Liquid crystal composition with high optical anisotropy

Abstract

The liquid crystal composition provided by the invention has a relatively high optical anisotropy value, and can reduce the box thickness of a display device and improve the response speed; in addition, the liquid crystal composition also has a relatively high dielectric constant, so that the driving voltage of the liquid crystal material is reduced, and the aim of saving energy is fulfilled. The liquid crystal composition is composed of 20%-40% of a compound I1, 5%-15% of a compound I2, 20%-30% of compounds I3-I4, 10%-30% of a compound I5 and 5%-50% of a compound I6.

Description

Technical Field

[0001] This invention relates to the field of liquid crystal materials, and more specifically, to a liquid crystal composition and its application. Background Technology

[0002] In the 1960s, RCA first discovered that electrical stimulation alters the light transmission of liquid crystals, and subsequently applied this property to release liquid crystal display technology. This led to a surge in interest in liquid crystals, which rapidly expanded into various fields. In 1966, DuPont synthesized Kevlar fibers using aramid liquid crystals, marking the beginning of the industrialization of liquid crystal materials. After decades of rapid development, liquid crystal materials, with their unique properties, have been widely applied in display technology, optical storage devices, and solar cells, among many other fields. Research on them extends to chemistry, biology, and information science, making them one of the most sought-after and indispensable new materials in modern society.

[0003] In today's fast-paced life, people's demands for the performance of personal smart devices are two significant aspects: faster speed and greater portability. These demands translate into faster response times and thinner screens in LCD displays. Both of these can be controlled by reducing the cell thickness of the LCD panel; a smaller cell thickness results in a shorter response time and a thinner LCD display. The product of cell thickness and refractive index (called the optical path difference) is predetermined, meaning that with a fixed optical path difference, achieving a smaller cell thickness requires the liquid crystal material to have a high refractive index. Therefore, developing liquid crystal materials with high refractive indexes is crucial for improving the performance of LCD displays. Summary of the Invention

[0004] Purpose of the invention: The main purpose of this invention is to provide a liquid crystal composition with a high optical anisotropy value, which can reduce the cell thickness of display devices and improve the response speed; in addition, the liquid crystal composition also has a high dielectric constant, which is beneficial to reducing the driving voltage of liquid crystal materials, thereby achieving the purpose of energy saving.

[0005] Technical Solution: This invention provides a liquid crystal composition with high optical anisotropy, characterized in that the liquid crystal composition comprises 20%–40% compound I1, 5%–15% compound I2, 20%–30% compounds I3–I4, 10%–30% compound I5, and 5%–50% compound I6. The liquid crystal compounds I1–I6 are as follows:

[0006]

[0007]

[0008] R1 and R1' are each independently selected from alkyl groups having 1 to 7 carbon atoms, alkoxy groups having 1 to 7 carbon atoms, alkenyl groups having 2 to 7 carbon atoms, enalkoxy groups having 2 to 7 carbon atoms, cyclopentyl groups, or cyclopentyl groups substituted with alkyl groups having 1 to 7 carbon atoms, alkoxy groups having 1 to 7 carbon atoms, alkenyl groups having 2 to 7 carbon atoms, or enalkoxy groups having 2 to 7 carbon atoms; wherein the alkyl group, the alkoxy group, the alkenyl group, and the enalkoxy group are straight-chain or branched alkyl groups, alkoxy groups, alkenyl groups, and enalkoxy groups.

[0009] According to another aspect of the present invention, the application of the above-described liquid crystal composition in a liquid crystal display material or a liquid crystal display device is provided.

[0010] Beneficial effects: The liquid crystal composition of the present invention has a high optical anisotropy value, which can reduce the cell thickness of the display device and improve the response speed; in addition, the liquid crystal composition also has a high dielectric constant, which is beneficial to reducing the driving voltage of the liquid crystal material, thereby achieving the purpose of energy saving. Detailed Implementation

[0011] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0012] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0013] To address the aforementioned problems, in a typical embodiment of the present invention, a liquid crystal composition is provided, wherein the liquid crystal composition comprises 20%–40% of compound I1, 5%–15% of compound I2, 20%–30% of compounds I3–I4, 10%–30% of compound I5, and 5%–50% of compound I6. The liquid crystal compounds I1–I6 are as follows:

[0014]

[0015] R1 and R1' are each independently selected from alkyl groups having 1 to 7 carbon atoms, alkoxy groups having 1 to 7 carbon atoms, alkenyl groups having 2 to 7 carbon atoms, enalkoxy groups having 2 to 7 carbon atoms, cyclopentyl groups, or cyclopentyl groups substituted with alkyl groups having 1 to 7 carbon atoms, alkoxy groups having 1 to 7 carbon atoms, alkenyl groups having 2 to 7 carbon atoms, or enalkoxy groups having 2 to 7 carbon atoms; wherein the alkyl group, the alkoxy group, the alkenyl group, and the enalkoxy group are straight-chain or branched alkyl groups, alkoxy groups, alkenyl groups, and enalkoxy groups.

[0016] Compound I1 is a compound with a low melting point, low rotational viscosity, and high optical anisotropy, which is beneficial for adjusting the liquid crystal material to have a lower rotational viscosity and a lower melting point, thereby increasing the response speed and operating temperature range, and also beneficial for increasing the optical anisotropy of the liquid crystal material; Compounds I2 to I5 are compounds with high dielectric constants and high optical anisotropy, which is beneficial for adjusting the liquid crystal material to have a higher dielectric constant, thereby reducing the driving voltage. The combination of multiple components can improve the dielectric constant, lower the melting point, improve the miscibility between components, and also help increase the optical anisotropy of the liquid crystal material; Compound I6 is a compound with a high optical anisotropy, which is beneficial for adjusting the liquid crystal material to have a high optical anisotropy.

[0017] In order to obtain a suitable liquid crystal width, a high dielectric anisotropy value and a low rotational viscosity, which is more conducive to improving the response speed of the liquid crystal material, reducing the threshold voltage, and improving the miscibility of the liquid crystal material, in a preferred embodiment of this application, R1 is selected from alkyl or alkoxy groups having 2 to 5 carbon atoms.

[0018] In another preferred embodiment of this application, R1' is selected from alkyl or alkoxy groups having 2 to 5 carbon atoms.

[0019] The liquid crystal composition of the present invention can be prepared by conventional methods. Typically, the required amount of the component is dissolved in a low amount of the component constituting the main component at a high temperature; alternatively, the solution of each component can be mixed with an organic solvent, such as acetone, chloroform or methanol, and the solvent can be removed again after thorough mixing, for example by distillation.

[0020] In addition to the liquid crystal compounds comprising components I to V described above, the liquid crystal compositions of the present invention may also include other additives available in the art as needed. For example, a stabilizer at a mass content of 0 to 20% and / or a polymerizable compound at a mass content of 0 to 20% and / or a chiral agent at a mass content of 0 to 20% may be added.

[0021] The stabilizer described above is one or more compounds having general formulas S1 to S4:

[0022]

[0023] Wherein, Y1 is selected from H, F, alkyl groups having 1 to 7 carbon atoms, alkoxy groups having 1 to 7 carbon atoms, alkenyl groups having 2 to 7 carbon atoms, enalkoxy groups having 2 to 7 carbon atoms, alkyl halogenates having 1 to 7 carbon atoms, alkoxy halogenates having 1 to 7 carbon atoms, alkenyl halogenates having 2 to 7 carbon atoms, enalkoxy halogenates having 2 to 7 carbon atoms, cyclopentyl groups, or cyclopentyl groups substituted with alkyl groups having 1 to 7 carbon atoms, alkoxy groups having 1 to 7 carbon atoms, alkenyl groups having 2 to 7 carbon atoms, or enalkoxy groups having 2 to 7 carbon atoms; wherein the alkyl group, the alkoxy group, the alkenyl group, and the enalkoxy group are straight-chain or branched alkyl groups, alkoxy groups, alkenyl groups, and enalkoxy groups.

[0024] The polymerizable compound components are as follows:

[0025] in,

[0026]

[0027] —T1 and —T2 represent independently. Or epoxy groups;

[0028] —Q1— and —Q2— each independently represent a single bond or an alkyl group having 1-8 carbon atoms;

[0029] —P1— and —P2— each independently represent a single bond, —O—, —CO—, —COO—, or —OCO—;

[0030] k is 0, 1, or 2;

[0031] When k is 1, —Z1— represents a single bond, —O—, —CO—, —COO—, —OCO—, —CH2O—, —OCH2—, —C2H4—, —CF2O—, —OCF2—, -C≡C-, —CH=CH—,

[0032] When k is 2, —Z1— appears twice in the component. Each appearance of —Z1— independently represents a single bond, —O—, —CO—, —COO—, —OCO—, —CH2O—, —OCH2—, —C2H4—, —CF2O—, —OCF2—, -C≡C-, —CH=CH—,

[0033] express The -CH2- on the cyclohexyl group can be replaced by O, or indicate... The =CH- on the benzene ring can be replaced by N, and the H on the benzene ring can be replaced by F, or represent...

[0034] When k is 1 express The -CH2- on the cyclohexyl group can be replaced by O, or indicate... The =CH- on the benzene ring can be replaced by N, and the H on the benzene ring can be replaced by F, or represent...

[0035] When k is 2, the component includes two Right now It appears twice in the composition.

[0036] Each time it appears, it is independently for The -CH2- group on the cyclohexyl group can be replaced by O, or it can be... The =CH- on the benzene ring can be replaced by N, and the H on the benzene ring can be replaced by F, or...

[0037] The chiral agents mentioned above include, but are not limited to, the following:

[0038]

[0039] The content of liquid crystal compounds in the above liquid crystal composition can be adjusted according to the performance requirements of the liquid crystal material. In a preferred embodiment of the present invention, the liquid crystal composition consists of 20% to 40% of compound I1, 5% to 10% of compound I2, 20% to 30% of compound I3 to I4, 10% to 30% of compound I5, and 20% to 50% of compound I6.

[0040] In yet another typical embodiment of this application, the application of the above-described liquid crystal composition in a liquid crystal display material or a liquid crystal display device is provided.

[0041] The beneficial effects of the present invention will be further illustrated below with reference to embodiments and comparative examples.

[0042] The following examples are for illustrative purposes only and not for limiting the invention. All percentages mentioned in the examples are by mass, and temperatures are expressed in degrees Celsius. The measured physicochemical parameters are expressed as follows: T NI The point of illumination is indicated by Δn; Δn represents optical anisotropy (Δn = n). e -n o 589nm, measured at 25℃); Δε represents dielectric anisotropy (Δε=ε ∥ -ε ⊥ (25℃); k 11 The value represents the elastic modulus of the stretch (measured at 25°C), and T is measured using DSC. NI Δn was measured using an Abbe refractometer; Δε and k were measured using CV. 11 .

[0043] In various embodiments of the present invention, the liquid crystal molecule backbone is named as: phenyl Represented by the letter P; Lateral meta-difluorobenzene Represented by U; the corresponding codes for specific group structures are shown in Table 1:

[0044] Table 1

[0045]

[0046] The side chains of each compound are converted into chemical formulas according to Table 2 below, with the left-side branch denoted by R1 and the right-side branch by R2. The main chain and side chains, as well as the side chains themselves, are separated by a hyphen ("-"). In naming, the main chain comes first, followed by the side chain. For example, Represented as PP-5-CN; Represented as PH1P-5-CN; Represented as UGH1GP-3-2; It is represented as PH1U-3-F.

[0047] Table 2

[0048] codes R1 R2 nm <![CDATA[C n H 2n+1 ]]> <![CDATA[C m H 2m+1 ]]> n-Om <![CDATA[C n H 2n+1 ]]> <![CDATA[OC m H 2m+1 ]]> nO-CN <![CDATA[OC n H 2n+1 ]]> CN nF <![CDATA[C n H 2n+1 ]]> F n-CN <![CDATA[C n H 2n+1 ]]> CN

[0049] Example 1

[0050] The composition and measurement parameters of the liquid crystal composition in Example 1 are shown in Table 3.

[0051] Table 3

[0052]

[0053] Example 2

[0054] The composition and measurement parameters of the liquid crystal composition in Example 2 are shown in Table 4.

[0055] Table 4

[0056]

[0057]

[0058] Example 3

[0059] The composition and measurement parameters of the liquid crystal composition in Example 3 are shown in Table 5.

[0060] Table 5

[0061]

[0062] Example 4

[0063] The composition and measurement parameters of the liquid crystal composition in Example 4 are shown in Table 6.

[0064] Table 6

[0065]

[0066]

[0067] Example 5

[0068] The composition and measurement parameters of the liquid crystal composition in Example 5 are shown in Table 7.

[0069] Table 7

[0070]

[0071] Comparative Example 1

[0072] The composition and measurement parameters of the liquid crystal composition of Comparative Example 1 are shown in Table 11.

[0073] Table 11

[0074]

[0075]

[0076] Compared to Examples 1-5, Comparative Example 1 only contains components I5-I6 and other types of compounds. Comparative test results show that the liquid crystal composition of the present invention has a higher optical anisotropy value, and compared to Comparative Example 1, the optical anisotropy value of the liquid crystal composition of the present invention is higher than 0.30. Therefore, the liquid crystal composition of the present invention is more suitable for display devices with low cell thickness, which is beneficial for improving response speed.

[0077] The above measurement parameters are related to the physicochemical properties of all liquid crystal compounds that make up the liquid crystal medium. The liquid crystal composition of the present invention is mainly used to adjust the liquid crystal parameters of the system.

[0078] While this invention does not exhaustively cover all claimed liquid crystal compositions, those skilled in the art will foresee that, based on the disclosed embodiments described above, other similar materials can be obtained through similar methods without requiring inventive effort, simply by combining their own professional expertise. Due to space limitations, only representative embodiments are listed here.

[0079] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A liquid crystal composition with high optical anisotropy, characterized in that, The liquid crystal composition comprises 20%–40% of compound I1, 5%–15% of compound I2, 20%–30% of compounds I3–I4, 0%–30% of compound I5, and 5%–50% of compound I6. The liquid crystal compounds I1 to I6 are as follows: R1 and R1' are each independently selected from alkyl groups having 1 to 7 carbon atoms, alkoxy groups having 1 to 7 carbon atoms, alkenyl groups having 2 to 7 carbon atoms, enalkoxy groups having 2 to 7 carbon atoms, cyclopentyl groups, or cyclopentyl groups substituted with alkyl groups having 1 to 7 carbon atoms, alkoxy groups having 1 to 7 carbon atoms, alkenyl groups having 2 to 7 carbon atoms, or enalkoxy groups having 2 to 7 carbon atoms; wherein the alkyl group, the alkoxy group, the alkenyl group, and the enalkoxy group are straight-chain or branched alkyl groups, alkoxy groups, alkenyl groups, and enalkoxy groups.

2. The liquid crystal composition with high optical anisotropy according to claim 1, characterized in that, R1 is selected from alkyl or alkoxy groups having 2 to 5 carbon atoms.

3. The liquid crystal composition with high optical anisotropy according to claim 1, characterized in that, The R1 ， Selected from alkyl or alkoxy groups having 2 to 5 carbon atoms.

4. The liquid crystal composition with high optical anisotropy according to claim 1, characterized in that, The liquid crystal composition further comprises a stabilizer in a mass fraction of 0-20%, wherein the stabilizer is one or more compounds having general formulas S1-S4: Wherein, Y1 is selected from H, F, alkyl groups having 1 to 7 carbon atoms, alkoxy groups having 1 to 7 carbon atoms, alkenyl groups having 2 to 7 carbon atoms, enalkoxy groups having 2 to 7 carbon atoms, alkyl halogenates having 1 to 7 carbon atoms, alkoxy halogenates having 1 to 7 carbon atoms, alkenyl halogenates having 2 to 7 carbon atoms, enalkoxy halogenates having 2 to 7 carbon atoms, cyclopentyl groups, or cyclopentyl groups substituted with alkyl groups having 1 to 7 carbon atoms, alkoxy groups having 1 to 7 carbon atoms, alkenyl groups having 2 to 7 carbon atoms, or enalkoxy groups having 2 to 7 carbon atoms; wherein the alkyl group, the alkoxy group, the alkenyl group, and the enalkoxy group are straight-chain or branched alkyl groups, alkoxy groups, alkenyl groups, and enalkoxy groups.

5. A liquid crystal composition with high optical anisotropy according to claim 1, characterized in that, The liquid crystal composition comprises 20%–40% of compound I1, 5%–10% of compound I2, 20%–30% of compound I3–I4, 10%–30% of compound I5, and 20%–50% of compound I6.

6. A liquid crystal composition with high optical anisotropy according to claim 1, characterized in that, The liquid crystal composition also contains a chiral agent in a mass fraction of 0-20%.

7. The use of the liquid crystal composition according to any one of claims 1 to 6 in a liquid crystal display material or a liquid crystal display device.

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