A keratin-binding microcapsule, a preparation method and application thereof

Abstract

The present application relates to a kind of keratin bonding microcapsules and its preparation method and application, belong to the field of cosmetics.The microcapsules of the present application include maleic acid diethylhexyl ester, keratin amino acid, hydrolyzed keratin as the main active ingredient of capsule core, constitute keratin bonding agent, as keratin reconstruction complex;Capsule wall is double-layer structure: inner layer is formed by the three-dimensional network of hydrolyzed keratin, keratin amino acid and hydrophilic polymer interface self-assembly;Outer layer is the dense polymer film of acrylate monomer and crosslinking agent copolymerization.The microcapsules of the present application can be applied in hair straightening agent, hair dye or hair care product, target repair the disulfide bond broken in the process of dyeing, reverse keratin damage, repair damaged hair, improve hair break strength, reduce broken hair.

Description

Technical Field

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

[0002] In the process of perming or dyeing hair, alkaline reagents (such as ammonia) or strong oxidants (such as hydrogen peroxide) cause the hair cuticle to open. This process is essentially keratin denaturation. On the one hand, it manifests as cuticle damage: the keratin layer structure loosens, leading to the loss of surface protective function; on the other hand, it damages the hair cortex: the disulfide bonds (-SS-) of the keratin chain break to form thiol groups (-SH), which twists and deforms the internal fiber network, reducing the strength of the hair and making it easy to break.

[0003] Current hair care products mainly rely on two types of technologies: First, by adding silicone-based conditioning agents (such as polydimethylsiloxane), a physical film is formed on the hair cuticle surface, improving smoothness by reducing the coefficient of friction. Second, cationic conditioning agents (such as quaternary ammonium salts) are added to smooth out hair cuticle curling through electrostatic adsorption. CN201711274300.9 discloses a hair conditioner and its preparation method. The hair conditioner is mainly made of a variety of raw materials, which, by weight, include 0.5-10 parts of amino silicone oil microemulsion, 2-11 parts of siloxane polymer, 4.3-14.5 parts of oil phase mixture, and 95-115 parts of aqueous phase mixture. This hair conditioner can alleviate the problems of traditional pure amino silicone oil, such as excessive viscosity making it difficult to disperse, and excessively large particles causing uneven adhesion and insufficient smoothness on the hair surface. The positive charge of the amino functional groups of amino silicone oil has an affinity for keratin, which can adjust and care for hair strands. This invention offers significant advantages in terms of heat protection for hair strands, enhancing hair shine and smoothness, improving dry and wet combing, and increasing hair volume. CN200880017185.X discloses a hair conditioning composition comprising: (a) a quaternized siloxane polymer; (b) a grafted siloxane copolyol; (c) a cationic surfactant system containing a dialkyl quaternized ammonium salt cationic surfactant; (d) a high-melting-point aliphatic compound; and (e) an aqueous carrier. This invention can utilize conditioning compositions containing dialkyl quaternized ammonium salt cationic surfactants to provide improved conditioning benefits, such as smoothness and reduced friction.

[0004] The inherent defects of the above hair care products are: (1) The repair of hair only stays on the surface: Silicone oil forms a film on the surface of the hair cuticle, which can bring immediate smoothness and anti-frizz effect, but due to its large molecular weight, it cannot penetrate into the hair cortex. It only treats the symptoms and not the root cause, and cannot truly repair damaged hair. Moreover, it is not easy to wash off completely, and it is easy to accumulate, increasing the burden on the scalp. (2) It cannot rebuild disulfide bonds: It lacks a repair mechanism that targets the -SH group and has no reversible effect on hair cortex damage.

[0005] Therefore, there is an urgent need to develop a new hair care technology that can penetrate the hair cuticle barrier, target and repair disulfide bonds, and permanently reverse keratin damage. Summary of the Invention

[0006] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a keratin-bonded microcapsule agent, its preparation method, and its application. It aims to solve the problems of how to precisely deliver repair components to damaged areas of the hair cortex and how to rebuild disulfide bonds to reverse keratin damage.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] In a first aspect, the present invention provides a keratin-bonded microcapsule agent, characterized in that it comprises the following components in parts by weight:

[0009] 15-30 parts of diethylhexyl maleate;

[0010] 10-25 parts of keratin amino acids;

[0011] 5-10 parts hydrolyzed keratin;

[0012] 25-50 parts of carrier solvent;

[0013] 2-5 parts of hydrophilic polymer;

[0014] 5-10 parts of acrylate monomer;

[0015] Crosslinking agent 0.5-2 parts;

[0016] Initiator 0.5-1 part;

[0017] 1-2 parts of curing agent;

[0018] 5-10 parts emulsifier;

[0019] Stabilizer 0.5-1.5 parts;

[0020] 60-120 parts deionized water;

[0021] The hydrophilic polymer is polyethylene glycol with a molecular weight of 4000-10000 Da.

[0022] The keratin-binding microcapsule contains three core active ingredients: diethylhexyl maleate, keratin amino acids, and hydrolyzed keratin, forming a keratin binding agent as a keratin rebuilding complex. The three components achieve fundamental damage reversal through spatial hierarchical repair, synergistically repairing damaged keratin. Hydrolyzed keratin (surface layer): forms a β-sheet membrane on the hair cuticle, reducing friction; diethylhexyl maleate (middle layer): penetrates the hair cuticle, linking keratin chains through ionic bonds; keratin amino acids (deep layer): enters the hair cortex, rebuilding disulfide bonds through thiol groups.

[0023] Diethylhexyl maleate: It links adjacent keratin chains by forming ionic bonds with the amino groups (-NH2) of keratin through the carboxyl group (-COOH). It reverses the keratin chain breakage caused by bleaching / perming, thereby increasing the elastic modulus of the hair cortex and reversing keratin damage.

[0024] Keratin amino acids: The keratin amino acids of this invention are thiol-containing amino acids, which are selected from one or more of cysteine, N-acetylcysteine, and cysteine ​​hydrochloride. Low molecular weight amino acids are transdermally absorbed into the hair cortex through the cuticle space, replenishing keratin synthesis precursors, rebuilding the disulfide bond network, and co-constituted with diethylhexyl maleate to reconstitute the hair cortex keratin chain.

[0025] Hydrolyzed keratin: A product obtained from enzymatic / chemical hydrolysis of keratin, with a molecular weight of 2000-5000 Da. It forms a β-fold hydrophobic film on the hair cuticle surface. It physically smooths the warped hair cuticles, causing them to close, reducing the coefficient of friction during combing, and thus, in conjunction with diethylhexyl maleate and keratin amino acids, restores the mechanical strength of the hair.

[0026] Preferably, the carrier solvent is selected from isopropyl myristate and / or caprylic / capric triglyceride.

[0027] More preferably, the hydrophilic polymer is polyethylene glycol with a molecular weight of 4000-10000 Da; the acrylate monomer is butyl acrylate or methyl methacrylate; and the crosslinking agent is N,N'-methylenebisacrylamide.

[0028] Preferably, the emulsifier is selected from polyvinyl alcohol, poloxamer, or sodium dodecyl sulfate; the stabilizer is selected from sodium alginate or carboxymethyl cellulose; the initiator is ammonium persulfate or potassium persulfate; and the curing agent is CaCl2 or aluminum sulfate.

[0029] In a second aspect, the present invention provides a method for preparing a keratin-bonded microcapsule as described in the first aspect, characterized by comprising the following steps:

[0030] (1) Preparation of oil phase: Diethylhexyl maleate, keratin amino acids, hydrolyzed keratin, and carrier solvent are mixed and dissolved at 50-70℃ to obtain oil phase;

[0031] (2) Preparation of aqueous phase: Dissolve emulsifier and stabilizer in deionized water, and adjust pH to 4.0-6.0 with 10% citric acid solution to obtain aqueous phase;

[0032] (3) Emulsification: The oil phase is injected into the aqueous phase and homogenized at 8000-12000 rpm for 2-5 minutes to obtain an emulsion;

[0033] (4) Interface self-assembly: Add hydrophilic polymer to the emulsion and stir at 55-65℃ for 1-2 hours;

[0034] (5) Polymerization and curing: Add acrylate monomers, crosslinking agents and initiators to the emulsion and react at 55-65℃ for 1-3 hours;

[0035] (6) Post-curing: Add curing agent to emulsion, stir at 20-30℃ for 1-2 hours, collect microcapsules by centrifugation, and obtain microcapsule agent by spray drying.

[0036] Thirdly, the present invention provides the use of microencapsulation agents as described in the first aspect or microencapsulation agents prepared by the preparation method described in the second aspect in the preparation of hair-use compositions.

[0037] Fourthly, the present invention provides a hair-applied composition comprising 0.5-5 wt% of the microcapsule as described in the first aspect or the microcapsule prepared by the method described in the second aspect, wherein the hair-applied composition has a pH of 7.0-10.0.

[0038] Preferably, the hair composition includes any one of a perming agent, a hair dye, or a hair care product.

[0039] The microcapsule of this invention has a bilayer structure: the inner layer is a three-dimensional network formed by the self-assembly of hydrolyzed keratin, keratin amino acids, and a hydrophilic polymer at the interface; the outer layer is a dense polymer film formed by the copolymerization of acrylate monomers and a crosslinking agent. Hydrolyzed keratin and the hydrophilic polymer form the inner three-dimensional network at the oil-water interface through adsorption of hydrophobic regions and hydrogen bonding, while keratin amino acids such as cysteine ​​provide disulfide crosslinking sites. The outer dense polyacrylate film controls the release rate.

[0040] This microcapsule formulation, containing three core active ingredients—diethylhexyl maleate, keratin amino acids, and hydrolyzed keratin—is delivered specifically to damaged areas of the hair cortex. The outer layer of the capsule wall swells in an alkaline environment (such as during perming and dyeing), releasing the core material to the disulfide bond breakage sites. The -SH group of cysteine ​​binds to the broken -SH groups in the hair, rebuilding the -SS- network. This targeted repair of broken disulfide bonds during perming and dyeing reverses keratin damage and restores damaged hair quality.

[0041] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0042] (1) The keratin-bonded microcapsule agent prepared by the present invention can be used as an additive in hair products. It has good formula compatibility and can be targeted to the damaged area of ​​the hair cortex to repair the disulfide bonds broken during the perming and dyeing process, reverse keratin damage, repair damaged hair quality, improve hair breaking strength, and reduce hair breakage.

[0043] (2) The capsule wall of the microcapsule of the present invention has a double-layer structure: the inner layer is a three-dimensional network formed by the self-assembly of hydrolyzed keratin, keratin amino acids and hydrophilic polymer interfaces; the outer layer is a dense polymer film formed by copolymerization of acrylate monomers and crosslinking agents. The outer layer of the capsule wall swells in an alkaline environment, releasing the core material to the disulfide bond breaking site, thereby achieving the effect of pH-responsive control of the release rate.

[0044] (3) The core of the microcapsule of the present invention contains three active ingredients: diethylhexyl maleate, keratin amino acids, and hydrolyzed keratin, which serve as a keratin rebuilding complex. The three components achieve fundamental reversal of damage through spatial hierarchical repair and synergistically repair damaged hair. Detailed Implementation

[0045] To better illustrate the purpose, technical solution, and beneficial effects of this invention, the technical solution of this invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention. In specific embodiments, unless otherwise specified, the experimental methods used are conventional experimental methods, and the materials and reagents used are commercially available. All parts are expressed in parts by weight.

[0046] Example 1

[0047] This embodiment provides a keratin-bonded microcapsule agent comprising the following components in parts by weight:

[0048] 25 parts of diethylhexyl maleate;

[0049] Cysteine ​​15 parts;

[0050] Eight portions of hydrolyzed keratin, wherein the hydrolyzed keratin has a molecular weight of 3500 Da;

[0051] 40 parts of isopropyl myristate;

[0052] Three parts of polyethylene glycol, wherein the polyethylene glycol has a molecular weight of 6000 Da;

[0053] 7 parts butyl acrylate;

[0054] 1 part of N,N'-methylenebisacrylamide;

[0055] 0.8 parts potassium persulfate;

[0056] 1.5 parts CaCl2;

[0057] 8 parts polyvinyl alcohol;

[0058] 1 part sodium alginate;

[0059] 100 parts deionized water;

[0060] The method for preparing the keratin-bonded microcapsule agent includes the following steps:

[0061] (1) Preparation of oil phase: Diethylhexyl maleate, cysteine, hydrolyzed keratin and isopropyl myristate are mixed and dissolved at 60°C to obtain oil phase;

[0062] (2) Preparation of aqueous phase: Polyvinyl alcohol and sodium alginate were dissolved in deionized water, and the pH was adjusted to 5.0 with 10% citric acid solution to obtain the aqueous phase;

[0063] (3) Emulsification: The oil phase is injected into the aqueous phase and homogenized at 10,000 rpm for 3 minutes to obtain an emulsion;

[0064] (4) Interface self-assembly: Add polyethylene glycol to the emulsion and stir at 60°C for 1.5 hours;

[0065] (5) Polymerization and curing: Add butyl acrylate, N,N'-methylenebisacrylamide and potassium persulfate to the emulsion and react at 60°C for 2 hours;

[0066] (6) Post-curing: Add CaCl2 to the emulsion, stir at 25°C for 1 hour, collect the microcapsules by centrifugation, and obtain the microcapsule agent by spray drying.

[0067] Example 2

[0068] This embodiment provides a keratin-bonded microcapsule agent comprising the following components in parts by weight:

[0069] 30 parts of diethylhexyl maleate;

[0070] 25 parts of N-acetylcysteine;

[0071] 10 parts of hydrolyzed keratin, wherein the hydrolyzed keratin has a molecular weight of 2000 Da;

[0072] Caprylic / capric triglyceride 50 parts;

[0073] Five parts of polyethylene glycol, wherein the polyethylene glycol has a molecular weight of 10,000 Da;

[0074] 10 parts of methyl methacrylate;

[0075] 2 parts of N,N'-methylenebisacrylamide;

[0076] 1 part ammonium persulfate;

[0077] 2 parts aluminum sulfate;

[0078] 10 portions of Polosham;

[0079] 1.5 parts carboxymethyl cellulose;

[0080] 120 parts deionized water;

[0081] The method for preparing the keratin-bonded microcapsule agent includes the following steps:

[0082] (1) Preparation of oil phase: Diethylhexyl maleate, N-acetylcysteine, hydrolyzed keratin, and caprylic / capric triglyceride were mixed and dissolved at 70°C to obtain the oil phase;

[0083] (2) Preparation of aqueous phase: Poloxamer and carboxymethyl cellulose were dissolved in deionized water, and the pH was adjusted to 6.0 with 10% citric acid solution to obtain the aqueous phase;

[0084] (3) Emulsification: The oil phase is injected into the aqueous phase and homogenized at 12,000 rpm for 5 minutes to obtain an emulsion;

[0085] (4) Interface self-assembly: Add polyethylene glycol to the emulsion and stir at 65°C for 2 hours;

[0086] (5) Polymerization and curing: Methyl methacrylate, N,N'-methylenebisacrylamide and ammonium persulfate were added to the emulsion and reacted at 65°C for 3 hours;

[0087] (6) Post-curing: Add aluminum sulfate to the emulsion, stir at 30°C for 2 hours, collect the microcapsules by centrifugation, and obtain the microcapsule agent by spray drying.

[0088] Example 3

[0089] This embodiment provides a keratin-bonded microcapsule agent comprising the following components in parts by weight:

[0090] 15 parts of diethylhexyl maleate;

[0091] 10 parts of cysteine ​​hydrochloride;

[0092] Five portions of hydrolyzed keratin, wherein the hydrolyzed keratin has a molecular weight of 5000 Da;

[0093] 25 parts of isopropyl myristate;

[0094] Two parts of polyethylene glycol, wherein the polyethylene glycol has a molecular weight of 4000 Da;

[0095] 5 parts butyl acrylate;

[0096] 0.5 parts of N,N'-methylenebisacrylamide;

[0097] 0.5 parts potassium persulfate;

[0098] CaCl2 1 part;

[0099] 5 parts sodium dodecyl sulfate;

[0100] 0.5 parts sodium alginate;

[0101] 60 parts deionized water;

[0102] The method for preparing the keratin-bonded microcapsule agent includes the following steps:

[0103] (1) Preparation of oil phase: Diethylhexyl maleate, cysteine ​​hydrochloride, hydrolyzed keratin and isopropyl myristate are mixed and dissolved at 50°C to obtain oil phase;

[0104] (2) Preparation of aqueous phase: Sodium dodecyl sulfate and sodium alginate were dissolved in deionized water, and the pH was adjusted to 4.0 with 10% citric acid solution to obtain the aqueous phase;

[0105] (3) Emulsification: The oil phase is injected into the aqueous phase and homogenized at 8000 rpm for 2 minutes to obtain an emulsion;

[0106] (4) Interface self-assembly: Add polyethylene glycol to the emulsion and stir at 55°C for 1 hour;

[0107] (5) Polymerization and curing: Add butyl acrylate, N,N'-methylenebisacrylamide and potassium persulfate to the emulsion and react at 55°C for 1 hour;

[0108] (6) Post-curing: Add CaCl2 to the emulsion, stir at 20°C for 1 hour, collect the microcapsules by centrifugation, and obtain the microcapsule agent by spray drying.

[0109] Comparative Example 1

[0110] This comparative example provides a keratin-bonded microcapsule, which differs from Example 1 in that it does not contain diethylhexyl maleate, but is replaced by isopropyl myristate.

[0111] Comparative Example 2

[0112] This comparative example provides a keratin-bonded microcapsule, which differs from Example 1 in that it does not contain cysteine, and its dosage is replaced by isopropyl myristate.

[0113] Comparative Example 3

[0114] This comparative example provides a keratin-bonded microcapsule, which differs from Example 1 in that it does not contain hydrolyzed keratin and is replaced by isopropyl myristate.

[0115] Comparative Example 4

[0116] This comparative example provides a keratin-bonded microcapsule agent, which differs from Example 1 in that step (4) interface self-assembly is omitted.

[0117] Comparative Example 5

[0118] This comparative example provides a keratin-bonded microcapsule agent, which differs from Example 1 in that step (5) polymerization and curing is omitted.

[0119] Test Example 1: Microcapsule Particle Size Test

[0120] I. Testing Methods

[0121] Following the preparation methods in Examples 1-3 and Comparative Examples 1-5, keratin-bonded microcapsules were prepared for each group. The prepared microcapsules were dispersed in deionized water to form a uniform suspension. The particle size distribution of the microcapsules was measured using a laser particle size analyzer. The initial average particle size, and the average particle size after 1 month and 3 months of sealed storage under room temperature, light-proof, and dry conditions were measured. Each sample was measured three times, and the average value was taken as the final result.

[0122] II. Experimental Results

[0123] Table 1

[0124]

[0125]

[0126] The keratin-bonded microcapsules of Examples 1-3 of this invention, possessing a complete bilayer capsule wall structure (an inner three-dimensional network and an outer dense polymer film), exhibit significantly better storage stability than the comparative examples. The initial average particle size of Examples 1-3 was 234.5-259.1 nm, increasing by 10-20 nm after one month of storage and by 20-40 nm after three months, with the particle size controlled within 300 nm. The narrow particle size distribution and minimal variation meet the requirements for targeted delivery. Comparative Examples 1-3, lacking any active component from diethylhexyl maleate, keratin amino acids, or hydrolyzed keratin, showed decreased compatibility between the capsule core and capsule wall, increasing by 30-50 nm after one month and reaching 60-90 nm after three months. Comparative Examples 4-5, omitting key preparation steps such as interface self-assembly or polymerization curing, had incomplete capsule wall structures, increasing by 40-60 nm after one month and 70-90 nm after three months, exhibiting poor stability. The results show that the synergistic effect of the three active ingredients in the formulation of this invention and the double-layer capsule wall preparation process are the key to ensuring the long-term storage stability of microcapsules, and provide a reliable basis for their application in the formula.

[0127] Test Example 2: Hair Mechanical Property Repair Test

[0128] I. Testing Methods

[0129] 1. Hair bundle preparation

[0130] Hair source: Select hair from healthy women aged 20–30, with a length of 15cm.

[0131] Pretreatment: Bleaching was performed using a 6% hydrogen peroxide solution to simulate damage from perming and dyeing. The specific steps were as follows: the hair sample was immersed in the 6% hydrogen peroxide solution; treated at 25°C for 30 minutes; the hair was thoroughly rinsed with deionized water to remove any residual hydrogen peroxide solution; and the treated hair was conditioned at 21°C and 65% RH for 4 hours.

[0132] Grouping: The hair was randomly divided into 11 groups (Examples 1–3, Comparative Examples 1–5, Blank Damage Group, Silicone Conditioner Control Group, and Healthy Control Group), with 10 hairs in each group.

[0133] deal with:

[0134] Examples 1–3 and Comparative Examples 1–5: 2g of the microcapsule to be tested was dispersed in 100mL of deionized water (pH 9.2, simulating the alkaline environment of hair perming / dyeing). The hair was soaked at 25°C for 20min, then dried with hot air at 45°C, and then humidified at 21°C and 65%RH for 4h.

[0135] Silicone oil conditioner control group: Hair was immersed in commercially available silicone oil conditioner (concentration 2g / 100mL deionized water) at 25℃ for 20min, then dried with hot air at 45℃, and then humidified at 21℃ and 65% RH for 4h.

[0136] Healthy control group: Healthy hair that has not undergone any pretreatment or repair treatment was directly subjected to mechanical performance testing.

[0137] Blank damaged group: only pretreated (bleached with 6% hydrogen peroxide solution for 30 min), without any repair treatment.

[0138] 2. Instruments and Parameters

[0139] Constant rate elongation (CRE) tensile tester, gauge length 20 mm, stretching speed 10 mm / min, temperature 21℃, humidity 65% ​​RH.

[0140] Test parameters: breaking strength (cN), elongation at break (%).

[0141] 3. Data Acquisition

[0142] Ten hairs were tested in each group, and outliers with significant deviations were removed. The average value was taken as the final result.

[0143] 4. Formula for calculating repair rate

[0144]

[0145] Strong repair rate (%):

[0146] in:

[0147] F treat Breaking strength (cN) of treated hair.

[0148] F damage Breaking strength (cN) of hair in the blank damaged group

[0149] F healthy Breaking strength (cN) of hair from the healthy control group.

[0150] Elongation recovery rate (%):

[0151] in:

[0152]

[0153] ε treat Breakage elongation of treated hair (%)

[0154] ε damage Breakage elongation rate (%) of hair in the blank damaged group

[0155] ε healthy Breakage elongation rate (%) of hair in the healthy control group.

[0156] II. Experimental Results

[0157] Table 2

[0158] Group Breaking Strength (cN) Strength Repair Rate (%) Elongation at Break (%) Elongation Repair Rate (%) Healthy Control 255.3 — 36.2 — Blank Damage 140.7 — 22.1 — Example 1 218.5 67.9 31.8 68.8 Example 2 213.2 63.3 30.9 62.4 Example 3 208.9 59.5 30.2 57.4 Comparative Example 1 175.4 30.3 25.3 22.7 Comparative Example 2 172.3 27.6 24.7 18.4 Comparative Example 3 169.1 24.8 24.2 14.9 Comparative Example 4 178.1 32.6 25.8 26.2 Comparative Example 5 173.5 28.6 24.9 19.9 Silicone Conditioner Control 184.7 38.4 28.5 45.4

[0159] Example 1 showed a break strength repair rate of 67.9% and a break elongation repair rate of 68.8%, significantly higher than other examples and the control group, indicating that it had the best repair effect on damaged hair. The repair effects of Examples 1-3 were relatively close to the mechanical properties of healthy hair, demonstrating that their formulation and process can effectively reverse hair damage.

[0160] In contrast, omitting any of the active components from diethylhexyl maleate (Comparative Example 1), keratin amino acids (Comparative Example 2), or hydrolyzed keratin (Comparative Example 3) resulted in strong repair rates of only 30.3%, 27.6%, and 24.8%, respectively, significantly lower than the 67.9% in Example 1, indicating a significant synergistic effect among the three. Diethylhexyl maleate provides carboxyl groups to bond with keratin amino groups, crosslinking broken chains. Keratin amino acids (thiol amino acids) replenish -SH in situ, rebuilding disulfide bonds. Hydrolyzed keratin rapidly fills cracks and induces β-sheets, improving hair resilience. These three active ingredients—diethylhexyl maleate, keratin amino acids, and hydrolyzed keratin—act as a keratin rebuilding complex, achieving fundamental reversal of damage through spatial hierarchical repair, and synergistically repairing damaged hair.

[0161] Furthermore, omitting the interface self-assembly (Comparative Example 4) or polymerization curing (Comparative Example 5) caused premature disintegration of the microcapsules in an alkaline environment, preventing the active ingredients from being targeted and delivered to the hair cortex, resulting in a decreased repair rate. The double-layered capsule structure of Example 1 ensured stable release and highly targeted delivery of the active ingredients. The commercially available silicone oil conditioner control group showed a strong repair rate of only 38.4% and an elongation repair rate of 45.4%, which were also lower than the repair effect of Example 1, indicating that silicone oil conditioners can only provide surface lubrication and cannot deeply repair damaged hair.

[0162] The keratin-bonded microcapsule agent of this invention can significantly restore the mechanical properties of damaged hair. The key to achieving a high repair rate lies in the three active ingredients—diethylhexyl maleate, keratin amino acids, and hydrolyzed keratin—along with the double-layer capsule wall design, resulting in a significant repair effect. In contrast, silicone-based conditioners only provide surface lubrication and cannot deeply repair damaged hair.

[0163] Test Example 3: Split End Reduction Performance Test

[0164] I. Testing Methods

[0165] 1. Hair bundle preparation

[0166] Hair source: Hair from healthy women aged 20–30, 15cm in length.

[0167] Pretreatment: Bleaching was performed using a 6% hydrogen peroxide solution to simulate damage from perming and dyeing. The specific steps were as follows: the hair sample was immersed in the 6% hydrogen peroxide solution; treated at 25°C for 30 minutes; the hair was thoroughly rinsed with deionized water to remove any residual hydrogen peroxide solution; and the treated hair was conditioned at 21°C and 65% RH for 4 hours.

[0168] 2. Grouping

[0169] Healthy control group: Healthy hair that has not undergone any pretreatment or repair treatment was tested directly.

[0170] Blank damaged group: only pretreated (bleached with 6% hydrogen peroxide solution for 30 min), without any repair treatment.

[0171] Examples 1-3: After pretreatment, the microencapsulation agents of Examples 1-3 of the present invention were used for treatment.

[0172] Comparative Examples 1-5: After pretreatment, the microencapsulation agents of Comparative Examples 1-5 were used.

[0173] Silicone oil conditioner control group: After pretreatment, commercially available silicone oil conditioner was used.

[0174] 3. Handling methods

[0175] Examples 1-3 and Comparative Examples 1-5: 2g of the microcapsule to be tested was dispersed in 100mL of deionized water (pH 9.2, simulating the alkaline environment of perming / dyeing hair), and the hair was soaked at 25°C for 20min. After being removed, the hair was dried with hot air at 45°C and then humidified at 21°C and 65%RH for 4h.

[0176] Silicone oil conditioner control group: Hair was immersed in commercially available silicone oil conditioner (concentration 2g / 100mL deionized water) at 25℃ for 20min, then dried with hot air at 45℃, and then humidified at 21℃ and 65% RH for 4h.

[0177] 4. Testing Methods

[0178] Hair breakage test: The treated hair sample was fixed and combed using a standard combing device. The number of hairs broken during the combing process was recorded. 30 hairs were used as a single bundle for the test, with each bundle repeated 3 times. The average value was taken as the final result.

[0179] II. Experimental Results

[0180] Table 3

[0181] Group Average Number of Split Ends (Roots) Split End Reduction Rate (%) Healthy Control 2.1 — Blank Damage 10.2 — Example 1 3.2 68.6 Example 2 3.7 63.7 Example 3 4.1 59.8 Comparative Example 1 7.3 28.4 Comparative Example 2 7.8 23.5 Comparative Example 3 8.2 19.6 Comparative Example 4 6.2 39.2 Comparative Example 5 6.6 35.3 Silicone Conditioner Control 5.1 50

[0182] Formula for calculating hair loss reduction rate

[0183]

[0184] Example 1 showed a hair breakage reduction rate of 68.6%, significantly higher than other examples and the control group, indicating that it was the most effective in reducing hair breakage. Examples 2-3 showed slightly lower hair breakage reduction rates than Example 1. The hair breakage reduction rates of Examples 1-3, along with the experimental results of hair mechanical property testing in Example 1, all demonstrate that the protein-bonded microcapsule agent of this invention has a significant repair effect on hair.

[0185] In contrast, the breakage reduction rates of Comparative Examples 1-3 were 28.4%, 23.5%, and 19.6%, respectively, significantly lower than those of Examples 1-3. This indicates that omitting any of the active components from diethylhexyl maleate (Comparative Example 1), keratin amino acids (Comparative Example 2), or hydrolyzed keratin (Comparative Example 3) significantly reduced the repair effect and increased breakage. The breakage reduction rates of Comparative Examples 4-5 were 39.2% and 35.3%, respectively, slightly higher than those of Comparative Examples 1-3, but still lower than those of Examples 1-3, indicating that the double-layered capsule structure has a significant impact on the repair effect. The breakage reduction rate of the silicone oil conditioner control group was 50.0%, with an effect between that of Examples 1-3 and Comparative Examples 1-5, indicating that silicone oil conditioner can only provide surface lubrication and cannot deeply repair damaged hair.

[0186] The protein-bonded microcapsule agent of this invention showed a significant effect in reducing hair breakage. Similar to the experimental results of the hair mechanical property test in Test Example 1, both showed a significant repair effect, indicating that the protein-bonded microcapsule agent of this invention has a significant effect in reducing hair breakage and repairing hair mechanical properties.

[0187] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A keratin-bonding microcapsule agent, characterized in that, Includes the following components in parts by weight: 15-30 parts of diethylhexyl maleate; 10-25 parts of keratin amino acids; 5-10 parts hydrolyzed keratin; 25-50 parts of carrier solvent; 2-5 parts of hydrophilic polymer; 5-10 parts of acrylate monomer; Crosslinking agent 0.5-2 parts; Initiator 0.5-1 part; 1-2 parts of curing agent; 5-10 parts emulsifier; Stabilizer 0.5-1.5 parts; 60-120 parts deionized water; The hydrophilic polymer is polyethylene glycol with a molecular weight of 4000-10000 Da; The keratin amino acids are thiol-containing amino acids; the thiol-containing amino acids are selected from one or more of cysteine, N-acetylcysteine, and cysteine ​​hydrochloride. The molecular weight of the hydrolyzed keratin is 2000-5000 Da; The preparation method of the microcapsule includes the following steps: (1) Preparation of oil phase: Diethylhexyl maleate, keratin amino acids, hydrolyzed keratin, and carrier solvent are mixed and dissolved at 50-70℃ to obtain oil phase; (2) Preparation of aqueous phase: Dissolve emulsifier and stabilizer in deionized water, and adjust pH to 4.0-6.0 with 10% citric acid solution to obtain aqueous phase; (3) Emulsification: The oil phase is injected into the aqueous phase and homogenized at 8000-12000 rpm for 2-5 minutes to obtain an emulsion; (4) Interface self-assembly: Add hydrophilic polymer to the emulsion and stir at 55-65℃ for 1-2 hours; (5) Polymerization and curing: Add acrylate monomers, crosslinking agents and initiators to the emulsion and react at 55-65℃ for 1-3 hours; (6) Post-curing: Add curing agent to emulsion, stir at 20-30℃ for 1-2 hours, collect microcapsules by centrifugation, and obtain microcapsule agent by spray drying.

2. The microencapsulation agent as described in claim 1, characterized in that: The carrier solvent is selected from isopropyl myristate and / or caprylic / capric triglyceride.

3. The microencapsulation agent as described in claim 1, characterized in that: The acrylate monomer is butyl acrylate or methyl methacrylate; the crosslinking agent is N,N'-methylenebisacrylamide.

4. The microencapsulation agent as described in claim 1, characterized in that: The emulsifier is selected from polyvinyl alcohol, poloxamer, or sodium dodecyl sulfate; the stabilizer is selected from sodium alginate or carboxymethyl cellulose; the initiator is ammonium persulfate or potassium persulfate; and the curing agent is CaCl2 or aluminum sulfate.

5. The application of a keratin-bonded microcapsule agent in the preparation of hair composition, characterized in that, The keratin-bonded microcapsule is the microcapsule as described in any one of claims 1-4.

6. A hair-applied composition, characterized in that, The composition comprises 0.5-5 wt% of a keratin-bonded microcapsule agent, wherein the keratin-bonded microcapsule agent is the microcapsule agent according to any one of claims 1-4, and the pH of the composition is 7.0-10.

0.

7. The hair-applied composition as claimed in claim 6, characterized in that: The hair composition includes any one of a perming agent, a hair dye, or a hair care product.

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