WO2020137879A1 - Powder liquid dispersion, layered product, and printed base board - Google Patents

Abstract

[Problem] To provide a powder liquid dispersion that has excellent dispersibility, has less powder fall-off when used to form a layer (coating film), and allows improvement of the smoothness and UV workability of a surface of the obtained layer (coating film); and a layered product and printed base board obtained by using the powder liquid dispersion. [Solution] The powder liquid dispersion according to the present invention contains: a powder of a tetrafluoroethylene polymer; a (meth)acrylate polymer; a polyimide precursor or a polyimide; and a polar organic solvent, wherein the contained amount of the tetrafluoroethylene polymer is 10-60 mass%, and the ratio by mass of the contained amount of the polyimide precursor or polyimide with respect to the contained amount of the tetrafluoroethylene polymer is 0.3 or less.

Description

Powder dispersion, laminate and printed circuit board

The present invention relates to a powder dispersion containing a tetrafluoroethylene-based polymer powder and a polyimide precursor or polyimide in a predetermined amount, a laminate having a layer formed from the dispersion, and a printed circuit board.

Tetrafluoroethylene-based polymers such as polytetrafluoroethylene (PTFE) have excellent physical properties such as chemical resistance, water/oil repellency, heat resistance, and electrical properties, and are suitable for use in powders, powder dispersions, films, etc. , And various uses of the physical properties are known.
In recent years, when preparing a metal-clad laminate that can be processed into a printed circuit board having excellent electrical characteristics and heat resistance, a dispersion liquid obtained by further mixing various materials with a powder dispersion liquid containing a powder of tetrafluoroethylene-based polymer. Is being considered. In Patent Document 1, a metal-clad laminate is produced using a powder dispersion liquid containing such powder and a polyimide precursor.

JP, 2017-078102, A

▽Tetrafluoroethylene-based polymers generally have low affinity with other various materials such as polyimide precursor or polyimide. For this reason, the above-mentioned powder dispersion is still insufficient in its state stability (dispersibility, viscosity, thixotropy, etc.). If the content of tetrafluoroethylene-based polymer in the powder dispersion is increased (relatively lower content of polyimide) in order to form a layer (coating film) with more excellent electrical properties, its state stability will decrease. However, the present inventors have found that there is a problem that the physical properties of the layer (coating film) deteriorate.

The inventors of the present invention have made extensive studies to solve such a problem in a powder dispersion liquid containing a tetrafluoroethylene-based polymer powder and a polyimide precursor or polyimide and having a high content of the former. As a result, they have found that the adjustment of the content and mass ratio of each polymer and the blending of the (meth)acrylate polymer is effective. Further, from the powder dispersion in this case, powder falling is suppressed at the time of forming the layer (coating film), a layer (coating film) having excellent surface smoothness and low water absorption is formed. It was found that the adhesiveness and UV processability are excellent.

That is, the present invention is an invention made on the basis of such findings, the object thereof is excellent in dispersibility, powder falling is less likely to occur at the time of forming a layer (coating film), and the smoothness of the surface of the obtained layer (coating film). Disclosed is a powder dispersion capable of improving the properties and UV processability, and a laminate and a printed circuit board obtained by using the powder dispersion.

The present invention has the following aspects.
<1> Tetrafluoroethylene-based polymer powder, (meth)acrylate-based polymer, polyimide precursor or polyimide, and polar organic solvent are contained, and the content of the tetrafluoroethylene-based polymer is 10 to 60% by mass. And a powder dispersion liquid in which the mass ratio of the content of the polyimide precursor or the polyimide to the content of the tetrafluoroethylene-based polymer is 0.3 or less.
<2> The powder dispersion according to <1> above, wherein the ratio is 0.005 or more and 0.1 or less.
<3> When a solution was prepared by dissolving the polyimide precursor or polyimide in N-methyl-2-pyrrolidone so that the concentration was 0.5 g/dL, the logarithmic viscosity at 30° C. of the solution was 0. The powder dispersion liquid according to the above <1> or <2>, which is 2 to 3 dL/g.
<4> Any of the above <1> to <3>, wherein the polyimide precursor or polyimide is an aromatic polyimide precursor or aromatic polyimide obtained by reacting an aromatic tetracarboxylic dianhydride and a diamine. Kano powder dispersion.
<5> Any one of the above <1> to <4>, wherein the mass ratio of the content of the (meth)acrylate polymer to the content of the tetrafluoroethylene polymer is 0.02 to 0.15. Powder dispersion.
<6> The powder dispersion liquid according to any one of the above <1> to <5>, wherein the (meth)acrylate-based polymer contains a unit based on a (meth)acrylate having a hydroxyl group or an oxyalkylene group.
<7> The powder dispersion liquid according to any one of <1> to <6>, wherein the (meth)acrylate-based polymer includes a unit based on (meth)acrylate having a fluoroalkyl group or a fluoroalkenyl group.
<8> The powder dispersion liquid according to any one of <1> to <7>, wherein the polar organic solvent is a cyclic ester, a cyclic ketone or a cyclic amide.
<9> The powder dispersion liquid according to any one of <1> to <8>, further containing an inorganic filler.
<10> Any one of the above items <1> to <9>, further containing an inorganic filler, wherein the mass ratio of the content of the inorganic filler to the content of the tetrafluoroethylene-based polymer is 0.3 or less. Powder dispersion.
<11> The tetrafluoroethylene-based polymer is a tetrafluoroethylene-based polymer containing units based on units based on perfluoro(alkyl vinyl ether), or polytetrafluoroethylene having a number average molecular weight of 200,000 or less, The powder dispersion liquid according to any one of 1> to <10>.
<12> The tetrafluoroethylene-based polymer has a polar functional group containing a unit based on perfluoro(alkyl vinyl ether), or a unit based on perfluoro(alkyl vinyl ether) based on all units. The powder dispersion liquid according to any one of the above items <1> to <11>, which is a tetrafluoroethylene-based polymer having 0 to 5.0 mol% and having no polar functional group.
<13> A laminate having a metal substrate layer and a polymer layer which is provided on the surface of the metal substrate layer and is formed from the powder dispersion liquid according to any one of the above <1> to <12>.
<14> A printed circuit board obtained by processing the metal substrate layer of the laminate of <13> above into a patterned circuit.

ADVANTAGE OF THE INVENTION According to this invention, the powder dispersion liquid which is excellent in dispersibility, and is hard to generate|occur|produce powder at the time of layer (coating film) formation, and the layered product and printed circuit board which have the layer (coating film) excellent in surface smoothness and UV processability Will be provided.

It is the microscope picture which image|photographed the cross section of the periphery of the through-hole in the double-sided copper clad laminated body obtained from the film A. It is the microscope picture which image|photographed the cross section of the periphery of the through-hole in the double-sided copper clad laminated body obtained from the film E.

The following terms have the following meanings.
“D50 of powder” is a particle size distribution of powder measured by a laser diffraction/scattering method, and a cumulative curve is calculated by setting the total volume of particles constituting the powder (hereinafter, also referred to as “powder particles”) as 100%. , The particle diameter at the point where the cumulative volume becomes 50% on the cumulative curve (volume-based cumulative 50% diameter).
"Powder D90" is the point where the particle size distribution of powder is measured by the laser diffraction/scattering method, the cumulative volume is calculated with the total volume of the powder particle group as 100%, and the cumulative volume becomes 90% on the cumulative curve. Is the particle size (volume-based cumulative 90% size).
That is, D50 and D90 of the powder are the volume-based cumulative 50% diameter and the volume-based cumulative 90% diameter of the powder particles, respectively.
The “melt viscosity of the polymer” is based on ASTM D 1238, and a sample of the polymer (2 g) which had been heated for 5 minutes at the measurement temperature in advance using a flow tester and a die of 2Φ-8L was loaded with 0.7 MPa. It is the value measured by holding at the measurement temperature at.
The “viscosity of the powder dispersion” is a value measured for the powder dispersion using a B-type viscometer at room temperature (25° C.) and a rotation speed of 30 rpm. The measurement is repeated 3 times, and the average value of the measured values of 3 times is taken.
“Thixo ratio of powder dispersion” is a value obtained by dividing viscosity η ₁ of powder dispersion measured at a rotation speed of 30 rpm by viscosity η ₂ of powder dispersion measured at a rotation speed of 60 rpm. (Η ₁ /η ₂ ).
The “unit” in a polymer may be an atomic group formed directly from a monomer by a polymerization reaction, and the polymer obtained by the polymerization reaction may be treated by a predetermined method to convert an atomic group in which a part of the structure is converted. May be Further, a unit based on the monomer A is also referred to as a monomer A unit.

The powder dispersion liquid (present dispersion liquid) of the present invention is also referred to as a powder containing a tetrafluoroethylene-based polymer (hereinafter also referred to as “F polymer”) and a (meth)acrylate-based polymer (hereinafter referred to as “A polymer”). ), a polyimide precursor or polyimide (hereinafter, also collectively referred to as “PI”), and a polar organic solvent. It can be said that the powder is dispersed in a polar organic solvent.
This dispersion has an F polymer content of 10 to 60% by mass, and the ratio of the PI content to the F polymer content by mass is 0.3 or less. That is, it can be said that the present dispersion liquid is a dispersion liquid containing the A polymer, which has a high content of the F polymer and a low content of the PI.

This dispersion has excellent state stability such as dispersibility, viscosity, and thixotropy, does not easily fall off when forming a layer (coating film), has excellent surface smoothness, adhesiveness, and UV processability, and has excellent water absorption. The reason for forming the low layer (coating film) is not always clear, but it is considered as follows.
The surface tension of the polar organic solvent is reduced because the A polymer is highly soluble or dispersible in the polar organic solvent. As a result, the dispersion medium in the present invention is in a state of being easily wetted with the F polymer, and it is considered that a high content of the F polymer powder was highly dispersed. Further, PI is a small amount component, has a high degree of freedom in the dispersion medium, and is considered to easily interact with each polymer. For this reason, the present dispersion has excellent state stability.

Such a powder dispersion is applied to the surface of a metal substrate and heated to form a polymer layer containing an F polymer (hereinafter, also referred to as “F layer”) on the surface of the metal substrate layer to obtain a laminate. .. At this time, it is considered that the PI uniformly present in the powder dispersion liquid functions as a binder and suppresses the powder from falling off (powder drop) due to the formation of the F layer, and as a result, the F layer having high surface smoothness is formed. It is thought that Further, since PI is uniformly present in the F layer as it is, it is considered that the F layer having excellent adhesiveness and UV processability and having a low water absorption rate was formed.
The effects as described above are remarkably exhibited in a preferred embodiment of the present invention described later.

The D50 of the powder in the present invention is preferably 0.05 to 6 μm, more preferably 0.05 to 3 μm. Within this range, the fluidity and dispersibility of the powder will be good, and the electrical properties (low dielectric constant, etc.) and heat resistance of the F layer will be most easily exhibited. The D90 of the powder is preferably 8 μm or less, more preferably 5 μm or less. Within this range, the fluidity and dispersibility of the powder will be good, and the electrical properties (low dielectric constant, etc.) and heat resistance of the F layer will be most easily exhibited.
The loosely packed bulk density of the powder is preferably 0.08 to 0.5 g/mL. The close packing bulk density of the powder is preferably 0.1 to 0.8 g/mL. When the loosely packed bulk density or the densely packed bulk density is within the above range, the powder is excellent in handleability.

The powder in the present invention may contain a resin other than the F polymer, and is preferably composed of the F polymer. The content of the F polymer in the powder is preferably 80% by mass or more, more preferably 100% by mass.
Examples of the resin include aromatic polyester, polyamideimide, thermoplastic polyimide, polyphenylene ether, and polyphenylene oxide.

The F polymer in the present invention is a polymer containing a unit (TFE unit) based on tetrafluoroethylene (TFE).
The F polymer is a homopolymer (PTFE) composed of TFE units, a copolymer (PFA) containing TFE units and units (PAVE units) based on perfluoro(alkyl vinyl ether) (PAVE), TFE units and hexafluoropropylene (HFP). Copolymers containing units based on (HFP units) (FEP) or copolymers containing units based on TFE and units based on fluoroalkylethylene (FAE) (FAE units) are preferred.

PTFE also includes a polymer containing an extremely small amount of a unit other than the TFE unit. The polymer containing an extremely small amount of other units preferably contains 99.5 mol% or more, and more preferably 99.9 mol% or more of TFE units based on all the units contained in the polymer.
The melt viscosity of the polymer at 380° C. is preferably 1×10 ² to 1×10 ⁸ Pa·s, more preferably 1×10 ³ to 1×10 ⁶ Pa·s.
Such polymers include low molecular weight PTFE.

Low-molecular-weight PTFE is obtained by irradiating high-molecular-weight PTFE (melt viscosity is about 1×10 ⁹ to 1×10 ¹⁰ Pa·s) with radiation (International Publication No. 2018/026012, International Publication No. 2018). No. /026017, etc.), and PTFE obtained by using a chain transfer agent in the production of PTFE by polymerizing TFE (JP 2009-1745 A, WO 2010/114033). And a polymer described in JP-A-2005-232082), which has a core-shell structure composed of a core portion and a shell portion, and in which only the shell portion has the above melt viscosity. (Polymers described in Japanese Patent Publication No. 2005-527652, International Publication No. 2016/170918, Japanese Patent Laid-Open No. 09-087334, etc.) may be used.

F polymers also include polymers containing other units than TFE units. The polymer containing other units preferably contains more than 0.5 mol% of other units with respect to the total units of the polymer. Such other units are preferably PAVE units, HFP units, FAE units or units having a functional group described later.
The F polymer preferably has at least one functional group selected from the group consisting of a carbonyl group-containing group, a hydroxy group, an epoxy group, an oxetanyl group, an amino group, a nitrile group and an isocyanate group. When the F polymer has the above functional group, the adhesiveness of the F layer is further improved. The carbonyl group-containing group includes an amide group.

The functional group may be contained in a unit forming the F polymer, may be contained in an end group of the polymer main chain, or may be introduced into the F polymer by plasma treatment or the like. Examples of the F polymer having the above functional group in the terminal group of the polymer main chain include F polymers having a functional group as the terminal group derived from a polymerization initiator, a chain transfer agent and the like.
The functional group is preferably a hydroxy group or a carbonyl group-containing group, more preferably a carbonyl-containing group, more preferably a carbonate group, a carboxy group, a haloformyl group, an alkoxycarbonyl group or an acid anhydride residue, and a carboxy group or an acid anhydride. Residues are more preferred.
The F polymer is preferably a polymer containing TFE units, PAVE units, HFP units or FAE units, and units having a functional group.

The unit having a functional group is preferably a unit based on a monomer having a functional group.
As the monomer having a functional group, a monomer having a hydroxy group or a carbonyl group-containing group is preferable, a monomer having an acid anhydride residue or a carboxy group is more preferable, and a cyclic monomer having an acid anhydride residue is further preferable.
Examples of the cyclic monomer include itaconic anhydride, citraconic anhydride, 5-norbornene-2,3-dicarboxylic anhydride (also known as hymic anhydride; hereinafter also referred to as “NAH”) or maleic anhydride. Is preferred.

As PAVE, CF ₂ ═CFOCF ₃ , CF ₂ ═CFOCF ₂ CF ₃ , CF ₂ ═CFOCF ₂ CF ₂ CF ₃ (PPVE), CF ₂ ═CFOCF ₂ CF ₂ CF ₂ CF ₃ , CF ₂ ═CFO(CF ₂ ) ₈ F is mentioned, PPVE is preferable.
As FAE, CH ₂ ═CH(CF ₂ ) ₂ F, CH ₂ ═CH(CF ₂ ) ₃ F, CH ₂ ═CH(CF ₂ ) ₄ F, CH ₂ ═CF(CF ₂ ) ₃ H, CH ₂ ═CF(CF ₂ ) ₄ H, CH ₂ ═CH(CF ₂ ) ₄ F or CH ₂ ═CH(CF ₂ ) ₂ F is preferred.
In this case, the TFE unit is preferably contained in an amount of 90 to 99 mol %, and the PAVE unit, the HFP unit or the FAE unit is contained in an amount of 0.5 to 9.97 mol% based on all units contained in the F polymer. Preferably, the unit having a functional group is contained in an amount of 0.01 to 3 mol %.
In this case, the melting temperature of the F polymer is preferably 250 to 380°C, more preferably 280 to 350°C.
Specific examples of the F polymer include the polymers described in WO2018/16644.

Suitable examples of the F polymer include a tetrafluoroethylene-based polymer containing a unit based on perfluoro(alkyl vinyl ether), or PTFE having a number average molecular weight of 200,000 or less.
The number average molecular weight of PTFE is a value calculated based on the following formula (1).
Mn=2.1×10 ¹⁰ ×ΔHc ^−5.16 (1)
In the formula (1), Mn represents the number average molecular weight of the PTFE, and ΔHc represents the crystallization calorie (cal/g) of the PTFE measured by the differential scanning calorimetry.
The Mn of PTFE is preferably 10 or less, more preferably 50,000 or less. The Mn of PTFE is preferably 10,000 or more.

As a more preferable embodiment of the F polymer, a tetrafluoroethylene-based polymer having a functional group containing a unit based on perfluoro(alkyl vinyl ether) or a unit based on perfluoro(alkyl vinyl ether) is 2.0 to An example is a tetrafluoroethylene-based polymer containing 5.0 mol% and having no functional group.
In the F polymer of this embodiment, not only is the powder excellent in dispersion stability, but it is also easy for the F polymer to be densely and uniformly distributed in the F layer formed from the present dispersion liquid. In addition, fine spherulites are easily formed in the F layer, and the adhesiveness with other components is likely to increase. As a result, the F layer having the high physical properties of each of the three components is more likely to be formed.

The former polymer contains 90 to 99 mol% of TFE units, 0.5 to 9.97 mol% of PAVE units, and 0.01 to 3 mol% of units based on a monomer having a functional group, based on all units. It is preferable to contain each of them.
The content of PAVE units in the latter polymer is preferably 2.1 mol% or more, more preferably 2.2 mol% or more, based on all units.
The latter polymer is composed of only TFE units and PAVE units, and preferably contains 95.0 to 98.0 mol% of TFE units and 2.0 to 5.0 mol% of PAVE units based on all units. ..

The latter polymer does not have a functional group means that the polymer has less than 500 functional groups per 1×10 ⁶ carbon atoms constituting the polymer main chain. Means The number of the functional groups is preferably 100 or less, more preferably 50 or less. The lower limit of the number of functional groups is usually 0.
The latter polymer may be produced by using a polymerization initiator, a chain transfer agent, or the like that does not generate a functional group as a terminal group of the polymer chain, and has an F polymer having a functional group (a polar functional group derived from the polymerization initiator). F polymer having a group in the terminal group of the main chain of the polymer) may be fluorinated. Examples of the fluorination method include a method using fluorine gas (see JP-A-2019-194314).

The polar organic solvent in the present invention is a compound that is liquid at 25°C, and may be an aqueous solvent or a non-aqueous solvent.
The polar organic solvent is preferably an amide, an alcohol, a sulfoxide, an ester, a ketone or a glycol ether, more preferably an ester, a ketone or an amide, still more preferably a cyclic ester, a cyclic ketone or a cyclic amide. The A polymer in the present invention has a high interaction with these polar organic solvents, and thus the layer (coating film) formability (thixo ratio, adhesiveness, transparency, etc.) of the powder dispersion is easily improved. The polar organic solvent may be used alone or in combination of two or more.

Specific examples of the polar organic solvent include methanol, ethanol, isopropanol, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, diethyl ether, dioxane, ethyl lactate, ethyl acetate. , Butyl acetate, γ-butyrolactone, methyl ethyl ketone, methyl isopropyl ketone, cyclopentanone, cyclohexanone, ethylene glycol monoisopropyl ether, cellosolve (methyl cellosolve, ethyl cellosolve, etc.).
The polar organic solvent is preferably a compound having a boiling point of 80 to 275°C, more preferably a compound having a boiling point of 125 to 250°C. Within this range, when the polar organic solvent is distilled off from the powder dispersion by heating, the volatilization of the polar organic solvent and the decomposition and flow of the A polymer effectively proceed.
The polar organic solvent is preferably N-methyl-2-pyrrolidone, γ-butyrolactone, cyclohexanone or cyclopentanone, more preferably cyclohexanone or N-methyl-2-pyrrolidone.

The A polymer in the present invention is a polymer containing an acrylate or methacrylate unit. The A polymer is a polymer other than the F polymer.
The polymer A preferably contains a unit based on a (meth)acrylate having a hydroxyl group, an oxyalkylene group or a thermally decomposable group (hereinafter, also referred to as “unit H”), and has a hydroxyl group or an oxyalkylene group (meth). More preferably it comprises units based on acrylates.
Examples of such (meth)acrylate include compounds represented by the following formulas (1) to (3).
Formula (1): CH ₂ =CX ^H C(O)O-Q ¹ -R ¹
Formula (2): CH ₂ =CX ^H C(O)OC(-R ² ) ₃
Formula (3): CH ₂ =CX ^H C(O)OC(-R ³¹ )(-R ³² ) ₂
The symbols in the formulas have the following meanings.
X ^H is a hydrogen atom or a methyl group.
Q ¹ is a polyoxyalkylene group, preferably a polyoxyethylene group or a polyoxypropylene group, and more preferably a polyoxyethylene group.
R ¹ is a hydrogen atom, an alkyl group or an aryl group, preferably a hydrogen atom, a methyl group, a nonyl group, a lauryl group, a stearyl group, a phenyl group, a stearylphenyl group, a laurylphenyl group or a nonylphenyl group, and a hydrogen atom or A methyl group is more preferred.
R ² is a hydrogen atom, an alkyl group or an aryl group, and at least one of the three R ² is an aryl group. R ² is preferably an alkyl group having 1 to 6 carbon atoms or a phenyl group, more preferably a methyl group or a phenyl group.
R ³¹ is a hydrogen atom or an alkoxy group, preferably a hydrogen atom or an alkoxy group having 1 to 3 carbon atoms, and more preferably a hydrogen atom.
The two R ^{32 s} together form an alkylene group.

The A polymer containing units based on such (meth)acrylate not only promotes the dispersion of the F polymer in the powder dispersion and the interaction with PI, but also heats the powder dispersion to form a layer (coating film). Since it is easily decomposed when it is formed, it is particularly easy to improve the layer (coating film) formability of the powder dispersion liquid.

Specific examples of the above compound include CH ₂ ═C(CH ₃ )C(O)O—(CH ₂ CH ₂ O) ₁₀ —H, CH ₂ ═C(CH ₃ )C(O)O—(CH ₂ CH ₂ O) ₂₃ -H, CH ₂ =C(CH ₃ )C(O)O-(CH ₂ CH ₂ O) ₂₃ -CH ₃ , CH ₂ =C(CH ₃ )C(O)O-(CH ₂ CH ₂ O) ₆₆ —CH ₃ , CH ₂ ═C(CH ₃ )C(O)O—(CH ₂ CH ₂ O) ₉₀ —CH ₃ , CH ₂ ═C(CH ₃ )C(O)O— (CH ₂ CH ₂ O) ₁₂₀ -CH ₃ , CH ₂ =C(CH ₃ )C(O)O-(CH ₂ CH ₂ O) ₃₀ -(CH ₂ ) ₁₂ H, CH ₂ =C(CH ₃ ). C(O)O—(CH ₂ CH ₂ O) ₆ ·(CH ₂ CH(CH ₃ )O) ₅ —Ph, CH ₂ ═C(CH ₃ )C(O)OCH ₂ Ph, CH ₂ ═C( CH ₃ )C(O)OCH(CH ₃ )Ph, CH ₂ ═C(CH ₃ )C(O)OCH<Nb, CH ₂ ═CHC(O)O—(CH ₂ CH ₂ O) ₁₀ —H, CH ₂ ═CHC(O)O—(CH ₂ CH ₂ O) ₂₃ —H, CH ₂ ═CHC(O)O—(CH ₂ CH ₂ O) ₂₃ —CH ₃ , CH ₂ ═CHC(O)O— (CH ₂ CH ₂ O) ₆₆ —CH ₃ , CH ₂ ═CHC(O)O—(CH ₂ CH ₂ O) ₉₀ —CH ₃ , CH ₂ ═CHC(O)O—(CH ₂ CH ₂ O) ₁₂₀ —CH ₃ , CH ₂ ═CHC(O)O—(CH ₂ CH ₂ O) ₃₀ —(CH ₂ ) ₁₂ H, CH ₂ ═CHC(O)O—(CH ₂ CH ₂ O) ₆ ·(CH ₂ CH(CH ₃ )O) ₅ -Ph, CH ₂ ═CHC(O)OCH ₂ Ph, CH ₂ ═CHC(O)OCH(CH ₃ )Ph, CH ₂ ═CHC(O)OCH<Nb. In the above compounds, Ph represents a phenyl group and —CH<Nb represents an isobornyl group.

Further, the A polymer preferably contains a unit (hereinafter, also referred to as “unit F”) based on a (meth)acrylate having a fluoroalkyl group or a fluoroalkenyl group.
Examples of such (meth)acrylate include compounds represented by the following formula F.
Formula F: CH ₂ =CX ^F C(O)O-Q ^F- R ^F
The symbols in the formulas have the following meanings.
X ^F is a hydrogen atom, a chlorine atom or a methyl group.
Q ^F is a methylene group, an ethylene group, an oxyethylene group or an oxybutylene group. However, when R ^F is a polyfluoroalkyl group having 1 to 6 carbon atoms or a polyfluoroalkyl group having 3 to 6 carbon atoms containing an etheric oxygen atom, Q ^F is preferably a methylene group or an ethylene group. Further, when R ^F is a polyfluoroalkenyl group having 4 to 12 carbon atoms, Q ^F is preferably an oxyethylene group or an oxybutylene group.
R ^F is a polyfluoroalkyl group having 1 to 6 carbon atoms, a polyfluoroalkyl group having 3 to 6 carbon atoms containing an etheric oxygen atom, or a polyfluoroalkenyl group having 4 to 12 carbon atoms.
R ^F includes —(CF ₂ ) ₄ F, —(CF ₂ ) ₆ F, —CF ₂ OCF ₂ CF ₂ OCF ₂ CF ₃ , —CF(CF ₃ )OCF ₂ CF ₂ CF ₃ , —CF(CF _{3) C (= C (CF} 3) 2) (CF (CF 3) 2) or _{-C (CF 3) C (=} C (CF (CF 3) 2) 2) is preferable, - _{(CF 2) 4} More preferred is F, -(CF ₂ ) ₆ F, -CF ₂ OCF ₂ CF ₂ OCF ₂ CF ₃ or -CF(CF ₃ )OCF ₂ CF ₂ CF ₃ . Among them, the physical properties of the F layer (wettability, adhesiveness, smoothness, etc.) from the viewpoint of further excellent, ^{R F} is, - _{(CF 2) 4} F or - _{(CF 2) 6} F are more preferred, - (CF ₂ ) ₆ F is particularly preferred.

The A polymer containing units based on such (meth)acrylate promotes the dispersion of the F polymer in the powder dispersion liquid and the interaction with PI, and therefore it is particularly easy to improve the dispersibility of the powder dispersion liquid.

Specific examples of the above compound include CH ₂ ═C(CH ₃ )C(O)OCH ₂ CH ₂ (CF ₂ ) ₆ F, CH ₂ ═CHC(O)OCH ₂ CH ₂ (CF ₂ ) ₆ F, CH. _{2 = C (CH 3) C} (O) OCH 2 CH 2 (CF 2) 4 F, CH 2 = CClC (O) OCH 2 CH 2 (CF 2) 4 F, CH 2 = C (CH 3) C ( _{O) OCH 2 CH 2 CH 2} CH 2 OCF (CF 3) C (= C (CF 3) 2) (CF (CF 3) 2), CH 2 = C (CH 3) C (O) OCH 2 CH 2 _{CH 2 CH 2 OC (CF 3} ) C (= C (CF (CF 3) 2) 2) can be mentioned.

The amount of the unit H with respect to all units contained in the A polymer is preferably 5 to 60 mol%, more preferably 5 to 45 mol%, and further preferably 10 to 30 mol%.
The amount of the unit F with respect to all the units contained in the A polymer is preferably 40 to 95 mol%, more preferably 55 to 95 mol%, and further preferably 70 to 90 mol%.
When the amount of each unit with respect to all the units contained in the A polymer is within the above range, the dispersibility of the powder dispersion liquid is further improved, and various physical properties of the F layer are well-balanced.
The polymer A may be composed of only the unit H and the unit F, and may further include an additional unit other than the unit H and the unit F as long as the effects of the present invention are not impaired.

The fluorine content of the A polymer in the present invention is preferably 10 to 60% by mass, more preferably 20 to 50% by mass, and further preferably 25 to 45% by mass. When the lower limit of the fluorine content is within the above range, the dispersibility of the powder dispersion is excellent. If the upper limit of the fluorine content is in the above range, the affinity of the A polymer for each component of the powder dispersion will be balanced, so that the layer (coating film) formability will be improved in addition to the dispersibility of the powder dispersion. Cheap. For example, the F layer is characterized by high wettability and excellent surface smoothness and adhesiveness. The fluorine content of the A polymer can be calculated from the type of monomer used in its synthesis and the charged amount thereof.

PI in the present invention is a polyimide precursor or polyimide. The polyimide precursor is a compound that is imidized to form a polyimide when the F polymer (powder) is baked.
As the polyimide, an aromatic polyimide obtained by reacting a tetracarboxylic dianhydride and a diamine is preferable, and at least one of the tetracarboxylic dianhydride and the diamine is an aromatic polyimide having an aromatic ring (semi-aromatic polyimide or A wholly aromatic polyimide) is more preferable, and an aromatic polyimide obtained by reacting an aromatic tetracarboxylic dianhydride and a diamine is further preferable.
Since the aromatic polyimide has an absorptivity for ultraviolet rays having a wavelength of 355 nm which is generally used in a UV laser, the UV processability of the obtained F layer is further improved. Further, when the F layer is formed, aromatic rings having high planarity are likely to be laminated, so that the mechanical strength and heat resistance of the F layer are also improved.

Examples of aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 3,3′4,4′-biphenyltetracarboxylic dianhydride, and 2,2′,3,3′-biphenyltetracarboxylic dianhydride. Anhydride, 2,3,3',4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-biphenylethertetracarboxylic dianhydride, 3,3',4,4'- Diphenylsulfone tetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 1,1 -Bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, Bis(3,4-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)sulfone dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, bis(3,3 4-dicarboxyphenyl)ether dianhydride, benzene-1,2,3,4-tetracarboxylic dianhydride, 3,3′,4,4′-benzophenone tetracarboxylic dianhydride, 2,3,3 2',3'-benzophenone tetracarboxylic dianhydride, 2,3,3',4'-benzophenone tetracarboxylic dianhydride, 1,2,5,6-naphthalene tetracarboxylic dianhydride, 2, 3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,4,5-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,6- Dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,7-Dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7- Tetrachlornaphthalene-1,4,5,8-tetracarboxylic dianhydride, phenanthrene-1,8,9,10-tetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)dimethylsilane dianhydride Substance, bis(3,4-dicarboxyphenyl)methylphenylsilane dianhydride, bis(3,4-dicarboxyphenyl)diphenylsilane dianhydride, 1,4-bis(3,4-dicarboxyphenyldimethylsilyl) ) Benzene dianhydride, 1,3-bis(3,4-dicarboxyphenyl)-1,1,3,3-tetramethyldicyclohexane dianhydride, p-phenylene bis(trimellitic acid monoester) Acid anhydride), 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]hexafluoropropane dianhydride And 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride and 4,4-bis(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride.

Examples of the aliphatic tetracarboxylic dianhydride include ethylene tetracarboxylic dianhydride, butane tetracarboxylic dianhydride, meso-butane-1,2,3,4-tetracarboxylic dianhydride, 3,3′ ,4,4'-biscyclohexanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1, 2,4,5-Cyclohexanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, bicyclo[2.2.2]oct -7-ene-2,3,5,6-tetracarboxylic dianhydride, 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2 -Dicarboxylic acid anhydride and 1,1'-bicyclohexane-3,3',4,4'-tetracarboxylic acid dianhydride.

Examples of aromatic diamines include o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 3,3′-diaminodiphenyl ether, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 3,3′- Diaminodiphenylmethane, 3,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, 3,3′-diaminodiphenyldifluoromethane, 4,4′-diaminodiphenyldifluoromethane, 3,3′-diaminodiphenylsulfone, 3, 4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl Ketone, 3,4'-diaminodiphenyl ketone, 4,4'-diaminodiphenyl ketone, 2,2-bis(3-aminophenyl)propane, 2,2-(3,4'-diaminodiphenyl)propane, 2, 2-bis(4-aminophenyl)propane, 2,2-bis(3-aminophenyl)hexafluoropropane, 2,2-(3,4′-diaminodiphenyl)hexafluoropropane, 2,2-bis(4 -Aminophenyl)hexafluoropropane, 1,3-bis(3-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 3,3'-[1,4-phenylenebis(1-methyl) Ethylidene)]bisaniline, 3,4′-[1,4-phenylenebis(1-methylethylidene)]bisaniline, 4,4′-[1,4-phenylenebis(1-methylethylidene)]bisaniline, 2,2 -Bis[4-(3-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]hexa Fluoropropane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, bis[4-(3-aminophenoxy)phenyl]sulfide, bis[4-(4-aminophenoxy)phenyl]sulfide , Bis[4-(3-aminophenoxy)phenyl] sulfone, bis[4-(4-aminophenoxy)phenyl] sulfone, 1,3-bis(4-aminophenoxy)propane, 1,4-bis(4- Aminophenoxy)butane, 1,5-bis(4-aminophen) Noxyl) heptane.

As the aliphatic diamine, 1,2-ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,6-hexamethylenediamine, 1,5-diaminopentane, 1, 10-diaminodecane, 1,2-diamino-2-methylpropane, 2,3-diamino-2,3-butanediamine, 2-methyl-1,5-diaminopentane, 1,3-bis(aminomethyl)cyclohexane , 1,4-bis(aminomethyl)cyclohexane, 1,4-diaminocyclohexane, 4,4′-methylenebis(cyclohexylamine) and 4,4′-methylenebis(2-methylcyclohexylamine).

The aromatic polyimide is preferably a semi-aromatic or wholly aromatic polyimide obtained by reacting an aromatic tetracarboxylic dianhydride with an aromatic diamine and/or an aliphatic diamine, and an aromatic tetracarboxylic dianhydride. A wholly aromatic polyimide obtained by reacting with an aromatic diamine is more preferable.
Examples of the aromatic tetracarboxylic dianhydride include 3,3′,4,4′-biphenyltetracarboxylic dianhydride, 3,3′,4,4′-benzophenone tetracarboxylic dianhydride, and 3,3′. At least one selected from the group consisting of',4,4'-biphenyl ether tetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride and pyromellitic dianhydride Is preferred. On the other hand, the aromatic diamine is selected from the group consisting of o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 3,3′-diaminodiphenyl ether, 4,4′-diaminodiphenyl ether, and 3,4′-diaminodiphenyl ether. At least one selected is preferable.
If the PI contains at least these monomers, the UV processability of the F layer can be further improved, and the F layer can be provided with excellent heat resistance and low water absorption required when it is used as a printed board. ..

Further, the logarithmic viscosity (ηihn) of PI in the present invention is preferably 0.2 to 3 dL/g, more preferably 0.5 to 2 dL/g. The logarithmic viscosity is a value represented by the following formula.
Formula: ηihn=[ln(η/η0)]/C
In the formula, η is a solution prepared by dissolving PI in N-methyl-2-pyrrolidone (NMP) so that the concentration becomes 0.5 g/dL, and the solution is prepared at about 30° C. (30±0.01 C) is the value measured with an Ubbelohde viscometer, η0 is the value measured with the same viscosity of the same solvent at the same temperature, and C is the concentration of 0.5 g/dL.
Here, the logarithmic viscosity (intrinsic viscosity) of PI correlates with the molecular weight of PI.
If the logarithmic viscosity of PI is within the above range, the molecular weight and viscosity of PI will be appropriate, and the effect of suppressing the sedimentation of PI powder will be suitably exerted, and the dispersibility of the powder in the powder dispersion liquid will be good. , PI suitably functions as a binder, and the effect of preventing powder falling during formation of the F layer is further improved.

The ratio (content) of the powder (F polymer) in the present dispersion liquid is 10% by mass or more, more preferably 25% by mass or more, and further preferably 30% by mass or more. The above ratio is 60% by mass or less, and more preferably 50% by mass or less. Within this range, it is easy to form an F layer having excellent surface smoothness, electrical characteristics and heat resistance.
The proportion (content) of the polar organic solvent in this dispersion is preferably 30 to 70% by mass, more preferably 40 to 60% by mass. Within this range, the coatability of the powder dispersion is excellent and the layer formability is likely to be improved.
In the present dispersion, the mass ratio of the content of the A polymer to the content of the powder (F polymer) is preferably 0.02 to 0.15, more preferably 0.05 to 0.12. Within this range, the dispersibility of the powder dispersion is further improved, and the physical properties (electrical properties, adhesiveness, surface smoothness, etc.) of the F layer are more easily improved.

In this dispersion, the mass ratio of the content of PI to the content of the powder (F polymer) is 0.3 or less, preferably 0.1 or less, more preferably less than 0.1, and 0.1. 09 or less is more preferable, and 0.05 or less is particularly preferable.
The mass ratio is preferably 0.005 or more, more preferably 0.01 or more.
The range of the mass ratio is preferably 0.005 or more and less than 0.1, more preferably 0.01 to 0.09, and further preferably 0.01 to 0.05. In this range, the sedimentation of the powder is suppressed, so that the dispersibility of the powder dispersion liquid is further improved, and further, the powder falling prevention effect in the F layer and the UV processability imparting effect in the F layer are more easily improved.
Particularly, in the present invention, the content and mass ratio of the powder (F polymer), A polymer and PI are set within the above ranges, so that the generation of powder falling during the formation of the F layer can be effectively suppressed and the F layer can be effectively prevented. In, various physical properties (smoothness, electrical characteristics, heat resistance, low water absorption) are exhibited in a good balance.

The present dispersion liquid may contain other materials as long as the effects of the present invention are not impaired. Other materials may or may not dissolve in the powder dispersion.
Examples of such other materials include non-curable resins and inorganic fillers.
Examples of the non-curable resin include non-melting resins such as cured products of curable resins, thermoplastic resins, and heat-melting resins such as heat-melting cured products of curable resins.
As the thermoplastic resin, polyester resin, polyolefin resin, styrene resin, polycarbonate, polyarylate, polysulfone, polyallylsulfone, aromatic polyamide, aromatic polyetheramide, polyphenylene sulfide, polyallyl ether ketone, polyamideimide, liquid crystallinity Examples thereof include polyester and polyphenylene ether, and thermoplastic polyimide, liquid crystalline polyester, liquid crystalline polyesteramide or polyphenylene ether is preferable.

Examples of the inorganic filler include a nitride filler and an inorganic oxide filler, and a boron nitride filler, beryllia (an oxide of beryllium), a silica filler or a metal oxide (cerium oxide, alumina, soda alumina, magnesium oxide, zinc oxide). , Titanium oxide, etc.) filler is preferred.
The present dispersion contains a (meth)acrylate polymer and a polyimide precursor or polyimide, which can be said to be a polar polymer, and has excellent liquid physical properties (viscosity, thixo ratio, etc.) and excellent dispersibility even if it contains an inorganic filler. .. Further, when the F layer is formed from it, not only is the inorganic filler less likely to fall off, but an F layer in which it is evenly distributed is likely to be formed.

The shape of the inorganic filler may be granular, non-granular (scaly, layered), or fibrous, and it is preferable to use an inorganic filler having a fine structure.
Specific examples of the inorganic filler having such a fine structure include spherical inorganic fillers and fibrous inorganic fillers.
The average particle size of the former inorganic filler is preferably 0.001 to 3 μm, more preferably 0.01 to 1 μm. In this case, the inorganic filler is more excellent in dispersibility in the powder dispersion liquid, and is more likely to be uniformly distributed in the F layer.
In the latter inorganic filler, the length is the fiber length and the diameter is the fiber diameter. The fiber length is preferably 1 to 10 μm. The fiber diameter is preferably 0.01 to 1 μm.
When the present dispersion liquid contains an inorganic filler, its content is preferably 0.1 or less in terms of mass ratio to the content of the F polymer.

At least a part of the surface of the inorganic filler may be coated (surface treated) with an organic material, an inorganic material (however, it is an inorganic material different from the inorganic material forming the inorganic filler), or both. ..
Organic substances used for such coating treatment include polyhydric alcohols (trimethylolethane, pentaerythritol, propylene glycol, etc.), saturated fatty acids (stearic acid, lauric acid, etc.), their esters, alkaneamines, amines (trimethylamine, triethylamine). Etc.), paraffin wax, silane coupling agent, silicone, and polysiloxane.
Examples of the inorganic substance used for such coating treatment include oxides, hydroxides, hydrated oxides or phosphates of aluminum, silicon, zirconium, tin, titanium, antimony and the like.

The inorganic filler to be contained in this dispersion may be determined according to the physical properties imparted to the F layer to be formed.
For example, in the case of forming the F layer in which the warp is highly suppressed while further improving the UV processability, the present dispersion liquid preferably contains a spherical silica filler as the inorganic filler.
In this case, the average particle diameter of the spherical silica filler is preferably smaller than the average particle diameter (D50) of the F polymer powder. Specifically, it is preferable that the F polymer powder has an average particle size of 0.2 to 3 μm, and the spherical silica filler has an average particle size of 0.01 to 0.1 μm. In addition, the content of the spherical silica filler in this case is preferably 0.01 to 0.1 in terms of mass ratio to the mass content of the F polymer. With such a configuration, it is possible to easily form the F layer in which the silica filler is uniformly dispersed in the F layer while suppressing the exposure of the silica filler on the surface of the F layer.

Preferable specific examples of such inorganic fillers include silica fillers having an average particle diameter of 1 μm or less which are surface-treated with an aminosilane coupling agent (manufactured by Admatechs Co., Ltd., “Admafine” series, etc.), and esters such as propylene glycol dicaprate. Surface-treated zinc oxide having an average particle diameter of 0.1 μm or less (Sakai Chemical Industry Co., Ltd., “FINEX” series, etc.), spherical fused silica having an average particle diameter of 0.5 μm or less and a maximum particle diameter of less than 1 μm (manufactured by DENKA CORPORATION) , "SFP grade", etc.), rutile type titanium oxide with an average particle size of 0.5 μm or less coated with a polyhydric alcohol and an inorganic substance (Ishihara Sangyo Co., Ltd., "Taipeque" series, etc.), and surface-treated with alkylsilane. Examples thereof include rutile type titanium oxide having an average particle size of 0.1 μm or less (“JMT” series manufactured by Teika Co., Ltd.).

When the present dispersion contains an inorganic filler, the ratio by mass of the content of the inorganic filler to the content of the powder (F polymer) in the present dispersion is preferably 0.3 or less, and more preferably 0.1 or less. preferable.
The above ratio is preferably 0.01 or more.
The range of the above ratio is preferably 0.01 to 0.3, more preferably 0.01 to 0.1. Within this range, the physical properties of the individual inorganic fillers are likely to be highly exhibited in the F layer.

In the present invention, such other materials include thixotropic agents, antifoaming agents, reactive alkoxysilanes, dehydrating agents, plasticizers, weathering agents, antioxidants, heat stabilizers, lubricants, antistatic agents, and whitening agents. Examples also include agents, colorants, conductive agents, release agents, surface treatment agents, viscosity modifiers, and flame retardants.

The viscosity of the present dispersion is preferably 50 to 1000 mPa·s, more preferably 75 to 500 mPa·s. In this case, not only the dispersibility of the powder dispersion is excellent, but also the coatability and the miscibility with the varnish of different polymers are excellent.
The thixo ratio of this dispersion is preferably 1.0 to 2.2, more preferably 1.4 to 2.0. In this case, not only is the dispersibility of the powder dispersion excellent, but the coatability of the powder dispersion is also good, and the homogeneity of the F layer is likely to be improved. In addition, the powder dispersion has a higher mixing property with the varnish of different polymers.

When this dispersion is applied to the surface of various substrates, it is possible to form an F layer having excellent surface smoothness and UV processability while suppressing the occurrence of powder falling when forming a layer (coating film).
The laminate of the present invention has a metal substrate layer and a layer (F layer) provided on the surface of the metal substrate layer and formed from the powder dispersion liquid.
Examples of the material of the metal substrate layer include copper, copper alloy, stainless steel, nickel, nickel alloy (including 42 alloy), aluminum, aluminum alloy, titanium, and titanium alloy.
The metal substrate layer is preferably composed of a metal foil such as rolled copper foil or electrolytic copper foil. The surface of such a metal foil may be subjected to rust-preventing treatment (oxide coating of chromate or the like) or roughening treatment.
The metal foil may have any thickness as long as it can exhibit a sufficient function in the use of the laminate. The thickness of the metal foil is not less than the ten-point average roughness of the surface thereof, and is preferably 2 to 40 μm. As the metal foil, a metal foil with a carrier comprising a carrier copper foil (thickness: 10 to 35 μm) and an ultrathin copper foil (thickness: 2 to 5 μm) laminated on the carrier copper foil via a release layer. May be used. Further, the thickness of the metal foil is preferably larger than the thickness of the F resin layer.

The ten-point average roughness of the surface of the metal foil is preferably 0.2 to 1.5 μm. In this case, the adhesiveness with the F layer tends to be good.
The metal foil may have any thickness as long as it can exhibit its function in the intended use of the laminate.
The surface of the metal foil may be treated with a silane coupling agent. In this case, the entire surface of the metal foil may be treated with the silane coupling agent, or a part of the surface of the metal foil may be treated with the silane coupling agent.

The laminate of the present invention has the F layer on at least one surface of the metal substrate layer. That is, the laminate may have the F layer on only one side of the metal substrate layer, or may have the F layer on both sides of the metal substrate layer.
The warp rate of the laminate is preferably 25% or less, more preferably 7% or less. In this case, the handleability when processing the laminated body into a printed board and the transmission characteristics of the obtained printed board are excellent.
The dimensional change rate of the laminate is preferably ±1% or less, more preferably ±0.2% or less. In this case, it is easy to process the laminated body into a printed board and further to make it into multiple layers.

The water contact angle of the surface of the F layer is preferably 70 to 100°, more preferably 70 to 90°. In this case, the adhesiveness between the F layer and another substrate is more excellent. When the above range is at least the lower limit value, the electrical characteristics when the laminate is processed into a printed board will be more excellent.
The thickness of the F layer is preferably 1 to 50 μm, more preferably 5 to 15 μm. Within this range, it is easy to balance the electrical characteristics when the laminated body is processed into a printed circuit board and the suppression of warpage of the laminated body. When the laminate has F layers on both sides of the metal substrate, the composition and thickness of the two F layers are preferably the same from the viewpoint of suppressing warpage of the laminate.
The thickness of the F layer is preferably 25 μm or less, more preferably 20 μm or less. The thickness of the F layer is preferably 1 μm or more. The dispersion contains the respective contents of the F polymer and the PI within a predetermined range, and even when the F layer having an arbitrary thickness is formed, a dense layer of the TFE polymer in which the PI is uniformly dispersed can be formed. As a result, it is possible to form an F layer having an arbitrary thickness having heat resistance, chemical resistance, and electric characteristics.
The relative dielectric constant of the F layer is preferably 2.0 to 3.5, more preferably 2.0 to 3.0. In this case, the laminated body can be preferably used for a printed circuit board or the like that requires a low dielectric constant.
The dielectric loss tangent of the F layer is preferably 0.003 or less.

The powder dispersion is preferably applied to the metal substrate by coating.
The coating method may be any method as long as it forms a stable wet film (liquid coating) of the powder dispersion liquid on the surface of the metal substrate after coating, such as a spray method, a roll coating method, a spin coating method, a gravure coating method, The microgravure coating method, gravure offset method, knife coating method, kiss coating method, bar coating method, die coating method, fountain Mayer bar method, and slot die coating method can be mentioned.
When the metal substrate is heated after applying the powder dispersion liquid, it is preferable to maintain the temperature in the low temperature region and distill off (ie, dry) the solvent. The temperature in the low temperature region (hereinafter, also referred to as “dry region”) is preferably 80° C. or higher and lower than 180° C., and more preferably 120 to 170° C. The temperature of the drying region means the temperature of the atmosphere during the drying.
The holding at the temperature in the low temperature region may be performed in one step, or may be performed in two or more steps at different temperatures.
Examples of the method for maintaining the temperature in the low temperature region include a method using an oven, a method using a ventilation drying furnace, and a method of irradiating heat rays such as infrared rays.

The atmosphere for maintaining the temperature in the low temperature region may be either under normal pressure or under reduced pressure. The atmosphere may be any of an oxidizing gas atmosphere, a reducing gas atmosphere, and an inert gas atmosphere.
Examples of the inert gas include helium gas, neon gas, argon gas, and nitrogen gas, and nitrogen gas is preferable.
Examples of the reducing gas include hydrogen gas.
Oxygen gas is mentioned as an oxidizing gas.

The atmosphere for maintaining the temperature in the low temperature region is preferably an atmosphere containing oxygen gas from the viewpoint of promoting the oxidative decomposition of the A polymer and further improving the adhesiveness of the F layer.
The oxygen gas concentration (volume basis) in the atmosphere containing oxygen gas is preferably 1×10 ² to 3×10 ⁵ ppm, more preferably 0.5×10 ³ to 1×10 ⁴ ppm. Within this range, it is easy to balance the oxidative decomposition of the A polymer and the suppression of oxidation of the metal substrate.
The time for maintaining the temperature in the low temperature region is preferably 0.1 to 10 minutes, more preferably 0.5 to 5 minutes.

In the method for producing a layered product of the present invention, the F polymer is further fired in the temperature region (hereinafter, also referred to as “firing region”) exceeding the holding temperature in the low temperature region to form the F layer on the surface of the metal substrate. Are preferably formed. The temperature of the firing region means the temperature of the atmosphere during firing.
It is considered that the formation of the F layer in the present invention proceeds because the powder particles are closely packed and the F polymer is fused. If the powder dispersion contains a thermofusible resin, an F layer made of a mixture of an F polymer and a soluble resin is formed. If the powder dispersion contains a thermosetting resin, the F polymer and the thermosetting resin are formed. An F layer composed of the cured product of is formed.

Examples of the firing method include a method using an oven, a method using a ventilation drying furnace, and a method of irradiating with heat rays such as infrared rays. In order to improve the surface smoothness of the F layer, pressure may be applied with a heating plate, a heating roll, or the like. As a heating method, a method of irradiating with far infrared rays is preferable because it can be fired in a short time and the far infrared ray furnace is relatively compact. The heating method may be a combination of infrared heating and hot air heating.
The effective wavelength band of far infrared rays is preferably 2 to 20 μm, and more preferably 3 to 7 μm from the viewpoint of promoting uniform fusion of the F polymer.

The atmosphere during firing may be either under normal pressure or under reduced pressure. The atmosphere during firing may be any of an oxidizing gas atmosphere, a reducing gas atmosphere, and an inert gas atmosphere. From the viewpoint of suppressing the oxidative deterioration of the metal substrate and the F layer to be formed, the reducing property is reduced. A gas atmosphere or an inert gas atmosphere is preferred.
Examples of the inert gas include helium gas, neon gas, argon gas, and nitrogen gas, and nitrogen gas is preferable.
Examples of the reducing gas include hydrogen gas.
Oxygen gas is mentioned as an oxidizing gas.

The atmosphere for firing is preferably a gas atmosphere composed of an inert gas and having a low oxygen gas concentration, and more preferably a gas atmosphere composed of nitrogen gas and having an oxygen gas concentration (volume basis) of less than 500 ppm. The oxygen gas concentration (volume basis) is particularly preferably 300 ppm or less. The oxygen gas concentration (volume basis) is usually 1 ppm or more. Within this range, further oxidative decomposition of the A polymer is suppressed, and the hydrophilicity of the F layer is easily improved.
The temperature of the firing region is preferably 250 to 400°C, more preferably 300 to 380°C.
The time of maintaining the temperature in the firing region is preferably 30 seconds to 5 minutes, more preferably 1 to 2 minutes.

The laminate of the present invention may be surface-treated on the surface of the F layer in order to control the linear expansion of the F layer and further improve the adhesiveness of the F layer.
As the surface treatment method for forming the surface of the F layer, annealing treatment, corona discharge treatment, atmospheric pressure plasma treatment, vacuum plasma treatment, UV ozone treatment, excimer treatment, chemical etching, silane coupling treatment, fine surface roughening treatment, etc. Can be mentioned.
The temperature in the annealing treatment is preferably 120 to 180°C.
The pressure in the annealing treatment is preferably 0.005 to 0.015 MPa.
The annealing time is preferably 30 to 120 minutes.

Examples of the plasma irradiation device in the plasma treatment include a high frequency induction system, a capacitive coupling type electrode system, a corona discharge electrode-plasma jet system, a parallel plate type, a remote plasma type, an atmospheric pressure plasma type and an ICP type high density plasma type. ..
Examples of the gas used for the plasma treatment include oxygen gas, nitrogen gas, rare gas (argon or the like), hydrogen gas, ammonia gas and the like, and rare gas, hydrogen gas or nitrogen gas is preferable. Specific examples of the gas used for the plasma treatment include argon gas, a mixed gas of hydrogen gas and nitrogen gas, and a mixed gas of hydrogen gas, nitrogen gas, and argon gas.

In the layered product of the present invention, the surface of the F layer has excellent adhesiveness, so that it can be easily and firmly bonded to another substrate.
Examples of other substrates include a heat resistant resin film, a prepreg that is a precursor of a fiber reinforced resin plate, a laminate having a heat resistant resin film layer, and a laminate having a prepreg layer.
The prepreg is a sheet-like substrate in which a base material (tow, woven cloth, etc.) of reinforcing fibers (glass fiber, carbon fiber, etc.) is impregnated with a thermosetting resin or a thermoplastic resin.
The heat resistant resin film is a film containing at least one kind of heat resistant resin, and may be a single layer film or a multilayer film.
Examples of the heat resistant resin include polyimide, polyarylate, polysulfone, polyallylsulfone, aromatic polyamide, aromatic polyetheramide, polyphenylene sulfide, polyallyl ether ketone, polyamideimide, liquid crystalline polyester, liquid crystalline polyesteramide. ..

In the laminate of the present invention, as a method of laminating another substrate on the surface of the F layer, a method of hot pressing the laminate and another substrate can be mentioned.
When the other substrate is a prepreg, the pressing temperature is preferably not higher than the melting temperature of the F polymer, more preferably 120 to 300°C. When the other substrate is a heat resistant resin film, the pressing temperature is preferably 310 to 400°C.
The hot pressing is particularly preferably performed at a vacuum degree of 20 kPa or less from the viewpoint of suppressing air bubble inclusion and suppressing deterioration due to oxidation.
Further, during hot pressing, it is preferable to raise the temperature after reaching the above vacuum degree. If the temperature is raised before reaching the above-mentioned degree of vacuum, the F layer is softened, that is, pressure-bonded in a state having a certain degree of fluidity and adhesiveness, which may cause bubbles.
The pressure in the hot press is preferably 0.2 to 10 MPa from the viewpoint of firmly adhering the F layer and the substrate while suppressing damage to the substrate.

INDUSTRIAL APPLICABILITY The laminate of the present invention and the multilayer laminate thereof can be used as a flexible copper-clad laminate or a rigid copper-clad laminate for manufacturing a printed board.
The printed circuit board of the present invention is, for example, a method of processing a metal substrate in the laminate of the present invention into a conductor circuit (pattern circuit) having a predetermined pattern by etching or the like, or an electrolytic plating method (semi-additive method) of the laminate of the present invention. (SAP method), modified semi-additive method (MSAP method), etc.) can be used to produce a printed circuit board from the laminate of the present invention.
In the production of a printed circuit board, after forming a pattern circuit, an interlayer insulating film may be formed on the pattern circuit, and a conductor circuit may be further formed on the interlayer insulating film. The interlayer insulating film may be formed by the present dispersion liquid.
In manufacturing a printed circuit board, a solder resist may be laminated on the pattern circuit. The solder resist may be formed by the present dispersion liquid.
In manufacturing a printed circuit board, a coverlay film may be laminated on the pattern circuit.

Although the powder dispersion liquid, the laminate, and the printed circuit board of the present invention have been described above, the present invention is not limited to the configurations of the above-described embodiments.
For example, the powder dispersion liquid, the laminate, and the printed circuit board of the present invention may have other arbitrary configurations added in the configurations of the above-described embodiments, respectively, and may be replaced with any configuration exhibiting the same function. It may have been done.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.
1. Preparation of each component [F polymer]
F polymer 1: a copolymer containing 98.0 mol%, 0.1 mol% and 1.9 mol% of units based on TFE, units based on NAH and units based on PPVE in this order (melting temperature: 300° C., 380 Melt viscosity at ℃: 3×10 ⁵ Pa·s)
F polymer 2: polymer containing 98.0 mol% and 2.0 mol% of units based on TFE and units based on PPVE in this order (melting temperature: 305° C., melt viscosity at 380° C.: 3×10 ⁵ Pa. s)
[powder]
-Powder 1: Powder 1 made of F polymer 1 having D50 of 2.6 µm and D90 of 7.1 µm
-Powder 2: Powder 2 made of F polymer 2 having D50 of 3.5 µm and D90 of 9.2 µm
Incidentally, D50 and D90 were measured by dispersing the powder in water using a laser diffraction/scattering type particle size distribution measuring device (“LA-920 measuring device” manufactured by Horiba Ltd.).

[PI varnish]
Varnish of polyimide precursor: 3,3′4,4′-biphenyltetracarboxylic dianhydride (BPDA) and p-phenylenediamine (PPD) copolymer (molar ratio=1:1) A solution of N-methyl-2-pyrrolidone (NMP) dissolved in 0.5 g/dL of this varnish, the concentration of which was adjusted with NMP so that the polyimide concentration was 0.5 g/dL. The inherent viscosity at 0° C. was 2.0 dL/g.
-Polyimide varnish: 3,3'4,4'-benzophenone tetracarboxylic dianhydride, 2,4-diaminotoluene, 3,3'4,4'-biphenyltetracarboxylic dianhydride, and 2 , A solution obtained by dissolving a block copolymer with 2-bis{4-(4-aminophenoxy)phenyl}propane (molar ratio = 1:1:1:1) in NMP. The logarithmic viscosity at 30° C. of the solution whose concentration was adjusted with NMP to be 0.5 g/dL was 1.2 dL/g.
[A polymer]
_{CH 2 = CHCOO (CH 2)} 4 OCF (CF 3) (C (CF (CF 3) 2) (= C (CF 3) 2) and _{CH 2 = CHCOO (CH 2 CH} 2 O) co with 8 OH Polymer (molar ratio=1:1)
The copolymer is a nonionic fluoropolyol (weight average molecular weight: about 10,000).

2. Preparation of powder dispersion (Example 1)
First, 47 parts by mass of NMP, 2.5 parts by mass of A polymer, and 50 parts by mass of powder 1 were put into a pot, and then zirconia balls were put into the pot. Then, the pot was rolled under the condition of 150 rpm×1 hour to disperse the powder 1 to obtain a mixed liquid.
Next, a polyimide varnish was added to this mixed solution while stirring the stirrer at a rotation speed of 500 rpm so that the amount of the polyimide (solid content) in the powder dispersion was 0.5% by mass, Powder dispersion A was prepared.
The mass ratio of the content of polyimide (PI) to the content of powder 1 (F polymer 1) is 0.01.

(Examples 2-7)
Powder dispersion B (Example 2), powder dispersion C (Example 3), powder dispersion D (Example 4), in the same manner as in Example 1 except that the type and amount (blending ratio) of each component were changed. Powder dispersion E (Example 5), powder dispersion F (Example 6) and powder dispersion G (Example 7) were obtained. The components of each powder dispersion are summarized in Table 1 below.

3. Measurement and evaluation (1)
3-1. Evaluation of Cohesion during Preparation Immediately after preparing each powder dispersion, the dispersibility of the powder dispersion was visually confirmed and evaluated according to the following criteria.
○ (Good): No aggregation is observed.
Δ (Fair): No precipitation was observed at the bottom of the pot, but fine aggregates were attached to the side wall.
X (Not possible): Agglomerated powder is deposited at the bottom of the pot.

3-2. Evaluation of Sedimentation Property after Storage Each powder dispersion was allowed to stand at room temperature for 1 month, and after 1 month, the pot was stirred, and the degree of redispersion was visually confirmed, and evaluated according to the following criteria.
◯ (Good): Uniform dispersion was achieved only by stirring the pot.
Δ (OK): Even dispersion, but some agglomerates.
X (Not possible): The sedimented aggregate becomes a solid and does not disperse.

3-3. Evaluation of powder drop Each of the powder dispersions was roll-to-roll coated by die coating on an electrolytic copper foil (“Fukuda Metal Foil & Powder Co., Ltd., “CF-T49A-DS-HD2”, thickness: 12 μm, Rzjis: 1.2 μm). The coating was applied to form a liquid film. This liquid coating was passed through a drying oven at 120° C. for 30 minutes and dried by heating to obtain a dried coating. The powder drop of the obtained dry film was evaluated according to the following criteria.
◯ (Good): No powder falling is observed on the entire surface of the dry film.
Δ (Fair): Falling powder is seen at the edge of the dry film.
Poor (poor): Powder drop is observed on the entire surface of the dry film.

3-4. Evaluation of Water Absorption First, the dry film obtained above was heated at 380° C. for 15 minutes in a nitrogen oven. Thereby, an F layer-attached copper foil in which the F layer was formed on the surface of the copper foil was obtained. The thickness of the F layer was 12 μm. Next, the copper foil with the F layer was etched with an aqueous solution of ferric chloride to remove the copper foil to obtain a simple F layer.
This F layer was pre-dried at 50° C. for 48 hours according to ASTM D570, and then immersed in pure water at 23° C. for 24 hours. The mass of the F layer before and after the immersion in pure water was measured, and the water absorption rate was calculated based on the following formula.
Water absorption rate (%)=(mass after immersion in water−mass after preliminary drying)/mass after preliminary drying×100

3-5. Measurement of transmittance of ultraviolet ray having wavelength of 355 nm With respect to the F layer, transmittance of ultraviolet ray having wavelength of 355 nm was measured using a spectrophotometer (“UV-3600” manufactured by Shimadzu Corporation).
3-6. Measurement of Adhesive Strength A copper foil with an F layer is cut out to a width of 1 cm, and the copper foil is peeled from the F layer by a tensile tester at an angle of 90° at a speed of 50 mm/min, and an adhesive force (kN/m) at that time Was measured.

3-7. Evaluation of UV processability Using a laser processing machine (esi5330), the F-layer-coated copper foil was irradiated with a UV-YAG laser having a wavelength of 355 nm so as to circulate on a circle having a diameter of 100 μm. As a result, circular through holes were formed in the copper foil with the F layer. The laser output was 1.5 W, the laser focus diameter was 25 μm, the number of turns on the circumference was 16, and the oscillation frequency was 40 kHz.
Then, a piece of copper foil with an F layer including a through hole was cut out and hardened with a thermosetting epoxy resin. Then, polishing was performed until the cross section of the through hole was exposed, and the cross section of the portion where the through hole was formed was observed with a microscope.
Then, in the cross section of the portion where the through hole was formed, the presence or absence of peeling between the copper foil and the F layer was confirmed and evaluated according to the following criteria.
◯: No peeling is observed at all.
Δ: Peeling with a length of less than 5 μm is observed.
X: Peeling with a length of 5 μm or more is observed.

3-8. Measurement of dielectric loss tangent A Fabry-Perot resonator and a vector network analyzer (manufactured by Keycom) were used to measure the dielectric loss tangent at 10 GHz for the F layer of the copper foil with the F layer.
The above results are shown in Table 1 below.

(Example 8)
Powder dispersion A is applied to the roughened surface of the same copper foil using a Mayer bar to form a wet film on the roughened surface, and the mixture is passed through a ventilation drying oven (furnace temperature: 100°C) for 1.5 minutes. The solvent was volatilized to form a coating layer. Further, the powder 1 (F-polymer 1) was passed through a far-infrared furnace (furnace temperature 370° C.) for 1 minute to melt and fire the powder 1 (F-polymer 1) to form an F layer (thickness: 4 μm) containing the F-polymer 1 on the surface. A copper foil with an F layer was obtained. The surface of the F layer of the copper foil with the F layer was subjected to plasma treatment (output: 4.5 kW, introduced gas: argon gas, introduced gas flow rate: 50 cm ³ /min, pressure: 50 mTorr, treatment time: 2 minutes).

FR-4 as a prepreg (“GEA-67N 0.2t (HAN)” manufactured by Hitachi Chemical Co., Ltd.) on the surface of the F layer of the copper foil with the F layer after plasma treatment; reinforcing fiber: glass fiber, matrix resin: epoxy resin , Thickness: 0.2 mm) and vacuum hot pressed (press temperature: 185° C., press pressure: 3.0 MPa, press time: 60 minutes) to obtain a laminate having a cured product layer of prepreg. ..
In the solder heat resistance test of floating this laminate on the solder bath, the phenomenon of swelling at the interface between the F layer and the cured product layer (swelling phenomenon) and the F layer The phenomenon that the copper foil floated (floating phenomenon) did not occur.

The powder dispersions A to D and the copper foil with the F layer obtained by using these were excellent in various properties. Further, when the dispersant A and the dispersant D were compared with each other, redispersion was possible, but the powder dispersion A was superior. It is considered that this is because the powder 1 contained in the powder dispersion A has a functional group, so that the interaction with the polyimide is enhanced and the dispersibility is further improved.

When comparing the copper foil with the F layer, in the copper foil with the F layer using the powder dispersion E, the powder easily fell off (powdered) during the formation of the F layer and adhered to the roll. On the other hand, in the copper foil with the F layer using the powder dispersion liquid A to which polyimide was added, it is considered that the polyimide became a binder for the powder particles and the falling of the powder was suppressed.
In addition, the copper foil with the F layer using the powder dispersion E did not contain a polyimide capable of absorbing light in the UV wavelength range, and thus the transmittance at 355 nm was 90%. Therefore, most of the UV laser is transmitted, and it is considered that the UV processability is deteriorated.

Further, in a laminate (a laminate of a copper foil with an F layer and a cured product of a prepreg), which is one embodiment of a printed circuit board material, the laminate manufactured from the powder dispersion A shows good results in a solder heat resistance test. It had heat resistance and chemical resistance.

Furthermore, for 100 parts by mass of the powder dispersion A, 1 part by mass of titanium oxide (particle size: 0.25 μm; “Taipec CR-50-2” manufactured by Ishihara Sangyo Co., Ltd.) coated with alumina and polyol. Was further blended to prepare a powder dispersion A′. The handleability of the powder dispersion A′ (the evaluation results of “3-1.” to “3-3.” above) was equivalent to that of the powder dispersion A. The 355 nm transmittance of the F layer of the copper foil with the F layer obtained by using this powder dispersion A′ was less than 5%, and it was confirmed that its UV absorption was further improved.

4. Production of film (Example 9)
On one side of a 50 μm-thick polyimide film (SKC Kolon PI, “FS-200”) 2, the powder dispersion A is applied by die coating, and it is placed in a ventilation drying furnace (furnace temperature: 140° C.) for 3 minutes. It was allowed to pass and the solvent was volatilized to form a coating layer. Furthermore, the powder dispersion liquid A was similarly coated on the other surface of the polyimide film 2 and the solvent was volatilized to form a coating layer. Further, this polyimide film 2 having coating layers formed on both sides is passed through a far-infrared furnace (furnace temperature: 370° C.) for 20 minutes, and the powder 1 is melted and fired to form the F layer 3 containing the polymer 1 on the polyimide. A film A having both surfaces of the film (PI layer) 2 was obtained. The thickness of each F layer was 25 μm.
(Example 10)
A film E was obtained in the same manner as in Example 9 except that the powder dispersion E was used instead of the powder dispersion A.

5. Measurement and evaluation (2)
Electrolytic copper foil (manufactured by Fukuda Metal Foil & Powder Co., Ltd., "CF-T49A-DS-HD2-12") 4 is placed on both sides of each film A and E, and pressed under vacuum at 340°C for 20 minutes. A double-sided copper-clad laminate 1 was obtained.
Except that the laser output was 1.5 W, the laser focus diameter was 25 μm, the number of revolutions on the circumference was 16 times, and the oscillation frequency was 40 kHz, each was performed in the same manner as in “3-7. The double-sided copper clad laminate 1 was irradiated with a UV-YAG laser to form circular through holes 5.

1 and 2 are photomicrographs of cross-sections around the through hole 5 in each double-sided copper-clad laminate 1.
In the double-sided copper clad laminate 1 obtained from the film A, since the F layer 3 contains polyimide, the UV processability is good. Therefore, as shown in the micrograph of FIG. 1, the degree of deterioration of the F layer 3 and the polyimide film (PI layer) 2 due to UV was suppressed around the through hole 5.
On the other hand, in the double-sided copper-clad laminate 1 obtained from the film E, since the F layer 3 does not contain polyimide, the UV irradiation time had to be lengthened to form the through holes 5. Therefore, as shown in the micrograph of FIG. 2, the degree of deterioration of the F layer 3 and the polyimide film (PI layer) 2 due to UV was great around the through hole 5.

Since the layer obtained by using the dispersant of the present invention has excellent electrical characteristics and UV processability, a laminate having such a layer is processed into an antenna part, a printed circuit board, an aircraft part, an automobile part, etc. Can be used.

1... Double-sided copper clad laminate, 2... Polyimide film (PI layer), 3... F layer, 4... Electrolytic copper foil, 5... Through hole, A, E... Film

Claims (14)

1. A powder of a tetrafluoroethylene-based polymer, a (meth)acrylate-based polymer, a polyimide precursor or polyimide, and a polar organic solvent, and the content of the tetrafluoroethylene-based polymer is 10 to 60% by mass. A powder dispersion, wherein the ratio of the content of the polyimide precursor or the content of the polyimide to the content of the tetrafluoroethylene-based polymer is 0.3 or less.
2. The powder dispersion according to claim 1, wherein the ratio is 0.005 or more and 0.1 or less.
3. When the solution was prepared by dissolving the polyimide precursor or the polyimide in N-methyl-2-pyrrolidone so as to have a concentration of 0.5 g/dL, the logarithmic viscosity at 30° C. of the solution was 0.2 to 3 dL. /G, The powder dispersion liquid according to claim 1 or 2.
4. 4. The aromatic polyimide precursor or the aromatic polyimide obtained by reacting an aromatic tetracarboxylic dianhydride with a diamine, according to claim 1, wherein the polyimide precursor or the polyimide is an aromatic polyimide precursor or an aromatic polyimide. Powder dispersion.
5. The powder according to any one of claims 1 to 4, wherein the mass ratio of the content of the (meth)acrylate polymer to the content of the tetrafluoroethylene polymer is 0.02 to 0.15. Dispersion.
6. The powder dispersion according to any one of claims 1 to 5, wherein the (meth)acrylate-based polymer includes a unit based on a (meth)acrylate having a hydroxyl group or an oxyalkylene group.
7. The powder dispersion according to any one of claims 1 to 6, wherein the (meth)acrylate-based polymer includes a unit based on a (meth)acrylate having a fluoroalkyl group or a fluoroalkenyl group.
8. The powder dispersion according to any one of claims 1 to 7, wherein the polar organic solvent is a cyclic ester, a cyclic ketone or a cyclic amide.
9. The powder dispersion liquid according to any one of claims 1 to 8, which further comprises an inorganic filler.
10. The powder according to any one of claims 1 to 9, further comprising an inorganic filler, wherein the mass ratio of the content of the inorganic filler to the content of the tetrafluoroethylene-based polymer is 0.3 or less. Dispersion.
11. 11. The tetrafluoroethylene-based polymer is a tetrafluoroethylene-based polymer containing units based on units based on perfluoro(alkyl vinyl ether), or polytetrafluoroethylene having a number average molecular weight of 200,000 or less. The powder dispersion liquid according to any one of 1.
12. The tetrafluoroethylene-based polymer has a polar functional group containing a unit based on perfluoro(alkyl vinyl ether), or a unit based on perfluoro(alkyl vinyl ether) is 2.0 to 5 with respect to all units. The powder dispersion according to any one of claims 1 to 11, which is a tetrafluoroethylene-based polymer having a polar functional group content of 0.0 mol%.
13. A laminate having a metal substrate layer and a polymer layer provided on the surface of the metal substrate layer and formed from the powder dispersion liquid according to any one of claims 1 to 12.
14. A printed circuit board obtained by processing the metal substrate layer of the laminate according to claim 13 into a pattern circuit.

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