JPH06118965A - Sound absorbing material and its manufacture - Google Patents

Abstract

PURPOSE:To provide a sound absorbing material which has optimum acoustic absorptivity and its manufacture which employs a simple process and high in yield. CONSTITUTION:Coarse grain 1 of an inorganic material of 0.8-3.0mm grain size and fine grain 2 of an inorganic material of 0.1-0.8mm grain size are mixed at a 95:5-50:50wt. blending ratio, and compacted by being heated and cured together with a 1-10wt.% resin composition, so sound absorbing material having various gap rates can be formed and the acoustic absorptivity is controllable according to a blending ratio. The optimum acoustic absorptivity is therefore obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound absorbing material made of a granular material used for a sound deadening body, a soundproof wall and the like, and a method for manufacturing the same.

[0002]

2. Description of the Related Art As a conventional sound absorbing material using a granular material,
It is known to use sand, gravel, and open-grained ascon. Regarding the sound absorbing material having such a structure, a relationship between the particle size and the sound absorbing property has been reported. according to this,
As a result of measuring the sound absorption coefficient by changing the particle size of the sound absorbing material having the same thickness, the larger the particle size, that is, the larger the void ratio, the higher the sound absorption coefficient is, and the higher the sound absorption coefficient is. It has been revealed.

[0003]

In recent years, since the sound absorbing material is used for various purposes and places, various sound absorbing coefficients and frequency characteristics are required. In particular, a sound absorbing material used for noise control is desired to have good sound absorbing characteristics in a wide frequency band. Under such circumstances, in order to obtain the optimum sound absorption coefficient with the conventional sound absorbing material, it is necessary to classify particles having a uniform particle size by sieving, which causes a complication of work and a decrease in yield. It was

The present invention was devised in order to solve the above-mentioned drawbacks of the prior art, and it is possible to manufacture a sound absorbing material having an optimum sound absorbing coefficient in a simple process and at a high yield. It is an object of the present invention to provide a sound absorbing material and a manufacturing method thereof.

[0005]

In order to solve the above-mentioned problems, in the sound absorbing material according to claim 1, a coarse particle having an inorganic material particle diameter of 0.8 to 3.0 mm and an inorganic material having a particle diameter of 0.8 to 3.0 mm are used. Compounding ratio of fine particles having a particle diameter of 0.1 to 0.8 mm of 95: 5 to 50:
It is characterized in that it is mixed at a ratio of 50% by weight, heat-cured with a resin composition of 1 to 10% by weight and molded.

Here, as the inorganic material, natural stone, sand,
Ceramic particles, metal powder, etc. are used. Further, isocyanate, polyol and the like are used in the resin composition.

Further, in the method of manufacturing a sound absorbing material according to claim 2, (a) the particle diameter of the inorganic material is 0.8 to 3.0 m.
m coarse particles and fine particles of inorganic material having a particle diameter of 0.1 to 0.8 mm are mixed at a compounding ratio of 95: 5 to 50:50 by weight,
A first step of obtaining a first mixture, (b) a second step of adding 1 to 10 wt% of a resin composition to the mixture to obtain a second mixture, (c) a mold of the second mixture It is characterized in that it comprises a third step in which the resin composition is filled in, and cured by heating at a temperature not lower than the curing temperature of the resin composition.

As the weight ratio, for example, the compounding ratio shown in Table 1 is used.

[Table 1]

[0009]

In the invention described in claim 1, a mixture of coarse particles of inorganic material having a particle diameter of 0.8 to 3.0 mm and fine particles of inorganic material having a particle diameter of 0.1 to 0.8 mm is blended. By changing the ratio, the sound absorbing characteristics of the sound absorbing material can be variously changed.

According to the invention of claim 2, (a)
A mixing ratio of coarse particles of inorganic material having a particle diameter of 0.8 to 3.0 mm and fine particles of inorganic material having a particle diameter of 0.1 to 0.8 mm is 95:
Since the first step of obtaining the first mixture by mixing at a weight ratio of 5 to 50:50 is provided, it is not necessary to classify particles having a uniform particle size by sieving.

The present invention will be further described below based on an example shown in the drawings. FIG. 1 is a view showing a cross section of a sound absorbing material of the present invention. In the figure, reference numeral 1 is a particle diameter of an inorganic material 0.8 to 3.
Coarse particles of 0 mm, reference numeral 2 is a particle diameter of the inorganic material is 0.1 to 0.1
It is a fine grain of 0.8 mm. The coarse particles 1 and the fine particles 2 are mixed at an appropriate mixing ratio. The illustrated sound absorbing material A is obtained by heating and curing such a mixture. Code 5
Is the sound incident on the sound absorbing material A, and the sound absorbing characteristic of the sound absorbing material A changes depending on the mixing ratio of the coarse particles 1 and the fine particles 2.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

(Example 1) As shown in Table 1, a mixture ratio of coarse particles (particle diameter 0.8 to 2.8 mm) and fine particles (particle diameter 0.18 to 0.5 mm) of ceramic particles was 275: 25. 7% by weight of isocyanate and polyol (Sumitomo Bayer Urethane Co., Ltd.) were added to the mixture mixed in the weight ratio of and stirred.
The mixture thus obtained was filled in a cylindrical mold (hereinafter referred to as a mold a) and heat-cured for 15 minutes in an environment of 120 ° C. to obtain a sound absorbing sound having a plate-like unevenness of 25 mm thickness. Material B1 (see Table 1) was obtained. The sound absorbing material B1 has the same cross-sectional grain shape as the sound absorbing material A shown in FIG. 1 (FIG. 6A).
reference). Hereinafter, the weight ratio of the coarse particles to the fine particles of the ceramic particles was changed as shown in Table 1 and other treatments were the same, and sound absorbing materials B2 to B5 and Comparative Example BH were obtained.

(Embodiment 2) Further, in place of the above-mentioned mold, a mold (hereinafter referred to as a mold b) provided with a recess (thickness of about 20 mm) is provided with the mixture (coarse particles of ceramic particles (particles). Diameter 0.8-2.8mm) and fine particles (particle diameter 0.18-0.5)
mm) in a mixing ratio of 275: 25 and a mixture obtained by adding 7% by weight of isocyanate and polyol (Sumitomo Bayer Urethane Co., Ltd.) to a total layer thickness of about 45 mm. Then, when heat curing is performed for 15 minutes in an environment of 120 ° C., a sound absorbing material A1 (45 mm thick (including back air layer 3)) shown in FIG. It was

Next, the normal incident sound absorption coefficient in the frequency band 250 Hz to 4000 Hz of the sound absorbing materials B1 to B5 and the comparative example was measured. The results are shown in FIGS. 2 (a) and 2 (b).
Reference H is a comparative example. From these graphs, it is clear that the sound absorption characteristics are changed by mixing the ceramic particles having different particle sizes (coarse particles 1 and fine particles 2).

Thus, according to FIGS. 2 (b) and 2 (a), as the mixing ratio of the fine particles 2 increases, the sound absorption peak reaches from about 1900 Hz to about 1800 Hz, 15
It is apparent that after passing around 50 Hz, it shifts around 1450 Hz, that is, from the high frequency band to the low frequency band in order. However, from B4 and B5 in FIG. 2A, it is not necessary to simply increase the ratio of the fine particles 2 in order to shift the sound absorption coefficient peak to the low frequency side. It shows that the effect of does not appear depending on the compounding ratio. Therefore, coarse grain 1 and fine grain 2
It was found that the mixing ratio of 95: 5 to 50:50 by weight shows good sound absorption coefficient and frequency characteristics, which is the reason for limiting the present invention.

Next, FIG. 3A shows the sound absorbing material B2 (see FIG. 6).
(See (a)), and when a sound absorbing material B2 ′ (see FIG. 6 (b)) is measured by adding a back air layer of 20 mm to B2.
(B) is the case where the sound absorbing material B3 is used as the measurement sample (B3 ′ is B
2'includes a back air layer of 20 mm), and FIG. 4 shows a frequency band of 250 Hz when the sound absorbing material BH is used as a measurement sample.
The normal incidence sound absorption coefficient at ˜4000 Hz (BH ′ is the sound absorption coefficient when the back air layer of 20 mm is included) is shown.

In FIGS. 3 and 4, the sound absorbing material B is shown.
2 and B2 ', sound absorbing materials B3 and B3', sound absorbing materials BH and B
Comparing H'with each other, the back air layer 3 (20 mm layer)
It is better to provide the middle / high range (especially 250Hz-100
Good sound absorption coefficient is shown in the frequency band of 0 Hz and 3000 Hz or more). In addition, FIG.
The sound absorption peaks of the sound absorbing materials B2 ′, B3 ′, BH ′ shown in (b) and FIG. 4 are around 500 Hz. That is, it exhibits excellent sound absorption characteristics in the low frequency band. Therefore, it is optimal for absorbing noise in the low frequency band around 500 Hz generated in air ducts, home appliances and the like.

Further, a material filled with a fiber type sound absorbing material such as glass wool (see FIGS. 5 (a) and 5 (b)) instead of the back air layer 3 has a frequency band 1000 compared to the sound absorbing material B.
Good sound absorption coefficient in the vicinity of Hz to 2000 Hz.
Therefore, by using the sound absorbing materials A and B made of the granular material and the fibrous sound absorbing material in combination in the first and second embodiments, it is possible to cover the decrease in the sound absorbing coefficient of the sound absorbing material B at 1000 Hz to 2000 Hz. it can.

[0020]

As described above, according to the present invention,
A mixing ratio of coarse particles of inorganic material having a particle diameter of 0.8 to 3.0 mm and fine particles of inorganic material having a particle diameter of 0.1 to 0.8 mm is 95:
Since it was mixed at a ratio of 5 to 50:50 and heat-cured with a resin composition of 1 to 10% by weight, it was possible to create sound absorbing materials with various void ratios, and the sound absorbing characteristics were controlled by the mixing ratio. can do. Therefore, there is an effect that the optimum sound absorption coefficient can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a sound absorbing material according to an embodiment of the present invention.

2 is a frequency band of the sound absorbing material of Example 1 of 250 Hz to
It is a figure which shows the sound absorption coefficient of 4000 Hz.

FIG. 3 is a frequency band 2 of the sound absorbing materials of Examples 1 and 2;
It is a figure which shows the sound absorption coefficient of 50 Hz-4000 Hz.

FIG. 4 is a frequency band 2 of the sound absorbing materials of Example 1 and Example 2;
It is a figure which shows the sound absorption coefficient of 50 Hz-4000 Hz.

FIG. 5 is a conceptual sectional view of a sound absorbing material in which glass wool is used instead of the back air layer 3 of the example.

FIG. 6 is a conceptual sectional view of a sound absorbing material of an example.

[Simple explanation of symbols]

A, A1 to A5, AH, B, B1 to B5, BH ... Sound absorbing material, 1 ... Coarse particles, 2 ... Fine particles, 3 ... Back air layer, 4 ...
… Hard walls, 5 …… Sound, 6 …… Glass wool.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Kaneko 10-1 Nakazawa-machi, Hamamatsu-shi, Shizuoka Prefecture Yamaha Stock Company

Claims (2)

[Claims] 1. A compounding ratio of coarse particles of an inorganic material having a particle diameter of 0.8 to 3.0 mm and fine particles of an inorganic material having a particle diameter of 0.1 to 0.8 mm in a weight ratio of 95: 5 to 50:50. Mix with 1 to 1
A sound absorbing material molded by heating and curing with a resin composition of 0% by weight. 2. (a) Particle size of inorganic material 0.8 to 3.0
mm coarse particles and fine particles of inorganic material having a particle diameter of 0.1 to 0.8 mm are mixed at a compounding ratio of 95: 5 to 50:50 by weight to obtain a first mixture. b) a second step of adding 1 to 10% by weight of the resin composition to the mixture to obtain a second mixture, (c) filling a mold with the second mixture, and curing temperature of the resin composition A method of manufacturing a sound absorbing material, comprising the above third step of curing by heating and molding.