JP3605389B2 - Method for producing polyorganosilsesquioxane fine particles - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a novel method for producing polyorganosilsesquioxane fine particles, and more particularly to a method for producing spherical polyorganosilsesquioxane fine particles by a simple production method.
[0002]
[Prior art]
As a method for obtaining fine particles of polyorganosilsesquioxane, a method of hydrolyzing and condensing organotrichlorosilane or organotrialkoxysilane is known.However, since organotrialkoxysilane is produced from organotrichlorosilane, It is clear that the production can be performed at lower cost by using organotrichlorosilane as a raw material.
[0003]
[Problems to be solved by the invention]
However, since the hydrolysis reaction of organotrichlorosilane is extremely violent, it is difficult to control the reaction. For this reason, the conventional one has been taken out as irregular coarse particles, and it has been difficult to obtain spherical fine particles. Among them, Japanese Patent Application Laid-Open No. Hei 6-179751 discloses a method of synthesizing spherical polyorganosilsesquioxane fine particles by adding organotrichlorosilane to a saturated aqueous hydrogen chloride solution and performing hydrolysis and condensation. According to this method, spherical fine particles having excellent fluidity can be produced using organotrichlorosilane. However, since saturated hydrogen chloride water is used as a reaction solvent, problems remain in terms of safety, corrosion of equipment, and the like. Have been.
[0004]
[Means for Solving the Problems]
The present invention relates to a method for producing spherical polyorganosilsesquioxane fine particles that solves such disadvantages and drawbacks, and comprises adding organotrichlorosilane, which is a raw material, to a water-soluble solvent serving as a reaction solution, and performing hydrolysis and when condensing, which was characterized by adding an alkali to the reaction solution in the same time, by doing so, obtain the knowledge polyorganosilsesquioxane particles having a spherical particle surface is obtained, which Based on the above, the present invention has been completed.
[0005]
[Action]
The present invention is added to a water-soluble solvent comprising a organotrichlorosilane and reaction solvent, time of hydrolysis and condensation, the production of polyorganosilsesquioxane particles characterized by adding an alkali to the reaction solution in the same time By adding the alkali simultaneously, the pH in the reaction solution is controlled, whereby the synthesis of spherical polyorganosilsesquioxane fine particles in most solvent regions from acidic to alkaline can be achieved. Will be possible.
[0006]
In this case, the polyorganosilsesquioxane synthesized in the region where the liquidity of the reaction solution is acidic has a relatively low degree of polymerization, whereas the polyorganosilsesquioxane synthesized in the alkaline region is used. The properties of the polyorganosilsesquioxane obtained differ depending on the liquid property, such as that the polymer has a high degree of polymerization. In other words, in order to obtain polyorganosilsesquioxane fine particles having high thermal stability and a high degree of polymerization, it is necessary to change the liquidity of the reaction solution from a neutral to an alkaline range, and it is also necessary to dissolve the solvent in a solvent or the like. In order to obtain a polyorganosilsesquioxane having a low degree of polymerization easily, it is necessary to adjust the liquid property of the reaction solution from a neutral to an acidic range. And the degree of polymerization of the resulting polyorganosilsesquioxane can be controlled. Alternatively, spherical organosilsesquioxane fine particles having a high degree of polymerization can be obtained by adding an alkali after the reaction in an acidic region and making the pH in the reaction solution alkaline.
[0007]
In the present invention, the organotrichlorosilane as a raw material is represented by the general formula RSiCl ₃ (R represents an alkyl group, an alkenyl group, and an aryl group). Examples of the alkyl group include those having 1 to 8 carbon atoms such as a methyl group, an ethyl group, and a propyl group. Examples of the alkenyl group include those having 2 to 8 carbon atoms, such as a vinyl group, an allyl group, and a propenyl group . Furthermore, examples of the aryl group include a phenyl group.
In the above alkyl group, alkenyl group and aryl group, some of the hydrogens may be replaced by other organic groups, and they may be used as a mixture of two or more.
Further, even if organochlorosilane such as R ₂ SiCl ₂ or R ₃ SiCl is contained in the organotrichlorosilane, it can be used.
[0008]
The water-soluble solvent used as the hydrolysis reaction solution in the present invention can be used in most of the pH range from the acidic range to the alkaline range, but water is particularly preferable.
Alkali species used for adjusting the pH of the water-soluble solvent to be the reaction solution generally include hydroxides, oxides, carbonates and organic nitrogen oxides of Group Ia metals and Group IIa metals, and ammonia. Examples of the acidic species include inorganic acids such as hydrochloric acid and sulfuric acid, and water-soluble organic acids such as formic acid and acetic acid. These acids or alkalis may be used as a mixture of two or more. In addition, even if a water-soluble organic solvent, a surfactant, a polymer dispersant, and the like are contained, they can be used.
[0009]
As the alkali for addition in the present invention, hydroxides, oxides, carbonates and organic nitrogen oxides of metals belonging to Group Ia and Group IIa of the Periodic Table are generally used, and these alkalis are used alone. Alternatively, a mixture of two or more types can be used.
The above-mentioned alkali for addition is preferably used as an aqueous alkali solution mixed with water, and this alkali aqueous solution may be used even if it contains a water-soluble organic solvent, a surfactant, a polymer dispersant, or the like. it can.
[0010]
In the present invention, when adding the organotrichlorosilane to a water-soluble solvent to be the reaction solution, simultaneously adding the alkali for addition into the reaction solution, in order to precipitate spherical polyorganosilsesquioxane fine particles, When the above-mentioned organotrichlorosilane is added to the reaction solution, it is desirable to use an addition method that facilitates diffusion of the organotrichlorosilane into the reaction solution.
The amount of organo trichlorosilane, the reaction solution 1 part by weight, it is preferred that the organotrichlorosilane than 0.1 part by weight, the proportion of the irregular-sized coarse large particles when any more addition amount Increase.
Further, simultaneous addition of alkali to the reaction solution is performed continuously, intermittently, by pH control, or the like.
[0011]
The stirring of the reaction solution in the present invention is preferably performed as strong as possible because the ratio of irregularly shaped coarse particles increases when the stirring is gentle, and the installation of baffles and the like is also effective.
Further, the reaction solution temperature in the present invention can be selected from the range of 0 ° C. to 60 ° C., preferably from 0 ° C. to 40 ° C., in which temperatures above the proportion of amorphous coarse large particles is increased .
[0012]
The reaction according to the present invention proceeds continuously, and the reaction solution slurry is taken out from the reaction vessel so that the volume of the reaction solution becomes substantially constant, thereby producing continuous spherical polyorganosilsesquioxane fine particles. Is also possible.
[0013]
Also in the reaction in the above method, it is necessary to adjust the ratio of the amount of organotrichlorosilane in the reaction solution to 0.1 part by weight or less based on 1 part by weight of the reaction solution .
[0014]
The spherical polyorganosilsesquioxane microparticles thus produced are then aged, filtered, separated and washed with water or an organic solvent, dried and, if necessary, crushed to obtain a spherical polyorganosilsesquioxane fine particle. Oxane fine particles are obtained.
The obtained fine particles are spherical polyorganosilsesquioxane fine particles. According to the present invention, spherical polyorganosilsesquioxane fine particles can be efficiently produced from organotrichlorosilane by a simple production method.
[0015]
[Experimental example]
Hereinafter, the method of the present invention will be described with reference to experimental examples, but it is needless to say that the present invention is not limited to these examples.
[0016]
[Experimental example 1]
A stirrer and a thermometer were attached to a 500 ml (milliliter) reaction vessel, 250 ml of water serving as a reaction solution was added to the reaction vessel, and the reaction vessel was stirred at 500 rpm (rotation per minute). 12.5 g of methyltrichlorosilane was added at a supply rate of 1.5 g / min (gram per minute) by a pump, and a 25% aqueous ammonia solution was added at a rate of 2.1 g / min. At the same time as the completion of the supply of methyltrichlorosilane, the supply of the aqueous ammonia solution was stopped. The addition ratio (mol ratio) = (ammonia / chlorine in methyltrichlorosilane) was 1.03, and the liquidity of the reaction solution was alkaline. Then, after aging at room temperature for 1 hour, filtration, washing and drying were performed to obtain white particles. These particles were polymethylsilsesquioxane fine particles having a high degree of polymerization and high stability to heat and solvents. Observation of the obtained particles with an electron microscope revealed spherical fine particles (see the electron micrograph in FIG. 1).
[0017]
[Comparative example]
A stirrer and a thermometer were attached to a 500 ml reaction vessel, and 18 g of a 25% aqueous ammonia solution serving as a reaction solution and 232 g of water were added to the reaction vessel. The reaction vessel was kept at 20 ° C. while stirring at 500 rpm. 12.5 g of methyltrichlorosilane was added to the reaction solution at a feed rate of 1.5 g / min. The addition ratio (mol ratio) = (ammonia / chlorine in methyltrichlorosilane) was 1.06, and the liquidity of the reaction solution was alkaline. After completion of the supply, the mixture was aged at room temperature for 1 hour, and then filtered, washed with water and dried to obtain white particles. Although these particles were polymethylsilsesquioxane particles, as observed by an electron microscope, they had many irregular aggregates and could not be taken out as a powder having excellent fluidity (see the electron microscope in FIG. 2). See photo).
[0018]
[Experimental example 2]
A stirrer and a thermometer were attached to a 500 ml reaction vessel, 250 ml of water serving as a reaction solution was added to the reaction vessel, and the reaction vessel was kept at a constant temperature of 20 ° C. while stirring at 500 rpm. Was added at a feed rate of 1.5 g / min, and at the same time, a 25% aqueous ammonia solution was added at a rate of 1.8 g / min. At the same time as the completion of the supply of methyltrichlorosilane, the supply of the aqueous ammonia solution was stopped. The addition ratio (mol ratio) = (ammonia / chlorine in methyltrichlorosilane) was 0.88, and the liquidity of the reaction solution was acidic. Then, after aging for 1 hour at room temperature, filtration and washing were performed to obtain white particles. These particles were polymethylsilsesquioxane, and as a result of observation with an electron microscope, were spherical fine particles. This powder was a low-polymerization degree polymethylsilsesquioxane having a property of being easily dissolved in various solvents and having a property of melting when heated.
[0019]
[Example 3]
After the addition of methyltrichlorosilane was completed, 2.7 g of a 25% aqueous ammonia solution was further added to the reaction solution prepared by simultaneously adding methyltrichlorosilane and an aqueous ammonia solution in the same manner as in Experimental Example 2. The total addition ratio (mol ratio) = (ammonia / chlorine in methyltrichlorosilane) was 1.04. Then, after aging at room temperature for 1 hour, filtration, washing and drying were performed to obtain white particles. The liquid property of the reaction solution during aging was alkaline. The particles obtained were polymethylsilsesquioxane particles having a high degree of polymerization and high stability to heat and solvents. Observation of the obtained powder with an electron microscope revealed spherical fine particles.
[0020]
[Effects of the present invention]
ADVANTAGE OF THE INVENTION According to the method of this invention, spherical polyorganosilsesquioxane microparticles | fine-particles can be manufactured efficiently from an organotrichlorosilane by a simple method with little corrosion etc. of a manufacturing apparatus.
[Brief description of the drawings]
FIG. 1 is an electron micrograph of polymethylsilsesquioxane particles produced in Experimental Example 1.
FIG. 2 is an electron micrograph of polymethylsilsesquioxane particles produced in a comparative example.

Claims (1)

Was added organotrichlorosilane in an aqueous solvent as a reaction solution, when to hydrolysis and condensation, when adding the organotrichlorosilane in the reaction solution within a characterized by adding an alkali to the reaction solution in the same time Of producing polyorganosilsesquioxane fine particles.

Images