PURPOSE: To obtain readily the title pitch without any increase in the softening point by converting to pitch an extract obtd. by extracting a member selected from coal tar, tar pitch and a petroleum-based thermal cracking oil with an aliph. solvent.
CONSTITUTION: 1 pt.wt. coal tar, tar pitch or a petroleum-based thermal cracking oil is mixed with at least 1 pt.wt. solvent comprising 70-100wt.% aliph. solvent of the formula CnH2n+2 or CnH2n (wherein n is 4-9) and not contg. any arom. solvent, and extraction is performed at a temp. of from room temp. to b.p. of the solvent for 0.5-24hr. After the extraction, the extract is separated into solvent solubles and solvent insolubles. The solvent solubles are evaporated or distilled under reduced or atmospheric pressure to remove the solvent. The solvent solubles freed of the solvent are distilled or thermally reformed at 360-400°C to thereby obtain a pitch.
SUGIBE HIDETAKA
TAJIMA YOICHI
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