Aqueous dispersion and method for producing laminate using aqueous dispersion

Abstract

To provide an aqueous composition comprising a tetrafluoroethylene-based polymer that achieves excellent heat resistance and electrical characteristics (low coefficient of linear expansion, low dielectric constant, low dielectric loss tangent, and low transmission loss), allows formation of a molded article with superior uniformity in film thickness and composition and excellent laser processability, provides excellent handling properties, and ensures superior redispersibility after long-term storage.SOLUTION: An aqueous composition comprises particles of a tetrafluoroethylene-based polymer, a polyamic acid, a water-soluble polyol, and water, the content of the tetrafluoroethylene-based polymer particles being 30 mass% or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an aqueous dispersion containing particles of a tetrafluoroethylene-based polymer, and a method for producing a laminate using the aqueous dispersion. [Background technology]

[0002] In recent years, in order to cope with the increasing speed and frequency of communication devices, tetrafluoroethylene-based polymers, which have low dielectric constants and low dielectric loss tangents, have been attracting attention as insulating layer materials for printed circuit boards of communication devices. Dispersions containing tetrafluoroethylene-based polymer particles are known as materials for forming insulating layers containing such polymers. Generally, aqueous dispersions containing tetrafluoroethylene-based polymer particles are highly versatile in terms of the equipment required for their use and have a high degree of selectivity for substrates to be coated, etc. However, their liquid properties are often insufficient, and improvements to the liquid properties have been studied. Patent Document 1 discloses an aqueous composition containing tetrafluoroethylene-based polymer particles and an aqueous polyimide precursor, which is said to be applicable to copper-clad laminates and the like. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-020488 Summary of the Invention [Problem to be solved by the invention]

[0004] Tetrafluoroethylene-based polymer particles have low dispersibility in water. The present inventors have found that if the content of tetrafluoroethylene-based polymer particles in the aqueous composition of Patent Document 1 is increased or the content ratio of tetrafluoroethylene-based polymer particles to the aqueous polyimide precursor is increased in order to further develop the physical properties of the tetrafluoroethylene-based polymer, the liquid physical properties are reduced, and in particular, redispersibility after long-term storage is significantly reduced. In other words, there is a problem that compositional irregularities are likely to occur in the liquid over time, and the film thickness and composition of molded products such as polymer layers formed from the liquid are likely to be non-uniform.

[0005] The present inventors have found that a composition containing a tetrafluoroethylene-based polymer, a polyamic acid, a specific component, and water is easy to handle even when the content of tetrafluoroethylene-based polymer particles is increased, and has excellent redispersibility after long-term storage. Furthermore, they have also found that a molded product such as a polymer layer formed from such a composition has excellent physical properties, such as heat resistance and electrical properties (low linear expansion coefficient, low dielectric constant, low dielectric tangent, and low transmission loss) based on the tetrafluoroethylene-based polymer, and also has excellent uniformity in film thickness and composition within the molded product, and is excellent in laser processability, leading to the present invention. An object of the present invention is to provide an aqueous composition that has excellent physical properties such as heat resistance and electrical properties (low linear expansion coefficient, low dielectric constant, low dielectric dissipation factor, and low transmission loss), can be used to form molded articles that have excellent uniformity in film thickness and composition and are excellent in laser processability, and has excellent handleability and redispersibility after long-term storage. [Means for solving the problem]

[0006] The present invention has the following aspects. [1] An aqueous composition comprising particles of a tetrafluoroethylene-based polymer, a polyamic acid, a water-soluble polyol, and water, wherein the content of the particles of the tetrafluoroethylene-based polymer is 30% by mass or more. [2] The aqueous composition according to [1], wherein the tetrafluoroethylene-based polymer is a heat-fusible tetrafluoroethylene-based polymer containing an oxygen-containing polar group. [3] The aqueous composition according to [1] or [2], wherein the average particle size of the tetrafluoroethylene polymer particles is 1 μm or more and less than 10 μm. [4] The aqueous composition according to any one of [1] to [3], wherein the polyamic acid is water-soluble. [5] The aqueous composition according to [4], wherein the polyamic acid is a reaction product of a tetracarboxylic acid or a tetracarboxylic acid anhydride with a diamine having a solubility in water at 25°C of 50 g / L or more. [6] The aqueous composition according to [5], wherein the diamine having a solubility of 50 g / L or more in water at 25°C is dimer diamine. [7] The aqueous composition according to any one of [1] to [6], wherein the water-soluble polyol is a polymer selected from the group consisting of vinyl alcohol polymers and cellulose ethers. [8] The aqueous composition of any one of [1] to [6], wherein the water-soluble polyol is a polyoxyalkylene-modified dimethylsiloxane having a hydroxyl group and a polyoxyalkylene structure as a hydrophilic moiety and a polydimethylsiloxane structure as a hydrophobic moiety. [9] The aqueous composition of any one of [1] to [6], wherein the water-soluble polyol is a polymer selected from the group consisting of vinyl alcohol polymers and cellulose ethers, and a polyoxyalkylene-modified dimethylsiloxane having a hydroxyl group and a polyoxyalkylene structure as a hydrophilic moiety and a polydimethylsiloxane structure as a hydrophobic moiety.

[10] The aqueous composition of any one of [1] to [9], wherein the content of the tetrafluoroethylene-based polymer particles is more than 80 mass % based on the total amount of the tetrafluoroethylene-based polymer particles and the polyamic acid.

[11] The aqueous composition of any one of [1] to

[10] , wherein the content of the water-soluble polyol is 1 to 15 mass % relative to the particles of the tetrafluoroethylene-based polymer.

[12] The aqueous composition according to any one of [1] to

[11] , having a viscosity of 10 to 10,000 mPa·s.

[13] A method for producing a laminate, comprising placing an aqueous composition according to any one of [1] to

[12] on a surface of a substrate and heating the composition to form a polymer layer containing the tetrafluoroethylene-based polymer, and obtaining a laminate having, in this order, a substrate layer made of the substrate and the polymer layer. [Effects of the Invention]

[0007] According to the present invention, there is provided an aqueous composition that is easy to handle and redispersible after long-term storage. From such an aqueous composition, a molded article such as a coating film (polymer layer) can be formed, which has excellent physical properties based on the tetrafluoroethylene polymer, such as heat resistance and electrical properties (low linear expansion coefficient, low dielectric constant, low dielectric dissipation factor, and low transmission loss), and which has excellent uniformity in film thickness and composition within the molded article and is excellent in laser processability. DETAILED DESCRIPTION OF THE INVENTION

[0008] The following terms have the following meanings: "Average particle size (D50)" is the volume-based cumulative 50% diameter of particles or fillers determined by laser diffraction / scattering. In other words, particle size distribution is measured by laser diffraction / scattering, and a cumulative curve is calculated with the total volume of the particle group as 100%. The "average particle size (D50)" is the particle size at the point on the cumulative curve where the cumulative volume is 50%. The D50 of particles or fillers can be determined by dispersing the particles in water and analyzing them by a laser diffraction / scattering method using a laser diffraction / scattering particle size distribution analyzer (LA-920 measuring instrument, manufactured by Horiba, Ltd.). The "average particle size (D90)" is the volume-based cumulative 90% diameter of particles, which is determined in the same manner as D50. The specific surface area of ​​particles or fillers is a value calculated by measuring particles by gas adsorption (constant volume method) BET multipoint method, and is determined using NOVA4200e (manufactured by Quantachrome Instruments). The "melting temperature" is the temperature corresponding to the maximum value of the melting peak of a polymer as measured by differential scanning calorimetry (DSC). The "glass transition temperature (Tg)" is a value measured by analyzing a polymer using the dynamic mechanical analysis (DMA) method. The "viscosity" is determined by measuring the dispersion 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 measurements is used. The "thixotropy ratio" is a value calculated by dividing the viscosity η1 of the dispersion measured at a rotation speed of 30 rpm by the viscosity η2 measured at a rotation speed of 60 rpm. Each viscosity measurement is repeated three times, and the average value of the three measurements is used. The "surface tension" of a solvent or solution is a value measured by the Wilhelmy method at 25°C using a surface tensiometer. The term "unit" in a polymer refers to an atomic group based on a monomer formed by polymerization of the monomer. The unit may be a unit formed directly by a polymerization reaction, or may be a unit in which a portion of the unit is converted into a different structure by processing the polymer. Hereinafter, a unit based on monomer a will also be referred to simply as a "monomer a unit."

[0009] The aqueous composition of the present invention (hereinafter also referred to as "the composition") contains particles (hereinafter also referred to as "F particles") of a tetrafluoroethylene-based polymer (hereinafter also referred to as "F polymer"), polyamic acid, a water-soluble polyol, and water, and the content of F particles is 30 mass% or more. This composition is easy to handle and redisperse after long-term storage. As a result, molded articles such as coating films (polymer layers) formed from this composition have excellent uniformity in film thickness and composition within the molded article, are excellent in laser processability, and have excellent physical properties such as heat resistance and electrical properties (low linear expansion coefficient, low dielectric constant, low dielectric loss tangent, and low transmission loss) based on the tetrafluoroethylene-based polymer. The reason why the present composition is easy to handle and easy to redisperse after long-term storage is not entirely clear, but is thought to be as follows.

[0010] In aqueous dispersions such as those described in Patent Document 1, interactions occur between the F particles and the aqueous polyimide precursor (polyamic acid), and aggregation is thought to be suppressed. However, this state is likely to change over time and depending on the content of F particles in the aqueous dispersion and the ratio of F particles to the aqueous polyimide precursor. Furthermore, when the content of F particles is high, the fluidity of the F particles is likely to be hindered when forming a fired product (processed product) of the F particles, resulting in poor packing of the F particles and a deterioration in the physical properties of the molded product. In this composition, the water-soluble polyol interacts with both the F particles and the polyamic acid, presumably maintaining a gentle interaction between the F particles and the polyamic acid. Therefore, this composition is easy to handle, and aggregation is suppressed even when the F particle content is high, making it easy to redisperse after long-term storage. Therefore, when forming a coating film after application, the composition is excellent in film thickness and composition uniformity, and laser processability, and is thought to have improved physical properties in molded products such as polymer layers formed from this composition. This mechanism of action tends to be more pronounced when the F particles constituting the present composition are particles made of a heat-fusible F polymer having an oxygen-containing polar group.

[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 polymer F may be either heat-fusible or non-heat-fusible. Here, a heat-fusible polymer means a polymer that has a temperature at which the melt flow rate is 1 to 1000 g / 10 min under a load of 49 N. The melting temperature of the heat-meltable F polymer is preferably 180° C. or higher, more preferably 200° C. or higher. The melting temperature of the F polymer is preferably 325° C. or lower, more preferably 320° C. or lower. In this case, molded articles such as coating films (polymer layers) formed from the composition tend to have excellent heat resistance. 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 more, more preferably 72 to 76% by mass.

[0012] The F polymer is preferably polytetrafluoroethylene (PTFE), a polymer containing TFE units and units based on ethylene (ETFE), a polymer containing TFE units and units based on propylene, a polymer containing TFE units and units based on perfluoro(alkyl vinyl ether) (PAVE) (PAVE units) (PFA), or a polymer containing TFE units and units based on hexafluoropropylene (FEP), with PFA and FEP being more preferred, and PFA being even more preferred. These polymers may further contain units based on other comonomers. Examples of PTFE include low molecular weight PTFE and modified PTFE. PAVE is preferably CF2=CFOCF3, CF2=CFOCF2CF3, or CF2=CFOCF2CF2CF3 (hereinafter also referred to as "PPVE"), and PPVE is more preferred.

[0013] The F polymer preferably has an oxygen-containing polar group, more preferably has a hydroxyl-containing group or a carbonyl-containing group, and even more preferably has a carbonyl-containing group. In this case, the composition tends to have excellent handleability and redispersibility after long-term storage. Furthermore, molded articles such as coating films (polymer layers) formed from the composition tend to have excellent physical properties such as heat resistance and electrical properties (low linear expansion coefficient, low dielectric constant, low dielectric dissipation factor, and low transmission loss), as well as excellent film thickness and composition uniformity and laser processability. The hydroxyl group-containing group is preferably a group containing an alcoholic hydroxyl group, more preferably -CF2CH2OH and -C(CF3)2OH. The carbonyl group-containing group is preferably a carboxyl group, an alkoxycarbonyl group, an amide group, an isocyanate group, a carbamate group (-OC(O)NH), an acid anhydride residue (-C(O)OC(O)-), an imide residue (-C(O)NHC(O)-, etc.) or a carbonate group (-OC(O)O-), and more preferably an acid anhydride residue. 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 based on the polymer composition or the method described in WO 2020 / 145133.

[0014] 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.

[0015] The F polymer is preferably a polymer having a carbonyl group-containing group containing TFE units and PAVE units, more preferably a polymer containing TFE units, PAVE units, and units based on a monomer having a carbonyl group-containing group, in which the total units contain 90 to 99 mol%, 0.99 to 9.97 mol%, and 0.01 to 3 mol%, respectively, in that order. Specific examples of such F polymers include the polymers described in WO 2018 / 16644. The monomer having a carbonyl group-containing group is preferably itaconic anhydride, citraconic anhydride, or 5-norbornene-2,3-dicarboxylic anhydride (hereinafter also referred to as "NAH"), and more preferably NAH.

[0016] In the present invention, the D50 of the F particles is preferably 1 μm or more and 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 1.0 μm or more, more preferably 1.5 μm or more. The D50 of the F particles is preferably 6 μm or less, more preferably 5 μm or less. Furthermore, the D90 of the F particles is preferably 8 μm or less, more preferably 6 μm or less. When the D90 of the F particles is within the above range, the above-mentioned mechanism of action is more easily realized, and the present composition having a small number of coarse particles is more likely to be obtained. The specific surface area of ​​F particles is 1 to 25 m 2 / g, and 6 to 15m 2 In this case, the composition is easy to handle.

[0017] The F particles are particles containing an F polymer, and preferably consist of an F polymer. The F particles are more preferably particles of a heat-fusible F polymer having an oxygen-containing polar group and a melting temperature of 260° C. In this case, the above-mentioned mechanism of action is more effectively exerted, and aggregation of the F particles is more easily suppressed. The F particles may contain a resin or an inorganic compound other than the F polymer, may form a core-shell structure with an F polymer as the core and a resin other than the F polymer or an inorganic compound as the shell, or may form a core-shell structure with an F polymer as the shell and a resin other than the F polymer or an inorganic compound as the core. Here, examples of resins other than F polymer include aromatic polyester, polyamideimide, polyimide, and maleimide, and examples of inorganic compounds include silica and boron nitride. One type of F particle may be used, or two or more types may be used.

[0018] The polyamic acid constituting the present composition is a polyimide precursor obtained by reacting a tetracarboxylic acid or a tetracarboxylic acid anhydride with a diamine, and is preferably a polyimide precursor obtained by reacting a tetracarboxylic acid dianhydride with a diamine.

[0019] Examples of the tetracarboxylic dianhydride include bis(2,3- or 3,4-dicarboxyphenyl)methane dianhydride, 1,1-bis(2,3- or 3,4-dicarboxyphenyl)ethane dianhydride, 2,2-bis(2,3- or 3,4-dicarboxyphenyl)propane dianhydride, bis(2,3- or 3,4-dicarboxyphenyl)sulfone dianhydride, 2,2-bis(3,4-dicarboxyphenyl)tetrafluoropropane dianhydride, 1,2,3,4-cyclobutane tetracarboxylic dianhydride, and 1,2,3,4-cyclopentane tetracarboxylic dianhydride. Water, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic-1,2:4,5-dianhydride, dicyclohexyl-3,3',4,4'-tetracarboxylic dianhydride, bicyclo[2.2.2]oct-7-ene-2,3;5,6-tetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,3,3',4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, benzophenone tetracarboxylic acid dicarboxylic acid dianhydride, 4,4'-oxydiphthalic acid dianhydride, diphenylsulfonetetracarboxylic acid dianhydride, 4,4'-bis(2,3-dicarboxyphenoxy)diphenylmethane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, p-phenylenebis(trimellitic acid monoester acid anhydride), ethylene glycol bistrimellitic acid anhydride, 1,4-phenylenebis(trimellitic acid monoester) dianhydride, 2,3',3,4'-diphenylethertetracarboxylic acid dianhydride, 3,3',4,4'- Diphenyl ether tetracarboxylic dianhydride, bis(2,3-dicarboxyphenyl) ether dianhydride, 1,2,7,8-, 1,2,6,7- or 1,2,9,10-phenanthrene tetracarboxylic dianhydride, 2,3,6,7-anthracene tetracarboxylic dianhydride, 1,2,5,6-, 1,4,5,8- or 2,3,6,7-naphthalene tetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6-tetracarboxylic dianhydride, 2,6- or 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7-tetrachloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, p-terphenyltetracarboxylic dianhydride, m-terphenyltetracarboxylic dianhydride, 2,3,8,9-, 3,4,9,10-, 4,5,10,11- or 5,6,11,12-perylenetetracarboxylic dianhydride, pyrazine-2,3,5,6-tetracarboxylic dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 3,3'-(hexafluoroisopropylidene)diphthalic anhydride, 5,5'-[2, Examples of such an anhydride include 2,2-trifluoro-1-[3-(trifluoromethyl)phenyl]ethylidene]diphthalic anhydride, 5,5'-[2,2,3,3,3-pentafluoro-1-(trifluoromethyl)propylidene]diphthalic anhydride, 1H-difuro[3,4-b:3',4'-i]xanthene-1,3,7,9(11H)-tetrone, 5,5'-oxybis[4,6,7-trifluoro-pyromellitic anhydride], 3,6-bis(trifluoromethyl)pyromellitic dianhydride, 4-(trifluoromethyl)pyromellitic dianhydride, 1,4-difluoropyromellitic dianhydride, and 1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrafluorobenzene dianhydride. These may be used alone or in combination of two or more.

[0020] Examples of diamines include 1,3-propanediamine, trans- or cis-1,4-diaminocyclohexane, 1,6-hexamethylenediamine, 1,10-decamethylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, polyoxypropylenediamine, bis(p-aminocyclohexyl)methane, paraphenylenediamine, metaphenylenediamine, 1,3-bis(3-aminophenoxy)benzene, 2,4-bis(β-amino-t-butyl)toluene, m-xylene-2,5-diamine, and the like. amine, p-xylene-2,5-diamine, m- or p-xylylenediamine, 4,4'-oxydianiline, 3,4'-oxydianiline, 4,4'-diaminodiphenylmethane, 2,4-toluenediamine, 3,3'-dihydroxy-4,4'-diaminobiphenyl, bis(4-amino-3-carboxyphenyl)methane, 3,3'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-n-propyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, bis[4-(3-amino phenoxy)biphenyl, bis[1-(3-aminophenoxy)]biphenyl, 2,2-bis-[4-(3-aminophenoxy)phenyl]propane, bis[4-(3-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]methane, bis[4-(3-aminophenoxy)phenyl]ether, bis[4-(3-aminophenoxy)]benzophenone, 3,3'-diaminodiphenylethane, 3,3'-dimethoxybenzidine, 4,4'-methylene-di-o-toluidine, 4,4'-methylene-di-2,6-xylylene aniline, 4,4'-methylene-2,6-diethylaniline, 4,4'-[1,4-phenylenebis(1-methylethylidene)]bisaniline, 4,4'-[1,3-phenylenebis(1-methylethylidene)]bisaniline, bis(p-β-amino-t-butylphenyl)ether, bis(p-β-methyl-δ-aminopentyl)benzene, p-bis(2-methyl-4-aminopentyl)benzene, p-bis(1,1-dimethyl-5-aminopentyl)benzene, 1,3-bis[2-(4-aminophenyl)-2-propyl]benzene, 1,5- or 2,6-Diaminonaphthalene, 4-aminophenyl-4'-aminobenzoate, 2,6- or 2,5-diaminopyridine, 2,5-diamino-1,3,4-oxadiazole, 2'-methoxy-4,4'-diaminobenzanilide, 4,4'-diaminobenzanilide, piperazine, 6-amino-2-(4-aminophenoxy)benzoxazole, 9,9-bis[4-(3-aminophenoxy)phenyl]fluorene, 3,3''-diamino-p-terphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 2,3,5,6-tetrafluoro-1,4-diaminobenzene, 2,4,5,6-tetrafluoro-1 ,3-diaminobenzene, 2,3,5,6-tetrafluoro-1,4-benzene (dimethanamine), 2,2'-difluoro-(1,1'-biphenyl)-4,4'-diamine, 2,2',6,6'-tetrafluoro-(1,1'-biphenyl)-4,4'-diamine, 4,4'-diaminooctafluorobiphenyl, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis-[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis-[4-(3-aminophenoxy)phenyl]hexafluoropropane, 4,4'-oxybis(2,3,5,6-tetrafluoroaniline). These may be used alone or in combination of two or more.

[0021] Alternatively, dimer diamine may be used as the diamine. Dimer diamine refers to a diamine in which the two terminal carboxylic acid groups (—COOH) of a dimer acid are substituted with primary aminomethyl groups (—CH—NH) or amino groups (—NH). Here, dimer acids are dimerized fatty acids obtained by intermolecular polymerization (Diels-Alder reaction) of natural fatty acids such as soybean oil fatty acids, tall oil fatty acids, and rapeseed oil fatty acids, and unsaturated fatty acids having 11 to 22 carbon atoms, such as oleic acid, linolenic acid, and erucic acid, which are obtained by refining these fatty acids. In this specification, hydrogenated dimer acids, in which the remaining double bonds are further hydrogenated to reduce the degree of unsaturation, are also included in the dimer acids.

[0022] The polyamic acid is preferably water-soluble. From this viewpoint, the polyamic acid is preferably a reaction product of a tetracarboxylic dianhydride and a diamine having a solubility of 50 g / L or more in water at 25°C, which can impart water solubility and facilitate the above-mentioned mechanism of action. Examples of diamines with a solubility of 50 g / L or more in water at 25°C include paraphenylenediamine (120 g / L), metaphenylenediamine (77 g / L), 2,4-toluenediamine (62 g / L), bis(4-amino-3-carboxyphenyl)methane (200 g / L), trans- or cis-1,4-diaminocyclohexane (1000 g / L), 1,6-hexamethylenediamine (1000 g / L), 1,10-decamethylenediamine (1000 g / L), 1,3-bis(aminomethyl)cyclohexane (1000 g / L), 1,4-bis(aminomethyl)cyclohexane (999 g / L), and the above-mentioned dimer diamines. The values ​​in parentheses indicate the solubility in water at 25°C. Among these, dimer diamines are more preferred. When two or more diamines are used in combination, the above-mentioned diamine having high solubility in water can be combined with another diamine so that the solubility of the entire diamine component in water at 25°C is 50 g / L or more. The solubility in water at 25°C was calculated using Advanced Chemistry Development (ACD / Labs) Software V11.02 (Copyright 1994-2011 ACD / Labs) under various conditions that can be searched using SciFinder (registered trademark), and the value at pH 7 was shown.

[0023] The polyamic acid can be produced by reacting the above-mentioned tetracarboxylic acid (tetracarboxylic dianhydride) with the above-mentioned diamine in water or an alcoholic solvent at a molar ratio of tetracarboxylic acid to diamine in the range of 0.90 to 1.10, preferably 0.95 to 1.05.

[0024] The water-soluble polyol contained in the present composition includes a polymer selected from the group consisting of vinyl alcohol polymers and cellulose ethers, and a polyoxyalkylene-modified dimethylsiloxane having a hydroxyl group and a polyoxyalkylene structure as the hydrophilic moiety and a polydimethylsiloxane structure as the hydrophobic moiety. These may be used alone or in combination of two or more. As the water-soluble polyol, it is preferable to use the above-mentioned polymer or the above-mentioned polyoxyalkylene-modified dimethylsiloxane. It is more preferable to use both the polymer and the polyoxyalkylene-modified dimethylsiloxane as the water-soluble polyol, since this makes it easier to realize the above-mentioned mechanism of action.

[0025] Examples of vinyl alcohol polymers include polyvinyl alcohol, partially acetylated or partially acetalized polyvinyl alcohol, and copolymers of vinyl alcohol, vinyl butyral, and vinyl acetate. Specific examples of vinyl alcohol polymers include the "S-LEC (registered trademark) B" series, the "S-LEC (registered trademark) K (KS)" series, and the "S-LEC (registered trademark) SV" series (all manufactured by Sekisui Chemical Co., Ltd.), and the "Mobital (registered trademark)" series (manufactured by Kuraray Co., Ltd.). Examples of cellulose ethers include carboxyalkyl celluloses such as carboxymethyl cellulose, hydroxyalkyl celluloses such as hydroxymethyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose, and hydroxyalkyl alkyl celluloses such as hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, hydroxyethyl ethyl cellulose, and hydroxyethyl ethyl methyl cellulose. Specific examples of cellulose ethers include the "Sunrose (registered trademark)" series (manufactured by Nippon Paper Industries Co., Ltd.), the "Metolose (registered trademark)" series (manufactured by Shin-Etsu Chemical Co., Ltd.), and "HEC CF Grade" (manufactured by Sumitomo Seika Chemicals Co., Ltd.).

[0026] Polyoxyalkylene-modified dimethylsiloxane, which has a hydroxyl group and a polyoxyalkylene structure as the hydrophilic portion and a polydimethylsiloxane structure as the hydrophobic portion, has a polydimethylsiloxane unit (-(CH3)2SiO 2 / 2 The polyoxyalkylene-modified polydimethylsiloxane may have a dimethylsiloxane unit in the main chain, or may have a polydimethylsiloxane unit in both the main chain and the side chain. The polyoxyalkylene-modified polydimethylsiloxane is preferably a polyoxyalkylene-modified polydimethylsiloxane containing a dimethylsiloxane unit in the main chain and an oxyalkylene group in the side chain, or a polyoxyalkylene-modified polydimethylsiloxane containing a dimethylsiloxane unit in the main chain and an oxyalkylene group at the end of the main chain. The oxyalkylene groups contained in the polyoxyalkylene-modified dimethylsiloxane may consist of only one type of oxyalkylene group, or may consist of two or more types of oxyalkylene groups. In the latter case, the different types of oxyalkylene groups may be linked randomly or in blocks. Examples of such polyoxyalkylene-modified dimethylsiloxanes include "BYK-347," "BYK-349," "BYK-378," "BYK-3450," "BYK-3451," "BYK-3455," and "BYK-3456" (manufactured by BYK Japan), and "KF-6011" and "KF-6043" (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0027] The composition may further contain a nonionic surfactant, such as a glycol-based surfactant, an acetylene-based surfactant, a silicone-based surfactant other than the polyoxyalkylene-modified dimethylsiloxane, or a fluorine-based surfactant.

[0028] The composition may contain other dispersion media as long as the effects of the present invention are not impaired. It is preferable that such other dispersion media be miscible with water. Examples of other dispersion media include amides such as 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; and ketones such as acetone and methyl ethyl ketone.

[0029] The present composition may further contain an inorganic filler, in which case molded articles such as coating films (polymer layers) formed from the present composition tend to have excellent electrical properties and low linear expansion. The shape of the inorganic filler may be any of spherical, needle-like (fibrous), and plate-like, and specifically may be spherical, scale-like, layer-like, leaf-like, apricot-like, columnar, cockscomb-like, equiaxed, leaf-like, micaceous, block-like, flat, wedge-like, rosette-like, net-like, and prismatic. Examples of inorganic fillers 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 filler may be used, or two or more types may be used in combination. The D50 of the inorganic filler is preferably 0.1 to 50 μm. The surface of the inorganic filler may be surface-treated with a silane coupling agent. When the present composition contains an inorganic filler, the content of the inorganic filler in the present composition is preferably 1 to 25 mass %.

[0030] The present composition may further contain another resin different from the F polymer and the water-soluble polyol described above. Such another resin may be contained in the present composition as non-hollow particles, or may be dissolved or dispersed in a liquid dispersion medium such as water constituting the present composition or other dispersion mediums contained as necessary (hereinafter, water, other dispersion mediums, etc., are also collectively referred to as "liquid dispersion mediums"). Examples of other resins include polyester resins such as liquid crystalline aromatic polyesters, epoxy resins, polyamide resins, polyimide resins, polyamideimide resins, maleimide resins, urethane resins, polyphenylene ether resins, polyphenylene oxide resins, and polyphenylene sulfide resins. Among these, at least one aromatic imide polymer selected from the group consisting of aromatic polyimides and aromatic polyamideimides is more preferred. The aromatic imide polymer is preferably contained in the composition as a varnish dissolved in a liquid dispersion medium. When the present composition further contains another resin, the content of the other resin relative to the F particles is preferably 1 to 25% by mass.

[0031] The present composition may further contain additives such as a thixotropic agent, a viscosity modifier, an antifoaming agent, a plasticizer, a weather resistance 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.

[0032] The composition can be obtained by mixing F particles, polyamic acid, water-soluble polyol, water, and, if necessary, the other dispersion mediums, inorganic fillers, other resins, additives, etc., as described above. The composition may be obtained by mixing the F particles, polyamic acid, water-soluble polyol, and water all at once, or by mixing them separately and sequentially, or by preparing a masterbatch of these components in advance and then mixing the remaining components with this masterbatch. The order of mixing is not particularly limited, and the mixing method may be either all at once or divided into multiple batches.

[0033] For example, it is preferable to pre-disperse the F particles in a portion of the water, then add and mix the polyamic acid and water-soluble polyol in that order, and then add the resulting mixture to the remaining water to obtain the present composition, as this makes it easier to improve the redispersibility even when the F particle content is high. The polyamic acid and the water-soluble polyol may be added as they are or as an aqueous solution, or may be added in a state of being dispersed or dissolved in another dispersion medium. Furthermore, when the above-mentioned other dispersion media, inorganic fillers, other resins, additives, etc. are further mixed as needed, they may be mixed when the F particles and water are mixed, or they may be mixed when the mixture is added to water.

[0034] 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.

[0035] The content of F particles in the composition is preferably 30% by mass or more, more preferably 40% by mass or more, and is preferably 75% by mass or less, more preferably 60% by mass or less.

[0036] In the present composition, from the viewpoints of improving the handleability of the composition, improving redispersibility after long-term storage, and further exhibiting the physical properties of the F polymer, the content of the F particles relative to the total amount of the F particles and the polyamic acid is preferably more than 80% by mass, more preferably more than 90% by mass, and is preferably 99% by mass or less relative to the total amount of the F particles and the polyamic acid.

[0037] The content of the water-soluble polyol in the present composition is preferably in the range of 1 to 15% by mass, more preferably 3 to 10% by mass, relative to the F particles in the present composition, from the viewpoint of more easily realizing the above-mentioned mechanism of action.

[0038] The water content in the composition is preferably 25% by mass or more, more preferably 40% by mass or more. The water content is preferably less than 70% by mass, more preferably 65% ​​by mass or less. The water content in the composition is preferably 60 to 180% by mass relative to the F particle content.

[0039] The viscosity of the composition is preferably 10 to 10,000 mPa·s. The viscosity of the composition is preferably 15 mPa·s or higher, more preferably 25 mPa·s or higher. The viscosity of the composition is preferably 5,000 mPa·s or lower, more preferably 1,000 mPa·s or lower. In this case, the composition has excellent coatability and is easily formed into molded articles such as coating films (polymer layers) 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 molded articles formed from the composition, and the composition is easily made to have excellent laser processability. The thixotropy ratio of the present composition is preferably 1.0 to 2.5, in which case the present composition has excellent coatability and uniformity and is likely to produce denser molded articles.

[0040] The dielectric constant of a molded article formed from this composition 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 molded article 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 molded article is preferably 1 W / m K or more, more preferably 3 W / m K or more.

[0041] This composition can be subjected to a molding method such as extrusion into a sheet to form a molded product such as a sheet containing the F polymer. The extruded sheet may be further cast by press molding, calendar molding, etc. The sheet is preferably further heated to remove the liquid dispersion medium and bake the F polymer.

[0042] The thickness of the sheet formed from the present composition is preferably 1 to 1000 μm. The suitable ranges of the dielectric constant, dielectric loss tangent, and thermal conductivity of the sheet are the same as those of the molded product described above. Note that the thermal conductivity of the sheet means the thermal conductivity in the in-plane direction of the sheet. The linear expansion coefficient of the sheet is preferably 100 ppm / °C or less, more preferably 80 ppm / °C or less. The lower limit of the linear expansion coefficient of the sheet 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.

[0043] Such a sheet can be laminated on a substrate to form a laminate. Examples of methods for producing a laminate include extrusion molding of the composition onto the substrate, and thermocompression bonding of the sheet and the substrate. Examples of the 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 crystalline polyester, and tetrafluoroethylene-based polymers; prepreg substrates (precursors of fiber-reinforced resin substrates), ceramic substrates such as silicon carbide, aluminum nitride, and silicon nitride; and glass substrates. The metal foil is preferably copper foil, more preferably rolled copper foil with no front or back, or electrolytic copper foil with a front and back, and even more preferably rolled copper foil. Rolled copper foil has a small surface roughness, so transmission loss can be reduced even when the metal clad laminate is processed into a printed wiring board. It is preferable to use rolled copper foil after immersing it in a hydrocarbon organic solvent to remove the rolling oil.

[0044] The shape of the substrate may be flat, curved, or uneven, and may be any of foil, plate, film, and fiber. The ten-point average roughness of the surface of the substrate is preferably 0.01 to 0.05 μm, which improves adhesion to the sheet containing the F polymer, making it easier to obtain a printed circuit board with excellent transmission characteristics. The surface of the substrate 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 a functional group such as 3-aminopropyltriethoxysilane, vinyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-isocyanatopropyltriethoxysilane. The peel strength between the sheet and the substrate is preferably 10 to 100 N / cm.

[0045] Furthermore, by placing this composition on the surface of a substrate and heating it to form a polymer layer containing an F polymer (hereinafter also referred to as an "F layer"), a laminate having, in this order, a substrate layer made of the substrate and an F layer can be obtained. The F layer is preferably formed by disposing the composition on the surface of a substrate, heating it to remove the liquid dispersion medium, and further heating it to bake the F polymer. By separating the substrate from such a laminate, a sheet containing the F polymer can be obtained. Examples of the substrate include the same substrates as those that can be laminated with the above-mentioned sheet, and the preferred embodiments thereof are also the same.

[0046] The composition can be applied by coating, droplet discharging, or immersion, preferably by roll coating, knife coating, bar coating, die coating, or spraying. The heating for removing the liquid dispersion medium is preferably carried out at 100 to 200°C for 0.1 to 30 minutes. The liquid dispersion medium does not need to be completely removed during heating; it is sufficient to remove it to the extent that the layer formed by packing of the F particles can maintain a self-supporting film. Furthermore, during heating, air may be blown onto the surface to aid in the removal of the liquid dispersion medium by air drying.

[0047] The heating for baking the F polymer is preferably carried out at a temperature equal to or higher than the melting point of the F polymer, more preferably at 360 to 400° C. for 0.1 to 30 minutes. Heating devices for each heating method include ovens and ventilation drying furnaces. 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 rays, etc.). The heating may be carried out under normal pressure or under reduced pressure. The atmosphere during each heating step may be either an air atmosphere or an inert gas atmosphere (helium gas, neon gas, argon gas, nitrogen gas, etc.).

[0048] The F layer is formed through the steps of disposing the composition and heating. These steps may be performed once each, or may be repeated two or more times. For example, the composition may be disposed on the surface of a substrate and heated to form an F layer, and then the composition may be disposed on the surface of the F layer and heated to form a second F layer. Alternatively, the composition may be disposed on the surface of a substrate and heated to remove the liquid dispersion medium, and then the composition may be disposed on the surface of the substrate and heated to form an F layer. The composition may be disposed on only one surface of the substrate, or on both surfaces of the substrate. In the former case, a laminate having a substrate layer and an F layer on one surface of the substrate layer is obtained, while in the latter case, a laminate having a substrate layer and an F layer on both surfaces of the substrate layer is obtained. The thickness of the F layer varies depending on the application of the laminate, but is preferably in the range of 1 to 1000 μm.

[0049] Specific examples of suitable laminates include a metal clad laminate having a metal foil and an F layer on at least one surface of the metal foil, and a multilayer film having a polyimide film and an F layer on both surfaces of the polyimide film. The thickness of the metal foil is preferably less than 20 μm, more preferably 2 to 15 μm, from the viewpoint of being able to exhibit sufficient functionality in the application of the metal clad laminate. The preferred ranges for the thickness, dielectric constant, dielectric dissipation factor, thermal conductivity, linear expansion coefficient, and peel strength between the F layer and the substrate layer are the same as the preferred ranges for the thickness, dielectric constant, dielectric dissipation factor, thermal conductivity, linear expansion coefficient, and peel strength between the sheet and the substrate in the sheet formed from the composition described above.

[0050] The composition is useful as a material for imparting insulating properties, heat resistance, corrosion resistance, chemical resistance, water resistance, impact resistance, and thermal conductivity. Specifically, the composition can be used in printed wiring boards, thermal interface materials, power module substrates, coils used in power devices such as motors, automotive engines, heat exchangers, vials, syringes, ampoules, medical wires, secondary batteries such as lithium ion batteries, primary batteries such as lithium batteries, radical batteries, solar cells, fuel cells, lithium ion capacitors, hybrid capacitors, capacitors (aluminum electrolytic capacitors, tantalum electrolytic capacitors, etc.), electrochromic elements, electrochemical switching elements, electrode binders, electrode separators, and electrodes (positive electrodes, negative electrodes). The composition is also useful as an adhesive for bonding parts. Specifically, the composition can be used to bond ceramic parts, metal parts, electronic parts such as IC chips, resistors, and capacitors on substrates for semiconductor elements and module parts, circuit boards and heat sinks, and LED chips to substrates.

[0051] Molded articles such as sheets and laminates formed from the present composition are useful as antenna parts, printed circuit boards, aircraft parts, automobile parts, sporting goods, food industry products, heat dissipation parts, etc. Specifically, these include electric wire coating materials (aircraft electric wires, etc.), enameled wire coating materials used in motors for electric vehicles, etc., electrical insulating tape, insulating tape 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.), copy rolls, furniture, automobile dashboards, covers for home appliances, etc., sliding components (load bearings, yaw bearings, sliding shafts, valves, bearings, bushings, seals, thrust washers, wear rings, etc.), and many other applications. useful in applications such as: pistons, slide switches, gears, cams, conveyor belts, food transport belts, 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 coatings, heat dissipation substrates for mounting power devices, heat dissipation components for wireless communication devices, transistors, thyristors, rectifiers, transformers, power MOS 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, heat dissipation components in processing units for sputtering and various dry etching equipment, and electromagnetic wave shielding.

[0052] Molded articles such as sheets and laminates formed from the present composition are useful as electronic substrate materials such as flexible printed wiring boards and rigid printed wiring boards, protective films and heat dissipating substrates. The metal clad laminate formed from the composition can be used as a flexible copper clad laminate or a rigid copper clad laminate for producing a printed circuit board. The printed circuit board can be produced, for example, by processing the metal foil in the metal clad laminate into a conductor circuit (patterned circuit) of a predetermined pattern by etching or the like, or by processing the metal clad laminate into a patterned circuit by electroplating (semi-additive process (SAP process), modified semi-additive process (MSAP process), etc.). In the manufacture 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 using the above powder dispersion. In the manufacture of a printed circuit board, a solder resist may be laminated on a pattern circuit, and the solder resist may be formed from the powder dispersion liquid. In the manufacture of printed circuit boards, a coverlay film may be laminated onto the pattern circuit. The metal clad laminate formed from the present composition is suitable for processing with a laser such as a UV-YAG laser, and allows via holes with good shapes to be easily formed, making it particularly suitable as a printed circuit board material.

[0053] The present composition and the method for producing a laminate having a polymer layer formed from the present composition have been described above, but the present invention is not limited to the configurations of the above-mentioned embodiments. For example, the present composition may have any other optional components added to the configurations of the above-mentioned embodiments, or may be replaced with any optional components that exhibit similar functions. Furthermore, the method for producing a laminate having a polymer layer formed from the present composition may have any other optional components added to the configurations of the above-mentioned embodiments, or may be replaced with any optional components that exhibit similar functions. [Example]

[0054] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. 1. Preparation of each ingredient [F Polymer] F particle 1: Contains 97.9 mol%, 0.1 mol%, and 2.0 mol% of TFE units, NAH units, and PPVE units, in that order, and has 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) F Particle 2: Particles (D50: 10.0 μm) made of a tetrafluoroethylene-based polymer (melting temperature: 300°C) containing 97.5 mol% TFE units and 2.5 mol% PPVE units, in that order, and having no oxygen-containing polar groups. F Particle 3: Particles made of non-thermal melt processable PTFE (D50: 0.3 μm)

[0055] [Polyamic acid] PAA1: Polyamic acid prepared from equimolar amounts of 3,3',4,4'-biphenyltetracarboxylic dianhydride and paraphenylenediamine (solubility in water at 25°C: 120 g / L) PAA2: Polyamic acid prepared from equimolar amounts of 3,3',4,4'-biphenyltetracarboxylic dianhydride and 4,4'-diaminodiphenyl ether (solubility in water at 25°C: 0.19 g / L)

[0056] [Water-soluble polyol] Polyol 1: Polyoxyalkylene-modified dimethylsiloxane (BYK-3450, manufactured by BYK Japan) having a hydroxyl group and a polyoxyalkylene structure as the hydrophilic portion and a polydimethylsiloxane structure as the hydrophobic portion. Polyol 2: Hydroxyethyl cellulose Polyol 3: Partially saponified ethylene-vinyl acetate copolymer [Surfactants] Surfactant 1: Octylphenol ethoxylate

[0057] 2. Example of production of aqueous composition [Example 1] F Particles 1, PAA1 solution, Polyol 1, and water were added to the pot, followed by the addition of zirconia balls. The pot was then rolled at 150 rpm for 1 hour to obtain Aqueous Composition 1 (viscosity: 100 mPa s) containing F Particles 1 (30.7 parts by mass), PAA1 (0.8 parts by mass), Polyol 1 (1.5 parts by mass), and water (67 parts by mass).

[0058] [Examples 2-8] Aqueous compositions 2 to 8 were obtained in the same manner as in Example 1, except that the types and amounts of F polymer particles, polyamic acid, water-soluble polyol and surfactant, and the amount of water used were changed as shown in Table 1.

[0059] [Table 1]

[0060] 4. Redispersibility of aqueous compositions Aqueous compositions 1 to 8 obtained in Examples 1 to 8 were stored in containers at 25°C for 90 days, and then visually inspected for the presence or absence of component settling. If component settling was observed, the composition was further stirred under shear, and the ease of redispersion was evaluated according to the following criteria. The results are shown in Table 1. [Evaluation criteria] A: No visible aggregates are observed in the composition even after storage. B: Agglomerates are visible at the bottom of the container, but are easily redispersed. C: Aggregates were visually observed settling at the bottom of the container, and although they were redispersed, they tended to become viscous. D: Agglomerates are visible at the bottom of the container. Redispersion is difficult.

[0061] 5. Preparation of laminates and evaluation of polymer layers Double-sided copper-clad laminates were produced using each of the aqueous compositions 1 to 4, and their UV laser processability and transmission loss were evaluated. 5-1. Example of manufacturing double-sided copper clad laminate Using a roll-to-roll process, each aqueous composition was coated onto one surface of a substrate (polyimide film (PI Advanced Materials, "FG-100": 25 μm thick) using a small-diameter gravure reverse method to form a coating layer. The film was then passed through a ventilated drying oven (oven temperature: 150°C) for 3 minutes to remove the water and form a dry film. Similarly, each dispersion was coated onto the other surface of the substrate to form a coating layer, which was then dried to form a dry film. The substrate with the dry films on both sides was then passed through a far-infrared oven (oven temperature: 300°C near the inlet and outlet, and 360°C near the center) for 5 minutes to melt and sinter the F particles, resulting in a laminate with polymer layers (25 μm thick) on both sides of the substrate. Furthermore, copper foil (electrolytic copper foil CF-T49A-DS-HD2-12, Fukuda Metal Foil & Powder Co., Ltd.) was placed on both sides of the obtained laminate, and pressed under vacuum at 340°C for 20 minutes to obtain a double-sided copper-clad laminate.

[0062] 5-2. UV laser processability The double-sided copper-clad laminate obtained above was irradiated with a 355 nm UV-YAG laser in a circular pattern with a diameter of 100 μm using a laser processing machine. This resulted in the formation of circular through-holes in the double-sided copper-clad laminate. The laser output was 1.2 W, the laser focal diameter was 25 μm, the number of circular movements was 20, and the oscillation frequency was 40 kHz. The double-sided copper-clad laminate was then cut out from the through-holes and hardened with a thermosetting epoxy resin. The cut pieces were then polished until the cross-sections of the through-holes were exposed. The cross-sections of the through-holes were then observed under a microscope and evaluated according to the following criteria. The results are shown in Table 2. [Evaluation criteria] A: No irregularities were observed in the cross section of the through-hole, deterioration of the polymer layer and polyimide film due to UV was highly suppressed, and no peeling was observed between the polymer layer and polyimide film. B: Although irregularities were observed in the cross section of the through-hole, deterioration of the polymer layer and polyimide film due to UV was suppressed, and no peeling was observed between the polymer layer and polyimide film. C: Irregularities were observed in the cross section of the through-hole, the polymer layer and polyimide film were partially deteriorated by UV, and delamination of less than 5 μm was observed between the polymer layer and the polyimide film. D: Irregularities were observed in the cross section of the through-hole, the polymer layer and polyimide film were partially deteriorated by UV, and delamination of 5 μm or more was observed between the polymer layer and the polyimide film.

[0063] 5-3.Dielectric tangent For each laminate, the dielectric loss tangent of the polymer layer of the laminate was measured at 10 GHz using a Fabry-Perot resonator and a vector network analyzer (manufactured by Keycom), and the transmission loss was evaluated according to the following criteria. The results are shown in Table 2. [Evaluation criteria] A: 0.0015 or less B: More than 0.0015 and less than 0.0030 C: over 0.0030

[0064] [Table 2] [Industrial Applicability]

[0065] The aqueous composition of the present invention has excellent handleability and redispersibility. Furthermore, the physical properties of the F polymer are highly expressed, and molded articles such as coating films (polymer layers) that are excellent in UV processability, heat resistance, electrical properties, etc. can be formed. Therefore, metal clad laminates containing such polymer layers can be processed and used for antenna parts, printed circuit boards, aircraft parts, automobile parts, etc.

Claims

1. 1. An aqueous composition comprising particles of a tetrafluoroethylene-based polymer, a polyamic acid, a water-soluble polyol, and water, wherein the content of the particles of the tetrafluoroethylene-based polymer is 30% by mass or more.

2. 2. The aqueous composition of claim 1, wherein the tetrafluoroethylene-based polymer is a heat-fusible tetrafluoroethylene-based polymer containing oxygen-containing polar groups.

3. 2. The aqueous composition according to claim 1, wherein the average particle size of the tetrafluoroethylene polymer particles is 1 μm or more and less than 10 μm.

4. The water-based composition of claim 1 , wherein the polyamic acid is water-soluble.

5. 5. The aqueous composition according to claim 4, wherein the polyamic acid is a reaction product of a tetracarboxylic acid or a tetracarboxylic acid anhydride with a diamine having a solubility in water at 25°C of 50 g / L or more.

6. 6. The aqueous composition according to claim 5, wherein the diamine having a solubility in water at 25°C of 50 g / L or more is dimer diamine.

7. 2. The aqueous composition of claim 1, wherein the water-soluble polyol is a polymer selected from the group consisting of vinyl alcohol polymers and cellulose ethers.

8. 2. The aqueous composition according to claim 1, wherein the water-soluble polyol is a polyoxyalkylene-modified dimethylsiloxane having a hydroxyl group and a polyoxyalkylene structure as a hydrophilic moiety and a polydimethylsiloxane structure as a hydrophobic moiety.

9. 2. The aqueous composition according to claim 1, wherein the water-soluble polyol is a polymer selected from the group consisting of vinyl alcohol polymers and cellulose ethers, and a polyoxyalkylene-modified dimethylsiloxane having a hydroxyl group and a polyoxyalkylene structure as a hydrophilic moiety and a polydimethylsiloxane structure as a hydrophobic moiety.

10. 2. The aqueous composition according to claim 1, wherein the content of the tetrafluoroethylene-based polymer particles is more than 80 mass% based on the total amount of the tetrafluoroethylene-based polymer particles and the polyamic acid.

11. 2. The aqueous composition according to claim 1, wherein the content of the water-soluble polyol is 1 to 15% by mass relative to the particles of the tetrafluoroethylene-based polymer.

12. 2. The aqueous composition according to claim 1, having a viscosity of 10 to 10,000 mPa·s.

13. A method for producing a laminate, comprising: placing the aqueous composition according to any one of claims 1 to 12 on a surface of a substrate and heating the composition to form a polymer layer containing the tetrafluoroethylene-based polymer; and obtaining a laminate having, in this order, a substrate layer constituted by the substrate and the polymer layer.

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