TWI820138B - Method for manufacturing metal foil with resin and metal foil with resin - Google Patents

Abstract

The present invention provides an efficient manufacturing method of a resin-attached metal foil that has electrical properties and mechanical strength and is useful for manufacturing printed circuit boards. The resin-attached metal foil has high homogeneity containing a fluoropolymer and the resin-attached metal foil. The resin layer is durable and not easy to warp. A method of manufacturing a resin-attached metal foil, which is a method of manufacturing a resin-attached metal foil with a resin layer on the surface of the metal foil. The manufacturing method is as follows: A powder dispersion containing tetrafluoroethylene polymer powder and a solvent is coated on the surface of the metal foil. The temperature range of the tetrafluoroethylene polymer powder exhibiting a storage elastic modulus of 0.1 to 5.0 MPa is below 260°C. And the melting point exceeds 260℃, Keep the metal foil at a temperature within the aforementioned temperature zone, The tetrafluoroethylene polymer is further fired at a temperature exceeding the aforementioned temperature range to form a resin layer containing the tetrafluoroethylene polymer on the surface of the metal foil.

Description

Method for manufacturing metal foil with resin and metal foil with resin

The present invention relates to a method for manufacturing a resin-attached metal foil and a resin-attached metal foil.

Background of the invention The resin-attached metal foil having an insulating resin layer on the surface of the metal foil can be used as a printed circuit board by processing the metal foil such as etching. For printed circuit boards used to transmit high-frequency signals, excellent transmission characteristics are required. Therefore, in order to improve transmission characteristics, the insulating resin layer of the printed circuit board must use resin with low relative dielectric constant and dielectric tangent. As resins with small relative permittivity and dielectric tangent, fluoropolymers such as polytetrafluoroethylene (PTFE) are known. As a material capable of forming a resin-attached metal foil having a resin layer containing a fluoropolymer, a powder dispersion in which a fluoropolymer powder is dispersed in a solvent is proposed (see Patent Documents 1 and 2). When the powder dispersion is mixed with other insulating resins and varnishes thereof, it has the advantage of being able to arbitrarily adjust various physical properties of the metal foil with resin. Furthermore, the powder dispersion also has the advantage of being able to form a resin-attached metal foil by simply coating and drying it on the surface of the metal foil.

Prior technical literature patent documents Patent Document 1: International Publication No. 2017/222027 Patent Document 2: International Publication No. 2016/159102

Summary of the invention The problem to be solved by the invention In terms of manufacturing methods of printed circuit boards, there are methods in which another substrate (prepreg, etc.) is laminated on the surface of a resin layer (insulating resin layer) containing a fluoropolymer to multi-layer metal foil with resin, or in which The surface of the aforementioned resin layer is laminated with other substrates (covering films, etc.) for encapsulation. At this time, from the viewpoint of the electrical characteristics and productivity of the printed circuit board, it is necessary to laminate the resin layer and other substrates in such a manner that the metal foil with resin is not warped. It is known that a resin-attached metal foil having a resin layer containing a fluoropolymer is subjected to surface treatment (plasma treatment, corona treatment, electron beam treatment, etc.) to control the warpage of the resin layer. However, this method requires In addition, metal foil with resin is used for surface treatment. Furthermore, surface treatment may cause temporal modification and shape change of the resin layer, thereby damaging the homogeneity of the resin layer.

The present inventors have made efforts to produce a resin-attached metal foil that has a highly homogeneous resin layer containing a fluoropolymer and is less likely to warp from a powder dispersion containing a fluoropolymer powder. As a result, they found that by adjusting the physical properties of the fluoropolymer and the manufacturing conditions of the resin-attached metal foil, the resin-attached metal foil can be efficiently produced. The present invention provides a resin-attached metal foil that has electrical properties and mechanical strength and is useful for manufacturing printed circuit boards, and an efficient manufacturing method thereof. The resin-attached metal foil has a highly homogeneous resin layer containing a fluoropolymer and is not easily warping.

means to solve problems The present invention has the following aspects. [1] A method of manufacturing a resin-attached metal foil, which is a method of manufacturing a resin-attached metal foil having a resin layer on the surface of the metal foil. The manufacturing method is as follows: A powder dispersion containing tetrafluoroethylene polymer powder and a solvent is coated on the surface of the metal foil. The temperature range of the tetrafluoroethylene polymer powder exhibiting a storage elastic modulus of 0.1 to 5.0 MPa is below 260°C. And the melting point exceeds 260℃, Keep the metal foil at a temperature within the aforementioned temperature zone, The tetrafluoroethylene polymer is further fired at a temperature exceeding the aforementioned temperature range to form a resin layer containing the tetrafluoroethylene polymer on the surface of the metal foil.

[2] The manufacturing method according to [1], wherein the warpage rate of the resin-coated metal foil is 7% or less. [3] The manufacturing method according to [1] or [2], wherein the thickness of the metal foil is 2 to 40 μm. [4] The manufacturing method according to any one of [1] to [3], wherein the thickness of the resin layer is 1 to 50 μm. [5] The manufacturing method according to any one of [1] to [4], wherein the thickness of the metal foil is 2 to 20 μm, and the thickness of the resin layer is 1 μm or more and less than 10 μm. [6] The manufacturing method according to any one of [1] to [5], wherein the volume-based cumulative 50% particle size of the powder is 0.05 to 6.0 μm. [7] The manufacturing method according to any one of [1] to [6], wherein the tetrafluoroethylene polymer is a polymer containing the following units: Units based on tetrafluoroethylene; and A unit mainly composed of at least one monomer selected from the group consisting of perfluoro(alkyl vinyl ether), hexafluoropropylene and fluoroalkylethylene.

[8] The production method according to any one of [1] to [7], wherein the tetrafluoroethylene polymer has: a group selected from the group consisting of a carbonyl group, a hydroxyl group, an epoxy group, a amide group, and an amine group. At least one functional group in the group consisting of a group and an isocyanate group. [9] The production method according to any one of [1] to [8], wherein the powder dispersion contains a polymeric polyol. [10] The manufacturing method according to any one of [1] to [9], wherein the metal foil is maintained in the aforementioned temperature range for 30 seconds to 5 minutes. [11] The manufacturing method according to any one of [1] to [10], wherein the gas environment when maintaining the metal foil in the aforementioned temperature range is a gas environment containing oxygen. [12] The manufacturing method according to any one of [1] to [11], wherein the temperature when firing the tetrafluoroethylene polymer exceeds 320°C.

[13] A metal foil with resin, which has a resin layer with a thickness of 1 μm or more and less than 10 μm on the surface of a metal foil with a thickness of 2 to 20 μm. The resin layer contains a polymer containing the following units: Units based on tetrafluoroethylene; and A unit mainly composed of at least one monomer selected from the group consisting of perfluoro(alkyl vinyl ether), hexafluoropropylene and fluoroalkylethylene; Furthermore, the warpage rate of the resin-coated metal foil is 7% or less. [14] The resin-coated metal foil described in [13] has a warpage rate of 5% or less. [15] A method of manufacturing a printed circuit board, which includes manufacturing a resin-coated metal foil using the manufacturing method described in any one of [1] to [12] above, and then etching the metal foil to form a pattern circuit.

Invention effect According to the present invention, a resin-attached metal foil having electrical properties and mechanical strength and useful for manufacturing printed circuit boards can be efficiently produced. The resin-attached metal foil has a highly homogeneous resin layer containing a fluoropolymer and is not prone to warping. song.

Form used to implement the invention The following terms have the following meanings. "Powder D50" uses the laser diffraction and scattering method to determine the volume-based cumulative 50% particle size of the powder. That is, the particle size distribution of the powder is measured using the laser diffraction scattering method, and the total volume of the particle group is 100%. After the accumulation curve is calculated, the particle size at the point where the cumulative volume is 50% on the accumulation curve. "Powder D90" uses the laser diffraction and scattering method to determine the volume-based cumulative 90% particle size of the powder. That is, the particle size distribution of the powder is measured using the laser diffraction scattering method, and the total volume of the particle group is 100%. After the accumulation curve is calculated, the particle size at the point where the cumulative volume is 90% on the accumulation curve. "Storage elastic modulus of polymer" is a value measured in accordance with ISO 6721-4: 1994 (JIS K7244-4: 1999). "Melting point of polymer" refers to the temperature corresponding to the maximum value of the melting peak measured by differential scanning calorimetry (DSC). "The warpage rate of resin-coated metal foil" is measured by cutting a 180mm square corner test piece from the resin-coated metal foil according to JIS C6471:1995 (corresponding to the international standard IEC 249-1:1982). The value obtained by measuring the method. "Dimensional change rate of metal foil with resin" is a value determined as follows. Cut the metal foil with resin into 150mm squares, use a 0.3mm drill bit to make holes at the four corners, and use a three-dimensional measuring device to measure the position of the holes. After removing the metal foil of the resin-attached metal foil by etching, it was dried at 130° C. for 30 minutes. Use a three-dimensional measuring device to measure the positions of the holes at the four corners. The dimensional change rate was calculated from the difference in hole positions before and after etching. "Arithmetic mean roughness Ra" is the arithmetic mean roughness measured in accordance with JIS B0601:2013 (ISO4287:1997, Amd.1:2009). When calculating Ra, the reference length lr (cutoff value λc) used for the thickness curve is set to 0.8 mm. "Heat-resistant resin" means a polymer compound with a melting point of 280°C or higher, or a polymer compound with a maximum continuous use temperature of 121°C or higher as specified in JIS C4003:2010 (IEC 60085:2007). "(Meth)acrylate" is the general term for acrylate and methacrylate.

The manufacturing method of the present invention is to apply a specific powder dispersion on the surface of a metal foil, heat and maintain the metal foil in stages under a specific temperature environment, and form a specific tetrafluoroethylene polymer (hereinafter) on the surface of the metal foil. Also referred to as "TFE-based polymer") resin layer method. In addition, the powder dispersion used is a dispersion in which TFE polymer powder is dispersed in a granular form.

Although the reason why the resin-attached metal foil produced according to the present invention has a resin layer (hereinafter also referred to as "F resin layer") containing a TFE-based polymer that is excellent in homogeneity and is not prone to warping is not yet clear, we believe that it is as follows. The TFE-based polymer of the present invention has predetermined meltability (having a melting point exceeding 260°C) and predetermined elasticity (having a storage elastic modulus of 0.1 to 5.0 MPa in a temperature range below 260°C), and under the aforementioned temperature range Form a certain elastic state. We believe that when a dispersion containing the TFE-based polymer powder is applied to the surface of a metal foil and maintained at a temperature within the aforementioned temperature range, the aforementioned powder will not be easily damaged due to the adhesiveness derived from elasticity, thereby forming a tightly packed structure. membrane state. We believe that in the present invention, the F resin layer is formed by firing the TFE-based polymer at a temperature exceeding the above-mentioned temperature range after forming the film state. Therefore, a highly homogeneous and dense F resin layer can be directly formed, thereby producing Resin-coated metal foil that is not easily warped.

The metal foil with resin of the present invention has an F resin layer on at least one surface of the metal foil. That is, the metal foil with resin may have the F resin layer only on one side of the metal foil, or may have the F resin layer on both sides of the metal foil. The warpage rate of the resin-coated metal foil is preferably 7% or less, preferably 5% or less. The lower limit of warpage is usually 0%. In this case, the handleability when processing the resin-attached metal foil to a printed circuit board and the resulting printed circuit board are excellent in transmission characteristics. The dimensional change rate of metal foil with resin should be ±1% or less, preferably ±0.2% or less. In this case, it is easy to multi-layer the printed circuit board made of the resin-coated metal foil.

The metal foil of the present invention may be made of copper, copper alloy, stainless steel, nickel, nickel alloy (including 42 alloy), aluminum, aluminum alloy, titanium, titanium alloy, etc. Examples of metal foil include rolled copper foil, electrolytic copper foil, and the like. An anti-rust layer (oxide film such as chromate, etc.), a heat-resistant layer, etc. may also be formed on the surface of the metal foil.

The ten-point average roughness of the metal foil surface should be 0.2~1.5μm. In this case, the adhesion with the F resin layer is good, and a printed circuit board with excellent transmission characteristics can be easily produced. The thickness of the metal foil is sufficient as long as it can function in the application of metal foil with resin, and it is preferably 2 μm or more, especially 3 μm or more. Moreover, the thickness of the metal foil is preferably 40 μm or less, preferably 20 μm or less, and especially 15 μm or less. The specific thickness of the metal foil can be 2~40μm, 2~20μm, 2~15μm, etc. The surface of the metal foil can be treated with the silane coupling agent. The entire surface of the metal foil can be treated with the silane coupling agent, or a part of the surface of the metal foil can be treated with the silane coupling agent.

The F resin layer of the present invention is a resin layer containing a TFE-based polymer formed from the powder dispersion of the present invention by the manufacturing method of the present invention.

F The water contact angle on the surface of the resin layer should be 70~100°, especially 70~90°. As long as the aforementioned range is below the upper limit, the adhesion between the F resin layer and other base materials will be better. As long as the aforementioned range is above the lower limit, the electrical characteristics (low dielectric loss and low dielectric constant) of the F resin layer will be better.

The thickness of the F resin layer is preferably 1 μm or more, preferably 2 μm or more, and especially 5 μm or more. Moreover, the thickness of the F resin layer is preferably 50 μm or less, preferably 15 μm or less, and particularly preferably less than 10 μm. Within this range, it is possible to easily balance the transmission characteristics of the printed circuit board and suppress the warpage of the resin-coated metal foil. When the metal foil with resin has F resin layers on both sides of the metal foil, from the viewpoint of suppressing warpage of the metal foil with resin, the composition and thickness of each F resin layer are preferably the same. Specific embodiments of the thickness of the F resin layer include 1 to 50 μm, such as 1 to 15 μm, 1 μm or more and less than 10 μm, 5 to 15 μm, and the like. Appropriate aspects of the thickness of the metal foil and the thickness of the F resin layer of the present invention include the former being 2 to 20 μm and the latter being 1 μm or more and less than 10 μm. In the manufacturing method of the present invention, a highly homogeneous and dense F-resin layer can be formed as described above. Therefore, even with such a thin resin-attached metal foil, warping can be suppressed.

The relative dielectric constant of the F resin layer should be 2.0~3.5, preferably 2.0~3.0. In this case, the F resin layer is excellent in both electrical properties and adhesion, and is suitable for use of resin-coated metal foil in printed circuit boards and the like that require low dielectric constants. Ra on the surface of the F resin layer is smaller than the thickness of the F resin layer and should be 2.2~8μm. Within this range, it is easy to balance the adhesion and processability with other substrates.

The powder containing the TFE-based polymer of the present invention (hereinafter also referred to as "F powder") may contain components other than the TFE-based polymer within the range that does not impair the effect of the present invention, but it is preferable to mainly use the TFE-based polymer. Element. The content of the TFE-based polymer in the F powder is preferably 80% by mass or more, and particularly preferably 100% by mass. The D50 of F powder should be 0.05~6.0μm, preferably 0.1~3.0μm, especially 0.2~3.0μm. Within this range, the fluidity and dispersibility of the F powder are good, and the electrical characteristics (low dielectric constant, etc.) and heat resistance of the TFE-based polymer in the resin-attached metal foil are most easily demonstrated. The D90 of F powder should be below 8 μm, preferably below 6 μm, and especially below 5 μm. The D90 of the powder should be above 0.3μm, especially above 0.8μm. Within this range, the fluidity and dispersibility of the F powder will be good, and the electrical characteristics (low dielectric constant, etc.) and heat resistance of the F resin layer will most easily appear. The bulk density of F powder should be above 0.05g/mL, especially 0.08~0.5g/mL. The densely packed density of F powder should be above 0.05g/mL, especially 0.1~0.8g/mL.

The manufacturing method of F powder is not particularly limited, and the method described in paragraphs [0065] to [0069] of International Publication No. 2016/017801 can be used. In addition, if there is a powder on the market that meets your expectations, F powder can also be used. The melting point of the TFE polymer of the present invention exceeds 260°C, and is preferably 260~320°C, especially 275~320°C, and most preferably 295~310°C. In this case, the TFE-based polymer can be fired while maintaining the adhesiveness derived from its elasticity, making it easier to form a fine F-resin layer.

The TFE-based polymer of the present invention exhibits a storage elastic modulus of 0.1 to 5.0 MPa in a temperature range below 260°C. For example, the storage elastic modulus of TFE polymer at 260°C is 0.1~5.0MPa. The storage elastic modulus exhibited by TFE-based polymers is preferably 0.2~4.4MPa, especially 0.5~3.0MPa. Furthermore, the temperature range for the TFE-based polymer to exhibit the storage elastic modulus is preferably in the range of 180 to 260°C, and particularly preferably in the range of 200 to 260°C. At this time, the F powder easily exhibits adhesiveness derived from elasticity in the aforementioned temperature range.

TFE-based polymers are polymers containing units (TFE units) mainly composed of tetrafluoroethylene (TFE). The TFE-based polymer may be a homopolymer of TFE or a copolymer of TFE and other monomers copolymerizable with TFE (hereinafter also referred to as comonomers). The TFE-based polymer preferably contains 75 to 100 mol% of TFE units relative to the total units contained in the polymer, and 0 to 25 mol% of units based on comonomers. Examples of TFE polymers include polytetrafluoroethylene (PTFE), copolymers of TFE and ethylene, copolymers of TFE and propylene, copolymers of TFE and perfluoro(alkyl vinyl ether) (PAVE) (PFA), Copolymer of TFE and hexafluoropropylene (HFP), copolymer of TFE and fluoroalkylethylene (FAE), copolymer of TFE and chlorotrifluoroethylene.

PAVE can enumerate CF ₂ =CFOCF ₃ , CF ₂ =CFOCF ₂ CF ₃ , CF ₂ =CFOCF ₂ CF ₂ CF ₃ (PPVE), CF ₂ =CFOCF ₂ CF ₂ CF ₂ CF ₃ , CF ₂ =CFO(CF ₂ ) _8F . Examples of FAE include CH ₂ =CH(CF ₂ ) ₂ F, CH ₂ =CH(CF ₂ ) ₃ F, CH ₂ =CH(CF ₂ ) ₄ F, CH ₂ =CF(CF ₂ ) ₃ H, CH ₂ = CF(CF ₂ ) _4H . An ideal aspect of the TFE-based polymer also includes a TFE unit and a unit mainly composed of at least one monomer selected from the group consisting of PAVE, HFP, and FAE (hereinafter also referred to as "comonomer unit"). F") polymer.

The aforementioned polymer preferably contains 90 to 99 mol% of TFE units and 1 to 10 mol% of comonomer units F relative to the total units contained in the polymer. The aforementioned polymer may only be composed of TFE units and comonomer units F, and may also include other units.

An ideal embodiment of the TFE-based polymer also includes at least one functional group selected from the group consisting of a carbonyl group-containing group, a hydroxyl group, an epoxy group, a amide group, an amine group, and an isocyanate group ( A polymer of TFE units (hereinafter also referred to as "functional group") (hereinafter also referred to as "polymer F1") The functional group may be contained in the unit in the TFE-based polymer, or may be contained in the terminal group of the main chain of polymer F1. Examples of the latter polymer include polymers having functional groups as terminal groups derived from a polymerization initiator, a chain transfer agent, and the like. Polymer F1 is preferably a polymer containing a unit having a functional group and a TFE unit. At this time, the polymer F1 preferably further contains other units, and particularly preferably contains the comonomer unit F. From the viewpoint of the adhesion between the F resin layer and the metal foil, the functional group is preferably a group containing a carbonyl group. Groups containing carbonyl groups include carbonate groups, carboxyl groups, haloformyl groups, alkoxycarbonyl groups, acid anhydride residues (-C(O)OC(O)-), fatty acid residues, etc., and carboxyl groups and acid anhydride residues The base is appropriate.

The unit having a functional group is preferably a unit mainly composed of a monomer having a functional group, preferably a unit mainly composed of a monomer having a carbonyl group-containing group, a unit mainly composed of a monomer having a hydroxyl group, or a unit mainly composed of a monomer having a hydroxyl group. The unit mainly composed of a monomer having an epoxy group and the unit mainly composed of a monomer having an isocyanate group is particularly preferably a unit mainly composed of a monomer having a carbonyl group-containing group. The monomer having a carbonyl group-containing group is preferably: a cyclic monomer having an acid anhydride residue, a monomer having a carboxyl group, vinyl ester or (meth)acrylate, and a cyclic monomer having an acid anhydride residue. Excellent. The aforementioned cyclic monomer is preferably: itaconic anhydride, citraconic anhydride, 5-norbornene-2,3-dicarboxylic anhydride (alias: nadic anhydride, also referred to as "NAH" below) or maleic anhydride. Polymer F1 is preferably a polymer containing units having functional groups, TFE units and PAVE units or HFP units. Specific examples of the polymer F1 include the polymer (X) described in International Publication No. 2018/16644.

The ratio of TFE units in polymer F1 is preferably 90 to 99 mole % of the total units contained in polymer F1. The ratio of PAVE units in polymer F1 is preferably 0.5 to 9.97 mol% based on the total units contained in polymer F1. The ratio of units having functional groups in polymer F1 is preferably 0.01 to 3 mol% of the total units contained in polymer F1.

The solvent of the present invention is a dispersion medium. It is a liquid, inactive solvent compound that does not react with F powder at 25°C. It is preferable that the boiling point is lower than the components other than the solvent contained in the powder dispersion and it can be heated, etc. Solvent compounds removed by evaporation. Examples of solvent compounds include: water, alcohol (methanol, ethanol, isopropyl alcohol, etc.), nitrogen-containing compounds (N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl- 2-pyrrolidinone, etc.), sulfur-containing compounds (dimethyltrisoxide, etc.), ethers (diethyl ether, dimethyl ether, etc.) Alkanes, etc.), esters (ethyl lactate, ethyl acetate, etc.), ketones (methyl ethyl ketone, methyl isopropyl ketone, cyclopentanone, cyclohexanone, etc.), glycol ethers (ethylene glycol monoisopropyl ketone, etc.) Propyl ether, etc.), cellulose (cellulose A, cellulose B, etc.), etc. The solvent compound may be used individually by 1 type or in combination of 2 or more types. The solvent compound is preferably a solvent that does not volatilize instantly, and a solvent compound with a boiling point of 80 to 275°C is preferred, and a solvent compound with a boiling point of 125 to 250°C is particularly preferred. Within this range, the stability of the wet film (solvent-containing film) formed from the powder dispersion applied to the surface of the metal foil is high. The solvent in the wet film will be removed before the firing of the TFE-based polymer is completed. The vaporization and dissipation of the solvent from the wet film may occur before reaching the temperature range exhibiting the specific storage elastic modulus, or may occur while maintaining the temperature range exhibiting the specific storage elastic modulus. Depending on the situation, it may be generated when the TFE-based polymer is fired. Ideally, a solvent in the above boiling point range is used, and at least part of the solvent in the wet film is vaporized and dissipated while the TFE polymer is maintained in a temperature range exhibiting the specific storage elastic modulus. The solvent compound is preferably an organic compound, preferably cyclohexane (boiling point: 81°C), 2-propanol (boiling point: 82°C), 1-propanol (boiling point: 97°C), and 1-butanol (boiling point: 117 ℃), 1-methoxy-2-propanol (boiling point: 119℃), N-methylpyrrolidone (boiling point: 202℃), γ-butyrolactone (boiling point: 204℃), cyclohexanone ( Boiling point: 156°C) and cyclopentanone (boiling point: 131°C), especially N-methylpyrrolidone, γ-butyrolactone, cyclohexanone and cyclopentanone.

The ratio of F powder in the powder dispersion is preferably 5 to 60 mass %, and 35 to 50 mass % is particularly preferred. Within this range, it is easy to control the relative dielectric constant and dielectric tangent of the F resin layer. Furthermore, the powder dispersion has high uniform dispersion and the F resin layer has excellent mechanical strength. The ratio of the solvent in the powder dispersion is preferably 15 to 65 parts by mass, especially 25 to 50 parts by mass. Within this range, the coating properties of the powder dispersion are good, and the resin layer is less likely to have poor appearance.

The powder dispersion of the present invention may contain other materials within the scope that does not impair the effects of the present invention. Other materials may or may not be soluble in the powder dispersion. From the viewpoint of improving the dispersion stability of the powder dispersion, the powder dispersant preferably contains a dispersant. From the viewpoint of imparting adhesiveness to the surface properties of the F resin layer, the dispersant is particularly preferably a compound (surfactant) having a hydrophobic portion and a hydrophilic portion. When the powder dispersion contains a dispersant, the proportion of the dispersant in the powder dispersion is preferably 0.1 to 30 parts by mass, especially 5 to 10 parts by mass. Within this range, it is easy to balance the uniform dispersion of the F powder with the hydrophilicity and electrical characteristics of the surface of the F resin layer.

The dispersant of the present invention is preferably polyol, polyoxyalkylene glycol, polycaprolactam and polymeric polyol, and polymeric polyol is preferred. Polymeric polyol means a polymer having units mainly composed of monomers having carbon-carbon unsaturated double bonds and two or more hydroxyl groups. Polymeric polyols are particularly preferably polyvinyl alcohol, polyvinyl butyral and fluoropolyols, with fluoropolyols being the most preferred. However, fluoropolyol is not a TFE-based polymer, but a polymer containing hydroxyl groups and fluorine atoms. In addition, fluoropolyols may also be chemically modified or modified by chemically modifying part of the hydroxyl groups.

The fluoropolyol is composed of a (meth)acrylate having a polyfluoroalkyl group or a polyfluoroalkenyl group (hereinafter also referred to as "(meth)acrylate F") and a (methyl)ol group having a polyoxyalkylene unit alcohol group. A copolymer (hereinafter also referred to as "dispersed polymer F") of ) acrylate (hereinafter also referred to as "(meth)acrylate AO") is particularly preferred. The (meth)acrylate ^F is preferably a compound represented by the formula CH ₂ =CR ¹ C(O)OX ¹ -RF. R ¹ represents a hydrogen atom or a methyl group. X ¹ represents -(CH ₂ ) ₂ -, -(CH ₂ ) ₃ -, -(CH ₂ ) ₄ -, -(CH ₂ ) ₂ NHC(O)-, -(CH ₂ ) ₃ NHC(O)- or -CH ₂ CH(CH ₃ )NHC(O)-. R ^F represents -OCF(CF ₃ )(C(CF(CF ₃ ) ₂ )(=C(CF ₃ ) ₂ ), -OC(CF ₃ )(=C(CF(CF ₃ ) ₂ )(CF(CF ₃ ) ₂ ), -OCH(CH ₂ OCH ₂ CH ₂ (CF ₂ ) ₄ F) _{2 ,} -OCH(CH ₂ OCH ₂ CH ₂ (CF ₂ ) ₆ F) ₂ , -(CF ₂ ) ₄ F or - (CF ₂ ) ₆ F. (Meth)acrylate AO is preferably a compound represented by the formula CH ₂ =CR ² C(O)OQ ² -OH. R ² represents a hydrogen atom or a methyl group. Q ² represents -(CH ₂ ) _m (OCH ₂ CH ₂ ) _n -, -(CH ₂ ) _m (OCH ₂ CH(CH ₃ )) _n -or-(CH ₂ ) _m (OCH ₂ CH ₂ CH ₂ CH ₂ ) _n -(m represents an integer from 1 to 4, n represents an integer from 2 to 100, and n is preferably an integer from 2 to 20).

Specific examples of (meth)acrylate F include CH ₂ =CHCOO(CH ₂ ) ₄ OCF(CF ₃ )(C(CF(CF ₃ ) ₂ )(=C(CF ₃ ) ₂ ), CH ₂ =CHCOO (CH ₂ ) ₄ OC(CF ₃ )(=C(CF(CF ₃ ) ₂ )(CF(CF ₃ ) ₂ ), CH ₂ =C(CH ₃ )COO(CH ₂ ) ₂ NHCOOCH(CH ₂ OCH ₂ CH ₂ (CF ₂ ) ₆ F) ₂ , CH ₂ ＝C(CH ₃ )COO(CH ₂ ) ₂ NHCOOCH(CH ₂ OCH ₂ CH ₂ (CF ₂ ) ₄ F) ₂ , CH ₂ ＝C(CH ₃ ) COO(CH ₂ ) ₂ NHCOOCH(CH ₂ OCH ₂ (CF ₂ ) ₆ F) ₂ , CH ₂ ＝C(CH ₃ )COO(CH ₂ ) ₂ NHCOOCH(CH ₂ OCH ₂ (CF ₂ ) ₄ F) ₂ , CH ₂ ＝C(CH ₃ )COO(CH ₂ ) ₃ NHCOOCH(CH ₂ OCH ₂ (CF ₂ ) ₆ F) ₂ , CH ₂ ＝C(CH ₃ )COO(CH ₂ ) ₃ NHCOOCH(CH ₂ OCH ₂ ( CF ₂ ) ₄ F) _2. Specific examples of (meth)acrylate AO include CH ₂ =CHCOO(CH ₂ CH ₂ O) ₈ OH, CH ₂ =CHCOO(CH ₂ CH ₂ O) ₁₀ OH, CH ₂ ＝CHCOO(CH ₂ CH ₂ O) ₁₂ OH, CH ₂ ＝C(CH ₃ )COO(CH ₂ CH(CH ₃ )O) ₈ OH, CH ₂ ＝C(CH ₃ )COO(CH ₂ CH(CH ₃ )O) ₁₂ OH, CH ₂ =C(CH ₃ )COO(CH ₂ CH(CH ₃ )O) ₁₆ OH.

Relative to the total units contained in the dispersion polymer F, the ratio of units mainly composed of (meth)acrylate F is preferably 20 to 60 mol%, and particularly preferably 20 to 40 mol%. Relative to the total units contained in the dispersion polymer F, the ratio of units mainly composed of (meth)acrylate AO is preferably 40 to 80 mol%, and particularly preferably 60 to 80 mol%. The dispersion polymer F may be composed only of units mainly composed of (meth)acrylate AO and units mainly composed of (meth)acrylate AO, and may further contain other units. The fluorine content of the dispersion polymer F is preferably 10 to 45% by mass, and particularly preferably 15 to 40% by mass. The dispersion polymer F is preferably nonionic. The mass average molecular weight of the dispersed polymer F is preferably 2,000 to 80,000, especially 6,000 to 20,000.

The powder dispersion of the present invention may further contain other materials besides the dispersant. The other materials may be non-hardening resin or hardening resin. Examples of the non-hardening resin include heat-melting resin and non-melting resin. Examples of the heat-melting resin include thermoplastic polyimide and the like. Examples of the non-melting resin include cured products of curable resins. Examples of the curable resin include polymers having reactive groups, oligomers having reactive groups, low molecular compounds, low molecular compounds having reactive groups, etc. Examples of reactive groups include carbonyl-containing groups, hydroxyl groups, amine groups, epoxy groups, and the like.

Examples of curable resins include: epoxy resin, thermosetting polyimide, polyamide precursor of polyimide, thermosetting acrylic resin, phenol resin, thermosetting polyester resin, thermosetting polyamide Olefin resin, thermosetting modified polyphenylene ether resin, multifunctional cyanate ester resin, multifunctional maleimide-cyanate ester resin, multifunctional maleimide resin, vinyl ester resin, urea resin , diallyl phthalate resin, melamine resin, guanamine resin, melamine-urea co-condensation resin. Among them, thermosetting resins include thermosetting polyimide, polyimide precursor, epoxy resin, thermosetting acrylic resin, and bismaleimide resin from the viewpoint of their use in printed circuit boards. and thermosetting polyphenylene ether resin are preferred, and epoxy resin and thermosetting polyphenylene ether resin are particularly preferred.

Specific examples of epoxy resins include: naphthalene type epoxy resin, cresol novolac type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, alicyclic type Epoxy resin, aliphatic chain epoxy resin, cresol novolak type epoxy resin, phenol novolac type epoxy resin, alkylphenol novolac type epoxy resin, aralkyl type epoxy resin, biphenol type epoxy resin , dicyclopentadiene type epoxy resin, hydroxyphenylmethane type epoxy compound, epoxide of the condensate of phenol and aromatic aldehyde with phenolic hydroxyl group, bisphenol diepoxypropyl etherate, Diglycidyl etherate of naphthalenediol, glycidyl etherate of phenol, diglycidyl etherate of alcohol, tripoxypropyl isocyanate, etc. Examples of the bismaleimide resin include a resin composition (BT resin) in which a bisphenol A-type cyanate ester resin and a bismaleimide compound are used together as described in Japanese Patent Application Laid-Open No. 7-70315, or a resin composition such as The invention described in International Publication No. 2013/008667 and the matter described in the background of the invention. Polyamides generally have reactive groups that can react with the functional groups of polymer F1. Examples of diamines and polycarboxylic dianhydrides that form polyamic acid include: paragraph [0020] of Japanese Patent No. 5766125, paragraph [0019] of Japanese Patent No. 5766125, and Japanese Patent Application Laid-Open No. 2012-145676 Things described in paragraphs [0055], [0057], etc. of the Gazette. Among them, aromatic diamines such as 4,4'-diaminodiphenyl ether, 2,2-bis[4-(4-aminophenoxy)phenyl]propane and 1,2,4 , 5-pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenylkettracarboxylic dianhydride and other aromatic polycarboxylic acids Polyamic acid composed of a combination of dianhydrides is preferred.

Examples of the heat-melting resin include thermoplastic resins such as thermoplastic polyimide and heat-melting cured products of curable resins. Examples of thermoplastic resins include: polyester resin, polyolefin resin, styrene resin, polycarbonate, thermoplastic polyimide, polyarylate, polyurethane, polyarylethylene, aromatic polyamide, aromatic polyetheramide Amine, polyphenylene sulfide, polyaryl ether ketone, polyamide imine, liquid crystalline polyester, polyphenylene ether, etc., with thermoplastic polyimide, liquid crystalline polyester and polyphenylene ether being suitable.

In addition, other materials that can be included in the powder dispersion of the present invention include: binders, thixotropy imparting agents, defoaming agents, inorganic fillers, reactive alkoxysilane, dehydrating agents, plasticizers, weathering agents, anti-foaming agents, etc. Oxidants, heat stabilizers, lubricants, antistatic agents, whitening agents, colorants, conductive agents, release agents, surface treatment agents, viscosity regulators, flame retardants, etc. If the powder dispersion of the present invention contains a binder, it can prevent the F powder from falling off the metal foil when forming the F resin layer. The binder may be a thermoplastic organic binder or a thermosetting organic binder. The binder is preferably a compound that decomposes and volatilizes within the temperature range in which the TFE-based polymer is fired. Examples of such adhesives include acrylic resin adhesives, cellulose resin adhesives, vinyl alcohol resin adhesives, wax resin adhesives, gelatin, and the like. One type of binder may be used alone or two or more types may be used in combination.

In the present invention, the powder dispersion is applied to the surface of the metal foil. The coating method is any method as long as it can form a stable wet film composed of a powder dispersion on the surface of the coated metal foil. Examples include: spray coating, roller coating, spin coating, gravure coating, and micro coating. Gravure coating method, gravure flat plate method, blade coating method, contact coating method, rod coating method, die coating method, fountain meyer bar method, slit die coating method, etc. In addition, before supplying the metal foil to a temperature range where the TFE-based polymer exhibits a storage elastic modulus of 0.1 to 5.0 MPa, the metal foil can also be heated at a temperature lower than the aforementioned temperature range to adjust the state of the wet film. In addition, the adjustment is performed to the extent that the solvent is not completely volatilized, and is usually performed to the extent that 50% by mass or less of the solvent is volatilized.

In the present invention, after the powder dispersion is applied to the surface of the metal foil, it is maintained at a temperature in a temperature range in which the TFE-based polymer exhibits a storage elastic modulus of 0.1 to 5.0 MPa (hereinafter also referred to as "maintenance temperature") Metal foil. The holding temperature represents the temperature of the gas environment. Maintenance can be implemented in one stage, or more than two stages at different temperatures. Examples of maintenance methods include: using an oven, using a ventilated drying oven, irradiating heat rays such as infrared rays, etc. The gas environment to be maintained can be either under normal pressure or under reduced pressure. In addition, the gas environment to be maintained may be any one of an oxidizing gas (oxygen, etc.) environment, a reducing gas (hydrogen, etc.) environment, and an inactive gas (helium, neon, argon, nitrogen, etc.) environment. From the perspective of improving the adhesion of the F resin layer, the gas environment maintained is preferably an oxygen-containing gas environment. The oxygen concentration (volume basis) in an oxygen-containing gas environment is preferably 1×10 ² ~3×10 ⁵ ppm, especially 0.5×10 ³ ~1×10 ⁴ ppm. Within this range, it is easy to balance the adhesion of the F resin layer and suppress the oxidation of the metal foil. The maintenance temperature should be 150~260℃, especially 200~260℃. The time to maintain the temperature should be 0.1 to 10 minutes, especially 0.5 to 5 minutes.

In the present invention, the TFE-based polymer is further fired at a temperature exceeding the aforementioned temperature range (hereinafter also referred to as "firing temperature") to form an F-resin layer on the surface of the metal foil. The firing temperature represents the temperature of the gas environment. In the present invention, the TFE-based polymer is welded in a state where the F powder is densely packed. Therefore, an F resin layer with excellent homogeneity can be formed, and the metal foil with the resin is less likely to warp. In addition, as long as the powder dispersion contains a thermofusible resin, it can form an F-resin layer composed of a mixture of TFE-based polymer and soluble resin. As long as the powder dispersion contains a thermosetting resin, it can form an F-resin layer composed of a TFE-based polymer. F resin layer composed of hardened material of thermosetting resin. Heating methods include: using an oven, using a ventilated drying furnace, irradiating heat rays such as infrared rays, etc. In order to improve the smoothness of the surface of the F resin layer, pressure can also be applied with a heating plate, heating roller, etc. From the viewpoint that it can be fired in a short time and the far-infrared furnace is relatively simple, the heating method is preferably a method of irradiating far-infrared rays. The heating method can also combine infrared heating and hot air heating. From the perspective of promoting homogeneous welding of TFE-based polymers, the effective wavelength band of far-infrared rays is preferably 2 to 20 μm, and 3 to 7 μm is preferred.

The gas environment for firing can be either under normal pressure or under reduced pressure. In addition, the gas environment for the aforementioned firing may be an oxidizing gas (oxygen, etc.) gas environment, a reducing gas (hydrogen, etc.) gas environment, or an inactive gas (helium, neon, argon, nitrogen, etc.) gas environment. Either way, from the viewpoint of suppressing oxidative deterioration of the metal foil and the formed F resin layer, a reducing gas environment or an inert gas environment is preferable. The gas environment for firing is preferably a gas environment composed of inert gas and with a low oxygen concentration, and preferably a gas environment composed of nitrogen with an oxygen concentration (volume basis) of less than 500 ppm. The oxygen concentration (volume basis) is preferably 300 ppm or less. In addition, the oxygen concentration (volume basis) is usually 1 ppm or more.

The firing temperature should exceed 320℃, especially 330~380℃. In this case, the TFE-based polymer forms a dense F-resin layer more easily. The time to maintain the firing temperature should be 30 seconds to 5 minutes, especially 1 to 2 minutes. When the resin layer in the metal foil with resin is a conventional insulating material (hardened product of thermosetting resin such as polyimide), it must be heated for a long time to harden the thermosetting resin. On the other hand, in the present invention, the resin layer can be formed by welding the TFE-based polymer and heating for a short time. In addition, when the powder dispersion contains a thermosetting resin, the firing temperature can be lowered. In this way, the manufacturing method of the present invention is a method that imposes a small thermal load on the metal foil when the resin layer is formed on the metal foil with resin, that is, a method that causes less damage to the metal foil.

In the metal foil with resin of the present invention, in order to control the linear expansion coefficient of the F resin layer or further improve the adhesion of the F resin layer, the surface of the F resin layer may also be surface treated. Surface treatment methods for the surface of the F resin layer include: annealing treatment, corona discharge treatment, atmospheric pressure plasma treatment, vacuum plasma treatment, UV ozone treatment, excimer treatment, chemical etching, silane coupling treatment, micro-roughening processing etc. The temperature of annealing treatment should be 80~190℃, especially 120~180℃. The pressure of annealing treatment should be 0.001~0.030MPa, especially 0.005~0.015MPa. The annealing treatment time should be 10 to 300 minutes, especially 30 to 120 minutes. Plasma irradiation devices for plasma treatment include: high-frequency induction method, capacitive coupling electrode method, corona discharge electrode-plasma jet method, parallel plate type, remote plasma type, atmospheric pressure plasma type, and ICP type high density Plasma type etc. Gases used in plasma treatment include oxygen, nitrogen, rare gases (argon, etc.), hydrogen, ammonia, etc., and are preferably rare gases or nitrogen. Specific examples of gases used in plasma processing include argon gas; a mixed gas of hydrogen and nitrogen; and a mixed gas of hydrogen, nitrogen and argon. The gas environment for plasma treatment should be a gas environment with a volume fraction of rare gas or nitrogen of more than 70% by volume, and a gas environment of 100% by volume is particularly preferred. Within this range, adjusting the Ra of the surface of the F resin layer to 2.0 μm or less makes it easier to form fine unevenness on the surface of the F resin layer.

The F-resin layer of the resin-attached metal foil produced by the present invention has excellent surface homogeneity and is not prone to warping, so it can be easily laminated with other substrates. Examples of other substrates include a heat-resistant resin film, a prepreg that is a precursor of a fiber-reinforced resin board, a laminate having a heat-resistant resin film layer, a laminate having a prepreg layer, and the like. The prepreg system is a sheet-like substrate in which a base material (fiber bundle, woven fabric, etc.) of reinforced fiber (glass fiber, carbon fiber, etc.) is impregnated with thermosetting resin or thermoplastic resin. The heat-resistant resin film is a film containing one or more types of heat-resistant resin, and may be a single-layer film or a multi-layer film. Examples of heat-resistant resins include polyimide, polyarylate, polystyrene, polyaryl sulfide, aromatic polyamide, aromatic polyether amide, polyphenylene sulfide, polyaryl ether ketone, and polyamide amide. imine, liquid crystalline polyester, etc.

A method of laminating other base materials on the surface of the F resin layer of the resin-attached metal foil of the present invention may include a method of hot pressing the resin-attached metal foil and other substrates. When other substrates are prepregs, the pressing temperature should be below the melting point of the TFE polymer, preferably 120 to 300°C, and especially 160 to 220°C. Within this range, thermal deterioration of the prepreg can be suppressed, and the F resin layer and the prepreg can be firmly bonded. When the substrate is a heat-resistant resin film, the pressing temperature is preferably 310 to 400°C. Within this range, thermal deterioration of the heat-resistant resin film can be suppressed, and the F resin layer and the heat-resistant resin film can be firmly bonded.

Hot pressing should be carried out in a reduced pressure environment, especially under a vacuum degree below 20kPa. Within this range, air bubbles can be suppressed from being mixed into each interface of the F resin layer, the substrate, and the metal foil of the laminate, thereby suppressing deterioration due to oxidation. Furthermore, during hot pressing, it is preferable to raise the temperature after reaching the aforementioned vacuum degree. If the temperature is raised before reaching the aforementioned vacuum degree, the F resin layer will be pressed and bonded in a softened state, that is, in a state with a certain degree of fluidity and adhesion, and bubbles will be formed. The pressure of hot pressing should be above 0.2MPa. The upper limit of pressure should be below 10MPa. Within this range, damage to the substrate can be suppressed and firm contact between the F resin layer and the substrate can be achieved.

The resin-attached metal foil and its laminate of the present invention can be used as a flexible copper-clad laminated board or a rigid copper-clad laminated board for manufacturing printed circuit boards. For example, a printed circuit board can be produced from the metal foil with resin of the present invention using the following method: a method of processing the metal foil of the metal foil with resin of the present invention into a conductor circuit (pattern circuit) of a predetermined pattern by etching or the like; or It is a method of processing the resin-attached metal foil of the present invention into a patterned circuit using an electroplating method (semi-additive method (SAP method), modified semi-additive method (MSAP method), etc.). When manufacturing a printed circuit board, an interlayer insulating film may be formed on the pattern circuit after the pattern circuit is formed, and the pattern circuit may be further formed on the interlayer insulating film. The interlayer insulating film can be formed, for example, from the powder dispersion of the present invention. When manufacturing a printed circuit board, a solder mask layer can also be laminated on the pattern circuit. The solder mask layer can be formed, for example, by the powder dispersion of the present invention. When manufacturing a printed circuit board, a cover film can also be laminated on the pattern circuit. The covering film can be formed, for example, from the powder dispersion of the present invention. Example

Hereinafter, the present invention will be described in detail using examples, but the present invention is not limited thereto. Various assay methods are shown below.

＜Melting point of polymer＞ Using a differential scanning calorimeter (DSC-7020, manufactured by Seiko Instruments Inc.), the temperature of the TFE-based polymer was increased at a rate of 10° C./min and measured. ＜Storage elastic modulus of polymer＞ According to ISO 6721-4: 1994 (JIS K7244-4: 1999), a dynamic viscoelasticity measuring device (DMS6100, manufactured by SII NanoTechnology Inc.) was used under the conditions of frequency 10Hz, static force 0.98N, and dynamic displacement 0.035%. The temperature was raised from 20°C at a speed of 2°C/min, and the storage elastic modulus at 260°C was measured. ＜Powder D50 and D90＞ Using a laser diffraction/scattering particle size distribution measuring device (LA-920 measuring device manufactured by Horiba Manufacturing Co., Ltd.), the powder was dispersed in water and then measured.

＜Homogeneity of resin layer＞ Visually observe the resin layer after light irradiation from diagonally above, and make an evaluation based on the following criteria. ○: The pattern has not been confirmed. △: Orange peel pattern is confirmed. ×: An orange peel pattern was observed, and resin peeling was observed in the center at the ends. ＜Warp rate of metal foil with resin＞ Cut out a 180 mm square test piece with four corners from the resin-coated metal foil, and measure the test piece according to the measurement method specified in JIS C6471:1995. ○: The warpage rate of resin-coated metal foil is 5% or less. △: The warpage rate of the metal foil with resin exceeds 5% and is less than 7%. ×: The warpage rate of the resin-coated metal foil exceeds 7%.

[TFE polymer] Polymer 1: A copolymer containing units based on TFE, units based on NAH, and units based on PPVE in order of 97.9 mol%, 0.1 mol%, and 2.0 mol%. The melting point is 300°C. , and a polymer with a storage elastic modulus of 1.1MPa at 260°C. Polymer 2: A copolymer containing TFE as the main unit and PPVE as the main unit in order of 98 mol% and 2 mol%, the melting point is 310°C, and the storage elastic modulus at 260°C is 4.8 MPa polymer. Polymer 3: A copolymer containing TFE as the main unit and HFP as the main unit in order of 82 mol% and 18 mol%, the melting point is 265°C, and the storage elastic modulus at 260°C is 0.5 MPa polymer. Polymer 4: A polymer containing more than 99.5 mol% of TFE-based units, a polymer with a melting point exceeding 320°C, and a storage elastic modulus at 260°C greater than 5.0MPa.

[Dispersant] Dispersant 1: Copolymer (nonionic surfactant) of an acrylate having a perfluoroalkenyl group and an acrylate having a polyoxyethylene group and an alcoholic hydroxyl group. [metal foil] Copper foil 1: Low-roughened copper foil with a thickness of 12 μm (average roughness at ten points on the surface: 0.6 μm).

[powder] Powder 1: Powder of polymer 1 with D50 of 1.7 μm and D90 of 3.8 μm (loose bulk density: 0.269 g/mL, tightly packed bulk density: 0.315 g/mL). Powder 2: Powder of polymer 2 with D50 of 2.4 μm and D90 of 5.5 μm. Powder 3: Powder of polymer 3 with D50 of 3.1 μm and D90 of 5.9 μm. Powder 4: Powder of polymer 4 with D50 of 0.3 μm and D90 of 0.6 μm.

[example 1] Dispersion 1 was prepared by mixing 50 parts by mass of powder 1, 5 parts by mass of dispersant 1, and 45 parts by mass of N-methylpyrrolidone. After applying the dispersion 1 on the surface of the copper foil 1 using a die coater, the copper foil 1 is passed through a ventilated drying furnace (gas ambient temperature: 260°C, ambient gas: nitrogen with an oxygen concentration of 8000 ppm) and held for 1 minute, and then Pass the far-infrared furnace (temperature: 340°C, gas: nitrogen with an oxygen concentration lower than 100 ppm) for 1 minute to prepare resin-attached copper with a resin layer (thickness 5 μm) of polymer 1 on the surface of copper foil 1 foil. The evaluation results regarding the homogeneity of the resin layer and the warpage rate of the metal foil with resin are listed in Table 1 below.

[Examples 2 to 5] Except for changing the powder and the gas ambient temperature of the ventilation drying furnace, resin-coated copper foils were produced in the same manner as Example 1, and evaluated separately. The results are summarized in Table 1 below. [Table 1]

industrial availability The manufacturing method of the present invention is a method suitable for manufacturing a resin-attached metal foil that has a highly homogeneous resin layer containing a fluoropolymer and is difficult to warp and is useful for manufacturing printed circuit boards and the like. In addition, the entire contents of the specification, patent scope and abstract of Japanese Patent Application No. 2018-104010 filed on May 30, 2018 are quoted here and incorporated into the disclosure of the specification of the present invention.

Claims (13)

A method of manufacturing a resin-attached metal foil, which is a method of manufacturing a resin-attached metal foil having a resin layer on the surface of the metal foil. The manufacturing method is as follows: applying a powder dispersion containing tetrafluoroethylene polymer powder and a solvent to On the surface of the metal foil, the temperature range in which the tetrafluoroethylene polymer powder exhibits a storage elastic modulus of 0.1 to 5.0 MPa is below 260°C and the melting point exceeds 260°C. The metal foil is maintained at a temperature within the aforementioned temperature range. The tetrafluoroethylene polymer is further fired at a temperature exceeding the aforementioned temperature range to form a resin layer containing the tetrafluoroethylene polymer on the surface of the metal foil. The manufacturing method of claim 1, wherein the warpage rate of the resin-coated metal foil is 7% or less. Such as the manufacturing method of claim 1 or 2, wherein the thickness of the metal foil is 2~40 μm. Such as the manufacturing method of claim 1 or 2, wherein the thickness of the resin layer is 1~50 μm. Such as the manufacturing method of claim 1 or 2, wherein the thickness of the metal foil is 2~20 μm, and the thickness of the resin layer is more than 1 μm and less than 10 μm. Such as the manufacturing method of claim 1 or 2, wherein the cumulative 50% particle size of the powder on a volume basis is 0.05~6.0 μm. The manufacturing method of claim 1 or 2, wherein the tetrafluoroethylene polymer is a polymer containing the following units: A unit mainly composed of tetrafluoroethylene; and a unit mainly composed of at least one monomer selected from the group consisting of perfluoro(alkyl vinyl ether), hexafluoropropylene and fluoroalkylethylene. The manufacturing method of claim 1 or 2, wherein the tetrafluoroethylene polymer has: a group selected from the group consisting of a carbonyl group, a hydroxyl group, an epoxy group, a amide group, an amine group and an isocyanate group. At least 1 functional group. The manufacturing method of claim 1 or 2, wherein the powder dispersion contains polymeric polyol. For example, according to the manufacturing method of claim 1 or 2, the time for keeping the metal foil in the aforementioned temperature range is 30 seconds to 5 minutes. According to the manufacturing method of Claim 1 or 2, the gas environment when the metal foil is maintained in the aforementioned temperature range is a gas environment containing oxygen. For example, in the manufacturing method of claim 1 or 2, the temperature when firing the tetrafluoroethylene polymer exceeds 320°C. A method of manufacturing a printed circuit board, which includes manufacturing a resin-coated metal foil using the manufacturing method according to any one of claims 1 to 12, and then etching the metal foil to form a pattern circuit.