Liquid crystal medium and high-frequency components containing the same

Abstract

The present invention relates to liquid-crystalline media comprising at least one compound of the formula I and at least one compound of the formula II
or at least one compound of the formula I and at least one compound of the formula III
or at least one compound of the formula II and at least one compound of the formula III
or at least one compound of the formula I and at least one compound of the formula II and at least one compound of the formula III: ##STR00001##
in which the parameters have the meaning indicated in Claim 1, and to components comprising these media for high-frequency technology, in particular phase shifters and microwave array antennas.

Claims

1. A liquid-crystal medium, which comprises: at least one compound of the formula I and at least one compound of the formula II and at least one compound of the formula III: ##STR00167## in which L.sup.11 denotes R.sup.11 or X.sup.11, L.sup.12 denotes R.sup.12 or X.sup.12, R.sup.11 and R.sup.12, independently of one another, denote H, unfluorinated alkyl or unfluorinated alkoxy having 1 to 15 C atoms or unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to 15 C atoms, X.sup.11 and X.sup.12, independently of one another, denote H, F, Cl, CN, NCS, SF.sub.5, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms or fluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated or fluorinated alkoxyalkyl having 2 to 7 C atoms, and ##STR00168## independently of one another, denote ##STR00169## in which L.sup.21 denotes R.sup.21 and, in the case where Z.sup.21 and/or Z.sup.22 denote trans-CHCH or trans-CFCF, alternatively denotes X.sup.21, L.sup.22 denotes R.sup.22 and, in the case where Z.sup.21 and/or Z.sup.22 denote trans-CHCH or trans-CFCF, alternatively denotes X.sup.22, R.sup.21 and R.sup.22, independently of one another, denote H, unfluorinated alkyl or unfluorinated alkoxy having 1 to 17 C atoms or unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to 15 C atoms, X.sup.21 and X.sup.22, independently of one another, denote F or Cl, CN, NCS, SF.sub.5, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms or fluorinated alkenyl, fluorinated alkenyloxy or fluorinated alkoxyalkyl having 2 to 7 C atoms, one of Z.sup.21 and Z.sup.22 denotes trans-CHCH, trans-CFCF or CC and the other, independently thereof, denotes trans-CHCH, trans-CFCF or a single bond, and ##STR00170## independently of one another, denote ##STR00171## in which L.sup.31 denotes R.sup.31 or X.sup.31, L.sup.32 denotes R.sup.32 or X.sup.32, R.sup.31 and R.sup.32, independently of one another, denote H, unfluorinated alkyl or unfluorinated alkoxy having 1 to 17 C atoms or unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to 15 C atoms, X.sup.31 and X.sup.32, independently of one another, denote H, F, Cl, CN, NCS, SF.sub.5, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms or fluorinated alkenyl, unfluorinated or fluorinated alkenyloxy or unfluorinated or fluorinated alkoxyalkyl having 2 to 7 C atoms, Z.sup.31 to Z.sup.33, independently of one another, denote trans-CHCH, trans-CFCF, CC or a single bond, and ##STR00172## independently of one another, denote ##STR00173## and optionally one or more further compounds, provided that the liquid-crystal medium has a birefringence, n, at 20 C. and 589 nm, of 0.250 or more.

2. The liquid-crystal medium according to claim 1, wherein the concentration of the compounds of the formula I in the medium is in the range from in total 15% to 70%.

3. The liquid-crystal medium according to claim 1, wherein the concentration of the compounds of the formula II in the medium is in the range from in total 1% to 60%.

4. The liquid-crystal medium according to claim 1, which comprises one or more compounds selected from the group of the compounds of the formulae I-1 to I-3: ##STR00174## in which the parameters have the respective meanings given for formula I.

5. A component for high-frequency technology, which comprises a liquid crystal medium according to claim 1.

6. A component according to claim 5, which is suitable for operation in the microwave range.

7. A component according to claim 5, which is a phase shifter.

8. A process for the preparation of a liquid-crystal medium according to claim 1, comprising mixing one or more compounds of the formula I with one or more compounds of the formulae II and one or more compounds of the formula III and optionally with one or more further compounds and/or with one or more additives.

9. Microwave antenna array, which comprises a microwave antenna array incorporating one or more components according to claim 5.

10. A liquid-crystal medium according to claim 1, wherein, in formula II, R.sup.21 and R.sup.22, independently of one another, denote H, unfluorinated alkyl or unfluorinated alkoxy having 3 to 10 C atoms or unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 3 to 10 C atoms.

11. A liquid-crystal medium according to claim 1, wherein the liquid-crystal medium has a birefringence, n, at 20 C. and 589 nm, of 0.300 or more.

12. A liquid-crystal medium according to claim 1, wherein the liquid-crystal medium has a birefringence, n, at 20 C. and 589 nm, of 0.350 or more.

13. A liquid-crystal medium according to claim 1, wherein the liquid-crystal medium has a birefringence, n, at 20 C. and 589 nm, of from 0.250 to 0.90.

14. A liquid-crystal medium according to claim 1, wherein the liquid-crystal medium has a birefringence, n, at 20 C. and 589 nm, of from 0.250 to 0.85.

15. A liquid-crystal medium according to claim 1, wherein the liquid-crystal medium has a birefringence, n, at 20 C. and 589 nm, of from 0.250 to 0.80.

16. A liquid-crystal medium according to claim 1, wherein the liquid-crystal medium has a birefringence, n, at 20 C. and 589 nm, of from 0.300 to 0.90.

17. A liquid-crystal medium according to claim 1, wherein the liquid-crystal medium has a birefringence, n, at 20 C. and 589 nm, of from 0.300 to 0.85.

18. A liquid-crystal medium according to claim 1, wherein the liquid-crystal medium has a birefringence, n, at 20 C. and 589 nm, of from 0.300 to 0.80.

19. A liquid-crystal medium according to claim 1, wherein the liquid-crystal medium has a birefringence, n, at 20 C. and 589 nm, of from 0.350 to 0.90.

20. A liquid-crystal medium according to claim 1, wherein the liquid-crystal medium has a birefringence, n, at 20 C. and 589 nm, of from 0.350 to 0.85.

21. A liquid-crystal medium according to claim 1, wherein the liquid-crystal medium has a birefringence, n, at 20 C. and 589 nm, of from 0.350 to 0.80.

22. A component for high-frequency technology, which comprises a liquid crystal medium according to claim 2.

23. A component for high-frequency technology, which comprises a liquid crystal medium according to claim 3.

24. A component for high-frequency technology, which comprises a liquid crystal medium according to claim 4.

25. A component for high-frequency technology, which comprises a liquid crystal medium according to claim 10.

26. A component for high-frequency technology, which comprises a liquid crystal medium according to claim 11.

27. A component for high-frequency technology, which comprises a liquid crystal medium according to claim 12.

28. A component for high-frequency technology, which comprises a liquid crystal medium according to claim 13.

29. A component for high-frequency technology, which comprises a liquid crystal medium according to claim 14.

30. A component for high-frequency technology, which comprises a liquid crystal medium according to claim 15.

31. A component for high-frequency technology, which comprises a liquid crystal medium according to claim 16.

32. A component for high-frequency technology, which comprises a liquid crystal medium according to claim 17.

33. A component for high-frequency technology, which comprises a liquid crystal medium according to claim 18.

34. A component for high-frequency technology, which comprises a liquid crystal medium according to claim 19.

35. A component for high-frequency technology, which comprises a liquid crystal medium according to claim 20.

36. A component for high-frequency technology, which comprises a liquid crystal medium according to claim 21.

37. A component for high-frequency technology, which is a phase shifter, varactor, wireless or radio wave antenna array, or matching circuit adaptive filter, which comprises a liquid crystal medium according to claim 1.

38. A component for high-frequency technology, which comprises a cell containing a liquid crystal medium according to claim 1.

39. A liquid-crystal medium according to claim 1, wherein the liquid-crystal medium comprises at least one compound of the formula I wherein X.sup.12 is NCS, at least one compound of the formula II wherein X.sup.22 is NCS, or at least one compound of the formula III wherein X.sup.32 is NCS.

40. A liquid-crystal medium according to claim 1, wherein the liquid-crystal medium comprises at least one compound of the formula I wherein X.sup.12 is NCS or at least one compound of the formula II wherein X.sup.22 is NCS.

41. A component for high-frequency technology, which comprises a liquid crystal medium according to claim 39.

42. A component for high-frequency technology, which comprises a liquid crystal medium according to claim 40.

43. A liquid-crystal medium according to claim 1, wherein the total concentration of compounds of formula I in the liquid crystal medium is 20-40% by weight and the total concentration of compounds of formula II in the liquid crystal medium is 40-70% by weight.

44. A liquid-crystal medium according to claim 1, wherein the total concentration of compounds of formula I in the liquid crystal medium is 25-35% by weight and the total concentration of compounds of formula II in the liquid crystal medium is 40-70% by weight.

45. The liquid-crystal medium according to claim 1, wherein the total concentration of compounds of formulae I, II and III in the liquid crystal medium is 60% by weight or more.

46. The liquid-crystal medium according to claim 1, which additionally comprises one or more compounds of the following formulae: ##STR00175## in which n denotes an integer in the range from 0 to 7.

47. The liquid-crystal medium according to claim 4, which additionally comprises one or both of the following compounds: ##STR00176##

48. The liquid-crystal medium according to claim 4, which comprises one or more compounds of the formula I-2 which are selected from compounds of the following formulae: ##STR00177##

49. The liquid-crystal medium according to claim 1, which comprises one or more compounds of the formula II which are selected from compounds of the following formulae: ##STR00178##

50. The liquid-crystal medium according to claim 1, which comprises one or more compounds of the formula III which are selected from compounds of the following formulae: ##STR00179## in which: X.sup.32 denotes H, F, Cl, CN, NCS, SF.sub.5, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms or fluorinated alkenyl, unfluorinated or fluorinated alkenyloxy or unfluorinated or fluorinated alkoxyalkyl having 2 to 7 C atoms, R.sup.31 has the meaning indicated in claim 1, n denotes 1 to 7, and z denotes 0, 1, 2, 3 or 4, ##STR00180## in which R.sup.31 and R.sup.32 has the meaning indicated in claim 1, n and m, independently of one another, denote an integer in the range from 0 to 15, and z denotes 0, 1, 2, 3 or 4.

Description

EXAMPLES

(1) The following examples illustrate the present invention without limiting it in any way.

(2) However, it is clear to the person skilled in the art from the physical properties what properties can be achieved and in what ranges they can be modified. In particular, the combination of the various properties which can preferably be achieved is thus well defined for the person skilled in the art.

Example 1

(3) A liquid-crystal mixture M-1 having the composition and properties as indicated in the following table is prepared.

(4) TABLE-US-00007 Composition Compound No. Abbreviation 1 GGP-5-CL 26.0 2 PGIGI-3-CL 8.0 3 PGIGI-5-CL 20.0 4 PGIGI-5-F 9.0 5 PPTY-3-4 3.0 6 PYGP-3-5 5.0 7 PYGP-5-3 5.0 8 CGPC-3-5 3.0 9 CGPC-5-5 5.0 10 CPGP-5-2 8.0 11 CPGP-5-3 8.0 100.0 Physical properties T(N, I) = 171 C. n.sub.e (20 C., 589.3 nm) = 1.7859 n (20 C., 589.3 nm) = 0.2954 .sub.|| (20 C., 1 kHz) = 6.4 (20 C., 1 kHz) = 2.0 .sub.1 (20 C.) = 650 mPa .Math. s

(5) This mixture is very highly suitable for applications in the microwave range, in particular for phase shifters.

(6) TABLE-US-00008 TABLE 1 Properties of mixture M-1 at 30 GHz T/ C. .sub.r, .sub.r, || tan .sub. r, tan .sub. r, || .sub. r 11.27 2.40 2.97 0.0109 0.0026 0.19 17.45 29.71 2.41 2.97 0.0159 0.0037 0.19 11.70 58.28 2.41 2.97 0.0252 0.0061 0.18 7.07 87.50 2.40 2.89 0.0372 0.0097 0.17 4.51 Note: at 20 C., the following is obtained approximately by intrapolation: .sub.r = 0.56, tan .sub. r, = 0.013 and = 14.5.

(7) For comparison, the compound 4-pentyl-4-cyanobiphenyl (also called 5CB or K15, Merck KGaA) gives tan .sub.r,=0.026 and =4.3 at 20 C.

(8) TABLE-US-00009 TABLE 2 Comparison of the properties at 30 GHz and 20 C. Example Liquid crystal .sub.r .sub. r, 1 M-1 0.56 0.013 14.5 2 M-2 0.56 0.014 15 Comparison 5CB 0.026 4.3

Example 2

(9) A liquid-crystal mixture M-2 having the composition and properties as indicated in the following table is prepared.

(10) TABLE-US-00010 Composition Compound No. Abbreviation 1 GGP-5-CL 26.0 2 PGIGI-3-CL 8.0 3 PGIGI-5-CL 20.0 4 PGIGI-5-F 5.0 5 PPTY-3-4 3.0 6 PYGP-4-4 4.0 7 PYGP-5-3 5.0 8 CCZPC-3-5 3.0 9 CGPC-3-5 3.0 10 CGPC-5-5 5.0 11 CPGP-5-2 8.0 12 CPGP-5-3 8.0 100.0 Physical properties T(N, I) = 179.5 C. n.sub.e (20 C., 589.3 nm) = 1.7861 n (20 C., 589.3 nm) = 0.3118

(11) This mixture is very highly suitable for applications in the microwave range, in particular for phase shifters.

(12) TABLE-US-00011 TABLE 3 Properties of mixture M-2 at 30 GHz T/ C. .sub.r, .sub.r, || tan .sub. r, tan .sub. r, || .sub. r FoM 11.49 2.41 2.98 0.0108 0.0028 0.19 17.77 20.29 2.42 2.98 0.0130 0.0033 0.19 14.50 25.02 2.42 2.97 0.0143 0.0035 0.19 13.08 29.80 2.42 2.97 0.0155 0.0038 0.19 11.99 34.55 2.42 2.96 0.0169 0.0041 0.18 10.95 58.29 2.41 2.93 0.0246 0.0062 0.18 7.20 77.56 2.40 2.90 0.0319 0.0087 0.17 5.36 97.57 2.40 2.86 0.0406 0.0116 0.16 4.00 Note: at 20 C., the following is obtained approximately by intrapolation: .sub.r = 0.56, tan .sub. r, = 0.014 and = 15.

Example 3

(13) A liquid-crystal mixture M-3 having the composition and properties as indicated in the following table is prepared.

(14) TABLE-US-00012 Composition Compound No. Abbreviation 1 GGP-3-CL 10.0 2 GGP-5-CL 20.0 3 PPTUI-3-2 20.0 4 PPTUI-3-4 20.0 5 PPTUI-4-4 16.0 6 CPGP-5-2 7.0 7 CPGP-5-3 7.0 100.0 Physical properties T(N, I) = 170.1 C. n.sub.e (20 C., 589.3 nm) = 1.5267 n (20 C., 589.3 nm) = 0.2918 .sub.|| (20 C., 1 kHz) = 7.8 (20 C., 1 kHz) = 4.4 .sub.1 (20 C.) = 698 mPa .Math. s

(15) This mixture is very highly suitable for applications in the microwave range, in particular for phase shifters.

Example 4

(16) A liquid-crystal mixture M-4 having the composition and properties as indicated in the following table is prepared.

(17) TABLE-US-00013 Composition Compound No. Abbreviation 1 GGP-3-CL 10.0 2 GGP-5-CL 19.0 3 PPTUI-3-2 18.0 4 PPTUI-3-4 18.0 5 PPTUI-4-4 10.0 6 PGIGP-3-5 6.00 7 PPGU-3-F 3.00 8 CPGP-5-2 8.0 9 CPGP-5-3 8.0 100.0 Physical properties T(N, I) = 183.5 C. n (20 C., 589.3 nm) = 0.283 .sub.|| (20 C., 1 kHz) = 8.0 (20 C., 1 kHz) = 3.5 .sub.1 (20 C.) = 753 mPa .Math. s

(18) This mixture is very highly suitable for applications in the microwave range, in particular for phase shifters.

Example 5

(19) A liquid-crystal mixture M-5 having the composition and properties as indicated in the following table is prepared.

(20) TABLE-US-00014 Composition Compound No. Abbreviation 1 GGP-3-CL 10.0 2 GGP-5-CL 17.0 3 PPTUI-3-2 13.0 4 PPTUI-3-4 13.0 5 PPTUI-4-4 10.0 6 PPGU-3-F 3.0 7 PPGU-4-F 3.0 8 PPGU-V2-F 3.0 9 PGIGP-3-5 7.0 10 PGIGP-5-5 7.0 11 CPGP-5-2 7.0 12 CPGP-5-3 7.0 100.0 Physical properties

(21) This mixture is very highly suitable for applications in the microwave range, in particular for phase shifters.

Example 6

(22) A liquid-crystal mixture M-6 having the composition and properties as indicated in the following table is prepared.

(23) TABLE-US-00015 Composition Compound No. Abbreviation 1 GGP-5-CL 17.0 2 PPTUI-3-2 20.0 3 PPTUI-3-4 20.0 4 PPTUI-4-4 10.0 5 PPGU-3-F 3.0 6 PPGU-4-F 3.0 7 PPGU-V2-F 3.0 8 PGIGP-3-4 5.0 9 PGIGP-3-5 5.0 10 CPGP-5-2 7.0 11 CPGP-5-3 7.0 100.0 Physical properties T(N, I) = 198.0 C. .sub.|| (20 C., 1 kHz) = 7.7 (20 C., 1 kHz) = 3.5

(24) This mixture is very highly suitable for applications in the microwave range, in particular for phase shifters.

Example 7

(25) A liquid-crystal mixture M-7 having the composition and properties as indicated in the following table is prepared.

(26) TABLE-US-00016 Composition Compound No. Abbreviation 1 GGP-3-CL 10.0 2 GGP-5-CL 20.0 3 PPTUI-3-2 15.0 4 PPTUI-3-4 20.0 5 PPGU-3-F 3.0 6 PPGU-4-F 3.0 7 PPGU-V2-F 3.0 8 PGIGP-3-4 5.0 9 PGIGP-3-5 5.0 10 CPGP-5-2 8.0 11 CPGP-5-3 8.0 100.0 Physical properties T(N, I) = 193.0 C. .sub.|| (20 C., 1 kHz) = 8.7 (20 C., 1 kHz) = 3.5

(27) This mixture is very highly suitable for applications in the microwave range, in particular for phase shifters.

Example 8

(28) A liquid-crystal mixture M-8 having the composition and properties as indicated in the following table is prepared.

(29) TABLE-US-00017 Composition Compound No. Abbreviation 1 GGP-3-CL 10.0 2 GGP-5-CL 19.0 3 PPTUI-3-2 18.0 4 PPTUI-3-4 18.0 5 PPTUI-4-4 10.0 6 PPGU-3-F 2.0 7 PPGU-4-F 2.0 8 PPGU-V2-F 2.0 9 PGIGP-3-5 5.0 10 CPGP-5-2 7.0 11 CPGP-5-3 7.0 100.0 Physical properties

(30) This mixture is very highly suitable for applications in the microwave range, in particular for phase shifters.

Example 9

(31) A liquid-crystal mixture M-9 having the composition and properties as indicated in the following table is prepared.

(32) TABLE-US-00018 Composition Compound No. Abbreviation 1 PGP-2-5 10.0 2 PGP-3-4 10.0 3 PGP-3-7 15.0 4 PGP-2-2V 5.0 5 PYP-2-2V 10.0 6 PYP-2-4 10.0 7 PYP-2-5 20.0 8 PYP-3-5 15.0 9 PGIGP-3-5 5.0 100.0 Physical properties

(33) This mixture is very highly suitable for applications in the microwave range, in particular for phase shifters.

Example 10

(34) A liquid-crystal mixture M-10 having the composition and properties as indicated in the following table is prepared.

(35) TABLE-US-00019 Composition Compound No. Abbreviation 1 GGP-3-F 10.0 2 GGP-5-F 10.0 3 GGP-3-CL 10.0 4 GGP-4-CL 20.0 5 GGP-5-CL 20.0 6 GGP-6-CL 10.0 7 GGPP-5-3 5.0 8 PGGP-3-5 5.0 9 PGGP-3-6 5.0 10 PGGP-5-3 5.0 100.0 Physical properties T(N, I) = 134.5 C. n.sub.e (20 C., 589.3 nm) = 1.8036 n (20 C., 589.3 nm) = 0.2774 .sub.|| (20 C., 1 kHz) = 15.2 (20 C., 1 kHz) = 10.2 .sub.1 (20 C.) = 758 mPa .Math. s

(36) This mixture is very highly suitable for applications in the microwave range, in particular for phase shifters.

Example 11

(37) A liquid-crystal mixture M-11 having the composition and properties as indicated in the following table is prepared.

(38) TABLE-US-00020 Composition Compound No. Abbreviation 1 GGP-3-F 5.0 2 GGP-3-CL 10.0 3 GGP-4-CL 10.0 4 GGP-5-CL 15.0 5 GGP-5-3 20.0 6 PGP-2-5 10.0 7 PGP-3-7 15.0 8 PGP-2-2V 10.0 9 PGGP-3-5 5.0 100.0 Physical properties n.sub.e (20 C., 589.3 nm) = 1.7885 n (20 C., 589.3 nm) = 0.2640 .sub.|| (20 C., 1 kHz) = 8.8 (20 C., 1 kHz) = 4.7 .sub.1 (20 C.) = 660 mPa .Math. s

(39) This mixture is very highly suitable for applications in the microwave range, in particular for phase shifters.

Example 12

(40) A liquid-crystal mixture M-12 having the composition and properties as indicated in the following table is prepared.

(41) TABLE-US-00021 Composition Compound No. Abbreviation 1 GGP-3-CL 10.0 2 GGP-4-CL 20.0 3 GGP-5-CL 20.0 4 GGP-6-CL 10.0 5 GGP-5-3 25.0 6 PGGP-3-5 5.0 7 PGGP-3-6 5.0 8 PGGP-5-3 5.0 100.0 Physical properties T(N, I) = 124.5 C. n.sub.e (20 C., 589.3 nm) = 1.7951 n (20 C., 589.3 nm) = 0.2709 .sub.|| (20 C., 1 kHz) = 11.6 (20 C., 1 kHz) = 6.8 .sub.1 (20 C.) = 895 mPa .Math. s

(42) This mixture is very highly suitable for applications in the microwave range, in particular for phase shifters.

Example 13

(43) A liquid-crystal mixture M-13 having the composition and properties as indicated in the following table is prepared.

(44) TABLE-US-00022 Composition Compound No. Abbreviation 1 GGP-3-CL 5.0 2 GGP-5-CL 19.0 3 PGU-7-F 2.0 4 PPTUI-3-2 18.0 5 PPTUI-3-4 18.0 6 PPTUI-4-4 10.0 7 PPGU-7-F 2.0 8 PGIGP-3-5 6.0 9 DPGU-3-F 2.0 10 DPGU-3-OT 2.0 11 CPGP-5-2 8.0 12 CPGP-5-3 8.0 100.0 Physical properties T(N, I) = 184.5 C.

(45) This mixture is very highly suitable for applications in the microwave range, in particular for phase shifters.

(46) TABLE-US-00023 TABLE 4 Properties of mixture M-13 at 30 GHz T/ C. .sub.r, .sub.r, || tan .sub. r, tan .sub. r, || .sub. r 9.47 2.51 2.92 0.0094 0.0035 0.140 15.0 19.67 2.51 2.92 0.0115 0.0041 0.139 12.1 30.07 2.49 2.94 0.0135 0.0046 0.152 11.2 40.52 2.44 2.96 0.0169 0.0046 0.175 10.3 50.17 2.36 2.96 0.0214 0.0050 0.204 9.48 59.99 2.34 2.94 0.0246 0.0056 0.204 8.24 70.41 2.34 2.93 0.0276 0.0061 0.199 7.22 79.74 2.35 2.91 0.0291 0.0067 0.195 6.69 84.52 2.35 2.91 0.0295 0.0071 0.192 6.51 Note: at 20 C., the following is obtained approximately by intrapolation: .sub.r = 2.51, tan .sub. r, = 0.0115, .sub. r = 0.140 and = 14.5.

Example 14

(47) A liquid-crystal mixture M-14 having the composition and properties as indicated in the following table is prepared.

(48) TABLE-US-00024 Composition Compound No. Abbreviation 1 GGP-5-CL 20.0 2 PGU-3-CL 2.0 3 PGU-4-OT 2.0 4 PGP-F-OT 3.0 5 PPTUI-3-2 13.0 6 PPTUI-3-4 15.0 7 PPTUI-4-4 20.0 8 PPGU-7-F 2.0 9 PGIGP-3-5 6.0 10 CPTP-3-2 3.0 11 DPGU-3-F 2.0 12 DPGU-3-OT 2.0 13 CPGP-5-2 4.0 14 CPGP-5-3 6.0 100.0 Physical properties T(N, I) = 175.5 C.

(49) This mixture is very highly suitable for applications in the microwave range, in particular for phase shifters.

Example 15

(50) A liquid-crystal mixture M-15 having the composition and properties as indicated in the following table is prepared.

(51) TABLE-US-00025 Composition Compound No. Abbreviation 1 GGP-5-CL 10.0 2 GGP-6-CL 5.0 3 PGP-3-2V 3.0 4 PGP-2-2V 3.0 5 PPTUI-3-2 15.0 6 PPTUI-3-4 18.0 7 PPTUI-4-4 21.0 8 PPGU-7-F 2.0 9 PPGU-V2-F 2.0 10 PGIGP-3-5 7.0 11 CPTP-3-2 4.0 12 CPGU-3-OT 2.0 13 CPGU-4-OT 2.0 14 DPGU-3-OT 2.0 15 CPGP-5-2 4.0 100.0 Physical properties T(N, I) = 178 C.

(52) This mixture is very highly suitable for applications in the microwave range, in particular for phase shifters.

Example 16

(53) A liquid-crystal mixture M-16 having the composition and properties as indicated in the following table is prepared.

(54) TABLE-US-00026 Composition Compound No. Abbreviation 1 GGP-5-CL 20.0 2 GGP-5-3 12.0 3 PPTUI-3-2 12.0 4 PPTUI-3-4 16.0 5 PPTUI-4-4 20.0 6 PGUQU-5-F 5.0 7 PGGP-3-5 5.0 8 PGGP-3-6 4.0 9 APGP-3-3 3.0 10 APGP-3-4 3.0 100.0 Physical properties T(N, I) = 159.5 C. .sub.|| (20 C., 1 kHz) = 7.9 (20 C., 1 kHz) = 4.3 .sub.1 (20 C.) = 686 mPa .Math. s

(55) This mixture is very highly suitable for applications in the microwave range, in particular for phase shifters.

Example 17

(56) A liquid-crystal mixture M-17 having the composition and properties as indicated in the following table is prepared.

(57) TABLE-US-00027 Composition Compound No. Abbreviation 1 GGP-5-3 10.0 2 PPTUI-3-F 8.0 3 PPTUI-4-F 8.0 4 PPTUI-3-2 12.0 5 PPTUI-3-4 16.0 6 PPTUI-4-4 20.0 7 PPTUI-3-A4 5.0 8 PGUQU-5-F 7.0 9 PGGP-3-5 4.0 10 PGGP-3-6 4.0 11 APGP-3-3 3.0 12 APGP-3-4 3.0 100.0 Physical properties T(N, I) = 169 C.

(58) This mixture is very highly suitable for applications in the microwave range, in particular for phase shifters.