| abstract |
Title cpds. used as optical brightening agents for polyamides, polystyrene, polyvinyl chloride, polyacrylonitrile or cellulose esters are of formula: (in which R1 and R2 are the same or different, 5-18C alkyls, 2-20C substd. alkyls, or 3-4 alkenyls, X1 and X2 are the same or different, H,1-4C alkoxy, halogen, 3-4C alkenyl or 1-4C alkyl; Y1 and Y2 are the same or different and denote H, halogen, 3-4C alkenyl or 1-4C alkyl; a is H, halogen, 1-4C alkoxy or 1-4C alkyl; with the proviso that p-positions are free of alkoxy gps. or R1O and R2O gps.). |