JPH0455149B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field] The present invention relates to a method for producing an inorganic layered porous body with excellent heat insulation properties. [Background Art] As a layered compound having voids, there is an intercalation material in which a different substance such as a hydroxide is inserted and reacted between layers of a swellable inorganic layered compound (for example, Japanese Patent Laid-Open No. 54-5884 and 1977-
(See Publication No. 16386). However, since this material has a small interlayer distance of 10 Å or less, it is susceptible to the effects of adsorbed water, and it cannot be said to have very good thermal insulation properties. On the other hand, it has been proposed in Japanese Patent Publication No. 2006-11111 to use a mixture of smectite minerals and water-soluble polymer compounds as a microporous clay material, and intercalate the mixture with cationic oxides or polymeric silica. Publication No. 131878, 1983, Japanese Patent Application Publication No. 1983-
Publication No. 137812, Japanese Unexamined Patent Publication No. 137813, Japanese Unexamined Patent Publication No. 1983-137813
This is disclosed in JP-A No. 60-155526 and Japanese Patent Application Laid-Open No. 166217-1984. According to these methods, the interlayer distance can be reduced from 10 Å or less in the case of the above-mentioned intercalation material to 30 Å or less.
It can be expanded up to about 100 Å. However, such porous bodies have not achieved excellent heat insulation properties because the solid parts have a large contact and heat conduction through fixation is large. [Object of the Invention] The present invention was made in view of the above circumstances, and provides an inorganic layered porous material that has relatively large microscopic voids, has little contact between solid parts, and has excellent heat insulation properties. The purpose is to provide a method for manufacturing the body. [Disclosure of the Invention] In order to achieve the above object, the present invention involves dispersing a swellable inorganic layered compound in a solvent to swell it, inserting at least an inorganic pillar out of an inorganic pillar and an organic pillar between the layers, and then The gist of this invention is to freeze-dry a liquid to fix the swelling inorganic layered compound in a dispersed state to obtain a porous body having fine voids. Hereinafter, the present invention will be explained in detail with reference to the drawings showing one embodiment thereof. As shown in FIG. 1, which schematically shows the structure, the inorganic layered porous material A obtained by the inorganic layered porous material manufacturing method of the present invention has an inorganic compound 2 inserted and fixed between the layers 1 of the inorganic layered compound. The gap between each layer is maintained at 30 to 600 Å. Also,
The structure has relatively large voids 4 between the lumps B and B of the layers of the inorganic layered compound. Swellable inorganic layered compounds include Na-montmorillonite, Ca-montmorillonite, acid clay,
3-octahedral synthetic smectite, Na-hectolite, Li-hectolite, Na-teniolite, Li
- teniolite, synthetic mica (Na-fluorine-tetrasilicon mica), etc., but are not limited to these as long as they are swellable inorganic layered compounds. When a swellable inorganic layered compound such as Ca-montmorillonite or acid clay is used as the main material, it is difficult to swell unless a strong shearing force is applied, so it is necessary to knead it during swelling. As the inorganic pillar inserted between the layers of the swellable inorganic layered compound, at least one of a polymer obtained by hydrolyzing a metal alcoholate (hereinafter referred to as "metal alcoholate") and a colloidal inorganic compound is used. Metal Alcoholates include Si(OR) ₄ , Al
Examples include (OR) ₃ and Ge(OR) ₄ , and these may be used alone or in combination of two or more. Such a metal alcoholate becomes a polymer having a metal-oxygen bond as a main chain by the above-mentioned hydrolysis, and this becomes the above-mentioned inorganic pillar. Examples of metal alcoholates include the following compounds, but compounds other than these may also be used. _Si ( _{OC2H5 ) 4} , Si( _OCH3 ) ₄ , Ge( _OC3H7 ) ₄ , Ge( _{OC2H5 ) 4} . The colloidal inorganic compound is not particularly limited, but it is preferably a thermally stable oxide or one that expands when heated. Examples of such compounds include SiO ₂ , Sb ₂ O ₃ , Fe ₂ O ₃ ,
Examples include Al ₂ O ₃ , TiO ₂ and ZrO ₂ , and these may be used alone or in a mixture of two or more. The particle size of such a colloidal inorganic compound is also not particularly limited in this invention, but is between 50 and 150.
It is preferable that it is about Å. The above-mentioned inorganic pillars may be inserted between the layers of the swellable inorganic layered compound as they are, but the surface of the inorganic pillars may be mixed with a cationic inorganic compound and a metal alcoholate other than the metal alcoholate (hereinafter referred to as "metal alcoholate"). ) may be modified and then inserted between the layers. Cationic inorganic compounds used to modify the surface of the inorganic pillars include titanium compounds, zirconium compounds, hafnium compounds, iron compounds, copper compounds, chromium compounds,
Examples include nickel-based compounds, zinc-based compounds, aluminum-based compounds, manganese-based compounds, phosphorus-based compounds, and boron-based compounds. Examples of such cationic inorganic compounds include metal chlorides such as TiCl ₄ , metal oxysalt compounds such as ZrOCl ₂ , and nitrate compounds, but other compounds may also be used. Metal alcoholates used for the same purpose include Ti(OR) ₄ , Zr(OR) ₄ , PO(OR) ₃ and B
(OR) ₃ etc. are mentioned. These may be used alone or in combination of two or more. Examples of the above-mentioned metal alcoholates include the following compounds, but other compounds can also be used. Ti( _{OC3H7 ) 4} , Zr(OC2H7 _{) 4} , PO ₍ OCH3) ₄ , PO( _OC2H5 ) ₄ , B( _OCH3 ) ₄ , B _{( OC2H5 ) 4 .} Further, in this invention, in addition to the above inorganic pillars, at least one of a water-soluble polymer compound, a quaternary ammonium salt, an amphoteric surfactant, and a choline compound is used as an organic pillar to form the swellable inorganic layer. It can also be inserted between the layers 1, 1 of the compound. Various water-soluble polymer compounds can be considered, such as polyvinyl alcohol,
Polyethylene glycol, polyethylene oxide, methylcellulose, carboxymethylcellulose, polyacrylic acid, sodium polyacrylate,
Preferred examples include polyvinylpyrrolidone. There are various kinds of quaternary ammonium salts (cationic surfactants), but among them, those having groups such as octadecyl group, hexadecyl group, tetradecyl group and dodecyl group are preferable. As such quaternary ammonium salts,
There are the following compounds, but other compounds may be used as long as they expand the space between layers to help insert the inorganic pillars, vaporize during firing to leave voids between the layers, and can be mixed with the inorganic pillars. You can also use things. Octadecyltrimethylammonium salt, dioctadecylmethylammonium salt, hexadecyltrimethylammonium salt, dihexadecyldimethylammonium salt, tetradecyltrimethylammonium salt, ditetradecyldimethylammonium salt. Various choline compounds are possible, but
For example, [HOCH ₂ CH ₂ N(CH ₃ ) ₃ ] ⁺ OH ^- ,
C ₅ H ₁₄ ClNO, C ₅ H ₁₄ NOC ₄ H ₅ O ₆ ,
_{Preferred examples include C5H14NOC6H7O7 and C5H14NOC6H12O7 . _ _ _} In addition, various types of amphoteric surfactants can be considered, but among them, the cation part is an aliphatic amine type, and the anion part is a carboxyl group, sulfate ester group, sulfone group, or phosphate ester group. Those having at least one group selected from the group consisting of are preferred. Next, a method for producing an inorganic layered porous body according to the present invention will be explained in detail based on drawings schematically showing one embodiment thereof. Substances such as swellable clay minerals are made of a collection of swellable inorganic layered compounds _A1 , as shown in Figure 2. This compound A ₁ , which is the main material, is dispersed in a solvent such as water to create a dispersion. Then, as shown in FIG. 3, the solvent 5 is contained between the layers 1, 1, and the swellable inorganic layered compound swells. Water is generally used as a solvent, but other polar solvents such as methanol, DMF, DMSO
These may be used alone or in combination of two or more. Next, when using a polymer of metal alcoholate as the inorganic pillar 21, a solvent such as ethanol or isopropanol is added to the metal alcoholate to form a solvent, and a reaction catalyst (hydrolysis catalyst) such as water and hydrochloric acid is added to this. Add and mix to cause a hydrolysis reaction. Although this hydrolysis reaction is not particularly limited, it is preferably carried out at a temperature of about 70°C. In addition, when the hydrolysis reaction of the metal alcoholate has progressed to some extent and the nucleus has grown, the metal alcoholate or a cationic inorganic compound is added to the reaction solution, and these compounds are subjected to an addition reaction on the surface of the nucleus. As shown in Figure 4b,
A reactant 21' whose surface is positively charged is obtained. When using a colloidal inorganic compound as shown in FIG. 4a as the inorganic pillar 21,
It may be used as is, or the metal alcoholate or cationic inorganic compound may be added to the colloidal inorganic compound dispersion,
As in the previous case, these compounds are subjected to an addition reaction on the surface of the inorganic pillar 21 to obtain a reactant 21'. The reactant 21' or inorganic pillar 21 as described above is added and mixed into the dispersion liquid in which the swollen swellable inorganic layered compound is dispersed. Then, these reactants 2 are formed between the layers 1 and 1 of the layered compound.
1' or an inorganic pillar 21 is inserted (intercalation). Although the temperature during mixing is not particularly limited in the present invention, it is preferably around 60 to 70°C. In addition, when a water-soluble polymer compound, a quaternary ammonium salt, an amphoteric surfactant, or a choline compound is blended as the organic pillar 6, as shown in FIG. 5a and b, the organic pillar 6 becomes The space between the layers 1 and 1 is expanded and held, and at the same time, the movement of the inorganic pillars 21 and the reactants 21' is slowed down.
It functions to stay between layers 1 and 1. The retained inorganic pillars 21 and reactants 21' thereby hold the gap between the layers 1 and 1 while being expanded. In addition, when this inorganic pillar 21 is a reactant 21' whose surface is modified, the positive charge on its surface is electrically coupled with the negative portion on the surface of layer 1, as shown in FIG. 5b. It is thought that this makes it possible to maintain the gap between the layers 1 and 1 more widely. The above dispersion can be used as is, or
Concentrate and then dry by lyophilization. Then, the swellable inorganic layered compound and the various pillars 6, 21, 21', etc. in the dispersion are fixed in a dispersed state. After this, if necessary,
When fired at 300 to 900°C, preferably 450 to 550°C, trace amounts of organic substances contained in the inorganic pillars 21 and reactants 21', or organic pillars 6, etc. are converted into CO ₂ , NH ₃ , H ₂ O. etc. and is removed.
As shown in FIG.
is formed, and an inorganic layered porous body having relatively large voids 4 between the masses B can be obtained. The inorganic layered porous material obtained in this way has a layer spacing of 30 to 600 Å in more than 40% of the total, and the ratio of the solid part is very small, so there is very little contact with the solid part, and the insulation is Becomes excellent in sex. In the above-mentioned conventional method, the wider the interlayer distance, the more likely cracks and delamination would occur during firing. On the other hand, according to the method for producing an inorganic layered porous body of the present invention, the porous body structure after drying has large voids from which CO ₂ , NH ₃ , H ₂ O, etc. generated during firing can freely escape. Therefore, even when fired, no cracking or delamination occurs. In the above examples, the inorganic pillar or the reactant and the organic pillar were separately inserted between the layers of the swellable inorganic layered compound, but these were mixed in advance and inserted between the layers. It doesn't matter if it looks like it's being inserted. Furthermore, although the illustrated embodiment shows a case in which organic pillars are blended, as described above, in this invention, organic pillars may not be blended. In that case, an inorganic layered porous body can be obtained without performing the above-mentioned firing. Of course, even if organic pillars are not blended, there is no problem in firing. Next, examples of the present invention will be described together with comparative examples. Example 1 Silica sol (Snowtex manufactured by Nissan Chemical Industries, Ltd.), which is a colloidal inorganic compound, was used as an inorganic pillar.
A 10% by weight aqueous solution of OXS (average particle size 60 Å) was used, and in this, a cationic inorganic compound,
A 25% by weight aqueous solution of TiCl ₄ (manufactured by Hanui Chemical Co., Ltd.) was added and thoroughly mixed, and a reaction was carried out to obtain a reaction liquid in which the reactants were dispersed. At this time, silica sol and
The blending ratio of TiCl ₄ was SiO ₂ :TiO ₂ =10:1 in molar ratio in terms of SiO ₂ and TiO ₂ . This reaction solution was sufficiently mixed with octadecyltrimethylammonium chloride (Nitsusan Cation AB, manufactured by NOF Corporation), which is a quaternary ammonium salt, to obtain a mixed solution. This mixed solution was mixed with a 2% by weight aqueous solution of Na-montmorillonite (Kunipia F manufactured by Kunimine Industries Co., Ltd.), which is a swellable inorganic layered compound, which had been swollen with water in advance, and heated at 60°C.
An insertion reaction was performed for 1.5 hours to obtain a dispersion. The obtained dispersion was frozen, vacuum dried in a vacuum dryer, and then calcined at 450°C in an electric furnace.
An inorganic layered porous material sample was obtained. The weight ratio of Na-montmorillonite, SiO ₂ , TiO ₂ and quaternary ammonium salt was 1:0.6:0.08:1. Example 2 Ethanol (special grade reagent, manufactured by Hanui Chemicals, Ltd.) was added to Si(OC ₂ H ₅ ) ₄ (manufactured by Hansui Chemicals, Ltd.), which is a metal alcoholate, and thoroughly mixed to form a solution. 2N hydrochloric acid was added to this solution and heated to 70°C to perform a hydrolysis reaction to create inorganic pillar nuclei. Next, a 4M aqueous solution of TiCl ₄ (manufactured by Hanui Chemical Co., Ltd.), which is a cationic inorganic compound, is added to this reaction solution and thoroughly mixed, and a reaction is carried out to form a reaction solution in which the reactants are dispersed. I got it. Using the reaction solution thus obtained, an inorganic layered porous material sample was obtained in the same manner as in Example 1. The compounding ratio of each component is a molar ratio: Si(OC ₂ H ₅ ) ₄ : Ethanol : TiCl ₄ : 2N Hydrochloric acid =
It was 17:18:1.7:65. Example 3 Metal alcoholate instead of TiCl ₄
An inorganic layered porous material sample was obtained in the same manner as in Example 1, except that a solution obtained by hydrolyzing Ti(OC ₃ H ₇ ) ₄ with 2N hydrochloric acid was used. The mixing ratio of Ti and hydrochloric acid is 0.07:
It was 1. Example 4 An inorganic layered porous material sample was obtained in the same manner as in Example 1, except that an amphoteric surfactant (Lipomin, manufactured by Lion Corporation) was used instead of the quaternary ammonium salt. Example 5 Same as Example 1 except that synthetic mica (Daimonite HG manufactured by Topy Industries, Ltd.) was used as the swellable inorganic layered compound, and a water-decomposed one was used.
In the same manner as above, an inorganic layered porous material sample was obtained. Comparative Example 1 A molded article was obtained in the same manner as in Example 1, except that instead of performing vacuum freeze-drying, drying was performed gradually with warm air at 60°C. Comparative Example 2 Colloidal silica (average particle size 130 Å, 20% aqueous solution) was used as a colloidal inorganic compound, and Na-montmorillonite (Kunipia F manufactured by Kunimine Kogyo Co., Ltd.) was used as a swellable inorganic layered compound. Polyethylene oxide, which is a water-soluble polymer compound (Arcotox E75 manufactured by Meisei Chemical Co., Ltd.,
average molecular weight 1.5 million to 2.2 million) and 70℃ with water
and mixed for 40 minutes. This mixture was oriented into a plate shape using a spatula or the like, dried and then fired at 400° C. for 2 hours to obtain an inorganic layered porous material sample. The blending ratio of Na-montmorillonite, water, colloidal silica, and polyethylene oxide is as follows:
The weight ratio was 1:10:3:0.1. The porosity, interlayer distance, density, and thermal conductivity of the inorganic layered porous body samples obtained in these examples and comparative examples were measured, and the results are shown in Table 1 together with the comparative example of gypsum board. The porosity is determined by the following formula: Porosity = [Surface area of the sample] - [Surface area of the inorganic compound between the layers] - [Outer surface area of the layered compound in the sample] [Weight of the layered compound in the sample] x [Theoretical specific surface area when all layers of the layered compound are open] The specific surface area was obtained using the BET method in the nitrogen adsorption method, and the average interlayer distance (pore distribution) was obtained using the CI method in the nitrogen adsorption method. The nitrogen adsorption device used was Autosorb 6 manufactured by Quantachrome. Thermal conductivity was measured using a thermal conductivity measuring device based on the xenon flash method.

【table】

〔Effect of the invention〕

The method for producing an inorganic layered porous material of the present invention is constructed as described above, and the inorganic compound makes up 40% of the total
% or more, the layer spacing is maintained at 30 to 600 Å, the porosity is 40% or more, and the contact between solid parts is also very small, so it has a low thermal conductivity and is useful as a heat insulating material. This makes it possible to reliably obtain an inorganic layered porous material with excellent properties. In addition, the porous structure after drying allows CO ₂ , NH ₃ , H ₂ O, etc. generated during firing to escape freely, eliminating the risk of cracking or delamination after firing. .

[Brief explanation of the drawing]

Figure 1 is a schematic side view of an inorganic layered porous material, Figure 2 is a schematic side view of an inorganic layered porous material;
The figure is a schematic side view of a swellable inorganic layered compound.
The figure is an explanatory diagram explaining the state leading to the swelling.
Figure a is an explanatory diagram illustrating an inorganic pillar formed by hydrolyzing a colloidal inorganic compound or metal alcoholate, Figure 4 b is an explanatory diagram illustrating a reactant whose surface is modified as an inorganic pillar, and Figure 5
Figure a is an explanatory diagram illustrating the state in which the inorganic pillar and organic pillar of Figure 4 a are inserted between the layers of the swellable inorganic layered compound, and Figure 5 b is an explanatory diagram illustrating the state in which the inorganic pillar and organic pillar of Figure 4 a are inserted between the layers of the swelling inorganic layered compound, and Figure 5 b is the swelling of the reactant and organic pillar of Figure 4 b. FIG. 2 is an explanatory diagram illustrating a state in which a layered inorganic compound is inserted between layers. A... Inorganic layered porous material, A ₁ ... Swellable inorganic layered compound, B... Mass of layers of swellable inorganic layered compound, 1... Layer, 2... Inorganic compound, 3... Voids between layers, 4 ...Void between lumps, 5...Solvent, 6...
Organic pillar, 21, 21'...inorganic pillar.

Claims (1)

[Scope of Claims] 1. A swellable inorganic layered compound is dispersed in a solvent and swollen, and at least an inorganic pillar of an inorganic pillar or an organic pillar is inserted between the layers, and then this dispersion is freeze-dried to swell the swellable inorganic layered compound. 1. A method for producing an inorganic layered porous material, which is characterized by fixing an inorganic layered compound in a dispersed state to obtain a porous material having fine voids. 2. The method for producing an inorganic layered porous material according to claim 1, wherein the inorganic pillar is at least one of a colloidal inorganic compound and a hydrolyzate of a metal alcoholate. 3. The method for producing an inorganic layered porous material according to claim 1 or 2, wherein the inorganic pillar has a surface modified with at least one of a cationic inorganic compound and a metal alcoholate. 4. The organic pillar according to any one of claims 1 to 3, wherein the organic pillar is at least one of a water-soluble polymer compound, a quaternary ammonium salt, an amphoteric surfactant, and a choline compound. Manufacturing method of inorganic layered porous material. 5. The method for producing an inorganic layered porous body according to any one of claims 1 to 4, which further performs firing after drying. 6 Claim 1 in which the sky is 30 to 600 Å
A method for producing an inorganic layered porous body according to any one of Items 1 to 5.