JP3334137B2 - Method for producing toner particles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing toner particles,
More particularly to a method of manufacturing a toner particle probe used for a copying machine.

[0002]

2. Description of the Related Art As a method for producing fine resin particles having a relatively uniform particle size, a method utilizing a suspension polymerization method or an emulsion polymerization method is known, but usable monomer species are limited. The types of resin particles obtained are limited. As a method for obtaining various resin particles without having such a problem, there is a method for obtaining a resin solution from an emulsion formed by dispersing or emulsifying the resin solution in a solution incompatible with the solution.

However, even if a resin solution is simply dispersed and emulsified in a dispersing solvent or the like to form an emulsion, the resin particles obtained therefrom tend to have a broad particle size distribution and are liable to generate fine powder. is there. Techniques for solving such problems include, for example, Japanese Patent Publication No. Sho 61-28688.
However, setting of various conditions is strictly required, and resin particles having a uniform particle size cannot be easily obtained.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and relates to a method for producing toner particles from an emulsion. It is an object of the present invention to provide a method for obtaining toner particles having a uniform diameter.

[0005]

That is, according to the present invention, an aqueous solution II is added to a resin solution I containing a resin and a colorant, using a hydrophobic solvent as a medium, to cause phase inversion.
A method for producing toner particles by removing the solvent of solution I and solution II after forming a W-type emulsion, wherein the resin solution I is 3 to 30 cp at 23 ° C.
And 1 to 20 cp higher than the viscosity of aqueous solution II.
The aqueous solution II has a high viscosity ,
The present invention relates to a method for producing toner particles having a viscosity of ２０20 cp .

In the present invention, first, a solution in which a resin or the like having a specific viscosity is dissolved (hereinafter referred to as "solution I") and an aqueous solution which may contain an emulsifying aid (hereinafter referred to as "solution II") are prepared. I do.

[0007] The resin which can be granulated by the method of the present invention is not particularly limited, and may be any resin as long as it is insoluble in aqueous solution II. Accordingly, as long as there is a solvent having the following properties capable of dissolving the resin, any resin known as a resin for constituting a toner can be used. For example, styrene resins known as preparative toner-constituting resin, polyester resin,
A styrene-acrylic resin or the like may be used.

The solvent used for the solution I is selected to dissolve the target resin and to be substantially insoluble in the aqueous solution II. Furthermore, when the solvent is removed by heating in the final step of the present invention, it is preferable to use a solvent which is lower than the melting point of the resin used and lower than the boiling point of the aqueous solvent of the solution II. Even if the boiling point is slightly higher than the aqueous solvent of II, it can be used because it azeotropes. Solution I
Specific examples of the solvent that can be used for the hydrocarbon include, for example, hexane, cyclohexane, benzene, tetralin, and the like.
Halogenated hydrocarbons such as chloroform, carbon tetrachloride, methylene chloride and the like. These mixed solvents may be used.

Solution I is obtained by dissolving the target resin in the above-mentioned solvent in an amount of 5 to 50% by weight, preferably 10 to 40% by weight, and has a viscosity at 23 ° C. (hereinafter referred to as “cp”) of 3 to 3 %.
0 cp, preferably 5 to 20 cp. The viscosity of this solution I is 1 to 20 times higher than that of solution II described below.
cp, preferably 2-15 cp. When a solution adjusted to a viscosity outside the above range is used, fine particles are likely to be generated in toner particles which are final products.

[0010] To a solution I may be added to seed s of additives For example, wear colorant may be a predetermined amount added charge control agent and other desired additives.

Next, the preparation of the solution II will be described.
Solution II is a solvent that is not compatible with solution I, typically water or an aqueous solution of an emulsifying aid. A hydrophilic solvent such as methanol, ethanol, isopropanol, acetone and the like may be used in combination. In addition, a charge control agent,
When a colorant, an antioxidant or the like is to be adhered or coated, those components may be dissolved and used. Examples of the emulsifying aid include a surfactant and a dispersion stabilizer. Surfactants contribute to the stabilization of the emulsion after phase inversion. As the surfactant, an ionic surfactant is particularly preferred.

Examples of the ionic surfactant include an anionic surfactant such as a carboxylate, a sulfate, a sulfonate and a phosphate, or a primary amine salt.
Secondary amine salts, tertiary amine salts, and quaternary ammonium salt cationic surfactants can be exemplified. The addition amount is 0.5 to 3% by weight of solution II, preferably 1 to 2%.
% By weight. If the amount is less than 0.5% by weight, the emulsion after phase inversion becomes unstable. If it is more than 3% by weight, foaming of the solution or the like becomes a problem.

The dispersion stabilizer applies heat to the emulsion after the phase inversion, and evaporates the solvent from the droplets of the resin solution, thereby contributing to the stabilization of the suspension state (solid-liquid). Preferred dispersion stabilizers are polymeric dispersion stabilizers. As the polymeric dispersion stabilizer, methyl cellulose,
Hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, gum arabic and the like can be mentioned. The addition amount is 0.1 to 10% by weight of the solution II, preferably 0.5 to 10% by weight.
5 If the amount is less than 0.1% by weight, it does not contribute to stabilization, and if it is more than 10% by weight, there is a problem that the viscosity of the solution becomes too large.

Solution II has a lower viscosity than solution I. Preferably it is 1-20 cp, more preferably 1-10 cp. The solution II is used in a combination having a viscosity difference of 20 cp or less, preferably 10 cp or less with the solution I. And the difference is greater than 20 cp, in order to obtain the desired particle size, and requires vigorous high-speed stirring, therefore a high shear force is added to the solution, particle size distribution is wide emulsion is formed. As a result, the obtained toner particles contain a large amount of fine powder.

The solution II obtained as described above is added to the solution I with stirring. At the beginning of the addition, the solution II is dispersed and turbid in the form of particles in the solution I. The state is shown in FIG. In FIG. 1, solution II corresponds to a water droplet, and solution I corresponds to an oil phase. As the addition progresses and the amount of solution II increases, both phases pass through the states shown in FIGS.
The phase inversion phenomenon occurs, and finally the state shown in FIG. The addition amount of solution II or stirring conditions, temperature conditions or the magnitude of each viscosity of solutions I and II, the difference in viscosity between the two solutions, and the like, are as follows. More preferably, the thickness is adjusted to 3 to 8 μm. Usually, the ratio of the solutions I and II is 100 parts by weight of the former and 100 to 100 parts by weight of the latter.
500 parts by weight, more preferably 100 to 300 parts by weight. Emulsion preparation temperature is normal temperature, usually 5-35
° C, preferably 15 to 25 ° C. According to the present invention, it is easy to prepare an emulsion having a relatively uniform particle size by using the solution I and the solution II as described above. The phase inversion may be performed by increasing the amount of the solution II added, but may be performed by changing the temperature of the emulsion, adding a surfactant having a high HLB separately, or adding a hydrophilic solvent. You may.

To obtain toner particles from the emulsion, the emulsion obtained as described above is heated to a temperature not lower than the boiling point of solution I and not higher than the boiling point of solution II, or by heating to the azeotropic temperature of both. The solvent is removed from the resin solution particles. Upon removal of the solvent, the toner particles become solution I
A suspension in I is obtained. The toner particles are separated from the solution II by means such as filtration, washed with a solvent that does not dissolve the resin, and dried to have an average particle size of several μm to 9 μm.
It is possible to obtain toner particles having a uniform particle size of μm. Hereinafter, the present invention will be described with reference to examples.

Reference Example 1 A polyester resin (Mn: 298) was added to 400 parts by weight of methylene chloride.
0, Mw / Mn: 3.4) 100 parts by weight were dissolved to obtain a solution having a viscosity of 9.3 cp. The resulting solution is referred to as solution I. Distilled water 100
Parts by weight, polyvinyl alcohol (2% aqueous solution; viscosity 15cp)
2 parts by weight and 2 parts by weight of sodium laurate were mixed to obtain a solution having a viscosity of 4.1 cp. The resulting solution is referred to as solution II.

The viscosity is a value measured at 23 ° C. using an Ostwald viscometer. The viscosities described below show the same measured values unless otherwise specified.

A homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.)
The solution II was gradually added to 50 parts by volume of the solution I under stirring at 0 ° C. and 4000 rpm. Solution II
Phase inversion occurred when 00 parts by volume were added. At that point the addition of solution II was stopped and stirring continued for another 10 minutes.
After completion of the stirring, the obtained dispersion was poured into distilled water. The system was stirred at about 500 rpm while maintaining the temperature at 50 ° C. to evaporate the methylene chloride.

Subsequently, the particles in the aqueous solution were filtered out. Further, the washing was repeated to wash away the dispersion stabilizer and the like adhering to the particle surface. The obtained particles were dried under vacuum to obtain resin particles.

Reference Example 2 A polyester resin (Mn: 298) was added to 400 parts by weight of methylene chloride.
0, Mw / Mn: 3.4) 100 parts by weight were dissolved to obtain a solution having a viscosity of 9.3 cp. This solution is referred to as solution I. 100 parts by weight of distilled water, 1 part by weight of methylcellulose (2% aqueous solution; viscosity 15 cp) and 1 part by weight of sodium laurate were mixed to give a viscosity of 5.
An 8 cp solution was obtained. This solution is referred to as solution II.

Other than using these solutions I and II,
Resin particles were obtained in the same manner as in Reference Example 1 .

Reference Example 3 In Reference Example 1, the order of adding the solution II to the solution I was as follows.
Reference Example 1 except that the order of adding solution I to solution II was changed.
In the same manner as described above, resin particles were prepared. That is, 100 parts by volume of the solution I was gradually added to 50 parts by volume of the solution II stirred at 20 ° C. and 4000 rpm using a homomixer (manufactured by Tokushu Kika Kogyo KK). After the addition was completed, stirring was continued for another 10 minutes. After completion of the stirring, the obtained dispersion was poured into distilled water. The system was stirred at about 500 rpm while maintaining the temperature at 50 ° C. to evaporate the methylene chloride.

Subsequently, the particles in the aqueous solution were filtered out. Further, the washing was repeated to wash away the dispersion stabilizer and the like adhering to the particle surface. The obtained particles are vacuum dried,
Resin particles were obtained.

Reference Example 4 The same solutions I and II used in Reference Example 2 were prepared. 50 parts by volume of the solution I and 100 parts by volume of the solution II were simultaneously placed in a beaker, and stirred at 20 ° C. and 4000 rpm for 10 minutes using a homomixer (manufactured by Tokushu Kika Kogyo KK). After stirring,
The obtained dispersion was put into distilled water. The system was stirred at about 500 rpm while maintaining the temperature at 50 ° C. to evaporate the methylene chloride.

Subsequently, the particles in the aqueous solution were filtered out. Further, the washing was repeated to wash away the dispersion stabilizer and the like adhering to the particle surface. The obtained particles were dried under vacuum to obtain resin particles.

Example 1 400 parts by weight of methylene chloride 100 parts by weight of polyester resin (Mn: 2980, Mw / Mn: 3.4, softening point: 103 ° C., Tg: 58 ° C.) 5 parts by weight of phthalocyanine pigment Charge control agent: Bontron (P -51): (manufactured by Orient Chemical Co., Ltd.) 3 parts by weight The above materials were mixed and uniformly dispersed and dissolved. The resulting solution is referred to as solution I. Solution I had a viscosity of 10.2 cp.

100 parts by weight of distilled water 2 parts by weight of polyvinyl alcohol (polymerization degree: about 500) 2 parts by weight of sodium laurate The above materials were mixed and uniformly dissolved. The resulting solution is referred to as solution II. Solution II had a viscosity of 4.1 cp.

The homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) is 20
Solution II was gradually added to 50 parts by volume of solution I under stirring at 4000 rpm. Solution II
When 00 parts by volume were added, phase inversion occurred. at the time,
The addition of solution II was stopped and stirring was continued for another 10 minutes.
After completion of the stirring, the obtained dispersion was poured into distilled water. The system was stirred at about 500 rpm while maintaining the temperature at 50 ° C. to evaporate the methylene chloride.

Subsequently, the particles in the aqueous solution were filtered out. Further, the washing was repeated to wash away the dispersion stabilizer and the like adhering to the particle surface. The obtained particles were vacuum-dried to obtain a toner.

Example 2 400 parts by weight of methylene chloride 100 parts by weight of polyester resin (Mn: 2980, Mw / Mn: 3.4, softening point: 103 ° C., Tg: 58 ° C.) 5 parts by weight of phthalocyanine pigment Charge control agent: Bontron (P -51): (manufactured by Orient Chemical Co., Ltd.) 3 parts by weight The above materials were mixed and uniformly dispersed and dissolved. The resulting solution is referred to as solution I. Solution I had a viscosity of 10.2 cp.

Distilled water 100 parts by weight Methylcellulose (2% aqueous solution; 15 cp 1 part by weight sodium lauryl sulfate 2 parts by weight) The above materials were mixed and uniformly dissolved, and the obtained solution was designated as solution II. It was 8 cp.

Toner particles were obtained in the same manner as in Example I except that these solutions I and II were used.

Comparative Example 1 In Example 1 , the order of adding the solution II to the solution I was as follows.
Example 1 except that the order in which solution I was added to solution II was changed
Was performed in the same manner as described above to prepare a toner.

That is, 100 parts by volume of the solution I was homogenized with a homomixer (manufactured by Tokushu Kika Kogyo KK) at 20 ° C. and 4000 r.
The solution was slowly added to 50 parts by volume of solution II under stirring at pm. After the addition was completed, stirring was continued for another 10 minutes. After completion of the stirring, the obtained dispersion was poured into distilled water. The system was stirred at about 500 rpm while maintaining the temperature at 50 ° C. to evaporate the methylene chloride.

Subsequently, the particles in the aqueous solution were filtered out. Further, the washing was repeated to wash away the dispersion stabilizer and the like adhering to the particle surface. The obtained particles are vacuum dried,
Toner particles were obtained.

Comparative Example 2 The same solution I and solution II used in Example 2 were prepared. 50 parts by volume of the solution I and 100 parts by volume of the solution II were simultaneously placed in a beaker, and stirred at 20 ° C. and 4000 rpm for 10 minutes using a homomixer (manufactured by Tokushu Kika Kogyo KK). After stirring,
The obtained dispersion was put into distilled water. The system was stirred at about 500 rpm while maintaining the temperature at 50 ° C. to evaporate the methylene chloride.

Subsequently, the particles in the aqueous solution were filtered out. Further, the washing was repeated to wash away the dispersion stabilizer and the like adhering to the particle surface. The obtained particles are vacuum dried,
Toner particles were obtained.

Particle Size Evaluation The particle size distribution of the particles obtained in Reference Examples 1 to 4, Examples 1 and 2 and Comparative Examples 1 and 2 was measured with SALD-1100 (manufactured by Shimadzu Corporation). The results are shown in Table 1 below.

[0040]

[Table 1]

As is evident from Table 1, the production of particles utilizing the phase inversion phenomenon results in less fine powder and coarse powder.
Particles having a sharp particle size distribution can be obtained.

Evaluation of charging rise First, a carrier was manufactured as follows. 100 parts by weight of polyester resin (softening point 123 ° C, glass transition point 65 ° C, AV23, OHV40) Fe-Zn based ferrite fine particles 500 parts by weight MPP-2 (manufactured by TDK) Carbon black (MA # 8; manufactured by Mitsubishi Chemical Corporation) 2 parts by weight The above-mentioned materials are sufficiently mixed and pulverized with a Henschel mixer,
Next, cylinder section 180 ° C, cylinder head section 170 ° C
Were melted and kneaded by using an extruder kneader set to 1.
After cooling the kneaded material, coarsely pulverized using a feather mill,
Further, after finely pulverizing with a jet mill, the mixture was classified using a classifier to obtain a carrier having an average particle size of 60 μm.

The carrier obtained was mixed with the toners obtained in Examples 1 and 2 and Comparative Examples 1 and 2 at a ratio of 10% by weight of the toner. 30 g of the obtained mixture was put in a 50 cc polyethylene bottle, and was rotationally mixed at 1200 rpm for 30 minutes with a paint conditioner (manufactured by Red Devil Co.). The charge amount at that time is measured, and the charge amount at the time of initial mixing is used.

Thereafter, the toner and the carrier are separated by applying an electric field, and 10% by weight of new toner is added to the separated carrier.
, And 30 g of the mixture was placed in a 50 cc polyethylene bottle and rotated at 1200 rpm. The charge amount of the toner at that time is defined as the charge amount at the time of additional mixing. The above results are summarized in Table 2 below.

[0045]

[Table 2]

From Table 2, it can be seen that as the amount of fine powder of 2 μm or less or the size of large particles of 16 μm or more increases, the charge amount at the time of additional mixing tends to be smaller than the charge amount at the time of initial mixing. This indicates that the toner charge amount decreases as the number of copies actually increases.
This is probably because the fine powder clings to the carrier and cannot be separated from the carrier, which hinders the contact between the additional toner and the carrier. If the large particle size is large, the mixing and agitation with the carrier during the additional mixing becomes worse compared to the initial stage, so that the toner charge amount decreases.

[0047]

According to the present invention, toner particles having an average particle diameter of 3 to 9 μm and having a uniform particle diameter can be obtained by utilizing the phase inversion phenomenon of the emulsion.

[Brief description of the drawings]

FIG. 1 is a schematic view conceptually showing a turbid state of a W / O emulsion.

FIG. 2 is a schematic diagram conceptually showing a phase inversion process.

FIG. 3 is a schematic view conceptually showing a phase inversion process.

FIG. 4 is a schematic diagram conceptually showing a turbid state of an O / W emulsion.

────────────────────────────────────────────────── ─── Continuation of the front page Examiner Yuki Fukuda (56) References JP-A-1-15842 (JP, A) JP-A-3-221137 (JP, A) JP-A-52-3653 (JP, A) JP-A-1-180562 (JP, A) JP-A-2-153361 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9/08

Claims (3)

(57) [Claims] 1. An aqueous solution II is added to a resin solution I containing a resin and a colorant in a hydrophobic solvent as a medium to cause phase inversion, thereby forming an O / W emulsion.
And a method for producing toner particles by removing the solvent of the solution II, wherein the resin solution I has a viscosity of 3 to 30 cp at 23 ° C. The aqueous solution II having a viscosity of 1 to 20 cp higher than the viscosity ;
Has a viscosity of 1 to 20 cp at 23 ° C. 2. The method according to claim 1, wherein the solution I further contains a charge control agent. 3. The method for producing toner particles according to claim 1, wherein the toner particles have an average particle size of 9 μm or less.