Whitening cosmetic and preparation method thereof

Abstract

The invention discloses a whitening cosmetic and a preparation method thereof, and relates to the technical field of cosmetics. Through a two-step emulsification method, the whitening agent and the polyglycerol polyricinoleate are prepared into the colostrum, so that the stability of the colostrum is improved, and the dual effects of cleaning and skin care are realized; and forming a multiple emulsion system with an external water phase to improve the overall performance. According to the whitening agent, kaolin is used as a raw material, gamma-glycidyl ether oxypropyl trimethoxy silane is firstly used for modifying kaolin, and the dispersity, the adsorption capacity and the compatibility are improved; then, under the action of a bridging agent, the chitosan is combined with aspartic acid to form a stable three-dimensional network structure, a structure similar to a protective film can be formed on the skin surface, meanwhile, moisture and nutrient substances in the skin can be maintained, the moisturizing and anti-oxidation effects are achieved, and on the basis, aspartic acid has the acid-base buffering capacity, inhibits growth of harmful microorganisms, and has the anti-oxidation effect on the skin. The antibacterial and moisturizing functions are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of cosmetics, in particular to a whitening cosmetic and a preparation method thereof. Background Art

[0002] In today's era of pursuit of beauty, the whitening cosmetics market continues to flourish. Consumers' expectations for whitening products are no longer limited to simple whitening effects, but pay more attention to the comprehensive performance of the products. However, when designing the formula of most whitening cosmetics, they often focus on the addition of whitening ingredients and ignore the consideration of skin moisturizing. After using these whitening products, the skin loses moisture quickly and it is difficult to keep it moisturized for a long time. This not only affects the gloss and elasticity of the skin, but may also cause fine lines and desquamation due to dryness, reducing the user experience.

[0003] At the same time, since cosmetics are easily contaminated by microorganisms during use, it is necessary to have a certain antibacterial ability. However, many whitening cosmetics currently lack effective antibacterial mechanisms. After opening and using, they are prone to breed bacteria, mold and other microorganisms, which will not only affect the quality and safety of the products, but may also cause adverse consequences such as skin allergies and infections, posing a potential threat to consumers' health. In addition, the chemical properties of whitening ingredients are often more active. Under the influence of environmental factors such as light and temperature changes, they are prone to decomposition, oxidation and other reactions, which greatly reduces the whitening effect. At the same time, compatibility issues between the ingredients in the product formula may also cause stratification, precipitation and other phenomena during storage, which greatly affects the appearance and use of the product and increases the cost and risk in the production and sales process. Summary of the invention

[0004] The object of the present invention is to provide a whitening cosmetic and a preparation method thereof to solve the problems existing in the prior art.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a whitening cosmetic, wherein a whitening agent and polyglycerol polyricinoleate are first prepared into colostrum, and then a multiple emulsion system is formed with an external water phase; the whitening agent is prepared by modifying kaolin with γ-glycidyloxypropyltrimethoxysilane, and then reacting and combining with aspartic acid under the action of a bridging agent.

[0006] Furthermore, a method for preparing a whitening cosmetic comprises the following preparation steps:

[0007] (1) 5 to 15 parts of kaolin are uniformly dispersed in 60 to 150 parts of anhydrous ethanol, the temperature is raised to 55 to 65° C., 3 to 11 parts of γ-glycidyloxypropyltrimethoxysilane hydrolyzate are added dropwise, the mixture is stirred at 100 rpm for 4 to 6 hours, the mixture is naturally cooled to room temperature, the mixture is transferred to a centrifuge and centrifuged at 3000 rpm for 5 to 15 minutes, the solid is collected, the solid is washed twice with ethanol and deionized water alternately, and the solid is dried at 50 to 60° C. for 10 to 16 hours to obtain modified kaolin;

[0008] (2) Under a nitrogen atmosphere, 6 to 10 parts of modified kaolin are dispersed in 80 to 120 parts of deionized water, 3 to 5 parts of aspartic acid are added, and the mixture is stirred at 100 rpm for 24 to 36 hours, then the temperature is raised to 60 to 70° C., and the reaction is continued for 32 to 60 hours. After the reaction is completed, the solid is filtered and collected, washed with deionized water for 3 times, and dried in an oven at 25 to 35° C. for 16 to 24 hours to obtain a whitening agent;

[0009] (3) evenly dispersing 5 to 15 parts of a whitening agent in 20 to 40 parts of deionized water, adding 30 to 50 parts of the oil phase mixture, rapidly stirring and emulsifying at 30 to 40° C. and 1000 rpm for 20 to 30 minutes, and naturally cooling to room temperature to obtain colostrum;

[0010] (4) Add 30 to 50 parts of the external aqueous phase mixture to the colostrum prepared in step (3) under stirring at 1000 rpm, and mix for 10 to 20 minutes to prepare a whitening cosmetic.

[0011] Furthermore, the dripping rate in step (1) is 2 mL / min.

[0012] Furthermore, the preparation steps of the γ-glycidyloxypropyltrimethoxysilane hydrolyzate in step (1) are as follows: 1 to 3 parts of γ-glycidyloxypropyltrimethoxysilane are added to 20 to 50 parts of anhydrous ethanol and stirred evenly, acetic acid is added to adjust the pH of the solution to 4 to 5, and stirred at 20 to 30° C. and 80 rpm for 1 to 2 hours to obtain the γ-glycidyloxypropyltrimethoxysilane hydrolyzate.

[0013] Furthermore, the oil phase mixture in step (3) is prepared by mixing polyglycerol polyricinoleate, oil, and emulsifier in a mass ratio of (2-16): (1-17): (1-9).

[0014] Furthermore, the oil is selected from any one or more of squalane, ethylhexyl palmitate, jojoba seed oil, isoamyl laurate, ethylhexyl cocoate, olive oil, and soybean oil.

[0015] Furthermore, the emulsifier is selected from any one or more of arachidyl glucoside, polyglyceryl-10 diisostearate, polyglyceryl-10 oleate, and polyglyceryl-10 myristate.

[0016] Furthermore, the external water phase in step (4) is prepared by mixing deionized water, an acid-base regulator, and a preservative in a mass ratio of (20-30): (0.1-5.7): (0.005-1).

[0017] Furthermore, the acid-base regulator is selected from any one or more of citric acid, lactic acid, tromethamine, triethanolamine, and disodium hydrogen phosphate.

[0018] Furthermore, the preservative is selected from any one or more of butylene glycol, phenoxyethanol, 1,2-hexanediol, p-hydroxyacetophenone, and 1,2-pentanediol.

[0019] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0020] The present invention adopts a two-step emulsification method to first prepare a whitening agent and polyglycerol polyricinoleate into colostrum. After the whitening agent is adsorbed on the oil-water interface, polyglycerol polyricinoleate further fills the gaps between kaolin lamellae to form a tighter interface film, which significantly improves the stability of the emulsion and prevents droplet aggregation and stratification. At the same time, the oil control and cleaning functions of kaolin are combined with the moisturizing and nourishing properties of polyglycerol polyricinoleate, so that the emulsion has the dual effects of cleaning and skin care. Then, a multiple emulsion system is formed with the external water phase, and the secondary emulsification allows the outer layer emulsifier to better wrap the primary emulsion droplets, thereby enhancing the overall stability of the emulsion and indirectly improving the overall performance.

[0021] Among them, the whitening agent uses kaolin as raw material. First, the silicon-oxygen bond in γ-glycidyloxypropyltrimethoxysilane is used to firmly combine with the surface of kaolin for modification, thereby improving the dispersibility, adsorption capacity and compatibility of kaolin; then the epoxy group in the silane coupling agent is opened and combined with the amino group of aspartic acid under the action of a bridging agent to form a stable three-dimensional network structure, which can form a structure similar to a "protective film" on the skin surface to block the direct invasion of external dust, pollutants, ultraviolet rays and other harmful substances on the skin, and reduce their damage to skin cells. At the same time, it helps to maintain the moisture and nutrients inside the skin, prevent their loss, stabilize the internal environment of the skin, enhance the skin's own barrier function, and achieve moisturizing and antioxidant effects. On this basis, aspartic acid has acid-base buffering capacity, can regulate the pH of the skin surface, inhibit the growth of harmful microorganisms, achieve antibacterial effects, and can participate in skin metabolism, promote cell self-repair and the synthesis of natural moisturizing factors, thereby further enhancing the moisturizing function. DETAILED DESCRIPTION

[0022] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0023] In order to more clearly illustrate the method provided by the present invention, the following examples are used to describe in detail the test methods of various indicators of the whitening cosmetics prepared in the following examples are as follows:

[0024] Stability: Take the same mass of the embodiment and the comparative example, store them at room temperature for 9 weeks, and take out samples every 3 weeks to observe whether there is demulsification, stratification, discoloration, precipitation, etc.

[0025] Melanin change rate: Take the same mass of the embodiment and the comparative example, apply them to different areas on the inner side of the forearm every morning and evening, measure the reflectance of the skin of the test area after irradiation with light of a specific wavelength before the experiment (Day 1) and after 28 days of use (Day 28) to determine the melanin content in the skin, and record the melanin change rate.

[0026] Moisturizing property: Take the same mass of the Example and the Comparative Example, and evaluate the moist feeling after applying it on the skin of 5 professional judges according to the following evaluation criteria. (4 points: very moist, 3 points: quite moist, 2 points: moist, 1 point: almost no moist, 0 points: no moist)

[0027] Example 1

[0028] (1) adding 1 part of γ-glycidyloxypropyltrimethoxysilane to 20 parts of anhydrous ethanol and stirring evenly, adding acetic acid to adjust the pH of the solution to 4, stirring at 20° C. and 80 rpm for 1 hour to obtain a γ-glycidyloxypropyltrimethoxysilane hydrolyzate;

[0029] (2) 5 parts of kaolin were uniformly dispersed in 60 parts of anhydrous ethanol, the temperature was raised to 55°C, 3 parts of γ-glycidyloxypropyltrimethoxysilane hydrolyzate were added dropwise at a rate of 2 mL / min, the mixture was stirred at 100 rpm for 4 h, naturally cooled to room temperature, transferred to a centrifuge and centrifuged at 3000 rpm for 5 min, the solid was collected, washed twice with ethanol and deionized water alternately, and dried at 50°C for 10 h to obtain modified kaolin;

[0030] (3) Under a nitrogen atmosphere, 6 parts of modified kaolin were dispersed in 80 parts of deionized water, 3 parts of aspartic acid were added, and the mixture was stirred at 100 rpm for 24 hours, then the temperature was raised to 60° C. and the reaction was continued for 32 hours. After the reaction was completed, the solid was filtered and collected, washed with deionized water for 3 times, and dried in an oven at 25° C. for 16 hours to obtain a whitening agent;

[0031] (4) 5 parts of a whitening agent are uniformly dispersed in 20 parts of deionized water, and 30 parts of an oil phase mixture prepared by mixing polyglycerol polyricinoleate, jojoba seed oil, and arachidyl glucoside in a mass ratio of 2:1:1 is added, and the mixture is rapidly stirred and emulsified at 30° C. and 1000 rpm for 20 minutes, and then naturally cooled to room temperature to obtain colostrum;

[0032] (5) 30 parts of an external aqueous phase mixture prepared by mixing deionized water, citric acid and butylene glycol in a mass ratio of 20:0.1:0.005 was added to the colostrum prepared in step (4) under stirring at 1000 rpm and mixed for 10 minutes to prepare a whitening cosmetic.

[0033] Example 2

[0034] (1) adding 2 parts of γ-glycidyloxypropyltrimethoxysilane to 35 parts of anhydrous ethanol and stirring evenly, adding acetic acid to adjust the pH of the solution to 4.5, stirring at 25° C. and 80 rpm for 1.5 hours to obtain a γ-glycidyloxypropyltrimethoxysilane hydrolyzate;

[0035] (2) 10 parts of kaolin were uniformly dispersed in 105 parts of anhydrous ethanol, the temperature was raised to 60°C, 7 parts of γ-glycidyloxypropyltrimethoxysilane hydrolyzate were added dropwise at a rate of 2 mL / min, the mixture was stirred at 100 rpm for 5 h, naturally cooled to room temperature, transferred to a centrifuge and centrifuged at 3000 rpm for 10 min, the solid was collected, washed twice with ethanol and deionized water alternately, and dried at 55°C for 13 h to obtain modified kaolin;

[0036] (3) Under a nitrogen atmosphere, 8 parts of modified kaolin were dispersed in 100 parts of deionized water, 4 parts of aspartic acid were added, and the mixture was stirred at 100 rpm for 30 h, then heated to 65° C. and continued to react for 46 h. After the reaction was completed, the solid was filtered and collected, washed three times with deionized water, and dried in an oven at 30° C. for 20 h to obtain a whitening agent;

[0037] (4) 10 parts of a whitening agent are uniformly dispersed in 30 parts of deionized water, and 40 parts of an oil phase mixture prepared by mixing polyglycerol polyricinoleate, isopentyl laurate, and polyglycerol-10 diisostearate in a mass ratio of 1:1:2.5 is added, and the mixture is rapidly stirred and emulsified at 35°C and 1000 rpm for 25 minutes, and then naturally cooled to room temperature to obtain colostrum;

[0038] (5) 40 parts of an external aqueous phase mixture prepared by mixing deionized water, lactic acid, and phenoxyethanol in a mass ratio of 25:2.9:0.5 was added to the colostrum prepared in step (4) under stirring at 1000 rpm and mixed for 15 minutes to prepare a whitening cosmetic.

[0039] Example 3

[0040] (1) adding 3 parts of γ-glycidyloxypropyltrimethoxysilane to 50 parts of anhydrous ethanol and stirring evenly, adding acetic acid to adjust the pH of the solution to 5, stirring at 30° C. and 80 rpm for 2 hours to obtain a γ-glycidyloxypropyltrimethoxysilane hydrolyzate;

[0041] (2) 15 parts of kaolin were uniformly dispersed in 150 parts of anhydrous ethanol, the temperature was raised to 65°C, 11 parts of γ-glycidyloxypropyltrimethoxysilane hydrolyzate were added dropwise at a rate of 2 mL / min, the mixture was stirred at 100 rpm for 6 h, naturally cooled to room temperature, transferred to a centrifuge and centrifuged at 3000 rpm for 15 min, the solid was collected, washed twice with ethanol and deionized water alternately, and dried at 60°C for 16 h to obtain modified kaolin;

[0042] (3) Under a nitrogen atmosphere, 10 parts of modified kaolin were dispersed in 120 parts of deionized water, 5 parts of aspartic acid were added, and the mixture was stirred at 100 rpm for 36 hours, then the temperature was raised to 70°C and the reaction was continued for 60 hours. After the reaction was completed, the solid was filtered and collected, washed with deionized water for 3 times, and dried in an oven at 35°C for 24 hours to obtain a whitening agent;

[0043] (4) 15 parts of a whitening agent are uniformly dispersed in 40 parts of deionized water, and 50 parts of an oil phase mixture prepared by mixing polyglycerol polyricinoleate, ethylhexyl cocoate, and polyglycerol-10 oleate in a mass ratio of 16:17:9 is added, and the mixture is rapidly stirred and emulsified at 40° C. and 1000 rpm for 30 minutes, and then naturally cooled to room temperature to obtain colostrum;

[0044] (5) 50 parts of an external aqueous phase mixture prepared by mixing deionized water, triethanolamine, and 1,2-hexanediol in a mass ratio of 30:5.7:1 was added to the colostrum prepared in step (4) under stirring at 1000 rpm and mixed for 20 minutes to prepare a whitening cosmetic.

[0045] Comparative Example 1

[0046] The difference between Comparative Example 1 and Example 2 is that there is no step (4), and step (5) is changed to: 10 parts of whitening agent are uniformly dispersed in 30 parts of deionized water, 40 parts of external water phase prepared by mixing deionized water, lactic acid, and phenoxyethanol in a mass ratio of 25:2.9:0.5 are added, and 40 parts of oil phase mixture prepared by mixing polyglycerol polyricinoleate, isopentyl laurate, and polyglycerol-10 diisostearate in a mass ratio of 1:1:2.5 are added, and the mixture is rapidly stirred and emulsified at 35°C and 1000 rpm for 25 minutes, and naturally cooled to room temperature to prepare whitening cosmetics. The remaining steps are the same as those in Example 2.

[0047] Comparative Example 2

[0048] The difference between Comparative Example 2 and Example 2 is that there are no steps (1) and (2), and step (3) is changed to: in a nitrogen atmosphere, 8 parts of kaolin are dispersed in 100 parts of deionized water, 4 parts of aspartic acid are added, and the mixture is stirred at 100 rpm for 30 hours, then the temperature is raised to 65° C. and the reaction is continued for 46 hours. After the reaction is completed, the solid is filtered and collected, washed with deionized water 3 times, and dried in an oven at 30° C. for 20 hours to obtain a whitening agent. The remaining steps are the same as those in Example 2.

[0049] Comparative Example 3

[0050] The difference between Comparative Example 3 and Example 2 is that there is no step (3), and step (4) is changed to: 10 parts of modified kaolin are uniformly dispersed in 30 parts of deionized water, 40 parts of an oil phase mixture prepared by mixing polyglycerol polyricinoleate, isopentyl laurate, and polyglycerol-10 diisostearate in a mass ratio of 1:1:2.5 are added, and the mixture is rapidly stirred and emulsified at 35°C and 1000 rpm for 25 minutes, and naturally cooled to room temperature to obtain colostrum. The remaining steps are the same as those in Example 2.

[0051] Comparative Example 4

[0052] (1) adding 2 parts of γ-glycidyloxypropyltrimethoxysilane to 35 parts of anhydrous ethanol and stirring evenly, adding acetic acid to adjust the pH of the solution to 4.5, stirring at 25° C. and 80 rpm for 1.5 hours to obtain a γ-glycidyloxypropyltrimethoxysilane hydrolyzate;

[0053] (2) Under a nitrogen atmosphere, 7 parts of γ-glycidyloxypropyltrimethoxysilane hydrolyzate were added to 4 parts of aspartic acid, and the mixture was stirred at 100 rpm for 30 hours, then the temperature was raised to 65° C. and the reaction was continued for 46 hours. After the reaction was completed, 40 parts of anhydrous ethanol were added, and the mixture was stirred for 10 minutes. The liquid was filtered and concentrated at a vacuum degree of -0.1 MPa and 40° C. for 2 hours to obtain a whitening agent;

[0054] (3) 10 parts of a whitening agent are uniformly dispersed in 30 parts of deionized water, and 40 parts of an oil phase mixture prepared by mixing polyglycerol polyricinoleate, isopentyl laurate, and polyglycerol-10 diisostearate in a mass ratio of 1:1:2.5 is added, and the mixture is rapidly stirred and emulsified at 35°C and 1000 rpm for 25 minutes, and then naturally cooled to room temperature to obtain colostrum;

[0055] (4) 40 parts of an external aqueous phase mixture prepared by mixing deionized water, lactic acid and phenoxyethanol in a mass ratio of 25:2.9:0.5 was added to the colostrum prepared in step (4) under stirring at 1000 rpm and mixed for 15 minutes to prepare a whitening cosmetic.

[0056] Effect example

[0057] The following Table 1 shows the performance analysis results of the whitening cosmetics using Examples 1 to 3 of the present invention and Comparative Examples 1 to 4.

[0058] Table 1

[0059] stability Melanin change rate Moisturizing Example 1 No change -19.7％ 4 Example 2 No change -21.3％ 4 Example 3 No change -20.4％ 4 Comparative Example 1 Demulsification and stratification -18.6％ 3 Comparative Example 2 Solid precipitation -18.8％ 2 Comparative Example 3 Small amount of fluid leakage -16.7％ 1 Comparative Example 4 Demulsification and stratification -14.5％ 3

[0060] From the comparison of the experimental data of Examples 1, 2, and 3 with those of Comparative Example 1, it can be found that, through the two-step emulsification method, the whitening agent and polyglycerol polyricinoleate are first prepared into colostrum, and after the whitening agent is adsorbed on the oil-water interface, polyglycerol polyricinoleate further fills the gaps between the kaolin sheets to form a tighter interface film, which significantly improves the stability of the emulsion and prevents the droplets from coalescing and stratifying. At the same time, the oil control and cleaning functions of kaolin are combined with the moisturizing and nourishing properties of polyglycerol polyricinoleate, so that the emulsion has the dual effects of cleaning and skin care; and then forms a multiple emulsion system with the external water phase, and the secondary emulsification allows the outer layer emulsifier to better wrap the primary emulsion droplets, enhance the overall stability of the emulsion, and indirectly improve the overall performance; from the comparison of the experimental data of Examples 1, 2, and 3 with Comparative Examples 2, 3, and 4, it can be found that, using kaolin as a raw material, first using the silicon in γ-glycidyloxypropyltrimethoxysilane The oxygen bonds are firmly combined with the surface of kaolin to modify it, thereby improving the dispersibility, adsorption capacity and compatibility of kaolin; then the epoxy group in the silane coupling agent is opened and combined with the amino group of aspartic acid under the action of the bridging agent to form a stable three-dimensional network structure, which can form a structure similar to a "protective film" on the skin surface, blocking the direct invasion of external dust, pollutants, ultraviolet rays and other harmful substances on the skin, reducing their damage to skin cells, and at the same time, helping to maintain moisture and nutrients inside the skin, prevent their loss, stabilize the internal environment of the skin, enhance the skin's own barrier function, and achieve moisturizing and anti-oxidation effects. On this basis, aspartic acid has acid-base buffering capacity, can regulate the pH of the skin surface, inhibit the growth of harmful microorganisms, achieve antibacterial effects, and can participate in skin metabolism, promote cell self-repair and the synthesis of natural moisturizing factors, and further enhance the moisturizing function.

[0061] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and scope of the equivalent elements of the claims be included in the invention. Any marking in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A method for preparing a whitening cosmetic, characterized in that: The method comprises the following preparation steps: (1) 5 to 15 parts of kaolin are uniformly dispersed in 60 to 150 parts of anhydrous ethanol, the temperature is raised to 55 to 65° C., 3 to 11 parts of γ-glycidyloxypropyltrimethoxysilane hydrolyzate are added dropwise, the mixture is stirred at 100 rpm for 4 to 6 hours, the mixture is naturally cooled to room temperature, the mixture is transferred to a centrifuge and centrifuged at 3000 rpm for 5 to 15 minutes, the solid is collected, the solid is washed twice with ethanol and deionized water alternately, and the solid is dried at 50 to 60° C. for 10 to 16 hours to obtain modified kaolin; (2) Under a nitrogen atmosphere, 6 to 10 parts of modified kaolin are dispersed in 80 to 120 parts of deionized water, 3 to 5 parts of aspartic acid are added, and the mixture is stirred at 100 rpm for 24 to 36 hours, then the temperature is raised to 60 to 70° C., and the reaction is continued for 32 to 60 hours. After the reaction is completed, the solid is filtered and collected, washed with deionized water for 3 times, and dried in an oven at 25 to 35° C. for 16 to 24 hours to obtain a whitening agent; (3) evenly dispersing 5 to 15 parts of a whitening agent in 20 to 40 parts of deionized water, adding 30 to 50 parts of the oil phase mixture, rapidly stirring and emulsifying at 30 to 40° C. and 1000 rpm for 20 to 30 minutes, and naturally cooling to room temperature to obtain colostrum; (4) Add 30 to 50 parts of the external aqueous phase mixture to the colostrum prepared in step (3) under stirring at 1000 rpm, and mix for 10 to 20 minutes to prepare a whitening cosmetic.

2. The method for preparing a whitening cosmetic according to claim 1, characterized in that: The rate of dropping in step (1) is 2 mL / min.

3. The method for preparing a whitening cosmetic according to claim 1, characterized in that: The preparation steps of the γ-glycidyloxypropyltrimethoxysilane hydrolyzate in step (1) are as follows: 1 to 3 parts of γ-glycidyloxypropyltrimethoxysilane are added to 20 to 50 parts of anhydrous ethanol and stirred evenly, acetic acid is added to adjust the pH of the solution to 4 to 5, and the solution is stirred at 20 to 30° C. and 80 rpm for 1 to 2 hours to obtain the γ-glycidyloxypropyltrimethoxysilane hydrolyzate.

4. The method for preparing a whitening cosmetic according to claim 1, characterized in that: The oil phase mixture in step (3) is prepared by mixing polyglycerol polyricinoleate, oil, and emulsifier in a mass ratio of (2-16): (1-17): (1-9).

5. The method for preparing a whitening cosmetic according to claim 1, characterized in that: The oil is selected from any one or more of squalane, ethylhexyl palmitate, jojoba seed oil, isoamyl laurate, ethylhexyl cocoate, olive oil, and soybean oil.

6. The method for preparing a whitening cosmetic according to claim 1, characterized in that: The emulsifier is selected from any one or more of arachidyl glucoside, polyglyceryl-10 diisostearate, polyglyceryl-10 oleate, and polyglyceryl-10 myristate.

7. The method for preparing a whitening cosmetic according to claim 1, characterized in that: The external water phase in step (4) is prepared by mixing deionized water, an acid-base regulator, and a preservative in a mass ratio of (20-30): (0.1-5.7): (0.005-1).

8. The method for preparing a whitening cosmetic according to claim 1, characterized in that: The acid-base regulator is selected from any one or more of citric acid, lactic acid, tromethamine, triethanolamine, and disodium hydrogen phosphate.

9. The method for preparing a whitening cosmetic according to claim 1, characterized in that: The preservative is selected from any one or more of butylene glycol, phenoxyethanol, 1,2-hexanediol, p-hydroxyacetophenone, and 1,2-pentanediol.