Dispersants, dispersion compositions, and coating materials for inorganic fine particles

Abstract

The present invention provides a dispersant capable of uniformly dispersing inorganic fine particles in a hydrophobic medium, and a dispersion composition in which inorganic fine particles are uniformly dispersed in a hydrophobic medium. [Solution] The present invention provides a dispersant for dispersing inorganic fine particles in a hydrophobic medium, wherein the dispersant comprises a fluoroalkyl group-containing phosphinic acid and / or its metal salt represented by the following general formula (1). JPEG2026064387000013.jpg35170 (In the formula, n represents an integer between 0 and 16. X represents a hydrogen atom or an alkali metal.)

Description

[Technical Field]

[0001] This invention relates to a dispersant for dispersing inorganic fine particles in a hydrophobic medium and a dispersion composition using the same. [Background technology]

[0002] Inorganic microparticles are used in rubber, resins, inks, paints, adhesives, paper, abrasives, coatings, pharmaceuticals, cosmetics, and other products. For inorganic microparticles to function effectively in these products, they must be uniformly dispersed within the product.

[0003] One method for uniformly dispersing inorganic fine particles in these products is to uniformly disperse the inorganic fine particles in a hydrophobic solvent and then uniformly incorporate them into the desired material. In many cases, a dispersant is used in this process.

[0004] Various dispersants have been proposed, including carboxylic acid-based, sulfonic acid-based, phosphate ester-based, and alkylamine salt-based agents.

[0005] While fluoroalkyl group-containing phosphinic acid is disclosed, for example, in Patent Documents 1 to 3 below as a surface treatment agent for imparting water-repellent and oil-repellent properties to cosmetic powders, it does not disclose anything about uniformly dispersing inorganic fine particles in a hydrophobic solvent. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 05-339126 [Patent Document 2] Japanese Patent Application Publication No. 05-339127 [Patent Document 3] Japanese Patent Application Publication No. 05-339128 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] In the process of developing materials for imparting functions to phosphinic acid derivatives, the inventors of the present invention have found that those composed of specific fluoroalkyl group-containing phosphinic acids and / or metal salts thereof can be suitably used as dispersants for dispersing inorganic fine particles in a hydrophobic medium, and have thus completed the present invention.

[0008] That is, an object of the present invention is to provide a dispersant capable of uniformly dispersing inorganic fine particles in a hydrophobic medium and a dispersion composition in which the inorganic fine particles are uniformly dispersed in the hydrophobic medium.

Means for Solving the Problems

[0009] The above problems are solved by the following present invention. The first invention provided by the present invention is a dispersant for dispersing inorganic fine particles in a hydrophobic medium, wherein the dispersant is a dispersant for inorganic fine particles composed of a fluoroalkyl group-containing phosphinic acid represented by the following general formula (1) and / or a metal salt thereof.

[0010]

Chemical formula

[0011] Further, the second invention that the present invention intends to provide is a dispersion composition containing inorganic fine particles, a hydrophobic medium, and the dispersant of the first invention.

Effects of the Invention

[0012] According to the present invention, it is possible to provide a dispersant capable of uniformly dispersing inorganic fine particles in a hydrophobic medium and a dispersion composition in which the inorganic fine particles are uniformly dispersed in the hydrophobic medium.

Brief Description of the Drawings

[0013] [Figure 1]Particle size distribution diagrams (Measurement 1) measured using the dispersions of Examples 1-2 and Comparative Examples 1-3. [Figure 2] Particle size distribution diagrams (Measurement 2) measured using the dispersions of Examples 1-2 and Comparative Examples 1-3. [Figure 3] Particle size distribution diagrams (Measurement 1) measured using the dispersions of Examples 3-4 and Comparative Examples 4-6. [Figure 4] Particle size distribution diagrams (Measurement 2) measured using the dispersions of Examples 3-4 and Comparative Examples 4-6. [Modes for carrying out the invention]

[0014] The present invention will be described below based on preferred embodiments. The present invention provides a dispersant for inorganic fine particles, which is a dispersant for dispersing inorganic fine particles in a hydrophobic medium, characterized in that the dispersant comprises a fluoroalkyl group-containing phosphinic acid and / or its metal salt, represented by the following general formula (1).

[0015] [ka] (In the formula, n represents an integer between 0 and 16. X represents a hydrogen atom or an alkali metal.)

[0016] In general formula (1), X represents a hydrogen atom or an alkali metal such as sodium or potassium. In general formula (1), n ​​represents an integer from 0 to 16, preferably from 1 to 9, and particularly preferably from 1 to 4, from the viewpoint of improving wettability and affecting living organisms.

[0017] Fluoroalkyl group-containing phosphinic acid and / or its metal salts represented by general formula (1) can be produced, for example, by reacting hypophosphorous acid (2a) and / or hypophosphate salt (2b) with an olefin (3) in the presence of a radical initiator and using a carboxylic acid selected from acetic acid, propionic acid, butyric acid, and 2-ethylhexanoic acid as the reaction solvent, according to reaction scheme (1) or reaction scheme (2) below (see, for example, JP 2008-517947, JP 2001-525328, JP 2017-513817, etc.).

[0018] [ka] (In the formula, n is equivalent to that in formula (1) above.)

[0019] [ka] (In the formula, n is equivalent to formula (1) above. X 1 (This indicates alkali metals.)

[0020] In the present invention, the fluoroalkyl group-containing phosphinic acid and / or its metal salt represented by general formula (1) is preferably produced by a method comprising the following first and second steps, from the viewpoint of being able to produce the target fluoroalkyl group-containing phosphinic acid and / or its metal salt in an industrially advantageous manner.

[0021] Step 1: A step of preparing a carboxylic acid solution containing a raw material phosphorus compound by dissolving or suspending hypophosphorous acid (2a) and / or hypophosphate salt (2b) in a carboxylic acid. Step 2: A step in which a reaction is carried out by adding olefin (3) and a radical initiator to the raw material phosphorus compound-containing carboxylic acid solution at a reaction temperature of over 100°C and 200°C or less and a reaction pressure of 0.20 MPa or less to obtain fluoroalkyl group-containing phosphinic acid (1a) and / or its metal salt (1b).

[0022] Furthermore, when using a hydrated sodium hypophosphate salt (2b) as the reaction raw material in the first step, it is preferable to use a dehydrated salt with a water content of 10% by mass or less, preferably 8% by mass, and particularly preferably 4% by mass or less, because this prevents reflux of water and makes it easier to raise the temperature in the reaction system to over 100°C. For example, compared to the case where the same carboxylic acid is used as the reaction solvent, this is preferable from the viewpoint of further improving the yield of the target fluoroalkyl group-containing phosphinic acid (1a) and / or its metal salt (1b).

[0023] Furthermore, if a hypophosphate (2b) such as an alkali metal hypophosphate salt is used as a reaction raw material in the first step, a reaction solution containing a fluoroalkyl group-containing phosphinate (1b) can be obtained by performing the second step. In order to obtain fluoroalkyl group-containing phosphinic acid (1a) from the fluoroalkyl group-containing phosphinate (1b), water is added to the reaction solution containing the fluoroalkyl group-containing phosphinate (1b) obtained in the second step to establish an aqueous phase and an organic phase, the resulting organic phase is repeatedly extracted and washed with neutral or alkaline water, and then the organic phase is made acidic to recover the fluoroalkyl group-containing phosphinic acid (1a).

[0024] In the present invention, examples of inorganic fine particles dispersed in a hydrophobic medium include oxides, nitrides, hydroxides, carbonates, silicides, and so on. Metal oxides and metal nitrides are particularly preferred from the viewpoint of improving the functionality of resins containing them as fillers. Furthermore, the inorganic fine particles may contain one or more metal elements.

[0025] Specific examples of the inorganic fine particles include, for example, silica, aluminum oxide, zirconium oxide, tin oxide, yttrium oxide, bismuth oxide, cerium oxide, indium oxide, titanium oxide, zinc oxide, magnesium oxide, vanadium oxide, tungsten oxide, copper oxide, silver oxide, hafnium oxide, magnetite, calcium carbonate, magnesium carbonate, zinc carbonate, barium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, iron hydroxide, zirconia, aluminum nitride, silicon nitride, silicon carbide, barium titanate, strontium titanate, zirconium tungsten phosphate, hydrotalcite, zeolite, indium tin oxide, etc.

[0026] In addition, the metal oxides and metal nitrides may be doped with different metal elements such as, for example, gallium, tin, antimony, europium, manganese, cesium, etc. Specific examples include inorganic phosphors, such as Y3Al5O 12 :Ce 3+ 、La3Si6N 11 :Ce 3+ 、(La,Y)3Si6N 11 :Ce 3+ 、CaAlSiN3:Eu 2+ 、(Sr,Ca)AlSiN3:Eu 2+ 、(Si,Al)3(O,N)4:Eu 2+ 、Y3(Al,Ga)5O 12 :Ce 3+ 、Lu3Al5O 12 :Ce 3+ 、(Sr,Ba) 10 (PO4)6Cl2:Eu 2+ etc.

[0027] The particle diameter of the inorganic fine particles is the average particle diameter (D 50 ) obtained by the dynamic light scattering method, and it is preferably 10 to 2000 nm, more preferably 10 to 500 nm from the viewpoint of the stability of the dispersion liquid after dispersion.

[0028] In the present invention, the hydrophobic medium for dispersing inorganic fine particles is not particularly limited, but examples of hydrophobic solvents include: aliphatic hydrocarbon solvents such as heptane and octane; aromatic hydrocarbon solvents such as toluene, xylene, ethylbenzene, and tetralin; aliphatic or alicyclic hydrocarbon solvents such as n-hexane, n-heptane, mineral spirits, and cyclohexane; halogenated solvents such as methyl chloride, methyl bromide, methyl iodide, methylenedichloride, carbon tetrachloride, trichloroethylene, and perchloroethylene; ester or ester ether solvents such as ethyl acetate, butyl acetate, methoxybutyl acetate, methyl cellosolve acetate, and ethyl cellosolve acetate; ether solvents such as diethyl ether and propylene glycol monomethyl ether; ketone solvents such as methyl isobutyl ketone, di-n-butyl ketone, and cyclohexanone; isoparaffinic hydrocarbon solvents and fluorine-containing solvents. These hydrophobic solvents can be used one or more of them. In the present invention, among these, fluorine-containing solvents are particularly preferred from the viewpoint of wettability with alkyl fluoride in the structure of the dispersant and compatibility when mixed with fluororesins.

[0029] The fluorine-containing solvent is not particularly limited, but examples include perfluorocarbons, hydrochlorofluorocarbons, hydrofluoroethers, hydrofluoroolefins, perfluoroolefins, chlorofluoroolefins, hydrochlorofluoroolefins, fluorine-containing alcohols, aromatic fluorine compounds, and the like.

[0030] Specific examples of fluorine-containing solvents include, for example, perfluorohexane, perfluoro-N-methylmorpholine, perfluoro-N-propylmorpholine, perfluorotriethylamine, perfluoromethyldibutylamine, perfluorotributylamine, CF3CF2CHCl2, CF3CHFCHFCF2CF3, CF3CF2CF2CF2CF2CF2H, CF3(CF2)5CH2CH3, C4F9OCH3, C4F9OC2H5, C2F5CF(OCH3)C3F7, and 1,1,2,2-Tetrone. Lafluoroethyl-2,2,2-trifluoroethyl ether, 2,2,2-trifluoroethanol, 1,1,1,3,3,3-hexafluoroisopropanol, 1,2,2,3,3,4,4-heptafluorocyclopentane, hexafluorobenzene, 1,1,3-trichloro-2,3,3-trifluoropropene, 1,1,2-trichloro-3,3,3-trifluoropropene, 1,1,1,4,4,4-hexafluoro-2-butene, 1-chloro-2,3,3,3-tetrafluoropropene 2-chloro-1,3,3,3-tetrafluoropropene, 1-chloro-1,3,3,3-tetrafluoropropene, 2-chloro-3,3,3-trifluoropropene, 1-chloro-2,3,3-trifluoropropene, 1-chloro-3,3,3-trifluoropropene, 1-chloro-1,3,3-trifluoropropene, 2-chloro-1,3,3-trifluoropropene, 2-chloro-1,1,3-trifluoropropene, 3-chloro-1,2,3-trifluoropropene, 3-chloro-1,1 Examples include 2-trifluoropropene, 1,2-dichloro-3,3,3-trifluoropropene, 2,3-dichloro-3,3-difluoropropene, 1,2,3-trichloro-3,3-difluoropropene, 2,3-dichloro-1,1-difluoropropene, 2,3,3-trichloro-3-fluoropropene, 1,3-dichloro-2,3,3-trifluoropropene, 1-chloro-2,3,3,4,4,5,5-heptafluoro-1-pentene, etc., which can be used individually or in combination of two or more.

[0031] Furthermore, the hydrophobic solvent may be a mixed solvent of a hydrophobic solvent and a hydrophilic solvent, as long as it is not freely miscible with water.

[0032] Furthermore, the hydrophobic medium may be, for example, a polymer solution obtained by dissolving a thermoplastic resin or a thermosetting resin in a solvent.

[0033] In the present invention, a polymer solution obtained by dissolving a fluorine-containing polymer in an organic solvent is preferred from the viewpoint of compatibility with the dispersant.

[0034] There are no particular restrictions on the fluorine-containing polymer, but examples include polytetrafluoroethylene (PTFE), polyvinyl difluoride (PVdF), vinyl difluoride / hexafluoropropylene copolymer (PVdF-HFP), vinyl difluoride / hexafluoropropylene / tetrafluoroethylene copolymer (PVdF-HFP-TFE), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), tetrafluoroethylene / hexafluoropropylene / perfluoroalkyl vinyl ether copolymer (FEP), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), poly(chlorotrifluoroethylene) (PCTFE), and tetrafluoroethylene / chlorotrifluoroethylene / perfluoroalkyl vinyl ether copolymer (CP Examples of T) include tetrafluoroethylene / ethylene / perfluoro(1,1,5-trihydro-1-pentene) copolymer (ETFE), tetrafluoroethylene / ethylene / perfluorobutylethylene copolymer (ETFE), tetrafluoroethylene / ethylene / hexafluoropropylene / perfluoro(1,1,5-trihydro-1-pentene) copolymer (EFEP), tetrafluoroethylene / ethylene / hexafluoropropylene / perfluorobutylethylene copolymer (EFEP), ethylene / chlorotrifluoroethylene copolymer (ECTFE), poly(vinylidene fluoride) (PVdF), tetrafluoroethylene / vinylidene fluoride copolymer (VT), and tetrafluoroethylene / hexafluoropropylene / vinylidene fluoride copolymer (THV).

[0035] As the organic solvent for dissolving fluorine-containing polymers, generally, a highly polar organic solvent or a fluorine-containing solvent can be used alone, or a mixed solvent of a highly polar organic solvent and a fluorine-containing solvent can be used. Furthermore, the highly polar solvent used may be a hydrophilic organic solvent, as long as it is in a state where it does not freely mix with water while containing the fluorine-containing polymer and the solvent that dissolves the fluorine-containing polymer.

[0036] Examples of highly polar organic solvents include alcohols, amides, ketones, ethers, nitrile compounds, and sulfur-containing compounds. Specifically, alcohols include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, t-butyl alcohol, various isomers of pentanol, methyl cellosolve, ethyl cellosolve, and propyl cellosolve. Amides include dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. Ketones include acetone and 2-butanone. Ethers include ethyl ether, propyl ether, isopropyl ether, butyl ether, dimethoxyethane, diethylene glycol dimethyl ether, tetrahydrofuran, and dioxane. Nitrile compounds include acetonitrile, propionitrile, valeronitrile, malononitrile, and adiponitrile. Sulfur-containing compounds include dimethyl sulfoxide and sulfolane. Examples of fluorine-containing solvents include the aforementioned perfluorocarbons, hydrochlorofluorocarbons, hydrofluoroethers, hydrofluoroolefins, perfluoroolefins, chlorofluoroolefins, hydrochlorofluoroolefins, fluorine-containing alcohols, aromatic fluorine compounds, and the like. The organic solvent used to dissolve the fluorine-containing polymer can be one or more types.

[0037] The dispersion composition according to the present invention is characterized by comprising the aforementioned inorganic fine particles, hydrophobic medium, and dispersant.

[0038] From the viewpoint of the stability of the dispersion after dispersion, it is preferable that the content of inorganic fine particles in the dispersion composition be 1 to 30% by mass, preferably 1 to 10% by mass.

[0039] The amount of dispersant in the dispersion composition is preferably 1 to 200 parts by mass, more preferably 1 to 100 parts by mass, per 100 parts by mass of inorganic fine particles, as this allows for successful dispersion of the inorganic fine particles and also allows the composite of the dispersant and inorganic fine particles to be used directly as a filler for resin addition.

[0040] In the dispersion composition of the present invention, if the hydrophobic medium is a polymer solution containing a resin component such as a thermoplastic resin or a thermosetting resin, it is preferable that the resin component be present in an amount of 10 to 80% by mass, preferably 20 to 60% by mass.

[0041] Furthermore, the dispersion composition of the present invention may contain known additives added to inorganic fine particles or fluorine-containing polymers in amounts that do not impair the effects of the present invention. Examples of known additives include leveling agents, ultraviolet absorbers, antioxidants, viscosity modifiers, antistatic agents, flame retardants, and colorants.

[0042] The dispersion composition according to the present invention can be prepared by mixing inorganic fine particles, a hydrophobic medium, a dispersant, and additives or components added as needed using known mechanical means. Examples of mixing devices include automatic orbital mixers, homogenizers, ultrasonic stirrers, rocking mills, ball mills, jet mills, spike mills, bead mills, roll mills, sand mills, paint shakers, and the like.

[0043] The dispersion composition according to the present invention, for example, inorganic fine particles obtained by removing the solvent from the dispersion, can be suitably used as a resin additive filler, a light-emitting diode, and the like. Furthermore, a dispersion composition according to the present invention that contains a fluorine-containing polymer can be suitably used as a coating material.

[0044] The coating material of the present invention is first applied to the surface of a substrate by impregnation, curtain coating, gravure coating, wire bar coating, spray coating, reverse coating, die coating, or the like, and then dried to remove the solvent, thereby forming a film of non-volatile components on the surface of the substrate.

[0045] Because the coating material according to the present invention has excellent chemical resistance, it can be used as a coating material for electronic components, containers, piping, etc. [Examples]

[0046] The present invention will be described below with reference to examples, but the present invention is not limited to these examples. <Fluoroalkyl group-containing phosphinic acid sample>

[0047] [ka]

[0048] <Preparation of anhydrous sodium hypophosphate> 4.24 g (0.0400 mol) of sodium hypophosphite monohydrate was weighed into a 100 mL round-bottom flask, and the sodium hypophosphite monohydrate was dehydrated using a rotary evaporator under conditions of 0.003 MPa and 90°C for 1 hour. After dehydration, it was estimated that 3.0 mass% of water remained in the anhydrous sodium hypophosphite, according to the following calculation formula (1). Water content (mass%)=(A / B)×100 (1) (In the formula, A is the mass (g) lost when sodium hypophosphite monohydrate is dehydrated using a rotary evaporator under conditions of 0.02 MPa and 80°C for 1 hour, and B is the mass (g) of sodium hypophosphite monohydrate before dehydration treatment.)

[0049] <Fluoroalkyl group-containing phosphinic acid (Sample C6F 13 Preparation of ) In a 100 ml four-necked flask equipped with a nitrogen-purged stirrer, thermometer, and dropping funnel, 0.88 g (0.01 mol) of anhydrous sodium hypophosphite prepared above, 20 ml (19.8 g) of propionic acid, and 13.8 g (0.04 mol) of 1H,1H,2H-tridecafluoro-1-octene were added. The mixture was refluxed at an internal temperature of 130-133°C, and 0.4 g (0.0016 mol) of 2,2'-azobis(2,4-dimethylvaleronitrile) dissolved in 10 ml of propionic acid was added dropwise over 2 hours. The mixture was then heated at reflux temperature for 3 hours. Furthermore, 0.2 g (0.0008 mol) of 2,2'-azobis(2,4-dimethylvaleronitrile) dissolved in 10 ml of propionic acid was added dropwise over 1 hour, and the mixture was aged for 3 hours. 31 The reaction was terminated after confirming that the remaining amount of sodium hypophosphite was less than 1% using P-NMR. Propionic acid and unreacted olefins were removed from the reaction solution using an evaporator. Hydrochloric acid (an aqueous hydrochloric acid solution prepared by diluting 1 volume of concentrated hydrochloric acid with 1 volume of pure water) was added to the resulting slurry to acidify it to pH 1. 100 ml of chloroform and 50 ml of pure water were added, the precipitate was filtered off, and the mixture was washed with pure water. By vacuum drying, 5.6 g of a white powder solid with a melting point of 160.2-163.0°C was obtained (crude yield 58%). 31 P-NMR analysis revealed a purity of 95.2% (impurities: monophosphinic acid 4.5%). This was used as a dispersant. (Fluoroalkyl group-containing phosphinic acid (Sample C6F 13 (Identification data) 31 P-NMR (CD3COOD); 28.69 ppm 1 H-NMR(CD3COOD);2.02ppm(m,8H,-CH2-CH2-),11.0ppm(s,1H,POOH) NMR analysis confirmed that it is bis(1H,1H,2H,2H-tridecafluorooctyl)phosphinic acid.

[0050] <Preparation of fluoroalkyl group-containing phosphinic acid (sample C4F9)> Except for using 0.04 moles of 1H,1H,2H-nonafluoro-1-hexene instead of 1H,1H,2H-heptadecafluoro-1-decene, the fluoroalkyl group-containing phosphinic acid (Sample C6F) was used. 13 A white powder solid was obtained in the same manner as described above. This was used as a dispersant. (Identification data for fluoroalkyl group-containing phosphinic acid (sample C4F9)) 31 P-NMR (CD3COOD); 44.34 ppm 1 H-NMR(CD3COOD);2.02ppm(m,8H,-CH2-CH2-),11.0ppm(s,1H,POOH) NMR analysis confirmed that it is bis(1H,1H,2H,2H-nonafluorohexyl)phosphinic acid.

[0051] <Inorganic fine particles> The inorganic microparticles used were commercially available ones as shown in Table 1.

[0052] [Table 1]

[0053] {Example 1} 1-chloro-2,3,3-trifluoropropene (Amorea® AS-300; manufactured by AGC Inc.) (hereinafter referred to as AS-300) was used as the hydrophobic medium, and inorganic fine particles 1 were used as the inorganic fine particles. A 15 ml glass container was prepared, and AS-300 (4.75 g) and inorganic fine particles 1 (0.048 g) were placed in this container to prepare a slurry. Next, the fluoroalkyl group-containing phosphinic acid (sample C4F9) (0.048 g) prepared above was added to this slurry, and ultrasonic irradiation was performed at 15 W for 30 seconds to prepare a 1 wt% dispersion of inorganic fine particles 1.

[0054] {Example 2} Replace fluoroalkyl group-containing phosphinic acid (sample C6F9) with fluoroalkyl group-containing phosphinic acid (sample C6F9)13 A 1 wt% dispersion of inorganic fine particles 1 was prepared in the same manner as in Example 1, except that (0.048 g) of ) was added.

[0055] {Comparative Example 1} A 1 wt% dispersion of inorganic fine particles 1 was prepared in the same manner as in Example 1, except that fluoroalkyl group-containing phosphinic acid (sample C4F9) was not added. A dispersion sample was prepared.

[0056] {Comparative Example 2} A 1 wt% dispersion of inorganic fine particles 1 was prepared in the same manner as in Example 1, except that oleic acid (0.048 g) was added as a dispersant instead of fluoroalkyl group-containing phosphinic acid (sample C4F9).

[0057] {Comparative Example 3} A 1 wt% dispersion of inorganic fine particles 1 was prepared in the same manner as in Example 1, except that hexadecafluorononanoic acid (0.048 g) was added as a dispersant instead of fluoroalkyl group-containing phosphinic acid (sample C4F9).

[0058] <Evaluation of dispersant performance> (Particle size distribution: measurement 1) The dispersions prepared in the examples and comparative examples were stirred within one hour of preparation by inverting the glass container containing the dispersion five times, and then, at room temperature (25°C), the particle size distribution was measured using a dynamic light scattering method with a particle size distribution device (Nanotrac, Microtrac Bell). 50 and D 90 The following measurements were taken. The results are shown in Table 2. The particle size distribution is shown in Figure 1. Note that the dispersion sample is D 50 and D 90 A smaller value indicates less aggregation of inorganic fine particles in the dispersion. (Particle size distribution: Measurement 2) The dispersions prepared in the examples and comparative examples were left at 25°C for 14 days, stirred by inverting the glass containers containing the dispersions five times, and then, at room temperature (25°C), the particle size distribution was measured using a dynamic light scattering method with a particle size distribution device (Nanotrac, Microtrac-Bel). 50 and D 90 The following measurements were taken. The results are shown in Table 2. The particle size distribution diagram is also shown in Figure 2. Note that the dispersion sample is D 50 and D 90 A smaller value indicates less aggregation of inorganic particles in the dispersion. Also, D of particle size distribution measurement 1 50 and D 90 The value and the D of particle size distribution measurement 2 50 and D 90 A smaller difference from the value indicates less aggregation of inorganic fine particles in the dispersion sample even after standing, suggesting superior dispersion stability.

[0059] [Table 2]

[0060] {Example 3} Methyl ethyl ketone (MEK) was used as the hydrophobic medium, and inorganic fine particles 1 were used as the inorganic fine particles. A 15 ml glass container was prepared, and a slurry was prepared by adding methyl ethyl ketone (9.5 g) and inorganic fine particles 1 (0.5 g) to this glass container. Next, the fluoroalkyl group-containing phosphinic acid (sample C4F9) (0.025 g) prepared above was added to this slurry, and the mixture was ultrasonically irradiated at 15 W for 30 minutes to prepare a 5 wt% dispersion of inorganic fine particles 1. The particle size distribution of the prepared dispersion was measured in the same manner as in Example 1. The results are shown in Table 3. The particle size distribution diagram for Measurement 1 is shown in Figure 3, and the particle size distribution diagram for Measurement 2 is shown in Figure 4.

[0061] {Example 4} Fluoroalkyl group-containing phosphinic acid (Sample C6F) can be replaced with fluoroalkyl group-containing phosphinic acid (Sample C6F)13 A 5 wt% dispersion of inorganic fine particles 1 was prepared in the same manner as in Example 3, except that (0.025 g) of ) was added. The particle size distribution of the prepared dispersion was measured in the same manner as in Example 1. The results are shown in Table 3. The particle size distribution diagram for Measurement 1 is shown in Figure 3, and the particle size distribution diagram for Measurement 2 is shown in Figure 4.

[0062] {Comparative Example 4} A 5 wt% dispersion of inorganic fine particles 1 was prepared in the same manner as in Example 3, except that fluoroalkyl group-containing phosphinic acid (sample C4F9) was not added. Furthermore, the particle size distribution was measured in the same manner as in Example 1. The results are shown in Table 3. The particle size distribution diagram for Measurement 1 is shown in Figure 3, and the particle size distribution diagram for Measurement 2 is shown in Figure 4.

[0063] {Comparative Example 5} A 5 wt% dispersion of inorganic fine particles 1 was prepared in the same manner as in Example 3, except that oleic acid (0.025 g) was added as a dispersant instead of fluoroalkyl group-containing phosphinic acid (sample C4F9). The particle size distribution of the prepared dispersion was measured in the same manner as in Example 1. The results are shown in Table 3. The particle size distribution diagram for Measurement 1 is shown in Figure 3, and the particle size distribution diagram for Measurement 2 is shown in Figure 4.

[0064] {Comparative Example 6} A 5 wt% dispersion of inorganic fine particles 1 was prepared in the same manner as in Example 3, except that hexadecafluorononanoic acid (0.025 g) was added as a dispersant instead of fluoroalkyl group-containing phosphinic acid (sample C4F9). The particle size distribution of the prepared dispersion was measured in the same manner as in Example 1. The results are shown in Table 3. The particle size distribution diagram for Measurement 1 is shown in Figure 3, and the particle size distribution diagram for Measurement 2 is shown in Figure 4.

[0065] [Table 3]

[0066] {Example 5} Toluene was used as the hydrophobic medium, and inorganic fine particles 1 were used as the inorganic fine particles. A 15 ml glass container was prepared, and toluene (4.75 g) and inorganic fine particles 1 (0.048 g) were placed in this container to prepare a suspension. Next, the fluoroalkyl group-containing phosphinic acid (sample C4F9) (0.048 g) prepared above was added to this suspension, and ultrasonic irradiation was performed at 15 W for 30 seconds to prepare a 1 wt% dispersion of inorganic fine particles 1. The particle size distribution of the prepared dispersion was measured in the same manner as in Example 1. The results are shown in Table 4.

[0067] {Example 6} Replace fluoroalkyl group-containing phosphinic acid (sample C6F9) with fluoroalkyl group-containing phosphinic acid (sample C6F9) 13 A 1 wt% dispersion of inorganic fine particles 1 was prepared in the same manner as in Example 5, except that (0.048 g) of ) was added. The particle size distribution of the prepared dispersion was measured in the same manner as in Example 1. The results are shown in Table 4.

[0068] {Comparative Example 7} A 1 wt% dispersion of inorganic fine particles 1 was prepared in the same manner as in Example 5, except that fluoroalkyl group-containing phosphinic acid (sample C4F9) was not added. The particle size distribution of the prepared dispersion was measured in the same manner as in Example 1. The results are shown in Table 4.

[0069] {Comparative Example 8} A 1 wt% dispersion of inorganic fine particles 1 was prepared in the same manner as in Example 5, except that 1H,1H,2H,2H-perfluorooctanephosphonic acid (0.048 g) was added as a dispersant instead of fluoroalkyl group-containing phosphinic acid (sample C4F9). The particle size distribution of the prepared dispersion was measured in the same manner as in Example 1. The results are shown in Table 4.

[0070] [Table 4]

[0071] {Examples 7-10 and Comparative Examples 9-16} A 30 ml glass container was prepared, and AS-300 (20.0 g) and the inorganic fine particles (0.05 g) shown in Table 5 were placed in this container to prepare a slurry. Next, the dispersant (0.05 g) shown in Table 5 was added to this slurry, and ultrasonic irradiation was performed at 15 W for 30 seconds to prepare a 0.25 wt% dispersion of inorganic fine particles. The dispersions obtained in the examples and comparative examples were stirred within one hour of preparation by inverting the glass container containing the dispersion five times, and then, at room temperature (25°C), the particle size distribution was measured using a dynamic light scattering method with a particle size distribution device (Nanotrac, Microtrac Bell). 50 and D 90 The following measurements were taken. The results are shown in Table 5.

[0072] [Table 5]

[0073] {Example 11} A 30 ml glass container was prepared, and a slurry was prepared by charging it with a 15.4% solution (10.3 g) of methyl ethyl ketone (MEK) of vinylidene fluoride / tetrafluoroethylene / hexafluoropropylene copolymer (Daiel G902: manufactured by Daikin Industries, Ltd.) and inorganic fine particles 4 (0.1 g) as a hydrophobic medium. Next, the fluoroalkyl group-containing phosphinic acid (sample C4F9) (0.1 g) prepared above was added to this slurry, and the mixture was ultrasonically irradiated at 15 W for 30 minutes to prepare a 0.95 wt% dispersion of inorganic fine particles 4. Within one hour of preparing the dispersion, the glass container containing the dispersion was stirred by inverting it five times, and then the particle size distribution was measured at room temperature (25°C) using a dynamic light scattering particle size distribution device (Nanotrac, Microtrac-Bel). 50 and D 90 The following measurements were taken. The results are shown in Table 6.

[0074] {Comparative Example 14} A 0.95 wt% dispersion of inorganic fine particles 4 was prepared in the same manner as in Example 11, except that a fluoroalkyl group-containing phosphinic acid (sample C4F9) was not added. Within one hour of preparing the dispersion, the glass container containing the dispersion was stirred by inverting it five times, and then the particle size distribution was measured at room temperature (25°C) using a dynamic light scattering method with a particle size distribution device (Nanotrac, Microtrac-Bel). 50 and D 90 The following measurements were taken. The results are shown in Table 6.

[0075] [Table 6]

[0076] {Example 12} A 30 ml glass container was prepared, and a slurry was prepared by charging it with a 15.4% solution (10.3 g) of methyl ethyl ketone (MEK) of vinylidene fluoride / tetrafluoroethylene / hexafluoropropylene copolymer (Daiel G902: manufactured by Daikin Industries, Ltd.) and inorganic fine particles 4 (1.0 g) as a hydrophobic medium. Next, 0.1 g of the fluoroalkyl group-containing phosphinic acid (sample C4F9) prepared above was added to this slurry, and the mixture was ultrasonically irradiated at 15 W for 30 minutes to prepare an 8.8 wt% dispersion of inorganic fine particles 4. Two ml of the obtained dispersion was dropped into a 40 mm diameter PTFE Petri dish and left to stand. After the solvent had completely evaporated, the dispersion was carefully peeled off to create a fluororesin film in which inorganic fine particles 4 were dispersed (film thickness: 0.089 mm). Elemental mapping of the Al element caused by the inorganic fine particles 4 was performed on the front and back surfaces of the obtained fluororesin film using SEM-EDX (HITACHI SU8220) to confirm the distribution of inorganic fine particles 4. It was confirmed that the inorganic fine particles 4 were uniformly distributed on both the front and back surfaces of the fluororesin film.

[0077] {Comparative Example 15} A fluororesin film containing dispersed inorganic fine particles 4 was prepared in the same manner as in Example 12, except that fluoroalkyl group-containing phosphinic acid (sample C4F9) was not added (film thickness: 0.116 mm). Elemental mapping of the Al element caused by inorganic fine particles 4 was performed on the front and back surfaces of the obtained fluororesin film using SEM-EDX (HITACHI SU8220) to confirm the distribution of inorganic fine particles 4. It was confirmed that inorganic fine particles 4 were uniformly distributed on the back surface of the fluororesin film, but that they were non-uniformly distributed on the front surface of the fluororesin film.

Claims

1. A dispersant for dispersing inorganic fine particles in a hydrophobic medium, wherein the dispersant comprises a fluoroalkyl group-containing phosphinic acid and / or its metal salt represented by the following general formula (1). 【Chemistry 1】 (In the formula, n represents an integer between 0 and 16. X represents a hydrogen atom or an alkali metal.)

2. The dispersant for inorganic fine particles according to claim 1, wherein the hydrophobic medium is a solution obtained by dissolving a fluorine-containing solvent and / or a fluorine-containing polymer in a solvent.

3. The dispersant for inorganic fine particles according to claim 1 or 2, wherein the inorganic fine particles are selected from metal oxides and metal nitrides.

4. The dispersant for inorganic fine particles according to claim 1 or 2, wherein the average particle size of the inorganic fine particles is 10 to 2000 nm.

5. A dispersion composition comprising inorganic fine particles, a hydrophobic medium, and the dispersant for inorganic fine particles described in claim 1.

6. A coating material comprising the dispersion composition according to claim 5.

Images