Sound insulation material

Abstract

To provide a novel sound insulation material capable of improving sound insulation performance and realizing weight reduction.SOLUTION: A sound insulating material includes a first layer formed of a first porous body, and a second layer disposed to face the first layer via an air layer and formed of a second porous body.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to sound insulation. [Background technology]

[0002] Patent Document 1 discloses an insulator arranged in a dash panel of a vehicle. This insulator is made of olefin resin or rubber resin and is arranged between an engine room and a driver's cab. The insulator blocks the sound of the engine, which is a noise source. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-248833 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, with the electrification of vehicles, there is a demand for insulators with sound insulation performance different from that for vehicles equipped with conventional engines. It is desirable for such insulators to be able to improve the sound insulation performance against the driving noise generated by electric components such as motors. Furthermore, it is desirable for the insulators to be lightweight and contribute to reducing the weight of the entire vehicle.

[0005] An object of the present invention is to provide a novel sound-insulating material that can improve sound-insulating performance and achieve weight reduction. [Means for solving the problem]

[0006] A sound-proofing material according to one embodiment of the present disclosure comprises a first layer formed of a first porous body, and a second layer formed of a second porous body and arranged opposite the first layer with an air layer between them. Effect of the Invention

[0007] The present disclosure can provide a novel sound-insulating material that improves sound-insulating performance and achieves weight reduction. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing the use of sound-proofing material. [Diagram 2] FIG. [Diagram 3] FIG. 4 is an exploded perspective view showing a laminated structure of the sound-proofing material. [Figure 4] 1 is a cross-sectional view of a laminated structure of a sound-proofing material. [Diagram 5] Top view of the middle layer. [Figure 6] Graph showing the sound insulation performance of sound insulation materials. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.

[0010] 1, a sound-insulating material 1 according to an embodiment of the present disclosure is used as a sound-insulating material to be attached to a vehicle C. The sound-insulating material 1 is attached to a body panel that separates a noise source of the vehicle C from the passenger compartment, and prevents noise generated from the noise source from being transmitted to the passenger compartment.

[0011] The sound insulation material 1 of this embodiment is provided near the fender of a vehicle C to insulate road noise transmitted through the tires and driving noise in the engine room. The sound insulation material 1 is disposed inside the space formed between an exterior panel of the fender portion of the vehicle C and an outer panel forming a wheel house.

[0012] The sound-insulating material 1 is not limited to this, and may be any sound-insulating material arranged in a space between body panels constituting the vehicle C. For example, the sound-insulating material 1 may be arranged in a dash panel for separating an engine room from a passenger compartment of the vehicle C. The sound-insulating material 1 may also be arranged in the passenger compartment of the vehicle C.

[0013] 2, the sound-insulating material 1 includes a first layer 2, a second layer 4, and an intermediate layer 6 disposed between the first layer 2 and the second layer 4. The sound-insulating material 1 of this embodiment is formed to fit the shape of a body panel of a vehicle C (see FIG. 1). The direction in which the first layer 2, the second layer 4, and the intermediate layer 6 of the sound-insulating material 1 are laminated generally coincides with the front-rear direction of the vehicle C.

[0014] Next, the laminated structure of the sound insulation material 1 will be described with reference to Figures 3 to 6. As shown in Figure 3, the sound insulation material 1 of this embodiment has a three-layer structure in which a first layer 2, a second layer 4, and an intermediate layer 6, all of which have approximately the same thickness, are laminated. The first layer 2 and the second layer 4 are each bonded to the intermediate layer 6. As a result, the first layer 2, the second layer 4, and the intermediate layer 6 form an integrated sound insulation material 1.

[0015] The first layer 2 is in a sheet shape that extends in the X and Y directions and has a thickness h1 in the Z direction. The thickness h1 of the first layer 2 is formed to be about 10 mm.

[0016] The first layer 2 has an upper surface 21 and a lower surface 22 opposite to the upper surface 21. The upper surface 21 faces the intermediate layer 6.

[0017] The first layer 2 is formed of a first porous body. The first porous body is a foamed resin molding, and may be a porous body in the narrow sense, which is a material having a large number of fine pores in the base material, or may be a sponge or foam, which is a material in which bubbles are generated and air bubbles are mixed in the base material. The base material of the first porous body may be a thermoplastic resin or a thermosetting resin.

[0018] The first porous body may be a closed-cell foam in which the cells are not connected, but is not limited thereto, and may be a porous body in which the cells are connected or an open-cell foam.

[0019] In addition, with regard to the manufacturing method, the first porous body may be a resin porous body in which soluble components dispersed in a resin have been dissolved, a resin foam in which bubbles are generated from gas dissolved in the resin, or a resin foam in which bubbles are generated by thermal decomposition or chemical reaction of a foaming agent.

[0020] The first porous body of the present embodiment has an apparent density of approximately 50 kg / m 3 from 150kg / m 3 (JIS K 6767), elongation of 90% or more (JIS K 6767), 25% compressive stress of 200kPa or less (JIS K 6767), water absorption of 0.01g / cm 3 The first porous body is polyethylene (PE) having a non-breathable closed cell structure as specified below (JIS K 6767). However, the first porous body is not limited to this, and a thermoplastic resin or a thermosetting resin other than polyethylene can be selected.

[0021] The thermoplastic resin base material of the first porous body can be selected from general-purpose plastics such as polyvinyl chloride (PVC), polypropylene (PP), polyethylene (PE), polystyrene (PS), acrylonitrile butadiene styrene (ABS resin), acrylonitrile styrene (AS resin), polymethyl methacrylate (PMMA), polybutylene terephthalate (PBT), and polyethylene terephthalate (PET).

[0022] In particular, examples of thermoplastic resin substrates that have excellent impact resistance include amorphous plastics such as polyvinyl chloride (PVC), polymethyl methacrylate (PMMA), ABS (acrylonitrile butadiene styrene) resin, and polycarbonate (PC), as well as polyurethane-based thermoplastic elastomers (TPU), and olefin-based thermoplastic elastomers (TPO), etc.

[0023] As the thermosetting resin base material, for example, phenol resin, urea resin, melamine resin, alkyd unsaturated polyester, epoxy resin, thermosetting polyurethane resin, diallyl phthalate resin, silicone resin, and the like can be selected.

[0024] The second layer 4, like the first layer 2, is in a sheet shape that extends in the X and Y directions and has a thickness h2 in the Z direction. The second layer 4 in this embodiment has the same shape as the first layer 2, and the thickness h2 of the second layer 4 is formed to be about 10 mm, like the thickness h1 of the first layer 2.

[0025] The second layer 4 has an upper surface 41 and a lower surface 42 opposite the upper surface 41. The lower surface 42 faces the intermediate layer 6.

[0026] The second layer 4 is formed of a second porous body. The second porous body is a foamed resin molded body, and may be a porous body or a foamed body made of a thermoplastic resin or a thermosetting resin. The second porous body may also be a non-ventilated foamed resin molded body having a closed-cell structure. The second porous body may be molded of the same foamed resin as the first porous body, or may be molded of a different foamed resin.

[0027] The second porous body of the present embodiment has an apparent density of about 50 kg / m, similar to the first porous body. 3 from 150kg / m 3 (JIS K 6767), elongation of 90% or more (JIS K 6767), 25% compressive stress of 200kPa or less (JIS K 6767), water absorption of 0.01g / cm 3 It is polyethylene (PE) with a non-breathable closed cell structure as specified below (JIS K 6767).

[0028] The intermediate layer 6, like the first layer 2 and the second layer 4, is in the form of a sheet that extends in the X and Y directions and has a thickness h3 in the Z direction. The thickness h3 of the intermediate layer 6 in this embodiment is equal to or greater than the thickness h1 of the first layer 2 and the thickness h2 of the second layer 4, and is formed to be, for example, about 10 to 30 mm.

[0029] The intermediate layer 6 is formed of a third porous body. The third porous body is a foamed resin molded body, and may be a thermoplastic resin or a thermosetting resin. The third porous body may also be a non-permeable foamed resin molded body having a closed-cell structure. The third porous body may be molded of the same foamed resin as the first and second porous bodies, or may be molded of a different foamed resin.

[0030] The third porous body of the present embodiment has an apparent density of about 50 kg / m, similar to the first and second porous bodies. 3 from 150kg / m 3 (JIS K 6767), elongation of 90% or more (JIS K 6767), 25% compressive stress of 200kPa or less (JIS K 6767), water absorption of 0.01g / cm 3 It is polyethylene (PE) with a non-breathable closed cell structure as specified below (JIS K 6767).

[0031] 4, the intermediate layer 6 has an opening 61. The opening 61 is a through hole that penetrates the intermediate layer 6 in the thickness direction (arrow Z direction). The lower part of the opening 61 is closed by the upper surface 21 of the first layer 2. The upper part of the opening 61 is closed by the lower surface 42 of the second layer 4.

[0032] The opening 61 forms an air layer 62 between the first layer 2 and the second layer 4. The first layer 2 and the second layer 4 are disposed facing each other in the thickness direction (direction of arrow Z) via the air layer 62. This allows the sound insulation material 1 to form a hollow double-wall structure against sound transmitted along the stacking direction of the first layer 2, the second layer 4 and the intermediate layer 6 (direction of arrow Z).

[0033] For example, sound waves transmitted from the first layer 2 side are first partially reflected by the first layer 2, and then partially reflected as they are transmitted from the air layer 62 to the second layer 4. Similarly, sound waves transmitted from the second layer 4 side are reflected in two stages, by the second layer 4 and the first layer 2. Such attenuation of sound waves due to the double-wall structure with the air layer 62 sandwiched between them is called the double-wall effect. This double-wall effect makes it possible to improve the sound insulation performance of the sound-insulating material 1.

[0034] Moreover, the sound insulation material 1 can be made lighter by the volume of the openings 61 in the intermediate layer 6 than a solid sound insulation material having the same volume as the sound insulation material 1. Furthermore, the sound insulation material 1 can be made lighter by the first layer 2 and the second layer 4 being porous than a sound insulation material in which the first layer 2 and the second layer 4 are made of solid metal or resin. As a result, the sound insulation material 1 can obtain sound insulation performance due to the double-wall effect while being lighter in weight.

[0035] 5, the opening 61 in this embodiment has a square shape when viewed from above, but the opening 61 is not limited to this and may have a variety of shapes such as a circle or a polygon.

[0036] A plurality of openings 61 are provided and arranged regularly side by side. In this embodiment, as shown by the dashed line in Fig. 5, the intermediate layer 6 is defined as a square with each side measuring approximately 10 cm when viewed from above, and the opening 61 is disposed at the center of the square. Note that the size of the square defining the intermediate layer 6 can be changed as appropriate depending on the size of the sound-proofing material 1 and the mounting position on the vehicle C (see Fig. 1).

[0037] Next, the relationship between the aperture ratio R of the openings 61 and the sound insulation performance of the sound insulation material 1 will be described with reference to Fig. 6. Fig. 6 is a graph showing the relationship between the frequency of sound waves transmitted to the sound insulation material 1 and the transmission loss of the sound waves attenuated by the sound insulation material 1 for each of a plurality of aperture ratios R.

[0038] In the experiment, a sound insulation material without an opening 61, i.e., an aperture ratio R of 0% (comparative example), and four types of sound insulation materials 1 with aperture ratios R of 10% (example 1), 25% (example 2), 50% (example 3), and 75% (example 4) were prepared. The sound wave transmission loss in each frequency range of these five sound insulation materials was measured. The sound wave transmission loss is a general index for measuring sound insulation performance, and indicates the difference in sound pressure level between the sound incident on the sound insulation material 1 and the sound transmitted through the sound insulation material 1. The greater the difference in sound pressure level, i.e., the greater the transmission loss, the higher the sound insulation performance of the sound insulation material 1.

[0039] As shown in Fig. 6, the comparative example shows low transmission loss at frequencies around 6000 Hz. Focusing on the vicinity of 6000 Hz, Examples 1 to 4 show large transmission loss compared to the comparative example, regardless of the magnitude of the aperture ratio R. Furthermore, Examples 2 to 4 show large transmission loss compared to the comparative example in most of the frequency bands shown in Fig. 6.

[0040] For example, when the aperture ratio R is 10% or more, a higher transmission loss is exhibited in the frequency range of 5000Hz to 10000Hz than in the comparative example. When the aperture ratio R is 25% or more, a higher transmission loss is exhibited in the frequency range of 3150Hz to 10000Hz than in the comparative example.

[0041] In particular, while the transmission loss in the comparative example and Examples 1 and 2 increases with increasing frequency, Examples 3 and 4 show a significant increase in transmission loss in the low frequency band of 1600 Hz to 2000 Hz. Specifically, Example 3 shows a significant increase in transmission loss in the frequency band around 2000 Hz. Moreover, Example 4 shows a significant increase in transmission loss in the frequency band around 1600 Hz.

[0042] Furthermore, in Example 4, a uniquely high transmission loss is shown in the frequency band around 1600 Hz, and in the medium to high frequency band of 3500 Hz or more, a transmission loss is shown that is significant compared to the comparative example. That is, in Example 4, the sound insulation performance is improved in a wide range of frequency bands, and significant sound insulation performance can be obtained for a specific frequency band.

[0043] 5, the aperture ratio R of this embodiment is based on the aperture area of ​​the opening 61 in a top view. 0 As described above, the openings 61 are regularly arranged in the area of ​​the intermediate layer 6 divided into 10 cm squares when viewed from above. 0 is 100cm 2 It becomes.

[0044] The aperture ratio R may be approximately 20% or more. Furthermore, the aperture ratio R may be 50% or more, and more preferably, the aperture ratio R is 75% or more. In this embodiment, the aperture ratio R is approximately 50%. The aperture 61 in this embodiment is formed as a square with each side measuring approximately 7 cm.

[0045] The sound-insulating material 1 of the present disclosure forms an air layer 62 between the first layer 2 and the second layer 4. This allows the sound-insulating material 1 to have a double-wall structure with the air layer 62, which is a hollow space, sandwiched between them. Furthermore, the sound-insulating material 1 can be made lighter than a solid sound-insulating material of the same volume, and the first layer 2 and the second layer 4 being porous also enable the lighter weight to be achieved.

[0046] Furthermore, the first porous body, the second porous body and the third porous body may be formed of a non-permeable porous body, more preferably a closed-cell foam having air bubbles trapped in each cell, so that the sound insulation material 1 exhibits characteristic sound insulation properties and can further reduce sound waves transmitted through the first layer 2, the second layer 4 and the intermediate layer 6.

[0047] Furthermore, the intermediate layer 6 may have an air layer 62 formed by the opening 61. This allows the sound-insulating material 1 to easily obtain a desired aperture ratio R by changing the size of the opening 61. This allows the sound-insulating material 1 to obtain a high transmission loss in a desired frequency band.

[0048] Furthermore, the intermediate layer 6 may have a plurality of regularly arranged openings 61. This allows the sound-insulating material 1 to obtain uniform sound-insulating performance over the entire range in the X and Y directions, and also provides a significant effect due to the regularly arranged openings, for example, a significant increase in the transmission loss in the low frequency band.

[0049] As described above, according to the sound-proofing material of the present disclosure, a new sound-proofing material can be provided that can easily adjust the frequency band to be blocked and also achieves lightweight construction.

[0050] Although the present disclosure has been described above with reference to the embodiment, the present disclosure is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the invention. In particular, the multiple modifications described in this specification can be arbitrarily combined as necessary.

[0051] For example, in the above embodiment, the rectangular parallelepiped sound-insulating material 1 has been described as an example, but the present disclosure is not limited thereto. For example, the shape of the sound-insulating material 1 can be appropriately changed according to the shape of the mounting location of the vehicle C. In this case, it is desirable that the first layer 2 or the second layer 4 of the sound-insulating material 1 is disposed so as to face the noise source. This allows the first layer 2, the second layer 4, and the intermediate layer 6 to be disposed so as to intersect with the sound waves transmitted from the noise source. As a result, the sound-insulating material 1 can be disposed so as to block the sound waves emitted by the noise source by the double-wall structure.

[0052] In the above embodiment, the opening 61 forms a hollow air layer 62, but the present disclosure is not limited to this. The inside of the opening 61 may be filled with a material having a lower density than the first porous body, the second porous body, and the third porous body. For example, the opening 61 may be filled with felt, wool, or a fibrous material.

[0053] Furthermore, in the above embodiment, the first layer 2 and the second layer 4 are formed to have the same thickness, but the present disclosure is not limited to this. The first layer 2, the second layer 4, and the intermediate layer 6 may be formed to have different thicknesses. In addition, the thicknesses of the first layer 2, the second layer 4, and the intermediate layer 6 may be determined by dividing the entire thickness of the sound insulation material 1, which is set based on the size of the space in which the sound insulation material 1 is installed, into three equal parts. [Explanation of symbols]

[0054] 1: Sound insulation material 2: First layer 4: Second layer 6: Middle layer 61: Opening 62: Air layer R: Opening ratio

Claims

1. a first layer formed of a first porous body; a second layer that is disposed opposite the first layer with an air layer interposed therebetween and is formed of a second porous body; A sound-proofing material comprising:

2. An intermediate layer is disposed between the first layer and the second layer and is formed of a third porous body. The intermediate layer forms the air layer. The sound insulation material according to claim 1.

3. The first layer and the second layer are formed of a non-permeable porous body. The sound insulation material according to claim 1.

4. the intermediate layer has an opening for forming the air layer, The aperture ratio of the opening is 20% or more. The sound insulation material according to claim 2.

5. The intermediate layer has a plurality of the openings regularly arranged. The sound insulation material according to claim 4.

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