To obtain a phenol hydroxy group-remaining type phosphoric ester, a flame retardant epoxy resin composition consisting essentially of the phosphoric ester and a laminated sheet prepared by thermosetting the resin composition.
This phenol hydroxy group-remaining type phosphoric ester is obtained by reacting bisphenols with a phosphorus oxyhalide and represented by the general formula 1 [wherein, R1 is hydrogen, a lower alkyl, an aryl or an aralkyl group; A is an alkylene group such as CH2 or C(CH3)2, O, S, SO2 or a single bond; and x denotes an integer of 0-4]. Furthermore, the phenol hydroxy group-remaining type phosphoric ester is prepared by reacting the bisphenols with the phosphorus oxyhaldide in a molar ratio of the phosphorus oxyhalide of 0.1-0.5 to the bisphenols.
YAMAZAKI KATSUTOSHI
YOKOYAMA JUN
HIRAMATSU MASAO
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