Liquid crystal composition and use thereof

Abstract

The application belongs to the technical field of liquid crystal display, and discloses a liquid crystal composition, which comprises a compound shown in formula I and a compound shown in formula II. The liquid crystal composition has a high clearing point, a large K value, good low-temperature mutual solubility and good reliability, and can effectively improve the residual image of the liquid crystal composition. The application further discloses a liquid crystal display element or a liquid crystal display comprising the liquid crystal composition.

Description

Technical Field

[0001] This invention belongs to the field of liquid crystal display technology. More specifically, it relates to a liquid crystal composition and its application. Background Technology

[0002] With the development of technology and the increasing electronic use of medical devices, the displays required for these devices have been further developed. However, with prolonged use, the circuitry inside the screen generates a lot of heat, which accelerates the aging of the display. Moreover, the clarity of the display directly affects the doctor's diagnosis. Therefore, "accuracy" and "clarity" are essential attributes of medical display panels.

[0003] The elastic constant of liquid crystals is a physical quantity that describes the elastic deformation of liquid crystal molecules, and includes the developmental elastic constant K. 11 Torsional elastic constant K 22 Flexural elastic constant K 33 The larger the K value, the less likely the liquid crystal molecules are to undergo elastic deformation. We use K... 平均 K is used to characterize the average elastic coefficient of liquid crystal molecules. 平均 =(K 11 +K 22 +K 33 ) / 3. In LCD displays, K 平均 The size is related to the ordered arrangement of liquid crystal molecules, K 平均 Liquid crystals with higher contrast ratios have more ordered molecular arrangements, making them less susceptible to light transmission when no voltage is applied, resulting in a better dark state. When voltage is applied, light transmits more easily, resulting in a brighter bright state. The contrast ratio of an LCD monitor is calculated as brightness / darkness. Therefore, a darker dark state and a brighter bright state effectively improve the contrast ratio of the LCD monitor. Higher contrast ratios result in higher screen clarity.

[0004] Therefore, developing high-contrast, high-reliability liquid crystal compositions is a pressing technical problem that needs to be solved. Summary of the Invention

[0005] The first objective of this invention is to provide a liquid crystal composition that combines a large K value, high contrast, good reliability, and good low-temperature performance.

[0006] A second objective of the present invention is to provide a liquid crystal display element or liquid crystal display comprising the liquid crystal composition.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] This invention provides a liquid crystal composition comprising one or more compounds of Formula I and one or more compounds of Formula II:

[0009]

[0010] in,

[0011] R represents an alkyl group with 1-10 carbon atoms, a fluorinated alkyl group with 1-10 carbon atoms, an alkenyl group with 2-10 carbon atoms, or a fluorinated alkenyl group with 2-10 carbon atoms.

[0012] R1 and R2 each independently represent an alkyl group with 1-10 carbon atoms, an alkoxy group with 1-10 carbon atoms, or an alkenyl group with 2-10 carbon atoms;

[0013] X represents O or S.

[0014] Invention Effects

[0015] The liquid crystal composition of the present invention has a large K value, high contrast, high reliability and good low temperature performance, which has significant advantages in medical high contrast and high reliability displays, and can be used to develop high reliability and high contrast liquid crystal display elements or liquid crystal displays. Detailed Implementation

[0016] This invention provides a liquid crystal composition comprising one or more compounds of Formula I and one or more compounds of Formula II:

[0017]

[0018] in,

[0019] R represents an alkyl group with 1-10 carbon atoms, a fluorinated alkyl group with 1-10 carbon atoms, an alkenyl group with 2-10 carbon atoms, or a fluorinated alkenyl group with 2-10 carbon atoms.

[0020] R1 and R2 each independently represent an alkyl group with 1-10 carbon atoms, an alkoxy group with 1-10 carbon atoms, or an alkenyl group with 2-10 carbon atoms;

[0021] X represents O or S.

[0022] The liquid crystal composition of the present invention has a large K value, high contrast and high reliability as well as good low temperature performance.

[0023] Preferably, the liquid crystal composition of the present invention comprises a compound represented by Formula I selected from the group consisting of compounds represented by Formulas I-1 to I-16 below:

[0024]

[0025]

[0026]

[0027] Preferably, the liquid crystal composition of the present invention comprises at least one compound selected from the compounds of formula I-1, I-2, I-9, and I-10, and the mass percentage is 7%-15%.

[0028] Preferably, in the liquid crystal composition of the present invention, the compound represented by Formula II is selected from the group consisting of compounds represented by Formulas II-1 to II-6:

[0029]

[0030] The liquid crystal composition provided by this invention has a synergistic effect, and can achieve a larger K value while maintaining dielectric anisotropy and the same refractive index. 平均 =(K 11 +K 22 +K 33 ) / 3, with high contrast, good reliability, can be used for a long time and at a high frequency, and has a large solubility. In particular, it has good low temperature resistance and can be used for a long time in cold environments.

[0031] Preferably, the liquid crystal composition of the present invention further comprises one or more compounds of formula III:

[0032]

[0033] in,

[0034] R3 and R4 each independently represent an alkyl group with 1-10 carbon atoms, an alkoxy group with 1-10 carbon atoms, or an alkenyl group with 2-10 carbon atoms;

[0035] Each can be independently represented as 1,4-phenylene or 1,4-cyclohexylene.

[0036] Preferably, in the liquid crystal composition of the present invention, the compound represented by Formula III is selected from the group consisting of compounds represented by Formulas III-1 to III-13:

[0037]

[0038] Preferably, the liquid crystal composition of the present invention contains 15-55% by mass of the compound represented by Formula III.

[0039] Preferably, the liquid crystal composition of the present invention further comprises one or more compounds represented by Formula IV:

[0040]

[0041] in,

[0042] R5 and R6 each independently represent an alkyl group with 1-10 carbon atoms, an alkoxy group with 1-10 carbon atoms, or an alkenyl group with 2-10 carbon atoms;

[0043] F1, F2, F3, and F4 each independently represent H or F, and at least two of F1 to F4 represent F.

[0044] Preferably, in the liquid crystal composition of the present invention, the compound represented by Formula IV is selected from the group consisting of compounds represented by Formulas IV-1 to IV-7:

[0045]

[0046]

[0047] Preferably, the liquid crystal composition of the present invention comprises at least 3% by mass of the compound shown in Formula IV-3.

[0048] Preferably, the liquid crystal composition of the present invention further comprises one or more compounds represented by Formula V:

[0049]

[0050] in,

[0051] R7 and R8 each independently represent an alkyl group with 1-10 carbon atoms, an alkoxy group with 1-10 carbon atoms, or an alkenyl group with 2-10 carbon atoms.

[0052] Preferably, in the liquid crystal composition of the present invention, the compound represented by Formula V is selected from the group consisting of compounds represented by Formulas V-1 to V-3:

[0053]

[0054] Preferably, in the liquid crystal composition of the present invention, the mass percentage of the compound represented by the aforementioned formula V is 5-25%.

[0055] Preferably, the liquid crystal composition of the present invention comprises at least one of the compounds shown in Formula V-4 and / or V-5, and the mass percentage is 6.5%-15.5%.

[0056] Preferably, the liquid crystal composition of the present invention further comprises one or more compounds represented by formula VI:

[0057]

[0058] in,

[0059] R9 and R 10 Each can independently represent an alkyl group having 1-10 carbon atoms, an alkoxy group having 1-10 carbon atoms, or an alkenyl group having 2-10 carbon atoms;

[0060] It represents 1,4-phenylene or 1,4-cyclohexylene.

[0061] Preferably, in the liquid crystal composition of the present invention, the compound represented by Formula VI is selected from the group consisting of compounds represented by Formulas VI-1 to VI-8:

[0062]

[0063] Preferably, the liquid crystal composition of the present invention comprises at least the compound shown in Formula VI-7, and the mass percentage is 5%-10%.

[0064] Preferably, the liquid crystal composition of the present invention further comprises one or more compounds represented by formula VII:

[0065]

[0066] in,

[0067] R 11 and R 12 Each of these can be independently represented as an alkyl group having 1-10 carbon atoms, a fluorinated alkyl group having 1-10 carbon atoms, an alkoxy group having 1-10 carbon atoms, a fluorinated alkoxy group having 1-10 carbon atoms, an alkenyl group having 2-10 carbon atoms, a fluorinated alkenyl group having 2-10 carbon atoms, an alkenyl group having 3-8 carbon atoms, or a fluorinated alkenyl group having 3-8 carbon atoms.

[0068] It represents 1,4-cyclohexeneyl or 1,4-cyclohexeneyl.

[0069] Preferably, in the liquid crystal composition of the present invention, the compound represented by formula VII is selected from the group consisting of compounds represented by formulas VII-1 to VII-10:

[0070]

[0071]

[0072] Preferably, various functional dopants may be added to the liquid crystal compound; the mass percentage content of the dopants in the liquid crystal composition is preferably between 0.01% and 1%.

[0073] Preferably, the dopant is mainly an antioxidant, a light stabilizer, etc.

[0074] Preferably, the antioxidant is selected from one or more compounds shown in the following structural formulas:

[0075]

[0076] Where S represents an integer from 1 to 10.

[0077] Preferably, the light stabilizer is

[0078]

[0079] in,

[0080] S represents an integer from 1 to 10.

[0081] [Liquid crystal display element or liquid crystal display]

[0082] The present invention also provides a liquid crystal display element or liquid crystal display comprising the above-described liquid crystal composition.

[0083] Preferably, the aforementioned liquid crystal display element can be an active matrix addressing liquid crystal display element or a passive matrix display element; the liquid crystal display device can be an active matrix addressing liquid crystal display or a passive matrix display.

[0084] Preferably, the active matrix addressing liquid crystal display element is an FFS-TFT liquid crystal display element or a liquid crystal display.

[0085] The liquid crystal display element and liquid crystal display of the present invention contain the liquid crystal composition of the present invention, and can be used to develop liquid crystal display elements or liquid crystal displays with low drive, high reliability, and high contrast, and are particularly suitable for medical devices.

[0086] Example

[0087] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments, further clarifies the invention. Those skilled in the art should understand that the specific descriptions below are illustrative rather than restrictive, and should not be construed as limiting the scope of protection of the present invention.

[0088] In this invention, the preparation methods are all conventional unless otherwise specified, and the raw materials used are all available from publicly available commercial sources unless otherwise specified. Percentages refer to mass percentages, and temperatures are in degrees Celsius (°C). The specific meanings of other symbols and test conditions are as follows:

[0089] Cp represents the liquid crystal clearing point (°C), measured by DSC quantitative method;

[0090] SN represents the melting point (°C) of the crystalline to nematic phase of the liquid crystal;

[0091] Δn represents optical anisotropy, Δn = ne -n o , where n o Let n be the refractive index of ordinary light. e The refractive index of unusual light was measured at 25±2℃, 589nm, using an Abbe refractometer.

[0092] Δε represents dielectric anisotropy, Δε = ε ∥ -ε ⊥ , where ε ∥ ε is the dielectric constant parallel to the molecular axis. ⊥ The dielectric constant is perpendicular to the molecular axis. The test conditions are 25±0.5℃, 20-micron antiparallel cell, and INSTEC:ALCT-IR1 test.

[0093] γ1 represents rotational viscosity (mPa·s), and the test conditions are 25±0.5℃, 20-micron antiparallel cell, INSTEC:ALCT-IR1 test;

[0094] K 11 K is the elastic constant of the development. 33 The bending elastic constant was determined under the following test conditions: 25℃, INSTEC:ALCT-IR1, and a 20-micron antiparallel box.

[0095] VHR represents the voltage hold-up rate (%). The test conditions were 60±1℃, ±5V, pulse width 10ms, and voltage hold-up time 1.667ms. The test equipment was a TOYO Model 6254 LCD performance comprehensive tester.

[0096] CR represents the contrast ratio of a liquid crystal display (LCD). Contrast ratio is the ratio of the bright state of the LCD to the dark state. Test conditions: 25±1℃, normal driving voltage, and 64Hz. Test equipment: DMS505.

[0097] Image retention: Image retention in liquid crystal displays is evaluated by visual inspection of the residual level of the inherent pattern when the entire screen is displayed uniformly after displaying a specified fixed pattern within the display area for 1000 hours. The evaluation is based on the following four levels:

[0098] ◎No residue

[0099] ○ A very small amount of residue remains, which is within an acceptable level.

[0100] △ Residue exists, at an unacceptable level.

[0101] × Residue remains, quite poor quality.

[0102] Low-temperature observation conditions: Pour 1g of liquid crystal into a 5ml clean glass vial, seal it and place it in a -40℃ low-temperature freezer. Observe whether crystal precipitation occurs in the liquid crystal after 960h.

[0103] The liquid crystal monomer structure in the embodiments of the present invention is represented by code. The code representation methods of liquid crystal ring structure, end group and linking group are shown in Table 1 and Table 2 below.

[0104] Table 1. Corresponding codes for ring structures

[0105]

[0106] Table 2. Correspondence codes between end groups and linking groups

[0107]

[0108]

[0109] For example:

[0110] Its code is CC-Cp-V1

[0111] Its code is COY-3-O2

[0112] Its code is CCOY-5-O2

[0113] Its code is Sb-Cpr3O-O3

[0114] Its code is Sc-Cpr3O-O3

[0115] Its code is Sb-Cpr3O-O3F

[0116] Its code is Sc-CpO-O3

[0117] Its code is Sb-CpO-O3

[0118] Its code is PGP-Cpr1-2.

[0119] The present invention will be described below using specific embodiments:

[0120] The liquid crystal composition provided in this embodiment of the invention is prepared by weighing each type of monomer according to the designed mass percentage, stirring them together in a beaker, heating to a clearing point, maintaining for 30 minutes, cooling to room temperature, and then testing various parameters under test conditions.

[0121] The present invention will be described below using specific embodiments.

[0122] Example 1

[0123] The formulations and corresponding properties of the liquid crystal compositions are shown in Table 3 below.

[0124] Table 3 Formulation and corresponding properties of the liquid crystal composition in Example 1

[0125]

[0126]

[0127] Example 2

[0128] The formulations and corresponding properties of the liquid crystal compositions are shown in Table 4 below.

[0129] Table 4 Formulation and corresponding properties of the liquid crystal composition in Example 2

[0130]

[0131] Example 3

[0132] The formulations and corresponding properties of the liquid crystal compositions are shown in Table 5 below.

[0133] Table 5. Formulation and corresponding properties of the liquid crystal composition in Example 3.

[0134]

[0135]

[0136] Example 4

[0137] The formulations and corresponding properties of the liquid crystal compositions are shown in Table 6 below.

[0138] Table 6. Formulation and corresponding properties of the liquid crystal composition in Example 4.

[0139]

[0140]

[0141] Example 5

[0142] The formulations and corresponding properties of the liquid crystal compositions are shown in Table 7 below.

[0143] Table 7 Formulation and corresponding properties of the liquid crystal composition in Example 5

[0144]

[0145] Example 6

[0146] The formulations and corresponding properties of the liquid crystal compositions are shown in Table 8 below.

[0147] Table 8. Formulation and corresponding properties of the liquid crystal composition in Example 6

[0148]

[0149]

[0150] Example 7

[0151] The formulations and corresponding properties of the liquid crystal compositions are shown in Table 9 below.

[0152] Table 9 Formulation and corresponding properties of the liquid crystal composition in Example 7

[0153]

[0154]

[0155] The monomers used in the comparative proportions are as follows:

[0156]

[0157] Comparative Example 1

[0158] The formulations and corresponding properties of the liquid crystal compositions are shown in Table 10 below.

[0159] Table 10. Formulations and corresponding properties of the liquid crystal compositions in Comparative Example 1

[0160]

[0161]

[0162] Comparative Example 2

[0163] The formulations and corresponding properties of the liquid crystal compositions are shown in Table 11 below.

[0164] Table 11. Formulations and corresponding properties of the liquid crystal compositions in Comparative Example 2

[0165]

[0166] Comparative Example 3

[0167] The formulations and corresponding properties of the liquid crystal compositions are shown in Table 12 below.

[0168] Table 12 Formulations and corresponding properties of the liquid crystal compositions in Comparative Example 3

[0169]

[0170]

[0171] Comparative Example 4

[0172] The formulations and corresponding properties of the liquid crystal compositions are shown in Table 13 below.

[0173] Table 13. Formulations and corresponding properties of the liquid crystal compositions in Comparative Example 4

[0174]

[0175]

[0176] Comparative Example 5

[0177] The formulations and corresponding properties of the liquid crystal compositions are shown in Table 14 below.

[0178] Table 14. Formulations and corresponding properties of the liquid crystal compositions in Comparative Example 5

[0179]

[0180] Comparative Example 6

[0181] The formulations and corresponding properties of the liquid crystal compositions are shown in Table 15 below.

[0182] Table 15. Formulations and corresponding properties of the liquid crystal compositions in Comparative Example 6

[0183]

[0184]

[0185] Comparative Example 7

[0186] The formulations and corresponding properties of the liquid crystal compositions are shown in Table 16 below.

[0187] Table 16. Formulations and corresponding properties of the liquid crystal compositions in Comparative Example 7

[0188]

[0189]

[0190] Table 17 Comparison of crystallization, image retention, and contrast (CR) between Examples 1-7 and Comparative Examples 1-7

[0191] Experiment number <![CDATA[K 平均 ]]> Contrast Ratio CR afterimage Place at -40℃ for 960 hours Example 1 19.8 2371:1 ◎ No crystals precipitated Example 2 19.7 2367:1 ◎ No crystals precipitated Example 3 19.5 2358:1 ◎ No crystals precipitated Example 4 19.6 2360:1 ◎ No crystals precipitated Example 5 19.6 2360:1 ◎ No crystals precipitated Example 6 19.7 2367:1 ◎ No crystals precipitated Example 7 19.6 2360:1 ◎ No crystals precipitated Comparative Example 1 15.6 1641:1 ○ No crystals precipitated Comparative Example 2 16.0 1650:1 △ Crystals precipitate Comparative Example 3 17.9 1700:1 × Crystals precipitate Comparative Example 4 15.2 1640:1 × Crystals precipitate Comparative Example 5 15.5 1641:1 × Crystals precipitate Comparative Example 6 16.1 1650:1 × Crystals precipitate Comparative Example 7 13.6 1300:1 × Crystals precipitate

[0192] The elastic constant of liquid crystals is a physical quantity that describes the elastic deformation of liquid crystal molecules, and includes the developmental elastic constant K. 11 Torsional elastic constant K 22 Flexural elastic constant K 33 The larger the K value, the less likely the liquid crystal molecules are to undergo elastic deformation. We use K... 平均 K is used to characterize the elastic modulus of liquid crystal molecules. 平均=(K 11 +K 22 +K 33 ) / 3. In LCD displays, K 平均 The size is related to the ordered arrangement of liquid crystal molecules, K 平均 Liquid crystals with higher contrast ratios have more ordered molecular arrangements, resulting in a darker dark state when no power is applied, effectively improving the contrast ratio of the LCD monitor. The contrast ratio of an LCD monitor is calculated as brightness / darkness; a higher contrast ratio means clearer display.

[0193] Table 18 Comparison of VHR conditions between Examples 1-7 and Comparative Examples 1-7

[0194]

[0195]

[0196] Backlight test: The liquid crystal composition is poured into the corresponding test box, sealed, and placed on a backlight with a light intensity of 25000 nits for backlight aging test. After aging for 500h and 1000h respectively, VHR test is performed.

[0197] The smaller the change in VHR data after aging tests compared to the initial VHR data, the stronger the resistance of the liquid crystal composition to external environmental damage, and therefore the higher the reliability of the liquid crystal composition.

[0198] This invention only replaces embodiment 7; other embodiments can achieve the same technical effect using the same comparative method. That is, the technical solution provided by this invention has suitable dielectric anisotropy, optical anisotropy, and a large elastic constant K. 平均 With its high contrast, good low-temperature miscibility, and good reliability, it can be used for wide-temperature display and high-contrast liquid crystal display elements or liquid crystal displays, especially suitable for high-contrast liquid crystal display elements or liquid crystal displays for medical devices.

[0199] The above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A liquid crystal composition, characterized by comprising The liquid crystal composition comprises one or more compounds selected from the group consisting of compounds represented by formulae I-1, I-2, I-9, and I-10, wherein the content of any one component is 7 to 15%, one or more compounds represented by formulae II-1 to II-6, and a compound represented by formula III in an amount of 15 to 55% by mass: wherein, R3, R4 each independently represent an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms; each independently represents 1,4-phenylene or 1,4-cyclohexylene.

2. The liquid crystal composition according to claim 1, characterized by The liquid crystal composition comprises one or more compounds represented by formula IV: wherein, R5, R6 each independently represent an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms; F1, F2, F3, F4 each independently represent H or F, and at least two of F1 to F4 represent F.

3. The liquid crystal composition according to claim 2, characterized by The liquid crystal composition further comprises one or more compounds represented by formula V: wherein, R7, R8 each independently represent an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms.

4. The liquid crystal composition according to claim 3, characterized by The liquid crystal composition further comprises one or more compounds represented by formula VI: wherein, R9and R 10 each independently represents an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms; represents 1,4-phenylene or 1,4-cyclohexylene.

5. The liquid crystal composition according to claim 4, characterized by The liquid crystal composition further comprises one or more compounds represented by formula VII: wherein, R 11 and R 12 each independently represents an alkyl group having 1 to 10 carbon atoms, a fluorine-substituted alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a fluorine-substituted alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, a fluorine-substituted alkenyl group having 2 to 10 carbon atoms, an alkenyloxy group having 3 to 8 carbon atoms, or a fluorine-substituted alkenyloxy group having 3 to 8 carbon atoms; represents 1,4-cyclohexenylene or 1,4-cyclohexylene.

6. A liquid crystal display element comprising the liquid crystal composition according to any one of claims 1 to 5, which is an active matrix display element or a passive matrix display element.

7. A liquid crystal display comprising the liquid crystal composition according to any one of claims 1 to 5, which is an active matrix display or a passive matrix display.

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