Self-cleaning nanocomposite emulsion, preparation method and application thereof

Abstract

The application relates to the technical field of nano composite emulsion, in particular to a self-cleaning nano composite emulsion and a preparation method and application thereof, and the preparation raw materials comprise a vinyl functionalized SiO2 nano dispersion liquid, a functionalized alginic acid salt, a vinyl monomer, an initiator, an emulsifier and deionized water; according to weight parts, the preparation raw materials of the vinyl functionalized SiO2 nano dispersion liquid comprise tetraethyl orthosilicate 1-2 parts, ammonia water 0.01-0.02 parts, ethanol 20-30 parts, deionized water 4-6 parts and a silane coupling agent 0.5-0.6 parts; the vinyl monomer comprises butyl acrylate and methyl methacrylate, and the mass ratio of the butyl acrylate to the methyl methacrylate is (70-80):(20-30). The nano composite emulsion provided by the application simultaneously shows excellent effects in terms of hydrophilicity, optical performance, adhesion and stain resistance, and solves the pain points of mutual exclusion of existing coating performances.

Description

Technical Field

[0001] This invention relates to the field of nanocomposite emulsion technology, specifically to a self-cleaning nanocomposite emulsion, its preparation method, and its application. Background Technology

[0002] Self-cleaning coatings, which can remove surface stains through rainwater or water washing, reducing manual maintenance costs, have been widely used in construction, transportation, and medical fields. Currently, mainstream self-cleaning coatings are mainly divided into two categories:

[0003] Superhydrophilic coatings rely on hydrophilic groups (such as hydroxyl and carboxyl groups) on the material surface to allow water to spread and carry away stains. These are commonly found in polysaccharide and silica-based coatings. For example, Chinese invention patent CN104629617B provides an inorganic-organic hybrid superhydrophilic self-cleaning coating. However, such coatings generally suffer from poor mechanical properties (low hardness, weak adhesion), are prone to wear, and their hydrophilicity tends to decrease after long-term use.

[0004] Superhydrophobic coatings achieve the "lotus effect" through micro-nano structures and low surface energy materials (such as fluorides and silanes), but require multiple steps to construct the microstructure, making the preparation process complex. Furthermore, the hydrophobic layer is prone to failure due to wear. In addition, fluoride materials have the drawbacks of poor biocompatibility and insufficient environmental friendliness.

[0005] In addition, existing self-cleaning coatings have the drawback of poor performance synergy: for example, adding SiO2 can increase hardness but reduce hydrophilicity; introducing flexible polymers can improve flexibility but weaken stain resistance; and most coatings rely on chemically synthesized raw materials, which have insufficient biocompatibility and are difficult to apply to fields such as medical devices and food contact. Summary of the Invention

[0006] To address the problems existing in the prior art, the first aspect of the present invention provides a self-cleaning nanocomposite emulsion, the raw materials for which include vinyl-functionalized SiO2 nanodispersion, functionalized alginate, vinyl monomers, initiator, emulsifier and deionized water;

[0007] The raw materials for preparing the vinyl-functionalized SiO2 nano-dispersion, by weight, include 1-2 parts of tetraethyl orthosilicate, 0.01-0.02 parts of ammonia, 20-30 parts of ethanol, 4-6 parts of deionized water, and 0.5-0.6 parts of silane coupling agent.

[0008] The vinyl monomers include butyl acrylate and methyl methacrylate, wherein the mass ratio of butyl acrylate to methyl methacrylate is (70-80):(20-30).

[0009] This invention employs specific vinyl monomers, butyl acrylate and methyl methacrylate, and controls their mass ratio to (70-80):(20-30) to achieve a composite coating with balanced mechanical properties, stable hydrophilicity, and excellent antifouling properties. The likely reason is that butyl acrylate (BA) is a flexible monomer (containing long-chain butyl groups, exhibiting strong rotational properties), while methyl methacrylate (MMA) is a rigid monomer (containing methyl and ester groups, exhibiting significant steric hindrance). When the ratio is (70-80):(20-30), a balance between flexibility and rigidity is achieved, ensuring coating adhesion and maintaining sufficient hardness. Furthermore, the polarity of functionalized alginate, containing hydrophilic groups (hydroxyl and carboxyl groups) and hydrophobic grafted chains (vinyl groups introduced by GMA), is matched, enabling uniform free radical copolymerization of the three (BA / MMA / functionalized alginate), thus preventing alginate aggregation due to polarity mismatch. Secondly, the organic soft shell formed at this mass ratio has optimal density, which can reduce the penetration and adsorption of stains such as talcum powder. At the same time, combined with the hydrophilic effect of functionalized alginate, it achieves low residue rate and prolongs the self-cleaning effect.

[0010] In one embodiment, the silane coupling agent comprises methacryloxysilane.

[0011] In one embodiment, the methacryloyloxysilane is methacryloyloxypropyltrimethoxysilane (MPS).

[0012] In one embodiment, the preparation method of the vinyl-functionalized SiO2 nanodispersion includes the following steps:

[0013] Tetraethyl orthosilicate and 80-90 wt% ethanol are mixed and stirred for 30-40 min to obtain a tetraethyl orthosilicate ethanol solution;

[0014] Mix ammonia, deionized water and the remaining ethanol, stir for 15-20 min, and add the tetraethyl orthosilicate ethanol solution dropwise at a rate of 300 μL / min. React at 50 °C for 2-3 h to obtain SiO2 nano solution.

[0015] A silane coupling agent was added to the SiO2 nano solution, and the mixture was stirred for 90-100 min and then aged overnight to obtain the vinyl-functionalized SiO2 nano dispersion.

[0016] In one embodiment, the raw materials for preparing the functionalized alginate include 1-2 parts alginate solution and 0.2-1 parts glycidyl methacrylate (GMA) by weight.

[0017] In one embodiment, the alginate solution is an aqueous solution of sodium alginate.

[0018] In one embodiment, the sodium alginate aqueous solution has a mass fraction of 3-5%.

[0019] In one embodiment, the method for preparing the functionalized alginate includes the following steps:

[0020] Alginate was dissolved in deionized water and stirred until completely dissolved. The pH of the solution was adjusted to 8-10 to obtain an aqueous solution of sodium alginate. Glycidyl methacrylate was added while stirring. The mixture was heated to 60-70℃ and reacted for 6-7 hours. The mixture was then transferred to a dialysis membrane and dialyzed for 24-36 hours. After drying at 100℃, the functionalized alginate was obtained.

[0021] In one embodiment, the pH of the sodium alginate aqueous solution is adjusted using a NaOH solution.

[0022] In one embodiment, the weight ratio of the functionalized alginate to the vinyl monomer is (0.004-0.006):1. Examples include 0.004:1, 0.005:1, and 0.006:1.

[0023] In one embodiment, the initiator comprises potassium persulfate.

[0024] In one embodiment, the emulsifier includes Tween 80.

[0025] A second aspect of this invention provides a method for preparing a self-cleaning nanocomposite emulsion, comprising at least the following steps:

[0026] S1. Stir and mix deionized water and emulsifier until completely dissolved, then add vinyl-functionalized SiO2 nano-dispersion and stir to disperse evenly.

[0027] S2. Weigh 40wt% of vinyl monomers, functionalized alginate and initiator, mix and dissolve them, and add them to the system in step S1. Heat to 70-80℃ and add the remaining vinyl monomers dropwise at a rate of 300-400μL / min. After the addition is complete, continue stirring for 2-3 hours and cool to room temperature to obtain the composite emulsion.

[0028] The third aspect of this invention provides an application of a self-cleaning nanocomposite emulsion in the preparation of a self-cleaning nanocomposite coating.

[0029] Beneficial effects

[0030] 1. This invention uses specific vinyl monomers butyl acrylate and methyl methacrylate, and controls their mass ratio to (70-80): (20-30) to achieve a composite coating with balanced mechanical properties, stable hydrophilicity, and excellent anti-fouling properties.

[0031] 2. This invention controls the raw materials and dosage to obtain a vinyl-functionalized SiO2 nano-dispersion. The vinyl double bonds grafted by MPS can fully copolymerize with the double bonds of BA / MMA / functionalized alginate, anchoring SiO2 in the organic soft shell and ensuring its uniform dispersion. At the same time, the fully modified SiO2 by MPS can form a stable covalent bond with the organic soft shell. Under wear or temperature changes, the SiO2 hard core is not easy to fall off, and the soft shell is not easy to separate from the hard core, thus improving the durability of the coating.

[0032] 3. This invention achieves the technical effects of hydrophilicity, high hardness, strong adhesion, and low stain resistance by using a functionalized SiO2 hard core and a BA / MMA / alginate soft shell structure, thus solving the problem of mutually exclusive performance of existing coatings.

[0033] 4. This invention uses marine polysaccharide alginate as the hydrophilic core to replace traditional chemically synthesized hydrophilic materials. It has excellent biocompatibility and can be extended to medical devices and food contact fields. It can be coated on a variety of substrates such as glass, metal, and plastic, and is suitable for scenarios such as building self-cleaning, medical antibacterial, and automotive antifouling.

[0034] 5. This invention is prepared using an emulsion copolymerization process, which allows for easy control of process parameters and is suitable for large-scale production. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention. Experimental methods not specifying specific conditions in the embodiments were performed under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0036] Example 1

[0037] The first aspect of this example provides a self-cleaning nanocomposite emulsion, which, by weight, is prepared from 1 part vinyl-functionalized SiO2 nanodispersion, 0.01 parts functionalized alginate, 2.5 parts vinyl monomers, 0.2 parts initiator, 0.5 parts emulsifier, and 5 parts deionized water.

[0038] The raw materials for preparing the vinyl-functionalized SiO2 nano-dispersion, by weight, include 1 part tetraethyl orthosilicate, 0.01 part ammonia, 25 parts ethanol, 5 parts deionized water, and 0.5 parts silane coupling agent.

[0039] The silane coupling agent is methacryloyloxypropyltrimethoxysilane.

[0040] The preparation method of the vinyl-functionalized SiO2 nano-dispersion includes the following steps:

[0041] Tetraethyl orthosilicate and 80 wt% ethanol were mixed and stirred for 30 min to obtain a tetraethyl orthosilicate ethanol solution;

[0042] Ammonia, deionized water and remaining ethanol were mixed and stirred for 15 min. The mixture was then added dropwise to the tetraethyl orthosilicate ethanol solution at a rate of 300 μL / min. The reaction was carried out at 50 °C for 2 h to obtain SiO2 nano solution.

[0043] A silane coupling agent was added to the SiO2 nano solution, and the mixture was stirred for 90 minutes and then aged overnight to obtain the vinyl-functionalized SiO2 nano dispersion.

[0044] The raw materials for preparing the functionalized alginate include 1 part alginate solution and 0.6 parts glycidyl methacrylate by weight.

[0045] The alginate solution is an aqueous solution of sodium alginate, and the mass fraction of the aqueous solution of sodium alginate is 3%.

[0046] The preparation method of the functionalized alginate includes the following steps:

[0047] Alginate was dissolved in deionized water and stirred until completely dissolved. The pH of the solution was adjusted to 8 to obtain an aqueous solution of sodium alginate. Glycidyl methacrylate was added while stirring. The mixture was heated to 60°C and reacted for 6 hours. The mixture was then transferred to a dialysis membrane and dialyzed for 24 hours. The solution was dried at 100°C to obtain the functionalized alginate.

[0048] The vinyl monomers are butyl acrylate and methyl methacrylate, and the mass ratio of butyl acrylate to methyl methacrylate is 70:30.

[0049] The initiator is potassium persulfate.

[0050] The emulsifier is Tween 80.

[0051] The second aspect of this example provides a method for preparing a self-cleaning nanocomposite emulsion, comprising the following steps:

[0052] S1. Stir and mix deionized water and emulsifier until completely dissolved, then add vinyl-functionalized SiO2 nano-dispersion and stir to disperse evenly.

[0053] S2. Weigh 40wt% of vinyl monomers, functionalized alginate and initiator, mix and dissolve them, and add them to the system in step S1. Heat to 75℃ and add the remaining vinyl monomers dropwise at a rate of 300μL / min. After the addition is complete, continue stirring for 2.5h and cool to room temperature to obtain the composite emulsion.

[0054] The third aspect of this example provides an application of a self-cleaning nanocomposite emulsion in the preparation of a self-cleaning nanocomposite coating.

[0055] Example 2

[0056] The specific implementation method of this example is the same as that of Example 1, except that, according to the weight parts, the raw materials for preparing the vinyl functionalized SiO2 nano-dispersion include 1 part of tetraethyl orthosilicate, 0.02 parts of ammonia, 25 parts of ethanol, 5 parts of deionized water, and 0.5 parts of silane coupling agent.

[0057] Example 3

[0058] The specific implementation method in this example is the same as in Example 1, except that the preparation method of the functionalized alginate includes the following steps:

[0059] Alginate was dissolved in deionized water and stirred until completely dissolved. The pH of the solution was adjusted to 9 to obtain an aqueous solution of sodium alginate. Glycidyl methacrylate was added while stirring. The mixture was heated to 60°C and reacted for 6 hours. The mixture was then transferred to a dialysis membrane and dialyzed for 24 hours. The solution was dried at 100°C to obtain the functionalized alginate.

[0060] Example 4

[0061] The specific implementation method in this example is the same as in Example 1, except that the preparation method of the functionalized alginate includes the following steps:

[0062] Alginate was dissolved in deionized water and stirred until completely dissolved. The pH of the solution was adjusted to 10 to obtain an aqueous solution of sodium alginate. Glycidyl methacrylate was added while stirring. The mixture was heated to 60°C and reacted for 6 hours. The mixture was then transferred to a dialysis membrane and dialyzed for 24 hours. The solution was dried at 100°C to obtain the functionalized alginate.

[0063] Example 5

[0064] The specific implementation method in this example is the same as in Example 1, except that the mass fraction of the sodium alginate aqueous solution is 5%.

[0065] The preparation method of the functionalized alginate includes the following steps:

[0066] Alginate was dissolved in deionized water and stirred until completely dissolved. The pH of the solution was adjusted to 8 to obtain an aqueous solution of sodium alginate. Glycidyl methacrylate was added while stirring. The mixture was heated to 60°C and reacted for 6 hours. The mixture was then transferred to a dialysis membrane and dialyzed for 36 hours. The solution was dried at 100°C to obtain the functionalized alginate.

[0067] Example 6

[0068] The specific implementation method in this example is the same as in Example 1, except that, according to the weight parts, the raw materials for preparing the functionalized alginate include 1 part of alginate solution and 0.2 parts of glycidyl methacrylate.

[0069] Example 7

[0070] The specific implementation method in this example is the same as in Example 1, except that, according to the weight parts, the raw materials for preparing the functionalized alginate include 1 part alginate solution and 1 part glycidyl methacrylate.

[0071] Example 8

[0072] The specific implementation method in this example is the same as in Example 1, except that the mass ratio of butyl acrylate to methyl methacrylate is 80:20.

[0073] Comparative Example 1

[0074] The specific implementation method in this example is the same as in Example 1, except that no silane coupling agent is added to modify the SiO2 nano-dispersion in this example.

[0075] The preparation method of the SiO2 nano-dispersion includes:

[0076] Tetraethyl orthosilicate and 80 wt% ethanol were mixed and stirred for 30 min to obtain a tetraethyl orthosilicate ethanol solution;

[0077] Ammonia, deionized water and remaining ethanol were mixed and stirred for 15 min. The mixture was then added dropwise to the tetraethyl orthosilicate ethanol solution at a rate of 300 μL / min and reacted at 50 °C for 2 h to obtain SiO2 nano-dispersion.

[0078] Comparative Example 2

[0079] The specific implementation method of this example is the same as that of Example 1, except that, according to the weight parts, the raw materials for preparing the vinyl functionalized SiO2 nano-dispersion include 1 part of tetraethyl orthosilicate, 0.03 parts of ammonia, 25 parts of ethanol, 5 parts of deionized water, and 0.5 parts of silane coupling agent.

[0080] Comparative Example 3

[0081] The specific implementation method of this example is the same as that of Example 1, except that, according to the weight parts, the raw materials for preparing the vinyl functionalized SiO2 nano-dispersion include 1 part of tetraethyl orthosilicate, 0.05 parts of ammonia, 25 parts of ethanol, 5 parts of deionized water, and 0.5 parts of silane coupling agent.

[0082] Comparative Example 4

[0083] The specific implementation method of this example is the same as that of Example 1, except that, according to the weight parts, the raw materials for preparing the vinyl functionalized SiO2 nano-dispersion include 1 part of tetraethyl orthosilicate, 0.03 parts of ammonia, 25 parts of ethanol, 5 parts of deionized water, and 0.3 parts of silane coupling agent.

[0084] Comparative Example 5

[0085] The specific implementation method of this example is the same as that of Example 1, except that, according to the weight parts, the raw materials for preparing the vinyl functionalized SiO2 nano-dispersion include 1 part of tetraethyl orthosilicate, 0.03 parts of ammonia, 25 parts of ethanol, 5 parts of deionized water, and 0.7 parts of silane coupling agent.

[0086] Comparative Example 6

[0087] The specific implementation method of this example is the same as that of Example 1, except that the second aspect of this example provides a method for preparing a self-cleaning nanocomposite emulsion, including the following steps:

[0088] S1. Stir and mix deionized water and emulsifier until completely dissolved, then add vinyl-functionalized SiO2 nano-dispersion and stir to disperse evenly.

[0089] S2. The vinyl monomer, functionalized alginate and initiator are mixed and dissolved, and then added to the system of step S1. The mixture is heated to 75°C and stirred for 2.5 hours. After cooling to room temperature, the composite emulsion is obtained.

[0090] Comparative Example 7

[0091] The specific implementation method in this example is the same as in Example 1, except that the mass ratio of butyl acrylate to methyl methacrylate is 60:40.

[0092] Comparative Example 8

[0093] The specific implementation method in this example is the same as in Example 1, except that the mass ratio of butyl acrylate to methyl methacrylate is 90:10.

[0094] Performance testing

[0095] 1. Hydrophilicity test:

[0096] The products of the examples and comparative examples were coated onto a 75mm×150mm×1mm glass slide to prepare sample pieces. After drying at room temperature for 48 hours, the water contact angle was measured using a water contact angle meter MIT-PHa: water droplets were dropped onto the sample piece, and the water contact angle was measured using the height measurement method. Each sample piece was measured three times, and the average value was taken as the result.

[0097] 2. Optical performance testing:

[0098] The products of the examples and comparative examples were coated onto a 75mm×150mm×1mm glass slide to make samples. After drying at room temperature for 48 hours, the transparency and haze of the coating were tested using a YH1200 haze meter. Each sample was measured three times, and the average value was taken as the result.

[0099] 3. Pencil hardness test:

[0100] The products of the examples and comparative examples were coated onto a 75mm×150mm×1mm glass slide to make sample pieces. After drying at room temperature for 48 hours, they were tested using a pencil hardness tester according to GBT6739-2022.

[0101] 4. Adhesion test:

[0102] The products of the examples and comparative examples were coated onto glass slides measuring 75mm×150mm×1mm to prepare samples. After drying at room temperature for 48 hours, the adhesion was measured using an adhesion tester in accordance with GB 1720-1979.

[0103] 5. Antifouling performance test:

[0104] The products of the examples and comparative examples were coated onto a 75mm×150mm×1mm glass slide to make samples. After drying at room temperature, the samples were placed on a fixed object and the tilt angle was adjusted to 45°. 2g of talc powder was evenly spread in a straight line, and the talc powder was observed to fall off. After standing for 5 minutes, the mass of residual talc powder on the glass plate was measured to determine the anti-fouling ability of the coating.

[0105] The test results are shown in Table 1.

[0106] Table 1

[0107]

[0108] As can be seen from the table above, Examples 1-8 of this application exhibit superior performance in terms of hydrophilicity, optical properties, adhesion, and antifouling properties compared to the comparative examples.

Claims

1. A self-cleaning nanocomposite emulsion, characterized in that, The raw materials for preparation include vinyl-functionalized SiO2 nano-dispersion, functionalized alginate, vinyl monomers, initiator, emulsifier and deionized water; The raw materials for preparing the vinyl-functionalized SiO2 nano-dispersion, by weight, include 1-2 parts of tetraethyl orthosilicate, 0.01-0.02 parts of ammonia, 20-30 parts of ethanol, 4-6 parts of deionized water, and 0.5-0.6 parts of silane coupling agent; the silane coupling agent includes methacryloxysilane. The preparation method of the vinyl-functionalized SiO2 nano-dispersion includes the following steps: Mix tetraethyl orthosilicate and 80-90 wt% ethanol and stir for 30-40 min to obtain a tetraethyl orthosilicate ethanol solution. Mix ammonia, deionized water and the remaining ethanol, stir for 15-20 min, and add the tetraethyl orthosilicate ethanol solution dropwise at a rate of 300 μL / min. React at 50 °C for 2-3 h to obtain SiO2 nano solution. A silane coupling agent was added to the SiO2 nano solution, and the mixture was stirred for 90-100 min and then aged overnight to obtain the vinyl-functionalized SiO2 nano dispersion. The vinyl monomers are butyl acrylate and methyl methacrylate, and the mass ratio of butyl acrylate to methyl methacrylate is (70-80):(20-30). The raw materials for preparing the functionalized alginate include 1-2 parts alginate solution and 0.2-1 parts glycidyl methacrylate, by weight. The weight ratio of the functionalized alginate to the vinyl monomer is (0.004-0.006):1; The preparation method of the self-cleaning nanocomposite emulsion includes at least the following steps: S1. Stir and mix deionized water and emulsifier until completely dissolved, then add vinyl-functionalized SiO2 nano-dispersion and stir to disperse evenly. S2. Weigh 40wt% of vinyl monomers, functionalized alginate and initiator, mix and dissolve them, and add them to the system in step S1. Heat to 70-80℃ and add the remaining vinyl monomers dropwise at a rate of 300-400μL / min. After the addition is complete, continue stirring for 2-3 hours and cool to room temperature to obtain the composite emulsion.

2. An application of the self-cleaning nanocomposite emulsion according to claim 1, characterized in that, It is applied in the preparation of self-cleaning nanocomposite coatings.

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