Liquid-crystalline medium

Abstract

A liquid-crystal material (LC media) containing thiophene compounds which are stabilized by sterically hindered amines or amine derivatives (HALS, hindered amine light stabilizers), where the LC media contains one or more compounds of formula 13 ##STR00001##
and one or more compounds of formula H ##STR00002##
and liquid-crystal displays (LC displays) which contain these LC materials.

Claims

1. An LC medium, comprising one or more compounds of the formula I-3-9 and/or I-3-10 in an amount of 1% to 40%, ##STR00210## in which n and m independently from one another, denote an integer from 1 to 12; and 100 ppm to 1,000 ppm of compound H-10 ##STR00211## and one or more of the following compounds ##STR00212## in which R.sup.3 is an alkyl radical having 1 to 15 C atoms, wherein one or more CH.sub.2 groups, including terminal C atoms, may each be replaced, independently of one another, by CC, CHCH, ##STR00213## O, S, (CO)O, or O(CO) in such a way that O or S atoms are not linked directly to one another, and in which one or more H atoms may be replaced by F or Cl, or H, ##STR00214## on each appearance, independently of one another, are ##STR00215## L.sup.31 and L.sup.32 independently of one another, denote H or F, L.sup.33 is H or CH.sub.3, X.sup.3 denotes halogen, halogenated alkyl or alkoxy having 1 to 3 C atoms or halogenated alkenyl or alkenyloxy having 2 or 3 C atoms, and n denotes 0, 1, 2 or 3; and wherein the LC medium has a positive dielectric anisotropy.

2. The LC medium according to claim 1, further comprising one or more compounds of the following formulae ##STR00216## ##STR00217## in which R.sup.1 and R.sup.2 denote, each independently, H, F, Cl, Br, CN, SCN, NCS, SF.sub.5 or a straight-chain alkyl having 1 to 12 C atoms or a branched alkyl having 3 to 12 C atoms, in which one or more non-adjacent CH.sub.2 groups may each be replaced, independently of one another, by CHCH, CC, O, CO, COO, OCO, or OCOO in such a way that O atoms are not linked directly to one another, and in which one or more H atoms may be replaced by F, Cl or Br, and L.sup.2 to L.sup.6 each independently denotes H or F.

3. The LC medium according to claim 1, additionally comprising one or more compounds of formula II and/or III, from which the compounds of formulae III-1a, III-1b, III-1e, III-1f, III-2 and III-3 are excluded: ##STR00218## in which R.sup.2 is an alkyl radical having 1 to 15 C atoms, wherein one or more CH.sub.2 groups, including terminal C atoms, may each be replaced, independently of one another, by CC, CHCH, ##STR00219## O, S, (CO)O, or O(CO) in such a way that O or S atoms are not linked directly to one another, and in which one or more H atoms may be replaced by F or Cl, or H, ##STR00220## on each appearance, independently of one another, denote ##STR00221## L.sup.21 and L.sup.22 denote H or F, L.sup.23 is H or CH.sub.3, X.sup.2 denotes halogen, halogenated alkyl or alkoxy having 1 to 3 C atoms or halogenated alkenyl or alkenyloxy having 2 or 3 C atoms, m denotes 0, 1, 2 or 3, R.sup.3 is an alkyl radical having 1 to 15 C atoms, wherein one or more CH.sub.2 groups, including terminal C atoms, may each be replaced independently of one another, by CC, CHCH, ##STR00222## O, S, (CO)O, or O(CO) in such a way that O or S atoms are not linked directly to one another, and in which one or more H atoms may be replaced by F or Cl, or H, ##STR00223## on each appearance, independently of one another, are ##STR00224## L.sup.31 and L.sup.32 independently of one another, denote H or F, L.sup.33 is H or CH.sub.3, X.sup.31 denotes halogen, halogenated alkyl or alkoxy having 1 to 3 C atoms or halogenated alkenyl or alkenyloxy having 2 or 3 C atoms, Z.sup.3 denotes CH.sub.2CH.sub.2, CF.sub.2CF.sub.2, COO, trans-CHCH, trans-CFCF, CH.sub.2O or a single bond, and n denotes 0, 1, 2 or 3.

4. The LC medium according to claim 1, additionally comprising one or more compounds of the following formulae, ##STR00225## in which R.sup.41 and R.sup.42 each, independently of one another, is an alkyl radical having 1 to 15 C atoms, wherein one or more CH.sub.2 groups, including terminal C atoms, may each be replaced, independently of one another, by CC, CHCH, ##STR00226## O, S, (CO)O, or O(CO) in such a way that O or S atoms are not linked directly to one another, and in which one or more H atoms may be replaced by F or Cl, or H, ##STR00227## independently of one another and, if ##STR00228## occurs twice, also these independently of one another, denote ##STR00229## Z.sup.41 and Z.sup.42 each, independently of one another and, if Z.sup.41 occurs twice, also these independently of one another, denotes CH.sub.2CH.sub.2, COO, trans-CHCH, trans-CFCF, CH.sub.2O, CF.sub.2O, CC or a single bond, p denotes 0, 1 or 2, and R.sup.51 and R.sup.52 each, independently of one another, is an alkyl radical having 1 to 15 C atoms, wherein one or more CH.sub.2 groups, including terminal C atoms, may each be replaced, independently of one another, by CC, CHCH, ##STR00230## O, S, (CO)O, or O(CO) in such a way that O or S atoms are not linked directly to one another, and in which one or more H atoms may be replaced by F or Cl, or H, ##STR00231## if present, each, independently of one another, denote ##STR00232## Z.sup.51 to Z.sup.53 each, independently of one another, denotes CH.sub.2CH.sub.2, CH.sub.2O, CHCH, CC, COO or a single bond, i and j each, independently of one another, denotes 0 or 1, (i+j) denotes 0, 1 or 2, wherein the rings optionally may each be substituted by one or two alkyl groups.

5. The LC medium according to claim 1, additionally comprising one or more compounds of the following formulae, ##STR00233## wherein R.sup.61 denotes an unsubstituted alkyl radical having 1 to 7 C atoms, R.sup.62 denotes an unsubstituted alkyl radical having 1 to 7 C atoms, an unsubstituted alkoxy radical having 1 to 6 C atoms, C.sub.3-5-cycloalkyloxy or an unsubstituted alkenyloxy radical having 2 to 6 C atoms, L.sup.61, L.sup.62 are independently H or methyl, 1 denotes 0 or 1, R.sup.71 denotes an unsubstituted alkyl radical having 1 to 7 C atoms, R.sup.72 denotes an unsubstituted alkyl radical having 1 to 7 C atoms, L.sup.71, L.sup.72 are independently H or methyl, ##STR00234## independently denote ##STR00235## R.sup.81 denotes an unsubstituted alkyl radical having 1 to 7 C atoms, or an unsubstituted alkoxy radical having 1 to 6 C atoms, R.sup.82 denotes an unsubstituted alkyl radical having 1 to 7 C atoms, or an unsubstituted alkoxy radical having 1 to 6 C atoms, L.sup.81, L.sup.82 are independently H or methyl, ##STR00236## denotes ##STR00237## Z.sup.8 denotes (CO)O, CH.sub.2O, CF.sub.2O or CH.sub.2CH.sub.2, denotes 0 or 1, R.sup.91 and R.sup.92 independently of one another denote an unsubstituted alkyl radical having 1 to 7 C atoms, R.sup.91 denotes an alkyl radical having 2 to 5 C atoms, R.sup.92 denotes an alkyl or alkoxy radical having 2 to 5 C atoms, or an alkenyloxy radical having 2 to 4 C atoms, ##STR00238## denotes ##STR00239## p and q independently of each other denote 0 or 1.

6. The LC medium according to claim 1, further comprising one or more compounds of formula IVa ##STR00240## in which R.sup.41 denotes an unsubstituted alkyl radical having 1 to 7 C atoms or an unsubstituted alkenyl radical having 2 to 7 C atoms, and R.sup.42 denotes an unsubstituted alkyl radical having 1 to 7 C atoms, an unsubstituted alkenyl radical having 2 to 7 C atoms, or an unsubstituted alkoxy radical having 1 to 6 C atoms.

7. The LC medium according to claim 1, wherein the total concentration of the one or more compounds of formula I-3-9 and/or I-3-10 in the medium as a whole is 1% to 25%.

8. The LC medium according to claim 1, wherein the total concentration of the compound of formula H-10 in the LC medium is 1,000 ppm.

9. An electro-optical device comprising an LC display comprising an LC medium according to claim 1.

10. An LC display containing the LC medium according to claim 1.

11. The display according to claim 10, which is based on an IPS or FFS effect.

12. A process for preparing the LC medium according to claim 1, comprising mixing one or more compounds of formula I-3-9 and/or I-3-10 with the compound of formula H-10 and with one or more compounds of formula III-1a, III-1b, III-1e, III-1f, III-2 and/or III-3.

13. The LC medium according to claim 1, wherein the total concentration of the one or more compounds of formula I-3-9 and/or I-3-10 in the medium as a whole is 5% to 25%.

14. The LC medium according to claim 1, which has a positive dielectric anisotropy of 2.0 to 20.

15. The LC medium according to claim 1, which comprises one or more compounds of formulae ##STR00241##

Description

EXAMPLES

Utilized Stabilizers

(1) ##STR00209##

Mixture Examples

(2) For measuring the VHR the corresponding mixture is filled into electrooptic test cells which consist of two AF glass substrates with an approximately 20 nm thick ITO layer and a 100 nm thick polyimide layer.

(3) The VHR is measured at 60 C. with application of a voltage of 1 V/60 Hz before and after the given time. The difference in VHR before and after stress is expressed according to:
VHR=VHR (after stress)VHR (initial)

(4) Thermal stress usually causes the decrease of VHR in LC mixtures, therefore the smaller the absolute decrease of VHR value after stress, the better performance for display applications.

(5) Host MixtureH-1

(6) The following mixture is prepared according to the following table:

(7) TABLE-US-00006 CP-5-3 20.0 cl.p. [ C.]: 74 CC-3-5 10.0 n [589 nm, 20 C.]: 0.0730 CCU-2-F 12.0 n.sub.e [589 nm, 20 C.]: 1.5484 CCU-3-F 10.0 n.sub.o [589 nm, 20 C.]: 1.4754 CCU-5-F 8.0 [1 kHz, 20 C.]: 5.4 CCEG-3-F 10.0 .sub.|| [1 kHz, 20 C.]: 8.6 CCEG-5-F 10.0 .sub. [1 kHz, 20 C.]: 3.2 CCG-3-OT 10.0 K.sub.1 [pN, 20 C.]: 12.6 CCG-5-OT 10.0 K.sub.3 [pN, 20 C.]: 15.6 100.0 K.sub.3/K.sub.1 [pN, 20 C.]: 1.23 V.sub.0 [V, 20 C.]: 1.62
and 10% w/w of PUS-3-2 according to the above-given acronym tables are added resulting in Host Mixture H-1

(8) TABLE-US-00007 Mixture Initial After 1000 h H-1 VHR/% 95.1 19.5

(9) Host MixtureH-2

(10) The following mixture is prepared according to the following table:

(11) TABLE-US-00008 CP-5-3 20.0 cl.p. [ C.]: 74 CC-3-5 10.0 n [589 nm, 20 C.]: 0.0730 CCU-2-F 12.0 n.sub.e [589 nm, 20 C.]: 1.5484 CCU-3-F 10.0 n.sub.o [589 nm, 20 C.]: 1.4754 CCU-5-F 8.0 [1 kHz, 20 C.]: 5.4 CCEG-3-F 10.0 .sub.|| [1 kHz, 20 C.]: 8.6 CCEG-5-F 10.0 .sub. [1 kHz, 20 C.]: 3.2 CCG-3-OT 10.0 K.sub.1 [pN, 20 C.]: 12.6 CCG-5-OT 10.0 K.sub.3 [pN, 20 C.]: 15.6 100.0 K.sub.3/K.sub.1 [pN, 20 C.]: 1.23 V.sub.0 [V, 20 C.]: 1.62
and 10% w/w of PUS-2-2 according to the above-given acronym tables are added resulting in Host Mixture H-2
Mixture M-1

(12) To mixture H-1, 0.03% w/w of the stabilizer S-1 is added resulting in Mixture M-1

(13) TABLE-US-00009 Mixture Initial After 1000 h M-1 VHR/% 73.5 82.4
Comparative Mixture CM-1

(14) To mixture H-1, 0.03% w/w of Tinuvin770 is added resulting in Comparative mixture CM-1 comparative to mixture M-1.

(15) TABLE-US-00010 Mixture Initial After 1000 h CM-1 VHR/% 40.1 66.0
Mixture M-2

(16) To mixture H-1, 0.1% w/w of S-1 is added resulting in Mixture M-2

(17) TABLE-US-00011 Mixture Initial After 1000 h M-2 VHR/% 82.9 74.6
Mixture M-3

(18) To mixture H-1, 0.1% w/w of S-2 is added resulting in Mixture M-4.

(19) TABLE-US-00012 Mixture Initial After 1000 h M-3 VHR/% 78.9 83.8
Comparative Mixture CM-2

(20) To mixture H-1, 0.1% w/w of Tinuvin770 is added resulting in Comparative Mixture CM-2 comparative to mixture M-2 and M-3.

(21) TABLE-US-00013 Mixture Initial After 1000 h CM-2 VHR/% 67.9 53.2
Mixture M-4

(22) To mixture H-1, 10% w/w of mixture M-2 is added resulting in Mixture M-4

(23) Mixture M-5

(24) To mixture H-1, 10% w/w of mixture M-3 is added resulting in Mixture M-5

(25) Comparative Mixture CM-3

(26) To mixture H-1, 10% w/w of mixture CM-2 is added resulting in Comparative Mixture CM-3 comparative to mixture M-4 and M-5.

(27) Mixture M-6

(28) To mixture H-2, 0.1% w/w of S-1 is added resulting in Mixture M-6.

(29) Mixture M-7

(30) The following mixture is prepared according to the following table resulting in Mixture M-7

(31) TABLE-US-00014 CC-3-V 47.0 CC-3-V1 4.5 CLP-3-T 7.0 PGP-1-2V 5.5 PGP-2-2V 10.0 PGU-2-F 1.0 PGUQU-3-F 4.0 PGUQU-4-F 2.5 PP-1-2V1 7.5 PPGU-3-F 0.99 PUS-3-2 10.0 S-1 0.01 100
Mixture M-8

(32) The following mixture is prepared according to the following table resulting in Mixture M-8

(33) TABLE-US-00015 CC-3-V 47.0 CC-3-V1 4.5 CLP-3-T 7.0 PGP-1-2V 5.5 PGP-2-2V 10.0 PGU-2-F 1.0 PGUQU-3-F 4.0 PGUQU-4-F 2.5 PP-1-2V1 7.5 PPGU-3-F 0.99 PUS-3-2 10.0 S-2 0.01 100

(34) The preceding examples can be repeated with similar success by substituting the generically or specifically described reactants and/or operating conditions of this invention for those used in the preceding examples.

(35) From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.