New Azo Dyes of 1, 5, 6 or 7) - disulfonaftaleno azo - 2 - (1 '- 2' - amino - 8 - hydroxy ('3' or 4 '),6 - disulfonaftaleno) - 7 - (4 - (azo acid diahlopirimidin - or triazil - ilamino) - 2 - benzene sulfonic acid) and processes for their Preparation