JP2010014888A - Sound-absorbing structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin and light sound-absorbing structure in which sound-absorbing capability is excellent in a middle to high-frequency range where sensitivity of a human ear is high. <P>SOLUTION: The sound-absorbing structure includes: composite film sound-absorbing material placed in a sound source side and including a plate body which has a plurality of apertures, and a thin film placed on the plate body; and a porous sound-absorbing material placed adjacent to the composite film absorbing material. The thin film is 2 to 50 μm in thickness, and 1×10<SP>6</SP>to 5×10<SP>9</SP>Pa in elasticity. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present disclosure relates to a sound absorbing structure, and more particularly, to a sound absorbing structure in which a sheet-like composite film sound absorbing material and a porous sound absorbing material are combined.

  As a sound absorbing material used for the sound absorbing structure, generally, a plate-like sound absorbing material such as a perforated plate, or a porous sound absorbing material using a foam material or a fiber material is used. A plate-like sound absorbing material such as a perforated plate uses a sound absorbing mechanism based on a resonance phenomenon, so that, for example, by appropriately designing the size, shape, distance from the wall (back air layer) of the hole, etc. Although it is possible to select a resonance frequency range suitable for the application, the frequency range where sound can be absorbed is narrow. On the other hand, the porous sound-absorbing material utilizes the viscous resistance of air on the material surface and is generally excellent in sound-absorbing properties in a high frequency range.

  In general, the frequency and sound pressure level (audible range) of a sound that can be heard by humans range from 20 Hz to 20 kHz and approximately 0 dB to 120 dB, respectively, but the sensuous magnitude of sound depends on the frequency. In the international standard ISO226: 2003, an isosensitive curve (equal loudness curve) is standardized. According to this, the sensitivity of the human ear peaks at 3000 to 4000 Hz, and the sensitivity of the sound in the range of 2000 to 6000 Hz before and after that is higher than the sound in other frequency ranges. This means that the human ear can hear sound in this frequency range even with weak energy (sound pressure). Therefore, the industrial significance of a material capable of effectively absorbing sound in such a wide frequency range (2000 to 6000 Hz) is great.

  Some attempts have been made so far to expand the frequency range in which the sound absorbing structure can be absorbed.

  In Patent Document 1, “a membrane vibration sound absorbing material formed by laminating at least one plate-like body having a large number of openings and at least one thin film is disposed on the sound source side, and behind this film vibration sound absorbing material. A soft fiber porous sound absorbing material or an open cell type elastic foam sound absorbing material is disposed on the side, and a sound insulation plate is disposed on the side opposite to the sound source. The sound absorbing action is based on membrane vibrations caused by vibrating air particles, and vibrates. Sound absorption effect based on frictional resistance through which air particles pass through the pores, and sound absorption effect on the membrane vibration sound absorption material by the soft fiber porous sound absorption material or the open cell elastic foam sound absorption material acting as a spring There is described a “sound-absorbing structure characterized by the purpose of sound absorption in a low frequency band of 100 Hz to 300 Hz as well as a middle and high frequency band of a frequency of 400 Hz or more due to a synergistic effect”.

  Patent Document 2 states that “a film-like or thin plate-like material C is sandwiched between a mesh structure A and a mesh structure B that transmit sound waves, and these are partially fixed to each other to form a multilayer structure. Furthermore, there is described a “composite sound absorbing structure characterized in that the network structure B of the composite structure and the porous sound absorbing material E are intimately combined”.

JP 2000-250561 A JP 2006-153926 A

  However, it is very difficult to achieve high sound absorption performance over a wide frequency range as described above. For example, since the sound absorption characteristic of the porous sound absorbing material is suitable for a high frequency range (about 4000 Hz or higher), it is necessary to increase the thickness of the sound absorbing material in order to improve the sound absorbing performance in the middle frequency range or lower. However, when the thickness is increased in such a manner, the volume of the sound absorbing material increases or the weight increases, which restricts the installation of the sound absorbing structure using such a sound absorbing material. In addition, the method of combining the porous sound absorbing material with another film material or sound absorbing material is effective in improving the sound absorbing performance in the middle frequency range by changing the sound absorbing profile of the porous sound absorbing material. In many cases, the sound absorption performance in the high frequency range, which was originally excellent, is deteriorated.

  In view of the above, the present disclosure provides a thin and lightweight sound absorbing structure having excellent sound absorbing performance in a medium frequency region to a high frequency region where the sensitivity of the human ear is high.

According to the present disclosure, there is provided a composite film sound-absorbing material disposed on the sound source side, and a plate-shaped body having a plurality of openings and a thin film disposed on the plate-shaped body, and disposed adjacent to the composite film sound-absorbing material. A sound absorbing structure having a porous sound absorbing material, wherein the thin film has a thickness of 2 to 50 μm and an elastic modulus of 1 × 10 ^{6 to} 5 × 10 ⁹ Pa.

  According to the present disclosure, it is possible to obtain a thin and lightweight sound absorbing structure that exhibits excellent sound absorbing characteristics in the middle to high frequency range of 2000 to 6000 Hz.

  The above description should not be construed as disclosing all embodiments of the present disclosure and all advantages related to the present disclosure.

  Hereinafter, the present disclosure will be described in more detail for the purpose of illustrating representative embodiments of the present disclosure, but the present disclosure is not limited to these embodiments.

  A sound absorbing structure according to an embodiment of the present disclosure is shown in FIGS. 1 and 2 in a cross-sectional view and a top view, respectively. The sound absorbing structure 10 of the present disclosure includes a composite film sound absorbing material 20 having a plate-like body 21 having a plurality of openings 23 and a thin film 22 disposed on the plate-like body 21, and adjacent to the composite film sound absorbing material 20. The porous sound absorbing material 30 is arranged. By combining the composite film sound absorbing material and the porous sound absorbing material in this way, the sound absorbing structure of the present disclosure is thin and lightweight, and has excellent sound absorbing performance in a wide frequency range from the middle frequency range to the high frequency range. Demonstrate.

  The composite film sound absorbing material used in the present disclosure is a sheet-like or film-like sound absorbing material, and is a structure in which a plate-like body having a plurality of openings and a thin film are combined. The plate-like body is in contact with the thin film at least partially, preferably substantially entirely, with respect to the effective sound absorption region. The plate-like body and the thin film may be laminated using, for example, heat, an adhesive, or the like, and their peripheral portions may be partially fixed by rivets, stitching, or the like. Alternatively, if the thin film is relatively flexible and exhibits some degree of tack, the plate may simply be crimped to the thin film. Moreover, when the thin film and the plate-like body are made of the same material, for example, an integrally molded composite film sound-absorbing material may be produced by embossing a resin film having a certain thickness.

  Further, the thin film may be sandwiched between two plate-like bodies having a plurality of openings, and both surfaces of one plate-like body may be covered with two thin films. Further, a plurality of plate-like bodies and a plurality of thin films may be alternately arranged and overlapped. Further, when a plurality of plate-like bodies are used, those having the same opening size (opening ratio per unit area) may be used, or different ones may be used. Depending on the target sound absorption frequency range, the type of porous sound absorbing material to be combined, and the like, use of a plurality of plate-like bodies having different aperture ratios per unit area may provide better sound absorption characteristics.

  As described above, the sound absorption characteristic of the composite film sound absorbing material in which the plate-like body having a plurality of openings and the thin film are combined is wider than that of the thin film alone. The sound absorbing effect by the thin film is due to the vibrational air particles vibrating the film and converting the energy of the sound into film vibration. Therefore, in a single thin film, the resonance frequency, that is, the sound absorption frequency is limited by its dimensions (area and thickness), mass, material, and the like. While not being bound by any theory, the composite film sound absorbing material of the present disclosure is based on the sound absorbing action of the plate itself and the propagation of vibration from the thin film to the plate at the contact portion between the plate and the thin film. It is considered to exhibit a wide range of sound absorption characteristics.

  Alternatively, the thin film may be attached to a plate-like body having a plurality of openings by weakening the tension of the thin film, that is, slackening the thin film. This may be effective for widening the sound absorption characteristics by diversifying the resonance frequency, or for frequency shifting the sound absorption characteristics.

  In the present disclosure, as a plate-like body having a plurality of openings, for example, a resin or metal mesh, net, perforated plate, or any other material and shape can be used. For example, a resin mesh or net is preferably used in applications where flexibility is required for the sound absorbing structure, such as when installed on a complicated shape surface, or applications where a lightweight sound absorbing structure is desired.

  The aperture ratio of the opening of the plate-like body is desirably 40% or more, or 60% or more, and on the other hand, desirably 90% or less, or 80% or less. The aperture ratio is expressed as a percentage obtained by dividing the area of the plate-like body by the area of the opening provided in the plate-like body with respect to the effective sound absorption region. By setting the aperture ratio in the above-described range, it is possible to effectively realize a wide range of sound absorption characteristics without impairing the sound absorption performance originally possessed by the thin film.

  The shape of the opening of the plate-like body may be any shape such as a square, a rectangle, a hexagon, and a circle. A plurality of openings may be arranged in a lattice shape, that is, a grid shape. When the openings are hexagonal, they may be arranged in a so-called honeycomb shape. In addition, the sizes of the individual openings may be the same or different from each other. For example, the resonance frequency can be reduced by making the vicinity of the center of the effective sound absorption region a large lattice and decreasing the size of the lattice toward the periphery. It may be diversified. Regarding the grid-shaped opening, the length of one side of the unit grid is preferably 1 mm or more, or 2 mm or more, while it is preferably 5 mm or less, or 4 mm or less. By making the length of one side of the unit grid within the above-mentioned range, when the composite film sound absorbing material is combined with the porous sound absorbing material to make the sound absorbing structure, the sound absorbing characteristics of the sound absorbing structure are obtained in the target sound absorbing frequency range. Can be adapted. An example of a suitable plate-like body having a grid-shaped opening is not limited to the following, but a resin-made or metal net or mesh provided with an orthogonal grid having a length of one side of the unit grid of 1 mm to 2 mm. Can be mentioned.

  The thickness of the plate-like body having a plurality of openings is preferably 10 μm or more, or 100 μm or more, while it is preferably 1 mm or less, or 0.75 mm or less. If it is 10 μm or more, sufficient strength and durability for practical use can be secured, and it is sufficient for realizing a wide range of sound absorption frequency. If it is 1 mm or less, the thickness applied to the sound absorbing structure is kept to a minimum. be able to.

The thin film that can be used in the present disclosure is a sheet having an elastic modulus at room temperature of about 1 × 10 ⁶ Pa or more and about 5 × 10 ⁹ Pa or less, preferably about 5 × 10 ⁶ Pa or more and about 5 × 10 ⁸ Pa or less. It is a film. As the thin film having the above elastic modulus, it is desirable to use a polymer resin film. Among polymer resin films, relatively flexible materials such as urethane elastomers, styrene elastomers, olefin elastomers, acrylic elastomers, amide elastomers, vinyl chloride elastomers, and silicone elastomer films, and these films The laminate is preferred. When a composite film sound absorbing material using such a material as a thin film is combined with a porous sound absorbing material, the sound absorbing characteristics in the medium frequency range (about 1000 Hz to about 4000 Hz) are greatly improved compared to the porous sound absorbing material alone, In the high frequency range (about 4000 Hz to about 6000 Hz), the deterioration of the sound absorption characteristic can be kept to a minimum, or such a high frequency range sound absorption characteristic can be maintained and further improved. Without being bound by any theory, when the above-mentioned material is selected and used as a thin film, not only a single resonance frequency but also a wider frequency range causes bending deformation of the material. It is considered that the sound absorption frequency is widened with respect to the sound absorption effect based on the above.

  The thickness of the thin film used for the composite film sound-absorbing material is preferably 2 μm or more, or 5 μm or more, while it is preferably 50 μm or less, or 25 μm or less. If the thickness of the thin film is 2 μm or more, sufficient strength and durability can be secured for practical use. If the thickness of the thin film is 50 μm or less, reflection of sound waves by the thin film is suppressed and effective for the entire sound absorbing structure. Sound absorption can be achieved. In general, when a thin film becomes thicker and its weight increases, sound reflection becomes more dominant than sound absorption due to resonance vibration of the film. In that case, since the sound wave is reflected on the surface of the composite film sound absorbing material before reaching the porous sound absorbing material included in the sound absorbing structure, the porous sound absorbing material does not function as the sound absorbing material. Further, as the thickness of the thin film is thinner, the rigidity of the thin film is lowered, and the material is likely to be bent and deformed in a wider frequency range. From these viewpoints, the thin film is preferably thin as long as sufficient strength can be secured.

  The porous sound-absorbing material used in the present disclosure is a material having continuous pores or voids inside the material. The sound-absorbing action of the porous sound-absorbing material is due to the fact that sound waves, that is, vibrating air particles, receive frictional resistance or viscous resistance when passing through pores or voids. In general, the sound absorption characteristics of the porous sound absorbing material are excellent in a high frequency range (about 4000 Hz or more).

  Examples of the porous sound-absorbing material that can be used in the present disclosure include woven fabrics, knitted fabrics or nonwoven fabrics made from fibers such as glass wool, rock wool, and polyester, or open-cell foam materials such as polyurethane foam.

Among such porous sound-absorbing materials, microfibers and short fibers that are lighter than other porous sound-absorbing materials of the same thickness and have excellent sound-absorbing properties due to a large surface area per unit volume or unit mass The nonwoven fabric comprised from these is preferable. Such a nonwoven fabric maintains or even improves sound absorption characteristics in a high frequency range (5000 Hz to 6000 Hz) when combined with a composite film sound absorbing material, particularly a composite film sound absorbing material including a flexible polymer resin film. However, it may be particularly effective. The density of such a nonwoven fabric is desirably 5 mg / cm ³ or more, or 10 mg / cm ³ or more, while desirably 200 mg / cm ³ or less, or 100 mg / cm ³ or less. When the density is less than 5 mg / cm ³ , it is difficult to sufficiently bring out the performance of the porous sound-absorbing material. When the density exceeds 200 mg / cm ³ , it deviates from the original purpose of a thin and lightweight sound-absorbing structure. Come. Further, the thickness of the nonwoven fabric to be used is desirably about 1 mm or more and about 20 mm or less. By setting it as such a range, sufficient sound-absorbing performance can be obtained about a medium frequency range-a high frequency range, making the thickness or bulkiness of a sound absorption structure very small. The thickness of the nonwoven fabric when actually used by being incorporated in a sound absorbing structure may vary. In general, the sound absorption characteristics of porous sound-absorbing materials tend to decrease as the thickness decreases.However, after considering the level of sound absorption characteristics required and the restrictions on installation space, the sound-absorbing characteristics are further compressed and thinned as necessary. May be used.

  From the viewpoints of processability, availability of raw materials, environmental characteristics, and the like, materials constituting the nonwoven fabric composed of such microfibers and short fibers are polyolefins, acrylic resins (for example, modacrylic), polyesters, and their Desirably it is selected from the group consisting of mixtures. In order to achieve both lightness and bulkiness, the fiber diameter of the microfiber is preferably about 0.1 μm or more and about 10 μm or less, and the fiber diameter of the short fiber is preferably about 10 μm or more and about 50 μm or less. As an example of the nonwoven fabric composed of the microfiber and the short fiber as described above, the product number TAI-2047 of trade name Thinsulate (registered trademark) nonwoven fabric (manufactured by 3M) manufactured by the melt blown method is not limited to the following. TAI-1047 etc. are mentioned, The fiber diameter of the microfiber contained in these nonwoven fabrics is about 1-4 micrometers, and the fiber diameter of a short fiber is about 20-30 micrometers.

  The sound absorbing structure of the present disclosure is formed by disposing the composite film sound absorbing material adjacent to the porous sound absorbing material so that the above-described composite film sound absorbing material is disposed on the sound source side. When using a composite film sound-absorbing material provided with a plate-like body on one side of the thin film, the porous sound-absorbing material may be adjacent to the surface on which the plate-like body is provided, or may be adjacent to the surface on which the plate-like body is not provided. . It is also possible to sandwich the porous sound absorbing material using two composite film sound absorbing materials. The composite sound-absorbing material and the porous sound-absorbing material may be simply in contact with each other without using fixing means, and their peripheral portions may be partially fixed by rivets, stitching, or the like, or Other members, for example, a frame or a case, may be encapsulated so as to come into contact with each other in the state where the effective sound absorption region is exposed.

  In the sound-absorbing structure of the present disclosure, the composite film sound-absorbing material thin film and / or the plate-like material is composited so as to at least partially physically contact the material constituting the porous sound-absorbing material, for example, the nonwoven fabric fibers. The membrane sound absorbing material and the porous sound absorbing material are disposed adjacent to each other. Without being bound by any theory, in such a sound absorbing structure, the vibration of the composite film sound absorbing material that has absorbed sound waves propagates to the porous sound absorbing material through the contact portion, and as a result, the porous sound absorbing material It is thought that a sound absorbing action different from the sound absorbing action obtained by the composite film sound absorbing material alone or the porous sound absorbing material alone is caused by the material being deformed and the absorbed sound energy being dissipated. Yes.

  The sound absorbing structure according to the present disclosure obtained in this manner is a composite film sound absorbing material and a porous sound absorbing material that have been used in the past while exhibiting excellent sound absorbing performance in a wide frequency range of about 2000 to 6000 Hz that humans perceive sensitively. Since it can be made very thin in comparison, it is particularly useful for applications where the installation space of the sound absorbing structure is restricted, for example, for electronic devices such as laptop computers, sound equipment and sound absorbing applications such as acoustic equipment and precision machines.

  Hereinafter, representative examples will be described in detail, but it will be apparent to those skilled in the art that the following embodiments can be modified and changed within the scope of the claims of the present application.

The following three types were used as plate-like bodies having a plurality of openings.
Grid A Grid net made by UV curing acrylic resin Grid B Commercially available polypropylene resin grid net (pitch 1.3 mm × 1.3 mm, net line width 250 μm, aperture ratio 65%, thickness 400 μm)
Grid C A commercially available stainless steel grid metal mesh (pitch 1.6 mm × 1.6 mm, mesh line width 200 μm, aperture ratio 77%, thickness 400 μm)

Production of Grid A Grid A was produced as follows. A mixed solution of 10 parts of Shigomi (registered trademark) UV-1700B manufactured by Nippon Synthetic Chemical Industry Co., Ltd., 5 parts of hydroxyethyl acrylate, and 0.2 part of Darocur 1173 of Ciba Japan was prepared. The mixture of the photocurable resin was sandwiched between the release treatment surfaces of two PET films subjected to silicone release treatment, and the thickness was adjusted to 500 μm with a knife coater. On top of this, a mask through which light passes through a grid-shaped opening having a pitch of 1.7 mm × 1.7 mm was covered. The line width of the lattice opening was 350 μm. In this state, using a high-pressure mercury lamp (H-type bulb, 120 W / cm) manufactured by Fusion System Corporation, the resin was cured by placing it on a conveyor at a speed of 30 m / min. At this time, the light amount of UVA measured with a light meter UV POWER PUCK (registered trademark) II manufactured by EIT was 90 mJ / cm ² . Next, this cured product was washed with methyl ethyl ketone to remove the uncured portion, and then dried, and the pitch was 1.7 mm × 1.7 mm, the line width was 350 μm, the aperture ratio was 63%, and the thickness was 450 μm. Grid A was obtained.

The following polyurethane film, PET film, and SIS film were used as the thin film of this example, and aluminum foil was used as the thin film of the comparative example.
Polyurethane film (thickness 10 μm, elastic modulus 4.5 × 10 ⁷ Pa)
PET film (Thickness 5, ⁹ , 16 μm, elastic modulus 4.1 × 10 ⁹ Pa)
SIS film (thickness 12 μm, elastic modulus 2.8 × 10 ⁷ Pa)
Aluminum foil (thickness 12 μm, elastic modulus 6.8 × 10 ¹⁰ Pa)

  A composite film sound-absorbing material was produced by combining the above-described grid and thin film. When the thin film was a polyurethane film or a SIS film, the grid was bonded to the thin film as it was. When the thin film was a PET film and an Al foil, a small amount of spray adhesive was applied to the grid and attached to the thin film.

The following three types of porous sound absorbing materials were used.
Thinsulate (registered trademark) (manufactured by 3M, product number TAI-2047, density when measured with a thickness of 10 mm is 20 mg / cm ³ )
Thinsulate (registered trademark) (manufactured by 3M, product number TAI-1047, the density when measured with a thickness of 10 mm is 10 mg / cm ³ )
Polyurethane foam (manufactured by Strider, product number F-2 (25 mg / m ³ ), thickness 10 mm)

Measurement of sound absorption coefficient The sound absorption coefficient was measured according to a normal incidence sound absorption coefficient measurement method (2 microphone method) (ASTM E 1050).

Examples 1-11
The composite film sound-absorbing material and porous sound-absorbing material shown in Table 1 were punched out to 29 mmφ and overlapped so that the grid of the composite film sound-absorbing material faced outward to form a sample of the sound-absorbing structure for measuring the sound absorption coefficient. A sample was placed inside the impedance tube so that the composite film sound absorbing material was on the sound source side and the porous sound absorbing material was on the rigid wall side. The thickness at the time of measurement was adjusted to the value shown in Table 1, and the sound absorption coefficient was measured in the frequency range of 500 to 6400 Hz.

Comparative Examples 1-4
The sound absorption rate was measured by the same method as in Examples 1 to 11 except that only the porous sound absorbing material was used without using the composite film sound absorbing material.

Comparative Example 5
The sound absorption rate was measured in the same manner as in Examples 1 to 11 except that only the polyurethane film was overlaid on TAI-2047.

Comparative Example 6
The sound absorption coefficient was measured in the same manner as in Examples 1 to 11 except that a composite film sound absorbing material using Al foil as a thin film was combined with polyurethane foam.

  FIG. 3 is a graph showing the measurement results of Example 1 (grid + thin film), Comparative Example 1 (no composite film sound absorbing material) and Comparative Example 5 (only a thin film).

  4, Example 2 (the thickness of the porous sound absorbing material is compressed to half (5 mm) of Example 1), Comparative Example 1 (no composite film sound absorbing material, 10 mm thick porous sound absorbing material) and Comparative Example 2 (composite film) The measurement results of the absence of the sound absorbing material and the compression of the thickness of the porous sound absorbing material to 5 mm are shown in a graph.

  FIG. 5 is a graph showing the measurement results of Example 3 (the density of the porous sound-absorbing material is half that of Example 1 and a thickness of 5 mm) and Comparative Example 3 (using the same porous sound-absorbing material as Example 3 and no composite film sound-absorbing material). Show.

  In FIG. 6, the measurement result of Examples 4-6 (grid AC) and the comparative example 1 (no composite film sound-absorbing material) is shown with a graph.

  FIG. 7 shows Comparative Example 1 (composite film) in addition to Examples 7 to 9 (using PET having a different thickness as a thin film) and Example 10 (using SIS as a thin film) using TAI-2047 as a porous sound absorbing material. The measurement result of “without sound absorbing material” is shown in a graph.

  In FIG. 8, in addition to Example 11 (using SIS as a thin film) and Comparative Example 6 (using Al foil as a thin film) using urethane foam as the porous sound absorbing material, Comparative Example 4 (without composite film sound absorbing material) The measurement results are shown in a graph.

  In FIG. 9, the plots of Example 10, Example 11, Comparative Example 1, and Comparative Example 4 are excerpted for the purpose of showing that the sound absorption characteristics differ depending on the type of the porous sound absorbing material.

It is sectional drawing of the sound-absorbing structure by one embodiment of this indication. It is a top view of a sound absorption structure by one embodiment of this indication. 6 is a graph showing measurement results of Example 1, Comparative Example 1 and Comparative Example 5. 3 is a graph showing measurement results of Example 2, Comparative Example 1 and Comparative Example 2. 10 is a graph showing measurement results of Example 3 and Comparative Example 3. It is a graph which shows the measurement result of Examples 4-6 and the comparative example 1. FIG. It is a graph which shows the measurement result of Examples 7-9, Example 10, and the comparative example 1. FIG. 10 is a graph showing measurement results of Example 11, Comparative Example 4 and Comparative Example 6. It is a graph which shows that a sound absorption characteristic changes with kinds of porous sound-absorbing material.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Sound-absorbing structure 20 Composite film sound-absorbing material 21 Plate-shaped body 22 Thin film 23 Opening 30 Porous sound-absorbing material

Claims (7)

A composite film sound-absorbing material having a plate-like body having a plurality of openings and a thin film arranged on the plate-like body, and arranged on the sound source side,
A sound absorbing structure having a porous sound absorbing material disposed adjacent to the composite film sound absorbing material,
The thin film is a sound absorbing structure having a thickness of 2 to 50 μm and an elastic modulus of 1 × 10 ^{6 to} 5 × 10 ⁹ Pa.   The sound absorbing structure according to claim 1, wherein an aperture ratio of the plate of the composite film sound absorbing material is 40% to 90%.   The plate-like body of the composite film sound-absorbing material has a grid-like opening, the thickness of the plate-like body is 10 μm to 1 mm, and the length of one side of the unit grid of the plate-like body is 1 mm to 5 mm. The sound-absorbing structure according to any one of claims 1 and 2.   The sound-absorbing structure according to any one of claims 1 to 3, wherein the thin film is a polymer resin film.   The polymer resin film is selected from the group consisting of urethane elastomers, styrene elastomers, olefin elastomers, acrylic elastomers, amide elastomers, vinyl chloride elastomers, silicone elastomer films, and laminates of these films. The sound-absorbing structure according to claim 4. The porous sound-absorbing material, a nonwoven fabric composed of micro fibers and short fibers, the thickness of the nonwoven fabric is 1 to 20 mm, density of ^{5mg / cm 3 ~200mg / cm 3} , claim 5 The sound absorbing structure according to any one of the above.   The material constituting the nonwoven fabric is selected from the group consisting of polyolefin, acrylic resin, polyester and mixtures thereof, the fiber diameter of the microfiber is 0.1 to 10 μm, and the fiber diameter of the short fiber is 10 to 50 μm The sound absorbing structure according to claim 6.

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