| 摘要 |
PURPOSE:To obtain a phenolic resin foam having excellent elasticity, heat resistance etc., by adding a highly water-absorbing powder during the course of mixing a blowing agent, foam stabilizer, a hardener, etc. with a liquid resol type phenolic resin precondensate, and then expanding the mixture. CONSTITUTION:A phenol such as phenol or resorcinol is reacted with an aldehyde such as formaldehyde in the presence of an alkaline catalyst. A power of a highly water-abosrbing material such as an acrylic acid/vinyl alcohol copolymer or caboxymethylcellulose is added during the course of mixing a blowing agent, e.g. Freon, a surfactant, a foam stabilizer, e.g. Tween, an acidic hardener, e.g. p-toluenesulfonic acid, etc. with the above liquid resol type phenolic resin precondensate. The mixture is placed in a mold and expanded by heating to obtain the desired phenolic resin foam. |
