TWI760244B - Nano zirconia powder, preparation method thereof and dispersion liquid and optical film prepared therefrom - Google Patents

Abstract

The present invention provides a nano zirconia powder having a particle size in a range of 3-10 nm and a specific surface area in a range of 200-240 m²/g. The nano zirconia powder comprises a tetragonal crystal zirconia and others, wherein the amount proportion of the tetragonal crystal zirconia is in a range of 60-95% with respect to total amount of the powder. The nano zirconia powder provided by the present invention is characterized in having characteristics such as small particle size, large specific surface area, good particle dispersion effect, and tetragonal crystal being as the main crystal phase. The aqueous dispersion obtained from being dispersed in water can greatly increase the refractive index of a high-refractive coating and improve the performance of the film when being used in a subsequent preparation of a brightening film or an anti-reflection film.

Description

Nano zirconia powder, its preparation method and obtained dispersion liquid, optical film

The invention belongs to the field of fine chemical industry, and particularly relates to a nano-zirconia powder, a preparation method thereof, a dispersion liquid obtained therefrom, and an optical film.

In recent years, by combining zirconia particle dispersion with transparent resin or film, it has been well used in the field of optics by taking advantage of its high refractive index. For example, high-refractive zirconia dispersion is used to prepare optical films such as brightness enhancement film and anti-reflection film, which can be used on LCD displays to increase the brightness and clarity of the screen; it can also be used to improve the refractive index of LED sealing resin, which can more effectively The light emitted by the light-emitting body is extracted, and the brightness of the LED is further improved. In conclusion, its high refractive properties can be used in high refractive coatings for applications in different fields.

The refractive index of the zirconia dispersion is closely related to the particle size, crystal structure, particle dispersion state and preparation process of the nano-zirconia in the system. CN108529674A discloses a preparation method of high-dispersion nano-zirconia particles and transparent dispersions thereof. The nano-zirconia particles are directly prepared by pyrolyzing inorganic zirconium salts in a hypergravity environment, and with the increase of the hypergravity level The agglomeration is greatly reduced, and after washing and modification, it is directly a transparent liquid dispersion of zirconia. Although the zirconia prepared by this method has small particle size and good dispersibility, its powder crystal structure is a monoclinic phase, and the refractive index of the powder is much lower than that of the tetragonal powder, and the corresponding liquid phase The refractive index of the dispersion is also lower under the same conditions. Therefore, how to prepare nano-zirconia particles with excellent performance and zirconia dispersion with stable system, uniform dispersion and high refractive index is particularly important to better meet the performance requirements of transparent organic-inorganic composites.

The invention provides a nano-zirconia powder, a preparation method thereof, a dispersion liquid and an optical film obtained therefrom, and the specific technical solutions are as follows: a nano-zirconia powder, characterized in that the particles of the nano-zirconia powder are The diameter is 3-10nm, the specific surface area is 200-240m ² /g, the nano-zirconia powder includes zirconia with tetragonal crystal structure, and the proportion of zirconia with tetragonal crystal structure accounts for 60- 95%.

The present invention also provides a method for preparing nano-zirconia powder according to the above technical scheme, comprising the following steps: dissolving zirconium salt and stable element salt together in water to obtain solution A; dissolving alkali in water, Obtain solution B; fully mix solution A and solution B under stirring to form a precipitate, wherein the mass of the precipitate accounts for 1-40% of the total mass of the mixed solution; after the precipitate is washed and filtered for many times, the precursor is obtained material C; adding water and organic acid or its salt to the precursor C to make a slurry, the total solid content in the obtained slurry is 6-20wt%; the above-mentioned obtained slurry is put into the reaction kettle, and the filling amount is 60 -90%, hydrothermally react at 180°C-220°C for 1-12 hours, and obtain a reaction solution after the reaction; directly dry the reaction solution or concentrate, wash and then dry to obtain nano-zirconia powder.

Preferably, the added zirconium salt is a water-soluble zirconium salt, selected from at least one of basic carbonate, carbonate, nitrate, acetate, chloride, and oxychloride; the added stable element salt is stable Chloride or nitrate of a natural element, wherein the stabilizing element is selected from at least one of aluminum, magnesium, titanium and rare earth elements; the base is selected from ammonia, sodium hydroxide, potassium hydroxide and lithium hydroxide at least one of.

2mol/L，所加入的穩定性元素與鋯元素的莫耳濃度比為2/98~30/70，所加入的鹼的濃度為

8mol/L。 Preferably, the added zirconium salt concentration

2mol/L, the molar concentration ratio of the added stability element and the zirconium element is 2/98~30/70, and the added concentration of the alkali is

8mol/L.

Preferably, the organic acid is selected from at least one of monocarboxylic acid, polycarboxylic acid and hydroxycarboxylic acid, wherein the monocarboxylic acid is selected from at least one of formic acid, acetic acid, propionic acid and butyric acid, and polycarboxylic acid is selected from at least one of formic acid, acetic acid, propionic acid and butyric acid. The acid is selected from at least one of oxalic acid, malonic acid, succinic acid and phthalic acid, and the hydroxycarboxylic acid is selected from at least one of lactic acid, malic acid, tartaric acid and citric acid; the salt of the organic acid is its alkali metal Salt, at least one selected from potassium salt and sodium salt.

Preferably, the molar concentration of the added organic acid or its salt is 10-100% of the sum of the molar concentration of the zirconium element and the stabilizing element.

Preferably, when the boiling point of the added organic acid is less than 150°C, the reaction solution is directly dried to obtain nano-zirconia powder; when the boiling point of the added organic acid is greater than 150°C, the reaction solution is concentrated and washed for many times. and then dried to obtain nano-zirconia powder.

Preferably, the drying method is selected from any one of vacuum low-temperature drying, drying and spraying, and the concentrated washing method is selected from any one of ultrafiltration, rotary evaporation and ceramic membrane concentrated washing.

The present invention also provides an organic solvent-based dispersion liquid containing the nano-zirconia powder according to the above technical solution, the content of the nano-zirconia in the dispersion liquid is 40-70wt%, and the refractive index is 1.400-1.554.

Preferably, when the content of the nano-zirconia contained in the dispersion is 70 wt %, the refractive index of the dispersion is not lower than 1.554.

Preferably, the dispersion liquid is obtained by replacing the dispersion medium water in the reaction liquid obtained by the preparation method described in the above technical scheme with an organic solvent, or the nano-zirconia prepared by the above technical scheme The powder is obtained by dispersing in an organic solvent, wherein the organic solvent is selected from at least one of alcohols, esters, aromatic hydrocarbons, ethers and amide organic solvents.

Preferably, a modifier is added to the dispersion, and the addition amount of the modifier is 1-20wt% of the content of the nano-zirconia.

Preferably, the modifier is selected from at least one of silane coupling agents, titanate coupling agents, metal complexes, aromatic or highly conjugated chemical substances.

Preferably, an oily dispersing aid is added to the dispersion, and the amount of the oily dispersing aid is 1-20 wt % of the content of the nano-zirconia.

The present invention also provides a nano-zirconia dispersion liquid with a photocurable resin. The dispersion liquid is obtained by adding the photocurable resin to the dispersion liquid of the nano-zirconia powder described in any of the above technical solutions. , obtained after removing the organic solvent by distillation under reduced pressure; The content of nano-zirconia in the dispersion liquid is 50-80wt%, and the refractive index thereof is 1.60-1.70.

Preferably, the added amount of the photocurable resin is 20-50% of the total mass of the zirconia and the photocurable resin.

The present invention also provides an optical film, which adopts the dispersion liquid containing nano-zirconia powder described in any one of the above technical solutions or the nano-sized photocurable resin described in any one of the above technical solutions. A zirconia dispersion was prepared.

The present invention also provides a nano-zirconia powder according to the above technical solution or a dispersion liquid containing nano-zirconia powder according to any one of the above technical solutions or any one of the above technical solutions. The application of nano-zirconia dispersion with photocurable resin in the preparation of optical film.

Compared with the prior art, the beneficial effects of the present invention are:

1. The nano-zirconia powder provided by the present invention has the characteristics of small particle size, large specific surface area, good particle monodispersion effect, and the main crystal phase is tetragonal;

2. The organic solvent type and photocurable resin type dispersion liquid prepared by using the above-obtained nano-zirconia powder has stable system, uniform dispersion, high dispersion liquid concentration and high refractive index.

3. The use of the dispersion liquid with the above characteristics can greatly increase the refractive index of the high-refractive coating and improve the performance of the film in the subsequent preparation of, for example, a brightness enhancement film or an anti-reflection film.

Fig. 1a is a transmission electron microscope Fig. 1 of the nano-zirconia powder provided by the embodiment 1 of the present invention; Fig. 1b is a transmission electron microscope Fig. 2 of the nano-zirconia powder provided by the embodiment 1 of the present invention; The XRD comparison pattern of the nano-zirconia powder provided in Example 1 of the present invention and the standard tetragonal phase grains; FIG. 3 is a particle size distribution diagram of the nano-zirconia powder provided in Example 1 of the present invention; FIG. 4 is a Scanning electron microscope image of the nano-zirconia powder provided in Comparative Example 1 of the present invention.

The technical solutions of the present invention will be described in detail below with reference to specific embodiments, however, it should be understood that elements, structures and features in one embodiment can also be beneficially combined into other embodiments without further description.

It should be understood that although embodiments may show a particular order of method steps, this does not require or imply that the operations must be performed in that particular order, or that all illustrated operations must be performed to achieve desired results , instead, the steps can change the order of execution. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined to be performed as one step, and/or one step may be decomposed into multiple steps to be performed. Unless otherwise specified or the relationship between steps determines the order of execution. Such deformation will depend on the choice. All such variations are within the scope of this disclosure.

The described embodiments are only to describe the preferred embodiments of the present invention, not to limit the scope of the present invention. On the premise of not departing from the design spirit of the present invention, various modifications and variations of the technical solutions of the present invention made by those of ordinary skill in the art can be made. Improvements should all fall within the protection scope determined by the scope of the patent application of the present invention.

An embodiment of the present invention provides a nano-zirconia powder, the particle size of the nano-zirconia powder is 3-10 nm, the specific surface area is 200-240 m ² /g, and the nano-zirconia powder is It includes zirconia with tetragonal crystal structure, and the proportion of zirconia with tetragonal crystal structure accounts for 60-95% of the powder.

The nano-zirconia powder provided by this embodiment has small particle size, large specific surface area and high refractive index, and can prepare a nano-zirconia dispersion liquid with uniform dispersion and high refractive index. The nano-zirconia powder provided by the above embodiment, the synergistic effect of its particle size, specific surface area and the proportion of the tetragonal crystal structure can make the obtained nano-zirconia powder have uniform dispersion and high refractive index after dispersion. The characteristics are that when the particle size is small and the specific surface is large, the particle dispersibility is good, the prepared aqueous dispersion will be uniformly dispersed, and the refractive index will be higher; and when the zirconia crystal phase is tetragonal and powdery. The higher the proportion of the tetragonal phase in the bulk, the higher the corresponding refractive index (the refractive index of zirconia in the tetragonal phase is 2.40, which is significantly higher than the refractive index of zirconia in the monoclinic phase, which is 2.02). It can be understood that the particle size of the nano-zirconia powder can also be 4, 5, 6, 7, 8, 9 nm or any value within the above range, and the specific surface area can also be 205, 210, 215, 220, 225, 230, 235m ² /g or any value in the above range, the proportion of the tetragonal crystal structure in the powder can also be 65, 70, 75, 80, 85, 90% or any value in the above range .

Another embodiment of the present invention also provides the method for preparing nano-zirconia powder described in the above embodiment, which includes the following steps: dissolving zirconium salt and stable element salt together in water to obtain solution A; dissolving alkali In water, solution B was obtained; the solution A and solution B were fully mixed under stirring to form a precipitate, wherein the mass of the precipitate accounted for 1-40% of the total mass of the mixed solution; the precipitate was washed and filtered for many times. , obtain the precursor C; add water and organic acid or its salt to the precursor C to make a slurry, the total solid content in the obtained slurry is 6-20wt%; put the obtained slurry into the reaction kettle, fill The amount is 60-90%, and the hydrothermal reaction is carried out at 180-220 °C for 1-12 hours, and a reaction solution is obtained after the reaction; the reaction solution is directly dried or concentrated, washed and then dried to obtain nano-zirconia powder.

In the preparation method of nano-zirconia powder defined by the above-mentioned embodiment, the order of adding the organic acid or its salt is different from the prior art, that is, the organic acid or its salt needs to be introduced before making the slurry instead of after making the slurry. This is because the viscosity of the precursor will be greatly reduced in the process of making the slurry due to the action of the electric charge before the slurry is made, which can not only improve the dispersion effect of the slurry, but also improve the introduction of the precursor into the kettle. The concentration of the slurry avoids the poor dispersion effect of the slurry, This results in defects such as high particle size of the prepared powder, agglomeration, and difficulty in dispersion. In addition, it has been reported in the prior art that the hydrothermal reaction can be carried out above 170°C, and in this embodiment, the temperature is limited within the range of 180-220°C, such as 190°C, 195°C, 200°C, 205°C, 210°C , 215°C or any value within the above range. The temperature of the hydrothermal reaction in the preparation method provided by this embodiment directly affects the crystal grain structure of the obtained powder, that is, if it is less than 180° C., for example, 170° C., the crystal form of the obtained powder is a monoclinic phase grain structure, while Unexpected tetragonal crystal structure; and if it is >220 °C, it will have strict requirements on production equipment, which is not conducive to scale-up production.

In a preferred embodiment, the added zirconium salt is a water-soluble zirconium salt selected from at least one of basic carbonate, carbonate, nitrate, acetate, chloride and oxychloride; the added stability The elemental salt is a chloride or nitrate of a stabilizing element, wherein the stabilizing element is selected from at least one of aluminum, magnesium, titanium and rare earth elements; the base is selected from ammonia, sodium hydroxide, potassium hydroxide and At least one of lithium hydroxide.

2mol/L，所加入的穩定性元素與鋯元素的莫耳濃度比為2/98~30/70，所加入的鹼的濃度為

8mol/L。可以理解的是，上述所加入的穩定性元素的量需進行嚴格控制，不宜過多或過少，這是因為過少易使製備得到的粉體的四方相占比較小甚至為單斜相，過多則易使製備得到的粉體中穩定性元素含量高而影響粉體本身折射率。通過控制所加入的鋯鹽濃度和穩定性元素鹽的量，進而嚴格控制溶液A中穩定性元素與鋯元素的莫耳濃度比。 In a preferred embodiment, the added zirconium salt concentration

2mol/L, the molar concentration ratio of the added stability element and the zirconium element is 2/98~30/70, and the added concentration of the alkali is

8mol/L. It can be understood that the amount of the above-mentioned added stabilizing elements needs to be strictly controlled, and it should not be too much or too little. This is because too little is easy to make the tetragonal phase of the prepared powder smaller or even monoclinic. The content of stabilizing elements in the prepared powder is high to affect the refractive index of the powder itself. By controlling the added zirconium salt concentration and the amount of the stabilizing element salt, the molar concentration ratio of the stabilizing element and the zirconium element in solution A is strictly controlled.

In a preferred embodiment, the organic acid is selected from at least one of monocarboxylic acid, polycarboxylic acid and hydroxycarboxylic acid, wherein the monocarboxylic acid is selected from formic acid, acetic acid, propionic acid and butyric acid At least one, the polycarboxylic acid is at least one selected from oxalic acid, malonic acid, succinic acid, and phthalic acid, and the hydroxycarboxylic acid is selected from lactic acid, malic acid, tartaric acid, citric acid At least one of citric acid; the salt of the organic acid is its alkali metal salt, selected from at least one of potassium salt and sodium salt.

In a preferred embodiment, the molar concentration of the added organic acid or its salt is 10-100% of the sum of the molar concentration of the zirconium element and the stabilizing element. It can be understood that the content of the organic acid and its salt is clearly defined in this example, and the molar concentration of the organic acid and its salt is limited to 10-100% of the sum of the molar concentration of zirconium element and stabilizing element. The reason is that, in the prior art (for example, Chinese patent application number CN102264645A), when preparing the zirconia dispersion, the amount of the organic acid added is usually more than 1 times the zirconium molar concentration, but when the organic acid, especially the molecular weight, is larger The addition amount is too large. On the one hand, the acidity of the reaction slurry is highly corrosive to the reaction equipment. On the other hand, the preparation of the aqueous dispersion in the later stage needs to be concentrated and washed with a large amount of water for many times. The greater the probability of residual acid in the solvent-based dispersion prepared in the later stage, the greater the probability of industrial production. Therefore, in this embodiment, the amount is limited within the range of 10-100% through the optimization of the overall scheme. Preferably, the molar concentration of the organic acid and its salt can be 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% of the sum of the molar concentration of zirconium element and stabilizing element or the above range any value within.

In a preferred embodiment, when the boiling point of the organic acid added is less than 150°C, the reaction solution is directly dried to obtain nano-zirconia powder; when the boiling point of the organic acid added is greater than 150°C, the reaction solution is heated After concentrating and washing, and then drying, the nano-zirconia powder is obtained. It can be understood that the organic acid with a boiling point of <150°C can be selected from, for example, formic acid, acetic acid, propionic acid, etc., and the organic acid with a boiling point of >150°C can be selected from, for example, oleic acid, citric acid, isovaleric acid, etc., which are only listed here. There is no specific limitation.

In a preferred embodiment, the drying method is selected from any one of vacuum low-temperature drying, drying and spraying, and the concentrated washing method is selected from any one of ultrafiltration, rotary evaporation and ceramic membrane concentrated washing. It can be understood that the above drying methods and concentrated washing methods are both The operation mode is well known to those skilled in the art, and the specific requirements under the specific mode can be selected or adjusted according to the actual situation.

An embodiment of the present invention also provides an organic solvent-based dispersion containing the nano-zirconia powder described in the above embodiment, the content of the nano-zirconia in the dispersion is 40-70wt%, and the refractive index is 1.400-1.554. It can be understood that the content of the nano-zirconia in the obtained organic solvent-based dispersion is significantly improved compared to the content of the nano-zirconia in the prior art, which belongs to the organic solvent-based dispersion of high-concentration nano-zirconia, The content of nano-zirconia in the dispersion can also be 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 , 60, 61, 62, 63, 64, 65, 66, 67, 68, 69 wt% or any value within the above range.

In a preferred embodiment, the dispersion liquid is obtained by replacing the dispersion medium (ie, water) in the reaction liquid obtained by the preparation method described in the above-mentioned embodiment with an organic solvent, or by replacing the above-mentioned embodiment with an organic solvent. The nano-zirconia powder prepared by the method is obtained by dispersing in an organic solvent, wherein the organic solvent is selected from at least one of alcohols, esters, aromatic hydrocarbons, ethers and amide organic solvents.

It can be understood that: above-mentioned alcohols can be selected from at least one in methanol, ethanol, propanol, n-butanol; ketones can be selected from at least one in acetone, butanone, methyl isobutyl ketone; esters can be selected from From ethyl acetate or butyl acetate; aromatic hydrocarbons can be selected from at least one of toluene, xylene and ethylbenzene; ethers can be selected from propylene glycol methyl ether, ethylene glycol monomethyl ether, diethylene glycol monobutyl ether At least one of the amides; the amides can be selected from at least one of dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone.

In a preferred embodiment, a modifier is added to the dispersion, and the amount of the modifier is 1-20 wt % of the content of the nano-zirconia. In this embodiment, the modifier is added for secondary dispersion, the purpose is to make the nanometer Zirconia can be fully dispersed. It can be understood that the addition amount of the modifier can also be 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt% of the nano-zirconia content %, 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt% or any value within the above range.

In a preferred embodiment, the modifier is selected from at least one of silane coupling agents, titanate coupling agents, metal complexes, aromatic or highly conjugated chemical substances. Wherein, the silane coupling agent and titanate coupling agent are not specifically limited here, and can be commercially available coupling agents of various labels; the metal complex can be selected from zirconium, titanium, aluminum, zinc, indium and tin Metal complexes of at least one metal and at least one ligand selected from the group consisting of acetylacetone, trifluoroacetone and hexafluoroacetone (such as acetylacetonate titanium, acetoacetone aluminum); in addition, The modifier can also be an aromatic or highly conjugated substance, and can be selected from at least one of 1-styrene acetone, phenylacetylacetone, diphenylacetic acid, phenylphosphinic acid, and triphenyl phosphate .

In a preferred embodiment, an oily dispersing aid is added to the dispersion, and the amount of the oily dispersing aid is 1-20 wt % of the content of the nano-zirconia. It can be understood that the purpose of adding an oil-based dispersing aid in this embodiment is to further improve the stability and dispersibility of the dispersion. The dispersing aid here is not specifically limited, and can be commercially available anionic dispersants, cationic dispersants At least one of dispersants, nonionic dispersants and polymer dispersants, preferably phosphate series dispersing aids.

In a preferred embodiment, the organic solvent-based dispersion of the nano-zirconia is obtained by adding organic The solvent is subjected to rotary evaporation treatment, concentrated to remove water, and then an organic solvent is added. After repeated dilution and concentration, a zirconia organic solvent-type dispersion is obtained.

In the above preferred embodiment, after the water of the dispersion medium in the reaction solution obtained in the preparation process of the preparation method described in the above embodiment is replaced with an organic solvent, the further A modifier is added for lipophilic modification, and an oil-based dispersing aid is also added to strengthen the stability and dispersibility of the dispersion. Compared with the dispersion liquid in which the dispersion medium is replaced in the prior art, the dispersion liquid treated in this way has significant advantages.

Another embodiment of the present invention also provides a nano-zirconia dispersion liquid with a photocurable resin, the dispersion liquid is adding the photocurable resin to the nano-zirconia powder described in any one of the above embodiments In the dispersion liquid, the organic solvent is removed by distillation under reduced pressure to obtain; the content of nano-zirconia in the dispersion liquid is 50-80wt%, and the refractive index is 1.60-1.70. It will be appreciated that the photocurable resin employed is one containing one or more radiation polymerizable double bonds, and the photocurable resin may be selected from the group consisting of esters, urethanes, ethers, silicon, halogens and/or containing (meth)acrylic monomers or oligomers of phosphorus and other groups. A photocurable resin with a relatively high refractive index, such as an acrylate containing an alicyclic skeleton (dicyclopentyl methacrylate, cyclohexyl acrylate), is preferred. Or preferably light-curable resins with lower viscosity, such as benzyl acrylate and methyl (meth)acrylate. The photocurable resin may be a commercially available monomer or oligomer.

In a preferred embodiment, the added amount of the photocurable resin is 20-50% of the total mass of the zirconia and the photocurable resin.

The present invention also provides an optical film using the dispersion liquid containing nano-zirconia powder according to any of the above embodiments or the nano-zirconia dispersion liquid with photocurable resin according to any of the above-mentioned embodiments prepared. It can be understood that the optical films provided in this embodiment can mainly be brightness enhancement films, anti-reflection films, and other optical films with high-refractive coatings.

The present invention will be described in detail below with reference to the embodiments. It should be understood that these embodiments are only some preferred embodiments of the present invention, and should not be construed as limiting the protection scope of the present invention.

"Example 1"

Weigh 1.47kg of zirconium oxychloride and 138g of yttrium chloride and dissolve in 8kg of water to obtain mixed solution A; 421g of sodium hydroxide is dissolved in 6kg of water to obtain sodium hydroxide solution B; solution A and solution B are fully stirred under stirring After mixing, a precipitate is formed, and the precipitate is washed and filtered for several times to obtain a precursor C; water and 270 g of acetic acid are added to the precursor C (the amount of acetic acid is 90% of the sum of the amount of zirconium element and stable element material. , therefore, the molar concentration of acetic acid is 90% of the sum of zirconium element and stabilizing element molar concentration), the total volume is controlled at 8L, and the slurry is stirred and made into slurry; the above-mentioned obtained slurry is put into the 10L reactor, and placed in 200 The hydrothermal reaction is carried out at ℃ for 3 hours; after the reaction is completed, the reaction solution is directly dried to obtain nano-zirconia powder.

The obtained nano-zirconia powder has a particle size of 3-10 nm, a specific surface area of 220 m ² /g, and the nano-zirconia powder is zirconia with a tetragonal crystal structure, and the The proportion of zirconia accounts for more than 90% of the powder, as shown in Figure 1-3. It can be seen from Figure 1a and Figure 1b that the particle size of the obtained nano-zirconia powder is 3-10nm. It can be seen from Figure 2 that the diffraction peak of the upper nano-zirconia powder and the XRD of the lower standard tetragonal phase grains The characteristic peaks correspond, and the proportion of the tetragonal crystal structure is relatively high. By analyzing and calculating the diffraction intensity data, it can be found that the proportion of the tetragonal crystal structure is more than 90%.

"Example 2"

Weigh 1.47kg of zirconium oxychloride and 69g of yttrium chloride and dissolve in 8kg of water to obtain mixed solution A; 550g of sodium hydroxide is dissolved in 6kg of water to obtain potassium hydroxide solution B; solution A and solution B are fully stirred under stirring After mixing, a precipitate is formed, and the precipitate is washed and filtered for several times to obtain the precursor C; Add water and 160 g of acetic acid to the precursor C (the amount of acetic acid is 56% of the sum of the amount of zirconium element and stabilizing element material), control the total volume to 8L, and stir to make a slurry; put the above-obtained slurry into In a 10L reaction kettle, the hydrothermal reaction was carried out at 180° C. for 4 hours; after the reaction was completed, the reaction solution was directly dried to obtain nano-zirconia powder.

The obtained nano-zirconia powder has a particle size of 3-10 nm, a specific surface area of 200 m ² /g, and the nano-zirconia powder includes zirconia with a tetragonal crystal structure, and a tetragonal crystal structure. The proportion of zirconia accounts for about 75% of the powder.

"Example 3"

Weigh 1.47kg of zirconium oxychloride and 160g of yttrium chloride and dissolve in 8kg of water to obtain mixed solution A; 460g of sodium hydroxide is dissolved in 6kg of water to obtain sodium hydroxide solution B; solution A and solution B are fully stirred under stirring After mixing, a precipitation was formed, and the precipitate was washed and filtered for several times to obtain a precursor C; water and 337g propionic acid were added to the precursor C (the amount of propionic acid was 90% of the sum of the amount of zirconium element and stable element material. %), control the total volume at 8L, and stir to make slurry; put the obtained slurry into a 10L reaction kettle, and conduct hydrothermal reaction at 220 ° C for 3h; after the reaction is completed, the reaction solution is directly dried to obtain nano-zirconia powder.

The obtained nano-zirconia powder has a particle size of 3-10 nm, a specific surface area of 210 m ² /g, and the nano-zirconia powder includes zirconia with a tetragonal crystal structure, and a tetragonal crystal structure of zirconia. The proportion of zirconia accounts for about 83% of the powder.

"Example 4"

To the reaction solution after the hydrothermal reaction in Example 1, butanone (MEK) solvent was added to carry out rotary evaporation treatment, and then MEK was added after concentrating to remove water, and the MEK dispersion of zirconia was obtained after repeated dilution and concentration. Then, add modifier triphenyl phosphate (addition amount is 10wt% of zirconium content) for modification, and then add oily dispersing aid (addition amount is 5wt%) to obtain nano zirconia organic MEK type dispersion.

In the nano-zirconia organic MEK type dispersion, when the concentration of nano-zirconia is 40wt%, the refractive index is 1.458, when the concentration is 60%, the refractive index is 1.516, the concentration is 70wt%, and the refractive index is 1.554.

"Example 5"

The method for preparing nano-zirconia organic solvent-based dispersion liquid is the same as that in Example 4, the difference is that the reaction liquid after the hydrothermal reaction in Example 2 is adopted, and the amount of the modifier added is 10% of the zirconium content. % to obtain a nano-zirconia organic MEK-type dispersion.

In the nano-zirconia organic MEK type dispersion, when the concentration of nano-zirconia is 40wt%, the refractive index is 1.455, when the concentration is 60wt%, the refractive index is 1.511, the concentration is 70wt%, and the refractive index is 1.549.

"Example 6"

The method for preparing the nano-zirconia organic solvent-based dispersion liquid is the same as that in Example 4, except that the reaction liquid after the hydrothermal reaction in Example 3 is used, and the amount of the modifier added is 15wt of the zirconium content. % to obtain a nano-zirconia organic MEK-type dispersion.

In the organic MEK type dispersion of nano-zirconia, when the concentration of nano-zirconia is 40wt%, the refractive index is 1.439, when the concentration is 60wt%, the refractive index is 1.492, the concentration is 70wt%, and the refractive index is 1.545.

"Example 7"

Benzyl acrylate (added according to the concentration of zirconia in the obtained monomer dispersion is 80wt%) is added to the nano-zirconia organic MEK type dispersion prepared in Example 4, and the mixed solution is subjected to vacuum distillation to remove organic A solvent is used to obtain a nano-zirconia dispersion liquid with photocurable benzyl acrylate; the content of the nano-zirconia in the dispersion liquid is 80 wt %, and the refractive index thereof is 1.649.

"Example 8"

Benzyl acrylate (added according to the concentration of zirconia in the obtained monomer dispersion is 60wt%) is added to the nano-zirconia organic MEK type dispersion prepared in Example 5, and the mixed solution is subjected to vacuum distillation to remove organic A solvent is used to obtain a nano-zirconia dispersion liquid with photocurable benzyl acrylate; the content of the nano-zirconia in the dispersion liquid is 60wt%, and its refractive index is 1.636.

"Example 9"

Benzyl acrylate (added according to the concentration of zirconia in the obtained monomer dispersion is 50wt%) was added to the nano-zirconia organic MEK type dispersion prepared in Example 6, and the mixed solution was subjected to vacuum distillation to remove organic A solvent is used to obtain a nano-zirconia dispersion liquid with a photocurable resin; the content of the nano-zirconia in the dispersion liquid is 50 wt %, and the refractive index thereof is 1.611.

"Comparative Example 1"

Weigh 1.47kg of zirconium oxychloride and 138g of yttrium chloride and dissolve in 8kg of water to obtain its mixed solution A; 421g of sodium hydroxide is dissolved in 6kg of water to obtain sodium hydroxide solution B; The solution A and the solution B are fully mixed under stirring to form a precipitate, and the precipitate is washed and filtered for several times to obtain a precursor C; water is added to the precursor C and stirred to prepare a slurry; the above-mentioned obtained slurry is put into In a 10L reaction kettle, add 270g of acetic acid, control the total volume to 8L, and conduct a hydrothermal reaction at 200°C for 3h; after the reaction is completed, the reaction solution is directly dried to obtain nano-zirconia powder.

As shown in FIG. 4 , the obtained nano-zirconia powder has a particle size of about 30 nm and a specific surface area of 180 m ² /g, and the nano-zirconia powder includes zirconia with a tetragonal crystal structure.

"Comparative Example 2"

Weigh 1.47kg of zirconium oxychloride and 138g of yttrium chloride and dissolve in 8kg of water to obtain mixed solution A; 421g of sodium hydroxide is dissolved in 6kg of water to obtain sodium hydroxide solution B; solution A and solution B are fully stirred under stirring After mixing, a precipitate was formed, and the precipitate was washed and filtered for several times to obtain a precursor C; water and 270 g of acetic acid were added to the precursor C, and the total volume was controlled to be 8 L, and stirred to prepare a slurry; the above-mentioned obtained slurry was put into In a 10L reaction kettle, the hydrothermal reaction is carried out at 170° C. for 3 hours; after the reaction is completed, the reaction solution is directly dried to obtain nano-zirconia powder.

The obtained nano-zirconia powder had an average particle size of 30 nm and a specific surface area of 177 m ² /g, and the nano-zirconia powder was zirconia with a monoclinic phase grain structure.

"Comparative Example 3"

The method for preparing the organic solution type dispersion of nano-zirconia is the same as that in Example 4, the difference is that the solution after the hydrothermal reaction in Comparative Example 1 is used.

In the nano-zirconia organic MEK type dispersion, when the concentration of nano-zirconia is 40wt%, the refractive index is 1.445, when the concentration is 60wt%, the refractive index is 1.491, the concentration is 70wt%, and the refractive index is 1.530.

"Comparative Example 4"

The method for preparing the butanone dispersion of nano-zirconia is the same as that in Example 4, except that the solution after the hydrothermal reaction in Comparative Example 2 is used.

In the organic MEK type dispersion of nano-zirconia, when the concentration of nano-zirconia is 40wt%, the refractive index is 1.439, when the concentration is 60%, the refractive index is 1.480, the concentration is 70wt%, and the refractive index is 1.532.

"Comparative Example 5"

The method for preparing the organic solution-type dispersion of nano-zirconia is the same as that in Example 4, except that no modifier is added.

In the organic MEK type dispersion of nano-zirconia, when the concentration of nano-zirconia is 40 wt %, the refractive index is 1.416, but a dispersion with a concentration of 70 wt % cannot be obtained.

"Comparative Example 6"

The method for preparing the organic solution-type dispersion of nano-zirconia is the same as that in Example 4, except that no oily dispersing aid is added.

In the organic MEK type dispersion of nano-zirconia, when the concentration of nano-zirconia is 40 wt %, the refractive index is 1.411, but a dispersion with a concentration of 70 wt % cannot be obtained.

It can be seen from the above that under the condition that the concentration of nano-zirconia is 70wt%, the refractive index of Example 4-6 is 1.545~1.554, and the refractive index of Comparative Example 3-4 is 1.530~1.532, the difference is 0.013~0.024; Under the condition that the concentration of zirconia is 60wt%, the refractive index of Example 4-6 is 1.492~1.516, the refractive index of Comparative Example 3-4 is 1.480~1.491, and the highest difference is 0.036; the concentration of nano-zirconia is 40wt%. Below, the refractive index of Example 4-6 is 1.439~1.458, Comparative Example 3- The refractive index of 4 is 1.439~1.445, with a maximum difference of 0.013. This is because the particle size of the zirconia in the dispersion liquid in the comparative example is relatively large (Comparative Examples 3 and 4), and the crystal form is a monoclinic phase (Comparative Example 4), so that the prepared dispersion liquid has a relatively low refractive index. Although the refractive index is not much different from the numerical point of view, it is very different from the perspective of the optical properties of the refractive index of the dispersion liquid. Its light transmittance is 89% and 93%, and this is the difference between A-level screen and B-level screen. In addition, when preparing the organic solvent-based dispersion, it can be seen from Comparative Example 5 and Comparative Example 6 that when no oil-based dispersion aid or modifier is used, the content of nano-zirconia in the dispersion can only reach 40wt% at most, It was not possible to obtain a dispersion at a concentration of 70 wt %, let alone a high refractive index at 70 wt %.

Claims (17)

A nano-zirconia powder is characterized in that: the particle size of the nano-zirconia powder is 3-10 nm, the specific surface area is 200-240 m ² /g, and the nano-zirconia powder comprises tetragonal phase crystals Zirconium oxide with zirconia structure, and the proportion of zirconia with tetragonal crystal structure accounts for 60-95% of the powder; the nano zirconia powder system is prepared by the following steps: dissolving zirconium salt and stable element salt together In water, solution A is obtained; alkali is dissolved in water to obtain solution B; solution A and solution B are fully mixed under stirring to form a precipitate, wherein the mass of the precipitate accounts for 1-40% of the mass of the total mixed solution After the precipitate is washed and filtered for many times, the precursor C is obtained; in the precursor C, water and an organic acid or its salt are added to make a slurry, and the total solid content in the obtained slurry is 6-20wt%; the above-mentioned The obtained slurry is put into a reaction kettle with a filling amount of 60-90%, hydrothermally reacted at 180°C-220°C for 1-12 hours, and a reaction solution is obtained after the reaction; the reaction solution is directly dried or concentrated, washed and then dried to obtain nanometers. Zirconia powder. The nano-zirconia powder according to claim 1, wherein the added zirconium salt is a water-soluble zirconium salt selected from the group consisting of basic carbonate, carbonate, nitrate, acetate, chloride and oxychloride. at least one; the added stabilizing element salt is a chloride or nitrate of a stabilizing element, wherein the stabilizing element is selected from at least one of aluminum, magnesium, titanium and rare earth elements; the base is selected from ammonia, At least one of sodium hydroxide, potassium hydroxide and lithium hydroxide. The nano-zirconia powder as claimed in claim 2, wherein the added zirconium salt concentration

2mol/L, the molar concentration ratio of the added stability element and the zirconium element is 2/98~30/70, and the added concentration of the alkali is

8mol/L. The nano-zirconia powder according to claim 1, wherein the organic acid is at least one selected from monocarboxylic acid, polycarboxylic acid and hydroxycarboxylic acid, wherein the monocarboxylic acid is selected from formic acid, At least one of acetic acid, propionic acid and butyric acid, the polycarboxylic acid is at least one selected from oxalic acid, malonic acid, succinic acid, and phthalic acid, and the hydroxycarboxylic acid is selected from lactic acid, malic acid , at least one of tartaric acid and citric acid; the salt of the organic acid is its alkali metal salt, selected from at least one of potassium salt and sodium salt. The nano-zirconia powder according to claim 4, wherein the molar concentration of the added organic acid or its salt is 10-100% of the sum of the molar concentration of zirconium element and stabilizing element. The nano-zirconia powder according to claim 1, wherein when the boiling point of the organic acid added is <150°C, the reaction solution is directly dried to obtain the nano-zirconia powder; when the boiling point of the organic acid added is > At 150°C, the reaction solution is concentrated and washed for several times and then dried to obtain nano-zirconia powder. The nano-zirconia powder according to claim 6, wherein the drying method is any one selected from vacuum low-temperature drying, drying and spraying, and the concentrated washing method is selected from ultrafiltration, rotary evaporation and ceramics Either of the membrane concentration washes. A dispersion liquid comprising the nano-zirconia powder according to claim 1, characterized in that: the dispersion liquid is an organic solvent type dispersion liquid, and the content of the nano-zirconia in the dispersion liquid is 40-70wt% , its refractive index is 1.400-1.554. The dispersion liquid according to claim 8, characterized in that: when the content of the nano-zirconia contained in the dispersion liquid is 70 wt %, the refractive index of the dispersion liquid is not lower than 1.554. The dispersion liquid according to claim 8, wherein the dispersion liquid is obtained by replacing the dispersion medium water in the reaction liquid obtained in the preparation process of the preparation method according to claim 2 with an organic solvent, wherein the organic solvent The solvent is selected from at least one of alcohols, esters, aromatic hydrocarbons, ethers and amide organic solvents. The dispersion liquid according to claim 8, wherein a modifier is added to the dispersion liquid, and the addition amount of the modifier is 1-20wt% of the content of the nano-zirconia. The dispersion liquid of claim 11, wherein the modifier is at least one selected from the group consisting of silane coupling agents, titanate coupling agents, metal complexes, aromatic or highly conjugated chemical substances. The dispersion liquid according to claim 8, wherein an oil-based dispersing aid is added to the dispersion liquid, and the addition amount of the oil-based dispersing aid is 1-20 wt % of the content of the nano-zirconia. A kind of nano-zirconia dispersion liquid with photocurable resin, characterized in that: after the photocurable resin is added to the dispersion liquid according to any one of claims 8 to 13, the dispersion liquid is prepared by reducing It is obtained after removing the organic solvent by pressure distillation; the content of the nano-zirconia in the dispersion liquid is 50-80 wt %, and the refractive index thereof is 1.60-1.70. The nano-zirconia dispersion liquid with photocurable resin according to claim 14, wherein the addition amount of the photocurable resin is 20-50% of the total mass of the zirconia and the photocurable resin. An optical film, characterized in that: it is prepared by using the dispersion liquid as described in any one of claims 8 to 13, or using the nano-zirconia dispersion liquid with photocurable resin as described in claim 14 or 15. of. A nano-zirconia powder as claimed in claim 1, or a dispersion as claimed in any one of claims 8 to 13, or a nano-oxide with photocurable resin as claimed in claim 14 or 15 Application of zirconium dispersions in the preparation of optical films.

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