Liquid crystal composition, liquid crystal medium, and electro-optical display element

Abstract

The present application provides a liquid crystal composition, a liquid crystal medium, and an electro-optical display element. The liquid crystal composition includes at least one or more compounds having the formula I. By introducing groups such as X, K1, K2, A1, A2, R1, and R2 into the structure of the formula I, the dipole moments of the compound molecules are oriented in the same direction, reducing the polarity of the compounds, thereby reducing the viscosity of the compounds, increasing the response speed, shortening the response time, and improving the display effect and performance of the electro-optical display element.

Description

Technical Field

[0001] The present application relates to the field of display technologies, and particularly to a liquid crystal composition, a liquid crystal medium, and an electro-optical display element. Background Art

[0002] Liquid crystal compounds are widely used in displays of electronic devices including but not limited to watches, mobile phones, televisions, and computers. The contrast ratio and response time of the display are affected by the optical, electrical, and mechanical properties of the liquid crystal compounds, resulting in poor contrast ratio and long response time of the display, thereby affecting the display effect and performance of the display. For example: when the voltage is 0V, the alignment direction of liquid crystal molecules in a VA (vertical alignment mode) display is perpendicular to the glass substrate, and the incident light perpendicular to the glass substrate cannot pass through, presenting a good dark state effect. Therefore, VA displays usually have negative dielectric anisotropy (Δε) and good contrast ratio, but their response time is long and the response speed is slow. The contrast ratio and response speed of IPS and FFS displays are not good.

[0003] However, the optical, electrical, and mechanical properties of liquid crystal compounds depend on their molecular structures and the structures of the substituent groups. Therefore, in order to improve the display effect and performance of the display, it is urgent to develop liquid crystal materials with faster response and higher contrast ratio. Summary of the Invention

[0004] The present application provides a liquid crystal composition, a liquid crystal medium, and an electro-optical display element to solve the technical problem that the display effect of the display is insufficient due to the small polarity, large viscosity, and slow response speed of the liquid crystal material.

[0005] The first aspect of the present application is to provide a liquid crystal composition, which comprises at least one or more compounds having formula I:

[0006]

[0007] wherein, A1 and A2 are each independently a single bond, O, or S;

[0008] X is a single bond, -O-, -S-, -CH2-, -CH2CH2-, or -CF2-;

[0009] K1 and K2 are each independently H or F;

[0010] R1 and R2 are each independently H, F, Cl, Br, I, CN, SCN, NCS, CF3, or SF5, or each independently is C 1-15 alkyl, C 1-15 alkoxy, C 2-15 alkenyl, C 2-15 alkenyloxy, C 2-15 alkynyl, or C 2-15alkoxy, and C 1-15 alkyl, C 1-15 alkoxy, C 2-15 alkenyl, C 2-15 alkenyloxy, C 2-15 alkynyl or C 2-15 the terminal group of alkoxy can be substituted by H, CN or CF3, and / or C 1-15 alkyl, C 1-15 alkoxy, C 2-15 alkenyl, C 2-15 alkenyloxy, C 2-15 alkynyl or C 2-15 at least one CH2 group of alkoxy can be substituted by -O-, -S-, -SO2-, -CO-, -C(O)O-, -OC(O)-, -OC(O)O-, -CF2O-, -OCF2-, -CH2CH2-, -CF2CF2-, -CF2CH2-, -CH2CF2-, -CHF-CHF-, -CH2O, -OCH2-, -CF=CH-, -CH=CF-, -CF=CF-, -CH=CH- or -C≡C-, and / or C 1-15 alkyl, C 1-15 alkoxy, C 2-15 alkenyl, C 2-15 alkenyloxy, C 2-15 alkynyl or C 2-15 at least one H of alkoxy can be substituted by F, Cl, Br or I.

[0011] Optionally, in some embodiments of the present application, X is -O- or -S-.

[0012] Optionally, in some embodiments of the present application, A1 and A2 are each independently S or O.

[0013] Optionally, in some embodiments of the present application, at least one of K1 and K2 is F.

[0014] Optionally, in some embodiments of the present application, R1 and R2 are each independently C 1-7 alkyl, C 1-7 alkoxy, C 2-7 alkenyl, C 2-7 alkenyloxy, C 2-7 alkynyl or C 2-7 alkoxy.

[0015] Optionally, in some embodiments of the present application, the compound having formula I has the following structural formula:

[0016]

[0017] any one of, wherein,

[0018] R7 is C 1-15 alkyl, C 2-15 alkenyl or C 2-15 alkynyl, and one or two CH2 groups in R7 can be replaced by -O-, -CO-, -C(O)O-, -OC(O)-, -CF2O-, -OCF2-, -CH2O or -OCH2-;

[0019] R2 is H, F, Cl, Br, I, CN, SCN, NCS, CF3 or SF5, or is C 1-15 alkyl, C 1-15 alkoxy, C 2-15 alkenyl, C 2-15 alkenyloxy, C 2-15 alkynyl or C 2-15 alkynyloxy, and the terminal group of C 1-15 alkyl, C 1-15 alkoxy, C 2-15 alkenyl, C 2-15 alkenyloxy, C 2-15 alkynyl or C 2-15 alkynyloxy can be replaced by H, CN or CF3, and / or C 1-15 alkyl, C 1-15 alkoxy, C 2-15 alkenyl, C 2-15 alkenyloxy, C 2-15 alkynyl or C 2-15 alkynyloxy has at least one CH2 group that can be replaced by -O-, -S-, -SO2-, -CO-, -C(O)O-, -OC(O)-, -OC(O)O-, -CF2O-, -OCF2-, -CH2CH2-, -CF2CF2-, -CF2CH2-, -CH2CF2-, -CHF-CHF-, -CH2O, -OCH2-, -CF=CH-, -CH=CF-, -CF=CF-, -CH=CH- or -C≡C-, and / or C 1-15 alkyl, C 1-15 alkoxy, C 2-15 alkenyl, C 2-15 alkenyloxy, C 2-15 alkynyl or C 2-15 alkynyloxy has at least one H that can be replaced by F, Cl, Br or I.

[0020] Optionally, in some embodiments of the present application, the IB is selected from the following structural formulas:

[0021]

[0022]

[0023] Any one of... And / or, the IE is selected from the following structural formulas:

[0024]

[0025]

[0026] Any one of... And / or, the IH is selected from the following structural formulas:

[0027]

[0028] Any one of... And / or, the IN is selected from the following structural formulas:

[0029]

[0030] Any one of... The IQ is selected from the following structural formulas:

[0031]

[0032]

[0033] Any one of... And / or, the IT is selected from the following structural formulas:

[0034]

[0035] Any one of...

[0036] Optionally, in some embodiments of the present application, the liquid crystal composition further comprises at least one or more compounds having Formula II and / or at least one or more compounds having Formula III:

[0037] R3 - R' - R4 Formula II.

[0038] Wherein, R3 and R4 are each independently C 1-10 alkyl, C 1-10 alkoxy, C 2-10 alkenyl, C 2-10 alkenyloxy, C 2-10 alkynyl or C 2-10 alkynyloxy, and at least one H atom in R3 and R4 can be substituted by F, Cl, Br or I;

[0039] R' is:

[0040] R5 - R"—R6 Formula III.

[0041] Among them, R5 and R6 are each independently C 1-10 alkyl, C 1-10 alkoxy, C 2-10 alkenyl, C 2-10 alkenyloxy, C 2-10 alkynyl or C 2-10 alkynyloxy, and at least one H atom in R5 and R6 can be substituted by F, Cl, Br or I.

[0042] R” is:

[0043] Optionally, in some embodiments of the present application, the mass percentage of the compound having formula I is 1% - 50%, the mass percentage of the compound having formula II is 1% - 90%, and the mass percentage of the compound having formula III is 1% - 90%.

[0044] Optionally, in some embodiments of the present application, the mass percentage of the compound having formula I is 1% - 25%, the mass percentage of the compound having formula II is 10% - 70%, and the mass percentage of the compound having formula III is 10% - 70%.

[0045] The second aspect of the present application is to provide a liquid crystal medium, which comprises the above liquid crystal composition.

[0046] The third aspect of the present application is to provide an electro-optical display element, which comprises a liquid crystal layer made of the above liquid crystal medium.

[0047] The present application provides a liquid crystal composition, which contains a compound having formula I. By introducing groups such as X, K1, K2, A1, A2, R1 and R2 into the structure of formula I, the dipole moments of the compound molecules are oriented in the same direction, reducing the polarity of the compound, thereby reducing the viscosity of the compound, improving the response speed, shortening the response time, and improving the display effect and performance of the electro-optical display element. Detailed Embodiments

[0048] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative efforts belong to the scope of protection of the present application. In addition, it should be understood that the specific embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0049] The present application provides a liquid crystal composition, a liquid crystal medium, and an electro-optical display element, which will be described in detail below. It should be noted that the description order of the following embodiments does not limit the preferred order of the embodiments of the present application. And in the following embodiments, each embodiment has its own emphasis. For parts not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0050] An embodiment of the present application provides a liquid crystal composition, which includes at least one or more compounds having formula I:

[0051]

[0052] Wherein, A1 and A2 are each independently a single bond, O or S.

[0053] X is a single bond, -O-, -S-, -CH2-, -CH2CH2- or -CF2-. In one embodiment, X is represented as O, introducing an oxifluorene structure into formula I, which is beneficial to increasing the polarity of the liquid crystal compound. In another embodiment, X is represented as S, introducing a thiofluorene structure into formula I, which is beneficial to increasing the solubility of the liquid crystal compound.

[0054] K1 and K2 are each independently H or F. In one embodiment, at least one of K1 and K2 is F; when both K1 and K2 are F, it is beneficial to increase the polarity of the liquid crystal compound. In a specific example, A1 and A2 are each independently O. X is -O-. K1 and K2 are both F. As can be seen from formula I, F and O are on the same side of the molecule, making the dipole moment of the molecule in the same direction, which is beneficial to increasing the polarity of the liquid crystal compound, thereby beneficial to reducing the viscosity of the liquid crystal compound and further improving the response speed of the liquid crystal compound.

[0055] R1 and R2 are each independently H, F, Cl, Br, I, CN, SCN, NCS (isothiocyanato), CF3 or SF5, or each independently is C 1-15 alkyl, C 1-15 alkoxy, C 2-15 alkenyl, C 2-15 alkenyloxy, C 2-15 alkynyl or C 2-15 alkynyloxy, and the terminal groups of C 1-15 alkyl, C 1-15 alkoxy, C 2-15 alkenyl, C 2-15 alkenyloxy, C 2-15 alkynyl or C 2-15 alkynyloxy can be substituted by H, CN or CF3, and / or C 1-15 alkyl, C 1-15 alkoxy, C 2-15 alkenyl, C 2-15 alkenyloxy, C2-15 An alkynyl group or C 2-15 In the alkynyloxy group, at least one CH2 group can be substituted by -O-, -S-, -SO2-, -CO-, -C(O)O-, -OC(O)-, -OC(O)O-, -CF2O-, -OCF2-, -CH2CH2-, -CF2CF2-, -CF2CH2-, -CH2CF2-, -CHF-CHF-, -CH2O, -OCH2-, -CF═CH-, -CH═CF-, -CF═CF-, -CH═CH- or -C≡C-. And / or C 1-15 An alkyl group, C 1-15 An alkoxy group, C 2-15 An alkenyl group, C 2-15 An alkenyloxy group, C 2-15 An alkynyl group or C 2-15 In the alkynyloxy group, one or more H atoms can be substituted by F, Cl, Br or I, and preferably one or more H atoms are substituted by F or Cl.

[0056] It should be noted that:

[0057] The above-mentioned "alkyl group", "alkenyl group" or "alkynyl group" means a straight-chain or branched-chain aliphatic hydrocarbon group having 1 to 15 (i.e., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15) carbon atoms.

[0058] R1 and R2 in Formula I each independently represent an alkyl group, and these alkyl groups can be straight-chain or branched-chain. Each of these groups is preferably straight-chain, having 1, 2, 3, 4, 5, 6 or 7 carbon atoms and correspondingly preferably methyl, ethyl, propyl, butyl, pentyl, hexyl or heptyl.

[0059] R1 and R2 in formula I each independently represent an alkenyl or alkynyl group having 2 to 15 carbon atoms, which alkenyl or alkynyl groups may be straight-chain or branched-chain and have at least one carbon-carbon double bond or carbon-carbon triple bond. Preferably, they are straight-chain alkenyl or alkynyl groups having 2 to 7 carbon atoms. Specifically, they are vinyl, prop-1-enyl, prop-2-enyl, but-1-enyl, but-2-enyl, but-3-enyl, pent-1-enyl, pent-2-enyl, pent-3-enyl, pent-4-enyl, hex-1-enyl, hex-2-enyl, hex-3-enyl, hex-4-enyl, hex-5-enyl, hept-1-enyl, hept-2-enyl, hept-3-enyl, hept-4-enyl, hept-5-enyl, hept-6-enyl, ethynyl, prop-1-ynyl, prop-2-ynyl, but-1-ynyl, but-2-ynyl, but-3-ynyl, pent-1-ynyl, pent-2-ynyl, pent-3-ynyl, pent-4-ynyl, hex-1-ynyl, hex-2-ynyl, hex-3-ynyl, hex-4-ynyl, hex-5-ynyl, hept-1-ynyl, hept-2-ynyl, hept-3-ynyl, hept-4-ynyl, hept-5-ynyl or hept-6-ynyl, and the alkenyl groups may be E and Z isomers. Among the alkenyl and alkynyl groups, prop-2-enyl, but-2-enyl, but-3-enyl, pent-2-enyl, pent-3-enyl, pent-4-enyl, prop-2-ynyl, but-2-ynyl, but-3-ynyl, pent-2-ynyl, pent-3-ynyl or pent-4-ynyl are preferred.

[0060] Groups or substituents of the compound having formula I according to the above embodiments of the present application or the compound having formula I itself in the form of an optically active or stereoisomeric group, substituent or compound having an asymmetric center or chiral center are also included within the scope of protection of the present application. The above compound having formula I can exist in the form of isomers, such as pure enantiomers, diastereomers, E or Z isomers or as a mixture of multiple isomers in any desired ratio, such as a racemate, E / Z isomer mixture.

[0061] In one embodiment, when A1 in formula I above is O, R1 and R2 preferably represent an alkyl group having 1 to 7 carbon atoms, particularly preferably 2 to 5 carbon atoms. When A2 is a single bond or O, R2 preferably represents an alkyl group, alkenyl group or alkynyl group, particularly preferably an alkyl group having 1 to 7 carbon atoms. The total number of carbon atoms in R1 and R2 is preferably 4, 5, 6, 7, 8, 9, 10, particularly preferably 5, 6, 7, 8, 9.

[0062] In another embodiment, when A1 in Formula I is a single bond, R1 and R2 preferably represent alkyl groups having 1 to 7 carbon atoms, particularly preferably 2 to 5 carbon atoms. When A2 is a single bond or O, R2 preferably represents an alkyl group, an alkenyl group or an alkynyl group, particularly preferably an alkyl group having 1 to 7 carbon atoms. The total number of carbon atoms in R1 and R2 is preferably 4, 5, 6, 7, 8, 9, 10, particularly preferably 5, 6, 7, 8, 9.

[0063] In some embodiments, R1 and R2 each independently represent C 2-7 alkyl, C 3-6 alkenyl, C 3-6 alkynyl or CF3, and one or two CH2 groups in the R1 and R2 groups are replaced by -O-, -CO-, -C(O)O-, -OC(O)-, -CF2O-, -OCF2-, -CH2O or -OCH2-.

[0064] In other embodiments of the present application, R1 and R2 are each independently C 1-7 alkyl, C 1-7 alkoxy, C 2-7 alkenyl, C 2-7 alkenyloxy, C 2-7 alkynyl or C 2-7 alkynyloxy, and at least one or more CH2 groups in C 1-7 alkyl, C 1-7 alkoxy, C 2-7 alkenyl, C 2-7 alkenyloxy, C 2-7 alkynyl or C 2-7 alkynyloxy can be replaced by -O-, -C(O)O-, -OC(O)-, -CF2O-, -OCF2-, -CH2CH2-, -CH2O, -OCH2-, -CH=CH- or -C≡C-; and one or more H in C 1-7 alkyl, C 1-7 alkoxy, C 2-7 alkenyl, C 2-7 alkenyloxy, C 2-7 alkynyl or C 2-7 alkynyloxy can be replaced by F. In one embodiment, R1 and R2 each independently represent H or F. When R1 and R2 each independently represent F, it is beneficial to increase the polarity of the liquid crystal compound. In another embodiment, R1 and R2 are each independently C 1-7 alkyl, C 1-7 alkoxy, C 2-7 alkenyl, C 2-7 alkenyloxy, C 2-7 alkynyl or C 2-7 alkynyloxy.

[0065] In some other embodiments of the present application, the compound having the formula I has the following structural formula:

[0066]

[0067] any one of, wherein R7 is C 1-15 alkyl, C 2-15 alkenyl or C 2-15 alkynyl, and one or two CH2 groups in R7 can be replaced by -O-, -CO-, -C(O)O-, -OC(O)-, -CF2O-, -OCF2-, -CH2O or -OCH2-. R2 is H, F, Cl, Br, I, CN, SCN, NCS, CF3 or SF5, or is C 1-15 alkyl, C 1-15 alkoxy, C 2-15 alkenyl, C 2-15 alkenyloxy, C 2-15 alkynyl or C 2-15 alkynyloxy, and the terminal group of C 1-15 alkyl, C 1-15 alkoxy, C 2-15 alkenyl, C 2-15 alkenyloxy, C 2-15 alkynyl or C 2-15 alkynyloxy can be replaced by H, CN or CF3, and / or C 1-15 alkyl, C 1-15 alkoxy, C 2-15 alkenyl, C 2-15 alkenyloxy, C 2-15 alkynyl or C 2-15 alkynyloxy has at least one CH2 group that can be replaced by -O-, -S-, -SO2-, -CO-, -C(O)O-, -OC(O)-, -OC(O)O-, -CF2O-, -OCF2-, -CH2CH2-, -CF2CF2-, -CF2CH2-, -CH2CF2-, -CHF-CHF-, -CH2O, -OCH2-, -CF=CH-, -CH=CF-, -CF=CF-, -CH=CH- or -C≡C-, and / or C 1-15 alkyl, C 1-15 alkoxy, C 2-15 alkenyl, C 2-15 alkenyloxy, C 2-15 alkynyl or C 2-15 alkynyloxy has at least one H that can be replaced by F, Cl, Br or I.

[0068] In the structural formula of the above IA-IX compounds, an oxofluorene structure or a thiofluorene structure is introduced, and K1, K2, A1, and A2 are optimized, and preferred groups that are beneficial to improving the polarity of the liquid crystal compound are selected to obtain compounds with high dielectric, high polarity, and low viscosity. It should be noted that the liquid crystal composition may include one or more of the above IA-IX compounds.

[0069] In some other embodiments of the present application, IB is selected from the following structural formulas:

[0070] Any one of them. In the structural formulas of the above IB1-16, an oxofluorene structure is introduced, and A1 and A2 are single bonds or O, and K1 and K2 are each independently F, which is beneficial to improving the polarity of the compound, thereby reducing the viscosity. The above compounds have the advantages of high dielectric, high polarity, and low viscosity. IE is selected from the following structural formulas:

[0071]

[0072] Any one of them. In the structural formulas of the above IE1-16, an oxofluorene structure is introduced, and A1 and A2 are single bonds or O, and K1 and K2 are each independently F, which is beneficial to improving the polarity of the compound, thereby reducing the viscosity. The above compounds have the advantages of high dielectric, high polarity, and low viscosity.

[0073] IH is selected from the following structural formulas:

[0074]

[0075]

[0076] Any one of them. In the structural formulas of the above IH1-16, an oxofluorene structure is introduced, and A1 and A2 are single bonds or O, and K1 and K2 are each independently F, which is beneficial to improving the polarity of the compound, thereby reducing the viscosity. The above compounds have the advantages of high dielectric, high polarity, and low viscosity.

[0077] IN is selected from the following structural formulas:

[0078]

[0079] Any one of them. In the structural formulas of the above IN1-16, a thiofluorene structure is introduced, and A1 and A2 are single bonds or O, and K1 and K2 are each independently F, which is beneficial to improving the polarity of the compound, thereby reducing the viscosity. The above compounds have the advantages of high dielectric, high polarity, and low viscosity.

[0080] IQ is selected from the following structural formulas:

[0081] Any one of them. In the structural formulas of the above IQ1-16, a dibenzothiophene structure is introduced, and A1 and A2 are single bonds or O, and K1 and K2 are each independently F, which is beneficial to improving the polarity of the compound and thus reducing the viscosity. The above compounds have the advantages of high dielectric, high polarity and low viscosity.

[0082] IT is selected from the following structural formulas:

[0083] Any one of them. In the structural formulas of the above IT1-16, a dibenzothiophene structure is introduced, and A1 and A2 are single bonds or O, and K1 and K2 are each independently F, which is beneficial to improving the polarity of the compound and thus reducing the viscosity. The above compounds have the advantages of high dielectric, high polarity and low viscosity.

[0084] In one embodiment, the compound having the formula I can be prepared by the following method:

[0085] S1. Perform an addition reaction on the first compound to form an addition product, wherein the structural formula of the first compound is: The structural formula of the addition product is:

[0086] S2. Perform an oxidation reaction on the addition product to obtain an oxidation product, wherein the structural formula of the oxidation product is:

[0087] S3. Perform a cross-coupling reaction on the second compound and the oxidation product to form a coupling product, wherein the structural formula of the second compound is: The structural formula of the coupling product is:

[0088] S4. Perform a condensation reaction on the coupling product to form the target product, and its structural formula is:

[0089] The reaction process is as follows:

[0090]

[0091] In the structural formulas of the first compound, the addition product, the oxidation product, the second compound, the coupling product and the target product, A1 and A2 are each independently a single bond, O or S.

[0092] K1 and K2 are each independently H or F.

[0093] R1 and R2 are each independently H, F, Cl, Br, I, CN, SCN, NCS (isothiocyanato), CF3 or SF5, or are each independently C 1-15 alkyl, C 1-15 alkoxy, C 2-15 alkenyl, C 2-15 alkenyloxy, C 2-15 alkynyl or C 2-15 alkynyloxy, and the terminal group of the C 1-15 alkyl, C 1-15 alkoxy, C 2-15 alkenyl, C 2-15 alkenyloxy, C 2-15 alkynyl or C 2-15 alkynyloxy can be substituted by H, CN or CF3; and / or C 1-15 alkyl, C 1-15 alkoxy, C 2-15 alkenyl, C 2-15 alkenyloxy, C 2-15 alkynyl or C 2-15 alkynyloxy can have at least one CH2 group substituted by -O-, -S-, -SO2-, -CO-, -C(O)O-, -OC(O)-, -OC(O)O-, -CF2O-, -OCF2-, -CH2CH2-, -CF2CF2-, -CF2CH2-, -CH2CF2-, -CHF-CHF-, -CH2O, -OCH2-, -CF=CH-, -CH=CF-, -CF=CF-, -CH=CH- or -C≡C-, and / or C 1-15 alkyl, C 1-15 alkoxy, C 2-15 alkenyl, C 2-15 alkenyloxy, C 2-15 alkynyl or C 2-15 alkynyloxy can have one or more H substituted by F, Cl, Br or I.

[0094] In another embodiment, the compound having formula I can be prepared by the following method:

[0095] S10. Perform an addition reaction on the first compound to form an addition product, wherein the structural formula of the first compound is: The structural formula of the addition product is:

[0096] S20. Perform an oxidation reaction on the addition product to obtain an oxidation product, wherein the structural formula of the oxidation product is:

[0097] S30. Perform a cross-coupling reaction on the second compound and the oxidation product to form a coupling product, wherein the structural formula of the second compound is: The structural formula of the coupling product is:

[0098] S40. The coupling product is subjected to a condensation reaction in a weak base to form a first intermediate product, and its structural formula is:

[0099] S50. The first intermediate product is subjected to a rearrangement reaction to form a second intermediate product, and its structural formula is:

[0100]

[0101] S60. The second intermediate product is subjected to a condensation reaction to obtain the target product, and its structural formula is:

[0102]

[0103] The reaction process is:

[0104]

[0105] In the structural formulas of the above first compound, addition product, oxidation product, second compound, coupling product, first intermediate product, second intermediate product and target product, A1 and A2 are each independently a single bond, O or S.

[0106] K1 and K2 are each independently H or F.

[0107] R1 and R2 are each independently H, F, Cl, Br, I, CN, SCN, NCS (isothiocyanato), CF3 or SF5, or each independently is a C 1-15 alkyl group, a C 1-15 alkoxy group, a C 2-15 alkenyl group, a C 2-15 alkenyloxy group, a C 2-15 alkynyl group or a C 2-15 alkynyloxy group, and the terminal group of the C 1-15 alkyl group, a C 1-15 alkoxy group, a C 2-15 alkenyl group, a C 2-15 alkenyloxy group, a C 2-15 alkynyl group or a C 2-15 alkynyloxy group can be substituted by H, CN or CF3; and / or a C 1-15 alkyl group, a C 1-15 alkoxy group, a C 2-15 alkenyl group, a C 2-15 alkenyloxy group, a C 2-15 alkynyl group or a C 2-15At least one CH2 group in the alkoxy group can be substituted by -O-, -S-, -SO2-, -CO-, -C(O)O-, -OC(O)-, -OC(O)O-, -CF2O-, -OCF2-, -CH2CH2-, -CF2CF2-, -CF2CH2-, -CH2CF2-, -CHF-CHF-, -CH2O, -OCH2-, -CF═CH-, -CH═CF-, -CF═CF-, -CH═CH- or -C≡C-, and / or C 1-15 alkyl, C 1-15 alkoxy, C 2-15 alkenyl, C 2-15 alkenyloxy, C 2-15 alkynyl or C 2-15 One or more H atoms in the alkoxy group can be substituted by F, Cl, Br or I.

[0108] In other embodiments of the present application, the liquid crystal composition comprises: at least one or more compounds having formula I, at least one or more compounds having formula II and / or at least one or more compounds having formula III:

[0109] The structure of the compound having formula I is as described above, so it will not be repeated here.

[0110] The compound having formula II is:

[0111] R3-R'-R4 Formula II.

[0112] Wherein, R3 and R4 are each independently C 1-10 alkyl, C 1-10 alkoxy, C 2-10 alkenyl, C 2-10 alkenyloxy, C 2-10 alkynyl or C 2-10 alkoxy, and at least one H atom in R3 and R4 can be substituted by F, Cl, Br or I.

[0113] R' is:

[0114] By adding the compound having formula II to the liquid crystal composition, it is beneficial to reduce the viscosity of the liquid crystal composition, increase the optical anisotropy (Δn) of the liquid crystal composition and improve the clearing point (Tni) of the composition.

[0115] The compound having formula III is:

[0116] R5—R''—R6 Formula III.

[0117] Wherein, R5 and R6 are each independently C 1-10 alkyl, C 1-10Alkoxy, C 2-10 Alkenyl, C 2-10 Alkenyloxy, C 2-10 Alkynyl or C 2-10 Alkynyloxy, and at least one H atom in R5 and R6 can be substituted by F, Cl, Br or I.

[0118] R” is:

[0119] By adding a compound having formula III to the liquid crystal composition, it is beneficial to reduce the viscosity of the liquid crystal composition, increase the dielectric of the liquid crystal composition, and improve the clearing point of the liquid crystal composition, thereby improving the low-temperature performance of the liquid crystal composition.

[0120] In some embodiments, by mass percentage, the components of the liquid crystal composition include: 1% - 50% of the compound having formula I, 1% - 90% of the compound having formula II, and 1% - 90% of the compound having formula III. In another embodiment, by mass percentage, the components of the liquid crystal composition include: 1% - 40% of the compound having formula I, 5% - 70% of the compound having formula II, and 5% - 70% of the compound having formula III. In other embodiments, by mass percentage, the components of the liquid crystal composition include: 1% - 25% of the compound having formula I, 10% - 70% of the compound having formula II, and 10% - 70% of the compound having formula III. It should be noted that in specific implementations, the liquid crystal composition may include one or more compounds having formula I. When there are multiple compounds having formula I, the mixing ratio of the multiple compounds having formula I in this embodiment is not limited and can be mixed in any ratio. The liquid crystal composition may also include one or more compounds having formula II. When there are multiple compounds having formula II, the mixing ratio of the multiple compounds having formula II in this embodiment is not limited and can be mixed in any ratio. The liquid crystal composition may further include one or more compounds having formula III. When there are multiple compounds having formula III, the mixing ratio of the multiple compounds having formula III in this embodiment is not limited and can be mixed in any ratio.

[0121] In some other embodiments of the present application, a liquid crystal medium is provided, which includes the above-mentioned liquid crystal composition. The liquid crystal composition is applied in the liquid crystal medium. The liquid crystal composition has advantages such as low viscosity, large polarity, and fast response, which is of positive significance for the development of display devices with fast response, and is suitable for the preparation of mixed liquid crystals, which is beneficial to improving the polarity of the liquid crystal medium, increasing the dielectric anisotropy of the liquid crystal medium, increasing the clearing point (Tni, unit: °C) of the liquid crystal medium, and improving the low-temperature performance of the liquid crystal medium. In some embodiments, the liquid crystal medium containing the liquid crystal composition provided by the embodiments of the present application is applied to a display in VA, ECB, PALC, FFS, or IPS mode to improve the display effect and performance of the display.

[0122] In some other embodiments of the present application, an electro-optical display element is provided, which includes a liquid crystal layer made of the above-mentioned liquid crystal medium. The electro-optical performance of the electro-optical display element is improved, thereby improving the display effect and performance of the electro-optical display element.

[0123] The following further illustrates the technical effects of the present application in combination with specific embodiments.

[0124] In the following embodiments, the liquid crystal composition is prepared by a thermal dissolution method, including the following steps:

[0125] S100. Weigh each component for preparing the liquid crystal composition by mass percentage. There is no specific requirement for the weighing and adding order, and usually, they are weighed and mixed in the order of increasing melting point of the liquid crystal compounds.

[0126] S200. Heat and stir at 60 °C - 100 °C to fully dissolve and mix each component.

[0127] S300. Cool to room temperature and encapsulate to obtain the target sample.

[0128] Unless otherwise specified, the percentages in this embodiment are all mass percentages, the temperature unit is °C; Tni represents the clearing point of the liquid crystal composition (unit: °C); Δn represents the optical anisotropy at 25 °C, n e is the refractive index of the extraordinary light; γ1 represents the rotational viscosity at 25 °C (unit: mPa·s); Δε represents the dielectric anisotropy at 25 °C, ε ⊥ is the dielectric constant perpendicular to the long axis of the liquid crystal molecules, K11 is the splay elastic constant, and K33 is the bend elastic constant.

[0129] Example 1

[0130] A liquid crystal composition is provided. By mass percentage, its components include:

[0131]

[0132]

[0133] The performance parameters of the liquid crystal composition of this example are as shown in Table 1 below:

[0134]

[0135] Table 1

[0136] The above liquid crystal composition has no crystallization after being placed at -20°C for 480 h.

[0137] Example 2

[0138] Provide a liquid crystal composition, by mass percentage, its components include:

[0139]

[0140]

[0141] The performance parameters of the liquid crystal composition of this example are as shown in Table 2 below:

[0142]

[0143] Table 2

[0144] The above liquid crystal composition has no crystallization after being placed at -20°C for 480 h.

[0145] Example 3

[0146] Provide a liquid crystal composition, by mass percentage, its components include:

[0147]

[0148]

[0149] The performance parameters of the liquid crystal composition of this example are as shown in Table 3 below:

[0150]

[0151]

[0152] Table 3

[0153] The above liquid crystal composition has no crystallization after being placed at -20°C for 480 h.

[0154] Example 4

[0155] Provide a liquid crystal composition, by mass percentage, its components include:

[0156]

[0157]

[0158] The performance parameters of the liquid crystal composition of this embodiment are shown in Table 4 below:

[0159]

[0160] Table 4

[0161] The above liquid crystal composition has no crystallization after being placed at -20°C for 480 h.

[0162] Example 5

[0163] Provided is a liquid crystal composition, by mass percentage, its components include:

[0164]

[0165]

[0166] The performance parameters of the liquid crystal composition of this embodiment are shown in Table 5 below:

[0167]

[0168] Table 5

[0169] The above liquid crystal composition has no crystallization after being placed at -20°C for 480 h.

[0170] Example 6

[0171] Provided is a liquid crystal composition, by mass percentage, its components include:

[0172]

[0173]

[0174] The performance parameters of the liquid crystal composition of this embodiment are shown in Table 6 below:

[0175]

[0176] Table 6

[0177] The above liquid crystal composition has no crystallization after being placed at -20°C for 480 h.

[0178] The performance parameters of the liquid crystal compositions of the above embodiments show that the overall polarity of the liquid crystal composition of this application is large, that is, Δε, and it plays a beneficial role in the response speed of the liquid crystal. For example, the response speed of displays such as IPS and FFS is judged according to γ1 / K 11 To judge, the smaller the ratio, the faster the response speed; the response speed of VA displays is judged according to γ1 / K 33It is judged that the smaller the ratio is, the faster the response speed is. From the performance parameters of the above embodiments, it can be shown that the liquid crystal composition of the present application has the advantages of large polarity, low viscosity, and fast response, etc.

[0179] The above provides a detailed introduction to the present application. Specific examples are used in this article to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A liquid crystal composition, characterized in that, Comprising at least one or more compounds having the formula I: Wherein, A1 and A2 are O; X is -S-; K1 and K2 are each independently H or F, and at least one of K1 and K2 is F; R1 and R2 are each independently ethyl, propyl, butyl or pentyl; The liquid crystal composition further comprises at least one or more compounds having the formula II and / or at least one or more compounds having the formula III: R3——R'——R4 Formula II, Among them, R3 and R4 are each independently C 1-10 alkyl, C 1-10 alkoxy, C 2-10 alkenyl, C 2-10 alkenyloxy, C 2-10 alkynyl or C 2-10 alkynyloxy, and at least one H atom in R3 and R4 can be substituted by F, Cl, Br or I; R’ is: R5——R"——R6 Formula III, Among them, R5 and R6 are each independently C 1-10 alkyl, C 1-10 alkoxy, C 2-10 alkenyl, C 2-10 alkenyloxy, C 2-10 alkynyl or C 2-10 alkynyloxy, and at least one H atom in R5 and R6 can be substituted by F, Cl, Br or I; "R” is:

2. The liquid crystal composition according to claim 1, characterized in that, The compound having the formula I has the following structural formula: any one of, wherein, R7 is ethyl, propyl, butyl or pentyl.

3. The liquid crystal composition according to claim 2, characterized in that, The IN is selected from the following structural formulas: any one of them.

4. The liquid crystal composition according to claim 1, wherein The mass percentage of the compound having the formula I is 1% - 50%, the mass percentage of the compound having the formula II is 1% - 90%, and the mass percentage of the compound having the formula III is 1% - 90%.

5. The liquid crystal composition according to claim 4, wherein The mass percentage of the compound having the formula I is 1% - 25%, the mass percentage of the compound having the formula II is 10% - 70%, and the mass percentage of the compound having the formula III is 10% - 70%.

6. A liquid crystal medium, characterized in that, Comprising the liquid crystal composition according to any one of claims 1 - 5.

7. An electro-optical display element, characterized in that, Comprising a liquid crystal layer, the liquid crystal layer being made of the liquid crystal medium according to claim 6.

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