Process for controlling cone tilt angle in mixtures of smectic liquid crystal compounds

• US 5,658,491 A
• Filed: 10/12/1995
• Issued: 08/19/1997
• Est. Priority Date: 10/12/1995
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Company
• Inventors: Radcliffe, Marc D., Savu, Patricia M., Snustad, Daniel C., Kistner, John F.
• Primary Examiner(s): KELLY, CYNTHIA HARRIS
• Application Number:
  US08/542,179
• Time in Patent Office: 677 Days
• Field of Search: 252/299.01, 252/299.6, 252/299.61, 252/299.66, 252/299.62, 252/299.63, 252/299.65, 252/299.67
• US Class Current: 252/299.01
• CPC Class Codes: C07D 239/26 with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, directly attached to ring carbon atoms
• CPC Class Codes: C09K 19/04 characterised by the chemical structure of the liquid crystal components , e.g. by a specific unit
• CPC Class Codes: C09K 19/3458 Uncondensed pyrimidines
• CPC Class Codes: C09K 19/3469 Pyrimidine with a specific end-group other than alkyl, alkoxy or -C*-

Abstract

A process for controlling the cone tilt angle of a tilted smectic liquid crystal composition comprises the step of combining (a) at least one liquid crystal composition comprising at least one smectic or latent smectic liquid crystal compound comprising (i) an aliphatic fluorocarbon terminal portion comprising a terminal fluoroalkyl or fluoroether group and an alkylene group having at least two carbon atoms and containing at least one catenary ether oxygen atom, (ii) an aliphatic hydrocarbon terminal portion, and (iii) a central core connecting the terminal portions; and (b) at least one liquid crystal composition comprising at least one smectic or latent smectic liquid crystal compound; with the provisos that at least one of the compositions (a) and (b) comprises at least one chiral liquid crystal compound and that the combining of compositions (a) and (b) provides an optically active, tilted chiral smectic liquid crystal composition. The process enables control of cone tilt angle and thereby control of the brightness characteristics of liquid crystal display devices.

Claims

1. A process for controlling the cone tilt angle of a tilted smectic liquid crystal composition comprising the step of combining (a) at least one liquid crystal composition comprising at least one smectic or latent smectic liquid crystal compound comprising (i) an aliphatic fluorocarbon terminal portion comprising a terminal fluoroalkyl or fluoroether group and an alkylene group having at least two carbon atoms and containing at least one catenary ether oxygen atom, (ii) an aliphatic hydrocarbon terminal portion, and (iii) a central core connecting said terminal portions;

and (b) at least one liquid crystal composition comprising at least one smectic or latent smectic liquid crystal compound;

with the provisos that at least one of said compositions (a) and (b) comprises at least one chiral liquid crystal compound and that said combining of compositions (a) and (b) provides an optically active, tilted chiral smectic liquid crystal composition.

2. The process of claim 1 wherein said composition (a) is utilized in an amount such that the resulting combination has a cone tilt angle between about 10 and about 35 degrees.

3. The process of claim 1 wherein said aliphatic fluorocarbon terminal portion is represented by the formula --D--R_h --R_f, where R_h is an alkylene group having at least two carbon atoms and containing at least one catenary ether oxygen atom;

R_f is fluoroalkyl or fluoroether; and

D is non-directionally selected from the group consisting of a covalent bond, --C(═

O)O--C_r H_2r, --O--C_r H_2r --, --O.paren open-st.C_s H_2s O.paren close-st._t C_r, H_2r, --, --C_r H_2r --, .paren open-st.C_s H_2s O.paren close-st._t C_r,H_2r,--, --OSO₂ --, --SO₂ --, --SO₂ --C_r H_2r --, ##STR51## --C.tbd.C--, --CH═

CH--, --C(═

O)--, --O(O═

)C--C_r H_2r --, ##STR52## --CH═

N--, --O--, --S--, --N(C_p H_2p+1)--, and combinations thereof, where r and r'"'"' are independently integers of 0 to 20, s is independently an integer of 1 to 10 for each (C_s H_2s O), t is an integer of 1 to 6, and p is an integer of 0 to 4.

4. The process of claim 3 wherein said R_f is perfluoroalkyl or perfluoroether and contains from 1 to 20 carbon atoms;

said R_h contains from 2 to 12 carbon atoms; and

said D is selected from the group consisting of --O--, --C(═

O)--, a covalent bond, and combinations thereof.

5. The process of claim 4 wherein said R_h contains from 2 to 8 carbon atoms and said D is --O--.

6. The process of claim 1 wherein said smectic or latent smectic liquid crystal compound of said composition (a) is represented by the general formula I:

##STR53## where M, N, and P are each independently selected from the group consisting of ##STR54## a, b, and c are each independently zero or an integer of from 1 to 3, with the proviso that the sum of a+b+c be at least 1;

each A and B are non-directionally and independently selected from the group consisting of a covalent bond, --C(═

O)--O--, --C(═

O)--S--, --C(═

O)--Se--, --C(═

O)--Te--, --(CH₂ CH₂)_k -- where k is 1 to 4, --CH═

CH--, --C.tbd.C--, --CH═

N--, --CH₂ --O--, --C(═

O)--, and --O--;

each X, Y, and Z are independently selected from the group consisting of --H, --Cl, --F, --Br, --I, --OH, --OCH₃, --CH₃, --CF₃, --OCF₃, --CN, and --NO₂ ;

each l, m, and n are independently zero or an integer of 1 to 4;

D is non-directionally selected from the group consisting of a covalent bond, --C(═

O)--O--C_r H_2r --, --O--C_r H_2r --, --O--(O═

)C--C_r H_2r --, --C.tbd.C--, --CH═

CH--, --C(═

O)--, --O.paren open-st.C_s H_2s O.paren close-st._t C_r,H_2r, --, --C_r H_2r --, .paren open-st.C_s H_2s O.paren close-st._t C_r, H_2r --, --O--, --S--, --OSO₂ --, --SO₂ --, --SO₂ --C_r H_2r --, ##STR55## --N(C_p H_2p+1)--, ##STR56## --CH═

N--, and combinations thereof, where r and r'"'"' are independently integers of 0 to 20, s is independently an integer of 1 to 10 for each (C_s H_2s O), t is an integer of 1 to 6, and p is an integer of 0 to 4;

R is selected from the group consisting of --O--((C_q'"'"' H_{2q'"'"'--v'"'"'} --(R'"'"')_v'"'"')--O)_w --C_q H_2q+1--v --(R'"'"')_v, --((C_q'"'"' H_{2q'"'"'--v'"'"'} --(R'"'"')_v'"'"')--O)_w --C_q H_2q+1--v --(R'"'"')_v, --C(═

O)--O--C_q H_2q+1--v --(R'"'"')_v, --O--(O═

)C--C_q H_2q+1--v --(R'"'"')_v, ##STR57## --CR'"'"'H--(D)_g --CR'"'"'H--C_q H_2q+1--v --(R'"'"')_v, where each R'"'"' is independently selected from the group consisting of --Cl, --F, --CF₃, --NO₂, --CN, --H, --C_q H_2q+1, --O--(O═

)C--C_q H_2q+1, --C(═

O)--O--C_q H_2q+1, --Br, --OH, and --OC_q H_2q+1 ;

q'"'"' is independently an integer of 1 to 20 for each (C_q'"'"'l H_2q'"'"' --O);

q is an integer of 1 to 20;

w is an integer of 0 to 10;

v is an integer of 0 to 6;

each v'"'"' is independently an integer of 0 to 6;

g is an integer of 1 to 3;

each D is independently and non-directionally selected from the group set forth for D above, with the proviso that the ring containing D has from 3 to 10 ring atoms;

each W is independently selected from the group consisting of N, CR'"'"', and SIR'"'"';

R_h is an alkylene group having at least two carbon atoms and containing at least one catenary ether oxygen atom; and

R_f is fluoroalkyl or fluoroether.

7. The process of claim 6 wherein said R_f is perfluoroalkyl or perfluoroether and contains from 1 to 20 carbon atoms;

said R_h contains from 2 to 12 carbon atoms; and

said D is selected from the group consisting of --O--, --C(═

O)--, a covalent bond, and combinations thereof.

8. The process of claim 7 wherein said R_h contains from 2 to 8 carbon atoms and said D is --O--.

9. The process of claim 6 wherein said R_h is represented by the general formula (C_s H_2s O)_t C_r'"'"' H_2r'"'"' --, wherein s is independently an integer of 1 to 10 for each (C_s H_2s O), t is an integer of 1 to 6, and r'"'"' is an integer of 1 to 10.

10. The process of claim 9 wherein said s is an integer of 2 to 7, said t is an integer of 1 to 3, and said r'"'"' is an integer of 1.

11. The process of claim 6 wherein said R_f is represented by the formula --C_q F_2q X'"'"', where q is as defined in claim 6 and X'"'"' is hydrogen or fluorine.

12. The process of claim 6 wherein said R_f is represented by the formula --R_f'"'"' --R_h'"'"', where R_f'"'"' is a linear or branched, perfluorinated or partially-fluorinated alkylene group having from 1 to 10 carbon atoms and optionally containing one or more catenary ether oxygen atoms, and R_h, is a linear or branched alkyl group having from 1 to 14 carbon atoms and optionally containing one or more catenary ether oxygen atoms.

13. The process of claim 6 wherein said R_f is represented by the formula --(C_x F_2x O)_z C_y F_2y+1, where x is independently an integer of 1 to 10 for each (C_x F_2x O), y is an integer of 1 to 10, and z is an integer of 1 to 10.

14. The process of claim 1 wherein said smectic or latent smectic liquid crystal compound of said composition (b) has at least one fluorinated terminal portion.

15. The process of claim 14 wherein said fluorinated terminal portion comprises at least one perfluoroether group.

16. Fluorine-containing liquid crystal compounds represented by the general formula I:

##STR58## where M, N, P, A, B, X, Y, Z, a, b, c, l, m, n, D, and R are as defined in claim 6;

R_h is represented by the directional general formula .paren open-st.C₃ H_2s O.paren close-st._t C_r, H_2r,═

, wherein s is independently an integer of 3 to 10 for each (C_s H_2s O), t is an integer of 1 to 6, and r'"'"' is an integer of 1 to 10; and

R_f is fluoroether;

with the proviso that the compounds do not exhibit at least one tilted smectic mesophase.

17. The compounds of claim 16 wherein said s is an integer of 3 to 7, said t is an integer of 1 to 3, and said r'"'"' is an integer of 1 to 5.

18. The compounds of claim 17 wherein said t is an integer of 1 to 2 and said r'"'"' is an integer of 1.

19. The compounds of claim 16 wherein said R_h has from 4 to 12 carbon atoms.

20. The compounds of claim 16 wherein said R_f is perfluoroether.

21. The compounds of claim 20 wherein said R_f is represented by the formula --(C_x F_2x O)_z C_y F_2y+1, where x is independently an integer of 1 to 10 for each (C_x F_2x O), y is an integer of 1 to 10, and z is an integer of 1 to 10.

22. A mixture of liquid crystal compounds prepared by the process of claim 1, wherein said alkylene group has at least 4 carbon atoms.

23. A mixture of liquid crystal compounds prepared by the process of claim 21 and having a cone tilt angle between about 10 and about 35 degrees.

24. A mixture of liquid crystal compounds comprising at least one compound of claim 16.

25. A liquid crystal display device containing the mixture of claim 22.

26. A liquid crystal display device containing the mixture of claim 23.

27. A liquid crystal display device containing the mixture of claim 24.

28. A process for controlling the cone tilt angle of a tilted smectic liquid crystal composition comprising the step of combining (a) at least one liquid crystal composition comprising at least one smectic or latent smectic liquid crystal compound comprising (i) an aliphatic fluorocarbon terminal portion represented by the formula --D--R_h --R_f, where R_h contains from 2 to 12 carbon atoms and is represented by the general formula (C_s H_2s O)_t C_r'"'"' H_2r'"'"' --, wherein s is independently an integer of 1 to 10 for each (C_s H_2s O), t is an integer of 1 to 6, and r'"'"' is an integer of 1 to 10;

R_f is perfluoroalkyl or perfluoroether and contains from 1 to 20 carbon atoms; and

D is selected from the group consisting of --O--, --C(═

O)--, a covalent bond, and combinations thereof;

(ii) an aliphatic hydrocarbon terminal portion; and

(iii) a central core connecting said terminal portions; and

(b) at least one liquid crystal composition comprising at least one fluorine-containing, smectic or latent smectic liquid crystal compound;

with the provisos that at least one of said compositions (a) and (b) comprises at least one chiral liquid crystal compound and that said combining of compositions (a) and (b) provides an optically active, tilted chiral smectic liquid crystal composition.

29. Fluorine-containing liquid crystal compounds represented by the general formula I:

##STR59## where M is pyrimidine;

N is phenyl;

A is a covalent bond;

X and Y hydrogen;

a and b are integers of 1;

l is an integer of 2;

m is an integer of 4;

D is --O--;

R is an alkyl, fluoroalkyl, alkoxy, or fluoroalkoxy group having from 4 to 8 carbon atoms and optionally containing one or more catenary ether oxygen atoms;

R_h has from about 4 to about 8 carbon atoms and is represented by the directional general formula .paren open-st.C_s H_2s O.paren close-st._t C_r,H_2r'"'"' --, wherein s is independently an integer of 3 to 7 for each (C_s H_2s O), t is an integer of 1 to 2, and r'"'"' is an integer of 1; and

R_f is a perfluoroether group represented by the formula --(C_x F_2x O)_z C_y F_2y+1, where x is independently an integer of 1 to 10 for each (C_x F_2x O), y is an integer of 1 to 10, and z is an integer of 1 to 10;

with the proviso that the compounds do not exhibit at least one tilted smectic mesophase.