Patent EP-2722380-A2 (EP)
Inventor: GOEBEL MARK
IPC: C09K19/54
Filed: 2013-10-16
Abstract: 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 cyclohexyl 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 cyclohexyl 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; R21 : unsubstituted 2-7C alkenyl; A2 : cyclohexane-1,4-diyl, benzene-1,4-diyl, 2-fluorobenzene-1,4-diyl or 2,3-difluorobenzene-1,4-diyl; either p, q : 0-2; or p+q : 1-3; and R22 : 1-7C alkyl, 1-6C alkoxy or 2-6C alkenyloxy (all unsubstituted). 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 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/or substituted bicyclohexyl compounds of formula (IV); 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, 1-6C alkoxy or 2-6C alkenyloxy (all unsubstituted); m, n, o : 0 or 1; R41 : 1-7C alkyl or 2-7C alkenyl (both unsubstituted); and R42 : 1-7C alkyl, 1-6C alkoxy or 2-7C alkenyl (all unsubstituted).