Liquid-crystalline medium
The invention relates to a liquid-crystalline medium based on a mixture of polar compounds which contains at least one compound of the formula I, and at least one additional compound, and to the use of the LC mixtures for an active- or passive matrix addressed displays, in particular based on the VA, PSA, PS-VA, IPS, FFS, PS-IPS, PS-FFS technology, preferably in optical displays for the self-aligning VA mode.
1. A liquid-crystalline medium comprising a mixture of polar compounds, including in said mixture
at least one compound of formula I,
in which
R 1 denotes an alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH 2 groups in these radicals may each be replaced, independently of one another, by —C≡C—, —CF 2 O—, —CH═CH—,
—O—, —CO—O—, —O—CO— in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by halogen,
L 1 , L 2 and L 3 each, independently of one another, denote H, F, Cl, CF 3 , CHF 2 or alkyl with 1-5 carbon atoms, preferably F or alkyl, and
m denotes 0, 1, 2, 3, 4, 5 or 6,
and
at least one compound of the formulae I-A, I-B, I-G OR I-J,
in which
R 1 * and R 2 each, independently of one another, denote an alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH 2 groups in these radicals may each be replaced, independently of one another, by —C≡C—, —CF 2 O—, —CH═CH—,
—O—, —CO—O—, —O—CO— in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by halogen,
a 0 or 1, and
L 1 and L 2 each, independently of one another, denote H, F, Cl, CF 3 or CHF 2 .
2. The liquid-crystalline medium according to claim 1 , comprising one or more compounds of formulae I-1 to I-36,
3. The liquid-crystalline medium according to claim 1 , comprising one or more compounds of formulae I-1a, I-2a or I-2b,
in which
alkyl denotes a straight-chain alkyl radical having 1 to 7 carbon atoms.
4. The liquid-crystalline medium according to claim 1 , comprising one or more compounds of formulae I-A-1 to I-K-1,
in which
alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms, and
alkoxy denotes a straight-chain alkoxy radical having 1-6 C atoms,
L 1 and L 2 each, independently of one another, denote H, F, Cl, CF 3 or CHF 2 .
5. The liquid-crystalline medium according to claim 1 , additionally comprising one or more compounds of the formulae IIA to IIC,
in which
R 2A , R 2B and R 2C each, independently of one another, denote H, an alkyl or alkenyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF 3 or at least monosubstituted by halogen, where, in addition, one or more CH 2 groups in these radicals may be replaced by —O—, —S—,
—C≡C—, —CF 2 O—, —OCF 2 —, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another,
L 1-4 each, independently of one another, denote F or Cl,
Z 2 and Z 2′ each, independently of one another, denote a single bond, —CH 2 CH 2 —, —CH═CH—, —CF 2 O—, —OCF 2 —, —CH 2 O—, —OCH 2 —, —COO—, —OCO—, —C 2 F 4 —, —CF═CF—, —CH═CHCH 2 O—,
p denotes 1 or 2,
q denotes 0 or 1, and
v denotes 1 to 6.
6. The liquid-crystalline medium according to claim 1 , additionally comprising one or more compounds of formula III,
in which
R 31 and R 32 each, independently of one another, denote a straight-chain alkyl, alkoxyalkyl, alkenyl, or alkoxy radical having up to 12 C atoms, and
and
Z 3 denotes a single bond, —CH 2 CH 2 —, —CH═CH—, —CF 2 O—, —OCF 2 —, —CH 2 O—, —OCH 2 —, —COO—, —OCO—, —C 2 F 4 —, —C 4 H 9 —, —CF═CF—.
7. The liquid-crystalline medium according to claim 1 , additionally comprising one or more compounds of the formulae L-1 to L-11,
in which
R, R 1 and R 2 each, independently of one another,
denote H, an alkyl or alkenyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF 3 or at least monosubstituted by halogen, where, in addition, one or more CH 2 groups in these radicals may be replaced by —O—, —S—,
—C≡C—, —CF 2 O—, —OCF 2 —, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another,
and alkyl denotes an alkyl radical having 1-6 C atoms, and
s denotes 1 or 2.
8. The liquid-crystalline medium according to claim 1 , additionally comprising one or more compounds of formulae T-1 to T-21,
in which
R denotes a straight-chain alkyl or alkoxy radical having 1-7 C atoms, and
m denotes 1-6.
9. The liquid-crystalline medium according to claim 1 , additionally comprising one or more compounds of formulae O-1 to O-11,
in which
R 1 and R 2 each, independently of one another, denote H, an alkyl or alkenyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF 3 or at least monosubstituted by halogen, where, in addition, one or more CH 2 groups in these radicals may be replaced by —O—, —S—,
—C≡C—, —CF 2 O—, —OCF 2 —, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another.
10. The liquid-crystalline medium according to claim 1 , wherein the mixture contains 0.01 to 10% by weight of the compound of the formula I based on the mixture as a whole.
11. The liquid-crystalline medium according to claim 1 additionally comprising one or more additives.
12. The liquid-crystalline medium according to claim 1 , comprising an additive that is an antioxidant, stabilizer, reactive mesogen, dopant, microparticle, nanoparticle or dyes.
13. The liquid-crystalline medium according to claim 1 , additionally comprising at least one stabilizer of the formula:
14. The liquid-crystalline medium according to claim 1 , additionally comprising at least one reactive mesogen of formulae M1 to M41,
in which the individual radicals have the following meanings:
P 1 , P 2 and P 3 each, independently of one another, denote a polymerizable group,
Sp 1 , Sp 2 and Sp 3 each, independently of one another, denote a single bond or a spacer group,
where, in addition, one or more of the radicals P 1 -Sp 1 -, P 2 —Sp 2 - and P 3 —Sp 3 - may denote R aa , with the proviso that at least one of the radicals P 1 —Sp 1 -, P 2 —Sp 2 - and P 3 -Sp 3 - present does not denote R aa ,
R aa denotes H, F, Cl, CN or straight-chain or branched alkyl having 1 to 25 C atoms, in which, in addition, one or more non-adjacent CH 2 groups may each be replaced, independently of one another, by C(R 0 )═C(R 00 )—, —C≡C—, —N(R 0 )—, —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O— in such a way that O and/or S atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by F, Cl, CN or P 1 -Sp 1 -, particularly preferably straight-chain or branched, optionally mono- or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms (where the alkenyl and alkynyl radicals have at least two C atoms and the branched radicals have at least three C atoms),
R 0 , R 00 each, independently of one another and identically or differently on each occurrence, denote H or alkyl having 1 to 12 C atoms,
X 1 , X 2 and X 3 each, independently of one another, denote —CO—O—, —O—CO— or a single bond,
Z 1 denotes —O—, —CO—, —C(R y R z )— or —CF 2 CF 2 —,
R y and R z each, independently of one another, denote H, F, CH 3 or CF 3 ,
Z 2 denotes —CO—O—, —O—CO—, —CH 2 O—, —OCH 2 —, —CF 2 O—, —OCF 2 — or —(CH 2 ) n —, where n is 2, 3 or 4,
L on each occurrence, identically or differently, denotes F, Cl, CN or straight-chain or branched, optionally mono- or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms,
L′ and L″ each, independently of one another, denote H, F or Cl,
r denotes 0, 1, 2, 3 or 4,
s denotes 0, 1, 2 or 3,
t denotes 0, 1 or 2,
x denotes 0 or 1.
15. The liquid-crystalline medium according to claim 1 , additionally comprising at least one reactive mesogen of the formulae RM-1 to RM-98,
16. A process for the preparation of a liquid-crystalline medium according to claim 1 , comprising mixing at least one compound of the formula I and at least one compound of the formulae I-A to I-K with at least one further liquid-crystalline compound, and additives are optionally added.
17. An electro-optical display having active-matrix or passive matrix addressing, said display comprising as a dielectric, a liquid-crystalline medium according to claim 1 .
18. The electro-optical display according to claim 17 that is a VA, PM-VA, PSA, PS-VA, PALC, FFS, PS-FFS, IPS or PS-IPS display.
19. The electro-optical display according to claim 17 , operated in self-aligning VA mode.
20. The liquid-crystalline medium according to claim 14 , wherein P 1 , P 2 or P 3 is a polymerizable group having an acrylate, methacrylate, fluoroacrylate, oxetane, vinyl, vinyloxy or epoxide group, and
Sp 1 , Sp 2 or Sp 3 are —(CH 2 ) p1 —, —(CH 2 ) p1 —O—, —(CH 2 ) p1 —CO—O— or —(CH 2 ) p1 —O—CO—O—, in which p1 is an integer from 1 to 12, and where the linking to the adjacent ring in the last-mentioned groups takes place via the O atom.
21. The liquid crystalline mixture according to claim 1 , further comprising
22. The liquid crystalline medium according to claim 21 , comprising