A high-definition bright spot LCP material and preparation method thereof

Abstract

The present application relates to a high-definition bright spot LCP material and a preparation method thereof, belonging to the technical field of polymer materials; the method comprises: obtaining a first fluorine-containing monomer and a second fluorine-containing monomer, wherein the first fluorine-containing monomer contains an acid group structure and the second fluorine-containing monomer contains a phenol structure; mixing the first fluorine-containing monomer and the second fluorine-containing monomer in a solvent to obtain a mixture; mixing the mixture with a catalyst, and then reacting to obtain an LCP material; by selecting a substance with fluorine introduced into the acid group monomer and a substance with fluorine introduced into the phenol monomer as a fluorine-containing monomer for the reaction, in the preparation process of the liquid crystal polymer, the electronic effect generated by the C-F bond can significantly change the properties of the molecule, and the influence of the acid group and the phenol structure on the clearing point of the liquid crystal material during the preparation process is combined to achieve the improvement of the clearing point of the liquid crystal material.

Description

Technical Field

[0001] The present application relates to the technical field of polymer materials, and in particular to a high-definition bright spot LCP material and a preparation method thereof. Background Art

[0002] Liquid crystal molecules usually contain a main ring structure, an alkyl chain, a polar group, a lateral group, a connecting group, etc. The structure of the liquid crystal molecule determines the physical and optical properties of the material. Liquid crystals can also be distinguished from the perspectives of viscosity, refractive index, clearing point, elastic constant, etc.

[0003] During the heating process, organic compounds initially form turbid liquids with fluidity similar to that of water, but with optical birefringence. The temperature at this point is called the melting point. When the temperature continues to rise, when the compound suddenly turns into an isotropic transparent liquid at a higher temperature, the corresponding transition temperature is called the clearing point, which is usually represented by Td or Ti.

[0004] If the clearing point is slightly higher, the liquid crystal phase will be wider and the liquid crystal state of the liquid crystal polymer will be more stable. Therefore, liquid crystal polymers with high clearing points receive more attention and research.

[0005] At present, the introduction of polar groups into liquid crystal polymers, especially fluorine-substituted compound monomers, is a commonly used method of modifying monomers to improve the clearing point of liquid crystal polymers. Studies have shown that compared with liquid crystal materials without fluorine compounds, liquid crystal materials with fluorine-containing derivatives have a wider liquid crystal phase range, and the clearing point is increased by nearly a few degrees Celsius to 100 degrees Celsius. There are also reports on the preparation of a liquid crystal material with a side chain fluorine-containing derivative, the side chain is -(CH2)2(CF2)3CF3, and the clearing point of this liquid crystal polymer material reaches above 200 degrees Celsius. However, at present, the clearing point of most liquid crystal materials is concentrated at around 150 degrees Celsius, and after specific modification, the clearing point can generally reach around 200 degrees Celsius. Summary of the invention

[0006] The present application provides a high-definition bright spot LCP material and a preparation method thereof to improve the clearing point of the LCP material.

[0007] The applicant discovered during the invention process that the reason why the clearing point of the liquid crystal material containing fluorine compounds is improved is that during the preparation of the liquid crystal, when the CH bond changes to a CF bond, the spatial effect is almost unaffected, but the electronic effect generated by the CF bond can significantly change the properties of the molecule. At present, the preparation of fluorine-containing liquid crystal materials by introducing fluorine elements mainly focuses on the position of the introduced fluorine element, the number of fluorine atoms, and the length of the carbon chain where the fluorine element is located. These are mainly attributed to the strong polarity of the CF bond and the influence of the arrangement of F atoms on the structural symmetry and regularity of the liquid crystal material. However, in the actual preparation process of fluorine-containing liquid crystal polymers, other structures and polar groups in the monomers other than F also have an impact on the clearing point of the liquid crystal material. At the same time, the synthesis process of preparing liquid crystals with different monomers is also very important for the performance of liquid crystal materials. The structures and properties of liquid crystal materials prepared under different formulas and different reaction conditions vary greatly.

[0008] In a first aspect, the present application provides a method for preparing a high-definition bright spot LCP material, the method comprising:

[0009] Obtaining a first fluorine-containing monomer and a second fluorine-containing monomer, wherein the first fluorine-containing monomer contains an acid group structure, and the second fluorine-containing monomer contains a phenol structure;

[0010] Mixing the first fluorine-containing monomer and the second fluorine-containing monomer in a solvent to obtain a mixture;

[0011] The mixture is mixed with a catalyst and then reacted to obtain an LCP material.

[0012] As an optional implementation, the second fluorine-containing monomer further contains chlorine and / or cyano structures.

[0013] As an optional embodiment, the first fluorine-containing monomer includes at least one of 2-fluoro-4-hydroxybenzoic acid, 3-fluoro-4-hydroxybenzoic acid, 2,6-difluoro-4-hydroxybenzoic acid and 2-fluoro-4-methoxybenzoic acid.

[0014] As an optional embodiment, the second fluorine-containing monomer includes at least one of 3,4,5-trifluorophenol, 4-ethoxy-2,3-difluorophenol, 2,5-difluorophenol, 3-fluoro-4-cyanophenol and 2-chloro-4-fluorophenol.

[0015] As an optional embodiment, the solvent includes at least one of N,N-dimethylacetamide solvent, N,N-dimethylformamide solvent and dichloromethane.

[0016] As an optional embodiment, the molar ratio of the first fluorine-containing monomer to the second fluorine-containing monomer is 1:(1-3); and / or

[0017] The combined mass of the first fluorine-containing monomer and the second fluorine-containing monomer mixed in every 100 mL of the solvent is 1-5 g.

[0018] As an optional embodiment, the catalyst includes one of concentrated sulfuric acid, N,N-dimethyl-4-pyridinamine, 1,3-dicyclohexylcarbodiimide or a composite of N,N-dimethyl-4-pyridinamine and 1,3-dicyclohexylcarbodiimide;

[0019] In the composite of N,N-dimethyl-4-pyridinamine and 1,3-dicyclohexylcarbodiimide, the mass ratio of N,N-dimethyl-4-pyridinamine to 1,3-dicyclohexylcarbodiimide is 1:(1-5).

[0020] As an optional embodiment, the reaction process is accompanied by stirring, and the stirring rate is 400-1500 rpm / min.

[0021] As an optional embodiment, the reaction temperature is 25-45°C; and / or

[0022] The reaction time is 16-24°C.

[0023] In a second aspect, the present application provides a high-definition bright spot LCP material, wherein the LCP material is prepared by the preparation method of the high-definition bright spot LCP material described in the first aspect.

[0024] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0025] The method provided in the embodiment of the present application selects substances that introduce fluorine into acid group monomers and phenol monomers as fluorine-containing monomers for the reaction. During the preparation process of liquid crystal polymers, the electronic effect generated by the CF bond can significantly change the properties of the molecule. Combined with the influence of the acid group and the phenol structure on the clearing point of the liquid crystal material during the preparation process, the clearing point of the liquid crystal material is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0028] Figure 1A flowchart of a method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0030] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0031] like Figure 1 As shown, the embodiment of the present application provides a method for preparing a high-definition bright spot LCP material, the method comprising:

[0032] S1. obtaining a first fluorine-containing monomer and a second fluorine-containing monomer, wherein the first fluorine-containing monomer contains an acid group structure, and the second fluorine-containing monomer contains a phenol structure;

[0033] By adopting the above design, by selecting substances that introduce fluorine on acid group monomers and fluorine on phenol monomers as fluorine-containing monomers for the reaction, in the preparation process of liquid crystal polymers, the electronic effect generated by the CF bond can significantly change the properties of the molecule, and the influence of the acid group and phenol structure on the clearing point of the liquid crystal material during the preparation process is combined to achieve an improvement in the clearing point of the liquid crystal material.

[0034] In some embodiments, the first fluorine-containing monomer includes at least one of 2-fluoro-4-hydroxybenzoic acid, 3-fluoro-4-hydroxybenzoic acid, 2,6-difluoro-4-hydroxybenzoic acid, and 2-fluoro-4-methoxybenzoic acid.

[0035] In some embodiments, the second fluorine-containing monomer also contains chlorine and / or cyano structures. Based on the fluorine-containing phenol monomer, chlorine with strong polarity and cyano with conjugated effect are selected for reaction, and the combined action of chlorine and / or cyano further improves the clearing point of the liquid crystal material. Furthermore, the second fluorine-containing monomer includes at least one of 3,4,5-trifluorophenol, 4-ethoxy-2,3-difluorophenol, 2,5-difluorophenol, 3-fluoro-4-cyanophenol and 2-chloro-4-fluorophenol.

[0036] S2. The first fluorinated monomer and the second fluorinated monomer are mixed in a solvent to obtain a mixture;

[0037] In some embodiments, the solvent includes at least one of N,N-dimethylacetamide solvent, N,N-dimethylformamide solvent and dichloromethane. The mass of the first fluorinated monomer and the second fluorinated monomer mixed in each 100 mL of the solvent is 1-5 g. The molar ratio of the first fluorinated monomer to the second fluorinated monomer is 1:(1-3).

[0038] S3. The mixture and the catalyst are mixed and reacted to obtain an LCP material.

[0039] In some embodiments, the catalyst includes concentrated sulfuric acid, N,N-dimethyl-4-pyridinamine, 1,3-dicyclohexylcarbodiimide or a mixture of N,N-dimethyl-4-pyridinamine and 1,3-dicyclohexylcarbodiimide; in the mixture of N,N-dimethyl-4-pyridinamine and 1,3-dicyclohexylcarbodiimide, the mass ratio of N,N-dimethyl-4-pyridinamine to 1,3-dicyclohexylcarbodiimide is 1:(1-5).

[0040] In some embodiments, the reaction is accompanied by stirring at a rate of 400-1500 rpm / min. The reaction temperature is 25-45°C; and the reaction time is 16-24°C.

[0041] The selection of fluorine-containing monomers, monomer ratio and concentration, catalyst selection and addition amount, reaction temperature and time, stirring rate and other parameters are used to synergistically improve the clearing point of the liquid crystal material, so that the clearing point can reach 225°C or even 268°C.

[0042] Based on a general inventive concept, an embodiment of the present application further provides a high-definition bright spot LCP material, wherein the LCP material is prepared by the method for preparing the high-definition bright spot LCP material provided above.

[0043] The LCP material is prepared based on the above method. The specific steps of the method can refer to the above embodiment. Since the LCP material adopts part or all of the technical solutions of the above embodiment, it at least has all the beneficial effects brought by the technical solutions of the above embodiment, which will not be repeated here.

[0044] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0045] Example 1

[0046] A method for preparing a high-definition bright spot LCP material, the method comprising:

[0047] Under nitrogen, 5mmol (0.78g) of 2-fluoro-4-hydroxybenzoic acid, 7.5mmol (0.975g) of 2,5-difluorophenol and 100ml of N,N-dimethylacetamide were added to a three-necked flask and stirred to mix evenly. The molar ratio of 2-fluoro-4-hydroxybenzoic acid and 2,5-difluorophenol was 1:1.5, and the ratio of monomer to solvent was 1.755g / 100ml. Then 0.176g of concentrated sulfuric acid was added to the uniformly mixed 2-fluoro-4-hydroxybenzoic acid + 2,5-difluorophenol N,N-dimethylacetamide solution system, and the amount of concentrated sulfuric acid added accounted for 10% of the mass of the reaction monomer. The reaction was carried out at room temperature with a stirring speed of 600rpm / min for 16h. After the reaction was completed, the reaction system was filtered, and the filtered product was first washed with pure water and then with ethanol, and then placed in a vacuum drying oven to dry to obtain a liquid crystal material.

[0048] Example 2

[0049] A method for preparing a high-definition bright spot LCP material, the method comprising:

[0050] Under nitrogen, 5mmol (0.78g) of 2-fluoro-4-hydroxybenzoic acid, 10mmol (1.3g) of 2,5-difluorophenol and 100ml of N,N-dimethylacetamide were added to a three-necked flask and stirred to mix evenly. The molar ratio of 2-fluoro-4-hydroxybenzoic acid and 2,5-difluorophenol was 1:2, and the ratio of monomer to solvent was 2.08g / 100ml. Then 0.250g of concentrated sulfuric acid was added to the uniformly mixed 2-fluoro-4-hydroxybenzoic acid + 2,5-difluorophenol N,N-dimethylacetamide solution system, and the amount of concentrated sulfuric acid added accounted for 12% of the mass of the reaction monomer. The reaction was carried out at room temperature with a stirring speed of 800rpm / min for 16h. After the reaction was completed, the reaction system was filtered, and the filtered product was first washed with pure water and then with ethanol, and then placed in a vacuum drying oven to dry to obtain a liquid crystal material.

[0051] Example 3

[0052] A method for preparing a high-definition bright spot LCP material, the method comprising:

[0053] Under nitrogen, 6mmol (1.044g) of 2,6-difluoro-4-hydroxybenzoic acid, 12mmol (2.088g) of 4-ethoxy-2,3-difluorophenol and 100ml of N,N-dimethylformamide were added to a three-necked flask and stirred to mix evenly. The molar ratio of 2,6-difluoro-4-hydroxybenzoic acid and 4-ethoxy-2,3-difluorophenol was 1:2, and the ratio of monomer to solvent was 3.132g / 100ml. Then 0.313g of concentrated sulfuric acid was added to the uniformly mixed 2,6-difluoro-4-hydroxybenzoic acid + 4-ethoxy-2,3-difluorophenol N,N-dimethylformamide solution system, and the amount of concentrated sulfuric acid added accounted for 10% of the mass of the reaction monomer. The reaction was carried out at room temperature with a stirring speed of 1000rpm / min for 20h. After the reaction is completed, the reaction system is filtered, and the filtered product is first washed with pure water and then with ethanol, and then placed in a vacuum drying oven for drying to obtain a liquid crystal material.

[0054] Example 4

[0055] A method for preparing a high-definition bright spot LCP material, the method comprising:

[0056] Under nitrogen, 6mmol (1.044g) of 2,6-difluoro-4-hydroxybenzoic acid, 12mmol (2.088g) of 4-ethoxy-2,3-difluorophenol and 100ml of N,N-dimethylformamide were added to a three-necked flask and stirred to mix evenly. The molar ratio of 2,6-difluoro-4-hydroxybenzoic acid and 4-ethoxy-2,3-difluorophenol was 1:2, and the ratio of monomer to solvent was 3.132g / 100ml. Then 0.313g of N,N-dimethyl-4-pyridinamine was added to the N,N-dimethylformamide solution system of 2,6-difluoro-4-hydroxybenzoic acid + 4-ethoxy-2,3-difluorophenol, and the amount of N,N-dimethyl-4-pyridinamine added accounted for 10% of the mass of the reaction monomer. The reaction was carried out at 40°C in a water bath at a stirring speed of 1000rpm / min for 20h. After the reaction is completed, the reaction system is filtered, and the filtered product is first washed with pure water and then with ethanol, and then placed in a vacuum drying oven for drying to obtain a liquid crystal material.

[0057] Example 5

[0058] A method for preparing a high-definition bright spot LCP material, the method comprising:

[0059] Under nitrogen, 6mmol (1.044g) of 2,6-difluoro-4-hydroxybenzoic acid, 12mmol (1.644g) of 3-fluoro-4-cyanophenol and 100ml of N,N-dimethylformamide were added to a three-necked flask and stirred to mix evenly. The molar ratio of 2,6-difluoro-4-hydroxybenzoic acid to 3-fluoro-4-cyanophenol was 1:2, and the ratio of monomer to solvent was 2.688g / 100ml. Then 0.081g of N,N-dimethyl-4-pyridinamine and 0.242g of 1,3-dicyclohexylcarbodiimide were added to the evenly mixed 2,6-difluoro-4-hydroxybenzoic acid + 3-fluoro-4-cyanophenol N,N-dimethylformamide solution system, and the amount of the composite catalyst added accounted for 12% of the mass of the reaction monomers. The reaction was carried out for 20 hours at a stirring speed of 1000 rpm / min under the condition of 40° C. in a water bath. After the reaction was completed, the reaction system was filtered, and the filtered product was first washed with pure water and then with ethanol, and then placed in a vacuum drying oven to obtain a liquid crystal material.

[0060] Comparative Example 1

[0061] The LCP material was purchased from the market.

[0062] The LCP materials provided in Examples 1-5 and Comparative Example 1 were tested for clearing points, and the test results are shown in the following table:

[0063] Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Clearing point / ℃ 178 185 196 225 268 About 150

[0064] From the above table, it can be seen that by using the method provided in the application embodiment, when synthesizing liquid crystal materials by selecting two monomers containing fluorine, optimizing the monomer type and ratio, reaction monomer concentration, catalyst type and addition amount, and process conditions, the clearing point of the liquid crystal material can reach at least 178°C, and can even reach 225°C under specific parameter selection. When synthesizing liquid crystal materials by selecting monomers containing fluorine and cyano groups, optimizing the catalyst type and addition amount and reaction temperature, the clearing point of the liquid crystal material can reach 268°C.

[0065] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0066] In this application, unless otherwise specified, directional words such as "upper" and "lower" used refer specifically to the directions of the drawings in the accompanying drawings. In addition, in the description of the specification of this application, the terms "include", "comprise", etc. mean "including but not limited to".

[0067] In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. Wherein A, B can be singular or plural. In this article, "at least one" refers to one or more, and "multiple" refers to two or more. "At least one", "the following at least one (individual)" or similar expressions refer to any combination of these items, including any combination of single (individual) or plural (individual). For example, "at least one (individual) of a, b, or c", or "at least one (individual) of a, b, and c", can all represent: a, b, c, ab (i.e. a and b), ac, bc, or abc, wherein a, b, c can be single or multiple respectively.

[0068] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for preparing a high-definition bright spot liquid crystal material, It is characterized in that The method comprises: Obtaining a first fluorine-containing monomer and a second fluorine-containing monomer, wherein the first fluorine-containing monomer contains an acid group structure, and the second fluorine-containing monomer contains a phenol structure; Mixing the first fluorine-containing monomer and the second fluorine-containing monomer in a solvent to obtain a mixture; The mixture and a catalyst are mixed and reacted to obtain a liquid crystal material; The first fluorine-containing monomer includes at least one of 2-fluoro-4-hydroxybenzoic acid, 3-fluoro-4-hydroxybenzoic acid, 2,6-difluoro-4-hydroxybenzoic acid and 2-fluoro-4-methoxybenzoic acid; The second fluorine-containing monomer includes at least one of 3,4,5-trifluorophenol, 4-ethoxy-2,3-difluorophenol, 2,5-difluorophenol, 3-fluoro-4-cyanophenol and 2-chloro-4-fluorophenol; The molar ratio of the first fluorine-containing monomer to the second fluorine-containing monomer is 1:(1-3); The total mass of the first fluorinated monomer and the second fluorinated monomer mixed in every 100 mL of the solvent is 1-5 g; The catalyst comprises one of concentrated sulfuric acid, N,N-dimethyl-4-pyridinamine, 1,3-dicyclohexylcarbodiimide or a composite of N,N-dimethyl-4-pyridinamine and 1,3-dicyclohexylcarbodiimide; In the composite of N,N-dimethyl-4-pyridinamine and 1,3-dicyclohexylcarbodiimide, the mass ratio of N,N-dimethyl-4-pyridinamine to 1,3-dicyclohexylcarbodiimide is 1:(1-5); The reaction temperature is 25-45°C; The reaction time is 16-24h.

2. The method for preparing the high-definition bright spot liquid crystal material according to claim 1, It is characterized in that The solvent includes at least one of N,N-dimethylacetamide solvent, N,N-dimethylformamide solvent and dichloromethane.

3. The method for preparing the high-definition bright spot liquid crystal material according to claim 1, It is characterized in that The reaction process is accompanied by stirring at a rate of 400-1500 rpm.

4. A high-definition bright spot liquid crystal material, It is characterized in that The liquid crystal material is prepared by the method for preparing a high-definition bright spot liquid crystal material according to any one of claims 1 to 3.

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