JP6832816B2 - Composite particles for forming a water- and oil-repellent coating film, a method for producing the same, and a method for forming a water- and oil-repellent coating film using the composite particles. - Google Patents

Description

The present invention relates to composite particles for forming an oil-repellent coating film against salad oil, silicone oil, etc. with low surface tension while maintaining water repellency against water having high surface tension, a method for producing the same, and the composite particles. The present invention relates to a method for forming a coating film having water repellency and oil repellency (hereinafter, also referred to as water repellency and oil repellency).

Conventionally, as this type of coating film, a coating film formed on the surface of a material for imparting water repellency and oil repellency has been disclosed (see, for example, Patent Document 1). This coating film contains metal oxide composite particles, and the metal oxide composite particles include metal oxide particles and a coating layer containing a polyfluoroalkyl methacrylate resin formed on the surface of the metal oxide composite particles. The value obtained by dividing the fluorine content (% by weight) of the composite particles by the surface area (m ² / g) of the metal oxide particles is 0.025 to 0.180. In this coating film, the value obtained by dividing the carbon content (% by weight) of the metal oxide composite particles by the surface area (m ² / g) of the metal oxide particles is preferably 0.05 to 0.400. The average primary particle size of the metal oxide particles is preferably 5 to 50 nm, and the metal oxide particles are preferably at least one of silicon oxide particles, aluminum oxide particles, and titanium oxide particles. According to the coating film shown in Patent Document 1, the contact angle with water is 142 degrees or more and the contact angle with olive oil is 138 degrees or more, so that excellent water repellency and oil repellency can be obtained more reliably. it can.

Japanese Patent No. 5242841 (Table 2 of claims 1 to 4, paragraph [0012], paragraph [0103])

However, although the coating film described in Patent Document 1 exhibits oil repellency to olive oil, it may exhibit sufficient oil repellency to salad oil and silicone oil having a lower surface tension than olive oil. could not.

An object of the present invention is a composite particle for forming a water- and oil-repellent coating film, which has oil repellency against salad oil, silicone oil, etc., which has a low surface tension while maintaining water repellency against water having a high surface tension, a method for producing the same, and a composite thereof. It is an object of the present invention to provide a method for forming a water-repellent and oil-repellent coating film using particles.

The first aspect of the present invention is composed of a plurality of resin-coated particles in which a coating layer containing a fluoroalkyl acrylate resin or a fluoroacrylate resin is formed on the surface of inorganic particles having an average primary particle size of 5 to 100 nm. , The composite particles for forming a water-repellent oil-repellent coating film having a fluorine content of 1.5 to 7.5% by mass and a volume-based average particle size (D _{50) of 1 to 100 μm.}

The second aspect of the present invention is an invention based on the first aspect, which is a composite particle having a carbon content of 2.0 to 10.0% by mass of the composite particle.

The third aspect of the present invention is an invention based on the first or second aspect, and the inorganic particles are selected from the group consisting of oxides, hydroxides, fluorides, nitrides and composite oxides. It is a composite particle which is one kind or two or more kinds of particles.

A fourth aspect of the present invention is an invention based on the third aspect, which is a composite particle in which the inorganic particles are dry particles.

A fifth aspect of the present invention is to put inorganic particles having an average primary particle size of 5 to 100 nm into a reaction vessel, and to stir the inorganic particles in the reaction vessel under an inert gas atmosphere while using a fluoroalkyl acrylate resin or A liquid containing a fluoroacrylate resin is sprayed from 30 to 220 ° C. at a temperature of 150 to 220 ° C. while spraying so that the amount of the resin component is 7.5 to 25.0 parts by mass with respect to 100 parts by mass of the inorganic particles. The surface of the inorganic particles is heat-treated for 120 minutes to form resin-coated particles by coating the surface of the inorganic particles with a fluoroalkyl acrylate resin layer or a fluoroacrylate resin layer, and the resin-coated particles are aggregated to form any of the first to fourth particles. This is a method for producing composite particles for forming a water-repellent and oil-repellent coating film from this viewpoint.

The sixth aspect of the present invention is the water-repellent oil-repellent coating film-forming composite particles of any one of the first to fourth aspects or the water-repellent oil-repellent coating film-forming composite produced by the method of the fifth aspect. The composite particles are dispersed in a solvent at a ratio of 10 to 20% by mass with respect to 100% by mass of the solvent to prepare a dispersion liquid, and the dispersion liquid is applied to the surface of the substrate to apply a water-repellent oil-repellent coating. It is a method of forming a film.

The seventh aspect of the present invention is the invention based on the sixth aspect, in which the contact angle of water with respect to the formed water-repellent oil-repellent coating film is 110 degrees or more at 25 ° C., and the contact angle of salad oil is 25. This is a method for forming a water- and oil-repellent coating film having a contact angle of silicone oil of 120 degrees or more at ° C. and 60 degrees or more at 25 ° C.

In the invention based on the first aspect of the present invention, inorganic particles having an average primary particle diameter of 5 to 100 nm are coated with a coating layer containing a fluoroalkyl acrylate resin or a fluoroacrylate resin to form resin-coated particles. As shown in FIG. 1A, an uneven structure having an interval of several nm to several tens of nm is formed on the surface of a single composite particle in which resin-coated particles are aggregated because the average primary particle size of the inorganic particles is 5 to 100 nm. Approximate fractal structure) is formed. Further, in a state where single composite particles having an average particle size (D ₅₀ ) of 1 to 100 μm are lined up in a row, as shown in FIG. 1 (b), there is an uneven structure (approximate) between the composite particles at intervals of several tens of μm. Fractal structure) is formed. Such a hierarchical uneven structure physically causes the composite particles to exhibit water and oil repellency. On the other hand, since the inorganic particles are coated with a fluoroalkyl acrylate resin or a fluoroacrylate resin different from the polyfluoroalkyl methacrylate resin shown in Patent Document 1, the composite particles are chemically exhibited to have water and oil repellency.

In the fluoroalkyl acrylate resin or fluoroacrylate resin of the present invention, the acrylate promotes the generation of (1) free radicals (free radicals) and (2) the chemical structural formula as compared with the methyl group of methacrylate in Patent Document 1. The connection part is easy to rotate and the molecular motility is increased. Due to these effects, fluoroalkyl groups (hereinafter, also referred to as Rf groups) having a high ability to reduce surface tension are bonded to the surface of finer inorganic particles with high adhesion to form a coating layer that coats the inorganic particles. To do. The fluorine content of the composite particles may be within a predetermined range, and as a result, the coating film formed of the dispersion liquid containing the composite particles repels liquids such as salad oil and silicone oil, which have a lower surface tension than olive oil. Can be done. Further, by setting the average particle size (D ₅₀ ) of the composite particles within a predetermined range, in addition to the above physical effects, the coating film formed of the dispersion liquid containing the composite particles becomes uniform with a desired thickness. , Exhibits excellent water and oil repellency.

In the invention based on the second aspect of the present invention, by setting the carbon content of the composite particles within a predetermined range, the coating film formed of the dispersion liquid containing the composite particles exhibits more excellent water and oil repellency. ..

In the invention based on the third aspect of the present invention, even when particles such as hydroxide, fluoride, nitride, and composite oxide are used as the inorganic particles in addition to oxide particles such as silica, the composite is used. A coating film formed of a dispersion liquid containing particles exhibits excellent water and oil repellency.

In the invention based on the fourth aspect of the present invention, when the inorganic particles are dry particles, the composite particles in which the dry particles are aggregated exhibit more excellent water and oil repellency.

In the invention based on the fifth aspect of the present invention, the resin component is determined with respect to 100 parts by mass of the inorganic particles in a liquid containing a fluoroalkyl acrylate resin or a fluoroacrylate resin while stirring the inorganic particles in an inert gas atmosphere. By heat-treating while spraying so as to have the spray amount of, the surface of the inorganic particles is uniformly coated with the fluoroalkyl acrylate resin layer or the fluoroacrylate resin layer with a predetermined thickness, and the resin-coated particles are formed. Further, the resin-coated particles can be aggregated by stirring to produce composite particles.

In the invention based on the sixth aspect of the present invention, the composite particles of the present invention are dispersed in a solvent at a predetermined ratio to prepare a dispersion liquid, and the dispersion liquid is applied to the surface of the substrate to obtain water and oil repellency. An excellent coating film can be formed.

In the invention based on the seventh aspect of the present invention, the contact angle of water with respect to the formed coating film is 110 degrees or more at 25 ° C, the contact angle of salad oil is 120 degrees or more at 25 ° C, and the contact angle of silicone oil is 25. Since the temperature is 60 ° C. or higher, it exhibits excellent water and oil repellency even for oils with low surface tension.

It is a schematic diagram of the composite particle for forming a water-repellent oil-repellent coating film of the embodiment of this invention. 1 (a) is a schematic diagram of a single composite particle, FIG. 1 (b) is a schematic diagram of a state in which a plurality of composite particles are arranged in a row, and FIG. 1 (c) is a schematic diagram of a plurality of composite particles arranged in a row. It is a schematic diagram which shows the hierarchical uneven structure of the composite particle of. It is a photographic figure which shows the oil-repellent property of the silicone oil on the coating film surface using the composite particle of Example 6 by the contact angle. It is a photographic figure which shows the oil-repellent property of the silicone oil on the coating film surface using the composite particle of the comparative example 2 by the contact angle. It is a photographic figure of 3,000 times magnification which observed the composite particle of Example 3 by SEM. It is a photographic figure of 3,000 times magnification observed by SEM of the particles made of only the fluoroalkyl acrylate resin of Comparative Example 10. It is a photographic figure which shows the water repellency of water on the coating film surface using the composite particles of Examples 1-8, and the oil repellency of salad oil and silicone oil by the contact angle.

Next, a mode for carrying out the present invention will be described.

[Inorganic particles]
The inorganic particles constituting the water- and oil-repellent coating film-forming composite particles of the present invention have an average primary particle diameter of 5 to 100 nm, preferably 10 to 50 nm, and more preferably 12 to 30 nm. When the average primary particle diameter is less than the lower limit of 5 nm, the surface of the composite particle does not have an uneven structure (approximate fractal structure) when the composite particle is produced from the inorganic particle, and the surface of the composite particle becomes There is a problem that it does not become water- and oil-repellent, and if it exceeds the upper limit of 100 nm, the space distance between adjacent composite particles becomes too large, and it becomes difficult to obtain an approximate fractal structure due to the composite particles, resulting in water- and oil-repellent properties. Problems that are difficult to demonstrate occur. The average primary particle size of the inorganic particles is 50,000 times larger than that of the inorganic particles using a general scanning electron microscope (for example, model name: JSM-7001F manufactured by JEOL Ltd.). It is a value obtained by randomly measuring 50 or more particle diameters of the inorganic particles inside and calculating the average thereof. It is preferable that the inorganic particles are aggregated particles because they form an approximate fractal structure.

Examples of these inorganic particles are one or more particles selected from the group consisting of oxides, hydroxides, fluorides, nitrides and composite oxides. Specifically, these particles include silica, titania, alumina, calcium oxide, zinc oxide, zinc oxide, magnesium fluoride, natural smectite, synthetic smectite, vermiculite, tin-doped indium oxide (ITO), and antimony-doped tin oxide (ITO). Examples thereof include tin oxide, indium oxide, cadmium oxide, antimony oxide, aluminum hydroxide, calcium fluoride, magnesium fluoride, aluminum nitride, boron nitride, and composite oxides of silica and titania. Further, the inorganic particles are preferably dry particles. Dry particles are particles produced by the vapor phase method. Among these, dry silica particles, dry titania particles, and dry alumina particles are preferable. The dry silica particles are silica produced by vapor phase oxidation of a silicon halogen compound, and are produced by burning a silicon compound such as silicon tetrachloride or metallic silicon in a flame, for example, an acid hydrogen flame (spraying). Fumed silica (produced by the flame method) is preferable because it does not use a solvent and does not generate agglomerated particles when dried.

[Coating layer containing fluoro (alkyl) acrylate resin]
The coating layer formed on the surface of the inorganic particles constituting the water- and oil-repellent coating film-forming composite particles of the present invention contains a fluoro (alkyl) acrylate resin, that is, a fluoroalkyl acrylate resin or a fluoroacrylate resin. A feature of the present invention is that the coating layer is a fluoroalkyl acrylate resin or a fluoroacrylate resin different from the polyfluoroalkyl methacrylate resin shown in Patent Document 1. By changing the "methacrylate" of Patent Document 1 to the "acrylate" of the present invention, as described above, (1) the generation of free radicals (free radicals) is promoted, and (2) the bond portion in the chemical structural formula is promoted. It is easy to rotate and the molecular mobility is high. From these effects, the Rf group having a high ability to reduce the surface tension is bonded to the surface of the finer inorganic particles with a high adhesive force to form a coating layer for coating the inorganic particles. The coating film formed of the dispersion liquid containing the inorganic particles and the composite particles in which the resin coating particles having the coating layer are aggregated can repel liquids such as salad oil and silicone oil having a surface tension lower than that of olive oil. A dispersion liquid containing composite particles having a polyfluoroalkyl methacrylate resin as a coating layer shown in Patent Document 1 and a dispersion liquid containing composite particles having a (poly) fluoroalkyl acrylate resin as a coating layer of the present invention, respectively, glass. Table 1 below shows a comparison of the contact angles between the coating film on the glass plate and each droplet when applied to the plate.

Examples of the fluoroalkyl acrylate resin or fluoroacrylate resin include ethyl 2-fluoroacrylate, phenyl2-fluoroacrylate, 3-fluoropropyl acrylate, 2.2-difluoroethyl acrylate, methyl 3.3-difluoroacrylate, and 2-fluoroethyl acrylate. , Methyl 2-fluoroacrylate, 1H, 1H-perfluorononyl acrylate, methyl 2,3,3-trifluoroacrylate, pentafluorobenzyl acrylate, pentafluorophenyl acrylate, tert-butyl 2-fluoroacrylate, methyl 2-fluoroacrylate , Hexafluoroisopropyl acrylate, methyl 3- (4-fluorophenyl) acrylate, 3- (trifluoromethyl) benzyl acrylate, 1H, 1H-perfluorooctyl acrylate, 2,2,2-trifluoroethyl acrylate, heptafluoroisopropyl Acrylate, 2- (perfluorobutyl) ethyl acrylate, hexafluorobisphenol A diacrylate, 1H, 1H-pentafluoropropyl acrylate, 2,2,2-trifluoroethyl-2-fluoroacrylate, methyl 3- (2,4) -Difluorophenyl) acrylate, ethyl (2E) -3- (4-fluorophenyl) acrylate, 2,2,2-trichloroethyl-2-fluoroacrylate, 1H, 1H-pentafluorobutyl-2-fluoroacrylate, methyl 2 -(Trifluoromethyl) acrylate, 2,2,3,3-tetrafluoropropyl acrylate, tert-butyl 2- (trifluoromethyl) acrylate, (E) -methyl 3- (2,5-difluorophenyl) acrylate, Examples thereof include (E) -methyl 3- (3,5-difluorophenyl) acrylate, 1H, 1H, 7H-dodecafluorophenyl acrylate, 2,2,3,4,4,4-hexafluorobutyl acrylate and the like. Further, as commercially available products of fluoroalkyl acrylate or fluoroacrylate, for example, product names "CHEMINOX FAAC-4", "CHEMINOX FAAC-6" (all manufactured by Unimatec), product names "TG-8111", "TG-8731". , "GMW-605" (above, manufactured by Daikin Industries, Ltd.), product names "CB71445188", "CB51457934", "CB3449325" (above, manufactured by Maya High Purity Chemicals), "AB279005", "AB3558507", "AB35857" , "AB103903" (above, manufactured by Abcr GmbH & Co., KG), "474487", "474347", "474355", "474428", "470961", "474452", "474401", "443751" (above, Sigma) -Aldrich), "ADE000791", "ADE000110", "ADE001060", "553867", "689385" (all manufactured by Sigma-RBI) and the like. The fluoroalkyl acrylate resin or the fluoroalkyl acrylate or fluoroacrylate of the fluoroacrylate resin of the present invention is not limited to the monomer, but also includes a polymer.

[Composite particles for forming water- and oil-repellent coating films]
As shown in FIG. 1A, the water- and oil-repellent coating film-forming composite particles 10 of the present invention are resins in which a coating layer 12 containing a fluoroalkyl acrylate resin or a fluoroacrylate resin is formed on the surface of the inorganic particles 11. A plurality of coated particles 13 are aggregated and formed. The volume-based average particle size (D 50) of the composite particles is 1 to 100 _{μm, preferably 5 to 20 μm.} The volume-based average particle size (D ₅₀ ) of a composite particle is measured by a general laser diffraction / scattering type particle size distribution measuring device (for example, LA series (model number: LA-920) manufactured by HORIBA, Ltd.). Since the average primary particle size of the above-mentioned inorganic particles is 5 to 100 nm, as shown in FIG. 1 (a), the surface of the composite particle has an uneven structure (approximate fractal structure) of several nm to several tens of nm. Is formed. Further, since the average particle size (D ₅₀ ) of the composite particles is 1 to 100 μm, as shown in FIG. 1 (b), the composite particles are in a state where a plurality of composite particles 10, 10, ... Are arranged in a row. A space of several tens of μm is formed between them, and as shown in FIG. 1C, the uneven structure of the surfaces of the plurality of composite particles arranged side by side becomes hierarchical, and the surfaces of these composite particles exhibit water and oil repellency. become. If the average particle size (D ₅₀ ) of the composite particles is less than 1 μm or exceeds 100 μm, an uneven structure (approximate fractal structure) is not formed on the surface of the composite particles.

The fluorine content of the composite particles is 1.5 to 7.5% by mass, preferably 3.0 to 7.5% by mass, and more preferably 3.0 to 6.0% by mass with respect to 100% by mass of the composite particles. %. The carbon content of the composite particles is 2.0 to 10.0% by mass, preferably 4.0 to 8.0% by mass, and more preferably 3.5 to 6.0% by mass with respect to 100% by mass of the composite particles. %. If the fluorine content is less than 1.5% by mass, the desired water and oil repellency cannot be obtained. Further, when the carbon content is less than 2.0% by mass, it is difficult to coat the surface of the composite particle with a sufficient fluororesin component, and it is difficult to exhibit the water- and oil-repellent function. Furthermore, the reason why the upper limit of the fluorine content is set to 7.5% by mass is that the water- and oil-repellent function of the composite particles does not change even if it exceeds 7.5% by mass, and excessive use of fluororesin is avoided. Is. If the carbon content exceeds 10.0% by mass, there is a risk of dust explosion due to the excessive carbon content contained in the composite particle powder. In the present invention, the fluorine content is set within a predetermined range in order to achieve excellent water and oil repellency, and the carbon content is also within a predetermined range in order to achieve even better water and oil repellency. It is preferable to set it. These predetermined ranges depend on the amount of fluoroalkyl acrylate resin or fluoroacrylate resin that coats the surface of the inorganic particles.

For the fluorine content in the composite particles of the present invention, a sample of the composite particles is fired in an electric furnace at 1000 ° C., the generated gas is recovered by steam distillation, and the recovered liquid is detected as fluorine ions by an ion chromatograph. , Obtained by quantification. The carbon content in the composite particles of the present invention is a carbon component obtained by extracting the composite particles with an organic solvent. Specifically, this carbon content is measured as follows using a general carbon analyzer (for example, manufactured by SUMIGARPH NC-22 Sumika Chemical Analysis Service, Inc.). Set the standard sample that has been weighed and the board containing the measurement sample in the device, and start the measurement. The measurement data processing program automatically calculates the final result. Evaluate the automatically calculated carbon content at that time. When measuring the amount of carbon, a sample that has been surface-treated in advance is measured with a sample that has undergone Soxhlet extraction. In Soxhlet extraction, the solvent used for extraction is distilled every time it is heated, and it is received at the part where the sample is placed. As the amount of distilled solvent increases, all the solvent accumulated in excess of the required amount according to the siphon principle is before distillation. It is an operation to extract from the sample while returning to the flask.

[Manufacturing method of composite particles for forming water- and oil-repellent coating films]
In the composite particles for forming a water- and oil-repellent coating film of the present invention, the above-mentioned inorganic particles are placed in a reaction vessel, and the inorganic particles are subjected to an inert gas (non-oxidizing) such as nitrogen gas and argon gas in the reaction vessel. While stirring in an atmosphere, spray the fluoroalkyl acrylate resin or the liquid containing the fluoroacrylate resin in an amount of 7.5 to 25.0 parts by mass, preferably 10.0 to 15 parts by mass of the resin component with respect to 100 parts by mass of the inorganic particles. The surface of the inorganic particles is treated with a fluoroalkyl acrylate resin at a temperature of 150 to 220 ° C., preferably 180 to 200 ° C. for 30 to 120 minutes, preferably 60 to 90 minutes while spraying so as to be 0.0 parts by mass. It is produced by forming resin-coated particles by coating with a layer or a fluoroacrylate resin layer and aggregating the resin-coated particles. Alternatively, it is produced by mixing the above fluoroalkyl acrylate resin or fluoroacrylate resin with inorganic particles and drying the solvent. It is preferably produced by drying at a temperature of 150 to 220 ° C., preferably 180 to 200 ° C. while flowing.

The liquid containing the fluoroalkyl acrylate resin or the fluoroacrylate resin contains 10 to 25% by mass of the liquid component with respect to 100% by mass of the liquid containing the resin. Water is preferably used as the liquid component. If the liquid component is less than the lower limit, the concentration of the liquid containing the resin is too high, and it is difficult to form a uniform resin layer on the surface of the inorganic particles. If the liquid component exceeds the upper limit, the concentration of the liquid containing the resin is too low. It is necessary to increase the amount of spray. The temperature and time of the heat treatment are determined according to the content ratio of the liquid component, but when the heat treatment temperature is less than 180 ° C. or the heat treatment time is less than 30 minutes, almost no resin layer is formed on the surface of the inorganic particles, and the heat treatment is performed. If the temperature exceeds 220 ° C. or the heat treatment time exceeds 120 minutes, the resin layer becomes too thick, and in either case, water- and oil-repellent composite particles cannot be obtained.

The spraying amount of the fluoroalkyl acrylate resin or the liquid containing the fluoroacrylate resin is such that the spray amount is 7.5 to 25.0 parts by mass with respect to 100 parts by mass of the inorganic particles. If it is less than 5.5 parts by mass, the thickness of the coating layer becomes insufficient, the fluorine content and carbon content in the coating layer are low, and the water and oil repellency is not exhibited. When the amount of spray exceeds 25.0 parts by mass, the fluororesin component covered on the surface of the composite particles becomes excessive, and the fractal structure formed by the fine particles is offset by the resin (the surface becomes smoother and thinner). There is a risk that it will not exhibit high oil repellency.

When the liquid containing the resin is sprayed and heat-treated while stirring the inorganic particles, the liquid components in the liquid containing the resin evaporate, and a coating layer containing the polyfluoroacrylate resin or the fluoroacrylate resin is formed on the surface of the inorganic particles. To. Further, for example, a series of steps including a spraying step and a heat treatment step may be repeated once or twice or more, if necessary. Thereby, the thickness of the coating amount is controlled, and the fluorine content and the carbon content can be adjusted within desired ranges.

[Method of forming water- and oil-repellent coating film]
The water- and oil-repellent coating film of the present invention prepares a dispersion liquid by dispersing the above-mentioned composite particles in a solvent at a ratio of 10 to 20% by mass of the composite particles with respect to 100% by mass of the solvent. Is formed by applying to the surface of the substrate. This dispersion may contain an adhesive (heat sealant or the like), a colorant, a dispersant, a settling inhibitor, a viscosity modifier, a print protective agent, or the like. Examples of the solvent include water and alcohol when an adhesive or the like is not contained. As the alcohol, one kind or two or more kinds of alcohols having 1 to 4 carbon atoms are preferable. When an adhesive or the like is contained, the solvent may be alcohol (ethanol), cyclohexane, toluene, acetone, IPA, propylene glycol, hexylene glycol, butyl diglycol, pentamethylene glycol, normal pentane, normal hexane, hexyl alcohol or the like. An organic solvent is used.

Examples of the adhesive include adhesives (particularly heat sealants) such as polyolefin resins, polyester resins, polyurethane resins, epoxy resins, acrylic resins, and vinyl resins. More specifically, the heat sealant includes low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear (linear) low-density polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ionoma-resin, and ethylene. -Acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-propylene copolymer, methylpentene polymer, polybutene polymer, polyethylene Alternatively, an acid-modified polyolefin resin, polyvinyl acetate resin, poly (poly), which is obtained by modifying a polyolefin resin such as polypropylene with an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, or itaconic acid. Meta) Acrylic resin, polyacrylonitrile resin, polyvinyl chloride resin, other heat-adhesive resins, blended resins of these, copolymers containing combinations of monomers constituting these, modified resins, etc. are heat-sealed agents. Can be used as.

Examples of the base material include metal materials, plastic materials, ceramic materials, glass materials, surface-processed wood, and processed paper that require water- and oil-repellent treatment. After applying the dispersion liquid applied to the surface of the base material, when the solvent is water or alcohol, it is left at room temperature and naturally dried to form a water- and oil-repellent coating film on the surface of the base material. When the dispersion liquid contains a heat sealant as an adhesive component, the heat sealant is melted by heat-treating the coating film on the surface of the base material in the range of about 150 to 250 ° C. to strengthen the coating film on the material surface. Can be fixed to.

The dispersion liquid can be applied to the surface of the base material and naturally dried, or dried at a predetermined temperature and then heat-treated to form a coating film on the surface of the base material. Examples of the method of applying the dispersion liquid to the surface of the base material include a bar coating method, a die coating method, a spin coating method or a spray method, and a doctor blade method. The thickness of the coating film is determined in the range of 0.5 to 30 μm. In particular, when the packaging material is configured such that the coating film is embedded in the heat seal layer during heat sealing, the thickness is preferably about 1 to 8 μm.

[Characteristics of water- and oil-repellent coating film]
The water- and oil-repellent coating film of the present invention preferably has an uneven structure (approximate fractal structure) with composite particles on the surface of the coating film. More specifically, it is desirable to have voids formed by connecting a plurality of composite particles and a surface formed by the particle body. This makes it possible to exhibit more excellent water repellency and oil repellency in combination with the composite particles having a predetermined coating layer. That is, as a result that the surface of the uneven structure is substantially formed by the coating layer, more excellent water repellency and oil repellency can be exhibited. In this case, the particles that contribute to the formation of the uneven structure may include fine particles other than composite particles as long as the effects of the present invention are not impaired. The uneven structure on the surface of the coating film can be observed with a scanning electron microscope. Example 3 described later is shown in FIG. 4 as a representative example.

The water and oil repellency of the coating film formed by the above method is indicated by the contact angle of water, salad oil, and silicone oil at 25 ° C. with respect to the coating film. The water and oil repellency of the coating film of the present invention is such that the contact angle of water is 110 degrees or more at 25 ° C, the contact angle of salad oil is 120 degrees or more at 25 ° C, and the contact angle of silicone oil is 60 degrees or more at 25 ° C. ..

Next, examples of the present invention will be described in detail together with comparative examples.

[20 types of resin]
A total of 20 types of resins used in Examples 1 to 15 and Comparative Examples 1 to 12 of the present invention are shown in Tables 2 and 3 below. Table 2 shows 14 types of (poly) fluoro (alkyl) acrylate resins (No. 1 to No. 14), and Table 3 shows 6 types of (poly) fluoroalkyl methacrylate resins (No. 21 to No. 14). 26) are shown respectively.

<Example 1>
As the inorganic particles, fumed silica (Japan), which is a dry silica having an average primary particle diameter (hereinafter, the same applies to the method for measuring the average primary particle diameter) determined by using the scanning electron microscope illustrated above, is 80 to 100 nm. Using Aerodil Co., Ltd .: prototype), this was placed in a reaction vessel, and the No. 1 fluoroalkyl acrylate resin shown in Table 2 was dispersed in water with respect to 100 g of the silica particles while stirring in a nitrogen gas atmosphere. 37.5 g of the liquid (liquid component concentration: 20% by mass) was sprayed, heated and stirred at 200 ° C. for 30 minutes, and then cooled to room temperature to prepare composite particles in which resin-coated particles were aggregated. The spray amount of the resin component was 7.5 parts by mass with respect to 100 parts by mass of the silica particles. The amount of the resin component sprayed after Example 2 is shown in Table 4.

<Example 2>
As the inorganic particles, fumed silica (trade name: AEROSIL OX 50, manufactured by Nippon Aerosil Co., Ltd.), which is a dry silica having an average primary particle diameter of 40 nm, is used, placed in a reaction vessel, and stirred in a nitrogen gas atmosphere. 50 g (liquid component concentration: 20% by mass) of the aqueous dispersion of No. 2 fluoroalkyl acrylate resin shown in Table 2 is sprayed on 100 g of the silica particles, heated and stirred at 150 ° C. for 60 minutes, and then brought to room temperature. The particles were cooled to prepare composite particles in which the resin-coated particles were aggregated.

<Example 3>
Using the same dry silica as in Example 1 as the inorganic particles, this was placed in a reaction vessel, and the No. 3 polyfluoroalkyl shown in Table 2 was added to 100 g of the silica particles while stirring under a nitrogen gas atmosphere. 60 g (liquid component concentration: 20% by mass) of an aqueous dispersion of an acrylate resin was sprayed, and composite particles were prepared in the same manner as in Example 1 below. FIG. 4 shows a photograph of the composite particles of Example 3 observed by SEM at a magnification of 3,000.

<Example 4>
As the inorganic particles, fumed silica (trade name: AEROSIL 200, manufactured by Nippon Aerosil Co., Ltd.), which is a dry silica having an average primary particle diameter of 12 nm, is used, placed in a reaction vessel, and this is stirred in a nitrogen gas atmosphere. Water of a mixed resin of No. 4 polyfluoroalkyl acrylate resin and No. 6 polyfluoroacrylate resin (No. 4: No. 6 mass ratio = 2: 1) shown in Table 2 with respect to 100 g of silica particles. 75 g of the dispersion liquid (liquid component concentration: 20% by mass) was sprayed to prepare composite particles in the same manner as in Example 1.

<Example 5>
As the inorganic particles, fumed silica (trade name: AEROSIL 380 S, manufactured by Nippon Aerosil Co., Ltd.), which is a dry silica having an average primary particle diameter of 5 nm, is used, placed in a reaction vessel, and stirred in a nitrogen gas atmosphere. A mixed resin of No. 5 polyfluoroalkyl acrylate resin and No. 7 fluoroalkyl acrylate resin (No. 5: No. 7 mass ratio = 2: 1) shown in Table 2 with respect to 100 g of the silica particles. 100 g of the aqueous dispersion (liquid component concentration: 20% by mass) was sprayed to prepare composite particles in the same manner as in Example 1.

<Example 6>
As the inorganic particles, fumed silica (trade name: AEROSIL 50, manufactured by Nippon Aerosil Co., Ltd.), which is a dry silica having an average primary particle diameter of 30 nm, is used, placed in a reaction vessel, and this is stirred in a nitrogen gas atmosphere. Water dispersion of mixed resin of No. 6 polyfluoroacrylate resin and No. 9 fluoroalkyl acrylate resin (No. 6: mass ratio of No. 9 = 1: 1) shown in Table 2 with respect to 100 g of silica particles. 125 g of the liquid (liquid component concentration: 20% by mass) was sprayed to prepare composite particles in the same manner as in Example 1.

<Example 7>
Using the same dry silica as in Example 1 as the inorganic particles, this was placed in a reaction vessel, and the No. 4 polyfluoroalkyl shown in Table 2 was added to 100 g of the silica particles while stirring under a nitrogen gas atmosphere. 60 g (liquid component concentration: 20% by mass) of an aqueous dispersion of an acrylate resin was sprayed, and composite particles were prepared in the same manner as in Example 1 below.

<Example 8>
As the inorganic particles, dry alumina (trade name: AEROXIDE Alu 65, manufactured by Nippon Aerodil Co., Ltd.) having an average primary particle diameter of 20 nm was used, and this was placed in a reaction vessel, and the alumina particles were made into 100 g of these alumina particles while stirring in a nitrogen gas atmosphere. On the other hand, 60 g of an aqueous dispersion of a mixed resin of No. 9 fluoroacrylate resin and No. 12 fluoroalkyl acrylate resin (No. 9: No. 12 mass ratio = 1: 1) shown in Table 2 (liquid component). Concentration: 20% by mass) was sprayed to prepare composite particles in the same manner as in Example 1.

<Example 9>
As the inorganic particles, dry titania (trade name: AEROXIDE P 25, manufactured by Nippon Aerodil Co., Ltd.) having an average primary particle diameter of 20 nm was used, and this was placed in a reaction vessel, and the titania particles were made into 100 g of the titania particles while stirring in a nitrogen gas atmosphere. On the other hand, 60 g of an aqueous dispersion of a mixed resin of No. 11 fluoroalkyl acrylate resin and No. 14 fluoroalkyl acrylate resin (No. 11: No. 14 mass ratio = 1: 1) shown in Table 2 (liquid). (Component concentration: 20% by mass) was sprayed to prepare composite particles in the same manner as in Example 1.

<Example 10>
Wet silica (manufactured by Nippon Aerosil Co., Ltd .: prototype) made by the sol-gel method with an average primary particle diameter of 100 nm was used as the inorganic particles, placed in a reaction vessel, and this sol-gel silica was stirred under a nitrogen gas atmosphere. 30 g (liquid component concentration: 25% by mass) of the aqueous dispersion of No. 5 fluoroalkyl acrylate resin shown in Table 2 was sprayed on 100 g of the particles, and the composite particles were subsequently prepared in the same manner as in Example 1. Made.

<Example 11>
As the inorganic particles, aluminum hydroxide having an average primary particle diameter of 30 nm was used, placed in a reaction vessel, and the No. 1 shown in Table 2 was applied to 100 g of the aluminum hydroxide particles while stirring in a nitrogen gas atmosphere. Spray 125 g of an aqueous dispersion of a mixed resin of the polyfluoroacrylate resin of No. 6 and the fluoroalkyl acrylate resin of No. 9 (No. 6: mass ratio of No. 9 = 1: 1), and the same as in Example 1 below. To prepare composite particles.

<Example 12>
As the inorganic particles, calcium fluoride having an average primary particle diameter of 15 to 40 nm is used, placed in a reaction vessel, and shown in Table 2 with respect to 100 g of the calcium fluoride particles while stirring in a nitrogen gas atmosphere. 60 g of an aqueous dispersion of a mixed resin of No. 9 fluoroacrylate resin and No. 12 fluoroalkyl acrylate resin (No. 9: No. 12 mass ratio = 1: 1) was sprayed, and the following is described in Example 1 and In the same manner, composite particles were prepared.

<Example 13>
Magnesium fluoride having an average primary particle diameter of 5 nm was used as the inorganic particles, and the particles were placed in a reaction vessel, and the No. 1 shown in Table 2 was applied to 100 g of the magnesium fluoride particles while stirring in a nitrogen gas atmosphere. Spray 100 g of an aqueous dispersion of a mixed resin of the polyfluoroalkyl acrylate resin of No. 5 and the fluoroalkyl acrylate resin of No. 7 (No. 5: No. 7 mass ratio = 2: 1), and the following with Example 1 In the same manner, composite particles were prepared.

<Example 14>
Boron nitride particles having an average primary particle diameter of 100 nm were used as the inorganic particles, placed in a reaction vessel, and stirred in a nitrogen gas atmosphere with respect to 100 g of the boron nitride particles, No. 1 shown in Table 2. 37.5 g (liquid component concentration: 20% by mass) of the aqueous dispersion of the fluoroalkyl acrylate resin of No. 1 was sprayed, and the composite particles were prepared in the same manner as in Example 1 below.

<Example 15>
As inorganic particles, a composite oxide of silica and titania with an average primary particle size of 20 to 30 nm (manufactured by Nippon Aerosil Co., Ltd .: prototype) is used, placed in a reaction vessel, and this silica / silica is stirred in a nitrogen gas atmosphere. 50 g (liquid component concentration: 20% by mass) of the aqueous dispersion of No. 2 fluoroalkyl acrylate resin shown in Table 2 was sprayed onto 100 g of the titania composite oxide particles, and the same applies hereinafter to Example 2. , Composite particles were prepared.

<Comparative example 1>
As the inorganic particles, the same dry silica as in Example 1 was used, and this was placed in a reaction vessel. Under a nitrogen gas atmosphere, 100 g of the silica particles were stirred and the same No. 2 shown in Table 2 as in Example 1 was used. 37.5 g (liquid component concentration: 20% by mass) of an aqueous dispersion of the fluoroalkyl acrylate resin of .1 was sprayed to prepare composite particles in the same manner as in Example 1.

<Comparative example 2>
As the inorganic particles, the same dry silica as in Example 1 was used, and the particles were placed in a reaction vessel, and while stirring under a nitrogen gas atmosphere, 100 g of the silica particles were shown in Table 3 as shown in Patent Document 1. 37.5 g (liquid component concentration: 20% by mass) of the indicated aqueous dispersion of fluoroalkyl methacrylate of No. 22 was sprayed, and composite particles were prepared in the same manner as in Example 1 below.

<Comparative example 3>
As the inorganic particles, the same dry silica as in Example 2 was used, and the particles were placed in a reaction vessel, and while stirring under a nitrogen gas atmosphere, 100 g of the silica particles were shown in Table 3 as shown in Patent Document 1. 50 g (liquid component concentration: 20% by mass) of the indicated aqueous dispersion of polyfluoroalkyl methacrylate of No. 23 was sprayed, and hereinafter, composite particles were prepared in the same manner as in Example 1.

<Comparative example 4>
As the inorganic particles, the same dry silica as in Example 1 was used, and the particles were placed in a reaction vessel, and while stirring under a nitrogen gas atmosphere, 100 g of the silica particles were shown in Table 3 as shown in Patent Document 1. 60 g of an aqueous dispersion of a mixed resin of No. 21 fluoroalkyl methacrylate resin and No. 24 polyfluoroalkyl methacrylate resin (No. 21: No. 24 mass ratio = 1: 1) (liquid component concentration: 20). Mass%) was sprayed to prepare composite particles in the same manner as in Example 1.

<Comparative example 5>
As the inorganic particles, the same dry silica as in Example 4 was used, and the particles were placed in a reaction vessel, and while stirring under a nitrogen gas atmosphere, 100 g of the silica particles were shown in Table 3 as shown in Patent Document 1. 75 g of an aqueous dispersion of a mixed resin of No. 22 fluoroalkyl methacrylate resin and No. 26 fluoroalkyl methacrylate resin (No. 22: No. 26 mass ratio = 2: 1) (liquid component concentration: 20 mass). %) Was sprayed to prepare composite particles in the same manner as in Example 1 below.

<Comparative Example 6>
As the inorganic particles, the same dry silica as in Example 5 was used, and the particles were placed in a reaction vessel, and while stirring under a nitrogen gas atmosphere, 100 g of the silica particles were shown in Table 3 as shown in Patent Document 1. 100 g of an aqueous dispersion of a mixed resin of No. 23 polyfluoroalkyl methacrylate resin and No. 25 fluoroalkyl methacrylate resin (No. 23: No. 25 mass ratio = 2: 1) (liquid component concentration: 20). Mass%) was sprayed to prepare composite particles in the same manner as in Example 1.

<Comparative Example 7>
As the inorganic particles, the same dry silica as in Example 6 was used, and the particles were placed in a reaction vessel, and while stirring under a nitrogen gas atmosphere, 100 g of the silica particles were shown in Table 3 as shown in Patent Document 1. 125 g of an aqueous dispersion of a mixed resin of No. 24 polyfluoroalkyl methacrylate resin and No. 25 fluoroalkyl methacrylate resin (No. 24: No. 25 mass ratio = 2: 1) (liquid component concentration: 20). Mass%) was sprayed to prepare composite particles in the same manner as in Example 1.

<Comparative Example 8>
As the inorganic particles, the same dry silica as in Example 1 was used, and this was placed in a reaction vessel, and the fluoroacrylate resin of No. 9 shown in Table 2 was added to 100 g of the silica particles while stirring under a nitrogen gas atmosphere. 60 g (liquid component concentration: 20% by mass) of the aqueous dispersion was sprayed, heated and stirred at 300 ° C. for 30 minutes, and then cooled to room temperature to prepare composite particles in which resin-coated particles were aggregated.

<Comparative Example 9>
Using the same dry silica as in Example 1 as the inorganic particles, this was placed in a reaction vessel, and the fluoroalkyl acrylate of No. 13 shown in Table 2 was added to 100 g of the silica particles while stirring under a nitrogen gas atmosphere. 60 g (liquid component concentration: 20% by mass) of an aqueous dispersion of resin was sprayed, heated and stirred at 120 ° C. for 30 minutes, and then cooled to room temperature to prepare composite particles in which resin-coated particles were aggregated.

<Comparative Example 10>
Resin particles were prepared by using 100 g (liquid component concentration: 20% by mass) of an aqueous dispersion of No. 2 fluoroalkyl acrylate resin shown in Table 2 in the same manner as in Example 1 below, without using inorganic particles. did. FIG. 5 shows a photographic diagram of particles made of only fluoroalkyl acrylate resin at a magnification of 3,000 as observed by SEM.

<Comparative Example 11>
Using the same dry silica as in Example 1 as the inorganic particles, this was placed in a reaction vessel, and the fluoroalkyl acrylate of No. 11 shown in Table 2 was added to 100 g of the silica particles while stirring under a nitrogen gas atmosphere. 37.5 g (liquid component concentration: 20% by mass) of an aqueous dispersion of resin was sprayed, heated and stirred at 200 ° C. for 180 minutes, and then cooled to room temperature to prepare composite particles in which resin-coated particles were aggregated.

<Comparative Example 12>
As the inorganic particles, the same dry silica as in Example 4 was used, and this was placed in a reaction vessel, and the No. 3 polyfluoroalkyl shown in Table 2 was added to 100 g of the silica particles while stirring under a nitrogen gas atmosphere. 150 g (liquid component concentration: 20% by mass) of an aqueous dispersion of acrylate resin was sprayed, heated and stirred at 200 ° C. for 180 minutes, and then cooled to room temperature to prepare composite particles in which resin-coated particles were aggregated.

Table 4 below shows the types and average primary particle diameters of the inorganic particles, the type of resin in the coating layer, and the ratio of the amount of the resin liquid sprayed in Examples 1 to 15 and Comparative Examples 1 to 12.

Of the dry silica, dry alumina, dry titania, wet silica, aluminum hydroxide, calcium fluoride, magnesium fluoride, boron nitride, silica and titania obtained in Examples 1 to 15 and Comparative Examples 1 to 9, 11 and 12. _{The fluorine content, carbon content and volume-based average particle size (D 50} ) of 26 types of composite particles made from inorganic particles of composite oxide and the resin particles of Comparative Example 10 were measured by the above-exemplified method. .. Further, 27 kinds of composite particles and resin particles were added at a ratio of 7% by mass with respect to 100% by mass of ethanol, respectively, and uniformly dispersed to prepare a dispersion liquid, and this dispersion liquid was applied to the surface of a glass plate by a bar coater. It was applied and heated in an oven at 105 ° C. for 20 seconds to form 27 types of coatings having a thickness of 60 μm. Then, the contact angle of water, the contact angle of salad oil, and the contact angle of silicone oil with respect to 27 types of coating films were measured using a commercially available measuring device (contact angle meter manufactured by Kyowa Interface Science Co., Ltd., "Drop Master DM-301"). It was measured. Specifically, ion-exchanged water at 25 ° C., salad oil, and silicone oil having two different viscosities (300 cs, 100 cs) are prepared in a syringe, and water, salad oil, and silicone oil come into contact with the film surface in a stationary state. After that, the contact angle was measured.

The measurement results of the fluorine content, carbon content and volume-based average particle size (D ₅₀ ) are shown in Table 4 above, and the measurement results of water, salad oil and silicone oil are shown in Table 5 below. Further, FIGS. 2 and 3 show photographic drawings showing the oil repellency of the silicone oil on the coating film surfaces of Example 6 and Comparative Example 2, respectively. Further, FIG. 6 shows a photograph of the contact angles of water, salad oil, and 100 cs of silicone oil of Examples 1 to 8.

As is clear from FIGS. 4 and 5, since the composite particles of Example 3 are formed by aggregating several inorganic particles, they have a fractal surface due to fine irregularities on the surface of the composite particles. Since the resin particles of Comparative Example 10 were formed only of resin, the surface was smooth and did not have a fractal surface.

As is clear from Tables 4 and 5, in Comparative Example 1, since the spray amount of the resin component was 5.0 parts by mass, the fluorine content and the carbon content were reduced, and the contact angles of water and silicone oil were each reduced. Was low.

In Comparative Examples 2 to 7, since the coating layer is formed of the (poly) fluoro (alkyl) methacrylate resin shown in Patent Document 1, the silicone oil does not repel and the oil repellency is high regardless of the conditions under which the composite particles are formed. It was low. The oil repellency of the composite particles of Comparative Example 2 against silicone oil is shown in FIG.

In Comparative Example 8, since the liquid containing the resin was sprayed and then heat-treated at a high temperature of 300 ° C., the resin was thermally decomposed and water and oil repellency could not be obtained.

In Comparative Example 9, since the liquid containing the resin was sprayed and then heat-treated at a low temperature of 120 ° C., the resin component was not sufficiently dried and water remained in the composite particles, so that it was water- and oil-repellent. Was not obtained.

In Comparative Example 10, since the resin particles were formed only of resin and the surface was smooth and did not have a fractal surface, the contact angle with salad oil and silicone oil was about 75 to 77 degrees, but the contact angle with water was about 75 to 77 degrees. Was 0 degrees.

In Comparative Example 11, since the liquid containing the resin was sprayed and then heat-treated at 200 ° C. for a long time of 180 minutes, a part of the fluororesin (No. 11) component was poorly decomposed for a long time with poor thermal stability and was decomposed with water. The contact angles with the salad oil were 150 degrees and 143 degrees, respectively, but the contact angles with the silicone oil were as low as about 45 degrees, and oil repellency could not be obtained.

In Comparative Example 12, since a large amount of the liquid containing the resin was sprayed and then heat-treated, the fluororesin component covered on the surface of the composite particles became excessive, and the fractal structure formed by the fine particles was offset by the resin covered on the surface (surface). The contact angle with salad oil was 144 degrees, but the contact angles with water and silicone oil were low at 100 degrees and 40 degrees, respectively, and high water repellency. No oil repellency was obtained.

On the other hand, in Examples 1 to 15, the composite particles produced according to the requirements described in the fifth aspect of the present invention have a predetermined amount of resin liquid sprayed regardless of the type of inorganic particles. Since the surface of the inorganic particles is formed of a coating layer having a predetermined thickness containing a (poly) fluoro (alkyl) methacrylate resin, the contact angle with water and salad oil is large, and the contact with silicone oil is also large. It was found that the horns were large and the water and oil repellency was exhibited. In particular, as is clear from Example 6 of Tables 4, 5 and 2, the contact angle between the glass coating film and the silicone oil increases depending on the amount of the (poly) fluoro (alkyl) acrylate resin. It was found that the oil-repellent effect was enhanced.

The water- and oil-repellent coating film of the present invention is used in fields where water- and oil-repellent properties are required, such as electronic materials, construction, transportation equipment, office supplies, daily necessities, kitchen supplies, toiletry products, and medical supplies.

Claims (7)

A plurality of resin-coated particles in which a coating layer containing a fluoroalkyl acrylate resin or a fluoroacrylate resin is formed on the surface of inorganic particles having an average primary particle size of 5 to 100 nm are aggregated and have a fluorine content of 1.5 to 1. A composite particle for forming a water- and oil-repellent coating film, which is 7.5% by mass and has a volume-based average particle size (D _{50) of 1 to 100 μm.} The composite particle according to claim 1, wherein the composite particle has a carbon content of 2.0 to 10.0% by mass. The composite particle according to claim 1 or 2, wherein the inorganic particle is one or more particles selected from the group consisting of oxides, hydroxides, fluorides, nitrides and composite oxides. The composite particle according to claim 3, wherein the inorganic particle is a dry particle. Inorganic particles having an average primary particle size of 5 to 100 nm are placed in a reaction vessel, and a liquid containing a fluoroalkyl acrylate resin or a fluoroacrylate resin is sprayed in the reaction vessel while stirring the inorganic particles in an inert gas atmosphere. The inorganic particles are heat-treated at a temperature of 150 to 220 ° C. for 30 to 120 minutes while spraying so that the amount of the resin component is 7.5 to 25.0 parts by mass with respect to 100 parts by mass of the inorganic particles. The water and oil repellency according to any one of claims 1 to 4 is formed by coating the surface of the above with a fluoroalkyl acrylate resin layer or a fluoroacrylate resin layer to form resin-coated particles and agglomerate the resin-coated particles. A method for producing composite particles for forming a coating film. Solvent 100 using the water-repellent oil-repellent coating film-forming composite particles according to any one of claims 1 to 4 or the water-repellent oil-repellent coating film-forming composite particles produced by the method according to claim 5 as a solvent. A method of preparing a dispersion liquid by dispersing the composite particles at a ratio of 10 to 20% by mass with respect to mass%, and applying the dispersion liquid to the surface of a substrate to form a water-repellent oil-repellent coating film. The contact angle of water with respect to the formed water- and oil-repellent coating film is 110 degrees or more at 25 ° C., the contact angle of salad oil is 120 degrees or more at 25 ° C., and the contact angle of silicone oil is 60 degrees or more at 25 ° C. The method for forming a water- and oil-repellent coating film according to claim 6.