| 摘要 |
Impregnated paper sheets are produced by impregnating with water or a soln. of a water soluble phenolic resin, immediately impregnating the wetted sheet with a mixt. of an epoxy resin and a crosslinking agent which is added to the resin a sufficient time before impregnation to partly cure the resin, and a water soluble phenolic resin, and drying the impregnated sheet. Used for the prodn. of laminates with good electrical and mechanical properties. An intermediate drying stage is eliminated, and the paper is uniformly impregnated. Reaction of the crosslinking agent with water is avoided by allowing the agent to act on the epoxy resin before impregnation. |
