| 摘要 |
PURPOSE:To obtain the titled laminated sheet excellent in punching quality, heat resistance, etc., by molding bases impregnated with a thermosetting resin varnish containing a reaction product obtained from a phosphate ester and a phenolic novolak resin. CONSTITUTION:A phosphate of formula I (wherein R1-3 are each alkyl or aryl) is mixed with a phenolic novolak resin of an average MW of 300-1,500 so that the content of skeletons substituted with the phosphate per molecule may be within 90%, and the obtained mixture is subjected to a transesterification reaction at 100-250 deg.C in the presence of 0.001-2wt% catalyst to obtain a flame retardant comprising a reaction product in which part of the phenol skeletons of the novolak resin contain a phosphate of formula II (wherein R4 is H, alkyl or methylol). Next, bases such as paper or synthetic fiber cloth are impregnated with a thermosetting resin varnish containing the flame retardant, and at least two of these bases are luminated and molded. |
