WO2004080916A1 - 無機質多孔体及びその製造方法 - Google Patents
無機質多孔体及びその製造方法 Download PDFInfo
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- WO2004080916A1 WO2004080916A1 PCT/JP2004/003088 JP2004003088W WO2004080916A1 WO 2004080916 A1 WO2004080916 A1 WO 2004080916A1 JP 2004003088 W JP2004003088 W JP 2004003088W WO 2004080916 A1 WO2004080916 A1 WO 2004080916A1
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
- C04B38/0051—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof characterised by the pore size, pore shape or kind of porosity
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- the present invention relates to an inorganic porous material and a method for producing the same.
- the present invention relates to an inorganic porous body and a method for producing the same. More specifically, an inorganic porous material having a pore structure composed of interconnected pores and having a small pressure loss when gas is permeated, or an inorganic material having a pore structure composed of independent pores and having a small thermal conductivity Porous materials, all of which have a low coefficient of thermal expansion and excellent mechanical strength, are easy to adjust the size and shape of the pore structure, have a low environmental load, are simple and low cost.
- the present invention relates to a method for producing an inorganic porous body capable of producing an inorganic porous body. Background art
- an inorganic porous body having a pore structure (three-dimensional network structure and / or sponge-like structure) is mainly composed of a metal oxide (ceramic) such as alumina.
- a metal oxide ceramic
- These inorganic porous materials were produced, for example, by the following method.
- a method of impregnating a slurry-like ceramic raw material with a foam-like organic material such as polyurethane foam, drying, degreasing and sintering the impregnated material and burning off the foam-like organic material for example, Patent Document 1.
- Air bubbles are introduced into a slurry composed of alumina and an organic binder to form a bubble-containing slurry, and the organic binder is gelled, dried, degreased, and sintered to form an inorganic material.
- a method for obtaining a porous body for example, see Patent Documents 2 and 3).
- Non-Patent Document 1 A method for obtaining an inorganic porous material by foaming a mixed system composed of colloidal silica, a surfactant, methanol and a blowing agent (for example, fluorocarbon gas) by evaporating the blowing agent, and then gelling to obtain an inorganic porous material.
- a blowing agent for example, fluorocarbon gas
- the silica precursor and the surfactant are mixed, and the catalyst is mixed.
- a method comprising the steps of forming a foam-like hydrous silica having a foam structure maintained by immobilizing the foam structure by polymerization, and drying the obtained foamed hydrous silica having the obtained foam structure ( See Patent Document 4). '
- Patent Document 3 Patent Document 3
- Patent Document 4 Patent Document 4
- each of these conventional inorganic porous bodies has the following problems.
- the methods [1] and [2] have a problem in that degreasing is difficult and, in addition, emit carbon dioxide gas as organic matter is burned off, and thus have a problem in terms of environmental protection.
- the method [3] has a problem in terms of environmental protection, such as destruction of the ozone layer, since fluorocarbon gas or the like is used as a foaming agent.
- the method [4] has a problem that the raw materials used are expensive. Disclosure of the invention
- An inorganic porous body and a method of manufacturing the same according to the present invention have been made in view of the above-described problems, and have a pore structure including communicating pores, and have a small pressure loss when gas is permeated.
- a method for producing an inorganic porous material which is excellent in the degree of production, and in which the size and shape of the pore structure can be easily adjusted, the load on the environment is small, and the inorganic porous material can be produced easily and at low cost. The purpose is to:
- the present invention has been made to achieve the above object, and the present invention provides the following inorganic porous body and a method for producing the same.
- An inorganic porous material having a pore structure (a three-dimensional network structure and a z- or sponge-like structure) composed of a large number of interconnected pores, at least a part of which is spherical, wherein the pores forming the pore structure are provided. Having a size of 5 m to 2 mm, a porosity of 60% or more, and a gas permeability coefficient of 1 ⁇ 10—nm 2 or more (hereinafter referred to as “first Inorganic porous body ").
- Silica S I_ ⁇ 2
- titania T I_ ⁇ 2
- cordierite Mg 2 A 1 4 S i 5 0 18
- mullite 3 A 1 2 03 ⁇ 2 S I_ ⁇ 2)
- Fuorusu Teraito M g 2 S i 0 4
- inorganic porous material according to the mainly composed of at least one of Bareru selected from the group consisting of aluminum titanate (a 1 2 T i 0 5 ) [1].
- the porosity is 60% or more, and the ratio of the spherical pores among the pores forming the pore structure ((volume of spherical pores Z volume of all pores) XI 00) is
- An inorganic porous material characterized by having a thermal conductivity of not more than 60% and a thermal conductivity of not more than 0.07 W / mK hereinafter sometimes referred to as “second inorganic porous material”).
- the metal oxide sol and / or metal hydroxide sol, the first surfactant, and the first pH adjuster are adjusted to have a pH such that the viscosity is 100 to 20,000 mPa's.
- the raw material sol having a predetermined gelation time is prepared by mixing under the conditions of temperature and temperature, and the obtained raw material sol is mechanically stirred to form a sol porous body into which bubbles are introduced.
- the sol porous body obtained is heated at a predetermined temperature as needed to gel, thereby forming a gel porous body, and drying the obtained gel porous body to form a dried gel porous body.
- a method for producing an inorganic porous material, which comprises heat-treating the obtained dried gel porous material hereinafter, may be referred to as a “first production method”).
- the gel porous body is dried to form the dried gel porous body, and when the obtained dried gel porous body is subjected to heat treatment, the gel porous body is kept at a temperature and a humidity while maintaining the temperature and humidity. And aging to form an aged gel porous body.
- the obtained aged gel porous body is pre-dried at a reduced humidity while maintaining the temperature to form a pre-dried gel porous body.
- the method for producing an inorganic porous material according to [7] wherein the pre-dried porous gel is dried to form the dry porous gel, and the obtained dried porous gel is heat-treated.
- the metal oxide sol and / or metal hydroxide sol, the second surfactant, and the second pH adjuster have a viscosity of 100 to 20000 mPa's.
- the mixture is mixed under conditions of pH and temperature to prepare a raw material sol having a predetermined gelation time, and on the other hand, at least one selected from the group consisting of metal oxides, metal hydroxides and metal carbonates
- a raw material powder preparation containing a kind of raw material powder is prepared, and the obtained raw material sol and the raw material powder preparation are mixed, and then mechanically stirred to obtain a powder-containing sol into which bubbles are introduced.
- a porous body is formed, and the obtained powder-containing sol porous body is required.
- the powdered gel-containing porous body is dried by heating at a predetermined temperature if necessary to form a gel, and the powder-containing porous gel body is dried to form a dry powder-containing porous gel body.
- a method for producing an inorganic porous material which comprises heat-treating the dried powder-containing gel porous material (hereinafter, also referred to as a “second production method”).
- a powder slurry containing at least one kind of the raw material powder selected from the group consisting of a metal oxide, a metal hydroxide, and a metal carbonate, a third surfactant The raw material slurry according to [11], wherein the raw material slurry is prepared by mixing the raw material powder with a pH adjuster under the condition that the raw material powder has a concentration of 1% by weight or more and the same pH as the raw material sol.
- the method for producing an inorganic porous material according to the above.
- the powder-containing gel porous material is dried to form the dry powder-containing gel porous material, and when the obtained dry powder-containing gel porous material is subjected to heat treatment, the powder-containing gel porous material is dried.
- the mixture is aged while standing while maintaining the temperature and humidity to form an aged powder-containing porous gel body.
- the obtained aged powder-containing gel porous body is preliminarily dried by lowering the humidity while maintaining the temperature. Forming a pre-dried powder-containing gel porous body, drying the pre-dried powder-containing gel porous body to form the dry powder-containing gel porous body, and heat-treating the obtained dry powder-containing gel porous body.
- the method for producing an inorganic porous material according to the above [11] or [12].
- the metal oxide sol and / or the metal hydroxide sol is a silica (Si 2 ) sol and / or a titania (T i 0 2 ) sol, and the metal oxide and the metal hydroxide (S i), titanium (T i), aluminum (A 1), and alkaline earth metal are at least one kind of raw material powder selected from the group consisting of
- an inorganic porous material having a pore structure composed of interconnected pores and having a small pressure loss when gas is permeated or an inorganic porous material having a pore structure composed of independent pores and having a small thermal conductivity And have a low coefficient of thermal expansion
- FIG. 1 is a photograph showing the result of observing the pore structure of the siliceous porous material obtained in Example 1 of the present invention with a scanning electron microscope.
- FIG. 2 is a photograph showing the result of observing the pore structure of the siliceous porous material obtained in Example 2 of the present invention with a scanning electron microscope.
- FIG. 3 is a photograph showing the result of observing the pore structure of the siliceous porous material obtained in Example 3 of the present invention with a scanning electron microscope.
- FIG. 4 is a photograph showing the result of observing the pore structure of the porous porous body obtained in Example 4 of the present invention with a scanning electron microscope.
- FIG. 5 is a photograph showing the results of observing the pore structure of the porous porous body obtained in Example 5 of the present invention with a scanning electron microscope.
- FIG. 6 is a photograph showing the result of observing the pore structure of the titania porous body obtained in Example 6 of the present invention with a scanning electron microscope.
- FIG. 7 is a photograph showing the result of observing the pore structure of the porous porous body obtained in Example 7 of the present invention with a scanning electron microscope.
- FIG. 8 is a photograph showing the result of observing the pore structure of the cordierite porous body obtained in Example 9 of the present invention with a scanning electron microscope.
- FIG. 9 is a photograph showing the result of observing the pore structure of the siliceous porous material obtained in Comparative Example 1 of the present invention with a scanning electron microscope.
- the inorganic porous body of the present invention is an inorganic porous body having a pore structure (a three-dimensional network structure and a Z or sponge-like structure) composed of a large number of pores, at least a part of which is spherical, and forms a pore structure.
- the pore size is 5 ⁇ m ⁇ 2 mm and the porosity is more than 60%.
- shea silica (S i 0 2), titania (T I_ ⁇ 2), cordierite (Mg 2 A 1 4 S i 5 0 18), mullite (3 A 1 2 ⁇ 3 ⁇ 2 S I_ ⁇ 2), rather low is selected from the group consisting of Fuorusu Te write (Mg 2 S i O 4) and aluminum titanate (A l 2 T I_ ⁇ 5) preferably one with, as the main component of the second inorganic porous material, silica (S i 0 2), titania (T i 0 2), co one cordierite (Mg 2 a 1 4 S i 5 0 18) , mullite (3A l 2 ⁇ 3 '2 S I_ ⁇ 2), one preferably at least selected from the group consisting of Fuorusu Te write (Mg 2 S i 0 4) and aluminum titanate (A 1 T i 0 5) .
- Silica (S i 0 2), titania (T i 0 2), Kojiera site (Mg 2 A l 4 S i 5 ⁇ ls), mullite (3 A 1 2 0 3 ⁇ 2 S i 0 2), Fuoru Stellite ( mg 2 S I_ ⁇ 4) is not particularly limited to the aluminum titanate (a 1 2 T i 0 5 ), for some of the polymorph as crystal phase, and thermal expansion characteristics, from the viewpoint of catalytic properties, in the case of silica (S i 0 2) are those of amorphous, in the case of titania (T I_ ⁇ 2), anatase, in the case of aluminum titanate (a l 2 T I_ ⁇ 5) Examples of suitable examples include a low-temperature type (iS phase).
- cordierite Mg 2 A l 4 S i 5 ⁇ 1 [delta]
- fin Deer write a polymorph (chemical composition is the same but that have different crystal structures). These may be used alone or as a mixture of two or more.
- the first inorganic porous material of the present invention has a pore structure (a three-dimensional network structure and / or a sponge-like structure) composed of a large number of interconnected pores, at least a part of which is spherical.
- the size of the pores should be 5 .m to 2 mm. If it is less than 5 nm, the gas permeability coefficient will be small (when gas is permeated, the pressure loss will be high), and if it exceeds 2 mm, the strength will be small. Further, the first inorganic porous material of the present invention needs to have a porosity of 60% or more. If the porosity is less than 60% ', the gas permeability coefficient decreases (when gas is permeated, the pressure loss increases). The gas permeability coefficient needs to be 1 X 1 O m 2 or more.
- the second inorganic porous body of the present invention has a pore structure (sponge-like structure) composed of a large number of independent pores, at least a part of which is spherical.
- the size of this pore is It must be between 5 m and 2 mm. There is no problem in properties even if it is less than 5 im, but the amount of surfactant used to stabilize the foam increases, the burden on the environment increases, and if it exceeds 2 mm, the mechanical strength is low become. Further, the porosity needs to be 60% or more as in the case of the first inorganic porous body.
- the proportion of spherical pores in the pores forming the pore structure ((volume of spherical pores, volume of all pores) XI 00) must be 60% or more. If it is less than 60%, the thermal conductivity will be high. The thermal conductivity must be less than 0.07W / mK.
- the first inorganic porous material and the second inorganic porous body of the present invention to minutes main component Siri force, the thermal expansion coefficient of 2 X 1 (gamma 6 K-1 or less, the bending strength is higher IMP a in is preferable.
- thermal expansion coefficient is more than 2 X 10- 6 K- 1, which may cause problems in thermal shock resistance.
- the flexural strength is less than 1 MP a, as a structural material It may not be used or may cause a problem in thermal shock resistance.
- the first inorganic porous material and the second inorganic porous material of the present invention is mainly composed Kojerai preparative (Mg 2 A 1 4 S i 5 ⁇ 18), the thermal expansion coefficient of 2. 2 X 1 O ⁇ K "1 or less, it is preferable bending strength is 0. 5 ⁇ a more. coefficient of thermal expansion, 2. more than 2 X 10- 6 K-1 If there is causing problems in thermal shock resistance. the If the flexural strength is less than 0.5 MPa, it may not be used as a structural material, or a problem may occur in thermal shock resistance.
- the first inorganic porous body of the present invention has a small thermal expansion coefficient, on the superior flexural strength, gas permeability coefficient as large as 1 X 1 O ⁇ m 2 or more, if allowed to transmit gases, the pressure loss Since it can be reduced, it is preferably used for applications such as fill and fill.
- the second inorganic porous material of the present invention has a small coefficient of thermal expansion, excellent bending strength, a low thermal conductivity of 0.07 W / mK or less, and excellent heat insulating properties, and thus is suitable for applications such as heat insulating materials. Used for
- the method for producing an inorganic porous material of the present invention comprises: a metal oxide sol and / or a metal hydroxide sol; a first surfactant; and a first PH regulator.
- the raw material sol having a predetermined gelation time is prepared by mixing under conditions of pH and temperature so that the viscosity becomes 100 to 20,000 mPas, and the obtained raw material sol is mechanically mixed.
- the resultant porous sol is heated at a predetermined temperature to form a gel, and the resultant porous gel is formed. Is dried to form a dried gel porous body, and the obtained dried gel porous body is subjected to a heat treatment.
- first manufacturing method first, as a metal oxide sol and / or metal hydroxide zone le (preferred embodiment, silica (S i 0 2) sol, Ru cited Chita ⁇ A (T I_ ⁇ 2) sol ), A first surfactant, and a first pH adjuster, at a pH and temperature such that the viscosity is 100 to 200 mPas.
- a raw material sol having a predetermined gelation time is prepared.
- silica (S i 0 2) sol and / or titania (T i 0 2) will be described using the sol.
- silica (S i 0 2) sol and / or titania (T i 0 2) sol, solvent (water) to the sol particles is monodispersed In this state, it is often used for various purposes. For this reason, it is devised that the monodispersed state can be stably maintained for a long time.
- the driving force for gelling the sol can be obtained by creating a state in which the sol is likely to aggregate.
- the addition of the first pH adjuster promotes gelation by the action of [1] (and in some cases also [4]), and heating adds the action of [2]. Respectively, to promote gelation.
- the time-dependent change in the viscosity of the raw material sol is forcibly accelerated (the raw material sol becomes In the first production method, a method that controls pH and temperature is used as a method for controlling the gelation of the gel.
- the pH of a normal silica sol is about 10 (the pH of a titania sol is about 1), but the gelation (viscosity) is achieved by controlling the pH of the raw material sol to 5 to 7 (the pH of a titania sol is 2 to 4).
- the time is several tens of mPa ⁇ s.) The time is several minutes to several hours. Also, increasing the temperature increases the gel time (the gel time decreases inversely with temperature).
- the gelation time is about 40 to 60 minutes at a temperature of 20, but about 40 to 40 minutes at 40 ° C, 10 to 30 minutes. About.
- gelation can be promoted at 20 ° C, and then rapidly heated to 40 ° C to cause gelation.
- the gelation time controlled by the above-described method is usually preferably from 1 minute to 1 hour, and more preferably from several minutes to several tens of minutes from the viewpoint of operation.
- the temperature may be changed after introducing air bubbles into the raw material sol to form pores.
- the pore structure can be instantaneously gelled while maintaining the state at the time of formation, and the shape and size of the pores constituting the pore structure can be easily controlled.
- the viscosity of the raw material sol at the time of introducing bubbles to be described later is important to adjust to a range of 100 to 20000 mPa's. As long as the viscosity of the raw material sol can be in such a range, it can be appropriately combined.
- the silica (S i ⁇ 2 ) sol and / or titania (T i ⁇ 2 ) sol used in the first production method are not particularly limited as long as they can gel under predetermined conditions.
- those having an average particle diameter of 10 nm and a concentration of 30% can be mentioned as a preferable example.
- Silica (S i 0 2) sol and titania (T I_ ⁇ 2) may be used either alone of sol, it may be used a mixture of two or more.
- silica The concentration of (S i 0 2 ) sol and titania (T i 0 2 ) sol may be any commercially available concentration, but if it is too thin, the mechanical strength after gelation is low, and Since it is difficult to maintain, 20% or more is preferable.
- the first surfactant used in the first production method has a high foaming property and is capable of forming stable pores by introducing bubbles into the obtained raw material sol. It may be any of anionic, anionic, cationic, nonionic and amphoteric, but a linear surfactant is preferred. Further, a nonionic one which does not affect pH is preferable. Further, a material containing no alkali metal or the like is preferable so that no impurities remain after the calcination.
- anionic surfactants fatty acid salts, alkyl sulfate salts, polyoxyethylene alkyl ether sulfate salts, alkyl benzene sulfonates, alkyl naphthalene sulfonates, alkyl sulfosuccinates, alkyl diphenyl ethers Disulfonates, alkyl phosphates and polycarboxylates can be mentioned.
- an aliphatic quaternary ammonium salt having a higher alkyl group and a lower alkyl group such as hexadecylcetyl trimethylammonium chloride
- an aliphatic amine salt having a higher alkyl group and a lower alkyl group are used.
- the nonionic surfactant include polyoxyethylene alkyl ether having a higher alkyl group and an oxetylene group, polyxethylene alcohol ether obtained by addition-polymerizing ethylenoxide to a higher alcohol, and glycerin monofatty acid.
- the first pH adjuster used in the first production method is not particularly limited, and examples thereof include acids such as hydrochloric acid, nitric acid, sulfuric acid, and acetic acid (which may be inorganic acids and organic acids. Or bases such as aqueous ammonia, sodium hydroxide, calcium hydroxide, etc. I can do it. Among them, it is preferable to use hydrochloric acid, ammonia water, or the like from the viewpoint of reducing the gelation time for the operation.
- the viscosity of the raw material sol reaches a desired value in the range of 100 to 20000 mPa ⁇ s
- the raw material sol is mechanically stirred, and the sol into which bubbles are introduced. Form a porous body.
- the shape and size of the pores constituting the pore structure of the obtained inorganic porous material can be controlled by the timing of introducing the bubbles (the viscosity of the raw material sol at the time of introduction). As the viscosity of the raw material sol is lower, interconnected pores in which a thin skeleton forms a three-dimensional structure are more likely to be generated, and as the viscosity of the raw material sol is higher, independent pores are more likely to be formed.
- the viscosity of the raw material sol can be appropriately selected from the range of 100 to 20000 mPa * s, and if it is less than 10 OmPas, it is faster than the gelation speed and the pore structure It is difficult to obtain a uniform pore structure as a whole, and if it exceeds 2000 OmPa ⁇ s, it becomes difficult to stir for introducing bubbles.
- a range of 100 to 100 OmPa * s is selected as the viscosity of the raw material sol.
- the viscosity of the raw material sol is 1000 to 2000 OmPas. It is preferable to select a range.
- Air taken into the raw material sol by mechanical agitation is covered with the raw material sol film and becomes bubbles to form pores (form porous sols). And plays a role to make it exist stably.
- the method of mechanically stirring is not particularly limited, and examples thereof include mechanical stirring with a stirrer (mixer), a whitper, a foaming machine, and the like. Also, bubbles may be introduced by gas injection or the like.
- the stirring time is not particularly limited, but is, for example, preferably 0.1 to 60 minutes, more preferably 0.5 to 30 minutes. If the stirring time is less than 0.1 minute, the bubbles do not develop sufficiently. If the stirring time exceeds 60 minutes, gelation occurs during stirring due to the time change of the viscosity of the sol, and the formed pore structure is destroyed. Sometimes. Note that commercially available foaming machines (for example, used for food By using a continuous foaming machine, the specific gravity of the pore structure can be controlled, so that the specific gravity of the inorganic porous material can be easily controlled.
- the obtained porous sol is heated at a predetermined temperature, if necessary, to be gelled to form a porous gel.
- the shape and size of the pores that will eventually form the pore structure can be controlled by the viscosity of the raw material sol when the bubbles are introduced, but they are formed by introducing the bubbles before gelation.
- the pores that have been left cannot maintain their shape if left untreated, and eventually disappear. Therefore, in order to suppress the disappearance of the bubbles, a treatment (heating treatment) that further promotes gelation must be performed. preferable.
- heating is not always an essential treatment to obtain a porous gel, but it is preferable to perform heating to make it easier to control the pore structure.
- the heating temperature is preferably 5 to 30 ° C higher than the sol temperature during preparation and stirring, and more preferably 10 to 25 ° C higher than the sol temperature during preparation and stirring. .
- the porous gel After gelation (after the formation of the porous gel), the porous gel is dried to form a dry porous gel, and the obtained dried porous gel is subjected to heat treatment. In order to prevent cracks due to shrinkage, the gelled porous body is aged while keeping the temperature and humidity, and aged to form an aged gelled porous body.
- the preliminarily dried porous gel is formed by drying the preliminarily dried porous gel, drying the preliminarily dried porous gel, forming a dried porous gel, and heat-treating the dried porous gel obtained. Is preferred.
- the main drying is performed at a predetermined temperature and time described below.
- Heat treatment is preferably performed at a temperature. As the aging time is longer, the gel skeleton structure develops and becomes stronger, so that cracks and the like during subsequent drying, heat treatment, and firing can be effectively suppressed.
- a beaker containing a porous sol is sealed with a paraffin film and allowed to stand in a constant temperature bath at a predetermined temperature, for example, 40 ° C. be able to. It is preferable that the lowering rate of the humidity at the time of the pre-drying is as slow as possible because the occurrence of cracks in the inorganic porous material can be suppressed.
- the pre-dried porous gel is subjected to main drying, but the method of drying such a porous gel is not particularly limited.
- the gel porous body may be naturally dried by being left at room temperature, In addition, drying may be performed while standing in a dryer such as an oven or a furnace, and further drying may be performed in a heated air flow.
- the temperature at the time of the main drying is preferably a temperature within a range from a temperature at the time of the preliminary drying to a temperature 150 ° C. higher than the temperature at the time of the preliminary drying. The slower the rate of temperature rise during the heat treatment, the better, since the occurrence of cracks in the inorganic porous material can be reduced. Since the purpose of such a heat treatment is to decompose the organic substance (first surfactant), the heat treatment temperature is preferably 300 to 700 ° C, more preferably 400 to 600 ° C. If the temperature is lower than 300 ° C, decomposition of organic substances may be insufficient. If the temperature is higher than 700 ° C, sintering may proceed too much.
- the gel porous body may be subjected to a heat treatment as described above, and then further calcined.
- the method for firing such a porous gel material is not particularly limited, and it may be performed in a stationary state, or may be performed in an air stream such as air or oxygen.
- the firing temperature is preferably from 700 to 1400 ° C, more preferably from 800 to 1200 ° C. If the sintering temperature is less than 700 ° C, sintering may not proceed, and if it exceeds 1400 ° C, it may be melted.
- the firing time is preferably 0.5 to 10 hours, more preferably 1 to 3 hours.
- the firing time is less than 0.5 hours, sintering may not proceed, and if it exceeds 10 hours, densification may progress and the pore structure may be destroyed.
- the firing temperature is preferably set to 950 ° C. as the upper limit. If it exceeds 950, crystallization occurs, and the properties may change due to crystallization (for example, the thermal expansion behavior may be significantly changed).
- the method for producing an inorganic porous material of the present invention comprises: a metal oxide sol and a Z or metal hydroxide sol; a second surfactant; and a second pH adjuster.
- a metal oxide sol and a Z or metal hydroxide sol are mixed under the conditions of pH and temperature such that the viscosity is 100 to 20,000 mPa's to prepare a raw material sol having a predetermined gelation time.
- metal oxide and metal hydroxide At least one raw material powder selected from the group consisting of materials and metal carbonates A raw material powder preparation containing powder is prepared, and the obtained raw material sol and the raw material powder preparation are mixed, and then mechanically stirred to form a powder-containing sol porous body into which bubbles are introduced.
- the obtained powder-containing porous sol is heated at a predetermined temperature, if necessary, to be gelled to form a powder-containing porous gel, and the obtained powder-containing porous gel is dried to obtain a dry powder-containing gel. It is characterized in that a porous body is formed and the obtained porous gel containing dry powder is heat-treated.
- a metal oxide sol and / or a metal hydroxide sol preferably, a silica (S i 0 2 ) sol and / or a titania (T i ⁇ 2 ) sol are used.
- a raw material sol having a predetermined gelation time while containing at least one raw material powder selected from the group consisting of metal oxides, metal hydroxides and metal carbonates A raw powder preparation is prepared.
- the raw material slurry is preferably prepared by mixing the raw material powder with an H adjuster under the condition that the raw material powder has a concentration of 1% by weight or more and the same pH as the raw material sol. It is more preferable that the concentration of the raw material powder is 30% by weight or more.
- the obtained raw material sol and raw material powder preparation (preferably, raw material slurry) are mixed, and then mechanically stirred to form a powder-containing porous sol into which bubbles are introduced.
- the obtained powder-containing porous sol is heated at a predetermined temperature, if necessary, to be gelled to form a powder-containing porous gel,
- porous gel body containing powder is dried to form a porous gel body containing dry powder.
- the powder-containing gel porous material is dried to form a dry powder-containing gel porous material, and the resulting dry powder-containing gel porous material is heat-treated. Is aged while keeping the temperature and humidity, and aged powder A powder-containing gel porous body is formed, and the obtained aged powder-containing gel porous body is pre-dried at a reduced humidity while maintaining the temperature to form a pre-dried powder-containing gel porous body. It is preferable to dry the dry powder-containing gel porous body to form a dry powder-containing gel porous body, and to heat-treat the obtained dry powder-containing gel porous body.
- the powder-containing gel porous body is further heat-treated after heat treatment.
- silica (S i ⁇ 2 ) sol and / or titania (T i ⁇ 2 ) Sol can be mentioned.
- the raw material powder preparation (preferably, raw material slurry) used in the second production method comprises at least one type of raw material powder selected from the group consisting of metal oxides, metal hydroxides, and metal carbonates. It is preferable to include the above from the viewpoint of reactivity during firing.
- at least one kind of raw material powder selected from the group consisting of metal oxides, metal hydroxides and metal carbonates is selected from the group consisting of silicon (S i), titanium (T i), aluminum (A 1) and aluminum (A 1).
- the following items are common to those in the first manufacturing method, and thus description thereof is omitted.
- Second surfactant (same as the first surfactant)
- Second pH adjuster and third pH adjuster (same as the first pH adjuster)
- Second pH adjuster and third pH adjuster (same as the first pH adjuster)
- Firing temperature The optimum firing temperature varies depending on the combination of the type of sol and the type of raw material powder (preferably in the form of a powder slurry) (depending on the compound finally obtained). Specifically, 130 to 150 ° C for cordierite; 110 to 100 ° C for mullite; 140 ° C for forsterite; 130 for forsterite 0 to 1600 ° C; 1400 to 1600 ° C for aluminum titanate; and 700 to 1400 ° C for silica.
- Third surfactant The same surfactant as the first surfactant and the second surfactant may be used. However, in order to improve the dispersibility of powder, ammonium polyacrylate is used. It is preferable to use one to which a salt, a sodium salt of a polycarboxylic acid, an ammonium salt of a polycarboxylic acid, or the like is added. Among them, those to which ammonium polyacrylate is added are more preferable.
- Silica sol (trade name: Snowtex S, manufactured by Nissan Chemical Co., Ltd.), hydrochloric acid as a pH adjuster, and sodium lauryl sulfate ester salt as a surfactant were used.
- This raw material sol is gently stirred in a water bath maintained at 20 ° C. When the viscosity reaches 10 OmPas, mechanical stirring (mixer, 1 minute) in a 1 liter beaker at room temperature is performed.
- the beaker was sealed with a paraffin film, and allowed to stand in a constant temperature bath at 40 ° C. After allowing it to stand for 3 days, a pinhole with a diameter of about lmm was made in the film of the beaker and allowed to stand for another 3 days. Thereafter, the film was removed and left still for one day.
- the obtained dried body was heated in the air at 600 ° C for 4 hours and further at 850 ° C for 2 hours to obtain a siliceous porous body.
- Table 1 shows the type of the obtained porous body, pore size, porosity, percentage occupied by spherical pores, gas permeability coefficient, thermal conductivity, bending strength, and thermal expansion coefficient.
- Silica sol manufactured by Nissan Chemical Co., Ltd., trade name: Snowtex S
- hydrochloric acid as a pH adjuster
- sodium lauryl sulfate ester as a surfactant
- This raw material sol Stir gently in a water bath maintained at 20 ° C, and when the viscosity reaches 30 OmPas, perform mechanical stirring (mixer, 1 minute) in a 1-liter beaker at room temperature. One was sealed with a paraffin film and allowed to stand in a constant temperature bath at 40 ° C.
- a pinhole with a diameter of about lmm was made in the film of the beaker and allowed to stand for another 3 days. Thereafter, the film was removed and left for one day.
- the obtained dried body was subjected to a heat treatment at 600 ° C. for 4 hours and further at 850 ° C. for 2 hours in the air to obtain a siliceous porous body.
- Table 1 shows the type of the obtained porous material, the pore size, the porosity, the proportion occupied by the spherical pores, the gas permeability coefficient, the thermal conductivity, the bending strength, and the thermal expansion coefficient.
- Silica sol manufactured by Nissan Chemical Co., Ltd., trade name: Snowtex S
- hydrochloric acid as a pH adjuster
- sodium lauryl sulfate ester as a surfactant were used.
- the raw material sol was gently stirred in a warm bath at 20 ° C, and when the viscosity reached 50 OmPa ⁇ s, mechanical stirring was performed in a 1-liter beaker at room temperature (mixer, 1 After that, the beaker was closed with a paraffin film and allowed to stand in a 40 ° C constant temperature bath. After allowing it to stand for 3 days, a pinhole with a diameter of about lmm was made in the film of the beaker and allowed to stand for another 3 days. Thereafter, the film was removed and left for one day.
- the obtained dried body was subjected to a heat treatment in the air at 600 ° C. for 4 hours and further at 850 ° C. for 2 hours to obtain a siliceous porous body.
- Table 1 shows the type of the obtained porous material, the pore size, the porosity, the proportion occupied by the spherical pores, the gas permeability coefficient, the thermal conductivity, the bending strength, and the thermal expansion coefficient.
- Silica sol manufactured by Nissan Chemical Co., Ltd., trade name: Snowtex S
- hydrochloric acid as a pH adjuster
- sodium lauryl sulfate ester as a surfactant
- This raw material sol is gently stirred in a bath maintained at 20 ° C overnight to achieve a viscosity of 200 OmPas.
- Silica sol (trade name: Snowtex S, manufactured by Nissan Chemical Co., Ltd.), hydrochloric acid as a pH adjuster, and sodium lauryl sulfate as a surfactant were used.
- This raw material sol was gently stirred in a water bath maintained at 20 ° C. When the viscosity reached 1000 OmPa ⁇ s, mechanical stirring (mixer, 1 minute) in a 1 liter beaker at room temperature was performed.
- Titania sol manufactured by Ishihara Sangyo Co., Ltd., trade name: STS-02
- ammonia water was used as a pH adjuster
- polyoxyethylene alkyl ether was used as a surfactant.
- This raw material sol is gently stirred in a water bath maintained at 20 ° C. When the viscosity reaches 80 OmPas, mechanical stirring is performed in a 1-liter beaker at room temperature.
- Silica sol manufactured by Nissan Chemical Co., Ltd., trade name: Snowtex S
- hydrochloric acid as a pH adjuster
- sodium lauryl sulfate ester as a surfactant
- 30 g of silica powder, sodium salt of sodium lauryl sulfate and polyammonium polyacrylate as a surfactant were added to 20 g of distilled water, and hydrochloric acid was added as a pH adjuster so that the pH became 6. .
- This raw material sol and raw material slurry were each maintained at 20 ° C.
- the viscosity of the raw material sol reached 1000 OmPa ⁇ s, gently stirred in an water bath.
- room temperature .. 1 liter cylindrical shape The mold was transferred to the mold, and mechanical stirring (mixer, 1 minute) was performed therein.
- the mold was sealed with a paraffin film and allowed to stand in a 4 crc thermostat. After allowing it to stand for 2 days, it was removed from the mold and pre-dried with a humidity control drier at a temperature of 40 ° C, with the relative humidity reduced from 90% to 40% in 24 hours.
- the pre-dried body was dried at 110 ° C. for one day.
- the obtained dried body was subjected to a heat treatment in the atmosphere at 850 ° C. for 2 hours to obtain a siliceous porous body.
- Table 2 shows the type of the obtained porous body, pore size, porosity, percentage occupied by spherical pores, gas permeability coefficient, thermal conductivity, bending strength, and thermal expansion coefficient.
- Silica sol manufactured by Nissan Chemical Co., Ltd., trade name: Snowtex S
- hydrochloric acid as a pH adjuster
- sodium lauryl sulfate ester as a surfactant
- the raw material sol and the raw material slurry were each gently stirred in a water bath maintained at 20 ° C, and when the raw material sol had a viscosity of 1000 OmPas, a 1-liter cylindrical shape was formed at room temperature. Transfer to mold and mechanical stirring in it
- the mold was sealed with a paraffin film, and allowed to stand in a 40 ° C constant temperature bath. After allowing it to stand for 2 days, it was removed from the mold, and pre-dried with a humidity control drier at a temperature of 40 ° C while the relative humidity was reduced from 90% to 40% in 24 hours. The pre-dried body was dried at 110 ° C. for one day. The obtained dried body was subjected to a heat treatment at 1300 ° C. for 2 hours in the air to obtain a mullite porous body. Table 2 shows the type of the obtained porous body, pore size, porosity, percentage of spherical pores, gas permeability coefficient, thermal conductivity, bending strength, and thermal expansion coefficient.
- Silica sol (trade name: Snowtex S, manufactured by Sansan Chemical Co., Ltd.), hydrochloric acid as a pH adjuster, and sodium lauryl sulfate sodium salt as a surfactant were used.
- 26 g of alumina powder, 28 g of aluminum hydroxide powder and 57 g of talc powder, 48 g of distilled water, sodium salt of sodium lauryl sulfate and ammonium salt of polyacrylic acid surfactant were added to adjust the pH.
- the obtained dried body was subjected to a heat treatment at 1400 ° C. for 2 hours in the air to obtain a cordierite porous body.
- the type of porous body obtained pore size, porosity, proportion of spherical pores, gas permeability coefficient, thermal conductivity, bending strength, and Table 2 shows the coefficient of thermal expansion.
- Silica sol manufactured by Nissan Chemical Co., Ltd., trade name: Snowtex S
- hydrochloric acid as a pH adjuster
- sodium lauryl sulfate ester as a surfactant
- the raw material sol and the raw material slurry were each gently stirred in a bath maintained at 20 ° C, and the viscosity of the raw material sol was 10,000 mPa.
- This raw material sol and raw material slurry were each gently stirred in a water bath maintained at 20 ° C.
- a 1-liter cylindrical shape was formed at room temperature.
- Transfer to a mold perform mechanical stirring (mixer, 1 minute), and seal the mold with paraffin film. Then, it was allowed to stand in a constant temperature bath at 40 ° C. After allowing it to stand for 2 days, it was removed from the mold, and pre-dried with a humidity control drier at a temperature of 40 ° C, with the relative humidity lowered from 90% to 40% in 24 hours. This pre-dried body was dried at 110 ° C. for one day.
- the obtained dried body was subjected to a heat treatment at 1550 ° C. for 2 hours in the atmosphere to obtain an aluminum titanate porous body.
- Table 2 shows the type of the obtained porous material, pore size, porosity, percentage of spherical pores, gas permeability coefficient, thermal conductivity, bending strength, and thermal expansion coefficient.
- Silica sol manufactured by Nissan Chemical Co., Ltd., trade name: Snowtex S
- hydrochloric acid as a pH adjuster
- sodium lauryl sulfate ester as a surfactant were used.
- the prepared sol was gently stirred in a warm bath at 20 ° C, and when the viscosity reached 50 mPa ⁇ s, mechanical stirring in a 1 liter beaker at room temperature (mixer, 1 minute)
- the beaker was closed with a paraffin film and allowed to stand in a constant temperature bath at 40 ° C. After allowing it to stand for 3 days, a pinhole having a diameter of about lmm was opened in the film of the beaker and allowed to stand for another 3 days. After that, the film was removed and allowed to stand for one day.
- the obtained dried body was subjected to a heat treatment in the air at 600 ° C for 4 hours and further at 850 ° C for 2 hours to obtain a siliceous porous body.
- Table 1 shows the type of the obtained porous body, pore size, porosity, percentage occupied by spherical pores, gas permeability coefficient, thermal conductivity, bending strength, and thermal expansion coefficient.
- Silica sol (trade name: Snowtex S, manufactured by Nissan Chemical Co., Ltd.), hydrochloric acid as a pH adjuster, and sodium lauryl sulfate as a surfactant were used.
- the raw material sol was gently stirred in a bath maintained at 20 ° C overnight, and when the viscosity reached 3000 OmPa ⁇ s, mechanical stirring was performed in a 1-liter beaker at room temperature.
- the pore structure of the inorganic porous materials obtained in Examples and Comparative Examples was observed with a scanning electron microscope.
- the porous material obtained in Example 1 had a thin skeleton.
- the porous bodies obtained in Examples 2 and 3 each had a sponge structure, and were porous porous bodies in which adjacent pores were connected.
- the porous body obtained in Example 4 had a sponge structure and was a siliceous porous body in which adjacent pores were relatively unconnected.
- the porous body obtained in Example 5 had a sponge structure, and was a siliceous porous body in which each pore was independent.
- the porous body obtained in Example 6 was a titania porous body having a sponge structure in which adjacent pores were connected. As shown in FIG. 7, the porous body obtained in Example 7 had a sponge structure and each pore was an independent siliceous porous body.
- the porous body obtained in Example 8 was a mullite porous body having a sponge structure and independent pores. As shown in FIG. 8, the porous body obtained in Example 9 was a cordierite porous body having a three-dimensional network structure having a relatively thin skeleton.
- the porous body obtained in Example 10 was a forsterite porous body having a sponge structure and independent pores.
- the porous body obtained in Example 11 was an aluminum titanate porous body having a three-dimensional network structure having a relatively thin skeleton.
- the porous body obtained in Comparative Example 1 was a siliceous porous body having a three-dimensional network structure composed of a thin skeleton, but a part of the porous body had a dense structure in which bubbles disappeared. became.
- the porous body obtained in Comparative Example 2 did not well form pores, had many dense portions, and was not worthy of evaluation.
- the thermal conductivity was measured by a steady state method, and the bending strength and the coefficient of thermal expansion were measured by a method based on JIS R1'601 and R1618, respectively.
- the results are shown in Table 1. From Table 1, it can be seen that the first inorganic porous material of the present invention has a low pressure loss and a thermal expansion coefficient and mechanical strength that can be applied as a structural material when gas is permeated. Further, it can be seen that the second inorganic porous body of the present invention has a low thermal conductivity and a thermal expansion coefficient and a mechanical strength that can be applied as a structural material.
- a is the viscosity coefficient
- L is the sample thickness
- Q is the gas flow rate
- ⁇ is the pressure loss
- ⁇ is the sample area.
- Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative example 1 Comparative example 2 First inorganic First inorganic First inorganic Second inorganic Second inorganic First inorganic
- Porous body porous body
- porous body porous body
- porous body porous body
- Porous body porous body
- the inorganic porous material of the present invention and the method for producing the same are suitably used in the field of using various kinds of separation devices such as filters, and the field of using various industrial materials such as heat insulating materials.
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Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2007021037A1 (ja) * | 2005-08-19 | 2007-02-22 | Kyoto University | 無機系多孔質体及びその製造方法 |
TWI458682B (zh) * | 2008-05-16 | 2014-11-01 | Denki Kagaku Kogyo Kk | 非晶質矽石質粉末、其製造方法及用途 |
KR101506083B1 (ko) | 2012-10-22 | 2015-03-25 | 코바렌트 마테리얼 가부시키가이샤 | 단열재 |
KR101621323B1 (ko) | 2014-03-26 | 2016-05-16 | 울산과학기술원 | 티타늄 담지 메조포러스 실리케이트의 제조방법 |
JP2017109921A (ja) * | 2011-07-12 | 2017-06-22 | スリーエム イノベイティブ プロパティズ カンパニー | セラミック成形研磨粒子、ゾル−ゲル組成物、及びセラミック成形研磨粒子を作製する方法 |
CN114573366A (zh) * | 2022-03-28 | 2022-06-03 | 武汉理碳环保科技有限公司 | 一种用于碳中和的镁橄榄石多孔体及其制备方法 |
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KR101323303B1 (ko) * | 2012-02-08 | 2013-10-30 | 주식회사 화승티엔씨 | 다공성 복합화합물 및 그 제조방법, 다공성 복합화합물을 함유한 시멘트 조성물 |
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JPH04110007A (ja) * | 1990-08-31 | 1992-04-10 | Mitsubishi Materials Corp | セラミックフィルタ及びその製造方法 |
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WO2007021037A1 (ja) * | 2005-08-19 | 2007-02-22 | Kyoto University | 無機系多孔質体及びその製造方法 |
TWI458682B (zh) * | 2008-05-16 | 2014-11-01 | Denki Kagaku Kogyo Kk | 非晶質矽石質粉末、其製造方法及用途 |
JP2017109921A (ja) * | 2011-07-12 | 2017-06-22 | スリーエム イノベイティブ プロパティズ カンパニー | セラミック成形研磨粒子、ゾル−ゲル組成物、及びセラミック成形研磨粒子を作製する方法 |
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KR101506083B1 (ko) | 2012-10-22 | 2015-03-25 | 코바렌트 마테리얼 가부시키가이샤 | 단열재 |
US9139448B2 (en) | 2012-10-22 | 2015-09-22 | Covalent Materials Corporation | Heat-insulating material |
KR101621323B1 (ko) | 2014-03-26 | 2016-05-16 | 울산과학기술원 | 티타늄 담지 메조포러스 실리케이트의 제조방법 |
CN114573366A (zh) * | 2022-03-28 | 2022-06-03 | 武汉理碳环保科技有限公司 | 一种用于碳中和的镁橄榄石多孔体及其制备方法 |
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