Crystal modification of disazo pigment derived from 1,4-bis(acetoacetylamino)-2,5-dimethylbenzene amp; methyl 2-amino-4-N-substituted-aminocarbonylbenzoate

摘要

The pigment is preferably, characterized by its x-ray diffraction pattern which exhibits two strong peaks corresponding to Ò 0.2 two theta double glancing angles of 7.9 and 25.7, four medium strength peaks corresponding to Ò 0.2 two theta double glancing angles of 5.2, 12.3, 12.8 and 18.6 and eight relatively weak peaks corresponding to Ò 0.2 two theta double glancing angles of 6.8, 10.7, 14.0, 15.7, 17.2, 21.1, 23.1 and 28.3. (see figure 2). The beta form crystal modification is obtained by treating the amorphous form of the pigment with N-methyl pyrrolidone, eg at 80{ - 160{C for 2-10 hours. The pigment may be used to colour a high molecular weight organic material.