| 摘要 |
PROBLEM TO BE SOLVED: To obtain a pigment excellent in heat resistance by dissolving a crude isoindolinone pigment in sulfuric acid and pouring the resultant soln. into water to cause precipitation. SOLUTION: 100 pts.wt. crude isoindolinone pigment is dissolved in about 300-5,000 pts.wt. pref. 500-2,000 pts.wt., sulfuric acid having a concn. of about 70-100wt.%, pref. about 95-98wt.%. The resultant soln. is slowly added to about 300-5,000 pts.wt., pref. about 700-2,500 pts.wt., water in a crystallization vessel while the temp. of the water is kept at about 20-50 deg.C under cooling and stirring, thus being diluted and caused to precipitate. Thus obtd. pigment slurry is filtered, washed with water until it becomes neutral to give a wet cake, dried, and ground, thus giving an isoindolinone pigment such as C.I.Pigment Yellow-110. |
