| 摘要 |
The dye in the mixture has the general formula <IMAGE> in which R<1>, R<3>, R<4> and R<6> are H, OH, OCH3, NH2, NHCH3, N(CH3)2 or NO2, R<2> and R<5> are in the 2- or 7-position, are identical or different and have the formula <IMAGE> in which X is an unsaturated, in particular 2- or 3-membered bridge and R<7> is H, alkyl, cycloalkyl, alkoxy, alkylthio, amino, alkylamino, dialkylamino, halogen or cyano. Dyes of this type are chemically resistant, soluble in liquid crystals and are distinguished by a particularly high dichroic ratio. They are therefore particularly suitable as colour additives for liquid-crystal displays operating on the guest-host effect. <IMAGE>
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