Liquid crystal mixtures

Claim 2

A nematic liquid crystal mixture having positive anisotropy of the dielectric constants which comprises a nematogenic mixture with a clearing point above 60° C. and one or more solvents individually selected from the group consisting of a straight-chain alkane of 8-16 carbon atoms, an alkyl halide of 6-16 carbon atoms, a dialkyl ether of 4-8 carbon atoms in each alkyl radical, a dialkyl carbonate of 2-7 carbon atoms in each alkyl radical, an alkanecarboxylic acid alkyl ester the alkyl radicals of which together contain 6-16 carbon atoms p-xylene, 1-phenylheptane, p-octylbenzoic acid methyl ester, and p-hexylbenzaldehyde.

Claim 3

A liquid crystal mixture, in accordance with claim 1, which contains 0.5% to 15% of solvent or solvent mixture.

Claim 4

A liquid crystal mixture, in accordance with claim 1, which contains 0.5% to 10% of solvent or solvent mixture.

Claim 5

A liquid crystal mixture, in accordance with claim 1, which contains 3% to 8% of solvent or solvent mixture.

Claim 6

A liquid crystal mixture, in accordance with claim 2, wherein the solvent is a dialkyl ether the alkyl radicals of which together contain 4-8 carbon atoms in each alkyl radical or an alkanecarboxylic acid alkyl ester of 6-16 carbon atoms.

Claim 7

A liquid crystal mixture, in accordance with claim 2, wherein the solvent is dibutyl ether, dihexyl ether, dioctyl ether, butyric acid propyl ester or butyric acid pentyl ester.

Claim 8

A liquid crystal mixture, in accordance with claim 1, in which the nematogenic mixture comprises two or more compounds selected from the group consisting of compounds of the formulas ##STR24## wherein R 1 is straight-chain alkyl containing 2 to 8 carbon atoms, straight-chain alkoxy containing 4 to 7 carbon atoms, straight-chain alkanoyloxy containing 2 to 8 carbon atoms or straight-chain alkylcarbonate containing 2 to 11 carbon atoms; ##STR25## wherein R 2 is straight-chain alkyl containing 4 to 7 carbon atoms or straight-chain alkylcarbonate containing 2 to 11 carbon atoms; ##STR26## wherein R 3 is straight-chain alkyl containing 4 to 8 carbon atoms, straight-chain alkoxy containing 5 to 8 carbon atoms, straight-chain alkanoyloxy containing 2 to 8 carbon atoms or straight-chain alkylcarbonate containing 3 to 11 carbon atoms; ##STR27## wherein R 4 is straight-chain alkyl containing 4 to 8 carbon atoms, straight-chain alkoxy containing 4 to 8 carbon atoms, straight-chain alkanoyloxy containing 4 to 9 carbon atoms or straight-chain alkylcarbonate containing 4 to 11 carbon atoms; ##STR28## wherein R 5 is straight-chain alkyl containing 1 to 8 carbon atoms; ##STR29## wherein one of R 6 and R 7 is cyano and the other is straight-chain alkyl containing 3 to 9 carbon atoms, straight-chain alkoxy containing 2 to 9 carbon atoms or straight-chain alkanoyloxy containing 2 to 9 carbon atoms; ##STR30## wherein one of R 8 and R 9 is hydrogen, straight-chain alkyl containing 1 to 7 carbon atoms, straight-chain alkoxy containing 1 to 7 carbon atoms or straight-chain alkanoyloxy containing 2 to 7 carbon atoms and the other is cyano and one of X, Y and Z is nitrogen and the other two are CH; ##STR31## wherein R''' is straight-chain alkyl containing 3 to 8 carbon atoms.

Claim 9

A liquid crystal mixture, in accordance with claim 1, which consists of p-n-butylbenzoic acid p'-cyanophenyl ester, p-n-hexylbenzoic acid p'-cyanophenyl ester, p-n-octylbenzoic acid p'-cyanophenyl ester, methylhydroquinone di-p-n-butylbenzoate and dihexyl ether.

Claim 10

A liquid crystal mixture, in accordance with claim 1, which consists of 25% p-n-butylbenzoic acid p'-cyanophenyl ester, 25% p-n-hexylbenzoic acid p'-cyanophenyl ester, 25% p-n-octylbenzoic acid p'-cyanophenyl ester, 25% methylhydroquinone di-p-n-butylbenzoate and 6% dihexyl ether.

Claim 11

A liquid crystal mixture, in accordance with claim 1, which consists of p-n-butylbenzoic acid p'-cyanophenyl ester, p-n-hexylbenzoic acid p'-cyanophenyl ester, p-n-octylbenzoic acid p'-cyanophenyl ester, methylhydroquinone di-p-n-butylbenzoate and decane.

Claim 12

A liquid crystal mixture, in accordance with claim 1, which consists of 25% p-n-butylbenzoic acid p'-cyanophenyl ester, 25% p-n-hexylbenzoic acid p'-cyanophenyl ester, 25% p-n-octylbenzoic acid p'-cyanophenyl ester, 25% methylhydroquinone di-p-n-butylbenzoate and 6% decane.

Claim 13

A liquid crystal mixture, in accordance with claim 1, which consists of p-n-butylbenzoic acid p'-cyanophenyl ester, p-n-pentylbenzoic acid p'-cyanophenyl ester, p-n-hexylbenzoic acid p'-cyanophenyl ester, p-[(p-n-butylbenzylidene)-amino] benzonitrile, 5-n-pentyl-2-(4-cyanophenyl)pyrimidine, 5-n-heptyl-2-(4-cyanophenyl)pyrimidine, 2-(4-cyanophenyl)-5-(4-n-butylphenyl)pyrimidine and dihexyl ether.

Claim 14

A liquid crystal mixture, in accordance with claim 1, which consists of 7.7% p-n-butylbenzoic acid p'-cyanophenyl ester, 8.1% p-n-pentylbenzoic acid p'-cyanophenyl ester, 10.0% p-n-hexylbenzoic acid p'-cyanophenyl ester, 36.0% p-[(p-n-butylbenzylidene)-amino]-benzonitrile, 8.4% 5-n-pentyl-2-(4-cyanophenyl)-pyrimidine, 15.8% 5-n-heptyl-2-(4-cyanophenyl)pyrimidine, 13.0% 2-(4-cyanophenyl)-5-(4-n-butylphenyl)pyrimidine and 6% dihexyl ether.

Claim 15

A liquid crystal mixture, in accordance with claim 1, which consists of p-n-butylbenzoic acid p'-cyanophenyl ester, p-n-pentylbenzoic acid p'-cyanophenyl ester, p-n-hexylbenzoic acid p'-cyanophenyl ester, p-[(p-n-butylbenzylidene)-amino]benzonitrile, 5-n-pentyl-2-(4-cyanophenyl)pyrimidine, 5-n-heptyl-2-(4-cyanophenyl)-pyrimidine, 2-(4-cyanophenyl)-5-(4-n-butylphenyl)pyrimidine and butyric acid propyl ester.

Claim 16

A liquid crystal mixture, in accordance with claim 1, which consists of 7.7% p-n-butylbenzoic acid p'-cyanophenyl ester, 8.1% p-n-pentylbenzoic acid p'-cyanophenyl ester, 10.0% p-n-hexylbenzoic acid p'-cyanophenyl ester, 36% p-[(p-n-butylbenzylidene)amino]-benzonitrile, 8.4% 5-n-pentyl-2-(4-cyanophenyl)pyrimidine, 15.8% 5-n-heptyl-2-(4-cyanophenyl)pyrimidine, 13.0% 2-(4-cyanophenyl)-5-(4-n-butylphenyl)pyrimidine and 4% butyric acid propyl ester.

Claim 17

A liquid crystal mixture, in accordance with claim 1, which consists of p-n-butylbenzoic acid p'-cyanophenyl ester, p-n-pentylbenzoic acid p'-cyanophenyl ester, p-n-hexylbenzoic acid p'-cyanophenyl ester, p-n-heptylbenzoic acid p'-cyanophenyl ester, 5-n-pentyl-2-(4-cyanophenyl)pyrimidine, 5-n-heptyl-2-(4-cyanophenyl)pyrimidine, 2-(4-cyanophenyl)-5-(4-n-butylphenyl)pyrimidine and p-xylene.

Claim 18

A liquid crystal mixture, in accordance with claim 1, which consists of 10.3% p-n-butylbenzoic acid p'-cyanophenyl ester, 11.1% p-n-pentylbenzoic acid p'-cyanophenyl ester, 14.3% p-n-hexylbenzoic acid p'-cyanophenyl ester, 15.4% p-n-heptylbenzoic acid p'-cyanophenyl ester, 11.0% 5-n-pentyl-2-(4-cyanophenyl)pyrimidine, 21.2% 5-n-heptyl-2-(4-cyanophenyl)pyrimidine, 15.6% 2-(4-cyanophenyl)-5-(4-n-butylphenyl)pyrimidine and 7% p-xylene.

Claim 19

A liquid crystal mixture, in accordance with claim 1, which consists of 4'-n-pentyl-4-cyanobiphenyl, 4'-n-heptyl-4-cyanobiphenyl, 4'-heptyloxy-4-cyanobiphenyl, 2-(4-cyanophenyl)-5-(4-n-propylphenyl)pyrimidine, 2-(4-cyanophenyl)-5-(4-n-butylphenyl)-pyrimidine, 4-cyano-4"-n-pentyl-p-terphenyl and dihexyl ether.

Claim 20

A liquid crystal mixture, in accordance with claim 1, which consists of 46.8% 4'-n-pentyl-4-cyanobiphenyl, 23.4% 4'-n-heptyl-4-cyanobiphenyl, 7.8% 4'-n-heptyloxy-4-cyanobiphenyl, 2.3% 2-(4-cyanophenyl)-5-(4-n-propylphenyl)pyrimidine, 11.3% 2-(4-cyanophenyl)-5-(4-n-butylphenyl)pyrimidine, 7.7% 4-cyano-4"-n-pentyl-p-terphenyl and 6% dihexyl ether.

Claim 21

A nematic liquid crystal mixture having positive anisotropy of the dielectric constants which comprises a nematogenic mixture with a clearing point above 60° C. and one or more solvents individually selected from the group consisting of a straight-chain alkane of 8-16 carbon atoms, an alkyl halide of 6-16 carbon atoms, a dialkyl ether of 4-8 carbon atoms in each alkyl radical, a dialkyl carbonate of 2-7 carbon atoms in each alkyl radical, an alkanecarboxylic acid alkyl ester the alkyl radicals of which together contain 6-16 carbon atoms, p-xylene, 1-phenylheptane, p-octylbenzoic acid methyl ester, p-hexylbenzaldehyde, and a compound of the formula ##STR32## wherein R 14 and R 15 are straight-chain alkyl containing, together, a total of not more than 14 carbon atoms or R 14 is straight-chain alkyl and R 15 is straight-chain alkoxy containing, together, a total of not more than 8 carbon atoms, provided said nematogenic mixture contains at least one compound selected from the formula ##STR33## wherein one of R 8 and R 9 is hydrogen, straight-chain alkyl containing 1 to 7 carbon atoms, straight-chain alkoxy containing 1 to 7 carbon atoms or straight-chain alkanoyloxy containing 2 to 7 carbon atoms and the other is cyano and one of X, Y and Z is nitrogen and the other two are CH.

Claim 22

A nematic liquid crystal mixture having positive anisotropy of the dielectric constants which comprises a nematogenic mixture with a clearing point above 60° C. and one or more solvents individually selected from the group consisting of a straight-chain alkane of 8-16 carbon atoms, an alkyl halide of 6-16 carbon atoms, a dialkyl ether of 4-8 carbon atoms in each alkyl radical, a dialkyl carbonate of 2-7 carbon atoms in each alkyl radical, an alkanecarboxylic acid alkyl ester the alkyl radicals of which together contain 6-16 carbon atoms, p-xylene, 1-phenylheptane, p-octylbenzoic acid methyl ester, p-hexylbenzaldehyde, and a compound of the formula ##STR32## wherein R 14 and R 15 are straight-chain alkyl containing, together, a total of not more than 14 carbon atoms or R 14 is straight-chain alkyl and R 15 is straight-chain alkoxy containing, together, a total of not more than 8 carbon atoms, provided said nematogenic mixture contains at least one compound selected from the formula ##STR33## wherein one of R 8 and R 9 is hydrogen, straight-chain alkyl containing 1 to 7 carbon atoms, straight-chain alkoxy containing 1 to 7 carbon atoms or straight-chain alkanoyloxy containing 2 to 7 carbon atoms and the other is cyano and one of X, Y and Z is nitrogen and the other two are CH.

Claim 23

A nematic liquid crystal mixture, in accordance with claim 20, in which the nematogenic mixture comprises two or more compounds selected from the group consisting of compounds of the formulas ##STR34## wherein R 1 is straight-chain alkyl containing 2 to 8 carbon atoms, straight-chain alkoxy containing 4 to 7 carbon atoms, straight-chain alkanoyloxy containing 2 to 8 carbon atoms or straight-chain alkylcarbonate containing 2 to 11 carbon atoms; ##STR35## wherein R 2 is straight-chain alkyl containing 4 to 7 carbon atoms or straight-chain alkylcarbonate containing 2 to 11 carbon atoms; ##STR36## wherein R 3 is straight-chain alkyl containing 4 to 8 carbon atoms, straight-chain alkoxy containing 5 to 8 carbon atoms, straight-chain alkanoyloxy containing 2 to 8 carbon atoms or straight-chain alkylcarbonate containing 3 to 11 carbon atoms; ##STR37## wherein R 4 is straight-chain alkyl containing 4 to 8 carbon atoms, straight-chain alkoxy containing 4 to 8 carbon atoms, straight-chain alkanoyloxy containing 4 to 9 carbon atoms or straight-chain alkylcarbonate containing 4 to 11 carbon atoms; ##STR38## wherein R 5 is straight-chain alkyl containing 1 to 8 carbon atoms; ##STR39## wherein one of R 6 and R 7 is cyano and the other is straight-chain alkyl containing 3 to 9 carbon atoms, straight-chain alkoxy containing 2 to 9 carbon atoms or straight-chain alkanoyloxy containing 2 to 9 carbon atoms; ##STR40## wherein one of R 8 and R 9 is hydrogen, straight-chain alkyl containing 1 to 7 carbon atoms, straight-chain alkoxy containing 1 to 7 carbon atoms or straight-chain alkanoyloxy containing 2 to 7 carbon atoms and the other is cyano and one of X, Y and Z is nitrogen and the other two are CH; and ##STR41## wherein R''' is straight-chain alkyl containing 3 to 8 carbon atoms, provided said nematogenic mixture contains at least one compound selected from the formula ##STR42## wherein one of R 8 and R 9 is hydrogen, straight-chain alkyl containing 1 to 7 carbon atoms, straight-chain alkoxy containing 1 to 7 carbon atoms or straight-chain alkanoyloxy containing 2 to 7 carbon atoms and the other is cyano and one of X, Y and Z is nitrogen and the other two are CH.

Claim 24

A liquid crystal mixture, in accordance with claim 20, p-n-butylbenzoic acid p'-cyanophenyl ester, p-n-pentylbenzoic acid p'-cyanophenyl ester, p-n-hexylbenzoic acid p'-cyanophenyl ester, p-n-heptylbenzoic acid p'-cyanophenyl ester, 5-n-pentyl-2-(4-cyanophenyl)-pyrimidine, 5-n-heptyl-2-(4-cyanophenyl)pyrimidine, 2-(4-cyanophenyl)-5-(4-n-butylphenyl)pyrimidine and 4-ethyl-4'-n-butylbiphenyl and dihexyl ether.

Claim 25

A liquid crystal mixture, in accordance with claim 20, 10.3% p-n-butylbenzoic acid p'-cyanophenyl ester, 11.1% p-n-pentylbenzoic acid p'-cyanophenyl ester, 14.3% p-n-hexylbenzoic acid p'-cyanophenyl ester, 15.4% p-n-heptylbenzoic acid p'-cyanophenyl ester, 11.0% 5-n-pentyl-2-(4-cyanophenyl)pyrimidine, 21.2% 5-n-heptyl-2-(4-cyanophenyl)pyrimidine, 15.6% 2-(4-cyanophenyl)-5-(4-n-butylphenyl)pyrimidine and 15% 4-ethyl-4'-n-butylbiphenyl and 3% dihexyl ether.

Claim 26

A liquid crystal mixture, in accordance with claim 20, p-n-butylbenzoic acid p'-cyanophenyl ester, p-n-pentylbenzoic acid p'-cyanophenyl ester, p-n-hexylbenzoic acid p'-cyanophenyl ester, p-n-heptylbenzoic acid p'-cyanophenyl ester, 5-n-pentyl-2-(4-cyanophenyl)pyrimidine, 5-n-heptyl-2-(4-cyanophenyl)pyrimidine, 2-(4-cyanophenyl)-5-(4-n-butylphenyl)pyrimidine and 4-methyl-4'-n-pentylbiphenyl.

Claim 27

A liquid crystal mixture, in accordance with claim 20, 10.3% p-n-butylbenzoic acid p'-cyanophenyl ester, 11.1% p-n-pentylbenzoic acid p'-cyanophenyl ester, 14.3% p-n-hexylbenzoic acid p'-cyanophenyl ester, 15.4% p-n-heptylbenzoic acid p'-cyanophenyl ester, 11.0% 5-n-pentyl-2-(4-cyanophenyl)pyrimidine, 21.2% 5-n-heptyl-2-(4-cyanophenyl)pyrimidine, 15.6% 2-(4-cyanophenyl)-5-(4-n-butylphenyl)pyrimidine and 15% 4-methyl-4'-n-pentylbiphenyl.

Claim 28

A liquid crystal mixture, in accordance with claim 20, p-n-butylbenzoic acid p'-cyanophenyl ester, p-n-pentylbenzoic acid p'-cyanophenyl ester, p-n-hexylbenzoic acid p'-cyanophenyl ester, p-n-heptylbenzoic acid p'-cyanophenyl ester, 5-n-pentyl-2-(4-cyanophenyl)pyrimidine, 5-n-hexyl-2-(4-cyanophenyl)pyrimidine, 2-(4-cyanophenyl)-5-(4-n-butylphenyl)pyrimidine and 4-ethyl-4'-n-pentylbiphenyl.

Claim 29

A liquid crystal mixture, in accordance with claim 20, 10.3% p-n-butylbenzoic acid p'-cyanophenyl ester, 11.1% p-n-pentylbenzoic acid p'-cyanophenyl ester, 14.3% p-n-hexylbenzoic acid p'-cyanophenyl ester, 15.4% p-n-heptylbenzoic acid p'-cyanophenyl ester, 11.0% 5-n-pentyl-2-(4-cyanophenyl)pyrimidine, 21.2% 5-n-hexyl-2-(4-cyanophenyl)pyrimidine, 15.6% 2-(4-cyanophenyl)-5-(4-n-butylphenyl)pyrimidine and 15% 4-ethyl-4'-n-pentylbiphenyl.