PH-responsive mould-targeted controlled-release essence microcapsule for daily use and preparation method thereof

Abstract

The invention relates to the technical field of controlled-release microcapsules, and particularly discloses a pH-responsive mold-targeted controlled-release essence microcapsule for daily chemicals and a preparation method thereof.The preparation method comprises the following steps that S1, chitosan is dissolved with an acid solution, a catalyst and a pH sensitive reagent are added under the protective atmosphere for a reaction, and a pH-responsive graft copolymerization product is obtained through separation and purification; s2, mixing the pH response graft copolymerization product, a cross-linking agent and a mould targeting reagent for reaction, and dialyzing and purifying to obtain a microcapsule wall material; and S3, emulsifying essence by using an emulsifier, and then adding a defoaming agent, the microcapsule wall material, the sodium tripolyphosphate aqueous solution and a pH regulator to prepare the pH-responsive mold-targeted controlled-release essence microcapsule for daily use. The microcapsule integrates specific recognition targeting ability and pH response release ability to mould, and can accurately release natural essence with bacteriostatic and aromatic functions at the mould breeding part of clothes, so that the dual effects of bacteriostasis and aroma retention are realized.

Description

Technical Field

[0001] This invention relates to the field of controlled-release microcapsule technology, specifically to a pH-responsive mold-targeted controlled-release fragrance microcapsule for daily chemical use and its preparation method. Background Technology

[0002] Textiles, especially natural fiber products such as cotton and linen, are highly susceptible to mold growth during storage and wear (particularly in humid environments). Mold proliferation not only leads to stubborn mildew stains and fiber degradation and brittleness, but also produces unpleasant odors and may even cause skin allergies. The conventional method for giving textiles anti-mold properties is to directly apply anti-mold agents (such as isothiazolinones and organosilicon quaternary ammonium salts) to the fabric through padding or spraying. This method has significant drawbacks: 1) The anti-mold agent does not bond firmly to the fabric and is easily washed away during washing or friction, resulting in short-lived anti-mold functionality; 2) The anti-mold agent is released slowly and non-selectively across the entire fabric surface, resulting in low utilization and potential unnecessary interference with the skin's microenvironment (such as normal flora); 3) It cannot achieve high concentrations and rapid action in the initial "hotspots" of mold growth, resulting in poor prevention and control effects.

[0003] Natural plant extracts (such as eugenol, cinnamaldehyde, and anethole) possess both natural antibacterial and aromatic properties, but their direct application to textiles faces bottlenecks such as volatility, poor washability, and uncontrollable release. Fragrance microcapsules are a micron-encapsulation technology that uses natural or synthetic polymer shells to encapsulate functional core materials such as fragrances and essential oils. This technology makes the core material less volatile, washable, and provides controlled release. Developing a fragrance microcapsule that intelligently responds to the acidic microenvironment of mold and targets its release is of great significance for improving the anti-mold efficiency of daily chemical products, extending their shelf life, and enhancing their environmental friendliness. Summary of the Invention

[0004] To address the aforementioned issues, this invention provides a pH-responsive mold-targeting controlled-release fragrance microcapsule for daily chemical use and its preparation method, which has advantages such as biological targeting, intelligent release, natural antibacterial properties, and long-lasting fragrance.

[0005] This invention provides a method for preparing pH-responsive mold-targeted controlled-release fragrance microcapsules for daily chemical use, comprising the following steps: S1. Dissolve chitosan in an acidic solution, add a catalyst and pH-sensitive reagent under a protective atmosphere to react, and separate and purify to obtain the pH-responsive graft copolymer. S2. The pH-responsive graft copolymer, crosslinking agent and mold-targeting reagent are mixed and reacted, and the microcapsule wall material is obtained after dialysis purification. S3. The fragrance is emulsified with an emulsifier, and then an antifoaming agent, microcapsule wall material, sodium tripolyphosphate aqueous solution and pH adjuster are added to prepare pH-responsive mold-targeted controlled-release fragrance microcapsules for daily chemical use.

[0006] Optionally, the acidic solution in S1 is one of hydrochloric acid, citric acid, acetic acid, sulfuric acid, carbonic acid, and lactic acid with a mass concentration of 1-20%; the catalyst is one of hydrogen peroxide, sodium peroxide, peracetic acid, potassium peroxide, calcium peroxide, ammonium persulfate, potassium persulfate, and sodium persulfate; and the pH-sensitive reagent is one of acrylic acid, glyoxylic acid, chloroalkyl acid, phenylboronic acid, and 4-vinylpyridine.

[0007] Optionally, the mass ratio of chitosan to pH-sensitive reagent is 1:0.1~7.

[0008] Optionally, the reaction temperature in S1 is 40℃~100℃, the reaction time is 0.5h~8h, and the reaction is separated and purified by one or more of the following methods: filtration, recrystallization, dialysis, column chromatography and extraction.

[0009] Optionally, the crosslinking agent in S2 is one or more of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride, bis(succinimide) octanoate, dithiosuccinimide propionate, maleimide acetate succinimide ester, pentafluorophenol biotin ester, glutarate succinimide ester, and N-hydroxysuccinimide; the mold targeting agent is one of wheat germ lectin, 1,8-dihydroxynaphthalene melanin, C-type lectin, biphenyl, o-phenylphenol, and 2-pyridinium thiol-1-zinc oxide.

[0010] Optionally, the mass ratio of pH-responsive graft copolymer, crosslinking agent and mold-targeting reagent in S2 is 1:0.01~1:0.2~4.

[0011] Optionally, the mixing temperature of the pH-responsive graft copolymer and the mold-targeting reagent in S2 is below 4°C, and the mixing time is 12-24h. Optionally, the emulsifier in S3 is one or more of sodium stearate, sodium dodecyl sulfate, calcium dodecylbenzene sulfonate, Tween, gum arabic, styrene-maleic anhydride copolymer, polyoxyethylene ether, polyoxypropylene ether, polyvinyl alcohol, and lecithin; the defoamer is one or more of sodium stearate, stearamide, potassium tartrate, magnesium silicate, and calcium silicate; and the pH adjuster is one or more of calcium hydroxide, potassium hydroxide, sodium hydroxide, fumaric acid, metatartaric acid, adipic acid, and hydrochloric acid.

[0012] Optionally, the flavoring is one or more of the following: orange peel flavoring, mugwort flavoring, clove flavoring, eucommia flavoring, cinnamon flavoring, astragalus flavoring, and bamboo leaf flavoring; This invention also relates to pH-responsive mold-targeted controlled-release fragrance microcapsules for daily chemical use obtained by the aforementioned preparation method.

[0013] Because mold cell walls are rich in specific receptors such as chitin and N-acetylglucosamine, wheat germ agglutinin (WGA) can specifically recognize and bind to these receptors, exhibiting excellent mold targeting. It forms localized high-concentration aggregations in mold-affected areas, inhibiting spore germination and hyphal growth. Furthermore, molds secrete organic acids (such as citric acid and oxalic acid) during metabolism, causing a significant drop in the pH of the microenvironment surrounding their colonies to 4.0-5.5, while the pH of fabrics under normal storage conditions is close to neutral. This difference provides a perfect target for designing an intelligent anti-mold system: that is, the system remains dormant in the absence of mold metabolites, only activating a pH-responsive release mechanism in the localized acidic environment caused by mold activity, thus inhibiting mold growth and reproduction.

[0014] The present invention has the following beneficial effects: This invention modifies chitosan (CS). Free radicals generated by the thermal decomposition of a peroxide catalyst abstract H atoms from the CH or NH bonds of sugar residues on the chitosan molecular chain, producing chitosan macromolecular free radicals. These radicals further initiate the polymerization of acrylic acid monomers, forming polyacrylic acid branches, ultimately resulting in a branched copolymer of polyacrylic acid chitosan. This copolymer exhibits pH responsiveness. The chitosan backbone is dense under neutral conditions. In the acidic microenvironment induced by mold (pH 4.0–5.5), the amino groups on the chitosan molecular chain protonate (-NH2 → -NH3+), leading to increased intermolecular repulsion, network swelling, and partial breakage of ionic crosslinks, thereby achieving rapid release of the fragrance. Furthermore, this invention grafts WGA onto the polyacrylic acid chitosan. WGA specifically recognizes and binds to glycoproteins on the surface of mold cell walls, exhibiting biotargeting properties, allowing microcapsules to accumulate around mold colonies for precise release.

[0015] The chitosan and wheat germ lectin used in this invention, along with the plant fragrance used as the core material, are all derived from natural sources, exhibiting good biocompatibility and avoiding the safety hazards associated with synthetic chemicals. The fragrance acts as both an aromatizer and an antibacterial agent, offering dual benefits and solving the challenge of simultaneously preventing mold and retaining fragrance. The prepared fragrance microcapsules have robust walls, providing long-lasting fragrance retention under normal conditions; while in moldy environments, they achieve precise release, directly killing mold, with a long-lasting effect and resistance to water washing. Attached Figure Description

[0016] Figure 1 The particle size distribution diagrams are for Examples 1, 2, 4 and Comparative Example 2. Detailed Implementation

[0017] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials used in the following examples are commercially available products.

[0018] A method for preparing pH-responsive mold-targeted controlled-release fragrance microcapsules for daily chemical use includes the following steps: S1. Chitosan is dissolved in an acidic solution, and a catalyst and pH-sensitive reagent are added under a protective atmosphere to react and separate and purify the pH-responsive graft copolymer. The acidic solution is preferably one of hydrochloric acid, citric acid, acetic acid, sulfuric acid, carbonic acid, and lactic acid with a mass concentration of 1-20%. The catalyst is preferably one of hydrogen peroxide, sodium peroxide, peracetic acid, potassium peroxide, calcium peroxide, ammonium persulfate, potassium persulfate, and sodium persulfate. The pH-sensitive reagent is one of acrylic acid, glyoxylic acid, chloroalkyl acid, phenylboronic acid, and 4-vinylpyridine; preferably acrylic acid. The reaction temperature is 40℃~100℃, and the reaction time is 0.5h~8h; more preferably, the reaction temperature is 60℃, and the reaction time is 3h. After the reaction, separation and purification are performed by one or more of filtration, recrystallization, dialysis, column chromatography, and extraction.

[0019] S2. The pH-responsive graft copolymer, crosslinking agent, and mold-targeting reagent are mixed and reacted, and the mixture is purified by dialysis to obtain the microcapsule wall material. The crosslinking agent is one or more of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride, bis(succinimide) octanoate, dithiosuccinimide propionate, maleimide acetate succinimide ester, pentafluorophenol biotin ester, glutarate succinimide ester, and N-hydroxysuccinimide. The mold-targeting reagent is one of wheat germ lectin, 1,8-dihydroxynaphthalene melanin, C-type lectin, biphenyl, o-phenylphenol, and 2-pyridinethiol-1-zinc oxide. The mixing temperature of the pH-responsive graft copolymer and the mold-targeting reagent is below 4°C, and the mixing time is 12-24 h. Preferably, the mass ratio of the pH-responsive graft copolymer, crosslinking agent, and mold-targeting reagent in S2 is 1:0.01~1:0.2~4.

[0020] S3. Emulsify the fragrance with an emulsifier, then add an antifoaming agent, microcapsule wall material, sodium tripolyphosphate aqueous solution, and pH adjuster to prepare pH-responsive mold-targeted controlled-release fragrance microcapsules for daily chemical use; the emulsifier is one or more of sodium stearate, sodium dodecyl sulfate, calcium dodecylbenzene sulfonate, Tween, gum arabic, styrene-maleic anhydride copolymer, polyoxyethylene ether, polyoxypropylene ether, polyvinyl alcohol, and lecithin; the antifoaming agent is one or more of sodium stearate, stearamide, potassium tartrate, magnesium silicate, and calcium silicate; the pH adjuster is one or more of calcium hydroxide, potassium hydroxide, sodium hydroxide, fumaric acid, metatartaric acid, adipic acid, and hydrochloric acid; the fragrance is one or more of orange peel fragrance, artemisia fragrance, clove fragrance, eucommia fragrance, cinnamon fragrance, astragalus fragrance, and bamboo leaf fragrance.

[0021] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are only for illustrating the present invention and should not be regarded as limiting the scope of the present invention.

[0022] Example 1 A method for preparing pH-responsive mold-targeted controlled-release microcapsules for daily chemical use, comprising the following steps: Preparation of S1 polyacrylic acid chitosan: Weigh 5.0 g of chitosan (degree of deacetylation ≥ 90%) and dissolve it in 10% glacial acetic acid. Disperse the solution into a clear solution at 50℃ and 500 rpm. Purge with nitrogen to remove oxygen for 15 min, add 0.1 g APS and 4 mL acrylic acid, and react at 60℃ for 3 h. After the reaction is complete, put the mixed solution into a dialysis bag and dialyze it in flowing pure water for 48 h to remove unreacted small molecules and monomers, finally obtaining polyacrylic acid chitosan.

[0023] Preparation of S2 CS-WGA grafted product: 5g of polyacrylic acid chitosan prepared in S1 was dissolved in 15% glacial acetic acid, and 0.15g of NHS was added. The mixture was stirred at room temperature for 30 min. Subsequently, 10g of WGA in PBS solution (pH=7.4) was added dropwise, and the mixture was slowly stirred at 4℃ for 24 h to allow the amino groups of WGA to undergo amidation with the activated carboxyl groups of chitosan, forming a conjugate. The reaction solution was dialyzed and freeze-dried to obtain CS-WGA grafted product powder.

[0024] Preparation of S3 oil phase: Dissolve 20g of clove essential oil in 100g of corn oil and stir evenly at 300rpm at room temperature to prepare clove essence with a mass concentration of 20%.

[0025] Preparation of S4 aqueous phase (wall material): Dissolve 1g of CS-WGA graft product powder prepared in S2 in 100g of dilute acetic acid aqueous solution (1% v / v) to prepare a 1% aqueous phase solution, which is used as the wall material.

[0026] S5 emulsion preparation: Under high-speed shear at 3000 rpm, 80 g of oil phase (S3) was slowly added to 120 g of 5% Tween 80 for emulsification for 5 min. Then, 0.1% (w / w) of calcium silicate for fragrance was added, followed by 5 g of aqueous phase (S4). After uniform dispersion, 2 g of sodium tripolyphosphate aqueous solution (10%) was added dropwise. The mixture was stirred at 500 rpm for 2 h. Then, 25% sodium hydroxide was added, and the mixture was stirred at 500 rpm for 2 h. After the encapsulation was completed, a stable O / W type emulsion was formed with a particle size of 14.53 μm, which yielded the pH-responsive mold-targeted controlled-release clove fragrance microcapsule emulsion for daily chemical use.

[0027] Example 2 A method for preparing pH-responsive mold-targeted controlled-release microcapsules for daily chemical use, comprising the following steps: Preparation of S1 polyacrylic acid chitosan: Weigh 10.0 g of chitosan (degree of deacetylation ≥ 90%) and dissolve it in 10% glacial acetic acid solution. Disperse the solution into a clear solution at 50℃ and 600 rpm. Purge nitrogen to remove oxygen for 15 min, add 0.2 g APS and 4 mL acrylic acid, and react at 60℃ for 3 h. After the reaction is complete, put the mixed solution into a dialysis bag and dialyze it in flowing pure water for 48 h to remove unreacted small molecules and monomers, finally obtaining polyacrylic acid chitosan.

[0028] Preparation of S2 CS-WGA grafted product: 6g of the polyacrylic acid chitosan product prepared in S1 was dissolved in a 15% glacial acetic acid solution, and 0.18g of NHS was added. The mixture was stirred at room temperature for 30 min. Subsequently, 12g of WGA in PBS solution (pH=7.4) was added dropwise, and the mixture was slowly stirred at 4℃ for 24 h to allow the amino groups of WGA to undergo an amidation reaction with the activated carboxyl groups of chitosan, forming a conjugate. The reaction solution was dialyzed and freeze-dried to obtain CS-WGA grafted product powder.

[0029] Preparation of S3 oil phase: Dissolve 10g of Artemisia argyi essential oil in 100g of corn oil and stir evenly at 200rpm at room temperature to prepare Artemisia argyi fragrance with a mass concentration of 10%.

[0030] Preparation of S4 aqueous phase: Dissolve 1g of CS-WGA graft product powder prepared in S2 in 100g of dilute acetic acid aqueous solution (1% v / v) to prepare a 1% aqueous phase solution, which is used as wall material.

[0031] S5 Emulsion Preparation: Under high-speed shearing at 3000 rpm, 40 g of oil phase (S3) was slowly added to 60 g of 5% polyvinyl alcohol for emulsification for 5 min. 0.1% sodium stearate (for fragrance) was added, followed by slow pouring in 2.5 g of aqueous phase (S4). After uniform dispersion, 1 g of sodium tripolyphosphate aqueous solution (10%) was added dropwise. The mixture was stirred at 500 rpm for 2 h. 25% sodium hydroxide was added, and the mixture was stirred at 500 rpm for 2 h. After the encapsulation was completed, a stable O / W type emulsion was formed with a particle size of 16.20 μm, thus obtaining the pH-responsive mold-targeted controlled-release Artemisia argyi fragrance microcapsule emulsion for daily chemical use.

[0032] Example 3 A method for preparing pH-responsive mold-targeted controlled-release microcapsules for daily chemical use, comprising the following steps: Preparation of S1 polyacrylic acid chitosan: Weigh 5.0 g of chitosan (degree of deacetylation ≥ 90%) and dissolve it in 10% glacial acetic acid solution. Disperse the solution into a clear solution at 50℃ and 500 rpm. Purge nitrogen gas to remove oxygen for 15 min, add 0.1 g APS and 4 mL acrylic acid, and react at 60℃ for 3 h. After the reaction is complete, put the mixed solution into a dialysis bag and dialyze it in flowing pure water for 48 h to remove unreacted small molecules and monomers, finally obtaining polyacrylic acid chitosan.

[0033] Preparation of S2 CS-WGA grafted product: 5g of the polyacrylic acid chitosan product prepared in S1 was dissolved in a 15% glacial acetic acid solution, and 0.15g of NHS was added. The mixture was stirred at room temperature for 30 min. Subsequently, 15g of WGA in PBS solution (pH=7.4) was added dropwise, and the mixture was slowly stirred at 4℃ for 24 h to allow the amino groups of WGA to undergo an amidation reaction with the activated carboxyl groups of chitosan, forming a conjugate. The reaction solution was dialyzed and freeze-dried to obtain CS-WGA grafted product powder.

[0034] Preparation of S3 oil phase: 20g of cinnamon-orange peel blended essential oil was dissolved in 100g of isopropyl myristate and stirred evenly at 300rpm at room temperature to prepare a 20% mass concentration cinnamon-orange peel fragrance.

[0035] Preparation of S4 aqueous phase: Dissolve 1g of CS-WGA graft product powder prepared in S2 in 100g of dilute acetic acid aqueous solution (1% v / v) to prepare a 1% aqueous phase solution, which is used as wall material.

[0036] S5 emulsion preparation: Under high-speed shearing at 3000 rpm, 80 g of oil phase (S3) was slowly added to 120 g of 5% SMA for emulsification for 3 min. 0.1% calcium silicate for fragrance was added, followed by slow pouring in 5 g of aqueous phase (S4). After uniform dispersion, 2 g of sodium tripolyphosphate aqueous solution (10%) was added dropwise. The mixture was stirred at 500 rpm for 2 h. 25% potassium hydroxide was added, and the mixture was stirred at 500 rpm for 2 h. After the encapsulation was completed, a stable O / W type emulsion was formed with a particle size of 14.98 μm, which yielded the pH-responsive mold-targeted controlled-release cinnamon-orange peel fragrance microcapsule emulsion for daily chemical use.

[0037] Example 4 A method for preparing pH-responsive mold-targeted controlled-release microcapsules for daily chemical use, comprising the following steps: S1. Preparation of polyacrylic acid chitosan: Weigh 50.0 g of chitosan (degree of deacetylation ≥ 90%) and dissolve it in 10% citric acid solution. Disperse the solution into a transparent solution at 50℃ and 500 rpm. Purge nitrogen gas to remove oxygen for 15 min, add 10 g of hydrogen peroxide and 40 mL of acrylic acid, and react at 60℃ for 3 h. After the reaction is complete, put the mixed solution into a dialysis bag and dialyze it in flowing pure water for 48 h to remove unreacted small molecules and monomers, finally obtaining polyacrylic acid chitosan.

[0038] S2. Preparation of grafted product: 50g of the polyacrylic acid chitosan product prepared in S1 was dissolved in a 15% citric acid solution, and 1.5g of bis(succinimide) octanoate was added. The mixture was stirred at room temperature for 30 min. Subsequently, 250g of C-type lectin in PBS solution (pH=7.4) was added dropwise, and the mixture was slowly stirred at 4℃ for 24 h. The reaction solution was dialyzed and freeze-dried to obtain the grafted product powder for later use.

[0039] S3. Preparation of the oil phase: Dissolve 25g of Forsythia essential oil in 100g of IPM and stir evenly at 300rpm at room temperature to prepare a 25% mass concentration of Forsythia fragrance.

[0040] S4. Preparation of aqueous phase: Dissolve 2g of graft product powder prepared in S2 in 100g of dilute acetic acid aqueous solution (1% v / v) to prepare a 2% aqueous phase solution, which is used as wall material.

[0041] S5. Emulsion preparation: Under high-speed shearing at 3000 rpm, 160 g of oil phase (S3) was slowly added to 240 g of 5% SMA for emulsification for 3 min. 0.1% sodium stearate (for fragrance) was added, followed by slow pouring in 10 g of aqueous phase (S4). After uniform dispersion, 4 g of sodium tripolyphosphate aqueous solution (10%) was added dropwise. The mixture was stirred at 500 rpm for 2 h. 25% potassium hydroxide was added, and the mixture was stirred at 500 rpm for 2 h. After the encapsulation was completed, a stable O / W type emulsion was formed with a particle size of 16.35 μm, thus obtaining the pH-responsive mold-targeted controlled-release forsythia fragrance microcapsule emulsion for daily chemical use.

[0042] Example 5 A method for preparing pH-responsive mold-targeted controlled-release microcapsules for daily chemical use, comprising the following steps: Preparation of S1 polyacrylic acid chitosan: Weigh 5.0 g of chitosan (degree of deacetylation ≥ 90%) and dissolve it in 10% hydrochloric acid solution. Disperse the solution into a clear solution at 50℃ and 500 rpm. Purge with nitrogen to remove oxygen for 15 min, add 0.1 g APS and 4 mL acrylic acid, and react at 60℃ for 3 h. After the reaction is complete, put the mixed solution into a dialysis bag and dialyze it in flowing pure water for 48 h to remove unreacted small molecules and monomers, finally obtaining polyacrylic acid chitosan.

[0043] Preparation of S2 CS-WGA grafted product: 5g of the polyacrylic acid chitosan product prepared in S1 was dissolved in a 15% glacial acetic acid solution, and 0.15g of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride was added. The mixture was stirred at room temperature for 30 min. Subsequently, 15g of WGA in PBS solution (pH=7.4) was added dropwise, and the mixture was slowly stirred at 4℃ for 24 h to allow the amino groups of WGA to undergo an amidation reaction with the carboxyl groups of the activated chitosan, forming a conjugate. The reaction solution was dialyzed and freeze-dried to obtain CS-WGA grafted product powder.

[0044] Preparation of S3 oil phase: 20g of cinnamon-orange peel blended essential oil was dissolved in 100g of isopropyl myristate and stirred evenly at 300rpm at room temperature to prepare a 20% mass concentration cinnamon-orange peel fragrance.

[0045] Preparation of S4 aqueous phase: Dissolve 1g of CS-WGA graft product powder prepared in S2 in 100g of dilute acetic acid aqueous solution (1% v / v) to prepare a 1% aqueous phase solution, which is used as wall material.

[0046] S5 emulsion preparation: Under high-speed shearing at 3000 rpm, 80 g of oil phase (S3) was slowly added to 120 g of 5% polyvinyl alcohol for emulsification for 3 min. 0.1% sodium stearate (for fragrance) was added, followed by slow pouring in 5 g of aqueous phase (S4). After uniform dispersion, 2 g of sodium tripolyphosphate aqueous solution (10%) was added dropwise. The mixture was stirred at 500 rpm for 2 h. 25% potassium hydroxide was added, and the mixture was stirred at 500 rpm for 2 h. After the encapsulation was completed, a stable O / W type emulsion was formed with a particle size of 17.65 μm, thus obtaining the pH-responsive mold-targeted controlled-release cinnamon-orange peel fragrance microcapsule emulsion for daily chemical use.

[0047] Example 6 A method for preparing pH-responsive mold-targeted controlled-release microcapsules for daily chemical use, comprising the following steps: S1. Preparation of polyacrylic acid chitosan: Weigh 50.0 g of chitosan (degree of deacetylation ≥ 90%) and dissolve it in 15% glacial acetic acid solution. Disperse the solution into a transparent solution at 50℃ and 500 rpm. Purge nitrogen gas to remove oxygen for 15 min, add 10 g of APS and 10 mL of acrylic acid, and react at 60℃ for 3 h. After the reaction is complete, put the mixed solution into a dialysis bag and dialyze it in flowing pure water for 48 h to remove unreacted small molecules and monomers, finally obtaining polyacrylic acid chitosan.

[0048] S2. Preparation of CS-WGA grafted product: 50g of the polyacrylic acid chitosan product prepared in S1 was dissolved in a 5% glacial acetic acid solution, and 1.5g of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride was added. The mixture was stirred at room temperature for 30 min. Subsequently, 250g of WGA in PBS solution (pH=7.4) was added dropwise, and the mixture was slowly stirred at 4℃ for 24 h to allow the amino groups of WGA to undergo an amidation reaction with the carboxyl groups of the activated chitosan, forming a conjugate. The reaction solution was dialyzed and freeze-dried to obtain CS-WGA grafted product powder.

[0049] S3. Preparation of the oil phase: Dissolve 25g of Forsythia essential oil in 100g of soybean oil and stir evenly at 300rpm at room temperature to prepare a 25% mass concentration of Forsythia fragrance.

[0050] S4. Preparation of aqueous phase: Dissolve 2g of CS-WGA graft product powder prepared in S2 in 100g of dilute acetic acid aqueous solution (1% v / v) to prepare a 2% aqueous phase solution, which is used as wall material.

[0051] S5. Emulsion preparation: Under high-speed shearing at 3000 rpm, 160 g of oil phase (S3) was slowly added to 240 g of 5% SMA for emulsification for 3 min. 0.1% sodium stearate (for fragrance) was added, followed by slow pouring in 10 g of aqueous phase (S4). After uniform dispersion, 4 g of sodium tripolyphosphate aqueous solution (10%) was added dropwise. The mixture was emulsified at 500 rpm for 2 h. 25% potassium hydroxide was added, and the mixture was emulsified at 500 rpm for 2 h. After the encapsulation was completed, a stable O / W type emulsion was formed with a particle size of 16.30 μm, thus obtaining the pH-responsive mold-targeted controlled-release forsythia fragrance microcapsule emulsion for daily chemical use.

[0052] Comparative Example 1 Based on Example 2, but with the wall material changed from CS-WGA grafted product powder to chitosan, the remaining steps are the same as in Example 2.

[0053] S1. Preparation of the oil phase: Dissolve 10g of Artemisia argyi essential oil in 100g of corn oil and stir evenly at 200rpm at room temperature to prepare Artemisia argyi fragrance with a mass concentration of 10%.

[0054] S2. Preparation of the aqueous phase: Dissolve 1g of chitosan powder in 100g of dilute acetic acid aqueous solution (1% v / v) to prepare a 1% aqueous phase solution, which will be used as the wall material.

[0055] S3. Emulsion preparation: Under high-speed shearing at 3000 rpm, 40 g of oil phase (S1) was slowly added to 60 g of 5% Tween 80 for emulsification for 5 minutes. 0.1% sodium stearate (for fragrance) was added, followed by slow pouring in 2.5 g of aqueous phase (S2). After uniform dispersion, 1 g of sodium tripolyphosphate aqueous solution (10%) was added dropwise. The mixture was stirred at 500 rpm for 2 hours. 25% sodium hydroxide was added, and the mixture was stirred at 500 rpm for 2 hours. After the encapsulation was completed, a stable O / W type emulsion was formed with a particle size of 17.02 μm, thus obtaining the Artemisia argyi fragrance microcapsule emulsion.

[0056] Comparative Example 2 Based on Example 2, the only difference is the omission of step S2. Artemisia argyi fragrance microcapsule emulsion was prepared using polyacrylic acid chitosan as the wall material.

[0057] Comparative Example 3 Based on Example 2, the only difference is that steps S1 and S2 are omitted, and WGA is directly grafted onto chitosan. Artemisia argyi flavor microcapsule emulsion is prepared. Comparative Example 4 Based on Example 1, the only difference is that in S2, the crosslinking agent is replaced with N,N'-carboxydiimidazole for grafting WGA.

[0058] Take 10g of each of the microcapsules prepared in the above examples and comparative examples, dissolve them in equal volumes of solutions with different pH values, and test their pH response characteristics. Simultaneously, take 0.3g of each of the microcapsules from the above examples and comparative examples, prepare a 0.1% concentration microcapsule laundry detergent, add 10g of the detergent to a 10L washing machine to wash cotton fabric, and test the antibacterial effect after drying. See Table 1 for details.

[0059] Table 1

[0060] Note: The lower the pH, the greater the swelling rate, and the higher the release rate, the better the effect; the higher the antibacterial rate, the stronger the antibacterial effect.

[0061] As shown in Table 1 of Examples 1-4, the response speed increases with increasing acidity, and the release effect becomes stronger. Examples 2 and 1 show that, compared to chitosan, CS-WGA grafted products, as microcapsule shell materials, are more sensitive to acidity, enabling pH response in acidic mold environments, rapid release of antibacterial fragrance, and enhanced antibacterial effect. Examples 2, 2, and 3 show that the microcapsules in Comparative Example 2 using polyacrylic acid chitosan as the shell material only exhibited pH response performance in acidic environments, lacking specific targeting characteristics against mold. In Comparative Example 3, the microcapsules using chitosan-branched WGA as the shell material did not show excellent pH response release performance, but demonstrated superior mold targeting performance compared to Comparative Example 2, achieving high-efficiency antibacterial ability even under low-concentration antibacterial fragrance release conditions. Therefore, using CS-WGA grafted products as microcapsule shell materials can achieve pH response in acidic mold environments, precisely and rapidly releasing antibacterial fragrance, greatly enhancing the antibacterial effect. As can be seen from Example 1 and Comparative Example 4, compared with N,N'-carboxydiimidazole as a crosslinking agent, N-hydroxysuccinimide as a crosslinking agent has stronger reactivity, produces a shell material with stronger mold targeting, and shows a stronger antibacterial effect.

[0062] In summary, the microcapsules prepared by this invention have the ability to specifically identify and target mold and the pH-responsive release ability of polyacrylic acid chitosan. They can accurately release natural fragrances with both antibacterial and aromatic functions at the mold-bearing parts of clothing, achieving the dual effects of antibacterial and fragrance retention.

[0063] The above embodiments describe preferred embodiments of the present invention, but the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other way. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A method for preparing pH-responsive mold-targeted controlled-release fragrance microcapsules for daily chemical use, characterized in that, Includes the following steps: S1. Dissolve chitosan in an acidic solution, add a catalyst and pH-sensitive reagent under a protective atmosphere to react, and separate and purify to obtain the pH-responsive graft copolymer. S2. The pH-responsive graft copolymer, crosslinking agent and mold-targeting reagent are mixed and reacted, and the microcapsule wall material is obtained after dialysis purification. S3. The fragrance is emulsified with an emulsifier, and then an antifoaming agent, microcapsule wall material, sodium tripolyphosphate aqueous solution and pH adjuster are added to prepare pH-responsive mold-targeted controlled-release fragrance microcapsules for daily chemical use.

2. The preparation method according to claim 1, characterized in that: The acidic solution described in S1 is one of hydrochloric acid, citric acid, acetic acid, sulfuric acid, carbonic acid, and lactic acid with a mass concentration of 1-20 wt%; the catalyst is one of hydrogen peroxide, sodium peroxide, peracetic acid, potassium peroxide, calcium peroxide, ammonium persulfate, potassium persulfate, and sodium persulfate; and the pH-sensitive reagent is one of acrylic acid, glyoxylic acid, chloroalkyl acid, phenylboronic acid, and 4-vinylpyridine.

3. The preparation method according to claim 1, characterized in that: The mass ratio of chitosan to pH-sensitive reagent is 1:0.1~7.

4. The preparation method according to claim 1, characterized in that: The reaction temperature in S1 is 40℃~100℃, and the reaction time is 0.5h~8h. After the reaction, one or more of the following methods are used for separation and purification: filtration, recrystallization, dialysis, column chromatography and extraction.

5. The preparation method according to claim 1, characterized in that: The crosslinking agent in S2 is one or more of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride, bis(succinimide) octanoate, dithiosuccinimide propionate, maleimide acetate succinimide ester, pentafluorophenol biotin ester, glutaric acid succinimide ester, and N-hydroxysuccinimide; the mold targeting agent is one of wheat germ lectin, 1,8-dihydroxynaphthalene melanin, C-type lectin, biphenyl, o-phenylphenol, and 2-pyridinium thiol-1-zinc oxide.

6. The preparation method according to claim 1, characterized in that: In S2, the mass ratio of pH-responsive graft copolymer, crosslinking agent, and mold-targeting reagent is 1:0.01~1:0.2~4.

7. The preparation method according to claim 1, characterized in that: In S2, the pH-responsive graft copolymer and the mold-targeting reagent are mixed at a temperature below 4°C for 12-24 hours.

8. The preparation method according to claim 1, characterized in that: The emulsifier in S3 is one or more of the following: sodium stearate, sodium dodecyl sulfate, calcium dodecylbenzene sulfonate, Tween, gum arabic, styrene-maleic anhydride copolymer, polyoxyethylene ether, polyoxypropylene ether, polyvinyl alcohol, and lecithin; the defoamer is one or more of the following: sodium stearate, stearamide, potassium tartrate, magnesium silicate, and calcium silicate; and the pH adjuster is one or more of the following: calcium hydroxide, potassium hydroxide, sodium hydroxide, fumaric acid, metatartaric acid, adipic acid, and hydrochloric acid.

9. The preparation method according to any one of claims 1 to 8, characterized in that: The flavoring is one or more of the following: orange peel flavoring, mugwort flavoring, clove flavoring, eucommia flavoring, cinnamon flavoring, astragalus flavoring, and bamboo leaf flavoring.

10. pH-responsive mold-targeted controlled-release fragrance microcapsules for daily chemical use, prepared by any one of claims 1 to 9.

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