Preparation method and application of silicon-based biodegradable essence microcapsule

Abstract

The invention relates to a preparation method and application of a silicon-based biodegradable essence microcapsule, and the preparation method of the silicon-based biodegradable essence microcapsule comprises the following steps: S1, uniformly mixing oily essence and a silicon-based mesoporous material to obtain an oil phase; dissolving an emulsifier in water to obtain a water phase; s2, mixing the oil phase and the water phase, and homogenizing to obtain an emulsion; and S3, adding a diisocyanate compound and polypropylene carbonate into the emulsion, and carrying out a stirring reaction to obtain the silicon-based biodegradable essence microcapsule. A silicon-based mesoporous material is introduced in the process of preparing the essence microcapsule by taking polypropylene carbonate as a wall material, a synergistic wrapping system of the essence microcapsule is constructed, and the volatile essence is subjected to double-layer protection by utilizing a mode of combining physical adsorption and chemical crosslinking embedding, so that the fragrance retention time of the essence is prolonged, and the fragrance retention time of the essence is prolonged. Meanwhile, the embedding rate of the microcapsule can be effectively improved, and the application of the essence microcapsule in actual production can be promoted by combining the biodegradable characteristic of the polypropylene carbonate.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of essence technology, in particular to a preparation method and application of a silicon-based biodegradable essence microcapsule. BACKGROUND

[0002] Microcapsules are closed micro-containers with a core-shell structure, which are prepared by encapsulating core materials with natural or synthetic polymer materials as wall materials, and the particle size of the obtained microcapsules is usually several microns to several hundred microns. By physical, physical-chemical or chemical methods, the core material is coated to obtain a small particle with controlled or sustained release effect, which can maximize the protection of the core material from the external environment. Among them, the essence microcapsule technology as an effective essence release and protection means has wide application prospect in food, daily chemical, textile and other fields.

[0003] The preparation technology of microcapsules usually includes droplet method, phase separation method, interfacial polymerization method, in-situ polymerization method and co-precipitation method, and different preparation methods have their own unique advantages. The commercialized microcapsule products are mainly prepared by in-situ polymerization method and interfacial polymerization method, and the wall materials of such microcapsules are mainly polyurea and polyurethane materials. Such materials are not easy to degrade in the environment, which may cause secondary pollution, and have poor biocompatibility. Non-toxic, renewable, biocompatible and completely biodegradable polymer materials such as polylactic acid and polypropylene carbonate are widely used in packaging, mulching film, biomedical and other fields. Such biodegradable polymers also have certain application potential in microcapsule wall materials, but in practical application, they still face the following problems: the mechanical strength of single biodegradable polymer wall material is low, which easily leads to premature leakage of essence; in addition, the embedding rate of such biodegradable polymer materials for hydrophobic essence is limited, especially for low-boiling-point or small-molecule essence components, it is difficult to achieve long-lasting fragrance.

[0004] Therefore, there is an urgent need for a long-lasting fragrance and biodegradable essence microcapsule to promote its practical application in food, daily chemical and textile fields. SUMMARY

[0005] To solve the above problems, the present application provides a preparation method and application of a silicon-based biodegradable essence microcapsule. In the process of preparing the essence microcapsule with biodegradable green material polypropylene carbonate (PPC) as the wall material, a silicon-based mesoporous material is introduced to construct a synergistic wrapping system of the essence microcapsule. By combining physical adsorption and chemical cross-linking embedding, volatile essence is double-coated, which not only prolongs the fragrance retention time and improves the embedding rate of the microcapsule, but also reduces the pollution of the essence microcapsule to the environment due to the biodegradable characteristics of the PPC material, which is conducive to promoting the application of the essence microcapsule in practical production.

[0006] Specifically, the following technical solutions are provided:

[0007] The first aspect of the present application provides a preparation method of a silicon-based biodegradable fragrance microcapsule, comprising the following steps:

[0008] S1, uniformly mixing an oily fragrance and a silicon-based mesoporous material to obtain an oil phase;

[0009] dissolving an emulsifier in water to obtain an aqueous phase;

[0010] S2, mixing the oil phase and the aqueous phase to obtain an emulsion by homogenization;

[0011] S3, adding a diisocyanate compound and a polypropylene carbonate to the emulsion, stirring and reacting to obtain the silicon-based biodegradable fragrance microcapsule.

[0012] Based on the current commercial microcapsule products, most of which use polyurea and polyurethane materials as wall materials, such materials are not easily degradable in the environment, which may cause secondary pollution, and have poor biocompatibility; and the use of polylactic acid and PPC, which are completely biodegradable polymers with non-toxic, renewable and good biocompatibility, as wall materials for encapsulating fragrances still has the following problems: (1) low strength, which easily leads to premature leakage of fragrances; (2) limited embedding rate for hydrophobic fragrances, which is difficult to achieve long-lasting fragrance retention. To solve the above problems, the present application provides a preparation method of a silicon-based biodegradable fragrance microcapsule which can achieve long-lasting fragrance retention, that is, in the process of preparing fragrance microcapsules with biodegradable green material PPC as wall material, silicon-based mesoporous material is introduced to construct a synergistic wrapping system of fragrance microcapsules, which can effectively improve the embedding rate of microcapsules and improve the strength of microcapsules prepared with PPC as wall material, which is beneficial to expand the application field of such fragrance microcapsules. Specifically:

[0013] The oil-based essence is mixed with the silicon-based mesoporous material to obtain an oil phase. The silicon-based mesoporous material with a high specific surface area and a porous channel structure can adsorb the essence through physical actions such as hydrogen bonding and Van der Waals force. Then, the oil phase is mixed with an emulsifier aqueous solution (water phase) to form an emulsion through high-speed homogenization. Then, a diisocyanate compound and a polypropylene carbonate are added to the emulsion. The polypropylene carbonate and the diisocyanate compound are chemically crosslinked to form a crosslinked network, embedding the oil droplets containing the silicon-based mesoporous material in the polypropylene carbonate crosslinked layer. Meanwhile, a large number of ester groups contained in the polypropylene carbonate crosslinked layer can form hydrogen bonds with the silicon hydroxyl groups on the surface of the silicon-based mesoporous material, further enhancing the interfacial interaction, and obtaining a silicon-based biodegradable essence microcapsule with a stable structure. Based on the synergistic effect of the above-mentioned physical adsorption and chemical crosslinking embedding, the volatile essence is double-protected, and the embedding rate of the microcapsule can be effectively improved, thereby greatly prolonging the time of the essence to remain. At the same time, the introduction of the silicon-based mesoporous material effectively improves the strength of the microcapsule with PPC as the wall material, and in combination with the biodegradable characteristics of PPC, it is beneficial to the practical production and application of the essence microcapsule in different fields.

[0014] Further, in step S1, the silicon-based mesoporous material is mesoporous silica nanospheres; more preferably, the particle size of the mesoporous silica nanospheres is less than 100 nm. Using mesoporous silica nanospheres as carriers, on the one hand, the surface is rich in silicon hydroxyl groups, which can adsorb essence molecules through physical actions such as hydrogen bonding and Van der Waals force. Meanwhile, the mesoporous silica nanospheres have a large number of pore structures, and after the essence molecules enter the pores, they can be fixed through adsorption and capillary action, which can improve the loading capacity and slow-release effect. More preferably, mesoporous silica nanospheres with a particle size of less than 100 nm are used, which have a larger specific surface area and more pore structures. When the mesoporous pore size is small, capillary condensation of the essence liquid in the pores can further improve the loading capacity.

[0015] Further, in step S1, the mass ratio of the oil-based essence to the silicon-based mesoporous material is (20-40):1, for example, 20:1, 25:1, 30:1, 35:1, 40:1, etc., including but not limited to the mass ratios listed above.

[0016] Further, in step S1, the emulsifier is preferably polyvinyl alcohol and / or sodium alginate.

[0017] Further, in step S1, the mass fraction of the emulsifier in the water phase is 10%-20%, for example, 10%, 12%, 14%, 16%, 18%, 20%, etc., including but not limited to the mass fractions listed above.

[0018] Further, in step S2, the mass ratio of the oil phase and the water phase is (3-4):5, for example 3:5, 3.2:5, 3.5:5, 3.8:5, 4:5, etc., including but not limited to the mass ratios listed above.

[0019] Further, in step S3, the diisocyanate compound includes but is not limited to isophorone diisocyanate and / or toluene diisocyanate.

[0020] Further, in step S3, the molecular weight of the polypropylene carbonate is 1000-3000.

[0021] Further, in step S3, the mass ratio of the diisocyanate compound to the polypropylene carbonate is preferably (5-8):(1-3), for example 5:1, 6:1, 7:1, 8:1, 5:2, 6:2, 7:2, 8:2, 5:3, 6:3, 7:3, 8:3, etc., including but not limited to the mass ratios listed above.

[0022] Further, in step S3, the mass ratio of the polypropylene carbonate to the oily fragrance in the emulsion is 1:(15-20), for example 1:15, 1:16, 1:17, 1:18, 1:19, 1:20, etc., including but not limited to the mass ratios listed above.

[0023] Further, in step S3, the temperature of the stirring reaction is preferably 50-80℃, and the time is preferably 3-4h.

[0024] The second aspect of the present application provides a silicon-based biodegradable fragrance microcapsule prepared by the preparation method of the first aspect.

[0025] The third aspect of the present application provides an application of the silicon-based biodegradable fragrance microcapsule of the second aspect in food, daily chemicals, and textiles.

[0026] Compared with the prior art, the present application has the following beneficial effects:

[0027] 1. The present application provides a preparation method of a silicon-based biodegradable fragrance microcapsule, which introduces a silicon-based mesoporous material to construct a synergistic wrapping system of the fragrance microcapsule in the process of preparing the fragrance microcapsule with biodegradable green material PPC as the wall material; the preparation method is simple, efficient, and low in cost, and utilizes physical adsorption and chemical cross-linking embedding in combination to double-coat the volatile fragrance, which can effectively improve the embedding rate of the microcapsule and prolong the fragrance retention time.

[0028] 2. The silicon-based biodegradable fragrance microcapsule prepared by the method, taking the biodegradable material PPC as the wall material, can absorb and utilize industrial waste carbon dioxide, thereby reducing the emission of carbon dioxide to some extent, alleviating the greenhouse effect, and effectively avoiding the problems of non-degradability, environmental pollution and poor biocompatibility of the microcapsules prepared by using polyurea and polyurethane materials as the wall material; more importantly, the introduced silicon-based mesoporous material can compensate for the defects of low strength and low application stability of the microcapsules prepared by using PPC as a single wall material, and the introduction of the silicon-based mesoporous material into the preparation process of the PPC microcapsule not only helps to improve the embedding rate of the microcapsule, but also effectively prolongs the fragrance retention time by constructing a multiple release structure through the combination of physical dispersion and chemical cross-linking. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 A scanning electron microscope (SEM) image of the silicon-based biodegradable fragrance microcapsule prepared in Example 1;

[0030] Figure 2 A SEM image of the silicon-based biodegradable fragrance microcapsule prepared in Comparative Example 1. DETAILED DESCRIPTION

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. The statement "comprising" or "containing" means that the composition can include other components in addition to those recited. The statement "comprising" or "containing" can be replaced by the closed statement "consisting of" or "consisting essentially of".

[0032] The application will be further described with reference to the following specific examples and drawings, so that those skilled in the art can better understand and implement the application, but the examples are not intended to limit the application.

[0033] Example 1

[0034] This example relates to the preparation of a silicon-based biodegradable fragrance microcapsule, and the specific preparation process is as follows:

[0035] (1) Preparation of the oil phase: mix the oily fragrance (Chihua Ton Company, model Magnolia Snow Peach) and mesoporous silica nanospheres (particle size 50-100 nm) in a mass ratio of 40:1, and place them in a magnetic stirring device for thorough mixing and uniformity, as the oil phase.

[0036] Preparation of water phase: PVA was mixed with water at a mass ratio of 1:9, and heated in a water bath until the PVA was fully dissolved to obtain a PVA aqueous solution with a mass concentration of 10%, which was used as the water phase.

[0037] (2) Preparation of emulsion: the oil phase prepared in step (1) was added to the water phase, and the mass ratio of the oil phase to the water phase was 4:5. High-speed homogenization was performed at a speed of 8000 rpm / min for 10 min to obtain an emulsion.

[0038] (3) Preparation of microcapsules: an appropriate amount of isophorone diisocyanate and polypropylene carbonate was added to the emulsion prepared in step (2), and then placed in a water bath magnetic stirring device. Stirring was performed at 500 rpm for 3 h at 50°C to obtain silicon-based biodegradable fragrance microcapsules. The mass ratio of isophorone diisocyanate to polypropylene carbonate was 5:1, and the mass ratio of polypropylene carbonate to the oily fragrance in the emulsion was 1:15.

[0039] The SEM image of the silicon-based biodegradable fragrance microcapsules prepared in this example is shown in FIG. 1. As can be seen from the figure, the microcapsules with uniform particle size were successfully prepared. Figure 1

[0040] Example 2

[0041] This example relates to the preparation of silicon-based biodegradable fragrance microcapsules, and the specific preparation process is as follows:

[0042] (1) Preparation of oil phase: oily fragrance (Qiaohuadun Company, model: orchid snow pear) and mesoporous silica nanospheres (particle size: 50-100 nm) were mixed at a mass ratio of 20:1, and then placed in a magnetic stirring device for thorough mixing and uniformity, which was used as the oil phase.

[0043] Preparation of water phase: sodium alginate was mixed with water at a mass ratio of 1:9, and heated in a water bath until the sodium alginate was fully dissolved to obtain a sodium alginate aqueous solution with a mass concentration of 10%, which was used as the water phase.

[0044] (2) Preparation of emulsion: the oil phase prepared in step (1) was added to the water phase, and the mass ratio of the oil phase to the water phase was 3:5. High-speed homogenization was performed at a speed of 8000 rpm / min for 10 min to obtain an emulsion.

[0045] (3) Preparation of microcapsules: an appropriate amount of toluene diisocyanate and polypropylene carbonate was added to the emulsion prepared in step (2), and then placed in a water bath magnetic stirring device. Stirring was performed at 500 rpm for 3 h at 50°C to obtain silicon-based biodegradable fragrance microcapsules with uniform particle size. The mass ratio of toluene diisocyanate to polypropylene carbonate was 8:3, and the mass ratio of polypropylene carbonate to the oily fragrance in the emulsion was 1:18. ​

[0046] Comparative Example 1

[0047] This comparative example relates to the preparation of a silicon-based biodegradable fragrance microcapsule, the difference from Example 1 is only that an equal amount of polylactic acid is used to replace the polypropylene carbonate in Example 1, and the rest of the operations are consistent. The SEM image of the product prepared is shown in Figure 2 , which presents a foam porous morphology, and no microcapsule is obtained.

[0048] Comparative Example 2

[0049] This comparative example relates to the preparation of a degradable fragrance microcapsule, the difference from Example 1 is only that no mesoporous silica nanospheres are added, and the rest of the operations are consistent. The degradable fragrance microcapsule is prepared.

[0050] Comparative Example 3

[0051] This comparative example relates to the preparation of a carbon-based biodegradable fragrance microcapsule, the difference from Example 1 is only that an equal amount of porous carbon is used to replace the mesoporous silica nanospheres in Example 1, and the rest of the operations are consistent. The carbon-based biodegradable fragrance microcapsule is prepared.

[0052] Test Example

[0053] Taking Example 1 and Comparative Examples 2 and 3 as examples, the influence of the introduction of mesoporous silicon-based materials on the fragrance embedding rate and the fragrance retention effect is studied, and the test process is as follows:

[0054] (1) Fragrance embedding rate test: toluene is used as the solvent for extraction, and the embedding rate of the fragrance microcapsule is indirectly determined by measuring the concentration of the uncoated fragrance oil phase core material.

[0055] a. Drawing of standard curve

[0056] The full wavelength of the fragrance-toluene solution is scanned using a UV spectrophotometer to obtain the maximum absorption peak of the solution. Then a series of gradient concentration solutions of fragrance-toluene solution (10 mg / mL, 5 mg / mL, 2.5 mg / mL, 1.25 mg / mL, 0.625 mg / mL, 0.3125 mg / mL) are prepared using toluene as the solvent. Then under the maximum absorption peak, the absorbance of the six standard solutions is measured using a UV spectrophotometer, and the core material concentration is taken as the abscissa and the corresponding absorbance is taken as the ordinate. According to the measured data, a standard curve is fitted.

[0057] b. Determination of embedding rate

[0058] Take 1.5 g of the prepared fragrance microcapsule slurry and add it to 30 mL of toluene, and mix it slightly to extract the uncoated core material in the microcapsule slurry into the toluene solution. After standing, take the supernatant and measure its absorbance, or take 0.5 g of the supernatant and add it to 10 mL of toluene for secondary dilution, and then measure its absorbance. According to the measured absorbance and the standard curve equation, the uncoated fragrance concentration is calculated, and then the total amount of uncoated fragrance in the sample can be known.

[0059] The embedding rate of the core material = 1 - mFO / m x 100%, wherein mFO is the mass of the uncoated free fragrance in the sample; m is the total mass of the added fragrance.

[0060] (2) Fragrance retention effect test: The fragrance microcapsules were compounded with laundry detergent (the addition amount of microcapsules was 0.5%), and washing test was performed. The specific steps are as follows:

[0061] a. Respectively take 5 g of washing products and place them in small washing machines with the same washing capacity.

[0062] b. Add the same experimental fabric, add 1.5 kg of tap water, soak for 15 min, then start washing for 15 min, add 1.5 kg of tap water for cleaning for 3 min, and cycle for 3 times.

[0063] c. Place the washed fabric in separate drying rooms with the same environment and dry naturally.

[0064] d. Form a sensory evaluation team of 10 people to evaluate the washed and dried fabric, and test the fragrance retention effect of the washing product with added fragrance microcapsules. The sensory evaluation adopts a 5-point system, and the higher the score, the better the fragrance retention effect. The specific sensory evaluation characteristics and scoring standards are shown in the following table:

[0065]

[0066] The test results of the above fragrance embedding rate and fragrance retention effect are shown in Table 1 below:

[0067] Table 1

[0068]

[0069]

[0070] From Table 1, compared with the degradable fragrance microcapsules prepared without adding mesoporous silica-based materials in Comparative Example 2, the fragrance embedding rate of the silica-based biodegradable fragrance microcapsules prepared in Example 1 is significantly improved, and the fragrance retention effect is also improved. The fragrance microcapsules constructed by porous carbon and PPC in Comparative Example 3 have lower fragrance embedding rate and fragrance retention effect than those in Comparative Example 2, which is presumably due to the poor interfacial bonding force between porous carbon and PPC, resulting in the inability to form a stable structure of fragrance microcapsules, thereby reducing the fragrance embedding rate and fragrance retention effect.

[0071] The above-described examples are only preferred examples for fully illustrating the present application, and the protection scope of the present application is not limited thereto. Any equivalent replacement or transformation made by those skilled in the art on the basis of the present application is within the protection scope of the present application. The protection scope of the present application is subject to the claims.

Claims

1. A method for preparing silicon-based biodegradable flavor microcapsules, characterized in that: The following steps are involved: S1. Evenly mix the oily essence and the silicon-based mesoporous material to obtain an oil phase; dissolving an emulsifier in water to obtain an aqueous phase; S3, mixing the oil phase with the water phase and homogenizing to obtain an emulsion; S4. Adding a diisocyanate compound and polypropylene carbonate to the emulsion, stirring and reacting, to obtain the silicon-based biodegradable flavor microcapsules.

2. The preparation method according to claim 1, characterized in that In step S1, the silicon-based mesoporous material is mesoporous silica nanospheres; the particle size of the mesoporous silica nanospheres is less than 100 nm.

3. The preparation method according to claim 1 or 2, characterized in that In step S1, the mass ratio of the oily essence to the silicon-based mesoporous material is (20-40):

1.

4. The preparation method according to claim 1, characterized in that In step S1, the emulsifier is polyvinyl alcohol and / or sodium alginate; The mass proportion of the emulsifier in the aqueous phase is 10%-20%.

5. The preparation method according to claim 1, characterized in that In step S2, the mass ratio of the oil phase to the water phase is (3-4):

5.

6. The preparation method according to claim 1, characterized in that In step S3, the diisocyanate compound is isophorone diisocyanate and / or toluene diisocyanate; The molecular weight of the polypropylene carbonate is 1000-3000.

7. The preparation method according to claim 1 or 6, characterized in that In step S3, the mass ratio of the diisocyanate compound to the polypropylene carbonate is (5-8): (1-3); The mass ratio of the polypropylene carbonate to the oily essence in the emulsion is 1:(15-20).

8. The preparation method according to claim 1, characterized in that In step S3, the stirring reaction temperature is 50-80° C. and the time is 3-4 hours.

9. Silicon-based biodegradable flavor microcapsules prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the silicon-based biodegradable flavor microcapsule according to claim 9 in food, daily chemicals and textiles.

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