CN114806598A - A kind of negative liquid crystal composition with high contrast and its application - Google Patents

Abstract

The invention relates to the field of liquid crystal materials, in particular to a negative liquid crystal composition with high contrast and application thereof. The liquid crystal composition obtained by combining the compounds shown in the general formulas I, II, III and IV can simultaneously meet the requirements of large elastic constant and low rotational viscosity, thereby realizing a liquid crystal display with high contrast.

Description

A kind of negative liquid crystal composition with high contrast and its application

technical field

The present invention relates to the field of liquid crystal materials, in particular to a negative liquid crystal composition with high contrast and its application.

Background technique

At present, LCD monitors, as the most mainstream monitors, have been widely used in various products. Among them, IPS and FFS mode monitors are widely used in mobile phones, notebook computers, tablet computers because of their unique hard screen characteristics and very wide viewing angle characteristics. Computers, computer monitors, televisions, etc.

The planar arrangement of IPS and FFS liquid crystals leads to light leakage easily in the dark state, and the contrast performance is obviously inferior to VA type (MVA, PVA, UV2A, PSVA) displays. After research, it has been found that when the liquid crystal molecules are initially arranged, the alignment debris on the surface of the alignment layer will cause the liquid crystal molecules to be disordered, resulting in light leakage in the dark state. Through research, it is found that the increase of the elastic constant of liquid crystal helps to improve the alignment of liquid crystal molecules.

Based on this, the applicant's research and development team has also developed a series of negative liquid crystal compositions with high contrast, such as CN113072958A. However, with the increasing market requirements, it is still necessary to provide a better effect with higher Contrast negative liquid crystal compositions.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a negative liquid crystal composition with high contrast ratio and application thereof, the liquid crystal composition has a large elastic constant, can improve the contrast ratio of liquid crystal display, and at the same time, the liquid crystal composition has a negative dielectric anisotropy Anisotropy, used in liquid crystal displays to have higher transmittance and improve the effect of flickering of liquid crystal displays.

The present invention provides a negative liquid crystal composition with high contrast, comprising at least one compound represented by general formula I, at least one compound represented by general formula II, at least one compound represented by general formula III, and at least one general formula a compound represented by formula IV;

Wherein, R ₁ and R ₂ each independently represent an alkyl group of 1-7 carbon atoms, an alkoxy group of 1-7 carbon atoms or an alkenyl group of 2-7 carbon atoms;

R ₃ and R ₄ independently represent an alkyl group of 1-7 carbon atoms, an alkoxy group of 1-7 carbon atoms or an alkenyl group of 2-7 carbon atoms;

R ₅ represents an alkyl group of 1-7 carbon atoms, an alkoxy group of 1-7 carbon atoms or an alkenyl group of 2-7 carbon atoms; R ₆ represents an alkyl group of 1-7 carbon atoms or an alkyl group of 1-7 carbon atoms alkoxy groups of carbon atoms;

R ₇ and R ₈ each independently represent an alkyl group of 1-7 carbon atoms, an alkoxy group of 1-7 carbon atoms or an alkenyl group of 2-7 carbon atoms.

It is well known in the art that in general, the purpose of improving the elastic constant can be achieved by increasing the clearing point of the liquid crystal composition, but with the increase of the clearing point, the rotational viscosity of the liquid crystal composition increases, resulting in a slower response time of the liquid crystal display, that is, it is difficult to Take into account the elastic constant and rotational viscosity. After a lot of researches in the present invention, it is found that the liquid crystal composition obtained by combining the compounds represented by the general formulas I, II, III and IV can satisfy the requirements of having a large elastic constant and a low rotational viscosity at the same time, thereby realizing a high-contrast liquid crystal display. .

Wherein, the compound represented by the general formula I is a bicyclic compound containing an ethylene bond, and the compound has a large elastic constant, a low rotational viscosity and a refractive index; the compound represented by the general formula II is a tricyclic compound containing an ethylene bond Bonded compound, the compound has a large elastic constant, low rotational viscosity and refractive index, which is very helpful for improving the contrast; the compound represented by the general formula III is a negative dielectric anisotropy compound of cyclohexene structure , the compound has a large elastic constant; the compound represented by the general formula IV is a compound containing bicyclohexane, and the compound has good low-temperature solubility. Combining these four compounds works better than other existing combinations, achieving high contrast without negatively impacting other properties, or even a positive boost.

According to the negative liquid crystal composition with high contrast provided by the present invention,

The content of the compound represented by the general formula I is 1 to 30 wt.%,

The content of the compound represented by the general formula II is 1-60 wt.%,

The content of the compound represented by the general formula III is 1-40 wt.%,

The content of the compound represented by the general formula IV is 1-50 wt.%.

Preferably, the liquid crystal composition includes the following components:

2 to 25 wt.% of the compound represented by the general formula I,

3 to 55 wt.% of the compound represented by the general formula II,

3 to 35 wt.% of the compound represented by the general formula III, and

5-45 wt.% of the compound represented by the general formula IV.

Further preferably, the liquid crystal composition includes the following components:

3 to 20 wt.% of the compound represented by the general formula I,

10 to 50 wt.% of the compound represented by the general formula II,

5 to 30 wt.% of the compound represented by the general formula III, and

5-40 wt.% of the compound represented by the general formula IV.

More preferably, the liquid crystal composition includes the following components:

5～15wt.% of the compound represented by the general formula I,

20 to 45 wt.% of the compound represented by the general formula II,

10 to 25 wt.% of the compound represented by the general formula III, and

10-35 wt.% of the compound represented by the general formula IV.

In the present invention, the dosage of each component is controlled within the above-mentioned ratio range, which can ensure a more significant synergistic effect among the components in the composition, and improve various properties of the liquid crystal composition.

According to the negative liquid crystal composition with high contrast provided by the present invention, the compound represented by the general formula I is selected from one or more of the compounds represented by IA1-IA20, IB1-IB20 and IC1-IC16:

Preferably, the compound represented by the general formula I is selected from one or more of IB7-IB16.

According to the negative liquid crystal composition with high contrast provided by the present invention, the compound represented by the general formula II is selected from one or more of the compounds represented by IIA1-IIA20, IIB1-IIB20, and IIC1-IIC14:

Preferably, the compound represented by the general formula II is selected from one or more of IIB5-IIB18.

According to the negative liquid crystal composition with high contrast provided by the present invention, the compound represented by the general formula III is selected from one or more of the compounds represented by IIIA1-IIIA24 and IIIB1-IIIB24:

Preferably, the compound represented by the general formula III is selected from one or more of IIIA13-IIIA22.

According to the negative liquid crystal composition with high contrast provided by the present invention, the compound represented by the general formula IV is selected from one or more of the compounds represented by IVA1-IVA12 and IVB1-IVB14:

Preferably, the compound represented by the general formula IV is selected from one or more of IVA1-IVA4 and IVB6-IVB9.

According to the negative liquid crystal composition with high contrast provided by the present invention, the liquid crystal composition further comprises one or more compounds represented by the general formula V,

Wherein, R ₉ and R ₁₀ each independently represent an alkyl group of 1-7 carbon atoms or an alkoxy group of 1-7 carbon atoms.

The compound represented by the general formula V of the present invention is a tetrabiphenyl compound, which is added to the liquid crystal composition to help coordinate the compound represented by the general formula I to the general formula IV of the present invention, and further improve the high temperature of the liquid crystal composition. Reliability.

In the liquid crystal composition provided by the present invention, when the total mass of all its components is 100%, the content of the compound represented by the general formula V in the composition is preferably 0-10%, preferably 0-5% , more preferably 0 to 3%, more preferably 0 to 1%. At this time, it is more beneficial to improve the response time of the liquid crystal display.

Preferably, the compound represented by the general formula V is selected from one or more of the compounds represented by V1-V8:

In the case of containing the compound represented by the general formula V, in order to ensure that the synergistic effect between the components is more significant, the liquid crystal composition includes the following components:

2 to 25 wt.% of the compound represented by the general formula I,

3 to 55 wt.% of the compound represented by the general formula II,

3 to 35 wt.% of the compound represented by the general formula III,

5 to 45 wt.% of the compound represented by the general formula IV, and

0.01-3 wt.% of the compound represented by the general formula V.

More preferably, the liquid crystal composition includes the following components:

5～15wt.% of the compound represented by the general formula I,

20 to 45 wt.% of the compound represented by the general formula II,

10 to 25 wt.% of the compound represented by the general formula III,

10 to 35 wt.% of the compound represented by the general formula IV, and

0.1 to 1 wt.% of the compound represented by the general formula V.

According to the negative liquid crystal composition with high contrast provided by the present invention, the liquid crystal composition further comprises one or more compounds represented by the general formula VI,

Wherein, R ₁₁ represents an alkyl group of 1-7 carbon atoms, an alkoxy group of 1-7 carbon atoms or an alkenyl group of 2-7 carbon atoms; R ₁₂ represents an alkyl group of 1-7 carbon atoms or 1 -Alkoxy of 7 carbon atoms.

The compound represented by the general formula VI of the present invention is a negative compound containing a tricyclic ring, and the compound has a high clearing point, which can effectively improve the clearing point of the liquid crystal composition. When the total mass of all components of the liquid crystal composition is 100%, the content of the compound represented by the general formula VI in the composition is preferably 0-40%, preferably 5-35%, more preferably 10-30% %, more preferably 15 to 25%. At this time, it is more beneficial to improve the working temperature range of the liquid crystal display.

Preferably, the compound represented by the general formula VI is selected from one or more of the compounds represented by VIA1-VIA24 and VIB1-VIB24:

In the case of containing the compound represented by the general formula VI, in order to ensure that the synergistic effect between the components is more significant, the liquid crystal composition includes the following components:

3 to 20 wt.% of the compound represented by the general formula I,

10 to 50 wt.% of the compound represented by the general formula II,

5-30 wt.% of the compound represented by the general formula III,

5 to 40 wt.% of the compound represented by the general formula IV, and

5-35 wt.% of the compound represented by the general formula VI.

More preferably, the liquid crystal composition includes the following components:

5～15wt.% of the compound represented by the general formula I,

20 to 45 wt.% of the compound represented by the general formula II,

10 to 25 wt.% of the compound represented by the general formula III,

10 to 35 wt.% of the compound represented by the general formula IV, and

10-30 wt.% of the compound represented by the general formula VI.

The preparation method of the liquid crystal composition of the present invention is not particularly limited, and can be produced by mixing two or more compounds by conventional methods, such as by mixing different components at high temperature and dissolving each other. The compound is dissolved in the solvent used for the compound and mixed, and then the solvent is distilled off under reduced pressure; or the liquid crystal composition of the present invention can be prepared according to a conventional method, such as placing the component with a smaller content in a higher It is obtained by dissolving in the main components with a large content at a high temperature, or dissolving each component in an organic solvent, such as acetone, chloroform or methanol, etc., and then mixing the solutions to remove the solvent.

The present invention also provides the application of the above negative liquid crystal composition with high contrast in VA, IPS or FFS mode liquid crystal displays.

The liquid crystal composition of the present invention has low rotational viscosity, large elastic constant, good low temperature mutual solubility and fast response speed under preferred conditions, and can be used for fast response liquid crystal display of various display modes. The use in IPS or FFS mode monitors can significantly improve the display effect of LCD monitors, especially for IPS and FFS mode LCD monitors.

The present invention provides a negative liquid crystal composition with high contrast and its application. The liquid crystal composition obtained by combining the compounds represented by the general formulas I, II, III and IV in the present invention can satisfy the requirements of having a large elastic constant and Has low rotational viscosity, enabling high contrast liquid crystal displays.

Detailed ways

The following examples are intended to illustrate the present invention, but not to limit the scope of the present invention.

Unless otherwise specified, the percentages in the present invention are weight percentages; the temperature is in degrees Celsius; Δn represents optical anisotropy (25°C); Δε represents dielectric anisotropy (25°C, 1000Hz); γ1 represents rotational viscosity ( mPa.s, 25°C); Cp represents the clearing point (°C) of the liquid crystal composition; K ₁₁ , K ₂₂ , K ₃₃ represent the splay, twist and bending elastic constants (pN, 25° C), respectively.

In the following examples, the group structure in the liquid crystal compound is represented by the codes shown in Table 1.

Table 1 Group Structure Codes of Liquid Crystal Compounds

Take the following compound structure as an example:

表示为：5CC2WO3

Represented as: 5CC2WO3

表示为：3CLWO2

Represented as: 3CLWO2

In the following examples, the preparation of the liquid crystal composition adopts the thermal dissolution method, which includes the following steps: weighing the liquid crystal compound by weight percentage with a balance, wherein there is no specific requirement for the order of weighing and adding, usually the melting point of the liquid crystal compound is from high to low. Weighing and mixing in sequence, heating and stirring at 60-100°C to make each component melt evenly, then filtering, rotary steaming, and finally encapsulating to obtain the target sample.

In the following examples, the weight percentage of each component in the liquid crystal composition and the performance parameters of the liquid crystal composition are shown in the following table.

Example 1

Table 2 The weight percent and performance parameters of each component in the liquid crystal composition

Example 2

Table 3 Weight percent and performance parameters of each component in the liquid crystal composition

Example 3

Table 4 Weight percent and performance parameters of each component in the liquid crystal composition

Example 4

The weight percent and performance parameters of each component in table 5 liquid crystal composition

Example 5

Table 6 Weight percent and performance parameters of each component in the liquid crystal composition

Example 6

Table 7 Weight percent and performance parameters of each component in the liquid crystal composition

Example 7

Table 8 Weight percent and performance parameters of each component in the liquid crystal composition

Example 8

The weight percent and performance parameters of each component in the liquid crystal composition of Table 9

Example 9

Table 10 Weight percent and performance parameters of each component in the liquid crystal composition

Example 11

Table 12 The weight percent and performance parameters of each component in the liquid crystal composition

Example 12

Table 13 Weight percent and performance parameters of each component in the liquid crystal composition

Example 13

Table 14 Weight percent and performance parameters of each component in the liquid crystal composition

Example 14

Table 15 Weight percent and performance parameters of each component in the liquid crystal composition

Example 15

Table 16 The weight percent and performance parameters of each component in the liquid crystal composition

Example 16

Table 17 Weight percent and performance parameters of each component in the liquid crystal composition

Example 17

Table 18 Weight percent and performance parameters of each component in the liquid crystal composition

Example 18

Table 19 Weight percent and performance parameters of each component in the liquid crystal composition

Example 19

Table 20 The weight percent and performance parameters of each component in the liquid crystal composition

Example 20

Table 21 The weight percent and performance parameters of each component in the liquid crystal composition

Example 21

Table 22 The weight percent and performance parameters of each component in the liquid crystal composition

Example 22

Table 23 The weight percent and performance parameters of each component in the liquid crystal composition

Example 23

Table 24 Weight percent and performance parameters of each component in the liquid crystal composition

Example 24

Table 25 The weight percent and performance parameters of each component in the liquid crystal composition

Example 25

Table 26 The weight percent and performance parameters of each component in the liquid crystal composition

Example 26

Table 27 The weight percent and performance parameters of each component in the liquid crystal composition

Example 27

Table 28 The weight percent and performance parameters of each component in the liquid crystal composition

Comparative Example 1

Table 29 Weight percent and performance parameters of each component in the liquid crystal composition

Comparative Example 2

Table 30 Weight percent and performance parameters of each component in the liquid crystal composition

Compared with Comparative Example 1 and Comparative Example 2, Example 1 and Example 27 have larger elastic constants and thus higher contrast ratios.

It can be seen from the above examples that the liquid crystal composition provided by the present invention has large elastic constant, high resistivity, suitable optical anisotropy, good low temperature mutual solubility, low rotational viscosity and excellent light stability and thermal stability. The stability can reduce the response time of the liquid crystal display, thereby solving the problem of the slow response speed of the liquid crystal display. Therefore, the liquid crystal composition provided by the present invention is suitable for fast response VA, IPS and FFS type TFT liquid crystal display devices, especially suitable for IPS and FFS liquid crystal display devices.

Although the present invention has been described in detail above with general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made on the basis of the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention fall within the scope of the claimed protection of the present invention.

Claims (10)

1. A negative liquid crystal composition with high contrast is characterized by comprising at least one compound shown as a general formula I, at least one compound shown as a general formula II, at least one compound shown as a general formula III and at least one compound shown as a general formula IV;

wherein R is ₁ 、R ₂ Each independently represents an alkyl group of 1 to 7 carbon atoms, an alkoxy group of 1 to 7 carbon atoms or an alkenyl group of 2 to 7 carbon atoms;

R ₃ 、R ₄ each independently represents an alkyl group of 1 to 7 carbon atoms, an alkoxy group of 1 to 7 carbon atoms or an alkenyl group of 2 to 7 carbon atoms;

R ₅ represents an alkyl group of 1 to 7 carbon atoms, an alkoxy group of 1 to 7 carbon atoms or an alkenyl group of 2 to 7 carbon atoms; r ₆ Represents an alkyl group of 1 to 7 carbon atoms or an alkoxy group of 1 to 7 carbon atoms;

R ₇ 、R ₈ each independently represents an alkyl group of 1 to 7 carbon atoms, an alkoxy group of 1 to 7 carbon atoms or an alkenyl group of 2 to 7 carbon atoms.

2. The negative liquid crystal composition with high contrast of claim 1, wherein the compound of formula I is present in an amount of 1 to 30 wt.%,

the content of the compound shown in the general formula II is 1-60 wt.%,

the content of the compound shown in the general formula III is 1-40 wt.%,

the content of the compound shown in the general formula IV is 1-50 wt.%.

3. The negative liquid crystal composition with high contrast of claim 1, wherein the compound represented by formula I is selected from one or more of the compounds represented by IA1-IA20, IB1-IB20, and IC1-IC 16:

preferably, the compound shown in the general formula I is selected from one or more of IB7-IB 16.

4. The negative liquid crystal composition of claim 1, wherein the compound represented by formula II is one or more compounds selected from the group consisting of IIA1-IIA20, IIB1-IIB20, IIC1-IIC 14:

preferably, the compound shown in the general formula II is selected from one or more of IIB5-IIB 18.

5. The negative liquid crystal composition of claim 1, wherein the compound of formula III is selected from one or more of the compounds represented by IIIA1-IIIA24, IIIB1-IIIB 24:

preferably, the compound shown in the general formula III is selected from one or more of IIIA13-IIIA 22.

6. The negative liquid crystal composition with high contrast of claim 1, wherein the compound of formula IV is selected from one or more of the compounds represented by IVA1-IVA12, IVB1-IVB 14:

preferably, the compound shown in the general formula IV is selected from one or more of IVA1-IVA4, IVB6-IVB 9.

7. The negative liquid crystal composition with high contrast of claim 1, wherein the liquid crystal composition further comprises one or more compounds represented by formula V,

wherein R is ₉ 、R ₁₀ Each independently represents an alkyl group of 1 to 7 carbon atoms or an alkoxy group of 1 to 7 carbon atoms;

preferably, the compound represented by the general formula V is selected from one or more of the compounds represented by V1-V8:

8. the negative liquid crystal composition with high contrast of claim 1, wherein the liquid crystal composition further comprises one or more compounds represented by formula VI,

wherein R is ₁₁ Represents an alkyl group of 1 to 7 carbon atoms, an alkoxy group of 1 to 7 carbon atoms or an alkenyl group of 2 to 7 carbon atoms; r ₁₂ Represents an alkyl group of 1 to 7 carbon atoms or an alkoxy group of 1 to 7 carbon atoms;

preferably, the compound shown in the general formula VI is selected from one or more of the compounds represented by VIA1-VIA24 and VIB1-VIB 24:

9. negative liquid crystal composition with high contrast according to claim 7 or 8, characterized in that it comprises the following components:

2 to 25 wt.% of a compound of the formula I,

3 to 55 wt.% of a compound of formula II,

3 to 35 wt.% of a compound of the formula III,

5 to 45 wt.% of a compound of the formula IV, and

0.01 to 3 wt.% of a compound represented by formula V;

or,

3 to 20 wt.% of a compound of formula I,

10 to 50 wt.% of a compound of formula II,

5 to 30 wt.% of a compound of the formula III,

5 to 40 wt.% of a compound of the formula IV, and

5 to 35 wt.% of a compound of formula VI.

10. Use of a negative liquid crystal composition having a high contrast ratio according to any one of claims 1 to 9 in a VA, IPS or FFS mode liquid crystal display.