred at room temperature for 4 hours to obtain a polyamic acid solution K. The viscosity of the obtained polyamic acid solution K was 1,100 cP.

(Synthesis Example 12)
4.575 g of 4,4′-DAPE (22.85 mmol), 4.850 g of m-TB (22.85 mmol), and 176 g of DMAc are charged into a 300 ml separable flask, and stirred at room temperature under a nitrogen stream. did. After complete dissolution, 14.576 g of BTDA (45.23 mmol) was added, and the mixture was stirred at room temperature for 4 hours to obtain a polyamic acid solution L. The viscosity of the obtained polyamic acid solution L was 1,100 cP.

(Synthesis Example 13)
9.807 g of 4,4'-DAPE (48.97 mmol) and 176 g of DMAc were charged into a 300 ml separable flask, and the mixture was stirred at room temperature under a nitrogen stream. After complete dissolution, 14.193 g of BPDA (48.24 mmol) was added and stirred at room temperature for 4 hours to obtain a polyamic acid solution M. The viscosity of the obtained polyamic acid solution M was 1,000 cP.

(Synthesis Example 14)
To a 1000 ml separable flask were charged 62.734 g of BAPP (152.82 mmol) and 704 g of DMAc, and the mixture was stirred at room temperature under a nitrogen stream. After complete dissolution, 33.266 g of PMDA (152.51 mmol) was added and stirred at room temperature for 4 hours to obtain a polyamic acid solution N. The viscosity of the obtained polyamic acid solution N was 4,800 cP.

(Synthesis Example 15)
38.27 g of m-TB (180.27 mmol) and 704 g of DMAc were charged into a 1000 ml separable flask, and the mixture was stirred at room temperature under a nitrogen stream. After complete dissolution, 57.102 g of BTDA (177.21 mmol) and 0.629 g of PMDA (2.88 mmol) were added, and the mixture was stirred at room temperature for 4 hours to obtain a polyamic acid solution O. The viscosity of the obtained polyamic acid solution O was 43,000 cP.

(Synthesis Example 16)
Into a 1000 ml separable flask, 19.536 g of PDA (180.66 mmol), 13.087 g of BAPP (31.88 mmol) and 704 g of DMAc were charged, and the mixture was stirred at room temperature under a nitrogen stream. After complete dissolution, 56.73 g of BPDA (192.82 mmol) and 6.646 g of ODPA (21.42 mmol) were added and stirred at room temperature for 4 hours to obtain a polyamic acid solution P. The viscosity of the obtained polyamic acid solution P was 51,000 cP.

(Synthesis Example 17)
76.91 g of BAPP (187.35 mmol) and 680 g of DMAc were charged into a 1000 ml separable flask, and the mixture was stirred at room temperature under a nitrogen stream. After complete dissolution, 34.805 g of PMDA (159.57 mmol) and 8.285 g of BPDA (28.16 mmol) were added, and the mixture was stirred at room temperature for 4 hours to obtain a polyamic acid solution Q. The viscosity of the obtained polyamic acid solution Q was 9,500 cP.

(Synthesis Example 18)
77.298 g of BAPP (188.30 mmol) and 680 g of DMAc were charged into a 1000 ml separable flask, and the mixture was stirred at room temperature under a nitrogen stream. After complete dissolution, 34.492 g of PMDA (158.13 mmol) and 8.210 g of BPDA (27.91 mmol) were added and stirred at room temperature for 4 hours to obtain a polyamic acid solution R. The viscosity of the obtained polyamic acid solution R was 2,200 cP.

(Synthesis Example 19)
50.803 g of m-TB (239.31 mmol), 7.773 g of TPE-R (26.59 mmol) and 680 g of DMAc were put into a 1000 ml separable flask, and the mixture was stirred at room temperature under a nitrogen stream. After complete dissolution, 45.934 g of PMDA (210.59 mmol) and 15.490 g of BPDA (52.65 mmol) were added, and the mixture was stirred at room temperature for 4 hours to obtain a polyamic acid solution S. The viscosity of the obtained polyamic acid solution S was 23,000 cP.

(Synthesis example 20)
44.203 g of m-TB (208.22 mmol), 6.763 g of TPE-R (23.14 mmol) and 680 g of DMAc were added to a 1000 ml separable flask, and the mixture was stirred at room temperature under a nitrogen stream. After complete dissolution, 59.043 g of BTDA (183.23 mmol) and 9.992 g of PMDA (45.81 mmol) were added, and the mixture was stirred at room temperature for 4 hours to obtain a polyamic acid solution T. The viscosity of the obtained polyamic acid solution T was 12,000 cP.

(Synthesis Example 21)
33.475 g of TPE-R (114.51 mmol), 14.346 g of TPE-Q (49.08 mmol) and 704 g of DMAc were put into a 1000 ml separable flask, and the mixture was stirred at room temperature under a nitrogen stream. After complete dissolution, 48.179 g of BPDA (163.75 mmol) was added and stirred at room temperature for 4 hours to obtain a polyamic acid solution U. The viscosity of the obtained polyamic acid solution U was 15,000 cP.

(Synthesis Example 22)
33.542 g of TPE-R (114.74 mmol), 14.375 g of TPE-Q (49.17 mmol) and 704 g of DMAc were put into a 1000 ml separable flask, and the mixture was stirred at room temperature under a nitrogen stream. After complete dissolution, 48.083 g of BPDA (163.42 mmol) was added and stirred at room temperature for 4 hours to obtain a polyamic acid solution V. The viscosity of the obtained polyamic acid solution V was 10,000 cP.

[Example 1]
On a 12 μm-thick electrolytic copper foil, a polyamic acid solution B to be a first polyimide layer was uniformly applied so as to have a cured thickness of 2 μm, and the temperature was gradually increased from 120 ° C. to 360 ° C. Removal of the solvent and imidation were performed. Next, a polyamic acid solution A to be a second polyimide layer was uniformly applied thereon so as to have a cured thickness of 25 μm, and then heated and dried at 120 ° C. for 3 minutes to remove the solvent. Thereafter, the temperature was increased stepwise from 130 ° C. to 360 ° C. to perform imidization, thereby preparing a metal-clad laminate 1. An adhesive tape was applied to the resin surface of the prepared metal-clad laminate 1 and a peeling test was performed by instantaneously peeling off the resin in the vertical direction. However, peeling between the first polyimide layer and the second polyimide layer was observed. Did not.

[Example 2]
A metal-clad laminate 2 was prepared in the same manner as in Example 1, except that the polyamic acid solution N was used instead of the polyamic acid solution A. A peeling test of the prepared metal-clad laminate 2 was performed in the same manner as in Example 1, but no peeling between the first polyimide layer and the second polyimide layer was observed.

[Example 3]
A metal-clad laminate 3 was prepared in the same manner as in Example 1 except that the polyamic acid solution C was used instead of the polyamic acid solution B. A peeling test of the prepared metal-clad laminate 3 was performed in the same manner as in Example 1, but no peeling between the first polyimide layer and the second polyimide layer was observed.

[Example 4]
A metal-clad laminate 4 was prepared in the same manner as in Example 1, except that the polyamic acid solution B was used instead of the polyamic acid solution B, and the polyamic acid solution N was used instead of the polyamic acid solution A. . A peeling test of the prepared metal-clad laminate 4 was performed in the same manner as in Example 1, but no peeling between the first polyimide layer and the second polyimide layer was observed.

[Example 5]
A metal-clad laminate 5 was prepared in the same manner as in Example 1 except that the polyamic acid solution D was used instead of the polyamic acid solution B. A peeling test of the prepared metal-clad laminate 5 was performed in the same manner as in Example 1, but no peeling between the first polyimide layer and the second polyimide layer was observed.

[Example 6]
A metal-clad laminate 6 was prepared in the same manner as in Example 1, except that the polyamic acid solution B was used instead of the polyamic acid solution B, and the polyamic acid solution N was used instead of the polyamic acid solution A. . A peeling test of the prepared metal-clad laminate 6 was performed in the same manner as in Example 1, but no peeling was observed between the first polyimide layer and the second polyimide layer.

[Example 7]
A metal-clad laminate 7 was prepared in the same manner as in Example 1, except that the polyamic acid solution E was used instead of the polyamic acid solution B. A peeling test of the prepared metal-clad laminate 7 was performed in the same manner as in Example 1, but no peeling was observed between the first polyimide layer and the second polyimide layer.

Example 8
A metal-clad laminate 8 was prepared in the same manner as in Example 1, except that the polyamic acid solution E was used instead of the polyamic acid solution B, and the polyamic acid solution N was used instead of the polyamic acid solution A. . A peeling test of the prepared metal-clad laminate 8 was performed in the same manner as in Example 1, but no peeling between the first polyimide layer and the second polyimide layer was observed.

[Example 9]
A metal-clad laminate 9 was prepared in the same manner as in Example 1 except that the polyamic acid solution F was used instead of the polyamic acid solution B. A peeling test of the prepared metal-clad laminate 9 was performed in the same manner as in Example 1, but no peeling between the first polyimide layer and the second polyimide layer was observed.

[Example 10]
The metal-clad laminate 10 was prepared in the same manner as in Example 1 except that the polyamic acid solution F was used instead of the polyamic acid solution B, and the polyamic acid solution N was used instead of the polyamic acid solution A. . A peeling test of the prepared metal-clad laminate 10 was performed in the same manner as in Example 1, but no peeling between the first polyimide layer and the second polyimide layer was observed.

[Example 11]
A metal-clad laminate 11 was prepared in the same manner as in Example 1, except that the polyamic acid solution G was used instead of the polyamic acid solution B. A peeling test of the prepared metal-clad laminate 11 was performed in the same manner as in Example 1, but no peeling between the first polyimide layer and the second polyimide layer was observed.

[Example 12]
A metal-clad laminate 12 was prepared in the same manner as in Example 1, except that the polyamic acid solution B was used instead of the polyamic acid solution B, and the polyamic acid solution N was used instead of the polyamic acid solution A. . A peel test of the prepared metal-clad laminate 12 was performed in the same manner as in Example 1, but no peeling between the first polyimide layer and the second polyimide layer was observed.

Example 13
A metal-clad laminate 13 was prepared in the same manner as in Example 1, except that the polyamic acid solution H was used instead of the polyamic acid solution B. A peel test of the prepared metal-clad laminate 13 was performed in the same manner as in Example 1, but no peeling between the first polyimide layer and the second polyimide layer was observed.

[Example 14]
The metal-clad laminate 14 was prepared in the same manner as in Example 1 except that the polyamic acid solution H was used instead of the polyamic acid solution B, and the polyamic acid solution N was used instead of the polyamic acid solution A. . In the same manner as in Example 1, a peeling test of the prepared metal-clad laminate 14 was performed, but no peeling between the first polyimide layer and the second polyimide layer was observed.

[Example 15]
A metal-clad laminate 15 was prepared in the same manner as in Example 1, except that the polyamic acid solution I was used instead of the polyamic acid solution B. In the same manner as in Example 1, a peel test of the prepared metal-clad laminate 15 was performed, but no peeling between the first polyimide layer and the second polyimide layer was observed.

[Example 16]
A metal-clad laminate 16 was prepared in the same manner as in Example 1, except that the polyamic acid solution I was used instead of the polyamic acid solution B, and the polyamic acid solution N was used instead of the polyamic acid solution A. . A peeling test of the prepared metal-clad laminate 16 was performed in the same manner as in Example 1, but no peeling between the first polyimide layer and the second polyimide layer was observed.

[Example 17]
A metal-clad laminate 17 was prepared in the same manner as in Example 1 except that the polyamic acid solution J was used instead of the polyamic acid solution B. A peeling test of the prepared metal-clad laminate 17 was performed in the same manner as in Example 1, but no peeling between the first polyimide layer and the second polyimide layer was observed.

[Example 18]
A metal-clad laminate 18 was prepared in the same manner as in Example 1, except that the polyamic acid solution B was used instead of the polyamic acid solution B, and the polyamic acid solution N was used instead of the polyamic acid solution A. . A peeling test of the prepared metal-clad laminate 18 was performed in the same manner as in Example 1, but no peeling between the first polyimide layer and the second polyimide layer was observed.

[Example 19]
A metal-clad laminate 19 was prepared in the same manner as in Example 1 except that the polyamic acid solution K was used instead of the polyamic acid solution B. A peeling test of the prepared metal-clad laminate 19 was performed in the same manner as in Example 1, but no peeling between the first polyimide layer and the second polyimide layer was observed.

[Example 20]
A metal-clad laminate 20 was prepared in the same manner as in Example 1 except that the polyamic acid solution K was used instead of the polyamic acid solution B, and the polyamic acid solution N was used instead of the polyamic acid solution A. . A peel test of the prepared metal-clad laminate 20 was performed in the same manner as in Example 1, but no peeling between the first polyimide layer and the second polyimide layer was observed.

[Example 21]
A metal-clad laminate 21 was prepared in the same manner as in Example 1, except that the polyamic acid solution L was used instead of the polyamic acid solution B. A peeling test of the prepared metal-clad laminate 21 was performed in the same manner as in Example 1, but no peeling between the first polyimide layer and the second polyimide layer was observed.

[Example 22]
A metal-clad laminate 22 was prepared in the same manner as in Example 1, except that the polyamic acid solution B was used instead of the polyamic acid solution B, and the polyamic acid solution N was used instead of the polyamic acid solution A. . A peeling test of the prepared metal-clad laminate 22 was performed in the same manner as in Example 1, but no peeling was observed between the first polyimide layer and the second polyimide layer.

[Example 23]
A metal-clad laminate 23 was prepared in the same manner as in Example 1, except that the polyamic acid solution O was used instead of the polyamic acid solution B. A peeling test of the prepared metal-clad laminate 23 was performed in the same manner as in Example 1, but no peeling between the first polyimide layer and the second polyimide layer was observed.

[Example 24]
A metal-clad laminate 24 was prepared in the same manner as in Example 1, except that the polyamic acid solution B was used instead of the polyamic acid solution B, and the polyamic acid solution N was used instead of the polyamic acid solution A. . In the same manner as in Example 1, the prepared metal-clad laminate 24 was subjected to a peel test, but no peeling between the first polyimide layer and the second polyimide layer was observed.

[Example 25]
A metal-clad laminate 25 was prepared in the same manner as in Example 1, except that the polyamic acid solution T was used instead of the polyamic acid solution B. In the same manner as in Example 1, a peeling test of the prepared metal-clad laminate 25 was performed, but no peeling between the first polyimide layer and the second polyimide layer was observed.

[Example 26]
A metal-clad laminate 26 was prepared in the same manner as in Example 1, except that the polyamic acid solution T was used instead of the polyamic acid solution B, and the polyamic acid solution N was used instead of the polyamic acid solution A. . A peeling test of the prepared metal-clad laminate 26 was performed in the same manner as in Example 1, but no peeling between the first polyimide layer and the second polyimide layer was observed.

Comparative Example 1
A metal-clad laminate 27 was prepared in the same manner as in Example 1, except that the polyamic acid solution M was used instead of the polyamic acid solution B. When a peel test was performed on the prepared metal-clad laminate 27 in the same manner as in Example 1, delamination between the first polyimide layer and the second polyimide layer occurred.

Comparative Example 2
A metal-clad laminate 28 was prepared in the same manner as in Example 1 except that the polyamic acid solution M was used instead of the polyamic acid solution B, and the polyamic acid solution N was used instead of the polyamic acid solution A. . A peel test of the prepared metal-clad laminate 28 was performed in the same manner as in Example 1. As a result, delamination of the first polyimide layer and the second polyimide layer occurred.

Comparative Example 3
A metal-clad laminate 29 was prepared in the same manner as in Example 1, except that the polyamic acid solution N was used instead of the polyamic acid solution B. A peel test of the prepared metal-clad laminate 29 was performed in the same manner as in Example 1. As a result, delamination of the first polyimide layer and the second polyimide layer occurred.

Comparative Example 4
A metal-clad laminate 30 was prepared in the same manner as in Example 1, except that the polyamic acid solution A was used instead of the polyamic acid solution A. When a peel test was performed on the prepared metal-clad laminate 30 in the same manner as in Example 1, delamination between the first polyimide layer and the second polyimide layer occurred.

Comparative Example 5
A metal-clad laminate 31 was prepared in the same manner as in Example 1 except that the polyamic acid solution A was used instead of the polyamic acid solution B, and that the polyamic acid solution B was used instead of the polyamic acid solution A. . A peel test of the prepared metal-clad laminate 31 was performed in the same manner as in Example 1. As a result, delamination of the first polyimide layer and the second polyimide layer occurred.

[Example 27]
A metal-clad laminate 32 was prepared in the same manner as in Example 1 except that the temperature-raising time from 130 ° C. to 360 ° C. after the application of the polyamic acid solution A was reduced to １ ／, but foaming was confirmed. Did not.

[Example 28]
In the same manner as in Example 1 except that the polyamic acid solution A was used in place of the polyamic acid solution B, and the heating time from 130 ° C. to 360 ° C. after the application of the polyamic acid solution A was shortened to 1/3. Thus, a metal-clad laminate 33 was prepared, but no foaming was confirmed.

Comparative Example 6
In the same manner as in Example 1 except that the polyamic acid solution M was used in place of the polyamic acid solution B, and the heating time from 130 ° C. to 360 ° C. after the application of the polyamic acid solution A was shortened to 1/3. When the metal-clad laminate 34 was prepared, foaming occurred.

Comparative Example 7
In the same manner as in Example 1 except that the polyamic acid solution N was used in place of the polyamic acid solution B, and the heating time from 130 ° C. to 360 ° C. after the application of the polyamic acid solution A was shortened to 1/3. When the metal-clad laminate 35 was prepared, foaming occurred.

[Example 29]
After a polyamic acid solution O serving as a first polyimide layer was applied on a stainless steel base material, it was dried at 120 ° C. to prepare a polyamic acid gel film. After the prepared gel film was peeled from the stainless steel base material, it was fixed to a tenter clip, and the temperature was gradually increased from 130 ° C. to 360 ° C. to perform imidization, thereby preparing a 12.5 μm-thick polyimide film 36. A polyamic acid solution R to be a second polyimide layer was applied to the prepared polyimide film 36 so as to have a cured thickness of 3 μm, and dried at 120 ° C. Thereafter, the temperature was increased stepwise from 130 ° C. to 360 ° C. to perform imidization, thereby preparing a laminated polyimide film 36. The prepared laminated polyimide film 36 was cut with a cutter, and no delamination between the first polyimide layer and the second polyimide layer was observed by SEM observation.

[Example 30]
A laminated polyimide film 37 was prepared in the same manner as in Example 29, except that the polyamic acid solution T was used instead of the polyamic acid solution O. No delamination was observed on the prepared laminated polyimide film 37 by SEM observation.

[Example 31]
Laminating was performed in the same manner as in Example 29, except that the thickness of the first polyimide layer was 17 μm, and that the thickness after curing was 4 μm using a polyamic acid solution V instead of the polyamic acid solution R. A polyimide film 38 was prepared. No delamination was observed by SEM observation of the prepared laminated polyimide film 38.

[Example 32]
Instead of the polyamic acid solution O, a polyamic acid solution T was used, the thickness of the first polyimide layer was set to 17 μm, and instead of the polyamic acid solution R, a polyamic acid solution V was used, and the cured thickness was used. Was set to 4 μm, and a laminated polyimide film 39 was prepared in the same manner as in Example 29. No delamination was observed by SEM observation of the prepared laminated polyimide film 39.

Comparative Example 8
A laminated polyimide film 40 was prepared in the same manner as in Example 29, except that the polyamic acid solution R was used instead of the polyamic acid solution R. SEM observation of the prepared laminated polyimide film 40 confirmed delamination.

Comparative Example 9
A laminated polyimide film 41 was prepared in the same manner as in Example 29 except that the polyamic acid solution O was used instead of the polyamic acid solution O. SEM observation of the prepared laminated polyimide film 41 confirmed delamination.

Comparative Example 10
Laminating was performed in the same manner as in Example 29 except that the thickness of the first polyimide layer was 17 μm, and that the thickness after curing was 4 μm using a polyamic acid solution U instead of the polyamic acid solution R. A polyimide film 42 was prepared. SEM observation of the prepared laminated polyimide film 42 confirmed delamination.

[Example 33]
On a 12 μm-thick electrolytic copper foil, a polyamic acid solution T to be a first polyimide layer was uniformly applied so as to have a cured thickness of 25 μm, and then the temperature was increased stepwise from 120 ° C. to 360 ° C. Removal of the solvent and imidation were performed. Next, a polyamic acid solution S to be a second polyimide layer was uniformly applied thereon so as to have a cured thickness of 25 μm, and then heated and dried at 120 ° C. to remove the solvent. Thereafter, the temperature was increased stepwise from 130 ° C. to 360 ° C. to perform imidization, thereby preparing a metal-clad laminate 43. The peel strength of the first polyimide layer and the second polyimide layer in the prepared metal-clad laminate 43 was 1.5 kN / m or more.

[Example 34]
The polyamic acid solution S was uniformly applied on a 12 μm-thick electrolytic copper foil so that the thickness after curing became 23 μm, and was heated and dried at 120 ° C. to remove the solvent. The polyamic acid solution B was uniformly applied thereon so as to have a cured thickness of 2 μm, and dried by heating at 120 ° C. to remove the solvent. Thereafter, the temperature was increased stepwise from 130 ° C. to 360 ° C. to perform imidization, thereby forming a first polyimide layer. Next, a polyamic acid solution S to be a second polyimide layer was uniformly applied thereon so as to have a cured thickness of 25 μm, and then heated and dried at 120 ° C. to remove the solvent. Thereafter, the temperature was raised stepwise from 130 ° C. to 360 ° C. to perform imidization, thereby preparing a metal-clad laminate 44. The peel strength of the first polyimide layer and the second polyimide layer in the prepared metal-clad laminate 44 was 1.5 kN / m or more.

Comparative Example 11
A metal-clad laminate 45 was prepared in the same manner as in Example 33 except that the polyamic acid solution T was used instead of the polyamic acid solution T. The peel strength of the first polyimide layer and the second polyimide layer in the prepared metal-clad laminate 45 was 0.1 kN / m or less.

Comparative Example 12
A metal-clad laminate 46 was prepared in the same manner as in Example 34 except that the polyamic acid solution M was used instead of the polyamic acid solution B. The peel strength of the first polyimide layer and the second polyimide layer in the prepared metal-clad laminate 46 was 0.1 kN / m or less.

Reference Example 0.45 g of phthalic anhydride (3.02 mmol) was added to 100 g of polyamic acid solution A, and the mixture was stirred for 4 hours to prepare a polyamic acid solution A2. When the metal-clad laminate 47 was prepared in the same manner as in Example 1 except that the polyamic acid solution A2 was used instead of the polyamic acid solution A, foaming occurred. Further, a peeling test of the prepared metal-clad laminate 47 was performed in the same manner as in Example 1. As a result, delamination between the first polyimide layer and the second polyimide layer occurred.
This is presumably because the amino group of the second polyimide layer reacted with phthalic anhydride, so that there was no functional group capable of reacting with the first polyimide layer, and no chemical adhesion between the resin layers occurred.

  The embodiments of the present invention have been described in detail for the purpose of illustration, but the present invention is not limited to the above embodiments.

Claims (6)

A method for producing a polyimide film, comprising: a first polyimide layer (A); and a second polyimide layer (B) laminated on at least one surface of the first polyimide layer (A),
The following steps I to III;
I) a step of preparing a first polyimide layer (A) containing a polyimide having a ketone group;
II) laminating a resin layer containing a polyamic acid (b) having a functional group having a property of interacting with the ketone group on the first polyimide layer (A);
III) a step of heat-treating the resin layer containing the polyamic acid (b) together with the first polyimide layer (A) to imidize the polyamic acid (b) to form a second polyimide layer (B);
A method for producing a polyimide film, comprising:   The polyimide constituting the first polyimide layer (A) contains a tetracarboxylic acid residue (1a) and a diamine residue (2a), and the tetracarboxylic acid residue (1a) and the diamine residue The method for producing a polyimide film according to claim 1, wherein the ketone group is 5 mol parts or more based on 100 mol parts in total of the group (2a).   The resin layer containing the polyamic acid (b) contains a tetracarboxylic acid residue (1b) and a diamine residue (2b), and the tetracarboxylic acid is contained in 1 mol of the diamine residue (2b). 3. The method for producing a polyimide film according to claim 1, wherein the residue (1b) is less than 1 mol.   The first polyimide layer (A) is formed by laminating a resin layer containing a polyamic acid (a) having a ketone group on a substrate and imidizing the polyamic acid (a) together with the substrate. The method for producing a polyimide film according to any one of claims 1 to 3, characterized in that: Production of a metal-clad laminate including a metal layer, a first polyimide layer (A), and a second polyimide layer (B) laminated on one surface of the first polyimide layer (A) The method
The following steps i to iv:
i) a step of forming at least one or more polyamic acid resin layers having a resin layer containing a polyamic acid (a) having a ketone group on the surface layer on the metal layer;
ii) heat treating the polyamic acid resin layer together with the metal layer to imidize the polyamic acid, thereby forming a first polyimide layer (A) containing a polyimide having a ketone group on the metal layer; Step of forming an intermediate in which a polyimide layer having a part is laminated,
iii) laminating a resin layer containing a polyamic acid (b) having a functional group having a property of interacting with the ketone group on the first polyimide layer (A);
iv) heat treating the resin layer of the polyamic acid (b) together with the intermediate, and imidizing the polyamic acid (b) to form a second polyimide layer (B);
A method for producing a metal-clad laminate, comprising: A method for manufacturing a circuit board, comprising a step of performing a wiring circuit processing on the metal layer of the metal-clad laminate manufactured by the method according to claim 5.