Liquid crystal composition and liquid crystal display device

Abstract

Disclosed are a liquid crystal composition and a liquid crystal display device. The liquid crystal composition comprises at least one compound of general formula I, at least one compound of general formula II, at least one compound of general formula III, and at least one compound of general formula IV. By compounding the four compounds, the composition can have advantages of a wide temperature range of nematic phase, a low viscosity and a low threshold voltage, and the liquid crystal display element can have a short response time and great power saving performance.

Claims

1. A liquid crystal composition, comprising at least two compounds of general formula I, at least one compound of general formula II, at least one compound of general formula III, and at least one compound of general formula IV: ##STR00036## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6 and R.sub.7 each independently represent a linear or branched alkyl or alkoxy containing 1 to 10 carbon atoms or a linear or branched alkenyl or alkenyloxy containing 2 to 12 carbon atoms; Z.sub.1 represents a linear or branched alkenyl containing 4 to 7 carbon atoms; Z.sub.2 represents —CH.sub.2—O—, —O—CH.sub.2—, —CO—O—, —O—CO—, —CH═CH— or —CH.sub.2—CH.sub.2—; Z.sub.3, Z.sub.4, and Z.sub.5 each independently represent a single bond, —COO—, —CH.sub.2—CH.sub.2—, —CH═CH— or —CH.sub.2—O—; n1 represents 1 or 2; the ring ##STR00037## the ring ##STR00038## and the ring ##STR00039## each independently represent ##STR00040## n2 represents 0, 1 or 2, and when n2 represents 2, ring ##STR00041## is the same or different; the ring ##STR00042## and the ring ##STR00043## each independently represent ##STR00044## n3 represents 0, 1 or 2, and when n3 represents 2, ring ##STR00045## is the same or different; wherein the dashed line represents an attachment position; wherein the compound of general formula III does not comprise the compound of general formula I, and the compound of general formula IV does not comprise the compound of general formula II.

2. The liquid crystal composition of claim 1, wherein the compound of general formula I accounts for 1% to 40% of the total weight of the liquid crystal composition.

3. The liquid crystal composition of claim 2, wherein the compound of general formula I accounts for preferably 5% to 35% of the total weight of the liquid crystal composition.

4. The liquid crystal composition of claim 3, wherein the compound of general formula I accounts for preferably 5% to 30% of the total weight of the liquid crystal composition.

5. The liquid crystal composition of claim 1, wherein the compound of general formula II accounts for 1% to 70% of the total weight of the liquid crystal composition.

6. The liquid crystal composition of claim 5, wherein the compound of general formula II accounts for preferably 5% to 65% of the total weight of the liquid crystal composition.

7. The liquid crystal composition of claim 6, wherein the compound of general formula II accounts for preferably 5% to 60% of the total weight of the liquid crystal composition.

8. The liquid crystal composition of claim 1, wherein the compound of general formula III accounts for 10% to 70% of the total weight of the liquid crystal composition.

9. The liquid crystal composition of claim 8, wherein the compound of general formula III accounts for preferably 15% to 65% of the total weight of the liquid crystal composition.

10. The liquid crystal composition of claim 9, wherein the compound of general formula III accounts for preferably 20% to 60% of the total weight of the liquid crystal composition.

11. The liquid crystal composition of claim 1, wherein the compound of general formula IV accounts for 1% to 50% of the total weight of the liquid crystal composition.

12. The liquid crystal composition of claim 11, wherein the compound of general formula IV accounts for preferably 1% to 40% of the total weight of the liquid crystal composition.

13. The liquid crystal composition of claim 12, wherein the compound of general formula IV accounts for preferably 1% to 35% of the total weight of the liquid crystal composition.

14. The liquid crystal composition of claim 1, wherein the compound of general formula I is a combination of at least two of compounds having the following structures: ##STR00046## wherein R.sub.1 represents a linear or branched alkyl or alkoxy containing 1 to 10 carbon atoms or a linear or branched alkenyl or alkenyloxy containing 2 to 12 carbon atoms.

15. The liquid crystal composition of claim 1, wherein the compound of general formula II is any one or a combination of at least two of compounds having the following structures: ##STR00047## wherein R.sub.2 and R.sub.3 each independently represent a linear or branched alkyl or alkoxy containing 1 to 10 carbon atoms or a linear or branched alkenyl or alkenyloxy containing 2 to 12 carbon atoms.

16. The liquid crystal composition of claim 1, wherein the compound of general formula III is any one or a combination of at least two of compounds having the following structures: ##STR00048## ##STR00049## ##STR00050## wherein R.sub.4 and R.sub.5 each independently represent a linear or branched alkyl or alkoxy containing 1 to 10 carbon atoms or a linear or branched alkenyl or alkenyloxy containing 2 to 12 carbon atoms.

17. The liquid crystal composition of claim 16, wherein the compound of general formula III is any one or a combination of at least two of compounds having structures of III-1, III-2, III-3, III-4, III-9, III-11, III-12, III-13, III-15, III-16, III-17, III-18, III-19, III-20, III-21, III-22 and III-23.

18. The liquid crystal composition of claim 16, wherein in the compound of general formula III-1, the compound of general formula III-2 and the compound of general formula III-3, at least one of R.sub.4 and R.sub.5 represents a halogenated or unhalogenated linear alkenyl or alkenyloxy having 2 to 10 carbon atoms.

19. The liquid crystal composition of claim 1, wherein the compound of general formula IV is any one or a combination of at least two of compounds having the following structures: ##STR00051## wherein R.sub.6 and R.sub.7 each independently represent a linear or branched alkyl or alkoxy containing 1 to 10 carbon atoms or a linear or branched alkenyl or alkenyloxy containing 2 to 12 carbon atoms.

20. A liquid crystal display device, comprising the liquid crystal composition of claim 1.

Description

DETAILED DESCRIPTION

(1) The technical solutions of the present disclosure are further described below through specific embodiments. Those skilled in the art should understand that the embodiments are merely used to help understand the present disclosure and should not be regarded as specific limitations to the present disclosure.

(2) For ease of expression, in the following examples, the group structures of the liquid crystal composition are represented by the codes listed in Table 1.

(3) TABLE-US-00001 TABLE 1 Group structure code for compound in the liquid crystal composition Group Unit Structure Code Group Name C 1,4-cyclohexylene C(N) 1-cyano-1,4-cyclohexylene 0 P 1,4-phenylene I indan-2,5-diyl G 2-fluoro-1,4-phenylene U 2,6-difluoro-1,4-phenylene W 2,3-difluoro-1,4-phenylene P(F, Cl) 2-chloro-3-fluoro-1,4- phenylene P(2N) 2,3-dicyano-1,4-phenylene W(1) 2,3-difluoro-6-methyl-1,4- phenylene Na(3F) 1,2,8-trifluoro-3,7- naphthylene A 2-oxohexacyclo 0 AI 3-oxohexacyclo D 1,3-dioxane-2,5-diyl Q or 1(2F)O difluoro ether group —O— O oxygen substituent group —F F fluorine substituent group —CH═CH— V alkenyl —C≡C— T alkynyl V(2F) diflurooalkenyl —COO— E ester bridge bond —C.sub.nH.sub.2n+1 or —C.sub.mH.sub.2m+1 n or m alkyl L 2-alkenyl-1,4- cyclohexylene

(4) The structure codes will be described with a compound having the following structural formula as an example:

(5) ##STR00035##
The structural formula can be expressed as nCCEPCm if it is represented by the codes shown in Table 1, wherein n represents the number of carbon atoms of the alkyl on the left end, for example, a case where n is 3 represents that the alkyl is —C.sub.3H.sub.7; C represents a cyclohexylene group; E represents an ester group; P represents a phenylene; and m represents the number of carbon atoms of the alkyl on the right end, for example, a case where m is 2 represents that the alkyl is —C.sub.2H.sub.5.

(6) In the following examples, abbreviated codes of the performance test items are shown in Table 2.

(7) TABLE-US-00002 TABLE 2 Abbreviated code for performance test item Test Item Code Meaning Δn optical anisotropy (589 nm, 25° C.) Δε dielectric anisotropy (1 KHz, 25° C.) Cp liquid crystal clearing point γ1 rotary viscosity (mPa .Math. s, 25° C.) Tc low-temperature storage phase change point (i.e., the lower-limit temperature of nematic phase, ° C.) V.sub.th threshold voltage (the characteristic voltage at a relative transmittance of 10%) η kinetic viscosity (cP, 25° C.)

(8) Wherein, the Cp (clearing point) was measured in a differential scanning calorimetry (DSC) quantitative manner.

(9) The Δn (optical anisotropy) was measured by an Abel tester at a test temperature of 25° C. and a test wavelength of 589 nm.

(10) The Δε (dielectric anisotropy) (Δε=ε//−ε⊥, wherein ε// is a dielectric constant parallel to the molecular axis, and −ε⊥ is a dielectric constant perpendicular to the molecular axis) was measured at a test temperature of 25±0.5° C.

(11) The γ1 (rotary viscosity) was measured by INSTEC:ALCTIRI under the test conditions of 25±0.5° C. with a 20 μm parallel box.

(12) The η (kinetic viscosity) was measured by an E-type viscometer under the test conditions of 25±0.5° C.

(13) The V.sub.th (threshold voltage) was measured under the test conditions of C/1 KHz and VA5.8.

(14) Each component adopted by the liquid crystal composition in the following examples can be synthesized by a well-known method or can be obtained commercially, and each component of the obtained liquid crystal compositions meets the standards of electronic compounds after testing.

(15) Liquid crystal compositions in the following examples were obtained by mixing each component according to the proportion of each component (the general formula to which each component belongs is shown in the parentheses at the end of the component in each example) and by conventional preparation methods such as heating, ultrasonic wave, suspending, etc.

Example 1

(16) In this example, the liquid crystal composition includes components in the mass percentage content as shown in the following table, and its performance test results are listed in the following table.

(17) TABLE-US-00003 Component Content (%) Test 3CPP2 (III-11) 6 Cp (° C.) 80.5 3CPPC3 (II-23) 2 Δn 0.1059 3CWO2 (II-1) 11 Δε −3.07 2C1OWO2 (II-3) 5 η (cP, 25° C.) 14.5 3CC1OWO2 (II-4) 5 γ1 (mPa .Math. S) 115 3CCWO2 (II-2) 10 Tc (° C.) <−20 5CCWO2 (II-2) 7 V.sub.th (V) 2.236 V 3CC2 (III-1) 8 4CPWO2 (IV-2) 4 5PP1 (II-3) 13 3CCV1 (II-1) 7.5 2CWO2 (II-1) 8.5 4CWO2 (II-1) 3 2CCP2V1 (I-5) 6 3CCP2V1 (I-5) 4

Example 2

(18) In this example, the liquid crystal composition includes components in the mass percentage content as shown in the following table, and its performance test results are listed in the following table.

(19) TABLE-US-00004 Component Content (%) Test 3CGP2 (III-13) 6 Cp (° C.) 82.3 3CPGP3 (III-21) 2 Δn 0.1052 3CWO2 (II-1) 11 Δε −3.13 2CC1OWO2 (I-4) 5 η (cP, 25° C.) 14.6 3CC1OWO2 (II-4) 5 γ1 (mPa .Math. S) 118 3CCWO2 (II-2) 8 Tc (° C.) <−20 5CCWO2 (II-2) 4 V.sub.th (V) 2.225 3CC2 (III-1) 8 4CPWO2 (IV-2) 4 5PP1 (III-3) 13 3CCV1 (III-1) 7.5 2CWO2 (II-1) 8.5 4CWO2 (II-1) 8 2CCP2V1 (I-5) 6 3CCP2V1 (I-5) 4

Example 3

(20) In this example, the liquid crystal composition includes components in the mass percentage content as shown in the following table, and its performance test results are listed in the following table.

(21) TABLE-US-00005 Component Content (%) Test 3CPO2 (III-2) 9 Cp (° C.) 78.8 3CCP2V1 (I-5) 10.5 Δn 0.1093 3CWO2 (I-1) 5 Δε −2.19 5CWO2 (II-1) 8 η (cP, 25° C.) 15.2 2CPWO2 (IV-2) 7 γ1 (mPa .Math. S) 118 3CPWO4 (IV-2) 8.5 Tc (° C.) <−20 3CCWO2 (II-2) 10 V.sub.th (V) 2.526 4CCWO2 (II-2) 5 3CC2 (III-1) 20 4CC3 (III-1) 9 VCW04 (II-1) 8

Example 4

(22) In this example, the liquid crystal composition includes components in the mass percentage content as shown in the following table, and its performance test results are listed in the following table.

(23) TABLE-US-00006 Component Content (%) Test 3VCPO2 (III-2) 9 Cp (° C.) 79.6 3CCP2V1 (I-5) 10.5 Δn 0.115 3PWO2 (IV-1) 3 Δε −2.59 5PWO2 (IV-1) 8 η (cP, 25° C.) 16.2 2CPWO2 (IV-2) 7 γ1 (mPa .Math. S) 126 3CPWO4 (IV-2) 8.5 Tc (° C.) <−20 3CCWO2 (II-2) 10 V.sub.th (V) 2.435 4CCWO2 (II-2) 5 3CC2 (III-1) 20 4CC3 (III-1) 9 VCWO4 (II-1) 10

Example 5

(24) In this example, the liquid crystal composition includes components in the mass percentage content as shown in the following table, and its performance test results are listed in the following table.

(25) TABLE-US-00007 Component Content (%) Test 3CPP2 (III-11) 9.5 Cp (° C.) 83.8 3C1OWO2 (II-3) 5.5 Δn 0.1216 2PPWO2 (IV-3) 4 Δε −3.21 3PPWO2 (IV-3) 6.5 η (cP, 25° C.) 16.6 4PPWO2 (IV-3) 6.5 γ1 (mPa .Math. S) 118 3PPO2 (III-3) 5 Tc (° C.) <−20 3CCV (III-1) 18.5 V.sub.th (V) 2.245 3CCV1 (III-1) 12 2C1OWO2 (II-3) 6.5 4C1OWO2 (II-3) 6 2CCP2V (I-2) 5 3CCP2V (I-2) 3.5 1VCPWO2 (IV-2) 2 1V2PWO2 (IV-1) 6 1VCPWO4 (IV-2) 3.5

Example 6

(26) In this example, the liquid crystal composition includes components in the mass percentage content as shown in the following table, and its performance test results are listed in the following table.

(27) TABLE-US-00008 Component Content (%) Test 3CPP2 (III-11) 9.5 Cp (° C.) 83.2 3C1OWO2 (II-3) 5 Δn 0.1085 2CC1OWO2 (II-4) 2 Δε −2.85 3CC1OWO2 (II-4) 4 η (cP, 25° C.) 15.7 4CC1OWO2 (II-4) 1 γ1 (mPa .Math. S) 113 3CCV (III-1) 20.5 Tc (° C.) <−20 3CCV1 (III-1) 12 V.sub.th (V) 2.375 2C1OWO2 (II-3) 7.5 4C1OWO2 (II-3) 8 2CCP2V (I-2) 5 3CCP2V1 (I-5) 3.5 1VCPWO2 (IV-2) 7 1V2PWO2 (IV-1) 7.5 1VCPWO4 (IV-2) 7.5

Example 7

(28) In this example, the liquid crystal composition includes components in the mass percentage content as shown in the following table, and its performance test results are listed in the following table.

(29) TABLE-US-00009 Component Content (%) Test 3CC1OC2 (III-16) 9.5 Cp (° C.) 81.8 3C1OWO2 (II-3) 5 Δn 0.1050 2PWWO2 (IV-4) 2 Δε −3.12 3PWWO2 (IV-4) 4 η (cP, 25° C.) 15.8 4PWWO2 (IV-4) 1 γ1 (mPa .Math. S) 112 3CCV (III-1) 20.5 Tc (° C.) <−20 3CCV1 (III-1) 12 V.sub.th (V) 2.318 2C1OWO2 (II-3) 7.5 4C1OWO2 (II-3) 8 2CCP2V (I-2) 2 3CCP3V (I-3) 6.5 1VCPWO2 (IV-2) 7 1V2PWO2 (IV-1) 7.5 1VCPWO4 (IV-2) 7.5

Example 8

(30) In this example, the liquid crystal composition includes components in the mass percentage content as shown in the following table, and its performance test results are listed in the following table.

(31) TABLE-US-00010 Component Content (%) Test 3CPPC3 (III-23) 2 Cp (° C.) 78.9 3CPP2 (III-11) 4 Δn 0.1126 3CWO2 (II-1) 11 Δε −3.37 2C1OWO2 (II-3) 5 η (cP, 25° C.) 14.2 3C1OWO2 (II-3) 5 γ1 (mPa .Math. S) 122 3CCWO2 (II-2) 8 Tc (° C.) <−20 5CCWO2 (II-2) 10 V.sub.th (V) 2.237 3CC2 (III-1) 8 4C1OWO2 (II-3) 4 5PP1 (III-3) 8 3CCV1 (III-1) 7.5 2CWO2 (II-1) 5.5 4CWO2 (II-1) 5 3PWP4 2 2CCP1V1 (I-8) 6 3CCP2V1 (I-5) 4 2CCP3V1 (I-6) 5

Example 9

(32) In this example, the liquid crystal composition includes components in the mass percentage content as shown in the following table, and its performance test results are listed in the following table.

(33) TABLE-US-00011 Component Content (%) Test 3CCPV2 (I-7) 9 Cp (° C.) 82.3 2CCP2V1 (I-5) 9 Δn 0.117 2CCPV1 (I-4) 4 Δε −3.06 3CCEPC3 (III-22) 1 η (cP, 25° C.) 15.2 3CPWO4 (IV-2) 4 γ1 (mPa .Math. S) 125 5C1OWO2 (II-3) 11 Tc (° C.) <−20 3CC1OWO2 (II-4) 10 V.sub.th (V) 2.355 2CC1OWO2 (II-4) 9 4CCWO2 (II-2) 3 3CC2 (III-1) 21 5PP1 (III-3) 13 2C1OWO2 (I-3) 5 3PWO2 (IV-1) 1

Comparative Example 1

(34) In this example, the liquid crystal composition includes components in the mass percentage content as shown in the following table, and its performance test results are listed in the following table.

(35) TABLE-US-00012 Component Content (%) Test 3CPP2 (III-11) 6 Cp (° C.) 73.9 3CPPC3 (III-23) 2 Δn 0.1068 3CWO2 (II-1) 11 Δε −3.01 2C1OWO2 (II-3) 5 η (cP, 25° C.) 14.7 3CC1OWO2 (II-4) 5 γ1 (mPa .Math. S) 122 3CCWO2 (II-2) 10 Tc (° C.) <−10 5CCWO2 (II-2) 7 V.sub.th (V) 2.365 3CC2 (III-1) 8 4CPWO2 (IV-2) 4 5PP1 (III-3) 13 3CCV1 (III-1) 7.5 2CWO2 (II-1) 8.5 4CWO2 (II-1) 3 2CPP2V1 (III-11) 6 3CPP2V1 (III-11) 4

(36) As is seen from a comparison of Examples 1 to 9 with Comparative example 1, the liquid crystal compound of the present disclosure has a small rotational viscosity, a wide temperature range of nematic phase and a short response time.

(37) The Applicant declares that the above are only specific embodiments of the present disclosure and are not intended to limit the scope of the present disclosure. It is easy for those skilled in the art to conceive modifications or substitutions within the technical scope of the present disclosure. These modifications or substitutions are within the scope of the present disclosure.