KR20080056839A - Method for preparing toner having uniform particle size distribution and toner prepared by using the method - Google Patents

Abstract

A method for preparing a toner, a toner prepared by the method, and an image forming method using the toner are provided to simplify a manufacturing process and to lower a manufacturing cost by using no emulsifier and to improve storage and durability. A method for preparing a toner comprises the steps of adding a toner composition comprising a macromonomer containing a hydrophilic group, a hydrophobic group and at least one reactive functional group, a polymerizable monomer, a wax and a colorant to a stirring reactor to prepare a polymer latex particle by polymerization; and controlling shear rate or apparent shear rate constantly in the stirring reactor to coagulate the polymer latex particle, thereby preparing a toner. Preferably 90% or more of the shear velocity distribution formed by the stirring reaction system of the reactor is distributed in the section within 5 times of the average shear rate.

Description

Method for preparing toner having a uniform particle size distribution and toner manufactured using the same {Method for preparing toner having uniform particle size distribution and toner prepared by using the method}

FIG. 1 shows the distribution of shear rates in a reactor by the stirred reaction system used in Example 1. FIG.

2 shows the distribution of shear rates in the reactor by the stirred reaction system used in Comparative Example 1. FIG.

3 shows a comparison of the distribution of apparent shear rates in Example 1 and Comparative Example 1. FIG.

Field of invention

The present invention relates to a toner and a manufacturing method thereof. More specifically, the present invention is prepared by polymerizing a toner composition comprising a macromolecular monomer, a polymerizable monomer, a wax, and a coloring agent having a hydrophilic group and a hydrophobic group and containing at least one reactive functional group in a stirred reactor to prepare polymer latex particles. A method of producing a toner by agglomerating particles and a toner produced accordingly. When the toner is prepared by agglomerating the polymer latex particles, a toner having a uniform particle shape and a particle size distribution may be prepared by maintaining a constant shear rate and an apparent shear rate inside the stirring reactor.

Background of the Invention

In the electrophotographic image forming apparatus, the size and particle size distribution of the toner particles affect the resolution of the final printed image. The more uniform and spherical the particle size distribution of the toner particles is and the smaller the particle size is, the higher the resolution of the final printed image can be realized. Recently, there is a growing interest in manufacturing a toner capable of realizing high resolution according to demands of consumers and industries requiring high resolution images.

In general, a method for producing an electrophotographic developing toner for an image forming apparatus can be roughly divided into a pulverization method and a polymerization method, and the polymerization method can be further divided into a suspension polymerization method and an emulsion polymerization method. Since the pulverization method tends to form colored particles having a relatively large particle size distribution, it is necessary to adjust the pulverized toner particles to have a narrow particle size distribution in order to obtain satisfactory development characteristics.

In addition, the pulverization method applies a kneading / grinding process when preparing toner particles, which is difficult to precisely control the shape, particle size, and particle size distribution of the toner particles. It has the disadvantage that the yield is greatly reduced. In addition, there is a problem that the change and adjustment of the toner design for adjusting the charging and fixing characteristics is limited.

Therefore, in recent years, attention has been paid to polymerized toners capable of easily controlling the shape and particle size of particles and obtaining a toner having a uniform particle size distribution even without a separate classification step even at a small particle size.

As a method of preparing toner by suspension polymerization method, US Patent No. 6,033,822 discloses a polymerized toner of a type including a core made of polymer particles colored in a molecule by suspension polymerization and a shell surrounding the core. However, the toner by the suspension polymerization method is difficult to control its shape, and it is difficult to control the particle size due to the limitation of suspension, and there is a problem that the particle size distribution is wide.

As a method of preparing toner by emulsion polymerization method, U.S. Patent No. 6,120,967 and U.S. Patent No. 5,863,696 first prepare an emulsion of components of a toner having a sub-micron size, that is, a binder resin, a colorant, a release agent, and then a coagulation process. The present invention discloses a method of producing spherical particles by primary agglomeration at about 1 to 3 μm, followed by secondary agglomeration or melting after primary agglomeration. However, the production method has a complicated process of agglomeration and / or melting, which brings a lot of technical difficulties in controlling the particle size and spherical particles.

Particularly, in the method for preparing toner by emulsion polymerization method, it is necessary to precisely control the coagulation process of latex particles and colorant dispersion so that the particle size distribution can be uniformly produced. It is a very demanding situation.

The present inventors continued to solve the above problems of the prior art. As a result, when a toner composition including monomer, wax and colorant is put into a stirred reactor and polymerized toner to prepare toner, a stirred reaction system for maintaining a constant distribution of shear rate and apparent shear rate in the stirred reactor is provided. It has been developed to develop a method for producing a toner having a uniform particle size distribution by greatly reducing the fine and coarse amounts of toner particles.

An object of the present invention is to provide a method for producing a toner having a uniform particle shape and particle size distribution by controlling the distribution of shear rate and apparent shear rate inside a stirred reactor for producing toner to a certain range.

Another object of the present invention is to provide a method for producing a toner with a large amount of fine and coarse.

Still another object of the present invention is to provide a method for producing a toner, which can obtain a toner having a desired particle size in high yield by minimizing large aggregates.

It is still another object of the present invention to provide a method for producing a toner having a simple manufacturing process since no emulsifier is used in the aggregation process.

Still another object of the present invention is to provide a manufacturing method of a toner that can reduce production costs and simplify the cleaning process.

Another object of the present invention is to provide a method for producing a toner, which is very advantageous in terms of the environment, since the amount of waste water can be reduced.

It is still another object of the present invention to provide a toner having excellent physical properties in a high humidity environment.

It is still another object of the present invention to provide a toner that is excellent in triboelectric charge characteristics, dielectric property and storage stability and can realize a high quality image.

Still another object of the present invention is to provide an image forming method which enables high quality low temperature fixing using the toner.

The above and other objects of the present invention can be achieved by the present invention described below.

Summary of the Invention

Toner manufacturing method of the present invention comprises the steps of preparing a polymer latex particles by putting a polymerized toner composition comprising a macromonomer, a polymerizable monomer, a wax and a colorant having a hydrophilic group and a hydrophobic group and at least one reactive functional group in a stirred reactor; It is characterized in that it comprises a step of agglomerating polymer latex particles and producing a toner by constantly controlling the shear rate or the apparent shear rate in the stirring reactor.

The stirring reactor includes a stirring blade and a baffle, wherein the stirring blade is a paddle type, a paudler type or a flat type, and the baffles are installed in the reactor 1 to 4 It features.

In the step of preparing the toner by agglomerating the polymer latex particles, at least 90% of the shear rate distribution formed by the stirring reaction system in the stirring reactor is distributed in a section within 5 times the average shear rate.

In the step of preparing the toner by agglomerating the polymer latex particles, the cumulative shear rate distribution in the high shear rate section exceeding 10 times the average shear rate is less than 3%.

In the step of agglomerating the polymer latex particles, 90% of the apparent shear rate ((ε / υ) ^1/2 ) distribution formed by the stirring reaction system in the stirred reactor is three times the average apparent shear rate. It is characterized in that there is no shear section distributed within the section, the apparent shear rate does not appear.

The toner prepared by the above method has a particle size of 0.5 to 20 탆.

The toner produced by the above method has a D50 / D16 of 1.4 or less and a D84 / D50 of 1.4 or less.

Hereinafter, the present invention will be described in detail.

Detailed Description of the Invention

The toner manufacturing method of the present invention comprises polymerizing a toner composition comprising a macromonomer, a polymerizable monomer, a wax and a coloring agent having a hydrophilic group and a hydrophobic group and containing at least one reactive functional group in a stirred reactor to prepare polymer latex particles; Aggregating the polymer latex particles.

In the step of flocculating the polymer latex particles, the shear rate and the apparent shear rate inside the reactor formed by the stirring reaction system must be kept constant. At this time, it is possible to control the aggregation rate by adjusting the pH and ionic strength. In addition, the size and shape of the toner may be adjusted by adjusting reaction conditions such as temperature, heating time, and stirring speed.

Most of the conditions mentioned above are items that can be managed by fixing them to a given value without causing significant fluctuations. However, the flow and mixing inside the reactor can vary greatly depending on the design of the stirred reaction system.

Stirring speed is only one phenomenon seen in a given reactor design, and in practice it should be possible to control shear forces and flow, mixing, etc. within the reactor depending on the shape and dimensions of the stator blades, reactor capacity, and the presence or absence of baffles. Therefore, it is important to define the hydrodynamic conditions in various design reactors as technical items and to examine their characteristics. In the present invention, by controlling the shear rate and the apparent shear rate to a certain level, toner particles by aggregation are uniformly controlled.

The average shear rate is important for controlling the particle size of the particles by the coagulation process, but also the distribution of the shear rate is very important for the uniformity of the particle size distribution by the uniformity of the coagulation. Therefore, in the present invention, in the process of agglomeration of latex particles by emulsion polymerization, a condition in which the shear rate is relatively narrow is distributed, thereby inducing agglomeration by the collision of latex particles relatively uniformly, thereby producing toner particles having a narrow particle size distribution. It is characterized by.

To this end, the present invention is characterized in that more than 90% of the shear rate distribution formed by the stirring reaction system of the reactor in the flocculation step of the polymer latex is distributed in a section within 5 times the average shear rate.

The wider the distribution of the shear rate, the wider the particle size distribution becomes due to the difference in the cohesion between the smaller shear rate and the larger shear rate. Therefore, in the present invention, by distributing more than 90% of the shear rate distribution in the section within 5 times the average shear rate to have a relatively uniform shear force in the entire portion of the reactor. More preferably, 95% or more of the shear rate distribution is distributed in a section within 5 times the average shear rate.

In addition, the present invention is characterized in that the cumulative shear rate distribution is less than 3% in an extremely high shear rate section exceeding 10 times the average shear rate. If the shear rate is very high, the content of large particle size becomes considerably high due to excessive collision, and in a serious case, very large aggregates of hundreds to hundreds of micrometers or more are easily generated. The coagulum thus generated continues to grow during the reaction, resulting in the adverse effect of greatly reducing the yield of toner particles of the desired particle size. Therefore, it is very important to design the stirred reaction system so that the section with extremely high shear rate does not appear inside the reactor.

Nakaoka et al. Introduced the population balance equation shown in Equation (1) to change the particle size and concentration during the particle aggregation process in a paper published in the journal ISIJ International.

(1)

(One)

Where n _k is the particle number density (1 / m 3), δ is the delta function of Kronecker, and N _ij is the collision frequency between i and j particles, respectively. And again, N _ij can be summarized by the following equation (2).

(2)

Where α is the cohesion coefficient, a is the particle radius, ε is the energy dissipation rate, and υ is the kinematic viscosity.

In more detail, ε is the power per unit weight and υ is the dynamic viscosity expressed as (density / viscosity). In the above equation, (ε / υ) ^{1/2, which} is an important factor for determining the collision frequency between particles, is defined as an 'apparent shear rate' as an item comparing local shear rates. As a result, the greater the apparent shear rate, the greater the frequency of collision between the particles and the particles grow by aggregation.

In the present invention, in order to more clearly explain the phenomenon of aggregation in the liquid phase, the above-mentioned apparent shear rate is introduced. In order to obtain a uniform particle size distribution as in the present invention, at least 90% of the apparent shear rate ((ε / υ) ^1/2 ) distribution formed by the stirring reaction system is distributed in a section within three times the average apparent shear rate. There should be no shear zones where no apparent shear rate occurs.

When the apparent shear rate cumulative distribution is 90% or more, the apparent shear rate appears in a region exceeding three times the average apparent shear rate, which means that the distribution of the shear rate is very wide. As mentioned above, when the distribution of shear velocity is wide, it is inevitable that particles with a large difference in aggregate growth due to the difference in the frequency of collisions are obtained.

In addition, the presence of an shearless section in which no apparent shear rate is present means that effective mixing does not occur in the reactor, thus causing a problem in that a large amount of fine particles that do not sufficiently participate in aggregation is present.

In order to achieve the distribution of shear rate and / or apparent shear rate defined in the present invention, it is desirable to design a stirred reaction system such that less vortex and turbulence occurs during stirring.

The stirring system requires a stirring blade and a baffle, and a stirring blade may be typically used as a paddle type, a paudler type, a flat type, and one to four baffles in the reactor. It is appropriate to be installed.

In a reactor without baffles, it is difficult to smoothly induce vertical mixing. In particular, it is difficult to suppress the formation of the vortex flow, so that a flow with a large shear rate gradient is obtained, which makes it difficult to obtain uniform aggregated particles.

The volume average particle diameter of the toner particles produced according to the production method of the present invention is 0.5 to 20 µm, preferably 5 to 10 µm.

The fine amount of the toner particles prepared according to the production method of the present invention may be expressed by dividing D50, which is 50% of the particle size distribution, by D16, which is 16% of the particle size distribution. The D50 / D16 of the toner particles of the present invention is 1.4 or less, preferably 1.3 or less. The smaller this value means that less fine particles are distributed than the average particle diameter.

In addition, the coarse amount of the toner particles prepared according to the production method of the present invention may be represented by dividing D84, which is 84% of the particle size distribution, by D50, which is 50% of the particle size distribution. The D84 / D50 of the toner particles of the present invention is 1.4 or less, preferably 1.3 or less. Similarly, smaller D84 / D50 means less particle size distribution than the average particle size.

In the present invention, polymer latex particles and toners are produced, in particular, by emulsion polymerization. This will be described in detail below.

Preparation of Polymer Latex Particles

The polymer latex particles of the present invention are prepared by putting a toner composition including a macromonomer, a polymerizable monomer, a colorant and a wax into a stirred reactor and polymerizing the same.

While the inside of the reactor is purged with nitrogen gas or the like, a mixture of a medium such as deionized water (or a mixture of water and an organic solvent) and a macromonomer is put into the reactor and heated while stirring.

At this time, an electrolyte such as NaCl or an inorganic salt may be further added to control the ionic strength of the reaction medium. When the temperature inside the reactor reaches an appropriate value, an initiator, preferably a water soluble free radical initiator, is added. One or more polymerizable monomers are then introduced into the reactor in a semi-continuous manner, preferably with a chain transfer agent. At this time, in order to control the reaction rate and the degree of dispersion, the supply of the polymerizable monomer is performed slowly in a starved condition process.

The colorant is dispersed in a mixed solution of macromonomer and deionized water through a disperser. In order not to affect the reaction during the polymerization reaction, a colorant dispersion is added to the reactor and the polymerization reaction is continued. In this case, when the addition time of the colorant dispersion is too early, it may affect the conversion, and when the addition time is too late, the degree or dispersibility of the colorant may not be good.

After the polymerization reaction proceeds, the timing of adding the wax is determined in consideration of the reaction rate and the conversion rate. After the reaction proceeded to some extent, the dispersion liquid in which the wax was dispersed in the mixed liquid of the monomer was introduced into the reactor, and an additional initiator was added to continue the reaction. The polymerization time is determined to be about 6 to 12 hours depending on the temperature and experimental conditions, and is determined by measuring the reaction rate and the conversion rate. In order to control the durability or other physical properties of the toner after the reaction, additional monomers may be added to prepare the polymer latex particles.

The macromonomer used in the present invention is an amphiphilic material having both hydrophilic and hydrophobic groups and has a polymer or oligomeric form having one or more reactive functional groups at its ends.

The hydrophilic group of the macromonomer may be chemically bonded to the particle surface to increase the long term stability of the particles by steric stabilization, and adjust the particle size of the latex according to the amount or molecular weight of the macromonomer introduced. Hydrophobic groups of the thin group macromonomer may be present on the surface of the toner particles to promote the emulsion polymerization reaction. The macromonomer may be combined with the monomer in various forms such as grafted, branched, or crosslinked to form a copolymer.

The weight average molecular weight of the macromonomers according to the invention is 100 to 100,000, preferably 1,000 to 10,000. If the weight average molecular weight of the macromonomer is less than 100, the physical properties of the finished toner may not be improved or may serve as a stabilizer. Moreover, when the weight average molecular weight exceeds 100,000, it is not preferable because reaction conversion may become low.

Examples of the macromonomers include polyethylene glycol (PEG) -methacrylate, polyethylene glycol (PEG) -ethylether methacrylate, polyethylene glycol (PEG) -dimethacrylate, polyethylene glycol (PEG) -modified urethane , Polyethylene glycol (PEG) -modified polyester, polyacrylamide (PAM), polyethylene glycol (PEG) -hydroxyethyl methacrylate, hexafunctional polyester acrylate, dendritic polyester acrylate, carboxy polyester It is preferably one selected from the group consisting of acrylates, fatty acid modified epoxy acrylates, and polyester methacrylates, but is not necessarily limited thereto.

The content of the macromonomer is preferably 1 to 50 parts by weight based on 100 parts by weight of the total content of the toner composition. If it is less than 1 part by weight based on 100 parts by weight of the total amount of the toner composition, there is a problem in that the dispersion stability of the particles is lowered. If it exceeds 50 parts by weight, it is not preferable because the physical properties of the toner deteriorate.

The amphoteric macromonomers of the present invention can act not only as comonomer but also as stabilizer. Initial reaction of radicals with monomers produces oligomeric radicals and exhibits an in situ stabilizing effect. Thermally degraded initiators generate radicals and react with monomeric units in aqueous solution to form oligomeric radicals and increase hydrophobicity. The hydrophobic nature of such oligomer radicals promotes diffusion into the micelles and promotes reaction with polymerizable monomers, and co-polymerization with macromonomers can proceed.

Due to the hydrophilic nature of the amphoteric macromonomer, the copolymerization reaction can occur more easily near the surface of the toner particles. The hydrophilic portion of the macromonomer located on the particle surface enhances the stability of the toner particles by steric stabilization, and can adjust the size of the particles according to the content or molecular weight of the macromonomer to be introduced. In addition, the functional group reacting on the particle surface can improve the triboelectric properties of the toner.

The polymerizable monomer used in the production of the toner of the present invention may be selected from a vinyl monomer, a polar monomer having a carboxyl group, a monomer having an unsaturated polyester group, and a monomer having a fatty acid group.

Specifically, the polymerizable monomer may be a styrene monomer of styrene, vinyltoluene, or α-methylstyrene; Acrylic acid, methacrylic acid; Methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, dimethylaminoethyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate Derivatives of (meth) acrylic acid of dimethylaminoethyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, and methacrylamide; Ethylenically unsaturated monoolefins of ethylene, propylene, butylene; Vinyl halides of vinyl chloride, vinylidene chloride and vinyl fluoride; Vinyl esters of vinyl acetate and vinyl propionate; Vinyl ethers of vinyl methyl ether and vinyl ethyl ether; Vinyl ketones of vinyl methyl ketone and methyl isopropenyl ketone; It is preferably one or more selected from nitrogen-containing vinyl compounds of 2-vinylpyridine, 4-vinylpyridine, N-vinylpyrrolidone, but is not limited thereto.

The content of the polymerizable monomer is preferably 3 to 50 parts by weight based on 100 parts by weight of the total content of the toner composition. If the amount is less than 3 parts by weight based on 100 parts by weight of the toner composition, the yield is lowered, and if it exceeds 50 parts by weight, the stability is lowered, which is not preferable.

Polymeric latex particles according to the present invention include colorants and waxes. In the case of black and white toner as the colorant, carbon black or aniline black can be used.

The nonmagnetic toner according to the present invention is easy to produce color toner. In the case of the color toner, black of the colorant uses carbon black, and the color further includes one or more selected from yellow, magenta, and cyan colorants.

As the yellow colorant, a condensed nitrogen compound, an isoindolinone compound, an atrakin compound, an azo metal complex or an allyl imide compound is used. Specifically C.I. Pigment Yellow 12, 13, 14, 17, 62, 74, 83, 93, 94, 95, 109, 110, 111, 128, 129, 147, 168, 180 and the like can be used.

As the magenta colorant, a condensed nitrogen compound, anthrakin, quinacridone compound, a base dye late compound, a naphthol compound, a benzo imidazole compound, a thioindigo compound, or a perylene compound is used. Specifically C.I. Pigment Red 2, 3, 5, 6, 7, 23, 48: 2, 48: 3, 48: 4, 57: 1, 81: 1, 122, 144, 146, 166, 169, 177, 184, 185, 202, 206, 220, 221, or 254 may be used.

As the cyan colorant, a copper phthalocyanine compound and a derivative thereof, an anthrakin compound, a basic dye rate compound and the like are used. Specifically C.I. Pigment Blue 1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, 66, or the like may be used.

These colorants may be used alone or in admixture of two or more thereof, and are selected in consideration of color, saturation, lightness, weather resistance, dispersibility in toner, and the like.

The content of the colorant is preferably 0.1 to 20 parts by weight based on 100 parts by weight of the polymerizable monomer. The content of the colorant may be any amount sufficient to color the toner. If the colorant content is less than 0.1 part by weight, the coloring effect is not sufficient, and if it exceeds 20 parts by weight, a sufficient frictional charge amount cannot be obtained because the production cost of the toner is increased, which is not preferable.

The wax used in the manufacture of the present invention may be selected and used to meet the purpose of the final toner composition. For example, polyethylene wax, polypropylene wax, silicone wax, paraffin wax, ester wax, carbaue wax, metallocene wax, and the like are not limited thereto. The melting point of the wax is preferably about 50 to 150 ℃.

The wax component is in physical contact with the toner particles but is not covalently bound to the toner particles. The wax component is fixed at a low fixing temperature on the final image receptor and provides a toner that exhibits excellent final image durability and wear resistance characteristics.

The toner composition according to the present invention may be prepared by further including one or more selected from an initiator, a chain transfer agent, a release agent, and a charge control agent.

The toner composition preferably generates radicals by an initiator, and the radicals react with the polymerizable monomer. The radical may react with the reactive functional groups of the polymerizable monomer and the macromonomer to form a copolymer.

As said radical polymerization initiator, Persulfates, such as potassium persulfate and ammonium persulfate; 4,4-azobis (4-cyanoylacetic acid), dimethyl-2,2'-azobis (2-methylpropionate), 2,2-azobis (2-amidinopropane) dihydrochloride, 2, 2-azobis-2-methyl-N-1,1-bis (hydroxymethyl) -2-hydroxyethylpropioamide, 2,2'-azobis (2,4-dimethylvaleronitrile), 2 Azo compounds such as 2'-azobisisobutyronitrile and 1,1'-azobis (1-cyclohexanecarbonitrile); Methylethylperoxide, di-t-butylperoxide, acetylperoxide, dicumylperoxide, lauroylperoxide, benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, di-isopropylper Peroxides, such as an oxydicarbonate and di-t- butylperoxy isophthalate, etc. can be illustrated. Moreover, the oxidation-reduction initiator which combined these polymerization initiators and a reducing agent is mentioned.

The chain transfer agent refers to a substance that changes the type of chain carrier in a chain reaction. New chains have significantly reduced activity compared to the previous one. Through the chain transfer agent it is possible to reduce the degree of polymerization of the monomer and to initiate a new chain. Through the chain transfer agent it is possible to control the distribution of molecular weight.

Examples of the chain transfer agent include sulfur-containing compounds such as dodecanethiol, thioglycolic acid, thioacetic acid and mercaptoethanol; Phosphorous acid compounds such as phosphorous acid and sodium phosphite; Hypophosphorous acid compounds such as hypophosphorous acid and sodium hypophosphate; And alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butyl alcohol, and the like, but are not limited thereto.

The release agent may be suitably used to protect the photosensitive member and to prevent deterioration of developing characteristics to obtain a high quality image. Release agents according to one embodiment of the invention include high purity solid fatty acid ester-based materials. Specifically, low molecular weight polyolefins, such as low molecular weight polyethylene, low molecular weight polypropylene, low molecular weight polybutylene; Paraffin wax; A polyfunctional ester compound etc. are mentioned, for example. As a mold release agent used by this invention, the polyfunctional ester compound which consists of trifunctional or more than trifunctional alcohol and carboxyl is preferable.

As said trifunctional or more than polyfunctional alcohol, For example, Aliphatic alcohol, such as glycerin, pentaerythritol, pentaglycerol; Alicyclic alcohols such as chloroglycitol, xelitol, and inositol; Aromatic alcohols such as tris (hydroxymethyl) benzene; Sugars such as D-erythroose, L-arabinose, D-mannose, D-galactose, D-fructose, L-lamunoose, saccharose, maltose and lactose; Sugar alcohols such as erythrite, D-trate, L-arabit, adnit, and kissitrite; and the like.

The carboxylic acid may be, for example, acetic acid, butyric acid, capronic acid, enanthic acid, capuryl acid, perargonic acid, capuric acid, undecanoic acid, lauric acid, myristic acid, stearic acid, margaric acid, arachidic acid, cellotinic acid. Aliphatic carboxylic acids such as mericic acid, elikaic acid, bursidic acid, sorbic acid, linoleic acid, linolenic acid, beheric acid, tetrolic acid and chisimenic acid; Alicyclic carboxylic acids such as cyclohexanecarboxylic acid, hexahydroisophthalic acid, hexahydroterephthalic acid, and 3,4,5,6-tetrahydrophthalic acid; Aromatic carboxylic acids, such as benzoic acid, a true acid, a cumic acid, a phthalic acid, an isophthalic acid, a terephthalic acid, a trimesic acid, trimellitic acid, a hemimelitic acid, etc. are mentioned.

The charge control agent is preferably selected from the group consisting of metal-containing salicylic acid compounds such as zinc or aluminum, boron complexes of bis diphenyl glycolic acid, and silicates. More specifically, zinc disalicylic acid, borobis (1,1-diphenyl-1-oxo-acetyl potassium salt) {boro bis (1,1-diphenyl-1-oxo-acetyl potassium salt)}, etc. may be used. have.

Agglomeration of the polymer latex particles to prepare a toner

As described above, the polymer latex particles in which the reaction is completed in the emulsion-free, color-free, and wax-free state can adjust the size and shape of the toner particles through an aggregation process. In the present invention, without using an emulsifier at all, an aggregation process for agglomerating latexes already containing a colorant and a wax is carried out as described above at a temperature of Tg or more. The rate of aggregation can be controlled by adjusting the pH of the reaction medium and the concentration of the electrolyte (or inorganic salt).

The medium which can be used in the flocculation process according to the present invention may be an aqueous solution, an organic solvent, or a mixture thereof.

In the present invention, the agglomeration of the polymer latex particles does not use an emulsifier, a colorant, a wax, or the like, thereby minimizing the washing process in the separation and filtration of the manufactured toner particles. By minimizing the cleaning process, the manufacturing process can be simplified to reduce the manufacturing cost of the toner. In addition, by reducing the amount of waste water discharged is very advantageous in terms of the environment. Moreover, the absence of emulsifiers can eliminate problems such as high humidity sensitivity, low frictional charge, reduced dielectric constant, weak toner flow, and can significantly improve the storage stability of the toner.

Finally, the agglomerated toner is separated and dried, and then externally treated with silica or the like to control the charge amount and the like to complete the final toner.

In the toner manufacturing method of the present invention, the latex containing the colorant and the wax is used to control the concentration of pH, electrolyte, or inorganic salt in the non-emulsifying agent, the non-coloring agent, and the wax-free state to fuse and aggregate at temperatures above Tg. A toner may be manufactured by performing a (coalescence) process. The size and shape of the toner particles are adjusted using temperature, heating time, stirring speed, and the like.

In the initial stage of aggregation, pH may be adjusted or inorganic salts such as NaCl or MgCl ₂ may be added to aggregate latex particles containing colorants and waxes. As the pH is increased by adding alkali, the particle surface changes to negative charge or takes up relatively less positive charge. These particle surfaces are mainly due to the presence of large monomer chains chemically bound to the surface, to sulfate groups of initiators such as potassium persulfate (KPS), and to acid groups used as comonomers.

The method may further include adjusting the ionic strength by adding an electrolyte solution or an inorganic salt in the step of agglomerating the polymer latex particles. In the aggregation process, the size of the particles increases due to ionic strength and collisions between the particles.

According to the present invention, the polymer latex can be aggregated by heating to a temperature of Tg or more. This increases the Gibbs free energy of the latex polymer chain at a temperature above the latex Tg, allowing free movement, resulting in the appearance of toner particles with a smooth surface. It is possible to adjust the shape of the particles depending on the temperature conditions.

The morphological differences of toner particles are due to the interfacial force and rheology of the particles. After the toner particles of the desired size and shape are obtained, the toner particles are cooled to below Tg, filtered and separated to dry the toner particles. The dried toner is externally treated with silica or the like, and the toner for the final laser printer can be manufactured by adjusting the charge amount.

According to another embodiment of the present invention, an image forming method comprising the step of depositing a toner on a surface of a photosensitive member on which an electrostatic latent image is formed to form a visible image and transferring the visible image to a transfer material, wherein Toners of the polymer are prepared by polymerizing a toner composition having a hydrophilic group and a hydrophobic group and containing a macromonomer containing at least one reactive functional group, at least one polymerizable monomer, a colorant, and a wax to prepare polymer latex particles, Agglomeration of the polymer latex particles in a wax state, and then to separate and dry the aggregated toner to provide an image forming method.

The present invention may be better understood by the following examples, which are intended for the purpose of illustrating the invention and are intended to limit or limit the scope of the invention, which is protected by the appended claims. no.

Examples 1-3 and Comparative Example 1

Example 1

Styrene-nbutyl acrylate-containing cyan pigment (15: 3, Cu-Phthalocyanine, DIC) and wax (WE-5) in a 3L reactor with 1221 g of deionized water and a one-step polymerization process Add 738 g of methacrylic acid-polyethylene glycol-ethyl ether methacrylate [(styrene)-(n-butyl acrylate)-(methacrylic acid)-(polyethylene glycol-ethyl ether methacrylate)] copolymer latex and stir at 250 rpm It was. In this case, the stirring blades of the reactor used were two-stage paddle type and two baffles were used. The agglomeration process proceeded by adjusting the pH to 2 and then gradually heating it step by step. At this time, when the toner volume average particle size was increased to about 6 μm, the pH was adjusted to 11 and then heated to 95 ° C. After heating for about 1 hour to form a particle, it was cooled and filtered to obtain toner particles.

The volume average size of the finally obtained toner particles was 6.1 µm, and the D50 / D16 was 1.24 and the D84 / D50 was 1.21. In addition, the content of the large aggregates filtered by the 200 mesh sieve was very small, 0.1%, and the yield of the toner particles was high.

The shear rate distribution in the reactor by the stirring reaction system used in Example 1 is shown in Figure 1, the apparent shear rate distribution is shown in Figure 3.

Example 2

Toner particles were prepared in the same manner as in Example 1, except that the stirring blades were used as a puddler type in the reactor's stirring reaction system.

The volume average size of the finally obtained toner particles was 6.3 µm, 1.19 for D50 / D16, and 1.21 for D84 / D50. In addition, the content of the large aggregates filtered by the 200 mesh sieve was very small, 0.2%, and the yield of the toner particles was high.

Example 3

Toner particles were prepared in the same manner as in Example 1 except that the stirring blades were used as a flat plate type, four baffles were used, and the stirring speed was adjusted to 220 rpm.

The volume average size of the finally obtained toner particles was 6.0 µm, and D50 / D16 was 1.23 and D84 / D50 was 1.16. In addition, the content of the large aggregates filtered by the 200 mesh sieve was very small, 0.1%, and the yield of the toner particles was high.

Comparative Example 1

Toner particles were prepared in the same manner as in Example 1 except that the stirring blades were used as a flat plate type and no baffles were used as the stirring system of the reactor.

The volume average size of the finally obtained toner particles was 6.2 µm, and D50 / D16 was 1.57 and D84 / D50 was 1.43. In addition, the content of the large aggregates filtered by the 200-mesh sieve was very high (22%), and the yield of the toner particles was greatly reduced.

The distribution of shear rate in the reactor by the stirring reaction system used in Comparative Example 1 is shown in FIG. 2, and the distribution of apparent shear rate is shown in FIG. 3.

As shown in FIG. 2, in the comparative example, even if the shear rate is extremely high in the distribution of the shear rate, the cumulative distribution shows a shear rate distribution of less than 90%, and there is a large difference in the gradient of the shear rate for each part in the reactor. It can be seen. Agglomeration in the flow with such a high shear rate of about 10% has caused a problem that a large amount of coagulum occurs as shown in the above results. In addition, as shown in FIG. 3, in the apparent shear rate distribution of Comparative Example 1, the shear-free section is present, indicating that the fine powder content is greatly increased.

The present invention adjusts the distribution of shear rate and apparent shear rate inside the stirred reactor to a certain range to lower the fine and coarse amounts, provide a toner with a uniform particle shape and particle size distribution, and simplify the manufacturing process because no emulsifier is used. It is possible to reduce the production cost, to simplify the cleaning process, and to provide an excellent toner manufacturing method which is very advantageous in terms of environment, storage and durability, and an image forming method using the same. .

Simple modifications and variations of the present invention can be readily used by those skilled in the art, and all such variations or modifications can be considered to be included within the scope of the present invention.

Claims (19)

Preparing a polymer latex particle by putting a toner composition including a macromonomer, a polymerizable monomer, a wax, and a colorant with a hydrophilic group and a hydrophobic group and containing one or more reactive functional groups in a stirred reactor; Agglomerating polymer latex particles and preparing a toner by constantly controlling a shear rate or an apparent shear rate in the stirring reactor; A manufacturing method of a toner, characterized in that consisting of. The method of claim 1, wherein the stirring reactor comprises a stirring blade and a baffle. The method of claim 2, wherein the stirring vane is a paddle type, a paudler type, or a flat plate type, and the baffle is installed in the reactor. . The method of claim 1, wherein at least 90% of the shear rate distribution formed by the stirring reaction system in the reactor in the step of agglomerating the polymer latex particles and preparing the toner is distributed in a section within 5 times the average shear rate. A toner manufacturing method, characterized in that. The method of claim 1, wherein in the step of agglomerating the polymer latex particles and preparing a toner, a cumulative distribution of shear rates in a high shear rate section exceeding 10 times the average shear rate is less than 3%. . The method of claim 1, wherein at least 90% of the apparent shear rate ((ε / υ) ^1/2 ) distribution formed by the stirring reaction system in the reactor in the step of agglomerating the polymer latex particles and preparing the toner is an average apparent A method of manufacturing a toner, characterized in that it is distributed in a section within three times the shear rate and there is no shear section in which the apparent shear rate does not appear. The method of claim 1, wherein the macromonomer is polyethylene glycol (PEG) -methacrylate, polyethylene glycol (PEG) -ethylether methacrylate, polyethylene glycol (PEG) -di methacrylate, polyethylene glycol (PEG) -modified Urethane, polyethylene glycol (PEG) -modified polyester, polyacrylamide (PAM), polyethylene glycol (PEG) -hydroxyethyl methacrylate, hexa-functional polyester acrylate, dendritic polyester acrylate, carboxy poly A process for producing a toner, characterized in that it is selected from the group consisting of ester acrylates, fatty acid modified epoxy acrylates, and polyester methacrylates. The method of claim 1, wherein the macromonomer has a weight average molecular weight of 100 to 100,000. The method of claim 1, wherein the polymerizable monomer is selected from the group consisting of a vinyl monomer, a polar monomer having a carboxyl group, a monomer having an unsaturated polyester group, and a monomer having a fatty acid group. The method of claim 9, wherein the polymerizable monomer is a styrene monomer of styrene, vinyltoluene, α-methylstyrene; Acrylic acid, methacrylic acid; Methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, dimethylaminoethyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate Derivatives of (meth) acrylic acid of dimethylaminoethyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, and methacrylamide; Ethylenically unsaturated monoolefins of ethylene, propylene, butylene; Vinyl halides of vinyl chloride, vinylidene chloride and vinyl fluoride; Vinyl esters of vinyl acetate and vinyl propionate; Vinyl ethers of vinyl methyl ether and vinyl ethyl ether; Vinyl ketones of vinyl methyl ketone and methyl isopropenyl ketone; And at least one selected from nitrogen-containing vinyl compounds of 2-vinylpyridine, 4-vinylpyridine and N-vinylpyrrolidone. The method of claim 1, wherein in the step of flocculating the polymer latex particles, a coagulation rate is controlled by adjusting a pH. The method of claim 1, further comprising adjusting an ionic strength by adding an electrolyte solution or an inorganic salt in the step of agglomerating the polymer latex particles. 13. The method of claim 12, wherein the inorganic salt comprises NaCl or MgCl ₂ . The method of claim 1, wherein the polymer latex particles are agglomerated by heating to a glass transition temperature (Tg) or higher of the latex particles. The method of claim 1, wherein the toner composition further comprises at least one selected from an initiator, a chain transfer agent, a charge control agent, and a release agent. A toner prepared by the method of any one of claims 1 to 15 and having a particle size of 0.5 to 20 탆. A toner prepared by the method of any one of claims 1 to 15, wherein D50 / D16 is 1.4 or less in the particle size distribution of the manufactured toner. A toner prepared by the method of any one of claims 1 to 15, wherein D84 / D50 is 1.4 or less in the particle size distribution of the manufactured toner. An image forming method comprising attaching toner to a surface of a photosensitive member on which an electrostatic latent image is formed to form a visible image, and transferring the visible image to a transfer material, wherein the toner uses the toner of claim 16. Forming method.

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