KR100597119B1 - Production of vinyl polymer particles by dispersion polymerization using amphoteric initiator - Google Patents

Abstract

The present invention relates to a method for producing vinyl polymer particles having a uniform particle size distribution by a dispersion polymerization method, and more particularly, using an amphoteric initiator, while reducing the amount of a stereostable agent and having a stable and uniform particle distribution. The present invention relates to a method for producing vinyl polymer beads. In the present invention, a vinyl monomer, a polymerization initiator, and a steric stabilizer are dissolved in a dispersion medium to produce vinyl polymer beads by dispersion polymerization, wherein the amphoteric polymerization initiator is used as the polymerization initiator, and the steric stabilizer is monomer 100. 1 to 5 parts by weight of the vinyl-based polymer beads, characterized in that the particle size distribution (CV) is 5% or less to obtain a spherical polymer beads having a particle size of 0.1 to 20 ㎛ Provided is a method for preparing. According to the present invention, uniform and stable particles having a particle size distribution of 5% or less can be obtained while greatly reducing the amount of the steric stabilizer, which is conventionally used at 10 to 15 parts by weight, based on 100 parts by weight of monomer, to 1 to 5 parts by weight.

Amphoteric initiator, steric stabilizer, dispersion polymerization, vinyl polymer particles

Description

Production Method of Vinyl Polymer Particles Using Amphoteric Initiator in Dispersion Polymerization {Production of Vinyl Polymer Particles by Dispersion Polymerization Using Amphoteric Initiator}

1 is a scanning electron micrograph of the polystyrene particles prepared in Example 1 of the present invention.

2 is a scanning electron micrograph of the polystyrene particles prepared in Example 2 of the present invention.

3 is a scanning electron micrograph of the polystyrene particles prepared in Example 3 of the present invention.

4 is a scanning electron micrograph of the polystyrene particles prepared in Example 4 of the present invention.

5 is a scanning electron micrograph of the polymethyl methacrylate particles prepared in Example 7 of the present invention.

Figure 6 is a scanning electron micrograph of the polymethyl methacrylate particles prepared in Example 8 of the present invention.

7 is a scanning electron micrograph of the polymethyl methacrylate particles prepared in Example 9 of the present invention.

8 is a scanning electron micrograph of the polystyrene particles prepared in Example 10 of the present invention.

9 is a scanning electron micrograph of the polystyrene particles prepared in Example 12 of the present invention.

10 is a scanning electron micrograph of the polystyrene particles prepared in Example 13 of the present invention.

11 is a scanning electron micrograph of the polystyrene particles prepared in Example 18 of the present invention.

12 is a scanning electron micrograph of the polystyrene particles prepared in Comparative Example 1 performed to compare with the polymer particles of the present invention.

Figure 13 is a scanning electron micrograph of the polystyrene particles prepared in Comparative Example 2 carried out to compare with the polymer particles of the present invention.

The present invention relates to a method for producing vinyl polymer particles having a uniform particle size distribution by a dispersion polymerization method, and more particularly, using an amphoteric initiator, while reducing the amount of a stereostable agent and having a stable and uniform particle distribution. The present invention relates to a method for producing vinyl polymer beads.

Dispersion polymerization is carried out under the conditions of using monomers, polymerization initiators, steric stabilizers to help form polymer particles, and organic solvents.In the initial stage of reaction, all reaction components are dissolved in organic solvents and the number of phases is transparent. As the polymerization proceeds, a polymer whose molecular weight increases does not dissolve in the organic solvent, but is precipitated. At this time, a spherical particle is formed in the size of several hundred nm to several tens of micrometers by the steric stabilizer present [K. E. J. Barrett, Dispersion Polymerization in Organic Media, Wiley, Chichester, England, 1975]. The stereostabilizers used in the dispersion polymerization are polyvinylpyrrolidone and cellulose series, which are characterized in that the polymer polymerization is initiated in the stereostabilizer molecule by reacting with radicals generated by the initiator at the beginning of the reaction [Can. J. Chem., 63, 209-216, 1985].

The spherical polymer particles having a size of several μm formed by dispersion polymerization method are standard materials used when testing the instrument, measuring the size and efficiency of filter processing, packing material for chromatography column, support in biochemistry, and biomedical science. It can be applied to various fields of high value-added fields such as microelectronics and information industries such as coating, coating, ink, polymerized toner for radiation, and anisotropic conductive balls.

In the conventional dispersion polymerization method, azo-based and peroxide-based initiators are most widely used as initiators. In addition, in the conventional dispersion polymerization method, particles are generated by the steric stabilizer as mentioned above. In order to prepare spherical particles having a stable and uniform size, a steric stabilizer is used in an amount of 10 to 15 parts by weight based on 100 parts by weight of the monomer. Should [Chem. Eng. J., 78, 211-215, 2000; Macromolecules, 23, 3019, 1990; J. Polym. Sci., Polym. Let. Ed., 23, 103, 1985; J. Polym. Sci. Polym. Chem. Ed., 24, 2995, 1986]. In addition, various methods have been researched and developed so as to obtain polymer particles with uniform particle size distribution in dispersion polymerization, but finding a manufacturing method that can improve the uniformity while eliminating the classification process, which is a post-treatment process, is possible. It is still difficult.

Amhoteric initiators are examples used in emulsion free polymerization. That is, there is an example in which spherical uniform polymer fine particles having a diameter of 1 μm or more are prepared by further adding an amphoteric initiator after the monomer is reacted in the polymerization step [J. Chem. Eng. Japan, 36, 1231, 2003; J. Colloid Interf. Sci., 281 249, 2005; Japanese Patent JP2003252912]. However, since the solubility of the amphoteric initiator in the organic solvent is not accurate, examples of particle generation using the amphoteric initiator are not yet known in other heterogeneous polymerization such as dispersion polymerization.

The present invention was developed as part of a study to design the optimal reaction conditions for producing vinyl polymer beads having better particle uniformity through dispersion polymerization. That is, the present inventors, in carrying out the dispersion polymerization method using a vinyl monomer, a polymerization initiator, a dispersion medium, and a steric stabilizer, by performing dispersion polymerization using an amphoteric initiator, known azo-based and peroxides which are currently generally used. The present invention has been completed by discovering that vinyl polymer particles having excellent particle uniformity in the range of an average particle diameter of 0.1 to 20 µm can be prepared than the method through the system initiator.

In the dispersion polymerization using the amphoteric initiator of the present invention, the decomposition rate is faster than that of the existing azo- or peroxide-based initiators at the same polymerization reaction temperature, so that the nucleation time is shortened, and thus the uniformity of the produced polymer particles is greatly improved.

In addition, in the dispersion polymerization method known so far, generally, the amount of the steric stabilizer should be 10 to 15 parts by weight based on 100 parts by weight of the monomer to obtain uniform and stable particles, but in the present invention, the steric stabilizer may be obtained by using an amphoteric initiator. Even when the amount of is used is 100 parts by weight of the monomer at least 1 part by weight it is possible to obtain a uniform and stable particles. Therefore, the amount of expensive steric stabilizer can be greatly reduced, and the uniformity of the prepared polymer particles is greatly improved, and thus, a classification process, which is a post-treatment process, can be omitted, and thus high economic effects can be expected.

Accordingly, an object of the present invention is to provide a spherical stable vinyl polymer bead having an average particle size of 0.1-20 占 퐉 in terms of particle size distribution more uniform than conventional dispersion polymerization methods, while using three-dimensional stabilizer by using an amphoteric initiator. To provide a method for producing a.

Other objects and advantages of the present invention will be described below and will be better understood by practice of the present invention.

In the present invention,

In the method of producing a vinyl polymer bead by dispersing a vinyl monomer, a polymerization initiator, a steric stabilizer in a dispersion medium,

An amphoteric polymerization initiator was used as the polymerization initiator, and the steric stabilizer was used at 1 to 5 parts by weight based on 100 parts by weight of the monomer, and the particle size distribution (CV) was 5% or less and the particle size was 0.1 to 20 μm. Provided is a method for producing vinyl polymer beads, which comprises obtaining polymer beads in the form of a ball.

In the present invention, the amphoteric polymerization initiator means an initiator having a functional group having a positive (+) like an amine group and a functional group having a negative (−) like a carboxyl group in the chemical structure of the initiator.

Referring to the manufacturing method of the vinyl-based polymer beads according to the present invention in more detail.

The choice of dispersion medium is important in carrying out dispersion polymerization. The dispersion medium should be capable of producing spherical vinyl polymer particles in a short time by dissolving all the components used in the polymerization to improve the reactivity, while not dissolving the vinyl polymer produced as a result of the polymerization. Therefore, in the present invention, the dispersion medium is selected from among the known solvents satisfying these requirements, and in consideration of the polymerization temperature of the present invention is in the range of 50 ~ 150 ℃, the boiling point of the dispersion medium is selected and used more than the polymerization temperature desirable. Preferably, as the dispersion medium of the present invention, an organic dispersion medium is used alone or water is mixed with the organic dispersion medium. As the organic dispersion medium, preferably, one or two or more kinds selected from alcohols, ether alcohols, and ketones may be mixed and used. For example, methanol; ethanol; Isopropyl alcohol; Butyl alcohol; Octyl alcohol; Benzyl alcohol; Cyclohexanol; Ethylene glycol; Glinerol; Diethylene glycol; Methyl cellosolve; Cellosolve; Butyl cellosolve; Isopropyl cellosolve; Ethylene glycol monomethyl ether; Ethylene glycol monoethyl ether; Diethylene glycol monomethyl ether; Diethylene glycol monoethyl ether; Acetone; Methyl ethyl ketone; Methyl isobutyl ketone and the like may be used alone or in combination of two or more.

In the present invention, the steric stabilizer is adsorbed on the surface of the particles when the vinyl-based polymer produced during the reaction precipitates into the particles to form a spherical shape of the particles and to prevent the collision between the particles to maintain the spherical shape. As the steric stabilizer, any of those which are dissolved in an aqueous solution or a non-aqueous solvent to stabilize dispersion can be used. In particular, as a stereostable agent that can be easily dissolved in the dispersion medium and maintain the spherical shape of the particles, for example, polyvinylpyrrolidone; Polyvinyl methyl ether; Polyethyleneamine; Polyacrylic acid; Polyvinyl alcohol; Polyvinylacetate; Polyvinylacetate copolymers; Ethyl cellulose; Hydroxypropylcellulose and the like can be used. The steric stabilizer is used in an amount of 1 to 5 parts by weight based on 100 parts by weight of the monomer. If the amount is less than 1 part by weight, it is difficult to obtain spherical particles, and when used in excess of 5 parts by weight, the surface of the polymer beads may be roughened.

In the present invention, the vinyl monomer may be used as long as it is possible to initiate radicals used in general dispersion polymerization, emulsion polymerization or suspension polymerization. As the vinyl monomer, for example, one or two or more selected from styrene compounds such as styrene, divinylbenzene, ethylvinylbenzene, alphamethylstyrene, fluorostyrene and vinylpyridine can be used. Moreover, cyan-type vinyl compounds, such as acrylonitrile and methacrylonitrile; Acrylate compounds such as butyl acrylate, 2-ethylhexylethyl acrylate, glycidyl acrylate, and N, N' -dimethylaminoethyl acrylate; Methacrylate-based compounds such as butyl methacrylate, 2-ethylhexylethyl methacrylate, methyl methacrylate, 2-hydroxyethyl methacrylate and glycidyl methacrylate; Diacrylate-based compounds such as polyethylene glycol diacrylate, 1,3-butylene glycol diacrylate, and 1,6-hexanediacrylate; And dimethacrylate compounds such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and 1,3-butylene glycol dimethacrylate. May be used alone or in combination of two or more thereof. The vinyl monomer is preferably used in an amount of 5 to 50 parts by weight, and more preferably 10 to 40 parts by weight, based on 100 parts by weight of the dispersion medium.

In the present invention, the amphoteric polymerization initiator may be used both in the chemical structure of the initiator, both functional groups having a positive (+) like an amine group and initiators having a functional group having a negative (−) like a carboxyl group. In the present invention, it is thought that the amphoteric initiator has a faster decomposition rate and a shorter nucleation time than the existing azo- or peroxide-based initiators at the same dispersion polymerization temperature, thereby greatly improving the uniformity of the resulting polymer particles. . As the amphoteric initiator, for example, 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate; 2,2'-azobis [N- (1-carboxyethyl) -2-methylpropionamidine] hydrate and 2,2'-azobis [N-carboxymethyl-2-methylpropionamidine] hydrate alone Or two or more kinds together. The amphoteric initiator is preferably used in an amount of 0.01 to 10 parts by weight, and more preferably 0.05 to 5 parts by weight, based on 100 parts by weight of the vinyl monomer. If the amount is less than 0.01 parts by weight, the rate of the polymerization reaction is significantly reduced, and when more than 5 parts by weight, the surface of the polymer particles becomes rough as in the case of the steric stabilizer.

The dispersion polymerization method itself used in the present invention is carried out at a polymerization temperature of 50 to 150 ° C. for 12 to 100 hours by applying a known method. In the present invention, the polymerization can be completed in a relatively short time by using the amphoteric initiator in the dispersion polymerization, and the polymerized vinyl polymer can be prepared into spherical particles having various sizes from 0.1 to 20 μm. The particle size distribution (CV) of shows a narrow range of 5% or less.

In addition, in the dispersion polymerization reaction of the present invention, well-known additives such as a polymerization regulator, a crosslinking agent, an anti-scale agent, a dye and a pigment, which are used for ordinary dispersion polymerization, may be added in a conventional manner as necessary.

Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the scope of the present invention is not limited by the following examples, and those of ordinary skill in the art to which the present invention pertains should be within the equivalent scope of the technical concept of the present invention and the claims to be described below. Of course, various modifications and variations are possible.

Example  1 to 6

Styrene was refrigerated after pretreatment to remove reaction inhibitors. 2 g of styrene, 10 g of methanol, 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate (VA-057) as an amphoteric initiator (2 parts by weight of monomer) in the reactor ), And the experiment was performed while changing the amount of the polyvinylpyrrolidone as a stereostable agent to 0.02 to 0.2g as shown in Table 1. At this time, after confirming that the mixture is a homogeneous phase in a transparent state, the nitrogen atmosphere was maintained and the temperature was raised to 60 ° C., followed by dispersion polymerization for 24 hours while stirring at 200 rpm to obtain polystyrene particles.

The size and particle size distribution of the polymer obtained after a predetermined reaction time were confirmed by a particle size analyzer (COULTER, LS230), and again by a scanning electron microscope. The results are shown in Table 1 and FIGS. 1 to 4.

Example  7 to 9

Methyl methacrylate was stored refrigerated after pretreatment to remove the reaction inhibitor. 0.04 g (monomer) of 2 g of methyl methacrylate, 10 g of methanol and 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate (VA-057) as an amphoteric initiator 2 parts by weight) and the experiment was performed while changing the amount of the polyvinylpyrrolidone as a stereo stabilizer to 0.04 ~ 0.1g as shown in Table 2. At this time, after confirming that the mixture was a homogeneous phase in a transparent state, the nitrogen atmosphere was maintained and the temperature was raised to 60 ° C., stirred at 200 rpm, and dispersed and polymerized for 24 hours to obtain polymethyl methacrylate particles.

The size and particle size distribution of the polymer obtained after a predetermined reaction time were confirmed by a particle size analyzer (COULTER, LS230), and again by a scanning electron microscope. The results are shown in Table 2 and FIGS. 5 to 7.

Example  10 to 13

2 g of styrene, 10 g of methanol, and 0.04 g of polyvinylpyrrolidone were placed in a reactor, and as shown in Table 3, an initiator 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate (VA The experiment was performed while changing -057) from 0.02 to 0.08 g. At this time, the nitrogen atmosphere was maintained and the temperature was raised to 60 ° C., followed by dispersion polymerization for 24 hours while stirring at 200 rpm.

The size and particle size distribution of the polymer obtained after a predetermined reaction time were confirmed by a particle size analyzer (COULTER, LS230), and again by a scanning electron microscope. The results are shown in Table 3 and FIGS. 8 to 10.

Example  14 to 16

2 g of styrene, 10 g of methanol, 0.04 g of polyvinylpyrrolidone and 0.04 g of 2,2′-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate (VA-057) as an amphoteric initiator Was put into the reactor and experimented for 24 hours at different temperatures as shown in Table 4. The reaction was carried out while maintaining the nitrogen atmosphere during the reaction and stirring at 200 rpm.

The size and particle size distribution of the polymer obtained after a predetermined reaction time were confirmed by a particle size analyzer (COULTER, LS230), and confirmed again through a scanning electron microscope, the results are shown in Table 4 below.

Example  17 to 18

2 g of styrene, 10 g of methanol, and 0.04 g of different steric stabilizers were added to the reactor as shown in Table 5, and 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate, an amphoteric initiator, was added to the reactor. (VA-057) 0.04 g was added to the experiment. During the reaction, a nitrogen atmosphere was maintained and the temperature was raised to 60 ° C., followed by dispersion polymerization for 24 hours while stirring at 200 rpm to obtain polystyrene particles.

The size and particle size distribution of the polymer obtained after a predetermined reaction time were confirmed by a particle size analyzer (COULTER, LS230), and again by a scanning electron microscope. The results are shown in Table 5 and FIG. 11.

Comparative example  1 to 2

2g of styrene, 10g of methanol, and 0.04g of polyvinylpyrrolidone were added to the reactor, and 0.04g of different initiators were added to the reactor as shown in Table 4, and the experiment was performed. During the reaction, a nitrogen atmosphere was maintained and the temperature was raised to 60 ° C., followed by dispersion polymerization for 24 hours while stirring at 200 rpm to obtain polystyrene particles.

The size and particle size distribution of the polymer obtained after a predetermined reaction time were confirmed by a particle size analyzer (COULTER, LS230), and again by a scanning electron microscope. The results are shown in Table 6 and FIGS. 12 and 13.

As can be seen through the above examples, in the dispersion polymerization method of the present invention, the particle size distribution is 5 while greatly reducing the amount of the steric stabilizer, which was conventionally used at 10 to 15 parts by weight, based on 100 parts by weight of monomer, to 1 to 5 parts by weight. Uniform and stable particles of up to% can be obtained. Therefore, according to the present invention, not only the amount of the steric stabilizer can be reduced, but also the uniformity of the prepared polymer particles is greatly improved, so that a classification process, which is a post-treatment process, can be omitted, and thus a high economic effect can be expected. The homogeneous spherical polymer particles of 0.1 to 20 μm prepared according to the present invention can be used as standard materials for measuring the instrument, measuring the size and efficiency of filter processing, packing materials for chromatography columns, supports in biochemistry, and biomedical fields. It can be used in a variety of high value-added fields such as microelectronics and information industries such as coatings, inks, polymerized toners for radiation, anisotropic conductive balls, and the like.

Claims (7)

In the method of producing a vinyl polymer bead by dispersing a vinyl monomer, a polymerization initiator, a steric stabilizer in a dispersion medium, An amphoteric polymerization initiator was used as the polymerization initiator, and the steric stabilizer was used at 1 to 5 parts by weight based on 100 parts by weight of the monomer, and the particle size distribution (CV) was 5% or less and the particle size was 0.1 to 20 μm. Method for producing a vinyl-based polymer beads, characterized in that to obtain a (bead) polymer beads. The method of claim 1, wherein the amphoteric polymerization initiator comprises 2,2′-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate (VA-057); 1 selected from 2,2′-azobis [N- (1-carboxyethyl) -2-methylpropionamidine] hydrate and 2,2′-azobis [N-carboxymethyl-2-methylpropionamidine] hydrate The production method characterized by the above-mentioned species or 2 or more types. The method of claim 2, wherein the amphoteric polymerization initiator is used in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the vinyl monomer. The vinyl monomer of claim 1, wherein the vinyl monomer is styrene; Divinylbenzene; Ethyl vinyl benzene; Alphamethylstyrene; Fluorostyrenes; Vinylpyridine; Vinyl chloride; Acrylonitrile; Methacrylonitrile; Butyl acrylate; 2-ethylhexylethyl acrylate; Glycidyl acrylate; N, N'-dimethylaminoethyl acrylate; Butyl methacrylate; 2-ethylhexylethyl methacrylate; Methyl methacrylate; 2-hydroxyethyl methacrylate; Glycidyl methacrylate; Polyethylene glycol diacrylate; 1,3-butylene glycol diacrylate; 1,6-hexanediacrylate; Ethylene glycol dimethacrylate; Diethylene glycol dimethacrylate; Triethylene glycol dimethacrylate; A production method characterized in that one or two or more selected from polyethylene glycol dimethacrylate and 1,3-butylene glycol dimethacrylate. According to any one of claims 1 to 3, wherein the steric stabilizer is polyvinylpyrrolidone; Polyvinyl methyl ether; Polyethyleneamine; Polyacrylic acid; Polyvinyl alcohol; Polyvinylacetate; Polyvinylacetate copolymers; 1 or 2 or more selected from ethyl cellulose and hydroxypropyl cellulose. The method of any one of claims 1 to 3, wherein the dispersion medium is an organic dispersion medium used alone or water is mixed with the organic dispersion medium. The method of claim 6, wherein the organic dispersion medium is methanol; ethanol; Isopropyl alcohol; Butyl alcohol; Octyl alcohol; Benzyl alcohol; Cyclohexanol; Ethylene glycol; Glinerol; Diethylene glycol; Methyl cellosolve; Cellosolve; Butyl cellosolve; Isopropyl cellosolve; Ethylene glycol monomethyl ether; Ethylene glycol monoethyl ether; Diethylene glycol monomethyl ether; Diethylene glycol monoethyl ether; Acetone; Methyl ethyl ketone; 1 or 2 or more selected from methyl isobutyl ketone.

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