Mitsui Chemicals Asahi Life Materials Co., Ltd.

Moriroku Chemicals Company, Ltd.

Asahi Kasei Kabushiki Kaisha

Yasuo Nakanishi

Eiji Shiota

Chie Okamura

Masaaki Nishio

Toshiyuki Niwa

Kazumi Danjo

Shinya Yamamuro

Shohei Sugimoto

Sakiko Kawamura

Takashi Komatsu

Kazufumi Kato

Rumina Obi

Provided are a non-woven cloth and a layered non-woven cloth that are preferred as a skin material for a composite sound-absorbing material, which has excellent moldability and exceptional shape stability, and with which it is possible to achieve an adequate sound-absorption effect even in thin low-weight regions.

Nonwoven fabric, layered nonwoven fabric comprising the nonwoven fabric, and composite sound-absorbing material using them as skin material

Provided is a composite sound-absorbing material that can exhibit sound absorption properties in a broad range of low frequencies, intermediate frequencies, and high frequencies even in a low-basis-weight region having low thickness. The composite sound-absorbing material according to the present invention is configured from two or more layers including a base material and a skin material, the skin material being positioned on the outermost layer, wherein the composite sound-absorbing material is characterized in that the ratio (skin material:base material) of the surface area (m/m) per unit area of the skin material and the surface area (m/m) per unit area of the base material is at least 1:5 and less than 1:40.

Composite sound-absorbing material

Disclosed is a method for producing a fine powder. Two or more kinds of original materials are suspended and liquefied inert gas to form two or more kinds of slurries wherein each slurry contains at least one or more different kinds of original materials. Granular dry ice grinding medium is put into the slurries. The slurries are individually stirred and the original materials are pulverized into submicron-sized or nano-sized particles in the liquefied inert gas. The slurries are thereafter mixed. The liquefied inert gas is vaporized and the granular dry ice is sublimated. A mixture of the particles of the two or more kinds of original materials is recovered.

Method for producing fine powder and the fine powder produced by the same

Disclosed is a manufacturing method for a fine powder exhibiting improved solubility, little impurity contamination, and a high recovery rate. Material to be ground and a grinding medium are suspended and stirred in a liquefied inert gas dispersion medium such as dried ice, and the material to be ground is made into a sub-micron or nano-sized fine powder. A uniform fine powder can be obtained when the material to be ground is a mixture having two or more components. Impurity contamination can be reduced by using granular dry ice as the grinding medium.

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Tokyo, Japan

Yasuo Nakanishi