Liquid-crystalline medium

Abstract

The invention relates to a liquid-crystalline medium which comprises at least one compound of the formula I, ##STR00001##
wherein the radicals R.sup.11, L.sup.1, L.sup.2, n and A are as defined herein, and to the use thereof for an active-matrix display, in particular based on the VA, PSA, PS-VA, PA-VA, PALC, FFS, PS-FFS, IPS or PS-IPS effect.

Claims

1. A liquid-crystalline medium comprising: (a) one or more compounds of formula I1, ##STR00363## in which alkenyl denotes CH.sub.2=CH—CH.sub.2—CH.sub.2—, and L.sup.1 and L.sup.2 each, independently of one another, denote F or Cl, wherein the amount of compounds of formula I1 in the medium is ≥5%; (b) one or more compounds selected from the compounds of formulae I 3 and one or more compounds selected from the compounds of formulae I4, ##STR00364## in which alkenyl denotes CH.sub.2=CH—, and L.sup.1 and L.sup.2 each, independently of one another, denote F or Cl, wherein the amount of compounds of formula I13 in the medium is ≥5% and the amount of compounds of formula I4 in the medium is ≥6%; (c) optionally one or more compounds selected from the compounds of formula I2, ##STR00365## in which alkenyl denotes CH.sub.2=CH—, and L.sup.1 and L.sup.2 each, independently of one another, denote F or Cl; the compound of formula CC-n-V ##STR00366## wherein n is 3, in an amount of ≥30% by weight of based on the mixture as a whole, and (d) one or more compounds selected from formulae L-1 to L-11, EY, and T-1 to T-21: ##STR00367## ##STR00368## in which R, R.sup.1 and R.sup.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.sub.3 or at least monosubstituted by halogen, where, in addition, one or more CH.sub.2 groups in these radicals may each be replaced by —O—, —S—, ##STR00369## —C≡—, —CF.sub.2 O—, —OCF.sub.2—, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another, (O) denotes —O— or a single bond, alkyl denotes an alkyl radical having 1-6 C atoms, and s denotes 1 or 2; ##STR00370## in which R.sup.1 denotes H, an alkyl or alkenyl radical having up to 15 C atoms which is un-substituted, monosubstituted by CN or CF.sub.3 or at least monosubstituted by halogen, where, in addition, one or more CH.sub.2 groups in these radicals may each be replaced by —O—, —S—, ##STR00371## —C≡C—, —CF.sub.2O—, —OCF.sub.2—, —OC—O—or —O—CO —in such a way that O atoms are not linked directly to one another, L.sup.1 and L.sup.2 are each independently F or Cl, and R.sup.1* denotes H, an alkyl or alkenyl radical having up to 15 C atoms which is un-substituted, monosubstituted by CN or CF.sub.3 or at least monosubstituted by halogen, where, in addition, one or more CH.sub.2 groups in these radicals may each be replaced by —O—, —S—, ##STR00372## —C≡C—, —CF.sub.2O—, —OCF.sub.2—, —OC—O—or —O—CO—in such a way that O atoms are not linked directly to one another; ##STR00373## ##STR00374## ##STR00375## in which R denotes a straight-chain alkyl or alkoxy radical having 1-7 C atoms, (O) denotes —O— or a single bond, m denotes 1-6, and n denotes 0, 1, 2, 3 or 4.

2. A liquid-crystalline medium according to claim 1, wherein said medium contains one or more compounds of formula I2 ##STR00376##

3. A liquid-crystalline medium according to claim 1, further comprising one or more compounds of formula A, ##STR00377## in which X and Y each, independently of one another, denote a trans-1,4-cyclohexylene radical or a 1,4-phenylene radical, which in each case is unsubstituted or substituted by one or two identical or different radicals L.sup.1, one of the radicals R.sup.c and R.sup.d denotes an alkenyl radical having 2 to 12 C atoms, and the other of the radicals R.sup.c and R.sup.d denotes an alkyl radical having 1 to 12 C atoms, in which, in addition, one or two non-adjacent CH.sub.2 groups may each be replaced by —O—, —CH═CH—, —CO—, —OCO— or —COO— in such a way that O atoms are not linked directly to one another, L.sup.1 denotes F, Cl, CF.sub.3, OCF.sub.3 or CHF.sub.2, a denotes 1 or 2, wherein said one or more compounds of formula A are not compounds of formulae A3a and A6a.

4. A liquid-crystalline medium according to one or more of claim 1, further comprising one or more compounds selected from formulae A3a and A6a: ##STR00378## in which m denotes 1, 2, 3, 4, 5 or 6, i denotes 0, 1, 2 or 3, and R.sup.b1 denotes H, CH.sub.3 or C.sub.2H.sub.5.

5. A liquid-crystalline medium according to claim 1, further comprising one or more compounds selected from the compounds of formulae IIA, IIB and IIC, ##STR00379## in which R.sup.2A, R.sup.2B and R.sup.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.sub.3 or at least monosubstituted by halogen, where, in addition, one or more CH.sub.2 groups in these radicals may each be replaced by —O—, —S—, ##STR00380## —C≡C—, —CF.sub.2O—, —OCF.sub.2—, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another, L.sup.1-4 each, independently of one another, denote F or Cl, Z.sup.2 and Z.sup.2′ each, independently of one another, denote a single bond, —CH.sub.2CH.sub.2—, —CH═CH—, —CF.sub.2O—, —OCF.sub.2—, —CH.sub.2O—, —OCH.sub.2—, —COO—, —OCO—, —C.sub.2F.sub.4—, —CF═CF—, or —CH═CHCH.sub.2O—, p denotes 1 or 2, q denotes 0 or 1, and v denotes 1 to 6, with the proviso that the compounds of formulae IIA and IIB are not identical to the compounds of formula I1, I2, I3, or I4.

6. A liquid-crystalline medium according to one or more of claim 1, further comprising one or more compounds of formula III, ##STR00381## in which R.sup.31 and R.sup.32 each, independently of one another, denote a straight-chain alkyl, alkoxyalkyl or alkoxy radical having up to 12 C atoms, and ##STR00382## denotes ##STR00383## Z.sup.3 denotes a single bond, —CH.sub.2CH.sub.2—, —CH═CH—, —CF.sub.2O—, —OCF.sub.2—, —CH.sub.2O—, —OCH.sub.2—, —COO—, —OCO—, —C.sub.2F.sub.4—, —C.sub.4H.sub.9—, or —CF═CF—.

7. A liquid-crystalline medium according claim 1, wherein said one or more compounds selected from formulate L-1 to L-11, EY, and T-1 to T-21 are selected from one or more compounds of the formulate L-1 to L-11, ##STR00384## ##STR00385## in which R, R.sup.1 and R.sup.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.sub.3 or at least monosubstituted by halogen, where, in addition, one or more CH.sub.2 groups in these radicals may each be replaced by —O—, —S—, ##STR00386## —C≡C—, —CF.sub.2O—, —OCF.sub.2—, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another, (O) denotes —O— or a single bond, alkyl denotes an alkyl radical having 1-6 C atoms, and s denotes 1 or 2.

8. A liquid-crystalline medium according to claim 1, wherein said one or more compounds selected from formulae L-1 to L-11, EY, and T-1 to T-21 are selected from one or more compounds of the formulate T-1 to T-21, ##STR00387## ##STR00388## ##STR00389## in which R denotes a straight-chain alkyl or alkoxy radical having 1-7 C atoms, (O) denotes —O— or a single bond, m denotes 1-6, and n denotes 0, 1, 2, 3 or 4.

9. A liquid-crystalline medium according claim 1, further comprising one or more compounds of formulae O-1 to O-17, ##STR00390## ##STR00391## in which R.sup.1 and R.sup.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.sub.3 or at least monosubstituted by halogen, where, in addition, one or more CH.sub.2 groups in these radicals may each be replaced by —O—, —S—, ##STR00392## —C≡C—, —CF.sub.2O—, —OCF.sub.2—, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another.

10. A liquid-crystalline medium according claim 1, further comprising one or more indane compounds of formula In, ##STR00393## in which R.sup.11, R.sup.12, R.sup.13 each, independently of one another, denote a straight-chain alkyl, alkoxy, alkoxyalkyl or alkenyl radical having 1-5 C atoms, R.sup.12 and R.sup.13 additionally can also denote halogen, ##STR00394## denotes ##STR00395## and i denotes 0, 1 or 2.

11. A liquid-crystalline medium according to claim 1, further comprising one or more polymerizable compounds.

12. A liquid-crystalline medium according claim 11, wherein the concentration of the polymerizable compound(s), based on the total weight of the medium, is 0.01-5% by weight.

13. A liquid-crystalline medium according to claim 11, wherein the polymerizable compound(s) is (are) selected from compounds of formula M
R.sup.a-A.sup.1-(Z.sup.1-A.sup.2).sub.m-R.sup.b  M in which the individual radicals have the following meanings: R.sup.a and R.sup.b each, independently of one another, denote P, P-Sp-, H, halogen, SF.sub.5, NO.sub.2, a carbon group or a hydrocarbon group, where at least one of the radicals R.sup.a and R.sup.b denotes or contains a group P or P-Sp-, P on each occurrence, identically or differently, denotes a polymerizable group, Sp on each occurrence, identically or differently, denotes a spacer group or a single bond, A.sup.1 and A.sup.2 each, independently of one another, denote an aromatic, heteroaromatic, alicyclic or heterocyclic group, preferably having 4 to 25 ring atoms, which may also contain fused rings, and which may also be mono- or polysubstituted by L, L denotes P-Sp-, H, OH, CH.sub.2OH, halogen, SF.sub.5, NO.sub.2, a carbon group or a hydrocarbon group, Z.sup.1 on each occurrence, identically or differently, denotes —O—, —S—, —CO—, —CO—O—, —OCO—, —O—CO—O—, —OCH.sub.2—, —CH.sub.2O—, —SCH.sub.2—, —CH.sub.2S—, —CF.sub.2O—, —OCF.sub.2—, —CF.sub.2S—, —SCF.sub.2—, —(CH.sub.2).sub.a1-—, —CF.sub.2CH.sub.2—, —CH.sub.2CF.sub.2—, —(CF.sub.2).sub.n1—, —CH═CH—, —CF═CF—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH—, CR.sup.0R.sup.00 or a single bond, R.sup.0 and R.sup.00 each, independently of one another, denote H or alkyl having 1 to 12 C atoms, m denotes 0, 1, 2, 3 or 4, and n1 denotes 1, 2, 3 or 4.

14. A liquid-crystalline medium according to claim 1, further comprising one or more additives.

15. A liquid-crystalline medium according to claim 14, wherein said additive is selected from free-radical scavengers, antioxidants and/or stabilizers.

16. A liquid-crystalline medium according to claim 1, further comprising one or more stabilizers selected from the following: ##STR00396## ##STR00397## ##STR00398## ##STR00399##

17. A liquid-crystalline medium according to claim 15, wherein said medium comprises one or more stabilizers in amounts of 0.001-10% by weight, based on the total weight of the medium.

18. A process for the preparation of a liquid-crystalline medium according to claim 1, comprising mixing at least one compound of formula I1 with one or more compounds of formula I3, one or more compounds of formula I4, one or more compounds selected from formulae L-1 to L-11, EY, and T-1 to T-21, optionally one or more compounds of formula I2, and optionally adding one or more additives.

19. A process according to claim 18, further comprising mixing at least one polymerizable compound, and one or more additives are optionally added.

20. A method of generating an electro-optical effect comprising applying a voltage to a liquid-crystalline medium according to claim 1.

21. The method according to claim 20 wherein said medium is contained in a VA, PSA, PS-VA, PA-VA, IPS, PS-IPS, FFS, PS-FFS or PALC display.

22. An electro-optical display having active-matrix addressing comprising, as dielectric, a liquid-crystalline medium according to claim 1.

23. An electro-optical display according to claim 22, wherein said display is a VA, PSA, PS-VA, PA-VA, IPS, PS-IPS, FFS, UB-FFS, PS-FFS or PALC display.

24. A liquid-crystalline medium according to claim 1, further comprising one or more compounds selected from formulae BC, CR, PH-1, PH-2, BF-1, BF-2, BS-1 and BS-2: ##STR00400## in which R.sup.B1, R .sup.B2, R.sup.CR1, R.sup.CR2, R.sup.1, and R.sup.2 each, independently of one another, denote H, an alkyl or alkenyl radical having up to 15 C atoms which is un-substituted, monosubstituted by CN or CF.sub.3 or at least monosubstituted by halogen, where, in addition, one or more CH.sub.2 groups in these radicals may each be replaced by —O—, —S—, ##STR00401## —C≡C—, —CF.sub.2O—, —OCF.sub.2—, —OC—O—or —O—CO—in such a way that O atoms are not linked directly to one another, c denotes 0, 1 or 2, and d denotes 1 or 2.

25. A liquid-crystalline medium according to claim 24, wherein said one or more compounds selected from formulae BC, CR, PH-1, PH-2, BF-1, BF-2, BS-1 and BS-2 are selected from the following subformulae: ##STR00402## ##STR00403## in which alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms, alkoxy and alkoxy* each, independently of one another, denote a straight-chain alkoxy radical having 1-6 C atoms, and alkenyl and alkenyl* each, independently of one another, denote a straight-chain alkenyl radical having 2-6 C atoms.

26. A liquid-crystalline medium according to claim 7, wherein said one or more compounds selected from formulae L-1 to L-11 are selected from formulae L-1 to L-4.

27. A liquid-crystalline medium according to claim 1, wherein said one or more compounds selected from formulae L-1 to L-11, EY, T-1 to T-21 and are selected from formula EY: ##STR00404## in which R.sup.1 denotes H, an alkyl or alkenyl radical having up to 15 C atoms which is un-substituted, monosubstituted by CN or CF.sub.3 or at least monosubstituted by halogen, where, in addition, one or more CH.sub.2 groups in these radicals may each be replaced by —O—, —S—, ##STR00405## —C≡C—, —CF.sub.2O—, —OCF.sub.2—, —OC—O—or —O—CO—in such a way that O atoms are not linked directly to one another, L.sup.1 and L.sup.2 are each independently F or Cl, and R.sup.1* denotes H, an alkyl or alkenyl radical having up to 15 C atoms which is un-substituted, monosubstituted by CN or CF.sub.3 or at least monosubstituted by halogen, where, in addition, one or more CH.sub.2 groups in these radicals may each be replaced by —O—, —S—, ##STR00406## —C≡C—, —CF.sub.2O—, —OCF.sub.2—, —OC—O—or —O—CO—in such a way that O atoms are not linked directly to one another.

28. A liquid-crystalline medium according to claim 27, wherein said one or more compounds selected from formula EY are selected from the following compounds: ##STR00407## ##STR00408## ##STR00409##

29. A liquid-crystalline medium according to claim 1, further comprising one or more compounds selected from formulae Q-1 to Q-9: ##STR00410## in which R.sup.Q and X.sup.Q 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.sub.3 or at least monosubstituted by halogen, where, in addition, one or more CH.sub.2 groups in these radicals may each be replaced by —O—, —S—, ##STR00411## —C≡C—, —CF.sub.2O—, —OCF.sub.2—, —OC—O—or —O—CO—in such a way that O atoms are not linked directly to one another.

30. A liquid-crystalline medium according to claim 11, wherein said one or more polymerizable compounds are selected from the following compounds: ##STR00412## ##STR00413## ##STR00414## ##STR00415## ##STR00416## ##STR00417## ##STR00418## ##STR00419## ##STR00420##

31. A liquid-crystalline medium according to claim 1, wherein said medium further contains one or more compounds of formula A1a ##STR00421## wherein m denotes 1, 2, 3, 4, 5 or 6, and R.sup.b1 denotes H, CH.sub.3 or C.sub.2H.sub.5, and wherein said compound of formula A1a is not a compound of formula CC-n-V wherein n is 3.

32. A liquid-crystalline medium according to claim 31, wherein said one or more compounds of formula Ala are selected from the following compounds ##STR00422##

33. A liquid-crystalline medium according to claim 1, wherein the amount of the compound of formula CC-n-V, wherein n is 3, is 30% to 50% by weight of based on the mixture as a whole.

34. A liquid-crystalline medium according to claim 24, wherein said one or more compounds selected from formulae BC, CR, PH-1, PH-2, BF-1, BF-2, BS-1 and BS-2 are selected from one or more compounds of the formulae BF-1, BF-2, BS-1 and BS-2.

Description

WORKING EXAMPLES

(1) The following examples are intended to explain the invention without restricting it. In the examples, m.p. denotes the melting point and C denotes the clearing point of a liquid-crystalline substance in degrees Celsius; boiling points are denoted by b.p. Furthermore:

(2) C denotes crystalline solid state, S denotes smectic phase (the index denotes the phase type), N denotes nematic state, Ch denotes cholesteric phase, I denotes isotropic phase, T.sub.g denotes glass transition temperature. The number between two symbols indicates the conversion temperature in degrees Celsius.

(3) The host mixture used for determination of the optical anisotropy Δn of the compounds of the formula I is the commercial mixture ZLI-4792 (Merck KGaA). The dielectric anisotropy Δ∈ is determined using commercial mixture ZLI-2857. The physical data of the compound to be investigated are obtained from the change in the dielectric constants of the host mixture after addition of the compound to be investigated and extrapolation to 100% of the compound employed. In general, 10% of the compound to be investigated are dissolved in the host mixture, depending on the solubility.

(4) Unless indicated otherwise, parts or percent data denote parts by weight or percent by weight.

(5) Above and below, V.sub.0 denotes the threshold voltage, capacitive [V] at 20° C. Δn denotes the optical anisotropy measured at 20° C. and 589 nm Δ∈ denotes the dielectric anisotropy at 20° C. and 1 kHz cl.p. denotes the clearing point [° C.] K.sub.1 denotes the elastic constant, “splay” deformation at 20° C. [pN] K.sub.3 denotes the elastic constant, “bend” deformation at 20° C. [pN] γ.sub.1 denotes the rotational viscosity measured at 20° C. [mPa.Math.s], determined by the rotation method in a magnetic field LTS denotes the low-temperature stability (nematic phase), determined in test cells.

(6) The display used for measurement of the threshold voltage has two plane-parallel outer plates at a separation of 20 μm and electrode layers with overlying alignment layers of SE-1211 (Nissan Chemicals) on the insides of the outer plates, which effect a homeotropic alignment of the liquid crystals.

(7) All concentrations in this application relate to the corresponding mixture or mixture component, unless explicitly indicated otherwise. All physical properties are determined as described in “Merck Liquid Crystals, Physical Properties of Liquid Crystals”, status November 1997, Merck KGaA, Germany, and apply for a temperature of 20° C., unless explicitly indicated otherwise.

Mixture Examples

Comparative Example V1

(8) TABLE-US-00008 CC-3-V 34.50% Clearing point [° C.]: 75.5 CC-3-V1 8.00% Δn [589 nm, 20° C.]: 0.1077 CCY-3-O1 6.00% Δε [1 kHz, 20° C.]: −3.0 CCY-3-O2 10.00% ε.sub.∥ [1 kHz, 20° C.]: 3.5 CCY-4-O2 5.00% K.sub.1 [pN, 20° C.]: 13.9 CPY-3-O2 11.50% K.sub.3 [pN, 20° C.]: 15.7 PY-3-O2 20.00% γ.sub.1 [mPa .Math. s, 20° C.]: 88 PYP-2-3 5.00% V.sub.0 [20° C., V]: 2.41 γ.sub.1/K.sub.3: 5.61

Example M1

(9) TABLE-US-00009 CC-3-V 34.50% Clearing point [° C.]: 74.5 CC-3-V1 8.00% Δn [589 nm, 20° C.]: 0.1084 CCY-3-O1 4.00% Δε [1 kHz, 20° C.]: −3.0 CCY-3-O2 11.00% ε.sub.∥ [1 kHz, 20° C.]: 3.5 CCY-4-O2 5.00% K.sub.1 [pN, 20° C.]: 13.6 CPY-3-O2 11.00% K.sub.3 [pN, 20° C.]: 15.5 PY-3-O2 11.50% γ.sub.1 [mPa .Math. s, 20° C.]: 83 PYP-2-3 5.00% V.sub.0 [20° C., V]: 2.40 PY-V2-O2 10.00% γ.sub.1/K.sub.3: 5.35

(10) Mixture M1 according to the invention comprising the compound PY-V2-02 of the formula I has a significantly lower value for the ratio γ.sub.1/K.sub.3 than the comparative mixture V1.

Example M2

(11) TABLE-US-00010 CC-3-V 34.50% Clearing point [° C.]: 75.0 CC-3-V1 8.00% Δn [589 nm, 20° C.]: 0.1080 CCY-3-O1 5.50% Δε [1 kHz, 20° C.]: −3.1 CCY-3-O2 10.00% ε.sub.∥ [1 kHz, 20° C.]: 3.5 CCY-V-O2 6.00% K.sub.1 [pN, 20° C.]: 13.9 CPY-3-O2 11.50% K.sub.3 [pN, 20° C.]: 15.9 PY-3-O2 19.60% γ.sub.1 [mPa .Math. s, 20° C.]: 86 PYP-2-3 5.00% V.sub.0 [20° C., V]: 2.40 γ.sub.1/K.sub.3: 5.41

(12) Mixture M2 according to the invention comprising the compound CCY-V-O2 of the formula I has a significantly lower value for the ratio γ.sub.1/K.sub.3 than the comparative mixture V1.

Example M3

(13) TABLE-US-00011 CC-3-V 34.50% Clearing point [° C.]: 74.5 CC-3-V1 8.00% Δn [589 nm, 20° C.]: 0.1075 CCY-3-O1 5.00% Δε [1 kHz, 20° C.]: −2.9 CCY-3-O2 11.00% ε.sub.∥ [1 kHz, 20° C.]: 3.5 CCY-4-O2 6.00% K.sub.1 [pN, 20° C.]: 13.5 CPY-V-O2 5.00% K.sub.3 [pN, 20° C.]: 15.1 CPY-V-O4 5.00% γ.sub.1 [mPa .Math. s, 20° C.]: 81 PY-3-O2 9.00% V.sub.0 [20° C., V]: 2.42 PYP-2-3 10.00% γ.sub.1/K.sub.3: 5.36 PY-V2-O2 5.00% PP-1-2V1 1.50%

(14) Mixture M3 according to the invention comprising the compounds PY-V2-O2, CPY-V-O2 and CPY-V-O4 of the formula I has a significantly lower value for the ratio γ.sub.1/K.sub.3 than the comparative mixture V1.

Example M4

(15) TABLE-US-00012 CC-3-V 35.00% Clearing point [° C.]: 75.0 CC-3-V1 8.00% Δn [589 nm, 20° C.]: 0.1078 CCY-3-O1 4.00% Δε [1 kHz, 20° C.]: −3.0 CCY-3-O2 11.00% ε.sub.∥ [1 kHz, 20° C.]: 3.5 CCY-V-O2 6.00% K.sub.1 [pN, 20° C.]: 13.7 CPY-3-O2 11.00% K.sub.3 [pN, 20° C.]: 15.9 PY-3-O2 10.50% γ.sub.1 [mPa .Math. s, 20° C.]: 82 PY-V2-O2 10.00% V.sub.0 [20° C., V]: 2.42 PYP-2-3 4.00% γ.sub.1/K.sub.3: 5.16

(16) Mixture M4 according to the invention comprising the compounds PY-V2-O2 and CCY-V-O2 of the formula I has a significantly lower value for the ratio γ.sub.1/K.sub.3 than the comparative mixture V1.

Example M5

(17) TABLE-US-00013 CC-3-V 34.50% Clearing point [° C.]: 74.5 CC-3-V1 8.00% Δn [589 nm, 20° C.]: 0.1076 CCY-3-O1 6.00% Δε [1 kHz, 20° C.]: −2.9 CCY-3-O2 11.50% ε.sub.∥ [1 kHz, 20° C.]: 3.5 CCY-4-O2 6.00% K.sub.1 [pN, 20° C.]: 13.4 CPY-V-O2 4.50% K.sub.3 [pN, 20° C.]: 15.3 CPY-V-O4 4.50% γ.sub.1 [mPa .Math. s, 20° C.]: 80 PY-3-O2 8.50% V.sub.0 [20° C., V]: 2.42 PYP-2-3 10.00% γ.sub.1/K.sub.3: 5.23 PY-V2-O2 5.00% PP-1-2V1 1.50%

(18) Mixture M5 according to the invention comprising the compounds PY-V2-O2, CPY-V-O2 and CPY-V-O4 of the formula I has a significantly lower value for the ratio γ.sub.1/K.sub.3 than the comparative mixture V1.

Example M6

(19) TABLE-US-00014 CC-3-V 38.50% Clearing point [° C.]: 74.5 CC-3-V1 7.00% Δn [589 nm, 20° C.]: 0.1079 CCY-3-O2 10.50% Δε [1 kHz, 20° C.]: −2.9 CPY-3-O2 4.00% ε.sub.∥ [1 kHz, 20° C.]: 3.5 PY-3-O2 11.50% K.sub.1 [pN, 20° C.]: 13.4 PGIY-2-O4 5.00% K.sub.3 [pN, 20° C.]: 15.2 PP-1-2V1 1.50% γ.sub.1 [mPa .Math. s, 20° C.]: 77 PY-V2-O2 5.00% V.sub.0 [20° C., V]: 2.43 CPY-V-O2 6.00% γ.sub.1/K.sub.3: 5.07 CPY-V-O4 5.00% CCY-V-O2 6.00%

(20) Mixture M6 according to the invention comprising the compounds PY-V2-O2, CPY-V-O2, CPY-V-O4 and CCY-V-O2 of the formula I has a significantly lower value for the ratio γ.sub.1/K.sub.3 than the comparative mixture V1.

Example M7

(21) TABLE-US-00015 CC-3-V 42.00% Clearing point [° C.]: 75.0 CCY-3-O1 9.00% Δn [589 nm, 20° C.]: 0.0994 CCY-3-O2 10.00% Δε [1 kHz, 20° C.]: −3.3 CCY-V-O2 9.00% ε.sub.∥ [1 kHz, 20° C.]: 3.6 CPY-V-O2 6.50% K.sub.1 [pN, 20° C.]: 12.8 CPY-V-O4 4.00% K.sub.3 [pN, 20° C.]: 15.1 CY-3-O2 0.50% γ.sub.1 [mPa .Math. s, 20° C.]: 79 PY-3-O2 9.00% V.sub.0 [20° C., V]: 2.26 PY-V2-O2 10.00% γ.sub.1/K.sub.3: 5.23

(22) Mixture M7 according to the invention comprising the compounds PY-V2-O2, CPY-V-O2, CPY-V-O4 and CCY-V-O2 of the formula I has a significantly lower value for the ratio γ.sub.1/K.sub.3 than the comparative mixture V1.

Example P1

(23) For the preparation of a PS-VA mixture, 99.7% of the mixture according to Example M1 is mixed with 0.3% of the polymerizable compound of the formula

(24) ##STR00355##

(25) The PS-VA mixture is introduced into a cell having homeotropic alignment. After application of a voltage of 24 V, the cell is irradiated with UV light having a power of 100 mW/cm.sup.2.

Example M8

(26) TABLE-US-00016 CC-3-V 36.00% Clearing point [° C.]: 75.0 CC-3-V1 8.50% Δn [589 nm, 20° C.]: 0.1094 CLY-3-O2 6.00% Δε [1 kHz, 20° C.]: −3.0 CPY-3-O2 4.00% ε.sub.∥ [1 kHz, 20° C.]: 3.5 CPY-2-O2 8.00% ε.sub.⊥ [1 kHz, 20° C.]: 6.5 PY-4-O2 5.00% K.sub.1 [pN, 20° C.]: 13.0 PYP-2-3 3.00% K.sub.3 [pN, 20° C.]: 14.5 PGIY-2-O4 5.00% γ.sub.1 [mPa .Math. s, 20° C.]: 82 CPY-V-O2 8.00% V.sub.0 [20° C., V]: 2.34 CPY-V-O4 6.00% γ.sub.1/K.sub.3: 5.65 CY-3-O2 10.50%

Example M9

(27) TABLE-US-00017 CC-3-V 35.50% Clearing point [° C.]: 74.0 CC-3-V1 9.00% Δn [589 nm, 20° C.]: 0.1070 CCY-3-O1 7.00% Δε [1 kHz, 20° C.]: −3.1 CLY-3-O2 5.00% ε.sub.∥ [1 kHz, 20° C.]: 3.5 PY-3-O2 8.00% ε.sub.⊥ [1 kHz, 20° C.]: 6.7 PYP-2-3 3.00% K.sub.1 [pN, 20° C.]: 13.1 PGIY-2-O4 5.00% K.sub.3 [pN, 20° C.]: 14.9 CPY-V-O4 5.00% γ.sub.1 [mPa .Math. s, 20° C.]: 80 CPY-V-O2 5.00% V.sub.0 [20° C., V]: 2.31 CCY-V-O2 8.00% γ.sub.1/K.sub.3: 5.34 PY-V2-O2 6.00% LTS bulk [−25° C.]: >1000 h CY-3-O2 4.50%

Example P2

(28) For the preparation of a PS-VA mixture, 99.7% of the mixture according to Example M9 is mixed with 0.3% of the polymerizable compound of the formula

(29) ##STR00356##

(30) The PS-VA mixture is introduced into a cell having homeotropic alignment. After application of a voltage of 24 V, the cell is irradiated with UV light having a power of 100 mW/cm.sup.2.

Example M10

(31) TABLE-US-00018 CY-3-O2 14.00% Clearing point [° C.]: 86.5 CY-3-O4 6.00% Δn [589 nm, 20° C.]: 0.1024 CCY-3-O1 8.50% Δε [1 kHz, 20° C.]: −5.0 CCY-3-O2 11.00% ε.sub.∥ [1 kHz, 20° C.]: 3.9 CCY-4-O2 8.50% ε.sub.⊥ [1 kHz, 20° C.]: 8.9 CPY-3-O2 4.50% K.sub.1 [pN, 20° C.]: 13.8 CC-3-V 25.00% K.sub.3 [pN, 20° C.]: 16.9 PY-V2-O2 5.50% γ.sub.1 [mPa .Math. s, 20° C.]: 146 CPY-V-O2 6.00% V.sub.0 [20° C., V]: 1.95 CPY-V-O4 5.00% γ.sub.1/K.sub.3: 8.64 CCY-V-O2 6.00% LTS bulk [−25° C.]: >1000 h

Example M11

(32) TABLE-US-00019 CC-3-V 33.00% Clearing point [° C.]: 74.5 CC-3-V1 8.00% Δn [589 nm, 20° C.]: 0.1097 CCY-3-O2 11.50% Δε [1 kHz, 20° C.]: −3.5 CCY-V-O2 6.00% ε.sub.∥ [1 kHz, 20° C.]: 3.6 CPY-3-O2 11.00% ε.sub.⊥ [1 kHz, 20° C.]: 7.1 CLY-3-O2 5.00% K.sub.1 [pN, 20° C.]: 14.2 PY-1-O4 6.00% K.sub.3 [pN, 20° C.]: 16.5 PY-3-O2 11.00% γ.sub.1 [mPa .Math. s, 20° C.]: 91 PY-1-O2 5.00% V.sub.0 [20° C., V]: 2.29 PGIY-2-O4 3.00% γ.sub.1/K.sub.3: 5.52 PP-1-2V1 0.50%

Example P3

(33) For the preparation of a PS-VA mixture, 99.7% of the mixture according to Example M11 is mixed with 0.25% of the polymerizable compound of the formula

(34) ##STR00357##

(35) The PS-VA mixture is introduced into a cell having homeotropic alignment. After application of a voltage of 24 V, the cell is irradiated with UV light having a power of 100 mW/cm.sup.2.

Example M12

(36) TABLE-US-00020 CC-3-V 34.50% Clearing point [° C.]: 74 CC-3-V1 8.00% Δn [589 nm, 20° C.]: 0.1079 CCY-3-O2 11.50% Δε [1 kHz, 20° C.]: −3.3 CCY-V-O2 6.00% ε.sub.∥ [1 kHz, 20° C.]: 3.6 CPY-V-O2 6.00% ε.sub.⊥ [1 kHz, 20° C.]: 6.9 CPY-V-O4 5.50% K.sub.1 [pN, 20° C.]: 13.7 CLY-3-O2 5.00% K.sub.3 [pN, 20° C.]: 15.7 PY-1-O4 3.50% γ.sub.1 [mPa .Math. s, 20° C.]: 84 PY-3-O2 11.00% V.sub.0 [20° C., V]: 2.30 PY-1-O2 5.00% γ.sub.1/K.sub.3: 5.35 PGIY-2-O4 3.00% PP-1-2V1 1.00%

Example M13

(37) LC mixture M12 is additionally stabilized with

(38) ##STR00358##

Example M14

(39) TABLE-US-00021 CC-3-V 32.00% Clearing point [° C.]: 84.50 CPY-2-O2 11.00% Δn [589 nm, 20° C.]: 0.1084 CPY-3-O2 11.00% Δε [1 kHz, 20° C.]: −4.5 CCY-V-O2 10.00% ε.sub.∥ [1 kHz, 20° C.]: 3.8 CCY-V-O4 11.00% ε.sub.⊥ [1 kHz, 20° C.]: 8.3 CAIY-3-O2 8.50% K.sub.1 [pN, 20° C.]: 14.1 CEY-3-O2 4.00% K.sub.3 [pN, 20° C.]: 16.4 PY-3-O2 12.50% γ.sub.1 [mPa .Math. s, 20° C.]: 131 V.sub.0 [20° C., V]: 2.01 γ.sub.1/K.sub.3: 7.99

Example M15

(40) LC mixture M14 is additionally stabilized with

(41) ##STR00359##

Example M16

(42) TABLE-US-00022 CC-3-V 32.00% Clearing point [° C.]: 86 CPY-2-O2 11.00% Δn [589 nm, 20° C.]: 0.1113 CPY-3-O2 11.00% Δε [1 kHz, 20° C.]: −4.6 CCY-V-O2 10.00% ε.sub.∥ [1 kHz, 20° C.]: 3.9 CCY-V-O4 10.00% ε.sub.⊥ [1 kHz, 20° C.]: 8.4 CAIY-3-O2 11.00% K.sub.1 [pN, 20° C.]: 14.1 PY-3-O2 15.00% K.sub.3 [pN, 20° C.]: 16.4 γ.sub.1 [mPa .Math. s, 20° C.]: 137 V.sub.0 [20° C., V]: 2.00 γ.sub.1/K.sub.3: 8.35

Example M17

(43) LC mixture M16 is additionally stabilized with

(44) ##STR00360##

Example M18

(45) LC mixture M11 is additionally stabilized with

(46) ##STR00361##

Example M19

(47) LC mixture M12 is additionally stabilized with

(48) ##STR00362##

(49) Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The preceding preferred specific embodiments and examples are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever.

(50) 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.

(51) The entire disclosures of all applications, patents and publications, cited herein and of corresponding German application No. 102014012641.2, filed Aug. 22, 2014, are incorporated by reference herein.