TWI850322B - Laminated body and method for producing the same, method for producing a composite laminate, and method for producing a polymer film - Google Patents

Abstract

The present invention provides a laminate having uniform and high adhesion between a polymer layer and a metal foil layer, and a method for manufacturing the same. The laminate comprises a metal foil layer and a polymer layer directly disposed on the surface of the metal foil layer and comprising a tetrafluoroethylene polymer having a melt viscosity of 1×10 ² to 1×10 ⁶ Pa·s at 380°C, wherein the metal foil layer has no silicon atoms on the surface, or has a nickel atom ratio of 0.03 to 0.25 mass % as detected by fluorescent X-ray analysis of the surface.

Description

Laminated body and method for producing the same, method for producing a composite laminate, and method for producing a polymer film

The present invention relates to a laminate having a specific polymer layer disposed in direct contact with a surface of a specific metal foil layer, a method for manufacturing the laminate, a method for manufacturing a composite laminate, and a method for manufacturing a polymer film.

In order to reduce the dielectric constant in printed wiring boards, the surface roughness of the copper foil is reduced and a polymer layer using a low dielectric constant polymer is formed. However, the polarity of low dielectric constant polymers is generally low and lacks adhesion to other materials. In addition, the copper foil with reduced surface roughness has too high surface smoothness, so it is difficult to produce the anchoring effect of the polymer layer, resulting in poor adhesion. Therefore, it is difficult to firmly bond the polymer layer containing the low dielectric constant polymer to the low-roughness copper foil.

In order to improve the adhesion between the copper foil and the polymer layer, the surface of the copper foil is treated with a surface treatment agent containing silicon atoms such as a silane coupling agent. It is no exaggeration to say that the surface of the copper foil used in commercially available printed wiring boards is treated with a silane coupling agent. In recent years, tetrafluoroethylene polymers (TFE polymers) have received attention as low dielectric constant polymers, and TFE polymers are particularly lacking in adhesion to other materials. Therefore, the surface of the copper foil is still treated with a silane coupling agent to improve adhesion to the copper foil (see Patent Document 1).

In addition, in printed wiring boards, there are also printed wiring boards in which the spacing between wirings has been promoted to 30 μm or less. If the spacing is such, copper ions are easily eluted from the copper foil, resulting in a phenomenon (migration) of short circuit between wirings. Therefore, in order to prevent the elution of copper ions caused by copper oxidation, there is a situation in which a metal layer such as nickel, cobalt, zinc, etc. is provided between the copper foil and the polymer layer (insulating layer) as a barrier layer (see patent documents 2 and 3).

Nickel is excellent as a barrier layer, but on the other hand, since its resistivity is higher than that of copper, the transmission loss of a printed wiring board containing a large amount of nickel becomes larger. In addition, since nickel itself is easily modified at high temperatures, the adhesion between the polymer layer and the copper foil is easily reduced after exposure to high temperatures during the manufacturing process of the printed wiring board. To solve this problem, it is proposed to set an anti-oxidation treatment layer containing cobalt and molybdenum on the surface of the copper foil (see patent document 4).

Furthermore, when manufacturing a printed wiring board, there is a situation where after the copper foil with a TFE-based polymer layer is processed into a circuit pattern, a prepreg is bonded to the TFE-based polymer layer and stacked to cover the entire circuit pattern. In this case, the bonding strength between the TFE-based polymer layer and the prepreg is low, and interlayer peeling is easily generated between them. Therefore, before bonding the prepreg, the surface of the TFE-based polymer layer is subjected to surface treatment (silane coupling agent treatment, plasma treatment, etc.) to improve the bonding property (see patent documents 5 and 6). [Prior art document] [Patent document]

[Patent Document 1] International Publication No. 2014/192718 [Patent Document 2] Japanese Patent Publication No. 2008-118163 [Patent Document 3] Japanese Patent Publication No. 2008-132757 [Patent Document 4] Japanese Patent Publication No. 2017-141489 [Patent Document 5] Japanese Patent Publication No. 2018-011033 [Patent Document 6] International Publication No. 2018/212285

[The problem the invention is trying to solve]

However, according to the research of the inventors, TFE polymers also lack interaction with silane coupling agents, so the effect of improving the adhesion between TFE polymers and copper foil obtained by silane coupling agents is limited. In addition, silane coupling agents are prone to deviations in their reactivity or deviations in the amount of adhesion on the surface of copper foil, which become unstable factors in the adhesion of TFE polymers to copper foil. The inventors have come to the following conclusion: if specific TFE polymers and metal foils are used, the unstable factors caused by silane coupling agents can be eliminated.

Furthermore, according to the research of the inventors, when TFE polymers are used as low dielectric constant polymers, the initial adhesion between the layer containing cobalt or molybdenum and the TFE polymer is significantly lower, and the adhesion after high temperature exposure is still insufficient. Therefore, the inventors have made great efforts to improve the initial adhesion, and the following conclusions have been drawn: if a metal foil having a surface with nickel in a specific trace range is used, and a polymer layer containing a specific TFE polymer is provided on the surface of the metal foil, a laminate having excellent initial adhesion and adhesion after high temperature exposure and excellent electrical properties can be obtained.

Furthermore, the inventors of the present invention have come to the conclusion that by using a metal foil having specific surface properties, a polymer layer containing a TFE-based polymer that exhibits high adhesion to a prepreg can be obtained, thereby completing the present invention.

That is, the object of the present invention is to provide a laminate that can obtain uniform and high adhesion between a polymer layer and a metal foil layer, and a method for manufacturing the same. In addition, the object of the present invention is to provide a laminate that has excellent electrical properties, has high initial adhesion between a polymer layer and a metal foil layer, and can maintain high adhesion even after a high temperature thermal history, and a method for manufacturing the same. Furthermore, the object of the present invention is to provide a method for manufacturing a polymer film that can exhibit high adhesion to a prepreg or the like even if surface treatment is omitted, and a method for manufacturing a composite laminate that is not prone to peeling between a polymer layer and a prepreg layer. [Technical means for solving the problem]

The present invention has the following aspects. <1> A laminate having a metal foil layer and a polymer layer, wherein the polymer layer is directly disposed on the surface of the metal foil layer and comprises a tetrafluoroethylene polymer having a melt viscosity of 1×10 ² to 1×10 ⁶ Pa·s at 380°C; the metal foil layer is a metal foil layer having no silicon atoms on the surface, or a metal foil layer having a nickel atom ratio of 0.03 to 0.25 mass % when the surface is analyzed by fluorescent X-ray. <2> The laminate as described in <1> above, wherein the metal foil layer has a substrate layer and a roughening layer comprising metal particles and having the surface. <3> A laminate as described in <1> or <2> above, wherein the metal foil layer comprises a substrate layer and a roughened layer containing metal particles and having the surface, and the metal particles are formed of copper, nickel, phosphorus, tungsten, arsenic, molybdenum, chromium, cobalt, zinc, or an alloy containing one or more of these. <4> A laminate as described in any one of <1> to <3> above, wherein the metal foil layer comprises a substrate layer and a roughened layer containing metal particles and having the surface, and the metal particles include needle-shaped metal particles. <5> A laminate as described in any one of <1> to <4> above, wherein the ten-point average roughness of the surface of the metal foil layer is not less than 0.1 μm. <6> The laminate as described in any one of <1> to <5> above, wherein the tetrafluoroethylene polymer is a tetrafluoroethylene polymer containing units based on perfluoro(alkyl vinyl ether) or polytetrafluoroethylene having a number average molecular weight of 200,000 or less. <7> The laminate as described in any one of <1> to <6> above, wherein the tetrafluoroethylene polymer is a tetrafluoroethylene polymer containing units based on perfluoro(alkyl vinyl ether) and having an oxygen-containing polar group or a tetrafluoroethylene polymer containing 2.0 to 5.0 mol% of units based on perfluoro(alkyl vinyl ether) relative to all units and having no oxygen-containing polar group. <8> The laminate as described in any one of <1> to <7> above, wherein the peel strength of the polymer layer with respect to the metal foil layer is 10 N/cm or more. <9> A method for producing a laminate, comprising forming a polymer layer comprising a tetrafluoroethylene polymer having a melt viscosity of 1×10 ² to 1×10 ⁶ Pa·s at 380°C in direct contact with the surface of the metal foil without treating the surface of the metal foil with a silane coupling agent, thereby obtaining a laminate having the polymer layer disposed in direct contact with the surface of the metal foil layer comprising the metal foil. <10> A method for producing a laminate, comprising forming a polymer layer comprising a tetrafluoroethylene polymer having a melt viscosity of 1×10 ² to 1×10 ⁶ Pa·s at 380°C in direct contact with the surface of a metal foil having a nickel atom ratio of 0.03 to 0.25 mass % as detected by fluorescent X-ray analysis, thereby obtaining a laminate having the polymer layer disposed in direct contact with the surface of a metal foil layer comprising the metal foil. <11> A method for producing a composite laminate, comprising removing at least a portion of the metal foil layer of a laminate having a surface having a ten-point average roughness of 0.1 μm or more and a polymer layer provided on the surface and comprising a tetrafluoroethylene polymer having a melt viscosity of 1×10 ² to 1×10 ⁶ Pa·s at 380°C, and contacting the exposed polymer layer with a prepreg to obtain a composite laminate having at least the polymer layer and the prepreg layer. <12> The method of <11>, wherein the exposed surface of the polymer layer is contacted with the prepreg without subjecting the surface of the polymer layer to hydrophilization. <13> A method for manufacturing a composite laminate, comprising removing at least a portion of the metal foil layer of a laminate having a surface with a ten-point average roughness of 0.1 μm or more and a polymer layer disposed on the surface and comprising a tetrafluoroethylene polymer having a melt viscosity of 1×10 ² to 1×10 ⁶ Pa·s at 380°C, applying a solder resist on the exposed polymer layer and hardening the solder resist to form a solder resist layer, thereby obtaining a composite laminate having at least the polymer layer and the solder resist layer laminated thereon. <14> A manufacturing method as described in <13> above, wherein the surface of the exposed polymer layer is treated with an acid solution, and a solder resist is directly applied in this state to harden the solder resist to form a solder resist layer. <15> A method for manufacturing a polymer film, wherein the metal foil layer having a surface with a ten-point average roughness of 0.1 μm or more and a polymer layer disposed on the surface and comprising a tetrafluoroethylene polymer having a melt viscosity of 1×10 ² to 1×10 ⁶ Pa·s at 380°C are removed from the metal foil layer, and the remaining polymer layer is used as a polymer film. [Effect of the Invention]

According to the present invention, a laminate having uniform and high adhesion between a polymer layer and a metal foil and a method for manufacturing the same can be provided. In addition, according to the present invention, a laminate having high initial adhesion between a polymer layer and a metal foil and excellent electrical properties that can maintain high adhesion even after a high temperature thermal history and a method for manufacturing the same can be provided. Furthermore, according to the present invention, a polymer film having high adhesion to a prepreg and the like and a composite laminate having low peeling between a polymer layer and a prepreg layer can be provided.

The following terms have the following meanings. "D50 of powder" is the particle size distribution of powder measured by laser diffraction-scattering method, with the total volume of the cluster of particles constituting the powder (hereinafter, also referred to as "powder particles") set as 100%, and the particle size at the point on the cumulative curve where the cumulative volume becomes 50% (volume-based cumulative 50% diameter). "D90 of powder" is the particle size distribution of powder measured by laser diffraction-scattering method, with the total volume of the cluster of powder particles set as 100%, and the particle size at the point on the cumulative curve where the cumulative volume becomes 90% (volume-based cumulative 90% diameter). That is, the D50 and D90 of the powder are the volume-based cumulative 50% diameter and volume-based cumulative 90% diameter of the powder particles, respectively. "Polymer melt viscosity" is measured in accordance with ASTM D 1238 using a rheometer and a 2ϕ-8L mold, with a polymer sample (2 g) preheated at a measured temperature for 5 minutes held at a load of 0.7 MPa at the measured temperature. "Polymer melting temperature (melting point)" is the temperature corresponding to the maximum value of the melting peak of the polymer measured by differential scanning calorimetry (DSC). "Viscosity" is a value measured using a B-type viscometer at room temperature (25°C) and a rotation speed of 30 rpm. Repeat the measurement 3 times and set it as the average of the 3 measurement values. "Ten-point average roughness (Rzjis)" is the value specified in Annex JA of JIS B 0601:2013. "Peel strength" is the maximum load (N/cm) applied when a laminate cut into a rectangular shape (length 100 mm, width 10 mm) is fixed at a position 50 mm from one end in the length direction and the laminate is pulled at 90° from one end in the length direction at a tension speed of 50 mm/min. The "unit" of a polymer can be an atomic group directly formed from a monomer by a polymerization reaction, or an atomic group obtained by treating a polymer obtained by a polymerization reaction using a specific method to transform a part of the structure. The unit based on monomer A contained in the polymer is also referred to as "monomer A unit".

The laminate of the present invention (the present laminate) comprises a metal foil layer and a polymer layer (hereinafter also referred to as "F layer") provided in direct contact with the surface of the metal foil layer and comprising a tetrafluoroethylene polymer (hereinafter also referred to as "F polymer") having a melt viscosity of 1×10 ² to 1×10 ⁶ Pa·s at 380°C. The metal foil layer of the present laminate is a metal foil layer having no silicon atoms on the surface (hereinafter also referred to as "metal foil layer 1"), or a metal foil layer having a nickel atom ratio of 0.03 to 0.25 mass % detected when the surface is subjected to fluorescent X-ray analysis (hereinafter also referred to as "metal foil layer 2"). Hereinafter, the present integrated multilayer body having the metal foil layer 1 is also referred to as the present integrated multilayer body 1, and the present integrated multilayer body having the metal foil layer 2 is also referred to as the present integrated multilayer body 2.

The present laminate 1 has a metal foil layer 1 and an F layer provided in direct contact with the surface of the metal foil layer 1. Furthermore, the F layer may be provided on only one surface of the metal foil layer 1 or on both surfaces. In the present laminate 1, there are no silicon atoms on the surface of the metal foil layer 1 (the surface on the F layer side). This means that the surface of the metal foil layer 1 has not been treated with a silane coupling agent. That is, the manufacturing method of the present laminate 1 is a method of forming the F layer in direct contact with the surface without treating the surface of the metal foil layer 1 with a silane coupling agent. Furthermore, whether silicon atoms exist on the surface of the metal foil layer 1 can be confirmed by analyzing the surface of the metal foil layer 1 using the X-ray fluorescence analysis (XRF) method. According to the analysis, it is sufficient as long as the detection amount of silicon atoms is below the detection limit.

Regarding the metal foil constituting the metal foil layer 1, it is believed that oxides (hydroxides, etc.) generated by oxidation exist on its surface. On the other hand, it is believed that the F polymer having a specific melt viscosity easily interacts with the oxides and/or metal atoms existing on the surface of the metal foil, and in particular, if the F polymer contains an oxygen-containing polar group, the oxygen-containing polar group interacts more strongly with the oxides and/or metal atoms existing on the surface of the metal foil. It can be inferred that as a result, in the present laminate 1, the F layer containing the F polymer exhibits higher adhesion to the metal foil. Furthermore, the treatment with the silane coupling agent is performed by utilizing the wetting diffusion of a solution containing the silane coupling agent on the surface of the metal foil. Therefore, it can be considered that: in the initial stage, the solution tends to gather at the part bound by the silane coupling agent, and the part bound by the silane coupling agent and the part not bound by the silane coupling agent are dispersed in an island shape, and the amount of the silane coupling agent existing on the surface of the metal foil is deviated. In addition, the degree is greatly affected by the surface properties of the metal foil. Therefore, if the F layer is formed on the surface of the metal foil in this state, it is difficult to show uniform adhesion between the F layer and the metal foil. In contrast, since the present multilayer body 1 does not use a silane coupling agent to treat the surface of the metal foil, it can prevent the above-mentioned adverse conditions from occurring, and it can be inferred that uniform adhesion can be obtained between the F layer and the metal foil (metal foil layer 1).

The present laminate 2 has a metal foil layer 2 and an F layer provided in direct contact with the surface of the metal foil layer 2. Furthermore, the F layer may be provided on only one surface of the metal foil layer 2 or on both surfaces. In the present laminate 2, a specific amount (trace amount) of nickel atoms exists on the surface of the metal foil layer 2 (the surface on the F layer side). The manufacturing method of the present laminate 2 is a method of forming the F layer in direct contact with the surface of the metal foil in which nickel atoms exist in a specific amount. Furthermore, the ratio of nickel atoms existing on the surface of the metal foil can be measured by analyzing the surface of the metal foil by fluorescent X-ray analysis (XRF).

Regarding the metal foil constituting the metal foil layer 2, it is believed that there is a nickel oxide (hydroxide, etc.) generated by oxidation on its surface. On the other hand, it is believed that the F polymer having a specific melt viscosity tends to interact more strongly with the oxide or nickel atoms existing on the surface of the metal foil, and in particular, if the F polymer contains an oxygen-containing polar group, the oxygen-containing polar group interacts more strongly with the oxide or nickel atoms. It can be inferred that as a result, in the present laminate 2, the F layer containing the F polymer shows a higher initial adhesion with the metal foil (metal foil layer 2). In addition, it is believed that the presence of nickel atoms can play an effect of preventing the deterioration (corrosion) of the surface of the metal foil caused by the F polymer. Therefore, it can be inferred that after the laminate 2 has undergone a thermal history at high temperature, a relatively high bonding force can be maintained between the F layer and the metal foil (metal foil layer 2).

The F polymer of the present invention is a polymer containing a unit (TFE unit) based on tetrafluoroethylene (TFE), and is preferably a hot melt processable polymer. The melt viscosity of the F polymer at 380°C is 1×10 ² to 1×10 ⁶ Pa·s, preferably 1×10 ³ to 1×10 ⁶ Pa·s. The melting temperature of the F polymer is preferably 140 to 320°C, more preferably 200 to 320°C, and further preferably 260 to 320°C. In this case, it is easy to further improve the adhesion of the F layer to the metal foil (metal foil layers 1 and 2).

The F polymer preferably has an oxygen-containing polar group. The oxygen-containing polar group possessed by the F polymer may be contained in a unit based on a monomer having an oxygen-containing polar group, may be contained in the terminal part of the polymer main chain, or may be contained in the polymer by surface treatment (radiation treatment, electron beam treatment, corona treatment, plasma treatment, etc.), and the former is preferred. In addition, the oxygen-containing polar group possessed by the F polymer may also be a group prepared by modifying a polymer having a group that can form an oxygen-containing polar group. The oxygen-containing polar group contained in the terminal group of the polymer can be obtained by adjusting the components (polymerization initiator, chain transfer agent, etc.) used in the polymerization of the polymer. The oxygen-containing polar group is a polar atomic group containing an oxygen atom. However, the oxygen-containing polar group in the present invention does not include an ester bond itself and an ether bond itself, but includes an atomic group containing these bonds as a characteristic group.

The oxygen-containing polar group is preferably at least one group selected from the group consisting of a hydroxyl-containing group, a carbonyl-containing group, an acetal group and an oxoalkyl group, more preferably a _hydroxyl -containing group or a carbonyl-containing group, further preferably _-CF2CH2OH , -C( _CF3 ) _2OH , 1,2-diol group (-CH(OH) _CH2OH ), _-CF2C (O)OH, >CFC(O)OH, formamide group (-C(O) _NH2 , etc.), acid anhydride residue (-C(O)OC(O)-), imide residue (-C(O)NHC(O)-, etc.), dicarboxylic acid residue (-CH(C(O)OH) _CH2C (O)OH, etc.) or carbonate group (-OC(O)O-). Furthermore, from the viewpoint of not easily damaging the adhesion of the F layer to the metal foil, the oxygen-containing polar group is preferably a polar group that is a cyclic group or a ring-opened group of a cyclic acid anhydride residue, a cyclic amide residue, a cyclic carbonate group, a cyclic acetal group, a 1,2-dicarboxylic acid residue or a 1,2-diol group, and the most preferred is a cyclic acid anhydride residue. The cyclooxyalkylene group is preferably an epoxide group or an oxacyclobutyl group.

The F polymer is preferably a polymer comprising a TFE unit, a unit based on hexafluoropropylene (HFP), perfluoro(alkyl vinyl ether) (PAVE) or fluoroalkylethylene (FAE) (hereinafter, also referred to as a "PAE unit"), and a unit based on a monomer having an oxygen-containing polar group (hereinafter, also referred to as a "polar unit"). The ratio of the TFE unit is preferably 50 to 99 mol% in all the units constituting the F polymer, and is particularly preferably 90 to 99 mol%. The PAE unit is preferably a unit based on PAVE or a unit based on HFP, and is particularly preferably a unit based on PAVE. The PAE unit may also be two or more.

Examples of PAVE include _CF2 = _CFOCF3 (PMVE ₎ , _{CF2 = CFOCF2CF3} , CF2 ₌ CFOCF2CF2CF3 ( _PPVE ), _CF2 = _{CFOCF2CF2CF2CF3} , and _CF2 =CFO( _CF2 ) _8F , and PMVE or PPVE is preferred. Examples of FAE include _CH2 =CH( _CF2 ) _{2F ( PFEE} ), CH2=CH( _CF2 ) _3F , _CH2 =CH( _CF2 ) _4F ( _PFBE ), _CH2 =CF( _CF2 ) _3H , and _CH2 =CF( _CF2 ) _4H , _{and PFEE} or PFBE is preferred. The ratio of the PAE unit is preferably 0.5 to 9.97 mol % in all the units constituting the F polymer, more preferably 0.5 to 9.97 mol %.

The polar unit is preferably a unit based on a monomer having an anhydride residue, a carbonate group, a cyclic acetal group, a 1,2-dicarboxylic acid residue, a 1,2-diol residue, or a 1,3-diol residue, more preferably a monomer unit having a cyclic anhydride residue or a cyclic carbonate group, and more preferably a monomer unit having a cyclic anhydride residue. The polar unit may be one type or two or more types. The monomer having a cyclic anhydride residue is preferably itaconic anhydride, conic anhydride, 5-norbutene-2,3-dicarboxylic anhydride (also known as bicycloheptene dicarboxylic anhydride; hereinafter, also referred to as "NAH") or maleic anhydride, more preferably NAH. The ratio of the polar unit is preferably 0.01 to 3 mol % in all the units constituting the F polymer.

In this case, the F polymer may further include units other than TFE units, PAE units and polar units (hereinafter also referred to as "other units"). The other units may be one or more. As monomers forming other units, ethylene, propylene, vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride (VDF), and chlorotrifluoroethylene (CTFE) can be listed. The other units are preferably ethylene, VDF or CTFE, and more preferably ethylene. The ratio of other units in the F polymer is preferably 0 to 50 mol%, more preferably 0 to 40 mol%, in all units constituting the F polymer.

As a preferred embodiment of the F polymer, there can be cited an F polymer comprising a PAVE-based unit (PAVE unit) or a PTFE having a number average molecular weight of 200,000 or less. Furthermore, the number average molecular weight of the above-mentioned PTFE is a value calculated based on the following formula (1). Mn = 2.1 × 10 ¹⁰ × ΔHc ^-5.16 (1) In formula (1), Mn represents the number average molecular weight of the above-mentioned PTFE, and ΔHc represents the crystallization heat (cal/g) of the above-mentioned PTFE measured by differential scanning calorimetry. The Mn of the above-mentioned PTFE is preferably 10 or less, and more preferably 50,000 or less. The Mn of the above-mentioned PTFE is preferably 10,000 or less.

As a more preferable aspect of the F polymer, there can be listed: an F polymer containing PAVE-based units and having oxygen-containing polar groups, or an F polymer containing 2.0 to 5.0 mol% of PAVE-based units relative to all units but not having oxygen-containing polar groups. The F polymer in this aspect is easy to form microspherulites in the F layer, and the adhesion with other components is easy to increase.

The former polymer preferably contains 90-99 mol% of TFE units, 0.5-9.97 mol% of PAVE units and 0.01-3 mol% of polar units relative to all units. The content of PAVE units in the latter polymer is preferably 2.1 mol% or more relative to all units, and more preferably 2.2 mol% or more. The latter polymer preferably contains only TFE units and PAVE units, and contains 95.0-98.0 mol% of TFE units and 2.0-5.0 mol% of PAVE units relative to all units.

Furthermore, the latter polymer does not have an oxygen-containing polar group, which means that the polymer has less than 500 oxygen-containing polar groups for every 1×10 ⁶ carbon atoms constituting the main chain of the polymer. The above number of oxygen-containing polar groups is preferably 100 or less, and more preferably 50 or less. The lower limit of the above number of oxygen-containing polar groups is usually 0. The latter polymer can be produced using a polymerization initiator or a chain transfer agent that does not generate an oxygen-containing polar group as an end group of the polymer chain, or can be produced by fluorinating an F polymer having an oxygen-containing polar group (an F polymer having an oxygen-containing polar group derived from a polymerization initiator at the end group of the main chain of the polymer). As a method of fluorination treatment, a method using fluorine gas can be cited (see Japanese Patent Laid-Open No. 2019-194314, etc.).

Examples of the metal foil constituting the metal foil layers 1 and 2 include copper, iron, nickel, aluminum, zinc, and alloys thereof (copper alloy, stainless steel, nickel alloy (including 42 alloy), aluminum alloy, etc.). As the metal foil, copper foil is preferred, and copper foils such as rolled copper foil with no difference between the front and back sides, electrolytic copper foil with difference between the front and back sides, and rolled copper foil is more preferred. Rolled copper foil has a smaller surface roughness, so even when the laminate is processed into a printed wiring board, transmission loss can be reduced. In addition, the rolled copper foil is preferably used after being immersed in a hydrocarbon organic solvent to remove the rolling oil. The surface forming the F layer may be any surface in the rolled copper foil, and may be any surface of the precipitation surface or the glossy surface in the electrolytic copper foil. Furthermore, the metal foil may be a metal foil attached to a carrier formed by laminating the metal foil on the carrier via an intermediate layer.

Furthermore, the metal foil may also be a laminated structure having a base layer (e.g., copper foil) containing the above-mentioned metal and a roughening layer containing metal particles (roughening particles). In this case, the surface of the roughening layer constitutes the surface of the metal foil. As the above-mentioned roughening layer, a roughening layer containing metal particles (roughening particles) containing nickel can be cited. The metal particles are preferably formed of copper, nickel, phosphorus, tungsten, arsenic, molybdenum, chromium, cobalt, zinc, or an alloy containing one or more of these, and more preferably formed of copper, nickel, cobalt, or an alloy containing one or more of these. The metal particles are preferably formed of nickel alone, or an alloy of nickel and at least one of copper, phosphorus, tungsten, arsenic, molybdenum, chromium, cobalt and zinc, and most preferably an alloy containing nickel and at least one of copper and cobalt. The metal particles have excellent adhesion to the metal (especially copper) constituting the substrate layer.

In addition, when the laminate is processed into a printed wiring board, even if narrow and short-distance wiring (e.g., less than 30 μm) is formed from the metal foil (metal foil layers 1 and 2), migration between the wirings can be better prevented. Furthermore, the metal particles containing nickel are easily precipitated onto the base layer in the form of needle-shaped metal particles. If the roughening layer contains needle-shaped metal particles, the anchoring effect of the F layer on the metal foil surface is further improved, and the adhesion of the F layer to the metal foil can be fully improved.

The ratio of nickel atoms present on the surface of the metal foil (metal foil layer 2) is 0.03-0.25 mass%, preferably 0.04-0.2 mass%, and more preferably 0.05-0.15 mass%. If nickel atoms are present within the above range, the effect of preventing the surface degradation (corrosion) of the metal foil by the F polymer can be more effectively exerted, and even when the nickel atoms are modified, the influence is small. Therefore, it is not easy to produce a decrease in the adhesion of the F layer to the surface of the metal foil (metal foil layer 2). In addition, since the ratio of nickel atoms with a higher resistivity will not be too much, even when the laminate is processed into a printed wiring board, the reduction of transmission loss can be prevented.

Furthermore, in the metal foil formed by the layer, the roughened layer can form unevenness reflecting the shape of the metal particles. Therefore, the anchoring effect of the F layer on the surface of the metal foil (metal foil layers 1 and 2) can be better exerted, and as a result, the adhesion (close adhesion) of the F layer to the metal foil (metal foil layers 1 and 2) is improved. In this case, the average particle size of the metal particles is preferably 0.1 to 0.25 μm. From the perspective of further improving the adhesion of the F layer to the metal foil (metal foil layers 1 and 2), the ten-point average roughness of the surface of the metal foil (the surface on the F layer side) is preferably 0.1 to 1.5 μm, and more preferably 0.3 to 1.3 μm. Furthermore, since the surface roughness of the metal foil will not be too large if the ten-point average roughness is within the above range, the increase in transmission loss can be suppressed even when the multilayer body is processed into a printed wiring board.

The ten-point average roughness of the surface of the roughening layer can be adjusted by setting the size of the metal particles, the number of metal particles, etc. The roughening layer is preferably formed by electroplating with the substrate layer as the cathode to precipitate (electrodeposit) the metal particles onto the substrate layer. In this case, the electroplating amount such as the size of the metal particles and the number of metal particles can be mainly controlled by adjusting the current density and the electroplating time. During electroplating, the plating conditions (1) or (2) shown below can be preferably used.

<Plating conditions (1)> Liquid composition: copper salt 10-20 g/L, nickel salt 7-10 g/L, cobalt salt 7-10 g/L Liquid temperature: 30-60℃ Current density: 1-50 A/ ^dm2 pH value: 2.0-3.0 Electrodeposition time: 0.12-1.15 seconds Furthermore, the electrodeposition amount of each metal per 1 ^dm2 is preferably 15-40 mg for copper, 100-1500 μg for nickel, and 700-2500 μg for cobalt.

<Coating conditions (2)> ・Primary particle coating (1) Liquid composition: copper salt 10-15 g/L, nickel salt 0-10 g/L, cobalt salt 0-20 g/L, sulfuric acid 10-60 g/L Liquid temperature: 20-40°C Current density: 10-50 A/ ^dm2 Electrodeposition time: 0.2-5 seconds ・Primary particle coating (2) Liquid composition: copper salt 10-30 g/L, sulfuric acid 70-120 g/L Liquid temperature: 30-50°C Current density: 3-30 A/ ^dm2 Electrodeposition time: 0.2-5 seconds ・Secondary particle coating Liquid composition: copper salt 10-20 g/L, nickel salt 0-15 g/L, cobalt salt 0～10 g/L Liquid temperature: 30～40℃ Current density: 10～35 A/ ^dm2 Electrodeposition time: 0.2～5 seconds

Furthermore, the surface of the metal foil can be subjected to a roughening treatment such as dry etching or wet etching to adjust the ten-point average roughness of the surface to the above range. In addition, by combining the F polymer with the metal constituting the metal foil, even if the above roughening treatment is omitted, a higher adhesion between the F layer and the metal foil (metal foil layers 1 and 2) can be obtained. Furthermore, from the perspective of improving various properties, the metal foil can have at least one layer of a heat-resistant treatment layer, a rust-proof treatment layer, and a chromate treatment layer. In the case where the metal foil is a laminated structure, these layers can be arranged on the surface of the roughening treatment layer on the opposite side of the base layer, or between the roughening treatment layer and the metal foil. Furthermore, the formation of the heat-resistant treatment layer, the rust-proof treatment layer or the chromate treatment layer can adopt a known method. In addition, when the heat-resistant treatment layer, the rust-proof treatment layer or the chromate treatment layer constitutes the outermost layer of the metal foil, its surface constitutes the surface of the metal foil. The thickness of the metal foil can be appropriately determined depending on the purpose of the laminate. When the laminate is processed into a printed wiring board for use, it is preferably 1 to 100 μm, and more preferably 6 to 30 μm. In addition, when using a laminated metal foil formed by laminating an ultra-thin metal foil and a supporting metal foil, the thickness of the ultra-thin metal foil is preferably 2 to 5 μm.

The method for manufacturing the laminated body is to form an F layer in direct contact with the surface of the metal foil without treating the surface of the metal foil with a silane coupling agent, thereby manufacturing the laminated body 1 having the F layer directly disposed on the surface of the metal foil layer 1 containing the metal foil, or to form an F layer in direct contact with the surface of the metal foil containing a specific amount of nickel atoms, thereby manufacturing the laminated body 2 having the F layer directly disposed on the surface of the metal foil layer 2 containing the metal foil. The method for manufacturing the laminated body is preferably to roughen the surface of the metal foil in the manner described above before forming the F layer on the surface of the metal foil as needed. The F layer is preferably formed by applying a dispersion prepared by dispersing F polymer powder in a solvent to the surface of the metal foil and heating the dispersion, or by hot-pressing a film containing the F polymer to the surface of the metal foil.

In the method of applying a dispersion liquid to the surface of a metal foil and heating the metal foil, if the dispersion liquid is applied to the surface of the metal foil and the metal foil applied with the dispersion liquid is heated, the solvent can be removed from the dispersion liquid, and the present laminated bodies 1 and 2 formed with the F layer can be obtained by baking the powder. As a method of applying a dispersion liquid to the surface of a metal foil, any method can be used as long as it can form a stable liquid coating (wet film) containing the dispersion liquid on the surface of the metal foil. Examples of the method include coating method, liquid droplet discharge method, and immersion method, and coating method is preferred. If the coating method is used, a liquid coating can be efficiently formed on the surface of the metal foil using simple equipment. As coating methods, there can be listed: spray coating, roller coating, rotary coating, gravure coating, micro-gravure coating, gravure offset coating, blade coating, contact coating, rod coating, die nozzle coating, fountain Mayer bar coating, and slot die nozzle coating.

When heating, it is preferred to keep the metal foil with the dispersion at the volatile temperature of the solvent to dry the dispersion, and then keep the dry coating at a temperature exceeding the volatile temperature of the solvent, and then bake the powder. Specifically, it is preferred to keep the metal foil with the dispersion at a temperature above the boiling point of the solvent, and then bake the powder. "Volatility temperature of the solvent" is preferably the boiling point of the solvent ± 50 ° C, more preferably a temperature above the boiling point of the solvent, and further preferably a temperature below the boiling point of the solvent + 50 ° C. Drying temperature means the temperature of the dry environment. During drying, the solvent does not need to be completely evaporated, but it only needs to be evaporated to a degree that the shape of the layer after drying is stable. Specifically, the amount of solvent to be evaporated is preferably 50% by mass of the solvent contained in the dispersion.

Drying can be performed in one stage at a fixed temperature, or in two or more stages at different temperatures. As drying methods, there are: a method using an oven, a method using a ventilation drying furnace, and a method of irradiating with heat rays such as infrared rays. Drying can be performed under any state of normal pressure or reduced pressure. In addition, the drying environment can be any of an oxidizing gas environment (oxygen, etc.), a reducing gas environment (hydrogen, etc.), and an inert gas environment (helium, neon, argon, nitrogen, etc.). The drying temperature is preferably 50 to 280°C, and more preferably 120 to 260°C. The drying time is preferably 0.1 to 30 minutes, and more preferably 0.5 to 20 minutes. If the dispersion is dried under the above conditions, higher productivity can be maintained and the present multilayer bodies 1 and 2 can be manufactured better.

As a method of baking, there can be cited a method using an oven, a method using a ventilation drying furnace, and a method of irradiating heat rays such as infrared rays. As a method of baking, since the powder can be baked in a short time and the size is relatively compact, the method of irradiating far-infrared rays is preferred. In addition, as a method of baking, a method of combining infrared heating with hot air heating can also be used. Regarding the effective band of far-infrared rays, in order to promote uniform baking of the powder, it is preferably 2 to 20 μm, and more preferably 3 to 7 μm. Furthermore, in order to improve the smoothness of the surface of the obtained laminate 1 and 2, the dried product of the dispersion can be pressurized using a heating plate, a heating roller, etc.

The baking can be carried out under normal pressure or reduced pressure. In addition, the baking environment can be any of an oxidizing gas environment, a reducing gas environment, and an inert gas environment. However, from the perspective of suppressing the oxidation degradation of the metal foil and the formed F layer, the baking environment is preferably a reducing gas environment or an inert gas environment. The baking temperature can be set according to the type of F polymer, preferably 180°C to 400°C, more preferably 200°C to 380°C, and further preferably 220°C to 370°C. The baking temperature refers to the temperature of the baking environment. The baking time is preferably 30 seconds to 30 minutes, more preferably 1 to 15 minutes. If the powder is baked under this condition, the baking of the powder will be promoted, thereby improving the productivity of the laminates 1 and 2, and it is easy to suppress the generation of hydrofluoric acid caused by the decomposition of the F polymer.

Furthermore, when the D50 of the powder is set to A and the ten-point average roughness of the surface of the metal foil is set to B, B/A is preferably 0.1 to 1.5, and more preferably 0.3 to 1.3. If B/A is in the above range, the anchoring effect of the F layer on the surface of the metal foil (metal foil layers 1 and 2) can be more significantly exerted. The specific value of the D50 of the powder is preferably 0.05 to 6 μm, and more preferably 0.2 to 3 μm. In this range, the fluidity and dispersibility of the powder become good, and the electrical properties (low dielectric constant, etc.) or heat resistance of the F layer are most easily manifested. The D90 of the powder is preferably 8 μm or less, and more preferably 5 μm or less. In this range, the fluidity and dispersibility of the powder become good, and the electrical properties (low dielectric constant, etc.) or heat resistance of the F layer are most likely to be manifested. In addition, if the powder is the above-mentioned D50 and D90, it is easier to produce the anchoring effect of the F layer on the surface of the metal foil (metal foil layers 1 and 2). The sparse packing bulk density of the powder is preferably 0.05 g/mL or more, and more preferably 0.08 to 0.5 g/mL. The dense packing bulk density of the powder is preferably 0.05 g/mL or more, and more preferably 0.1 to 0.8 g/mL. When the sparse packing bulk density or the dense packing bulk density is in the above range, the powder has excellent operability.

The powder particles of the F polymer preferably contain the F polymer. The content of the F polymer in the powder particles is preferably 80% by mass or more, and more preferably 100% by mass. Other components that may be contained in the powder particles include: aromatic polyester, polyamide imide, thermoplastic polyimide, polyphenylene ether, and polyphenylene ether.

The solvent in the dispersion is a compound that is liquid at 25°C, and may be an aqueous solvent or a non-aqueous solvent. The solvent is preferably water, amide, alcohol, sulfone, ester, ketone or glycol ether, more preferably water, ketone or amide, and further preferably ketone or amide. The solvent may be used alone or in combination of two or more. Specific examples of solvents include: water, methanol, ethanol, isopropyl alcohol, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, diethyl ether, dioxane, ethyl lactate, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isopropyl ketone, cyclopentanone, cyclohexanone, ethylene glycol monoisopropyl ether, cellulose (methyl cellulose, ethyl cellulose, etc.). As for the solvent, from the viewpoint of enhancing the wettability of the surface of the metal foil and the F polymer so that the hydroxyl groups and/or metal atoms on the surface of the metal foil and the oxygen-containing polar groups of the F polymer interact better, a polar solvent is preferred, preferably water, amide or ketone, more preferably water, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, cyclohexanone or methyl ethyl ketone.

The dispersion liquid preferably further contains a fluorine-based dispersant. The fluorine-based dispersant is a compound that has the function of chemically and/or physically adsorbing on the surface of the powder particles to stably disperse the powder particles in the solvent. The dispersion liquid containing the fluorine-based dispersant further improves the dispersibility of the powder, enhances the wettability of the surface of the metal foil and the F polymer, and thus facilitates the oxide and/or metal atoms on the surface of the metal foil to interact highly with the oxygen-containing polar groups of the F polymer. The fluorine-based dispersant is preferably a compound (surfactant) having a hydrophobic part and a hydrophilic part containing fluorine atoms, more preferably a fluorine-containing polyol, a fluorine-containing polysilicone or a fluorine-containing polyether, and further preferably a fluorine-containing polyol. Furthermore, the fluorine-based dispersant is preferably a non-ionic polymer compound. The fluorine-based dispersant has a high interaction with the above-mentioned solvent, and thus it is easy to improve the coating film forming properties (thickness ratio, adhesion, transparency, etc.) of the dispersion.

Unlike F polymer, fluorinated polyol is a polymer polyol having hydroxyl groups and fluorine atoms. In addition, part of the hydroxyl groups of the polymer polyol can be chemically modified. As fluorinated polyol, there can be listed compounds having a main chain including a carbon chain derived from an ethylenically unsaturated monomer, and a fluorinated hydrocarbon group and a hydroxyl group as a side chain branched from the main chain. In the case of using a dispersion containing the fluorinated polyol, the decomposition product of the fluorinated polyol when the dispersion is applied and heated easily forms an oxide on the surface of the metal foil, thereby making it easy to make the metal foil (metal foil layers 1 and 2) and the polymer layer more firmly bonded.

The fluorinated polyol is preferably a copolymer comprising a unit based on a fluorinated (meth)acrylate having a polyfluoroalkyl group or a polyfluoroalkenyl group, and a unit based on a hydrophilic (meth)acrylate having a polyoxyalkylene group or a hydroxyalkylene group. In addition, (meth)acrylate is a general term for acrylate, methacrylate, and acrylate derivatives in which the hydrogen atom at the α position of acrylate is substituted by other atoms or atomic groups.

Specific examples of fluorine-containing (meth)acrylates include: _CH2 =CHCOO( _CH2 ) ₂ ( _CF2 ) _4F , _CH2 =C( _CH3 )COO( _CH2 ) ₂ ( _CF2 )4F, _CH2 =CClCOO( _CH2 ) ₂ ( _CF2 ) _4F , _CH2 =CHCOO( _CH2 ) ₂ ( _CF2 ) _6F , _CH2 = _C ( _CH3 ) _COO ( _CH2 ) ₂ (CF2) _6F , _CH2 =CHCOO( _CH2 )4OCF( _CF3 )(C(CF( _CF3 ) ₂ )(=C( _CF3 ) ₂ ), _CH2 =CHCOO( _CH2 )4OCF( _CF3 )(C(CF(CF3) ₂ ))(=C( _{CF3 ) 2} )(CF(CF ₃ ) ₂ ), CH ₂ =C(CH ₃ )COO(CH ₂ ) ₂ NHCOOCH(CH ₂ OCH ₂ CH ₂ (CF ₂ ) ₆ F) ₂ , CH ₂ =C(CH ₃ )COO(CH ₂ ) ₂ NHCOOCH(CH ₂ OCH ₂ (CF ₂ ) ₆ F) ₂ , CH ₂ =C(CH ₃ )COO(CH ₂ ) ₃ N HCOOCH(CH ₂ OCH ₂ (CF ₂ ) ₆ F) ₂ .

Specific examples of hydrophilic (meth)acrylates include _CH2 =CHCOO( _CH2 ) _2OH , _CH2 =C( _CH3 )COO( _CH2 )2OH, CH2= _CHCOO (CH2) ₂ (OCH2CH2) _10OH , CH2=CHCOO( _CH2 ) ₄ ( _OCH2CH2 )10OH, _CH2 =C( _CH3 ) _COO (CH2)2 ₍ OCH2CH2) _10OH , H2=C( _CH3 )COO( _CH2 ) ₄ (OCH2CH2) _10OH , _{CH2=CHCOO(CH2)2(OCH2CH(CH3))10OH, CH2 = C ( CH3 ) COO ( CH2 ) 4} (OCH2CH2) _10OH , CH2=CHCOO( _{CH2 ) 2} (OCH2CH( _CH3 ))10OH, _CH2 =C(CH3)COO(CH2) ₄ (OCH2CH2) _{10OH .} )COO(CH ₂ ) ₂ (OCH ₂ CH(CH ₃ )) ₁₀ OH, CH ₂ =CHCOO(CH ₂ ) ₂ (OCH ₂ CH ₂ ) ₂₃ OH, CH ₂ =C(CH ₃ )COO(CH ₂ ) ₂ (OCH ₂ CH ₂ ) ₂₃ OH.

The fluorine-containing polyol may only contain units based on fluorine-containing (meth)acrylate and units based on hydrophilic (meth)acrylate, and may further contain other units. The fluorine content of the fluorine-containing polyol is preferably 10-45% by mass, more preferably 15-40% by mass. In addition, the weight average molecular weight of the fluorine-containing polyol is preferably 2000-80000, more preferably 6000-20000.

As fluorinated polysiloxanes, polyorganosiloxanes containing a C-F bond as part of the side chain can be cited. In addition, as fluorinated polyethers, compounds in which a part of the hydrogen atoms of polyoxyalkylene alkyl ethers are replaced by fluorine atoms can be cited. Furthermore, fluorinated polyethers also include monoalcohols of the above compounds.

Furthermore, the dispersion may also contain other materials. The other materials may or may not be dissolved in the dispersion. The other materials may be non-hardening resins or hardening resins. As non-hardening resins, hot-melt resins and non-melting resins can be listed. As hot-melt resins, thermoplastic polyimide can be listed. As non-melting resins, hardened materials of hardening resins can be listed.

As the curable resin, there can be listed: polymers having reactive groups, oligomers having reactive groups, low molecular weight compounds, and low molecular weight compounds having reactive groups. As the reactive groups, there can be listed carbonyl-containing groups, hydroxyl groups, amino groups, and epoxy groups. Examples of the curable resin include epoxy resin, thermosetting polyimide, polyamide as a precursor of polyimide, acrylic resin, phenolic resin, polyester resin, polyolefin resin, modified polyphenylene ether resin, multifunctional cyanate resin, multifunctional cis-1,1-diimide-cyanate resin, multifunctional cis-1,1-diimide resin, vinyl ester resin, urea resin, diallyl phthalate resin, melanin resin, guanamine resin, and melamine-urea co-condensation resin.

As specific examples of epoxy resins, various types of epoxy resins (naphthalene type, cresol novolac type, bisphenol A type, bisphenol F type, bisphenol S type, alicyclic type, aliphatic chain type, cresol novolac type, phenol novolac type, alkylphenol novolac type, aralkyl type, biphenol type, etc.) can be cited. As bis-cis-butylene diimide resins, the resin composition (BT Resin) described in Japanese Patent Laid-Open No. 7-70315 and the resin described in International Publication No. 2013/008667 can be cited. Polyamide generally has a reactive group that can react with the oxygen-containing polar group of the F polymer. Examples of diamines and polycarboxylic acid dianhydrides that form polyamide include compounds described in [0020] of Japanese Patent No. 5766125, [0019] of Japanese Patent No. 5766125, [0055] and [0057] of Japanese Patent Application Laid-Open No. 2012-145676, and the like.

As the hot melt resin, there can be listed thermoplastic resins such as thermoplastic polyimide and hot melt hardened materials of hardening resins. As the thermoplastic resin, there can be listed polyester resin, polyolefin resin, styrene resin, polycarbonate, thermoplastic polyimide, polyarylate, polysulfide, polyarylether sulfide, aromatic polyamide, aromatic polyether amide, polyphenylene sulfide, polyarylether ketone, polyamide imide, liquid crystalline polyester, polyphenylene ether, preferably thermoplastic polyimide, liquid crystalline polyester or polyphenylene ether. In addition, other related materials include thixotropic agents, defoaming agents, inorganic fillers, reactive alkoxysilanes, dehydrating agents, plasticizers, weathering agents, antioxidants, thermal stabilizers, lubricants, antistatic agents, whitening agents, coloring agents, conductive agents, mold release agents, surface treatment agents, viscosity regulators, and flame retardants.

The viscosity of the dispersion is preferably 50 to 10000 mPa·s, more preferably 75 to 1000 mPa·s, and further preferably 100 to 500 mPa·s. In this case, not only the dispersion is excellent in dispersibility, but also its coating property or compatibility with varnishes of different types of resin materials is excellent. In addition, the thixotropic ratio of the dispersion is preferably 1.0 to 2.2, more preferably 1.4 to 2.2, and further preferably 1.5 to 2.0. In this case, not only the dispersion is excellent in dispersibility, but also the homogeneity of the F layer is easily improved. In addition, the trip ratio is calculated by dividing the viscosity of the dispersion measured at a rotation speed of 30 rpm by the viscosity of the dispersion measured at a rotation speed of 60 rpm.

In the method of hot-pressing a film containing an F polymer on the surface of a metal foil, if the film containing an F polymer is hot-pressed on the surface of a metal foil, an F layer is formed, and the present laminated bodies 1 and 2 having the F layers directly contacting the surfaces of the metal foil layers 1 and 2 containing the metal foil can be obtained. The film can be produced by forming the F polymer itself or a composition containing the F polymer into a film by extrusion molding, inflation molding, etc. Specifically, the production of the laminate is carried out through the following steps: a preheating step, which is to heat the pre-laminated body formed by superimposing the film on the surface of the metal foil while conveying it without applying pressure in the thickness direction (lamination direction); and a heat-pressing bonding step, which is to heat the pre-laminated body while applying pressure in the thickness direction (lamination direction) for bonding. The pre-laminated body is a state where the metal foil and the film are in close contact with each other, but are not yet connected (pressed).

Furthermore, before forming the pre-layered body, the film may be pre-heated at a temperature of 100°C to less than 250°C (preferably 180°C to less than 250°C). If the pre-heating is performed, the shrinkage of the film in the preheating step and the heat-pressing bonding step can be reduced, and as a result, the warp of the laminated body can be reduced. In addition, before forming the pre-layered body, the surface of the film (the surface on the metal foil side) may be subjected to surface treatment such as corona discharge treatment and plasma treatment. If the surface treatment is performed in advance, the amount of oxygen-containing polar groups existing on the surface of the film can be increased, and in the obtained laminate, the bonding strength of the F layer to the metal foil layers 1 and 2 can be further improved.

In the preheating step, the pre-deposited layer is heated by the preheating mechanism without applying pressure in the lamination direction (thickness direction) before the pressing in the subsequent heat-pressing bonding step. The preheating mechanism may be a contact method in which the heat source contacts the pre-deposited layer, or a non-contact method in which the pre-deposited layer is heated without contact. In terms of making it easy to make the metal foil and the film close to each other, the preheating mechanism is preferably a contact method. Specifically, it is preferably a method in which the pre-deposited layer is transported in a state in which it contacts the heated metal roller. The temperature of the pre-layered body (preheating temperature) immediately before the pressurization in the heat-pressing bonding step is preferably 20°C lower than the melting temperature of the F polymer, and more preferably higher than the melting temperature of the F polymer. The preheating temperature is preferably below the heat-pressing bonding temperature. If the preheating temperature is within the above range, shrinkage or rupture of the film can be well prevented.

In the preheating step, the pre-deposited layer can be heated continuously or intermittently. The conveying time (preheating time) from the position where the pre-deposited layer is conveyed to the time before the pre-deposited layer is pressed in the heat-pressing bonding step is preferably 10 to 30 seconds. If the preheating time is within the above range, the shrinkage or rupture of the film can be well prevented, and in the obtained laminate, the adhesion of the F layer to the metal foil layers 1 and 2 is increased. When the preheating step is performed using a contact-based preheating mechanism, if the preheating time is within the above range, the temperature of the pre-deposited layer becomes the same temperature as the surface temperature of the heat source that the pre-deposited layer contacts.

The hot press bonding step is preferably performed continuously using a hot press bonding device having one or more hot press bonding mechanisms. The hot press bonding mechanism refers to a mechanism that performs press bonding by heating the pre-deposited layer while applying pressure. As the hot press bonding mechanism, a hot roller press bonding device having one or more metal rollers can be preferably used. In the hot roller press bonding device, the pre-deposited layer is heated by contact with the metal roller when passing through a pair of metal rollers heated to a specific temperature, and is subjected to pressure in the thickness direction, so that the film is pressed onto the metal foil. It can also be configured such that the pre-deposited layers sequentially pass through a plurality of pairs of metal rollers.

The surface temperature of the metal roller for pressurizing the pre-deposited body (temperature for hot pressing) is preferably above the melting temperature of the F polymer, more preferably above 400°C. In this case, good bonding strength of the F layer to the metal foil layers 1 and 2 can be obtained, so that peeling is not easy to occur. The pressure between a pair of metal rollers for pressurizing the pre-deposited body (pressure for hot pressing) is preferably 98 to 1470 N/cm in roller linear pressure expressed by the load per 1 cm width added to the roller. In this case, the film is not easy to break during hot pressing, and good bonding strength of the F layer to the metal foil layers 1 and 2 can be obtained, so that peeling is not easy to occur.

The moving speed (thermal pressure bonding speed) of the pre-laminated body when passing through a pair of metal rollers is preferably 0.5 m/min or more, more preferably 1 m/min or more. In this case, thermal pressure bonding can be fully performed, and the productivity of the laminated bodies 1 and 2 can be further improved. The thermal pressure bonding speed is preferably 8 m/min or less. In this case, it is easy to make the F layer and the metal foil layers 1 and 2 firmly bonded.

The film may also be a laminated film having a heat-resistant resin film on the side of the film (base film) containing the F polymer opposite to the metal foil. The heat-resistant resin film contains a heat-resistant resin and may contain additives etc. as needed. The content of the heat-resistant resin in the heat-resistant resin film is preferably 50% by mass or more, and more preferably 80% by mass or more, from the viewpoint of improving the heat resistance of the heat-resistant resin film.

Examples of heat-resistant resins include polyimide (aromatic polyimide, etc.), polyarylate, polysulfone, polyarylate (polyethersulfone, etc.), aromatic polyamide, aromatic polyetheramide, polyphenylene sulfide, polyaryletherketone, polyamideimide, and liquid crystal polyester. Heat-resistant resins are preferably thermosetting resins in terms of easy acquisition of higher heat resistance. Examples of thermosetting resins include thermosetting polyimide, epoxy resin, and acrylic resin. From the perspective of improving the electrical properties of the laminate, thermosetting polyimide is preferred as a thermosetting resin. As the thermosetting polyimide, aromatic polyimide is preferred, and fully aromatic polyimide produced by polycondensation of aromatic dicarboxylic acid and aromatic diamine is more preferred.

As additives, inorganic fillers with lower dielectric constant and dielectric loss tangent are preferred. As the inorganic filler, there can be listed: silicon dioxide, clay, talc, calcium carbonate, mica, diatomaceous earth, aluminum oxide, zinc oxide, titanium oxide, calcium oxide, magnesium oxide, iron oxide, tin oxide, antimony oxide, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, alkaline magnesium carbonate, magnesium carbonate, zinc carbonate, barium carbonate, carbon sodium aluminate, aluminum carbonate Magnesium, calcium sulfate, barium sulfate, calcium silicate, montmorillonite, bentonite, activated clay, sepiolite, imogolite, sericite, glass fiber, glass beads, silica hollow spheres, carbon black, carbon nanotubes, carbon nanohorns, graphite, carbon fiber, glass hollow spheres, carbon hollow spheres (Carbon balloons), wood powder, zinc borate. In addition, the inorganic filler may be used alone or in combination of two or more.

In the present laminates 1 and 2, the peeling strength of the F layer with respect to the metal foil layers 1 and 2 is preferably 10 N/cm or more, and more preferably 15 N/cm or more. Furthermore, the upper limit of the peeling strength is usually 20 N/cm. The curvature of the present laminates 1 and 2 is preferably 25% or less, and more preferably 7% or less. In this case, the operability when the present laminates 1 and 2 are processed into a printed wiring board and the transmission characteristics of the obtained printed wiring board are excellent. The dimensional change rate of the present laminates 1 and 2 is preferably ±1% or less, and more preferably ±0.2% or less. In this case, it is easy to process the present laminates 1 and 2 into a printed wiring board and further multilayer it.

The water contact angle of the surface of the F layer is preferably 70 to 100°, more preferably 70 to 90°. In this case, the adhesion between the F layer and other substrates is better. If the above range is above the lower limit, the electrical characteristics of the laminated bodies 1 and 2 when processed into a printed wiring board are better. The thickness of the F layer is preferably 1 to 50 μm, more preferably 5 to 15 μm. Within this range, it is easy to balance the electrical characteristics when the laminated bodies 1 and 2 are processed into a printed wiring board and the warp suppression effect of the laminated body. Furthermore, when the present multilayer bodies 1 and 2 have F layers on both surfaces of the metal foil layers 1 and 2, the composition and thickness of the F layers are preferably the same in order to suppress the warping of the present multilayer bodies 1 and 2.

The dielectric constant of the F layer is preferably 1.98 or less, and more preferably 1.95 or less. The lower limit of the dielectric constant of the F layer is usually 1.50. The dielectric loss tangent of the F layer is preferably 0.0024 or less, and more preferably 0.0019 or less. The lower limit of the dielectric constant of the F layer is usually 0.0005. In this case, the present multilayer bodies 1 and 2 can be preferably used in printed wiring boards that require low dielectric constants. In addition, the dielectric constant and dielectric loss tangent of the F layer are values measured using a network analyzer as a measuring instrument and a cavity resonator perturbation method at a measuring frequency of 10 GHz.

The present laminates 1 and 2 can be processed into a printed wiring board. For example, if a method of processing the metal foil layers 1 and 2 of the present laminates 1 and 2 into a conductor circuit (pattern circuit) of a specific pattern by etching or the like, or a method of processing the present laminates 1 and 2 into a pattern circuit by electrolytic plating (semi-additive process (SAP process), modified semi-additive process (MSAP process) etc.), the present laminates 1 and 2 can be used to manufacture a printed wiring board. In the manufacture of a printed wiring board, after forming the pattern circuit, an interlayer insulating film can be formed on the pattern circuit, and a conductor circuit can be further formed on the interlayer insulating film. The interlayer insulating film can be formed by the above-mentioned dispersion. In the manufacture of printed wiring boards, a solder resist may be laminated on the pattern circuit. The solder resist may be formed by the above-mentioned dispersion. In the manufacture of printed wiring boards, a cover film may be laminated on the pattern circuit. The cover film may be formed by the above-mentioned dispersion.

The manufacturing method of the composite laminate (the present composite) of the present invention is as follows: at least a portion of the metal foil layer of a specific laminate (metal foil with F layer) is removed, and the prepreg is bonded to the exposed polymer layer to obtain a composite laminate having at least a polymer layer and a prepreg layer. If the entire metal foil layer is removed, a composite laminate having a two-layer structure of a polymer layer and a prepreg layer can be obtained. In addition, if a portion of the metal foil layer is removed and a circuit pattern is formed, a composite laminate having a three-layer structure of a polymer layer, a prepreg layer, and a circuit pattern sandwiched therebetween can be obtained. The latter composite laminate can be preferably used as a printed wiring board. The laminate used in the manufacture of the composite laminate has a metal foil layer having a surface with a ten-point average roughness of 0.1 μm or more, and an F layer laminated on the surface.

The surface of the metal foil layer has a ten-point average roughness of more than 0.1 μm and has irregular micro-concavities and convexities. The F layer formed on the surface transfers the surface shape of the metal foil layer to the contact surface with the metal foil layer. Therefore, the contact surface of the F layer exposed by removing the metal foil layer has irregular micro-concavities and convexities corresponding to the surface shape of the metal foil layer. In the present invention, since the prepreg is bonded to the contact surface of the surface property to obtain a composite laminate, it is considered that a higher anchoring effect of the prepreg on the contact surface of the F layer will be produced. It is inferred that as a result, a higher bonding force (peeling strength) is exhibited between the F layer and the prepreg layer. The above effects will be clearly shown in the preferred aspects of the present invention described below.

The aspects of the F polymer in the manufacturing method of the present composite, including preferred aspects, are the same as the aspects of the F polymer in the present laminate. The aspects of the metal constituting the metal foil layer in the manufacturing method of the present composite, including preferred aspects, are the same as the aspects of the metal constituting the metal foil layer in the present laminate.

The ten-point average roughness of the surface of the metal foil layer in the manufacturing method of the present composite is greater than or equal to 0.1 μm, preferably 0.3 μm. The above ten-point average roughness is preferably less than or equal to 7 μm, more preferably less than or equal to 2.5 μm, and further preferably less than or equal to 2 μm. Furthermore, if the ten-point average roughness is within the above range, the surface roughness of the metal foil layer will not be too large, so even when the present composite is processed into a printed wiring board, the increase in transmission loss can be suppressed. Furthermore, when a prepreg is laminated, the matrix resin of the prepreg is compatible with the F polymer, which makes it easy to further improve the adhesion between the layers.

When the metal foil layer in the manufacturing method of the present composite has a roughening layer, the ten-point average roughness of the surface can be adjusted by setting the size of the metal particles, the number of metal particles, etc. The roughening layer is preferably formed by precipitating (electrodepositing) metal particles on the substrate layer by electroplating with the substrate layer as the cathode. In this case, the electroplating amount such as the size of the metal particles and the number of metal particles can be mainly controlled by adjusting the current density and the electroplating time. The conditions for electroplating can be the same as those for electroplating of the present laminate.

Furthermore, the surface of the metal foil layer may be subjected to a roughening treatment such as dry etching or wet etching to adjust the ten-point average roughness of the surface to the above range. In addition, from the perspective of improving various properties, the metal foil layer may have at least one layer of a heat-resistant treatment layer, a rust-proof treatment layer, and a chromate treatment layer. When the metal foil layer is a laminated structure, the layers may be arranged on the surface of the roughening treatment layer on the opposite side of the substrate layer, or between the roughening treatment layer and the metal foil. Furthermore, when forming the heat-resistant treatment layer, the rust-proof treatment layer, or the chromate treatment layer, a known method may be adopted. Furthermore, when the heat-resistant treatment layer, the rust-proof treatment layer or the chromate treatment layer constitutes the outermost layer of the metal foil layer, its surface constitutes the surface of the metal foil layer. The thickness of the metal foil layer can be the same as the thickness of the metal foil layer of the present laminate.

The aspects of the F layer in the manufacturing method of the present composite, including its preferred aspects and its formation method, are the same as those in the present multilayer body.

The removal of the metal foil layer in the manufacturing method of the present composite is preferably performed by wet etching. By wet etching, it is possible to prevent damage to the tiny uneven shapes of the contact surface transferred to the F layer, and to accurately and fully remove the useless parts of the metal foil layer. In addition, wet etching is preferably performed using an acid solution. In the case where the F polymer has a hydrolyzable acid anhydride residue as the above-mentioned oxygen-containing polar group, since the oxygen-containing polar group is activated by the acid solution, the adhesion between the F layer and the prepreg layer is easily further improved. Here, as an example of the activation of the oxygen-containing polar group, the conversion of the acid anhydride group to the 1,2-dicarboxylic acid group can be cited. As the acid solution, an aqueous solution of an inorganic acid such as hydrochloric acid, dilute nitric acid or hydrofluoric acid can be used.

The prepreg is a sheet-shaped substrate formed by impregnating a matrix resin into a base material (tow, woven fabric, etc.) of reinforcing fibers (glass fiber, carbon fiber, etc.). The matrix resin may be a thermoplastic resin or a thermosetting resin. That is, the prepreg layer is a layer formed by the prepreg. Regarding the prepreg layer, if the matrix resin is curable, it is a layer containing a cured product of the matrix resin, and if the matrix resin is thermoplastic, it is a layer containing a molten solidified product of the matrix resin. As thermosetting resins, the resins listed in the description of the above dispersion can be listed, preferably epoxy resin, polyphenylene ether, polyphenylene oxide or polybutadiene. The polyphenylene ether is preferably a modified polyphenylene ether, and more preferably a polyphenylene ether having a vinyl group. As the thermoplastic resin, the resins listed in the description of the above dispersion can be cited. The base resin can be used alone or in combination of two or more.

As the matrix resin of the prepreg, epoxy resin, polyphenylene ether, polyphenylene oxide or polybutadiene is preferred in terms of processability. In addition, when the matrix resin is a thermosetting resin, it is preferred that a curing agent is included in the prepreg, and it is more preferred that a curing agent includes a curing agent having three or more curing groups (isocyanate groups, blocked isocyanate groups, etc.) in one molecule. As the matrix resin, a resin having fluorine atoms can also be used. As such a resin, F polymer, polyimide having fluorine atoms, and epoxy resin having fluorine atoms can be listed. As preferred aspects of the base resin, there can be cited an aspect including only a base resin having no fluorine atoms, and an aspect including a base resin having no fluorine atoms and a base resin having fluorine atoms.

As a reinforcing fiber sheet, there can be listed a reinforcing fiber bundle containing a plurality of reinforcing fibers, a fabric (cloth) formed by weaving the reinforcing fiber bundle, a unidirectional reinforcing fiber bundle formed by unidirectionally spun a plurality of reinforcing fibers, a unidirectional fabric containing the unidirectional reinforcing fiber bundle, or a laminate of a plurality of reinforcing fiber bundles formed by combining these. As the reinforcing fiber, a continuous long fiber with a length of 10 mm or more is preferred. The reinforcing fiber does not need to be continuous in the entire length in the length direction or the entire width in the width direction of the reinforcing fiber sheet, and can be disconnected in the middle. Reinforced fibers can also be subjected to surface treatments such as silane coupling agent treatment.

Examples of reinforcing fibers include inorganic fibers, metal fibers, and organic fibers. Examples of inorganic fibers include carbon fibers, graphite fibers, glass fibers, silicon carbide fibers, silicon nitride fibers, alumina fibers, silicon carbide fibers, and boron fibers. Examples of metal fibers include aluminum fibers, brass fibers, and stainless steel fibers. As organic fibers, there can be listed aromatic polyamide fibers, polyarylamide fibers, poly(p-phenylene benzoxazole) (PBO) fibers, polyphenylene sulfide fibers, polyester fibers, acrylic fibers, nylon fibers, polyethylene fibers, etc. The reinforcing fibers may be used alone or in combination of two or more. The reinforcing fibers used in printed circuit board materials are preferably glass fibers.

The method of bonding the prepreg to the F layer is preferably a method of bonding the prepreg to the contact surface of the F layer exposed to at least a portion of the laminate and performing heat-press bonding. The temperature of heat-press bonding is preferably below the melting temperature of the F polymer, more preferably 120 to 300°C, and further preferably 160 to 220°C. Within this range, thermal degradation of the prepreg can be suppressed and the polymer layer and the prepreg layer can be firmly bonded. The pressure of heat-press bonding is preferably 0.2 MPa. In addition, the pressure is preferably 10 MPa or less, and more preferably 4 MPa or less. Within this range, damage to the prepreg can be suppressed and the F layer and the prepreg layer can be more firmly bonded. Furthermore, when the prepreg is heat-pressed and bonded to the contact surface of the F layer at the heat temperature or the press-bonding pressure, the prepreg layer entering the F layer is further dissolved and integrated with the F polymer by the anchoring effect, thereby making it easier to improve the bonding strength.

Hot pressing is preferably performed in a reduced pressure environment, and more preferably at a vacuum of less than 20 kPa. Within this range, the mixing of bubbles in the interface between the F layer and the prepreg layer can be suppressed, thereby suppressing the deterioration of the composite due to oxidation. In addition, it is better to increase the temperature after reaching the above vacuum during hot pressing. If it is performed in this way, the F layer will be pressed in a state before softening, that is, before showing a certain degree of fluidity and adhesion, so the generation of bubbles can be prevented.

According to the manufacturing method of the present composite, since the prepreg layer is laminated on the F layer with strong adhesion to the roughness of the metal foil layer, the F layer can be directly bonded to the prepreg layer without performing a hydrophilic treatment on the surface of the exposed F layer (contact surface). The hydrophilic treatment is a treatment to reduce the contact angle of water on the surface of the exposed F layer. Specifically, plasma treatment, radiation curing treatment or treatment with a silane coupling agent can be listed. In the present composite, the peeling strength of the F layer to the prepreg layer is preferably 10 N/cm or more, and more preferably 15 N/cm or more. Furthermore, the upper limit of the peel strength is usually 20 N/cm. The curvature of the composite is preferably 25% or less, and more preferably 7% or less. In this case, the transmission characteristics of the composite (printed wiring board) are excellent. The dimensional change rate of the composite is preferably ±1% or less, and more preferably ±0.2% or less. In this case, it is easy to multi-layer the composite.

In the manufacturing method of the present composite, a processed laminated body formed by removing a portion of the metal foil layer of the laminated body and forming a metal circuit layer (circuit pattern) from the metal foil layer is useful as a printed circuit board having excellent reflow resistance. For example, a multilayer printed circuit board having a multilayer structure of the printed circuit board and having an F layer on the outermost layer has excellent heat resistance. Specifically, even at 288°C, it is not easy to produce bulging at the interface of the prepreg layer or peeling at the interface of the metal circuit layer. In particular, when the F layer is at a specific thickness (1 to 15 μm, especially 3 to 9 μm), this tendency tends to become obvious. Furthermore, the multi-layer printed circuit board having the multi-layer structure of the printed circuit board and having the prepreg layer as the outermost layer also has excellent heat resistance. Specifically, even at 300°C, it is not easy to produce bulging at the interface of the prepreg layer or peeling at the interface of the metal circuit layer. In particular, when the F layer is at a specific thickness (1 to 15 μm, especially 3 to 9 μm), this tendency tends to become obvious.

Furthermore, according to the present invention, a method for manufacturing a laminate can be provided, which comprises removing at least a portion of the metal foil of a laminate having a metal foil layer with a surface having a ten-point average roughness of 0.1 μm or more and an F layer laminated on the surface (metal foil with F layer), applying a solder resist on the exposed F layer, and hardening it to form a solder resist layer, thereby at least the F layer and the solder resist layer are laminated. The aspect of removing at least a portion of the metal foil (metal foil layer), F polymer, F layer, laminate, and the metal foil layer of the laminate in the manufacturing method also includes a preferred range, which is the same as the aspect of the manufacturing method of the present composite.

The solder resist may be a known solder resist. Moreover, the application and curing of the solder resist may be appropriately determined according to the type of solder resist used. In this manufacturing method, the exposed F layer is preferably treated with an acid solution on its surface and the solder resist is directly applied and cured in this state. In this case, in the formation of the solder resist layer, it is easier to form a solder resist layer with better adhesion than in the case of performing surface treatment (polishing and grinding) after acid treatment.

Furthermore, in the manufacturing method of the polymer film of the present invention, the entire metal foil layer of the above-mentioned laminate (metal foil with F layer) can be removed, and the remaining single body F layer can be used as a polymer film. The polymer film can be used as a bonding layer for bonding two substrates, an interlayer insulating film, a solder resist layer, a cover film, etc.

The above description is directed to the laminate and its manufacturing method, the manufacturing method of the composite laminate, and the manufacturing method of the polymer film of the present invention, but the present invention is not limited to the configuration of the above-mentioned embodiments. For example, the laminate of the present invention can be supplemented with any other configuration in the configuration of the above-mentioned embodiments, and can also be replaced with any configuration that performs the same function. Furthermore, the manufacturing method of the laminate, the manufacturing method of the composite laminate, and the manufacturing method of the polymer film of the present invention can be supplemented with any other steps in the configuration of the above-mentioned embodiments, and can also be replaced with any steps that perform the same function. [Example]

The present invention is specifically described below with reference to the following embodiments, but the present invention is not limited to these embodiments. 1. Preparation of each component and each member [F polymer] F polymer 1: A copolymer comprising, in sequence, 98.0 mol%, 0.1 mol%, and 1.9 mol% of a TFE-based unit, a NAH-based unit, and a PPVE-based unit (melting temperature: 300°C; melt viscosity at 380°C: 3×10 ⁵ Pa・s) F polymer 2: A copolymer without oxygen-containing polar groups comprising, in sequence, 98.0 mol%, and 2.0 mol% of a TFE-based unit and a PPVE-based unit (melting temperature: 305°C; melt viscosity at 380°C: 3×10 ⁵ Pa・s) F polymer 3: A copolymer without functional groups comprising, in sequence, 97.5 mol%, and 2.5 mol% of a TFE-based unit and a PPVE-based unit (melting temperature: 305°C; melt viscosity at 380°C: 3×10 ⁵ Pa・s)

[Powder] Powder 1: powder containing F polymer 1 (D50: 2.6 μm; D90: 7.1 μm) Powder 2: powder containing F polymer 2 (D50: 3.5 μm; D90: 9.2 μm) Powder 3: powder containing F polymer 2 (D50: 1.8 μm; D90: 4.9 μm) Powder 4: powder containing F polymer 1 (D50: 1.8 μm; D90: 5.2 μm) Powder 5: powder containing F polymer 3 (D50: 1.9 μm; D90: 5.5 μm) In addition, D50 and D90 were measured by dispersing the powder in water using a laser diffraction-scattering particle size distribution measuring device (manufactured by Horiba, Ltd., LA-920 measuring device).

[Fluorine-based dispersant] FP1: A copolymer of _CH2 =CHCOO( _CH2 ) _4OCF ( _CF3 )(C(CF( _CF3 ) ₂ )(=C( _CF3 ) ₂ ) and _CH2 =CHCOO( _CH2 ) ₄ ( _OCH2CH2 ) _10OH , which is a non-ionic fluorinated polyol [Sheet] Sheet 1: A sheet containing F polymer ₁ (thickness: 10 μm) Sheet 2: A sheet containing F polymer 3 (thickness: 10 μm) [Prepreg] Prepreg 1: A thermosetting resin composition containing a polyphenylene ether resin, glass fiber, and a silica filler

2. Preparation of dispersion liquid (Dispersion liquid 1) 47 parts by mass of N-methyl-2-pyrrolidone (NMP), 2.5 parts by mass of FP1, and 50 parts by mass of powder 1 were placed in a pot, and then zirconia balls were placed in the pot. Then, the pot was rotated at 150 rpm for 1 hour to disperse powder 1 in NMP to prepare dispersion liquid 1. (Dispersion liquid 2) Dispersion liquid 2 was prepared in the same manner as dispersion liquid 1 except that powder 1 was replaced with powder 2.

(Dispersion 3) Dispersion 3 was prepared in the same manner as Dispersion 1 except that Powder 1 was replaced by Powder 3. (Dispersion 4) Dispersion 4 was prepared in the same manner as Dispersion 1 except that Powder 1 was replaced by Powder 4 and the amount of FP1 was changed to 3 parts by mass. (Dispersion 5) Dispersion 5 was prepared in the same manner as Dispersion 1 except that Powder 1 was replaced by Powder 5 and the amount of FP1 was changed to 3 parts by mass.

3. Preparation of Metal Foil (Metal Foil 1) A rolled copper foil (substrate layer) with a thickness of 12 μm was used as a cathode, and electroplating was performed under the following conditions to form a roughening treatment layer on the surface of the rolled copper foil. Thus, Metal Foil 1 was prepared. Subsequently, a heat-resistant treatment layer and a chromate layer were sequentially formed on the surface of the roughening treatment layer. In addition, the thickness of Metal Foil 1 was 15 μm, and the ten-point average roughness of the surface was 0.6 μm. <1st Particle Plating (1)> Liquid composition: Copper sulfate pentahydrate 11 g/L, sulfuric acid 52 g/L Liquid temperature: 22°C Current density: 40 A/ ^dm2 Electrodeposition time: 1 second <1st Particle Plating (2)> Liquid composition: Copper sulfate pentahydrate 19 g/L, sulfuric acid 101 g/L Liquid temperature: 42°C Current density: 4 A/ ^dm2 Electrodeposition time: 3 seconds <2nd Particle Plating> Liquid composition: Copper sulfate pentahydrate 15 g/L, Nickel sulfate hexahydrate 10 g/L, Cobalt sulfate heptahydrate 7 g/L Liquid temperature: 37°C Current density: 30 A/ ^dm2 Electrodeposition time: 1 second

(Metal foil 2) The surface of metal foil 1 was treated with a solution containing 1 volume % of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., "KBM series") under the following conditions to produce metal foil 2. The thickness of metal foil 2 was 15 μm, and the ten-point average roughness of the surface was 0.6 μm. <Treatment conditions> Solution temperature: 20°C Solution pH: 4.5 Treatment time: 3 seconds Number of coatings: 1 time Drying temperature: 110°C Drying time: 30 seconds

(Metal Foil 3) Platinum oxide-coated titanium was used as the anode, and electrolytic copper foil with a ten-point average roughness (Rzjis) of 0.75 μm and a thickness of 12 μm was used as the cathode. Electroplating was performed under the following conditions to form a roughening treatment layer on the surface of the electrolytic copper foil to produce Metal Foil 3. <Plating Conditions> Liquid composition: Copper sulfate pentahydrate 15 g/L, cobalt sulfate heptahydrate 8.5 g/L, nickel sulfate hexahydrate 1.7 g/L pH value: 2.5 Liquid temperature: 38°C Current density: 45 A/dm ² Electroplating time: 1 second Furthermore, the ten-point average roughness of the surface of Metal Foil 3 was 1.0 μm. The surface of the metal foil 3 (roughened layer) was analyzed using a fluorescent X-ray analyzer (ZSX PrimusII, manufactured by Rigaku Co., Ltd.) with a measurement diameter of φ30 mm. The result showed that the ratio of nickel atoms (mass of nickel atoms/mass of total atoms) was 0.06 mass %.

(Metal Foil 4) Metal Foil 4 was produced in the same manner as Metal Foil 3 except that the liquid composition was changed to the following. Liquid composition: copper sulfate pentahydrate 15 g/L, cobalt sulfate heptahydrate 8.5 g/L In addition, the ten-point average roughness of the surface of Metal Foil 4 was 1.0 μm. In addition, the ratio of nickel atoms present on the surface of Metal Foil 4 (roughening treatment layer) measured in the same manner as above was 0.00 mass %. (Metal Foil 5) Metal Foil 5 was produced in the same manner as Metal Foil 3 except that the liquid composition was changed to the following. Liquid composition: copper sulfate pentahydrate 15 g/L, cobalt sulfate heptahydrate 8.5 g/L, nickel sulfate hexahydrate 8.6 g/L In addition, the ten-point average roughness of the surface of the metal foil 5 is 1.0 μm. In addition, the ratio of nickel atoms existing on the surface of the metal foil 5 (roughening treatment layer) measured in the same manner as above is 0.30 mass%.

(Metal foil 6) Metal foil 6 was manufactured by electroplating an electrolytic copper foil to form a roughening layer, and then a heat-resistant layer and a chromate layer were sequentially formed on the roughening layer. The ten-point average roughness of the surface of metal foil 6 was 0.2 μm, and the thickness was 12 μm. (Metal foil 7) Metal foil 7 was manufactured in the same manner as metal foil 6. The ten-point average roughness of the surface of metal foil 7 was 1.2 μm, and the thickness was 18 μm. (Metal foil 8) Metal foil 8 was manufactured in the same manner as metal foil 6. The ten-point average roughness of the surface of metal foil 8 was 7.7 μm, and the thickness was 18 μm.

4. Production of laminated body (Example 1) First, the dispersion 1 is applied to the surface of the metal foil 1 by roll-to-roll coating through a die nozzle to form a liquid coating. Then, the metal foil 1 formed with the liquid coating is passed through a drying furnace at 120°C for 30 minutes to be dried by heating. Thereafter, the dried coating is heated at 380°C for 15 minutes in a nitrogen oven. In this way, a laminated body 1 having a layer F formed on the surface of the metal foil 1 is produced.

(Example 2 (Comparative Example)) Except that the metal foil 1 is replaced by the metal foil 2, a laminate 2 is produced in the same manner as in Example 1. (Example 3 (Comparative Example)) Except that the dispersion 1 is replaced by the dispersion 2, a laminate 3 is produced in the same manner as in Example 1.

(Example 4) Except that the metal foil 1 is replaced with the metal foil 3, a laminate 4 having a F layer thickness of 12 μm is manufactured in the same manner as in Example 1. Two laminates 4 and one polyimide film (thickness: 25 μm; manufactured by Ube Industries, Ltd., "Upilex 25S") are used, and both sides of the polyimide film are pressed against the F layer of each laminate 1 and heated at 360°C for lamination, thereby manufacturing a laminate 41 having metal foil layers on the outermost surfaces of both sides.

(Example 5 (Comparative Example)) Except that metal foil 3 was replaced by metal foil 4, laminate 5 and laminate 51 with a thickness of 12 μm of F layer were manufactured in the same manner as in Example 4. (Example 6 (Comparative Example)) Except that metal foil 3 was replaced by metal foil 5, laminate 6 and laminate 61 with a thickness of 12 μm of F layer were manufactured in the same manner as in Example 4. (Example 7 (Comparative Example)) Except that dispersion 1 was replaced by dispersion 3, laminate 7 with a thickness of 12 μm of F layer was manufactured in the same manner as in Example 4.

(Example 8) First, the dispersion 4 is applied to the surface of the metal foil 7 by the gravure reverse method in a roll-to-roll manner to form a liquid coating. Then, the metal foil 7 formed with the liquid coating is dried by passing through a drying furnace at 100°C, 120°C and 140°C for a total of 5 minutes. Thereafter, the dried coating is heated at 380°C for 3 minutes in a far infrared oven under a nitrogen environment. In this way, a laminate 8 having an F layer formed on the surface of the metal foil layer is manufactured. In addition, the thickness of the F layer is 5 μm. Next, the F layer side of the laminate 8 is subjected to vacuum plasma treatment, and then the F layer of the laminate 8 is laminated with the prepreg 1 and hot-pressed at a temperature of 200°C, a pressure of 3 MPa, and a time of 15 minutes. Next, the entire metal foil layer of the laminate 8 is removed by an acid solution, and in this state, the prepreg 1 is directly laminated on the contact surface (exposed surface) and hot-pressed at a temperature of 200°C, a pressure of 3 MPa, and a time of 15 minutes. In this way, a composite laminate 8 is obtained in which the exposed F layer and the prepreg are laminated.

(Example 9) Composite laminate 9 was produced in the same manner as in Example 8 except that metal foil 7 was replaced by metal foil 6 and dispersion 4 was replaced by dispersion 5. (Example 10) Composite laminate 10 was produced in the same manner as in Example 8 except that dispersion 4 was replaced by dispersion 5. (Example 11 (Comparative Example)) Composite laminate 11 was produced in the same manner as in Example 10 except that metal foil 7 was replaced by metal foil 8 and the thickness of the F layer was set to 15 μm.

(Example 12) First, the sheet 1 is laminated on the surface of the metal foil 7 and hot-pressed for 3 minutes at 380°C in an oven under a nitrogen atmosphere. Thus, a laminate having an F layer formed on the surface of the metal foil layer is manufactured. Then, the F layer side of the laminate is subjected to vacuum plasma treatment, and then the F layer of the laminate is laminated with the prepreg 1 and hot-pressed at a temperature of 200°C, a pressure of 3 MPa, and a time of 15 minutes. Next, the entire metal foil layer of the laminate is removed by using an acid solution, and in this state, the prepreg 1 is directly laminated on the contact surface (exposed surface) thereof, and hot pressing bonding is performed at a temperature of 200°C, a pressure of 3 MPa, and a time of 15 minutes. In this way, a composite laminate 12 is obtained in which the exposed F layer and the prepreg are laminated. (Example 13) Composite laminate 13 is manufactured in the same manner as Example 12 except that sheet 1 is replaced with sheet 2.

5. Evaluation of laminates 5-1. Peel strength between metal foil layer and F layer of laminates (Part 1) The laminates of Examples 1 to 3 were cut into rectangular shapes (length 100 mm, width 10 mm) to prepare 50 samples. Then, each sample was fixed at a position 50 mm away from one end in the length direction, and the metal foil layer and F layer were peeled from one end in the length direction at a tensile speed of 50 mm/min at 90°, and the maximum load (N/cm) applied at this time was measured. The results are shown in Summary Table 1.

[Table 1] The number of the layer 1 2 3 F polymer F polymer 1 F polymer 1 F polymer 2 Metal Foil Metal Foil 1 Metal Foil 2 Metal Foil 1 Peel strength [N/cm] Average ± Deviation 16±0.5 8±4 3±0.5

In laminate 1, since the surface of the metal foil was not treated with a silane coupling agent, a higher peeling strength was obtained, and the variation of the peeling strength between samples was small. In contrast, in laminate 2, since the surface of the metal foil was overtreated with a silane coupling agent, not only was it not possible to obtain a sufficient peeling strength, but the variation of the peeling strength between samples was also large. In addition, in laminate 3, since F polymer 2 without an oxygen-containing polar group was used, a metal foil whose surface was not treated with a silane coupling agent was used, resulting in a lower peeling strength.

5-2. Peel strength between metal foil layer and F layer of laminate (Part 2) 5-2-1. Initial peel strength between metal foil layer and F layer of laminate Two laminates 4 were stacked with their F layers in contact with each other and vacuum-pressed at 340°C for 20 minutes to obtain a sample. For this sample, the metal foil layer etched to a width of 3.2 mm was peeled at an angle of 90° according to IPC-TM650-2.4.9.E MethodA, and its peel strength was measured. For each of the laminates 5 to 7, the peel strength of the sample prepared in the same manner as the laminate 4 was also measured. 5-2-2. Peel strength after heating between the metal foil layer and the F layer of the laminate Each sample prepared in 5-2-1 was placed in an oven at 150°C for heating, and after 1000 hours, the peel strength was measured using the same method as 5-2-1. In addition, the retention rate (%) was calculated according to the following calculation formula. Retention rate (%) = (peel strength after heating) / (initial peel strength) × 100 The results are summarized in Table 2.

[Table 2] The number of the layer 4 5 6 7 Metal Foil Metal Foil 3 Metal Foil 4 Metal Foil 5 Metal Foil 3 Ratio of nickel atoms [mass %] 0.06 0.00 0.30 0.06 F polymer F polymer 1 F polymer 1 F polymer 1 F polymer 2 Peel strength [N/cm] Early days 12 9 15 4 After heating 10 6 11 - Retention rate [%] 83 67 73 -

5-3. Measurement of transmission loss A sample circuit of a microstrip line was formed using the multilayer body 41. The line width of the signal layer was set to 120 μm, the line length was set to 50 mm, and the back side was set to a full ground layer. The sample circuit was clamped using a UTF (Universal Test Fixture) and the transmission loss at 40 GHz was measured using a network analyzer. The transmission loss of each of the multilayer body 51 and the multilayer body 61 was also measured in the same manner as the multilayer body 41. The results are shown in Summary Table 3.

[Table 3] The number of the layer 41 51 61 Metal Foil Metal Foil 3 Metal Foil 4 Metal Foil 5 Ratio of nickel atoms [mass %] 0.06 0.00 0.30 F polymer F polymer 1 F polymer 1 F polymer 1 Transmission loss (40 GHz) -2.4 -2.1 -3.0

5-4. Peel strength between prepreg layer and F layer of composite laminate (Part 3) Cut composite laminate 8 into a rectangular shape (length 100 mm, width 10 mm) to prepare a sample. Then, fix the sample 50 mm away from one end in the length direction, and peel the prepreg layer and F layer from one end in the length direction at a tensile speed of 50 mm/min at 90°, and measure the maximum load (N/cm) applied at this time. For each of composite laminates 9 to 13, the peel strength of the sample prepared in the same manner as composite laminate 8 was also measured and evaluated according to the following criteria. [Evaluation criteria] ◎: 15 N/cm or more ○: 10 N/cm or more but less than 15 N/cm △: 5 N/cm or more but less than 10 N/cm ×: less than 5 N/cm The results are shown in Summary Table 4.

[Table 4] Composite layer number 8 9 10 11 12 13 Metal Foil Metal Foil7 Metal Foil 6 Metal Foil7 Metal Foil8 Metal Foil7 Metal Foil7 Ten-point surface roughness [μm] 1.2 0.2 1.2 7.7 1.2 1.2 Dispersion Dispersion 4 Dispersion 5 Dispersion 5 Dispersion 5 - - Sheet - - - - Sheet 1 Sheet 2 Peel strength ◎ △ ○ × ○ △

6. Manufacturing of a composite laminate with a solder resist layer (Example 14) Layer F of laminate 8 and prepreg 1 are laminated and heat-pressed in the same manner as in Example 8. Then, the entire metal foil layer is removed using an acid solution, and the contact surface (exposed surface) is treated with a soft etching agent ("Glibrite GB-4300" manufactured by Shikoku Chemical Industries, Ltd.). The soft etching agent is an aqueous solution containing sulfuric acid and hydrogen peroxide. Thereafter, a solder resist ("PSR-4000 LD1K" manufactured by TAIYO INK Co., Ltd.) was directly applied to the exposed surface after treatment by screen printing to a thickness of 30 μm in this state (without polishing).

Next, the solder resist was dried at 80°C for 3 minutes and exposed to 400 mJ/ ^cm2 UV (ultraviolet) light, and then immersed in a 1 mass % sodium carbonate aqueous solution for 60 seconds for development. Thereafter, the solder resist was post-cured at 150°C for 60 minutes and further exposed to 1000 mJ/ ^cm2 UV light to form a solder resist layer, obtaining a composite laminate 14 formed by laminating the exposed F layer and the solder resist layer.

(Example 15) A composite laminate 15 is obtained in the same manner as in Example 14 except that the metal foil 8 is used. (Example 16) A composite laminate 16 is obtained in the same manner as in Example 14 except that the contact surface (exposed surface) of the F layer is treated with a soft etching agent and polished and then coated with a solder resist.

7. Evaluation of Adhesion For each of the laminates 14 to 16, the adhesion between the F layer and the solder mask layer was evaluated using the 100-grid cross-cut test specified in K5600-5-6:1999 (ISO 2409:1992). The result showed that the cut edge of the composite laminate 14 was completely smooth, and no peeling occurred in any mesh of the grid. The composite laminate 15 peeled off significantly along the cut edge. For the composite laminate 16, partial peeling was confirmed along the cut edge and at the intersection of the cut. [Industrial Applicability]

The multilayer body of the present invention and the composite multilayer body produced by the present invention have excellent electrical properties and adhesion and have a polymer layer firmly fixed to the metal foil layer, so they can be processed into antenna parts, printed wiring boards, insulation layers of power semiconductors, aircraft parts, automobile parts, etc.

Claims (11)

A laminate having a metal foil layer and a polymer layer, wherein the laminate has a metal foil layer and a polymer layer, wherein the polymer layer is directly disposed on the surface of the metal foil layer and comprises a tetrafluoroethylene polymer having a melt viscosity of 1×10 ² to 1×10 ⁶ Pa‧s at 380°C; wherein the metal foil layer has no silicon atoms on the surface and the ratio of nickel atoms detected by fluorescent X-ray analysis of the surface is 0.03 to 0.25 mass %. The metal foil layer has a base layer and a roughening treatment layer comprising metal particles and having the surface, wherein the metal particles comprise needle-shaped metal particles, and the ten-point average roughness of the surface of the metal foil layer is 0.3 to 1.3 μm. A laminate having a metal foil layer and a polymer layer as in claim 1, wherein the metal particles are formed of copper, nickel, phosphorus, tungsten, arsenic, molybdenum, chromium, cobalt, zinc or an alloy containing one or more of these. A laminate having a metal foil layer and a polymer layer as claimed in claim 1 or 2, wherein the tetrafluoroethylene polymer is a tetrafluoroethylene polymer containing units based on perfluoro(alkyl vinyl ether), or polytetrafluoroethylene having a number average molecular weight of 200,000 or less. A laminate having a metal foil layer and a polymer layer as claimed in claim 1 or 2, wherein the tetrafluoroethylene polymer is a tetrafluoroethylene polymer containing units based on perfluoro(alkyl vinyl ether) and having oxygen-containing polar groups, or a tetrafluoroethylene polymer containing 2.0-5.0 mol% of units based on perfluoro(alkyl vinyl ether) relative to all units and having no oxygen-containing polar groups. A laminate having a metal foil layer and a polymer layer as in claim 1 or 2, wherein the peeling strength of the polymer layer with respect to the metal foil layer is greater than 10N/cm. A method for manufacturing a laminated body comprises forming a silane coupling agent having a melt viscosity of 1×10 ² to 1×10 ⁶ at 380°C in direct contact with the surface of the metal foil without treating the surface of the metal foil with a silane coupling agent. A polymer layer of a tetrafluoroethylene polymer with a molecular weight of 0.05 Pa‧s is prepared to obtain a laminate having the polymer layer directly contacting the surface of a metal foil layer including the metal foil, wherein the metal foil layer has no silicon atoms on the surface and the ratio of nickel atoms detected by fluorescent X-ray analysis of the surface is 0.03-0.25 mass %, the metal foil layer has a substrate layer, and a roughening layer including metal particles and having the surface, the metal particles include needle-shaped metal particles, and the ten-point average roughness of the surface of the metal foil layer is 0.3-1.3 μm. A method for manufacturing a composite laminate comprises: a metal foil layer having a surface with a ten-point average roughness of 0.3-1.3 μm, and a metal foil layer having a melt viscosity of 1×10 ² -1×10 ⁶ at 380°C disposed on the surface. At least a portion of the metal foil layer of the laminate of the polymer layer of the tetrafluoroethylene polymer of Pa‧s is removed, and the exposed polymer layer is bonded to the prepreg, so as to obtain a composite laminate having at least the polymer layer and the prepreg layer, wherein the metal foil layer has no silicon atoms on the surface and the ratio of nickel atoms detected by fluorescent X-ray analysis of the surface is 0.03-0.25 mass %, and the metal foil layer has a base material layer and a roughening layer containing metal particles and having the surface, and the metal particles include needle-shaped metal particles. The manufacturing method of claim 7 is to bond the surface of the exposed polymer layer to the prepreg without subjecting the surface to hydrophilization treatment. A method for manufacturing a composite laminate comprises: a metal foil layer having a surface with a ten-point average roughness of 0.3-1.3 μm, and a metal foil layer having a melt viscosity of 1×10 ² -1×10 ⁶ at 380°C disposed on the surface. At least a portion of the metal foil layer of the laminate of the polymer layer of the tetrafluoroethylene polymer of Pa‧s is removed, and a solder resist is applied on the exposed polymer layer to harden it to form a solder resist layer, thereby obtaining a composite laminate having at least the polymer layer and the solder resist layer, wherein the metal foil layer has no silicon atoms on the surface and the ratio of nickel atoms detected by fluorescent X-ray analysis of the surface is 0.03-0.25 mass %, and the metal foil layer has a base layer and a roughening layer containing metal particles and having the surface, and the metal particles include needle-shaped metal particles. As in the manufacturing method of claim 9, the surface of the exposed polymer layer is treated with an acid solution, and a solder resist is directly applied in this state to harden it to form a solder resist layer. A method for manufacturing a polymer film comprises removing a metal foil layer having a surface with a ten-point average roughness of 0.3-1.3 μm and a polymer layer disposed on the surface and comprising a tetrafluoroethylene polymer having a melt viscosity of 1×10 ² -1×10 ⁶ Pa‧s at 380°C, and using the remaining polymer layer as a polymer film, wherein the metal foil layer has no silicon atoms on the surface and the ratio of nickel atoms detected by fluorescent X-ray analysis of the surface is 0.03-0.25 mass %, and the metal foil layer has a substrate layer and a roughening layer comprising metal particles and having the surface, wherein the metal particles include needle-shaped metal particles.