JPH11350434A - Self stain-proof sound absorbing material, manufacture thereof, and sound absorbing structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide self stain-proof sound absorbing material having excellent sound absorbing performance and stain-proof performance and its manufacturing method, and a sound absorbing structure such as a soundproof wall or outer facing material formed by the use of such self stain-proof sound absorbing material. SOLUTION: This is a self stain-proof sound absorbing material A made of an inorganic fiber sheet 1 of bulk density of 0.2-2 g/cm<3> having a stain-proof layer in which photocatalyst is supported at least on one face. The manufacturing method of the self stain-proof sound absorbing material is constituted so that the photocatalyst is supported with the surface of the inorganic fiber, next the inorganic fiber is molded into a nearly uniform flat sheet, and a porous supporting plate 2 made of metal plate is stuck on the one face of the obtained inorganic fiber sheet 1. Further, the sound absorbing structure is constituted so that the one part or the whole part of a structure main body is constituted of such self stain-proof sound absorbing material A, and the stain-proof layer of the sound absorbing material is faced at least the noise incoming side of the structure main body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-fouling sound-absorbing material having a pollution-preventing performance by itself and a sound-absorbing structure formed by using this sound-absorbing material. For soundproof wall materials that are attached to the inner walls and ceilings of roads, tunnels, or ground side walls of elevated expressways to prevent noise from vehicles, etc., or exterior materials that are attached to the surfaces of these soundproof wall materials. The present invention relates to a useful self-fouling sound absorbing material and a sound absorbing structure.

[0002]

2. Description of the Related Art Conventionally, various measures to prevent noise have been taken on arterial roads and highways, etc., through which traffic flows through urban areas, in order to maintain the living environment of the local residents from noise originating from vehicles and the like. I have.

[0003] As a method of such noise prevention measures,
There are a method using a street tree, a method using a soundproof wall formed using various sound absorbing boards and sound absorbing materials, and a method using a soundproof fence formed of a transparent plastic plate material in consideration of sunshine. The living environment of residents has been greatly improved.

[0004] However, such a noise source on a highway or an expressway is generally a source of exhaust gas because it is generated by a vehicle or the like. In particular, the noise source is formed by using a sound absorbing plate or a sound absorbing material. In the case of soundproof walls and exterior materials that have been made, though varying in degree, they are gradually contaminated by sulfur oxides, nitrogen oxides, and even pollutants such as oils, and as clogging and the like progress The sound absorbing performance is reduced, and furthermore, it causes corrosion.

[0005] In particular, in the case of an exterior material attached to the inner wall or ceiling of the tunnel, the ventilation method inside the tunnel is limited, so that exhaust gas is difficult to escape, and the sound absorbing plate and the sound absorbing material constituting the exterior material are contaminated. There is a problem that the sound absorbing performance is easily lowered due to clogging or the like.

In addition, soundproof walls and exterior materials used to prevent noise on highways and highways are installed in places where there is a large amount of traffic, and special vehicles and tools are used for cleaning. In some cases, these cleaning operations require a great deal of labor, and there is a problem that maintenance of these soundproof walls and exterior materials and maintenance of the sound absorbing performance thereof require a lot of labor.

[0007]

Therefore, the present inventors have simply demonstrated excellent sound absorbing performance for soundproof walls and exterior materials for noise prevention measures used on highways and highways. In addition to the sound absorbing material, it is easy to maintain and maintain the sound absorbing performance, and it can be made maintenance-free depending on the installation location etc. and the sound absorbing structure such as soundproof wall and exterior material formed using this As a result of intensive studies, a self-contamination-resistant sound-absorbing material in which an antifouling layer supporting a photocatalyst is provided on an inorganic fiber sheet having a predetermined bulk density and a sound-absorbing structure using the same have been completed, and the present invention has been completed.

Accordingly, it is an object of the present invention to provide a self-contaminating sound-absorbing material having excellent sound-absorbing performance and contamination-preventing performance. Another object of the present invention is to provide a method for producing such a self-contaminating sound absorbing material. A further object of the present invention is to provide a sound-absorbing structure such as a soundproof wall or an exterior material formed using such a self-contaminating sound-absorbing material.

[0009]

That is, the present invention provides a self-contaminating sound-absorbing material composed of an inorganic fiber sheet having a bulk density of 0.2 to 2 g / cm ³ and having a contamination preventing layer having a photocatalyst supported on at least one surface. It is.

The present invention also relates to a method of supporting a photocatalyst on the surface of an inorganic fiber, forming the inorganic fiber into a substantially uniform and flat sheet, and forming a porous support made of a metal plate on one surface of the obtained inorganic fiber sheet. This is a method for producing a self-contaminating sound absorbing material to which a plate is attached.

Further, according to the present invention, a part or the whole of the structure body is constituted by such a self-contaminating sound-absorbing material, and the above-mentioned sound absorbing material contamination prevention layer is provided on at least the noise incident side of the structure body. It is a sound absorbing structure.

The inorganic fibers used in the present invention include:
There is no particular limitation as long as it can support a photocatalyst, for example, glass fiber, rock wool, inorganic fiber such as carbon fiber, aluminum fiber made of aluminum or aluminum alloy, stainless fiber, metal fiber such as copper fiber and the like. But it is lightweight and
An aluminum fiber which is installed in a polluted environment, exhibits excellent corrosion resistance, and is excellent in workability and economic efficiency is preferable.

The inorganic fiber preferably has a fiber diameter of 50 to 300 μm, preferably 70 to 150 μm. If the inorganic fiber is thinner than 50 μm, a bulk density and a porosity required for an inorganic fiber sheet are obtained. In some cases, the desired sound absorption performance may not be obtained.
If it exceeds 00 μm, it becomes difficult to form a sheet, and it becomes difficult to produce an inorganic fiber sheet having desired physical properties.

The inorganic fiber sheet produced using such an inorganic fiber has a bulk density of 0.2 to 2 g / cm ³ , preferably 0.2 to 0.5 g / cm ³ .
It must be in the range of cm ³ . This bulk density is 0.2g
When the density is lower than / cm ³ , the inorganic fiber sheet becomes too coarse, causing a problem in carrying the photocatalyst particles, and a problem that the sound absorption efficiency is greatly reduced. If it exceeds 2 g / cm ³ , the desired porosity cannot be achieved, causing a problem that the binder is clogged and the sound is reflected. When examining by replacing the bulk density of this inorganic fiber sheet with the porosity,
It is about 30 to 95%, preferably about 85 to 95%.

Regarding the thickness of the inorganic fiber sheet,
Although not particularly limited, in the relationship between the thickness of the inorganic fiber sheet and the sound absorbing efficiency, when the bulk density of the inorganic fiber sheet is constant, the sound absorbing efficiency tends to increase as the thickness of the inorganic fiber sheet increases. Therefore, it may be determined in consideration of how much the sound absorbing effect needs to be achieved in relation to the application and the product cost.

In the present invention, the photocatalyst supported on such an inorganic fiber sheet is excited by the photoelectric effect when irradiated with ultraviolet light of 400 nm or less out of sunlight, fluorescent light or mercury lamp, It must function as a strong oxidizing catalyst for pollutants such as sulfur oxides and nitrogen oxides, and oils. For example, zinc oxide, zirconium oxide, tungsten oxide, vanadium oxide, oxide Metal oxides such as titanium are known,
In particular, anatase-type titanium oxide is preferred because it is excited under sunlight and has excellent photoactivity.

The photocatalyst only needs to be supported on at least one surface of the inorganic fiber sheet to form a pollution prevention layer. Even if the photocatalyst is supported on the entire surface of the inorganic fiber sheet, the inorganic fiber itself is not covered with the photocatalyst. It may be coated.

Accordingly, the method of forming a pollution prevention layer by supporting a photocatalyst on an inorganic fiber sheet is not particularly limited. For example, first, inorganic fibers are formed into a substantially uniform and flat sheet, The photocatalyst may be supported on one or both sides by an appropriate method such as thermal spraying, spraying, chemical film formation, sputter deposition, vacuum deposition, coating, etc. Agent,
A photocatalyst may be previously supported on the surface of the inorganic fiber using a photocatalyst composition prepared by blending a paint, a solvent, and the like, and then the inorganic fiber may be formed into a substantially uniform and flat sheet.

In the present invention, the inorganic fiber sheet having such a photocatalyst contamination preventing layer can be used as it is as a self-contaminating sound absorbing material. When a sound absorbing material is required, a porous support plate made of a metal plate having a large number of through holes and having a porosity of 30% or more, preferably about 50 to 80%, is preferably attached to one or both surfaces thereof. The porous support plate is preferably used to impart desired rigidity and strength to the self-contaminating sound absorbing material. If the porosity of the porous support plate is lower than 30%, it is not possible to secure sufficient air permeability in the obtained self-contaminating sound absorbing material, and as a result, it is not possible to exhibit desired sound absorbing performance. .

This porous support plate has a large number of through-holes of various shapes such as circular, square, rhombic, hexagonal, elliptical, and other simple designs and pictures, and has an opening ratio of 30%.
Any material that can be stuck to the inorganic fiber sheet may be used. However, from the viewpoint of the porosity and the penetration of the fiber into the porosity, the plate thickness is preferably 0.4 to 5 mm, and more preferably 0.4 to 5 mm. It is preferably a porous aluminum thin plate of 5 to 3 mm made of aluminum or aluminum alloy.

The method of attaching the porous support plate to the inorganic fiber sheet is only required to ensure that the inorganic fiber sheet and the porous support plate are firmly bonded and that the inorganic fiber sheet has sufficient air permeability. Although not particularly limited, the following methods can be preferably exemplified.

That is, an appropriate adhesive is applied to the back surface of the porous support plate, and the porous support plate and the inorganic fiber sheet are pressed and fixed under a predetermined pressure. A photocatalyst composition prepared by blending a solvent or the like is previously attached to the surface of the inorganic fiber, and a certain amount of the inorganic fiber and a porous support plate are supplied between a pair of rollers.
A method in which the inorganic fibers are formed into a sheet and simultaneously fixed on the porous support plate is exemplified.

The self-fouling sound-absorbing material of the present invention thus formed has a predetermined bulk density, has excellent sound absorbing performance itself, and has a photocatalyst supported on at least one surface thereof. When irradiated with ultraviolet light having a wavelength of 400 nm or less out of light such as sunlight, a fluorescent lamp, or a mercury lamp, the photocatalyst is excited by a photoelectric effect, and is contaminated with sulfur oxides, nitrogen oxides, and contaminants such as oils. It functions as a catalyst that exerts a strong oxidizing action and oxidizes and decomposes these pollutants.

Further, since the self-contaminating sound-absorbing material of the present invention is formed of an inorganic fiber sheet having a predetermined bulk density, the noise arriving at the self-contaminating sound-absorbing material is reduced within the inorganic fiber sheet. In addition to being attenuated while being diffusely reflected at the surface, sound is efficiently absorbed, and ultraviolet light from the light source that reaches the self-contaminant sound absorbing material is also diffusely reflected in the inorganic fiber sheet in the same manner as noise, even if the surface is not facing the light source. Even the supported photocatalyst is efficiently irradiated with ultraviolet rays, and the supported photocatalyst is efficiently excited to exert an excellent oxidizing action on pollutants as a whole.

Therefore, according to the self-contaminating sound-absorbing material of the present invention, if it has a predetermined thickness and a predetermined rigidity and strength, it can provide itself with excellent sound absorbing performance and self-cleaning properties. It can be used as a soundproof wall with antifouling performance, and if it has a relatively thin thickness, it is installed as an exterior material on the noise generation source side of the frame of the conventional soundproof wall, and the noise is reduced by this exterior material. To improve the sound-absorbing performance of the sound-insulating wall by simultaneously reaching the conventional sound-absorbing materials such as glass wool and rock wool provided in the frame body. Contamination can be prevented, and self-contamination performance against adhering contaminants can be exhibited.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below based on embodiments shown in the accompanying drawings.

Example 1 [Preparation of photocatalyst composition] Titanium particles of anatase type crystal [trade name: STK-03, manufactured by Ishihara Sangyo Co., Ltd., average primary particle diameter 7]
nm, containing 10% by weight of an inorganic binder] with a solvent (alcohol and water) to prepare a photocatalyst composition (paint) having a solid content concentration of 5% by weight, which is filled in a general paint spraying apparatus. And prepared for painting.

[Production of Aluminum Fiber Sheet] On the other hand, an aluminum alloy (JIS A 1070) was melted and solidified into a fibrous form to prepare a cotton-like aluminum fiber having a fiber diameter of 100 μm. Next, a predetermined amount of the aluminum fiber is weighed and supplied between a pair of rollers having a gap of 1.5 mm, pressed to form a substantially uniform sheet, and an aluminum fiber sheet having a thickness of 1.5 mm is formed. Prepared.

[Preparation of Self-Staining Antifouling Soundproofing Material] The above-mentioned photocatalyst composition paint was sprayed onto the surface of the aluminum fiber sheet obtained above, and then the solvent was dried. Next, it is made of aluminum alloy (JIS A 1070) and has a thickness of 0.8 mm
With a size of 1000 mm x 1000 mm and a porosity of 5
The above-mentioned photocatalyst composition paint is applied as an adhesive to an 8% porous aluminum thin plate, an aluminum fiber sheet supporting the above photocatalyst is superimposed on the paint, and again supplied between a pair of rollers having a gap of 1.5 mm. The perforated aluminum thin plate and the aluminum fiber sheet are fixed, and as shown in FIGS. 1 and 2,
Aluminum fiber sheet 1 with bulk density of 0.27 (porosity 90%)
The self-contaminating sound-absorbing material A of Example 1 comprising the porous aluminum sheet 2 having a large number of through-holes 3 was manufactured.

Example 2 In the same manner as in Example 1 described above, a self-contaminating sound absorbing material B of Example 2 comprising an aluminum fiber sheet having a bulk density of 0.32 and a porous aluminum thin plate having a large number of through holes was produced. did.

Example 3 In the same manner as in Example 1 described above, a self-contaminating sound-absorbing material C of Example 3 comprising an aluminum fiber sheet having a bulk density of 0.38 and a porous aluminum thin plate having a large number of through holes was produced. did.

[Measurement of Normal Incidence Sound Absorption Coefficient]
Regarding the self-contamination-resistant sound absorbing materials A to C obtained in Step 3, the sound absorption effect of the photocatalyst-supported sound absorbing material and the sound absorption coefficient characteristics with respect to the frequency were measured according to JIS A14.
05. The results are shown in FIG.

[Measurement of NO ₂ Gas Decomposition Performance] A test piece having a size of 5 cm × 5 cm was cut from the self-contaminating sound-absorbing material A obtained in Example 1 above, and was cut into a size of 20 cm × 20 cm × 50.
It was placed in a sealable glass container having a size of 20 cm (capacity: 20 liters), and then NO ₂ gas was introduced into the glass container so that the NO ₂ concentration became 5 ppm. next,
This glass container is placed in a dark room, and a fluorescent lamp (1 mW / cm
² ) is turned on for 15 minutes, and then NO ₂ in the glass container
The concentration was measured. As a result, the NO ₂ gas concentration was 1.5 ppm.
Reduced to.

Example 4 As shown in FIG. 4, a commercially available sound absorbing material 6 made of glass wool is placed in a frame 5 and the self-contaminating sound absorbing material A obtained in Example 1 is covered on the entire surface. To form a sound absorbing structure 4. The plurality of sound absorbing structures 4 thus obtained
And the sound absorbing plate W was configured such that the self-contaminating sound absorbing material A faces the noise generation source side. As a result of examining the obtained sound absorbing plate W for its sound absorbing performance and self-contamination performance, the internal glass wool improves the sound absorption coefficient in a wide frequency band and prevents clogging by the self-contamination-preventive sound absorbing material A carrying a photocatalyst. In each case, satisfactory results were obtained.

[0035]

The self-fouling sound-absorbing material of the present invention not only exhibits excellent sound-absorbing performance, but also has a function of decomposing pollutants and exhibits self-fouling performance. It is easy to maintain and maintain sound absorption performance, and it can be made maintenance-free depending on the installation location. For example, a sound absorbing structure such as a sound absorbing plate or exterior material for noise prevention measures used on arterial roads, highways, etc. Is extremely useful in forming

Further, the sound absorbing structure formed by using such a self-contaminating sound absorbing material is capable of removing sulfur oxides, nitrogen oxides, and contaminants such as oils from the self-contaminating sound absorbing material. Adhesion can be reduced as much as possible, and its sound absorbing performance and aesthetics can be maintained over a long period of time, and workability such as cleaning work can be significantly improved.

[Brief description of the drawings]

FIG. 1 is a front view of a self-contaminating sound absorbing material A obtained in Example 1. FIG.

FIG. 2 is a rear view of FIG. 1;

FIG. 3 is a graph showing the normal incidence sound absorption coefficients of the self-contaminating sound absorbing materials A to C obtained in Examples 1 to 3.

FIG. 4 is a partial cross-sectional explanatory view showing a sound absorbing plate W assembled by a sound absorbing structure formed using the self-contaminant sound absorbing material A of FIG.

[Explanation of symbols]

A: a self-contaminating sound absorbing material, W: a sound absorbing plate, 1: an aluminum fiber sheet, 2: a porous aluminum thin plate, 3: a transparent hole, 4: a sound absorbing structure, 5: a frame, and 6: a glass wool sound absorbing material.

Claims (8)

[Claims] 1. A least self antifouling sound absorbing material on one surface photocatalyst is characterized in that it consists of inorganic fiber sheet having a bulk density of 0.2 to 2 g / cm ³ with a pollution layer supported. 2. The self-contaminating sound-absorbing sound absorbing member according to claim 1, wherein a porous supporting plate comprising a metal plate having a large number of through holes and having a porosity of 30% or more is adhered to at least one surface of the inorganic fiber sheet. Wood. 3. The inorganic fiber sheet has a fiber diameter of 50 to 300.
The self-contaminating sound-absorbing material according to claim 1, wherein a metal fiber of μm is formed into a sheet. 4. The metal fiber sheet is an aluminum fiber sheet made of aluminum or an aluminum alloy.
The self-contaminating sound-absorbing material according to 1. 5. The photocatalyst is zinc oxide, zirconium oxide,
The self-contaminating sound-absorbing material according to any one of claims 1 to 4, which is a metal oxide selected from tungsten oxide and titanium oxide. 6. The self-contaminating sound-absorbing material according to claim 2, wherein the porous support plate is formed of a porous aluminum thin plate having a thickness of 0.4 to 5 mm and made of aluminum or an aluminum alloy. 7. A photocatalyst is supported on the surface of the inorganic fiber, and then the inorganic fiber is formed into a substantially uniform and flat sheet, and a porous support plate made of a metal plate is attached to one surface of the obtained inorganic fiber sheet. A method for producing a self-fouling sound-absorbing material. 8. A part or all of a structure main body is constituted by the self-contaminating sound-absorbing material according to any one of claims 1 to 6, and contamination of the sound absorbing material at least on a noise incident side of the structure main body. A sound-absorbing structure, wherein the prevention layer faces.