Liquid crystal composition for va-lcd with uv resistance

Abstract

The application discloses a liquid crystal composition with anti-UV performance for VA-LCD, which comprises 3-90% of at least one first component with the structure shown in formula I, 0-60% of at least one second component with the structure shown in formula II, 3-55% of at least one third component with the structure shown in formula III, 2-45% of at least one fourth component with the structure shown in formula IV, 5-60% of at least one fifth component with the structure shown in formula V, 2-35% of at least one sixth component with the structure shown in formula VI and 2-45% of at least one seventh component with the structure shown in formula VII. The liquid crystal composition formed by the components has high refractive index and high anti-UV performance without introducing a large amount of acetylene substances.

Description

Technical Field

[0001] This invention belongs to the field of liquid crystal material technology, and specifically relates to a liquid crystal composition for VA-LCD with UV resistance. Background Technology

[0002] Polymer / liquid crystal composite films were among the first liquid crystal technologies proposed that do not require polarizers. Polymer / liquid crystal composite films include two types: polymer dispersed liquid crystal (PDLC) and polymer network liquid crystal (PNLC).

[0003] Polymer-dispersed liquid crystals (PDLCs) are produced by mixing nematic liquid crystals (LCs) with prepolymers and then polymerizing them under specific conditions. This results in micron-sized liquid crystal droplets uniformly dispersed within a polymer network. The dielectric anisotropy of the liquid crystal molecules is utilized to obtain materials with electro-optical response characteristics. These materials primarily operate between scattering and transparent states and possess a certain grayscale. PDLC films are high-performance film materials combining liquid crystals and polymers. The liquid crystal molecules endow PDLC films with significant electro-optical properties, attracting widespread attention and promising broad application prospects. Compared to traditional display devices, PDLCs offer many advantages, such as eliminating the need for polarizers and alignment layers, simplifying the fabrication process, and facilitating the production of large-area flexible displays. Currently, they are widely used in optical modulators, thermistors and pressure-sensitive devices, electrically controlled glass, light valves, projection displays, e-books, and electronic curtains.

[0004] The relatively high driving voltage of PDLC devices significantly limits their application in high-information-capacity displays. Therefore, substantially reducing the driving voltage of PDLCs has become a key challenge for researchers in this field. It was later discovered that gradually reducing the polymer content in PDLCs, transforming the structure from small liquid crystal droplets dispersed within polymer branches to a structure where liquid crystals exist as a continuous multi-domain structure within a three-dimensional polymer network, effectively creates a new type of display—Polymer Network Liquid Crystal (PNLC). PNLC not only retains the advantages of PDLCs, such as high brightness and large surface area without the need for an alignment layer, but also has a lower driving voltage (5-10V), allowing for large-information-capacity displays driven by ICs. Therefore, PNLC has great development potential in high-brightness projection displays.

[0005] To achieve good dispersion and transparency states, a mixture of polymer-dispersed liquid crystals and polymer-networked liquid crystals is needed. Nematic liquid crystals require a high refractive index, typically greater than 0.2. Currently, to achieve such a high refractive index, a large amount of alkyne needs to be introduced, resulting in a high alkyne content, typically around 50%, which leads to weak UV resistance. Therefore, a liquid crystal mixture with good stability and strong UV resistance is being developed.

[0006] In view of this, the present invention is proposed. Summary of the Invention

[0007] The purpose of this invention is to provide a liquid crystal composition for VA-LCD with UV resistance, which addresses the problems in the prior art by avoiding the introduction of acetylene compounds while ensuring that the liquid crystal composition has a high refractive index, thus significantly improving the UV resistance of the liquid crystal composition.

[0008] To achieve the above objectives, the first aspect of the present invention provides a liquid crystal composition for VA-LCD with UV resistance, the liquid crystal composition comprising 3 to 90% of at least one first component having a structure as shown in Formula I;

[0009] Specifically, Equation I is:

[0010]

[0011] Wherein, R1 is a C1-C6 straight-chain alkyl group, R1' is a C1-C6 straight-chain alkoxy group or a C1-C6 straight-chain alkyl group, and m1 is 0 or 1;

[0012] 0% to 60% of at least one second component having the structure shown in Formula II;

[0013] Specifically, Equation II is as follows:

[0014]

[0015] Wherein, R2 is a C1-C6 straight-chain alkyl group, and R2' is a C1-C6 straight-chain alkoxy group or a C1-C6 straight-chain alkyl group;

[0016] 3% to 55% of at least one third component having the structure shown in Formula III;

[0017] Specifically, Formula III is:

[0018]

[0019] Wherein, R3 is a C1-C6 straight-chain alkyl group, and R3' is a C1-C6 straight-chain alkoxy group or a C1-C6 straight-chain alkyl group;

[0020] 2% to 45% of at least one fourth component having the structure shown in Formula IV;

[0021] Specifically, Equation IV is:

[0022]

[0023] Wherein, R4 is a C1-C6 straight-chain alkyl or alkoxy group, R4' is a C1-C6 straight-chain alkoxy group or a C1-C6 straight-chain alkyl group, or an F substituent; m2 is 0 or 1;

[0024] 5% to 60% of at least one fifth component having the structure shown in Formula V;

[0025] Specifically, Equation V is:

[0026]

[0027] Wherein, R5 is a C1-C6 straight-chain alkyl group, and R5' is a C1-C6 straight-chain alkoxy group or a C1-C6 straight-chain alkyl group;

[0028] 2% to 35% of at least one sixth component having the structure shown in Formula VI;

[0029] Specifically, Equation VI is:

[0030]

[0031] Wherein, R6 is a C1-C6 straight-chain alkyl group, R6' is a C1-C6 straight-chain alkoxy group or a C1-C6 straight-chain alkyl group, and Ra and Rb are H or F respectively;

[0032] 2% to 45% of at least one seventh component having the structure shown in Formula VII;

[0033] Specifically, formula VII is:

[0034]

[0035] Wherein, R7 is a C1-C6 straight-chain alkyl group, R7' is a C1-C6 straight-chain alkoxy group or a C1-C6 straight-chain alkyl group, and Rc and Rd are H or F, respectively.

[0036] In the above scheme, the compound of the first component has a large negative dielectric anisotropy, a moderate refractive index anisotropy Δn value, and a high clearing point, playing an important role in adjusting the refractive index and dielectric anisotropy parameters; the compounds of the second, third, and fifth components have a wide nematic phase temperature range, large refractive index anisotropy, and high viscosity, playing an important role in adjusting the working temperature range and refractive index of the composition; the compound of the fourth component has a relatively large refractive index and dielectric anisotropy, playing an important role in adjusting the refractive index parameter; the compound of the sixth component has a relatively large refractive index and dielectric anisotropy and extremely strong dielectric anisotropy, playing an important role in adjusting the refractive index and threshold voltage parameters; the compound of the seventh component has a large refractive index, playing a certain role in adjusting the refractive index parameter.

[0037] The liquid crystal composition prepared using the above seven components has a high refractive index, excellent UV resistance, and good UV stability, which can fully meet the performance requirements of PDLC for UV and other resistance.

[0038] Specifically, the seven components of the liquid crystal composition, by weight percentage, include:

[0039] 5-70% of the first component having the structure shown in Formula I;

[0040] 0-50% of a second component having the structure shown in Formula II;

[0041] 5-50% of a third component having the structure shown in Formula III;

[0042] 3-40% of a fourth component having the structure shown in Formula IV;

[0043] 5-45% of a fifth component having the structure shown in Formula V;

[0044] 2-30% of a sixth component having the structure shown in Formula VI;

[0045] 2-30% of the seventh component having the structure shown in Formula VII.

[0046] Preferably, the liquid crystal composition for VA-LCD with UV resistance comprises, by weight percentage, the following:

[0047] 8-55% of the first component having the structure shown in Formula I;

[0048] 5-45% of a second component having the structure shown in Formula II;

[0049] 5-40% of a third component having the structure shown in Formula III;

[0050] 4–35% of a fourth component having the structure shown in Formula IV;

[0051] 5-40% of a fifth component having the structure shown in Formula V;

[0052] 2-20% of a sixth component having the structure shown in Formula VI;

[0053] 2-20% of the seventh component having the structure shown in Formula VII.

[0054] Furthermore, in the first component, R1 is a C1-C5 straight-chain alkyl group, R1' is a C1-C5 straight-chain alkoxy group or a C1-C5 straight-chain alkyl group, and m1 is 0.

[0055] Preferably, the first component is selected from compounds with structures as shown in Formula IA or Formula IB;

[0056] Specifically, formula IA is:

[0057]

[0058] Specifically, Equation ⅠB is:

[0059]

[0060] Furthermore, in the second component, R2 is a C1-C5 straight-chain alkyl group, and R2' is a C1-C5 straight-chain alkoxy group or a C1-C5 straight-chain alkyl group.

[0061] Preferably, the second component is a compound with the structure shown in Formula IIA;

[0062] Specifically, Formula IIA is:

[0063]

[0064] Furthermore, in the third component, R3 is a C1-C5 straight-chain alkyl group, and R3' is a C1-C5 straight-chain alkoxy group or a C1-C6 straight-chain alkyl group.

[0065] Preferably, the third component is a compound with a structure selected from compounds with structures such as Formula IIIA, Formula IIIB or Formula IIIC;

[0066] Specifically, Formula IIIA is:

[0067]

[0068] Specifically, Formula IIIB is:

[0069]

[0070] Specifically, Formula IIIC is:

[0071]

[0072] Furthermore, in the fourth component, R6 is a C1-C5 straight-chain alkyl group, R6' is a C1-C5 straight-chain alkoxy group or a C1-C5 straight-chain alkyl group, and Ra and Rb are H or F, respectively.

[0073] Preferably, the fourth component is a compound with a structure selected from compounds with structures such as Formula IVA or Formula IVB;

[0074] The specific form IVA is:

[0075]

[0076] The specific formula IVB is as follows:

[0077]

[0078] Furthermore, in the fifth component, R5 is a C1-C5 straight-chain alkyl group, and R5' is a C1-C5 straight-chain alkoxy group or a C1-C5 straight-chain alkyl group.

[0079] Preferably, the fifth component is a compound with the structure shown in Formula VA;

[0080] Specifically, Equation VA is:

[0081]

[0082] Furthermore, in the sixth component, R6 is a C1-C5 straight-chain alkyl group, R6' is a C1-C5 straight-chain alkoxy group or a C1-C5 straight-chain alkyl group, and Ra and Rb are H or F, respectively;

[0083] Preferably, the sixth component is a compound with a structure selected from compounds with structures such as Formula VIA or Formula VIB;

[0084] Specifically, formula VIA is:

[0085]

[0086] Specifically, Equation VIB is:

[0087]

[0088] Furthermore, in component 7, R7 is a C1-C5 straight-chain alkyl group, R7' is a C1-C5 straight-chain alkoxy group or a C1-C5 straight-chain alkyl group, and Rc and Rd are H or F, respectively;

[0089] Preferably, the seventh component has a structural formula selected from...

[0090] Compounds with structures as shown in Formula VIIA or Formula VIIB;

[0091] Specifically, formula VIIA is:

[0092]

[0093] Specifically, formula VIIB is:

[0094] Detailed Implementation

[0095] Exemplary embodiments of the present invention will be described in more detail below. Those skilled in the art will understand that the following embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0096] It should be noted that the liquid crystal compositions in the following embodiments are prepared using conventional preparation methods in the art, such as thermal dissolution, and therefore will not be described in detail here.

[0097] Example 1

[0098] As an embodiment of the present invention, this embodiment discloses a liquid crystal composition for VA-LCD with UV resistance, specifically comprising the following components:

[0099]

[0100]

[0101] The weight percentage of each component is shown in the table below:

[0102]

[0103] Example 2

[0104] As an embodiment of the present invention, this embodiment discloses a liquid crystal composition for VA-LCD with UV resistance, specifically comprising the following components:

[0105]

[0106]

[0107]

[0108] The weight percentage of each component is shown in the table below:

[0109]

[0110] Example 3

[0111] As an embodiment of the present invention, this embodiment discloses a liquid crystal composition for VA-LCD with UV resistance, specifically comprising the following components:

[0112]

[0113]

[0114]

[0115] The weight percentage of each component is shown in the table below:

[0116]

[0117] Example 4

[0118] As an embodiment of the present invention, this embodiment discloses a liquid crystal composition for VA-LCD with UV resistance, specifically comprising the following components:

[0119]

[0120]

[0121] The weight percentage of each component is shown in the table below:

[0122]

[0123]

[0124] Comparative Example 1

[0125] This comparative example provides a liquid crystal composition, specifically comprising the following components:

[0126]

[0127]

[0128] The weight percentage of each component is shown in the table below:

[0129] structural weight percentage Formula a 8 Formula b 8 Formula c 5 Formula d 2 Formula e 2 Formula f 12 Formula g 7 Formula h 6 Formula i 18 Formula j 16 Formula k 16

[0130] Comparative Example 2

[0131] Comparative Example 2 has a composition and ratio that are basically the same as that of Example 1. The difference is that, in this comparative example, components 6 and 7 are replaced with substances containing alkyne structures, and the amount of each component is adjusted according to its properties. Specifically, it includes the following components:

[0132]

[0133]

[0134] The weight percentage of each component is shown in the table below:

[0135]

[0136] It should be noted that the adjustment of the dosage parameters of each component in this comparative example is only to make the composition in Comparative Example 2 have similar optical properties to the composition provided in Example 1, which is beneficial.

[0137] Experimental Example 1

[0138] The liquid crystal compositions prepared in the above embodiments and comparative examples were subjected to performance tests. The test results and corresponding test conditions are as follows:

[0139] NI: Nematic-Isotropic Phase Transformation Temperature

[0140] η: Bulk viscosity at 20℃

[0141] Δε: 1kHz, 5.5μm vertical box test

[0142] Δn: Optical anisotropy at 20℃, measured at 589nm.

[0143] V90: fdrive=128HZ; Bias=1; Duty=1; VA Cell gap=5.0μm; Test Temperature=23±2℃

[0144] The specific test results are as follows:

[0145] NI (°C) η(mPa·s) Δε Δn V90 Example 1 110 85 -4.8 0.203 2.238 Example 2 95 84 -5.2 0.1935 2.029 Example 3 99 84 -4.8 0.203 2.037 Example 4 92 78 -5.3 0.204 2.141 Comparative Example 1 107 57 -5.8 0.1908 2.0 Comparative Example 2 111 70 -5.2 0.2085 2.186

[0146] Examples 1 to 4 use the composition described in this invention, wherein the introduction of acetylene is avoided. Comparative Example 1 uses a component containing acetylene. As can be seen from the above test results, the properties of the composition described in this invention are similar to those of Comparative Example 1; in particular, Δn in Example 2 can reach 0.1935, which is only 0.0027 different from 0.1908 in Comparative Example 1. This shows that this application can obtain a liquid crystal composition with a high refractive index without introducing acetylene.

[0147] Experimental Example 2

[0148] This experimental example tests the power consumption of the liquid crystal compositions in the above embodiments and comparative examples. The specific test results are as follows:

[0149]

[0150] The power consumption test data for Example 1 and Comparative Example 2 are as follows:

[0151]

[0152] The test results above show that the power consumption of Example 1 during the sealing process is slightly lower than that of Comparative Example 2. After UV exposure, the power consumption of Example 1 is significantly lower than that of Comparative Example 2. In particular, after prolonged UV exposure, the power consumption of Comparative Example 2 increases significantly. This indicates that the liquid crystal composition prepared by the present invention has excellent UV resistance.

[0153] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. The implementation schemes in the above embodiments can also be further combined or replaced. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A liquid crystal composition for VA-LCD with UV resistance, characterized in that, By weight percentage, including: First component: 7% of the compound represented by formula IA and 7% of the compound represented by formula IB; Specifically, formula IA is: Specifically, Equation ⅠB is: The third component consists of 6% of the compound represented by formula IIIA, 6% of the compound represented by formula IIIB, and 6% of the compound represented by formula IIIC; Specifically, Formula IIIA is: Specifically, Formula IIIB is: Specifically, Formula IIIC is: Fourth component: 16% of the compound represented by formula IVA and 15% of the compound represented by formula IVB; The specific form IVA is: The specific formula IVB is as follows: Fifth component: The compound represented by formula VA accounts for 19%; Specifically, Equation VA is: Component 6: 2% of the compound represented by Formula VIA and 2% of the compound represented by Formula VIB; Formula VIA specifically comprises: Specifically, Equation VIB is: Component VII: 7% of the compound represented by Formula VIIA and 7% of the compound represented by Formula VIIB; Formula VIIA specifically comprises: Specifically, formula VIIB is:

2. A liquid crystal composition for VA-LCD with UV resistance, characterized in that, By weight percentage, including: First component: 8% of the compound represented by formula IA and 8% of the compound represented by formula IB; Specifically, formula IA is: Specifically, Equation ⅠB is: Second component: 9% of the compound represented by formula IIA; Specifically, Formula IIA is: The third component consists of 6% of the compound represented by formula IIIA, 6% of the compound represented by formula IIIB, and 6% of the compound represented by formula IIIC; Specifically, Formula IIIA is: Specifically, Formula IIIB is: Specifically, Formula IIIC is: Fourth component: 7% of the compound represented by formula IVA and 7% of the compound represented by formula IVB; specifically, formula IVA is: The specific formula IVB is as follows: Fifth component: The compound represented by formula VA accounts for 21%; Specifically, Equation VA is: Component 6: 3% of the compound represented by Formula VIA and 3% of the compound represented by Formula VIB; Formula VIA specifically comprises: Specifically, Equation VIB is: Component 7: 8% of the compound represented by Formula VIIA and 8% of the compound represented by Formula VIIB; Formula VIIA specifically comprises: Specifically, formula VIIB is:

3. A liquid crystal composition for VA-LCD with UV resistance, characterized in that, By weight percentage, including: First component: 8% of the compound represented by formula IA and 8% of the compound represented by formula IB; Specifically, formula IA is: Specifically, Equation ⅠB is: Second component: 8% of the compound represented by formula IIA; Specifically, Formula IIA is: The third component consists of 7% of the compound represented by formula IIIA, 6% of the compound represented by formula IIIB, and 6% of the compound represented by formula IIIC; Specifically, Formula IIIA is: Specifically, Formula IIIB is: Specifically, Formula IIIC is: Fourth component: 8% of the compound represented by formula IVA, and 9% of the compound represented by formula IVB; specifically, formula IVA is: The specific formula IVB is as follows: Fifth component: 25% of the compound represented by formula VA; Specifically, Equation VA is: Component 6: 4% of the compound represented by Formula VIA and 5% of the compound represented by Formula VIB; specifically, Formula VIA is: Specifically, Equation VIB is: Component 7: 3% of the compound represented by Formula VIIA and 3% of the compound represented by Formula VIIB; Specifically, formula VIIA is: Specifically, formula VIIB is:

4. A liquid crystal composition for VA-LCD with UV resistance, characterized in that, include: First component: 10% of the compound represented by formula IA and 10% of the compound represented by formula IB; Specifically, formula IA is: Specifically, Equation ⅠB is: The third component consists of 14% of the compound represented by formula IIIA, 7% of the compound represented by formula IIIB, and 6% of the compound represented by formula IIIC. Specifically, Formula IIIA is: Specifically, Formula IIIB is: Specifically, Formula IIIC is: Fourth component: 5% of the compound represented by formula IVA, and 7% of the compound represented by formula IVB; specifically, formula IVA is: The specific formula IVB is as follows: Fifth component: 24% of the compound represented by formula VA; Specifically, Equation VA is: Component 6: 5% of the compound represented by Formula VIA and 5% of the compound represented by Formula VIB; specifically, Formula VIA is: Specifically, Equation VIB is: Component 7: 3% of the compound represented by Formula VIIA and 4% of the compound represented by Formula VIIB; Specifically, formula VIIA is: Specifically, formula VIIB is:

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