Negative liquid crystal composition and use thereof

Abstract

This invention relates to a negative liquid crystal composition and its application, belonging to the field of liquid crystal materials. The negative liquid crystal composition comprises at least one dielectric negative compound represented by general formula I: wherein, R 11 R represents an alkyl group with 1-12 carbon atoms or an alkenyl group with 2-12 carbon atoms; 12 The radicals represent alkyl, alkoxy, or alkenyl groups with 1-12 carbon atoms; a represents 0 or 1, and f represents 0 or 1. In the liquid crystal composition of the present invention, the vertical dielectric constant ε⊥ and the ε⊥ / |Δε| ratio are high, resulting in good transmittance, high contrast, a large K33 value, low rotational viscosity, and fast response time. Simultaneously, the liquid crystal composition of the present invention exhibits good low-temperature storage stability and low rotational viscosity, which can reduce the response time of liquid crystal displays.

Description

Technical Field

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

[0002] Liquid crystal display elements, made using the refractive index anisotropy and dielectric anisotropy of liquid crystal compounds, are widely used in display devices such as televisions and monitors. Negative liquid crystal displays are particularly popular due to their high contrast and good viewing angle characteristics. VA panels are ideal for black content and scenes, offering very high contrast and deep blacks. In recent years, with the increasing number of display applications, the demand for display time in devices such as gaming continues to rise. Compared to lower refresh rates, higher refresh rates offer advantages in motion clarity. The contrast of negative liquid crystals is related to the ratio of ε⊥ / |Δε∣. However, due to the characteristics of liquid crystal materials, ε⊥ is relatively small, resulting in lower transmittance and lower contrast. Therefore, there is a need for a liquid crystal material with high dielectric constant, fast response, and stable low-temperature performance. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention discloses a liquid crystal composition comprising compound I, compound II, compound III, and dicyclohexane compound IV. This type of liquid crystal composition, when used as a liquid crystal material, exhibits low rotational viscosity, which can shorten the response time. Simultaneously, the components have good mutual solubility, improving low-temperature performance. The liquid crystal composition of this invention contains a biphenyl-based negative compound with meta-terminal substituents, resulting in an overall negative dielectric.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A negative liquid crystal composition comprising at least one dielectric negative compound represented by general formula I:

[0006]

[0007] Among them, R 11 Indicates an alkyl group with 1-12 carbon atoms or an alkenyl group with 2-12 carbon atoms;

[0008] R 12 It represents an alkyl group with 1-12 carbon atoms, an alkoxy group with 1-12 carbon atoms, or an alkenyl group with 2-12 carbon atoms;

[0009] a represents 0 or 1, f represents 0 or 1.

[0010] The liquid crystal composition contains a negative compound with a cyclohexene group between two negative groups. The presence of negative groups at both ends allows the compound to maintain a large negative dielectric. The connection between the cyclohexyl or cyclohexene group in the middle and the negative group enables the negative compound to have good compatibility with other components in the mixed liquid crystal. At the same time, the compound also has a large K33, which can effectively reduce the response time of the liquid crystal display.

[0011] A negative liquid crystal composition having a negative dielectric constant, comprising at least one dielectric-negative compound of general formula I as a first component:

[0012]

[0013] Among them, R 11 Indicates an alkyl group with 1-12 carbon atoms or an alkenyl group with 2-12 carbon atoms;

[0014] R 12 It represents an alkyl group with 1-12 carbon atoms, an alkoxy group with 1-12 carbon atoms, or an alkenyl group with 2-12 carbon atoms;

[0015] a represents 0 or 1, f represents 0 or 1;

[0016] At least one compound represented by general formula II shall be used as the second component:

[0017]

[0018] Among them, R 21 R 22 Each of the above can be independently represented as an alkyl group with 1-12 carbon atoms, an alkoxy group with 1-12 carbon atoms, or an alkenyl group with 2-12 carbon atoms;

[0019] Z2 represents a CC single bond - or -CH2O-;

[0020] b represents 0 or 1;

[0021] At least one compound represented by general formula III serves as the third component:

[0022]

[0023] Among them, R 31 R 32 Each of the above can be independently represented as an alkyl group with 1-12 carbon atoms, an alkoxy group with 1-12 carbon atoms, or an alkenyl group with 2-12 carbon atoms;

[0024] Rings C1, C2, and C3 are each represented independently. and At most one H on the ring can be replaced by F; and at least one of rings C1, C2, and C3 is

[0025] c represents 0 or 1; d represents 0 or 1;

[0026] And at least one compound represented by general formula IV as the fourth component:

[0027]

[0028] Among them, R 41 R 42 Each of the above can be independently represented as an alkyl group with 1-12 carbon atoms, an alkoxy group with 1-12 carbon atoms, or an alkenyl group with 2-12 carbon atoms;

[0029] The content of the compound represented by formula I is 1-30% by mass percentage, the content of the compound represented by formula II is 1-40%, the content of the compound represented by formula III is 1-50%, and the content of the compound represented by formula IV is 5-55%.

[0030] The liquid crystal composition further comprises one or more compounds of general formulas MA to MG:

[0031]

[0032]

[0033] Among them, R M1 R M2 Each of the above can be independently represented as an alkyl group with 1-12 carbon atoms, an alkenyl group with 2-12 carbon atoms, or an alkoxy group with 1-12 carbon atoms; in liquid crystal compounds, the mass content of the compound represented by general formula M is 1-60%.

[0034] Furthermore, the compound represented by general formula I is selected from one or more compounds in the group consisting of compounds IA to IC:

[0035]

[0036] Among them, R 11 R represents an alkyl group with 1-12 carbon atoms or an alkenyl group with 2-12 carbon atoms; 12 It represents an alkyl group with 1-12 carbon atoms, an alkoxy group with 1-12 carbon atoms, or an alkenyl group with 2-12 carbon atoms.

[0037] Furthermore, the compound represented by general formula I is selected from one or more of the following compounds:

[0038]

[0039]

[0040]

[0041]

[0042] The lower limit of the weight percentage of the compound of general formula I relative to the total weight of the liquid crystal composition of the present invention is 1%, 1.5%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 14%, 16%, 20%, 22%, 24%, or 26%; the upper limit of the weight percentage of the compound of general formula I relative to the total weight of the liquid crystal composition of the present invention is 30%, 28%, 26%, 24%, 20%, 18%, 16%, 15%, 14%, 12%, or 10%.

[0043] Furthermore, the compound represented by general formula II is selected from one or more of the following compounds II-1 to II-58:

[0044]

[0045]

[0046]

[0047] The lower limit of the weight percentage of the compound of formula II relative to the total weight of the liquid crystal composition of the present invention is 1%, 1.5%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 14%, 16%, 20%, 22%, 24%, or 26%; the upper limit of the weight percentage of the compound of formula II relative to the total weight of the liquid crystal composition of the present invention is 40%, 38%, 35%, 30%, 28%, 26%, 24%, 20%, 18%, 16%, 15%, 14%, 12%, or 10%.

[0048] Furthermore, the compound represented by general formula III is selected from one or more of the following compounds:

[0049]

[0050] Among them, R C1 R C2 Each of the above can be independently represented as an alkyl group with 1-12 carbon atoms, an alkoxy group with 1-12 carbon atoms, or an alkenyl group with 2-12 carbon atoms.

[0051] In some embodiments of the present invention, preferably, the compound represented by general formula III is selected from one or more compounds in the group consisting of compounds III-1 to III-68:

[0052]

[0053]

[0054]

[0055] The lower limit of the weight percentage of the compound of formula III relative to the total weight of the liquid crystal composition of the present invention is 1%, 1.5%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 14%, 16%, 20%, 22%, 24%, or 26%; the upper limit of the weight percentage of the compound of formula III relative to the total weight of the liquid crystal composition of the present invention is 50%, 48%, 45%, 40%, 38%, 35%, 30%, 28%, 26%, 24%, 20%, 18%, 16%, 15%, 14%, 12%, or 10%.

[0056] In some embodiments of the present invention, preferably, the compound represented by general formula IV is selected from one or more compounds in the group consisting of compounds IV-1 to IV-18:

[0057]

[0058]

[0059] The lower limit of the weight percentage of the compound of formula IV relative to the total weight of the liquid crystal composition of the present invention is 5%, 6%, 7%, 8%, 9%, 10%, 12%, 14%, 16%, 20%, 22%, 24%, or 26%; the upper limit of the weight percentage of the compound of formula IV relative to the total weight of the liquid crystal composition of the present invention is 54%, 52%, 50%, 48%, 45%, 40%, 38%, 35%, 30%, 28%, 26%, 24%, 20%, 18%, 16%, 15%, 14%, 12%, or 10%.

[0060] In some embodiments of the present invention, the compound represented by general formula M is selected from one or more of the following compounds M-1 to M-36:

[0061]

[0062]

[0063]

[0064] The lower limit of the weight percentage of the compound of general formula M relative to the total weight of the liquid crystal composition of the present invention is 1%, 1.5%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 14%, 16%, 20%, 22%, 24%, or 26%; the upper limit of the weight percentage of the compound of general formula M relative to the total weight of the liquid crystal composition of the present invention is 60%, 58%, 56%, 54%, 52%, 50%, 48%, 45%, 40%, 38%, 35%, 30%, 28%, 26%, 24%, 20%, 18%, 16%, 15%, 14%, 12%, or 10%.

[0065] One or more chiral agents may be added to the liquid crystal mixture, and the content of the chiral agent accounts for 0.01-5% of the total mass of the liquid crystal composition.

[0066] Furthermore, the chiral compound is selected from one or more of the following compounds:

[0067]

[0068]

[0069] as well as

[0070]

[0071] On the other hand, the liquid crystal composition provided by the present invention also contains one or more additives known to those skilled in the art and described in the literature, such as stabilizers. A stabilizer may also be added to the liquid crystal mixture, wherein the stabilizer has a mass content of 0.01-5%.

[0072] For example, one or more stabilizers with the following structures can be added to the liquid crystal mixture of the present invention:

[0073]

[0074]

[0075]

[0076]

[0077] Preferably, the stabilizer is selected from one or more stabilizers with the following structures:

[0078]

[0079] In stabilizers, n represents a positive integer from 1 to 12 (e.g., 1, 2, 3, 4, 5, 6, 8, 10, or 11).

[0080] In embodiments of the present invention, the stabilizer preferably accounts for 0-5% of the total weight of the liquid crystal composition; more preferably, the stabilizer accounts for 0-1% of the total weight of the liquid crystal composition; and as a particularly preferred embodiment, the stabilizer accounts for 0.01-0.2% of the total weight of the liquid crystal composition.

[0081] At least one polymerizable compound may also be added to the liquid crystal mixture.

[0082] Furthermore, the polymerizable compound is selected from one or more of the following compounds PA to PK:

[0083]

[0084]

[0085] In this context, Sp2 represents a spacer group or a single bond. The spacer group is defined as a straight-chain or branched alkyl group with 1-6 carbon atoms. P1 and P2 each independently represent a methacrylate group or an acrylate group.

[0086] More preferably, the compound represented by general formula P is selected from one or more compounds represented by structural formulas P-1 to P-50:

[0087]

[0088]

[0089]

[0090]

[0091] In some embodiments of the present invention, the compound of general formula P accounts for 0.001% to 5% by weight of the liquid crystal composition, for example, 0.005%, 0.01%, 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, etc.; preferably, the compound of general formula P accounts for 0.01% to 2% by weight of the liquid crystal composition; more preferably, the compound of general formula P accounts for 0.25% to 0.35% by weight of the liquid crystal composition.

[0092] The application of the liquid crystal composition in the manufacture of liquid crystal display devices, including VA, MVA, PVA, PSVA, IPS and FFS mode liquid crystal display devices.

[0093] Advantages of this invention:

[0094] The liquid crystal composition of this invention exhibits high vertical dielectric constant ε⊥ and a high ε⊥ / ∣Δε∣ ratio, resulting in good transmittance, high contrast, a large K33 value, low rotational viscosity, and fast response time. Furthermore, the liquid crystal composition of this invention demonstrates good low-temperature storage stability and low rotational viscosity, which can reduce the response time of liquid crystal displays.

[0095] The liquid crystal composition contains a negative compound that maintains a large negative dielectric. This negative compound has good compatibility with other components in the mixed liquid crystal. At the same time, this compound also has a large K33, which can effectively reduce the response time of the liquid crystal display. Detailed Implementation

[0096] For ease of explanation, in the following embodiments, the group structures of the liquid crystal compositions are represented by the codes listed in Table 1.

[0097] Table 1. Group structure codes of liquid crystal compounds

[0098]

[0099]

[0100] Take the following compound as an example:

[0101]

[0102] Represented by the code in Table 1, it is 3PGP2.

[0103] For example:

[0104]

[0105] It is represented as 3PGUQUF.

[0106] The abbreviated codes for the test items in the following examples are as follows:

[0107] Cp (°C): Clearing point (nematic-isotropic phase transition temperature);

[0108] Δn: Refractive index anisotropy (589 nm, 25 °C);

[0109] Δε: Dielectric anisotropy (1kHz, 25℃);

[0110] t(ms): Response time (25±0.5℃); Liquid crystal is filled between two glass substrates, and measured using an LCT-5016.

[0111] t = t on +t off :ton t represents the time required for relative transmittance to change from 10% to 90%. off This indicates the time required for the relative transmittance to change from 90% to 10%.

[0112] γ1: Represents the rotational viscosity [mPa·s] measured at 25℃, which is obtained by rotation in a magnetic field;

[0113] Δε=ε || -ε ⊥ , where ε || ε is the dielectric constant parallel to the molecular axis. ⊥ The dielectric constant is perpendicular to the molecular axis. Test conditions: 25℃, 1KHz.

[0114] LTS: Low-temperature storage stability. The liquid crystal mixture is stored in a glass bottle under low-temperature conditions.

[0115] K11: Warp elastic constant;

[0116] K33: Bending elastic constant.

[0117] VHR: Voltage Retention Rate. It is measured using a TOYO LCM-2 when liquid crystal is filled between two glass substrates. The higher the voltage retention rate, the fewer mobile ions there are in the liquid crystal display device, and the better the stability of the liquid crystal display device.

[0118] Pitch: The pitch of a liquid crystal is formed by adding a chiral agent to a nematic liquid crystal compound, resulting in a liquid crystal with a certain pitch. It is measured by filling the space between the liquid crystal and a wedge-shaped cell with a reading microscope.

[0119] Haze: Haze is the percentage of transmitted light intensity that deviates from the incident light angle by more than 2.5° out of the total transmitted light intensity. Higher haze means a decrease in film gloss and transparency, especially in image quality. It is measured using a haze meter.

[0120] Example 1: Mixture M1 was prepared according to the compounds and weight percentages listed in Table 2. It was filled between the two substrates of the liquid crystal display for performance testing. The composition and test data of mixture M1 are shown in Table 2 below.

[0121] Table 2 Composition and properties of the liquid crystal composition in Example 1

[0122]

[0123] Comparative Example 1: Mixture D1 was prepared by preparing each compound and weight percentage as listed in the table below. It was filled between the two substrates of the liquid crystal display for performance testing. The composition and test data of mixture D1 are shown in the table below.

[0124] Table 3. Composition and properties of the liquid crystal composition in Comparative Example 1

[0125]

[0126] Example 2: Mixture M2 was prepared by preparing each compound and weight percentage as listed in the table below. It was filled between the two substrates of the liquid crystal display for performance testing. The composition and test data of mixture M2 are shown in the table below.

[0127] Table 4. Composition and properties of the liquid crystal composition in Example 2

[0128]

[0129] Example 3: Mixture M3 was prepared by preparing each compound and weight percentage as listed in the table below. It was filled between the two substrates of the liquid crystal display for performance testing. The composition and test data of mixture M3 are shown in the table below.

[0130] Table 5. Composition and properties of the liquid crystal composition in Example 3

[0131] category Category Total monomer Proportion Cp 85.1 I 10 M-3OPWO2 10 Δn 0.103 II 41.5 3CWO2 11.0 ε / / 3.2 3CCWO2 12.5 ε⊥ 6 2CPWO2 6.0 Δε -2.8 3CPWO2 12.0 ε⊥ / ∣Δε∣ 2.14285714 III 10 1PP2V1 3 LTS (-20℃) No crystallization after 10 days 3CPP2 7.0 toff 4.7ms IV 38.5 3CCV1 12.0 K11 14.2 3CC2 19.0 K33 15.3 4CC3 7.5 γ1 89

[0132] Example 4: Mixture M4 was prepared by preparing each compound and weight percentage as listed in the table below. It was filled between the two substrates of the liquid crystal display for performance testing. The composition and test data of mixture M4 are shown in the table below.

[0133] Table 6. Composition and properties of the liquid crystal composition in Example 4

[0134]

[0135]

[0136] Example 5: Mixture M5 was prepared by preparing each compound and weight percentage as listed in the table below. It was filled between the two substrates of the liquid crystal display for performance testing. The composition and test data of mixture M5 are shown in the table below.

[0137] Table 7 Composition and properties of the liquid crystal composition in Example 5

[0138]

[0139] Example 6: Mixture M6 was prepared by preparing each compound and weight percentage as listed in the table below. It was filled between the two substrates of the liquid crystal display for performance testing. The composition and test data of mixture M6 are shown in the table below.

[0140] Table 8. Composition and properties of the liquid crystal composition in Example 6

[0141]

[0142]

[0143] Example 7: Mixture M7 was prepared by preparing each compound and weight percentage as listed in the table below. It was filled between the two substrates of the liquid crystal display for performance testing. The composition and test data of mixture M7 are shown in the table below.

[0144] Table 9 Composition and properties of the liquid crystal composition in Example 7

[0145]

[0146] An additional 400 ppm of additive was added to the above mixture:

[0147]

[0148] Example 8: Mixture M8 was prepared by preparing each compound and weight percentage as listed in the table below. It was filled between the two substrates of the liquid crystal display for performance testing. The composition and test data of mixture M8 are shown in the table below.

[0149] Table 10 Composition and properties of the liquid crystal composition in Example 8

[0150]

[0151]

[0152] As can be seen from Examples 1-8 and Comparative Example 1 above, the liquid crystal composition of the present invention has high transmittance and contrast. Simultaneously, the liquid crystal composition of the present invention exhibits good low-temperature storage stability and low rotational viscosity, which can reduce the response time of the liquid crystal display.

[0153] Although several exemplary embodiments have been described in detail above, the disclosed embodiments are exemplary and not restrictive, and those skilled in the art will readily recognize that many other modifications, alterations, and / or substitutions are possible in the exemplary embodiments without materially departing from the novelty teachings and advantages of this disclosure. Therefore, all such modifications, alterations, and / or substitutions are intended to be included within the scope of this disclosure as defined by the appended claims.

Claims

1. A negative liquid crystal composition, characterized in that: Contains at least one dielectric negative compound represented by general formula I: Among them, R 11 Indicates an alkyl group with 1-12 carbon atoms or an alkenyl group with 2-12 carbon atoms; R 12 It represents an alkyl group with 1-12 carbon atoms, an alkoxy group with 1-12 carbon atoms, or an alkenyl group with 2-12 carbon atoms; a represents 0 or 1, f represents 0 or 1.

2. The negative liquid crystal composition according to claim 1, characterized in that: It contains at least one dielectric negative compound represented by general formula I; At least one compound represented by general formula II: Among them, R 21 R 22 Each of the above can be independently represented as an alkyl group with 1-12 carbon atoms, an alkoxy group with 1-12 carbon atoms, or an alkenyl group with 2-12 carbon atoms; Z2 represents a CC single bond - or -CH2O-; b represents 0 or 1; At least one compound represented by general formula III: Among them, R 31 R 32 Each of the above can be independently represented as an alkyl group with 1-12 carbon atoms, an alkoxy group with 1-12 carbon atoms, or an alkenyl group with 2-12 carbon atoms; Rings C1, C2, and C3 are each represented independently. and At most one H on the ring can be replaced by F; and at least one of rings C1, C2, and C3 is c represents 0 or 1; d represents 0 or 1; And at least one compound represented by general formula IV: Among them, R 41 R 42 Each of the above can be independently represented as an alkyl group with 1-12 carbon atoms, an alkoxy group with 1-12 carbon atoms, or an alkenyl group with 2-12 carbon atoms; The content of the compound represented by formula I is 1-30% by mass percentage, the content of the compound represented by formula II is 1-40%, the content of the compound represented by formula III is 1-50%, and the content of the compound represented by formula IV is 5-55%.

3. The negative liquid crystal composition according to claim 2, characterized in that: The liquid crystal composition further comprises one or more compounds of general formulas MA to MG: Among them, R M1 R M2 Each of the above can be represented independently as an alkyl group with 1-12 carbon atoms, an alkenyl group with 2-12 carbon atoms, or an alkoxy group with 1-12 carbon atoms; in liquid crystal compounds, the mass content of the compound represented by general formula M is 1-60%.

4. The negative liquid crystal composition according to claim 2, characterized in that: The compound represented by general formula I is selected from one or more compounds in the group consisting of compounds IA to IC: Among them, R 11 R represents an alkyl group with 1-12 carbon atoms or an alkenyl group with 2-12 carbon atoms; 12 It represents an alkyl group with 1-12 carbon atoms, an alkoxy group with 1-12 carbon atoms, or an alkenyl group with 2-12 carbon atoms.

5. The negative liquid crystal composition according to claim 2, characterized in that: The compound represented by general formula III is selected from one or more of the following compounds: Among them, R C1 R C2 Each of the above can be independently represented as an alkyl group with 1-12 carbon atoms, an alkoxy group with 1-12 carbon atoms, or an alkenyl group with 2-12 carbon atoms.

6. The negative liquid crystal composition according to any one of claims 1-5, characterized in that: One or more chiral agents are also added to the liquid crystal compound, and the content of the chiral agent accounts for 0.01-5% of the total mass of the liquid crystal composition.

7. The negative liquid crystal composition according to claim 6, characterized in that: A stabilizer is also added to the liquid crystal mixture, and the stabilizer has a mass percentage content of 0.01-5%.

8. The negative liquid crystal composition according to claim 7, characterized in that: The liquid crystal mixture further includes at least one polymerizable compound, which accounts for 0.001% to 5% of the weight of the liquid crystal composition.

9. The use of the negative liquid crystal composition according to any one of claims 1-8 in the manufacture of a liquid crystal display device.

10. The application according to claim 9, characterized in that: The liquid crystal display device includes liquid crystal display devices in VA, MVA, PVA, PSVA, IPS, and FFS modes.

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