JPH0151189B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing toner. Conventionally, toners have generally been produced by dissolving and mixing colorants and other additives in a thermoplastic resin, uniformly dispersing the mixture, and then using a pulverizer or a classifier to produce toners having a desired particle size. Although this manufacturing method can produce fairly good toners, it does have certain limitations. That is, the toner obtained using the pulverization method must have some brittleness so that the material is somewhat susceptible to pulverization. However, if something 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 is not cost effective, which increases the cost. Furthermore, in some cases, the toner is further pulverized in the developing device of a copying machine. Furthermore, when a material with a low melting point is used to improve heat fixability, a fusion phenomenon occurs in a crushing device or a classification device, and continuous production may not be possible. Other requirements for the toner are that it has triboelectric properties suitable for development, that it forms an excellent image;
The characteristics include no change in performance when left standing, no solidification (blocking, etc.), appropriate heat or pressure fixing properties, and no contamination of the surface of the photoreceptor. Particularly in fusing, an offset phenomenon in which toner adheres to the fusing roller and is retransferred onto the next copy paper is always a problem. To prevent this, a release agent such as silicone oil is used on the fusing roller. It has been practiced to apply However, in recent years, toners have been made to contain polyolefins such as polypropylene and polyethylene, and the fixing roller is not coated with a release agent.
Methods to prevent offset have become common. However, this method is not sufficiently effective in preventing offset, requires an auxiliary fixing roller cleaning device, and cannot perform mass copying without maintenance. Therefore, attempts have been made to add a larger amount of polyolefin or to use a polyolefin with a lower melting point, but these have resulted in fusion in the crusher or classifier, or the polyolefin with a lower melting point is exposed to the surface of the toner. This causes blocking and poor fluidity, which significantly reduces developability. Therefore, in order to overcome the drawbacks of the pulverization method, a method for producing toner using a suspension polymerization method was proposed. That is, since it does not involve any pulverization process, it does not need to be brittle, and its spherical shape has excellent fluidity, which results in uniform friction and electrification. However, it is technically difficult to carry out polymerization in a stable suspended system without coalescence, and to obtain fine polymer particles with a uniform particle size distribution through polymerization. Therefore, when suspension polymerizing a polymerizable monomer system in water, a suspension stabilizer is used to prevent coalescence of polymer particles as the polymerization progresses. Suspension stabilizers generally include poorly soluble, finely powdered inorganic compounds such as BaSO ₄ , CaSO ₄ , MgCO ₃ , BaCO ₃ ,
Slightly soluble salts such as CaCO ₃ and Ca ₃ (PO ₄ ) ₂ , inorganic polymers such as diatomaceous earth, silicic acid, clay, and talc, powders of metal oxides, water-soluble polymers such as polyvinyl alcohol, gelatin, starch, etc. There is. Furthermore, stirring also affects the stability of polymerization and particle size. High-speed stirring stabilizes polymerization, but the particles become smaller than necessary. Conversely, low-speed stirring may result in gelation and particles may not be obtained. Therefore, it is necessary to choose appropriate conditions. However, even with these methods, the particle size that satisfies the toner, that is, the number average diameter of 10 μ
It is difficult to obtain fine particles of ~20μ.
This is because, in the end, there are not enough ways to prevent union. Therefore, in the combination of a polymerizable monomer and an inorganic dispersant, the interface of the polymerizable monomer particles is cationically charged by the addition of a cationic polymerizable monomer or a poorly water-soluble organic amine compound; The inorganic dispersant is charged with an anion opposite to that of the polymerizable monomer particles, and therefore, the inorganic dispersant completely and uniformly covers the surface of the polymerizable monomer particles with strong ionic bonds, resulting in coalescence. A method has been proposed to prevent this and obtain fine particles with a number average diameter of about 10 to 20 μm. However, even with this method, the particle size cannot be said to be sufficiently satisfactory as a toner. This is because it is more preferable that the toner particle size distribution is narrower. In other words, when the particle size becomes uniform, the amount of charge on each particle becomes almost the same, and therefore a stable image can be obtained. The narrower the particle size distribution, the more stable the image, the better the reproducibility of fine lines, and the less fog there will be. Furthermore, in this method, the toner has fixability,
It is extremely difficult to satisfy the conflicting properties of offset properties, blocking properties, and developability. To improve fixation and offset properties,
It is effective to include hydrocarbon compounds such as paraffin and polyolefin, but toner produced by this method has anionic groups gathered on the particle surface, but is almost a homogeneous polymer as a whole, so it is difficult to heat the toner. In order to improve fixing properties, the molecular weight is reduced,
When Tg is lowered, blocking properties deteriorate,
Moreover, it is also reflected in development, resulting in poor image quality. On the other hand, if the molecular weight is increased or crosslinked in order to improve the blocking property, then the heat fixing property deteriorates, resulting in a vicious cycle. Therefore, a system containing one or more types of polymerizable monomers, if necessary, a dye, a polymer, and other additives is suspended in a dispersion medium in which an anionic dispersant is dispersed. A method has been proposed in which the polymerizable monomer contains a cationic polymerizable monomer or a poorly water-soluble organic amine compound and a hydrocarbon compound in the polymerization system. Without being bound by any theory, in the above method, when a cationic polymerizable monomer or a poorly water-soluble organic amine compound is added to the monomer system, these substances collect on the surface of the suspended particles and form monomers. It is thought that the particles are slightly distributed from the mass system into the dispersion medium system, making the interface between the particles and the dispersion medium uncertain, and as a result, the suspended particles become slightly unstable, so the particle size distribution cannot be said to be quite narrow. It will be done. On the other hand, as in the present invention described later, a cationic styrene copolymer of styrene or a styrene derivative and a nitrogen-containing vinyl monomer is used as the cationic substance, and the cationic styrene copolymer is When dissolved in a monomer system containing styrene or styrene derivatives and suspended in a dispersion medium system containing an anionic dispersant, the cationic copolymer assembled on the surface of the suspended particles is , monomer system) into the dispersion medium system.
This is because it has a high molecular weight. Therefore, the interface between the suspended particles becomes firm and stable, making it easier for the particles to align. Since the cationic styrene copolymer in particular gathers on the surface of the suspended particles, the resulting particles take on a kind of shell-like form and become pseudo-capsules. That is, irrespective of the initial polymerization of the polymerizable monomer, a resin having a desired degree of polymerization can be used as the cationic styrene copolymer for the shell. Therefore, in the present invention, when producing toner particles having a pseudo-capsule structure, the interior is polymerized to have a relatively low molecular weight and excellent fixing properties, and the cationic styrene-based shell portion is polymerized. As the polymer, a resin having a relatively high molecular weight and excellent blocking properties, developability, and abrasion resistance can be used. Therefore, a system containing one or more types of polymerizable monomers, dyes and pigments, polymers, and other additives if necessary, is suspended in a dispersion medium in which an anionic dispersant is dispersed, and polymerization is carried out. It has been proposed that the polymerizable monomer contains a cationic styrenic copolymer and a hydrocarbon compound and then polymerizes the polymerizable monomer. By the above method, it is possible to obtain a toner that is practically satisfactory.
However, there are many additional demands placed on toners. That is, it is strongly desired to carry out fixing in a more energy-saving manner without degrading the developability, blocking, fluidity, and abrasion resistance properties. In this case, since the hydrocarbon compound is hydrophobic and has a low molecular weight, it is difficult to mix with the cationic styrenic copolymer, which has polar groups and has a large molecular weight. It is pushed into the inside of the toner without coming out. Then, it comes out from the inside during fixing, improving fixing properties.
Significantly improves offset properties. At this time, the hydrocarbon compound is thought to function as a plasticizer, a lubricant, and an oil effect. The hydrocarbon compounds used here include paraffin and polyolefin having 6 or more carbon atoms, such as paraffin wax (Nippon Oil),
Parafine wax (Nippon Seiso), Microwax (Nippon Oil), Microcrystalline wax (Nippon Seiso), PE-130 (Hoechst), Mitsui Hiwax 110P (Mitsui Petrochemical), Mitsui Hiwax 220P (Mitsui Petrochemical) ), Mitsui Hiwatux 660P
(Mitsui Petrochemical), etc., and particularly preferably,
It is a parafine. As mentioned above, the toner obtained here has excellent developability, fixability, offset resistance, and also excellent blocking resistance. However, although the above toner is slightly
Although it is hygroscopic and causes no practical problems, it is desirable to further improve the developability. This hygroscopicity is due to the fact that the inorganic dispersant is hydrophilic and remains attached to the toner surface even when filtered and washed with water.In order to improve the developability of the toner, it is necessary to remove this inorganic dispersant. There is. Therefore, an object of the present invention is to provide a toner with better developability and better moisture resistance. Specifically, the present invention provides a cationic styrenic copolymer of styrene or a styrene derivative and a nitrogen-containing vinyl monomer, which contains styrene or a styrene derivative as a polymerizable monomer and is a hydrocarbon compound. dissolved in a monomer system containing
The heated monomer system in which the cationic styrenic copolymer is dissolved is suspended in the heated dispersion medium system containing the anionic dispersant and polymerized to form pseudo capsules. The present invention relates to a method for producing a toner, which comprises producing structured polymer particles and treating the polymer particles with a silane coupling agent or a titanate coupling agent to produce a toner. In other words, 0.1% or more of a silane coupling agent or a titanium coupling agent based on the polymer weight is added to the polymer, and the inorganic substance on the surface of the polymer is reacted with the coupling agent, thereby coupling the dispersant on the surface of the polymer. It is. At this time, if the coupling agent used is 0.1% or less, the inorganic dispersant will not be coupled sufficiently, and unreacted substances will remain on the toner surface. Silane coupling agents used in the present invention include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, vinyltriacetoxysilane, N-β(aminoethyl)-γ
-aminopropylmethoxysilane, N-β(aminoethyl)-γ-aminopropylmethyldimethoxysilane, N-β-(N, vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane , γ
-(2-aminoethyl)aminopropyltrimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltrichlorosilane,
γ-methacrylocypropyltrimethoxysilane,
γ-glycidoxypropyltrimethoxysilane,
γ-mercaptotrimethoxysilane, vinyltriacetoxysilane, γ-chloropropyltrimethoxysilane, hexamethyldisilane, vinyltris(methoxyethoxy)silane, γ-anilinopropyltrimethoxysilane, octadecyldimethyl [3-(trimethoxysilyl) ) propyl] ammonium chloride, γ-mercaptopropylmethyldimethoxysilane, etc. Further, titanate coupling agents that can be used in the present invention include isopropyl triinsostearoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl tris(dioctylpyrophosphate) titanate,
Tetraisopropylbis(dioctylphosphite) titanate, Tetraoctylbis(ditridecylphosphite) titanate, Tetra(2,2
-Diallyloxymethyl-1-butyl)bis(di-tolyldecyl)phosphite titanate, bis(dioctylpyrophosphate)oxyacetate titanate, bis(dioctylpyrophosphate)ethylene titanate, isopropyltrioctinonortitanate, isopropyldimethacryliso Examples include stearoyl titanate and isopropyl isostearoyl diactyl titanate. These coupling agents can be treated by dissolving and dispersing them in an aqueous solution and immersing them in a conventional manner, or by dissolving them in a small amount of water and an organic solvent containing a hydrolysis catalyst and immersing them in the solution, or by dissolving them in an aqueous solution or organic solvent. Methods such as spraying a liquid may be used, but the method is not limited thereto. It is also possible to remove the silica from the polymer particles with an alkali and then treat them using the above method. The cationic styrenic polymer used in the present invention includes dimethylaminoethyl methacrylate,
Dimethylaminoethyl acrylate, diethylaminoethyl methacrylate, diethylaminoethyl acrylate, N-n-butoxyacrylamide, trimethylammonium chloride, diacetone acrylamide, acrylamide, N-vinylcarbazole, vinylpyridine, 2-vinylimidazole, 2-hydroxy-3-methacrylate Examples include cationic styrenic copolymers of nitrogen-containing monomers such as oxypropyl, trimethylammonium chloride, or quaternized versions of these nitrogens, and the following styrene or styrene derivatives. Preferably, the cationic copolymer has a weight average molecular weight of 50,000 to 150,000, as shown in the Examples below. Styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene, 2,4- Dimethylstyrene, p-n-butylstyrene, p-tert-butylstyrene, p-n
- Styrene and derivatives thereof such as hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene. Examples of the polymerizable monomers used in the present invention include the following, and one or more of these may be used. Further, one or more of these polymers may be contained in the polymerizable monomer. Styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene, 2,4- Dimethylstyrene, p-n-butylstyrene, p-tert-butylstyrene, p-n
- Styrene and derivatives thereof such as hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene. Examples of 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, and propionic acid. Vinyl, vinyl esters such as vinyl benzoate and vinyl butyrate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n methacrylate
-α-methylene aliphatic monocarboxylic acid esters such as butyl, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate; acrylic Methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate,
2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, methyl isopropenyl ketone; N such as N-vinylpyrrole, N-vinylcarbazole, N-vinylindole, N-vinylpyrrolidone, etc.
-Vinyl compounds; vinylnaphthalenes; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, acrylamide, and the like. Polymerization initiators used in the present invention include oxycarbonate, kyumene hydroperoxide,
2,4-dichlorylbenzoyl peroxide,
Lauroyl peroxide and the like can be used. In the present invention, a crosslinking agent may be used to form a crosslinked polymer. For example, vinylbenzene, divinylnaphthalene and derivatives thereof; diethylene carboxylic acid esters such as diethylene glycol methacrylate, triethylene glycol methacrylate, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate; 1,2-propylene glycol, 1,3 - A general crosslinking agent such as butanediol can be used as appropriate. As the dispersant that can be used in the present invention, known anionic dispersants can be used. Examples include water-soluble polymers such as polyvinyl alcohol, partially saponified polyvinyl alcohol, and other vinyl alcohol copolymers, and finely powdered inorganic compounds such as colloidal silica, such as Aerosil 200 or 300. As dyes and pigments used in the present invention, commonly known dyes and pigments can be used. moreover,
Carbon black and magnetic materials can also be used. In particular, magnetic materials should be surface-treated. The suspension method uses a monomer system in which a polymerization initiator, cationic styrenic copolymer, styrene or styrene derivative, additives, dyes and pigments, crosslinking agents, etc. are uniformly dissolved or dispersed, and a suspension stabilizer is added. The stirring speed is adjusted so that the preferably monomer droplets, which are dispersed in the dispersed phase, i.e. the continuous phase, by a conventional stirrer or homomixer, homogenizer, etc., have the desired toner particle size, generally less than 30 μm. After adjusting the time, stirring may be carried out to such an extent that sedimentation of the particles is prevented so that the state is substantially maintained by the action of the dispersion stabilizer. Polymerization is carried out by appropriately setting the polymerization temperature. After the reaction is completed, the generated toner particles are put into an aqueous solution of a silane coupling agent or titanate coupling agent of a predetermined concentration, stirred at room temperature for 1 to 3 hours, filtered, washed with water, and dried to obtain a toner. . All known methods can be used to develop this toner. For example, two-component development methods such as the cascade method, magnetic brush method, and microtoning method; one-component development methods containing magnetic materials such as conductive one-component development method, insulating one-component development method, and jumping development method; powder Examples include cloud method and fur brush method; non-magnetic one-component development method in which toner is held on a toner carrier by electrostatic force and transported to a developing section for development. Example 1 Styrene monomer 200g Styrene-dimethylaminoethyl methacrylate copolymer 10g (monomer ratio 8:2, = 50000) Parafine wax 130〓 (manufactured by Nippon Seiro Co., Ltd.)
8g azobisisobutyronitrile 10g phthalocyanine blue 10g are heated to 70°C, and the copolymer, paraffin wax, initiator, etc. are dissolved in the styrene monomer.
This was mixed for about 5 minutes while heating to about 60° C. in a container equipped with a high shear mixing device such as TK Homo Mixer (manufactured by Tokushu Kika Kogyo). Separately, 4 g of Aerosil #200 was dispersed in 1000 c.c. of water, heated to about 60°C, and the above monomer system was added to the mixture while stirring with a TK homomixer, followed by stirring at 4000 rpm for about 1 hour. Thereafter, this mixed system was stirred with paddle blade stirring to complete the polymerization. After this, isopropyl triisostearoyl titanate (manufactured by Ajinomoto Co., Ltd.)
Add 3g of TTS2-3099) and stir at room temperature.
The mixture was reacted, coupled with a dispersant, washed with water, filtered, and dried to obtain a toner having a pseudo-capsule structure. The obtained toner had a number average diameter of 9.1 μm, a number distribution of 18% of particles of 6.35 μm or less, and a volume distribution of 1% of particles of 20.2 μm or more.

【table】

[Table] Images were produced by mixing iron powder carrier EFV250/400 (Japan Iron Powder) and toner to a toner concentration of 10 wt%, using the developer as a developer, and performing reversal development using a copying machine NP5500. Further, the fixing property test was conducted using a PC-10 fixing device to which no mold release agent such as silicone oil was applied. Fluidity was determined by visual inspection in an actual developing device. Further, toners that are not coupled with a titanate coupling agent have extremely high image density, but are undesirable because fog becomes noticeable. Example 2 Styrene monomer 180g Butyl acrylate monomer 20g Styrene-diethylaminoethyl methacrylate copolymer 10g (monomer ratio 9:1, = 100000) Parafine wax 150〓 (Nippon Seiro) 8g Azobisisobutyronitrile 10g BL-250 (manufactured by Titanium Industries) 60g ASA-30 (manufactured by Mitsubishi Kasei) 1g The above materials were prepared in the same manner as in Example 1, and N-β-
A toner was obtained which was coupled with 5 g of (N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane salt (Toray Silicone SZ-6035). The obtained toner had a number average diameter of 8.7 μm, a number distribution of 20% of particles of 6.35 μm or less, and a volume distribution of 0% of particles of 20.2 μm or more.

[Table] Images were printed using a PC-10 copier, and the same machine's fixing device was used for fixing. Also, with the toner that was not coupled with SZ-6032, the image became a little lighter. Example 3 Styrene monomer 200g Copolymer of styrene and dimethylaminoethyl methacrylate 5% quaternized product with benzyl chloride 10g (monomer ratio 9:1, = 50000) Azobisisobutyronitrile 10g Parafine wax 155〓 ( A toner was prepared in the same manner as in Example 1 using 10 g of Nippon Seiso, 1 g of divinylbenzene, and 10 g of phthalocyanine green.

【table】

[Table] Image production is achieved by using toner containing magnetic material in the toner without mixing carrier particles, which is held on a toner carrier by electrostatic force and transported to the developing section for development. This was done using a method of developing toner that does not contain any toner. The fixing properties were tested using a hot roller fixing device of a CP-10 copying machine. Also, the toner that was not treated with a silane coupling agent had similar image properties to the comparative toner in Example 2. Example 4 Styrene monomer 100g Styrene-dimethylaminoethyl methacrylate copolymer 10g (monomer ratio 9:1, = 150000) Parafine wax 155〓 (Nippon Seiro) 100g V-65 (Wako Pure Chemical Industries) 10g Phthalocyanine blue 10g Divinylbenzene 1g A toner was prepared in the same manner as in Example 1.

【table】

[Table] The developing method here is the same as in Example 3. Fixing properties were tested using a pressure fixing device using a rigid roller. Further, the toner whose surface was not coupled with a titanate coupling agent had a thin image and poor toner coating on the developer sleeve.

Claims (1)

[Claims] 1. A cationic styrenic copolymer of styrene or a styrene derivative and a nitrogen-containing vinyl monomer, which contains styrene or a styrene derivative as a polymerizable monomer and also contains a hydrocarbon compound. Dissolved in the monomer system, mixed while heating,
A heated monomer system in which a cationic styrenic copolymer is dissolved is suspended in a heated dispersion medium containing an anionic dispersant and polymerized to form polymer particles having a pseudo-capsule structure. generate,
A method for producing a toner, comprising treating the polymer particles with a silane coupling agent or a titanate coupling agent to produce a toner. 2. The method for producing a toner according to claim 1, wherein the cationic styrenic copolymer has a weight average molecular weight of 50,000 to 150,000. 3. The method for producing a toner according to claim 1 or 2, wherein the anionic dispersant is colloidal silica. 4. The method for producing a toner according to any one of claims 1 to 3, wherein the monomer system contains a crosslinking agent.