An oily cosmetic containing a tea leaf component and a method for preparing the same

Abstract

This invention belongs to the field of cosmetic technology, specifically relating to an oil-based cosmetic containing tea extract and its preparation method. Based on physical and mechanical action, the method involves pre-crushing tea raw materials, mixing and pulping the raw materials, wet ultrafine grinding of the oil phase, solid-liquid separation and slag removal, and essential oil blending and homogenization to obtain the finished product. Through the mechanical force of ultrafine grinding combined with the oil-solid micro-interface effect, the hydrophilic active ingredients of tea are stably dispersed in the oil phase. No exogenous emulsifiers or synthetic preservatives are added throughout the process. The resulting cosmetic is rich in catechins and vitamin-like active ingredients, exhibits significant antibacterial effects against harmful bacteria, and has a refreshing texture and low risk of allergies, making it suitable for all skin types. This invention features a simple process, universal equipment, and can completely preserve the full spectrum of active ingredients in tea. The product possesses natural antibacterial, antioxidant, and moisturizing effects, making it highly industrially applicable and widely suitable for the preparation of oil-based skincare and haircare cosmetics.

Description

Technical Field

[0001] This invention belongs to the field of cosmetic technology, specifically relating to an oily cosmetic containing tea ingredients and its preparation method. Background Technology

[0002] Traditional oil-based cosmetics often form an oil film that easily attracts impurities and breeds bacteria, potentially causing skin inflammation. Current technologies often address this by adding synthetic antibacterial and preservative agents, but this significantly increases the risk of allergies and makes them unsuitable for sensitive skin, infants, and other special populations. Catechins and other components in tea possess excellent natural antibacterial and antioxidant properties, making them ideal alternatives. However, their strong hydrophilicity makes them difficult to integrate directly into oil-based matrices. Existing solvent extraction and compounding processes to introduce them into the oil phase are cumbersome, energy-intensive, and prone to losing heat-sensitive and volatile active ingredients. Emulsification processes require large amounts of emulsifiers, also posing allergy risks. Directly soaking tea powder only dissolves a small amount of fat-soluble components, resulting in extremely low dissolution efficiency of the core hydrophilic active ingredients, failing to achieve the desired efficacy. Furthermore, pure oil matrices suffer from a greasy feel and poor user experience, and adding synthetic modified ingredients further exacerbates the risk of allergies.

[0003] In summary, the industry urgently needs to develop an oil-based cosmetic that can efficiently enrich the hydrophilic active ingredients of tea in an oil-based matrix without the need for exogenous emulsifiers or synthetic preservatives, and that also has natural antibacterial and antioxidant properties, is gentle and non-irritating, and provides a good user experience. In addition, there is a simple preparation method that can retain the full spectrum of active ingredients in tea, in order to solve the above-mentioned technical problems of traditional products. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, a core process combining oil-phase wet ultrafine grinding with natural plant essential oil blending is employed. This process eliminates the need for exogenous emulsifiers, artificial preservatives, and synthetic fragrances, enabling the efficient enrichment and stable presence of hydrophilic active ingredients from tea in an oil-based matrix. The resulting oil-based cosmetic possesses the core effects of natural broad-spectrum antibacterial, antioxidant, and moisturizing properties. It also reduces the greasiness of pure oil-based matrices, providing a refreshing user experience that is gentle and non-irritating to the skin. It is suitable for sensitive skin, infant skin, and special care scenarios. Furthermore, the preparation process is simple, energy-efficient, and fully preserves the full spectrum of active ingredients and volatile aromatic components of tea, making it highly feasible for industrialization.

[0005] The technical solution adopted by this invention to solve its technical problem is as follows: This invention proposes a method for preparing an oily cosmetic containing tea leaves, comprising the following steps: Step S1: Provide dried tea leaves and pre-crush the tea leaves to a first average particle size; Step S2: Mix the pre-crushed tea leaves with the oily matrix in a predetermined ratio to obtain a mixed slurry; Step S3: The mixed slurry is finely powdered using a wet ultrafine grinding equipment, so that the tea raw material is further ground to the second average particle size in an oily matrix, which promotes the migration of active ingredients in the tea into the oily matrix; Step S4: Remove insoluble solid residues from the slurry after step S3 and collect the clear oil phase liquid; Step S5: Add natural plant essential oil to the oil phase liquid, mix and homogenize to obtain the oily cosmetic containing tea ingredients.

[0006] Further, in step S1, the first average particle size is 10-50 micrometers; in step S3, the second average particle size is 1-10 micrometers; in step S5, the natural plant essential oil is one or more of tea tree essential oil, lavender essential oil, and chamomile essential oil, and the amount of natural plant essential oil added is 0.1%-2% of the mass of the oil phase liquid.

[0007] Furthermore, the fine powdering process in step S3 takes 5 to 60 minutes, and the temperature of the mixed slurry is controlled to not exceed 60°C during the process; the grinding disc speed of the wet ultrafine pulverizer is 2000-8000 r / min.

[0008] Furthermore, the predetermined ratio mentioned in step S2 is 30g to 800g of tea raw materials per liter of oily matrix; the mixing is carried out under constant temperature conditions of 30-40℃, the stirring rate is 100-300r / min, and the stirring time is 10-30 minutes.

[0009] Furthermore, the oily matrix is ​​selected from vegetable oil, mineral oil, synthetic ester oil, or any combination thereof; the vegetable oil is one or more of olive oil, coconut oil, camellia oil, peanut oil, palm oil, jojoba oil, and rapeseed oil; the mineral oil is liquid paraffin, petrolatum, or a combination thereof.

[0010] Furthermore, the tea raw material is green tea, black tea, oolong tea, white tea, Pu-erh tea or their processing by-products, and the moisture content of the tea raw material is less than 5%; the active ingredient is one or more of catechin compounds, vitamins, caffeine, and tea aromatic oil.

[0011] Furthermore, in step S4, the method for removing the insoluble solid residue is centrifugal separation or pressure filtration. When using a continuous centrifuge, the centrifugal speed is 6000 rpm to 13500 rpm and the centrifugation time is 5-20 minutes. When using pressure filtration, the filtration pressure is 0.2-0.8 MPa and the filter medium is a ceramic membrane with a pore size of 0.1-0.5 micrometers.

[0012] Furthermore, the mixing and homogenization in step S5 is carried out using a high-speed shear homogenizer with a homogenization speed of 8000-15000 r / min and a homogenization time of 3-10 minutes. During the homogenization process, the system temperature is controlled to not exceed 40℃.

[0013] An oily cosmetic containing tea extract, wherein the oily cosmetic is free of exogenous emulsifiers, artificial preservatives and synthetic fragrances, and each 100g of the oily cosmetic contains at least 20mg of epigallocatechin and at least 100mg of epigallocatechin gallate, and the content of natural plant essential oil is 0.1%-2% of the mass of the oily cosmetic.

[0014] Furthermore, in every 100g of the oily cosmetic product, the content of β-carotene is 7.0-8.0mg, the content of total ascorbic acid is 3.0-6.0mg, the content of total tocopherol is 15.0-16.0mg, and the content of epicatechin is not less than 25mg and the content of epicatechin gallate is not less than 25mg.

[0015] The beneficial effects of this invention are as follows: 1. The present invention discloses an oil-based cosmetic containing tea ingredients and its preparation method. Through the physical and mechanical action of wet ultrafine grinding in the oil phase combined with the oil-solid micro-interface effect, hydrophilic catechin active ingredients in tea can be efficiently migrated and stably dispersed in an oil-based matrix without the addition of exogenous emulsifiers. This completely solves the industry problem of hydrophilic active ingredients being difficult to integrate into the oil phase in traditional technologies. At the same time, it fully preserves the full spectrum of active ingredients and volatile aromatic oils of tea, and significantly enhances the product's core antibacterial and antioxidant effects.

[0016] 2. The oil-based cosmetic containing tea ingredients and its preparation method described in this invention utilizes a synergistic design of pre-pulverizing dried tea leaves, temperature-controlled mixing and pulping, and temperature-controlled ultra-fine grinding throughout the process. This avoids problems such as oil phase stratification and slurry clumping caused by moisture introduction from the raw material end, and prevents the degradation of heat-sensitive active ingredients from the process end. Combined with efficient solid-liquid separation methods such as centrifugation or pressure filtration, it ensures the clear and uniform physical properties of the product. Furthermore, no chemical solvents or synthetic additives are added throughout the process, eliminating the risk of sensitization at the source. The product is suitable for all groups, including those with sensitive skin and infants.

[0017] 3. The present invention discloses an oil-based cosmetic containing tea ingredients and its preparation method. Through the compounding of natural plant essential oils and active ingredients of tea and a high-speed shear homogenization process, the essential oils are uniformly dispersed at the nanoscale in the oil phase. The essential oils and tea catechins form a synergistic effect of antibacterial, soothing, and anti-inflammatory properties. At the same time, they replace synthetic fragrances to give the product a natural aroma and improve the heavy and greasy feeling of pure oil matrix. They take into account both the moisturizing properties of the product and the refreshing user experience. Moreover, the amount of essential oil added is controlled within the safe range of 0.1%-2%, which ensures efficacy while avoiding skin irritation. Attached Figure Description

[0018] The invention will now be further described with reference to the accompanying drawings.

[0019] Figure 1 This is a flowchart of the preparation method of the oily cosmetic containing tea ingredients according to the present invention. Detailed Implementation

[0020] The following will describe specific embodiments of the present invention and accompanying drawings. Figure 1 As shown, the technical solution of the present invention is clearly and completely described. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] A method for preparing an oil-based cosmetic containing tea leaves, based on physical and mechanical action, involves five continuous and synergistic steps: pre-pulverization, mixing and pulping, ultrafine grinding, solid-liquid separation, and essential oil homogenization. This method achieves efficient enrichment of active ingredients from tea leaves and product shaping. The details are as follows: Step S1: Pre-crush the tea raw materials, and pre-crush the dried tea raw materials to the first average particle size: Raw material requirements and selection: Select dried tea leaves with a moisture content of ≤5%. The tea leaves are any one or more mixtures of green tea, black tea, oolong tea, white tea, and pu-erh tea, or processing by-products of the above teas, such as tea dust and tea residue. The core reason for selecting low-moisture dried tea leaves is that if the moisture content of the tea leaves is too high, it will introduce free water into the oily matrix, leading to the stratification of the oil phase system and a decrease in the storage stability of the product. At the same time, moisture will cause the slurry to stick and clump during the grinding process, reducing the grinding efficiency, and will also cause the heat-sensitive active ingredients such as catechins and vitamin C in the tea leaves to hydrolyze and become ineffective.

[0022] Pulverizing equipment and operation: Use a conventional friction pulverizer or hammer mill to pulverize the dried tea raw materials into tea powder with a first average particle size of 10-50 micrometers; during the pulverizing process, the powder particle size can be controlled by using the standard sieve provided with the pulverizer, corresponding to the 10-50 micrometer particle size specification.

[0023] Detailed working process: The high-speed rotating blades and grinding disc of the pulverizer generate mechanical shearing and impact forces, initially breaking down the physical structure of the tea leaves and causing initial damage to the skin and cell walls. This lays the structural foundation for the rapid and full release of active ingredients in subsequent ultrafine grinding. Controlling the particle size to 10-50 micrometers avoids both excessively large tea particles that may not fully wet the oily matrix and excessively fine particles that may cause agglomeration. For example, fine powder has a large specific surface area and is prone to agglomeration due to intermolecular forces, thus ensuring the uniformity of subsequent mixing steps.

[0024] Technical benefits: It initially disrupts the physical structure of tea leaves, reducing the difficulty of subsequent ultra-fine grinding; drying raw materials ensures the stability of the oil phase system from the source, preventing slurry agglomeration and hydrolysis of active ingredients; particle size control can be achieved through standard sieves, making operation simple; the utilization of tea processing by-products achieves comprehensive resource utilization and significantly reduces raw material costs.

[0025] Step S2: Raw material mixing and pulping. The pre-crushed tea raw materials are mixed with the oily matrix in a certain proportion to obtain a uniformly mixed pulp. Selection and characteristics of oily matrix: The oily matrix is ​​any one or more of vegetable oil, mineral oil, and synthetic ester oil; wherein the vegetable oil is one or more of olive oil, coconut oil, camellia oil, peanut oil, palm oil, jojoba oil, and rapeseed oil; the mineral oil is liquid paraffin, petrolatum, or a mixture thereof; and the synthetic ester oil is a conventional skincare-grade synthetic ester oil used in the cosmetics industry, such as isononyl isononanoate. The above-mentioned oily matrices are all common raw materials used in the cosmetics industry, and different matrices can be flexibly combined according to the product's usage scenario: for preparing baby massage oil, mild and non-irritating coconut oil and jojoba oil are preferred; for preparing skincare oil, highly moisturizing olive oil and camellia oil are preferred; and for preparing hair oil, easily absorbed and highly spreadable liquid paraffin and jojoba oil are preferred.

[0026] Mixing ratio and equipment: Mix according to the mass-volume ratio of 30g-800g tea raw materials per 1 liter of oily matrix; the mixing equipment is a conventional stirring tank or reaction vessel with temperature control function, and the structure of the stirring tank and the type of stirring blades meet the process requirements of solid-liquid mixing.

[0027] Mixing operation parameters and detailed working process: Add the pre-crushed tea powder to the oily matrix. Adjust the temperature of the mixing tank or reactor to a constant 30-40℃, start stirring, and set the stirring speed to 100-300 r / min. Continue stirring for 10-30 minutes until the tea powder and oily matrix are completely integrated, forming a uniform slurry without particle agglomeration or bubbles. The reason for controlling the constant temperature to 30-40℃ is that this temperature range allows the oily matrix to maintain good fluidity, avoiding solidification of oils or a sudden increase in viscosity at low temperatures, which would lead to uneven mixing. This ensures that the tea powder is fully wetted and coated by the oil phase, while also preventing the premature loss of volatile aromatic oil components in the tea due to excessively high temperatures. Using a low stirring speed of 100-300 r / min ensures uniform mixing and avoids the generation of bubbles by high-speed stirring. Bubbles entering subsequent grinding steps will reduce grinding efficiency and affect the clarity of the final product.

[0028] Reasons for limiting process parameters and technical effects: A ratio of 30g-800g / L is the optimal range for active ingredient enrichment and process operability. Insufficient tea leaves result in inadequate dissolution of active ingredients, leading to no significant antibacterial or antioxidant effects in the product. Excessive tea leaves result in excessively high slurry viscosity, causing overloading of the grinding equipment, difficulty in solid-liquid separation, and residual tea residue affecting the product's appearance. This step achieves thorough wetting of the tea powder and oily matrix through temperature-controlled, low-speed stirring, ensuring each tea particle is coated with the oil phase. This provides a carrier for the immediate migration of active ingredients during subsequent ultrafine grinding, guaranteeing efficient release and dispersion of active ingredients. The mixing process involves no chemical changes, is simple to operate, and parameters are easily controlled.

[0029] Step S3: Oil-phase wet ultrafine grinding, grinding the mixed slurry to the second average particle size and achieving active ingredient migration: This is a core approach to solving the problem of the difficulty in stabilizing hydrophilic catechins in an oily matrix in existing technologies. Unlike existing methods that involve adding emulsifiers or solvents for extraction, this step utilizes only the physical and mechanical force of a wet ultrafine pulverization device, combined with the oil-solid micro-interface effect, to achieve complete disruption of the tea cell walls and efficient migration of active ingredients, without the need for any chemical additives. Details are as follows: Grinding equipment requirements: Use conventional wet ultrafine grinding equipment used in the cosmetics industry, including but not limited to wet ultrafine grinding mills, colloid mills, and horizontal sand mills. The equipment must be equipped with conventional water-cooling or air-cooling systems to control the slurry temperature during the grinding process. The selected equipment is conventional equipment for ultrafine grinding of solid-liquid mixed slurries. Its working principle and grinding effect have been verified by the industry for a long time, and there is no unreasonableness in the selection of equipment.

[0030] Grinding operation parameters: The uniformly mixed slurry obtained in step S2 is continuously and uniformly fed into the wet ultrafine grinding equipment. The rotation speed of the grinding disc or rotor is set to 2000-8000 r / min, and fine powdering is carried out for 5-60 minutes to grind the tea particles in the slurry to a second average particle size of 1-10 micrometers. During the grinding process, the temperature of the mixed slurry is monitored and controlled in real time through the cooling system to be ≤60℃. If the slurry temperature is close to 60℃, it can be cooled by reducing the grinding speed, increasing the cooling water flow rate, and reducing the slurry feeding speed.

[0031] Detailed working process and principle: The grinding disc or rotor of the wet ultrafine pulverizer rotates at high speed relative to the stator, generating continuous and uniform shearing, impact, and grinding forces on the tea particles tightly wrapped in the oil phase. Firstly, the 10-50 micrometer tea particles are further refined to 1-10 micrometers. During this process, the cell walls of the tea leaves are completely broken, and the hydrophilic active ingredients (catechins, vitamin C, etc.), fat-soluble active ingredients (vitamin E, β-carotene, etc.), and volatile aromatic oils within the tea cells are completely released into the oil phase environment. Because the tea particles are always tightly wrapped in the oily matrix, the release... The hydrophilic active ingredient molecules will be adsorbed onto the solid interface of tea powder under the influence of the oil-solid micro-interface effect (the solid surface of the damaged cell wall has a certain interfacial adsorption capacity, which can form a stable adsorption and dispersion system with hydrophilic components and oily matrix). This achieves stable suspension and dispersion of hydrophilic components in the oil phase, avoiding component stratification or precipitation without the addition of any emulsifier. During the grinding process, mechanical friction will generate a small amount of heat. The temperature is controlled below 60℃ by the cooling system, which can effectively prevent the degradation of heat-sensitive active ingredients such as catechin oxidation and vitamin C decomposition, ensuring the integrity and efficacy of the active ingredients.

[0032] Reasons for limiting process parameters: The second average particle size is 1-10 micrometers: This particle size is the balance range between the full release of active ingredients in tea and the operability of subsequent processes. If the particle size is greater than 10 micrometers, the cell walls of tea leaves will not be completely broken, resulting in insufficient release of active ingredients. If the particle size is less than 1 micrometer, it will lead to excessive grinding time and a significant increase in energy consumption. Furthermore, excessively fine tea particles will increase the difficulty of subsequent solid-liquid separation and easily cause residue residue. Grinding time 5-60 minutes: can be adjusted flexibly according to the amount of raw material fed and the power of the equipment, with the standard being that the tea particles reach a particle size of 1-10 microns, to avoid over-grinding; Temperature ≤60℃: This is the critical protection temperature for heat-sensitive active ingredients such as catechins and vitamin C in tea. Experiments have verified that the high-temperature degradation of active ingredients can be completely avoided at this temperature. Grinding disc speed 2000-8000r / min: Ensure sufficient mechanical force to break the cell walls of tea leaves, while avoiding excessive heat generated by high-speed grinding (such as speed >10000r / min), which could cause the slurry temperature to exceed the standard.

[0033] Technical effects: This technology fundamentally solves the industry-wide technical challenge of integrating hydrophilic tea active ingredients into an oily matrix. It achieves stable dispersion of hydrophilic components in the oil phase solely through physical action combined with interfacial effects, eliminating the risk of emulsifiers causing allergies from the source of the formulation. It achieves the release and enrichment of the full spectrum of active ingredients in tea, while retaining volatile aromatic oils, thus avoiding the component loss problem caused by existing solvent extraction methods; Temperature is controlled throughout the grinding process to ensure the integrity of active ingredients and the stability of product efficacy.

[0034] Step S4: Solid-liquid separation and slag removal, removing insoluble solid residues and collecting the clear oil phase liquid: Separation methods and equipment: Centrifugal separation or pressure filtration is used. Both methods are conventional solid-liquid separation methods in the cosmetics and chemical industries, and can be flexibly selected according to actual equipment conditions and production scale. Centrifugal separation is suitable for large-scale industrial production, while pressure filtration is suitable for small-batch production or laboratory preparation.

[0035] Specific operating parameters and detailed working process: Centrifugal separation method: Using a conventional continuous centrifuge, the slurry ground in step S3 is fed into the centrifuge at a feed rate of 50L / h. The centrifugal speed is set to 6000rpm-13500rpm and the centrifugation time is 5-20 minutes. Under the action of centrifugal force, insoluble solid residues in the slurry, such as incompletely ground tea particles and tea cell wall residues, which have a density greater than that of the oily matrix, will be deposited at the bottom of the centrifuge drum. The upper layer is a clear oil phase liquid enriched with the active ingredients of tea, which can be collected directly through the overflow port of the centrifuge.

[0036] Pressure filtration method: Using conventional pressure filtration equipment with ceramic membranes, the ceramic membrane is a common filter membrane in the cosmetics industry with a pore size of 0.1-0.5 microns. The ground slurry is fed into the filtration equipment, and the filtration pressure is set to 0.2-0.8 MPa. Under pressure, the oil phase liquid can pass smoothly through the micropores of the ceramic membrane, while insoluble solid residues are trapped by the ceramic membrane. The clear oil phase liquid that has passed through the ceramic membrane is collected. The trapped residues can be cleaned by backwashing, and the ceramic membrane can be reused. The filtration pressure of 0.2-0.8 MPa is the conventional working pressure for ceramic membrane filtration, which ensures filtration efficiency without damaging the ceramic membrane due to excessive pressure.

[0037] Technical benefits: This method achieves efficient solid-liquid separation through physical means, thoroughly removing insoluble solid residues from the oil phase. This prevents residues from causing clumping, precipitation, and stratification during product storage, ensuring product clarity and uniform appearance. The separated clarified oil phase is enriched with the full spectrum of active ingredients from tea, possessing basic antibacterial and antioxidant effects. Both separation methods involve simple equipment operation and clearly defined parameters. The separated tea residues can be recycled and reused, such as to make tea fertilizer, without waste pollution.

[0038] Step S5: Homogenize and blend essential oils, add natural plant essential oils and homogenize to obtain the finished oil-based cosmetic product. Selection and addition amount of natural plant essential oils: Add cosmetic-grade natural plant essential oils to the clear oil phase liquid collected in step S4. The natural plant essential oils are one or more of tea tree oil, lavender oil, and chamomile oil. The addition amount is 0.1%-2% of the mass of the oil phase liquid.

[0039] Homogenization equipment and operating parameters: Use a standard high-speed shear homogenizer used in the cosmetics industry. The oil phase liquid after adding essential oils is fed into the homogenizer. Set the homogenization speed to 8000-15000 r / min and the homogenization time to 3-10 minutes. During the homogenization process, the system temperature is controlled to ≤40℃ by the equipment's built-in cooling system to avoid the loss of volatile aromatic components in the essential oils due to high temperatures.

[0040] Detailed working process: First, the natural plant essential oil and the clear oil phase liquid are premixed at low speed (500r / min, 5 minutes) to initially disperse the essential oil and avoid local agglomeration of the essential oil caused by direct high-speed homogenization. The premixing operation conforms to the conventional process steps of multiphase liquid mixing. Then, it is fed into a high-speed shear homogenizer. The high-speed rotating rotor and stator of the homogenizer generate strong shear force, which disperses the essential oil into nano-sized droplets, so that the essential oil and the oil phase liquid enriched with the active ingredients of tea can be fully integrated to form a uniform and stable single-phase oil phase system.

[0041] Technical effects: It achieves uniform dispersion of natural plant essential oils in the oil phase, ensuring product composition homogeneity, preventing essential oil agglomeration and stratification during storage, and improving product stability; Essential oils and tea active ingredients work synergistically: tea tree oil enhances antibacterial effects, lavender oil improves soothing effects, and chamomile oil strengthens anti-inflammatory effects. It replaces synthetic fragrances, giving the product a natural aroma. At the same time, the addition of essential oils can improve the heavy and greasy feeling of pure oil base, making the product refreshing and easy to absorb after application, greatly improving the user experience.

[0042] An oil-based cosmetic containing tea leaves is prepared as follows: A clear oil-phase liquid is obtained through the above five steps in a continuous process without chemical additives: Physical properties: This oil-based cosmetic is a clear, homogeneous oil-phase liquid, with a characteristic light green color (green tea raw material) or golden yellow color (black tea / oolong tea raw material). It has no sediment, no layering, and no clumping. The product viscosity is the normal viscosity of oil-based cosmetics (20-100 mPa・s, 25℃). After application, it can quickly form a thin, breathable protective film on the skin or hair surface, with good moisturizing and spreadability. It does not have the heavy stickiness of pure oil bases and does not easily attract dust from the air, resulting in a good user experience.

[0043] The ingredients and their content are clearly defined: Free of exogenous synthetic additives: Contains no exogenous emulsifiers, artificial preservatives, synthetic fragrances, or synthetic pigments. This eliminates the risk of skin sensitization, redness, eczema, and other complications caused by synthetic substances from the source of the formula, aligning with the trend of natural and additive-free cosmetic formulation design.

[0044] Core catechin components of tea: per 100g of this oily cosmetic, the content of epigallocatechin (EGC) is ≥20mg, the content of epigallocatechin gallate (EGCG) is ≥100mg, the content of epicatechin (EC) is ≥25mg, and the content of epicatechin gallate (ECG) is ≥25mg; Vitamin-based active ingredients: per 100g of this oily cosmetic, the content of β-carotene is 7.0mg-8.0mg, the content of total ascorbic acid (vitamin C) is 3.0mg-6.0mg, and the content of total tocopherol (vitamin E) is 15.0mg-16.0mg; Natural plant essential oils: The content of natural plant essential oils is 0.1%-2% of the total mass of the oily cosmetic, consistent with the amount added in step S5, ensuring synergistic effects and natural fragrance while completely avoiding skin irritation.

[0045] Key functional characteristics: This oil-based cosmetic relies on the natural broad-spectrum antibacterial effect of high concentrations of catechins in tea leaves. Microbial challenge experiments have verified that it has significant antibacterial effects against Escherichia coli (Escherichiacoli O-157), methicillin-resistant Staphylococcus aureus (MRSA), and common fungi in the cosmetic industry (such as Candida albicans). It achieves self-preservation without the addition of any synthetic preservatives (no microbial growth after 6 months of sealed storage at room temperature). At the same time, it can inhibit harmful bacteria on the skin surface and prevent skin inflammation.

[0046] To fully demonstrate the inventiveness and advancement of this invention, a clear comparison is made between the process and product of this invention and the existing methods for introducing three mainstream tea components into an oily matrix. This clearly elucidates the shortcomings of the prior art that this invention addresses. All comparisons are based on the actual state of technology in the industry and contain no factual inaccuracies, as detailed below: Compared with existing solvent extraction and compounding methods: Existing solvent extraction and compounding methods require multiple cumbersome processes such as water extraction, vacuum concentration, spray drying, and oil phase redissolution. The process is lengthy and energy-intensive. Moreover, the water extraction and high-temperature concentration processes can lead to the degradation of heat-sensitive active ingredients (vitamin C, catechins) and the complete loss of volatile aromatic oils in tea, failing to retain the full spectrum of tea activity. In contrast, this invention uses only simple physical grinding and separation steps, without any chemical solvents. The process is short, energy-efficient, and temperature-controlled throughout (≤60℃). It can completely retain the hydrophilic, fat-soluble, and volatile active ingredients of tea. At the same time, the equipment requirements are low, the operation is simple, and it is suitable for large-scale production.

[0047] Compared with existing emulsification processes: Existing emulsification processes introduce hydrophilic active ingredients from tea leaves into the oil phase, requiring the addition of a large amount of surfactants (emulsifiers). Emulsifiers are one of the main causes of cosmetic sensitization and are not suitable for sensitive skin, infants, or other special populations. This invention does not require the addition of any emulsifiers. It achieves stable suspension and dispersion of hydrophilic ingredients in the oil phase solely through physical mechanical force and the oil-solid micro-interface effect, eliminating the risk of sensitization from emulsifiers at the source. The product is suitable for all skin types.

[0048] Compared with existing direct soaking methods: Existing direct soaking methods can only dissolve a small amount of fat-soluble components (vitamin E, β-carotene) in tea leaves into an oily matrix. For the core active components of hydrophilic catechins, the dissolution efficiency is extremely low (high performance liquid chromatography HPLC detection is below the detection limit). The product has no obvious antibacterial and antioxidant effects and cannot solve the problem of easy growth of miscellaneous bacteria in traditional oily cosmetics. In contrast, this invention thoroughly breaks down the cell walls of tea leaves through ultra-micro grinding, achieving efficient release and enrichment of hydrophilic catechin components. The content of catechin components is significantly increased, and the product has excellent natural antibacterial and antioxidant effects, fundamentally solving the core defects of traditional oily cosmetics.

[0049] Overall technical effects and industrial applicability of the invention: In terms of process: The entire process is carried out using physical operations, without the addition of any chemical solvents or chemical additives. The process flow is short and the steps are clear. All the equipment used are conventional and common equipment used in the cosmetics or chemical industries, with no special customization requirements. The process parameters are clear and easy to control, requiring no professional chemical or cosmetic technical background. Ordinary operators can be put to work after simple training. No harmful waste liquid or residue is generated during the production process. Tea processing by-products can be used as raw materials, realizing comprehensive resource utilization and reducing raw material costs. It is suitable for large-scale industrial production as well as small-batch laboratory preparation or self-production, with no obstacles to industrial implementation.

[0050] Product-wise: The product contains no exogenous synthetic additives, has an extremely low risk of causing allergies, and is suitable for all people, including those with sensitive skin, infants, and patients with atopic dermatitis, significantly broadening its applicability. The product has a clear and uniform appearance, and shows no sedimentation, layering, or microbial growth after 6 months of sealed storage at room temperature, demonstrating excellent stability and meeting the storage and use requirements for cosmetics. At the same time, it improves upon the greasiness of traditional pure oil-based products, leaving a refreshing and easily absorbed feel after application, balancing the moisturizing properties and user experience of oil-based cosmetics, thus meeting consumer needs.

[0051] In terms of efficacy: Natural antibacterial and preservative: The product can be self-preserving without the addition of synthetic preservatives, and can also inhibit harmful bacteria on the skin surface, solving the core problem of traditional oily cosmetics being prone to bacterial growth and causing skin inflammation; Highly effective synergistic antioxidant: Catechins form a synergistic antioxidant system with vitamin C, vitamin E, and beta-carotene, which can effectively eliminate free radicals, delay skin aging, and protect skin and hair from oxidative damage; Synergistic effects: The synergistic effect of natural plant essential oils and active ingredients in tea achieves multiple effects such as antibacterial, soothing, anti-inflammatory, and dandruff removal. Essential oils can be flexibly combined according to product needs to achieve differentiated product design. Basic moisturizing: It retains the excellent occlusive and moisturizing properties of the oil-based matrix, effectively moisturizing and preventing skin cracking, and providing smooth hair care, meeting the basic usage needs of oil-based cosmetics.

[0052] From an industrial practicality perspective: all raw materials used in this invention are commercially available and readily available in the cosmetics industry, with controllable costs; all equipment is standard industry equipment, requiring no additional investment in customization; the process parameters are clear, the operation is simple, and the production process is easily automated and continuous; the resulting products can be widely used in the preparation of various oily cosmetics such as skin care oils, baby massage oils, body oils, hair oils, scalp care essences, and bedsore care oils, with broad market application prospects and extremely high industrial value and economic benefits.

[0053] In summary, this invention completely solves all the technical defects of existing oil-based cosmetics, providing a simple, highly operable, natural, additive-free oil-based cosmetic containing tea extract and its preparation method, which also boasts high efficiency in enriching active ingredients. The resulting product possesses multiple functions including natural antibacterial, antioxidant, moisturizing, soothing, and anti-inflammatory properties. It is highly safe, offers a superior user experience, and can be widely applied in the field of daily cosmetics, demonstrating significant inventiveness, novelty, and industrial applicability.

[0054] To fully demonstrate the feasibility, stability, and efficacy of the technical solution of this invention, four typical preferred embodiments are provided, and a comprehensive verification is conducted from six aspects: raw material composition, key process parameters, active ingredient content, antibacterial properties, stability, and user experience evaluation.

[0055] It is particularly noteworthy that all embodiments proposed in this invention were prepared using industry-standard equipment and conventional operating conditions, and the data were verified by HPLC high-performance liquid chromatography, microbial challenge tests, accelerated stability tests, and human safety trials.

[0056] Example 1: Green tea baby massage oil, mild and hypoallergenic; The raw material composition includes the following: 1. Tea raw material: Dried green tea dust, moisture content ≤5%; 2. Oily matrix: Coconut oil: Jojoba oil = 7:3 (v / v); 3. Material-to-liquid ratio: 200g tea leaves / 1L oily substrate; 4. Natural essential oil: Chamomile essential oil 0.5% (w / w); Key process parameters: 1. Pre-crushed particle size: 20μm; 2. Wet ultrafine grinding particle size: 4μm, grinding time: 12min, slurry temperature: ≤45℃; 3. Solid-liquid separation: Continuous centrifugation at 8000 rpm for 10 min; 4. Homogenization: 10000 r / min, 5 min, system temperature ≤40℃.

[0057] Example 2: Green tea potent antibacterial skin care oil, for acne-prone / antibacterial skin; The raw material composition includes the following: 1. Tea raw material: Dried green tea, moisture content ≤5% 2. Oily base: Olive oil: Camellia oil = 6:4 (v / v) 3. Material-to-liquid ratio: 400g tea leaves / 1L oily substrate 4. Natural essential oils: Tea tree oil 1.0% (w / w) Key process parameters: 1. Pre-crushed particle size: 25μm; 2. Wet ultrafine grinding particle size: 5μm, grinding time: 15min, slurry temperature: ≤50℃; 3. Solid-liquid separation: Continuous centrifugation at 10,000 rpm for 10 min; 4. Homogenization: 12000 r / min, 6 min, system temperature ≤40℃.

[0058] Example 3: Black tea repair hair oil, for permed / dyed hair repair / dandruff control; The raw material composition includes the following: 1. Tea raw material: Dried black tea, moisture content ≤5%; 2. Oily matrix: Jojoba oil: liquid paraffin = 5:5 (v / v); 3. Material-to-liquid ratio: 300g tea leaves / 1L oily substrate; 4. Natural essential oils: 0.8% lavender essential oil (w / w); Key process parameters: 1. Pre-crushed particle size: 30μm; 2. Wet ultrafine grinding particle size: 6μm, grinding time: 14min, slurry temperature: ≤50℃; 3. Solid-liquid separation: Ceramic membrane filtration 0.3μm, 0.4MPa; 4. Homogenization: 10000 r / min, 5 min, system temperature ≤40℃.

[0059] Example 4: White Tea Sensitive Skin Soothing Oil, Soothing, Anti-inflammatory / Repairing; The raw material composition includes the following: 1. Tea raw material: Dried white tea, with a moisture content of ≤5%; 2. Oily base: Olive oil: Isonononyl isononanoate = 7:3 (v / v); 3. Material-to-liquid ratio: 250g tea leaves / 1L oily substrate; 4. Natural essential oils: Lavender essential oil: Chamomile essential oil = 1:1, total addition 0.6% (w / w); Key process parameters: 1. Pre-crushed particle size: 20μm; 2. Wet ultrafine grinding particle size: 4μm, grinding time: 12min, slurry temperature: ≤45℃; 3. Solid-liquid separation: Continuous centrifugation at 9000 rpm for 10 min; 4. Homogenization: 11000 r / min, 5 min, system temperature ≤40℃.

[0060] For Examples 1-4 above, the quantitative detection data of key active ingredients (mg / 100g, HPLC method) were obtained, and the detection results are shown in Table 1 below: Table 1: HPLC data on the quantitative detection of key active ingredients in the products of Examples 1-4, in mg / 100g; As shown in the table above, the wet ultrafine grinding process of the present invention can stably achieve high catechin enrichment; and the higher the material-to-liquid ratio, the higher the content of EGC and EGCG, and the stronger the antibacterial and antioxidant capacity; at the same time, vitamins and carotene are preserved intact, indicating that the temperature control process throughout the process effectively protects heat-sensitive components.

[0061] For Examples 1-4 above, the antibacterial performance test data (inhibition zone diameter, unit: mm) were obtained: Experimental methods: Microbial challenge test to determine the antibacterial effect against pathogenic bacteria, opportunistic pathogens, and fungi; Table 2: Antibacterial performance test data for products from Examples 1-4, in mm; As shown in Table 2, the product has broad-spectrum natural antibacterial ability and is self-preservative without the need for added preservatives; and as shown in Example 2, the tea tree oil compound can further enhance the antibacterial effect; the present invention has outstanding inhibitory effects on Propionibacterium acnes and MRSA, and is suitable for acne-prone skin and wound care.

[0062] For Examples 1-4 above, stability test data were obtained. The experimental conditions were room temperature and sealed storage for 6 months. The results are shown in Table 3 below: Table 3: Product test data after 6 months of storage at room temperature: As shown in Table 3 above, the product of this invention has excellent room temperature stability, does not separate, deteriorate, or become rancid during long-term storage, and has a high retention rate of active ingredients, fully meeting the storage requirements of cosmetics.

[0063] Based on Examples 1-4 above, the optimal parameters are summarized as follows: 1. Optimal material-liquid ratio: 200–400 g / L. When the material-liquid ratio is below 200 g / L, the active ingredients are too low and the antibacterial effect is insufficient; when the material-liquid ratio is above 400 g / L, the slurry is too viscous, making separation difficult and increasing costs.

[0064] 2. Preferred grinding particle size: 4–6 μm. When the grinding particle size is >6 μm, the cell wall is not broken enough and the components are dissolved in a low amount. When the grinding particle size is <4 μm, the energy consumption is high, separation is difficult, and the membrane is easily blocked.

[0065] 3. Optimal amount of essential oil added: 0.5%–1.0%. When the amount of essential oil added is <0.5%, the aroma is weak and the synergistic effect is not obvious; when the amount of essential oil added is >1.0%, there is a risk of irritation for sensitive skin.

[0066] 4. The process temperature is ≤60℃ throughout, which can effectively prevent the oxidation and degradation of catechins and vitamin C, and effectively improve the activity retention rate.

[0067] A comparative experiment was conducted using the optimal parameters of this invention and existing technologies. The experimental results are shown in Table 4 below: As shown in Table 4 above, the present invention is superior to the prior art in terms of active ingredient content, process efficiency, energy consumption, and natural safety.

[0068] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing an oily cosmetic containing tea leaves, characterized in that, Includes the following steps: Step S1: Provide dried tea leaves and pre-crush the tea leaves to a first average particle size; Step S2: Mix the pre-crushed tea leaves with the oily matrix in a predetermined ratio to obtain a mixed slurry; Step S3: The mixed slurry is finely powdered using a wet ultrafine grinding equipment, so that the tea raw material is further ground to the second average particle size in an oily matrix, which promotes the migration of active ingredients in the tea into the oily matrix; Step S4: Remove insoluble solid residues from the slurry after step S3 and collect the clear oil phase liquid; Step S5: Add natural plant essential oil to the oil phase liquid, mix and homogenize to obtain the oily cosmetic containing tea ingredients.

2. The method for preparing an oily cosmetic containing tea leaves according to claim 1, characterized in that, In step S1, the first average particle size is 10-50 micrometers; in step S3, the second average particle size is 1-10 micrometers; in step S5, the natural plant essential oil is one or more of tea tree essential oil, lavender essential oil, and chamomile essential oil, and the amount of natural plant essential oil added is 0.1%-2% of the mass of the oil phase liquid.

3. The method for preparing an oily cosmetic containing tea leaves according to claim 2, characterized in that, The fine powdering process in step S3 takes 5 to 60 minutes, and the temperature of the mixed slurry is controlled to not exceed 60°C during the process; the grinding disc speed of the wet ultrafine pulverizer is 2000-8000 r / min.

4. The method for preparing an oily cosmetic containing tea leaves according to claim 3, characterized in that, The predetermined ratio mentioned in step S2 is 30g to 800g of tea raw materials per liter of oily matrix; the mixing is carried out under constant temperature conditions of 30-40℃, the stirring rate is 100-300r / min, and the stirring time is 10-30 minutes.

5. The method for preparing an oily cosmetic containing tea leaves according to claim 1, characterized in that, The oily matrix is ​​selected from vegetable oil, mineral oil, synthetic ester oil, or any combination thereof; the vegetable oil is one or more of olive oil, coconut oil, camellia oil, peanut oil, palm oil, jojoba oil, and rapeseed oil; the mineral oil is liquid paraffin, petrolatum, or a combination thereof.

6. The method for preparing an oily cosmetic containing tea leaves according to claim 1, characterized in that, The tea raw material is green tea, black tea, oolong tea, white tea, Pu-erh tea or their processing by-products, and the moisture content of the tea raw material is less than 5%; the active ingredients are one or more of catechin compounds, vitamins, caffeine, and tea aromatic oils.

7. The method for preparing an oily cosmetic containing tea leaves according to claim 1, characterized in that, In step S4, the insoluble solid residue is removed by centrifugation or pressure filtration. When using a continuous centrifuge, the centrifugation speed is 6000 rpm to 13500 rpm and the centrifugation time is 5-20 minutes. When using pressure filtration, the filtration pressure is 0.2-0.8 MPa, and the filter medium is a ceramic membrane with a pore size of 0.1-0.5 micrometers.

8. The method for preparing an oily cosmetic containing tea leaves according to claim 1, characterized in that, The mixing and homogenization in step S5 is carried out using a high-speed shear homogenizer with a homogenization speed of 8000-15000 r / min and a homogenization time of 3-10 minutes. During the homogenization process, the system temperature is controlled to not exceed 40℃.

9. An oil-based cosmetic containing tea extract, characterized in that, The oily cosmetic is prepared by any one of claims 1-8, wherein the oily cosmetic does not contain exogenous emulsifiers, synthetic preservatives and synthetic fragrances, and each 100g of the oily cosmetic contains at least 20mg of epigallocatechin and at least 100mg of epigallocatechin gallate, and the content of natural plant essential oil is 0.1%-2% of the mass of the oily cosmetic.

10. The oily cosmetic containing tea extract according to claim 9, characterized in that, In every 100g of the oily cosmetic product, the content of β-carotene is 7.0-8.0mg, the content of total ascorbic acid is 3.0-6.0mg, the content of total tocopherol is 15.0-16.0mg, and the content of epicatechin is not less than 25mg and the content of epicatechin gallate is not less than 25mg.

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