| 摘要 |
PURPOSE:To form a diaphragm having high elasticity, low density and proper acoustic internal loss by coating a mixing material with an unfoamed particle to be foamed by heating and a polymer having an Si-O bond to a diaphragm base made of fiber member via a binder and heating the material. CONSTITUTION:For example, 90-100pts.wt. of a thermoplastic resin is mixed to 10-20pts.wt. of unfoamed particles such as vinylidenechloride together with 5-10pts.wt. of toluene, and 30-70wt% solution of polymer organic solvent having the Si-O bond is added and mixed to the mixture in the weight ratio of 2:1. After this solution is coated and impregnated to the diaphragm base obtained by manufacturing to sheets natural fibers or synthetic fibers, the unfoamed particles are foamed by heating so as to form an independent porrous layer 3 and a water-proof film 4 on the surface of the diaphragm base. |
