WO2024075609A1 - 水性分散液 - Google Patents
水性分散液 Download PDFInfo
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- WO2024075609A1 WO2024075609A1 PCT/JP2023/035169 JP2023035169W WO2024075609A1 WO 2024075609 A1 WO2024075609 A1 WO 2024075609A1 JP 2023035169 W JP2023035169 W JP 2023035169W WO 2024075609 A1 WO2024075609 A1 WO 2024075609A1
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- polymer
- aqueous dispersion
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L1/00—Compositions of cellulose, modified cellulose or cellulose derivatives
- C08L1/08—Cellulose derivatives
- C08L1/26—Cellulose ethers
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L27/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers
- C08L27/02—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment
- C08L27/12—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment containing fluorine atoms
- C08L27/18—Homopolymers or copolymers or tetrafluoroethene
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L29/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal or ketal radical; Compositions of hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Compositions of derivatives of such polymers
- C08L29/02—Homopolymers or copolymers of unsaturated alcohols
- C08L29/04—Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
Definitions
- the present invention relates to an aqueous dispersion containing particles of a tetrafluoroethylene-based polymer.
- aqueous dispersions have high versatility in the equipment required for their use and high selectivity for substrates to be coated, and improvement of the liquid properties by various additives has been studied.
- Patent Document 1 proposes an aqueous dispersion in which the pH at 25° C. and the solids concentration of the tetrafluoroethylene-based polymer are within a predetermined range, and the metal ion content is less than 100 ppm relative to the entire aqueous dispersion.
- Patent Document 2 proposes a dispersion containing polyvinylidene fluoride particles, a specific nonionic surfactant, a specific polymer surfactant, and a dispersion medium, and in which the contents of sodium ions, potassium ions, and ammonium ions are each equal to or less than a predetermined amount.
- Tetrafluoroethylene-based polymer particles have low water dispersibility, and their aqueous dispersions tend to foam, so that the handling properties of the aqueous dispersions, such as fluidity, are not sufficient.
- a viscosity regulator such as a water-soluble polymer
- the viscosity and thixotropy of the aqueous dispersion can be improved, but there is still room for improvement in terms of suppressing foaming.
- cations contained in the aqueous dispersion have been recognized as components that should be removed as much as possible, as they cause the coloration and decomposition of tetrafluoroethylene-based polymers and cause equipment contamination, as shown in Patent Document 1 or Patent Document 2 and other documents.
- an aqueous dispersion containing a tetrafluoroethylene-based polymer, a specific water-soluble polymer, and water, and in which the concentrations of alkali metal ions and alkaline earth metal ions in the liquid are controlled within a specific range, has excellent dispersion stability, is suppressed from foaming, and is easy to handle.
- a molded product such as a polymer layer formed from such a dispersion has excellent physical properties such as heat resistance and electrical properties (low linear expansion coefficient, low dielectric constant and low dielectric tangent) based on the tetrafluoroethylene-based polymer, and has excellent surface appearance, and have arrived at the present invention.
- An object of the present invention is to provide an aqueous dispersion containing a tetrafluoroethylene polymer, which is excellent in physical properties such as heat resistance and electrical properties (low linear expansion coefficient, low dielectric constant and low dielectric tangent), can form a molded product having excellent surface appearance, and has excellent dispersion stability and handleability.
- An aqueous dispersion comprising particles of a tetrafluoroethylene-based polymer, a water-soluble polymer having at least one polar functional group selected from the group consisting of a vinyl alcohol-based polymer, an acrylic polymer, polyvinylpyrrolidone, polypyrrole, polythiophene, polyethylene oxide, polyethyleneimine, and cellulose ether, and water, wherein the concentration of at least one cation selected from the group consisting of alkali metal ions and alkaline earth metal ions is 0.1 to 1000 ppm.
- (6) The aqueous dispersion according to any one of (1) to (5), wherein the water-soluble polymer is a vinyl alcohol-based polymer.
- (7) The aqueous dispersion according to any one of (1) to (5), wherein the water-soluble polymer is a cellulose ether.
- a method for producing a laminate comprising placing the aqueous dispersion according to any one of (1) to (14) on a surface of a substrate and heating the surface to form a polymer layer containing the tetrafluoroethylene-based polymer, and obtaining a laminate having a substrate layer constituted by the substrate and the polymer layer in this order.
- the present invention provides an aqueous dispersion with excellent dispersion stability and ease of handling.
- a molded product such as a coating film (polymer layer) can be formed that has excellent physical properties based on the tetrafluoroethylene polymer, such as heat resistance and electrical properties (low linear expansion coefficient, low dielectric constant, and low dielectric tangent), and has excellent surface appearance.
- the "average particle size (D50)" is the volume-based cumulative 50% diameter of a particle or filler determined by a laser diffraction/scattering method. That is, the particle size distribution is measured by a laser diffraction/scattering method, a cumulative curve is calculated with the total volume of the particle group as 100%, and 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 a particle or filler can be determined by dispersing the particles in water and analyzing them by a laser diffraction/scattering method using a laser diffraction/scattering type 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, which is determined in the same manner as D50.
- the specific surface area of a particle or filler is a value calculated by measuring the particle by a gas adsorption (constant volume method) BET multipoint method, and is determined using a gas adsorption type pore distribution measuring instrument (product name NOVA4200e, manufactured by Quantachrome Instruments).
- Melting temperature is the temperature corresponding to the maximum of the melting peak of a polymer as measured by differential scanning calorimetry (DSC).
- DSC differential scanning calorimetry
- glass transition temperature (Tg)” is a value measured by analyzing a polymer using a 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 measured values is calculated.
- the "thixotropy ratio” is a value calculated by dividing the viscosity ⁇ 1 of the dispersion measured at a rotation speed of 30 rpm by the viscosity ⁇ 2 measured at a rotation speed of 60 rpm. Each viscosity measurement is repeated three times, and the average value of the three measured values 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 "degree of substitution” of cellulose ether is also called the degree of etherification, and represents the number (average value) of hydroxyl groups substituted with alkoxyl groups among the three hydroxyl groups on the glucose ring of cellulose. Theoretically, the degree of substitution can have a value between 0 and 3, and generally, the higher the substituent, the more hydrophilic the substance is.
- the degree of substitution is calculated by converting the value measured by the substitution degree analysis method for hydroxypropyl methylcellulose described in the 18th revised Japanese Pharmacopoeia.
- the "cation concentration" of the aqueous dispersion is a value calculated from the content of cations contained in a measurement sample obtained by ashing the dried aqueous dispersion at 1000°C for 4 minutes, which is determined by frameless atomic absorption spectrometry, and the mass of the aqueous dispersion.
- a "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 a polymerization reaction, or may be a unit in which a part of the unit is converted into a different structure by processing the polymer.
- a unit based on monomer a is also simply referred to as a "monomer a unit.”
- the aqueous dispersion of the present invention contains particles (hereinafter also referred to as "F particles") of a tetrafluoroethylene-based polymer (hereinafter also referred to as "F polymer”), a water-soluble polymer having at least one polar functional group selected from the group consisting of a vinyl alcohol-based polymer, an acrylic polymer, polyvinylpyrrolidone, polypyrrole, polythiophene, polyethylene oxide, polyethyleneimine, and cellulose ether (hereinafter also referred to as "water-soluble polymer”), and water, and has a concentration of at least one cation selected from the group consisting of alkali metal ions and alkaline earth metal ions (hereinafter also referred to as "cation concentration”) of 0.1 to 1000 ppm.
- F particles a tetrafluoroethylene-based polymer
- F polymer a water-soluble polymer having at least one polar functional group selected from the group consisting of a vinyl alcohol-
- This dispersion is excellent in dispersion stability and handling, and a molded product such as a coating film (polymer layer) formed from this dispersion is excellent in physical properties such as heat resistance and electrical properties (low linear expansion coefficient, low dielectric constant and low dielectric tangent) based on the tetrafluoroethylene polymer, and is excellent in surface appearance.
- excellent surface appearance includes both excellent surface smoothness such as “less surface roughness” and excellent appearance observed visually or with an analytical instrument such as "no streaks, cracks, defects, etc. on the surface.”
- the viscosity of the aqueous dispersion can be increased, and the liquid properties such as thixotropy (thixotropy) can be improved. It also acts as a binder for the F particles when forming a processed product such as a coating film from the aqueous dispersion.
- the aqueous dispersion tends to foam easily, making it difficult to handle, and the transparency of the molded product tends to decrease, making it difficult to select an appropriate water-soluble polymer.
- the cation concentration is controlled within a specific range of 0.1 to 1000 ppm.
- the concentration of at least one cation selected from the group consisting of alkali metal ions and alkaline earth metal ions is 0.1 to 1000 ppm.
- the cation concentration is preferably 0.2 ppm or more, more preferably 0.5 ppm or more, and even more preferably more than 1 ppm.
- the cation concentration is preferably 100 ppm or less, more preferably 10 ppm or less, and even more preferably 5 ppm or less. In this case, the above-mentioned mechanism of action is likely to be significantly exhibited.
- the binder function of the water-soluble polymer contained in the present dispersion is further enhanced, and when the present dispersion is placed on the surface of a substrate and heated to form a polymer layer containing an F polymer, powder falling of the F particles is suppressed, and the occurrence of defects and the like is easily prevented to a high degree. Furthermore, the hue of the obtained polymer layer is easily maintained better.
- the cation include alkali metal ions such as lithium ion, sodium ion, potassium ion, rubidium ion, and cesium ion, and alkaline earth metal ions such as beryllium ion, magnesium ion, calcium ion, strontium ion, and barium ion. Among these, it is preferable that the cation is at least one of sodium ion and potassium ion.
- the above-mentioned cations can be contained in the present dispersion due to their origin in each of the constituent components.
- the above-mentioned cations include cations derived from the F polymer.
- Such cations include cations derived from metal hydroxides such as sodium hydroxide and potassium hydroxide used as pH adjusters in the post-treatment step in the polymerization to obtain the F polymer.
- the above-mentioned cations include cations derived from water-soluble polymers.
- cellulose ether is obtained by a manufacturing method in which refined pulp is contacted with an alkaline solution such as sodium hydroxide or potassium hydroxide, and then an etherifying agent is applied to convert the hydroxyl group contained in the cellulose into an ether, so that the cations may be derived from the alkaline solution.
- the vinyl alcohol polymer may include cations derived from metal hydroxides such as sodium hydroxide or potassium hydroxide used as a saponifying agent in the saponification step after polymerization of vinyl ester.
- cations may be contained as minerals.
- the amount of cations derived from each component constituting the present dispersion may be controlled in advance.
- desalting treatments include a method of previously washing the F polymer with water to control its cation concentration, a method of previously washing a water-soluble polymer with a washing solution to control its cation concentration, and a method of previously controlling the cation concentration of the water used.
- the dispersion after preparation may be treated with an ion exchange resin to control and adjust the cation concentration within the above range.
- the F polymer in the present invention is a polymer containing units based on tetrafluoroethylene (hereinafter also referred to as "TFE") (hereinafter also referred to as “TFE units”).
- the F polymer may be either heat-fusible or non-heat-fusible.
- 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 F polymer, which is heat-fusible is preferably 180° C. or higher, and more preferably 200° C. or higher.
- the melting temperature of the F polymer is preferably 325° C. or lower, and more preferably 320° C. or lower.
- a molded product such as a coating film (polymer layer) formed from the present dispersion tends 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.
- F polymer is preferably polytetrafluoroethylene (PTFE), the polymer that comprises TFE unit and ethylene-based unit (ETFE), the polymer that comprises TFE unit and propylene-based unit, the polymer that comprises TFE unit and perfluoro(alkyl vinyl ether) (PAVE)-based unit (PAVE unit) (PFA), the polymer that comprises TFE unit and hexafluoropropylene-based unit (FEP), more preferably PFA and FEP, and even more preferably PFA.
- PTFE include low molecular weight PTFE and modified PTFE.
- the number average molecular weight of the low molecular weight PTFE is preferably 200,000 or less, more preferably 100,000 or less, and even more preferably 50,000 or less.
- the number average molecular weight of the PTFE is preferably 10,000 or more.
- the number average molecular weight is a value calculated based on the following formula (1).
- Mn 2.1 ⁇ 1010 ⁇ Hc ⁇ 5.16 (1)
- Mn represents the number average molecular weight of the low-molecular-weight PTFE
- ⁇ Hc represents the heat of crystallization (cal/g) of the low-molecular-weight PTFE measured by differential scanning calorimetry.
- PAVE is preferably CF 2 ⁇ CFOCF 3 , CF 2 ⁇ CFOCF 2 CF 3 or CF 2 ⁇ CFOCF 2 CF 2 CF 3 (hereinafter also referred to as “PPVE”), and more preferably PPVE.
- the F polymer preferably has an oxygen-containing polar group, more preferably has a hydroxyl group-containing group or a carbonyl group-containing group, and even more preferably has a carbonyl group-containing group.
- the dispersion liquid is more likely to exhibit the above-mentioned mechanism of action associated with controlling the cation concentration within the range specified in the present invention, and is excellent in dispersion stability and handling.
- the molded product such as a coating film (polymer layer) formed from the dispersion liquid is excellent in physical properties such as heat resistance, electrical properties (low linear expansion coefficient, low dielectric constant and low dielectric loss tangent), and its surface appearance.
- the hydroxyl-containing group is preferably a group containing an alcoholic hydroxyl group, more preferably --CF 2 CH 2 OH or --C(CF 3 ) 2 OH.
- 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 2 ), 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.
- the number of oxygen-containing polar groups in the F polymer is preferably 10 to 5000, more preferably 100 to 3000, per 1 ⁇ 10 6 carbon atoms in the main chain.
- 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.
- the oxygen-containing polar group may be contained in a unit based on a monomer in the F polymer, or may be contained in a terminal group of the main chain of the F polymer, with the former being preferred.
- Examples of the latter include F polymers having an oxygen-containing polar group as a terminal group derived from a polymerization initiator, a chain transfer agent, etc., and F polymers obtained by subjecting F polymers to plasma treatment or ionizing radiation treatment.
- the F polymer is preferably a polymer containing TFE units and PAVE units and units based on a monomer having a carbonyl group-containing group, more preferably a polymer containing TFE units, PAVE units and units based on a monomer having a carbonyl group-containing group, and more preferably a polymer containing these units in this order in an amount of 90 to 99 mol%, 0.99 to 9.97 mol%, and 0.01 to 3 mol% relative to the total units.
- 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.
- the D50 of the F particles is preferably 1 ⁇ m or more and less than 10 ⁇ m.
- 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 ⁇ m or more, and more preferably 1.5 ⁇ m or more.
- the D50 of the F particles is preferably 6 ⁇ m or less, and more preferably 5 ⁇ m or less.
- D90 of the F particles is preferably 8 ⁇ m or less, and more preferably 6 ⁇ m or less.
- the specific surface area of the F particles is preferably from 1 to 25 m 2 /g, and more preferably from 6 to 15 m 2 /g.
- 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 200 to 325° 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.
- examples of the resin other than the F polymer include aromatic polyester, polyamideimide, polyimide, and maleimide, and examples of the inorganic compound include silica and boron nitride.
- the F particles may be used alone or in combination of two or more kinds.
- the water-soluble polymer contained in the dispersion is at least one selected from the group consisting of vinyl alcohol polymers, acrylic polymers, polyvinylpyrrolidone, polypyrrole, polythiophene, polyethylene oxide, polyethyleneimine, and cellulose ether, and has a polar functional group.
- the term "water-soluble polymer” refers to a polymer having a solubility in water of 20 g/L or more.
- the polar functional group is preferably an ether bond, an ester bond, an amide bond, an imide bond, a thioether bond, a sulfide bond, a disulfide bond, a carbonyl group-containing group, a hydroxyl group-containing group, a thiol group, a sulfide group, a sulfonyl group, a sulfoxyl group, an amino group, or an amide group, more preferably a hydroxyl group-containing group, and even more preferably a nonionic hydroxyl group.
- the polar functional group may be present in either the main chain or the side chain of the polymer.
- polyvinylpyrrolidone, polypyrrole, polythiophene, polyethylene oxide, or polyethyleneimine further has a hydroxyl group, it is preferable that the hydroxyl group is present at the end of the main chain of the polymer.
- vinyl alcohol-based polymers examples include polyvinyl alcohol, polyvinyl acetate, partially acetylated or partially acetalized polyvinyl alcohol, and copolymers of vinyl alcohol, vinyl butyral, and vinyl acetate.
- Specific examples of vinyl alcohol-based 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.).
- acrylic polymer examples include polyacrylic acid, salts of polyacrylic acid such as sodium polyacrylate, sodium acrylic acid/maleic acid copolymer, and sodium acrylic acid/sulfonic acid monomer copolymer, polyacrylates such as methyl polyacrylate and ethyl polyacrylate, poly- ⁇ -haloacrylate, poly- ⁇ -cyanoacrylate, and polyacrylamide.
- the cellulose ethers include alkyl celluloses, carboxyalkyl celluloses, hydroxyalkyl celluloses, or hydroxyalkyl alkyl celluloses.
- Examples of the carboxyalkyl cellulose include carboxymethyl cellulose.
- Examples of the hydroxyalkyl cellulose include hydroxymethyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose.
- Examples of the hydroxyalkyl alkyl cellulose include hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, hydroxyethyl ethyl cellulose, hydroxyethyl ethyl methyl cellulose, etc. These may be used alone or in combination of two or more kinds. Among these, carboxyalkyl cellulose, hydroxyalkyl cellulose, or hydroxyalkyl alkyl cellulose is preferred, hydroxyalkyl cellulose is more preferred, and hydroxyethyl cellulose is even more preferred.
- the degree of substitution of the cellulose ether is preferably 1.4 or more, more preferably 1.9 or more, and even more preferably 2.1 or more.
- the degree of substitution of the cellulose ether is preferably 2.9 or less, and more preferably 2.7 or less.
- the weight average molecular weight of the cellulose ether is preferably 1,000 to 10,000.
- the weight average molecular weight can be measured, for example, by gel permeation chromatography (GPC) using a differential refractive index detector.
- GPC gel permeation chromatography
- 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.).
- the water-soluble polymer is preferably at least one selected from the group consisting of vinyl alcohol polymers and cellulose ethers.
- the weight average molecular weight of the water-soluble polymer is preferably 1000 or more, more preferably 10000 or more, further preferably 100000 or more, and particularly preferably 300000 or more.
- the weight average molecular weight of the water-soluble polymer is preferably 1000000 or less, more preferably 500000 or less.
- the present dispersion may further contain a viscosity regulator other than the above-mentioned water-soluble polymer, from the viewpoint of adjusting the viscosity and thixotropy ratio.
- the water-soluble polymer is preferably at least one selected from the group consisting of vinyl alcohol-based polymers and cellulose ethers.
- the weight-average molecular weight of the water-soluble polymer is preferably 1,000 or more, more preferably 10,000 or more, even more preferably 100,000 or more, and particularly preferably 300,000 or more.
- the weight-average molecular weight of the water-soluble polymer is preferably 1,000,000 or less, more preferably 500,000 or less.
- the present dispersion may further contain a viscosity regulator other than the above-mentioned water-soluble polymer, from the viewpoint of adjusting the viscosity and thixotropy ratio.
- the dispersion may further contain a nonionic surfactant.
- nonionic surfactants include glycol-based surfactants, acetylene-based surfactants, silicone-based surfactants, and fluorine-based surfactants.
- One type of nonionic surfactant may be used, or two or more types may be used.
- silicone-based surfactants are preferred, and polyoxyalkylene-modified dimethylsiloxanes having a polyoxyalkylene structure as the hydrophilic portion and a polydimethylsiloxane structure as the hydrophobic portion are more preferred.
- the polyoxyalkylene-modified dimethylsiloxane may have a polydimethylsiloxane unit (-( CH3 ) 2SiO2 /2- ) in the main chain, may have a polydimethylsiloxane unit in the side 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 a main chain terminal.
- the oxyalkylene group contained in the polyoxyalkylene-modified dimethylsiloxane may be composed of only one type of oxyalkylene group, or may be composed 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.
- the HLB value of the silicone surfactant is preferably 10 or more.
- silicone surfactants include "BYK-347”, “BYK-349”, “BYK-378”, “BYK-3450”, “BYK-3451”, “BYK-3455”, “BYK-3456” (manufactured by BYK Japan), "KF-6011", and “KF-6043” (manufactured by Shin-Etsu Chemical Co., Ltd.).
- the dispersion further contains a nonionic surfactant, preferably a silicone surfactant, the content 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 dispersion.
- a nonionic surfactant preferably a silicone surfactant
- the dispersion may further contain an alcohol having 1 to 6 carbon atoms.
- an alcohol having 1 to 6 carbon atoms is a compound that is liquid at atmospheric pressure and 25°C, and preferably has a boiling point of 160°C or less, more preferably a compound with a boiling point of 120°C or less.
- Examples of the alcohol having 1 to 6 carbon atoms include methanol (23 mN/m), ethanol (23 mN/m), 1-propanol (24 mN/m), 2-propanol (22 mN/m), 1-butanol (25 mN/m), 2-butanol (24 mN/m), isobutanol (23 mN/m), 1-methoxy-2-propanol (26 mN/m), 2-propoxy-ethanol (27 mN/m), 1-propoxy-2-propanol (25 mN/m), 2-ethoxyethanol (26 mN/m), ethylene glycol (48 mN/m), propylene glycol (25 mN/m), and glycerin (63 mN/m).
- the numerical values in parentheses indicate the surface tension of each alcohol. These may be used alone or in combination of two or more. When two or more types of the alcohols are used, they are preferably compatible with each other.
- the content is preferably 0.1% by mass or more, and more preferably 1% by mass or more, relative to the dispersion.
- the content of the alcohol having 1 to 6 carbon atoms is preferably 10% by mass or less, and more preferably 5% by mass or less.
- dispersion media may be used in this dispersion liquid as long as the effects of the present invention are not impaired. It is preferable that such other dispersion media are miscible with the above-mentioned alcohol and 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.
- 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
- the present dispersion may further contain an inorganic filler, in which case the formed product such as a coating film (polymer layer) formed from the present dispersion is likely to have excellent electrical properties and low linear expansion.
- the shape of the inorganic filler may be any of spherical, acicular (fibrous), and plate-like, and specifically may be spherical, scaly, lamellar, leaflet-like, apricot kernel-like, columnar, cockscomb-like, equiaxed, leaf-like, micaceous, block-like, flat, wedge-like, rosette-like, net-like, and prismatic.
- 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.
- the inorganic filler may be used alone or in combination of two or more kinds.
- the D50 of the inorganic filler is preferably 0.1 to 50 ⁇ m.
- the surface of the inorganic filler may be treated with a silane coupling agent.
- Suitable specific examples of the inorganic filler include silica fillers (Admafine (registered trademark) series (manufactured by Admatechs Co., Ltd.), SFP (registered trademark) series (manufactured by Denka Co., Ltd.), E-SPHERES series (manufactured by Taiheiyo Cement Corporation), etc.), zinc oxide fillers (FINEX (registered trademark) series (manufactured by Sakai Chemical Industry Co., Ltd.), etc.), titanium oxide fillers (Tipaque (registered trademark) series (manufactured by Ishihara Sangyo Kaisha, Ltd.), JMT (registered trademark) series (manufactured by Teika Co., Ltd.), etc.), talc fillers (SG series (manufactured by Nippon Talc Co., Ltd.), etc.), steatite fillers (BST series (manufactured by Nippon Talc Co., Ltd.
- the present dispersion may further contain another resin different from the F polymer.
- another resin may be contained in the present dispersion as non-hollow particles, or may be dissolved or dispersed in a liquid dispersion medium such as water constituting the present dispersion, or an alcohol having 1 to 6 carbon atoms or other dispersion medium contained as necessary (hereinafter, water, an alcohol having 1 to 6 carbon atoms, other dispersion medium, etc. are collectively referred to as "liquid dispersion medium").
- polyester resins such as liquid crystalline aromatic polyesters, polyimide resins, polyamideimide resins, epoxy resins, maleimide resins, urethane resins, polyphenylene ether resins, polyphenylene oxide resins, and polyphenylene sulfide resins.
- the other resin is preferably an aromatic polymer, more preferably at least one aromatic imide polymer selected from the group consisting of aromatic polyimide, aromatic polyamic acid, aromatic polyamideimide, and a precursor of aromatic polyamideimide.
- the aromatic polymer is preferably contained in the present dispersion as a varnish dissolved in a liquid dispersion medium.
- aromatic imide polymers include the "UPIA-AT” series (UBE), the “NEOPLIM (registered trademark)” series (Mitsubishi Gas Chemical Company, Inc.), the “SPIXELIA (registered trademark)” series (Somar), the “Q-PILON (registered trademark)” series (PI Technical Research Institute), the "WINGO” series (Wingo Technology Co., Ltd.), the “TOMAID (registered trademark)” series (T&K TOKA Corporation), the "KPI-MX” series (Kawamura Sangyo Co., Ltd.), “HPC-1000” and “HPC-2100D” (both manufactured by Showa Denko Materials K.K.).
- the content of the other resin relative to the F particles is preferably 1 to 25% by mass.
- the dispersion may further contain additives such as a thixotropic agent, 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 release agent, and a flame retardant.
- additives such as a thixotropic agent, 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 release agent, and a flame retardant.
- This dispersion liquid can be obtained by mixing F particles, a water-soluble polymer, water, and, if necessary, the above-mentioned silicone-based surfactant, an alcohol having 1 to 6 carbon atoms, other dispersion media, inorganic fillers, other resins, additives, etc.
- the dispersion may be obtained by mixing the F particles, the water-soluble polymer, and water all at once, or may be mixed separately and in sequence, or a master batch of these may be prepared in advance and then mixed with the remaining components. There is no particular restriction on the order of mixing, and the mixing method may be either mixing all at once or mixing in several separate batches.
- a cellulose ether used as the water-soluble polymer, it may be added as a powder or an aqueous solution thereof, or may be added in a state dispersed or dissolved in a liquid defoaming agent or the like.
- a silicone surfactant When a silicone surfactant is further mixed, it may be added as it is or in the form of an aqueous solution.
- the above-mentioned alcohol having 1 to 6 carbon atoms, other dispersion medium, inorganic filler, other resin, additive, etc. are further mixed as necessary, they may be mixed when the F particles and water are mixed, or they may be mixed when the mixture is added to water.
- Mixing equipment for obtaining this dispersion includes blade-equipped stirring equipment such as a Henschel mixer, pressure kneader, Banbury mixer, and planetary mixer, media-equipped grinding equipment such as a ball mill, attritor, basket mill, sand mill, sand grinder, Dyno Mill, Dispermat, SC Mill, spike mill, and agitator mill, and dispersing equipment equipped with other mechanisms such as a microfluidizer, nanomizer, 8%, ultrasonic homogenizer, dissolver, disperser, high-speed impeller, thin film swirling high-speed mixer, centrifugal mixer, and V-type mixer.
- blade-equipped stirring equipment such as a Henschel mixer, pressure kneader, Banbury mixer, and planetary mixer
- media-equipped grinding equipment such as a ball mill, attritor, basket mill, sand mill, sand grinder, Dyno Mill, Dispermat, SC Mill, spike mill, and agitator mill
- the content of F particles in this dispersion is preferably 25% by mass or more, and more preferably 35% by mass or more.
- the content of F particles is preferably 75% by mass or less, and more preferably 60% by mass or less.
- the content of the water-soluble polymer in the present dispersion is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, based on the total mass of the present dispersion.
- the content of the water-soluble polymer is preferably 1% by mass or less, more preferably 0.1% by mass or less, based on the total mass of the present dispersion.
- the ratio of the content of the water-soluble polymer to the content of the F particles in the present dispersion is preferably 0.001 or more, more preferably 0.003 or more. This ratio is preferably 0.05 or less, more preferably 0.03 or less, and even more preferably 0.01 or less.
- the water content in this dispersion is preferably 25% by mass or more, and more preferably 40% by mass or more.
- the water content is preferably less than 70% by mass, and more preferably 65% by mass or less.
- the water content in this dispersion is preferably 60 to 180% by mass relative to the F particle content.
- the viscosity of the present dispersion is preferably 500 mPa ⁇ s or more, more preferably 1000 mPa ⁇ s or more.
- the viscosity of the present dispersion is preferably 10000 mPa ⁇ s or less, more preferably 5000 mPa ⁇ s or less.
- the present dispersion has excellent coatability and is easy to form a molded product such as a coating film (polymer layer) having a desired thickness.
- the present dispersion having a viscosity in this range is easy to highly express the physical properties of the F polymer in a molded product formed therefrom.
- the thixotropy ratio of the present dispersion is preferably 1.0 to 2.5, in which case the present dispersion has excellent coatability and homogeneity, and is likely to produce a denser molded product.
- the pH of the present dispersion is preferably 8 or more, more preferably more than 8, and even more preferably 8.1 or more.
- the pH of the present dispersion is preferably 11 or less, more preferably 10 or less.
- the above-mentioned mechanism of action is easily manifested.
- the present dispersion in which the water-soluble polymer is a vinyl alcohol-based polymer or cellulose ether and is in such a pH range is easily promoted to moderately promote the denaturation of the water-soluble polymer in the liquid, and the liquid properties such as the foamability of the liquid are easily improved.
- the pH of the present dispersion can be adjusted with a pH adjuster (an amine such as ethanolamine, ammonia, citric acid, etc.) or a pH buffer (tris(hydroxymethyl)aminomethane, ethylenediaminetetraacetic acid, ammonium hydrogen carbonate, ammonium carbonate, ammonium acetate, etc.).
- a pH adjuster an amine such as ethanolamine, ammonia, citric acid, etc.
- a pH buffer tris(hydroxymethyl)aminomethane, ethylenediaminetetraacetic acid, ammonium hydrogen carbonate, ammonium carbonate, ammonium acetate, etc.
- the dielectric constant of the molded product formed from this dispersion is preferably 2.4 or less, more preferably 2.0 or less.
- the dielectric constant is preferably greater than 1.0.
- the dielectric tangent of the molded product is preferably 0.0022 or less, more preferably 0.0020 or less.
- the dielectric tangent is preferably greater than 0.0010.
- the thermal conductivity of the molded product is preferably 1 W/m ⁇ K or more, more preferably 3 W/m ⁇ K or more.
- a molded product such as a sheet containing the F polymer can be formed.
- the sheet obtained by extrusion may be further cast by press molding, calendar molding, etc.
- the sheet is preferably further heated to remove the liquid dispersion medium and to bake the F polymer.
- the thickness of the sheet formed from the present dispersion is preferably 1 to 1000 ⁇ m.
- the suitable ranges of the dielectric constant, dielectric dissipation factor and thermal conductivity of the sheet are the same as those of the above-mentioned molded product.
- 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 means a value obtained by measuring the linear expansion coefficient of a test piece in the range of 25° C. to 260° C. according to the measurement method specified in JIS C 6471:1995.
- Such a sheet can be laminated on a substrate to form a laminate.
- methods for producing a laminate include a method of extruding the present dispersion onto the substrate, and a method of thermocompression bonding the sheet and the substrate.
- the substrate include metal substrates such as metal foils of copper, nickel, aluminum, titanium, alloys thereof, etc.; films of heat-resistant resins such as polyimide, polyamide, polyetheramide, polyphenylene sulfide, polyaryl ether ketone, polyamideimide, liquid crystalline polyester, and tetrafluoroethylene polymers; prepreg substrates (precursors of fiber-reinforced resin substrates), ceramic substrates such as silicon carbide, aluminum nitride, and silicon nitride; and glass substrates.
- the shape of the substrate may be flat, curved, or uneven, and may be any of a foil, plate, film, and fiber shape.
- the ten-point average roughness of the surface of the substrate is preferably 0.01 to 0.05 ⁇ m.
- the surface of the substrate may be surface-treated with a silane coupling agent or plasma-treated.
- a silane coupling agent having a functional group such as 3-aminopropyltriethoxysilane, vinyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, or 3-isocyanatepropyltriethoxysilane is preferable.
- the peel strength between the sheet and the substrate is preferably 10 to 100 N/cm.
- the dispersion is placed on the surface of a substrate and heated 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 composed of the substrate and an F layer can be obtained.
- the F layer is preferably formed by disposing the dispersion on the surface of a substrate, heating to remove the liquid dispersion medium, and further heating to bake the F polymer. By separating the substrate from such a laminate, a sheet containing the F polymer is obtained.
- the substrate may be the same as the substrate that can be laminated with the above-mentioned sheet, and the preferred embodiments thereof are also the same.
- Methods for applying the present dispersion include coating, droplet discharging, and immersion methods, and roll coating, knife coating, bar coating, die coating, and spraying are preferred.
- the heating for removing the liquid dispersion medium is preferably performed at 100 to 200° C. for 0.1 to 30 minutes. In this heating, the liquid dispersion medium does not need to be completely removed, but only needs to be removed to the extent that the layer formed by the packing of the F particles can maintain a self-supporting film. In addition, when heating, air may be blown onto the surface to promote the removal of the liquid dispersion medium by air drying.
- the heating for baking the F polymer is preferably carried out at a temperature equal to or higher than the melting temperature of the F polymer, more preferably at 360 to 400° C. for 0.1 to 30 minutes.
- the heating device for each heating may be an oven or 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 rays, etc.).
- the heating may be carried out under normal pressure or under reduced pressure.
- the atmosphere in each heating step may be either an air atmosphere or an inert gas atmosphere (helium gas, neon gas, argon gas, nitrogen gas, etc.).
- the F layer is formed through the steps of disposing the present dispersion and heating. These steps may be performed once each, or may be repeated two or more times.
- the present dispersion may be disposed on the surface of a substrate and heated to form an F layer, and the present dispersion may be disposed on the surface of the F layer and heated to form a second F layer.
- the present dispersion may be disposed on the surface of the substrate and heated to form an F layer.
- the dispersion may be disposed on only one surface of the substrate, or on both surfaces of the substrate.
- a laminate having a substrate layer and an F layer on one surface of the substrate layer is obtained, and 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 ⁇ m.
- Suitable specific examples of the laminate 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 preferred ranges of the thickness, dielectric constant, dielectric tangent, thermal conductivity, linear expansion coefficient, and peel strength between the F layer and the substrate layer of the F layer are the same as the preferred ranges of the thickness, dielectric constant, dielectric tangent, thermal conductivity, linear expansion coefficient, and peel strength between the sheet and the substrate of the sheet formed from the above-mentioned dispersion.
- the dispersion is useful as a material for imparting insulating properties, heat resistance, corrosion resistance, chemical resistance, water resistance, impact resistance, and thermal conductivity.
- the present dispersion can be used in printed wiring boards, thermal interface materials, substrates for power modules, coils used in power devices such as motors, in-vehicle 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 dispersion is also useful as an adhesive for bonding parts.
- the dispersion can be used for bonding ceramic parts, metal parts, electronic parts such as IC chips, resistors, and capacitors on substrates of semiconductor elements and module parts, bonding circuit boards and heat sinks, and bonding LED chips to substrates.
- Molded articles such as sheets and laminates formed from the present dispersion are useful as antenna parts, printed circuit boards, aircraft parts, automobile parts, sports equipment, food industry products, heat dissipation parts, and the like.
- 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, for fuel cells, etc.), 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, etc.), and other applications.
- tension ropes tension ropes, wear pads, wear strips, tube lamps, test sockets, wafer guides, wear parts of centrifugal pumps, chemical and water supply pumps, tools (shovels, files, hacksaws, saws, etc.), boilers, hoppers, pipes, ovens, baking molds, chutes, racket strings, dies, toilets, container coating materials, heat dissipation boards mounted for power devices, heat dissipation members for wireless communication devices, transistors, thyristors, rectifiers, transformers, power MOS FETs, CPUs, heat dissipation fins, metal heat sinks, blades for windmills, wind power generation equipment, aircraft, etc., housings for personal computers and displays, electronic device materials, interior and exterior parts of automobiles, processing machines and vacuum ovens that perform heat treatment under low oxygen conditions, sealing materials for plasma treatment devices, heat dissipation parts in treatment units for sputtering and various dry etching devices, and electromagnetic wave shields.
- Sheets and other molded articles and laminates formed from this dispersion are useful as electronic substrate materials such as flexible printed wiring boards and rigid printed wiring boards, as protective films and heat dissipation substrates, particularly heat dissipation substrates for automobiles.
- the dispersions can also be used as coatings for coating F polymers on feedthroughs through battery or capacitor housings made of light metals such as aluminum, magnesium, titanium, silicon carbide, and alloys thereof.
- feedthroughs include those in which the housing has an opening with a conductor passing through a glass material that seals the opening.
- the glass material may be a glass ceramic material, and specific examples thereof include the materials described in JP-A-2018-502417.
- the conductor may be a material suitable for an electrode material of a battery or a capacitor, for example, copper or a copper alloy for a cathode of a battery.
- the conductor may be made of different materials on the inside and outside of the housing.
- the F polymer in this dispersion particularly the heat-fusible F polymer containing oxygen-containing polar groups, has excellent adhesion, so when used to cover such feedthroughs, it can bond the glass material and the housing to a high degree.
- the F polymer has excellent chemical resistance, so it can highly inhibit corrosion of the glass material.
- a battery that uses an electrolyte containing lithium fluoride salt and has a feedthrough covered with the F polymer from this dispersion not only has excellent airtightness, but also has excellent durability because erosion of the glass material in the feedthrough due to the generation of hydrofluoric acid is inhibited.
- F Particle 1 Particles of a tetrafluoroethylene polymer (melting temperature: 300° C.) containing 97.9 mol %, 0.1 mol %, and 2.0 mol % of TFE units, NAH units, and PPVE units, in that order, and having 1,000 carbonyl group-containing groups per 1 ⁇ 10 6 main chain carbon atoms (D50: 2.0 ⁇ m, specific surface area: 7 m 2 /g).
- F Particles 2 Particles made of a polymer (melting temperature 305° C.) containing 97.5 mol % TFE units and 2.5 mol % PPVE units, in that order, and having no oxygen-containing polar group (D50: 1.8 ⁇ m, specific surface area: 9 m 2 /g).
- the pot was rolled at 150 rpm for 1 hour to obtain a dispersion 1 (viscosity: 1000 mPa s, pH: 8.4) containing F particles 1 (35 parts by mass), hydroxyethyl cellulose (0.1 parts by mass), silicone surfactant (5 parts by mass), water (50 parts by mass), ethanol (10 parts by mass), and ethanolamine, and having a cation concentration of 2 ppm.
- the cation concentration is the total concentration of sodium ions and potassium ions (hereinafter the same).
- Dispersion liquid 2 (viscosity: 2000 mPa s) containing F particles 1 (35 parts by mass), hydroxyethyl cellulose (0.1 parts by mass), a silicone-based surfactant (5 parts by mass), and water (60 parts by mass) and having a cation concentration of 1 ppm was obtained in the same manner as in Example 1, except that ethanol was not added.
- Example 3 Dispersion 3 (viscosity: 2000 mPa s) containing F particles 1 (35 parts by mass), hydroxyethyl cellulose (0.1 parts by mass), a silicone-based surfactant (5 parts by mass), and water (60 parts by mass) and having a cation concentration of 1100 ppm was obtained in the same manner as in Example 1, except that ethanol was not added and the salt content of each component was not adjusted.
- Example 4 After each component was desalted and the salt content of each component was adjusted, F particles 2, polyvinyl alcohol, and water were added to the pot, and zirconia balls were then added. The pot was then rolled at 150 rpm for 1 hour to obtain dispersion liquid 4 containing F particles 2 (35 parts by mass), polyvinyl alcohol (0.1 parts by mass), and water (64.9 parts by mass) and having a cation concentration of 3 ppm.
- Example 5 In the same manner as in Example 4, dispersion 5 containing F particles 2 (35 parts by mass), polyvinyl alcohol (0.1 parts by mass), a silicone surfactant (5 parts by mass), and water (59.9 parts by mass) and having a cation concentration of 0.04 ppm was obtained.
- Example 6 Dispersion liquid 6 containing F particles 2 (35 parts by mass), polyvinyl alcohol (0.1 parts by mass), a silicone-based surfactant (5 parts by mass), and water (59.9 parts by mass) and having a cation concentration of 2000 ppm was obtained in the same manner as in Example 4, except that the salt content of each component was not adjusted.
- Example 7 Dispersion 7 (viscosity: 950 mPa ⁇ s, pH: 7.7) having a cation concentration of 2 ppm was obtained in the same manner as in Example 1, except for adjusting the amount of ethanolamine used.
- Example 8 Dispersion 8 (viscosity: 1100 mPa ⁇ s, pH: 11.1) having a cation concentration of 2 ppm was obtained in the same manner as in Example 1, except that ethanolamine was not used.
- Dispersibility of Dispersions Containing Inorganic Filler Dispersions 4 to 6 were each used to evaluate the behavior when preparing a dispersion further containing an inorganic filler, and the dispersibility of the resulting dispersion. Specifically, 100 parts by mass of Dispersion 4 and 50 parts by mass of silica filler (D50: 0.6 ⁇ m) were put into a pot, and zirconia balls were then put in. The pot was then rolled at 150 rpm for 1 hour to prepare Dispersion 4′ containing silica filler, and the state was visually evaluated after leaving it to stand, and it was found to be well dispersed without any sedimentation or the like. Dispersion 5' prepared in the same manner as above using Dispersion 5 contained some sediment and had poor dispersibility. Dispersion 6' prepared in the same manner as above using dispersion 6 was significantly thickened and gelation occurred in some parts.
- a laminate was produced using each of the dispersions 1 to 3, and the handleability and the polymer layer formed were evaluated. Specifically, by a roll-to-roll process, each dispersion was applied to one surface of a substrate (polyimide film (PI Advanced Materials'"FG-100": thickness 25 ⁇ m) by a small-diameter gravure reverse method to form a coating layer, and the substrate was passed through a ventilation drying oven (oven temperature 150 ° C.) for 3 minutes to remove water and form a dry film. Similarly, each dispersion was applied to the other surface of the substrate to form a coating layer, and the substrate was dried to form a dry film.
- PI Advanced Materials' PI Advanced Materials'
- FG-100 thickness 25 ⁇ m
- Dispersion 1 gave a transparent, smooth polymer layer without bubbles on the surface of the coating layer and without defects or streaks on the surface.
- Dispersion 2 some bubbles were observed on the surface of the coating layer, and the obtained polymer layer was slightly less transparent due to coloring.
- Dispersion 3 had foaming on the surface of the coating layer, discoloration of the polymer layer, and surface defects.
- Dispersion 1 gave a transparent, smooth polymer layer without bubbles on the surface of the coating layer and without defects or streaks on the surface.
- Dispersions 7 and 8 some bubbles were observed on the surface of the coating layer, and the obtained polymer layer had slightly poor transparency.
- the dispersion of the present invention has excellent dispersion stability and ease of handling.
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Abstract
Description
特許文献1には、25℃でのpH及びテトラフルオロエチレン系ポリマーの固形分濃度が所定範囲であり、金属イオン含有量が水性分散液全体に対して100ppm未満である水性分散液が提案されている。特許文献2には、ポリフッ化ビニリデンの粒子、特定の非イオン系界面活性剤、特定の高分子界面活性剤及び分散媒を含み、ナトリウムイオン、カリウムイオン、アンモニウムイオンの含有量がそれぞれ所定量以下である分散液が提案されている。
本発明者らは、テトラフルオロエチレン系ポリマーと特定の水溶性高分子と水とを含み、液中のアルカリ金属イオン及びアルカリ土類金属イオンの濃度を特定範囲に制御した水性分散液は、分散安定性に優れ、泡立ちが抑制され取扱いやすいことを知見した。また、かかる分散液から形成されるポリマー層等の成形物は、テトラフルオロエチレン系ポリマーに基づく耐熱性、電気特性(低線膨張係数、低誘電率及び低誘電正接)等の物性に優れ、表面外観に優れることを見出し、本発明に至った。
本発明の目的は、耐熱性、電気特性(低線膨張係数、低誘電率及び低誘電正接)等の物性に優れ、表面外観に優れる成形物を形成できる、分散安定性及び取扱い性に優れる、テトラフルオロエチレン系ポリマーを含む水性分散液の提供である。
(1) テトラフルオロエチレン系ポリマーの粒子と、ビニルアルコール系高分子、アクリル系高分子、ポリビニルピロリドン、ポリピロール、ポリチオフェン、ポリエチレンオキシド、ポリエチレンイミン及びセルロースエーテルからなる群から選ばれる少なくとも1種の極性官能基を有する水溶性高分子と、水と、を含み、アルカリ金属イオン及びアルカリ土類金属イオンからなる群から選ばれる少なくとも1種の陽イオン濃度が0.1~1000ppmである、水性分散液。
(2) 前記テトラフルオロエチレン系ポリマーが熱溶融性であり、酸素含有極性基を含有する、(1)に記載の水性分散液。
(3) 前記テトラフルオロエチレン系ポリマーの粒子の平均粒子径が1μm以上10μm未満である、(1)または(2)に記載の水性分散液。
(4) 前記テトラフルオロエチレン系ポリマーの粒子の含有量が25質量%以上である、(1)~(3)のいずれかに記載の水性分散液。
(5) 前記水溶性高分子の含有量が、前記テトラフルオロエチレン系ポリマーの粒子に対して5質量%以下である、(1)~(4)のいずれかに記載の水性分散液。
(6) 前記水溶性高分子がビニルアルコール系高分子である、(1)~(5)のいずれかに記載の水性分散液。
(7) 前記水溶性高分子がセルロースエーテルである、(1)~(5)のいずれかに記載の水性分散液。
(8) 前記セルロースエーテルが、カルボキシアルキルセルロース、ヒドロキシアルキルセルロース又はヒドロキシアルキルアルキルセルロースである、(7)に記載の水性分散液。
(9) さらに、シリコーン系界面活性剤を含有する、(1)~(8)のいずれかに記載の水性分散液。
(10) さらに、炭素数1~6のアルコールを含有する、(1)~(9)のいずれかに記載の水性分散液。
(11) 粘度が、500~10000mPa・sである、(1)~(10)のいずれかに記載の水性分散液。
(12) チキソ比が、1.0~2.5である、(1)~(11)のいずれかに記載の水性分散液。
(13) 前記陽イオンが、ナトリウムイオン又はカリウムイオンの少なくとも1種である、(1)~(12)のいずれかに記載の水性分散液。
(14) pHが、8超11以下である、(1)~(13)のいずれかに記載の水性分散液。
(15) (1)~(14)のいずれかに記載の水性分散液を基材の表面に配置し加熱して、前記テトラフルオロエチレン系ポリマーを含むポリマー層を形成し、前記基材で構成される基材層と前記ポリマー層とをこの順で有する積層体を得る、積層体の製造方法。
「平均粒子径(D50)」は、レーザー回折・散乱法によって求められる、粒子又はフィラーの体積基準累積50%径である。すなわち、レーザー回折・散乱法によって粒度分布を測定し、粒子の集団の全体積を100%として累積カーブを求め、その累積カーブ上で累積体積が50%となる点の粒子径である。
粒子又はフィラーのD50は、粒子を水中に分散させ、レーザー回折・散乱式の粒度分布測定装置(堀場製作所社製、LA-920測定器)を用いたレーザー回折・散乱法により分析して求められる。
「平均粒子径(D90)」は、D50と同様にして求められる、粒子の体積基準累積90%径である。
粒子又はフィラーの比表面積は、ガス吸着(定容法)BET多点法で粒子を測定し算出される値であり、ガス吸着式細孔分布測定器(製品名 NOVA4200e、Quantachrome Instruments社製)を使用して求められる。
「溶融温度」は、示差走査熱量測定(DSC)法で測定したポリマーの融解ピークの最大値に対応する温度である。
「ガラス転移点(Tg)」は、動的粘弾性測定(DMA)法でポリマーを分析して測定される値である。
「粘度」は、B型粘度計を用いて、25℃で回転数が30rpmの条件下で分散液を測定して求められる。測定を3回繰り返し、3回分の測定値の平均値とする。
「チキソ比」とは、分散液の、回転数が30rpmの条件で測定される粘度η1を、回転数が60rpmの条件で測定される粘度η2で除して算出される値である。それぞれの粘度の測定は、3回繰り返し、3回分の測定値の平均値とする。
溶媒又は溶液の「表面張力」は、表面張力計を用い、25℃にてウィルヘルミー法で測定した値である。
界面活性剤の「HLB(Hydrophilic-Lipophilic Balance)値」は、グリフィン法により、次の算出式で定義される値である。
HLB値=20×[親水部の化学式量の総和]/分子量
セルロースエーテルの「置換度」は、エーテル化度とも言い、セルロースのグルコース環上にある3つの水酸基のうちアルコキシル基に置換された水酸基の個数(平均値)を表す。置換度は理論的に0~3の間の値を有することができ、一般的に置換基が高いほど親水性となる。置換度は、第18改正日本薬局方記載のヒドロキシプロピルメチルセルロースの置換度分析方法により測定される値を換算して求められる。
水性分散液の「陽イオン濃度」は、水性分散液の乾固物を1000℃にて4分間灰化処理して得られる測定サンプルに含まれる陽イオンの含有量をフレームレス原子吸光分析によって求め、その値と水性分散液の質量とから求められる値である。
ポリマーにおける「単位」とは、モノマーの重合により形成された前記モノマーに基づく原子団を意味する。単位は、重合反応によって直接形成された単位であってもよく、ポリマーを処理することによって前記単位の一部が別の構造に変換された単位であってもよい。以下、モノマーaに基づく単位を、単に「モノマーa単位」とも記す。
本分散液は分散安定性及び取扱い性に優れており、かかる分散液から形成される塗膜(ポリマー層)等の成形物は、テトラフルオロエチレン系ポリマーに基づく耐熱性、電気特性(低線膨張係数、低誘電率及び低誘電正接)等の物性に優れ、その表面外観に優れる。なお、本明細書において「表面外観に優れる」とは、「表面の荒れが少ない」等の表面平滑性に優れること、又は「表面にスジ、クラックや欠点等がない」等の、視認又は分析機器で観察される外観に優れることのいずれをも包含する。
本分散液が分散安定性に優れ、泡立ちが抑制され取扱い性に優れる理由は必ずしも明確ではないが、以下の様に考えられる。
本分散液においては、その陽イオン濃度を0.1~1000ppmの特定範囲に制御する。つまり、分散液中の陽イオン濃度を低めすぎないことで、陽イオンによる水溶性高分子の凝集(塩析)を緩やかに促すことで、その増粘効果と泡立ちの抑制効果とをバランスさせていると考えられる。また、陽イオン濃度を高めすぎないことで、水溶性高分子の過度な凝集による、本分散液の透明性及び分散安定性の低下を抑制していると推定される。さらに、本分散液から形成される成形物中に陽イオンが塩として残留することによる、電気特性等の物性低下を抑制していると考えられる。
かかる作用機構は、本分散液が、シリコーン系界面活性剤や炭素数1~6のアルコールを含有する場合に一層顕著となる。特に、かかるアルコールはF粒子の液中分散性を高める反面、水溶性高分子の溶解又は膨潤も促進するため、分散液を増粘させる効果を高めてしまう。そのため、陽イオン濃度を本発明の範囲に制御することがより重要と考えられる。
前記陽イオンとしては、リチウムイオン、ナトリウムイオン、カリウムイオン、ルビジウムイオン、セシウムイオン、などのアルカリ金属イオン、およびベリリウムイオン、マグネシウムイオン、カルシウムイオン、ストロンチウムイオン、バリウムイオンなどのアルカリ土類金属イオンが挙げられる。中でも、前記陽イオンが、ナトリウムイオンおよびカリウムイオンの少なくとも1種であるのが好ましい。
上記した陽イオンとしては、Fポリマーに由来する陽イオンが挙げられる。かかる陽イオンとしては、Fポリマーを得るための重合における後処理工程でpH調整剤として使用した、水酸化ナトリウムや水酸化カリウム等の金属水酸化物に由来する陽イオンが挙げられる。
また、上記した陽イオンとしては、水溶性高分子に由来する陽イオンが挙げられる。例えば、セルロースエーテルは、精製パルプに水酸化ナトリウムや水酸化カリウム等のアルカリ溶液を接触させ、さらにエーテル化剤を作用させてセルロースに含まれるヒドロキシ基をエーテルに変換する製造法により得られるため、前記アルカリ溶液に由来する陽イオンが含まれ得る。ビニルアルコール系高分子は、ビニルエステルの重合後のケン化工程でケン化剤として使用した、水酸化ナトリウムや水酸化カリウム等の金属水酸化物に由来する陽イオンが含まれ得る。
さらに、水として、自然の源水や地下水をそのまま、又は中空糸膜や活性炭等のろ過材で浮遊物やハロゲン分を除去し必要に応じ加熱殺菌した水を用いる場合には、ミネラル分としての陽イオンが含まれ得る。
具体的には、Fポリマーを予め水洗して、その陽イオン濃度を制御する方法、水溶性高分子を洗浄液で洗浄してその陽イオン濃度を制御する方法、用いる水の陽イオン濃度を予め制御する方法等の脱塩処理が挙げられる。
また、調製後の本分散液をイオン交換樹脂で処理することで、陽イオン濃度を上記範囲に制御し調整してもよい。
Fポリマーは、熱溶融性であってもよく、非熱溶融性であってもよい。ここで、熱溶融性のポリマーとは、荷重49Nの条件下、溶融流れ速度が1~1000g/10分となる温度が存在するポリマーを意味する。
熱溶融性であるFポリマーの溶融温度は、180℃以上が好ましく、200℃以上がより好ましい。前記Fポリマーの溶融温度は、325℃以下が好ましく、320℃以下がより好ましい。この場合、本分散液から形成される塗膜(ポリマー層)等の成形物が耐熱性に優れやすい。
Fポリマーのフッ素含有量は、70質量%以上が好ましく、72~76質量%がより好ましい。
PTFEとしては、低分子量PTFE、変性PTFEが挙げられる。
低分子量PTFEの数平均分子量は、20万以下が好ましく、10万以下がより好ましく、5万以下がさらに好ましい。上記PTFEの数平均分子量は、1万以上が好ましい。なお、数平均分子量は、下式(1)に基づいて算出される値である。
Mn=2.1×1010×ΔHc-5.16 ・・・ (1)
式(1)中、Mnは、低分子量PTFEの数平均分子量を、ΔHcは、示差走査熱量分析法により測定される低分子量PTFEの結晶化熱量(cal/g)を、それぞれ示す。
PAVEは、CF2=CFOCF3、CF2=CFOCF2CF3及びCF2=CFOCF2CF2CF3(以下、「PPVE」とも記す。)が好ましく、PPVEがより好ましい。
水酸基含有基は、アルコール性水酸基を含有する基が好ましく、-CF2CH2OH及び-C(CF3)2OHがより好ましい。
カルボニル基含有基は、カルボキシル基、アルコキシカルボニル基、アミド基、イソシアネート基、カルバメート基(-OC(O)NH2)、酸無水物残基(-C(O)OC(O)-)、イミド残基(-C(O)NHC(O)-等)及びカーボネート基(-OC(O)O-)が好ましく、酸無水物残基がより好ましい。
Fポリマーが酸素含有極性基を有する場合、Fポリマーにおける酸素含有極性基の数は、主鎖の炭素数1×106個あたり、10~5000個が好ましく、100~3000個がより好ましい。なお、Fポリマーにおける酸素含有極性基の数は、ポリマーの組成又は国際公開第2020/145133号に記載の方法によって定量できる。
カルボニル基含有基を有するモノマーは、無水イタコン酸、無水シトラコン酸及び5-ノルボルネン-2,3-ジカルボン酸無水物(以下、「NAH」とも記す。)が好ましく、NAHがより好ましい。
また、F粒子のD90は8μm以下が好ましく、6μm以下がより好ましい。F粒子のD90が上記範囲以下であると、上述した作用機構がより発現しやすくなり、粗大粒子の数が少ない本分散液が得られやすい。
F粒子の比表面積は、1~25m2/gであるのが好ましく、6~15m2/gがより好ましい。
F粒子は、溶融温度が200~325℃である、酸素含有極性基を有する熱溶融性Fポリマーの粒子であるのがより好ましい。この場合、上述した作用機構がより発現されてF粒子の凝集も抑制されやすい。
F粒子は、Fポリマー以外の樹脂や無機化合物を含んでいてもよく、FポリマーをコアとしFポリマー以外の樹脂又は無機化合物をシェルとするコア-シェル構造を形成していてもよく、FポリマーをシェルとしFポリマー以外の樹脂又は無機化合物をコアとするコア-シェル構造を形成していてもよい。
ここで、Fポリマー以外の樹脂としては、芳香族ポリエステル、ポリアミドイミド、ポリイミド、マレイミドが挙げられ、無機化合物としては、シリカ、窒化ホウ素が挙げられる。
F粒子は、1種を用いてもよく、2種以上を用いてもよい。
上述した作用機構がより発現しやすく、本分散液のレオロジー物性が向上して、造膜性等の取扱性がより向上しやすい観点から、極性官能基としては、エーテル結合、エステル結合、アミド結合、イミド結合、チオエーテル結合、スルフィド結合、ジスルフィド結合、カルボニル基含有基、水酸基含有基、チオール基、スルフィド基、スルホニル基、スルホキシル基、アミノ基、アミド基が好ましく、水酸基含有基がより好ましく、ノニオン性水酸基がさらに好ましい。極性官能基は、ポリマーの主鎖又は側鎖のいずれに有していてもよい。
なお、ポリビニルピロリドン、ポリピロール、ポリチオフェン、ポリエチレンオキシド、ポリエチレンイミンがさらに水酸基を有する場合は、ポリマーの主鎖末端に水酸基を有しているのが好ましい。
ビニルアルコール系高分子の具体例としては、「エスレック(登録商標)B」シリーズ、「エスレック(登録商標)K(KS)」シリーズ、「エスレック(登録商標)SV」シリーズ(以上、積水化学工業社製)」、「モビタール(登録商標)」シリーズ(クラレ社製)が挙げられる。
アクリル系高分子としては、ポリアクリル酸、ポリアクリル酸ナトリウム、アクリル酸/マレイン酸共重合ナトリウム、アクリル酸/スルホン酸系モノマー共重合体ナトリウム等のポリアクリル酸の塩、ポリアクリル酸メチル、ポリアクリル酸エチル等のポリアクリレート、ポリ-α-ハロアクリレート、ポリ-α-シアノアクリレート、ポリアクリルアミドが挙げられる。
カルボキシアルキルセルロースとしては、カルボキシメチルセルロース等が挙げられる。
ヒドロキシアルキルセルロースとしては、ヒドロキシメチルセルロース、ヒドロキシエチルセルロース、ヒドロキシプロピルセルロース等が挙げられる。
ヒドロキシアルキルアルキルセルロースとしては、ヒドロキシプロピルメチルセルロース、ヒドロキシエチルメチルセルロース、ヒドロキシエチルエチルセルロース、ヒドロキシエチルエチルメチルセルロース等が挙げられる。これらは1種類を単独で用いてもよく、2種以上を併用してもよい。
中でも、カルボキシアルキルセルロース、ヒドロキシアルキルセルロース又はヒドロキシアルキルアルキルセルロースが好ましく、ヒドロキシアルキルセルロースがより好ましく、ヒドロキシエチルセルロースがさらに好ましい。
セルロースエーテルの具体例としては、「サンローズ(登録商標)」シリーズ(日本製紙社製)、「メトローズ(登録商標)」シリーズ(信越化学工業社製)、「HEC CFグレード」(住友精化社製)が挙げられる。
水溶性高分子の重量平均分子量は、1000以上が好ましく、10000以上がより好ましく、100000以上がさらに好ましく、300000以上が特に好ましい。水溶性高分子の重量平均分子量は、1000000以下が好ましく、500000以下がより好ましい。この場合、本分散液が分散安定性等の物性に優れやすい。
本分散液は、その粘度及びチキソ比を調整する観点から、上記した水溶性高分子以外の粘度調節剤をさらに含有していてもよい。
本分散液は、その粘度及びチキソ比を調整する観点から、上記した水溶性高分子以外の粘度調節剤をさらに含有していてもよい。
また、ポリオキシアルキレン変性ジメチルシロキサンに含まれるオキシアルキレン基は、1種のオキシアルキレン基のみからなっていてもよく、2種以上のオキシアルキレン基からなっていてもよい。後者の場合、異種のオキシアルキレン基は、ランダム状に連結していてもよく、ブロック状に連結してもよい。
これらは1種類を用いてもよく、2種以上を用いてもよい。2種以上の前記アルコールを用いる場合、それらは互いに相溶するのが好ましい。
無機フィラーの形状は、球状、針状(繊維状)、板状のいずれであってもよく、具体的には、球状、鱗片状、層状、葉片状、杏仁状、柱状、鶏冠状、等軸状、葉状、雲母状、ブロック状、平板状、楔状、ロゼット状、網目状、角柱状であってもよい。
無機フィラーとしては、例えば石英粉、シリカ、ウォラストナイト、タルク、窒化ケイ素、炭化ケイ素、雲母等のケイ素化合物;窒化ホウ素、窒化アルミニウム等の窒素化合物;酸化アルミニウム、酸化亜鉛、酸化チタン、酸化セリウム、酸化ベリリウム、酸化マグネシウム、酸化ニッケル、酸化バナジウム、酸化銅、酸化鉄、酸化銀等の金属酸化物;炭素繊維;グラファイト、グラフェン、カーボンナノチューブ等の炭素同素体;銀、銅等の金属;が挙げられる。
無機フィラーは、1種を用いてもよく、2種以上を併用してもよい。
無機フィラーのD50は、0.1~50μmが好ましい。
無機フィラーの表面は、シランカップリング剤で表面処理されていてもよい。
本分散液が無機フィラーを含む場合、本分散液における無機フィラーの含有量は、1~25質量%が好ましい。
他の樹脂としては、液晶性の芳香族ポリエステル等のポリエステル樹脂、ポリイミド樹脂、ポリアミドイミド樹脂、エポキシ樹脂、マレイミド樹脂、ウレタン樹脂、ポリフェニレンエーテル樹脂、ポリフェニレンオキシド樹脂、ポリフェニレンサルファイド樹脂が挙げられる。
他の樹脂としては、芳香族系ポリマーが好ましく、芳香族ポリイミド、芳香族ポリアミック酸、芳香族ポリアミドイミド及び芳香族ポリアミドイミドの前駆体からなる群から選ばれる少なくとも1種の芳香族イミドポリマーがより好ましい。芳香族ポリマーは本分散液中で、液状分散媒に溶解したワニスとして含まれるのが好ましい。
本分散液が他の樹脂をさらに含む場合、F粒子に対する他の樹脂の含有量は、1~25質量%が好ましい。
本分散液は、F粒子と水溶性高分子と水を一括で混合して得てもよいし、別々に順次混合してもよいし、これらのマスターバッチを予め作成し、それと残りの成分を混合してもよい。混合の順は特に制限はなく、また混合の方法も一括混合でも複数回に分割して混合してもよい。
水溶性高分子としてセルロースエーテルを用いる場合、粉末又はその水溶液として添加してもよく、液体の消泡剤等に分散または溶解させた状態で添加してもよい。
シリコーン系界面活性剤をさらに混合する場合、そのまま又は水溶液として添加してもよい。また、前記した炭素数1~6のアルコール、他の分散媒、無機フィラー、他の樹脂、添加剤等を必要に応じてさらに混合する場合、F粒子と水との混合に際して混合してもよく、前記混合物を水に添加するに際して混合してもよい。
また、本分散液におけるF粒子の含有量に対する水溶性高分子の含有量の比は、0.001以上が好ましく、0.003以上がより好ましい。かかる含有量の比は、0.05以下が好ましく、0.03以下がより好ましく、0.01以下がさらに好ましい。
本分散液のチキソ比は、1.0~2.5が好ましい。この場合、本分散液は、塗工性及び均質性に優れ、より緻密な成形物を生成しやすい。
かかる本分散液のpHは、pH調整剤(エタノールアミンなどのアミン、アンモニア、クエン酸等。)又はpH緩衝剤(トリス(ヒドロキシメチル)アミノメタン、エチレンジアミン四酢酸、炭酸水素アンモニウム、炭酸アンモニウム、酢酸アンモニウム等。)によって調整できる。
シートの誘電率、誘電正接及び熱伝導率の好適な範囲は、それぞれ、上述した成形物の誘電率、誘電正接及び熱伝導率の範囲と同様である。なお、シートにおける熱伝導率とは、シートの面内方向における熱伝導率を意味する。
シートの線膨張係数は、100ppm/℃以下が好ましく、80ppm/℃以下がより好ましい。シートの線膨張係数の下限は、30ppm/℃である。なお、線膨張係数は、JIS C 6471:1995に規定される測定方法に従って、25℃以上260℃以下の範囲における、試験片の線膨張係数を測定した値を意味する。
基材としては、銅、ニッケル、アルミニウム、チタン、それらの合金等の金属箔等の金属基板;ポリイミド、ポリアミド、ポリエーテルアミド、ポリフェニレンスルフィド、ポリアリルエーテルケトン、ポリアミドイミド、液晶性ポリエステル、テトラフルオロエチレン系ポリマー等の耐熱性樹脂のフィルム;プリプレグ基板(繊維強化樹脂基板の前駆体)、炭化ケイ素、窒化アルミニウム、窒化ケイ素等のセラミックス基板;ガラス基板が挙げられる。
基材の表面の十点平均粗さは、0.01~0.05μmが好ましい。
基材の表面は、シランカップリング剤により表面処理されていてもよく、プラズマ処理されていてもよい。かかるシランカップリング剤としては、3-アミノプロピルトリエトキシシラン、ビニルトリメトキシシラン、3-メルカプトプロピルトリメトキシシラン、3-グリシドキシプロピルメチルジエトキシシラン、3-メタクリロキシプロピルトリエトキシシラン、3-イソシアネートプロピルトリエトキシシラン等の官能基を有するシランカップリング剤が好ましい。
シートと基材との剥離強度は、10~100N/cmが好ましい。
F層は、本分散液を基材の表面に配置し、加熱して液状分散媒を除去し、さらに加熱してFポリマーを焼成して形成するのが好ましい。かかる積層体から基材を分離すれば、Fポリマーを含むシートを得られる。
基材としては、上述のシートと積層できる基材と同様のものが挙げられ、その好適態様も同様である。
液状分散媒の除去に際する加熱は、100~200℃にて、0.1~30分間で行うのが好ましい。この際の加熱において液状分散媒は、完全に除去する必要はなく、F粒子のパッキングにより形成される層が自立膜を維持できる程度まで除去すればよい。また、加熱に際しては、空気を吹き付け、風乾によって液状分散媒の除去を促してもよい。
それぞれの加熱における加熱装置としては、オーブン、通風乾燥炉が挙げられる。装置における熱源は、接触式の熱源(熱風、熱板等)であってもよく、非接触式の熱源(赤外線等)であってもよい。
また、それぞれの加熱は、常圧下で行ってもよく、減圧下で行ってもよい。
また、それぞれの加熱における雰囲気は、空気雰囲気、不活性ガス(ヘリウムガス、ネオンガス、アルゴンガス、窒素ガス等)雰囲気のいずれであってもよい。
本分散液は、基材の一方の表面にのみ配置してもよく、基材の両面に配置してもよい。前者の場合、基材層と、かかる基材層の片方の表面にF層を有する積層体が得られ、後者の場合、基材層と、かかる基材層の両方の表面にF層を有する積層体が得られる。
F層の厚さは、積層体の用途によっても異なるが、1~1000μmの範囲が好ましい。
F層の厚さ、誘電率、誘電正接、熱伝導率、線膨張係数、F層と基材層との剥離強度の好適範囲は、上述の本分散液から形成されるシートにおける、厚さ、誘電率、誘電正接、熱伝導率、線膨張係数、シートと基材との剥離強度の好適範囲と同様である。
本分散液は、具体的には、プリント配線板、熱インターフェース材、パワーモジュール用基板、モーター等の動力装置で使用されるコイル、車載エンジン、熱交換器、バイアル瓶、注射筒(シリンジ)、アンプル、医療用ワイヤー、リチウムイオン電池等の二次電池、リチウム電池等の一次電池、ラジカル電池、太陽電池、燃料電池、リチウムイオンキャパシタ、ハイブリッドキャパシタ、キャパシタ、コンデンサ(アルミニウム電解コンデンサ、タンタル電解コンデンサ等)、エレクトロクロミック素子、電気化学スイッチング素子、電極のバインダー、電極のセパレーター、電極(正極、負極)に使用できる。
また、本分散液は部品を接着する接着剤としても有用である。具体的には、本分散液は、セラミックス部品の接着、金属部品の接着、半導体素子やモジュール部品の基板におけるICチップや抵抗、コンデンサ等の電子部品の接着、回路基板と放熱板の接着、LEDチップの基板への接着に使用できる。
具体的には、電線被覆材(航空機用電線等)、電気自動車等のモーター等に使用されるエナメル線被覆材、電気絶縁性テープ、石油掘削用絶縁テープ、石油輸送ホース、水素タンク、プリント基板用材料、分離膜(精密濾過膜、限外濾過膜、逆浸透膜、イオン交換膜、透析膜、気体分離膜等)、電極バインダー(リチウム二次電池用、燃料電池用等)、コピーロール、家具、自動車ダッシュボート、家電製品等のカバー、摺動部材(荷重軸受、ヨー軸受、すべり軸、バルブ、ベアリング、ブッシュ、シール、スラストワッシャ、ウェアリング、ピストン、スライドスイッチ、歯車、カム、ベルトコンベア、食品搬送用ベルト等)、テンションロープ、ウェアパッド、ウェアストリップ、チューブランプ、試験ソケット、ウェハーガイド、遠心ポンプの摩耗部品、薬品及び水供給ポンプ、工具(シャベル、やすり、きり、のこぎり等)、ボイラー、ホッパー、パイプ、オーブン、焼き型、シュート、ラケットのガット、ダイス、便器、コンテナ被覆材、パワーデバイス用実装放熱基板、無線通信デバイスの放熱部材、トランジスタ、サイリスタ、整流器、トランス、パワーMOS FET、CPU、放熱フィン、金属放熱板、風車や風力発電設備や航空機等のブレード、パソコンやディスプレイの筐体、電子デバイス材料、自動車の内外装、低酸素下で加熱処理する加工機や真空オーブン、プラズマ処理装置などのシール材、スパッタや各種ドライエッチング装置等の処理ユニット内の放熱部品、電磁波シールドとして有用である。
かかるフィードスルーとしては、ハウジングが開口部を備え、前記開口部を封止するガラス材料で貫通する導体を備えたフィードスルーが挙げられる。
ガラス材料は、ガラスセラミックス材料であってもよく、具体的には、特開表2018-502417号公報に記載される材料が挙げられる。
導体としては、バッテリー又はキャパシタの電極材料に適した材料が挙げられ、例えば、バッテリーのカソードであれば、銅、銅合金が挙げられる。導体は、ハウジングの内側と外側とで異種の材質からなっていてもよい。
1.各成分の準備
[Fポリマー]
F粒子1:TFE単位、NAH単位及びPPVE単位を、この順に97.9モル%、0.1モル%、2.0モル%含み、カルボニル基含有基を主鎖炭素数1×106個あたり1000個有するテトラフルオロエチレン系ポリマー(溶融温度:300℃)の粒子(D50:2.0μm、比表面積:7m2/g)
F粒子2:TFE単位及びPPVE単位を、この順に97.5モル%、2.5モル%含み、酸素含有極性基を有さないポリマー(溶融温度305℃)からなる粒子(D50:1.8μm、比表面積:9m2/g)
[例1]
各成分を脱塩処理し、各成分の塩分量を調整した上で、ポットに、F粒子1とヒドロキシエチルセルロース(置換度:2.5)とノニオン性のシリコーン系界面活性剤(主鎖にポリシロキサン鎖を有し、側鎖にポリエチレンオキシド基を有する。HLB値=13)と水とエタノールとエタノールアミンを投入し、ジルコニアボールを投入した。その後、150rpmにて1時間、ポットを転がして、F粒子1(35質量部)、ヒドロキシエチルセルロース(0.1質量部)、シリコーン系界面活性剤(5質量部)、水(50質量部)及びエタノール(10質量部)及びエタノールアミンを含み、陽イオン濃度が2ppmである分散液1(粘度:1000mPa・s,pH:8.4)を得た。なお、陽イオン濃度は、ナトリウムイオン及びカリウムイオンの合計濃度である(以下同様)。
エタノールを加えなかった以外は例1と同様にして、F粒子1(35質量部)、ヒドロキシエチルセルロース(0.1質量部)、シリコーン系界面活性剤(5質量部)及び水(60質量部)を含み、陽イオン濃度が1ppmである分散液2(粘度:2000mPa・s)を得た。
[例3]
エタノールを加えず、各成分の塩分量を調整しないこと以外は例1と同様にして、F粒子1(35質量部)、ヒドロキシエチルセルロース(0.1質量部)、シリコーン系界面活性剤(5質量部)及び水(60質量部)を含み、陽イオン濃度が1100ppmである分散液3(粘度:2000mPa・s)を得た。
ポットに、各成分を脱塩処理し、各成分の塩分量を調整した上で、F粒子2とポリビニルアルコールと水とを投入し、ジルコニアボールを投入した。その後、150rpmにて1時間、ポットを転がして、F粒子2(35質量部)、ポリビニルアルコール(0.1質量部)及び水(64.9質量部)を含み、陽イオン濃度が3ppmである分散液4を得た。
[例5]
例4と同様にして、F粒子2(35質量部)、ポリビニルアルコール(0.1質量部)、シリコーン系界面活性剤(5質量部)及び水(59.9質量部)を含み、陽イオン濃度が0.04ppmである分散液5を得た。
[例6]
各成分の塩分量を調整しないこと以外は、例4と同様にして、F粒子2(35質量部)、ポリビニルアルコール(0.1質量部)、シリコーン系界面活性剤(5質量部)及び水(59.9質量部)を含み、陽イオン濃度が2000ppmである分散液6を得た。
エタノールアミンの使用量を調整する以外は、例1と同様にして、陽イオン濃度が2ppmである分散液7(粘度:950mPa・s,pH:7.7)を得た。
[例8]
エタノールアミンを使用しない以外は、例1と同様にして、陽イオン濃度が2ppmである分散液8(粘度:1100mPa・s,pH:11.1)を得た。
3-1.無機フィラーを加えた分散液の分散性
分散液4~6をそれぞれ用いて、無機フィラーをさらに含有する分散液を調製する際の挙動と、得られる分散液の分散性を評価した。
具体的には、ポットに分散液4を100質量部とシリカフィラー(D50:0.6μm)50質量部とを投入し、ジルコニアボールを投入した。その後、150rpmにて1時間、ポットを転がして、シリカフィラーを含む分散液4’を調製し、静置して状態を目視で評価した結果、沈降物等は生じず良好に分散していた。
分散液5を用いて上記と同様に調製した分散液5’は、沈降物が一部生じており、分散性は悪化していた。
また、分散液6を用いて上記と同様に調製した分散液6’は著しく増粘してしまい、一部にはゲル化が起きていた。
分散液1~3をそれぞれ用いて積層体を製造し、その際の取扱い性と、形成されたポリマー層を評価した。具体的には、ロール・ツー・ロールプロセスにより、基材(ポリイミドフィルム(PI Advanced Materials社製「FG-100」:厚さ25μm)の一方の表面に、各分散液を小径グラビアリバース法で塗工して塗工層を形成し、通風乾燥炉(炉温150℃)に3分間で通過させて、水を除去してドライ膜を形成した。また、基材の他方の表面にも同様に各分散液を塗工して塗工層を形成し、乾燥してドライ膜を形成した。次いで、両面にドライ膜が形成された基材を、遠赤外線炉(炉内入口、出口付近の炉温度300℃、中心付近の炉温度360℃)に5分間で通過させてF粒子を溶融焼成し、基材の両面にポリマー層(厚さ25μm)を有する積層体を得た。
分散液1では、塗工層の表面における泡立ちがなく、透明で、表面に欠点や筋目がなく平滑なポリマー層が得られた。
分散液2では、塗工層の表面にやや泡立ちが見られ、着色により透明性がやや劣るポリマー層が得られた。
分散液3では、塗工層の表面に泡立ちがあり、ポリマー層が着色し、また表面に欠点が生じていた。
分散液1、7及び8のそれぞれを用いて、上記3-1.と同様にして、積層体を製造し、その際の取扱い性と、形成されたポリマー層を評価した。
分散液1では、塗工層の表面における泡立ちがなく、透明で、表面に欠点や筋目がなく平滑なポリマー層が得られた。
分散液7及び8では、塗工層の表面にやや泡立ちが見られ、透明性がやや劣るポリマー層が得られた。
Claims (15)
- テトラフルオロエチレン系ポリマーの粒子と、ビニルアルコール系高分子、アクリル系高分子、ポリビニルピロリドン、ポリピロール、ポリチオフェン、ポリエチレンオキシド、ポリエチレンイミン及びセルロースエーテルからなる群から選ばれる少なくとも1種である、極性官能基を有する水溶性高分子と、水と、を含み、アルカリ金属イオン及びアルカリ土類金属イオンからなる群から選ばれる少なくとも1種の陽イオンの濃度が0.1~1000ppmである、水性分散液。
- 前記テトラフルオロエチレン系ポリマーが熱溶融性であり、酸素含有極性基を含有する、請求項1に記載の水性分散液。
- 前記テトラフルオロエチレン系ポリマーの粒子の平均粒子径が1μm以上10μm未満である、請求項1に記載の水性分散液。
- 前記テトラフルオロエチレン系ポリマーの粒子の含有量が25質量%以上である、請求項1に記載の水性分散液。
- 前記水溶性高分子の含有量が、前記テトラフルオロエチレン系ポリマーの粒子に対して5質量%以下である、請求項1に記載の水性分散液。
- 前記水溶性高分子がビニルアルコール系高分子である、請求項1に記載の水性分散液。
- 前記水溶性高分子がセルロースエーテルである、請求項1に記載の水性分散液。
- 前記セルロースエーテルが、カルボキシアルキルセルロース、ヒドロキシアルキルセルロース又はヒドロキシアルキルアルキルセルロースである、請求項7に記載の水性分散液。
- さらに、シリコーン系界面活性剤を含有する、請求項1に記載の水性分散液。
- さらに、炭素数1~6のアルコールを含有する、請求項1に記載の水性分散液。
- 粘度が、500~10000mPa・sである、請求項1に記載の水性分散液。
- チキソ比が、1.0~2.5である、請求項1に記載の水性分散液。
- 前記陽イオンが、ナトリウムイオン又はカリウムイオンの少なくとも1種である、請求項1に記載の水性分散液。
- pHが8超11以下である、請求項1に記載の水性分散液。
- 請求項1~14のいずれか1項に記載の水性分散液を基材の表面に配置し加熱して、前記テトラフルオロエチレン系ポリマーを含むポリマー層を形成し、前記基材で構成される基材層と前記ポリマー層とをこの順で有する積層体を得る、積層体の製造方法。
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| JPH07258523A (ja) * | 1994-03-22 | 1995-10-09 | Toray Ind Inc | ポリエステル組成物 |
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| WO2022092036A1 (ja) * | 2020-10-29 | 2022-05-05 | Agc株式会社 | テトラフルオロエチレン系ポリマーのパウダー粒子を含む組成物、その製造方法、その組成物からの分散液の製造方法 |
| WO2022145333A1 (ja) * | 2020-12-28 | 2022-07-07 | Agc株式会社 | 水性分散液及びその製造方法 |
| WO2022153931A1 (ja) * | 2021-01-13 | 2022-07-21 | Agc株式会社 | 液状組成物の製造方法及び組成物 |
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- 2023-09-27 CN CN202380070539.1A patent/CN119968434A/zh active Pending
- 2023-09-27 WO PCT/JP2023/035169 patent/WO2024075609A1/ja not_active Ceased
- 2023-09-27 JP JP2024555751A patent/JPWO2024075609A1/ja active Pending
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| JPH07258523A (ja) * | 1994-03-22 | 1995-10-09 | Toray Ind Inc | ポリエステル組成物 |
| US20060078800A1 (en) * | 2004-10-13 | 2006-04-13 | Kazuo Konabe | Fluoropolymer dispersion and electrode composition containing same |
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| WO2022092036A1 (ja) * | 2020-10-29 | 2022-05-05 | Agc株式会社 | テトラフルオロエチレン系ポリマーのパウダー粒子を含む組成物、その製造方法、その組成物からの分散液の製造方法 |
| WO2022145333A1 (ja) * | 2020-12-28 | 2022-07-07 | Agc株式会社 | 水性分散液及びその製造方法 |
| WO2022153931A1 (ja) * | 2021-01-13 | 2022-07-21 | Agc株式会社 | 液状組成物の製造方法及び組成物 |
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| CN119968434A (zh) | 2025-05-09 |
| JPWO2024075609A1 (ja) | 2024-04-11 |
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