KR101550339B1 - Hybrid particle and manufacturing method of the same - Google Patents

Abstract

The present invention relates to an organic-inorganic composite particle having a particle size distribution of 30 microns or less and a method for preparing the same, wherein the mixture of an inorganic substance and a polymeric monomer is emulsified as a water- The reaction product was polymerized to obtain an organic-inorganic composite particle. Such a polymerization method makes it possible to add a higher content of inorganic material than conventional suspension polymerization, and it is possible to produce inorganic or organic composite particles having a high dispersion stability of 30 microns or less even if a relatively low stirring speed and a small amount of a polymerization stabilizer are used Respectively.

Description

TECHNICAL FIELD [0001] The present invention relates to an organic-inorganic composite particle,

The present invention relates to a method for producing stable organic / inorganic hybrid polymer particles having a size of 30 microns or less and excellent particle size distribution through suspension polymerization, and a composite particle produced by the method. More particularly, the present invention relates to an organic / inorganic composite particle prepared by introducing a polymeric dispersion stabilizer dissolved in an aqueous solution into an inorganic / monomer / polymer mixture and emulsifying the mixture by stirring to suspend the dispersion in a dispersion solvent, .

To prepare the organic-inorganic hybrid particles through suspension polymerization, the dispersion stabilizer is dissolved in a conventional dispersion solvent, the monomer is added thereto, the monomer droplets are pulverized by mechanical agitation, suspended and then polymerized to obtain spherical dispersion Were prepared.

For example, (1) a method of dispersing monodisperse seed particles having a linear polymer structure in a dispersion solvent, followed by dispersing (2) a method in which a monomer is dispersed in a reaction solvent in which a stabilizer is dissolved and then the liquid droplets are suspended and stirred to effect polymerization; (3) a method in which a polymer is dissolved in a compatible solvent, And then dispersing the mixture to prepare particles.

However, this method has a problem in that it is difficult to effectively produce an organic-inorganic composite particle of 30 microns or less. In detail, in the method (1), it is difficult to add an inorganic substance to the surface of the particles because it is difficult to add the inorganic substance in the polymerization process. In the method (2), if the stirring speed and the stabilizer are not added, The aggregation phenomenon occurs and the degree of monodispersity is greatly decreased. In the method (3), the particle yield is low and it is difficult to remove the compatible solvent used after the reaction. The method (2) is most commonly applied to produce organic / inorganic composite particles. However, when a metal and an inorganic additive is introduced into a monomer, a large amount of an additive dispersed together with the monomer in the polymerization step escapes from the monomer to the dispersed solvent during polymerization. To control this effectively, a large amount of polymer is dissolved in the monomer, Lt; RTI ID = 0.0 > drop < / RTI > of the additive in the monomer droplets. However, in this process, the viscosity of the monomer droplet is increased by the dissolved polymer, so that it is difficult to control the particle size to 30 microns or less and the particle size distribution of the produced particles is wide.

Korean Patent Registration No. 10-0572013

Therefore, there has been a demand for a method for producing stable organic / inorganic composite particles of less than 30 micrometers by a simple and simple method. However, until now, a suspension polymerization method for producing such composite particles has not been known.

Accordingly, the present invention aims at overcoming the disadvantages of the conventional suspension polymerization method and manufacturing an organic-inorganic composite particle by a more easy method.

      Disclosure of Invention Technical Problem [7] The present invention is to solve the problems of conventional suspension polymerization, and is characterized in that the monomer is pulverized in the process of dispersing the dispersant in the monomer into the reaction solvent by emulsification before introduction into the reaction medium through direct introduction of the dispersant in the monomer.

The method of the present invention can provide an organic / inorganic composite particle having a particle size of 30 microns or less and excellent monodispersity even at a low stirring speed and a small dispersant content.

1 is an optical microscope photograph of an organic / inorganic composite particle obtained by the method of the present invention.
2 is an optical microscope image of an organic / inorganic composite particle obtained by conventional suspension polymerization.

The organic-inorganic composite particles having an excellent particle size distribution of 30 microns or less according to the present invention are prepared using a suspension polymerization method using a radical polymerizable monomer.

In the present invention, unlike the conventional suspension polymerization method, a dispersion stabilizer dissolved in an aqueous solution is directly introduced into a monomer, the monomer is previously emulsified, put in a dispersion solvent, and then suspended and polymerized.

When such a monomer mixture is dispersed in a dispersion solvent, the dispersion medium in the mixture is dispersed in the monomer as a dispersion solvent, and at the same time, the monomer droplet is effectively pulverized even under a relatively low stabilizer content and stirring speed conditions and suspended in a monomer droplet of 30 micro- Lt; / RTI >

Specifically, the method for producing an organic-inorganic composite particle according to the present invention comprises a first step of dissolving a polymerized polymer, an inorganic substance and an initiator in a monomer, then adding a dispersion stabilizer completely dissolved in an aqueous solution thereto and emulsifying the dispersion stabilizer, In which the emulsified monomer is dispersed in a reaction solvent, suspended, and polymerized by heating at a temperature not lower than the reaction start temperature.

The first step is a step of pre-emulsifying the monomer. After the polymeric polymer, the functional inorganic additive and the initiator are completely dissolved in the radical polymerizable monomer, the water-soluble stabilizer dissolved in the water is added thereto, and the monomer mixture is stirred with the stabilizer And emulsifying it.

The polymeric polymer is dissolved in the monomer to increase the viscosity of the monomer, thereby preventing the inorganic additive from escaping into the reaction medium during the dispersion and polymerization and effectively dispersing the monomer droplet in a micro-dispersion. The type of the polymeric monomer is not limited, Such as butadiene, polymethyl methacrylate, and polystyrene, or a combination thereof. The amount of the solvent used is preferably 1 to 40 parts by weight based on 100 parts by weight of the total amount of the monomers.

 The stabilizer is mixed with the monomer in the state of being dissolved in the aqueous solution and dispersed in an emulsified state in the monomer before polymerization. When the stabilizer is dispersed in the aqueous dispersion solvent, the monomer droplets are dispersed in the reaction solvent And is pulverized to pulverize monomer droplets to 30 microns or less. There is no limitation on the kind, but it is preferable to use one kind of polyvinyl alcohol or polyvinyl pyrrolidone which is completely dissolved in water phase or a mixture thereof. The amount of the stabilizer to be used is preferably 0.75 to 5 parts by weight based on 100 parts by weight of the total amount of the monomer and the polymer dissolved therein.

 The functional additive imparts functional properties not possessed by conventional polymers such as heat, electrical conductivity and magnetism to the polymer particles, and it is preferable that the functional additives have particles and rod shapes such as silver, copper, CNT, and graphite, , And it is preferable that the particle state has a size of 1 micron or less. If it is larger than this, the final size may increase or aggregation of the polymer particles may occur during polymerization. The functional additive is preferably used in an amount of 1 to 30% by weight based on 100 parts by weight of the total amount of the monomer and the polymer dissolved therein.

In the second step, the stabilizer dissolved in the aqueous solution in the first step is dispersed in a dispersion solvent, and the stabilized emulsion stabilized in the monomer is dispersed in the aqueous reaction medium through stirring to disperse the monomer into a pulverized suspension A small amount of water phase in a hydrophobic monomer is changed from an emulsified state to an excessive water phase to cause the monomer to be pulverized according to an abrupt phase change and suspension polymerized.

The suspension polymerization is preferably carried out at a temperature of 40 to 90 占 폚. The reaction rate varies depending on the initiator, the reaction temperature and the content of the functional additive, and usually takes 6 to 24 hours. The size of the polymer particles is usually 0.8 to 30 mm according to the size of the functional additive and the viscosity of the monomer and the concentration of the emulsified stabilizer. The particle size distribution of the produced organic / inorganic composite particles can be confirmed by using an optical microschope.

Hereinafter, the constituent components used in the present invention will be specifically described.

(1) Monomer

The monomers usable in the production of the organic / inorganic hybrid polymer particles of the present invention are not particularly limited.

Specific examples of the monomers that can be used include styrene, p-methylstyrene, m-methylstyrene, p-ethylstyrene, m-ethylstyrene, p-chlorostyrene, m-chlorostyrene, Aromatic vinyl monomers of methylstyrene, styrenesulfonic acid, pt-butoxystyrene, mt-butoxystyrene, fluorostyrene, alphamethylstyrene, vinyltoluene and chlorostyrene; Acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate, stearyl (Meth) acrylate, hexafluoroisopropyl methacrylate, perfluoroalkyl acrylate, hexafluorobutyl methacrylate, hexafluorobutyl methacrylate, hexafluoroisopropyl methacrylate, perfluorooctyl methacrylate, (Meth) acrylate monomers such as octafluorophenyl methacrylate; And unsaturated carboxylic acids such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl ether, allyl butyl ether, allyl glycidyl ether, (meth) acrylic acid and maleic acid, alkyl (meth) acrylamide, (meth) acrylonitrile Vinyl cyanide monomers, and the like. In the present invention, monomers may be used singly or in combination of two or more. In particular, the monomer is preferably a styrene, (meth) acrylate monomer or an aromatic vinyl monomer capable of forming a copolymer thereof.

The amount of the monomer to be used is 20 to 80 parts by weight, preferably 30 to 60 parts by weight based on 100 parts by weight of the total amount of the radical polymerizing monomer, initiator, dispersion stabilizer, aqueous solution and functional inorganic additive to be introduced into the first step.

 (2) Initiators

Examples of the initiator include benzoyl peroxide, lauryl peroxide, cumene hydroperoxide, methyl ethyl ketone peroxide, t-butyl hydroperoxide, t-butyl peroxy-2-ethylhexanoate, t- Peroxides such as ethylhexanoate, and 1,3,3-tetramethylbutylperoxy-2-ethylhexanoate; Azo type reaction initiators such as 2,2'-azobisisobutyronitrile, 2,2'-azobis 2,4-dimethylvaleronitrile, and 2,2'-azobis 2-methylisobutyronitrile; And the like can be used.

The amount of the initiator used in the first step is 0.5 to 5 parts by weight, preferably 1 to 3 parts by weight based on 100 parts by weight of the monomer

(3) Dispersion stabilizer

Examples of the dispersion stabilizer include cellulose derivatives such as methyl cellulose, ethyl cellulose and hydroxypropyl cellulose, polyvinyl alcohol, polyvinyl methyl ether, polyacrylic acid, polyvinyl acetate, polyvinyl pyrrolidone, copolymers of vinyl pyrrolidone and vinyl acetate And polyvinyl pyrrolidone, polyvinyl alcohol, and the like. The stabilizer to be used is 0.75 to 5 parts by weight, preferably 2 to 4 parts by weight, based on 100 parts by weight of the sum of the monomer and polymer added in the above step 1.

In addition, the present invention can be additionally used with conventional additives and conventional additives used in conventional suspension polymerization reactions. Butylaldehyde; Trichlorethylene; Perchlorethylene; A polymerization regulator such as acetaldehyde or mercaptan, a pH adjuster, a crosslinking agent, an anti-scale agent, a surfactant, a dye and a pigment may be added as needed.

≪ Example 1 >

(a) Monomer emulsion

In a 1000 ml four-necked glass reactor equipped with a stirrer, 1 g of benzene peroxide initiator was completely dissolved in 68 g of styrene as a monomer, 2 g of a carbon nanotube as a functional additive was added and dispersed at 500 rpm for 5 minutes by stirring. 30 g of polystyrene was added to the mixture, At 300 rpm for 1 hour to prepare a monomer mixture. 30 g of a polyvinyl alcohol dispersion stabilizer solution dissolved in distilled water at a concentration of 10% was added to the reactor, and the monomer mixture was emulsified by sufficiently stirring at a speed of 500 rpm for 30 minutes at room temperature

During the emulsification, the monomer mixture, which is black by the carbon nanotubes, is emulsified and changed to gray by the fine water droplets generated after the stirring process

(b) Dispersion of monomer mixture

300 g of distilled water as a reaction solvent was added to a 2-liter four-necked glass jacket reactor equipped with a stirrer and a thermostat circulator, and the emulsified monomer mixture was added at room temperature and stirred at 250 rpm. When stirring is carried out, the emulsion-dispersed dispersion stabilizer is dissolved in distilled water in the monomer mixture, and the monomer mixture is finely pulverized in this process. Through this process, a monomer droplet having a size of several to several tens of microns is generated This is because the emulsified water due to the stabilizer in the monomer causes the shear force due to the force to escape out of the monomer. Since the stabilizer polyvinyl alcohol is located at the interface between the monomer and water, the shear force is generated more strongly, The lumps will have a small splitting process. The polyvinyl alcohol continuously remains on the surface of the monomer during the pulverization of the monomer, thereby maximizing the surface stabilizing effect of the particle stabilizer and enhancing the stability of the particle.

(c) polymerization

After confirming that the monomer mixture was pulverized into small monomer droplets by the generation of shear force through the discharge of the emulsified stabilizer therein, the temperature of the reactor was raised to 80 캜 and suspension polymerization was carried out. The prepared polymer particles were washed with distilled water and methanol several times by using a centrifuge to remove unreacted materials and dispersion stabilizer. The dried particles were pulverized through a pulverizer, sieved to obtain a final powder sample, and then the particle size distribution was confirmed using an optical microscope. A photograph is shown in FIG.

The polymer particles prepared after the reaction were CNT-polystyrene functional composite particles having a size ranging from 5 to 20 microns.

≪ Example 2 >

The procedure of Example 1 was repeated except that the functional additive was not added in the monomer emulsification step.

≪ Example 3 >

The procedure of Example 1 was repeated except that the functional additive was used as iron oxide in the carbon nanotubes in the monomer emulsification step.

<Example 4>

The procedure of Example 1 was repeated except that 30 g of the aqueous solution in which the 7% stabilizer was diluted in 30 g of the aqueous solution of 10% polyvinyl alcohol dissolved in the monomer emulsification step was used.

 &Lt; Example 5 >

The procedure of Example 1 was repeated except that the monomer mixture was dispersed in the monomer mixture dispersion step at a stirring speed of 200 rpm to 50 rpm.

&Lt; Comparative Example 1 &

Except that the aqueous solution in which the 10% polyvinyl alcohol dissolved in the monomer emulsification step was not added was dissolved in a dispersing solvent and charged. The prepared polymer particles were washed with distilled water and methanol several times by using a centrifuge to remove unreacted materials and dispersion stabilizer. The dried particles were pulverized through a pulverizer, sieved to obtain a final powder sample, and then the particle size distribution was confirmed using an optical microscope. A photograph is shown in FIG.

The polymer particles prepared after the reaction were CNT-polystyrene functional composite particles having a size ranging from 500 to 2,000 microns.

&Lt; Comparative Example 2 &

The procedure of Example 1 was repeated except that 30 g of the aqueous solution of 10% polyvinyl alcohol dissolved in the monomer emulsification step was dispersed in the reaction solvent instead of the monomer mixture.

&Lt; Comparative Example 3 &

      The procedure was the same as in Example 1 except that the polymer was not dissolved in the monomer in the monomer emulsification step.

The experimental results are shown in Table 1. Table 1 shows comparisons of voiding according to additive content.

Functional additive PS content in monomer mixture (%) PVA content /
Monomer mixture
(%) PVA dispersion location Within the particle
Additive content (% / monomer)
rpm Size (mm) Example 1 CNT 30 3 Inside monomer 2 200 5-20 Example 2 none 30 3 Inside monomer 0 200 1 to 7 Example 3 Iron oxide 30 3 Inside monomer 2 200 3 to 10 Example 4 CNT 30 2.1 Inside monomer 2 200 10-25 Example 5 CNT 30 3 Inside monomer 2 50 5-20 Comparative Example 1 CNT 30 0 Dispersed solvent 2 200 500 ~ 2000 Comparative Example 2 CNT 30 3 Inside monomer 2 200 100-1000 Comparative Example 3 CNT 0 3 Inside monomer 0.8 200 1000-3000

In the present invention, by directly emulsifying the aqueous phase stabilizer in the monomer mixture, the viscosity of the monomer mixture is lowered and most of the stabilizer is brought to the surface of the monomer, thereby increasing the dispersion stabilizing effect and greatly increasing the monomer crushing effect. It is possible to manufacture organic / inorganic hybrid polymer particles having a size of 30 microns or less at a relatively low stabilizer concentration and stirring speed as compared with the suspension polymerization method in which a monomer mixture is polymerized by dissolving a stabilizer in a conventional dispersion solvent and then pulverizing the monomer mixture by stirring. In addition, it is possible to solve the problem of increase in particle size and decrease in dispersion in the production of composite particles, which is a problem presented in the conventional suspension polymerization.

According to the production method of the present invention, it is possible to manufacture particles with a particle size of 30 microns or less even under conditions of high inorganic content and high monomer viscosity, and thus can be applied to functional fields in which heat and electric conductivity desired by the user are controlled.

Claims (5)

A first step of dissolving a styrene-based polymer, an inorganic substance and an initiator in a styrene-based monomer, and then emulsifying an aqueous solution containing the polyvinyl alcohol stabilizer dissolved therein;
And a second step of dispersing and emulsifying the monomer mixture emulsified in the first step in an aqueous phase, followed by suspension polymerization. The method for producing an organic-inorganic composite particle according to claim 1, wherein the content of the stabilizer is 0.75 to 5 parts by weight per 100 parts by weight of the total amount of the polymer and the monomer mixture. delete delete The method for producing an organic / inorganic composite particle according to claim 1, wherein the inorganic material is selected from the group consisting of iron oxide, silver, copper, CNT and graphite.

Images