JPS5962870A - Production of toner - Google Patents

Abstract

PURPOSE:To obtain a toner which is stable during storage, does not solidify and has the low m. p. suitable for heat fixing by using a polymn. method of dispersing a toner material in a dispersion medium, polymerizing the same to form polymer particles, adsorbing a monomer on the polymer particles and growing the same. CONSTITUTION:A toner material contg. a monomer of a synthetic resin, a polymn. initiator and a coloring material is dispersed in a dispersion medium hardly compatible with said monomer, and is polymerized to polymer particles. A toner is used by using a polymn. method of adsorbing a monomer system having the glass transition temp. higher than the glass transition temp. of the polymer particles on the polymer particles and growing the same. The dispersion medium prepd. by incorporating a stabilizer, for example, PVA, gelatin, methyl cellulose or the like in an aq. phase is used preferably in an about 0.1-10wt% range. The polymn. is accomplished generally at the temp. set at 70-90 deg.C. An alpha, beta unsatd. monomer such as styrene and a vinyl monomer such as ethylene are used as the monomer of a synthetic resin. Either oil soluble or water soluble polymn. initiator is usable in the method of growth, and a typical free radical initiator and redox catalyst are used.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a toner for developing an electrostatic a-image or the like.

Traditionally, toners are typically melt-mixed into thermoplastic resins,
After evenly distributed! , a toner having a desired particle size has been produced using a pulverizer classifier. Although this method of manufacturing can produce fairly good toners, it does have certain limitations, namely the range of selection of materials for the toner. for example,
The resin pigment dispersion must be sufficiently brittle to be comminuted at economically viable production rates.

Because of this requirement, the resin pigment dispersion is sufficiently brittle that when it is actually pulverized at high speed, particles with a wide range of particle sizes are likely to be formed. The problem arises that Such highly brittle grains are often further pulverized or powdered when used for development in copying machines. Other requirements for the toner include being stable on storage, not solidifying, having triboelectric properties suitable for development, forming good images, not coating or staining the photoreceptor; These requirements are combined with the additional requirements imposed on this toner formation process, in particular by having a low melting point suitable for thermal fusing.

The electrostatic image developing toner obtained by suspension polymerization overcomes the drawbacks of the pulverization method. In other words, there is no need for brittleness as there is no pulverization process involved, and the toner has excellent fluidity due to its spherical shape, and by appropriately controlling polymerization or using a crosslinking agent, a toner with excellent heat fixing properties can be obtained. be able to.

Therefore, attempts have been made to directly produce toners for electrostatic charge development by emulsification or suspension polymerization. These polymerization methods have been proposed in JP-A-53-17735 and other publications. These toners are obtained directly by dispersing a monomer polymerization initiator, a coloring agent, a magnetic material, and other components in water.

In other words, since there is no pulverization process involved, there is no need for brittleness, and since the toner is spherical, it has excellent fluidity, and by appropriately controlling polymerization or using crosslinking agents, toners with excellent heat fixing properties can be produced. can be obtained.

However, the requirements for electronic photography are extremely strict.
There are competing requirements for it to be stable on storage, not to solidify, and to have a low melting point suitable for heat fixing.

The present invention provides a novel method for producing toner for developing electrostatic images, etc., which satisfies such requirements.

Zono% %'/ then Korot' 1, composition: 14 Jf
single fr, Li form.

A toner using a polymerization method in which a toner containing a colorant and a polymerization initiator 2 is dispersed in a dispersion medium that is almost incompatible with the single polymer, polymerized to form polymer particles, and grown by the polymerization. It is in the manufacturing method.

When growing polymer particles, the glass inversion temperature of the primary polymer particles that are stably dispersed in water is much higher than that of the seed polymer particles. It is injected and adsorbed while carefully controlling the oat system. To obtain the best results at this time, it is important to carefully control the rate of single compound addition; if the addition rate is too low, the polymerization time will be unduly prolonged; It's too much and the great ruins +
Not only are the particles produced, but the particles of the scale tend to coalesce, resulting in the formation of agglomerates.

Generally, monomer should be added at the same rate as it is adsorbed by the particles.

Therefore, preferably the Tg of the seed polymer particles is 80.
℃ or below, the Tg of the monomer system used for growth is above 80 ℃. The surface of the seed polymer particles adsorbs the monomer, causing the surface to swell. If this swelling occurs only on the surface, it will be coated with monomer and polymerized by the initiator, so it will have a smooth surface that is not contaminated with colorants or magnetic substances, or with little stain. I can do it.

Furthermore, by adjusting the amount of monomer in the seed polymer particles, it is possible to control the particle size to a desired value.

The seed polymer particles include a synthetic resin monolayer, a polymerization initiator,
A monomeric toner material in which a colorant, magnetic substance, additives, etc. are uniformly dissolved or dispersed is dispersed in an aqueous phase containing a suspension stabilizer, that is, a continuous phase, using an ordinary stirrer, homomixer, homogenizer, etc. urge Preferably the monomer droplets are of the desired toner particle size, typically 30 t
Adjust the stirring speed and time so that the particles have a size of less than Good. Polymerization temperature is 50°C or higher, generally 70°C.
Polymerization is carried out by setting the temperature uL to 90°C.

Suitable dispersion media used in the present invention include, for example, any suitable stabilizer, such as polyvinyl alcohol, gelatin, methyl cellulose, methyl hydropropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, polyacrylic acid and their like. Salts, starches, gum alginates, zein, casein, tricalcium phosphate, Merck, barium sulfate, bentonite, aluminum hydroxide, ferric hydroxide, titanium hydroxide, thorium hydroxide, etc. are included in the aqueous phase. can.

The stabilizer is stabilized in the continuous phase and preferably ranges from about 0.1 to about 10% by weight.

In addition, for fine dispersion of the inorganic dispersant, 0.001
It is also possible to use surfactants in the range of 0.1% by weight. This is to promote the intended action of the above-mentioned dispersion stabilizer, and specific examples thereof include sodium dodecylbenzenesulfonate, sodium tetradecylsulfate, sodium pentadecylsulfate, sodium octylsulfate, and allyl-alkyl-polymerizate. Sodium ethersulfonate, sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, potassium stearate, calcium oleate, 3,3'-disulfonodiphenylurea-4
,4'-diazo-bis-amino-8-naphthol-6-
Sodium sulfonate, orthocarpoxybenzene-azodimethylanili/, 2.2', 5.5'-tetramethyl-triphenylmethane-4,4'-diazo-
Bis-β-nanotol-sodium disulfonate, among others.

In addition, monomers that are easily water-soluble cause emulsion polymerization in water at the same time, and the resulting suspension polymer becomes contaminated with small emulsion polymers. It is also good to prevent emulsion polymerization in the aqueous phase. Furthermore, in order to increase the viscosity of the medium and prevent coalescence of particles, glycerin, glycol, etc. may be added to the water. In addition, NaCl 5KC1, Na, S
It is also possible to use a salt 1 such as O4.

As the polymerization initiator, any suitable polymerization initiator such as azobisinbutyronitrile (AIBN), benzoyl peroxide, methyl ethyl ketone peroxide,
Monomer polymerization can be carried out using isopropyl peroxycarbonate, kinimen hydroperoxide, 2,4-dichlorylpenzoyl peroxide, lauroyl peroxide, and the like. Generally, about 0.5 to 5 parts of initiator by weight of the monomers is sufficient.

Polymerization temperature and coagulation are usually 50°C to 120°C, but uniform polymerization is more likely to occur at lower temperatures.

As specific examples of synthetic resin monomers, the following are applicable to the present invention. Examples of α-β unsaturated monomers include styrene, 0-methylstyrene, m-methylstyrene, p-methylstyrene, p-ethylstyrene, 2.4-
Dimethylstyrene, p-n-butylstyrene, p-t
ert-butylstyrene, pn-hexylstyrene,
p-n-octylstyrene, p-n-nonylstyrene,
Examples include styrene and its derivatives such as p -n-decylstyrene, p -n -°dodecylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, and 3.4=dichlorostyrene, among which styrene Monomers are most preferred. Examples of other vinyl monomers include ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide, and vinyl fluoride; vinyl acetate, vinyl propionate,
Vinyl esters such as vinyl benzoate and vinyl butyrate; methyl acrylate, ethyl acrylate, acrylic rR
n-butyl, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate,
2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate,
Methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, inbutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, meccrylic acid
2-ethylhexyl, stearyl methacrylate, phenyl methacrylate, dimethylamine ethyl methacrylate,
α-methylene aliphatic monocarboxylic acid esters such as diethylamine ethyl methacrylate; acrylonitrile) IJ
Acrylic acid or methacrylic acid derivatives such as chloride, meccrylonitrile, and acrylamide; Vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, and vinyl inobutyl ether; Vinyl ketones such as vinyl methyl, ketone, vinyl hexyl ketone, and methyl isoprovenyl ketone; M; N-vinyl compounds such as N-vinylpyrrole, N-vinylcarbasol, N-vinylind9-ol, and N-vinylpyrrolidone; vinylnaphthalenes and the like can be mentioned.

The polymer according to the present invention is a compound having two or more double bonds in which a crosslinking agent is used during polymerization. -g, diethylene glycol methacrylate,
Diethylene glycol methacrylate, trimethylolpropane triacrylate, 1-normethacrylate, t-butylaminoethyl methacrylate, tetraethylene glycol dimethacrylate, 1,3-fringiol dimethane 1-root, etc. diethylene carboxylic acids; All divinyl compounds such as ester, N,N-divinyl-niline, divinyl ether, divinyl sulfide, divinyl sulfone, and compounds having 3 or more vinyl groups, etc."IX. It is returned either as a single piece or as a mixture. Furthermore, ethylene glycol, triethylene glycol,
1.2-Flopylene glycol-x-/l/, 1. 3-propylene chrysanthemum: I-A/, 1. 4-butanediol, neopentyl glycol, 1,4-butenedimer, 1,
Dihydric alcohols such as 4-bis(hydroxymethyl)cyclohexane, bisphenol A1 hydrogenated bisphenol A, polyoxyethylenated bisphenol A1 polyoxypropylenated bisphenol A; maleic acid, fumaric acid, mev-x-= ye, '/Traconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarponic acid, cono-phosphoric acid, adipic acid, sepatic acid, malonic acid, anhydrides of these dibasic acids and their derivatives such as esters with lower alcohols; trivalent or higher alcohols such as glycerin, trimethylolpropane, pentaerythritol, and trivalent or higher carboxylic acids such as trimellitic acid and hyromellitic acid. It is used in the present invention as a crosslinking agent.

The amount of such a crosslinking agent added to the monomer is selected to be in the range of 0.005 to 20% by weight, preferably 0.1 to 5% by weight. If the amount added is too large, the toner will not melt and will tend to lose its fixing properties as a toner.

If the amount of shavings is too low, the characteristics of toner such as durability, shelf life,
Endurance 111! It becomes difficult to impart characteristics such as porosity, and the molecular weight distribution of the polymer expands due to crosslinking, especially in thermal roll fixing/i''1 method photocopiers. This makes it difficult to achieve the effect of preventing this.

As the coloring agent, any one selected from pigments, dyes, etc. can be used. For example, carbon black, nigrosine dye, oil black, etc. can be used alone or in combination. A magnetic material may be used as a coloring agent.

The magnetic material used in the toner material may be any material as long as it is strongly magnetized in that direction by a magnetic field. Magnephyto is good. Typical magnetic or magnetic materials include metals such as iron, iron, and nickel; aluminum,
To Konokuruto, steel, lead, magnesium, nickel, tin, zinc, antimony, beryllium, bismuth, and iotomium. , alloys and mixtures of metals such as calcium, manganese, selenium, titanium, tungsten, vanadium; aluminum oxide, iron oxide, iron oxide, ('+'2
Metal compounds including metal oxides such as nickel oxide, ηIL lead, titanium oxide and magnesium oxide; refractory terrarides such as vanadium tinide and chromium tenide; carbides such as tungsten carbide and silica carbide; ferrite and Mixtures thereof can be used.

As the monomer used in the method for producing polymer particles, compounds similar to the monomer used in the seed polymerization described above can be used.

The polymerization initiator used in the growth method can be either oil-soluble or water-soluble. Typical free radical initiators and redox catalysts are used as the polymerization initiator. For example, free radical initiators include hydrogen peroxide, peracetic acid, t-butyl hydroperoxide, di-tert-butyl peroxide, dibenzoyl peroxide, perbenzoic acid, tert-butyl peracetate, azobisisobutyronitrile. , ammonium persulfate, sodium persulfate, potassium persulfate, potassium perphosphate, etc.

Redox catalyst systems include sodium persulfate-sodium formaldehyde sulfoxylate, cumene hydroperoxide-sodium bisulfite, and hydrogen peroxide-ascorbic acid. Initiator concentrations generally range from 0.3 to 0.8 wt% based on monomer.

In the growth process, surfactants can be used to stabilize the polymerized particles. For example, anionic activators include potassium palmitate, potassium stearate, potassium caprate, potassium oleate, sodium dodecyl sulfonate, sodium lauryl L, sodium rosinate, sodium argyl sulfosuccinate
2 esters etc. Examples of cationic activators include long silver quaternary amine salts. Nonionic activators include lysyllic acid, lauric acid, lysyllic acid, ethylene oxide condensate of caproic acid, oleyl alcohol, cetyl alcohol,
Ethylene oxide condensates such as lauryl alcohol, etc.

The above surfactants can be used alone or in combination. Surfactant: Generally, it is good to have a concentration below the critical micellar content (CMC), but it may be added in an amount above the CMC for the purpose of increasing the emulsion particle size or stabilizing the particles.However, At this time, it is also possible to use a polymerization inhibitor such as NH, SCN (ammonium thiocyanide) or copper salt to prevent emulsion polymerization in the aqueous phase and suppress the generation of new powder.

After the reaction is completed, the produced toner particles are collected by a suitable method such as washing, filtration, decantation, centrifugation, etc., and dried.

[Actually 1j Example 1. ] 320g of styrene, 80y of ethyl acrylate and Fissie A.-diameter 0.4μ BET specific surface area 6.0 m2/
240f magnetite with a particle size of y)Ei)T-
1000 and petrolactam oxide metal salt (0X manufactured by Kuchiki Seinade)
-0851) 24 f and the chromium acetesterate complex 8y were mixed for about 20 minutes in a container equipped with a high-shear mixing device such as a TK-homomixer (specially manufactured by 100%).
Mix uniformly for minutes.

During this time, the temperature rose to about 50°C. During this time, the magnetite was dispersed in the styrene monomer. 3(M
' lauroyl peroxide was stirred and mixed into a styrene monomer containing magnetite. 9. 600y of water in which polyvinyl alcohol of Of was dissolved was kept at 70°C, and the upper % (2%) slurry was put into a homomixer while stirring, and stirred at 4000 rpm for 30 minutes.The reaction mixture system was stirred with a paddle blade. The polymerization was completed by stirring and the glass transition temperature of this product was 67°C.

Thereafter, styrene 1009 (glass transition temperature: 00'O) in which the benzoyl peroxide of ``y'' was dissolved was poured into 21Q 1tij and then polymerized for 3 hours to complete the polymerization.

Washed with water and dried, average number of larvae 10.1μ, number distribution: 6
．． 15 strokes below 35 μ, 20 in volume distribution. zμ or more 1ch (
A toner was obtained using a Coulter counter with a 100μ aperture. It was confirmed by a scanning electron microscope that it had a flat surface.

This toner was applied to a commercially available dry type electrophotographic copying machine NP-400R.
I made both with E. As a result, 1t without fogging
I was able to see a clear image of the 1st person.

Image density is 1.20 with solid black area and reflection density 6I.
I got it. The toner properties were also satisfactory, particularly in fluidity and durability of continuous image formation.Example 80y of styrene, 20g of n-butyl acrylate, 0.2g of trimethylolpropane triacrylate, β-type phthalocyanine pigment 10jF.

and 2F chromium acetylsalicylate complex were uniformly dispersed and mixed using a ball mill. Thereafter, 32-2,2'-azobis-(2,4-dimethylvaleronitrile) was added and dissolved. 3f tricalcium phosphate and 0.05
The above slurry was poured into 300f of water An to which sodium dodecylbenzenesulfonate was added while stirring using a TK-homogenizer at a stirring speed of 5000 rpm. Thereafter, polymerization was carried out at 60°C for 7 hours to complete the polymerization reaction. The Noblas transition temperature of this material was 55°C. After that, the temperature was raised to 70°C and styrene 50 in which 2f of 2.2'-azobisisobutyronitrile was dissolved was heated to 70°C.
y (glass transition temperature: 100°C) was added dropwise over 4 hours, followed by polymerization for 5 hours to complete the polymerization. After cooling,
After drying, a toner having a number average diameter of 9.2 μm (using a Coulter counter with an aperture of 100 μm) was obtained.

This toner was applied to a commercially available dry type electrophotographic copying machine NP-5000.
The image was produced using a machine. As a result, a clear image without fogging was obtained.

+11 petitioner Canon Co., Ltd.

Claims (1)

[Scope of Claims] A toner containing two synthetic resin monomers, a polymerization initiator, and a coloring agent is dispersed in a dispersion medium that is almost incompatible with the monomers and polymerized to form polymer particles. . A method for producing a toner using a polymerization method in which a monomer having a glass transition temperature higher than the glass transition temperature of the polymer particles is adsorbed onto the polymer particles and allowed to grow.