JP6743697B2 - Multilayer polyimide film, method for producing multilayer polyimide film, polyimide laminate using the same, and copolymerized polyimide used therein - Google Patents

Description

The present invention is easily obtained by a conventional polyimide film manufacturing method, can be bonded at low temperature in a short time, a new multilayer polyimide film that realizes high heat resistance and high adhesive strength, a method for manufacturing a multilayer polyimide film, and It relates to a polyimide laminate using the same.

2. Description of the Related Art In recent years, electronic devices have become highly functional, highly functional, and miniaturized, and electronic components used in connection with these have been required to be miniaturized and lightened. Therefore, semiconductor device packaging methods and wiring materials or wiring components for mounting them have also been required to have higher density, higher functionality, and higher performance. In particular, there is a demand for a material having good adhesiveness that can be suitably used as a high-density mounting material such as a semiconductor package or a printed wiring board material such as a multilayer FPC. Further, along with the increase in the frequency of electronic devices, there is a strong demand for lower dielectric loss tangent of a circuit board, particularly an insulating layer adjacent to a metal forming a circuit.

Conventionally, epoxy-based resins exhibiting good heat resistance and adhesiveness have been widely used in semiconductor packages and other mounting materials, but their dielectric loss tangent is large, making it difficult to cope with high frequencies. On the other hand, as a resin having a small dielectric loss tangent, for example, Patent Document 1 discloses 4,4′-(4,4′-isopropylidenediphenoxy)bis(phthalic anhydride) (BPADA) and 1,3-bis. A polyimide obtained from a specific diamine such as (3-aminophenoxy)benzene (APB) has been reported. Similarly, Patent Documents 3 and 4 also report polyimides obtained from BPADA and APB. In Patent Document 2, 4,4′-(4,4′-isopropylidenediphenoxy)bis(phthalic anhydride) (BPADA) and oxydianiline (ODA) are provided on the surface layer of the low linear expansion polyimide layer. A polyimide film having a thermoplastic polyimide layer as a main component and a laminate thereof are disclosed.

JP, 2005-42091, A Japanese Patent Publication No. 2006-521221 JP, 2003-306649, A JP 2004-155911 A

Since the polyimide composed of BPADA and APB described in Patent Documents 1 and 3 and 4 has a low glass transition temperature of about 175° C., a smooth film is formed in a continuous film manufacturing process involving heat treatment at 250° C. or higher. Hard to get. On the other hand, with the technique described in Patent Document 2, although a polyimide film having excellent flatness can be obtained, the glass transition temperature of the thermoplastic polyimide is 200° C. or higher, and heating at 300 to 350° C. is required for bonding. Met.

For these reasons, there has been a need for a new multi-layer polyimide film which can be easily obtained by the conventional method for producing a polyimide film, can be bonded at a low temperature in a short time, and can realize high heat resistance and high adhesive strength.

The present invention is easily obtained by a conventional polyimide film manufacturing method, can be bonded at low temperature in a short time, a new multilayer polyimide film that realizes high heat resistance and high adhesive strength, a method for manufacturing a multilayer polyimide film, and It is intended to provide a polyimide laminate using the same. It is also preferable to have low dielectric properties.

Therefore, as a result of intensive studies, the inventors of the present invention used a polyimide containing BPADA and APB as the main components for the thermoplastic polyimide layer (A), and made it a multilayer polyimide with the heat resistant polyimide layer (B). As a result, they have found that the above problems can be solved, and have reached the present invention.

That is, the present invention relates to the following items.

1. A multilayer polyimide film including a layer (A) containing a thermoplastic polyimide (A) having a glass transition temperature of less than 240° C. and a layer (B) containing a heat resistant polyimide (B) having a glass transition temperature of 240° C. or more. And
A multilayer polyimide film, wherein the thermoplastic polyimide (A) is a polyimide having a repeating unit represented by the general formula (1).

[In the formula, X ₁ is a residue of a tetracarboxylic acid selected from the group represented by formula (2). ]

[R _{1 to} R ₂₀ in the formula each independently represent hydrogen, an alkyl group or halogen. ]

2. The glass transition temperature of the said thermoplastic polyimide (A) is less than 200 degreeC, The multilayer polyimide film of said claim|item 1 characterized by the above-mentioned.

3. Item 1 above, wherein the thermoplastic polyimide (A) is a copolymerized polyimide having a repeating unit represented by the general formula (1) and a repeating structure represented by the general formula (3). 2. The multilayer polyimide film according to 2.

[X ₂ in the formula is a residue of a tetracarboxylic acid excluding the general formula (2). ]

4. Item 4. The multilayer polyimide film as described in Item 3, wherein X ₂ in the general formula (3) is a residue of a tetracarboxylic acid selected from the group represented by the general formula (4).

5. formula:
Number of moles of general formula (1)/(number of moles of general formula (1) + number of moles of general formula (3))
5. The multilayer polyimide film as described in 3 or 4 above, wherein the value calculated by is 0.50 or more and less than 1.00.

6. The heat-resistant polyimide (B) has a tetracarboxylic acid residue and a diamine residue that compose the polyimide,
3,3',4,4'-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, and 1,4-hydroquinone dibenzoate-3,3',4,4'-tetracarboxylic dianhydride A tetracarboxylic acid residue based on a tetracarboxylic acid component containing at least one selected from the group consisting of:
p-phenylenediamine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, m-tolidine and 4,4'-diaminobenz Item 6. The multilayer polyimide film according to any one of Items 1 to 5, which is a polyimide comprising a diamine residue based on a diamine component containing at least one component selected from anilide.

7. The multilayer polyimide film has a layer structure in which a thermoplastic polyimide layer (A), a heat-resistant polyimide layer (B), and a thermoplastic polyimide layer (A) are laminated in this order. The multilayer polyimide film according to any one of 1.

8. A method for producing a multilayer polyimide film comprising a thermoplastic polyimide layer (A) and a heat resistant polyimide layer (B),
At least a layer of a thermoplastic polyimide precursor (a) which is a precursor of a thermoplastic polyimide (A) having a repeating unit represented by the general formula (1), and a heat resistant polyimide which is a precursor of a heat resistant polyimide (B). A method for producing a multilayer polyimide film, which comprises producing a multilayer polyimide precursor film having a layer of a precursor (b) by imidizing.

[X ₁ in the formula is a residue of a tetracarboxylic acid selected from the group represented by formula (2). ]

[R _{1 to} R ₂₀ in the formula each independently represent hydrogen, an alkyl group or halogen. ]

9. The layer of the heat-resistant polyimide precursor (b) is coated with the solution of the thermoplastic polyimide precursor (a), or the layer of the thermoplastic polyimide precursor (a) is coated with the heat-resistant polyimide precursor ( 9. The method for producing a multilayer polyimide film according to item 8, wherein the solution of b) is applied to obtain a multilayer polyimide precursor film.

10. Item 9. The method for producing a multilayer polyimide film according to Item 8, wherein the solution of the thermoplastic polyimide precursor (a) and the solution of the heat resistant polyimide precursor (b) are extruded in multiple layers.

11. The glass transition temperature of the polyimide film having the layer (B) containing the heat-resistant polyimide (B) having a glass transition temperature of 240° C. or higher and containing the polyimide having the repeating unit represented by the general formula (1) is less than 240° C. 2. A method for producing a multilayer polyimide film, which comprises applying a solution of a thermoplastic polyimide precursor (a) which is a precursor of the thermoplastic polyimide (A) and imidizing the solution.

[X ₁ in the formula is a residue of a tetracarboxylic acid selected from the group represented by formula (2). ]

[R _{1 to} R ₂₀ in the formula each independently represent hydrogen, an alkyl group or halogen. ]

12. A polyimide film having a layer (A) containing a thermoplastic polyimide (A) having a repeating unit represented by the general formula (1) and a glass transition temperature of less than 240°C, and a heat resistance of 240°C or more. A method for producing a multilayer polyimide film, which comprises bonding a polyimide film having a layer (B) containing a polyimide (B).

[X ₁ in the formula is a residue of a tetracarboxylic acid selected from the group represented by formula (2). ]

[R _{1 to} R ₂₀ in the formula each independently represent hydrogen, an alkyl group or halogen. ]

13. A metal layer, an inorganic layer, or an organic layer on one side or both sides of the multilayer polyimide film according to any one of the above items 1 to 7 or the multilayer polyimide film produced by the production method according to any one of the above items 8 to 12. A polyimide laminate, wherein any one of them is laminated.

14. 1) a step of forming a circuit pattern of a conductor on one side or both sides of a polyimide film (B′) containing a layer (B′) containing a heat resistant polyimide (B′) having a glass transition temperature of 240° C. or higher, and 2) A polyimide film (A′) including at least one layer (A′) containing a polyimide film (B′) having this circuit pattern formed thereon and a thermoplastic polyimide (A′) having a glass transition temperature of less than 240° C. ) And a heat-pressing process at a temperature of 240° C. or lower, and a method of manufacturing a flexible printed circuit or a coreless multilayer circuit.

15. 15. The method for producing a flexible printed circuit or coreless multilayer circuit according to item 14, wherein the thermoplastic polyimide (A') is the thermoplastic polyimide (A) defined in item 1.

16. Item 16. The method for producing a flexible printed circuit or coreless multilayer circuit according to Item 14 or 15, wherein the thermoplastic polyimide (A') is a copolymerized polyimide defined in Item 3 above.

17. The flexible printed circuit or the coreless multilayer circuit according to any one of Items 14 to 16, wherein the heat resistant polyimide (B′) is the heat resistant polyimide (B) defined in Item 6. Manufacturing method.

18. A copolymerized polyimide having a repeating unit represented by the general formula (1) and a repeating structure represented by the general formula (3), wherein the number of moles of the general formula (1)/[the number of moles of the general formula (1) + The number of moles of the general formula (3)] is 0.50 or more and less than 1.00, a copolymerized polyimide.

[In the formula, X ₁ is a tetracarboxylic acid residue selected from the group represented by the general formula (2), and X ₂ is a tetracarboxylic acid residue other than the group represented by the general formula (2). .. ]

[R _{1 to} R ₂₀ in the formula each independently represent hydrogen, an alkyl group or halogen. ]

19. 19. The copolyimide according to item 18, wherein X ₂ is a residue of a tetracarboxylic acid selected from the group represented by formula (4).

20. A copolymerized polyimide having a unit structure represented by the general formula (1) and a unit structure represented by the general formula (3), wherein the number of moles of the general formula (1)/[the number of moles of the general formula (1) + The number of moles of the general formula (3)] is 0.72 to 0.99, the copolymerized polyimide according to the above item 18 or 19.

21. 21. The copolymerized polyimide according to any one of items 18 to 20, wherein the weight average molecular weight determined by GPC is 5,000 to 1,000,000.

22. Any one of the above items 18 to 21, characterized in that the glass transition temperature obtained from tan δ of the dynamic viscoelasticity measurement measured with a film having a thickness of 5 to 150 μm made of a copolymerized polyimide is less than 240° C. The copolymerized polyimide described in 1.

23. The temperature at which the storage elastic modulus is 5×10 ⁶ Pa or less in the dynamic viscoelasticity measurement measured with a film having a thickness of 5 to 150 μm made of a copolymerized polyimide is 210° C. or less, and the above-mentioned item 18 23. The copolymerized polyimide according to any one of 22 to 22.

24. Any of the above items 18 to 23, characterized in that the storage elastic modulus at 200° C. in the dynamic viscoelasticity measurement measured with a film having a thickness of 5 to 150 μm made of a copolymerized polyimide is 6×10 ⁶ Pa or less. The copolyimide according to item 1.

25. The 1% weight loss temperature determined by thermogravimetric analysis (TGA) is 400° C. or higher, and the copolyimide according to any one of items 18 to 24 above.

26. 26. The copolymerized polyimide according to any one of Items 18 to 25, which has a relative dielectric constant of 3.4 or less and a dielectric loss tangent of 0.010 or less at any frequency of 1 kHz to 10 GHz.

27. The number of all tetracarboxylic acid residues contained in the copolymerized polyimide is 0.5 to 10% in excess of the number of all diamine residues, in any one of the above items 18 to 26. The copolymerized polyimide described.

28. Item 28. A heat-resistant adhesive comprising the copolymerized polyimide of any one of Items 18 to 27.

29. Item 28. A heat resistant adhesive film comprising the copolymerized polyimide according to any one of Items 18 to 27.

30. A metal foil with an adhesive, comprising an adhesive layer containing the copolymerized polyimide according to any one of the above items 18 to 27.

31. A resin film with an adhesive, comprising an adhesive layer containing the copolymerized polyimide according to any one of the above items 18 to 27.

32. A polyimide laminate in which any one of an inorganic layer, an organic layer or a metal layer and an adhesive layer containing the copolymerized polyimide according to any one of items 18 to 27 are laminated.

33. 28. An electronic circuit using the insulating layer containing the copolymerized polyimide according to any one of items 18 to 27.

34. A method for producing a copolymerized polyimide laminate, comprising a step of casting or coating a copolymerized polyimide precursor solution on any one of an inorganic layer, an organic layer or a metal layer, and heat-treating,
The copolymerized polyimide is a copolymerized polyimide having a repeating unit represented by the general formula (1) and a repeating structure represented by the general formula (3), wherein the number of moles of the general formula (1)/[the general formula The number of moles of (1) + the number of moles of the general formula (3)] is 0.50 or more and less than 1.00, and a method for producing a copolymerized polyimide laminate.

[In the formula, X ₁ is a tetracarboxylic acid residue selected from the group represented by the general formula (2), and X ₂ is a tetracarboxylic acid residue other than the group represented by the general formula (2). .. ]

[In the formula, R _{1 to} R ₂₀ each independently represent hydrogen, an alkyl group, or halogen. ]

35. A method for producing a heat-resistant adhesive film, which is obtained by peeling one layer out of the inorganic layer, the organic layer or the metal layer from the copolymerized polyimide laminate obtained by the method according to Item 34.

36. The copolymerized polyimide laminate obtained by the method according to the above item 34 or the heat resistant adhesive film obtained by the method according to the above item 35 is further laminated with an inorganic layer, an organic layer or a metal layer, and the temperature is kept at 240°C or lower. A method for producing a multilayer polyimide laminate obtained by heating and laminating.

According to the present invention, a new multilayer polyimide film, which can be easily obtained by a conventional polyimide film manufacturing method, can be bonded at low temperature in a short time, and has high heat resistance, high adhesive strength and low dielectric properties, It is possible to provide a method for producing a film and a polyimide metal laminate using the method.

According to another aspect of the present invention, it is possible to provide a new copolymerized polyimide having high heat resistance, capable of being bonded even at a relatively low temperature, and having high adhesive strength. Further, in another aspect of the present invention, a method for easily producing the polyimide, a heat resistant adhesive using the same, and the like are provided. The copolymerized polyimide of the present invention also has an effect of low dielectric property.

It is an electron microscope photograph of the cross section of the electronic circuit created in Example A13. It is a graph which shows the result of the reliability test of the electronic circuit produced in Example A13 and a comparative example. It is a graph which shows the viscoelastic property of copolymerization polyimide (Example B1). It is a graph which shows the viscoelastic property of the conventional polyimide (Comparative Example B1). It is a graph which shows the result of the peel strength test of the copper foil with an adhesive produced in Example B12 and a comparative example.

In the present specification, the layer (A) containing the thermoplastic polyimide (A) and the layer (B) containing the heat-resistant polyimide (B) are respectively referred to as a thermoplastic polyimide layer (A) and a heat-resistant polyimide for simplification. It may be referred to as a layer (B). Similarly, for simplicity, the layer (A') containing the thermoplastic polyimide (A') and the layer (B') containing the heat-resistant polyimide (B') are each a thermoplastic polyimide layer (A'), It may be called a heat resistant polyimide layer (B').

The thermoplastic polyimide layer (A) contains the thermoplastic polyimide (A) based on the resin component, preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 98% by mass or more (at 100% by mass). It may be included). The heat-resistant polyimide layer (B) contains the heat-resistant polyimide (B) based on the resin component, preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 98% by mass or more (100% by mass). May be included).

Further, the residue of tetracarboxylic acid (or tetracarboxylic acid residue) means a tetravalent group obtained by removing four carboxyl groups (—COOH) from tetracarboxylic acid. The diamine residue (or diamine residue) means a divalent group obtained by removing _two amino groups (—NH ₂ ) from diamine. The tetracarboxylic acid component means a carboxylic acid compound such as tetracarboxylic dianhydride or tetracarboxylic acid that is a raw material of polyimide, and the diamine component means a diamine compound that is a raw material of polyimide.

When a tetracarboxylic acid component and a diamine component are reacted in a predetermined process to synthesize a polyimide, a polyimide having a tetracarboxylic acid residue and a diamine residue derived from a raw material compound is obtained. In the present specification, when specifying the chemical structure of a polyamic acid that is a polyimide or its precursor, instead of directly showing the structure by a chemical formula, by explaining the tetracarboxylic acid component and the diamine component, May be used as an explanation.

Further, in the present specification, the term "thermoplasticity" is used to represent a property having "heat fusion property" and "thermocompression bondability".

The present invention, when roughly classified, relates to an aspect relating to a multilayer polyimide film and an aspect relating to this multilayer polyimide film and a copolymerized polyimide suitable for other uses. First, the multilayer polyimide film and its application will be described, and then the copolymerized polyimide and its application will be described.

<<Multi-layer polyimide film>>
First, the multilayer polyimide film will be described.

The multilayer polyimide film of the present invention comprises a layer (A) containing a thermoplastic polyimide (A) having a glass transition temperature of less than 240° C. and a layer containing a heat resistant polyimide (B) having a glass transition temperature of 240° C. or more ( A multilayer polyimide film comprising B) and
The thermoplastic polyimide layer (A) is characterized by being a polyimide having a repeating unit represented by the general formula (1).

[X ₁ in the formula is a residue of a tetracarboxylic acid selected from the group represented by formula (2). ]

[R _{1 to} R ₂₀ in the formula each independently represent hydrogen, an alkyl group or halogen. ]

Although not particularly limited, the "multilayer polyimide film" here is composed of at least a layer (A) and a layer (B) having different compositions, and the components have clear interfaces between layers. It may be included and separated, or may have a concentration distribution in the film thickness direction (gradient composition). The thermoplastic polyimide here means a polyimide having a glass transition temperature of less than 240°C, and the heat resistant polyimide layer means a polyimide having a glass transition temperature of 240°C or higher.

The tetracarboxylic acid residue having two ether bonds represented by the general formula (2) is not particularly limited, but a tetracarboxylic acid residue containing a bisphenol skeleton represented by the following formula (5) is present. Group, a tetracarboxylic acid residue containing a biphenol skeleton represented by formula (6), a hydroquinone represented by formula (7), or a tetracarboxylic acid residue containing a resorcinol skeleton. Further, since it has excellent heat resistance, a tetracarboxylic acid residue containing a bisphenol skeleton represented by the formula (5) is more preferable, and since the dielectric loss is small, the tetracarboxylic acid residue represented by the following formula (a) is Particularly preferred.

The thermoplastic polyimide (A) (the same applies to the thermoplastic polyimide layer (A)) is not particularly limited, but from the peak of tan δ in the dynamic viscoelasticity measurement measured with a film having a thickness of 5 to 150 μm. The glass transition temperature obtained is less than 240°C, preferably less than 205°C, more preferably less than 200°C, even more preferably 150 to 190°C, particularly preferably 150 to 180°C. The glass transition temperature here is, for example, using a film having only a thermoplastic polyimide layer or a multilayer polyimide film, and dynamic viscoelasticity measurement (DMS), thermomechanical analysis (TMA), differential scanning calorimetry (DSC), Any glass transition temperature obtained by a differential thermal analysis (DTA) and using known conditions and analysis methods may be used. Within this range, it is possible to bond at a relatively low press temperature of 240° C. or less, which is preferable.

The thermoplastic polyimide (A) (the same applies to the thermoplastic polyimide layer (A)) is not particularly limited, but has a storage elastic modulus in dynamic viscoelasticity measurement measured with a film having a thickness of 5 to 150 μm. The temperature at which it becomes 5×10 ⁶ Pa or lower is preferably 210° C. or lower, more preferably 100 to 200° C., further preferably 150 to 195° C., and particularly preferably 170 to 190° C. The temperature at which the storage elastic modulus is 10 ⁶ Pa or lower is preferably 280° C. or lower, more preferably 100 to 250° C., further preferably 150 to 230° C., and particularly preferably 170 to 220° C. The temperature at which the storage elastic modulus is 5×10 ⁵ Pa or lower is preferably 300° C. or lower, more preferably 100 to 280° C., further preferably 150 to 260° C., and particularly preferably 170 to 240° C. Furthermore, the temperature at which the storage elastic modulus is 10 ⁵ Pa or lower is preferably 350° C. or lower, more preferably 100 to 300° C., further preferably 150 to 280° C., and particularly preferably 170 to 260° C. Within this range, it is possible to bond at a relatively low pressing temperature of 240° C. or less, which is preferable.

The thermoplastic polyimide (A) (the same applies to the thermoplastic polyimide layer (A)) is not particularly limited, but at 200° C. in dynamic viscoelasticity measurement measured with a film having a thickness of 5 to 150 μm. The storage elastic modulus is preferably 6×10 ⁶ Pa or less, more preferably 1×10 ^{5 to} 5×10 ⁶ Pa, and particularly preferably 5×10 ⁵ to 4×10 ⁶ Pa. The storage elastic modulus at 210° C. is preferably 5×10 ⁶ Pa or less, more preferably 0.1×10 ^{5 to} 4.5×10 ⁶ Pa, and particularly preferably 1×10 ^{5 to} 3×10 ⁶ Pa. is there. The storage elastic modulus at 220° C. is preferably 4×10 ⁶ Pa or less, more preferably 0.1×10 ⁵ to 2×10 ⁶ Pa, and particularly preferably 1×10 ⁵ to 1×10 ⁶ Pa. Within this range, it is possible to bond at a relatively low pressing temperature of 240° C. or less, which is preferable.

The thermoplastic polyimide (A) (the same applies to the thermoplastic polyimide layer (A)) is not limited, but since it has heat resistance that enables simultaneous production with the heat resistant polyimide film layer, The 1% weight loss temperature determined by analysis (TGA) is preferably 400° C. or higher, more preferably 450° C. or higher, and particularly preferably 460° C. or higher. Although not particularly limited, the TGA was measured in a nitrogen stream at a temperature rising rate of 10° C./min from 25° C. to 600° C., and the 1% weight loss temperature obtained from the obtained weight curve was measured. It can be suitably adopted.

The multilayer polyimide film of the present invention is not particularly limited, and is a multilayer polyimide film including a layer (A) containing a thermoplastic polyimide (A) and a layer (B) containing a heat resistant polyimide (B). ,
The thermoplastic polyimide (A) is preferably a copolymerized polyimide having a repeating unit represented by the general formula (1) and a repeating structure represented by the general formula (3).

[X ₂ in the formula is a residue of a tetracarboxylic acid excluding the general formula (2). ]

Since this copolymerized polyimide has uses other than the use of the multilayer polyimide film of this embodiment, the details thereof will be described in another section.

Further, the thermoplastic polyimide (A) is not particularly limited, but is a polyimide obtained by reacting a tetracarboxylic acid component and a diamine component, and the total number of moles of the tetracarboxylic acid component is the diamine component. It is preferably 0.5 to 10 mol% excess, more preferably 1 to 7 mol% excess, and particularly preferably 1 to 5 mol% excess from the total number of moles. Within this range, the adhesiveness at low temperature and the heat resistance can both be achieved, which is preferable. The obtained polyimide contains a tetracarboxylic acid residue based on the tetracarboxylic acid component used as a raw material and a diamine residue based on the diamine component at a ratio corresponding to the charged molar ratio.

The weight average molecular weight of the thermoplastic polyimide (A) is preferably 5,000 to 1,000,000 as determined by GPC, and is 10,000 to 500,000 because of excellent adhesiveness. Is more preferable, and since it is excellent in heat resistance, it is particularly preferable that it is 50,000 to 500,000.

The thermoplastic polyimide (A) is not limited, but since it has heat resistance that enables production at the same time as the heat resistant polyimide film layer, the 1% weight loss temperature determined by thermogravimetric analysis (TGA) is The temperature is preferably 400°C or higher, more preferably 450°C or higher, and particularly preferably 460°C or higher. Although not particularly limited, the TGA was measured in a nitrogen stream at a temperature rising rate of 10° C./min from 25° C. to 600° C., and the 1% weight loss temperature obtained from the obtained weight curve was measured. It can be suitably adopted.

The thermoplastic polyimide (A) is not limited, but since it has a low dielectric loss, it is preferable that the water absorption rate obtained by immersion in water according to ASTM D570 23° C. for 24 hours is 1.4% or less. It is preferably 1.0%, particularly preferably 0.8% or less.

Although the thermoplastic polyimide (A) of the present invention is not limited, the relative dielectric constant at 1 kHz to 10 GHz is preferably 3.4 or less, more preferably 3.2 or less, and particularly preferably 3.1 or less. The dielectric loss tangent is preferably 0.010 or less, more preferably 0.005 or less, and particularly preferably 0.003 or less. Within this range, it can be suitably used as an insulating material or an adhesive for high frequency circuits. Although not particularly limited, the relative permittivity and the dielectric loss tangent measured in the normal state (C-96/20/65) based on JIS C6481 can be preferably used. Known measuring devices and methods can be preferably used.

The thermoplastic polyimide layer (A) includes, as components other than the thermoplastic polyimide (A), thermosetting resins such as epoxy resin, phenol resin, acrylic resin, cyanate resin, and BT resin, inorganic fillers, pigments, dyes, and oxidation. An inhibitor, a plasticizer, a solvent, etc. can be added suitably. However, in the present invention, the thermoplastic polyimide layer (A) can be bonded at low temperature in a short time even if it does not contain a substance such as a plasticizer or a solvent that plasticizes the layer (thermofusible property, Since it has thermocompression bonding property), it is preferable not to include additives such as a plasticizer and a solvent. From the viewpoint of durability and mechanical properties, it is also preferable to use an all-polyimide composition containing no thermosetting resin or thermoplastic resin.

The heat-resistant polyimide (B) is not particularly limited as long as it has a glass transition temperature of 240° C. or higher, but is preferably 280° C. or higher, more preferably 300° C. or higher, and particularly preferably 320° C. or higher. The heat-resistant polyimide layer (B) may have a multilayer structure. In the case of the heat-resistant polyimide layer (B) having a multilayer structure, the glass transition temperature of the polyimide layer having the highest glass transition temperature is set. It can be preferably used as the glass transition temperature of the heat resistant polyimide layer (B).

The heat-resistant polyimide (B) is not particularly limited, but for example,
From 3,3',4,4'-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride and 1,4-hydroquinone dibenzoate-3,3',4,4'-tetracarboxylic dianhydride An acid component containing at least one selected component, preferably at least 70 mol% or more, more preferably 80 mol% or more, more preferably 90 mol% or more tetracarboxylic acid component containing these acid components,
A diamine component containing at least one component selected from p-phenylenediamine, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, m-tolidine and 4,4′-diaminobenzanilide, preferably these diamines. A polyimide obtained from a diamine component containing at least 70 mol% or more, more preferably 80 mol% or more, and even more preferably 90 mol% or more is included. Regarding the tetracarboxylic acid residue and the diamine residue constituting the obtained polyimide, the tetracarboxylic acid residue preferably contains the residue based on the tetracarboxylic acid compound in the ratio described above, and the diamine residue is the diamine. The residues based on the compounds are preferably contained in the abovementioned proportions.

Examples of combinations of the tetracarboxylic acid component and the diamine component that can obtain the heat-resistant polyimide include the following.
(1) A combination containing 3,3′,4,4′-biphenyltetracarboxylic dianhydride (s-BPDA), p-phenylenediamine (PPD), and optionally 4,4-diaminodiphenyl ether (DADE) .. In this case, PPD/DADE (molar ratio) is preferably 100/0 to 85/15.
(2) 3,3′,4,4′-biphenyltetracarboxylic dianhydride (s-BPDA) and pyromellitic dianhydride (PMDA), p-phenylenediamine (PPD), and optionally 4, A combination comprising 4-diaminodiphenyl ether (DADE). In this case, the s-BPDA/PMDA (molar ratio) is preferably 0/100 to 90/10. When PPD and DADE are used in combination, the PPD/DADE (molar ratio) is preferably 90/10 to 10/90, for example.
(3) A combination of pyromellitic dianhydride (PMDA), p-phenylenediamine (PPD) and 4,4-diaminodiphenyl ether (DADE). In this case, the DADE/PPD (molar ratio) is preferably 90/10 to 10/90.
(4) 3,3′,4,4′-biphenyltetracarboxylic dianhydride (s-BPDA) and p-phenylenediamine (PPD) as main components (50 mol% or more in 100 mol% in total) What you get.

In the above (1) to (3), part or all of 4,4-diaminodiphenyl ether (DADE) may be replaced with 3,4′-diaminodiphenyl ether or 2,2-bis[4-(4- It can also be replaced with aminophenoxy)phenyl]propane. In addition, in the above (1) to (4), part or all of 3,3′,4,4′-biphenyltetracarboxylic dianhydride may be replaced with 3,3′,4,4′-, depending on the purpose. It can also be replaced with benzophenone tetracarboxylic dianhydride.

The combination of (1) above is preferable because it has excellent heat resistance. Further, a tetracarboxylic acid containing 3,3′,4,4′-biphenyltetracarboxylic dianhydride as a main component (for example, 70 mol% or more, preferably 80 mol% or more, more preferably 90 mol% or more). Use of a heat resistant polyimide obtained from a dianhydride component and a diamine component containing para-phenylenediamine as a main component (for example, 70 mol% or more, preferably 80 mol% or more, more preferably 90 mol% or more). This makes it possible to obtain a thermoplastic polyimide film having a low coefficient of linear expansion, a high elastic modulus, and excellent dimensional stability.

The tetracarboxylic acid component that can obtain the heat-resistant polyimide (B) is, in addition to the above-mentioned acid component, another tetracarboxylic dianhydride component and/or another diamine within a range that does not impair the intended properties. The components can be used together. Other tetracarboxylic dianhydride components include 3,3′,4,4′-benzophenone tetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, bis(3,4 -Dicarboxyphenyl) sulfide dianhydride, bis(3,4-dicarboxyphenyl) sulfone dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, 2,2-bis(3,4- Dicarboxyphenyl)propane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride, 2,2-bis[( 3,4-dicarboxyphenoxy)phenyl]propane dianhydride and the like. Other diamine components include m-phenylenediamine, 2,4-toluenediamine, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'. -Diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,4'-diaminobenzophenone, 3,3 '-Diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 2,2-di(3-aminophenyl)propane, 2,2-di(4-aminophenyl)propane, 1,3 -Bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene, etc. Examples thereof include bis(aminophenoxy)benzenes, 2,2-bis[4-(4-aminophenoxy)phenyl]propane and 4,4′-bis(4-aminophenoxy)biphenyl.

The heat-resistant polyimide layer (B) is substantially composed of the heat-resistant polyimide (B) from the viewpoint of heat resistance and mechanical properties, that is, the resin component is substantially only the heat-resistant polyimide (B). Is preferred.

The multilayer polyimide film of the present invention is not particularly limited, but the thickness of the heat resistant polyimide layer (B) is preferably 3 to 125 μm, more preferably 5 to 100 μm, and 5 to 75 μm. It is particularly preferable that The thickness of the thermoplastic polyimide layer (A) is preferably 0.1 to 100 μm, more preferably 0.5 to 50 μm, and particularly preferably 1 to 25 μm.

[Method for producing multilayer polyimide film]
Next, as an example of a method for producing a multilayer polyimide film containing a thermoplastic polyimide layer (A) of the present invention, a multilayer polyimide film having a thermoplastic polyimide layer (A) on one side or both sides of a heat resistant polyimide layer (B) is prepared. The manufacturing method will be described.

[Production method of multilayer polyimide film by coating method]
A multilayer polyimide film is a polyimide precursor that provides a thermoplastic polyimide layer (A) on one or both sides of a self-supporting film obtained from a solution (polyamic acid solution) of a polyimide precursor (b) that provides a heat-resistant polyimide layer (B). It can be obtained by applying the solution of the body (a) (polyamic acid solution) and heating and drying the obtained multilayer self-supporting film to perform imidization. Here, the polyimide precursor (a) solution that gives the thermoplastic polyimide layer (A) is a tetracarboxylic acid component containing at least a tetracarboxylic acid compound (preferably a dianhydride) that gives the general formula (1). And a diamine component are reacted with each other. In the case of copolymerized polyimide, the tetracarboxylic acid component further contains a tetracarboxylic acid compound (tetracarboxylic dianhydride, tetracarboxylic acid, etc.) that gives the general formula (3). The synthesis of the copolymerized polyimide will be described later.

Further, in this manufacturing method, the polyimide precursor (a) solution which gives the thermoplastic polyimide layer (A) and the polyimide precursor (b) solution which gives the heat resistant polyimide layer (B) may be replaced. That is, the polyimide precursor (b) solution is applied to one or both sides of the self-supporting film obtained from the polyimide precursor (a) solution, and the resulting multilayer self-supporting film is heated and dried to obtain an imide. You may convert.

The self-supporting film obtained from the polyimide precursor (b) solution that gives the heat-resistant polyimide layer (B) has a tetracarboxylic acid component and a diamine component in substantially equimolar amounts, or with a slight excess of either component. Then, a polyamic acid solution [polyimide precursor (b) solution] obtained by reacting in an organic solvent is cast on a support, and this can be obtained by heating and drying.

On the other hand, the polyimide precursor (a) solution that gives the thermoplastic polyimide layer (A) is also used in an organic solvent in which the tetracarboxylic acid component and the diamine component are substantially equimolar, or one component is slightly excessive. It is obtained by reacting with.

As an organic solvent for producing a polyimide precursor solution, N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-diethylacetamide, N,N-dimethylformamide, N,N-diethylformamide, Examples thereof include amides such as hexamethylphosphoramide, sulfoxides such as dimethyl sulfoxide and diethyl sulfoxide, and sulfones such as dimethyl sulfone and diethyl sulfone. These solvents may be used alone or as a mixture.

The concentration of all the monomers in the organic solvent when carrying out the polymerization reaction of the polyimide precursor can be appropriately selected according to the purpose of use. For example, in the polyimide precursor (a) solution, the concentration of all the monomers in the organic solvent is preferably 1 to 50% by mass, particularly preferably 5 to 40%, and the polyimide precursor (b) solution is The concentration of all the monomers in the organic solvent is preferably 5 to 40% by mass, more preferably 6 to 35% by mass, and particularly preferably 10 to 30% by mass.

As an example of a production example of the polyimide precursor (a) solution and the polyimide precursor (b) solution, for example, a tetracarboxylic acid component and a diamine component are substantially equimolar, or either component (acid component or diamine). Components) in a slight excess and mixed, and reacted at a reaction temperature of 100° C. or lower, preferably 80° C. or lower (usually 0° C. or higher, preferably 15° C. or higher) for about 0.2 to 60 hours to give a polyamic acid (polyimide). A precursor) solution can be obtained.

The solution viscosity of the polyimide precursor (a) solution and the polyimide precursor (b) solution can be appropriately selected according to the purpose of use (coating, casting, etc.). For example, when the polyimide precursor (a) solution and the polyimide precursor (b) solution are used for casting, from the viewpoint of workability of handling the polyimide precursor solution, the rotational viscosity measured at 30° C. is about 100. ˜5000 poise is preferable, 500-4000 poise is more preferable, 1000-3000 poise is particularly preferable. Further, when using the polyimide precursor (a) solution and the polyimide precursor (b) solution for coating, from the viewpoint of workability of handling the polyimide precursor solution, the rotational viscosity measured at 30° C. is 1 to 100 centipoise. Is more preferable, 3 to 50 centipoise is more preferable, and 5 to 20 centipoise is particularly preferable. Therefore, it is desirable to carry out the above-mentioned polymerization reaction to such an extent that the generated polyamic acid (polyimide precursor) exhibits the above viscosity.

The self-supporting film of the polyimide precursor (b) solution to be the heat-resistant polyimide layer (B) may be prepared, for example, by adding the polyimide precursor (b) solution to a suitable support (for example, a roll made of metal, ceramic, plastic, or It is cast on the surface of a metal belt or the like) to form a film having a uniform thickness, and then heated to 50 to 210°C, particularly 60 to 200°C using a heat source such as hot air or infrared rays. It can be obtained by gradually removing the solvent and drying until it becomes self-supporting (for example, to the extent that it can be peeled from the support).

In the present invention, the polyimide precursor (a) solution that gives the thermoplastic polyimide layer (A) is applied to one or both sides of the self-supporting film of the polyimide precursor (b) solution thus obtained. .. The polyimide precursor (a) solution may be applied to the self-supporting film peeled from the support, or may be applied to the self-supporting film on the support before peeling from the support.

The polyimide precursor (a) solution can be applied to a self-supporting film of the polyimide precursor (b) solution, for example, a gravure coating method, a spin coating method, a silk screen method, a dip coating method, a spray coating method. A known coating method such as a bar coating method, a knife coating method, a roll coating method, a blade coating method or a die coating method can be used.

In the present invention, it is preferable to uniformly coat the polyimide precursor (a) solution with one or both surfaces of the self-supporting film of the polyimide precursor (b) solution. Therefore, the self-supporting film preferably has a surface on which the polyimide precursor (a) solution can be uniformly applied.

The self-supporting film of the polyimide precursor (b) solution preferably has a heating loss in the range of 20 to 40% by mass and an imidization ratio in the range of 8 to 40%. If the weight loss upon heating and the imidization ratio are within the above ranges, the mechanical properties of the self-supporting film will be sufficient, and the polyimide precursor (a) solution will be easily applied onto the upper surface of the self-supporting film, resulting in imidization. Foaming, cracks, crazes, cracks, cracks and the like are not observed in the polyimide film obtained later, and the adhesive strength between the heat-resistant polyimide layer and the thermoplastic polyimide layer is sufficient.

The heating weight loss of the self-supporting film is a value obtained by drying the film to be measured at 400° C. for 30 minutes and using the weight before drying (W1) and the weight after drying (W2) according to the following equation. ..
Heating loss (mass %)={(W1-W2)/W1}×100

If necessary, fine inorganic or organic fillers (additives) can be added to the thermoplastic polyimide layer (A) and the heat resistant polyimide layer (B). Examples of the inorganic additive include particulate or flat inorganic fillers such as particulate titanium dioxide powder, silicon dioxide (silica) powder, magnesium oxide powder, aluminum oxide (alumina) powder, zinc oxide powder. Inorganic oxide powder such as, fine particle silicon nitride powder, inorganic nitride powder such as titanium nitride powder, inorganic carbide powder such as silicon carbide powder, fine particle calcium carbonate powder, calcium sulfate powder, inorganic such as barium sulfate powder Mention may be made of salt powder. Examples of the organic additive include polyimide particles and thermosetting resin particles. You may use these additives in combination of 2 or more type. The amount and shape (size, aspect ratio) of the additive used are preferably selected according to the purpose of use. Moreover, in order to uniformly disperse these additives, a means known per se can be applied.

After coating the polyimide precursor (a) solution on the self-supporting film of the polyimide precursor (b) solution, this is then heated and imidized to obtain a multilayer polyimide film. The maximum heating temperature of the heat treatment for imidization is preferably 300°C to 600°C, more preferably 320 to 500°C, particularly preferably 340 to 500°C.

It is preferable to perform the heat treatment for imidization stepwise. First, after the first heat treatment at a temperature of 150° C. to 200° C. for 1 minute to 60 minutes, then at a temperature of 200° C. or higher and lower than 300° C. for 1 minute to It is desirable to perform the second heat treatment for 60 minutes, and then perform the third heat treatment at the maximum heating temperature of 300°C to 600°C, preferably 320 to 550°C, more preferably 340 to 500°C for 1 minute to 30 minutes. This heat treatment can be performed using a known device such as a hot air stove or an infrared heating furnace.

Further, this heat treatment is preferably performed by fixing a self-supporting film of the polyimide precursor solution (b) coated with the polyimide precursor (a) solution with a pin tenter, a clip or the like.

The polyimide precursor (a) solution and/or the polyimide precursor (b) solution is a phosphorus-based stabilizer such as triphenyl phosphite or triphosphate for the purpose of limiting gelation of the polyamic acid (polyimide precursor). Phenyl and the like can be added in the range of 0.01 to 1% with respect to the solid content (polymer) concentration during the polyamic acid polymerization.

A basic organic compound can be added to the polyimide precursor (a) solution and/or the polyimide precursor (b) solution for the purpose of promoting imidization. For example, 0.0005 to 0.1 of imidazole, 2-methylimidazole, 1,2-dimethylimidazole, 2-phenylimidazole, benzimidazole, isoquinoline, substituted pyridine, etc., relative to 100 parts by mass of polyamic acid (polyimide precursor). It may be added in an amount of 0.001 to 0.02 parts by mass. These can be used to avoid insufficient imidization to form polyimide films at relatively low temperatures.

[Method for producing multilayer polyimide film by coextrusion-casting film formation method]
The multilayer polyimide film of the present invention is obtained by a coextrusion-casting film forming method (also simply referred to as a coextrusion method), a solution of a heat-resistant polyimide (B) in a polyimide precursor (b) (hereinafter, a dope solution (b)). , A polyamic acid solution (also referred to as “b”) and a polyimide precursor (a) solution of the thermoplastic polyimide (A) (hereinafter, also referred to as a dope solution (a) and a polyamic acid solution (a)) are laminated and dried, It can also be manufactured by a method of imidizing to obtain a multilayer polyimide film. As the coextrusion method, for example, the method described in JP-A-3-180343 (Japanese Patent Publication No. 7-102661) can be used.

More specifically, this co-extrusion method uses an extruder having two or more extrusion molding dies, and the dope of the heat resistant polyimide layer and the dope of the thermoplastic polyimide layer from the discharge port of the die. The liquid and the liquid are continuously extruded onto a thin, smooth support having at least two layers. Then, the thin film on the support is dried to form a multi-layer self-supporting film, then the multi-layer self-supporting film is peeled off from the support, and finally the multi-layer self-supporting film is heat treated. Is to do. At this time, the drying temperature of the thin film cast material is 140° C. or higher, preferably 145° C. or higher. This improves the peel strength of the polyimide metal laminate described below.

The two-layer extrusion molding die has, for example, a dope solution supply port, a dope solution passage is formed from each of the supply ports toward each manifold, and a channel at the bottom of the manifold is formed. A structure in which the passage (lip portion) of the dope solution after merging at the merging point communicates with the slit-shaped discharge port, and the dope liquid is discharged in a thin film form on the support from this discharge port. (Multi-manifold type two-layer die) can be mentioned. The gap of the lip portion can be adjusted by a lip adjusting bolt. In addition, at the bottom of each manifold (a portion near the confluence), the distance between the voids of the flow passage is adjusted by each choke bar. Each of the above manifolds preferably has a hanger coat type shape. Further, the two-layer extrusion molding die has supply ports for the respective dope liquids on the left and right of the upper part of the die, and the passages for the dope liquids are immediately joined at the joining points provided with the partition plates. A dope solution flow path communicates with the manifold from the junction, and a dope solution passage (lip portion) at the bottom of the manifold communicates with the slit-shaped discharge port. It may have a structure (feed block type two-layer die or single manifold type two-layer die) in which the dope liquid is discharged in a groove film shape from the discharge port onto the support. In addition, regarding the form such as the drying condition and the heating condition after the operation of continuously extruding onto the support in the coextrusion-casting film forming method, the content described in the above-mentioned “method for producing a multilayer polyimide film by a coating method” is applied as it is. it can.

In addition to the above-mentioned two-layer extrusion, by using an extrusion molding die having three or more layers, a multilayer extruded polyimide film can be produced by a molding method similar to that of the two-layer extrusion molding. That is, by using the dope liquid for the heat-resistant polyimide layer and the dope liquid for the thermoplastic polyimide layer, a two-layer multilayer polyimide film can be obtained. Further, in the case of the layer structure of the dope liquid (a) of the thermoplastic polyimide layer-the dope liquid (b) of the heat-resistant polyimide layer-the dope liquid (a) of the thermoplastic polyimide layer, a three-layer polyimide film is used. You can also get it.

[Manufacturing method of multilayer polyimide film by laminating]
The multilayer polyimide film of the present invention can also be produced by bonding a polyimide film having the thermoplastic polyimide layer (A) and a polyimide film having the heat resistant polyimide layer (B). In this method, a publicly known method is used to obtain a polyimide film having the thermoplastic polyimide layer (A) and a polyimide film having the heat-resistant polyimide layer (B), and then directly apply them (other adhesives are used). A multilayer polyimide film can be suitably obtained by laminating (without using). The bonding method is not particularly limited, but hot pressing, vacuum hot pressing, roll laminating, RTM molding, vacuum bag molding and the like can be preferably used. In the method for producing a multi-layer polyimide film by laminating according to the present invention, laminating can be carried out under conditions of relatively low temperature, low pressure and short time. Therefore, the laminating temperature is preferably 150 to 240°C, more preferably 180°C to 220. C, particularly preferably 180 to 200° C., the pressure is preferably 0.01 to 10 MPa, more preferably 0.1 to 5 MPa, particularly preferably 0.5 to 3 MPa, and the pressure bonding time is preferably Is 30 minutes or less, more preferably 10 minutes or less, and particularly preferably 10 seconds to 1 minute.

As the polyimide film having the heat-resistant polyimide layer (B) here, a film obtained by forming the heat-resistant polyimide film composition by a known method or a commercially available polyimide film can be used. Examples of commercially available heat-resistant polyimide films include Upilex (registered trademark) manufactured by Ube Industries, Kapton EN (registered trademark) manufactured by Toray DuPont, and Apical NPI (registered trademark) manufactured by Kaneka Corporation. ..

Further, in order to increase the adhesive strength between the heat-resistant polyimide film and the thermoplastic polyimide film, it is desirable to surface-treat the heat-resistant polyimide film before coating. Examples of the surface treatment method include corona treatment, plasma treatment, alkali treatment, etching treatment, coupling agent treatment, and a combination thereof. For the same reason, a heat-resistant polyimide film having a multilayer structure can also be preferably used.

The multilayer polyimide film obtained by this production method is not particularly limited, but the interlayer adhesive strength between the polyimide film having the thermoplastic polyimide layer (A) and the polyimide film having the heat resistant polyimide layer (B) is The peel strength measured by the method of JIS C6471 is 0.3 kN/m or more, preferably 0.5 kN/m or more, and more preferably 0.7 kN/m or more.

[Other Modifications of Manufacturing Method of Multilayer Polyimide Film]
In addition, the multilayer polyimide film of the present invention is obtained by applying a polyamic acid solution (a) of a thermoplastic polyimide (A) to a heat-resistant polyimide film, heating and drying to imidize the coating layer. You can also get it. As the heat-resistant polyimide film, a film having the above-mentioned heat-resistant polyimide film composition formed by a known method or a commercially available polyimide film can be used. Examples of commercially available heat-resistant polyimide films include Upilex (registered trademark) manufactured by Ube Industries, Kapton EN (registered trademark) manufactured by Toray DuPont, and Apical NPI (registered trademark) manufactured by Kaneka Corporation. .. The amic acid solution (a) of the thermoplastic polyimide (A) to be coated and the drying conditions can be the same as the above-mentioned method for coating the self-supporting film.

Further, in order to increase the adhesive strength between the heat-resistant polyimide film and the thermoplastic polyimide layer (A), it is desirable to surface-treat the heat-resistant polyimide film before coating. Examples of the surface treatment method include corona treatment, plasma treatment, alkali treatment, etching treatment, coupling agent treatment, and a combination thereof. For the same reason, a heat-resistant polyimide film having a multilayer structure can also be preferably used.

The multi-layer polyimide film of the present invention can be easily obtained by a conventional method for producing a polyimide film, can be bonded even at a relatively low temperature, and can achieve high heat resistance, high adhesive strength and low dielectric properties, and thus can be used as a heat resistant electronic material. It can be preferably used as a conductive adhesive. Specifically, coverlays, interphase adhesives for multi-layer boards, bonding sheets for multi-layer boards, embedded resins for component-embedded boards, encapsulation resins, underfills, adhesive layers for copper-clad laminates, adhesive layers for TAB tape, etc. is there.

[Polyimide laminate]
Next, the polyimide laminate of the present invention will be described. The polyimide laminate of the present invention is formed by laminating a metal layer, an inorganic layer or an organic layer on the thermoplastic polyimide layer (A) of the multilayer polyimide film of the present invention. The lamination here may be on both sides or one side, and may be entirely or partially laminated. Moreover, the polyimide laminated body of this invention may laminate the said multilayer polyimide film which has the said thermoplastic polyimide layer on one side or both sides of the outermost layer. Here, the thermoplastic polyimide layer (A) and the metal layer, the inorganic layer, or the organic layer are directly bonded to each other without using another adhesive.

The polyimide laminate of the present invention is obtained by stacking and laminating any one of a metal layer, an inorganic layer (glass layer, ceramic layer, etc.), and an organic layer (resin layer, etc.) on a multilayer polyimide film. The bonding method is not particularly limited, but hot pressing, vacuum hot pressing, roll laminating, RTM molding, vacuum bag molding and the like can be preferably used. Since the multi-layer polyimide film of the present invention has excellent moldability, it can be bonded under conditions of relatively low temperature, low pressure and short time. Therefore, the bonding temperature is preferably 150 to 240°C, more preferably 180°C to 220°C. C, particularly preferably 180 to 200° C., the pressure is preferably 0.01 to 10 MPa, more preferably 0.1 to 5 MPa, particularly preferably 0.5 to 3 MPa, and the pressure bonding time is preferably Is 30 minutes or less, more preferably 10 minutes or less, and particularly preferably 10 seconds to 1 minute.

The metal layer is preferably a metal foil. As the metal foil, various metal foils such as copper, aluminum, gold, and alloy foils of these can be used. Of these, copper foil is preferably used. Specific examples of the copper foil include rolled copper foil and electrolytic copper foil. Further, when laminating metal layers on both sides of the multilayer polyimide film, the same or different metals can be used.

The thickness of the metal foil is not particularly limited, but is preferably 2 to 35 μm, particularly 5 to 18 μm. For the metal foil having a thickness of 5 μm or less, a metal foil with a carrier, for example, a copper foil with an aluminum foil carrier can be used.

In the present invention, a metal layer (metal foil or the like) is laminated on both surfaces of a multilayer polyimide film, and the multilayer polyimide film and the metal layer are thermocompression-bonded to each other, whereby a metal layer is laminated on both surfaces of the multilayer polyimide film. You can get the body. Further, by stacking a metal layer (such as a metal foil) on one surface of the multilayer polyimide film and thermocompressing the thermoplastic polyimide film and the metal layer, a polyimide metal laminate in which the metal layer is laminated on one surface of the multilayer polyimide film is obtained. Obtainable.

Examples of the pressure member include a pair of pressure-bonded metal rolls (the pressure-bonded portion may be made of metal or ceramic sprayed metal), a double belt press, and a hot press, which can be thermocompression-bonded and cooled under pressure. Among them, a hydraulic double belt press is particularly preferable. In addition, a polyimide metal laminate can be easily obtained by roll lamination using a pair of pressure-bonded metal rolls.

In the present invention, the pressurizing member, for example, a metal roll, preferably a double belt press is used, the thermoplastic polyimide film, the metal foil and the reinforcing material are superposed and continuously pressure-bonded under heating. A long polyimide metal laminate can be manufactured.

Further, it is particularly suitable when the thermoplastic polyimide film and the metal foil are used in a rolled state and are continuously supplied to the pressing members, respectively, and the polyimide metal laminate can be obtained in a rolled state.

In the polyimide metal laminate of the present invention, the multilayer polyimide film and the metal foil are firmly laminated. According to the present invention, for example, the peel strength between the polyimide film and the metal foil measured by the method of JIS C6471 is 0.3 kN/m or more, preferably 0.5 kN/m or more, more preferably 0.7 kN/m or more. It is possible to obtain a polyimide metal laminate of Incidentally, in the three-layer thermoplastic polyimide film in which the thermoplastic polyimide layer is laminated on both sides of the heat-resistant polyimide layer, in the polyimide metal laminate in which the metal layer is laminated on the thermoplastic polyimide layer, the peeled state ( The peeling mode) includes a case of peeling at the interface between the heat-resistant polyimide layer and the thermoplastic polyimide film, and a case of peeling at the interface between the thermoplastic polyimide layer and the metal layer. Therefore, the measured peel strength is the peel strength of the surface with weaker adhesive strength. As a method for measuring the peel strength, a known method such as the method of JIS C6471 can be adopted. Specifically, the method described in the examples can be mentioned.

INDUSTRIAL APPLICABILITY The polyimide metal laminate of the present invention has good moldability, and can be directly subjected to drilling, bending, drawing, metal wiring formation and the like. Moreover, the thermoplastic polyimide film of the present invention can be used for thermocompression bonding of an electronic circuit onto a wiring. INDUSTRIAL APPLICABILITY The multilayer polyimide film and the polyimide metal laminate of the present invention can be used as a material for electronic components such as printed wiring boards, flexible printed boards, COFs and TAB tapes, and electronic devices. Further, the thermoplastic polyimide film of the present invention is a sealing material for tab leads of lithium ion batteries, polymer batteries, electric double layer capacitors, etc. using an aluminum laminated film as an outer bag, cover lay for flexible printed circuit boards, ceramic packages and caps. It can be suitably used as an adhesive sheet, such as a bonding material with, which requires reliability at high temperatures.

[Method for manufacturing flexible printed circuit and coreless multilayer circuit]

The method for manufacturing a flexible printed circuit or a coreless multilayer circuit according to the present invention,
1) a step of forming a circuit pattern of a conductor on one side or both sides of a polyimide film (B′) containing a layer (B′) containing a heat resistant polyimide (B′) having a glass transition temperature of 240° C. or higher, and 2) A polyimide film (A′) including at least one layer (A′) containing a polyimide film (B′) having this circuit pattern formed thereon and a thermoplastic polyimide (A′) having a glass transition temperature of less than 240° C. ) And, and the process of thermocompression bonding at a temperature of 240° C. or lower is included.

Note that the flexible printed circuit and the coreless multilayer circuit herein are circuits that do not include glass cloth. Since the flexible printed circuit is excellent in flexibility, it is preferable that there is no abnormality such as cracking or peeling even when bent to a diameter of 1 cm, it is more preferable that the insulating layer does not contain an epoxy resin, and an inorganic component such as a filler is contained. It is more preferably 1% by weight or less. Since the coreless multilayer circuit has excellent transmission characteristics at high frequencies, it is preferable not to include glass cloth, more preferably 1% by weight or less of an inorganic component such as a filler, and particularly preferably not to include an epoxy resin.

In addition, when forming a multilayer, the steps 1) and 2) can be repeated to form a multilayer, and necessary layers are pre-aligned (temporary bonding is performed if necessary), It is also possible to perform thermocompression bonding at once and form a multilayer.

The step 1) will be described in detail below.
The polyimide film (B′) containing the heat-resistant polyimide layer (B′) having a glass transition temperature of 240° C. or higher has dimensions as long as the heat-resistant polyimide layer (B′) having a glass transition temperature of 240° C. or higher is included. Since it has excellent stability, it can be preferably used, but the glass transition temperature is preferably 300° C. or higher, and more preferably 340° C. The coefficient of linear expansion (average coefficient of linear thermal expansion at 25°C to 200°C) is preferably 0 to 40 ppm/K, more preferably 0 to 30 ppm/K, and further preferably 0 to 20 ppm/K. Such a heat-resistant polyimide layer (B') is preferably the above-mentioned heat-resistant polyimide layer (B), and the preferable range is also the same. Further, the polyimide film (B′) may be a single layer of the heat resistant polyimide layer (B′), but other polyimide layers may be formed in addition to the heat resistant polyimide layer (B′), Further, those layers may have a clear interface or may have a graded layer. An example of such a polyimide film is Upilex VT manufactured by Ube Industries, Ltd.

As a method for forming a circuit pattern, a known method can be preferably used. For example, using the above polyimide film, a conductor (copper, etc.) is laminated by a sputtering method, a laminating method, or a direct metallizing method to obtain a flexible copper-clad laminate, and then a circuit pattern is formed by a subtractive method or a semi-additive method. And a method of forming a circuit pattern directly on the polyimide film by a full additive method. In particular, since the flexible printed circuit or the coreless multilayer circuit of the present invention is formed of all-polyimide, it has excellent insulation reliability, and also has excellent fluidity of the thermoplastic polyimide layer (A′). Pitch circuits can be formed, and the line width and the space width are preferably 100 μm or less, more preferably 50 μm or less, further preferably 20 μm or less, and particularly preferably 1 to 10 μm. This range is preferable because long-term insulation reliability can be obtained.

Next, the step 2) will be described in detail below.
If the polyimide film (A′) containing the thermoplastic polyimide layer (A′) having a glass transition temperature of less than 240° C. has a glass transition temperature of less than 240° C. Since it can be thermocompression bonded at 240° C. or lower, it can be preferably used, but the glass transition temperature is preferably 200° C. or lower, more preferably 180° C. or lower. Such a thermoplastic polyimide layer (A') is preferably the above-mentioned thermoplastic polyimide layer (A), and the preferred range is also the same. Further, the polyimide film (A') may be a single layer of the thermoplastic polyimide layer (A'), but other polyimide layer may be formed in addition to the thermoplastic polyimide layer (A'), Further, those layers may have a clear interface or may have a graded layer. Examples of the other polyimide layer include the heat resistant polyimide (B).

Moreover, as a method for laminating the polyimide film (A′) containing the thermoplastic polyimide layer (A′) and the polyimide film (B′) containing the heat-resistant polyimide layer (B′) on which the circuit pattern is formed, heating is performed. Any method may be used as long as it can be pressure-bonded, but for example, a hot press, a hot roll laminate, a hot double belt press, etc. are suitable, and an atmospheric pressure, a reduced pressure, or an inert gas (for example, nitrogen) atmosphere. It is preferably thermocompression bonded underneath. The maximum temperature during thermocompression bonding is 240° C. or lower, preferably 200° C. or lower, more preferably 190° C. or lower, still more preferably 180° C. or lower, because the fluidity during heating of the insulating layer is excellent.

As described above, the thermoplastic polyimide layer (A′) is preferably the above-mentioned thermoplastic polyimide layer (A), and the preferable range is also the same. A copolymerized polyimide having a repeating unit represented by the general formula (1) and a repeating structure represented by the general formula (3) is preferable because it has excellent fluidity during thermocompression bonding. Preferred copolymerized polyimide will be described later.

As described above, the heat-resistant polyimide layer (B′) is preferably the heat-resistant polyimide layer (B), and the preferable range is also the same. Due to its excellent dimensional stability, for example, 3,3′,4,4′-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, and 1,4-hydroquinone dibenzoate-3,3′,4 A tetracarboxylic acid component containing at least one component selected from the group consisting of 4'-tetracarboxylic dianhydride, p-phenylenediamine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether and 2,2- A diamine component containing at least one component selected from bis[4-(4-aminophenoxy)phenyl]propane, m-tolidine and 4,4′-diaminobenzanilide is preferable, and 3,3′,4 A combination of 4'-biphenyltetracarboxylic dianhydride and p-phenylenediamine is more preferred.

<<Copolyimide>>
Next, a new copolymerized polyimide having high heat resistance, capable of adhering at a relatively low temperature, and having high adhesive strength will be described.

As described in the background section, 4,4′-(4,4′-isopropylidenediphenoxy)bis(phthalic anhydride) (BPADA) and 1,3-bis(3-aminophenoxy)benzene. Polyimides obtained from (APB) are known. However, the polyimide composed of BPADA and APB has a high storage elastic modulus even at 300° C. or higher, and it is necessary to improve the flowability of the resin for wide use. For example, when heating and pressurizing, under relatively low temperature conditions, there is a problem that the circuit pattern cannot be satisfactorily embedded during lamination and bubbles are generated along the circuit pattern.

On the other hand, there has been proposed a method of manufacturing an FPC in which a base material such as a polyimide film and a copper foil are bonded to each other by using an adhesive film obtained from a resin composition obtained by mixing polyimide with an epoxy resin or polymaleimide. However, adhesives composed of these polyimides and thermosetting resins have improved melt fluidity and can be used as adhesives, but it is necessary to take full advantage of polyimide features such as heat resistance and low dielectric loss tangent. However, it requires high temperature and a long time for adhesion, and there is a problem in workability. As a method for solving this, Patent Document 3 proposes a method in which 1 to 20% of a volatile solvent remains to ensure processability. However, usually, when used as an adhesive, the volatile solvent present in the adhesive causes swelling and the like, so that it is required to be reduced as much as possible. On the other hand, Patent Document 4 describes a method of improving Workability, in this method it is necessary to tightly regulate molecular weight, dehydrating agent performs imidization reaction in the presence of a catalyst, Furthermore, in order to remove these, it is necessary to wash with a solvent, which is inferior in economic efficiency.

For these reasons, special additive components such as solvents and complicated manufacturing methods such as washing are not required, and the polyimide itself has high heat resistance and can be bonded even at a relatively low temperature, and has high adhesion. New polyimides with strength and the like are needed. Further, it is also required to have an effect of low dielectric properties.

The copolymerized polyimide of one embodiment of the present invention is a new copolymerized polyimide that has high heat resistance, can be bonded even at a relatively low temperature, and has high adhesive strength. In another aspect of the present invention, a method for easily producing the polyimide, a heat resistant adhesive using the same, and the like are provided. It is also preferable that the copolymerized polyimide also has an effect of low dielectric properties.

As described above, the copolymerized polyimide of the present invention has a mole of the general formula (1) among the copolymerized polyimides having the repeating unit represented by the general formula (1) and the repeating structure represented by the general formula (3). It is characterized in that the value calculated by (number of moles of general formula (1) + number of moles of general formula (3)) is 0.50 or more and less than 1.00.

[In the formula, X ₁ is a tetracarboxylic acid residue selected from the groups represented by the general formula (2), and X ₂ is a tetracarboxylic acid residue other than the general formula (2). ]

[R _{1 to} R ₂₀ in the formula each independently represent hydrogen, an alkyl group or halogen. ]

Here, the tetracarboxylic acid residue having two ether bonds represented by the general formula (2) is not particularly limited, but a tetracarboxylic acid containing a bisphenol skeleton represented by the following formula (5) is used. A residue, a tetracarboxylic acid residue containing a biphenol skeleton represented by formula (6), a hydroquinone represented by formula (7), and a tetracarboxylic acid residue containing a resorcinol skeleton are preferable. Further, since it has excellent heat resistance, a tetracarboxylic acid residue containing a bisphenol skeleton represented by the formula (5) is more preferable, and since the dielectric loss is small, the tetracarboxylic acid residue represented by the following formula (a) is Particularly preferred.

X _{2 in} the general formula (3) of the copolymerized polyimide of the present invention is not particularly limited as long as it is a residue of a tetracarboxylic acid other than the general formula (2), but it is represented by the general formula (4). It is preferable to use any one of the carboxylic acid residues or a mixture thereof, and the tetracarboxylic acid residue having no ether bond has a relatively rigid structure. It is more preferable because the entanglement is reduced and the fluidity at the glass transition temperature or higher is excellent. Furthermore, since these tetracarboxylic acid anhydrides are superior in reactivity as compared with tetracarboxylic acid anhydrides having an ether bond, a copolymerized polyimide can be easily obtained. Further, it is preferably a tetracarboxylic acid residue having no ketone bond, and the ketone bond causes a cross-linking reaction at the time of heating, which lowers the fluidity of the polyimide. In particular, the residue of biphenyltetracarboxylic acid and the residue of pyromellitic acid are more preferable because the above-mentioned object can be achieved in a small amount, and the residue of biphenyltetracarboxylic acid is preferable because they can be achieved in a smaller amount.

In the present invention, in the copolymerized polyimide having the repeating unit represented by the general formula (1) and the repeating structure represented by the general formula (3), the number of moles of the general formula (1)/[the general formula (1) The number of moles of + + the number of moles of the general formula (3)] is not particularly limited as long as it is 0.50 or more and less than 1.00. However, since the glass transition temperature is low, 0.72 to 0. Since 99 is preferable and the adhesiveness is excellent, 0.72 to 0.98 is more preferable, and 0.95 to 0.98 is particularly preferable because the adhesiveness is excellent especially at a low temperature.

The weight average molecular weight of the copolymerized polyimide of the present invention, which is determined by GPC, is preferably 5,000 to 1,000,000, and is 10,000 to 500,000 because of excellent adhesiveness. Is more preferable, and since it is excellent in heat resistance, it is particularly preferable that it is 50,000 to 500,000.

The copolymerized polyimide of the present invention is not particularly limited, but the glass transition temperature obtained from the peak of tan δ in dynamic viscoelasticity measurement measured with a film having a thickness of 5 to 150 μm is less than 240° C., preferably Is less than 205°C, more preferably less than 200°C, even more preferably 150 to 190°C, and particularly preferably 150 to 180°C. The glass transition temperature here is, for example, using a film having only a thermoplastic polyimide layer or a multilayer polyimide film, and dynamic viscoelasticity measurement (DMS), thermomechanical analysis (TMA), differential scanning calorimetry (DSC), Any glass transition temperature obtained by a differential thermal analysis (DTA) and using known conditions and analysis methods may be used. Within this range, it is possible to bond at a relatively low press temperature of 240° C. or less, which is preferable.

The copolymerized polyimide of the present invention is not particularly limited, but the temperature at which the storage elastic modulus in dynamic viscoelasticity measurement measured with a film having a film thickness of 5 to 150 μm is 5×10 ⁶ Pa or less is preferable. It is 210° C. or lower, more preferably 100 to 200° C., further preferably 150 to 195° C., and particularly preferably 170 to 190° C. The temperature at which the storage elastic modulus is 10 ⁶ Pa or lower is preferably 280° C. or lower, more preferably 100 to 250° C., further preferably 150 to 230° C., and particularly preferably 170 to 220° C. The temperature at which the storage elastic modulus is 5×10 ⁵ Pa or lower is preferably 300° C. or lower, more preferably 100 to 280° C., further preferably 150 to 260° C., and particularly preferably 170 to 240° C. Furthermore, the temperature at which the storage elastic modulus is 10 ⁵ Pa or lower is preferably 350° C. or lower, more preferably 100 to 300° C., further preferably 150 to 280° C., and particularly preferably 170 to 260° C. Within this range, it is possible to bond at a relatively low pressing temperature of 240° C. or less, which is preferable.

The copolymerized polyimide of the present invention is not particularly limited, but the storage elastic modulus at 200° C. is preferably 6×10 ⁶ Pa or less in dynamic viscoelasticity measurement measured with a film having a thickness of 5 to 150 μm. It is more preferably 1×10 ^{5 to} 5×10 ⁶ Pa, and particularly preferably 5×10 ⁵ to 4×10 ⁶ Pa. The storage elastic modulus at 210° C. is preferably 5×10 ⁶ Pa or less, more preferably 0.1×10 ^{5 to} 4.5×10 ⁶ Pa, and particularly preferably 1×10 ^{5 to} 3×10 ⁶ Pa. is there. The storage elastic modulus at 220° C. is preferably 4×10 ⁶ Pa or less, more preferably 0.1×10 ⁵ to 2×10 ⁶ Pa, and particularly preferably 1×10 ⁵ to 1×10 ⁶ Pa. Within this range, it is possible to bond at a relatively low pressing temperature of 240° C. or less, which is preferable.

Although not particularly limited, the viscoelasticity of the copolymerized polyimide of the present invention is, as shown in FIG. 3, compared with the viscoelasticity of conventional polyimide (FIG. 4), stored in a high temperature range from around 200° C. A remarkable decrease in elastic modulus was confirmed. Therefore, it has been clarified that the copolymerized polyimide of the present invention has properties which are significantly different from those of the conventional polyimide in a high temperature range from around 200°C.

The copolymerized polyimide of the present invention is not limited, but since it has heat resistance that enables simultaneous production of a conventional polyimide film, it has a 1% weight loss temperature determined by thermogravimetric analysis (TGA). The temperature is preferably 400°C or higher, more preferably 450°C or higher, and particularly preferably 460°C or higher. Although not particularly limited, the TGA was measured in a nitrogen stream at a temperature rising rate of 10° C./min from 25° C. to 600° C., and the 1% weight loss temperature obtained from the obtained weight curve was measured. It can be suitably adopted.

The copolymerized polyimide of the present invention is not limited, but has a relative dielectric constant at 1 kHz to 10 GHz of preferably 3.4 or less, more preferably 3.2 or less, and particularly preferably 3.1 or less. The tangent is preferably 0.010 or less, more preferably 0.005 or less, and particularly preferably 0.003 or less. Within this range, it can be suitably used as an insulating material or an adhesive for high frequency circuits. Although not particularly limited, the relative permittivity and the dielectric loss tangent measured in the normal state (C-96/20/65) based on JIS C6481 can be preferably used. Known measuring devices and methods can be preferably used.

The copolymerized polyimide of the present invention is not particularly limited, but is a polyimide obtained by reacting a tetracarboxylic acid component and a diamine component, and the total number of moles of the tetracarboxylic acid component is the total moles of the diamine component. The number is preferably 0.5 to 10 mol% excess, more preferably 1 to 7 mol% excess, and particularly preferably 1 to 5 mol% excess. Within this range, the adhesiveness at low temperature and the heat resistance can both be achieved, which is preferable. This is for the purpose of adjusting the polyimide molecular weight, and in addition to using the residue of the tetracarboxylic acid represented by the general formula (4), the entanglement between the polymer chains is reduced, which is effective in improving the adhesiveness. There is. The obtained polyimide contains a tetracarboxylic acid residue based on the tetracarboxylic acid component used as a raw material and a diamine residue based on the diamine component at a ratio corresponding to the charged molar ratio.

The copolymerized polyimide of the present invention is not limited, but since it has a low dielectric loss, it is preferable that the water absorption obtained by immersion in water according to ASTM D570 23° C. for 24 hours is 1.4% or less. It is preferably 1.0%, particularly preferably 0.8% or less.

[Application of Copolymerized Polyimide]
The copolymerized polyimide of the present invention can be used for various purposes. One of the preferable applications is the above-mentioned multilayer polyimide film (that is, a layer (A) containing a thermoplastic polyimide (A) having a glass transition temperature of less than 240°C, and a heat-resistant polyimide having a glass transition temperature of 240°C or more ( A multilayer polyimide film containing a layer (B) containing B)), which can be suitably used as the thermoplastic polyimide (A) of this multilayer polyimide film.

The heat-resistant adhesive of the present invention (the same applies to the heat-resistant adhesive film, adhesive-attached metal foil, adhesive-attached resin film, laminate, and circuit described below) is characterized by containing the above-mentioned copolymerized polyimide. Although not particularly limited, the copolymer polyimide of the present invention is preferably 30% by mass or more, and more preferably 50% by mass in the heat resistant adhesive because it has excellent heat resistance. Further, since the electric conductivity loss is small, 80% by mass is preferable, 90% by mass or more is more preferable, and 95% by mass or more is particularly preferable. Further, this heat-resistant adhesive (heat-resistant adhesive film, adhesive-attached metal foil, adhesive-attached resin film, and laminated body, which will be described later) includes epoxy resin, phenol resin, acrylic resin, cyanate resin, BT resin, etc. The thermosetting resin, the inorganic filler, the pigment, the dye, the antioxidant, the plasticizer, the solvent and the like can be suitably added. However, in the present invention, the copolymerized polyimide is a thermoplastic resin that can be bonded at a low temperature for a short time (heat fusion property, thermocompression bonding property) without containing a substance that plasticizes the layer such as a plasticizer or a solvent. Therefore, it is not necessary to include additives such as a plasticizer and a solvent. From the viewpoint of durability and mechanical properties, it is also preferable to use an all-polyimide composition containing no thermosetting resin or thermoplastic resin.

The heat-resistant adhesive of the present invention (the heat-resistant adhesive film, the adhesive-attached metal foil, the adhesive-attached resin film, the laminate, and the circuit described later) of the present invention can retain the adhesiveness even when exposed to high temperatures. .. Although not particularly limited, the half-time of 90° peel strength in a 150°C heat resistance test (the maximum time of 0.5 or more when the peel strength before the test is 1) is preferably 100 hours. As described above, more preferably 1000 hours or longer, and further preferably 3000 hours or longer.

The heat-resistant adhesive film of the present invention is characterized by being an adhesive film containing the copolymerized polyimide of the present invention and having a film thickness of 1 to 250 μm. Since the film thickness is excellent in productivity, the film thickness is more preferably 5 to 150 μm, and since the embedding property is excellent, the film thickness is particularly preferably 10 to 150 μm.

The adhesive-attached metal foil of the present invention is characterized in that the adhesive layer contains the copolymerized polyimide of the present invention. Although not particularly limited, the metal foil used here (same for the laminated body described below) may be any of various metal foils such as copper, aluminum, gold, nickel foil and alloy foil such as stainless steel. it can. Of these, copper foil is preferably used. Specific examples of the copper foil include rolled copper foil and electrolytic copper foil. As the metal foil, any surface roughness can be used, but one having a surface roughness Rz of 0.5 μm or more is preferable. The surface roughness Rz of the metal foil is preferably 7 μm or less, and particularly preferably 5 μm or less. Such metal foils, eg copper foils, are known as VLPs, LPs (or HTEs). The thickness of the metal foil is not particularly limited, but is preferably 2 to 35 μm, particularly 5 to 18 μm. For the metal foil having a thickness of 5 μm or less, a metal foil with a carrier, for example, a copper foil with an aluminum foil carrier can be used.

On the other hand, the film thickness of the adhesive used for the adhesive-attached metal foil is more preferably 1 to 150 μm because it is excellent in productivity, and particularly preferably 3 to 150 μm because it is excellent in embedding property.

The resin film with an adhesive of the present invention is characterized in that the adhesive layer contains the copolymerized polyimide of the present invention. Although not particularly limited, a polyimide film, a PET film, a PEN film, a COP film, a polycarbonate film, or the like can be preferably used as the resin film used here, and a polyimide film is preferable because it is particularly excellent in heat resistance. On the other hand, the adhesive used for the resin film with an adhesive is formed on one side or both sides of the film, and the film thickness is more preferably 1 to 150 μm because it is excellent in productivity, and the film thickness is excellent because it is excellent in embedding property. 3 to 150 μm is particularly preferable.

The polyimide laminate using the copolymer of the present invention is a laminate in which a glass layer, an inorganic layer such as a ceramic layer, an organic layer such as a resin layer, or a metal layer and an adhesive layer containing the copolymerized polyimide of the present invention are laminated. It is the body. The film thickness of the laminate adhesive is more preferably 1 to 150 μm because it is excellent in productivity, and particularly preferably 3 to 150 μm because it is excellent in embedding property.

The electronic circuit of the present invention is characterized by using an insulating layer containing the copolymerized polyimide. Although it is not particularly limited, it is suitable for rigid printed circuits using glass/epoxy substrates, flexible printed circuits using resin film substrates such as polyimide, and ceramic circuits using inorganic substrates due to its excellent electrical insulation and dielectric properties. It can be preferably used. In particular, since it has excellent insulation reliability, it can be used for an insulating layer of a fine pitch circuit. The line width and the space width are preferably 100 μm or less, more preferably 50 μm or less, still more preferably 20 μm or less, and particularly preferably 1 to 10 μm. This range is preferable because long-term insulation reliability can be obtained.

The electronic circuit of the present invention has excellent fluidity when the insulating layer containing the above-mentioned copolymerized polyimide is heated, and therefore the temperature is preferably 200°C or lower, more preferably 190°C or lower, and particularly preferably 180°C or lower at a pressing temperature. Can be glued. Furthermore, it is possible to embed a fine-pitch wiring pattern at the above temperature, and preferably the line width and the space width are also 100 μm or less, more preferably 50 μm or less, further preferably 20 μm or less, and particularly preferably 1 to 10 μm. Is.

The copolymerized polyimide of the present invention can be easily obtained by a conventional polyimide manufacturing method, can be bonded even at a relatively low temperature, and can achieve high heat resistance, high adhesive strength and low dielectric properties, and thus can be used as a heat resistant adhesive for electronic materials. It can be suitably used as an agent. Specifically, coverlays, interphase adhesives for multi-layer boards, bonding sheets for multi-layer boards, embedded resins for component-embedded boards, encapsulation resins, underfills, adhesive layers for copper-clad laminates, adhesive layers for TAB tape, etc. is there.

(Production of copolymerized polyimide)
The method for producing the copolymerized polyimide of the present invention can be produced by various methods known to those skilled in the art, and generally, it is obtained by dehydrating and ring-closing polyamic acid which is a corresponding polyimide precursor. Polyamic acid is obtained by reacting a tetracarboxylic acid component and a diamine component.

As the diamine component, 1,3-bis(3-aminophenoxy)benzene (APB) is used. Other diamine compounds may be contained within a range not impairing the object of the present invention, but are preferably 20 mol% or less, more preferably 10 mol% or less, and 0% (APB only) is also preferable.

The tetracarboxylic acid component giving the repeating unit represented by the general formula (1) is a tetracarboxylic acid component (tetracarboxylic dianhydride, tetracarboxylic acid) from which X ₁ is introduced, that is, the residue represented by the general formula (2). Acid). The tetracarboxylic acid component that gives the repeating unit represented by the general formula (3) is a tetracarboxylic acid component (tetracarboxylic dianhydride, tetracarboxylic acid) from which a residue other than the formula (2) is derived. In producing the copolymerized polyimide of the present invention, the tetracarboxylic acid component giving the general formula (1) and the tetracarboxylic acid component giving the general formula (3) are used in combination. The molar ratio of the combination, the preferable tetracarboxylic acid component, and the like correspond to the above description of the tetracarboxylic acid residue and the polyimide structure.

As a typical procedure of the reaction, there is a method of dissolving or dispersing a diamine component in an organic polar solvent, and then adding a tetracarboxylic dianhydride component to obtain a polyamic acid solution. The addition order of each monomer is not particularly limited, but it is preferable to add the diamine to the organic polar solvent first and add the tetracarboxylic acid dianhydride while adjusting the viscosity of the solution. At this time, when the diamine is in an excessive amount, it is preferable to add tetracarboxylic acid to make it equimolar.

Further, as described above, it is also preferable that the number of moles of the tetracarboxylic acid component is in excess of the number of moles of the diamine component, in this case, the amount of the tetracarboxylic acid dianhydride and the diamine component are equimolar amounts, and The excess tetracarboxylic acid component may be tetracarboxylic acid. It is preferred to react equimolar tetracarboxylic dianhydride and diamine and then add the tetracarboxylic acid at the end.

The term "dissolved" as used herein refers to a case where the solvent is in a state similar to that in which the solute is substantially dispersed in the solvent, in addition to the case where the solute is completely dissolved. Including. Examples of the organic polar solvent used in the polyamic acid polymerization reaction include sulfoxide-based solvents such as dimethyl sulfoxide and diethyl sulfoxide, formamide-based solvents such as N,N-dimethylformamide and N,N-diethylformamide, and N,N-. Acetamide-based solvents such as dimethylacetamide and N,N-diethylacetamide, pyrrolidone-based solvents such as N-methyl-2-pyrrolidone, phenol, o-, m- or p-cresol, xylenol, halogenated phenols, phenols such as catechol Examples include system solvents, hexamethylphosphoramide, γ-butyrolactone, and the like. Furthermore, if necessary, these organic polar solvents may be used in combination with an aromatic hydrocarbon such as xylene or toluene.

The polyamic acid solution obtained above is dehydrated and cyclized by a thermal or chemical method to obtain a thermoplastic polyimide. A thermal method of heat-treating the polyamic acid solution to dehydrate it, and a chemical method of dehydrating using a dehydrating agent. Any of the methods can be used. Further, a method of heating under reduced pressure for imidization can also be used. Each method will be described below.

As a method of thermally dehydrating and ring-closing, a method of performing the imidization reaction of the above polyamic acid solution by heat treatment and, at the same time, evaporating the solvent can be exemplified. By this method, a solid polyimide resin can be obtained. The heating conditions are not particularly limited, but it is preferable to perform the heating at a temperature of 200° C. or lower for 3 minutes to 120 minutes in the time range of 1 minute to 200 minutes after removing the organic solvent. ..

Further, as a method of chemically dehydrating and ring-closing, a method of carrying out a dehydration reaction by adding a stoichiometric or more stoichiometric agent and a catalyst to the above polyamic acid solution and evaporating an organic solvent can be exemplified. Thereby, a solid thermoplastic polyimide resin can be obtained. Examples of the dehydrating agent by the chemical method include aliphatic acid anhydrides such as acetic anhydride and aromatic acid anhydrides such as benzoic anhydride. Examples of the catalyst include aliphatic tertiary amines such as triethylamine, aromatic tertiary amines such as dimethylaniline, heterocyclic primary amines such as pyridine, α-picoline, β-picoline, γ-picoline and isoquinoline. Examples thereof include tertiary amines. The condition for the chemical dehydration ring closure is preferably a temperature of 100° C. or lower, and the evaporation of the organic solvent is preferably carried out at a temperature of 200° C. or lower for a period of about 5 minutes to 120 minutes.

Further, as another method for obtaining the thermoplastic polyimide resin, there is a method in which the solvent is not evaporated in the above-mentioned method of thermally or chemically performing dehydration ring closure. Specifically, a thermoplastic polyimide resin solution obtained by performing a thermal imidization treatment or a chemical imidization treatment with a dehydrating agent in a solvent is put into a poor solvent to precipitate the thermoplastic polyimide resin, It is a method of obtaining a solid thermoplastic polyimide resin by removing reaction monomers, refining and drying. As the poor solvent, a material that is well mixed with the solvent but the thermoplastic polyimide is difficult to dissolve is selected, and examples thereof include acetone, methanol, ethanol, isopropanol, benzene, methyl cellosolve, and methyl ethyl ketone. Not limited to.

Moreover, the method of heating under reduced pressure and imidizing is also mentioned. According to this imidization method, water generated by imidization can be positively removed out of the system, so that hydrolysis of the polyamic acid can be suppressed and a high molecular weight thermoplastic polyimide can be obtained. Further, according to this method, the ring-opened product on one side or both sides present as an impurity in the starting tetracarboxylic acid dianhydride re-closes the ring, so that the effect of further improving the molecular weight can be expected.

The heating condition of the method of heating and imidizing under reduced pressure is preferably 80 to 400° C., more preferably 100° C. or higher, and more preferably 120° C. or higher, which allows the imidization to be efficiently performed and water is efficiently removed. .. The maximum temperature is preferably equal to or lower than the thermal decomposition temperature of the desired thermoplastic polyimide, and a normal imidization completion temperature, that is, about 250 to 350° C. is usually applied. The condition of the pressure for reducing the pressure is preferably a low pressure condition, specifically, 0.9 to 0.001 atm, preferably 0.8 to 0.001 atm, more preferably 0.7 to 0.01 atm. ..

(Method for producing laminate containing copolymerized polyimide)
The method for producing a laminate containing the copolymerized polyimide of the present invention is a glass layer, a resin layer, a ceramic layer, or a polyamic acid solution, cast or applied to any one of the layers,
By heat treatment, a method for producing a laminate containing a copolymerized polyimide,
The copolymerized polyimide has a repeating unit represented by the general formula (1) and a repeating structure represented by the general formula (3), and the number of moles of the general formula (1)/[the general formula (1 1) + the number of moles of the general formula (3)] is 0.50 or more.

[In the formula, X ₁ is a tetracarboxylic acid residue selected from the groups represented by the general formula (2), and X ₂ is a tetracarboxylic acid residue other than the general formula (2). ]

[R _{1 to} R ₂₀ in the formula each independently represent hydrogen, an alkyl group or halogen. ]

The glass layer used here, an inorganic layer such as a ceramic layer, an organic layer such as a resin layer, a metal layer is not particularly limited, but those having excellent heat resistance are preferable, a glass layer, a resin layer such as a polyimide film, A metal layer such as copper foil or stainless foil is more preferable. On the other hand, the temperature of the heat treatment is not particularly limited, but the organic solvent is removed at a temperature of 200° C. or lower for a time period of 3 minutes to 120 minutes, and then at a temperature of 400° C. or lower for a time period of 1 minute to 200 minutes. Is preferred.

The method for producing a heat-resistant adhesive film of the present invention is obtained by peeling one of the glass layer, the resin layer, the ceramic layer and the metal layer from the method for producing a laminate containing the above-mentioned copolymerized polyimide. It is characterized by being. The peeling method is not particularly limited, but it is preferable to previously subject the carrier layer to a treatment with a peeling agent, and it is preferable to add an internal peeling agent or the like to the copolymerized polyimide.

The method for producing a multilayer polyimide laminate of the present invention is a copolymer polyimide laminate obtained by the above method, or a heat resistant adhesive film, further a glass layer, an inorganic layer such as a ceramic layer, an organic layer such as a resin layer. Alternatively, it can be obtained by stacking and laminating with a metal layer. The bonding method is not particularly limited, but hot pressing, vacuum hot pressing, roll laminating, RTM molding, vacuum bag molding and the like can be preferably used. Since the copolymerized polyimide of the present invention has excellent moldability, it can be bonded under conditions of relatively low temperature, low pressure and short time. Therefore, the bonding temperature is preferably 150 to 240° C., more preferably 180° C. to 220° C. C, particularly preferably 180 to 200° C., the pressure is preferably 0.01 to 10 MPa, more preferably 0.1 to 5 MPa, particularly preferably 0.5 to 3 MPa, and the pressure bonding time is preferably Is 30 minutes or less, more preferably 10 minutes or less, and particularly preferably 10 seconds to 1 minute.

Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples. The present invention is not limited to the examples below.

The raw materials used in each of the following examples are as follows.
[Tetracarboxylic Acid Component Used in General Formula (1)]
4,4'-(4,4'-isopropylidenediphenoxy)bis(phthalic anhydride): BPADA
4,4'-(p-phenylenedioxy)bis(phthalic anhydride): HQDA
[Tetracarboxylic Acid Component Used in General Formula (3)]
3,3′,4,4′-biphenyltetracarboxylic dianhydride: s-BPDA
3,3′,4,4′-biphenyltetracarboxylic acid: s-BPTA
2,3,3',4'-biphenyltetracarboxylic dianhydride: a-BPDA
2,3,3′,4′-biphenyltetracarboxylic acid: a-BPTA
[Other tetracarboxylic acid components]
Pyromellitic anhydride: PMDA
[Diamine component]
1,3-bis(3-aminophenoxy)benzene:APB
Paraphenylenediamine: PPD
4,4'-diaminodiphenyl ether: DADE
2,2-bis[4-(4-aminophenoxy)phenyl]propane: BAPP
[solvent]
N,N-dimethylacetamide: DMAc
[Other]
Polyimide film having heat-resistant polyimide layer (B'): The glass transition temperature on the high temperature side determined by dynamic viscoelasticity measurement of this polyimide film was 342°C.

Polyimide substrate: A copper foil of Upicel N manufactured by Ube Eximo Co., Ltd. was etched to form a polyimide surface.

Copper foil: Mitsui Kinzoku Co., Ltd. 3EC-VLP (thickness 18 μm) washed by a known method was used.

In each of the following examples, evaluation was performed by the following method.

[Rotation viscosity]
The viscosity of the polyimide precursor solution at a temperature of 30° C. and a shear rate of 2 sec ⁻¹ was determined by using a Toki Sangyo TV-22E rotational viscometer.
[Varnish solids]
1 g of the polyimide precursor solution was weighed on an aluminum petri dish, heated in a hot air circulation oven at 200° C. for 2 hours to remove anything other than the solid content, and the solid content of the varnish (heating residue mass%) was determined from the mass of the residue. It was

Evaluation of polyimide film [Dynamic viscoelasticity measurement: storage elastic modulus (E'), loss elastic modulus (E"), glass transition temperature]
A polyimide film having a film thickness of about 25 μm was cut into a strip shape to obtain a test piece, which was measured under the following conditions using a dynamic viscoelasticity measuring device RSA-G2 manufactured by TA Instruments, and a storage elastic modulus (E′) and a loss elastic modulus were measured. The glass transition temperature was determined from the peaks of (E″) and tan δ.

Measurement mode: Tension mode SWEEP TYPE: Temperature step 3°C/min Soak time 0.5min
Frequency: 1 Hz (6.28 rad/sec)
Strain: 0.2-2%
Temperature range: From 25℃ to measurement limit Atmosphere: In air flow
[Thermo-mechanical properties (TMA): glass transition temperature]
A polyimide film with a film thickness of about 25 μm was cut into a strip shape with a width of 4 mm to form a test piece, and using TMA-50 manufactured by Shimadzu Corporation, the chuck length was 15 mm, the load was 2 g, and the temperature was raised to 300° C. at a heating rate of 20° C./min. did. The glass transition temperature was determined from the inflection point of the obtained TMA curve.
[1% thermal weight loss temperature, amount of volatile solvent]
From 25℃ to 600℃ at a heating rate of 10℃/min in a nitrogen stream, using a differential thermogravimetric simultaneous measurement device (TG/DTA6300) manufactured by SII Nanotechnology as a test piece using a polyimide film with a film thickness of 25 μm. The temperature was raised. From the obtained weight curve, the 1% thermogravimetric reduction temperature (the temperature at which the weight was reduced by 1% based on 100°C) was determined. The amount of the volatile solvent was calculated from the weight loss% between 100 and 300°C.
[Weight average molecular weight]
A sample was prepared by dissolving a polyimide film in the same solvent as the mobile phase (N-methylpyrrolidone containing 0.05M lithium bromide) at a concentration of 0.5%, and performing gel permeation chromatography (GPC, column temperature 40°C, The weight average molecular weight was measured using a standard substance: polystyrene).
[Dielectric properties (relative permittivity, dielectric loss tangent)]
A stack of about 20 polyimide films having a film thickness of about 25 μm was used as a test piece and measured by a capacitance method (RF impedance/material analyzer HP4291B, HP16453A (manufactured by Agilent Technologies) of an impedance analyzer. What was pretreated at 65° C. and RH for 96 hours was used.
[Interlayer adhesion strength (peel strength)] (About multilayer polyimide film)
In order to measure the interlayer adhesion strength of the laminated surface of the multilayer polyimide film, only the polyimide film having the heat resistant polyimide layer (B) is pulled out from the obtained multilayer polyimide film, and the interlayer adhesion strength (90° peel strength) is measured. did. Other conditions were in accordance with JIS C6481.

Evaluation of polyimide laminate
[Peel strength with copper foil] (for multilayer polyimide film)
The multilayer polyimide film obtained in each example was overlaid with a copper foil (at this time, the multilayer polyimide film is oriented so that the thermoplastic polyimide layer (A) is in contact with the copper foil, and the glossy surface is in contact with the copper foil). Then, it was pressed at a pressure of 3 MPa for 1 minute while maintaining a predetermined temperature. The 90° peel strength of this laminate was measured in accordance with JIS C6481 (peeling strength under normal conditions).
[Peel strength with copper foil] (in case of copolymerized polyimide film)
The copolymerized polyimide film having a film thickness of about 25 μm obtained in each example was provided in the order of copper foil, copolymerized polyimide film, and copper foil (at this time, each of the two copper foils had a glossy surface in contact with the copolymerized polyimide film). The laminate was set in a hot press machine and pressed at a pressure of 3 MPa for 1 minute while maintaining a predetermined temperature to prepare a polyimide laminate. The 90° peel strength between the copper foil/copolymerized polyimide film layer of this laminate was measured according to JIS C6481 (peeling strength in a normal state).
[Peel strength with polyimide substrate] (for multilayer polyimide film)
The multilayer polyimide film obtained in each example is overlaid with a polyimide substrate (at this time, the multilayer polyimide film is oriented such that the thermoplastic polyimide layer (A) is in contact with the polyimide substrate.), set in a heat press machine, and predetermined. While maintaining the temperature, it was pressed at a pressure of 3 MPa for 1 minute. The 90° peel strength of this laminate was measured in accordance with JIS C6481 (peeling strength under normal conditions).
[Peel strength with polyimide substrate] (In case of copolymerized polyimide film)
The copolymerized polyimide film having a film thickness of about 25 μm obtained in each example was laminated on the polyimide substrate, the copolymerized polyimide film, and the polyimide substrate in this order, and set on a hot press. It pressed for a minute and the polyimide laminated body was created. The 90° peel strength (peel strength) between the polyimide substrate/copolymerized polyimide film layer of this laminate was measured according to JIS C6481.

[Example A1]
100 molar equivalents of APB (0.15 mol, 43.85 g) were placed in a reaction vessel, and DMAc was dissolved in an amount (264.70 g) in which the concentration of the diamine component and the tetracarboxylic acid component was 30% by mass. This solution was heated to 50° C., 75 molar equivalents of BPADA (58.55 g) and 25 molar equivalents of s-BPDA (11.03 g) were gradually added, and the mixture was stirred for 8 hours. Then, a polyimide precursor (a1) solution (solid content: 30% by mass) was prepared by dissolving 4 molar equivalents (2.20 g) of (dihydrate of s-BPTA) to give a uniform and viscous thermoplastic polyimide layer. Obtained.

The obtained polyimide precursor (a1) solution is applied to a glass substrate, and on the substrate as it is, 120° C. for 12 minutes, and subsequently 150° C., 180° C., 210° C., 240° C., 270° C., 300° C. for 2 minutes each. Then, finally, the temperature was continuously raised to 340° C. for thermal imidization to obtain a thermoplastic polyimide layer (A)/glass laminate. Then, the obtained polyimide/glass laminate was immersed in a hot water bath and then peeled off to obtain a thermoplastic polyimide layer (A) having a film thickness of about 25 μm. The results of measuring the properties of this polyimide film are shown in Table 1.

The thermoplastic polyimide layer (A) and the polyimide film having the heat-resistant polyimide layer (B) are overlaid, set in a hot press, and pressed at a pressure of 3 MPa for 1 minute while maintaining the temperature shown in Table 1 to obtain heat resistance. A multilayer polyimide film in which a polyimide layer and a thermoplastic polyimide layer were laminated was obtained. Table 1 shows the results of the interphase adhesive strength of this multilayer polyimide.

[Examples A2 to 8 and Comparative Example A1]
A polyimide film having a thermoplastic polyimide layer was produced in the same manner as in Example A1 except that the diamine component and the tetracarboxylic acid component were changed to those shown in Table 1, and a multilayer polyimide film was obtained by the same method. Table 1 shows the properties of the polyimide film and the results of the interphase adhesive strength of this multilayer polyimide.

As can be seen from the results shown in Table 1, since the polyimides of Examples A1 to 8 can be bonded even at a relatively low temperature of 230° C. or lower, compared with the conventional multilayered polyimide film, the processing process is remarkably increased. It was confirmed that the temperature could be lowered. In addition, it was confirmed that the interphase adhesive strength of this multilayer polyimide film was high despite the bonding at low temperature.

[Synthesis Example 1] Production of polyimide precursor solution (b1) that gives a heat-resistant polyimide layer To a reaction vessel equipped with a stirrer and a nitrogen inlet tube, dimethylacetamide (DMAc) was added, and further paraphenylenediamine (PPD) and 3 were added. , 3′,4,4′-biphenyltetracarboxylic dianhydride (s-BPDA) is reacted in an equimolar amount to give a polyimide precursor having a solid content concentration of 18% by weight and a solution viscosity at 30° C. of 120 Pa·sec. A solution (b1) was obtained. The glass transition temperature (measured by dynamic viscoelasticity measurement) of the polyimide film obtained from this polyimide precursor solution was 340°C.

[Synthesis Example 2] Production of polyimide precursor solution (b2) that gives a heat-resistant polyimide layer DMAc was added to a reaction vessel equipped with a stirrer and a nitrogen introducing tube, and PPD and 4,4-diaminodiphenyl ether as diamine components were further added. (DADE) and s-BPDA as a tetracarboxylic dianhydride component and pyromellitic dianhydride (PMDA) are supplied, and the tetracarboxylic dianhydride component and the diamine component are reacted to obtain a solid content concentration. Of 18% by weight and a solution viscosity at 30° C. of 115 Pa·sec to obtain a polyimide precursor solution (b2). Here, the molar ratio of PPD and DADE was 60:40, and the molar ratio of s-BPDA and PMDA was 30:70. The glass transition temperature (measured by dynamic viscoelasticity measurement) of the polyimide film obtained from this polyimide precursor solution was 381°C.

[Synthesis Example 3] Production of Polyimide Precursor Solution (b3) Providing Heat-Resistant Polyimide Layer DMAc was added to a reaction vessel equipped with a stirrer and a nitrogen introducing tube, and PPD as a diamine component) and 4,4-diamino. Diphenyl ether (DADE) and 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), s-BPDA and pyromellitic dianhydride (PMDA) as tetracarboxylic dianhydride components. Was supplied to react the tetracarboxylic acid dianhydride component with the diamine component to obtain a polyimide precursor solution (b3) having a solid content concentration of 18% by weight and a solution viscosity at 30° C. of 118 Pa·sec. The molar ratio of PPD, DADE and BAPP was 50:30:20. The molar ratio of s-BPDA and PMDA was 20:80. The glass transition temperature (measured by dynamic viscoelasticity measurement) of the polyimide film obtained from this polyimide precursor solution was 378°C.

[Example A9]
The polyimide precursor solution (b1) which gives the heat-resistant polyimide layer obtained in Synthesis Example 1 is applied on a glass substrate with a bar coater to a film thickness of about 150 μm and heated at 120° C. for 12 minutes to give a heat-resistant polyimide layer. A polyimide precursor (b1) layer was formed. Subsequently, the polyimide precursor (a1) solution that gives the thermoplastic polyimide layer obtained in Synthesis Example 1 was applied onto the polyimide precursor (b1) layer that gave the heat-resistant polyimide layer using a bar coater to give a film thickness of about 30 μm. Coating and heating at 120° C. for 5 minutes to obtain a self-supporting film (multilayer polyimide precursor film) in which a heat resistant (b1) layer and a thermoplastic (a1) layer were laminated on a glass substrate. This film is peeled from the glass substrate, fixed on a pin tenter, and continuously heated at 150°C, 200°C, 250°C, and 340°C for 2 minutes each to thermally imidize the film and heat-resistant polyimide layer. A multilayer polyimide film in which a plastic polyimide layer was laminated was obtained. Table 2 shows the results of measuring the peel strength using this film.

[Examples A10 to 12]
The polyimide precursor (b1) solution that gives the heat-resistant polyimide layer is the polyimide precursor (b1 to 3) solution shown in Table 2, and the polyimide precursor (a1) solution that gives the thermoplastic polyimide layer is the polyimide precursor solution shown in Table 2. A multilayer polyimide film was obtained in the same manner as in Example A1 except that (a1-2) was used. Table 2 shows the results of measuring the peel strength using this film.

[Comparative Example A2]
A multilayer polyimide film was obtained in the same manner as in Example A1, except that the polyimide precursor solution (a1) solution for providing the thermoplastic polyimide layer was changed to the polyimide precursor solution (a10) shown in Table 2. Table 2 shows the results of measuring the peel strength using this film.

The multilayer polyimide film of the present invention is excellent in heat resistance of the thermoplastic polyimide layer, so that high-temperature curing required for the production of the heat resistant polyimide film is possible, and since it has a heat resistant polyimide layer, The carrier material required for the method for manufacturing the plastic polyimide layer is not necessary (manufacturing by carrierless transportation is possible), and the manufacturing is easy. (The adhesive layer can also be manufactured by the conventional polyimide film manufacturing process.) As can be seen from the results shown in Table 2, high adhesiveness can be obtained even at a relatively low temperature press of 200° C. or lower. It was revealed that it has better processability than the plastic polyimide film.

Manufacture of flexible printed circuits and coreless multilayer circuits

[Example A13] Production of flexible printed circuit and coreless multilayer circuit The polyimide precursor solution (a2) obtained in Example A2 was used as a heat-resistant polyimide film (B) (3,3',4,4'-biphenyltetracarboxylic acid). Acid, p-phenylenediamine having a thickness of 50 μm and applied on a heat-resistant polyimide film (B) for 12 minutes at 150° C., 180° C. and 210° C. for 2 minutes each. Then, finally, the temperature was continuously raised at 240° C. for 20 minutes for thermal imidization to obtain a multilayer film of thermoplastic polyimide (A′)/heat resistant polyimide film (B). The amount of volatile solvent in this multilayer film was <0.1%.

As a flexible copper-clad laminate in which copper foil is laminated on both sides of a polyimide film containing a heat-resistant polyimide layer (B′) made of biphenyltetracarboxylic acid as a tetracarboxylic acid component and p-phenylenediamine as a diamine component, Ube Eximo A circuit pattern (line/space=20/20 μm to 1000/1000 μm) of a conductor was formed on both surfaces of a polyimide film containing a heat resistant polyimide layer (B′) by using UPICELL N manufactured by Co., Ltd. by a known patterning method.

Both sides of the circuit pattern-formed substrate were laminated so that the thermoplastic polyimide layer (A′) side of the above-mentioned multilayer film was overlapped, set in a heat press machine, and pressed at a temperature of 200° C. and a pressure of 3 MPa for 2 minutes, A printed circuit (which can be used as a flexible printed circuit or a coreless multilayer circuit) using the thermoplastic polyimide layer (A′) as an insulating layer was obtained. The structure of the multi-layer substrate here is a substrate having a circuit pattern including a heat-resistant polyimide film (B)/thermoplastic polyimide layer (A′)/heat-resistant polyimide layer (B′)/thermoplastic polyimide layer (A′). / It becomes a heat-resistant polyimide film (B'). An electron micrograph of a cross section of an electronic circuit obtained by peeling the heat-resistant polyimide film (B) as the outermost layer is shown in FIG. In addition, an electronic circuit in which a comb-shaped pattern of line/space=20/20 μm was formed was prepared by the same method. The electrical insulation reliability of this electronic circuit was measured at a temperature of 85° C., a humidity of 85% Rh, and an applied voltage of 50V. The results (relationship between test time and insulation resistance) are shown in FIG.

As a comparative example, a commercially available coverlay (adhesive layer is an epoxy resin) used for a printed circuit is laminated on both sides of a substrate on which a circuit pattern (line/space=20/20 μm) is similarly formed, and the same procedure is performed. An electronic circuit was created. The evaluation results obtained under the same conditions are shown in FIG.

[Example B1]
100 molar equivalents of APB (0.15 mol, 43.85 g) were placed in a reaction vessel, and DMAc was dissolved in an amount (264.70 g) in which the concentration of the diamine component and the tetracarboxylic acid component was 30% by mass. This solution was heated to 50° C., 75 molar equivalents of BPADA (58.55 g) and 25 molar equivalents of s-BPDA (11.03 g) were gradually added, and the mixture was stirred for 8 hours. Thereafter, 4 molar equivalents (2.20 g) of (dihydrate of s-BPTA) were dissolved to obtain a uniform and viscous copolymerized polyimide precursor solution (solid content: 30% by mass).

The obtained polyimide precursor solution is applied to a glass substrate, and directly on the substrate at 120° C. for 12 minutes, then at 150° C., 180° C., 210° C., 240° C., 270° C., 300° C. for 2 minutes each, and then finally. Then, the temperature was continuously raised to 340° C. to perform thermal imidization to obtain a copolymerized polyimide/glass laminate. Then, the obtained copolymerized polyimide/glass laminate was immersed in a hot water bath and then peeled off to obtain a copolymerized polyimide (film) having a film thickness of about 25 μm. The results of measuring the properties of this copolymerized polyimide are shown in Table 3. Table 4 shows the results of the dielectric properties.

[Examples B2 to 6]
A copolymerized polyimide (film) was obtained in the same manner as in Example B1 except that the diamine component and the tetracarboxylic acid component were changed to those shown in Table 3. The results of measuring the properties of this copolymerized polyimide are shown in Table 3.

[Comparative Examples B1 to 3]
A copolymerized polyimide (film) was obtained in the same manner as in Example B1 except that the diamine component and the tetracarboxylic acid component were changed to those shown in Table 3. The results of measuring the properties of this copolymerized polyimide are shown in Table 3.

As can be seen from the results shown in Table 3, the copolymerized polyimide of the present invention has a high 1% weight loss temperature and thus is excellent in heat resistance, and can be bonded even at a relatively low press temperature of 200°C and 210°C. Therefore, it was confirmed that the workability was also excellent. It is considered that this is because the temperature at which the storage elastic modulus is equal to or lower than a predetermined value is low, that is, the storage elastic modulus at the press temperature of 200 to 230° C. is lower than the predetermined value, and thus the processing (pressing) temperature can be lowered.

On the other hand, the polyimides of Comparative Examples B2 and B3 in which the ratio of the general formula (1) was 0.5 or less could not be bonded at the pressing temperature of 200°C. In addition, the polyimide of Comparative Example B1 in which the ratio of the general formula (1) was 1.0 did not exhibit adhesiveness although the glass transition temperature was low. It is considered that this is because it is out of the predetermined range.

Further, as shown in FIG. 3, the viscoelasticity of the copolymerized polyimide of Example B1 is significantly higher than that of the polyimide of Comparative Example B1 (FIG. 4) in the storage elastic modulus in a high temperature range from around 200° C. It was confirmed that there was a significant decrease. Therefore, the copolymerized polyimide of the present invention exhibited significantly different characteristics from the polyimide of Comparative Example B1 in the high temperature range from around 200°C.

From the above, it is considered that the copolymerized polyimide of the present invention has characteristics different from those of conventional polyimides, and thus is excellent in processability.

[Example B7]
The heat-resistant polyimide film (Upilex 50S) was coated with the polyimide precursor solution obtained in Example B2, and the heat-resistant polyimide film was directly left on the heat-resistant polyimide film at 120° C. for 12 minutes, and then at 150° C., 180° C. and 210° C., respectively. Min, and finally 20 minutes at 240° C. to continuously raise the temperature and perform thermal imidization to obtain a copolymerized polyimide/heat resistant polyimide film laminate. Then, the copolymerized polyimide was peeled off from the obtained laminate to obtain a copolymerized polyimide (film) having a film thickness of about 25 μm. The volatile solvent content of this film was <0.1%. When the adhesiveness of this copolymerized polyimide was measured by the above method, the peel strength of the copper foil was 0.80 kN/m, and the peel strength with the polyimide substrate was 1.5 kN/m or more.

[Example B8]
100 molar equivalents of APB (0.15 mol, 43.85 g) were placed in a reaction vessel, and DMAc was dissolved in an amount (273.77 g) in which the concentration of the diamine component and the tetracarboxylic acid component was 30% by mass. This solution was heated to 50° C., 80 molar equivalents of BPADA (0.12 moles, 62.45 g) were added, and while confirming the viscosity thereafter, 20 molar equivalents of the a-BPDA component (0.03 moles, 8.83 g). Furthermore, 4 molar equivalents of the a-BPTA component (0.006 mol, 2.20 g) were gradually added, and the mixture was stirred for 8 hours. Then, the mixture was cooled to obtain a uniform and viscous copolymerized polyimide precursor solution.

The obtained polyimide precursor solution is applied to a copper foil (rough surface), and then directly on the copper foil in an inert oven at 120°C for 12 minutes, followed by 150°C, 180°C, 210°C, 240°C, 270°C. , 300° C. for 2 minutes each, and then finally heated continuously to 340° C. for thermal imidization to form a copolyimide film having a thickness of about 25 μm on the surface of the adhesive-coated copper foil. Got The adhesiveness of the copper foil with the adhesive was measured by the same method as described above except that the adhesive layer surface of the copper foil with the adhesive was overlaid with the glossy surface of the copper foil or the polyimide substrate. The peel strength of the copper foil (adhesive layer and copper foil glossy surface) was 0.93 kN/m, and the peel strength of the polyimide substrate (adhesive layer and polyimide substrate) was 1.5 kN/m or more.

[Example B9]
The polyimide precursor solution composition obtained in Example B1 was applied to a copper foil (rough surface), and then directly on the copper foil in an inert oven at 120° C. for 12 minutes, followed by 150° C., 180° C., 210° C. , 240° C., 270° C., 300° C. for 2 minutes each, and finally, the temperature is continuously raised to 340° C. for thermal imidization to form a copolymerized polyimide having a thickness of about 25 μm on the surface. A copper foil with an adhesive was obtained. When the adhesiveness of the copper foil with an adhesive was measured by the method described in Example B8, the peel strength of the copper foil was 0.53 kN/m and the peel strength with the polyimide was 1.5 kN/m or more.

Adhesive film in which copolymerized polyimide is placed on the surface layer of heat-resistant polyimide [Synthesis Example 1]
Dimethylacetamide (DMAc) was added to a reaction vessel equipped with a stirrer and a nitrogen introducing tube, and further paraphenylenediamine (PPD) and 3,3′,4,4′-biphenyltetracarboxylic dianhydride (s-BPDA). ) With the above equimolar reaction to obtain a polyimide precursor solution (b1) having a solid content concentration of 18% by weight and a solution viscosity at 30° C. of 120 Pa·sec.

[Synthesis example 2]
DMAc was added to a reaction vessel equipped with a stirrer and a nitrogen introducing tube, and PPD and 4,4-diaminodiphenyl ether (DADE) as diamine components, and s-BPDA and pyromerit as tetracarboxylic dianhydride components were added. An acid dianhydride (PMDA) is supplied to react a tetracarboxylic acid dianhydride component and a diamine component, a polyimide precursor solution having a solid content concentration of 18% by weight and a solution viscosity at 30° C. of 115 Pa·sec ( b2) was obtained. The molar ratio of PPD and DADE was 60:40. The molar ratio of s-BPDA and PMDA was 30:70.

[Example B10]
The polyimide precursor solution obtained in Synthesis Example 1 was applied to a glass substrate with a film thickness of about 150 μm, and heated on the substrate as it was for 12 minutes at 120° C., followed by the copolymerization polyimide precursor solution obtained in Example B2. Was coated on the polyimide precursor film obtained in Synthesis Example 1 to a film thickness of about 30 μm, and heated at 120° C. for 5 minutes. This film is peeled off from the glass substrate, placed on a pin tenter, and continuously heated at 150°C, 200°C, 250°C, and 340°C for 2 minutes each to thermally imidize the surface, and to dispose the copolymerized polyimide on the surface. The obtained film was obtained. The volatile solvent content of this film was <0.1%. The peel strength was measured using this film. The results are shown in Table 5.

Example B11
A film having a copolymerized polyimide layer on its surface was obtained in the same manner as in Example B10, except that the copolymerized polyimide precursor solution was changed to the copolymerized polyimide precursor solution obtained in Example B2. The peel strength was measured using this film. The results are shown in Table 5.

As can be seen from the results shown in Table 5, the copolymerized polyimide of the present invention can be bonded even at 200° C. or lower, and therefore has significantly better processability than conventional polyimides. Further, since it is possible to manufacture the heat-resistant polyimide film having a glass transition temperature of more than 300° C. and the adhesive layer at the same time without requiring a special process such as chemical imidization or washing, it is also excellent in economical efficiency.

Example B12
Using the copolymerized polyimide (film) obtained in Example B7 as a heat-resistant adhesive (heat-resistant adhesive film), a copper foil with an adhesive was produced by the method described in the evaluation of the polyimide laminate. After the obtained sample was exposed to 150° C. for a predetermined time, the 90° peel strength between the copper foil/copolymerized polyimide film layer was measured according to JIS C6481 (peeling strength in a normal state). The result is shown in FIG.

In addition, as a comparative example, a commercially available adhesive sheet for electronic circuit boards (epoxy adhesive sheet) used for printed circuits was used instead of the copolymerized polyimide (film) obtained in Example B7, and the copper foil with adhesive was used. Was manufactured. The result evaluated by the same method is shown in FIG.

According to the present invention, easily obtained by a conventional polyimide film manufacturing method, capable of bonding at a low temperature in a short time, a new multilayer polyimide film realizing high heat resistance and high adhesive strength, a method for manufacturing a multilayer polyimide film, and A polyimide metal laminate using the same can be provided. Further, the multilayer polyimide film and the polyimide metal laminate of the present invention can be used as a material for electronic parts such as printed wiring boards, flexible printed boards, COFs, TAB tapes, and electronic devices. Further, the thermoplastic polyimide film of the present invention is a sealing material for tab leads of lithium ion batteries, polymer batteries, electric double layer capacitors, etc. using an aluminum laminated film as an outer bag, cover lay for flexible printed circuit boards, ceramic packages and caps. It can be suitably used as an adhesive sheet, such as a bonding material with, which requires reliability at high temperatures.

Further, the copolymerized polyimide of the present invention is a multilayer polyimide film, a glass layer, an inorganic layer such as a ceramic layer, an organic layer such as a resin layer, or a laminate with a metal layer, as a material for electronic components and electronic devices. Can be preferably used as. For example, it can be used as a heat resistant adhesive containing a copolymerized polyimide, a heat resistant adhesive film, a copper foil with an adhesive, and a resin film with an adhesive.

Claims (34)

A multilayer polyimide film including a layer (A) containing a thermoplastic polyimide (A) having a glass transition temperature of less than 240° C. and a layer (B) containing a heat resistant polyimide (B) having a glass transition temperature of 240° C. or more. And
The layer (A) and the layer (B) are laminated on the entire surface without a circuit interposed therebetween,
The thermoplastic polyimide (A) has a repeating unit represented by the general formula (1) and a repeating structure represented by the general formula (3) in the number of moles of the general formula (1)/[the mole of the general formula (1)]. [Number + number of moles of general formula (3)] having a value in the range of 0.48 to 1 (however, when the value is 1, the repeating structure represented by general formula (3) (Not included) is a multilayer polyimide film.
[In the formula, X ₁ is a tetracarboxylic acid residue selected from the group represented by the general formula (2), and X ₂ is a tetracarboxylic acid residue other than the group represented by the general formula (2). .. ]
[R _{1 to} R ₂₀ in the formula each independently represent hydrogen, an alkyl group or halogen. ] The glass transition temperature of the said thermoplastic polyimide (A) is less than 200 degreeC, The multilayer polyimide film of Claim 1 characterized by the above-mentioned. The thermoplastic polyimide (A) is a copolymerized polyimide having a repeating unit represented by the general formula (1) and a repeating structure represented by the general formula (3). 2. The multilayer polyimide film according to 2.
[X ₂ in the formula is a residue of a tetracarboxylic acid excluding the general formula (2). ] The multilayer polyimide film according to claim 3, wherein X ₂ in the general formula (3) is a residue of a tetracarboxylic acid selected from the group represented by the general formula (4).
formula:
Number of moles of general formula (1)/(number of moles of general formula (1) + number of moles of general formula (3))
The multilayer polyimide film according to claim 3 or 4, wherein the value calculated by is 0.50 or more and less than 1.00. The heat-resistant polyimide (B) has a tetracarboxylic acid residue and a diamine residue that compose the polyimide,
3,3',4,4'-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, and 1,4-hydroquinone dibenzoate-3,3',4,4'-tetracarboxylic dianhydride A tetracarboxylic acid residue based on a tetracarboxylic acid component containing at least one selected from the group consisting of:
p-phenylenediamine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, m-tolidine and 4,4'-diaminobenz It is a polyimide which consists of a diamine residue based on the diamine component containing at least 1 sort(s) of component selected from anilide, The multilayer polyimide film of any one of Claims 1-5 characterized by the above-mentioned. The layer structure of the multilayer polyimide film has a structure in which a thermoplastic polyimide layer (A), a heat resistant polyimide layer (B), and a thermoplastic polyimide layer (A) are laminated in this order. The multilayer polyimide film according to any one of 1. A method for producing a multilayer polyimide film comprising a thermoplastic polyimide layer (A) and a heat resistant polyimide layer (B),
At least, the repeating unit represented by the general formula (1) and the repeating structure represented by the general formula (3) are represented by the number of moles of the general formula (1)/[the number of moles of the general formula (1) + the general formula (3). The number of moles] of the thermoplastic polyimide (A) has a value in the range of 0.48 to 1 (however, when the value is 1, the repeating structure represented by the general formula (3) is included. a layer of thermoplastic polyimide precursor corresponding to the precursor of no) (a), by imidizing a multilayer polyimide precursor film having a layer of heat-resistant polyimide precursor corresponding to the precursor of the heat-resistant polyimide (B) (b) production A method for producing a multi-layer polyimide film, comprising:
[In the formula, X ₁ is a tetracarboxylic acid residue selected from the group represented by the general formula (2), and X ₂ is a tetracarboxylic acid residue other than the group represented by the general formula (2). .. ]
[R _{1 to} R ₂₀ in the formula each independently represent hydrogen, an alkyl group or halogen. ] The layer of the heat-resistant polyimide precursor (b) is coated with the solution of the thermoplastic polyimide precursor (a), or the layer of the thermoplastic polyimide precursor (a) is coated with the heat-resistant polyimide precursor ( The method for producing a multilayer polyimide film according to claim 8, wherein the solution of b) is applied to obtain a multilayer polyimide precursor film. The method for producing a multilayer polyimide film according to claim 8, wherein the solution of the thermoplastic polyimide precursor (a) and the solution of the heat resistant polyimide precursor (b) are extruded in multiple layers. In a polyimide film having a layer (B) containing a heat-resistant polyimide (B) having a glass transition temperature of 240° C. or higher, a repeating unit represented by the general formula (1) and a repeating structure represented by the general formula (3). And a polyimide having a value of 0.48 to 1 calculated by the formula: the number of moles of the general formula (1)/[the number of moles of the general formula (1) + the number of moles of the general formula (3)] (however, A thermoplastic polyimide precursor (a) which is a precursor of a thermoplastic polyimide (A) having a glass transition temperature of less than 240° C. containing a repeating structure represented by the general formula (3) when the value is 1 ) A method for producing a multi-layer polyimide film, which comprises applying the above solution and imidizing.
[In the formula, X ₁ is a tetracarboxylic acid residue selected from the group represented by the general formula (2), and X ₂ is a tetracarboxylic acid residue other than the group represented by the general formula (2). .. ]
[R _{1 to} R ₂₀ in the formula each independently represent hydrogen, an alkyl group or halogen. ] The number of moles of the general formula (1)/[the number of moles of the general formula (1) + the number of moles of the general formula (3)] between the repeating unit represented by the general formula (1) and the repeating structure represented by the general formula (3) The number of moles] is a thermoplastic polyimide (A) having a glass transition temperature of less than 240° C. in the range of 0.48 to 1 (however, when the value is 1, it is represented by the general formula (3). A polyimide film having a layer (A) containing a repeating structure ) and a polyimide film having a layer (B) containing a heat-resistant polyimide (B) having a glass transition temperature of 240° C. or higher on the entire surface. A method for producing a multi-layer polyimide film, which comprises laminating a circuit without sandwiching the circuit therebetween.
[In the formula, X ₁ is a tetracarboxylic acid residue selected from the group represented by the general formula (2), and X ₂ is a tetracarboxylic acid residue other than the group represented by the general formula (2). .. ]
[R _{1 to} R ₂₀ in the formula each independently represent hydrogen, an alkyl group or halogen. ] One side or both sides of the multilayer polyimide film according to any one of claims 1 to 7 or the multilayer polyimide film manufactured by the manufacturing method according to any one of claims 8 to 12, of a metal layer, an inorganic layer, and an organic layer. A polyimide laminate, wherein any one of them is laminated. 1) a step of forming a circuit pattern of a conductor on one side or both sides of a polyimide film (B′) containing a layer (B′) containing a heat resistant polyimide (B′) having a glass transition temperature of 240° C. or higher, and 2) A polyimide film (A′) including at least one layer (A′) containing a polyimide film (B′) having this circuit pattern formed thereon and a thermoplastic polyimide (A′) having a glass transition temperature of less than 240° C. ), and heating and pressure bonding at a temperature of 240° C. or lower, wherein the polyimide film (A′) is the multilayer polyimide film according to any one of claims 1 to 7. Flexible printed circuit or coreless multilayer circuit manufacturing method. A copolymerized polyimide having a repeating unit represented by the general formula (1) and a repeating structure represented by the general formula (3), wherein the number of moles of the general formula (1)/[the number of moles of the general formula (1) + The number of moles of the general formula (3)] is 0.72 to 0.99, a copolymerized polyimide.
[In the formula, X ₁ is a tetracarboxylic acid residue selected from the group represented by the general formula (2), and X ₂ is a tetracarboxylic acid residue other than the group represented by the general formula (2). .. ]
[R _{1 to} R ₂₀ in the formula each independently represent hydrogen, an alkyl group or halogen. ] The copolymerized polyimide according to claim 15, wherein X ₂ is a residue of a tetracarboxylic acid selected from the group represented by formula (4).
The weight average molecular weight determined by GPC is 5,000 to 1,000,000, and the copolymerized polyimide according to claim 15 or 16 . Any one of claims 15 to 17 in which the glass transition temperature obtained from the tanδ of dynamic viscoelasticity measurement at a film having a thickness of 5~150μm created in copolymerized polyimide and less than 240 ° C. The copolymerized polyimide described in 1. 16. The temperature at which the storage elastic modulus is 5×10 ⁶ Pa or less in the dynamic viscoelasticity measurement measured with a film having a thickness of 5 to 150 μm made of copolymerized polyimide is 210° C. or less. The copolymerized polyimide according to any one of items 1 to 18 . The storage elastic modulus at 200° C. in dynamic viscoelasticity measurement measured with a film having a thickness of 5 to 150 μm made of a copolymerized polyimide is 6×10 ⁶ Pa or less, and any one of claims 15 to 19 is characterized. The copolyimide according to item 1. The 1% weight loss temperature determined by thermogravimetric analysis (TGA) is 400° C. or higher, and the copolymerized polyimide according to any one of claims 15 to 20 . The relative dielectric constant at any frequency of 1 kHz to 10 GHz is 3.4 or less and the dielectric loss tangent is 0.010 or less, and the copolymerized polyimide according to any one of claims 15 to 22 . The number of all the tetracarboxylic acid residues contained in the copolymerization polyimide is 0.5 to 10% in excess of the number of all the diamine residues, and any one of claims 15 to 22 characterized by the above-mentioned. The copolymerized polyimide described. A polyimide film comprising the copolymerized polyimide according to any one of claims 15 to 23. Heat-resistant adhesive which comprises a copolymerized polyimide according to any one of claims 15 to 23. A heat-resistant adhesive film comprising the copolymerized polyimide according to any one of claims 15 to 23 . Metal foil with an adhesive, characterized in that it comprises an adhesive layer comprising a copolymerized polyimide according to any one of claims 15 to 23. Resin film with an adhesive, characterized in that it comprises an adhesive layer comprising a copolymerized polyimide according to any one of claims 15 to 23. Inorganic layer, either of the organic layers or the metal layer, a polyimide laminate formed by laminating an adhesive layer containing a copolymerized polyimide according to any one of claims 15 to 23. Electronic circuitry, which comprises using an insulating layer containing copolymerized polyimide according to any one of claims 15 to 23. A method for producing a copolymerized polyimide laminate, comprising a step of casting or coating a copolymerized polyimide precursor solution on any one of an inorganic layer, an organic layer or a metal layer, and heat-treating,
The copolymerized polyimide is a copolymerized polyimide having a repeating unit represented by the general formula (1) and a repeating structure represented by the general formula (3), wherein the number of moles of the general formula (1)/[the general formula The number of moles of (1) + the number of moles of the general formula (3)] is 0.72 to 0.99, the method for producing a copolymerized polyimide laminate.
[In the formula, X ₁ is a tetracarboxylic acid residue selected from the group represented by the general formula (2), and X ₂ is a tetracarboxylic acid residue other than the group represented by the general formula (2). .. ]
[In the formula, R _{1 to} R ₂₀ each independently represent hydrogen, an alkyl group, or halogen. ] A method for producing a heat-resistant adhesive film obtained by peeling one of the inorganic layer, the organic layer and the metal layer from the copolymerized polyimide laminate obtained by the method according to claim 31 . The copolymerized polyimide laminate obtained by the method according to claim 31 or the heat-resistant adhesive film obtained by the method according to claim 32 is further laminated with an inorganic layer, an organic layer or a metal layer, and the temperature is kept at 240°C or lower. A method for producing a multilayer polyimide laminate obtained by heating and laminating. 1) a step of forming a circuit pattern of a conductor on one side or both sides of a polyimide film (B′) containing a layer (B′) containing a heat resistant polyimide (B′) having a glass transition temperature of 240° C. or higher, and 2) A polyimide film (A′) including at least one layer (A′) containing a polyimide film (B′) having this circuit pattern formed thereon and a thermoplastic polyimide (A′) having a glass transition temperature of less than 240° C. ) and the lap, wherein the step of thermocompression bonding at a temperature 240 ° C. or less, the thermoplastic polyimide (a ') has a feature that it is a copolymer polyimide according to any one of claims 15 to 23 Flexible printed circuit or coreless multilayer circuit manufacturing method.