Antibacterial ultra-light shaping paste and preparation method thereof

Abstract

The application relates to the field of shaping materials, and discloses an antibacterial super-light shaping paste and a preparation method thereof. The antibacterial super-light shaping paste comprises the following raw materials: 8-12 parts of a polymer emulsion, 0.05-0.15 parts of antibacterial expandable microspheres, 2-4 parts of fillers, and 2-4 parts of water. The antibacterial expandable microspheres comprise a thermoplastic polymer shell, a volatile expanding agent filled in the thermoplastic polymer shell, and nano-silver grown in situ on the surface of the thermoplastic polymer shell. The antibacterial expandable microspheres are prepared by ingeniously modifying the expandable microspheres with hydroxyl groups, nitrile groups and carbonyl groups on the surface through the mode of in-situ deposition of nano-silver, the antibacterial expandable microspheres are mixed with the polymer emulsion, the fillers and various kinds of additives, the antibacterial expandable microspheres are made to swell in volume through heating, become antibacterial swelling microspheres, and thus the shaping paste with the characteristics of safety, environmental protection, antibacterial property and light weight is prepared.

Description

Technical Field

[0001] This invention relates to the field of shaping materials, and more particularly to an antibacterial ultralight shaping paste and its preparation method. Background Technology

[0002] In the creation of paintings, the expression of material texture is a crucial aspect for artists. Typically, artists use different colors of paint to layer and shape, achieving a textured, uneven surface to enhance the viewer's visual experience and evoke empathy. However, the high price of traditional oil paints results in high costs and low production volumes for purely handmade decorative oil paintings, making it difficult to meet the large demand from domestic and international consumers.

[0003] Against this backdrop, in recent years, a product called modeling paste has been invented and widely used in the creation and production of decorative oil paintings. For example, in the early stages of creating a decorative oil painting, ordinary painters can use inexpensive modeling paste instead of oil paint, employing brushes, scrapers, rollers, and other methods to create three-dimensional shapes and textures on the canvas. Finally, oil paint is used to refine these textures, significantly reducing the use of oil paint and thus lowering the production cost of decorative paintings. For instance, invention patent CN201510118774.9 proposes a modeling paste preparation process that significantly reduces costs while maintaining the performance of the modeling paste by adding a large amount of white glue. However, this method of preparing modeling paste contains harmful ingredients such as toluene. Furthermore, the use of large amounts of calcium carbonate or titanium dioxide powder in its reinforcing fillers results in large decorative oil paintings that are heavy, increasing costs during subsequent transportation and installation. More importantly, decorative oil paintings are prone to mold and fungal growth after years of environmental erosion, making their preservation and maintenance extremely complicated.

[0004] In conclusion, it is imperative to develop a shaping cream that is safe, environmentally friendly, antibacterial, and lightweight. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides an antibacterial ultralight shaping paste and its preparation method. This invention ingeniously modifies the surface of expandable microspheres containing hydroxyl, nitrile, and carbonyl groups by in-situ deposition of silver nanoparticles, obtaining antibacterial expandable microspheres. Furthermore, these microspheres are mixed with polymer emulsions, fillers, and various additives, and then heated to cause the antibacterial expandable microspheres to expand in volume, thus transforming them into antibacterial expanded microspheres, thereby producing a shaping paste with safe, environmentally friendly, antibacterial, and lightweight characteristics.

[0006] The specific technical solution of this invention is as follows:

[0007] In a first aspect, the present invention provides an antibacterial ultralight shaping cream, comprising the following raw materials in parts by weight: 8-12 parts polymer emulsion, 0.05-0.15 parts antibacterial expandable microspheres, 2-4 parts filler, and 2-4 parts water.

[0008] The antibacterial expandable microspheres comprise: a thermoplastic polymer shell, a volatile expander filling the interior of the thermoplastic polymer shell, and nano-silver grown in situ on the surface of the thermoplastic polymer shell.

[0009] First, the ultralight shaping cream of this invention does not contain toluene or other organic solvents that are harmful to the human body and the environment.

[0010] Secondly, the raw materials of the ultralight shaping paste of the present invention contain antibacterial expandable microspheres, on which nano-silver grows in situ on the surface of the microspheres, thereby giving the ultralight shaping paste an antibacterial and anti-mildew effect, making the decorative oil paintings created using the shaping paste as a base have better corrosion resistance.

[0011] Furthermore, the antibacterial expandable microspheres of this invention use a thermoplastic polymer as the shell and are filled with a volatile expander. Their expansion principle is as follows: Figure 2 As shown, when the antibacterial expandable microspheres are heated, the volatile expanding agent (e.g., low-boiling-point alkanes) boils, increasing the gas pressure. Simultaneously, the thermoplastic polymer shell softens and deforms, causing the microspheres to expand in volume, transforming them into antibacterial expanded microspheres. When the temperature decreases, the microsphere shell cools and solidifies, maintaining the expanded volume of the antibacterial expanded microspheres.

[0012] As a preferred option, such as Figure 1 As shown, the preparation method of the antibacterial expandable microspheres includes the following steps:

[0013] (1) Mix expandable microspheres containing hydroxyl, nitrile and carbonyl groups on the surface of the shell with silver salt solution and stir evenly;

[0014] (2) Centrifuge the mixture obtained in step (1) to obtain expandable microsphere precipitates with silver ions adsorbed on the surface;

[0015] (3) Redisperse the precipitate obtained in step (2) in water, add a reducing agent and stir to react;

[0016] (4) The dispersion obtained in step (3) is centrifuged to separate the precipitate, and after washing and drying, antibacterial expandable microspheres are obtained.

[0017] The preparation principle of the antibacterial ultralight shaping paste of this invention is as follows: The expandable microspheres selected in this invention contain a large number of hydroxyl, carbonyl, and nitrile groups on their surface. The unbonded lone pairs of electrons on the oxygen and nitrogen atoms in these hydroxyl, carbonyl, and nitrile groups can coordinate with the empty orbitals of silver ions in the silver salt solution to form coordinate bonds, thereby adsorbing a large number of silver ions. Subsequently, a reducing agent is added to reduce the silver ions, generating nano-silver on the surface of the microspheres in situ, thus obtaining antibacterial expandable microspheres. Further, these microspheres are mixed with polymer emulsions, fillers, and various additives, and then heated to cause the antibacterial expandable microspheres to expand in volume, transforming them into antibacterial expandable microspheres, thereby obtaining a shaping paste with safe, environmentally friendly, antibacterial, and lightweight characteristics. Figure 2 As shown, when heated, the low-boiling-point volatile expander inside the microsphere shell boils, increasing the gas pressure, and the thermoplastic polymer shell of the microsphere softens and deforms, causing the microsphere to expand in volume, becoming antibacterial expanded microspheres. When the temperature decreases, the outer shell of the microsphere cools and sets, maintaining the expanded volume of the antibacterial expanded microspheres.

[0018] Preferably, in step (1), the expandable microspheres are coated with a volatile expanding agent using a thermoplastic polymer shell.

[0019] Preferably, in step (1), the thermoplastic polymer is selected from at least one of polyacrylonitrile, polyacrylate, polyacrylamide, and polyacrylic acid.

[0020] The reason for choosing the above-mentioned thermoplastic polymer in this invention is that its functional groups can effectively adsorb silver ions, and its softening deformation temperature is consistent with the preparation process temperature of this invention.

[0021] Preferably, in step (1), the volatile expanding agent is a low-boiling-point hydrocarbon, preferably one or more of n-pentane, isopentane, neopentane, butane and isobutane, and more preferably n-pentane with a boiling point of 36.1°C.

[0022] The reason for choosing the above-mentioned volatile expanding agent in this invention is that its volatilization temperature matches the preparation process temperature of this invention.

[0023] Preferably, in step (1), the silver salt solution is a silver nitrate solution with a concentration of 0.8-1.0M; the ratio of the expandable microspheres to the silver salt solution is 0.5-0.7g:4-6mL.

[0024] This invention discovered in experiments that during the heating and expansion of antibacterial expandable microspheres into antibacterial expandable microspheres, the thickness of the thermoplastic polymer shell gradually thins due to the significant increase in volume. This affects the stability of the silver nanoparticles attached to its surface; if the bonding force between the silver nanoparticles and the thermoplastic polymer shell is weak, they are prone to detachment. Ultimately, this invention found that the morphology of the silver nanoparticles has a significant impact on their detachment during the expansion of antibacterial expandable microspheres into antibacterial expandable microspheres, and the morphology of the silver nanoparticles is highly correlated with the concentration and amount of silver nitrate. Finally, this invention found that under the above-mentioned parameter conditions, silver nanoparticles with ideal particle morphology and size can be successfully obtained. If the concentration and amount of silver nitrate are too high, it is easy to form plate-like silver elements with larger particle sizes, which are prone to detachment in large quantities during the heating and expansion process into antibacterial expandable microspheres.

[0025] Preferably, in step (1), the stirring speed is 500-700 rpm and the time is 10-20 min.

[0026] Preferably, in step (2), the centrifugation speed is 3000-4000 rpm and the time is 3-5 min.

[0027] Preferably, in step (3), the reducing agent is an ascorbic acid solution with a concentration of 0.1-0.2M; the ratio of water to ascorbic acid solution is 8-12mL:8-12mL.

[0028] Preferably, in step (3), the stirring speed is 500-700 rpm and the time is 1-2 h.

[0029] Preferably, in step (4), the centrifugation speed is 3000-4000 rpm and the time is 3-5 min; the washing is done by washing with water and ethanol successively, 2-4 times; the drying temperature is 30-40℃ and the time is 24-48 h.

[0030] Preferably, the polymer emulsion is selected from one or more of pure acrylic emulsion, silicone acrylic emulsion, and styrene acrylic emulsion; more preferably, it is pure acrylic emulsion with a solid content of 50-60 wt%; the filler is calcium carbonate.

[0031] Preferably, the ultralight shaping paste further includes 0.3-0.7 parts of dispersant, 0.05-0.15 parts of wetting agent, 0.5-1.5 parts of defoamer, and 0.2-0.4 parts of thickener.

[0032] Preferably, the dispersant is selected from one or more of sodium tripolyphosphate, sodium hexametaphosphate and sodium pyrophosphate, triethylhexyl phosphate, sodium dodecyl sulfate, methylpentanol, cellulose derivatives, sodium polyacrylate, guru gum, fatty acid polyethylene glycol esters and polyethers; sodium polyacrylate is more preferred.

[0033] Preferably, the wetting agent is selected from one or more of alkyl polyoxyethylene ethers, polyether silicones, and nonionic fluorocarbon polymers; alkyl polyoxyethylene ethers are more preferred.

[0034] Preferably, the defoamer is selected from one or more of organosilicon, mineral oil, polyether, and high carbon alcohols with 7-9 carbon atoms; more preferably, FB-50 type organosilicon defoamer is selected.

[0035] Preferably, the thickener is selected from one or more of sodium methyl cellulose, polyacrylate and associative polyurethane; sodium carboxymethyl cellulose is more preferred.

[0036] Secondly, the present invention provides a method for preparing an antibacterial ultralight shaping cream, comprising the following steps:

[0037] (a) Mix the polymer emulsion, dispersant, wetting agent, defoamer and water by stirring;

[0038] (b) Add antibacterial expandable microspheres, fillers and thickeners and stir until homogeneous;

[0039] (c) The resulting mixture is preheated until the thermoplastic polymer shell of the antibacterial expandable microspheres softens. Then, the mixture is stirred and heated to expand the antibacterial expandable microspheres into antibacterial expandable microspheres. Finally, the mixture is cooled in an ice water bath to cool and solidify the antibacterial expandable microspheres, thus obtaining an antibacterial ultralight shaping paste.

[0040] Preferably, in steps (a)-(c), the stirring speed is 300-500 rpm and the time is 20-40 min.

[0041] Preferably, in step (c), the preheating temperature is 45-55℃ and the preheating time is 5-10 min; the stirring speed is 300-500 rpm and the time is 20-40 min; the heating temperature is 70-90℃; and the temperature of the ice water bath is 2-8℃ and the cooling time is 30-60 min.

[0042] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention ingeniously modifies the surface of expandable microspheres containing hydroxyl, carbonyl, and nitrile groups by in-situ deposition of nano-silver, thus preparing antibacterial expandable microspheres. Furthermore, these microspheres are mixed with polymer emulsions, fillers, and various additives, and then heated to cause the antibacterial expandable microspheres to expand in volume, transforming them into antibacterial expandable microspheres, thereby obtaining a shaping paste with safe, environmentally friendly, antibacterial, and lightweight characteristics. Attached Figure Description

[0043] Figure 1 This is a schematic diagram illustrating the preparation principle of antibacterial expandable microspheres.

[0044] Figure 2 This is a diagram illustrating the expansion principle of expandable microspheres.

[0045] Figure 3 The FTIR spectrum of the MS140WS expandable microspheres from the Middle East in Example 1 is shown below.

[0046] Figure 4 The XRD pattern of the antibacterial expandable microspheres in Example 1;

[0047] Figure 5 This is a SEM image of the expandable microspheres before modification in Example 1;

[0048] Figure 6 This is a SEM image of the antibacterial expandable microspheres modified with nano-silver in Example 1;

[0049] Figure 7 This is a SEM image of the nano-silver modified antibacterial expanded microspheres after heating and expansion in Example 1;

[0050] Figure 8 SEM image of the silver-modified antibacterial expandable microspheres in Comparative Example 1;

[0051] Figure 9 SEM image of the silver-modified antibacterial expanded microspheres after heating and expansion in Comparative Example 1;

[0052] Figure 10 This is a weight comparison chart of the antibacterial ultralight shaping paste and the shaping paste using calcium carbonate filler in Example 1;

[0053] Figure 11 This is an illustration of the shaping effect of the antibacterial ultralight shaping cream on a canvas in Example 1.

[0054] Figure 12 This is a diagram of the antibacterial zone experiment of the antibacterial ultralight shaping cream in Example 1. Detailed Implementation

[0055] The present invention will be further described below with reference to embodiments.

[0056] General Implementation Examples

[0057] An antibacterial ultralight shaping paste comprises the following raw materials in parts by weight: 8-12 parts polymer emulsion, 0.05-0.15 parts antibacterial expandable microspheres, 2-4 parts filler, 0.3-0.7 parts dispersant, 0.05-0.15 parts wetting agent, 0.5-1.5 parts defoamer, 0.2-0.4 parts thickener, and 2-4 parts water. Wherein:

[0058] The polymer emulsion is selected from one or more of pure acrylic emulsion, silicone acrylic emulsion, and styrene acrylic emulsion; pure acrylic emulsion is further preferred, with a solid content of 50-60 wt%; the filler is calcium carbonate.

[0059] The dispersant is selected from one or more of sodium tripolyphosphate, sodium hexametaphosphate and sodium pyrophosphate, triethylhexylphosphate, sodium dodecyl sulfate, methylpentanol, cellulose derivatives, sodium polyacrylate, guru gum, fatty acid polyethylene glycol esters and polyethers; sodium polyacrylate is further preferred.

[0060] The wetting agent is selected from one or more of alkyl polyoxyethylene ethers, polyether silicones, and nonionic fluorocarbon polymers; alkyl polyoxyethylene ethers are more preferred.

[0061] The defoamer is selected from one or more of organosilicon, mineral oil, polyether, and high carbon alcohols with 7-9 carbon atoms; FB-50 type organosilicon defoamer is further preferred.

[0062] The thickener is selected from one or more of sodium carboxymethyl cellulose, polyacrylate and associative polyurethane; sodium carboxymethyl cellulose is more preferred.

[0063] The antibacterial expandable microspheres comprise: a thermoplastic polymer shell, a volatile expanding agent filling the interior of the thermoplastic polymer shell, and nano-silver grown in situ on the surface of the thermoplastic polymer shell. The preparation method is as follows: Figure 1 As shown, it includes:

[0064] (1) Mix 0.5-0.7 g of expandable microspheres (thermoplastic polymer shells filled with volatile expanders) with 4-6 mL of silver salt solution (preferably 0.8-1.0 M silver nitrate solution) and stir (500-700 rpm, 10-20 min) until homogeneous. The thermoplastic polymer shell is selected from at least one of polyacrylonitrile, polyacrylate, polyacrylamide, and polyacrylic acid; the volatile expander is a low-boiling hydrocarbon, preferably one or more of n-pentane, isopentane, neopentane, butane, and isobutane, and more preferably n-pentane with a boiling point of 36.1 °C.

[0065] (2) Centrifuge the mixture obtained in step (1) (3000-4000 rpm, 3-5 min) to obtain expandable microsphere precipitates with silver ions adsorbed on the surface.

[0066] (3) Redisperse the precipitate obtained in step (2) in 8-12 mL of water, add 8-12 mL of reducing agent (preferably 0.1-0.2 M ascorbic acid solution) and stir the reaction (500-700 rpm, 1-2 h).

[0067] (4) Centrifuge the dispersion obtained in step (3) (3000-4000 rpm, 3-5 min) to separate the precipitate, wash (wash with water and ethanol 2-4 times) and dry (30-40℃, 24-48 h) to obtain antibacterial expandable microspheres.

[0068] A method for preparing an antibacterial ultralight shaping cream includes the following steps:

[0069] (a) Mix the polymer emulsion, dispersant, wetting agent, defoamer and water and stir (300-500 rpm, 20-40 min).

[0070] (b) Add antibacterial expandable microspheres, fillers and thickeners and stir (300-500 rpm, 20-40 min) until homogeneous.

[0071] (c) Preheat the above mixture at 45-55℃ for 5-10 minutes, then stir at 300-500 rpm for 20-40 minutes and heat at 70-90℃ to expand the antibacterial expandable microspheres into antibacterial expandable microspheres. Finally, transfer it to an ice water bath at 2-8℃ and place it for 30-60 minutes to cool down rapidly, so that the antibacterial expandable microspheres can be cooled and solidified to obtain an antibacterial ultralight shaping paste.

[0072] Example 1

[0073] The first step is to prepare antibacterial expandable microspheres, including the following steps:

[0074] (1.1) Add 0.6 g of expandable microspheres (Korean Dongjin MS140WS type) to 5 mL of 0.9 M silver nitrate solution and mix with magnetic stirring at 600 rpm for 20 min;

[0075] (1.2) The mixture was centrifuged at 3000 rpm for 3 min to separate the precipitate of expandable microspheres with silver ions adsorbed on the surface.

[0076] (1.3) The precipitate was redispersed in 10 mL of deionized water, and then 10 mL of 0.1 M ascorbic acid solution was added and the mixture was stirred magnetically at 600 rpm for 2 h.

[0077] (1.4) The precipitate was separated by centrifugation at 3000 rpm for 3 min and washed three times with deionized water and ethanol respectively. The precipitate was then dried at 30℃ for 48 h to obtain antibacterial expandable microspheres.

[0078] The second step is to prepare the antibacterial ultralight shaping cream, which includes the following steps:

[0079] (2.1) Add 10g of pure acrylic emulsion with a solid content of 55wt%, 0.5g of sodium polyacrylate, 0.1g of alkyl polyoxyethylene ether, 1g of FB-50 type silicone defoamer and 3g of water to a beaker and stir at 300rpm for 30min.

[0080] (2.2) Add 0.1g of antibacterial expandable microspheres, 3g of calcium carbonate and 0.3g of sodium carboxymethyl cellulose and stir at 300rpm for 30min;

[0081] (2.3) Preheat the above mixture at 50°C for 10 min, then stir at 3 rpm for 30 min and heat at 80°C to expand the antibacterial expandable microspheres into antibacterial expandable microspheres. Finally, place the beaker in a 6°C ice water bath for 40 min to cool down quickly, so that the antibacterial expandable microspheres can be cooled and solidified to obtain antibacterial ultralight shaping paste.

[0082] Example 2

[0083] The first step is to prepare antibacterial expandable microspheres, including the following steps:

[0084] (1.1) Add 0.5 g of expandable microspheres (Dongjin MS140WS type from South Korea) to 4 mL of 0.8 M silver nitrate solution and mix with magnetic stirring at 500 rpm for 10 min:

[0085] (1.2) The mixture was centrifuged at 3000 rpm for 3 min to separate the expandable microsphere precipitate with silver ions adsorbed on the surface; (1.3) The precipitate was redispersed in 8 mL of deionized water, and then 8 mL of 0.1 M ascorbic acid solution was added and the mixture was magnetically stirred at 500 rpm for 1 h.

[0086] (1.4) The precipitate was separated by centrifugation at 3000 rpm for 3 min and washed three times with deionized water and ethanol respectively. The precipitate was then dried at 30℃ for 48 h to obtain antibacterial expandable microspheres.

[0087] The second step is to prepare the antibacterial ultralight shaping cream, which includes the following steps:

[0088] (2.1) Add 8g of pure acrylic emulsion with a solid content of 55wt%, 0.3g of sodium polyacrylate, 0.05g of alkyl polyoxyethylene ether, 0.5g of FB-50 type silicone defoamer and 2g of water to a beaker and stir at 300rpm for 20min.

[0089] (2.2) Add 0.05g of antibacterial expandable microspheres, 2g of calcium carbonate and 0.2g of sodium carboxymethyl cellulose and stir at 300rpm for 20min;

[0090] (2.3) Preheat the above mixture at 45°C for 5 minutes, then stir at 300 rpm for 20 minutes and heat at 70°C to expand the antibacterial expandable microspheres into antibacterial expandable microspheres. Finally, place the beaker in a 2°C ice water bath for 30 minutes to cool down quickly and allow the antibacterial expandable microspheres to cool and solidify, thus obtaining an antibacterial ultralight shaping paste.

[0091] Example 3

[0092] The first step is to prepare antibacterial expandable microspheres, including the following steps:

[0093] (1.1) Add 0.7g of expandable microspheres (Dongjin MS140WS type from South Korea) to 6mL of 1.0M silver nitrate solution and mix with magnetic stirring at 700rpm for 20min;

[0094] (1.2) The mixture was centrifuged at 3000 rpm for 3 min to separate the precipitate and obtain expandable microsphere precipitates with silver ions adsorbed on the surface.

[0095] (1.3) The precipitate was redispersed in 12 mL of deionized water, and then 12 mL of 0.2 M ascorbic acid solution was added and mixed with magnetic stirring at 700 rpm for 2 h.

[0096] (1.4) The precipitate was separated by centrifugation at 3000 rpm for 3 min and washed three times with deionized water and ethanol respectively. The precipitate was then dried at 30℃ for 48 h to obtain antibacterial expandable microspheres.

[0097] The second step is to prepare the antibacterial ultralight shaping cream, which includes the following steps:

[0098] (2.1) Add 12g of pure acrylic emulsion with a solid content of 55wt%, 0.7g of sodium polyacrylate, 0.15g of alkyl polyoxyethylene ether, 1.5g of FB-50 type silicone defoamer and 4g of water to a beaker and stir at 300rpm for 40min.

[0099] (2.2) Add 0.15g of antibacterial expandable microspheres, 4g of calcium carbonate and 0.4g of sodium carboxymethyl cellulose and stir at 300rpm for 40min;

[0100] (2.3) Preheat the above mixture at 55°C for 10 min, then stir at 300 rpm for 40 min and heat at 90°C to expand the antibacterial expandable microspheres into antibacterial expandable microspheres. Finally, place the beaker in an 8°C ice water bath for 60 min to cool down quickly, so that the antibacterial expandable microspheres can be cooled and shaped to obtain antibacterial ultralight shaping paste.

[0101] Comparative Example 1

[0102] The first step is to prepare antibacterial expandable microspheres, including the following steps:

[0103] (1.1) Add 0.5g of expandable microspheres (Dongjin MS140WS type from South Korea) to 4mL of 2.0M silver nitrate solution and mix with magnetic stirring at 500rpm for 10min;

[0104] (1.2) The mixture was centrifuged at 3000 rpm for 3 min to separate the precipitate and obtain expandable microsphere precipitates with silver ions adsorbed on the surface.

[0105] (1.3) The precipitate was redispersed in 8 mL of deionized water, and then 12 mL of 0.2 M ascorbic acid solution was added and the mixture was stirred magnetically at 700 rpm for 2 h.

[0106] (1.4) The precipitate was separated by centrifugation at 3000 rpm for 3 min and washed three times with deionized water and ethanol respectively. The precipitate was then dried at 30℃ for 48 h to obtain antibacterial expandable microspheres.

[0107] The second step is to prepare the antibacterial ultralight shaping cream, which includes the following steps:

[0108] (2.1) Add 12g of pure acrylic emulsion with a solid content of 55%, 0.7g of sodium polyacrylate, 0.15g of alkyl polyoxyethylene ether, 1.5g of FB-50 type silicone defoamer and 4g of water to a beaker and stir at 300rpm for 40min.

[0109] (2.2) Add 0.15g of antibacterial expandable microspheres, 4g of calcium carbonate and 0.4g of sodium carboxymethyl cellulose and stir at 300rpm for 40min;

[0110] (2.3) Preheat the above mixture at 55°C for 10 min, then stir at 300 rpm for 40 min and heat at 90°C to expand the antibacterial expandable microspheres into antibacterial expandable microspheres. Finally, place the beaker in an 8°C ice water bath for 60 min to cool down quickly, so that the antibacterial expandable microspheres can be cooled and shaped to obtain antibacterial ultralight shaping paste.

[0111] Performance testing and characterization

[0112] The following data are from tests conducted in Example 1:

[0113] Figure 3 The image shows the FTIR spectrum of the expandable microspheres used in Example 1, where 3414 cm⁻¹ -1 The absorption peak at 2955 cm⁻¹ is the OH bond stretching vibration peak. -1 The absorption peak at 2242 cm⁻¹ is the stretching vibration peak of the CH bond. -1 The absorption peak for the stretching vibration of the C≡N bond is at 1735 cm⁻¹. -1The absorption peak at 1456 cm⁻¹ is the stretching vibration peak of the C=O bond. -1 The absorption peak at 1235 cm⁻¹ is the bending vibration peak of the CH bond. -1 The absorption peak at 1127 cm⁻¹ is the asymmetric stretching vibration peak of the COC bond. -1 The absorption peak at this point is due to the stretching vibration of the CN bond. This indicates that the surface of the expandable microspheres contains a large number of functional groups such as hydroxyl, nitrile, and carbonyl groups, which give it excellent adsorption properties for silver ions.

[0114] Figure 4 The XRD pattern of the antibacterial expandable microspheres obtained in Example 1 is shown in the figure. As can be seen from the figure, the broad peak at 2θ angle of 19.8° is the scattering peak of the amorphous thermoplastic polymer shell. The diffraction peaks at 2θ angles of 38.1°, 44.3°, 64.4° and 77.4° correspond to the (111), (200), (220) and (311) crystal planes of nano-silver (JCPDF 89-3722), respectively. No other impurity peaks are seen in the figure except for the diffraction peaks of nano-silver, indicating that nano-silver was successfully synthesized.

[0115] Figure 5 and Figure 6 The images show SEM images of the expandable microspheres before and after surface modification in Example 1. As can be seen from the images, after surface modification, nano-silver is dispersed on the surface of the expandable microspheres, with a particle size of approximately 60-90 nm.

[0116] Figure 7 This is a SEM image of the antibacterial expandable microspheres after heating and expansion in Example 1. As can be seen from the image, after heating and expansion, the surface of the antibacterial expandable microspheres still has a large number of diffusely distributed silver nanoparticles, indicating that there is a good bonding force between the expandable microsphere shell material and the silver nanoparticles.

[0117] Figure 8 and Figure 9 The images show SEM images of the antibacterial expandable microspheres in Comparative Example 1 before and after heating and expansion. As can be seen from the images, when the silver ion concentration is 2.0 M, silver nanosheets with a size of approximately 350-630 nm are formed on the surface of the microspheres. After heating and expanding the antibacterial expandable microspheres, the number of silver nanosheets on the surface of the generated antibacterial expandable microspheres is significantly reduced, indicating that compared with smaller silver nanoparticles, the silver nanosheets have poorer adhesion to the microsphere surface and detach in large quantities after heating and expansion.

[0118] Figure 10This is a weight comparison chart of the antibacterial ultralight shaping paste and the shaping paste using calcium carbonate filler in Example 1. The antibacterial ultralight shaping paste and the shaping paste using calcium carbonate filler were each prepared into 5cm × 5cm × 1cm test blocks using a mold, and weighed after being completely dried in an oven. The antibacterial ultralight shaping paste weighed 16.1g, and the traditional shaping paste using calcium carbonate filler weighed 31.7g, with a unit weight of 0.644g / cm³, respectively. 3 and 1.268 g / cm 3 Compared to traditional shaping pastes that use calcium carbonate filler, the antibacterial ultralight shaping paste is 50.1% lighter.

[0119] Figure 11 The image shows the effect of antibacterial ultralight shaping cream on canvas. The lines are smooth, the texture is clear, and the highest point of the shape reaches 3.4cm, which has a good shaping effect.

[0120] Figure 12 The figure shows the inhibition zone experiment of the antibacterial ultralight shaping paste. The figure shows the inhibition zone effect of the control group (using calcium carbonate filler) and the antibacterial ultralight shaping pastes of Examples 1, 2, and 3, respectively. The shaping paste using calcium carbonate filler did not show a clear inhibition zone, indicating that the traditional shaping paste using calcium carbonate filler has no antibacterial ability. The antibacterial ultralight shaping pastes of Examples 1, 2, and 3 showed clear inhibition zones with diameters of 12.5 mm, 11.67 mm, and 12.34 mm, respectively. According to the inhibition zone inhibition rate calculation formula in the national standard GB / T 38483-2020:

[0121]

[0122] I—Inhibition rate

[0123] D1—Diameter of the inhibition zone on the sample

[0124] D2—Diameter of blank control

[0125] The inhibition rates of the antibacterial ultralight shaping cream in Examples 1, 2, and 3 were 108.3%, 94.5%, and 105.7%, respectively, indicating that it has a good antibacterial effect.

[0126] Unless otherwise specified, the raw materials and equipment used in this invention are all commonly used in the field; unless otherwise specified, the methods used in this invention are all conventional methods in the field.

[0127] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, alterations, and equivalent transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing an antibacterial ultralight shaping cream, characterized in that: By weight, it includes: (a) Mix 8-12 parts of polymer emulsion, dispersant, wetting agent, defoamer and 2-4 parts of water; (b) Add 0.05-0.15 parts of antibacterial expandable microspheres, 2-4 parts of filler and thickener and stir well; (c) The resulting mixture is preheated at 45-55°C until the thermoplastic polymer shell of the antibacterial expandable microspheres softens, stirred and heated at 70-90°C to expand, and cooled and shaped at 2-8°C. The antibacterial expandable microspheres include: a thermoplastic polymer shell, a volatile expander filling the interior of the thermoplastic polymer shell, and nano-silver with a particle size of 60-90 nm grown in situ on the surface of the thermoplastic polymer shell. The nano-silver is obtained by combining the unbonded lone pairs of electrons on the oxygen and nitrogen atoms of the hydroxyl, carbonyl and nitrile groups on the surface of expandable microspheres with the empty orbitals of silver ions in 0.8-1.0M silver nitrate solution to form coordinate bonds, thereby adsorbing silver ions, and then reducing them; the ratio of expandable microspheres to silver nitrate solution is 0.5-0.7g:4-6mL.

2. The preparation method according to claim 1, characterized in that: The preparation method of the antibacterial expandable microspheres includes the following steps: (1) Mix expandable microspheres with hydroxyl, nitrile and carbonyl groups on the surface with silver salt solution and stir evenly; (2) Centrifuge the mixture obtained in step (1) to obtain expandable microsphere precipitates with silver ions adsorbed on the surface; (3) Redisperse the precipitate obtained in step (2) in water, add a reducing agent and stir to react; (4) The dispersion obtained in step (3) is centrifuged to separate the precipitate, and after washing and drying, antibacterial expandable microspheres are obtained.

3. The preparation method according to claim 2, characterized in that: In step (1), The expandable microspheres are thermoplastic polymer shells filled with volatile expanding agents; The thermoplastic polymer is selected from at least one of polyacrylonitrile, polyacrylates, polyacrylamide, and polyacrylic acid. The volatile expanding agent is selected from one or more of n-pentane, isopentane, neopentane, butane, and isobutane.

4. The preparation method according to claim 2, characterized in that: In step (3), The reducing agent is an ascorbic acid solution with a concentration of 0.1-0.2M; The ratio of water to ascorbic acid solution is 8-12 mL: 8-12 mL.

5. The preparation method according to claim 1 or 2, characterized in that: The polymer emulsion is selected from one or more of pure acrylic emulsion, silicone acrylic emulsion, and styrene acrylic emulsion, and has a solid content of 50-60 wt%.

6. The preparation method according to claim 1 or 2, characterized in that: The filler is calcium carbonate.

7. The preparation method according to claim 1 or 2, characterized in that: The dispersant is 0.3-0.7 parts by weight, the wetting agent is 0.05-0.15 parts by weight, the defoamer is 0.5-1.5 parts by weight, and the thickener is 0.2-0.4 parts by weight.

8. The preparation method according to claim 1, characterized in that: The dispersant is selected from one or more of sodium tripolyphosphate, sodium hexametaphosphate and sodium pyrophosphate, triethylhexyl phosphate, sodium dodecyl sulfate, methyl pentanol, cellulose derivatives, sodium polyacrylate, glucon, fatty acid polyethylene glycol esters and polyethers; The wetting agent is selected from one or more of alkyl polyoxyethylene ethers, polyether silicones, and nonionic fluorocarbon polymers. The defoamer is selected from one or more of the following: organosilicon compounds, mineral oils, polyethers, and high-carbon alcohols with 7-9 carbon atoms; The thickener is selected from one or more of sodium methylcellulose, polyacrylate, and associative polyurethane.

9. The preparation method according to claim 1, characterized in that: In steps (a)-(c), the stirring speed is 300-500 rpm and the time is 20-40 min.

10. The preparation method according to claim 1, characterized in that: In step (c), the preheating temperature is 45-55℃ and the time is 5-10 min; the stirring speed is 300-500 rpm and the time is 20-40 min; the heating temperature is 70-90℃; and the cooling is performed using an ice-water bath at a temperature of 2-8℃ for 30-60 min.

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