Liquid crystal composition containing polymerizable compound and application thereof

Abstract

The invention belongs to the technical field of liquid crystal materials, and particularly relates to a cholesteric liquid crystal composition and a liquid crystal display element or a liquid crystal display containing the cholesteric liquid crystal composition. The invention discloses a cholesteric liquid crystal composition which comprises a liquid crystal component and an additive, the additive comprises at least one polymerizable compound, and the polymerizable compound is selected from one or more compounds shown in a formula I, a formula II and a formula III as the additive. The cholesteric liquid crystal composition provided by the invention has low power consumption current and has an excellent anti-pressing effect after polymerization, and a liquid crystal display component obtained by thermally polymerizing the cholesteric liquid crystal containing the additive has good anti-pressing performance and can be applied to the field of optical devices such as liquid crystal electronic books and the like. The problem that the cholesteric liquid crystal display component is poor in pressing resistance can be effectively solved. # imgabs0 #

Description

Technical Field

[0001] The present invention belongs to the technical field of bistable liquid crystal display, and in particular relates to a cholesteric liquid crystal composition and a liquid crystal display element or a liquid crystal display containing the cholesteric liquid crystal composition. Background Art

[0002] Cholesteric liquid crystal has the advantages of high contrast, zero power consumption for displaying content, and no need for polarizers. Therefore, it is widely used in e-books, electronic labels, display panels and other fields.

[0003] The planar state (P) and focal conic state (Fc) of cholesteric liquid crystal are stable and can remain stable for a long time, thus having bistability. Cholesteric liquid crystal has Bragg reflection in the planar state. The reflection wavelength (λ) is determined by the average refractive index (n) of the liquid crystal composition and the chiral pitch (P), λ = n 平均 ×P. When the refractive index of the liquid crystal composition is fixed, the chiral pitch P can be adjusted by increasing or decreasing the amount of chiral compounds, thereby obtaining different colors of reflected wavelengths. Under the same pitch, the wavelength width (Δλ) of the reflected light is proportional to the refractive index anisotropy (Δn=ne-no) of the liquid crystal. In order to achieve high brightness of reflection, a liquid crystal composition with a large Δn is required.

[0004] The planar state energy of cholesteric liquid crystal is the lowest, and the focal conic state energy is high. The focal conic state of cholesteric liquid crystal is easily transformed into the planar state under external pressure, which makes the cholesteric liquid crystal have the disadvantage of not being able to withstand pressure. In order to improve the pressure resistance of cholesteric liquid crystal, a thick glass or acrylic cover is usually added to the outside of the cholesteric liquid crystal screen to play a protective and pressure-resistant role, but this method has problems such as heavy quality and serious loss of optical reflectivity, and cannot completely solve the problem of cholesteric liquid crystal not being able to withstand pressure. In addition, there is also a method in the prior art to make a sealing frame by screen printing to improve the pressure resistance of cholesteric liquid crystal electronic paper, but this method requires high temperature production, the production process is difficult, and the biggest problem is that the viscosity of cholesteric liquid crystal is very large, and the numerous sealing frames in the liquid crystal box are easy to cause uneven diffusion of liquid crystal during crystal filling, and vacuum bubbles are easily formed, resulting in a low yield of the liquid crystal screen.

[0005] Therefore, how to solve the above-mentioned technical defects has become a technical problem that needs to be solved urgently. Summary of the invention

[0006] In view of the above technical problems, the present invention provides a cholesteric liquid crystal composition and a liquid crystal display element or liquid crystal display containing the cholesteric liquid crystal composition. The cholesteric liquid crystal composition provided by the present invention contains a specific additive, has good anti-pressing performance and low power consumption after thermal polymerization. The liquid crystal display element made of the cholesteric liquid crystal composition of the present invention can be used in the field of optical devices such as liquid crystal e-books, and can effectively improve the problem of anti-pressing difference of cholesteric liquid crystal display elements.

[0007] The cholesteric liquid crystal composition provided by the present invention comprises a liquid crystal component and an additive, wherein the additive comprises at least one polymerizable compound, and the polymerizable compound is selected from one or more compounds represented by formula I, compounds represented by formula II, and compounds represented by formula III.

[0008]

[0009] in,

[0010] R1 and R2 each independently represent H, F, an alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms substituted with fluorine, an alkoxy group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms substituted with fluorine, an alkenyl group having 2 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms substituted with fluorine, an ester group having 2 to 6 carbon atoms, an ester group having 2 to 6 carbon atoms, an ester group having 2 to 6 carbon atoms, an alkenyloxy group having 3 to 8 carbon atoms, or an alkenyloxy group having 3 to 8 carbon atoms substituted with fluorine, and any one or more -CH2- groups represented by R1 are optionally replaced by cyclopentylene, cyclobutylene or cyclopropylene;

[0011] X and Z each independently represent -O-, -COO-, -CH2-, -CH2O- or -C2H4-;

[0012] X1, X4, X7, X 10 Each independently represents H, F or methyl;

[0013] X2, X3, X5, X6, X8, X9, X 11 , X 12 Each independently represents H or F;

[0014] m, n, and a each independently represent 0, 1, or 2;

[0015] Each independently expresses

[0016] Each independently expresses

[0017] A second object of the present invention is to provide a liquid crystal display element, which comprises the aforementioned cholesteric liquid crystal composition, and the liquid crystal display element is an active matrix addressing display element or a passive matrix addressing display element.

[0018] The third object of the present invention is to provide a liquid crystal display, which comprises the above-mentioned cholesteric liquid crystal composition, and the liquid crystal display is an active matrix addressing display or a passive matrix addressing display.

[0019] Effects of the Invention

[0020] The cholesteric liquid crystal composition provided by the present invention has low power consumption current, has excellent anti-pressing effect and excellent reliability performance after polymerization, and the liquid crystal display component containing the cholesteric liquid crystal additive of the present invention after thermal polymerization has good anti-pressing performance and can be used in the field of optical devices such as liquid crystal e-books. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 :The effect of pressing the cholesteric liquid crystal sample containing additives

[0022] Figure 2 :The effect of the additive-free cholesteric liquid crystal sample after pressing

[0023] No. 1: Cholesteric display element with liquid crystal additives

[0024] No. ②: Press the test pen tip

[0025] No. ③: Fine traces left after pressing

[0026] No. 4: Cholesteric display element without liquid crystal additives

[0027] No. 5: Thick handwriting left after pressing DETAILED DESCRIPTION

[0028] The cholesteric liquid crystal composition provided by the present invention comprises components and additives, wherein the additives comprise at least one polymerizable compound, and the polymerizable compound is selected from one or more compounds represented by formula I, compounds represented by formula II, and compounds represented by formula III.

[0029]

[0030] in,

[0031] R1 and R2 each independently represent H, F, an alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms substituted with fluorine, an alkoxy group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms substituted with fluorine, an alkenyl group having 2 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms substituted with fluorine, an ester group having 2 to 6 carbon atoms, an ester group having 2 to 6 carbon atoms, an ester group having 2 to 6 carbon atoms, an alkenyloxy group having 3 to 8 carbon atoms, or an alkenyloxy group having 3 to 8 carbon atoms substituted with fluorine, and any one or more -CH2- groups represented by R1 are optionally replaced by cyclopentylene, cyclobutylene or cyclopropylene;

[0032] X and Z each independently represent -O-, -COO-, -CH2-, -CH2O- or -C2H4-;

[0033] X1, X4, X7, X 10 Each independently represents H, F or methyl;

[0034] X2, X3, X5, X6, X8, X9, X 11 , X 12 Each independently represents H or F;

[0035] m, n, and a each independently represent 0, 1, or 2;

[0036] Each independently expresses

[0037] Each independently expresses

[0038] In the cholesteric liquid crystal composition of the present invention, preferably, the compound represented by the aforementioned formula I is selected from at least one compound represented by the following formulas I-1 to I-16,

[0039]

[0040]

[0041] In the cholesteric liquid crystal composition of the present invention, it is further preferred that the compound represented by the aforementioned formula I is selected from at least one compound represented by formulas I-1 to I-8.

[0042] In the cholesteric liquid crystal composition of the present invention, it is further preferred that the mass of the compound represented by the aforementioned formula I is 0-16% of the mass of the liquid crystal component, and further preferably 0-10%.

[0043] In the cholesteric liquid crystal composition of the present invention, preferably, the compound represented by the aforementioned formula II is selected from at least one compound represented by the following formulas II-1 to II-16,

[0044]

[0045]

[0046] R1 independently represents H, F, an alkyl group having 1-6 carbon atoms, an alkyl group having 1-6 carbon atoms substituted with fluorine, an alkoxy group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms substituted with fluorine, an alkenyl group having 2-6 carbon atoms, an alkenyl group having 2-6 carbon atoms substituted with fluorine, an ester group having 2-6 carbon atoms, an ester group having 2-6 carbon atoms, an ester group having 2-6 carbon atoms, an alkenyloxy group having 3-8 carbon atoms, or an alkenyloxy group having 3-8 carbon atoms substituted with fluorine, and any one or more -CH2- in the group represented by R1 is optionally replaced by a cyclopentylene, a cyclobutylene or a cyclopropyleneene.

[0047] In the cholesteric liquid crystal composition of the present invention, it is further preferred that the compound represented by the aforementioned formula II is selected from at least one compound represented by formula II-1, II-2, II-9, II-10 and II-11; and even more preferably, it is selected from at least one compound represented by formula II-2, II-10 and II-11.

[0048] In the cholesteric liquid crystal composition of the present invention, it is further preferred that the mass of the compound represented by the aforementioned formula II is 0-12% of the mass of the liquid crystal component, and further preferably 0-6%.

[0049] In the cholesteric liquid crystal composition of the present invention, preferably, the compound represented by the aforementioned formula III is selected from at least one compound represented by the following formulas III-1 to III-9,

[0050]

[0051] In the cholesteric liquid crystal composition of the present invention, it is further preferred that the compound represented by the aforementioned formula III is selected from at least one compound represented by formula III-3, III-4, and III-5.

[0052] In the cholesteric liquid crystal composition of the present invention, it is further preferred that the mass of the compound represented by the aforementioned formula III is 0-12% of the mass of the liquid crystal component, and further preferably 0-6%.

[0053] In the cholesteric liquid crystal composition of the present invention, preferably, the liquid crystal component comprises one or more compounds represented by formula IV,

[0054]

[0055] in,

[0056] R3 independently represents H, F, an alkyl group having 1 to 15 carbon atoms, an alkyl group having 1 to 15 carbon atoms substituted with fluorine, an alkoxy group having 1 to 15 carbon atoms, an alkoxy group having 1 to 15 carbon atoms substituted with fluorine, an alkenyl group having 2 to 15 carbon atoms, an alkenyl group having 2 to 15 carbon atoms substituted with fluorine, an ester group having 2 to 15 carbon atoms, an ester group having 2 to 15 carbon atoms, an ester group having 2 to 15 carbon atoms substituted with fluorine, an alkenyloxy group having 3 to 15 carbon atoms, or an alkenyloxy group having 3 to 15 carbon atoms substituted with fluorine, and any one or more -CH2- groups represented by R3 are optionally replaced by cyclopentylene, cyclobutylene or cyclopropylene;

[0057] Z1 represents a single bond, -C≡C-, COO or -CF2O-;

[0058] X 13 represents F, CN, an alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms substituted with fluorine, an alkoxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms substituted with fluorine;

[0059] Each independently expresses

[0060] b and c each independently represent 1, 2 or 3; when b and c represent 2 or 3, Each independently the same or different.

[0061] In the cholesteric liquid crystal composition of the present invention, preferably, the compound represented by the aforementioned formula IV is selected from at least one compound represented by the following formulas IV-1 to IV-82,

[0062]

[0063]

[0064]

[0065]

[0066]

[0067] in,

[0068] R3 independently represents H, F, an alkyl group having 1 to 15 carbon atoms, an alkyl group having 1 to 15 carbon atoms substituted with fluorine, an alkoxy group having 1 to 15 carbon atoms, an alkoxy group having 1 to 15 carbon atoms substituted with fluorine, an alkenyl group having 2 to 15 carbon atoms, an alkenyl group having 2 to 15 carbon atoms substituted with fluorine, an ester group having 2 to 15 carbon atoms, an ester group having 2 to 15 carbon atoms, an ester group having 2 to 15 carbon atoms substituted with fluorine, an alkenyloxy group having 3 to 15 carbon atoms, or an alkenyloxy group having 3 to 15 carbon atoms substituted with fluorine, and any one or more -CH2- groups represented by R3 are optionally replaced by cyclopentylene, cyclobutylene or cyclopropylene;

[0069] R 31 It represents an alkyl group having 1 to 15 carbon atoms, an alkyl group having 1 to 15 carbon atoms substituted with fluorine, an alkoxy group having 1 to 15 carbon atoms, an alkenyl group having 2 to 15 carbon atoms, or an alkenyl group having 2 to 15 carbon atoms substituted with fluorine.

[0070] In the cholesteric liquid crystal composition of the present invention, preferably, the additive further comprises one or more chiral active substances represented by the following formulas V, VI and VII:

[0071]

[0072] R8, R9, R 10 , R 11 each independently represents H, F, an alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms substituted with fluorine, an alkoxy group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms substituted with fluorine, an alkenyl group having 2 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms substituted with fluorine, an alkenyloxy group having 3 to 8 carbon atoms, or an alkenyloxy group having 3 to 8 carbon atoms substituted with fluorine; and R8, R9, R 10 , R 11 Any one or more -CH2- in the groups shown are optionally replaced by cyclopentylene, cyclobutylene or cyclopropylene;

[0073] X 15 , X 16 Each independently represents H or F; at least one of them is F;

[0074] q represents 1 or 2;

[0075] express

[0076] In the cholesteric liquid crystal composition of the present invention, preferably, the compound represented by the aforementioned formula V is selected from at least one compound represented by the following formulas V-1 to V-6,

[0077]

[0078] In the cholesteric liquid crystal composition of the present invention, preferably, the compound represented by the aforementioned formula VI is a compound represented by formula VI-1,

[0079]

[0080] In the cholesteric liquid crystal composition of the present invention, preferably, the compound represented by the aforementioned formula VII is selected from at least one compound represented by the following formulas VII-1 to VII-6,

[0081]

[0082]

[0083] R 11 represents H, F, an alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms substituted with fluorine, an alkoxy group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms substituted with fluorine, an alkenyl group having 2 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms substituted with fluorine, an alkenyloxy group having 3 to 8 carbon atoms, or an alkenyloxy group having 3 to 8 carbon atoms substituted with fluorine; and R 11 Any one or more -CH2- groups in the groups shown are optionally replaced by cyclopentylene, cyclobutylene or cyclopropylene.

[0084] In the cholesteric liquid crystal composition of the present invention, it is further preferred that the mass of the chiral active substance is 0.5%-16% of the mass of the liquid crystal component, and more preferably 2.0%-12%.

[0085] Optionally, the present invention adds the compound represented by formula I, formula II and / or formula III to a liquid crystal mixture composed of a liquid crystal component composed of a compound represented by formula IV and a chiral active substance represented by formula V, VI and VII, and after mixing, heats to 60-120° C. for 0.5-6 hours.

[0086] In the cholesteric liquid crystal composition of the present invention, preferably, the additive further comprises one or more initiators.

[0087] Optionally, the initiator of the present invention includes an azo initiator, such as: at least one of diisobutyronitrile, azobisisovaleronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate, azobisisobutyronitrile formamide and azobiscyclohexylcarbonitrile; and also includes at least one of benzoyl peroxide, tert-butyl benzoyl peroxide, methyl ethyl ketone peroxide, tert-butyl peroxypivalate, di(3,3,5-trimethylhexanoyl) peroxide, tert-butyl peroxyneodecanoate, bis(2-ethylhexyl) peroxydicarbonate and isopropylphenyl peroxyneodecanoate.

[0088] The mass of the initiator mentioned above in the present invention is 0.02%-1% of the mass of the liquid crystal component, and more preferably 0.02%-0.5%.

[0089] Various functional dopants, such as antioxidants and light stabilizers, may be added to the cholesteric liquid crystal composition of the present invention. The mass of the dopant is preferably 0.01% to 1% of the mass of the liquid crystal component.

[0090] Preferably, the antioxidant is selected from at least one of the following compounds,

[0091]

[0092] Wherein, t represents an integer from 1 to 10,

[0093] Preferably, the light stabilizer is selected from the group consisting of the compounds represented by the following formula T-5 or T-6, or both.

[0094]

[0095] in,

[0096] S represents an integer of 1-10.

[0097] The present invention also relates to a cholesteric liquid crystal display element or a liquid crystal display comprising any one of the above cholesteric liquid crystal compositions; the display element or the display is an active matrix addressed display element or the display or a passive matrix addressed display element or the display.

[0098] The cholesteric liquid crystal display element or liquid crystal display comprising the cholesteric liquid crystal composition of the present invention has excellent pressure resistance and good reliability, and can effectively improve the pressure resistance problem of the cholesteric liquid crystal display element or liquid crystal display.

[0099] Example

[0100] In order to explain the present invention more clearly, the present invention is further described below in conjunction with preferred embodiments. It should be understood by those skilled in the art that the following specific description is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention.

[0101] In the present invention, the preparation methods are conventional methods unless otherwise specified, the raw materials used are all available from public commercial channels unless otherwise specified, the percentages are all mass percentages, the temperatures are in degrees Celsius (°C), and the specific meanings of other symbols and test conditions are as follows:

[0102] Cp represents the clearing point of liquid crystal (℃), measured by DSC quantitative method;

[0103] Δn represents optical anisotropy, Δn = n e -n o, where n o is the refractive index of ordinary light, n e It is the refractive index of extraordinary light, tested at 25±2℃, 589nm, and Abbe refractometer.

[0104] Δε represents dielectric anisotropy, Δε=ε ∥ -ε ⊥ , where ε ∥ is the dielectric constant parallel to the molecular axis, ε ⊥ is the dielectric constant perpendicular to the molecular axis, the test conditions are 25±0.5℃, 20 μm antiparallel box, INSTEC:ALCT-IR1 test;

[0105] η represents the rotational viscosity of the fluid (mPa·s), the test condition is 25±0.5℃, and the test equipment is: Brookfield DV2T viscometer;

[0106] K 11 is the splay elastic constant, K 33 is the bending elastic constant, the test conditions are: 25 °C, INSTEC:ALCT-IR1, 20 μm antiparallel box;

[0107] Power consumption current, the test conditions are 25±2℃, voltage is 4V, 64HZ pulse square wave, the test box uses 5 micron ITO liquid crystal box, and the test equipment is Model 3200 electric test machine;

[0108] The reflection wavelength refers to the light of a specific wavelength range reflected by the cholesteric liquid crystal. The test conditions are a 5-micron ITO liquid crystal cell and the test instrument is the liquid crystal comprehensive tester DMS-501.

[0109] The preparation method of the cholesteric liquid crystal composition containing additives in each embodiment is as follows: the components of the cholesteric liquid crystal composition are weighed according to the ratio and put into a stainless steel beaker, the stainless steel beaker containing the components of the liquid crystal mixture is placed on a magnetic stirring instrument, a magnetic rotor is added to the stainless steel beaker, and the mixture is stirred evenly at room temperature to obtain a liquid crystal composition.

[0110] The method for preparing a cholesteric liquid crystal sample is as follows: the uniformly stirred cholesteric liquid crystal composition is poured through a pouring machine under a specific pouring procedure at room temperature, and after the liquid crystal sample is poured, it is sealed with a sealing glue.

[0111] Compression resistance test method: Place the LCD sample on the test platform, apply a force of 10N with a 1mm diameter tester, and measure the thickness of the residual strokes left by the tester across the cholesteric liquid crystal sample panel. The smaller the stroke width, the better the compression resistance.

[0112] The monomer structures of the components of the cholesteric liquid crystal composition in the embodiment of the present invention are represented by codes, and the code representation methods of the liquid crystal ring structure, terminal group and connecting group are shown in Tables 1 and 2 below.

[0113] Table 1 Corresponding codes of ring structure

[0114]

[0115]

[0116] Table 2 Corresponding codes of terminal groups and linking groups

[0117]

[0118] Example:

[0119] Its code is CPWP-3-O1;

[0120] Its code is CC-Cp-V1;

[0121] Its code is CPZU-3-CN;

[0122] Its code is DG-3-F;

[0123] Its code is PyGP-2-CN;

[0124] Its code is PGQU-2-F;

[0125] Its code is PGP-Cpr1-2;

[0126] Its code is PP-1-2V;

[0127] Its code is PGP-5-2.

[0128] The present invention is described below using the following specific embodiments:

[0129] Example 1

[0130] The formula of the cholesteric liquid crystal composition and the corresponding properties are shown in Table 3 below.

[0131] Table 3 Formulation of the liquid crystal composition of Example 1 and corresponding properties

[0132]

[0133]

[0134] Preparation and compression test of anti-compression cholesteric liquid crystal samples:

[0135] 1. After stirring the mixture in the above table evenly, use a crystal filling machine to pour the above components of the cholesteric liquid crystal mixture into the liquid crystal screen at room temperature, and seal the crystal filling port of the liquid crystal screen with sealing glue.

[0136] 2. Place the liquid crystal sample poured in step 1 into a 100°C oven for thermal polymerization and keep it at 100°C for 6 hours to obtain a liquid crystal sample with good compression resistance.

[0137] 3. LCD sample compression test method: Place the LCD sample on the test platform, apply a force of 10N with a 1mm diameter tester, and measure the thickness of the residual strokes left by the tester across the panel.

[0138] Example 2

[0139] The formula of the cholesteric liquid crystal composition and the corresponding properties are shown in Table 4 below.

[0140] Table 4 Formulation of the liquid crystal composition of Example 2 and corresponding properties

[0141]

[0142] Preparation and compression test of anti-compression cholesteric liquid crystal samples:

[0143] 1. After stirring the mixture in the above table evenly, use a crystal filling machine to pour the above components of the cholesteric liquid crystal mixture into the liquid crystal screen at room temperature, and seal the crystal filling port of the liquid crystal screen with sealing glue.

[0144] 2. Place the liquid crystal sample poured in step 1 into an oven at 80°C for thermal polymerization and keep it at 90°C for 2 hours to obtain a liquid crystal sample with good compression resistance.

[0145] 3. LCD sample compression test method: Place the LCD sample on the test platform, apply a force of 10N with a 1mm diameter tester, and measure the thickness of the residual strokes left by the tester across the panel.

[0146] Example 3

[0147] The formula of the cholesteric liquid crystal composition and the corresponding properties are shown in Table 5 below.

[0148] Table 5 Formulation of the liquid crystal composition of Example 3 and corresponding properties

[0149]

[0150]

[0151] Preparation and compression test of anti-compression cholesteric liquid crystal samples:

[0152] 1. After stirring the mixture in the above table evenly, use a crystal filling machine to pour the above components of the cholesteric liquid crystal mixture into the liquid crystal screen at room temperature, and seal the crystal filling port of the liquid crystal screen with sealing glue.

[0153] 2. Place the liquid crystal sample poured in step 1 into a 90°C oven for thermal polymerization and keep it at 90°C for 6 hours to obtain a liquid crystal sample with good compression resistance.

[0154] 3. LCD sample compression test method: Place the LCD sample on the test platform, apply a force of 10N with a 1mm diameter tester, and measure the thickness of the residual strokes left by the tester across the panel.

[0155] Example 4

[0156] The formula of the cholesteric liquid crystal composition and the corresponding properties are shown in Table 6 below.

[0157] Table 6 Formulation of the liquid crystal composition of Example 4 and corresponding properties

[0158]

[0159]

[0160] Preparation and compression test of anti-compression cholesteric liquid crystal samples:

[0161] 1. After stirring the mixture in the above table evenly, use a crystal filling machine to pour the above components of the cholesteric liquid crystal mixture into the liquid crystal screen at room temperature, and seal the crystal filling port of the liquid crystal screen with sealing glue.

[0162] 2. Place the liquid crystal sample poured in step 1 into an oven at 80°C for thermal polymerization and keep it at 100°C for 6 hours to obtain a liquid crystal sample with good compression resistance.

[0163] 3. LCD sample compression test method: Place the LCD sample on the test platform, apply a force of 10N with a 1mm diameter tester, and measure the thickness of the residual strokes left by the tester across the panel.

[0164] Example 5

[0165] The formula of the cholesteric liquid crystal composition and the corresponding properties are shown in Table 7 below.

[0166] Table 7 Formulation of the liquid crystal composition of Example 5 and corresponding properties

[0167]

[0168]

[0169] Preparation and compression test of anti-compression cholesteric liquid crystal samples:

[0170] 1. After stirring the mixture in the above table evenly, use a crystal filling machine to pour the above components of the cholesteric liquid crystal mixture into the liquid crystal screen at room temperature, and seal the crystal filling port of the liquid crystal screen with sealing glue.

[0171] 2. Place the liquid crystal sample poured in step 1 into an oven at 80°C for thermal polymerization and keep it at 80°C for 2 hours to obtain a liquid crystal sample with good compression resistance.

[0172] 3. LCD sample compression test method: Place the LCD sample on the test platform, apply a force of 10N with a 1mm diameter tester, and measure the thickness of the residual strokes left by the tester across the panel.

[0173] Example 6

[0174] The formula of the cholesteric liquid crystal composition and the corresponding properties are shown in Table 8 below.

[0175] Table 8 Formulation and corresponding properties of the liquid crystal composition of Example 6

[0176]

[0177]

[0178] Preparation and compression test of anti-compression cholesteric liquid crystal samples:

[0179] 1. After stirring the mixture in the above table evenly, use a crystal filling machine to pour the above components of the cholesteric liquid crystal mixture into the liquid crystal screen at room temperature, and seal the crystal filling port of the liquid crystal screen with sealing glue.

[0180] 2. Place the liquid crystal sample poured in step 1 into an oven at 80°C for thermal polymerization and keep it at 80°C for 2 hours to obtain a liquid crystal sample with good compression resistance.

[0181] 3. LCD sample compression test method: Place the LCD sample on the test platform, apply a force of 10N with a 1mm diameter tester, and measure the thickness of the residual strokes left by the tester across the panel.

[0182] Example 7

[0183] The formula of the cholesteric liquid crystal composition and the corresponding properties are shown in Table 9 below.

[0184] Table 9 Formulation of the liquid crystal composition of Example 7 and corresponding properties

[0185]

[0186]

[0187] Preparation and compression test of anti-compression cholesteric liquid crystal samples:

[0188] 1. After stirring the mixture in the above table evenly, use a crystal filling machine to pour the above components of the cholesteric liquid crystal mixture into the liquid crystal screen at room temperature, and seal the crystal filling port of the liquid crystal screen with sealing glue.

[0189] 2. Place the liquid crystal sample poured in step 1 into an oven at 80°C for thermal polymerization and keep it at 80°C for 2 hours to obtain a liquid crystal sample with good compression resistance.

[0190] 3. LCD sample compression test method: Place the LCD sample on the test platform, apply a force of 10N with a 1mm diameter tester, and measure the thickness of the residual strokes left by the tester across the panel.

[0191] Comparative Example 1

[0192] The formula of the cholesteric liquid crystal composition and the corresponding properties are shown in Table 10 below.

[0193] Table 10 Formulation of liquid crystal composition of comparative example 1 and corresponding properties

[0194]

[0195]

[0196] The preparation and compression test of the compression-resistant cholesteric liquid crystal sample are the same as those in Example 1.

[0197] Comparative Example 2

[0198] The formula of the cholesteric liquid crystal composition and the corresponding properties are shown in Table 11 below.

[0199] Table 11 Formula and corresponding properties of liquid crystal composition of comparative example 2

[0200]

[0201]

[0202] The preparation and compression test of the compression-resistant cholesteric liquid crystal sample are the same as those in Example 2.

[0203] Comparative Example 3

[0204] The formula and corresponding properties of the cholesteric liquid crystal composition are shown in Table 12 below

[0205] Table 12 Formulation and corresponding properties of the liquid crystal composition of Comparative Example 3

[0206]

[0207]

[0208] The preparation and compression test of the compression-resistant cholesteric liquid crystal sample are the same as those in Example 3.

[0209] The reflection wavelength of cholesteric liquid crystal refers to the different colors of cholesteric liquid crystal. A reflection wavelength of 450nm refers to the reflection color of the liquid crystal as blue, a reflection wavelength of 520nm refers to the reflection color as green, and a reflection wavelength of 620nm refers to the reflection color as red. The different colors of cholesteric liquid crystal are selected arbitrarily and do not need to be specified. The anti-pressing effect has nothing to do with the reflection wavelength of the liquid crystal, but is only related to the liquid crystal additives shown in Formula I, Formula II and Formula III.

[0210] Before and after the polymerizable compounds represented by Formula I, Formula II and Formula III are added to the cholesteric liquid crystal, the reflection wavelength does not change much and the parameters remain relatively stable; the power consumption current of the liquid crystal sample does not change much and the parameters remain relatively stable.

[0211] Compared with the examples, the liquid crystal composition of Comparative Example 1, Comparative Example 2 and Comparative Example 3 does not use the polymerizable compound and initiator of Formula I of the present invention compared with Example 1; the liquid crystal composition of Comparative Example 1 does not use the polymerizable compound and initiator of Formula I and Formula III of the present invention compared with Example 4. Similarly, compared with the liquid crystal composition of Example 2, the liquid crystal composition of Comparative Example 2 does not use the polymerizable compound and initiator of Formula II of the present invention compared with Example 2; compared with the liquid crystal composition of Example 5, the liquid crystal composition of Comparative Example 2 does not use the polymerizable compound and initiator of Formula I and Formula II of the present invention compared with Example 5. Similarly, the liquid crystal composition of comparative example 3 is compared with the liquid crystal composition of embodiment 3, and the liquid crystal composition of comparative example 3 does not use the polymerizable compound and initiator shown in formula III of the present invention; the liquid crystal composition of comparative example 3 is compared with the liquid crystal composition of embodiment 6, and the liquid crystal composition of comparative example 3 does not use the polymerizable compound and initiator shown in formula II and formula III of the present invention; the liquid crystal composition of comparative example 3 is compared with the liquid crystal composition of embodiment 7, and the liquid crystal composition of comparative example 3 does not use the polymerizable compound and initiator shown in formula I, formula II, and formula III of the present invention. Under the same conditions, the pressing test is carried out, and the pressing resistance of comparative examples 1, 2 and 3 is poor, and thicker stripes appear under the same pressure and do not disappear, indicating that the liquid crystal panel has poor pressure resistance to external pressure.

[0212] Therefore, the cholesteric liquid crystal composition including the additive of the present invention has an excellent anti-pressing effect after polymerization.

[0213] The liquid crystal display element after thermal polymerization of the cholesteric liquid crystal containing the additive of the present invention has good anti-pressing performance, can be used in the field of optical devices such as liquid crystal electronic books, and can effectively improve the problem of anti-pressing difference of the cholesteric liquid crystal display element.

[0214] Obviously, the above embodiments disclosed in the present invention are only examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made on the basis of the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A cholesteric liquid crystal composition, characterized in that: The invention comprises a liquid crystal component and an additive, wherein the additive comprises at least one polymerizable compound, and the polymerizable compound is selected from one or more compounds represented by formula I, compounds represented by formula II and compounds represented by formula III. in, R1 and R2 each independently represent H, F, an alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms substituted with fluorine, an alkoxy group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms substituted with fluorine, an alkenyl group having 2 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms substituted with fluorine, an ester group having 2 to 6 carbon atoms, an ester group having 2 to 6 carbon atoms, an ester group having 2 to 6 carbon atoms, an alkenyloxy group having 3 to 8 carbon atoms, or an alkenyloxy group having 3 to 8 carbon atoms substituted with fluorine, and any one or more -CH2- groups represented by R1 are optionally replaced by cyclopentylene, cyclobutylene or cyclopropylene; X and Z each independently represent -O-, -COO-, -CH2-, -CH2O- or -C2H4-; X1, X4, X7, X 10 Each independently represents H, F or methyl; X2, X3, X5, X6, X8, X9, X 11 , X 12 Each independently represents H or F; m, n, and a each independently represent 0, 1, or 2; Each independently expresses Each independently expresses 2. The cholesteric liquid crystal composition according to claim 1, characterized in that: The compound represented by formula I is selected from at least one compound represented by the following formulas I-1 to I-16, and / or The compound represented by formula II is selected from at least one compound represented by the following formulas II-1 to II-16, in, R1 independently represents H, F, an alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms substituted with fluorine, an alkoxy group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms substituted with fluorine, an alkenyl group having 2 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms substituted with fluorine, an ester group having 2 to 6 carbon atoms, an ester group having 2 to 6 carbon atoms, an ester group having 2 to 6 carbon atoms, an alkenyloxy group having 3 to 8 carbon atoms, or an alkenyloxy group having 3 to 8 carbon atoms substituted with fluorine, and any one or more -CH2- in the group represented by R1 is optionally replaced by a cyclopentylene, a cyclobutylene, or a cyclopropylene group; and / or The compound represented by formula III is selected from at least one compound represented by the following formulas III-1 to III-9, 3. The cholesteric liquid crystal composition according to claim 2, characterized in that: The compound represented by formula I is selected from at least one compound represented by formula I-1 to I-8; and / or The mass of the compound represented by formula I is 0-16% of the mass of the liquid crystal component; and / or The compound represented by formula II is selected from at least one compound represented by formula II-1, II-2, II-9, II-10 and II-11; and / or The mass of the compound represented by formula II is 0-12% of the mass of the liquid crystal component; and / or The compound represented by formula III is selected from at least one compound represented by formula III-3, III-4, and III-5; and / or The mass of the compound represented by formula III is 0-12% of the mass of the liquid crystal component.

4. The cholesteric liquid crystal composition according to any one of claims 1 to 3, characterized in that: The liquid crystal component comprises one or more compounds represented by formula IV, in, R3 independently represents H, F, an alkyl group having 1 to 15 carbon atoms, an alkyl group having 1 to 15 carbon atoms substituted with fluorine, an alkoxy group having 1 to 15 carbon atoms, an alkoxy group having 1 to 15 carbon atoms substituted with fluorine, an alkenyl group having 2 to 15 carbon atoms, an alkenyl group having 2 to 15 carbon atoms substituted with fluorine, an ester group having 2 to 15 carbon atoms, an ester group having 2 to 15 carbon atoms, an ester group having 2 to 15 carbon atoms substituted with fluorine, an alkenyloxy group having 3 to 15 carbon atoms, or an alkenyloxy group having 3 to 15 carbon atoms substituted with fluorine, and any one or more -CH2- groups represented by R3 are optionally replaced by cyclopentylene, cyclobutylene or cyclopropylene; Z1 represents a single bond, -C≡C-, COO or -CF2O-; X 13 represents F, CN, an alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms substituted with fluorine, an alkoxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms substituted with fluorine; Each independently expresses b and c each independently represent 1, 2 or 3; when b and c represent 2 or 3, Each independently the same or different.

5. The cholesteric liquid crystal composition according to claim 4, characterized in that: The compound represented by formula IV is selected from at least one compound represented by the following formulas IV-1 to IV-82, in, R3 independently represents H, F, an alkyl group having 1 to 15 carbon atoms, an alkyl group having 1 to 15 carbon atoms substituted with fluorine, an alkoxy group having 1 to 15 carbon atoms, an alkoxy group having 1 to 15 carbon atoms substituted with fluorine, an alkenyl group having 2 to 15 carbon atoms, an alkenyl group having 2 to 15 carbon atoms substituted with fluorine, an ester group having 2 to 15 carbon atoms, an ester group having 2 to 15 carbon atoms, an ester group having 2 to 15 carbon atoms substituted with fluorine, an alkenyloxy group having 3 to 15 carbon atoms, or an alkenyloxy group having 3 to 15 carbon atoms substituted with fluorine, and any one or more -CH2- groups represented by R3 are optionally replaced by cyclopentylene, cyclobutylene or cyclopropylene; R 31 It represents an alkyl group having 1 to 15 carbon atoms, an alkyl group having 1 to 15 carbon atoms substituted with fluorine, an alkoxy group having 1 to 15 carbon atoms, an alkenyl group having 2 to 15 carbon atoms, or an alkenyl group having 2 to 15 carbon atoms substituted with fluorine.

6. The cholesteric liquid crystal composition according to claim 5, characterized in that: The additive further comprises one or more chiral active substances represented by the following formulas V, VI and VII, R8, R9, R 10 , R 11 each independently represents H, F, an alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms substituted with fluorine, an alkoxy group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms substituted with fluorine, an alkenyl group having 2 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms substituted with fluorine, an alkenyloxy group having 3 to 8 carbon atoms, or an alkenyloxy group having 3 to 8 carbon atoms substituted with fluorine; and R8, R9, R 10 , R 11 Any one or more -CH2- in the groups shown are optionally replaced by cyclopentylene, cyclobutylene or cyclopropylene; X 15 , X 16 Each independently represents H or F; at least one of them is F; q represents 1 or 2; express 7. The cholesteric liquid crystal composition according to claim 6, characterized in that: The compound represented by formula V is selected from at least one compound represented by the following formulas V-1 to V-6, and / or The compound represented by formula VI is the compound represented by formula VI-1, and / or The compound represented by formula VII is selected from at least one compound represented by the following formulas VII-1 to VII-6, R 11 represents H, F, an alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms substituted with fluorine, an alkoxy group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms substituted with fluorine, an alkenyl group having 2 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms substituted with fluorine, an alkenyloxy group having 3 to 8 carbon atoms, or an alkenyloxy group having 3 to 8 carbon atoms substituted with fluorine; and R 11 Any one or more -CH2- in the groups shown are optionally replaced by cyclopentylene, cyclobutylene or cyclopropylene; and / or The mass of the chiral active substance is 0.5%-16% of the mass of the liquid crystal component.

8. The cholesteric liquid crystal composition according to any one of claims 1 to 7, characterized in that: The additives also include one or more thermal initiators.

9. A liquid crystal display element, characterized in that: The cholesteric liquid crystal composition comprises the cholesteric liquid crystal composition according to any one of claims 1 to 8, wherein the liquid crystal display element is an active matrix addressing display element or a passive matrix addressing display element.

10. A liquid crystal display, characterized in that: The cholesteric liquid crystal composition comprises the cholesteric liquid crystal composition according to any one of claims 1 to 8, wherein the liquid crystal display is an active matrix addressing display or a passive matrix addressing display.

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