Liquid crystal composition

Abstract

Disclosed is a liquid crystal composition comprising one or more compounds represented by formula I, one or more compounds represented by formula II, and one or more compounds represented by formula III: ##STR00001##
The liquid crystal composition has simultaneously a lower rotary viscosity, a better photoelectric performance, a higher clearing point, a good low temperature performance, and less display defects. Further disclosed is a liquid crystal display element or device comprising the liquid crystal composition.

Claims

1. A liquid crystal composition, characterized by comprising one or more compounds represented by formula I, one or more compounds represented by formula II, and one or more compounds represented by formula III: ##STR00035## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 each independently represent an alkyl group having a carbon atom number of 1-10, a fluorine-substituted alkyl group having a carbon atom number of 1-10, an alkoxy group having a carbon atom number of 1-10, a fluorine-substituted alkoxy group having a carbon atom number of 1-10, an alkenyl group having a carbon atom number of 2-10, a fluorine-substituted alkenyl group having a carbon atom number of 2-10, an alkenoxy group having a carbon atom number of 3-8 or a fluorine-substituted alkenoxy group having a carbon atom number of 3-8, and any one or more H in a CH.sub.2 in the groups represented by R.sub.3 , R.sub.4 and R.sub.5 may be substituted with cyclopentyl, cyclobutyl, or cyclopropyl, wherein when more than one CH.sub.2 in the groups represented by R.sub.3, R.sub.4 and R.sub.5 comprise an H substituted with cyclopentyl, cyclobutyl, or cyclopropyl, such substituted CH.sub.2 groups are non-consecutive; Z.sub.1 and Z.sub.2 each independently represent a single bond, —CH.sub.2CH.sub.2— or —CH.sub.2O—; Z.sub.3 represents one of a single bond, —CH.sub.2CH.sub.2—, —CH.sub.2O—, —CH.sub.2—, and —COO—; M represents one of cyclopentyl, cyclopropyl, cyclobutyl and cycloheptyl; ##STR00036## represents 1,4-phenylene or 1,4-cyclohexylene; ##STR00037## represents 1,4-phenylene or 1,4-cyclohexylene; ##STR00038## represents one of 1,4-phenylene, 1,4-cyclohexylene, a fluorine-substituted 1,4-phenylene and 1,4-cyclohexenylene; ##STR00039## represents one of 1,4-phenylene, 1,4-cyclohexylene, a fluorine-substituted 1,4-phenylene and 1,4-cyclohexenylene; and m and n each independently represent 0, 1 or 2, characterized in that said liquid crystal composition is a negative liquid crystal composition, and further comprises one or more compounds represented by formula IV: ##STR00040## wherein R.sub.6 and R.sub.7 each independently represent an alkyl group having a carbon atom number of 1-10, a fluorine-substituted alkyl group having a carbon atom number of 1-10, an alkoxy group having a carbon atom number of 1-10, a fluorine-substituted alkoxy group having a carbon atom number of 1-10, an alkenyl group having a carbon atom number of 2-10, a fluorine-substituted alkenyl group having a carbon atom number of 2-10, an alkenoxy group having a carbon atom number of 3-8 or a fluorine-substituted alkenoxy group having a carbon atom number of 3-8, and any one or more H in a CH.sub.2 in the groups represented by R.sub.6 and R.sub.7 may be substituted with cyclopentyl, cyclobutyl, cyclopropyl, wherein when more than one CH.sub.2 in the groups represented by R.sub.6 and R.sub.7 comprise an H substituted with cyclopentyl, cyclobutyl, or cyclopropyl, such substituted CH.sub.2 groups are non-consecutive; and W represents O,S or —CH.sub.2O—.

2. The liquid crystal composition according to claim 1, characterized in that said one or more compounds represented by formula I are one or more selected from compounds represented by formulae I-1 to I-17 below, said one or more compounds represented by formula II are one or more selected from compounds represented by formulae II-1 to II-13 below, and said one or more compounds represented by formula III are one or more selected from compounds represented by formulae III-1 to III-8 below: ##STR00041## ##STR00042## ##STR00043## wherein R.sub.3 and R.sub.4 each independently represent an alkyl group having a carbon atom number of 1-10, a fluorine-substituted alkyl group having a carbon atom number of 1-10, an alkoxy group having a carbon atom number of 1-10, a fluorine-substituted alkoxy group having a carbon atom number of 1-10, an alkenyl group having a carbon atom number of 2-10, a fluorine-substituted alkenyl group having a carbon atom number of 2-10, an alkenoxy group having a carbon atom number of 3-8 or a fluorine-substituted alkenoxy group having a carbon atom number of 3-8, and any one or more H in a CH.sub.2 in the groups represented by R.sub.3 and R.sub.4 may be substituted with cyclopentyl, cyclobutyl, or cyclopropyl, wherein when more than one CH.sub.2 in the groups represented by R.sub.3 and R.sub.4 comprise an H substituted with cyclopentyl, cyclobutyl or cyclopropyl, such substituted CH.sub.2 groups are non-consecutive; and R.sub.51 represents an alkyl group having a carbon atom number of 1-10.

3. The liquid crystal composition according to claim 1, characterized in that in said liquid crystal composition, the total mass content of the compounds represented by formula I is 10-70%, the total mass content of the compounds represented by formula II is 10-70%, and the total mass content of the compounds represented by formula III is 1-20%.

4. The liquid crystal composition according to claim 1, characterized in that said liquid crystal composition is a negative liquid crystal composition, and further comprises one or more compounds represented by formula V: ##STR00044## wherein R.sub.8 and R.sub.9 each independently represent an alkyl group having a carbon atom number of 1-10, a fluorine-substituted alkyl group having a carbon atom number of 1-10, an alkoxy group having a carbon atom number of 1-10, a fluorine-substituted alkoxy group having a carbon atom number of 1-10, an alkenyl group having a carbon atom number of 2-10, a fluorine-substituted alkenyl group having a carbon atom number of 2-10, an alkenoxy group having a carbon atom number of 3-8 or a fluorine-substituted alkenoxy group having a carbon atom number of 3-8, and any one or more H in a CH.sub.2 in the groups represented by R.sub.8 and R.sub.9 may be substituted with cyclopropyl, wherein when more than one CH.sub.2 in the groups represented by R.sub.8 and R.sub.9 comprise an H substituted with cyclopropyl, such substituted CH.sub.2 groups are non-consecutive; and ##STR00045## each independently represent 1,4-phenylene, a fluorine-substituted 1,4-phenylene, 1,4-cyclohexylene or 1,4-cyclohexenylene.

5. A liquid crystal composition, characterized by comprising one or more compounds represented by formula I, one or more compounds represented by formula II, and one or more compounds represented by formula III: ##STR00046## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 each independently represent an alkyl group having a carbon atom number of 1-10, a fluorine-substituted alkyl group having a carbon atom number of 1-10, an alkoxy group having a carbon atom number of 1-10, a fluorine-substituted alkoxy group having a carbon atom number of 1-10, an alkenyl group having a carbon atom number of 2-10, a fluorine-substituted alkenyl group having a carbon atom number of 2-10, an alkenoxy group having a carbon atom number of 3-8 or a fluorine-substituted alkenoxy group having a carbon atom number of 3-8, and any one or more H in a CH.sub.2 in the groups represented by R.sub.3, R.sub.4 and R.sub.5 may be substituted with cyclopentyl, cyclobutyl, or cyclopropyl, wherein when more than one CH.sub.2 in the groups represented by R.sub.3, R.sub.4 and R.sub.5 comprise an H substituted with cyclopentyl, cyclobutyl, or cyclopropyl, such substituted CH.sub.2 groups are non-consecutive; Z.sub.1 and Z.sub.2 each independently represent a single bond, —CH.sub.2CH.sub.2— or —CH.sub.2O—; Z.sub.3 represents one of a single bond, —CH.sub.2CH.sub.2—, -CH.sub.2O—, —CH.sub.2—, and —COO—; M represents one of cyclopentyl, cyclopropyl, cyclobutyl and cycloheptyl; ##STR00047## represents 1,4-phenylene or 1,4-cyclohexylene; ##STR00048## represents 1,4-phenylene or 1,4-cyclohexylene; ##STR00049## represents one of 1,4-phenylene, 1,4-cyclohexylene, a fluorine-substituted 1,4-phenylene and 1,4-cyclohexenylene; ##STR00050## represents one of 1,4-phenylene, 1,4-cyclohexylene, a fluorine-substituted 1,4-phenylene and 1,4-cyclohexenylene; and m and n each independently represent 0, 1 or 2, characterized in that said liquid crystal composition is a negative liquid crystal composition, and further comprises one or more compounds represented by formula VI: ##STR00051## wherein R.sub.11 and R.sub.10 each independently represent an alkyl group having a carbon atom number of 1-10, a fluorine-substituted alkyl group having a carbon atom number of 1-10, an alkoxy group having a carbon atom number of 1-10, a fluorine-substituted alkoxy group having a carbon atom number of 1-10, an alkenyl group having a carbon atom number of 2-10, a fluorine-substituted alkenyl group having a carbon atom number of 2-10, an alkenoxy group having a carbon atom number of 3-8 or an fluorine-substituted alkenoxy group having a carbon atom number of 3-8; and ##STR00052## represents 1,4-phenylene, 1,4-cyclohexylene or 1,4-cyclohexenylene.

6. The liquid crystal composition according to claim 1, characterized in that the compound represented by formula IV is one selected from formulae IV-1 to IV-9 below: ##STR00053## wherein R.sub.61 and R.sub.71 each independently represent an alkyl group having a carbon atom number of 1-10.

7. The liquid crystal composition according to claim 4, characterized in that the compound represented by formula V is one selected from formulae V-1 to V-7 below: ##STR00054## wherein R.sub.81 represents an alkyl group having a carbon atom number of 1-6; R.sub.82 represents an alkoxy group having a carbon atom number of 1-6; R.sub.91 represents an alkyl group having a carbon atom number of 2-6; and R.sub.92 represents an alkenyl group having a carbon atom number of 2-6.

8. The liquid crystal composition according to claim 5, characterized in that the compound represented by formula VI is one selected from formulae VI-1 to VI-4 below: ##STR00055## wherein R.sub.101 and R.sub.111 each independently represent an alkyl group having a carbon atom number of 1-6.

9. A liquid crystal display element or device comprising the liquid crystal composition of claim 1.

10. A liquid crystal display element or device comprising the liquid crystal composition of claim 2.

11. A liquid crystal display element or device comprising the liquid crystal composition of claim 3.

12. A liquid crystal display element or device comprising the liquid crystal composition of claim 4.

13. A liquid crystal display element or device comprising the liquid crystal composition of claim 5.

14. A liquid crystal display element or device comprising the liquid crystal composition of claim 6.

15. A liquid crystal display element or device comprising the liquid crystal composition of claim 7.

16. A liquid crystal display element or device comprising the liquid crystal composition of claim 8.

Description

DETAILED DESCRIPTION OF EMBODIMENTS

(1) In order to more clearly illustrate the present invention, the present invention will be further described below in conjunction with preferred embodiments. A person skilled in the art should understand that the following contents described in detail are illustrative rather than limiting, and should not limit the scope of protection of the present invention.

(2) In this description, unless otherwise specified, percentages are mass percentages, temperatures are in degree Celsius (° C.), and the specific meanings of the other symbols and the test conditions are as follows:

(3) Cp represents the clearing point (° C.) of the liquid crystal measured by a DSC quantitative method;

(4) S—N represents the melting point (° C.) for the transformation of a liquid crystal from a crystal state to a nematic phase;

(5) Δn represents the optical anisotropy, n.sub.o is the refractive index of an ordinary light, n.sub.e is the refractive index of an extraordinary light, with the test conditions being 25±2° C. and 589 nm, and an abbe refractometer for testing;

(6) Δε represents the dielectric anisotropy, Δε=ε.sub.//−ε.sub.⊥, wherein ε.sub.// is a dielectric constant parallel to a molecular axis, and ε.sub.⊥ is a dielectric constant perpendicular to the molecular axis, the test condition is 25±0.5° C., a 20 micron parallel cell is used, and INSTEC: ALCT-IR1 is used for the test;

(7) γ1 represents a rotary viscosity (mPa.Math.s), with the test condition being 25±0.5° C., a 20 micron parallel cell, and INSTEC: ALCT-IR1 for testing; and

(8) ρ represents an electrical resistivity (S-cm), with the test conditions being: 25±2° C., and the test instruments being a TOYO SR6517 high resistance instrument and an LE-21 liquid electrode.

(9) VHR represents a voltage holding rate (%), with the test condition being 20±2° C., a voltage of ±5 V, a pulse width of 10 ms, and a voltage holding time of 16.7 ms. The test equipment is a TOYO Model 6254 liquid crystal performance comprehensive tester.

(10) τ represents a response time (ms), with the test instrument being DMS-501 and the test conditions being: 25±0.5° C., a test cell that is a 3.3 micron IPS test cell, an electrode spacing and an electrode width, both of which are 10 microns, and an included angle between the frictional direction and the electrode of 10°.

(11) In the embodiments of the present invention, liquid crystal monomer structures are represented by codes, wherein the codes of ring structures, end groups and linking groups of liquid crystals are represented, as shown in tables 1 and 2 below.

(12) TABLE-US-00001 TABLE 1 Corresponding code for ring structure Ring structure Corresponding code 0 C P G Gi Y Sa Sb Sc W

(13) TABLE-US-00002 TABLE 2 Corresponding code for end group and linking group End group and linking group Corresponding code C.sub.nH.sub.2n+1— n- C.sub.nH.sub.2n+1O— nO— —OCF.sub.3 —OT —CF.sub.2O— -Q- —CH.sub.2O— —O— —F —F —CN —CN —CH.sub.2CH.sub.2— -E- —CH═CH— —V— —COO— —COO— —CH═CH—C.sub.nH.sub.2n+1 Vn- C(5)- 0 C(3)- C(3)1-

EXAMPLES

(14) ##STR00032##

(15) In the embodiments of the present invention, the method for preparing the liquid crystal composition comprises: weighing various monomers at a designed ratio into a beaker, heating these monomers to a clearing point with stirring, holding the mixture for 30 minutes, cooling the mixture to room temperature, and testing various parameters under test conditions.

(16) The following specific examples are used to illustrate the present invention.

Example 1

(17) The formula of the liquid crystal composition and the corresponding properties thereof are as shown in table 3 below.

(18) TABLE-US-00003 TABLE 3 Formula of the liquid crystal composition of Example 1 and the corresponding properties thereof Category Liquid crystal monomer code Content (%) II 5-CY-O4 11 II 5-PY-O2 9 II 5-COY-O2 12 II 3-CCOY-O2 3 II 5-CCY-O2 10 II 3-CPY-O2 10 I 3-CC-2 10 I 3-CC-V 20 I 1-PP-2V 5 III C(5)O-W-O4 10 Cp: 55 γ.sub.1: 80 Δn: 0.0948 Δε: −4.6

Comparative Example 1

(19) The 10% of the compound of formula Ill, i.e., C(5)O—W—O4, in Example 1 is replaced by

(20) ##STR00033##
which is an existing similar compound, to give a mixture of Comparative Example 1 with a clearing point CP reduced to 53° C. and a Δε increased to −4.4.

Comparative Example 2

(21) The 10% of the compound of formula III, i.e., C(5)O—W—O4, in Example 1 is replaced by

(22) ##STR00034##
which is an existing similar compound, to give a mixture of Comparative Example 1 with a clearing point CP reduced to 50° C. and a Δε increased to −4.2.

Example 2

(23) The formula of the liquid crystal composition and the corresponding properties thereof are as shown in table 4 below.

(24) TABLE-US-00004 TABLE 4 Formula of the liquid crystal composition of Example 1 and the corresponding properties thereof Category Liquid crystal monomer code Content (%) II 5-CY-O4 11 II 5-CLY-O2 9 II 3-COY-O2 12 II 3-CCOY-O2 12 II 5-CCY-O2 16 II 3-CPY-O2 10 I 3-CC-2 10 I 3-CC-V 5 I 1-PP-2V 5 IV C(5)O-Sc-O4 4 III C(5)O-W-O4 6 Cp: 81 γ.sub.1: 155 Δn: 0.106 Δε: −5.8

Example 3

(25) The formula of the liquid crystal composition and the corresponding properties thereof are as shown in table 5 below.

(26) TABLE-US-00005 TABLE 5 Formula of the liquid crystal composition of Example 1 and the corresponding properties thereof Category Liquid crystal monomer code Content (%) II 5-CY-O4 3 II 5-CLY-O2 2 II 3-COY-O2 2 II 3-CCOY-O2 3 II 5-CCY-O2 5 II 3-CPY-O2 5 I 3-CC-2 10 I 3-CC-V 30 I 1-PP-5 10 IV C(5)O-Sb-O4 5 V 3-CPP-2V1 5 V 3-CCP-1 5 III C(5)O-W-O4 15 Cp: 60 γ.sub.1: 75 Δn: 0.101 Δε: −3.4

Example 4

(27) The formula of the liquid crystal composition and the corresponding properties thereof are as shown in table 6 below.

(28) TABLE-US-00006 TABLE 6 Formula of the liquid crystal composition of Example 1 and the corresponding properties thereof Category Liquid crystal monomer code Content (%) II 5-CY-O4 6 II 5-PY-O2 9 II 3-COY-O2 2 II 3-CCOY-O2 3 II 5-CCY-O2 10 II 3-CPY-O2 10 I 3-CC-2 10 I 3-CC-V 25 I O2-PP-5 5 IV C(5)O-Sa-O4 5 V 3-CPP-2 8 V 3-CCP-O1 5 III C(5)O-W-O4 2 Cp: 75 γ.sub.1: 90 Δn: 0.104 Δε: −3.1

Example 5

(29) The formula of the liquid crystal composition and the corresponding properties thereof are as shown in table 7 below.

(30) TABLE-US-00007 TABLE 7 Formula of the liquid crystal composition of Example 1 and the corresponding properties thereof Category Liquid crystal monomer code Content (%) II 5-CY-O4 5 II 5-PY-O2 5 II 3-COY-O2 5 II 3-CCOY-O2 5 II 5-CCY-O2 10 II 3-CPY-O2 10 I 3-CP-O2 10 I 3-CC-V 25 I 1-PP-2V 5 IV C(5)O-Sb-O4 5 V 1V-CPP-2 5 V 3-CCP-O1 5 III C(5)O-W-O4 5 Cp: 75 γ.sub.1: 98 Δn: 0.106 Δε: −3.6

Example 6

(31) The formula of the liquid crystal composition and the corresponding properties thereof are as shown in table 8 below.

(32) TABLE-US-00008 TABLE 8 Formula of the liquid crystal composition of Example 1 and the corresponding properties thereof Category Liquid crystal monomer code Content (%) II 5-CY-O4 10 II 5-PY-O2 5 II 3-COY-O2 2 II 3-CCOY-O2 3 II 5-CCY-O2 10 II 3-CPY-O2 10 I 3-CC-V1 10 I 3-CC-V 20 I 1-PP-5 6 IV C(5)O-Sb-O4 4 V 1V-CPP-2 5 V C(3)1-PGP-2 5 III C(5)O-W-O4 10 Cp: 71 γ.sub.1: 105 Δn: 0.116 Δε: −3.8

Example 7

(33) The formula of the liquid crystal composition and the corresponding properties thereof are as shown in table 9 below.

(34) TABLE-US-00009 TABLE 9 Formula of the liquid crystal composition of Example 1 and the corresponding properties thereof Category Liquid crystal monomer code Content (%) II 5-CY-O4 5 II 5-CLY-O2 5 II 3-COY-O2 12 II 3-CCOY-O2 3 II 5-CCY-O2 10 II 5-PPY-O2 10 I 3-CP-O2 5 I 3-CC-5 20 I 1-PP-2V 5 IV C(5)O-Sa-O4 5 V 3-CPP-2V1 5 V C(3)1-PGP-2 5 III C(3)O-W-O4 8 VI 2-CPPC-3 2 Cp: 88 γ.sub.1: 130 Δn: 0.125 Δε: −4.3

Example 8

(35) The formula of the liquid crystal composition and the corresponding properties thereof are as shown in table 10 below.

(36) TABLE-US-00010 TABLE 10 Formula of the liquid crystal composition of Example 1 and the corresponding properties thereof Category Liquid crystal monomer code Content (%) II 5-CY-O4 10 II 5-PY-O2 5 II 3-COY-O2 2 II 3-CCOY-O2 3 II 5-CCY-O2 10 II 3-CPY-O2 10 I 3-CC-V1 10 I 3-CC-V 20 I 1-PP-5 6 IV C(5)O-Sb-O4 4 V 1V-CPP-2 5 V C(3)1-PYP-2 5 III C(5)O-W-O4 10 Cp: 70 γ.sub.1: −110 Δn: 0.115 Δε: −4.0

(37) As can be seen from the above examples, the liquid crystal mixture of the present invention has a larger dielectric anisotropy, a higher clearing point, a moderate refractive index, and a lower rotary viscosity, and is very suitable for liquid crystal display devices in IPS and VA modes.

(38) Obviously, the above-mentioned examples of the present invention are merely examples for clearly illustrating the present invention, rather than limiting the embodiments of the present invention; for a person of ordinary skill in the art, on the basis of the above description, other variations or changes in different forms may also be made, all the embodiments cannot be provided exhaustively herein, and any obvious variation or change derived from the technical solution of the present invention is still within the scope of protection of the present invention.