Sound insulation material

Abstract

To provide a sound insulation material having excellent sound insulation performance and strength.SOLUTION: A sound insulation material comprises: a first porous structure consisting of diatomaceous earth; and a second porous structure consisting of the diatomaceous earth, which has smaller pores and is denser than the first porous structure.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a sound insulating material comprising diatomaceous earth. [Background technology]

[0002] Conventionally, diatomaceous earth has been molded and used for bath mats, etc. In recent years, the use of mesopore diatomaceous earth, also known as Wakkanai diatomaceous earth, has been developed, and it is used, for example, as a building material such as a wall material.

[0003] In recent years, research has been progressing on soundproofing materials with even more specialized porous structures (Patent Document 1). However, few conventional diatomaceous earth products are able to achieve both soundproofing performance and strength, and there are no diatomaceous earth products that are particularly excellent in both soundproofing performance and strength, and conventional diatomaceous earth products are still not satisfactory. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2023-173401 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a sound-insulating material having excellent sound-insulating performance and strength. [Means for solving the problem]

[0006] As a result of extensive research into achieving the above-mentioned object, the present inventors have found that a structure including a first layer having a porous structure made of diatomaceous earth, with a second layer made of the same diatomaceous earth and having a dense porous structure formed on top of the first layer, the second layer having a smaller pore size and a denser porous structure than the first layer, not only has excellent sound insulation performance but also has excellent strength, and that such a structure is useful as a sound insulation material and can solve all of the above-mentioned conventional problems at once. Furthermore, after obtaining the above findings, the inventors of the present invention conducted further studies and completed the present invention.

[0007] That is, the present invention relates to the following inventions. [1] A sound-proofing material comprising a first porous structure made of diatomaceous earth, characterized in that the sound-proofing material further comprises a second porous structure made of the diatomaceous earth, the second porous structure having a smaller diameter and being denser than the first porous structure. [2] The sound-proofing material according to [1], wherein the pore sizes of the porous structures are different and a third porous structure made of the diatomaceous earth is further formed. [3] The sound-proofing material according to [1], wherein the diatomaceous earth is Wakkanai diatomaceous earth. [4] The sound-insulating material according to [1], wherein the porosity of the first porous structure is 50% or more, and the porosity of the second porous structure is 10% or less. [5] The sound-proofing material according to [1], wherein the porous structures are all made of fired bodies. [6] A method for producing a sound-insulating material using a slurry containing diatomaceous earth powder, characterized in that a combustible substance is used to form a first layer having a porous structure made of the diatomaceous earth and a second layer made of the diatomaceous earth and having a dense porous structure in which the pore size of the porous structure is smaller and the second layer is denser than that of the first layer. [7] The manufacturing method according to [6], wherein the combustible material is a polymer. [8] The manufacturing method according to [6], wherein the slurry is placed in a mold having a removable inner frame and then fired to form the first layer and the second layer. [Effects of the Invention]

[0008] The sound-insulating material of the present invention has excellent sound-insulating properties and exhibits the effect of being excellent in strength. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 shows a mold having a plurality of removable inner frames used in Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0010] The sound-proofing material of the present invention is a structure including a first layer having a porous structure (first porous structure) made of diatomaceous earth, and is characterized in that a second layer made of the diatomaceous earth and having a dense porous structure (second porous structure) in which the pore size of the porous structure is smaller and the structure is denser than that of the first layer is provided on the first layer.

[0011] The porous structure is not particularly limited in terms of pore size, etc., and any known porous structure may be used. In the present invention, it is preferable that the pore sizes of the porous structures are different and that a third layer (third porous structure) made of diatomaceous earth is further provided. In the present invention, it is also preferable that the diatomaceous earth is Wakkanai diatomaceous earth. In the present invention, it is also preferable that the porosity of the first layer is 50% or more and the porosity of the second layer is 10% or less. Within these preferred ranges, the absorbency and strength derived from the porous structure can be improved.

[0012] In the present invention, it is preferable that the structure is a fired body, and such a preferred structure can be easily obtained by a method for manufacturing a structure using a slurry containing diatomaceous earth powder, in which a combustible substance is used to form a first layer having a porous structure made of diatomaceous earth and a second layer made of diatomaceous earth and having a dense porous structure in which the pore size of the porous structure is smaller and the second layer is denser than the first layer.

[0013] In the present invention, the combustible material is preferably a polymer. This preferred range allows for easier formation of the structure by firing. Furthermore, in the present invention, the first layer and the second layer are preferably formed by placing the slurry in a mold having a removable inner frame and firing the mixture. The slurry is not particularly limited as long as it does not impair the present invention, but it preferably contains a binder in addition to the diatomaceous earth. Suitable examples of the binder include a mixture of Kibushi clay, silicic anhydride, and an appropriate amount of water, or rhyolitic natural glass powder added to Wakkanai diatomaceous earth. When using such a preferred binder, the slurry is preferably prepared by blending and kneading, for example, 10 parts diatomaceous earth with 1 to 3 parts by weight, preferably 2 parts by weight, Kibushi clay, 1 to 3 parts by weight, preferably 1 part by weight, silicic anhydride, and an appropriate amount of water, or 1 to 3 parts by weight, preferably 1 part by weight, of rhyolitic natural glass powder.

[0014] In the present invention, the structure is used as a sound insulating material either as it is or after processing. [Example]

[0015] Example 1 1. Preparation of slurry A slurry was prepared by mixing 10 parts by weight of diatomaceous earth, 2 parts by weight of Kibushi clay, 1 part by weight of silicic anhydride, an appropriate amount of water, and 1 part by weight of rhyolitic natural glass powder with combustible materials. The slurry was placed in the mold shown in Figure 1 with the following combustible material amounts, and fired.

[0016] [Combined amount of flammable materials] Area 1: Slurry containing 0% by weight of combustible material (polymer) Area 2: Slurry of 10% by weight of combustible material (polymer) Area 3: Slurry of 20% by weight of combustible material (polymer) Area 4: Slurry containing 30% by weight of combustible material (polymer) Zone 5: Slurry of 40% by weight of combustible material (polymer)

[0017] The firing conditions were that the temperature inside the firing kiln was raised to around 1100°C and maintained for approximately 2 hours, after which the temperature increase was stopped and the product was slowly cooled in the firing kiln and removed. The porosity (air void ratio) of regions 1 to 5 of the resulting fired body (structure) was examined, and it was found to be 10% for region 1, 20% for region 2, 30% for region 3, 40% for region 4, and 50% for region 5.

[0018] (Test Example 1) The structure (specimen) obtained in Example 1 was left to stand under conditions of 20°C and 50% RH humidity until it reached a constant weight, and the bulk density was measured. Seven specimens were used for each sample, and the average of the measured values ​​was obtained. In addition, the bending strength of some of the specimens was measured by a three-point bending test. As a comparative example, the bending strength of a structure consisting of only region 1 was measured. The bending strength of the comparative example was 2.8 Nmm -2 The bending strength of the structure of Example 1 was 3.5 Nmm-2.

[0019] (Test Example 2) Floor impact sound measurements were made by applying impact vibrations to the floor on the upper floor using a standard impact source and measuring the sound pressure level in the room below. There are two types of floor impact sound: "light floor impact sound," such as the sound of hard, light objects falling, and "heavy floor impact sound," such as jumping, and standard impact sources for measuring floor impact sound were used for each.

[0020] With the example product, the impact noise was audible from a distance and was rated at ΔLL-5. With the comparative example product, the impact noise was audible but not bothersome and was rated at ΔLL-4. The comparative example product had inferior sound insulation performance compared to the example product. [Industrial Applicability]

[0021] The structure of the present invention is suitable for use as a sound insulating material. [Explanation of symbols]

[0022] 1 area 1 2 area 2 3 area 3 4 area 4 5 areas 5

Claims

1. A sound-proofing material comprising a first porous structure made of diatomaceous earth, characterized in that the sound-proofing material further comprises a second porous structure made of the diatomaceous earth, the second porous structure having a smaller diameter and being denser than the first porous structure.

2. 2. The sound-insulating material according to claim 1, wherein the pore sizes of the porous structures are different from each other and a third porous structure made of the diatomaceous earth is further formed.

3. 2. The sound-insulating material according to claim 1, wherein the diatomaceous earth is Wakkanai diatomaceous earth.

4. 2. The sound-insulating material according to claim 1, wherein the porosity of the first porous structure is 50% or more, and the porosity of the second porous structure is 10% or less.

5. 2. The sound-insulating material according to claim 1, wherein each of said porous structures is made of a sintered body.

6. A method for producing a sound-insulating material using a slurry containing diatomaceous earth powder, comprising using a combustible substance to form a first layer having a porous structure made of diatomaceous earth and a second layer having a dense porous structure made of diatomaceous earth, the second layer having a smaller pore size and a denser porous structure than the first layer.

7. 7. The method of claim 6, wherein the combustible material is a polymer.

8. 7. The method according to claim 6, wherein the slurry is placed in a mold having a removable inner frame and then fired to form the first layer and the second layer.

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