JPS62141566A - Production of suspension-polymerized toner - Google Patents

Abstract

PURPOSE:To improve fluidity and developing characteristics by subjecting polymer particles contg. a coloring agent obtd. by separating the same from an aq. medium for >=30min at 35-75 deg.C after a suspension polymn. stage. CONSTITUTION:A mixture composed of a monomer, polymn. initiator and other additives such as coloring material, magnetic material, resin, release agent, crosslinking agent and charge controlling agent is stirred and mixed in an aq. medium, by which the mixture is pulverized and is polymerized in the pulverized particle state. The resultant polymer particles are separated from the aq. solvent and thereafter the particles are subjected to the heating treatment for >=30min at 35 deg.C-75 deg.C which is near Tg (Tg+ or -30 deg.C) of the resin for the toner. The heating temp. and heating time are adequately determined within the range of 35-75 deg.C and >=30min where the flocculation and adhesion of the polymer particles to each other does not arise.

Description

[Detailed Description of the Invention] [Technical Field] The present invention is applicable to electrophotography, silent copying, electrostatic printing, etc. The present invention relates to a method for producing a toner used for visualizing (!), and more specifically to a method for producing a so-called polymerized toner produced by one-suspension polymerization.

[Background technology]

Conventionally, toners have generally been produced by melt-mixing colorants and other additives in a thermoplastic resin, uniformly dispersing the mixture, and then using a pulverizer, classifier, etc., to produce a toner having a desired particle size.

However, this production requires multiple waves of energy in the melting, mixing, and pulverizing processes. Also, the toner obtained using the pulverization method.

The material must have some brittleness to make it susceptible to crushing. However, if the material is too brittle, it becomes too finely powdered.

Later, in order to obtain a toner with an appropriate particle size distribution, it is necessary to cut the fine powder, which increases the cost. Therefore, a method for manufacturing a toner called a sub-basin toner by round suspension polymerization has been proposed to overcome the problems of the pulverization method. FFI toner is a mixture of a single polymer, a polymerization initiator, and other additives! It is produced by suspending it in a t22I aqueous medium and polymerizing it in the form of particles with a desired particle size. Since the resulting polymerized toner particles are spherical, they generally have better flowability than toners produced by pulverization.

In recent years, as image forming equipment such as fjl and photo machines have become more efficient and versatile, there has been an increasing demand for improved performance of toners used therein. In other words, as speed increases, a low ta point toner that fixes with low thermal energy is required.
Such toners generally have a low Tt, and currently, due to mechanical pressure in the process, toners adhere to each other and coagulate f%.
Acid 8 tends to form a layer on unexposed drums and cleaning blades. In addition, in terms of development characteristics, it is desired to have even higher speeds and even better development characteristics, and those with poor development characteristics include Capri and Ganatsuki.

Image defects such as under-concentration images are likely to occur.

The present invention provides a method for producing a toner that has improved properties required for such a toner. Furthermore,
The present invention provides a method for producing a polymerized toner, which includes a heat treatment step of the polymerized toner.

Namely, in the production of the polymerized toner of the present invention, by heat-treating the fc polymer particles obtained by removing the aqueous solvent after the completion of polymerization, a toner with improved flow #1 and development characteristics can be provided. It is something.

In the present invention, heat treatment probably improves the customization properties of the superimposed toner, in addition to removing residual superimposed toner, rearrangement of polymer chains in the toner, and increasing the number of polymer functional groups. The mechanical strength of the polymer improves due to the coordination of
In addition to further preventing this, it is presumed that the charging characteristics among the toner particles can be made more uniform.

The method for producing the polymerized toner of the present invention includes a monomer% polymerization initiator,
> A mixture of additives such as R color material, magnetic material, resin, mold release agent, crosslinking agent, charge control agent, etc. is mixed into fine particles by stirring and mixing in an aqueous medium, and the fine particle foreshadowing is By polymerizing, the obtained mottled aggregate particles are separated from the aqueous solvent, and then the particles are heated near the Tf of the toner resin (TV±
50°C). 35℃ (preferably 40℃) or higher 75
This can be achieved by heat treatment at temperatures below 0.degree. C. for 30 minutes or more.

Tf of resin used as toner resin at 75°C or higher
When heated at a temperature higher than the (glass transition point), polymer particles coagulate and form layers.

In addition, heat treatment at 35° C. in red does not produce the above-mentioned effects.

A more preferable heating temperature is 40 to 70°C, and a good 11C* heat treatment effect is achieved. Furthermore, the heating time is 5
0 minutes or more, preferably 1 hour or more.

Preferably 2 hours or more. The heating temperature and heating time are between 30 minutes and 75 degrees Celsius, as long as the polymer particles do not stick to each other.
It can be decided as appropriate.

Note that this heat treatment is performed under reduced pressure and/or while stirring the polymer particles to create voids between the particles, so that the removal of residual particles can be further accelerated. good.

The monomer i used in the present invention has a binary bond x
Seven polymers are used, such as styrene, 0-methylstyrene, p-methylstyrene, 2,4-dimenalstere, etc. Styrenes such as p-n-butylstyrene, p-tart-bunarsterene, p-n-dodecylstyrene, p-chlorostyrene, p-phenylstyrene, vinylnaphthalenes, ethylene, propylene, imbutylene, etc. Monoolefin; vinyl chloride;
Made of vinyl esters such as M vinyl, vinyl butyrate, benzene vinyl, acrylic ester, ethyl acrylic,
Acrylic Tfl n-butyl, acrylic-isobutyl,
Acrylic propyl, acrylic mn-octyl, acrylic 1-dodecyl, acrylic 2uril, acrylic fi2
-Ethylhexyl, acrylic stearyl, acrylic A'
(Jll, 2-/lolethyl, acrylic phenyl, α
- Methyl chloracrylate, methyl methacrylate, methyl methacrylate, methacrylic Hp 7 .

Biru, methacrylic (dn-butyl, methacrylic late isobutyl, methacrylic Jn-octyl, methacrylic related dodecyl, methacrylic related kryl, methacrylic related stearyl, methacrylic related phenyl, methacrylic is dimethylaminoethyl, methacrylic related ethyl ξ α-methylene fatty acid monocarboxylic esters such as noethyl, acrylic acid or methacrylic esters such as acrylonitrile, methacrylokotrile, and acrylamide: vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, and pinyl isobutyl ether ; Vinyl methyl ketone, vinyl silketone.

Vinyl ketones such as methyl isopropenyl ketone
- N-vinyl compounds such as vinylpyrrole, N-vinylcarbazole, N-vinylindole, and N-vinylpyrrolidene. You may use one or two or more of these. Furthermore, one or more polymers such as polar polymers having a polar group such as a carboxyl group, an amino group, or a substituted amino group may be contained in these polymerizable monomers.

Examples of the polymerization initiator used in the present invention include 1.

Asobisisobutyronitrile (from A to M), benzoyl peroxide, methyl ether ketone peroxide, isopropyl peroxide dicarbonate, dicarbonate/hydroperoxide, 2,4-dichlorylbenzoyl peroxide, This can be done using lauroyl peroxide or the like.

In the present invention, a suitable crosslinking agent may be used to form a crosslinked polymer. For example, divinylbenzene, divinylnaphthalene and their derivatives, such as diethylene glycol methacrylate.

Diethylene glycol methacrylate, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate and other diethylene glycol dimethacrylate % General crosslinking agents such as 1,2-glopylene glycol and 1,3-butanediol can be used as appropriate.

Examples of the colorant used in the toner include carbon black, iron, etc. These include nigrosine, benzidine yellow, quinacridone, rhodami 7B, and phthalocyanine blue. Further, in order to use the toner as a magnetic toner, magnetic powder may be included. In this case, the magnetic material also plays the role of a coloring agent. As such magnetic powder,
Substances that are magnetized when placed in a magnetic field are used, including ferromagnetic powders such as iron, cobalt, and nickel, or compounds such as magnetite, hematite, and ferrite.

The hydrocarbon compound used as a mold release agent is preferably a paraffin/polyolefin having 20 or more carbon atoms, such as paraffin wax (Nippon Oil), paraffin wax (Made in Japan), microwax (Nippon Oil), Microcrystalline wax (Japan IR Wax),
PIG-1sa (Hoechst), Mitsui Hiwax 11
There are 0P (Mikata Petrochemical), Mitsui Hiwax 220P (Mikata Petrochemical), Mitsui Hiwax 660P (Mikata Petrochemical), and paraffin is particularly preferred. Also preferably used is water-lined polyphtadiene.

During 185 polymerization! As a turbidity stabilizer, a finely powdered wood-like inorganic compound that is difficult to bathe (Ba#3e4.0a804
゜mtco, , BaC0,, OaC! O,,ca,
Monobath salts such as (po4)2: quartzite, talc,
Isolated molecules such as silicic acid, clay, and Merck; gold 1=4d compound powder; inorganic polymers treated with silane coupling agents, titanium coupling agents, zircoaluminum non-carbon coupling agents), water-soluble polymers (The material is polyvinyl alcohol, gelatin, Dam, and methylcellulose.

Ethyl cellulose, carboxymethyl cellulose, polyacrylic acid and their salts, alginates), etc. can be applied to the present invention. These turbidity stabilizers are usually 0.1 to 10
f! [Used within the scope of [.

External additives may be mixed with the toner if necessary. Examples of such external additives include lubricants such as Teflon and zinc sudearin, and sterilization aids (eg, low molecular weight polyethylene).

Gold metal oxides such as tin oxide are used as flowability imparting agents, anti-fog agents (such as colloidal silica), and tetraelectricity imparting agents.

The current disorder agent of the present invention is overused in many thalamic treatments. For example, magnetic brush JA method, cascade development method, rice 1
Method using conductive magnetic injection toner described in JI1% Patent No. & 909.258, JP-A-53-3113
Method using high-resistance magnetic toner described in Japanese Patent Publication No. 54-42141 and Japanese Patent Application Laid-open No. 35-18656
Publication No.

Examples include the method described in Publication No. 54-45027, a fur brush development method, a powder cloud method, an impression development method, and the like.

Hereinafter, the present invention will be explained in detail based on examples.

Practical Example 1 The above mixture "ir: about 6" in a container equipped with a high 4JJ power mixing device such as TK Homo
Mixing was performed for approximately 5 minutes while heating to 0°C.

At this time, the styrene-dimethyl 7-minomethyl methacrylate copolymer was previously melted in a bath of styrene monomer at a temperature of 60°C.

Separately, water 1oooccK axa/'+2Q (1 to 4
After 9 minutes, the slurry was heated to 60° C., and the above slurry was added to the TK homomixture while stirring, and stirred at 4000 rpm for about 1 hour. Thereafter, this mixed system was stirred with paddle blade stirring to complete the polymerization. After this, 4% of sodium hydroxide based on the weight of the toner was put into the polymerization reaction tank, and heated to 40°C for 6 hours at a rotation speed that did not allow the particles to settle.
After stirring, the fill and aqueous medium were removed.

The obtained polymer particles were heat-treated for about 1 hour while being stirred in a heating oven set at tM degrees - 45°C.

Silica gold was externally added to the obtained good magnetic toner, and image reproduction was carried out using an improved commercially available high-speed copying machine Hp-soo (Cannon). 1i #clear 1IIIIII! was gotten.

Furthermore, when the magnetic toner was dissolved in methyl ethyl ketone and the residual cystylene κK was measured by gas chromatography, it was hardly detected.

Example 2 Polymer particles f: rARl, prepared in the same manner as Example 1:
Heat treatment was performed at 65° C. for about 30 minutes. With the heat-treated magnetic toner (polymer particles'@:), good development results similar to those of Example 1 were obtained.

COMPARATIVE EXAMPLE One polymer particle was obtained in the same manner as in Example 1, air-dried at room temperature (about 20° C.), and then carried out. Similar to lj 1, when silica gold was externally added and the durability test was carried out, unevenness in the halftone area due to the deterioration occurred frequently compared to the magnetic toner of IN Example 1, and Ichijyuken also fogged. , it was something mysterious during the attack.

When this toner was subjected to dllJ determination of the residual styrene monomer in the same manner as in -A row 1, a significantly higher peak value than in tIi row 1 was confirmed.

Claims (1)

[Claims] (1) A suspension polymerized toner characterized in that, after the suspension polymerization step, the colorant-containing polymer particles obtained by separation from the aqueous medium are heat-treated at a temperature of 35°C to 75°C for 30 minutes or more. Production method.