| 摘要 |
PROBLEM TO BE SOLVED: To decrease a particle diameter and improve rheological properties and transparency by treating melt quinacridone obtained by heating (non) substituted 2,5-diarylamino-3,6-dihydroterephthalic acid and polyphosphoric acid with concentrated sulfuric acid. SOLUTION: Melt quinacridone is obtained by heating 1 pt. wt. of non- substituted and/or substituted 2,5-diarylamino-3,6-dihydroterephthalic acid and 3-10 pts.wt. of polyphosphoric acid at a temperature higher than 125 deg.C. The melt quinacridone is treated with 1-30 wt.% of concentrated sulfuric acid having concentration of 95-98 wt.% for 5-60 minutes followed by being immersed in 10-30 pts.wt. per unit weight of dihydroterephthalic acid of a liquid which does not dissolve quinacridone, by being recovered and dried to give linear quinacridones represented by formula (wherein A and B are each a substituent group selected from H, F, Cl, 1-3C alkyl and 1-3C alkoxy).
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