| abstract |
Mixtures of fluorescent whitening agents consisting of 51 to 99% by weight of 1-(4-cyanostyryl)-4-(3'-styryl)benzene, 49 to 1% by weight of 1-(4-cyanostyryl)-4-(2'-cyanostyryl)benzene and 0.5 to 5% by weight of 1,4-bis(cyanostyryl)benzene, a process for the preparation of said mixtures by condensing terephthalaldehyde with a 4-dialkylphosphonomethylbenzonitrile to 4-cyano-4'-formylstilbene, which is further condensed, either direct or after isolation, with a 3- and 2-dialkylphosphonomethylbenzonitrile, the use of these mixtures for whitening polyester fibres, and compositions containing said mixtures for whitening polyester fibres. |