High-hydrophobicity mica-cinnamyl aldehyde composition as well as preparation method and application thereof

Abstract

The invention discloses a high-hydrophobicity mica-cinnamyl aldehyde composition as well as a preparation method and application thereof, and belongs to the technical field of fine chemical engineering and composite materials. The technical problem to be solved is to solve the problems of high total dosage of a modifier, high raw material cost, no sunscreen property and the like. According to the technical scheme, the preparation method is characterized by comprising the following steps: mixing gamma-aminopropyltriethoxysilane, water and mica to obtain slurry A; the slurry A is stirred for 20-40 min at the temperature of 60-110 DEG C; n-octyl triethoxy silane and dodecyl triethoxy silane are mixed with the slurry A, and slurry B is obtained; stirring the slurry B at 70 to 90 DEG C for 20 to 40 minutes; mixing ammonia water with the slurry B to obtain slurry C; the slurry C is stirred for 1-2 h at the temperature of 125-135 DEG C, and modified mica is obtained; and mixing cinnamyl aldehyde with the modified mica to obtain the sunscreen high-hydrophobicity mica-cinnamyl aldehyde composition.

Description

Technical Field

[0001] This invention relates to the fields of fine chemicals and composite materials, and more specifically, to a highly hydrophobic mica-cinnamaldehyde composition, its preparation method, and its application. Background Technology

[0002] Powder raw materials are widely used in cosmetics, especially in color cosmetics, beauty cosmetics, and sunscreen cosmetics. The main purpose of using powders in cosmetics is to penetrate the surface of the skin, achieving various beautifying effects such as brightening skin tone and concealing wrinkles. Cosmetic powder raw materials are classified into coloring pigments, white pigments, extender pigments, and pearlescent pigments. Among them, extender pigments include inorganic powders, organic powders, and natural powders. Inorganic powders are more commonly used in cosmetics, mainly including mica, talc, kaolin, silica, and alumina, generally serving functions such as concealing, smoothing, oil absorption, spreading, and sun protection. Mica, in particular, has strong adhesion and good covering power and dispersibility; it also possesses a moderate gloss and a soft feel, making it well-suited for addition to cosmetic formulations to improve product texture and appearance, thus its widespread use in color cosmetics. However, natural mica contains hydrophilic hydroxyl groups and other structures on its surface, making it prone to aggregation and exhibiting poor compatibility with polymers, hindering its dispersion in organic media. Furthermore, its poor compatibility, lack of waterproofing and sweatproofing, results in short-lasting makeup and limits its application in color cosmetics. To improve this situation, surface modification of mica powder plays a crucial role. Through surface modification, the properties of mica can be improved, enhancing its water resistance, oleophilicity, compatibility, stability, dispersibility, and adhesion, thus better meeting the needs of color cosmetic applications and consumer demands.

[0003] Mica, a commonly used inorganic powder in cosmetics, possesses a certain UV absorption capacity. However, its weak UV protection solely through physical scattering is insufficient to meet the practical needs of sunscreen cosmetics. Small-molecule sunscreen agents can be stably loaded onto the surface of hydrophobic mica powder through specific reactions, creating a combined powder with both water resistance and UV absorption capabilities. This combined powder not only addresses the issues of volatility and high irritation associated with small-molecule sunscreen agents but also endows mica powder with UV protection and water / sweat-resistant properties, meeting the cosmetic industry's demand for multifunctional powders. It can be applied to products such as sunscreen foundations and loose sunscreen powders, significantly enhancing product performance.

[0004] There are two main methods for modifying powder surfaces: physical and chemical methods. Chemical methods primarily involve surface chemical modifiers and mechanochemical modification, with surface chemical modifiers being the most common. Currently, commonly used surface modifiers for fillers containing high levels of silica, such as quartz powder, kaolin, and mica, include coupling agents, silicone oils, and surfactants. Coupling agents are bifunctional substances capable of simultaneously undergoing physical adsorption or chemical interaction with both inorganic material surfaces and organic matrices. Based on their chemical structure and functional group type, they can be classified into silanes, titanates, aluminates, etc. Among these, silane coupling agents are the most representative surface chemical modifiers. They exhibit a high degree of chemical bonding with the hydroxyl groups on the surface of mica particles, demonstrating excellent modification effects on mica and enabling it to achieve good compatibility with organic materials.

[0005] Relevant patent documents retrieved:

[0006] This patent, published in China (CN118078655A) on January 14, 2025, discloses a highly hydrophobic cosmetic-grade mica material and its preparation method. The preparation method includes the following steps: dispersing mica in DMF, then mixing it with a silane coupling agent mixture, followed by reflux heating; mixing the system with water and reflux heating to modify the mica; and finally filtering, washing, and drying to obtain the highly hydrophobic cosmetic-grade mica material. This invention uses silane coupling agent KH550 as the main modifier, combined with at least one of octyltriethoxysilane and dodecyltriethoxysilane, and controls the reaction temperature, the amount of water, and the amount of DMF used to achieve excellent synergistic hydrophobic modification. Compared with single or other silane coupling agent combinations, the hydrophobic modification effect is better.

[0007] Relevant non-patent literature retrieved: This master's thesis from Jilin University, titled "Study on the Preparation of Modified Sericite and Biomass Carbon Quantum Dots Using Silane Coupling Agent (KH550)," published on May 1, 2023, discloses γ-aminopropyltriethoxysilane (KH550), an amino-based silane coupling agent with abundant nitrogen- and oxygen-containing groups, commonly used for hydrophobic modification of sericite. However, in recent years, the modification effect of KH550 on mica using existing methods needs improvement, and its application areas need further expansion. Although silane coupling agents can form stable chemical bonds with the hydroxyl groups on the mica surface, existing reports show that mica modified with a single silane coupling agent cannot achieve complete hydrophobicity, limiting its practical application in cosmetic systems.

[0008] The prior art represented by the aforementioned documents has at least the following unresolved technical problems or defects: As mentioned above, existing technologies have only improved the hydrophobicity of mica, but have not made any technological improvements to its ultraviolet absorption properties (sunscreen properties).

[0009] Cinnamaldehyde (CA) is a natural aromatic aldehyde, an unsaturated aldehyde with a benzene ring, carbon-carbon double bonds, and a conjugated aldehyde group structure. This conjugated system endows it with characteristic absorption properties in the ultraviolet (UV) region. The aldehyde group in cinnamaldehyde can rapidly undergo a Schiff base reaction with an amino group under mild conditions, forming a composition based on reversible imine bonds. Since cinnamaldehyde possesses UV absorption properties and the ability to form Schiff bonds with amino groups, if the amino groups contained in KH550 grafted onto mica are utilized to undergo a Schiff base reaction to form a composition based on reversible imine bonds, and then loaded onto hydrophobically modified mica, it can impart a certain degree of auxiliary UV shielding function to mica, making it suitable for use in sunscreen cosmetics.

[0010] While synergistic modification with multiple modifiers can optimize the hydrophobicity and organic compatibility of mica, issues remain, such as high total modifier usage and high raw material costs. More effective mica surface hydrophobic modification processes need to be explored. Furthermore, mica without functional components relies solely on its own physical scattering for its sun protection capabilities, resulting in weak sun protection and incomplete UV coverage, which fails to meet the application requirements of sunscreen cosmetics. Therefore, methods such as loading small-molecule sunscreen agents are needed to further enhance its application value.

[0011] Currently, there are few reports on the technology of functionalizing highly hydrophobic mica with cinnamaldehyde. Existing mica modification technologies cannot simultaneously achieve high hydrophobicity and sun protection functions; existing cinnamaldehyde loading technologies are difficult to effectively combine with mica powder and cannot simultaneously achieve hydrophobicity, dispersibility, stability, and functional synergy. Therefore, there is an urgent need to develop a mica-cinnamaldehyde composition and its preparation method that combines high hydrophobicity, good dispersibility, and good sun protection performance to overcome the above-mentioned shortcomings of existing technologies and expand its application in fields such as cosmetics, sunscreens, antibacterial coatings, and functional composite materials. Summary of the Invention

[0012] The purpose of this invention is to provide: A highly hydrophobic mica-cinnamaldehyde composition, its preparation method and application, and related technologies are disclosed to address technical problems such as high total modifier usage, high raw material costs, and lack of sun protection properties, or combinations thereof.

[0013] Terminology Explanation: Unless otherwise defined, all technical terms in this document have the same meanings as commonly understood by one of ordinary skill in the art to which the subject matter of the claims pertains. Unless otherwise stated, all patents, patent inventions, and publications cited in this document are incorporated herein by reference in their entirety. If multiple definitions exist for terms in this document, the definitions in this chapter shall prevail.

[0014] It should be understood that the above brief description and the following detailed description are exemplary and for illustrative purposes only, and do not limit the subject matter of the invention in any way. In this invention, the singular is used in conjunction with the plural unless otherwise specifically stated. It should also be noted that, unless otherwise stated, the use of “or” or “or” means “and / or”. Furthermore, the use of the term “comprising” and other forms such as “including,” “containing,” and “contains” are not limiting.

[0015] The definitions of standard chemical terms can be found in the reference "Pharmacopoeia of the People's Republic of China (2020 Edition), China Medical Science and Technology Press: May 2020: 1st Edition."

[0016] Unless otherwise stated, conventional methods within the scope of the art, such as mixing, heating, dispersing, stirring, and dripping, shall be used.

[0017] Unless specifically defined herein, the use of all commercially available products herein employs standard techniques. For example, it may be carried out using the manufacturer's instructions for use with the kit, or in accordance with methods known in the art or the description of this invention. The techniques and methods described herein can generally be implemented according to conventional methods well known in the art, based on the descriptions in the various summary and more specific documents cited and discussed in this specification.

[0018] The terms “optional / arbitrary” or “optionally / arbitrarily” mean that the event or situation described below may or may not occur, including both the occurrence and non-occurrence of the event or situation.

[0019] As used in this article, "mixing" refers to the process of uniformly distributing two or more components through manipulation to achieve consistent component content. For example, in pharmaceutics, mixing involves combinations of solid-solid, solid-liquid, or liquid-liquid operations to ensure the homogeneity of the final product. Mixing can be achieved through stirring, shaking, sonication, homogenization, grinding, etc., and is used to eliminate component segregation, improve system homogeneity, and ensure stable and consistent product performance.

[0020] The term "heating" as used in this article refers to the process of using an external heat source to control the temperature and input energy into a material system, so that the material reaches a predetermined temperature and is maintained for a certain period of time, thereby reducing the viscosity of the system, promoting the melting of the material, accelerating the reaction rate, improving the dissolution or dispersion efficiency, and enhancing the interaction between components.

[0021] The term "dispersion" as used in this article refers to the process of uniformly distributing solid particles, droplets, or immiscible components in a continuous phase, eliminating agglomeration, and forming a stable dispersion system.

[0022] The term "stirring" as used in this article refers to the operation of causing materials to flow, mix, and transfer mass through mechanical external force, which is used to promote uniform mixing of components, enhance heat and mass transfer, improve dispersion, and avoid local concentration or temperature unevenness.

[0023] As used in this article, “droplet addition” refers to the addition operation of one or more liquid materials into another material system in a dropwise, slow, continuous or intermittent manner.

[0024] In a first aspect, the present invention provides: a method for preparing a highly hydrophobic mica-cinnamaldehyde composition, comprising the following steps: (1) Mix γ-aminopropyltriethoxysilane (KH550), water and mica to obtain slurry A; (2) Stir slurry A at 60-110℃ for 20-40 minutes; (3) n-Octyltriethoxysilane (OTES) and dodecyltriethoxysilane are mixed with slurry A to obtain slurry B; (4) Stir slurry B at 70-90℃ for 20-40 minutes; (5) Mix ammonia water and slurry B to obtain slurry C; (6) Stir slurry C at 125-135℃ for 1-2 hours to obtain modified mica (NM). (7) Cinnamaldehyde (CA) is mixed with modified mica (NM) to obtain a highly hydrophobic mica-cinnamaldehyde composition (NM-CA).

[0025] Preferably, the volume ratio of γ-aminopropyltriethoxysilane in step (1), n-octyltriethoxysilane in step (3) and dodecyltriethoxysilane in step (3) is 1-2:0.6-1:0.6-1, in mL:mL:mL.

[0026] Any point value or any subrange value within the range of 1-2:0.6-1:0.6-1 (unit: mL:mL:mL) is applicable to this invention, including but not limited to 2:1:1, 1:1:0.6, 2:0.6:1, 1.6:0.6:0.6, 1.4:0.7:0.7, 1.2:0.8:0.8, 1.0:0.9:0.9, and 1.0:1.0:0.8.

[0027] More preferably, the volume ratio of γ-aminopropyltriethoxysilane in step (1), n-octyltriethoxysilane in step (3) and dodecyltriethoxysilane in step (3) is 2:1:1, in mL:mL:mL.

[0028] Preferably, the ratio of the mass of mica in step (1) to the total volume of γ-aminopropyltriethoxysilane in step (1), n-octyltriethoxysilane in step (3) and dodecyltriethoxysilane in step (3) is 50 g: 1-2 mL.

[0029] Any point value or any sub-range value within the range of 50g:1-2mL is applicable to this invention, including but not limited to 50g:1mL, 50g:1.1mL, 50g:1.2mL, 50g:1.3mL, 50g:1.4mL, 50g:1.5mL, 50g:1.6mL, 50g:1.7mL, 50g:1.8mL, 50g:1.9mL, and 50g:2.0mL.

[0030] More preferably, the ratio of the mass of mica in step (1) to the total volume of γ-aminopropyltriethoxysilane in step (1), n-octyltriethoxysilane in step (3) and dodecyltriethoxysilane in step (3) is 50 g: 1-1.4 mL.

[0031] More preferably, the ratio of the mass of mica in step (1) to the total volume of γ-aminopropyltriethoxysilane in step (1), n-octyltriethoxysilane in step (3) and dodecyltriethoxysilane in step (3) is 50 g: 1.24-1.4 mL.

[0032] Preferably, the water in step (1) is selected from at least one of pure water, deionized water or distilled water.

[0033] More preferably, the water in step (1) is pure water.

[0034] Preferably, the mass of mica and the volume of water in step (1) are 50g: 0.5-1.5mL.

[0035] Any point value or any sub-range value within the range of 50g:0.5-1.5mL is applicable to this invention, including but not limited to 50g:0.5mL, 50g:0.6mL, 50g:0.7mL, 50g:0.8mL, 50g:0.9mL, 50g:1mL, 50g:1.1mL, 50g:1.2mL, 50g:1.3mL, 50g:1.4mL, and 50g:1.5mL.

[0036] More preferably, the mass of mica and the volume of water in step (1) are 50g:1mL.

[0037] Preferably, the temperature in step (2) is 70-100℃ and the time is 20-40min.

[0038] Any point value or any sub-range value within the range of 70-100℃ is applicable to this invention, including but not limited to 70℃, 71℃, 72℃, 73℃, 74℃, 75℃, 76℃, 77℃, 78℃, 79℃, 80℃, 81℃, 82℃, 83℃, 84℃, 85℃, 86℃, 87℃, 88℃, 89℃, 90℃, 91℃, 92℃, 93℃, 94℃, 95℃, 96℃, 97℃, 98℃, 99℃, and 100℃.

[0039] Any point value or any sub-range value within the range of 20-40 min is applicable to this invention, including but not limited to 20 min, 21 min, 22 min, 23 min, 24 min, 25 min, 26 min, 27 min, 28 min, 29 min, 30 min, 31 min, 32 min, 33 min, 34 min, 35 min, 36 min, 37 min, 38 min, 39 min, and 40 min.

[0040] More preferably, the temperature in step (2) is 80°C and the time is 30 min.

[0041] Preferably, the temperature in step (4) is 75-85℃ and the time is 20-40min.

[0042] Any point value or any sub-range value within the range of 75-85℃ is applicable to this invention, including but not limited to 75℃, 76℃, 77℃, 78℃, 79℃, 80℃, 81℃, 82℃, 83℃, 84℃, and 85℃.

[0043] Any point value or any sub-range value within the range of 20-40 min is applicable to this invention, including but not limited to 20 min, 21 min, 22 min, 23 min, 24 min, 25 min, 26 min, 27 min, 28 min, 29 min, 30 min, 31 min, 32 min, 33 min, 34 min, 35 min, 36 min, 37 min, 38 min, 39 min, and 40 min.

[0044] More preferably, the temperature in step (4) is 80°C and the time is 30 min.

[0045] Preferably, in step (5), the mass percentage of the ammonia water is 0.5%-1.5%, and the amount added is 2-3 mL.

[0046] Any point value or any sub-range value within the range of 0.5%-1.5% is applicable to this invention, including but not limited to 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, and 1.5%.

[0047] Any point value or any sub-range value within the range of 2-3 mL is applicable to this invention, including but not limited to 2 mL, 2.1 mL, 2.2 mL, 2.3 mL, 2.4 mL, 2.5 mL, 2.6 mL, 2.7 mL, 2.8 mL, 2.9 mL, and 3 mL.

[0048] Preferably, the volume ratio of cinnamaldehyde in step (7) to the mass ratio of mica in step (1) is 0.02-0.05 mL: 50 g.

[0049] Any point value or any sub-range value within the range of 0.02-0.05 mL:50 g is applicable to this invention, including but not limited to 0.02 mL:50 g, 0.021 mL:50 g, 0.022 mL:50 g, 0.023 mL:50 g, 0.024 mL:50 g, 0.025 mL:50 g, 0.026 mL:50 g, 0.027 mL:50 g, 0.028 mL:50 g, 0.029 mL:50 g, and 0.03 mL:50 g.

[0050] Based on further solutions to the technical problems of the present invention, or simultaneous solutions to multiple technical problems, the preferred solution in the technical solution provided in the first aspect of the present invention includes: The first preferred solution is to use three silane coupling agents—KH550, OTES, and DTES—for synergistic modification. This solution not only addresses the technical problems of insufficient hydrophobicity and poor waterproof and sweatproof effects of mica, but also further solves the technical issues of limited hydrophobic effect, large usage volume, and high cost associated with using a single silane coupling agent.

[0051] The second preferred option is to control the total amount of silane coupling agent added to 1-2 mL / 50g mica. This technical solution, while addressing the technical problem of "insufficient hydrophobic modification effect of mica," further resolves the technical issues of "excessive coupling agent dosage, high raw material costs, and unfavorable conditions for industrial production."

[0052] The third preferred option is to use a dry modification process with ammonia as the coupling reaction aid. This technical solution not only solves the problems of "low efficiency of coupling agent and mica binding and poor modification effect", but also addresses the technical issues of "complex reaction process, environmental unfriendliness, and uncontrollable operation".

[0053] The fourth preferred option is to load cinnamaldehyde onto highly hydrophobic mica to form a highly hydrophobic mica-cinnamaldehyde composition. This technical solution not only solves the technical problem of "mica having a single function and lacking UV protection capability", but also further addresses the technical problems of "small molecule sunscreens being volatile, highly irritating, and having poor stability".

[0054] Secondly, the present invention provides a highly hydrophobic mica-cinnamaldehyde composition prepared by the above preparation method.

[0055] Thirdly, the present invention provides the application of the highly hydrophobic mica-cinnamaldehyde composition prepared by the above preparation method in the preparation of cosmetics.

[0056] The present invention has at least the following beneficial effects: 1. Compared with the prior art, the present invention has better technical effects in terms of hydrophobicity, softness and skin-fitting properties, UV protection and raw material dosage.

[0057] According to experimental tests, the present invention achieves high hydrophobic properties by using a dry modification process of first pretreating with KH550 and then introducing other silane coupling agents in stages, so that the contact angle of hydrophobically modified mica reaches 150.58°.

[0058] Although existing dry modification processes can achieve a contact angle of around 153° by simultaneously adding three silane coupling agents, the total amount of silane coupling agents used is relatively high. In contrast, the total amount of silane coupling agent used in this invention is only 1.24 mL / 50 g mica, which can achieve a similar high hydrophobic effect with lower raw material consumption. This increases the contact angle from around 120° in conventional modification to 150°, while significantly reducing the amount of silane coupling agent used from the high amount used in existing single or compound modification techniques to below 1-2 mL / 50 g mica.

[0059] 2. The technical concept differences between the present invention and the prior art include, but are not limited to, the use of three silane coupling agents, KH550, OTES and DTES, for stepwise synergistic modification, dry modification process, using ammonia as a reaction aid to improve coupling efficiency, and combining highly hydrophobic mica with cinnamaldehyde to achieve sun protection function.

[0060] 3. Compared with the prior art, the present invention provides a technical solution for cosmetic fillers that combines multifunctionality, low irritation, and green environmental protection, which is more suitable for the actual application needs in the cosmetic field.

[0061] 4. Although the present invention is not significantly superior to the prior art in terms of conventional physicochemical indicators such as whiteness and particle size, it has significant positive technical effects in terms of hydrophobicity improvement, coupling agent dosage control, reaction efficiency and modification uniformity, biocompatibility, waterproof and sweatproof and UV protection functions.

[0062] Furthermore, based on the present invention: 1. Based on the comparison between Example 1 and Comparative Examples 1, 5, and 6, this invention employs a combination of techniques, including KH550 first forming a hydrolysate with pure water, stepwise addition of OTES and DTES, ammonia-catalyzed condensation, and Schiff bond-loaded cinnamaldehyde, to achieve a high contact angle and stable cinnamaldehyde loading with lower silane dosage. The powder dispersibility and water resistance are significantly improved, and the process is environmentally friendly and suitable for industrialization. The combined technical effect is superior to the sum of the effects of each individual technique.

[0063] 2. Based on the comparison of Examples 1, 2, and 3 with Comparative Example 3, the present invention purposefully selects a narrow range of mica to coupling agent volume ratios not mentioned in the prior art from the wide range of silane coupling agent ratios and dosage ranges disclosed in the prior art, and controls it at 50g:1.0-2.0mL, KH550:OTES:DTES=1-2:0.6-1:0.6-1, achieving unexpected technical effects such as higher hydrophobicity with low silane dosage.

[0064] 3. Based on the comparison of Example 1 and Comparative Example 6, this invention transfers the existing technology of stepwise hydrolysis grafting of silane coupling agents, used in the field of inorganic powder surface modification, to the fields of cosmetic sunscreens and hydrophobic carrier-loaded active ingredients. This achieves superior technical effects such as high hydrophobicity, cinnamaldehyde loading, and a contact angle far exceeding that of wet modification, overcoming technical difficulties such as silane self-polymerization caused by organic solvents, solvent residue, high drying energy consumption, and complex processes that are difficult to scale up during the transfer process.

[0065] 4. Based on the comparison of Example 1 and Comparative Example 1, this invention modifies known products with high hydrophobicity in existing technologies using mica, discovering a new property that allows it to be used as a hydrophobic carrier to load cinnamaldehyde while maintaining essentially the same hydrophobicity. This allows for new applications in cosmetics, such as sunscreen, soothing, and sustained release of active ingredients. This achieves the technical effect of synergistic high hydrophobicity and loading function, reducing the irritation of cinnamaldehyde.

[0066] 5. Based on existing technology for the hydrophobic modification of inorganic powders and cosmetic fillers, there are still technical problems to be solved, such as low dosage, high hydrophobicity, balance of active ingredient loading, environmental protection and high efficiency. However, the problems of complex process, solvent pollution and unstable effect have not been successfully solved. This invention successfully solves this technical problem.

[0067] 6. Based on the comparison of Examples 1 and 4 with Comparative Example 4, the present invention employs a low-temperature heating and stirring method (60-110°C) that has been abandoned in the art due to technical bias. This overcomes the long-standing technical bias in the art that "the higher the temperature, the more complete the silane grafting." Actual practice has proven that excessively high temperatures easily lead to silane decomposition, while medium to low temperatures are more conducive to selective grafting and amino retention, thereby obtaining better hydrophobicity and reaction selectivity. Attached Figure Description

[0068] Figure 1 The image shows the contact angle test results of the highly hydrophobic mica-cinnamaldehyde composition obtained in Example 1.

[0069] Figure 2 The image shows the contact angle test results of the highly hydrophobic mica-cinnamaldehyde composition obtained in Example 2.

[0070] Figure 3 The image shows the contact angle test results of the highly hydrophobic mica-cinnamaldehyde composition obtained in Example 3.

[0071] Figure 4 The image shows the contact angle test results of the highly hydrophobic mica-cinnamaldehyde composition obtained in Example 4.

[0072] Figure 5 The image shows the contact angle test results of the highly hydrophobic mica material obtained in Comparative Example 1.

[0073] Figure 6 The image shows the contact angle test results of the mica-cinnamaldehyde compositions obtained in Comparative Examples 2 and 3.

[0074] Figure 7 The image shows the contact angle test results of the mica-cinnamaldehyde compositions obtained in Comparative Examples 4 and 5.

[0075] Figure 8 The image shows the contact angle test results of the mica-cinnamaldehyde composition obtained in Comparative Example 6.

[0076] Figure 9a This is the infrared full-spectrum detection image of the highly hydrophobic cosmetic-grade mica material obtained by this invention.

[0077] Figure 9b The infrared spectrum (3000-2800 cm⁻¹) of the highly hydrophobic cosmetic-grade mica material obtained by this invention. -1 Magnified detection image.

[0078] Figure 9c This is the infrared full spectrum detection image of the highly hydrophobic mica-cinnamaldehyde composition obtained in this invention.

[0079] Figure 9d The infrared spectrum (1700-1500 cm⁻¹) of the highly hydrophobic mica-cinnamaldehyde composition obtained in this invention. -1 Magnified detection image.

[0080] Figure 10 This is the UV absorption test diagram of the highly hydrophobic mica-cinnamaldehyde composition obtained in this invention.

[0081] Figure 11a This is the transdermal UV absorption spectrum of pure cinnamaldehyde solution at different time points.

[0082] Figure 11b These are transdermal UV absorption spectra of the highly hydrophobic mica-cinnamaldehyde composition obtained in this invention at various time points.

[0083] Figure 11c This is a line graph showing the cumulative permeation amount of the highly hydrophobic mica-cinnamaldehyde composition and pure cinnamaldehyde solution obtained in this invention over time.

[0084] Figure 12 This is a line graph showing the cumulative permeation amount of Example 1, Comparative Example 2, Comparative Example 6, and pure cinnamaldehyde solution over time. Detailed Implementation

[0085] The following non-limiting embodiments are intended to enable those skilled in the art to gain a more comprehensive understanding of the present invention, but do not limit the invention in any way. The following content is merely an exemplary description of the scope of protection claimed by the present invention, and those skilled in the art can make various changes and modifications to the present invention based on the disclosed content, and such changes should also fall within the scope of protection claimed by the present invention.

[0086] The present invention will be further described below by way of specific embodiments. Unless otherwise specified, all instruments, devices, equipment, reagents, products, etc., used in the embodiments of the present invention are obtained through conventional commercial means.

[0087] The raw materials are shown in Table 1 below: Table 1

[0088] Example 1 A highly hydrophobic mica-cinnamaldehyde composition and its preparation method: (1) Add 0.620 mL of γ-aminopropyltriethoxysilane (KH550) to 1 mL of pure water to form a hydrolysate, and then slowly add it dropwise to 50 g of mica that is uniformly stirred. Stir to disperse it fully to obtain slurry A. (2) Heat and stir slurry A at 80°C for 0.5 h; (3) Slowly add 0.310 mL of n-octyltriethoxysilane (OTES) and 0.310 mL of dodecyltriethoxysilane (DTES) to the uniformly stirred slurry A, and stir to disperse it fully to obtain slurry B; (4) Heat and stir slurry B at 80°C for 0.5 h; (5) Slowly add 2.5 mL of ammonia water to the uniformly stirred slurry B, and stir to disperse it fully to obtain slurry C; (6) Heat and stir slurry C at 130°C for 1.5 h to obtain modified mica (NM). (7) 0.025 mL of cinnamaldehyde (CA) was slowly added dropwise to the uniformly stirred modified mica (NM). After stirring for a certain period of time, a highly hydrophobic mica-cinnamaldehyde composition (NM-CA) with sun protection was obtained.

[0089] Example 2 A highly hydrophobic mica-cinnamaldehyde composition and its preparation method: Compared with Example 1, the only difference is the change in the volume ratio of KH550, OTES, and DTES, as shown in Table 2 below: Table 2

[0090] The rest is the same as in Example 1.

[0091] Example 3 A highly hydrophobic mica-cinnamaldehyde composition and its preparation method: Compared to Example 1, the only difference is the change in the overall volume of KH550, OTES, and DTES, as shown in Table 3 below: Table 3

[0092] The rest is the same as in Example 1.

[0093] Example 4 A highly hydrophobic mica-cinnamaldehyde composition and its preparation method: Compared with Example 1, the only difference is the change in the heating temperature of step (2), as shown in Table 4 below: Table 4

[0094] The rest is the same as in Example 1.

[0095] Comparative Example 1 A highly hydrophobic mica, which is identical to Example 1 except for step (7).

[0096] Comparative Example 2 A highly hydrophobic mica-cinnamaldehyde composition, compared with Example 1, is identical except that the amount of cinnamaldehyde is changed to 0.1 mL.

[0097] Comparative Example 3 A highly hydrophobic mica-cinnamaldehyde composition, compared with Example 1, only the total volume of KH550, OTES and DTES is changed to 3.525, and the rest is the same as Example 1.

[0098] Comparative Example 4 A highly hydrophobic mica-cinnamaldehyde composition, compared with Example 1, only the temperature of step (2) is changed to 120°C, and the rest is the same as Example 1.

[0099] Comparative Example 5 A highly hydrophobic mica-cinnamaldehyde composition, compared with Example 1, only the step (1) is changed, without the addition of pure water, specifically as follows: (1) 0.620 mL of γ-aminopropyltriethoxysilane (KH550) was slowly added dropwise to 50 g of mica that was uniformly stirred. After stirring to disperse it fully, slurry A was obtained. The rest is the same as in Example 1.

[0100] Comparative Example 6 A highly hydrophobic mica-cinnamaldehyde composition and its preparation method: (1) Disperse 10g of mica in 35mL of N,N In dimethylformamide (DMF), stir to fully disperse it, and slurry A is obtained; (2) Add a total of 1.875 mL of γ Aminopropyltriethoxysilane (KH550), n-octyltriethoxysilane (OTES), and dodecyltriethoxysilane (DTES) were dissolved in slurry A in a volume ratio of 1:1:1 (mL:mL:mL). After stirring until fully dissolved, slurry B was obtained. (3) The slurry B was refluxed and heated at 120°C for 1.5 hours; (4) Add 25 mL of pure water to the slurry B from step (3) and stir to dissolve it completely to obtain slurry C; (5) The slurry C was refluxed at 120°C for 1.5 h to obtain slurry D; (6) Filter the slurry D to obtain a precipitate, wash it three times with anhydrous ethanol and pure water respectively, and dry it at 105℃ for 4 hours to obtain the precipitate.

[0101] (7) 0.025 mL of cinnamaldehyde (CA) was slowly added dropwise to the uniformly stirred slurry. After stirring for a certain period of time, a highly hydrophobic mica-cinnamaldehyde composition (NM-CA) with sun protection was obtained.

[0102] Detection Example 1 Contact angle: Weigh 0.3g of sample and compress it into a tablet using a YP-2 hydraulic tablet press. Hold the pressure at 20MPa for 5 minutes. The water droplet size is 10μL. Then, measure the contact angle using a KJ.63-JJC-1 contact angle measuring instrument. Compress the tablet three times and take the average value as the final value.

[0103] The test results are shown in Table 5 and Figures 1-8 .

[0104] Table 5

[0105] Detection Example 2 Infrared testing: A small amount of powder sample was mixed and ground with an appropriate amount of KBr powder. The sample was then prepared into a sheet-like standard sample with a diameter of 13 mm and a thickness of 1 mm using a YP-2 hydraulic tablet press. The sample was then detected using an iCAN9 Fourier transform infrared spectrometer.

[0106] The infrared detection results of Example 1 are shown below. Figure 9a , Figure 9b , Figure 9c , Figure 9d ,in Figure 9a , 9c This is the full infrared spectrum. Figure 9b , 9d This is a magnified view of a portion of the full infrared spectrum.

[0107] Depend on Figure 9a It can be seen that the obtained modified mica NM has a density of 3617 cm⁻¹. -1 905cm -1 The peak at 1008 cm⁻¹ represents the characteristic absorption peak of the stretching vibration of the hydroxyl group (-OH) in hydrophobically modified mica NM. Compared with unmodified mica M, the absorption peak intensity is enhanced, indicating an increase in the hydroxyl content on the surface of the modified mica. This may be due to the combination of residual water in the system with the hydroxyl groups on the mica surface when ammonia is used as a modifying agent, and the superposition of silanol groups generated by silane hydrolysis; -1 The strong absorption peak at 826 cm⁻¹ represents the antisymmetric stretching vibration absorption peak of Si-O-Si; -1 The peak at 748 cm⁻¹ represents the symmetrical stretching vibration absorption peak of Si-O-Si. Compared with unmodified mica M, the Si-O-Si absorption peak intensity of modified mica NM is enhanced. This is because the Si-O-Si formed by the silane coupling agent grafted onto the mica surface coincides with the Si-O-Si vibrational absorption band in the mica. -1 The absorption peak at 688 cm⁻¹ represents the Al-O-Si stretching vibration absorption peak in mica; -1 The absorption peak at that location represents a weak characteristic peak generated by the bending vibration of the Si-O bonds in mica. Figure 9a Magnify, and you get Figure 9b Modified mica NM at 2929 cm⁻¹ -1 2857cm -1 The absorption peaks of the -CH3 and -CH2 stretching vibrations observed indicate that the silane coupling agent molecules were successfully grafted onto the surface of the mica powder via chemisorption. Figure 9c It can be seen that the hydrophobic mica-cinnamaldehyde composition NM-CA at 1008 cm⁻¹ -1The absorption peak of Si-O-Si is slightly weaker than that of hydrophobically modified mica NM. This may be due to the weak shielding effect of cinnamaldehyde on the mica surface after being loaded through Schiff bonds, which does not affect the hydrophobic modification result; at 905 cm⁻¹ -1 688cm -1 The absorption peaks at these locations are the background peak of the system and the weak characteristic peak generated by the out-of-plane bending vibration of the Si-O bond in mica, respectively, and are not significantly different from those of hydrophobically modified mica NM; Figure 9c Magnify, and you get Figure 9d The hydrophobic mica-cinnamaldehyde composition NM-CA at 1657 cm⁻¹ -1 The newly added C=N Schiff stretching vibration peak indicates that the aldehyde group of cinnamaldehyde underwent a condensation reaction with the amino group of KH550 grafted onto the mica surface; at 1639 cm⁻¹ -1 The peak at this point is the C=C stretching vibration peak of the cinnamaldehyde aromatic ring. It superimposed on the original vibration peak, and the peak shape was significantly enhanced, which further indicates that cinnamaldehyde was successfully loaded onto the surface of hydrophobically modified mica to form the hydrophobic mica-cinnamaldehyde composition NM-CA.

[0108] Detection Example 3 Ultraviolet absorption test: Using cyclohexane as solvent, the highly hydrophobic mica-cinnamaldehyde composition sample was eluted for 2 h and centrifuged for 15 min to collect the supernatant. With hydrophobic modified mica as a blank control, a 2-8 μg / mL cinnamaldehyde-cyclohexane standard solution was prepared and detected in the wavelength range of 200-500 nm using a UV-2600 spectrophotometer.

[0109] The UV absorption results of Example 8 are shown in [reference needed]. Figure 10 .

[0110] Depend on Figure 10 It was found that pure cinnamaldehyde solution (CA) has a characteristic absorption peak at 281 nm, while the highly hydrophobic mica-cinnamaldehyde composition (NM-CA) shows a characteristic absorption peak at 292 nm, with a red shift that better matches the actual wavelength range for UV protection. This red shift indicates that cinnamaldehyde molecules interact with the mica carrier surface, confirming the successful loading. Therefore, the successful preparation of NM-CA is verified.

[0111] Detection Example 4 Transdermal permeation test: A transdermal experiment was conducted using porcine skin. Four groups of samples were prepared using polydimethylsiloxane as the dispersion medium (Sample 1: polydimethylsiloxane only; Sample 2: cinnamaldehyde dispersed in polydimethylsiloxane; Sample 3: hydrophobically modified mica dispersed in polydimethylsiloxane; Sample 4: hydrophobically modified mica loaded with cinnamaldehyde dispersed in polydimethylsiloxane). The detached porcine keratinocytes were fixed in a diffusion cell with the supply chamber facing the diffusion chamber. PBS-anhydrous ethanol (7:3) receiving solution was added to the receiving chamber. After applying 0.8 g of sample to each group, samples were taken and replenished at 1 h, 2 h, 4 h, 8 h, 12 h, and 24 h. A standard curve was established using ultraviolet spectrophotometry with 0.1–10.0 μg / mL cinnamaldehyde standard solutions. The absorbance values ​​of the samples at each time point were measured, the cumulative transdermal permeation was calculated, and the transdermal curve was plotted to verify the sample permeation behavior and eliminate interference.

[0112] The transdermal penetration test results of Example 1 are as follows: Figure 11a , Figure 11b , Figure 11c . Figure 11a , Figure 11b To collect pure cinnamaldehyde solution and highly hydrophobic mica-cinnamaldehyde composition as transdermal feed solutions at 1h, 2h, 4h, 8h, 12h, and 24h, and to visualize the results using ultraviolet light; Figure 11c To calculate the transdermal concentration of cinnamaldehyde in pure cinnamaldehyde solution (CA) and highly hydrophobic mica-cinnamaldehyde composition (NM-CA) at different time periods using a standard curve, and then to calculate the amount of cinnamaldehyde permeated at each time period.

[0113] observe Figure 11a , Figure 11b , Figure 11c The transdermal concentration of cinnamaldehyde increased with transdermal time. Swine skin penetration experiments showed that the highly hydrophobic mica-cinnamaldehyde composition (NM-CA) retained the 200–300 nm UV absorption of pure cinnamaldehyde solution (CA) and exhibited good sustained-release capacity due to the loading effect. Pure cinnamaldehyde solution (CA) showed a skin penetration rate of approximately 17 μg / mL after 12 h, exhibiting rapid penetration characteristics and posing a significant risk of skin irritation; while the composition (NM-CA) showed a penetration rate of only approximately 2 μg / mL, significantly reducing the skin penetration rate and amount of cinnamaldehyde, effectively reducing the risk of irritation from high concentrations, and improving safety.

[0114] The transdermal penetration test results of Example 1, Comparative Example 2, and Comparative Example 6 are as follows: Figure 12 .

[0115] observe Figure 12It can be seen that the cumulative permeation of cinnamaldehyde in Example 1 is significantly lower than that in Comparative Examples 2 and 6 and pure cinnamaldehyde, and the release curve is stable with no burst release, demonstrating better sustained-release performance. In contrast, Comparative Examples 2 and 6 have faster permeation rates and poor release controllability, and their sustained-release effect is significantly inferior to that of Example 1. The experimental results fully demonstrate that the hydrophobic modification and loading process adopted in this invention can effectively delay the transdermal release of active ingredients, improve product safety and long-lasting effect, and the technical effect is superior to that of the comparative examples.

[0116] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing a highly hydrophobic mica-cinnamaldehyde composition, characterized in that, Includes the following steps: (1) Mix γ-aminopropyltriethoxysilane, water and mica to obtain slurry A; (2) Stir slurry A at 60-110℃ for 20-40 minutes; (3) n-Octyltriethoxysilane and dodecyltriethoxysilane are mixed with slurry A to obtain slurry B; (4) Stir slurry B at 70-90℃ for 20-40 minutes; (5) Mix ammonia water and slurry B to obtain slurry C; (6) Stir slurry C at 125-135℃ for 1-2 hours to obtain modified mica; (7) Cinnamaldehyde is mixed with modified mica to obtain a highly hydrophobic mica-cinnamaldehyde composition.

2. The preparation method according to claim 1, characterized in that, The volume ratio of γ-aminopropyltriethoxysilane in step (1), n-octyltriethoxysilane in step (3) and dodecyltriethoxysilane in step (3) is 1-2:0.6-1:0.6-1, in mL:mL:mL.

3. The preparation method according to claim 1, characterized in that, The ratio of the mass of mica in step (1) to the total volume of γ-aminopropyltriethoxysilane in step (1), n-octyltriethoxysilane in step (3) and dodecyltriethoxysilane in step (3) is 50 g: 1-2 mL.

4. The preparation method according to claim 3, characterized in that, The ratio of the mass of mica in step (1) to the total volume of γ-aminopropyltriethoxysilane in step (1), n-octyltriethoxysilane in step (3) and dodecyltriethoxysilane in step (3) is 50 g: 1-1.4 mL.

5. The preparation method according to claim 1, characterized in that, The mass of mica and the volume of water in step (1) are 50g: 0.5-1.5mL.

6. The preparation method according to claim 1, characterized in that, The temperature in step (2) is 70-100℃ and the time is 20-40min.

7. The preparation method according to claim 1, characterized in that, The stirring temperature in step (4) is 75-85℃ and the stirring time is 20-40 min; in step (5), the mass percentage of ammonia water is 0.5%-1.5% and the amount added is 2-3 mL.

8. The preparation method according to claim 1, characterized in that, The volume ratio of cinnamaldehyde in step (7) to the mass ratio of mica in step (1) is 0.02-0.05 mL: 50 g.

9. The highly hydrophobic mica-cinnamaldehyde composition prepared by the preparation method according to any one of claims 1-8.

10. The use of the highly hydrophobic mica-cinnamaldehyde composition prepared by the preparation method according to any one of claims 1-8 in the preparation of cosmetics.

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