JPH05204385A - Sound absorbent - Google Patents

Abstract

PURPOSE:To obtain a desirable sound absorptivity and strength of adhesion and to eliminate the need for reinforcing materials by specifying the grain size and percentage of voids of a ceramic particle layer which is press molded together with an adhesive. CONSTITUTION:The grain size of the ceramic particle layer which is press molded together with the adhesive is specified to 0.1 to 1mm and the percentage of voids specified to 30 to 45vol.%. Namely, the voids of the absorbent act to absorb the energy of incident sounds. A function to reflect sounds increases too much and the sound absorptivity degrades if the percentage of voids is below 30%. The transmittance of the sounds increases if the percentage of voids conversely exceeds 45% and, therefore, the percentage of voids is limited to 30 to 45%. The voids are clogged and the sound absorption performance degrades if the particle size of the ceramic part is below 0.1mm. The surface roughens if the particle size conversely exceeds 1mm and, therefore, the particle size is limited to 0.1 to 1mm. The sound absorbent is formed by press molding the ceramic particles with which an org. or inorg. adhesive is mixed, by which the desired percentage of voids and strength of adhesion are obtd.

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, and more particularly to a sound absorbing material applied to general sound absorbing materials such as houses and buildings and sound insulating walls for roads and tunnels.

[0002]

2. Description of the Related Art A porous layer composed of particles or a fiber layer is used as a sound absorbing material because the internal porosity can be controlled relatively easily. In particular, the sound absorbing material using ceramic particles has the feature that it can be color-coordinated when it is made into a panel by coloring the particles themselves with pigments, and it can be used as a sound absorbing material that also serves as an interior material and as a sound insulation wall for landscape-oriented roads. Is coming.

There are several methods for producing this type of sound absorbing material depending on the application, but basically, a preformed product by pressing or rolling is dried in the next step or sintered at a high temperature. There are two ways.

[0004]

In the case of high temperature sintering, there is no problem because the fixing strength within the particles is developed by sintering, but in the case of a dry type at room temperature that does not result in sintering, the specific gravity is 0.1. Although a method of backing with a foamed aluminum of a certain degree (see Japanese Patent Application Laid-Open No. 02-120799) has been put to practical use, all of them have a reinforcing material, so that there is a problem in the difference in expansion coefficient due to different materials and the problem of corrosion.

In view of the above technical level, the present invention is to provide a sound absorbing material which does not have the above-mentioned problems.

[0006]

Therefore, the present invention is characterized in that the ceramic particle layer pressure-molded together with the adhesive has a particle size of 0.1 to 1 mm and a porosity of 30 to 45% by volume.

[0007]

The operation of the present invention will be described. In the sound absorbing material, the air gap serves to absorb the energy of the incident sound, but if the porosity is less than 30%, the sound reflection function becomes too large, and the sound absorption coefficient lowers. If it exceeds, the sound transmission becomes large, so it is limited to 30 to 45%.

The particle size of the ceramic particles is 0.1.
If it is less than mm, the sound absorbing performance is deteriorated due to the clogging of voids.
If it exceeds mm, the surface becomes rough, so it is limited to 0.1 to 1 mm.

A desired porosity and adhesive strength can be obtained by pressure-molding ceramic particles mixed with an organic or inorganic adhesive to produce such a sound absorbing material. In order to make the above ceramic particles have the above porosity, it is extremely desirable to pressurize at 80 to 400 ton / m ² .

With the above structure, a desired sound absorption coefficient and adhesive strength can be obtained, and a reinforcing material such as a conventional sound absorbing material is almost unnecessary.

[0011]

EXAMPLES Examples of the present invention will be described below based on experimental data. The materials used in the experiment are as follows.

As the ceramic particles, mullite crushed particles having a particle size distribution of 0.1 to 1 mm 300 g Liquid epoxy resin adhesive 10 g Here, the addition amount of the epoxy resin adhesive is less than 3% as a result of the preliminary test. After confirming that the adhesive strength is sufficient, the addition amount of 10 g was set.

Next, a floor plate is set in a press die of 300 mm × 300 mm, and a mixture of the above materials well is filled on the bottom plate in about 3 layers to a thickness of 3 mm. In addition, 80
Pressure molding is performed at a pressure of ton / cm ² . Then, the molded product was taken out from the press mold and naturally dried for 3 days indoors. At this time, when the molded product is taken out of the mold immediately after pressing, in the case of ceramic particles of ceramics alone, by laying the floor plate on the die under the press, it is possible to take out the ceramic molded product without breaking the floor plate at all. Became.

The size of the product after natural drying is 300 mm × 3
The thickness was 00 mm, the thickness was about 3 mm, and there was no particle loss, and it was confirmed that the ceramic particles were uniformly filled on both the surface and the cross section and were in close contact with each other. The porosity of this product was measured and found to be 38%. Almost no change in thickness due to product, 3 ± 0.1 m
Since it was within m, it was not possible with the conventional product due to the thickness of the backup material (foam, etc.), but in this example there is sufficient adhesive strength between the ceramic particles and the backup material can be removed. , Ultra-thin products have become possible.

Further, in order to check the sound absorbing performance of the sound absorbing material of this example, a test was carried out according to the method of measuring the sound absorption coefficient of the reverberation chamber according to JIS A 1909-1967. The results are shown in FIG. 1, in which the symbol ◯ indicates the present example, and the symbol x indicates the conventional glass wool having a thickness of 10 mm as a comparative material. From the figure, it can be seen that although this example is thin, it exhibits a sound absorption coefficient over that of conventional glass wool over all frequencies.

[0016]

EFFECTS OF THE INVENTION The sound absorbing material of ceramic particles molded by pressing can be easily taken out of the mold immediately after pressing by laying a floor plate alone. Moreover, the product size of the final product can be arbitrarily molded, and in particular, the thickness can be freely made from extremely thin to extremely thick.

Further, since the ceramic is a simple substance,
Since there is no deformation due to the difference in the expansion coefficient due to the equipment and no reinforcement is required, there is no corrosion due to the reinforcement and the weight of the product can be reduced.

Further, the sound absorbing performance is stable and good because there is almost no change in the sound absorbing performance due to the ceramic alone.

[Brief description of drawings]

FIG. 1 is a chart showing sound absorbing characteristics of a sound absorbing material according to an embodiment of the present invention.

Claims (1)

[Claims] 1. A ceramic particle layer pressure-molded together with an adhesive having a particle size of 0.1 to 1.0 mm and a porosity of 30 to 4
A sound absorbing material characterized by being 5% by volume.