WO2021042281A1 - Liquid crystal composition and use thereof - Google Patents

Abstract

A liquid crystal composition having high quality and low power consumption characteristics and suitable for various liquid crystal display devices and PDLC devices, belonging to the field of liquid crystal materials. The liquid crystal composition comprises at least one or more compounds represented by Formula I, at least one or more compounds represented by Formula II and at least one or more compounds represented by Formula III. The liquid crystal composition has large vertical dielectric property, large optical anisotropy and high resistivity; and at the same time, on the premise of ensuring high dielectric property, large optical anisotropy and low driving voltage, the liquid crystal composition effectively increases the voltage retention ratio of mixed liquid crystal, and reduces power consumption, having wide application prospect.

Description

Liquid crystal composition and its application Technical field

The invention relates to a liquid crystal composition, which belongs to the field of liquid crystal display materials and liquid crystal dimming materials, and in particular to a liquid crystal composition with high quality and low power consumption characteristics suitable for various liquid crystal display devices and PDLC devices and the same application.

Background technique

At present, liquid crystals are widely used in the field of information display and dimming. In recent years, the application fields of liquid crystal compounds have significantly expanded to various display devices, electro-optical devices, electronic components, sensors, etc. For this reason, many different structures have been proposed, especially in the field of nematic liquid crystals. So far, nematic liquid crystal compounds have been widely used in flat panel displays and dimming fields.

As consumers demand higher and higher requirements, display materials and dimming materials require more and more attention to the issue of power consumption while requiring low drive. The driving voltage is affected by the dielectric anisotropy of the liquid crystal material. The greater the dielectric anisotropy, the lower the driving voltage. The liquid crystal composition provided by the present invention has high dielectric anisotropy and high voltage retention. The characteristics of this, to achieve the effect of effectively reducing power consumption.

Summary of the invention

The object of the present invention is to provide a liquid crystal composition, which has a large vertical dielectric, large optical anisotropy and high resistivity. The liquid crystal composition includes: at least one or more compounds represented by general formula I, at least one or more compounds represented by general formula II, and at least one or more compounds represented by general formula III;

Wherein, the general formula I has the following structure:

R ₁ represents an alkyl group with 1 to 7 carbon atoms or an alkenyl group with 2 to 7 carbon atoms; L ₁ represents -H or -F; A ₁ represents 1,4-phenylene or 1,4-cyclohexylene; a represents 0 or 1.

The general formula II has the following structure:

R ₂ represents an alkyl group with 1-7 carbon atoms; A ₂ represents 1,4-phenylene or 1,4-cyclohexylene; A ₃ represents

b and c each independently represent 0 or 1.

The general formula III has the following structure:

R ₃ represents an alkyl group with 1 to 7 carbon atoms or an alkenyl group or alkoxy group with 2 to 7 carbon atoms; R ₄ represents an alkyl group with 1 to 7 carbon atoms, an alkoxy group with 1 to 7 carbon atoms, Alkenyl with 2-7 carbon atoms or -F; A ₄ represents 1,4-phenylene or 1,4-cyclohexylene; L ₂ and L ₃ are both -H or -F; d represents 0 or 1.

In the composition provided by the present invention, a compound represented by the general formula IV can be further added; the above-mentioned compound has the characteristics of higher polarity and excellent mutual solubility, and can improve the overall performance of the composition.

The general formula IV has the following structure:

R ₄ represents an alkyl group of 1-7 carbon atoms;

The present invention further proposes that the compound represented by the general formula I is a polar compound containing an ester group structure and a cyano group structure, and the structure has a large dielectric anisotropy.

The compounds represented by the general formula I are one or more of the structures shown in formulas IA to IH:

In the formulas IA to IG, R ₁ represents a direct alkyl group with 1 to 7 carbon atoms; R _{2 in} IH represents a direct alkyl group with 1 to 7 carbon atoms or an alkenyl group with 2 to 7 carbon atoms.

Preferably, in the formulas IA to IG, R ₁ represents a linear alkyl group with 1 to 7 carbon atoms; R _{2 in} IH represents a linear alkyl group with 2 to 5 carbon atoms or a linear alkyl group with 2 to 5 carbon atoms. Alkenyl.

More preferably, the compound represented by the general formula I is selected from one or more of the compounds represented by the formulas IA1 to ~IH5:

Further preferably, the compound represented by the general formula I is selected from one or more of the compounds represented by the formulas IA1 to IA4, IB1 to IB4, and IC1 to IC4, especially one or more of the compounds represented by the formulas IA2 and IB2. Two kinds.

Preferably, the liquid crystal composition provided by the present invention contains 15-60% by weight of the compound represented by general formula I, preferably 30-50% by weight of the compound represented by general formula I, more preferably 35-42 % By weight of the compound represented by the general formula I.

The present invention further proposes that the compound represented by the general formula II is a polar compound containing a 3,4,5-trifluorobenzene structure and a difluoromethoxy bridge bond or 2-methyl-3,4,5 -A polar compound with trifluorobenzene structure and difluoromethoxy bridge bond. This structure has large dielectric anisotropy and high resistivity. The compound represented by the general formula II is one or more of the structures shown in formulas IIA to IIF:

In the formulas IIA to IIF, R ₂ represents a linear alkyl group of 1 to 7 carbon atoms;

Preferably, in formula IIA to formula IIF, R ₂ represents a linear alkyl group of 2 to 5 carbon atoms;

More preferably, the compound represented by the general formula II is selected from one or more of the compounds represented by the formula IIA1 to the formula IIF4:

Preferably, the liquid crystal composition provided by the present invention contains 3-30% by weight of the compound represented by general formula II, preferably 5-20% by weight of the compound represented by general formula II, more preferably 5-15 % By weight of the compound represented by Formula II.

The present invention further proposes that the compound represented by the general formula III contains an acetylene bond structure, which has large optical anisotropy. The compound represented by the general formula III is one or more of the structures shown in formula IIIA, formula IIIB, and formula IIIC:

In the formulas IIIA, IIIB and IIIC, R ₃ represents a linear alkyl group with 1 to 7 carbon atoms, a linear alkoxy group with 1 to 7 carbon atoms or a linear alkenyl group with 2 to 7 carbon atoms ; R ₄ represents a straight chain alkyl group with 1 to 7 carbon atoms, a straight chain alkoxy group with 1 to 7 carbon atoms, a straight chain alkenyl group with 2 to 7 carbon atoms or -F;

Preferably, in the formulas IIIA, IIIB and IIIC, R ₃ represents a linear alkyl group with 2 to 8 carbon atoms; R ₄ represents a linear alkyl group with 1 to 5 carbon atoms, Atom straight-chain alkoxy group or straight-chain alkenyl group with 2 to 5 carbon atoms;

More preferably, the compound represented by the general formula III is selected from one or more of the compounds represented by formula IIIA1 to formula IIIA3, formula IIIB1 to formula IIIB4, and formula IIIC1 to formula IIIC9:

More preferably, the compound represented by the general formula III is selected from one or more of IIIA1, IIIA2, and IIIA3.

Preferably, the liquid crystal composition provided by the present invention contains 20-60% by weight of the compound represented by general formula III, preferably 30-50% by weight of the compound represented by general formula III, more preferably 35-48 % By weight of the compound represented by Formula III.

The present invention further proposes that the compound represented by the general formula IV contains a cyano group structure, which has large dielectric anisotropy and excellent mutual solubility. The compound represented by general formula IV is selected from one or more of the compounds represented by formula IV1 to IV4:

Preferably, the liquid crystal composition provided by the present invention contains 0-20% by weight of the compound represented by general formula IV, preferably 4-12% by weight of the compound represented by general formula IV, and more preferably 5-10% by weight. % By weight of the compound represented by formula IV.

The present invention further proposes that the liquid crystal composition contains the following compounds by weight percentage:

1) 15-60% of the compound represented by general formula I,

2) 3-30% of the compound represented by general formula II,

3) 20-60% of the compound represented by general formula III,

4) 0-20% of the compound represented by general formula IV.

Preferably, the liquid crystal composition contains the following components by weight percentage:

1) 30-50% of the compound represented by general formula I,

2) 5-20% of the compound represented by general formula II,

3) 30-50% of the compound represented by general formula III,

4) 4-12% of the compound represented by general formula IV.

More preferably, the liquid crystal composition contains the following components by weight percentage:

1) 35-42% of the compound represented by general formula I,

2) 5-15% of the compound represented by general formula II,

3) 35 to 48% of the compound represented by general formula III,

4) 5-10% of the compound represented by general formula IV.

The compound represented by the liquid crystal composite species provided by the present invention has high positive dielectric anisotropy (+△ε), and the compound represented by general formula II has high positive dielectric anisotropy (+△ε) And has a high charge retention rate, the compound represented by general formula III has the characteristics of large optical anisotropy, and the compound represented by general formula IV has good mutual solubility and positive dielectric anisotropy. The synergy between the components can achieve excellent performance.

In order to improve the stability of the liquid crystal composition to heat and light, especially ultraviolet light, ultraviolet absorbers can also be added according to the situation, such as: benzotriazoles, benzophenones, triazines, benzoates; hindered Amine light stabilizer; hindered phenolic antioxidant.

The preparation method of the liquid crystal composition of the present invention is not particularly limited, and can be prepared by conventional methods, for example, mixing two or more liquid crystal compounds at high temperature and dissolving each other, that is, dissolving the liquid crystal compound in the solvent used for the compound and Mix, and then distill the solvent out under reduced pressure; or dissolve the smaller content in the main component with a larger content at a higher temperature, or dissolve each component in an organic solvent, Then, the solution is mixed and the solvent is removed. Among them, the solvent used can be common organic solvents such as acetone, chloroform or methanol.

The liquid crystal composition of the present invention can be used in liquid crystal display devices and liquid crystal dimming devices, and is particularly suitable for PDLC devices.

In the present invention _{, the liquid crystal composition obtained by mixing -CF 2} O-containing monomers, cyano group-containing monomers and alkyne group-containing monomers to obtain a liquid crystal composition, under the premise of ensuring high dielectric, large optical anisotropy and low driving voltage, It effectively increases the voltage holding rate of the mixed liquid crystal, reduces the power consumption, and has broad application prospects.

detailed description

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

Unless otherwise specified, percentages in the present invention are percentages by weight; temperature units are degrees Celsius; Cp represents the clearing point of the liquid crystal composition (unit: °C); △n represents optical anisotropy (test conditions: 20℃); △ε represents Dielectric anisotropy (test conditions: 25°C, 1000Hz); VHR represents voltage holding rate (test conditions: 60°C, drive voltage 1V hold for 0.3ms, release 6.5ms; unit: %);

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

Table 1: Group structure codes of liquid crystal compounds

Take the following compound structure as an example:

Expressed as: 3PGUQUF

Expressed as: V2PZUCN

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 percentage and performance parameters of each component in the liquid crystal composition

Example 2

Table 3 The weight percentage and performance parameters of each component in the liquid crystal composition

Example 3

Table 4 The weight percentage and performance parameters of each component in the liquid crystal composition

Example 4

Table 5 The weight percentage and performance parameters of each component in the liquid crystal composition

Example 5

Table 6 The weight percentage and performance parameters of each component in the liquid crystal composition

Example 6

Table 7 The weight percentage and performance parameters of each component in the liquid crystal composition

Example 7

Table 8 The weight percentage and performance parameters of each component in the liquid crystal composition

Example 8

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

Example 9

Table 10 The weight percentage and performance parameters of each component in the liquid crystal composition

Example 10

Table 11 The weight percentage and performance parameters of each component in the liquid crystal composition

Comparative example 1

Table 12: Weight percentage and performance parameters of each component in the liquid crystal composition

The performance parameter values of the liquid crystal compositions obtained in Example 1 and Comparative Example 1 are summarized and compared, see Table 13.

Table 13: Comparison of performance parameters of liquid crystal compositions

To	Cp	△n	Δε	VHR
Example 1	108	0.251	24.1	80
Comparative example 1	106	0.252	24.6	70

The comparison shows that the threshold voltage, optical anisotropy, and dielectric anisotropy of the liquid crystal mixture provided in Example 1 are basically the same as those of Comparative Example 1. In this case, the VHR of the liquid crystal mixture provided in Example 1 is higher. This means that the liquid crystal provided by the present invention has lower power consumption and can effectively save energy when the driving voltage and other conditions are similar.

It can be seen from the above examples that the liquid crystal composition provided by the present invention contains both a highly polar dielectric anisotropic compound and a large optical anisotropic compound, and has the characteristics of low threshold, large optical anisotropy, and high VHR, and is effective The ground has lower power consumption while ensuring a low threshold. Therefore, the liquid crystal composition provided by the present invention is suitable for various display devices and PDLC devices.

Industrial applicability

The invention provides a liquid crystal composition with high quality and low power consumption characteristics suitable for various liquid crystal display devices and PDLC devices. The liquid crystal composition includes at least one or more compounds represented by the general formula I, at least one or more compounds represented by the general formula II, and at least one or more compounds represented by the general formula III. The liquid crystal composition provided by the present invention has a large vertical dielectric, large optical anisotropy, and high resistivity; at the same time, it effectively increases the The voltage retention rate of the mixed liquid crystal is reduced, the power consumption is reduced, and the hybrid liquid crystal has good economic value and application prospects.

Claims (9)

1. A liquid crystal composition, characterized in that the composition comprises: at least one or more compounds represented by the general formula I:

   

   Wherein, R ₁ represents an alkyl group with 1 to 7 carbon atoms or an alkenyl group with 2 to 7 carbon atoms; L ₁ represents -H or -F; A ₁ represents 1,4-phenylene or 1,4-cyclic ring Hexyl; a represents 0 or 1;

   And at least one or more compounds represented by general formula II:

   

   Wherein, R ₂ represents an alkyl group with 1-7 carbon atoms; A ₂ represents 1,4-phenylene or 1,4-cyclohexylene; A ₃ represents

   

   b and c each independently represent 0 or 1;

   And at least one or more compounds represented by general formula III:

   

   Wherein, R ₃ represents an alkyl group with 1 to 7 carbon atoms or an alkenyl group or alkoxy group with 2 to 7 carbon atoms; R ₄ represents an alkyl group with 1 to 7 carbon atoms or an alkoxy group with 1 to 7 carbon atoms Group, an alkenyl group with 2-7 carbon atoms or -F; A ₄ represents 1,4-phenylene or 1,4-cyclohexylene; L ₂ and L ₃ are both -H or -F; d represents 0 or 1.
2. The liquid crystal composition of claim 1, wherein the composition further comprises a compound represented by general formula IV:

   

   Wherein, R ₄ represents an alkyl group of 1 to 7 carbon atoms.
3. The liquid crystal composition according to claim 1 or 2, wherein the compound represented by the general formula I is one or more of the structures represented by the formulas IA to IH:

   

   _{Wherein, R 1} in the formulas IA to IG represents a direct-attached alkyl group with 1 to 7 carbon atoms; R ₂ in the formula IH represents a direct-attached alkyl group with 1 to 7 carbon atoms or 2-7 Alkenyl of carbon atom;

   _{Preferably, R 1} in the formulas IA to IG represents a linear alkyl group of 1 to 7 carbon atoms; R ₂ in the formula IH represents a linear alkyl group of 2 to 5 carbon atoms or 2 to 5 Alkenyl of three carbon atoms;

   More preferably, the compound represented by the general formula I is selected from one or more of the compounds represented by the formulas IA1 to ~IH5:

   

   

   

   

   Preferably, the compound represented by the general formula I is selected from one or more of the compounds represented by formulas IA-1 to IA-4, IB1 to IB4, and IC-1 to IC-4, preferably selected from the group consisting of One or both of IA2 and IB2;

   Preferably, the liquid crystal composition contains 15-60% by weight of the compound represented by general formula I, preferably 30-50% by weight of the compound represented by general formula I, more preferably 35-42% by weight The compound represented by the general formula I.
4. The liquid crystal composition according to any one of claims 1 to 3, wherein the compound represented by the general formula II is one or more of the structures represented by the formulas IIA to IIF:

   

   _{Wherein, R 2} in the formula IIA to formula IIF represents a linear alkyl group with 1 to 7 carbon atoms;

   _{Preferably, R 2} in the formula IIA to formula IIF represents a linear alkyl group of 2 to 5 carbon atoms;

   More preferably, the compound represented by the general formula II is selected from one or more of the compounds represented by the formula IIA1 to the formula IIF4:

   

   

   Preferably, the liquid crystal composition contains 3-30% by weight of the compound represented by general formula II, preferably 5-20% by weight of the compound represented by general formula II, more preferably 5-15% by weight The compound represented by the general formula II.
5. The liquid crystal composition according to any one of claims 1 to 4, wherein the compound represented by the general formula III is one or more of the structures represented by the formula IIIA, the formula IIIB, and the formula IIIC:

   

   _{Wherein, R 3 in} the formulas IIIA, IIIB and IIIC represents a linear alkyl group with 1 to 7 carbon atoms, a linear alkoxy group with 1 to 7 carbon atoms, or a linear chain with 2 to 7 carbon atoms. Alkenyl; R ₄ represents a linear alkyl group with 1 to 7 carbon atoms, a linear alkoxy group with 1 to 7 carbon atoms, a linear alkenyl group with 2 to 7 carbon atoms or -F;

   _{Preferably, R 3 in} the formulas IIIA, IIIB and IIIC represents a linear alkyl group with 2 to 8 carbon atoms; R ₄ represents a linear alkyl group with 1 to 5 carbon atoms and 1 to 5 carbon atoms. Atom straight-chain alkoxy group or straight-chain alkenyl group with 2 to 5 carbon atoms;

   More preferably, the compound represented by the general formula III is selected from one or more of the compounds represented by formula IIIA1 to formula IIIA3, formula IIIB1 to formula IIIB4, and formula IIIC1 to formula IIIC9:

   

   

   More preferably, the compound represented by the general formula III is selected from one or more of IIIA1, IIIA2, and IIIA3;

   Preferably, the liquid crystal composition contains 20 to 60% by weight of the compound represented by general formula III, preferably 30 to 50% by weight of the compound represented by general formula III, more preferably 35 to 48% by weight The compound represented by the general formula III.
6. The liquid crystal composition according to any one of claims 1 to 5, wherein the compound represented by the general formula IV is selected from one or more of the compounds represented by the formulas IV1 to IV4:

   

   Preferably, the liquid crystal composition contains 0-20% by weight of the compound represented by general formula IV, preferably 4-12% by weight of the compound represented by general formula IV, more preferably 5-10% by weight The compound represented by the general formula IV.
7. 7. The liquid crystal composition according to any one of claims 2-6, wherein the liquid crystal composition comprises the following compound by weight percentage:

   1) 15-60% of the compound represented by general formula I,

   2) 3-30% of the compound represented by general formula II,

   3) 20-60% of the compound represented by general formula III,

   4) 0-20% of the compound represented by general formula IV;

   Preferably, the liquid crystal composition contains the following components by weight percentage:

   1) 30-50% of the compound represented by general formula I,

   2) 5-20% of the compound represented by general formula II,

   3) 30-50% of the compound represented by general formula III,

   4) 4-12% of the compound represented by general formula IV;

   More preferably, the liquid crystal composition contains the following components by weight percentage:

   1) 35-42% of the compound represented by general formula I,

   2) 5-15% of the compound represented by general formula II,

   3) 35 to 48% of the compound represented by general formula III,

   4) 5-10% of the compound represented by general formula IV.
8. 7. The liquid crystal composition of any one of claims 1-7, wherein the liquid crystal composition further comprises an ultraviolet absorber, a hindered amine light stabilizer, and a hindered phenol antioxidant;

   Preferably, the ultraviolet absorbers are benzotriazoles, benzophenones, triazines, and benzoates.
9. The use of the liquid crystal composition of any one of claims 1-8 in a liquid crystal display device and a liquid crystal dimming device.