LIQUID CRYSTAL MEDIUM, METHOD FOR THE STABILISATION THEREOF AND LIQUID CRYSTAL DISPLAY

• Main Authors: Fortte, Rocco, Goebel, Mark, Pauluth, Detlef, Baron, Eveline
• Format: Patent
• Language: English; French; German
• Published: 14.10.2020
• Subjects: ADHESIVES; CHEMISTRY; DYES; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FORELSEWHERE; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; NATURAL RESINS; PAINTS; POLISHES; TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHICCOMMUNICATION

Liquid crystalline medium comprises (a) at least one substituted piperidine derivative (I) excluding substituted carbonic acid dipiperidin-4-yl ester compounds (Ia), and (b) at least one substituted 1-cyclohexylmethoxy-2,3-difluoro-benzene derivative (II). Liquid crystalline medium comprises (a) at least one substituted piperidine derivative of formula (I) excluding substituted carbonic acid dipiperidin-4-yl ester compounds of formula (Ia), and (b) at least one substituted 1-cyclohexylmethoxy-2,3-difluoro-benzene derivative of formula (II). n : 1-4; m : 4-n; Z1 : organic group having 4 binding sites; Z11, Z12 : -O-, -(C=O)-, -(N-R14)- or single bond, where Z11 and Z12 do not simultaneously represent -O-; r, s : 0 or 1; either Y11-Y14 : 1-4C alkyl; or Y11+Y12, Y13+Y14 : 3-6C divalent group; R11 : O-R13, oxygen free radical or OH, preferably O-R13, preferably isopropyloxy, cyclohexyloxy, acetophenyl-oxy or benzyloxy, or oxygen free radical (preferred); R12 : H, F, OR14, NR14R15, 1-20C alkyl (in which 1 CH 2 group or several CH 2 groups are optionally replaced by -O- or -C(=O)-, where two adjacent CH 2 groups are not optionally replaced by -O-), hydrocarbyl, preferably cycloalkyl or alkyl-cycloalkyl (in which 1 CH 2 group or several CH 2 groups are optionally replaced by -O- or -C(=O)-, where 2 adjacent CH 2 groups are not optionally replaced by -O-, and 1 H or several H are optionally replaced by OR14, N(R14)(R15) or R16) or (hetero)aromatic hydrocarbyl (in which 1 H or several H are optionally replaced by OR14, N(R14)(R15) or R16); R13 : 1-20C alkyl (in which 1 CH 2 group or several CH 2 groups are optionally replaced by -O- or -C(=O)-, where two adjacent CH 2 groups are not optionally replaced by -O-), hydrocarbyl, preferably cycloalkyl or alkyl-cycloalkyl (in which 1 CH 2 group or several CH 2 groups are optionally replaced by -O- or -C(=O)-, where 2 adjacent CH 2 groups are not optionally replaced by -O-, and 1 H or several H are optionally replaced by OR14, N(R14)(R15) or R16), (hetero)aromatic hydrocarbyl (in which 1 H or several H are optionally replaced by OR14, N(R14)(R15) or R16), 1,4-cyclohexylene (in which at least one CH 2 group is optionally replaced by -O-, -CO- or -NR14-) or acetophenyl, isopropyl or 3-heptyl; R14, R15 : 1-10C alkyl, 1-10C acyl, aromatic 6-12C hydrocarbyl or 6-12C carboxylic acid; R16 : 1-10C alkyl (in which 1 CH 2 group or several CH 2 groups are optionally replaced by -O- or -C(=O)-, where 2 adjacent CH 2 groups are not optionally replaced by -O-); G : oxygen free radical; G1 : 1-4C alkyl; R41 : unsubstituted 1-7C alkenyl; R42 : 1-7C alkyl, 1-6C alkoxy or 2-6C alkenyloxy (all unsubstituted); and i : 0 or 1. Provided that when n is 1, R11 is oxygen free radical and -[Z11] r-[Z12] s is -O-, -(CO)-O-, -O-(CO)-, -O-(CO)-O-, -NR14- or -NR14-(CO)-, then [R12] m-Z1 is not 1-10C alkyl, cycloalkyl, cycloalkylalkyl or alkyl-cycloalkyl (in all groups at least one CH 2 group is optionally replaced by -O- such that two O atoms are not directly bonded with each other); and when n is 2 and R11 is O-R13, then R13 is not nitrogen-1-9C alkyl. Independent claims are also included for: (1) an electro-optical display or an electro-optical component comprising the above liquid crystalline medium; (2) preparing the liquid crystalline medium, comprising mixing (I) with (II), substituted bicyclohexyl compounds of formula (IVb) and/or substituted 1-cyclohexyl-2,3-difluorobenzene derivatives of formula (IIIa), substituted 1-cyclohex-1-enyl-2,3-difluorobenzene derivatives of formula (IIIb), substituted 2,3-difluoro-biphenyl derivatives of formula (IIIc) or substituted 2',3'-difluoro-[1,1';4',1'']terphenyl compounds of formula (IIId); and (3) stabilizing the liquid crystalline medium, comprising adding a medium which comprises (I) and optionally 2,6-di-tert-butyl-4-(4-propyl-cyclohexyl)-phenol, 2,6-di-tert-butyl-4-(5-propyl-[1,3]dioxan-2-yl)-phenol, 3,5-di-tert-butyl-4-hydroxy-benzoic acid hexadecyl ester, 3,5-di-tert-butyl-4-hydroxy-benzoic acid 4-pentyl-cyclohexylmethyl ester, 2,5-bis-(1,1,3,3-tetramethyl-butyl)-benzene-1,4-diol and acrylic acid 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methyl-benzyl)-4-methyl-phenyl ester to a medium which comprises (II). R31 : unsubstituted 1-7C alkyl; R32 : 1-7C alkyl or 1-6C alkoxy (both unsubstituted); m, n, o : 0 or 1; R51 : 1-7C alkyl or 2-7C alkenyl (both unsubstituted); and R52 : unsubstituted 2-7C alkenyl. [Image] [Image] [Image].