| 摘要 |
PURPOSE:To obtain the title structure which is inexpensive, free of dimensional changes, good in machinability and capable of high-speed machining by expanding and curing a phenolic resol, a blowing agent and a curing agent so as to obtain a foam of a specified bulk density and a specified water content. CONSTITUTION:A phenol is condensed with an aldehyde in a molar ratio of 1.1-1.8 in the presence of a catalyst, and the reaction mixture is neutralized and dehydrated in vacuo to obtain a phenolic resol (A) of a solids concentration of 60-90wt.% and a viscosity (at 25 deg.C) of 100-10000cPs. 100 pts.wt. said resol is mixed with 0.1-20 pts.wt. blowing agent desirably of an evaporation type (e.g. trichloromonofluoromethane), 0.1-30 pts.wt. curing agent (e.g. p- toluenesulfonic acid) and optionally a foam stabilizer, a filler, etc., and agitated, expanded and cured to obtain the title structure comprising a phenolic resin foam of a bulk density of 0.3-0.6g/cm<3> and a water content of 5-15wt.%. |
