| 摘要 |
PROBLEM TO BE SOLVED: To make a product using paper fiber as a principal material thin in wall thickness and excellent in high rigidity, homogeneousness and surface smoothness. SOLUTION: Water of 50 pts is added to a blended material wherein coniferous tree pulp of 60 pts and a bonding agent comprising starch of 28 pts and polyvinyl alcohol of 12 pts are blended, and mixed. Zinc stearate of 1 pt is added to the mixture of 100 pts and kneaded to make a molding material. The molding material is held at 180 deg.C mold temperature, filled into a mold cavity having a smoothly-worked wall surface and molded. Thereby, a conical speaker having a homogeneous and smooth surface of a thin wall thickness and high rigidity and equipped with an oscillation property excellent in the quality of sound, is obtained.
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