Composition, film, laminate, and method for manufacturing laminate

Abstract

A composition containing a tetrafluoroethylene-based polymer having a carbonyl group-containing group with a melting temperature of 200 to 320°C and a transition metal content of greater than 0.05 ppm and 1 ppm or less as measured by a ashing method, for forming a polymer layer on the surface of a metal substrate layer.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a composition, a film, a laminate, and a method for manufacturing a laminate. BACKGROUND

[0002] Teflon (PTFE) and the like tetrafluoroethylene-based polymers have excellent properties such as chemical resistance, water / oil repellency, heat resistance, and electrical properties, and various uses thereof are known. In recent years, tetrafluoroethylene-based polymers are used in the manufacture of metal-clad laminates that can be processed into printed boards having excellent electrical properties and heat resistance.

[0003] For example, International Publication No. 2016 / 17801 and International Publication No. 2018 / 016644 describe metal-clad laminates having a metal substrate layer and a polymer layer formed using a composition containing a tetrafluoroethylene-based polymer having a carbonyl group-containing group with a melting temperature of 200 to 320°C. SUMMARY

[0004] PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] However, the above-described metal-clad laminates require various properties depending on their uses.

[0006] In recent years, there is a tendency to further improve the adhesion between the metal substrate layer and the polymer layer of the laminate, the electrical properties (dielectric constant and dielectric loss tangent) of the polymer layer, and the like.

[0007] One embodiment of the present disclosure aims to provide a composition, a film, a laminate, and a method for manufacturing a laminate that can form a polymer layer having excellent adhesion and electrical properties on the surface of a metal substrate layer.

[0008] TECHNICAL SOLUTION

[0009] The technical means for solving the above-described technical problem include the following modes.

[0010] <1> A composition containing a tetrafluoroethylene-based polymer having a carbonyl group-containing group with a melting temperature of 200 to 320°C and having a transition metal content of more than 0.05 ppm and 1 ppm or less as measured by the ashing method, which is used for forming a polymer layer on the surface of a metal substrate layer.

[0011] <2> The composition according to the above <1>, wherein the transition metal is one or more metals selected from the group consisting of Fe, Co, Ni, Cu, Cr, Au, and Ag.

[0012] <3> The composition according to the above <1> or <2>, further containing a liquid dispersion medium.

[0013] The composition according to any one of <1> to <5> above, wherein the liquid dispersion medium is a polar solvent.

[0014] The composition according to <3> above, wherein the liquid dispersion medium is a non-aqueous polar solvent, and the water content of the composition is 100 ppm or more.

[0015] The composition according to any one of <1> to <5> above, wherein the tetrafluoroethylene-based polymer has a particle shape, and the average particle diameter is more than 1 μm.

[0016] The composition according to any one of <1> to <6> above, wherein the content of the tetrafluoroethylene-based polymer is 20 mass% or more.

[0017] The composition according to any one of <1> to <7> above, which further contains a non-metallic inorganic filler.

[0018] The composition according to <8> above, wherein the ratio of the content of the tetrafluoroethylene-based polymer to the content of the inorganic filler is 1 or less on a mass basis.

[0019] A film containing a tetrafluoroethylene-based polymer having a carbonyl group-containing group with a melting temperature of 200 to 320°C and a transition metal content of more than 0.05 ppm and 1 ppm or less as measured by the ashing method, which is used for laminating on the surface of a metal substrate layer.

[0020] A laminate having a metal substrate layer and a polymer layer containing a tetrafluoroethylene-based polymer having a carbonyl group-containing group with a melting temperature of 200 to 320°C and a transition metal content of more than 0.05 ppm and 1 ppm or less as measured by the ashing method.

[0021] The laminate according to <11> above, wherein the maximum height roughness (Rz) of the surface of the metal substrate layer on which the polymer layer is formed is 2 μm or less.

[0022] A method for producing a laminate by disposing a composition containing a tetrafluoroethylene-based polymer having a carbonyl group-containing group with a melting temperature of 200 to 320°C and a transition metal content of more than 0.05 ppm and 1 ppm or less as measured by the ashing method on at least one surface of a metal substrate layer, and heating to form a polymer layer on the surface of the metal substrate layer, thereby obtaining a laminate having a metal substrate layer and a polymer layer on at least one surface of the metal substrate layer.

[0023] Effects of the Invention

[0024] According to the embodiment of the present disclosure, it is possible to provide a composition, a film, a laminate, and a laminate manufacturing method that can form a polymer layer having excellent adhesion and electrical properties on the surface of a metal substrate layer. DETAILED DESCRIPTION

[0025] Hereinafter, the embodiments of the present disclosure will be described in detail. However, the present disclosure is not limited to the following embodiments. In the following embodiments, unless otherwise specifically stated, the constituent elements (including element steps, etc.) are not necessarily essential. The numerical values and ranges thereof also similarly do not limit the embodiments of the present disclosure.

[0026] In the present disclosure, the numerical range represented by “~” includes the numerical values recited before and after “~” as the minimum value and the maximum value, respectively.

[0027] In the present disclosure, each component can include a plurality of corresponding substances. In the case where a plurality of substances corresponding to each component is present in the composition, unless otherwise specifically stated, the content ratio or the content of each component refers to the total content ratio or the total amount of the plurality of substances present in the composition.

[0028] In the present disclosure, the particles corresponding to each component can include a plurality of them. In the case where a plurality of particles corresponding to each component is present in the composition, unless otherwise specifically stated, the particle diameter of each component refers to the value of the mixture of the plurality of particles present in the composition.

[0029] In the present disclosure, the term “lamination” means that layers are laminated, and can be two or more layers combined together, or two or more layers that can be disassembled.

[0030] In the present disclosure, the “transition metal content” is measured by ashing method. As the ashing method, it is described in International Publication No. 94 / 28394. Specifically, the measurement object is accurately weighed in the range of 2 to 6 mg, heated at 1100°C for 180 seconds to ash in a cuvette, and analyzed with an atomic absorption spectrophotometer. As the cuvette, a graphite cuvette can be used. As the atomic absorption spectrophotometer, a polarized Zeeman atomic absorption spectrophotometer (Z-8100) manufactured by Hitachi, Ltd. or the like can be used.

[0031] In the present disclosure, the “moisture content” is measured by Karl Fischer method. As the Karl Fischer method, specifically, it is by the method according to JIS K 0068 (2001) described in Japanese Patent Application Publication No. 2017-066327. As the measurement device, a Karl Fischer moisture meter (MCU-610) manufactured by Kyoto Electronics Manufacturing Co., Ltd. or the like can be used.

[0032] In the present disclosure, the “maximum height roughness (Rz)” is measured in accordance with JIS B 0601 (2013).

[0033] In the present disclosure, the "average particle diameter (D50)" is the particle diameter at which the cumulative volume of particles is 50% as measured by a laser diffraction / scattering method. That is, the particle size distribution is measured by a laser diffraction / scattering method, and the cumulative curve is obtained with the total volume of the particle groups being 100%, and the particle diameter at the point at which the cumulative volume reaches 50% on the cumulative curve is measured.

[0034] The D50 of the particles is obtained by analyzing the particles dispersed in water by a laser diffraction / scattering method using a laser diffraction / scattering particle size distribution measuring device (for example, a LA-920 measuring device manufactured by HORIBA, Ltd.).

[0035] In the present disclosure, the "melting temperature" refers to the temperature corresponding to the maximum value of the melting peak of a polymer as measured by a differential scanning calorimetry (DSC) method.

[0036] In the present disclosure, the "weight average molecular weight" is obtained by polystyrene conversion using gel permeation chromatography (GPC).

[0037] In the present disclosure, the "glass transition temperature (Tg)" is a value measured by analyzing a polymer using a dynamic viscoelasticity measurement (DMA) method.

[0038] In the present disclosure, a "polymer" is a compound obtained by polymerization of a monomer. That is, a "polymer" has a plurality of units based on a monomer.

[0039] In the present disclosure, a "unit" in a polymer refers to a group of atoms based on a monomer formed by polymerization of the monomer. The unit can be a unit directly formed by a polymerization reaction, or a unit in which a part of the unit is converted to another structure by processing the polymer.

[0040] The composition of the present disclosure (hereinafter also referred to as "F composition") is used to form an F polymer layer (hereinafter also referred to as "F polymer layer") on the surface of a metal substrate layer, and contains a tetrafluoroethylene-based polymer having a carbonyl group-containing group (hereinafter also referred to as "F polymer") having a melting temperature of 200 to 320°C, and has a transition metal content of greater than 0.05 ppm and 1 ppm or less as measured by an ashing method. From the viewpoint of adhesion to the metal substrate layer, the lower limit of the transition metal content is preferably 0.06 ppm, and more preferably 0.10 ppm. In addition, from the viewpoint of the electrical properties of the formed polymer layer, the upper limit of the transition metal content is preferably 0.75 ppm, and more preferably 0.50 ppm. The transition metal content can be adjusted by adjusting the polymerization initiator used at the time of synthesis of the F polymer, selecting the raw materials such as the polymerization solvent, adjusting the constituent material of the device such as the stirrer used for the production of the F composition, adding or removing a transition metal component to or from the F composition used for the production of the F polymer, and the like.

[0041] By using the F composition, it is possible to form an F polymer layer having excellent adhesion and electrical properties on the surface of the metal substrate layer. The mechanism of action is not clear, but it is presumed as follows. The F composition contains a transition metal at a content rate of more than 0.05 ppm in addition to the F polymer having a carbonyl group. It is presumed that in the F polymer layer containing the F polymer, the transition metal interacts with the carbonyl group of the F polymer, and the affinity of the metal component to the portion resulting from the interaction is enhanced, and thus the adhesion of the metal substrate layer to the F polymer layer is enhanced. In addition, it is presumed that by making the content rate of the transition metal in the F composition be 1 ppm or less, the decrease in electrical properties due to the transition metal can be suppressed.

[0042] The F composition contains an F polymer. One kind of F polymer can be used, or two or more kinds of F polymers can be used. The F polymer is a polymer containing a unit based on tetrafluoroethylene (hereinafter also referred to as "TFE") (hereinafter also referred to as "TFE unit"). From the viewpoint of advantageously exhibiting the properties brought about by the TFE unit, the content rate of the TFE unit in the F polymer is preferably 50 mol% or more, more preferably 90 mol% or more, with respect to the total units in the F polymer. The above content rate can be 99 mol% or less, or 98 mol% or less.

[0043] From the viewpoint of adhesion to the metal substrate layer, the carboxyl group is preferably one or more selected from the group consisting of a carboxyl group, an alkoxycarbonyl group, an amide group, an isocyanate group, a maleimide group, a carbamate group (-OC(O)NH2), an acid anhydride residue (-C(O)OC(O)-), an imide residue (-C(O)NHC(O)- and the like), and a carbonate group (-OC(O)O-), and more preferably one or more selected from the group consisting of an acid anhydride group, a carboxyl group, and a maleimide group.

[0044] The number of carbonyl groups in the F polymer is preferably 10 or more, more preferably 50 or more, and further preferably 100 or more, per 1 x 10 6 main chain carbons, and is more preferably 5000 or less, and further preferably 3000 or less, per 1 x 10 6 main chain carbons. In addition, the number of carbonyl groups can be quantified according to the method described in International Publication No. 2020 / 145133 or the composition of the polymer. Furthermore, in the present specification, the F polymer having no carbonyl group means an F polymer having a number of carbonyl groups of less than 10 per 1 x 10 6 main chain carbons.

[0045] The carbonyl group-containing group can be contained in a monomer-based unit in the F polymer, or can be contained in a terminal group of the F polymer main chain, preferably the former. As the latter, tetrafluoroethylene-based polymers having a carbonyl group-containing group as a terminal group derived from a polymerization initiator, a chain transfer agent, or the like, polymers obtained by subjecting a tetrafluoroethylene-based polymer to plasma treatment or ionizing radiation treatment, and the like can be exemplified. As the monomer having a carbonyl group-containing group, itaconic anhydride, citraconic anhydride, and 5-norbornene-2,3-dicarboxylic anhydride (hereinafter also referred to as "NAH") are preferable, and NAH is more preferable from the viewpoint of adhesion of the F polymer layer to the metal substrate layer.

[0046] The F polymer is preferably polytetrafluoroethylene (PTFE), a polymer containing a TFE unit and an ethylene-based unit (ETFE), a polymer containing a TFE unit and a propylene-based unit, a polymer containing a TFE unit and a perfluoro(alkyl vinyl ether)-based (PAVE) unit (PAVE unit) (PFA), or a polymer containing a TFE unit and a hexafluoropropylene-based unit (FEP), more preferably a PFA or FEP having a carbonyl group-containing group, and further preferably a PFA having a carbonyl group-containing group. These polymers can further contain a unit based on another comonomer.

[0047] The F polymer is preferably a polymer having a carbonyl group-containing group containing a TFE unit and a PAVE unit, more preferably a polymer containing a TFE unit, a PAVE unit, and a unit based on a monomer having a carbonyl group-containing group, and further preferably a polymer containing a TFE unit, a PAVE unit, and a unit based on a monomer having a carbonyl group-containing group and sequentially containing 90 to 99 mol%, 0.99 to 9.97 mol%, and 0.01 to 3 mol% of these units with respect to the total units. As the PAVE, perfluoro(propyl vinyl ether) (PPVE) is preferable. As a specific example of the F polymer, the polymer described in International Publication No. 2018 / 016644 can be exemplified.

[0048] The F polymer has a melting temperature of 200 to 320°C, preferably 250 to 320°C, and more preferably 280 to 320°C. In the case where an F polymer having such a high melting temperature is used to form an F polymer layer on the surface of a metal substrate layer, the F polymer layer is sometimes formed before the F polymer is sufficiently filled, the F polymer present at the interface with the metal substrate layer is reduced, and the adhesion of the F polymer layer to the metal substrate layer is decreased. In the present disclosure, however, the interaction of the transition metal with the F polymer improves the interlayer adhesion, and thus the adhesion is easily improved even when the F polymer having such a high melting temperature is used.

[0049] From the same viewpoint, the F polymer preferably has a glass transition temperature of 70 to 150°C.

[0050] The fluorine content of the F polymer is preferably 70 to 76 mass%. In addition, the fluorine content is obtained from the composition of the polymer. The F polymer having a high fluorine content is particularly excellent in electrical properties, but has a tendency to have extremely low affinity with other materials and low adhesion of the F polymer layer to the metal substrate layer, but according to the present disclosure, the adhesion can be improved by the above-described mechanism of action.

[0051] From the viewpoints of electrical properties (low dielectric constant, etc.), heat resistance, and the like, the F polymer is preferably in a particulate shape. From the viewpoints of the handleability of the F composition and the surface smoothness and the like of the F polymer layer formed, the average particle diameter (D50) of the particulate F polymer (hereinafter also referred to as "F particles") is preferably greater than 1 μm, more preferably 1.5 μm or greater. The D50 of the F particles is preferably 5 mm or less, more preferably 1 mm or less, further preferably 100 μm or less, and particularly preferably less than 10 μm. Furthermore, by making the average particle diameter of the F particles within the above-described numerical range, the surface area of the F particles becomes large, the interaction with the transition metal component is promoted, and there is a tendency to be able to further improve the adhesion of the F polymer layer formed from the composition to the metal substrate layer.

[0052] From the viewpoints of the adhesion, smoothness, electrical properties, heat resistance, and the like of the F polymer layer to the metal substrate layer, the content ratio of the F polymer with respect to the total mass of the F composition is preferably 20 mass% or greater, more preferably 25 mass% or greater, and further preferably 30 mass% or greater. In addition, the content ratio of the F polymer is preferably 70 mass% or less, more preferably 55 mass% or less, and further preferably 40 mass% or less. In the case where the F polymer layer is formed on the surface of the metal substrate layer using a composition in which the content ratio of the F polymer is 20 mass% or greater, the F polymer layer is sometimes formed without the F polymer being sufficiently filled, the F polymer present at the interface with the metal substrate layer is reduced, and the adhesion of the F polymer layer to the metal substrate layer is decreased. In the present disclosure, however, the interaction of the transition metal with the F polymer improves the interlayer adhesion, and thus even if a composition in which the content ratio of the F polymer is 20 mass% or greater is used, sufficient adhesion can be easily exhibited. In addition, since the content ratio of the F polymer in the composition can be increased, the F polymer layer having a thickness can be formed at one time.

[0053] The kind of the transition metal contained in the F composition is not particularly limited, and a transition metal conventionally known can be used. From the viewpoints of the adhesion of the F polymer layer to the metal substrate layer and the electrical properties, one or more metals selected from the group consisting of Fe, Co, Ni, Cu, Cr, Au, and Ag is / are preferred, and one or more metals selected from the group consisting of Fe, Ni, and Cr is / are more preferred. In addition, the transition metal contained in the F composition can be contained in any one of the states of an elemental atom, a covalent compound such as an oxide, a nitride, a complex, a carbonate, a sulfate, a nitrate, and an ionic compound.

[0054] The F composition can further contain a liquid dispersion medium.

[0055] From the viewpoint of more easily exhibiting the above-described mechanism of action, the liquid dispersion medium is preferably a polar solvent. The polar solvent can be water, or a non-aqueous polar solvent such as an amide, a ketone, an alcohol, an ester, or the like.

[0056] As the non-aqueous polar solvent, an amide, a ketone, a glycol, a glycol ether, a glycol acetate can be exemplified. Among these, an amide, a ketone, N-methyl-2-pyrrolidone, γ-butyrolactone, cyclohexanone, or cyclopentanone, a glycol monoalkyl ether, a glycol monof aryl ether, a glycol monoalkyl ether acetate, a glycol monof aryl ether acetate, or the like can be exemplified.

[0057] Further, in the case where a non-aqueous polar solvent is used as the liquid dispersion medium, from the viewpoint of improving the interaction of the F polymer with the transition metal and enhancing the adhesion of the F polymer layer to the metal substrate layer, the water content of the F composition is preferably 100 ppm or more, more preferably 500 ppm or more, and further preferably 1000 ppm or more. The upper limit of the water content is not particularly limited, and can be 100000 ppm. The content of the liquid dispersion medium with respect to the total mass of the F composition is not particularly limited, and can be 30 to 80 mass%.

[0058] The F composition contains a non-metallic inorganic filler, whereby the F polymer layer can also be imparted with the properties of the non-metallic inorganic filler. For example, the linear expansion coefficient of the F polymer layer can be reduced, and the adhesion to the metal substrate layer can be enhanced. As the non-metallic inorganic filler, a nitride filler, an inorganic oxide filler can be exemplified, and one or more selected from the group consisting of a boron nitride filler, a beryllium oxide (an oxide of beryllium), and a silicon oxide filler is preferable.

[0059] The shape of the non-metallic inorganic filler is not particularly limited, and can be particulate, or non-particulate such as fibrous, scaly, or the like. From the viewpoint of the dispersibility of the F polymer layer, particulate is preferable. From the viewpoint of the dispersibility of the F polymer layer and the like, the average particle diameter (D50) of the particulate inorganic filler is preferably 0.01 μm to 20 μm, and more preferably 0.1 μm to 10 μm. Further, the non-metallic inorganic filler can have a fine structure. Further, by making the average particle diameter of the non-metallic inorganic filler within the above numerical range, the non-metallic inorganic filler can be dispersed well in the F polymer layer formed from the F composition, the non-metallic inorganic filler present on the surface can be reduced, and the adhesion to the metal substrate layer can be enhanced. At least a part of the surface of the non-metallic inorganic filler can be subjected to silane coupling agent coating treatment (surface treatment).

[0060] From the viewpoint of the adhesion of the F polymer layer to the metal substrate layer, the content of the non-metallic inorganic filler is preferably 20% by mass or more, more preferably 25% by mass or more, and further preferably 30% by mass or more, relative to the total mass of the F composition. In addition, the content of the non-metallic inorganic filler is preferably 70% by mass or less, more preferably 60% by mass or less, and further preferably 50% by mass or less.

[0061] The ratio of the content of the tetrafluoroethylene-based polymer to the content of the non-metallic inorganic filler (content of tetrafluoroethylene-based polymer / content of non-metallic inorganic filler) is preferably 1 or less on a mass basis. In addition, the ratio is preferably 0.1 or more. In the case where the F polymer layer is formed from the F composition containing the non-metallic inorganic filler, the F polymer layer is sometimes formed without the F polymer being sufficiently filled, the F polymer present at the interface with the metal substrate layer is reduced, the adhesion of the F polymer layer to the metal substrate layer is decreased, or the non-metallic inorganic filler is sometimes exposed at the interface of the F polymer layer, the adhesion of the F polymer layer to the metal substrate layer is decreased. In the present disclosure, however, the adhesion is easily improved even if the F composition is used, due to the interaction of the transition metal with the F polymer.

[0062] The F composition can contain a polymer other than the F polymer (hereinafter also referred to as "A polymer"). One kind of A polymer can be used, or two or more kinds of A polymer can be used. As the A polymer, a polyamide resin (hereinafter also referred to as "PA"), a polyimide resin (hereinafter also referred to as "PI"), a maleimide resin (hereinafter also referred to as "MI"), a polyamide-imide resin (hereinafter also referred to as PAI), a polyetherimide resin, a polysulfone resin, a polyethersulfone resin, a polyetherketone resin, a polyether ether ketone resin, a polyether ketone ketone resin, a polyolefin resin, a polyacetal resin, a polycarbonate resin, a polyester resin, a polyphenylene sulfide resin, a polyphenylene ether resin, a poly(meth)acrylate resin, a fluorine resin, or the like can be exemplified. Among the above, from the viewpoint of the affinity with the F polymer, PI, PAI, and MI are preferred.

[0063] From the viewpoint of the affinity with the F polymer, the A polymer preferably has a carbonyl group-containing group. The carbonyl group-containing group is as described above, and will not be described here. The number of carbonyl group-containing groups in the A polymer is preferably 10 to 5000, and more preferably 100 to 3000, per 1 x 10 6 The position of the carbonyl group-containing group is not particularly limited, and is preferably contained in at least one of the side chain and the terminal group of the main chain. In addition, from the viewpoint of improving the UV processability, the A polymer can have an aromatic group. The weight average molecular weight of the A polymer is preferably 10,000 to 1,000,000.

[0064] The content ratio of the A polymer with respect to the total mass of the F polymer and the A polymer is preferably 1 to 25% by mass, more preferably 2 to 20% by mass, and further preferably 3 to 15% by mass.

[0065] In addition to the above-mentioned components, the F composition can further contain, within a range not impairing the effects, a surfactant, a thixotropy imparting agent, a pH adjustor, a pH buffer, a viscosity adjustor, an antifoaming agent, a silane coupling agent, a dehydrating agent, a plasticizer, a weathering agent, an antioxidant, a heat stabilizer, a lubricant, an antistatic agent, a whitening agent, a coloring agent, a conductive agent, a mold release agent, a surface treatment agent, a flame retardant, various organic fillers, and other components.

[0066] The film of the present disclosure (hereinafter also referred to as "F film") is used for lamination on the surface of a metal substrate layer, contains an F polymer, and has a transition metal content of greater than 0.05 ppm and 1 ppm or less as measured by the ashing method. The preferred modes and content ratios of the F polymer, the preferred numerical ranges of the transition metal content, and the like are the same as those of the F composition, and thus will not be described here. The F composition can contain a non-metallic inorganic filler, an A polymer, other components, and the like. The preferred modes and content ratios of the inorganic filler and the A polymer, and the details of the other components and the like are the same as those of the F composition, and thus will not be described here.

[0067] The thickness of the F film is preferably 100 μm or less, more preferably 50 μm or less, and further preferably 25 μm or less. The lower limit of the thickness of the F film is not particularly limited, and can be 1 μm or more. By setting the thickness of the F film within the above numerical range, the F particles, the A particles, the inorganic filler, and the like can be dispersed well within the F film, the proportion of the F particles, the A particles, and the inorganic filler present on the surface of the F film can be reduced, and the adhesion of the F film to the metal substrate layer when the F film becomes a later-described laminate can be improved.

[0068] The F film can be produced by extrusion molding or the like. The production method of the F film is not limited thereto.

[0069] The laminate of the present disclosure (hereinafter also referred to as "F laminate") has a metal substrate layer and an F polymer layer containing an F polymer and having a transition metal content of greater than 0.05 ppm and 1 ppm or less as measured by the ashing method.

[0070] The F laminate can have two or more F polymer layers, and for example, a structure of F polymer layer / metal substrate layer / F polymer layer can be exemplified. In addition, the F laminate can have two or more metal substrate layers, and a structure of metal substrate layer / F polymer layer / metal substrate layer can be exemplified.

[0071] The kind of the metal base layer is not particularly limited, and as a metal constituting the metal base layer, copper, copper alloy, stainless steel, nickel, nickel alloy (including 42 alloy), aluminum, aluminum alloy, titanium, titanium alloy, and the like can be exemplified. The metal base layer is preferably constituted by a metal foil such as a rolled copper foil or an electrolytic copper foil. The surface of the metal foil can be subjected to rust-proof treatment (oxide film such as chromate, etc.), or can be subjected to roughening treatment. As the metal foil, a carrier-attached metal foil constituted by a carrier copper foil (thickness: 10 to 35 μm) and an extremely thin copper foil (thickness: 2 to 5 μm) laminated on the surface of the carrier copper foil via a release layer can be used. The surface of the metal base layer can be treated with a silane coupling agent. In this case, the entire surface of the metal base layer can be treated with the silane coupling agent, or a part of the surface of the metal base layer can be treated with the silane coupling agent.

[0072] The thickness of the metal base layer is preferably 2 to 40 μm, and more preferably 10 to 35 μm. From the viewpoint of obtaining a printed wiring board or the like having low transmission loss from the composition of the present disclosure, the maximum height roughness (Rz) of the surface of the metal base layer on which the F polymer layer is formed is preferably 2 μm or less, and more preferably 1 μm or less. Generally, in the case where the maximum height roughness (Rz) of the surface of the metal base layer on which the F polymer layer is formed is 2 μm or less, the adhesion to the F polymer layer tends to decrease. In the present disclosure, however, the interaction of the transition metal and the F polymer improves the interlayer adhesion, and the maximum height roughness (Rz) of the surface of the metal base layer on which the F polymer layer is formed is sufficient even if it is 2 μm or less. The lower limit of the maximum height roughness (Rz) is not particularly limited, and can be 0.01 μm or more.

[0073] The F laminate has an F polymer layer containing an F polymer and having a transition metal content of more than 0.05 ppm and 1 ppm or less as measured by the ashing method. The preferable modes and the preferable numerical ranges of the content of the F polymer, the transition metal content, and the like are the same as those of the F composition, and thus will not be described here. The F polymer layer can contain a non-metallic inorganic filler, an A polymer, other components, and the like. The preferable modes and the contents of the inorganic filler and the A polymer, and the details of the other components and the like are the same as those of the F composition, and thus will not be described here. Further, the preferable numerical range of the thickness of the F polymer layer is the same as that of the F film, and thus will not be described here.

[0074] The F laminate can be manufactured by the manufacturing method of the laminate described later. The manufacturing method of the F laminate is not limited thereto.

[0075] The manufacturing method of the laminate of the present disclosure (hereinafter referred to as the F-laminate manufacturing method) includes disposing the F-composition containing the F-polymer and having a transition metal content of greater than 0.05 ppm and 1 ppm or less as measured by the ashing method on at least one surface of the metal substrate layer, and heating to form the F-polymer layer on the surface of the metal substrate layer, thereby obtaining the laminate having the metal substrate layer and the F-polymer layer on at least one surface of the metal substrate layer. The disposing and heating of the F-composition can be repeated, and it is preferable to repeat from the viewpoint of the smoothness of the F-polymer layer. In addition, the F-polymer layer can be formed on both surfaces of the metal substrate layer. In addition, the preferable mode of the F-composition has been described above, and thus will not be described here.

[0076] The method of disposing the F-composition on the metal substrate layer is not particularly limited, and can be performed by, for example, coating the F-composition. As the method of coating the F-composition on the metal substrate layer, the following methods can be listed: 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 kiss coating method, a bar coating method, a die coating method, a fountain Meyer bar coating method, and a slit die coating method.

[0077] In the case where the F-composition contains the liquid dispersion medium, the heating of the F-composition preferably includes drying for the purpose of evaporating the liquid dispersion medium at a temperature in a low temperature range. The temperature in the low temperature range is not particularly limited, and is preferably 80°C or higher and less than 180°C, and more preferably 120 to 170°C. The temperature of the drying range refers to the temperature of the atmosphere at the time of drying. The retention time is preferably 0.1 to 10 minutes, and more preferably 0.5 to 5 minutes. In the drying of the F-composition, the retention at the temperature in the drying range can be performed in one step, or can be performed in two or more steps at different temperatures. As the method of the retention at the temperature in the drying range, the following methods can be listed: a method using an oven, a method using a ventilated drying oven, a method of irradiating heat rays such as infrared rays, and the like. The atmosphere at the time of the retention at the temperature in the drying range can be any state under normal pressure or under reduced pressure. In addition, the above atmosphere can be any one of an oxidizing gas atmosphere, a reducing gas atmosphere, and an inert gas atmosphere.

[0078] The heating of the F composition preferably includes firing for the purpose of firing the F polymer or the like at a temperature in a firing range. The temperature in the firing range is preferably 250 to 400°C, and more preferably 300 to 380°C. The temperature in the firing range refers to the temperature of the atmosphere at the time of firing. The time of keeping at the temperature in the firing range is preferably 0.5 to 5 minutes, and more preferably 1 to 2 minutes. As the method of keeping at the temperature in the firing range, for example, a method using an oven, a method using a through-air drying oven, a method of irradiating a heat ray such as infrared rays, and the like can be exemplified. In the firing of the F composition, the keeping at the temperature in the firing range can be performed in one step, or can be performed in two or more steps at different temperatures. In order to improve the smoothness of the surface of the F polymer layer, pressure can be applied using a hot plate, a heated roll, or the like. As the method of heating, from the viewpoint of being able to perform firing in a short time and a far infrared ray furnace being relatively compact, a method of irradiating far infrared rays is preferred. The method of heating can also be a combination of infrared ray heating and hot air heating. From the viewpoint of promoting uniform fusion of the F polymer, the effective wavelength band of the far infrared rays is preferably 2 μm to 20 μm, and more preferably 3 μm to 7 μm.

[0079] The atmosphere in which the heating for the purpose of firing is performed can be any state under normal pressure or under reduced pressure. Furthermore, the atmosphere can be any one of an oxidizing gas atmosphere, a reducing gas atmosphere, and an inert gas atmosphere, and from the viewpoint of suppressing oxidation deterioration of each of the metal substrate layer and the F polymer layer, a reducing gas atmosphere or an inert gas atmosphere is preferred.

[0080] In the method of manufacturing the F laminate, a metal substrate layer can be further provided on the surface of the F polymer layer formed on one surface of the metal substrate layer. The method of forming the metal substrate layer is not particularly limited, and a method of thermally pressure-bonding the F polymer layer and the metal substrate layer, or the like can be exemplified.

[0081] The use of the F film and the F laminate described above is not particularly limited, and for example, can be used for the manufacture of a printed substrate layer. The printed substrate layer can be exemplified by a method of processing a conductor circuit (patterned circuit) into a prescribed pattern by etching or the like of the metal substrate layer of the F laminate, or a method of forming a patterned circuit by plating (a semi-additive process (SAP method), a modified semi-additive process (MSAP method), or the like) of the F film.

[0082] Example

[0083] Hereinafter, the embodiments of the present disclosure will be described in detail by way of examples, but the embodiments of the present disclosure are not limited thereto.

[0084] 1. Preparation of each component for manufacturing a laminate

[0085] [F polymer]

[0086] F Polymer A: Polymer composed of 97.9 mol%, 0.1 mol%, and 2.0 mol% of TFE units, NAH units, and PPVE units, respectively, per 1 x 10 6 Polymer having 1000 main chain carbons and a carbonyl group-containing unit (melting temperature: 300°C), particle form (D50: 2 μm)

[0087] F Polymer B: Polymer composed of 97.5 mol% and 2.5 mol% of TFE units and PPVE units, respectively, without a carbonyl group-containing unit (melting temperature: 300°C) (D50: 2.0 μm)

[0088] [liquid dispersion medium]

[0089] Liquid dispersion medium: N-methyl-2-pyrrolidone

[0090] [non-metallic inorganic filler]

[0091] Non-metallic inorganic filler: Silane coupling agent-treated particles, D50: 2 μm

[0092] [metal substrate layer]

[0093] Metal substrate layer: Copper foil, thickness 18 μm, maximum roughness (Rz) 0.1 μm

[0094] 2. Production of laminate

[0095] Example 1

[0096] F Polymer A 25 parts by mass, non-metallic inorganic filler 25 parts by mass were added to a liquid dispersion medium 50 parts by mass, and stirred with a stirrer to obtain a composition. The transition metal content in the composition was 0.1 ppm as measured by the ashing method. In addition, the water content of the composition was 1000 ppm.

[0097] The above composition was applied to the surface of the metal substrate layer, dried, and an F polymer layer having a thickness of 25 μm was formed to obtain a laminate.

[0098] Example 2

[0099] A composition and a laminate were produced in the same manner as in Example 1, except that F Polymer A was changed to F Polymer B.

[0100] Examples 3 to 5

[0101] A composition and a laminate were produced in the same manner as in Example 1, except that the transition metal content in the composition as measured by the ashing method was changed to the value shown in Table 1 (Examples 3 and 4). In addition, a composition and a laminate were produced in the same manner as in Example 1, except that the water content of the composition was changed to the value shown in Table 1 (Example 5).

[0102] 3. Evaluation

[0103] <<Peeling strength evaluation>>

[0104] In order to measure the peeling strength of the metal substrate layer and the F polymer layer of the laminate obtained in Examples 1 to 5, the laminate was cut into a size of 100 mm in length and 10 mm in width to prepare a test piece. The metal substrate layer and the F polymer layer were peeled from one end of the test piece to a position 50 mm apart. Then, using a tensile testing machine (manufactured by Orientec Corporation), a 90-degree peeling was performed at a tensile speed of 50 mm / min with the position 50 mm apart from one end of the test piece as the center, and the maximum load was measured as the peeling strength (N / 10 mm).

[0105] With the peeling strength of the laminate manufactured in Example 3 as a reference (100%), with respect to other laminates, cases where the peeling strength was shown to be higher than the reference by 10% or more were noted as "improved", cases where the peeling strength was shown to be lower than the reference by 10% or more were noted as "decreased", and cases where the peeling strength was shown to be within ±10% of the reference were noted as "equivalent", and the peeling strength was evaluated.

[0106] <<Adhesion state evaluation>>

[0107] In addition, after the laminates obtained in Examples 1 to 5 were embedded with an epoxy resin, cross-section processing was performed with a cross-section polisher, and the cross-section was observed with an SEM. The density of the F polymer in the vicinity of the interface between the metal substrate layer and the F polymer layer, and the interface between the non-metallic inorganic filler and the F polymer was evaluated by the size of the voids present in the vicinity of each interface.

[0108] With the voids of the laminate manufactured in Example 3 as a reference, with respect to other laminates, cases where there was a tendency to have smaller voids than the reference and the density of the F polymer was improved were noted as "improved", cases where there were larger voids than the reference and the density of the F polymer was decreased were noted as "decreased", and cases where there were voids of the same order as the reference and the density of the F polymer was the same were noted as "equivalent", and the adhesion state was evaluated.

[0109] <<Dielectric constant evaluation>>

[0110] The dielectric constant at a frequency of 2.5 GHz was obtained for the F polymer layer of the laminate obtained in Examples 1 to 4 by a split post dielectric resonator method (SPDR method). The equipment used for the dielectric constant measurement was a split post dielectric resonator of a nominal fundamental frequency of 2.5 GHz manufactured by QWED, a vector network analyzer E8361C manufactured by Keysight Technologies, and software for dielectric constant calculation, 85071E Option 300, manufactured by Keysight Technologies.

[0111] On the basis of the dielectric constant exhibited by the F polymer layer of the laminate manufactured in Example 3 (100%), the F polymer layer of the other laminates was evaluated as "optimized" if it exhibited a dielectric constant lower than the reference by 10% or more, as "decreased" if it exhibited a dielectric constant lower than the reference by 10% or more, and as "equivalent" if it exhibited a dielectric constant within ±10% of the reference.

[0112] [Table 1]

[0113]

[0114] The disclosure of Japanese Patent Application No. 2022-020651 filed on February 14, 2022, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards cited in this specification are incorporated by reference herein as if each individual document, patent application, or technical standard were specifically and individually indicated to be incorporated by reference.

Claims

1. A composition comprising a tetrafluoroethylene polymer having a carbonyl group having a melting temperature of 200-320°C, and having a transition metal content greater than 0.05 ppm and less than 1 ppm as determined by ashing, for use in forming a polymer layer on the surface of a metal substrate layer.

2. The composition of claim 1, wherein, The transition metal is one or more metals selected from Fe, Co, Ni, Cu, Cr, Au and Ag.

3. The composition according to claim 1 or 2, wherein, It further contains a liquid dispersion medium.

4. The composition of claim 3, wherein, The liquid dispersion medium is a polar solvent.

5. The composition of claim 3, wherein, The liquid dispersion medium is a non-aqueous polar solvent, and the water content of the composition is above 100 ppm.

6. The composition according to claim 1 or 2, wherein, The tetrafluoroethylene polymer is in the form of particles with an average particle size greater than 1 μm.

7. The composition according to claim 1 or 2, wherein, The content of the tetrafluoroethylene polymer is above 20% by mass.

8. The composition according to claim 1 or 2, wherein, It further contains non-metallic inorganic fillers.

9. The composition of claim 8, wherein, The ratio of the content of the tetrafluoroethylene polymer to the content of the inorganic filler is less than 1 by mass.

10. A membrane comprising a tetrafluoroethylene polymer having a carbonyl group having a melting temperature of 200–320°C, and having a transition metal content greater than 0.05 ppm and less than 1 ppm as determined by an ashing method, for use on the surface of a metal substrate layer.

11. A laminate comprising a metal substrate layer and a polymer layer, the polymer layer comprising a tetrafluoroethylene polymer having a carbonyl group having a melting temperature of 200–320°C, and wherein the transition metal content, as determined by an ashing method, is greater than 0.05 ppm and less than 1 ppm.

12. The laminate as claimed in claim 11, wherein, The maximum height roughness Rz of the surface of the metal substrate layer where the polymer layer is formed is less than 2 μm.

13. A method for manufacturing a laminate, wherein a composition comprising a tetrafluoroethylene polymer having a carbonyl group and having a melting temperature of 200 to 320°C and having a transition metal content greater than 0.05 ppm and less than 1 ppm as determined by an ashing method is disposed on at least one surface of a metal substrate layer, and a polymer layer is formed on the surface of the metal substrate layer by heating, thereby obtaining a laminate having a metal substrate layer and a polymer layer on at least one surface of the metal substrate layer.

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