| 摘要 |
The invention relates to stilbene derivatives which are used as optical brightening agents, particularly as anionic brightening agents for polyamide and cellulosic substrates. These stilbene derivatives have the formula I <IMAGE> I in which both X's are the same and are CR5 or N, where R5 is hydrogen, C1-4alkyl or phenyl; both Y's are the same and are each one of the radicals of benzofuran, triazole, pyrazole, dibenzofuran or dibenzothiophene and benzothiophene, and R1 is as defined in the specification.
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