Preparation method and application of beta-cyclodextrin-polyurethane double-shell microcapsule

Abstract

The invention discloses a preparation method and application of a beta-cyclodextrin-polyurethane double-shell microcapsule, and the preparation method comprises the following steps: taking polyurethane and beta-cyclodextrin as wall materials, introducing an epoxy group into a shell material, taking plant essential oil as a core material, and preparing the double-shell microcapsule through an interfacial polymerization method; furthermore, the microcapsules are applied to the cotton fabric through an impregnation process, so that the functional textile with dual functions of odor adsorption and essence slow release is prepared, the fresh odor retention time of the textile is prolonged, and the odor is effectively removed. The beta-cyclodextrin-polyurethane double-shell microcapsule prepared by the invention can be applied to the fields of home textiles, curtain fabrics, sportswear, leather and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical material preparation, and specifically relates to a preparation method and application of a beta-cyclodextrin-polyurethane double-shell microcapsule. Background Art

[0002] With the improvement of living standards, people's demand for the functionality of textiles is growing. Although traditional textiles can meet basic wearing comfort, they have obvious limitations in dealing with odor, antibacterial and health care. The odor problem is particularly prominent in wearable textiles, interior decoration and medical fields. Long-term odor accumulation not only affects the user experience, but may also cause health problems. Therefore, the development of textiles with odor absorption and slow-release fragrance functions is particularly important and has significant practical significance.

[0003] Cyclodextrins are oligosaccharide compounds produced by the degradation of starch by cyclodextrin glucosyltransferase in Bacillus. There are three structures: α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin. β-cyclodextrin (β-CD) is a widely used, cost-effective green natural product with a moderate molecular pore size. The entire molecule has a hydrophobic inner cavity and a hydrophilic outer surface. β-cyclodextrin can selectively form complexes with guest molecules that match the cavity size through weak interactions such as hydrophobicity, hydrogen bonding and van der Waals forces. Due to its natural origin, cyclodextrins have excellent biocompatibility compared with chemically synthesized organic compounds. They also exhibit host-guest adsorption properties, which make them widely used in textiles, food and agriculture. However, the single functional group in the β-cyclodextrin molecule limits the scope of chemical reactions. In previous studies, several methods have been proposed to modify β-cyclodextrin, increase the number of its active functional groups, and expand the application range of β-cyclodextrin.

[0004] In the prior art, a Chinese invention patent (application number: CN201911235816.1) provides a catnip essential oil / naphthoylated β-cyclodextrin microcapsule and a preparation method thereof. The microcapsule uses catnip essential oil as a core material and naphthoylated β-cyclodextrin as a wall material. At a certain temperature, the microcapsule can control the release rate and uniformity of catnip essential oil, thereby solving the problem of controllable release rate of the embedded catnip essential oil. However, the preparation method is relatively complicated, and it is not a double shell, so the essential oil is easy to leak. A Chinese invention patent (application number: CN202110814410.X) provides a flavor microcapsule prepared by spray drying technology using hydroxypropyl-β-cyclodextrin and mannitol as wall materials and lavender essence as a core material. The prepared lavender essence microcapsule has a sea urchin-like morphology, a rough surface, and low hygroscopicity and a high dissolution rate. However, the microcapsules prepared by this method have poor sealing properties and the core material is prone to leakage. At the same time, the host-guest adsorption effect of cyclodextrin is not utilized in the application process of microcapsules. Summary of the invention

[0005] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0006] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0007] Therefore, the purpose of the present invention is to overcome the deficiencies in the prior art and provide a β-cyclodextrin-polyurethane double-shell microcapsule.

[0008] To solve the above technical problems, the present invention provides the following technical solution: a β-cyclodextrin-polyurethane double-shell microcapsule, characterized in that: the microcapsule is a core-shell structure, wherein the core material is plant essential oil, the inner wall material is polyurethane, and the outer shell material is modified β-cyclodextrin.

[0009] As a preferred embodiment of the β-cyclodextrin-polyurethane double-shell microcapsule of the present invention, the plant essential oil includes one or more of lemon essential oil, peppermint essential oil, jasmine essential oil, gardenia essential oil and lavender essential oil.

[0010] Another object of the present invention is to overcome the deficiencies in the prior art and provide a method for preparing β-cyclodextrin-polyurethane double-shell microcapsules.

[0011] In order to solve the above technical problems, the present invention provides the following technical solutions: comprising:

[0012] β-cyclodextrin, anhydrous N,N-dimethylformamide-anhydrous dimethyl sulfoxide mixture, sodium hydroxide, and bromoolefin are mixed and centrifuged, and the obtained precipitate is washed with acetone, filtered, and dried to obtain modified β-cyclodextrin;

[0013] The mercapto-modified glycidyl methacrylate is obtained by mixing 3-mercapto-1,2-propylene glycol, glycidyl methacrylate, acetone, and diphenylphosphine;

[0014] Dissolve isophorone diisocyanate, acetone, dibutyltin dilaurate, 1,4-butanediol, 3-mercapto-1,2-propylene glycol, and the above-mentioned mercapto-modified glycidyl methacrylate, mix and react, and remove acetone by rotary evaporation to obtain the obtained product to obtain a polyurethane prepolymer;

[0015] The emulsifier is dissolved in deionized water to form a water phase; the polyurethane prepolymer, polyethylene glycol and plant essential oil are evenly mixed by ultrasonication to form an oil phase; the mixed oil phase is added to the water phase, and a stable oil-in-water emulsion is formed after ultrasonic emulsification;

[0016] The modified β-cyclodextrin is dissolved in deionized water, and diphenylphosphine is dissolved in ethanol and mixed with the above-mentioned oil-in-water emulsion to obtain polyurethane microcapsules.

[0017] As a preferred embodiment of the preparation method of the present invention, the mass ratio of the β-cyclodextrin, the anhydrous N,N-dimethylformamide-anhydrous dimethyl sulfoxide mixture, sodium hydroxide and the brominated olefin is 1-5:20-50:3-5:5-10.

[0018] As a preferred embodiment of the preparation method of the present invention, the brominated olefins include one or more of brominated propylene, brominated butylene, brominated amylene and brominated hexylene; and the emulsifier is one or more of sodium dodecylbenzene sulfonate, polyoxyethylene sorbitan monooleate, sodium lauryl sulfate, polyoxyethylene-8-octylphenyl ether, polyoxyethylene sorbitan monolaurate, sorbitan fatty acid esters and polyvinyl alcohol.

[0019] As a preferred embodiment of the preparation method of the present invention, the mass ratio of 3-mercapto-1,2-propylene glycol, glycidyl methacrylate, acetone and diphenylphosphine is 1-5:1-5:1.5-6:20-50:0.1-0.5.

[0020] As a preferred embodiment of the preparation method of the present invention, the mass ratio of isophorone diisocyanate, acetone, dibutyltin dilaurate, 1,4-butanediol, 3-mercapto-1,2-propylene glycol and mercapto-modified glycidyl methacrylate is 10-20:20-60:0.1-0.4:0.5-2:0.1-0.7:0.5-2.

[0021] As a preferred embodiment of the preparation method of the present invention, the mass ratio of sodium dodecylbenzene sulfonate to deionized water in the aqueous phase is 0.1-0.5:60-150; the mass ratio of polyurethane prepolymer, polyethylene glycol and plant essential oil in the oil phase is 2-6:2-5:1-6.

[0022] As a preferred embodiment of the preparation method of the present invention, the invention is characterized in that the mass ratio of the modified β-cyclodextrin, deionized water, diphenylphosphine and ethanol is 1.5-6:10-50:0.05-0.2:1-5.

[0023] Another object of the present invention is to overcome the deficiencies in the prior art and provide a β-cyclodextrin-polyurethane double-shell microcapsule for use in textiles.

[0024] The polyurethane microcapsules are dispersed in deionized water to obtain microcapsule dispersion liquid; pure cotton fabric is immersed in the dispersion liquid and then dried to obtain cotton fabric finished with beta-cyclodextrin-polyurethane double-shell microcapsules.

[0025] Beneficial effects of the present invention:

[0026] The prepared β-cyclodextrin-polyurethane double-shell microcapsules not only have the dual functions of absorbing odor, but also releasing fragrance and covering odor, and can effectively synergistically cover and remove "senile odor"; the double-shell structure design can increase the airtightness of the shell, so that the core material is not easy to leak, and finally the service life of the microcapsules can be extended; the epoxy groups introduced into the shell material of the microcapsule can increase the covalent bond between the microcapsule and the fabric, so as to improve its fastness on the fabric; the β-cyclodextrin / polyurethane double-shell microcapsules can be used in application fields such as home textiles, health textiles, sportswear, home decoration, and leather products. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0028] Figure 1 The structural representation diagram of the modified cyclodextrin of the present invention. Figure 1 (a) is the infrared spectra of β-CD and allyl β-CD; Figure 1 (b) is the H NMR spectrum of β-CD. Figure 1 (c) is the H NMR spectrum of allyl β-CD.

[0029] Figure 2 The SEM image and EDS spectrum of the microcapsule of the present invention are shown in FIG. Figure 2 (a) is the SEM image of polyurethane microcapsules; Figure 2 (bd) are SEM images of β-CD-polyurethane double-shell microcapsules; Figure 2 (e) is the particle size distribution histogram of polyurethane microcapsules; Figure 2 (f) is the particle size distribution histogram of β-CD / polyurethane double-shell microcapsules; Figure 2 (g) is the EDS spectrum and element distribution spectrum of β-CD / polyurethane double-shell microcapsules.

[0030] Figure 3 The infrared spectrum and thermogravimetric analysis diagram of the microcapsule of the present invention are shown in FIG. Figure 3 (a) is the infrared spectra of polyurethane prepolymer and β-CD / polyurethane double-shell microcapsules; Figure 3 (b) is the thermogravimetric analysis curve of peppermint essential oil, blank microcapsules and β-CD / polyurethane double-shell microcapsules; Figure 3 (c) is the differential thermogravimetric curve of peppermint essential oil and β-CD / polyurethane double-shell microcapsules.

[0031] Figure 4 The SEM images and EDS spectra of cotton fabrics before and after finishing with microcapsules of the present invention are shown in FIG. Figure 4 (a) is the cold field emission scanning electron microscope image of the original cotton fabric; Figure 4 (b, c) are cold field emission scanning electron microscopy images of cotton fabrics treated with β-CD / polyurethane double-shell microcapsules; Figure 4 (d) is the EDS spectrum and element distribution map of cotton fabric after finishing with β-CD / polyurethane double-shell microcapsules.

[0032] Figure 5 This is a test of the adsorption performance of the microcapsule-finished fabric of the present invention. Figure 5 (a) Odor adsorption mechanism of β-CD / polyurethane double-shell microcapsules; Figure 5 (b) is the standard absorbance-concentration curve of citral; Figure 5 (c) The adsorption performance of treated cotton fabric and blank cotton fabric on citral; Figure 5 (d) shows the adsorption performance of citral on cotton fabric before and after microcapsule treatment with β-CD; Figure 5 (e) is the standard absorbance-concentration curve of trans-2-nonenal; Figure 5 (f) is the adsorption performance of treated cotton fabric and blank cotton fabric on trans-2-nonenal; Figure 5 (g) shows the adsorption performance of trans-2-nonenal on cotton fabric treated with microcapsules before and after β-CD modification.

[0033] Figure 6 The cyclic adsorption performance and washing fastness of the fabric treated with microcapsules of the present invention. Figure 6 (a) is the cyclic adsorption curve of citral on treated cotton fabric; Figure 6 (b) is the cyclic adsorption curve of trans-2-nonenal on the treated cotton fabric; Figure 6 (c) is the adsorption curve of citral on cotton fabric before and after washing; Figure 6 (d) is the adsorption curve of trans-2-nonenal on cotton fabric before and after washing.

[0034] Figure 7 This is a test of the antibacterial properties of the fabric finished with the microcapsules of the present invention. Figure 7 (a) is the antibacterial mechanism diagram of β-CD / polyurethane double-shell microcapsules; Figure 7 (b) Growth images of Staphylococcus aureus and Escherichia coli on different sample surfaces; Figure 7 (c) is the bacterial inhibition rate diagram after different sample treatments; Figure 7 (d) is an image of Staphylococcus aureus and Escherichia coli growing on different sample surfaces; Figure 7 (e) is a graph showing the bacterial inhibition rate of different samples after treatment and for different days. DETAILED DESCRIPTION

[0035] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0036] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0037] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0038] Unless otherwise specified, all raw materials used in the examples of the present invention are commercially available, as shown in Table 1 for details.

[0039] Table 1

[0040]

[0041]

[0042] Example 1

[0043] (1) Add 1 part of β-cyclodextrin and 20 parts of anhydrous N,N-dimethylformamide / anhydrous dimethyl sulfoxide (volume ratio 1:1) into a beaker. After fully dissolving, add 3 parts of sodium hydroxide and stir at room temperature for 1 hour. Then, let the system cool naturally to 5°C, use a dropping funnel to slowly add 5 parts of bromobutylene into the system twice while stirring, and stir vigorously for 24 hours. After the reaction is completed, centrifuge, wash the precipitate with acetone for several times, filter, and dry to obtain modified β-cyclodextrin.

[0044] (2) 1 part of 3-mercapto-1-yl, 1 part of 2-propylene glycol, 1.5 parts of glycidyl methacrylate and 20 parts of acetone were placed in a three-necked flask, and ultrasonically mixed to make them uniform. 0.1 part of diphenylphosphine was added, and the mixture was reacted at 40° C. for 3-7 hours to obtain the product, mercapto-modified glycidyl methacrylate, which was set aside.

[0045] (3) 10 parts of isophorone diisocyanate and 20 parts of acetone were ultrasonically dissolved and mixed uniformly in a three-necked flask, 0.1 parts of dibutyltin dilaurate were added, and the mixture was preheated in an oil bath at 65°C; 0.5 parts of 1,4-butanediol, 0.1 parts of 3-mercapto-1, 0.1 parts of 2-propylene glycol, and 0.5 parts of the above-mentioned mercapto-modified glycidyl methacrylate were further dissolved and mixed and added to the three-necked flask, and the reaction was continued for 2 hours. The obtained product was rotary evaporated to remove acetone to obtain a polyurethane prepolymer.

[0046] (4) Take 0.1 parts of polyoxyethylene sorbitan monooleate and dissolve it in 60 parts of deionized water to form an aqueous phase; put 2 parts of polyurethane prepolymer, 2 parts of polyethylene glycol, and 1 part of gardenia essential oil in a beaker and mix them evenly by ultrasonication to form an oil phase, add the mixed oil phase into the aqueous phase, and form a stable water-in-oil emulsion after ultrasonic emulsification. Transfer the emulsion to a three-necked flask and stir evenly. Then take 1.5 parts of modified β-cyclodextrin and dissolve it in 10 parts of deionized water, and 0.05 parts of diphenylphosphine and dissolve it in 1 part of ethanol, and add them dropwise to the preheated three-necked flask, heat it to 50°C and react for 3 hours to obtain β-cyclodextrin-polyurethane double-shell microcapsules.

[0047] (5) Take 0.2 g of the prepared β-cyclodextrin-polyurethane double-shell microcapsules and disperse them in 20 parts of deionized water to obtain a microcapsule dispersion; immerse pure cotton fabric (5 cm×5 cm) in the dispersion for 10 min and dry it at 50°C to obtain cotton fabric treated with β-cyclodextrin-polyurethane double-shell microcapsules.

[0048] Example 2

[0049] (1) 4 parts of β-cyclodextrin and 45 parts of anhydrous N,N-dimethylformamide / anhydrous dimethyl sulfoxide (volume ratio 1:1) were added to a beaker. After fully dissolved, 4 parts of sodium hydroxide were added thereto and stirred at room temperature for 2.5 hours. Then the system was naturally cooled to 8°C, and 5.7 mL of bromoheptene was slowly added to the system twice with a dropping funnel while stirring. The reaction was vigorously stirred for 40 hours. After the reaction was completed, the precipitate was centrifuged and washed with acetone for several times, filtered, and dried to obtain modified β-cyclodextrin.

[0050] (2) 4 parts of 3-mercapto-1-yl, 4 parts of 2-propylene glycol, 5 parts of glycidyl methacrylate and 40 parts of acetone were placed in a three-necked flask, and ultrasonically mixed to make them uniform. 0.4 parts of diphenylphosphine were added, and the mixture was reacted at 70° C. for 6 h to obtain the product, mercapto-modified glycidyl methacrylate, which was set aside.

[0051] (3) 18 parts of isophorone diisocyanate and 50 parts of acetone were ultrasonically dissolved and mixed in a three-necked flask, 0.35 parts of dibutyltin dilaurate were added, and the mixture was preheated in an oil bath at 80°C; 1.8 parts of 1,4-butanediol, 0.6 parts of 3-mercapto-1, 0.6 parts of 2-propylene glycol, and 1.8 parts of the above-mentioned mercapto-modified glycidyl methacrylate were further dissolved and mixed and added to the three-necked flask, and the reaction was continued for 4.5 hours. The obtained product was rotary evaporated to remove acetone to obtain a polyurethane prepolymer.

[0052] (4) Take 0.4 parts of sodium dodecyl sulfate and dissolve it in 120 parts of deionized water to form an aqueous phase; put 5 parts of prepolymer, 4 parts of polyethylene glycol, and 5 parts of lavender essential oil in a beaker and mix them evenly by ultrasonication to form an oil phase, add the mixed oil phase into the aqueous phase, and form a stable water-in-oil emulsion after ultrasonic emulsification. Transfer the emulsion to a three-necked flask and stir evenly. Then take 5 parts of modified β-cyclodextrin and dissolve it in 40 parts of deionized water, and 0.15 parts of diphenylphosphine and dissolve it in 4 parts of ethanol, and add them dropwise to the preheated three-necked flask, heat it to 70°C and react for 5 hours to obtain β-cyclodextrin-polyurethane double-shell microcapsules.

[0053] (5) Disperse 0.8 g of the prepared β-cyclodextrin-polyurethane double-shell microcapsules in 40 parts of deionized water to obtain a microcapsule dispersion. Immerse pure cotton fabric (5 cm×5 cm) in the dispersion for 30 min and dry at 70°C to obtain cotton fabric treated with β-cyclodextrin-polyurethane double-shell microcapsules.

[0054] Example 3

[0055] (1) Add 5 parts of β-cyclodextrin and 50 parts of anhydrous N,N-dimethylformamide / anhydrous dimethyl sulfoxide (volume ratio 1:1) into a beaker. After fully dissolving, add 5 parts of sodium hydroxide and stir at room temperature for 3 hours. Then, let the system cool naturally to 10°C, use a dropping funnel to slowly add 10 parts of bromohexene into the system twice while stirring, and stir vigorously for 48 hours. After the reaction is completed, centrifuge, wash the precipitate with acetone for several times, filter, and dry to obtain modified β-cyclodextrin.

[0056] (2) 5 parts of 3-mercapto-1-yl, 5 parts of 2-propylene glycol, 6 parts of glycidyl methacrylate and 50 parts of acetone were placed in a three-necked flask, and ultrasonically mixed to make them uniform. 0.5 parts of diphenylphosphine were added, and the mixture was reacted at 80° C. for 7 h to obtain the product, mercapto-modified glycidyl methacrylate, which was set aside.

[0057] (3) 20 parts of isophorone diisocyanate and 60 parts of acetone were ultrasonically dissolved and mixed uniformly in a three-necked flask, 0.4 parts of dibutyltin dilaurate were added, and the mixture was preheated in an oil bath at 85°C; 2 parts of 1,4-butanediol, 0.7 parts of 3-mercapto-1, 0.7 parts of 2-propylene glycol, and 2 parts of the above-mentioned mercapto-modified glycidyl methacrylate were further dissolved and mixed and added to the three-necked flask, and the reaction was continued for 5 hours. The obtained product was rotary evaporated to remove acetone to obtain a polyurethane prepolymer.

[0058] (4) Take 0.5 parts of polyoxyethylene-8-octylphenyl ether and dissolve it in 150 parts of deionized water to form an aqueous phase; put 6 parts of prepolymer, 5 parts of polyethylene glycol, and 6 parts of jasmine essential oil in a beaker and mix them evenly by ultrasonication to form an oil phase, add the mixed oil phase into the aqueous phase, and form a stable oil-in-water emulsion after ultrasonic emulsification. Transfer the emulsion to a three-necked flask and stir evenly. Then take 6 parts of modified β-cyclodextrin and dissolve it in 50 parts of deionized water, and 0.2 parts of diphenylphosphine and dissolve it in 5 parts of ethanol, and add them dropwise to the preheated three-necked flask, and heat it to 80°C for 6 hours to obtain β-cyclodextrin-polyurethane double-shell microcapsules.

[0059] (5) Disperse 1 g of the prepared β-cyclodextrin-polyurethane double-shell microcapsules in 50 parts of deionized water to obtain a microcapsule dispersion. Immerse pure cotton fabric (5 cm×5 cm) in the dispersion for 30 min and dry at 80°C to obtain cotton fabric treated with β-cyclodextrin-polyurethane double-shell microcapsules.

[0060] Example 4

[0061] (1) 3 parts of β-cyclodextrin and 35 parts of anhydrous N,N-dimethylformamide / anhydrous dimethyl sulfoxide (volume ratio 1:1) were added to a beaker. After fully dissolved, 4 parts of sodium hydroxide were added thereto and stirred at room temperature for 2 hours. Then the system was naturally cooled to 7°C, and 7 parts of bromopentene were slowly added to the system in two portions using a dropping funnel while stirring. The reaction was vigorously stirred for 36 hours. After the reaction was completed, the precipitate was centrifuged and washed with acetone for several times, filtered, and dried to obtain modified β-cyclodextrin.

[0062] (2) 3 parts of 3-mercapto-1-yl, 3 parts of 2-propylene glycol, 3 parts of glycidyl methacrylate and 35 parts of acetone were placed in a three-necked flask, and ultrasonically mixed to make them uniform. 0.3 parts of diphenylphosphine were added, and the mixture was reacted at 60° C. for 5 h to obtain the product, mercapto-modified glycidyl methacrylate, which was set aside.

[0063] (3) 15 parts of isophorone diisocyanate and 40 parts of acetone were ultrasonically dissolved and mixed in a three-necked flask, 0.3 parts of dibutyltin dilaurate were added, and the mixture was preheated in an oil bath at 75°C; 1.3 parts of 1,4-butanediol, 0.4 parts of 3-mercapto-1, 0.4 parts of 2-propylene glycol, and 1.2 parts of the above-mentioned mercapto-modified glycidyl methacrylate were dissolved, mixed, and added to the three-necked flask, and the reaction was continued for 3 hours. The obtained product was rotary evaporated to remove acetone to obtain a polyurethane prepolymer.

[0064] (4) Take 0.3 parts of polyoxyethylene sorbitan monolaurate and dissolve it in 100 parts of deionized water to form an aqueous phase; put 4 parts of prepolymer, 4 parts of polyethylene glycol, and 4 parts of lemon essential oil in a beaker and mix them evenly by ultrasonication to form an oil phase, add the mixed oil phase into the aqueous phase, and form a stable water-in-oil emulsion after ultrasonic emulsification. Transfer the emulsion to a three-necked flask and stir evenly. Then take 4 parts of modified β-cyclodextrin and dissolve it in 30 parts of deionized water, and 0.1 parts of diphenylphosphine and dissolve it in 3 parts of ethanol, and add them dropwise to the preheated three-necked flask, and heat it to 60°C for 4 hours to obtain β-cyclodextrin-polyurethane double-shell microcapsules.

[0065] (5) Disperse 0.6 g of the prepared β-cyclodextrin-polyurethane double-shell microcapsules in 35 parts of deionized water to obtain a microcapsule dispersion. Immerse pure cotton fabric (5 cm×5 cm) in the dispersion for 20 min and dry at 65°C to obtain cotton fabric treated with β-cyclodextrin-polyurethane double-shell microcapsules.

[0066] Example 5

[0067] (1) Add 1.5 parts of β-cyclodextrin and 25 parts of anhydrous N,N-dimethylformamide / anhydrous dimethyl sulfoxide (volume ratio 1:1) into a beaker. After fully dissolving, add 3.5 parts of sodium hydroxide and stir at room temperature for 1 hour. Then, let the system cool naturally to 5°C, use a dropping funnel to slowly add 6 parts of propylene bromide into the system twice while stirring, and stir vigorously for 24-48 hours. After the reaction is completed, centrifuge, wash the precipitate with acetone for several times, filter, and dry to obtain modified β-cyclodextrin.

[0068] (2) 2 parts of 3-mercapto-1-yl, 2 parts of 2-propylene glycol, 2 parts of glycidyl methacrylate and 25 parts of acetone were placed in a three-necked flask, and ultrasonically mixed to make them uniform. 0.2 parts of diphenylphosphine were added, and the mixture was reacted at 50° C. for 4 h to obtain the product, mercapto-modified glycidyl methacrylate, which was set aside.

[0069] (3) 12 parts of isophorone diisocyanate and 30 parts of acetone were ultrasonically dissolved and mixed in a three-necked flask, 0.15 parts of dibutyltin dilaurate were added, and the mixture was preheated in an oil bath at 70°C; 0.7 parts of 1,4-butanediol, 0.3 parts of 3-mercapto-1, 0.3 parts of 2-propylene glycol, and 0.8 parts of the above-mentioned mercapto-modified glycidyl methacrylate were dissolved, mixed, and added to the three-necked flask, and the reaction was continued for 3 hours. The obtained product was rotary evaporated to remove acetone to obtain a polyurethane prepolymer.

[0070] (4) Take 0.2 parts of sodium dodecylbenzene sulfonate and dissolve it in 80 parts of deionized water to form an aqueous phase; put 3 parts of prepolymer, 3 parts of polyethylene glycol, and 2 parts of peppermint essential oil in a beaker and mix them evenly by ultrasonication to form an oil phase, add the mixed oil phase into the aqueous phase, and form a stable water-in-oil emulsion after ultrasonic emulsification. Transfer the emulsion to a three-necked flask and stir evenly. Then take 2 parts of modified β-cyclodextrin and dissolve it in 20 parts of deionized water, and 0.1 parts of diphenylphosphine and dissolve it in 2 parts of ethanol, and add them dropwise to the preheated three-necked flask, heat it to 60°C and react for 3 hours to obtain β-cyclodextrin-polyurethane double-shell microcapsules.

[0071] (5) Disperse 0.4 g of the prepared β-cyclodextrin-polyurethane double-shell microcapsules in 30 parts of deionized water to obtain a microcapsule dispersion. Immerse pure cotton fabric (5 cm×5 cm) in the dispersion for 20 min and dry at 60°C to obtain cotton fabric treated with β-cyclodextrin-polyurethane double-shell microcapsules.

[0072] Comparative Example 1

[0073] The difference from Example 5 is that in step (4), 0.2 parts of sodium dodecylbenzene sulfonate is dissolved in 80 parts of deionized water to form an aqueous phase; 3 parts of prepolymer, 3 parts of polyethylene glycol, and 2 parts of peppermint essential oil are placed in a beaker and ultrasonically mixed to form an oil phase, and the mixed oil phase is added to the aqueous phase, and ultrasonic emulsification is performed to form a stable oil-in-water emulsion. The emulsion is transferred to a three-necked flask, stirred evenly, and heated to 60°C for reaction for 3 hours to obtain polyurethane microcapsules.

[0074] Comparative Example 2

[0075] 0.1 parts of β-cyclodextrin was dissolved in 30 parts of deionized water to obtain a cyclodextrin solution. Pure cotton fabric (5 cm×5 cm) was immersed in the solution for 20 minutes and dried at 60° C. to obtain a cotton fabric treated with β-cyclodextrin.

[0076] Comparative Example 3

[0077] The difference from Example 5 is that in steps (4) and (5),

[0078] (4) Dissolve 0.2 parts of sodium dodecylbenzene sulfonate in 80 parts of deionized water to form a water phase; put 3 parts of prepolymer, 3 parts of polyethylene glycol, and 2 parts of peppermint essential oil in a beaker and mix them evenly by ultrasonication to form an oil phase; add the mixed oil phase to the water phase and form a stable oil-in-water emulsion by ultrasonic emulsification. Transfer the emulsion to a three-necked flask, stir evenly, and heat to 60°C for reaction for 3 hours to obtain polyurethane microcapsules.

[0079] (5) Disperse 0.4 g of the prepared polyurethane microcapsules in 30 parts of deionized water to obtain a microcapsule dispersion. Immerse pure cotton fabric (5 cm×5 cm) in the dispersion for 20 min and dry at 60° C. to obtain cotton fabric treated with polyurethane microcapsules.

[0080] Figure 1 This is a characterization of the structure of the modified cyclodextrin prepared in Example 5. Figure 1 a It can be seen that since β-CD itself contains multiple -OH groups, at 3420 cm -1 The characteristic absorption peaks of -OH appear at 1380, 1140, 1040 cm -1 The absorption peaks of modified β-cyclodextrin are at 1620 cm -1 An asymmetric stretching vibration absorption peak of C=C appears nearby, while β-cyclodextrin itself does not show an absorption peak there.

[0081] In summary, the allyl group has been successfully bonded to the β-CD molecule, and the cavity structure of β-CD is retained in the target molecule. The purified sample was further analyzed by hydrogen nuclear magnetic resonance spectrum. The 1H NMR spectra of β-CD and modified β-CD are shown in Figure 1b, c. 5.34×10- 6 It is the unsubstituted C3-OH hydrogen proton peak on the β-CD glucose unit, which is a single peak; (4.40~4.41)×10 -6 It is the multiple peak obtained by the splitting of C6-H from C5-H on the β-CD glucose unit; (5.55~5.60)×10 -6 It is the doublet peak obtained by the splitting of C1-H by C2-H on the β-CD glucose unit; 3.77×10 -6 4.20×10 -6 , 3.71×10 -6 It is the proton peak of C2-H, C5-H, and C4-H on β-CD. Secondly, 3.99×10 -6 It is the proton peak of the methylene group -C7H2- on the allyl group. This peak is affected by the oxygen atom and split into a double peak by the proton on the adjacent double bond; 5.51×10 -6 It is the proton peak on -HC8=C-; (5.43~5.46)×10 -6 It is the proton peak on the terminal olefin =C9H2. In summary, the above two types of proton peaks can be judged in the H NMR spectrum of the substance, and thus allyl β-CD has been successfully synthesized.

[0082] Figure 2 a is a SEM image of a polyurethane microcapsule without 6-O-allyl-β-CD loading (Comparative Example 1), Figure 2 e is its particle size distribution histogram. The particle size of polyurethane microcapsules is mainly concentrated at 1.1 μm, and the surface is smooth. After modification with β-CD modified with propylene bromide, the surface of the microcapsules becomes rough and the diameter increases. Figure 2 As shown in bd, the morphology and structure of the polyurethane microcapsules are consistent, and the diameter is mainly around 1.9 μm, which can also be seen from Figure 2 f, indicating that 6-O-allyl-β-cyclodextrin was successfully grafted onto the surface of the microcapsules through the click reaction. In addition, the EDX spectrum of the microcapsules and the corresponding element mapping are shown in Figure 2 The surface chemical composition of the microcapsules contained 69.0% carbon (C), 13.1% nitrogen (N), 14.8% oxygen (O) and 3.0% sulfur (S), and the presence of S element confirmed that thioglycerol was successfully grafted onto the polyurethane shell.

[0083] like Figure 3 As shown in a, the functional groups of polyurethane prepolymer and microcapsules were analyzed by infrared spectrometer. The main absorption peak of polyurethane prepolymer is located at 1720cm -1 、2270cm -1 and 3450cm -1The absorption peaks at specific wavelengths represent the stretching vibration peaks of C=O, -NCO- and -NH- groups. -1 The absorption peak at 3400 cm-1 disappeared, which is due to the reaction of the isocyanate group -NCO in the polyurethane prepolymer with the hydroxyl group in the chain-extending polyol after the addition of the chain extender, resulting in the disappearance of the -NCO- absorption peak in the microcapsule shell. These results indicate that the polyurethane shell was successfully synthesized. In addition, compared with the prepolymer, the hydroxyl group introduced by the addition of cyclodextrin makes the microcapsules -1 The absorption peak nearby becomes significantly broader, further indicating that cyclodextrin has been successfully connected to the surface of polyurethane microcapsules. Figure 3 b and 3c show the TGA curves and DTG curves of peppermint essential oil, blank microcapsules without encapsulated peppermint essential oil, and β-cyclodextrin / polyurethane microcapsules. From the TGA curve of peppermint essential oil, it can be seen that its decomposition temperature is between 110-200°C, which corresponds to the weight loss curve of the microcapsule. The small amount of decomposition of the microcapsule before 100°C is attributed to the small amount of water present in it. The decomposition at 100-200°C mainly corresponds to the decomposition of peppermint essential oil, and it also shows that the peppermint essential oil has been encapsulated in the microcapsule. As the temperature rises, the microcapsule loses a lot of weight after 250°C and is basically stable after 400°C. The weight loss at this stage is mainly caused by the decomposition of the microcapsule polymer shell material. According to the thermal weight loss curves of the microcapsules and the blank microcapsules in the control group, it can be calculated that the coverage rate of the microcapsule for peppermint essential oil is 30.91%.

[0084] like Figure 4 a shows the unfinished cotton fabric, which has a smooth cylindrical appearance. In contrast, the surface of the cotton fabric treated with microcapsules becomes obviously rough ( Figure 4 b). When observed under a higher magnification lens, it can be clearly seen that a large number of polyurethane microcapsules are attached to the fibers ( Figure 4 c). EDX spectrum and corresponding element mapping of cotton fabric after microcapsule finishing. Figure 4 As shown in Figure d, it can be seen that the three elements of carbon (C), nitrogen (N), and oxygen (O) are evenly distributed on the fiber surface; in addition, it can be clearly seen that there is a small amount of sulfur (S) element distributed, which is a reflection of the presence of thioglycerol monomers introduced when synthesizing the microcapsule shell material. The above two points prove that the distribution of microcapsules on the fiber surface is uniform.

[0085] Figure 5 a shows the host-guest adsorption function of β-cyclodextrin loaded on the polyurethane microcapsule shell. Citral and trans-2-nonenal were used as research materials to study the odor adsorption performance of polyurethane microcapsules. First, the standard concentration curve of citral was measured by UV spectrophotometer, and the linear fitting results were obtained, such as Figure 5b. The standard equation obtained by linear fitting is shown in formula (1):

[0086] C = 1.90621A - 7.59367 Formula (1);

[0087] The citral adsorption of cotton fabrics treated with polyurethane microcapsules at room temperature was measured by UV spectrophotometer. Figure 5 c. Cotton fabric itself has a certain adsorption effect. After the cotton fabric is treated with polyurethane microcapsules modified with 10% β-CD in proportion to the shell material, its adsorption performance is significantly improved, but not to the expected extent. Therefore, the amount of cyclodextrin in the shell material is further increased to 25%, so that the adsorption of citral by the treated cotton fabric is significantly enhanced for a period of time.

[0088] Secondly, the standard concentration curve of trans-2-nonenal was measured using an ultraviolet spectrophotometer, and the linear fitting results were obtained as follows: Figure 5 d, the standard equation obtained by linear fitting is shown in formula (2):

[0089] C = 7.31629A - 31.48825 Formula (2);

[0090] The polyurethane microcapsules modified with cyclodextrin, which accounted for 25% of the shell material, were impregnated onto the surface of cotton fabrics, and the adsorption performance of cotton fabrics on trans-2-nonenal before and after treatment was investigated. The results are as follows: Figure 5 e. The adsorption rate of trans-2-nonenal on cotton fabric itself is very low, reaching only 7.87% after being placed at room temperature for 2 hours, while the cotton fabric treated with microcapsules can reach 58.048%, indicating that the material has an effective adsorption capacity for trans-2-nonenal. The above results show that microcapsules have good odor absorption performance when applied to fabrics.

[0091] also, Figure 5 Figures 5d and 5g show the adsorption properties of citral and trans-2-nonenal on cotton fabrics treated with microcapsules before and after β-CD modification. Although the amount of β-CD added in the experiment was the same, the adsorption properties of the functional cotton fabrics obtained were very different. This difference is mainly due to the fact that β-CD modified with allyl bromide increases the number of reactive sites in the prepolymer that can interact with thiol groups. In contrast, unmodified β-CD can only attach to the surface of polyurethane microcapsules through end-capping reactions, resulting in a limited amount of β-CD being incorporated into the shell. Therefore, its adsorption capacity is relatively low.

[0092] The adsorption performance of the regeneration cycle for citral and trans-2-nonenal was verified by adsorption-desorption experiments. Figure 6Figures 6a and 6b are the desorption and re-adsorption results of citral after heating the functional cotton fabric that had previously adsorbed citral and trans-2-nonenal. The re-adsorption results show that the fabric treated with β-CD / polyurethane microcapsules has cyclic adsorption capacity. In order to evaluate the recycling effect of functional cotton fabrics, a washing test was carried out. Figure 6 c and Figure 6 d shows the adsorption results of citral and trans-2-nonenal on the functional cotton fabric before and after the washing cycle. Although the washing process reduced the adsorption capacity of the fabric, it still showed excellent adsorption performance.

[0093] In order to evaluate the antibacterial properties of functional cotton fabrics, the antibacterial effects of functional cotton fabrics on Staphylococcus aureus and Escherichia coli were tested by oscillation method and colony counting method. Figure 7 a is the antibacterial mechanism of β-CD-polyurethane microcapsules. The antibacterial effect of microcapsule-treated cotton fabric mainly comes from the peppermint essential oil encapsulated in the microcapsules. The antibacterial properties of microcapsule-treated cotton fabric were investigated using microcapsule-treated cotton fabric (Example 5), β-CD solution (Comparative Example 2), untreated polyurethane microcapsule-treated cotton fabric (Comparative Example 3) and untreated cotton fabric as control groups.

[0094] The results of the antibacterial activity of the four groups of samples against the two bacteria are as follows Figure 7 b and 7c. The inhibition rate of peppermint essential oil against Staphylococcus aureus was 98.82%, and the inhibition rate against Escherichia coli was 98.24%. The inhibition rates of cotton fabrics treated with allyl-β-cyclodextrin solution against the two bacteria were 27.06% and 8.26%, respectively. The inhibition rate of cotton fabrics treated with ungrafted microcapsules was low. The inhibition rates of microcapsule functionalized cotton fabrics were 97.06% and 95.88%, respectively. The results showed that both allyl-β-cyclodextrin and peppermint essential oil had antibacterial effects. However, the antibacterial activity of cyclodextrin was relatively weak, and the main antibacterial effect of polyurethane microcapsules was attributed to the release of the core material PEO. The PEO encapsulation and sustained release effect of the microcapsules gives the treated fabrics sustained antibacterial properties. As shown Figure 7 As shown in Figure 1, the microcapsules still maintained a high antibacterial activity after 7 days of storage. However, the antibacterial properties of the samples directly treated with essential oils decreased significantly after 7 days. The fabric treated with microcapsules still maintained the antibacterial effect after 14 days, indicating the sustained release effect of the microcapsules on the core material PEO.

[0095] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the present invention.

Claims

1. A β-cyclodextrin-polyurethane double-shell microcapsule, characterized in that: The microcapsule is a core-shell structure, wherein the core material is plant essential oil, the inner wall material is polyurethane, and the outer shell material is modified β-cyclodextrin.

2. The β-cyclodextrin-polyurethane double-shell microcapsule according to claim 1, characterized in that: The plant essential oil includes one or more of lemon essential oil, peppermint essential oil, jasmine essential oil, gardenia essential oil and lavender essential oil.

3. The method for preparing the β-cyclodextrin-polyurethane double-shell microcapsule according to claim 1 or 2, characterized in that: include, β-cyclodextrin, anhydrous N,N-dimethylformamide-anhydrous dimethyl sulfoxide mixture, sodium hydroxide, and bromoolefin are mixed and centrifuged, and the obtained precipitate is washed with acetone, filtered, and dried to obtain modified β-cyclodextrin; The mercapto-modified glycidyl methacrylate is obtained by mixing 3-mercapto-1,2-propylene glycol, glycidyl methacrylate, acetone, and diphenylphosphine; Dissolve isophorone diisocyanate, acetone, dibutyltin dilaurate, 1,4-butanediol, 3-mercapto-1,2-propylene glycol, and the above-mentioned mercapto-modified glycidyl methacrylate, mix and react, and remove acetone by rotary evaporation to obtain the obtained product to obtain a polyurethane prepolymer; The emulsifier is dissolved in deionized water to form a water phase; the polyurethane prepolymer, polyethylene glycol and plant essential oil are evenly mixed by ultrasonication to form an oil phase; the mixed oil phase is added to the water phase, and a stable oil-in-water emulsion is formed after ultrasonic emulsification; The modified β-cyclodextrin is dissolved in deionized water, and diphenylphosphine is dissolved in ethanol and mixed with the above-mentioned oil-in-water emulsion to obtain polyurethane microcapsules.

4. The preparation method according to claim 3, characterized in that: The mass ratio of the beta-cyclodextrin, the anhydrous N,N-dimethylformamide-anhydrous dimethyl sulfoxide mixture, sodium hydroxide and brominated olefin is 1-5:20-50:3-5:5-10.

5. The preparation method according to claim 3, characterized in that: The brominated olefins include one or more of brominated propylene, brominated butylene, brominated amylene and brominated hexylene; the emulsifier is one or more of sodium dodecylbenzene sulfonate, polyoxyethylene sorbitan monooleate, sodium lauryl sulfate, polyoxyethylene-8-octylphenyl ether, polyoxyethylene sorbitan monolaurate, sorbitan fatty acid ester and polyvinyl alcohol.

6. The preparation method according to claim 3, characterized in that: The mass ratio of the 3-mercapto-1,2-propylene glycol, glycidyl methacrylate, acetone and diphenylphosphine is 1-5:1-5:1.5-6:20-50:0.1-0.

5.

7. The preparation method according to claim 3, characterized in that: The mass ratio of isophorone diisocyanate, acetone, dibutyltin dilaurate, 1,4-butanediol, 3-mercapto-1,2-propylene glycol and mercapto-modified glycidyl methacrylate is 10-20:20-60:0.1-0.4:0.5-2:0.1-0.7:0.5-2.

8. The preparation method according to claim 3, characterized in that: The mass ratio of sodium dodecylbenzene sulfonate to deionized water in the water phase is 0.1-0.5:60-150; the mass ratio of polyurethane prepolymer, polyethylene glycol and plant essential oil in the oil phase is 2-6:2-5:1-6.

9. The preparation method according to claim 3, characterized in that: The mass ratio of the modified beta-cyclodextrin, deionized water, diphenylphosphine and ethanol is 1.5-6:10-50:0.05-0.2:1-5.

10. Use of the β-cyclodextrin-polyurethane double-shell microcapsule in textiles as claimed in claim 1, characterized in that: The polyurethane microcapsules are dispersed in deionized water to obtain microcapsule dispersion liquid; pure cotton fabric is immersed in the dispersion liquid and then dried to obtain cotton fabric finished with beta-cyclodextrin-polyurethane double-shell microcapsules.

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