| abstract |
Fluorescent bis-stilbene compds. for use as optical brighteners have formula (I). R1 - CH = CH - X - CH = CH - R2 X = a diphenyl group linked at the 4 and 4' positions with the CH group; and R1 and R2 = each monocyclic benzene groups, diphenyl groups or naphthalene groups; and at least one of the rings X, R1 and R2 is substd. by sulphonic acid, sulphone, carboxylic acid, nitrile, hydroxyl, mercapto or methyl. (I) are useful optical bighteners for treating org. materials, including synthetic polymers and fibres. |