| 摘要 |
PROBLEM TO BE SOLVED: To obtain a sound absorbing material remarkably improved in sound absorption coefficient in a medium and low frequency region by forming a fibrous material and a whisker granular assembly into a porous formed product by actions of a binder. SOLUTION: This sound absorbing material is obtained by mutually joining whiskers having <=2μm diameter such as aluminum borate in a fibrous material such as ceramic fibers and the whiskers into a granular assembly having 50-1000μm grain diameter without using a binder. This porous boardlike sound absorbing material is prepared by mixing the granular assembly with a binder such as an acrylic acid emulsion in water, then adding a gelling agent such as ammonium sulfate thereto, further adding a polyacrylamine-based flocculant to the resultant mixture, flocculating the slurry, casting the flocculated slurry into a prescribed forming mold, then carrying out the press compressing and dehydrating treatments and subsequently drying the resultant material by heating.
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