High refractive index precursor solution, preparation method and application thereof

Abstract

The application discloses a high-refractive-index precursor liquid, a preparation method and application thereof, and relates to the technical field of high-refractive-index precursor liquids, and specifically discloses the preparation method, which comprises the following steps: 1) preparing nano zirconium oxide; 2) mixing the obtained nano zirconium oxide and a ligand B to carry out a reaction, and obtaining an intermediate product; 3) mixing the intermediate product and a ligand C to carry out a reaction, and obtaining ligand-treated nano zirconium oxide; 4) mixing the ligand-treated nano zirconium oxide and a solvent D to carry out a reaction, and then carrying out centrifugal treatment to obtain a target product, the high-refractive-index precursor liquid; and related conditions in each step are strictly controlled. According to the preparation method, the particle size and morphology of nano zirconium oxide inorganic particles are controlled through optimization of a synthesis method, and the dispersion stability of the nano zirconium oxide inorganic particles is effectively improved through specific ligands, so that the obtained precursor liquid not only has a high refractive index, but also has good stability, the storage difficulty is reduced, and support conditions are provided for large-scale production.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of fine chemical industry, and particularly relates to a high-refractive precursor liquid, a preparation method and application thereof. BACKGROUND

[0002] Micro lens technology (MLP) is to prepare micro lenses on each sub-pixel EL of an OLED through photolithography, and to introduce high-refractive materials to make light emitted by the EL directly undergo total reflection at the interface of the lens, so as to realize focusing of the light. According to relevant research tests, the introduction of the MLP technology can reduce the overall power consumption of the OLED screen by about 10-15%.

[0003] The high-refractive material can be obtained by curing a high-refractive ultraviolet light-curable ink under irradiation of ultraviolet light. A common method for increasing the refractive index of a material is to add nano zirconium oxide inorganic particles with high refractive index to the light-curable ink system. The nano zirconium oxide inorganic particles have a wide refractive index range and can achieve the characteristics of continuous adjustable refractive index. However, the size, particle size distribution and dispersion uniformity of the nano particles in the light-curable ink are difficult points in the preparation of the high-refractive material, and have a great influence on the optical and mechanical properties of the high-refractive material.

[0004] At present, the nano zirconium oxide inorganic particles are usually prepared by a traditional ball milling method, that is, large-diameter zirconium oxide inorganic particles are ground to a desired size through physical action. However, the nano zirconium oxide inorganic particles obtained by grinding often have uneven particle size and uneven shape under electron microscopy, which leads to poor modification effect of the ligand on the particles in the later stage, thereby causing phenomena such as high haze of the high-refractive precursor liquid, easy agglomeration and sedimentation. In addition, if the modification ligand is not reasonably selected, the dispersion stability of the nano zirconium oxide inorganic particles in the resin or solvent is affected, so that batch production and storage cannot be realized. SUMMARY

[0005] The purpose of the present application is to overcome the shortcomings of the prior art, and to provide a high-refractive precursor liquid, a preparation method and application thereof. The preparation method first obtains nano zirconium oxide inorganic particles with uniform size and spherical appearance by selecting a zirconium source, a solvent A, an additive component and a reaction ratio, and then controlling relevant parameters during the reaction. The nano zirconium oxide inorganic particles are modified by a specific ligand, so that the nano zirconium oxide inorganic particles can be stably dispersed in the resin or solvent for a long time. Therefore, the prepared precursor liquid not only has a high refractive index, but also has good stability.

[0006] In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme:

[0007] On the one hand, the present application provides a preparation method of a high-refractive precursor liquid, which comprises the following steps:

[0008] Step one, the zirconium source, solvent A and additives are added to the reaction kettle according to the reaction equivalent ratio, heated and cooled to room temperature after reaction, then centrifuged, washed and calcined to obtain nano zirconium oxide;

[0009] Step two, the nano zirconium oxide obtained in step one is mixed with ligand B to obtain an intermediate product;

[0010] Step three, the intermediate product obtained in step two is mixed with ligand C to obtain ligand-treated nano zirconium oxide;

[0011] Step four, the ligand-treated nano zirconium oxide obtained in step three is mixed with solvent D to obtain the target product high refractive precursor liquid after reaction and centrifugation.

[0012] The mass ratio of the nano zirconium oxide in step one, ligand B in step two and ligand C in step three is 1:(0.1-10):(0.1-10).

[0013] Further, the specific process in step one is: first, the zirconium source, solvent A and additives are added to the reaction kettle according to the reaction equivalent ratio, mixed uniformly, heated to a temperature of 78-200℃, reacted for 10-14h and cooled to room temperature; then centrifuged to remove most of the solvent A, washed with ethanol or water, and finally calcined at a temperature of 400-500℃ for 0.5-2h to obtain nano zirconium oxide (powder).

[0014] The molar ratio of the zirconium source to the additive is 1:(1-3), and the mass ratio of the zirconium source to the solvent A is 1:(1-10).

[0015] Further, the zirconium source in step one is one or more of zirconium oxychloride octahydrate, zirconium chloride, zirconium nitrate, zirconium oxynitrate, zirconium carbonate hydroxide, zirconium trifluoroacetate, zirconium n-propylate, zirconium isopropylate, zirconium n-butylate, zirconium butanedioate and zirconium pyrophosphate.

[0016] The solvent A is any one of isopropyl alcohol, water and benzyl alcohol;

[0017] The additive is one or more of sodium hydroxide, potassium hydroxide, potassium carbonate, sodium carbonate, sodium bicarbonate, cesium carbonate, ammonia, ammonium bicarbonate, sodium tert-butoxide, potassium tert-butoxide, sodium methoxide, sodium ethoxide, diethylamine, triethylamine, pyridine and diisopropylamine.

[0018] Further, the nano zirconium oxide obtained in step one is reacted with organic carboxylic acid ligand B at a temperature of 75-175℃ for 10-14h, and then centrifuged and washed with ethanol to remove excess ligand to obtain an intermediate product.

[0019] Further, the organic carboxylic acid is one or more of formic acid, acetic acid, n-propionic acid, isobutyric acid, n-pentanoic acid, isopentanoic acid, neopentanoic acid, n-octanoic acid, n-decanoic acid, stearic acid, palmitic acid, lauric acid, myristic acid, palmitic acid, arachidic acid, oleic acid, linoleic acid, linolenic acid, arachidonic acid, succinic acid, adipic acid, methacrylic acid, pimelic acid, and suberic acid.

[0020] Preferably, from the perspective of the photo-curable reaction of the high-refractive precursor liquid participating in the (meth)acrylate system, the organic carboxylic acid can be selected to contain an unsaturated double bond, especially a carbon-carbon double bond. For example, one or more of methacrylic acid, oleic acid, linoleic acid, linolenic acid, and arachidonic acid is preferred.

[0021] Further, the specific process in Step Three is to react the intermediate product obtained in Step Two with the ligand C of the photo-curable group-containing acrylic ester compound at a temperature of 55-155°C for 4-8 hours, centrifuge after the reaction is completed, and then wash with ethanol to remove excess ligand and obtain the ligand-treated nano-zirconia.

[0022] Further, the photo-curable group-containing acrylic ester compound is one or more of methacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, allyl methacrylate, butyl methacrylate, isobutyl methacrylate, 3-(tri-allylsilyl)propyl methacrylate, 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propyl methacrylate, 1,3-bis(4-benzoyl-3-hydroxyphenoxy)propan-2-yl methacrylate, 2,3-dibromopropyl methacrylate, 3-(3,5,7,9,11,13,15-heptacyclopentylpentacyclooctasiloxanyl)propyl methacrylate, 3-(dimethylamino)propyl methacrylate, bis-3-methacryloyloxypropyltetramethyldisiloxane, 3-methacryloyloxypropyldimethylethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, 3-chloro-2-hydroxypropyl methacrylate, bis-3-methacryloyloxypropyltetramethyldisiloxane, 3-methacryloyloxypropyltriethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, 3-(methacryloyloxy)propyltris(trimethylsiloxy)silane, and 3-(methacryloyloxy)propyltrimethoxysilane.

[0023] Preferably, the ligand C is one or more of 3-(3,5,7,9,11,13,15-heptacyclopentylpentacyclooctasiloxanyl) methyl acrylate, 3-(dimethylamino) methyl acrylate, bis-3-methacryloyloxypropyltetramethyldisiloxane, 3-methacryloyloxypropyldimethylethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, methacryloyloxypropylmethyldiethoxysilane, bis-3-methacryloyloxypropyltetramethyldisiloxane, methacryloyloxypropyltriethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, methacryloyloxypropyltris(trimethylsiloxy)silane, 3-(methacryloyloxy)propyltrimethoxysilane.

[0024] Further, the solvent D in the step four is any one of acetone, 1,1-dichloroethane, tetrahydrofuran, ethyl acetate, ethanol, cyclohexane, acetonitrile, 1,2-dichloroethane, ethylene glycol dimethyl ether, 1,4-dioxane, toluene, propylene glycol methyl ether acetate, N,N-dimethylformamide, N-methylformamide, N-methylpyrrolidone, dimethyl sulfoxide, diacetone alcohol, hexamethylphosphoric acid triamide, glycerol.

[0025] The nano zirconium oxide inorganic particle prepared by the method has a particle size of 5-10 nm, and most of the nano zirconium oxide inorganic particle is in a tetragonal phase and / or a cubic phase crystal grain structure, and the mass of the tetragonal phase and the cubic phase crystal grain structure accounts for more than 80% of the nano zirconium oxide.

[0026] In another aspect, the application provides a precursor liquid prepared based on the above preparation method, and the refractive index of the precursor liquid is 1.56-1.70. By controlling the content of the nano zirconium oxide, the controllability of the high-refractive precursor liquid can be realized.

[0027] In a third aspect, the application provides an application of the high-refractive precursor liquid, and the high-refractive precursor liquid is used for preparing optical materials and is prepared based on the above preparation method.

[0028] Specifically, the high-refractive precursor liquid is used for, but not limited to, preparing high-refractive products for flat panel display, such as prism anti-reflection film, high-refractive over-coat, high-refractive ink, and the like, and is used in cooperation with low-refractive materials to construct a Micro Lens micro-lens array and the like.

[0029] Compared with the prior art, the application has the following beneficial effects:

[0030] 1. The preparation method of the high refractive index precursor liquid provided by the present application controls the particle size of nano zirconium oxide inorganic particles by optimizing the synthesis method, specifically by selecting appropriate zirconium source, solvent A and additive components, then controlling the proportion among the three and related parameters (including but not limited to temperature, time, etc.) during the reaction, so that the particle size distribution of the obtained nano zirconium oxide inorganic particles is within a relatively narrow range, and the nano zirconium oxide inorganic particles are spherical with uniform size, so that the nano zirconium oxide inorganic particles are easy to modify in the subsequent ligand modification process, compared with the existing grinding method, the problem of uneven size and uneven shape of the nano zirconium oxide inorganic particles is solved, and the subsequent ligand modification is not uniform, thereby causing the high refractive index precursor liquid to have high haze, easy to agglomerate and settle, and other phenomena.

[0031] 2. The preparation method of the high refractive index precursor liquid provided by the present application, by selecting specific ligand B and ligand C to modify the synthesized nano zirconium oxide, reduces the viscosity of the high refractive index precursor liquid, improves the bonding ability with nano zirconium oxide, and also improves the compatibility with the resin or solvent system, so that the nano inorganic particles can be stably dispersed in the resin or solvent for a long time to maintain transparency, without precipitation and skinning phenomenon, and has good product stability. The reasons are as follows: on the one hand, ligand B is modified by selecting an organic carboxylic acid containing a long alkyl chain, which can exist completely independently in space between particles, ensuring that no agglomeration occurs; on the other hand, ligand C containing a photoreactive group (meth) acrylate structure can participate in the crosslinking of the resin when applied to a photocurable system, forming a tight network structure to encapsulate the nano zirconium oxide, while also reducing the viscosity of the system, ensuring the controllability of subsequent production.

[0032] 3. The preparation method of the high refractive index precursor liquid provided by the present application can adjust the double electron layer distribution on the surface of the nano inorganic particles by specific ligand modification, effectively improving the zeta potential of the nano zirconium oxide inorganic particles, so that the nano zirconium oxide inorganic particles have good stability in the resin or solvent system. After actual testing, there is no skinning phenomenon after being placed in air for half a year, and the system flowability, viscosity, light transmittance and other indicators do not change significantly, indicating that the precursor liquid has good stability, and the storage conditions are simple, which facilitates subsequent large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0033] The accompanying drawings incorporated in and forming a part of the specification, illustrate the principles of the application and are included for the purpose of explanation, rather than of limitation, as to the principles of the application.

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, for those skilled in the art, other drawings can also be obtained based on these drawings without any creative effort.

[0035] Figure 1 Flow chart for the preparation method of the high refractive precursor solution of the present application;

[0036] Figure 2 Transmission electron micrograph of the nano-zirconium oxide inorganic particles prepared in Example 1 of the present application under different magnifications;

[0037] Figure 3 XRD graph of the nano-zirconium oxide prepared in Example 1 of the present application;

[0038] Figure 4 Thermogravimetric analysis graph of the high refractive precursor solution prepared in Example 1 of the present application. DETAILED DESCRIPTION

[0039] The exemplary embodiments will be described in detail herein below, and the embodiments described in the following exemplary embodiments do not represent all the embodiments consistent with the present application. Rather, they are merely examples of devices consistent with some aspects of the present application as detailed in the appended claims.

[0040] In order to make the technical personnel in the art better understand the technical solutions of the present application, the present application will be further described in detail below in combination with the embodiments.

[0041] Example 1

[0042] In this embodiment, the zirconium source selected is zirconium oxychloride octahydrate, the solvent A selected is isopropyl alcohol, the additive selected is potassium carbonate, the ligand B selected is succinic acid, the ligand C selected is 3-(triallylsilyl) methyl methacrylate, and the solvent D selected is propylene glycol methyl ether acetate.

[0043] The preparation method of the high refractive precursor solution in this example includes the following steps:

[0044] 1) Zirconium oxychloride octahydrate and potassium carbonate are added into a reaction kettle according to a molar ratio of 1:1.1, and zirconium oxychloride octahydrate and isopropyl alcohol are added according to a mass ratio of 1:5, stirred uniformly, heated to 85℃, reacted for 12h, and then cooled to room temperature. After that, most of the solvent is removed by centrifugation, washed with ethanol or water, and calcined at 450℃ for 1h to obtain nano-zirconium oxide (powder).

[0045] 2) The nano-zirconium oxide obtained in step 1) and succinic acid are mixed and reacted at 75°C for 10h, and after the reaction is completed, centrifugation is performed, and ethanol is used for cleaning to remove the excess ligand and obtain an intermediate product, which is used as needed;

[0046] 3) The intermediate product obtained in step 2) is mixed with 3-(triallylsilyl) methyl propyl methacrylate and reacted at 55°C for 4h, and after the reaction is completed, centrifugation is performed, and ethanol is used for cleaning to remove the excess ligand and obtain the nano-zirconium oxide after all ligand treatment, which is used as needed; wherein in this embodiment, the mass ratio of the nano-zirconium oxide (powder), the ligand B (succinic acid) and the ligand C (3-(triallylsilyl) methyl propyl methacrylate) is 1:5:1;

[0047] 4) The nano-zirconium oxide after all ligand treatment is mixed with propylene glycol methyl ether acetate, and reacted by ultrasonic or heating stirring for 2h, and a small amount of insoluble nano-zirconium oxide inorganic particles is removed by centrifugation to obtain a dispersed, uniform and stable high-refractive precursor solution.

[0048] Figure 2 The transmission electron microscope image of the nano-zirconium oxide prepared in Example 1 can be seen that the particle size of the nano-zirconium oxide inorganic particles is between 5-10nm, and the morphology is a relatively uniform spherical shape with narrow particle size distribution, good dispersibility and no agglomeration phenomenon, which is conducive to the subsequent ligand modification process. The weight of the nano-zirconium oxide accounts for 35wt% of the total solid weight.

[0049] The refractive index of the high-refractive precursor solution is 1.4560 at 600nm and the transmittance is 98wt% by measuring by the ultraviolet-visible spectrophotometer, and the adhesion is tested by the hatch test method on a thick film, and the result is 1 / 100.

[0050] Figure 3 The XRD image of the nano-zirconium oxide prepared in Example 1 can be seen that there are characteristic peaks belonging to the cubic and tetragonal phase structure of ZrO2 near 30° and 35°, that is, at least 80% of the zirconium oxide is in a cubic structure and / or a tetragonal structure.

[0051] Figure 4 The thermogravimetric analysis image of the high-refractive precursor solution prepared in Example 1 can be seen that the theoretical solid content of the inorganic particles is 30.5%, but there is a certain error between the theoretical solid content and the actually measured solid content.

[0052] Example 2

[0053] In this embodiment, the zirconium source selected is zirconium chloride, the solvent A selected is water, the additive selected is potassium hydroxide, the ligand B selected is adipic acid, the ligand C selected is 2,3-dibromomethyl propyl methacrylate, and the solvent D selected is diacetone alcohol.

[0054] The preparation method of the high-refractive-index precursor solution of the present example comprises the following steps:

[0055] 1) zirconium chloride and potassium hydroxide were added into a reaction kettle according to a molar ratio of 1:2, and zirconium chloride and water were added according to a mass ratio of 1:6, which were stirred uniformly and heated to 100°C for 10h, and then cooled to room temperature. After that, most of the solvent was removed by centrifugation, and then the product was washed with ethanol or water, and calcined at 400°C for 2h to obtain nano-zirconia (powder).

[0056] 2) the nano-zirconia obtained in step 1) and adipic acid were mixed at 80°C for 12h, and then centrifuged. The intermediate product was obtained by washing with ethanol to remove the excess ligand.

[0057] 3) the intermediate product obtained in step 2) was mixed with 2,3-dibromomethyl propyl methacrylate at 60°C for 5h, and then centrifuged. The nano-zirconia treated with all ligands was obtained by washing with ethanol to remove the excess ligand. In the present example, the mass ratio of nano-zirconia (powder), ligand B (adipic acid) and ligand C (2,3-dibromomethyl propyl methacrylate) was 1:2:3.

[0058] 4) the nano-zirconia treated with all ligands was mixed with diacetone alcohol, and reacted by ultrasonic or heating stirring for 2h. A small amount of insoluble nano-zirconia inorganic particles was removed by centrifugation, and a dispersion, uniform and stable high-refractive-index precursor solution was obtained.

[0059] Example 3

[0060] In the present example, the zirconium source was zirconium n-propylate, the solvent A was benzyl alcohol, the additive was sodium carbonate, the ligand B was heptanedioic acid, the ligand C was 3-chloro-2-hydroxypropyl methacrylate, and the solvent D was N-methyl pyrrolidone.

[0061] The preparation method of the high-refractive-index precursor solution of the present example comprises the following steps:

[0062] 1) zirconium n-propylate and sodium carbonate were added into a reaction kettle according to a molar ratio of 1:1.5, and zirconium n-propylate and benzyl alcohol were added according to a mass ratio of 1:8, which were stirred uniformly and heated to 150°C for 10h, and then cooled to room temperature. After that, most of the solvent was removed by centrifugation, and then the product was washed with ethanol or water, and calcined at 480°C for 0.5h to obtain nano-zirconia (powder).

[0063] 2) the nano-zirconia obtained in step 1) and heptanedioic acid were mixed at 85°C for 12h, and then centrifuged. The intermediate product was obtained by washing with ethanol to remove the excess ligand.

[0064] 3) The intermediate product obtained in step 2) is mixed with 3-chloro-2-hydroxypropyl methacrylate at 60°C for 6h, after the reaction is completed, centrifugation is performed, and ethanol is used for cleaning to remove the excess ligand and obtain the nano-zirconia treated with all ligands, which is ready for use; wherein, in this embodiment, the mass ratio of the nano-zirconia (powder), the ligand B (heptanedioic acid), and the ligand C (3-chloro-2-hydroxypropyl methacrylate) is 1:5:5;

[0065] 4) The nano-zirconia treated with all ligands is mixed with N-methylpyrrolidone, and the reaction is performed through ultrasonic or heating stirring for 2h, a small amount of nano-zirconia inorganic particles that are not dissolved is removed through centrifugation, and a dispersed, uniform, and stable high-refractive precursor solution is obtained.

[0066] Example 4

[0067] In this embodiment, the zirconium source is zirconyl nitrate, the solvent A is benzyl alcohol, the additive is potassium tert-butoxide, the ligand B is n-octanoic acid, the ligand C is 3-methacryloyloxypropylmethyldimethoxysilane, and the solvent D is N,N-dimethylformamide.

[0068] The preparation method of the high-refractive precursor solution in this example includes the following steps:

[0069] 1) Zirconyl nitrate and potassium tert-butoxide are added into a reaction kettle according to a molar ratio of 1:1.5, and zirconyl nitrate and benzyl alcohol are added according to a mass ratio of 1:10, the mixture is uniformly stirred and heated to 180°C for reaction for 14h, and then cooled to room temperature, most of the solvent is removed through centrifugation, cleaned with ethanol or water, and calcined at 500°C for 2h to obtain nano-zirconia (powder).

[0070] 2) The nano-zirconia obtained in step 1) and n-octanoic acid are mixed at 85°C for reaction for 12h, after the reaction is completed, centrifugation is performed, and ethanol is used for cleaning to remove the excess ligand and obtain an intermediate product, which is ready for use;

[0071] 3) The intermediate product obtained in step 2) is mixed with 3-methacryloyloxypropylmethyldimethoxysilane at 75°C for reaction for 8h, after the reaction is completed, centrifugation is performed, and ethanol is used for cleaning to remove the excess ligand and obtain the nano-zirconia treated with all ligands, which is ready for use; wherein, in this embodiment, the mass ratio of the nano-zirconia (powder), the ligand B (n-octanoic acid), and the ligand C (3-methacryloyloxypropylmethyldimethoxysilane) is 1:6:8;

[0072] 4) The nano-zirconia treated with all ligands is mixed with N,N-dimethylformamide, and the reaction is performed through ultrasonic or heating stirring for 2h, a small amount of nano-zirconia inorganic particles that are not dissolved is removed through centrifugation, and a dispersed, uniform, and stable high-refractive precursor solution is obtained.

[0073] Comparative Example 1

[0074] The only difference between this comparative example and Example 1 is that in this comparative example, no calcination is used in the preparation of nano-zirconium oxide in step 1).

[0075] Comparative Example 2

[0076] The only difference between this comparative example and Example 1 is that in this comparative example, the ligand B is selected as nitric acid with a mass fraction of 68wt%.

[0077] Comparative Example 3

[0078] The only difference between this comparative example and Example 1 is that in this comparative example, the ligand C is selected as n-propyl trimethoxysilane.

[0079] Comparative Example 4

[0080] The only difference between this comparative example and Example 1 is that in this comparative example, the solvent D is selected as carbon tetrachloride.

[0081] In order to further verify the effectiveness of the preparation method of the present application, the inventors tested the properties of the precursor solutions prepared in Examples 1-4 and Comparative Examples 1-4, and the specific results are shown in Table 1 below:

[0082]

[0083] As can be seen from the property test data in Table 1, the specific ligand modification of the present application can adjust the distribution of the double electron layer on the surface of the nano-zirconium oxide inorganic particles, effectively improve the zeta potential of the particles compared to Comparative Examples 1-4, and make the particles have good stability in the resin or solvent system. The introduction of organic carboxylic acid can effectively change the double electron layer structure of the inorganic particles, so that the absolute value of the zeta potential of the particles is improved, thereby improving the stability of the particles when dispersed in the solution. At the same time, by introducing unsaturated groups (usually double bonds), the inorganic particles can be effectively fixed in the chain or network structure formed during the resin curing process, thereby avoiding zirconium enrichment.

[0084] Under the condition that the doping amount (solid content) of the system is close, the haze of Examples 1-4 is relatively low, only about 20, and the refractive index is relatively high, about 1.456. The haze of the system of Comparative Examples 2-4 is as high as 55, the acid value is lower than that of the inventive examples, and the lowest is 1mgKOH / g. At the same time, the refractive index of the system of Comparative Examples is also relatively low.

[0085] Specifically, when preparing nano-zirconium oxide in Comparative Example 1, calcination is not used, and the content of nano-zirconium oxide monoclinic grains is high, so the refractive index of the system is lower than that of Example 1, while the mass of the tetragonal and cubic grain structures of the nano-zirconium oxide calcined in Example 1 is more than 80% of the nano-zirconium oxide, which is beneficial to improve the refractive index of the system. Through ligand exchange, the inorganic particles can be stably in the resin or solvent for a long time, without precipitation and skinning phenomenon, and the product stability is good.

[0086] The ligand B selected in Comparative Example 2 is nitric acid, the system becomes brown, the small molecule acid is too tight for anchoring, the acid value is too large, which is not conducive to subsequent compounding, the inorganic acid cannot be modified on the surface, and the particles have a tendency to agglomerate in space, which affects the refractive index and the performance of the final product.

[0087] The ligand C selected in Comparative Example 3 is n-propyl trimethoxysilane, which does not contain a photocurable group and does not participate in the crosslinking of the resin during subsequent photocuring, so it cannot form a network structure, which affects the haze of the system. However, the ligand of the present application is used in combination, two ligands are introduced on the surface of the particles, ligand B can improve crosslinking, the viscosity significantly increases after introduction, and the purpose of introducing ligand C is to promote crosslinking and reduce the viscosity of the system.

[0088] The solvent D selected in Comparative Example 4 is carbon tetrachloride, which has poor solubility with inorganic bases, and the nucleation effect is poor during the cooling process of the system, which affects the size and uniformity of the particle size.

[0089] The above description is only a specific embodiment of the present application, which enables those skilled in the art to 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.

[0090] It should be understood that the present application is not limited to the above described and that various modifications and changes can be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A method for preparing a high refractive index precursor liquid, characterized in that, It includes the following steps: Step 1: First, add the zirconium source, solvent A and additives into the reaction vessel according to the reaction equivalence ratio, mix evenly and heat to a temperature of 78-200℃, react for 10-14 hours and then cool to room temperature; then centrifuge, wash with ethanol or water, and finally calcine at a temperature of 400-500℃ for 0.5-2 hours to obtain nano-zirconia. Step 2: React the nano-zirconia obtained in Step 1 with ligand B at a temperature of 75-175℃ for 10-14 hours. After the reaction is completed, centrifuge the mixture and then wash it with ethanol to obtain the intermediate product. Step 3: React the intermediate product obtained in Step 2 with ligand C at a temperature of 55-155℃ for 4-8 hours. After the reaction is completed, centrifuge the product and wash it with ethanol to obtain the ligand-treated nano-zirconia. Step 4: After mixing the nano-zirconia treated with ligands in Step 3 with solvent D and reacting, the mixture is then centrifuged to obtain the target product, a high-refractive-index precursor solution. The mass ratio of nano-zirconia in step one, ligand B in step two, and ligand C in step three is 1:(0.1-10):(0.1-10). The reaction equivalence ratio is: the molar ratio of zirconium source to additive is 1:(1~3), and the mass ratio of zirconium source to solvent A is 1:(1~10); after calcination, the nano-zirconia contains tetragonal and / or cubic phase grain structures, and the mass of the tetragonal and / or cubic phase grain structures accounts for more than 80% of the nano-zirconia. Solvent A is any one of isopropanol, water, and benzyl alcohol; The additive is one or more of the following: sodium hydroxide, potassium hydroxide, potassium carbonate, sodium carbonate, sodium bicarbonate, cesium carbonate, ammonia, ammonium bicarbonate, sodium tert-butoxide, potassium tert-butoxide, sodium methoxide, sodium ethoxide, diethylamine, triethylamine, pyridine, and diisopropylamine. The ligand B is selected from organic carboxylic acids containing long alkyl chains; The ligand C is selected from acrylate compounds containing photocurable groups; The solvent D is any one of acetone, 1,1-dichloroethane, tetrahydrofuran, ethyl acetate, ethanol, cyclohexane, acetonitrile, 1,2-dichloroethane, ethylene glycol dimethyl ether, 1,4-dioxane, toluene, propylene glycol methyl ether acetate, N,N-dimethylformamide, N-methylformamide, N-methylpyrrolidone, dimethyl sulfoxide, diacetone alcohol, hexamethylphosphotriamide, and glycerol; The high-refractive-index precursor liquid has a zeta potential of -47mV, -48mV, -52mV, and -58mV, a refractive index of 1.4560, 1.4563, and 1.4564, and a haze of 15, 18, 22, and 24, and is used to prepare optical materials.

2. The method for preparing the high refractive index precursor liquid according to claim 1, characterized in that, In step one, the zirconium source is one or more of the following: zirconium oxychloride octahydrate, zirconium chloride, zirconium nitrate, zirconium oxynitrate, basic zirconium carbonate, zirconium trifluoroacetate, zirconium n-propoxide, zirconium isopropoxide, zirconium n-butoxide, zirconium succinate, and zirconium pyrophosphate.

3. The method for preparing the high refractive index precursor liquid according to claim 1, characterized in that, The organic carboxylic acid is one or more of the following: formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, neovaleric acid, octanoic acid, decanoic acid, stearic acid, palmitic acid, lauric acid, myristic acid, palmitic acid, arachidic acid, oleic acid, linoleic acid, linolenic acid, arachidonic acid, succinic acid, adipic acid, methacrylic acid, pimelic acid, and octanoic acid.

4. The method for preparing the high refractive index precursor liquid according to claim 1, characterized in that, The photocurable acrylate compounds are methacrylates, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, allyl methacrylate, butyl methacrylate, isobutyl methacrylate, 3-(triallylsilyl)propyl methacrylate, 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propyl methacrylate, 1,3-di(4-benzoyl-3-hydroxyphenoxy)propyl-2-ylmethacrylate, 2,3-dibromopropyl methacrylate, 3-(3,5,7,9,11,13,1... 5-Heptacyclopentylpentyl-cyclooctylsiloxane)propyl methacrylate, 3-(dimethylamino)propyl methacrylate, 3-methacryloyloxypropyldimethylethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, methacryloyloxypropylmethyldiethoxysilane, 3-chloro-2-hydroxypropyl methacrylate, bis-3-methacryloyloxypropyltetramethyldisiloxane, methacryloyloxypropyltriethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, methacryloyloxypropyltri(trimethylsiloxane)silane, or one or more of these.

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