JPH10245905A - Sound absorbing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sound absorbing material having both excellent sound absorption and excellent strength by laminating one continuous permeable hole foamed body with the ventilation resistance of the specified value over one surface of different continuous permeable hole foamed body. SOLUTION: A continuous permeable hole foamed body B formed of hardenable inorganic composition whose permeability resistance at 50cm/s in the air speed is 1-5Pa.s/cm<2> is laminated over one surface of a continuous permeable hole foamed body A formed of the hardenable inorganic composition. The foamed body B is 1-10mm in foam diameter, 0.1-5mm in cell wall thickness between foams, and 0.2-0.5g/cm<3> in bulk density, and the lamination thickness over the foamed body A is preferably 2-40mm. The hardenable inorganic composition used for the foamed body B preferably consists of Al2 O3 -SiO2 inorganic powder, alkali metal silicate, foaming agent, water, and polysiloxane- polyoxyalkylene copolymer. Both excellent sound absorption and excellent strength are obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound-absorbing material, and more particularly to a sound-absorbing material having excellent sound absorbing properties and having high strength and useful for non-combustible civil engineering and building materials.

[0002]

2. Description of the Related Art Conventionally, inorganic foams have been widely used as non-combustible civil engineering and building materials because of their excellent light weight and heat insulation. However, these inorganic foams generally consist of closed cells, and their performance as a sound absorbing material is low and small. As the inorganic sound absorbing material, for example, Japanese Unexamined Patent Publication No. 5-85858 discloses a main material comprising a water-soluble alkali metal silicate, an inorganic solid component, and a filler, and a foaming agent such as an anionic surfactant and hydrogen peroxide. There is disclosed an inorganic foam having open cells which can be foamed and cured using the composition for an inorganic foam to be used for a sound absorbing material, a filter and the like.

However, the sound-absorbing material disclosed in Japanese Patent Application Laid-Open No. 5-85858 has a low density and a high air permeability of the foam in order to obtain high sound absorbing properties. There was a problem of doing it. For example, it is used for a large-area wall such as a soundproof wall of a highway or the like, and is generally washed with high-pressure washing water when removing dirt from the sound-absorbing material. When hitting the sound-absorbing material, the surface of the sound-absorbing material is ragged, so that there is a problem of tradeoff between sound absorbing property and strength.

In an attempt to achieve both the mechanical strength of the lightweight cellular concrete plate surface and various properties such as heat insulation and light weight, a lightweight cellular concrete plate having a specific gravity gradient in the thickness direction of the plate has been proposed. Manufacturing methods have been proposed. For example, Japanese Patent Application Laid-Open No. 8-208345 discloses a method for producing a lightweight cellular concrete plate having a specific gravity gradient by injecting a low specific gravity mortar slurry and a high specific gravity mortar slurry and performing form vibration.

[0005] However, in the method disclosed in Japanese Patent Application Laid-Open No. 8-208345, bubbles generated during foaming are partially crushed by the vibration of the mold, so that the specific gravity of the high specific gravity layer is 0.7 to 0.7.
The light-weight cellular concrete plate adjusted to about 1.3 and having a low sound-absorbing property has a low sound-absorbing property, so that a sound-absorbing material cannot be manufactured by such a method.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above facts, and its object is to
An object of the present invention is to provide a sound absorbing material having both high sound absorbing properties and strength.

[0007]

According to the first aspect of the present invention,
One surface of the continuous pore foam (A) molded from the curable inorganic composition has a ventilation resistance of 0.
The gist of the present invention is a sound-absorbing material characterized in that a continuous pore foam (B) formed from a curable inorganic composition having a pressure of 1 to 5 Pa · s / cm ² is laminated.

[0008] The curable inorganic composition used in the continuous pore foam (A) in the present invention is not particularly limited as long as it can form a continuous pore foam. ) Al ₂ O ₃ -SiO ₂ based inorganic powders, (b) an alkali metal silicate, (c) setting inorganic composition comprising blowing agent and (d) water is preferably used.

(A) Al_TwoO_Three-SiO_TwoSystem mineral
As powder, Al_TwoO_Three90 to 10% by weight, SiO_Two
A powder having a composition of 10 to 90% by weight is used. Up
Al of the above composition_TwoO_Three-SiO_TwoAs the inorganic powder,
For example, dust and flour when producing alumina-based abrasives
Classified and crushed products of ash and fly ash, metaca
Obtained by melting and spraying orin and fly ash
Powder, Al _TwoO_Three-SiO_TwoDissolve clay made of system powder
Powder obtained by spraying into molten air, Al_TwoO_Three-SiO
_TwoPowder obtained by applying mechanical energy to system powder
Powder obtained by heating body and clay minerals at 500-900 ° C
Powder obtained by applying mechanical energy to the body is used.
It can be used, but it is limited to these if you select the composition and particle size
Not.

The above (a) alkali metal silicates include:
General formula M ₂ O.nSiO ₂ (M = Li, K, Na or a mixture thereof, the value of n is preferably n = 0.05 to
8, more preferably n = 0.1 to 3). When the value of n of the alkali metal silicate exceeds 8, the alkali metal silicate aqueous solution is apt to gel,
Immediately the viscosity sharply rises, making it difficult to mix with other powders. If it is less than 0.05, the strength of the obtained open-cell foam decreases, so that the alkali metal silicate in the above range is used.

When the alkali metal silicate is mixed with other powder components to prepare a curable inorganic composition, it is preferably added and mixed as an aqueous solution. The aqueous solution concentration of the alkali metal silicate is not particularly limited, but if the concentration is high, a viscosity suitable for foaming cannot be obtained,
If the concentration is low, the curing shrinkage of the obtained open-cell foam may increase or the strength may decrease.
60% by weight is preferred.

The amount of the alkali metal silicate to be added depends on the amount of the hydraulic inorganic substance 1 such as the Al ₂ O ₃ —SiO ₂ inorganic powder.
The amount is preferably 0.2 to 450 parts by weight, more preferably 10 to 350 parts by weight, per 100 parts by weight. When the addition amount of the alkali metal silicate is less than 0.2 parts by weight,
The resulting open-cell foam is poorly cured, and conversely, 45
If the amount exceeds 0 parts by weight, the water resistance of the obtained open-cell foam may be reduced.

The foaming agent (C) is not particularly limited, and examples thereof include peroxides and metal powders.

The above-mentioned peroxide foaming agents include, for example,
Examples include hydrogen peroxide, sodium peroxide, potassium peroxide, sodium perborate and the like. The amount of the foaming agent composed of these peroxides is preferably 0.01 to 1 part by weight per 100 parts by weight of the hydraulic inorganic substance of the curable inorganic composition.
0 parts by weight. If the addition amount is less than 0.01 part by weight, bubbles are not sufficiently formed, and it is difficult to obtain a desired foam. There is.

When hydrogen peroxide is used as a foaming agent, it is preferable to use hydrogen peroxide in an aqueous solution. When the concentration of the aqueous solution is too high, foaming becomes severe and dangerous, and stable foaming becomes difficult. The viscosity is preferably 0.5 to 35% by weight, more preferably 1 to 25% by weight, since the viscosity of the curable inorganic composition decreases and stable foaming becomes difficult.

As the metal powder-based foaming agent, for example,
Mg, Ca, Cr, Mn, Fe, Co, Ni, Cu, Z
n, Al, Ga, Sn, Si, ferrosilicon and the like. If the average particle size of these metal powder-based foaming agents is too small, the dispersibility in the curable inorganic composition may be reduced, and if the dispersibility is good, the reactivity becomes high, and foaming may occur. Vigorous and stable foaming becomes difficult, and if it is too large, the reactivity decreases, and it may become difficult to obtain a desired foam.
It is. The addition amount of these metal powder-based foaming agents is based on 100 parts by weight of the hydraulic inorganic substance of the curable inorganic composition.
Preferably it is 0.01 to 5 parts by weight. If the addition amount is less than 0.01 part by weight, bubbles are not sufficiently formed, it is difficult to obtain a desired foam, and if it exceeds 5 parts by weight,
The foaming gas becomes excessive, and there is a possibility that a lot of foam breakage is generated.

The type and amount of these foaming agents are appropriately selected and set based on the specifications of the target product. However, cost, safety during use, easy availability, easy handling, and the like are comprehensive. In particular, hydrogen peroxide and aluminum powder are preferably used.

The water (d) contained in the curable inorganic composition includes a water-soluble inorganic material such as the Al ₂ O ₃ —SiO ₂ -based inorganic powder, including the water component in the alkali metal silicate aqueous solution. 35 to 1 parts by weight, preferably
500 parts by weight, more preferably 45 to 1000 parts by weight. When the water content increases, the viscosity of the curable inorganic composition decreases, the foaming process becomes unstable, and the strength of the obtained open-cell foam also decreases. Conversely, when the water content is low, the viscosity of the curable inorganic composition becomes too high, the foaming process becomes unstable, and high-magnification foaming,
A low-density open-cell foam cannot be obtained.

If necessary, the curable inorganic composition may contain an inorganic filler, a reinforcing fiber, a foaming aid, an inorganic foam, and the like. The inorganic filler is added for the purpose of improving the fluidity of the curable inorganic composition slurry, stabilizing bubbles during and after foaming, reducing shrinkage during curing of the obtained open-cell foam, and densifying cells. Is done.

Examples of the inorganic filler include porous inorganic materials such as silica sand, silica powder, fly ash, slag, silica fume, mica, talc, wollastonite, calcium carbonate, aerosil, silica gel, alumina gel, zeolite, and activated carbon. Powder.

The average particle size of the inorganic filler is preferably 0.01 μm to 1 mm. The average particle size is 0.0
If it is less than 1 μm, the viscosity of the curable inorganic composition increases due to an increase in the amount of adsorbed water, and there is a possibility that mixing workability may decrease or foaming may not be sufficiently performed. If it exceeds 1 mm, the stability of foaming will be impaired.

The amount of the inorganic filler to be added is preferably 20 to 600 parts by weight, more preferably 40 to 40 parts by weight, based on 100 parts by weight of the hydraulic inorganic substance of the curable inorganic composition.
0 parts by weight. If the amount is less than 20 parts by weight, a sufficient effect cannot be obtained. If the amount exceeds 600 parts by weight, the strength of the obtained open-cell foam may be reduced.

The reinforcing fibers are added for the purpose of improving the strength of the obtained open-cell foam and preventing cracks. Examples of the reinforcing fibers include vinylon fiber, polypropylene fiber, aramid fiber, acrylic fiber, rayon fiber,
Examples include carbon fiber, glass fiber, potassium titanate whisker, alumina fiber, steel wool, and slag wool.

The fiber length of the reinforcing fiber is preferably 1
１５15 mm. When the fiber length is less than 1 mm, the fibers are re-agglomerated at the time of mixing to form fiber balls, and the fiber length is 15 m.
If it exceeds m, the dispersibility will be reduced, and none of them may exhibit a sufficient reinforcing effect. The fiber diameter of the reinforcing fibers is preferably 1 to 500 μm. If the fiber diameter is out of the above range, there is a possibility that no sufficient reinforcing effect is exhibited.

The amount of the reinforcing fiber to be added is preferably 10 parts by weight or less based on 100 parts by weight of the hydraulic inorganic substance of the curable inorganic composition. If the addition amount exceeds 10 parts by weight, the dispersibility of the fiber is reduced, and the reinforcing effect may be impaired.

The foaming aid is added for the purpose of stabilizing bubbles during foaming. Examples of the foaming auxiliary include, for example, a porous inorganic powder such as silica gel, alumina gel, zeolite, and activated carbon, and a surfactant composed of a fatty acid metal salt such as a metal stearate, a metal oleate, and a metal palmitate. Is mentioned. Among the foaming aids comprising the above surfactants, among others, zinc stearate, calcium stearate, aluminum stearate, sodium oleate, potassium oleate, sodium palmitate,
Potassium palmitate, sodium laurylbenzenesulfonate, and sodium lauryl sulfate can be suitably used.

The addition amount of the foaming aid composed of the porous inorganic powder is determined by the amount of the hydraulic inorganic material 100 of the curable inorganic composition.
It is preferably 5 parts by weight or less based on parts by weight. If the amount exceeds 5 parts by weight, the occurrence of foam breakage increases,
Foaming stability is impaired. The addition amount of the foaming aid composed of the surfactant is preferably 0.05 to 5 parts by weight, more preferably 0.3 to 3 parts by weight, based on 100 parts by weight of the hydraulic inorganic substance of the curable inorganic composition. Department. When the addition amount is less than 0.05 part by weight, the effect of adding the foaming aid does not appear, the occurrence of foam breakage increases, and the stability of foaming may be impaired. If the amount exceeds the above range, the viscosity of the curable inorganic composition may increase, which may adversely affect the foaming of the curable inorganic composition.

The inorganic foam is added for the purpose of reducing the weight of the obtained open-cell foam. Examples of the inorganic foam include a glass balloon, a shirasu balloon, a fly ash balloon, a silica balloon, a pearlite,
Hill stone, granular expanded silica, and the like. These may be used alone or in combination of two or more. When the apparent density of the inorganic foam is less than 0.01 g / cc, the mechanical strength of the obtained open-cell foam is reduced. When the apparent density is more than 1 g / cc, the purpose of reducing the weight is sufficiently achieved. Therefore, preferably 0.01 to 1 g / c
c, more preferably 0.03 to 0.7 g / cc.
The amount of the inorganic foam added is preferably 10 to 10 parts by weight of the hydraulic inorganic substance of the curable inorganic composition.
100 parts by weight, more preferably 30 to 80 parts by weight. If the amount is less than 10 parts by weight, the purpose of reducing the weight cannot be sufficiently achieved, and if it exceeds 100 parts by weight, the mechanical strength of the obtained open-cell foam may be reduced.

The foaming means for forming the open-cell foam from the curable inorganic composition is not particularly limited. For example, a foaming agent such as a peroxide or a metal powder is used, And the like.

In the present invention, the continuous pores of the inorganic continuous pore foam refer to the individual cells in the closed cell foam in which small cells (cells) are gathered, in the longitudinal direction of the closed cell foam. It refers to a thin and long bubble as if cells adjacent to each other were broken one after another, and the continuous pore diameter indicates the diameter of the continuous pore. The average continuous pore diameter of the inorganic continuous pore foam (A) is preferably 1
0 to 5000 μm, more preferably 50 to 1000 μm
It is. If the average value of the continuous pore diameter of the inorganic continuous pore foam (A) is out of the range of 10 to 5000 μm, the sound absorbing property is reduced.

The air permeability of the continuous pore foam (A)
Is 1cm^Three・ Cm / cm^Two・ Sec ・ cmH_TwoLess than O
If there is, the sound absorption will decrease, 40cm^Three・ Cm / cm^Two・
sec.cmH_TwoIf it exceeds O, in addition to a decrease in sound absorption,
Since the mechanical strength of the open-cell foam itself decreases,
The air permeability of the continuous pore foam (A) is preferably 1 to 4
0cm^Three・ Cm / cm^Two・ Sec ・ cmH_TwoO, better
Preferably 3-20cm ^Three・ Cm / cm^Two・ Sec ・ cm
H_TwoO, most preferably 5-10 cm^Three・ Cm / cm^Two
・ Sec ・ cmH_TwoO.

Further, the continuous pore foam (B) of the present invention comprises:
It is formed by foaming and curing a curable inorganic composition, and has a ventilation resistance of 0.1 to 5 at a wind speed of 50 cm / s.
What has Pa · s / cm ² is used. The airflow resistance at a wind speed of 50 cm / s of the continuous vent foam (B) is 5
If the pressure exceeds Pa · s / cm ² , the sound absorption will decrease, and
It is difficult to obtain an inorganic continuous vent foam having a ventilation resistance at 0 cm / s of less than 0.1 Pa · s / cm ² ,
Further, even if it is obtained, it has low mechanical strength, and when washed with high-pressure water, the above-mentioned laminated continuous air-permeable foam (A)
Therefore, the airflow resistance at a wind speed of 50 cm / s is more preferably 0.3 to 3 Pa · s / cm ² because the protection ability of the airflow is reduced.

The open-cell foam (B) is not particularly limited as long as it has the above-mentioned air-permeable properties. For example, the cell diameter is 1 to 10 mm, and the cell wall thickness between cells is 0.1-5mm, bulk density 0.2-0.5g / c
m is ^3, and is suitably used thickness laminated on one surface of the continuous vent foam (A) is 2 to 40 mm.

[0034] the continuous vent foam setting inorganic composition used in (B), as long as it has the above ventilation characteristics, but are not particularly limited, for example, Al ₂
O ₃ -SiO ₂ based inorganic powder 100 parts by weight, 0.2 to 450 parts by weight of alkali metal silicate, blowing agent 0.01-10
Parts by weight, 35 to 1500 parts by weight of water and polysiloxane
A curable inorganic composition composed of 0.1 to 5 parts by weight of a polyoxyalkylene copolymer is suitably used.

The above-mentioned polysiloxane-polyoxyalkylene copolymer is used for foaming the curable inorganic composition (B) to increase the cell diameter and form a continuous pore foam. When the addition amount of the polysiloxane-polyoxyalkylene copolymer is less than 0.1 part by weight,
When the cell diameter is reduced, the number of closed cells increases, the airflow resistance increases, and when it exceeds 5 parts by weight, the strength of the obtained foam may decrease. Parts.

As the foamable inorganic composition other than the above-mentioned polysiloxane-polyoxyalkylene copolymer, components corresponding to the above-mentioned foamable inorganic composition (A) are similarly used.

According to the second aspect of the present invention, the cell diameter of the open pore foam (B) is 1 to 10 mm, the cell wall thickness between the cells is 0.1 to 5 mm, and the bulk density is 0.2 to 0. 2. The thickness of the continuous air-permeable foam (A) is 5 g / cm ³ and 2 to 40 mm. 3.
The described sound absorbing material is the gist.

The open-cell foam (B) has a cell diameter of 1
If it is less than 10 mm, the sound absorbing property is reduced, and if it exceeds 10 mm, the strength is reduced. The cell wall thickness between the bubbles is 0.1m
If it is less than m, the strength will decrease, and if it exceeds 5 mm, the sound absorption will decrease. Further, when the bulk density is less than 0.2 g / cm ³ , the strength is reduced, and the protective ability of the continuous pore foam (A) at the time of washing with the high-pressure water is reduced. or,
If it exceeds 0.5 g / cm ³ , the sound absorption will be reduced. / Cm
^If it exceeds ³ , the sound absorption will decrease.

The thickness of the continuous pore foam (B) is 2 m.
When the thickness is smaller than m, the strength is reduced, and the protective ability of the continuous vent foam (A) at the time of washing with the high-pressure water is reduced.
On the other hand, if it exceeds 40 mm, the sound absorbing property is reduced, so that it is limited to the above range.

According to a third aspect of the present invention, the curable inorganic composition obtained by molding the continuous pore foam (B) is made of Al ₂ O _3-
SiO ₂ inorganic powder, alkali metal silicate, foaming agent,
The sound absorbing material according to claim 1 or 2, which is a curable inorganic composition comprising water and a polysiloxane-polyoxyalkylene copolymer.

The components used in the first and second aspects of the present invention are used as the components of the curable inorganic composition obtained by molding the open-cell foam (B). The preferable addition amount of the alkali metal silicate is Al ₂ O ₃ —SiO ₂
It is 0.2 to 450 parts by weight based on 100 parts by weight of the inorganic powder. If the addition amount is less than 0.2 parts by weight, the obtained continuous pore foam will have poor curing, and if it exceeds 450 parts by weight, the water resistance of the obtained continuous pore foam may be reduced.

When a peroxide such as hydrogen peroxide is used as the foaming agent, the preferable addition amount is Al ₂
0.0 to 100 parts by weight of O ₃ —SiO ₂ based inorganic powder
It is 1 to 10 parts by weight. If the addition amount is less than 0.01 part by weight, bubbles are not sufficiently formed, and it is difficult to obtain a desired foam. There is. In the case where the metal powder aluminum powder or the like is used as the blowing agent, its preferable amount is 0.01 to 10 parts by weight with respect to Al ₂ O ₃ -SiO ₂ -based inorganic powder 100 parts by weight. If the addition amount is less than 0.01 parts by weight, bubbles are not sufficiently formed, and it is difficult to obtain a desired foam.
If the amount exceeds 0 parts by weight, the foaming gas becomes excessive, and there is a possibility that a large amount of foam is generated.

The preferable addition amount of the water is Al ₂ O
35 to 1 with respect to 100 parts by weight of the _3- SiO ₂ inorganic powder
500 parts by weight. If the addition amount is less than 35 parts by weight, the viscosity of the curable inorganic composition becomes too high, the foaming step becomes unstable, and it is difficult to obtain a high-magnification foam or a low-density continuous pore foam, and the weight is 1500 wt. When the amount exceeds the above range, the viscosity of the curable inorganic composition becomes too low, the foaming process becomes unstable, and the strength of the obtained continuous pore foam may be reduced.

Further, a preferable addition amount of the polysiloxane-polyoxyalkylene copolymer is Al ₂ O ₃ —SiO
It is 0.1 to 5 parts by weight based on 100 parts by weight of the _second inorganic powder. When the addition amount is less than 0.1 part by weight, the cell diameter becomes small, the number of closed cells increases, and the airflow resistance increases, and when it exceeds 5 parts by weight, the strength of the obtained foam decreases. There is a risk.

The means for laminating the continuous pore foam (B) on one side of the continuous pore foam (A) is not particularly limited. For example, the means for laminating the continuous pore foam (A) is as follows. A method in which the continuous vent foam (B) is overlaid on one side and the outside thereof is tightened with a sturdy frame: the continuous vent foams (A) and (B) are superimposed as described in the preceding section, and the superimposition is performed. A method of bonding the mating surfaces to each other with an adhesive such as a vinyl acetate resin adhesive or a urethane resin adhesive,
: A curable inorganic composition slurry comprising water and a hydraulic inorganic substance such as ordinary Portland cement, special Portland cement, Roman cement, magnesia cement, gypsum, lime, and a mixture thereof, instead of the adhesive in the method described in the preceding paragraph. Adhesion methods using a curable inorganic composition slurry composed of an Al ₂ O ₃ —SiO ₂ -based inorganic powder, an alkali metal silicate and water used in the invention described in Items 1 and 2 and the like.

As described above, the sound-absorbing material according to the first aspect of the present invention is obtained by laminating the continuous-porous foam (B) on the continuous-porous foam (A) and forming the continuous-porous foam (A). The surface,
Since it is protected by the continuous pore foam (B), it exhibits the high sound absorbing property of the double pore foam and the high strength due to the above-mentioned structure, and especially enables washing with high-pressure water.

The sound-absorbing material according to the second aspect of the present invention is, as described above, the cell diameter of the continuous pore foam (B), the cell wall thickness between the cells, the bulk density, and the continuous pore foam (A). Since the thickness laminated on the surface is limited to its optimum range, it shows the high sound absorbing property of the bi-continuous pore foam and the high strength by the above structure, especially the high pressure water. Cleaning by using

The sound-absorbing material according to the third aspect of the present invention has a constitution of a curable inorganic composition forming the continuous-porous foam (B) as described above. In addition to exhibiting high sound absorbing properties, the structure described above exhibits high strength, and enables cleaning with high-pressure water.

[0049]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.

[Inorganic curable powder] Fly ash (manufactured by Kanden Kako Co., Ltd., average particle size 20 μm, JIS A6201)
Was classified by a classifier (Model: TC-15, manufactured by Nisshin Engineering Co., Ltd.) to obtain an inorganic curable powder having a particle size of 10 μm or less.

[Other Materials] Talc: manufactured by Sanyo Clay Industry Co., Ltd., trade name "Talc 83",
Average particle size 5 μm. Mica: Szolite mica, average particle size 40 μm. Vinylon fiber: Kuraray Co., Ltd., trade name "RM182-
3 ", fiber length 3 mm. Sodium oleate: manufactured by Wako Pure Chemical Industries. Hydrogen peroxide: Mitsubishi Gas Chemical Company's 35% by weight product diluted to 10% by weight.

[Preparation of Continuous Aperture Foam A] The components of the curable inorganic composition except for the foaming agents shown in Table 1 were stirred and mixed with a hand mixer to form a uniform paste. still,
Sodium silicate and water were previously mixed and dissolved,
In a state of an aqueous solution having the concentration shown in (1), it was mixed with other components. Next, hydrogen peroxide used as a blowing agent shown in Table 1 was added to the curable inorganic composition paste as a 10% by weight aqueous hydrogen peroxide solution prepared by previously mixing and diluting a 35% by weight aqueous solution of hydrogen peroxide and water. In addition, about 10 more
The mixture was stirred and mixed for 2 seconds to obtain a foamable curable inorganic composition. The foamable curable inorganic composition obtained is immediately poured into a mold for molding, and when left, the foaming gradually occurs,
Foaming was completed in about 3 minutes. Then, it is heated in an oven at 85 ° C. for 12 hours, cured, and has a thickness of 8 m shown in Table 1.
m, a continuous pore foam A having a bulk density of 0.3 g / cm ³ was prepared.

[Preparation of foam with continuous open pores B] The foamable curable inorganic composition shown in Table 1 was poured into a mold.
In the same manner as the continuous pore foam A, a pore foam B having the constitution and performance shown in Table 1 was produced. The obtained open-cell foams A and B were demolded and then dried in a diphosphorus pentoxide desiccator to obtain a thickness and an apparent density (g / c).
m ³ ) was measured.

(Examples 1 to 6) Foam A having continuous open pores
On one side, a vinyl acetate resin-based adhesive was applied, and the continuous pore foam B was laminated thereon to produce a sound absorbing material.

(Comparative Example) Open-cell foam A shown in Table 1
Was used as a sound absorbing material.

[0056]

[Table 1]

In order to evaluate the performance of the sound absorbing materials of Examples 1 to 6 and Comparative Example, measurement of a normal incidence sound absorbing coefficient and a high-pressure washing water test were carried out by the following methods. The test results are shown in Table 1.

1. Normal incidence sound absorption coefficient: JIS A140
According to No. 5, the normal incidence sound absorption coefficient (aj) was measured. still,
The size of the test piece was 100 mm in diameter, and the sound-absorbing material of the example had the surface on the side of the continuous vent foam B as the sound source side. The back surface of the test piece was measured in a state in which an iron plate having a thickness of 25 mm was in close contact with the test piece and there was no air layer. The measurement of the normal incidence sound absorption coefficient (aj) is performed in the frequency range of 400 to 4000 Hz, and the measured value for each frequency is weighted using the weight Kj defined in the Road Traffic Noise Measurement Guideline of the Ministry of Construction, and the normal incidence average is measured. The sound absorption coefficient Σaj · Kj / ΣKj was calculated. Although the normal incidence average sound absorption coefficient was shown as a real number, 0.85 or more was treated as good in the evaluation in the present invention.

2. High pressure wash water test: Area obtained 500
A water-absorbing material having a size of 600 mm × 600 mm was used as a test piece, and water was discharged from a position 15 cm above the test piece at a water discharge angle of about 60 ° and a nozzle discharge pressure of 60 kg / cm ² for 15 seconds with a water amount normally used for washing, and the surface of the foam Was observed, and evaluated in two stages: ：: no damage was observed, ×: damage was found such as surface scraping.

As is clear from Table 1, the sound absorbing materials of Examples 1 to 6 all have excellent sound absorbing properties and high-pressure water washing ability. In contrast, the sound-absorbing material of the comparative example without the continuous pore foam B layer has an initial sound absorbing property,
As is clear from the results of the high-pressure cleaning water test, the surface was shaved by the cleaning with the high-pressure cleaning water and became unusable in a short period of time.

[0061]

Since the sound absorbing material of the present invention is constituted as described above, it has both high sound absorbing properties and high strength.

Claims (3)

[Claims] 1. A curable inorganic material having a ventilation resistance at a wind speed of 50 cm / s of 0.1 to 5 Pa · s / cm ² on one surface of a continuous pore foam (A) molded from a curable inorganic composition. A sound-absorbing material obtained by laminating continuous pore foams (B) molded from the composition. 2. The continuous pore foam (B) has a cell diameter of 1 to 2.
10 mm, the cell wall thickness between cells is 0.1 to 5 mm, the bulk density is 0.2 to 0.5 g / cm ³ , and the thickness laminated on one surface of the continuous pore foam (A) Is 2 to 40 mm
The sound absorbing material according to claim 1, wherein 3. The curable inorganic composition obtained by molding the continuous pore foam (B) comprises an Al ₂ O ₃ —SiO ₂ inorganic powder, an alkali metal silicate, a foaming agent, water, and a polysiloxane-polyoxy. 3. A curable inorganic composition comprising an alkylene copolymer.
The described sound absorbing material.