Polyurea microcapsule with rough surface and preparation method thereof

Abstract

The invention discloses a polyurea microcapsule with a rough surface and a preparation method thereof, and the polyurea microcapsule with the rough surface comprises the following components: a polyurea wall material, essence, hydrophobic silicon dioxide and an emulsifier, wherein the polyurea wall material is an elastomer substance generated by reaction of isophorone diisocyanate and tetramethylethylenediamine; the proportions of the isophorone diisocyanate and the tetramethylethylenediamine in the system are respectively 5 to 50 weight percent and 1 to 10 weight percent. The polyurea microcapsule with the rough surface can slowly release essence and still has a continuous fragrance retaining effect under a high-temperature condition, and meanwhile, the surface of the microcapsule has high roughness, so that the contact area of the microcapsule on a fabric is increased, the loss of the microcapsule in the use process of the fabric is reduced, and the service life of the fabric is prolonged. The development of the perfumed functional textile is further promoted, and the application prospect is good.

Description

Technical Field

[0001] The invention relates to the technical field of natural high molecular polymers, and relates to a polyurea microcapsule with a rough surface and a preparation method thereof. Background Art

[0002] Fragrances are easily affected by the external environment such as oxygen, light, and temperature, and are prone to oxidation and volatilization during use and storage. Microencapsulation technology can maintain the original characteristics and stability of flavors.

[0003] Polyurea system refers to an elastomeric polymer produced by the reaction of isocyanate and amino compounds. It has the characteristics of high strength, high wear resistance and chemical corrosion resistance. Polyurea microcapsules are safe and green during production and application, and meet environmental protection requirements. Microcapsules formed by polyurea as wall material can effectively wrap various core materials (such as flavors, drugs, active ingredients, etc.), improve the encapsulation rate, and give the core material good physical and chemical stability, protecting the core material from the influence of the external environment such as oxygen, moisture, light, heat, etc.

[0004] With the improvement of living standards, consumers' demand for textiles is no longer limited to basic warmth and body covering functions, but more pursuit of personalization, comfort and emotional experience. Fragrance textiles just meet this psychological demand and can provide pleasant olfactory enjoyment. With the enhancement of environmental awareness, fragrance textiles made of natural, degradable materials and environmentally friendly production processes will become more popular. The research and development of harmless and biodegradable fragrance microcapsules will be the key direction for the development of the industry. The development of microcapsule embedding technology makes the embedding of fragrance ingredients more efficient, durable and controllable, while maintaining the original texture and durability of textiles. Technological progress will further promote the quality improvement and cost reduction of fragrance textiles. Microcapsules with rough surfaces increase the contact area between microcapsules and fabrics, which helps to improve the bonding strength between the two. At the same time, it can reduce the loss of microcapsules during the use of fabrics and increase the service life of fragrance textiles.

[0005] Therefore, it is of great practical significance to develop a polyurea microcapsule with rough surface. Summary of the invention

[0006] Due to the above-mentioned defects in the prior art, the present invention provides a rough-surfaced polyurea microcapsule and a preparation method thereof, which has high strength, good wear resistance, good chemical corrosion resistance and long service life, and combines the advantages of a polyurea system and a rough surface.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A polyurea microcapsule with a rough surface comprises the following components: a polyurea wall material, an essence, hydrophobic silica and an emulsifier;

[0009] The polyurea wall material is an elastomeric substance generated by the reaction of isophorone diisocyanate and tetramethylethylenediamine, and the proportions of isophorone diisocyanate and tetramethylethylenediamine in the system are 5-50 wt% and 1-10 wt%, respectively.

[0010] The polyurea microcapsules with a rough surface of the present invention use interfacial polymerization technology to form polyurea wall materials through polymerization reaction of isocyanate monomers and amine monomers at the oil-water interface, thereby completing the embedding of flavors, and at the same time stabilizing hydrophobic silica on the wall materials, which can increase the surface roughness of the microcapsules, so that the polyurea microcapsules with a rough surface have the characteristics of high roughness, long-lasting fragrance, high temperature resistance and the like.

[0011] As the preferred technical solution:

[0012] In the polyurea microcapsule with a rough surface as described above, the fragrance accounts for 10-30wt% in the system. The fragrance includes but is not limited to one or more of rose fragrance, daylily fragrance, jasmine fragrance or other fragrances, essential oils, fragrances and other combinations containing volatile aroma substances.

[0013] In the polyurea microcapsule with a rough surface as described above, the hydrophobic silica accounts for 1 to 6 wt % of the system and has a particle size of 50 nm.

[0014] In the polyurea microcapsule with a rough surface as described above, the emulsifier is a polyvinyl alcohol solution.

[0015] The polyurea microcapsule with a rough surface as described above, wherein the concentration of the polyvinyl alcohol solution is 8-12wt%, and the alcoholysis degree is 87-89%;

[0016] The polyvinyl alcohol solution accounts for 8-12 wt % in the system.

[0017] The polyurea microcapsule having a rough surface as described above further comprises a balance of water.

[0018] In addition, the present invention also provides a method for preparing the polyurea microcapsule having a rough surface as described above, comprising the following steps:

[0019] S1, dissolving the emulsifier in deionized water to obtain aqueous phase A;

[0020] S2, mixing isophorone diisocyanate, essence and hydrophobic silica in proportion to obtain an oil phase B;

[0021] S3, slowly adding the oil phase B into the water phase A, and forming a uniform oil-in-water emulsion by high-speed shearing;

[0022] S4, adding tetramethylethylenediamine to the oil-in-water emulsion obtained in S3, mixing evenly, and then transferring the mixture to a water bath in a sealed state, stirring at a uniform speed and reacting in a water bath at a constant temperature;

[0023] S5, performing heat preservation reaction to obtain a microcapsule suspension;

[0024] S6. Perform post-processing.

[0025] In step S4 of the present invention, the transfer rate of the amine monomer to the organic phase is promoted through the interfacial polymerization reaction, so that the reaction monomers are fully mixed, thereby promoting the full progress of the interfacial polymerization reaction to form a highly cross-linked microcapsule wall material. Stirring is performed while the microcapsule wall material is solidified. As the stirring proceeds, the molecules in the medium continue to move, which is conducive to the stabilization of the hydrophobic silica on the wall material, thereby achieving the effect of increasing the surface roughness of the microcapsule.

[0026] The preparation method is efficient, simple in process, suitable for large-scale production and has good application prospects.

[0027] As the preferred technical solution:

[0028] In the method as described above, the shear rate of the high-speed shearing is 1000-20000 rpm, and the shearing time is 1-15 min.

[0029] In the method as described above, the conditions for the heat preservation reaction are: temperature 50-80°C, and reaction time 3-15 h.

[0030] In the method as described above, the post-treatment refers to filtering the microcapsule suspension using multiple layers of gauze.

[0031] In the present invention, the present invention proves through experiments that the diameter of the rough-surfaced microcapsules of the present invention can be controlled by the emulsification shear rate, the surface roughness of the microcapsules can be controlled by the amount of hydrophobic silica, and the amount of silica has a significant effect on the surface roughness of the microcapsules.

[0032] Preferably, the method for preparing polyurea microcapsules having a rough surface comprises the following steps:

[0033] Step 1: Preparation of aqueous phase: Weigh a certain mass of polyvinyl alcohol and add it to water. Use a high-pressure homogenizer to shear at 3000 rpm for 10 s to fully dissolve it.

[0034] Step 2, preparation of oil phase: Weigh a certain mass of hydrophobic silica and dissolve it in the essence in proportion, and mix it with a certain mass of isophorone diisocyanate, and use a magnetic stirrer to fully stir and dissolve, the stirring speed is 500 rpm, and the stirring time is 10 min.

[0035] Step 3: slowly add the oil phase obtained in step 2 to the water phase obtained in step 1, and then shear the mixture at 12000 rpm for 6 min to obtain an oil-in-water emulsion.

[0036] Step 4: Keep the oil-in-water emulsion at 65° C. and 300 rpm for 5 min.

[0037] Step 5: Increase the rotation speed to 500 rpm and add tetramethylethylenediamine into the system to initiate the reaction.

[0038] Step 6: After mixing evenly, seal and transfer to a water bath, control the temperature of the water bath at 65°C, and react for 30 minutes to fully polymerize isophorone diisocyanate and tetramethylethylenediamine.

[0039] Step 7: Maintain the system temperature at 65°C and react for 5.5 hours to solidify the microcapsule wall material.

[0040] Step 8: Filter with two layers of gauze to obtain a suspension of fragrance microcapsules with polyurea as the wall material.

[0041] Furthermore, the present invention also provides an application of the polyurea microcapsule with a rough surface in the textile field, and the application method is as follows: the prepared polyurea microcapsule suspension with a rough surface is used as a soaking solvent for textile fabrics, and after soaking for 1 hour, it is placed in a 60°C oven for drying.

[0042] The above technical solution is only a feasible technical solution of the present invention, and the protection scope of the present invention is not limited thereto. Those skilled in the art can reasonably adjust the specific design according to actual needs.

[0043] The above invention has the following advantages or beneficial effects:

[0044] (1) The polyurea microcapsules with a rough surface of the present invention are prepared by using hydrophobic silica and isophorone diisocyanate as composite wall materials. The addition of hydrophobic silica allows the silica to be embedded in the surface of the polyurea wall material, so that the microcapsules have a rougher shell, and thus the microcapsules have a higher adhesion effect when used on textiles;

[0045] (2) The method for preparing the polyurea microcapsules with rough surfaces of the present invention has a simple preparation process, does not require complicated instruments and equipment, is green and pollution-free, has high production efficiency, and can meet the needs of large-scale industrial production;

[0046] (3) The method for preparing polyurea microcapsules with rough surfaces of the present invention can change the surface roughness of the polyurea microcapsules by adjusting the amount of hydrophobic silica, so that the roughness of the microcapsules is controllable;

[0047] (4) In the method for preparing polyurea microcapsules with rough surfaces of the present invention, the added hydrophobic silica can be changed to other additives according to the specific needs during use. Different additives can not only improve the surface roughness of the microcapsules but also make the microcapsules have different functions, and the application prospects are good. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The present invention and its features, appearance and advantages will become more apparent by reading the detailed description of non-limiting embodiments with reference to the following drawings. The same reference numerals indicate the same parts in all the drawings. The drawings are not drawn to scale, and emphasis is placed on illustrating the subject matter of the present invention.

[0049] Figure 1 The scanning electron microscope images of the polyurea microcapsules with rough surfaces prepared in Example 1, wherein Figure A is a scanning electron microscope image of the prepared microcapsules; Figure B is a scanning electron microscope image of the prepared microcapsules deposited on a fabric;

[0050] Figure 2 is a scanning electron microscope image of the polyurea microcapsules with rough surfaces prepared in Example 2;

[0051] Figure 3 This is a scanning electron microscope image of the polyurea microcapsules with a rough surface prepared in Example 3;

[0052] Figure 4 This is a scanning electron microscope image of the polyurea microcapsules prepared in the comparative example. DETAILED DESCRIPTION

[0053] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0054] Example 1

[0055] A method for preparing polyurea microcapsules with a rough surface comprises the following steps:

[0056] Step 1: Preparation of aqueous phase: Add a polyvinyl alcohol solution (12 wt %) with a mass concentration of 10 wt % and a degree of alcoholysis of 87-89% to deionized water, and use a high-pressure homogenizer to shear at 3000 rpm for 10 s to fully dissolve it.

[0057] Step 2, preparation of oil phase: flavor (system proportion of 12wt%) and hydrophobic silica (system proportion of 3wt%, its particle size of 50nm) are mixed, and mixed with isophorone diisocyanate (system proportion of 12wt%), and stirred and dissolved with a magnetic stirrer at a speed of 500 rpm and a stirring time of 10 min.

[0058] Step 3: slowly add the oil phase obtained in step 2 to the water phase obtained in step 1, and then shear the mixture at 12000 rpm for 6 min to obtain an oil-in-water emulsion.

[0059] Step 4: Keep the oil-in-water emulsion at 65° C. and 300 rpm for 5 min.

[0060] Step 5: Increase the rotation speed to 500 rpm and add tetramethylethylenediamine (1 wt% of the system) into the system to initiate the reaction.

[0061] Step 6: After mixing evenly, seal and transfer to a water bath, control the temperature of the water bath at 65°C, and react for 30 minutes to fully polymerize isophorone diisocyanate and tetramethylethylenediamine.

[0062] Step 7: Maintain the system temperature at 65°C and react for 5.5 hours to solidify the microcapsule wall material.

[0063] Step 8: Filter with two layers of gauze to obtain a suspension of fragrance microcapsules with polyurea as the wall material.

[0064] Example 2

[0065] A method for preparing polyurea microcapsules with a rough surface is basically the same as Example 1, except that the amount of hydrophobic silica added in step 2 is adjusted to 1 wt %.

[0066] Example 3

[0067] A method for preparing polyurea microcapsules with a rough surface is basically the same as Example 1, except that the amount of hydrophobic silica added in step 2 is adjusted to 5 wt %.

[0068] Comparative Example

[0069] A method for preparing polyurea microcapsules is basically the same as that of Example 1, except that hydrophobic silica is not added in step 2.

[0070] The surface roughness of the polyurea microcapsules with rough surfaces prepared in Examples 1 to 3 and the polyurea microcapsules prepared in the comparative example was measured using a scanning electron microscope. The scanning electron microscope images of Examples 1 to 3 and the comparative example are shown in FIG. Figure 1 A. Figure 2 , Figure 3 and Figure 4As shown in the figure, it can be seen that the surface of the polyurea microcapsule with a rough surface prepared by the present invention has a large amount of hydrophobic silica on the surface and the surface roughness of the microcapsule decreases with the decrease of the amount of hydrophobic silica used and increases with the increase of the amount used. The surface of the polyurea microcapsule prepared in the comparative example without adding hydrophobic silica is smooth and has low roughness;

[0071] At the same time, the obtained polyurea microcapsules with rough surfaces were tested for thermal stability and friction fragrance release performance. The specific test method is as follows: the fragrance microcapsule suspension with polyurea as the wall material obtained in Example 1 was used as the soaking solvent for textile fabrics. After soaking for 1 hour, it was placed in a 60°C oven for drying. After friction, the fragrance was evaluated by smelling, and the surface of the fabric was observed by scanning electron microscopy. Figure 1 As shown in B, it can be seen from the figure that a large number of polyurea microcapsules with rough surfaces are deposited on the surface of the fabric. It can be seen that the polyurea microcapsules with rough surfaces have good thermal stability and good friction fragrance release performance.

[0072] Those skilled in the art should understand that those skilled in the art can implement variations by combining the prior art and the above embodiments, which will not be described in detail here. Such variations do not affect the essential content of the present invention, and will not be described in detail here.

[0073] The above describes the preferred embodiments of the present invention. It should be understood that the present invention is not limited to the above-mentioned specific embodiments, and the devices and structures that are not described in detail should be understood to be implemented in a common manner in the art; any technician familiar with the art can use the above-disclosed methods and technical contents to make many possible changes and modifications to the technical solutions of the present invention without departing from the scope of the technical solutions of the present invention, or modify them into equivalent embodiments of equivalent changes, which does not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention are still within the scope of protection of the technical solutions of the present invention.

Claims

1. A polyurea microcapsule having a rough surface, characterized in that: It includes the following components: polyurea wall material, fragrance, hydrophobic silica and emulsifier; The polyurea wall material is an elastomeric substance generated by the reaction of isophorone diisocyanate and tetramethylethylenediamine, and the proportions of isophorone diisocyanate and tetramethylethylenediamine in the system are 5-50 wt% and 1-10 wt%, respectively.

2. The polyurea microcapsule having a rough surface according to claim 1, characterized in that: The fragrance accounts for 10-30 wt % in the system.

3. The polyurea microcapsule with a rough surface according to claim 1, characterized in that: The hydrophobic silica accounts for 1-6 wt % in the system, and the particle size of the hydrophobic silica is 50 nm.

4. The polyurea microcapsule with a rough surface according to claim 1, characterized in that: The emulsifier is polyvinyl alcohol solution.

5. The polyurea microcapsule with a rough surface according to claim 4, characterized in that: The concentration of the polyvinyl alcohol solution is 8-12 wt %, and the alcoholysis degree is 87-89%; The polyvinyl alcohol solution accounts for 8-12 wt % in the system.

6. The polyurea microcapsule with a rough surface according to claim 5, characterized in that: The polyurea microcapsules having a rough surface further include a balance of water.

7. A method for preparing a polyurea microcapsule having a rough surface as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: S1, dissolving the emulsifier in deionized water to obtain aqueous phase A; S2, mixing isophorone diisocyanate, essence and hydrophobic silica in proportion to obtain an oil phase B; S3, slowly adding the oil phase B into the water phase A, and forming a uniform oil-in-water emulsion by high-speed shearing; S4, adding tetramethylethylenediamine to the oil-in-water emulsion obtained in S3, mixing evenly, and then transferring the mixture to a water bath in a sealed state, stirring at a uniform speed and reacting in a water bath at a constant temperature; S5, performing heat preservation reaction to obtain a microcapsule suspension; S6. Perform post-processing.

8. The method according to claim 7, characterized in that The shear rate of the high-speed shearing is 1000-20000 rpm, and the shearing time is 1-15 min.

9. The method according to claim 7, characterized in that: The conditions for the heat preservation reaction are: temperature 50-80°C, and reaction time 3-15 h.

10. The method according to claim 7, characterized in that The post-treatment refers to filtering the microcapsule suspension with multiple layers of gauze.

Images