Liquid crystal composition and use thereof

Abstract

A liquid crystal composition and a use thereof, the liquid crystal composition comprising one or more compounds of general formula I, one or more compounds of general formula II, one or more compounds of general formula III, and one or more compounds of general formula IV. The composition may further comprise one or more compounds of general formula V and one or more compounds of general formula VI. The liquid crystal composition is suitable for liquid crystal displays.

Description

A liquid crystal composition and its application

[0001] Cross-referencing

[0002] This application claims priority to Chinese Patent Application No. 202411443095.4, filed on October 16, 2024, entitled “A Liquid Crystal Composition and Its Application Therein,” the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] This invention relates to the field of liquid crystal materials technology, and in particular to a liquid crystal composition and its application, specifically to a liquid crystal composition containing cyclopentene and dibenzothiophene and its application. Background Technology

[0004] Currently, LCD (Liquid Crystal Display) technology is mature, successfully solving technical challenges such as viewing angle, resolution, color saturation, and brightness. Its display performance is approaching or surpassing that of CRT monitors. Large-size and small-to-medium-size LCDs have gradually become the mainstream flat panel display in their respective fields. However, due to the limitations of the liquid crystal material itself (high viscosity), response time has become a major factor affecting the performance of high-performance displays.

[0005] Negative liquid crystal displays were proposed in the late 1980s, primarily for VA mode. Their main advantage is high contrast, while their main disadvantages are narrow viewing angles and slow response times. With the development of display technology, technologies such as MVA, PVA, and PSVA have emerged, improving response time and viewing angles to some extent. In recent years, with touchscreens becoming mainstream in the mobile device market, IPS and FFS hard-screen displays have an inherent advantage. IPS and FFS displays can use either positive or negative liquid crystals. Due to the bending electric field present in these displays, positive liquid crystals align along the electric field lines, causing molecular bending and resulting in decreased transmittance; negative liquid crystals align perpendicular to the electric field lines, thus significantly increasing transmittance. This is currently the best method to improve transmittance and reduce backlight power consumption. However, the response time problem of negative liquid crystals remains a major challenge. FFS displays using negative liquid crystals have a response time that is 50% or more slower than FFS displays using positive liquid crystals.

[0006] Therefore, improving the response time of negative liquid crystals has become the core issue. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a liquid crystal composition and its applications. The liquid crystal composition provided by this invention possesses excellent properties such as low rotational viscosity, high elastic constant, high optical anisotropy, fast response speed, and good low-temperature miscibility, which can effectively improve the response speed of liquid crystal displays.

[0008] In a first aspect, the present invention provides a liquid crystal composition comprising one or more compounds with the structure shown in general formula I, one or more compounds with the structure shown in general formula II, one or more compounds with the structure shown in general formula III, and one or more compounds with the structure shown in general formula IV.

[0009] in,

[0010] R1 is selected from any one of alkyl groups with 1-7 carbon atoms or alkenyl groups with 2-7 carbon atoms;

[0011] R2 and R3 are each independently selected from any one of alkyl or alkoxy groups with 1 to 7 carbon atoms and alkenyl groups with 2 to 7 carbon atoms;

[0012] R4 and R5 are each independently selected from any one of alkyl or alkoxy groups with 1-7 carbon atoms and alkenyl groups with 2-7 carbon atoms. Selected from

[0013] R6 and R7 are each independently selected from any one of alkyl or alkoxy groups with 1-7 carbon atoms, or alkenyl groups with 2-7 carbon atoms. Selected from

[0014] The numbers 1-7 can be 1, 2, 3, 4, 5, 6, 7, etc., and the numbers 2-7 can be 2, 3, 4, 5, 6, 7, etc.

[0015] The liquid crystal composition provided by this invention possesses excellent properties such as low rotational viscosity, high elastic constant, high optical anisotropy, fast response speed, and good low-temperature miscibility, which can effectively improve the response speed of liquid crystal displays. Specifically:

[0016] Response time and elastic constant K of liquid crystal composition 11The relationship between the liquid crystal and its rotational viscosity γ1 is positive, while the relationship with the rotational viscosity γ1 is negative. This means the response time of a liquid crystal is limited by its rotational viscosity and elastic constant. Reducing the rotational viscosity and increasing the elastic constant of the liquid crystal composition significantly reduces the response time and improves the response speed of the liquid crystal display. In the liquid crystal composition provided by this invention, the compound of general formula I is a dibenzothiophene compound containing a cyclopentene end group, which has a large dielectric constant, a large elastic constant, and a high clearing point. The compound of general formula II is a compound containing dicyclohexane, a bicyclic neutral compound, which has good low-temperature solubility, low rotational viscosity, and a negative dielectric constant, effectively improving the miscibility of the liquid crystal composition. The compound of general formula III is a compound containing a tricyclic negative dielectric constant, which has a large negative dielectric constant and a high clearing point, further increasing the operating temperature of the liquid crystal display and reducing the driving voltage. The compound of general formula IV is a bicyclic negative dielectric constant compound, which has a low clearing point and good low-temperature solubility, effectively reducing the driving voltage. The synergistic effect of these four compounds results in a liquid crystal composition with a small γ1 / K ratio. 11 The ratio can greatly improve the response speed of LCD displays and can be used for fast-response LCD displays in various display modes.

[0017] As a preferred embodiment of the present invention, R1 is selected from any one of straight-chain alkyl groups with 1-5 carbon atoms or straight-chain alkenyl groups with 2-5 carbon atoms.

[0018] As a preferred embodiment of the present invention, R2 is selected from any one of a straight-chain alkyl group with 1-5 carbon atoms or a straight-chain alkenyl group with 2-3 carbon atoms.

[0019] As a preferred embodiment of the present invention, R3 is selected from any one of a straight-chain alkyl group with 1-5 carbon atoms or a straight-chain alkenyl group with 2-5 carbon atoms.

[0020] As a preferred embodiment of the present invention, R4 is selected from any one of straight-chain alkyl groups with 1-5 carbon atoms or straight-chain alkenyl groups with 2-5 carbon atoms.

[0021] As a preferred embodiment of the present invention, R5 is selected from any one of a straight-chain alkyl group with 1-5 carbon atoms or a straight-chain alkoxy group with 1-5 carbon atoms, wherein the O atom is a linking group connected to the benzene ring.

[0022] As a preferred embodiment of the present invention, R6 is selected from any one of straight-chain alkyl groups with 1-5 carbon atoms or straight-chain alkenyl groups with 2-5 carbon atoms.

[0023] As a preferred embodiment of the present invention, R7 is selected from any one of a straight-chain alkyl group with 1-5 carbon atoms or a straight-chain alkoxy group with 1-5 carbon atoms, wherein the O atom is a linking group connected to the benzene ring.

[0024] In this invention, the alkyl group with 1-5 carbon atoms can be methyl, ethyl, propyl, butyl, or pentyl, etc.; the alkoxy group with 1-5 carbon atoms can be methoxy, ethoxy, propoxy, butoxy, or pentoxy; the O atom is a linking group attached to the benzene ring; and the alkenyl group with 2-5 carbon atoms can be vinyl, propenyl, butenyl, or pentenyl, and can be terminal alkenyl or non-terminated alkenyl.

[0025] As a preferred embodiment of the present invention, the compound with the structure shown in general formula I is selected from any one of the following compounds:

[0026] As a preferred embodiment of the present invention, the compound with the structure shown in general formula II is selected from any one of the following compounds:

[0027] As a preferred embodiment of the present invention, the compound with the structure shown in general formula III is selected from any one of the following compounds:

[0028] As a preferred embodiment of the present invention, the compound with the structure shown in general formula IV is selected from any one of the following compounds:

[0029] As a preferred embodiment of the present invention, based on the total mass of the liquid crystal composition as 100%, the content of the compound with the structure shown in general formula I is 1-20%, the content of the compound with the structure shown in general formula II is 1-60%, the content of the compound with the structure shown in general formula III is 1-50%, and the content of the compound with the structure shown in general formula IV is 1-30%.

[0030] The content of the compound with the structure shown in general formula I is 1-20%, for example, it can be 1%, 2%, 5%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, etc.; the content of the compound with the structure shown in general formula II is 1-60%, for example, it can be 1%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, etc.; the content of the compound with the structure shown in general formula III is 1-50%, for example, it can be 1%, 5%, 10%, 20%, 30%, 40%, 50%, etc.; the content of the compound with the structure shown in formula IV is 1-30%, for example, it can be 1%, 5%, 10%, 20%, 30%, etc.

[0031] As a preferred embodiment of the present invention, based on the total mass of the liquid crystal composition as 100%, the content of the compound with the structure shown in general formula I is 1-15%, the content of the compound with the structure shown in general formula II is 20-55%, the content of the compound with the structure shown in general formula III is 10-50%, and the content of the compound with the structure shown in general formula IV is 1-20%.

[0032] As a preferred embodiment of the present invention, based on the total mass of the liquid crystal composition as 100%, the content of the compound with the structure shown in general formula I is 5-15%, the content of the compound with the structure shown in general formula II is 30-55%, the content of the compound with the structure shown in general formula III is 25-50%, and the content of the compound with the structure shown in general formula IV is 5-20%.

[0033] As a preferred embodiment of the present invention, based on the total mass of the liquid crystal composition as 100%, the content of the compound with the structure shown in general formula I is 10-15%, the content of the compound with the structure shown in general formula II is 30-55%, the content of the compound with the structure shown in general formula III is 25-40%, and the content of the compound with the structure shown in general formula IV is 5-15%.

[0034] As a preferred embodiment of the present invention, the liquid crystal composition further includes one or more compounds with the structure shown in general formula V:

[0035] R8 and R9 are each independently selected from any one of alkyl groups with 1 to 7 carbon atoms or alkenyl groups with 2 to 7 carbon atoms.

[0036] The compound with the structure shown in general formula V provided by this invention is a neutral compound containing two rings, which has low rotational viscosity and good low-temperature solubility. Adding it to the liquid crystal composition helps to further reduce the rotational viscosity of the liquid crystal composition in conjunction with the compounds shown in general formulas I-IV.

[0037] As a preferred embodiment of the present invention, R8 is selected from any one of straight-chain alkyl groups with 1-5 carbon atoms or straight-chain alkenyl groups with 2-5 carbon atoms.

[0038] As a preferred embodiment of the present invention, R9 is selected from any one of straight-chain alkyl groups with 1-5 carbon atoms or straight-chain alkenyl groups with 2-5 carbon atoms.

[0039] In this invention, the alkyl group with 1-5 carbon atoms can be methyl, ethyl, propyl, butyl, or pentyl, and the alkenyl group with 2-5 carbon atoms can be vinyl, propenyl, butenyl, or pentenyl. It can be a terminal alkenyl group or a non-terminal alkenyl group.

[0040] As a preferred embodiment of the present invention, the compound with the structure shown in general formula V is selected from any one of the following compounds:

[0041] As a preferred embodiment of the present invention, based on the total mass of the liquid crystal composition as 100%, the content of the compound with the structure shown in general formula V is 0.1-15%, for example 0.1%, 0.5%, 1%, 2%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.2%, 4.5%, 4.8%, 5%, 5.2%, 5.5%, 6%, 8%, 10%, 12%, 14%, 15%, etc.

[0042] When the compound with the structure shown in Formula V is within the content range specified in this invention, it is more beneficial to improve the response time of the liquid crystal display.

[0043] As a preferred embodiment of the present invention, the content of the compound with the structure shown in general formula V is 0.1-10% based on the total mass of the liquid crystal composition as 100%, and more preferably 5-8%.

[0044] As a preferred embodiment of the present invention, the liquid crystal composition further includes one or more compounds with the structure shown in general formula VI:

[0045] Among them, R 10 R 11 Each is independently selected from any one of alkyl or alkoxy groups having 1 to 7 carbon atoms.

[0046] The compound represented by general formula VI provided by this invention is a tetraphenyl compound, which has the effect of improving high-temperature reliability. Its addition to the liquid crystal composition helps to further improve the high-temperature reliability of the liquid crystal composition in conjunction with the compounds represented by general formulas I-V.

[0047] As a preferred technical solution of the present invention, R 10Selected from straight-chain alkyl groups with 2-4 carbon atoms.

[0048] As a preferred technical solution of the present invention, R 11 Selected from straight-chain alkyl groups with 1 to 5 carbon atoms.

[0049] In this invention, the alkyl group with 1-5 carbon atoms can be methyl, ethyl, propyl, butyl, or pentyl.

[0050] As a preferred embodiment of the present invention, the compound with the structure shown in general formula VI is selected from any one of the following compounds:

[0051] As a preferred embodiment of the present invention, based on the total mass of the liquid crystal composition being 100%, the content of the compound with the structure shown in general formula VI is 0.1-10%, for example 0.1%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc.

[0052] As a preferred embodiment of the present invention, based on the total mass of the liquid crystal composition as 100%, the content of the compound with the structure shown in general formula VI is 0.1-5%, preferably 0.1-3%, more preferably 0.1-1%, and most preferably 0.5-1%.

[0053] When the compound with the structure shown in Formula VI of the present invention is within the above-mentioned content limit range, it is more beneficial to improve the response time of the liquid crystal display.

[0054] The present invention does not impose any particular limitation on the preparation method of the liquid crystal composition. Conventional methods can be used to mix two or more compounds for production, such as mixing different components and dissolving them at high temperature. In this method, the liquid crystal composition is dissolved in an organic solvent and mixed, and then the solvent is distilled off under reduced pressure. Alternatively, the liquid crystal composition of the present invention can be prepared according to conventional methods, such as dissolving a component with a smaller content in a major component with a larger content at a higher temperature, or dissolving each component in an organic solvent, such as acetone, chloroform, or methanol, and then mixing the solutions to remove the solvent.

[0055] In a second aspect, the present invention provides the application of the liquid crystal composition described in the first aspect in the field of liquid crystal displays.

[0056] As a preferred embodiment of the present invention, the application of the liquid crystal composition in VA, IPS or FFS mode liquid crystal displays is further preferred in IPS or FFS mode liquid crystal displays.

[0057] The liquid crystal composition provided by this invention can be used in fast-response liquid crystal displays in various display modes. Its use in VA, IPS or FFS mode displays can significantly improve the display effect of liquid crystal displays, and it is especially suitable for IPS and FFS mode liquid crystal displays.

[0058] The technical solution provided by the embodiments of the present invention has the following advantages compared with the prior art:

[0059] 1. The liquid crystal composition provided by the present invention has excellent properties such as low rotational viscosity, high elastic constant, high optical anisotropy, fast response speed and good low-temperature miscibility, which can effectively improve the response speed of liquid crystal displays.

[0060] 2. The liquid crystal composition provided by the present invention can be used in fast-response liquid crystal displays in various display modes. Its use in VA, IPS or FFS mode displays can significantly improve the display effect of the liquid crystal display, and it is especially suitable for IPS and FFS mode liquid crystal displays. Detailed Implementation

[0061] To better understand the above-mentioned objectives, features, and advantages of the present invention, the solutions of the present invention will be further described below. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0062] Many specific details are set forth in the following description in order to provide a full understanding of the invention, but the invention may also be practiced in other ways different from those described herein; obviously, the embodiments in the specification are only some embodiments of the invention, and not all embodiments.

[0063] In the following embodiments, unless otherwise specified, all raw materials used are commercially available. Unless otherwise stated, percentages in this invention are by weight; temperature is measured in °C.

[0064] Examples 1-6

[0065] This embodiment provides a liquid crystal composition and its preparation method. The specific composition of the liquid crystal composition is shown in Table 1.

[0066] Table 1

[0067] The preparation method employs a thermal dissolution method, comprising the following steps:

[0068] Weigh each component compound according to its mass percentage using a balance. There is no specific requirement for the order of weighing and adding the compounds. Usually, the liquid crystal compounds are weighed and mixed in order of their melting points from high to low. The mixture is heated and stirred at 60–100°C to ensure that each component is dissolved evenly. After filtration, the mixture is finally packaged to obtain the liquid crystal composition.

[0069] Examples 7-8

[0070] This embodiment provides a liquid crystal composition and its preparation method. The preparation method is the same as that in Example 1. The specific composition of the liquid crystal composition is shown in Table 2.

[0071] Table 2

[0072] Examples 9-14

[0073] This embodiment provides a liquid crystal composition and its preparation method. The preparation method is the same as that in Example 1. The specific composition of the liquid crystal composition is shown in Table 3.

[0074] Table 3

[0075] Comparative Example 1

[0076] This comparative example provides a liquid crystal composition and its preparation method, which is the same as that in Example 1. The specific composition of the liquid crystal composition is shown in Table 4.

[0077] Table 4

[0078] Comparative Example 2

[0079] This comparative example provides a liquid crystal composition and its preparation method, which is the same as that in Example 1. The specific composition of the liquid crystal composition is shown in Table 5.

[0080] Table 5

[0081] Performance testing

[0082] The liquid crystal compositions prepared in the examples and comparative examples were subjected to performance tests.

[0083] Δn represents optical anisotropy (25℃); Δε represents dielectric anisotropy (25℃, 1000Hz); γ1 represents rotational viscosity (mPa·s, 25℃); Cp represents the clearing point of the liquid crystal composition (℃); K 11 K 33 These represent the elastic constants of development and bending (pN, 25℃), respectively.

[0084] The testing method is as follows:

[0085] Δn: Using a DR-M2 Abbe refractometer, after uniformly coating an alignment agent on the glass surface of the refractometer, liquid crystal is dropped to make the liquid crystal molecules align vertically, and ne and no are measured to obtain Δn.

[0086] Cp: ​​The phase transition temperature obtained by placing the test box filled with liquid crystal into the Instec micro thermal analyzer and heating it at a fixed rate is Cp.

[0087] Δε, K 11 K 33 γ1: The liquid crystal CV curve was measured using an Instec PP1 physical property tester, and Δε and K were calculated. 11 K 33 Parameters such as γ1.

[0088] The results are shown in Table 6:

[0089] Table 6

[0090] As can be seen from the table above, compared with Comparative Example 1, the dielectric anisotropy (Δε), clearing point (Cp), and optical anisotropy (Δn) of the liquid crystal compositions in Examples 1-6 are not significantly different. Under these circumstances, the liquid crystal mixtures provided by the examples have a smaller γ1 / K11. The same is true for Examples 9-14 compared with Comparative Example 2. That is, the liquid crystal compositions provided by the present invention have higher contrast and faster response speed.

[0091] Compared to the examples, Comparative Examples 1 and 2 reduced the amount of the compound shown in Formula I. The examples have a larger elastic constant and a lower rotational viscosity compared to the comparative examples, indicating that the components in the liquid crystal composition provided by the present invention have a synergistic relationship. The compound shown in Formula I is one of the essential components in the liquid crystal composition provided by the present invention.

[0092] As can be seen from the above embodiments, the liquid crystal composition provided by the present invention has a large elastic constant, suitable optical anisotropy, good low-temperature miscibility, low rotational viscosity, and excellent light and thermal stability, which can reduce the response time of liquid crystal displays, thereby solving the problem of slow response speed of liquid crystal displays. 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, and is especially suitable for IPS and FFS liquid crystal display devices.

[0093] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0094] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A liquid crystal composition, characterized by comprising The liquid crystal composition includes one or more compounds with the structure shown in general formula I, one or more compounds with the structure shown in general formula II, one or more compounds with the structure shown in general formula III, and one or more compounds with the structure shown in general formula IV. wherein wherein R1is selected from any one of an alkyl group of 1-7 carbon atoms or an alkenyl group of 2-7 carbon atoms; wherein R2, R3are each independently selected from any one of an alkyl or alkoxy group of 1-7 carbon atoms, an alkenyl group of 2-7 carbon atoms; wherein R4, R5are each independently selected from any one of an alkyl or alkoxy group of 1-7 carbon atoms, an alkenyl group of 2-7 carbon atoms, selected from the group consisting of wherein R6, R7are each independently selected from any one of an alkyl or alkoxy group of 1-7 carbon atoms, an alkenyl group of 2-7 carbon atoms, selected from the group consisting of 2. The liquid crystal composition according to claim 1, characterized by The compound of the structure of Formula I is selected from any one of the following compounds: and / or, the compound of structure II is selected from any one of the following compounds:

3. The liquid crystal composition according to claim 1 or 2, characterized by The compound of the structure of Formula III is selected from any one of the following compounds:

4. The liquid crystal composition according to any one of claims 1 to 3, characterized by, The compound of the structure of Formula IV is selected from any one of the following compounds:

5. The liquid crystal composition according to any one of claims 1 to 4, characterized by, Based on the total mass of the liquid crystal composition as 100%, the content of the compound with the structure shown in general formula I is 1-20%, the content of the compound with the structure shown in general formula II is 1-60%, the content of the compound with the structure shown in general formula III is 1-50%, and the content of the compound with the structure shown in general formula IV is 1-30%. Preferably, based on the total mass of the liquid crystal composition as 100%, the content of the compound with the structure shown in general formula I is 1-15%, the content of the compound with the structure shown in general formula II is 20-55%, the content of the compound with the structure shown in general formula III is 10-50%, and the content of the compound with the structure shown in general formula IV is 1-20%. Preferably, based on the total mass of the liquid crystal composition as 100%, the content of the compound with the structure shown in general formula I is 5-15%, the content of the compound with the structure shown in general formula II is 30-55%, the content of the compound with the structure shown in general formula III is 25-50%, and the content of the compound with the structure shown in general formula IV is 5-20%. Preferably, based on the total mass of the liquid crystal composition as 100%, the content of the compound with the structure shown in general formula I is 10-15%, the content of the compound with the structure shown in general formula II is 30-55%, the content of the compound with the structure shown in general formula III is 25-40%, and the content of the compound with the structure shown in general formula IV is 5-15%.

6. The liquid crystal composition according to any one of claims 1 to 5, characterized by, The liquid crystal composition further comprises one or more compounds having a structure according to Formula V: R8 and R9 are each independently selected from any one of alkyl groups with 1-7 carbon atoms or alkenyl groups with 2-7 carbon atoms; Preferably, the compound of the structure of Formula V is selected from any one of the following compounds:

7. The liquid crystal composition according to claim 6, characterized by Based on the total mass of the liquid crystal composition as 100%, the content of the compound with the structure shown in general formula V is 0.1-15%, preferably 0.1-10%, and more preferably 5-8%.

8. The liquid crystal composition according to any one of claims 1 to 7, characterized by, The liquid crystal composition further comprises one or more compounds having a structure represented by Formula VI: wherein R 10 , R 11 each independently is selected from any one of alkyl or alkoxy of 1-7 carbon atoms; Preferably, the compound of the structure of Formula VI is selected from any one of the following compounds:

9. The liquid crystal composition according to claim 8, characterized by Based on the total mass of the liquid crystal composition as 100%, the content of the compound with the structure shown in general formula VI is 0.1-10%, preferably 0.1-5%, more preferably 0.1-3%, more preferably 0.1-1%, and most preferably 0.5-1%.

10. The use of the liquid crystal composition according to any one of claims 1-9 in the field of liquid crystal displays.

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