JPS63155156A - Production of electrostatic charge developing toner - Google Patents

Abstract

PURPOSE:To reduce the amount of a dispersion agent and to improve dispersion stability and polymerization stability at the time of a suspension polymerization by effecting the suspension polymerization of at least one kind of polymerizable monomers in the presence of a slightly water soluble phosphate as a suspension agent, and one or two or more kinds of a specific sulfosuccinic acid diester salt. CONSTITUTION:In case that an antistatic agent and a coloring agent are dispersed in at least one kind of the polymerizable monomer, followed by effecting the suspension polymerization of said monomer in an aqueous medium, the suspension polymerization is effected in the presence of the slightly water soluble phosphate as the suspension agent, and one or two or more kinds of the sulfosuccinic acid diester salt shown by formulas I-IV. In formulas I-IV, R1 is 1-36C a straight chain or a branched chain alkyl group, alkylphenyl group having alkenyl group, etc., R2 is aryl, methacryl or 1-12C alkyl group, A is 2-4C alkylene group, (n) is a positive integer of 0-100, in case that R1 is satd. group, (n) is an integer of 1-100, M is a mono or a divalent cation, (m) is an ionic value or M. Thus, the used amount of the dispersion agent is reduced, and the dispersion stability and the polymerization stability of the titled toner at the time of the polymerization can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a dry toner for developing electrostatic images in electrophotography, electrostatic recording, and electrostatic printing, and a method for producing the same.

[Prior art and problems] A developing method using a dry toner whose main components are a colorant and a resin is as follows: (1) The dry toner is mixed with a carrier whose particle size is larger than the toner, and the toner is electrostatically charged by frictional charging. A two-component developer that develops an electrostatic latent image by applying a charge of opposite polarity to the charge of the image and bringing a developer, which is a mixture of toner and carrier, into contact with the electrostatic latent image (2) A toner containing a magnetic material. There is a one-component developer that develops in contact with or in close proximity to an electrostatic latent image.

Conventionally, in order to obtain these toners, thermoplastic resin was melted, coloring agents such as dyes and pigments, and if necessary magnetic materials, tribostatic charge control agents, anti-offset agents, lubricants, etc. were added and thoroughly mixed. The method used was to cool and solidify the powder, pulverize it, and then classify it to obtain the desired particle size.

However, the methods described above have various drawbacks. First, equipment for many processes is required, such as polymerization equipment for resin production, equipment for kneading, crushers, classifiers, etc., and the number of steps is large and energy consumption is large, which increases costs. It is the cause. The second reason is that it is difficult to obtain a uniform mixture in the kneading process, and the conditions for uniform dispersion are particularly delicate. Thirdly, the pulverization process does not only yield fine powder in the appropriate particle size range to obtain clear, fog-free images; fine and coarse particles are produced as by-products that must be classified and removed. There are drawbacks that lead to increased costs, such as the complexity of the process and poor yield for obtaining the desired particle size range.

Fourthly, the resulting powder has an amorphous shape due to pulverization, and the problems include poor fluidity of the fine powder and fogging of the image caused by fine powder caused by re-pulverization due to stirring during frictional charging. It will be done.

In contrast, Special Publication No. 36-10231, Special Publication No. 47
Publications such as Japanese Patent Publication No. 518305 and Japanese Patent Publication No. 14895/1987 describe methods for producing toners by 'Ai and turbidity polymerization methods. This suspension polymerization method does not require pulverization, the manufacturing process is simplified, and it can be said that the above-mentioned drawbacks have been improved.

The suspension polymerization method is generally a method in which a toner composition containing a colorant etc. in a polymerizable monomer is suspended in an aqueous medium and polymerized. Generally, a dispersion stabilizer is present in the dispersion medium.

To explain specifically, there are two main types of dispersion stabilization methods.
There are two methods, one of which is to dissolve a water-soluble polymeric substance such as polyvinyl alcohol or gelatin in a dispersion medium. According to this method, a sufficient dispersion stabilizing effect can be obtained relatively easily, but the water-soluble polymer substance is strongly adsorbed or grafted onto the particle surface of the polymer composition produced, resulting in so-called encapsulation. After polymerization, it is difficult to completely remove it even after repeated washing with water.

Therefore, the toner obtained by this method has the drawback that it is difficult to obtain the charging characteristics required for the toner due to the electrical conductivity or hygroscopicity of the residual dispersant, and it is difficult to obtain good performance.

The other method is to suspend a poorly water-soluble inorganic compound in a dispersion medium. In this method, by sufficiently performing acid washing after polymerization, almost all poorly water-soluble inorganic compounds can be removed, and the charging characteristics required for the toner can be obtained relatively easily. However, in this method, dispersion stabilization is delicately influenced by monomer composition, polymerization conditions, etc., and dispersion stabilization is difficult with a small amount of poorly water-soluble inorganic compound.

Therefore, in order to make these inorganic compounds work effectively, for example, sodium oleate, sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium alkylnaphthalenesulfonate, sodium salt of β-naphthalenesulfonic acid formalin condensate, etc. Anionic activators are used in combination. Select these suspending agents appropriately, and choose the appropriate one. In addition to water at the seismic intensity,
By stirring, it is possible to obtain a relatively good spherical polymer, but in reality, if waste liquid treatment and adhesion to the pot are taken into account, the amount of inorganic salt is even smaller, and the dispersion and polymerization are stable. Good quality is desirable. Further, the fine particles obtained by this method are usually larger than the average particle size suitable for toner, and have a considerably wide particle size distribution. Therefore, if the fine particles obtained by this method are used as they are as a toner, the developability, transferability, rigidity resistance, etc. will be affected, and therefore some kind of classification means is required at present.

The purpose of the present invention is to reduce the amount of dispersant and improve dispersion stability and polymerization stability during suspension polymerization in a method for obtaining toner by suspension polymerization using poorly water-soluble phosphate as a dispersant. It's about doing.

Another object of the present invention is to ensure that fine particles obtained by suspension polymerization in the presence of a poorly water-soluble phosphate have an average particle size suitable for a toner and to improve the particle size distribution.

[Means for solving problems]

In order to improve the above-mentioned drawbacks, the present inventors have conducted intensive research and found that a polymerizable monomer is used as a dispersion stabilizer in an aqueous medium with i1 water-soluble phosphate and a specific sulfosuccinic acid diester. By carrying out suspension polymerization using salt, it is possible to reduce the amount of dispersant used, improve dispersion and polymerization stability during polymerization, and create a polymer with a narrow particle size distribution that has an average particle size suitable for toner. The present inventors have discovered that the following can be obtained, and have completed the present invention.

That is, in the present invention, after dispersing a charge control agent and a colorant in at least one kind of polymerizable monomer, suspension polymerization is carried out in an aqueous medium, and a slightly water-soluble phosphate is used as a suspending agent. , the following general formula (1), (II), (III) or (IV)
(1) 1' 301Ml/5 CHCOO-(AOOR1 So, ?l blind/1I CHzcOOnAO)yR+ SO:1M+/- CHCOO stem A OhlR+ ■ 503M1/- (In the formula, R is a straight chain with 1 to 36 carbon atoms or a branched alkyl group, an alkenyl group, a cycloalkyl group, a phenyl group, or an alkylphenyl group having an alkyl group having 1 to 24 carbon atoms; R2 is an allyl group, a methallyl group, or an alkylphenyl group having 1 to 24 carbon atoms;
12 alkyl group, A represents an alkylene group having 2 to 4 carbon atoms, n represents a positive number from O to 100, Hakama represents a monovalent or divalent cation, and I represents the ionic valence of the gate. show. )
One or two sulfosuccinic acid diester salts represented by
The present invention relates to a method for producing a toner for developing an electrostatic image, which is characterized by carrying out suspension polymerization in the presence of at least one species.

The toner of the present invention is produced by first mixing and dispersing a colorant such as a carbon blank, a charge control agent, and other necessary toner property improvers in a polymerizable monomer, and using this as an oil phase, a slightly water-soluble phosphoric acid The above oil phase is added to an aqueous phase in which a salt and one or more sulfosuccinic acid diester salts represented by the above general formulas (1) to (IV) are uniformly dissolved, and a homomixer is obtained.
Disperse to 5 to 30 μm using a dispersing means such as a homogenizer. The weight ratio of the oil phase to the aqueous phase is in the range of 1:1 to 1:20, and is set in such a range that coalescence of particles does not occur during polymerization.

The dispersion liquid in which the oil phase is uniformly dispersed in the water phase is transferred to a polymerization reaction tank equipped with a stirring device, a condenser, a thermometer, and a nitrogen inlet tube, and the temperature is raised to the temperature at which the polymerization initiator decomposes (50 to 90 °C). Polymerization is carried out under a nitrogen atmosphere.

After the polymerization is complete, add hydrochloric acid to eliminate the phosphate,
The aqueous phase is removed by filtration, and after washing with water, water is removed by spray drying, vacuum drying, or the like to produce a toner.

In the present invention, examples of the poorly water-soluble phosphate include calcium phosphate, barium phosphate, magnesium phosphate, etc., but calcium phosphate is particularly preferred.

Calcium phosphate as used herein mainly refers to tertiary calcium phosphate (Ca3(PO4)i), which can be synthesized as a precipitate by, for example, a reaction between calcium chloride and tertiary sodium phosphate. In addition, hydroxyapatite (mca
It is also possible to improve the suspension effect by producing it as s(PO4)z .nCa(011)z). Therefore, the calcium phosphate referred to herein is a calcium phosphate salt in a broad sense, including the above-mentioned hydroxyapatite.

Furthermore, the smaller the particles of phosphates such as calcium phosphate, the greater the suspension effect and the better the reproducibility. The poorly water-soluble phosphate used in the present invention has primary particles in the range of 0.01 to 3 μm.

In the present invention, the water-repellent phosphate is
It is used in a range of 0.1 to 30% by weight, preferably in a range of 0.5 to 15% by weight.

In the general formulas (I) to (IV), R8 represents an alkyl group such as 2-ethylhexyl, lauryl, myristyl, and stearyl, an alkenyl group such as oleyl, a cycloalkyl group, a phenyl group, octylphenyl, nonylphenyl, and lauryl. Examples include alkylphenyl groups such as phenyl. Examples of R2 include alkyl groups such as allyl group, methallyl group, methyl, ethyl, propyl, and butyl.

Specifically, the compounds shown below may be mentioned.

CHzCOO(CtlzCHzO)-rr-C+zHz
sCHCOOCHzCIICIlzOCHzCtl□C
l1zI SO,N, 011 CIl□CQOCII□C)ICII□0CHzCH=
C) 12CHCOO-(CHzcIl zohTC+
zll z s■ 5O3N.

CHCOOCII□CHCII□0CHzCII=CH
z(l 5OffN, 0H CIIzCOOCIlzCHCHzOCHzCH=CH
zSO3N.

SO, N11 CIICOOCH2CHCII20CH2CH=CH2
l 5O3N, 011 CH, -Coo 21125" CHCOOCthCHCl1z □ SO,N.

C1hCOOCHzCH=CIl□ C! (COOC+Jzs SO, N.

CHzCOOC+□Ihs CHCOOCtlzCHCHzOCHzCIl=CHz
j SO3N, 0H CIZCooClrZ(JICH20C1(ZCH=C
IIZCHCOOC, □OtS ■ 5O3N.

ChzCOOCJ+q ! cnccoocsn+ amount 5O3N.

C112COOCI88:+7 CHCOOCII□CIICHzOcll zclIP
cHzll 5O3N, 011 These sulfosuccinic acid diester salts are 0.01 to 10% by weight, preferably 0.1% by weight, based on the slightly water-soluble phosphate.
It is used in a range of 5% by weight. Further, two or more of these may be used in combination.

The charge control agent used in the present invention may be either positively chargeable or negatively chargeable, and any known charge control agent may be used in commonly used materials.

For example, if a negatively chargeable charge control agent such as an azo complex dye is used, a negatively chargeable toner can be obtained, and if a positively chargeable agent such as nigrosine is used, a positively chargeable toner can be obtained. It can be used depending on the situation.

The colorant used in the present invention includes various carbon blacks produced by the thermal black method, acetylene blank method, channel black method, furnace black method, lamp black method, etc. in the case of black toner, and copper phthalocyanine in the case of color toner. , monoazo pigment (C
.

1, Pig++ent Red 5. C,1,Pigm
ent Oranlge 36+C,r.

Pigment Red 22) + disazo pigment (C
, 1, Pigment Yellow 83), anthraquinone pigment (C, 1, Pigment Blue 60)
), disazo dye (Solvent Red 19)
, rhodamine dye (Solvent Red 49)
etc.

As the polymerizable monomer used in the present invention, polymerizable monomers having 3 to 25 carbon atoms can be used, such as styrene, p-chlorostyrene, p-methylstyrene, vinyl acetate, vinyl propionate, Vinyl benzoate, methyl acrylate, ethyl acrylate, n-butyl acrylate, 1so-butyl acrylate, dodecyl acrylate, n-octyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate,
1so-butyl methacrylate, diethylaminoethyl methacrylate, t-butylaminomethyl methacrylate, acrylonitrile, 2-vinylpyridine, 4-vinylpyridine and the like can be used alone or in combination.

Furthermore, in the present invention, by adding polyfunctional monomers such as divinylbenzene, ethylene glycol dimethacrylate, trimethylolpropane triacrylate, glycidyl methacrylate, and glycidyl acrylate to the above monomers as a crosslinking mixture, the durability can be further improved. toner can be produced. The content of the polyfunctional monomer is 0.05 to 20% by weight, preferably 0.5 to 5% by weight, based on the heptadium.

As the polymerization initiator, commonly used oil-soluble peroxide-based or azo-based initiators can be used. For example, benzoyl peroxide, lauroyl peroxide, 2,2'-azobisisobutyronitrile, 2'2'-azobis-(2,4-dimethylvaleronitrile), orthochlorobenzoyl peroxide, orthomethoxybenzoyl peroxide. Can be mentioned. These are used in an amount of 0.1 to 10% by weight, preferably 0.5 to 5% by weight, based on the polymerizable monomer.

Further, the toner of the present invention may contain a low molecular weight olefin polymer known as a so-called mold release agent for the purpose of preventing offset, improving fluidity, improving fixing properties, and the like.

It is preferable that this low molecular weight olefin polymer be present during monomer polymerization together with the colorant used in the present invention.

Examples of the low molecular weight olefin polymer used in the toner of the present invention include polyethylene, polypropylene, ethylene vinyl acetate copolymer, chlorinated polyethylene wax, polyamide, polyester, polyurethane, polyvinyl butyral, butadiene rubber, phenolic resin, epoxy resin, and rosin. Examples include modified resins, silicone oils, and silicone waxes.

The amount of the low molecular weight olefin polymer used is 1 to 20 parts by weight, preferably 3 to 15 parts by weight, per 100 parts by weight of the resin component of the toner, and if it is less than 1 part by weight, it may not have a sufficient offset prevention effect. Moreover, if the amount is 20 parts by weight or more, gelation may occur during polymerization, which is not preferable.

To form an image using the toner of the present invention, for example, by electrophotography, use a selenium photoreceptor, or zinc oxide, cadmium sulfide, cadmium selenide, cadmium selenide sulfate,
A photoreceptor in which a photosensitive layer containing an inorganic photoconductive material such as lead oxide or mercury sulfide dispersed in a binder resin is provided on a conductive support, or an organic photoconductive material such as anthracene or polyvinylcarbazole is used. A photoreceptor is used in which a photosensitive layer is provided on an electrically conductive support, and the photosensitive layer is contained in a binder resin if necessary. The surface of the photosensitive layer of such a photoreceptor is covered with a corona discharge using, for example, a corotron or scorotron charger, and then imagewise exposed to light or the like to form an electrostatic charge image. Next, this electrostatic charge image is developed, for example, by a cascade method or a magnetic brush method, with a developer consisting of a mixture of the toner of the present invention and a glass beads or iron powder carrier to form a toner image. This toner image is transferred onto the transfer paper by being pressed against the transfer paper under, for example, corona discharge. The toner image transferred onto the transfer paper is heat-fixed by a hot roll fixing device coated with a fluororesin or silicone rubber having releasable properties.

〔Effect of the invention〕

As explained in detail above, when producing toner for developing electrostatic images by suspension polymerization, in the present invention, a charge control agent and a colorant are dispersed in a polymerizable monomer, and a poorly water-soluble phosphor is dispersed in the polymerizable monomer. By carrying out suspension polymerization in the coexistence of acid salts and specific dispersion stabilizers, the dispersion and polymerization stability can be improved, and as a result, even if the amount of phosphate used is reduced, the amount of aggregates can be reduced. I was able to keep it low. Furthermore, by this method, it was possible to obtain a toner having a suitable average particle size and a suitable particle size distribution.

Therefore, according to the present invention, toner is produced by suspension polymerization! !
! We were able to provide a manufacturing method that takes advantage of the simplicity of manufacturing and provides a toner with excellent developability, transferability, and rigidity resistance.

〔Example〕

Examples of the present invention are shown below, but the present invention is not limited thereto. Note that parts in the examples are parts by weight.

Example 1 Styrene 85 parts, n-butyl acrylate 15 parts, carbon blank (manufactured by Mitsubishi Kasei ■, #44) 6 parts, low molecular weight polyethylene (Mitsui Petrochemical Industries ■, Mitsui Hiwax 210P) 2 parts, charge control agent (manufactured by Odugaya Kagaku ■, Aizen Subiron Black TRH) 1.5 parts of the mixture was dispersed in a ball mill for 10 hours. Add 2 to this dispersion,
After dissolving 1 part of 2°-azobisisobutyronitrile,
3.5 parts of tertiary calcium phosphate with a particle size of 0.5 to 1.3μ, and a sulfosuccinic acid diester salt represented by the following formula (
Latemur S-120PA, Kao side! ! The mixture was added to 350 parts of an aqueous solution containing 0.15 parts of water, and stirred for 3 minutes at 3000 rpm using a TK homo mixer (manufactured by Tokushu Kika Kogyo ■).

CHCOOC1hCHCHzOCHzCH=CHzSo
, N, 01 (This suspension was heated in a separable flask at 75° C. and 8 ℃ under a nitrogen atmosphere at a stirring speed of 100 rpm with an ordinary stirrer.
The polymerization reaction was carried out for a period of time.

After the polymerization was completed, the mixture was passed through a 100-mesh metal mesh, and the amount of aggregates was as low as 0.15% based on the oil phase.

Further, after washing with hydrochloric acid and water, it was dried overnight in a vacuum dryer at 40°C. The particle size and particle size distribution of the obtained toner were measured using a Coulter counter and were found to be appropriate as shown in Table 1.

Carrier iron powder (D, M) is added to 5 parts of this toner.

When 95 parts of CB-100 (manufactured by Sceart) were mixed and the amount of charge was measured using a blow-off charge amount measuring device, it was found that -
It was 16.7 pc/g.

Also, when I took an image with Ricoh FT4060,
A clear image without fogging was obtained. Further, even after copying 10,000 sheets, there was almost no change in the amount of charge, and no fogging was observed, and high-quality images that were the same as the initial image quality were obtained. Further, the transfer efficiency was good with an average of 83 to 87%.

Example 2 Suspension polymerization, hydrochloric acid washing, Washing with water was performed to obtain toner particles.

The amount of aggregates was as low as 0.21% based on the oil phase.

The particle size and particle size distribution of the obtained toner are shown in Table 1.

A developer was prepared using this toner in the same manner as in Example 1,
When the amount of charge was measured, it was -18.5 IC/g.

Furthermore, images were taken using a Ricoh FT4060, and clear images with no fog were obtained. A further printing durability test was carried out up to 30,000 copies, but the image quality was almost the same as the initial image quality, and the amount of charge was also almost unchanged.

Furthermore, the transfer efficiency was as good as 84% on average.

Example 3 In Example 1, a particle size of 0.1 to 0.5 was used as a dispersant.
p hydroxyapatite (3Ca3(PO4) z
・After suspension polymerization in the same manner as in Example 1, except for using 3 parts of Ca(OH)z) and Latemul 5180 (manufactured by Kao Corporation) represented by the following formula %, washing with hydrochloric acid,
Washing with water was performed to obtain toner particles. The amount of aggregates was as low as 0.08% based on the oil phase.

The particle size and particle size distribution of the obtained toner are shown in Table 1.

A developer was prepared using this toner in the same manner as in Example 1,
When the amount of charge was measured, it was -16.2 μC/g.

In addition, we conducted a printing durability test of up to 30,000 sheets using Ricoh FT4060, and the image quality was almost the same as the initial image quality, with no fogging and clearness.

Example 4 In Example 1, a particle size of 0.1 to 0.5 was used as a dispersant.
μ hydroxyapatite (3Ca3(POa) z
After suspension polymerization, washing with hydrochloric acid and water were carried out in the same manner as in Example 1, except that 3 parts of Ca(OH)z 1 and a sulfosuccinic acid diester salt represented by the following formula % were used, followed by washing with hydrochloric acid and water to obtain toner particles. Ta. Aggregates are 0.0% relative to the oil phase.
It was low at 23%.

The particle size and particle size distribution of the obtained toner are shown in Table 1.

Table 1 Comparative Example 1 Example 1 except that Latemul S-120PA was replaced with sodium dodecylbenzenesulfonate.
After suspension polymerization in the same manner as above, washing with hydrochloric acid and water were performed to obtain toner particles. The amount of aggregates was 8.8% based on the oil phase. In addition, as a result of measuring the particle size and particle size distribution with a Coulter counter, the average particle size was 16.5μ, which is larger than the appropriate size for the toner, and 1.4% by volume of particles smaller than 5μ, and 8.5% by volume of particles larger than 25μ. The volume % and distribution were also wide.

Using this toner, a developer was prepared in the same manner as in Example 1, and the amount of charge was measured and found to be -10.3 pc/g.

Furthermore, when images were produced using Ricoh FT4060, there were phenomena in which the images lacked sharpness and the image density was too high. Furthermore, fogging was also observed.

After copying another 1000 sheets, the amount of charge was 7.6μc/
It decreased to g. The transfer efficiency was very poor at 35-45%, and the amount of toner consumed was as high as 90-1 Lol1g/sheet.

Comparative Example 2 Suspension polymerization was carried out in the same manner as in Example 1, except that LaTemul S-120PA was replaced with sodium oleate. However, most of the suspended particles agglomerated and adhered to the stirring blades and reactor walls.

Comparative Example 3 Suspension polymerization was carried out in the same manner as in Example 1, except that Latemul S-120PA was replaced with a sodium salt of β-naphthalenesulfonic acid formalin condensate (Demol N, manufactured by Kao Corporation). The amount of aggregates was 6.5% based on the oil phase.

Furthermore, washing with hydrochloric acid and washing with water were performed to obtain toner particles.

The average particle size was 12 to 13μ, but the particle size distribution was wide, with 2.5% by volume of particles smaller than 5μ and 6.3% by volume of particles larger than 25μ.

Furthermore, a developer was prepared in the same manner as in Example 1, and Ricoh F
When the image was produced using T4060, it was found that the image lacked sharpness and some fogging was observed.

Applicant's agent Kaoru Furutani Procedural amendment (voluntary) October 26, 1986

Claims (1)

[Claims] 1. After dispersing a charge control agent and a colorant in at least one kind of polymerizable monomer, when performing suspension polymerization in an aqueous medium, sparingly water-soluble phosphoric acid is used as a suspending agent. salt and the following general formula (
I ), (II), (III) or (IV) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (III) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(IV) (In the formula, R_1 is a linear or branched alkyl group having 1 to 36 carbon atoms, an alkenyl group, a cycloalkyl group, a phenyl group, or a carbon number 1 to 36. An alkylphenyl group having 24 alkyl groups, R_2 is an allyl group, methallyl group, or an alkyl group having 1 to 12 carbon atoms, A is an alkylene group having 2 to 4 carbon atoms, and n is a positive 0 to 100 group. (M represents a monovalent or divalent cation, and m represents the ionic valence of M.) A method for producing a toner for developing an electrostatic image.