LIQUID CRYSTAL DIELECTRICS, NEW DYESTUFFS USEFUL THEREIN, PROCESSES FOR THEIR PREPARATION, AND ELECTROOPTICAL DISPLAY ELEMENTS BASED THEREON

摘要

"LIQUID CRYSTAL DIELECTRICS, NEW DYESTUFFS USEFUL THEREIN, PROCESSES FOR THEIR PREPARATION, AND ELECTROOPTICAL DISPLAY ELEMENTS BASED THEREON" A new liquid crystal dielectric contains at least one dyestuff of formula I < IMG > X wherein R1 and R2 are identical or different and each is alkyl or alkoxy each of 3 to 8 C atoms or a group Z-Y-, or one of R1 and R2 can also be hydrogen, methyl, ethyl, methoxy or ethoxy; Z is R-Ph-, R-Ph-Ph-, R-Cy-, R-Cy-Cy-, R-Cy-Ph- or R-Ph-Cy-; Ph is 1,4-phenylene; Cy is 1,4-cyclohexylene; Y is -CH2-, -O-, -S-, -NH-, -CH2CH2-, -CH2-O-, -CH2-S-, -CH2-NH- or a direct bond; and R is hydrogen or alkyl or alkoxy, each of 1-8 C atoms.