Microcapsule, method for preparing the same, and microencapsulated cosmetic

Abstract

This application relates to a microcapsule and its preparation method, as well as microcapsule cosmetics, belonging to the field of cosmetic technology. The preparation method includes: mixing a film-forming agent, a thickener, and water, and heating to obtain a first aqueous phase; mixing a viscosity control agent with water to obtain a second aqueous phase A and a second aqueous phase B; mixing the first and second aqueous phases A to obtain a pre-prepared aqueous phase; mixing oils and active substances to obtain a first oil phase; mixing oils and surfactants to obtain a second oil phase; subjecting the pre-prepared aqueous phase, the first oil phase, and the second oil phase to a first stirring reaction at a first stirring speed, simultaneously adding the second aqueous phase B during the first stirring reaction to obtain an emulsion system; adjusting the stirring speed to a second stirring speed for a second stirring reaction, allowing the mixture to stand and separate into layers, and removing the lower layer to obtain microcapsules; wherein the second stirring speed is less than the first stirring speed. The preparation method of this application can effectively reduce the degradation rate of active substances in the microcapsules.

Description

Technical Field

[0001] This application relates to the field of cosmetic technology, and in particular to a microcapsule and its preparation method, and microcapsule cosmetics. Background Technology

[0002] Vitamin A is commonly found in animal livers, especially in saltwater fish and mammalian livers. In the cosmetics industry, because both epidermal keratinocytes and dermal fibroblasts possess retinol receptors, the skin is considered one of the main vitamin A-responsive tissues, with vitamin A participating in cell proliferation, differentiation, and apoptosis. The vitamin A family includes retinaldehyde, retinoic acid, carotenoids, retinol, and other derivatives. Based on its ability to promote keratinocyte metabolism and stimulate collagen production in dermal fibroblasts, vitamin A is a widely used and popular active ingredient in skincare products for whitening, anti-oxidation, and anti-aging purposes.

[0003] Hydroxypinazone retinyl ester (HPR), as a novel retinol derivative, exhibits similar skincare effects to retinol while being less irritating, thus gaining market favor. Nevertheless, many retinol and its derivative products on the market currently neglect the characteristics of the raw materials during encapsulation, especially under conditions such as heating, which accelerates the degradation of retinol and its derivatives. Furthermore, traditional encapsulation processes often require the use of toxic reagents such as ether and chloroform, increasing safety risks. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this application is to provide a microcapsule and its preparation method, and a microcapsule cosmetic, so as to reduce the degradation rate of active substances and increase the safety of the product.

[0005] In a first aspect, embodiments of this application provide a method for preparing microcapsules, comprising: mixing a film-forming agent, a thickener, and water, heating to obtain a first aqueous phase; mixing a viscosity control agent with water to obtain a second aqueous phase A and a second aqueous phase B; mixing the first aqueous phase and the second aqueous phase A to obtain a pre-prepared aqueous phase; mixing an oil and an active substance to obtain a first oil phase; mixing an oil and a surfactant to obtain a second oil phase; performing a first stirring reaction on the pre-prepared aqueous phase, the first oil phase, and the second oil phase at a first stirring speed, simultaneously adding the second aqueous phase B during the first stirring reaction to obtain an emulsion system; adjusting the stirring speed to a second stirring speed to perform a second stirring reaction, allowing the mixture to stand and separate into layers, removing the lower layer to obtain microcapsules; wherein the second stirring speed is less than the first stirring speed.

[0006] This application first mixes film-forming agents, thickeners, and water, then heats the mixture to form an aqueous phase. Next, oils and active substances are mixed to form an oil phase. Emulsification is then achieved through appropriate stirring and temperature control. This reverse emulsification method forms a water-in-oil emulsion, which can reduce the formation of bubbles in the emulsion, improve the stability of the emulsion, and prevent phase separation. It can also promote the formation of a more uniform microcapsule structure, achieve uniform encapsulation of active substances, and effectively reduce the degradation rate of active substances in the microcapsules. The pre-prepared aqueous phase allows for effective interaction between its components, enabling the active substances to be effectively encapsulated within microcapsules during emulsification. The pre-prepared aqueous phase, the first oil phase, and the second oil phase are stirred at a first stirring speed. Simultaneously, the second aqueous phase B is added. Controlling the stirring speed during this process ensures thorough mixing of the phases, forming a stable emulsion system. It also promotes uniform distribution of microcapsules and better controls their particle size, facilitating the preparation of smaller microcapsules (10–150 μm). The stirring speed is then reduced for a second stirring reaction to promote stratification and microcapsule sedimentation. This process also maximizes the preservation of microcapsule structural integrity, reducing the risk of breakage or deformation and improving microcapsule quality and stability. After final settling and stratification, the separated upper layer is the second oil phase, which can be recycled, reducing costs and resource waste, making it more environmentally friendly. Furthermore, this encapsulation process does not use toxic reagents commonly found in traditional encapsulation systems (such as ether and chloroform).

[0007] In some embodiments of this application, the mass ratio of the first aqueous phase and the second aqueous phase A in the pre-formed aqueous phase is (8-18):(95-105).

[0008] Pre-preparing the aqueous phase allows for better encapsulation of active substances within microcapsules and improves microcapsule formation. Limiting the mass ratio of the first aqueous phase to the second aqueous phase A within the range of (8–18):(95–105) enables effective interaction between the components in the aqueous phase, enhancing the likelihood of effective encapsulation of active substances during emulsification. This results in more complete encapsulation of active ingredients within the microcapsules, reducing their loss. Furthermore, within this ratio range, film-forming agents and thickeners dissolve sufficiently, improving the strength and integrity of the microcapsule membrane and ensuring stable morphology of the microcapsules in subsequent operations. Adding the oil phase later further enhances the efficiency of the emulsification reaction, thereby improving the yield and quality of the microcapsules.

[0009] In some embodiments of this application, during the first stirring reaction, a second aqueous phase B is added simultaneously, wherein the mass ratio of the second aqueous phase B to the mass of the first aqueous phase in the pre-prepared aqueous phase is 1:(3-13).

[0010] By simultaneously adding the second aqueous phase B during the stirring process, rapid mixing of the components can be promoted, forming a uniform emulsion system, thereby improving the stability and uniformity of the microcapsules. Furthermore, the mass ratio of the second aqueous phase B to the first aqueous phase in the pre-formed aqueous phase is 1:(3-13). A higher proportion of the first aqueous phase provides sufficient film-forming agent and thickener, improving the strength and integrity of the microcapsule membrane. By adjusting the amount of the second aqueous phase B added, the particle size and morphology of the microcapsules can be controlled within a certain range to meet the needs of different products.

[0011] In some embodiments of this application, in the first stirring reaction, the first stirring speed is 215-225 r / min and the stirring time is 10-20 min; and / or, in the second stirring reaction, the second stirring speed is 95-105 r / min and the stirring time is 25-35 min.

[0012] The first stirring reaction (215–225 r / min) rapidly mixes the liquids, enhancing the interaction between the oil and water phases and forming finer droplets, thereby improving the uniformity and stability of the emulsion. It also effectively disperses the active ingredients in the oil phase, ensuring uniform distribution within the microcapsules and reducing the loss of active ingredients. Limiting the stirring time of the first reaction to 10–20 min facilitates the thorough emulsification process. Further reducing the stirring speed for the second stirring reaction prevents excessive shear stress on the microcapsule membrane during formation, thus maintaining its structural integrity. Limiting the stirring time of the second reaction to 25–35 min allows for sufficient sedimentation and stratification of the microcapsules, enhancing the degree of cross-linking and improving their stability during storage and use.

[0013] In some embodiments of this application, the film-forming agent includes xanthan gum. Xanthan gum can form a robust film structure on the surface of microcapsules, effectively protecting the internal active ingredients and preventing them from being oxidized or degraded. Furthermore, xanthan gum exhibits good biocompatibility and safety.

[0014] In some embodiments of this application, the thickener includes sodium alginate. Sodium alginate can significantly increase the viscosity of the aqueous phase, prevent phase separation during emulsification, and improve the uniformity of the microcapsules. Furthermore, the gel formed by sodium alginate in water can enhance the strength of the microcapsule membrane, further improving the stability of the microcapsules.

[0015] In some embodiments of this application, the viscosity control agent includes calcium chloride.

[0016] Adding calcium chloride can optimize the rheological properties of the emulsion system, balance viscosity, and promote the smooth progress of the emulsification process. Simultaneously, calcium chloride can react with sodium alginate to form a cross-linked structure, further enhancing the strength and stability of the microcapsule membrane.

[0017] In some embodiments of this application, the mass percentage of the film-forming agent in the first aqueous phase is 0.1% to 3%.

[0018] Setting the mass percentage of the film-forming agent within the range of 0.1% to 3% can effectively form a strong membrane structure, optimize the stability of microcapsules, and reduce irritation.

[0019] In some embodiments of this application, the mass percentage of the thickener in the first aqueous phase is 0.2% to 1%.

[0020] Setting the mass percentage of the thickener within the range of 0.2% to 1% can effectively thicken the aqueous phase, optimize the structural stability of the microcapsules, and reduce irritation.

[0021] In some embodiments of this application, the viscosity control agent has a mass percentage of 0.15% to 0.5% in the second aqueous phase.

[0022] Setting the viscosity control agent by mass percentage in the range of 0.15% to 0.5% can effectively adjust the viscosity of the aqueous phase, enhance emulsion stability, improve film-forming performance, and reduce the risk of bubble formation.

[0023] In some embodiments of this application, the oils include one or more of caprylic acid, capric acid, triglyceride succinate, meadowfoam seed oil, isononyl isononanoate, triglyceride (ethylhexanoate), squalane, mineral oil, decyl cocoate, and ethylhexyl palmitate.

[0024] These oils are all skin-friendly ingredients with good compatibility and strong moisturizing ability. Heating these oils in microcapsules can improve the application feel and smoothness of microcapsule products, as well as enhance their skin compatibility and moisturizing performance, while also increasing the stability of the microcapsule formula.

[0025] In some embodiments of this application, the active substances include one or more of Centella asiatica extract, hydroxypinazone retinate, Lithospermum erythrorhizon extract, oil-soluble recombinant collagen, ascorbyl palmitate, sea buckthorn extract, and plant oils.

[0026] The interaction of these ingredients can achieve multiple skincare benefits, such as moisturizing, repairing, anti-aging, and anti-oxidation, meeting consumers' demand for high-efficiency skincare products.

[0027] In some embodiments of this application, the HLB value of the surfactant is >14.

[0028] Selecting liquid surfactants with an HLB value greater than 14 can significantly enhance emulsification ability and improve product stability.

[0029] In some embodiments of this application, the surfactant includes one or more of Tween 20, Tween 60, and Tween 80.

[0030] The surfactants mentioned above all provide good emulsifying properties and mildness, and can also enhance product stability.

[0031] In some embodiments of this application, the mass percentage of the active substance in the first oil phase is 10-95%.

[0032] In some embodiments of this application, the mass percentage of surfactant in the second oil phase is 0.2% to 4.8%.

[0033] Setting the surfactant mass percentage within the range of 0.2% to 4.8% can effectively optimize emulsification, improve formulation stability, mildness, and safety.

[0034] Secondly, embodiments of this application provide a microcapsule prepared by the above-described preparation method.

[0035] Secondly, embodiments of this application provide a microcapsule cosmetic, including the microcapsules described above. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a visual image of the microcapsules prepared in Example 7 of this application;

[0038] Figure 2 This is a microscopic image of the microcapsules prepared in Example 7 of this application;

[0039] Figure 3 This is a visual image of the microcapsules prepared in Example 9 of this application;

[0040] Figure 4 This is a microscopic image of the microcapsules prepared in Example 9 of this application;

[0041] Figure 5 This is a visual image of the microcapsules prepared in Example 1 of this application;

[0042] Figure 6 This is a microscopic image of the microcapsules prepared in Example 1 of this application;

[0043] Figure 7This is a visual image of the microcapsules prepared in Example 6 of this application;

[0044] Figure 8 This is a microscopic image of the microcapsules prepared in Example 6 of this application;

[0045] Figure 9 This is a graph showing the degradation test results of the microcapsules prepared in Example 6 of this application. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0047] The following is a detailed description of a microcapsule, its preparation method, and a microcapsule cosmetic according to an embodiment of this application.

[0048] This application provides a microcapsule, the preparation method of which includes the following steps:

[0049] (1) Preparation of the first aqueous phase

[0050] The film-forming agent, thickener, and water are mixed, stirred, and heated to 85°C to dissolve the raw materials evenly, thus obtaining the first aqueous phase.

[0051] The film-forming agent includes xanthan gum; the thickener includes sodium alginate.

[0052] In the first aqueous phase, the mass percentage of the film-forming agent is 0.1–3%; the mass percentage of the thickener is 0.2–1%.

[0053] A film-forming agent concentration of 0.1% to 3% can effectively form a tough film structure. A good film structure can effectively isolate the external environment and prevent the intrusion of moisture and oxygen, thereby protecting the internal active ingredients. Moreover, within this concentration range, it can reduce skin irritation. It can also form good interactions with other components such as thickeners and viscosity control agents, enhancing the stability of the entire system.

[0054] A thickener concentration of 0.2% to 1% can effectively increase the viscosity of the aqueous phase. By increasing the viscosity of the aqueous phase, it can help stabilize the emulsion system, prevent the separation of the oil and water phases, and improve the uniformity of the microcapsules. By forming a more uniform network structure in the microcapsule membrane, it can effectively improve the mechanical strength of the membrane and reduce the risk of breakage during storage and use. Moreover, within this concentration range, it can reduce skin irritation.

[0055] In this embodiment of the application, the first aqueous phase further includes a humectant and a preservative. For example, the humectant includes, but is not limited to, glycerin and 1,3-butanediol; the preservative includes, but is not limited to, phenoxyethanol.

[0056] The humectant comprises 4-8% by mass in the first aqueous phase, and the preservative comprises 0.1-1% by mass in the first aqueous phase. For example, the mass percentage of the humectant in the first aqueous phase includes, but is not limited to, 4%, 5%, 6%, 7%, and 8%; and the mass percentage of the preservative in the first aqueous phase includes 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, and 1%.

[0057] In this embodiment of the application, the first aqueous phase also includes active substances. For example, the active substances include, but are not limited to, Centella asiatica extract and Lithospermum erythrorhizon extract.

[0058] (2) Preparation of the second aqueous phase

[0059] The viscosity control agent was mixed with water to obtain a second aqueous phase A and a second aqueous phase B.

[0060] The viscosity control agent includes calcium chloride.

[0061] In the second aqueous phase, the viscosity control agent has a mass percentage of 0.15–0.5%.

[0062] A viscosity control agent concentration of 0.15% to 0.5% can effectively adjust the viscosity of the aqueous phase. By adjusting the viscosity of the aqueous phase, the separation rate between the oil and water phases can be reduced, phase separation and precipitation can be prevented, and the uniformity and stability of the microcapsules can be improved. At the same time, it can also help form a more robust membrane structure, enhance the protective ability of the microcapsules, and effectively encapsulate the internal active ingredients.

[0063] (3) Preparation of pre-aqueous phase

[0064] The first aqueous phase obtained in step (1) and the second aqueous phase A obtained in step (2) are mixed to obtain a pre-prepared aqueous phase.

[0065] In the pre-formed aqueous phase, the mass ratio of the first aqueous phase to the second aqueous phase A is (8-18):(95-105)0. As an example, the mass ratio of the first aqueous phase to the second aqueous phase A includes, but is not limited to, 8:95, 8:96, 8:97, 8:98, 8:99, 8:100, 8:101, 8:102, 8:103, 8:104, 8:105, 10:95, 11:96, 11:97, 11:98, 11:99, 11:100, 11:101, 11:102, 11:103, 11:104, 11:105, 13:95, 13:96, 13:97, 13:98, and 13:99. 9, 13:100, 13:101, 13:102, 13:103, 13:104, 13:105, 15:95, 15:96, 15:97, 15:98, 15:99, 15:100, 15:101, 15:102, 15:103, 15:104, 15:105, 18:95, 18:96, 18:97, 18:98, 18:99, 18:100, 18:101, 18:102, 18:103, 18:104, 18:105.

[0066] (4) Preparation of the first oil phase

[0067] The oil and active substance are mixed to obtain the first oil phase.

[0068] The oils and fats include, but are not limited to, one or more of the following: caprylic acid, capric acid, triglyceride succinate, meadowfoam seed oil, isononyl isononanoate, triglyceride (ethylhexanoate), squalane, mineral oil, decyl cocoate, and ethylhexyl palmitate.

[0069] In the embodiments of this application, the active substances include, but are not limited to, one or more of the following: Centella asiatica extract, hydroxypinazone retinate, Lithospermum erythrorhizon extract, oil-soluble recombinant collagen, ascorbyl palmitate, sea buckthorn extract, and plant oils.

[0070] Centella asiatica extract has excellent repairing and anti-inflammatory effects, promoting wound healing and enhancing the skin barrier function. Comfrey extract is rich in natural antioxidants, helping to soothe the skin and improve uneven skin tone and dullness. Hydroxypinazone retinyl ester promotes collagen synthesis, reduces fine lines and wrinkles, and improves skin elasticity. Oil-soluble recombinant collagen helps improve skin firmness and smoothness, strengthening the skin's structural support. Ascorbyl palmitate has significant antioxidant effects, protecting the skin from free radical damage and promoting skin radiance and evenness. Sea buckthorn extract is rich in vitamins C and E and various antioxidants, protecting the skin from environmental stress and aging.

[0071] In the first oil phase, the mass percentage of the active substance is 10% to 95%. For example, the mass percentage of the active substance includes, but is not limited to, 10%, 14%, 18%, 20%, 24%, 28%, 30%, 35%, 37%, 40%, 45%, 50%, 55%, 60%, 62%, 66%, 70%, 78%, 80%, 85%, 90%, and 95%. It should be noted that the mass percentage of the active substance can be adjusted according to the matrix of the active substance, and this application does not limit this adjustment.

[0072] (5) Preparation of the second oil phase

[0073] The oil and surfactant are mixed to obtain the second oil phase.

[0074] The oils and fats include, but are not limited to, one or more of the following: caprylic acid, capric acid, triglyceride succinate, meadowfoam seed oil, isononyl isononanoate, triglyceride (ethylhexanoate), squalane, mineral oil, decyl cocoate, and ethylhexyl palmitate.

[0075] The surfactant is a liquid surfactant with an HLB value greater than 14. For example, the surfactant includes, but is not limited to, one or more of Tween 20, Tween 60, and Tween 80.

[0076] Surfactants with an HLB value > 14 exhibit very high hydrophilicity. This strong hydrophilicity allows them to mix effectively with the aqueous phase, making them suitable for oil-in-water (W / O) or water-in-oil (O / W) emulsion systems, enhancing emulsion stability. Furthermore, high HLB surfactants typically possess stronger emulsifying capabilities, effectively mixing the oil and aqueous phases to form finer, more uniform droplets, thereby improving the stability and uniformity of the emulsion product. In addition, high HLB surfactants are generally milder, less likely to irritate the skin, and can improve the fluidity and spreadability of emulsions, as well as enhance the product's spreadability and penetration on the skin surface, allowing active ingredients to penetrate the skin more effectively.

[0077] In the second oil phase, the surfactant has a mass percentage of 0.2% to 4.8%. As an example, the mass percentage of the surfactant includes, but is not limited to, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, and 4.8%.

[0078] Surfactant concentrations of 0.2% to 4.8% can effectively promote the emulsification of oil and water phases. They can also reduce surface tension and form a stable emulsion film, enhancing the uniformity of the product during storage and use. Furthermore, surfactant concentrations within this range can reduce skin irritation.

[0079] (6) Preparation of emulsion system

[0080] The pre-prepared aqueous phase, the first oil phase, and the second oil phase are subjected to a first stirring reaction at a first stirring speed. During the first stirring reaction, the second aqueous phase B is added simultaneously to obtain an emulsion system.

[0081] The first stirring speed is 215–225 r / min, and the stirring time is 10–20 min. For example, the first stirring speed includes, but is not limited to, 215 r / min, 216 r / min, 217 r / min, 218 r / min, 219 r / min, 220 r / min, 221 r / min, 222 r / min, 223 r / min, 224 r / min, and 225 r / min; the stirring time includes, but is not limited to, 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, 18 min, 19 min, and 20 min.

[0082] In this embodiment, the mass ratio of the second aqueous phase B to the mass of the first aqueous phase in the pre-formed aqueous phase is 1:(3-13). As an example, the mass ratio of the second aqueous phase B to the mass of the first aqueous phase in the pre-formed aqueous phase includes, but is not limited to, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, and 1:13.

[0083] (7) Sedimentation and stratification to obtain microcapsules

[0084] The stirring speed was adjusted to the second stirring speed to carry out the second stirring reaction. After standing and separating into layers, the lower layer was removed to obtain microcapsules; wherein, the second stirring speed is less than the first stirring speed.

[0085] In this embodiment, the second stirring speed is 95–105 r / min, and the stirring time is 25–35 min. For example, the second stirring speed includes, but is not limited to, 95 r / min, 96 r / min, 97 r / min, 98 r / min, 99 r / min, 100 r / min, 101 r / min, 102 r / min, 103 r / min, 104 r / min, and 105 r / min; the stirring time includes, but is not limited to, 25 min, 26 min, 27 min, 28 min, 29 min, 30 min, 31 min, 32 min, 33 min, 34 min, and 35 min.

[0086] In this preparation method, the first step is to mix the film-forming agent, thickener, and water, and then heat the mixture to form a first aqueous phase. This process not only allows the film-forming agent and thickener to dissolve fully but also enhances the structural strength of the microcapsule membrane and improves the overall stability of the microcapsules. The film-forming agent helps to form a robust membrane structure, while the thickener increases the viscosity of the system, preventing phase separation that may occur during emulsification.

[0087] Next, the viscosity control agent is mixed with water to obtain a second aqueous phase A and a second aqueous phase B. This step allows for precise adjustment of the viscosity of the aqueous phases to optimize the emulsification effect. By flexibly adjusting the properties of the aqueous phases, the uniformity of emulsification can be effectively improved, enhancing the stability of the emulsion system under different process conditions.

[0088] Subsequently, the first aqueous phase is mixed with the second aqueous phase A to obtain a pre-prepared aqueous phase. At this point, the oil and active substance are mixed to form the first oil phase, which effectively protects the active substance. By mixing the active substance with the oil, the risk of degradation in the aqueous environment can be effectively reduced, thereby maintaining the stability and effectiveness of the active substance.

[0089] During the emulsification process, the pre-prepared aqueous phase, the first oil phase, and the second oil phase undergo an emulsification reaction at a first stirring speed, while the second aqueous phase B is added simultaneously. This process utilizes different stirring speeds to promote uniform distribution of microcapsules and good particle size control. Setting the first stirring speed helps to fully mix the phases and form a stable emulsion system.

[0090] Next, the stirring speed is adjusted to a second stirring speed for a second stirring reaction. This stage of stirring, at a lower speed than the first, promotes the sedimentation and stratification of the microcapsules. By using a slower stirring speed, the structural integrity of the microcapsules can be maintained to the greatest extent, reducing the risk of rupture or deformation and improving the quality and stability of the microcapsules.

[0091] Finally, after settling and separating the layers, the lower layer is removed to obtain microcapsules. In this process, settling allows the microcapsules to settle effectively, facilitating efficient recovery, reducing operational complexity, and improving production efficiency.

[0092] The features and performance of this application will be further described in detail below with reference to the embodiments.

[0093] Example 1

[0094] This embodiment provides a microcapsule, the preparation method of which includes the following steps:

[0095] (1) Preparation of the first aqueous phase

[0096] 0.2g xanthan gum, 1g sodium alginate, 6g glycerin, 5g 1,3-butanediol, 0.6g phenoxyethanol, 0.8g Centella asiatica extract and water (total reaction volume 100g, water as a replenishing medium) were mixed, stirred and heated to 85°C to dissolve the above raw materials evenly, thus obtaining the first aqueous phase.

[0097] (2) Preparation of the second aqueous phase

[0098] 0.2g of calcium chloride was mixed with water (the total reaction system was 100g, with water as a replenishing medium) to obtain the second aqueous phase. To facilitate subsequent preparation, the second aqueous phase was divided into two parts with different masses, namely the second aqueous phase A and the second aqueous phase B. That is to say, the second aqueous phase A and the second aqueous phase B are the same substance, only with different masses.

[0099] (3) Preparation of pre-aqueous phase

[0100] The first aqueous phase obtained in step (1) and the second aqueous phase A obtained in step (2) are mixed evenly at a mass ratio of 13:100 to obtain a pre-prepared aqueous phase.

[0101] (4) Preparation of the first oil phase

[0102] 3.55g of caprylic / capric / succinic acid triglyceride, 1.25g of hydroxypinazone retinate, and 0.2g of comfrey extract were mixed to obtain the first oil phase.

[0103] It should be noted that caprylic / capric / succinic triglyceride is a common raw material name in the cosmetics industry, and the manufacturer is: Oleo Chemicals, Germany.

[0104] (5) Preparation of the second oil phase

[0105] Meadowfoam seed oil (total reaction system of 100g, with meadowfoam seed oil as the finishing medium) was mixed with 2.4g Tween 20 to obtain the second oil phase.

[0106] (6) Preparation of emulsion system

[0107] The pre-prepared aqueous phase, the first oil phase, and the second oil phase were subjected to a first stirring reaction at 220 r / min for 15 min. During the first stirring reaction, the second aqueous phase B, which was 8 times the mass of the first aqueous phase in the pre-prepared aqueous phase, was added simultaneously to obtain an emulsion system.

[0108] (7) Sedimentation and stratification to obtain microcapsules

[0109] The stirring speed was adjusted to 99 r / min for the second stirring reaction. After stirring for 30 min, the stirrer was turned off, and the mixture was allowed to stand for 1 h. The layers were collected and the lower layer was removed to obtain microcapsules.

[0110] The preparation methods and raw material ratios of the remaining embodiments and comparative examples are basically the same as those of Example 1, except that some raw material ratios or parameter steps are different. For details of the differences, please refer to Table 1.

[0111] Table 1

[0112]

[0113]

[0114] Comparative Example 1

[0115] This comparative example is basically the same as Example 1, except that the pre-prepared aqueous phase is not made in advance.

[0116] This comparative example provides a microcapsule, the preparation method of which includes the following steps:

[0117] (1) Preparation of the first aqueous phase

[0118] 0.2g xanthan gum, 1g sodium alginate, 6g glycerin, 5g 1,3-butanediol, 0.6g phenoxyethanol, 0.8g Centella asiatica extract and water (total reaction volume 100g, water as a replenishing medium) were mixed, stirred and heated to 85°C to dissolve the above raw materials evenly, thus obtaining the first aqueous phase.

[0119] (2) Preparation of the second aqueous phase

[0120] 0.2g of calcium chloride was mixed with water (the total reaction system was 100g, with water as a replenishing medium) to obtain the second aqueous phase.

[0121] (3) Preparation of the first oil phase

[0122] 3.55g of caprylic / capric / succinic acid triglyceride, 1.25g of hydroxypinazone retinate, and 0.2g of comfrey extract were mixed to obtain the first oil phase.

[0123] It should be noted that caprylic / capric / succinic acid triglyceride is a common raw material name in the cosmetics industry, and the manufacturer is: Oleo Chemicals, Germany.

[0124] (4) Preparation of the second oil phase

[0125] Meadowfoam seed oil (total reaction system of 100g, with meadowfoam seed oil as the finishing medium) was mixed with 2.4g Tween 20 to obtain the second oil phase.

[0126] (5) Preparation of emulsion system

[0127] The first aqueous phase, the first oil phase, and the second oil phase prepared above were subjected to a first stirring reaction at 220 r / min for 15 min. During the first stirring reaction, the second aqueous phase with a mass of 8 times that of the first aqueous phase was added simultaneously to obtain an emulsion system.

[0128] (6) Sedimentation and stratification to obtain microcapsules

[0129] The stirring speed was adjusted to 99 r / min for the second stirring reaction. After stirring for 30 min, the stirrer was turned off, and the mixture was allowed to stand for 1 h. The layers were collected and the lower layer was removed to obtain microcapsules.

[0130] Comparative Example 2

[0131] This comparative example is basically the same as Example 1, except that there is no second oil phase.

[0132] This comparative example provides a microcapsule, the preparation method of which includes the following steps:

[0133] (1) Preparation of the first aqueous phase

[0134] 0.2g xanthan gum, 1g sodium alginate, 6g glycerin, 5g 1,3-butanediol, 0.6g phenoxyethanol, 0.8g Centella asiatica extract and water (total reaction volume 100g, water as a replenishing medium) were mixed, stirred and heated to 85°C to dissolve the above raw materials evenly, thus obtaining the first aqueous phase.

[0135] (2) Preparation of the second aqueous phase

[0136] 0.2g of calcium chloride was mixed with water (the total reaction system was 100g, with water as a replenishing medium) to obtain the second aqueous phase. To facilitate subsequent preparation, the second aqueous phase was divided into two parts with different masses, namely the second aqueous phase A and the second aqueous phase B. That is to say, the second aqueous phase A and the second aqueous phase B are the same substance, only with different masses.

[0137] (3) Preparation of pre-aqueous phase

[0138] The first aqueous phase obtained in step (1) and the second aqueous phase A obtained in step (2) are mixed evenly at a mass ratio of 13:100 to obtain a pre-prepared aqueous phase.

[0139] (4) Preparation of the first oil phase

[0140] 3.55g of caprylic / capric / succinic acid triglyceride, 1.25g of hydroxypinazone retinate, and 0.2g of comfrey extract were mixed to obtain the first oil phase.

[0141] It should be noted that caprylic / capric / succinic triglyceride is a common raw material name in the cosmetics industry, and the manufacturer is: Oleo Chemicals, Germany.

[0142] (5) Preparation of emulsion system

[0143] The pre-prepared aqueous phase and the first oil phase were subjected to a first stirring reaction at 220 r / min for 15 min. During the first stirring reaction, the second aqueous phase B, which was 8 times the mass of the first aqueous phase in the pre-prepared aqueous phase, was added simultaneously to obtain an emulsion system.

[0144] (6) Sedimentation and stratification to obtain microcapsules

[0145] The stirring speed was adjusted to 99 r / min for the second stirring reaction. After stirring for 30 min, the stirrer was turned off, and the mixture was allowed to stand for 1 h. The layers were collected and the lower layer was removed to obtain microcapsules.

[0146] Comparative Example 3

[0147] This comparative example is basically the same as Example 1, except that the stirring speed is not reduced and the second stirring reaction is continued.

[0148] This comparative example provides a microcapsule, the preparation method of which includes the following steps:

[0149] (1) Preparation of the first aqueous phase

[0150] 0.2g xanthan gum, 1g sodium alginate, 6g glycerin, 5g 1,3-butanediol, 0.6g phenoxyethanol, 0.8g Centella asiatica extract and water (total reaction volume 100g, water as a replenishing medium) were mixed, stirred and heated to 85°C to dissolve the above raw materials evenly, thus obtaining the first aqueous phase.

[0151] (2) Preparation of the second aqueous phase

[0152] 0.2g of calcium chloride was mixed with water (the total reaction system was 100g, with water as a replenishing medium) to obtain the second aqueous phase. To facilitate subsequent preparation, the second aqueous phase was divided into two parts with different masses, namely the second aqueous phase A and the second aqueous phase B. That is to say, the second aqueous phase A and the second aqueous phase B are the same substance, only with different masses.

[0153] (3) Preparation of pre-aqueous phase

[0154] The first aqueous phase obtained in step (1) and the second aqueous phase A obtained in step (2) are mixed evenly at a mass ratio of 13:100 to obtain a pre-prepared aqueous phase.

[0155] (4) Preparation of the first oil phase

[0156] 3.55g of caprylic / capric / succinic acid triglyceride, 1.25g of hydroxypinazone retinate, and 0.2g of comfrey extract were mixed to obtain the first oil phase.

[0157] It should be noted that caprylic / capric / succinic triglyceride is a common raw material name in the cosmetics industry, and the manufacturer is: Oleo Chemicals, Germany.

[0158] (5) Preparation of the second oil phase

[0159] Meadowfoam seed oil (total reaction system of 100g, with meadowfoam seed oil as the finishing medium) was mixed with 2.4g Tween 20 to obtain the second oil phase.

[0160] (6) Preparation of emulsion system

[0161] The pre-prepared aqueous phase, the first oil phase, and the second oil phase were subjected to a first stirring reaction at 220 r / min for 15 min. During the first stirring reaction, the second aqueous phase B, which was 8 times the mass of the first aqueous phase in the pre-prepared aqueous phase, was added simultaneously to obtain an emulsion system.

[0162] (7) Sedimentation and stratification to obtain microcapsules

[0163] Maintain a stirring speed of 220 r / min and continue stirring for 30 min. Then turn off the stirrer, let it stand for 1 h, collect the layers, remove the lower layer, and obtain microcapsules.

[0164] Experimental Example 1

[0165] This experiment is to observe the preparation and molding of the microcapsules obtained in Examples 1-10 and Comparative Examples 1-3. The preparation conditions include sedimentation rate, yield, whether the active material is completely encapsulated, and whether there is rupture, floating oil, coagulation, or adhesion to the wall.

[0166] The standards are defined as follows:

[0167] Good shaping: The particles are round and well-encapsulated under a microscope.

[0168] Poor forming: The particles are not full or round, or there is agglomeration, and the microparticle core is not well wrapped with grease under the microscope.

[0169] Incomplete formation: The particles cannot form a spherical shape.

[0170] Cracks: The presence of floating oil, and under a microscope, the microparticle core is not properly coated with grease.

[0171] Agglomeration: The film shell of the oil core aggregates into clumps (reference). Figure 1 , Figure 2 )

[0172] Adhesion to the cup wall: When the outer phase film of the oil core agglomerates into clumps, flocculent / clump-like substances adhere to the cup wall (see reference). Figure 1 )

[0173] Oil float: Oil on the surface of the matrix is ​​visible to the naked eye and rises to the surface due to its density.

[0174] Rapid settling: After settling is complete, the microcapsule particles can be observed to settle immediately with the naked eye.

[0175] Slow sedimentation: Microcapsule sedimentation was observed only 2 hours after the settling period was completed.

[0176] Bead yield: The final total mass of microcapsules / total mass of raw materials x 100% = bead yield. A bead yield greater than 60% is considered high, and a yield less than 30% is considered low.

[0177] Please refer to Table 2 for the detection results of the microcapsules prepared in Examples 1-10 and Comparative Examples 1-3 above.

[0178] Table 2

[0179]

[0180]

[0181] As shown in Table 2, in Examples 5 and 7-10, particles agglomerated or broke down, failing to completely encapsulate the microcapsules. In contrast, the microcapsules prepared in Examples 1-4 and Example 6 of this application were well-formed, with the microcapsules prepared in Example 6 having a larger particle size (>150 μm).

[0182] Comparing Examples 1 and 2 reveals that the surfactant content affects the settling speed. Higher Tween 20 content results in a slower settling rate. However, when the Tween 20 content is below 0.2% (e.g., 0.1% in Example 7), agglomeration and adhesion to the walls occur. Therefore, a surfactant content between 0.2% and 4.8% achieves a more ideal settling speed and bead yield. Similarly, comparing the preparations in Examples 1 and 11 shows that sodium alginate concentration is also a factor affecting the settling speed. The settling speed of the 1% sodium alginate aqueous matrix is ​​faster and the bead yield is higher than that of the 0.55% matrix. Furthermore, Example 8 demonstrates that when the sodium alginate content is below 0.2%, agglomeration and easy breakage occur. In addition, the microcapsules prepared in Example 11 were observed to have a particle size concentrated in the range of <50 μm under an optical electron microscope; while the microcapsules prepared in Example 1 were observed to have a particle size between 50 and 150 μm. This result indicates that the concentration of sodium alginate affects the particle size of the microcapsules under this process.

[0183] Figure 1 This is a visual observation image of the microcapsules prepared in Example 7; Figure 2 Microscopic image of the microcapsules prepared in Example 7; Figure 3 This is a visual observation image of the microcapsules prepared in Example 9; Figure 4 Microscopic image of the microcapsules prepared in Example 9; Figure 5 This is a visual observation image of the microcapsules prepared in Example 1; Figure 6 Microscopic image of the microcapsules prepared in Example 1; Figure 7 This is a visual observation image of the microcapsules prepared in Example 6; Figure 8 This is a microscopic image of the microcapsules prepared in Example 6; please refer to... Figures 1-8 .

[0184] from Figure 1 and Figure 2 It can be seen that in Example 7, when the surfactant content was <0.2%, aggregation and adhesion to the walls occurred, and similar situations occurred in Examples 8 and 10 (not shown); in Example 9, when the oil content was as high as 50g, floating oil appeared, and microscopic observation revealed poor molding (e.g. Figure 3 and Figure 4 ).from Figure 5 and Figure 6 It can be seen that the particle size of the microcapsules prepared in Example 1 is 10–150 μm; from Figure 7 and Figure 8 It can be seen that the microcapsules prepared in Example 6 are well formed, and the microcapsules prepared in Example 6 have a large particle size (>150μm).

[0185] Experimental Example 2

[0186] This experiment will test the stability of the microcapsules prepared in Examples 1-10 and Comparative Examples 1-3 at high temperature, low temperature, and room temperature. The processing parameters are as follows: room temperature (25℃, 3 months), high temperature (45℃, 3 months), and low temperature (-18℃, 3 months).

[0187] Stability is defined as a state in which the product's form and appearance remain the same as before testing.

[0188] Please refer to Table 3 for the test results above.

[0189] Table 3

[0190]

[0191]

[0192] Table 3 shows that Examples 7-10 exhibited varying degrees of coagulation or oil floating problems at room temperature, indicating that the content of Tween 20, sodium alginate, calcium ions, and encapsulated oils all affect the stability of the system. Meanwhile, Comparative Examples 1 and 2 show that process operation has a significant impact on the system. In Comparative Example 1, the lack of a pre-prepared aqueous phase resulted in low consistency, leading to incomplete encapsulation of active substances within the microcapsules. In Comparative Example 2, removing the second oil phase only resulted in an unstable gel suspending the oil, failing to yield microcapsules. In Comparative Example 3, failing to reduce the stirring speed during the second stirring reaction would break the still-reacting particles, leading to poor microcapsule formation and surface oil floating.

[0193] Experimental Example 3

[0194] In this experiment, the microcapsules prepared in Examples 1, 5, 6, and 11 were filtered, washed, and dried, and then placed in the following serums and cream bases for testing. Please refer to Table 4 for the ratio of serums and cream bases.

[0195] Table 4

[0196]

[0197]

[0198] I. The preparation method of the serum is as follows:

[0199] S11. Mix the raw materials of phase A1 and heat to 80°C, keep warm for 20 minutes, and set aside;

[0200] S12. Homogenize phase A1 (8000 r / min) for 2 min;

[0201] S13. Add phase A2 to the material from step S12, stir and cool to below 45°C, then add phase C;

[0202] S14. Continue stirring and cooling to 38°C before discharging. Cool to room temperature.

[0203] II. Preparation methods of ointments and creams:

[0204] S21. Mix the raw materials of phase A1 and heat to 80°C, keep warm for 20 minutes, and set aside;

[0205] S22. Mix the raw materials of phase B, heat to 80°C, keep warm for 20 minutes and stir until dissolved and uniform, set aside;

[0206] S23. Homogenize phase A1 (8000 r / min) for 1 min, then slowly add phase B to phase A1 and homogenize (8000 r / min) for 1 min.

[0207] S24. Add phase A2 to the material from step S23, stir and cool to below 45°C, then add phase C;

[0208] S25. Continue stirring and cooling to 38°C before discharging. Cool to room temperature.

[0209] III. Skin feel and stability test results

[0210] Skin feel test: The microcapsules prepared in Examples 1, 5, 6 and 11 were added to the corresponding serums and creams to prepare products. Then, 0.15g of each product was taken and applied to the back of the subject's hand, and the product was spread in a circular motion until absorbed. A skin feel evaluation questionnaire was then filled out.

[0211] Stability testing: The microcapsules prepared in Examples 1, 5, 6, and 11 were respectively formulated into corresponding serums and creams. Then, three parallel samples of each product were placed at: room temperature (25°C, 3 months), high temperature (45°C, 3 months), and low temperature (-18°C, 3 months). Definition of stability: The product is considered stable if it maintains the same form and appearance as before the test.

[0212] Please refer to Table 5 for details of the above skin feel and stability tests.

[0213] Table 5

[0214]

[0215] The serum and cream exhibited high viscosity, while the control group's serum and cream had viscosities of 32,000 and 46,850 mPa·s, respectively. A common problem with microbead encapsulation systems is the viscosity of the matrix, which is prone to breakage at high viscosity (viscosity > 30,000 mPa·s). However, the examples demonstrated good stability in the aforementioned high-viscosity serum and cream, with no breakage or other issues observed during stirring.

[0216] As shown in Table 5, the skin feel of Examples 11 and 1 remained largely unchanged, indicating that 0.55–1% sodium alginate had little impact on the skin feel. However, comparing Examples 1 and 5 revealed that higher calcium ion concentrations resulted in higher microcapsule hardness; a granular texture was perceptible at a calcium ion concentration of 0.6%, therefore, the calcium ion concentration in this process system should not exceed 0.5%. Furthermore, comparing Example 6 showed that microcapsules containing 30% oil significantly improved the moisturizing feel of serums and creams.

[0217] Test Example 4

[0218] This experimental example will test the degradability of the microcapsules prepared in Example 6. The standard method is room temperature degradation, with increased temperature considered as accelerated degradation treatment. The microcapsules were placed in a constant temperature incubator for accelerated degradation at 50°C, and separated using HPLC with UV detection. Qualitative analysis was based on retention time, and quantitative analysis on peak area. The content of encapsulated and unencapsulated hydroxypinazone retinate after a certain time was calculated using a standard curve method to calculate a comparative degradation curve. The mobile phase was methanol (A), and the mobile phase was trichloroacetic acid aqueous solution (B), with a flow rate of 0.8 mL / min, a detection wavelength of 325 nm, and an injection volume of 10 μl.

[0219] Degradability test results as follows Figure 9 As shown, from Figure 9 It can be seen that after two months (at 50°C), the degradation rate of unencapsulated retinol derivatives (HPR) exceeded 50%; while the degradation rate was significantly reduced after encapsulation. These test results indicate that the microencapsulation preparation process provided in this application can effectively delay the degradation of HPR.

[0220] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. A process for the preparation of microcapsules, characterized in that, The application relates to a preparation method of a microcapsule. The film-forming agent, the thickening agent and water are mixed and heated to obtain a first water phase; The viscosity control agent is mixed with water to obtain a second water phase A and a second water phase B respectively; the first water phase and the second water phase A are mixed to obtain a pre-prepared water phase; the mass ratio of the first water phase to the second water phase A in the pre-prepared water phase is (8-18):(95-105); the thickening agent comprises sodium alginate; the viscosity control agent comprises calcium chloride; The oil and the active substance are mixed to obtain a first oil phase; the oil and the surfactant are mixed to obtain a second oil phase; the surfactant comprises one or more of Tween 20, Tween 60 and Tween 80; The pre-prepared water phase, the first oil phase and the second oil phase are subjected to a first stirring reaction at a first stirring speed, and the second water phase B is synchronously added during the first stirring reaction to obtain an emulsified system; the mass ratio of the second water phase B to the first water phase in the pre-prepared water phase is 1:(3-13), the first stirring speed is 215-225 r / min, and the stirring time is 10-20 min; The stirring speed is adjusted to a second stirring speed to perform a second stirring reaction, and the lower layer is taken after static layering to obtain the microcapsule. The second stirring speed is less than the first stirring speed.

2. The production method according to claim 1, characterized by, In the second stirring reaction, the second stirring speed is 95-105 r / min, and the stirring time is 25-35 min.

3. The production method according to any one of claims 1 or 2, characterized in that, The film-forming agent comprises xanthan gum.

4. The production method according to claim 3, characterized by, In the first water phase, the mass percentage of the film-forming agent is 0.1-3%; Optionally, in the first water phase, the mass percentage of the thickening agent is 0.2-1%; Optionally, in the second water phase, the mass percentage of the viscosity control agent is 0.15-0.5%.

5. The production method according to any one of claims 1 or 2, characterized by, The oil comprises one or more of caprylic acid, capric acid, glyceryl trisuccinate, white pool seed oil, isononyl isononanoate, glyceryl tris(ethylhexanoate), squalane, mineral oil, decyl cocoate and ethylhexyl palmitate; Optionally, the active substance comprises one or more of centella asiatica extract, hydroxyl pinacolone retinoate, comfrey extract, oil-soluble recombinant collagen, ascorbyl palmitate, sea buckthorn extract and plant oil; Optionally, the HLB value of the surfactant is greater than 14.

6. The preparation method according to claim 5, characterized in that, In the first oil phase, the mass percentage of the active substance is 10-95%; Optionally, in the second oil phase, the mass percentage of the surfactant is 0.2-4.8%.

7. A microcapsule, characterized in that, The preparation method is prepared according to any one of claims 1-6.

8. A microencapsulated cosmetic, characterized by, The microcapsule is prepared according to claim 7.

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