CN109661862B - Metal laminate, method for producing same, and method for producing printed board - Google Patents

Abstract

The purpose of the present invention is to provide a metal laminate plate, a method for manufacturing the same, and a method for manufacturing a printed circuit board, wherein excellent electrical characteristics are ensured, and sufficient adhesion strength can be obtained between an insulating layer and an adhesive layer, and between an adhesive layer and a conductive layer. The metal laminated plate 1 comprises an insulating layer 10, an adhesive layer 12 and a conductive layer 14, wherein the insulating layer 12 contains a fluororesin-containing resin powder 16, the resin powder 16 contains particles (A)16a having a particle diameter of 10 [ mu ] m or more and does not contain particles having a particle diameter exceeding the total thickness of the insulating layer 10 and the adhesive layer 12, and the surface 10a of the insulating layer 10 on which the adhesive layer 12 is provided has a surface roughness of 0.5 to 3.0 [ mu ] m. Further, a method for manufacturing the metal laminated plate 1 and a method for manufacturing a printed board using the metal laminated plate 1 are also provided.

Description

Metal laminate, method for producing same, and method for producing printed board

Technical Field

The present invention relates to a metal laminate, a method for manufacturing the same, and a method for manufacturing a printed circuit board.

Background

In recent years, with the weight reduction, size reduction, and density increase of electronic products, the demand for various printed boards has been increasing. The printed board is a metal laminate in which a conductive layer made of a metal foil is laminated on an insulating layer made of an insulating material such as polyimide through an adhesive layer. The conductive layer of the metal laminate is patterned to form a circuit, thereby producing a printed circuit board. Recently, printed boards are required to have excellent electrical characteristics (low dielectric constant, etc.) corresponding to frequencies in a high frequency band.

As an insulating layer having a low dielectric constant and useful for a printed circuit board, a substrate containing a polyimide and a fluoropolymer fine powder (resin powder) made of Polytetrafluoroethylene (PTFE) and having an average particle diameter of 0.02 to 5 μm has been proposed (patent document 1). Further, a substrate comprising a thermosetting resin such as polyimide and a resin powder having an average particle diameter of 0.02 to 50 μm and a fluorine-containing copolymer having a functional group such as a carbonyl group is proposed (patent document 2).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2005-142572

Patent document 2: international publication No. 2016/017801

Disclosure of Invention

Technical problem to be solved by the invention

However, the present inventors have studied and found that, in a printed circuit board having a laminated structure of an insulating layer/an adhesive layer/a conductive layer, or a conductive layer/an adhesive layer/an insulating layer/an adhesive layer/a conductive layer, when the substrate of patent documents 1 and 2 is used as an insulating layer, sufficient adhesion strength between the insulating layer and the adhesive layer, or between the adhesive layer and the conductive layer cannot be obtained. If the content of the resin powder is reduced, the interlayer adhesion strength can be improved, but it is difficult to secure excellent electrical characteristics.

The purpose of the present invention is to provide a metal laminate plate, a method for producing the same, and a method for producing a printed circuit board using the metal laminate plate, wherein excellent electrical characteristics are ensured, and sufficient adhesion strength can be obtained between the insulating layer and the adhesive layer, and between the adhesive layer and the conductive layer.

Technical scheme for solving technical problem

The present inventors have conducted extensive studies and found that the adhesion strength between the insulating layer and the adhesive layer can be improved by the anchor effect by making the surface of the insulating layer on the adhesive layer side moderately rough by making the resin powder contained in the insulating layer include particles having a particle diameter of 10 μm or more. Further, by controlling the particle diameter of the particles contained in the resin powder so that the particles do not reach the interlayer between the adhesive layer and the conductive layer, it is possible to suppress the occurrence of the adhesion between the adhesive layer and the conductive layer being inhibited by the resin powder, and to ensure sufficient adhesion strength between the adhesive layer and the conductive layer. Based on these findings, the present invention has been completed.

The present invention has the following configuration.

[1] A kind of metal laminated plate is disclosed,

which comprises an insulating layer, an adhesive layer provided on at least one surface of the insulating layer in a thickness direction thereof, and a conductive layer provided on a surface of the adhesive layer opposite to the insulating layer,

the insulating layer contains a resin powder containing a fluororesin,

the resin powder includes particles having a particle diameter of 10 [ mu ] m or more, and does not include particles having a particle diameter exceeding the total thickness of the insulating layer and the adhesive layer,

the surface of the insulating layer on which the adhesive layer is provided has a surface roughness of 0.5 to 3.0 μm.

[2] The metal laminated plate according to [1], wherein the content of the particles having a particle diameter of 10 μm or more in the insulating layer is 5 to 18 vol%.

[3] The metal laminated plate according to [1] or [2], wherein the resin powder further comprises particles having a particle diameter of less than 10 μm, and the content of the particles having a particle diameter of 10 μm or more is 8 to 63% by volume and the content of the particles having a particle diameter of less than 10 μm is 37 to 92% by volume, based on the total volume (100% by volume) of the particles having a particle diameter of 10 μm or more and the particles having a particle diameter of less than 10 μm.

[4] The metal laminated plate according to any one of [1] to [3], wherein the fluororesin is a fluorine-containing copolymer having a melting point of 260 to 320 ℃ and comprising a unit (1) containing at least 1 functional group selected from a carbonyl group-containing group, a hydroxyl group, an epoxy group and an isocyanate group, and a tetrafluoroethylene-based unit (2).

[5] The metal laminated plate according to [4], wherein the fluorine-containing copolymer further comprises a perfluoro (alkyl vinyl ether) -based unit (3-1), and the proportion of the unit (1) is 0.01 to 3 mol%, the proportion of the unit (2) is 90 to 99.89 mol%, and the proportion of the unit (3-1) is 0.1 to 9.99 mol% based on the total of all the units.

[6] The metal laminated plate according to [4] or [5], wherein the fluorine-containing copolymer further comprises a hexafluoropropylene-based unit (3-2), and the proportion of the unit (1) is 0.01 to 3 mol%, the proportion of the unit (2) is 90 to 99.89 mol%, and the proportion of the unit (3-2) is 0.1 to 9.99 mol%, based on the total of all the units.

[7] The metal laminated plate according to any one of the above [4] to [6], wherein the unit (1) has a unit containing a carbonyl group, and the carbonyl group is at least 1 selected from the group consisting of a group having a carbonyl group between carbon atoms of a hydrocarbon group, a carbonate group, a carboxyl group, an acid halide group, an alkoxycarbonyl group, and an acid anhydride residue.

[8] The metal laminated plate according to any one of [1] to [7], wherein the insulating layer and the adhesive layer each have a relative dielectric constant of 2.1 to 3.5.

[9] The metal laminated plate according to any one of [1] to [8], wherein the insulating layer further contains polyimide.

[10] A method for producing a metal laminated plate according to any one of [1] to [9], wherein the insulating layer is formed using a resin powder, and a conductive layer is laminated on at least one surface of the insulating layer in a thickness direction thereof via an adhesive layer; the resin powder contains a fluororesin, and includes particles having a particle diameter of 10 [ mu ] m or more, and does not include particles having a particle diameter exceeding the total thickness of the insulating layer and the adhesive layer.

[11] The method for producing a metal laminated plate according to [10], wherein a resin powder obtained by mixing a resin powder (α) having a particle size peak of 10 to 100 μm and a resin powder (β) having a particle size peak of 0.3 to 8 μm is used.

[12] The method for producing a metal laminated plate according to [10] or [11], wherein at least one of the resin powder (α) and the resin powder (β) is a fluorine-containing copolymer having a melting point of 260 to 320 ℃ and a unit (1) having at least 1 functional group selected from a carbonyl-containing group, a hydroxyl group, an epoxy group, and an isocyanate group, and a tetrafluoroethylene-based unit (2).

[13] The method for producing a metal laminated plate according to any one of [10] to [12], wherein the insulating layer is formed using a dispersion liquid in which the resin powder is dispersed in a liquid medium.

[14] A method for manufacturing a printed board, wherein the conductive layer of the metal laminated plate according to any one of [1] to [9] is etched to form a pattern circuit, thereby obtaining a printed board.

[15] An insulating layer comprising a resin powder containing a fluororesin, wherein the resin powder in the insulating layer comprises at least one of particles having a particle diameter of 10 [ mu ] m or more and aggregates having a particle diameter of 10 [ mu ] m or more, and the content of the particles and aggregates is 5 to 18 vol% based on the total volume of materials forming the insulating layer.

[16] The insulating layer according to [15], wherein the resin powder further comprises particles having a particle diameter of less than 10 μm, and the content of the particles having a particle diameter of 10 μm or more and the aggregates having a particle diameter of 10 μm or more is 8 to 63% by volume, and the content of the particles having a particle diameter of less than 10 μm is 37 to 92% by volume, based on the total volume (100% by volume) of the particles having a particle diameter of 10 μm or more and the aggregates having a particle diameter of less than 10 μm.

[17] The insulating layer according to [15] or [16], wherein the fluororesin is a fluorine-containing copolymer having a unit containing at least 1 functional group selected from a carbonyl group-containing group, a hydroxyl group, an epoxy group and an isocyanate group, and a tetrafluoroethylene-based unit, and having a melting point of 260 to 320 ℃.

[18] The insulating layer according to any one of claims 15 to 17, wherein the relative dielectric constant is 2.1 to 3.5.

[19] A method for producing an insulating layer according to any one of [15] to [18], wherein the insulating layer is formed using a dispersion liquid in which a resin powder (α) having a particle size peak of 10 to 100 μm and a resin powder (β) having a particle size peak of 0.3 to 8 μm are mixed and dispersed in a liquid medium.

[20] A metal laminate comprising an insulating layer, an adhesive layer provided on at least one surface of the insulating layer in a thickness direction thereof, and a conductive layer provided on a surface of the adhesive layer opposite to the insulating layer, wherein the insulating layer is any one of the insulating layers [15] to [18], and does not include any one of particles having a particle diameter exceeding a total thickness of the insulating layer and the adhesive layer and aggregates having a particle diameter of 10 μm or more.

ADVANTAGEOUS EFFECTS OF INVENTION

The metal laminated plate of the present invention can obtain sufficient adhesion strength between the insulating layer and the adhesive layer and between the adhesive layer and the conductive layer while ensuring excellent electrical characteristics.

The method for producing a metal laminated plate of the present invention can produce a metal laminated plate which can secure excellent electrical characteristics and can obtain sufficient adhesion strength between the insulating layer and the adhesive layer and between the adhesive layer and the conductive layer.

By the method for manufacturing a printed circuit board of the present invention, a printed circuit board can be manufactured in which excellent electrical characteristics are ensured and sufficient adhesion strength can be obtained between the insulating layer and the adhesive layer and between the adhesive layer and the conductive layer.

Drawings

Fig. 1 is a schematic cross-sectional view showing an example of the metal laminated plate of the present invention.

Fig. 2 is a schematic cross-sectional view showing another example of the metal laminated plate of the present invention.

Detailed Description

The following terms in the present specification have the following meanings.

The "surface roughness" is the arithmetic average roughness of the surface of the coating film obtained by measuring the level difference of the surface of the coating film by Surfcorder (model ET200, manufactured by Xiaozhan research Co., Ltd.) as a level difference meter.

The "relative dielectric constant" is a value measured at a frequency of 2.5GHz in an environment of 23 ℃ plus or minus 2 ℃ and 50 plus or minus 5% RH by the SPDR (split dielectric resonator) method.

The "average particle diameter of the resin powder" is a volume-based cumulative 50% diameter (D50) obtained by a laser diffraction/scattering method. That is, the particle size distribution was measured by a laser diffraction scattering method, and a cumulative curve was obtained with the total volume of all particles as 100%, and the particle size of a point where the cumulative volume reached 50% on the cumulative curve was obtained.

The "volume-based cumulative 90% diameter (D90) of the resin powder" refers to a volume-based cumulative 90% diameter obtained by a laser diffraction/scattering method. That is, the particle size distribution was measured by a laser diffraction scattering method, and a cumulative curve was obtained with the total volume of all particles as 100%, and the particle size of a point on the cumulative curve where the cumulative volume reached 90%.

"capable of melt-forming" means exhibiting melt fluidity.

The term "exhibits melt fluidity" means that the melt flow rate is 0.1 to 1000g/10 min at a temperature higher than the melting point of the resin by 20 ℃ or more under a load of 49N.

The "melt flow rate" is JIS K7210: the melt Mass Flow Rate (MFR) specified in 1999(ISO 1133: 1997).

"Unit" in a polymer refers to a radical derived from 1 molecule of a monomer formed by polymerization of the monomer. The unit may be a radical formed directly by polymerization, or a radical in which a part of the radical is converted into another structure by treating a polymer obtained by polymerization.

"(meth) acrylate" refers to the generic term acrylate and methacrylate. Further, "(meth) acryloyl group" is a generic name of acryloyl group and methacryloyl group.

The "heat-resistant resin" is a polymer compound having a melting point of 280 ℃ or higher, or JIS C4003: 2010(IEC 60085: 2007) is defined as a polymer compound having a maximum continuous use temperature of 121 ℃ or higher.

[ Metal laminated plate ]

The metal laminate of the present invention includes an insulating layer, an adhesive layer provided on at least one surface of the insulating layer in a thickness direction thereof, and a conductive layer made of a metal provided on a surface of the adhesive layer opposite to the insulating layer. The adhesive layer and the conductive layer in the metal laminated plate of the present invention may be provided only on one surface in the thickness direction of the insulating layer, or may be provided on both surfaces in the thickness direction of the insulating layer. The laminated structure of the metal laminated plate of the present invention includes, for example, a laminated structure in which an insulating layer, an adhesive layer, and a conductive layer are laminated in this order (also referred to as "insulating layer/adhesive layer/conductive layer", the same applies hereinafter), and a conductive layer/adhesive layer/insulating layer/adhesive layer/conductive layer.

As the insulating layer, for example, a film or a fiber-reinforced film can be used. The resin used for the film may be a thermoplastic resin or a cured product of a thermosetting resin, but a heat-resistant resin is preferred.

Examples of the heat-resistant resin include polyimide (e.g., aromatic polyimide), polyacrylate, polysulfone, polyallylsulfone (e.g., polyethersulfone), aromatic polyamide, aromatic polyetheramide, polyphenylene sulfide, polyallylether ketone, polyamideimide, liquid crystal polyester, epoxy resin, acrylic resin, phenol resin, polyester resin, bismaleimide resin, polyolefin resin, modified polyphenylene ether resin, and fluororesin. Among them, polyimide is preferable as the heat-resistant resin. The heat-resistant resin may be used alone in 1 kind, or 2 or more kinds.

The resin for forming a film preferably has a reactive group (i i) that reacts with a functional group (i) described later, among the above resins. Examples of the reactive group (ii) include a carbonyl group-containing group, a hydroxyl group, an amino group, and an epoxy group.

As the insulating layer, a polyimide film is particularly preferably used.

The fiber-reinforced film is a film comprising a reinforced fiber base material and a cured product of a thermoplastic resin or a thermosetting resin.

Examples of the reinforcing fibers used for the fiber-reinforced film include glass fibers, aramid fibers, and carbon fibers. The reinforcing fibers may be surface-treated reinforcing fibers. The reinforcing fibers may be used alone in 1 kind, or in combination of 2 or more kinds.

The form of the reinforcing fiber base material is preferably a base material processed into a sheet form in view of mechanical properties of the fiber-reinforced film. Specifically, for example, a woven fabric obtained by weaving reinforcing fiber bundles composed of a plurality of kinds of reinforcing fibers, a base material obtained by stretching a plurality of kinds of reinforcing fibers in one direction, a base material obtained by stacking these, and the like can be cited. The reinforcing fibers need not be continuous over the entire length in the longitudinal direction or the entire width in the width direction of the reinforcing fiber sheet, and may be divided at intermediate points.

In the present invention, the insulating layer contains resin powder. Specifically, for example, the insulating layer is a film containing resin powder.

The resin powder must contain a fluororesin, and may contain a resin other than a fluororesin as necessary.

The fluororesin forming the resin powder is not particularly limited, and examples thereof include polytetrafluoroethylene (hereinafter referred to as "PTFE"), tetrafluoroethylene (hereinafter referred to as "TFE")/fluoroalkyl vinyl ether copolymers, TFE/hexafluoropropylene copolymers, ethylene/TFE copolymers, and the like. As the fluororesin forming the resin powder, 1 kind or 2 or more kinds may be used alone.

The fluororesin forming the resin powder preferably has at least 1 functional group (hereinafter, also referred to as "functional group (i)") selected from a carbonyl group-containing group, a hydroxyl group, an epoxy group and an isocyanate group from the viewpoint of adhesiveness, and more preferably a fluorine-containing copolymer (X) (hereinafter, also referred to as polymer (X)) having a functional group (i) unit (1) and a TFE-based unit (hereinafter, also referred to as "TFE unit") and having a melting point of 260 to 320 ℃.

The polymer (X) may further contain a unit (1) and a unit other than a TFE unit, if necessary. As the unit other than the unit (1) and the TFE unit, a perfluoro unit such as a PAVE unit or an HFP unit described later is preferable.

The carbonyl group-containing group in the functional group (i) is not particularly limited as long as it has a carbonyl group (-C (═ O) -) in the structure, and examples thereof include a group having a carbonyl group between carbon atoms of a hydrocarbon group, a carbonate group, a carboxyl group, an acid halide group, an alkoxycarbonyl group, an acid anhydride residue, a polyfluoroalkoxycarbonyl group, and a fatty acid residue. Among them, from the viewpoint of improving mechanical pulverizability and improving adhesiveness, a group having a carbonyl group between carbon atoms of a hydrocarbon group, a carbonate group, a carboxyl group, an acid halide group, an alkoxycarbonyl group, or an acid anhydride residue is preferable, and a carboxyl group or an acid anhydride residue is more preferable.

Examples of the hydrocarbon group in the group having a carbonyl group between carbon atoms of the hydrocarbon group include an alkylene group having 2 to 8 carbon atoms. The number of carbon atoms in the alkylene group is the number of carbon atoms in a portion other than the carbonyl group in the alkylene group. The alkylene group may be linear or branched.

The acid halide group is a group represented by — C (═ O) -X (wherein X is a halogen atom). The halogen atom in the acid halide group may, for example, be a fluorine atom or a chlorine atom, and preferably a fluorine atom. That is, as the acid halide group, an acid fluoride group (also referred to as a fluorinated carbonyl group) is preferable.

The alkoxy group in the alkoxycarbonyl group may be linear or branched. The alkoxy group is preferably an alkoxy group having 1 to 8 carbon atoms, and particularly preferably a methoxy group or an ethoxy group.

As the unit (1), a unit based on a monomer having a functional group (i) (hereinafter, also referred to as "monomer (m 1)") is preferable. The number of the functional group (i) of the monomer (m1) may be 1, or 2 or more. In the case where the monomer (m1) has 2 or more functional groups (i), these functional groups (i) may be respectively the same or different.

The monomer (m1) is preferably a compound having 1 functional group (i) and 1 polymerizable double bond.

The monomer (m1) may be used alone in 1 kind, or may be used in combination of 2 or more kinds.

Among the monomers (m1), examples of the monomer having a carbonyl group-containing group include monomers having an acid anhydride residueA cyclic hydrocarbon compound having a group and a polymerizable unsaturated bond (hereinafter, also referred to as "monomer (m 11)"), a monomer having a carboxyl group (hereinafter, also referred to as "monomer (m 12)"), a vinyl ester, (meth) acrylic ester, CF₂＝CFOR^f1COOX¹(wherein, R^f1Is a C1-10 perfluoroalkylene group containing an etheric oxygen atom, X¹Is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. ) And the like.

Examples of the monomer (m11) may include anhydrides of unsaturated dicarboxylic acids. Examples of the acid anhydride of the unsaturated dicarboxylic acid include itaconic anhydride (hereinafter, also referred to as "IAH"), citraconic anhydride (hereinafter, also referred to as "CAH"), 5-norbornene-2, 3-dicarboxylic anhydride (hereinafter, also referred to as "nadic anhydride"), and maleic anhydride.

Examples of the monomer (m12) include unsaturated dicarboxylic acids such as itaconic acid, citraconic acid, 5-norbornene-2, 3-dicarboxylic acid, and maleic acid; unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid.

Examples of the vinyl ester include vinyl acetate, vinyl chloroacetate, vinyl butyrate, vinyl pivalate, and vinyl benzoate.

Examples of the (meth) acrylate include (polyfluoroalkyl) acrylate and (polyfluoroalkyl) methacrylate.

Examples of the monomer having a hydroxyl group include vinyl esters, vinyl ethers, allyl ethers, compounds having 1 or more hydroxyl groups at the terminal or in the side chain of unsaturated carboxylic acid esters ((meth) acrylate, crotonate, etc.), and unsaturated alcohols. Specifically, it may, for example, be 2-hydroxyethyl (meth) acrylate or 2-hydroxyethyl crotonate, or allyl alcohol.

Examples of the monomer having an epoxy group include unsaturated glycidyl ethers (allyl glycidyl ether, 2-methylallyl glycidyl ether, vinyl glycidyl ether, etc.), unsaturated glycidyl esters (glycidyl acrylate, glycidyl methacrylate, etc.), and the like.

Examples of the monomer having an isocyanate group include 2- (meth) acryloyloxyethyl isocyanate, 2- (2- (meth) acryloyloxyethoxy) ethyl isocyanate, and 1, 1-bis ((meth) acryloyloxymethyl) ethyl isocyanate.

The unit (1) preferably has at least a carbonyl group as the functional group (i) in order to improve mechanical crushability and adhesion to metals. As the monomer (m1), a monomer having a carbonyl group is preferable.

The monomer having a carbonyl group is preferably a monomer (m11) in view of improving thermal stability and adhesiveness. Among them, IAH, CAH or NAH is particularly preferable. When at least 1 selected from the group consisting of IAH, CAH and NAH is used, the fluorocopolymer containing an acid anhydride residue can be easily produced without using a special polymerization method which is necessary when maleic anhydride is used (see Japanese patent application laid-open No. 11-193312). Among them, NAH is preferable in terms of more excellent adhesion to thermoplastic resins and the like.

The polymer (X) may have a unit based on perfluoro (alkyl vinyl ether) (hereinafter, also referred to as "PAVE") (hereinafter, also referred to as "PAVE unit") as the unit (1) and a unit other than the TFE unit.

As PAVE, for example, CF₂＝CFOR^f2(wherein, R^f2Is a perfluoroalkyl group having 1 to 10 carbon atoms which may contain an etheric oxygen atom. ). R^f2The perfluoroalkyl group in ((2) may be linear or branched. R^f2The number of carbon atoms of (2) is preferably 1 to 3.

As CF₂＝CFOR^f2Illustrative examples of the "CF" may include₂＝CFOCF₃、CF₂＝CFOCF₂CF₃、CF₂＝CFOCF₂CF₂CF₃(hereinafter, also referred to as "PPVE"), CF₂＝CFOCF₂CF₂CF₂CF₃、CF₂＝CFO(CF₂)₈F, etc., preferably PPVE.

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

The polymer (X) may have a hexafluoropropylene (hereinafter, also referred to as "HFP") based unit (hereinafter, also referred to as "HFP unit") as a unit (1) and a unit other than the TFE unit.

The polymer (X) may have units other than "PAVE units" and "HFP units" (hereinafter, referred to as "other units") as the units other than the unit (1) and the TFE unit.

Examples of the other units include units based on a fluorine-containing monomer (excluding the monomer (m1), TFE, PAVE, and HFP), and units based on a non-fluorine-containing monomer (excluding the monomer (m 1)).

The fluorine-containing monomer is preferably a fluorine-containing compound having 1 polymerizable double bond, and examples thereof include fluoroolefins such as vinyl fluoride, vinylidene fluoride, trifluoroethylene and chlorotrifluoroethylene (with the exception of TFE and HFP), CF₂＝CFOR^f3SO₂X³(wherein, R^f3Is C1-10 perfluoroalkylene, or C2-10 perfluoroalkylene containing etheric oxygen atom, X³Is a halogen atom or a hydroxyl group. ) CF (C)₂＝CF(CF₂)_pOCF＝CF₂(wherein p is 1 or 2.), CH₂＝CX⁴(CF₂)_qX⁵(wherein, X⁴Is a hydrogen atom or a fluorine atom, q is an integer of 2 to 10, X⁵Is a hydrogen atom or a fluorine atom. ) Perfluoro (2-methylene-4-methyl-1, 3-dioxolane), and the like. These may be used alone in 1 kind, or in 2 or more kinds.

The fluorine-containing monomer is preferably vinylidene fluoride, chlorotrifluoroethylene or CH₂＝CX⁴(CF₂)_qX⁵。

As CH₂＝CX⁴(CF₂)_qX⁵Can be exemplified by CH₂＝CH(CF₂)₂F、CH₂＝CH(CF₂)₃F、CH₂＝CH(CF₂)₄F、CH₂＝CF(CF₂)₃H、CH₂＝CF(CF₂)₄H, etc., preferably CH₂＝CH(CF₂)₄F. Or CH₂＝CH(CF₂)₂F。

The non-fluorine-containing monomer is preferably a non-fluorine-containing compound having 1 polymerizable double bond, and examples thereof include olefins having 3 or less carbon atoms such as ethylene and propylene. These may be used alone in 1 kind, or in 2 or more kinds.

As the monomer (m42), ethylene or propylene is preferable, and ethylene is particularly preferable.

The fluorine-containing monomer and the non-fluorine-containing monomer may be used alone in 1 kind or in combination of 2 or more kinds. Further, the fluorine-containing monomer and the non-fluorine-containing monomer may be used in combination.

The polymer (X) is preferably a copolymer (X-1) or a copolymer (X-2) described later, and particularly preferably a copolymer (X-1).

The copolymer (X-1) comprises a unit (1), a TFE unit and a PAVE unit, and the proportion of the unit (1) to the total of all the units is preferably 0.01 to 3 mol%, the proportion of the TFE unit is 90 to 99.89 mol%, and the proportion of the PAVE unit is 0.1 to 9.99 mol%.

The copolymer (X-1) may further have at least one of HFP unit and other units as required. The copolymer (X-1) may be composed of the unit (1) and TFE units and PAVE units, may be composed of the unit (1) and TFE units and PAVE units and HFP units, may be composed of the unit (1) and TFE units and PAVE units and other units, or may be composed of the unit (1) and TFE units and PAVE units and HFP units and other units.

As the copolymer (X-1), a copolymer having a unit based on a monomer containing a carbonyl group, and a TFE unit, and a PAVE unit is preferable, and a copolymer having a unit based on a monomer (m11), and a TFE unit, and a PAVE unit is particularly preferable. Specific examples of the preferable copolymer (X-1) include TFE/PPVE/NAH copolymer, TFE/PPVE/IAH copolymer, TFE/PPVE/CAH copolymer and the like.

The copolymer (X-1) may have the functional group (i) as an end group. The functional group (i) can be introduced by appropriately selecting a radical polymerization initiator, a chain transfer agent, and the like used in the production of the copolymer (X-1).

The proportion of the unit (1) relative to the total of all units constituting the copolymer (X-1) is 0.01 to 3 mol%, preferably 0.03 to 2 mol%, and particularly preferably 0.05 to 1 mol%. If the content of the unit (1) is not less than the lower limit of the above range, a resin powder having a high bulk density can be easily obtained. Further, the resin powder is excellent in adhesion to a thermoplastic resin or the like, and interlayer adhesion to other substrates (metal or the like) such as a film formed from the dispersion or the liquid composition. When the content of the unit (1) is not more than the upper limit of the above range, the copolymer (X-1) is excellent in heat resistance, color tone and the like.

The proportion of TFE units based on the total of all units constituting the copolymer (X-1) is 90 to 99.89 mol%, preferably 95 to 99.47 mol%, and particularly preferably 96 to 98.95 mol%. When the content of TFE unit is not less than the lower limit of the above range, the copolymer (X-1) is excellent in electric characteristics (low dielectric constant, etc.), heat resistance, chemical resistance, etc. When the content of TFE unit is not more than the upper limit of the above range, the copolymer (X-1) is excellent in melt moldability, stress cracking resistance and the like.

The proportion of PAVE units relative to the total of all units constituting the copolymer (X-1) is 0.1 to 9.99 mol%, preferably 0.5 to 9.97 mol%, and particularly preferably 1 to 9.95 mol%. When the content of PAVE units is within the above range, the copolymer (X-1) is excellent in moldability.

The proportion of the total of the unit (1), the TFE unit, and the PAVE unit relative to the total of all the units in the copolymer (X-1) is preferably 90 mol% or more, more preferably 95 mol% or more, and still more preferably 98 mol% or more. The upper limit of the proportion is not particularly limited, and may be 100 mol%.

The content of each unit in the copolymer (X-1) can be determined by NMR analysis such as melt Nuclear Magnetic Resonance (NMR) analysis, fluorine content analysis, infrared absorption spectrum analysis, or the like. For example, as described in Japanese patent laid-open No. 2007-314720, the proportion (mol%) of the unit (1) in the total units constituting the copolymer (X-1) can be determined by a method such as infrared absorption spectrum analysis.

The copolymer (X-2) is a copolymer comprising the unit (1), a TFE unit and an HFP unit, and preferably has a ratio of 0.01 to 3 mol% of the unit (1), a ratio of the TFE unit of 90 to 99.89 mol% and a ratio of the HFP unit of 0.1 to 9.99 mol% with respect to the total of all the units (except the copolymer (X-1)).

The copolymer (X-2) may further have PAVE units and other units as required. The copolymer (X-2) may be composed of the unit (1) and TFE unit and HFP unit, may be composed of the unit (1) and TFE unit and HFP unit and PAVE unit (except for the copolymer (X-1)), may be composed of the unit (1) and TFE unit and HFP unit and other unit, or may be composed of the unit (1) and TFE unit and HFP unit and PAVE unit and other unit (except for the copolymer (X-1)).

As the copolymer (X-2), a copolymer having a unit based on a monomer containing a carbonyl group, and a TFE unit, and an HFP unit is preferable, and a copolymer having a unit based on a monomer (m11), and a TFE unit, and an HFP unit is particularly preferable. Specific examples of the preferable copolymer (X-2) include TFE/HFP/NAH copolymer, TFE/HFP/IAH copolymer, TFE/HFP/CAH copolymer and the like.

Further, the polymer (X-2) may have a terminal group having the functional group (i) as in the case of the polymer (X-1).

The proportion of the unit (1) relative to the total of all units constituting the copolymer (X-2) is 0.01 to 3 mol%, preferably 0.02 to 2 mol%, particularly preferably 0.05 to 1.5 mol%. If the content of the unit (1) is not less than the lower limit of the above range, a resin powder having a high bulk density can be easily obtained. Further, the resin powder is excellent in adhesion to a thermoplastic resin or the like, and interlayer adhesion to other substrates (metal or the like) such as a film formed from the dispersion or the liquid composition. When the content of the unit (1) is not more than the upper limit of the above range, the copolymer (X-2) is excellent in heat resistance, color tone and the like.

The proportion of TFE units based on the total of all units constituting the copolymer (X-2) is 90 to 99.89 mol%, preferably 91 to 98 mol%, particularly preferably 92 to 96 mol%. When the content of TFE unit is not less than the lower limit of the above range, the copolymer (X-2) is excellent in electric characteristics (low dielectric constant, etc.), heat resistance, chemical resistance, etc. When the content of TFE unit is not more than the upper limit of the above range, the copolymer (X-2) is excellent in melt moldability, stress cracking resistance and the like.

The proportion of the HFP unit relative to the total of all units constituting the copolymer (X-2) is 01 to 9.99 mol%, preferably 1 to 9 mol%, and particularly preferably 2 to 8 mol%. If the content of HFP units is within the above range, the copolymer (X-2) is excellent in moldability.

The proportion of the total of the unit (1), the TFE unit, and the HFP unit relative to the total of all the units in the copolymer (X-2) is preferably 90 mol% or more, more preferably 95 mol% or more, and still more preferably 98 mol% or more. The upper limit of the proportion is not particularly limited, and may be 100 mol%.

The melting point of the polymer (X) is preferably 260 to 320 ℃, more preferably 280 to 320 ℃, further preferably 295 to 315 ℃, and particularly preferably 295 to 310 ℃. When the melting point of the polymer (X) is not less than the lower limit of the above range, the heat resistance is excellent. When the melting point of the polymer (X) is not more than the upper limit of the above range, the melt-moldability is excellent.

The melting point of the polymer (X) can be adjusted by the kind, content ratio, molecular weight, and the like of the unit constituting the polymer (X). For example, the higher the proportion of TFE units, the higher the melting point tends to be.

The polymer (X) is preferably melt-formable.

The Melt Flow Rate (MFR) of the polymer (X) is preferably 0.1 to 1000g/10 min, more preferably 0.5 to 100g/10 min, still more preferably 1 to 30g/10 min, particularly preferably 5 to 20g/10 min. When the MFR is not less than the lower limit of the above range, the polymer (X) is excellent in moldability, and a film or the like formed using the dispersion or the liquid composition is excellent in surface smoothness and appearance. If the MFR is not more than the upper limit of the above range, the polymer (X) is excellent in mechanical strength, and a film or the like formed using the dispersion or the liquid composition is excellent in mechanical strength.

MFR is an index of the molecular weight of the copolymer (X), and is expressed in that the larger the MFR, the smaller the molecular weight, and the smaller the MFR, the larger the molecular weight. The molecular weight or MFR of the polymer (X) can be adjusted by the production conditions of the polymer (X). For example, when the polymerization time is shortened in the polymerization of the monomer, the MFR tends to be increased.

The relative dielectric constant of the polymer (X) is preferably 2.5 or less, more preferably 2.4 or less, and particularly preferably 2.0 to 2.4. The lower the relative dielectric constant of the polymer (X), the more excellent the electrical characteristics of a film formed using the dispersion or liquid composition, and the excellent transmission efficiency can be obtained when the film is used as a substrate for a printed circuit board, for example.

The relative dielectric constant of the polymer (X) can be adjusted by the content of TFE units.

The polymer (X) can be produced by a conventional method. Examples of the method for producing the polymer (X) include the methods described in International publication Nos. 2016/017801 [0053] to [0060 ].

The resin other than the fluororesin is not particularly limited as long as the electrical reliability is not impaired, and examples thereof include aromatic polyesters, polyamideimides, and thermoplastic polyimides. As other resins, 1 kind or more may be used alone or 2 or more kinds may be used.

The resin powder preferably contains a fluororesin as a main component, and more preferably contains the polymer (X) as a main component. If the polymer (X) is the main component, a resin powder having a high bulk density can be easily obtained. The larger the bulk density of the resin powder is, the more excellent the handling property is. The phrase "the polymer (X) is a main component" in the resin powder means that the proportion of the polymer (X) to the total amount (100 mass%) of the resin powder is 80 mass% or more. The proportion of the polymer (X) relative to the total amount (100 mass%) of the resin powder is preferably 85 mass% or more, more preferably 90 mass% or more, and particularly preferably 100 mass%.

The resin powder includes particles having a particle diameter of 10 μm or more (hereinafter, also referred to as "particles (a)"), and does not include particles having a particle diameter exceeding the total thickness of the insulating layer and the adhesive layer. When the resin powder includes the particles (a), the surface of the insulating layer is appropriately thickened, and an anchor effect is exhibited between the insulating layer and the adhesive layer, whereby the adhesive strength between the layers is improved. Further, by not including particles having a particle diameter exceeding the total thickness of the insulating layer and the adhesive layer, the resin powder is inhibited from reaching the interlayer between the adhesive layer and the conductive layer. In this way, adhesion between the adhesive layer and the conductive layer is inhibited from being inhibited by the resin powder containing the fluororesin, and therefore sufficient adhesion strength between the layers can be obtained.

In the case where the adhesive layers are provided on both surfaces of the insulating layer, "the total thickness of the insulating layer and the adhesive layer" in the "particles having a particle diameter exceeding the total thickness of the insulating layer and the adhesive layer" means the sum of the thickness of the insulating layer and the thickness of one adhesive layer. When adhesive layers having different thicknesses are provided on both surfaces of the insulating layer, the thickness of the adhesive layer having a smaller thickness is used as a reference.

The particle diameter of the particles (A) is 10 [ mu ] m or more and does not exceed the total thickness of the insulating layer and the adhesive layer. The upper limit of the particle diameter of the particles (A) can be suitably set in accordance with the total thickness of the insulating layer and the adhesive layer, and is preferably 100 μm, more preferably 80 μm, and still more preferably 40 μm.

In view of excellent dispersion stability in a liquid in a process for producing a film, the resin powder preferably includes particles (hereinafter, also referred to as "particles (B)") having a particle diameter of less than 10 μm in addition to the particles (a). The lower limit of the particle (B) is preferably 0.01. mu.m, more preferably 0.1. mu.m.

The content of the resin powder in the insulating layer is preferably 5 to 80 vol%, more preferably 7 to 50 vol%, and still more preferably 10 to 45 vol% with respect to the total volume of the material forming the insulating layer. If the content of the resin powder is not less than the lower limit of the above range, excellent electrical characteristics are easily obtained, and an anchor effect is easily exhibited between the insulating layer and the adhesive layer. If the content of the resin powder is not more than the upper limit of the above range, a sufficient strength of the film can be obtained while suppressing a decrease in mechanical strength such as tensile strength of the film at room temperature and at heating.

The content of the particles (a) in the insulating layer is preferably 5 to 18 vol%, more preferably 6 to 15 vol%, based on the total volume of the material forming the insulating layer. When the content of the particles (a) is not less than the lower limit of the above range, excellent electrical characteristics are easily obtained, and an anchor effect is easily exhibited between the insulating layer and the adhesive layer. If the content of the particles (a) is not more than the upper limit of the above range, a decrease in mechanical strength such as tensile strength of the film at room temperature and at heating can be suppressed, and a film having sufficient strength can be obtained.

When the resin powder includes the particles (a) and the particles (B), the content of the particles (a) is preferably 8 to 63 vol%, the content of the particles (B) is preferably 37 to 92 vol%, the content of the particles (a) is more preferably 8 to 60 vol%, the content of the particles (B) is more preferably 40 to 92 vol%, the content of the particles (a) is more preferably 13 to 55 vol%, and the content of the particles (B) is more preferably 45 to 87 vol%. The total volume of the particles (a) and (B) was 100 vol%.

Further, the insulating layer includes particles (a) having a particle diameter of 10 μm or more, but may include aggregates having a particle diameter of 10 μm or more together with or instead of the particles (a). The aggregate is a structure in which a plurality of particles are aggregated, and is a structure in which 2 or more particles are closely aggregated when the insulating layer is cut and observed with a scanning electron microscope. However, when the surface roughness of the insulating layer is not defined to be 0.5 to 3.0 μm, the total of the particles (a) and aggregates having a particle diameter of 10 μm or more included in the insulating layer is 5 to 18% by volume based on the total volume of the material forming the insulating layer.

As a method for producing the resin powder, for example, a method may be mentioned in which a fluororesin-containing powder material is pulverized and classified (e.g., sieved) as necessary to obtain a resin powder including the particles (a) excluding particles having a particle diameter exceeding the total thickness of the insulating layer and the adhesive layer. In the case of producing a fluororesin by solution polymerization, suspension polymerization or emulsion polymerization, the organic solvent or aqueous medium used in the polymerization is removed, and the particulate fluororesin is recovered and then pulverized or classified (e.g., sieved). In the case where the fluororesin obtained by polymerization contains the particles (a) and does not contain particles having a particle diameter exceeding the total thickness of the insulating layer and the adhesive layer, the fluororesin may be used as it is as a resin powder. When 2 or more kinds of resins are used as the powder material, it is preferable to melt and knead these resins, and then crush and classify them.

Further, 2 or more kinds of resin powders having different particle size distributions may be mixed.

As a method for pulverizing and classifying the powder material, the methods described in International publication Nos. 2016/017801 [0065] to [0069] can be used. Further, as the resin powder, a desired resin powder may be used if it is commercially available.

The surface roughness of the side of the insulating layer where the adhesive layer is provided is 0.5 to 3.0 μm, preferably 0.5 to 2.5 μm, and more preferably 0.5 to 2.0 μm. If the surface roughness is not less than the lower limit of the above range, the anchor effect is sufficiently exhibited between the insulating layer and the adhesive layer, and a sufficient adhesive strength can be obtained. If the surface roughness is not more than the upper limit of the above range, a decrease in mechanical strength such as tensile strength of the film at room temperature and at heating can be suppressed, and a film having sufficient strength can be obtained.

The insulating layer may contain known additives as needed. Examples of the additive include fillers. The insulating layer contains a filler, whereby the dielectric constant and the dielectric loss tangent of the insulating layer can be reduced. The filler is preferably an inorganic filler, and examples thereof include inorganic fillers described in [0089] of International publication No. 2016/017801. The inorganic filler may be used alone in 1 kind, or may be used in combination of 2 or more kinds.

When the insulating layer contains a filler, the content of the filler in the insulating layer is preferably 0.1 to 300 parts by mass, more preferably 1 to 200 parts by mass, even more preferably 3 to 150 parts by mass, particularly preferably 5 to 100 parts by mass, and most preferably 10 to 60 parts by mass, based on 100 parts by mass of the resin powder. The more the content of the filler, the lower the coefficient of linear expansion (CTE) of the insulating layer becomes, and the better the thermal dimensional property of the insulating layer becomes.

The thickness of the insulating layer is preferably 4 to 1000. mu.m, more preferably 6 to 300. mu.m, and particularly preferably 7 to 50 μm. If the thickness of the insulating layer is not less than the lower limit of the above range, the printed circuit board is less likely to be excessively deformed, and thus the conductive layer is less likely to be broken. If the thickness of the insulating layer is not more than the upper limit of the above range, the flexibility is excellent and the reduction in size and weight of the printed board can be coped with.

The relative dielectric constant of the insulating layer is preferably 2.1 to 3.5, particularly preferably 2.1 to 3.3. If the relative dielectric constant of the insulating layer is not more than the upper limit of the above range, it is useful for a printed circuit board requiring a low dielectric constant. When the relative permittivity is not less than the lower limit of the above range, both the electrical characteristics and the adhesiveness are excellent.

Examples of the material for forming the adhesive layer include thermoplastic resins. Among them, thermoplastic polyimide (hereinafter, also referred to as "TPI") is preferable. As the material for forming the adhesive layer, 1 kind or 2 or more kinds may be used alone.

The thickness of the adhesive layer is preferably 3 to 100 μm, more preferably 3 to 50 μm. When the thickness of the adhesive layer is not less than the lower limit of the above range, the adhesive strength with the conductive layer and the insulating layer is excellent. If the thickness of the adhesive layer is not more than the upper limit of the above range, the electrical characteristics are excellent.

In the case where the adhesive layers are formed on both sides of the insulating layer, the composition and thickness of each adhesive layer may be the same or different. In order to easily suppress warpage, the composition and thickness of each adhesive layer are preferably the same.

The relative dielectric constant of the adhesive layer is preferably 2.1 to 3.5, particularly preferably 2.1 to 3.0. If the relative dielectric constant of the adhesive layer is not more than the upper limit of the above range, it is useful for a printed circuit board requiring a low dielectric constant. When the relative permittivity is not less than the lower limit of the above range, both the electrical characteristics and the adhesiveness are excellent.

The metal forming the conductive layer may be appropriately selected according to the application, and examples thereof include copper, a copper alloy, stainless steel, and an alloy thereof. As the conductive layer, a metal foil is preferably used, and a copper foil such as a rolled copper foil or an electrolytic copper foil is more preferred. A rust-proof layer (e.g., an oxide film of chromate or the like) or a heat-resistant layer may be formed on the surface of the metal foil. In addition, in order to improve adhesion to the adhesive layer, the surface of the metal foil may be subjected to a coupling agent treatment or the like.

The thickness of the conductive layer is not particularly limited as long as it is selected to sufficiently function according to the use of the metal laminate, and is preferably 0.1 to 50 μm, more preferably 1 to 25 μm, and still more preferably 2 to 25 μm.

An example of the embodiment of the metal laminated plate of the present invention is a metal laminated plate 1 illustrated in fig. 1. The metal laminated plate 1 includes an insulating layer 10, an adhesive layer 12 provided on one surface 10a in the thickness direction of the insulating layer 10, and a conductive layer 14 provided on the opposite side of the adhesive layer 12 from the insulating layer 10.

The insulating layer 10 contains a resin powder 16 containing particles (a)16a and particles (B) 16B. In the surface 10a of the insulating layer 10 on the adhesive layer 12 side, a part of the resin powder 16 partially protrudes. Thus, the surface roughness of the surface 10a of the insulating layer 10 is 0.5 to 3.0 μm.

The resin powder 16 does not include particles having a particle diameter exceeding the total thickness d1+ d2(μm) of the insulating layer 10 and the adhesive layer 12.

Another embodiment of the metal laminated plate according to the present invention may be, for example, a metal laminated plate 2 illustrated in fig. 2. The metal laminated plate 2 includes an insulating layer 20, a first adhesive layer 22 provided on one surface 20a in the thickness direction of the insulating layer 20, a first conductive layer 24 provided on the first adhesive layer 22 on the side opposite to the insulating layer 20, a second adhesive layer 26 provided on the other surface 20b in the thickness direction of the insulating layer 20, and a second conductive layer 28 provided on the second adhesive layer 26 on the side opposite to the insulating layer 20.

The insulating layer 20 contains a resin powder 30 containing particles (a)30a and particles (B) 30B. In both surfaces 20a, 20b of the insulating layer 20, a part of the resin powder 30 partially protrudes, respectively. Thus, the surface roughness of the surface 20a and the surface 20b of the insulating layer 20 are 0.5 to 3.0 μm, respectively.

The resin powder 30 does not include particles having a particle diameter exceeding the smaller value of the total thickness d3+ d4 of the insulating layer 20 and the first adhesive layer 22 or the total thickness d3+ d5 of the insulating layer 20 and the second adhesive layer 26.

In the metal laminated plate of the present invention described above, the insulating layer contains a resin powder containing a fluororesin. Therefore, the dielectric constant and the dielectric loss tangent are low, and the electric characteristics are excellent.

Further, at least a part of the particles (A) contained in the resin powder partially protrude on the surface of the insulating layer on the adhesive layer side, so that the surface roughness of the insulating layer on the adhesive layer side is 0.5 to 3.0 [ mu ] m. Thereby, the interlayer of the insulating layer and the adhesive layer exhibits an anchoring effect, and the adhesive strength between the insulating layer and the adhesive layer is sufficiently improved.

Further, the adhesive strength between the adhesive layer and the conductive layer is higher than the adhesive strength between the fluororesin-containing resin powder and the conductive layer. Therefore, if the resin powder reaches between the adhesive layer and the conductive layer, adhesion of the adhesive layer and the conductive layer is hindered. However, in the metal laminated plate of the present invention, since the resin powder does not include particles having a particle diameter exceeding the total thickness of the insulating layer and the adhesive layer, the resin powder is prevented from reaching the interlayer between the adhesive layer and the conductive layer. Sufficient adhesion strength can be ensured also between the adhesion layer and the conductive layer.

[ method for producing Metal laminated plate ]

The method for producing the metal laminated plate of the present invention will be described below. The method for producing a metal laminated plate of the present invention includes the following steps 1 and 2.

Step 1: the insulating layer is formed by using a resin powder containing a fluororesin, and including particles (A) having a particle diameter of 10 [ mu ] m or more, and not including particles exceeding the total thickness of the insulating layer and the adhesive layer.

And a step 2: a conductive layer is laminated on at least one surface of the insulating layer in the thickness direction via an adhesive layer.

(step 1)

In step 1, a resin powder is used which includes the particles (a) and does not include particles having a particle diameter exceeding the total thickness of the target insulating layer and the adhesive layer.

The average particle diameter of the resin powder used in step 1 is preferably 0.3 to 25 μm, more preferably 0.5 to 20 μm, still more preferably 1 to 17 μm, and particularly preferably 2 to 15 μm. If the average particle diameter of the resin powder is not less than the lower limit of the above range, the fluidity of the resin powder is sufficient, and the handling is easy. If the average particle diameter of the resin powder is not more than the upper limit of the above range, the dispersibility of the resin powder in a liquid medium is excellent. The smaller the average particle diameter of the resin powder is, the higher the filling ratio of the resin powder to the insulating layer can be, and the more excellent the electrical characteristics (low dielectric constant, etc.) of the insulating layer are. In addition, the printed substrate is easily thinned.

When a resin powder including the particles (a) and (B) is used, it is preferable to use a resin powder in which a powder having a particle size peak of 10 to 100 μm (hereinafter, also referred to as "powder (a)") and a powder having a particle size peak of 0.3 to 8 μm (hereinafter, also referred to as "powder (B)") are mixed. In this case, at least one of the powder (a) and the powder (b) is preferably formed with the polymer (X), and preferably both of the powder (a) and the powder (b) are formed with the polymer (X).

The peak particle size of the powder (a) is 10 to 100. mu.m, preferably 11 to 50 μm, and more preferably 12 to 20 μm. The average particle diameter of the powder (a) is preferably 5 to 30 μm, more preferably 6 to 25 μm, still more preferably 7 to 23 μm, and particularly preferably 8 to 20 μm.

The cumulative 90% diameter (D90) of the powder (a) on a volume basis is preferably 45 μm or less, more preferably 35 μm or less, and particularly preferably 25 μm or less. If D90 of the powder (a) is not more than the upper limit, the dispersibility in a liquid medium is excellent.

The bulk density of the powder (a) is preferably 0.05g/mL or more, more preferably 0.05 to 0.5g/mL, and particularly preferably 0.08 to 0.5 g/mL.

The dense packing bulk density of the powder (a) is preferably 0.05g/mL or more, more preferably 0.05 to 0.8g/mL, and particularly preferably 0.1 to 0.8 g/mL.

The larger the loose packed bulk density or the dense packed bulk density is, the more excellent the handling of the powder (a) is. Further, the filling ratio of the powder (a) into the insulating layer can be improved. If the loose packed bulk density or the dense packed bulk density is below the upper limit of the above range, a general process may be used.

The peak particle size of the powder (b) is 0.3 to 8 μm, preferably 0.4 to 6 μm, and more preferably 0.5 to 5 μm.

The average particle diameter of the powder (b) is preferably 0.3 to 6 μm, more preferably 0.3 to 5 μm, still more preferably 0.3 to 4 μm, and particularly preferably 0.3 to 3 μm.

The cumulative 90% diameter (D90) of the powder (b) on a volume basis is preferably 8 μm or less, more preferably 7 μm or less, and particularly preferably 6 μm or less. If D90 of the powder (b) is not more than the upper limit, the dispersibility in a liquid medium is excellent.

The bulk density of the loose packed powder (b) is preferably 0.05g/mL or more, more preferably 0.05 to 0.5g/mL, and particularly preferably 0.08 to 0.5 g/mL.

The dense packing bulk density of the powder (b) is preferably 0.05g/mL or more, more preferably 0.05 to 0.8g/mL, and particularly preferably 0.1 to 0.8 g/mL.

In step 1, the insulating layer is preferably formed using a dispersion liquid in which a resin powder is dispersed in a liquid medium. Specifically, it is preferable to mix a dispersion liquid containing a resin powder with a liquid containing a resin (hereinafter, also referred to as a "material resin") or a raw material thereof (hereinafter, also referred to as a "resin liquid") used for a film for forming an insulating layer to prepare a liquid composition, and then form the insulating layer using the liquid composition. By mixing the dispersion liquid and the resin liquid, the material resin or the raw material thereof can be easily uniformly dispersed without scattering the resin powder, as compared with the case where the resin powder is mixed with the resin liquid in a powder state. In the production method of the present invention, the resin powder may be mixed with the resin liquid in a powder state to prepare a liquid composition, or the material resin may be mixed with the dispersion liquid to prepare a liquid composition.

The method of mixing the dispersion and the resin liquid is not particularly limited, and for example, a method using a known stirrer may be mentioned. When the liquid composition contains a filler, a curing agent, or the like, these may be added to the dispersion before mixing, to the resin liquid before mixing, or to the mixed liquid after mixing.

As the liquid medium used in the dispersion, a known liquid medium can be used, and examples thereof include water; alcohols such as methanol and ethanol; nitrogen-containing compounds such as N, N-dimethylformamide, N-dimethylacetamide and N-methyl-2-pyrrolidone; sulfur-containing compounds such as dimethyl sulfoxide; ethers such as diethyl ether and dioxane; esters such as ethyl lactate and ethyl acetate; ketones such as methyl ethyl ketone and methyl isopropyl ketone; glycol ethers such as ethylene glycol monoisopropyl ether; cellosolves such as methyl cellosolve and ethyl cellosolve; aromatic compounds such as ethylbenzene, toluene and xylene. The liquid medium may be used alone in 1 kind, or may be used in combination of 2 or more kinds.

The liquid medium does not contain a resin used for forming the film of the insulating layer or a liquid component in a raw material thereof. The liquid medium is a compound that does not react with the polymer (X).

The content of the liquid medium in the dispersion is preferably 1 to 1000 parts by mass, more preferably 10 to 500 parts by mass, and particularly preferably 30 to 250 parts by mass, based on 100 parts by mass of the resin powder. If the content of the liquid medium is within the above range, the coating property at the time of film formation is good. Further, if the content of the liquid medium is not more than the upper limit of the above range, the amount of the liquid medium used is small, and therefore, the appearance of the film-formed product resulting from the liquid medium removal step is not likely to be deteriorated.

The dispersion may also contain a surfactant. The surfactant is not particularly limited, and examples thereof include nonionic surfactants, anionic surfactants, and cationic surfactants. Among them, nonionic surfactants are preferable as the surfactant. The surfactant may be used alone in 1 kind, or may be used in combination of 2 or more kinds.

When the dispersion contains a surfactant, the content of the surfactant in the dispersion is preferably 0.1 to 20 parts by mass, more preferably 0.2 to 10 parts by mass, and particularly preferably 0.3 to 7 parts by mass, based on 100 parts by mass of the resin powder. When the content of the surfactant is not less than the lower limit of the above range, excellent dispersibility can be easily obtained. If the content of the surfactant is less than or equal to the upper limit of the above range, the properties of the resin powder can be obtained without being affected by the properties of the surfactant.

The method for producing the dispersion is not particularly limited, and examples thereof include a method of mixing and stirring the resin powder, a surfactant, a filler and a liquid medium, which are used as needed.

The material resin used in the resin solution is the resin exemplified in the description of the insulating layer.

Examples of the raw material of the material resin include precursors (polyamic acids) of aromatic polyimides, and preferably precursors (polyamic acids) of wholly aromatic polyimides obtained by polycondensation of aromatic polycarboxylic acid dianhydrides and aromatic diamines. Specific examples of the aromatic polycarboxylic acid dianhydride and the aromatic diamine include those described in [0055] and [0057] in Japanese patent laid-open Nos. 2012-145676. These may be used alone in 1 kind, or 2 or more kinds may be used in combination.

As a raw material of the material resin, polyamic acid obtained by polycondensation of a polycarboxylic dianhydride or a derivative thereof and a diamine, which is a raw material precursor of TPI, can be used. Examples of the polycarboxylic acid dianhydride or derivative thereof and the diamine which form the polyamic acid as a raw material of TPI include the polycarboxylic acid dianhydride or derivative thereof and the diamine described in japanese patent nos. 5766125 [0019] and [0020 ].

When the material resin or the raw material thereof is in a liquid state, the material resin or the raw material thereof can be used as it is as the resin solution. When the material resin or the raw material thereof is not in a liquid state, these may be dissolved or dispersed in a liquid medium to prepare a resin liquid. The liquid medium capable of dissolving or dispersing the material resin or the raw material thereof is not particularly limited, and may be appropriately selected from the examples exemplified as the liquid medium in the dispersion liquid, depending on the kind of the material resin or the raw material thereof.

When a thermosetting resin or a raw material thereof is used in the resin liquid, the liquid composition may contain a curing agent. Examples of the curing agent include a thermal curing agent (such as melamine resin and polyurethane resin) and an epoxy curing agent (such as novolak-type phenol resin, isophthalic dihydrazide and adipic dihydrazide).

The content of the liquid medium in the liquid composition is preferably 1 to 1000 parts by mass, more preferably 10 to 500 parts by mass, and particularly preferably 30 to 250 parts by mass, based on 100 parts by mass of the total of the resin powder and the raw material resin or the raw material thereof. If the content of the liquid medium is not less than the lower limit of the above range, the viscosity of the liquid composition is not excessively high, and the coating property during film formation is good. If the content of the liquid medium is not more than the upper limit of the above range, the viscosity of the liquid composition is not excessively low, the coating property at the time of film formation is good, and the appearance of the film-formed product resulting from the removal step of the liquid medium is less likely to be defective because the amount of the liquid medium used is small.

In the case where the liquid medium is contained in the resin liquid, the content of the liquid medium in the liquid composition refers to the total content of the liquid medium of the dispersion liquid and the liquid medium of the resin liquid.

When the liquid composition contains a curing agent, the content of the curing agent in the liquid composition is preferably 0.5 to 2.0 equivalents, more preferably 0.8 to 1.2 equivalents, relative to the amount of the reactive group contained in the thermosetting resin or the raw material thereof.

As a method for forming an insulating layer using a liquid composition, when an insulating layer is formed using a film, for example, a method in which a film is formed using a liquid composition, dried, and then heated to obtain a film can be mentioned.

The method for forming a film of the liquid composition is not particularly limited, and examples thereof include a known wet coating method such as a spray coating method, a roll coating method, a spin coating method, and a bar coating method, and a method of applying the liquid composition to a flat surface.

After the film formation of the liquid composition, at least a part of the liquid medium is removed by drying. During the drying, it is not always necessary to completely remove the liquid medium, and the drying may be performed until the film formed on the substrate can be stably maintained in the film shape. In the drying, it is preferable to remove 50 mass% or more of the liquid medium contained in the liquid composition.

The method of drying the coating film after film formation is not particularly limited, and examples thereof include a method of heating in an oven, a method of heating in a continuous drying furnace, and the like.

The drying temperature may be within a range in which no foaming occurs when the liquid medium is removed, and is, for example, preferably 50 to 250 ℃, and more preferably 70 to 220 ℃. The drying time is preferably 0.1 to 30 minutes, more preferably 0.5 to 20 minutes. The drying may be carried out in one stage, or may be carried out in two or more stages at different temperatures.

When a raw material of a thermoplastic resin is used in the resin solution, the raw material of the thermoplastic resin is heated after drying to be a thermoplastic resin. For example, when a polyamic acid is used as a raw material of TPI, the polyamic acid is imidized by heating after drying to obtain TPI. In this case, the heating temperature after drying may be set to 350 to 550 ℃.

When a thermosetting resin is used in the resin solution, the thermosetting resin is cured by heating after drying. In the case of using a raw material of a thermosetting resin (e.g., polyamic acid which is a precursor of aromatic polyimide), the raw material of the thermosetting resin is made into the thermosetting resin by heating after drying, and is further cured. The heating temperature after drying may be appropriately set according to the kind of the thermosetting resin, and for example, in the case of using an epoxy resin, the heating temperature may be set to 50 to 250 ℃. The drying and subsequent heating may also be carried out continuously.

In the case of forming the insulating layer with a fiber-reinforced film, a method of impregnating a reinforcing fiber base material with a liquid composition, drying the composition, and then heating the composition to obtain a fiber-reinforced film may be mentioned.

Specifically, the liquid composition is impregnated into the reinforcing fiber base material, and then dried to remove at least a part of the liquid medium, followed by further heating. The drying and heating after the impregnation can be performed in the same manner as in the above-described film production method.

Alternatively, the liquid composition may be impregnated into a reinforcing fiber base material, and dried to prepare a prepreg. Impregnation of the reinforcing fiber base material with the liquid composition in the production of the prepreg can be performed in the same manner as in the production method of the fiber-reinforced film.

The drying after impregnation can be performed in the same manner as the drying in the film production method. The prepreg may contain a liquid medium. In the prepreg, it is preferable to remove 70 mass% or more of the liquid medium contained in the liquid composition. In the case of using a liquid composition containing a thermosetting resin or a raw material of a thermosetting resin in the prepreg, the curable resin may be made into a semi-cured state after drying.

The prepreg can be used as a material for sheet piles which are required to have durability and lightweight in wharf engineering, or a material for members for various applications such as aircrafts, automobiles, ships, windmills, and sports equipment (japanese patent スポー appliances), in addition to printed boards.

(step 2)

As a method of laminating a conductive layer on one surface or both surfaces of an insulating layer via an adhesive layer, for example, a method of laminating an insulating layer and a metal foil by heat lamination using a material for forming an adhesive layer such as TPI is exemplified. Alternatively, a method may be used in which a liquid in which a material for forming an adhesive layer such as TPI is dispersed or dissolved is applied to one or both of the surface of the insulating layer and the surface of the metal foil, and after drying, these are stacked so that the coating films face each other, and heat-pressed.

[ method for producing printed substrate ]

The method for manufacturing a printed circuit board of the present invention is a method for obtaining a printed circuit board by etching the conductive layer of the metal laminated plate of the present invention described above to form a pattern circuit. Thus, by using the metal laminated plate of the present invention, a printed board can be manufactured. The metal layer may be etched by a known method.

In the method for manufacturing a printed circuit board according to the present invention, after the metal layer is etched to form the pattern circuit, the interlayer insulating film may be formed on the pattern circuit, and the pattern circuit may be further formed on the interlayer insulating film. The interlayer insulating film can be formed by, for example, the liquid composition obtained by the production method of the present invention.

Specifically, the following methods may be mentioned. After the conductive layer of the metal laminated plate is etched to form a pattern circuit, the liquid composition is applied to the pattern circuit, dried, and then heated to form an interlayer insulating film. Next, a conductive layer is formed on the interlayer insulating film by vapor deposition or the like, and etching is performed to form a pattern circuit.

In the manufacture of the printed circuit board, a solder resist layer may be laminated on the pattern circuit. The solder resist layer can be formed by the liquid composition described above, for example. Specifically, the liquid composition of the present invention may be applied to a pattern circuit, dried, and then heated to form a solder resist layer.

In addition, in the production of the printed circuit board, a cover film may be laminated. The cover film is typically composed of a base film and an adhesive layer formed on the surface thereof, and one surface of the adhesive layer is bonded to the printed board. As the base film of the cover film, for example, the above-described film can be used.

Further, an interlayer insulating film using the above-described film may be formed on a pattern circuit formed by etching a conductive layer of a metal laminated plate, and a polyimide film may be laminated as a cap film.

The printed circuit board obtained by the above-described manufacturing method of the present invention is useful for applications such as electronic device boards for radars, internet routers, back boards, wireless infrastructures, and the like, various sensor boards for automobiles, and engine management sensor boards, which require high-frequency characteristics, and is particularly suitable for applications aimed at reducing transmission loss in the millimeter wave band.

Examples

The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following descriptions. Examples 1 to 4, 8 and 9 are examples, and examples 5 to 7 and 10 are comparative examples.

[ measurement method ]

Various methods for measuring the fluorocopolymer and the resin powder are shown below.

(1) Copolymerization composition

The content ratio (% by mole) of the NAH-based unit in the copolymerization composition of the fluorocopolymer can be determined by the following infrared absorption spectrum analysis. The content ratio of the other units was determined by melt NMR analysis and fluorine content analysis.

< content ratio (mol%) of NAH-based units >

The fluorocopolymer was press-molded to obtain a film having a thickness of 200 μm, and the film was subjected to infrared spectroscopyThe infrared absorption spectrum is obtained by analysis. In the infrared absorption spectrum, the absorption peak in the NAH-based unit in the fluorocopolymer appeared at 1778cm^-1. The absorbance of the absorption peak was measured by using a molar absorption coefficient of NAH of 20810 mol^-1·l·cm^-1The content ratio of the NAH-based unit in the fluorocopolymer was determined.

(2) Melting Point (. degree.C.)

A melting peak of the fluorocopolymer at a temperature rise of 10 ℃ per minute was recorded by a differential scanning calorimeter (DSC device, manufactured by Seiko electronic Co., Ltd.), and the temperature (. degree.C.) corresponding to the maximum value was defined as the melting point (Tm).

(3) MFR (g/10 min)

The mass (g) of the fluorocopolymer which flowed out of a nozzle having a diameter of 2mm and a length of 8mm at 372 ℃ under a 49N load for 10 minutes (unit time) was measured by a melt index meter (manufactured by Techno 7 Co., Ltd. (テクノセブン)), and this value was defined as MFR.

(4) Relative dielectric constant

The relative dielectric constant was determined as a value measured at a frequency of 2.5GHz in an environment of 23 ℃ 2 ℃ and 50. + -. 5% RH by the SPDR (split dielectric resonator) method.

(5) Average particle diameter of fluorine-containing copolymer

The sieve was overlapped with a sieve of 2.000 mesh (pore size: 2.400mm), a sieve of 1.410 mesh (pore size: 1.705mm), a sieve of 1.000 mesh (pore size: 1.205mm), a sieve of 0.710 mesh (pore size: 0.855mm), a sieve of 0.500 mesh (pore size: 0.605mm), a sieve of 0.250 mesh (pore size: 0.375mm), a sieve of 0.149 mesh (pore size: 0.100mm), and trays in this order from top to bottom. A sample (fluorocopolymer) was put thereon and sieved with a shaker for 30 minutes. Thereafter, the mass of the sample remaining on each sieve was measured, and the cumulative total of the passing masses for each pore size value was graphically represented, and the particle size at which the cumulative total of the passing masses reached 50% was defined as the average particle size of the sample.

(6) Measurement of particle diameter Peak value, average particle diameter (D50) and D90 of resin powder

The resin powder was dispersed in water using a laser diffraction/scattering particle size distribution measuring device (horiba, horiba corporation, LA-920 measuring device), and the particle size distribution was measured to calculate the particle size peak value, the average particle size (D50), and D90.

(7) Bulk density of loose fill and bulk density of dense fill

The bulk density of the resin powder was measured by the methods described in International publication Nos. 2016/017801 [0117] and [0118 ].

(8) Peel strength

Test pieces having a length of 100mm and a width of 10mm were cut out from the metal laminate sheets obtained in each example. The adhesive layer and the insulating layer were peeled from one end of the test piece in the longitudinal direction to a position of 50 mm. Then, a position 50mm from one end of the test piece in the longitudinal direction was set as the center, and 90-degree peeling was performed at a tensile rate of 50 mm/min using a tensile tester (made by orlistat corporation, オリエンテック), and the maximum load was set as the peel strength (N/10 mm). The higher the peel strength, the more excellent the adhesion between the insulating layer and the adhesive layer.

(9) Particle size of particles and aggregates in insulator layer

The diameters of 100 powder particles were measured in multiples of 5000 by using a scanning electron microscope (model name: S-4800, Hitachi height technology, Ltd. (Hitachi ハイテクノロジーズ, Ltd.)) and the diameters were defined as particle diameters. The diameter of the particles is measured as the long side. In the case of powder aggregation, the aggregate is measured as one particle in diameter.

(10) A method for measuring the volume of particles and aggregates in the insulating layer.

The volume of the particles and aggregates in the insulating layer was determined as follows. That is, the average particle size of 100 particles and aggregates obtained by the above method, the total number of particles having a particle size of 10 μm or more present in a randomly selected 300 μm square range, and the average particle size of particles having a particle size of 10 μm or more are obtained, and the area ratio of the particles present in the insulating layer is obtained. The area ratio was determined as a volume ratio. The areas of the particles and the aggregates are assumed to be perfect circles, and the areas are calculated from the diameters and the numbers.

Production example 1

As monomers for forming the unit (1), NAH (nadic anhydride, manufactured by Hitachi chemical Co., Ltd.) and PPVE (CF) were used₂＝CFO(CF₂)₃F, Asahi glass company (manufactured by Asahi glass Co., Ltd.) was used together with [0123 ] of International publication No. 2016/017801]The above-mentioned process produces a copolymer (X-1).

The copolymerization composition of the copolymer (X-1) was 0.1/97.9/2.0 (mol%) of NAH units/TFE units/PPVE units. The copolymer (X1-1) had a melting point of 300 ℃, a relative dielectric constant of 2.1, an MFR of 17.6g/10 min and an average particle diameter of 1554 μm.

Next, the copolymer (X-1) was pulverized with a jet mill (model FS-4, model セイシン, Inc.) under a pulverizing pressure of 0.5MPa and a processing speed of 1kg/hr to give a resin powder, and then the resin powder was classified with a high-efficiency precision air classifier under a processing amount of 0.8kg/hr to give a powder (a-1).

The peak particle size of the powder (a-1) was 17 μm, the average particle size was 12 μm, and D90 was 19 μm. The loose bulk density of the powder (a-1) was 0.280g/mL, and the dense bulk density was 0.323 g/mL. The powder (a-1) does not include particles having a particle diameter exceeding 36 μm.

Production example 2

Powder (a-1) was classified by using the same high-efficiency precision air classifier as in production example 1 at a throughput of 0.5kg/hr to obtain powder (b-1).

The peak particle size of the powder (b-1) was 2.2. mu.m, the average particle size was 2.1. mu.m, and D90 was 7.1. mu.m. The loose bulk density of powder (b-1) was 0.278g/mL and the dense bulk density was 0.328 g/mL.

Production example 3

Powder (a-1) was classified by using the same high-efficiency precision air classifier as in production example 1 at a throughput of 0.5kg/hr to obtain powder (b-2).

The peak particle size of the powder (b-2) was 1.8. mu.m, the average particle size was 1.7 μm, and D90 was 6.5. mu.m. The loose bulk density of the powder (b-2) was 0.270g/mL, and the dense bulk density was 0.321 g/mL.

Production example 4

Resin powder (L150J, manufactured by Asahi glass Co., Ltd.) composed of PTFE was classified with the same high-efficiency precision air classifier as in production example 1 at a throughput of 0.3kg/hr to obtain powder (b-3).

The peak particle size of the powder (b-3) was 1.8. mu.m, the average particle size was 1.6 μm, and D90 was 6.3. mu.m. The loose bulk density of the powder (b-3) was 0.271g/mL, and the dense bulk density was 0.318 g/mL.

Production example 5

The powder (a-1) was classified by using a high-efficiency precision air classifier (model CLASSIEL N-01, manufactured by QINGRE CORPORATION) at a throughput of 0.7kg/hr to obtain a powder (b-4).

The peak particle size of the powder (b-4) was 3.5. mu.m, the average particle size was 4.8 μm, and D90 was 9.7. mu.m. The loose bulk density of powder (b-4) was 0.284g/mL, and the dense bulk density was 0.333 g/mL. The proportion of particles (A) having a particle diameter of 10 μm or more based on the total volume of the powder (B-4) was 7% by volume, and the proportion of particles (B) having a particle diameter of less than 10 μm based on the total volume of the powder (B-4) was 93% by volume.

As the powder (a-2), a resin powder (L150J, Asahi glass Co., Ltd.) composed of PTFE was prepared. The peak particle size of the powder (a-2) was 12 μm, the average particle size was 12 μm, and D90 was 27 μm. The powder (a-2) does not include particles having a particle diameter exceeding 36 μm.

As the powder (b-5), a resin powder (L170 JE, Asahi glass Co., Ltd.) composed of PTFE was prepared. The peak particle size of the powder (b-5) was 0.3. mu.m, the average particle size was 0.3. mu.m, and D90 was 0.4. mu.m.

[ example 1]

A predetermined amount of the powder was put into a 1L container, and shaken manually for 10 minutes to mix the powder (a-1) and the powder (b-1). The proportion of particles (a) having a particle diameter of 10 μm or more to the total volume of the obtained resin powder (mixed powder) was 18 vol%, and the proportion of particles (B) having a particle diameter of less than 10 μm to the total volume of the obtained resin powder (mixed powder) was 82 vol%.

The above-mentioned mixed powder was added to a U-varnish (made by yuken corporation) as a resin liquid. So that the mass ratio of the solid content weight in the U-varnish to the mixed powder is 59: the addition amount was determined in the manner of 41. The mixture was stirred with a stirrer at 1000rpm for 1 hour. Vacuum defoaming was performed for 30 minutes to obtain a liquid composition. In the liquid composition, no aggregation of the resin powder was observed in appearance.

The liquid composition filtered through a filter was applied to the surface of an electrolytic copper foil (manufactured by Fuda Metal foil powder Co., Ltd., CF-T4X-SVR-12, thickness: 12 μm, surface roughness (Rz): 1.2 μm) so that the thickness of the dried coating film (insulating layer) became 24 μm. The resulting laminate was dried by heating at 170 ℃ for 5 minutes, 190 ℃ for 3 minutes, and 220 ℃ for 1 minute in an oven to form an insulating layer, thereby obtaining a single-sided copper-clad laminate. The copper foil is then removed by etching to obtain a powder-containing film.

To 780g of N, N-Dimethylformamide (DMF) cooled to 10 ℃ were added 115.6g of 2, 2-bis [4- (4-aminophenoxy) phenyl ] propane (BAPP), and 78.7g of 3,3 ', 4, 4' -biphenyltetracarboxylic dianhydride (BPDA) was slowly added. Then, 3.8g of vinyl bis (trimellitic acid monoester anhydride (TMEG)) was added thereto, and the mixture was uniformly stirred in an ice bath for 30 minutes to obtain a prepolymer.

After 25.2g of p-Phenylenediamine (PDA) was dissolved in the prepolymer solution, 46.4g of pyromellitic dianhydride (PMDA) was dissolved, 115.1g (PMDA: 0.038mol) of a 7.2 mass% DMF solution of PMDA prepared separately was carefully added dropwise, and the addition was stopped when the viscosity reached about 2500 poise. Stirring was then carried out for 1 hour to obtain a polyamic acid solution having a rotational viscosity of 2600 poise at 23 ℃.

The polyamic acid solution filtered through a filter was applied to the surface of an electrolytic copper foil (manufactured by Fuda Metal foil powder Co., Ltd., CF-T4X-SVR-12, thickness: 12 μm, surface roughness (Rz): 1.2 μm) so that the thickness of the dried coating film (adhesive layer) became 12 μm. The single-sided copper-clad laminate was obtained by heating the laminate in an oven at 150 ℃ for 5 minutes, 180 ℃ for 5 minutes, and 250 ℃ for 5 minutes to form an adhesive layer and drying the adhesive layer.

The single-sided copper-clad laminate was laminated on both sides of the film containing the powder so that copper foils (conductive layers) were on the outer sides, and was imidized by vacuum heat-pressing at a pressing temperature of 350 ℃, a pressing pressure of 4.0MPa, and a pressing time of 15 minutes, to obtain a double-sided copper-clad laminate composed of copper/thermoplastic polyimide layer (adhesive layer)/non-thermoplastic polyimide layer (insulating layer)/thermoplastic polyimide layer (adhesive layer)/copper.

[ examples 2 to 7]

A metal laminate was obtained in the same manner as in example 1, except that the resin powder used was changed as shown in table 1.

[ examples 8 and 9]

Except that the amount of the mixed powder added was changed so that the ratio of the weight of the solid components in the U-varnish to the mass of the mixed powder reached 85: 15, a metal laminate was obtained in the same manner as in example 1.

[ example 10]

Except for changing to adding the powder (a-2): powder (b-2) 75% by volume: 25% by volume of the mixed powder, and such that the mass ratio of the solid content in the U-varnish to the mixed powder is 38: a metal laminate was obtained in the same manner as in example 1 except for 62.

The conditions and evaluation results of the examples are shown in table 1.

[ Table 1]

As shown in Table 1, in examples 1 to 4 and 8 and 9 in which the resin powder including the particles (A) and not including the particles exceeding the total thickness of the insulating layer and the adhesive layer was used and the surface roughness of the adhesive layer side of the insulating layer was set to 0.5 to 3.0. mu.m, the peel strength between the insulating layer and the adhesive layer was high, and high adhesive strength was obtained between the insulating layer and the adhesive layer.

On the other hand, in examples 5 to 7, the peel strength between the insulating layer and the adhesive layer was lower than that in the examples, and the adhesive strength between the insulating layer and the adhesive layer was inferior.

In example 10 in which the surface roughness of the insulating layer was 4.2 μm exceeding 3.0. mu.m, the adhesion strength between the copper foil and the adhesive layer was as low as 3N/cm when the peel strength between the adhesive layer and the insulating layer was measured, and the peel strength between the insulating layer and the adhesive layer could not be measured because the peel interface was between the adhesive layer and the copper foil. Since the copper-clad laminate has a weak peel strength, it is not suitable as a copper-clad laminate for printed board applications.

In examples 5 to 7 and 10 in which the content of the particles (A) and aggregates having a particle diameter of 10 μm or more contained in the insulating layer is not in the range of 5 to 18 vol%, the peel strength was low as described above, and the copper-clad laminate was not suitable.

In addition, the entire contents of the specification, claims, drawings and abstract of Japanese patent application 2016-170803 filed on 9/1 2016 are incorporated herein as disclosure of the present specification.

Description of the symbols

1,2: metal laminate 10, 20: insulating layer 12: adhesive layer 14: conductive layers 16, 30: resin powder 16a, 30 a: particles (a)16 b, 30 b: particle (B) 22: first adhesive layer 24: first conductive layer 26: second adhesive layer 28: second conductive layer

Claims (19)

1. A metal laminate comprising an insulating layer, an adhesive layer provided on at least one surface of the insulating layer in a thickness direction thereof, and a conductive layer provided on a surface of the adhesive layer opposite to the insulating layer,

the insulating layer contains a resin powder containing a fluororesin,

the resin powder includes particles having a particle diameter of 10 [ mu ] m or more, excluding particles having a particle diameter exceeding the total thickness of the insulating layer and the adhesive layer,

the content of the particles having a particle diameter of 10 μm or more in the insulating layer is 5 to 18 vol%,

the surface roughness of the surface of the insulating layer, which is provided with the bonding layer, is 0.5-3.0 mu m.

2. The metal laminate according to claim 1, wherein the resin powder further comprises particles having a particle size of less than 10 μm, and the content of the particles having a particle size of 10 μm or more is 8 to 63% by volume and the content of the particles having a particle size of less than 10 μm is 37 to 92% by volume, based on 100% by volume of the total of the particles having a particle size of 10 μm or more and the particles having a particle size of less than 10 μm.

3. The metal laminate according to claim 1, wherein the fluororesin is a fluorine-containing copolymer having a unit containing at least 1 functional group selected from a carbonyl group-containing group, a hydroxyl group, an epoxy group and an isocyanate group, and a tetrafluoroethylene-based unit and having a melting point of 260 to 320 ℃.

4. The metal laminate sheet of claim 3, wherein the fluorine-containing copolymer has a unit including the functional group, a tetrafluoroethylene-based unit, and a perfluoro (alkyl vinyl ether) -based unit,

each unit has the following ratio relative to the sum of all units;

a unit comprising said functional group: 0.01 to 3 mol%;

tetrafluoroethylene-based unit: 90-99.89 mol%;

perfluoro (alkyl vinyl ether) -based units: 0.1 to 9.99 mol%.

5. The metal laminate sheet according to claim 3, wherein the fluorine-containing copolymer has a unit including the functional group, a tetrafluoroethylene-based unit, and a hexafluoropropylene-based unit,

each unit has the following ratio relative to the sum of all units;

a unit comprising said functional group: 0.01 to 3 mol%;

tetrafluoroethylene-based unit: 90-99.89 mol%;

units based on said hexafluoropropene: 0.1 to 9.99 mol%.

6. The metal-laminated plate of claim 3, wherein the functional group is a carbonyl-containing group,

the carbonyl group-containing group is at least 1 selected from the group consisting of a group having a carbonyl group between carbon atoms of the hydrocarbon group, a carbonate group, a carboxyl group, an acid halide group, an alkoxycarbonyl group, and an acid anhydride residue.

7. The metal laminate as claimed in claim 1, wherein the insulating layer and the adhesive layer each have a relative dielectric constant of 2.1 to 3.5.

8. The metallic laminate of claim 1, wherein the insulating layer further comprises polyimide.

9. A method for producing a metal laminated plate according to any one of claims 1 to 8,

wherein the insulating layer is formed using resin powder,

laminating a conductive layer on at least one surface of the insulating layer in a thickness direction thereof via an adhesive layer;

the resin powder contains a fluororesin, and includes particles having a particle diameter of 10 [ mu ] m or more, and does not include particles having a particle diameter exceeding the total thickness of the insulating layer and the adhesive layer,

the content of the particles having a particle diameter of 10 μm or more in the insulating layer is 5 to 18 vol%.

10. The method for producing a metal laminated plate according to claim 9, wherein a resin powder obtained by mixing a powder (a) having a particle size peak of 10 to 100 μm and a powder (b) having a particle size peak of 0.3 to 8 μm is used.

11. The method of manufacturing a metal laminated plate according to claim 9 or 10, wherein at least one of the powder (a) and the powder (b) is

A fluorine-containing copolymer having a melting point of 260 to 320 ℃ and comprising a unit containing at least 1 functional group selected from a carbonyl group-containing group, a hydroxyl group, an epoxy group and an isocyanate group, and a tetrafluoroethylene-based unit.

12. The method of manufacturing a metal laminated plate according to claim 9, wherein the insulating layer is formed using a dispersion liquid in which the resin powder is dispersed in a liquid medium.

13. A method for manufacturing a printed board, comprising etching the conductive layer of the metal laminated plate according to any one of claims 1 to 8 to form a pattern circuit, thereby obtaining a printed board.

14. An insulating layer comprising a resin powder containing a fluororesin, wherein the resin powder in the insulating layer comprises at least one of particles having a particle diameter of 10 [ mu ] m or more and aggregates having a particle diameter of 10 [ mu ] m or more, and the content of the particles and aggregates is 5 to 18 vol% based on the total volume of materials forming the insulating layer.

15. The insulating layer according to claim 14, wherein the resin powder further comprises particles having a particle diameter of less than 10 μm, and the content of the particles having a particle diameter of 10 μm or more and the aggregates having a particle diameter of 10 μm or more is 8 to 63% by volume, and the content of the particles having a particle diameter of less than 10 μm is 37 to 92% by volume, based on 100% by volume of the total volume of the particles having a particle diameter of 10 μm or more and the aggregates having a particle diameter of 10 μm or more and the particles having a particle diameter of less than 10 μm.

16. The insulation layer according to claim 14 or 15, wherein the fluororesin is a fluorine-containing copolymer having a unit containing at least 1 functional group selected from a carbonyl group-containing group, a hydroxyl group, an epoxy group, and an isocyanate group, and a tetrafluoroethylene-based unit, and having a melting point of 260 to 320 ℃.

17. The insulating layer according to claim 14, wherein the relative dielectric constant is 2.1 to 3.5.

18. A method for producing an insulating layer according to any one of claims 14 to 17,

the insulating layer is formed using a dispersion liquid in which a resin powder (alpha) having a particle diameter peak of 10 to 100 [ mu ] m and a resin powder (beta) having a particle diameter peak of 0.3 to 8 [ mu ] m are mixed and dispersed in a liquid medium.

19. A metal laminate plate comprising an insulating layer, an adhesive layer provided on at least one surface of the insulating layer in the thickness direction thereof, and a conductive layer provided on the surface of the adhesive layer opposite to the insulating layer,

the insulating layer according to any one of claims 14 to 17, excluding any one of particles having a particle diameter exceeding the total thickness of the insulating layer and the adhesive layer and aggregates having a particle diameter of 10 μm or more.

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