JP3395158B2 - Method for manufacturing flexible metal foil-clad laminate - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a flexible metal foil-clad laminate, and more particularly, to a flexible metal foil-clad laminate (for example, flexible copper-clad electrical laminate) which does not affect the adhesive and has excellent adhesiveness. Method for producing an insulating laminated board for use or a metal foil-clad laminated board for a printed circuit).

[0002]

2. Description of the Related Art In recent years, electronic devices have been highly functionalized and miniaturized at an extremely high speed, and electronic components used therewith have been required to be miniaturized and lightened. Further, a flexible printed wiring board (hereinafter, referred to as an FPC) having flexibility is attracting attention as a wiring board for mounting electronic parts, as compared with an ordinary hard printed wiring board, and the demand thereof is rapidly increasing.

This copper-clad laminate for FPC has a three-layer structure of a base film, an adhesive layer and a copper foil, and a polyimide film excellent in heat resistance is mainly used as the base film. As the adhesive layer, an acrylic or epoxy adhesive is generally used.
However, these adhesives have problems with respect to heat resistance, thermal deterioration, etc., and it has not been possible to fully utilize the characteristics of the polyimide film as the base. In addition, it has the drawbacks of poor workability and poor chemical resistance. In particular,
The adhesive is often a factor that determines the properties of the final product, FPC, and it has been desired to develop an adhesive that can take advantage of the excellent heat resistance and other properties of the polyimide film that is the base film.

As an adhesive for solving the above problems, various thermoplastic polyimide resins having excellent heat resistance, processability and low water absorption have been developed. Such a thermoplastic polyimide resin has a glass transition point at a relatively low temperature, and the polyimide film and the copper foil can be easily adhered by laminating at a temperature close to the glass transition point. Further, since such a thermoplastic polyimide resin can be supplied as a polyimide adhesive film, it has come to be suitably used as an adhesive for FPC. That is, a flexible copper clad laminate excellent in heat resistance and workability can be prepared by laminating a polyimide film, a thermoplastic polyimide adhesive film, and a copper foil and laminating at a temperature not lower than the glass transition point of the thermoplastic polyimide. As a result, it has become possible to easily manufacture an excellent heat resistant FPC.

[0005]

However, in the production of FPC, the polyimide film conventionally used as the base film thereof has poor adhesiveness, and in order to improve the adhesiveness, the surface of corona discharge treatment or alkali treatment is used. It is generally used after being treated.
For this reason, there have been cases where a complicated processing step is required and, conversely, the physical properties of the film have to be sacrificed for the processing.

Further, the FPC using the thermoplastic polyimide adhesive film as the adhesive layer has a problem that the reliability of the adhesiveness is poor as the wiring pattern becomes finer and finer.

Therefore, as a result of intensive research aimed at solving the above-mentioned conventional problems and providing a flexible metal foil-clad laminate excellent in adhesion without sacrificing the physical properties of the base film, the present invention was found. Was reached.

[0008]

The gist of the method for manufacturing a flexible metal foil-clad laminate according to the present invention is as follows.
In a method for producing a flexible metal foil-clad laminate comprising a polyimide film, a thermoplastic polyimide adhesive layer, and a metal foil laminated, at least one kind of the polyimide film, the thermoplastic polyimide adhesive layer, and the metal foil The silane coupling agent is attached to both sides or one side.

In the flexible metal foil-clad laminate, the silane coupling agent is an aminosilane type.

Further, in such a flexible metal foil-clad laminate, the thermoplastic polyimide adhesive layer comprises:
General formula (1) 6

[Chemical 6] (In the formula, R ₁ and R ₃ are divalent organic groups, R ₂ is a tetravalent organic group, and X is

[Chemical 7] It is a trivalent linking group selected from Further, m and n are positive integers. ) Consists of a thermoplastic polyimide resin.

Furthermore, in such a flexible metal foil-clad laminate, the R ₁ group in the general formula (1) is

[Chemical 8] To be selected from.

Further, in such a flexible metal foil-clad laminate, the R ₂ group in the general formula (1) is

[Chemical 9] To be selected from.

Further, in such a flexible metal foil-clad laminate, the R ₃ group in the general formula (1) is

[Chemical 10] To be selected from.

[0014]

The flexible metal foil-clad laminate according to the present invention is obtained by laminating a polyimide film, a thermoplastic polyimide adhesive layer, and at least one kind of metal foil having a silane coupling agent adhered on both sides or one side. The adhesiveness of the polyimide film can be improved by attaching a silane coupling agent.
Furthermore, particularly excellent adhesiveness can be imparted by using an aminosilane type silane coupling agent.

Further, since the adhesive layer is a thermoplastic polyimide resin, the flexible metal foil-clad laminate obtained by the method of the present invention has excellent heat resistance, chemical resistance, workability and the like. Since the thermoplastic polyimide resin represented by the general formula (1) is used, 100 to 35
The polyimide film and the metal foil can be adhered by laminating at about 0 ° C.

[0016]

EXAMPLES Examples of the method for producing a flexible metal foil-clad laminate according to the present invention will be described below by taking a flexible copper-clad laminate using a copper foil as a metal foil as an example.

The flexible copper-clad laminate in the present invention is produced by laminating at least one kind of a polyimide film, a thermoplastic polyimide adhesive film, and a copper foil coated with a silane coupling agent on one or both sides.

First, the polyimide film and the thermoplastic polyimide adhesive film used in the present invention have the general formula (2) H ₂ N--Ar ₁ --NH ₂ (2) (wherein Ar ₁ is a divalent aromatic group). Group) and at least one diamine component represented by the general formula (3)

[Chemical 11] (In the formula, Ar ₂ represents a tetravalent aromatic group.) It can be obtained by a known method using at least one acid dianhydride component. That is, it can be obtained by forming a polyamic acid obtained by a polymerization reaction of such a diamine component and an acid dianhydride component into a film in a solution state and subjecting this to dehydration ring closure, that is, imidization.

More specifically, the polyimide film used as the base film in the present invention is, for example,
The Ar ₁ group in the general formula (2) is

[Chemical 12] Principal component represented by ones in, Ar ₂ in formula (3)
Group 13

[Chemical 13] What is obtained by using as a main component the thing represented by is typical.

The polyimide film used in the present invention is a film obtained by molding a quasi-imide material such as polyamideimide or polyetherimide, instead of the polyimide film obtained by imidizing the polyamic acid. It can also be used, and the polyimide film in the present invention is a concept including these. Further, the polyimide film used in the present invention may be formed by adding various fillers, reinforcing agents, etc., and is not limited at all.

The thermoplastic polyimide adhesive film used as the adhesive layer in the present invention is an adhesive film containing polyimide, polyamic acid and polyisoimide, and the Ar ₁ group in the general formula (2) is

[Chemical 14] In the general formula (3), the main component is represented by
₂ groups become 15

[Chemical 15] Those obtained by using as a main component those represented by are preferably used. Further, as the acid dianhydride component, the Ar ₂ group in the general formula (3) is

[Chemical 16] A suitable thermoplastic polyimide-based adhesive film can also be obtained by using those represented by

Such a thermoplastic polyimide adhesive film has the general formula (1):

[Chemical 17] (In the formula, R ₁ and R ₃ are divalent organic groups, R ₂ is a tetravalent organic group, and X is

[Chemical 18] It is a trivalent linking group selected from Further, m and n are positive integers. ), Which is composed of a thermoplastic polyimide resin, and can be suitably used as an adhesive layer from the viewpoint of the balance of glass transition point and adhesiveness.

A flexible copper clad laminate is obtained by laminating the polyimide film and the thermoplastic polyimide adhesive film thus obtained, and at least one kind of copper foil coated with a silane coupling agent on both sides or one side. To manufacture.

Specifically, first, a silane coupling agent is applied to one side or both sides of the polyimide film to form 7
After drying at 0 to 90 ° C. for about 1 minute, the thermoplastic polyimide adhesive film is placed and laminated at 100 to 350 ° C. After that, a flexible copper-clad laminate (hereinafter,
FCCL) can be produced.

Here, as the silane coupling agent, it is particularly preferable to use an aminosilane type coupling agent, for example, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-β.
Examples thereof include (aminoethyl) γ-aminopropyltrimethoxysilane and N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane.

The silane coupling agent is used after being dissolved in a solvent. Any solvent may be used as long as it can dissolve the silane coupling agent, but alcohols such as methanol and ethanol are preferable. The concentration of the silane coupling agent dissolved in the solvent is 0.005 to 20.
If the concentration is low, the adhesion is not improved by the silane coupling agent, and if the concentration is high, a film of the silane coupling agent is formed on the surface of the polyimide film. Will be reduced. It should be noted that it is all right to add an antifoaming agent or the like for eliminating bubbles generated during application to the solution of the silane coupling agent.

As a method of applying the silane coupling agent to one or both sides of the polyimide film, the polyimide film may be dipped in a solvent solution of the silane coupling agent, or the solvent solution of the silane coupling agent may be liquefied on the polyimide film. Alternatively, there is a method of spraying in a mist state, or a method of applying with a roller impregnated with a solvent solution of a silane coupling agent, a brush, or the like, and any method may be used without any limitation.
The silane coupling agent thus coated on one side or both sides of the polyimide film is usually dried at 70 to 90 ° C. for about 1 minute until the components of the solvent evaporate.

The laminating temperature (100 to 350 ° C.)
Is a temperature in the vicinity of the glass transition point of the thermoplastic polyimide adhesive film, and is 100 to 350 depending on its composition.
A polyimide film or a copper foil can be adhered by laminating in the range of ° C. Further, it goes without saying that the copper foil may be any kind of copper foil, and particularly in the present invention, it may be a metal foil of aluminum, iron, nickel or the like other than the copper foil.

As another method for producing the flexible copper-clad laminate of the present invention, a silane coupling agent is applied to one side or both sides of a thermoplastic polyimide adhesive film by any of the above-mentioned methods to 70 to 90 ° C. Alternatively, it may be dried for about 1 minute, laminated with a polyimide film and laminated at 100 to 350 ° C., and then a copper foil may be arranged and laminated at the above temperature.

Further, as another method for producing the flexible copper-clad laminate of the present invention, a silane coupling agent is applied to one side or both sides of the copper foil by any one of the above-mentioned methods to give 70 to 9
It is dried at 0 ° C. for about 1 minute, and a polyimide film and a thermoplastic polyimide adhesive film are laminated to form 100 to 35.
You may laminate at 0 degreeC, you may arrange | position the said copper foil after that, and laminate at the said temperature.

Polyamide acid, which is a precursor of thermoplastic polyimide, is uniformly applied to one side of a polyimide film and then imidized to produce a polyimide film having adhesiveness, and one side of such film and / or copper foil or After applying silane coupling agent on both sides and drying,
You may laminate this film and this copper foil.

When the thermoplastic polyimide adhesive film has a condition that it can be used as a base film, a silane coupling agent is applied to one side or both sides of the thermoplastic polyimide adhesive film and / or the copper foil. After drying by drying, the film and the copper foil may be laminated to produce a copper clad laminate having a two-layer structure.

When a flexible copper clad laminate having a polyimide film as a base film layer and a thermoplastic polyimide resin as an adhesive layer is obtained by the above-mentioned manufacturing method, corona treatment or the like which has been conventionally performed to improve its adhesiveness, etc. It is possible to impart good adhesiveness to the polyimide film without applying the above, and it is possible to produce a flexible copper-clad laminate having excellent adhesiveness.

As to the method for producing the flexible metal foil-clad laminate according to the present invention, the embodiment of the method for producing the flexible copper-clad laminate using copper foil as the metal foil has been described above. The present invention is not limited to these examples, and the present invention can be carried out in a mode in which various improvements, changes and modifications are made based on the knowledge of those skilled in the art without departing from the spirit of the present invention. Is.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1 A polyimide film having a thickness of 25 μm (hereinafter referred to as polyimide film A) was prepared by a known method using 4,4′-diaminodiphenyl ether and pyromellitic dianhydride.
Got Also, 2,2-bis (4-hydroxyphenyl) propanedibenzoate-3,3 ′, 4,4′-benzenetetracarboxylic dianhydride and
A 25 μm thick thermoplastic polyimide adhesive film (hereinafter referred to as thermoplastic polyimide adhesive film B) was obtained by a known method using 2-bis (aminophenoxyphenyl) propane.

Next, γ-on the above polyimide film A.
Aminopropyltriethoxysilane (silane coupling agent KBE903, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.01
%, 0.1% by weight, 1% by weight, and 10% by weight of each methanol solution were applied, dried at 80 ° C. for 1 minute, and laminated with the thermoplastic polyimide adhesive film B at 280 ° C. After that, electrolytic copper foils (thickness of 35 μm, Mitsui Mining & Smelting Co., Ltd.) were laminated and laminated at 280 ° C. to prepare four types of flexible copper clad laminates (hereinafter referred to as FCCL).

The resulting FCCL was evaluated for adhesiveness by 90 ° peeling adhesive strength. Adhesive strength is measured by cutting a 3 cm x 8 cm test piece from FCCL and 3 mm
5 patterns are formed and INSTRON TENSI
LE TESTER, peeling angle 90 °, isolation speed 50
The peel strength was measured in mm / min. The average of the measured values of n = 5 was taken as the adhesive strength, and the results are shown in Table 1.

[0039]

[Table 1]

Example 2 Ethylene glycol dibenzoate-3,3 ', 4
180 using a thermoplastic polyimide adhesive film having a thickness of 25 μm (hereinafter referred to as thermoplastic polyimide adhesive film C) obtained from 4′-tetracarboxylic acid dianhydride and 2,2-bis (aminophenoxyphenyl) propane. Four types of FCCL were prepared in substantially the same manner as in Example 1 except that the FCCL was laminated.

The adhesive strength of the obtained FCCL was measured in the same manner as in Example 1, and the results are shown in Table 1.

Example 3 On the above thermoplastic polyimide adhesive film B, γ-aminopropyltriethoxysilane (silane coupling agent K
BE903, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.01% by weight, 0.1% by weight, 1% by weight, 10% by weight of each methanol solution was applied and dried at 80 ° C. for 1 minute, and then the above polyimide was used. Laminated with film A at 280 ° C. Then, electrolytic copper foils (thickness of 35 μm, Mitsui Mining & Smelting Co., Ltd.) were laminated and laminated at 280 ° C. to prepare four types of FCCL.

The resulting FCCL was evaluated for adhesive strength in the same manner as in Example 1, and the results are shown in Table 1.

Example 4 Four kinds of FCCL were prepared in substantially the same manner as in Example 3 except that the thermoplastic polyimide adhesive film C was laminated at 180 ° C., and the obtained FCCL was the same as in Example 1. And the adhesive strength was measured, and the results are shown in Table 1.
It was shown to.

Example 5 On an electrolytic copper foil (35 μm thick, Mitsui Mining & Smelting Co., Ltd.),
γ-aminopropyltriethoxysilane (silane coupling agent KBE903, manufactured by Shin-Etsu Chemical Co., Ltd.)
01% by weight. 0.1% by weight, 1% by weight and 10% by weight of each methanol solution were applied and dried at 80 ° C. for 1 minute.
After laminating the polyimide film A and the thermoplastic polyimide film B at 280 ° C., laminating the electrolytic copper foil and laminating at 280 ° C., four types of FCCL
Was produced.

The adhesive strength of the obtained FCCL was measured in the same manner as in Example 1, and the results are shown in Table 1.

Example 6 Four kinds of FCCL were prepared in substantially the same manner as in Example 5 except that the thermoplastic polyimide adhesive film C was laminated at 180 ° C., and the obtained FCCL was the same as in Example 1. And the adhesive strength was measured, and the results are shown in Table 1.
It was shown to.

Comparative Example 1 A thermoplastic polyimide adhesive film B and an electrolytic copper foil were prepared using a polyimide film A that was corona-treated and a polyimide film A that was not surface-treated at a W density of 200 Wmin / m ² , respectively. (35 μm thickness, Mitsui Mining & Smelting Co., Ltd.) were laminated and laminated at 280 ° C. to prepare two types of FCCL.

The adhesive strength of the FCCL thus obtained was measured in the same manner as in Example 1, and the results are shown in Table 2.

[0050]

[Table 2]

Comparative Example 2 The polyimide film A and the above were prepared using the thermoplastic polyimide adhesive film B which was corona-treated and the thermoplastic polyimide adhesive film B which was not surface-treated under the condition that the W density was 200 Wmin / m ^2. Two types of FCCL were produced by laminating any of the thermoplastic polyimide adhesive films B and electrolytic copper foil (thickness of 35 μm, Mitsui Mining & Smelting Co., Ltd.) and laminating at 280 ° C.

The resulting FCCL was evaluated for adhesive strength in the same manner as in Example 1, and the results are shown in Table 2.

Comparative Example 3 γ-glycidoxypropyltrimethoxysilane (silane coupling agent KBM40
3, manufactured by Shin-Etsu Chemical Co., Ltd. and γ-chloropropyltrimethoxysilane (silane coupling agent KBM57.
(3, manufactured by Shin-Etsu Chemical Co., Ltd.) 1% by weight of each methanol solution was applied, and two types of FC were prepared in the same manner as in Example 1 below.
CL was prepared.

The adhesive strength of the obtained FCCL was measured in the same manner as in Example 1, and the results are shown in Table 2.

Comparative Example 4 γ-glycidoxypropyltrimethoxysilane (silane coupling agent KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.) and γ-chloropropyltrimethoxysilane (silane cup) were formed on a thermoplastic polyimide adhesive film B. Ring agent KBM573, manufactured by Shin-Etsu Chemical Co., Ltd.) 1% by weight of each methanol solution was applied, and 2 steps were carried out in the same manner as in Example 3 below.
A variety of FCCLs were made.

The adhesive strength of the obtained FCCL was measured in the same manner as in Example 1, and the results are shown in Table 2.

Comparative Example 5 γ was formed on electrolytic copper foil (thickness of 35 μm, Mitsui Mining & Smelting Co., Ltd.)
-Glycidoxypropyltrimethoxysilane (silane coupling agent KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.)
And γ-chloropropyltrimethoxysilane (silane coupling agent KBM573, manufactured by Shin-Etsu Chemical Co., Ltd.)
Three types of FCCL were prepared in the same manner as in Example 5 below, with or without applying 1% by weight of each methanol solution.

The adhesive strength of the obtained FCCL was measured in the same manner as in Example 1, and the results are shown in Table 2.

From these results, when the aminosilane silane coupling agent was applied to any of the polyimide film, the thermoplastic polyimide adhesive film, and the copper foil, almost the same good adhesiveness was exhibited. It can be seen that the adhesiveness is not improved when a silane coupling agent other than the aminosilane type is applied. That is, by applying a silane coupling agent, particularly an aminosilane-based coupling agent as a silane coupling agent, to at least one or more surfaces or at least one type of a polyimide film, a thermoplastic polyimide adhesive layer, and a copper foil, It can be seen that good adhesiveness can be imparted. Further, it is understood that the flexible copper-clad laminate produced by the production method of the present invention exhibits adhesiveness equal to or higher than that of the flexible copper-clad laminate produced by subjecting the film surface to corona treatment as usual.

[0060]

INDUSTRIAL APPLICABILITY As described above, the flexible metal foil-clad laminate according to the present invention has a silane coupling agent, particularly aminosilane, on at least one surface of a polyimide film, a thermoplastic polyimide adhesive layer and a metal foil. It is possible to manufacture a flexible metal foil-clad laminate having excellent adhesiveness by manufacturing by laminating products coated with a system coupling agent. Also,
According to the method of the present invention, a flexible metal foil-clad laminate exhibiting adhesiveness equal to or higher than that produced by subjecting to surface treatment such as corona discharge treatment or alkali treatment in order to enhance adhesiveness. It can be manufactured. As a result, there is no need to subject the film surface to corona treatment or the like, and it is possible to manufacture a flexible metal foil-clad laminate with high reliability in adhesiveness without sacrificing the physical properties of the base film.

Further, by using a thermoplastic polyimide resin as the adhesive layer, an excellent flexible metal foil-clad laminate excellent in heat resistance, chemical resistance and workability can be obtained. Since the thermoplastic polyimide resin represented by) is used, the polyimide film and the metal foil can be laminated by laminating at about 100 to 350 ° C., and thus the flexible metal foil covering having excellent heat resistance and improved adhesiveness can be obtained. The laminated board can be easily manufactured.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI B29L 9:00 B29L 9:00 (56) Reference JP-A-2-280396 (JP, A) JP-A-2-131935 (JP , A) JP 55-18426 (JP, A) JP 2-180961 (JP, A) JP 63-189490 (JP, A) JP 62-235383 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) B32B 15/08 H05K 1/03

Claims (4)

(57) [Claims] 1. A method for producing a flexible metal foil covering, which comprises laminating a polyimide film, a thermoplastic polyimide adhesive layer, and a metal foil, wherein at least one of the polyimide film, the thermoplastic polyimide adhesive layer, and the metal foil is used. or more are adhered amino silane coupling agent on both surfaces or one surface, the thermoplastic polyimide-based contact
Chakuzaiso is, the general formula (1) of 1 [Formula 1] (In the formula, R ₁ and R ₃ are divalent organic groups, and R ₂ is tetravalent.
Is an organic group, X is of 2 ## STR2 ## It is a trivalent linking group selected from Also, m and n are positive
Is an integer. ) Thermoplastic polyimide resin
A method for producing a flexible metal foil-clad laminate, comprising: 2. The R ₁ group in the general formula (1) is represented by the following formula: The flexible metal foil-clad laminate according to claim 1, wherein the flexible metal foil-clad laminate is manufactured. 3. The R ₂ group in the general formula (1) is represented by the following formula: It is selected from the following.
A method for producing a flexible metal foil-clad laminate as described in. 4. The R ₃ group in the general formula (1) is represented by the following formula: It is selected from any one of claims 1 to 3.
A method for producing a flexible metal foil-clad laminate according to any one of 1.