1. A negative dielectric anisotropy liquid crystal composition, comprising:

at least one compound represented by formula I; and the number of the first and second groups,

at least one compound represented by formula II;

wherein, in the formula I, R₁、R₂Each independently represents an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkenyloxy group having 2 to 5 carbon atoms; and, R₁、R₂Each independently of the other, H on any carbon atom in (a) is optionally substituted with F;

Z₁、Z₂each independently represents-CH₂O-、-CH₂S-、-OCH₂-、-SCH₂-、-CH＝CH-CH₂O-、-CH＝CH-CH₂S-、-OCH₂-CH＝CH、-SCH₂-CH＝CH、-CF₂O-、-OCF₂-、-CH＝CH-CF₂O-, or, -OCF₂-CH ═ CH, where any or all H are optionally substituted with F;

each independently selected from the group consisting of:

x represents O or S;

in the formula II, the reaction mixture is shown in the specification,

R₃、R₄each independently represents an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkenyloxy group having 2 to 5 carbon atoms; and, R₃、R₄Each independently of the other, H on any carbon atom in (a) is optionally substituted with F;

each independently selected from the followingGroup (iii):

p represents 0, 1 or 2.

2. The negative dielectric anisotropy liquid crystal composition of claim 1, wherein the compound of formula I is selected from the group consisting of compounds of formulae I1 to I82:

R₁、R₂each independently represents an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkenyloxy group having 2 to 5 carbon atoms; r₁、R₂Each independently of the other, is optionally substituted with F.

3. The liquid crystal composition of claim 1 or 2, wherein the compound represented by formula ii is selected from the group consisting of compounds represented by formulae ii-1 to ii-10 below:

R₃、R₄each independently represents an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkenyloxy group having 2 to 5 carbon atoms; r₃、R₄Each hydrogen on any carbon atom in (a) is independently optionally substituted with fluorine;

(F) represents F or H.

4. The negative dielectric anisotropy liquid crystal composition according to any one of claims 1 to 3, further comprising one or more compounds represented by the following formula III:

R₅、R₆each independently represents an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkenyloxy group having 2 to 5 carbon atoms; and, R₅、R₆Each independently of the other, H on any carbon atom in (a) is optionally substituted with F;

Z₃represents a single bond or-CH₂O-；

q and r each independently represent 0, 1 or 2;

each independently selected from the group consisting of:

5. the negative dielectric anisotropic composition of claim 4, wherein the compound represented by formula iii is selected from the group consisting of compounds represented by formulae iii-1 to iii-17 below:

R₅、R₆each independently represents an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkenyloxy group having 2 to 5 carbon atoms, and R₅、R₆Each H on any carbon atom in the group is independentlyOptionally substituted with F.

6. The negative dielectric anisotropy liquid crystal composition according to any one of claims 1 to 5, further comprising one or more compounds represented by the following formulae IV-1 to IV-8:

。

7. the negative dielectric anisotropic liquid crystal composition according to claim 4 or 5, wherein the amount of the compound represented by formula I is 1 to 50 parts by mass, the amount of the compound represented by formula II is 1 to 60 parts by mass, and the amount of the compound represented by formula III is 1 to 50 parts by mass, based on 100 parts by mass of the negative dielectric anisotropic liquid crystal composition.

8. The negative dielectric anisotropic liquid crystal composition of claim 6, wherein the amount of the compound represented by formula I is 1 to 50 parts by mass, the amount of the compound represented by formula II is 1 to 60 parts by mass, the amount of the compound represented by formula III is 1 to 50 parts by mass, and the amount of the compound represented by formula IV is 0.01 to 1.00 part by mass, based on 100 parts by mass of the negative dielectric anisotropic liquid crystal composition.

9. A liquid crystal display device, wherein the liquid crystal composition comprises the liquid crystal composition according to any one of claims 1 to 8; the liquid crystal display device is an active matrix display device or a passive matrix display device.

Background

With the development of technology and the progress of the times, the field of application of liquid crystal mixtures is gradually extended to displays for portable computers and desktop computers, navigation systems and video applications. These fields of application place increasingly higher demands on the properties of the liquid-crystal mixtures.

The spatial arrangement of molecules in liquid crystals has an important influence on liquid crystal displays. Wherein the dielectric constant epsilon of the liquid crystal medium differs in value with respect to the direction parallel to the capacitor and in value with respect to the direction perpendicular to the capacitor. The case where the longitudinal axis of the molecule is oriented perpendicularly to the capacitor plates with a greater dielectric constant than in the parallel orientation is called dielectrically positive. In other words, the dielectric constant ε if parallel to the longitudinal axis of the molecule_||Greater than the dielectric constant ε perpendicular to the longitudinal axis of the molecule_⊥Then the dielectric anisotropy Deltaε_||-ε_⊥Greater than 0. Most liquid crystal media used in conventional displays are dielectrically positive media. Relatively low, Δ ε ═ ε_||-ε_⊥Liquid-crystalline media smaller than 0 are referred to as liquid-crystalline media of negative dielectric anisotropy.

With the development of technology, it was found that, for example, in the display mode of VA-TFTs ("vertical alignment"), an improvement in the viewing angle dependence can be obtained by negatively adopting a liquid-crystalline medium of negative dielectric anisotropy. Thus, liquid crystal media of negative dielectric anisotropy are widely studied, and for such liquid crystal media, it is desired to have a fast response time and little afterimage. However, the increase in the fast response time tends to increase the afterimage of the liquid crystal medium, especially after light exposure, thereby affecting the stability thereof. Therefore, how to realize a negative dielectric anisotropic liquid crystal composition having a fast response time and improved stability by improving the afterimage defect after light exposure is one of the problems to be solved in the art.

Disclosure of Invention

For liquid crystal medium, the response time of the liquid crystal medium is G1/K according to different display modes₁₁Or G1/K₃₃And (4) correlating. Response time of liquid crystal medium and G1/K in VA (vertical alignment) or PS-VA (Polymer stabilized vertical alignment) mode₃₃Related to the related art, but In FFS (Fringe Field Switching), IPS (In-Plane Switching), PS-FFS (Polymer stabilized Fringe Field Switching), Polymer stabilizationFringe field Switching), PS-IPS (Polymer stabilized In-Plane Switching), etc., the response time of the liquid crystal medium and G1/K₁₁And (4) correlating.

As a result of intensive studies, the inventors of the present invention have found that a reduction in G1/K can be achieved while maintaining an appropriate optical anisotropy value and dielectric anisotropy by using a negative dielectric anisotropy liquid crystal composition containing a combination of a compound represented by formula I and a compound represented by formula II₁₁Or G1/K₃₃The value thus has a fast response time and an increased VHR after irradiation with UV light, thereby avoiding/reducing the occurrence of display afterimage phenomena, enabling to obtain display advantages of reduced power consumption and improved stability.

The invention comprises the following technical scheme.

In one aspect, the present invention provides a negative dielectric anisotropic liquid crystal composition comprising:

at least one compound represented by formula I; and the number of the first and second groups,

at least one compound represented by formula II;

wherein, in the formula I, R₁、R₂Each independently represents an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkenyloxy group having 2 to 5 carbon atoms; and, R₁、R₂Each independently of the other, H on any carbon atom in (a) is optionally substituted with F;

Z₁、Z₂each independently represents-CH₂O-、-CH₂S-、-OCH₂-、-SCH₂-、-CH＝CH-CH₂O-、-CH＝CH-CH₂S-、-OCH₂-CH＝CH、-SCH₂-CH＝CH、-CF₂O-、-OCF₂-、-CH＝CH-CF₂O-, or, -OCF2-CH ═ CH, wherein any or all H are optionally substituted with F;

each independently selected from the group consisting of:

x represents O or S;

in the formula II, the reaction mixture is shown in the specification,

R₃、R₄each independently represents an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkenyloxy group having 2 to 5 carbon atoms; and, R₃、R₄Each independently of the other, H on any carbon atom in (a) is optionally substituted with F;

each independently selected from the group consisting of:

p represents 0, 1 or 2.

In another aspect, the present invention provides a liquid crystal display device comprising the negative dielectric anisotropic liquid crystal composition of the present invention; the liquid crystal display device is an active matrix display device or a passive matrix display device.

Effects of the invention

Compared with the prior art, the negative dielectric anisotropy liquid crystal composition can reduce G1/K on the basis of maintaining proper optical anisotropy value and dielectric anisotropy₁₁Or G1/K₃₃Thereby having a fast response time and after irradiation with UV lightThe display device has an improved VHR, thereby avoiding/reducing the occurrence of the afterimage phenomenon of the display, and can obtain the display advantages of reduced power consumption and improved stability.

Detailed Description

[ liquid Crystal composition ]

The negative dielectric anisotropic liquid crystal composition of the present invention comprises:

at least one compound represented by formula I; and the number of the first and second groups,

at least one compound represented by formula II;

wherein, in the formula I, R₁、R₂Each independently represents an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkenyloxy group having 2 to 5 carbon atoms; and, R₁、R₂Each independently of the other, H on any carbon atom in (a) is optionally substituted with F;

Z₁、Z₂each independently represents-CH₂O-、-CH₂S-、-OCH₂-、-SCH₂-、-CH＝CH-CH₂O-、-CH＝CH-CH₂S-、-OCH₂-CH＝CH、-SCH₂-CH＝CH、-CF₂O-、-OCF₂-、-CH＝CH-CF₂O-, or, -OCF₂-CH ═ CH, where any or all H are optionally substituted with F;

each independently selected from the group consisting of:

x represents O or S;

in the formula II, the reaction mixture is shown in the specification,

R₃、R₄each independently represents the number of carbon atoms1 to 5 alkyl groups, 1 to 5 alkoxy groups, 2 to 5 alkenyl groups, or 2 to 5 alkenyloxy groups; and, R₃、R₄Each independently of the other, H on any carbon atom in (a) is optionally substituted with F;

each independently selected from the group consisting of:

p represents 0, 1 or 2.

Preferably, the compound represented by the formula I is selected from the group consisting of compounds represented by the following formulae I1 to I82, wherein the substituent R₁、R₂The definitions of (a) are the same as those described above.

As the aforementioned R₁、R₂The "alkyl group having 1 to 5 carbon atoms" independently of each other may be a straight-chain alkyl group, a branched-chain alkyl group, or a cyclic alkyl group, and is preferably a straight-chain alkyl group. Examples of such a straight-chain alkyl group include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, and an n-pentyl group. More preferably methyl, ethyl or propyl.

As the aforementioned R₁、R₂Examples of the "alkoxy group having 1 to 5 carbon atoms" which are independently represented include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, n-pentoxy group, and tert-pentoxy group. Further preferred is a methoxy group, an ethoxy group or a n-propoxy group.

As the aforementioned R₁、R₂Examples of the "alkenyl group having 2 to 5 carbon atoms" which are independently represented include an ethenyl group, a propenyl group, a butenyl group, a 2-methylpropenyl group, a 1-pentenyl group, a 2-methyl-1-butenyl group, a 3-methyl-1-butenyl group, and a 2-methyl-2-butenyl group. Further preferred is an ethylene group or a propylene group.

As the aforementioned R₁、R₂Examples of the "alkenyloxy group having 2 to 5 carbon atoms" which are independently represented include an vinyloxy group, a propenyloxy group, a butenyloxy group, a 2-methylpropenyloxy group, a 1-pentenyloxy group, a 2-methyl-1-butenyloxy group, a 3-methyl-1-butenyloxy group, and a 2-methyl-2-butenyloxy group. Further preferred is an ethyleneoxy group or a propyleneoxy group.

In the negative dielectric anisotropic liquid crystal composition of the present invention, the compound represented by the above formula II is preferably selected from the group consisting of the compounds represented by the following formulae II-1 to II-10. Wherein R is₃、R₄The definitions of (a) are the same as those described above.

(F) Represents F or H.

As the aforementioned R₃、R₄The "alkyl group having 1 to 5 carbon atoms" independently of each other may be a straight-chain alkyl group, a branched-chain alkyl group, or a cyclic alkyl group, and is preferably a straight-chain alkyl group. Examples of such a straight-chain alkyl group include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, and an n-pentyl group.

As the aforementioned R₃、R₄Examples of the "alkoxy group having 1 to 5 carbon atoms" which are independently represented include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, n-pentoxy group, and tert-pentoxy group. Further preferred is a methoxy group, an ethoxy group or a n-propoxy group.

As the aforementioned R₃、R₄Examples of the "alkenyl group having 2 to 5 carbon atoms" which are independently represented include an ethenyl group, a propenyl group, a butenyl group, a 2-methylpropenyl group, a 1-pentenyl group, a 2-methyl-1-butenyl group, a 3-methyl-1-butenyl group, and a 2-methyl-2-butenyl group. Further preferred is an ethylene group or a propylene group.

As the aforementioned R₃、R₄Examples of the "alkenyloxy group having 2 to 5 carbon atoms" independently of each other include an vinyloxy group, a propenyloxy group, a butenyloxy group, a 2-methylpropenyloxy group, a 1-pentenyloxy group, a 2-methyl-1-butenyloxy group, a 3-methyl-1-butenyloxy group, and a 2-methyl-1-butenyloxy group-2-butenyloxy and the like. Further preferred is an ethyleneoxy group or a propyleneoxy group.

In some embodiments, the negative dielectric anisotropic liquid crystal composition of the present invention may further comprise one or more compounds represented by formula iii below.

In the formula III, R₅、R₆Each independently represents an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkenyloxy group having 2 to 5 carbon atoms; and, R₅、R₆Each independently of the other, H on any carbon atom in (a) is optionally substituted with F;

Z₃represents a single bond or-CH₂O-；

q and r each independently represent 0, 1 or 2;

each independently selected from the group consisting of:

preferably, the aforementioned compound represented by the formula III is selected from the group consisting of the compounds represented by the following formulae III-1 to III-17. Wherein R is₅、R₆The definitions of (a) are the same as those described above.

As the aforementioned R₅、R₆The "alkyl group having 1 to 5 carbon atoms" independently of each other may be a straight-chain alkyl group, a branched-chain alkyl group, or a cyclic alkyl group, and is preferably a straight-chain alkyl group. Examples of such a straight-chain alkyl group include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, and an n-pentyl group.

As the aforementioned R₅、R₆Examples of the "alkoxy group having 1 to 5 carbon atoms" which are independently represented include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, n-pentoxy group, and tert-pentoxy group. Further preferred is a methoxy group, an ethoxy group or a n-propoxy group.

As the aforementioned R₅、R₆Examples of the "alkenyl group having 2 to 5 carbon atoms" which are independently represented include an ethenyl group, a propenyl group, a butenyl group, a 2-methylpropenyl group, a 1-pentenyl group, a 2-methyl-1-butenyl group, a 3-methyl-1-butenyl group, and a 2-methyl-2-butenyl group. Further preferred is an ethylene group or a propylene group.

As the aforementioned R₅、R₆Examples of the "alkenyloxy group having 2 to 5 carbon atoms" which are independently represented include an vinyloxy group, a propenyloxy group, a butenyloxy group, a 2-methylpropenyloxy group, a 1-pentenyloxy group, a 2-methyl-1-butenyloxy group, a 3-methyl-1-butenyloxy group, and a 2-methyl-2-butenyloxy group. Further preferred is an ethyleneoxy group or a propyleneoxy group.

In some embodiments, the negative dielectric anisotropic liquid crystal composition of the present invention may further comprise one or more compounds represented by the following formulas IV-1 to IV-8:

the composition of each component in the negative dielectric anisotropic liquid crystal composition of the present invention may be, for example, the following ratio in some embodiments: the amount of the compound represented by the formula I is 1 to 50 parts by mass, the amount of the compound represented by the formula II is 1 to 60 parts by mass, and the amount of the compound represented by the formula III is 1 to 50 parts by mass, based on 100 parts by mass of the liquid crystal composition.

In another embodiment, the liquid crystal composition of the present invention may have a composition of, for example, 1 to 50 parts by mass of the compound represented by formula I, 1 to 60 parts by mass of the compound represented by formula II, 1 to 50 parts by mass of the compound represented by formula III, and 0.01 to 1.00 part by mass of the compound represented by formula IV, based on 100 parts by mass of the liquid crystal composition.

In addition to the liquid crystal compounds listed above, those skilled in the art can add other liquid crystal compounds to the negative dielectric anisotropy liquid crystal composition of the present invention without impairing the desired properties of the liquid crystal composition.

The negative dielectric anisotropic liquid crystal composition of the present invention may optionally contain various functional dopants, and examples of the functional dopants include antioxidants, ultraviolet absorbers, and chiral agents.

[ liquid Crystal display device ]

The second aspect of the present invention provides a liquid crystal display device, which is not particularly limited as long as it contains the liquid crystal composition described in any one of the above. The liquid crystal display device of the present invention may be an active matrix display device or a passive matrix display device. Those skilled in the art can select a suitable liquid crystal display module and a suitable liquid crystal display structure according to the required performance.

Examples

In order to more clearly illustrate the invention, the invention is further described below in connection with preferred embodiments. It is to be understood by persons skilled in the art that the following detailed description is illustrative and not restrictive, and is not to be taken as limiting the scope of the invention.

In the invention, the preparation method is a conventional method unless otherwise specified, the used raw materials can be obtained from a public commercial way unless otherwise specified, the percentages refer to mass percentage, the temperature is centigrade (DEG C), and the liquid crystal compound is also a liquid crystal monomer.

[ liquid Crystal composition having negative dielectric anisotropy ]

Negative dielectric anisotropy liquid crystal compositions with different compositions are prepared in examples 1 to 9 and comparative examples 1 and 2, wherein the monomer structure, the amount (parts by mass) of the specific compound used in each example, and the performance parameter test results of the obtained liquid crystal medium are respectively shown in the following tables 1 to 11.

The temperature units involved in each example are as follows, and the specific meanings and test conditions of other symbols are as follows:

gamma1(mpa.s) represents the rotational viscosity coefficient of the liquid crystal compound, and the measurement method: the equipment INSTEC comprises ALCT-IR1, a vertical box with the thickness of 18 microns in a test box, the temperature of 25 ℃, and the short term G1;

K₁₁is a torsional elastic constant, K₃₃For the splay spring constant, the test conditions were: at 25 ℃, INSTEC, ALCT-IR1 and 18 micron vertical box;

Δ ε represents dielectric anisotropy, and Δ ε_∥-ε_⊥Wherein, epsilon_∥Is a dielectric constant parallel to the molecular axis,. epsilon_⊥For the dielectric constant perpendicular to the molecular axis, test conditions: at 25 ℃, INSTEC, ALCT-IR1 and 18 micron vertical box;

Δ n represents optical anisotropy, and Δ n ═ n_e-n_oWherein n is_oRefractive index of ordinary light, n_eFor the refractive index of extraordinary rays, test conditions: 589nm, 25 + -0.2 deg.C.

VHR represents the voltage holding ratio (%) after ultraviolet irradiation, and the test conditions are 20 +/-2 ℃, voltage +/-5V, pulse width 10ms and voltage holding time 16.7 ms. The testing equipment is TOYO Model 6254 liquid crystal property comprehensive tester. In the ultraviolet photopolymerization of the polymerizable compound for VHR test, the ultraviolet photopolymerization is carried out at a wavelength of 313nm and an irradiation light intensity of 0.5Mw/cm²The ultraviolet light of (2) was irradiated for 2 minutes.

In the present invention, the preparation method of the negative dielectric anisotropy liquid crystal composition is as follows: weighing each liquid crystal monomer according to a certain proportion, putting the liquid crystal monomers into a stainless steel beaker, putting the stainless steel beaker filled with each liquid crystal monomer on a magnetic stirring instrument for heating and melting, adding a magnetic rotor into the stainless steel beaker after most of the liquid crystal monomers in the stainless steel beaker are melted, uniformly stirring the mixture, and cooling to room temperature to obtain the liquid crystal composition.

The obtained liquid crystal composition is filled between two substrates of a liquid crystal display to carry out performance test.

The structures of the liquid crystal monomers used in the examples of the present invention are represented by the following codes, and the methods for representing the codes of the liquid crystal ring structures, the terminal groups, and the linking groups are shown in the following tables (i) and (ii).

Table (one): corresponding code of ring structure

Table (ii): corresponding codes for end groups and linking groups

Examples are:

the liquid crystal compositions of examples 1 to 9 were obtained by compounding the compounds represented by the above formulas I, II, etc. with other components, and the compositions and contents of the components in the liquid crystal compositions of examples 1 to 9 are shown in the following tables 1 to 9.

TABLE 1 component ratios and performance parameters for the liquid crystal composition of example 1

TABLE 2 component ratios and performance parameters for the liquid crystal composition of example 2

TABLE 3 component ratios and performance parameters for the liquid crystal composition of example 3

Table 4 component ratios and performance parameters of the liquid-crystalline medium of example 4

TABLE 5 component ratios and Property parameters of the liquid-crystalline media of example 5

TABLE 6 component ratios and Performance parameters of the liquid-crystalline medium of example 6

TABLE 7 component ratios and performance parameters of the liquid-crystalline media of example 7

TABLE 8 component ratios and Performance parameters of the liquid-crystalline media of example 8

TABLE 9 component ratios and performance parameters for the liquid-crystalline media of example 9

The formulations of comparative example 1 and comparative example 2 are shown in tables 10 and 11 below.

TABLE 10 component ratios and performance parameters of the liquid-crystalline media of comparative example 1

TABLE 11 component ratios and performance parameters of the liquid-crystalline media of comparative example 2

As can be seen from the comparison of examples with comparative examples, examples containing the liquid crystal composition of the present invention used in combination of formula I and formula II can have reduced G1/K while maintaining suitable optical anisotropy value and dielectric anisotropy property, as compared with comparative examples 1 and 2 not containing the combination of formula I and formula II₁₁Or G1/K₃₃The value thus has a fast response time and also an improved VHR value is obtained, thereby enabling display advantages of reduced power consumption and improved stability, which is beneficial for avoiding/reducing the occurrence of display afterimage phenomena.

Although the present invention is not exhaustive of all liquid crystal mixtures claimed, it is anticipated by those skilled in the art that other liquid crystal materials of the same type can be obtained in a similar manner without creative efforts based on the disclosed embodiments, only by combining with their own professional efforts. And are merely representative of embodiments, given the limited space available.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.