Nanoparticle dispersants, their preparation methods, and aqueous dispersions of stable nanoparticles containing these dispersants.

Abstract

This invention relates to nanoparticle dispersants, methods for preparing the same, and aqueous dispersions of stable nanoparticles containing the dispersant. Specifically, the dispersant is suitable for dispersing nanoparticles and comprises an amphiphilic polymer having an amine-containing backbone and UV-photocrosslinkable functional groups covalently bonded to the backbone, and further comprising hydrophilic polyether segments and / or hydrophobic organic segments. The aqueous dispersion comprises a photocrosslinked nanoparticle dispersant and nanoparticles.

Description

Technical Field

[0001] This invention relates to a nanoparticle dispersant and its preparation method. It also relates to a stable aqueous dispersion of nanoparticles containing the aforementioned nanoparticle dispersant and its applications in various fields. Background Technology

[0002] Nanoparticles refer to particles with a size between 1 and 100 nm, also known as ultrafine particles. The efficient dispersion of these particles plays a crucial role in the preparation of nanocomposites, especially in fields such as coatings, inks, and printing, where the dispersibility of nanoparticles within the system directly determines the product's performance. However, due to the high surface energy of nanoparticles, their van der Waals forces and Brownian motion are more intense, easily leading to aggregation and significantly negatively impacting the physical and chemical properties of the products. Therefore, finding an efficient and cost-effective method to improve the dispersibility and stability of nanoparticles is of great significance for enhancing the performance of nanocomposites.

[0003] Currently reported methods for improving the dispersibility of nanoparticles mainly focus on surface functionalization, which can be broadly categorized into two types based on different mechanisms: physical adsorption and chemical modification. Physical adsorption primarily involves coating dispersant molecules onto the nanoparticle surface through electrostatic interactions, hydrophilic-hydrophobic interactions, etc., thereby reducing the surface energy of the nanoparticles and inducing a strong steric hindrance effect, resulting in effective dispersion. However, the adsorption of dispersants on the nanoparticle surface involves an adsorption-desorption equilibrium, and desorption can lead to the re-aggregation of nanoparticles, reducing dispersion stability. Chemical surface functionalization, on the other hand, utilizes grafting and other methods to introduce active groups onto the nanoparticle surface, altering the polarity or hydrophilic-hydrophobicity of the nanoparticles to achieve uniform dispersion and stability of the dispersion system. However, this method is limited by the type of nanoparticle; different nanoparticles require specific modification methods, lacking universality. Furthermore, chemical modification methods are relatively complex, and the modification process can easily generate toxic and harmful substances, making large-scale industrial application difficult.

[0004] Therefore, there is still a need for improved methods to enhance the dispersion of nanoparticles in industry. Summary of the Invention

[0005] One object of the present invention is to provide an aqueous dispersion of nanoparticles that is suitable for preparation by a large-scale process and does not have the aforementioned defects.

[0006] The inventors of this invention have discovered that amphiphilic polymers with specific functional groups (i.e., UV photocrosslinking functional groups) can undergo physical adsorption and chemical modification with nanoparticles when ground and exposed to ultraviolet light, thereby successfully dispersing the nanoparticles and obtaining a stable aqueous dispersion of nanoparticles. Furthermore, using this amphiphilic polymer as a nanoparticle dispersant enables the industrial-scale preparation of aqueous dispersions of nanoparticles, and the resulting aqueous dispersions of nanoparticles exhibit ideal material properties, making them particularly suitable for fields such as coatings, inks (screen printing), and (3D) printing.

[0007] Therefore, this invention provides a nanoparticle dispersant comprising an amphiphilic polymer having an amino-containing backbone and UV-crosslinkable functional groups covalently bonded to the backbone, and further comprising hydrophilic polyether segments and hydrophobic organic segments. Preferably, the amphiphilic polymer has a comb-like structure, wherein the hydrophilic polyether segments are suspended on the backbone of the amphiphilic polymer. More preferably, the backbone of the amphiphilic polymer has amino terminal groups. In one embodiment of this invention, the nanoparticle dispersant comprising the amphiphilic polymer is self-crosslinkable under 365 nm UV light.

[0008] Another aspect of the present invention provides a method for a nanoparticle dispersant, comprising the steps of: i) providing a UV-crosslinkable compound containing two or more glycidyl groups; ii) subjecting the UV-crosslinkable compound containing two or more glycidyl groups and the polyglycidyl compound to an addition reaction with a polyfunctional amine to form the backbone of the amphiphilic polymer contained in the nanoparticle dispersant.

[0009] Another aspect of the present invention provides a stable aqueous dispersion of nanoparticles comprising nanoparticles and a nanoparticle dispersant, wherein the nanoparticle dispersant is as defined above or prepared according to the method of the present invention. Preferably, the stable aqueous dispersion of nanoparticles is formed by grinding a mixture of nanoparticles and the nanoparticle dispersant according to the present invention in the presence of an aqueous solvent and then irradiating it under ultraviolet light, preferably at 365 nm.

[0010] Another aspect of the present invention provides the application of aqueous dispersions of nanoparticles according to the present invention in aqueous coatings, inks (screen printing), and (3D) printing.

[0011] Details of one or more embodiments of the present invention are set forth in the following description. Other features, objects, and advantages of the invention will become clear from the description and claims.

[0012] definition

[0013] In this document, quantifiers are not used, and "at least one" and "one or more" are used interchangeably.

[0014] When a composition is described as including or comprising specific components, it is anticipated that optional components not covered by the present invention are not excluded from the composition, and that the composition may be constituted or composed of the components involved. Similarly, when a method is described as including or comprising specific process steps, it is anticipated that optional process steps not covered by the present invention are not excluded from the method, and that the method may be constituted or composed of the process steps involved.

[0015] For simplicity, this paper only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an undefined range; and any lower limit can be combined with other lower limits to form an undefined range, just as any upper limit can be combined with any other upper limit to form an undefined range. Furthermore, although not explicitly stated, every point or individual value between the endpoints of a range is included within that range. Therefore, each point or individual value can serve as its own lower or upper limit and be combined with any other point or individual value, or with other lower or upper limits, to form an undefined range.

[0016] In this paper, the term "amphiphilic polymer" refers to a macromolecule that is defined as a macromolecule that simultaneously contains hydrophilic and hydrophobic segments.

[0017] When used in relation to "amphiphilic polymers", the term "UV-crosslinkable functional group" refers to a group that can link with other organic segments on the amphiphilic polymer molecule, thereby causing crosslinking of the amphiphilic polymer containing the group itself or between them.

[0018] When used in relation to "amphiphilic polymers," the term "UV photosensitive group" refers to a group that is capable of covalently linking with other organic segments (e.g., hydrogen on a methylene group attached to a capped amino group) on an amphiphilic polymer molecule under ultraviolet light, such as 365 nm UV light, thereby causing crosslinking of the polymer itself or between segments. As an exemplary example, a UV photosensitive group includes benzophenone.

[0019] When used in relation to "amphiphilic polymers," the term "organic fragment" is defined as a portion of an organic compound comprising carbon, hydrogen, and optionally oxygen, nitrogen, sulfur, phosphorus, etc. In some embodiments of the invention, the organic fragment may be derived from polyglycidyl compounds, including but not limited to C3-C10 alkoxy polyethers or polyether amines with a molecular weight in the range of 382-6000 g / mol, or may be based on structures of bisphenol A, bisphenol F, bisphenol S and their derivatives, or C1-C20 alkyl groups and their derivatives.

[0020] When referring to "aqueous dispersions of nanoparticles", the term "stable" means that the aqueous dispersion, after being left at room temperature for a period of time, such as 1 week, 1 month, 3 months or 6 months, has less than 0.1% of precipitate or even no precipitate.

[0021] When used in this specification and claims, the terms “comprising” and “including” and their variations are not restrictive.

[0022] The terms "preferred" and "ideally" refer to embodiments of the invention that provide certain benefits in certain circumstances. However, other embodiments may also be preferred in the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of the invention. Attached Figure Description

[0023] Figure 1 The above is the 1H NMR spectrum of the photocrosslinkable comb-type polyetheramine dispersant according to Example 1 of the present invention;

[0024] Figure 2 The infrared spectrum of the photocrosslinkable comb-type polyetheramine dispersant according to Example 1 of the present invention;

[0025] Figure 3 The UV-Vis spectrum of the photocrosslinkable comb-type polyetheramine dispersant according to Example 1 of the present invention is shown.

[0026] Figure 4 These are TEM comparison images of the comb-type polyetheramine dispersant before and after photocrosslinking in Example 1 of the present invention, wherein the left image is before photocrosslinking and the right image is after photocrosslinking;

[0027] Figure 5 The UV-Vis spectrum of the pigment dispersion containing the comb-type polyetheramine dispersant according to Example 1 of the present invention;

[0028] Figure 6 The images show TEM comparisons of uncrosslinked and crosslinked pigment dispersions with the comb-type polyetheramine dispersant according to Example 1 of the present invention, with the left image showing the dispersion before and the right image showing the dispersion after crosslinking.

[0029] Figure 7 To assess the storage stability of uncrosslinked pigment dispersions (dispersion 1) and photocrosslinked pigment dispersions (dispersion 2) containing the comb-type polyetheramine dispersant according to Example 1 of the present invention, wherein (a) was stored at room temperature for 5 days; and (b) was stored at room temperature for 21 days;

[0030] Figure 8 Optical photographs of a photocrosslinked pigment dispersion containing the comb-type polyetheramine dispersant according to Example 1 of the present invention stored for 21 days in an organic solvent, at high pH, ​​and under thermal conditions (50°C), wherein (a) is in different organic solvents, (b) under different pH conditions, and (c) is stored at 50°C for different time periods.

[0031] Figure 9 Optical photographs of a photocrosslinked pigment dispersion containing the comb-type polyetheramine dispersant according to Example 1 of the present invention applied to 3D printed firmware and screen-printed patterns, wherein (a) is a 3D printed firmware; and (b) is a screen-printed pattern. Detailed Implementation

[0032] According to a first aspect of the present invention, a nanoparticle dispersant is provided, comprising an amphiphilic polymer having a main chain containing an amine group and UV-crosslinkable functional groups covalently bonded to the main chain, and the amphiphilic polymer further comprising hydrophilic polyether segments and hydrophobic organic segments.

[0033] The nanoparticle dispersant according to the present invention comprises an amphiphilic polymer. In the context of the present invention, the phrase "nanoparticle dispersant comprises an amphiphilic polymer" means that, in addition to the amphiphilic polymer (i.e., an amphiphilic polymer with hydrophilic polyether segments and hydrophobic organic segments and UV-crosslinkable functional groups), the dispersant according to the present invention may also contain other components that will not adversely affect the performance of the nanoparticle dispersant, including but not limited to organic solvents, raw materials for preparing the amphiphilic polymer, etc.

[0034] As described above, in the nanoparticle dispersant according to the present invention, the UV-crosslinkable functional groups contained in the amphiphilic polymer enable crosslinking of the amphiphilic polymers themselves or between them, forming a compact dispersant shell, thereby improving the dispersibility and dispersion stability of the nanoparticles in the dispersion medium. In embodiments of the present invention, nanoparticles refer to particles with a particle size between 1 and 100 nm, including but not limited to Epoxy Red, Phthalocyanine Blue, Carbon Black, or combinations thereof.

[0035] In one embodiment of the invention, the amphiphilic polymer contained in the nanoparticle dispersant has a UV photosensitive group. As described above, this UV photosensitive group can be activated by ultraviolet light, such as 365 nm ultraviolet light, and can react with other organic segments on the amphiphilic polymer molecule, such as hydrogen on a methylene group connected to a terminal amino group, thereby crosslinking the polymer. As an example, the UV photosensitive group may include benzophenone and other UV photosensitive groups known in the art.

[0036] The inventors of this invention have surprisingly discovered that when the amphiphilic polymer contained in the nanoparticle dispersant according to the invention has benzophenone as a UV-crosslinkable functional group, it undergoes crosslinking under ultraviolet light, such as 365 nm ultraviolet light. Without relying on any theory, the inventors hypothesize that upon exposure to ultraviolet light, the benzophenone group covalently bonds to the hydrogen on the methylene group attached to the terminal amino group, as shown below, thereby causing the amphiphilic polymer to crosslink itself or with each other.

[0037]

[0038] The cross-linked amphiphilic polymer formed in this way can tightly anchor the nanoparticles, avoiding the problem of nanoparticle re-aggregation caused by the desorption of the dispersant from the nanoparticles, and greatly improving the dispersion stability of the nanoparticle dispersion.

[0039] As described above, the amphiphilic polymer according to the invention has a backbone containing amine groups, including but not limited to tertiary and secondary amine groups. The presence of these amine groups results in the hyperbranched polymer according to the invention exhibiting a certain degree of hydrophilicity. In addition, the amphiphilic polymer may also comprise a backbone having any suitable compositional structure. The backbone may have different compositional structures, depending on various factors such as the materials used to form the backbone, cost, and the desired properties of the polymer. The backbone optionally contains one or more other stepwise growing linkages, such as amide linkages, ester linkages, carbonate linkages, ether linkages, imide linkages, imine linkages, urethane linkages, or combinations thereof.

[0040] In a preferred embodiment, the backbone of the amphiphilic polymer is formed via an addition reaction of a polyglycidyl compound, a UV-crosslinkable compound containing two or more glycidyl groups, and a polyfunctional amine. Preferably, the amino group of the polyfunctional amine is molarly in excess of the glycidyl group of the polyglycidyl compound. More preferably, the molar ratio of the amino group of the polyfunctional amine to the total glycidyl groups of the polyglycidyl compound and the UV-crosslinkable compound containing two or more glycidyl groups is in the range of 1.1:1 to 2:1, and more preferably in the range of 1.2:1 to 1.8:1. Therefore, in this embodiment, the backbone of the amphiphilic polymer is amino-terminated.

[0041] According to the present invention, a polyglycidyl compound refers to a monomer, oligomer, or polymer having two or more glycidyl groups in its molecule. Preferably, the polyglycidyl compound is selected from the group consisting of polyglycidyl esters, polyglycidyl ethers, or combinations thereof. In embodiments of the present invention, the polyglycidyl compound is a polyglycidyl ether. Examples of polyglycidyl ethers include diglycidyl ethers of polyphenols, diglycidyl ethers of polyols, polyglycidyl ethers of polyether resins, or combinations thereof. Suitable polyglycidyl ethers include, for example, diglycidyl ethers of polyphenols, such as diglycidyl ethers of resorcinol, diglycidyl ethers of catechol, diglycidyl ethers of hydroquinone, diglycidyl ethers of bisphenol A, diglycidyl ethers of bisphenol F, diglycidyl ethers of bisphenol S, and diglycidyl ethers of tetramethylbisphenol; diglycidyl ethers of aliphatic glycols and polyether glycols, such as C 2-24 Diglycidyl ether of alkylene glycols, diglycidyl ether of poly(ethylene oxide) glycols or diglycidyl ether of poly(propylene oxide) glycols; or combinations thereof.

[0042] Preferably, the polyfunctional amine includes aliphatic difunctional amines, aromatic difunctional amines, alicyclic difunctional amines, heterocyclic difunctional amines, polyethers containing two amino groups, polyesters containing two amino groups, polyacrylates containing two amino groups, or combinations thereof, and more preferably polyethers containing two amino groups or combinations thereof.

[0043] According to the present invention, the amphiphilic polymer may contain hydrophilic polyether segments to impart further hydrophilicity to the amphiphilic polymer, and / or may also contain hydrophobic polyether segments to impart further hydrophobicity to the amphiphilic polymer. The presence of the above-mentioned hydrophilic and / or hydrophobic polyether segments results in better dispersion, wherein the molar ratio of the hydrophilic polyether segment to the hydrophobic polyether segment is in the range of 10:0 to 0:10, preferably in the range of 10:1 to 1:10, more preferably in the range of 8:1 to 1:8, even more preferably in the range of 4:1 to 1:4, even more preferably in the range of 2:1 to 1:2, and especially more preferably in the range of 1:1.

[0044] In some embodiments of the invention, the hydrophilic polyether fragment is derived from polyoxyethylene ether or ether amine with a molecular weight in the range of 174-6000 g / mol.

[0045] In some embodiments of the invention, the hydrophobic organic fragment is derived from C3-C10 alkoxy polyethers or polyetheramines with a molecular weight in the range of 382-6000 g / mol, or is based on the structure of bisphenol A, bisphenol F, or bisphenol S and its derivatives, C1-C20 alkyl groups and their derivative groups, or combinations thereof. Preferably, the hydrophobic organic fragment is derived from C3-C10 alkoxy polyethers or polyetheramines with a molecular weight in the range of 382-6000 g / mol. 10 Alkoxy polyether. In one specific embodiment of the invention, the hydrophobic organic fragment is derived from polyoxypropylene ether or polyether amine with a molecular weight in the range of 382-6000 g / mol.

[0046] According to the present invention, the amphiphilic polymer can have a wide molecular weight distribution. Preferably, the amphiphilic polymer disclosed herein can have a number-average molecular weight in the range of 2000 to 30,000 g / mol, more preferably in the range of 2000 to 20,000 g / mol, more preferably in the range of 2500 to 20,000 g / mol, and even more preferably in the range of 3000 to 18,000 g / mol. The number-average molecular weight can be determined using GPC.

[0047] The nanoparticle dispersant according to the present invention can be prepared by: i) providing a UV-crosslinkable compound containing two or more glycidyl groups; ii) subjecting the UV-crosslinkable compound containing two or more glycidyl groups, the polyglycidyl compound, and a polyfunctional amine to an addition reaction to form the backbone of the amphiphilic polymer contained in the nanoparticle dispersant.

[0048] Therefore, in a particular embodiment of the invention, the amphiphilic polymer contained in the nanoparticle dispersant has the structure described in formula (I):

[0049]

[0050] Where p represents a UV-crosslinkable functional group, R1 represents an organic fragment derived from a polyglycidyl compound, x represents an integer from 0 to 20; R2 represents y, where y represents hydrogen or methyl, y represents an integer from 8 to 30, z represents an integer from 3 to 9, and m and n represent integers from 1 to 100.

[0051] According to another aspect of the present invention, a method for preparing a nanoparticle dispersant is provided, comprising i) providing a UV-crosslinkable compound containing two or more glycidyl groups; ii) subjecting the UV-crosslinkable compound containing two or more glycidyl groups and the polyglycidyl compound to an addition reaction with a polyfunctional amine to form the backbone of the amphiphilic polymer contained in the nanoparticle dispersant.

[0052] In the method for preparing a nanoparticle dispersant according to the present invention, step i) comprises performing an addition reaction between epichlorohydrin and a UV-crosslinkable compound containing hydroxyl functional groups to obtain the UV-crosslinkable compound containing two or more glycidyl groups.

[0053] In embodiments of the invention, a UV-crosslinkable compound containing two or more glycidyl groups is used to introduce UV-crosslinkable functional groups into the backbone of the amphiphilic polymer. The aforementioned UV-crosslinkable compound containing two or more glycidyl groups may be commercially available or synthetic. In one embodiment of the invention, the UV-crosslinkable compound containing two or more glycidyl groups is synthesized by reacting a hydroxyl-containing UV-crosslinkable compound with epichlorohydrin to form the UV-crosslinkable compound containing two or more glycidyl groups.

[0054] In step i) above, the appropriate conditions for the reaction to be carried out depend on various factors, including the type of UV-crosslinkable compound with hydroxyl groups used, the presence or absence of a catalyst, and if present, the type of catalyst, etc., which can be determined by those skilled in the art based on experience.

[0055] In one specific embodiment of the invention, the UV-crosslinkable compound containing two or more glycidyl groups is formed by reacting a hydroxyl-functionalized benzophenone, such as 4,4'-dihydroxybenzophenone, with epichlorohydrin. Preferably, in this embodiment, 4,4'-dihydroxybenzophenone and epichlorohydrin are refluxed in an organic solvent under an inert atmosphere in the presence of anhydrous potassium carbonate for 24 hours to form the UV-crosslinkable compound containing two or more glycidyl groups.

[0056] In the method for preparing a nanoparticle dispersant according to the present invention, step ii) includes performing an addition reaction between the UV-crosslinkable compound containing two or more glycidyl groups, the polyglycidyl compound obtained in step i), and a polyfunctional amine to introduce the UV-crosslinkable functional group into the backbone of the amphiphilic polymer contained in the nanoparticle dispersant.

[0057] As described above, a polyglycidyl compound refers to a monomer, oligomer, or polymer having two or more glycidyl groups in its molecule. Preferably, the polyglycidyl compound is selected from the group consisting of polyglycidyl esters, polyglycidyl ethers, or combinations thereof. In embodiments of the invention, the polyglycidyl compound is a polyglycidyl ether. As examples of polyglycidyl ethers, diglycidyl ethers of polyphenols, diglycidyl ethers of polyols, or combinations thereof can be used. Suitable polyglycidyl ethers include, for example, diglycidyl ethers of polyphenols, such as diglycidyl ethers of resorcinol, diglycidyl ethers of catechol, diglycidyl ethers of hydroquinone, diglycidyl ethers of bisphenol A, diglycidyl ethers of bisphenol F, diglycidyl ethers of bisphenol S, and diglycidyl ethers of tetramethylbisphenol; diglycidyl ethers of aliphatic glycols and polyether glycols, such as C 2-24 Diglycidyl ethers of alkylene glycols (e.g., polyethylene glycol diglycidyl ether), diglycidyl ethers of poly(ethylene oxide) glycol or diglycidyl ethers of poly(propylene oxide) glycol; or combinations thereof.

[0058] As mentioned above, polyfunctional amines are amines with two or more amino groups in their molecules. The amino group of a polyfunctional amine undergoes an epoxy-ammonia click reaction with a glycidyl group (i.e., an epoxy group) to form the main chain of an amphiphilic polymer.

[0059] Preferably, the polyfunctional amine comprises aliphatic difunctional amines, aromatic difunctional amines, alicyclic difunctional amines, heterocyclic difunctional amines, polyethers containing two amino groups, polyesters containing two amino groups, polyacrylates containing two amino groups, or combinations thereof, preferably polyethers containing two amino groups. In embodiments of the invention, any commercially available polyfunctional amine can be used, such as Jeffamine L100 from Huntman.

[0060] In one embodiment of the invention, in step ii), the amino group of the polyfunctional amine is in excess relative to the total glycidyl groups of the polyglycidyl compound and the UV-crosslinkable compound containing two or more glycidyl groups, thereby obtaining an amphiphilic polymer with an amino terminal group. Preferably, the molar ratio of the amino group of the polyfunctional amine to the total glycidyl groups of the polyglycidyl compound and the UV-crosslinkable compound containing two or more glycidyl groups is in the range of 1.1:1 to 2:1, more preferably in the range of 1.2:1 to 1.8:1.

[0061] In step ii) above, the appropriate conditions for the reaction to be carried out depend on various factors, including the type of polyglycidyl compound or polyfunctional amine used, the presence or absence of a catalyst, and if present, the type of catalyst, etc., which can be determined by those skilled in the art based on experience.

[0062] In some embodiments of the present invention, steps i) and ii) are both carried out under the protection of an inert gas, wherein the inert gas is selected from the group consisting of nitrogen, argon, or combinations thereof.

[0063] In some embodiments of the present invention, steps i) and ii) are both carried out in an organic solvent, wherein the organic solvent is selected from the group consisting of ketones, propylene glycol monomethyl ether, 1,4-dioxane, dimethyl sulfoxide, N,N-dimethylformamide and N,N-dimethylacetamide.

[0064] The inventors of this invention were surprised to discover that the mixture of nanoparticle dispersant and nanoparticles prepared by the above method according to the present invention can form a particularly stable aqueous dispersion of nanoparticles after being exposed to ultraviolet light.

[0065] Therefore, another aspect of the present invention provides a stable aqueous dispersion of nanoparticles comprising a dispersant according to the invention, nanoparticles, and an aqueous solvent, wherein the dispersant is photocrosslinked. Preferably, the nanoparticles are nanoscale pigments, including golden red, phthalocyanine blue, carbon black, or combinations thereof.

[0066] In an embodiment of the invention, the aqueous dispersion of nanoparticles is formed by grinding a mixture of nanoparticles and a dispersant of the nanoparticles of the invention in the presence of an aqueous solvent and then subjecting it to ultraviolet light irradiation. Preferably, the grinding is performed using a grinding apparatus selected from a grinding mill, a horizontal sand mill, a vertical sand mill, a multi-functional disperser, and a vibrating disperser. In the above embodiments, the grinding is performed at a temperature of 3-95°C, and / or the weight ratio of the nanoparticles to the amphiphilic hyperbranched dispersant is in the range of 1:10 to 10:1, preferably in the range of 1:2 to 2:1, and more preferably 2:1. Preferably, the ultraviolet irradiation is performed using 365nm UV light.

[0067] In one specific embodiment of the present invention, a method for preparing a stable aqueous dispersion of nanoparticles includes the following steps:

[0068] Step 1: Mix a polyether containing diepoxy, a monocyclic, polycyclic, or fused-ring photosensitive compound containing diepoxy, and a co-initiator containing a primary amine in an organic solvent to obtain a mixed solution. The amount of the polyether containing diepoxy and the monocyclic, polycyclic, or fused-ring photosensitive compound containing diepoxy is less than the amount of the co-initiator containing a primary amine.

[0069] Step 2: The mixture is heated and stirred under inert gas protection using a heating and stirring device, causing the amino and epoxy groups to undergo a click chemical reaction to obtain a solution of polymer molecules.

[0070] Step 3: Separate the polymer molecules from the solution using a poor solvent to obtain a turbid product.

[0071] Step 4: Remove the organic solvent and undesirable solvent by rotary evaporation, and dry to obtain a photocrosslinkable comb-type polyetheramine dispersant.

[0072] Step 5: Mix the pigment and the obtained comb-type polyetheramine dispersant in water, and grind the mixture of pigment and dispersant thoroughly using a grinding device. Let it stand to obtain the supernatant, which is the pigment dispersion.

[0073] Step 6: Irradiate the pigment dispersion with ultraviolet light to obtain a photocrosslinked pigment dispersion.

[0074] The photocrosslinked pigment dispersion obtained above has excellent stability and is suitable for applications such as photopolymer 3D printing, screen printing, and coatings.

[0075] To further illustrate this aspect of the invention, some non-limiting embodiments are provided below:

[0076] Embodiment 1. A nanoparticle dispersant comprising an amphiphilic polymer having a main chain containing an amine group and UV-crosslinkable functional groups covalently bonded to the main chain, and the amphiphilic polymer further comprising hydrophilic polyether segments and hydrophobic organic segments.

[0077] Embodiment 2. The dispersant as described in Embodiment 1, wherein the UV-crosslinkable functional group includes a UV-sensitive group, preferably including a benzophenone group.

[0078] Embodiment 3. The dispersant as described in any one of Embodiments 1 to 2, wherein the hydrophilic polyether fragment is derived from polyoxyethylene ether or ether amine with a molecular weight in the range of 174-6000 g / mol.

[0079] Embodiment 4. The dispersant as described in Embodiments 1 to 3, wherein the hydrophobic organic fragment is derived from C3-C molecules with a molecular weight in the range of 382-6000 g / mol. 10 Alkoxy polyethers or polyetheramines, or structures based on bisphenol A, bisphenol F or bisphenol S and their derivatives, C1-C20 alkyl groups and their derivatives or combinations thereof.

[0080] Embodiment 5. The dispersant as described in any one of Embodiments 1 to 4, wherein the weight-average molecular weight of the amphiphilic polymer is in the range of 2000-30000 g / mol.

[0081] Embodiment 6. The dispersant as described in any one of Embodiments 1 to 5, wherein the amphiphilic polymer has a comb-like structure, and wherein the hydrophilic polyether fragments are suspended on the main chain of the amphiphilic polymer.

[0082] Embodiment 7. The dispersant as described in any one of Embodiments 1 to 6, wherein the main chain of the amphiphilic polymer has amino terminal groups.

[0083] Embodiment 8. The nanoparticle dispersant as described in any one of Embodiments 6 to 7, wherein the amphiphilic polymer has the structure described in formula (I):

[0084]

[0085] Where p represents a UV-crosslinkable functional group, R1 represents an organic fragment derived from a polyglycidyl compound, x represents an integer from 0 to 20; R2 represents y, where y represents hydrogen or methyl, y represents an integer from 8 to 30, z represents an integer from 3 to 9, and m and n represent integers from 1 to 100.

[0086] Embodiment 9. The dispersant as described in any one of Embodiments 1 to 8, wherein the nanoparticles are nano-sized pigments, including Epoxy Red, Phthalocyanine Blue, Carbon Black, or combinations thereof.

[0087] Embodiment 10. The dispersant as described in any one of Embodiments 1 to 9, wherein the amphiphilic polymer is self-crosslinkable under 365 nm UV light.

[0088] Implementation 11. A method for preparing a nanoparticle dispersant, comprising the following steps: i) providing a UV-crosslinkable compound containing two or more glycidyl groups; ii) subjecting the UV-crosslinkable compound containing two or more glycidyl groups and the polyglycidyl compound to an addition reaction with a polyfunctional amine to form the backbone of the amphiphilic polymer contained in the nanoparticle dispersant.

[0089] Embodiment 12. The method of Embodiment 11, wherein step i) of providing a UV-crosslinkable compound containing two or more glycidyl groups comprises performing an addition reaction between epichlorohydrin and a UV-crosslinkable compound containing hydroxyl functional groups to obtain the UV-crosslinkable compound containing two or more glycidyl groups.

[0090] Embodiment 13. The method as described in Embodiment 11, wherein the polyfunctional amine includes aliphatic difunctional amines, aromatic difunctional amines, alicyclic difunctional amines, heterocyclic difunctional amines, polyethers containing two amino groups, polyesters containing two amino groups, polyacrylates containing two amino groups, or combinations thereof, preferably polyethers containing two amino groups.

[0091] Embodiment 14. The method as described in Embodiment 11, wherein the polyglycidyl compound is selected from the group consisting of polyglycidyl esters, polyglycidyl ethers, or combinations thereof, preferably polyglycidyl ethers.

[0092] Implementation Method 15. The method as described in Implementation Method 14, wherein the polyglycidyl ether is selected from the group consisting of diglycidyl ethers of polyphenols, diglycidyl ethers of polyols, diglycidyl ethers of polypolyols, and combinations thereof.

[0093] Embodiment 16. The method as described in any one of Embodiments 11 to 15, wherein the amino group of the polyfunctional amine is in molar excess relative to the total glycidyl groups of the polyglycidyl compound and the UV-crosslinkable compound containing two or more glycidyl groups, preferably in the range of 1.1:1 to 2:1, more preferably in the range of 1.2:1 to 1.8:1.

[0094] Implementation Method 17. The method as described in Implementation Methods 11 to 15, wherein steps i) and ii) are both carried out in an organic solvent, wherein the organic solvent is selected from the group consisting of alcohols, ethers, ketones, aromatics, halogenated aromatics, propylene glycol monomethyl ether, 1,4-dioxane, dimethyl sulfoxide, N,N-dimethylformamide and N,N-dimethylacetamide.

[0095] Embodiment 18. A stable aqueous dispersion of nanoparticles comprising a dispersant as described in any one of Embodiments 1 to 10 or a dispersant obtained by any one of Embodiments 11 to 17, nanoparticles, and an aqueous solvent, wherein the dispersant is photocrosslinked.

[0096] Embodiment 19. An aqueous dispersion of nanoparticles as described in Embodiment 18, wherein the nanoparticles are nanoscale pigments, including Epoxy Red, Phthalocyanine Blue, Carbon Black, or combinations thereof.

[0097] Embodiment 20. An aqueous dispersion of nanoparticles as described in Embodiment 18, wherein the aqueous dispersion of nanoparticles is formed by grinding a mixture of the nanoparticles and the nanoparticle dispersant in the presence of an aqueous solvent and subjecting it to ultraviolet irradiation.

[0098] Implementation Method 21. An aqueous dispersion of nanoparticles as described in Implementation Method 20, wherein the grinding is performed using a grinding device selected from a grinder, a horizontal sand mill, a vertical sand mill, a multi-functional disperser, and a vibrating disperser at a temperature of 3-95°C.

[0099] Embodiment 22. An aqueous dispersion of nanoparticles as described in Embodiment 20, wherein the ultraviolet irradiation is performed using 365 nm UV light.

[0100] Embodiment 23. An aqueous dispersion of nanoparticles as described in Embodiment 20, wherein the weight ratio of the nanoparticles to the dispersant is in the range of 1:10 to 10:1, preferably in the range of 1:2 to 2:1, and more preferably 2:1.

[0101] Implementation Method 24. Application of the aqueous dispersion of nanoparticles described in any one of Implementation Methods 18-23 in coatings, screen printing, and (3D) printing.

[0102] The advantages of the above-mentioned comb-shaped polyetheramine dispersants are: (1) simple synthesis and strong molecular design capabilities, the preparation and molecular design of dispersants can be achieved through one-step photoclick; (2) high dispersion stability and strong universality, based on physical adsorption, the comb-shaped molecules have more anchoring points on the surface of nanoparticles, forming an adsorption shell; based on chemical modification, the pre-formed physical adsorption shell is covalently cross-linked through the photochemical reaction of functional groups, so that the dispersant is locked on the surface of nanoparticles, effectively solving the problems of adsorption balance (physical adsorption) and limited types of nanoparticles (chemical modification). Moreover, the advantages of the above-mentioned dispersant preparation method are: (1) simple preparation process, one-step synthesis, no pretreatment of raw materials is required; (2) the proportion of different blocks in the dispersant molecule can be flexibly adjusted according to product needs to obtain polyetheramine dispersants with different properties; (3) the raw materials have all been industrialized.

[0103] The following examples describe the disclosure of this invention in more detail. These examples are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of this disclosure. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are based on weight, and all reagents used in the examples are commercially available and ready for use without further processing.

[0104] Example

[0105] Example 1:

[0106] A photocrosslinkable comb-type polyetheramine dispersant, the preparation method of which mainly includes the following steps:

[0107] (1) Preparation of monocyclic, polycyclic, or fused-ring photosensitive compounds containing dicyclic oxides. 1.129 g of 4,4′-dihydroxybenzophenone, 3.42 g of epichlorohydrin, and 1.46 g of anhydrous potassium carbonate were mixed in 300 mL of butanone. Under nitrogen protection, the mixture was heated to 80 °C and refluxed for 24 h. After the reaction was complete, the mixture was cooled to room temperature, and the product was washed with butanone and filtered under reduced pressure. The resulting solid was dried to obtain a yellow powdery solid product, namely the functionalized monocyclic, polycyclic, or fused-ring photosensitive compound-1, with a yield of approximately 90%.

[0108] (2) Preparation of photocrosslinkable comb-type polyetheramine dispersant. Ethylene glycol diglycidyl ether (EG-DE, Mn = 174 g / mol, 0.02 mol), the functionalized monocyclic, polycyclic, or fused-ring photosensitive compound-1 (DEBP, 0.01 mol) prepared in (1) and Jeffamine L100 (Hunstman, Mn = 1000 g / mol, 0.05 mol) were dissolved in 100 mL of propylene glycol monomethyl ether. Under nitrogen protection, the temperature was raised to 130 °C and the reaction was carried out for 24 h. After the reaction was completed, the mixture was cooled to room temperature, and the above solution was added to n-hexane to precipitate the product. After removing the supernatant, the solvent was removed by rotary evaporation. The resulting liquid was dried to obtain a yellow-brown viscous liquid product, which is the photocrosslinkable comb-type polyetheramine dispersant-1, with a yield of approximately 80%.

[0109] Figure 1 The image shows the structure and 1H NMR spectrum of the target product. Figure 2 This is the infrared spectrum of the target product.

[0110] (3) The comb-type polyetheramine dispersant obtained in (2) was dispersed in water at 0.01 mg / ml and photocrosslinking was achieved in the water under 365 nm ultraviolet light.

[0111] Figure 4 The UV-Vis spectrum of the comb-type polyetheramine dispersant. Figure 5 These are TEM images comparing comb-type polyetheramine before and after photocrosslinking in water.

[0112] (4) Preparation of photocrosslinked pigment dispersion. Different types of pigments and dispersants were added to deionized water. The initial pigment concentration was 10 mg / ml, and the concentration of the comb-type polyetheramine dispersant obtained in (2) was 5 mg / ml. The dispersion was then ground with ZrO2 steel balls with a diameter of 2.0 mm. After ball milling for 4 hours, the resulting dispersion was left to stand overnight. The supernatant was then carefully collected by filtration. The supernatant was irradiated with 365 nm ultraviolet light to obtain the photocrosslinked pigment dispersion-1.

[0113] Figure 5 The ultraviolet-visible spectrum of the pigment dispersion. Figure 6These are TEM images comparing the pigment dispersion before and after photocrosslinking. Figure 7 To compare the storage stability of pigment dispersions before and after photocrosslinking with the addition of comb-type polyetheramine dispersant. Figure 8 The stability of the photocrosslinked pigment dispersion under organic solvent, high pH, ​​and heat conditions for 21 days was measured.

[0114] (5) Application of photocrosslinked pigment dispersion. 0.01% of the photocrosslinked pigment dispersion-1 obtained in (4) was added to the photocurable resin and nylon paste, and 3D photocurable printing and screen printing were performed to obtain 3D printed firmware and screen printed patterns.

[0115] Figure 9 Optical photographs of 3D printed firmware and screen-printed patterns, where a represents the 3D printed firmware and b represents the screen-printed pattern.

[0116] Example 2:

[0117] A photocrosslinkable comb-type polyetheramine dispersant, the preparation method of which mainly includes the following steps:

[0118] (1) Preparation of monocyclic, polycyclic, or fused-ring photosensitive compounds containing dicyclic oxides. 1.129 g of 4,4′-dihydroxybenzophenone, 3.42 g of epichlorohydrin, and 1.46 g of anhydrous potassium carbonate were mixed in 300 mL of butanone. Under nitrogen protection, the mixture was heated to 80 °C and refluxed for 24 h. After the reaction was complete, the mixture was cooled to room temperature, and the product was washed with butanone and filtered under reduced pressure. The resulting solid was dried to obtain a yellow powdery solid product, namely the functionalized monocyclic, polycyclic, or fused-ring photosensitive compound-1, with a yield of approximately 90%.

[0119] (2) Preparation of photocrosslinkable comb-type polyetheramine dispersant. Ethylene glycol diglycidyl ether (EG-DE, Mn = 174 g / mol, 0.03 mol), the monocyclic, polycyclic, or fused-ring photosensitive compound-2 containing diepoxy groups prepared in (1) (0.01 mol), and Jeffamine L100 (Hunstman, Mn = 1000 g / mol, 0.06 mol) were dissolved in 100 mL of propylene glycol monomethyl ether. Under nitrogen protection, the temperature was raised to 130 °C and the reaction was carried out for 24 h. After the reaction was completed, the mixture was cooled to room temperature, and the above solution was added to n-hexane to precipitate the product. After removing the supernatant, the solvent was removed by rotary evaporation. The resulting liquid was dried to obtain a yellow-brown viscous liquid product, which is the photocrosslinkable comb-type polyetheramine dispersant-2, with a yield of approximately 80%.

[0120] (3) The comb-type polyetheramine dispersant obtained in (2) was dispersed in water at 0.01 mg / ml and photocrosslinking was achieved in the water under 365 nm ultraviolet light.

[0121] (4) Preparation of photocrosslinked pigment dispersion. Different types of pigments and dispersants were added to deionized water. The initial pigment concentration was 10 mg / ml, and the concentration of the comb-type polyetheramine dispersant obtained in (2) was 5 mg / ml. The mixture was then ground with ZrO2 steel balls with a diameter of 2.0 mm. After ball milling for 4 hours, the resulting dispersion was left to stand overnight. The supernatant was then carefully collected by filtration. The supernatant was irradiated with 365 nm ultraviolet light to obtain the photocrosslinked pigment dispersion-2.

[0122] (5) Application of photocrosslinked pigment dispersion. 0.01% of the photocrosslinked pigment dispersion-2 obtained in (4) was added to the photocurable resin and nylon paste, and 3D photocurable printing and screen printing were performed to obtain 3D printed firmware and screen printed patterns.

[0123] Example 3:

[0124] A photocrosslinkable comb-type polyetheramine dispersant, the preparation method of which mainly includes the following steps:

[0125] (1) Preparation of monocyclic, polycyclic, or fused-ring photosensitive compounds containing dicyclic oxides. 1.129 g of 4,4′-dihydroxybenzophenone, 3.42 g of epichlorohydrin, and 1.46 g of anhydrous potassium carbonate were mixed in 300 mL of butanone. Under nitrogen protection, the mixture was heated to 80 °C and refluxed for 24 h. After the reaction was complete, the mixture was cooled to room temperature, and the product was washed with butanone and filtered under reduced pressure. The resulting solid was dried to obtain a yellow powdery solid product, namely the functionalized monocyclic, polycyclic, or fused-ring photosensitive compound-1, with a yield of approximately 90%.

[0126] (2) Preparation of photocrosslinkable comb-type polyetheramine dispersant. Ethylene glycol diglycidyl ether (EG-DE, Mn = 174 g / mol, 0.04 mol), the monocyclic, polycyclic, or fused-ring photosensitive compound-3 (0.01 mol) containing diepoxy rings prepared in (1), and Jeffamine L100 (Hunstman, Mn = 1000 g / mol, 0.07 mol) were dissolved in 100 mL of propylene glycol monomethyl ether. Under nitrogen protection, the temperature was raised to 130 °C and the reaction was carried out for 24 h. After the reaction was completed, the mixture was cooled to room temperature, and the above solution was added to n-hexane to precipitate the product. After removing the supernatant, the solvent was removed by rotary evaporation. The resulting liquid was dried to obtain a yellow-brown viscous liquid product, which is the photocrosslinkable comb-type polyetheramine dispersant-2, with a yield of approximately 80%.

[0127] (3) The comb-type polyetheramine dispersant obtained in (2) was dispersed in water at 0.01 mg / ml and photocrosslinking was achieved in the water under 365 nm ultraviolet light.

[0128] (4) Preparation of photocrosslinked pigment dispersion. Different types of pigments and dispersants were added to deionized water. The initial pigment concentration was 10 mg / ml, and the concentration of the comb-type polyetheramine dispersant obtained in (2) was 5 mg / ml. The mixture was then ground with ZrO2 steel balls with a diameter of 2.0 mm. After ball milling for 4 hours, the resulting dispersion was left to stand overnight. The supernatant was then carefully collected by filtration. The supernatant was irradiated with 365 nm ultraviolet light to obtain the photocrosslinked pigment dispersion-3.

[0129] (5) Application of photocrosslinked pigment dispersion. 0.01% of the photocrosslinked pigment dispersion-3 obtained in (4) was added to the photocurable resin and nylon paste, and 3D photocurable printing and screen printing were performed to obtain 3D printed firmware and screen printed patterns.

[0130] Example 4:

[0131] A photocrosslinkable comb-type polyetheramine dispersant, the preparation method of which mainly includes the following steps:

[0132] (1) Preparation of monocyclic, polycyclic, or fused-ring photosensitive compounds containing dicyclic oxides. 1.129 g of 4,4′-dihydroxybenzophenone, 3.42 g of epichlorohydrin, and 1.46 g of anhydrous potassium carbonate were mixed in 300 mL of butanone. Under nitrogen protection, the mixture was heated to 80 °C and refluxed for 24 h. After the reaction was complete, the mixture was cooled to room temperature, and the product was washed with butanone and filtered under reduced pressure. The resulting solid was dried to obtain a yellow powdery solid product, namely the functionalized monocyclic, polycyclic, or fused-ring photosensitive compound-1, with a yield of approximately 90%.

[0133] (2) Preparation of photocrosslinkable comb-type polyetheramine dispersant. Ethylene glycol diglycidyl ether (EG-DE, Mn = 174 g / mol, 0.07 mol), the monocyclic, polycyclic, or fused-ring photosensitive compound-3 (0.01 mol) containing diepoxy rings prepared in (1), and Jeffamine L100 (Hunstman, Mn = 1000 g / mol, 0.1 mol) were dissolved in 100 mL of propylene glycol monomethyl ether. Under nitrogen protection, the temperature was raised to 120 °C and the reaction was carried out for 24 h. After the reaction was completed, the mixture was cooled to room temperature, and the above solution was added to n-hexane to precipitate the product. After removing the supernatant, the solvent was removed by rotary evaporation. The resulting liquid was dried to obtain a yellow-brown viscous liquid product, which is the photocrosslinkable comb-type polyetheramine dispersant-4, with a yield of approximately 80%.

[0134] (3) The comb-type polyetheramine dispersant obtained in (2) was dispersed in water at 0.01 mg / ml and photocrosslinking was achieved in the water under 365 nm ultraviolet light.

[0135] (4) Preparation of photocrosslinked pigment dispersion. Different types of pigments and dispersants were added to deionized water. The initial pigment concentration was 10 mg / ml, and the concentration of the comb-type polyetheramine dispersant obtained in (2) was 5 mg / ml. The mixture was then ground with ZrO2 steel balls with a diameter of 2.0 mm. After ball milling for 4 hours, the resulting dispersion was left to stand overnight. The supernatant was then carefully collected by filtration. The supernatant was irradiated with 365 nm ultraviolet light to obtain the photocrosslinked pigment dispersion-4.

[0136] (5) Application of photocrosslinked pigment dispersion. 0.01% of the photocrosslinked pigment dispersion-4 obtained in (4) was added to the photocurable resin and nylon paste, and 3D photocurable printing and screen printing were performed to obtain 3D printed firmware and screen printed patterns.

[0137] As can be seen from the above experimental results, the dispersant according to the present invention can disperse nanoparticles and significantly improve the dispersion stability of the nanoparticle dispersion after photocrosslinking.

[0138] Although the present invention has been described with reference to numerous embodiments and examples, those skilled in the art will recognize that other embodiments can be designed based on the disclosure of the present invention without departing from the scope and spirit of the invention.

Claims

1. A nanoparticle dispersant comprising an amphiphilic polymer having a backbone containing amine groups and UV-photocrosslinkable functional groups covalently bonded to the backbone, and further comprising hydrophilic polyether segments and hydrophobic organic segments, wherein, The UV-crosslinkable functional group includes a benzophenone group.

2. The nanoparticle dispersant as described in claim 1, wherein, The hydrophilic polyether fragments are derived from polyoxyethylene ethers or ether amines with a molecular weight in the range of 174-6000 g / mol.

3. The nanoparticle dispersant as described in claim 1, wherein, The amphiphilic polymer has a comb-like structure, wherein the hydrophilic polyether fragments are suspended on the main chain of the amphiphilic polymer.

4. The nanoparticle dispersant as described in claim 1, wherein, The main chain of the amphiphilic polymer has amino terminal groups.

5. The nanoparticle dispersant according to any one of claims 3 to 4, wherein, The amphiphilic polymer has the structure described in formula (I): Where p represents a UV-crosslinkable functional group, R1 represents an organic fragment derived from a polyglycidyl compound, x represents an integer from 0 to 20; R2 represents hydrogen or methyl, y represents an integer from 8 to 30, z represents an integer from 3 to 9, and m and n represent integers from 1 to 100.

6. The dispersant of claim 1, wherein, The amphiphilic polymer is self-crosslinkable under 365 nm UV light.

7. A method for preparing a nanoparticle dispersant, comprising the steps of: i) providing a UV-crosslinkable compound containing two or more glycidyl groups; ii) subjecting the UV-crosslinkable compound containing two or more glycidyl groups, the polyglycidyl compound, and a polyfunctional amine to an addition reaction to form the backbone of the amphiphilic polymer contained in the nanoparticle dispersant, wherein, The UV-crosslinkable functional group includes a benzophenone group.

8. The method of claim 7, wherein, Step i) of providing a UV-crosslinkable compound containing two or more glycidyl groups includes performing an addition reaction between epichlorohydrin and a UV-crosslinkable compound containing hydroxyl functional groups to obtain the UV-crosslinkable compound containing two or more glycidyl groups.

9. A stable aqueous dispersion of nanoparticles, comprising the dispersant according to any one of claims 1 to 6 or the dispersant obtained by the method according to any one of claims 7-8, nanoparticles, and an aqueous solvent, wherein, The dispersant is cross-linked by UV light.

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