Hydrophilic elastic micron-sized monodisperse organic silicon microsphere and preparation method thereof

Abstract

The invention relates to the technical field of organic silicon microspheres, in particular to hydrophilic elastic micron-sized monodisperse organic silicon microspheres and a preparation method thereof, and the preparation method specifically comprises the following steps: adding an organic solvent and an acidic catalyst into a reaction kettle 1 filled with deionized water, then adding a monomer containing carbon double bonds, and carrying out hydrolysis reaction under an acidic condition. The method comprises the following steps: adding an acidic catalyst into a reaction kettle 2 filled with deionized water, and then adding a trialkoxysilane monomer to carry out hydrolysis reaction under an acidic condition; the method comprises the following steps: adding a dialkoxy silane monomer into a reaction kettle 3 filled with deionized water, and carrying out hydrolysis reaction under a neutral condition; basic catalysts are respectively added into the reaction kettle 2 and the reaction kettle 3, so that the reaction kettle 2 and the reaction kettle 3 are respectively subjected to condensation reaction; mixing reactants in the reaction kettle 2 and the reaction kettle 3, enabling the organic silicon microspheres formed in the reaction kettle 2 to react with the organic silicon chain polymer formed in the reaction kettle 3, and finally adding the hydrolyzed silanol containing the carbon-carbon double bond in the reaction kettle 1 into the system for blocking.

Description

Technical Field

[0001] The present invention relates to the technical field of organosilicon microspheres, in particular to hydrophilic elastic micron-sized monodisperse organosilicon microspheres and a preparation method thereof. Background Art

[0002] Silicone microspheres are fine, spherical powders with a regular appearance. Their molecular structure is a three-dimensional cross-linked network, a unique structure that imparts excellent heat resistance, dispersibility, and stability. They possess exceptional optical properties, excellent heat resistance and stability, and good lubricity and feel. They are widely used in light diffusion materials, plastics and rubber, coatings and inks, cosmetics, medical treatments, electronics, and other fields.

[0003] In terms of preparing micron-sized organosilicon microspheres, there are relatively mature preparation schemes in China. In a Chinese patent (CN105949464B), by preparing a seed solution and further performing hydrolysis and condensation, micron-sized monodisperse polysiloxane microspheres with controllable particle size and easy mass production can be obtained, which can be applied to the field of light diffusion. In a Chinese patent (CN115636937B), by mixing and hydrolyzing dialkoxysilane and trialkoxysilane, hydrophobic, particle-size-controlled organosilicon resin microspheres can be prepared. Due to their hydrophobic properties, their application in water-based cosmetics, coatings, etc. is limited. In a Chinese patent (CN109369861B), by mixing and hydrolyzing methylsilane and vinylsilane, hydrophilic organosilicon microspheres can be prepared. Since their vinyl groups are located on the main body of the organosilicon microspheres, their heat resistance is relatively weak, and they are rigid microspheres, which have limited application in the field of cosmetics. In the Chinese patent (CN111500067B), elastic silicone microspheres are prepared using a hydrosilylation emulsion method. After the reaction is completed, the emulsifier and platinum catalyst need to be recovered. The synthesis cost is high and is not conducive to large-scale industrial production. Summary of the Invention

[0004] In order to solve the above technical problems existing in the prior art, the present invention provides a hydrophilic elastic micron-sized monodisperse organosilicon microsphere and a preparation method thereof, as follows:

[0005] A method for preparing hydrophilic elastic micron-sized monodisperse organosilicon microspheres comprises the following steps:

[0006] (1) Adding an organic solvent and an acidic catalyst to a reactor 1 filled with deionized water to prepare a solvent catalyst solution at a temperature of 25 to 50° C., a stirring speed of 100 to 500 rpm, a time of 5 to 30 minutes, and a pH value of 2 to 5; after stirring evenly, adding a monomer containing a carbon double bond and performing a hydrolysis reaction under acidic conditions at a temperature of 25 to 50° C., a stirring speed of 300 to 500 rpm, and a time of 2 to 8 hours;

[0007] (2) adding an acidic catalyst to a reactor 2 filled with deionized water to prepare an acidic catalyst solution, wherein the catalyst solution is prepared at a temperature of 25 to 50° C., a stirring speed of 100 to 500 rpm, a time of 5 to 10 minutes, and a pH value of 2 to 5; after stirring evenly, adding a trialkoxysilane monomer to carry out a hydrolysis reaction under acidic conditions at a temperature of 25 to 50° C., a stirring speed of 100 to 500 rpm, and a time of 45 to 60 minutes;

[0008] (3) While carrying out step (1), add dialkoxysilane monomer to the reaction kettle 3 filled with deionized water, and carry out hydrolysis reaction under neutral conditions at a temperature of 25 to 50° C., a stirring speed of 100 to 500 rpm, and a time of 30 to 60 min;

[0009] (4) adding a basic catalyst to reactor 2 and reactor 3 respectively to cause a condensation reaction at a temperature of 25 to 50° C., a stirring speed of 100 to 300 rpm, and a time of 5 to 45 min;

[0010] (5) mixing the reactants in reactor 2 and reactor 3 to allow the organosilicon microspheres formed in reactor 2 to react with the organosilicon chain polymer formed in reactor 3;

[0011] (6) Finally, the silanol containing carbon-carbon double bonds that has been hydrolyzed in reactor 1 is added to the system for end-capping.

[0012] Furthermore, the organic solvent in step (1) is methanol, ethanol, tetrahydrofuran, acetone, etc., and the ratio of the organic solvent to deionized water is (5-30):100; the acidic catalyst is any one or more of acetic acid, citric acid, oxalic acid, dilute sulfuric acid, and hydrochloric acid mixed in any proportion, and the ratio of the organic solvent to deionized water is (0.01-5):100; the carbon double bond-containing monomer is any one or more of dimethylvinylmethoxysilane, dimethylvinylethoxysilane, and tetramethyldivinyldisiloxane mixed in any proportion, and the ratio of the organic solvent to deionized water is (0.01-1):100.

[0013] Furthermore, the acidic catalyst in step (2) is any one or more of acetic acid, citric acid, oxalic acid, dilute sulfuric acid, and hydrochloric acid mixed in any proportion, and the ratio of the acidic catalyst to deionized water is (0.01-5):100; the trialkoxysilane monomer is any one or more of methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, and ethyltriethoxysilane mixed in any proportion, and the ratio of the acidic catalyst to deionized water is (5-20):100;

[0014] Furthermore, the dialkoxysilane monomer in step (3) is any one or more of dimethyldimethoxysilane and dimethyldiethoxysilane mixed in any proportion, and the ratio of the dialkoxysilane monomer to deionized water is (1-10):100.

[0015] Furthermore, the alkaline catalyst in step (4) is any one or more of ammonia water, sodium hydroxide aqueous solution, ethanolamine aqueous solution, and triethanolamine aqueous solution mixed in any proportion, and the ratio of the alkaline catalyst to deionized water is (0.01-2):100.

[0016] Furthermore, in step (4), an alkaline catalyst is added to the reactor 2 to carry out the reaction.

[0017] Furthermore, the alkaline catalyst is 1% sodium hydroxide aqueous solution or ammonia water, the reaction temperature is 25 to 35 minutes, the stirring speed is 100 to 200 rpm, and the time is 5 to 15 minutes.

[0018] Furthermore, the alkaline catalyst is a 1% ethanolamine aqueous solution or a 1% triethanolamine aqueous solution, the reaction temperature is 25-40° C., the stirring speed is 100-200 rpm, and the reaction time is 15-30 min.

[0019] A hydrophilic elastic micron-sized monodisperse organosilicon microsphere is prepared by the above method.

[0020] Compared with the prior art, the technical effects created by the present invention are embodied in:

[0021] (1) The present invention adopts the hydrolysis-condensation method for production, thus avoiding the cost increase caused by the use of a large amount of emulsifiers and platinum catalysts in other elastic microsphere hydrosilylation emulsion production processes, and the subsequent complicated process of recycling and treating the emulsifiers and catalysts.

[0022] (2) The vinyl group in this product is located at the end of the elastic chain. Unlike other processes that condense the vinyl group with the microsphere body, it has less impact on the heat resistance of the product and has both elastic groups and hydrophilic groups. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a scanning electron microscope image of the product of Example 1 of the present invention;

[0024] Figure 2 This is a particle size analysis diagram of the product of Example 1 of the present invention;

[0025] Figure 3 This is a scanning electron microscope image of the product of Example 2 of the present invention;

[0026] Figure 4 This is a particle size analysis diagram of the product of Example 2 of the present invention;

[0027] Figure 5 This is an electron microscope image of the product of Example 3 of the present invention;

[0028] Figure 6 This is a particle size analysis diagram of the product of Example 3 of the present invention. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is further defined below in conjunction with specific implementation methods, but the scope of protection required is not limited to the description.

[0030] Example 1

[0031] (1) 300 g of deionized water, 100 g of ethanol, and 5 g of acetic acid were added to reactor 1, respectively, at a temperature of 50°C, a stirring speed of 450 rpm, a time of 15 min, and a pH value of 2.72; 1 g of dimethylvinylmethoxysilane was then added, and a hydrolysis reaction was carried out under acidic conditions at a temperature of 50°C, a stirring speed of 500 rpm, and a time of 6 h;

[0032] (2) Add 0.2 g of acetic acid to reactor 2 containing 300 g of deionized water at 25° C., stirring at 300 rpm for 5 min, and pH 3.41; after stirring evenly, add 50 g of methyltrimethoxysilane monomer and allow it to hydrolyze under acidic conditions at 25° C., stirring at 300 rpm for 60 min;

[0033] (3) While carrying out step (1), 5 g of dimethyldimethoxysilane monomer was added to the reaction kettle 3 containing 300 g of deionized water, and the mixture was hydrolyzed under neutral conditions at a temperature of 25° C., a stirring speed of 300 rpm, and a time of 50 min;

[0034] (4) Add 3.5 g of sodium hydroxide to each of the reactors 2 and 3, respectively, and allow them to undergo condensation reaction at 35°C, stirring at 200 rpm, and for 15 min;

[0035] (5) The reactants in reactors 2 and 3 are mixed to allow the organic silicon microspheres formed in reactor 2 to react with the organic silicon chain polymer formed in reactor 3. Finally, the dimethyl vinyl silanol hydrolyzed in reactor 1 is added to the system for end-capping to obtain a vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane cross-linked polymer.

[0036] Example 2

[0037] (1) 300 g of deionized water, 80 g of methanol, and 8 g of citric acid were added to the reactor 1, respectively, at a temperature of 50°C, a stirring speed of 450 rpm, a time of 15 min, and a pH value of 2.01; 1.3 g of dimethylvinylethoxysilane was then added, and a hydrolysis reaction was carried out under acidic conditions at a temperature of 50°C, a stirring speed of 500 rpm, and a time of 5 h;

[0038] (2) Add 0.2 g of citric acid to reactor 2 containing 300 g of deionized water at 25° C., stirring at 300 rpm for 5 min, and pH 2.8; after stirring evenly, add 65 g of methyltriethoxysilane monomer and allow it to hydrolyze under acidic conditions at 25° C., stirring at 300 rpm for 50 min;

[0039] (3) While carrying out step (1), 5 g of dimethyldiethoxysilane monomer was added to the reactor 3 containing 300 g of deionized water, and the mixture was hydrolyzed under neutral conditions at a temperature of 25° C., a stirring speed of 300 rpm, and a time of 45 min;

[0040] (4) Add 9.1 g of 25% aqueous ammonia to each of Reactor 2 and Reactor 3 to allow condensation reaction to occur at 40°C, stirring at 200 rpm, and for 12 min.

[0041] (5) The reactants in reactors 2 and 3 are mixed to allow the organic silicon microspheres formed in reactor 2 to react with the organic silicon chain polymer formed in reactor 3. Finally, the dimethyl vinyl silanol hydrolyzed in reactor 1 is added to the system for end-capping to obtain a vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane cross-linked polymer.

[0042] Example 3

[0043] (1) 300 g of deionized water, 125 g of acetone, and 2 g of 30% dilute sulfuric acid were added to reactor 1, respectively, at a temperature of 50° C., a stirring speed of 450 rpm, a reaction time of 15 min, and a pH value of 1.63; 0.7 g of tetramethyldivinyldisiloxane was then added, and a hydrolysis reaction was carried out under acidic conditions at a temperature of 50° C., a stirring speed of 500 rpm, and a reaction time of 5 h;

[0044] (2) Add 0.2 g of oxalic acid to reactor 2 containing 300 g of deionized water at 25°C, stirring at 300 rpm for 5 min, and pH 2.16; after stirring evenly, add 55 g of methyltrimethoxysilane monomer and allow it to hydrolyze under acidic conditions at 25°C, stirring at 300 rpm for 60 min;

[0045] (3) While carrying out step (1), 7 g of dimethyldiethoxysilane monomer was added to the reactor 3 containing 300 g of deionized water, and the mixture was hydrolyzed under neutral conditions at a temperature of 25° C., a stirring speed of 300 rpm, and a time of 55 min;

[0046] (4) Add 3.49 g of triethanolamine to each of Reactor 2 and Reactor 3, respectively, and allow them to undergo condensation reaction at 35°C, stirring at 200 rpm, and for 15 min;

[0047] (5) The reactants in reactors 2 and 3 are mixed to allow the organic silicon microspheres formed in reactor 2 to react with the organic silicon chain polymer formed in reactor 3. Finally, the dimethyl vinyl silanol hydrolyzed in reactor 1 is added to the system for end-capping to obtain a vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane cross-linked polymer.

[0048] Finally, it should be noted that the above embodiments are merely representative examples of the present invention. Obviously, the technical solutions of the present invention are not limited to the above embodiments and are subject to numerous variations. All variations that can be directly derived or conceived by a person of ordinary skill in the art from the disclosure of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A method for preparing hydrophilic elastic micron-sized monodisperse organosilicon microspheres, characterized in that: The steps include: (1) Adding an organic solvent and an acidic catalyst to a reactor 1 filled with deionized water to prepare a solvent catalyst solution at a temperature of 25 to 50° C., a stirring speed of 100 to 500 rpm, a time of 5 to 30 minutes, and a pH value of 2 to 5; after stirring evenly, adding a monomer containing a carbon double bond and performing a hydrolysis reaction under acidic conditions at a temperature of 25 to 50° C., a stirring speed of 300 to 500 rpm, and a time of 2 to 8 hours; (2) adding an acidic catalyst to a reactor 2 filled with deionized water to prepare an acidic catalyst solution, wherein the catalyst solution is prepared at a temperature of 25 to 50° C., a stirring speed of 100 to 500 rpm, a time of 5 to 10 minutes, and a pH value of 2 to 5; after stirring evenly, adding a trialkoxysilane monomer to carry out a hydrolysis reaction under acidic conditions at a temperature of 25 to 50° C., a stirring speed of 100 to 500 rpm, and a time of 45 to 60 minutes; (3) While carrying out step (1), add dialkoxysilane monomer to the reaction kettle 3 filled with deionized water, and carry out hydrolysis reaction under neutral conditions at a temperature of 25 to 50° C., a stirring speed of 100 to 500 rpm, and a time of 30 to 60 min; (4) adding a basic catalyst to reactor 2 and reactor 3 respectively to cause a condensation reaction at a temperature of 25 to 50° C., a stirring speed of 100 to 300 rpm, and a time of 5 to 45 min; (5) mixing the reactants in reactor 2 and reactor 3 to allow the organosilicon microspheres formed in reactor 2 to react with the organosilicon chain polymer formed in reactor 3; (6) Finally, the silanol containing carbon-carbon double bonds that has been hydrolyzed in reactor 1 is added to the system for end-capping.

2. The method for preparing hydrophilic elastic micron-sized monodisperse organosilicon microspheres according to claim 1, characterized in that: The organic solvent in step (1) is methanol, ethanol, tetrahydrofuran, acetone, etc., and the ratio of the organic solvent to deionized water is (5-30):

100. The acidic catalyst is any one or more of acetic acid, citric acid, oxalic acid, dilute sulfuric acid, and hydrochloric acid mixed in any proportion, and the ratio of the organic solvent to deionized water is (0.01-5):

100. The monomer containing a carbon double bond is any one or more of dimethylvinylmethoxysilane, dimethylvinylethoxysilane, and tetramethyldivinyldisiloxane mixed in any proportion, and the ratio of the organic solvent to deionized water is (0.01-1):

100.

3. The method for preparing hydrophilic elastic micron-sized monodisperse organosilicon microspheres according to claim 1, characterized in that: The acidic catalyst in step (2) is any one or more of acetic acid, citric acid, oxalic acid, dilute sulfuric acid, and hydrochloric acid mixed in any proportion, and the ratio of the acidic catalyst to deionized water is (0.01-5):

100. The trialkoxysilane monomer is any one or more of methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, and ethyltriethoxysilane mixed in any proportion, and the ratio of the acidic catalyst to deionized water is (5-20):

100.

4. The method for preparing hydrophilic elastic micron-sized monodisperse organosilicon microspheres according to claim 1, characterized in that: The dialkoxysilane monomer in step (3) is any one or more of dimethyldimethoxysilane and dimethyldiethoxysilane mixed in any proportion, and the ratio of the dialkoxysilane monomer to deionized water is (1-10):

100.

5. The method for preparing hydrophilic elastic micron-sized monodisperse organosilicon microspheres according to claim 1, characterized in that: The alkaline catalyst in step (4) is any one or more of ammonia water, sodium hydroxide aqueous solution, ethanolamine aqueous solution, and triethanolamine aqueous solution mixed in any proportion, and the ratio of the alkaline catalyst to deionized water is (0.01-2):

100.

6. The method for preparing hydrophilic elastic micron-sized monodisperse organosilicon microspheres according to claim 1, characterized in that: In the step (4), a basic catalyst is added to the reactor 2 to carry out the reaction.

7. The method for preparing hydrophilic elastic micron-sized monodisperse organosilicon microspheres according to claim 6, characterized in that: The alkaline catalyst is 1% sodium hydroxide aqueous solution or ammonia water, the reaction temperature is 25 to 35 minutes, the stirring speed is 100 to 200 rpm, and the time is 5 to 15 minutes.

8. The method for preparing hydrophilic elastic micron-sized monodisperse organosilicon microspheres according to claim 6, characterized in that: The alkaline catalyst is a 1% ethanolamine aqueous solution or a 1% triethanolamine aqueous solution, the reaction temperature is 25-40° C., the stirring speed is 100-200 rpm, and the reaction time is 15-30 minutes.

9. A hydrophilic elastic micron-sized monodisperse organosilicon microsphere, characterized in that: It is prepared by the method according to any one of claims 1 to 8.

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