High dichromatic ratio and high reliability dark color material composition and application thereof

Abstract

The present application relates to the technical field of organic materials, in particular to a high dichromatic ratio and high reliability dark material composition and application thereof. The material composition comprises a microcrystalline composition A and a dichromatic dye, wherein the microcrystalline composition comprises at least one of the compounds of general formula I, the compound of general formula II, the compound of general formula III, the compound of general formula IV, and the compound V and the compound VI. The composition realizes the improvement of the dichromatic ratio through the synergy of the components in the molecular orientation, dye anchoring and thermal stability, is stable under high temperature and high-low temperature cycles, has fast response speed and long service life. The composition can be used for preparing light-adjusting films, is suitable for building intelligent curtain walls, traffic vehicles, high-end displays, security and the like, and solves the problems of low dichromatic ratio and poor stability of the existing materials.

Description

Technical Field

[0001] This invention relates to the field of organic materials technology, and in particular to a high dichroism ratio, high reliability, and dark-colored material composition and its application. Background Technology

[0002] With the rapid development of smart buildings, new energy vehicles, and high-end display industries, the application scenarios of smart dimming films are constantly expanding, from commercial building curtain walls and residential privacy glass to car sunroofs and display polarization components. The market's demand for "high contrast" and "long-term reliability" of dimming films is becoming increasingly stringent. As the core functional layer of dimming films, the performance of the dark material composition directly determines the light-blocking effect and service life of the dimming film. The higher the dichroism ratio (the ratio of the absorbance of parallel polarized light to the absorbance of vertical polarized light), the more significant the contrast between the transparent and light-blocking states of the dimming film; the stronger the stability, the better it can adapt to extreme environments such as high temperature exposure and low temperature, as well as long-term high-frequency use scenarios. At present, the mainstream dark material compositions in the industry are mainly based on traditional biphenyl cyanide liquid crystals (such as 5PPN, 7PPN) and dichroic dyes, but there are still many technical bottlenecks in practical applications, making it difficult to meet the needs of high-end scenarios.

[0003] The primary drawback of existing dark-colored material compositions is their generally low dichroic ratio. The matrix of these materials often relies on biphenyl cyanide or cyclohexylbiphenyl molecules, where molecular order is maintained solely through π-π stacking of benzene rings. This interaction is weak and easily affected by temperature and external forces, resulting in insufficient molecular regularity in the microcrystalline phase. Simultaneously, the compatibility of commonly used dichroic dyes (such as azo and anthraquinone dyes) with the matrix depends only on simple alkyl chain length matching, lacking specific interactions. Dye molecules easily aggregate or diffuse freely within the matrix, failing to achieve "molecular-level" oriented alignment with the microcrystalline material molecules. This disordered state limits the absorption efficiency of parallel polarized light and makes it difficult to reduce the transmittance of vertically polarized light, thus failing to achieve the complete light-blocking privacy protection required for high-end building curtain walls or the high polarization enhancement effect required for display devices.

[0004] Stability defects are another core problem of existing materials, specifically manifested in three aspects: high-temperature tolerance, low-temperature resistance to precipitation, and long-term resistance to degradation. From a molecular structure perspective, existing materials are mostly combinations of pure hydrocarbon chains and benzene rings, lacking rigid heterocyclic structures (such as benzoxazole rings and triazine rings). The long-chain alkyl groups of C and C are prone to thermal expansion at high temperatures, disrupting the material's ordered arrangement and leading to phase stratification and turbidity. At low temperatures, the excessively dense intermolecular packing and lack of flexible adjustment structures make it easy for crystalline phases to precipitate, affecting the uniformity of light transmission. Furthermore, the bonding between dyes and materials relies solely on van der Waals forces, lacking strong polar interactions. After long-term use or high-low temperature cycling, dye molecules easily detach from the material matrix and aggregate, forming visible particulate matter. This not only increases transmittance fluctuations but also further reduces the dichroic ratio and shortens the lifespan of the dimming film.

[0005] Existing materials also have significant shortcomings in response speed. To improve the phase order of materials, some solutions increase the proportion of rigid material components, but this leads to an increase in the viscosity of the material matrix. Under the action of an external field, the resistance to molecular orientation adjustment increases, the response speed slows down, and the fall time and rise time often exceed 10ms, which cannot meet the requirements of "instant sunshade and anti-glare" for car sunroofs or "rapid polarization switching" for display devices.

[0006] In summary, the current shortcomings of dark-colored material compositions in terms of dichroism ratio, stability, response speed, and long-term reliability have become key bottlenecks restricting the expansion of smart dimming films into high-end fields. Developing a dark-colored material composition with high dichroism ratio and high reliability that can solve the above problems simultaneously has significant industrial value and application significance. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and to propose a high dichroism ratio, high reliability dark material composition and its application.

[0008] To achieve the above objectives, the present invention provides a high dichroism ratio and high reliability dark color material composition, wherein the high dichroism ratio and high reliability dark color material composition comprises a microcrystalline composition A and a dichroic dye;

[0009] Microcrystalline composition A contains at least one compound of general formula I:

[0010] ;

[0011] R1 represents a straight-chain alkane containing 3-8 carbon atoms;

[0012] X represents -COO- or -CH2-;

[0013] R2 represents -H, -CH3, -OCH3, -F, monosubstituted, located at the 4th or 6th position of the benzoxazole ring;

[0014] Y represents -CN or -F.

[0015] Preferably, the compounds of general formula I specifically include the following categories of compounds:

[0016] .

[0017] Preferably, to facilitate the representation of the specific type of compound of general formula I, the functional groups and positions in R1 and R2 of compound of general formula I are represented by the following codes, in the order of I-X-R1 code-R2 code, where X=1-8:

[0018] R1: -C3H7-:3, -C4H9-:4, -C5H 11 -:5、-C6H 13 -:6、-C7H 15 -:7、-C8H 17 -:8;

[0019] R2: Located at position 4 of the benzoxazole ring: -H: 4 H, -CH3: 4 C, -OCH3: 4 OC, -F: 4 F;

[0020] Located at position 6 of the benzoxazole ring: -H: 6 H, -CH3: 6 C, -OCH3: 6 OC, -F: 6 F;

[0021] Take the following compound with the following structural formula as an example:

[0022] The compound with this structural formula can be expressed as I-3-6- 6 OC.

[0023] Preferably, the microcrystalline composition A further comprises a compound of general formula II:

[0024] ;

[0025] Where R a This indicates a straight-chain alkane containing 5 or 7 carbon atoms;

[0026] The compounds of general formula II specifically include the following compounds:

[0027] ;

[0028] .

[0029] Preferably, the microcrystalline composition A further comprises a compound of general formula III:

[0030] ;

[0031] Where R b This indicates a straight-chain alkane containing 2, 5, or 8 carbon atoms;

[0032] The compounds of general formula III specifically include the following compounds:

[0033] ;

[0034] ;

[0035] .

[0036] Preferably, the microcrystalline composition A further comprises a compound of general formula IV:

[0037] ;

[0038] Where R C This indicates a straight-chain alkane containing 2-3 carbon atoms;

[0039] Specifically, compounds of general formula IV also include the following compounds:

[0040] ;

[0041] .

[0042] Preferably, the microcrystalline composition A further comprises compound V:

[0043] .

[0044] Preferably, the microcrystalline composition A further comprises compound VI:

[0045] .

[0046] Preferably, the dichroic dye is selected from Mitsui Chemicals DFL-1098.

[0047] Preferably, all the compounds and dichroic dyes described above can be synthesized using known methods or obtained commercially. These synthetic techniques are conventional, and the resulting dye microcrystalline material compositions have been tested and found to meet the standards for electronic compounds.

[0048] Preferably, the weight parts of various compounds and dichroic dyes in the high dichroism ratio, high reliability, and dark color material composition are as follows: Compound I: 3-8 parts, Compound II-1: 15-19 parts, Compound II-2: 11-15 parts, Compound III-1: 8-12 parts, Compound III-2: 6-10 parts, Compound III-3: 8-12 parts, Compound IV-1: 10-14 parts, Compound IV-2: 8-12 parts, Compound V: 8-12 parts, Compound VI: 8-12 parts, and Mitsui Chemicals' DFL-1098: 6-10 parts.

[0049] Preferably, the high dichroism ratio and high reliability dark material composition is mixed, dissolved and filtered, and finally in a liquid state. It is then poured into a 30µm thick antiparallel liquid crystal cell, and the absorbance in the parallel direction A∥ and the absorbance in the vertical direction A⊥ are tested. The ratio of A∥ to A⊥ is greater than 15.

[0050] Furthermore, the present invention also provides the application of a high dichroism ratio, high reliability dark material composition in dimming films.

[0051] Preferably, the mechanism of action of the high dichroism ratio and high reliability dark-colored material composition of the present invention is as follows:

[0052] In this invention, microcrystalline composition A serves as the core matrix (containing compounds of general formulas I, II, III, and IV, as well as compounds V and VI). Through a multi-component synergistic effect with the dichroic dye (DFL-1098), it constructs an ordered system, directionally amplifies dichroism, and comprehensively enhances stability, achieving a "high dichroism ratio and high reliability." The functions and synergistic logic of each component are as follows:

[0053] The ordered nature of the microcrystalline matrix is ​​fundamental to dye orientation and dichroism, and this order relies on the structural adaptation and complementary effects of compounds of general formulas I-IV and V and VI. Compounds of general formula II (R...) a Biphenyl cyanides (C5 / C7 straight-chain alkanes) form the core of the matrix's skeleton. Their biphenyl conjugated structure provides the basic microcrystalline material phase order, while long-chain alkyl groups (C5 / C7) ensure adequate intermolecular spacing and maintain the microcrystalline material's phase fluidity. However, the intermolecular interactions of a single general formula II component rely solely on the π-π stacking of benzene rings, limiting its orientation stability.

[0054] For compounds of general formula I (R1 is a C3-C8 straight-chain alkane containing a benzoxazole ring): the strong conjugation of the benzoxazole heterocycle and the biphenyl structure of compounds of general formula II form a "heterocycle-benzene ring" hyperconjugation effect, which enhances the intermolecular binding force; the variable side chain R1 (C3-C8) can be adjusted according to the long chain (C5 / C7) of compounds of general formula II to optimize the molecular arrangement density and avoid orientation disorder caused by local voids; the polarity difference of the substituents (-H, -CH3, -OCH3, -F) and the flexible adaptation of the X linker (-COO- or -CH2-) further refine the orientation of the microcrystalline material phase and improve the overall order of the matrix;

[0055] Compound of general formula III (R b For C2 / C5 / C8 straight-chain alkanes: the side chain lengths (C2 / C5 / C8) are complementary to those of general formula II compounds (C5 / C7) and general formula I compounds (C3-C8). The short chain (C2) can fill the tiny gaps between long-chain microcrystalline molecules, while the medium and long chains (C5 / C8) form a gradient arrangement with the side chains of general formula II and I compounds, reducing steric hindrance conflicts between molecules, so that the microcrystalline material phase remains uniform and ordered over a wide temperature range, and avoids the precipitation of crystalline phases due to excessive molecular packing at low temperatures;

[0056] Compound of general formula IV (R c It consists of C2-C3 straight-chain alkanes. Short-chain alkyl (C2-C3) molecules have small molecular size and can be intercalated between other long-chain microcrystalline material molecules (such as C7 of general formula II and C8 of general formula I), reducing the overall viscosity of the matrix and improving the molecular response speed under external field, while not destroying the overall order.

[0057] The specific conjugated structures of compounds V and VI can form additional π-π interactions with the benzoxazole ring of compound I and the biphenyl ring of compound II, thereby enhancing the rigidity of the microcrystalline material matrix, preventing the orientation from becoming loose due to excessive stretching of molecular chains at high temperatures, improving the clearing point of the microcrystalline material phase, and widening the operating temperature range.

[0058] The intrinsic dichroic properties of the dichroic dye (DFL-1098) depend on the ordered orientation of the microcrystalline matrix to be fully realized, and the synergistic effect of all components in the microcrystalline composition A provides just the right support for the dye. First, the benzoxazole ring of the compound of general formula I is highly compatible with the conjugated skeleton of the dye, and its terminal polar group Y (-CN or -F) can form specific hydrogen bonds / dipole interactions with the polar functional groups of the dye molecule, tightly "anchoring" the dye molecule to the molecular skeleton of the microcrystalline material, avoiding the free diffusion and aggregation of dyes due to insufficient compatibility in traditional systems; at the same time, the R2 substituents of the compound of general formula I (such as -F, -OCH3, etc.) can adjust the conjugated electron cloud density of the dye through electronic effects, thereby improving the absorption coefficient of the dye for parallel polarized light;

[0059] Secondly, the highly ordered matrix constructed by general formulas II, III, and IV, as well as compounds V and VI, provides guidance for dye orientation: the biphenyl skeleton of general formula II forms the main orientation direction, the gradient side chains of general formula III ensure that dye molecules are uniformly distributed along the main direction, the low viscosity of general formula IV allows the dye to respond quickly to the external field orientation along with the microcrystalline material molecules, and the rigid structure of compounds V and VI fixes the orientation angle of the dye and avoids orientation shift. Finally, the dye molecules achieve ordered arrangement with the microcrystalline material matrix, and polarized light parallel to the orientation direction is largely absorbed by the dye (absorbance A∥ is significantly improved), while polarized light perpendicular to the orientation direction has good light transmittance in the short axis direction of the dye molecules (absorbance A⊥ remains extremely low), causing the A∥ / A⊥ ratio to exceed 15, achieving a substantial improvement in the dichroism ratio.

[0060] The reliability issues of traditional dark-colored material compositions (high-temperature phase separation, dye precipitation, and long-term performance degradation) are resolved through the structural complementarity and synergistic effects of all components in the microcrystalline composition A. From a thermal stability perspective, the benzoxazole heterocyclic decomposition temperature of compound I is >300℃, forming a "high-temperature anti-dispersion skeleton" with the rigid conjugated structures of compounds V and VI, inhibiting the molecular chain extension of compounds II and III at high temperatures. The C2 short chain of compound III and the C2-C3 short chains of compound IV can fill the expanded gaps between long-chain molecules (such as C7 of compound II and C8 of compound I) at high temperatures, preventing phase separation caused by local voids and ensuring the system remains stratified even after long-term storage at high temperatures.

[0061] From the perspective of dye stability, the "anchoring effect" of compound I and the "dispersing effect" of compound III work together: the polar groups of compound I fix the dye molecules, the gradient side chains of compound III prevent the aggregation of dye molecules, and the low viscosity of compound IV reduces the resistance to the movement of dye molecules, so that the system remains free of dye precipitation after low temperature-high temperature cycling.

[0062] From the perspective of long-term chemical stability, the benzoxazole ring of compound I, the biphenyl ring of compound II, and the conjugated structures of compounds V and VI all have excellent resistance to ultraviolet degradation, which can reduce the breaking of chemical bonds under ultraviolet irradiation, greatly improve the continuous working life of dimming film products, and achieve the goal of high reliability.

[0063] The beneficial effects of this invention are:

[0064] 1. This invention introduces a compound of general formula I containing a benzoxazole ring. The heterocycle of this compound forms a strong hyperconjugation with the biphenyl structure of the compound of general formula II, enhancing the intermolecular π-π stacking effect and significantly improving the molecular arrangement regularity of the microcrystalline material matrix. Simultaneously, the polar functional group at the end of general formula I can form a dipole interaction with dichroic dyes, tightly anchoring the dyes and orienting them with the microcrystalline material, preventing dye aggregation. This molecular-level synergy significantly improves the material's absorption efficiency for parallel polarized light while maintaining a low transmittance for vertically polarized light, ultimately achieving a higher dichroism ratio. This meets the high contrast requirements of "high-definition light transmission - complete light blocking" in scenarios such as intelligent curtain walls and high-end displays.

[0065] 2. In the benzoxazole heterocycle of the compound of general formula I of this invention, the CN and CO bonds have high bond energies and excellent thermal stability. They can form a "high-temperature anti-dispersion skeleton" with the conjugated skeleton of compounds V and VI, inhibiting the excessive stretching of long-chain alkyl groups in other microcrystalline material components at high temperatures. The short-chain alkyl groups of general formula III can also fill the gaps between long-chain molecules at high temperatures, avoiding phase separation caused by local voids. This design allows the material to remain in a homogeneous liquid state without stratification or turbidity during long-term use in high-temperature environments, making it suitable for harsh scenarios such as summer exposure to building curtain walls and high temperatures in car sunroofs.

[0066] 3. In this invention, the polar groups of the compound of general formula I can sustainably anchor dye molecules, preventing them from detaching from the microcrystalline material framework due to intensified molecular motion during temperature cycling; the gradient side chains of the compound of general formula III can form a steric hindrance gradient, avoiding dye aggregation at low temperatures and diffusion at high temperatures; the short-chain alkyl groups of the compound of general formula IV reduce matrix viscosity fluctuations and decrease dye movement resistance. These effects collectively ensure that after multiple high and low temperature cycles, the material exhibits no dye precipitation, no crystalline phase sedimentation, and minimal transmittance fluctuations, enabling stable application in extreme climates such as frigid and scorching regions.

[0067] 4. In this invention, the variable side chains of the compound of general formula I can adjust steric hindrance according to the long chain length of other microcrystalline material components, reducing intermolecular obstruction; the short-chain alkyl groups of the compound of general formula IV can intercalate between long-chain molecules, further reducing the viscosity of the microcrystalline material matrix. Simultaneously, the flexible linker group of the compound of general formula I can enhance molecular mobility, enabling molecules to rapidly adjust their orientation under an external field, shortening the switching time from transparent to opaque and vice versa, thus meeting the response speed requirements of applications such as instant sunshade in automobiles and rapid polarization adjustment in display devices.

[0068] 5. The benzoxazole ring of compound I, the biphenyl ring of compound II, and the conjugated structures of compounds V and VI in this invention all possess excellent resistance to UV degradation, reducing the breakage of chemical bonds under UV irradiation. These designs ensure that the dichroism ratio decays slowly and without abrupt performance changes during long-term use, significantly extending the continuous working life of the dimming film and reducing maintenance frequency and costs in high-end applications. Detailed Implementation

[0069] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0070] Example 1: A high dichroism ratio and high reliability dark-colored material composition:

[0071] According to the components and their weights listed in Table 1, the high dichroism ratio and high reliability dark color material composition of Example 1 was prepared by mixing, dissolving and filtering.

[0072] Table 1

[0073]

[0074] Example 2: A high dichroism ratio and high reliability dark-colored material composition:

[0075] According to the components and their weights listed in Table 2, the high dichroism ratio and high reliability dark color material composition of Example 2 was prepared by mixing, dissolving and filtering.

[0076] Table 2

[0077]

[0078] Example 3: A high dichroism ratio and high reliability dark-colored material composition:

[0079] According to the components and their weights listed in Table 3, the high dichroism ratio and high reliability dark color material composition of Example 3 was prepared by mixing, dissolving and filtering.

[0080] Table 3

[0081]

[0082] Example 4: A high dichroism ratio and high reliability dark-colored material composition:

[0083] According to the components and their weights listed in Table 4, the high dichroism ratio and high reliability dark color material composition of Example 4 was prepared by mixing, dissolving and filtering.

[0084] Table 4

[0085]

[0086] Example 5: A high dichroism ratio and high reliability dark-colored material composition:

[0087] According to the components and their weights listed in Table 5, the high dichroism ratio and high reliability dark material composition of Example 5 was prepared by mixing, dissolving and filtering.

[0088] Table 5

[0089]

[0090] Example 6: A high dichroism ratio and high reliability dark-colored material composition:

[0091] According to the components and their weights listed in Table 6, the high dichroism ratio and high reliability dark color material composition of Example 6 was prepared by mixing, dissolving and filtering.

[0092] Table 6

[0093]

[0094] Example 7: A high dichroism ratio and high reliability dark-colored material composition:

[0095] According to the components and their weights listed in Table 7, the high dichroism ratio and high reliability dark color material composition of Example 7 was prepared by mixing, dissolving and filtering.

[0096] Table 7

[0097]

[0098] Example 8: A high dichroism ratio and high reliability dark-colored material composition:

[0099] According to the components and their weights listed in Table 8, the high dichroism ratio and high reliability dark color material composition of Example 8 was prepared by mixing, dissolving and filtering.

[0100] Table 8

[0101]

[0102] Example 9: A high dichroism ratio and high reliability dark-colored material composition:

[0103] According to the components and their weights listed in Table 9, the high dichroism ratio and high reliability dark color material composition of Example 9 was prepared by mixing, dissolving and filtering.

[0104] Table 9

[0105]

[0106] Example 10: A high dichroism ratio and high reliability dark-colored material composition:

[0107] According to the components and their weights listed in Table 10, the high dichroism ratio and high reliability dark color material composition of Example 10 was prepared by mixing, dissolving and filtering.

[0108] Table 10

[0109]

[0110] Example 11: A high dichroism ratio and high reliability dark-colored material composition:

[0111] According to the components and their weights listed in Table 11, the high dichroism ratio and high reliability dark color material composition of Example 11 was prepared by mixing, dissolving and filtering.

[0112] Table 11

[0113]

[0114] Example 12: A high dichroism ratio and high reliability dark-colored material composition:

[0115] According to the components and their weights listed in Table 12, the high dichroism ratio and high reliability dark color material composition of Example 12 was prepared by mixing, dissolving and filtering.

[0116] Table 12

[0117]

[0118] Comparative Example 1: The difference between Comparative Example 1 and Example 2 is that Comparative Example 1 does not contain I-1-3- 4 OC, Ⅰ-1-7- 6 C and I-2-4- 6 H.

[0119] Comparative Example 2: The difference between Comparative Example 2 and Example 2 is that: I-1-3- was added. 4 OC, Ⅰ-1-7- 6 C and I-2-4- 6 The total mass of H is 10g.

[0120] Comparative Example 3: The difference between Comparative Example 3 and Example 2 is that: I-1-3- was added. 4 OC, Ⅰ-1-7- 6 C and I-2-4- 6 The total mass of H is 100g.

[0121] Performance testing:

[0122] Test sample preparation: The compositions of Examples 1-12 and Comparative Examples 1-3 were prepared into homogeneous liquids by mixing, dissolving and filtering. They were injected into 30μm thick antiparallel liquid crystal cells (ITO conductive glass, polyimide alignment layer, antiparallel friction direction) using vacuum injection method. After sealing the injection port, the samples were annealed at 60℃ for 2 hours and then allowed to cool naturally to room temperature for later use.

[0123] 1. Dichroism Ratio Test: The testing equipment used was a UV-Vis spectrophotometer (wavelength range 380-780nm, accuracy ±0.001Abs). The testing environment was controlled at 25℃ and 50% relative humidity. During the test, the liquid crystal cell was fixed on the sample stage. First, the polarization direction of the incident light was aligned with the molecular orientation direction of the microcrystalline material, and the absorbance A∥ in the wavelength range of 380-780nm was scanned and recorded. Then, the sample stage was rotated 90° so that the polarization direction of the incident light was perpendicular to the molecular orientation direction of the microcrystalline material, and the absorbance A⊥ was scanned and recorded again. At the maximum absorption wavelength of the sample, the dichroism ratio was calculated based on the ratio of A∥ to A⊥ at this time. The experimental results are shown in Table 13.

[0124] 2. High-Temperature Stability Test: Take the prepared test samples and place them in a constant temperature chamber at 60℃ for 1000 hours. Every 200 hours, take out the samples, equilibrate them at 25℃ for 1 hour, and then measure the dichroism ratio at the maximum absorption wavelength using the same method as the dichroism ratio test. Record the rate of change. Simultaneously, observe whether the samples exhibit phase separation, turbidity, or visible particulate matter. After the test, calculate the dichroism ratio decay rate (decay rate = (initial value - value after 1000 hours) / initial value × 100%), and record the appearance of the samples. The experimental results are shown in Table 13.

[0125] 3. High and Low Temperature Cyclic Stability Test: Each test sample was placed in a high and low temperature test chamber, and the cycling program was set as follows: -40℃ constant temperature for 2 hours → heating to 120℃ (heating rate 5℃ / min) → 120℃ constant temperature for 2 hours → cooling to -40℃ (cooling rate 5℃ / min), completing one cycle, and a total of 100 cycles were performed. After the cycle, the samples were equilibrated at 25℃ for 4 hours. First, it was observed whether there was dye precipitation, crystal phase precipitation, or phase separation in the liquid crystal cell; then, the dichroism ratio at the maximum absorption wavelength was measured according to the dichroism ratio test method, and compared with the initial dichroism ratio to calculate the attenuation rate. At the same time, the transmittance of the sample in the transparent state and the transmittance in the shading state were measured using a transmittance meter, and the transmittance fluctuation value was recorded (fluctuation value = |value after cycle - initial value|). The experimental results are shown in Table 13.

[0126] 4. Response Speed ​​Test: Each test sample was connected to a programmable DC power supply. The test environment was 25℃, and the electric field strength was set to 10V / μm. The transmittance change of the sample during the switching process of "electric field on (blocked state) - electric field off (transparent state)" was monitored in real time using a transmittance meter. When the electric field was on, the time it took for the transmittance to drop from 85% to below 0.5% (fall time) was recorded; when the electric field was off, the time it took for the transmittance to rise from below 0.5% to 85% (rise time) was recorded. The experimental results are shown in Table 13.

[0127] Table 13 Performance Test Results

[0128]

[0129] Performance Analysis:

[0130] As can be seen from the performance test results in Table 13, all embodiments are significantly better than the comparative examples in terms of dichroism ratio, high temperature stability, high and low temperature cycling stability and response speed. All performance indicators can meet the design goals of high dichroism ratio and high reliability. This is due to the synergistic effect of each component in microcrystalline composition A, especially the compatibility of the general formula I compound with other components in terms of molecular structure and interaction, which together construct an ordered, stable and responsive material system.

[0131] The superior color ratio performance of the two-color dyes in Example 1 is due to the strong hyperconjugation between the benzoxazole heterocycle of Formula I and the biphenyl structure of Formula II. The nitrogen and oxygen atoms in the heterocycle enhance the electron delocalization ability of the molecular conjugation system and strengthen the intermolecular π-π stacking effect, which greatly improves the regularity of the molecular arrangement of the microcrystalline material matrix. At the same time, the Y functional group (-CN or -F) at the end of Formula I has strong electronegativity and can form a dipole-dipole interaction with the polar group in the dichroic dye DFL-1098 molecule, which tightly anchors the dye molecule to the molecular backbone of the microcrystalline material, preventing the dye molecule from freely diffusing and aggregating, and ensuring that the dye achieves a highly oriented arrangement with the microcrystalline material molecules. This directional arrangement significantly improves the dye's absorption efficiency for polarized light parallel to the orientation direction, while maintaining a low level of absorption for polarized light perpendicular to the orientation direction, ultimately achieving a higher dichroism ratio. Comparative Example 1, lacking the superconjugation effect of the benzoxazole heterocycle and the anchoring effect of the polar functional groups, relies solely on the weak π-π interaction of the benzene ring between the microcrystalline matrix molecules, resulting in insufficient regularity of arrangement, easy aggregation of dye molecules, and a significantly lower dichroism ratio. In Comparative Example 2, the amount of the introduced Formula I compound is relatively small, resulting in weaker superconjugation and anchoring effects. The orderliness of the microcrystalline material and the orientation of the dye are both inferior to those of the examples, and the dichroism ratio is poor. In Comparative Example 3, the amount of the introduced Formula I compound is excessive. The rigid structure of the benzoxazole heterocycle and the steric hindrance of the long-chain alkyl group cause repulsion between molecules, leading to a decrease in the compatibility of the microcrystalline matrix, local disorder in molecular arrangement, and impact on dye orientation. The dichroism ratio also fails to reach the level of the examples.

[0132] The examples maintain good stability even at high temperatures, primarily due to the excellent thermal stability of the benzoxazole heterocycle in Formula I. The CN and CO bonds in the heterocycle have high bond energies, resulting in a decomposition temperature far exceeding the operating temperature. Its rigid structure forms a "high-temperature anti-dispersion skeleton" with the conjugated skeletons of compounds V and VI, effectively inhibiting excessive stretching and chain slippage of the long-chain alkyl groups in Formulas II and III at high temperatures. Simultaneously, the C2 short-chain alkyl group in Formula III fills the expanded gaps between long-chain molecules (such as C7 in Formula II and C8 in Formula I) at high temperatures, preventing the formation of local voids and inhibiting phase separation. Furthermore, the R2 substituents (such as -F, -OCH3, etc.) in Formula I enhance intermolecular electrostatic interactions through electronic effects, further... To maintain the uniformity of the microcrystalline material phase, the examples showed no stratification or turbidity after high temperature, and the dichroism ratio decay was lower. Comparative Example 1 did not add compound of general formula I, lacking a "high-temperature anti-dispersion framework" and interstitial filling effect. The long-chain alkyl groups of compounds of general formula II and III tend to expand at high temperatures, weakening intermolecular forces and leading to phase stratification and turbidity, resulting in a larger dichroism ratio decay. In Comparative Example 2, the amount of compound of general formula I was less, resulting in insufficient strength of the "high-temperature anti-dispersion framework" and inability to completely suppress the expansion of long-chain molecules, leading to slight turbidity and a higher dichroism ratio decay than the examples. In Comparative Example 3, the amount of compound of general formula I was excessive, and the repulsive effect of the rigid intermolecular structure made the microcrystalline material matrix more prone to local disorder at high temperatures, resulting in severe turbidity and a significantly higher dichroism ratio decay than the examples.

[0133] The embodiments maintained good performance after high and low temperature cycling, thanks to the synergistic effect of the compound of general formula I and other components: the benzoxazole ring of the compound of general formula I has a high degree of matching with the conjugated skeleton of the dye molecule, and its polar groups can continuously anchor the dye molecule, preventing the dye from detaching from the microcrystalline material skeleton due to increased molecular motion during temperature cycling; the gradient side chains (C2 / C5 / C8) of the compound of general formula III can form a steric gradient, preventing the dye molecule from agglomerating due to molecular stacking at low temperatures, while maintaining an appropriate spacing between molecules at high temperatures; the C2-C3 short-chain alkyl molecules of the compound of general formula IV are small in size and can be interspersed between long-chain molecules, reducing the viscosity fluctuation of the microcrystalline material matrix during temperature changes and reducing the resistance to the movement of dye molecules. These effects collectively ensure that no dye precipitation or crystalline phase sedimentation occurs after cycling in the examples, and the transmittance fluctuation is small. In Comparative Example 1, no compound of formula I was added, and the dye molecules lacked effective anchoring. During temperature cycling, they easily detached from the microcrystalline material framework with molecular motion and aggregated and precipitated. At the same time, the viscosity of the microcrystalline material matrix fluctuated greatly under temperature changes, and the transmittance fluctuation was significantly greater than that in the examples. In Comparative Example 2, the amount of compound of formula I was introduced was small, and the dye anchoring and dispersion effect was weak. A small amount of dye precipitation occurred after cycling, and the transmittance fluctuation was higher than that in the examples. In Comparative Example 3, the amount of compound of formula I was introduced was too large. The intermolecular repulsion made the system more prone to turbidity during temperature cycling, and the transmittance fluctuation was also significantly higher than that in the examples.

[0134] The faster response speed of the embodiments is mainly due to the fact that the variable side chains (C3-C8) of the general formula I compound can adjust the steric hindrance according to the long chain length (C5 / C7) of the general formula II compound, reducing the mutual obstruction between microcrystalline material molecules; at the same time, the small size of the C2-C3 short-chain alkyl molecules of the general formula IV compound allows them to intercalate between the long chains of general formula I, II, and III compounds, further reducing the overall viscosity of the microcrystalline material matrix and reducing the resistance to molecular motion under external field; in addition, the X linker group (-COO- or -CH2-) of the general formula I compound has a certain degree of flexibility, which can enhance the mobility of microcrystalline material molecules, allowing the molecules to move more freely in an electric field. Under the influence of the field, the orientation can be quickly adjusted, thereby shortening the descent and ascent times. In Comparative Example 1, no compound of general formula I was added, and the microcrystalline material matrix relied solely on the interaction of compounds of general formulas II, III, and IV. The viscosity was high, the molecular motion resistance was large, and the response speed was significantly slower than that of the example. In Comparative Example 2, the amount of compound of general formula I was small, and the effect on reducing viscosity was limited. The viscosity of the microcrystalline material matrix was still higher than that of the example, and the response speed was slow. In Comparative Example 3, the amount of compound of general formula I was excessive. The repulsive effect of the rigid structure and steric hindrance between molecules significantly increased the viscosity of the microcrystalline material matrix, further increased the molecular motion resistance, and made the response speed even slower.

[0135] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high dichroism ratio and high reliability dark-colored material composition, characterized in that, The high dichroism ratio and high reliability dark material composition comprises a microcrystalline composition A and a dichroic dye; Microcrystalline composition A contains at least one compound of general formula I: ； R1 represents a straight-chain alkane containing 3-8 carbon atoms; X represents -COO- or -CH2-; R2 represents -H, -CH3, -OCH3, -F, monosubstituted, located at the 4th or 6th position of the benzoxazole ring; Y represents -CN or -F; The microcrystalline composition A further comprises a compound of general formula II: ； Where R a This indicates a straight-chain alkane containing 5 or 7 carbon atoms; The microcrystalline composition A further comprises a compound of general formula III: ； Where R b This indicates a straight-chain alkane containing 2, 5, or 8 carbon atoms; The microcrystalline composition A further comprises a compound of general formula IV: ； Where R C This indicates a straight-chain alkane containing 2-3 carbon atoms; The microcrystalline composition A further comprises compound V: ； The microcrystalline composition A further comprises compound VI: 。 2. The high dichroism ratio and high reliability dark-colored material composition according to claim 1, characterized in that, The compounds of general formula II specifically include the following compounds: ； 。 3. The high dichroism ratio and high reliability dark-colored material composition according to claim 2, characterized in that, The compounds of general formula III specifically include the following compounds: ； ； 。 4. The high dichroism ratio and high reliability dark-colored material composition according to claim 3, characterized in that, The compounds of general formula IV specifically include the following compounds: ； 。 5. The high dichroism ratio and high reliability dark-colored material composition according to claim 4, characterized in that, The dichroic dye was selected from Mitsui Chemicals DFL-1098.

6. The high dichroism ratio and high reliability dark-colored material composition according to claim 5, characterized in that, The weight parts of various compounds and dichroic dyes in the high dichroism ratio, high reliability, and dark color material composition are as follows: Compound I: 3-8 parts, Compound II-1: 15-19 parts, Compound II-2: 11-15 parts, Compound III-1: 8-12 parts, Compound III-2: 6-10 parts, Compound III-3: 8-12 parts, Compound IV-1: 10-14 parts, Compound IV-2: 8-12 parts, Compound V: 8-12 parts, Compound VI: 8-12 parts, and Mitsui Chemicals' DFL-1098: 6-10 parts.

7. The high dichroism ratio and high reliability dark-colored material composition according to claim 1, characterized in that, The high dichroism ratio and high reliability dark material composition is mixed, dissolved and filtered, and finally in liquid state. It is then poured into a 30um thick antiparallel liquid crystal cell, and the absorbance in the parallel direction A∥ and the absorbance in the vertical direction A⊥ are tested. The ratio of A∥ to A⊥ is greater than 15.

8. The use of the high dichroism ratio, high reliability dark material composition according to any one of claims 1-7 in dimming films.

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