Liquid crystal mixture and application thereof

Abstract

The present invention provides a negative liquid crystal mixture with a higher clearing point, which consists of a liquid crystal compound with a structure, a liquid crystal compound with a structure, a liquid crystal compound with a structure; a liquid crystal compound with a structure; a liquid crystal compound with a structure; a liquid crystal compound with a structure; a liquid crystal compound with a structure; a liquid crystal compound with a structure; a liquid crystal compound with a structure; a liquid crystal compound with a structure; a liquid crystal compound with a structure and a liquid crystal compound with a structure.

Description

[0001] This invention is a divisional of the prior invention patent with application number 2017110555753, and the application date is 2017.10.31. Technical Field

[0002] The present invention relates to the field of liquid crystal materials, and in particular to a liquid crystal compound, a liquid crystal mixture containing the liquid crystal compound, and applications thereof. Background Art

[0003] In the 1960s, RCA first discovered that electrical stimulation would change the light transmission mode of liquid crystals, and then applied this property to release liquid crystal display technology. Only then did liquid crystals gradually attract people's attention and quickly develop into various fields. In 1966, after DuPont used aromatic polyamide liquid crystals to synthesize Kevlar fibers, liquid crystal materials began the industrialization process. After decades of rapid development, liquid crystal materials have been widely used in many fields such as display technology, optical storage devices and solar cells due to their special properties. The research scope covers many fields such as chemistry, biology and information science, and has become one of the most popular and indispensable new materials in today's society.

[0004] With the rapid development of science and technology, people's requirements for the performance of liquid crystal materials will become higher and higher. It is expected that the development of liquid crystal materials in the future will mainly focus on the following aspects: (1) Exploring new processes for preparing existing liquid crystal materials, reducing the generation of by-products and harmful substances, and reducing production costs; (2) Modifying the performance of existing liquid crystal materials, such as reducing the requirements for ambient temperature and improving the color diversity of liquid crystal materials for display; (3) Preparing new functional liquid crystal materials to meet the high-standard use requirements in multiple fields, such as new liquid crystal materials for display, new optoelectronic liquid crystal storage materials in the field of information engineering, and new medicinal liquid crystal materials in the field of bioengineering.

[0005] Liquid crystal displays can be divided into two driving modes: passive matrix (also known as passive matrix or simple matrix) and active matrix (also known as active matrix). Among them, active matrix liquid crystal displays change the arrangement of liquid crystal compounds by applying voltage, thereby changing the light emission intensity emitted by the backlight source to form an image. It is increasingly favored by people due to its high resolution, high contrast, low power, thin surface and light weight. Active matrix liquid crystal displays can be divided into two types according to active devices: MOS (metal oxide semiconductor) or other diodes on silicon chips as substrates; thin film transistors (Thin Film Transistor-TFT) on glass plates as substrates. Among them, the thin film transistor liquid crystal display (TFT-LCD) is the fastest growing at present. It has been well applied in display devices such as mobile phones, computers, LCD TVs and cameras, and has become the mainstream product in the current liquid crystal market. With the continuous development of TFT-LCD, wide viewing angle mode has become the goal pursued in the industry. The current mainstream wide viewing angle technologies mainly include VA vertical orientation technology, IPS in-plane switching technology and FFS edge field switching technology. These technologies require higher light transmittance and smaller color deviation. Negative liquid crystal compounds perform better in terms of color deviation and being affected by a vertical electric field. Compared with positive materials, they exhibit higher light transmittance and are therefore widely used.

[0006] With the widespread application of liquid crystal displays, the requirements for their performance are also constantly increasing. The high image quality of liquid crystal displays requires a wider operating temperature, faster response speed and higher contrast, while the power consumption is required to be lower and lower, which means that liquid crystal displays must have lower driving voltage and higher light transmittance. These performance improvements are inseparable from the improvement of liquid crystal materials. Summary of the invention

[0007] The purpose of the present invention is to provide a liquid crystal compound with a negative dielectric constant to improve the rotational viscosity and elastic coefficient characteristics of the liquid crystal material in the prior art, thereby increasing the response speed, light transmittance and contrast of the liquid crystal material and reducing the driving voltage.

[0008] Another object of the present invention is to provide a liquid crystal mixture comprising the above liquid crystal compound.

[0009] Another object of the present invention is to provide applications of the above liquid crystal compounds and liquid crystal mixtures.

[0010] Technical solution: In order to achieve the above object, according to one aspect of the present invention, a liquid crystal compound is provided, and the liquid crystal compound has a general formula I, which is:

[0011]

[0012] in

[0013] R is C1-C7 alkyl, C1-C7 alkoxy, C1-C7 alkenyl, C1-C7 alkenyloxy, cyclopentyl, or cyclopentyl substituted by C1-C7 alkyl, C1-C7 alkoxy, C1-C7 alkenyl or C1-C7 alkenyloxy;

[0014] n is 0, 1 or 2;

[0015] Selected from One or more of the group consisting of; when n is 1, One selected from the group consisting of the above groups; when n is 2, the general formula I includes two two are the same group or two different groups selected from the group consisting of the above groups.

[0016] According to another aspect of the present invention, a liquid crystal mixture having negative dielectric anisotropy is provided. The liquid crystal compound comprises at least one of the above liquid crystal compounds.

[0017] According to another aspect of the present invention, there is provided a use of the above-mentioned liquid crystal compound in a liquid crystal display material or a liquid crystal display device.

[0018] According to another aspect of the present invention, there is provided a use of the above-mentioned liquid crystal mixture in a liquid crystal display material or a liquid crystal display device.

[0019] Beneficial effects: The liquid crystal compound of the present invention can effectively improve the rotational viscosity and elastic coefficient characteristics of the liquid crystal material, thereby increasing the response speed, light transmittance and contrast of the liquid crystal display and reducing the driving voltage of the liquid crystal display. DETAILED DESCRIPTION

[0020] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0021] In a typical embodiment of the present invention, a liquid crystal compound is provided, wherein the liquid crystal compound has a general formula I, wherein the general formula I is

[0022]

[0023] In the general formula I

[0024] R is an alkyl, alkoxy, alkenyl or alkenyloxy group having 1 to 7 carbon atoms, or a cyclopentyl group, or a cyclopentyl group substituted with an alkyl, alkoxy, alkenyl or alkenyloxy group having 1 to 7 carbon atoms;

[0025] n is 0, 1 or 2;

[0026] When n is 1, Selected from Any of the groups consisting of;

[0027] When n is 2, in the general formula I Two occurrences, two Can be selected from The group consists of either the same group or two different groups.

[0028] The liquid crystal compound with negative dielectric constant of general formula I is white in pure state. The liquid crystal compound with negative dielectric constant is characterized by having a large dipole effect in the direction perpendicular to the long axis of the molecule, so the corresponding dielectric constant has a relatively large component in the vertical direction, that is, it has a high vertical dielectric constant ε ⊥ , so the dielectric anisotropy △ε=ε / / -ε ⊥ It is negative. Due to its high vertical dielectric constant ε ⊥ , liquid crystal molecules tend to be distributed in a direction perpendicular to the electric field, thus showing a lower pre-tilt angle, and negative liquid crystal materials are arranged on a horizontal plane under an edge electric field, and the pre-tilt angle distribution is more uniform than that of positive materials, thus showing higher light transmittance and wide viewing angle, and are particularly suitable for preparing VA, PSVA and FFS type liquid crystal materials with high transmittance and wide viewing angle; in addition, the addition of liquid crystal compounds with negative dielectric constants can increase the bending elastic coefficient K of the system 33 , thereby improving the light penetration and contrast in the entire system, which is beneficial to energy saving, and can improve the image display quality to better meet the performance requirements of liquid crystal displays.

[0029] Another outstanding feature of the liquid crystal compound with negative dielectric constant of general formula I is that when combined with other types of liquid crystal compounds, suitable optical properties and dielectric constants can be obtained by adding a relatively small amount. Therefore, the overall viscosity of the liquid crystal mixture obtained by combining the liquid crystal compound with negative dielectric constant of general formula I with other types of liquid crystal compounds is relatively low, and the reduced viscosity can effectively reduce the response time of the liquid crystal material and increase the response speed.

[0030] In addition, it should be clear to those skilled in the art that the above-mentioned alkyl group includes not only straight-chain alkyl groups but also corresponding branched-chain alkyl groups.

[0031] In order to obtain a more suitable liquid crystal width, a higher dielectric anisotropy value, a smaller rotational viscosity and a suitable elastic coefficient K, which is more conducive to improving the response speed of the liquid crystal material, reducing the threshold voltage, and improving the mutual solubility of the liquid crystal material, in a preferred embodiment of the present application, the liquid crystal compound with a negative dielectric constant of the above-mentioned general formula I is a negative polarity liquid crystal compound having formulas I1 to I13.

[0032] The above compounds having general formulae I1 to I13 are as follows:

[0033]

[0034]

[0035] Wherein, R1 is an alkyl, alkoxy, alkenyl or alkenyloxy group having 1 to 7 carbon atoms, or a cyclopentyl group, or a cyclopentyl group substituted by an alkyl, alkoxy, alkenyl or alkenyloxy group having 1 to 7 carbon atoms.

[0036] Since the liquid crystal compound with a negative dielectric constant of the general formula I of the present invention has a lower rotational viscosity and a higher elastic coefficient K, when the liquid crystal compound with the general formula I is combined with other types of liquid crystal compounds to form a liquid crystal mixture with a negative dielectric constant, the characteristics of the liquid crystal mixture with a negative dielectric constant can be adjusted in a wider range, thereby meeting the performance requirements of more liquid crystal materials; and, the liquid crystal compound with a negative dielectric constant of the general formula I of the present invention has good mutual solubility when mixed with other types of liquid crystal compounds, and has fewer restrictions on the types of other liquid crystal compounds used in combination, and can be applied to various liquid crystal mixtures corresponding to the purpose, which is particularly beneficial to improving the comprehensive properties of the liquid crystal mixture; in addition, the liquid crystal mixture has good UV, light and thermal stability.

[0037] The liquid crystal mixture with a negative dielectric constant of the present invention can be prepared according to conventional methods. Usually, the required amount of components is dissolved in the components constituting the main component in a relatively low amount at high temperature; the solutions of the components can also be mixed into an organic solvent, such as acetone, chloroform or methanol, and the solvent is removed again after sufficient mixing, such as by distillation.

[0038] The types of existing liquid crystal compounds contained in the liquid crystal mixture with a negative dielectric constant of the present invention are not limited. Any type of liquid crystal compound can be selected according to the purpose to form a liquid crystal mixture together with the liquid crystal compound of the present invention, and other additives in the relevant technical field can be added as needed. For example, a polymerizable compound and / or a stabilizer with a mass content of 0 to 20% can be added.

[0039] The general formula of the above polymerizable compound is as follows:

[0040]

[0041] in

[0042] —T1 and —T2 each independently represent or epoxy;

[0043] —Y1— and —Y2— each independently represent a single bond or an alkyl group having 1 to 8 carbon atoms;

[0044] —X1— and —X2— each independently represent a single bond, —O—, —CO—, —COO— or —OCO—;

[0045] m is 0, 1 or 2;

[0046] When m is 1, —Z1— represents a single bond, —O—, —CO—, —COO—, —OCO—, —CH2O—, —OCH2—, —C2H4—, —CF2O—, —OCF2—, —C≡C—, —CH=CH—,

[0047] When m is 2, -Z1- appears twice in the general formula, and each occurrence of -Z1- independently represents a single bond, -O-, -CO-, -COO-, -OCO-, -CH2O-, -OCH2-, -C2H4-, -CF2O-, -OCF2-, -C≡C-, -CH=CH-,

[0048] express The -CH2- on the cyclohexyl group can be replaced by O, or it can represent The =CH- on the benzene ring can be replaced by N, and the H on the benzene ring can be replaced by F, or it can be expressed as

[0049] When m is 1, express The -CH2- on the cyclohexyl group can be replaced by O, or it can represent The =CH- on the benzene ring can be replaced by N, and the H on the benzene ring can be replaced by F, or it can be expressed as

[0050] When m is 2, the general formula includes two Right now appears twice in the general formula, Each time it occurs, it is independently The -CH2- on the cyclohexyl group can be replaced by O, or The =CH- on the benzene ring can be replaced by N, the H on the benzene ring can be replaced by F, or

[0051] The stabilizer is preferably one or more compounds represented by general formulae IV1 to IV5.

[0052]

[0053] In formula IV1 to IV5

[0054] R7 is a halogenated or unsubstituted alkyl, alkoxy or alkenyl group having 1 to 7 carbon atoms, wherein the alkyl, alkoxy or alkenyl group is a straight chain or branched chain alkyl, alkoxy or alkenyl group;

[0055] for Any of the groups consisting of.

[0056] In a preferred embodiment of the present application, the liquid crystal mixture further comprises at least one polar compound and / or at least one non-polar compound. The polar compound is preferably a negative polarity compound, and the negative polarity compound is preferably one or more compounds selected from formula II1 to II77, and formula II1 to II77 are respectively:

[0057]

[0058]

[0059]

[0060]

[0061] Wherein, R3 and R4 each independently represent H, an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms or an alkenyloxy group having 2 to 7 carbon atoms, and H or CH2 in the above alkyl, alkoxy, alkenyl and alkenyloxy groups may be substituted by cyclopentyl; R3 and R4 may also be cyclopentyl or a cyclopentyl group substituted by an alkyl group, alkoxy group or alkenyl group having 1 to 7 carbon atoms; the alkyl group having 1 to 7 carbon atoms is: -CH3, -C2H5, -C3H7, -C4H9, -C5H 11 、-C6H 13 or -C7H 15 ; Alkenyl having 1 to 7 carbon atoms is preferably -CH=CH2, -CH=CHCH3, -CH=CHC2H5, -CH=CHC3H7, -C2H4CH=CH2, -C2H4CH=CHCH3, -C3H6CH=CH2 or -C3H6CH=CHCH3; Alkoxy having 1 to 7 carbon atoms is preferably -OCH3, -OC2H5, -OC3H7, -OC4H9, -OC5H 11 、-OC6H 13or -OC7H 15 ; The alkoxy group having 1 to 7 carbon atoms is preferably -OCH2CH=CH2, -OCH2CH=CHCH3 or -OCH2CH=CHC2H5.

[0062] The above-mentioned polar liquid crystal compounds II1~II77 have negative dielectric anisotropy and can be combined with the compounds represented by general formula I to form a negative dielectric liquid crystal mixture, which can be used to adjust the system's parameters such as the dielectric constant, refractive index, rotational viscosity γ1, elastic modulus and clearing point temperature. The combination with general formula I is beneficial to improving the low-temperature reliability of the liquid crystal mixture, reducing the lower limit temperature of the liquid crystal medium, and broadening the operating temperature range of the liquid crystal medium.

[0063] The non-polar liquid crystal compound is selected from one or more compounds represented by formula III1 to III29; wherein formula III1 to III29 are as follows:

[0064]

[0065]

[0066] In formula III1 to III29, R5 and R6 are alkyl groups having 1 to 7 carbon atoms, alkoxy groups having 1 to 7 carbon atoms, alkenyl groups having 2 to 7 carbon atoms or alkenyloxy groups having 2 to 7 carbon atoms, and H or CH2 in the above alkyl groups, alkoxy groups, alkenyl groups and alkenyloxy groups may be substituted by cyclopentyl groups; R5 and R6 may also be cyclopentyl groups or cyclopentyl groups substituted by alkyl groups, alkoxy groups or alkenyl groups having 1 to 7 carbon atoms; the above alkyl groups having 1 to 7 carbon atoms are -CH3, -C2H5, -C3H7, -C4H9, -C5H 11 、-C6H 13 or -C7H 15 The alkenyl group having 2 to 7 carbon atoms is preferably -CH=CH2, -CH=CHCH3, -CH=CHC2H5, -CH=CHC3H7, -C2H4CH=CH2, -C2H4CH=CHCH3, -C3H6CH=CH2 or -C3H6CH=CHCH3; the alkoxy group having 1 to 7 carbon atoms is preferably -OCH3, -OC2H5, -OC3H7, -OC4H9, -OC5H 11 、-OC6H 13 or -OC7H 15The alkenyloxy group having 2 to 7 carbon atoms is preferably -OCH2CH=CH2, -OCH2CH=CHCH3 or -OCH2CH=CHC2H5. It should be clear to those skilled in the art that the alkyl, alkoxy, alkenyl and alkenyloxy groups can be straight-chain alkyl, straight-chain alkoxy, straight-chain alkenyl and straight-chain alkenyloxy groups, or branched alkyl, alkoxy, alkenyl and alkenyloxy groups.

[0067] The above-mentioned non-polar liquid crystal compounds III1 to III20 have a relatively low rotational viscosity γ1, and their response time is proportional to the rotational viscosity γ1, which means that the lower the rotational viscosity γ1 value, the lower the response time, and the faster the response speed. The liquid crystal mixture containing the above-mentioned non-polar liquid crystal compounds III1 to III20 can be used to manufacture a fast-response liquid crystal medium. The above-mentioned non-polar liquid crystal compounds III21 to III27 have a terphenyl structure, which is beneficial to increase the optical anisotropy △n value of the system. Usually, the value of the optical path difference d·△n is predetermined, then the higher the △n value, the lower the d value, and the response speed is inversely proportional to the d value, so that the response speed of the liquid crystal mixture containing the above-mentioned non-polar liquid crystal compounds III21 to III27 has a more ideal value. The above-mentioned non-polar liquid crystal compounds III28 to III29 have a relatively high clearing point temperature, which is mainly used to adjust the T of the system. NI value, so that the liquid crystal mixture having the above-mentioned non-polar liquid crystal compounds III28 to III29 is beneficial to increasing the upper limit temperature of the use of the liquid crystal medium and widening the operating temperature range of the liquid crystal medium.

[0068] The outstanding feature of the liquid crystal compound represented by general formula I in the present invention is that when combined with a low-viscosity liquid crystal compound, suitable optical properties can be obtained by adding a small amount, so the overall viscosity of the liquid crystal mixture can be reduced and the response speed can be increased. It is preferred that at least one low-viscosity non-polar liquid crystal compound with a structural formula of III1 to III20 is added to the liquid crystal mixture to obtain a low-viscosity liquid crystal mixture and improve the response speed. It is particularly preferred that at least one low-viscosity non-polar liquid crystal compound with a structural formula of III5 is added to the liquid crystal mixture. The liquid crystal mixture is preferably used in vertical alignment display (VA), polymer stabilized vertical alignment (PSVA) or fringe field switching (FFS) type liquid crystal display mode.

[0069] The content of the liquid crystal compound in the above-mentioned liquid crystal mixture can be adjusted according to the performance requirements of the liquid crystal material. In order to obtain a more suitable liquid crystal width, a higher dielectric anisotropy value, a smaller rotational viscosity and a suitable elastic coefficient K, it is more conducive to improving the response speed of the liquid crystal material, reducing the threshold voltage, and improving the mutual solubility of the liquid crystal material. In a preferred embodiment of the present invention, the weight content of the liquid crystal compound having the general formula I in the above-mentioned liquid crystal mixture is 0.1 to 75%, preferably 1 to 50%, and further preferably 1 to 30%. The remaining ingredients can be added according to the above-mentioned teachings of the present invention. In short, the sum of the percentage content of each component is 100%.

[0070] In a typical embodiment of the present application, there is provided an application of the liquid crystal compound represented by the above general formula I in a liquid crystal display device. In another typical embodiment of the present application, there is provided an application of a liquid crystal mixture comprising the liquid crystal compound represented by the general formula I in a liquid crystal display device. The application of the liquid crystal compound of the present invention in the preparation of a liquid crystal display material or a liquid crystal display device can significantly improve the performance of the liquid crystal display material or the liquid crystal display device.

[0071] The beneficial effects of the present invention will be further illustrated below in combination with embodiments and comparative examples.

[0072] The following examples are intended to illustrate the present invention but are not intended to limit it. The percentages in the examples are all by mass and the temperatures are expressed in degrees Celsius. The measured physicochemical parameters are expressed as follows: NI represents the clearing point; △n represents the optical anisotropy (△n=n e -n o , 589nm, measurement temperature 25℃); ε ⊥ represents the perpendicular dielectric constant (measured at 25°C); △ε represents the dielectric anisotropy (△ε=ε ∥ -ε ⊥ , 25℃); k 33 represents the bending elastic coefficient (measured at 25°C); γ1 represents the rotational viscosity (measured at 25°C), and T is measured by DSC. NI ; △n was measured by Abbe refractometer; ε was measured by CV ⊥ , ∆ε, k 33 and γ1.

[0073] In various embodiments of the present invention, the general structural formula of each compound in the liquid crystal mixture is:

[0074]

[0075] wherein a, b, c, d, e, f, g and h are each independently selected from 0, 1, 2, 3 or 4.

[0076] Name of the main chain of liquid crystal molecules: cyclohexyl Represented by the initial letter C; benzene ring Represented by the initial letter P; cyclohexenyl Represented by A; difluorobenzene Expressed as PFF; Tetrahydropyran It is represented by Py; -CH2O- is represented by -CH2O-.

[0077] In addition, liquid crystal compounds It is expressed as 3HHV; It is represented by VHHP1; Indicated by CC31D1.

[0078] The corresponding codes for the specific group structures are shown in Table 1.

[0079] Table 1

[0080]

[0081]

[0082] Referring to the general structural formula of each compound in the above liquid crystal mixture, each compound branch chain is converted into a chemical formula according to Table 2 below, wherein the group C n H 2n+1 and C m H 2m+1 are straight chain alkyl radicals having n and m carbon atoms, respectively, C p Cyclopentyl C n H 2n+1 C p It means a cyclopentyl group with a straight-chain alkyl group of n carbon atoms. The main chain is in front and the side chain is in the back, such as With C-(CH2O)-PFF3H, Expressed as CC-CH2O-PFF3H, Expressed as PPFFCpO2, Expressed as CC-CH2O-PFF3O2, Expressed as PPFP2Cp.

[0083] Table 2

[0084]

[0085]

[0086] Example 1

[0087] The synthesis method of CC-CH2O-PFF3H is as follows:

[0088]

[0089] 1) Preparation of sulfonic acid ester of propyl dicyclohexyl carbinol

[0090] Install a thermometer, mechanical stirring and constant pressure dropping funnel in a 2000ml four-necked bottle, pass nitrogen, add 75g of propyldicyclohexylmethanol, 101.6g of triethylamine and 600ml of dichloromethane to the reaction system, stir and cool with an ice-salt bath, add a mixed solution of 115g of toluenesulfonyl chloride / 200ml of dichloromethane dropwise to the reaction system at 0-10°C, continue stirring and react at 0-10°C for 1h, then take samples for analysis, after the reaction is completed, pour the system into water, dilute with dichloromethane, let stand to separate, separate the lower organic phase, wash with water to neutrality, dry with anhydrous magnesium sulfate, remove the solvent, and crystallize with ethanol to obtain a product with a content of more than 99.5%.

[0091] 2) Preparation of CC-CH2O-PFF3H

[0092] A low-temperature thermometer, mechanical stirring and constant pressure dropping funnel were installed in a 250ml three-necked flask, nitrogen was passed through, 10g 2,3-difluorophenol, 13.8g anhydrous potassium carbonate and 50ml DMF were added to the system, stirred and dissolved, and the mixed solution of propyl dicyclohexyl methanol sulfonate and DMF obtained in step 1) was added dropwise to the reaction system at 65°C, and after the dropwise addition, the mixture was kept at 80°C for 4h before post-treatment, poured into a separating funnel, tap water was added thereto, allowed to stand for stratification, washed with water until neutral, concentrated to remove the solvent, and then recrystallized with ethanol to obtain 9.8g trans-CC-CH2O-PFF3H with a purity of more than 99.8%. The composition and measurement parameters of the liquid crystal mixture of Example 1 are shown in Table 3.

[0093] Table 3

[0094]

[0095] Note: The liquid crystal compound with serial number 5 is a liquid crystal compound having the general formula I.

[0096] Example 2

[0097] The composition and measurement parameters of the liquid crystal mixture of Example 2 are shown in Table 4.

[0098] Table 4

[0099]

[0100]

[0101] Note: 7 is a liquid crystal compound having the general formula I.

[0102] Example 3

[0103] The composition and measurement parameters of the liquid crystal mixture of Example 3 are shown in Table 5.

[0104] Table 5

[0105]

[0106] Note: 7 is a liquid crystal compound having the general formula I.

[0107] Example 4

[0108] The composition and measurement parameters of the liquid crystal mixture of Example 4 are shown in Table 6.

[0109] Table 6

[0110]

[0111]

[0112] Note: 7 is a liquid crystal compound having the general formula I.

[0113] Example 5

[0114] The composition and measurement parameters of the liquid crystal mixture of Example 5 are shown in Table 7.

[0115] Table 7

[0116]

[0117] Note: 7 is a liquid crystal compound having the general formula I.

[0118] Example 6

[0119] The composition and measurement parameters of the liquid crystal mixture of Example 6 are shown in Table 8.

[0120] Table 8

[0121]

[0122] Note: 5 is a liquid crystal compound having the general formula I.

[0123] Example 7

[0124] The composition and measurement parameters of the liquid crystal mixture of Example 7 are shown in Table 9.

[0125] Table 9

[0126]

[0127]

[0128] Note: 7 is a liquid crystal compound having the general formula I.

[0129] Example 8

[0130] The synthesis method of C-CH2O-PFF3H is as follows:

[0131]

[0132] 1) Preparation of propylcyclohexylmethoxy sulfonic acid ester

[0133] Install a thermometer, mechanical stirring and constant pressure dropping funnel in a 1000ml four-necked bottle, pass nitrogen, add 78g of propylcyclohexylmethanol, 101.2g of triethylamine and 400ml of dichloromethane to the reaction system, stir and cool with an ice-salt bath, add a mixed solution of 114g of methylbenzenesulfonyl chloride / 200ml of dichloromethane dropwise to the reaction system at 0-10°C, continue stirring and react at 0-10°C for 1h, then take samples for analysis, after the reaction is completed, pour the system into water, dilute with dichloromethane, let stand to separate, separate the lower organic phase, wash with water to neutrality, dry with anhydrous magnesium sulfate, remove the solvent, and crystallize with ethanol to obtain a product with a content of more than 99.5%.

[0134] 2) Preparation of C-CH2O-PFF3H

[0135] A low-temperature thermometer, a mechanical stirrer and a constant-pressure dropping funnel were installed in a 250 ml three-necked flask, and nitrogen was passed through. 10 g of 2,3-difluorophenol, 13.8 g of anhydrous potassium carbonate and 50 ml of DMF were added to the system. After stirring and dissolving, a mixed solution of propylcyclohexylmethoxy sulfonate and DMF obtained in step 1) was added dropwise to the reaction system at 65° C. After the addition was completed, the mixture was kept at 80° C. for 4 h and then post-treated. After pouring into a separating funnel, tap water was added thereto, the mixture was allowed to stand for stratification, washed with water until neutral, concentrated to remove the solvent, and then recrystallized from ethanol to obtain 10 g of trans-C-CH2O-PFF3H with a purity of more than 99.9%.

[0136] The composition and measurement parameters of the liquid crystal mixture of Example 8 are shown in Table 10.

[0137] Table 10

[0138]

[0139]

[0140] Note: 7 is a liquid crystal compound having the general formula I.

[0141] Example 9

[0142] The composition and measurement parameters of the liquid crystal mixture of Example 9 are shown in Table 11.

[0143] Table 11

[0144]

[0145]

[0146] Note: 7 is a liquid crystal compound having the general formula I.

[0147] Example 10

[0148] The composition and measurement parameters of the liquid crystal mixture of Example 10 are shown in Table 12.

[0149] Table 12

[0150]

[0151] Note: 7 is a liquid crystal compound having the general formula I.

[0152] Embodiment 11

[0153] The composition and measurement parameters of the liquid crystal mixture of Example 11 are shown in Table 13.

[0154] Table 13

[0155]

[0156]

[0157] Note: 8 is a liquid crystal compound having the general formula I.

[0158] Example 12

[0159] The composition and measurement parameters of the liquid crystal mixture of Example 12 are shown in Table 14.

[0160] Table 14

[0161]

[0162] Note: 8 is a liquid crystal compound having the general formula I.

[0163] Example 13

[0164] The liquid crystal mixture composition and measurement parameters of Example 13 are shown in Table 15.

[0165] Table 15

[0166]

[0167] Note: 7 is a liquid crystal compound having the general formula I.

[0168] Embodiment 14

[0169] The liquid crystal mixture composition and measurement parameters of Example 14 are shown in Table 16.

[0170] Table 16

[0171]

[0172]

[0173] Note: 7 is a liquid crystal compound having the general formula I.

[0174] Embodiment 15

[0175] The liquid crystal mixture composition and measurement parameters of Example 15 are shown in Table 17.

[0176] Table 17

[0177]

[0178] Note: 6 is a liquid crystal compound having the general formula I.

[0179] Comparative Example 1

[0180] The liquid crystal mixture composition and measurement parameters of Comparative Example 1 are shown in Table 18.

[0181] Table 18

[0182]

[0183]

[0184] Comparative Example 2

[0185] The liquid crystal mixture composition and measurement parameters of Comparative Example 2 are shown in Table 19.

[0186] Table 19

[0187]

[0188] Among them, in Comparative Example 1 and Comparative Example 2, the liquid crystal compound (CC-CH2O-PFF3O2) replaced the (CC-CH2O-PFF3H).

[0189] From the above examples, it can be found that the liquid crystal compound having the general formula I can reduce the viscosity of the system and increase the bending elastic coefficient K of the system. 33 and the perpendicular dielectric constant ε ⊥, thereby improving the response speed, improving the light penetration rate in the entire system, being beneficial to energy saving, and being beneficial to improving the contrast. When the liquid crystal compound of the general formula I is mixed with other liquid crystal compounds of different types, a liquid crystal mixture with high-definition bright spots, low viscosity and high elastic coefficient can be obtained, especially when mixed with a non-polar liquid crystal compound having the general formula III5 (such as a non-polar liquid crystal compound with the code 3HHV), a low-viscosity liquid crystal mixture can be obtained, which can be used to manufacture a fast-responding liquid crystal medium. The above-mentioned measurement parameters are related to the physicochemical properties of all liquid crystal compounds constituting the liquid crystal medium. The liquid crystal mixture of the present invention is mainly used to adjust the liquid crystal parameters of the system.

[0190] By comparing Example 14 with Comparative Example 1 and Example 15 with Comparative Example 2, it can be clearly found that when the liquid crystal mixture contains a liquid crystal compound having the general formula I, it has a relatively low rotational viscosity, which is particularly beneficial for manufacturing a fast-responding liquid crystal medium and is beneficial for adjusting a suitable clearing point T of the system. NI , bending elastic coefficient K 33 , vertical dielectric constant ε ⊥ and dielectric anisotropy Δε value, which are helpful for obtaining a wider operating temperature, faster response speed, higher contrast and transmittance, and lower power consumption.

[0191] Although the present invention does not exhaust all liquid crystal mixtures claimed for protection, it is foreseeable that, based on the above disclosed embodiments, other similar compounds can be obtained by similar reaction routes by combining their own professional attempts without creative work. Due to limited space, only representative implementations are listed here.

[0192] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A liquid crystal mixture, characterized in that: The liquid crystal mixture consists of 5.5% by mass Liquid crystal compounds with structures; The mass fraction is 5.0% Liquid crystal compounds with structures; The mass fraction is 8.0% Liquid crystal compounds with structures; The mass fraction is 11.0% Liquid crystal compounds with structures; The mass fraction is 3.7% Liquid crystal compounds with structures; The mass fraction is 7.4% Liquid crystal compounds with structures; The mass fraction is 7.4% Liquid crystal compounds with structures; The mass fraction is 2.5% Liquid crystal compounds with structures; The mass fraction is 30.3% Liquid crystal compounds with structures; The mass fraction is 5.1% Liquid crystal compounds with structures; The mass fraction is 4.0% Liquid crystal compounds with structures; The mass fraction is 6.1% The liquid crystal compound with structure and 4.0% by mass The structure is composed of liquid crystal compounds.

2. Use of the liquid crystal mixture according to claim 1 in a negative display mode, wherein the negative display mode is VA, PSVA or FFS display mode.

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