Cosmetic rheological agent and its use in high pseudoplasticity coefficient cosmetics

Abstract

The present application provides a kind of cosmetic rheological agent, the rheological agent is the colloidal suspension of glutamic acid / polyvinyl alcohol-zinc aluminum hydrotalcite-like supramolecular complex, is obtained by glutamic acid-methoxy zinc aluminum hydrotalcite hydrolysis reaction.The suspension is very stable, itself is not prone to solid-liquid stratification phenomenon;At the same time, the rheological agent is added to the cosmetic containing liquid natural rubber also does not produce solid-liquid stratification phenomenon, and can significantly improve the pseudoplasticity coefficient of the cosmetic containing liquid natural rubber, prompting the cosmetic containing liquid natural rubber has better shear thinning performance when using, this kind of high shear coefficient of the cosmetic containing liquid natural rubber can better spread on the skin surface, and has good skin moisturizing effect.

Description

Technical fields:

[0001] This invention provides a cosmetic rheology modifier, its preparation method, and its application in cosmetics with high pseudoplasticity coefficients, belonging to the field of daily cosmetics. Background technology:

[0002] Emulsion cosmetics are commonly used skin care products that can effectively prevent and treat rough, dry, and cracked skin on the face, hands, and feet, and heal and smooth skin cracks. Viscosity is one of the important physical properties and performance indicators for emulsion cosmetics, and it also affects the appearance of the product and the consumer's practical experience (Reference 1: Study on the rheological properties of hand cream, Journal of Zhengzhou University of Light Industry (Natural Science Edition), 2014, 29(1), 83-85). Generally speaking, emulsion cosmetics with a high pseudoplasticity coefficient value indicate that the cosmetic has better shear-thinning properties, that is, the cosmetic has better spreading and coating properties when used on the skin, that is, it can better cover the skin surface and achieve better moisturizing effect (Reference 2: Basic properties of rheological modifiers for cosmetics, Fragrance and Cosmetics, 2021, 12(6), 48-51). Reference 3 (ZL2021107279881) reports a skin moisturizer prepared by stirring liquid natural rubber with a gelatin-lignin-urea-montmorillonite organic-inorganic colloidal complex. The moisturizer containing liquid rubber was then combined with cetearyl alcohol ether-10, dimethyl silicone oil, water and other additives according to a cosmetic formulation to prepare a cosmetic emulsion containing liquid natural rubber. The cosmetic emulsion has good stability and moisturizing properties. It should be noted that the liquid natural rubber used in Reference 3 is an oligomer with a molecular weight as low as 20,000, which is formed by oxidizing and degrading natural rubber. The ends of the liquid natural rubber molecular chains also have carboxyl groups due to oxidation. Although liquid natural rubber has a certain fluidity, its molecular chain structure is relatively extended and the distance between the ends of the molecular chains is relatively large. This results in a high apparent viscosity of liquid natural rubber, which in turn leads to poor shear thinning properties of the emulsion cosmetic containing liquid natural rubber provided in Reference 3. That is, the pseudoplasticity coefficient of this emulsion cosmetic containing liquid natural rubber is not high, which also reduces the spreadability and practical application effect of the cosmetic containing liquid natural rubber on the skin. Summary of the Invention:

[0003] To address the problems existing in the prior art, this invention provides a cosmetic rheology modifier, its preparation method, and its application in the preparation of cosmetics with high pseudoplasticity coefficients.

[0004] The technical solution of the present invention:

[0005] A cosmetic rheology modifier, the preparation steps of which are as follows:

[0006] (1) Dissolve NaOH in methanol solvent at 45-55℃ to obtain solution A, wherein the weight ratio of NaOH to methanol is 1:(5.8-7.4);

[0007] (2) Zinc nitrate hexahydrate and aluminum nitrate nonahydrate are dissolved in methanol at room temperature to obtain solution B, wherein the weight ratio of zinc nitrate hexahydrate, aluminum nitrate nonahydrate and methanol is (1.73-2.75):1:(42-48.6);

[0008] (3) Add the solution A obtained in step (1) dropwise to the solution B obtained in step (2) at 45-55℃ and stirring at 1500-3000r / min. The dropwise rate is 1 drop every 1-3 seconds. When the pH of the resulting mixture is 7.5-8.5, the dropwise addition ends. Continue the reaction for 10-24 hours, and then obtain a white mixture C.

[0009] (4) Heat the white mixture C obtained in step (3) to 55-65℃, add sodium glutamate, and then stir at a speed of 1000-3000 r / min for 3-12 h to obtain white mixture D, wherein the weight ratio of white mixture C obtained in step (3) to sodium glutamate is (7-14):(0.1-0.21);

[0010] (5) Filter the mixture D obtained in step (4) at room temperature. Wash the filtered gel with methanol solvent 3-5 times to obtain white gel E, wherein the weight ratio of mixture D to methanol solvent is 1:3.

[0011] (6) Dissolve monosodium glutamate and polyvinyl alcohol in water, with a weight ratio of monosodium glutamate, polyvinyl alcohol and water of (0.3-0.5):1:(80-120). React at room temperature with stirring for 1-3 hours at a stirring speed of 300-800 r / min. Then add sodium hydroxide to adjust the pH of the solution to 8.0-10.0 and continue the reaction for 1-3 hours to obtain solution F.

[0012] (7) Add the gel E obtained in step (5) to solution F at 18-35℃ and under stirring conditions. The stirring speed is 500-1000r / min. After stirring for 2-12h, a colloidal suspension containing glutamic acid / polyvinyl alcohol-zinc aluminum hydrotalcite is obtained, which is a cosmetic rheology modifier. The weight ratio of solution F to gel E is (1-3):1.

[0013] Another object of the present invention is to prepare a cosmetic with a high pseudoplasticity coefficient using the above-mentioned cosmetic rheology modifier, characterized in that the raw materials used in the preparation method include: the cosmetic rheology modifier prepared by steps (1)-(7) above and the skin moisturizer based on liquid natural rubber provided in reference 3, and the preparation steps are as follows:

[0014] In an oil phase reactor, the oily additives are stirred at 85°C and 50 r / min until they melt and are mixed evenly. In an emulsification reactor, the emulsifier, chelating agent, cosmetic rheology modifier prepared in steps (1)-(7), skin moisturizer based on liquid natural rubber, and deionized water are stirred evenly at 85°C and 50 r / min. The weight ratio of cosmetic rheology modifier to skin moisturizer based on liquid natural rubber is (15-25):100. The material in the oil phase reactor is transferred to the emulsification reactor. After the two phases are mixed, the homogenizer is started and homogenized at 5000 r / min. The mixture is stirred continuously. When the temperature drops to 40°C, the fragrance is added to obtain a cosmetic with a high pseudoplasticity coefficient.

[0015] The oily additives include 2.5 wt% cetearyl alcohol ether-10, 5.0 wt% cetyl / octadecyl alcohol, 3.0 wt% dimethyl silicone oil, 3.0 wt% alkyl benzoate, and 4.0 wt% isopropyl myristate.

[0016] The emulsifier comprises 0.15 wt% Carbomer 941, 0.15 wt% xanthan gum, 2.0 wt% hard fatty acid glyceride (and) lauryl polyoxyethylene (23) ether.

[0017] The chelating agent is 0.08 wt% EDTA-2Na; the flavoring agent includes 0.25 wt% fragrance and 0.1 wt% Crème de la Mer.

[0018] The amount of the skin moisturizer based on liquid natural rubber added is 10-20% of the total mass of the cosmetic. After deducting the percentage content of each component in the system, the remainder is the percentage content of water. All water used in the above preparation methods is deionized water.

[0019] The present invention differs from the prior art in that it achieves the following technical effects:

[0020] The experimental results of the efficacy examples demonstrate that the cosmetic rheology modifier prepared in this invention is a colloidal suspension. This suspension is highly stable and does not readily undergo solid-liquid stratification. Furthermore, when added to cosmetics containing liquid natural rubber, this rheology modifier does not induce solid-liquid stratification and significantly increases the pseudoplasticity coefficient of the cosmetics containing liquid natural rubber. This results in better shear-thinning properties during use, allowing the cosmetics with a high shear coefficient to spread more effectively on the skin surface and achieve a superior skin moisturizing effect. The above technical effects are due to the following working principle:

[0021] In steps (1)-(3) of the preparation of the cosmetic rheology modifier of the present invention, zinc nitrate hexahydrate and aluminum nitrate nonahydrate react in methanol solvent and in the presence of sodium hydroxide to obtain a mixture C containing methoxy zinc aluminum hydrotalcite compounds. The classic hydrotalcite is magnesium aluminum carbonate type hydrotalcite, and the structure of magnesium aluminum carbonate type hydrotalcite is very similar to the layered structure of brucite [Mg(OH)2]. The hydrotalcite layers are formed by MgO6 octahedra sharing common edges to form unit layers, and the Mg on the layer is located in the unit layer. 2+ Can be used by Al within a certain range 3+ Isomorphic substitution results in positively charged layers, and CO3 between the layers... 2- The positive charge balance on the layers makes the overall structure of magnesium aluminum carbonate type hydrotalcite electrically neutral. If the magnesium in magnesium aluminum type hydrotalcite is replaced by zinc, it becomes zinc aluminum type hydrotalcite. Zinc is used in cosmetics for its antibacterial, sebum-inhibiting, and anti-inflammatory effects. In steps (1)-(3), methanol solvent is used instead of water solvent in the reaction system. Methanol solvent can react with the metal hydroxyl groups (M-OH) on the zinc aluminum type hydrotalcite layers under the action of sodium hydroxide to form M-OCH3 groups. The space between the layers is NO3. - Anions are used to balance the positive charge on the hydrotalcite layers.

[0022] In steps (4) and (5) of the preparation of cosmetic rheology modifiers, the methoxy zinc aluminum hydrotalcite prepared in steps (1)-(3) undergoes an interlayer ion exchange reaction with sodium glutamate, that is, the negatively charged glutamate anion replaces the NO3 between the layers of the methoxy zinc aluminum hydrotalcite. - Anions were used to obtain a mixed solution D containing a glutamate-methoxyzinc-aluminum layered double hydroxide (TLD) intercalation complex. After washing and filtration with methanol, a colloidal substance E of the glutamate-methoxyzinc-aluminum LTD was obtained. The glutamate anions located between the layers increase the distance between the inorganic layers and enlarge the intercalation space. This facilitates intercalation ion exchange reactions between other negatively charged complexes and the glutamate anions between the layers, leading to the formation of new intercalation-type LTD compounds.

[0023] In step (6) of the preparation of cosmetic rheology modifiers, sodium glutamate dissolves in water and ionizes into negatively charged glutamate anions. The glutamate anions with carboxyl and amino groups and the polyvinyl alcohol molecules with hydroxyl groups can form hydrogen bonds in aqueous solution to generate a negatively charged glutamate / polyvinyl alcohol supramolecular complex. The free sodium ions in the solution F containing the glutamate / polyvinyl alcohol supramolecular complex balance or neutralize the negative charge of the entire system.

[0024] In step (7) of the preparation of the cosmetic rheology modifier of the present invention, while the glutamic acid-zinc-aluminum hydrotalcite gel E is in contact with the aqueous solvent and undergoes a hydrolysis reaction, it also undergoes an interlayer ion exchange reaction with the negatively charged glutamic acid / polyvinyl alcohol supramolecular complex. The M-OCH3 group in the glutamic acid-zinc-aluminum hydrotalcite gel E is readily hydrolyzed in water to generate M-OH. This hydrolysis reaction is relatively rapid and vigorous, and the energy released by the reaction can instantly turn the gel E into very small colloidal particles. The generated tiny colloidal particles can be stably suspended in the aqueous solution to form a colloidal suspension. In the E-hydrolysis reaction of glutamic acid-methoxyzinc-aluminum hydrotalcite gel, when methanol molecules formed by the hydrolysis of M-OCH3 groups detach from the inorganic layers, the interaction between the inorganic layers of the zinc-aluminum hydrotalcite weakens. This facilitates interlayer ion exchange between the negatively charged glutamic acid / polyvinyl alcohol supramolecular complex and the glutamate ions between the inorganic layers of the zinc-aluminum hydrotalcite, generating a glutamic acid / polyvinyl alcohol-zinc-aluminum hydrotalcite interlayered complex. The exchanged glutamate ions become free ions in the solution. These free glutamic acid ions can act as crosslinking agents between polyvinyl alcohol molecular chains in subsequent reactions, helping to crosslink the polyvinyl alcohol chains into a network structure and confining the liquid natural rubber molecules within the network structure. This reduces the end-chain distance of the structurally restricted liquid natural rubber molecules, lowers its viscosity, and thus improves the shear-thinning properties of cosmetics containing liquid natural rubber. In the glutamic acid / polyvinyl alcohol-zinc aluminum hydrotalcite layered intercalation organic-inorganic composite obtained in step (7), due to the relatively long polyvinyl alcohol chain, it is not entirely embedded between the zinc aluminum hydrotalcite inorganic layers. Instead, some polyvinyl alcohol molecular chains are embedded between the hydrotalcite layers, while others are suspended outside the hydrotalcite layers. The hydroxyl groups on the polyvinyl alcohol chains suspended outside the hydrotalcite inorganic layers can interact with the carboxyl groups at the ends of the liquid natural rubber molecular chains. This is like the "arms" extended by the glutamic acid / polyvinyl alcohol-zinc aluminum hydrotalcite layered intercalation composite clamping the liquid natural rubber molecules head to tail, restricting the extension range of the liquid natural rubber molecular chains, reducing the end-to-end distance, and decreasing the contribution of the liquid natural rubber molecules to the viscosity of the system. This achieves the effect of reducing the viscosity of cosmetic emulsions containing liquid natural rubber molecules.

[0025] In the preparation steps of cosmetics with high pseudoplasticity coefficient, the rheology modifier prepared in steps (1)-(7) and the moisturizer containing liquid natural rubber are mixed and co-heated in an emulsion system. During the mixing process, the glutamic acid / polyvinyl alcohol-zinc aluminum hydrotalcite layered composite in the rheology modifier captures liquid natural rubber molecules through polyethanol chains suspended outside the inorganic layer, and confines the liquid natural rubber molecules in the network composed of polyvinyl alcohol chains and hydrotalcite layers. During the heating process, the two carboxylic acid groups of the free glutamic acid molecules in the rheology modifier undergo esterification reaction with the hydroxyl groups on the polyethanol chains under the alkaline catalysis of the hydrotalcite layers, crosslinking the polyethanol chains. The distance between the chains in the crosslinked polyethanol network is shortened, and the density of the three-dimensional network formed by the polyvinyl alcohol chains and the inorganic layer increases, thereby compressing the extension space of the liquid natural rubber molecular chains interacting with the polyvinyl alcohol chains. The end-to-end distance of the compressed liquid natural rubber molecules is also further reduced, which correspondingly further reduces the viscosity of the cosmetic emulsion containing liquid natural rubber molecules. Because the polyvinyl alcohol molecular chains are anchored on the rigid hydrotalcite inorganic layer, the contraction force generated by the polyvinyl alcohol chains during the crosslinking process is supported by the rigid hydrotalcite inorganic layer. This effectively compresses the extension space of the liquid rubber molecules, reduces the end-to-end distance of the liquid natural rubber molecules, reduces the viscosity of cosmetic emulsions containing liquid natural rubber molecules, improves the shear thinning properties of cosmetics, and increases their pseudoplasticity coefficient. Attached Figure Description

[0026] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof.

[0027] Figure 1 In the diagram, a represents the zinc-aluminum hydrotalcite prepared in Comparative Example 6 of this invention, b represents the methoxy zinc-aluminum hydrotalcite prepared in Example 3, c represents the glutamic acid-methoxy zinc-aluminum hydrotalcite, and d represents the X-ray powder diffraction pattern of the glutamic acid / polyvinyl alcohol-zinc-aluminum hydrotalcite.

[0028] Figure 2 This is a process flow diagram of a cosmetic rheology modifier prepared according to the present invention.

[0029] Figure 3 This is a process flow diagram of the cosmetic with a high pseudoplasticity coefficient prepared according to the present invention.

[0030] Figure 4 These are rheological curves of cosmetics with high pseudoplasticity coefficients prepared according to the present invention. a is the rheological curve of the cosmetic prepared with the rheology modifier obtained in Example 3 in Application Example 11, and b is the rheological curve of the cosmetic prepared without the rheology modifier in Application Example 11. Detailed Implementation

[0031] The above-mentioned and other technical features and advantages of the present invention will be described in more detail below with reference to the embodiments. Unless otherwise specified, all chemical raw materials used in the following embodiments are commercially available, chemically pure reagents; sodium glutamate, purity 99%, purchased from Shandong Siyang Biotechnology Co., Ltd.; polyvinyl alcohol, model PVA2488, viscosity 20-26 mPa·s, purchased from Shanghai Yingjia Industrial Development Co., Ltd.; the liquid natural rubber-based skin moisturizer was prepared according to the steps described in Example 4 of Reference 3.

[0032] Example 1

[0033] A cosmetic rheology modifier, the preparation steps of which are as follows:

[0034] (1) Dissolve NaOH in methanol solvent at 45℃ to obtain solution A, wherein the weight ratio of NaOH to methanol is 1:5.8;

[0035] (2) Zinc nitrate hexahydrate and aluminum nitrate nonahydrate are dissolved in methanol at room temperature to obtain solution B, wherein the weight ratio of zinc nitrate hexahydrate, aluminum nitrate nonahydrate and methanol is 1.73:1:42.

[0036] (3) The solution A obtained in step (1) is added dropwise to the solution B obtained in step (2) at 45°C and stirring at 1500 r / min. The dropwise rate is 1 drop per second. When the pH of the resulting mixture is 7.5, the dropwise addition is stopped. The reaction continues for 10 h, and then a white mixture C is obtained.

[0037] (4) Heat the white mixture C obtained in step (3) to 55°C, add sodium glutamate, and then stir at a speed of 1000 r / min for 3 h to obtain white mixture D. The weight ratio of white mixture C obtained in step (3) to sodium glutamate is 7:0.1.

[0038] (5) Filter the mixture D obtained in step (4) at room temperature. Wash the filtered gel with methanol solvent three times to obtain white gel E. The weight ratio of mixture D to methanol solvent is 1:3.

[0039] (6) Dissolve monosodium glutamate and polyvinyl alcohol in water with a weight ratio of 0.3:1:80. React at room temperature with stirring for 1 hour at a stirring speed of 300 r / min. Then add sodium hydroxide to adjust the pH of the solution to 8.0 and continue to react for 1 hour to obtain solution F.

[0040] (7) The gel E obtained in step (5) is added to solution F at 18°C ​​and under stirring conditions. The stirring speed is 500 r / min. After stirring for 2 hours, a colloidal suspension containing glutamic acid / polyvinyl alcohol-zinc aluminum hydrotalcite is obtained, which is a cosmetic rheology modifier. The weight ratio of solution F to gel E is 1:1.

[0041] Example 2

[0042] A cosmetic rheology modifier, the preparation steps of which are as follows:

[0043] (1) Dissolve NaOH in methanol at 47℃ to obtain solution A, wherein the weight ratio of NaOH to methanol is 1:6.2;

[0044] (2) Zinc nitrate hexahydrate and aluminum nitrate nonahydrate are dissolved in methanol at room temperature to obtain solution B, wherein the weight ratio of zinc nitrate hexahydrate, aluminum nitrate nonahydrate and methanol is 1.98:1:43.6.

[0045] (3) The solution A obtained in step (1) is added dropwise to the solution B obtained in step (2) at 47°C and stirring at 1650 r / min. The dropwise rate is 1 drop per second. When the pH of the resulting mixture is 7.8, the dropwise addition ends. The reaction continues for 13 hours, and then a white mixture C is obtained.

[0046] (4) Heat the white mixture C obtained in step (3) to 57°C, add sodium glutamate, and then stir at a speed of 1500 r / min for 6 h to obtain white mixture D. The weight ratio of white mixture C obtained in step (3) to sodium glutamate is 8:0.12.

[0047] (5) Filter the mixture D obtained in step (4) at room temperature. Wash the filtered gel with methanol solvent three times to obtain white gel E. The weight ratio of mixture D to methanol solvent is 1:3.

[0048] (6) Dissolve monosodium glutamate and polyvinyl alcohol in water. The weight ratio of monosodium glutamate, polyvinyl alcohol and water is 0.35:1:90. React at room temperature and with stirring for 1 hour at a stirring speed of 400 r / min. Then add sodium hydroxide to adjust the pH of the solution to 8.5 and continue to react for 1 hour to obtain solution F.

[0049] (7) At 20°C and under stirring conditions, the gel E obtained in step (5) is added to solution F. The stirring speed is 700 r / min. After stirring for 5 hours, a colloidal suspension containing glutamic acid / polyvinyl alcohol-zinc aluminum hydrotalcite is obtained, which is a cosmetic rheology modifier. The weight ratio of solution F to gel E is 1.5:1.

[0050] Example 3

[0051] A cosmetic rheology modifier, the preparation steps of which are as follows:

[0052] (1) Dissolve NaOH in methanol solvent at 50℃ to obtain solution A, wherein the weight ratio of NaOH to methanol is 1:6.6;

[0053] (2) Zinc nitrate hexahydrate and aluminum nitrate nonahydrate are dissolved in methanol at room temperature to obtain solution B, wherein the weight ratio of zinc nitrate hexahydrate, aluminum nitrate nonahydrate and methanol is 2.24:1:45.3;

[0054] (3) The solution A obtained in step (1) is added dropwise to the solution B obtained in step (2) at 50°C and stirring at 1800 r / min. The dropwise rate is 1 drop every 2 seconds. When the pH of the resulting mixture is 8.0, the dropwise addition ends. The reaction continues for 17 h, and then a white mixture C is obtained.

[0055] (4) Heat the white mixture C obtained in step (3) to 60°C, add sodium glutamate, and then stir at a speed of 2000 r / min for 8 hours to obtain white mixture D. The weight ratio of white mixture C obtained in step (3) to sodium glutamate is 10:0.15.

[0056] (5) Filter the mixture D obtained in step (4) at room temperature. Wash the filtered gel with methanol solvent 4 times to obtain white gel E. The weight ratio of mixture D to methanol solvent is 1:3.

[0057] (6) Dissolve monosodium glutamate and polyvinyl alcohol in water with a weight ratio of 0.4:1:100. React at room temperature with stirring for 2 hours at a stirring speed of 600 r / min. Then add sodium hydroxide to adjust the pH of the solution to 9.0 and continue to react for 2 hours to obtain solution F.

[0058] (7) At 22°C and under stirring conditions, the gel E obtained in step (5) is added to solution F. The stirring speed is 800 r / min. After stirring for 7 hours, a colloidal suspension containing glutamic acid / polyvinyl alcohol-zinc aluminum hydrotalcite is obtained, which is a cosmetic rheology modifier. The weight ratio of solution F to gel E is 2:1.

[0059] Example 4

[0060] A cosmetic rheology modifier, the preparation steps of which are as follows:

[0061] (1) Dissolve NaOH in methanol at 53℃ to obtain solution A, wherein the weight ratio of NaOH to methanol is 1:7.0;

[0062] (2) Zinc nitrate hexahydrate and aluminum nitrate nonahydrate are dissolved in methanol at room temperature to obtain solution B, wherein the weight ratio of zinc nitrate hexahydrate, aluminum nitrate nonahydrate and methanol is 2.5:1:46.9;

[0063] (3) The solution A obtained in step (1) is added dropwise to the solution B obtained in step (2) at 53°C and stirring at 2200 r / min. The dropwise rate is 1 drop every 2 seconds. When the pH of the resulting mixture is 8.3, the dropwise addition ends. The reaction continues for 21 h, and then a white mixture C is obtained.

[0064] (4) Heat the white mixture C obtained in step (3) to 63°C, add sodium glutamate, and then stir at a speed of 2500 r / min for 10 h to obtain white mixture D. The weight ratio of white mixture C obtained in step (3) to sodium glutamate is 12:0.18.

[0065] (5) Filter the mixture D obtained in step (4) at room temperature. Wash the filtered gel with methanol solvent 4 times to obtain white gel E. The weight ratio of mixture D to methanol solvent is 1:3.

[0066] (6) Dissolve monosodium glutamate and polyvinyl alcohol in water. The weight ratio of monosodium glutamate, polyvinyl alcohol and water is 0.45:1:110. React at room temperature and with stirring for 2 hours at a stirring speed of 700 r / min. Then add sodium hydroxide to adjust the pH of the solution to 9.5 and continue to react for 2 hours to obtain solution F.

[0067] (7) The gel E obtained in step (5) is added to solution F at 29℃ and under stirring conditions. The stirring speed is 900r / min. After stirring for 9h, a colloidal suspension containing glutamic acid / polyvinyl alcohol-zinc aluminum hydrotalcite is obtained, which is a cosmetic rheology modifier. The weight ratio of solution F to gel E is 2.5:1.

[0068] Example 5

[0069] A cosmetic rheology modifier, the preparation steps of which are as follows:

[0070] (1) Dissolve NaOH in methanol solvent at 55℃ to obtain solution A, wherein the weight ratio of NaOH to methanol is 1:7.4;

[0071] (2) Zinc nitrate hexahydrate and aluminum nitrate nonahydrate are dissolved in methanol at room temperature to obtain solution B, wherein the weight ratio of zinc nitrate hexahydrate, aluminum nitrate nonahydrate and methanol is 2.75:1:48.6.

[0072] (3) The solution A obtained in step (1) is added dropwise to the solution B obtained in step (2) at 55°C and stirring at 3000 r / min. The dropwise rate is 1 drop every 3 seconds. When the pH of the resulting mixture is 8.5, the dropwise addition is stopped. The reaction continues for 24 hours, and then a white mixture C is obtained.

[0073] (4) Heat the white mixture C obtained in step (3) to 65°C, add sodium glutamate, and then stir at a speed of 3000 r / min for 12 h to obtain white mixture D. The weight ratio of white mixture C obtained in step (3) to sodium glutamate is 14:0.21.

[0074] (5) Filter the mixture D obtained in step (4) at room temperature. Wash the filtered gel with methanol solvent 5 times to obtain white gel E, wherein the weight ratio of mixture D to methanol solvent is 1:3.

[0075] (6) Dissolve monosodium glutamate and polyvinyl alcohol in water. The weight ratio of monosodium glutamate, polyvinyl alcohol and water is 0.5:1:120. React at room temperature and with stirring for 3 hours at a stirring speed of 800 r / min. Then add sodium hydroxide to adjust the pH of the solution to 10.0 and continue to react for 3 hours to obtain solution F.

[0076] (7) The gel E obtained in step (5) is added to solution F at 35°C and under stirring conditions. The stirring speed is 1000 r / min. After stirring for 12 h, a colloidal suspension containing glutamic acid / polyvinyl alcohol-zinc aluminum hydrotalcite is obtained, which is a cosmetic rheology modifier. The weight ratio of solution F to gel E is 3:1.

[0077] Comparative Example 6

[0078] The difference between this embodiment and Example 3 is that in this embodiment, methanol solvent is not used in steps (1)-(5), but deionized water is used instead of methanol, and the amount of water is the same as that of methanol. The other preparation steps and reagent amounts are the same as in Example 3. The specific preparation steps are as follows:

[0079] (1) Dissolve NaOH in an aqueous solvent at 50℃ to obtain solution A, wherein the weight ratio of NaOH to water is 1:6.6;

[0080] (2) Zinc nitrate hexahydrate and aluminum nitrate nonahydrate are dissolved in an aqueous solvent at room temperature to obtain solution B, wherein the weight ratio of zinc nitrate hexahydrate, aluminum nitrate nonahydrate and water is 2.24:1:45.3;

[0081] (3) The solution A obtained in step (1) is added dropwise to the solution B obtained in step (2) at 50°C and stirring at 1800 r / min. The dropwise rate is 1 drop every 2 seconds. When the pH of the resulting mixture is 8.0, the dropwise addition ends. The reaction continues for 17 h, and then a white mixture C is obtained.

[0082] (4) Heat the white mixture C obtained in step (3) to 60°C, add sodium glutamate, and then stir at a speed of 2000 r / min for 8 hours to obtain white mixture D. The weight ratio of white mixture C obtained in step (3) to sodium glutamate is 10:0.15.

[0083] (5) Filter the mixture D obtained in step (4) at room temperature, wash the filtered gel with water solvent 4 times to obtain white colloid E, wherein the weight ratio of mixture D to water solvent is 1:3.

[0084] Steps (6) and (7) in this embodiment are the same as steps (6) and (7) in embodiment (3).

[0085] The white mixture C obtained in step (3) of this embodiment was filtered and washed three times with 50 ml of water. The precipitate after washing was dried to constant weight in a vacuum drying oven at 60°C to obtain dried zinc-aluminum hydrotalcite. In Example 3, the mixture C obtained in step (3) was filtered, washed with methanol solvent, and vacuum dried to obtain methoxy zinc-aluminum hydrotalcite. The colloidal substance E obtained in step (5) was vacuum dried to obtain glutamic acid-methoxy zinc-aluminum hydrotalcite. The colloidal suspension of glutamic acid / polyvinyl alcohol-zinc-aluminum hydrotalcite obtained in step (7) was filtered, washed with deionized water, and vacuum dried to obtain glutamic acid / polyvinyl alcohol-zinc-aluminum hydrotalcite. The samples obtained above were ground into powder and then X-ray powder diffraction characterization was performed (X-ray powder diffraction was performed on a Rigaku D / MAX X-ray diffractometer, CuKα (Pipe voltage 40.0 kV, pipe current 30.0 mA), test results are attached. Figure 1 As shown.

[0086] Appendix Figure 1The image shows X-ray powder diffraction patterns of the zinc-aluminum hydrotalcite prepared in step (3) of Comparative Example 6 and the methoxy zinc-aluminum hydrotalcite, glutamic acid-methoxy zinc-aluminum hydrotalcite, and glutamic acid / polyvinyl alcohol-zinc-aluminum hydrotalcite prepared in Example 3 of this invention. Compared to the zinc-aluminum hydrotalcite, the first diffraction peak of the methoxy zinc-aluminum hydrotalcite shifts towards the small-angle diffraction direction. This is because in Example 3, the zinc-aluminum hydrotalcite was prepared in methanol solvent, and the methoxy groups in methanol were grafted onto the layers of the zinc-aluminum hydrotalcite, leading to an increase in the interlayer spacing. Compared to the methoxy zinc-aluminum hydrotalcite, the first diffraction peak of the glutamic acid-methoxy zinc-aluminum hydrotalcite shifts towards the small-angle diffraction direction. This is because negatively charged glutamate ions are embedded into the positively charged interlayer spaces of the zinc-aluminum hydrotalcite, further increasing the interlayer spacing of the glutamic acid-methoxy zinc-aluminum hydrotalcite. Compared to glutamic acid-methoxy zinc-aluminum hydrotalcite, the diffraction peak shape of glutamic acid / polyvinyl alcohol-zinc-aluminum hydrotalcite changed and the position of the first diffraction peak shifted. This is because the negatively charged glutamic acid / polyvinyl alcohol supramolecular complex replaced the glutamate ions and entered the inorganic interlayer. At the same time, the methoxy groups grafted onto the inorganic interlayer were also removed from the interlayer surface during the hydrolysis reaction. This resulted in changes in the interlayer structure of glutamic acid / polyvinyl alcohol-zinc-aluminum hydrotalcite compared to glutamic acid-methoxy zinc-aluminum hydrotalcite.

[0087] Comparative Example 7

[0088] The difference between this embodiment and embodiment 3 is that step (4) is omitted. Instead, in step (5), the white mixture C obtained in step (3) is used instead of the mixture D in step (5) for filtration and washing with methanol four times to obtain a gel-like substance E. Then, the gel-like substance E undergoes the same subsequent steps as in embodiment 3, that is, the reaction between sodium glutamate and zinc aluminum methoxyhydrotalcite is not carried out, and glutamate-zinc aluminum methoxyhydrotalcite is not used in the preparation steps. The other preparation steps and reagent dosages are the same as in embodiment 3.

[0089] Comparative Example 8

[0090] The difference between this embodiment and Example 3 is that this embodiment does not use the glutamic acid / polyvinyl alcohol complex. That is, this embodiment omits step (6), and in step (7) this embodiment, deionized water is used instead of solution F. The other preparation steps and reagent amounts are the same as in Example 3. Step (7) of this embodiment is as follows:

[0091] The gel E obtained in step (5) was added to deionized water with pH 7.0 at 22℃ and under stirring conditions. The stirring speed was 800 r / min. After stirring for 7 hours, a colloidal suspension was obtained, which is a cosmetic rheology modifier. The weight ratio of deionized water to gel E obtained in step (5) was 2:1.

[0092] Comparative Example 9

[0093] The difference between this embodiment and Embodiment 3 is that the weight ratio of solution F to gel E in step (7) of this embodiment is 2:0.8, which is not within the scope of claims (1-3):1, meaning that the amount of gel E used is relatively small. The other preparation steps and reagent amounts are the same as in Embodiment 3.

[0094] Comparative Example 10

[0095] The difference between this embodiment and Embodiment 3 is that the weight ratio of zinc nitrate hexahydrate, aluminum nitrate nonahydrate, and methanol in step (2) of this embodiment is 2.24:0.8:45.3, meaning that the amount of aluminum nitrate used is not within the range of (1.73-2.75):1:(42-48.6) in the weight ratio of magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, and methanol as stated in the claims. The other preparation steps and reagent amounts are the same as in Embodiment 3.

[0096] Application Example 11

[0097] In this embodiment, cosmetic rheology modifiers prepared in Examples 1-5 and rheology modifier samples prepared in Comparative Examples 6-10 are used to prepare cosmetics according to the following steps:

[0098] In an oil-phase reactor, the oily additives are stirred at 85°C and 50 rpm until melted and uniformly mixed. In an emulsification reactor, the emulsifier, chelating agent, rheology modifier, skin moisturizer based on liquid natural rubber, and deionized water are stirred uniformly at 85°C and 50 rpm, with a weight ratio of rheology modifier to skin moisturizer based on liquid natural rubber of 20:100. The materials in the oil-phase reactor are transferred to the emulsification reactor. After the two phases are mixed, homogenization is started at 5000 rpm with continuous stirring. When the temperature drops to 40°C, the fragrance is added to obtain the cosmetic product.

[0099] The oily additives include 2.5 wt% cetearyl alcohol ether-10, 5.0 wt% cetyl / octadecyl alcohol, 3.0 wt% dimethyl silicone oil, 3.0 wt% alkyl benzoate, and 4.0 wt% isopropyl myristate. The emulsifiers include 0.15 wt% carbomer 941, 0.15 wt% xanthan gum, 1.0 wt% stearic acid glycerides, and 1.0 wt% lauryl polyoxyethylene (23) ether. The chelating agent is 0.08 wt% EDTA-2Na; the fragrance includes 0.25 wt% fragrance and 0.1 wt% methyl methacrylate II. The amount of the liquid natural rubber-based skin moisturizer added is 15% of the cosmetic mass; after removing the mass percentage of each component in the system, the remainder is the mass percentage of water.

[0100] In contrast, cosmetics were prepared without any rheology modifiers, following the same steps and reagent dosages, with the weight ratio of rheology modifier to liquid natural rubber-based skin moisturizer being 0:100.

[0101] Application Example 12

[0102] In this embodiment, the cosmetic rheology modifier prepared in Example 3 is used to prepare a cosmetic with a high pseudoplasticity coefficient according to the following steps:

[0103] In an oil phase reactor, the oily additives are stirred at 85°C and 50 r / min until they melt and are mixed evenly. In an emulsification reactor, the emulsifier, chelating agent, cosmetic rheology modifier prepared in steps (1)-(7), skin moisturizer based on liquid natural rubber, and deionized water are stirred evenly at 85°C and 50 r / min. The weight ratio of cosmetic rheology modifier to skin moisturizer based on liquid natural rubber is 15:100. The material in the oil phase reactor is transferred to the emulsification reactor. After the two phases are mixed, the homogenizer is started and homogenized at 5000 r / min. The mixture is stirred continuously. When the temperature drops to 40°C, the fragrance is added to obtain a cosmetic with a high pseudoplasticity coefficient.

[0104] The oily additives include 2.5 wt% cetearyl alcohol ether-10, 5.0 wt% cetyl / octadecyl alcohol, 3.0 wt% dimethyl silicone oil, 3.0 wt% alkyl benzoate, and 4.0 wt% isopropyl myristate.

[0105] The emulsifier comprises 0.15 wt% Carbomer 941, 0.15 wt% xanthan gum, and 2.0 wt% lauryl polyoxyethylene (23) ether.

[0106] The chelating agent is 0.08 wt% EDTA-2Na; the flavoring agent includes 0.25 wt% fragrance and 0.1 wt% Crème de la Mer.

[0107] The amount of the skin moisturizer based on liquid natural rubber added is 10% of the cosmetic mass; after removing the mass percentage of each component in the system, the remainder is the mass percentage of water.

[0108] Application Example 13

[0109] In this embodiment, the cosmetic rheology modifier prepared in Example 3 is used to prepare a cosmetic with a high pseudoplasticity coefficient according to the following steps:

[0110] In an oil phase reactor, the oily additives are stirred at 85°C and 50 r / min until they melt and are mixed evenly. In an emulsification reactor, the emulsifier, chelating agent, cosmetic rheology modifier prepared in steps (1)-(7), skin moisturizer based on liquid natural rubber, and deionized water are stirred evenly at 85°C and 50 r / min. The weight ratio of cosmetic rheology modifier to skin moisturizer based on liquid natural rubber is 25:100. The material in the oil phase reactor is transferred to the emulsification reactor. After the two phases are mixed, the homogenizer is started and homogenized at 5000 r / min. The mixture is stirred continuously. When the temperature drops to 40°C, the fragrance is added to obtain a cosmetic with a high pseudoplasticity coefficient.

[0111] The oily additives include 2.5 wt% cetearyl alcohol ether-10, 5.0 wt% cetyl / octadecyl alcohol, 3.0 wt% dimethyl silicone oil, 3.0 wt% alkyl benzoate, and 4.0 wt% isopropyl myristate.

[0112] The emulsifier comprises 0.15 wt% Carbomer 941, 0.15 wt% xanthan gum, and 2.0 wt% hard fatty acid glycerides.

[0113] The chelating agent is 0.08 wt% EDTA-2Na; the flavoring agent includes 0.25 wt% fragrance and 0.1 wt% Crème de la Mer.

[0114] The amount of the skin moisturizer based on liquid natural rubber added is 20% of the cosmetic mass; after removing the mass percentage of each component in the system, the remainder is the mass percentage of water.

[0115] Application Example 14

[0116] The difference between this embodiment and application embodiment 11 is that in this embodiment, only the cosmetic rheology modifier prepared in embodiment 3 is used to prepare the cosmetic, and the weight ratio of the cosmetic rheology modifier prepared in embodiment 3 to the skin moisturizer based on liquid natural rubber is 12:100, which is outside the scope of the claims (15-25):100, meaning the amount of rheology modifier used is less than the scope of the claims. The other preparation steps and reagent amounts are the same as in embodiment 11.

[0117] Effect Example

[0118] 1. Emulsion stability tests were performed on the liquid samples obtained in Examples 1-10.

[0119] Observe whether the sample will separate into layers within 30 days. If the sample does not separate into layers, it indicates that the liquid is stable and can proceed to the next test. If separation occurs, it indicates that the sample is unstable and is not suitable as a rheology modifier for liquid mulch film. The sample will not proceed to the next test stage. The test results are shown in Table 1-4.

[0120] 2. Rheological tests were performed on the cosmetics prepared in Application Examples 11-14:

[0121] The tests were performed using a rheometer (model MARS60), with the test temperature set at 25℃ and the shear rate ranging from 0.1 to 1000 s⁻¹. -1 The apparent viscosity of the emulsion samples was measured with increasing shear rate and a delay time of 10 s. If the apparent viscosity of the liquid continuously increases with increasing shear rate, the liquid is a dilatant fluid; if the apparent viscosity of the liquid continuously decreases with increasing shear rate, the liquid is a pseudoplastic fluid. The formula for calculating the pseudoplasticity coefficient of a liquid (Reference 2: Cui Bin et al., Basic Properties of Rheology Modifiers for Cosmetics, Fragrance and Flavor Cosmetics, 2021, 12(6), 48-51.) is Equation (1):

[0122] K p = (μ2-μ1)×100% / S (1)

[0123] μ2 represents the shear rate at 0.1 s⁻¹. -1 Viscosity at 500 s, μ1 is the shear rate at 500 s. -1 The viscosity at K is given by S, which is a constant (499.9). p The larger the liquid, the better its shear thinning properties. The test results are shown in Table 1-4.

[0124] 3. The moisture absorption rate of the cosmetics prepared in Application Examples 11-14 was tested. The test method is shown below:

[0125] Accurately weigh the sample and place it in a weighing dish. Then, place the weighing dish in a container containing saturated ammonium sulfate solution at a humidity of RH = 80% and a temperature of 20 ± 0.5℃ for 120 hours to absorb moisture. Next, quickly place the weighing dish in a silica gel desiccator at an ambient temperature of 25 ± 0.5℃. Measure the mass of the sample after 24 hours. Calculate the moisture absorption rate based on the mass change. Evaluate the moisturizing activity by measuring the moisture absorption rate. The moisture absorption rate is calculated using the following formula: Moisture absorption rate = [(Mass of the sample after 24 hours - Initial mass of the sample) / Initial mass of the sample] × 100%. The test results are shown in Tables 1-4.

[0126] 4. The stability properties of the cosmetics prepared in Application Examples 11-14 were tested. The test methods are shown below:

[0127] Sensory testing: Visually inspect the product's properties to check for any abnormalities;

[0128] Heat resistance test: Place the sample in an electric thermostatic incubator at (40±1℃), and after it returns to room temperature, observe whether there are any phenomena such as thinning, discoloration, layering, and hardness changes, in order to judge the heat resistance performance of the sample.

[0129] Cold resistance test: Place the sample in a refrigerator at (-5 to -10℃), and after it returns to room temperature, observe whether there are any phenomena such as thinning, discoloration, layering, and changes in hardness, in order to determine the cold resistance performance of the sample.

[0130] Centrifugation test: Place the sample in a centrifuge and test it at a speed of (2000~4000) r / min to observe the separation and stratification of the sample.

[0131] The results of the cosmetic stability test are shown in Table 1-4.

[0132] 5. The actual moisturizing properties of cosmetics prepared using the rheology modifier prepared in Example 3 in Application Examples 11-14 were tested using the following methods:

[0133] The water content of the stratum corneum was determined using a Skicon 200 (IBS Ltd) high-frequency conductivity meter. Subjects were healthy women without skin diseases. The experimental conditions required constant temperature and humidity during the testing period: temperature (30±2℃), relative humidity 30%–50%. The test area was the forearm skin, a 5cm × 5cm area. The results of the moisturizing performance test are shown in Table 5.

[0134] 6. As can be seen from Table 1, the cosmetic rheology modifiers prepared in Examples 1-5 did not exhibit stratification within 30 days, indicating that the suspensions prepared in Examples 1-5 are stable. In contrast, the liquid sample prepared in Comparative Example 6 showed precipitation, i.e., solid-liquid stratification occurred on day 1. This is because Comparative Example 6 did not use methanol as a solvent, but rather water. The zinc-aluminum hydrotalcite synthesized in the aqueous solvent is a crystalline solid with high crystal order; the inorganic layers are orderly aggregated and stacked together, resulting in large grains. This can be seen from its X-ray powder diffraction pattern (see attached table). Figure 1a) It was confirmed that the highly ordered stacking of these inorganic zinc-aluminum hydrotalcite layers made it difficult to suspend in solution, instead existing as a precipitate. This ultimately led to precipitation and solid-liquid stratification in the cosmetic prepared from the sample of Comparative Example 6, which did not meet the requirements for cosmetic quality. Therefore, the sample prepared from Comparative Example 6 could not be used as a rheology modifier for cosmetics, and it was not subjected to subsequent testing. The liquid samples (or rheology modifiers) prepared from Comparative Examples 7-10 did not exhibit solid-liquid stratification, indicating that the liquid samples prepared in these examples were also stable. This is because comparative examples 7-11 used methanol as a solvent during the preparation process. Methanol molecules, under the action of sodium hydroxide, formed M-OCH3 groups with the metal hydroxyl groups (M-OH) on the zinc-aluminum layered double hydroxide (LDH) plates. When the zinc-aluminum LDH grafted with -OCH3 groups encounters an aqueous solvent, the M-OCH3 groups on the plates are easily hydrolyzed in water to generate M-OH and release CH3OH molecules. This hydrolysis reaction is rapid and violent. The energy released by the reaction can instantly depolymerize the zinc-aluminum LDH plates, and the zinc-aluminum LDH becomes very small colloidal particles. These tiny colloidal particles can be stably suspended in the aqueous solution without producing solid-liquid stratification.

[0135] As can be seen from the results in Table 2, in Application Example 11, the viscosity of the cosmetic prepared from the rheology modifiers obtained in Examples 1-5 decreased with increasing shear rate, exhibiting pseudoplastic fluid properties (see Appendix). Figure 4 The rheological curves corresponding to Examples 1, 2, 4, and 5 are similar to those of Example 3. Their pseudoplasticity coefficients are 71%-75%, which is at least 39% higher than that of cosmetics containing liquid rubber without any rheology modifier. This means that the rheology modifiers obtained in Examples 1-5 significantly improve the pseudoplasticity of cosmetics containing liquid rubber, enhancing their shear-thinning properties. Simultaneously, the 24-hour moisture absorption rate of cosmetics prepared with the rheology modifiers obtained in Examples 1-5 is at least 8% higher than that of cosmetics without any rheology modifier. This is because the glutamic acid / polyvinyl alcohol-zinc aluminum hydrotalcite intercalation complex in the rheology modifier has a certain degree of hydrophilicity, thereby improving the moisture absorption of the cosmetics prepared with the rheology modifier. The sensory indicators, thermal stability, freezing stability, and centrifugal stability of the cosmetics prepared with the rheology modifiers obtained in Examples 1-5 are all normal, meeting the requirements for cosmetic stability.

[0136] The results in Table 3 are analyzed as follows: The pseudoplasticity coefficient of the cosmetic emulsion prepared from the sample obtained in Comparative Example 7 is 42%, which is 33% lower than that of the cosmetic emulsion in Example 3. This is because the difference between Comparative Example 7 and Example 3 is that the interlayer ion exchange reaction between monosodium glutamate and zinc aluminum methoxyhydrotalcite is not used, that is, glutamate-zinc aluminum methoxyhydrotalcite is not used in the preparation steps. If glutamic acid is embedded between the layers of methoxy zinc aluminum hydrotalcite, the interlayer spacing of the methoxy zinc aluminum hydrotalcite can be increased, reducing the interaction between the layers. This facilitates the subsequent embedding of the glutamic acid-polyvinyl alcohol supramolecular complex between the zinc aluminum hydrotalcite layers. Therefore, in Comparative Example 7, since glutamic acid-methoxy zinc aluminum hydrotalcite was not prepared, the glutamic acid-polyvinyl alcohol complex is also difficult to embed between the zinc aluminum hydrotalcite layers in subsequent steps. Consequently, the glutamic acid / polyvinyl alcohol-zinc aluminum hydrotalcite intercalation organic-inorganic complex was not prepared, making it difficult to limit the extension range of the liquid natural rubber molecular chains and reduce the end-chain distance of the liquid natural rubber molecular chains. As a result, the effects of reducing the viscosity of the cosmetic emulsion containing liquid natural rubber molecules and increasing its pseudoplasticity coefficient cannot be achieved.

[0137] The pseudoplasticity coefficient of the cosmetic emulsion prepared from the sample obtained in Comparative Example 8 was 40%, which was 35% lower than that of the cosmetic emulsion in Example 3. The difference between Comparative Example 8 and Example 3 is that Comparative Example 8 did not use the glutamic acid / polyvinyl alcohol supramolecular complex, and therefore did not obtain the glutamic acid / polyvinyl alcohol-zinc aluminum hydrotalcite intercalation complex. Consequently, there were no polyvinyl alcohol molecular chains suspended outside the hydrotalcite layer to clamp the liquid natural rubber molecules end to end, and thus the extension range of the liquid natural rubber molecular chains could not be limited or the end distance reduced. Therefore, the sample obtained in Comparative Example 8 could not achieve the effect of further reducing the viscosity of the cosmetic emulsion containing liquid natural rubber molecules and increasing its pseudoplasticity coefficient.

[0138] The pseudoplasticity coefficient of the cosmetic emulsion prepared from the sample obtained in Comparative Example 9 was 52%, which was 23% lower than that of the cosmetic emulsion in Example 3. The difference between Comparative Example 9 and Example 3 is that the weight ratio of solution F to gel E in step (7) was 2:0.8, which is not within the scope of claims (1-3):1, that is, the amount of glutamic acid-zinc-aluminum hydrotalcite was smaller. This correspondingly led to a smaller content of glutamic acid / polyvinyl alcohol-zinc-aluminum hydrotalcite intercalation complex in the rheology modifier, that is, there was not enough effective ingredient to limit the extension range and end distance of the liquid natural rubber molecular chains. Therefore, the sample obtained in Comparative Example 9 was not significant in reducing the viscosity of the cosmetic emulsion containing liquid natural rubber molecules and increasing its pseudoplasticity coefficient.

[0139] The pseudoplasticity coefficient of the cosmetic emulsion prepared from the sample obtained in Comparative Example 10 was 59%, which was 16% lower than that of the cosmetic emulsion in Example 3. The difference between Comparative Example 10 and Example 3 is that the weight ratio of zinc nitrate hexahydrate, aluminum nitrate nonahydrate, and methanol in step (2) is 2.24:0.8:45.3, that is, the amount of aluminum nitrate is less than the weight ratio of zinc nitrate hexahydrate, aluminum nitrate nonahydrate, and methanol in the claims (1.73-2.75):1:(42-48.6). This will result in too few positive charges on the zinc-aluminum hydrotalcite inorganic layer, which will affect the amount of intercalated glutamic acid / polyvinyl alcohol complex. In other words, if the content of intercalated glutamic acid / polyvinyl alcohol complex is too low, the effect of the glutamic acid / polyvinyl alcohol-zinc-aluminum hydrotalcite intercalation complex in restricting the extension range of liquid natural rubber molecular chains and reducing their end distance will be weakened. Therefore, the sample obtained in Comparative Example 10 is not significant in reducing the viscosity of cosmetic emulsions containing liquid natural rubber molecules and increasing their pseudoplasticity coefficient. Of all the samples listed in Table 3, the cosmetic prepared with the rheology modifier obtained in Example 3 had the highest pseudoplasticity coefficient and 24-hour moisture absorption rate.

[0140] Table 4 shows the pseudoplasticity, moisture absorption, and stability test results of cosmetics prepared using the rheology modifier obtained in Example 3 in Application Examples 11-14. In Application Examples 11-14, the weight ratio of the cosmetic rheology modifier obtained in Example 3 to the liquid natural rubber-based skin moisturizer differed. The results show that in Application Examples 11-13, when the weight ratio of the cosmetic rheology modifier to the liquid natural rubber-based skin moisturizer was within the scope of the claims, the pseudoplasticity and 24-hour moisture absorption of the prepared cosmetics were similar, and the stability test results were all satisfactory. In comparison, the pseudoplasticity of the cosmetic in Application Example 14 was 61%, which is 14% lower than the pseudoplasticity of the cosmetic prepared using the sample from Example 3 in Application Example 11. This is because in Comparative Application Example 14, the weight ratio of the cosmetic rheology modifier to the skin moisturizer based on liquid natural rubber was 12:100, which is outside the scope of the claims (15-25):100. That is, the amount of rheology modifier used was less than the scope of the claims, which correspondingly weakened the effect of the glutamic acid / polyvinyl alcohol-zinc aluminum hydrotalcite layered composite as an active ingredient in limiting the extension range of the liquid natural rubber molecular chains and reducing their end distance. Therefore, the cosmetic prepared in Comparative Application Example 14 was not significant in reducing the viscosity of cosmetic emulsions containing liquid natural rubber molecules and increasing their pseudoplasticity coefficient.

[0141] Table 5 shows the results of the actual moisturizing performance of cosmetics prepared using the rheology modifier prepared in Example 3 in Application Examples 11-13 over time. The results show that the moisturizing rate of cosmetics prepared using the rheology modifier prepared in Example 3 in Application Examples 11-13 is at least 20% higher than that of cosmetics without any rheology modifier at all time points (3h, 6h, 12h, and 24h). This indicates that cosmetics prepared with the rheology modifier prepared according to the present invention have a high pseudoplasticity coefficient, making them easier to spread on the skin surface, and thus exhibiting better moisturizing performance in practical applications (compared to cosmetics prepared without rheology modifier). Table 1 shows the stability of the liquids obtained in Examples 1-5 and Comparative Examples 6-10, evaluated by recording whether the liquids exhibited stratification within 30 days.

[0142]

[0143] Table 2 shows the pseudoplasticity, moisture absorption, and stability test results of cosmetics prepared using the rheology modifiers obtained in Examples 1-5 and cosmetics without rheology modifiers in Application Example 11.

[0144]

[0145]

[0146] Table 3 shows the pseudoplasticity coefficient, moisturizing properties, and stability test results of cosmetics prepared using the rheology modifiers obtained in Example 3 and Comparative Examples 7-10 in Application Example 11.

[0147]

[0148] Table 4 shows the pseudoplasticity coefficient, moisturizing properties, and stability test results of cosmetics prepared using the rheology modifier obtained in Example 3 in Application Examples 11-14.

[0149]

[0150]

[0151] Table 5 shows the actual moisturizing performance results of cosmetics prepared using the rheology modifier prepared in Example 3 in Application Examples 11-13, with the cosmetic prepared in Application Example 11 without any rheology modifier as the control group.

[0152]

Claims

1. A method for preparing a cosmetic rheology modifier, comprising the following steps: (1) Dissolve NaOH in methanol at 45-55℃ to obtain solution A, wherein, The weight ratio of NaOH to methanol is 1:(5.8-7.4); (2) Zinc nitrate hexahydrate and aluminum nitrate nonahydrate are dissolved in methanol at room temperature to obtain solution B, wherein the weight ratio of zinc nitrate hexahydrate, aluminum nitrate nonahydrate and methanol is (1.73-2.75):1:(42-48.6); (3) Add the solution A obtained in step (1) dropwise to the solution B obtained in step (2) at 45-55℃ and stirring at 1500-3000r / min. The dropwise rate is 1 drop every 1-3 seconds. When the pH of the resulting mixture is 7.5-8.5, the dropwise addition ends. Continue the reaction for 10-24 hours, and then obtain a white mixture C. (4) Heat the white mixture C obtained in step (3) to 55-65℃, add sodium glutamate, and then stir at a speed of 1000-3000 r / min for 3-12 h to obtain white mixture D, wherein the weight ratio of white mixture C obtained in step (3) to sodium glutamate is (7-14):(0.1-0.21); (5) Filter the mixture D obtained in step (4) at room temperature. Wash the filtered gel with methanol solvent 3-5 times to obtain white gel E, wherein the weight ratio of mixture D to methanol solvent is 1:

3. (6) Dissolve monosodium glutamate and polyvinyl alcohol in water, with a weight ratio of monosodium glutamate, polyvinyl alcohol and water of (0.3-0.5):1:(80-120). React at room temperature with stirring for 1-3 hours at a stirring speed of 300-800 r / min. Then add sodium hydroxide to adjust the pH of the solution to 8.0-10.0 and continue the reaction for 1-3 hours to obtain solution F. (7) Add the gel E obtained in step (5) to solution F at 18-35℃ and under stirring conditions. The stirring speed is 500-1000r / min. After stirring for 2-12h, a colloidal suspension containing glutamic acid / polyvinyl alcohol-zinc aluminum hydrotalcite is obtained, which is a cosmetic rheology modifier. The weight ratio of solution F to gel E is (1-3):

1.

2. The preparation method according to claim 1, characterized in that... In step (2), the weight ratio of zinc nitrate hexahydrate, aluminum nitrate nonahydrate, and methanol is 2.24:1:45.

3.

3. The preparation method according to claim 1, characterized in that... In step (4), the weight ratio of the white mixture C obtained in step (3) to monosodium glutamate is (10-12):(0.15-0.18).

4. The preparation method according to claim 1, characterized in that... In step (6), the weight ratio of sodium glutamate, polyvinyl alcohol and water is 0.4:1:

100.

5. The preparation method according to claim 1, characterized in that... In step (7), the weight ratio of solution F to gel E is 2:

1.

6. A cosmetic rheology modifier used in the preparation of cosmetics with a high pseudoplasticity coefficient, characterized in that, The raw materials used in the preparation method include: the cosmetic rheology modifier according to any one of claims 1-5 and the skin moisturizer based on liquid natural rubber, and the preparation steps are as follows: In an oil-phase reactor, the oily additives are stirred at 85°C and 50 r / min until melted and mixed evenly. In an emulsification reactor, the emulsifier, chelating agent, cosmetic rheology modifier, skin moisturizer based on liquid natural rubber, and deionized water are stirred evenly at 85°C and 50 r / min. The weight ratio of the cosmetic rheology modifier to the skin moisturizer based on liquid natural rubber is (15-25):

100. The materials in the oil-phase reactor are transferred to the emulsification reactor. After the two phases are mixed, homogenization is started at 5000 r / min with continuous stirring. When the temperature drops to 40°C, the fragrance is added to obtain a cosmetic with a high pseudoplasticity coefficient.

7. The method for preparing a cosmetic with a high pseudoplasticity coefficient according to claim 6, characterized in that... The oily additives include 2.5 wt% cetearyl alcohol ether-10, 5.0 wt% cetyl / octadecyl alcohol, 3.0 wt% dimethyl silicone oil, 3.0 wt% alkyl benzoate, and 4.0 wt% isopropyl myristate; the emulsifiers include 0.15 wt% carbomer 941, 0.15 wt% xanthan gum, 2.0 wt% hard fatty acid glycerides (and) lauryl polyoxyethylene (23) ether; the chelating agent is 0.08 wt% EDTA-2Na; and the fragrances include 0.25 wt% fragrance and 0.1 wt% methoxyl II.

8. The preparation method according to claim 6, characterized in that... The amount of the skin moisturizer based on liquid natural rubber added is 10-20% of the cosmetic mass.

9. The preparation method according to claims 1-8, wherein, The water used is deionized water.

10. The application of the high pseudoplasticity coefficient cosmetic as described in claims 6-8 in cosmetics.

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