Preparation method of paraffin microspheres

Abstract

The invention discloses a preparation method of paraffin microspheres, which comprises the following steps: uniformly mixing water, polyoxyethylene, absolute ethyl alcohol and paraffin according to a certain proportion, and heating until the paraffin is molten; the paraffin microspheres with different diameters are obtained through the technological methods of oscillation, cooling, unfreezing, washing, sieving and the like. The method is easy and convenient to operate, complex equipment is not needed, the needed raw materials are easy to obtain, and the production efficiency is high. Paraffin microspheres with different diameters can be obtained by adjusting the aperture of the screen, and different application requirements can be met. In addition, the whole process is low in energy consumption, the production cost is remarkably reduced, and a feasible solution is provided for industrial production of the paraffin microspheres.

Description

Technical Field

[0001] The invention relates to the technical field of new materials, and more specifically to a method for preparing paraffin microspheres. Background Art

[0002] With the development of advanced materials science and technology, microspheres, as an important micro-nano material, are widely used in drug delivery, catalysis, adsorption, sensors and new functional materials. Paraffin is a common low-density organic compound. Its stability, non-polarity and good biocompatibility make it an ideal material for preparing microspheres.

[0003] The preparation methods of paraffin microspheres mainly include aqueous emulsification, solvent evaporation and spray drying. The aqueous emulsification method is to dissolve paraffin in an organic solvent, then use a surfactant to form an emulsion in the aqueous phase, and finally remove the solvent by cooling or evaporation to obtain paraffin microspheres. This method has good controllability and adjustability, and can effectively achieve the regulation of the particle size, shape and distribution of microspheres. However, in the traditional preparation process of paraffin microspheres, it is usually necessary to add surfactants and emulsifiers to the solution, which not only increases the cost but also brings potential harm to paraffin in the biomedical field.

[0004] Although the current preparation technology has made certain progress, it still faces some challenges, such as the uniformity, load capacity and long-term stability of microspheres. Therefore, optimizing the preparation process of paraffin microspheres and avoiding the use of emulsifiers and dispersants are new directions for the preparation of paraffin microspheres. In order to better avoid the use of emulsifiers, many scholars have made many attempts. Xiao Zuoxu (preparing paraffin emulsions and paraffin microspheres with monodispersed P (DC-TMPTA) polymer microspheres as Pickering emulsion stabilizers) proposed a method in which solid particles can replace conventional emulsifiers. Although more regular paraffin microspheres can be obtained, crosslinkers and initiators are required to prepare solid particles during its preparation, and the process is relatively complicated. Chinese patent CN1051132020A uses PVA as a stabilizer and adopts a non-steering emulsification method to prepare a paraffin dispersion, and obtains paraffin microspheres with relatively uniform morphology. Summary of the invention

[0005] Based on this, in order to better avoid the use of emulsifiers and dispersants to prepare paraffin microspheres, the present invention uses polyethylene oxide as a stabilizer. Polyethylene oxide, as a water-soluble polymer, is often used to prepare biomedical materials and can improve the stability and suspension of microspheres. The addition of polyethylene oxide can change the density and viscosity of the solution. The lower density of paraffin causes floating in the polymer solution. In order to better solve this problem, the present invention adds anhydrous ethanol to reduce the density of the solution so that the paraffin is stably suspended. By mixing polyethylene oxide solution, anhydrous ethanol and paraffin together, a uniform dispersion system can be formed.

[0006] The technical solution of the present invention is as follows:

[0007] A method for preparing paraffin microspheres comprises: preparing a polyethylene oxide aqueous solution; uniformly mixing the polyethylene oxide aqueous solution and paraffin to obtain a solid-liquid mixture; subsequently adding anhydrous ethanol, and shaking the solid-liquid mixture in a high-temperature water bath to obtain an oil-water solution; and finally rapidly cooling the oil-water solution, thawing it naturally, and sieving it to obtain paraffin microspheres.

[0008] Furthermore, the preparation step specifically includes: accurately weighing polyethylene oxide according to a mass ratio of polyethylene oxide to water of 1 to 20:100, and adding an appropriate amount of purified water under stirring until a uniform polyethylene oxide aqueous solution is formed;

[0009] The paraffin wax and the polyethylene oxide aqueous solution are mixed in a mass ratio of 1 to 20:100, and stirred sufficiently to ensure that the paraffin wax is evenly dispersed in the polyethylene oxide aqueous solution to obtain a stable paraffin wax floating solution;

[0010] Gradually add 40% to 80% anhydrous ethanol to the paraffin floating solution, and continue stirring to mix to form a uniform paraffin suspension solution oil-water solution;

[0011] The oil-water solution is shaken in a water bath at 65 to 100° C. for 5 to 20 minutes to obtain a uniformly mixed oil-water solution; the oil-water solution is rapidly cooled in liquid nitrogen;

[0012] By melting naturally at room temperature, suspended paraffin microspheres can be obtained;

[0013] Pour the suspended paraffin microspheres into purified water, wash with purified water, let stand and take the upper floating matter;

[0014] Finally, the product is dried and sieved twice or more to obtain paraffin microspheres.

[0015] Furthermore, the molecular weight of the polyethylene oxide is 100000-1000000. The mass fraction of the polyethylene oxide is 5%-20%.

[0016] Furthermore, the amount of anhydrous ethanol added increases with the increase in the molecular weight and amount of polyethylene oxide added, and the specific mass fraction is 40% to 80%.

[0017] Furthermore, the cooling should be performed rapidly in liquid nitrogen or an ultra-low temperature refrigerator.

[0018] Furthermore, the natural melting requires that the frozen food be placed at room temperature to remain still and thaw.

[0019] Furthermore, the aperture of the sieve is in the range of 100 to 600 microns.

[0020] Furthermore, the sieving is performed by rinsing, and the rinsing process is performed by repeatedly rinsing and filtering with purified water at a water temperature of 0 to 37 degrees Celsius.

[0021] Furthermore, if the final application of paraffin wax is to utilize pore-forming materials in high-temperature calcined materials, no water washing process is required during the production process, and the high-temperature decomposition property of polyoxyethylene can be utilized to remove it without the need for a water washing step.

[0022] Technical effects and advantages of the present invention:

[0023] The present invention uses polyethylene oxide solution as a stabilizer to increase the viscosity of the solution, thereby providing a possibility for stable suspension of paraffin. At the same time, in order to better solve the problem that the density of polyethylene oxide and water is greater than that of paraffin, causing paraffin to float, the present invention uses anhydrous ethanol with a lower density and a lower price as a method for reducing the density of the solution. This method can significantly reduce the density of the solution, so that the paraffin can be stably suspended. By placing it in a water bath and heating and vibrating it, a suspended oil-water mixture can be obtained, and the mixture is quickly cooled to ensure the stable formation of paraffin microspheres. Finally, due to the addition of purified water, the paraffin microspheres are suspended, and paraffin microspheres with a diameter range of 10 to 700 microns can be obtained after rinsing, drying, and screening. The microspheres are relatively uniform and flat.

[0024] Compared with the prior art, no new emulsifier and dispersant are introduced to accelerate the emulsification or dispersion of paraffin when preparing paraffin microspheres. At the same time, the introduced polyethylene oxide has good biocompatibility, which provides a basis for the application of paraffin microspheres in the biomedical field.

[0025] Secondly, compared with the existing technology, the production process of paraffin microspheres has simple equipment, simple method, high production efficiency, safety and reliability, does not use more large machines, has low energy loss, and will not cause new pollution to the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the production and preparation flow chart of paraffin microspheres.

[0027] Figure 2 is a photograph of the paraffin suspension prepared in Example 1.

[0028] Figure 3 This is an optical microscope photograph of the paraffin wax prepared in Example 1.

[0029] Figure 4 This is an optical microscope photograph of the paraffin wax prepared in Example 1. DETAILED DESCRIPTION

[0030] The following will be combined with specific implementation methods and examples to specifically describe the embodiments of the present invention, and the advantages and various effects of the embodiments of the present invention will be more clearly presented. It should be understood by those skilled in the art that these specific implementation methods and examples are used to illustrate the embodiments of the present invention, rather than to limit the embodiments of the present invention.

[0031] Throughout the specification, unless otherwise specifically stated, the terms used herein should be understood as meanings commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which the embodiments of the present invention belong. In the event of a conflict, this specification takes precedence.

[0032] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the embodiments of the present invention can be purchased from the market or prepared by existing methods.

[0033] The technical solution provided by the embodiment of the present invention is to solve the above technical problems. The preliminary exploration solutions of the technical solution include:

[0034] 1. The present invention firstly mixes paraffin and water uniformly, heats and shakes them, and then rapidly cools them down. However, due to the different densities of paraffin and water, oil and water are separated, resulting in the formation of block paraffin.

[0035] 2. In order to better solve the problem of paraffin and water separation, the applicant introduced the addition of emulsifiers. However, due to the presence of emulsifiers, it is difficult for water to remove the emulsifiers. Common emulsifiers have certain potential toxicity, which will bring serious harm to the application of materials in biomedicine;

[0036] 3. In order to better suspend the paraffin, the applicant uses anhydrous ethanol as a solvent to reduce the density of the solution. The density of the solution can be configured to be the same as that of the paraffin, so that the paraffin is in a suspended state. However, the suspended paraffin is still unstable during the cooling process.

[0037] 4. Polyethylene oxide is a stabilizer that can increase the viscosity and density of the solution, and it is naturally non-toxic. Therefore, it is hoped that the stability of the suspension solution can be increased by introducing polyethylene oxide, but there are also problems such as the ratio of materials, oscillation time, and cooling method.

[0038] The technical solution provided by the embodiment of the present invention is to solve the above technical problems, and the overall idea is as follows:

[0039] During the research process, the applicant found that the best way to prepare paraffin microspheres is emulsion polymerization. Although simply crushing paraffin can obtain paraffin particles with smaller particle sizes, it will not form spherical paraffin with a relatively uniform shape.

[0040] The density of paraffin is between that of water and anhydrous ethanol. The paraffin can be suspended by adjusting the ratio of anhydrous ethanol to water. Suspended paraffin does not have better stability. Water-soluble and non-toxic polyethylene oxide can be introduced as a stabilizer.

[0041] The suspended paraffin particles are heated by shaking to prepare suspended droplets of paraffin microspheres.

[0042] In order to better generate paraffin microspheres from the paraffin in its suspended state, the solution can be quickly frozen and then thawed naturally. In the natural state, paraffin is solid, and its water and anhydrous ethanol are still liquid. Paraffin microspheres can be obtained by solid-liquid separation.

[0043] In some embodiments, the mass ratio of polyethylene oxide to water is 1-20:100.

[0044] In some embodiments, the mass ratio of paraffin wax to polyethylene oxide solution in the oil-water mixture is 1-20:100.

[0045] In some embodiments, the rapid cooling allows the solution to quickly drop below 0 degrees Celsius, and the solution can be quickly placed in liquid nitrogen for cooling.

[0046] In some embodiments, the natural thawing is to thaw naturally at room temperature of 20-35°C.

[0047] In some embodiments, the screening refers to a screening process using two or more sieves with apertures ranging from 10 to 700 microns.

[0048] The dermis layer, artificial skin and preparation method thereof of the present application will be described in detail below in combination with embodiments, control examples and experimental data.

[0049] Example 1

[0050] A method for preparing paraffin microspheres comprises:

[0051] Add 0.5g of polyethylene oxide to 50g of deionized water and stir until completely dissolved to obtain a uniform polyethylene oxide solution. Add 1g of solid paraffin particles to the solution, then slowly add 20g of anhydrous ethanol and ensure that it is fully dispersed. The mixed solution is then heated to 65°C and shaken for 30 minutes to promote interaction. The oil-water mixed solution is then quickly placed in liquid nitrogen to cool until freezing is visible, and maintained in this state for 5 minutes. The frozen oil-water solution is naturally thawed at room temperature, washed with deionized water 2-3 times, and the upper floating matter is collected. The washed solid is placed in a spin dryer and then sieved through 100 micron and 500 micron sieves in turn to obtain paraffin microspheres with a diameter in the range of 100-500 microns.

[0052] Example 2

[0053] A method for preparing paraffin microspheres comprises:

[0054] Add 10g of polyethylene oxide to 100g of deionized water and stir until completely dissolved to obtain a uniform polyethylene oxide solution. Add 5g of solid paraffin particles to the solution, then slowly add 60g of anhydrous ethanol and ensure that it is fully dispersed. Then heat the mixed solution to 75°C and shake for 30 minutes to promote interaction. Then quickly put the oil-water mixed solution into liquid nitrogen to cool it down until freezing is visible, and keep this state for 5 minutes. The frozen oil-water solution is thawed naturally at room temperature, washed with deionized water 2-3 times, and the upper floating matter is collected. The washed solid is placed in a spin dryer and then sieved through 100 micron and 500 micron sieves in turn to obtain paraffin microspheres with a diameter in the range of 100-500 microns.

[0055] Example 3

[0056] A method for preparing paraffin microspheres comprises:

[0057] 15g of polyethylene oxide (PEO) was added to 100g of deionized water and stirred until completely dissolved to obtain a uniform polyethylene oxide solution. 5g of solid paraffin particles were added to the solution, followed by slow addition of 80g of anhydrous ethanol to ensure that it was fully dispersed. The mixed solution was then heated to 75°C and shaken for 30 minutes to promote interaction. The oil-water mixed solution was then quickly placed in liquid nitrogen to cool until ice formation was visible, and maintained in this state for 5 minutes. The frozen oil-water solution was thawed naturally at room temperature, washed 2-3 times with deionized water, and the upper floating matter was collected. The cleaned solid was placed in a spin dryer and then sieved through 100 micron and 500 micron sieves in turn to obtain paraffin microspheres with a diameter in the range of 100-500 microns.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing paraffin microspheres, characterized in that: include: preparing a polyethylene oxide aqueous solution; uniformly mixing the polyethylene oxide aqueous solution and paraffin to obtain a solid-liquid mixture; Then, anhydrous ethanol is added, and the solid-liquid mixture is placed in a high-temperature water bath and shaken to obtain an oil-water solution; finally, the oil-water solution is rapidly cooled, thawed naturally, and sieved to obtain paraffin microspheres.

2. The method for preparing paraffin microspheres according to claim 1, characterized in that: The preparation steps specifically include: accurately weighing polyethylene oxide according to a mass ratio of polyethylene oxide to water of 1 to 20:100, and adding an appropriate amount of purified water under stirring until a uniform polyethylene oxide aqueous solution is formed; The paraffin wax and the polyethylene oxide aqueous solution are mixed in a mass ratio of 1 to 20:100, and stirred sufficiently to ensure that the paraffin wax is evenly dispersed in the polyethylene oxide aqueous solution to obtain a stable paraffin wax floating solution; Gradually add 40% to 80% anhydrous ethanol to the paraffin floating solution, and continue stirring to mix to form a uniform paraffin suspension solution oil-water solution; The oil-water solution is shaken in a water bath at 65 to 100° C. for 5 to 20 minutes to obtain a uniformly mixed oil-water solution; the oil-water solution is rapidly cooled in liquid nitrogen; By melting naturally at room temperature, suspended paraffin microspheres can be obtained; Pour the suspended paraffin microspheres into purified water, wash with purified water, let stand and take the upper floating matter; Finally, the product is dried and sieved twice or more to obtain paraffin microspheres.

3. The method for preparing paraffin microspheres according to claim 1, characterized in that: The molecular weight of the polyethylene oxide is 100,000-1,000,000.

4. The method for preparing paraffin microspheres according to claim 1, characterized in that: The mass fraction of the polyethylene oxide is 5% to 20%.

5. The method for preparing paraffin microspheres according to claim 1, characterized in that: The amount of anhydrous ethanol added increases with the increase of the molecular weight and amount of polyethylene oxide, and the specific mass fraction is 40% to 80%.

6. The method for preparing paraffin microspheres according to claim 1, characterized in that: The cooling should be rapid cooling in liquid nitrogen or an ultra-low temperature refrigerator.

7. The method for preparing paraffin microspheres according to claim 1, characterized in that: The natural melting requires that the food be placed at room temperature to remain still and thaw.

8. The method for preparing paraffin microspheres according to claim 1, characterized in that: The aperture of the screen mesh ranges from 100 to 600 microns.

9. The method for preparing paraffin microspheres according to claim 1, characterized in that: Rinse during sieving. The rinsing process is to repeatedly rinse and filter with purified water at a water temperature of 0 to 37 degrees Celsius.

10. The method for preparing paraffin microspheres according to claim 1, characterized in that: If the final application of paraffin wax is to utilize the pore-forming material in the high-temperature calcined material, no water washing process is required in the production process. The high-temperature decomposition property of polyoxyethylene can be utilized to remove it without the water washing step.

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