JP2022035805A - Method for manufacturing laminated plate and laminated plate - Google Patents

Abstract

To provide a laminated plate which prevents or suppresses the occurrence of wrinkles and a method for manufacturing the same.SOLUTION: There is provided a method for manufacturing a laminated plate in which a polymer film having a surface containing a tetrafluoroethylene-based polymer and a thermoplastic aromatic polymer and a metal substrate are arranged so that the surface is in contact with the metal substrate and the polymer film and the metal substrate are thermally press-bonded at a temperature lower than the glass transition point of the aromatic polymer to obtain a laminated plate. In addition, the laminated plate has a long metal layer and a long polymer layer which is joined to the metal layer and contains a tetrafluoroethylene-based polymer and a thermoplastic aromatic polymer on the surface of the metal layer side and the maximum height undulation Wz along a short direction of a surface opposite to the polymer layer of the metal layer is 100 μm or less.SELECTED DRAWING: None

Description

The present invention is a method for manufacturing a laminated board, and a long method for producing a laminated board, in which a polymer film containing a tetrafluoroethylene polymer and a thermoplastic aromatic polymer and a metal substrate are thermally pressure-bonded at a predetermined temperature to obtain a laminated board. The present invention relates to a laminated board having a metal layer and a long polymer layer bonded to the metal layer, and preventing or suppressing the occurrence of wrinkles on the surface of the metal layer opposite to the polymer layer.

Tetrafluoroethylene polymers have excellent physical properties such as releasability, electrical insulation, water and oil repellency, chemical resistance, weather resistance, and heat resistance, and various molded products (impregnated base material, supported base material, etc.) It can be used to form a layered base material, etc.).
In Patent Document 1, a resin film containing a tetrafluoroethylene polymer is heat-bonded to a metal foil, and then a heat-resistant resin film is heat-bonded to the resin film to obtain a laminated board, and the obtained laminated board is further processed. Then, a method for manufacturing a flexible printed substrate has been proposed.

International Publication 2016/10497

However, according to the study by the present inventors, since the tetrafluoroethylene polymer has a large linear expansion coefficient, when the resin film is thermally pressure-bonded to a metal foil, depending on the conditions and the like, the resin film (polymer film) may be used. There is a problem that wrinkles are likely to occur in the metal foil due to the difference in the thermal expansion rate between the metal foil and the metal foil (metal substrate).
As a result of further studies to solve the above problems, the present inventors added a thermoplastic aromatic polymer to the polymer film, and formed the polymer film and the metal substrate at a temperature lower than the glass transition point of the aromatic polymer. It was found that wrinkles can be prevented or suppressed from occurring on the laminated board (metal substrate) by thermal crimping.

The present invention has been made based on such findings, and an object thereof is to provide a laminated board in which wrinkles are prevented or suppressed, and a method for producing the same.

The present invention has the following aspects.
<1> A polymer film having a surface containing a tetrafluoroethylene-based polymer and a thermoplastic aromatic polymer and a metal substrate are arranged so that the surface is in contact with the metal substrate, and the glass transition of the aromatic polymer is performed. A method for manufacturing a laminated board, wherein the polymer film and the metal substrate are thermally pressure-bonded at a temperature lower than the point to obtain a laminated board.
<2> The production method of <1>, wherein a laminated plate is obtained by thermocompression bonding the polymer film and the metal substrate at a temperature 40 to 70 ° C. lower than the glass transition point of the aromatic polymer.
<3> The method for producing <1> or <2>, wherein the glass transition point of the aromatic polymer is 300 to 350 ° C.
<4> Any one of <1> to <3>, wherein the aromatic polymer is at least one selected from the group consisting of aromatic polyimide, aromatic polymaleimide, aromatic polyphenylene ether, and aromatic styrene elastomer. Production method.
<5> The manufacturing method according to any one of <1> to <4>, wherein the temperature at the time of thermocompression bonding is 250 to 300 ° C.
<6> The polymer film includes a surface layer having the surface, a support layer that supports the surface layer and contains a base polymer, and a glass transition point of the aromatic polymer and a glass transition point of the base polymer. The production method according to any one of <1> to <5>, wherein the absolute value of the difference from the above is 20 ° C. or less.
<7> The production method of <6>, wherein the glass transition point of the base polymer is 230 to 340 ° C.
<8> The method for producing <6> or <7>, wherein the base polymer is an aromatic polyimide.
<9> The production method according to any one of <1> to <8>, wherein the tetrafluoroethylene polymer is a tetrafluoroethylene polymer having a melting temperature of 260 to 320 ° C.
<10> The tetrafluoroethylene-based polymer contains a unit based on perfluoro (alkyl vinyl ether) and has a polar functional group, and the tetrafluoroethylene-based polymer has 2 units based on perfluoro (alkyl vinyl ether) for all units. The production method according to any one of <1> to <9>, which is at least one selected from the group consisting of tetrafluoroethylene-based polymers containing 0.0 to 5.0 mol% and having no polar functional group.
<11> The production method according to any one of <1> to <10>, wherein the polymer film and the metal substrate are each long.
<12> The manufacturing method of <11>, wherein in the laminated board, the maximum height waviness Wz along the lateral direction of the surface of the metal substrate opposite to the polymer film is 100 μm or less.
<13> The production method according to any one of <1> to <12>, wherein the peel strength between the metal substrate and the polymer film in the laminated board is 10 N / cm or more.
<14> A long metal layer and a long polymer layer bonded to the metal layer and containing a tetrafluoroethylene-based polymer and a thermoplastic aromatic polymer on the surface on the metal layer side are provided. A laminated plate having a maximum height undulation Wz of 100 μm or less along the lateral direction of the surface of the metal layer opposite to the polymer layer.
<15> The laminated board of <14>, wherein the peel strength between the metal layer and the polymer layer is 10 N / cm or more.

According to the present invention, there is provided a laminated board in which the occurrence of wrinkles is prevented or suppressed.

The following terms have the following meanings.
The "average particle size (D50)" is a volume-based cumulative 50% diameter of the object (powder or inorganic filler) determined by the laser diffraction / scattering method. That is, the particle size distribution of the object is measured by the laser diffraction / scattering method, the cumulative curve is obtained with the total volume of the group of particles of the object as 100%, and the particles at the point where the cumulative volume is 50% on the cumulative curve. The diameter.
“D90” is the volume-based cumulative 90% diameter of the object, which is similarly measured.
The "melting temperature (melting point)" is the temperature corresponding to the maximum value of the melting peak of the polymer measured by the differential scanning calorimetry (DSC) method.
The "glass transition point (Tg)" is a value measured by analyzing a polymer by a dynamic viscoelasticity measurement (DMA) method.
The "yield strength" means the stress at which the relationship between the strain and the stress becomes unproportionate when the strain becomes large, and the phenomenon that the strain remains even if the stress is removed starts to occur. According to ASTM D882, the tensile elastic modulus of the support layer It is specified by the value of "stress at 5% strain" when the rate is measured.
"Resistant plastic deformation" means a property in which the stress increases when the support layer is plastically deformed, or a property in which the stress required when the support layer is plastically deformed is large. It is specified by the value of "stress at 15% strain" when the tensile modulus is measured.
The "tensile elastic modulus of the film" is a value measured at a measurement frequency of 10 Hz using a wide-area viscoelasticity measuring device.
The "ten-point average roughness (Rzjis) of the surface of the metal foil (metal substrate)" is a value specified in Annex JA of JIS B 0601: 2013.
The "maximum height swell Wz" is a value on the outer surface of the laminated board measured according to JIS B 0601: 2013 (ISO 4287: 1997, Amd. 1: 2009).
The "unit" in the polymer may be an atomic group formed directly from the monomer, or may be an atomic group in which a part of the structure is converted by treating the obtained polymer by a predetermined method. The unit based on the monomer A contained in the polymer is also simply referred to as "monomer A unit".

The production method of the present invention (hereinafter, also referred to as “this method”) is described as a tetrafluoroethylene polymer (hereinafter, also referred to as “F polymer”) and a thermoplastic aromatic polymer (hereinafter, also referred to as “AR polymer”). The polymer film and the metal substrate having a surface containing.) Are placed so that the surface is in contact with the metal substrate, and the polymer film and the metal substrate are thermally pressure-bonded at a temperature lower than the glass transition point of the AR polymer. It is a method of obtaining a laminated board.
Therefore, the obtained laminated board is a laminated body having a metal layer and a polymer layer bonded to the metal layer.
In such a laminated board, the generation of wrinkles on the outer surface (the surface opposite to the polymer layer of the metal layer) is prevented or suppressed. The reason is not always clear, but it is thought to be as follows.

In this method, the surface of the polymer film contains, in addition to the F polymer having a large linear expansion coefficient, an AR polymer having a linear expansion coefficient smaller than that of the F polymer. Therefore, the surface of the polymer film (contact surface with the metal substrate) is less likely to be deformed by heating and cooling during heating and cooling. Further, in this method, thermocompression bonding is performed at a temperature lower than the glass transition point of the AR polymer. Therefore, it is considered that the AR polymer highly functions as an adhesive component with the metal layer without being excessively softened when heated. As a result, the polymer film is thermocompression-bonded to the metal substrate in a state of excellent shape stability when heated, so that the surface of the polymer film is not easily deformed, and the shape of the surface of the polymer film is reflected and the polymer film is also deformed to the metal substrate. Is unlikely to occur.
As a result, it is considered that the occurrence of wrinkles on the outer surface of the laminated board (metal substrate) was prevented or suppressed.

The polymer film may contain an F polymer and an AR polymer on its surface. Therefore, the polymer film may be a single-layer film containing an F polymer and an AR polymer, and is a laminated film having a surface layer having the above surface and a support layer supporting the surface layer and containing a base polymer. There may be. A laminated film containing a base polymer having a low linear expansion coefficient in the support layer can suppress deformation due to heating to a higher degree.
The laminated film may have a surface layer on only one surface of the support layer, or may have a surface layer on both surfaces of the support layer. In the latter case, it is easier to prevent the occurrence of warping of the laminated film and, by extension, the occurrence of warping of the laminated board.

The F polymer in this method is a polymer containing a unit (TFE unit) based on tetrafluoroethylene (TFE).
The F polymer is preferably thermally meltable, and its melting temperature is preferably 260 to 320 ° C, more preferably 285 to 320 ° C. In this case, the F polymer and the AR polymer are more likely to be more uniformly distributed in the polymer film and the polymer layer.
The glass transition point (Tg) of the F polymer is preferably 75 to 125 ° C, more preferably 80 to 100 ° C.
The melt viscosity of the F polymer is preferably 1 × 10 ² to 1 × 10 ⁶ Pa · s at 380 ° C., more preferably 1 × 10 ³ to 1 × 10 ⁶ Pa · s.

F-polymers are based on polytetrafluoroethylene (PTFE), polymers containing TFE units and ethylene-based units, polymers containing TFE units and propylene-based units, TFE units and perfluoro (alkyl vinyl ether) (PAVE). Polymers containing units (PAVE units) (PFA), polymers containing TFE units and units based on hexafluoropropylene (FEP), polymers containing TFE units and units based on fluoroalkylethylene, TFE units and chlorotrifluoro Examples thereof include polymers containing a unit based on ethylene, preferably PFA or FEP, and more preferably PFA. The polymer may further contain units based on other comonomeres.
As the PAVE, CF ₂ = CFOCF ₃ , CF ₂ = CFOCF ₂ CF ₃ or CF ₂ = CFOCF ₂ CF ₂ CF ₃ (hereinafter, also referred to as “PPVE”) is preferable, and PPVE is more preferable.

The F polymer preferably has a polar functional group. In this case, the polymer film and the polymer layer tend to have excellent physical properties such as electrical properties and surface smoothness.
The polar functional group may be contained in the unit contained in the F polymer, or may be contained in the terminal group of the F polymer main chain. Examples of the latter F polymer include a polymer having a polar functional group as a terminal group derived from a polymerization initiator, a chain transfer agent and the like, and a polymer having a polar functional group prepared by plasma treatment or ionization line treatment.

As the polar functional group, a hydroxyl group-containing group, a carbonyl group-containing group and a phosphono group-containing group are preferable, a hydroxyl group-containing group and a carbonyl group-containing group are more preferable, and a carbonyl group-containing group is further preferable.
As the hydroxyl group-containing group, an alcoholic hydroxyl group-containing group is preferable, and —CF ₂ CH ₂ OH, —C (CF ₃ ) ₂ OH and 1,2-glycol group (—CH (OH) CH ₂ OH) are more preferable.
Examples of the carbonyl group-containing group include a carboxyl group, an alkoxycarbonyl group, an amide group, an isocyanate group, a carbamate group (-OC (O) NH ₂ ), an acid anhydride residue (-C (O) OC (O)-), and the like. An imide residue (-C (O) NHC (O)-etc.) and a carbonate group (-OC (O) O-) are preferable, and an acid anhydride residue is more preferable.

As the F polymer, a tetrafluoroethylene polymer containing 1.5 to 5.0 mol% of perfluoro (alkyl vinyl ether) -based units and 1.5 to 5.0 mol% of perfluoro (alkyl vinyl ether) -based units with respect to all units is preferable, and TFE units are preferable. And a polymer (1) containing PAVE units and having a polar functional group, or a polar functional group containing TFE units and PAVE units and containing 2.0 to 5.0 mol% of PAVE units with respect to all monomer units. The non-existent polymer (2) is more preferable. Since these polymers form microspherulites in the polymer film and polymer layer, the physical characteristics of the obtained polymer film and polymer layer are likely to be improved.

The polymer (1) has 90 to 99 mol% of TFE units, 0.5 to 9.97 mol% of PAVE units and 0.01 to 3 mol of units based on a monomer having a polar functional group with respect to all the units. %, It is preferable to contain each.
Further, as the monomer having a polar functional group, itaconic anhydride, citraconic anhydride and 5-norbornen-2,3-dicarboxylic acid anhydride (hereinafter, also referred to as “NAH”) are preferable.
Specific examples of the polymer (1) include the polymers described in International Publication No. 2018/16644.

The polymer (2) consists of only TFE units and PAVE units, and contains 95.0 to 98.0 mol% of TFE units and 2.0 to 5.0 mol% of PAVE units with respect to all the units. preferable.
The content of PAVE units in the polymer (2) is preferably 2.1 mol% or more, more preferably 2.2 mol% or more, based on all the units.
The fact that the polymer (2) does not have polar functional groups means that the number of polar functional groups possessed by the polymer is less than 500 per 1 × 10 ⁶ carbon atoms constituting the polymer main chain. Means. The number of the polar functional groups is preferably 100 or less, more preferably less than 50. The lower limit of the number of polar functional groups is usually 0.

The polymer (2) may be produced by using a polymerization initiator, a chain transfer agent or the like that does not generate a polar functional group as the terminal group of the polymer chain, and is derived from a polymer having a polar functional group (derived from the polymerization initiator). A polymer having a polar functional group at the terminal group of the polymer chain, etc.) may be fluorinated to be produced.
Examples of the fluorination treatment method include a method using fluorine gas (see JP-A-2019-194314).

The AR polymer in this method preferably has a glass transition point of 300 to 350 ° C, more preferably 315 to 335 ° C. In this case, even if the polymer film is a single-layer film, it is easy to sufficiently prevent or suppress deformation due to heating by reducing the linear expansion coefficient of the single-layer film as a whole.
The 5% weight loss temperature of the AR polymer is preferably 260 ° C. or higher, more preferably 300 ° C. or higher, still more preferably 320 ° C. or higher. The 5% weight loss temperature of the AR polymer is preferably 600 ° C. or lower. In the above range, it is easy to effectively suppress the roughening of the interface between the polymer layer and the metal layer in the laminated board due to the decomposition gas (air bubbles) of the AR polymer and the gas (air bubbles) due to by-products accompanying the reaction of the AR polymer itself.

AR polymers are thermoplastic. Due to the plasticity of such an AR polymer, the dispersibility in the polymer film is further improved, and a dense and uniform polymer layer is easily formed.
The AR polymer is preferably at least one selected from the group consisting of aromatic polyimide, aromatic maleimide, aromatic polyphenylene ether, aromatic styrene elastomer, and liquid crystal polyester, and aromatic polyimide is more preferable. Here, the thermoplastic polyimide means a polyimide that has been imidized and does not further undergo an imidization reaction.
When such an AR polymer is used, when the polymer film is a laminated film, not only the adhesion of the surface layer to the support layer is likely to be improved, but also the physical characteristics of the film (UV absorption, etc.) are likely to be improved.

Specific examples of AR polymers include the "HPC" series (manufactured by Hitachi Kasei Co., Ltd.), which is an aromatic polyamide-imide, the "Neoprim" series (manufactured by Mitsubishi Gas Chemical Company), which is an aromatic polyimide, and the "Spiceria" series (Somar). (Manufactured by), "Q-PILON" series (manufactured by PI Technology Research Institute), "WINGO" series (manufactured by Wingo Technology), "Tomid" series (manufactured by T & K TOKA), "KPI-MX" series (manufactured by Kawamura Sangyo) (Manufactured by Ube Industries, Ltd.) and "Yupia-AT" series (manufactured by Ube Industries, Ltd.) and the like.
As the aromatic polyimide which is an AR polymer, the aromatic polyimide described in the base film described later may be used.

Preferable embodiments of the F polymer and the AR polymer in the present method include an embodiment in which the melting temperature of the F polymer is 285 to 320 ° C. and the glass transition point of the AR polymer is 315 to 335 ° C.
In the above aspect, not only the F polymer and the AR polymer are uniformly dispersed in the polymer film to improve the film physical properties, but also the F polymer and the AR polymer are highly interacted with each other in a high temperature environment. , The heat resistance of the polymer film is likely to be improved.

In the polymer film (in the case of a laminated film, the surface layer), the content of the AR polymer with respect to the total content of the F polymer and the AR polymer is preferably 10% by mass or less, more preferably 7.5% by mass or less, and 5 More preferably, it is by mass or less. The content of the AR polymer is preferably 0.1% by mass or more.
If the respective contents of the F polymer and the AR polymer in the polymer film satisfy the above ratio and the content of the AR polymer is low with respect to the content of the F polymer, the AR polymer is highly contained in the F polymer in the polymer film. It is easy to form a dispersed state. As a result, the physical properties (electrical properties, low water absorption, etc.) based on the F polymer are highly likely to be exhibited in the polymer film. Further, in the laminated board manufactured from such a polymer film, wrinkles are less likely to occur, and the peel strength of the laminated board is likely to be improved. When the polymer film is a laminated film, the adhesiveness between the support layer and the surface layer is likely to be improved, and warpage and peeling of the laminated film are unlikely to occur.

It is preferable that polar functional groups are present on the surface of the polymer film (the surface containing the F polymer and the AR polymer). If the polar functional group is present on the surface of the polymer film, the adhesiveness of the surface is increased, so that the adhesive strength with the metal substrate can be improved. In addition, the effect of reducing the linear expansion coefficient of the polymer film can be expected.
The polar functional group present on the surface of the polymer film is preferably a hydroxyl group-containing group or a carbonyl group-containing group.
As a method for allowing a polar functional group to exist on the surface of the polymer film, a method using an F polymer or an AR polymer having a polar functional group, corona discharge treatment, plasma treatment, UV ozone treatment, and excima on the surface of the polymer film. A method of introducing a polar functional group by performing surface treatment such as treatment, chemical etching, or silane coupling treatment can be adopted.

The corona discharge treatment is preferably performed in the presence of a flammable gas (vinyl acetate or the like) from the viewpoint of efficiently introducing a polar functional group.
Examples of the plasma irradiation device in plasma processing include a high frequency induction method, a capacitively coupled electrode method, a corona discharge electrode-plasma jet method, a parallel plate type, a remote plasma type, an atmospheric pressure plasma type, and an ICP type high density plasma type. ..
The gas used for the plasma treatment is preferably a rare gas, a hydrogen gas or a nitrogen gas. Specific examples of such a gas include argon gas, a mixed gas of hydrogen gas and nitrogen gas, and a mixed gas of hydrogen gas, nitrogen gas and argon gas.
Further, the polymer film may be subjected to an annealing treatment to adjust its residual stress. The conditions for the annealing treatment are preferably a temperature of 120 to 180 ° C., a pressure of 0.005 to 0.015 MPa, and a time of 30 to 120 minutes.

When the polymer film is a laminated film, the absolute value of the difference between the glass transition point of the AR polymer contained in the surface layer and the glass transition point of the base polymer contained in the support layer is preferably 20 ° C. or lower, preferably 10 ° C. or lower. Is more preferable. The absolute value of the difference between the glass transition points may be 0 ° C. In this case, since the glass transition point of the AR polymer and the glass transition point of the base polymer are close to each other, the polymer film as a whole is less likely to be deformed by heating.
The specific value of the glass transition point of the base polymer contained in the support layer is preferably 230 to 340 ° C, more preferably 250 to 320 ° C. In this case, the degree of deformation of the support layer due to heating is sufficiently low.

If the absolute value of the difference in the glass transition point and the specific value of the glass transition point of the base polymer satisfy the above ranges, the occurrence of wrinkles on the outer surface of the obtained laminated plate can be more reliably prevented or suppressed.
The base polymer contained in the support layer is preferably aromatic polyimide. If an aromatic polyimide is used, the degree of deformation of the support layer due to heating tends to be lower.
The content of the base polymer in the support layer is preferably 80% by mass or more, more preferably 90% by mass or more. The content may be 100% by mass.

The imide group density of the aromatic polyimide as the base polymer is preferably 0.20 to 0.35. When the imide group density is not more than the above upper limit value, the water absorption rate of the support layer becomes lower, and it is easy to suppress the change in the dielectric property of the polymer film. When the imide group density is at least the above lower limit value, the imide group functions as a polar group, and not only the adhesion between the support layer and the surface layer is further improved, but also the water absorption rate tends to be significantly reduced.
Further, if the imide group density is within the range, wrinkles are less likely to occur in the polymer film. Such wrinkles are less likely to occur when the glass transition point of the aromatic polyimide in the support layer is high.

The imide group density is a value obtained by dividing the molecular weight (140.1) per unit of the imide group portion by the molecular weight per unit of the polyimide in the polyimide obtained by imidizing the polyimide precursor. For example, a polyimide precursor consisting of two components, 1 mol of pyromellitic dianhydride (molecular weight: 218.1) and 1 mol of 3,4'-oxydianiline (molecular weight: 200.2), was imidized. The imide group density of polyimide (molecular weight per unit: 382.2) is 0.37, which is the value obtained by dividing 140.1 by 382.2.

Examples of the aromatic polyimide include a polyimide obtained by reacting a diamine with a carboxylic acid dianhydride to synthesize a polyamic acid, and imidizing the polyamic acid by a thermal imidization method or a chemical imidization method.
Examples of the solvent for synthesizing the polyamic acid include N, N-dimethylformamide, N, N-dimethylacetamide, and N-methyl-2-pyrrolidone.

As the diamine, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenylmethane, 4,4'-oxydianiline, 3,3'-oxydianiline, 3,4'-oxydianiline, 4, 4'-diaminodiphenyldiethylsilane, 4,4'-diaminodiphenylsilane, 1,4-diaminobenzene (p-phenylenediamine), 4,4'-bis (4-aminophenoxy) biphenyl, 4,4'-bis (3-Aminophenoxy) Biphenyl, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 1,3 -Bis (3-aminophenoxy) benzene, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2-bis {4- ( 4-Aminophenoxy) phenyl} propane, 3,3'-dihydroxy-4,4'-diamino-1,1'-biphenyl, 2,4-diaminotoluene and the like. These diamine components may be used alone or in combination of two or more.

Examples of the carboxylic acid dianhydride include pyromellitic acid dianhydride, 3,3'4,4'-biphenyltetracarboxylic acid dianhydride, 2,2', 3,3'-biphenyltetracarboxylic acid dianhydride, and the like. 2,3,3', 4'-biphenyltetracarboxylic acid dianhydride, 3,3', 4,4'-biphenyl ether tetracarboxylic acid dianhydride, 2,2-bis (3,4-dicarboxyphenyl) ) Propane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis ( 3,4-dicarboxyphenyl) ethane dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 3,3', 4, 4'-benzophenone tetracarboxylic acid dianhydride, 2,3,2', 3'-benzophenone tetracarboxylic acid dianhydride, 2,3,3', 4'-benzophenone tetracarboxylic acid dianhydride, 1,3 -Bis (3,4-dicarboxyphenyl) -1,1,3,3-tetramethyldicyclohexanedianhydride, 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropanedianhydride, 2 , 2-Bis [4- (3,4-dicarboxyphenoxy) phenyl] hexafluoropropane dianhydride, 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] propane dianhydride. Be done. These dicarboxylic acid components may be used alone or in combination of two or more.

The total number of moles of oxygen atoms derived from the ether bond contained in the diamine and the carboxylic acid dianhydride is preferably 35 to 70%, preferably 45 to 65%, based on the total number of moles of the diamine and the carboxylic acid dianhydride. Is more preferable. In this case, the flexibility of the polymer main chain of the aromatic polyimide is increased, the stackability of the aromatic ring is improved, and the adhesiveness between the support layer and the surface layer is further improved. Further, in this case, the UV processability of the polymer film is also improved.
An inorganic filler may be added to the support layer for the purpose of enhancing properties such as yield strength, resistance to plastic deformation, thermal conductivity, and loop stiffness. Examples of such an inorganic filler include silicon oxide, titanium oxide, aluminum oxide, silicon nitride, boron nitride, calcium hydrogen phosphate, and calcium phosphate.

The support layer in the laminated film preferably has a high yield strength. Specifically, the stress at 5% strain of the support layer is preferably 180 MPa or more, more preferably 210 MPa or more. The stress at 5% strain is preferably 500 MPa or less.
Further, the support layer is preferably non-plastically deformable. Specifically, the stress at 15% strain of the support layer is preferably 225 MPa or more, more preferably 245 MPa or more. The stress at 15% strain is preferably 580 MPa or less.
If the support layer has a high yield strength, particularly resistance to plastic deformation, the absolute value of the linear expansion coefficient of the laminated film can be easily lowered sufficiently, and the occurrence of warpage can be prevented more reliably.

The tensile elastic modulus of the support layer at 320 ° C. is preferably 0.2 GPa or more, more preferably 0.4 GPa or more. The tensile elastic modulus is preferably 10 GPa or less, and more preferably 5 GPa or less.
The laminated film in this case is excellent in handleability even if it is heated and cooled when it is processed. That is, when the tensile elastic modulus of the support layer is equal to or higher than the above lower limit, the shrinkage of the surface layer is effectively alleviated by the elasticity of the support layer during heating and cooling during processing, and wrinkles are less likely to occur in the laminated film. , The physical characteristics (surface smoothness, etc.) of the obtained laminated board are likely to be improved. This tendency becomes remarkable when the content of the F polymer in the surface layer and the thickness of the surface layer are large. Further, when the tensile elastic modulus of the support layer is not more than the above upper limit value, the flexibility of the laminated film is likely to be further increased.

In the laminated film, it is preferable that the support layer and the surface layer are in direct contact with each other. That is, it is preferable that the surface layer is directly formed (laminated) on the surface of the support layer without subjecting the surface treatment with a silane coupling agent, an adhesive or the like. In this case, the physical characteristics of the film are unlikely to deteriorate. According to the laminated film, due to the above-mentioned configuration, even if the support layer and the surface layer are in direct contact with each other, high adhesiveness is exhibited between the support layer and the surface layer.
The thickness of the polymer film (total thickness in the case of a laminated film) in this method is preferably 25 μm or more, more preferably 50 μm or more. The thickness is preferably 1000 μm or less, more preferably 200 μm or less.

When the laminated film has surface layers on both surfaces of the support layer, the ratio of the total thickness of the two surface layers to the thickness of the support layer is preferably 1 or more. The above ratio is preferably 3 or less. In this case, the physical properties of the base polymer in the support layer (high yield strength, resistance to plastic deformation, etc.) and the physical properties of the F polymer in the surface layer (low dielectric constant, electrical properties such as low dielectric loss tangent, low water absorption, etc.) are balanced. It is easy to express well. Further, even in a polymer film having a large ratio and a thick surface layer, warpage and peeling are easily suppressed. In particular, when the tensile elastic modulus of the support layer is equal to or higher than the above-mentioned lower limit value, this tendency tends to be remarkable.

Also, the thicknesses of the two polymer layers are preferably equal. In this case, since the linear expansion coefficients of the two polymer layers are closer to each other, the laminated film is less likely to be warped.
The dielectric constant of the polymer film is preferably 2.0 to 3.0. In this case, the laminated board of the present invention can be suitably used for a printed circuit board material or the like that requires a low dielectric constant.
The dielectric loss tangent of the polymer film is preferably 0.0001 to 0.003.

The absolute value of the linear expansion coefficient of the laminated film is preferably 30 ppm / ° C. or lower, more preferably 20 ppm / ° C. or lower, and even more preferably 10 ppm / ° C. or lower. In this case, the occurrence of warpage of the laminated film is effectively prevented regardless of the temperature of the atmosphere in which the laminated film is arranged. The lower limit of the absolute value of the linear expansion coefficient of the laminated film is 0 ppm / ° C.
The peel strength between the surface layer and the support layer in the laminated film is preferably 10 N / cm or more, more preferably 15 N / cm or more, still more preferably 20 N / cm or more. The upper limit of the peel strength of the laminated film is 100 N / cm.

In addition, the laminated film exhibits low water absorption (high water barrier property). It is considered that this factor is because the low water absorption of the F polymer complements the high water absorption of the base polymer because the surface layer and the support layer are not integrated with each other but exist independently of each other.
The water absorption rate of the laminated film is preferably 0.1% or less, more preferably 0.07% or less, still more preferably 0.05% or less. The lower limit of the water absorption rate of the laminated film is 0%.

The polymer film (single-layer film and laminated film) in the present invention has high ultraviolet (UV) absorption and is suitable for processing with a laser such as a UV-YAG laser. The reason for this is that the AR polymer is highly dispersed and uniformly distributed in the polymer film or surface layer while forming a certain matrix, so that the AR polymer has good UV absorption of the aromatic ring. It is considered that it is at the point of expression.
Since the polymer layer formed from the polymer film can easily form via holes having a good shape by laser processing, the laminated board having the polymer layer can be particularly preferably used as a printed circuit board material.

The polymer film in the present invention may be obtained by melt-kneading an F polymer and an AR polymer and extrusion molding. In this case, the laminated film is obtained by thermocompression bonding a film containing an F polymer and an AR polymer and a support layer.
The polymer film may be obtained by applying a powder dispersion liquid containing an F polymer powder, an AR polymer and a liquid dispersion medium to a substrate and heating the substrate. In this case, if the polymer film is peeled off from the base material, a single-layer polymer film is obtained, and if not peeled off, a laminated film having the base material as a support layer is obtained.

Examples of the metal substrate (metal layer of the laminated plate) in this method include metal foils such as copper, copper alloy, stainless steel, nickel, nickel alloy (including 42 alloy), aluminum, aluminum alloy, titanium, and titanium alloy. Be done.
As the metal foil, a copper foil is preferable, a rolled copper foil having no distinction between the front and back sides or an electrolytic copper foil having a distinction between the front and back sides is more preferable, and a rolled copper foil is further preferable. Since the rolled copper foil has a small surface roughness, transmission loss can be reduced even when the laminated board is processed into a printed circuit board. Further, the rolled copper foil is preferably used after being immersed in a hydrocarbon-based organic solvent to remove rolling oil.

The ten-point average roughness of the surface of the metal foil is preferably 0.01 to 4 μm. In this case, the adhesiveness to the polymer film is good, and it is easy to obtain a laminated board capable of producing a printed circuit board having excellent transmission characteristics.
The surface of the metal foil may be roughened. Examples of the roughening treatment method include a method of forming a roughening treatment layer, a dry etching method, and a wet etching method.
The thickness of the metal foil may be a thickness that can exhibit sufficient functions in the use of the laminated board. The thickness of the metal foil is preferably less than 20 μm, more preferably 2 to 15 μm.
Further, the surface of the metal foil may be partially or wholly treated with a silane coupling agent.

In this method, the polymer film and the metal substrate are thermocompression bonded at a temperature lower than the glass transition point of the AR polymer to obtain a laminated board.
The polymer film may have another layer on the surface opposite to the surface to be laminated with the metal substrate. Examples of the other layer include a substrate similar to the above-mentioned metal substrate and a prepreg (precursor of a fiber reinforced resin substrate).
The temperature at the time of thermocompression bonding is preferably 40 to 70 ° C. lower than the glass transition point of the AR polymer, and more preferably 45 to 65 ° C. lower. When thermocompression bonding is performed at such a temperature, the AR polymer is prevented from being softened more than necessary, the effect of preventing or suppressing the deformation of the polymer film is further enhanced, and a laminated body having excellent peel strength and flatness is obtained. Be done.
The specific temperature at the time of thermocompression bonding is preferably 250 to 300 ° C, more preferably 260 to 280 ° C. In this case, unnecessary softening of the AR polymer during thermocompression bonding can be prevented more reliably.

Thermocompression bonding is preferably performed at a vacuum degree of 20 kPa or less from the viewpoint of suppressing air bubble contamination and suppressing deterioration due to oxidation.
Further, at the time of thermocompression bonding, it is preferable to raise the temperature after reaching the above vacuum degree. If the temperature is raised before reaching the degree of vacuum, the polymer film may be crimped in a softened state, that is, in a state of having a certain degree of fluidity and adhesion, which may cause bubbles.
The pressure in thermocompression bonding is preferably 0.2 to 10 MPa from the viewpoint of firmly adhering the polymer film and the metal substrate while suppressing damage to the metal substrate.

In this method, it is preferable that the polymer film and the metal substrate are each long. In this case, the polymer film and the metal substrate are thermocompression bonded by roll-to-roll. Therefore, the polymer film and the metal substrate are thermocompression bonded in a state of being pulled in their longitudinal directions. Therefore, when the amount of deformation of the polymer film due to heating is large, elongated wrinkles along the longitudinal direction of the outer surface (the surface of the metal layer opposite to the polymer layer) of the obtained laminated board are likely to occur. That is, it tends to be in a wavy state along the lateral direction of the outer surface of the laminated board.

In this method, since the polymer film contains F polymer and AR polymer on its surface, the amount of deformation due to heating is small, and as a result, wrinkles are less likely to occur on the outer surface of the laminated board, and even if wrinkles occur, the degree of wrinkles occurs. (Number, height difference, etc.) becomes smaller.
Specifically, the maximum height waviness Wz of the outer surface of the laminated board is preferably 100 μm or less, and more preferably 50 μm or less. The lower limit of the maximum height swell Wz is 0 μm.
As described above, the laminated board having a small maximum height undulation Wz is easy to process into a printed circuit board, and it is easy to obtain a printed circuit board having excellent characteristics (low dielectric loss tangent, etc.).

In the laminated board, the peel strength between the metal substrate and the polymer film is preferably 10 N / cm or more, more preferably 15 N / cm or more, still more preferably 20 N / cm or more. The upper limit of the peel strength between the metal substrate and the polymer film is usually 100 N / cm. According to this method, deformation of the polymer film is suppressed during thermocompression bonding, so that the metal substrate and the polymer film are bonded with high adhesion, and a laminated board having high peel strength can be easily obtained.
The laminated board of the present invention (hereinafter, also referred to as “the main laminated board”) is a long polymer bonded to a long metal layer and a metal layer and containing an F polymer and an AR polymer on the surface on the metal layer side. Has a layer. The maximum height waviness Wz along the lateral direction of the outer surface of the laminated board (the surface opposite to the polymer layer of the metal layer) is 100 μm or less.

The definitions and scope of F polymers and AR polymers in this laminate are similar to those in this method, including preferred embodiments. Further, the range of the structure and physical properties (maximum height waviness Wz, peel strength between the metal layer and the polymer layer, etc.) in this laminated board is the same as those in this method, including suitable embodiments.
This laminated board can be used for manufacturing a printed circuit board as a flexible copper-clad laminated board or a rigid copper-clad laminated board.
For the printed circuit board, for example, a method of processing a metal layer in the main laminated board into a conductor circuit (pattern circuit) having a predetermined pattern by etching or the like, an electrolytic plating method (semi-additive method (SAP method)), or a modified semi of the main laminated body. It can be manufactured by using a method of processing into a pattern circuit by an additive method (MSAP method, etc.).
In the manufacture of a printed circuit board, an interlayer insulating film, a solder resist, or a coverlay film may be laminated on the pattern circuit after the pattern circuit is formed.

Although the method for manufacturing the laminated board and the laminated board of the present invention have been described above, the present invention is not limited to the configuration of the above-described embodiment.
For example, the laminated board of the present invention may be added to any other configuration or may be replaced with any configuration exhibiting the same function in the configuration of the above-described embodiment.
In addition, the method for manufacturing a laminated board of the present invention may be added to any other step in the configuration of the above-described embodiment, or may be replaced with any step that exhibits the same function.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.
1. 1. Preparation of each component [F polymer]
F polymer 1: PFA-based polymer containing 98.0 mol%, 0.1 mol%, and 1.9 mol% of TFE unit, NAH unit, and PPVE unit in this order (melting temperature: 300 ° C.).
F polymer 2: PFA polymer containing 97.5 mol% and 2.5 mol% of TFE units and PPVE units in this order (melting temperature: 305 ° C).
[powder]
Powder 1: Powder made of F polymer 1 having D50 of 1.9 μm Powder 2: Powder made of F polymer 2 having D50 of 2.0 μm

[AR polymer varnish]
Varnish 1: N-methyl-2-pyrrolidone solution containing AR polymer 1 (glass transition point: 315 ° C.), which is an aromatic polyimide (solid content: 10% by weight).
The AR polymer 1 includes 3,3'4,4'-benzophenone tetracarboxylic acid dianhydride, 2,4-diaminotoluene, and 3,3'4,4'-biphenyltetracarboxylic acid dianhydride. , 2,2-Bis {4- (4-aminophenoxy) phenyl} block copolymer with propane (molar ratio = 1: 1: 1: 1). In the following, N-methyl-2-pyrrolidone will be referred to as "NMP".
Varnish 2: NMP solution containing AR polymer 2 (glass transition point: 350 ° C.), which is an aromatic polyimide (solid content: 10% by weight)

[Dispersant]
Dispersant 1: CH ₂ = C (CH ₃ ) C (O) OCH ₂ CH ₂ (CF ₂ ) ₆ F and CH ₂ = C (CH ₃ ) C (O) (OCH ₂ CH ₂ ) ₂₃ OH copolymer A nonionic polymer having a fluorine content of 35% by mass [base film]
Polyimide film 1: Aromatic polyimide film with a thickness of 50 μm, a glass transition point of 315 ° C, an imide group density of 0.25, and a tensile elasticity of 0.3 GPa at 320 ° C. Polyimide film 2: Thickness of 50 μm, glass transition Aromatic polyimide film with a point of 340 ° C, an imide group density of 0.38, and a tensile elasticity of 5 GPa at 320 ° C [Metal substrate]
Electrolytic copper foil 1: "CF-T49A-DS-HD2" manufactured by Fukuda Metal Foil Powder Industry Co., Ltd. (thickness: 12 μm, Rzjis: 1.2 μm)

2. 2. Preparation of powder dispersion (powder dispersion 1)
First, 47 parts by mass of NMP, 3 parts by mass of dispersant 1 and 49.5 parts by mass of powder 1 were put into a pot, and then zirconia balls were put into the pot. Then, the pot was rolled under the condition of 150 rpm × 1 hour to disperse the powder 1 to obtain a mixed solution.
Next, the varnish of AR polymer 1 is stirred in this mixed solution at a rotation speed of 500 rpm so that the amount (solid content) of AR polymer 1 in the powder dispersion is 0.5% by mass. Addition was made to prepare a powder dispersion 1. That is, the amount of AR polymer 1 with respect to the total amount of F polymer 1 and AR polymer 1 is 1% by mass.
(Powder dispersion 2)
The powder dispersion liquid 2 was prepared in the same manner as the powder dispersion liquid 1 except that the powder 1 was changed to the powder 2.

3. 3. Preparation of polymer film (polymer film 1)
The powder dispersion 1 was applied to one surface of the polyimide film 1 by a small-diameter gravure reverse method and passed through a ventilation drying furnace (fired temperature: 150 ° C.) for 3 minutes to remove NMP and form a dry film. ..
Further, the powder dispersion liquid 1 was similarly applied to and dried on the other surface of the polyimide film 1 to form a dry film.
Next, the polyimide film 1 having the dry film formed on both sides was passed through a far-infrared ray furnace (furnace temperature: 320 ° C.) for 20 minutes to melt and fire the powder 1. As a result, a polymer layer (thickness: 25 μm) containing F polymer 1 and AR polymer 1 is formed on both sides of the support layer made of the polyimide film 1, and the polymer layer, the support layer, and the polymer layer are directly formed in this order. The polymer film 1 was obtained as a long laminated film.

(Polymer film 2)
A polymer layer (thickness) containing F polymer 2 and AR polymer 1 on both sides of the support layer made of the polyimide film 1 in the same manner as the polymer film 1 except that the powder dispersion 2 was used instead of the powder dispersion 1. : 25 μm) was formed, and the polymer film 2 was obtained as a long laminated film in which the polymer layer, the support layer, and the polymer layer were directly formed in this order.
(Polymer film 3)
Similar to the polymer film 1, the polymer layer containing the F polymer 1 and the AR polymer 2 on both sides of the support layer made of the polyimide film 1 except that the varnish of the AR polymer 2 is used instead of the varnish of the AR polymer 1 (similar to the polymer film 1). A polymer film 3 was obtained as a long laminated film in which the polymer layer, the support layer, and the polymer layer were directly formed in this order (thickness: 25 μm).
(Polymer film 4)
A polymer layer (thickness: 25 μm) containing F polymer 1 and AR polymer 1 on both sides of the support layer made of the polyimide film 2 in the same manner as the polymer film 1 except that the polyimide film 2 was used instead of the polyimide film 1. ) Was formed, and the polymer film 4 was obtained as a long laminated film in which the polymer layer, the support layer, and the polymer layer were directly formed in this order.

4. Manufacture of laminated boards (Example 1)
The electrolytic copper foil 1 was thermocompression bonded to both surfaces of the polymer film 1 by roll-to-roll to manufacture a laminated board 1. The conditions at the time of thermocompression bonding were a temperature of 270 ° C., a pressure of 1 MPa, and an atmosphere of 10 kPa.
(Example 2)
The laminated board 2 was manufactured in the same manner as in Example 1 except that the polymer film 1 was changed to the polymer film 2.

(Example 3)
The laminated board 3 was manufactured in the same manner as in Example 2 except that the temperature at the time of thermocompression bonding was 220 ° C.
(Example 4)
The laminated board 4 was manufactured in the same manner as in Example 2 except that the temperature at the time of thermocompression bonding was 340 ° C.
(Example 5)
The laminated board 5 was manufactured in the same manner as in Example 1 except that the polymer film 1 was changed to the polymer film 3.
(Example 6)
The laminated board 6 was manufactured in the same manner as in Example 1 except that the polymer film 1 was changed to the polymer film 4.

5. Evaluation 5-1. Occurrence of wrinkles The maximum height swell Wz along the lateral direction of each laminated board (the surface opposite to the polymer film of electrolytic copper foil 1) was measured according to JIS B 0601: 2013, and according to the following criteria. evaluated.
[Evaluation criteria]
〇: The maximum height swell Wz is 50 μm or less.
Δ: The maximum height swell Wz is more than 50 μm and 100 μm or less.
X: The maximum height swell Wz is more than 100 μm.

5-2. Peeling strength A rectangular test piece having a length of 100 mm and a width of 10 mm was cut out from each laminated plate. Then, the electrolytic copper foil 1 and the polymer film were peeled off from one end in the length direction of the test piece to a position of 50 mm. Next, using a tensile tester (manufactured by Orientec), peeling 90 degrees at a tensile speed of 50 mm / min with the position 50 mm from one end in the length direction of the test piece at the center, and applying the maximum load to the peel strength (N). / Cm) and evaluated according to the following evaluation criteria.
[Evaluation criteria]
〇: The peel strength is 15 N / cm or more.
Δ: The peel strength is 10 N / cm or more and less than 15 N / cm.
X: The peel strength is less than 10 N / cm.
The above results are shown in Table 1 below.

The laminated board of the present invention prevents or suppresses the occurrence of wrinkles. Therefore, the laminated board containing such a film can be processed into antenna parts, printed circuit boards, aircraft parts, automobile parts, and the like.

Claims (15)

A polymer film having a surface containing a tetrafluoroethylene-based polymer and a thermoplastic aromatic polymer and a metal substrate are arranged so that the surface is in contact with the metal substrate, and is lower than the glass transition point of the aromatic polymer. A method for manufacturing a laminated board, wherein the polymer film and the metal substrate are thermally pressure-bonded at a temperature to obtain a laminated board. The production method according to claim 1, wherein a laminated plate is obtained by thermocompression bonding the polymer film and the metal substrate at a temperature 40 to 70 ° C. lower than the glass transition point of the aromatic polymer. The production method according to claim 1 or 2, wherein the glass transition point of the aromatic polymer is 300 to 350 ° C. The production according to any one of claims 1 to 3, wherein the aromatic polymer is at least one selected from the group consisting of aromatic polyimide, aromatic polymaleimide, aromatic polyphenylene ether, and aromatic styrene elastomer. Method. The manufacturing method according to any one of claims 1 to 4, wherein the temperature at the time of thermocompression bonding is 250 to 300 ° C. The polymer film comprises a surface layer having the surface and a support layer supporting the surface layer and containing a base polymer, and the difference between the glass transition point of the aromatic polymer and the glass transition point of the base polymer. The production method according to any one of claims 1 to 5, wherein the absolute value of is 20 ° C. or lower. The production method according to claim 6, wherein the glass transition point of the base polymer is 230 to 340 ° C. The production method according to claim 6 or 7, wherein the base polymer is an aromatic polyimide. The production method according to any one of claims 1 to 8, wherein the tetrafluoroethylene polymer is a tetrafluoroethylene polymer having a melting temperature of 260 to 320 ° C. The tetrafluoroethylene-based polymer is a tetrafluoroethylene-based polymer containing units based on perfluoro (alkyl vinyl ether) and containing 1.5 to 5.0 mol% of units based on perfluoro (alkyl vinyl ether) with respect to all units. , The manufacturing method according to any one of claims 1 to 9. The manufacturing method according to any one of claims 1 to 10, wherein the polymer film and the metal substrate are each long. The manufacturing method according to claim 11, wherein in the laminated board, the maximum height waviness Wz along the lateral direction of the surface of the metal substrate opposite to the polymer film is 100 μm or less. The manufacturing method according to any one of claims 1 to 12, wherein in the laminated board, the peel strength between the metal substrate and the polymer film is 10 N / cm or more. The metal layer has a long metal layer and a long polymer layer bonded to the metal layer and containing a tetrafluoroethylene-based polymer and a thermoplastic aromatic polymer on the surface on the metal layer side. A laminated board having a maximum height waviness Wz of 100 μm or less along the lateral direction of the surface opposite to the polymer layer. The laminated board according to claim 14, wherein the peel strength between the metal layer and the polymer layer is 10 N / cm or more.