JPH0649348B2 - SOUND ABSORBING MATERIAL, MANUFACTURING METHOD THEREOF, AND SOUND ABSORBING BODY - Google Patents

Description

The present invention relates to a sound absorbing material, a method for manufacturing the same, and a sound absorbing body to which the sound absorbing material is applied. More specifically, a sound absorbing material using the aluminum expanded metal or resin mesh and the ethylene fluoride thin film and / or the polyvinylidene thin film, and a method for manufacturing the same, and a method for manufacturing the sound absorbing material. Applied to a sound absorber.

<Prior Art> Conventionally, the sound absorbing material is composed of various porous materials such as glass wool and aluminum porous material.

However, since these conventional sound absorbing materials are made of a porous material, they are arranged, and as time goes by, various impurities are accumulated in the pores together with water, and finally the pores become clogged, resulting in a noise absorption characteristic. Deterioration will occur.

Further, in a sound absorbing material using glass wool or the like, the effect of the binder becomes weaker over time, the glass wool is scattered, and the sound absorbing characteristics are deteriorated.

As a countermeasure against this, a bag is made of a thin film, and a porous material such as aluminum porous material or glass wool is filled therein to form a sound absorbing material. However, since many porous bodies applied to sound absorbing materials such as aluminum porous material and glass wool are soft, it is necessary to dispose a metal front plate such as punching metal to hold them. This caused an increase in construction costs.

Further, since the front plate is usually made of metal, and the aluminum porous material is made of metal, it is used as a radio wave shielding material, which may cause problems such as poor reception of television images around the sound absorbing material. Causing the problem.

Moreover, the sound absorbing material formed by this method is often used as a sound absorbing wall of a highway, but since it has a metal front plate as described above, the outside of the sound absorbing wall cannot be seen and the outside scenery can be seen. I can't see.

<Problems to be Solved by the Invention> An object of the present invention is to solve the above-mentioned problems of the prior art, and does not cause deterioration with time of sound absorbing characteristics such as a conventional sound absorbing material made of a porous material. To provide a sound absorbing material which has good sound absorbing properties for a long period of time and which can be made substantially transparent without causing problems such as various radio wave shielding obstacles, and an inexpensive and simple manufacturing method thereof. It is in.

<Means for Solving the Problems> In order to achieve the above object, the first aspect of the sound absorbing material of the present invention is a laminate of an aluminum expanded metal and an ethylene fluoride thin film and / or a polyvinylidene thin film. A sound-absorbing material is provided.

A second aspect of the sound absorbing material of the present invention is to provide a sound absorbing material, which is a laminate of a resin mesh and an ethylene fluoride thin film and / or a polyvinylidene thin film.

Further, the film thickness of the ethylene fluoride thin film and / or the polyvinylidene thin film is preferably 4 to 25 μm.

Further, the first aspect of the method for producing a sound absorbing material of the present invention is to laminate at least one ethynylene fluoride thin film and / or polyvinylidene thin film on an aluminum expanded metal, on which an aluminum expanded metal is formed. Provided is a method for manufacturing a sound-absorbing material, characterized by pressing the laminated body and pressing the aluminum expanded metal and the ethylene fluoride thin film and / or the polyvinylidene thin film after laminating.

The second aspect of the method for producing a sound absorbing material of the present invention is that at least one ethylene fluoride thin film and / or polyvinylidene thin film is laminated on a resin net, and a resin is formed on the thin film. Sound-absorbing material, characterized in that at least a part of the resin net-like body and the ethylene fluoride thin film and / or polyvinylidene thin film are adhered by a double-sided tape and / or an adhesive. A method for manufacturing the same is provided.

Further, another aspect of the present invention is characterized in that the sound absorbing material further has a sound absorbing layer composed of an air layer and / or a porous sound absorbing material layer on a downstream side in a traveling direction of sound to be shielded. Provide a sound absorber.

In the present invention, aluminum includes an aluminum alloy, and the resin may be synthetic or natural.

<Structure of Invention> Hereinafter, a specific structure of the present invention will be described in detail.

FIG. 1 shows a schematic front view of one embodiment of the first aspect of the sound absorbing material of the present invention, and FIG. 2 shows a sectional view schematically showing a section taken along line II-II thereof.

The sound absorbing material 10 in the illustrated example is pressed by a press, a roller or the like in a preferable mode with an aluminum (hereinafter referred to as Al) expanded metal 12 sandwiching a thin film 14 made of an ethylene fluoride thin film or a polyvinylidene thin film. It has a crimped configuration.

Expanded metal refers to a metal thin plate in which a large number of cuts are made and the cuts are pulled in a substantially right-angled direction to form a net, and in the present invention, an Al expanded metal made of Al or an Al alloy is used as the expanded metal. To use.

Expanded metal is not a thin metal wire braided like a metal mesh, so the cut cross section of the thin metal plate is twisted by the tensile force, which is not only perpendicular to the plane of the thin metal plate, but also twisted in parallel or oblique directions. For thin film 14
It is possible for the two Al expanded metals 12 to come into close contact with each other via the.

The thickness of the Al thin plate applied as a raw material of the Al expanded metal 12 applied to the present invention is not particularly limited,
Usually, a diameter of 0.2 mm to 1 mm is used.

In the sound absorbing material 10 of the present invention, the degree of passage of radio waves changes depending on the workability of the Al expanded metal 12, that is, the size of the above-mentioned cut of the thin metal plate and the size of the iris (opening) due to the tensile force. The larger the eyes, the better the radio wave transmission. Therefore, it may be appropriately selected according to the use of the sound absorbing material 10.

In the sound absorbing material 10 of the illustrated example, the thin film 14 is sandwiched between such Al expanded metals 12, and preferably both are pressure-bonded. The sound absorbing material 10 of the present invention obtains good sound absorbing characteristics by utilizing the film vibration of the thin film 14.

The thin curtain 14 applied to the present invention is a thin film made of an ethylene fluoride resin or a polyvinylidene resin.

Various kinds of substances can be applied as the fluoroethylene resin used in the present invention, and the following are preferable examples.

Tetrafluoroethylene (PTFE) Ethylene tetrafluoride / propylene hexafluoride copolymer Tetrafluorinated ethylene / polyethylene copolymer (ETFE) Trifluoroethylene chloride (PCTFE) These fluoroethylene-based resins are nonflammable and have excellent chemical resistance, weather resistance, and heat resistance.

Further, as the polyvinylidene-based resin, the following are preferably exemplified.

Vinylidene difluoride (PVDF) Vinylidene cyanide These vinylidene resins are excellent in chemical resistance and weather resistance.

The sound absorbing material of the present invention absorbs sound by utilizing the film vibration of the thin film 14 made of such a material. for that reason,
In order to obtain good sound absorption characteristics, the film thickness of the thin film 14 is preferably about 4 to 25 μm.

The sound absorbing material 10 of the illustrated example is constructed by sandwiching such a thin film 14 between Al expanded metals 12 and preferably press-bonding both of them together. There is no particular limitation on the method of pressure-bonding the both, and various methods such as a method using a press and a method using a roller can be applied. Also, the pressurizing pressure is not particularly limited, but usually 500 to 1000 kgf / cm
It is about ² .

In this way, the thin film 14 and the Al expanded metal 12 are entirely pressure-bonded to each other, whereby the sound absorbing material 10 is excellent in mechanical strength as well as having a favorable sound absorbing property, with a low risk of breaking the thin film. be able to.

Further, by adopting a configuration in which the entire surface is pressure-bonded, it is possible to cut and use it in a desired shape after manufacturing, and it is possible to widen the application range.

The sound absorbing material according to the first aspect of the present invention is composed of the thin film 14 and Al.
The expanded metal 12 is not limited to being entirely pressure-bonded. For example, the two may be laminated, then press-cut into a desired shape, and the periphery may be sealed.

FIG. 3 shows a schematic front view of the second embodiment of the sound absorbing material of the present invention, and FIG. 4 shows a sectional view schematically showing a sectional view taken along the line IV-IV.

The sound absorbing material 10 according to the first aspect of the present invention described above is basically
The sound absorbing material 30 according to the second embodiment of the present invention shown in FIGS. 3 and 4 has a structure in which the thin film 14 is sandwiched between the Al expanded metals 12 and is made of a resin mesh 3.
The thin film 14 is sandwiched by 2 and both are adhered by the double-sided tape 34. Here, since the thin film 14 is the same as the sound absorbing material 10 of the above-described first aspect, the description thereof will be omitted.

In the second aspect of the present invention, the resin net-like body 3 is thus formed.
By forming the sound absorbing material 30 with the thin film 2 and the thin film 14, it is possible to completely eliminate the obstacle caused by the radio wave shield.

The reticulate body 32 is a reticulated body made of various synthetic and natural resins, and the composition thereof is not particularly limited, but the weather resistance,
From the viewpoint of heat resistance, self-extinguishing with little deterioration with time, and excellent chemical resistance, it is preferable to use an ethylene-based resin, particularly an ethylene-fluoride-based resin.

The aperture ratio of such a mesh 32 is not particularly limited,
In order to obtain a good sound absorbing effect, it is preferable that the aperture ratio is 50% or more so that the film vibration can be sufficiently exhibited. The thickness of the mesh 32 is not particularly limited, but is usually 0.4.
It is about 2 mm.

The sound absorbing material 30 according to the second aspect of the present invention is formed by bonding the mesh body 32 and the thin film 14 with the double-sided tape 34 as in the illustrated example, or with various adhesives.

The applicable double-sided tape or adhesive is not particularly limited, but a material excellent in weather resistance is preferable.

When the double-sided tape 32 is used as the bonding means, the bonding area is preferably about 10% of the opening area of the mesh body 32.

Since the sound absorbing material 30 according to the second aspect of the present invention as described above has relatively low rigidity and is not as good in retaining self-shape as the sound absorbing material 10 described above, it is actually applied as a sound absorbing material for various applications. At this time, as shown in FIG. 5, it is preferable to provide an opening in a part of the casing 36 made of, for example, polycarbonate, and apply a certain amount of tension to the opening to equalize it.

The casing 36 is not limited to being made of polycarbonate, and various types of materials can be applied. However, the use of polycarbonate does not hinder the scenery,
Further, it is more preferable in that it does not cause radio interference.

The sound absorbing body of the present invention is a sound absorbing body including an air layer, a porous sound absorbing material layer, and an air layer and a porous sound absorbing material layer on the downstream side in the sound traveling direction of the sound absorbing material 10 or 30. It has a layer. In FIG. 6a, a sound absorbing body 20a having an air layer 22 as a sound absorbing layer of the above-mentioned sound absorbing material 10 is shown in FIG.
Similarly to the figure, the sound absorbing body 20 having the porous sound absorbing material layer 24
6b shows a sound absorbing body 20c having both of them. In addition, the arrow in the figure indicates the traveling direction of the sound.

By providing the air layer 22 behind the sound absorbing material of the present invention, the sound energy is converted into heat energy by the film vibration of the thin film 14, and the sound absorption coefficient can be improved, and a good sound absorbing body can be obtained. be able to.

The thickness of the air layer 22 is not particularly limited and may be appropriately determined according to the intended sound absorption characteristic, but is usually 50.
It is about 150 mm.

As the porous sound-absorbing material 24 arranged as the sound-absorbing layer of the sound-absorbing material 10 of the present invention, all the porous materials conventionally used as the sound-absorbing material such as glass wool and various kinds of metal fiber nonwoven fabrics can be applied.

By providing the porous sound absorbing material layer 24 behind the sound absorbing material of the present invention, it is possible to add a loss to the thin film 14 and improve the sound absorbing coefficient centered on the resonance frequency, and up to a high frequency from a low frequency. The sound absorption characteristics can be favorably influenced.

Since the sound absorption characteristics of the sound absorbing material change depending on the openings of the expanded metal or mesh, the thickness of the air layer 22, the density of the porous material, etc., the thickness of the porous sound absorbing material layer 24 is particularly There is no limitation, and it may be appropriately determined according to the installation location, environment, and the desired sound absorption characteristics.

Further, in the present invention, the porous sound absorbing material layer 24 may be arranged in parallel to the sound absorbing material 10 or may be arranged vertically.

When both the air layer 22 and the porous sound absorbing layer 24 are provided as the sound absorbing layers of the sound absorbing material 10, the order (with respect to the sound traveling direction) is not particularly limited. Also, the material,
The thickness and the like are as described above.

<Examples> Hereinafter, the present invention will be described in more detail with reference to specific examples of the present invention.

[Example 1] In order to investigate the characteristics of the sound absorbing material of the present invention, the center distance in the single eye direction is 7 mm, the center distance in the long eye direction is 14 mm, the plate thickness is 0.4 mm, and the center distance in the single eye direction is 14 mm, the long eye direction. Center distance of 2
Two pieces of 12 Al expanded metal 8 mm in thickness and 2.0 mm in thickness sandwiching a thin film 14 (made of PTFE) of 6 μm in thickness
000kgf / cm ² by rolling, the first thickness of 0.6mm
A sound absorbing material 10 shown in the drawings and FIG. 2 was produced.

Sound absorber 1-A (Example of the present invention) Air layer 2 having a thickness of 100 mm as the sound absorbing layer of the sound absorber 10
2 was provided to produce the sound absorber 20a shown in FIG. 6a.

Sound Absorber 1-B (Example of the Invention) As the sound absorbing layer of the sound absorbing material 10, a glass wool porous sound absorbing material layer 24 having a density of 32 kg / m ³ and a thickness of 25 mm is provided, and the sound absorbing body 20b shown in FIG. 6b is provided. It was made.

Sound Absorber 1-C (Example of the Present Invention) As the sound absorbing layer of the sound absorbing body 10, an air layer 2 having a thickness of 75 mm
2 and a porous sound-absorbing material layer 24 similar to the sound-absorbing body 1-B provided behind the sound-absorbing body 2c shown in FIG. 6c.
Was produced.

Sound Absorber 1-D (Comparative Example) A thin film (made of PTFE) having a thickness of 6 μm is spread on the frame body,
A sound absorbing body was produced by providing an air layer of 100 mm behind it.

Sound Absorber 1-E (Comparative Example) A sound absorber was manufactured using a glass wool porous sound absorber having a density of 32 kg / m ³ and a thickness of 25 mm.

Each sound absorbing material is a test piece having an area of 100 mmφ.

Using such sound absorbers 1-A to 1-E, normal incident sound absorption measurement was performed.

FIG. 7 shows each sound absorption characteristic curve.

As shown in FIG. 7, the sound absorbing body 1-A which is an example of the present invention.
1-C are sound absorbers 1-D and 1 which are conventional sound absorbers.
Has better sound absorption characteristics than -E. In particular, the sound absorbing body 1-C having both the air layer 22 and the porous sound absorbing material layer 24 as the sound absorbing layer has good characteristics. Also, thickness 6
Sound absorber 1 consisting of a μm thin film (made of PTFE) and an air layer
-D hardly absorbs sound.

The sound absorbers 1-A and 1-B according to the present invention were substantially transparent and did not obstruct the visual field.

Example 2 As shown in FIG. 8, the porous sound absorbing material layer 24 of the sound absorbing layer.
The total length of the sound absorbing layer is 100 in the same manner as in the sound absorbing body 1-C of Example 1 except that the sound absorbing material 10 is arranged vertically.
A sound absorber 2-A having a thickness of mm and a sound absorber 2-B having a total length of the sound absorbing layer of 80 mm were produced.

The normal incident sound absorption of each of the obtained sound absorbing materials was measured.

FIG. 9 shows each sound absorption characteristic curve.

As shown in FIG. 9, when the porous sound absorbing material 24 is arranged parallel to the sound traveling direction, a sound absorbing characteristic different from that arranged vertically (the sound absorbing body 1-C of Example 1) is obtained. be able to. Further, it is possible to obtain a sound absorbing body having different sound absorbing characteristics depending on the length of the sound absorbing layer.

[Example 3] Center distance in the single eye direction 7 mm, center distance in the long eye direction 14 mm,
Two 1mm thick reticulate bodies 32 (made of PTFE) with a thickness of 6μ
The thin film 14 of m (made of PTFE) was sandwiched and the two were adhered with a double-sided tape to fabricate the sound absorbing material 30 of the second aspect of the present invention shown in FIGS. 3 and 4.

Sound Absorber 3-A (Example of the Present Invention) An air layer 22 having a thickness of 100 mm was provided as the sound absorbing layer of the sound absorbing material 30 to manufacture a sound absorbing body similar to the sound absorbing body 20a shown in FIG. 6a.

Sound Absorber 3-B (Example of the Present Invention) As the sound absorbing layer of the sound absorbing material 10, a glass wool porous sound absorbing material layer 24 having a density of 32 kg / m ³ and a thickness of 25 mm is provided, and a sound absorbing body 20b shown in FIG. 6b is provided. A similar sound absorber was produced.

Using such sound absorbers 3-A and 3-B, normal incidence sound absorption measurement was performed.

FIG. 10 shows each sound absorption characteristic curve. The first
In FIG. 0, as a comparative example, the sound absorber 1-E of Example 1 described above is used.
The sound absorption characteristics of are also noted.

As shown in FIG. 10, the example of the present invention is
It can be seen that it has good sound absorption characteristics. Also, the sound absorber 3
-A and 3-B did not block radio waves at all.

[Example 4] Similar to the sound absorbing material 10 of Example 1, three types of sound absorbing materials were produced.

The Al expanded metal 12 used had a plate thickness of 0.
4 mm, center distance in single direction 3 mm, center distance in long direction 4 mm (sound absorbing material 4-A), center distance in single direction 7 mm, center distance in long direction 14 mm
(Sound-absorbing material 4-B) and the center distance in the single direction is 14 mm and the center distance in the long direction is 30 mm
It was changed to (Sound absorbing material 4-C).

Using the measurement system shown in FIG. 11, the radio wave passage rate (radio wave shielding effect) was measured for each of the obtained sound absorbing materials.

Results are shown in FIG.

The calculation was carried out by the following formula.

V _O : Transmission level with sample V _S : Transmission level without sample From the results shown in FIG. 12, it can be seen that the larger the aperture of Al expanded metal 12 is, the more the radio wave is transmitted. It can be seen that it passes well without being shielded.

In general, if the radio wave shielding effect is 8 db or less, it does not cause a television image interference. Therefore, it is understood that the sound absorbing material of the present invention does not cause a radio wave interference in any of the above examples.

[Example 5] The same experiment as in each of Examples 1, 2, 3 and 4 was conducted using a thin film 14 of vinylidene cyanide having a thickness of 6 µm. Good results have been obtained.

From the above results, the effect of the present invention is clear.

<Effects of the Invention> As described in detail above, the sound absorbing material of the present invention and the sound absorbing body of the present invention using the same have better sound absorbing properties than the conventional sound absorbing material made of a porous material. Moreover, the sound absorption characteristics do not deteriorate with time.

In addition, since it has good radio wave passage properties, it does not cause various types of radio wave interference.

Further, in addition to the above-mentioned characteristics, since it can be made substantially transparent, it does not obstruct the landscape even when applied to a sound absorbing material for a highway.

Further, according to the method for manufacturing a sound absorbing material of the present invention, it is possible to manufacture a sound absorbing material having such excellent characteristics satisfactorily at low cost and with high production efficiency.

[Brief description of drawings]

FIG. 1 is a schematic plan view of an embodiment of the sound absorbing material according to the first aspect of the present invention. FIG. 2 is a sectional view taken along line II-II of the sound absorbing material shown in FIG. FIG. 3 is a schematic plan view of an example of the sound absorbing material according to the second aspect of the present invention. FIG. 4 is a sectional view taken along line IV-IV of the sound absorbing material shown in FIG. FIG. 5 is a schematic perspective view showing an application example of the sound absorbing material shown in FIG. 6a, 6b, 6c and 8 are schematic sectional views of an embodiment of the sound absorbing body according to the present invention. FIG. 7, FIG. 9 and FIG. 10 are graphs showing the sound absorption characteristics of the sound absorbing body. FIG. 11 is a schematic diagram of a measurement system of the radio wave shield effect. FIG. 12 is a graph showing the radio wave shielding effect of the sound absorbing material. Explanation of symbols 10, 30 ... Sound absorbing material, 12 ... Aluminum expanded metal, 14 ... Thin film, 20a, 20b, 20c ... Sound absorbing body, 22 ... Air layer, 24 ... Porous sound absorbing material, 32 ... Net, 34 ... Double-sided tape, 36 ... Housing

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location B29L 28:00 4F

Claims (6)

[Claims] 1. A sound absorbing material, which is a laminate of an aluminum expanded metal and an ethylene fluoride thin film and / or a polyvinylidene thin film. 2. A sound absorbing material, which is a laminate of a resin mesh and an ethylene fluoride thin film and / or a polyvinylidene thin film. 3. The sound absorbing material according to claim 1, wherein the film thickness of the ethylene fluoride thin film and / or the polyvinylidene thin film is 4 to 25 μm. 4. At least one ethylene fluoride thin film and / or polyvinylidene thin film is laminated on an aluminum expanded metal, and an aluminum expanded metal is laminated thereon, and then the laminated body is pressurized to A method for producing a sound absorbing material, which comprises press-bonding an aluminum expanded metal and the ethylene fluoride thin film and / or the polyvinylidene thin film. 5. A resin net-like body is laminated with at least one ethylene fluoride thin film and / or a polyvinylidene thin film, and a resin net-like body is laminated on the thin film. A method for producing a sound-absorbing material, characterized in that at least a part of a net-like material and an ethylene fluoride thin film and / or a polyvinylidene thin film are bonded with a double-sided tape and / or an adhesive. 6. A sound absorbing layer comprising an air layer and / or a porous sound absorbing material layer is further provided on the downstream side of the sound absorbing material according to claim 1 in the traveling direction of sound to be shielded. And sound absorber.