JPH11217280A - Inorganic acoustic material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an inorganic acoustic material having excellent freezing and melting resistance (or freezing fracture resistance) besides a porous body and excellent acoustic properties. SOLUTION: This inorganic acoustic material is obtained by coating 0.03-0.1 g/m<2> organic silicon compound of the formula [R1 is a 1-16C alkyl; R2 is a 1-5C alkyl; (n) is a natural number of 1-20] on an inorganic porous body produced from an amorphous SiO2 -Al2 O3 -based powder, an alkali metal silicate and water, and having 0.05-0.3 mm open cell diameter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inorganic sound absorbing material which is suitably used as a non-combustible building material and has excellent freeze-thaw resistance.

[0002]

2. Description of the Related Art Conventionally, many inorganic sound absorbing materials have been proposed. For example, JP-A-4─292482, SiO ₂ -Al ₂ O ₃ system powder, an alkali metal silicate solution, the filler, the addition of the liquid silicone oil in a predetermined ratio to the mixture of the blowing agent It is described that an inorganic porous material having hydrophobicity and excellent sound absorption can be obtained.

However, the conventional inorganic porous material as described above has a large continuous pore diameter, insufficient water repellency, and a large water absorption. Therefore, when it is used outdoors during the winter freezing period, it absorbs water. However, there is a problem that the so-called "freezing fracture" occurs in which the inorganic porous material itself collapses due to repeated expansion and contraction.

[0004] In order to prevent this, it is necessary to impart a high level of water absorption prevention to the porous body, and a large amount of water repellent must be applied. As a result, there is a defect that the continuous pores are closed by the water repellent, so that not only the sound absorbing property is reduced, but also the cost is increased.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has excellent freeze-thaw resistance (or high freeze-thaw resistance while being porous and having high sound absorption properties). It is an object of the present invention to provide an inorganic sound absorbing material having freezing destructibility.

[0006]

The inorganic sound absorbing material according to the first aspect of the present invention (hereinafter referred to as the first invention) is an amorphous SiO ₂ -Al ₂ O ₃ powder, an alkali metal silicate. ,
And made from water, continuous pore size 0.05-0.3
mm, and an organic silicon compound represented by the following general formula [1] is applied to the inorganic porous material having a thickness of 0.03 to 0.1 g / cm ² . (R ₁ is an alkyl group having 1 to 16 carbon atoms, and R ₂ is an alkyl group having 1 carbon atom.
To 5 alkyl groups, n is a natural number of 1 to 20)

The invention described in claim 2 of the present application (hereinafter referred to as “second
The inorganic sound absorbing material according to the first aspect of the present invention is obtained by applying the organic silicon compound represented by the general formula [1] in an amount of 0.01 to 0.1 g / cm ² after the inorganic porous material is dealkalized. It is characterized by being.

The first invention and the second invention relate to an inorganic sound absorbing material, and have a close relationship with each other.
Hereinafter, these will be collectively referred to as the inorganic sound absorbing material of the present invention and described.

The amorphous SiO ₂ —Al ₂ O ₃ based powder is S
iO ₂ is 10 to 90 wt%, Al ₂ O ₃ is used as a composition of 90 to 10 wt%, if specifically illustrated, the dust in the production of alumina abrasives, fly ash, fly ash Classified and crushed products, metakaolin,
Powder obtained by melting fly ash and spraying into gas, powder obtained by melting clay made of silica-alumina-based powder and spraying into gas, and applying mechanical energy to silica-alumina-based powder Powder obtained by subjecting clay minerals to heat and dehydration at 500 to 900 ° C. can be used as powder obtained by applying mechanical energy to the powder. However, the present invention is not limited to this.

The alkali metal silicate has a general formula of M ₂ O.
n SiO ₂ (M = Li, K, Na or a mixture thereof), wherein the number n is preferably n = 0.05
-8, more preferably n = 0.1-3, and most preferably n = 0.5-2.5. When n exceeds 8,
The aqueous alkali metal silicate solution is liable to gel and the viscosity rises rapidly, making it difficult to mix with the powder. or,
When n is less than 0.05, the mechanical strength of the inorganic porous body decreases. The alkali metal silicate is preferably added and mixed in the form of an aqueous solution from the viewpoint of reaction control.

The concentration of the aqueous alkali metal silicate solution is not particularly limited, but is preferably 10 to 60% by weight. If the concentration of the alkali metal silicate aqueous solution exceeds 60% by weight, a viscosity suitable for producing an inorganic porous material cannot be obtained. Also, 10
When the amount is less than% by weight, water is excessive, so that shrinkage is large at the time of curing, and a predetermined mechanical strength cannot be obtained.

The addition amount of the alkali metal silicate is as follows.
0.2 parts per 100 parts by weight of iO ₂ —Al ₂ O ₃ based powder
To 450 parts by weight, more preferably 10 to 3 parts by weight.
50 parts by weight, most preferably 20 to 250 parts by weight. If the amount of the alkali metal silicate is less than 0.2 parts by weight, the curing will be poor because the amount of alkali required for the reaction is too small. Conversely, if it exceeds 450 parts by weight,
Since the amount of the curing agent is large, the water resistance of the inorganic porous body is deteriorated.

The amount of water to be added to the amorphous SiO ₂ —Al ₂ O ₃ powder and the alkali metal silicate is as follows.
35 to 1 with respect to 100 parts by weight of the _2- Al ₂ O ₃ powder.
500 parts by weight is preferred, and more preferably 45 to 10 parts by weight.
00 parts by weight, most preferably 50 to 500 parts by weight. If the amount of water exceeds 1500 parts by weight, the viscosity at the time of producing the inorganic porous material decreases, the foaming stability deteriorates, and the strength of the obtained porous material also decreases. Also, 35
If the amount is less than 10 parts by weight, the viscosity is too high, which is not suitable for foaming.

In the present invention, if necessary, an inorganic filler, a reinforcing fiber, a foaming aid, and an inorganic foaming material may be appropriately added. Hereinafter, the above additives will be described one by one.

The inorganic filler contributes to reduction of shrinkage during curing, improvement of slurry fluidity, densification of cells, stabilization of air bubbles, etc., for example, silica sand, silica powder, fly ash, slag, silica fume, Examples include mica, talc, wollastonite, calcium carbonate, aerosil, silica gel, zeolite, activated carbon, and porous bodies of alumina gel.

The average particle size of the inorganic filler is from 0.01 μm to
A range of 1 mm is preferable, and if it exceeds 1 mm, a stable inorganic porous body cannot be obtained.
The amount of adsorbed water increases, the viscosity of the raw material of the inorganic porous body increases, the workability deteriorates, and the foaming property decreases.

The amount of the inorganic filler, an amorphous SiO ₂ -
The amount is preferably 20 to 600 parts by weight, more preferably 40 to 400 parts by weight, based on 100 parts by weight of the Al ₂ O ₃ powder. If the amount is less than 20 parts by weight, it is meaningless to add a filler, and if it exceeds 600 parts by weight, the strength of the inorganic porous material is reduced.

The reinforcing fibers improve the strength of the inorganic porous material and help prevent cracks. For example, vinylon, polypropylene, aramid, acrylic, rayon, carbon,
Examples include glass, potassium titanate, alumina, steel, slag wool, and the like.

The length of the reinforcing fibers is preferably in the range of 1 to 15 mm. If the length is too long, the dispersibility of the reinforcing fibers in the raw material of the inorganic porous material is deteriorated. If the length is too short, the desired strength of the inorganic porous material is obtained. Can not be obtained.

The diameter of the reinforcing fibers is preferably from 1 to 500 μm. If the diameter is too small, the fibers are re-agglomerated when mixed with the inorganic porous material, fiber balls are formed, and the strength of the porous material is not improved. When the thickness is large, the effect of reinforcement is small.

The addition amount of the reinforcing fiber is amorphous SiO ₂ -A
It is 10 parts by weight or less based on 100 parts by weight of l ₂ O ₃ -based powder. If the addition amount exceeds 10% by weight, the dispersibility in the inorganic porous material decreases.

The foaming aid contributes to stabilization of foaming, uniformity and fineness, and includes porous powders and surfactants. As the former, for example, silica gel, zeolite, activated carbon, alumina gel and the like can be mentioned. The addition amount is preferably 5 parts by weight or less, and if it is large, bubbles are broken, which adversely affects the production of a porous body. The latter include fatty acid metal salts such as metal stearate, metal oleate and metal palmitate, such as zinc stearate, calcium stearate, aluminum stearate, sodium oleate, potassium oleate, and palmitate. Sodium, potassium palmitate, sodium laurylbenzenesulfonate, sodium lauryl sulfate and the like.

The amount of the foaming aid to be added is amorphous SiO ₂ -A
to l ₂ O ₃ system powder 100 parts by weight, 0.05 to 5 parts by weight is preferred, more preferably from 0.3 to 3.0 parts by weight. When the addition amount exceeds 5 parts by weight, the viscosity of the porous material increases, adversely affecting the production, and conversely, 0.0%.
If the amount is less than 5 parts by weight, the bubbles are broken and the production is not stable.

The inorganic foam material is useful for reducing the weight of the inorganic porous material. Examples thereof include a glass balloon, a shirasu balloon, a fly ash balloon, a silica balloon, a pearlite,
Hill stone, granular expanded silica and the like can be mentioned, and at least one of these can be used. These specific gravities are from 0.01 to
1 is preferable, and 0.03-0.7 is more preferable. When the specific gravity is less than 0.01, the mechanical strength of the inorganic porous material is reduced, and when it exceeds 1, it does not contribute to weight reduction. The amount of the inorganic foam added was amorphous SiO ₂ —Al ₂
Against O ₃ system powder 100 parts by weight, preferably 10 to 100 parts by weight, more preferably 30 to 80 parts by weight. If the amount is less than 10 parts by weight, the effect of weight reduction cannot be obtained, and if it exceeds 100 parts by weight, the mechanical strength decreases.

There are various methods for producing the above-mentioned inorganic porous material, including a foaming agent method, a foaming agent method, and an elution / firing method. Hereinafter, these will be sequentially described.

In the foaming agent method, a foaming agent such as a peroxide or a metal powder is uniformly mixed with an inorganic porous material, and this is decomposed and decomposed.
This is a method of gasifying and forming and hardening bubbles inside. Examples of the peroxide include hydrogen peroxide, sodium peroxide, potassium peroxide, sodium borate and the like, and oxygen is generated in the presence of an alkali.

The concentration of the aqueous peroxide solution is preferably from 0.5 to 35% by weight, more preferably from 1 to 25% by weight. If the amount is less than 0.5% by weight, the viscosity is too low, and the cells are broken to make it impossible to manufacture. If the amount exceeds 35% by weight, the foaming speed is too fast, and the foaming becomes unstable. The amount of the peroxide is preferably 0.01 to 10 parts by weight based on 100 parts by weight of the amorphous SiO ₂ —Al ₂ O ₃ powder. 0.0
If the amount is less than 1 part by weight, the expansion ratio becomes too small.
If the amount exceeds 0 parts by weight, the foaming gas becomes excessive, and the bubbles burst.

As the above metal powder, for example, Mg,
Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, A
l, Ga, Sn, Si, ferrosilicon, etc., and reacts with an alkali to generate hydrogen, thereby foaming the inorganic porous material. The average particle size of the metal powder is 1 to 20
0 μm is preferable, and when it is less than 1 μm, the reaction is too vigorous and the generation of foaming gas is too early, and when it exceeds 200 μm, the reaction is too slow and the stability of foaming is poor in any case.

The amount of the metal powder to be added is amorphous SiO ₂ -A
against l ₂ O ₃ system powder 100 parts by weight, 0.01 to 5.
0 parts by weight is preferred. If the amount is less than 0.01 parts by weight, the density of the inorganic porous body is too large, and no sound absorbing property is exhibited,
If it exceeds 5.0 parts by weight, the amount of the foaming gas is excessive, and the production of the inorganic porous material is not stable.

The foaming agent method is also called a mechanical floss method, in which a foaming agent is added to a porous material and stirred with a predetermined foaming device to form a stable foamed fluid, which is cured. This is a method of forming a porous body. Examples of the foaming agent include animal protein surfactants such as casein, glue and albumin, anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. The addition amount of the foaming agent is preferably 0.05 to 5 parts by weight based on 100 parts by weight of the amorphous SiO ₂ —Al ₂ O ₃ -based powder, and when less than 0.05 part by weight, the foaming is performed. When the content and the foaming property are insufficient and the content exceeds 5 parts by weight, the foaming power is too strong, the density of the porous body is reduced, and the mechanical strength is reduced.

The elution / firing method is to uniformly mix and cure the organic foam powder or granular material with the inorganic porous material, and then heat the organic foam to a temperature higher than the melting temperature and firing temperature. Alternatively, it is a method of dissolving and eluting with an organic solvent to produce a continuous pore structure. Examples of the organic foam include foams such as styrene, ethylene, polypropylene, urethane, phenol, and urea, and the foam structure of the foam is independent, regardless of open cells, and two or more kinds may be used in combination. . The amount of the organic foam added is amorphous SiO ₂ -Al
_{The amount} is preferably from 10 to 100 parts by weight, more preferably from 30 to 80 parts by weight, based on 100 parts by weight of the ₂ O ₃ powder. When the amount is less than 10 parts by weight, no sound absorbing property is exhibited, and
If the amount exceeds 0 parts by weight, the mechanical strength of the inorganic porous material decreases.

In the present invention, in order to produce an inorganic porous material, a mixture of an amorphous SiO ₂ —Al ₂ O ₃ powder, an alkali metal silicate and water is mixed with a foaming agent as a porous means.
One of a foaming agent and an organic foam is added, and in some cases, at least one of an inorganic filler, a reinforcing fiber, a foaming aid, and an inorganic foaming material is added, and the mixture is mixed by a mixer to form a uniform slurry. To be. Thereafter, the slurry is poured into a predetermined container (mold) and cured. Although curing may be performed at room temperature, the curing is accelerated at 50 to 100 ° C., and the mechanical strength is improved. The curing time is preferably 2 to 24 hours.

The inorganic porous material used for the inorganic sound absorbing material of the present invention is obtained as described above, and it is necessary that the continuous pore diameter is 0.05 to 0.3 mm. When the continuous pore diameter is less than 0.05 mm, when the organosilicon compound represented by the general formula [1] is applied, the continuous pores are closed, and the sound absorbing property is significantly reduced. In addition, the continuous pore diameter is 0.
When it exceeds 3 mm, water easily penetrates into the inside, and water resistance and freeze-thaw resistance (or freeze-break resistance) decrease.
In addition, the said continuous pore diameter means the diameter of the pore of the part where the closed cells are adjacent to each other and the adjacent cell membrane (cell) is broken, and the measuring method is described in the evaluation method described later. I have.

The inorganic porous material thus obtained is directly or subjected to a dealkalization treatment, and is coated with the organosilicon compound represented by the general formula [1] to obtain the inorganic sound absorbing material of the present invention.

There are various methods for dealkalizing the inorganic porous material, such as a water immersion method, an acid aqueous solution immersion method, and an acid gas contact method. In the water immersion method, the inorganic porous body is washed and immersed in warm water of 80 to 90 ° C. for a long time,
This is repeated several times, and then dried at room temperature or in a heating oven. In the acid aqueous solution immersion method, an aqueous solution of pH 3 to 6 acidified with hydrochloric acid, sulfuric acid, nitric acid, carbonic acid or the like is prepared, and the inorganic porous material is added to a large volume aqueous acid solution at a weight ratio of 1: 5 or more. After being immersed for 2 hours or more to neutralize the alkali content, it is sufficiently washed with water and dried at room temperature or in a heating oven. The acidic gas contact method is a method in which an inorganic porous material is left in an atmosphere of an acidic gas such as hydrogen sulfide, hydrogen chloride, or carbon dioxide for 24 hours or more. Dry in a heating oven.

The organosilicon compound represented by the general formula [1] is as follows.

Here, R ₁ must be an alkyl group having ₁ to 16 carbon atoms, and is preferably 4 or more from the viewpoint of improving hydrophobicity. When the amount of carbon exceeds 16, the solubility in the organic solvent is deteriorated, and it may be difficult to uniformly coat the inorganic porous material. R ₂ is an alkyl group having 1 to 5 carbon atoms. When the number of carbon atoms exceeds 5, the reactivity at the time of curing decreases. Further, n needs to be a natural number of 1 to 20, and is preferably 3 to 10. When n exceeds 20, the viscosity increases, the permeability of the inorganic porous body into the deep part decreases, and the continuous pores are closed, so that the sound absorbing property decreases.

The organosilicon compound represented by the general formula [1] to be used is usually applied to an inorganic porous material so that it is usually used.
It is preferable to dilute with an organic solvent. The organic solvent is not particularly limited as long as the organic silicon compound can be uniformly dissolved, and examples thereof include ethyl alcohol and n-
Alcohols such as propanol, i-propanol and t-butanol; ethers such as ethylene glycol monomethyl ether, ethylene glycol monoester ether and ethylene glycol diethyl ether; ketones such as acetone and methyl ethyl ketone; alkanes such as fatty acid naphtha and mineral spirits Kind, toluene,
Examples include hydrocarbons such as xylene, sorbennaphtha and aromatic naphtha, and halogenated hydrocarbons such as trichloroethylene and perchloroethylene, and at least one of these can be used.

The concentration of the solution of the organic silicon compound in the organic solvent is preferably 5 to 20% by weight, and when the concentration is within this range, the inorganic porous material can be suitably applied. In the above solution,
A catalyst such as dibutyltin laurate may be added for the purpose of accelerating the condensation reaction, or a pigment or a filler may be appropriately added for the purpose of coloring or increasing the amount of the material depending on the purpose.

The amount of the organosilicon compound represented by the general formula [1] is different depending on whether the inorganic porous material is treated with alkali or not. When the inorganic porous material is untreated, the solid content of the organosilicon compound is 0.
03-0.1 g / cm ² is required, and 0.03 g / c
If it is less than m ² , the water resistance and freeze-thaw resistance will be insufficient, and if it exceeds 0.1 g / cm ² , the continuous pores of the inorganic porous material will be blocked and no sound absorption will be obtained.

In the case where the inorganic porous material has been treated with an alkali, the content of the organic silicon compound is preferably from 0.01 to 0.01 in terms of solids.
0.1 g / cm ² is necessary, and if it is less than 0.01 g / cm ² , the water resistance, freeze-thaw resistance becomes insufficient,
If it exceeds 0.1 g / cm ² , the continuous pores of the inorganic porous material are blocked, and no sound absorbing property can be obtained.

The method for coating the inorganic porous material is not particularly limited, and known means such as air spray, roll, brush, and dipping can be applied. After application to the inorganic porous material, it is preferable to leave at room temperature for 24 hours or more and further heat at 50 to 110 ° C. in order to fix the organic silicon compound.

[0043]

In the inorganic sound absorbing material of the present invention, a predetermined amount of a specific organic silicon compound is applied to an inorganic porous material having a specified composition and a continuous pore diameter. In the presence of water, the organosilicon compound spontaneously hydrolyzes into alkyl silanols and alcohols, and the alkyl silanols react with silicon on the surface of the inorganic porous body, hydroxyl groups of aluminum, and condense themselves, A siloxane bond forms and cures. Therefore, the inorganic sound absorbing material of the present invention has a high sound absorbing property in a porous body, and the organic silicon compound is applied and cured at a particularly high concentration on the surface and in the vicinity thereof. Highly imparted, water does not penetrate inside, and is excellent in water resistance and freeze-thaw resistance.

[0044]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail with reference to examples and comparative examples. As Examples 1-4 and Comparative Examples 1-7 (1) amorphous SiO ₂ -Al ₂ O ₃ -based powder of preparing amorphous SiO ₂ -Al ₂ O ₃ -based powder, two kinds of inorganic below Powders 1 and 2 were prepared. Inorganic powder 1: dust when producing an alumina-based abrasive. The composition and average particle size are as shown in Table 1.

[0045]

[Table 1]

Inorganic powder 2: Fly ash (manufactured by Kanden Kako Co., Ltd., average particle diameter 20 μm measured according to JIS A 6201) was classified by a classifier (manufactured by Nisshin Engineering Co., Ltd., model: TC-15). Average particle size is 10μ
m or less.

(2) Preparation of Inorganic Porous Material Based on the composition shown in Table 2, amorphous SiO ₂ —Al ₂
O ₃ powder (inorganic powders 1 and 2), sodium silicate aqueous solution, talc (manufactured by Sanyo Clay Industry Co., Ltd., talc 83, average particle size: 5 μm), mica (manufactured by Repco, cosmecite (muscovite) M -200, average particle diameter; 60 μm), calcium oxide (manufactured by Calcede, particles passing through 200 mesh), vinylon fiber (manufactured by Kuraray, fiber length: 3 mm),
Viscosity adjusting water, sodium oleate (manufactured by Wako Pure Chemical Industries),
A silicone-based foam stabilizer (F345, manufactured by Shin-Etsu Chemical Co., Ltd.) and dimethyl silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed and stirred with a hand mixer to prepare uniform pastes of various formulations.

Thereafter, a predetermined amount of a 20% by weight aqueous hydrogen peroxide (manufactured by Mitsubishi Gas Chemical Co., diluted from 35% by weight to 20% by weight) shown in Table 1 was added to the paste.
The mixture was mixed and stirred for about 30 seconds, poured into a molding container, and left to stand. Bubbling gradually occurred, and the bubbling was completed in about 3 minutes. After completion of the foaming, the composition was cured and heated at 85 ° C. for 12 hours, further dried at room temperature for 24 hours, and finally dried at 105 ° C. for 24 hours.
D and E were obtained. The obtained inorganic porous material was measured for average continuous pore diameter and bulk specific gravity based on an evaluation method described later, and the results are summarized in Table 2.

[0049]

[Table 2]

(3) Preparation and Evaluation of Inorganic Sound Absorbing Material The five types of inorganic porous materials A, B, and
C, D, and E were cut into cylinders having a diameter of 100 mm and a height of 60 mm. Thereafter, as shown in Tables 3 and 4, various organosilicon compounds were diluted to 10% by weight with isopropanol, and a predetermined amount thereof was applied to the surface of each inorganic porous material with a brush, and dried at room temperature for 24 hours. Finally, curing and drying were performed at 105 ° C. for 24 hours to produce various inorganic sound absorbing materials. The obtained inorganic sound absorbing material was measured for the average continuous pore diameter, the bulk specific gravity, the average sound absorption coefficient, the water absorption rate, and the freeze-thaw resistance based on the evaluation method described later, and summarized in Tables 3 and 4.

[0051]

[Table 3]

[0052]

[Table 4]

Examples 5 to 8, Comparative Examples 8 to 12 (1) Alkali treatment of inorganic porous material The inorganic porous material A obtained in the above Examples 1 to 4 and Comparative Examples 1 to 7 (2), B, C, D are 100mm in diameter x 6 height
The pieces were cut into 0 mm cylinders, immersed in 1 liter of hydrochloric acid adjusted to pH 4 with stirring, and left for 24 hours. Thereafter, the plate was immersed in 1 liter of pure water and washed well, and this was repeated three times.
It was left for 4 hours, dried, and subjected to a dealkalization treatment.

(2) Preparation of Inorganic Porous Material The inorganic porous material dealkalized in the above (1) was prepared. Thereafter, as shown in Tables 5 and 6, various organic silicon compounds were treated with isopropanol for 10 minutes. Diluted to weight percent,
A predetermined amount was applied to the surface of each inorganic porous body with a brush, dried at room temperature for 24 hours, and finally cured and dried at 105 ° C. for 24 hours to produce various inorganic sound absorbing materials. The obtained inorganic sound absorbing material is based on an evaluation method described later,
The average continuous pore diameter, bulk specific gravity, average sound absorption, water absorption, and freeze-thaw resistance were measured and summarized in Tables 5 and 6.

[0055]

[Table 5]

[0056]

[Table 6]

Evaluation method (a) Continuous pore diameter A cube having a side of 50 mm was cut out from an inorganic porous material,
A reflection type micrograph in which the plane and both sides were magnified 13 times was taken. On the above photo, draw two straight lines that are perpendicular to each other and parallel to the ridge line of each surface, and individually continue the distance from any pore membrane to the point where the next pore membrane is cut along one straight line The same operation is performed for the second straight line. The total distance is counted
) Was defined as the continuous pore diameter of this surface. The distance was measured and converted on a scale stamped on a slide of a reflection microscope. As the numerical value of the continuous pore diameter used in the present invention, the average value of the continuous pore diameter in the vertical, horizontal, and height directions of the inorganic porous body was used.

(B) Bulk Specific Gravity ρf The inorganic porous material was cut into a cylinder having a diameter of 100 × thickness of 60 mm, its weight W ₀ was measured, and calculated by dividing it by its volume V ₀ . That is, the bulk specific gravity ρf = W ₀ / V ₀

[0059] From (c) water absorption W _AR inorganic sound absorbing material, by cutting the sample cylinder diameter 100 × 60 mm, weighed W _0, and thereafter, below the surface 1
After immersion in 0 mm for 24 hours, the water adhering to the surface was lightly wiped off with a filter paper, and then the weight W was measured. The weight difference (W-W ₀ ) before and after water absorption was divided by the porosity P of the sample to obtain a volume%
Displayed with. The porosity P of the sample was measured by a helium pycnometer (manufactured by Shimadzu Corporation) and the true specific gravity ρ of the inorganic sound absorbing material was used.
_m was measured and determined by the following equation. That is, the porosity P = 1−
(Bulk specific gravity ρf / true specific gravity ρ _m) water absorption _{W AR = (W-W 0} ) / P

(D) Average sound absorption coefficient The normal incident sound absorption coefficient was measured in accordance with JIS A 1405, and a cylindrical inorganic sound absorbing material sample having a diameter of 100 and a height of 60 mm was closely attached to a steel disk having a thickness of 25 mm. The measurement was performed without an air layer. Sound frequency is 400-4000H
z, the vertical incidence sound absorption coefficient a _j for each frequency shown in Table 7 is actually measured, and multiplied by the weight k _j for each frequency,
The average sound absorption was calculated according to the following equation. Average sound absorption coefficient = Σa _j k _j / Σk _j

[0061]

[Table 7]

(E) Freezing and thawing resistance Sample (inorganic sound absorbing material) according to JIS A 1435
Was frozen in air and then thawed in water.
Performed continuously for 0 cycles. The sample after the test was dried in the air, and its appearance was visually observed.

[0063]

Since the inorganic sound absorbing material of the present invention is constituted as described above, it is excellent in water resistance and freeze-thaw resistance (or freezing-thaw resistance, even though it is a porous body having a high sound absorption property). (Destructibility), it can be very suitably used as a nonflammable interior material and exterior material in the field of construction.

Claims (2)

[Claims] 1. Amorphous SiO_Two-Al_TwoO_ThreeSystem powder,
Made from Lucari metal silicate and water, continuous pore size
Is 0.05 to 0.3 mm in the inorganic porous material, the following
When the amount of the organosilicon compound represented by the general formula [1] is 0.03 to
0.1 g / cm ^TwoInorganic characterized by being applied
Quality sound absorbing material.(R₁Is an alkyl group having 1 to 16 carbon atoms, R_TwoIs 1 carbon
To 5 alkyl groups, n is a natural number of 1 to 20) 2. After the inorganic porous body is subjected to a dealkalization treatment,
When the organosilicon compound represented by the general formula [1] is 0.01 to
Inorganic sound absorbing material according to claim 1, wherein the 0.1 g / cm ² is applied.