JPH0483771A - Inorganic porous material and production thereof - Google Patents

Abstract

PURPOSE:To obtain the porous material having fine and uniform closed cell structure and excellent heat insulating properties by selecting the title porous material derived from specific plural metallic salts of acid. CONSTITUTION:The title porous material derived from a metallic salt of phosphates (e.g. ammonium primary phosphate and ammonium tertiary phosphate), a metallic salt of boric acid and/or a metallic salt of aluminates (e.g. hydrous magnesium aluminate) and an arbitrary polyvalent metal hydroxide and/or polyvalent metal carbonate (e.g. basic magnesium carbonate tetrahydrate).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inorganic porous body and a method for producing the same. More specifically, the present invention relates to an inorganic porous body that can be manufactured at room temperature and pressure, and a method for manufacturing the same.

[Conventional technology] Lightweight cellular concrete such as ALC is a typical inorganic porous material and has excellent nonflammability, but because it is manufactured through a high temperature and high pressure reaction process, special equipment and equipment are required. It has the following problems.

On the other hand, as an inorganic porous material that can be manufactured even at room temperature and normal pressure, a porous material made of metal phosphate has been proposed (for example, Japanese Patent Publication No. 36145/1983).

[Problems to be solved by the invention] However, with conventional porous bodies made of metal phosphates, it is sometimes difficult to properly adjust the timing of porosity and hardening during the manufacturing process, and it is also difficult to There have also been problems in constantly and stably manufacturing porous bodies with high levels of basic physical properties (such as compressive strength and thermal conductivity) required for applications as materials and soundproofing materials. Furthermore, when the surface of the porous body is rubbed, there are problems such as peeling of the surface layer in some cases.

[Means for Solving the Problems] The present inventors - As a result of intensive studies to solve these problems, they have arrived at the present invention.

That is, the present invention provides metal salts of phosphoric acids (a), metal salts of boric acids and/or metal salts of aluminates (b), and, if necessary, polyvalent metal hydroxides and/or polyvalent metal carbonates. Inorganic porous material derived from (c); metal salts of phosphoric acids (a), metal salts of boric acids and/or metal salts of aluminates (b), water, and if necessary polyvalent metal hydroxide and A method for producing an inorganic porous body characterized by reacting a polyvalent metal carbonate (c) and making it porous; the inorganic porous body obtained by this method is further treated with a polyvalent metal ion-containing aqueous solution (d) and This is a method for producing an inorganic porous body, characterized by immersing it in an organic solvent (e).

In the present invention, the metal salts of phosphoric acids (a) include, for example, metal phosphates such as primary metal phosphates, secondary metal phosphates, and tertiary metal phosphates; birophosphate metal salts, and tripo-IJ metal salts. Condensed phosphoric acid metal salts such as IJ acid metal salts and hexametaphosphoric acid metal salts Products in which metal salts of diphosphoric acids are partially modified with various metal oxides, hydroxides, silicates, ammonia, etc.: and these A mixture of two or more metal salts of phosphoric acids may be mentioned.

Further, the metals constituting the metal salt (a) of phosphoric acids include, for example, m metals such as lithium, sodium, potassium, magnesium, calcium, strontium, barium, aluminum, iron cobalt, nickel, zinc,
Examples include divalent or higher valent metals such as manganese, copper, chromium, cadmium, etc., and combinations of two or more of these divalent or higher valent metals.

Furthermore, as the metal salt (a) of phosphates, phosphate minerals and/or chemically modified products of phosphate minerals can also be used. The phosphate minerals include, for example, anhydrous acidic phosphate minerals (monetite, etc.); anhydrous normal phosphate minerals (triphyllite, natrophilite, etc.); hydrous acidic phosphate minerals (starcolite, etc.); Hydrous normal phosphate minerals (Stroopite, Roseite, etc.); Anhydrous phosphate minerals containing hydroxides and chlorides (Herderite, Rinkaiite, triploidite, etc.); Hydrous phosphate minerals containing hydroxides and chlorides Acid minerals (dumontite, isocrasite, polykite, turquoise, etc.): Examples include complex phosphate minerals (woodhausite, kahnite, etc.).

In addition, as chemically modified products of the above-mentioned phosphate minerals, examples of the above-mentioned phosphate minerals include lithium, sodium, potassium, magnesium, calcium, strontium, barium, aluminum, iron, cobalt, nickel, zinc, and manganese. Minerals partially modified with oxides, hydroxides, silicates, ammonia, etc. of copper, chromium, cadmium, etc.

Among these metal salts of phosphoric acids, preferred are monobasic magnesium phosphate, monobasic aluminum phosphate, monobasic zinc phosphate, and mixtures of two or more thereof, and particularly preferred are monobasic magnesium phosphate and/or monobasic zinc phosphate. Or monobasic aluminum phosphate.

Examples of metal salts of boric acid and/or metal salts of aluminates (b) in the present invention include metal borate [metal orthoborate (indium orthoborate, magnesium orthoborate, cobalt orthoborate, etc.), metal diborate, etc.] Salts include magnesium borate, calcium diborate, cobalt diborate, etc.), metal metaborate salts (potassium metaborate, sodium metaborate, calcium metaborate, etc.), metal tetraborate (sodium tetraborate, calcium tetraborate, etc.) etc.), pentaborate metal salts (potassium pentaborate, etc.); all metal salts of aluminates; hydrous aluminate metal salts (
hydrooxoaluminate metal salts (calcium hydrooxoaluminate, magnesium hydrooxoaluminate, strontium hydrooxoaluminate, double hydroxide of calcium and aluminum, double hydroxide of magnesium and aluminum) hydroxide, etc.), anhydrous alkali metal aluminate metal salts (anhydrous sodium aluminate, anhydrous potassium aluminate, etc.), spinel-type divalent metal aluminates (
anhydrous magnesium aluminate, etc.), non-spinel type aluminates (anhydrous calcium aluminate, etc.); and
Two or more combinations of these may be mentioned.

Preferred among these are metal salts of aluminates, particularly preferred are metal salts of aluminates containing magnesium and/or calcium.

Metal salts of aluminates containing magnesium are particularly effective for obtaining porous bodies with high closed cell properties, and metal salts of aluminates containing calcium are particularly effective for obtaining porous bodies with fine cell structures. There is.

In addition, metal salts of aluminates are defined as salts formed from aluminum oxide and metal oxides that are more basic than aluminum oxide, or, for convenience, among those skilled in the art,
The following general formula is used:

xMmo HyA l 20s・ZH20 (wherein, M is a metal atom, X and y are positive numbers, m is usually 1 or 2, Z
each represents a positive number greater than or equal to 0) These metal salts of aluminic acids have a ratio of X and y (x/y
), it is recognized that there are differences in their properties.

In the present invention, when using metal salts of aluminates, x/
Although y can usually be selected within a wide range, it is preferably 0.1 to 20.0, particularly preferably 0.3 to 10.0.
It is 0.

In the present invention, a porous body with higher strength can be obtained by using a polyvalent metal hydroxide and/or a polyvalent metal carbonate (c) together with (a) and (b).

Examples of (c) include polyvalent metal hydroxides such as aluminum hydroxide, synthetic aluminum hydroxide gel, magnesium hydroxide, calcium hydroxide, zinc hydroxide, barium hydroxide, and ferric hydroxide; Examples include polyvalent metal carbonates such as magnesium carbonate, calcium carbonate, strontium carbonate, iron carbonate, zinc carbonate, cobalt carbonate, basic magnesium carbonate, basic zinc carbonate, and basic cobalt carbonate.

Preferred among these are aluminum hydroxide, aluminum hydroxide genope magnesium carbonate, and basic magnesium carbonate, and particularly preferred are aluminum hydroxide gel and/or basic magnesium carbonate.

The inorganic porous body of the present invention has a metal salt of phosphoric acids (a), a metal borate, and/or a metal salt of aluminates (b) as essential components, or (a) and (b) The amount of the metal salt of phosphoric acids (a) relative to the total molar amount of is usually 10 to 99%, preferably 20 to 95%. 10%
If it is less than 9, it is difficult to harden the porous body;
If it exceeds 9%, it is difficult to obtain a porous body with a fine and uniform closed cell structure, and the strength of the porous body (IJ socks) also decreases.

Polyvalent metal hydroxide and/or polyvalent metal carbonate of the present invention
There is no particular limit to the amount of (c), but the metal salt of phosphoric acids (a) and the metal salt of borate and/or aluminic acids (b)
) is usually 0 to 300%, preferably 0 to 200%, based on the total molar amount.

In the inorganic porous body of the present invention, the general formula % formula % () i: Valency of metal atoms in the inorganic porous body El: Number of metal atoms with a valence of i in the inorganic porous body Np: The inorganic porous body The value of E, which is expressed as a constant 3 based on the number of phosphorus atoms in the body, is usually 0.1 to 100, but in order to obtain an inorganic porous body with a finer and more uniform closed cell structure, E should be It is preferable that it is 1.0 or more.

The inorganic porous body of the present invention can be produced by reacting (a), (b), water, and (c) if necessary, and making it porous using various porosity-making methods. The amount of water to be added is usually 1
It is 0-1000%, preferably 50-200%. 1
If it is less than 0%, workability decreases, and if it exceeds 1000%, curing properties and drying properties decrease.

Further, the reaction temperature and pressure may be normal temperature and normal pressure, and in order to accelerate curing and drying, curing may be performed in a dryer at room temperature to about 100°C.

On the other hand, examples of methods for creating pores include (1) a method using a foaming agent, (2) a method using a foaming agent, (2) a method using a lightweight porous body, and (2) a method using a volatile liquid.

Foaming agents used in the method (2) include, for example, carbonates (sodium carbonate, potassium carbonate, ammonium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium chloride, magnesium carbonate, calcium carbonate, strontium carbonate, barium carbonate, zinc carbonate, Iron carbonate, cobalt carbonate, basic magnesium carbonate, basic zinc carbonate, basic cobalt carbonate, etc.), light metals that generate gas by reacting with acids or alkalis (magnesium, aluminum, zinc, etc.), azide compounds (calcium azide, etc.) ), ammonium salt (
ammonium nitrite, etc.), azo compounds (azodicarbonamide, azobisisobutyronyl-IJ, etc.), nitroso compounds (dinitropentamethylenetetramine, NN
dimethyl-NN dinitrosoterephthalamide, etc.), hydrazide compounds (p-toluenesulfonyl hydracite, etc.), and the like.

Foaming agents used in method (2) include, for example, surfactants [anionic surfactants (sodium oleate, sodium tetrapropylene benzene sulfonate, sodium dioctyl sulfosuccinate), nonionic surfactants (ethylene oxide of octylphenol), (2~7
0 mol) adducts, ethylene oxide (2 to 70 mol) adducts of higher alcohols (8 to 22 carbon atoms), lauric acid jetanolamide, etc.), cationic surfactants (formate of triethanolamine monostearate) , stearamide ethyl diethylamine acetate, lauryl trimethyl ammonium chloride, stearamide methyl pyridinium chloride, cetyl pyridinium bromide, etc.), amphoteric surfactants (sodium lauryl aminopropionate, lauryl dimethyl betaine, lauryl dihydroxyethyl betaine, etc.); Animals Examples include protein-based foaming agents [trade name: Glufoam: manufactured by Sun Orient Chemical Co., Ltd.], and the like.

Existing lightweight porous materials used in method (2) include, for example,
Examples include organic foams such as polystyrene beads and polyethylene beads; foamed lightweight aggregates such as shirasu balloons, perlite, and expanded vermiculite; pulverized lightweight cellular concrete such as ALC; and pulverized inorganic porous materials of the present invention.

Examples of the volatile liquid in method (2) include Freon 11, Freon 123, Freon 141b, and methylene chloride.

Among the methods (1) to (2), preferred are methods (1) to (4) or a combination thereof.

The inorganic porous body of the present invention can be manufactured by various methods using the above-mentioned porosization method.

As a method, for example, (1) an aqueous solution of (a), (b) and if necessary, (c
), then mix the porous material (exampled in each method of ■ to ■) to make it porous. (2) Mix the aqueous solution of (a) with (b) and (c) if necessary. (3) After mixing the above porous body material into the aqueous solution of (a), (b) and (c) are mixed if necessary. (4) After adding a foaming agent to water and foaming, (a) and (b)
) and (c) if necessary.

Among these, preferred methods are (2) and (4), and particularly preferred is (2).

The inorganic porous material of the present invention can be molded using a mold of any shape (
For example, it is carried out by injecting (a), (b), and (c) if necessary into a formwork for a large panel, etc., reacting in the formwork with the method and method exemplified above, and making it porous. . Alternatively, the inorganic porous body of the present invention can be obtained by spraying, troweling, etc. onto a wall surface, etc., and reacting and making it porous, without using a mold or the like.

The inorganic porous body of the present invention can be obtained by further adding a polyvalent metal ion-containing aqueous solution ((1)) to the inorganic porous body once produced by the above method.
And/or by drying after immersing in the organic solvent (e), a porous body with less shrinkage during drying and higher strength can be obtained. Alternatively, (d) and/or (e) may be applied to the surface of the inorganic porous material and then dried.

As the polyvalent metal ion-containing aqueous solution (d), for example,
Examples include metal ions such as magnesium, calcium, strontium, barium, aluminum, iron, cobalt, nickel, zinc, manganese, copper, chromium, and cadmium, or aqueous solutions of salts containing two or more of these metal ions.

Examples of the organic solvent (e) include organic solvents with relatively high polarity [lower alcohols (methanol, ethanol,
n7” lovanol, iso-furopanol, etc.), low-molecular glycols (ethylene glycol, etc.), low-molecular triols (glycerin, etc.), low-molecular ketones (acetone, etc.), low-molecular esters (methyl ethyl ketone, etc.) 5. Low-molecular ethers (dioxane, diethyl ether, etc.), low-molecular amines (triethanolamine n-butylamine, etc.), dimethylformamide, dimethyl sulfoxide, etc.; and organics with relatively low polarity. Examples include solvents [low-molecular paraffins (hexane, heptane, octane, etc.)], aromatic solvents (solvents (toluene, xylene, pyridine, phenetol, etc.)).

Among (d) and/or (e), (d) is preferred, and particularly preferred is an aqueous solution containing metal ions of magnesium, calcium, and/or aluminum.

Further, when an aqueous solution containing polyvalent metal ions is used, the concentration of the aqueous solution is not particularly limited or is usually 0.1 to 70% on a weight basis.

In order to improve the water resistance of the inorganic porous material of the present invention, a water repellent can also be added during the manufacturing process.

Examples of water repellents include alkylphosphonium salts (tetrabutylphosphonium hydroxide, etc.), halaffin wax, silicone oil, mineral oil, higher alcohols (lauryl 7/l/coal, etc.), higher fatty acid esters (stearyl, etc.). acetate, etc.), metal salts of higher fatty acids (aluminum stearate, etc.), organic amines, monoalkylamines (monobutylamine, monooctylamine, etc.) and their salts, dialkylamines (diakylamine,
dilaurylamine, hexyloctylamine, etc.) and their salts, trialkylamines (tributylamine, trialkylamine, etc.) and their salts, cyclic amines (aniline, etc.) and their salts]; Alkyl phosphoric acids [monoalkyl phosphoric acids (mono octyl phosphoric acid, monohexyl phosphoric acid, monostearyl phosphoric acid, etc.) and their salts, dialkyl phosphoric acid (dibutyl phosphoric acid, butyl octyl phosphoric acid, etc.) and their salts]: and phosphoric acid alkyl esters [phosphoric acid monoalkyl esters] (monobutyl phosphate, monostearyl phosphate, etc.) and their salts, dialkyl phosphate (dihexyl phosphate, butyloctyl phosphate, distearyl phosphate, etc.) and their salts, monoalkyl phosphite (monooleyl phosphite, monostearyl phosphite, etc.) and their salts, dialkyl phosphite (stearyldodecyl phosphite, dinonyl phosphite, etc.)].

Among the water repellent agents listed above, examples of the salts forming the water repellent include organic amine salts, salts with inorganic acids such as hydrochloric acid, salts with organic acids such as acetic acid, and metal salts of organic amines. In the case of alkyl phosphates and phosphoric acid alkyl ester salts, chelates, etc. with lithium, sodium, potassium,
Magnesium, aluminum, calcium, iron, zinc,
Examples include salts with metals such as copper, nickel, and cobalt.

When using the water repellent in the inorganic porous body of the present invention, the amount used is as follows: (a), (b) and if necessary
It is usually 0.01 to 10%, preferably 0.05 to 8% based on the total weight of (c).

Furthermore, the water resistance of the inorganic porous body of the present invention can be improved by coating or impregnating the surface of the porous body with a silane cutting agent, aluminum alcoholate, aluminum chelate compound, titanium alcoholate, titanium chelate compound, etc. .

Furthermore, it is also possible to use the following reinforcing additives for the purpose of improving the strength of the inorganic porous matrix.

Examples of additives include plate-like silicate minerals such as bentonite, plate-like phosphates such as zirconium phosphate, fibrous silicates such as acpargite, asbestos, rock wool, glass wool, carboxymethylcellulose sodium salt, etc. Cellulose compounds, calcium silicates such as wollastonite, silica sand, gypsum, etc. can be used.

The amount of additive used varies depending on the type, or metal salts of phosphoric acids (a), borates and/or aluminates (b)
and, if necessary, approximately 0.1 to 1000 based on the total weight of the polyvalent metal hydroxide and/or polyvalent metal carbonate (c).
% range.

The specific gravity of the inorganic porous body obtained by the method of the present invention can be adjusted over a wide range. It also has a relatively high compressive strength considering its specific gravity. Particularly, those having a specific gravity of 0.2 or less and a compressive strength of 0.3 kg/cm2 are useful for reducing the weight of large panels and soundproofing materials.

On the other hand, because it has fine and uniform closed cells, it has a thermal conductivity of 0.05kcal/+nhr'C (average temperature 30℃).
) The following materials can also be produced and are particularly useful as heat insulating materials.

Further, the surface layer of the inorganic porous body of the present invention does not peel off due to friction or the like.

Therefore, the inorganic porous body manufactured based on the present invention is
■Insulating materials, soundproofing materials, fireproofing materials for large exterior and interior wall panels, ■Sprayed type fireproof covering materials, ■Lightweight aggregates, ■Insulation materials for fireproof safes, ■Void filling materials, ■Repairs of ALC, etc. It is useful as wood, etc.

[Example] The present invention will be explained below with reference to Examples, but the present invention is not limited thereto. In Examples and Comparative Examples, parts are parts by weight, compressive strength was measured in accordance with JIS K-7208, and thermal conductivity (measured at an average temperature of 30°C) was measured in accordance with JIS A-1413.

Further, the formulations used in Examples and Comparative Examples are as follows.

a-5; Monosodium phosphate a-6: Monobasic zinc phosphate trihydrate, gold borate, and metal salt of aluminate bb-1; Hydrous magnesium aluminate (MgD/A12Da”3.0) b-2 ; Hydrous calcium aluminate (caO/A1□0s=3.0) b-3; Anhydrous calcium aluminate (ca[]/A1zOa4.0) b-4; Anhydrous calcium aluminate (can/A12[]s=2 .0) b-5; Magnesium diborate b-6; Calcium tetraborate hexahydrate phosphoric acid a al; Primary aluminum phosphate a-2; Aluminum diphosphate a-3: Tertiary phosphoric acid Aluminum a-4; Magnesium monophosphate dihydrate value Gold m2 m3 and salt C; Synthetic aluminum hydroxide gel; Magnesium hydroxide; Basic magnesium carbonate tetrahydrate, Zz 1; Potassium carbonate ( Foaming agent) Z-2; Monooctylamine (water repellent) Z-3; Foamed vermiculite (lightweight porous material) Z-4: Animal protein foaming agent Product name: Glufoam Table 1 Examples 1 to 3 and comparison Examples I to 4 After preparing an aqueous solution or aqueous slurry of metal phosphate based on the composition shown in Table 1, the remaining formulation was added. After stirring uniformly with a homomixer, a mold (50X 30X
3 cm) and foamed to obtain a porous molded product.

Next, the molded products of Examples 1 and 2 and Comparative Examples 1 and 2 were cured for 7 days at a temperature of 20° C. and a humidity of 40%, and then subjected to a test.

The molded product of Example 3 was immersed in 20 liters of a 50% aqueous solution of magnesium sulfate and superhydrate for 1 hour, then cured under the same conditions as the others and subjected to testing.

The porous bodies of the present invention and the manufacturing method thereof shown in Examples 1 to 3 in Table 1 have uniform closed cells, and the average cell diameter is 0.5 to 2. Omm
An inorganic porous material was obtained stably and with good reproducibility. Also,
The surface condition was good, and the surface layer did not peel off even when rubbed by hand. On the other hand, the metal phosphate porous bodies of Comparative Examples 1 to 3 had many bubbles or non-uniform, interconnected areas, and peeling of the surface layer was observed when rubbed by hand. Further, in the formulation of Comparative Example 4, no porous body was formed.

Table 2 shows the physical property measurement results of each porous body. The porous bodies of the present invention in Examples had higher compressive strength and lower thermal conductivity than the foamed bodies in Comparative Examples.

Table 2 Examples 4-5 The formulations shown in Table 3 were used in Examples 4.5, respectively.

The procedure for producing the foam is as follows.

In the case of Example 4, after adding blend z-4 to water, a preform was created using a whisk, and then the remaining blend was added in its entirety and mixed with a mortar mixer.
The mixture was poured into a mold (50×30×3 an) and cured to obtain an inorganic porous body of the present invention.

In the case of Example 5, after adding z-3 to water, it was made into a thin slice slurry using a homomixer at high speed (10,000 rpm). Next, compound z-4 was added to this slurry to produce a preform in the same manner as in Example 4, and the remaining compound was added and cured in a mold to obtain the inorganic porous body of the present invention. .

After drying both Examples 4 and 5 in a dryer (50°C) for 6 hours,
It was demolded and used for testing.

Table 3 Table 4 In both Examples 4 and 5, foams with an average cell diameter of about 1.0 mm and highly closed cell properties were obtained.

Table 4 shows the physical properties of these porous bodies.

Example 6 The formulations shown in Table 5 were used in Example 6.

First, the entire amount of the metal phosphate was dissolved in water to prepare a metal phosphate aqueous solution. After adding the remaining ingredients to this aqueous solution and stirring uniformly with a homomixer, formwork (IOX IOX 1
5 cm) and was foamed and cured to obtain a molded inorganic porous material of the present invention.

This molded product was dried at a temperature of 25° C. for 10 days, and after demolding, it was subjected to a test.

Table 6 Table 5 The prepared porous body of the present invention has an average cell diameter of 1. It was Omm. Other physical properties are shown in Table 6.

[Effects of the Invention] The inorganic porous body and the manufacturing method thereof of the present invention have the following effects.

(1) By skillfully adjusting the timing of porous formation and curing, porous bodies with fine and uniform closed cell structures and excellent heat insulation properties can be stably produced at all times.

In particular, when the value of E is 1.0 or more, a porous body having an average cell diameter of 2 or less and having higher closed cell properties (lower thermal conductivity) can be obtained.

That is, the timing adjustment of porosity and curing, which were problems in the past, could be improved.

(2) Compared to conventional porous bodies, even those with relatively low specific gravity have higher strength, so large panels and the like can be made lightweight.

(3) Since it can be produced under normal temperature and normal pressure production conditions, special reaction equipment such as autoclave curing is not required.

(4) It can be easily made porous and hardened in a mold of a desired shape.

It is also possible to trowel, spray, etc. on the wall surface and harden it.

(5) The surface condition is good and the surface layer does not peel off even when rubbed by hand.

The conventional problem of peeling of the surface layer when rubbed by hand is eliminated.

Because of the above-mentioned effects, the inorganic porous bodies of the present invention and the method for producing the same can be used as: ■ insulation materials, soundproofing materials, fireproofing materials for external wall panels and internal wall panels, ■ fireproof coating materials, ■ lightweight aggregates, ■ It is suitable for use as a heat insulating material for fireproof safes, (1) void filling material, (2) repair material for ALC, etc.

Claims (1)

[Scope of Claims] 1. Metal salts of phosphoric acids (a), metal salts of boric acids and/or metal salts of aluminic acids (b), and, if necessary, polyvalent metal hydroxides and/or polyvalent metals. An inorganic porous material derived from carbonate (c). 2. General formula E=[Σ(i×Ei)]/(kNp) i: Valency of metal atoms in the inorganic porous body Ei: Number of metal atoms with valence i in the inorganic porous body Np: 2. The inorganic porous body according to claim 1, wherein the value of E, expressed as the number k of phosphorus atoms in the inorganic porous body: constant 3, is 1.0 or more. 3. Specific gravity 0.2 or less,
Claims 1 to 3 have a compressive strength of 0.3 kg/cm^2 or more and a thermal conductivity of 0.05 kcal/mhr°C or less.
2. The inorganic porous body according to any one of 2. 4. Metal salts of phosphoric acids (a), metal salts of boric acids and/or metal salts of aluminates (b), water, and if necessary polyvalent metal hydroxides and/or polyvalent metal carbonates (c ) and making it porous. 5. A method for producing an inorganic porous body, which further comprises immersing the inorganic porous body according to claim 4 in an aqueous solution containing polyvalent metal ions (d) and/or an organic solvent (e).