JP3616909B2 - Method for producing monodispersed solid fine particles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing monodispersed solid fine particles used for pharmaceuticals, cosmetics, spacers for liquid crystal display devices, standard particles, analytical fillers, carriers for diagnostic agents, various labeling materials and the like.
[0002]
[Prior art]
Conventionally known methods for producing solid fine particles include suspension polymerization and emulsion polymerization. The suspension polymerization method is a method of synthesizing solid fine particles by polymerizing the dispersed phase of the emulsion, and the emulsion polymerization method is a method of synthesizing solid fine particles by performing a polymerization reaction in a surfactant micelle.
[0003]
In such a suspension polymerization method, it is difficult to produce monodispersed solid fine particles because the particle size distribution of the produced solid fine particles depends on the particle size distribution of the emulsion before polymerization. The particle size of solid fine particles that can be usually synthesized by emulsion polymerization is about 0.1 μm, and it is difficult to synthesize solid fine particles of several μm or more.
[0004]
[Problems to be solved by the invention]
An object of the present invention is to provide a method for producing monodispersed solid fine particles having a particle size of several μm or more in view of the above-described present situation.
[0005]
[Means for Solving the Problems]
The present invention relates to a method for producing monodispersed solid fine particles obtained by polymerizing a reactive monomer, and (1) pressurizing the composition for a dispersed phase containing the reactive monomer, (2) a step of producing a suspension of solid fine particles by polymerizing the emulsion, and (3) removing the continuous phase from the suspension. A method for producing monodispersed solid fine particles comprising a step of collecting solid fine particles.
The present invention is described in detail below.
[0006]
The method for producing monodispersed solid fine particles of the present invention is obtained by polymerizing a reactive monomer.
The reactive monomer is not particularly limited as long as it can produce an emulsion and produce solid fine particles by polymerization, and examples thereof include a polymerizable monomer having a carbon-carbon double bond, and a solid What is necessary is just to select suitably according to the use of microparticles | fine-particles.
[0007]
The method for producing monodispersed solid fine particles of the present invention comprises the steps (1), (2) and (3).
The step (1) is a step of generating an emulsion by pressurizing the composition for the dispersed phase containing the reactive monomer and dispersing the composition for the dispersed phase in the continuous phase through the microchannel.
The composition for dispersed phase containing the reactive monomer may contain components other than the reactive monomer.
[0008]
In the step (1), in order to improve the monodispersity of the solid fine particles, it is preferable to add a surfactant to either or both of the continuous phase and the composition for the dispersed phase.
It does not specifically limit as said surfactant, For example, what is necessary is just to select suitably according to the kind of reactive monomer, the kind of continuous phase, the use of a solid fine particle, etc.
The pressure for pressurizing the composition for a dispersed phase containing the reactive monomer is not particularly limited, and may be appropriately set depending on, for example, the size required for the dispersed phase;
[0009]
The microchannel means a gap having a certain shape in which a dispersed phase composition can be dispersed in a continuous phase to form a dispersed phase.
The microchannel is preferably formed by a large number of gaps having a certain shape because the manufacturing efficiency is improved.
By dispersing the composition for a dispersed phase in a continuous phase through a microchannel, the composition for a dispersed phase can be made into a dispersed phase composed of fine particles (microspheres) having a uniform size in the continuous phase. .
In the step (1), the apparatus for producing the emulsion is not particularly limited, and for example, the apparatus proposed by the present applicant in Japanese Patent Application No. 11-78862 can be used.
[0010]
The step (2) is a step of producing a suspension of solid fine particles by polymerizing the emulsion.
In the step (2), the fine particles forming the dispersed phase can be solidified by polymerizing the emulsion to produce a suspension of solid fine particles.
The method for polymerizing the emulsion is not particularly limited. For example, a method of increasing the temperature after adding a polymerization initiator to the emulsion; the polymerization initiator is dissolved in the composition for dispersed phase in advance (1) A method of increasing the temperature after preparing an emulsion in the process; a method of irradiating light of a specific wavelength using a photopolymerization initiator, and the like can be mentioned. Good.
[0011]
In the above polymerization, it is preferable to perform polymerization after adding a dispersant to the emulsion in order to prevent coalescence of particles during polymerization. Moreover, a dispersing agent can also be added to either or both of the composition for dispersed phase and the continuous phase at the time of emulsion formation in the step (1).
[0012]
The step (3) is a step of recovering solid fine particles by removing the continuous phase from the suspension.
In the step (3), the method for removing the continuous phase from the suspension and collecting the solid fine particles is not particularly limited. For example, a drying method such as a vacuum drying method or a spray drying method can be used. Further, when there is a problem that unreacted monomer, surfactant, dispersant, etc. remain depending on the use of the solid fine particles, it is preferable to wash the solid fine particles by an extraction operation or the like before removing the continuous phase.
[0013]
The method for producing monodispersed solid fine particles of the present invention can produce monodispersed solid fine particles of several μm or more.
The monodispersed solid fine particles can be used for pharmaceuticals, cosmetics, liquid crystal display spacers, standard particles, analytical fillers, diagnostic carrier, various labeling materials, and the like.
[0014]
The present invention 2 is a method for producing a spacer for a liquid crystal display device by polymerizing a reactive monomer, and (1) pressurizing the composition for a dispersed phase containing the reactive monomer, A step of producing an emulsion by dispersing in a continuous phase via a microchannel, (2) a step of producing a suspension of solid fine particles by polymerizing the emulsion, and (3) removing the continuous phase from the suspension. This is a method for producing a spacer for a liquid crystal display device comprising a step of recovering the spacer for a liquid crystal display device as solid fine particles.
[0015]
The method for producing a spacer for a liquid crystal display device of the present invention 2 can be carried out in the same manner as the method for producing monodispersed solid fine particles of the present invention 1.
The spacer for a liquid crystal display device obtained by the method for producing a spacer for a liquid crystal display device of the present invention 2 has a particle size of several μm or more and excellent monodispersibility.
With the liquid crystal display device spacer, a liquid crystal display device having a uniform liquid crystal layer thickness (cell gap) and few defects such as display unevenness can be obtained.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a block diagram showing an outline of the method for producing monodispersed solid fine particles of the present invention in the order of steps.
According to the block diagram, first, a composition for a dispersed phase containing a reactive monomer is prepared. Next, as the step (1), this dispersed phase composition is pressurized, and the above dispersed phase composition is dispersed in a continuous phase such as water via a microchannel, and microchannel emulsification is performed to obtain a monodispersed emulsion. Is generated. Next, as step (2), the monodispersed emulsion is polymerized by heating or the like to form a monodispersed suspension. Thereafter, as step (3), the continuous phase is removed by drying from the monodispersed suspension to recover monodispersed solid fine particles.
[0017]
Below, an example of the apparatus which produces | generates a monodispersed emulsion is demonstrated based on FIGS. Here, FIG. 2 is an overall cross-sectional view of the emulsion generating apparatus, FIG. 3 is an enlarged schematic view of the main part of the same emulsion generating apparatus, and FIG. 4A is a plan view of a substrate in the emulsion generating apparatus. b) is a back view of the substrate in the emulsion generating apparatus, and FIG. 5 is an enlarged perspective view of a microchannel portion.
[0018]
2-5, the emulsion production | generation apparatus connects the main body 1 to the thermostat 2, and can control the temperature of the main body 1 to predetermined | prescribed temperature. And the plate 3 comprised from a glass plate etc. is inserted in one opening of the main body 1, the cover body 4 is inserted in the other opening, and the supply port 5 of the composition (O) for dispersed phases is formed in the center of the cover body 4. The supply port 6 of the continuous phase (W) is formed at a position (upward in the drawing) formed from the center of the lid body 4, and the emulsion (E) is further removed from the center (downward in the figure) of the lid body 4. ) Is formed.
[0019]
A dispersion phase composition reservoir 8 is connected to the supply port 5 of the dispersion phase composition (O) via a pipe, a heater 9 is provided around the pipe, and a continuous phase (W) is supplied. A continuous phase reservoir 10 is connected to the port 6 via a pipe, and a recovery pipe 11 is connected to the outlet 7 for the emulsion (E). Here, the dispersed phase composition reservoir 8 and the continuous phase reservoir 10 can be adjusted in the vertical position, and the pressure acting on the dispersed phase composition (O) and the continuous phase (W ) Can be adjusted respectively.
[0020]
A substrate 12 is disposed in the space between the plate 3 and the lid 4. An opening 13 is formed in the center of the substrate 12, and a protrusion 14 is formed on the front side of the substrate 12 opposite to the plate 3 so as to surround the opening 13 in a rectangular shape. 15, a large number of protrusions 16 are formed on the terrace 15 at regular intervals, and a microchannel 17 is formed between the protrusions 16 and 16.
The dimensions of the microchannel 17 are, for example, a width of 16 μm, a height of 2 μm, and a terrace length of 30 μm. Also, wet etching or dry etching is appropriate as a method for forming the protrusion 14 including the microchannel 17.
[0021]
Further, a partition member 18 such as an O-ring is interposed between the substrate 12 and the lid body 4, and the protrusion 16 is brought into contact with the inside of the plate 3 by the elastic force (elastic force) of the partition member 18. The supply port 5 for the dispersed phase composition (O) is opened in the inner region surrounded by the partition wall member 18, and the continuous phase (W) supply port 6 and the emulsion (E) are removed in the outer region. The outlet 7 is open. A camera 19 connected to the video system is arranged outside the plate 3.
[0022]
The apparatus for producing a monodispersed emulsion is not limited to the above configuration. For example, in the example of FIGS. 1-5, although the plate 3, the cover body 4, and the board | substrate 12 were arrange | positioned in the vertical direction, you may arrange | position these in a horizontal direction. As another device, a substrate is placed in a case, a continuous phase flow path is formed between the substrate and the plate, and a microchannel that opens in a direction intersecting the flow path is formed in the substrate. It is good also as a cross flow type which supplies the composition for dispersed phases from the direction which forms and cross | intersects with respect to the continuous phase which is in a fluid state.
[0023]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.
[0024]
As the composition for the dispersed phase, divinylbenzene in which 25% hydrate of benzoyl peroxide as a radical polymerization initiator was dissolved at a concentration of 2% was used, and 0.3% sodium dodecylbenzenesulfonate aqueous solution was used for the continuous phase. Microchannel emulsification was performed at room temperature. The supply pressure of the composition for a dispersed phase was set to a range of 4.9 to 6.9 kPa (0.05 to 0.07 kg / cm ² ). After 100 parts of the produced emulsion was stirred and mixed with 100 parts of a 2% polyvinyl alcohol solution, the reaction was performed at 90 ° C. Thereafter, the suspension was dried to obtain white solid fine particles. The obtained fine particles had an average particle diameter of 16.4 μm and a standard deviation of 1.18 μm.
[0025]
【The invention's effect】
Since the method for producing solid fine particles of the present invention has the above-described configuration, it is possible to produce monodispersed solid fine particles having a particle size of several μm or more that can be used for spacers for liquid crystal display devices.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an outline of the present invention in the order of steps.
FIG. 2 is an overall view of an emulsion production apparatus used as an embodiment of the present invention.
FIG. 3 is an enlarged schematic view of the main part of the emulsion production apparatus of FIG.
4 (a) is a plan view of a substrate in the emulsion generating apparatus of FIG. 2. FIG.
(B) is the back view of the board | substrate in the emulsion production | generation apparatus of FIG.
FIG. 5 is an enlarged perspective view of a microchannel portion in the emulsion generating apparatus of FIG. 2;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Emulsion main body 2 Constant temperature bath 3 Plate 4 Lid 5 Dispersion phase composition (O) supply port 6 Continuous phase (W) supply port 7 Emulsion (E) outlet 8 Dispersion phase composition reservoir 9 Heater 10 Continuous phase reservoir 11 Recovery pipe 12 Substrate 13 Opening 14 Projection 15 Terrace 16 Projection 17 Microchannel 18 Partition member 19 Video camera 20 Composition for dispersed phase (O)
21 Continuous phase (W)
22 Microsphere

Claims (4)

A method for producing monodispersed solid fine particles obtained by polymerizing reactive monomers,
(1) Pressurizing a composition for a dispersed phase containing a reactive monomer, and dispersing the composition for a dispersed phase through a microchannel in a continuous phase to which a surfactant has been added to form an emulsion;
(2) A step of preparing a suspension of solid fine particles by polymerizing after stirring and mixing the emulsion with a polyvinyl alcohol solution, and
(3) A method for producing monodispersed solid fine particles, comprising a step of recovering solid fine particles by removing a continuous phase from the suspension. The method for producing monodispersed solid fine particles according to claim 1, wherein the surfactant is sodium dodecylbenzenesulfonate. An emulsion generating apparatus in which a constant temperature bath capable of controlling the main body temperature to a predetermined temperature is provided in the main body, and a heater is provided around a pipe for supplying the dispersed phase composition containing the reactive monomer to the main body. The method for producing monodispersed solid fine particles according to claim 1 or 2, which is used. The spacer for liquid crystal display elements which uses the manufacturing method of the monodispersed solid particulates of any one of Claims 1-3.

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