CN110669529A - Color liquid crystal material and application thereof - Google Patents

Abstract

The invention discloses a color liquid crystal material and its application; synthesizes an acrylate additive containing isosorbide and other groups, and synthesizes an acrylate liquid crystal molecule containing p-hydroxytoluene; By mixing liquid crystal molecules, bright, bright and colorful liquid crystal materials can be obtained. The invention has the advantages of simple process route, low consumption of raw materials, short reaction time and convenient operation.

Description

Color liquid crystal material and its application

technical field

The invention belongs to the field of liquid crystal, and particularly relates to a preparation method of a liquid crystal material containing an additive.

Background technique

Liquid crystal is a special form of matter, which has both the fluidity of liquid and the anisotropy of some crystal molecules. Liquid crystal luminescent materials have great application potential in the fields of displays and sensors, but the most common problem encountered when using liquid crystal materials is how to adjust the diversity and brightness of their reflected colors. The prior art discloses some methods for modifying liquid crystals, but there are defects such as poor compatibility and low HTP value; therefore, a system that can provide both compatibility and high HTP value is urgently needed, thereby obtaining a high-performance system color liquid crystal material.

SUMMARY OF THE INVENTION

The invention synthesizes an acrylate additive containing isosorbide and other groups, and synthesizes an acrylate liquid crystal molecule containing p-hydroxytoluene; by mixing the acrylate additive with the liquid crystal molecules, bright and bright, Color-rich liquid crystal material. The invention has the advantages of simple process route, low consumption of raw materials, short reaction time and convenient operation.

The technical scheme of the present invention is as follows:

A color liquid crystal material includes acrylate additives and liquid crystal molecules.

The invention also discloses the preparation method of the above-mentioned color liquid crystal material, which comprises the following steps: heating and mixing the acrylate additive and liquid crystal molecules to obtain the color liquid crystal material.

The color liquid crystal material of the present invention is prepared from acrylate additives and liquid crystal molecules, wherein the mass of the acrylate additives is 5.0-7.5% of the mass of the liquid crystal molecules.

In the present invention, the chemical structural formula of acrylate additive is as follows:

The chemical structural formula of liquid crystal molecules is as follows:

Wherein, A ₁ and A ₂ are independently selected from hydrogen or methyl; n and m are independently selected from 4-9; B ₁ and B ₂ independently represent C6-C18 aromatic groups, that is, contain 6-18 carbon atoms aromatic groups, such as:

M is the following group:

N is the following group:

In the present invention, heating and mixing consists of 1 to 10 times of heating and stirring, and increasing the number of heating and stirring can make the liquid crystal and additives in the system more uniformly mixed, and the color is more uniform. The temperature of each heating and stirring is 80~150°C, and the time is 4~15 minutes.

In the present invention, the method for synthesizing acrylate additives includes the following steps: under nitrogen protection, acrylate benzoic acid, p-hydroxybenzoate, dicyclohexylcarbodiimide and 4-dimethylaminopyridine are reacted in a solvent , to obtain acrylate additives. Preferably, after the reaction is completed, the reaction solution is filtered, and the collected filtrate is subjected to vacuum distillation and spin-dried, and then recrystallized with methanol to obtain a white solid, which is an acrylate additive.

In the present invention, the method for synthesizing liquid crystal molecules includes the following steps: under nitrogen protection, acrylate benzoic acid, hydroxybenzene, dicyclohexylcarbodiimide and 4-dimethylaminopyridine are reacted in a solvent to obtain liquid crystal molecules. Preferably, after the reaction is completed, the reaction solution is filtered, the collected filtrate is distilled under reduced pressure and then recrystallized with methanol to obtain a white solid, which is a liquid crystal molecule.

In the above preparation method, the solvent is tetrahydrofuran; the reaction time is 1 to 3 days; the acrylate benzoic acid is acrylate hexacarbonic acid; Binaphthalene diphenol ester or 4,4'-dihydroxyazophenyl p-hydroxybenzoate; hydroxybenzene is 2,5-dihydroxytoluene or 4,4'-dihydroxyazophenyl p-hydroxybenzoate.

The preparation method disclosed in the present invention can be exemplified as follows:

(1) Synthesis of acrylate additives:

Weigh acrylate benzoic acid (7.95~12.71g), isosorbide p-hydroxybenzoate (5~8g), dicyclohexylcarbodiimide (DCC) (3.47~5.55g), 4-dimethylaminopyridine (DMAP) (0.316~0.506g) in a 100mL three-necked flask for use. Measure 50~150mL of freshly distilled tetrahydrofuran (THF) into the flask, and react under nitrogen protection for 1~3 days. After the reaction is completed, the reaction solution is filtered, the collected filtrate is distilled under reduced pressure and spin-dried, and then recrystallized with methanol to obtain a white solid, which is an acrylate additive.

(2) Synthesis of liquid crystal molecules:

Acrylate benzoic acid (4~9g), 2,5-dihydroxytoluene (0.85~1.91g), DCC (3.10~6.98g), DMAP (0.167~0.376g) were weighed in a 100mL three-necked flask for use. Measure 50~150mL of freshly distilled THF into the flask, and react under nitrogen protection for 1~3 days. After the reaction is completed, the reaction solution is filtered, the filtrate is collected, distilled under reduced pressure and spin-dried, and then recrystallized with methanol to obtain a white solid, which is a liquid crystal molecule.

(3) Preparation of liquid crystal materials:

Weigh acrylate additives (40~120mg, 0.053mmol), add liquid crystal molecules (1g, 1.1mmol) into the sample bottle, heat at 80~150℃ until the mixture is clear and keep for 4~15 minutes, for one heating and stirring, use Stir the sample with a vortex shaker, and repeat the heating and stirring steps 4 to 10 times to mix the sample evenly, and the target liquid crystal material is obtained.

A small amount of liquid crystal material sample was dipped and smeared on the cover glass, and then covered with a layer of cover glass to form a sandwich structure. After the natural cooling, bright and bright colors can be observed.

The advantages of the present invention:

1. The present invention prepares additives containing groups such as isosorbide. Isosorbide can provide high HTP value and can achieve greater distortion effect with less addition.

2. The additive of the present invention and the liquid crystal molecules have similar long carbon chains, have better compatibility, and solve the problem of crystallization of liquid crystal mixtures in the prior art.

3. Both the additive and the liquid crystal molecules of the present invention are capped with acrylate, which can easily undergo a cross-linking reaction to form a colored polymer film, which has wide application prospects in optically active optical films.

Description of drawings

Fig. 1 is the color photograph of each formula liquid crystal material 1 of embodiment one a～f;

Fig. 2 is the DSC curve of each formula liquid crystal material 1 of Example 1 a-b;

Fig. 3 is the DSC curve of each formula liquid crystal material 1 of Example 1 c ~ d;

Fig. 4 is the DSC curve of each formula liquid crystal material 1 of Example 1 e~f;

5 is a polarizing microscope photograph of each formulation of liquid crystal material 1 in Example 1 a-f;

Fig. 6 is the nuclear magnetic image of liquid crystal molecules of Example 1;

FIG. 7 is a color photograph of each formulation of liquid crystal material 2 in Example 2. FIG.

Detailed ways

The present invention will be further elaborated below in conjunction with the examples.

The preparation method of the color liquid crystal material of the present invention is as follows: the acrylic acid ester additive and the liquid crystal molecules are heated and mixed to obtain the color liquid crystal material.

Example 1

A liquid crystal material 1 comprising the following structure was prepared:

Acrylate Additive A

Liquid crystal molecule A

(1) Synthesis of Acrylate Additive A:

Weigh acrylate hexacarbonate (7,945g, 27.2mmol), isosorbide p-hydroxybenzoate (5g, 12.9mmol), DCC (3.468g, 16.8mmol), DMAP (0.316g, 2.59mmol) in 100mL Three-necked flask for use. Measure 70 mL of freshly distilled THF into the flask, and react for two days under nitrogen protection. After the reaction, the reaction solution was filtered, and the collected filtrate was distilled under reduced pressure and spin-dried, and then recrystallized with methanol to obtain a white solid as acrylate additive A with a yield of 91%.

(2) Synthesis of liquid crystal molecule A:

Weigh acrylate hexacarbonate (4g, 13.68mmol), 2,5-dihydroxytoluene (0.85g, 6.84mmol), DCC (3.103g, 15.05mmol), DMAP (0.167g, 1.368mmol) in 100mL three wells Flask ready to use. Measure 70 mL of freshly distilled THF into the flask, and react for two days under nitrogen protection. After the reaction, the reaction solution was filtered, the filtrate was collected, distilled under reduced pressure and spin-dried, and then recrystallized with methanol to obtain a white solid as liquid crystal molecule A with a yield of 72%.

(3) Preparation of liquid crystal material 1:

Weigh the acrylate additive A (50 mg, 0.053 mmol), add the liquid crystal molecule A (1 g, 1.1 mmol) to the sample bottle, heat it in an oil bath at 130 °C until the mixture is clear, and then stir the sample with a vortex shaker and keep it for 5 minutes. One heating and stirring, repeat the heating and stirring step 5 times; then dip a small amount of sample and apply it on the cover glass, and then cover it with a layer of cover glass to form a sandwich structure. After it cools down naturally, a bright and bright orange can be observed, as shown in Figure 1 -a shown.

The acrylate additive A and the liquid crystal A in different mass ratios are mixed by the above method to obtain liquid crystal materials of different colors. The formula is shown in Table 1. The color of the liquid crystal material is shown in a~f in Figure 1. The color of the color liquid crystal material is uniform. It can be seen that the liquid crystal and the additive have good compatibility, and there is no phase separation phenomenon. Combining the DSC curve data, ellipsometer data and reflection circular dichroism data of each formula liquid crystal material 1 in Figs. 2, 3 and 4, the physical property table of liquid crystal material 1 of various colors can be obtained. FIG. 5 is a polarizing microscope photograph of each formulation of liquid crystal material 1 in Example 1 a to f; FIG. 6 is an NMR image of the liquid crystal molecule in Example 1.

Table 1 and DSC test can illustrate the liquid crystallinity; when the acrylate additive A is 35 mg and the liquid crystal molecule A is 1 g, the material prepared by the same method has no color; when the acrylate additive A is 100 mg and the liquid crystal molecule A is 1 g , the material prepared by the same method has no color; the above 2,5-dihydroxytoluene is replaced with an equimolar amount of 5-fluororesorcinol (CAS No. 75996-29-1), and the rest remains unchanged to obtain liquid crystal molecules, Take 1 g and 60 mg of acrylate additive A by heating and mixing by the same method as above, and the obtained liquid crystal material also produces nearly green color, but the HTP value is 45.6, which is on the low side.

Example 2 Preparation of liquid crystal material 2 comprising the following components:

Acrylate Additive B

Liquid crystal molecule A

(1) Synthesis of Acrylate Additive B:

Weigh acrylate hexacarbonate (6g, 20.5mmol), binaphthyl p-hydroxybenzoate (2.25g, 9.78mmol), DCC (8.06g, 39.12mmol), DMAP (0.477g, 3.9mmol) in 100mL three-necked flask for use. Measure 60 mL of freshly distilled THF into the flask, and react for two days under nitrogen protection. After the reaction, the reaction solution was filtered, the filtrate was distilled under reduced pressure and spin-dried, and then recrystallized with methanol to obtain the product.

(2) Synthesis of liquid crystal molecule A:

Synthesized with the same procedure as Example 1.

(3) Preparation of liquid crystal material 2:

Weigh a certain proportion of acrylate additive B, add liquid crystal molecules A into the sample bottle, heat the mixture in an oil bath at 150 °C until the mixture is clear, and use a vortex shaker to stir the sample for 5 minutes. For one heating and stirring, repeat the heating and stirring step 5 Second-rate. A small amount of sample is dipped and smeared on the cover glass, and then a layer of cover glass is covered to form a sandwich structure, and the liquid crystal material 2 can be obtained after the natural cooling. Figure 7 is a color photo of each formulation of liquid crystal material 2 in Example 2, wherein the liquid crystal molecule A is 1 g, and the mass of the acrylate additive B is 50 mg, 55 mg, 60 mg, 65 mg, 70 mg, and 75 mg, respectively corresponding to the left to the left in Figure 7. The six colors on the right.

Example 3 Preparation of liquid crystal material 3 comprising the following components:

Acrylate Additive A

Liquid crystal molecules B

(1) Synthesis of Acrylate Additive A:

Synthesized with the same procedure as Example 1.

(2) Synthesis of liquid crystal molecules B:

Weigh acrylate hexacarbonate (7g, 23.96mmol), 4,4'-dihydroxyazophenyl p-hydroxybenzoate (2.63g, 11.41mmol), DCC (9.41g, 45.64mmol), DMAP (0.557g) , 4.56mmol) in a 100mL three-necked flask for use. Measure 80 mL of freshly distilled THF into the flask, and react for two days under nitrogen protection. After the reaction, the reaction solution was filtered, the filtrate was distilled under reduced pressure and spin-dried, and then recrystallized with methanol to obtain the product.

(3) Preparation of liquid crystal material 3:

Weigh a certain proportion of acrylate additive A, add liquid crystal B into the sample bottle, heat the mixture in an oil bath at 140°C for 7 minutes, stir the sample with a vortex shaker, and repeat the heating and stirring step 5 times to make the sample mix evenly . A small amount of sample is dipped and smeared on the cover glass, and then a layer of cover glass is covered to form a sandwich structure, and the liquid crystal material 3 can be obtained after the natural cooling. The liquid crystal molecule B is 1 g, and the mass of the acrylate additive A is 50 mg, 55 mg, 60 mg, 65 mg, 70 mg, and 75 mg, corresponding to six colors respectively.

In the present invention, a certain proportion of additives are added to the liquid crystal material to obtain cholesteric liquid crystal, and the incident light is selectively reflected to emit bright and bright reflected light; the additive is a liquid crystal additive with high helical twisting force, Using its optical activity and high helical twisting force can make liquid crystal molecules reflect specific wavelengths, and adjusting its concentration can change the helical pitch of liquid crystal molecules; from increasing the helical twisting force constant (HTP value) of the additive and increasing chiral molecules and liquid crystals The performance of the chiral liquid crystal material is improved from two aspects of molecular compatibility; the present invention solves the problems of poor compatibility between liquid crystal and additives in the prior art and cannot provide high HTP value.

Claims (10)

1. A color liquid crystal material comprises an acrylate additive and liquid crystal molecules.

2. The colored liquid crystal material of claim 1, wherein the acrylate-based additive has the following chemical formula:

the chemical structural formula of the liquid crystal molecules is as follows:

。

3. the color liquid crystal material according to claim 2, wherein A is₁、A₂Independently selected from hydrogen or methyl, n, m independently selected from 4 ~ 9, B₁、B₂Independently represents a C6 ~ C18 aromatic group, M is the following group:

n is the following group:

。

4. the color liquid crystal material of claim 1, wherein the preparation method of the color liquid crystal material comprises the step of heating and mixing the acrylate additives and the liquid crystal molecules to obtain the color liquid crystal material.

5. The colored liquid crystal material of claim 4, wherein the mass of the acrylate-based additive is 5.0 ~ 7.5.5% of the mass of the liquid crystal molecules.

6. The colored liquid crystal material of claim 4, wherein the heat mixing is performed at 1 ~ 10 times of heat stirring, and the temperature of each heat stirring is 80 ~ 150 ℃ for 4 ~ 15 minutes.

7. The color liquid crystal material of claim 1, wherein the method for synthesizing the acrylate additive comprises the steps of reacting acrylic ester benzoic acid, p-hydroxybenzoate, dicyclohexylcarbodiimide and 4-dimethylaminopyridine in a solvent under the protection of nitrogen to obtain the acrylate additive; the synthesis method of the liquid crystal molecules comprises the following steps of reacting acrylic ester benzoic acid, hydroxybenzene, dicyclohexylcarbodiimide and 4-dimethylaminopyridine in a solvent under the protection of nitrogen to obtain the liquid crystal molecules.

8. The color liquid crystal material of claim 1, wherein the solvent is tetrahydrofuran, the reaction time is 1 ~ 3 days, the acrylate benzoic acid is hexa-carbon acrylate benzoic acid, the p-hydroxybenzoate ester is p-hydroxybenzoate isosorbide, p-hydroxybenzoate binaphthyl diphenol ester or p-hydroxybenzoate 4,4 '-dihydroxyazophenyl ester, and the hydroxybenzene is 2, 5-dihydroxytoluene or p-hydroxybenzoate 4, 4' -dihydroxyazophenyl ester.

9. The method for preparing a color liquid crystal material according to claim 1, comprising the step of heating and mixing the acrylate-based additive and the liquid crystal molecules to obtain the color liquid crystal material.

10. Use of the colored liquid crystal material according to claim 1 for the preparation of liquid crystal materials.

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