| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a dihydroxydiphenyl sulfone which suppresses the generation of a texture fog significantly or almost to a zero level, when used as a thermosensitive recording material and has the content of 90 wt% or more of a 2,4'-dihydroxydiphenyl sulfone. <P>SOLUTION: In this method for manufacturing the dihydroxydiphenyl sulfone, a mixture of (1) a crude dihydroxydiphenyl sulfone of 90 wt% or more of its pure content but containing a phenolsulfonic acid phenyl ester as an impurity; (2) 0.02 to 0.4 equivalent of an alkaline material based on the dihydroxydiphenyl sulfone contained in its crude one; and (3) an aqueous solvent is thermally stirred and cooled at 40 to 70 °C. Finally the deposited crystal is separated. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
