Liquid composition, laminate using said liquid composition, and method for producing prepreg

Abstract

This liquid composition comprises: particles of a tetrafluoroethylene-based polymer; a polymer (P) that has a vinyl group or a vinylene group; and a nonaqueous dispersion medium. The polymer (P) is a polymer that has a nitrogen-containing heterocyclic structure and an etheric oxygen atom in the main chain, or a styrene-based polymer that has more than 2 but not more than 10 vinyl groups or vinylene groups in each molecule. The content of the particles of the tetrafluoroethylene-based polymer relative to the content of the polymer (P) is more than 0.33 in terms of the mass ratio. The liquid composition has a viscosity of 10,000 mPa or less.

Description

Liquid composition, laminate using said liquid composition, and method for producing prepreg

[0001] The present invention relates to a predetermined liquid composition containing a tetrafluoroethylene-based polymer, a method for producing a laminate having a layer containing a tetrafluoroethylene-based polymer using the liquid composition, and a method for producing a prepreg containing a tetrafluoroethylene-based polymer.

[0002] In recent years, in order to accommodate the increasing speed and frequency of mobile communication devices such as mobile phones, materials with high thermal conductivity, low linear expansion coefficient, low dielectric constant and low dielectric loss tangent are required for printed circuit boards of communication devices, and tetrafluoroethylene-based polymers with low dielectric constant and low dielectric loss tangent have attracted attention. Patent Document 1 proposes a curable composition containing a polymer having a specific structure and a small amount of tetrafluoroethylene-based polymer as a printed wiring board material. Patent Document 2 proposes a thermosetting resin composition containing a specific polyphenylene ether compound, an elastomer and specific amounts of tetrafluoroethylene-based polymer particles as a printed wiring board material.

[0003] International Publication No. 2022 / 210095 Japanese Patent Application Laid-Open No. 2022-161530

[0004] As printed wiring boards become increasingly dense, there is a demand for printed wiring boards that not only have excellent heat resistance and the above-mentioned electrical properties, but also excellent water resistance and adhesion between the conductive layer and the insulating layer, suppress peeling of fine conductive patterns from the insulating layer, and have excellent circuit formation properties. The present inventors have discovered that a low-viscosity, non-aqueous liquid composition containing a polymer having a specific structure and more than a predetermined amount of tetrafluoroethylene-based polymer particles, in which the polymers are highly dispersed, can form a polymer layer that has excellent heat resistance, electrical properties (low linear expansion coefficient, low dielectric constant, and low dielectric dissipation factor), adhesion to substrates such as conductive layers, and water resistance. They have also found that laminates and prepregs having such polymer layers possess the physical properties of tetrafluoroethylene-based polymers to a high degree and are useful as printed circuit board materials, etc., and have arrived at the present invention. An object of the present invention is to provide a liquid composition that can form a polymer layer containing a tetrafluoroethylene-based polymer and that has excellent electrical properties, heat resistance, water resistance, and adhesion to a substrate layer, a method for producing a laminate and a prepreg using the liquid composition, and a laminate and a prepreg having the polymer layer.

[0005] The present invention has the following aspects. [1] A liquid composition comprising particles of a tetrafluoroethylene-based polymer, a polymer (P) having a vinyl group or a vinylene group, and a non-aqueous dispersion medium, wherein the polymer (P) is a polymer having a nitrogen-containing heterocyclic structure and an etheric oxygen atom in the main chain, or a styrene-based polymer having more than 2 and not more than 10 vinyl groups or vinylene groups per molecule, wherein the content of the tetrafluoroethylene-based polymer particles relative to the content of the polymer (P) is greater than 0.33 in mass ratio, and the viscosity is 10,000 mPa or less. [2] A liquid composition comprising particles of a tetrafluoroethylene-based polymer, a polymer having a nitrogen-containing heterocyclic structure and an etheric oxygen atom in the main chain and a group having a vinyl group or a vinylene group, and a non-aqueous dispersion medium, wherein the content of the tetrafluoroethylene-based polymer particles relative to the content of the polymer is greater than 0.33 in mass ratio, and the viscosity is 10,000 mPa or less. [3] The liquid composition of [2], wherein the tetrafluoroethylene-based polymer contains a tetrafluoroethylene-based polymer having a carbonyl group-containing group and a melting temperature of 260°C or higher. [4] The liquid composition of [2] or [3], wherein the content of tetrafluoroethylene-based polymer particles is more than 15% by mass. [5] The liquid composition of any of [2] to [4], wherein the tetrafluoroethylene-based polymer particles have an average particle size of less than 10 μm. [6] The liquid composition of any of [2] to [5], wherein the polymer further has one or more aromatic hydrocarbon ring structures or alicyclic hydrocarbon structures in the main chain. [7] The liquid composition of any of [2] to [6], wherein the weight-average molecular weight of the polymer is in the range of 1,000 to 500,000. [8] The liquid composition of any of [2] to [7], wherein the non-aqueous dispersion medium is a hydrocarbon, a ketone, an amide, or an ester. [9] The liquid composition according to any one of [2] to [8], comprising a dispersion containing tetrafluoroethylene-based polymer particles dispersed in a non-aqueous dispersion medium, a polymer having a nitrogen-containing heterocyclic structure and an etheric oxygen atom in the main chain and a group containing an ethylenically unsaturated double bond, and a non-aqueous dispersion medium.

[10] A method for producing a laminate, comprising coating a surface of a base layer with the liquid composition of any one of [2] to [9] to form a coating layer made of the liquid composition on the surface of the base layer, and heating the base layer having the coating layer to obtain a laminate having the tetrafluoroethylene-based polymer and a polymer layer containing the polymer on the surface of the base layer.

[11] A laminate having the tetrafluoroethylene-based polymer and a polymer layer containing the polymer, formed from the liquid composition of any one of [2] to [9].

[12] A method for producing a prepreg, comprising impregnating a reinforcing fiber substrate with the liquid composition of any one of [2] to [9] and disposing the reinforcing fiber substrate.

[13] A prepreg formed from the liquid composition of any one of [2] to [9] and containing the tetrafluoroethylene-based polymer and the polymer.

[0006]

[14] A liquid composition comprising particles of a tetrafluoroethylene-based polymer, a styrene-based polymer having more than 2 and not more than 10 vinyl or vinylene groups per molecule, and a non-aqueous dispersion medium, and having a viscosity of 10,000 mPa or less.

[15] The liquid composition of

[14] , wherein the tetrafluoroethylene-based polymer comprises a tetrafluoroethylene-based polymer having a carbonyl group-containing group and a melting temperature of 260°C or higher.

[16] The liquid composition of

[14] or

[15] , wherein the content of the tetrafluoroethylene-based polymer particles is 10% by mass or more.

[17] The liquid composition of any of

[14] to

[16] , wherein the average particle size of the tetrafluoroethylene-based polymer particles is less than 10 μm.

[18] The liquid composition of any of

[14] to

[17] , wherein the styrene-based polymer contains units based on a divinyl aromatic compound and units based on a monovinyl aromatic compound.

[19] The liquid composition of any of

[14] to

[18] , wherein the number average molecular weight of the styrene-based polymer is in the range of 500 to 100,000.

[20] The liquid composition of any of

[14] to

[19] , wherein the styrene-based polymer comprises a styrene-based polymer having a vinyl group or vinylene group content of more than 2 and a styrene-based polymer having a vinyl group or vinylene group content of 2 or less.

[21] The liquid composition of any of

[14] to

[20] , wherein the content of the tetrafluoroethylene-based polymer particles relative to the content of the styrene-based polymer is a mass ratio of more than 0.33.

[22] The liquid composition of any of

[14] to

[21] , wherein the non-aqueous dispersion medium is a hydrocarbon, a ketone, an amide, or an ester.

[23] The liquid composition of any of

[14] to

[22] , comprising a dispersion containing tetrafluoroethylene-based polymer particles dispersed in a non-aqueous dispersion medium, a styrene-based polymer having more than 2 and not more than 10 vinyl or vinylene groups per molecule, and a non-aqueous dispersion medium.

[24] A method for producing a laminate, comprising applying the liquid composition of any of

[14] to

[23] to the surface of a substrate layer to form a coating layer made of the liquid composition on the surface of the substrate layer, and heating the substrate layer having the coating layer to obtain a laminate having a polymer layer containing the tetrafluoroethylene-based polymer and the styrene-based polymer on the surface of the substrate layer.

[25] A laminate having a polymer layer containing the tetrafluoroethylene-based polymer and the styrene-based polymer, formed from the liquid composition of any one of

[14] to

[23] .

[26] A method for producing a prepreg, comprising impregnating a reinforcing fiber substrate with the liquid composition of any one of

[14] to

[23] and disposing the substrate in the liquid composition.

[27] A prepreg, formed from the liquid composition of any one of

[14] to

[23] , comprising the tetrafluoroethylene-based polymer and the styrene-based polymer.

[0007] The present invention provides a composition capable of forming a polymer layer having high physical properties of a tetrafluoroethylene-based polymer and excellent electrical properties, heat resistance, water resistance, and adhesion to a substrate layer, as well as a laminate and a prepreg including the polymer layer. The laminate and prepreg including the polymer layer can be effectively used, for example, as a material for a printed wiring board.

[0008] The following terms have the following meanings. "Average particle size (D50)" is the volume-based cumulative 50% diameter of particles determined by laser diffraction / scattering. That is, particle size distribution is measured by laser diffraction / scattering, a cumulative curve is calculated with the total volume of the particle population set to 100%, and the particle size is the point on the cumulative curve where the cumulative volume is 50%. D50 of particles is determined by dispersing the particles in water and analyzing them by laser diffraction / scattering using a laser diffraction / scattering particle size distribution measuring device (LA-920 measuring device, manufactured by Horiba, Ltd.). "Average particle size (D90)" is the volume-based cumulative 90% diameter of particles determined in the same manner as D50. The specific surface area of ​​particles is a value calculated by measuring particles by gas adsorption (constant volume method) BET multipoint method, and is determined using a NOVA4200e (manufactured by Quantachrome Instruments). "Melting temperature" is the temperature corresponding to the maximum value of the melting peak of a polymer measured by differential scanning calorimetry (DSC). "Glass transition point (Tg)" is a value measured by analyzing a polymer by dynamic mechanical analysis (DMA). "Viscosity" is determined by measuring the composition using a Brookfield viscometer at 25°C and a rotation speed of 30 rpm. The measurement is repeated three times, and the average value of the three measured values ​​is used. "Thixotropy ratio" is the viscosity η of the composition measured at a rotation speed of 30 rpm. １ The viscosity η measured at a rotation speed of 60 rpm ２ The viscosity is calculated by dividing the viscosity by the average value of the three measurements. Each viscosity measurement is repeated three times, and the average of the three measurements is used. The "unit" in a polymer means an atomic group based on a monomer formed by polymerization of the monomer. The unit may be a unit formed directly by the polymerization reaction, or may be a unit in which a part of the unit is converted into a different structure by treating the polymer. Hereinafter, a unit based on monomer a will also be simply referred to as a "monomer a unit."

[0009] The present invention provides a liquid composition (hereinafter also referred to as "the composition") having a viscosity of 10,000 mPa or less, comprising particles (hereinafter also referred to as "F particles") of a tetrafluoroethylene-based polymer (hereinafter also referred to as "F polymer"), a polymer (P) having a vinyl group or a vinylene group, and a non-aqueous dispersion medium, wherein the polymer (P) is a polymer having a nitrogen-containing heterocyclic structure and an etheric oxygen atom in the main chain, or a styrene-based polymer having more than 2 but not more than 10 vinyl groups or vinylene groups per molecule, and wherein the mass ratio of the content of the F particles to the content of the polymer (P) exceeds 0.33.

[0010] The composition can be used to form a polymer layer that is excellent in electrical properties, heat resistance, water resistance, and adhesion to a substrate layer. Laminates and prepregs including such a polymer layer are excellent in physical properties such as heat resistance and electrical properties (low linear expansion coefficient, low dielectric constant, and low dielectric loss tangent) based on the tetrafluoroethylene-based polymer, and further have excellent water resistance and adhesion to a substrate layer.

[0011] The F polymer in the present invention is a polymer containing units (hereinafter also referred to as "TFE units") based on tetrafluoroethylene (hereinafter also referred to as "TFE"). The F polymer is preferably heat-fusible. Here, a heat-fusible polymer means a polymer at which there exists a temperature at which the melt flow rate becomes 1 to 1000 g / 10 min under a load of 49 N. The melting temperature of the F polymer is preferably 200°C or higher, more preferably 260°C or higher. The melting temperature of the F polymer is preferably 325°C or lower, more preferably 320°C or lower. In other words, the melting temperature of the F polymer is more preferably 260 to 320°C. In this case, the present composition is likely to have excellent processability, and the polymer layer formed from the present composition is likely to have excellent heat resistance.

[0012] The glass transition point of the F polymer is preferably 50°C or higher, more preferably 75°C or higher. The glass transition point of the F polymer is preferably 150°C or lower, more preferably 125°C or lower. The fluorine content of the F polymer is preferably 70% by mass or higher, more preferably 72 to 76% by mass. The surface tension of the F polymer is preferably 16 to 26 mN / m. The surface tension of the F polymer can be measured by placing a droplet of a mixture for wetting tension testing specified in JIS K 6768 (manufactured by Wako Pure Chemical Industries, Ltd.) on a flat plate made of the F polymer.

[0013] F polymer is preferably the polymer (ETFE) that comprises TFE unit and ethylene-based unit, the polymer that comprises TFE unit and propylene-based unit, the polymer (PFA) that comprises TFE unit and perfluoro(alkyl vinyl ether) (PAVE)-based unit (PAVE unit), the polymer (FEP) that comprises TFE unit and hexafluoropropylene-based unit, more preferably PFA and FEP, and even more preferably PFA.These polymers may further comprise units that are based on other comonomers.PAVE is preferably CF ２ = CFOCF ３ , C.F. ２ = CFOCF ２ CF ３ and CF ２ = CFOCF ２ CF ２ CF ３ (hereinafter also referred to as "PPVE") is preferred, and PPVE is more preferred.

[0014] The F polymer preferably has an oxygen-containing polar group, more preferably a hydroxyl group-containing group or a carbonyl group-containing group, and even more preferably a carbonyl group-containing group. In this case, the interaction between the polymer (P) and the F polymer is likely to be enhanced, and the above-mentioned mechanism of action is likely to be more easily manifested. The hydroxyl group-containing group is preferably a group containing an alcoholic hydroxyl group, such as -CF ２ CH ２ OH and -C(CF ３ ) ２OH is more preferred. The carbonyl group-containing group is a carboxyl group, an alkoxycarbonyl group, an amide group, an isocyanate group, a carbamate group (—OC(O)NH ２ ), acid anhydride residue (-C(O)OC(O)-), imide residue (-C(O)NHC(O)-, etc.), formyl group, halogenoformyl group, urethane group (-NHC(O)O-), carbamoyl group (-C(O)-NH ２ ), ureido group (-NH-C(O)-NH ２ ), an oxamoyl group (—NH—C(O)—C(O)—NH ２ ) and carbonate group (—OC(O)O—), and acid anhydride residues are more preferred. When the F polymer has an oxygen-containing polar group, the number of oxygen-containing polar groups in the F polymer is 1×10 ６ The number per unit is preferably 10 to 5000, more preferably 100 to 3000. The number of oxygen-containing polar groups in the F polymer can be quantified by the composition of the polymer or the method described in WO 2020 / 145133.

[0015] The oxygen-containing polar group may be contained in a unit derived from a monomer in the F polymer, or may be contained in a terminal group of the main chain of the F polymer, the former being preferred. Examples of the latter include an F polymer having an oxygen-containing polar group as a terminal group derived from a polymerization initiator, a chain transfer agent, etc., and an F polymer obtained by subjecting an F polymer to plasma treatment or ionizing radiation treatment.

[0016] The F polymer is preferably a polymer having an oxygen-containing polar group containing TFE units and PAVE units. The use of such an F polymer also facilitates the formation of spherulites with a relatively small radius, thereby increasing the surface roughness of the polymer layer formed from this composition. The F polymer is preferably a polymer having a carbonyl group-containing group containing TFE units and PAVE units, and more preferably a polymer containing TFE units, PAVE units, and units based on a monomer having a carbonyl group-containing group, with these units comprising, in this order, 90 to 99 mol%, 0.99 to 9.97 mol%, and 0.01 to 3 mol%, based on the total units. Specific examples of such F polymers include the polymers described in WO 2018 / 16644. Preferred monomers having a carbonyl group-containing group are itaconic anhydride, citraconic anhydride, and 5-norbornene-2,3-dicarboxylic anhydride (hereinafter also referred to as "NAH"), with NAH being more preferred.

[0017] The F particles contained in the composition are particles containing an F polymer, and are preferably made of an F polymer. The D50 of the F particles is preferably less than 10 μm. The F particles may be solid particles or non-hollow particles. The F particles may be secondary particles formed from nanometer-order fine particles. The D50 of the F particles is preferably 0.1 μm or more, and more preferably 1.0 μm or more. The D50 of the F particles is preferably 6 μm or less, and more preferably 5 μm or less. Furthermore, the D90 of the F particles is preferably 8 μm or less, and more preferably 6 μm or less. When the D50 and D90 of the F particles are within the above ranges, the above-mentioned mechanism of action is more likely to be exhibited. One type of F particles may be used, or two or more types may be used.

[0018] The specific surface area of ​​F particles is 1 to 25 m ２ / g, and 6 to 15 m ２ / g is more preferable. When the specific surface area of ​​the F particles is within the above range, it is considered that the F particle surfaces are easily wetted, and F particle aggregates are easily disintegrated, making it easier to realize the above-mentioned mechanism of action. Furthermore, the polymer layer formed from this composition is likely to have excellent adhesion to the substrate in addition to the physical properties inherent to the F polymer, such as heat resistance and electrical properties (low linear expansion coefficient, low dielectric constant, and low dielectric dissipation factor).

[0019] The content of F particles in the present composition is preferably 10 to 55% by mass.

[0020] The polymer (P) contained in the present composition is preferably a V polymer or an S polymer, which will be described later.

[0021] In the present composition, the content of the F polymer particles (F particles) relative to the polymer (P) is, in mass ratio, more than 0.33, preferably 0.35 or more, more preferably 0.5 or more, and the mass ratio is preferably 2 or less, more preferably 1 or less.

[0022] The non-aqueous dispersion medium contained in the present composition is preferably at least one selected from the group consisting of hydrocarbons, amides, ketones, and esters. Examples of hydrocarbons include linear or cyclic aliphatic hydrocarbons such as pentane, hexane, heptane, octane, nonane, decane, dodecane, cyclopentane, cyclohexane, methylcyclohexane, ethylcyclohexane, cyclooctane, cyclodecane, cyclododecane, liquid paraffin, limonene, dipentene, and myrcene; and aromatic hydrocarbons such as benzene, toluene, ethylbenzene, xylene, cumene, mesitylene (1,3,5-trimethylbenzene), cymene, diethylbenzene, and naphthalene. Examples of amides include N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylpropanamide, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, N,N-diethylformamide, hexamethylphosphoric triamide, and 1,3-dimethyl-2-imidazolidinone. Examples of ketones include acetone, methyl ethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, methyl n-pentyl ketone, methyl isopentyl ketone, 2-heptanone, cyclopentanone, cyclohexanone, and cycloheptanone. Examples of esters include methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, ethyl 3-ethoxypropionate, γ-butyrolactone, and γ-valerolactone.

[0023] These non-aqueous dispersion media may be used alone or in combination of two or more. When two or more are used in combination, there are no particular restrictions on the combination of non-aqueous dispersion media, but a mixture of at least one of aliphatic hydrocarbons and aromatic hydrocarbons classified as non-polar and at least one selected from ketones, esters, and amides classified as polar is preferred. For example, a mixture of aromatic hydrocarbons and amides, or a mixture of aromatic hydrocarbons and ketones can be used as the non-aqueous dispersion media. Note that the non-polar non-aqueous dispersion media refers to non-aqueous dispersion media having a Rohrschneider polarity parameter of 3.0 or less, and the polar non-aqueous dispersion media refers to non-aqueous dispersion media having a Rohrschneider polarity parameter of 4.0 or more. The content of the non-aqueous dispersion media in this composition is preferably 25% by mass or more, more preferably 40% by mass or more. The content of the non-aqueous dispersion media is preferably less than 70% by mass, more preferably 65% ​​by mass or less. The content of the non-aqueous dispersion medium in the present composition is preferably 60 to 180% by mass relative to the content of the F particles.

[0024] The composition may further contain a nonionic surfactant. Examples of nonionic surfactants include glycol surfactants, acetylene surfactants, silicone surfactants, and fluorine surfactants. When the composition contains the nonionic surfactant, the above-mentioned mechanism of action is more easily exhibited, and the dispersion stability and handleability of the F particles are likely to be excellent. Specific examples of nonionic surfactants include the "Ftergent" series (manufactured by Neos Corporation), the "Surflon" series (manufactured by AGC Seimi Chemical Co., Ltd.), the "Megafac" series (manufactured by DIC Corporation), the "Unidyne" series (manufactured by Daikin Industries, Ltd.), "BYK-347," "BYK-349," "BYK-378," "BYK-3450," "BYK-3451," "BYK-3455," and "BYK-3456" (manufactured by BYK Japan KK), "KF-6011," and "KF-6043" (manufactured by Shin-Etsu Chemical Co., Ltd.), and the "Tergitol" series (manufactured by The Dow Chemical Company, "Tergitol TMN-100X," etc.). One type of nonionic surfactant may be used, or two or more types may be used. When the composition further contains a nonionic surfactant, the amount thereof is preferably in the range of 1 to 15 parts by mass per 100 parts by mass of the composition.

[0025] The present composition may further contain inorganic particles. In this case, the polymer layer formed from the present composition is likely to have excellent electrical properties and low linear expansion. Examples of inorganic particles include silicon compounds such as quartz powder, silica, wollastonite, talc, silicon nitride, silicon carbide, and mica; nitrogen compounds such as boron nitride and aluminum nitride; metal oxides such as aluminum oxide, zinc oxide, titanium oxide, cerium oxide, beryllium oxide, magnesium oxide, nickel oxide, vanadium oxide, copper oxide, iron oxide, and silver oxide; carbon fibers; carbon allotropes such as graphite, graphene, and carbon nanotubes; and metals such as silver and copper. One type of inorganic particle may be used, or two or more types may be used in combination. The D50 of the inorganic particles is preferably 0.1 to 50 μm. The surfaces of the inorganic particles may be surface-treated with a silane coupling agent. When the present composition contains inorganic particles, the content of the inorganic particles in the composition is preferably 1 to 75 mass%.

[0026] The composition may further contain another resin different from the F polymer and the polymer (P). Such another resin may be contained in the composition as non-hollow particles, or may be dissolved or dispersed in a non-aqueous dispersion medium that constitutes the composition. Examples of the other resin include polyester resins such as liquid crystalline aromatic polyesters, polyimide resins, polyamide-imide resins, epoxy resins, maleimide resins, urethane resins, polyphenylene ether resins, polyphenylene oxide resins, and polyphenylene sulfide resins.

[0027] The present composition may further contain additives such as a thixotropic agent, a viscosity modifier, an antifoaming agent, a dehydrating agent, a plasticizer, a weathering agent, an antioxidant, a heat stabilizer, a lubricant, an antistatic agent, a whitening agent, a colorant, a conductive agent, a mold release agent, and a flame retardant.

[0028] The composition can be obtained by mixing F particles, a polymer (P), a non-aqueous dispersion medium, and, if necessary, a nonionic surfactant, inorganic particles, other resins, additives, etc. The composition can be obtained by mixing the F particles, the polymer (P), and the non-aqueous dispersion medium all at once, or by mixing them in multiple batches. Furthermore, when the nonionic surfactant, inorganic particles, other resins, additives, etc. are further mixed as needed, the order of mixing is not particularly limited. They can be mixed with the F particles or the polymer (P) in advance, added to the non-aqueous dispersion medium in advance and then mixed with the F particles or the polymer (P), or mixed when the F particles and the polymer (P) are mixed with the non-aqueous dispersion medium.

[0029] In particular, the present composition preferably comprises a dispersion containing F particles dispersed in a non-aqueous dispersion medium, a polymer (P), and a non-aqueous dispersion medium. In other words, the present composition preferably comprises a dispersion containing F particles dispersed in a non-aqueous dispersion medium and a mixed liquid obtained by mixing the polymer (P) and the non-aqueous dispersion medium. The present composition is also preferably obtained by mixing the dispersion with the mixed liquid. In this case, the above-mentioned mechanism of action is more likely to be exhibited. The mixed liquid obtained by mixing the polymer (P) and the non-aqueous dispersion medium may be a solution in which the polymer (P) is dissolved in the non-aqueous dispersion medium, or may be a mixed liquid in which at least a portion of the polymer (P) is dispersed without dissolving in the non-aqueous dispersion medium.

[0030] Examples of mixing devices for obtaining the present composition include agitators equipped with blades, such as a Henschel mixer, pressure kneader, Banbury mixer, and planetary mixer; grinding devices equipped with media, such as a ball mill, attritor, basket mill, sand mill, sand grinder, Dyno Mill, Dispermat, SC mill, spike mill, and agitator mill; and dispersing devices equipped with other mechanisms, such as a microfluidizer, nanomizer, ultimizer, ultrasonic homogenizer, dissolver, disper, high-speed impeller, thin film swirling high-speed mixer, planetary mixer, and V-type mixer.

[0031] The viscosity of the composition is 10,000 mPa·s or less, and more preferably 3,000 mPa·s or less. The viscosity of the composition is preferably 10 mPa·s or more, and more preferably 100 mPa·s or more. In this case, the composition has excellent coatability and is easily able to form a polymer layer of any desired thickness. Furthermore, when the composition has a viscosity within this range, the physical properties of the F polymer are easily expressed to a high degree in the polymer layer formed therefrom. The thixotropy ratio of the composition is preferably 1.0 to 3.0. In this case, the composition has excellent coatability and homogeneity, and is easily able to form a denser polymer layer.

[0032] A specific example of a suitable composition of the present invention is a liquid composition (hereinafter also referred to as "composition 1") that contains particles of an F polymer (F particles), a polymer having a nitrogen-containing heterocyclic structure and an etheric oxygen atom in the main chain and having a vinyl group or a vinylene group (hereinafter also referred to as "V polymer"), and a non-aqueous dispersion medium, in which the content of the F particles relative to the V polymer exceeds 0.33 in mass ratio and the viscosity is 10,000 mPa or less.

[0033] Composition 1 can be used to form a polymer layer that is excellent in electrical properties, heat resistance, water resistance, and adhesion to a substrate layer. Laminates and prepregs that include such a polymer layer are excellent in physical properties such as heat resistance and electrical properties (low linear expansion coefficient, low dielectric constant, and low dielectric dissipation factor) based on the tetrafluoroethylene polymer, and also have excellent water resistance and adhesion to a substrate layer. The reason why the polymer layer obtained from Composition 1 is excellent in electrical properties, heat resistance, and water resistance and adhesion to a conductive layer is not necessarily clear, but is thought to be as follows.

[0034] Composition 1 contains F particles, a V polymer, and a non-aqueous dispersion medium. The V polymer, which has an etheric oxygen atom in its main chain, is thought to increase the degree of freedom of its nitrogen-containing heterocyclic structure and vinyl or vinylene group, thereby promoting the dispersion of F particles in a non-aqueous dispersion medium and controlling the viscosity of Composition 1 itself. Therefore, the viscosity of Composition 1 is excellent for coatability during the formation of a laminate, as described below, and the F particles in the formed coating layer are likely to be densely and uniformly packed. Therefore, it is presumed that the polymer layer containing the F polymer and the V polymer obtained from the coating layer will have improved water resistance and adhesion to the substrate. This tendency is more pronounced when Composition 1 further contains a nonionic surfactant, as described below, when the F polymer has an oxygen-containing polar group, or when Composition 1 contains a mixture of a dispersion of F particles dispersed in a non-aqueous dispersion medium and a V polymer and a non-aqueous dispersion medium.

[0035] The content of F particles in Composition 1 is preferably 15% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more. The content of F particles is preferably 55% by mass or less, and even more preferably 50% by mass or less.

[0036] The V polymer contained in the present composition 1 is a polymer having a nitrogen-containing heterocyclic structure and an etheric oxygen atom in the main chain and a group having a vinyl group or a vinylene group, and is preferably a polymer having a main chain with the following structure and a group having a vinyl group or a vinylene group at the terminal: -[R ２ -O-R １ —O]— (i) In formula (i), R １ represents a divalent organic group, R ２ represents a divalent nitrogen-containing heteroaromatic ring.

[0037] R ２ Examples of the divalent nitrogen-containing heteroaromatic ring represented by the formula (I) include a pyrrole ring, a pyridine ring, a pyrimidine ring, a pyrazine ring, a pyridazine ring, a triazine ring, a quinoline ring, an isoquinoline ring, a quinoxaline ring, a phthalazine ring, a quinazoline ring, a naphthyridine ring, a carbazole ring, an acridine ring, and a phenazine ring. Among these, a pyrimidine ring is preferred. The positions of the two bonds (bonds bonded to oxygen atoms) bonded to the nitrogen-containing heteroaromatic ring are not particularly limited, but meta positions are preferred. The divalent nitrogen-containing heteroaromatic ring may have a substituent, and examples thereof include a halogen atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms, a monovalent halogenated hydrocarbon group having 1 to 20 carbon atoms, a nitro group, a cyano group, an amino group, and a salt of an amino group.

[0038] Examples of the group having a vinyl group or a vinylene group include a vinyl group, an allyl group, an isopropenyl group, a 2-vinylbenzyl group, a 3-vinylbenzyl group, a 4-vinylbenzyl group, a 2-allylphenyl group, a 2-methoxy-4-allylphenyl group, a 3-isopropenylphenyl group, a 4-isopropenylphenyl group, and a 4-(1-propenyl)-2-methoxyphenyl group.

[0039] The V polymer preferably further has at least one aromatic hydrocarbon ring structure or alicyclic hydrocarbon structure in the main chain. When the V polymer has an aromatic hydrocarbon ring structure in the main chain, in detail, R １ The divalent organic group represented by the formula (I) preferably has the following structure: ３ -[Ar １ -L-] ｙ -Ar ２ -R ４ -...(ii) In formula (ii), R ３ and R ４ each independently represents a single bond, a methylene group, or an alkylene group having 2 to 4 carbon atoms. １ and Ar ２ each independently represents an aromatic hydrocarbon group; L is a single bond, —O—, —S—, —N(R ５ )-, -C(O)-, -C(O)-O-, -C(O)-NH-, -S(O)-, -S(O)2-, -P(O)-, or a divalent organic group. ５ represents a hydrogen atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms, or a monovalent halogenated hydrocarbon group having 1 to 20 carbon atoms. y represents an integer of 0 to 5. When y is 2 or more, a plurality of Ar １ and L may be the same or different. １ and Ar ２ Examples of the aromatic hydrocarbon group represented by include aromatic hydrocarbon groups having 6 to 30 carbon atoms, preferably a phenyl group, a naphthyl group, or an anthryl group, and more preferably a phenyl group or a naphthyl group. Such aromatic hydrocarbon groups may have a substituent, and examples thereof include a halogen atom; a monovalent hydrocarbon group having 1 to 20 carbon atoms, a monovalent halogenated hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylthio group having 1 to 20 carbon atoms; a nitro group, a cyano group, a hydroxy group; a primary, secondary, or tertiary amino group, a carboxy group, a sulfonic acid group, a phosphonic acid group, a phosphate group, or a salt thereof.

[0040] When the V polymer has an alicyclic hydrocarbon structure in its main chain, examples of the alicyclic hydrocarbon structure include alicyclic hydrocarbon structures containing at least one alicyclic hydrocarbon group selected from the group consisting of cyclopentane-1,1-diyl group, cyclohexane-1,1-diyl group, 3,3,5-trimethylcyclohexane-1,1-diyl group, cyclopentene-3,3-diyl group, cyclohexene-3,3-diyl group, cyclooctane-1,1-diyl group, cyclodecane-1,1-diyl group, and cyclododecane-1,1-diyl group. Note that the hydrogen atoms of the alicyclic hydrocarbon group may be substituted with a hydrocarbon group having 1 to 20 carbon atoms.

[0041] V polymer is R １ a monomer comprising a unit R ２ The polymer can be produced by heating a monomer containing a vinyl or vinylene unit, a monomer that forms a group having a vinyl group or vinylene group at its terminal, and, if necessary, a monomer that further derives other structural units, together with an alkali metal or an alkali metal compound in an organic solvent, and is also available as a commercially available polymer.

[0042] The V polymer preferably has a weight average molecular weight in the range of 1,000 to 500,000, more preferably 2,000 to 500,000, and even more preferably 3,000 to 100,000, as calculated using standard polystyrene standards by gel permeation chromatography (GPC).

[0043] In Composition 1, the mass ratio of the F polymer particles (F particles) to the V polymer is greater than 0.33, preferably 0.35 or greater, and more preferably 0.5 or greater. This mass ratio is preferably 2 or less, and more preferably 1 or less. When the F particle content relative to the V polymer is within this range, not only is the above-described mechanism of action more readily manifested, but the physical properties of the F polymer are also more readily manifested in the polymer layer obtained from Composition 1.

[0044] The non-aqueous dispersion medium contained in Composition 1 is the same as the non-aqueous dispersion medium contained in the composition described above, including the range of preferred embodiments. Composition 1 may further contain a nonionic surfactant. The nonionic surfactant that may be contained in Composition 1 is the same as the nonionic surfactant that may be contained in the composition described above, including the range of preferred embodiments. Composition 1 may further contain inorganic particles. The inorganic particles that may be contained in Composition 1 are the same as the inorganic particles that may be contained in the composition described above, including the range of preferred embodiments. % by mass is preferred. Composition 1 may further contain another resin different from the F polymer and the V polymer. Such other resins are the same as the other resins that may be contained in the composition described above, including the range of preferred embodiments. Composition 1 may further contain additives such as a thixotropic agent, a viscosity modifier, an antifoaming agent, a dehydrating agent, a plasticizer, a weathering agent, an antioxidant, a heat stabilizer, a lubricant, an antistatic agent, a brightener, a colorant, a conductive agent, a mold release agent, and a flame retardant.

[0045] The viscosity of composition 1 is 10,000 mPa·s or less, and more preferably 3,000 mPa·s or less. The viscosity of composition 1 is preferably 10 mPa·s or more, and more preferably 100 mPa·s or more. In this case, composition 1 has excellent coatability and is easily able to form a polymer layer of any desired thickness. Furthermore, composition 1 having a viscosity within this range is likely to highly exhibit the physical properties of the F polymer in the polymer layer formed therefrom. The thixotropy ratio of composition 1 is preferably 1.0 to 3.0. In this case, composition 1 has excellent coatability and homogeneity, and is likely to form a denser polymer layer.

[0046] A specific example of a suitable composition of the present invention is a liquid composition (hereinafter also referred to as "composition 2") that contains particles of an F polymer (F particles), a styrene-based polymer having more than 2 and not more than 10 vinyl groups or vinylene groups per molecule (hereinafter also referred to as "S polymer"), and a non-aqueous dispersion medium, and has a viscosity of 10,000 mPa or less.

[0047] Composition 2 can be used to form a polymer layer that is excellent in electrical properties, heat resistance, water resistance, and adhesion to a substrate layer. Laminates and prepregs including such a polymer layer are excellent in physical properties such as heat resistance and electrical properties (low linear expansion coefficient, low dielectric constant, and low dielectric dissipation factor) based on the tetrafluoroethylene polymer, and also have excellent water resistance and adhesion to a substrate layer. The reason why the polymer layer obtained from Composition 2 is excellent in electrical properties, heat resistance, and water resistance and adhesion to a conductive layer is not necessarily clear, but is thought to be as follows.

[0048] Composition 2 contains F particles, an S polymer, which is the specific styrene-based polymer described above, and a non-aqueous dispersion medium. It is believed that the S polymer has a specific range of vinyl groups or vinylene groups per molecule, which promotes dispersion of the F particles in the non-aqueous dispersion medium, acts as a stabilizer for the dispersion state, and controls the viscosity of Composition 2 itself. Therefore, the viscosity of Composition 2 is excellent for coatability during the formation of a laminate, as described below, and the F particles in the formed coating layer are likely to be densely and uniformly packed. Therefore, it is believed that the polymer layer containing the F polymer and the S polymer obtained from the coating layer will have improved water resistance and adhesion to the substrate. This tendency becomes more pronounced when composition 2 further contains a nonionic surfactant as described below, when the F polymer has an oxygen-containing polar group, when composition 2 contains a dispersion in which F particles are dispersed in a non-aqueous dispersion medium and a mixed liquid in which an S polymer and a non-aqueous dispersion medium are mixed, or when the S polymer contains a styrene-based polymer having a vinyl group or vinylene group content of more than two and a styrene-based polymer having a vinyl group or vinylene group content of two or less.

[0049] The content of F particles in Composition 2 is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more. The content of F particles is preferably 55% by mass or less, and even more preferably 50% by mass or less.

[0050] The S polymer contained in Composition 2 is a styrene-based polymer having more than two but not more than 10 vinyl or vinylene groups per molecule. The S polymer preferably contains units based on a divinyl aromatic compound and units based on a monovinyl aromatic compound. Examples of divinyl aromatic compounds include divinylbenzene, divinylnaphthalene, and divinylbiphenyl; or isomer mixtures thereof. These compounds may be used alone or in combination of two or more. Of these, divinylbenzene (m-isomer and p-isomer) or isomer mixtures thereof are preferred from the viewpoint of the moldability and ease of curing of the S polymer. Examples of monovinyl aromatic compounds include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o,p-dimethylstyrene, o-ethylvinylbenzene, m-ethylvinylbenzene, p-ethylvinylbenzene, vinylnaphthalene, vinylbiphenyl, indene, acenaphthylene, benzothiophene, and coumarone; or isomer mixtures thereof. These compounds may be used alone or in combination of two or more. Among these, from the viewpoints of solubility, compatibility, and processability of the S polymer in a non-aqueous dispersion medium, preferred monovinyl aromatic compounds are styrene, ethylvinylbenzene, ethylvinylbiphenyl, ethylvinylnaphthalene, indene, or an isomer mixture thereof, and more preferred are styrene, ethylvinylbenzene, indene, or an isomer mixture thereof.

[0051] The S polymer may further contain units based on other monomers in addition to units based on a divinyl aromatic compound and units based on a monovinyl aromatic compound, as long as the effects of the present invention are not impaired. Examples of such other monomers include olefin compounds, conjugated diene compounds, and trivinyl aromatic compounds. Examples of olefin compounds include α-olefins having 2 to 20 carbon atoms, such as ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decane, 1-dodecane, 4-methyl-1-pentene, and 3,5,5-trimethyl-1-hexene; and cyclic monoolefins having 5 to 20 carbon atoms, such as norbornene and cyclopentene. Examples of conjugated diene compounds include butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 1,3-hexadiene, and 1,3-heptadiene. Among these, butadiene and isoprene are preferred from the viewpoints of reactivity with vinyl aromatic compounds and easy availability. Examples of trivinyl aromatic compounds include 1,3,5-trivinylbenzene and 1,3,5-trivinylnaphthalene. These may be used alone or in combination of two or more.

[0052] In the S polymer, at least a portion of the units based on the divinyl aromatic compound may form a crosslinked structure.

[0053] The S polymer may further contain functional groups such as amino groups, alkoxysilyl groups, and hydroxyl groups. These functional groups may be derived from a polymerization initiator or may be modified with a modifying agent. When the S polymer contains the above-mentioned functional groups, the average number of functional groups per molecule is preferably 1.5 or more, and more preferably in the range of 1.5 to 20. Here, the average number of functional groups per molecule can be determined to be 1.5 or more if, for example, the value obtained by dividing the number average molecular weight of the S polymer by the functional group equivalent is 1.5 or more.

[0054] The S polymer preferably has a number average molecular weight in the range of 500 to 100,000, more preferably 1,000 to 30,000, as calculated using standard polystyrene standards by gel permeation chromatography (GPC). The content of units based on a monovinyl aromatic compound in the S polymer is preferably 98% by mass or less, more preferably 70% by mass or less. The content of units based on a monovinyl aromatic compound in the S polymer is preferably 10% by mass or more. When the content of units based on a monovinyl aromatic compound is within the above range, the mechanical properties of the polymer layer formed from composition 2 and its adhesion to a substrate are likely to be improved.

[0055] The S polymer has more than 2 but not more than 10 vinyl or vinylene groups per molecule. Having the vinyl or vinylene group content within the above range facilitates obtaining a polymer layer containing the F polymer (described below) with sufficient crosslinking density. The fact that the S polymer has more than 2 but not more than 10 vinyl or vinylene groups per molecule can be calculated by quantifying the amount of vinyl or vinylene groups per number average molecular weight in the S polymer, as follows:

[0056] The amount of vinyl groups based on a divinyl aromatic compound (e.g., divinylbenzene) per number average molecular weight in the S polymer is calculated by multiplying the number average molecular weight (Mn) by gel permeation chromatography using standard polystyrene equivalents, １ The vinyl group content can be calculated by comparing the vinyl group content based on the divinyl aromatic compound obtained by H-NMR measurement. For example, １ From the peak areas obtained by H-NMR measurement, if the vinyl group content based on divinylbenzene units in the S polymer is 3.2% by mass, and Mn by GPC measurement is 2100, the molecular weight of vinyl groups based on divinylbenzene units in the number average molecular weight is the product of these, 67.5, which is divided by the formula weight of the vinyl groups, 27, to obtain 2.5. In other words, the vinyl group content based on divinylbenzene units per Mn in the S polymer can be calculated to be 2.5. １ The assignment of peaks obtained by H-NMR measurement, １The method for determining the composition of an S-polymer from a comparison of peak areas obtained by H-NMR measurement is well known. In this specification, the content of divinylbenzene units in an S-polymer is determined by the ratio of the number of vinyl groups based on the divinylbenzene units to the number of vinyl groups based on the divinylbenzene units. １ It is determined from the peak intensity in H-NMR measurement. That is, the content of divinylbenzene units is determined from the vinyl group content based on the divinylbenzene unit, assuming that one vinyl group is based on one divinylbenzene unit in the S polymer.

[0057] When the S polymer further contains units based on the above-mentioned other monomers, the units based on the olefin compound are preferably 10% by mass or more, more preferably 20% by mass or more, based on the total amount of monomer units in the S polymer. The units based on the olefin compound are preferably 90% by mass or less, based on the total amount of monomer units in the S polymer. Furthermore, it is more preferable that the total of the units based on the olefin compound, vinyl aromatic compound, and divinylaromatic compound is 100% by mass. The units based on the conjugated diene compound and the units based on the trivinyl aromatic compound are preferably less than 30 mol% based on the total amount of monomer units in the S polymer.

[0058] The S polymer can be produced by the methods described in, for example, JP-A-2009-161743 and JP-A-2010-280771, and is also available as a commercially available polymer.

[0059] The S polymer preferably includes a styrene-based polymer having more than two vinyl or vinylene groups and a styrene-based polymer having two or less vinyl or vinylene groups. In other words, the S polymer "having more than two and no more than 10 vinyl or vinylene groups per molecule" in this specification is preferably a mixture of a styrene-based polymer having more than two vinyl or vinylene groups and a styrene-based polymer having two or less vinyl or vinylene groups as a result of the molecular weight distribution width. When the S polymer in composition 2 is the above-mentioned mixture, it is easy to achieve a high level of balance between the effect of improving the dispersibility of F particles in the liquid composition and the physical properties such as hardness of the molded product obtained from the composition. The method for quantifying the amount of vinyl or vinylene groups per number average molecular weight in the S polymer is as described above.

[0060] In the present composition 2, the content of the F polymer particles (F particles) relative to the S polymer is preferably a mass ratio of more than 0.33, preferably 0.35 or more, and more preferably 0.5 or more. The mass ratio is preferably 2 or less, more preferably 1 or less. When the content of the F particles relative to the S polymer is within the above range, not only is the above-mentioned mechanism of action more likely to be exhibited, but also the physical properties of the F polymer are more likely to be exhibited to a high degree in the polymer layer obtained from the present composition 2.

[0061] The non-aqueous dispersion medium contained in Composition 2 is the same as the non-aqueous dispersion medium contained in the composition described above, including the range of preferred embodiments. Composition 2 may further contain a nonionic surfactant. The nonionic surfactant that may be contained in Composition 2 is the same as the nonionic surfactant that may be contained in the composition described above, including the range of preferred embodiments. Composition 2 may further contain inorganic particles. The inorganic particles that may be contained in Composition 2 are the same as the inorganic particles that may be contained in the composition described above, including the range of preferred embodiments. % by mass is preferred. Composition 2 may further contain another resin different from the F polymer and the V polymer. Such other resins are the same as the other resins that may be contained in the composition described above, including the range of preferred embodiments. Composition 2 may further contain additives such as a thixotropic agent, a viscosity modifier, an antifoaming agent, a dehydrating agent, a plasticizer, a weathering agent, an antioxidant, a heat stabilizer, a lubricant, an antistatic agent, a brightener, a colorant, a conductive agent, a mold release agent, and a flame retardant.

[0062] The present invention also relates to a method for producing a laminate, which comprises coating the surface of a substrate layer with the present composition to form a coating layer comprising the present composition on the surface of the substrate layer, and heating the substrate layer having the coating layer to obtain a laminate having a polymer layer (hereinafter also referred to simply as a "polymer layer") comprising an F polymer and a polymer (P) on the surface of the substrate layer. In this method, the present composition is first coated on the substrate layer to form a coating layer comprising the present composition on the surface of the substrate layer. Examples of methods for coating the present composition include coating methods, droplet ejection methods, and immersion methods, with roll coating, knife coating, bar coating, die coating, and spraying methods being preferred.

[0063] The substrate layer is preferably a heat-resistant substrate. Examples of the heat-resistant substrate include metal substrates such as metal foils of copper, nickel, aluminum, titanium, and alloys thereof; heat-resistant resin films such as polyimide, polyamide, polyetheramide, polyphenylene sulfide, polyaryl ether ketone, polyamideimide, liquid crystal polymers such as liquid crystal polyester, and tetrafluoroethylene-based polymers other than F polymers such as polytetrafluoroethylene; prepreg substrates (precursors of fiber-reinforced resin substrates), ceramic substrates such as silicon carbide, aluminum nitride, and silicon nitride; and glass substrates. Among these, the heat-resistant substrate is preferably a metal substrate such as metal foils of copper, nickel, aluminum, titanium, and alloys thereof.

[0064] The shape of the substrate may be flat, curved, or uneven. The substrate may be in the form of a foil, plate, film, or fiber. In this method, the substrate layer may be a long substrate. This is preferable from the viewpoint of improving productivity, since a roll-to-roll process can be applied and the laminate of the present invention, described below, can be produced as a long rolled product. The ten-point average roughness of the substrate surface is preferably 0.01 to 0.05 μm. The substrate surface may be surface-treated with a silane coupling agent or may be plasma-treated. Preferred examples of such silane coupling agents include silane coupling agents having functional groups such as 3-aminopropyltriethoxysilane, vinyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-isocyanatopropyltriethoxysilane.

[0065] Next, the substrate layer having the coating layer is heated to obtain a laminate having a polymer layer containing the F polymer and polymer (P) on the surface of the substrate layer. First, the substrate layer having the coating layer is heated to remove the non-aqueous dispersion medium constituting the present composition. Heating to remove the non-aqueous dispersion medium is preferably performed at 100 to 200°C for 0.1 to 30 minutes. In this heating, the dispersion medium does not need to be completely removed; it is sufficient to remove it to the extent that the layer formed by the packing of the F particles can maintain a free-standing film. Furthermore, during heating, air may be blown onto the substrate to promote removal of the non-aqueous dispersion medium by air drying. Next, heating is performed to bake the F polymer. Heating to bake the F polymer is preferably performed at a temperature range above the melting temperature of the F polymer, specifically, at 340 to 400°C for 0.1 to 30 minutes.

[0066] Examples of heating devices for each heating method include an oven and a ventilated drying furnace. The heat source in the device may be a contact-type heat source (hot air, hot plate, etc.) or a non-contact-type heat source (infrared, etc.). Each heating method may be performed under normal pressure (atmospheric pressure) or under reduced pressure. The atmosphere for each heating method may be either an air atmosphere or an inert gas atmosphere (helium gas, neon gas, argon gas, nitrogen gas, etc.). In this manner, a polymer layer containing the F polymer and the polymer (P) is formed on the surface of the substrate layer to obtain a laminate. There are no particular restrictions on the ratio of the thickness of the polymer layer to the thickness of the substrate layer, but it is usually preferably 0.7 to 2.0.

[0067] The polymer layer is formed through the steps of coating the present composition on a substrate layer and heating. These steps may be performed once each, or may be repeated two or more times. For example, the present composition may be coated on the surface of a substrate layer to obtain a coating layer, a polymer layer may be formed by heating, and the present composition may be further coated on the surface of the polymer layer to form a coating layer, and a second polymer layer may be formed by heating. Alternatively, the present composition may be coated on the surface of a substrate layer to obtain a coating layer, and after the non-aqueous dispersion medium is removed by the first heating described above, the present composition may be further coated on the surface, and a polymer layer may be formed by each of the heating described above.

[0068] The composition may be disposed on only one surface of the substrate layer, or may be disposed on both surfaces of the substrate layer. In the former case, a laminate having a substrate layer and a polymer layer on one surface of the substrate layer is obtained, while in the latter case, a laminate having a substrate layer and polymer layers on both surfaces of the substrate layer is obtained. By separating the substrate layer from the laminate, a film or sheet containing the F polymer and the polymer (P) is obtained.

[0069] Suitable specific examples of the laminate include a metal clad laminate having a metal foil and a polymer layer on at least one surface of the metal foil, and a multilayer film having a polyimide film and polymer layers on both surfaces of the polyimide film.

[0070] The thickness of the polymer layer is preferably 25 μm or more, more preferably 30 μm or more, and even more preferably 50 μm or more. The thickness of the polymer layer is preferably 300 μm or less. The dielectric constant of the polymer layer is preferably 2.4 or less, more preferably 2.0 or less. The dielectric constant is preferably greater than 1.0. The dielectric dissipation factor of the polymer layer is preferably 0.0022 or less, more preferably 0.0020 or less. The dielectric dissipation factor is preferably greater than 0.0010. The thermal conductivity of the polymer layer is preferably 1 W / m·K or more, more preferably 3 W / m·K or more. The thermal conductivity of the polymer layer refers to the thermal conductivity in the in-plane direction of the polymer layer.

[0071] The linear expansion coefficient of the polymer layer is preferably 100 ppm / °C or less, more preferably 80 ppm / °C or less. The lower limit of the linear expansion coefficient of the F layer is 30 ppm / °C. The linear expansion coefficient refers to the value measured for a test piece in the range of 25°C or more and 260°C or less according to the measurement method specified in JIS C 6471:1995. The peel strength between the polymer layer and the substrate layer is preferably 10 N / cm or more, more preferably 15 N / cm or more. The peel strength is preferably 100 N / cm or less.

[0072] The present invention also relates to a laminate having a polymer layer formed from the present composition. In such a laminate, the substrate layer is preferably a heat-resistant substrate, and the heat-resistant substrate is more preferably a metal foil or a heat-resistant resin film. Details of the heat-resistant substrate, metal foil, or heat-resistant resin film are the same as those described above in the description of the present method. Furthermore, such a laminate may have a polymer layer on one surface or both surfaces of the substrate layer. The preferred ranges of the thickness, dielectric constant, dielectric loss tangent, thermal conductivity, linear expansion coefficient, and peel strength between the polymer layer and the substrate layer in such a laminate are the same as the preferred ranges of the thickness, dielectric constant, dielectric loss tangent, thermal conductivity, linear expansion coefficient, and peel strength between the polymer layer and the substrate layer in the laminate formed from the present composition by the above-mentioned production method.

[0073] The present invention also relates to a method for producing a prepreg, in which the present composition is impregnated into a reinforcing fiber substrate and then disposed thereon. Examples of reinforcing fiber substrates include woven or nonwoven fiber substrates primarily composed of inorganic fibers such as glass fiber, carbon fiber, silicon carbide fiber, silicon nitride fiber, alumina fiber, silicon carbide fiber, and boron fiber; and organic fibers such as cellulose fiber, aromatic polyamide fiber, polyaramid fiber, polyparaphenylene benzoxazole fiber, polyphenylene sulfide fiber, polyester fiber, polyimide fiber, acrylic fiber, and fluororesin fiber. The present composition can be impregnated (or applied) into the reinforcing fiber substrate by a method known in the art, such as an impregnation method, a coating method using various coaters, or a spraying method, and then disposed thereon, followed by heating to produce a prepreg containing a polymer including the F polymer and the polymer (P).

[0074] The details of the heating after the present composition is impregnated into the reinforcing fiber substrate and placed thereon are the same as those of the heating in the manufacturing method of the laminate of the present invention described above, i.e., the heating for removing the non-aqueous dispersion medium constituting the present composition and the heating for baking the F polymer. The present invention also includes a prepreg formed from the present composition, which contains the F polymer and polymer (P), in other words, which has a polymer containing the F polymer and polymer (P) as a matrix resin.

[0075] The laminates containing the polymer layer formed from the composition and the prepregs containing the F polymer and V polymer formed from the composition are useful as antenna parts, printed circuit boards, aircraft parts, automobile parts, sporting goods, food industry products, heat dissipation parts, etc. Specific examples include electric wire coating materials (aircraft electric wires, rectangular wires, FFC (Flexible Flat Cable), etc.), enameled wire coating materials used in motors of electric vehicles, etc., power generation coating materials, electrical insulating tapes, insulating tapes for oil drilling, oil transport hoses, hydrogen tanks, materials for printed circuit boards, separation membranes (microfiltration membranes, ultrafiltration membranes, reverse osmosis membranes, ion exchange membranes, dialysis membranes, gas separation membranes, etc.), electrode binders (for lithium secondary batteries, fuel cells, etc.), carrier films for fuel cells, tape substrate films for semiconductor manufacturing processes (dicing tape, pickup tape, etc.), release films for semiconductor molding, liquid crystal antennas, reflectors, transmission lines, COF (Chip on Fibre), etc. base films for film, electrostatic chucks for semiconductor manufacturing processes, electrostatic chucks for display manufacturing processes, copy rolls, furniture, automobile dashboards, covers for home appliances, etc., sliding parts (load bearings, yaw bearings, sliding shafts, valves, bearings, bushings, seals, thrust washers, wear rings, pistons, slide switches, gears, cams, belt conveyors, food transport belts, etc.), tension ropes, wear pads, wear strips, tube lamps, test sockets, wafer guides, wear parts for centrifugal pumps, chemical and water supply pumps, tools (shovels, files, saws, etc.), boilers, hoppers, pipes, ovens, baking molds, chutes, racket strings, dies, toilets, container coating materials, heat dissipation substrates for mounting power devices, heat dissipation materials for wireless communication devices, transistors, thyristors, rectifiers, transformers, power MOS They are useful as FETs, CPUs, heat dissipation fins, metal heat sinks, blades for wind turbines, wind power generation equipment, aircraft, etc., housings for personal computers and displays, electronic device materials, interior and exterior parts of automobiles, sealing materials for processing machines and vacuum ovens that perform heat treatment under low oxygen conditions, plasma processing equipment, etc., heat dissipation parts in processing units for sputtering and various dry etching equipment, etc., and electromagnetic wave shields.

[0076] The above-mentioned laminates and prepregs are also useful as electronic substrate materials such as flexible printed wiring boards and rigid printed wiring boards, protective films and heat dissipation substrates, particularly heat dissipation substrates for automobiles.

[0077] The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto. 1. Preparation of each component [F polymer] F particle 1: A polymer containing 97.9 mol % of TFE units, 0.1 mol % of NAH units, and 2.0 mol % of PPVE units, in this order, and having a carbonyl group-containing group with a main chain carbon number of 1×10 ６ Tetrafluoroethylene polymer particles (melting temperature: 300°C) with 1000 particles per particle (D50: 2.0 μm, specific surface area: 7 m ２ / g)

[0078] [Polymer (P)] V Polymer 1: A polymer having a nitrogen-containing heterocyclic structure and an etheric oxygen atom in the main chain and a group having a vinyl group or a vinylene group, represented by the following formula (number average molecular weight: 3,200):

[0079]

[0080] S Polymer 1: A copolymer of ethylene, styrene, and divinylbenzene obtained by the metallocene-catalyzed polymerization method described in JP 2009-161743 A, which is a styrene-based polymer having 2.8 vinyl groups per molecule and a number-average molecular weight of 36,000. The content of styrene-based polymers having more than two vinyl groups in the styrene-based polymer is 50% by mass or more. S Polymer 2: A copolymer of divinylbenzene, ethylvinylbenzene, and styrene obtained in cyclohexane using n-butyllithium as a polymerization catalyst, which is a functional group-modified styrene-based copolymer having 2.4 vinyl groups per molecule and a number-average molecular weight of 4,500, and which has been further modified at the active species end with 3-glycidoxypropyltrimethoxysilane. The content of styrene-based polymers having more than two vinyl groups in the styrene-based polymer is 50% by mass or more.

[0081] [Other polymers] Styrenic polymer 1: A copolymer of ethylene, styrene and divinylbenzene obtained by changing the amount of divinylbenzene used in the polymerization of S polymer 1, which has 10.6 vinyl groups per molecule and a number average molecular weight of 40,000.

[0082] 2. Liquid Composition Production Examples [Example 1-1] F Particles 1 and toluene as a non-aqueous dispersion medium were added to a pot, zirconia balls were added, and the pot was rolled at 150 rpm for 1 hour to disperse the F Particles 1. Dispersion 1, which contained 45% by mass of F Particles 1, was obtained. A varnish solution prepared by mixing V Polymer 1, bismaleimide (number average molecular weight 1500), and toluene, Dispersion 1, and dicumyl peroxide were added to a container and stirred to obtain non-aqueous liquid Composition 1-1 containing F Particles 1 (20 parts by mass), V Polymer 1 (50 parts by mass), bismaleimide (50 parts by mass), and toluene (100 parts by mass). The dicumyl peroxide used was equivalent to 1% by mass relative to the total amount of V Polymer 1, bismaleimide, and F Particles 1. In Liquid Composition 1-1, the content of F Particles 1 relative to V Polymer 1 was 0.4 in mass ratio, the viscosity of Liquid Composition 1-1 was 6000 mPa·s, and no foaming or aggregation of F Particles 1 was observed.

[0083] Example 1-2 A dispersion containing 45% by mass of F particles 1 was obtained in the same manner as in the preparation of Dispersion 1 in Example 1-1, except that a nonionic surfactant (Ftergent F710L, manufactured by Neos Corporation) was further used in an amount equivalent to 10% by mass relative to F particles 1. A nonaqueous liquid composition 1-2 containing F particles 1 (20 parts by mass), V polymer 1 (50 parts by mass), bismaleimide (50 parts by mass), dicumyl peroxide (1% by mass relative to the total amount of V polymer 1, bismaleimide, and F particles 1), and toluene (100 parts by mass) was obtained in the same manner as in Example 1-1, except that Dispersion 1-1 was replaced with this dispersion. The viscosity of Liquid Composition 1-2 was 4000 mPa s, and no foaming or aggregation of F particles 1 was observed.

[0084] Example 1-3 F Particles 1, V Polymer 1, bismaleimide (number average molecular weight 1500), dicumyl peroxide, and toluene were placed in a pot, and zirconia balls were added. The pot was then rolled at 150 rpm for 1 hour to obtain Liquid Composition 1-3 containing F Particles 1 (20 parts by mass), V Polymer 1 (50 parts by mass), bismaleimide (50 parts by mass), dicumyl peroxide (1% by mass relative to the total amount of V Polymer 1, bismaleimide, and F Particles 1), and toluene (100 parts by mass). In Liquid Composition 1-3, the content of F Particles 1 relative to V Polymer 1 was 0.4 by mass. The viscosity of Liquid Composition 1-3 was greater than 10,000 mPa·s, and foaming and aggregation of F Particles 1 were observed.

[0085] [Example 1-4] F Particles 1, V Polymer 1, bismaleimide (number average molecular weight 1500), dicumyl peroxide, and toluene were placed in a pot, and zirconia balls were added. The pot was then rolled at 150 rpm for 1 hour to obtain Liquid Composition 1-4, which contained F Particles 1 (12 parts by mass), V Polymer 1 (50 parts by mass), bismaleimide (50 parts by mass), dicumyl peroxide (1% by mass relative to the total amount of V Polymer 1, bismaleimide, and F Particles 1), and toluene (100 parts by mass). In Liquid Composition 1-4, the content of F Particles 1 relative to V Polymer 1 was 0.24 by mass. The viscosity of Liquid Composition 1-4 was 4000 mPa s, and no foaming or aggregation of F Particles 1 was observed.

[0086] Example 2-1 A varnish solution prepared by mixing S polymer 1, a silane coupling agent ("BM-503", Shin-Etsu Chemical Co., Ltd.), and toluene was added to a container, and dispersion 1 and dicumyl peroxide were added and stirred to obtain liquid composition 2-1 containing F particles 1 (20 parts by mass), S polymer 1 (50 parts by mass), a silane coupling agent (2.5 parts by mass), and toluene (100 parts by mass). In liquid composition 2-1, the content of F particles 1 relative to S polymer 1 was 0.4 by mass. Note that dicumyl peroxide was used in an amount equivalent to 1% by mass relative to the total amount of S polymer 1, bismaleimide, and F particles 1. The viscosity of liquid composition 2-1 was 4000 mPa s, and no foaming or aggregation of F particles 1 was observed, indicating excellent fluidity.

[0087] Example 2-2 A liquid composition 2-2 containing F particles 1 (20 parts by mass), S polymer 2 (50 parts by mass), a silane coupling agent (2.5 parts by mass), and toluene (100 parts by mass) was obtained in the same manner as in Example 2-1, except that S polymer 2 was used instead of S polymer 1. In liquid composition 2-2, the content of F particles 1 relative to S polymer 1 was 0.4 in terms of mass ratio. The viscosity of liquid composition 2-2 was 6000 mPa s, and no foaming or aggregation of F particles 1 was observed, indicating excellent fluidity.

[0088] Example 2-3 Liquid composition 2-3 containing F particles 1 (20 parts by mass), styrene-based polymer 1 (50 parts by mass), silane coupling agent (2.5 parts by mass), and toluene (100 parts by mass) was obtained in the same manner as in Example 2-1, except that styrene-based polymer 1 was used instead of S polymer 1. In liquid composition 2-3, the content of F particles 1 relative to S polymer 1 was 0.4 in terms of mass ratio. The viscosity of liquid composition 2-3 was 11,000 mPa s, and fluidity was reduced.

[0089] 3. Production Examples and Evaluation of Prepregs and Laminates Prepregs and laminates were produced using each of liquid compositions 1-1, 1-2, 1-4, 2-1, 2-2, and 2-3, and the formed polymer layers were evaluated. 3-1. Production of Prepregs and Laminates Glass cloth (Toyobo NE Glass, #1027) was immersed in each liquid composition for 2 minutes, then removed and dried at 100°C for 5 minutes and then at 160°C for 10 minutes to produce prepreg 1-1 from liquid composition 1-1, prepreg 1-2 from liquid composition 1-2, prepreg 1-4 from liquid composition 1-4, prepreg 2-1 from liquid composition 2-1, prepreg 2-2 from liquid composition 2-2, and prepreg 2-3 from liquid composition 2-3. Electrolytic copper foil (Mitsui Mining & Smelting Co., Ltd., electrolytic copper foil "SI-VSP-AM3R", thickness 18 μm) was placed on both sides of each prepreg, and hot pressed under vacuum to obtain a copper clad laminate.

[0090] 3-2. Evaluation of Properties The prepregs and copper-clad laminates were evaluated as follows. <Water Resistance> The water absorption of the prepregs was measured according to the method of JIS K 7209:2000A. Specifically, test specimens (10 cm x 10 cm) prepared from each prepreg were dried at 50°C for 24 hours and cooled in a desiccator. The mass of the test specimen at this point was recorded as the mass of the test specimen before immersion. Next, the test specimen was immersed in pure water at 23°C for 24 hours. The test specimen was removed from the pure water, the surface moisture was quickly wiped off, and the mass measured within 1 minute was recorded as the mass of the test specimen after immersion. The rate of change in mass of the test piece before and after immersion was taken as the water absorption rate of the prepreg, and the water resistance was evaluated according to the following criteria. As a result, prepreg 1-2 and prepreg 2-1 had the most excellent water resistance, prepreg 1-1 and prepreg 2-2 were next excellent, and prepreg 1-4 and prepreg 2-3 had poor water resistance.

[0091] <Dust shedding> A 5 ​​cm x 7 cm test piece was cut out from each prepreg and bent 180° toward the long side and the short side. Dust shedding was evaluated according to the following criteria. As a result, the test piece obtained from prepreg 2-1 and the test piece obtained from prepreg 2-2 had a lower amount of dust shedding than the test piece obtained from prepreg 2-3.

[0092] <Interlayer Adhesion> The 180° peel strength between the copper foil and prepreg in the copper clad laminate was measured in accordance with JIS C6471:1995 to evaluate the interlayer adhesion. As a result, no significant difference in peel strength was confirmed between the copper clad laminates obtained from Prepreg 1-1, Prepreg 1-2, and Prepreg 1-4. On the other hand, in the copper clad laminates obtained from Prepreg 2-1, Prepreg 2-2, and Prepreg 2-3, the peel strength of the copper clad laminates obtained from Prepreg 2-1 and Prepreg 2-2 was higher than the peel strength of the copper clad laminate obtained from Prepreg 2-3.

[0093] <Electrical Properties> The dielectric loss tangent of each copper-clad laminate was measured by the SPDR method at a frequency of 10 GHz in an environment within the range of 23°C ± 2°C and 50 ± 5% RH. As a result, the dielectric loss tangent of the copper-clad laminates obtained from Prepreg 1-1 and Prepreg 1-2 was lower than that of the copper-clad laminate obtained from Prepreg 1-4. Furthermore, the dielectric loss tangent of the copper-clad laminates obtained from Prepreg 2-1 and Prepreg 2-2 was lower than that of the copper-clad laminate obtained from Prepreg 2-3.

[0094] The polymer layer obtained from the liquid composition of the present invention and a laminate having the polymer layer highly exhibit the physical properties of the F polymer, have excellent adhesion to the substrate layer, and are excellent in water resistance, and can be effectively used in applications such as printed wiring boards. The entire contents of the specifications, claims, and abstracts of Japanese Patent Application Nos. 2023-210961 and 2023-210962, filed on December 14, 2024, are hereby incorporated by reference as the disclosure of the specification of the present invention.

Claims

1. A liquid composition comprising particles of a tetrafluoroethylene-based polymer, a polymer (P) having a vinyl group or a vinylene group, and a non-aqueous dispersion medium, wherein the polymer (P) is a polymer having a nitrogen-containing heterocyclic structure and an etheric oxygen atom in the main chain, or a styrene-based polymer having more than 2 and not more than 10 vinyl groups or vinylene groups in one molecule, wherein the content of the particles of the tetrafluoroethylene-based polymer relative to the content of the polymer (P) is greater than 0.33 by mass, and the viscosity is 10,000 mPa or less.

2. The liquid composition according to claim 1, wherein the polymer (P) is a polymer having a nitrogen-containing heterocyclic structure and an etheric oxygen atom in the main chain.

3. The liquid composition according to claim 1, wherein the tetrafluoroethylene polymer comprises a tetrafluoroethylene polymer having a carbonyl group-containing group and a melting temperature of 260° C. or higher.

4. The liquid composition according to claim 1, wherein the content of the tetrafluoroethylene-based polymer particles is more than 15 mass %.

5. The liquid composition according to claim 1, wherein the polymer further has at least one aromatic hydrocarbon ring structure or alicyclic hydrocarbon structure in the main chain.

6. The liquid composition according to claim 1, wherein the non-aqueous dispersion medium is a hydrocarbon, a ketone, an amide or an ester.

7. A method for producing a laminate, comprising: applying the liquid composition according to any one of claims 2 to 6 to a surface of a base layer to form a coating layer made of the liquid composition on the surface of the base layer; and heating the base layer having the coating layer thereon to obtain a laminate having the tetrafluoroethylene-based polymer and a polymer layer containing the polymer on the surface of the base layer.

8. A method for producing a prepreg, comprising impregnating a reinforcing fiber substrate with the liquid composition according to any one of claims 2 to 6 and disposing the same on the substrate.

9. The liquid composition according to claim 1, wherein the polymer (P) is a styrene-based polymer having more than 2 and not more than 10 vinyl groups or vinylene groups in one molecule.

10. The liquid composition according to claim 9, wherein the tetrafluoroethylene polymer comprises a tetrafluoroethylene polymer having a carbonyl group-containing group and a melting temperature of 260° C. or higher.

11. The liquid composition according to claim 9, wherein the content of the tetrafluoroethylene polymer particles is 10% by mass or more.

12. The liquid composition of claim 9, wherein the styrenic polymer contains units based on divinyl aromatic compounds and units based on monovinyl aromatic compounds.

13. The liquid composition according to claim 9, wherein the non-aqueous dispersion medium is a hydrocarbon, a ketone, an amide or an ester.

14. A method for producing a laminate, comprising: applying the liquid composition according to any one of claims 9 to 13 to a surface of a base layer to form a coating layer made of the liquid composition on the surface of the base layer; and heating the base layer having the coating layer thereon to obtain a laminate having a polymer layer containing the tetrafluoroethylene-based polymer and the styrene-based polymer on the surface of the base layer.

15. A method for producing a prepreg, comprising impregnating a reinforcing fiber substrate with the liquid composition according to any one of claims 9 to 13 and disposing the same on the substrate.

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