Applications of a gray dye composition and a dye liquid crystal composition comprising the same

Abstract

The present invention provides a gray dye composition and a dye liquid crystal composition comprising the composition, wherein the dye liquid crystal composition has uniform total absorption in the visible light region, exhibits high contrast when applied in light valves, switchable windows, switchable mirrors and host-guest displays, and has good photothermal stability.

Description

Technical Field

[0001] This invention relates to a gray dye composition, a dye liquid crystal composition comprising the same, and its application in light valves, switchable windows, switchable mirrors, and host-guest displays. Background Technology

[0002] Dye-based liquid crystals are guest-host type liquid crystal materials composed of a host liquid crystal doped with a small amount of guest dichroic dyes. Due to the interaction between the host and guest molecules, the dichroic dye molecules align in an ordered manner following the host liquid crystal molecules. Therefore, by changing the applied electric field, the alignment of the host liquid crystal can be altered, thereby changing the alignment direction of the dye molecules. Dichroic dyes are dye compounds with different light absorption intensities along different axes. Therefore, when they change direction following the rotation of the host liquid crystal molecules, their light absorption capacity also changes, thus achieving the effect of regulating light transmittance. By adding different colored dichroic dyes, liquid crystal devices can display different colors, enabling the modulation of different wavelengths of visible light.

[0003] Compared to traditional liquid crystal devices, this technology does not require polarizing plates, thus achieving higher light utilization. In recent years, with people's continuous pursuit of a higher quality of life, the application fields of dye-based liquid crystals have been constantly expanding. Examples include color-changing sunroofs in automobiles, color-changing glass inside and outside buildings, color-changing side windows on large public transportation vehicles, and smart glasses that change color according to the intensity of external light—all emerging application scenarios for dye-based liquid crystals. Compared to the application scenarios of traditional liquid crystal materials, dye-based liquid crystals have a wider range of applications in large-size devices, many of which are emerging fields, resulting in greater demand and broader application prospects. In most application scenarios, dye-based liquid crystals need to exhibit a near-black color in the dark state to achieve comprehensive absorption of visible light. However, due to the limitations of the molecular structure of dye compounds, it is difficult for a single dye to achieve a black or gray effect with complete absorption of the visible light range.

[0004] Common dichroic dyes include anthraquinone and azo dyes. Anthraquinone dichroic dyes have the advantages of bright colors and good stability, but their disadvantages are relatively weak absorption and poor solubility. Azo dyes have the advantages of strong absorption and strong dichroic contrast, but their disadvantages are poor photostability. There are also other types of dichroic dyes, such as dichroic dyes based on benzothiophene, whose properties are often between those of anthraquinone and azo dyes.

[0005] In summary, each type of dye has its own advantages and disadvantages. It is necessary to skillfully combine dyes of different types and absorption bands to obtain a dye combination that absorbs the entire visible light spectrum, while having good contrast and good photothermal stability to achieve a black or gray effect. Summary of the Invention

[0006] Purpose of the invention: The main purpose of this invention is to provide a gray dye composition and a dye liquid crystal composition containing the composition. The dye liquid crystal composition has uniform total absorption in the visible light region, and has high contrast when applied to light valves, switchable windows, switchable mirrors and host-guest displays, and has good photothermal stability.

[0007] Technical solution: To achieve the above objective, the present invention provides a gray dye composition, characterized in that the dye composition comprises dichroic dyes of components I to III.

[0008] Component I is selected from dichroic dyes represented by formulas I1 to I7, which are as follows:

[0009]

[0010] Wherein, R1, R1', R2 and R2' are each independently H, an alkyl group having 1 to 10 carbon atoms, and an alkoxy group having 1 to 10 carbon atoms, wherein the alkyl group and alkoxy group are straight-chain or branched alkyl and alkoxy groups;

[0011] Component II is selected from dichroic dyes represented by formulas II1 to II20, which are as follows:

[0012]

[0013]

[0014]

[0015] Wherein, R3, R4 and R4' are each independently H, an alkyl group having 1 to 10 carbon atoms, and an alkoxy group having 1 to 10 carbon atoms, wherein the alkyl group and alkoxy group are straight-chain or branched alkyl and alkoxy groups;

[0016] Component III is selected from dichroic dyes represented by formulas III1 to III20, as follows:

[0017]

[0018]

[0019] Wherein, R5, R5', R6 and R6' are each independently H, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms, wherein the alkyl group and alkoxy group are straight-chain or branched alkyl and alkoxy groups.

[0020] In one embodiment of the present invention, a gray dye composition is provided, wherein the mass fraction of component I is 15-60%, the mass fraction of component II is 0-65%, and the mass fraction of component III is 0-45%.

[0021] In another embodiment of the present invention, a gray dye liquid crystal composition is also provided, characterized in that the gray dye liquid crystal composition is composed of the above-mentioned gray dye composition and liquid crystal composition, wherein the gray dye composition accounts for 0.5% to 10% of the mass fraction of the gray dye liquid crystal composition.

[0022] In another embodiment of the present invention, a gray dye liquid crystal composition is also provided, wherein the liquid crystal composition is partially composed of liquid crystal compounds of formulas A1 to A7, wherein formulas A1 to A7 are as follows:

[0023]

[0024] R7 and R8 are each independently selected from alkyl groups having 1 to 7 carbon atoms, alkoxy groups having 1 to 7 carbon atoms, alkenyl groups having 2 to 7 carbon atoms, enalkoxy groups having 2 to 7 carbon atoms, alkyl halogenates having 1 to 7 carbon atoms, alkoxy halogenates having 1 to 7 carbon atoms, alkenyl halogenates having 2 to 7 carbon atoms, enalkoxy halogenates having 2 to 7 carbon atoms, cyclopentyl groups, or cyclopentyl groups substituted with alkyl groups having 1 to 7 carbon atoms, alkoxy groups having 1 to 7 carbon atoms, alkenyl groups having 2 to 7 carbon atoms, or enalkoxy groups having 2 to 7 carbon atoms; wherein the alkyl group, the alkoxy group, the alkenyl group, and the enalkoxy group are straight-chain or branched alkyl groups, alkoxy groups, alkenyl groups, and enalkoxy groups. Detailed Implementation

[0025] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0026] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0027] To address the aforementioned problems, in a typical embodiment of the present invention, a gray dye composition is provided, characterized in that the dye composition comprises dichroic dyes of components I to III.

[0028] Component I is selected from dichroic dyes represented by formulas I1 to I7, which are as follows:

[0029]

[0030]

[0031] Wherein, R1, R1', R2 and R2' are each independently H, an alkyl group having 1 to 10 carbon atoms, and an alkoxy group having 1 to 10 carbon atoms, wherein the alkyl group and alkoxy group are straight-chain or branched alkyl and alkoxy groups;

[0032] Component II is selected from dichroic dyes represented by formulas II1 to II20, which are as follows:

[0033]

[0034]

[0035]

[0036] Wherein, R3, R4 and R4' are each independently H, an alkyl group having 1 to 10 carbon atoms, and an alkoxy group having 1 to 10 carbon atoms, wherein the alkyl group and alkoxy group are straight-chain or branched alkyl and alkoxy groups;

[0037] Component III is selected from dichroic dyes represented by formulas III1 to III20, as follows:

[0038]

[0039]

[0040] Wherein, R5, R5', R6 and R6' are each independently H, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms, wherein the alkyl group and alkoxy group are straight-chain or branched alkyl and alkoxy groups.

[0041] In one embodiment of the present invention, a gray dye composition is provided, wherein the mass fraction of component I is 15-60%, the mass fraction of component II is 0-65%, and the mass fraction of component III is 0-45%.

[0042] In another embodiment of the present invention, a gray dye liquid crystal composition is also provided, characterized in that the gray dye liquid crystal composition is composed of the above-mentioned gray dye composition and liquid crystal composition, wherein the gray dye composition accounts for 0.5% to 10% of the mass fraction of the gray dye liquid crystal composition.

[0043] Component I is an anthraquinone dye, which has the advantages of bright color and strong stability. When used in a dye liquid crystal composition, it can also act as a light stabilizer, which is beneficial to improving the overall stability. Component II is an azo dye, which has the advantages of strong absorption capacity and good dichroism, which is beneficial to improving contrast. Component III is a dichroic dye with benzothiophene as the main component. Its absorption capacity is usually stronger than that of anthraquinone dyes, and it has good dichroism and stability.

[0044] In another embodiment of the present invention, a gray dye liquid crystal composition is also provided, wherein the liquid crystal composition is partially composed of liquid crystal compounds of formulas A1 to A7, wherein formulas A1 to A7 are as follows:

[0045]

[0046] R7 and R8 are each independently selected from alkyl groups having 1 to 7 carbon atoms, alkoxy groups having 1 to 7 carbon atoms, alkenyl groups having 2 to 7 carbon atoms, enalkoxy groups having 2 to 7 carbon atoms, alkyl halogenates having 1 to 7 carbon atoms, alkoxy halogenates having 1 to 7 carbon atoms, alkenyl halogenates having 2 to 7 carbon atoms, enalkoxy halogenates having 2 to 7 carbon atoms, cyclopentyl groups, or cyclopentyl groups substituted with alkyl groups having 1 to 7 carbon atoms, alkoxy groups having 1 to 7 carbon atoms, alkenyl groups having 2 to 7 carbon atoms, or enalkoxy groups having 2 to 7 carbon atoms; wherein the alkyl group, the alkoxy group, the alkenyl group, and the enalkoxy group are straight-chain or branched alkyl groups, alkoxy groups, alkenyl groups, and enalkoxy groups.

[0047] In another embodiment of the present invention, a gray dye liquid crystal composition is provided, wherein the liquid crystal composition comprises, by mass fraction, 10-30% of a liquid crystal compound having formula A1, 1-20% of a liquid crystal compound having formula A2, 20-40% of a liquid crystal compound having formula A3, 5-25% of a liquid crystal compound having formula A4, 5-25% of a liquid crystal compound having formula A5, 10-30% of a liquid crystal compound having formula A6, and 10-30% of a liquid crystal compound having formula A7, wherein the mass fraction is the mass fraction of the liquid crystal compounds of formulas A1 to A7 relative to the liquid crystal composition portion.

[0048] In another embodiment of the present invention, a gray dye liquid crystal composition is provided, the gray dye liquid crystal composition further comprising a chiral agent in a mass fraction of 0 to 20% and a stabilizer in a mass fraction of 0 to 20%.

[0049] The chiral agent is selected from one or more of the following chiral agents:

[0050]

[0051]

[0052] The stabilizer is selected from one or more of the following stabilizers:

[0053]

[0054] Wherein, Y5 is selected from H, F, alkyl groups having 1 to 7 carbon atoms, alkoxy groups having 1 to 7 carbon atoms, alkenyl groups having 2 to 7 carbon atoms, enalkoxy groups having 2 to 7 carbon atoms, alkyl halogenates having 1 to 7 carbon atoms, alkoxy halogenates having 1 to 7 carbon atoms, alkenyl halogenates having 2 to 7 carbon atoms, enalkoxy halogenates having 2 to 7 carbon atoms, cyclopentyl groups, or cyclopentyl groups substituted with alkyl groups having 1 to 7 carbon atoms, alkoxy groups having 1 to 7 carbon atoms, alkenyl groups having 2 to 7 carbon atoms, or enalkoxy groups having 2 to 7 carbon atoms; wherein the alkyl group, the alkoxy group, the alkenyl group, and the enalkoxy group are straight-chain or branched alkyl groups, alkoxy groups, alkenyl groups, and enalkoxy groups.

[0055] In another embodiment of the present invention, the application of the above-described gray dye composition in light valves, switchable windows, switchable mirrors, and guest-host type displays is provided.

[0056] In another embodiment of the present invention, the application of the above-described gray dye liquid crystal composition in light valves, switchable windows, switchable mirrors, and guest-host type displays is provided.

[0057] The gray dye liquid crystal composition provided by this invention can be prepared by conventional methods. Typically, solutions of the components are mixed with an organic solvent, such as acetone, chloroform, or dichloromethane, and after thorough mixing, the solvent is removed again, for example by distillation.

[0058] The method for preparing the test unit of the gray dye liquid crystal composition provided by the present invention involves drawing the dissolved gray dye liquid crystal composition into a horizontally oriented antiparallel liquid crystal cell via capillary action. The thickness of the liquid crystal cell is 3-20 μm.

[0059] In a typical embodiment of the present invention, the thickness of the gray dye liquid crystal composition layer is 9 μm.

[0060] The beneficial effects of the present invention will be further illustrated below with reference to embodiments.

[0061] The following examples are for illustrative purposes only and not for limiting the invention. All percentages mentioned in the examples are by mass, and temperatures are expressed in degrees Celsius. The measured physicochemical parameters are expressed as follows: T NIThe point of illumination is indicated by Δn; Δn represents optical anisotropy (Δn = n). e -n o 589nm, measured at 25℃); Δε represents dielectric anisotropy (Δε=ε ∥ -ε ⊥ (25℃); K 11 K represents the elastic modulus of the stretch curve (measured at 25°C). 33 Indicates the bending elastic modulus (measured at 25°C); τ 亮 Indicates the transmittance in the bright state (the bright state is defined as when the driving voltage is 0V); τ 暗 CR represents dark-state transmittance (dark state is defined as a driving voltage of 48V); CR represents contrast ratio, where CR = τ. 亮 / τ 暗 CIE x, y, L, a, b represent degrees, and colorimetry uses the CIE 1931 standard colorimetric system. Furthermore, DSC is used to measure T. NI Δn was measured using an Abbe refractometer; Δε and K were measured using CV. 11 and K 33 The test unit for the dye-liquid crystal composition was driven by a digital synthesized function signal generator with a driving voltage of 0–48V and a square wave waveform. The thickness of the dye-liquid crystal composition layer in the test unit was 9 μm. A haze meter was used to measure τ. 亮 and τ 暗 The color coordinates were determined using a spectrophotometer.

[0062] In various embodiments of the present invention, the liquid crystal molecule backbone is named as: cyclohexyl Represented by the letter C; phenyl Represented by the letter P; the phenyl group on the left is monofluorinated. Represented by the letter H2, the phenyl group on the right side is monofluorinated. Represented by the letter H1; the corresponding codes for specific group structures are shown in Table 1:

[0063] Table 1

[0064]

[0065]

[0066] The side chains of each compound are converted into chemical formulas according to Table 2 below, with the left-side branch denoted by R1 and the right-side branch by R2. Among them, the group C... n H 2n+1 and C m H 2m+1 They are straight-chain alkyl groups having n and m carbon atoms respectively, and Cp represents cyclopentyl. C n H 2n+1Cp represents a cyclopentyl alkyl group with n carbon atoms in a straight chain. The main chain and branches, as well as the branches themselves, are separated by a hyphen ("-"). In naming, the main chain comes first, followed by the branch. For example, Represented as CMPP-2-N; Represented as CPP-3-N, Represented as PH1P-3-N; It is represented by CC-3-V.

[0067] Table 2

[0068]

[0069]

[0070] Examples of dye compositions

[0071] Example G1

[0072] The dye composition of Example G1 is shown in Table 3.

[0073] Table 3

[0074]

[0075] Example G2

[0076] The dye composition of Example G2 is shown in Table 4.

[0077] Table 4

[0078]

[0079] Example G3

[0080] The dye composition of Example G3 is shown in Table 5.

[0081] Table 5

[0082]

[0083]

[0084] Example G4

[0085] The dye composition of Example G4 is shown in Table 6.

[0086]

[0087]

[0088] Example G5

[0089] The dye composition of Example G5 is shown in Table 7.

[0090] Table 7

[0091]

[0092]

[0093] Example G6

[0094] The dye composition of Example G6 is shown in Table 8.

[0095] Table 8

[0096]

[0097]

[0098] Example G7

[0099] The dye composition of Example G7 is shown in Table 9.

[0100] Table 9

[0101]

[0102]

[0103] Examples of parent liquid crystal compositions

[0104] Example H1

[0105] The composition and measurement parameters of the liquid crystal composition in Example H1 are shown in Table 10.

[0106] Table 10

[0107]

[0108] Example H2

[0109] The composition and measurement parameters of the liquid crystal composition in Example H2 are shown in Table 11.

[0110] Table 11

[0111]

[0112]

[0113] Examples of dye liquid crystal compositions

[0114] Mixed dye liquid crystal compositions GH1-GH7 were prepared by mixing dye compositions G1-G7 with parent liquid crystal composition H1. Their performance was tested by filling them into horizontally inverted parallel liquid crystal cells with a cell thickness of 9 μm. In particular, GH6 was doped with a certain proportion of chiral agent to improve contrast, and GH7 was tested by orthogonally superimposing two liquid crystal cells to improve contrast. The composition and performance parameters of dye liquid crystal compositions GH1-GH7 are shown in Tables 12-18.

[0115] Table 12

[0116]

[0117] Table 13

[0118]

[0119]

[0120] Table 14

[0121]

[0122] Table 15

[0123]

[0124] Table 16

[0125]

[0126] Table 17

[0127]

[0128]

[0129] Table 18

[0130]

[0131] Test units GH1 to GH7 were subjected to light / heat treatment. The photothermal stability of the samples was measured by the color difference ΔE before and after the light / heat treatment. The color difference was defined according to the CIELAB standard. The light / heat treatment conditions and test results are shown in Table 19.

[0132] Table 19

[0133]

[0134] As can be seen from Examples GH1 to GH7 of the dye liquid crystal composition, following the guidance of this invention, a gray dye liquid crystal composition with chromaticity values ​​|a|≤2 and |b|≤3 can be obtained using the dye liquid crystal composition described in this invention; as can be seen from Example GH6, the introduction of a chiral agent can effectively reduce dark-state transmittance to obtain higher contrast; as can be seen from the dual-cell orthogonal superposition mode of Example GH7, extremely high contrast can be obtained in this mode; as can be seen from the photothermal stability test results of Examples GH1 to GH7, the dye liquid crystal composition formulated according to the guidance of this invention has good photothermal stability.

[0135] While this invention does not exhaustively cover all claimed dyes and dye liquid crystal compositions, those skilled in the art will foresee that, based on the disclosed embodiments described above, other similar materials can be obtained through similar methods without requiring inventive effort, simply by combining their own professional expertise. Due to space limitations, only representative embodiments are listed here.

[0136] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A gray dye composition characterized in that, The dye composition consists of dichroic dyes of components I to III. Component I is selected from dichroic dyes represented by formulas I1 to I7, which are as follows: Wherein, R1, R1', R2 and R2' are each independently H, an alkyl group having 1 to 10 carbon atoms, and an alkoxy group having 1 to 10 carbon atoms, wherein the alkyl group and alkoxy group are straight-chain or branched alkyl and alkoxy groups; Component II is selected from dichroic dyes represented by formulas II1 to II20, which are as follows: Wherein, R3, R4 and R4' are each independently H, an alkyl group having 1 to 10 carbon atoms, and an alkoxy group having 1 to 10 carbon atoms, wherein the alkyl group and alkoxy group are straight-chain or branched alkyl and alkoxy groups; Component III is selected from dichroic dyes represented by formulas III1 to III20, as follows: Wherein, R5, R5', R6 and R6' are each independently H, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms, wherein the alkyl group and alkoxy group are straight-chain or branched alkyl and alkoxy groups.

2. A grey dye composition according to claim 1, characterised in that, The mass fraction of component I is 15-60%, the mass fraction of component II is 0-65%, and the mass fraction of component III is 0-45%.

3. A grey dye liquid crystal composition characterized in that, The gray dye liquid crystal composition comprises the gray dye composition and the liquid crystal composition according to claim 1, wherein the gray dye composition accounts for 0.5% to 10% of the mass fraction of the gray dye liquid crystal composition.

4. The grey dye liquid crystal composition according to claim 3, characterized in that, The liquid crystal composition is partially composed of liquid crystal compounds of formulas A1 to A7, which are as follows: R7 and R8 are each independently selected from alkyl groups having 1 to 7 carbon atoms, alkoxy groups having 1 to 7 carbon atoms, alkenyl groups having 2 to 7 carbon atoms, enalkoxy groups having 2 to 7 carbon atoms, alkyl halogenates having 1 to 7 carbon atoms, alkoxy halogenates having 1 to 7 carbon atoms, alkenyl halogenates having 2 to 7 carbon atoms, enalkoxy halogenates having 2 to 7 carbon atoms, cyclopentyl groups, or cyclopentyl groups substituted with alkyl groups having 1 to 7 carbon atoms, alkoxy groups having 1 to 7 carbon atoms, alkenyl groups having 2 to 7 carbon atoms, or enalkoxy groups having 2 to 7 carbon atoms; wherein the alkyl group, the alkoxy group, the alkenyl group, and the enalkoxy group are straight-chain or branched alkyl groups, alkoxy groups, alkenyl groups, and enalkoxy groups.

5. The liquid crystal composition according to claim 4, wherein The liquid crystal composition comprises 10-30% by mass of a liquid crystal compound having formula A1, 1-20% by mass of a liquid crystal compound having formula A2, 20-40% by mass of a liquid crystal compound having formula A3, 5-25% by mass of a liquid crystal compound having formula A4, 5-25% by mass of a liquid crystal compound having formula A5, 10-30% by mass of a liquid crystal compound having formula A6, and 10-30% by mass of a liquid crystal compound having formula A7, wherein the mass fraction is the mass fraction of the liquid crystal compounds of formulas A1 to A7 relative to the liquid crystal composition portion.

6. The gray dye liquid crystal composition according to claim 3, wherein The gray dye liquid crystal composition further comprises a chiral agent with a mass fraction of 0-20% and a stabilizer with a mass fraction of 0-20%.

7. A grey dye liquid crystal composition according to claim 6, wherein, The chiral agent is selected from one or more of the following chiral agents:

8. A grey dye liquid crystal composition as claimed in claim 6, wherein, The stabilizer is selected from one or more of the following stabilizers: Wherein, Y5 is selected from H, F, alkyl groups having 1 to 7 carbon atoms, alkoxy groups having 1 to 7 carbon atoms, alkenyl groups having 2 to 7 carbon atoms, enalkoxy groups having 2 to 7 carbon atoms, alkyl halogenates having 1 to 7 carbon atoms, alkoxy halogenates having 1 to 7 carbon atoms, alkenyl halogenates having 2 to 7 carbon atoms, enalkoxy halogenates having 2 to 7 carbon atoms, cyclopentyl groups, or cyclopentyl groups substituted with alkyl groups having 1 to 7 carbon atoms, alkoxy groups having 1 to 7 carbon atoms, alkenyl groups having 2 to 7 carbon atoms, or enalkoxy groups having 2 to 7 carbon atoms; wherein the alkyl group, the alkoxy group, the alkenyl group, and the enalkoxy group are straight-chain or branched alkyl groups, alkoxy groups, alkenyl groups, and enalkoxy groups.

9. The use of the gray dye composition according to any one of claims 1 to 2 in light valves, switchable windows, switchable mirrors, and guest-host type displays.

10. The use of the gray dye liquid crystal composition according to any one of claims 3 to 8 in light valves, switchable windows, switchable mirrors, and guest-host type displays.

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