Cerium oxide antibacterial and antioxidant soap and preparation method thereof

Abstract

The application discloses cerium oxide antibacterial and antioxidative soap and a preparation method thereof, and belongs to the technical field of daily chemical products. The cerium oxide antibacterial and antioxidative soap is prepared from the following raw materials: a natural plant soap base, composite nano cerium oxide, a moisturizing agent, a pH regulator and natural essence. The composite nano cerium oxide is obtained by loading nano cerium oxide on amphiphilic hyaluronic acid. The amphiphilic hyaluronic acid is obtained by reacting hyaluronic acid with aminated vitamin E. The aminated vitamin E is obtained by reacting tocopherol succinate with ethylenediamine. The nano cerium oxide has a particle size of 50-200 nm, a purity of greater than or equal to 99.9%, and a heavy metal content of less than or equal to 1 ppm. The addition amount of the composite nano cerium oxide is 0.5-2.0 wt%. The cerium oxide antibacterial and antioxidative soap prepared by the application has good antibacterial, antioxidative, moisturizing and stain-removing effects.

Description

Technical Field

[0001] This invention relates to the field of daily chemical products technology, specifically to a cerium oxide antibacterial and antioxidant soap and its preparation method. Background Technology

[0002] Soap, a long-established and widely used daily cleaning product, primarily functions to remove dirt, oil, and attached microorganisms from the skin's surface through the physicochemical action of surfactants. However, with rising living standards and increased health awareness, the single function of traditional soap—basic cleaning and stain removal—is no longer sufficient to meet the high standards of modern consumers for personal care products. Especially in the humid bathroom environment, traditional soap easily absorbs moisture and softens, becoming a breeding ground for bacteria. This not only leads to the soap's own spoilage but may also cause cross-infection during secondary use, posing significant health risks.

[0003] To overcome the drawback of traditional soaps being prone to bacterial growth, various antibacterial soaps have emerged in existing technologies. Most antibacterial soaps on the market currently achieve their antibacterial function by adding organic antibacterial agents such as triclocarban and triclosan, or inorganic antibacterial agents such as silver ions and zinc ions. However, these existing antibacterial technologies still have many limitations in practical applications. On the one hand, long-term use of some organic antibacterial agents can easily induce bacterial resistance and has a certain degree of irritation to the skin and mucous membranes, raising concerns about their safety. On the other hand, while metallic antibacterial agents, represented by silver ions, have good antibacterial effects, they suffer from chemical instability, are easily affected by light or environmental factors leading to discoloration and precipitation, and can damage the appearance of the soap. Furthermore, their production costs are relatively high.

[0004] Furthermore, the complex modern living environment, with its air pollution and ultraviolet radiation, generates a large number of free radicals on the skin's surface. During daily cleansing, if soap focuses solely on removing dirt while neglecting antioxidant protection, its strong cleansing action often damages the skin's lipid barrier, exacerbating oxidative damage from free radicals and leading to dryness, roughness, and a weakened skin barrier. Therefore, developing a soap product that is both highly effective at antibacterial action and at eliminating free radicals and repairing the skin is particularly important.

[0005] In recent years, cerium oxide nanomaterials, as a rare earth nanomaterial, have attracted much attention due to their unique physicochemical properties. The surface of cerium oxide nanomaterials possesses abundant oxygen vacancies, exhibiting unique nanoenzyme activity and Ce... 3+ / Ce 4+Reversible redox cycle properties. This characteristic allows it to mimic the action of superoxide dismutase and catalase, achieving not only broad-spectrum and potent antibacterial effects but also minimizing the likelihood of drug resistance. Simultaneously, it effectively scavenge reactive oxygen free radicals on the skin surface, exhibiting excellent antioxidant and skin-repairing effects. Furthermore, nano-cerium oxide is chemically stable, safe, and mild, making it a highly promising functional additive.

[0006] Despite the aforementioned superior properties of nano-cerium oxide, its direct application in soap making still faces significant technical challenges. Due to their extremely small size, large specific surface area, and high surface energy, nano-cerium oxide particles exhibit a strong tendency to aggregate. If directly added to soap base, the nanoparticles readily aggregate, forming large micron-sized particles. This not only results in a rough soap texture and affects the feel on the skin, but also significantly reduces the specific surface area, leading to a decrease in antibacterial and antioxidant active sites, a substantial decline in performance, and an inability to exert the intended effects of nanomaterials.

[0007] In summary, overcoming the agglomeration problem of nano-cerium oxide in soap base and achieving its uniform and stable dispersion in soap system, thereby preparing a multifunctional soap with super antibacterial, long-lasting antioxidant and gentle skin care properties, is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0008] The purpose of this invention is to provide a cerium oxide antibacterial and antioxidant soap and its preparation method, so as to solve the technical problems mentioned in the background art.

[0009] The technical solution to achieve the objective of this invention is: In a first aspect, the present invention provides a cerium oxide antibacterial and antioxidant soap, the raw material components of which include natural plant soap base, composite nano cerium oxide, moisturizer, pH adjuster, and natural fragrance; the amount of composite nano cerium oxide added is 0.5~2.0wt%.

[0010] Furthermore, the composite nano-cerium oxide is obtained by loading nano-cerium oxide with amphiphilic hyaluronic acid.

[0011] Furthermore, the amphiphilic hyaluronic acid is obtained by reacting hyaluronic acid with aminolated vitamin E.

[0012] Furthermore, the aminoated vitamin E is obtained by reacting tocopherol succinic acid with ethylenediamine.

[0013] Furthermore, the nano-cerium oxide particles have a diameter of 50~200nm, a purity of ≥99.9%, and a heavy metal content of ≤1ppm.

[0014] Secondly, the present invention provides a method for preparing cerium oxide antibacterial and antioxidant soap as described in the first aspect, comprising the following steps: (1) Weigh and mix each raw material component: (2) The composite nano-cerium oxide was dispersed in deionized water and homogenized for 10-15 min at 10000-12000 r / min using a high-speed homogenizer, and then ultrasonically dispersed for 5-10 min to obtain dispersion A; (3) Chop the natural plant soap base and place it in a reaction vessel and heat it to 55~65℃ to melt it. Stir it at low speed until it is transparent and uniform to obtain molten soap base; (4) Cool the molten soap base to 45~55℃, slowly add dispersion A, and continue stirring for 8~12 minutes. Then add humectant and pH adjuster, and continue stirring for 5~8 minutes. Next, add natural fragrance, stir for 2~3 minutes, and let stand for 5~10 minutes to defoam. (5) Pour the soap solution into the mold, gently shake to release the air, keep it warm and solidified at 35~40℃ for 24 hours, then demold and place it in a cool and ventilated place to mature for 3~4 weeks.

[0015] Furthermore, the raw material components, by mass fraction, include 90-95 wt% natural plant soap base, 0.5-2 wt% composite nano cerium oxide, 2-4 wt% moisturizer, 0.3-0.8 wt% pH adjuster, 0.1-0.3 wt% natural fragrance, and 4-8 wt% deionized water.

[0016] Furthermore, the pH of the cerium oxide antibacterial and antioxidant soap is 8 to 8.5.

[0017] Furthermore, the preparation steps of the composite nano-cerium oxide are as follows: 0.05~0.1 parts by mass of amphiphilic hyaluronic acid are dispersed in 25~50 parts by mass of deionized water, 0.6~1.2 parts by mass of nano-cerium oxide are added, homogenized at 22000 rpm for 5 min, and then freeze-dried to obtain composite nano-cerium oxide.

[0018] Furthermore, the preparation steps of the amphiphilic hyaluronic acid are as follows: A1. Weigh 0.4 parts by weight of D-α-tocopherol succinate and mix with 13.2-13.3 parts by weight of dichloromethane until dissolved. Then add 0.086 parts by weight of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and 0.052 parts by weight of N-hydroxysuccinimide. Stir for 2 hours under ice bath conditions. Then add dropwise to 1.34-1.36 parts by weight of ethylenediamine and stir for 2-4 hours. Then extract with a mixture of dichloroethane and distilled water at least 6 times. Then take the lower extract, add 2 ml of dichloromethane, and evaporate at 40°C to obtain aminoated vitamin E. A2. Dissolve 0.08-0.1 parts by weight of hyaluronic acid in 10 parts by weight of deionized water, then add 0.086 parts by weight of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and 0.052 parts by weight of N-hydroxysuccinimide. React under ice bath conditions for 4-6 hours, then add dropwise 6.625 parts by weight of dichloromethane solution containing 0.6-0.72 parts by weight of amino-modified vitamin E. Continue stirring at 58-62°C for 4-6 hours, then stir at room temperature for 23-24 hours. Next, filter to remove insoluble white impurities. Place the reaction solution into a dialysis bag with a capacity cutoff of 3500 Da, and dialyze it sequentially in a water / ethanol mixture with a volume ratio of 7:3, 5:5, 3:7 for 1 day, then dialyze it in deionized water for 2 days. Finally, filter it through a 0.45 μm filter membrane and freeze-dry it to obtain amphiphilic hyaluronic acid.

[0019] By adopting the above technical solution, the present invention has the following beneficial effects: The cerium oxide antibacterial and antioxidant soap of the present invention comprises natural plant soap base, composite nano-cerium oxide, moisturizer, pH adjuster, and natural fragrance. The amount of composite nano-cerium oxide added is 0.5~2.0wt%. The composite nano-cerium oxide is obtained by loading nano-cerium oxide with amphiphilic hyaluronic acid. The amphiphilic hyaluronic acid is obtained by reacting hyaluronic acid with aminoated vitamin E. The aminoated vitamin E is obtained by reacting tocopheryl succinic acid with ethylenediamine. This invention overcomes the problem of nano-cerium oxide agglomeration in the soap base. The resulting cerium oxide antibacterial and antioxidant soap can effectively fight bacteria, eliminate free radicals, and repair the skin.

[0020] The cerium oxide antibacterial and antioxidant soap of the present invention introduces composite cerium oxide obtained by loading nano-cerium oxide with amphiphilic hyaluronic acid. The amphiphilic hyaluronic acid molecular chain possesses both hydrophilic and hydrophobic groups, enabling it to act as a natural stabilizing medium and generate strong interfacial interactions with the nano-cerium oxide. During the preparation process, the amphiphilic hyaluronic acid spontaneously adsorbs and anchors to the surface of the nano-cerium oxide particles. Utilizing the steric hindrance effect of its hydrophobic molecular chain and the interfacial compatibility brought by its amphiphilic structure, it effectively overcomes the van der Waals attraction caused by the high surface energy of the nanoparticles, thereby preventing the aggregation tendency between particles at the microscopic level. This allows the nano-cerium oxide to achieve a highly uniform and stable dispersion in the soap matrix without relying on additional chemical dispersants or surfactants. This avoids the safety risks that external additives may bring and maximizes the preservation of the active sites of the nano-cerium oxide, ensuring the antibacterial and antioxidant efficacy of the finished soap.

[0021] The amphiphilic hyaluronic acid of this invention uses tocopheryl succinate as a starting material, which reacts with ethylenediamine to form an amide bond, thereby successfully introducing an amino group into the molecular structure to obtain aminoated vitamin E. Subsequently, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide are used as condensing agents and activators to activate the carboxyl groups on the hyaluronic acid molecular chain, causing it to undergo an efficient amidation reaction with the vitamin E derivative containing an amino group. Finally, an amphiphilic hyaluronic acid with both hydrophilic and hydrophobic properties is successfully synthesized. Not only does the unique amphiphilic structure of the amphiphilic hyaluronic acid serve as an excellent dispersion medium, effectively achieving uniform and stable loading of nano-cerium oxide, but it also perfectly preserves the excellent moisturizing and skin care properties of hyaluronic acid and vitamin E, thereby significantly improving the overall efficacy of the soap product.

[0022] The cerium oxide antibacterial and antioxidant soap of this invention exhibits excellent antibacterial properties, with an antibacterial rate of 99% or higher against various common pathogens, possessing broad-spectrum and long-lasting antibacterial advantages. Simultaneously, this soap combines highly effective antioxidant and skin-repairing functions, achieving simultaneous skin care during daily cleansing. Furthermore, thanks to the uniform and stable dispersion of the core ingredient, nano-cerium oxide, in the soap body, the product fundamentally eliminates particle agglomeration and soap discoloration problems, exhibiting good physicochemical stability. The soap is weakly alkaline, providing powerful cleansing without damaging the human skin barrier, thus making it suitable for a wide range of people. In addition, the preparation process of this invention is simple and the parameters are highly controllable, well adaptable to the needs of large-scale industrial mass production. Detailed Implementation

[0023] To better understand the above technical solution, the following will provide a detailed explanation of the technical solution in conjunction with specific implementation methods.

[0024] Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention.

[0025] The following embodiments are only used to illustrate the technical solutions of the present invention more clearly, and should not be used to limit the scope of protection of the present invention.

[0026] Hyaluronic acid with a molecular weight of 5300 Da. Shandong Freda Biomedical Co., Ltd.

[0027] The nano-cerium oxide has an average particle size of 100 nm and a purity of ≥99.9%. Example 1 A method for preparing a cerium oxide antibacterial and antioxidant soap, comprising the following steps: (1) Weigh and mix the raw materials: 31 parts sodium laurylate, 31 parts sodium myristate, 31 parts sodium cocoate, 0.5 parts composite nano cerium oxide, 3 parts moisturizing agent glycerin, sodium citrate to adjust pH to 8, 0.3 parts natural fragrance, and the remainder is deionized water; (2) The composite nano-cerium oxide was dispersed in deionized water and homogenized for 15 min at 10000 r / min using a high-speed homogenizer, and then ultrasonically dispersed for 10 min to obtain dispersion A; (3) Chop the natural plant soap base and place it in a reaction vessel and heat it to 55°C to melt it. Stir it at low speed until it is transparent and uniform to obtain molten soap base; (4) Cool the molten soap base to 45°C, slowly add dispersion A, and continue stirring for 12 minutes. Then add humectant and pH adjuster, and continue stirring for 8 minutes. Next, add natural fragrance, stir for 3 minutes, and let stand for 10 minutes to defoam. (5) Pour the soap liquid into the mold, gently shake to release the air, keep it warm and solidified at 35°C for 24 hours, then demold and place it in a cool and ventilated place to mature for 3 weeks.

[0028] The preparation steps of the composite nano-cerium oxide are as follows: 0.05 parts by mass of amphiphilic hyaluronic acid are dispersed in 25 parts by mass of deionized water, 0.6 parts by mass of nano-cerium oxide are added, homogenized at 22000 rpm for 5 min, and then freeze-dried to obtain composite nano-cerium oxide.

[0029] The preparation steps of the amphiphilic hyaluronic acid are as follows: A1. Weigh 0.4 parts by weight of D-α-tocopherol succinate and mix with 13.2 parts by weight of dichloromethane until dissolved. Then add 0.086 parts by weight of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and 0.052 parts by weight of N-hydroxysuccinimide. Stir for 2 hours under ice bath conditions. Then add dropwise to 1.34 parts by weight of ethylenediamine and stir for 2 hours. Then extract 6 times with a mixture of dichloroethane and distilled water. Then take the lower extract, add 2 ml of dichloromethane, and evaporate at 40°C to obtain aminoated vitamin E. A2. Dissolve 0.08 parts by mass of hyaluronic acid in 10 parts by mass of deionized water, then add 0.086 parts by mass of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and 0.052 parts by mass of N-hydroxysuccinimide. React under ice bath conditions for 4 hours, then add dropwise 6.625 parts by mass of dichloromethane solution containing 0.6 parts by mass of amino-modified vitamin E. Continue stirring at 58°C for 6 hours, then stir at room temperature for 23 hours. Next, filter to remove insoluble white impurities. Place the reaction solution into a dialysis bag with a capacity cutoff of 3500 Da, and dialyze it sequentially in a water / ethanol mixture with a volume ratio of 7:3, 5:5, 3:7 for 1 day, then dialyze it in deionized water for 2 days. Finally, filter it through a 0.45 μm filter membrane and freeze-dry to obtain amphiphilic hyaluronic acid.

[0030] Example 2 A method for preparing a cerium oxide antibacterial and antioxidant soap, comprising the following steps: (1) Weigh and mix the raw materials: 31 parts sodium laurylate, 31 parts sodium myristate, 31 parts sodium cocoate, 1.3 parts composite nano cerium oxide, 3 parts moisturizing agent glycerin, sodium citrate to adjust pH to 8, 0.3 parts natural fragrance, and the remainder is deionized water; (2) The composite nano-cerium oxide was dispersed in deionized water and homogenized for 15 min at 12000 r / min using a high-speed homogenizer, and then ultrasonically dispersed for 5 min to obtain dispersion A; (3) Chop the natural plant soap base and place it in a reaction vessel and heat it to 60°C to melt it. Stir it at low speed until it is transparent and uniform to obtain molten soap base; (4) Cool the molten soap base to 50°C, slowly add dispersion A, and continue stirring for 10 minutes. Then add humectant and pH adjuster, and continue stirring for 6 minutes. Next, add natural fragrance, stir for 3 minutes, and let stand for 10 minutes to defoam. (5) Pour the soap solution into the mold, gently shake to release the air, keep it warm and solid at 38°C for 24 hours, then demold and place it in a cool and ventilated place to mature for 4 weeks.

[0031] The preparation steps of the composite nano-cerium oxide are as follows: 0.08 parts by mass of amphiphilic hyaluronic acid are dispersed in 25 parts by mass of deionized water, 0.8 parts by mass of nano-cerium oxide are added and homogenized at 22000 rpm for 5 min, and then freeze-dried to obtain composite nano-cerium oxide.

[0032] The preparation steps of the amphiphilic hyaluronic acid are as follows: A1. Weigh 0.4 parts by weight of D-α-tocopherol succinate and mix with 13.25 parts by weight of dichloromethane until dissolved. Then add 0.086 parts by weight of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and 0.052 parts by weight of N-hydroxysuccinimide. Stir for 2 hours under ice bath conditions, then add dropwise to 1.35 parts by weight of ethylenediamine. Stir and react for 3 hours. Then extract 6 times with a mixture of dichloroethane and distilled water. Take the lower extract, add 2 ml of dichloromethane, and evaporate at 40°C to obtain aminoated vitamin E. A2. Dissolve 0.09 parts by weight of hyaluronic acid in 10 parts by weight of deionized water, then add 0.086 parts by weight of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and 0.052 parts by weight of N-hydroxysuccinimide. After reacting for 5 hours under ice bath conditions, add dropwise 6.625 parts by weight of dichloromethane solution containing 0.66 parts by weight of amino-modified vitamin E. Continue stirring at 60°C for 5 hours, then stir at room temperature for 24 hours. Next, filter to remove insoluble white impurities. Place the reaction solution into a dialysis bag with a capacity cutoff of 3500 Da and dialyze it sequentially in a water / ethanol mixture with a volume ratio of 7:3, 5:5, 3:7 for 1 day, then dialyze it in deionized water for 2 days. Finally, filter it through a 0.45 μm filter membrane and freeze-dry it to obtain amphiphilic hyaluronic acid.

[0033] Example 3 A method for preparing a cerium oxide antibacterial and antioxidant soap, comprising the following steps: (1) Weigh and mix the raw materials: 31 parts sodium laurylate, 31 parts sodium myristate, 31 parts sodium cocoate, 2 parts composite nano cerium oxide, 3 parts moisturizing agent glycerin, sodium citrate to adjust pH to 8.5, 0.3 parts natural fragrance, and the remainder is deionized water; (2) The composite nano-cerium oxide was dispersed in deionized water and homogenized for 15 min at 12000 r / min using a high-speed homogenizer, and then ultrasonically dispersed for 5 min to obtain dispersion A; (3) Chop the natural plant soap base and place it in a reaction vessel and heat it to 65°C to melt it. Stir it at low speed until it is transparent and uniform to obtain molten soap base; (4) Cool the molten soap base to 55°C, slowly add dispersion A, and continue stirring for 8 minutes. Then add humectant and pH adjuster, and continue stirring for 5 minutes. Next, add natural fragrance, stir for 2 minutes, and let stand for 5 minutes to defoam. (5) Pour the soap solution into the mold, gently shake to release air, keep it warm and solidify at 40℃ for 24 hours, then demold and place it in a cool and ventilated place to mature for 4 weeks.

[0034] The preparation steps of the composite nano-cerium oxide are as follows: 0.1 parts by mass of amphiphilic hyaluronic acid are dispersed in 50 parts by mass of deionized water, 1.2 parts by mass of nano-cerium oxide are added, homogenized at 22000 rpm for 5 min, and then freeze-dried to obtain composite nano-cerium oxide.

[0035] The preparation steps of the amphiphilic hyaluronic acid are as follows: A1. Weigh 0.4 parts by weight of D-α-tocopherol succinate and mix with 13.3 parts by weight of dichloromethane until dissolved. Then add 0.086 parts by weight of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and 0.052 parts by weight of N-hydroxysuccinimide. Stir for 2 hours under ice bath conditions. Then add dropwise to 1.36 parts by weight of ethylenediamine and stir for 4 hours. Then extract 6 times with a mixture of dichloroethane and distilled water. Then take the lower extract, add 2 ml of dichloromethane, and evaporate at 40°C to obtain aminoated vitamin E. A2. Dissolve 0.1 parts by mass of hyaluronic acid in 10 parts by mass of deionized water, then add 0.086 parts by mass of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and 0.052 parts by mass of N-hydroxysuccinimide. After reacting for 6 hours under ice bath conditions, add dropwise 6.625 parts by mass of dichloromethane solution containing 0.72 parts by mass of amino-modified vitamin E. Continue stirring at 62°C for 4 hours, then stir at room temperature for 24 hours. Next, filter to remove insoluble white impurities. Place the reaction solution into a dialysis bag with a capacity cutoff of 3500 Da and dialyze it sequentially in a water / ethanol mixture with a volume ratio of 7:3, 5:5, 3:7 for 1 day, then dialyze it in deionized water for 2 days. Finally, filter it through a 0.45 μm filter membrane and freeze-dry it to obtain amphiphilic hyaluronic acid.

[0036] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is the composition. The raw material composition is: 31 parts sodium laurylate, 31 parts sodium myristate, 31 parts sodium cocoate, 1 part nano cerium oxide, 0.3 parts coconut oil fatty acid monoethanolamide, 3 parts glycerin (moisturizer), sodium citrate to adjust the pH to 8, 0.3 parts natural fragrance, and the balance is deionized water.

[0037] Blank example The only difference between the blank example and Example 1 is the composition. The raw material composition is: 31 parts sodium laurate, 31 parts sodium myristate, 31 parts sodium cocoate, 1 part nano cerium oxide, 3 parts glycerin (moisturizer), sodium citrate to adjust the pH to 8, 0.3 parts natural fragrance, and the remainder is deionized water.

[0038] Example of effect Antibacterial test: The antibacterial effect of the cerium oxide antibacterial and antioxidant soap prepared in this invention was tested according to the QB / T 2738 suspension quantitative method. The test concentration was 1:100, the action time was 20 min, and the test bacteria were Staphylococcus aureus ATCC 6538, Escherichia coli 8099 and Candida albicans ATCC 14053.

[0039] Table 1 below shows the antibacterial performance test results of the cerium oxide antibacterial and antioxidant soaps prepared in Examples 1-3 and Comparative Example 1: Table 1

[0040] Table 1 shows that the antibacterial and antioxidant soaps prepared by cerium oxide in Examples 1-3 and Comparative Example 1 all had an inhibition rate of more than 99% against Staphylococcus aureus, Escherichia coli and Candida albicans, indicating that the addition of cerium oxide can significantly improve the antibacterial properties of the soap.

[0041] Cleansing and skin care tests: Skin irritation tests were conducted on the cerium oxide antibacterial and antioxidant soaps prepared in Examples 1-3 and Comparative Example 1, respectively. Specifically, when the concentration of the soap solution used in the experiment was 5 wt% and the amount used was 0.3 mL, the skin reaction grading, i.e., the relative irritation value grading, was determined by the HETVAM test: strong irritation >2.0, irritation 1.2-2.0, moderate irritation 0.8-1.2, and mild irritation 0-0.8. The skin moisture content before washing and the skin moisture content 2 hours after washing were measured using a moisture meter, and the percentage increase in skin moisture content was calculated. The cleaning power of the soap was tested using a standardized 10-minute wiping method. A surface with stains was selected for cleaning, and the cleaning effect after each wiping was recorded to evaluate the stain removal rate of the soap. The smoothness of the surface of the cerium oxide antibacterial and antioxidant soaps prepared in Examples 1-3 and Comparative Example 1 was observed by visual inspection.

[0042] Table 2 below shows the performance test results of the cerium oxide antibacterial and antioxidant soaps prepared in Examples 1-3 and Comparative Example 1: Table 2

[0043] Table 2 shows that the cerium oxide antibacterial and antioxidant soaps prepared in Examples 1-3 have a smooth appearance and good cleaning power and moisturizing effect.

[0044] The difference between Comparative Example 1 and the Examples is that a dispersant was added to disperse the nano-cerium oxide instead of using composite nano-cerium oxide. The comparison shows that the soaps of Examples 1-3 using composite nano-cerium oxide and the soaps with added dispersant both have a smooth appearance, indicating that the dispersibility of composite nano-cerium oxide can achieve the same effect as adding a dispersant without adding a dispersant; and the cleaning power is not affected, the moisturizing effect is better, and the irritation is lower.

[0045] The blank sample did not contain any dispersant or composite nano-cerium oxide. In particular, the soap body exhibited a noticeably rough texture. This was mainly due to the severe agglomeration of nano-cerium oxide particles in the absence of effective dispersion methods, which damaged the fineness of the soap base. This physical roughness caused by particle agglomeration would generate greater mechanical friction on the skin during cleansing, thus directly leading to a significant increase in the irritation level of this group of soaps.

[0046] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A cerium oxide antibacterial and antioxidant soap, characterized in that, The raw material components include natural plant soap base, composite nano cerium oxide, moisturizer, pH adjuster, and natural fragrance; the amount of composite nano cerium oxide added is 0.5~2.0wt%.

2. The cerium oxide antibacterial and antioxidant soap according to claim 1, characterized in that, The composite nano-cerium oxide is obtained by loading nano-cerium oxide with amphiphilic hyaluronic acid.

3. The cerium oxide antibacterial and antioxidant soap according to claim 2, characterized in that, The amphiphilic hyaluronic acid is obtained by reacting hyaluronic acid with amino-modified vitamin E.

4. The cerium oxide antibacterial and antioxidant soap according to claim 3, characterized in that, The aminoated vitamin E is obtained by reacting tocopherol succinic acid with ethylenediamine.

5. The cerium oxide antibacterial and antioxidant soap according to claim 2, characterized in that, The nano-cerium oxide particles have a diameter of 50~200nm, a purity of ≥99.9%, and a heavy metal content of ≤1ppm.

6. A method for preparing a cerium oxide antibacterial and antioxidant soap as described in any one of claims 1 to 5, characterized in that, The steps are as follows: (1) Weigh and mix each raw material component: (2) The composite nano-cerium oxide was dispersed in deionized water and homogenized for 10-15 min at 10000-12000 r / min using a high-speed homogenizer, and then ultrasonically dispersed for 5-10 min to obtain dispersion A; (3) Chop the natural plant soap base and place it in a reaction vessel and heat it to 55~65℃ to melt it. Stir it at low speed until it is transparent and uniform to obtain molten soap base; (4) Cool the molten soap base to 45~55℃, slowly add dispersion A, and continue stirring for 8~12 minutes. Then add humectant and pH adjuster, and continue stirring for 5~8 minutes. Next, add natural fragrance, stir for 2~3 minutes, and let stand for 5~10 minutes to defoam. (5) Pour the soap solution into the mold, gently shake to release the air, keep it warm and solidified at 35~40℃ for 24 hours, then demold and place it in a cool and ventilated place to mature for 3~4 weeks.

7. The method for preparing cerium oxide antibacterial and antioxidant soap according to claim 6, characterized in that, The raw material components, by mass fraction, include 90-95 wt% natural plant soap base, 0.5-2 wt% composite nano cerium oxide, 2-4 wt% humectant, 0.3-0.8 wt% pH adjuster, 0.1-0.3 wt% natural fragrance, and 4-8 wt% deionized water.

8. The method for preparing cerium oxide antibacterial and antioxidant soap according to claim 6, characterized in that, The pH of the cerium oxide antibacterial and antioxidant soap is 8-8.

5.

9. The method for preparing cerium oxide antibacterial and antioxidant soap according to claim 6, characterized in that, The preparation steps of the composite nano-cerium oxide are as follows: Take 0.05~0.1 parts by mass of amphiphilic hyaluronic acid and disperse it in 25~50 parts by mass of deionized water, add 0.6~1.2 parts by mass of nano-cerium oxide, homogenize at 22000 rpm for 5 min, and then freeze dry to obtain composite nano-cerium oxide.

10. The method for preparing cerium oxide antibacterial and antioxidant soap according to claim 9, characterized in that, The preparation steps of the amphiphilic hyaluronic acid are as follows: A1. Weigh 0.4 parts by weight of D-α-tocopherol succinate and mix with 13.2-13.3 parts by weight of dichloromethane until dissolved. Then add 0.086 parts by weight of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and 0.052 parts by weight of N-hydroxysuccinimide. Stir for 2 hours under ice bath conditions. Then add dropwise to 1.34-1.36 parts by weight of ethylenediamine and stir for 2-4 hours. Then extract with a mixture of dichloroethane and distilled water at least 6 times. Then take the lower extract, add 2 ml of dichloromethane, and evaporate at 40°C to obtain aminoated vitamin E. A2. Dissolve 0.08-0.1 parts by weight of hyaluronic acid in 10 parts by weight of deionized water, then add 0.086 parts by weight of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and 0.052 parts by weight of N-hydroxysuccinimide. React under ice bath conditions for 4-6 hours, then add dropwise 6.625 parts by weight of dichloromethane solution containing 0.6-0.72 parts by weight of amino-modified vitamin E. Continue stirring at 58-62°C for 4-6 hours, then stir at room temperature for 23-24 hours. Next, filter to remove insoluble white impurities. Place the reaction solution into a dialysis bag with a capacity cutoff of 3500 Da, and dialyze it sequentially in a water / ethanol mixture with a volume ratio of 7:3, 5:5, 3:7 for 1 day, then dialyze it in deionized water for 2 days. Finally, filter it through a 0.45 μm filter membrane and freeze-dry it to obtain amphiphilic hyaluronic acid.

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