Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J3/00—Processes of treating or compounding macromolecular substances
  • C08J3/02—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques
  • C08J3/03—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques in aqueous media
  • C08J3/05—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques in aqueous media from solid polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/05—Alcohols; Metal alcoholates
• • 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

Definitions

• the present invention relates to a method for producing an aqueous dispersion containing particles of a tetrafluoroethylene polymer, and an aqueous dispersion.
• Tetrafluoroethylene-based polymers which have a low dielectric constant and a low dielectric loss tangent, are attracting attention.
• a material for forming an insulating layer containing such a polymer a dispersion containing particles of a tetrafluoroethylene polymer and a liquid dispersion medium is known.
• Patent Document 1 proposes a non-aqueous dispersion containing a tetrafluoroethylene polymer having an average particle diameter of less than 0.1 ⁇ m and a non-aqueous solvent such as isopropanol.
• Patent Document 2 proposes an aqueous dispersion containing polytetrafluoroethylene having a volume average particle diameter of 1 to 50 ⁇ m after dispersion and a predetermined amount of a water-soluble thickener.
• Aqueous dispersions have high versatility in equipment required for use and high selectivity in substrates to which they are coated.
• the surface tension of the tetrafluoroethylene polymer is low, its particles have low dispersibility in water, and the aqueous dispersion tends to foam, making it difficult to say that the aqueous dispersion has sufficient handling properties in applications such as coating.
• This problem tends to become noticeable when tetrafluoroethylene polymer particles having an average particle diameter of 1 ⁇ m or more are used as in Patent Document 2, and their content in the aqueous dispersion becomes high.
• defects are likely to occur on the surface of molded products such as polymer layers formed from such aqueous dispersions, and the surface appearance is likely to be impaired.
• the present inventors have demonstrated that when a predetermined amount of a specific tetrafluoroethylene-based polymer is mixed with a predetermined amount of a specific water-soluble solvent, and then mixed with a predetermined amount of an aqueous solution having a predetermined surface tension, the formation of coarse particles is suppressed.
• the inventors have found that an aqueous dispersion with excellent dispersion stability and foaming that is suppressed and easy to handle can be obtained.
• molded products such as polymer layers formed from such aqueous dispersions have excellent physical properties such as heat resistance and electrical properties (low coefficient of linear expansion, low dielectric constant, and low dielectric loss tangent) based on the tetrafluoroethylene polymer,
• heat resistance and electrical properties low coefficient of linear expansion, low dielectric constant, and low dielectric loss tangent
• the surface appearance is excellent, and the present invention was developed based on this discovery.
• An object of the present invention is to provide a method for producing an aqueous dispersion having excellent dispersion stability and ease of handling, and the aqueous dispersion.
• the present invention has the following aspects.
• 100 parts by mass of particles of a tetrafluoroethylene polymer having an average particle diameter of 1 ⁇ m or more and less than 10 ⁇ m are mixed with 5 to 20 parts by mass of a water-soluble solvent having a surface tension of 20 to 30 mN/m, and further the above-mentioned A method for producing an aqueous dispersion, which is mixed with 80 to 200 parts by mass of an aqueous solution whose surface tension has been adjusted to ⁇ 10 mN/m of the surface tension of a water-soluble solvent.
• the production method according to [1] wherein the tetrafluoroethylene polymer particles have a specific surface area of 1 to 25 m 2 /g.
• aqueous dispersion according to any one of [8] to [14] above is placed on the surface of a base material and heated to form a polymer layer containing the tetrafluoroethylene polymer,
• a method for producing a laminate comprising obtaining a laminate having a base material layer made of a material and the polymer layer in this order.
• an aqueous dispersion with excellent dispersion stability and handling properties can be obtained.
• Such an aqueous dispersion can be used to produce a coating layer, etc., which is based on a tetrafluoroethylene polymer and has excellent physical properties such as heat resistance and electrical properties (low coefficient of linear expansion, low dielectric constant, and low dielectric loss tangent), and particularly has excellent surface appearance. can be formed into molded objects.
• Average particle diameter (D50) is the volume-based cumulative 50% diameter of particles determined by laser diffraction/scattering method. That is, the particle size distribution is measured by a laser diffraction/scattering method, a cumulative curve is determined with the total volume of the particle population as 100%, and the particle diameter is the point on the cumulative curve where the cumulative volume becomes 50%.
• the D50 of the particles is determined by dispersing the particles in water and analyzing the particles using a laser diffraction/scattering method using a laser diffraction/scattering particle size distribution analyzer (LA-920 analyzer manufactured by Horiba, Ltd.).
• Average particle diameter (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 is a value calculated by measuring particles by gas adsorption (constant volume method) BET multi-point method, and is determined using NOVA4200e (manufactured by Quantachrome Instruments).
• Melting temperature is the temperature corresponding to the maximum value of the melting peak of the polymer as measured by differential scanning calorimetry (DSC).
• DSC differential scanning calorimetry
• Glass transition point (Tg)” is a value measured by analyzing a polymer using a dynamic mechanical analysis (DMA) method.
• Viscosity is determined by measuring the composition using a B-type viscometer at 25° C.
• the "thixotropic ratio” is a value calculated by dividing the viscosity ⁇ 1 of the composition measured at a rotation speed of 30 rpm by the viscosity ⁇ 2 measured at a rotation speed of 60 rpm. Each viscosity measurement was repeated three times, and the average value of the three measurements was taken.
• the "surface tension” of a solvent or solution is a value measured by the Wilhelmy method at 25° C. using a surface tension meter.
• a "unit" in a polymer means an atomic group based on the monomer formed by polymerization of the monomer.
• the unit may be a unit directly formed by a polymerization reaction, or may be a unit in which a part of said unit is converted into another structure by processing the polymer.
• a unit based on monomer a will also be simply referred to as a "monomer a unit.”
• the production method of the present invention (hereinafter also referred to as “this method”) is a method of manufacturing tetrafluoroethylene polymer (hereinafter also referred to as "F polymer”) having an average particle diameter of 1 ⁇ m or more and less than 10 ⁇ m (hereinafter referred to as " 100 parts by mass of F particles) and 5 to 20 parts by mass of a water-soluble solvent having a surface tension of 20 to 30 mN/m are mixed, and the surface tension is further adjusted to the surface tension of the water-soluble solvent ⁇ 10 mN/m.
• This is a method for producing an aqueous dispersion, in which the dispersion is mixed with 80 to 200 parts by mass of an aqueous solution prepared in the following manner.
• an aqueous dispersion with excellent dispersion stability and handling properties can be obtained.
• Molded products such as coating films (polymer layers) formed from such aqueous dispersions have physical properties such as heat resistance and electrical properties (low coefficient of linear expansion, low dielectric constant, and low dielectric loss tangent) based on the tetrafluoroethylene polymer. Excellent, especially its surface appearance.
• excellent surface appearance refers to excellent surface smoothness such as "less roughness on the surface", or visual recognition or analysis such as "no streaks, cracks, defects, etc. on the surface”. It includes any appearance that is excellent as observed by equipment.
• the reason why the aqueous dispersion obtained by this method has excellent dispersion stability, suppresses foaming, and is excellent in handling properties is not necessarily clear, but it is thought to be as follows.
• aqueous dispersion of F particles with an average particle diameter (D50) of 1 to 10 ⁇ m it is difficult to balance the wettability of the F particle surface and the cohesiveness of the F particles, and the Dispersion stability deteriorates due to formation, handling property deteriorates due to foam generation, and the coating film (polymer layer) formed from the aqueous dispersion tends to have poor appearance and defects.
• F particles with a D50 of 1-10 ⁇ m are premixed with a specific amount of a water-soluble solvent of a specific surface tension.
• 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 thermofusible or non-thermofusible.
• thermofusible polymer means a polymer that exists at a temperature at which the melt flow rate is 1 to 1000 g/10 minutes under a load of 49N.
• the melting temperature of the heat-melting 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.
• a molded article such as a coating film (polymer layer) formed from the aqueous dispersion obtained by this method 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.
• the surface tension of the F polymer is preferably 16 to 26 mN/m.
• the surface tension of F polymer can be measured by placing droplets of a wet tension test mixture (manufactured by Wako Pure Chemical Industries, Ltd.) specified in JIS K 6768 on a flat plate made of F polymer. .
• F polymers include polytetrafluoroethylene (PTFE), polymers containing TFE units and units based on ethylene (ETFE), polymers containing TFE units and units based on propylene, TFE units and perfluoro(alkyl vinyl ether) (PAVE) Polymers (PFA) containing units based on (PAVE units), polymers (FEP) containing TFE units and units based on hexafluoropropylene are preferred, PFA and FEP are more preferred, and PFA is even more preferred. These polymers may further contain units based on other comonomers.
• PTFE include low molecular weight PTFE and modified PTFE.
• the F polymer preferably has an oxygen-containing polar group, more preferably a hydroxyl group-containing group or a carbonyl group-containing group, and even more preferably a carbonyl group-containing group.
• the aqueous dispersion obtained by this method tends to have excellent dispersion stability and handling properties.
• molded products such as coating films (polymer layers) formed from such aqueous dispersions may have poor physical properties such as heat resistance, electrical properties (low coefficient of linear expansion, low dielectric constant, and low dielectric loss tangent), and their surface appearance. Easy to excel.
• the hydroxyl group-containing group is preferably a group containing an alcoholic hydroxyl group, more preferably -CF 2 CH 2 OH and -C(CF 3 ) 2 OH.
• Carbonyl group-containing groups include carboxyl group, alkoxycarbonyl group, amide group, isocyanate group, carbamate group (-OC(O)NH 2 ), acid anhydride residue (-C(O)OC(O)-), imide Residues (-C(O)NHC(O)-, etc.) and carbonate groups (-OC(O)O-) are preferred, and acid anhydride residues are more preferred.
• the number of oxygen-containing polar groups in the F polymer is preferably 10 to 5,000, more preferably 100 to 3,000 per 1 ⁇ 10 6 carbon atoms in the main chain. More specifically, the number of carbonyl group-containing groups in the F polymer is more preferably 50 or more, and even more preferably 100 or more per 1 ⁇ 10 6 carbon atoms in the main chain. Further, the number of carbonyl group-containing groups in the F polymer is preferably 3000 or less, more preferably 100 or less. In this case, the above-mentioned mechanism of action is more likely to be expressed to a higher degree.
• an F polymer that does not have an oxygen-containing polar group is an F polymer in which the number of oxygen-containing polar groups in the F polymer is less than 10 per 1 ⁇ 10 6 carbon atoms in the main chain. .
• 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 embodiment 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 the F polymer to plasma treatment or ionizing radiation treatment.
• the F polymer is preferably a polymer having carbonyl group-containing groups, including TFE units and PAVE units, and includes units based on monomers having TFE units, PAVE units and carbonyl group-containing groups, and for the total units: More preferably, the polymer contains 90 to 99 mol%, 0.99 to 9.97 mol%, and 0.01 to 3 mol% of these units in this order. Specific examples of such F polymers include the polymers described in International Publication No. 2018/16644.
• the monomer having a carbonyl group-containing group is preferably itaconic anhydride, citraconic anhydride, and 5-norbornene-2,3-dicarboxylic anhydride (hereinafter also referred to as "NAH"), and more preferably NAH.
• the D50 of the F particles is 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, more preferably 1.5 ⁇ m or more.
• D50 of the F particles is preferably 6 ⁇ m or less, more preferably 5 ⁇ m or less.
• the D90 of the F particles is preferably 8 ⁇ m or less, more preferably 6 ⁇ m or less.
• the specific surface area of the F particles is preferably 1 to 25 m 2 /g, more preferably 6 to 15 m 2 /g.
• the aqueous dispersion obtained by this method tends to have excellent dispersion stability and ease of handling.
• molded products such as coating films (polymer layers) formed from such aqueous dispersions may have poor physical properties such as heat resistance, electrical properties (low coefficient of linear expansion, low dielectric constant, and low dielectric loss tangent), and their surface appearance. Easy to excel.
• the F particles are particles containing F polymer, and are preferably composed of F polymer. More preferably, the F particles are particles of a heat-melting F polymer having an oxygen-containing polar group and having a melting temperature of 200 to 325°C. In this case, the above-mentioned mechanism of action is more fully expressed, and aggregation of F particles is more likely to be suppressed.
• the F particles may contain a resin or an inorganic compound other than the F polymer, or may form a core-shell structure in which the F polymer is the core and the shell is a resin or inorganic compound other than the F polymer.
• a core-shell structure may be formed in which the shell is made of a resin other than F polymer or an inorganic compound is made of a core.
• examples of the resin other than the F polymer include aromatic polyester, polyamideimide, polyimide, and maleimide
• examples of the inorganic compound include silica and boron nitride.
• the dispersibility of the aqueous dispersion obtained by this method is improved by balancing the agglomeration inhibiting effect of the heat-fusible F polymer particles with the retention effect of the fibrillation of the non-thermo-fusible tetrafluoroethylene polymer. Easy to improve.
• the electrical properties of the non-thermofusible tetrafluoroethylene polymer tend to be highly expressed.
• the nonionic surfactant so that the content of the nonionic surfactant is in the range of 1 to 15 parts by mass, and 3 to 10 parts by mass, based on 100 parts by mass of the aqueous dispersion obtained by this method. It is more preferable to use it within a range of 100%.
• the present dispersion has excellent coating properties and homogeneity, and can easily produce denser molded products. These liquid physical properties are likely to be improved when the present dispersion contains at least one nonionic water-soluble polymer selected from the group consisting of polyvinyl alcohol polymers, polyvinylpyrrolidone polymers, and polysaccharides.
• Example 2 Production example of aqueous dispersion
• 5 parts by mass of ethanol was added to 100 parts by mass of F particles 1, and the mixture was stirred at 2000 rpm using an autorotation and revolution stirrer (manufactured by Shinky Co., Ltd., product name "Awatori Rentaro (registered trademark) ARE-310"; the same applies hereinafter).
• the mixture was kneaded for 2 minutes to obtain a kneaded product.
• Foaming property of aqueous dispersion 50 ml of each dispersion was taken and placed in a 100 ml transparent container, and the transparent container was shaken up and down 10 times, and then left to stand for 10 minutes. The state of foaming after 10 minutes was visually confirmed and evaluated based on the following criteria. ⁇ Evaluation criteria> ⁇ : Foam is not confirmed ⁇ : Foam is confirmed, but it can be easily eliminated by anti-foam treatment ⁇ : Foam is observed, and it is difficult to eliminate foam by anti-foam treatment
• Example of manufacturing a laminate Dispersion 1 was applied to the surface of a long polyimide film (“FG-100” manufactured by PI Advanced Materials, thickness 25 ⁇ m) using a bar coater to form a liquid film.
• the polyimide film on which the liquid film was formed was passed through a drying oven at 120° C. for 5 minutes and dried by heating to obtain a dry film.
• the dry film was then heated at 380° C. for 3 minutes in a nitrogen oven.
• This treatment was also applied to the other surface of the polyimide film to produce a laminate 1 having a polyimide film and polymer layers (thickness: 12 ⁇ m) containing the fused and fired product of F particles 1 on both surfaces thereof.

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• Organic Chemistry (AREA)
• Dispersion Chemistry (AREA)
• Compositions Of Macromolecular Compounds (AREA)
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Citations (5)

• 2023
  • 2023-05-16 JP JP2024521951A patent/JPWO2023224050A1/ja active Pending
  • 2023-05-16 WO PCT/JP2023/018338 patent/WO2023224050A1/ja active Application Filing
  • 2023-05-18 TW TW112118521A patent/TW202406998A/zh unknown

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