JP6498460B2 - Inorganic fiber sheet - Google Patents

Description

  The present invention relates to an inorganic fiber sheet.

  Since inorganic particles have various functions, they are applied to various uses. For example, by including inorganic particles in the fiber, functions such as heat resistance, strength, and conductivity can be imparted to the fiber.

  For example, International Publication WO 2009/096365 pamphlet (Patent Document 1) states that “a composite of inorganic nanoparticles and a polymer, and the average dispersed particle size of the inorganic nanoparticles in the composite is 0.5 nm or more. A fiber-shaped inorganic nanoparticle-polymer composite in which 70% or more of the inorganic nanoparticles in the composite are dispersed in a form having a dispersed particle size of 30 nm or less "is proposed. In addition, the inorganic nanoparticle-polymer composite in such a fiber form is a fiber modified with inorganic nanoparticles. However, since inorganic nanoparticles are highly dispersed in a polymer, it has been difficult to fully exhibit the functions of the inorganic nanoparticles. For example, even if trying to exert the photocatalytic function of the titanium oxide particles, such a function can be exerted only on a part of the titanium oxide particles exposed on the fiber surface, so that a sufficient photocatalytic function cannot be exhibited. It has been difficult to fully exhibit the function of the inorganic particles.

International Publication WO2009 / 096365 Pamphlet

  This invention is made | formed under such a condition, and it aims at providing the inorganic type fiber sheet which can fully exhibit the function of an inorganic particle.

The invention according to claim 1 of the present invention is an inorganic fiber sheet containing inorganic fibers "inorganic particles are collections coagulation through the organic resin, the pore diameter of the inorganic fibers is 1~300nm The feature is an inorganic fiber sheet. "

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The invention according to claim 2 of the present invention is “inorganic fiber sheet according to claim 1, wherein the inorganic fiber has a mass ratio of inorganic particles to organic resin of 50 to 90:50 to 10”. . "
It is.

The invention according to claim 3 of the present invention is “the inorganic fiber sheet according to claim 1, wherein the average fiber diameter of the inorganic fibers is 10 μm or less. Is.

The invention according to claim 4 of the present invention is "the inorganic fiber sheet according to any one of claims 1 to 3 , wherein an average particle diameter of the inorganic particles is 1 µm or less". .

The invention according to claim 5 of the present invention is “the inorganic fiber sheet according to any one of claims 1 to 4 , wherein the porosity of the inorganic fiber sheet is 60% or more.” It is.

In carrying out the present invention, it is preferable that the inorganic fiber is a fiber produced by an electrostatic spinning method, and the solvent used for spinning the inorganic fiber is removed by solvent substitution. is there.

Inorganic fiber sheet according to claim 1 of the present invention, the inorganic particles includes inorganic fibers collecting coagulation through the organic resin, since the inorganic fibers having a pore size of 1~300nm Since not only the inorganic particles constituting the surface of the inorganic fiber but also the inorganic particles constituting the inside of the fiber can be used, the function of the inorganic particles can be sufficiently exhibited.

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Since the inorganic fiber sheet according to claim 2 of the present invention is mainly composed of inorganic particles and has a large amount of inorganic particles, the function of the inorganic particles can be sufficiently exhibited.

In the inorganic fiber sheet according to claim 3 of the present invention, the average fiber diameter of the inorganic fiber is as small as 10 μm or less, and the surface area of the inorganic fiber sheet is large, so that the function of the inorganic particles can be sufficiently exhibited.

In the inorganic fiber sheet according to claim 4 of the present invention, since the average particle diameter of the inorganic particles is as small as 1 μm or less and the surface area of the inorganic fibers is wide, the function of the inorganic particles can be sufficiently exhibited.

Since the inorganic fiber sheet according to claim 5 of the present invention has a void ratio of 60% or more and a large number of voids, and there is little overlap between the inorganic particles, the function of the inorganic particles can be sufficiently exhibited.

In a preferred form of the practice of the present invention, the inorganic fiber sheet is a inorganic fibers produced by electrostatic spinning, and uniform fiber diameter, yet be in a state in which inorganic fibers are uniformly dispersed Therefore, the function of the inorganic particles can be exhibited uniformly.

  The inorganic fiber sheet of the present invention contains inorganic fibers, the inorganic fibers are aggregated with inorganic particles, and the pore diameter of the inorganic fibers is 1 to 300 nm. It can be demonstrated. In other words, by having pores having a diameter of 1 to 300 nm, not only inorganic particles constituting the inorganic fiber surface but also inorganic particles constituting the inside of the inorganic fiber can be used. It can be fully demonstrated.

The inorganic particles constituting the inorganic fiber of the present invention are not particularly limited as long as they are inorganic particles having a desired function. For example, lithium, beryllium, boron, carbon, sodium, magnesium, aluminum, silicon, phosphorus , Sulfur, potassium, calcium, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, arsenic, selenium, rubidium, strontium, yttrium, zirconium, niobium, molybdenum, cadmium, indium , Tin, antimony, tellurium, cesium, barium, lanthanum, hafnium, tantalum, tungsten, mercury, thallium, lead, bismuth, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, te Biumu, dysprosium, may be mentioned holmium, erbium, thulium, ytterbium, or the oxide of lutetium, _{specifically, SiO 2, Al 2 O 3} , B 2 O 3, TiO 2, ZrO 2, CeO 2 FeO, Fe ₃ O ₄ , Fe ₂ O ₃ , VO ₂ , V ₂ O ₅ , SnO ₂ , CdO, LiO ₂ , WO ₃ , Nb ₂ O ₅ , Ta ₂ O ₅ , In ₂ O ₃ , GeO ₂ , PbTi ₄ O ₉ , LiNbO ₃ , BaTiO ₃ , PbZrO ₃ , KTaO ₃ , Li ₂ B ₄ O ₇ , NiFe ₂ O ₄ , SrTiO _{3 and the} like can be mentioned. For example, when an inorganic fiber sheet is used as a heat dissipation material, it is preferably a highly thermally conductive inorganic particle such as α-alumina so as to be excellent in heat dissipation. The inorganic particles may be composed of one component oxide or may be composed of two or more component oxides. For _example, it may be composed of two components of SiO 2 _-Al 2 _{O 3.}

  The average particle diameter of the inorganic particles is not particularly limited, but is preferably 1 μm or less. This is because when the average particle diameter is such, the surface area of the inorganic fiber is large, and the function of the inorganic particles can be sufficiently exhibited. The smaller the average particle size, the greater the surface area of the inorganic fibers and the easier function of the inorganic particles. Therefore, the average particle size is preferably 500 nm or less, more preferably 300 nm or less, and 100 nm or less. Is more preferable. On the other hand, the lower limit of the average particle diameter of the inorganic particles is not particularly limited as long as inorganic fibers can be formed, but is preferably 1 nm or more.

The “average particle diameter (= d)” in the present invention means a value calculated from the following formula (1) from the specific surface area (= S) of the inorganic particles and the density (= ρ) of the inorganic particles. The specific surface area of the inorganic particles is a value measured by a BET method using nitrogen gas, and the density of the inorganic particles is a value measured by a constant volume expansion method. For example, a dry automatic densimeter (Shimadzu Corporation) Manufactured by Accupic II).
d = 6 / (ρS) (1)

In addition, this average particle diameter (= d) is the following formula between the specific surface area (= S), the density (= ρ) and the particle diameter (= d) when the shape of the inorganic particles is a true sphere. Since (2) is established, it is a value calculated with respect to the particle diameter. If the inorganic fiber of the present invention is nano-level inorganic particles capable of forming fine pores having a pore diameter of 1 to 300 nm, inorganic Even if the shape of the particles is not a true sphere, the same tendency is shown, so the average particle diameter is based on the following formula (2) regardless of the shape of the inorganic particles.
S = 6 / (ρd) (2)

  One kind of these inorganic particles may be aggregated, or two or more kinds of inorganic particles that differ in composition and / or average particle diameter may be aggregated.

  The shape of the inorganic particles of the present invention is not particularly limited and can be appropriately selected according to the application of the inorganic fiber sheet. For example, the shape is spherical (substantially spherical or true spherical), fibrous, or needle-shaped. (For example, tetrapot shape), flat plate shape, polyhedron shape, feather shape, and irregular shape. In addition, when using an inorganic type fiber sheet as a heat insulating material, it is more preferable that it is a hollow inorganic particle so that it may be excellent in heat insulation.

  The inorganic fiber of the present invention is a fiber in which the inorganic particles as described above are aggregated and linearly stretched. However, since the pore diameter is 1 to 300 nm, the function of the inorganic particles constituting the inside of the inorganic fiber is also exhibited. can do. If the pore diameter of the inorganic fiber is less than 1 nm, the function of the inorganic particles constituting the inside of the inorganic fiber tends not to be sufficiently exhibited. If the pore diameter exceeds 300 nm, the strength of the fiber decreases, and the fiber sheet Since it becomes difficult to handle, the thickness is preferably 5 to 200 nm, and more preferably 10 to 100 nm. The “pore diameter” in the present invention means an average pore diameter obtained from a Log differential pore volume distribution curve measured by mercury porosimetry. This mercury intrusion method is a method that utilizes the fact that mercury has a large surface tension and that mercury cannot enter the pores unless pressure is applied. For example, a micromeritics automatic porosimeter (registered trademark: Autopore IV9500, Shimadzu) (Manufactured by Seisakusho).

  In addition, the pore volume of the inorganic fiber of the present invention is 0.001 so that the function of the inorganic particles constituting the inside of the inorganic fiber is easily exerted, and it has a certain degree of strength and is easy to handle. It is preferable that it is -0.5mL / g, It is more preferable that it is 0.01-0.5mL / g, It is still more preferable that it is 0.05-0.5mL / g, 0.1-0. More preferably, it is 5 mL / g. This “pore volume” means the cumulative pore volume obtained from the Log differential pore volume distribution curve measured by the mercury intrusion method, as in the method of measuring the pore diameter.

  The inorganic fiber of the present invention is an aggregate of inorganic particles. Only inorganic particles may be agglomerated, but when in an aggregated state via an organic resin, the result is that it is an inorganic fiber that is more flexible and less damaging than the case consisting of only inorganic particles. As an inorganic fiber sheet that is excellent in flexibility and hardly damaged, it is preferable. That is, the organic resin acts as an adhesive that bonds the inorganic particles, and even if an external force is applied to the inorganic fiber sheet, it is flexible and hardly damaged.

  The organic resin is not particularly limited as long as it is interposed between the inorganic particles and can adhere the inorganic particles to each other. For example, polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE), polyfluorinated Vinylidene (PVDF), polyvinyl fluoride (PVF), perfluoroalkoxy fluororesin (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), ethylene / tetrafluoroethylene copolymer (ETFE), ethylene Fluorocarbon resins such as chlorotrifluoroethylene copolymer (ECTFE), vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene copolymer, and copolymers of various monomers constituting the resin; polyethylene (PE) Polyol such as polypropylene (PP) Vinyl resins; Polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); Polyamide resins such as nylon 6 and nylon 66; Acrylics such as polyacrylonitrile, acrylic acid, polyacrylic acid, and polymethacrylic acid Examples thereof include celluloses such as rayon, cellulose such as rayon, polyvinyl alcohol resins, polyurethane, and polyvinylpyrrolidone. In addition, these organic resins may exist independently and 2 or more types of organic resins may exist.

  In addition, when organic resin is interposing between inorganic particles in this way, it is preferable that the mass ratio of inorganic particles and organic resin is 50-90: 50-10. If the inorganic particles are less than 50 mass%, the amount of the inorganic particles is small, and the amount of the organic resin is likely to cover the surface of the inorganic particles, so that the functions of the inorganic particles tend not to be sufficiently exhibited. And it is more preferable that it is 60 mass% or more. On the other hand, when the amount of the inorganic particles exceeds 90 mass%, the amount of the organic resin is relatively reduced, and the flexibility due to the inclusion of the organic resin tends to be insufficient, and is 80 mass% or less. Is more preferable.

  The inorganic fiber of the present invention preferably has an average fiber diameter of 10 μm or less. Thus, when the average fiber diameter of the inorganic fibers is as thin as 10 μm or less, the surface area of the inorganic fiber sheet is large, and the function of the inorganic particles can be sufficiently exhibited, more preferably 8 μm or less. Preferably it is 6 micrometers or less, More preferably, it is 4 micrometers or less. The lower limit of the average fiber diameter is not particularly limited, but is preferably 100 nm or more. The “average fiber diameter” in the present invention means an arithmetic average value of fiber diameters at 50 points, and the “fiber diameter” is a length orthogonal to the direction in which the fibers extend, measured based on a micrograph. Means.

  The inorganic fiber of the present invention can be used effectively so that the fiber does not easily fall off, is excellent in mechanical strength, and can be used effectively for some inorganic particles, such as improved conductivity. It is preferably a substantially continuous fiber. This “substantially continuous fiber” means that the end of the inorganic fiber cannot be confirmed when a 5,000-fold electron micrograph is taken.

  The inorganic fiber of the present invention is preferably a fiber produced by an electrospinning method. Inorganic fibers produced by the electrospinning method have uniform fiber diameters and can be an inorganic fiber sheet in which inorganic fibers are uniformly dispersed, so that the functions of the inorganic particles are uniformly exhibited. Furthermore, it is preferable because it is a substantially continuous fiber, the fiber is difficult to fall off, and is excellent in mechanical strength.

  The inorganic fiber sheet of the present invention contains the inorganic fiber as described above, but preferably accounts for 10 mass% or more in the inorganic fiber sheet so that the function of the inorganic particles can be sufficiently exhibited. %, More preferably 70% or more, still more preferably 90% or more, and most preferably composed of inorganic fibers only.

  The fiber other than the inorganic fiber is not particularly limited as long as it does not hinder the function of the inorganic particles, and can be an organic fiber made of the same organic resin as the organic resin that can form the inorganic fiber. . More specifically, mention may be made of fluorine resin fibers, polyolefin resin fibers, polyester resin fibers, polyamide resin fibers, acrylic resin fibers, cellulose fibers, polyvinyl alcohol resin fibers, polyurethane fibers, polyvinyl pyrrolidone fibers, and the like. Can do. Moreover, inorganic fibers, such as glass fiber and carbon fiber, may be used. In addition, these organic resins and inorganic fibers do not need to be one type, and two or more types may be mixed.

  The inorganic fiber sheet of the present invention contains inorganic fibers, but it is preferable that the inorganic fibers maintain their form by entanglement and / or adhesion. For example, when utilizing the electrical conductivity or thermal conductivity of inorganic particles, it is preferable that the inorganic fiber sheet be bonded so that the electrical conductivity or thermal conductivity is excellent. When used, it is preferable to maintain the form by entanglement so that heat conduction is difficult.

  In the case where the form is maintained by adhesion, the organic resin that acts as an adhesive can be the same organic resin as the organic resin that is interposed between the inorganic particles and can adhere the inorganic particles to each other. That is, it can be fluorine resin, polyolefin resin, polyester resin, polyamide resin, acrylic resin, cellulose, polyvinyl alcohol resin, polyurethane, polyvinyl pyrrolidone, and the like. When inorganic particles are aggregated via an organic resin, the organic resin interposed between the inorganic particles and the organic resin interposed between the inorganic fibers are the same or different. Also good.

The basis weight of the inorganic fiber sheet of the present invention is not particularly limited, but can be ¹ to 300 g / m ² . Moreover, although thickness is not specifically limited, either, it can be 1-1000 micrometers. “Weight” in the present invention is a value obtained by measuring the mass of a sample cut into a 10 cm square and converting it to a mass of 1 m ^2. “Thickness” is a thickness gauge (manufactured by Mitutoyo Corporation: Code No.) .547-401: Measurement force 3.5N or less).

The porosity of the inorganic fiber sheet of the present invention is preferably 60% or more so that the function of the inorganic particles can be sufficiently exerted by having many voids and little overlap between the inorganic particles. % Is more preferable, and 70% or more is still more preferable. On the other hand, it is preferably 95% or less from the viewpoint of form stability. The porosity P (unit:%) is a value obtained from the following formula.
P = 100- (Fr1 + Fr2 + .. + Frn)
Here, Frn shows the filling rate (unit:%) of the component n which comprises an inorganic fiber sheet, and says the value obtained from the following formula | equation.
Frn = [(M × Prn) / (T × SGn)] × 100
Here, M is the basis weight of the inorganic fiber sheet (unit: g / cm ² ), T is the thickness (cm) of the inorganic fiber sheet, and Prn is the component n in the inorganic fiber sheet (for example, inorganic particles, organic resin) And the like, SGn means the specific gravity (unit: g / cm ³ ) of component n, respectively.

Inorganic fiber sheet of the present invention has a wide surface area, so that the function of the inorganic particles can be sufficiently exhibited, it is preferable specific surface area of the inorganic fiber sheet is 1 m 2 ^{/ g} or more, 3m 2 ^/ g More preferably, it is more preferably 5 m ² / g or more.

  This “specific surface area” is a value measured by a BET method using nitrogen gas, and can be measured using, for example, a high-accuracy gas adsorption device (registered trademark: BELSORP, manufactured by Nippon Bell Co., Ltd.).

  In the inorganic fiber sheet of the present invention, the inorganic fibers are uniformly dispersed, and the average pore diameter of the inorganic fiber sheet is 20 μm so that the function of the inorganic particles can be uniformly exhibited throughout the inorganic fiber sheet. Or less, more preferably 15 μm or less, and even more preferably 10 μm or less. The lower limit of the average pore diameter is not particularly limited, but is preferably 0.1 μm or more. This “average pore size” refers to the average flow rate pore size obtained by the bubble point method, and is measured using, for example, a porous material automatic pore size distribution measurement system (registered trademark: Automated Perm Porometer, manufactured by Porous Materials, Inc.). Can do.

  As described above, the inorganic fiber sheet of the present invention aggregates inorganic particles and contains inorganic fibers having pores having a pore diameter of 1 to 300 nm, and therefore can sufficiently exhibit the function of the inorganic particles. For example, when the inorganic particles are titanium dioxide, the photocatalytic performance and catalyst supportability are excellent. When the inorganic particles are aluminum oxide, the thermal conductivity and polishing performance are excellent. When the inorganic particles are silicon dioxide. Is excellent in polishing performance and adsorption performance. Note that, regardless of the type of inorganic particles, the inorganic fibers are porous fibers and thus have excellent performance such as heat insulation. In particular, when the porosity of the inorganic fiber sheet is 60% or more, the heat insulating property is excellent.

  The inorganic fiber sheet of the present invention can be produced, for example, as follows.

  First, spinning is performed using a spinning solution in which inorganic particles and an organic resin are mixed to form inorganic fibers in which inorganic particles are aggregated, and the fiber web is formed by directly collecting and collecting the inorganic fibers. Form. In this way, when inorganic fibers are directly collected and accumulated to form a fiber web, the inorganic fibers are entangled and have a certain strength. If this fiber web has sufficient strength, the fiber web can be used as it is as an inorganic fiber sheet. If this fiber web does not have sufficient strength, or if you want to increase its strength, bond by fluid entanglement, plasticization of organic resin with solvent, fusion of organic resin with heat, adhesion with adhesive, etc. And it can be set as an inorganic fiber sheet.

  In addition, when the mass ratio of the inorganic particles and the organic resin (solid content) in the spinning solution is 50 to 90:50 to 10, the organic resin is interposed between the inorganic particles, and the inorganic particles are likely to be aggregated. This is preferable because the function of the particles can be sufficiently exhibited.

  In addition, when inorganic particles are aggregated by applying a coupling treatment to the inorganic particles, the pore volume in the inorganic fibers can be increased. Therefore, when used for applications that require heat insulation, etc. Is preferred.

  The solid content concentration of the spinning solution is not particularly limited as long as spinning can be performed. The solvent constituting the spinning solution is not particularly limited as long as it can disperse inorganic particles and can dissolve or disperse an organic resin. For example, water; alcohol ( Organic solvents such as methanol, ethanol, etc., N, N-dimethylformamide, N, N-dimethylacetamide or N-methyl-2-pyrrolidone can be used alone or in admixture.

  The fibers constituting the fiber web formed by directly collecting and accumulating the spun inorganic fibers are preferably continuous fibers. This is because the continuous fibers are less likely to drop off and are excellent in mechanical strength.

  In addition, as a method for forming a fiber web, for example, an electrostatic spinning method, a spunbond method, a melt blow method, or a spinning solution discharged from a liquid discharge unit as disclosed in JP-A-2009-287138 is used. On the other hand, there can be mentioned a method in which gas is discharged in parallel and a fiber is formed by applying a shearing force to the spinning solution in a straight line. The electrostatic spinning method or the method disclosed in Japanese Patent Application Laid-Open No. 2009-287138 is preferable because an average fiber diameter of 10 μm or less is easy to manufacture, and particularly, according to the electrostatic spinning method, the fiber diameters are uniform. In addition, it is preferable because an inorganic fiber sheet can be produced in which the inorganic fibers are uniformly dispersed and the function of the inorganic particles can be exhibited uniformly.

  In addition, when using a spinning solution in which inorganic particles are mixed in a solution in which an organic resin is dissolved in a solvent, as in the electrostatic spinning method or the method disclosed in JP2009-287138A, the solvent is volatilized during spinning. After forming a fiber web or non-woven fabric using a material that is difficult to resist, the organic resin is plasticized when the solvent is removed by solvent replacement, and the inorganic fibers are easily bonded to each other by the organic resin, and have excellent mechanical strength. Easy to manufacture fiber sheets.

  In addition, after winding the inorganic fiber as a continuous fiber and then cutting the inorganic fiber into a desired fiber length to make a short fiber, a fiber web is formed by a known dry method or wet method, and entangled by a fluid flow or the like The inorganic fiber sheet can be made by bonding by plasticizing the organic resin with a solvent, fusing the organic resin with heat, bonding with an adhesive, or the like. However, as described above, since the inorganic fiber is preferably a continuous fiber, it is preferable to produce an inorganic fiber sheet from a fiber web formed by collecting and accumulating continuous inorganic fibers directly.

  Examples of the present invention will be described below, but the present invention is not limited to the following examples.

  The “fiber diameter” of the inorganic fiber constituting the inorganic fiber sheet is measured based on a photograph (5000 times) taken with a scanning electron microscope (registered trademark: Miniscope TM3030, manufactured by Hitachi High-Tech), and is inorganic. The “pore diameter” of the fiber is measured with a micromeritics automatic porosimeter (registered trademark: Autopore IV9500, manufactured by Shimadzu Corporation), and the “specific surface area” of the inorganic fiber sheet is a high-accuracy gas adsorption device (registered trademark: BELSORP, (Made by Nippon Bell). Furthermore, “pore volume” was measured with a micromeritics automatic porosimeter [Autopore IV9500, manufactured by Shimadzu Corporation].

Example 1
Silica particles having an average particle diameter of 7 nm (grade: R812, manufactured by Nippon Aerosil Co., Ltd.) were converted into a vinylidene fluoride / tetrafluoroethylene / hexafluoropropylene copolymer solution (hereinafter referred to as “FTH resin”, solid content concentration: 10%, solvent) : N, N-dimethylformamide) and stirring with a stirrer for 30 minutes (rotation speed: 2000 rpm), and then spinning an inorganic fiber containing 60 mass% of silica particles by the electrostatic spinning method under the following spinning conditions. Inorganic fibers consisting of silica continuous fibers that are directly collected and accumulated and silica particles are aggregated via FTH resin, in which the silica continuous fibers are intertwined with each other and bonded via FTH resin A sheet was produced. The physical properties of this inorganic fiber sheet were as shown in Table 1.

(Spinning conditions)
・ Discharge amount from nozzle: 4.0 g / hour ・ Distance between nozzle tip and drum collector: 10 cm
・ Temperature and humidity in spinning container: 25 ℃ / 35% RH
・ Applied voltage to nozzle: + 10kV

(Example 2)
Silica particles having an average particle diameter of 7 nm (grade: R812, manufactured by Nippon Aerosil Co., Ltd.) are mixed with an FTH resin solution (solid content concentration: 10%, solvent: N-methyl-2-pyrrolidinone) and stirred with a stirrer for 30 minutes ( Then, inorganic fibers containing 80 mass% of silica particles were spun by the electrostatic spinning method under the following spinning conditions, and directly collected and accumulated to form a precursor inorganic fiber sheet.

  Thereafter, the solvent is extracted by immersing the precursor inorganic fiber sheet in water for 30 minutes, and the silica particles are composed only of the silica-based continuous fibers aggregated via the FTH resin, and the silica-based continuous fibers are intertwined. At the same time, an inorganic fiber sheet bonded through an FTH resin was produced. The physical properties of this inorganic fiber sheet were as shown in Table 1.

(Spinning conditions)
・ Discharge amount from nozzle: 4.0 g / hour ・ Distance between nozzle tip and drum collector: 10 cm
・ Temperature and humidity in spinning container: 25 ℃ / 40% RH
・ Applied voltage to nozzle: + 10kV

(Example 3)
Alumina particles having an average particle diameter of 13 nm (grade: C805, manufactured by Nippon Aerosil Co., Ltd.) are mixed with FTH resin solution (solid content concentration: 10%, solvent: N, N-dimethylformamide), and stirred (rotated) for 30 minutes with a stirrer. Number: 2000 rpm), and then the inorganic fiber containing 50 mass% of alumina particles is spun by the electrospinning method under the following spinning conditions, directly collected and accumulated, and the alumina particles are aggregated via the FTH resin. An inorganic fiber sheet made of only continuous fibers and having alumina continuous fibers intertwined and bonded via an FTH resin was produced. The physical properties of this inorganic fiber sheet were as shown in Table 1.

(Spinning conditions)
・ Discharge rate from nozzle: 2.0 g / hour ・ Distance between nozzle tip and drum collector: 10 cm
・ Temperature and humidity in spinning container: 25 ℃ / 40% RH
・ Applied voltage to nozzle: + 10kV

Example 4
Titania particles (grade: T805, manufactured by Nippon Aerosil Co., Ltd.) having an average particle diameter of 21 nm are mixed with FTH resin solution (solid content concentration: 10%, solvent: N, N-dimethylformamide), and stirred (rotated) for 30 minutes with a stirrer. Number: 2000 rpm) and then spinning the inorganic fiber containing 50 mass% of titania particles by the electrospinning method under the following spinning conditions, directly collecting and collecting the titania particles, and the titania particles aggregated via the FTH resin. The inorganic fiber sheet which consisted only of the system continuous fiber, and in which the titania system continuous fiber was intertwined, and adhere | attached via FTH resin was manufactured. The physical properties of this inorganic fiber sheet were as shown in Table 1.

(Spinning conditions)
・ Discharge rate from nozzle: 2.0 g / hour ・ Distance between nozzle tip and drum collector: 10 cm
・ Temperature and humidity in spinning container: 25 ℃ / 40% RH
・ Applied voltage to nozzle: + 10kV

(Example 5)
Hollow nanosilica having an average particle size of 100 nm (product name: Sirinax (registered trademark), manufactured by Nittetsu Mining) is mixed with FTH resin solution (solid content concentration: 10%, solvent: N, N-dimethylformamide) and stirred. After stirring for 30 minutes in the machine (rotation speed: 2000 rpm), inorganic fibers containing 50 mass% of hollow nanosilica particles are spun by the electrospinning method under the following spinning conditions, directly collected and collected, and hollow nanosilica particles Made of only the silica-based continuous fibers aggregated through the FTH resin, and the silica-based continuous fibers were intertwined with each other, and an inorganic fiber sheet bonded through the FTH resin was produced. The physical properties of this inorganic fiber sheet were as shown in Table 1.

(Spinning conditions)
・ Discharge rate from nozzle: 2.0 g / hour ・ Distance between nozzle tip and drum collector: 10 cm
・ Temperature and humidity in spinning container: 25 ℃ / 40% RH
・ Applied voltage to nozzle: + 10kV

(Example 6)
Silica particles (grade: R812, manufactured by Nippon Aerosil Co., Ltd.) having an average particle diameter of 7 nm are mixed with polyacrylonitrile (hereinafter referred to as “PAN resin”, solid content concentration: 16%, solvent: N, N-dimethylformamide). After stirring with a stirrer for 30 minutes (rotation speed: 2000 rpm), inorganic fibers containing 50 mass% of silica particles are spun by the electrospinning method under the following spinning conditions, and are directly collected and accumulated to form a precursor inorganic A fiber sheet was formed.

  Thereafter, the solvent is extracted by immersing the precursor inorganic fiber sheet in water for 30 minutes, and the silica particles are composed only of the silica-based continuous fibers aggregated via the PAN resin, and the silica-based continuous fibers are intertwined. At the same time, an inorganic fiber sheet bonded through a PAN resin was produced. The physical properties of this inorganic fiber sheet were as shown in Table 1.

(Spinning conditions)
・ Discharge rate from nozzle: 2.0 g / hour ・ Distance between nozzle tip and drum collector: 10 cm
・ Temperature and humidity in spinning container: 25 ℃ / 40% RH
・ Applied voltage to nozzle: + 10kV

(Example 7)
Silica particles having an average particle diameter of 7 nm (grade: R812, manufactured by Nippon Aerosil Co., Ltd.) are mixed with FTH resin solution (solid content concentration: 10%, solvent: N, N-dimethylformamide), and stirred (rotated) for 30 minutes with a stirrer. (Number: 2000 rpm), and then the inorganic fiber containing 40 mass% of silica particles is spun by the electrostatic spinning method under the following spinning conditions, directly collected and accumulated, and the silica particles are aggregated via the FTH resin. The inorganic type fiber sheet which consisted only of the system continuous fiber, and the silica system continuous fiber was intertwined, and adhere | attached via FTH resin was manufactured. The physical properties of this inorganic fiber sheet were as shown in Table 1.

(Spinning conditions)
・ Discharge amount from nozzle: 4.0 g / hour ・ Distance between nozzle tip and drum collector: 10 cm
・ Temperature and humidity in spinning container: 25 ℃ / 35% RH
・ Applied voltage to nozzle: + 10kV

(Comparative Example 1)
Fe ₃ O ₄ aqueous dispersion colloid (product name: EMG607, product name: EMG607, average particle size: about 10 nm, solid content: about 10 mass%) whose particle surface is covered with a cationic surface modifier is added to polyvinyl pyrrolidone (manufactured by Aldrich, Mw: about 1,300,000, solvent: mixed solvent of ethanol and water 1: 1) and mixed so that the composite iron oxide amount becomes 33.3 mass% of the total solid content, and stirred for 30 minutes with a stirrer ( (Rotation speed: 2000 rpm) After that, an attempt was made to spin by an electrostatic spinning method under the following spinning conditions, but spinning could not be performed.

(Spinning conditions)
・ Discharge rate from nozzle: 0.5 g / hour ・ Distance between nozzle tip and drum collector: 18 cm
・ Temperature and humidity in spinning container: 25 ℃ / 20% RH
・ Applied voltage to the nozzle: + 14.5kV

(Comparative Example 2)
Fe ₃ O ₄ aqueous dispersion colloid (manufactured by Ferrotec, trade name: EMG607, average particle size: about 10 nm, solid content: about 10 mass%) covered with a cationic surface modifier on the particle surface was added to polyvinyl pyrrolidone (hereinafter, “ “PVP resin”, made by Aldrich, Mw: about 1,300,000, solvent: mixed solvent of ethanol and water 1: 1), so that the composite iron oxide amount is 9.1 mass% of the total solid content After mixing and stirring with a stirrer for 30 minutes (rotation speed: 2000 rpm), fibers containing 9.9 mass% of iron oxide particles are spun by the electrospinning method under the following spinning conditions, and directly collected and collected. A fiber sheet in which iron oxide particles are dispersed in a PVP resin and made only of iron oxide-containing continuous fibers, and the iron oxide-containing continuous fibers are intertwined with each other and bonded via the PVP resin. It was produced. The physical properties of this fiber sheet were as shown in Table 1.

(Spinning conditions)
・ Discharge rate from nozzle: 0.5 g / hour ・ Distance between nozzle tip and drum collector: 18 cm
・ Temperature and humidity in spinning container: 25 ℃ / 20% RH
・ Applied voltage to the nozzle: + 14.5kV

(Comparative Example 3)
Silica particles having an average particle diameter of 7 nm (grade: R812, manufactured by Nippon Aerosil Co., Ltd.) are mixed with FTH resin solution (solid content concentration: 10%, solvent: N, N-dimethylformamide), and stirred (rotated) for 30 minutes with a stirrer. (Number: 2000 rpm), and then the inorganic fiber containing 30 mass% of silica particles is spun by electrostatic spinning under the following spinning conditions, directly collected and accumulated, and the silica particles are aggregated via FTH resin. The inorganic type fiber sheet which consisted only of the system continuous fiber, and the silica system continuous fiber was intertwined, and adhere | attached via FTH resin was manufactured. The physical properties of this inorganic fiber sheet were as shown in Table 1.

(Spinning conditions)
・ Discharge amount from nozzle: 4.0 g / hour ・ Distance between nozzle tip and drum collector: 10 cm
・ Temperature and humidity in spinning container: 25 ℃ / 35% RH
・ Applied voltage to nozzle: + 10kV

  From Example 1, Example 7 and Comparative Example 3, when the amount of the inorganic particles is 40 mass% or more, the inorganic particles have pores of 1 nm or more, and the function of the inorganic particles inside the inorganic fiber can be exhibited. When the amount of particles is 50 mass% or more, the pore volume is 0.1 mL / g or more, which is a porous inorganic fiber, and it can be estimated that this is an inorganic fiber sheet capable of maximizing the function of the inorganic particles. .

  From Examples 3 and 4, it can be estimated that the inorganic fiber sheet has pores of 1 nm or more and can also function as inorganic particles inside the inorganic fiber regardless of the type of inorganic particles.

  From Example 1 and Example 6, when the solvent is extracted, an inorganic fiber sheet having a larger pore solution can be obtained, and the inorganic fiber sheet can exhibit the function of inorganic particles inside the inorganic fiber more. I was able to estimate.

  Since the inorganic fiber sheet of the present invention can sufficiently exhibit the function of the inorganic particles, the application requires photocatalytic performance, catalyst supportability, thermal conductivity, polishing performance, adsorption performance, etc. according to the inorganic particles. Can be used. In addition, since it has a pore irrespective of the kind of inorganic particle, it is excellent in heat insulation.

Claims (5)

Inorganic particles are inorganic fiber sheet containing inorganic fibers collecting coagulation through the organic resin, wherein the pore diameter of the inorganic fibers is 1 to 300 nm, the inorganic fiber sheet. The inorganic fiber sheet according to claim 1 , wherein the inorganic fiber and the organic resin are inorganic fibers having a mass ratio of 50 to 90:50 to 10 . The inorganic fiber sheet according to any one of claims 1 and 2, wherein an average fiber diameter of the inorganic fibers is 10 µm or less. The inorganic fiber sheet according to any one of claims 1 to 3 , wherein the average particle diameter of the inorganic particles is 1 µm or less. The inorganic fiber sheet according to any one of claims 1 to 4 , wherein the porosity of the inorganic fiber sheet is 60% or more.