Frictional fragrance-releasing microcapsules and methods

Abstract

The application provides a frictional fragrance-releasing microcapsule and method, and the frictional fragrance-releasing microcapsule comprises the following components: a polyurea wall material, a fragrance, MCT, and an emulsifier; the polyurea wall material is an elastomer material generated by the reaction of isophorone diisocyanate and tetramethyl ethylenediamine, the system proportion of isophorone diisocyanate is (10-15) wt%, the system proportion of tetramethyl ethylenediamine is (1-2) wt%, and the frictional fragrance-releasing microcapsule is an eccentric asymmetric structure; the microcapsule obtained by the application can slowly release the fragrance, and still has a sustained fragrance-retaining effect under high-temperature conditions. Meanwhile, the microcapsule is broken by friction, the core material is released, the effect of frictional fragrance release is achieved, and the development of functional textile with fragrance is further promoted.

Description

Technical Field

[0001] This invention relates to a friction-released fragrance microcapsule and method, belonging to the field of natural polymers. Background Technology

[0002] Fragrances are volatile and easily oxidized, making them highly susceptible to deterioration during storage, transportation, and use. This leads to changes in aroma and flavor, significantly reducing their utilization efficiency. Currently, microencapsulation technology is the most effective method for encapsulating fragrances.

[0003] Polyurea systems are elastomeric polymers produced by the reaction of isocyanates and amino compounds. They possess excellent corrosion resistance, water resistance, and wear resistance, and are inexpensive and environmentally friendly, making them considered the optimal shell material for microcapsules. However, most microcapsules prepared using current technologies do not exhibit good high-temperature resistance, and the preparation process often results in the presence of toxic substances such as formaldehyde and glutaraldehyde, thus limiting their application in food, textiles, coatings, and composite materials.

[0004] With the continuous rise of the global economy and people's changing awareness of personal health and beauty, emerging specialty value-added textiles, such as aromatic textiles, are booming. Textile processing typically involves high-temperature treatments such as printing and drying; therefore, research on improving the slow-release properties and thermal stability of aromatic textiles is crucial. Furthermore, the friction between the fabric and the skin allows for the slow release of characteristic fragrances, enhancing the consumer's wearing experience. Friction-release aromatic fabrics not only improve the utilization efficiency of fragrance components but also enhance the consumer experience. Summary of the Invention

[0005] This invention provides a friction-release fragrance microcapsule and its method. The method employs interfacial polymerization technology, where isocyanate monomers and amine monomers undergo a polymerization reaction at the oil-water interface to form a polyurea wall material, thereby encapsulating the fragrance. The microcapsules prepared by this method possess properties such as friction-release fragrance, long-lasting fragrance, and high-temperature resistance. The preparation process is highly efficient, simple, and suitable for large-scale production.

[0006] To achieve this objective, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides a friction-releasing fragrance microcapsule comprising the following components: a polyurea wall material, a fragrance, MCT, and an emulsifier; wherein the polyurea wall material is an elastomer material generated by the reaction of isophorone diisocyanate and tetramethylethylenediamine, wherein the isophorone diisocyanate accounts for (10-15) wt% of the system and the tetramethylethylenediamine accounts for (1-2) wt% of the system; and wherein the friction-releasing fragrance microcapsule has an eccentric asymmetric structure.

[0008] Preferably, the fragrance system comprises (5-8) wt%.

[0009] Preferably, the MCT system accounts for (5-8) wt%.

[0010] Preferably, the emulsifier is polyvinyl alcohol.

[0011] Preferably, the degree of alcoholysis of the polyvinyl alcohol is 87-89%, the solution concentration is 10 wt%, and the system percentage is (10-12) wt%.

[0012] Preferably, the thickness of the polyurea wall material is 200-1000 nm. More preferably, the core-to-wall ratio of the friction-releasing fragrance microcapsules is 1:1.

[0013] In this invention, the fragrance includes, but is not limited to, one or more of rose fragrance, daylily fragrance, jasmine fragrance, or other fragrances, essential oils, perfumes, etc., containing volatile aromatic substances.

[0014] A second aspect of the present invention provides a method for preparing friction-releasing aroma microcapsules, comprising the following steps:

[0015] S1. Dissolve the emulsifier in deionized water to obtain aqueous phase A;

[0016] S2. Mix isophorone diisocyanate, fragrance and MCT in a certain proportion to obtain oil phase B;

[0017] S3. Slowly add oil phase B to aqueous phase A;

[0018] S4. A uniform oil-in-water emulsion is formed through high-speed shearing;

[0019] S5. Add the appropriate proportion of the initiator tetramethylethylenediamine to the oil-in-water emulsion obtained in S4, mix evenly, seal and transfer to an ultrasonic cleaner, react at a constant temperature in a water bath, and then raise the temperature to continue the reaction.

[0020] S6. Perform a heat preservation reaction to obtain a microcapsule suspension;

[0021] S7. Filter the microcapsule suspension described in S6 using two layers of gauze.

[0022] In this invention, in step S5, ultrasound-assisted interfacial polymerization accelerates the transfer rate of amine monomers to the organic phase, ensuring thorough mixing between the reactants and promoting the full progress of the interfacial polymerization reaction to form a highly cross-linked microcapsule wall material. Ultrasonic treatment is performed simultaneously with the curing of the microcapsule wall material. The vibration of the ultrasound waves causes continuous movement of molecules in the medium, which facilitates the formation of an eccentric, asymmetrical structure, resulting in uneven thickness of the microcapsule wall material and achieving a frictional release effect to control the release of fragrance. Furthermore, a large amount of foam is generated during the reaction; ultrasonic treatment also achieves degassing.

[0023] Preferably, the emulsifier is polyvinyl alcohol.

[0024] Preferably, the high-speed shearing conditions are 7500 rpm for 15 min.

[0025] Preferably, the conditions for the heat preservation reaction are: temperature 50-80℃, reaction time 4-10h.

[0026] In this invention, experiments have demonstrated that the diameter of the friction-releasing microcapsules can be controlled by the emulsification shear rate, and the microcapsule wall thickness can be controlled by the reaction temperature. Furthermore, the thickness of the microcapsule wall material has a significant impact on the friction-releasing effect; a wall thickness greater than 200 nm is required for a friction-releasing effect (the optimal reaction temperature is 80°C for 4 hours). When the wall material thickness is increased fivefold, the formed microcapsules are encapsulated and covered by excess wall material, resulting in no fragrance release effect.

[0027] Preferably, the preparation method of the friction-releasing aroma microcapsules includes the following steps:

[0028] Step 1: Preparation of the aqueous phase: Weigh a certain amount of polyvinyl alcohol and add it to water. Use a high-pressure homogenizer to shear at 3000 rpm for 10 seconds to ensure it is fully dissolved.

[0029] Step 2, Preparation of the oil phase: Weigh a certain amount of fragrance and dissolve it in MCT according to the ratio, and mix it with a certain amount of isophorone diisocyanate. Use a magnetic stirrer to stir and dissolve it thoroughly at a speed of 500 rpm for 10 min.

[0030] Step 3: Slowly add the oil phase obtained in Step 2 to the aqueous phase obtained in Step 1, and then shear the mixture at 7500 rpm for 15 min to obtain an oil-in-water emulsion.

[0031] Step 4: Incubate the oil-in-water emulsion at 60°C and 60 rpm for 5 minutes.

[0032] Step 5: Increase the rotation speed to 300 rpm and add tetramethylethylenediamine to the system to initiate the reaction.

[0033] Step 6: After mixing evenly, seal and transfer to an ultrasonic cleaner. Control the water bath temperature at 40-60℃ and react for 30 minutes to allow isophorone diisocyanate and tetramethylethylenediamine to fully polymerize.

[0034] Step 7: Raise the temperature of the system to 80℃ and react for 4 hours to solidify the microcapsule wall material.

[0035] Step 8: Filter the mixture through two layers of gauze to obtain a fragrance microcapsule suspension with polyurea as the wall material.

[0036] A third aspect of this invention provides an application of friction-releasing microcapsules in the textile field. The application method is as follows: the prepared polyurea microcapsule suspension is used as an immersion solvent for textile fabrics. After immersion for 1 minute, the fabric is dried in an oven at 180°C, and then the fragrance is released through friction.

[0037] Compared with the prior art, the beneficial effects and significant progress of applying the technical solution of the present invention are as follows:

[0038] 1. The present invention uses MCT and fragrance as composite core materials to prepare microcapsules. The addition of MCT is beneficial to the stability of the oil phase being embedded, forming a more stable interface film. As a result, when the microcapsules are used in textiles, they have a sustained release effect and good fragrance retention performance under high temperature conditions.

[0039] 2. The microcapsules prepared by this invention have a simple preparation process, require no complicated instruments and equipment, are green and pollution-free, and have high production efficiency, which can meet the needs of large-scale industrial production.

[0040] 3. This invention promotes the transfer rate of amine monomers to the organic phase through ultrasound-assisted interfacial polymerization, which enables thorough mixing between the reactants and thus promotes the full progress of the interfacial polymerization reaction, forming a highly cross-linked microcapsule wall material.

[0041] 4. Ultrasonic treatment is performed simultaneously with the curing of the microcapsule wall material. The vibration of the ultrasound waves causes continuous movement of molecules in the medium, which facilitates the formation of an eccentric, asymmetrical structure. This results in uneven thickness of the microcapsule wall material, achieving a frictional release effect and thus controlling the release of fragrance. Furthermore, a large amount of foam is generated during the reaction; ultrasonic treatment can also achieve degassing. Attached Figure Description

[0042] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the embodiments of the present invention will be briefly described below.

[0043] Figure 1 This is a scanning electron microscope image of the microcapsules of Example 1;

[0044] Figure 2The images shown are scanning electron microscope images of the microcapsules of Comparative Example 1. In Figure A, the reaction conditions were 80℃ for 4 h; in Figure B, the reaction conditions were 60℃ for 4 h; and in Figure C, the reaction conditions were 50℃ for 10 h.

[0045] Figure 3 The images shown are scanning electron microscope images of the microcapsules in Comparative Example 2. In Figure A, the reaction conditions were 60℃ for 4 h; in Figure B, the reaction conditions were 80℃ for 4 h.

[0046] Figure 4 This is a scanning electron microscope image of the microcapsules in Comparative Example 3. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the present invention is further described below in conjunction with specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or as recommended by the manufacturer. Unless otherwise stated, percentages and parts are weight percentages and parts by weight. Unless otherwise specified, the experimental materials and reagents used in the following embodiments are commercially available.

[0048] Unless otherwise specified, the 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 pertains. It should be noted that the terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the exemplary embodiments of this application.

[0049] Example 1

[0050] Experimental methods

[0051] 1.1 Preparation of Friction-Release Microcapsules

[0052] Step 1, Preparation of the aqueous phase: Add polyvinyl alcohol (10wt%-12wt%) to deionized water and use a high-pressure homogenizer at 3000rpm for 10s to fully dissolve it.

[0053] Step 2, Preparation of the oil phase: Dissolve the fragrance (5wt%-8wt%) in MCT (5wt%-8wt%) (fragrance:MCT=1:1), and mix it with (10-15)wt% of isophorone diisocyanate. Use a magnetic stirrer to stir and dissolve the mixture thoroughly at a speed of 500 rpm for 10 min.

[0054] Step 3: Slowly add the oil phase obtained in Step 2 to the aqueous phase obtained in Step 1, and then shear the mixture at 7500 rpm for 15 min to obtain an oil-in-water emulsion.

[0055] Step 4: Incubate the oil-in-water emulsion at 60°C and 60 rpm for 5 minutes.

[0056] Step 5: Increase the rotation speed to 300 rpm and add tetramethylethylenediamine (1 wt%-2 wt%) to the system to initiate the reaction.

[0057] Step 6: After mixing evenly, seal and transfer to an ultrasonic cleaner. Control the water bath temperature at 40-60℃ and react for 30 minutes to allow isophorone diisocyanate and tetramethylethylenediamine to fully polymerize.

[0058] Step 7: Raise the temperature of the system to 80℃ and react for 4 hours to solidify the microcapsule wall material.

[0059] Step 8: Filter the mixture through two layers of gauze to obtain a fragrance microcapsule suspension with polyurea as the wall material.

[0060] 1.2 Analysis of the thermal stability and aroma release properties of microcapsules

[0061] The prepared microcapsule suspension was used as a soaking solvent for textile fabrics. After soaking for 1 minute, the fabrics were dried in an oven at 180°C and then subjected to rubbing before being evaluated for their fragrance.

[0062] 1.3 Thickness of the microcapsule wall material

[0063] The measurements were performed using a scanning electron microscope.

[0064] Experimental results

[0065] like Figure 1 As shown, the thickness of the microcapsule wall material is 220-720nm, and the scented fabric, after being treated at high temperature, exhibits a significant fragrance release effect after friction.

[0066] The effect of process parameters of the heat preservation reaction on the thickness of the microcapsule wall material and the frictional fragrance release effect in Comparative Example 1

[0067] The difference between this comparative example and Example 1 is that the reaction conditions in step seven are adjusted to 60°C for 4 hours and 50°C for 10 hours.

[0068] Experimental results are as follows Figure 2 As shown, the thickness of the microcapsule wall material is 293.1-826.2 nm; the scented fabrics, after being treated at high temperature, all exhibit a significant fragrance release effect after friction.

[0069] The effect of process parameters of the insulation reaction under twice the wall material in Comparative Example 2 on the thickness of the microcapsule wall material and the frictional fragrance release effect.

[0070] The difference between this comparative example and Example 1 is that the proportion of wall material in Example 1 is increased to twice the amount, and the temperature in step seven is adjusted to 60°C.

[0071] Experimental results are as follows Figure 3 As shown, the thickness of the microcapsule wall material is 312.6-625.2 nm, the process parameters are 80℃, reaction time is 4 h, and the fragrance-added fabric is treated at high temperature, and the fragrance release effect is more obvious after friction.

[0072] Comparative Example 3

[0073] The difference between this comparative example and Example 1 is that the proportion of wall material in Example 1 is increased to five times, while everything else remains the same as in Example 1.

[0074] Experimental results are from Figure 4 It can be seen that the thickness of the microcapsule wall material is 1.197μm, and there is no fragrance release effect after friction. This indicates that the formed microcapsules are covered by excess wall material, which affects the fragrance release effect.

[0075] The applicant declares that, in the process of describing the above-mentioned specification:

[0076] The terms "this embodiment," "an embodiment of the present invention," "as shown," "further," and "further improved technical solutions," etc., indicate that the specific features, structures, materials, or characteristics described in the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms are not necessarily directed at the same embodiment or example, and the specific features, structures, materials, or characteristics described can be combined or combined in any suitable manner in one or more embodiments or examples. Furthermore, without causing contradiction, those skilled in the art can combine or combine the different embodiments or examples described in this specification and the features of the different embodiments or examples.

[0077] Finally, it should be noted that:

[0078] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them;

[0079] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention. Non-essential improvements, adjustments or substitutions made by those skilled in the art based on the content of this specification are all within the scope of protection claimed by the present invention.

Claims

1. A friction-release fragrance microcapsule, characterized in that, Includes the following components: polyurea wall material, fragrance, MCT, and emulsifier; The polyurea wall material is an elastomer material produced by the reaction of isophorone diisocyanate and tetramethylethylenediamine, wherein the isophorone diisocyanate accounts for (10-15) wt% of the system and the tetramethylethylenediamine accounts for (1-2) wt% of the system. Furthermore, the friction-releasing microcapsules have an eccentric asymmetric structure; the thickness of the polyurea wall material is 220-826.2 nm.

2. The friction-releasing fragrance microcapsule as described in claim 1, characterized in that, The fragrance system comprises (5-8) wt%.

3. The friction-releasing fragrance microcapsule as described in claim 1, characterized in that, The MCT system is described as having a proportion of (5-8) wt%.

4. The friction-releasing fragrance microcapsule as described in claim 1, characterized in that, The emulsifier is polyvinyl alcohol.

5. The friction-releasing aroma microcapsule as described in claim 4, characterized in that, The degree of alcoholysis of the polyvinyl alcohol is 87-89%, the solution concentration is 10wt%, and the system proportion is (10-12)wt%.

6. A method for preparing a friction-releasing aroma microcapsule, characterized in that, The preparation of the friction-releasing aroma microcapsules as described in any one of claims 1 to 5 comprises the following steps: S1. Dissolve the emulsifier in deionized water to obtain aqueous phase A; S2. Mix isophorone diisocyanate, fragrance and MCT in a certain proportion to obtain oil phase B; S3. Slowly add oil phase B to aqueous phase A; S4. A uniform oil-in-water emulsion is formed through high-speed shearing; S5. Add the appropriate proportion of initiator tetramethylethylenediamine to the oil-in-water emulsion obtained in S4, mix evenly, seal and transfer to an ultrasonic cleaner, react at a constant temperature in a water bath, and then raise the temperature to continue the reaction. S6. Perform a heat preservation reaction to obtain a microcapsule suspension; S7. Filter the microcapsule suspension described in S6 using two layers of gauze.

7. The method for preparing a friction-releasing aroma microcapsule as described in claim 6, characterized in that, The emulsifier is polyvinyl alcohol.

8. The method for preparing a friction-releasing aroma microcapsule as described in claim 6, characterized in that, The conditions for high-speed shearing were 7500 rpm for 15 min.

9. The method for preparing a friction-releasing aroma microcapsule as described in claim 6, characterized in that, The conditions for the heat preservation reaction are: temperature 50-80℃, reaction time 4-10 h.

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