JP2597254B2 - Suspension polymerization method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a function for controlling the fluidity and gloss properties of a gap-retaining agent, a slipping agent, a functional carrier, monodisperse particles having surface activity, standard particles, toner and paint. The present invention relates to a method for obtaining polymerization product particles suitable for use in the particle industry such as a filler, particularly particles having a controlled particle size and particle size distribution. The present invention relates to a suspension polymerization method in which formation of particles is prevented.

[0002]

2. Description of the Related Art In recent years, the importance of the particle industry utilizing the function of particles themselves has been increasing. However, gap-retaining agents, slipperiness-imparting agents, functional carriers, and surface active materials known as application fields have been increasing. Currently, emulsion polymerization is the main method for obtaining particles for applications such as dispersed particles, standard particles, toner, and functional fillers that control the fluidity and gloss properties of paints by emulsion polymerization. It is. For special applications, soap-free polymerization, dispersion polymerization, seed polymerization, swelling polymerization and the like are also applied. However, these polymerization methods have several disadvantages. For example, it is very difficult to remove non-negligible impurities such as emulsifiers, the particle size of the obtained particles is limited, the cost is extremely high, and the production method is complicated and is not suitable for mass production. There is. Also, in order to obtain particles having a narrow particle size distribution, an emulsion polymerization method is mainly used, but in the emulsion polymerization method, the particle size of the obtained particles is at most about 1 μm at most, and is larger than that. It is extremely difficult to obtain particles of

On the other hand, in the suspension polymerization method, although the product obtained is in the form of particles, only a product having a non-uniform particle size and a wide particle size distribution can be obtained. Improvements are desired because they have important relationships with performance such as strength, chemical resistance, hue, transparency and moldability. That is, in the suspension polymerization, the droplets dispersed by stirring have various diameters, and further, since the droplets repeatedly disperse and coalesce during dispersion, the particle size distribution of the obtained particles becomes extremely wide, and in particular, the particle size It is said that it is difficult to obtain monodisperse particles having a narrow distribution. Therefore, establishment of a suspension polymerization technique capable of easily obtaining homogeneous particles has been demanded as an important issue in the field of the particle industry.

The present inventors have previously found a new manufacturing method capable of easily solving the above problem (Japanese Patent Application No. 2-43980).
No.). That is, an apparatus capable of holding a dispersed phase (monomer composition phase) and a continuous phase in independent tanks and supplying the dispersed phase and the continuous phase simultaneously and continuously from the tanks through independent paths. Is supplied and passed once or more than once to a granulator capable of obtaining a suspension having droplets of a desired size, and then is introduced into a polymerization tank to complete the polymerization, thereby forming a polymer. The resulting suspension polymerization method. This method has a structure in which the liquid to be dispersed is directly supplied to a shearing force generating field for dispersion, and the suspension is designed to pass through the shearing force field when the liquid to be dispersed leaves the shearing force field. This is a legal method, and particles having a desired particle size with a narrow particle size distribution can be stably obtained by such a method. However, even in the suspension polymerization method as described above, it is inevitable that emulsified particles having a particle size of 1 micron or less are generated when a suspension is prepared, and the required yield of polymer particles is reduced. In addition, when a highly narrow particle size distribution is required, there is a problem that emulsified particles of 1 micron or less as described above are mixed.

[0005]

SUMMARY OF THE INVENTION According to the present invention, it is possible to easily obtain uniform polymer particles having a desired particle size having a narrow particle size distribution, particularly a small particle size, in a suspension polymerization method. An object of the present invention is to provide a suspension polymerization method in which the formation of submicron emulsified particles is prevented.

[0006]

According to the present invention, a dispersion phase and a continuous phase composed of at least a polymerizable monomer are held in independent tanks, respectively, and each is separated at a controlled ratio through an independent path. The suspension is supplied to the granulator two or more times to obtain a suspension having polymerizable droplets of a desired size, and then the suspension is introduced into a polymerization vessel to complete the polymerization, thereby obtaining a polymer. Is a suspension polymerization method characterized in that a metal complex compound of a monoazo dye represented by the following general formula is contained in a continuous phase.

Embedded image In the formula, A and A 'are unsubstituted or substituted phenylene groups, and B and B' are unsubstituted or substituted naphthyl groups. Here, the substituents of the phenylene group and the naphthyl group are not particularly limited, and examples thereof include a halogen, a carboxy group, a sulfonic group, a nitro group, an amino group, an amide group, and the like. M represents a metal, for example, Cr, Co, Fe, V, and the like, and R ₁ , R ₂ , R ₃ , and R ₄ represent O and NH .

First, an example of an apparatus for performing the suspension polymerization method of the present invention will be described with reference to the drawings. As shown in FIG. 1, a continuous phase tank 1 containing a continuous phase and a dispersed phase tank 2 provided with a condenser 6 containing a dispersed phase are supplied to a granulator 5 via a constant-quantity pump 4, 4 at a fixed ratio. At the same time, a shearing force is applied to discharge the droplets as a suspension in a certain size range, and the suspension is guided to a polymerization tank 3 equipped with a condenser 6. The required heating is carried out by the heating jacket 7 provided in the above, and the polymerization reaction is completed, and a product having a small particle size and a uniform particle size distribution can be obtained. An example of the granulator 5 used here is as shown in FIG. 2, in which a lower portion constitutes an inflow double tube, an upper portion constitutes a stirring and discharging portion, and a lower portion has a double tube having an inner tube inlet 19 at the center. The pipe 16 has a double pipe outer pipe 17 having an outer pipe inlet 18 around the pipe 16 and is connected to the upper part via an opening diameter adjusting flange 20. In the center of the upper part, the turbine rotation shaft 11,
A bearing 14 and a turbine 15 are provided between the stirring seal 12 and the dispersion liquid discharge port 13 and the lower part. In the present invention, in the above-mentioned polymerization method, particularly by dispersing and using a metal complex compound of a monoazo dye having the structure as described above in the continuous phase, the particle size distribution is narrower than in the past, and the desired particle size is obtained. Polymer particles having a small diameter can be obtained,
In addition, uniform polymer particles containing almost no fine particles of 1 micron or less can be obtained with high yield. In addition, the addition amount of the metal complex compound of the monoazo dye in the continuous phase in the present invention is 0.01 to 10% by weight.
Is appropriate. Here, if it is less than 0.01%, it is difficult to obtain the above-mentioned effects in the present invention, and if it exceeds 10%, polymerization may be inhibited, which is not preferable.

[0008] The disperse phase in the present invention contains at least a polymerizable monomer, and if necessary, a polymerization initiator,
Various additives can be used depending on the purpose of the coloring pigment and other polymer particles. Examples of the polymerizable monomer used in the present invention include the following compounds. Styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene, 2,4-dimethyl styrene,
Styrene such as pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene and derivatives thereof; ethylene, Ethylene unsaturated monoolefins such as propylene, butylene and isobutylene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride; organic acid vinyl esters such as vinyl acetate, vinyl propionate and vinyl benzoate Methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate,
Methacrylic acid such as stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate and derivatives thereof; acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate , N-octyl acrylate, dodecyl acrylate,
Acrylic acid and its derivatives such as 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate and phenyl acrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether; vinyl methyl ketone and vinyl hexyl ketone , Vinyl isopropenyl ketones and the like; N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone; vinyl naphthallines;

The polymerization initiator that can be used in the present invention is preferably soluble in a polymerizable monomer. Examples of such a polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis- (2,4-dimethylvaleronitrile) and 2,2'-azobis-4-methoxy-.
2,4-dimethylvaleronitrile, other azo-based or diazo-based polymerization initiators; benzoyl peroxide, methyl ethyl ketone peroxide, isopropyl peroxycarbonate, and other peroxide-based polymerization initiators. Further, as the coloring pigment, carbon black, various color pigments, and the like can be appropriately used. By adding and polymerizing such a color pigment, it can be easily applied to, for example, the production of an electrophotographic toner.

Next, the continuous phase in the present invention is formed by a continuous layer component composed of an aqueous medium, and contains, in addition to the metal complex compound of the above-mentioned monoazo dye, additives such as a suspension stabilizer and auxiliaries as appropriate. Have been. As a suspension stabilizer,
A suspension stabilizer generally used in suspension polymerization can be used, and a water-soluble polymer having a hydrophilic group and a hydrophobic group in its molecule is often used. The suspension stabilizer has a polar group such as a hydroxyl group, a carboxyl group and a salt thereof, a sulfone group and a salt thereof as a hydrophilic group, and is composed of a nonpolar group such as an aliphatic group and an aromatic group as a hydrophobic group. A compound having the ability to prevent and stabilize the coalescence of the monomer composition particles formed by the granulation step. Examples of such a suspension stabilizer include polyvinyl alcohol, casein, gelatin, cellulose derivatives such as methylcellulose, methylhydroxypropylcellulose, and ethylcellulose, starch and its derivatives, poly (meth) acrylic acid, and salts thereof. ing. In addition, inorganic powders such as calcium phosphate and finely divided silica are often used. These suspension stabilizers serve to coat the droplet surface during polymerization and prevent coalescence and agglomeration of the droplets. Further, a surfactant such as sodium dodecylsulfonate, sodium dodecylbenzenesulfonate and the like can be added as an auxiliary of the suspension stabilizer. In addition, neutral salts such as sodium chloride and sodium sulfate may be added to the continuous phase (aqueous phase) for the purpose of preventing emulsification. For the purpose of preventing coalescence of the monomer composition particles formed by the granulation step,
A thickener such as glycerin or ethylene glycol may be added.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments. Example 1 As a continuous phase, a 10% aqueous dispersion of tribasic calcium phosphate was 50% based on water, and sodium sulfate was 3% based on water.
0.01% of sodium dodecylbenzenesulfonate
An aqueous solution was prepared by dispersing 0.1% of a metal complex compound of a monoazo dye represented by the following structural formula (1) (a mixture of n = 1 and 2) in this dispersion. I was in the tank.

Embedded image Also, a solution in which 15 g of 2,2'-azobisisobutyronitrile is dissolved in a mixed solution of 4000 g of styrene and 1000 g of butyl acrylate as a disperse phase is prepared, and carbon black (MA-100 manufactured by Mitsubishi Kasei Co., Ltd.) ) 4
00g was dispersed. This solution was placed in the dispersion phase tank shown in FIG. Next, the dispersed phase was 100 ml / min and the continuous phase was 40 ml / min.
It was fed to the granulator at ml / min for 10 minutes. Fig. 2
Was operated at 10000 rpm by using a granulator shown in FIG. The suspension that has passed through the granulator is subjected to 300 r with a turbine type stirring blade.
While stirring at pm, the mixture was guided into the polymerization tank shown in FIG. 1 and reacted for 8 hours. Thereafter, the reaction solution was separated by filtration to obtain polymer particles,
Further, the particles were sufficiently washed with 3% nitric acid and water, and dried under reduced pressure at 40 ° C. for 12 hours to obtain polymer particles by the suspension polymerization method of the present invention.

Comparative Example 1 Comparative polymer particles were obtained in the same manner as in Example 1 except that the metal complex compound of the monoazo dye was not used. Example 2 In Example 1, the compound of the following structural formula (2) was used as the metal complex compound of the monoazo dye used in the continuous phase, and a red dye (OI) was used instead of the carbon black used in the dispersed phase.
L PINK312, manufactured by Orient Chemical Co., Ltd.), and polymer particles were obtained by the suspension polymerization method of the present invention in exactly the same manner as in Example 1.

Embedded image

Comparative Example 2 Comparative polymer particles were obtained in the same manner as in Example 2 except that the metal complex compound of the monoazo dye was not used. Examples 1 and 2 and Comparative Examples 1 and 2 above
The results of measuring the particle size distribution of the polymer particles obtained in the above with a Microtrac particle size analyzer (manufactured by Nikkiso Co., Ltd.) are as shown in FIGS. 3 and 4, and the polymer particles obtained by the suspension polymerization method of the present invention It was confirmed that no fine particles of 1 micron or less were generated and the particle size distribution was narrow.

[0014]

The suspension polymerization method of the present invention has a very narrow particle size distribution that does not contain fine particles because it can prevent the formation of emulsified particles of 1 micron or less that are formed in suspension. It has an excellent effect that polymer particles can be obtained. In addition, small particles on the order of microns can be obtained without containing fine particles of 1 micron or less, so that they are expected to be used as highly functional particles in various fields including electrophotographic toners.

[0015]

[Brief description of the drawings]

FIG. 1 is an example of a polymerization apparatus used in the suspension polymerization method of the present invention.

FIG. 2 is an example of a granulator used in the suspension polymerization method of the present invention.

FIG. 3 is a graph showing the particle size distribution of polymer particles obtained in Example 1 and Comparative Example 1 of the present invention.

FIG. 4 is a graph showing the particle size distribution of polymer particles obtained in Example 2 and Comparative Example 2 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Continuous phase tank 2 Dispersion phase tank 3 Polymerization tank 4 Metering pump 5 Granulator 6 Condenser 7 Heating jacket 11 Turbine rotating shaft 12 Stirring seal 13 Dispersion liquid discharge port 14 Bearing 15 Turbine 16 Double pipe inner pipe 17 Double pipe Outer pipe 18 Outer pipe inlet 19 Inner pipe inlet 20 Flange for opening diameter adjustment

Claims (1)

(57) [Claims] 1. A disperse phase and a continuous phase comprising at least a polymerizable monomer are held in independent tanks, respectively, and are passed through independent paths at a controlled ratio of once to two times.
The suspension is supplied to a granulator at least twice to obtain a suspension having polymerizable droplets of a desired size, and then the suspension is introduced into a polymerization tank to complete the polymerization to obtain a polymer. In the turbid polymerization method,
A suspension polymerization method comprising a metal complex compound of a monoazo dye represented by the following general formula in a continuous phase. Embedded image (Wherein A and A 'are unsubstituted or substituted phenylene groups, B and B' are unsubstituted or substituted naphthyl groups. M represents a metal, R ₁ , R
₂ , R ₃ and R ₄ represent O and NH . )