Liquid-crystalline medium and high-frequency components comprising same

1. A liquid-crystal medium, comprising

one or more polymerisable compounds of formula P

P a -(Sp a ) s1 -(A 1 -Z 1 ) n1 -A 2 -Q-A 3 -(Z 4 -A 4 ) n2 -(Sp b ) s2 -P b   P

wherein

P a , P b each, independently of one another, are a polymerisable group,

Sp a , Sp b each, independently of one another, denote a spacer group,

s1, s2 each, independently of one another, denote 0 or 1,

n1, n2 each, independently of one another, denote 0 or 1,

Q denotes a single bond, —CF 2 O—, —OCF 2 —, —CH 2 O—, —OCH 2 —, —(CO)O—, —O(CO)—, —(CH 2 ) 4 —, —CH 2 CH 2 —, —CF 2 —CF 2 —, —CF 2 —CH 2 —, —CH 2 —CF 2 —, —CH═CH—, —CF═CF—, —CF═CH—, —(CH 2 ) 3 O—, —O(CH 2 ) 3 —, —CH═CF—, —C≡C—, —O—, —CH 2 —, —(CH 2 ) 3 —, or —CF 2 —,

Z 1 , Z 4 independently of one another, denote a single bond, —CF 2 O—, —OCF 2 —, —CH 2 O—, —OCH 2 —, —(CO)O—, —O(CO)—, —(CH 2 ) 4 —, —CH 2 CH 2 —, —CF 2 —CF 2 —, —CF 2 —CH 2 —, —CH 2 —CF 2 —, —CH═CH—, —CF═CF—, —CF═CH—, —(CH 2 ) 3 O—, —O(CH 2 ) 3 —, —CH═CF—, —C≡C—, —O—, —CH 2 —, —(CH 2 ) 3 —, or —CF 2 —,

where Z 1 and Q or Z 4 and Q do not simultaneously denote a group selected from —CF 2 O— and —OCF 2 —,

A 1 , A 2 , A 3 , A 4 ,

each, independently of one another, denote

a) trans-1,4-cyclohexylene, 1,4-cyclohexenylene or 1,4′-bicyclohexylene, in which one or more non-adjacent CH 2 groups are optionally replaced by —O— and/or —S— and in which one or more H atoms are optionally replaced by F,

b) 1,4-phenylene or 1,3-phenylene, in which one or two CH groups are optionally replaced by N and in which one or more H atoms are optionally replaced by L,

c) tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, tetrahydrofuran-2,5-diyl, cyclobutane-1,3-diyl, piperidine-1,4-diyl, thiophene-2,5-diyl or selenophene-2,5-diyl, each of which is optionally mono- or polysubstituted by L,

d) saturated, partially unsaturated or fully unsaturated, and optionally substituted, polycyclic radicals having 5 to 20 cyclic C atoms, one or more of which are optionally replaced by heteroatoms,

and A 3 , alternatively may be a single bond,

L on each occurrence, identically or differently, denotes F, Cl, CN, SCN, SF 5 or straight-chain or branched, in each case optionally fluorinated, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms, and

one or more compounds of formulae I, II or III

in which

L 11 denotes R 11 or X 11 ,

L 12 denotes R 12 or X 12 ,

R 11 and R 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 11 and X 12 , independently of one another, denote H, F, Cl, —CN, —NCS, —SF 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

independently of one another, denote

in which

L 21 denotes R 21 and, in the case where Z 21 and/or Z 22 denote trans-CH═CH— or trans-CF═CF—, alternatively denotes X 21 ,

L 22 denotes R 22 and, in the case where Z 21 and/or Z 22 denote trans-CH═CH— or trans-CF═CF—, alternatively denotes X 22 ,

R 21 and R 22 , independently of one another, denote H, unfluorinated alkyl or unfluorinated alkoxy having 1 to 17, or unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to 15,

X 21 and X 22 , independently of one another, denote F, Cl, —CN, —NCS, —SF 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 21 and Z 22

denotes trans-CH═CH—, trans-CF═CF— or —C≡C— and the other, independently thereof, denotes trans-CH═CH—, trans-CF═CF— or a single bond, and

independently of one another, denote

in which

L 31 denotes R 31 or X 31 ,

L 32 denotes R 32 or X 32 ,

R 31 and R 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 31 and X 32 , independently of one another, denote H, F, Cl, —CN, —NCS, —SF 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 31 to Z 33 , independently of one another, denote trans-CH═CH—, trans —CF═CF—, —C≡C— or a single bond, and

independently of one another, denote

and wherein the liquid-crystal medium has a clearing point of 90° C. or more.

2. The liquid-crystal medium according to claim 1 , which comprises one or more mono-reactive polymerisable compounds and/or one or more direactive polymerisable compounds.

3. The liquid-crystal medium according to claim 2 , which comprises one or more mono-reactive polymerisable compounds which are methacrylates and/or one or more direactive polymerisable compounds which are bisacrylates or mixed acrylate methacrylates.

4. The liquid-crystal medium according to claim 1 , which comprises one or more compounds of formula I.

5. The liquid-crystal medium according to claim 1 , which comprises one or more compounds of formula II.

6. The liquid-crystal medium according to claim 1 , which comprises one or more compounds of formula III.

7. The liquid-crystal medium according to claim 1 , which additionally comprises a polymerisation initiator which is a UV- or thermo initiator.

8. A method for stabilizing the liquid-crystal medium according to claim 1 , comprising polymerising the polymerisable compounds therein.

9. A composite system comprising a polymer obtained or obtainable from the polymerisation of the polymerisable compounds in the liquid-crystal medium according to claim 1 .

10. A component for high-frequency technology, which comprises the liquid-crystal medium according to claim 1 or a composite system comprising a polymer obtained or obtainable from the polymerisation of the polymerisable compounds in said liquid-crystal medium.

11. The component according to claim 10 , which is suitable for operation in the microwave range.

12. The component according to claim 10 , which is a phase shifter or a LC based antenna element operable in the microwave region.

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

14. A microwave antenna array, comprising one or more components according to claim 10 .

15. The liquid-crystal medium according to claim 1 , wherein

A 1 , A 2 , A 3 , A 4 ,

each, independently of one another, denote

a) trans-1,4-cyclohexylene, 1,4-cyclohexenylene or 1,4′-bicyclohexylene, in which one or more non-adjacent CH 2 groups are optionally replaced by —O— and/or —S— and in which one or more H atoms are optionally replaced by F,

b) 1,4-phenylene or 1,3-phenylene, in which one or two CH groups are optionally replaced by N and in which one or more H atoms are optionally replaced by L,

c) tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, tetrahydrofuran-2,5-diyl, cyclobutane-1,3-diyl, piperidine-1,4-diyl, thiophene-2,5-diyl or selenophene-2,5-diyl, each of which is optionally mono- or polysubstituted by L

d) bicyclo[1.1.1]pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl, spiro[3.3]heptane-2,6-diyl,

in which one or more H atoms are optionally replaced by L, and/or one or more double bonds are optionally replaced by single bonds, and/or one or more CH groups are optionally replaced by N,

L on each occurrence, identically or differently, denotes F, Cl, CN, SCN, SF 5 or straight-chain or branched, in each case optionally fluorinated, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms,

R 03 , R 04 each, independently of one another, denote H, F or straight-chain or branched alkyl having 1 to 12 C atoms, in which one or more H atoms are optionally replaced by F,

M denotes —O—, —S—, —CH 2 —, —CHY 1 — or —CY 1 Y 2 —, and

Y 1 and Y 2 each, independently of one another, denote H, F, Cl, CN or CF 3 , and one of the groups Y 1 and Y 2 alternatively denotes —OCF 3 ,

and A 3 alternatively may be a single bond.

16. The liquid-crystal medium according to claim 1 , wherein the compound of formula I is a compound of one of the following formulae

in which

have the meanings given for the compound of formula I,

R 11 denotes unfluorinated alkyl having 1 to 7 C atoms or unfluorinated alkenyl having 2 to 7 C atoms,

R 12 denotes unfluorinated alkyl having 1 to 7 C atoms or unfluorinated alkenyl having 2 to 7 C atoms or unfluorinated alkoxy having 1 to 7 C atoms,

X 11 and X 12 independently of one another, denote F, Cl, —OCF 3 , —CF 3 , —CN, —NCS or —SF 5 .

17. The liquid-crystal medium according to claim 1 , wherein the compound of formula II is a compound of one of the following formulae

in which

Z 21 and Z 22 denote trans-CH═CH— or trans-CF═CF—,

R 21 and R 22 independently of one another, denote H, unfluorinated alkyl or alkoxy having 1 to 7 C atoms or unfluorinated alkenyl having 2 to 7 C atoms,

X 22 denotes F, Cl, —CN or —NCS,

and one of

denotes

and the others, independently of one another, denote

18. The liquid-crystal medium according to claim 1 , wherein the compound of formula III is a compound of one of the following formulae

wherein

Y 31 and Y 32 denotes H or F,

R 31 denotes unfluorinated alkyl or alkoxy, each having 1 to 7 C atoms, or unfluorinated alkenyl having 2 to 7 C atoms,

R 32 denotes unfluorinated alkyl or alkoxy, each having 1 to 7 C atoms, or unfluorinated alkenyl having 2 to 7 C atoms, and

X 32 denotes F, Cl, or —OCF 3 .

19. The liquid-crystal medium according to claim 1 , wherein the compound of formula P is a compound of one of the following formulae

wherein

L on each occurrence, identically or differently, denotes F, Cl, CN, SCN, SF 5 or straight-chain or branched, in each case optionally fluorinated, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms,

r denotes 0, 1, 2, 3 or 4,

s denotes 0, 1, 2 or 3, and

n denotes an integer between 1 and 24.

20. The liquid-crystal medium according to claim 1 , wherein the compound of formula P is a compound of one of the following formulae

wherein P a , P b , Sp a , Sp b , s1 and s2 are as defined for the compound of formula P.

21. The liquid-crystal medium according to claim 1 , which has a clearing point of 120° C. or more.