JP2017031289A - Organic compound fine particle production method and fine particle production apparatus - Google Patents

Abstract

[Problem] To provide a method for producing fine particles of an organic compound, which can produce fine particles with a mean particle size on the order of 10 to 100 nm, with small variance and high uniformity. [Solution] This method for producing fine particles made of an organic compound is characterized by having a step of irradiating a medium with light while polymerizing a monomer in the medium. (Selected Figure)

Description

  The present invention relates to a fine particle production method and a fine particle production apparatus for producing fine particles of an organic compound.

  For example, in order to improve the chemical activity and dispersion stability of an organic compound, or to obtain unprecedented material properties, the organic compound may be made into fine particles.

  Such fine particles of an organic compound are desired to be uniform fine particles having not only an average particle size on the order of 10 to 100 nm but also a small variation in particle size distribution.

  As a conventional method for producing fine particles of an organic compound, there is a method in which a powder of an organic compound pulverized in advance is dispersed in a dispersion medium and laser light is irradiated to the dispersion medium as disclosed in Patent Document 1. . The wavelength and intensity of the laser light used in this method is such that the organic compound powder in the dispersion medium is not chemically decomposed, and the local temperature rise occurs in the organic compound powder when irradiated with the laser light. Is set to a value. By doing in this way, the powder of the organic compound in the dispersion medium is pulverized by thermal stress and finally has a predetermined average particle size and variation in particle size distribution.

  In addition, as shown in Non-Patent Document 1, the average particle size of the polymerized polystyrene particles can be controlled by adjusting the concentration of the styrene monomer in the dispersion medium when forming the polystyrene particles by the emulsion polymerization method. There is also a way to do it.

  However, the method disclosed in Patent Document 1 can obtain fine particles of an organic compound having a particle size distribution of the order of 100 μm, but it is difficult to obtain fine particles of the order of nm.

  In addition, even with the method disclosed in Non-Patent Document 1, a particle size distribution of the order of 100 nm can be obtained for the fine particles of the organic compound, but an average particle size of the order of 10 nm cannot be realized. In any method, the dispersion of the particle size distribution is large, and it is difficult to obtain organic compound fine particles having desired uniformity.

Japanese Patent No. 4457439

Particle size control of polystyrene particles by emulsion polymerization https://www.kanagawa-iri.jp/wp-content/uploads/filebase/koryukai/2012/3PS-30.pdf

  The present invention provides a fine particle production method and a fine particle production apparatus capable of obtaining fine particles of an organic compound having an average particle size on the order of 10 to 100 nm and having a small variation in particle size distribution and high uniformity. Objective.

  That is, the method for producing fine particles of an organic compound according to the present invention is a method of producing fine particles comprising an organic compound, and includes a step of irradiating the medium with light while polymerizing monomers in the medium. Features.

  With such a method, the average particle size of the fine particles of the organic compound can be on the order of nm, and the variation in the particle size distribution can be reduced to achieve high uniformity. This is expected to be caused by the fact that the polymerization reaction rate of the monomer can be decreased as a whole by irradiating the medium with light.

  As the light suitable for controlling the dispersion of the particle size distribution while controlling the average particle size of the fine particles of the organic compound formed by polymerization of the monomer in the order of nm, the peak wavelength of the light has a wavelength of visible light. The thing in a wavelength range is mentioned.

  In order to reduce the distribution width of the particle size distribution of the fine particles and make the effect of obtaining highly uniform fine particles remarkable, the peak wavelength of the light only needs to be in the wavelength range of red light.

  As another embodiment in which the dispersion of the particle size distribution can be reduced while the average particle size of the fine particles of the organic compound is on the order of 10 nm, the peak wavelength of the light is in the wavelength range of ultraviolet light. Is mentioned.

  In order to prevent the chemical composition of the monomer or the organic compound generated by polymerization from being changed by the light and to increase the composition purity of the fine particles, the light may be incoherent light.

  As an example of the monomer in which the effect of the present invention is remarkable, the monomer is styrene, which can produce polystyrene fine particles.

  An apparatus for producing fine particles of an organic compound for producing fine particles of an organic compound having an average particle size on the order of 10 to 100 nm and having a very small variation in the particle size distribution, the monomer in the medium An organic compound fine particle manufacturing apparatus characterized by irradiating the medium with light while polymerizing the medium may be used.

  As described above, the organic compound fine particle production method according to the present invention has an average particle diameter of 10 to 100 nm generated by a novel process that does not exist in the prior art of irradiating light during the polymerization of the monomer. , The dispersion can be reduced and uniform. This is presumably because when the light is irradiated during the polymerization of the monomer, the polymerization rate becomes slow due to some interaction with the polymerization reaction, and as a result, the particle diameters are easily aligned.

The typical sectional view of the device for manufacturing the particulates of the organic compound used in the example. 4 is an electron micrograph of polystyrene fine particles obtained in Example 1. FIG. 4 is an electron micrograph of polystyrene fine particles obtained in Comparative Example 1. FIG. 4 is an electron micrograph of polystyrene fine particles obtained in Example 2. FIG. 4 is an electron micrograph of polystyrene fine particles obtained in Example 3. FIG.

  An organic compound fine particle production method and fine particle production apparatus according to an embodiment of the present invention will be described. In the fine particle production method of the present embodiment, the organic compound in which fine particles are formed is a polymer produced by polymerizing monomers. Examples of the organic compound include polystyrene, polymethyl methacrylate (PMMA), polylactic acid, and the like. The fine particle production apparatus 100 according to the present embodiment includes a magnetic stirrer 1 that stirs a medium in which a monomer is dispersed, and an LED 2 that irradiates light to the medium and the monomer during the polymerization reaction. . A reflective film made of aluminum is formed on the side and bottom of the magnetic stirrer 1 so that the light emitted from the LED 2 is sufficiently irradiated to the medium and the monomer.

  The fine particle production method of this embodiment includes a step of adding a reaction initiator to a medium containing a monomer to start a polymerization reaction and irradiating light in a state where the polymerization reaction proceeds. More specifically, the light having a predetermined wavelength is irradiated by the LED 2 disposed in the lid portion of the magnetic stirrer 1 while stirring the mixed liquid to which the medium and the reaction initiator are added by the magnetic stirrer 1. It is.

  The medium may be either a solvent or a dispersion medium. For example, an organic solvent may be used, or a dispersion medium such as methanol or water may be used.

  Further, the light emitted from the LED 2 may be light of various wavelengths such as visible light, ultraviolet light, and infrared light. Here, the LED 2 used in the present embodiment emits incoherent light, not laser light. The present invention is not limited to incoherent light, and laser light may be used.

  The light emitted from the LED 2 to the medium is irradiated for a predetermined time from the start of polymerization. Here, with respect to the irradiation time of light, irradiation may be performed until the polymerization is completely completed, or irradiation may be terminated before the polymerization is completely completed. Moreover, light irradiation may be started after a while from the start of polymerization. The light emitted from the LED 2 may be continuous or intermittent.

  In the present embodiment, the polymerization reaction is not limited to that shown in the embodiment, and the present invention can be used to form polymer fine particles produced by various types of polymerization reactions.

  Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

<Production condition 1 of polystyrene fine particles>
In a 1000 ml beaker, 14.8 ml of styrene and water as a dispersion medium are measured to obtain a mixed solution. 0.42 / 20 g / ml-H 2 O of potassium peroxodisulfate (KPS) is added as a polymerization initiator for styrene to this mixture, and the mixture is stirred with a magnetic stirrer 1 while maintaining the mixture at 70 ° C. The stirring speed is maintained at the first predetermined speed.

  In Example 1, polystyrene particles are produced by irradiating the LED 2 with light having a peak wavelength of 625 nm from the start of polymerization. In Comparative Example 1, polystyrene fine particles are produced in the dark state without irradiation with light from the start to the end of polymerization.

<Result 1>
Results 1 are summarized in Table 1. FIG. 2 shows an electron micrograph of the polystyrene fine particles obtained in Example 1. FIG. 3 shows an electron micrograph of polystyrene fine particles obtained in Comparative Example 1.

  As can be seen from the comparison results in Table 1, when the red light is emitted from the LED 2 while the polymerization reaction is proceeding, the average particle size and the variation of the particle size distribution of the polystyrene fine particles are compared with the case where the light is not irradiated. It can be seen that it can be made smaller. Further, as can be seen from FIG. 2, when the polymerization reaction of styrene proceeds while irradiating with red light, the shape of each fine particle is kept substantially spherical and uniform. On the other hand, as can be seen from FIG. 3, when polystyrene fine particles are produced without irradiating light, some of the particles have a large particle size and the shape is distorted out of a sphere.

  For these reasons, the average particle size of the polystyrene fine particles is controlled to the order of 10 nm by irradiating light while the polymerization reaction proceeds as in Example 1, and the variation in the particle size distribution is very small. Thus, the particle diameters of almost all the fine particles can be set to the same 10 nm order.

  Next, another embodiment will be described.

<Production conditions 2 of polystyrene fine particles>
In this embodiment, the amount and temperature of each material and the conditions relating to stirring are different from those of the above-described embodiment. More specifically, 15 ml of styrene and 300 ml of water as a dispersion medium are measured in a 300 ml beaker to obtain a mixed solution. To this mixed solution, 0.2 / 10 g / ml-H 2 O of potassium peroxodisulfate (KPS) is added as a styrene polymerization initiator, and the mixture is stirred with a magnetic stirrer 1 while maintaining the mixture at 80 ° C. The stirring speed is maintained at a second predetermined speed that is slower than the first predetermined speed from the start to the end of the polymerization.

  In Example 2, polystyrene fine particles are produced by irradiating the LED 2 with ultraviolet light having a peak wavelength of 375 nm for 7 hours from the start of polymerization. In Example 3, polystyrene light particles are produced by irradiating the LED 2 with red light having a peak wavelength of 625 nm for 7 hours from the start of polymerization.

<Result 2>
Results 2 are summarized in Table 2. Although the production conditions are different, the production results of polystyrene fine particles in the dark state are also described as reference comparative examples. FIG. 4 shows an electron micrograph of polystyrene fine particles obtained in Example 2. FIG. 5 shows an electron micrograph of polystyrene fine particles obtained in Example 3.

  As can be seen from the comparison results in Table 2, the manufacturing conditions of Example 2 and Example 3 are different from those of Comparative Example 1. Therefore, the dispersion of the particle size distribution is greatly increased while keeping the average particle size in the same order as Comparative Example 1. Reduced and uniform fine particles can be obtained. This can be confirmed from the electron micrographs shown in FIGS.

  From these examples, the average particle size can be controlled to a desired value by changing the production conditions, and the dispersion of the particle size distribution of the fine particles is reduced, and in order to obtain uniform fine particles, polymerization is performed while irradiating with light. It can be seen that the reaction should be continued.

  With the fine particle production method and fine particle production apparatus of the present invention, uniform organic compound fine particles having a small particle size distribution can be obtained by only a simple process while having an average particle size on the order of 10 to 100 nm. The fine particles obtained in this way can be used, for example, as a lost wax for producing pores of an electrode material, or as a chemical material having good reactivity due to the surface area relative to the volume. Become.

DESCRIPTION OF SYMBOLS 100 ... Fine particle manufacturing apparatus 1 ... Magnetic stirrer 2 ... LED

Claims (7)

A method for producing fine particles comprising an organic compound,
A method for producing fine particles of an organic compound, comprising a step of irradiating the medium with light while polymerizing monomers in the medium.   The method for producing fine particles of an organic compound according to claim 1, wherein the peak wavelength of the light is in a visible light wavelength range.   The method for producing fine particles of an organic compound according to claim 1, wherein the peak wavelength of the light is in a wavelength range of red light.   The method for producing fine particles of an organic compound according to claim 1, wherein the peak wavelength of the light is in the wavelength range of ultraviolet light.   The method for producing fine particles of an organic compound according to claim 1, wherein the light is incoherent light.   The method for producing fine particles of an organic compound according to any one of claims 1 to 5, wherein the monomer is styrene, and fine particles of polystyrene are produced. A production apparatus for producing fine particles made of an organic compound,
An apparatus for producing fine particles of an organic compound, wherein the medium is irradiated with light while polymerizing monomers in the medium.