Sound-absorbing material

Abstract

To provide a sound absorption material capable of reducing a total thickness and increasing a sound absorption coefficient based on JIS A1405 to 0.5 or higher within a frequency range of 100-500 Hz.SOLUTION: A sound absorption material 1 comprises two layers of a resin film layer 10 of a sound generation source side and a soft polyurethane foam layer 20 laminated on the resin film layer 10. The resin film layer 10 has a density of 0.9-1.5 g / cm3, a thickness of 1-4 mm, and a surface density of 0.09-0.60 g / cm2. The soft polyurethane foam layer 20 has a density of 0.015-0.1 g / cm3, a thickness of 10-50 mm, and a surface density of 0.015-0.50 g / cm2. A sound absorption coefficient based on JIS A1405 has a maximum value of 0.5 or higher within a frequency range of 100-500 Hz.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a sound-absorbing material.

Background Art

[0002] As one of the noise countermeasures, it is common to surround the noise source with a sound-absorbing material, and various sound-absorbing materials have been proposed. For example, in the sound-absorbing material disclosed in Patent Document 1, it has a mass part and a spring part. The spring part is set facing the installation surface, and the mass part is arranged on the sound source side. The mass part is composed of a resin film with a thickness of 0.2 mm and glass wool with a thickness of 25 mm, and the spring part is composed of glass wool with a thickness of 200 mm, so that it has sound absorption in the low-frequency range of 63 to 125 Hz to the frequency range of 200 to 5000 Hz.

[0003] Further, in the sound-absorbing material (sound-absorbing structure) disclosed in Patent Document 2, a film vibration sound-absorbing material (plate-like laminate) in which a plate-like body having a large number of openings and a thin film are laminated is used as the sound source side, and a soft fiber-based porous sound-absorbing material or a continuous bubble type elastic foam and a sound insulation board are arranged behind it. The plate-like laminate is, for example, a resin film with a thickness of 4 to 25 μm, and the continuous bubble type elastic foam is a urethane foam with a thickness of 100 to 150 mm, so that it not only absorbs sound in the medium and high frequency range of 400 Hz or more, but also absorbs sound in the low frequency range of 100 to 300 Hz.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] On one hand, as a case where noise countermeasures using a sound-absorbing material are necessary, for example, there are those for road noise generated from the friction between a tire and the ground and operating sounds of motors of home appliances. In addition to requiring sound absorption in the frequency range of 500 Hz or less, it is necessary to attach the sound-absorbing material in a narrow and limited space. However, although any of the sound-absorbing materials in Patent Documents 1 and 2 can ensure sound absorption in a specific frequency range by adjusting the thickness and surface density of the film layer and the polyurethane layer, there is a problem that it is difficult to attach them in a narrow and limited space because the total thickness as a sound-absorbing material is thick.

[0006] The present invention has been made in view of such problems, and an object thereof is to provide a sound-absorbing material having a reduced total thickness and a sound absorption rate of 0.5 or more based on JIS A 1405 in the frequency range of 100 to 500 Hz.

Means for Solving the Problems

[0007] The sound-absorbing material of the present invention for solving the above problems is a resin film layer on the sound source side, and a soft polyurethane foam layer laminated on the resin film layer, and consists of two layers, the resin film layer has a density of 0.9 to 1.5 g / cm 3 a thickness of 1 to 4 mm, and a surface density of 0.09 to 0.60 g / cm 2 and is the soft polyurethane foam layer has a density of 0.015 to 0.1 g / cm 3 a thickness of 10 to 50 mm, and a surface density of 0.015 to 0.50 g / cm 2 and is characterized by having a maximum sound absorption rate of 0.5 or more in the frequency range of 100 to 500 Hz based on JIS A 1405.

[0008] the resin film layer has a surface density of 0.09 to 0.45 g / cm 2 and the soft polyurethane foam layer has a surface density of 0.015 to 0.13 g / cm 2 ​It is preferable that the sound absorption rate has a maximum value of 0.6 or more in the frequency range of 100 to 500 Hz.

Advantages of the Invention

[0009] According to the present invention, it is possible to provide a sound-absorbing material that has a reduced total thickness and a sound absorption rate based on JIS A 1405 of 0.5 or more in the frequency range of 100 to 500 Hz.

Brief Description of the Drawings

[0010]

Figure 1

Embodiments for Carrying Out the Invention

[0011] Hereinafter, an embodiment of the sound-absorbing material of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the sound-absorbing material 1 of the present invention is composed of two layers: a resin film layer 10 on the sound source side and a soft polyurethane foam layer 20 laminated on the resin film layer 10. The resin film layer 10 has a density of 0.9 to 1.5 g / cm 3 , a thickness of 1 to 4 mm, and a surface density of 0.09 to 0.60 g / cm 2 . Further, the soft polyurethane foam layer 20 has a density of 0.015 to 0.1 g / cm 3 , a thickness of 10 to 50 mm, and a surface density of 0.015 to 0.50 g / cm 2 . Thereby, the sound-absorbing material 1 is assumed to have a maximum sound absorption rate based on JIS A 1405 of 0.5 or more in the frequency range of 100 to 500 Hz.

[0012] The sound-absorbing material 1 is designed such that, depending on the combination of the respective density, thickness, and surface density ranges of the resin film layer 10 on the sound source side and the soft polyurethane foam layer 20 laminated on the back side opposite to the sound source side, it has a maximum value of the sound absorption rate of 0.5 or more in the frequency range of 100 to 500 Hz based on JIS A 1405 (measurement of the normal incidence sound absorption rate measured by JIS A 1405). The frequency at which the sound-absorbing material 1 has a maximum value is, for example, any one of 100 Hz, 125 Hz, 160 Hz, 200 Hz, 250 Hz, 315 Hz, 400 Hz, and 500 Hz, and the sound absorption rate is set to 0.5 or more.

[0013] The sound-absorbing material 1 has the thickness of the resin film layer 10 set to 1 to 4 mm and the thickness of the soft polyurethane foam layer 20 set to 10 to 50 mm. In any combination, the total thickness of the sound-absorbing material 1 is in the range of 11 to 54 mm. Compared with those whose previous total thickness exceeded 150 mm or 200 mm, it becomes significantly thinner and can be attached to a narrowly limited space. Furthermore, the layer thickness of the sound-absorbing material 1 is preferably 50 mm or less, more preferably 40 mm or less, so as to be able to cope with a narrowly limited space.

[0014] There is no particular limitation on the material of the resin film layer 10, and its thickness is set to 1 to 4 mm. As the resin film layer 10, a relatively thick one is used. The resin film layer 10 is arranged on the sound source side, receives sound waves, causes membrane vibration, and absorbs the energy of sound by the vibration. The resin film layer 10 tends to show a tendency that the frequency at which the sound absorption rate reaches a maximum increases as the thickness becomes thinner. When the thickness of the resin film layer 10 is less than 1 mm and thin, the generation of membrane vibration by sound waves is suppressed, and when it exceeds 4 mm and is thick, it becomes difficult for membrane vibration to occur. For the resin film layer 10, resins such as vinyl chloride-based resins, polyethylene-based resins, polypropylene-based resins, fluorinated ethylene-based resins, and acrylic-based resins are used.

[0015] The resin film layer 10 has a density of 0.9 to 1.5 g / cm 3 and a surface density of 0.09 to 0.60 g / cm 2is set. By setting the density of the resin film layer 10 to 0.9 to 1.5 g / cm 3 and adjusting the thickness to 1 to 4 mm, the surface density is set to 0.09 to 0.60 g / cm 2 within the range. In this way, the two-layer sound-absorbing material 1 composed of the resin film layer 10 whose surface density is adjusted by changing the density and thickness and combining them, and the soft polyurethane foam layer 20 described later can have a maximum value such that the sound absorption rate based on JIS A1405 is 0.5 or more in the frequency range of 100 to 500 Hz.

[0016] The soft polyurethane foam layer 20 is laminated on the side opposite to the sound source of the resin film layer 10. When the soft polyurethane foam layer 20 is laminated on the resin film layer 10, it is not necessarily required to adhere, and it is sufficient that the soft polyurethane foam layer 20 is in a state of being in contact with the resin film layer 10 without a gap and can convert the vibration energy of the resin film layer 10 into heat energy for sound absorption.

[0017] The soft polyurethane foam layer 20 has a density of 0.015 to 0.1 g / cm 3 , a thickness of 10 to 50 mm, and a surface density of 0.015 to 0.50 g / cm 2 is set. By setting the density of the soft polyurethane foam layer 20 to 0.015 to 0.1 g / cm 3 and adjusting the thickness to 10 to 50 mm, the surface density is set to 0.015 to 0.50 g / cm 2 within the range. In this way, by combining the resin film layer 10 with the soft polyurethane foam layer 20 whose density, thickness, and surface density ranges are adjusted, the sound-absorbing material 1 can have a maximum value such that the sound absorption rate based on JIS A1405 is 0.5 or more in the frequency range of 100 to 500 Hz.

[0018] The soft polyurethane foam layer 20 has a surface density in the range of 0.015 to 0.13 g / cm 2 and a surface density of 0.09 to 0.45 g / cm 2In combination with the resin film layer 10, the sound-absorbing material 1 can have a maximum sound absorption rate of 0.6 or more in the frequency range of 100 to 500 Hz based on JIS A 1405.

[0019] By laminating such a resin film layer 10 and a soft polyurethane foam layer 20, the resin film layer 10 has a density of 0.9 to 1.5 g / cm 3 , a thickness of 1 to 4 mm, and a surface density of 0.09 to 0.60 g / cm 2 . Also, the soft polyurethane foam layer 20 has a density of 0.015 to 0.1 g / cm 3 , a thickness of 10 to 50 mm, and a surface density of 0.015 to 0.50 g / cm 2 In the sound-absorbing material 1 configured as described above, the total thickness can be made 54 mm or less, and it can be provided with a specific sound absorption rate peak with a sound absorption rate of 0.5 or more in the frequency range of 100 to 500 Hz. Moreover, since the total thickness is as thin as 54 mm or less, it can be attached even in a narrow and limited space, such as inside a tire cavity or a tire house. Since the thickness of the resin film layer 10 of the sound-absorbing material 1 is 1 to 4 mm, wrinkles are less likely to occur even when the sound-absorbing material 1 is attached to a curved surface, and it can be installed without reducing the sound absorption effect. Also, in the sound-absorbing material 1, since the resin film layer 10 is laminated on the soft polyurethane foam layer 20, it is possible to impart Nox gas resistance, oil resistance, and waterproofness to the urethane foam, and the range of use of the sound-absorbing material 1 can be expanded. Also, the sound-absorbing material 1 can be manufactured simply by laminating the soft polyurethane foam layer 20 on the resin film layer 10. The soft polyurethane foam layer 20 does not require a special formulation, and the soft polyurethane foam layer 20 and the sound-absorbing material 1 can be easily manufactured.

[0020] In the sound-absorbing material 1, when the resin film layer 10 sets the soft polyurethane foam layer 20 under certain conditions and adjusts the density and thickness to reduce the surface density, the frequency at which the sound absorption rate reaches a maximum tends to increase. For example, when the surface density is 0.60 g / cm 2 , 0.30 g / cm 2 , 0.21 g / cm2 , 0.16 g / cm 2 , 0.09 g / cm 2 When it is changed to, the frequencies showing the maximum sound absorption rates change to 100 Hz, 160 Hz, 250 Hz, 315 Hz, 400 Hz, and 500 Hz. Also, in the sound absorption material 1, in the soft polyurethane foam layer 20, when the resin film layer 10 is under certain conditions and the surface density becomes smaller by adjusting the density and thickness, the frequency at which the sound absorption rate becomes maximum tends to increase. For example, when the surface density is 0.20 cm 2 , 0.05 g / cm 2 , 0.015 g / cm 2 When it is changed to, the frequencies showing the maximum sound absorption rates change to 200 Hz, 250 Hz, and 315 Hz. Furthermore, when the surface density of the soft polyurethane foam layer 20 is in the range of 0.015 to 0.13 g / cm 2 and combined with the resin film layer 10 having a surface density of 0.09 to 0.45 g / cm 2 the sound absorption material 1 can have a maximum sound absorption rate of 0.6 or more in the frequency range of 100 to 500 Hz based on JIS A 1405.

Example

[0021] Next, examples of the present invention will be described together with comparative examples, but these examples do not limit the present invention in any way. Hereinafter, the relationship between the sound absorption rate and the frequency of the sound absorption material 1 for specific combinations of density, thickness, and surface density of the resin film layer 10 and the soft polyurethane foam layer 20 (Examples 1 to 13 and Comparative Examples 1 to 5) was measured, and the results are shown in Table 1.

[0022] <Evaluation of sound absorption rate> The evaluation of the sound absorption rate was measured by the normal incidence sound absorption rate measurement based on JIS A 1405, and the sound absorption rates at frequencies of 100 Hz, 125 Hz, 160 Hz, 200 Hz, 250 Hz, 315 Hz, 400 Hz, and 500 Hz were measured. In addition, the sound absorption rates at 630 Hz and 800 Hz were also measured.

[0023] <Evaluation of workability> Assume a case where a sound-absorbing material is attached to the inner wall as a noise source, and the workability in terms of ease of attachment and followability was evaluated in three levels: ○, △, and ×.

[0024] <Example 1> The density of the resin film layer 10 was 1.5 g / cm 3 , the thickness was 3 mm, and the areal density was 0.45 g / cm 2 , and the density of the soft polyurethane foam layer 20 was 0.025 g / cm 3 , the thickness was 20 mm, and the areal density was 0.50 g / cm 2 , and the sound-absorbing material 1 was obtained by laminating them in two layers. In this sound-absorbing material 1, the sound absorption rate based on JIS A 1405 had a maximum value of 0.6 at 160 Hz and a value of 0.5 at 125 Hz in the frequency range of 100 to 500 Hz. Also, regarding workability, there were no particular problems in the work.

[0025] <Examples 2 - 6> Except that the density and thickness of the resin film layer 10 were adjusted so that the areal density was changed to 0.30, 0.21, 0.16, 0.09 g / cm 2 , it was the same as in Example 1. The evaluation results of each sound-absorbing material 1 in this case were as described in Table 1. When the areal density of the resin film layer 10 decreased, the frequency of the maximum value of the sound absorption rate increased to 250, 315, 400, 500 Hz.

[0026] <Examples 7 - 8> The conditions of the resin film layer 10 (areal density was 0.42 g / cm 2 ) were kept constant, and the thickness of the soft polyurethane foam layer 20 was adjusted so that the areal density was changed to 0.11, 0.30 g / cm 2 . The evaluation results of each sound-absorbing material 1 in this case were as described in Table 1. When the areal density of the soft polyurethane foam layer 20 decreased, the frequency of the maximum value of the sound absorption rate increased to 125 Hz, 200 Hz.

[0027] <Examples 9 - 10> The conditions of the resin film layer 10 (areal density was 0.30 g / cm 2Set [[ID=]] to a constant value, and adjust the thickness of the soft polyurethane foam layer 20 so that the surface density is 0.015, 0.03 g / cm 2 The evaluation results of each sound absorber 1 in this case were as described in Table 1. The frequency of the maximum value of the sound absorption rate was 315 Hz for all cases.

[0028] <Example 11> The thickness of the soft polyurethane foam layer 20 was changed to 50 mm (the surface density was 0.13 g / cm 2 ) Otherwise, it was the same as in Example 4. The evaluation results of the sound absorber 1 in this case were as described in Table 1. The frequency of the maximum value of the sound absorption rate was 200 Hz.

[0029] <Example 12> The density of the soft polyurethane foam layer 20 was changed to 0.1 g / cm 3 Otherwise, it was the same as in Example 2. The evaluation results of the sound absorber 1 in this case were as described in Table 1. The frequency of the maximum value of the sound absorption rate was 200 Hz.

[0030] <Example 13> The density and thickness of the resin film layer 10 were adjusted to change the surface density (the surface density was 0.60 g / cm 2 ) Otherwise, it was the same as in Example 1. The evaluation results of the sound absorber 1 in this case were as described in Table 1. The frequency of the maximum value of the sound absorption rate was 100 Hz.

[0031] <Example 14> The density of the resin film layer 10 was 0.9 g / cm 3 , the thickness was 4 mm, and the surface density was 0.36 g / cm 2 The density of the soft polyurethane foam layer 20 was 0.1 g / cm 3 , the thickness was 50 mm, and the surface density was 0.5 g / cm 2 A sound absorber 1 laminated in two layers was obtained. The evaluation results of the sound absorber 1 in this case were as described in Table 1. The frequency of the maximum value of the sound absorption rate was 100 Hz.

[0032] <Example 15> The surface density was changed by adjusting the density and thickness of the resin film layer 10 (the surface density was 0.18 g / cm 2 ), and it was the same as Example 8 otherwise. The evaluation results of the sound-absorbing material 1 in this case were as described in Table 1. The frequency of the maximum value of the sound absorption rate was 500 Hz.

[0033] <Comparative Example 1> The surface density was made 0.01 g / cm by setting the thickness of the soft polyurethane foam layer 20 to 5 mm 2 , and it was the same as Example 4 otherwise. The evaluation results of the sound-absorbing material 1 in this case were as described in Table 1. The frequency of the maximum value of the sound absorption rate was 630 Hz, and there was no maximum value at 500 Hz or lower.

[0034] <Comparative Example 2> The surface density was changed by adjusting the density and thickness of the resin film layer 10 (the surface density was 0.01 g / cm 2 ), and it was the same as Example 1 otherwise. The evaluation results of the sound-absorbing material 1 in this case were as described in Table 1. The frequency of the maximum value of the sound absorption rate was 800 Hz, and there was no maximum value at 500 Hz or lower.

[0035] <Comparative Example 3> It was the same as Example 1 except that only the soft polyurethane foam layer 20 was used without laminating the resin film layer 10. The evaluation results of the sound-absorbing material 1 in this case were as described in Table 1. The frequency of the maximum value of the sound absorption rate was 800 Hz, and there was no maximum value at 500 Hz or lower.

[0036] <Comparative Example 4> It was the same as Example 2 except that only the resin film layer 10 was used without laminating the soft polyurethane foam layer 20. The evaluation results of the sound-absorbing material 1 in this case were as described in Table 1. There was no maximum value of 0.5 or more in the sound absorption rate.

[0037] <Comparative Example 5> The surface density was changed by adjusting the density and thickness of the resin film layer 10 (the surface density was 0.70 g / cm 2Except for the above, it is the same as in Example 1. The evaluation results of the sound-absorbing material 1 in this case were as described in Table 1. The maximum value of the sound absorption rate could not be measured.

[0038] <Comparative Example 6> Except that the thickness of the soft polyurethane foam layer 20 was set to 60 mm and the surface density was 0.15 g / cm 2 it was the same as in Example 1. The evaluation results of the sound-absorbing material 1 in this case were as described in Table 1. The maximum value of the sound absorption rate could not be measured.

[0039] From Table 1 showing the evaluation results of the sound-absorbing material 1 conducted for the above Examples and Comparative Examples, it was confirmed that in Examples 1 to 15 of the present invention, the total thickness of the sound-absorbing material 1 could be made 54 mm or less, and it had a specific maximum value (peak) of the sound absorption rate of 0.5 or more in the frequency range of 100 to 500 Hz. On the other hand, in Comparative Examples 1 to 6, it was confirmed that even if the total thickness of the sound-absorbing material 1 could be made 54 mm or less, it could not be made to have a specific maximum peak of the sound absorption rate of 0.5 or more in the frequency range of 100 to 500 Hz.

[0040]

Table 1

[0041] As described specifically together with the embodiments above, the sound-absorbing material 1 of the present invention is composed of two layers, namely, a resin film layer 10 on the sound source side and a soft polyurethane foam layer 20 laminated on the resin film layer 10. The resin film layer 10 has a density of 0.9 to 1.5 g / cm 3 , a thickness of 1 to 4 mm, and a surface density of 0.09 to 0.60 g / cm 2 , and the soft polyurethane foam layer 20 has a density of 0.015 to 0.1 g / cm 3 , a thickness of 10 to 50 mm, and a surface density of 0.015 to 0.50 g / cm 2 , and is configured to have a maximum value of the sound absorption rate of 0.5 or more in the frequency range of 100 to 500 Hz based on JIS A1405. According to such a configuration, the total thickness can be made 54 mm or less, and it can be provided with a specific sound absorption rate peak having a sound absorption rate of 0.5 or more in the frequency range of 100 to 500 Hz. In addition, since the total thickness is as thin as 54 mm or less, it can also be attached to a narrow and limited space, for example, inside the tire cavity or in the tire house.

[0042] In addition, the resin film layer has a surface density of 0.09 to 0.45 g / cm 2 and the soft polyurethane foam layer 20 has a surface density of 0.015 to 0.13 g / cm 2 and is configured to have a maximum value of 0.6 or more in the frequency range of 100 to 500 Hz for the sound absorption rate. According to such a configuration, by adjusting the density and thickness of the soft polyurethane foam layer 20, the surface density is in the range of 0.015 to 0.13 g / cm 2 and the sound absorption material 1 combined with the resin film layer 10 having a surface density of 0.09 to 0.45 g / cm 2 can have a maximum value of the sound absorption rate based on JISA1405 of 0.6 or more in the frequency range of 100 to 500 Hz. Thereby, it can be made into a sound absorption material with an even higher sound absorption rate corresponding to the frequency of the sound generation source.

[0043] Note that the present invention is not limited to the above-described embodiment at all.

Explanation of reference numerals

[0044] 1 Sound absorption material 10 Resin film layer 20 Soft polyurethane foam layer

Claims

Claim 1 a resin film layer on the sound source side, and a soft polyurethane foam layer laminated on the resin film layer, consisting of two layers, The resin film layer has a density of 0.9 to 1.5 g / cm 3 , a thickness of 1 to 4 mm, and a surface density of 0.09 to 0.60 g / cm 2 and is set to The soft polyurethane foam layer has a density of 0.015 to 0.1 g / cm 3 , a thickness of 10 to 50 mm, and a surface density of 0.015 to 0.50 g / cm 2 and is set to having a maximum value of 0.5 or more in the frequency range of 100 to 500 Hz based on JIS A1405, characterized in that it is a sound-absorbing material. Claim 2 The resin film layer has a surface density of 0.09 to 0.45 g / cm 2 and is set to The soft polyurethane foam layer has a surface density of 0.015 to 0.13 g / cm 2 and has a maximum value of 0.6 or more in the frequency range where the sound absorption rate is 100 to 500 Hz. The sound-absorbing material according to claim 1, characterized in that.

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