JPH0885706A - Suspension polymerization method - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide a novel suspension polymerization method capable of obtaining fine polymer particles containing a natural wax. [Structure] The dispersed phase and the continuous phase are held in independent tanks, respectively, and they are fed to a granulator at a controlled ratio once or twice or more through independent paths to carry out polymerization of a desired size. In a suspension polymerization method in which a suspension having hydrophilic droplets is obtained, and then the suspension is introduced into a polymerization tank to complete polymerization to obtain fine polymer particles, the dispersed phase is a polymerizable monomer. A suspension polymerization method containing a mixture with a natural wax.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for producing polymer fine particles containing a natural wax by a suspension polymerization method.

[0002]

2. Description of the Related Art The suspension polymerization method is a method in which a polymerizable monomer is made into a suspension having polymerizable droplets by mechanical shearing force using a dispersion stabilizer in an aqueous medium, and polymerization is carried out in this suspension. Is a method of doing. Therefore, during the reaction, it is easy to keep the viscosity of the reaction liquid low, and since the reaction is performed in an aqueous medium, it is easy to remove the heat of polymerization.
Therefore, the suspension polymerization method is widely used on an industrial scale as a method for producing a large amount of polymer fine particles at low cost. By the way, there has been an attempt to reduce the melting point of the polymer particles themselves or improve the lubricity by incorporating a natural wax into the polymer particles. The polymer particles containing the natural wax are used in the fields of toner and cosmetics used in electrophotography, and functional fillers that control the fluidity and luster characteristics of paints. Then, it has been tried to obtain fine polymer particles containing a natural wax by using the suspension polymerization method having the above characteristics. However, in the conventional suspension polymerization method, since polar functional groups such as a hydroxyl group, a carboxyl group and an amino group are present in the natural wax,
During the suspension operation, the polymerizable monomer and the natural wax are separated while the droplets repeatedly break up and coalesce, so that the polymer fine particles containing the natural wax cannot be obtained. Was there.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel suspension polymerization method capable of obtaining fine polymer particles containing a natural wax.

[0004]

DISCLOSURE OF THE INVENTION According to the present invention, the dispersed phase and the continuous phase are held in independent tanks, respectively, and both are passed through independent paths, at a controlled ratio, once or twice or more. To obtain a suspension having polymerizable droplets of a desired size, and then introducing the suspension into a polymerization tank to complete the polymerization to obtain polymer fine particles in a suspension polymerization method. ,
The suspension polymerization method is characterized in that the dispersed phase contains a mixture of a polymerizable monomer and a natural wax.

First, an example of an apparatus for carrying out the suspension polymerization method of the present invention will be described with reference to the drawings. As shown in FIG. 1, the apparatus for carrying out the present invention comprises a continuous phase tank 1 containing a continuous phase and a dispersion phase tank 2 equipped with a condenser 6 containing a dispersion phase, which are provided as metering pumps 4 and 4, respectively. It is designed to be simultaneously introduced into the granulator 5 at a constant ratio via a separator, where a shearing force is applied to discharge a certain size of the droplets as a suspension, and a polymerization tank equipped with a condenser 6 is provided. 3 and a heating jacket 7 provided around the polymerization tank 3
Therefore, the required heating is performed to complete the polymerization reaction. As a result, polymer fine particles having a small particle size and a uniform particle size distribution can be obtained. The granulator 5 may be provided so as to supply the dispersed phase and the continuous phase once or twice or more, or a plurality of the granulators 5 may be provided to distribute the dispersed phase and the continuous phase to the plural granulators. It may be supplied. The present invention is characterized in that the dispersed phase contains a mixture of a polymerizable monomer and a natural wax. After the natural wax is well dispersed and mixed in the polymerizable monomer, it is passed through a granulator to obtain droplets, so there is no process of droplet division or coalescence, so the polymerizable monomer and natural Polymer fine particles are obtained without being separated from the wax. Further, in the present invention, when the polymerizable monomer and the natural wax are mixed, it is preferable that the heating temperature is 50 ° C. or higher while mixing, and the heating temperature is 50 ° C. or higher. The polymerizable monomer and the natural wax are well dispersed. When the heating temperature is lower than 50 ° C., the natural wax cannot be well dispersed in the polymerizable monomer, and the polymerizable monomer and the natural wax are easily separated during the polymerization.

As the polymerizable monomer constituting the present invention,
Styrene, o-methylstyrene, m-methylstyrene,
p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert. -Styrene and its derivatives such as butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene and pn-decyl styrene; ethylene unsaturated such as ethylene, propylene, butylene and isobutylene Mono-olefins; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride, etc .; organic acid vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate; methacrylic acid, methyl methacrylate, methacryl Ethyl acid, propyl methacrylate, n-butyl methacrylate Methacrylic acid n- octyl, dodecyl methacrylate, 2-ethylhexyl methacrylate,
Methacrylic acid and its derivatives such as stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate; 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, phenyl acrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether; vinyl methyl ketone, vinyl hexyl ketone , Vinyl isopropenyl ketone, and other vinyl ketones; N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone, and other N-vinyl compounds; vinyl naphthalines; acrylonitrile, methacrylonitrile, acrylamide, and the like. Can be mentioned. Especially to improve the dispersibility of natural wax,
It is preferred to add acrylic acid or its derivatives to the dispersed phase.

Examples of the natural wax constituting the present invention include wood wax, beeswax, candelilla wax, rice wax, lanolin, carnauba wax and the like. The content of the natural wax is preferably 0.5 to 50 parts by weight based on 100 parts by weight of the polymerizable monomer because the natural wax is well dispersed in the polymerizable monomer. Further, the melting point of the natural wax is preferably 95 ° C. or lower, and when the melting point is higher than 95 ° C., the natural wax becomes difficult to disperse in the polymerizable monomer, which is not preferable. A polymerization initiator may be added to the dispersed phase constituting the present invention. The polymerization initiator is preferably soluble in a polymerizable monomer, and examples of such a polymerization initiator include N, N'-azobisisobutyronitrile and 2,2'-azobisiso Butyronitrile,
2,2'-azobis- (2,4-dimethylvaleronitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, other azo or diazo polymerization initiators; benzoyl peroxide , Methyl ethyl ketone peroxide, isopropyl peroxy carbonate, other peroxide-based polymerization initiators, and the like. Further, a colorant such as a dye or a pigment may be dissolved or dispersed in the dispersed phase, and then the polymerizable monomer may be polymerized to obtain colorable polymer fine particles. As dyes and pigments,
Examples thereof include carbon black, iron black, rose bengal, benzidine yellow, quinacridone, rhodamine B, phthalocyanine and mixtures thereof.

In the present invention, the dispersed phase and the continuous phase are held in independent tanks, and they are supplied to the granulator at a controlled ratio once or twice or more through independent paths, respectively. A suspension having polymerizable droplets of the size is obtained, and the suspension is then introduced into a polymerization tank and subjected to suspension polymerization. It is carried out at a temperature of ℃ or higher, and the temperature is set in consideration of the decomposition temperature of the polymerization initiator. If the set temperature is too high, the polymerization initiator will be rapidly decomposed and the molecular weight will be affected, which is not preferable. The supply amount ratio of the dispersed phase and the continuous phase to the granulator is 1:
1 to 1:10 is preferable, and more preferably 1: 2 to 1.
It is 1:10. When the ratio of the continuous phase to the dispersed phase 1 is less than 1, it is difficult to obtain polymer fine particles because a suspension cannot be obtained. When the ratio of the continuous phase to the dispersed phase 1 is more than 10, the polymerizability is high. Since the amount of the monomer is small, the productivity per unit time may be poor. The continuous phase is mainly composed of water, but an organic solvent which does not dissolve the fine polymer particles other than water can be applied. In addition, it is preferable to add a dispersion stabilizer to the continuous phase in order to improve the dispersion of the dispersed phase. Examples of the dispersion stabilizer include organic compounds such as carboxymethyl cellulose and polyvinyl alcohol, and water resistant compounds such as calcium sulfate and tricalcium phosphate. Soluble inorganic fine particles can be used. The amount of the dispersion stabilizer added is preferably 0.2 to 20% by weight, more preferably 0.5 to 20% by weight, based on the continuous phase.
~ 5% by weight. 0.2% by weight of dispersion stabilizer
When the amount is less, it is difficult to obtain sufficient dispersion stability of the dispersed phase, and when the amount is more than 20% by weight, it becomes difficult to remove the dispersion stabilizer from the polymer fine particles obtained from the polymerization reaction. It is also possible to add a surfactant such as sodium dodecyl sulfonate or sodium dodecylbenzene sulfonate as an auxiliary agent of the dispersion stabilizer. In addition, neutral salts such as sodium chloride, sodium sulfate and sodium dodecyl sulfate may be added to the continuous phase for the purpose of preventing emulsification. Further, a thickener such as glycerin or ethylene glycol may be added for the purpose of preventing coalescence of the polymer fine particles obtained by the polymerization reaction.

[0009]

EXAMPLES Next, the present invention will be specifically described with reference to Examples and Comparative Examples. (A) Preparation of dispersed phase (1) To 2000 g of styrene, 200 g of rice wax (No1 Wax Co., No. 1, melting point 83 ° C.) was added, and 65 ° C.
While heating at 0 ° C., the mixture was stirred and dispersed with a disperser (Homomixer M type manufactured by Tokushu Kika Kogyo Co., Ltd.) at 10,000 rpm for 10 minutes, and then 25 g of N, N′-azobisisobutyronitrile was added and dissolved to obtain a dispersion. The liquid was used as the dispersed phase (a). (2) In the preparation of the dispersed phase of (1), carnauba wax (No1 manufactured by Noda Wax Co., Ltd.) was used instead of rice wax.
A dispersion prepared by the same method except that 400 g of a melting point of 85 ° C.) was used as a dispersion phase (b). (3) In the preparation of the dispersed phase of (1), instead of rice wax, candelilla wax (No. 1 manufactured by Noda Wax Co., Ltd.)
A dispersion prepared by the same method except that 500 g of a melting point of 86 ° C.) was used as a dispersion phase (c).

(4) In the preparation of the dispersed phase of (1), styrene was mixed with methyl methacrylate (manufactured by Wako Pure Chemical Industries, Ltd.) 50
A dispersion prepared by the same method except that g was added was used as a dispersion phase (d). (5) A dispersion prepared by the same method as in (1) except that 10 g of methacrylic acid (manufactured by Wako Pure Chemical Industries, Ltd.) was added to styrene was used as a dispersion phase (e). (6) To 2000 g of styrene, 200 g of rice wax (No1 wax No. 1 melting point 83 ° C.) was added and 65 ° C.
While being heated to 1, the mixture was stirred and dispersed by a disperser (Homomixer M type manufactured by Tokushu Kika Kogyo Co., Ltd.) at 10,000 rpm for 10 minutes, and then carbon black (manufactured by Cabot Co., trade name: AC).
ARB304) was added in an amount of 200 g, and the mixture was stirred at 5000 rpm for 10 minutes with a disperser (Homomixer M type manufactured by Tokushu Kika Kogyo Co., Ltd.) to obtain a carbon black dispersion. To this dispersion, 50 g of N, N'-azobisisobutyronitrile was added and dissolved. The obtained dispersion was used as a dispersion phase (f). (7) 200g of rice wax (No. 1 No. Wax Co., melting point 83 ° C) was added to 2000g of styrene at 65 ° C.
After stirring and dispersing with a disperser (manufactured by Tokushu Kika Kogyo Co., Ltd., Homomixer M type) at 10,000 rpm for 10 minutes, 5 g of Rose Bengal (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the mixture was stirred at 150 rpm with a turbine stirring blade at 10 rpm. After stirring for a minute, a rose bengal solution was obtained. To this solution, 25 g of N, N'-azobisisobutyronitrile was added and dissolved. The resulting solution was used as the dispersed phase (g). (8) A dispersion liquid was prepared in the same manner as in the preparation of the dispersed phase of (1) except that the heating temperature for mixing styrene and rice wax was 25 ° C. The dispersion was opaque. The obtained dispersion liquid was used as a dispersion phase (h).

(B) Preparation of continuous phase To 1000 g of water, 1000 g of tricalcium phosphate (trade name: TCP-10 manufactured by Taihei Chemical Industry Co., Ltd.) was added and stirred well. Furthermore, 0.8 g of sodium dodecyl sulfate is added,
The dissolved liquid is used as the continuous phase. <Example 1> 2000 g of the above continuous phase was added to the continuous phase tank 1 of FIG.
Further, 2000 g of the above dispersed phase (a) was further added to the dispersed phase tank 2 in FIG. Both phases were fed to the granulator 5 by the metering pump 4 at a continuous phase of 500 ml / min and a dispersed phase of 50 ml / min. Adjust the linear velocity of the rotating part of the granulator 5 to 15 m / s,
A dispersion was obtained. Then, the obtained dispersion liquid was introduced into the polymerization tank 3 provided with a low shear stirring device. After all the phases were dispersed, the dispersion was heated in the polymerization tank 3 at 15 rpm while being stirred at 80 ° C. for 7 hours, further heated to 90 ° C., and then heated for 1 hour. Then, after cooling to room temperature, 10 Kg of water and 300 g of concentrated nitric acid were added to the contents and stirred for 30 minutes. The content was transferred to a centrifugal dehydrator, most of the water was removed by centrifugal dehydration, and then dried by a vacuum dryer until the water content was 0.3% or less, to obtain polymer fine particles. When observing the shape of the polymer fine particles with an optical microscope, all have a spherical shape, and the natural wax is contained in the polymer fine particles and the natural wax is not separated. When measured with a Coulter counter (aperture 100 μm), the volume average particle diameter was 5.7 μm. <Example 2> Polymer fine particles were obtained in the same manner as in Example 1 except that the dispersed phase (b) was used in place of the dispersed phase (a). When observing the shape of the polymer fine particles with an optical microscope, all have a spherical shape, and the natural wax is contained in the polymer fine particles and the natural wax is not separated. The volume average particle diameter measured by a Coulter counter (aperture 100 μm) was 7.9 μm.

<Example 3> Polymer fine particles were obtained in the same manner as in Example 1, except that the dispersed phase (c) was used in place of the dispersed phase (a). When observing the shape of the polymer fine particles with an optical microscope, all have a spherical shape, and the natural wax is contained in the polymer fine particles and the natural wax is not separated. The volume average particle diameter measured by a Coulter counter (aperture 100 μm) was 6.4 μm. <Example 4> Polymer fine particles were obtained in the same manner as in Example 1 except that the dispersed phase (d) was used instead of the dispersed phase (a). When observing the shape of the polymer fine particles with an optical microscope, all have a spherical shape, and the natural wax is contained in the polymer fine particles and the natural wax is not separated. When measured with a Coulter counter (aperture 100 μm), the volume average particle diameter was 5.6 μm. <Example 5> Polymer fine particles were obtained in the same manner as in Example 1 except that the dispersed phase (e) was used instead of the dispersed phase (a). When observing the shape of the polymer fine particles with an optical microscope, all have a spherical shape, and the natural wax is contained in the polymer fine particles and the natural wax is not separated. When measured with a Coulter counter (aperture 100 μm), the volume average particle diameter was 6.1 μm. <Example 6> Polymer fine particles were obtained in the same manner as in Example 1 except that the dispersed phase (f) was used in place of the dispersed phase (a). When observing the shape of the polymer fine particles with an optical microscope, all have a spherical shape, and the natural wax is contained in the polymer fine particles and the natural wax is not separated. When measured with a Coulter counter (aperture 100 μm), the volume average particle diameter was 9.3 μm. <Example 7> Polymer fine particles were obtained in the same manner as in Example 1 except that the dispersed phase (g) was used instead of the dispersed phase (a). When observing the shape of the polymer fine particles with an optical microscope, all have a spherical shape, and the natural wax is contained in the polymer fine particles and the natural wax is not separated. The volume average particle diameter measured by a Coulter counter (aperture 100 μm) was 4.9 μm. <Example 8> In Example 1, the amount of the dispersed phase supplied to the granulator 5 was 500 ml per minute, and the amount of the continuous phase supplied was 15 ml.
Polymer fine particles were obtained by the same method except that the amount was adjusted to 0 ml. When observing the shape of the polymer fine particles with an optical microscope, all have a spherical shape, and the natural wax is contained in the polymer fine particles and the natural wax is not separated. When measured with a Coulter counter (aperture 100 μm), the volume average particle diameter was 8.3 μm. <Example 9> Polymer fine particles were obtained in the same manner as in Example 1 except that the dispersed phase (h) was used instead of the dispersed phase (a). When the shape of the polymer fine particles was observed with an optical microscope, they all had a spherical shape, and their particle diameters were determined by a Coulter counter (aperture 100 μm).
The volume average particle diameter measured by m) was 12.3 μm. However, when the reaction liquid after the polymerization reaction was observed, it was found that the liquid crystal of Example 1
Scale was attached as compared with 8. When the composition of the scale was analyzed, 80% (by weight) or more of the wax component was detected. <Comparative Example 1> To a 1-liter separable flask equipped with a three-necked cover, 500 g of water and 5000 g of tricalcium phosphate (trade name: TCP-10, manufactured by Taihei Chemical Industry Co., Ltd.) were added and well stirred, and sodium dodecyl sulfate of 0. 4 g was added and dissolved, and the mixture was heated to 65 ° C. while stirring at 300 rpm using a turbine type stirring blade having a diameter of 5 cm. next,
In this flask, 200 g of styrene and 20 g of rice wax (No1 wax No. 1 melting point 83 ° C.) were added and heated to 65 ° C. while being dispersed (made by Tokushu Kika Kogyo Co., Ltd.).
(Homomixer M type) was stirred and dispersed at 10,000 rpm for 10 minutes, and 2.5 g of N, N'-azobisisobutyronitrile was added and dissolved in the solution.
It was heated for an hour and further heated at 90 ° C. for 1 hour to polymerize. When the contents of the flask after the reaction were examined, a large amount of scale floated on the liquid surface, and a large amount of aggregated particles were present in the liquid. When the composition of this scale was examined, most of it was rice wax. That is, during the reaction, the rice wax was separated from the polymerizable fine particles, and the polymerizable particles containing the rice wax could not be obtained at all.

[0013]

The suspension polymerization method of the present invention has an excellent effect that polymer fine particles containing a natural wax can be obtained.

[Brief description of drawings]

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

[Explanation of symbols]

 1 Continuous phase tank 2 Dispersion phase tank 3 Polymerization tank 4 Metering pump 5 Granulator 6 Condenser 7 Heating jacket

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuhiro Okugawa 3-1, Soba-cho, Shizuoka-shi, Shizuoka Prefecture Tomoegawa Paper Mill Technical Research Institute

Claims (8)

[Claims] 1. A dispersion phase and a continuous phase are held in independent tanks, respectively, and both are supplied to a granulator at a controlled ratio once or twice or more through independent paths to obtain a desired size. In the suspension polymerization method of obtaining a suspension having polymerizable droplets, and then introducing the suspension into a polymerization tank to complete the polymerization to obtain fine polymer particles, the dispersed phase is a polymerizable monomer. A suspension polymerization method comprising a mixture of a body and a natural wax. 2. A polymerizable monomer and a natural wax are mixed in an amount of 50.
The suspension polymerization method according to claim 1, wherein the mixture is mixed while heating at a temperature of not less than 0 ° C. 3. The suspension polymerization method according to claim 1, wherein 0.5 to 50 parts by weight of a natural wax is mixed with 100 parts by weight of the polymerizable monomer. 4. The suspension polymerization method according to claim 1, wherein acrylic acid or a derivative thereof is dissolved in the dispersed phase and then polymerized. 5. The suspension polymerization method according to claim 1, wherein the melting point of the natural wax is 95 ° C. or lower. 6. The suspension polymerization method according to claim 1, wherein the dye is dissolved in the dispersed phase and then the polymerization is performed. 7. The suspension polymerization method according to claim 1, wherein the pigment is dispersed in the dispersed phase, and then the polymerization is carried out. 8. The suspension polymerization method according to claim 1, wherein the supply ratio of the dispersed phase and the continuous phase supplied to the granulator is 1: 1 to 1:10.