JPH03168763A - Production of color toner for electrophotography - Google Patents

Abstract

PURPOSE:To substantially prevent the formation of fine particles and uncolored particles and to relatively uniformize the grain size distribution of the toner by suspending and dispersing a polymerizable compsn. consisting of specific chromatic pigments, a radical polymerizable monomer and a radical polymn. initiator into an aq. soln. and polymerizing the mixture. CONSTITUTION:The polymerizable compsn. consisting of the chromatic pigments having <=2.0% moisture content under resting conditions of 20 deg.C and 65% RH, the radical polymerizable monomer and the radical polymn. initiator is suspended and dispersed into the aq. soln. and thereafter, the mixture is polymerized. The chromatic pigments to be used in this case have the moisture content as low as <=2.0% and, therefore, the chromatic pigments are relatively well dispersed into the radical polymerizable monomer and the polymn. is relatively stably executed. The control of the grain size of the colored resin during the polymn. stage is stably executed in a 1 to 30mum range adequate for the toner and the grain size distribution is uniformly maintained. The intrusion of the fine particles is further prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing color toner used in electrophotography, and more specifically, the present invention relates to a method for producing a color toner used in electrophotography, and more particularly, a colorant is contained in the polymerization process of a fixing resin, and the particle size is The present invention relates to a method for producing toner at once with a uniform particle size distribution within a range suitable for.

(Prior Art) In the field of electrophotography, toners are used to visualize electrostatic charge images. The toner particles are made by blending additives such as a colorant and a charge control agent in a resin medium, and have a certain particle size range, for example, a particle size range of 1 to 30 μm.

By the way, as a method for producing such a toner, a method is known in which the toner is produced simultaneously with the polymerization of a toner resin. That is, in this production method, a water-insoluble monomer,
A soluble polymerization initiator is dissolved in this, additives such as a coloring agent are added, and this composition is suspended by high-speed stirring in an aqueous solution containing a dispersant, and this is polymerized to form a colored polymer. This is a method for producing coalesced particles.

(Problem to be Solved by the Invention) However, in such a suspension polymerization method, the diameter of the toner obtained is determined by the state of suspension of the composite in water, and for example, the diameter of the toner obtained is determined by the state of stirring in water. The fifR distribution of toner is very likely to become a-broad.

In addition, toner produced by the suspension polymerization method has the disadvantage that it is difficult to avoid the inclusion of fine particles at a certain ratio, and such fine particles are particles made of polymers that do not contain toner additives such as colorants. Since they have different characteristics from toner particles, even if they are mixed in a small amount, they cause toner scattering and fogging during development, and they also tend to cause a decrease in toner fluidity.

In particular, when this suspension polymerization method is applied to the production of color toners, the particle size distribution is broad and the above-mentioned fine particles are likely to be produced. In other words, the water content of chromatic pigments is much higher than that of carbon black, which is commonly used in the production of black toners. They have the disadvantage that they tend to dissolve into water and tend to cause unstable polymerization.

The present invention has been made focusing on the above-mentioned actual situation,
The object thereof is to provide a toner for electrophotography in which fine particles and uncolored particles are hardly generated and the particle size distribution of the toner is relatively uniform, and a method for producing the same. An object of the present invention is to provide an electrophotographic color toner having excellent environmental resistance such as moisture resistance, and a method for producing the same.

(Means for Solving the Problems) The method for producing a color toner for electrophotography of the present invention includes
A polymerizable composition consisting of a chromatic pigment whose water content is 2.0% or less when left standing at 65% RH, a radically polymerizable monomer, and a radical polymerization initiator is suspended in an aqueous solution. It is characterized in that it is turbidly dispersed and then polymerized, thereby achieving the above macroscopic properties.

Another method of producing a color toner for electrophotography according to the present invention is to add a polymerizable toner containing the above-mentioned chromatic pigment, a radically polymerizable monomer, and a radical polymerization initiator to an aqueous solution in which tricalcium phosphate is dissolved. The method is characterized in that the composite is suspended and dispersed, then an alkali hydroxide is added to the aqueous solution, and then polymerized, thereby achieving the above object.

(Function) When producing color toners by the suspension polymerization method, the water content of the chromatic pigment used is very low at 2.0% or less, so this chromatic pigment is relatively contained in the radically polymerizable monomer. It is well dispersed and polymerization is relatively stable.

In particular, tricalcium phosphate, a poorly water-soluble inorganic salt, was used as a dispersion stabilizer, and this was dissolved in an acidic aqueous solution in advance, and then alkali hydroxide was added to precipitate tricalcium phosphate. By performing a polymerization reaction in
The Ti degree of the colored resin during the polymerization process is stably controlled within the range of 1 to 30 μm, which is suitable for toner, and the particle size distribution is also maintained uniformly, further preventing the incorporation of fine particles.

(Preferred Embodiments of the Invention) (a) Radically polymerizable monomer: The radically polymerizable monomer used in the present invention is such that the resulting polymer has the fixing properties and electrodetection properties required for the toner. One kind or a combination of two or more kinds of monomers having an ethylenic uncelled fO group are used.

Examples of such monomers include monovinyl aromatic monomers, acrylic monomers, vinyl ester monomers, vinyl ether monomers, diolefin monomers, and monoolefin monomers. be.

The above monovinyl aromatic monomer has a general formula of the following formula (
1) are used, specifically styrene,
α-methylstyrene, vinyltoluene, α-chlorostyrene, 0-chlorostyrene, ha-chloro-a-styrene, p-
Examples include chlorostyrene, p-ethylstyrene, sodium styrene sulfonate, and dipinylbenzene, and these can be used alone or in combination of two or more.

In the formula, R1 represents a hydrogen atom, a lower alkyl group, or a halogen atom, and R2 represents a hydrogen atom, a lower alkyl group, a halogen atom, an alkoxy group, an ami/i, a nitoσ group, a vinyl group, or a carboxyl group.

As the above-mentioned acrylic monomer, those whose general formula is represented by the following formula (2) are used, and specifically, acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, acrylic acid -2-Ethylhexyl, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, hexyl methacrylate, 2-methacrylate
-ethylhexyl, ethyl β-hydroxyacrylate,
γ-hydroxyprobyl acrylate, δ-hydroxybutyl acrylate, β-hydroxyethyl methacrylate,
Examples include γ-aminoprobyl acrylate, γ-N-N-diethylaminoprobyl acrylate, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, etc., and these can be used alone or in combination of two or more. .

R2 GH2 leakage C -Co-0 -R, ・-
(2) In the formula, R3 represents a hydrogen atom or a lower alkyl group, and ? 4 represents a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms, a hydroxyalkyl group, a vinyl ester group, or an aminoalkyl group.

The general formula of the above vinyl ester monomer is the following formula (
Those represented by 3) are used, and specific examples include vinyl formate, vinyl acetate, and vinyl brobionate.

CH■-CM 0 In the formula, R represents a hydrogen atom or a lower alkyl group.

The general formula for the above vinyl ether monomer is the following formula (
Those represented by 4) are used, and specific examples include nihabinyl methyl ether, pyruethyl ether, vinyl-n-butyl ether, vinyl phenyl ether, and vinyl cyclohexyl ether.

CHi = CH I O -R, - (4) In the formula, Ra represents a hydrocarbon group having 1 to 12 carbon atoms.

The general formula of the above diolefin monomer is the following formula (5
) are used, specifically putadiene,
Examples include inbreen and chloroprene.

During the ceremony, R? ．． ．． Rss Each Rs independently represents a hydrogen atom, a lower alkyl group, or a halogen atom.

The general formula for the above monoolefin monomer is the following formula (
6) are used, and specific examples include ethylene, propylene, inbutylene, phytene-t, pentene-1,4-methylbentene-t, etc.

In the formula, RI9 and R's each independently represent a hydrogen atom or a lower alkyl group.

(b) Radical polymerization initiator: The radical polymerization initiator used in the present invention includes azo compounds such as azopisisobutyronitrile, cumene hydroperoxide, t-butyl hydroperoxide, dicumyl peroxide, di-t-butyl Examples include peroxides such as peroxide, benzoyl peroxide, and lauroyl peroxide, and those soluble in the above monomers are particularly preferred.

The amount of these polymerization initiators to be blended may be a commonly used amount, and is generally preferably 0.1 to loM amount % based on the monomers charged.

(C) Chromatic pigment: The chromatic pigment used in the present invention can be used at room temperature and humidity (20
``C・65%RH) Moisture content under standing conditions is 2.0%
Below, the content is particularly 1.0% or less. Examples of such chromatic pigments include the following.

Brilliant Ca FC pure (0.1
24%, 20℃・65%), Permanent Re
d FNG (0.144%, 20℃・65%), B
rilliant Sc 2201 (0.160%,
20℃・65%), Pigwent Seal SL
(0.124%, 20”C・65%), Brill
iant Ca FBD (0.174%, 20°C
- 65%), BrilliantCa 7001
(0.391%, 20°C-65%), Ket Re
d 309 (0.583%, 20℃・65%)
, Ket Red 326 (0.592%, 20'C
・65%) (all of the above are manufactured by Sanyo Shiki Co., Ltd.), etc.

These pigments may be used alone or in combination of two or more. The amount of chromatic pigment added is 1 to 30 parts by weight per 100 parts by weight of the fixing resin in order to obtain sufficient toner image density.
Parts by weight are preferred, and 2 to 20 parts by weight are more preferred.

(d) Other compounding agents: In the present invention, in addition to the above-mentioned chromatic pigments, additive components that are preferably contained in the toner include (a) a radically polymerizable monomer, (b) a polymerization initiator and (C) it can be used together with a chromatic pigment.

For example, for use as a two-component system, charge control agents known per se, such as nigrosine base (CISO4
5) Oil-soluble dyes such as oil black (CI26150) and spirone black; naphthenic acid, salicylic acid,
Metal soaps that are metal salts of octylic acid, higher fatty acids, resin acids such as manganese, iron, cobalt, nickel, lead, zinc, cerium, calcium, etc.; metal-containing azo dyes; pyrimidine compounds; and metal chelates of alkylsalicylic acids are used. Among these, alcohol-soluble ones are particularly preferably used. These charge control agents are used in the fixing resin 10.
0.1 to 5 parts by weight per 0 parts by weight are preferably used.

Furthermore, the above-mentioned toner can be blended with various compounding agents known per se that are used in this field.

For example, as an anti-offset agent, various waxes such as low molecular weight polypropylene, low molecular weight polyethylene, and paraffin wax; olefin f having 4 or more carbon atoms; fatty acid amide; silicone oil, etc. can be used as the fixing resin 1.
It is preferably contained in an amount of 0.5 to 15 parts by weight per O O heavy plate.

Using the above materials, the color toner for electrophotography of the present invention is produced in the following manner.

A colored composition is obtained by suspending and dispersing the above-mentioned low water content chromatic pigment, a radically polymerizable monomer, and a radical polymerization initiator in an aqueous solution, and then polymerizes it. here,
It is preferable to use the above tricalcium phosphate as a dispersion stabilizer, and it is preferable to add an acid to the aqueous solution in advance to make it acidic.

Examples of acids that can be used include mineral acids such as hydrochloric acid, sulfuric acid, and nitric acid, with hydrochloric acid being particularly preferred. Tricalcium phosphate will be dissolved in the acid aqueous solution. Tricalcium phosphate may be dissolved in an acid aqueous solution in advance, or may be added together with monomers and the like.

Tricalcium phosphate is preferably used in an amount of 1 to 20 parts by weight, particularly preferably 5 to 10 parts by weight, per 100 parts by weight of the total ffi of the radically polymerizable monomer, radical polymerization initiator, and chromatic pigment. The mineral acid is used in such an amount that all of the tricalcium phosphate can be dissolved, and generally the IiEfl ratio to tricalcium phosphate is preferably 1:10 to 1:50, particularly 1:1 to 1:10. is preferred.

In this case, the above-mentioned wax, charge control agent, etc. are added as necessary. In this state, the separation phase is formed as an oil phase. The amount of other additives to be added is preferably 5 to 200 parts by weight, particularly 10 to 100 parts by weight, per 100 parts by weight of the acid aqueous solution in which tricalcium phosphate is dissolved. The amount of the radical initiator to be blended is a so-called catalytic amount, and is generally preferably used in an amount of 0.1 to 10% by weight based on the monomers charged.

The chromatic pigment may be blended in the amount contained in the toner resin, and is generally suitably in the range of 1 to 30% by weight, particularly 2 to 20% by weight, based on the amount of monomer charged.

Further, in the present invention, it is preferable to mix a surfactant into the acid aqueous solution in advance before adding and mixing components such as the above-mentioned radically polymerizable monomers. The surfactant acts as a dispersion stabilizer in the oil droplet formation process described below.

Anionic surfactants are advantageously used as the dispersion stabilizer, and suitable examples thereof are as follows.

Fatty acid salts such as sodium oleate and castor oil potassium soap; Higher alcohol sulfate ester salts such as sodium lauryl sulfate and sodium cetyl sulfate; Alkylaryl sulfonates such as sodium dodecylbenzenesulfonates; Sodium alkylnaphthalene sulfonates; Sodium salt of β-naphthalene sulfonic acid formalin condensate, etc.; derivatives of naphthalene sulfonates; dialkyl sulfosuccinates; dialkyl phosphates;
Polyoxyethylene alkyl ether sulfates: bosooxyethylene alkyl ether sulfate triethanolamines; polyoxyethylene alkyl phenol ether sulfate m, etc.

The amount of this surfactant used may be small; for example, 100% of water
It is used within the range of 0.5 part by weight or less, preferably 0.1 part by weight or less.

In the present invention, LiOH, κOf{
, an alkali hydroxide such as NaOH.

This precipitates tricalcium phosphate and forms a very fine suspended oil.

The precipitation reaction of tricalcium phosphate at this time is expressed, for example, by the following formula.

3CaCl2 + 2H3PO4 + 5NaOH-C
ai(POa)2↓+61JaCl+ 5H20 In this case, if the amount of alkali hydroxide added is adjusted so that the pH of the reaction system is in the range of 7 to 8, the volume will increase even if the amount of surfactant used is reduced. A toner having a small particle size with an average particle size of 10 μl or less can be obtained. In addition, by adjusting the amount of alkali hydroxide added so that the pH of the reaction system is 11 or higher, the resulting toner has an extremely sharp particle size distribution.
In other words, it is important that the particle size is uniform.

Next, a radical polymerization reaction is carried out in the state in which the above-mentioned fine particle suspension is shaped.

The polymerization temperature and time may be those known in the art, and generally polymerization at a temperature of 40 to 100"C for 1 to 50 hours is sufficient. The stirring of the reaction system should be moderate enough to produce a homogeneous reaction as a whole. Stirring may be sufficient, and the polymerization may be carried out by replacing the reaction system with an inert gas such as nitrogen in order to prevent inhibition of polymerization by oxygen.

At this time, if the polymerization reaction is carried out under conditions where pll is 7 to 8, there are advantages in that the reaction efficiency is improved and unreacted residual monomers can be reduced.

Furthermore, when the polymerization reaction is carried out under conditions where pll[ is 11 or more,
For example, the advantage of suppressing the formation of emulsion polymerized particles with a particle size of 1 μl or less is violated. This pH adjustment can be easily carried out, for example, by further adding the alkali hydroxide described above.

Since the polymerized product after the reaction is obtained in the form of granules having a particle size within the above-mentioned range, the raw particles are filtered, washed with water etc. if necessary, and dried to obtain colored particles for toner.

If necessary, the colored particles for toner are sprinkled with Rikibon black, hydrophobic silica, etc. to form a final toner.

(Effect of the invention) According to the present invention, the particle size is 1 to 30 μm, especially 10 μm.
A toner having a sharp particle size distribution within the following particle size range can be obtained by the suspension polymerization method.

In particular, this toner does not substantially contain emulsion polymer particles having a fine particle size. Therefore, the toner obtained by the method of the present invention has excellent fluidity, chargeability, moisture resistance, etc., and has the remarkable advantage of not causing toner scattering or fogging.

(Implementation N) Hereinafter, the present invention will be specifically explained based on Examples.

衷JLI! Add 7 parts by weight of tricalcium silicate to 670 parts by weight of distilled water, and add 23 parts by weight of hydrochloric acid while dispersing with a stirring stirrer.
After adding parts by weight and sufficiently dissolving, HaDBS0.
17 parts by weight of a 2% solution was added.

Short styrene...82 parts by weight 2-ethylhexyl methacrylate...18 parts by weight Brilliant Ca FC pure (water content 0.124%, 20'C 65%)...5 parts by weight Dipinylbenzene...・0. 2 parts by weight diethylene glycol dimethacrylate...t. S weight part AIBN (azopisisobutyronitrile)...0.
32 parts by weight ADVN・2. Add 1 part of 5 parts of the above oil phase to the aqueous phase and stir for 3 minutes at llooorpm using a homo mixer made by Tokushu Kika Co., Ltd. to fully disperse the oil phase, and then continue stirring in the same way to add 4N-NaOH.
The pH of rice was adjusted to 9 by adding 65 parts by weight of tricalcium phosphate (Ca3PO4), and then 20 parts by weight was added.
After stirring for 1 minute, the average particle size was 1 o. A 4μ-sized cloudy oil droplet was obtained.

This suspension was polymerized at 80° C. for 2 hours under a nitrogen stream to obtain a polymer. The liquid was separated into a precipitate and a supernatant liquid, and the precipitate was treated with dilute acid, washed with water, and then dried to obtain a red toner. The supernatant liquid was almost transparent.

When the particle size of the obtained red toner was measured using a coal counter, the volume average particle size I)ss was 1O. 4μ
In seagulls, the ratio of D25/D75 is l. It showed a sharp particle size distribution of s. Further, the residual mo/mer content of the obtained red toner was 0.73%.

Next, the above red toner and ferrite carrier are combined and
Stir to obtain a developer, and use this developer as DC manufactured by Sanda Kogyo ■.
-1205 and conducted a copying test, there was no scattering or blurring, and clear images with good background and resolution were obtained.

Permaner+t Red is Oikeen's main chromatic pigment.
FNG (moisture content 0.144%, 20″C・65%)
A red toner was obtained in the same manner as in Example 1 except that .

When the physical properties of the obtained red toner were measured in the same manner as in Example 1, the volume average particle diameter D5l+ was 9.9 μm and the D25/DTS ratio was 1.49, indicating a sharp particle size distribution. Indicated. The residual mo/mer content of the obtained toner was 0.79%.

In addition, the above red toner and ferrite carrier may be mixed.
Stir to obtain a developer, and use this developer as DC manufactured by Sanda Kogyo ■.
-1205 and performed a copying test, there was no scattering or fogging, and clear images with good solid areas and resolution were obtained.

As a chromatic pigment, Brilliant Ca RS
A red toner was obtained in the same manner as in Example 1 except that (water content: 0.765%, 20° C., 65%) was used.

When the physical properties of the obtained red toner were measured in the same manner as in Example 1, the volume average particle diameter D5B was 10.6μ, the ratio D25/D75 was 1.8, and the particle size was slightly broad. It became a degree distribution. The residual monomer component of the obtained toner was 0.93%.

Further, the above toner and ferrite carrier are mixed and stirred to obtain a developer, and this developer is mixed with DC-1 manufactured by Sanda Kogyo Co., Ltd.
When I carried out a copying test with the printer installed on the 205, scattering and fogging were observed.

that's all

Claims (1)

[Claims] 1. Moisture content under standing conditions of 20°C and 65% RH is 2.
Electrophotography, characterized in that a polymerizable composition comprising 0% or less of a chromatic pigment, a radically polymerizable monomer, and a radical polymerization initiator is polymerized after being suspended and dispersed in an aqueous solution. Method of manufacturing color toner. 2. Suspending and dispersing a polymerizable composition comprising the chromatic pigment according to claim 1, a radically polymerizable monomer, and a radical polymerization initiator in an aqueous solution in which tricalcium phosphate is dissolved,
A method for producing a color toner for electrophotography, which comprises adding an alkali hydroxide to the aqueous solution and then polymerizing it.