| 摘要 |
PURPOSE:To avoid the change in a minimum resonance frequency and frequency characteristics, by using a modified phenol resin, chemically bonded and unified phenol and polybutadiene as forming agent. CONSTITUTION:Isoprophenyl phenol or olygomer of isopropenyl phenol or their mixture and polybutadiene are reacted under the presence of acid catalyst. Further, they are reacted with phenol under the presence of acid catalyst. This reaction product is reacted with formaldehyde as a portion of phenyl and the obtained modified phenol resin is used as forming agent. This forming agent is impregnated to a base cloth and formed into a specified shape. |
