Antidandruff and bulkiness enhancing raw material based on selenium disulfide and method for its preparation

Abstract

The application discloses a dandruff-removing and bulking hair care raw material based on selenium disulfide and a preparation method thereof, and belongs to the technical field of daily-use cosmetic raw materials. The hair care raw material is mainly composed of "core-shell-crown" structure selenium disulfide composite microspheres, plant synergistic soothing extract, suspension rheological modifier and the like; the composite microspheres take silane-modified selenium disulfide nanocrystals as the core, mesoporous silica / polydopamine hybrid network as the shell, and cationic quaternary ammonium salt-polysiloxane as the crown. The application realizes double-odor adsorption and long-acting slow release through the three-layer structure, solves the industry problem of mutual exclusion between dandruff removal and bulking by means of electrostatic targeted deposition and hydrophobic support mechanism, and simultaneously has excellent storage stability and mild low irritation, and is suitable for various dandruff-removing and bulking hair care terminal products.

Description

Technical Field

[0001] This invention relates to the field of daily chemical products and cosmetic raw materials. Specifically, it relates to an anti-dandruff and volumizing shampoo and conditioner raw material based on selenium disulfide and its preparation method. In particular, it relates to a composite shampoo and conditioner raw material with a "core-shell-crown" three-layer nano / micron-level coating structure that can achieve targeted deposition, long-lasting sustained release, odor masking, and hair root volumizing support, as well as a biomimetic self-assembly preparation process. Background Technology

[0002] An imbalance in the scalp's microecological environment is a major contributing factor to dandruff, scalp itching, and seborrheic dermatitis. Abnormal proliferation of Malassezia and its secreted lipases break down scalp sebum, producing large amounts of free fatty acids (such as oleic acid). This damages the scalp's stratum corneum barrier, leading to abnormal proliferation and shedding of keratinocytes, resulting in visible dandruff. Among numerous anti-dandruff active ingredients, selenium sulfide (SeS2) is widely recognized as one of the most classic and effective anti-dandruff agents due to its strong inhibitory effect on Malassezia and its ability to slow down the turnover rate of scalp epidermal cells. It is widely used in various pharmaceutical and daily chemical personal care products.

[0003] However, selenium disulfide faces the following insurmountable technical bottlenecks in actual formulation applications and consumer experience, which have long constrained the upgrade of the experience of high-end anti-dandruff shampoos and conditioners:

[0004] First, its solubility and dispersibility are extremely poor. Selenium disulfide is an inorganic non-metallic compound that is almost insoluble in water and most organic solvents. In liquid shampoo and conditioner systems, selenium disulfide particles are prone to gravity sedimentation and agglomeration, leading to product stratification, poor stability, and problems such as hard sediment at the bottom and clumping at the nozzle during shelf life. Furthermore, it cannot be evenly distributed on the scalp during use, resulting in either excessively high local concentrations causing irritation or excessively low local concentrations leading to ineffective dandruff removal. Existing technologies often use xanthan gum, carbomer, and acrylate thickeners to create a suspension system, but these only slow down the sedimentation rate and cannot fundamentally solve the particle agglomeration problem. Excessive thickeners can also cause sticky, flat hair after washing.

[0005] Secondly, there is a strong, characteristic odor. Selenium disulfide readily releases free sulfides (such as hydrogen sulfide and sulfur dioxide) in aqueous and surfactant systems, producing an unpleasant "rotten egg" or "sulfur" smell. Existing fragrance masking technologies often fail to completely neutralize this odor, and the mixture of fragrance and sulfides can easily produce even more complex odors, severely impacting the consumer experience. Some encapsulation technologies only achieve physical isolation and are prone to leakage during storage or handling, failing to effectively mask the odor in the long term.

[0006] Third, the contradiction between scalp irritation and dry hair. Selenium disulfide has strong cytotoxicity and degreasing effects; long-term or high-concentration use can damage the scalp's lipid film, leading to dryness, tightness, and redness. To alleviate dryness, traditional formulas often add large amounts of silicone oil (such as polydimethylsiloxane) or heavy oils like higher alcohols. However, this leads to a fourth critical problem.

[0007] Fourth, the incompatibility between dandruff removal and "volume" effects. Modern consumers' demands for hair care products have evolved from simple "cleaning and dandruff removal" to "scalp health and voluminous hair roots." However, silicone oil and heavy oils traditionally used to alleviate the dryness of selenium sulfide easily deposit on the hair and scalp, forming a heavy oil film that causes hair roots to flatten and lie flat against the scalp, completely losing its "volume." Reducing the amount of silicone oil used results in dry, tangled hair with extremely poor combability. How to break the industry curse of "dandruff removal inevitably leads to flatness, and volume inevitably leads to dryness" is a technical problem that urgently needs to be solved in this field.

[0008] To address the above problems, existing technologies have attempted to encapsulate selenium disulfide using microcapsule or liposome technology. For example, a selenium disulfide liposome encapsulation technology has been disclosed in the prior art, which encapsulates selenium disulfide through a phospholipid bilayer to reduce irritation and mask odor. However, this technology has the following drawbacks: (1) Liposomes are prone to demulsification and leakage in shampoos with high temperatures (>45°C) or high surfactant concentrations, and their stability cannot be guaranteed, making it difficult to meet the 2-3 year shelf life requirements of daily chemical products; (2) Liposomes are expensive and have complex preparation processes, making it difficult to apply on a large scale in industrial applications; (3) Liposomes lack the ability to target and adsorb onto the scalp and hair, and are lost in large quantities during rinsing, resulting in low utilization; (4) It cannot solve the problem of hair root fluffiness after washing, and additional conditioning agents are still required, making it impossible to break out of the cycle of "conditioning agents causing flatness".

[0009] In addition, another study disclosed a microsphere technology for encapsulating selenium disulfide in mesoporous silica. Although this improved stability and sustained release, it still had significant drawbacks: the surface of mesoporous silica is rich in silanol groups and is negatively charged. This causes electrostatic repulsion between the silica and the negatively charged damaged hair and scalp, making it difficult for active ingredients to be deposited on the scalp. Most of the active ingredients are lost with rinsing, resulting in low bioavailability. Furthermore, the inorganic silica shell is hard and adheres to the hair strands after washing, increasing the friction between the strands and causing the hair to become dry, lacking smoothness and airiness, and failing to achieve a fluffy and smooth experience.

[0010] In addition, existing research on the modification of selenium disulfide generally focuses only on improving "stability" or "slow-release properties," neglecting the complex rheological environment of the shampoo and conditioner system, the surface charge characteristics of the scalp and hair, and consumers' multiple demands for "voluminous hair roots, no odor, and low irritation." Currently, there is no selenium disulfide composite raw material technology solution that can simultaneously solve the three fundamental problems of sedimentation, odor, and irritation, and completely break the mutually exclusive dilemma of dandruff removal and volume.

[0011] In summary, developing a novel selenium disulfide composite shampoo and conditioner ingredient that, while ensuring efficient dandruff removal, also achieves excellent system stability, long-lasting odor masking, mild and low-irritation properties, and volumizing effect at the hair roots, is a pressing technical problem that needs to be solved in this field. Summary of the Invention

[0012] The purpose of this invention is to address the shortcomings of existing technologies by providing a selenium disulfide-based anti-dandruff and volumizing shampoo and conditioner ingredient and its preparation method. This invention innovatively constructs a three-layer "core-shell-crown" microstructure. A biomimetic composite shell layer of mesoporous silica and polydopamine achieves efficient encapsulation, odor adsorption, and slow-release detoxification of selenium disulfide. The outer cationic-modified polysiloxane "crown" layer utilizes electrostatic adsorption for targeted deposition, while the hydrophobic framework of the polysiloxane forms an "invisible support network" at the hair root, perfectly achieving a four-in-one effect of "powerful dandruff removal, long-lasting odorlessness, gentle soothing, and volumizing at the hair root." The process of this invention is controllable, has good reproducibility, and is suitable for large-scale industrial production.

[0013] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0014] A selenium disulfide-based anti-dandruff and volumizing shampoo and conditioner ingredient, comprising the following components by weight percentage:

[0015] Selenium disulfide composite microspheres (core-shell-crown): 5.0%-25.0%; Plant synergistic soothing extracts: 2.0%-10.0%; Suspension rheology modifier: 0.5%-3.0%; pH adjuster: 0.1%-1.0%; Preservative: 0.1%-0.5%; Deionized water: Balance

[0016] Furthermore, the "core-shell-crown" selenium disulfide composite microspheres comprise, from the inside out, a three-layer structure consisting of a core layer, a shell layer, and a crown layer.

[0017] Core layer: Selenium disulfide nanocrystals with a surface modified with a silane coupling agent;

[0018] Shell: A mesoporous silica / polydopamine composite network layer covering the surface of the core layer;

[0019] Crown: A cationic quaternary ammonium salt-polysiloxane copolymer bonded to the outer surface of the shell by chemical bonds and physical entanglement.

[0020] Preferably, the average particle size of the "core-shell-crown" selenium disulfide composite microspheres is 1.0 μm-5.0 μm, and the Zeta potential is +25 mV to +55 mV. This positive potential design is key to ensuring that the microspheres can be firmly adsorbed onto the negatively charged scalp keratin layer and damaged hair surface, and is also the core structural basis for achieving targeted deposition.

[0021] Preferably, the selenium disulfide nanocrystals have a particle size of 50 nm-200 nm; the silane coupling agent used for surface modification is one or a combination of γ-aminopropyltriethoxysilane (KH550) or γ-glycidoxypropyltrimethoxysilane (KH560). The role of the silane coupling agent is to introduce active reaction sites to the core surface, enhance the interfacial bonding force with the shell, and prevent the shell from detaching.

[0022] Preferably, the mesoporous silica / polydopamine composite network layer is prepared by simultaneously performing the hydrolysis and condensation of tetraethyl orthosilicate (TEOS) and the oxidative self-polymerization of dopamine hydrochloride in a weakly alkaline buffer solution to form an inorganic-organic hybrid shell layer with mesoporous channels and rich in catechol and amino groups. This shell layer not only has an extremely high specific surface area for physical adsorption of sulfide odor molecules, but its polydopamine component can also chemically bond with sulfides through catechol groups, achieving dual physical and chemical odor adsorption; at the same time, polydopamine also provides excellent bioadhesion and shell toughness, preventing the microspheres from breaking during shampooing and rubbing.

[0023] Preferably, the cationic quaternary ammonium salt-polysiloxane copolymer is polyquaternary ammonium salt-10 modified ammonia-terminated polydimethylsiloxane, with an ammonia value of 0.5-2.0 mmol / g and a weight-average molecular weight of 10,000-50,000 Da. This "crown" material combines the targeted adsorption properties of cationic ions with the hydrophobic softness of polysiloxanes, forming hydrophobic support points at the hair roots, increasing the three-dimensional space between hair strands, thereby achieving long-lasting volume.

[0024] Preferably, the plant-based synergistic soothing extract is a quaternary compound extract of Platycladus orientalis leaves, Sapindus mukorossi pericarp, rosemary, and licorice root, prepared using supercritical CO2 extraction combined with enzymatic hydrolysis. This extract is rich in flavonoids, triterpenoid saponins, and caryopsisic acid, which can synergistically inhibit Malassezia with selenium disulfide, while simultaneously inhibiting 5α-reductase activity, reducing excessive scalp sebum secretion, and soothing scalp inflammation.

[0025] Preferably, the suspension rheology modifier is at least one of acrylate / C10-30 alkanol acrylate crosspolymer, xanthan gum, and hydroxypropyl methylcellulose, used to provide yield stress and ensure that the microspheres do not settle during a shelf life of up to 24 months.

[0026] Preferably, the pH adjuster is a citric acid-sodium citrate buffer system, with the final pH value controlled at 5.0-6.0, matching the slightly acidic environment of the scalp and reducing irritation; the preservative is one or more of phenoxyethanol, ethylhexylglycerin, and p-hydroxyacetophenone.

[0027] This invention also provides a method for preparing the above-mentioned selenium disulfide-based anti-dandruff and volumizing shampoo and conditioner raw material, comprising the following steps:

[0028] S1. In-situ synthesis and modification of selenium disulfide nanocrystals (cores): Sodium sulfite and selenium dioxide aqueous solution were subjected to an oxidation-reduction reaction under acidic conditions to generate selenium disulfide precipitate; silane coupling agent was added to the reaction system, and the reaction was carried out at 60-80℃ for 2-4 hours. After centrifugation, washing, and freeze-drying, surface-aminated or epoxy-modified selenium disulfide nanocrystals were obtained.

[0029] S2. Biomimetic coating (shell) of mesoporous silica / polydopamine composite shell: The nanocrystals obtained in step S1 are dispersed in an ethanol-water mixed solvent containing a surfactant (such as CTAB), and the pH is adjusted to 8.0-8.5 by adding tris(hydroxymethyl)aminomethane (Tris) buffer. Tetraethyl orthosilicate (TEOS) and dopamine hydrochloride aqueous solution are added dropwise simultaneously, and the reaction is carried out at 30-40℃ in the dark for 12-24 hours. After the reaction is completed, acidic ethanol solution is added for reflux extraction to remove the template agent CTAB, and the mixture is centrifuged and dried to obtain "core-shell" microspheres with mesoporous structure.

[0030] S3. Grafting modification of the cationic polysiloxane "crown" layer (crown): The "core-shell" microspheres obtained in step S2 are dispersed in isopropanol, and cationic quaternary ammonium salt-polysiloxane copolymer and trace catalyst (such as tetrabutyl titanate) are added. The mixture is refluxed at 70-90℃ for 6-10 hours to allow the active groups on the polysiloxane segments to chemically bond and hydrogen bond entangle with the silanol groups or catechol / amino groups of polydopamine on the shell surface. After cooling, the mixture is centrifuged and washed to obtain "core-shell-crown" selenium disulfide composite microspheres.

[0031] S4. Preparation of Plant Synergistic Soothing Extract: After pulverizing the leaves of Platycladus orientalis, the pericarp of Sapindus mukorossi, rosemary and licorice root, the fat-soluble active substances were extracted by supercritical CO2 at a pressure of 25-35 MPa and a temperature of 40-50℃; the residue was then enzymatically hydrolyzed with cellulase and pectinase to extract water-soluble polysaccharides and saponins; the two extracts were combined, concentrated and sterilized to obtain the plant synergistic soothing extract.

[0032] S5. Raw material compounding and homogenization: Add a suspension rheology modifier to deionized water and disperse at high speed until fully swollen; add the plant extract from step S4 and the "core-shell-crown" selenium disulfide composite microspheres from step S3 in sequence, and emulsify at high shear at 3000-5000 rpm for 15-30 minutes; finally add a pH adjuster and preservative to adjust the pH of the system to 5.0-6.0, defoam, and obtain the washing and care raw material.

[0033] Compared with the prior art, the present invention has the following significant novelty, inventiveness and practicality, and its unexpected technical effects are mainly reflected in the following aspects:

[0034] 1. Novel structural design, three-layer functional synergy, filling a technological gap in the industry.

[0035] This invention is the first to propose a three-layered structure of selenium disulfide composite microspheres: a core layer to ensure an active inner core, a shell layer to achieve slow release and odor adsorption, and a crown layer to achieve targeted deposition and fluffy support. These three layers have clearly defined functions and synergistic effects. Compared to existing technologies that use a single wall material and only address a single problem, this invention presents a completely new architecture at the microstructural level, simultaneously addressing five core requirements: dispersion stability, odor masking, slow and controlled release, targeted deposition, and fluffy smoothness. No similar design exists in existing publicly available technologies in this field, demonstrating outstanding novelty.

[0036] 2. Excellent odor masking and long-lasting sustained-release mechanism, with effects far exceeding expectations.

[0037] This invention innovatively employs a hybrid shell constructed from mesoporous silica and polydopamine to achieve dual odor adsorption through both physical and chemical means: the mesoporous silica has regular nanoscale pores (pore diameter 2-5 nm), and trace amounts of hydrogen sulfide and thiol odor molecules (kinetic diameter approximately 0.3-0.4 nm) released by selenium disulfide are physically trapped by the spatial confinement effect of the pore wall after entering the pores; at the same time, the catechol groups of polydopamine can form hydrogen bonds and chemical bonds with sulfide molecules, strongly "locking" the odor molecules inside the shell.

[0038] Meanwhile, this mesoporous hybrid shell acts as a semi-permeable membrane, allowing moisture and sebum from the scalp surface to slowly penetrate, dissolving trace amounts of selenium disulfide and releasing it slowly through the mesoporous channels. This achieves a sustained-release antibacterial effect lasting 48-72 hours, completely solving the industry pain point of traditional selenium disulfide products having a lingering odor after opening and washing. Testing shows that the sulfide odor response value of this invention's product is only about 3% of that of ordinary selenium disulfide suspensions, with a sensory score approaching zero odor. This effect cannot be achieved by simple physical encapsulation technology, demonstrating significant and unexpected technical benefits.

[0039] 3. Targeted deposition and hair follicle "invisible scaffold" technology breaks down industry technological biases.

[0040] There is a common technical bias in this field: it is believed that to alleviate the dryness of hair caused by selenium disulfide, it is necessary to add heavy conditioning agents such as silicone oil and petrolatum. However, heavy conditioning agents will inevitably cause the hair roots to become flat. Therefore, the idea that "dandruff removal and volume cannot be achieved at the same time" is regarded as an inherent contradiction in the industry.

[0041] This invention completely breaks through this technical bias, achieving a balance between targeted positioning and fluffy support through the cationic quaternary ammonium salt-polysiloxane copolymer of the "crown" layer:

[0042] Targeted deposition: The scalp and damaged hair surfaces carry a negative charge (isoelectric point is about pH 3.6), while the composite microspheres carry a strong positive charge (Zeta potential +25~+55mV). Through electrostatic attraction, they are precisely and quickly targeted and deposited on the scalp and hair roots. The deposition amount in the hair shaft is low, avoiding waste of active ingredients and burden on the hair strands.

[0043] Fluffy Mechanism: The hydrophobic polysiloxane skeleton deposited at the hair roots repels each other and forms microscopic "hydrophobic support nodes" (i.e., invisible scaffolds) between hair strands, significantly increasing the three-dimensional space between hair strands, making the hair roots stand upright and not stick to the scalp; at the same time, the cationic groups neutralize the static electricity of the hair, making the hair ends smooth and tangle-free.

[0044] This invention achieves a three-dimensional hair care effect—effective dandruff removal, long-lasting volume at the roots, and smooth, anti-static hair ends—without using heavy silicone oil. Testing shows that the product increases hair volume by over 50% after washing, and this volume lasts for more than 48 hours. This effect is beyond the reach of those skilled in the art and demonstrates outstanding inventiveness.

[0045] 4. Extremely high system stability and shear resistance, making it highly practical.

[0046] Polydopamine (PDA), hailed as "biomimetic mussel glue," possesses a rich catechol structure that endows the shell with extremely strong cohesiveness and adhesion to the core. During the high-shear pumping, filling, and vigorous agitation processes of shampoo, these "core-shell-crown" microspheres exhibit excellent mechanical strength, remaining undemulsified and leak-proof. Combined with a yield stress system constructed using specific suspension rheology modifiers, the product maintains uniform suspension without stratification or sedimentation even after undergoing alternating high and low temperatures (-15℃ to 48℃) and centrifugation tests at 3000 rpm. It maintains a stable shelf life of over 24 months at room temperature, fully meeting the storage and transportation requirements of daily chemical products.

[0047] 5. Targeted detoxification and synergistic repair of the microecology, resulting in a dual upgrade in safety and efficacy.

[0048] Selenium disulfide is encapsulated within a shell, preventing the cytotoxicity and stinging sensation caused by direct contact of high concentrations of free selenium disulfide with the scalp stratum corneum, thus achieving "targeted release and low irritation across the entire surface." Simultaneously, the plant-based synergistic soothing extracts introduced in this invention contain antioxidants from Platycladus orientalis leaf and rosemary that can eliminate free radicals on the scalp, while Sapindus mukorossi saponins provide gentle, natural cleansing power, and licorice root extract effectively inhibits inflammatory factors. These four plant extracts, together with the slow-released selenium disulfide, form a closed loop of "antibacterial-oil control-anti-inflammatory-repair," improving the scalp microecology from its root cause, rather than simply inhibiting bacteria and removing dandruff.

[0049] Human patch testing has verified that this product is non-irritating to the skin. Long-term use can reduce the transepidermal water loss rate of the scalp and repair the scalp barrier, overturning the stereotype that selenium disulfide is a "strong medicine that will damage the skin".

[0050] 6. The process is highly controllable, has good industrial applicability, and is practical for industrial applications.

[0051] The in-situ synthesis, biomimetic self-assembly, and high-shear emulsification processes used in this invention can all be achieved using conventional equipment commonly used in the fine chemical and daily chemical industries, such as reaction kettles, centrifuges, high-pressure homogenizers, and emulsifiers, without the need for customized and expensive special instruments; the raw materials are widely available, and the core raw materials have mature industrial-grade supply channels, making the cost controllable.

[0052] With a wide process parameter window and good batch reproducibility, this invention can be adapted to different end products by adjusting the amount of microspheres added, making it widely applicable to various product forms such as anti-dandruff and volumizing shampoos, scalp cleansing creams, and oil-controlling and anti-dandruff shampoo gels. Compared with advanced encapsulation technologies such as liposomes and microfluidics, this invention has lower industrial scale-up difficulty and higher production efficiency, possessing extremely high mass production value and commercial application prospects. Attached Figure Description

[0053] Figure 1 This is a process flow diagram of the preparation process of the anti-dandruff and fluffing shampoo and conditioner raw material based on selenium disulfide according to the present invention.

[0054] Figure 2 This diagram illustrates the preparation process of the plant-based synergistic soothing extract and its multi-target synergistic mechanism. Detailed Implementation

[0055] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0056] Unless otherwise specified, the experimental methods described in the following examples were generally performed under standard conditions or as recommended by the manufacturer. All raw materials used are commercially available unless otherwise specified.

[0057] (I) Implementation Examples

[0058] Example 1

[0059] The washing and care ingredients provided in this embodiment, by weight percentage, include the following components:

[0060] Selenium disulfide composite microspheres (core-shell-crown): 15.0%; Plant synergistic soothing extract: 5.0%; Acrylic acid (ester) / C10-30 alkanol acrylate crosspolymer (suspension rheology modifier): 1.5%; Xanthan gum: 0.2%; Citric acid (pH adjuster): appropriate amount (adjust to pH 5.5); Phenoxyethanol / ethylhexylglycerin (preservative): 0.3%; Deionized water: balance (to 100%).

[0061] The preparation method is as follows:

[0062] S1. In-situ synthesis and modification of selenium disulfide nanocrystals (nuclei)

[0063] In a stirred and temperature-controlled reactor, 100 g of selenium dioxide (SeO2) was dissolved in 2000 mL of deionized water, and 5 mL of concentrated hydrochloric acid was added to adjust the pH to 2.0. An aqueous solution containing 150 g of sodium sulfite (Na2SO3) was slowly added dropwise at 40 °C, and the reaction was allowed to proceed for 2 hours, producing an orange-red selenium disulfide precipitate. Subsequently, 15 g of γ-aminopropyltriethoxysilane (KH550) was added to the system, and the temperature was raised to 70 °C with stirring for 3 hours. After the reaction was complete, the product was centrifuged (8000 rpm, 10 min), washed three times alternately with deionized water and anhydrous ethanol, and freeze-dried to obtain surface-aminated selenium disulfide nanocrystals (average particle size approximately 120 nm).

[0064] S2. Biomimetic coating (shell) of mesoporous silica / polydopamine composite shell.

[0065] 50 g of the nanocrystals obtained in step S1 were ultrasonically dispersed in 1000 mL of an ethanol-water mixture (3:1 volume ratio) containing 5 g of cetyltrimethylammonium bromide (CTAB). The pH of the system was adjusted to 8.5 with Tris-HCl buffer. Under light-protected conditions at 35 °C, 100 mL of tetraethyl orthosilicate (TEOS) and 100 mL of an aqueous solution containing 10 g of dopamine hydrochloride were simultaneously added dropwise at a flow rate of 2 mL / min using a dual-channel microinjection pump. After the addition was complete, the reaction was continued with constant temperature stirring for 18 hours. After the reaction was complete, 500 mL of an ethanol solution containing 1% HCl was added, and the mixture was refluxed at 60 °C for 6 hours to remove the template agent CTAB. The microspheres were centrifuged, washed, and vacuum dried to obtain core-shell microspheres with a mesoporous structure.

[0066] S3. Grafting modification of cationic polysiloxane "crown" layer (crown)

[0067] 50g of the core-shell microspheres obtained in step S2 were dispersed in 500mL of isopropanol, and 30g of polyquaternium-10 modified ammonia-terminated polydimethylsiloxane (ammonia value 1.2mmol / g, weight-average molecular weight 25000Da) and 0.5g of tetrabutyl titanate catalyst were added. Under nitrogen protection, the mixture was refluxed at 80℃ for 8 hours. After cooling, the mixture was centrifuged, washed with isopropanol to remove unreacted polysiloxane, and vacuum dried to obtain core-shell-crown selenium disulfide composite microspheres. The average particle size of the microspheres was measured to be 2.8μm using a laser particle size analyzer and a Zeta potential analyzer, and the Zeta potential was +42mV.

[0068] S4. Preparation of plant-based synergistic soothing extracts

[0069] Weigh dried arborvitae leaves, soapberry pericarp, rosemary, and licorice root in a mass ratio of 3:2:2:1, and pulverize them through a 40-mesh sieve. Place the powder in a supercritical CO2 extraction vessel and extract for 3 hours at a pressure of 30 MPa, a temperature of 45°C, and a CO2 flow rate of 20 L / h. Collect the fat-soluble extract. Remove the residue, add 10 times the amount of deionized water, adjust the pH to 5.0, add 1% cellulase and 0.5% pectinase by mass, and enzymatically hydrolyze at 50°C for 4 hours. After enzyme inactivation, filter, and concentrate the filtrate under reduced pressure to 1 / 5 of the original volume. Emulsify and combine the fat-soluble extract and the water-soluble concentrate using a high-pressure homogenizer (100 MPa), sterilize, and obtain a synergistic plant-based soothing extract.

[0070] S5. Raw material blending and homogenization

[0071] Acrylic (ester) / C10-30 alkanol acrylate crosspolymer and xanthan gum were added to deionized water and stirred at 800 rpm for 2 hours to swell. The plant extract from step S4 and the "core-shell-crown" selenium disulfide composite microspheres from step S3 were added sequentially, and high-shear emulsification was performed at 4000 rpm for 20 minutes. Finally, citric acid was added to adjust the pH to 5.5, preservatives were added, and the mixture was defoamed under vacuum to obtain the washing and care raw material of Example 1.

[0072] Examples 2-5

[0073] The only difference between Examples 2-5 and Example 1 is the amount of "core-shell-crown" selenium disulfide composite microspheres and plant extracts added, as well as the fine-tuning of some process parameters. The specific formulas and parameters are shown in Table 1.

[0074] Table 1 Comparison of formulations and key process parameters in Examples 1-5

[0075] sheet

[0076] "Core-shell-crown" microspheres (%) 15.0 5.0 25.0 10.0 20.0 Plant synergistic extract (%) 5.0 2.0 10.0 8.0 4.0 Suspension rheology modifier (%) 1.7 0.5 3.0 1.2 2.0 S1 Nanocrystal size (nm) 120 50 200 80 150 S2 Reaction pH 8.5 8.0 9.0 8.2 8.8 S3 Polysiloxane amine value 1.2 0.5 2.0 0.8 1.5 Final microspheres Zeta potential (mV) +42 +28 +55 +35 +48 Final system pH 5.5 5.0 6.0 5.2 5.8

[0077] (ii) Comparative Example

[0078] To verify the inventiveness of the technical solution of this invention and the indispensability of each structural layer, the following comparative examples are provided:

[0079] Comparative Example 1: Polydopamine component missing from the "shell" layer

[0080] The preparation method is the same as in Example 1, except that in step S2, dopamine hydrochloride is not added; instead, TEOS is hydrolyzed to generate a pure mesoporous silica shell to coat selenium disulfide nanocrystals. Subsequent steps are the same. This comparative example aims to verify the effects of polydopamine on shell toughness, odor adsorption, and the grafting strength of the "crown" layer.

[0081] Comparative Example 2: No "crown" layer (without cationic polysiloxane modification)

[0082] The preparation method is the same as in Example 1, except that step S3 is omitted, and the core-shell microspheres (with negative surface charge) obtained in step S2 are directly used for compounding in step S5. This comparative example aims to verify the targeted deposition of positive charge on the crown layer and the decisive role of polysiloxane in the volume of hair roots.

[0083] Comparative Example 3: Traditional liposome encapsulation of selenium disulfide

[0084] Selenium disulfide liposomes were prepared using a conventional method: soybean lecithin, cholesterol, and selenium disulfide powder were dissolved in ethanol, rotary evaporated to form a film, hydrated, and homogenized under high pressure to obtain liposomes. These liposomes were then added to the formulation, replacing the core-shell-corona microspheres in Example 1. This comparative example represents existing high-end encapsulation technology.

[0085] Comparative Example 4: Commercially available selenium disulfide suspension

[0086] Commercially available cosmetic-grade selenium disulfide (average particle size 5μm) without any encapsulation or modification is added to the formulation via simple xanthan gum suspension. This represents a traditional low-end anti-dandruff ingredient.

[0087] Comparative Example 5: Lack of Plant Synergistic Soothing Extract

[0088] The preparation method is the same as in Example 1, except that no plant-based synergistic soothing extracts are added to the formula, and deionized water is used to make up the remaining volume. This aims to verify the effects of plant extracts in synergistic dandruff removal, oil control, and soothing and anti-inflammatory effects.

[0089] (III) Performance Testing and Effect Verification

[0090] To objectively and scientifically evaluate the technical effects of the embodiments and comparative examples of this invention, the inventors designed rigorous tests in the following five dimensions. All tests were conducted in a third-party daily chemical testing laboratory with CNAS accreditation or a human efficacy evaluation institution that meets GCP standards.

[0091] Test Example 1: Physicochemical Stability and Suspension Test

[0092] Test method:

[0093] The raw material samples of Examples 1-5 and Comparative Examples 1-5 were respectively placed into 100mL transparent glass graduated tubes and sealed. (1) Centrifugation test: Centrifuge at 3000rpm for 30 minutes and observe whether there is stratification or precipitation. (2) High and low temperature alternation test: Freeze at -15℃ for 24h, take it out and place it at room temperature for 2h, and then place it in a constant temperature oven at 48℃ for 24h, which is one cycle. After 10 consecutive cycles, observe the appearance and sedimentation. (3) Long-term room temperature standing: Stand at room temperature (25±2℃) for 12 months and record the sedimentation height ratio (sedimentation layer height / total height×100%).

[0094] Test results:

[0095] Examples 1-5: No stratification was observed during centrifugation; the system was homogeneous after 10 cycles of high and low temperatures, with no demulsification or sedimentation; after 12 months of standing at room temperature, the sedimentation height ratio was <2% (it exhibited a very slight, uniform network suspension that dispersed upon shaking).

[0096] Comparative Example 1 (pure silicon shell): After three cycles of high and low temperatures, obvious hard sedimentation appeared at the bottom, with a sedimentation height ratio of 15%. This indicates that the lack of adhesion and toughness of polydopamine caused the pure inorganic silicon shell to crack under the action of thermal expansion and contraction and surfactants, resulting in selenium disulfide leakage and agglomeration sedimentation.

[0097] Comparative Example 3 (liposomes): Severe stratification (demulsification) occurred after two cycles of high and low temperatures. Liposomes are extremely unstable under extreme temperatures and high shear.

[0098] Comparative Example 4 (Ordinary Suspension): After 12 months of static settling, the settling height reached 45%, forming a dense and hard bottom that was difficult to redisperse.

[0099] Conclusion: The "core-shell-crown" structure of this invention, combined with the biomimetic adhesion of polydopamine and specific rheology modifiers, endows the system with extremely excellent shear resistance and thermodynamic stability, completely solving the industry problem of easy sedimentation of selenium disulfide.

[0100] Test Example 2: In vitro antibacterial, odor masking and sustained-release performance tests

[0101] Test method:

[0102] (1) Antibacterial rate test: Malassezia furfur (ATCCMYA-3635) was used. The antibacterial rate and minimum inhibitory concentration (MIC) of each group were determined at 24h and 72h by agar plate perforation method and micro-broth dilution method.

[0103] (2) Odor sensory and electronic nose test: 10 professional odor judges conducted blind tests (1-10 points, 10 points for no odor); at the same time, the response value of the sulfide sensor (W1W, W2W) was detected by the PEN3 electronic nose system.

[0104] (3) In vitro sustained release test: The cumulative release rate of selenium disulfide was measured at 2h, 24h, 48h and 72h using artificial selenium (containing oleic acid, squalene and other substances) as receiving liquid in a Franz diffusion cell.

[0105] Table 2 Results of Antibacterial, Odor, and Slow-Release Performance Tests

[0106] sheet

[0107] Example 1 98.5 99.2 9.2 1.5 45.6 Example 3 99.1 99.5 8.8 1.8 52.3 Comparative Example 1 95.2 82.1 5.5 12.4 88.5 (spike) Comparative Example 2 96.0 97.5 9.0 1.6 48.2 Comparative Example 3 97.5 85.4 6.5 8.5 75.0 Comparative Example 4 99.8 99.8 2.1 45.6 100 (instant)

[0108] In-depth data analysis:

[0109] 1. Verification of Odor Masking Mechanism: Comparative Example 4 (naked drug) had an extremely strong sulfide odor; Comparative Example 1 (pure silicon shell) failed to mask the odor due to the lack of chemical bonding and adsorption of hydrogen sulfide by the catechol groups of polydopamine, and the fragility of the pure silicon shell. Example 1, through the dual mechanism of mesoporous physical confinement and polydopamine chemical adsorption, reduced the sulfide response value to an extremely low level (1.5), achieving a sensory score as high as 9.2, thus achieving "olfactory invisibility." The effect of this dual adsorption mechanism far exceeded the expectations of single physical encapsulation.

[0110] 2. Slow-release and long-lasting antibacterial effect: Comparative Example 4 showed instantaneous release, while Comparative Examples 1 and 3 experienced burst release (>70%) within 24 hours, leading to a sharp drop in the antibacterial rate in the later stages (72 hours). The mesoporous hybrid shell of Example 1 acted as a perfect "controlled-release valve," with a cumulative release rate of only 45.6% over 72 hours, maintaining a long-lasting MIC concentration on the scalp surface. The antibacterial rate remained as high as 99.2% over 72 hours, achieving an upgraded experience of long-lasting dandruff removal with just one shampoo.

[0111] Test Example 3: Hair Bundle Fluffiness, Combing Ability, and Targeted Deposition Test

[0112] Test method:

[0113] (1) Hair bundle fluffiness test: Healthy and damaged hair bundles (10g in weight and 20cm in length) from Asians were selected and washed with shampoos prepared in the example and comparative proportions (the raw materials were added at 15% to prepare regular shampoo) and air-dried. The three-dimensional volume (cm³) of the hair bundle was measured using a 3D laser scanner. The larger the volume, the better the fluffiness.

[0114] (2) Wet / dry hair combability: The combing power (J) was measured using the Dia-StronMTT175 hair tester. The smaller the combing power, the smoother the hair.

[0115] (3) Targeted deposition rate: The hair strands and simulated scalp (Vitro-Skin) after shampooing were digested with nitric acid, and the selenium (Se) content was determined by ICP-MS. The deposition retention rate (%) of selenium disulfide was calculated.

[0116] Table 3 Results of tests on fluffiness, combability, and deposition rate

[0117] sheet

[0118] Example 1 385 (extremely fluffy) 0.045 32.5 18.2 Example 2 340 0.052 24.1 14.5 Comparative Example 1 210 (flattened) 0.180 (dry) 8.5 5.2 Comparative Example 2 235 (flattened) 0.155 10.2 6.8 Comparative Example 3 280 0.085 15.4 12.1 Comparative Example 4 190 (extremely flattened) 0.220 45.6 35.5 Blank base 250 0.120 0 0

[0119] In-depth data analysis and mechanism derivation:

[0120] 1. Targeted deposition driven by electrostatics: The scalp and damaged hair are negatively charged. The microspheres in Comparative Examples 1 and 2 have negative or weakly negative charges on their surfaces, generating electrostatic repulsion with the hair, resulting in significant loss during rinsing (scalp deposition rate <11%). The "crown" layer of Example 1 carries a strong positive charge (+42mV), precisely adhering to the scalp and hair strands like a magnet, achieving a scalp deposition rate as high as 32.5%, ensuring that the anti-dandruff ingredients truly act on the lesions and significantly improving bioavailability.

[0121] 2. Perfect Balance of Fluff and Smoothness: Although Comparative Example 4 had a high deposition rate, the large number of exposed selenium disulfide inorganic particles increased the friction between hair strands (combing work 0.220), leading to dry and tangled hair. Furthermore, the heavy particles compressed the hair roots, resulting in a volume of only 190 cm³. Comparative Example 1, with its pure silicone shell, also resulted in dryness. The core breakthrough of this invention lies in the cationic polysiloxane "crown" layer deposited at the hair roots in Example 1. Its hydrophobic siloxane framework creates a microscopic hydrophobic repulsion effect between hair strands, significantly reducing combing work (0.045, extremely smooth) and forming physical support nodes at the hair root intersections, making the hair roots stand upright and increasing the hair bundle volume to 385 cm³, achieving an unprecedented three-in-one effect of "dandruff removal + fluffiness + smoothness." This effect completely breaks the technical prejudice in the field that "dandruff removal inevitably leads to flatness," possessing significant and unexpected technical benefits.

[0122] Test Example 4: Evaluation of Human Efficacy (Dandruff Removal, Oil Control, Soothing)

[0123] Test method:

[0124] 120 volunteers (half male and half female, aged 18-45 years) with moderate to severe dandruff and scalp itching were recruited and randomly divided into 6 groups (Example 1 group, Comparative Example 3 group, Comparative Example 4 group, Comparative Example 5 group, a commercially available international brand selenium disulfide shampoo group, and blank control group), with 20 people in each group. The corresponding sample was used to wash hair 3 times a week for 4 consecutive weeks. (1) Dandruff removal rate: The amount of dandruff shed was measured by the SquameScan instrument (D-Squame tape method). (2) Oil control rate: The amount of sebum secretion on the scalp was measured by the Sebumeter SM815. (3) Itching and erythema scores: Visual analog scale (VAS, 0-10 points) were performed by dermatologists.

[0125] Table 4. Results of clinical efficacy evaluation in humans over 4 weeks (mean values)

[0126] sheet

[0127] Example 1 92.5 68.4 8.5 85.0 0% Comparative Example 3 75.2 35.2 5.2 45.0 5% (slight stinging) Comparative Example 4 88.5 20.5 4.0 20.0 25% (dry / stinging) Comparative Example 5 80.1 42.1 5.5 50.0 0% Commercial brand 85.0 45.0 6.5 60.0 10%

[0128] In-depth data analysis:

[0129] 1. Synergistic effect of dandruff removal and oil control: Example 1 showed a significantly higher dandruff reduction rate (92.5%) and sebum reduction rate (68.4%). This is attributed to the slow-release and long-lasting antibacterial effect of selenium disulfide, the gentle cleansing effect of Sapindus mukorossi saponins in the plant extracts, and the inhibitory effect of Platycladus orientalis / rosemary on 5α-reductase, thus breaking the vicious cycle of "oil secretion - Malassezia reproduction - dandruff production" at its source. Comparative Example 5, lacking plant extracts, showed a significant decrease in oil control rate, demonstrating the indispensability of the quaternary plant synergistic system.

[0130] 2. Extremely gentle and soothing: Comparative Example 4 (bare medication) had an adverse reaction rate as high as 25% (stirring, tightness) due to direct stimulation of the stratum corneum. Example 1, through "core-shell" physical isolation and the potent anti-inflammatory effect of licorice root extract, reduced the adverse reaction rate to 0% and achieved an erythema reduction rate of up to 85.0%, completely overturning the stereotype that traditional selenium sulfide is "a strong medicine that will damage the skin".

[0131] Test Example 5: Human Patch and Scalp Barrier Repair Test

[0132] Test method:

[0133] A closed patch test was used, in which the raw material solution of Example 1 was applied to the sensitive areas on the back and behind the ears of volunteers for 48 hours, and the stimulation response was observed. At the same time, the transepidermal water loss (TEWL) of the scalp was measured before and after 4 weeks of use of the shampoo of Example 1 using a Tewameter™ 300 to assess the barrier repair capacity.

[0134] Results: The patch test result of Example 1 was "Grade 0 (no irritation)," demonstrating its extremely high safety. After 4 weeks of use, the TEWL value of the volunteers' scalp decreased significantly from 18.5 g / (h・m²) at baseline to 11.2 g / (h・m²) (P<0.01), indicating that the present invention not only does not damage the barrier, but also promotes the self-repair of the scalp stratum corneum barrier through plant polysaccharides and a sustained-release mechanism.

[0135] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention. Those skilled in the art should understand that, based on the "core-shell-crown" targeted deposition and hydrophobic support mechanism disclosed in this specification, its application to the modification of other poorly soluble inorganic active ingredients (such as pyrrolidone ethanolamine salt, clomiphene, etc.) and in the formulation of washing and conditioning products falls within the scope of protection of the present invention.

Claims

1. A selenium disulfide-based anti-dandruff and volumizing shampoo and conditioner ingredient, characterized in that: It consists of the following components by mass percentage: "Core-shell-crown" selenium disulfide composite microspheres: 5.0%~25.0%; Plant-based synergistic soothing extracts 2.0%~10.0%; Suspension rheology modifier 0.5%~3.0%; pH adjuster 0.1%~1.0%; Preservatives: 0.1%~0.5%; Add deionized water to make up the remaining amount; The "core-shell-crown" selenium disulfide composite microspheres consist of a core layer, a shell layer, and a crown layer from the inside out: the core layer is selenium disulfide nanocrystals with a surface modified by a silane coupling agent; the shell layer is a mesoporous silica / polydopamine composite network layer covering the surface of the core layer; and the crown layer is a cationic quaternary ammonium salt-polysiloxane copolymer grafted onto the outer surface of the shell layer through chemical bonds and physical entanglement.

2. The selenium disulfide-based anti-dandruff and volumizing shampoo and conditioner raw material according to claim 1, characterized in that: The "core-shell-crown" selenium disulfide composite microspheres have an average particle size of 1.0 μm to 5.0 μm and a zeta potential of +25 mV to +55 mV.

3. The selenium disulfide-based anti-dandruff and volumizing shampoo and conditioner raw material according to claim 1, characterized in that: The selenium disulfide nanocrystals have a particle size of 50 nm to 200 nm; the silane coupling agent is one or a combination of two of γ-aminopropyltriethoxysilane or γ-glycidoxypropyltrimethoxysilane.

4. The selenium disulfide-based anti-dandruff and volumizing shampoo and conditioner raw material according to claim 1, characterized in that: The mesoporous silica / polydopamine composite network layer is formed by the simultaneous reaction of tetraethyl orthosilicate hydrolysis condensation and dopamine hydrochloride oxidation self-polymerization, and the shell has mesoporous channels with a pore size of 2nm~5nm inside.

5. The selenium disulfide-based anti-dandruff and volumizing shampoo and conditioner raw material according to claim 1, characterized in that: The cationic quaternary ammonium salt-polysiloxane copolymer is polyquaternary ammonium salt-10 modified ammonia-terminated polydimethylsiloxane, with an ammonia value of 0.5~2.0 mmol / g and a weight-average molecular weight of 10000~50000 Da.

6. The selenium disulfide-based anti-dandruff and volumizing shampoo and conditioner raw material according to claim 1, characterized in that: The plant-based synergistic soothing extract is a quaternary compound extract of Platycladus orientalis leaves, Sapindus mukorossi pericarp, rosemary and licorice root, prepared using supercritical CO2 extraction combined with compound enzymatic hydrolysis technology.

7. The selenium disulfide-based anti-dandruff and volumizing shampoo and conditioner raw material according to claim 1, characterized in that: The suspension rheology modifier is at least one of acrylate / C10-30 alkanol acrylate crosspolymer, xanthan gum, and hydroxypropyl methylcellulose; the pH adjuster is a citric acid-sodium citrate buffer system with a final pH of 5.0-6.0; and the preservative is one or more of phenoxyethanol, ethylhexylglycerin, and p-hydroxyacetophenone.

8. A method for preparing a selenium disulfide-based anti-dandruff and volumizing shampoo and conditioner raw material as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. In-situ synthesis and modification of selenium disulfide nanocrystals: Sodium sulfite and selenium dioxide aqueous solution were reacted under acidic conditions to generate selenium disulfide precipitate. A silane coupling agent was added and reacted at 60~80℃ for 2~4 hours. After centrifugation, washing and freeze drying, surface-modified selenium disulfide nanocrystals were obtained. S2. Biomimetic coating of mesoporous silica / polydopamine composite shell: The nanocrystals obtained in step S1 are dispersed in an ethanol-water mixed solvent containing surfactant, the pH is adjusted to 8.0~8.5, and tetraethyl orthosilicate and dopamine hydrochloride aqueous solution are added dropwise simultaneously. The reaction is carried out at 30~40℃ in the dark for 12~24 hours. After template removal and centrifugation and drying, "core-shell" microspheres are obtained. S3. Grafting modification of cationic polysiloxane crown: The core-shell microspheres were dispersed in isopropanol, and cationic quaternary ammonium salt-polysiloxane copolymer and catalyst were added. The mixture was refluxed at 70~90℃ for 6~10 hours. After centrifugation and washing, selenium disulfide composite microspheres were obtained. S4. Preparation of plant synergistic soothing extract: The raw plant material is crushed and then extracted with supercritical CO2 to extract the fat-soluble active substances. The residue is extracted with compound enzymatic hydrolysis to extract the water-soluble components. The extracts are combined, concentrated and sterilized to obtain plant synergistic soothing extract. S5. Raw material compounding and homogenization: The suspension rheology modifier is dispersed and swollen in deionized water, and then plant synergistic soothing extract and composite microspheres are added in sequence. After high shear emulsification, the pH is adjusted, preservatives are added, and defoaming is performed to obtain the final product.

9. The preparation method according to claim 8, characterized in that, In step S2, the surfactant is hexadecyltrimethylammonium bromide, and the template agent is removed by acidic ethanol reflux extraction after the reaction is completed.

10. The preparation method according to claim 8, characterized in that, In step S4, the supercritical CO2 extraction pressure is 25~35MPa and the temperature is 40~50℃; the compound enzymatic hydrolysis uses a combination of cellulase and pectinase, and the enzymatic hydrolysis temperature is 45~55℃.

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