| 摘要 |
PURPOSE:To obtain a high rigid and high internal-loss speaker constitution body having high temperature resistant characteristics, by forming the speaker constitution body by using a kneaded material consisting essentially of polypropylene and flake graphite powder. CONSTITUTION:A speaker consitution body is made of a kneaded body of a single component of polypropylene or a mixture of said component and polymethylmethacrylate and a mixed material, obtained by mixing a rubbery material, such as acrylonitrile butadiene rubber NBR, in said synthetic resin as required, and flake graphite powder. The flake graphite powder is oriented along the surface of the constitution body and preferably has a mean grain size of about 20mum or below. With regrad to the ratio of compounding the graphite powder and resin, the modulus of elasticity is improved, for example, when 10-90wt% graphite powder and 90- 10wt% resin are used; the modability is not spoiled and no embrittlement of moldings occurs. The compounding ratio of PMMA and polypropylene is determined freely. Then, the 2-50wt% rubbery material is added to the resin; when about 10wt% material is added, the modulus of elasticity decreases by about 20%, but the internal loss is improved about 1.5-2 times. |
