JP2005171062A - Method for preparing latex polymer, and method for producing toner for electrostatic charge image development - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for preparing a latex polymer capable of suppressing occurrence of coarse particles in toners used for a printer and a copying machine forming images by the electrophotographing process and enabling to maintain stable characteristics of the latex polymer, and a method for producing a toner for electrostatic charge image development by using this latex. <P>SOLUTION: This method for preparing the latex polymer comprises (i) a step of producing a polymer by adding a small amount of a monomer emulsion to an aqueous phase and initiating seed polymerization, and (ii) a step of adding monomer emulsion further to the composition produced in the step (i) and conducting emulsion polymerization to produce the latex polymer, where, in both the above steps, deposited matter on the surface to be cleaned in the production apparatus is removed by high pressure water of 100-400 MPa. This method for producing a toner for developing the electrostatic charge image comprises agglomerating latex resin particles and forming agglomerated particles, then heating the agglomerated particles to be fused. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a preparation method for producing a latex by a semi-continuous emulsion polymerization method, and a method for producing a toner for developing an electrostatic image using the latex.

  In this technique, a method is known in which a latex polymer produced by batch-type or semi-continuous emulsion polymerization and a colorant are aggregated to form a toner. For example, Patent Document 1 relates to a semi-continuous emulsion polymerization method in which a latex is prepared after generation of a seed polymer, and more specifically, a production method including the following steps (i) to (iv) is described. .

  (I) a monomer, a chain transfer agent, a disulfonic acid surfactant (s), and a step of emulsifying the monomers including an initiator as necessary; and (ii) the monomer prepared in (i). About 0.5 to about 50% by weight of the emulsion, desirably about 1 to about 25% by weight of the monomer emulsion portion (a), and about 0.5 to about 100% by weight of the total initiator used to prepare the latex polymer; Desirably emulsion-polymerizing a mixture comprising from about 3 to about 100% by weight of a free radical initiator (b) at a temperature of about 35 to about 125 ° C. to prepare a seed particle latex; (iii) formation The seed particles are heated to a temperature of about 35 to about 125 ° C., and about 50 to about 99.5%, preferably about 75 to about 97% by weight of the remaining monomer emulsion of the monomer emulsion prepared in (i) And if necessary Adding from about 0 to about 99.5%, preferably from about 0 to about 97% by weight of free radical initiator of the total initiator used in the preparation of the latex polymer; (iv) contents in the reactor above. The article is held at a temperature of about 35 to about 125 ° C. for an effective time to form a latex polymer, such as about 0.5 to about 8 hours, preferably about 1.5 to about 6 hours, and then allowed to cool. And a process.

  In addition, a preparation method has been proposed in which the latex used for the preparation of toner particles by emulsion aggregation is prepared by adjusting the amount of anionic surfactant added and without using a nonionic surfactant (for example, patents). Reference 2).

  In addition, in an electrostatic latent image developing toner in which at least resin particles and colorant particles are salted out and fused, the resin particles are polymerized in an aqueous medium in which a polymerizable monomer constituting the resin particles is emulsified. It has been proposed to use resin particles polymerized by adding an initiator at an average addition rate of 0.1 wt% to 5 wt% of the total polymerizable monomer per minute (for example, Patent Document 3). In addition, a method of preparing resin particles obtained by adding a total polymerizable monomer to an aqueous solution in which a polymerization initiator is dissolved at the same average addition rate as described above to prepare a polymer particle is proposed (for example, Patent Document 4). .

  The known semi-continuous emulsion polymerization method described above is in a form in which an emulsion is added to a reaction vessel that is a production apparatus and allowed to react as needed, but in general, deposits are generated in the reaction vessel. In continuous production, the growth of deposits is gradually accelerated, and a thick film is formed on the inner wall surface of the reaction tank. As a result, the heat transfer property of the inner wall surface of the reaction tank decreases, Temperature control becomes difficult, and control of polymer properties such as molecular weight and particle size distribution tends to be difficult.

  In addition, if large deposits deposited and generated due to the progress of deposit growth in the reaction tank fall into the reaction tank, it becomes difficult to discharge the contents of the polymerization reaction tank, and the operation is stopped for cleaning. It is also necessary to let

  In order to cope with the shortening of continuous production due to such deposit accumulation, a material that is difficult to adhere is applied to the adherend surface of the inner wall of the polymerization reaction tank, surface treatment is performed, and adhesion is suppressed. In many cases, a film is formed. However, even if these treatments are performed, there is only an effect of delaying initial adhesion, and it cannot be a fundamental solution. Therefore, thorough cleaning that enables continuous operation of the polymerization reaction tank is desired.

  For example, as a cleaning method for a reaction vessel, a blasting method that is also used in a conventional pulverizing toner, a cleaning method using a sublimable solid such as dry ice (for example, Patent Documents 5, 6, and 7), an organic solvent, A method of using and washing manually is common.

  However, although cleaning with sublimable solids and solvents is excellent in detergency, there are problems in environmental impacts such as waste liquid and waste gas treatment, and safety and health for workers.

  Therefore, Patent Document 8 proposes a method using high-pressure soft water of 5 to 100 MPa as a cleaning method that does not use a solvent. However, in this method, the pressure is not sufficient and the cleaning power is poor.

US Pat. No. 5,853,943 JP 2001-247607 A JP 2000-250262 A JP 2000-250263 A Japanese Patent Laid-Open No. 10-319634 JP-A-10-319638 JP 2002-86089 A JP 2002-244344 A

  In any of the above-described cleaning methods, it is difficult to sufficiently remove the deposits in the reaction tank, and as a result, it is difficult to stably and continuously produce a desired latex polymer.

  The present invention has been made in view of the above problems, and provides a method for producing a latex polymer that does not deteriorate the performance of the latex polymer, improves production efficiency, and reduces production costs, and also provides an electrostatic charge image using the latex. The object is to provide a method for producing a developing toner.

  The present invention takes into account that the cause of the above-mentioned problem is mainly due to the washing method of the latex polymer reaction tank, and a method for solving the above-mentioned problem by the following constitution, and an electrostatic charge image using the latex obtained by this method The present invention relates to a method for producing a developing toner.

  (1) In the latex polymer preparation method, after the latex polymer is prepared, each time the latex polymer is discharged from the manufacturing apparatus or after the latex polymer is prepared and discharged several times by the manufacturing apparatus, This is a method for producing a latex polymer, in which deposits on the inner wall surface are removed with high pressure water of 100 to 400 MPa.

  (2) (i) adding a small amount of monomer emulsion to the aqueous phase, starting seed polymerization to produce a polymer, and (ii) adding a monomer emulsion to the composition produced in step (i). A method of preparing a latex polymer by performing emulsion polymerization to remove a deposit on a surface to be cleaned of a manufacturing apparatus used in the method for preparing the latex polymer with high pressure water of 100 to 400 MPa. This is a method for producing a latex polymer.

  (3) Moreover, it is a preparation method of the latex polymer as described in said (1) or (2) whose flow volume of the said high pressure water is 1-100 L / min.

  (4) In the method for producing a toner for developing an electrostatic charge image, wherein the fine particles are aggregated in a dispersion obtained by dispersing at least resin fine particles to form aggregated particles, and then heated to fuse the aggregated particles. This is a method for producing a toner for developing an electrostatic charge image, in which the fine particles are resin fine particles obtained by the method for preparing a latex polymer according to any one of (1) to (3) above.

  (5) The method for producing a toner for developing an electrostatic charge image according to the above (4), wherein the obtained resin particles have an average particle size of 50 to 500 nm.

  According to the present invention, it is possible to stably produce a desired latex polymer by adjusting the pressure and flow rate of high-pressure water washing within an appropriate range in the removal of deposits adhering in a production apparatus for preparing a latex polymer. it can.

[Method for preparing latex polymer]
As a method for preparing the latex polymer of the present invention, for example, a method in which at least a monomer and an initiator are additionally added to an emulsion containing a monomer, a surfactant and water (hereinafter referred to as “monomer emulsion”), a monomer Examples thereof include a method in which different types of monomer emulsions are added simultaneously or with a time difference, and a method in which a monomer emulsion is emulsion-polymerized to form a seed polymer, and then a monomer emulsion is further added.

  In this embodiment, a seed polymer (so-called seed particles) is generated and then a monomer emulsion is further added to prepare a latex polymer (hereinafter referred to as “latex polymer preparation method using a seed polymer”) as an example. Explained.

  The latex polymer preparation method using the seed polymer includes preparation of an aqueous emulsion of monomers. In order to produce an emulsion, a monomer and an anionic surfactant are usually added to water and stirred to form an emulsion. A free radical initiator may or may not be added to this monomer emulsion.

  Once the monomer emulsion is formed, 25 wt% or less of the monomer emulsion (ie, a small amount of monomer emulsion) and the free radical initiator are added to the aqueous phase and mixed to initiate seed polymerization at the desired reaction temperature. The free radical initiator may be added before or after the addition of a small amount of the monomer emulsion, or at the same time.

  After the seed particles are formed, a monomer emulsion is further added to the seed particle-containing composition, and polymerization is continued at a specified temperature for a desired time to complete the polymerization, thereby forming a latex polymer. A free radical initiator may be added during the addition of the monomer emulsion and polymerization.

  In this embodiment, one or more monomers are used to form a latex polymer, and the monomers can be appropriately selected according to the application or characteristics. Specific examples of monomers used in the preparation method of the present embodiment include styrenes such as styrene, parachlorostyrene, and α-methylstyrene that can form styrene resins; acrylic acid that can form vinyl resins. Methyl, ethyl acrylate, acrylate acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-methacrylic acid 2- Esters having a vinyl group such as ethylhexyl; Vinyl nitriles such as acrylonitrile and methacrylonitrile capable of forming vinyl resins; Vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether capable of forming vinyl resins ; Vinyl resin Formable vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone; Olefin such as ethylene, propylene, butadiene, isoprene capable of forming olefin resin; Epoxy resin, polyester resin, polyurethane resin, polyamide resin, cellulose resin And monomers capable of forming non-vinyl condensation resins such as polyether resins. Among the above monomers, monomers capable of forming a vinyl resin are particularly preferable, which is advantageous in that a resin dispersion can be easily prepared by emulsion polymerization or seed polymerization using an ionic surfactant or the like.

  Furthermore, monomers used in the preparation method of the present embodiment are acrylic acid and methacrylic acid esters, styrene, fatty acid vinyl esters, ethylenically unsaturated carboxylic acids, known crosslinking agents, etc. It is not limited to these. Suitable ethylenically unsaturated carboxylic acids are, for example, acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, 2-carboxyethyl acrylate (β-CEA), and the like. Desirably two or more monomers are used. More specifically, monomers including styrene, n-butyl acrylate, and / or β-CEA are desirable.

  The produced latex polymer may or may not be crosslinked. Any suitable crosslinking agent can be used. Examples of suitable crosslinking agents include, but are not limited to, divinylbenzene, divinyltoluene, diacrylates, dimethylacrylates, and the like. The cross-linking agent may be added during the preparation of seed particles and / or during the addition of further monomer emulsions.

  Specific examples of the crosslinking agent include aromatic polyvinyl compounds such as divinylbenzene and divinylnaphthalene; divinyl phthalate, divinyl isophthalate, divinyl terephthalate, divinyl homophthalate, divinyl trimesate / trivinyl, naphthalene dicarboxylic acid Polyvinyl esters of aromatic polyvalent carboxylic acids such as divinyl and divinyl biphenyl carboxylates; divinyl esters of nitrogen-containing aromatic compounds such as divinyl pyridine dicarboxylate; vinyl pyromutinate, vinyl furan carboxylate, pyrrole-2-carboxylic acid Vinyl esters of unsaturated heterocyclic compounds such as vinyl acetate and vinyl thiophenecarboxylate; butanediol methacrylate, hexanediol acrylate, octanediol methacrylate, decanediol acrylate (Meth) acrylic acid esters of linear polyhydric alcohols such as dodecanediol methacrylate; branches such as neopentyl glycol dimethacrylate, 2-hydroxy-1,3-diaacryloxypropane, (meth) of substituted polyhydric alcohols Acrylic acid esters; Polyethylene glycol di (meth) acrylate, Polypropylene polyethylene glycol di (meth) acrylates; Divinyl succinate, divinyl fumarate, vinyl / divinyl maleate, divinyl diglycolate, vinyl / divinyl itaconate, acetone dicarboxylic Divinyl acid, divinyl glutarate, divinyl 3,3′-thiodipropionate, trans-aconite divinyl / trivinyl, divinyl adipate, divinyl pimelate, divinyl suberate, divinyl azelate And polyvinyl esters of polyvalent carboxylic acids such as divinyl sebacate, divinyl dodecanedioate, divinyl brassylate, and the like. In the present invention, these crosslinking agents may be used alone or in combination of two or more.

  Of the above-mentioned cross-linking agents, the cross-linking agent in the present invention is a butane that can suppress the precipitation of the release agent on the toner surface during cooling in order not to make the binder resin unnecessarily high in the coalesced state. (Meth) acrylic acid esters of linear polyhydric alcohols such as diol methacrylate, hexanediol acrylate, octanediol methacrylate, decanediol acrylate, dodecanediol methacrylate; neopentyl glycol dimethacrylate, 2-hydroxy-1,3-diacri It is preferable to use branches such as loxypropane, (meth) acrylic acid esters of substituted polyhydric alcohols; polyethylene glycol di (meth) acrylate, polypropylene polyethylene glycol di (meth) acrylate and the like.

  The monomer emulsion described above is obtained by mixing the monomers with water and a surfactant. Emulsification is generally carried out at a temperature of about 5 to about 40 ° C, but monomer emulsions are formed at higher temperatures. In order to form a monomer emulsion, this mixture is usually stirred using a suitable mixing device, for example, a normal stirrer, a high-speed stirrer such as a homogenizer, or a container equipped with an external loop including an in-line mixing device. The mixing speed required for producing the emulsion depends on the type of apparatus used and the amount of the surfactant. However, the faster the mixing, the smaller the emulsion is produced and the higher the stability. Further, the time required for the formation of the emulsion is about 5 to 60 minutes although it is shortened if stirring is performed at a higher speed.

  As the surfactant used to form the monomer emulsion, an anionic surfactant, a cationic surfactant, a betaine (amphoteric) surfactant, and a nonionic surfactant can be appropriately selected and used.

  Specific examples of anionic surfactants include fatty acid soaps such as potassium laurate, sodium oleate, and castor oil sodium; sulfate esters such as octyl sulfate, lauryl sulfate, lauryl ether sulfate, and nonyl phenyl ether sulfate; lauryl sulfonate , Sodium alkylnaphthalene sulfonate such as dodecylbenzene sulfonate, triisopropyl naphthalene sulfonate, dibutyl naphthalene sulfonate; sulfone such as naphthalene sulfonate formalin condensate, monooctyl sulfosuccinate, dioctyl sulfosuccinate, lauric acid amide sulfonate, oleic acid amide sulfonate Acid salts; lauryl phosphate, isopropyl phosphate, nonylphenyl ether Phosphoric acid esters such as Sufeto; dialkyl sulfosuccinate salts such as sodium dioctyl sulfosuccinate; sulfosuccinate salts such as sulfosuccinate lauryl disodium; and the like.

  Specific examples of the cationic surfactant include laurylamine hydrochloride, stearylamine hydrochloride, oleylamine acetate, stearylamine acetate, stearylaminopropylamine acetate, and other amine salts; lauryltrimethylammonium chloride, dilauryldimethylammonium Chloride, distearyldimethylammonium chloride, distearyldimethylammonium chloride, lauryldihydroxyethylmethylammonium chloride, oleylbispolyoxyethylenemethylammonium chloride, lauroylaminopropyldimethylethylammonium ethosulphate, lauroylaminopropyldimethylhydroxyethylammonium perchlorate, alkylbenzene Trimethylammonium chloride, Quaternary ammonium salts such as quilts trimethyl ammonium chloride; and the like.

  Specific examples of the nonionic surfactant include alkyl ethers such as polyoxyethylene octyl ether, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether; polyoxyethylene octyl phenyl ether, polyoxy Alkyl phenyl ethers such as ethylene nonyl phenyl ether; alkyl esters such as polyoxyethylene laurate, polyoxyethylene stearate, polyoxyethylene oleate; polyoxyethylene lauryl amino ether, polyoxyethylene stearyl amino ether, polyoxyethylene Alkylamines such as oleyl amino ether, polyoxyethylene soybean amino ether, polyoxyethylene beef tallow amino ether; Alkyl amides such as ethylene lauric acid amide, polyoxyethylene stearic acid amide, polyoxyethylene oleic acid amide; vegetable oil ethers such as polyoxyethylene castor oil ether and polyoxyethylene rapeseed oil ether; lauric acid diethanolamide, stearic acid Alkanolamides such as diethanolamide and oleic acid diethanolamide; sorbitan ester ethers such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate And so on.

  Further, as the anionic surfactant used for producing the monomer emulsion, any anionic surfactant may be used as long as the desired emulsion and latex are produced and the toner performance is not adversely affected. Examples of the anionic surfactant used include, but are not limited to, diphenyl oxide disulfonates, alkylbenzene sulfonates, alkylnaphthalene sulfonates and sulfates, and mixtures thereof. The surfactants used in the preferred embodiment of the present invention are commercially available diphenyl oxide disulfonates, such as the Dowfax® series, available from Dow Chemical.

  Moreover, in order to adjust the molecular weight of the polymer to be produced, it is desirable to add a chain transfer agent to the above monomer emulsion. Examples of the chain transfer agent used in this embodiment include dodecanethiol, butanethiol, isooctyl 3-mercaptopropionate (IOMP), 2-methyl-5-tert-butylthiophenol, carbon tetrachloride, carbon tetrabromide, and the like. However, it is not limited to these. The chain transfer agent is used in an effective amount, for example from about 0.1 to about 10% by weight of the monomer in the monomer emulsion. Further, the chain transfer agent may be added in advance to the monomer emulsion, may be added after the addition of the monomer emulsion, or may be added simultaneously with the addition of the monomer emulsion.

  Also, a small amount of monomer emulsion is added to the aqueous phase to produce the seed polymer described above. The anionic surfactant contained in the aqueous phase is 20% by weight or less based on the total amount of the anionic surfactant used for producing the latex polymer. Desirably, the anionic surfactant contained in the aqueous phase is 0.5 to 10% by weight of the total amount of the anionic surfactant used to form the latex polymer. In the aqueous phase, any of the above-mentioned anionic surfactants may be used, and the anionic surfactant in the aqueous phase is the same as the anionic surfactant used for forming the monomer emulsion. But it can be different.

  The amount of monomer used to produce the seed polymer is typically about 0.25 to about 25% by weight of the total amount of monomer used to prepare the latex polymer. Desirably, the amount of monomer used to produce the seed polymer is about 0.5 to 10%, more desirably about 0.5 to 3% by weight of the total amount of monomer used to form the latex polymer.

  Examples of the above-mentioned free radical initiator (hereinafter referred to as “initiator”) include ammonium persulfate, potassium persulfate, sodium persulfate, ammonium persulfite, potassium persulfite, sodium persulfite, ammonium bisulfate, sodium bisulfate, , 1'-azobis (sodium 1-methylbutyronitrile-3-sulfonate), 4,4'-azobis (4-cyanovaleric acid), and the like, but are not limited thereto. Desirable initiators are persulfate initiators such as ammonium persulfate, potassium persulfate, sodium persulfate and the like. The initiator is usually added to the monomer emulsion and / or aqueous phase as an aqueous solution.

  The amount of initiator used to form the latex polymer is usually about 0.1 to about 10% by weight based on the total amount of monomers to be polymerized. In addition, 5 to 100% by weight, preferably 30 to 100% by weight of the total amount of initiator used for preparing the latex polymer is added in the seed polymerization stage.

  In the production of the seed polymer, emulsion polymerization is usually carried out at a temperature of about 35 to about 150 ° C, desirably about 50 to about 95 ° C. To maintain system stability, the initiator is usually added slowly to the emulsion. For example, the initiator is added over 5 minutes, preferably over 10 minutes.

  Next, the monomer is added to the seed polymer to complete the polymerization. The additional monomer may be emulsified in water as described above to form an emulsion, or the monomer may be used as it is. In the present embodiment, the additional monomer is added as the remaining amount of the monomer emulsion excluding a part of the monomer emulsion used during seed polymerization. The emulsion polymerization at the time of addition of the additional monomer is usually carried out at a temperature of about 35 to about 150 ° C, desirably about 50 to about 95 ° C. The additional monomer is usually added to the composition over an effective period of time, for example 0.5 to 8 hours, preferably 2 to 6 hours, but in the present invention all monomers used in the reaction are added during the addition of the additional monomer. When the emulsion is 100 wt%, it is important that the monomer emulsion addition amount per minute is 0.25 to 1.00 wt%.

  Further, an initiator may be added after the seed polymerization. If an initiator is added at this stage of the reaction, the initiator may or may not be the same type as that added in the production of the seed polymer. Initiators useful in this step of the process include hydrogen peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, p-methane hydroperoxide, benzoyl peroxide, tert-butyl peroxide, cumyl in addition to the initiators described above. Peroxide, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′- Azobisisobutyramide dihydrate, 2,2′-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, 2,2′-azobis [2- (5-methyl-2-imidazoline) -2-yl) propane] dihydrochloride and the like, but are not limited thereto.

  Specific examples of the latex polymer produced by the process of the present invention include poly (styrene-butadiene), poly (methyl methacrylate-butadiene), poly (ethyl methacrylate-butadiene), poly (propyl methacrylate-butadiene), poly (Butyl methacrylate-butadiene), poly (methyl acrylate-butadiene), poly (ethyl acrylate-butadiene), poly (propyl acrylate-butadiene), poly (butyl acrylate-butadiene), poly (styrene-isoprene) , Poly (methylstyrene-isoprene), poly (methyl methacrylate-isoprene), poly (ethyl methacrylate-isoprene), poly (propyl methacrylate-isoprene), poly (butyl methacrylate-isoprene), poly (methyl acrylate) -Isoprene , Poly (ethyl acrylate-isoprene), poly (propyl acrylate-isoprene), poly (butyl acrylate-isoprene), poly (styrene-butyl acrylate), poly (styrene-butyl methacrylate), poly (styrene- Butyl acrylate-acrylic acid), poly (styrene-butadiene-acrylic acid), poly (styrene-isoprene-acrylic acid), poly (styrene-butyl methacrylate-acrylic acid), poly (butyl methacrylate-butyl acrylate) , Poly (butyl methacrylate-acrylic acid), poly (styrene-butyl acrylate-acrylonitrile-acrylic acid), poly (acrylonitrile-butyl acrylate-acrylic acid), poly (styrene-butyl acrylate-acrylic acid 2-carboxyl) Ethyl), poly (styrene) Butadiene-2-carboxyethyl acrylate), poly (styrene-isoprene-2-carboxyethyl acrylate), poly (styrene-butyl methacrylate-2-carboxyethyl acrylate), poly (butyl methacrylate-butyl acrylate) 2-carboxyethyl acrylate), poly (butyl methacrylate-2-carboxyethyl acrylate), poly (styrene-butyl acrylate-acrylonitrile-2-carboxyethyl acrylate), poly (acrylonitrile-butyl acrylate-acrylic acid) 2-Carboxyethyl) and known polymers such as the above-mentioned branched / partially crosslinked copolymers, but are not limited thereto.

  The method for preparing a latex polymer in the present embodiment includes a deposit removal step of removing deposits in a polymerization reaction tank, which is a manufacturing apparatus, after the above-described latex polymer is manufactured. The deposit removal step in the present embodiment is performed either after the latex polymer in the polymerization reaction tank is discharged from the polymerization reaction tank after the polymerization, or after the latex polymer is manufactured and discharged several times by the manufacturing apparatus. In the manufacturing method, the deposit on the inner wall of the manufacturing apparatus is removed with high-pressure water. That is, when removing the deposits in the polymerization reaction tank, it may be performed for each batch of the polymerization reaction, but the polymerization is repeated several tens of times to several hundred batches, the deposits are stacked and deposited, When the part was peeled off and dropped off, and when the deposits deposited on the heat transfer surface clearly decreased the cooling and heating rate of the contents of the polymerization reaction tank and confirmed deterioration of the heat transfer efficiency. There may be.

  The pressure of the high-pressure water in the present embodiment is 100 Pma or more and 400 MPa or less, preferably 150 Pma or more and 250 Pma or less. With high-pressure water of less than 100 MPa, deposits formed in the polymerization reaction tank cannot be sufficiently removed. On the other hand, when high-pressure water exceeding 400 MPa is used, the inner wall surface of the polymerization reaction vessel is damaged, and the adhesion and growth of deposits are promoted in the polymerization.

  The flow rate of the high-pressure water for cleaning in the present embodiment is 1 L / min to 100 L / min, preferably 5 L / min to 50 L / min. When the flow rate of high-pressure water is less than 1 L / min, it is difficult to remove the deposits. On the other hand, when it exceeds 100 L / min, the load on the cleaning device increases and the inner wall of the polymerization reaction tank may be damaged. In the subsequent emulsion polymerization, adhesion and growth of the deposit are promoted.

  As water used as high-pressure water for cleaning in the present embodiment, ion-exchanged water or superreducible water (EKO-13) having an electric conductivity of 1 μS / cm or less is used, or an electric conductivity of 1 μS / cm. More than water may be used. Here, when water having an electric conductivity exceeding 1 μS / cm is used as the high-pressure water, ion-exchanged water or super-reducing water having an electric conductivity of 1 μS / cm or less at high pressure or normal pressure is used as the rinse water later. It is desirable to add EKO-13) into the polymerization reaction tank and wash it with friends to replace the water in the tank.

  As a manufacturing apparatus used for preparing the latex polymer in the present embodiment, a polymerization reactor or polymerization vessel having a general shape having a heating means such as a jacket and a heat transfer coil and a stirring means such as a stirring blade is selected. Can do. As the material for the polymerization reaction vessel and the polymerization vessel, those usually used such as stainless steel, glass, FRP (abbreviation of Fiber Reinforced Plastics, that is, fiber reinforced plastic) can be used. Further, the surface may be subjected to electrolytic polishing, Teflon (registered trademark) coating, or glass lining treatment. In addition, the baffle plate, temperature sensor, and nozzle installed as accessories may be made of the same material and processing as the above-described polymerization reaction tank and polymerization vessel.

  The high-pressure water cleaning apparatus in the present embodiment is usually composed of a high-pressure pump for applying pressure to the cleaning water, a pipe for sending the cleaning water, and a nozzle from which the cleaning water is attached to the tip thereof. It has an elevating mechanism.

  Moreover, the nozzle for high pressure washing in the high pressure water washing apparatus is preferably a single-hole or multiple-hole direct injection nozzle or a spray nozzle, and an injection angle of 20 ° to 160 ° at a distance of 5 to 200 mm with respect to the adhesion wall surface. Hereinafter, the deposit removal effect is increased by spraying at 45 ° to 135 °, more preferably 70 ° to 110 °. Here, when the high-pressure washing nozzle has a plurality of holes, the effect of removing the deposit is promoted by moving the nozzle almost parallel to the wall of the polymerization reaction vessel or polymerization vessel.

[Method for producing toner for developing electrostatic image]
The latex obtained by the above-described method for preparing a latex polymer is used for toner preparation by the following method. A flocculant and / or a charge additive and / or other additives are mixed with the latex polymer prepared by the method described in the present invention and a plurality of dispersions containing at least a colorant as required, and the resulting mixture is obtained. Is heated at a temperature near the Tg of the latex polymer, preferably Tg ± 10 ° C. of the latex polymer for an effective time, for example 1 to 8 hours, to form toner-sized aggregates. The aggregate suspension is then heated to a Tg of the latex polymer or higher, for example from about 60 to about 120 ° C. to coalesce or coalesce to granulate toner particles, which are filtered, etc. It is separated from the mother liquor by means, washed with ion-exchanged water or the like as necessary, and then dried.

  The latex polymer is usually present from about 75 to about 98% by weight of the toner. The size of the latex polymer suitable for the production method of the present invention is, for example, about 0.05 to about 1 μm, desirably 50 to 500 nm, as a volume average particle diameter measured with a microtrack. In the present embodiment, other sizes and effective amounts of latex polymer can be used.

  The colorant is usually present in an effective amount in the toner, for example from about 1 to about 15% by weight of the toner, desirably from about 3 to about 10% by weight.

  Specific examples of colorants such as pigments used in the production method of the present invention include carbon black such as REGAL 330 (registered trademark), Mobay magnetite, MO8029 (registered trademark), and MO8060 (registered trademark). ); Colombian magnetite, MAPICO BLACKS® and surface treated magnetite; Pfizer magnetite, CB4799®, CB5300®, CB5600®, MCX6369®; Bayer magnetite, BAYFERROX 8600®, 8610®; Northern Pigments Magnetite such as netite, NP-604 (registered trademark), NP-608 (registered trademark); Magnox magnetite, TMB-100 (registered trademark), or TMB-104 (registered trademark), and the like. However, it is not limited to these. Colored pigments and dyes such as cyan, magenta, yellow, red, green, brown, blue and / or mixtures thereof can also be used. Usually, cyan, magenta, or yellow pigments or dyes, or mixtures thereof are used.

  Specific examples of pigments include phthalocyanine, HELIOGEN blue L6900 (registered trademark), D6840 (registered trademark), D7080 (registered trademark), D7020 (registered trademark) manufactured by Paul Uhrich & Company, Inc. PYLAM Oil Blue (registered trademark), Pyram Oil Yellow (registered trademark), Pigment Blue 1 (registered trademark); Pigment Violet 1 manufactured by Dominion Color Corporation, Ltd., Toronto, Ontario (Registered trademark), Pigment Red 48 (registered trademark), Lemon Chrome Yellow DCC1026 (registered trademark), E.I. D. Toluidine Red (registered trademark), Bon Red C (registered trademark); NOVAPERM yellow FGL (registered trademark), HOSTAPERM pink E (registered trademark) manufactured by Hoechst; I. Examples include, but are not limited to, CINQUASIA magenta (registered trademark) manufactured by EI du Pont de Nemours & Company. Specific examples of magenta include 2,9-dimethyl-substituted quinacridone, an anthraquinone dye described as CI60710 and CI Disperse Red 15 in the color index, a diazo dye described as CI26050 and CI Solvent Red 19 in the color index, and the like. Is mentioned. Specific examples of cyan are described as copper = tetra (octadecylsulfonamido) phthalocyanine, CI74160 in color index, x-copper phthalocyanine pigment listed as CI pigment blue, CI69810 in color index, and special blue X-2137. Specific examples of yellow are diarylated yellow, 3,3-dichlorobenzidineacetoacetanilide, monoazo pigments described as CI 12700 and CI Solvent Yellow 16 as color indexes, and color indexes. Nitrophenylaminesulfonamide, 2,5-dimethoate described in Foron Yellow SE / GLN, CI Disperse Yellow 33 Shi sulfonanilide phenylazo-4'-chloro-2,5-dimethoxy acetoacetanilide, Permanent Yellow FGL, and the like. Colored magnetite such as a mixture of Mapico Black (registered trademark) and a cyan component can also be used as a pigment in the production method of the present invention.

The aggregating agent is used in an effective amount, for example, from about 0.01 to about 10% by weight of the toner. As the flocculant used, polyaluminum chloride (PAC), (dialkyl) phenylalkylammonium chloride, lauryltrimethylammonium chloride, (alkylbenzyl) methylammonium chloride, (alkyl) (benzyl) dimethylammonium bromide, chloride Benzalkonium, cetylpyridinium bromide, C ₁₂ , C ₁₅ , C ₁₇ trimethylammonium bromide, quaternized polyoxyethylene alkylamine halide salts, dodecylbenzyltriethylammonium chloride, Alkali Chemicals (Alcaril) MIRAPOL® and ALKAQUAT®, Kao Chemical (Kao), available from the Chemical Company Sanisol (registered trademark) (benzalkonium chloride) available from Chemicals, but not limited thereto.

  An effective amount of the charge control agent may be used, for example, 0.1 to 5% by weight of the toner. Suitable charge control agents include toners using alkylpyridinium halides, bisulfates, distearyldimethylammonium methylsulfate charge control agents, U.S. Pat. No. 3,944,493, U.S. Pat. , 007,293, U.S. Pat. No. 4,079,014, U.S. Pat. No. 4,394,430, U.S. Pat. No. 4,560,635, the entire contents of which are incorporated herein by reference. Examples thereof include, but are not limited to, control agents, negative charge control agents such as aluminum complexes, and the like.

  Examples of other additives used include, but are not limited to, waxes that act as mold release agents.

  Hereinafter, the present invention will be described in more detail with reference to examples. In addition, this invention is not limited only to these Examples. Also, those skilled in the art will understand that appropriate reagents, component ratios / concentrations may be used as needed to achieve specific product characteristics. Unless otherwise indicated, all parts and percentages are by weight.

(Latex polymer preparation process)
Sodium tetrapropyldiphenyloxide disulfonate (Dowax 2A1 (registered trademark)) as an anionic surfactant, ammonium persulfate as an initiator, decanediol diacrylate (A-DOD (registered trademark)) as a cross-linking agent, and charge control agent A latex polymer containing a styrene / n-butyl acrylate / β-CEA copolymer having a composition ratio of 80/20/2 was synthesized by an emulsion polymerization method using dodecanethiol.

  That is, 37.1 parts of deionized water and 0.05 part of Dowfax 2A1 (registered trademark) were placed in a jacketed reactor and stirred at 100 rpm, and the temperature was raised to 75 ° C. In a separate emulsification tank, the monomer mixture (32.0 parts styrene, 8.0 parts n-butyl acrylate, 0.8 parts 2-carboxyethyl acrylate (β-CEA), 0.2 part decanediol diacrylate (A-DOD)), 0.3 part 1-dodecanethiol, and 17.0 parts deionized water plus 0.8 part Dowfax 2A1 Was mixed for 60 minutes at 250 rpm at room temperature to prepare a monomer emulsion (monomer concentration was 69.4% by weight). Then, 1.2 parts of the seed monomer emulsion was taken from this monomer emulsion and put into a reactor (emulsion polymerization tank) with a pump over 10 minutes. After 10 minutes, an initiator solution prepared by dissolving 0.8 parts of ammonium persulfate in 2.9 parts of deionized water was added over 10 minutes. Stirring was further continued for 30 minutes to produce seed particles. The remaining monomer emulsion was added to the reactor at a rate of addition of 0.5 wt% / min of the total monomer emulsion. When the remainder of the monomer emulsion reaches 50% by weight of the total monomer emulsion, 0.3 parts of 1-dodecanethiol is newly added to the monomer emulsion and stirred for 10 minutes. Was added to the reactor at the same discharge flow rate as described above at a rate of 0.6 wt% / min. After the monomer addition, the composition was heated at 75 ° C. for 180 minutes to complete the reaction and allowed to cool. During the reaction, the reaction system was deoxygenated by flowing a nitrogen stream.

  As a result, latex having an Mw of 40,000, Mn of 12,400, onset Tg of 53 ° C. and an average particle size of 230 nm was obtained.

(Number of continuous polymerization)
After 90 batches of the above polymerization were performed, the latex polymer was discharged from the polymerization reaction vessel, and then the polymerization reactor was washed between batches with a low pressure water wash of 20 MPa or less. Adhesion could not be removed, accumulated, and it became difficult to control latex properties due to deterioration of heat transfer efficiency, making continuous production after 90 batches difficult. Further, many deposits were observed to fall off, and the deposits could not be discharged and stayed in the polymerization reaction tank.

(Reactor cleaning)
[Example 1]
For the polymerization reactor in the above state, an attempt was made to remove the deposits using a high-pressure washing device comprising a high-pressure pump, piping and an injection nozzle. Washing was carried out under the conditions of a jet pressure of 200 MPa, a high-pressure water flow rate of 13 L / min, direct heating, and a spray nozzle in such a manner that the wash water hits the angle of 90 ° with respect to the inner wall of the reactor at a distance of 100 mm. The cleaning time was 1 minute / cm ² per unit area. As a result, the deposited deposits were completely removed, and the reactor surface was in a mirror state. Further, no scratch was observed on the inner wall of the reactor. As for the water used, water with a large amount of impurities having an electric conductivity of 200 μS / cm was used at the initial stage of washing, and 1 μS / cm of ion-exchanged water was used at the normal pressure for rinsing at the time of finishing. .

[Example 2]
For the polymerization reactor in the above state, an attempt was made to remove the deposits using a high-pressure washing device comprising a high-pressure pump, piping and an injection nozzle. Washing was carried out under conditions of a jet pressure of 110 MPa, a high-pressure water flow rate of 100 L / min, direct heating, and a spray nozzle so that the wash water hits an angle of 90 ° with respect to the inner wall of the reactor at a distance of 100 mm. The cleaning time until the reactor surface was mirror-finished was 2 minutes / cm ² per unit area, which required more time than Example 1. Further, no scratch was observed on the inner wall of the reactor. As for the water used, water with a large amount of impurities having an electric conductivity of 200 μS / cm was used at the initial stage of washing, and 1 μS / cm of ion-exchanged water was used at the normal pressure for rinsing at the time of finishing. .

[Example 3]
For the polymerization reactor in the above state, an attempt was made to remove the deposits using a high-pressure washing apparatus comprising a high-pressure pump, piping, and an injection nozzle. Washing was carried out under the conditions of a jet pressure of 400 MPa, a high-pressure water flow rate of 1 L / min, direct heating, and a spray nozzle in such a manner that the wash water was at an angle of 90 ° with respect to the inner wall of the reactor at a distance of 100 mm. The cleaning time was 1 minute / cm ² per unit area. As a result, the deposited deposits could be completely removed, the reactor surface was in a mirror state, and no damage was observed on the inner wall of the reactor. As for the water used, water with a large amount of impurities having an electric conductivity of 200 μS / cm was used at the initial stage of washing, and 1 μS / cm of ion-exchanged water was used at the normal pressure for rinsing at the time of finishing. .

[Example 4]
For the polymerization reactor in the above state, an attempt was made to remove deposits by using a high-pressure cleaning device consisting of a high-pressure pump (Sugino Machine AQUA2500), piping, and injection nozzle. Washing was carried out under the conditions of a jet pressure of 150 MPa, a high-pressure water flow rate of 50 L / min, direct heating, and a spray nozzle in such a manner that the wash water hits the angle of 90 ° with respect to the inner wall of the reactor at a distance of 100 mm. The cleaning time until the reactor surface was mirror-finished was 1.5 minutes / cm ² per unit area. Further, no scratch was observed on the inner wall of the reactor. As for the water used, water with a large amount of impurities having an electric conductivity of 200 μS / cm was used at the initial stage of washing, and 1 μS / cm of ion-exchanged water was used at the normal pressure for rinsing at the time of finishing. .

[Example 5]
For the polymerization reactor in the above state, an attempt was made to remove deposits by using a high-pressure cleaning device consisting of a high-pressure pump (Sugino Machine AQUA2500), piping, and injection nozzle. Washing was carried out under conditions of injection pressure of 250 MPa, high-pressure water flow rate of 5 L / min, direct heating, and a spray nozzle in such a manner that the wash water was at an angle of 90 ° with respect to the inner wall of the reactor at a distance of 100 mm. The cleaning time was 1 minute / cm ² per unit area. As a result, the deposited deposits were completely removed, and the reactor surface was in a mirror state. Further, no scratch was observed on the inner wall of the reactor. As the water used, ion-exchanged water having an electric conductivity of 1 μS / cm was used at the initial stage of washing.

[Comparative Example 1]
For the polymerization reactor in the above state, an attempt was made to remove deposits by using a high-pressure cleaning device consisting of a high-pressure pump (Sugino Machine AQUA2500), piping, and injection nozzle. Washing was carried out by using a spray pressure of 50 MPa, a high-pressure water flow rate of 100 L / min, direct heating, and a spray nozzle in such a manner that the wash water was at an angle of 90 ° with respect to the inner wall of the reactor at a distance of 100 mm. Even if the cleaning time was set to 4 minutes / cm ² per unit area, deposited deposits could not be removed. As for the water used, water with a large amount of impurities having an electric conductivity of 200 μS / cm was used at the initial stage of washing, and 1 μS / cm of ion-exchanged water was used at the normal pressure for rinsing at the time of finishing. .

[Comparative Example 2]
For the polymerization reactor in the above state, an attempt was made to remove the deposits using a high-pressure washing device comprising a high-pressure pump, piping and an injection nozzle. Washing was carried out by using a spray pressure of 100 MPa, a high-pressure water flow rate of 13 L / min, direct heating, and a spray nozzle in such a manner that the wash water hits the angle of 90 ° with respect to the inner wall of the reactor at a distance of 100 mm. The cleaning time was 2.5 minutes / cm ² per unit area, and the deposits could not be completely removed. As for the water used, water with a large amount of impurities having an electric conductivity of 200 μS / cm was used at the initial stage of washing, and 1 μS / cm of ion exchange water was used at normal pressure for rinsing at the time of finishing. .

[Comparative Example 3]
For the polymerization reactor in the above state, an attempt was made to remove the deposits using a high-pressure washing device comprising a high-pressure pump, piping and an injection nozzle. Washing was carried out under conditions of a jet pressure of 450 MPa, a high-pressure water flow rate of 13 L / min, direct heating, and a spray nozzle so that the wash water hits an angle of 90 ° with respect to the inner wall of the reactor at a distance of 100 mm. The cleaning time was 1 minute / cm ² per unit area. As a result, the deposited deposits were completely removed, and the reactor surface was in a mirror state. However, scratches were observed on the inner wall of the reactor with the naked eye. As for the water used, water with a large amount of impurities having an electric conductivity of 200 μS / cm was used at the initial stage of washing, and 1 μS / cm of ion-exchanged water was used at the normal pressure for rinsing at the time of finishing. .

Production of Latex and Toner after High Pressure Washing In Examples 1 to 5 and Comparative Examples 1 to 3, toners were prepared by the following methods using the latex polymer obtained in the first batch after washing. To 600 g of ion-exchanged water, 250 g of latex, 70 g of 20% carbon black dispersion (Regal 330 (registered trademark)) and 60 g of 30% wax dispersion (polyethylene P725 wax) were added and mixed for 5 minutes with a homogenizer. A controlled amount of 10% polyaluminum chloride solution was added to this mixture, mixed again for 5 minutes, and then heated to 50 ° C. with stirring to aggregate the particles. When the aggregate particle size reaches 5.0 μm, 120 g of latex is newly added to form an outer shell, and after 30 minutes of aggregation, the pH of the slurry is adjusted to 6.0 using 1% NaOH. Adjusted to raise the reactor temperature to 95 ° C. After 6 hours at this temperature, the mixture was allowed to cool and filtered to separate the particles from the mother liquor, followed by washing and drying.

  In Examples 1 to 5, no problem occurred in the toner adjustment process and the toner characteristics. Moreover, about Examples 1-5, after high-pressure water washing | cleaning, heat-transfer efficiency returned to the original level of manufacture, adhesion deposits disappeared, and the fallen deposits were not observed. Continuous production was carried out as it was, but continuous production of 85 batches or more was possible until the next cleaning was required, and toner production and coarse powder were not generated, and GSD could also be produced stably (see Table 1). )

  On the other hand, in Comparative Example 1, the adhesion removal effect is small in the high-pressure water washing, and it becomes difficult to maintain the latex polymer characteristics in four continuous batches in the subsequent manufacturing process. As a result, the amount of coarse powder in toner adjustment also increases. GSD worsened. In Comparative Example 2, the adhesion removal effect of high-pressure water washing is small, and it becomes difficult to maintain the latex polymer characteristics in 10 batches in the subsequent manufacturing process. As a result, the amount of coarse powder in toner adjustment increases, and GSD is reduced. It got worse. In Comparative Example 3, it was possible to maintain latex polymer properties up to 90 continuous batches. However, slight scratches were seen on the surface to be cleaned of the polymerization reactor, and it was judged that continuous cleaning at this pressure was not possible (see Table 1).

  The particle size distribution measurement in the present invention will be described.

  A Coulter counter TA-II type (manufactured by Beckman Coulter, Inc.) is used as the measuring apparatus, and ISOTON-II (manufactured by Beckman Coulter, Inc.) is used as the electrolyte.

  As a measuring method, 0.5 to 50 mg of a measurement sample is added to 2 ml of a 5% aqueous solution of a surfactant, preferably sodium alkylbenzenesulfonate as a dispersant. This is added to 100 to 150 ml of the electrolytic solution.

  The electrolyte solution in which the sample is suspended is dispersed for about 1 minute with an ultrasonic disperser, and the particle size distribution of particles of 0.6 to 18 μm is measured by using the Coulter counter TA-II with an aperture diameter of 30 μm. Thus, a volume average distribution and a number average distribution are obtained. The number of particles to be measured is 50,000. A weight average particle diameter is obtained from the volume average distribution and number average distribution thus obtained.

The particle size distribution of the toner in the present invention can be represented by a particle size distribution index GSD. The GSD can be expressed by the following formula.
GSD = [(d16 / d84)] ^0.5

  In the above formula, d16, d50, and d84 indicate the diameters of 16%, 50%, and 84%, respectively, counted from the large particle diameter side of the toner, and the numerical values are in the order of d16> d50> d84. It can be said that the smaller the GSD, the more uniform the toner. The GSD includes those calculated from the number average particle diameter and those calculated from the volume average particle diameter. The GSD of the toner in the present invention employs the GSD calculated from the volume average particle diameter.

  The preferable range of GSD is 1.4 or less, more preferably 1.27 or less, and still more preferably 1.25 or less. If the GSD exceeds 1.3, not only the image quality deteriorates, but also the fine powder increases, so the life of the carrier is shortened, which is not preferable.

  According to the above invention, a latex polymer satisfying desired characteristics can be produced stably and efficiently, whereby a high-quality emulsion polymerization aggregation toner can be obtained.

  It can be used for the purpose of producing a desired latex polymer stably and almost continuously, and for the purpose of producing a toner for developing an electrostatic image having a high yield and high image quality.

Claims (3)

In the method for preparing the latex polymer,
After the latex polymer is prepared, every time the latex polymer is discharged from the manufacturing apparatus or after the latex polymer is prepared and discharged a plurality of times in the manufacturing apparatus, the inner wall surface deposit on the manufacturing apparatus is increased to a high pressure of 100 to 400 MPa. A method for producing a latex polymer, wherein the latex polymer is removed with water. (I) adding a small amount of a monomer emulsion to the aqueous phase, starting seed polymerization to produce a polymer, and (ii) adding a monomer emulsion to the composition produced in the step (i) to carry out emulsion polymerization. A method of preparing a latex polymer comprising the steps of:
A method for producing a latex polymer, wherein deposits on a surface to be cleaned of a production apparatus used for the latex polymer adjustment method are removed with high-pressure water of 100 to 400 MPa. In the method for producing a toner for developing an electrostatic charge image, the aggregated particles are formed by aggregating the fine particles in a dispersion obtained by dispersing at least resin fine particles, and then the aggregated particles are fused by heating.
A method for producing a toner for developing an electrostatic charge image, wherein the resin fine particles are resin fine particles obtained by the method for preparing a latex polymer according to claim 1.