JP2012048184A - Method for reproducing solid-liquid separation filter of toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for reproducing a solid-liquid separation filter of toner capable of effectively reproducing the solid-liquid separation filter with a reduced damage thereon.SOLUTION: A method for reproducing a solid-liquid separation filter of toner, to be used in a production process of toner for an electrostatic charge image development, includes washing the filter used for solid-liquid separation of toner particles obtained through polymerization at a temperature higher than a melting point of wax contained in the toner particles. The filter is preferably washed with hot water or steam and the solid-liquid separation filter is preferably made of a cloth. The present invention enables toner for the electrostatic charge image development to be produced with the filter reproduced by the method.

Description

  The present invention relates to a method for regenerating a solid-liquid separation filter used in a process for producing an electrostatic charge image developing toner. The present invention also relates to a method for producing a toner for developing an electrostatic image using a regenerated filter.

  Conventionally, a method for producing an electrostatic image developing toner is roughly classified into a pulverization method and a polymerization method. In the pulverization method, raw materials such as resin and colorant are mixed, kneaded, cooled, finely pulverized with a jet mill, etc., classified as necessary, added with additives, and then filled into a container after sieving. Become a product. In addition, in the polymerization method, it is necessary to polymerize raw materials such as monomers and waxes, add a colorant, a charge control agent, etc., and if necessary, aggregate the obtained polymer particles and then go through dehydration, washing and drying processes. Depending on the case, additives are added and then filled into a container to obtain a product.

In the washing process of the production of the toner by the polymerization method, a filter is generally used for solid-liquid separation of the washed toner particles and the washing liquid, and an apparatus such as a filter press or a centrifuge is used.
When a filter is used, the efficiency of solid-liquid separation may decrease due to clogging of the filter with use, and productivity may be reduced. This productivity is maintained by periodically or temporarily replacing the filter, but it is desirable to regenerate the used filter from the viewpoint of cost. A number of filter regeneration methods are exemplified in the following Patent Document 1 and the like. However, the method of mechanically removing clogging with a high-pressure jet stream or a brush is a condition of the filter in order to damage the filter. Depending on the type of filter, the regenerated filter may not be able to exhibit its original performance due to leakage of particles, and the regeneration method using a cleaning agent is more costly for processing a solution containing the cleaning agent. Each of the exemplified methods is not a preferred method.

JP 2004-258609 A

  SUMMARY An advantage of some aspects of the invention is that it reduces damage to a toner solid-liquid separation filter and efficiently regenerates the filter.

The present inventor has determined that the cause of clogging of the filter is mainly wax particles that have been released without being taken into the toner with a certain probability, and the filter can effectively remove the wax particles. As a result of studying it as indispensable for reproduction of the present invention, the present invention has been achieved.
The gist of the present invention is as follows.
(1) In the production process of the electrostatic image developing toner, the toner particles obtained by polymerization are solid-liquid separated by a filter, and then the filter is washed at a temperature equal to or higher than the melting point of the wax contained in the toner particles. A method for regenerating a filter for toner solid-liquid separation.
(2) The method for regenerating a filter for toner solid-liquid separation according to (1), wherein the washing is performed with hot water or steam.
(3) The method for regenerating a toner solid-liquid separation filter according to (1) or (2), wherein the solid-liquid separation filter is formed of a cloth.
(4) A toner for developing an electrostatic charge image, wherein the toner particles obtained by polymerization are subjected to solid-liquid separation using the regenerated filter described in any one of (1) to (3). Manufacturing method.

  The regeneration method of the present invention causes less damage to the filter and increases the number of reusable times per filter as compared to a known mechanical cleaning method using a high-pressure jetter or brush for a toner solid-liquid separation filter. Also, it is very effective from the viewpoint of cost.

FIG. 5 is a diagram illustrating a relationship between the passage of time for each toner cleaning frequency and the amount of water passing through a filter in the embodiment.

The method for regenerating a toner solid-liquid separation filter of the present invention can be employed in a normal polymerization toner manufacturing process.
The production method of the polymerized toner is roughly divided into a suspension polymerization method and an emulsion polymerization method. The present invention can be applied to any polymerization method, but here, a polymerized toner obtained by an emulsion polymerization method will be mainly described as an example.

  The usual method for producing polymerized toner is to first polymerize monomers, waxes, etc. as raw materials in a polymerization tank in water in the presence of a polymerization initiator and, if necessary, a chain transfer agent. Auxiliary raw materials such as a control agent are added and heated to agglomerate, melt and cool and solidify the polymer particles, and then various additives are added to obtain a toner material. As the toner raw material, a monomer and a wax are used as essential components. For example, a colorant, a charge control agent, and other toner property imparting agents can be used as necessary.

  The monomer used in the present invention is not particularly limited as long as it is a monomer used in a polymerized toner, and various known monomers having acidic polar groups or basic polar groups can be used. Examples of the monomer having an acidic polar group include monomers having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid, fumaric acid and cinnamic acid, and monomers having a sulfonic acid group such as sulfonated styrene.

  The monomer having a basic polar group has an amino group such as aminostyrene and a quaternary salt thereof, a nitrogen-containing heterocyclic ring-containing monomer such as vinylpyridine and vinylpyrrolidone, and dimethylaminoethyl acrylate and diethylaminoethyl methacrylate ( (Meth) acrylic acid esters and (meth) acrylic acid esters having an ammonium salt quaternized with these amino groups, acrylamide, N-propylacrylamide, N, N-dimethylacrylamide, N, N-di Mention may be made of propylacrylamide, N, N-dibutylacrylamide and acrylic acid amide.

  Examples of other comonomers include styrenes such as styrene, methylstyrene, chlorostyrene, dichlorostyrene, p-tert-butylstyrene, pn-butylstyrene, and pn-nonylstyrene, methyl acrylate, ethyl acrylate, Propyl acrylate, n-butyl acrylate, isobutyl acrylate, hydroxyethyl acrylate, ethyl hexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, hydroxyethyl methacrylate, Mention may be made of (meth) acrylic acid esters such as ethylhexyl methacrylate. Of these, styrene, butyl acrylate and the like are particularly preferable.

  These monomers are used alone or in combination, and at that time, it is preferable to determine that the glass transition temperature of the polymer obtained after polymerization is 40 to 80 ° C. If the glass transition temperature is too high, the fixing strength is weakened. In full-color toners, the transparency of the OHP sheet may be deteriorated, and the gloss of the plain paper may be lowered. When the glass transition temperature is too low, the storage stability of the toner becomes too bad, causing a problem. In particular, acrylic acid is suitably used as the monomer having an acidic polar group, and styrene, acrylic acid ester, and methacrylic acid ester are suitably used as the other monomers.

  As the wax, any of known waxes used for polymerized toners can be used. Specifically, olefin waxes such as low molecular weight polyethylene, low molecular weight polypropylene, and copolymerized polyethylene, paraffin wax, and behen. Ester waxes having long chain aliphatic groups such as behenyl acid, montanate ester, stearyl stearate, hydrogenated castor oil, plant waxes such as carnauba wax, ketones having long chain alkyl groups such as distearyl ketone, alkyl groups And higher fatty acids such as stearic acid, long-chain fatty acid alcohols, long-chain fatty acid polyhydric alcohols such as pentaerythritol, and partial ester forms thereof, higher fatty acid amides such as oleic acid amide and stearic acid amide, etc. . Among these waxes, a wax having a melting point of 100 ° C. or lower is more preferable in order to improve fixability, and a more preferable wax has a melting point in the range of 40 to 90 ° C., particularly preferably in the range of 50 to 80 ° C. It is. When the melting point exceeds 100 ° C., the effect of reducing the fixing temperature is poor.

In the emulsion polymerization method, wax fine particles are obtained by emulsifying the wax in the presence of at least one emulsifier selected from known cationic surfactants, anionic surfactants, and nonionic surfactants. Two or more of these surfactants may be used in combination.
Specific examples of the cationic surfactant include dodecyl ammonium chloride, dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, dodecyl pyridinium bromide, hexadecyl trimethyl ammonium bromide, and the like.

Specific examples of the anionic surfactant include fatty acid soaps such as sodium stearate and sodium dodecanoate, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and sodium lauryl sulfate.
Further, specific examples of nonionic surfactants include dodecyl polyoxyethylene ether, hexadecyl polyoxyethylene ether, nonylphenyl polyoxyethylene ether, lauryl polyoxyethylene ether, sorbitan monooleate polyoxyethylene ether, monodecanoyl Examples thereof include sucrose.

  Polymerization initiators used include persulfates such as potassium persulfate, sodium persulfate, and ammonium persulfate, and redox initiators composed of these persulfates as a component and a reducing agent such as sodium acid sulfite. Water-soluble polymerization initiators such as hydrogen oxide, 4,4′-azobiscyanovaleric acid, t-butyl hydroperoxide, cumene hydroperoxide, and ferrous salts containing these water-soluble polymerizable initiators as one component Redox initiator systems, benzoyl peroxide, 2,2′-azobis-isobutyronitrile, etc. in combination with other reducing agents are used. These polymerization initiators may be added to the polymerization system before, simultaneously with the addition of the monomer, or after the addition, and these addition methods may be combined as necessary.

A known chain transfer agent can be used if necessary. Specific examples of such chain transfer agent include t-dodecyl mercaptan, 2-mercaptoethanol, diisopropylxanthogen, carbon tetrachloride, trichlorobromo. Methane, etc. The chain transfer agent may be used alone or in combination of two or more, and is used in an amount of 0 to 5% by mass based on the polymerizable monomer.
The aforementioned waxes are dispersed in the presence of an emulsifier to form an emulsion, which is subjected to resin seed polymerization. The average particle diameter of the wax particles in the emulsion is preferably 0.01 μm to 3 μm, more preferably 0.03 to 1 μm, and particularly preferably 0.05 to 0.8 μm. The average particle diameter can be measured using, for example, Microtrac UPA (manufactured by Nikkiso Co., Ltd.). If the average particle size of the wax particles is too large, the average particle size of the polymer particles obtained by seed polymerization tends to be too large, which may be inappropriate for applications requiring high resolution as a toner. . On the other hand, when the average particle size of the wax particles is too small, the wax content in the polymer primary particles after seed polymerization becomes too low, and the effect of the wax tends to be low.

  In seed polymerization in the presence of a wax emulsion, a monomer having a polar group (a monomer having an acidic polar group or a monomer having a basic functional group) and other monomers are sequentially added to the wax. Polymerization proceeds in the contained emulsion. At this time, the monomers may be added separately, or a plurality of monomers may be mixed and added in advance. Further, it is possible to change the monomer composition during the monomer addition. The monomer may be added as it is, or may be added as an emulsion mixed and adjusted in advance with water or a surfactant. As the surfactant, one or two or more combined systems are selected from the above surfactants.

In proceeding the seed polymerization, a certain amount of emulsifier may be added to the wax emulsion. Further, the addition timing of the polymerization initiator may be any before the monomer addition, at the same time as the monomer addition, after the monomer addition, or may be a combination of these addition methods.
The polymer primary particles obtained as described above are polymer particles substantially including a wax, and the morphology thereof takes any form such as a core-shell type, a phase separation type, and an occlusion type. It may be a mixture of these forms. Particularly preferred is the core-shell type. The wax is usually used in an amount of 1 to 40 parts by mass, preferably 2 to 35 parts by mass, and more preferably 5 to 30 parts by mass with respect to 100 parts by mass of the binder resin. In addition, components other than wax, such as pigments, charge control agents, etc., may be used as seeds at the same time within the scope of the present invention. Further, a colorant may be used by dissolving or dispersing in a monomer or wax.

  The average particle diameter of the polymer primary particles is usually in the range of 0.05 μm to 3 μm, preferably 0.1 μm to 1 μm, more preferably 0.1 μm to 0.5 μm. The average particle diameter can be measured using, for example, the above-described Microtrac UPA. If the particle size is too small, it tends to be difficult to control the aggregation rate. On the other hand, if the particle size is too large, the toner particle size obtained by agglomeration becomes large, which may be inappropriate for applications that require high resolution as a toner.

In the aggregation step, the polymer primary particles obtained as described above have a weight average particle diameter of about 3 to 12 μm, preferably about Aggregated particles are generated so as to be in the range of 5 to 10 μm.
A known stirring vessel having a stirring blade can be used in the polymerization and aggregation processes. Heat treatment may be performed in order to make the aggregation of particles stronger.

In obtaining the polymer primary particles in the above polymerization step, a colorant such as a pigment may be used as a seed simultaneously with the wax, or the colorant may be used by dissolving or dispersing in a monomer or wax. However, it is preferable to form a polymerized toner by aggregating the colorant primary particles simultaneously with the polymer primary particles in the aggregation step to form associated particles. At this time, polymer primary particles encapsulating wax are used, but two or more kinds of polymer primary particles may be used as necessary. Moreover, as a coloring agent used here, any of an inorganic pigment, an organic pigment, an organic dye, or these combinations may be sufficient. Specific examples of these include carbon black, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa yellow, rhodamine dyes, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane dye, monoazo, disazo. Any known dyes and pigments such as those based on azo dyes and condensed azo dyes can be used alone or in combination. In the case of a full color toner, it is preferable to use benzidine yellow for yellow, monoazo and condensed azo dyes, magenta for quinacridone and monoazo dyes, and cyan for phthalocyanine blue. The colorant is usually used so as to be 3 to 20 parts by mass with respect to 100 parts by mass of the binder resin.
These colorants are also emulsified in water in the presence of an emulsifier and used in the form of an emulsion. The average particle size is preferably 0.01 to 3 μm.

  As the charge control agent, any known one can be used alone or in combination. In consideration of color toner adaptability (the charge control agent itself is colorless or light and there is no color tone problem on the toner), the quaternary ammonium salt compound is positively charged and the salicylic acid or alkylsalicylic acid chromium is negatively charged. Metal salts with zinc, aluminum and the like, metal complexes, metal salts of benzylic acid, metal complexes, amide compounds, phenol compounds, naphthol compounds, phenolamide compounds and the like are preferable. The amount of use may be determined by the desired charge amount for the toner, but usually 0.01 to 10 parts by weight, more preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the binder resin.

  Furthermore, when obtaining the polymer primary particles, the charge control agent may be used as a seed simultaneously with the wax, or the charge control agent may be dissolved or dispersed in a monomer or wax. It is preferable to form a polymerized toner by aggregating the control agent primary particles to form associated particles. In this case, the charge control agent is also used as an emulsion having an average particle size of 0.01 to 3 μm in water.

The timing of addition may be simultaneously added and aggregated in the step of aggregating the polymer primary particles and the colorant primary particles, or may be added at the stage where these primary particles are associated to form secondary particles. Further, it may be added after the associated particles have grown to the final particle size of the polymerized toner.
In the production of the polymerized toner, after the aggregated particle size has grown substantially to the final toner particle size, a binder resin emulsion of the same or different type is further added to adhere the particles to the surface. Thus, the toner properties near the surface can be modified.

  The dispersion of aggregated particles obtained as described above is cooled to 50 ° C. or lower, and solid-liquid separation is performed using a filter to obtain a toner particle cake. Further, the toner particles are washed by hanging water on the toner particle cake. In this cleaning process, impurities adhering to the toner particles are reduced, and the toner performance can be exhibited over a wide range of environments, so that ion-exchanged water having an electric conductivity of 2 μS or less is used, and the electric conductivity of the filtrate is 5 μS. It is desirable to wash it until it becomes below.

The electric conductivity of ion-exchanged water or filtrate can be measured with a normal electric conductivity meter, and “CM-25R” (manufactured by Toa DKK) can be mentioned as an example of a measuring instrument.
Filters include mesh woven with metal wires such as SUS316L, fabrics made by weaving fibers such as polyester and polypropylene, non-woven fabrics, filter paper, etc. Filters made of fabric that are easy to handle and relatively durable A filter press or a centrifuge equipped with a filter is preferable as the filtration device.

The filter is used for solid-liquid separation of the toner particle cake and water, etc., and solid-liquid separation in the suspension washing with water. Usually, the same filter is used continuously, but different types of filters are used for each solid-liquid separation. It can also be used for separation operations.
If the filter is repeatedly used a plurality of times, clogging or the like occurs, and the solid-liquid separation efficiency decreases, so it is necessary to regenerate the filter.

  The present invention is characterized in that washing is performed at a temperature equal to or higher than the melting point of the wax contained in the toner as a regenerating operation. Cleaning is preferably performed at a temperature equal to or higher than the melting point of the wax using a liquid that does not substantially contain solids such as water and organic solvents, or vapor of the liquid, and is performed with hot water or steam from the viewpoint of cleaning efficiency. preferable. Washing is performed at a temperature equal to or higher than the melting point of the wax, preferably at least 3 ° C. higher than the melting point of the wax, more preferably higher than 10 ° C. higher than the melting point of the wax. In the case of hot water, the upper limit of the temperature is not particularly limited, but is usually below the boiling point. When using a commercially available steam cleaner, there are various types of discharge temperatures ranging from 80 ° C to 160 ° C. However, it does not damage the cloth filter, and the toner particles that remain slightly on the filter surface are stuck to the filter. From the viewpoint of avoiding this, a discharge temperature up to about 100 ° C. (for example, Condor Super Steam Jet SP-100: discharge temperature 97 ° C.) is desirable. By making the hot water into a specific temperature range, the filter can be regenerated efficiently, and physical damage to the filter is extremely small compared to known high-pressure jets and mechanical means such as brushes. Therefore, it can be used repeatedly.

When a plurality of types of wax are used, the cleaning temperature is determined based on the melting point of the wax having the higher melting point.
The cleaning means in the present invention may be any means as long as it is a means for bringing a liquid or vapor into contact with the filter. For example, a method of passing hot water through the filter, a method of immersing the filter in hot water, Examples thereof include a method in which hot water is applied to the filter surface, a method in which water vapor is applied using a commercially available steam cleaning machine, and a method in which water or hot water is washed away after water vapor is applied.

When washing the filter with a method of passing hot water, water may be passed from either direction with respect to the filter, but in the method of applying hot water or the method of washing by applying steam, From the viewpoint of more effectively applying heat to the clogging substance, it is preferable to perform on the surface holding the toner particles.
When the filter regeneration process is performed, it can be appropriately selected every time a solid-liquid separation operation is performed, as appropriate, depending on the state of separation efficiency reduction. For example, the regeneration process is performed when the liquid passing efficiency decreases to a predetermined ratio (for example, 50% or less, 40% or less, etc.) of the new filter, or when the total liquid passing amount or the aeration amount of the filter reaches a predetermined amount. It is preferable.

The end point of the regeneration treatment by washing according to the present invention can be determined by various methods. For example, the ratio can be determined when the ratio of the flow rate of the filter to the supplied liquid is 90% or more of the unused filter, when the amount of liquid to be cleaned, and when the amount of vapor reaches a predetermined amount.
The toner particle cake obtained by the washing step can be dried using an air dryer, a fluid dryer, a vacuum dryer, or a combination of these to obtain a polymerized toner.

The toner of the present invention can be used together with additives such as a fluidizing agent, if necessary, and specific examples of such fluidizing agents include fine powders such as hydrophobic silica, titanium oxide, and aluminum oxide. Usually, 0.01 to 5 parts by mass, preferably 0.1 to 3 parts by mass is used with respect to 100 parts by mass of the binder resin.
In addition, as various toner property imparting agents, inorganic fine particles such as titania, alumina, silica and the like can be used to improve fluidity and aggregation resistance.

  These toner property-imparting agents are usually used at a ratio of 0.1 to 10 parts by mass per 100 parts by mass of the binder resin. Further, when the toner is a magnetic toner, it can contain magnetic particles such as ferrite and magnetite, as well as alloys or compounds containing ferromagnetic elements such as iron, cobalt, and nickel. The magnetic particles are usually used at a ratio of 20 to 70 parts by mass per 100 parts by mass of the binder resin.

  When the above-mentioned toner property imparting agent is externally added to the polymerized toner, each is blended in a predetermined amount, and then stirred and mixed with a high-speed stirrer that gives shearing force to the powder such as a Henschel mixer or a super mixer. Is good. At that time, since heat is generated inside the external processing apparatus and agglomerates are likely to be generated, the temperature may be adjusted by means such as cooling the periphery of the external processing apparatus with water or the like. In that case, the temperature inside the external processing machine should be lower than the glass transition temperature of the resin of the polymerized toner, specifically 5 to 20 ° C., preferably about 10 ° C.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not restrict | limited at all by the following Examples, unless the summary is exceeded.
Example 1
<Manufacture of wax emulsion A>
20 parts by weight of paraffin wax (HNP9: Nippon Seiwa Co., Ltd., melting point: 77 ° C.) was added to a 20% by weight aqueous solution of anionic surfactant (Neogen S-20A: sodium dodecylbenzenesulfonate aqueous solution, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., hereinafter “20% An emulsion of paraffin wax (hereinafter abbreviated as “Wax Emulsion A”) was prepared by emulsifying under high-pressure shearing in addition to 1.44 parts by mass of 1.44 parts by mass of “DBS aqueous solution”. . The volume average particle diameter (mv) measured with Microtrac UPA was 0.25 μm.

The melting point of the wax was measured using a DSC-20 manufactured by Seiko Instruments Inc. at a temperature increase rate of 10 ° C./min, and the temperature was the peak apex temperature showing the maximum endotherm in the DSC curve.
<Production of polymer primary particle emulsion B1>
A reactor equipped with a stirrer (three blades), a heating / cooling device, and a raw material / auxiliary charging device was charged with 35.6 parts by mass of the wax emulsion A and 283 parts by mass of ion-exchanged water. The temperature was raised to 90 ° C. under an air stream. While stirring at a peripheral speed of 2.78 m / s at the tip of the stirring blade, a mixture of <polymerizable monomers etc.> in Table 1 and <emulsifier aqueous solution> was added over 5 hours. The time at which the mixture was started to be dropped was defined as “polymerization start”, and 30 minutes after “polymerization start”, <Initiator aqueous solution-1> was added over 4.5 hours in parallel with the above operation. After the addition of the mixture and <initiator aqueous solution-1> was completed, <initiator aqueous solution-2> was added over 2 hours. Stirring was further continued after the addition of <Initiator aqueous solution-2>, and the internal temperature was maintained at 90 ° C. for 1 hour.

[Table 1]
[Polymerizable monomers, etc.]
Styrene 76.75 parts by weight Butyl acrylate 23.25 parts by weight Acrylic acid 1.5 parts by weight Hexanediol diacrylate 0.7 parts by weight Trichlorobromomethane 1.0 part by weight
[Emulsifier aqueous solution]
20% DBS aqueous solution 1.0 part by mass ion-exchanged water 67.1 parts by mass
[Initiator aqueous solution-1]
8 mass% aqueous hydrogen peroxide solution 15.52 mass parts 8 mass% L (+)-ascorbic acid aqueous solution 15.52 mass parts
[Initiator aqueous solution-2]
8 mass% L (+)-ascorbic acid aqueous solution 14.21 mass parts It cooled after completion | finish of a polymerization reaction, and milky-white polymer primary particle emulsion B1 was obtained. The volume average particle diameter (mv) measured using Microtrac UPA was 0.28 μm, and the solid content concentration was 20.3% by mass.

<Production of polymer primary particle emulsion B2>
A reactor equipped with a stirrer (three blades), a heating / cooling device, and each raw material / auxiliary charging device was charged with 1.72 parts by weight of 20% DBS aqueous solution and 309 parts by weight of ion-exchanged water, and 90% under nitrogen flow The temperature was raised to ° C. <Initiator aqueous solution-3> in Table 2 was added all at once while stirring at a peripheral speed of 2.78 m / s at the tip of the stirring blade.

  Thereafter, with continued stirring, a mixture of <polymerizable monomers etc.> and <emulsifier aqueous solution> in Table 2 was added over 5 hours. Moreover, the time which started dripping the said mixture was made into "polymerization start", and <initiator aqueous solution-4> was added over 6 hours from the polymerization start in parallel with said operation. Stirring was further continued after the addition of <Initiator aqueous solution-4>, and the internal temperature was maintained at 90 ° C. for 1 hour.

[Table 2]
[Polymerizable monomers, etc.]
Styrene 88.0 parts by mass Butyl acrylate 12.0 parts by mass Acrylic acid 1.5 parts by mass Hexanediol diacrylate 0.4 parts by mass Trichlorobromomethane 0.48 parts by mass
[Emulsifier aqueous solution]
20% DBS aqueous solution 1.5 parts by mass ion-exchanged water 66.4 parts by mass
[Initiator aqueous solution-3]
8 mass% hydrogen peroxide aqueous solution 3.2 mass parts 8 mass% L (+)-ascorbic acid aqueous solution 3.2 mass parts
[Initiator aqueous solution-4]
8% by mass aqueous hydrogen peroxide solution 18.9 parts by mass 8% by mass L (+)-ascorbic acid aqueous solution 18.9 parts by mass

  After completion of the polymerization reaction, the mixture was cooled to obtain a milky white polymer primary particle emulsion B2. The volume average particle diameter (mv) measured using Microtrac UPA was 0.14 μm, and the solid content concentration was 18.9% by mass.

<Manufacture of toner particle dispersion>
Using each component of Table 3, the following aggregation process (core material aggregation process / shell coating process) / circularization process was performed to obtain a dispersion of toner particles having a core-shell structure.

[Table 3]
Polymer primary particle emulsion B1 90 parts by weight of polymer primary particle emulsion B2 as solids 10 parts by weight of colorant (Pigment Yellow 74) dispersion as solids 6.7 parts by weight of 20% DBS aqueous solution as solids of colorant Core material aggregation In the process, the solid content is 0.1 parts by mass
In the rounding step, the solid content is 4 parts by mass, 0.5% by mass aluminum sulfate aqueous solution, and the solid content is 0.1 parts by mass.

○ Core material agglomeration process Polymer primary particle emulsion B1 and 20% DBS aqueous solution are charged into a mixer equipped with a stirrer (double helical blade), heating / cooling device, and raw material / auxiliary charging device, and stirred at an internal temperature of 10 ° C. The mixture was stirred for 5 minutes at a peripheral speed of 0.8 m / s at the blade tip. Subsequently, the peripheral speed of the tip of the stirring blade was increased to 5.1 m / s, and the colorant dispersion was continuously added over 8 minutes and held for 5 minutes, and then an aluminum sulfate 0.5 mass% aqueous solution and ion-exchanged water 1 .5 parts by mass was continuously added over a total of 12 minutes and then held for 5 minutes.
Thereafter, the internal temperature was raised to 54 ° C. over 96 minutes while maintaining the peripheral speed. Next, the state was maintained for 117 minutes, and the volume median diameter (Dv50) was measured using a multisizer. As a result, it grew to 7.4 μm.

-Shell coating process Then, polymer primary particle emulsion B2 was continuously added over 20 minutes, and was kept as it was for 40 minutes. At this time, the Dv50 of the particles was 7.9 μm.

○ Circularization Step Subsequently, a 20% DBS aqueous solution and 1.4 parts by mass of ion-exchanged water were added over a total of 15 minutes, and then the temperature was raised to 99 ° C. and then held for 60 minutes. Thereafter, the mixture was cooled to 30 ° C. over 90 minutes to obtain a toner particle dispersion. At this time, the Dv50 of the toner particles was 7.7 μm, and the average circularity measured using a flow particle image analyzer FPIA-2100 (manufactured by Sysmex Corporation) was 0.960.

<Washing of toner particles>
The toner particle dispersion is produced a plurality of times by the above method, and the toner particle dispersion for one time is filtered using a filter press (ISD Raster filter: manufactured by Ishigaki) equipped with the filter described in Table 4, and further toner particles In contrast, the operation of passing 70 times ion-exchanged water and washing, and then pressing and discharging was repeated.

[Table 4]
[Filter used in the filter press]
Material: Polypropylene texture: 5 sheets satin weave Thickness: 0.75mm
Air permeability: 30 ml / cm ² · min
As shown in FIG. 1, the filter water flow rate for each elapsed time was measured. The manufactured toner particle dispersion is solid-liquid separated with a filter, and the time Tn required for a predetermined amount of ion-exchanged water to pass through the filter is 2 of the time T1 required when a new filter is used. The state of the filter at the time when it becomes twice or more is defined as the filter usage limit due to clogging, and the regeneration process is performed on the filter that has reached the usage limit.

In the regeneration process, when the toner particle cake is discharged, the toner particles adhering to the filter are washed off with water at room temperature using a hose, the filter is closed again, and then heated to 90 ° C. in the filter press. It was performed by passing ion-exchanged water. The wax particles that are the main cause of clogging are melted by the heat of the ion-exchanged water, so that the flow rate during water flow is the same as when using a new filter (equivalent to the equivalent water supply amount). Of water flow). The recovery process was completed with the recovery of the flow rate. The total hot water flow time was 45 minutes. After the filter regeneration, the above-described cleaning was repeated, and eight cleanings were possible until the next use limit was reached. Since the new filter was used 9 times, it was possible to regenerate to almost the same level.

(Example 2)
The filter regeneration process was performed in exactly the same manner as in Example 1 except that the temperature of the ion exchange water during the filter regeneration process was 80 ° C. The time required for the flow rate to recover was 55 minutes, which was longer than in Example 1. However, the flow rate of the filter recovered to the same level as when a new filter was used, and it was 8 times until the filter usage limit was reached after regeneration. It was possible to wash.

(Example 3)
The filter was regenerated using a commercially available steam washer (Condor Super Steam Jet SP-100: discharge temperature 97 ° C.). The filter is hung, lightly applied to the surface of the filter (the surface that has kept contact with the toner particles) with the wiper nozzle attached to the tip, and water vapor is transferred while moving from top to bottom at a speed of about 1200 cm ² / min. Supplied. The flow rate of the filter recovered to the same level as when a new filter was used, and it was possible to perform washing for 7 times after the regeneration until the filter usage limit was reached.

(Comparative Example 1)
The filter regeneration process was performed in exactly the same manner as in Example 1, except that the temperature of water used for cleaning the filter was set to 65 ° C. The flow rate during water flow recovered to 80% of that when a new filter was used, but the filter reached its use limit after four washing cycles.

(Comparative Example 2)
The filter regeneration process was performed in exactly the same manner as in Example 1 except that the temperature of water used for cleaning the filter was 40 ° C. with respect to the above example. The flow rate during water flow recovered only to 60% of that when using a new filter. The filter reached the limit of use after one wash.
(Comparative Example 3)
The filter was washed by applying ion-exchanged water having a temperature of 20 ° C. to the filter using a high-pressure jetter. In the subsequent cleaning of the toner particles, the time required to pass the predetermined ion-exchanged water recovered to 1.2 times that required when using a new filter. There was a problem that the dispersion liquid leaked out from there.

    Tn Repeat nth cleaning time

Claims (4)

  In the production process of the electrostatic charge image developing toner, the toner particles obtained by polymerization are solid-liquid separated by a filter, and then the filter is washed at a temperature equal to or higher than the melting point of the wax contained in the toner particles. A method for regenerating a filter for toner solid-liquid separation.   The method for regenerating a toner solid-liquid separation filter according to claim 1, wherein the washing is performed with hot water or steam.   The method for regenerating a toner solid-liquid separation filter according to claim 1 or 2, wherein the solid-liquid separation filter is formed of a cloth. A method for producing a toner for developing an electrostatic charge image, wherein the toner particles obtained by polymerization are subjected to solid-liquid separation using the regenerated filter according to any one of claims 1 to 3.

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