CN113365804A

CN113365804A - Laminate and method for producing same, method for producing composite laminate, and method for producing polymer film

Info

Publication number: CN113365804A
Application number: CN202080011655.2A
Authority: CN
Inventors: 笠井涉; 山边敦美; 寺田达也; 细田朋也
Original assignee: Asahi Glass Co Ltd
Current assignee: AGC Inc
Priority date: 2019-01-30
Filing date: 2020-01-24
Publication date: 2021-09-07
Also published as: KR20210121048A; JP7230932B2; TW202037488A; JPWO2020158604A1; WO2020158604A1

Abstract

The invention provides a laminate which can obtain uniform and high adhesiveness between a polymer layer and a metal foil layer, and a manufacturing method thereof. The laminate of the present invention is a laminate having a metal foil layer and a polymer layer provided in direct contact on a surface of the metal foil layer, the polymer layer containing a melt viscosity at 380 ℃ of 1 × 10²～1×10⁶And Pa s, wherein the metal foil layer is a metal foil layer having no silicon atom on the surface, or a metal foil layer having a nickel atom content of 0.03 to 0.25 mass% detected by fluorescent X-ray analysis of the surface.

Description

Laminate and method for producing same, method for producing composite laminate, and method for producing polymer film

Technical Field

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

Background

In order to reduce the dielectric constant of a printed wiring board, there are cases where the surface roughness of a copper foil is reduced or a polymer layer is formed using a low dielectric constant polymer. However, low dielectric constant polymers are generally less polar and have poor adhesion to other materials. Further, since the surface smoothness of the copper foil with reduced surface roughness is too high, the anchoring effect of the polymer layer is hardly generated, and the adhesiveness is poor. Therefore, it is difficult to achieve strong adhesion between the polymer layer containing the low dielectric constant polymer and 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 a silicon atom such as a silane coupling agent. It is needless to say that the surface of the copper foil used for the commercial printed wiring board is treated with a silane coupling agent.

In recent years, tetrafluoroethylene polymers (TFE polymers) have attracted attention as low dielectric constant polymers, but TFE polymers have particularly poor adhesion to other materials. Therefore, the surface of the copper foil is treated with a silane coupling agent to improve the adhesion to the copper foil (see patent document 1).

In addition, as the wiring in the printed wiring board is becoming finer, there is a printed wiring board in which the pitch between wirings is 30 μm or less. When the pitch is reached, copper ions are easily eluted from the copper foil to cause a short circuit (migration) between the wirings. In order to prevent elution of copper ions due to oxidation of copper, a metal layer such as nickel, cobalt, or zinc may be provided as a barrier layer between the copper foil and the polymer layer (insulating layer) (see patent documents 2 and 3).

Nickel is excellent as a barrier layer, but since it has a higher resistivity than copper, transmission loss of a printed wiring board containing a large amount of nickel becomes large. In addition, since nickel itself is easily denatured at high temperature, the adhesiveness between the polymer layer and the copper foil is easily lowered after high-temperature exposure in the process of manufacturing a printed wiring board.

In order to solve the above problem, it has been proposed to provide an oxidation-resistant treated layer containing cobalt and molybdenum on the surface of a copper foil (see patent document 4).

Further, in the production of a printed wiring board, a copper foil with a TFE-based polymer layer copper foil is processed into a circuit pattern, and then the TFE-based polymer layer is bonded to a prepreg so as to cover the entire circuit pattern, and the laminate is sometimes produced. In this case, the adhesion between the TFE-based polymer layer and the prepreg is low, and delamination tends to occur between these layers. Therefore, before the prepreg is bonded, the surface of the TFE-based polymer layer is subjected to a surface treatment (silane coupling agent treatment, plasma treatment, etc.) to improve the adhesiveness (see patent documents 5 and 6).

Documents of the prior art

Patent document

Patent document 1: international laid-open publication No. 2014/192718

Patent document 2: japanese patent laid-open No. 2008-118163

Patent document 3: japanese patent laid-open No. 2008-132757

Patent document 4: japanese patent laid-open publication No. 2017-141489

Patent document 5: japanese patent laid-open No. 2018-011033

Patent document 6: international publication No. 2018/212285

Disclosure of Invention

Technical problem to be solved by the invention

However, according to the studies of the present inventors, since the interaction between the TFE-based polymer and the silane coupling agent is also poor, the effect of improving the adhesion between the TFE-based polymer and the copper foil by the silane coupling agent is limited. In addition, the reactivity of the silane coupling agent and the amount of adhesion thereof to the surface of the copper foil tend to vary, which is an unstable factor in the adhesion between the TFE-based polymer and the copper foil. The present inventors have found that when a predetermined TFE-based polymer and a predetermined metal foil are used, unstable factors caused by a silane coupling agent can be eliminated.

Further, according to the studies of the present inventors, in the case of using a TFE-based polymer as a low dielectric constant polymer, the initial adhesion between the layer containing cobalt or molybdenum and the TFE-based polymer is very low, and the adhesion after high-temperature exposure is not sufficient. Accordingly, the present inventors have earnestly studied to improve the initial adhesion, and as a result, they have found that a laminate excellent in both the initial adhesion and the adhesion after high-temperature exposure and also excellent in electrical characteristics can be obtained by using a metal foil having a surface on which nickel is present in a predetermined trace amount range and providing a polymer layer containing a predetermined TFE-based polymer on the surface of the metal foil.

Further, the present inventors have found that when a metal foil having a predetermined surface property is used, a polymer layer containing a TFE-based polymer exhibiting high adhesion to a prepreg can be obtained, and have completed the present invention.

That is, an object of the present invention is to provide a laminate capable of obtaining uniform and high adhesion between a polymer layer and a metal foil layer, and a method for producing the same.

It is another object of the present invention to provide a laminate having high initial adhesion between a polymer layer and a metal foil layer, maintaining high adhesion even after a high-temperature thermal process, and having excellent electrical characteristics, and a method for manufacturing the same.

It is another object of the present invention to provide a method for producing a polymer film which exhibits high adhesion to a prepreg or the like even if surface treatment is omitted, and a method for producing a composite laminate in which peeling between a polymer layer and a prepreg layer is less likely to occur.

Technical scheme for solving technical problem

The present invention has the following technical contents.

< 1 > a laminate having a metal foil layer and a polymer layer provided in direct contact with a surface of the metal foil layer, the polymer layer comprising a melt viscosity at 380 ℃ of 1 x 10²～1×10⁶And Pa s, wherein the metal foil layer is a metal foil layer having no silicon atom on the surface, or a metal foil layer having a nickel atom content of 0.03 to 0.25 mass% detected by fluorescent X-ray analysis of the surface.

The laminate of < 2 > or < 1 > wherein the metal foil layer comprises a base material layer and a roughened layer comprising metal particles and having the surface.

The laminate of < 3 > such as < 1 > or < 2 >, wherein the metal foil layer comprises a base material layer and a roughened layer having the surface and comprising metal particles made of copper, nickel, phosphorus, tungsten, arsenic, molybdenum, chromium, cobalt, zinc, or an alloy containing 1 or more of these.

The laminate of < 4 > such as < 1 > - < 3 >, wherein the metal foil layer comprises a substrate layer and a roughened layer having the surface and comprising metal particles, and the metal particles comprise acicular metal particles.

The laminate according to any one of < 5 > to < 1 > < 4 >, wherein the ten-point average roughness of the surface of the metal foil layer is 0.1 μm or more.

[ claim 6 ] the laminate according to any one of [ 1 ] to [ 5], wherein the tetrafluoroethylene polymer is a tetrafluoroethylene polymer containing a perfluoro (alkyl vinyl ether) -based unit, or polytetrafluoroethylene having a number average molecular weight of 20 ten thousand or less.

[ 7] the laminate according to any one of [ 1 ] to [ 6 ], wherein the tetrafluoroethylene polymer is a tetrafluoroethylene polymer having an oxygen-containing polar group and containing a perfluoro (alkyl vinyl ether) -based unit, or a tetrafluoroethylene polymer having no oxygen-containing polar group and containing a perfluoro (alkyl vinyl ether) -based unit in an amount of 2.0 to 5.0 mol% based on the total units.

The laminate of any one of < 8 > to < 1 > < 7 >, wherein the polymer layer has a peel strength of 10N/cm or more with respect to the metal foil layer.

< 9 > a method for producing a laminate, which comprises forming a polymer layer on a surface of a metal foil in direct contact therewith without treating the surface of the metal foil with a silane coupling agent, and obtaining a laminate having the polymer layer provided in direct contact with a surface of a metal foil layer comprising the metal foil, wherein the polymer layer has a melt viscosity of 1 x 10 at 380 ℃²～1×10⁶Pa·s a tetrafluoroethylene polymer.

< 10 > a method for producing a laminate, which comprises forming a polymer layer in direct contact with the surface of a metal foil having a nickel atom content of 0.03 to 0.25 mass% detected in a fluorescent X-ray analysis, and obtaining a laminate having the polymer layer provided in direct contact with the surface of a metal foil layer comprising the metal foil, wherein the polymer layer comprises a polymer having a melt viscosity of 1X 10 at 380 ℃ and a melt viscosity of 1X 10²～1×10⁶Pa · s tetrafluoroethylene polymer.

< 11 > a method for producing a composite laminate, which comprises removing at least a part of a metal foil layer of a laminate comprising a metal foil layer having a surface with a ten-point average roughness of 0.1 μm or more and a polymer layer provided on the surface, and bonding the exposed polymer layer to a prepreg to obtain a composite laminate comprising at least the polymer layer and the prepreg layer laminated together, wherein the polymer layer comprises a polymer having a melt viscosity of 1 x 10 at 380 ℃ and²～1×10⁶pa · s tetrafluoroethylene polymer.

< 12 > the production method of < 11 > wherein the exposed surface of the polymer layer is bonded to the prepreg without subjecting it to hydrophilization treatment.

< 13 > a method for producing a composite laminate, which comprises removing at least a part of a metal foil layer of a laminate comprising a metal foil layer having a surface with a ten-point average roughness of 0.1 μm or more and a polymer layer provided on the surface, coating a solder resist on the exposed polymer layer, and curing the coating to form a solder mask layer, thereby obtaining a composite laminate in which at least the polymer layer and the solder mask layer are laminated, wherein the polymer layer comprises a polymer having a melt viscosity of 1 x 10 at 380 ℃ and²～1×10⁶pa · s tetrafluoroethylene polymer.

< 14 > such as < 13 > wherein the surface of the exposed polymer layer is treated with an acid solution, and thus a solder resist is directly applied and cured to form a solder mask layer.

< 15 > A method for producing a polymer filmA method of removing a metal foil layer of a laminate having the metal foil layer having a surface with a ten-point average roughness of 0.1 [ mu ] m or more and a polymer layer provided on the surface, the polymer layer remaining as a polymer film, the polymer layer containing a polymer having a melt viscosity of 1 x 10 at 380 ℃²～1×10⁶Pa · s tetrafluoroethylene polymer.

Effects of the invention

According to the present invention, a laminate capable of obtaining uniform and high adhesion between a polymer layer and a metal foil, and a method for producing the same can be provided.

Further, according to the present invention, a laminate having high initial adhesion between a polymer layer and a metal foil, maintaining high adhesion even after a high-temperature thermal process, and excellent electrical characteristics, and a method for manufacturing the same can be provided.

According to the present invention, a polymer film exhibiting high adhesion to a prepreg or the like and a composite laminate in which peeling between a polymer layer and a prepreg layer is less likely to occur can be provided.

Detailed Description

The following terms have the following meanings.

"D50 of the powder" means a particle size distribution of the powder measured by a laser diffraction scattering method, and a cumulative curve obtained by taking the total volume of a group of particles constituting the powder (hereinafter also referred to as "powder particles") as 100%, and a particle diameter at a point on the cumulative curve where the cumulative volume reaches 50% (volume-based cumulative 50% diameter).

"D90 of the powder" means a particle size (cumulative 90% diameter on a volume basis) of a point on a cumulative curve where the cumulative volume reaches 90% by measuring the particle size distribution of the powder by a laser diffraction scattering method and determining the cumulative curve with the total volume of the powder particle group as 100%.

That is, D50 and D90 of the powder are the volume-based cumulative 50% diameter and the volume-based cumulative 90% diameter of the powder particles, respectively.

"melt viscosity of polymer" means a value measured by holding a polymer sample (2g) heated to a measurement temperature in advance for 5 minutes at the measurement temperature under a load of 0.7MPa using a flow tester and a 2. phi. -8L mold based on ASTM D1238.

The "melting temperature (melting point) of a polymer" means a temperature corresponding to the maximum value of the melting peak of the polymer measured by a Differential Scanning Calorimetry (DSC) method.

"viscosity" means a value measured at room temperature (25 ℃) at 30rpm using a B-type viscometer. The measurement was repeated 3 times, and the average of the 3 measurements was taken.

"ten-point average roughness (Rzjis)" is JIS B0601: 2013, attached JA.

The "peel strength" is the maximum load (N/cm) applied when the metal foil and the polymer layer are peeled from the laminate at 90 ° from the other end in the longitudinal direction at a stretching speed of 50 mm/min by fixing the laminate at a position 50mm away from one end in the longitudinal direction of the laminate cut into a rectangular shape (length 100mm, width 10 mm).

The "unit" in the polymer may be a radical formed directly from a monomer by polymerization, or a radical obtained by treating a polymer obtained by polymerization by a predetermined method to convert a part of the structure. The unit based on the monomer a contained in the polymer is also referred to simply as "monomer a unit".

The laminate (the present laminate) of the present invention has 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, the polymer layer containing a polymer having a melt viscosity of 1 × 10 at 380 ℃²～1×10⁶And a tetrafluoroethylene polymer of Pa · s (hereinafter also referred to as "F polymer").

The metal foil layer in the 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 content of 0.03 to 0.25 mass% detected by fluorescent X-ray analysis of the surface (hereinafter also referred to as "metal foil layer 2").

Hereinafter, the present laminate having the metal foil layer 1 is also referred to as the present laminate 1, and the present laminate having the metal foil layer 2 is also referred to as the present laminate 2.

The 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. In addition, the F layer may be provided on only one surface of the metal foil layer 1, or may be provided on both surfaces thereof.

In the present laminate 1, no silicon atom is present on the surface (surface on the F layer side) of the metal foil layer 1. This means that the surface of the metal foil layer 1 is not treated with a silane coupling agent. That is, the method for producing the laminate 1 is a method for forming an F layer on the surface of the metal foil layer 1 in direct contact without treating the surface with a silane coupling agent.

Whether or not silicon atoms are present on the surface of the metal foil layer 1 can be confirmed by analyzing the surface of the metal foil layer 1 by fluorescent X-ray analysis (XRF). The amount of silicon atoms detected by this analysis may be equal to or less than the detection limit.

It is considered that oxides (hydroxides, etc.) generated by oxidation exist on the surface of the metal foil constituting the metal foil layer 1. On the other hand, it is considered that the F polymer having a predetermined melt viscosity is likely to interact with oxides and/or metal atoms present on the surface of the metal foil, and particularly if the F polymer contains an oxygen-containing polar group, the oxygen-containing polar group strongly interacts with the oxides and/or metal atoms present on the surface of the metal foil. As a result, the laminate 1 was estimated to exhibit high adhesiveness between the F layer containing the F polymer and the metal foil.

In addition, the treatment with the silane coupling agent is performed by wet spreading on the surface of the metal foil with a solution containing the silane coupling agent. Therefore, it is considered that, in the initial stage, the solution is more likely to concentrate on the portion where the silane coupling agent is bonded, the portion where the silane coupling agent is bonded and the portion where the silane coupling agent is not bonded are scattered in island shapes, and the amount of the silane coupling agent present on the surface of the metal foil is not uniform. Further, the degree of this is greatly influenced by the surface properties of the metal foil. Therefore, when the F layer is formed on the surface of the metal foil in the above state, it is difficult to exhibit uniform adhesion between the F layer and the metal foil. In contrast, in the present laminate 1, since the surface of the metal foil is not treated with a silane coupling agent, it is presumed that the above-described adverse factors can be prevented from occurring, and therefore uniform adhesion between the F layer and the metal foil (metal foil layer 1) can be obtained.

The 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. In addition, the F layer may be provided on only one surface of the metal foil layer 2, or may be provided on both surfaces thereof.

In the laminate 2, nickel atoms are present in a predetermined amount (trace amount) on the surface (surface on the F layer side) of the metal foil layer 2. The method for producing the laminate 2 is a method for forming an F layer on the surface of a metal foil in which a predetermined amount of nickel atoms are present in direct contact with each other.

In addition, the proportion of nickel atoms present on the surface of the metal foil can be measured by analyzing the surface of the metal foil by fluorescent X-ray analysis (XRF).

It is considered that nickel oxide (hydroxide, etc.) generated by oxidation exists on the surface of the metal foil constituting the metal foil layer 2. On the other hand, it is considered that the F polymer having a predetermined melt viscosity is likely to strongly interact with the oxide or nickel atom present on the surface of the metal foil, and particularly if the F polymer contains an oxygen-containing polar group, the oxygen-containing polar group strongly interacts with the oxide or nickel atom. As a result, the laminate 2 was estimated to exhibit high initial adhesion between the F layer containing the F polymer and the metal foil (metal foil layer 2).

Further, it is considered that the effect of preventing the deterioration (corrosion) of the surface of the metal foil due to the F polymer is exerted by the presence of the nickel atom. Therefore, it is presumed that the laminate 2 maintains high adhesion between the F layer and the metal foil (metal foil layer 2) even after undergoing a thermal process at high temperature.

The F polymer of the present invention is a polymer containing Tetrafluoroethylene (TFE) based units (TFE units), and is preferably a hot-melt processable polymer.

The melt viscosity of the F polymer at 380 ℃ is 1X 10²～1×10⁶Pa · s, preferably 1X 10³～1×10⁶Pa·s。

The melting temperature of the F polymer is preferably 140 to 320 ℃, more preferably 200 to 320 ℃, and further preferably 260 to 320 ℃. In this case, the adhesiveness of the F layer to the metal foil (metal foil layers 1 and 2) is likely to be further improved.

The F polymer preferably has oxygen-containing polar groups.

The oxygen-containing polar group of the F polymer may be contained in a unit based on a monomer having an oxygen-containing polar group, may be contained in a terminal portion of a polymer main chain, may be contained in the polymer by surface treatment (radiation treatment, electron beam treatment, corona treatment, plasma treatment, or the like), and is preferably the first. The oxygen-containing polar group of the F polymer may be a group obtained by modifying a polymer having a group capable of forming an oxygen-containing polar group. The oxygen-containing polar group contained in the polymer terminal group can be obtained by adjusting components (a polymerization initiator, a chain transfer agent, and the like) used in polymerization of the polymer.

The oxygen-containing polar group is a polar atomic group containing an oxygen atom. However, the oxygen-containing polar group of the present invention does not include an ester bond itself and an ether bond itself, but includes an atomic group contained by these bonds as characteristic groups.

The oxygen-containing polar group is preferably at least 1 group selected from the group consisting of a hydroxyl-containing group, a carbonyl-containing group, an acetal group and an oxirane group, more preferably a hydroxyl-containing group or a carbonyl-containing group, and still more preferably-CF₂CH₂OH、-C(CF₃)₂OH, 1, 2-diol group (-CH (OH) CH₂OH)、-CF₂C (O) OH, > CFC (O) OH, carboxamide (-C (O) NH)₂Etc.), 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 a carbonate group (-OC (O) O-).

In addition, the oxygen-containing polar group is a cyclic group or a ring-opening group thereof as a polar group, and a cyclic acid anhydride residue, a cyclic imide residue, a cyclic carbonate group, a cyclic acetal group, a 1, 2-dicarboxylic acid residue, or a 1, 2-diol group is particularly preferable, and a cyclic acid anhydride residue is most preferable, from the viewpoint of not impairing the adhesion of the F layer to the metal foil.

The oxyalkylene group is preferably an epoxy group or an oxetane group.

The F polymer is preferably a polymer comprising TFE units, and units based on Hexafluoropropylene (HFP) or perfluoro (alkyl vinyl ether) (PAVE) or fluoroalkyl ethylene (FAE) (hereinafter also referred to as "PAE units"), and units based on monomers having an oxygen-containing polar group (hereinafter also referred to as "polar units").

The proportion of the TFE unit in the total units constituting the F polymer is preferably 50 to 99 mol%, and particularly preferably 90 to 99 mol%.

PAE units are preferably PAVE-based units or HFP-based units, particularly preferably PAVE-based units. The number of PAE units may be 2 or more.

As PAVE, CF is mentioned₂＝CFOCF₃(PMVE)、CF₂＝CFOCF₂CF₃、CF₂＝CFOCF₂CF₂CF₃(PPVE)、CF₂＝CFOCF₂CF₂CF₂CF₃、CF₂＝CFO(CF₂)₈F, preferably PMVE or PPVE.

As FAE, CH may be mentioned₂＝CH(CF₂)₂F(PFEE)、CH₂＝CH(CF₂)₃F、CH₂＝CH(CF₂)₄F(PFBE)、CH₂＝CF(CF₂)₃H、CH₂＝CF(CF₂)₄H, preferably PFEE or PFBE.

The proportion of the PAE unit in the total units constituting the F polymer is preferably 0.5 to 9.97 mol%, more preferably 0.5 to 9.97 mol%.

The polar unit is preferably a unit based on a monomer having an acid 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 acid anhydride residue or a cyclic carbonate group, and still more preferably a monomer unit having a cyclic acid anhydride residue. The number of the polar units may be 1 or 2 or more.

The monomer having a cyclic acid anhydride residue is preferably itaconic anhydride, citraconic anhydride, 5-norbornene-2, 3-dicarboxylic anhydride (alias: nadic anhydride; hereinafter also referred to as "NAH") or maleic anhydride, and more preferably NAH.

The proportion of the polar unit in the total units constituting the F polymer is preferably 0.01 to 3 mol%.

In addition, the F polymer in this case may further contain a unit (hereinafter also referred to as "other unit") other than the TFE unit, the PAE unit, and the polar unit. The number of other units may be 1 or 2 or more.

Examples of the monomer forming the other unit include ethylene, propylene, vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride (VDF), and Chlorotrifluoroethylene (CTFE). The other unit is preferably ethylene, VDF or CTFE, more preferably ethylene.

The proportion of the other units in the F polymer in the total units constituting the F polymer is preferably 0 to 50 mol%, more preferably 0 to 40 mol%.

Suitable forms of the F polymer include an F polymer containing a PAVE-based unit (PAVE unit), and PTFE having a number average molecular weight of 20 ten thousand or less.

The number average molecular weight of the PTFE is a value calculated based on the following formula (1).

Mn＝2.1×10¹⁰×ΔHc^-5.16···(1)

In the formula (1), Mn represents the number average molecular weight of the PTFE, and Δ Hc represents the heat of crystallization (cal/g) of the PTFE as measured by differential scanning calorimetry.

The Mn of the PTFE is preferably 10 or less, more preferably 5 ten thousand or less. The Mn of the PTFE is preferably 1 ten thousand or more.

More preferable forms of the F polymer include an F polymer having an oxygen-containing polar group containing a PAVE-based unit, and an F polymer having no oxygen-containing polar group containing 2.0 to 5.0 mol% of a PAVE-based unit with respect to the whole units.

The F polymer of this form easily forms a microspherical crystal in the F layer, and easily improves adhesion to other components.

The former polymer preferably contains 90 to 99 mol% of TFE unit, 0.5 to 9.97 mol% of PAVE unit and 0.01 to 3 mol% of polar unit, respectively, with respect to the whole units.

The content of PAVE units in the latter polymer is preferably 2.1 mol% or more, more preferably 2.2 mol% relative to the total units.

The latter polymer is composed of TFE units and PAVE units only, and preferably contains 95.0 to 98.0 mol% of TFE units and 2.0 to 5.0 mol% of PAVE units relative to the whole units.

The latter polymer having no oxygen-containing polar group means that the number of carbon atoms constituting the main chain of the polymer is 1X 10⁶And the number of the oxygen-containing polar groups in the polymer is less than 500. The number of the oxygen-containing polar groups is preferably 100 or less, and more preferably 50 or less. The lower limit of the number of the above-mentioned oxygen-containing polar groups is usually 0.

The latter polymer may be produced by using a polymerization initiator or a chain transfer agent which does not generate an oxygen-containing polar group as a terminal group of a polymer chain, or may be produced by subjecting an F polymer having an oxygen-containing polar group (e.g., an F polymer having an oxygen-containing polar group derived from a polymerization initiator in a terminal group of a polymer main chain) to a fluorination treatment. As a method of the fluorination treatment, a method using a fluorine gas is exemplified (see Japanese patent laid-open publication No. 2019-194314).

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, and the like).

The metal foil is preferably a copper foil, more preferably a copper foil such as a rolled copper foil having no difference between the front and back sides and an electrolytic copper foil having a difference between the front and back sides, and further preferably a rolled copper foil. Since the rolled copper foil has a small surface roughness, the transmission loss can be reduced even when the laminate is processed into a printed wiring board. The rolled copper foil is preferably used after being immersed in a hydrocarbon organic solvent to remove rolling oil.

The surface on which the F layer is formed may be either the rolled copper foil or the electrodeposited copper foil may be either the deposition surface or the gloss surface.

The metal foil may be a carrier-attached metal foil laminated on a carrier with an intermediate layer interposed therebetween.

The metal foil may have a laminated structure including a base layer (e.g., copper foil) made of the metal and a roughening treatment layer made of metal particles (roughening particles). In this case, the surface of the roughened layer constitutes the surface of the metal foil. The roughening treatment layer may be a roughening treatment layer made of nickel-containing metal particles (roughening particles).

The metal particles are preferably formed of copper, nickel, phosphorus, tungsten, arsenic, molybdenum, chromium, cobalt, zinc, or an alloy containing 1 or more thereof, and more preferably formed of copper, nickel, cobalt, or an alloy containing 1 or more thereof.

The metal particles are further preferably formed of nickel alone or an alloy of nickel and at least 1 of copper, phosphorus, tungsten, arsenic, molybdenum, chromium, cobalt, and zinc, and most preferably an alloy of nickel and at least 1 of copper and cobalt. The metal particles have excellent adhesion to the metal (particularly copper) constituting the base material layer.

In addition, in the case of the roughened layer containing nickel, when the laminate is processed into a printed wiring board, even if wirings having a narrow width and a short spacing distance (for example, 30 μm or less) are formed from the metal foil (metal foil layers 1 and 2), the wirings can be favorably prevented from migrating to each other.

Further, the metal particles containing nickel are likely to be deposited on the base material layer so as to include the metal particles in a needle shape. If the roughening treatment layer contains needle-like metal particles, the anchoring effect of the F layer to the surface thereof is further improved, and the adhesiveness of the F layer to the metal foil is sufficiently improved.

The proportion of nickel atoms present on the surface of the metal foil (metal foil layer 2) is 0.03 to 0.25 mass%, preferably 0.04 to 0.2 mass%, and more preferably 0.05 to 0.15 mass%. When the nickel atom is present in the above range, the effect of preventing the deterioration (corrosion) of the surface of the metal foil due to the F polymer can be more effectively exerted, and the effect is small even when the nickel atom is denatured. Therefore, the adhesiveness of the F layer to the surface of the metal foil (metal foil layer 2) is less likely to decrease. Further, since the proportion of nickel atoms having a high resistivity is not excessively high, even in the case of processing the laminate into a printed wiring board, a reduction in transmission loss can be prevented.

In the metal foil having the above-described laminated structure, the roughened layer has irregularities reflecting the shape of the metal particles formed on the surface thereof. Therefore, the anchoring effect of the F layer to the surface of the metal foil (metal foil layers 1 and 2) is satisfactorily exerted, and as a result, the adhesiveness (close adhesion) of the F layer to the metal foil (metal foil layers 1 and 2) is improved. In this case, the average particle diameter of the metal particles is preferably 0.1 to 0.25. mu.m.

From the viewpoint of further improving the adhesiveness 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 (surface on the F layer side) is preferably 0.1 to 1.5 μm, and more preferably 0.3 to 1.3 μm. If the ten-point average roughness is within the above range, the degree of unevenness of the surface of the metal foil is not excessively large, and therefore, even when the laminate is processed into a printed wiring board, an increase in transmission loss can be suppressed.

The ten-point average roughness of the surface of the roughening treatment layer can be adjusted by setting the size of the metal particles, the number of the metal particles, and the like.

The roughening treatment layer is preferably formed by depositing (plating) metal particles on the base material layer by a plating method using the base material layer as a cathode. In this case, the plating amount such as the size of the metal particles and the number of the metal particles can be controlled mainly by adjusting the current density and the plating time.

The plating conditions (1) and (2) shown below are preferably used for the plating.

< plating Condition (1) >)

The liquid composition is as follows: 10-20 g/L of copper salt, 7-10 g/L of nickel salt,

Cobalt salt 7-10 g/L

Liquid temperature: 30-60 DEG C

Current density: 1 to 50A/dm²

pH value: 2.0 to 3.0

Electroplating time: 0.12 to 1.15 seconds

In addition, each 1dm²The plating amount of each metal is preferably 15 to 40mg of copper, 100 to 1500 μ g of nickel, and 700 to 2500 μ g of cobalt.

< plating Condition (2) >)

1 particle plating (1)

The liquid composition is as follows: 10-15 g/L of copper salt, 0-10 g/L of nickel salt,

0-20 g/L cobalt salt and 10-60 g/L sulfuric acid

Liquid temperature: 20-40 DEG C

Current density: 10 to 50A/dm²

Electroplating time: 0.2 to 5 seconds

1 particle plating (2)

The liquid composition is as follows: copper salt 10-30 g/L, sulfuric acid 70-120 g/L

Liquid temperature: 30 to 50 DEG C

Current density: 3 to 30A/dm²

Electroplating time: 0.2 to 5 seconds

2 times of particle plating

The liquid composition is as follows: 10-20 g/L of copper salt, 0-10 g/L of nickel salt,

0-10 g/L cobalt salt

Liquid temperature: 30-40 DEG C

Current density: 10 to 35A/dm²

Electroplating time: 0.2 to 5 seconds

The surface of the metal foil may be subjected to roughening treatment such as dry etching or wet etching to adjust the ten-point average roughness of the surface to be within the above range.

Further, depending on the combination of the F polymer and the metal constituting the metal foil, high adhesion between the F layer and the metal foil (metal foil layers 1 and 2) can sometimes be obtained even if the above roughening treatment is omitted.

Further, from the viewpoint of improving various properties, the metal foil may further include at least 1 layer of a heat-resistant treated layer, a rust-preventive treated layer, and a chromate treated layer. In the case where the metal foil is formed by lamination, these layers may be provided between the surfaces of the roughening-treated layer opposite to the base material layer or between the roughening-treated layer and the metal foil. The heat-resistant layer, the rust-preventive layer, or the chromate layer can be formed by a known method. In addition, when the heat-resistant treated layer, the rust-preventive treated layer, or the chromate treated layer constitutes the outermost layer of the metal foil, the surface thereof constitutes the surface of the metal foil.

The thickness of the metal foil is determined appropriately according to the use of the laminate, and when the laminate is processed into a printed wiring board and used, it is preferably 1 to 100 μm, more preferably 6 to 30 μm. In the case of using an extra thin metal foil and a laminated metal foil in which a support metal foil is laminated, the thickness of the extra thin metal foil is preferably 2 to 5 μm.

The method for producing the laminate comprises forming an F layer on the surface of a metal foil in direct contact without treating the surface of the metal foil with a silane coupling agent, producing the laminate 1 having the F layer provided on the surface of the metal foil layer 1 composed of the metal foil in direct contact, or forming the F layer on the surface of the metal foil in direct contact in which nickel atoms are present in a predetermined amount, producing the laminate 2 having the F layer provided on the surface of the metal foil layer 2 composed of the metal foil in direct contact. In the method for producing the laminate, the surface of the metal foil is preferably roughened as described above before the F layer is formed on the surface of the metal foil as necessary.

The F layer is preferably formed by a method in which a dispersion liquid in which powder of the F polymer is dispersed in a solvent is applied to the surface of the metal foil and then heated, or a method in which a film containing the F polymer is heat-crimped on the surface of the metal foil.

In the method of applying the dispersion to the surface of the metal foil and then heating, the present laminates 1 and 2 are obtained by applying the dispersion to the surface of the metal foil and then heating the metal foil applied with the dispersion, removing the solvent from the dispersion, and forming an F layer by firing the powder.

As a method of applying the dispersion to the surface of the metal foil, any method may be used as long as a stable liquid coating film (wet film) composed of the dispersion is formed on the surface of the metal foil, and examples thereof include a coating method, a droplet discharge method, and a dipping method, with the coating method being preferred. When the coating method is used, a liquid coating film can be efficiently formed on the surface of the metal foil with simple equipment.

Examples of the coating method include a spray method, a roll coating method, a spin coating method, a gravure coating method, a microgravure coating method, a gravure offset coating method, a blade coating method, a touch coating method (japanese: キスコート method), a bar coating method, a die coating method, a jet meyer bar coating method (japanese: ファウンテンメイヤーバー method), and a slit die coating method.

In the heating, it is preferable that the metal foil to which the dispersion is applied is held at a temperature at which the solvent volatilizes to dry the dispersion, and then the dried film is held at a temperature exceeding the volatilization temperature of the solvent to burn the powder. Specifically, it is preferable to bake the powder after the metal foil to which the dispersion has been applied is held at a temperature equal to or higher than the boiling point of the solvent.

The "volatilization temperature of the solvent" is preferably within a range of from. + -. 50 ℃ of the boiling point of the solvent, more preferably from the boiling point of the solvent, and still more preferably from +50 ℃ of the boiling point of the solvent. The drying temperature refers to the temperature of the drying atmosphere.

In the drying, the solvent does not have to be completely volatilized, and the solvent may be volatilized to such an extent that the shape of the layer after the retention is stable. Specifically, the amount of the solvent to be volatilized is preferably 50% by mass or more of the solvent contained in the dispersion liquid.

The drying may be performed in 1 stage at a certain temperature, or in 2 stages or more at different temperatures.

Examples of the drying method include a method using an oven, a method using a forced air drying oven, and a method of irradiating heat rays such as infrared rays.

The drying may be carried out under either of normal pressure and reduced pressure.

The drying atmosphere may be any of an oxidizing gas atmosphere (oxygen, etc.), a reducing gas atmosphere (hydrogen, etc.), and an inert gas atmosphere (helium, neon, argon, nitrogen, etc.).

The drying temperature is preferably 50 to 280 ℃, and more preferably 120 to 260 ℃. The drying time is preferably 0.1 to 30 minutes, more preferably 0.5 to 20 minutes.

When the dispersion is dried under the above conditions, the present laminates 1 and 2 can be produced satisfactorily while maintaining high productivity.

Examples of the method of firing include a method using an oven, a method using a through-air drying oven, and a method of irradiating heat rays such as infrared rays.

As a method of firing, a method of irradiating far infrared rays is preferable in view of being able to fire the powder in a short time and being relatively compact in size. The firing method may be a method combining infrared heating and hot air heating.

In order to promote uniform firing of the powder, the effective wavelength band of the far infrared ray is preferably 2 to 20 μm, more preferably 3 to 7 μm.

In addition, in order to improve the surface smoothness of the obtained laminates 1 and 2, the dried product of the dispersion may be pressed with a hot plate, a hot roller, or the like.

The firing may be performed under either normal pressure or reduced pressure. The firing atmosphere may be any of an oxidizing gas atmosphere, a reducing gas atmosphere, and an inert gas atmosphere. However, the firing atmosphere is preferably a reducing gas atmosphere or an inert gas atmosphere from the viewpoint of suppressing the oxidation degradation of the metal foil and the F layer to be formed, respectively.

The firing temperature is set according to the type of the F polymer, and is preferably 180 to 400 ℃, more preferably 200 to 380 ℃, and still more preferably 220 to 370 ℃. The firing temperature is the temperature of the firing atmosphere.

The firing time is preferably 30 seconds to 30 minutes, more preferably 1 to 15 minutes.

When the powder is fired under the above-described conditions, not only the firing of the powder is promoted to improve the productivity of the present laminates 1 and 2, but also the generation of hydrofluoric acid due to the decomposition of the F polymer is easily suppressed.

When D50 of the powder is represented by A and the ten-point average roughness of the surface of the metal foil is represented by B, the ratio B/A is preferably 0.1 to 1.5, more preferably 0.3 to 1.3. When the ratio B/A is within the above range, the anchoring effect of the F layer to the surface of the metal foil (metal foil layers 1 and 2) can be more remarkably exhibited.

The specific value of D50 in the powder is preferably 0.05 to 6 μm, more preferably 0.2 to 3 μm. Within this range, the powder is excellent in flowability and dispersibility, and the electrical characteristics (low dielectric constant, etc.) and heat resistance of the F layer are most easily exhibited.

The D90 of the powder is preferably 8 μm or less, more preferably 5 μm or less. Within this range, the powder is excellent in flowability and dispersibility, and the electrical characteristics (low dielectric constant, etc.) and heat resistance of the F layer are most easily exhibited.

Further, if the powders of D50 and D90 are mentioned above, the anchoring effect of the F layer to the surface of the metal foil (metal foil layers 1 and 2) is more likely to occur.

The bulk density of the powder is preferably 0.05g/mL or more, more preferably 0.08 to 0.5 g/mL. The powder preferably has a dense packing bulk density of 0.05g/mL or more, more preferably 0.1 to 0.8 g/mL. When the loose packing density or the dense packing density is within the above range, the handling of the powder is excellent.

The powder particles of the F polymer are preferably composed of 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.

Examples of the other components that may be contained in the powder particles include aromatic polyesters, polyamide-imides, thermoplastic polyimides, polyphenylene ethers (plain: ポリフェニレンエーテル), polyphenylene ethers (plain: ポリフェニレンオキシド), and the like.

The solvent in the dispersion is a compound which is liquid at 25 ℃, and may be an aqueous solvent or a nonaqueous solvent.

The solvent is preferably water, an amide, an alcohol, a sulfoxide, an ester, a ketone, or a glycol ether, more preferably water, a ketone, or an amide, and further preferably a ketone or an amide. The solvent may be used alone in 1 kind, or in combination of 2 or more kinds.

Specific examples of the solvent include water, methanol, ethanol, isopropanol, N-dimethylformamide, 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, and cellosolve (methyl cellosolve, ethyl cellosolve, and the like).

From the viewpoint of increasing the wettability of the surface of the metal foil with the F polymer and allowing the hydroxyl groups and/or metal atoms on the surface of the metal foil to interact with the oxygen-containing polar groups of the F polymer more favorably, the solvent is preferably a polar solvent, preferably water, an amide, or a ketone, and more preferably water, N-dimethylacetamide, N-methyl-2-pyrrolidone, cyclohexanone, or methyl ethyl ketone.

The dispersion preferably further contains a fluorine-based dispersant. The fluorine-based dispersant is a compound that is chemically and/or physically adsorbed on the surface of the powder particles and has an effect of stably dispersing the powder particles in the solvent. In the dispersion liquid containing the fluorine-based dispersant, the dispersibility of the powder is further improved, the wettability of the surface of the metal foil with the F polymer is increased, and the oxide and/or the metal atom on the surface of the metal foil and the oxygen-containing polar group of the F polymer are likely to have a high degree of interaction.

The fluorine-based dispersant is preferably a compound (surfactant) having a hydrophobic site and a hydrophilic site containing a fluorine atom, more preferably a fluoropolyol, a fluorosilicone, or a fluoropolyether, and further preferably a fluoropolyol.

The fluorine-based dispersant is preferably a nonionic polymer-like compound.

Since the fluorine-based dispersant has a high interaction with the solvent, the coating formability (thixotropic ratio, adhesiveness, transparency, and the like) of the dispersion liquid is easily improved.

The fluorinated polyol is a polymer-like polyol having a hydroxyl group and a fluorine atom, which is different from the F polymer. In addition, a part of the hydroxyl groups of the polymer-like polyol may be chemically modified or modified.

The fluorinated polyol includes a compound having a main chain composed of a carbon chain derived from an ethylenically unsaturated monomer, and a fluorine-containing hydrocarbon group and a hydroxyl group as a side chain branched from the main chain.

In the case of using the dispersion liquid containing the above-mentioned fluoropolyol, the decomposition product of the fluoropolyol at the time of heating after application of the dispersion liquid easily forms an oxide on the surface of the metal foil, and the metal foil (metal foil layers 1 and 2) and the polymer layer are easily adhered more firmly.

The fluoropolyol preferably comprises a copolymer of units based on a fluorine-containing (meth) acrylate having a polyfluoroalkyl group or a polyfluoroalkenyl group and units based on a hydrophilic (meth) acrylate having a polyoxyethylene group or a hydroxyalkyl group. The term "meth (acrylate)" refers to a generic name of acrylate, methacrylate, and acrylate derivatives in which the hydrogen atom at the α -position of acrylate is substituted with another atom or atomic group.

Specific examples of the fluorine-containing (meth) acrylate 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)₄OC(CF₃)(＝C(CF(CF₃)₂)(CF(CF₃)₂)、CH₂＝C(CH₃)COO(CH₂)₂NHCOOCH(CH₂OCH₂CH₂(CF₂)₆F)₂、CH₂＝C(CH₃)COO(CH₂)₂NHCOOCH(CH₂OCH₂(CF₂)₆F)₂、CH₂＝C(CH₃)COO(CH₂)₃NHCOOCH(CH₂OCH₂(CF₂)₆F)₂。

Specific examples of the hydrophilic (meth) acrylate 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)₂(OCH₂CH(CH₃))₁₀OH、CH₂＝CHCOO(CH₂)₂(OCH₂CH₂)₂₃OH、CH₂＝C(CH₃)COO(CH₂)₂(OCH₂CH₂)₂₃OH。

The fluorinated polyol may contain only the fluorine-containing (meth) acrylate-based unit and the hydrophilic (meth) acrylate-based unit, or may further contain other units.

The fluorine content of the fluorinated polyol is preferably 10 to 45 mass%, more preferably 15 to 40 mass%.

The weight average molecular weight of the fluoropolyol is preferably 2000 to 80000, more preferably 6000 to 20000.

As the fluorosilicone, there may be mentioned a polyorganosiloxane having a C-F bond in a part of its side chain.

Further, as the fluoropolyether, a compound in which a part of hydrogen atoms of polyoxyalkylene alkyl ether is substituted with fluorine atoms is exemplified. Further, the fluoropolyether also contains a monool of the above-mentioned compound.

Further, the dispersion may also contain other materials. The other materials may or may not be soluble in the dispersion.

The other material may be a non-curable resin or a curable resin.

Examples of the non-curable resin include a hot-melt resin and a non-melt resin. As the hot-melt resin, thermoplastic polyimide is exemplified. Examples of the non-fusible resin include cured products of curable resins.

Examples of the curable resin include a polymer having a reactive group, an oligomer having a reactive group, a low-molecular compound, and a low-molecular compound having a reactive group. Examples of the reactive group include a carbonyl group, a hydroxyl group, an amino group, and an epoxy group.

Examples of the curable resin include: epoxy resins, thermosetting polyimides, polyamic acids which are precursors of polyimides, acrylic resins, phenolic resins, polyester resins, polyolefin resins, modified polyphenylene ether resins, polyfunctional cyanate ester resins, polyfunctional maleimide-cyanate ester resins, polyfunctional maleimide resins, vinyl ester resins, urea resins, diallyl phthalate resins, melamine resins, guanamine resins, melamine-urea copolycondensation resins.

Specific examples of the epoxy resin include various types of epoxy resins (naphthalene type, cresol novolak type, bisphenol a type, bisphenol F type, bisphenol S type, alicyclic type, aliphatic chain type, cresol novolak type, phenol novolak type, alkylphenol novolak type, aralkyl type, bisphenol type) and the like.

Examples of the bismaleimide resin include a resin composition (BT resin) disclosed in Japanese patent application laid-open No. Hei 7-70315 and a resin disclosed in International publication No. 2013/008667.

The polyamic acid generally has a reactive group that can react with the oxygen-containing polar group of the F polymer.

Examples of the diamine and polycarboxylic acid dianhydride for forming polyamic acid include those described in paragraph [0020] of Japanese patent No. 5766125, paragraph [0019] of Japanese patent No. 5766125, and paragraphs [0055] and [0057] of Japanese patent laid-open Nos. 2012 and 145676.

Examples of the hot-melt resin include thermoplastic resins such as thermoplastic polyimides and hot-melt cured products of curable resins.

Examples of the thermoplastic resin include polyester resins, polyolefin resins, styrene resins, polycarbonates, thermoplastic polyimides, polyarylates, polysulfones, polyarylsulfones, aromatic polyamides, aromatic polyetheramides, polyphenylene sulfides, polyaryletherketones, polyamideimides, liquid crystalline polyesters, and polyphenylene ethers, and preferably thermoplastic polyimides, liquid crystalline polyesters, or polyphenylene ethers.

Further, as other materials, thixotropy imparting agents, antifoaming agents, inorganic fillers, reactive alkoxysilanes, dehydrating agents, plasticizers, weather-resistant agents, antioxidants, heat stabilizers, lubricants, antistatic agents, whitening agents, colorants, conductive agents, mold release agents, surface treatment agents, viscosity modifiers, and flame retardants can be cited.

The viscosity of the dispersion is preferably 50 to 10000 mPas, more preferably 75 to 1000 mPas, and further preferably 100 to 500 mPas. In this case, not only the dispersion has excellent dispersibility, but also the coatability and compatibility between varnishes of different resin materials are excellent.

The thixotropic ratio of the dispersion is preferably 1.0 to 2.2, more preferably 1.4 to 2.2, and still more preferably 1.5 to 2.0. In this case, not only the dispersibility of the dispersion is excellent, but also the homogeneity of the F layer is easily improved. The thixotropic ratio was calculated by dividing the viscosity of the dispersion measured at a rotation speed of 30rpm by the viscosity of the dispersion measured at a rotation speed of 60 rpm.

In the method of thermocompression bonding the film containing the F polymer on the surface of the metal foil, the F layer is formed by thermocompression bonding the film containing the F polymer on the surface of the metal foil, and the present laminates 1 and 2 having the F layer provided in direct contact on the surfaces of the metal foil layers 1 and 2 composed of the metal foil are obtained.

The film can be produced by a method of forming the F polymer itself or a composition containing the F polymer into a film shape by an extrusion molding method, an inflation molding method, or the like.

Specifically, the laminate is produced through a preliminary heating step of heating a pseudo laminate in the thickness direction (lamination direction) without applying pressure while conveying the pseudo laminate in which a film is laminated on the surface of a metal foil, and a thermal compression bonding step of applying pressure in the thickness direction (lamination direction) while heating the pseudo laminate.

The quasi-laminate is in a state where the metal foil and the film are in close contact with each other but not yet bonded (pressure-bonded).

Before forming the quasi-laminate, the film may be subjected to a preliminary heat treatment at a temperature of 100 ℃ or higher and less than 250 ℃ (preferably 180 ℃ or higher and less than 250 ℃). By performing the preliminary heating treatment, film shrinkage in the preliminary heating step and the thermocompression bonding step can be reduced, and as a result, warpage of the laminate can be reduced.

Before the formation of the pseudo laminate, the surface of the film (the surface on the metal foil side) may be subjected to a surface treatment such as corona discharge treatment or plasma treatment. When the pre-surface treatment is performed, the number of oxygen-containing polar groups present on the surface of the film can be increased, and the adhesion strength of the F layer to the metal foil layers 1 and 2 in the obtained laminate is further improved.

In the preliminary heating step, the laminate is heated by the preliminary heating means without being pressed in the lamination direction (thickness direction) before being subjected to pressure bonding with the laminate in the subsequent thermal compression bonding step.

The preheating means may be a contact type in which the heat source is brought into contact with the pseudo laminate, or a non-contact type in which the pseudo laminate is heated in a non-contact manner. The preheating means is preferably a contact type in view of the ease of adhesion between the metal foil and the film. Specifically, the quasi-laminate is preferably conveyed in a state of being in contact with a heated metal roll.

In the thermocompression bonding step, the temperature of the preliminary stacked body immediately before pressing (the temperature of preliminary heating) is preferably lower than the melting temperature of the F polymer by 20 ℃ or more, and more preferably higher than the melting temperature of the F polymer. The temperature of the preheating is preferably not higher than the temperature of the thermocompression bonding. By setting the temperature of the preliminary heating to the above range, shrinkage or breaking of the film can be favorably prevented.

In the preliminary heating step, the pseudo laminate may be heated continuously or intermittently. The transport time (preheating time) from the time when preheating is started for the quasi-stacked body being transported to the time when the quasi-stacked body is immediately pressurized in the thermocompression bonding step is preferably 10 to 30 seconds. By setting the preheating time within the above range, not only shrinkage or breaking of the film can be favorably suppressed, but also the adhesion of the F layer to the metal foil layers 1 and 2 in the obtained laminate is improved.

In the case where the preliminary heating step is performed by the contact type preliminary heating means, if the preliminary heating time is within the above range, the temperature of the pseudo laminate body is the same as the surface temperature of the heat source in contact with the pseudo laminate body.

The thermocompression bonding step is preferably performed continuously using a thermocompression bonding apparatus or the like provided with a pair of thermocompression bonding means or more. The thermocompression bonding means is a means for performing pressure bonding by heating and pressing the quasi-stacked body. As the thermocompression bonding means, a heat roller bonding device provided with a pair of or more metal rollers is preferably used.

In the hot-rolling device, when the quasi-laminate passes between a pair of metal rollers heated to a predetermined temperature, the quasi-laminate is heated by contact with the metal rollers and is subjected to a pressure in the thickness direction, whereby the film is pressure-bonded to the metal foil. The quasi-laminate may be configured by sequentially passing a plurality of pairs of metal rolls.

The surface temperature of the metal roll pressed against the laminate (the temperature of thermocompression bonding) is preferably not less than the melting temperature of the F polymer, and more preferably not less than 400 ℃. In this case, good adhesion strength of the F layer to the metal foil layers 1 and 2 can be obtained, and peeling is less likely to occur.

The pressure between a pair of metal rolls (pressure for thermocompression bonding) for pressing the laminate is preferably 98 to 1470N/cm in terms of the roll line pressure represented by the load applied to the rolls per 1cm width. In this case, the film is not easily broken during thermocompression bonding, and good adhesion strength of the F layer to the metal foil layers 1 and 2 can be obtained, and peeling is not easily caused.

The running speed (speed of thermocompression bonding) of the quasi-laminate when passing between the pair of metal rolls is preferably 0.5 m/min or more, more preferably 1 m/min or more. In this case, thermal compression bonding can be sufficiently performed, and the productivity of the present laminates 1 and 2 can be further improved. The speed of the thermocompression bonding is preferably 8 m/min or less. In this case, the F layer is easily strongly bonded to the metal foil layers 1 and 2.

The film may be a laminated film in which a film (base film) containing an F polymer has a heat-resistant resin film on the opposite side of the metal foil.

The heat-resistant resin film contains a heat-resistant resin and may contain additives and the like as necessary.

From the viewpoint of improving the heat resistance of the heat-resistant resin film, 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.

Examples of the heat-resistant resin include polyimide (aromatic polyimide, etc.), polyarylate, polysulfone, polyarylsulfone (polyethersulfone, etc.), aromatic polyamide, aromatic polyetheramide, polyphenylene sulfide, polyaryletherketone, polyamideimide, and liquid crystal polyester.

The heat-resistant resin is preferably a thermosetting resin or a resin blend in view of easy availability of high heat resistance.

Examples of the thermosetting resin include thermosetting polyimide, epoxy resin, and acrylic resin. The thermosetting resin is preferably a thermosetting polyimide in view of improving the electrical characteristics of the laminate.

As the thermosetting polyimide, an aromatic polyimide is preferable, and a wholly aromatic polyimide produced by polycondensation of an aromatic dicarboxylic acid and an aromatic diamine is more preferable.

As the additive, an inorganic filler having a low relative dielectric constant and a low dielectric loss tangent is preferable.

Examples of the inorganic filler include silica, clay, talc, calcium carbonate, mica, diatomaceous earth, alumina, zinc oxide, titanium oxide, calcium oxide, magnesium oxide, iron oxide, tin oxide, antimony oxide, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, basic magnesium carbonate, zinc carbonate, barium carbonate, dawsonite (ドーソナイト), hydrotalcite, calcium sulfate, barium sulfate, calcium silicate, montmorillonite, bentonite, activated clay, sepiolite, imogolite, sericite, glass fiber, glass bead, silica-like hollow sphere (シリカ system バルーン), carbon black, carbon nanotube, carbon nanohorn, graphite, carbon fiber, hollow glass sphere (ガラスバルーン), carbon silo (carbon element バーン), wood powder, and zinc borate. The inorganic filler may be used alone in 1 kind, or may be used in combination of 2 or more kinds.

In the laminates 1 and 2, the peel strength of the layer F to the metal foil layers 1 and 2 is preferably 10N/cm or more, and more preferably 15N/cm or more. In addition, the upper limit of the peel strength is usually 20N/cm.

The warpage of the present laminates 1 and 2 is preferably 25% or less, more preferably 7% or less. In this case, the present laminates 1 and 2 are excellent in workability when processed into a printed wiring board and in transmission characteristics of the resulting printed wiring board.

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, the present laminates 1 and 2 can be easily processed into a printed wiring board and then multilayered.

The surface of the F layer preferably has a water contact angle of 70 to 100 degrees, more preferably 70 to 90 degrees. In this case, the F layer is more excellent in adhesion to other substrates. When the above range is not less than the lower limit, the electrical characteristics when the present laminates 1 and 2 are processed into a printed wiring board are more excellent.

The thickness of the F layer is preferably 1 to 50 μm, more preferably 5 to 15 μm. Within this range, the electrical characteristics of the present laminates 1 and 2 when processed into a printed wiring board and the warpage-suppressing effect of the laminates are easily balanced.

In addition, in the case where the present laminates 1 and 2 have F layers on both surfaces of the metal foil layers 1 and 2, the composition and thickness of each F layer are preferably the same from the viewpoint of suppressing warpage of the present laminates 1 and 2.

The relative dielectric constant of the F layer is preferably 1.98 or less, more preferably 1.95 or less. The lower limit of the relative dielectric constant of the F layer is generally 1.50.

The dielectric loss tangent of the F layer is preferably 0.0024 or less, more preferably 0.0019 or less. The lower limit of the dielectric loss tangent of the F layer is usually 0.0005.

In this case, the laminates 1 and 2 can be suitably used for printed wiring boards and the like which require a low dielectric constant.

The relative permittivity and the dielectric loss tangent of the F layer were measured at a measurement frequency of 10GHz by a cavity resonator perturbation method using a network analyzer as a measuring instrument.

The present laminates 1 and 2 can be processed into a printed wiring board.

For example, a printed wiring board can be manufactured from the laminates 1 and 2 by using a method of processing a conductor circuit (patterned circuit) having a predetermined pattern by etching or the like of the metal foil layers 1 and 2 of the laminates 1 and 2, or a method of processing a patterned circuit by plating (a semi-additive process (SAP process), an improved semi-additive process (MSAP process), or the like) of the laminates 1 and 2.

In the production of the printed wiring board, after the formation of the patterned circuit, an interlayer insulating film may be formed on the patterned circuit, and a conductor circuit may be further formed on the interlayer insulating film. The interlayer insulating film may be formed from the dispersion liquid.

In the production of a printed wiring board, a solder resist may be laminated on a patterned circuit. The solder resist may be formed from the dispersion.

In the production of a printed wiring board, a cover lay film may be laminated on a patterned circuit. The coating film may be formed from the dispersion.

The method for producing a composite laminate (composite of the present invention) of the present invention is a method for obtaining a composite laminate in which at least a polymer layer and a prepreg layer are laminated by removing at least a part of a metal foil layer having a predetermined laminate (a metal foil with an F layer) and bonding the prepreg to an exposed polymer layer.

When the metal foil layer is entirely removed, a composite laminate having 2 layers of a polymer layer and a prepreg layer can be obtained. When a circuit pattern is formed by removing a part of the metal foil layer, a composite laminate having 3 layers of a polymer layer, a prepreg layer, and a circuit pattern sandwiched therebetween can be obtained. The latter composite laminate can be suitably used as a printed wiring board.

A laminate used for producing a composite laminate comprises a metal foil layer having a surface with a ten-point average roughness of 0.1 [ mu ] m or more and an F layer laminated on the surface thereof.

The surface of the metal foil layer has a ten-point average roughness of 0.1 [ mu ] m or more and has minute irregularities. The F layer formed on the surface transfers the surface shape of the metal foil layer on the contact surface with the metal foil layer. Therefore, minute irregularities corresponding to the surface shape of the metal foil layer are irregularly present on the contact surface of the F layer exposed by removing the metal foil layer.

In the present invention, since the prepreg is bonded to the contact surface having the above surface properties to obtain a composite laminate, it is considered that the prepreg exerts a high anchoring effect on the contact surface of the F layer. As a result, it is presumed that a high adhesion force (peel strength) is exhibited between the F layer and the prepreg layer.

The above effects are remarkably exhibited in the preferred embodiment of the present invention described later.

The form (including the preferred form) of the F polymer in the method for producing the composite is the same as the form of the F polymer in the laminate.

The form (including the preferred form) of the metal constituting the metal foil layer in the method for producing the composite is the same as the form of the metal constituting the metal foil layer in the laminate.

In the method for producing the composite, the ten-point average roughness of the surface of the metal foil layer is 0.1 μm or more, preferably 0.3 μm or more. The ten-point average roughness is preferably 7 μm or less, more preferably 2.5 μm or less, and still more preferably 2 μm or less. If the ten-point average roughness is within the above range, the degree of unevenness of the surface of the metal foil layer is not excessively large, and therefore, even when the present composite is processed into a printed wiring board, an increase in transmission loss can be suppressed. In addition, when a prepreg is laminated, the matrix resin of the prepreg is compatible with the F polymer, and the interlayer adhesion is likely to be further improved.

In the present method for producing a composite, when the metal foil layer has a roughened layer, the ten-point average roughness of the surface can be adjusted by setting the size of the metal particles, the number of the metal particles, and the like.

The plating conditions may be the same as those in the present laminate.

The surface of the metal foil layer may be subjected to roughening treatment such as dry etching or wet etching to adjust the ten-point average roughness of the surface to be within the above range.

In addition, the metal foil layer may further include at least 1 layer of a heat-resistant treatment layer, a rust-preventive treatment layer, and a chromate treatment layer, from the viewpoint of improving various properties. In the case where the metal foil layer is formed by lamination, these layers may be provided between the surfaces of the roughening-treated layer opposite to the base material layer or between the roughening-treated layer and the metal foil. The heat-resistant layer, the rust-preventive layer, or the chromate layer can be formed by a known method. In addition, in the case where the heat-resistant treatment layer, the rust-preventive treatment layer, or the chromate treatment layer constitutes the outermost layer of the metal foil layer, the surface thereof constitutes the surface of the metal foil layer.

The thickness of the metal foil layer may be the same as that of the metal foil layer of the laminate.

In the method of producing the present composite, the forms of the F layer (including its preferred form and its method of formation) are the same as those in the present laminate.

In the method for producing the composite, the metal foil layer is preferably removed by wet etching. The wet etching can prevent damage to the minute uneven shape transferred on the contact surface of the F layer, and can accurately and sufficiently remove the unnecessary portion of the metal foil layer.

Further, the wet etching is preferably performed using an acid solution. When the F polymer has a hydrolyzable acid anhydride residue as the oxygen-containing polar group, the oxygen-containing polar group is activated by the acid solution, and therefore the adhesion between the F layer and the prepreg layer is easily further improved. Here, as an example of activation of the oxygen-containing polar group, conversion of an acid anhydride group into a 1, 2-dicarboxylic acid group can be mentioned.

The acid solution may be an aqueous solution of an inorganic acid such as hydrochloric acid, dilute nitric acid, or hydrofluoric acid.

A prepreg is a sheet-like substrate obtained by impregnating a matrix resin into a base material (e.g., chopped jute, woven fabric, etc.) of reinforcing fibers (e.g., glass fibers, carbon fibers, etc.). The matrix resin may be a thermoplastic resin or a thermosetting resin. That is, the prepreg layer is a layer formed of a prepreg. The prepreg layer is a layer containing a cured product of a matrix resin when the matrix resin is curable, and a layer containing a molten cured product of the matrix resin when the matrix resin is thermoplastic.

Examples of the thermosetting resin include the resins listed in the description of the dispersion, and epoxy resin, polyoxyxylene, polyphenylene ether, and polybutadiene are preferable. The polyphenylene ether is preferably a modified polyphenylene ether, more preferably a polyphenylene ether having a vinyl group.

The thermoplastic resin may be the resin listed in the description of the dispersion.

The matrix resin may be used alone in 1 kind, or in combination of 2 or more kinds.

As the matrix resin of the prepreg, an epoxy resin, polyoxyxylene, polyphenylene ether, or polybutadiene is preferable from the viewpoint of processability.

When the matrix resin is a thermosetting resin, the prepreg preferably contains a curing agent, and more preferably contains a curing agent having 3 or more curable groups (isocyanate groups, blocked isocyanate groups, and the like) in 1 molecule.

As the matrix resin, a resin having a fluorine atom can be used. Examples of the resin include an F polymer, polyimide having a fluorine atom, and epoxy resin having a fluorine atom.

Preferred embodiments of the matrix resin include an embodiment composed of only a matrix resin having no fluorine atom, and an embodiment composed of a matrix resin having no fluorine atom and a matrix resin having a fluorine atom.

Examples of the reinforcing fiber sheet include a reinforcing fiber bundle composed of a plurality of reinforcing fibers, a woven fabric woven from the reinforcing fiber bundle, a unidirectional reinforcing fiber bundle in which a plurality of reinforcing fibers are aligned in one direction, a unidirectional woven fabric composed of the unidirectional reinforcing fiber bundle, or a combination thereof, and a laminate of a plurality of reinforcing fiber bundles.

The reinforcing fiber is preferably a continuous long fiber having a length of 10mm or more. The reinforcing fibers do not have to be continuous over the entire length or the entire width of the reinforcing fiber sheet, and may be cut off halfway. The reinforcing fiber may be subjected to a surface treatment such as a silane coupling agent treatment.

Examples of the reinforcing fibers include inorganic fibers, metal fibers, and organic fibers.

Examples of the 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 the metal fibers include aluminum fibers, brass fibers, and stainless steel fibers.

Examples of the organic fiber include an aramid fiber, a polyaramide fiber, a polyparaphenylene benzobisoxazole (ポリパラフェニレンベンズオキサゾール) (PBO) fiber, a polyphenylene sulfide fiber, a polyester fiber, an acrylic fiber, a nylon fiber, and a polyethylene fiber.

The reinforcing fibers may be used alone in 1 kind, or in combination of 2 or more kinds.

For use as a material for printed boards, glass fibers are preferred as the reinforcing fibers.

The method of bonding the prepreg to the F layer is preferably a method of bringing the prepreg into contact with the contact surface of the F layer, at least a part of which is exposed, of the laminate and performing thermocompression bonding.

The temperature of the thermocompression bonding is preferably not higher than the melting temperature of the F polymer, more preferably 120 to 300 ℃, and further preferably 160 to 220 ℃. Within this range, thermal degradation of the prepreg can be suppressed, and the polymer layer can be firmly bonded to the prepreg.

The pressure bonding pressure for the thermocompression bonding is preferably 0.2MPa or more. The pressure is preferably 10MPa or less, more preferably 4MPa or less. Within this range, breakage of the prepreg can be suppressed, and the F layer and the prepreg can be more firmly bonded.

Further, in the case where the prepreg is thermally press-bonded to the contact surface of the F layer at the above-mentioned thermal temperature or pressure, the prepreg layer embedded in the F layer is more compatible and integrated with the F polymer due to the anchoring effect, and the adhesion is easily further improved.

The thermocompression bonding is preferably performed in a reduced pressure atmosphere, and more preferably in a vacuum degree of 20kPa or less. Within this range, air bubbles can be prevented from entering the interface between the F layer and the prepreg layer, and deterioration due to oxidation of the composite can be prevented.

In the hot pressing, it is preferable to raise the temperature after the degree of vacuum is reached. This makes it possible to perform pressure bonding in a state before the F layer is softened, that is, in a state before a certain degree of fluidity and adhesion is exhibited, and thus, generation of bubbles can be prevented.

According to the method for producing the composite, since the prepreg layer is laminated on the F layer having a strong adhesive force to which the roughness of the metal foil layer is transferred, the F layer can be directly adhered to the prepreg layer without hydrophilizing the surface of the exposed F layer (contact surface). The hydrophilization treatment is a treatment for lowering the contact angle of the surface of the exposed F layer with water, and specifically includes a plasma treatment, an electron beam treatment, or a treatment using a silane coupling agent.

In the present composite, the peel strength of the F layer from the prepreg layer is preferably 10N/cm or more, more preferably 15N/cm or more. In addition, the upper limit of the peel strength is usually 20N/cm.

The warpage of the present composite is preferably 25% or less, more preferably 7% or less. In this case, the composite (printed wiring board) has excellent transmission characteristics.

The dimensional change rate of the present composite is preferably ± 1% or less, more preferably ± 0.2% or less. In this case, the present composite can be easily multilayered.

In the method for producing the composite, a processed laminate in which a metal circuit layer (circuit pattern) is formed from a metal foil layer by removing a part of the metal foil layer of the laminate can be used as a printed circuit board having excellent reflow soldering resistance.

For example, a multilayer printed wiring board having a multilayer structure of the above-described printed wiring board and an F layer as the outermost layer is excellent in heat resistance, and specifically, expansion at the interface of the prepreg layer and peeling at the interface of the metal circuit layer are less likely to occur even at 288 ℃. In particular, when the F layer has a predetermined thickness (1 to 15 μm, particularly 3 to 9 μm), the above tendency is more pronounced.

Further, the multilayer printed wiring board having the multilayer structure of the printed wiring board and the prepreg layer as the outermost layer is excellent in heat resistance, and specifically, expansion at the interface of the prepreg layer and peeling at the interface of the metal circuit layer are less likely to occur even at 300 ℃. In particular, when the F layer has a predetermined thickness (1 to 15 μm, particularly 3 to 9 μm), the above tendency is more pronounced.

Further, according to the present invention, there is provided a method for producing a laminate (F-layer-provided metal foil) comprising removing at least a part of a metal foil having 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, applying a solder resist to the exposed F layer, curing the solder resist to form a solder mask layer, and laminating at least the F layer and the solder mask layer to form a laminate.

In this manufacturing method, the forms of the metal foil (metal foil layer), the F polymer, the F layer, the laminate, and the metal foil layer excluding at least a part of the laminate are included in suitable ranges, and are the same as those in the manufacturing method of the present composite.

As the solder resist, a known solder resist can be used. The application and curing of the solder resist may be appropriately determined depending on the type of the solder resist used.

In this manufacturing method, it is preferable that the surface of the exposed F layer is treated with an acid solution, and the solder resist is directly applied and cured. In this case, when the solder mask layer is formed, the solder mask layer having excellent adhesion can be more easily formed than when the surface treatment (polishing) is performed after the acid treatment.

In the method for producing a polymer film of the present invention, the metal foil layer of the laminate (F-layer-attached metal foil) may be entirely removed, and the remaining monomer F layer may be used as a polymer film.

The polymer film can be used as an adhesive layer, an interlayer insulating film, a solder resist layer, a coating film, or the like for bonding 2 substrates.

The laminate and the method for producing the same, the method for producing the composite laminate, and the method for producing the polymer film of the present invention have been described above, but the present invention is not limited to the configuration of the above embodiment.

For example, in the structure of the above embodiment, the laminate of the present invention may have any other structure added thereto or may be replaced with any structure that exhibits the same function.

In the configuration of the above embodiment, other arbitrary steps may be added to the method for producing a laminate, the method for producing a composite laminate, and the method for producing a polymer film according to the present invention, or may be replaced with arbitrary steps that exhibit the same function.

Examples

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

1. Preparation of the Components and Components

[ F Polymer ]

F, polymer 1: a copolymer comprising TFE-based units, NAH-based units and PPVE-based units in this order in the order of 98.0 mol%, 0.1 mol% and 1.9 mol% (melting temperature: 300 ℃, melt viscosity at 380 ℃: 3X 10⁵Pa·s)

F, polymer 2: copolymer having no oxygen-containing polar group comprising TFE-based unit and PPVE-based unit in this order of 98.0 mol% and 2.0 mol% (melting temperature: 305 ℃, melt viscosity at 380 ℃: 3X 10⁵Pa·s)

Polymer F3: copolymer having no functional group comprising TFE-based unit and PPVE-based unit in this order of 97.5 mol% and 2.5 mol% (melting temperature: 305 ℃, melt viscosity at 380 ℃: 3X 10⁵Pa·s)

[ powder ]

Powder 1: powder composed of F Polymer 1 (D50: 2.6 μm, D90: 7.1 μm)

Powder 2: powder composed of F Polymer 2 (D50: 3.5 μm, D90: 9.2 μm)

Powder 3: powder composed of F Polymer 2 (D50: 1.8 μm, D90: 4.9 μm)

Powder 4: powder composed of F Polymer 1 (D50: 1.8 μm, D90: 5.2 μm)

Powder 5: powder composed of F Polymer 3 (D50: 1.9 μm, D90: 5.5 μm)

Further, D50 and D90 were measured by dispersing the powder in water using a laser diffraction/scattering particle size distribution measuring device (manufactured by horiba, japan), LA-920 measuring device.

[ fluorine-based dispersant ]

FP 1: is a nonionic fluoro polyol, CH₂＝CHCOO(CH₂)₄OCF(CF₃)(C(CF(CF₃)₂)(＝C(CF₃)₂) And CH₂＝CHCOO(CH₂)₄(OCH₂CH₂)₁₀Copolymers of OH

[ sheet ]

Sheet 1: sheet composed of F Polymer 1 (thickness: 10 μm)

Sheet 2: sheet composed of F Polymer 3 (thickness: 10 μm)

[ prepreg ]

Prepreg 1: thermosetting resin composition comprising polyphenylene ether resin, glass fiber and silica filler

2. Preparation of the Dispersion

(Dispersion 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 put into a pot, and then zirconia balls were put into the pot. Thereafter, the pot was rolled at 150rpm for 1 hour to disperse the powder 1 in NMP, thereby obtaining a dispersion 1.

(Dispersion 2)

Dispersion 2 was prepared in the same manner as dispersion 1 except that powder 1 was changed to powder 2.

(Dispersion 3)

Dispersion 3 was prepared in the same manner as dispersion 1 except that powder 1 was changed to powder 3.

(Dispersion 4)

Dispersion 4 was obtained in the same manner as in dispersion 1 except that powder 1 was changed to powder 4 and the amount of FP1 was changed to 3 parts by mass.

(Dispersion 5)

Dispersion 5 was obtained in the same manner as in dispersion 1 except that powder 1 was changed to 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) having a thickness of 12 μm was used as a cathode, and electroplating was performed under the following conditions to form a roughened layer on the surface of the rolled copper foil. Thereby, the metal foil 1 is produced.

Thereafter, a heat-resistant treatment layer and a chromate layer are sequentially formed on the surface of the roughened treatment layer.

The thickness of the metal foil 1 was 15 μm, and the ten-point average roughness of the surface was 0.6 μm.

(1) > < 1 time particle plating

The liquid composition is as follows: 11g/L of copper sulfate pentahydrate and 52g/L of sulfuric acid

Liquid temperature: 22 deg.C

Current density: 40A/dm²

Electroplating time: 1 second

(2) > < 1 time particle plating

The liquid composition is as follows: 19g/L of copper sulfate pentahydrate and 101g/L of sulfuric acid

Liquid temperature: 42 deg.C

Current density: 4A/dm²

Electroplating time: 3 seconds

< 2 times particle plating >

The liquid composition is as follows: 15g/L of copper sulfate pentahydrate, 10g/L of nickel sulfate hexahydrate,

7g/L of cobalt sulfate heptahydrate

Liquid temperature: 37 deg.C

Current density: 30A/dm²

Electroplating time: 1 second

(Metal foil 2)

The surface of the metal foil 1 was subjected to surface treatment using a solution containing 1 vol% of a silane coupling agent ("KBM series" manufactured by shin-Etsu chemical Co., Ltd. (shin-Etsu chemical Co., Ltd.) under the following conditions to obtain a metal foil 2.

The thickness of the metal foil 2 was 15 μm, and the ten-point average roughness of the surface was 0.6 μm.

< treatment Condition >

Temperature of the solution: 20 deg.C

pH of the solution: 4.5

Treatment time: 3 seconds

Coating times: 1 time of

Drying temperature: 110 deg.C

Drying time: 30 seconds

(Metal foil 3)

Using platinum group metal oxide-coated titanium as an anode and an electrolytic copper foil having a ten-point average roughness (Rzjis) of 0.75 μm and a thickness of 12 μm as a cathode, electroplating was performed under the following conditions to form a roughened layer on the surface of the electrolytic copper foil, thereby obtaining a metal foil 3.

< plating Condition >

The liquid composition is as follows: 15g/L of copper sulfate pentahydrate, 8.5g/L of cobalt sulfate heptahydrate,

Nickel sulfate hexahydrate 1.7g/L

pH value: 2.5

Liquid temperature: 38 deg.C

Current density: 45A/dm²

Electroplating time: 1 second

Further, the ten-point average roughness of the surface of the metal foil 3 was 1.0. mu.m.

The measurement diameter is set as

The surface of the metal foil 3 (roughened layer) was analyzed by a fluorescent X-ray analyzer (ZSX primus ii manufactured by shinko corporation, ltd. リガク). As a result, the proportion of nickel atoms (mass of nickel atoms/mass of all atoms) was 0.06 mass%.

(Metal foil 4)

The metal foil 4 was produced in the same manner as the metal foil 3 except that the liquid composition was changed as shown below.

The liquid composition is as follows: 15g/L of copper sulfate pentahydrate and 8.5g/L of cobalt sulfate heptahydrate

The ten-point average roughness of the surface of the metal foil 4 was 1.0 μm. The ratio of nickel atoms present on the surface of the metal foil 4 (roughened layer) measured in the same manner as described above was 0.00 mass%.

(Metal foil 5)

The metal foil 5 was produced in the same manner as the metal foil 3 except that the liquid composition was changed as shown below.

Nickel sulfate hexahydrate 8.6g/L

Further, the ten-point average roughness of the surface of the metal foil 5 was 1.0. mu.m. The ratio of nickel atoms present on the surface of the metal foil 5 (roughened layer) measured in the same manner as described above was 0.30 mass%.

(Metal foil 6)

After the electrolytic copper foil is subjected to plating treatment to form a roughened layer, a heat-resistant treatment layer and a chromate layer are formed in this order on the roughened layer to produce a metal foil 6. The ten-point average roughness of the surface of the metal foil 6 was 0.2 μm, and the thickness was 12 μm.

(Metal foil 7)

The metal foil 7 is manufactured in the same manner as the metal foil 6. The ten-point average roughness of the surface of the metal foil 7 was 1.2 μm, and the thickness was 18 μm.

(Metal foil 8)

The metal foil 8 is manufactured in the same manner as the metal foil 6. The ten-point average roughness of the surface of the metal foil 8 was 7.7 μm, and the thickness was 18 μm.

4. Production of laminate

(example 1)

First, the dispersion 1 is applied roll-to-roll to the surface of the metal foil 1 by a die coating method to form a liquid coating film. Then, the metal foil 1 on which the liquid coating film was formed was passed through a drying furnace at 120 ℃ for 30 minutes, and dried by heating. Thereafter, the dried film was heated at 380 ℃ for 15 minutes in a nitrogen furnace. Thereby, a laminate 1 having an F layer formed on the surface of the metal foil 1 was produced.

Example 2 (comparative example)

A laminate 2 was produced in the same manner as in example 1, except that the metal foil 1 was changed to the metal foil 2.

Example 3 (comparative example)

A laminate 3 was produced in the same manner as in example 1, except that the dispersion liquid 1 was changed to the dispersion liquid 2.

(example 4)

A laminate 4 having an F layer thickness of 12 μm was produced in the same manner as in example 1, except that the metal foil 1 was changed to the metal foil 3.

Further, using 2 sheets of the laminate 4 and 1 sheet of a polyimide film ("UPILEX 25S" made by Yukeng corporation (thickness: 25 μm)), the F layer of each laminate 1 was brought into contact with each of both surfaces of the polyimide film, and the laminate 41 having metal foil layers on both outermost surfaces was produced by heat lamination at 360 ℃.

Example 5 (comparative example)

A laminate 5 and a laminate 51 each having an F layer thickness of 12 μm were produced in the same manner as in example 4, except that the metal foil 3 was changed to the metal foil 4.

Example 6 (comparative example)

A laminate 6 and a laminate 61 each having an F layer thickness of 12 μm were produced in the same manner as in example 4, except that the metal foil 3 was changed to the metal foil 5.

Example 7 (comparative example)

A laminate 7 having an F layer thickness of 12 μm was produced in the same manner as in example 4, except that the dispersion liquid 1 was changed to the dispersion liquid 3.

(example 8)

First, the dispersion 4 is applied roll-to-roll by the gravure reverse method to the surface of the metal foil 7 to form a liquid coating film. Then, the metal foil 7 on which the liquid coating film was formed was passed through a drying oven at 100 ℃, 120 ℃ and 140 ℃ for 5 minutes, and dried by heating. Thereafter, the dried film was heated at 380 ℃ for 3 minutes in a far infrared oven under a nitrogen atmosphere. Thereby, the laminate 8 having the F layer formed on the surface of the metal foil was produced. The thickness of the F layer was 5 μm.

After the vacuum plasma treatment was performed on the F layer side of the laminate 8, the F layer of the laminate 8 and the prepreg 1 were laminated, and thermocompression bonding was performed at a temperature of 200 ℃, a pressure of 3MPa, and a time of 15 minutes. Thereafter, the metal foil layer of the laminate 8 was completely removed with an acid solution, and the prepreg 1 was directly laminated on the contact surface (exposed surface) thereof, and thermocompression bonded under conditions of a temperature of 200 ℃, a pressure of 3MPa, and a time of 15 minutes. Thereby, a composite laminate 8 in which the exposed F layer and the prepreg layer are laminated is obtained.

(example 9)

A composite laminate 9 was produced in the same manner as in example 8, except that the metal foil 7 was changed to the metal foil 6 and the dispersion liquid 4 was changed to the dispersion liquid 5.

(example 10)

A composite laminate 10 was produced in the same manner as in example 8, except that the dispersion liquid 4 was changed to the dispersion liquid 5.

Example 11 (comparative example)

Composite laminate 11 was produced in the same manner as in example 10, except that metal foil 7 was changed to metal foil 8 and the thickness of the F layer was changed to 15 μm.

(example 12)

First, the sheet 1 was laminated on the surface of the metal foil 7, and thermocompression bonded at 380 ℃ for 3 minutes in a furnace under a nitrogen atmosphere. Thereby, a laminate having an F layer formed on the surface of the metal foil was produced.

After the vacuum plasma treatment was performed on the F layer side of the laminate, the F layer of the laminate and the prepreg 1 were laminated, and thermocompression bonding was performed under conditions of a temperature of 200 ℃, a pressure of 3MPa, and a time of 15 minutes. Thereafter, the metal foil layer of the laminate was completely removed with an acid solution, and the prepreg 1 was directly laminated on the contact surface (exposed surface) thereof, and thermocompression bonded at a temperature of 200 ℃, a pressure of 3MPa, and a time of 15 minutes. Thereby, a composite laminate 12 in which the exposed F layer and the prepreg layer are laminated is obtained.

(example 13)

A composite laminate 13 was produced in the same manner as in example 12, except that the sheet 1 was changed to the sheet 2.

5. Evaluation of laminate

5-1 peeling Strength between Metal foil layer and F layer of laminate (1 thereof)

The laminates of examples 1 to 3 were cut into rectangles (100 mm in length and 10mm in width), and 50 samples were prepared. Thereafter, one end of each sample in the longitudinal direction was fixed at a position of 50mm, and the metal foil layer and the F layer were peeled from each other at an angle of 90 ° to the sample from the other end in the longitudinal direction at a drawing speed of 50 mm/min, and the maximum load (N/cm) applied at this time was measured.

The results are summarized in Table 1.

TABLE 1

In the laminate 1, since the surface of the metal foil is not treated with the silane coupling agent, high peel strength is obtained, and variation in peel strength between samples is small.

In contrast, in the laminate 2, the surface of the metal foil was treated with a silane coupling agent, and therefore not only was sufficient peel strength not obtained, but also variation in peel strength among samples was large. Further, since the laminate 3 uses the F polymer 2 having no oxygen-containing polar group, the peel strength is low despite the use of a metal foil whose surface is not treated with a silane coupling agent.

5-2 Peel Strength between Metal foil layer and F layer of laminate (2 thereof)

5-2-1 initial peel strength between metal foil layer and F layer of laminate

2 stacks 4 were stacked with the F layers in contact with each other, and vacuum-pressed at 340 ℃ for 20 minutes to obtain samples. For this sample, a metal foil layer etched to have a width of 3.2mm was peeled at an angle of 90 ℃ in accordance with IPC-TM650-2.4.9.E method dA, and the peel strength was measured. The peel strength of each of the prepared samples was also measured for laminates 5 to 7 in the same manner as for laminate 4.

5-2-2. post-heating peel strength between metal foil layer and F layer of laminate

Each sample prepared in 5-2-1 was put into a furnace at 150 ℃ and heated, and after 1000 hours, the peel strength was measured in the same manner as in 5-2-1.

The retention rate (%) was determined according to the following calculation formula.

Retention (%) - (peel strength after heating)/(initial peel strength) × 100

The results are summarized in Table 2.

TABLE 2

5-3. measurement of Transmission loss

A sample circuit of a microstrip line is formed using the laminated body 41. The line width of the signal layer is 120 mu m, the line length is 50mm, and the back surface is a solid ground layer. The sample circuit was clamped with a UTF (Universal Test Fixture) and the transmission loss at 40GHz was measured using a network analyzer. The transmission loss was also measured for each of the laminate 51 and the laminate 61 in the same manner as for the laminate 41.

The results are summarized in Table 3.

TABLE 3

5-4 Peel Strength between prepreg layer and F layer of composite laminate (3 thereof)

The composite laminated body 8 was cut into a rectangular shape (length 100mm, width 10mm) to prepare a sample. Thereafter, one end of each sample in the longitudinal direction was fixed at a position of 50mm, and the prepreg layer and the F layer were peeled from each other at 90 ° to the sample from the other end in the longitudinal direction at a stretching speed of 50 mm/min, and the maximum load (N/cm) applied at this time was measured. The peel strength of the obtained samples was also measured for each of the composite laminates 9 to 13 in the same manner as for the composite laminate 8, and evaluated according to the following criteria.

[ evaluation standards ]

Very good: 15N/cm or more

Good: 10N/cm or more and less than 15N/cm

Δ: 5N/cm or more and less than 10N/cm

X: less than 5N/cm

The results are summarized in Table 4.

TABLE 4

Number of composite laminated body

8

9

10

11

12

13

Metal foil

Metal foil 7

Metal foil 6

Metal foil 7

Metal foil 8

Metal foil 7

Ten point surface roughness [ mu m ]]

1.2

0.2

1.2

7.7

1.2

Dispersion liquid

Dispersion 4

Dispersion 5

A

Sheet

A

Sheet 1

Sheet 2

Peel strength

◎

Δ

○

×

○

Δ

6. Production of composite laminate having solder mask layer

(example 14)

In the same manner as in example 8, the F layer of the laminate 8 and the prepreg 1 were laminated and thermocompression bonded. Thereafter, the metal foil layer was completely removed with an acid solution, and the contact surface (exposed surface) thereof was treated with a soft etchant ("gliberte GB-4300" manufactured by the four chemical industry corporation ()). In addition, the soft etchant is an aqueous solution containing sulfuric acid and hydrogen peroxide. Then, a solder resist ("PSR-4000 LD 1K" manufactured by Sun-ink GmbH (TaiYANG インキ Co.) was applied directly (without polishing) to the exposed surface thus treated by a screen printing method so that the thickness thereof became 30 μm.

Thereafter, the solder resist was dried at 80 ℃ for 3 minutes and exposed to 400mJ/cm²After the UV light, the substrate was immersed in a 1 mass% aqueous solution of sodium carbonate for 60 seconds to develop an image. Thereafter, the solder resist was post-cured at 150 ℃ for 60 minutes, and further exposed to 1000mJ/cm²The solder mask layer is formed by the UV light, and a composite laminate 14 in which the exposed F layer and the solder mask layer are laminated is obtained.

(example 15)

A composite laminate 15 was obtained in the same manner as in example 14, except that the metal foil 8 was used.

(example 16)

A composite laminate 16 was obtained in the same manner as in example 14, except that the contact surface (exposed surface) of the F layer was treated with a soft etchant, and a solder resist was applied after buff polishing.

7. Evaluation of adhesion

For each of the laminates 14 to 16, the following laminates were each prepared by K5600-5-6: the adhesion between the F layer and the solder resist layer was evaluated by a 100-grid cross-cut test defined in 1999(ISO 2409: 1992), and as a result, the cut of the composite laminated body 14 was completely smooth, and no peeling occurred in all grids.

In the composite laminate 15, a large peeling occurs along the cut.

In the composite laminate 16, some delamination was found along the cuts and at the score intersections.

Possibility of industrial utilization

The laminate of the present invention and the composite laminate produced by the present invention have excellent electrical characteristics and adhesiveness, and have a polymer layer firmly fixed to a metal foil layer, and therefore can be processed and used as an antenna component, a printed wiring board, an insulating layer of a power semiconductor, an aircraft component, an automobile component, and the like.

Claims

1. A laminate which is a laminate having a metal foil layer and a polymer layer provided in direct contact on a surface of the metal foil layer, the polymer layer comprising a melt viscosity at 380 ℃ of 1 x 10²～1×10⁶And Pa s, wherein the metal foil layer is a metal foil layer having no silicon atom on the surface, or a metal foil layer having a nickel atom content of 0.03 to 0.25 mass% detected by fluorescent X-ray analysis of the surface.

2. The laminate according to claim 1, wherein the metal foil layer comprises a substrate layer and a roughened layer comprising metal particles and having the surface.

3. The laminate according to claim 1 or 2, wherein the metal foil layer comprises a base material layer and a roughening treatment layer having the surface, the roughening treatment layer being composed of metal particles, and the metal particles are formed of copper, nickel, phosphorus, tungsten, arsenic, molybdenum, chromium, cobalt, zinc, or an alloy containing 1 or more kinds thereof.

4. The laminate according to any one of claims 1 to 3, wherein the metal foil layer comprises a substrate layer and a roughened layer having the surface, the roughened layer being composed of metal particles, and the metal particles comprise acicular metal particles.

5. The laminate according to any one of claims 1 to 4, wherein the surface of the metal foil layer has a ten-point average roughness of 0.1 μm or more.

6. The laminate according to any one of claims 1 to 5, wherein the tetrafluoroethylene polymer is a tetrafluoroethylene polymer comprising a perfluoro (alkyl vinyl ether) -based unit, or a polytetrafluoroethylene having a number average molecular weight of 20 ten thousand or less.

7. The laminate according to any one of claims 1 to 6, wherein the tetrafluoroethylene polymer is a tetrafluoroethylene polymer having an oxygen-containing polar group and containing a perfluoro (alkyl vinyl ether) -based unit, or a tetrafluoroethylene polymer having no oxygen-containing polar group and containing a perfluoro (alkyl vinyl ether) -based unit in an amount of 2.0 to 5.0 mol% based on the total units.

8. The laminate according to any one of claims 1 to 7, wherein the polymer layer has a peel strength of 10N/cm or more with respect to the metal foil layer.

9. A method for producing a laminate, which comprises forming a polymer layer on a surface of a metal foil in direct contact without treating the surface of the metal foil with a silane coupling agent, to obtain a laminate having the polymer layer provided in direct contact on a surface of a metal foil layer composed of the metal foil, the polymer layer containing a silane coupling agent at 380 ℃Melt viscosity of 1X 10²～1×10⁶Pa · s tetrafluoroethylene polymer.

10. A method for producing a laminate, which comprises forming a polymer layer in direct contact with the surface of a metal foil having a nickel atom content of 0.03 to 0.25 mass% detected in fluorescent X-ray analysis, and obtaining a laminate having the polymer layer provided in direct contact with the surface of a metal foil layer made of the metal foil, wherein the polymer layer has a melt viscosity of 1X 10 at 380 ℃²～1×10⁶Pa · s tetrafluoroethylene polymer.

11. A method for producing a composite laminate, comprising removing at least a part of a metal foil layer of a laminate comprising the metal foil layer having a surface with a ten-point average roughness of 0.1 [ mu ] m or more and a polymer layer provided on the surface, and bonding the exposed polymer layer to a prepreg to obtain a composite laminate in which at least the polymer layer and the prepreg layer are laminated, wherein the polymer layer comprises a polymer having a melt viscosity of 1 x 10 at 380 ℃²～1×10⁶Pa · s tetrafluoroethylene polymer.

12. The production method according to claim 11, wherein the exposed surface of the polymer layer is bonded to the prepreg without subjecting it to hydrophilization treatment.

13. A method for producing a composite laminate, comprising removing at least a part of a metal foil layer of a laminate having the metal foil layer with a surface having a ten-point average roughness of 0.1 [ mu ] m or more and a polymer layer provided on the surface, coating a solder resist on the exposed polymer layer, and curing the coating to form a solder mask layer, thereby obtaining a composite laminate in which at least the polymer layer and the solder mask layer are laminated, wherein the polymer layer comprises a polymer having a melt viscosity of 1 x 10 at 380 ℃²～1×10⁶Pa · s tetrafluoroethylene polymer.

14. The manufacturing method according to claim 13, wherein the surface of the exposed polymer layer is treated with an acid solution, and thus a solder resist is directly applied and cured to form a solder mask layer.

15. A method for producing a polymer film, comprising removing a metal foil layer of a laminate having the metal foil layer with a surface having a ten-point average roughness of 0.1 [ mu ] m or more and a polymer layer provided on the surface, wherein the polymer layer containing a polymer having a melt viscosity of 1 x 10 at 380 ℃ is left as a polymer film²～1×10⁶Pa · s tetrafluoroethylene polymer.