Nanometer titanium oxide dispersion liquid, its preparation method and application

Abstract

The application provides a nano titanium oxide dispersion liquid, which comprises nano titanium oxide, a double electric layer regulator and an anti-settling agent; the double electric layer regulator has a structure of D-X; wherein the D is an electron-donating group, and the electron-donating group is selected from any one or a combination of at least two of substituted or unsubstituted amino, substituted or unsubstituted alkylthio, and substituted or unsubstituted alkoxy; and the X is selected from any one or a combination of at least two of substituted or unsubstituted carboxyl, substituted or unsubstituted hydroxyl, and substituted or unsubstituted siloxy. The double electric layer regulator containing an electron-donating group is introduced to the surface of the titanium oxide, the stability of the titanium oxide dispersion liquid is enhanced by the double electric layer charge repulsion effect, and meanwhile, the anti-settling agent component is added to synergize with the double electric layer regulator, so that the stability of the dispersion liquid system is further enhanced.

Description

Technical Field

[0001] This invention relates to the field of optical material preparation technology, and in particular to a nano-titanium oxide dispersion, its preparation method, and its application. Background Technology

[0002] In recent years, solvent-based titanium dioxide dispersions with high refractive index properties, obtained by combining titanium dioxide microparticle dispersions with organic solvents, have found excellent applications in the optical field. For example, high-refractive-index nanogratings can be prepared using titanium dioxide solvent-based dispersions and used in AR diffraction waveguides, offering advantages such as high brightness and wide field of view.

[0003] Previously, as described above, titanium dioxide microparticle dispersions used water as the dispersion medium. In many optical material applications, such as the preparation of optical thin films, water dispersions are usually mixed with resin components. However, since water dispersions are particularly difficult to knead with non-water-soluble resin components, there has been a strong demand in recent years for dispersions with organic solvents as the dispersion medium.

[0004] Although some organic solvent-based dispersions have been successfully prepared, most of them suffer from poor system stability and severe particle aggregation, which greatly reduces the high refractive index characteristics of titanium oxide dispersions. In the preparation of UV adhesives, phenomena such as titanium oxide particle sedimentation and precipitation of small titanium oxide particles even occur, which seriously hinder downstream applications.

[0005] CN116355286A discloses an oleic acid-modified titanium dioxide organic transparent dispersion, its preparation method, and its application. The oleic acid-modified titanium dioxide organic transparent dispersion comprises oleic acid-modified titanium dioxide, which improves its compatibility with resins; adding it to binders can increase the refractive index of the binder and improve the optical properties of the cured product. This invention requires reacting tetrabutyl titanate and oleic acid first in a high-pressure reactor, followed by a high-temperature grafting reaction with octadecene, oleic acid, and oleylamine to prepare oleic acid-modified titanium dioxide. The preparation process is complex and requires stringent conditions. Furthermore, the electron-donating group of oleic acid only contains unsaturated carbon-carbon double bonds, limiting its ability to inhibit particle aggregation.

[0006] CN116253928A discloses a nano-titanium dioxide dispersion, its preparation method, and its application, comprising the following steps: drying and grinding titanium dioxide, then heat-treating it in an inert atmosphere, cooling it to room temperature, adding it to a solvent, and ultrasonically treating it to form a stable nano-titanium dioxide dispersion. This method only exposes the hydrophilic and lipophilic groups of titanium dioxide after high-temperature heat treatment, thus preparing the nano-titanium dioxide dispersion. However, it suffers from poor system stability and the presence of some particle agglomeration, significantly diminishing the high refractive index characteristics of the titanium dioxide dispersion.

[0007] Therefore, it is of great significance to develop titanium dioxide microparticles and their dispersions that are simple to process, have good dispersibility, and high stability.

[0008] In view of this, the present invention is hereby proposed. Summary of the Invention

[0009] One objective of this invention is to provide a nano-titanium oxide dispersion. The nano-titanium oxide dispersion comprises nano-titanium oxide, an electric double layer modifier, and an anti-settling agent in a mass ratio of (1–8):(0.1–3):(0.1–0.6); the electric double layer modifier has a DX structure. This invention provides nano-titanium oxide treated with an electric double layer modifier and prepares it into a solvent-based dispersion. The dispersion exhibits good dispersibility and high stability, and can significantly improve the performance of coatings or films in subsequent applications such as the preparation of optical adhesives or films.

[0010] A second objective of this invention is to provide a method for preparing a nano-titanium oxide dispersion. The preparation method includes the following steps: dispersing nano-titanium oxide in a solvent, and then treating the dispersion system with an electric double layer regulator and an anti-settling agent to obtain the nano-titanium oxide dispersion. This invention introduces an electric double layer regulator containing electron-donating groups onto the surface of titanium oxide, utilizing the charge repulsion effect of the electric double layer to enhance the stability of the titanium oxide dispersion; the addition of an anti-settling agent synergistically enhances the stability of the dispersion system.

[0011] The third objective of this invention is to provide an application of the aforementioned nano-titanium oxide dispersion in the preparation of optical materials.

[0012] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0013] In a first aspect, the present invention provides a nano-titanium oxide dispersion, wherein the nano-titanium oxide dispersion comprises nano-titanium oxide, an electric double layer modifier, and an anti-settling agent in a mass ratio of (1-8):(0.1-3):(0.1-0.6);

[0014] The structure of the double-layer modifier is DX;

[0015] Wherein, D is an electron-donating group, which is selected from any one or a combination of at least two of substituted or unsubstituted amino groups, substituted or unsubstituted alkylthio groups, and substituted or unsubstituted alkoxy groups;

[0016] Wherein, X is selected from any one or a combination of at least two of substituted or unsubstituted carboxyl groups, substituted or unsubstituted hydroxyl groups, and substituted or unsubstituted siloxy groups.

[0017] According to the DLVO double layer theory, when two charged titanium oxide particles approach each other, the double layers around the particles overlap and deform, generating repulsive forces between the particles. At the same time, there is also a van der Waals attraction between the two particles. When the repulsive force between the particles is greater than the van der Waals attraction between them, the stability of the particles is greatly improved, which is macroscopically manifested as the excellent dispersion stability of the titanium oxide dispersion.

[0018] Based on the above, this invention introduces a double-layer modifier containing specific electron-donating groups into titanium oxide microparticles to increase the double-layer thickness around the microparticles, thereby increasing the repulsive force between the microparticles and improving the stability of the titanium oxide dispersion. Furthermore, a certain amount of anti-settling agent is added to the system. Utilizing the synergistic effect of both, the stability of the titanium oxide solvent-based dispersion can be improved, significantly enhancing the performance of coatings or films in subsequent applications such as the preparation of optical adhesives or films.

[0019] In this invention, the mass ratio of the nano-titanium oxide, the double-layer modifier, and the anti-settling agent is (1-8):(0.1-3):(0.1-0.6).

[0020] Among them, "1 to 8" can be, for example, 1, 2, 3, 4, 5, 6, 7, 8, etc.;

[0021] Among them, "0.1~3" can be, for example, 0.1, 0.5, 1, 1.5, 2, 2.5, 3, etc.;

[0022] Among them, "0.1~0.6" can be, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, etc.

[0023] In this invention, the content of double-layer modifier and anti-settling agent should be controlled within the above-mentioned reasonable range. If the content is too low, the expected modification effect will not be achieved, and if the content is too high, the effect will be counterproductive, which will also lead to an increase in the particle aggregation rate of the dispersion and cause unnecessary economic losses.

[0024] Preferably, the electron-donating group is selected from any one or a combination of at least two of the following: C1-C12 (e.g., C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12) substituted or unsubstituted alkylamino groups, C1-C12 (e.g., C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12) substituted or unsubstituted alkylthio groups, and C1-C12 (e.g., C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12) substituted or unsubstituted alkoxy groups.

[0025] Preferably, the double-layer modifier is selected from any one of the following structures:

[0026]

[0027] R1, R2, and R3 are each independently selected from C1 to C12 straight-chain or branched alkyl groups, preferably C1 to C6 straight-chain or branched alkyl groups.

[0028] Preferably, X is selected from any one or a combination of at least two of the following: C1-C12 (e.g., C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12) substituted or unsubstituted carboxyl groups; C1-C12 (e.g., C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12) substituted or unsubstituted hydroxyl groups; and C1-C12 (e.g., C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12) substituted or unsubstituted siloxy groups.

[0029] Preferably, X is selected from any one of the following groups, wherein, Representative substituent junctions:

[0030]

[0031] R1, R4, R5, and R6 are each independently selected from C1 to C12 straight-chain or branched alkyl groups, preferably C1 to C6 straight-chain or branched alkyl groups.

[0032] Preferably, the double-layer modifier is selected from any one or a combination of at least two of dimethylglycine, ethyl thioacetic acid, 2-isopropylmercaptoethanol, 2-ethylaminoethanol, or 3-methoxypropyltrimethoxysilane.

[0033] In this invention, by adding the double-layer modifier with the preferred structure described above, the double-layer modifier increases the lipophilicity of the titanium dioxide particles on the one hand, and on the other hand, the electron-donating groups it carries can increase the thickness of the double layer around the particles, thereby inhibiting particle aggregation. The prepared titanium dioxide solvent-based dispersion has an adjustable concentration and high stability, with a particle aggregation rate of 0.2–3.7.

[0034] Preferably, the anti-settling agent is selected from any one or a combination of at least two of the following: carboxylic acid derivatives, sulfonate derivatives, sulfate ester derivatives, phosphate ester derivatives, amide ammonium salts, polyacrylates, or amide polyester ammonium salts.

[0035] Preferably, the anti-settling agent is selected from any one or a combination of at least two of RH6075, CR6430W, CR6421W or CR6422W.

[0036] In this invention, by adding the anti-settling agent with the above-mentioned preferred structure, the double-layer regulator can better exert a synergistic effect, thereby further enhancing the stability of the dispersion system.

[0037] Preferably, the nano-titanium oxide is nano-titanium oxide that has undergone acid pretreatment.

[0038] Preferably, the particle size of the nano-titanium oxide is 1 to 50 nm, for example, it can be 1 nm, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, etc.

[0039] Preferably, the acid is a combination of hydrochloric acid and acetic acid.

[0040] Preferably, the mass ratio of hydrochloric acid to acetic acid is (0-5):(0-5), for example, it can be 0:1, 1:0, 1:1, 1:2, 1:3, 1:4, 1:5, 5:1, 4:1, 3:1, 2:1, etc.

[0041] Preferably, the solid content of the nano-titanium oxide in the nano-titanium oxide dispersion is 10-80 wt%, for example, it can be 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, etc.

[0042] Preferably, the amount of the double-layer modifier added is 1 to 30 wt% of the nano-titanium oxide content, for example, it can be 1 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, etc.

[0043] Preferably, the amount of anti-settling agent added is 1 to 6 wt% of the nano-titanium oxide content, for example, it can be 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, etc.

[0044] Preferably, the particle aggregation rate of the nano-titanium oxide dispersion is 0.2 to 2.8, for example, it can be 0.2, 0.4, 0.6, 0.8, 1, 1.2, 1.4, 1.6, 1.8, 2, 2.2, 2.4, 2.6, 2.8, etc.

[0045] Preferably, the solvent for the nano-titanium oxide dispersion is an organic solvent.

[0046] Preferably, the organic solvent is selected from any one or a combination of at least two of alcohols, ketones, esters, ethers, aromatic hydrocarbons, halogenated hydrocarbons or cycloalkanes, more preferably from any one or a combination of at least two of diols, esters or ethers, and more preferably from alcohol-ether-ester solvents.

[0047] Preferably, the alcohol ether ester solvent is selected from any one or a combination of at least two of ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, diethylene glycol ethyl ether acetate, diethylene glycol butyl ether acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate or propylene glycol butyl ether acetate, preferably propylene glycol methyl ether acetate.

[0048] In a second aspect, the present invention provides a method for preparing the nano-titanium oxide dispersion according to the first aspect, the preparation method comprising the following steps:

[0049] Nano-titanium oxide is dispersed in a solvent, and then the dispersion system is treated with an electric double layer regulator and an anti-settling agent to obtain the nano-titanium oxide dispersion.

[0050] The preparation method provided by this invention is simple, low-cost, and does not require complex equipment. It can produce highly stable solvent-based titanium dioxide dispersions.

[0051] In this invention, the nano-titanium oxide needs to undergo acid pretreatment, which specifically includes the following steps:

[0052] Nano-titanium oxide powder, organic solvent and acid are mixed, heated and stirred to obtain a suspension;

[0053] The suspension was centrifuged, the supernatant was separated, the wet cake was collected and washed to obtain nano-titanium oxide after acid pretreatment.

[0054] In this invention, the powder treatment of nano-titanium oxide can, on the one hand, alter the electrical charge and charge on the surface of the titanium oxide particles, which is beneficial for regulating the electric double layer structure around the particles and increasing the repulsive force between particles to improve the stability of the dispersion. On the other hand, it can significantly reduce the residual groups such as solvents and impurities coated or grafted on the surface of titanium oxide particles, thereby greatly increasing the number of active sites on the particle surface, which is conducive to the interaction between the electric double layer regulator and the titanium oxide particles.

[0055] Preferably, the mass ratio of the nano-titanium oxide powder to the organic solvent is 1:(1-6), for example, it can be 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, etc.

[0056] Preferably, after the acid is added, the pH of the system is 0.8 to 1.2, for example, it can be 0.8, 0.9, 1.0, 1.1, 1.2, etc.

[0057] Preferably, the heating and stirring temperature is 50-70°C, for example, 50°C, 55°C, 60°C, 65°C, 70°C, etc., and the heating and stirring time is 8-16 hours, for example, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, etc.

[0058] Preferably, the centrifugation speed is 8000-12000 rpm, for example, 8000 rpm, 9000 rpm, 10000 rpm, 11000 rpm, 12000 rpm, etc., and the time is 5-30 min, for example, 5 min, 6 min, 8 min, 10 min, 15 min, 20 min, 25 min, 30 min, etc.

[0059] Preferably, the washing is performed more than twice, for example, twice, four times, six times, eight times, ten times, etc.

[0060] Preferably, the solvent used for washing is propylene glycol methyl ether.

[0061] As a preferred embodiment of the present invention, the nano-titanium oxide needs to undergo acid pretreatment, which specifically includes the following steps:

[0062] Titanium oxide powder was added to an organic solvent at a mass ratio of 1:(1-6), and a mixed acid solution of hydrochloric acid and acetic acid was added to adjust the pH of the solution to 0.8-1.2. The solution was then stirred at 50-70°C for 8-16 hours to obtain a white suspension.

[0063] The above white suspension was transferred to a centrifuge bottle and centrifuged at 8000-12000 rpm for 5-30 min. The supernatant was separated to obtain a wet cake, which was then washed more than twice to obtain nano-titanium oxide after acid pretreatment.

[0064] Preferably, the temperature at which the dispersion system is treated with the double-layer regulator and the anti-settling agent is 50 to 200°C, for example, 50°C, 60°C, 80°C, 100°C, 120°C, 140°C, 160°C, 180°C, 200°C, etc.

[0065] Preferably, the processing time is 10 min to 3 h, for example, it can be 10 min, 20 min, 30 min, 35 min, 40 min, 45 min, 50 min, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, etc.

[0066] Preferably, the treatment is carried out under stirring, and the stirring speed is 100 to 1000 rpm, for example, 100 rpm, 200 rpm, 300 rpm, 400 rpm, 500 rpm, 600 rpm, 700 rpm, 800 rpm, 900 rpm, 1000 rpm, etc.

[0067] In a second aspect, the present invention provides an application of the nano-titanium oxide dispersion according to the first aspect in the preparation of optical materials.

[0068] Compared with the prior art, the present invention has the following beneficial effects:

[0069] (1) In this invention, an electric double layer regulator containing electron-donating groups is introduced onto the surface of titanium dioxide to enhance the stability of the titanium dioxide dispersion by utilizing the charge repulsion effect of the electric double layer; at the same time, an anti-settling agent is added to work synergistically with the electric double layer regulator to further enhance the stability of the dispersion system. The particle aggregation rate of the nano-titanium dioxide dispersion prepared is 0.2-3.7.

[0070] (2) The preparation method given by the present invention is simple and low in cost. No complex process equipment is required in the preparation process, and a highly stable solvent-based titanium dioxide dispersion can be prepared. Detailed Implementation

[0071] Unless otherwise defined herein, the scientific and technical terms used in conjunction with this invention shall have the meanings commonly understood by one of ordinary skill in the art. The meaning and scope of terms shall be clear; however, in any case of potential ambiguity, the definitions provided herein shall prevail over any dictionary or foreign definitions. In this application, unless otherwise stated, the use of "or" means "and / or". Furthermore, the use of the term "comprising" and other forms is non-limiting.

[0072] It should be noted that specific details are set forth in the following description to provide a full understanding of the invention. However, the invention can be practiced in many ways other than those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0073] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0074] The present invention will be further illustrated by the following examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or purchased directly from the market.

[0075] Preparation Example 1

[0076] This preparation example provides an acid-pretreated nano-titanium oxide, which is prepared by the following steps:

[0077] Titanium oxide powder with an average particle size of 18 nm was added to propylene glycol methyl ether acetate at a mass ratio of 1:3. A mixed acid solution of hydrochloric acid (37% by mass) and acetic acid (99% by mass) at a mass ratio of 1:1 was added to adjust the pH of the dispersion to 1.0. The mixture was stirred at 60°C for 12 h to obtain a white suspension. The white suspension was transferred to a centrifuge bottle and centrifuged at 10,000 rpm for 15 min. The supernatant was separated to obtain a wet cake, which was then washed three times with propylene glycol methyl ether solvent.

[0078] Preparation Example 2

[0079] This preparation example provides an acid-pretreated nano-titanium oxide, which is prepared by the following steps:

[0080] Titanium oxide powder with an average particle size of 5 nm was added to propylene glycol methyl ether acetate at a mass ratio of 1:4. A mixed acid solution of hydrochloric acid (37% by mass) and acetic acid (99% by mass) at a mass ratio of 1:2 was added to adjust the pH of the dispersion to 0.8. The mixture was stirred at 55°C for 14 h to obtain a white suspension. The white suspension was transferred to a centrifuge bottle and centrifuged at 8000 rpm for 25 min. The supernatant was separated to obtain a wet cake, which was then washed twice with propylene glycol methyl ether solvent.

[0081] Preparation Example 3

[0082] This preparation example provides an acid-pretreated nano-titanium oxide, which is prepared by the following steps:

[0083] Titanium oxide powder with an average particle size of 13 nm was added to propylene glycol methyl ether acetate at a mass ratio of 1:2. A mixed acid solution of hydrochloric acid (37%) and acetic acid (99%) at a mass ratio of 2:1 was added to adjust the pH of the dispersion to 1.2. The mixture was stirred at 55°C for 14 h to obtain a white suspension. The white suspension was transferred to a centrifuge bottle and centrifuged at 12000 rpm for 10 min. The supernatant was separated to obtain a wet cake, which was then washed four times with propylene glycol methyl ether solvent.

[0084] Preparation Example 4

[0085] This preparation example provides an acid-pretreated nano-titanium oxide, which is prepared by the following steps:

[0086] Titanium oxide powder with an average particle size of 30 nm was added to propylene glycol methyl ether acetate at a mass ratio of 1:3. Hydrochloric acid (37%) solution was added to adjust the pH of the dispersion to 1.0. The mixture was stirred at 60°C for 16 h to obtain a white suspension. The white suspension was transferred to a centrifuge bottle and centrifuged at 10,000 rpm for 15 min. The supernatant was separated to obtain a wet cake, which was then washed three times with propylene glycol methyl ether solvent.

[0087] Preparation Example 5

[0088] This preparation example provides an acid-pretreated nano-titanium oxide, which is prepared by the following steps:

[0089] Titanium oxide powder with an average particle size of 50 nm was added to propylene glycol methyl ether acetate at a mass ratio of 1:3, and the pH of the dispersion was adjusted to 1.0 with 99% acetic acid solution. The mixture was stirred at 60°C for 16 h to obtain a white suspension. The white suspension was transferred to a centrifuge bottle and centrifuged at 10,000 rpm for 15 min. The supernatant was separated to obtain a wet cake, which was then washed three times with propylene glycol methyl ether solvent.

[0090] Example 1

[0091] This embodiment provides a nano-titanium oxide dispersion, which is prepared by the following steps:

[0092] The pretreated wet cake obtained in Preparation Example 1 was added to propylene glycol methyl ether acetate solvent at a mass ratio of 1:2 and stirred and dispersed continuously at 500 rpm for 30 min. Then, dimethylglycine (1% of the titanium dioxide content) and RH6075 (1% of the titanium dioxide content) were added to the above system, and the surface was treated at 120°C and 500 rpm for 60 min to obtain the treated nano-titanium dioxide PGMEA type dispersion.

[0093] Example 2

[0094] This embodiment provides a nano-titanium oxide dispersion, which is prepared by the following steps:

[0095] The pretreated wet cake obtained in Preparation Example 1 was added to propylene glycol methyl ether acetate solvent at a mass ratio of 1:2 and stirred and dispersed continuously at 500 rpm for 30 min. Then, dimethylglycine (30% of the titanium dioxide content) and RH6075 (6% of the titanium dioxide content) were added to the above system, and the surface was treated at 120°C and 500 rpm for 60 min to obtain the treated nano-titanium dioxide PGMEA type dispersion.

[0096] Example 3

[0097] This embodiment provides a nano-titanium oxide dispersion, which is prepared by the following steps:

[0098] The pretreated wet cake obtained in Preparation Example 1 was added to propylene glycol methyl ether acetate solvent at a mass ratio of 1:2 and stirred and dispersed continuously at 500 rpm for 30 min. Then, dimethylglycine (15% of the titanium dioxide content) and RH6075 (3% of the titanium dioxide content) were added to the above system, and the surface was treated at 120°C and 500 rpm for 60 min to obtain the treated nano-titanium dioxide PGMEA type dispersion.

[0099] Example 4

[0100] This embodiment provides a nano-titanium oxide dispersion, which is prepared by the following steps:

[0101] The pretreated wet cake obtained in Preparation Example 1 was added to propylene glycol methyl ether acetate solvent at a mass ratio of 1:2 and stirred and dispersed continuously at 500 rpm for 30 min. Then, dimethylglycine (15% of the titanium dioxide content) and CR6430W (3% of the titanium dioxide content) were added to the above system, and the surface was treated at 120°C and 500 rpm for 60 min to obtain the treated nano-titanium dioxide PGMEA type dispersion.

[0102] Example 5

[0103] This embodiment provides a nano-titanium oxide dispersion, which is prepared by the following steps:

[0104] The pretreated wet cake obtained in Preparation Example 1 was added to propylene glycol methyl ether acetate solvent at a mass ratio of 1:2 and stirred and dispersed continuously at 500 rpm for 30 min. Then, dimethylglycine (15% of the titanium dioxide content) and CR6421W (3% of the titanium dioxide content) were added to the above system, and the surface was treated at 120°C and 500 rpm for 60 min to obtain the treated nano-titanium dioxide PGMEA type dispersion.

[0105] Example 6

[0106] This embodiment provides a nano-titanium oxide dispersion, which is prepared by the following steps:

[0107] The pretreated wet cake obtained in Preparation Example 1 was added to propylene glycol methyl ether acetate solvent at a mass ratio of 1:2 and stirred and dispersed continuously at 500 rpm for 30 min. Then, dimethylglycine (15% of the titanium dioxide content) and CR6422W (3% of the titanium dioxide content) were added to the above system, and the surface was treated at 120°C and 500 rpm for 60 min to obtain the treated nano-titanium dioxide PGMEA type dispersion.

[0108] Example 7

[0109] This embodiment provides a nano-titanium oxide dispersion, which is prepared by the following steps:

[0110] The pretreated wet cake obtained in Preparation Example 1 was added to propylene glycol methyl ether acetate solvent at a mass ratio of 1:2 and stirred and dispersed continuously at 500 rpm for 30 min. Then, ethyl thioacetic acid (15% of the titanium dioxide content) and RH6075 (3% of the titanium dioxide content) were added to the above system, and the surface was treated at 120°C and 500 rpm for 60 min to obtain the treated nano-titanium dioxide PGMEA type dispersion.

[0111] Example 8

[0112] This embodiment provides a nano-titanium oxide dispersion, which is prepared by the following steps:

[0113] The pretreated wet cake obtained in Preparation Example 1 was added to propylene glycol methyl ether acetate solvent at a mass ratio of 1:2 and stirred and dispersed continuously at 500 rpm for 30 min. Then, 2-isopropylmercaptoethanol (15% of the titanium dioxide content) and RH6075 (3% of the titanium dioxide content) were added to the above system, and the surface was treated at 120°C and 500 rpm for 60 min to obtain the treated nano-titanium dioxide PGMEA dispersion.

[0114] Example 9

[0115] This embodiment provides a nano-titanium oxide dispersion, which is prepared by the following steps:

[0116] The pretreated wet cake obtained in Preparation Example 1 was added to propylene glycol methyl ether acetate solvent at a mass ratio of 1:2 and stirred and dispersed continuously at 500 rpm for 30 min. Then, 2-ethylaminoethanol (15% of the titanium oxide content) and RH6075 (3% of the titanium oxide content) were added to the above system, and the surface was treated at 120°C and 500 rpm for 60 min to obtain the treated nano-titanium oxide PGMEA type dispersion.

[0117] Example 10

[0118] This embodiment provides a nano-titanium oxide dispersion, which is prepared by the following steps:

[0119] The pretreated wet cake obtained in Preparation Example 1 was added to propylene glycol methyl ether acetate solvent at a mass ratio of 1:2 and stirred and dispersed continuously at 500 rpm for 30 min. Then, 3-methoxypropyltrimethoxysilane (15% of the titanium oxide content) and RH6075 (3% of the titanium oxide content) were added to the above system, and the surface was treated at 120°C and 500 rpm for 60 min to obtain the treated nano-titanium oxide PGMEA type dispersion.

[0120] Example 11

[0121] This embodiment provides a nano-titanium oxide dispersion, which is prepared by the following steps:

[0122] The pretreated wet cake obtained in Preparation Example 1 was added to propylene glycol methyl ether acetate solvent at a mass ratio of 1:2 and stirred and dispersed continuously at 500 rpm for 30 min. Then, 3-methoxyacetic acid (15% of the titanium oxide content) and RH6075 (3% of the titanium oxide content) were added to the above system, and the surface was treated at 120°C and 500 rpm for 60 min to obtain the treated nano-titanium oxide PGMEA type dispersion.

[0123] Example 12

[0124] This embodiment provides a nano-titanium oxide dispersion, which is prepared by the following steps:

[0125] The pretreated wet cake obtained in Preparation Example 2 was added to propylene glycol methyl ether acetate solvent at a mass ratio of 1:2 and stirred and dispersed continuously at 100 rpm for 30 min. Then, dimethylglycine (15% of the titanium dioxide content) and RH6075 (3% of the titanium dioxide content) were added to the above system, and the surface was treated at 50°C and 100 rpm for 10 min to obtain the treated nano-titanium dioxide PGMEA type dispersion.

[0126] Example 13

[0127] This embodiment provides a nano-titanium oxide dispersion, which is prepared by the following steps:

[0128] The pretreated wet cake obtained in Preparation Example 3 was added to propylene glycol methyl ether acetate solvent at a mass ratio of 1:2 and stirred and dispersed continuously at 1000 rpm for 30 min. Then, dimethylglycine (15% of the titanium dioxide content) and RH6075 (3% of the titanium dioxide content) were added to the above system, and the surface was treated at 200°C and 1000 rpm for 180 min to obtain the treated nano-titanium dioxide PGMEA type dispersion.

[0129] Example 14

[0130] This embodiment provides a nano-titanium oxide dispersion, which is prepared by the following steps:

[0131] The pretreated wet cake obtained in Preparation Example 4 was added to propylene glycol methyl ether acetate solvent at a mass ratio of 1:2 and stirred and dispersed continuously at 800 rpm for 30 min. Then, dimethylglycine (15% of the titanium dioxide content) and RH6075 (3% of the titanium dioxide content) were added to the above system, and the surface was treated at 80°C and 800 rpm for 120 min to obtain the treated nano-titanium dioxide PGMEA type dispersion.

[0132] Example 15

[0133] This embodiment provides a nano-titanium oxide dispersion, which is prepared by the following steps:

[0134] The pretreated wet cake obtained in Preparation Example 5 was added to propylene glycol methyl ether acetate solvent at a mass ratio of 1:2 and stirred and dispersed continuously at 500 rpm for 30 min. Then, dimethylglycine (15% of the titanium dioxide content) and RH6075 (3% of the titanium dioxide content) were added to the above system, and the surface was treated at 150°C and 500 rpm for 60 min to obtain the treated nano-titanium dioxide PGMEA type dispersion.

[0135] Example 16

[0136] This embodiment provides a nano-titanium oxide dispersion, which is prepared by the following steps:

[0137] The pretreated wet cake obtained in Preparation Example 1 was added to ethylene glycol butyl ether acetate solvent at a mass ratio of 1:2 and stirred and dispersed continuously at 500 rpm for 30 min. Then, dimethylglycine (15% of the titanium dioxide content) and RH6075 (3% of the titanium dioxide content) were added to the above system, and the surface was treated at 120°C and 500 rpm for 60 min to obtain the treated nano-titanium dioxide PGMEA type dispersion.

[0138] Example 17

[0139] This embodiment provides a nano-titanium oxide dispersion, which is prepared by the following steps:

[0140] The pretreated wet cake obtained in Preparation Example 1 was added to propylene glycol at a mass ratio of 1:2 and stirred and dispersed continuously at 500 rpm for 30 min. Then, dimethylglycine (15% of the titanium dioxide content) and RH6075 (3% of the titanium dioxide content) were added to the above system, and the surface was treated at 120°C and 500 rpm for 60 min to obtain the treated nano-titanium dioxide PGMEA type dispersion.

[0141] Example 18

[0142] This embodiment provides a nano-titanium oxide dispersion, which is prepared by the following steps:

[0143] The pretreated wet cake obtained in Preparation Example 1 was added to propylene glycol methyl ether acetate solvent at a mass ratio of 1:2 and stirred and dispersed continuously at 500 rpm for 30 min. Then, dimethylglycine (15% of the titanium dioxide content) and polyethylene glycol (3% of the titanium dioxide content) were added to the above system, and the surface was treated at 120°C and 500 rpm for 60 min to obtain the treated nano-titanium dioxide PGMEA type dispersion.

[0144] Comparative Example 1

[0145] This comparative example provides a nano-titanium oxide dispersion, which is prepared by the following steps:

[0146] The pretreated wet cake obtained in Preparation Example 1 was added to propylene glycol methyl ether acetate solvent at a mass ratio of 1:2 and stirred and dispersed continuously at 500 rpm for 30 min. Then, RH6075 (3% of the titanium oxide content) was added to the above system and surface treated at 120°C at 500 rpm for 60 min to obtain the treated nano-titanium oxide PGMEA dispersion.

[0147] Comparative Example 2

[0148] This comparative example provides a nano-titanium oxide dispersion, which is prepared by the following steps:

[0149] The pretreated wet cake obtained in Preparation Example 1 was added to propylene glycol methyl ether acetate solvent at a mass ratio of 1:2 and stirred and dispersed continuously at 500 rpm for 30 min. Then, dimethylglycine (15% of the titanium dioxide content) was added to the above system and surface treated at 120°C at 500 rpm for 60 min to obtain the treated nano-titanium dioxide PGMEA type dispersion.

[0150] Comparative Example 3

[0151] This comparative example provides a nano-titanium oxide dispersion, which is prepared by the following steps:

[0152] The pretreated wet cake obtained in Preparation Example 1 was added to propylene glycol methyl ether acetate solvent at a mass ratio of 1:2 and stirred and dispersed continuously at 500 rpm for 30 min. Then, dimethylglycine (50% of the titanium dioxide content) and RH6075 (20% of the titanium dioxide content) were added to the above system, and the surface was treated at 120°C and 500 rpm for 60 min to obtain the treated nano-titanium dioxide PGMEA type dispersion.

[0153] Comparative Example 4

[0154] This comparative example provides a nano-titanium oxide dispersion, which is prepared by the following steps:

[0155] The pretreated wet cake obtained in Preparation Example 1 was added to propylene glycol methyl ether acetate solvent at a mass ratio of 1:2 and stirred and dispersed continuously at 500 rpm for 30 min. Then, n-butyric acid (15% of the titanium oxide content) and RH6075 (3% of the titanium oxide content) were added to the above system, and the surface was treated at 120°C and 500 rpm for 60 min to obtain the treated nano-titanium oxide PGMEA type dispersion.

[0156] Comparative Example 5

[0157] This comparative example provides a nano-titanium oxide dispersion, which is prepared by the following steps:

[0158] The pretreated wet cake obtained in Preparation Example 1 was added to propylene glycol methyl ether acetate solvent at a mass ratio of 1:2, and stirred and dispersed continuously at a speed of 500 rpm for 30 min. The titanium oxide particles settled, and a uniform and stable nano-titanium oxide PGMEA type dispersion was obtained.

[0159] Comparative Example 6

[0160] This comparative example provides a nano-titanium oxide dispersion, which is prepared by the following steps:

[0161] The pretreated wet cake obtained in Preparation Example 1 was added to propylene glycol methyl ether acetate solvent at a mass ratio of 1:2 and stirred and dispersed continuously at 500 rpm for 30 min. Then, RH6075 (20% of the titanium oxide content) was added to the above system and surface treated at 120°C at 500 rpm for 60 min to obtain the treated nano-titanium oxide PGMEA dispersion.

[0162] Comparative Example 7

[0163] This comparative example provides a nano-titanium oxide dispersion, which is prepared by the following steps:

[0164] The pretreated wet cake obtained in Preparation Example 1 was added to propylene glycol methyl ether acetate solvent at a mass ratio of 1:2 and stirred and dispersed continuously at 500 rpm for 30 min. Then, dimethylglycine (50% of the titanium dioxide content) was added to the above system and surface treated at 120°C at 500 rpm for 60 min to obtain the treated nano-titanium dioxide PGMEA type dispersion.

[0165] Comparative Example 8

[0166] This comparative example provides a nano-titanium oxide dispersion, which is prepared by the following steps:

[0167] Untreated nano-titanium oxide was added to propylene glycol methyl ether acetate solvent at a mass ratio of 1:2 and stirred continuously at 500 rpm for 30 min. Then, dimethylglycine (15% of the titanium oxide content) and RH6075 (3% of the titanium oxide content) were added to the above system, and the surface was treated at 120℃ at 500 rpm for 60 min to obtain the treated nano-titanium oxide PGMEA dispersion.

[0168] Test Example 1

[0169] Test samples: nano-titanium oxide dispersions provided in Examples 1-18 and comparative examples 1-8;

[0170] Test method: Particle agglomeration rate = (average secondary particle size of powder particles - average primary particle size of powder particles) / average primary particle size of powder particles;

[0171] As can be seen from the above formula for calculating the particle agglomeration rate, when the particle agglomeration rate is 0, that is, the average secondary particle size of the powder particles is the same as the average primary particle size of the powder particles, that is, the powder has not agglomerated. The larger the particle agglomeration rate value, the more serious the agglomeration of the powder particles.

[0172] In this invention, the average primary particle size of titanium oxide particles is the average particle size of particles in the pretreated titanium oxide wet cake, and the average secondary particle size of titanium oxide particles is the average particle size of particles in the titanium oxide PGMEA dispersion.

[0173] The specific test results are shown in Table 1:

[0174] Table 1

[0175]

[0176]

[0177] As shown in Table 1, the concentration of the titanium dioxide solvent-based dispersion prepared by this invention is adjustable, and it also has high stability. The particle aggregation rate of the dispersion is 0.2-3.7.

[0178] Compared with Comparative Example 4, the double-layer regulator n-butyric acid in Comparative Example 4 does not contain electron-donating groups, and its particle aggregation rate is much higher than that in the Example. This shows that the introduction of electron-donating groups can increase the repulsive force between particles and play an important role in maintaining the stability of the dispersion.

[0179] Comparative Examples 1, 2, 6, and 7 all exhibited higher particle aggregation rates than the Examples without the addition of double-layer regulators and anti-settling agents, indicating that double-layer regulators and anti-settling agents have a synergistic effect in maintaining the stability of the dispersion, and both components are indispensable.

[0180] In addition, the content of double-layer regulators and anti-settling agents has a significant impact on the stability of the dispersion and the dispersion preparation process. Their dosage should be controlled within a reasonable range; otherwise, it will not only have the opposite effect but may even directly lead to the failure of dispersion preparation. Examples 1, 2, 3 and Comparative Examples 3 and 5 fully demonstrate this point.

[0181] Meanwhile, in Examples 3-11 and 18, the particle aggregation rate of the dispersions varied greatly due to the different types of double-layer regulators and anti-settling agents. This indicates that different structures have different effects on the double layer, and therefore the stability of the dispersions is also different.

[0182] Furthermore, the pretreatment process of the particles has a significant impact on the stability of the dispersion and the dispersion preparation process, as fully demonstrated in Examples 12-15 and Comparative Example 8.

[0183] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A nano-titanium oxide dispersion, characterized in that, The nano-titanium oxide dispersion comprises nano-titanium oxide, an electric double layer regulator, and an anti-settling agent; the mass ratio of the nano-titanium oxide, the electric double layer regulator, and the anti-settling agent is (1~8):(0.1~3):(0.1~0.6). The nano-titanium oxide is nano-titanium oxide that has undergone acid pretreatment; The double-layer modifier is selected from any one of the following structures: 、 ； Wherein, R1, R2, and R3 are each independently selected from C1-C6 straight-chain or branched alkyl groups; X is selected from any one or a combination of at least two of C1-C12 substituted or unsubstituted carboxyl groups or C1-C12 substituted or unsubstituted hydroxyl groups. The anti-settling agent is selected from any one or a combination of at least two of the following: carboxylic acid derivatives, sulfonate derivatives, sulfate ester derivatives, phosphate ester derivatives, amide ammonium salts, polyacrylates, or amide polyester ammonium salts. The amount of the double-layer modifier added is 1 to 30 wt% of the nano-titanium oxide content, and the amount of the anti-settling agent added is 1 to 6 wt% of the nano-titanium oxide content.

2. The nano-titanium oxide dispersion according to claim 1, characterized in that, X is selected from any one of the following groups, wherein... Representative substituent junctions: 、 ； R1 is selected from C1-C6 straight-chain or branched alkyl groups.

3. The nano-titanium oxide dispersion according to claim 1, characterized in that, The double-layer modifier is selected from any one or a combination of at least two of dimethylglycine, ethyl thioacetic acid, 2-isopropylmercaptoethanol, or 2-ethylaminoethanol.

4. The nano-titanium oxide dispersion according to claim 1, characterized in that, The anti-settling agent is selected from any one or a combination of at least two of RH6075, CR6430W, CR6421W or CR6422W.

5. The nano-titanium oxide dispersion according to claim 1, characterized in that, The particle size of the nano-titanium oxide is 1~50 nm.

6. The nano-titanium oxide dispersion according to claim 1, characterized in that, The acid is a combination of hydrochloric acid and acetic acid.

7. The nano-titanium oxide dispersion according to claim 6, characterized in that, The mass ratio of hydrochloric acid to acetic acid is (0~5):(0~5).

8. The nano-titanium oxide dispersion according to claim 1, characterized in that, The solid content of the nano-titanium oxide in the nano-titanium oxide dispersion is 10~80 wt%.

9. The nano-titanium oxide dispersion according to claim 1, characterized in that, The particle aggregation rate of the nano-titanium oxide dispersion is 0.2~2.

8.

10. The nano-titanium oxide dispersion according to claim 1, characterized in that, The solvent for the nano-titanium oxide dispersion is an organic solvent.

11. The nano-titanium oxide dispersion according to claim 10, characterized in that, The organic solvent is selected from any one or a combination of at least two of the following solvents: alcohols, ketones, esters, ethers, aromatic hydrocarbons, halogenated hydrocarbons, or cycloalkanes.

12. The nano-titanium oxide dispersion according to claim 11, characterized in that, The organic solvent is any one or a combination of at least two of the following: glycols, esters, or ethers.

13. The nano-titanium oxide dispersion according to claim 12, characterized in that, The organic solvent is an alcohol ether ester solvent.

14. The nano-titanium oxide dispersion according to claim 13, characterized in that, The alcohol ether ester solvent is selected from any one or a combination of at least two of ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, diethylene glycol ethyl ether acetate, diethylene glycol butyl ether acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, or propylene glycol butyl ether acetate.

15. The nano-titanium oxide dispersion according to claim 14, characterized in that, The alcohol ether ester solvent is propylene glycol methyl ether acetate.

16. A method for preparing a nano-titanium oxide dispersion according to any one of claims 1 to 15, characterized in that, The preparation method includes the following steps: Nano-titanium oxide is dispersed in a solvent, and then the dispersion system is treated with an electric double layer regulator and an anti-settling agent to obtain the nano-titanium oxide dispersion.

17. The method for preparing the nano-titanium oxide dispersion according to claim 16, characterized in that, The nano-titanium oxide needs to undergo acid pretreatment, which specifically includes the following steps: Nano-titanium oxide powder, organic solvent and acid are mixed, heated and stirred to obtain a suspension; The suspension was centrifuged, the supernatant was separated, the wet cake was collected and washed to obtain nano-titanium oxide after acid pretreatment.

18. The method for preparing the nano-titanium oxide dispersion according to claim 17, characterized in that, The mass ratio of the nano-titanium oxide powder to the organic solvent is 1:(1~6).

19. The method for preparing the nano-titanium oxide dispersion according to claim 17, characterized in that, After the acid is added, the pH of the system is 0.8~1.

2.

20. The method for preparing the nano-titanium oxide dispersion according to claim 17, characterized in that, The heating and stirring temperature is 50~70℃, and the heating and stirring time is 8~16 h.

21. The method for preparing the nano-titanium oxide dispersion according to claim 17, characterized in that, The centrifugation speed is 8000~12000 rpm, and the time is 5~30 min.

22. The method for preparing the nano-titanium oxide dispersion according to claim 17, characterized in that, The washing process is performed at least twice.

23. The method for preparing the nano-titanium oxide dispersion according to claim 17, characterized in that, The solvent used for washing is propylene glycol methyl ether.

24. The method for preparing the nano-titanium oxide dispersion according to claim 16, characterized in that, The temperature at which the dispersion system is treated with double-layer regulators and anti-settling agents is 50~200℃.

25. The method for preparing the nano-titanium oxide dispersion according to claim 24, characterized in that, The processing time is 10 min to 3 h.

26. The method for preparing the nano-titanium oxide dispersion according to claim 24, characterized in that, The treatment is carried out under stirring at a speed of 100-1000 rpm.

27. The application of a nano-titanium oxide dispersion according to any one of claims 1 to 15 in the preparation of optical materials.

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