| 摘要 |
A fluorescent brightener is proposed which consists of 51-99% of an unsymmetrically substituted compound of the formula <IMAGE> (1) in which R and R1 are identical or different and, if R and R1 are identical, R1 must occupy a position in the phenyl ring to which it is bonded which differs from the position occupied by R in its phenyl ring, and in which R and R1 independently of one another are CN or a carboxylic acid ester group, and 49-1% of a symmetrically substituted compound of the formula <IMAGE> (2) in which R is as defined above and the two R's are bonded to identical positions in their phenyl rings, as are also agents which contain these fluorescent brighteners and the use of these fluorescent brighteners for the fluorescent brightening of, in particular, textile materials, preferably made of polymer. The said fluorescent brighteners are prepared by reacting terephthalaldehyde preferably with a correspondingly substituted benzylphosphonate and further reacting the resulting mixture of a correspondingly substituted 4-stilbene aldehyde and a symmetrical p-bis-styrylbenzene with a benzylphosphonate which differs from the benzylphosphonate first used. |
