| 摘要 |
PCT No. PCT/JP97/00921 Sec. 371 Date Dec. 11, 1997 Sec. 102(e) Date Dec. 11, 1997 PCT Filed Mar. 19, 1997 PCT Pub. No. WO97/34955 PCT Pub. Date Sep. 25, 1997This invention related to a novel beta -crystal of the compound represented by the following formula (1), which is useful as a dyestuff. The beta -crystal of this invention is characterized by being stable in high temperature and having sharp peaks in the powder X-ray diffractometory. This invention is related to a process for producing a said beta -crystal, said process comprising heating a known thermally unstable alpha -crystal at a temperature higher than 15 DEG C., preferably higher than 40 DEG C. in water, a water-soluble organic solvent, or a solvent comprising water containing an anionic or nonionic surface active agent. Furthermore, this invention is related to a dyestuff composition containing of the said beta -crystal, and a process for dyeing comprising employing the said beta -crystal.
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