Organic-inorganic hybrid slow-release essence microcapsule and preparation method thereof

Abstract

The invention relates to the technical field of microcapsules, in particular to an organic-inorganic hybrid slow-release essence microcapsule and a preparation method thereof. The invention discloses an essential oil silane coupling agent which comprises the following components in percentage by weight: 10-35% of essential oil, 1-10% of a silane precursor, 0.01-2% of a silane coupling agent, 1-15% of polyisocyanate, 0.01-10% of an emulsifier, 0.01-10% of a polyamine compound and the balance of deionized water. Through the combination of sol-gel and interfacial polymerization methods, the stability of the essence is improved, so that the essence is not easy to volatilize or decompose after being stored for a long time or in different environments, the essence is effectively prevented from being in direct contact with air, and the lasting time of the fragrance is prolonged; in the using process of the organic-inorganic hybrid essence microcapsule, active substances are released in a slow release mode through the microcapsule, and environmental pollution and diffusion can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of microcapsules, and in particular to an organic-inorganic hybrid sustained-release essence microcapsule and a preparation method thereof. Background Art

[0002] Fragrances have pleasant smells, can eliminate odors, and improve people's quality of life. They are widely used in daily chemicals, food, health care, textiles and clothing, etc., but flavors are generally highly volatile substances with low boiling point, high volatility, short fragrance retention time, and chemical reactivity. The preservation of flavors and the stability of added products have become an important topic of general concern. Fragrance microencapsulation is to wrap raw materials such as flavors and plant essential oils with special materials and scientific methods through modern scientific and technological means to form microcapsule emulsions. This technology uses the sealing effect of the capsule wall to effectively inhibit the volatilization loss of flavors and improve the stability of storage and use of flavors. Due to the limitations of flavor properties, use environment, etc., the choice of shell materials is often relatively narrow. The existing technology has suitable shell materials such as chitosan-arabic gum, lecithin, starch, cellulose, etc., which are prepared. There are problems such as low coating efficiency, poor stability, and low fragrance loading. Fragrance microcapsules prepared by organic polymers such as polyurea and polyurethane have the problem of poor fragrance retention.

[0003] Chinese invention patent CN106281676A discloses a microcapsule sustained-release flavor, wherein the flavor is filled in the porous structure of the nano core material, and the coating material wraps the nano core material filled with the flavor to form a microcapsule sustained-release flavor; the composition and content of the microcapsule sustained-release flavor are as follows by weight: 5-15 parts of nano core material, 5-15 parts of flavor, 70-90 parts of coating material; the nano core material is porous resin or nano silicon dioxide; the coating material is pharmaceutical-grade PEG or monoglyceride. The microcapsule sustained-release flavor provided by the invention has a simple preparation method and environmentally friendly raw materials, but has defects such as poor shell formation, porous structure, and poor retention of low molecular weight flavor active ingredients. Summary of the invention

[0004] The first aspect of the present invention provides an organic-inorganic hybrid sustained-release flavor microcapsule, which comprises, by weight percentage, 10-35% of essential oil, 1-10% of silane precursor, 0.01-2% of silane coupling agent, 1-15% of polyisocyanate, 0.01-10% of emulsifier, 0.01-10% of polyamine compound, and the balance is made up of deionized water.

[0005] Preferably, the components include, by weight percentage: 20-35% essential oil, 1-4% silane precursor, 0.2-2% silane coupling agent, 1-6% polyisocyanate, 0.5-3% emulsifier, 0.5-2% polyamine compound, and deionized water to make up the balance.

[0006] Preferably, the content of the essential oil in the suspension of microcapsules is 20-30wt%.

[0007] Further preferably, the content of the essential oil in the suspension of microcapsules is 22-26 wt %.

[0008] Preferably, the weight ratio of the silane precursor to the silane coupling agent is 2:(0.2-2).

[0009] Further preferably, the weight ratio of the silane precursor to the silane coupling agent is 2:(0.2-1.5).

[0010] The weight ratio of the polyisocyanate to the polyamine compound is (4-4.5):(0.5-2).

[0011] Preferably, the weight ratio of the polyisocyanate to the polyamine compound is (4-4.5): (0.8-1).

[0012] The research in this application found that by limiting the weight ratio of polyisocyanate and polyamine compounds to (4-4.5): (0.5-2), the uniformity of capsule shell particle size and heat stability can be improved. It may be that the addition of polyamine can not only react with isocyanate to form a polymer shell, but also catalyze the hydrolysis-condensation reaction of the precursor and the silane coupling agent to form a silica shell layer on the droplet surface. The two reactions proceed simultaneously to form a specific organic-inorganic shell layer.

[0013] The essential oil includes at least one of lavender essence, apple essence, rose essence, lemon essence and fresh ocean essence.

[0014] The silane precursor includes one or more of tetraethyl silicate, tetramethoxysilane, tetrapropyl silicate, tetramethylsilane, polydimethylsiloxane, polymethylsiloxane, and polyethyl silicate.

[0015] Preferably, the silane precursor includes tetraethyl silicate and / or tetramethoxysilane.

[0016] The silane coupling agent includes one or more of methyltrimethoxysilane, methyltriethoxysilane, 3-aminopropyltriethoxysilane, and γ-aminopropylmethyldiethoxysilane.

[0017] Preferably, the silane coupling agent includes methyltrimethoxysilane and / or 3-aminopropyltriethoxysilane.

[0018] The polyisocyanate includes one or more of isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, methylcyclohexane diisocyanate, trimethyl-1,6-hexamethylene diisocyanate, xylylene diisocyanate, methylcyclohexyl diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate dimer, hexamethylene diisocyanate trimer, hexamethylene diisocyanate prepolymer, hexamethylene diisocyanate biuret, isophorone diisocyanate dimer, isophorone diisocyanate trimer, and diphenylmethane diisocyanate prepolymer.

[0019] Preferably, the polyisocyanate comprises isophorone diisocyanate and / or hexamethylene diisocyanate trimer.

[0020] The emulsifier includes one or more of polyvinyl alcohol, polyvinyl pyrrolidone, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, pectin, gum arabic, gelatin, Tween 80, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, phosphate, sodium polyacrylate, sodium carboxymethyl cellulose, dodecyl ammonium chloride, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, styrene maleic anhydride copolymer, polyacrylamide, dimethyl diallyl ammonium chloride homopolymer, acrylamide and diallyldimethylammonium chloride copolymer, and ethoxylated alkyl sodium sulfate.

[0021] Preferably, the emulsifier comprises polyvinyl alcohol and / or cetyltrimethylammonium bromide.

[0022] Preferably, the polyvinyl alcohol comprises one of the following brands: PVA-217e from Kuraray Co., Ltd., Japan; 088-10 (1788) from Guangzhou Zhonggao Chemical Co., Ltd.; eT-350 from Shanghai Xiangpu-Mitsubishi Chemical; Pertex8850 from Tianjin Xindema Group Co., Ltd.; Pertex9213 from Tianjin Xindema Group Co., Ltd. The polyamine compound includes one or more of hexamethylenediamine, ethylenediamine, tetramethylethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, hexamethylenetetramine, diethylenetriamine, tris(2-aminoethyl)amine, dicyclohexylmethanediamine, methylcyclohexanediamine, 2,2-dimethyl-1,3-propylenediamine, 1,3-cyclohexane dimethylenediamine, 1,2-diaminopropane, o-phenylenediamine, p-phenylenediamine, m-phenylenediamine, and polyethyleneimine.

[0023] Preferably, the polyamine compound comprises 1,2-diaminopropane and / or polyethyleneimine.

[0024] Preferably, the polyethyleneimine comprises one of the following brands: SP-006, SP-012, SP-018 of Shanghai Hanluo New Materials Co., Ltd.; GBK-PEI900, GBK-PEI7010 of Topk New Materials Technology (Shanghai) Co., Ltd.

[0025] The second aspect of the present invention provides a method for preparing organic-inorganic hybrid sustained-release flavor microcapsules, comprising the following steps: A silane precursor and a silane coupling agent are mixed, and pre-hydrolyzed with 15% to 25% by weight of deionized water to obtain a mixed solution; The polyisocyanate and the essential oil are stirred and mixed to form an oil phase, 20% to 30% by weight of deionized water is used to stir and dissolve the emulsifier to form a first aqueous phase, and the remaining deionized water is used to stir and dissolve the polyamine compound to form a second aqueous phase; The oil phase is added to the mixed solution, and then the first water phase is added, homogenized and emulsified to form an emulsion, and the second water phase is added dropwise to the emulsion, and the temperature is raised to react to obtain a microcapsule suspension containing essential oil; After the reaction is completed, the product is cooled, washed with water, filtered and dried to obtain the essence microcapsules.

[0026] The heating includes heating in steps, specifically including: the initial temperature is 20-35°C, each heating is 8-12°C, and the temperature is kept for 0.75-1.5h until the temperature reaches 50-70°C.

[0027] Preferably, the initial temperature is 30-35°C, and the temperature is kept for 0.75-1.5h every time the temperature rises by 10°C, until the temperature reaches 60-70°C.

[0028] More preferably, the initial temperature is 30°C, and the temperature is increased by 10°C for 1 hour until the temperature reaches 60°C.

[0029] Beneficial Effects 1. By limiting the formula of essential oil 10-35%, silane precursor 1-10%, silane coupling agent 0.01-2%, polyisocyanate 1-15%, emulsifier 0.01-10%, polyamine compound 0.01-10%, and deionized water to make up the balance, safe, non-toxic, biocompatible, durable and stable microcapsules are obtained.

[0030] 2. By limiting the weight ratio of silane precursor to silane coupling agent to 2: (0.2-2), the fragrance loading can be increased to 20-30wt%.

[0031] 3. By limiting the weight ratio of polyisocyanate and polyamine compounds to (4-4.5): (0.5-2), the uniformity of the particle size and the heat stability of the capsule shell can be improved.

[0032] 4. Through the combination of sol-gel and interfacial polymerization methods, the stability of the flavor is improved, making it difficult for the flavor to evaporate or decompose during long-term storage or in different environments, effectively avoiding direct contact between the flavor and the air, thereby extending the duration of the aroma.

[0033] 5. The present application prepares organic-inorganic hybrid shells to encapsulate essential oils, which provide dual protection for volatile oily flavors, so that the flavor microcapsules can be used in the fields of daily necessities, personal care products, textiles, medicines, cosmetics, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a scanning electron microscope image of the microcapsules prepared in Example 1.

[0035] Figure 2 This is the thermal analysis (TGA) diagram of the microcapsules prepared in Example 1. DETAILED DESCRIPTION

[0036] Polyvinyl alcohol used in the examples: Guangzhou Zhonggao Chemical Co., Ltd., 088-10 (1788); polyethyleneimine: Shanghai Hanluo New Materials Co., Ltd. SP-012.

[0037] Example 1 An organic-inorganic hybrid sustained-release flavor microcapsule, comprising the following components, by weight percentage: 26% of essential oil (lavender flavor), 2% of silane precursor (tetraethyl silicate), 1% of silane coupling agent (methyltrimethoxysilane), 4% of polyisocyanate (hexamethylene diisocyanate trimer and isophorone diisocyanate in a weight ratio of 1:1), 1.2% of emulsifier (polyvinyl alcohol), 1% of polyamine compound (polyethyleneimine, molecular weight 1200), and the balance made up by deionized water.

[0038] A method for preparing organic-inorganic hybrid sustained-release essence microcapsules comprises the following steps: (1) mixing a silane precursor and a silane coupling agent, and pre-hydrolyzing them with deionized water to obtain a mixed solution; (2) stirring and mixing the polyisocyanate and the essential oil to form an oil phase, stirring and dissolving the emulsifier with deionized water to form a first aqueous phase, stirring and dissolving the polyamine compound with deionized water to form a second aqueous phase with a concentration of 10 wt % of the polyamine compound; (3) adding the oil phase to the mixed solution, and then adding the first water phase, homogenizing and emulsifying at 3000 rpm for 5 min to form an O / W emulsion, adding the second water phase dropwise to the emulsion under stirring at 500 rpm, heating and reacting for 24 h to obtain a microcapsule suspension containing essential oil; (4) After the reaction is completed, the mixture is cooled, washed with water, filtered and dried to obtain the flavor microcapsules.

[0039] The heating is carried out in steps, specifically: the initial temperature is 30°C, the temperature is increased by 10°C each time, and the temperature is kept for 1 hour until the temperature reaches 60°C.

[0040] Example 2 An organic-inorganic hybrid sustained-release flavor microcapsule, comprising the following components, by weight percentage: 22% of essential oil (lavender flavor), 2% of silane precursor (tetramethoxysilane), 1% of silane coupling agent (methyltrimethoxysilane), 4% of polyisocyanate (hexamethylene diisocyanate trimer and isophorone diisocyanate in a weight ratio of 1:1), 1.2% of emulsifier (polyvinyl alcohol), 1% of polyamine compound (polyethyleneimine, molecular weight 1200), and the balance made up by deionized water.

[0041] A method for preparing organic-inorganic hybrid sustained-release essence microcapsules comprises the following steps: (1) mixing a silane precursor and a silane coupling agent, and pre-hydrolyzing them with deionized water to obtain a mixed solution; (2) stirring and mixing the polyisocyanate and the essential oil to form an oil phase, stirring and dissolving the emulsifier with deionized water to form a first aqueous phase, stirring and dissolving the polyamine compound with deionized water to form a second aqueous phase with a concentration of 10 wt % of the polyamine compound; (3) adding the oil phase to the mixed solution, and then adding the first water phase, homogenizing and emulsifying at 3000 rpm for 5 min to form an O / W emulsion, adding the second water phase dropwise to the emulsion under stirring at 500 rpm, heating and reacting for 24 h to obtain a microcapsule suspension containing essential oil; (4) After the reaction is completed, the mixture is cooled, washed with water, filtered and dried to obtain the flavor microcapsules.

[0042] The heating is carried out in steps, specifically: the initial temperature is 30°C, the temperature is increased by 10°C each time, and the temperature is kept for 1 hour until the temperature reaches 60°C.

[0043] Example 3 An organic-inorganic hybrid sustained-release flavor microcapsule, comprising the following components, by weight percentage: 22% of essential oil (lavender flavor), 2% of silane precursor (tetraethyl silicate), 1.5% of silane coupling agent (methyltrimethoxysilane), 4% of polyisocyanate (hexamethylene diisocyanate trimer and isophorone diisocyanate in a weight ratio of 1:1), 1.2% of emulsifier (polyvinyl alcohol), 1% of polyamine compound (polyethyleneimine, molecular weight 1200), and the balance made up by deionized water.

[0044] A method for preparing organic-inorganic hybrid sustained-release essence microcapsules comprises the following steps: (1) mixing a silane precursor and a silane coupling agent, and pre-hydrolyzing them with deionized water to obtain a mixed solution; (2) stirring and mixing the polyisocyanate and the essential oil to form an oil phase, stirring and dissolving the emulsifier with deionized water to form a first aqueous phase, stirring and dissolving the polyamine compound with deionized water to form a second aqueous phase with a concentration of 10 wt % of the polyamine compound; (3) adding the oil phase to the mixed solution, and then adding the first water phase, homogenizing and emulsifying at 3000 rpm for 5 min to form an O / W emulsion, adding the second water phase dropwise to the emulsion under stirring at 500 rpm, heating and reacting for 24 h to obtain a microcapsule suspension containing essential oil; (4) After the reaction is completed, the mixture is cooled, washed with water, filtered and dried to obtain the flavor microcapsules.

[0045] The heating is carried out in steps, specifically: the initial temperature is 30°C, the temperature is increased by 10°C each time, and the temperature is kept for 1 hour until the temperature reaches 60°C.

[0046] Example 4 An organic-inorganic hybrid sustained-release flavor microcapsule, comprising the following components, by weight percentage: 22% of essential oil (lavender flavor), 2% of silane precursor (tetraethyl silicate), 1% of silane coupling agent (methyltrimethoxysilane), 4% of polyisocyanate (hexamethylene diisocyanate trimer and isophorone diisocyanate in a weight ratio of 1:1), 1% of emulsifier (hexadecyltrimethylammonium bromide), 1% of polyamine compound (polyethyleneimine, molecular weight 1200), and the balance made up by deionized water.

[0047] A method for preparing organic-inorganic hybrid sustained-release essence microcapsules comprises the following steps: (1) mixing a silane precursor and a silane coupling agent, and pre-hydrolyzing them with deionized water to obtain a mixed solution; (2) stirring and mixing the polyisocyanate and the essential oil to form an oil phase, stirring and dissolving the emulsifier with deionized water to form a first aqueous phase, stirring and dissolving the polyamine compound with deionized water to form a second aqueous phase with a concentration of 10 wt % of the polyamine compound; (3) adding the oil phase to the mixed solution, and then adding the first water phase, homogenizing and emulsifying at 3000 rpm for 5 min to form an O / W emulsion, adding the second water phase dropwise to the emulsion under stirring at 500 rpm, heating and reacting for 24 h to obtain a microcapsule suspension containing essential oil; (4) After the reaction is completed, the mixture is cooled, washed with water, filtered and dried to obtain the flavor microcapsules.

[0048] The heating is carried out in steps, specifically: the initial temperature is 30°C, the temperature is increased by 10°C each time, and the temperature is kept for 1 hour until the temperature reaches 60°C.

[0049] Example 5 An organic-inorganic hybrid sustained-release flavor microcapsule, comprising the following components, by weight percentage: 22% of essential oil (lavender flavor), 2% of silane precursor (tetraethyl silicate), 1% of silane coupling agent (methyltrimethoxysilane), 4% of polyisocyanate (hexamethylene diisocyanate trimer and isophorone diisocyanate in a weight ratio of 1:1), 1% of emulsifier (hexadecyltrimethylammonium bromide), 0.8% of polyamine compound (1,2-diaminopropane), and the balance made up of deionized water.

[0050] A method for preparing organic-inorganic hybrid sustained-release essence microcapsules comprises the following steps: (1) mixing a silane precursor and a silane coupling agent, and pre-hydrolyzing them with deionized water to obtain a mixed solution; (2) stirring and mixing the polyisocyanate and the essential oil to form an oil phase, stirring and dissolving the emulsifier with deionized water to form a first aqueous phase, stirring and dissolving the polyamine compound with deionized water to form a second aqueous phase with a concentration of 10 wt % of the polyamine compound; (3) adding the oil phase to the mixed solution, and then adding the first water phase, homogenizing and emulsifying at 3000 rpm for 5 min to form an O / W emulsion, adding the second water phase dropwise to the emulsion under stirring at 500 rpm, heating and reacting for 24 h to obtain a microcapsule suspension containing essential oil; (4) After the reaction is completed, the mixture is cooled, washed with water, filtered and dried to obtain the flavor microcapsules.

[0051] The heating is carried out in steps, specifically: the initial temperature is 30°C, the temperature is increased by 10°C each time, and the temperature is kept for 1 hour until the temperature reaches 60°C.

[0052] Example 6 An organic-inorganic hybrid sustained-release flavor microcapsule, comprising, by weight percentage, 22% of essential oil (lavender flavor), 2% of silane precursor (tetraethyl silicate), 0.2% of silane coupling agent (methyltrimethoxysilane), 4.5% of polyisocyanate (hexamethylene diisocyanate trimer and isophorone diisocyanate in a weight ratio of 2.5:2), 1.2% of emulsifier (polyvinyl alcohol), 1% of polyamine compound (polyethyleneimine, molecular weight 1200), and the balance made up by deionized water.

[0053] A method for preparing organic-inorganic hybrid sustained-release essence microcapsules comprises the following steps: (1) mixing a silane precursor and a silane coupling agent, and pre-hydrolyzing them with deionized water to obtain a mixed solution; (2) stirring and mixing the polyisocyanate and the essential oil to form an oil phase, stirring and dissolving the emulsifier with deionized water to form a first aqueous phase, stirring and dissolving the polyamine compound with deionized water to form a second aqueous phase with a concentration of 5 wt % of the polyamine compound; (3) adding the oil phase to the mixed solution, and then adding the first water phase, homogenizing and emulsifying at 3000 rpm for 5 min to form an O / W emulsion, adding the second water phase dropwise to the emulsion under stirring at 500 rpm, heating and reacting for 24 h to obtain a microcapsule suspension containing essential oil; (4) After the reaction is completed, the mixture is cooled, washed with water, filtered and dried to obtain the flavor microcapsules.

[0054] The heating is carried out in steps, specifically: the initial temperature is 30°C, the temperature is increased by 10°C each time, and the temperature is kept for 1 hour until the temperature reaches 60°C.

[0055] Example 7 An organic-inorganic hybrid sustained-release flavor microcapsule, comprising the following components, measured by weight percentage: 22% of essential oil (lavender flavor), 2% of silane precursor (tetraethyl silicate), 0.2% of silane coupling agent (3-aminopropyltriethoxysilane), 4.5% of polyisocyanate (hexamethylene diisocyanate trimer and isophorone diisocyanate in a weight ratio of 2.5:2), 1% of emulsifier (hexadecyltrimethylammonium bromide), 0.8% of polyamine compound (polyethyleneimine, molecular weight 1200), and the balance made up by deionized water.

[0056] A method for preparing organic-inorganic hybrid sustained-release essence microcapsules comprises the following steps: (1) mixing a silane precursor and a silane coupling agent, and pre-hydrolyzing them with deionized water to obtain a mixed solution; (2) stirring and mixing the polyisocyanate and the essential oil to form an oil phase, stirring and dissolving the emulsifier with deionized water to form a first aqueous phase, stirring and dissolving the polyamine compound with deionized water to form a second aqueous phase with a concentration of 5 wt % of the polyamine compound; (3) adding the oil phase to the mixed solution, and then adding the first water phase, homogenizing and emulsifying at 3000 rpm for 5 min to form an O / W emulsion, adding the second water phase dropwise to the emulsion under stirring at 500 rpm, heating and reacting for 24 h to obtain a microcapsule suspension containing essential oil; (4) After the reaction is completed, the mixture is cooled, washed with water, filtered and dried to obtain the flavor microcapsules.

[0057] The heating is carried out in steps, specifically: the initial temperature is 30°C, the temperature is increased by 10°C each time, and the temperature is kept for 1 hour until the temperature reaches 60°C.

[0058] Example 8 An organic-inorganic hybrid sustained-release flavor microcapsule, comprising the following components, measured by weight percentage: 22% of essential oil (lavender flavor), 2% of silane precursor (tetraethyl silicate), 0.2% of silane coupling agent (3-aminopropyltriethoxysilane), 4.5% of polyisocyanate (hexamethylene diisocyanate trimer and isophorone diisocyanate in a weight ratio of 2.5:2), 1% of emulsifier (hexadecyltrimethylammonium bromide), 0.8% of polyamine compound (1,2-diaminopropane), and the balance made up of deionized water.

[0059] A method for preparing organic-inorganic hybrid sustained-release essence microcapsules comprises the following steps: (1) mixing a silane precursor and a silane coupling agent, and pre-hydrolyzing them with deionized water to obtain a mixed solution; (2) stirring and mixing the polyisocyanate and the essential oil to form an oil phase, stirring and dissolving the emulsifier with deionized water to form a first aqueous phase, stirring and dissolving the polyamine compound with deionized water to form a second aqueous phase with a concentration of 5 wt % of the polyamine compound; (3) adding the oil phase to the mixed solution, and then adding the first water phase, homogenizing and emulsifying at 3000 rpm for 5 min to form an O / W emulsion, adding the second water phase dropwise to the emulsion under stirring at 500 rpm, heating and reacting for 24 h to obtain a microcapsule suspension containing essential oil; (4) After the reaction is completed, the mixture is cooled, washed with water, filtered and dried to obtain the flavor microcapsules.

[0060] The heating is carried out in steps, specifically: the initial temperature is 30°C, the temperature is increased by 10°C each time, and the temperature is kept for 1 hour until the temperature reaches 60°C.

[0061] Example 9 An organic-inorganic hybrid sustained-release flavor microcapsule, comprising the following components, by weight percentage: 22% of essential oil (lavender flavor), 2% of silane precursor (tetraethyl silicate), 1% of silane coupling agent (3-aminopropyltriethoxysilane), 4% of polyisocyanate (hexamethylene diisocyanate trimer), 1.2% of emulsifier (hexadecyltrimethylammonium bromide), 1% of polyamine compound (polyethyleneimine, molecular weight 1200), and the balance made up by deionized water.

[0062] A method for preparing organic-inorganic hybrid sustained-release essence microcapsules comprises the following steps: (1) mixing a silane precursor and a silane coupling agent, and pre-hydrolyzing them with deionized water to obtain a mixed solution; (2) stirring and mixing the polyisocyanate and the essential oil to form an oil phase, stirring and dissolving the emulsifier with deionized water to form a first aqueous phase, stirring and dissolving the polyamine compound with deionized water to form a second aqueous phase with a concentration of 10 wt % of the polyamine compound; (3) adding the oil phase to the mixed solution, and then adding the first water phase, homogenizing and emulsifying at 3000 rpm for 5 min to form an O / W emulsion, adding the second water phase dropwise to the emulsion under stirring at 500 rpm, heating and reacting for 24 h to obtain a microcapsule suspension containing essential oil; (4) After the reaction is completed, the mixture is cooled, washed with water, filtered and dried to obtain the flavor microcapsules.

[0063] The heating is carried out in steps, specifically: the initial temperature is 30°C, the temperature is increased by 10°C each time, and the temperature is kept for 1 hour until the temperature reaches 60°C.

[0064] Example 10 An organic-inorganic hybrid sustained-release flavor microcapsule, comprising, by weight percentage, 22% of essential oil (lavender flavor), 2% of silane precursor (tetraethyl silicate), 1% of silane coupling agent (3-aminopropyltriethoxysilane), 4% of polyisocyanate (isophorone diisocyanate), 1.2% of emulsifier (hexadecyltrimethylammonium bromide), 1% of polyamine compound (polyethyleneimine, molecular weight 1200), and the balance made up by deionized water.

[0065] A method for preparing organic-inorganic hybrid sustained-release essence microcapsules comprises the following steps: (1) mixing a silane precursor and a silane coupling agent, and pre-hydrolyzing them with deionized water to obtain a mixed solution; (2) stirring and mixing the polyisocyanate and the essential oil to form an oil phase, stirring and dissolving the emulsifier with deionized water to form a first aqueous phase, stirring and dissolving the polyamine compound with deionized water to form a second aqueous phase with a concentration of 10 wt % of the polyamine compound; (3) adding the oil phase to the mixed solution, and then adding the first water phase, homogenizing and emulsifying at 3000 rpm for 5 min to form an O / W emulsion, adding the second water phase dropwise to the emulsion under stirring at 500 rpm, heating and reacting for 24 h to obtain a microcapsule suspension containing essential oil; (4) After the reaction is completed, the mixture is cooled, washed with water, filtered and dried to obtain the flavor microcapsules.

[0066] The heating is carried out in steps, specifically: the initial temperature is 30°C, the temperature is increased by 10°C each time, and the temperature is kept for 1 hour until the temperature reaches 60°C.

[0067] Comparative Example 1 A polyurea shell flavor microcapsule comprises the following raw materials in percentage by weight: 22 wt% of essential oil (lavender flavor), 5 wt% of isophorone diisocyanate, 0.8 wt% of sodium dodecyl sulfate, 1.0 wt% of polyethyleneimine (molecular weight 1200), and 71.2 wt% of deionized water.

[0068] The preparation method of the above essence microcapsules is as follows: (1) Stir isophorone diisocyanate and essence evenly to form an oil phase.

[0069] (2) Sodium dodecyl sulfate is added to deionized water to form a first aqueous phase; polyethyleneimine is added to deionized water to prepare a polyethyleneimine solution with a concentration of 10 wt % as a second aqueous phase for later use.

[0070] (3) Add the oil phase described in step (1) to the mixed solution of step (2), homogenize and emulsify at 3000 rpm for 5 minutes to form an O / W emulsion. Pour the emulsion into a flask, stir at 500 rpm, slowly add the polyethyleneimine solution dropwise, gradually raise the temperature to 70°C, stir and react for 12 hours to obtain polyurea flavor microcapsules.

[0071] Comparative Example 2 A sol-gel precursor is provided for preparing silica shell flavor microcapsules, which comprises the following raw materials in percentage by mass: 22 wt % of essential oil (lavender flavor), 5 wt % of tetraethyl silicate, 0.6 wt % of hexadecyltrimethylammonium chloride, and 72.4 wt % of deionized water.

[0072] The preparation method of the above essence microcapsules is as follows: (1) Add hexadecyltrimethylammonium chloride into deionized water to form an aqueous phase.

[0073] (2) Stir and mix the essential oil and tetraethyl silicate to form an oil phase.

[0074] (3) Add the oil phase to the water phase and stir evenly. Homogenize and emulsify at 3000 rpm for 5 min to form an O / W emulsion. Pour the emulsion into a flask, stir at 500 rpm, and react at 35°C for 48 h to obtain silica flavor microcapsules.

[0075] Performance testing methods and data The microcapsules prepared in Example 1 were characterized by electron microscopy and thermal analysis. Figure 1 As shown, the particle size distribution of microcapsules is uniform. Figure 2 As shown, the decomposition temperature of the microcapsules is about 300°C, which illustrates the synthesis of organic-inorganic hybrid sustained-release flavor microcapsules.

[0076] Evaluation of fragrance intensity: The sample was added to the base of unscented laundry detergent for evaluation: the fragrance microcapsule slurry (addition amount 0.5wt%) was added to the base and stirred evenly to obtain microcapsule laundry detergent. Take 20g of microcapsule laundry detergent, add 5L of water and pour into a small drum washing machine, put in a 40g 30×30cm cotton towel, wash according to the speed wash mode, put it on the clothes rack after dehydration, and dry it naturally in a clean, odor-free laboratory. Find 5 experimenters to check the fragrance of the towel on 1d, 2d, 3d, 4d, 5d, 6d, and 7d, and rub the towel (a small area) to score the fragrance intensity (5-point system: 1=very weak, 2=weak, 3=medium, 4=strong, 5=very strong), and the rubbing strength and number of times for each test should be consistent. The scores of 5 people were counted and the average value was calculated to obtain a comprehensive score. The fragrance intensity evaluation results obtained by testing the fragrance release are shown in Table 1.

[0077] Table 1

[0078] It can be seen from Table 1 that Examples 1-10 of the present application all achieved excellent fragrance 7 days before and after kneading.

Claims

1. An organic-inorganic hybrid sustained-release flavor microcapsule, characterized in that: Calculated by weight percentage, the components include: 20-35% essential oil, 1-4% silane precursor, 0.2-2% silane coupling agent, 1-6% polyisocyanate, 0.5-3% emulsifier, 0.5-2% polyamine compound, and deionized water to make up the balance.

2. The organic-inorganic hybrid sustained-release flavor microcapsule according to claim 1, characterized in that: The content of the essential oil in the suspension of microcapsules is 20-30wt%.

3. The organic-inorganic hybrid sustained-release flavor microcapsule according to claim 2, characterized in that: The weight ratio of the silane precursor to the silane coupling agent is 2:(0.2-2).

4. The organic-inorganic hybrid sustained-release flavor microcapsule according to claim 3, characterized in that: The weight ratio of the polyisocyanate to the polyamine compound is (4-4.5):(0.5-2).

5. The organic-inorganic hybrid sustained-release flavor microcapsule according to claim 1 or 4, characterized in that: The silane precursor includes one or more of tetraethyl silicate, tetramethoxysilane, tetrapropyl silicate, tetramethylsilane, polydimethylsiloxane, polymethylsiloxane, and polyethyl silicate.

6. The organic-inorganic hybrid sustained-release flavor microcapsule according to claim 5, characterized in that: The silane coupling agent includes one or more of methyltrimethoxysilane, methyltriethoxysilane, 3-aminopropyltriethoxysilane, and γ-aminopropylmethyldiethoxysilane.

7. The organic-inorganic hybrid sustained-release flavor microcapsule according to claim 1 or 6, characterized in that: The polyisocyanate includes one or more of isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, methylcyclohexane diisocyanate, trimethyl-1,6-hexamethylene diisocyanate, xylylene diisocyanate, methylcyclohexyl diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate dimer, hexamethylene diisocyanate trimer, hexamethylene diisocyanate prepolymer, hexamethylene diisocyanate biuret, isophorone diisocyanate dimer, isophorone diisocyanate trimer, and diphenylmethane diisocyanate prepolymer.

8. The organic-inorganic hybrid sustained-release flavor microcapsule according to claim 7, characterized in that: The emulsifier includes one or more of polyvinyl alcohol, polyvinyl pyrrolidone, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, pectin, gum arabic, gelatin, Tween 80, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, phosphate, sodium polyacrylate, sodium carboxymethyl cellulose, dodecyl ammonium chloride, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, styrene maleic anhydride copolymer, polyacrylamide, dimethyl diallyl ammonium chloride homopolymer, acrylamide, diallyldimethylammonium chloride copolymer, and ethoxylated alkyl sodium sulfate.

9. A method for preparing the organic-inorganic hybrid sustained-release flavor microcapsule according to any one of claims 1 to 8, comprising the following steps: A silane precursor and a silane coupling agent are mixed, and pre-hydrolyzed with 15% to 25% by weight of deionized water to obtain a mixed solution; The polyisocyanate and the essential oil are stirred and mixed to form an oil phase, 20% to 30% by weight of deionized water is used to stir and dissolve the emulsifier to form a first aqueous phase, and the remaining deionized water is used to stir and dissolve the polyamine compound to form a second aqueous phase; The oil phase is added to the mixed solution, and then the first water phase is added, homogenized and emulsified to form an emulsion, and the second water phase is added dropwise to the emulsion, and the temperature is raised to react to obtain a microcapsule suspension containing essential oil; After the reaction is completed, the product is cooled, washed with water, filtered and dried to obtain the essence microcapsules.

10. The method for preparing the organic-inorganic hybrid sustained-release flavor microcapsules according to claim 9, characterized in that: The heating includes heating in steps, specifically including: the initial temperature is 20-35°C, each heating is 8-12°C, and the temperature is kept for 0.75-1.5h until the temperature reaches 50-70°C.

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