WO2014171553A1

WO2014171553A1 - Metal-clad laminate body

Info

Publication number: WO2014171553A1
Application number: PCT/JP2014/061201
Authority: WO
Inventors: 辰也村上; 洋之吉本; 一也河原; 剛志稲葉
Original assignee: ダイキン工業株式会社
Priority date: 2013-04-19
Filing date: 2014-04-21
Publication date: 2014-10-23
Also published as: JP2014223798A

Abstract

The present invention addresses the problem of providing a metal-clad laminate body demonstrating excellent electrical characteristics, in which a metal layer and a substrate are strongly bonded. The present invention is a metal-clad laminate body characterized in having: a substrate layer (A) (3); layers (B) (2, 4) provided on both surfaces of the substrate layer (A), the layers (B) (2, 4) comprising a melt-processable fluorine resin; and metal layers (C) (1, 5) provided on each of the layers (B) comprising a melt-processable fluorine resin, and also characterized in that the surfaces of the layers (B) comprising the melt-processable fluorine resin that contact the substrate layer (A) are surface-processed.

Description

Metal-clad laminate

The present invention relates to a metal-clad laminate.

In recent years, electrical devices, electronic devices, and communication devices have been remarkably developed. Currently, these devices tend to use higher frequency bands. Incidentally, various flexible printed boards are usually used for these devices. Therefore, the flexible printed circuit board is also required to have excellent electrical characteristics corresponding to a high frequency band and excellent heat resistance that can withstand soldering work.

As a material for a flexible printed circuit board known so far, for example, without reducing the glass transition temperature, increasing the linear thermal expansion coefficient, increasing the hygroscopic expansion coefficient, and increasing the elastic modulus, A metal-polyimide composite having excellent adhesion, a polyimide resin from which the metal-polyimide composite is obtained, and a polyamic acid varnish composition are disclosed (for example, see Patent Document 1).

JP 2009-299008 A JP 2006-059865 A International Publication No. 2010/084867 Pamphlet

The flexible printed circuit board includes a laminated board constituted by two layers of a base material and a copper foil layer, and a laminated board constituted by three layers of a base material, an adhesive layer and a copper foil layer. Of these, in the case of a laminate composed of three layers, polyimide has been used for the base material and epoxy resin or acrylic resin has been used for the adhesive layer, but insulation, adhesion and heat resistance are not sufficient. There wasn't. Laminates composed of two layers that do not use an adhesive are also known, but the polyimide resin used for the base material has low adhesion to the metal foil, so the laminating method, casting method, metalizing method, etc. It was necessary to create using a special method, or an adhesive layer with a thermoplastic polyimide layer was required.

In Patent Document 2, an adhesive layer and an insulating layer made of a fluororesin are laminated in order of an adhesive layer, an insulating layer, and an adhesive layer on both surfaces of a film made of polyimide resin, and a copper foil layer is provided as a conductor layer on the outer surface. A disclosed high frequency substrate is disclosed.
Patent Document 3 discloses a multilayer fluororesin film in which functional group-containing thermoplastic fluororesin layers are laminated on both sides of a polyimide film, and a printed wiring board using the film.

An object of the present invention is to provide a metal-clad laminate in which a metal layer and a base material are firmly bonded in view of the above-described situation and exhibit excellent electrical characteristics.

That is, the present invention comprises a base material layer (A), a layer (B) made of a melt-processable fluororesin provided on both surfaces of the base material layer, and each of the melt-processable fluororesins. The layer (B) having a metal layer (C) provided on the layer (B) and made of the melt-processable fluororesin has a surface that is in contact with the base material layer (A). This is a metal-clad laminate.
The surface treatment is preferably a discharge treatment in an atmosphere in which a reactive organic compound is mixed with an inert gas.
The melt-processable fluororesin is at least one fluorine-containing copolymer selected from the group consisting of tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymers and tetrafluoroethylene-hexafluoropropylene. It is preferable.

In the metal-clad laminate of the present invention, the metal layer and the base material are firmly bonded, and exhibit excellent electrical characteristics.

It is a cross-sectional schematic diagram of an example of the metal-clad laminated body of this invention.

The metal-clad laminate of the present invention comprises a base material layer (A), a layer (B) made of a melt-processable fluororesin provided on both surfaces of the base material layer (A), and each of the above layers ( B) has a metal layer (C) provided thereon, and the layer (B) made of the melt-processable fluororesin has a surface that is in contact with the base material layer (A). A feature of the metal-clad laminate.
For this reason, the metal-clad laminate of the present invention is obtained by firmly bonding a metal layer and a base material layer through a layer made of a fluororesin. In addition, it exhibits excellent electrical characteristics.

In FIG. 1, the cross-sectional schematic diagram of an example of the metal-clad laminated body of this invention is shown. As shown in FIG. 1, a base material layer (A), a layer (B) made of a melt-processable fluororesin provided on both surfaces of the base material layer, and a layer provided on each of the layers (B) A metal layer (C) formed.
That is, the metal-clad laminate of the present invention comprises a metal layer (C) 1, a layer (B) 2 made of a melt-processable fluororesin, a base layer (A) 3, and a layer made of a melt-processable fluororesin ( B) 4 and the metal layer (C) 5 are laminated in this order.
Each layer is described in detail below.

<Base material layer (A)>
As a component which comprises a base material layer (A), a polyimide, a polyethylene terephthalate, a polyethylene naphthalate, a liquid crystal polymer etc. are mentioned, for example.
Especially, the base material layer (A) is preferably made of polyimide from the viewpoint of adhesiveness.

The base material layer (A) preferably has a thickness of 5 to 100 μm. As for the thickness of a base material layer (A), 7.5 micrometers or more are more preferable, 55 micrometers or less are more preferable, and 50 micrometers or less are still more preferable.

<Layer made of melt-processable fluororesin (B)>
The melt-processable fluororesin is a polymer (homopolymer or copolymer) having a repeating unit derived from at least one fluorine-containing ethylenic monomer, and is a polymer having melt processability.

The fluorine-containing ethylenic monomer is an olefinically unsaturated monomer having at least one fluorine atom. Specific examples of the fluorine-containing ethylenic monomer include tetrafluoroethylene [TFE], vinylidene fluoride [VdF], chlorotrifluoroethylene [CTFE], vinyl fluoride, hexafluoropropylene [HFP], hexafluoroisobutene. Formula (1):
CH ₂ = CX ¹ (CF ₂ ) _n X ² (1)
(Wherein, X ¹ is H or F, X ² is H, F or Cl, and n is an integer of 1 to 10), and perfluoro (alkyl vinyl ether) Can be mentioned.

Examples of the perfluoro (alkyl vinyl ether) [PAVE] include perfluoro (methyl vinyl ether) [PMVE], perfluoro (ethyl vinyl ether) [PEVE], perfluoro (propyl vinyl ether) [PPVE], and perfluoro ( Butyl vinyl ether) and the like.

The fluororesin may be a copolymer having the fluorine-containing ethylenic monomer unit and an ethylenic monomer unit having no fluorine.

The ethylenic monomer having no fluorine is preferably an ethylenic monomer having 5 or less carbon atoms from the viewpoint of good heat resistance and chemical resistance, specifically, ethylene, propylene, 1-butene. 2-butene, vinyl chloride, vinylidene chloride and the like.

Examples of the fluororesin include polytetrafluoroethylene [PTFE], polychlorotrifluoroethylene [PCTFE], ethylene [Et] -TFE copolymer [ETFE], Et-chlorotrifluoroethylene [CTFE] copolymer, CTFE. It is preferably at least one selected from the group consisting of -TFE copolymer, TFE-HFP copolymer [FEP], TFE-PAVE copolymer [PFA], and polyvinylidene fluoride [PVdF]. .
In particular, the fluororesin is more preferably at least one fluorine-containing copolymer selected from the group consisting of PFA and FEP.

PFA is a copolymer including polymerized units based on TFE (TFE units) and polymerized units based on PAVE (PAVE units).
In the PFA, PAVE is not particularly limited, and for example, the following general formula (1):
CF ₂ = CF-ORf ¹ (1)
(In the formula, Rf ¹ represents a perfluoro organic group.)
The perfluoro unsaturated compound represented by these is mentioned. In the present specification, the “perfluoro organic group” means an organic group in which all hydrogen atoms bonded to carbon atoms are substituted with fluorine atoms. The perfluoro organic group may have an etheric oxygen atom.

As the PAVE, for example, in the general formula (1), Rf ¹ is preferably a perfluoroalkyl group having 1 to 10 carbon atoms. The number of carbon atoms of the perfluoroalkyl group is more preferably 1 to 5.

The PAVE is selected from the group consisting of perfluoro (methyl vinyl ether) [PMVE], perfluoro (ethyl vinyl ether) [PEVE], perfluoro (propyl vinyl ether) [PPVE], and perfluoro (butyl vinyl ether). It is more preferably at least one, more preferably at least one selected from the group consisting of PMVE, PEVE and PPVE, and particularly preferably PPVE in terms of excellent heat resistance.

The PFA preferably has 1 to 10 mol% of PAVE units, and more preferably 3 to 6 mol% of PAVE units. The PFA preferably has a total of 90 to 100 mol% of TFE units and PAVE units with respect to all polymerized units.

The PFA may be a copolymer including TFE units, PAVE units, and polymerized units based on monomers copolymerizable with TFE and PAVE. As a monomer copolymerizable with TFE and PAVE, hexafluoropropylene, CX ¹ X ² = CX ³ (CF ₂ ) _n X ⁴ (wherein X ¹ , X ² and X ³ are the same or different. Represents a hydrogen atom or a fluorine atom, X ⁴ represents a hydrogen atom, a fluorine atom or a chlorine atom, and n represents an integer of 2 to 10.), CF ₂ ═CF—OCH _And alkyl perfluorovinyl ether derivatives represented by ^2- Rf ² (wherein Rf ² represents a perfluoroalkyl group having 1 to 5 carbon atoms). As a monomer copolymerizable with TFE and PAVE, hexafluoropropylene and CF ₂ ═CF—OCH ₂ —Rf ² (wherein Rf ² represents a perfluoroalkyl group having 1 to 5 carbon atoms). At least one selected from the group consisting of alkyl perfluorovinyl ether derivatives represented is preferable.

As the alkyl perfluorovinyl ether derivative, those in which Rf ² is a perfluoroalkyl group having 1 to 3 carbon atoms are preferable, and CF ₂ ═CF—OCH ₂ —CF ₂ CF ₃ is more preferable.

When PFA has polymerized units based on monomers copolymerizable with TFE and PAVE, PFA has 0 to 10 monomer units derived from monomers copolymerizable with TFE and PAVE. Preferably, the total amount of TFE units and PAVE units is 90 to 100 mol%. More preferably, the monomer units derived from monomers copolymerizable with TFE and PAVE are 0.1 to 10 mol%, and the total of TFE units and PAVE units is 90 to 99.9 mol%. . When there are too many copolymerizable monomer units, there exists a possibility that the adhesiveness of a layer (A) and a layer (B) and a layer (B) and a layer (C) may be inferior.

FEP is a copolymer containing polymerized units (TFE units) based on tetrafluoroethylene and polymerized units (HFP units) based on hexafluoropropylene.
FEP is not particularly limited, but a copolymer having a molar ratio of TFE units to HFP units (TFE units / HFP units) of 70 to 99/30 to 1 is preferable. A more preferred molar ratio is 80 to 97/20 to 3. When there are too few TFE units, there exists a tendency for a mechanical physical property to fall, and when too much, melting | fusing point becomes high too much and there exists a tendency for a moldability to fall.

FEP has a monomer unit derived from a monomer copolymerizable with TFE and HFP in an amount of 0.1 to 10 mol%, and a total of 90 to 99.9 mol% of TFE units and HFP units. A polymer is also preferred. Examples of monomers copolymerizable with TFE and HFP include PAVE and alkyl perfluorovinyl ether derivatives.

The content of each monomer in the copolymer described above can be calculated by appropriately combining NMR, FT-IR, elemental analysis, and fluorescent X-ray analysis depending on the type of monomer.

The fluororesin preferably has a carbonyl group-containing functional group at the main chain terminal. When the fluororesin (for example, PFA) has a carbonyl group-containing functional group at the end of the main chain, the layer (A) and the layer (B), and the layer (B) and the layer (C) are bonded more firmly. be able to. The fluororesin may have a carbonyl group-containing functional group at both ends of the main chain or only at one end. The fluororesin preferably has no carbonyl group-containing functional group in the side chain.

Examples of the carbonyl group-containing functional group include a carbonate group, a carboxylic acid halide group (halogenoformyl group), a formyl group, a carboxyl group, an ester group [—C (═O) O—], an acid anhydride group [—C (= O) O—C (═O) —], isocyanate group, amide group, imide group [—C (═O) —NH—C (═O) —], urethane group [—NH—C (═O ) O—], carbamoyl group [NH ₂ —C (═O) —], carbamoyloxy group [NH ₂ —C (═O) O—], ureido group [NH ₂ —C (═O) —NH—] , An oxamoyl group [NH ₂ —C (═O) —C (═O) —] and the like, which are part of the chemical structure.
A hydrogen atom bonded to a nitrogen atom such as an amide group, an imide group, a urethane group, a carbamoyl group, a carbamoyloxy group, a ureido group, or an oxamoyl group may be substituted with a hydrocarbon group such as an alkyl group.
The carbonyl group-containing functional group includes a carboxyl group, an ester group, and an isocyanate group because of excellent adhesion between the layer (A) and the layer (B) and excellent adhesion between the layer (B) and the layer (C). At least one selected from the group consisting of groups is preferred, and among these, a carboxyl group is particularly preferred.

From the viewpoint of adhesiveness, the fluororesin preferably has 5 or more carbonyl group-containing functional groups per 10 ⁶ main chain carbon atoms. The carbonyl group-containing functional group is more preferably 20 or more per 10 ⁶ main chain carbon atoms, more preferably 50 or more, particularly preferably 80 or more, and particularly preferably 100 or more, because the adhesion is more excellent. preferable.

The melt-processable fluororesin preferably has a melt flow rate (MFR) of 20 g / 10 min or more. The MFR is more preferably 30 g / 10 min or more, and more preferably 60 g / 10 min or more, because the adhesiveness is more excellent. The upper limit of MFR is, for example, 100 g / 10 minutes.
The MFR is a value that can be measured under conditions of a temperature of 372 ° C. and a load of 5.0 kg in accordance with ASTM D3307.

The melting point of the melt-processable fluororesin is preferably 310 ° C. or lower. Since melting | fusing point is more excellent in adhesiveness, 307 degrees C or less is more preferable, and 305 degrees C or less is still more preferable. Moreover, 300 degreeC or more is preferable and, as for melting | fusing point, 302 degreeC or more is more preferable.
The melting point is a temperature corresponding to a melting peak when the temperature is raised at a rate of 10 ° C./min using a DSC (Differential Scanning Calorimetry) apparatus.

The melt-processable fluororesin layer (B) may contain an inorganic pigment, a filler, an adhesion promoter, an antioxidant, a lubricant, a dye, and the like. The inorganic pigment is preferably stable when it is molded, and examples thereof include titanium, iron oxide, and carbon powder.

The melt-processable layer (B) made of a fluororesin is a layer provided on both surfaces of the base material layer (A), and any of the surfaces in contact with the base material layer (A) is surface-treated. It is a thing. By performing the surface treatment, the adhesiveness to the substrate can be made stronger and the electrical properties can be made excellent.

The surface treatment is preferably a discharge treatment in an atmosphere in which a reactive organic compound is mixed with an inert gas.

Examples of the inert gas include nitrogen gas, helium gas, and argon gas.
The reactive organic compound is a polymerizable or non-polymerizable organic compound containing an oxygen atom, for example, vinyl esters such as vinyl acetate and vinyl formate; acrylic acid esters such as glycidyl methacrylate; vinyl ethyl ether, vinyl Ethers such as methyl ether and glycidyl methyl ether; Carboxylic acids such as acetic acid and formic acid; Alcohols such as methyl alcohol, ethyl alcohol, phenol, and ethylene glycol; Ketones such as acetone and methyl ethyl ketone; Carboxes such as ethyl acetate and ethyl formate Acid esters; acrylic acids such as acrylic acid and methacrylic acid; and the like. Of these, the modified surface is less likely to be deactivated (long life), and is easy to handle from the viewpoint of safety, vinyl esters, acrylate esters or ketones are preferable, especially vinyl acetate or Glycidyl methacrylate is preferred.

The concentration of the reactive organic compound varies depending on the type of organic compound, the type of fluororesin, etc., but is preferably 0.1 to 3.0% by volume, more preferably 0.1 to 1.0% by volume.

The discharge treatment can be performed in the above atmospheric gas by various discharge methods such as corona discharge and glow discharge. However, it is not necessary to depressurize the inside of the apparatus. In some respects, corona discharge treatment is preferred because it is less affected by atmospheric gas in the vicinity of the electrode and stable discharge can be easily obtained.

The discharge condition is preferably a charge density of 0.3 to 9.0 W · sec / cm ² from the viewpoint of processing efficiency. The charge density is more preferably 3.0 W · sec / cm ² or less.

The thickness of the melt-processable fluororesin layer (B) varies depending on the application, but is preferably 5 to 100 μm.
The thickness of the layer (B) is more preferably 10 μm or more, further preferably 12.5 μm or more, more preferably 75 μm or less, and further preferably 50 μm or less.

<Metal layer (C)>
The metal constituting the metal layer (C) is preferably at least one selected from the group consisting of copper, stainless steel, aluminum, iron, and alloys thereof. When the metal is as described above, the layer (B) and the layer (C) are firmly bonded. In view of excellent electrical characteristics, the metal is more preferably at least one selected from the group consisting of copper and aluminum, and more preferably copper.
Examples of the stainless steel include austenitic stainless steel, martensitic stainless steel, and ferritic stainless steel.

The metal layer (C) may be a layer formed by sputtering, vacuum deposition, or the like, or may be formed by bonding a metal foil.
From the viewpoint of simplicity in manufacturing a wiring board, those formed by bonding metal foils are preferable, and those formed by bonding the metal foils by hot pressing are more preferable.

The thickness of the metal layer (C) is preferably 5 to 200 μm. As for the thickness of a metal layer (C), 12 micrometers or more are more preferable, 50 micrometers or less are more preferable, and 25 micrometers or less are still more preferable.

It does not specifically limit as a method to manufacture the metal-clad laminated body of this invention, What is necessary is just to manufacture by a well-known method. For example, after each layer is formed, the layers may be laminated and bonded to obtain a laminated body, or a laminated body of a metal layer (C) and a layer (B) made of a melt-processable fluororesin. The laminate may be formed by bonding the laminate and the substrate.

Examples of the method for forming the layer (B) made of a melt-processable fluororesin include a method of forming a film by molding the melt-processable fluororesin or a composition containing the fluororesin. The said layer (B) is obtained by giving the above-mentioned surface treatment to one surface of the obtained film.
Examples of the molding method include melt extrusion molding, solvent casting, and spraying.
The composition containing a melt-processable fluororesin may contain an organic solvent, a curing agent, etc., and if necessary, a curing accelerator, a pigment dispersant, an antifoaming agent, a leveling agent, a UV absorption. Additives such as an agent, a light stabilizer, a thickener, an adhesion improver, and a matting agent may be included.
Examples of the curing agent include isocyanate, melamine resin, and phenol resin.
Examples of the curing accelerator include conventionally known tin-based, other metal-based, organic acid-based, amino-based, and phosphorus-based curing accelerators.
The composition containing the melt-processable fluororesin may be prepared by a known method.

A laminate of a metal layer (C) and a layer (B) made of a melt-processable fluororesin is applied by applying the composition containing the melt-processable fluororesin onto a metal foil and drying or heating. Obtainable.
Examples of the method for applying the melt-processable fluororesin-containing composition include, for example, brush coating, dip coating, spray coating, comma coating, knife coating, die coating, lip coating, roll coater coating, curtain coating, and the like. A method is mentioned.

In addition, a film (layer (B)) made of a melt-processable fluororesin is formed first, and a metal layer is formed on the film using a vacuum coating method such as vapor deposition, sputtering, or ion plating, By forming a metal layer by a wet plating method such as electroless plating or electroplating, a laminate of the metal layer (C) and a layer (B) made of a melt-processable fluororesin may be obtained.
In the laminate, the surface treatment is performed on the surface on the layer (B) side.

Using two laminates of the metal layer (C) obtained above and a layer (B) made of a melt-processable fluororesin, a base material layer (A ) Are sandwiched and bonded, and the metal-clad laminate of the present invention can be manufactured.

Examples of the method of bonding each layer or laminate include a method in which the formed layer or laminate is stacked and then thermocompression bonded by a hot press. The thermocompression bonding temperature is preferably 300 to 350 ° C.
The pressure for thermocompression bonding is preferably from 0.1 to 30 MPa, more preferably from 1 to 10 MPa.

The metal-clad laminate of the present invention can be formed into a printed circuit board by etching the surface of the metal layer and providing a pattern circuit. That is, this invention is also a printed circuit board provided with the pattern circuit obtained by etching the surface of the metal layer (C) of the said metal-clad laminated body.
The pattern circuit may be formed on one or both of the two metal layers.
The printed circuit board may include a coverlay film on the printed circuit board.

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

Each numerical value in Examples and the like was measured by the following method.

(Polymer composition)
^It was measured by ¹⁹ F-NMR analysis.

(Number of functional groups containing carbonyl group)
The sample was compression molded to 350 ° C. to produce a film having a thickness of 0.25 to 0.3 mm. This film was scanned 40 times with a Fourier transform infrared spectrometer [FT-IR] (trade name: Model 1760X, manufactured by PerkinElmer), analyzed to obtain an infrared absorption spectrum, and completely fluorinated. A difference spectrum from the base spectrum in which no end group was present was obtained. From the absorption peak of the carbonyl group appearing in this difference spectrum, the number N of carbonyl group-containing functional groups per 1 × 10 ⁶ carbon atoms in the sample was calculated according to the following formula.
N = I × K / t
I: Absorbance K: Correction coefficient t: Film thickness (mm)
For reference, Table 1 shows the absorption frequency, molar extinction coefficient, and correction coefficient for the carboxyl group, which is one of the carbonyl group-containing functional groups. The molar extinction coefficient is determined from FT-IR measurement data of a low molecular weight model compound.

(MFR)
Using a melt indexer (manufactured by Toyo Seiki Seisakusho), in accordance with ASTM D3307, the mass of the polymer flowing out per unit time (10 minutes) from a nozzle with a diameter of 2 mm and a length of 8 mm under a temperature of 372 ° C. under a 5 kg load ( g) was measured.

(Melting point)
The melting point is a temperature corresponding to a melting peak when the temperature is raised at a rate of 10 ° C./min using a differential scanning calorimetry (DSC) apparatus.

Reference example 1
PFA (composition TFE / PPVE = 97.2 / 2.8 (mol%), MFR: 70.2 g / 10 min, melting point: 290 ° C., main chain terminal carboxyl group number: 115 per 10 ⁶ main chain carbon atoms) A film (thickness 25 μm, 10 × 10 cm) and a copper foil (thickness 50 μm, 10 × 10 cm) are laminated, and the vacuum heat press machine is applied at 310 ° C., preheating 60 seconds, pressing force 10.2 MPa, pressing time 120 seconds. Then, a metal-clad laminate (sample A) was produced by hot pressing.
Table 2 shows sample preparation conditions.

Reference example 2
PFA (composition TFE / PPVE = 97.9 / 2.1 (mol%), MFR: 24.7 g / 10 min, melting point: 294 ° C., number of main chain terminal carboxyl groups: 80 per 10 ⁶ main chain carbon atoms) A film (thickness 25 μm, 10 × 10 cm) and a copper foil (thickness 50 μm, 10 × 10 cm) are laminated, and the vacuum heat press machine is applied at 310 ° C., preheating 60 seconds, pressing force 10.2 MPa, pressing time 120 seconds. Then, a metal-clad laminate (sample B) was produced by hot pressing.
Table 2 shows sample preparation conditions.

Reference example 3
PFA (TFE / PPVE = 98.5 / 1.5 (mol%), MFR: 14.8 g / 10 min, melting point: 305 ° C., number of main chain terminal carboxyl groups: 21 per 10 ⁶ main chain carbon atoms) film (Thickness 25 μm, 10 × 10 cm) and copper foil (thickness 50 μm, 10 × 10 cm) are laminated, and 310 ° C., preheating 60 seconds, pressurizing pressure 10.2 MPa, pressurization time 120 seconds with a vacuum heat press. A metal-clad laminate (sample C) was produced by hot pressing.
Table 2 shows sample preparation conditions.

Reference example 4
PFA (TFE / PPVE = 98.5 / 1.5 mol%, MFR: 2.2 g / 10 min, melting point: 307 ° C., main chain terminal carboxyl group number: 9 per 10 ⁶ main chain carbon atoms) film (thickness) 25 [mu] m, 10 * 10 cm) and copper foil (thickness 50 [mu] m, 10 * 10 cm) are laminated and hot pressed with a vacuum heat press machine at 310 [deg.] C., preheating 60 seconds, pressurizing pressure 10.2 MPa, pressurization time 120 seconds. As a result, a metal-clad laminate (sample D) was produced.
Table 2 shows sample preparation conditions.

Reference Example 5
PFA (TFE / PPVE = 97.9 / 2.1 (mol%), MFR: 24.7 g / 10 min, melting point: 294 ° C., number of main chain terminal carboxyl groups: 80 per 10 ⁶ main chain carbon atoms) surface A treated film (thickness 50 μm, 10 × 10 cm) and a polyimide (PI) film (thickness 50 μm, 10 × 10 cm) are laminated in the order of PFA / PI / PFA, 310 ° C., preheating 60 seconds, applied pressure 10.2 MPa, A laminate (sample E) was produced by hot pressing with a vacuum heat press with a pressurization time of 120 seconds.
The surface treatment was performed by corona discharge of the PFA film in an atmosphere in which a reactive organic compound was mixed with nitrogen gas.
Table 2 shows sample preparation conditions.

Comparative Example 1
In Reference Example 5, the PFA film and the PI film were laminated in the order of PFA / PI / PFA in the same manner as in Reference Example 5 except that a PFA film not subjected to surface treatment was used, and 310 ° C., preheating 60 seconds. A laminate (sample F) was produced by hot pressing with a vacuum heat press at 10.2 MPa and a pressurization time of 120 seconds.
Table 2 shows sample preparation conditions.

(Peel test)
Using the samples A to D obtained above, the integral strength, maximum average, and maximum point of the peel strength were determined by the following method to evaluate the adhesive strength.

(Integral average)
The load in the measurement section was averaged.
(Maximum average)
It calculated | required as an average value load of the maximum point in a measurement area.
(Maximum point)
The maximum load point in the measurement section was obtained.
Table 3 shows the measurement results.

(Peel test)
Using sample E and sample F obtained above, the integral strength of peel strength and the maximum point were determined by the following method to evaluate the adhesive strength.

(Integral average)
The load in the measurement section was averaged.
(Maximum point)
The maximum load point in the measurement section was obtained.
Table 4 shows the measurement results.

Comparative Example 2
A polyimide resin film (trade name “Kapton V”, manufactured by Toray DuPont, thickness 48 μm) was used as sample G.

(Electrical characteristics)
Using a network analyzer, the change in resonance frequency and Q value of sample E and sample G (trade name “Kapton V”, polyimide resin film, manufactured by Toray DuPont Co., Ltd.) prepared above is measured with a cavity resonator. Tan δ at 12 GHz was calculated according to the following equation. The cavity resonator method is based on Prof. Kobayashi, Saitama University [Non-destructive measurement of complex permittivity of dielectric flat plate material by cavity resonator method MW87-53].
tan δ = (1 / Qu) × {1+ (W ₂ / W ₁ )} − (Pc / ωW ₁ )

However, the symbols in the formula are as follows.
D: Cavity resonator diameter (mm)
M: Length of one side of cavity resonator (mm)
L: Sample length (mm)
c: Speed of light (m / s)
Id: Attenuation (dB)
F ₀ : Resonance frequency (Hz)
F ₁ : upper frequency (Hz) at which the attenuation from the resonance point is 3 dB
F ₂ : Lower frequency (Hz) at which the attenuation from the resonance point is 3 dB
ε ₀ : dielectric constant of vacuum (H / m)
ε _r : relative permittivity of sample μ ₀ : permeability of vacuum (H / m)
Rs: Effective surface resistance considering the surface roughness of the conductor cavity (Ω)
J ₀ : -0.402759+
J ₁ : 3.83171
The results are shown in Table 5.

Example 1
PFA (composition TFE / PPVE = 97.9 / 2.1 (mol%), MFR: 24.7 g / 10 min, melting point) having a single-side surface-treated on both sides of a polyimide resin film (thickness 25 μm, manufactured by Toray DuPont) : 294 ° C., number of main chain terminal carboxyl groups: 80 per 10 ⁶ main chain carbon atoms) A film (thickness 25 μm, 10 × 10 cm) is stacked, and a copper foil (thickness 50 μm, 10 × 10 cm) is applied to the untreated side of the PFA film. And a metal-clad laminate (sample H) was produced by hot pressing with a vacuum heat press at 310 ° C., preheating 60 seconds, pressurizing pressure 10.2 MPa, pressing time 120 seconds.

The curl properties of the metal-clad laminate obtained in Example 1 and the laminate (Sample F) obtained in Comparative Example 1 were evaluated.

(Curl property)
The laminate was cut into 50 mm × 50 mm, and the curl generated at that time and the curl generated after heating in an electric furnace at 200 ° C. for 10 minutes were evaluated by measuring the radius of curvature of the laminate. The evaluation criteria are shown below. The evaluation results are shown in Table 6.
A: Curvature radius is 80 mm or more B: Curvature radius is 50 mm or more and less than 80 mm B: Curvature radius is 20 mm or more and less than 50 mm X: Curvature radius is less than 20 mm

Since the metal-clad laminate of the present invention has a strong adhesion between the metal layer and the base material and exhibits excellent electrical characteristics, it can be suitably used for various electric devices, electronic devices, communication devices, and the like. .

1, 5

Metal layer

2, 4 Layer 3 made of melt-processable fluororesin 3 Base material layer

Claims

A base material layer (A);
A layer (B) comprising a melt-processable fluororesin provided on both surfaces of the base material layer;
Each having a metal layer (C) provided on the layer (B) made of melt-processable fluororesin,
The layer (B) made of the melt-processable fluororesin has a surface that is in contact with the base material layer (A) and is surface-treated.
The metal-clad laminate according to claim 1, wherein the surface treatment is a discharge treatment in an atmosphere in which a reactive organic compound is mixed with an inert gas.
The melt-processable fluororesin is a tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer and at least one fluorine-containing copolymer selected from the group consisting of tetrafluoroethylene-hexafluoropropylene. Item 3. A metal-clad laminate according to item 1 or 2.
A printed circuit board provided with the pattern circuit obtained by etching the surface of the metal layer (C) of the metal-clad laminated body of Claim 1, 2, or 3.