JPH0683365A - Film vibrating sound absorber - Google Patents

Abstract

PURPOSE:To secure not only excellent sound absorption characteristics, workability, and strength, but also transparency and dust protection by holding a thin resin film between plate type bodies which have many openings. CONSTITUTION:The film vibrating sound absorber (sound absorber) 70 when using metal plates as the plate type bodies having many openings is constituted by holding the thin resin film 16 between two punching metal plates which differ in opening ratio, i.e., punching metal 72 having small openings 72a and punching metal 74 having large openings 74a. Namely, the thin film resin film which has a continuous surface or plural rupture parts is hold by plate bodies which have many openings and shape self-holding property such as punching metal and expand metal, preferably, plate bodies which differ in opening rate, and then superior sound absorbing characteristics are obtained by adding sound absorbing operation by the plate bodies having many openings in addition to the film vibration of the thin resin film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has not only sound absorption characteristics but also light weight and excellent workability, and if necessary, see-through through this sound absorbing material, dust-proof property and dust-free property. The present invention also relates to a membrane vibration-absorbing material that can be secured, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Various sound absorbing materials are used for soundproofing in various places such as airfields, highways and their surroundings, music halls, gymnasiums, construction sites, tunnels, and clean rooms.

Such sound absorbing materials are all made of porous material such as glass fiber, rock wool, soft porous material such as felt such as sponge, porous sintered plate, metal fiber board, porous molded plate such as metal foam plate, etc. The sound absorbing material has a general concept that it is a porous material. These sound absorbing materials have merits and demerits in various points such as sound absorbing characteristics, weather resistance, price, processing method, etc., and materials suitable for them are used depending on the application.

By the way, in recent years, the use of sound absorbing materials has been diversified, and various characteristics other than the sound absorbing characteristics have been required. In one of them, in the place where the sound absorbing material is placed,
There is a view through the sound-absorbing material, that is, see-through.

For example, on an expressway, soundproof walls made of sound absorbing material are arranged as side walls on both sides of the road in order to prevent noise pollution to nearby residents. Polycarbonate was used as a soundproof wall of a highway because of its good sound insulation, but the sound insulation wall made of polycarbonate has a high internal reflection sound. In addition, such a conventional soundproof wall completely blocks the visibility outside the road, so that the passenger cannot see the outside scenery, and it also gives the driver a feeling of pressure. In addition to the sound absorbing characteristics, the appearance of a sound absorbing material having visibility is desired.

Further, as noise in factories and laboratories, there is noise originating from various machine tools, measuring machines, pumps, boilers, generators, and the like. These noise sources are operated while being surrounded by a sound absorbing material made of a porous material such as glass fiber as necessary.However, since the conventional sound absorbing material does not have visibility, the operating condition of the machine is Since it cannot be confirmed through the sound absorbing material, the appearance of a sound absorbing material having good visibility is also desired here.

On the other hand, in a clean room or the like, it is absolutely necessary to prevent the generation and intrusion of dust. However,
Since the conventional sound absorbing material is a porous material, its application to a clean room is inappropriate.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and secure not only good sound absorbing characteristics, workability and strength, but also visibility through the sound absorbing material. It is also possible to provide a membrane vibration-absorbing material that can be suitably used in a clean room or the like without any problems, and can also ensure dustproofness and dustproofness as needed, and a method for producing the same. .

[0009]

In order to achieve the above-mentioned object, the present inventor has conducted extensive studies and accomplished the present invention by obtaining the following findings.

As described above, as the material of the sound absorbing material which is generally used at present, soft porous materials such as glass fiber and rock wool; porous materials such as porous sintered plate, metal fiber plate and metal foam plate Formed plate material; perforated plate material such as punching metal; and the like are used. It is difficult to secure visibility when examining these sound absorbing materials.

On the other hand, film vibration of a thin film such as a vinyl sheet,
That is, it is known that sound is slightly absorbed by causing vibration on a smooth surface. However, the sound absorbing effect obtained by applying the vibration of the smooth surface is very low, and the maximum sound absorbing coefficient is about 0.3 to 0.4, so that it has not been put to practical use.

[0012] Here, the present inventor has studied the sound absorption due to the film vibration of the thin film in detail, and has obtained the following findings. Conventionally, as a large number of sound absorbing materials, there is known a sound absorbing material 54 in which a glass fiber 50 is covered with a thin film 52 such as a vinyl sheet as a surface protective material as shown in FIG. The sound absorbing material 54 as described above is generally used in combination with the sound insulating material 56 (rigid body), but the sound absorbing characteristics differ depending on the state of the thin film 52.

In the state shown in FIG. 1 (a), that is, in the state where the thin film 52 is loosely stretched, the characteristics of the sound absorbing material 54 are mainly determined by the density and thickness of the glass fiber 50. By controlling the thickness, rigidity, etc. of the thin film 52, it is possible to obtain a sound absorbing material that exhibits good sound absorbing characteristics over a wide frequency range. However, as shown in FIG. 1B, in the case where the area of the thin film 52 is small and the glass fiber 50 is covered with the sound absorbing material 54 while the thin film 52 has a tension, The characteristics of the sound absorbing material 54 are determined by the tension and thickness of the thin film 52, regardless of the density and thickness of the glass fiber 50.

That is, the sound absorbing material 5 shown in FIG.
In the state where the thin film 52 has flexibility as in No. 4, the sound wave G
When the film hits the thin film 52, the sound absorption coefficient is determined by the characteristics of the glass fiber 50 in most cases. In contrast,
When the thin film 52 is in a tensioned state as shown in FIG. 1B, most of the sound waves G are reflected by the thin film 52, and the sound absorption characteristics are substantially determined by the thin film 52. Here, the sound absorption characteristic of the thin film 52 is determined by the resonance frequency f. The resonance frequency f is shown by the following formula. f = [C ² · (ρ m / E) ^1/2 ] /1.8t In the above formula, C is the speed of sound, ρ m is the volume density of the thin film 52, t is the thickness of the thin film 52, and E is the thin film 52. The Young's modulus of each is shown.

As is clear from the above equation, the volume density ρm
When is constant, the resonance frequency f is greatly affected by the Young's modulus E of the thin film 52, that is, the tension and the thickness t of the thin film 52.

Here, such a thin film does not have self-shape retention. Therefore, in order to make the thin film usable as a sound absorbing material, it is necessary to hold the thin film 52 by some holding member while maintaining an appropriate tension as described above. The present inventor has studied a method capable of suitably holding a thin film in a state where appropriate tension and visibility are secured, and as a result, a plate-shaped body having a large number of openings such as expanded metal, punching metal, and wire mesh has Alternatively, by sandwiching a thin film having a plurality of fractured parts, the thin film can be held while ensuring tension and visibility, and in addition to the sound absorbing action due to the above-mentioned membrane vibration, the sound absorbing action by the plate-shaped body is added, which is extremely excellent. The inventors have found that a sound absorbing special product can be developed and have completed the present invention. That is, a first aspect of the membrane vibration absorbing material of the present invention provides a membrane vibration absorbing material characterized in that a resin thin film is sandwiched between plate-shaped bodies having a large number of openings. The second aspect of the membrane vibration sound absorbing material of the present invention is
(EN) Provided is a membrane vibration sound absorbing material, which comprises a porous body and a laminated body in which a resin thin film is sandwiched by plate-like bodies having a large number of openings.

Further, in the above-mentioned membrane vibration sound absorbing material of the present invention, it is preferable that the aperture ratios of the plate-like members sandwiching the resin thin film are different from each other.

Further, in the above-mentioned membrane vibration sound absorbing material of the present invention, it is preferable that the plate-like body is any of expanded metal, punching metal and wire mesh.

In the membrane vibration sound absorbing material of the present invention, it is preferable that the plate-shaped body is made of aluminum and / or iron.

Further, when the membrane vibrating sound absorbing material of the present invention is used for a soundproof wall such as a highway, it is preferable that the resin thin film is transparent.

When the membrane vibration-absorbing material of the present invention is used as a soundproof wall in a clean room or the like, it is preferable that the resin thin film is a continuous surface.

Further, when the membrane vibration-absorbing material of the present invention is used for a soundproof wall other than a clean room, it is preferable that the resin thin film has a broken portion.

The membrane vibration-absorbing material of the present invention as described above can have various forms depending on the application. For example, by using a resin thin film having a continuous surface over the entire surface, that is, by using a resin thin film having no broken portion at all, it is possible to secure not only sound absorbing characteristics but also extremely excellent dustproofness and dustlessness, and it is possible to secure a clean room or the like. It can be used for various purposes. In addition, by combining a porous material on the backside (on the side opposite to the sound source with respect to the sound absorbing material), it is possible to obtain better sound absorbing characteristics while ensuring dustproofness and dustproofness in the clean room.

On the other hand, by using a transparent resin thin film, good visibility can be secured, and visibility is required such as soundproof walls for airports and highways and soundproofing members for machines inside factories. It can be preferably used for various purposes. Moreover, by forming a break in the resin thin film, it is possible to express a more excellent sound absorption characteristic by the film vibration of the break, and in the state where the visibility is secured, an extremely excellent sound absorption characteristic is obtained. It can be particularly suitably used for applications requiring both visibility and excellent sound absorption characteristics such as highways and factories. In this case, a transparent sound insulating material may be used together.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION The membrane vibration absorbing material of the present invention will be described in detail below. FIG. 2 shows a schematic view of an example of the membrane vibration sound absorbing material of the present invention. In addition, in FIG. 2, (a) is a partially cutaway plan view of an example of the membrane vibration absorbing material of the present invention, and (b) is a sectional view taken along the line bb.

A membrane vibration sound absorbing material (hereinafter referred to as a sound absorbing material) 70 shown in FIG. 2 is a plate-like body (hereinafter, referred to as a sound absorbing material) having a large number of openings.
As a plate-shaped body), a so-called punching metal formed by forming a large number of openings in a metal plate is used, and two punching metals having different opening ratios, that is, a punching metal 72 having a small opening 72a are used. Big opening 7
The resin thin film 16 is sandwiched by the punching metal 74 having 4a.

The sound absorbing agent of the present invention has such a structure, that is, a plate-like body having a large number of openings and having a self-shape-retaining property, preferably a plate-like body having a different opening ratio, such as punching metal and expanded metal. By having a structure in which a resin thin film having a continuous surface or having a plurality of fractured portions is sandwiched, in addition to the film vibration of the resin thin film, the sound absorbing action of the plate-shaped body having a large number of openings is taken into consideration, which is extremely excellent. It develops sound absorption characteristics. Moreover, in the illustrated example, the resin thin film 16 has a simple structure in which it is sandwiched between the two punching metals 72 and 74, and exhibits extremely excellent sound absorbing characteristics.

The sound absorbing action of the sound absorbing material of the present invention will be described with reference to FIG. As described above, the resin thin film 16 that has no tension and has an appropriate degree of slack can receive a sound wave and vibrate to exhibit good sound absorbing characteristics. Here, in order to obtain good sound absorption characteristics by utilizing the film vibration of the resin thin film 16, it is necessary that the resin thin film 16 be sufficiently vibrable with respect to sound waves. A fixed area is required. On the other hand, as will be described later, the resin thin film 16 capable of obtaining good sound absorption characteristics has a thickness of 4 to
It is a thin film of about 50 μm and has an area necessary for sound absorption,
The resin thin film 16 that exhibits good sound absorption characteristics has a problem in strength. Further, the resin thin film itself does not have shape retention.

On the other hand, the sound absorbing material 70 of the present invention has a structure in which the resin thin film is sandwiched by plate-like members (having different aperture ratios), punching metals 72 and 74 in the illustrated example, so that the resin thin film 16 vibrates. The resin thin film 16 is prevented from being damaged. That is, in the opening portion of the punching metal 72, only one surface of the resin thin film 16 is pressed by the punching metal 74, so that this portion can freely vibrate with respect to sound waves. On the other hand, even if it is a vibrating part, one surface is pressed by the punching metal 72 having a small opening, so that the resin thin film is protected by the other punching metal 74 even when a force is applied from the outside. And will not break.

The film vibration and the sound absorbing action of the plate-like body (having a large number of openings) will be described in more detail below by the punching metal 72 and the punching metal 74 as shown in FIG. 2B. When the sound wave G is incident on the sandwiched resin thin film 16, the resin thin film 16 vibrates due to the compression action of the sound wave (vibrating air) that strikes the surface of the resin thin film 16 to exhibit a sound absorbing action (hereinafter referred to as sound absorbing action a). . In addition, the sound wave G incident on the resin thin film 16
Flows along the surface of the resin thin film 16, the sound wave G
The sound absorbing action is expressed by the viscous action of the flow (hereinafter referred to as the sound absorbing action b). Further, when the resin thin film 16 vibrates as in the sound absorbing action a described above, the punching metal 72 and the punching metal 74 sandwiching the resin thin film 16 are held.
At the same time, it absorbs vibration and sound energy to exert a sound absorbing action (hereinafter referred to as a sound absorbing action c). The sound absorbing material of the present invention can exhibit extremely excellent sound absorbing characteristics due to the synergistic effect of the above sound absorbing functions a to c when the resin thin film 16 is a continuous surface having no breakage portion.

Here, the resin thin film 16 is not a continuous surface,
In the case of having a plurality of breaks such as notches formed regularly or irregularly, the effects of the sound absorbing effects b and c are almost eliminated, and the sound absorbing action by the film vibration of the broken parts (hereinafter, sound absorbing action d and Is exhibited, and a so-called Helmholtz resonance structure can be formed together with the above-described sound absorbing action a to exhibit extremely excellent sound absorbing characteristics. In the case where the sound absorbing agent of the present invention has a broken portion in the resin thin film 16, the sound absorbing characteristic is almost governed by the sound absorbing effects a and d. Therefore, the resin thin film 16 does not have to be combined with a plate-like body such as punching metal. Good sound absorption characteristics can be obtained even when combined with a soft porous material such as glass wool or rock wool.

In the sound absorbing material of the present invention as described above, the plate-shaped body is not limited to the punching metal shown in the drawing, and has a large number of openings such as a wire mesh, expanded metal, resin net or perforated plate. There are no particular limitations on various plate-like bodies that can maintain their own shapes. Further, the resin thin film may be sandwiched by different materials such as punching metal and expanded metal, punching metal and wire mesh, and the like. In addition,
For the sake of convenience, the following description will be made with a punching metal 7 as a plate-shaped body.
An example using Nos. 2 and 74 will be described as a typical example, but basically the same applies to the case where a wire net or expanded metal is used unless otherwise specified.

In the sound absorbing material 70 of the present invention, the aperture ratio of the punching metals 72 and 74 is not particularly limited,
In order to obtain good sound absorption characteristics, it is preferable to set the aperture ratio to about 30 to 80%. The shape of the opening 72a and the like is not particularly limited, and may be round, triangular or the like other than the quadrangle shown in the figure.

Here, as a preferred mode, the sound absorbing material 70 of the illustrated example has different opening ratios between the punching metals 72 and 74. With such a configuration, the above-described sound absorbing effects a to c can be exhibited well, and more excellent sound absorbing characteristics can be obtained. In the present invention, punching metal having different aperture ratios means that the area of one opening (72a or 74a) of each punching metal is different. The difference in the aperture ratio is not particularly limited as long as the openings 72a and 74a of the punching metals 72 and 74 that sandwich the resin thin film 16 do not overlap with each other and can be appropriately displaced.

The sound absorbing material of the present invention is not limited to sandwiching the resin thin film by punching metals having different aperture ratios as in the illustrated example, and the resin thin film 16 is sandwiched by punching metals having the same aperture ratio. It may be. In this case, the holes of the punching metal holding the resin thin film 16 are not overlapped with each other (that is, the openings are shifted) and the resin thin film 16 is held by the punching metal. c can be well expressed, and good sound absorption characteristics can be obtained.

The plate thickness of the punching metal to be used is not particularly limited, but in consideration of sound absorption characteristics, handleability, workability, etc., productivity in the mode of pressure bonding described later, etc.
Those having a thickness of about 3 to 1 mm are preferably used. For the same reason, when the expanded metal is used as the plate, it is usually 0.4 mm to 5 mm, and when the wire mesh is used as the plate, the wire diameter is 0.3 mm to 2 mm. Each is preferably used.

In the sound absorbing material of the present invention, the material of the plate-like body such as punching metal is not particularly limited, and various metals such as aluminum, iron and copper, alloys such as stainless steel and various resins are used. It is possible. In particular, aluminum and its alloys are preferable in terms of workability, weather resistance, and lightness, and in the case of a plate-like body to be pressure-bonded to be described later, in terms of mutual adhesion and adhesion with the resin thin film 16. Used for. Further, iron and its alloys are also preferably used in terms of sound absorption characteristics and the like.

The sound absorbing material 70 of the present invention has a structure in which the resin thin film 16 is sandwiched between the punching metal 74 and the punching metal 72. The sound absorbing material 70 of the present invention, which has the above-described configuration, realizes a sound absorbing material that utilizes the film vibration of the resin thin film, has excellent strength and processability, and has line-of-sight and dust-proof properties as necessary. Is.
Moreover, the illustrated example also has a punching metal 72 and 7
It is a simple structure in which the resin thin film is sandwiched by 4.

As the resin thin film 16 used in the present invention, various known resin thin films such as a vinyl chloride thin film, a polyethylene thin film, a polypropylene thin film, an ethylene fluoride thin film, a polyvinylidene thin film and an acrylic thin film can be used. Any of these is applicable, but in terms of sound absorption characteristics, weather resistance, durability, etc., an ethylene fluoride thin film and a polyvinylidene thin film are particularly preferably applied.

As the ethylene fluoride resin used for the ethylene fluoride thin film, various known resins are exemplified, but tetrafluoroethylene (PTFE), tetrafluoroethylene-6.
Fluoropropylene copolymer, tetrafluoroethylene / polyethylene copolymer (ETFE), trifluoroethylene chloride (PCT
FE) and the like are preferably exemplified. These fluoroethylene-based resins are nonflammable and have excellent chemical resistance, weather resistance, and heat resistance.

As the polyvinylidene-based resin used as the polyvinylidene-based thin film, various known resins are exemplified, but vinylidene difluoride (PVDF), vinylidene cyanide and the like are preferably exemplified. These vinylidene resins are excellent in chemical resistance and weather resistance.

The thickness of such a resin thin film 16 is as follows.
Although not particularly limited, it is preferably about 4 to 50 μm, preferably 6 to 1 in order to obtain a suitable membrane vibration and realize good sound absorption characteristics.
It is preferable that the thickness is about 0 μm.

As described above, the sound absorbing material 70 of the present invention uses the punching metal having the openings 18 to form the resin thin film 16.
It has a configuration of sandwiching. Therefore, the resin thin film 16
By selecting a transparent material, it is possible to secure the see-through through the sound absorbing material 70, and it is possible to secure sound absorption such as sound barriers for highways, sound insulating materials for machines installed in factories and laboratories. It becomes possible to use it particularly suitably for the application in which the opposite side observation is desired through the material.

The resin thin film 16 used in the sound absorbing material 70 of the present invention is not limited to the transparent one, and it goes without saying that it may be opaque. The resin thin film 16 may be colored, and the punching metal or the like may be colored in accordance with the resin thin film 16.

The resin thin film 16 may be a continuous surface, that is, one that does not have a broken portion at all, or one that has a broken portion. When the resin thin film 16 is a continuous surface, that is, one having no fractured part, the above-mentioned sound absorbing actions a to c are used. On the other hand, when the resin thin film 16 having a fractured part is used, the sound absorbing action a and Due to d, excellent sound absorbing characteristics can be exhibited.

For example, the resin thin film 1 of the sound absorbing material 70 of the present invention.
By using a thin film having no breakage as 6,
It can be suitably used in applications where dustproofness and dustproofness are strongly required, such as a clean room of an LSI factory. With the advance of technology in recent years, the need for a clean room is increasing in LSIs, chemical factories, laboratories and the like. Since various sound sources such as various manufacturing machines, analysis / measurement equipment, etc. are installed inside the clean room, it is necessary to prevent noise in terms of work environment, etc., but conventional sound absorbing materials use porous materials. Therefore, it is difficult to prevent the generation and intrusion of dust, and this alone cannot be used as a sound absorbing material for a clean room.

On the other hand, since the sound absorbing material 70 of the present invention is a sound absorbing material that utilizes the film vibration of the resin thin film without using a porous material, there is no fear of dust generation. Moreover, the resin thin film 16
If there is no breakage part, it is possible to prevent the intrusion of dust from the outside and use the conventional porous sound absorbing material (behind the sound source) in combination while ensuring dustproofness and dustlessness. It is also possible to obtain better sound absorption characteristics. The membrane vibration sound absorbing material (another aspect of the present invention) in which this porous material is combined will be described in detail later. Therefore, the sound-absorbing material 70 of the present invention, particularly the sound-absorbing material 70 of the present invention which does not have a broken portion in the resin thin film 16, is a sound-absorbing material for use in applications requiring extremely high dustproofness and dustlessness such as in a clean room. It is extremely useful as a material.

On the other hand, by forming a broken portion such as a cut in the resin thin film 16, it is possible to exhibit a more excellent sound absorbing characteristic. As described above, the sound absorbing material 70 of the present invention is a sound absorbing material that utilizes the film vibration of the resin thin film 16. However, by forming a ruptured portion in the resin thin film 16, at the time of sound absorption, this ruptured portion is formed together with the resin thin film 16. The film can vibrate to exhibit excellent sound absorbing characteristics (the above-mentioned sound absorbing action d).
Further, the visibility is not impaired by the formation of the fractured portion. Therefore, the mode in which the resin thin film 16 has the fractured portion can be particularly suitably used for applications requiring both visibility and sound absorption characteristics such as highways and factories.

When the resin thin film 16 is to be formed with breaks, the breaks are regularly formed in conformity with the openings of the punching metal 74 having a large opening or the punching metal 72 having a small opening, or are irregular. There is no limitation on what is formed, and there is no limitation on the number of breaks. Further, the size and shape may be set to an arbitrary size so as not to impair the strength of the resin thin film 16.

The method of manufacturing the sound absorbing material 70 of the present invention is not particularly limited, and for example, a laminated body of the punching metals 72 and 74 and the resin thin film 16 is formed, and the peripheral portion and any portion are variously formed. It may be fixed with a member or an adhesive, or the periphery may be pressed with a frame or the like.

FIG. 3 is a schematic plan view of another example of the sound absorbing material of the present invention, FIG. 4 is a schematic sectional view taken along the line AA, and FIG.
Line schematic sectional views are respectively shown. Sound absorbing material 10 in the illustrated example
Is formed by the expanded metal 12 having a large opening and the expanded metal 14 having a small opening.
6 is sandwiched between the expanded metal 12 and the resin thin film 1
6 and the expanded metal 14 are pressure-bonded to each other.

The expanded metal basically has a shape as shown in FIG. 6, and a large number of cuts are made in a thin metal plate, and the cuts are pulled in a substantially right-angled direction to form an opening 18. It is a mesh. The expanded metal is a twisted portion in which the cut cross section of the metal thin plate is twisted by a tensile force and is displaced not only in the direction perpendicular to the plane of the metal thin plate but also in the parallel direction, the diagonal direction, etc. In the mode in which the laminated body sandwiched by the expanded metal is pressure-bonded, the resin thin film 16 and the expanded metal are entangled with each other and can be well adhered.

In such an expanded metal, the size of the opening 18 and the like differ depending on the degree of processing such as the above-mentioned notch and pulling. The degree of processing of the expanded metal applied to the present invention is not particularly limited, and may be appropriately determined according to the adhesion between the expanded metal and another member, the desired sound absorbing characteristics, and the like. In such a crimping mode, an expanded metal having a large opening is usually 1 mm to 5 mm, and an expanded metal having a small opening is usually 0.4 mm to 1.5 mm. When a wire net is used as the plate,
A wire net having a large opening has a wire diameter of 1 mm to 2 mm, and a wire net having a small opening has a wire diameter of 0.3 mm to 1 mm.

Here, in the mode of pressure bonding like the sound absorbing material 10 of the illustrated example, a better sound absorbing coefficient is exhibited when the opening ratios of the two expanded metals 12 and 14 sandwiching the resin thin film 16 are different. You can In particular, the larger the opening ratio of the expanded metal 12 having the large opening 18 (the larger the opening 18 is), the better the vibration of the resin thin film 16 with respect to the sound wave and the better sound absorbing characteristics can be obtained.

In the sound absorbing material 10, the difference in the opening ratio between the expanded metal 12 and the expanded metal 14 (the difference in the size of the opening) is not particularly limited and may be appropriately selected according to the use of the sound absorbing material 10. In terms of sound absorption characteristics, visibility described later, damage prevention of the resin thin film 16, and the like, the opening 18 of the expanded metal 12 is normally provided with the expanded metal 1.
It is about 1 to 50 times as large as the opening 18 of No. 4 and the size of the opening of the expanded metal may be selected in consideration of the frequency of sound absorption.

As a method of manufacturing the sound absorbing material 10 having a structure in which the resin thin film 16 is sandwiched by the pressure bonding as described above, various laminated body manufacturing methods can be applied, but preferably, the resin thin film 16 is expanded metal 12. A laminated body sandwiched between the expanded metal 14 and the expanded metal 14 is produced, and the laminated body is continuously pressed by a roll or the like to be pressure-bonded.
A method of producing a plate-shaped laminate as shown in (FIG. 5) can be mentioned.

First, the resin thin film 16 is sandwiched between the expanded metal 12 and the expanded metal 14 to produce a laminated body, and then the laminated body is pressure bonded using a press, a roll or the like to form a plate-shaped laminated body. By using such pressure bonding, as shown in FIG. 5, which is a cross-sectional view along the expanded metal 12, the expandable metal 12 having a large opening penetrates the small expanded metal 14 due to the malleability of the metal. The respective materials are preferably in close contact with each other, and can be cut into an arbitrary shape after processing or processed into a desired shape. In particular, by using an Al-based expanded metal formed of Al or an Al-based alloy as the expanded metal, more preferably, by using an annealed Al-based expanded metal, the strong adhesion of each material can be obtained. It is possible to obtain a sound absorbing material excellent in strength, workability, and the like, particularly in a mode by pressure bonding.

The pressure at which the sound absorbing material 10 is pressure-bonded and manufactured in this manner is not particularly limited, but is preferably 300 to 300 from the viewpoint that each material can be suitably adhered.
It is preferably about 2000 kg / cm ² . Further, the pressure may not be entirely applied, but may be partially applied, and an adhesive or the like may be used as an auxiliary as necessary. In addition, when the fractured portion is formed on the resin thin film 16, the resin thin film 16 may be preliminarily cut at a desired position and provided with a scratch or the like in advance.

When using such a sound absorbing material of the present invention, although not particularly limited, it has a plate-like body with a low aperture ratio, that is, a small opening so that vibration of the resin thin film 16 due to sound waves can be favorably generated. It is preferable to turn the plate-shaped body toward the sound source.

Another mode of the membrane vibration sound absorbing material of the present invention is such a sound absorbing material 70 or 10, that is, a plate-shaped body such as punching metal or expanded metal, preferably a plate-shaped body having a different aperture ratio, and having a continuous surface. Or a layered body in which a resin thin film having a broken portion is sandwiched, and a conventionally known porous sound absorbing material such as glass fiber or rock wool is further combined. With such a structure, it is possible to realize a sound absorbing material having extremely good sound absorbing characteristics, which has both the characteristics of the sound absorbing material of the present invention and the porous material.

[0061]

EXAMPLES Hereinafter, the (membrane vibration) sound absorbing material of the present invention will be described in more detail with reference to specific examples of the present invention. Example 1 A square punching metal having an opening of 12 × 12 mm (aperture ratio 56%) and a square punching metal having an opening of 10 × 10 mm (aperture ratio 64%) had a breakage portion having a thickness of 9 μm. A transparent PTFE thin film was sandwiched between them to produce the sound absorbing material of the present invention in the mode shown in FIG. 2 (mode in which a resin thin film was simply sandwiched between plate-like bodies). Using such a sound-absorbing material, removing the back air layer of 80 mm, JIS
The vertical incident sound absorption coefficient was measured based on 1405-1963. As the sound absorbing material, a square punching metal having an opening of 10 × 10 mm was arranged on the sound source side. The results are shown in Fig. 7.
As shown in FIG. 7, it can be seen that the sound absorbing material of the present invention has good sound absorbing characteristics over a wide frequency range.

[Embodiment 2] Square punching metal having an opening of 12 × 12 mm (opening ratio 56%) and expanded metal made of Al having a plate thickness of 1 mm (center distance in the short direction of the opening is 5 mm, in the long direction) A flat thin plate made by rolling a center distance of 10 mm) into a flat shape and sandwiching a transparent PTFE thin film having a thickness of 6 μm and not having a broken portion, and a resin thin film as shown in FIG. The sound-absorbing material of the present invention in a state of being sandwiched between the bodies was produced. Using such a sound absorbing material,
Taking the back air layer of 0 and 80mm, JIS 14
The vertical incident sound absorption coefficient was measured based on 05-1963. As the sound absorbing material, square punching metal having expanded metal was arranged on the sound source side. The results are shown in Fig. 8. As shown in FIG. 8, it can be seen that the sound absorbing material of the present invention has good sound absorbing characteristics over a wide frequency range. In FIG. 8, a shows the result of the back air layer of 50 mm, b shows the result of the back air layer of 60 mm, and c shows the result of the back air layer of 80 mm.

Example 3 The following materials were prepared as materials for producing the sound absorbing material of the present invention in a crimped form as shown in FIG. a. Expanded metal S made of Al with a plate thickness of 1 mm (center distance in the short direction of the opening is 5 mm, center distance in the long direction is 10 mm) b. Expanded metal L made of Al with a plate thickness of 2 mm (center distance in the short direction of the opening is 36 mm, center distance in the long direction is 76 m)
m) c. 10 μm-thick transparent PTFE thin film c d. Transparent PTFE thin film d having a break of 10 μm in thickness

Using each of the above materials, a laminate having a PTFE thin film sandwiched between Al expanded metals was prepared and
By pressure-bonding with kg / cm ² , various (membrane vibration) sound-absorbing materials shown below in the embodiment shown in FIG. 3 were produced. The materials used (produced laminate) are shown in Table 1 below.

80 mm using the produced sound absorbing material and an air layer of 80 mm or a glass fiber having an areal density of 32 kg / m ^3.
The sound absorption coefficient of the building material according to JIS A1409-1967 by the reverberation chamber method was measured in combination with the glass fiber layer (hereinafter referred to as GF layer). The produced sound absorbing material was measured with the expanded metal S having a small opening facing the sound source side. The measurement result of the sound absorption coefficient is shown in FIG. In addition, the presence or absence of the air layer and the glass fiber layer,
It is also shown in Table 1 with ○ (Yes) and × (No).

[0066]

As shown in FIG. 9, compared with the sound absorbing materials A and B in which the thin film c having no fractured part and the thin film d having a fractured part are sandwiched by expanded metals having the same aperture ratio, expanded metal having different aperture ratios. The sound absorbing materials C and D having the same thin film sandwiched therebetween exhibit a good sound absorption coefficient. Also,
The sound absorbing materials E and F using the GF layer instead of the air layers behind the sound absorbing materials C and D exhibit better sound absorbing characteristics.

[Embodiment 4] Instead of the expanded metal L of b, an expanded metal having a larger aperture ratio, that is, an expanded metal having a center distance of 50 mm in the short direction of the opening and a center distance of 100 mm in the long direction is used. Then, the membrane vibration sound absorbing material of the present invention was produced and the same experiment was conducted. As a result, it was possible to obtain more excellent sound absorption characteristics than the sound absorption characteristics shown in FIG. From the above results, the effect of the present invention is clear.

[0069]

As described above in detail, according to the present invention, not only good sound absorbing characteristics, workability and strength but also visibility through the sound absorbing material can be secured, and in a clean room or the like. In applications, it is possible to realize a sound absorbing material that can also secure dustproofness as needed,
It can be suitably used for various purposes.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining an influence of a thin film used as a sound absorbing material on sound absorbing characteristics.

FIG. 2A is a schematic plan view showing an example of the membrane vibration absorbing material of the present invention, and FIG. 2B is a sectional view taken along the line bb.

FIG. 3 is a schematic perspective view showing another example of the membrane vibration sound absorbing material of the present invention.

FIG. 4 is a schematic cross-sectional view taken along the line AA of the sound absorbing material shown in FIG.

5 is a schematic cross-sectional view of the sound absorbing material shown in FIG. 3 taken along the line BB.

FIG. 6 is a schematic perspective view of expanded metal.

FIG. 7 is a graph showing sound absorbing characteristics of an example of the membrane vibration sound absorbing material of the present invention.

FIG. 8 is a graph showing sound absorption characteristics of another example of the membrane vibration sound absorbing material of the present invention.

FIG. 9 is a graph showing sound absorption characteristics of another example of the membrane vibration sound absorbing material of the present invention.

[Explanation of symbols]

 10,70 Membrane vibration sound absorbing material 12 Expanded metal (large opening) 14 Expanded metal (small opening) 16,52 Resin thin film 18 Opening 72,74 Punching metal G Sound wave

Claims (8)

[Claims] 1. A membrane vibration sound absorbing material, characterized in that a resin thin film is sandwiched between plate-like members having a large number of openings. 2. A membrane vibration sound-absorbing material comprising: a laminate having a resin thin film sandwiched between plate-like bodies having a large number of openings; and a porous material. 3. The membrane vibration sound absorbing material according to claim 1, wherein the plate-shaped bodies sandwiching the resin thin film have different aperture ratios. 4. The plate-shaped body is any of expanded metal, punching metal and wire mesh.
A membrane vibration sound absorbing material according to any one of 1. 5. The membrane vibration sound absorbing material according to claim 1, wherein the plate-shaped body is made of aluminum and / or iron. 6. The membrane vibration absorbing material according to claim 1, wherein the resin thin film is transparent. 7. The resin thin film is a continuous surface.
A membrane vibration sound absorbing material according to any one of 1. 8. The membrane vibration sound absorbing material according to claim 1, wherein the resin thin film has a plurality of fractured portions.