JPS63158567A - Toner for developing electrostatic charge image - Google Patents

Abstract

PURPOSE:To obtain the titled toner having good dispersibility of carbon black, and to obtain an image having improved image density and image quality by polymerizing a monomer composition in the presence of the carbon black which is formed by reacting with a titanate type coupling agent in the monomer composition. CONSTITUTION:The carbon black is treated with a reaction product of the following titanate type coupling agent (A) and the following compd. (B). The component (A) is composed of the titanate type coupling agent having amino, hydroxyl or phosphate group as a functional group. The component (B) is composed of a compd. having a group capable of reacting with at least one of the functional group of the titanate type coupling agent (A), and said group is exemplified by hydroxyl carboxyl, acid anhydride, isocyanate, amino or epoxy group. Thus, a relatively long molecular chain binds to the surface of the carbon black, and the dispersibility of the carbon black is remarkably improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a toner for developing electrostatic images produced by a suspension polymerization method.

LLL Technique Conventionally, toners used in dry image forming methods such as electrophotography, electrostatic printing, and electrostatic recording are generally made by melt-mixing colorants and other additives in a thermoplastic resin to form a uniform layer. The toner is manufactured by dispersing it in a powder, pulverizing it with a pulverizer, and classifying it with a classifier to have the desired particle size (pulverization method).The toner obtained by this pulverization method has quite excellent characteristics. , it also has potential problems due to the grinding process.

That is, in a toner manufactured using this pulverization method, the material must have brittleness so that it can be easily pulverized to some extent. However, if a material that is too brittle is used, the toner becomes too finely divided and the fine particles must be removed to obtain the final toner with the appropriate particle size distribution, which increases manufacturing costs. ,
Furthermore, such toners are sometimes further pulverized in the developing device of the copying machine. In addition, if a material with a low melting point or pressure fixing material is used for the toner in order to improve heat fixing properties, the toner may fuse in the crushing device or classification device, making continuous production impossible. A situation arises.

Other requirements for the toner include having triboelectric charging properties suitable for development, forming an excellent developed image, no change in performance even when left unused, no solidification (blocking, etc.), and abrasion resistance. Examples of the requirements include having appropriate heat fixing properties or pressure fixing properties, and not contaminating the surface of the photoreceptor. Additionally, especially in the fusing process, there is always the problem of offset, where toner adheres to the heat and/or pressure fusing roller and this adhering toner is then retransferred onto the copy paper that comes into contact with the fusing roller. .

In order to prevent this offset development, a release agent such as silicone oil has conventionally been applied to the fixing roller on the side that contacts the toner image. However, in recent years, it has become common to prevent offset by containing polyolefins such as polypropylene and polyethylene in the toner, and either not applying a release agent such as silicone oil to the fixing roller, or reducing the amount of the oil applied. It came. Recently, in order to further improve the offset resistance of the toner, attempts have been made to add a larger amount of the above-mentioned polyolefin or to contain a polyolefin with a lower melting point in the toner. Since fusion is extremely likely to occur, it has been difficult to put the pulverization method into practical use.

Therefore, as a means to overcome the problems of the pulverization method, it has been proposed to produce a polymerized toner from a polymerizable 4L polymer by a suspension polymerization method.

In the conventional general suspension polymerization method, a monomer composition containing at least a colorant and a polymerizable monomer is granulated in an aqueous medium to a particle size corresponding to the toner, and the monomer composition is The radicals generated when the polymerization initiator added to the composition (or the polymerization initiator newly added to the composition) is thermally decomposed cause the polymerizable monomer to polymerize to form a polymer. , producing a polymerized toner. That is,
Since this suspension polymerization method does not include a pulverization step, the polymerized toner does not need to be brittle as in the pulverization method. Moreover, the polymerized toner has a spherical shape, excellent fluidity, and uniform triboelectric charging properties. It has excellent characteristics such as

However, carbon black, which has traditionally been widely used as a coloring agent for black toners, especially carbon black for pigments with high coloring power, has a small primary particle size, making it difficult to uniformly disperse it in polymerizable monomers. There is a problem.

In other words, in the above suspension polymerization method, polymerizability! # Mechanical kneading and dispersion of carbon black in a mass system is usually carried out using a dispersing device such as a sand mill or a crowbar mill, but there is a development in which the carbon black becomes more likely to re-agglomerate with the passage of time. For this reason, as polymerization progresses, the degree of blackness decreases due to agglomeration of carbon black particles, and uneven distribution of carbon black in or between toner particles causes uneven toner triboelectrification, resulting in a decrease in image density. It has not been possible to obtain an electrostatic image developing toner that provides images with high and stable image quality.

In order to solve these problems, Japanese Unexamined Patent Publication No. 53-1
It is also conceivable to use surface-treated carbon black with a silane treatment agent disclosed in JP-A-7736 and JP-A-56-116044, or grafted carbon black.

However, even with the use of these conventional surface-treated carbon blacks, the improvement in dispersibility in polymerized toner produced by suspension polymerization was still insufficient. There has been a strong desire for a toner for developing electrostatic images that provides the following properties.

An object of the present invention is to provide a toner for developing electrostatic images that solves the above-mentioned problems.

Another object of the present invention is to provide a toner for developing electrostatic images that has good carbon black dispersibility and provides images with excellent image density and image quality.

As a result of extensive research, the present inventors have found that it is possible to polymerize a monomer composition while allowing carbon black reacted with a titanate coupling agent to exist in the monomer composition.
It has been found that the dispersibility of the carbon black in the organic medium (carmer, its oligomer, etc.) can be maintained well before and after the suspension polymerization reaction, and that it is extremely effective in achieving the above objectives. .

The toner for developing electrostatic images of the present invention is based on such knowledge, and more specifically, the toner for developing electrostatic images of the present invention is produced by suspension polymerizing a monomer composition containing at least a polymerizable monomer and carbon black. The polymerized toner is characterized in that the carbon black is carbon black treated with a titanate coupling agent.

In the toner of the present invention having the above configuration, based on the characteristics of the titanate coupling agent bonded to the surface of carbon black, carbon black has a high affinity for organic media (e.g., polymerizable monomers, oligomers thereof, or binder resins). Since the affinity is improved and the dispersibility of carbon black in the organic medium is also significantly improved, it is presumed that a toner in which carbon black is uniformly and well dispersed in the binder resin can be obtained.

In the present invention, as the titanate coupling agent, a coupling agent (A) having a specific reactive functional group is used.
It is more preferable to use carbon black treated with a reaction product of the coupling agent (A) and another compound (B) which reacts with this functional group.

According to this preferred embodiment of the present invention, the compound (B) having the specific functional group described above is bonded to the carbon black surface via the specific titanate coupling agent (A), so that the carbon It is presumed that relatively long molecular chains are bonded to the black surface, and the dispersibility of carbon black in the organic medium can be further improved.

The present invention will be explained in more detail below. In the following description, "1 part" and "1%" expressing quantitative ratios are based on weight unless otherwise specified.

DETAILED DESCRIPTION OF THE INVENTION In the present invention, the carbon black contained in the monomer composition has its surface treated with the titanate-based coupling agent described above, so that at least a part of the surface is coated with the titanate-based coupling agent. Carbon black coated with a coupling agent is used.

The surface-treated carbon black used in the present invention is preferably obtained by the following method, but is not limited to the following method.

(Method 1) By adding a titanate coupling agent to an aqueous slurry of carbon black, and then removing water by filtration or dehydrating using a dryer, the titanate coupling agent can be easily mixed with carbon black. Surface treated carbon black is obtained.

At this time, regarding the dispersion of carbon black, before adding the titanate coupling agent, the carbon black in the aqueous slurry is dispersed using a dispersing machine such as a pearl mill or attritor, or the coupling agent is added. Afterwards, it is preferable to carry out the treatment while dispersing the carbon black using these dispersers.

Alternatively, the titanate coupling agent may be added to the aqueous dispersion medium first, and then carbon black may be added to form a slurry, and the treatment may be carried out while dispersing the carbon black using a dispersion machine such as a burr mill or attritor. good.

Further, after the above treatment, it is more preferable to remove the titanate coupling agent that is not bonded to the carbon black by washing with water or the like.

(Second method) Polymerizability 1! Also, by adding a titanate coupling agent to carbon black slurried in a polymer, the coupling agent can be suitably reacted with carbon black.

At this time, as in the first method, for dispersing carbon black into the polymerizable monomer, before adding the coupling agent, carbon black is dispersed using a dispersing machine such as a burr mill or attritor. After dispersing the carbon black into the polymerizable monomer or adding the coupling agent, it is preferable to carry out the treatment while dispersing the carbon black using these dispersers.

Alternatively, a titanate coupling agent is first added to the polymerizable monomer, and then carbon black is added to form a slurry, and the process is performed while dispersing the carbon black using a dispersing machine such as a burr mill or attritor. You can also do it.

Since the titanate coupling agent used in the present invention selectively reacts with carbon black among polymerizable monomers, this method of treatment in polymerizable monomers is simple and preferable.

Furthermore, since the above treatment is carried out in a polymerizable monomer with low viscosity, the titanate coupling agent can be easily bonded to the carbon black uniformly, and the slurry containing the treated carbon black can be easily bonded to the titanate coupling agent to the carbon black. , is preferable from the point of view that it can be used as a monomer composition as it is, and furthermore, it is preferable because it eliminates the effect of re-agglomeration of treated carbon black (by filtration and separation from a dispersion medium such as water). This is preferable from the viewpoint of the toner manufacturing process because the redispersion step can be omitted.

In the treatment with the coupling agent, it is preferable to perform the treatment under heating because carbon black can be treated in a short time.

(Third method) Benzene, toluene,
It is also possible to use an organic solvent such as xylene or cyclohexanone and treat carbon black in the same solvent as in the second method.

Further, after the reaction is completed, the titanate coupling agent that is not bonded to the carbon black may be removed by washing with these solvents.

In the present invention, the titanate-based coupling agent has at least one Ti atom at the center and this T
The i atom contains at least one hydrolyzable functional group (at least one
An organic titanium compound is used in which an organic group (at least one) having 4 or more carbon atoms is bonded.

The hydrolyzable functional group of the titanate coupling agent is
There is no particular restriction as long as it is a functional group that reacts relatively easily with active hydrogen on the surface of carbon black, but from the viewpoint of reactivity, it is preferably an alkoxy group or an acyloxy group, and more specifically, an isopropyloxy group. More preferably, they are a group, an octyloxy group, an ethylenedioxy group, or an acetyloxy group.

As the titanate coupling agent used in the present invention, commercially available ones can be used as they are, and specifically, for example, the following compounds are preferably used.

Isopropyl triisostearoyl titanate (e.g. Bren Act KR-TTS manufactured by Ajinomoto Co.), Isopropyl tridecylbenzenesulfonyl titanate (Bren Act KR-93), Isopropyl tris(dioctylpyrophosphate) titanate (Bren Act KR-383), Tetraisopropyl Bis(dioctyl phosphite) titanate (BlenAct KR-41B), Tetraoctyl bis(ditridecyl phosphite) titanate (BlenAct KR-46B), Tetra(2,2
-Diallyloxymethyl-1-butyl)bis(di-tridecyl)phosphite titanate (Blenact KR-
55), Bis(dioctyl pyrophosphate) oxyacetate titanate (Brenact KR-138S)
, bis(dioctylpyrophosphate) ethylene titanate (Brenact KR-238S), isobrobyltrioctinonortitanate (Blenact KR-25)
, Isopropyl dimethacrylylisostearoyl titanate (Brenact KR-7), Isopropyl isostearoyl diacryl titanate (
Brenact R-11), Isopropyl tri(dioctyl phosphate) titanate (Brenact KR-12), Isopropyl tricumylphenyl titanate (Brenact KR-345), Isopropyl tri(N-aminoethylaminoethyl) titanate (Brenact KR-44), dicumylphenyloxyacetate titanate (Blenact KR-1
34S), diisostearoyl ethylene titanate (Brenact KR-201), etc.

For application to the treatment of carbon black in the form of an aqueous slurry, BlenAct KR-55, BlenAct KR-55, BlenAct KR-
41B, BlenAct KR-46B, a titanate coupling agent having a hydroxyl group, or BlenAct KR-1385 amine addition salt, BlenAct KR-2
Using an amine addition salt of a titanate coupling agent containing a phosphoric acid ester, such as a 38S amine addition salt, or an acid addition salt of a titanate coupling agent having an amino group, such as an acid addition salt of BlenAct KR-44. It is preferable.

In addition, in the above, phosphoric acid refers to phosphorus pentoxide, P2O
It refers to a series of acids produced by hydration of 6 to various degrees, and is used to include pyrophosphoric acid, phosphorous acid, etc.

On the other hand, for the treatment of carbon black in a polymerizable monomer or a solvent other than water (e.g., an organic solvent), the titanate coupling agent described above can be used without any particular restriction. It is preferable to use a coupling agent from the viewpoint of improving the hydrophobicity of carbon black after treatment with a coupling agent.

The amount of titanate coupling agent added to carbon black varies depending on the particle size, surface structure, etc. of carbon black, but is 0.00 parts per 100 parts of carbon black.
It is preferable to use 5 parts to 10 parts (more preferably 0.5 parts to 5 parts).

If the amount of the titanate coupling agent added is less than 0.5 parts, it will have little effect on improving the dispersibility of carbon black, and if it exceeds 10 parts, a large amount of free coupling agent that does not bond with carbon black will be generated. I will do it.

In addition, for application to treatment with a polymerizable monomer system, coupling agents having a vinyl functional group (for example, Blenact K
R-55, Blen Act KR-7, Blen Act KR
It is particularly preferable to use -11) because at least a part of these is copolymerized with a polymerizable monomer, thereby further improving the dispersibility of carbon black.

The state of dispersion of carbon black in the produced polymerized toner can be determined by directly observing the toner particles with an optical microscope.

In a preferred embodiment of the present invention, a titanate coupling agent (A) having an amino group, a hydroxyl group, or a phosphate group is used as the titanate coupling agent, and the coupling agent (A) and the amino group, etc. It is preferable to treat carbon black with a reaction product of compound (B) having a functional group capable of reacting with the functional group of carbon black.

In this case, by making the molecular chain of the titanate coupling agent bonded to the carbon black surface longer,
The dispersibility of the carbon black in low-viscosity polymerizable monomers can be further improved.

It is sufficient for the titanate coupling agent (A) described above to have any one of the amino group, hydroxyl group, or phosphate ester group in its molecule, but it is sufficient to have a plurality (or two or more types) of these functional groups. ), and if necessary, two or more types of titanate coupling agents (having the same type or different types of functional groups) may be used in combination.

In the present invention, for the titanate coupling agent (A) having an amino group, a compound (B
) It is preferable to use a compound having a hydroxyl group, a compound having a carboxyl group, a compound having an acid anhydride group, or a compound having an isocyanate group.

In addition, for the titanate coupling agent (A) having a phosphate ester group or a hydroxyl group, the compound (B
) It is preferable to use a compound having an amino group, a compound having an epoxy group, or a compound having an isocyanate group.

The treatment with the titanate coupling agent (A) and the compound (B) in the present invention is preferably carried out, for example, by the method described below, but is not limited to the method described below.

(1) In a solvent, carbon black is first treated with a titanate coupling agent (A) as described above, and then a compound (
A method of adding B) and heat treatment.

(2) A method in which a titanate coupling agent (A) and a compound (B) that reacts with the functional group of the coupling agent are simultaneously added to carbon black in a solvent and heat-treated.

(3) In a polymerizable monomer, carbon black is first treated with a titanate coupling agent (A) as described above, and then a compound (B) that reacts with the functional group of the coupling agent is added. Method.

(4) A method in which carbon black is treated by simultaneously adding a titanate coupling agent (A) and a compound (B) that reacts with the functional group of the coupling agent in a polymerizable monomer.

Regarding dispersion of carbon black in these methods, it is preferable to use a dispersing machine such as a burr mill or attritor.

The compound (B) used in these treatment methods is preferably used in an amount of 1 part to 50 parts (more preferably 1 part to 25 parts) based on 100 parts of carbon black. If the amount of this compound (8) used is less than 1 part, the effect of improving the dispersibility of carbon black by such treatment will be small, and if it exceeds 50 parts, the viscosity will be high when dispersing the carbon black in the monomer composition. This is not desirable because it becomes too much.

The compound (B) used in the present invention is a functional group that can react with at least one of the amino group, hydroxyl group, or phosphoric acid ester group of the titanate coupling agent (A), and is a hydroxyl group, a carboxyl group, or an acid ester group. A compound having at least one functional group selected from an anhydride group, an isocyanate group, an amino group, or an epoxy group is used. As such a compound (B), either a low-molecular compound or a high-molecular compound (having a number average molecular weight of preferably 1000 or more, more preferably 2000 or more) can be used.

Specific examples of the compound (B) having each functional group will be described below.

(1) Compounds having hydroxyl groups, such as lauryl alcohol, myristyl amecol,
Higher alcohols (preferably C3 to C3°) such as stearyl alcohol; phosphoric acid esters (preferably CII
to CIO); polymers having human fxyl groups such as hydroxyethyl methacrylate-styrene copolymer; and the like are preferably used.

More specifically, the above-mentioned phosphoric acid esters include, for example, monododecyl phosphate, didodecyl phosphate,
sesquidodecyl phosphate, sesquipropyl phosphate, sesquioctyl phosphate, sesquioleyl phosphate, monohexyl phosphate, didodecyl phosphate, monooleyl phosphate, sesquidodecyl polyoxyethylene (3) phosphate, ° sesquidodecyl polyoxyethylene (9) phosphate, Monododecylpolyoxyethylene (5) phosphate, monooctadecylpolyoxyethylene (5) phosphate, sesquidodecylpolyoxypropylene (9) phosphate, monooctadecenylpolyoxypropylene (8) phosphate, and the like are preferably used.

(2) Compounds with carboxyl groups, such as higher fatty acids such as stearic acid and myristic acid (
Preferably, compounds having a carboxyl group such as Cs (Cs); polyester, styrene-methacrylic acid copolymer; etc. are preferably used.

(3) Compounds having acid anhydride groups, such as unsaturated dibasic acid anhydride-vinyl monomer copolymers such as styrene-maleic anhydride copolymers and copolymers of maleic anhydride and α-olefin; dodecenyl Acid anhydrides of higher fatty acids (preferably C2 to C6) such as succinic anhydride are preferably used.

(4) Compounds having isocyanate groups For example, aromatic diisocyanate compounds such as tolylene diisocyanate, nate, diphenylmethane diisocyanate; hydrocarbon chains such as hexamethylene diisocyanate (preferably C2-
C5O) aliphatic diisocyanate compounds and the like are preferably used.

(5) Compounds having an amino group General 2 R'NH2, R'-NH-R', or each preferably represents an alkyl group of 01 to C2°), a primary amine, a secondary amine, or a tertiary amine; Polymers having dialkylamino groups or monoalkylamino groups such as styrene-dimethylaminoethyl methacrylate copolymer; and the like are preferably used.

(6) Compounds having epoxy groups Examples include styrene-glycidyl (meth)acrylate copolymers.

It is sufficient for the above-mentioned compound (B) to have any one of the above-mentioned hydroxyl group, carboxyl group, acid anhydride group, isocyanate group, amino group, or epoxy group, but it is sufficient if a plurality of these functional groups ( Alternatively, two or more of the above compounds (
B) (having the same or different types of functional groups)
may be used in combination.

In the present invention, examples of the carbon black used include carbon black manufactured by Cabot in the United States, Sterling (S
terling) R, Regal 33
0R, Regal 660R, Sogal 400R, Mogul (
Mogu 1) L, Monarch 1
000, etc.; Carbon black manufactured by Columbia Carbon, Raven (R
aven) 7000, Raven 3500, Raven 1
200, Raben 1250, Raben 1255, Raben 450, and Sieben 8000.

The amount of carbon black used is 1 to 30 parts, preferably 5 to 20 parts, based on 100 parts of the polymerizable monomer.

The carbon black to be contained in the monomer composition of the present invention has been explained above, but in the present invention,
If necessary (within the scope not contrary to the purpose of the present invention), other colorants (for example, conventionally known dyes and pigments, which are used to include untreated carbon black) may be included in the monomer composition. The content of this "other coloring agent" in the monomer composition is 100 parts or less (and 50 parts or less) per 100 parts of the treated carbon black used in the present invention.
It is preferable that

Next, materials constituting the monomer composition together with the carbon black treated with the titanate coupling agent as described above will be explained.

Examples of the polymerizable monomer used in the present invention include monomers such as CH2=.

That is, 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-tar
t-butylstyrene, p-n-hexylstyrene, P
-n-octylstyrene, P-n-nonylstyrene%
Styrene and its derivatives such as P-n-decylstyrene and P-n-dodecylstyrene; ethylene, unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene; vinyl chloride, vinylidene chloride,
Vinyl halides such as vinyl bromide and vinyl fluoride;
Vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-methacrylate
α-Methylene fatty acid monocarboxylic acids such as butyl, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, etc. Esters; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate,
Dodecyl acrylate, 2-ethylhexyl acrylate,
stearyl acrylate, 2-chloroethyl acrylate,
Acrylic acid esters such as phenyl acrylate; maleic acid, maleic acid hafester; 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-vinyl compounds such as N-vinylpyrrole, N-vinylcarbazole, N-vinylindole, and N-vinylpyrrolidone; vinylnaphthalenes; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, acrylamide, etc. alone or Use a mixture of two or more types.

Among the above-mentioned monomers, it is preferable to use styrene or a styrene derivative alone or in combination with other monomers as a polymerizable monomer in order to improve the development characteristics and durability of the toner.

! # The polymer composition has fixing properties in hot pressure roller fixing,
In order to improve offset resistance, it is preferable to add a low softening point compound having mold release properties such as waxes such as paraffin wax, and low molecular weight polyolefins such as low molecular weight polyethylene and low molecular weight polypropylene. The amount of the low softening point compound added is determined by the polymerizability J
1 to 300 parts (even 4 to 1 part) per 100 parts of 1L-mer
00 parts).

Examples of low softening point compounds include paraffin, wax, low molecular weight polyolefin, modified wax having an aromatic group,
Examples include hydrocarbon compounds having an alicyclic group, natural waxes, long-chain carboxylic acids having a long-chain hydrocarbon chain having 12 or more carbon atoms (CH3 (cH2γIL or (CH21□2 or more aliphatic carbon chains)), esters thereof, etc. A mixture of different low softening point compounds may be used.

Examples of such low softening point compounds include paraffin wax (manufactured by Nippon Oil), paraffin wax (manufactured by Nippon Kumisen), microwax (manufactured by Nippon Kumisen), microcrystalline wax (manufactured by Nippon Kumisen), and hard paraffin. Wax (manufactured by Nippon Kumisen), PE-130 (manufactured by Hoechst)
: Mitsui Hiwax ll0P, Mitsui Hiwax 220
P, Mitsui Hiwax 660P, Mitsui Hiwax 21
0P, Mitsui Hiwax 320P, Mitsui Hiwax 4
10 P, Mitsui Hiwax 420P, Hilets T-
100X, Highlets T-200X.

Highlets T-300X, Vetrogin 80, Vetrogin 100, Vetrogin 1201 Tactic Ace A-100,
Tac Ace F-100, Tac Ace B-60, modified wax JC-1141, modified wax JC-2130
, modified wax JC-4020, modified wax JC-1
142, modified wax JC-5020 (manufactured by Mitsui Petrochemicals): Examples include beeswax, carnauba wax, and montan wax.

In order to produce a crosslinked polymer, the following crosslinking agent may be present in the monomer composition and suspension polymerization may be carried out. especially,
When a polymer, copolymer or cyclized rubber is not added to the monomer composition, it is preferable to add a crosslinking agent.

Examples of the crosslinking agent include divinylbenzene, divinylnaphthalene, polyethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, 1.3-butylene glycol dimethacrylate, 1.6-hexane gelicold dimethacrylate, and neopentyl glycol dimethacrylate. methacrylate,
Diethylene glycol diacrylate, polypropylene glycol dimethacrylate, 2.2'-bis(4-methacryloxyjethoxyphenyl)propane, 2.2'
- General crosslinking agents such as bis(4-acryloxyjethoxyphenyl)propane, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, tetramethylolmethanetetraacrylate, dibromneopentyl glycol dimethacrylate, diallyl phthalate, etc. It can be used.

If the amount of these crosslinking agents used is too large, the toner will be difficult to melt with heat, resulting in poor heat fixing properties or heat pressure fixing properties. Also, if the amount of crosslinking agent used is too small, properties such as blocking resistance and durability necessary for toner will deteriorate, and during hot roll fixing, some of the toner will not completely adhere to the paper and will adhere to the roller surface. , it becomes difficult to prevent the offset phenomenon of transfer to the next paper. Therefore, the amount of these crosslinking agents used is o per 100 parts of polymerizable monomer.
, oot to 15 parts (more preferably 0.1 to 10 parts) is preferably used.

Next, the polymerization initiator used for polymerizing the monomer composition made of the above-mentioned materials will be described.

According to the findings of the present inventors, when a water-soluble polymerization initiator is used, the moisture resistance of the resulting polymerized toner decreases, and the development characteristics and blocking resistance at high temperatures deteriorate. In order to produce a polymerized toner with excellent properties, it is preferable to use a substantially water-insoluble polymerization initiator.

Here, in the present invention, a substantially water-insoluble polymerization initiator has a solubility of 1 g or less per 100 g of water at room temperature, preferably 0.5 g or less per 100 g of water. , particularly preferably 0.0 g per 100 g of water.
It has a low solubility of 2g or less.

When the polymerization initiator has a solubility of more than 1 g per 100 g of water, decomposition products of the polymerization initiator remaining on the surface of the polymerized toner particles after completion of polymerization deteriorate the moisture resistance of the polymerized toner, which is not preferable.

Further, the polymerization initiator used in the present invention is preferably soluble in the polymerizable monomer, and the amount ranges from the amount usually used (for example, 1 to 10 parts of the polymerization initiator per 100 parts of the polymerizable monomer). ) preferably has solubility characteristics that allow it to dissolve well in the polymerizable LL polymer.

As such a polymerization initiator, 2,2'-azobis-
(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1°1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2, Azo or diazo polymerization initiators such as 4-dimethylvaleronitrile and other azobisisobutyronitrile (AIBN); benzoyl peroxide, methyl ethyl ketone peroxide, isopropyl peroxy carbonate, cumene hydroperoxide, 2.4- Peroxide-based polymerization initiators such as dichloryl benzoyl peroxide and lauroyl peroxide are exemplified.

In particular, it is preferable to use an azobis-based polymerization initiator, which is a neutral initiator, since it is less affected by carbon black.

In the production method of the present invention, it is also preferable to use a mixture of two or more types of polymerization initiators for the purpose of adjusting the molecular weight and molecular weight distribution of the polymer, or for the purpose of adjusting the reaction time.

The amount of the polymerization initiator used is usually 0.1 to 20 parts, preferably 1 to 10 parts, based on 100 parts of the polymerizable 1-ffi product. If the amount of the polymerization initiator is less than 0.1 part, it is difficult to uniformly disperse or apply a sufficient amount of the polymerization initiator to each monomer composition particle. If it exceeds this, the molecular weight of the polymerization product will decrease and the tendency for the polymerization reaction to occur non-uniformly will increase.

In the present invention, the suspension polymerization reaction is usually carried out at a polymerization temperature of 50
The upper temperature limit is set in consideration of the decomposition rate of the polymerization initiator. If the set polymerization temperature is too high, the polymerization initiator will be rapidly decomposed, which is not preferable.

After confirming that the monomer composition particles formed in the granulation process have a predetermined particle size, the polymerization may proceed by keeping the liquid temperature as it is, or by adding an aqueous medium containing the particles. The polymerization reaction is allowed to proceed by adjusting the temperature of the dispersion medium (for example, 50 to 70°C).

Furthermore, when an additive consisting of a polar polymer, a polar copolymer, or a cyclized rubber having a polar group that dissolves in the polymerizable monomer is added to the monomer composition, the polymerizable monomer is polymerized. , a polymerized toner having favorable properties can be obtained.

The polar polymer, polar copolymer or cyclized rubber may be used in an amount of 0.5 to 50 parts, more preferably 1 to 50 parts, based on 100 parts of the polymerizable monomer.
It is recommended to add 40 parts. If the amount of the polar polymer, etc. is less than 0.5 parts, it is difficult to form a sufficient quasi-capsule structure with the polymerizable monomer as described below, and if the amount of the polymer, etc. exceeds 50 parts, the amount of the polymerizable monomer If the amount is insufficient, there is a strong tendency for the properties as a polymerized toner to deteriorate.

A polymerizable monomer composition to which a polar polymer, a polar copolymer, or a cyclized rubber is added is added to the aqueous phase of an aqueous medium in which the polar polymer, etc. and an oppositely charged fine powder dispersion stabilizer are dispersed. Preferably, the cationic or anionic polymer, cationic or anionic copolymer, or anionic cyclized rubber contained in the polymerizable monomer composition is suspended and polymerized in an aqueous medium. The oppositely charged anionic or cationic fine powder dispersion stabilizer dispersed therein is electrostatically attracted to the surface of the toner particles, and by covering the particle surface with the fine powder stabilizer, the particles are bonded together. It prevents and stabilizes. In addition, since the added polar polymer, polar copolymer, or cyclized rubber gathers on the surface layer of the particles that will become the toner, the polar polymer etc. forms a kind of shell-like form, and the resulting particles are It comes to have a pseudo capsule structure. The relatively high molecular weight polar polymer, polar copolymer or cyclized rubber gathered on the surface layer of the particles gives the toner particles excellent properties such as blocking resistance, developability, charge controllability, and abrasion resistance. Grant.

Some of the polar polymers (hereinafter used to include polar copolymers and cyclized rubbers) that can be used in the present invention are illustrated below. Note that polar polymers having a weight average molecular weight of 5.000 to soo, ooo as measured by GPC are preferably used because they dissolve well in the polymerizable monomer and have durability.

(1) Examples of cationic polymers include polymers of nitrogen-containing monomers such as dimethylaminoethyl methacrylate and diethylaminoethyl acrylate, copolymers of styrene and the nitrogen-containing monomers, styrene, and unsaturated carboxylic acids. There are copolymers of esters and the nitrogen-containing monomer.

(2) Anionic polymers include nitrile polymers such as acrylonitrile, halogen-containing monomers such as vinyl chloride, unsaturated carboxylic acids such as acrylic acid, unsaturated dibasic acids, and unsaturated dibasic acids. an anhydride polymer or copolymer of
Alternatively, there are copolymers of styrene and these monomers.

Polyesters and cyclized rubbers can also be used as anionic polymers.

On the other hand, as the dispersion stabilizer, either a wood-philic organic dispersant or a fine powder dispersion stabilizer can be used, but from the viewpoint of improving the moisture resistance of the obtained toner, a fine powder dispersion stabilizer is preferable. used.

Examples of the wood-philic organic dispersant include polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, polyacrylic acid and salts thereof, starch, gum alginate, zein, casein, etc. It will be done.

As the fine powder dispersion stabilizer, a water-soluble inorganic fine powder is preferably used, which has the ability to stabilize the dispersion of monomer composition particles in a liquid medium such as an aqueous medium. The amount of the dispersant added to the aqueous medium is preferably 0.1 to 20 parts, more preferably 1 to 15 parts, based on 100 parts of the monomer composition.

As an anionic fine powder dispersion stabilizer, Aerosil #2
00. #300 (manufactured by Nippon Aerosil Co., Ltd.) Nib Seal E
-22OA (made by Nippon Silica), Fine Seal T-3
Colloidal silica such as No. 2 (Tokuyama Soda Group) can be mentioned.

Examples of the cationic fine powder dispersion stabilizer include aluminum oxide, magnesium oxide, and hydrophilic positively charged silica fine powder such as aminoalkyl-modified colloidal silica treated with a coupling agent.

In the method for producing the toner of the present invention, it is preferable to use a dispersion stabilizer, but the use is not limited to the use of a dispersion stabilizer that has a counterloading property with the polar polymer in the liquid medium.

In addition, in combination with the above-mentioned fine powder dispersion stabilizer, suitable stabilizers such as polyvinyl alcohol, gelatin, methylcellulose, methylhydropropylcellulose, ethylcellulose, sodium salt of carboxymethylcellulose, polyacrylic acid and their salts, starch, etc. ,
1 fl or a mixture of two or more of gum alginate, zein, casein, tricalcium phosphate, talc, palicum sulfate, bentonite, aluminum hydroxide, ferric hydroxide, titanium hydroxide, etc., in an aqueous medium. It may be used in a range that does not adversely affect the method for producing the toner of the present invention.

Furthermore, for uniform dispersion of the inorganic dispersion stabilizer, a surfactant may be used within a range that does not adversely affect the production method of the present invention, and this promotes the desired effect of dispersion stabilization. Specific examples include sodium dodecylbenzene sulfonate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium allyl-alkyl-polyether sulfonate, sodium oleate, sodium laurate, and caprin. sodium acid, sodium caprylate,
Sodium caproate, potassium stearate, calcium oleate, 3.3-disulfonodiphenylurea-
4,4-diazo-bis-amino-8-naphthol-6-
Sodium sulfonate, ortho-carboxybenzene
Azo-dimethylaniline, 2,2,5,5-tetramethyl-triphenylmethane-4,4-diazo-bis-β-
Naphthol-sodium disulfonate, and others can be mentioned. However, it should be noted that when a hydrophilic organic stabilizer or surfactant is used, the moisture resistance of the polymerized toner tends to decrease.

In order to improve granulation properties when the monomer composition contains a polar polymer or cyclized rubber, it is also preferable to add a Brønsted acid such as hydrochloric acid to the aqueous medium, especially a pressed dead acid such as hydrochloric acid. Adding an acid into an aqueous medium
This is advantageous in further enhancing the effects of the anionic polymer, anionic conjugate, or cyclized rubber, and a dispersant (especially a cationic dispersant).

After the polymerization reaction is completed, polymerized toner particles can be obtained by post-treatment using a conventional method. For example, a polymerized toner can be obtained by washing the produced polymer particles to remove the dispersion stabilizer, collecting them by an appropriate method such as filtration, decantation, pre-centrifugation, etc., and drying them.

A charged side oil agent and a fluidity modifier may be added (internally added) to the toner thus obtained, if necessary.
In this case, it is usually sufficient to add these charge control agents, fluidity modifiers, etc. to the monomer composition.The charge control agent and fluidity modifier are mixed with the toner particles after polymerization (external addition). It may also be used separately.

Examples of the charge control agent include a metal complex of an organic compound having a carboxy group or a nitrogen-containing group, a metal-containing dye, and nigrosine. Examples of fluidity modifiers or cleaning aids for the surface of the latent image carrier (photoreceptor) include colloidal silica and fatty acid metal salts. In addition, fillers such as calcium carbonate and finely divided silica may be added to the toner in an amount of 0.5 to 20% by weight for the purpose of increasing the amount. To improve the flowability, a flowability improver such as fine Teflon powder or zinc stearate powder may be added.

The polymerized toner of the present invention can be used in known dry electrostatic image development methods without particular limitations. This polymerized toner can be produced by, for example, two-component development methods such as cascade method, magnetic brush method, microtoning method, two-component AC bias development method; powder cloud method and fur brush method; Non-magnetic component development method in which toner is held and transported to a developing section and subjected to development; Applicable to electric field curtain development method in which toner is transported to a developing section and subjected to development by an electric field curtain method. .

As described above, according to the present invention, there is provided a polymerized toner obtained by suspension polymerizing a monomer composition containing carbon black whose surface has been treated with a titanate coupling agent. Ru.

The polymerized toner of the present invention exhibits uniform triboelectric charging properties based on the high dispersibility of carbon black in the toner, and can provide stable images with high image density.

The present invention will now be described in more detail based on examples.

Mix for 120 minutes at 30°C! L-mer composition (6
A viscosity of 300 cps at 0°C was prepared.

Next, Aeroseal #200 (Japan Aeroseals) 5g
Add the monomer composition prepared above to a 2-liter stainless steel container containing 6.00 g of distilled water and 6.00 g of distilled water.
℃, using a TK homo mixer (Special Machinery and Industrial Vegetables)
Granulation was carried out at 0,000 rpm for 30 minutes, and then the #L polymer composition was polymerized at 60° C. for 10 hours using a paddle stirring blade.

After cooling and dehydrating the polymerization product obtained above, the product is washed with a sodium hydroxide solution, dehydrated, and dried.
A polymerized toner was obtained.

When the particle size of the obtained toner was measured using a Coulter counter (aperture 100 μlll+), the volume average particle size of the toner was 7.5 μm.

When this toner was observed under an optical microscope (200 times magnification), each particle of the toner had an almost completely black spherical shape, and no uneven distribution of carbon black was observed within the toner particles.

Furthermore, using this toner, Canon copier NP-35
When an image formation test was conducted using No. 25, an image with good density and image quality was obtained.

Example 2 Styrene-dimethylaminoethyl methacrylate:! +
- the polymer was dissolved;

Next, a titanate coupling agent Blenact KR-44 (manufactured by Ajinomoto Co., Ltd.) o was added to the above mixture.

After adding 36 g of carbon black (Sterling R manufactured by Cavonto) and 1.2 g of stearic acid, the mixture was kneaded for 120 minutes at 30° C. using an attritor. Thereafter, the mixture was heated to 80° C. and treated with stirring for 2 hours to perform surface treatment with carbon black.

After that, the temperature of the above mixture was adjusted to 60°C, and 2.2'
1 g of -azobisisobutyronitrile and 2 g of 2,2'-azobis-(2,4-dimethylvaleronitrile) were added to prepare a polymerizable monomer composition.

A toner was obtained in the same manner as in Example 1, except that the monomer composition obtained as described above was used. The volume average particle diameter of this toner was 7.0 μm.

When this toner was observed under an optical microscope, no uneven distribution of carbon black in the toner particles was observed. Furthermore,
When an image formation test was conducted using this toner in the same manner as in Example 1, an image with good density and image quality was obtained.

Next, 100 parts by weight of amino-modified silica (Aerosil #200 manufactured by Nippon Aerosil) was mixed with 5 parts by weight of aminopropyltriethoxysilane. 5g (reacted by weight parts), 600g of distilled water, and 1/IO
Capacity 2 containing 20g of N hydrochloric acid. The monomer composition prepared above was added to a stainless steel container, and the mixture was heated at 60°C.
10. Using TK Hoso mixer (Special Machinery and Industrial Vegetables). O
After granulation by stirring at OOrpm for 30 minutes, the -QLffi body composition was polymerized at 60° C. for 10 hours using a paddle stirring blade.

The polymerized product obtained above was cooled and dehydrated, then washed with a sodium hydroxide solution, dehydrated, and dried to obtain a polymerized toner.

When the particle size of the obtained toner was measured using a Coulter counter (aperture 100 μm), the volume average particle size of the toner was 8.0 μm. Further, when this toner was observed under an optical microscope, no uneven distribution of carbon black in the toner particles was observed.

Comparative Example A monomer composition was prepared in the same manner as in Example 1, except that BrenAct KR-11 in Example 1 was not used.

Thereafter, the mixture was heated to 60°C, granulated in the same manner as in Example 1, and then polymerized.

The volume average diameter of this toner was 10.5 μm, and the particle size distribution was broad.

When this toner was observed under an optical microscope, it was found that carbon black was unevenly distributed in the toner particles.

Further, when this toner was applied to a copying machine NP-3525 and an image formation test was conducted in the same manner as in Example 1, the initial image was good, but as images were continuously formed, deterioration of the image was observed.

Claims (1)

[Scope of Claims] 1. A polymerized toner obtained by suspension polymerizing a monomer composition containing at least a polymerizable monomer and carbon black, wherein the carbon black is a titanate coupling agent. A toner for developing electrostatic images characterized by being carbon black treated with. 2. Electrostatic image development according to claim 1, wherein the carbon black is carbon black treated with a reaction product of the following titanate coupling agent (A) and the following compound (B). toner. (A) A titanate coupling agent having an amino group, a hydroxyl group, or a phosphate ester group as a functional group. (B) A group capable of reacting with at least one of the functional groups of the titanate coupling agent (A), which is selected from a hydroxyl group, a carboxyl group, an acid anhydride group, an isocyanate group, an amino group, or an epoxy group. Compounds with