JP2014018745A - Kneading emulsification dispersion method for kneading target material, and kneading machine for kneading target material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a kneading emulsification dispersion method for a kneading target material and a kneading machine for a kneading target material, with which particles in the kneading target material after kneading process have a smaller particle size than particles in the kneading target material before the kneading process.SOLUTION: A kneading emulsification dispersion method for a kneading target material includes a kneading process step of charging the kneading target material containing binding resin into a kneading machine, and kneading the kneading target material while heating it in the kneading machine. The kneading process step includes charging a dispersing medium into the kneading machine.

Description

  The present invention relates to a kneading and emulsifying dispersion method for a material to be kneaded and a kneading machine for the material to be kneaded.

  A method of visualizing image information through an electrostatic charge image such as electrophotography is currently used in various fields. In electrophotography, an electrostatic latent image is formed on an image carrier by a charging and exposure process (latent image forming process), and an electrostatic charge image developing toner (hereinafter sometimes simply referred to as “toner”). The electrostatic latent image is developed with a developer for developing an electrostatic charge image (hereinafter sometimes referred to simply as “developer”) (development process), and visualized through a transfer process and a fixing process.

  The electrostatic image developing toner can be obtained, for example, by the following manufacturing method.

  For example, Patent Document 1 discloses a process in which a toner material mixture (a material to be kneaded) containing a binder resin and a colorant is charged into a kneader and melt-kneaded while being heated and pressurized in the kneader, and the kneaded toner material mixture. A method for producing a toner for developing an electrostatic charge image comprising the steps of adding an emulsifier, kneading while heating and pressing in a kneader, and emulsifying and dispersing the toner material mixture to form particles of the toner material mixture is described. Has been.

JP 2010-122687 A

  The object of the present invention is to reduce the particle size of the binder resin, which is the material to be kneaded before the kneading treatment, and the colorant particles contained therein by kneading treatment, and to make the particle size distribution unimodal. An object of the present invention is to provide a kneading and emulsifying dispersion method and a kneading machine for a material to be kneaded.

  The invention according to claim 1 includes a kneading treatment step in which a material to be kneaded containing a binder resin is charged into a kneader and the material to be kneaded is kneaded while being heated in the kneader. This is a method for kneading, emulsifying and dispersing a material to be kneaded, in which a dispersion medium is put into a kneader.

  The invention according to claim 2 is the method for kneading, emulsifying and dispersing the material to be kneaded according to claim 1, wherein the softening point of the dispersion medium is higher than the melting point of the binder resin.

  According to a third aspect of the present invention, there is provided a dispersion medium, a material to be kneaded containing a binder resin, a kneading container into which the dispersion medium is charged, a stirring member provided in the kneading container, and heating the material to be kneaded. A kneading machine for an object to be kneaded, comprising heating means for performing the above.

  According to the first aspect of the present invention, compared to the case without this configuration, the binder resin that is the material to be kneaded before the kneading process and the colorant particles contained therein are reduced in size by the kneading process. In addition, a method for kneading, emulsifying and dispersing a material to be kneaded having a unimodal particle size distribution is provided.

  According to the second aspect of the present invention, the binder resin, which is the material to be kneaded before the kneading process, and the colorant particles contained therein are reduced in size by the kneading process as compared with the case without this configuration. In addition, there is provided a method for kneading, emulsifying and dispersing a material to be kneaded, which makes the particle size distribution unimodal and further suppresses the spread of the particle size distribution.

  According to the invention of claim 3, compared to the case without this configuration, the binder resin that is the material to be kneaded before the kneading process and the colorant particles contained therein are reduced in size by the kneading process. In addition, a kneading machine for a material to be kneaded having a unimodal particle size distribution is provided.

It is a schematic structure figure showing an example of a kneading machine concerning an embodiment of the present invention. FIG. 2 is a schematic top view of the kneader in FIG. 1.

  Embodiments of the present invention will be described below. This embodiment is an example for carrying out the present invention, and the present invention is not limited to this embodiment.

  The present embodiment includes a kneading treatment step in which a material to be kneaded including a binder resin is charged into a kneader described below and kneaded with the material to be kneaded while being heated in the kneader. A dispersion medium described below (hereinafter sometimes referred to as a medium) is put into the kneader. That is, in the kneading process, the material to be kneaded and the medium are mixed in the kneader.

  FIG. 1 is a schematic configuration diagram illustrating an example of a kneader according to an embodiment of the present invention, and FIG. 2 is a schematic top view of the kneader of FIG. As shown in FIGS. 1 and 2, a kneading machine 1 for a material to be kneaded according to this embodiment is provided in a kneading container 10 into which a material to be kneaded including a binder resin and a medium are charged, and the kneading container 10. A stirrer 12 as a stirring means including the stirring member 22 and a heating jacket 14 as a heating means for heating the material to be kneaded are provided. At the top of the kneading vessel 10, a charging port 16 is provided. The stirrer 12 of this embodiment includes a motor 18 as a driving unit, a rotating shaft 20, and a stirring member 22 installed on the rotating shaft 20, and the stirring member 22 is rotated around the rotating shaft 20 by the motor 18. The stirring member 22 of the present embodiment includes two screw-shaped stirring blades, and the two stirring blades are arranged to face each other. The shape of the stirring member 22 is not limited to a screw shape, and may be a stirring blade such as a blade shape. Further, the number of stirring blades is not particularly limited. The heating jacket 14 may be installed on at least a part of the outer peripheral side surface of the kneading container 10, but is preferably installed on the entire outer peripheral side surface of the kneading container 10. The heating jacket 14 has a space through which the heating medium passes, and the material to be kneaded in the kneading container 10 is heated via the kneading container 10 when the heating medium passes through the inner space. The

  A kneading machine 1 for a material to be kneaded shown in FIG. 1 is a heating type in which a material to be kneaded is put into a kneading container 10 when kneading, and is kneaded while being heated. It is a batch type kneader. And as a kneading machine used for the kneading emulsification dispersion method of the material to be kneaded of this embodiment, it is preferable to use a batch type kneader as shown in FIG. For example, a single screw extruder, a twin screw extruder, a pressure kneader, a double-arm kneader, a Banbury mixer, a Brabender mixer, or the like may be used.

  The kneading and emulsifying and dispersing method for a material to be kneaded according to the present embodiment will be described using the kneading machine 1 for the material to be kneaded in FIG.

  The material to be kneaded and the medium containing the binder resin are charged into the kneading container 10 from the charging port 16. In addition, the material to be kneaded is heated via the kneading vessel 10 by the heating jacket 14, and the material to be kneaded and the medium are stirred by the stirring member 22 to perform the kneading process of the material to be kneaded (kneading process step). The heating temperature of the material to be kneaded is preferably higher than the melting point of the binder resin.

  In the present embodiment, when the material to be kneaded containing the binder resin is kneaded, the medium also flows in the kneading container 10 together with the material to be kneaded containing the binder resin. It is considered that the energy for dispersing the material to be kneaded including the resin is increased. In the present embodiment, when the material to be kneaded containing the binder resin is kneaded, the binder resin that is the material to be kneaded and the colorant particles contained therein are stirred (or pulverized) by the stirring member 22. It is considered that the agitation and pulverization are also performed by the medium flowing in the kneading vessel 10. As a result, the kneaded material after the kneading process of the present embodiment is reduced in particle size by the kneading process, and for example, it is easier to reduce the particle size than the kneaded product kneaded only by stirring with the stirring member 22 without introducing the media. Become. Moreover, it becomes easy to make the particle size distribution unimodal. The volume average particle size after the kneading treatment of the present embodiment is preferably in the range of 0.05 μm to 0.5 μm, for example, and more preferably in the range of 0.1 μm to 0.3 μm.

  When preparing a binder resin emulsified dispersion using the kneading emulsification dispersion processing method of the present embodiment, for example, a binder resin and media as a material to be kneaded are charged into the kneading container 10 from the inlet 16 and mixed. The material to be kneaded is kneaded while being heated inside. Then, during or after the kneading treatment, for example, a basic substance (pH adjuster) such as a surfactant, pure water, sodium hydroxide or the like may be added to obtain a binder resin fraction emulsified dispersion. .

  Further, when an electrostatic charge image developing toner is prepared using the kneading and emulsifying dispersion processing method of the present embodiment, for example, a binder resin, a colorant added as necessary, other components such as a release agent, etc. The material to be kneaded and the medium containing the above are introduced into the kneading container 10 from the charging port 16, and the material to be kneaded is kneaded while being heated in the mixing container. After kneading treatment, for example, a known agglomeration step in which a basic substance (pH adjuster) such as surfactant, pure water, sodium hydroxide or the like is added to form a toner dispersion, and agglomerated particles are formed in the toner dispersion. The toner for developing an electrostatic image may be obtained through a known fusing process for fusing the agglomerated particles.

  In the preparation of the toner for developing an electrostatic image, it is preferable to use a kneaded product composed of particles having a small particle diameter in order to control the particle diameter of the aggregated particles and the internal structure in the aggregation process performed after the kneading process. Therefore, as described above, the volume average particle size of the particles in the kneaded product obtained by the kneading treatment method of the present embodiment is smaller than the volume average particle size of the particles in the material to be kneaded before the kneading process, Furthermore, since it is easy to make the particle diameter smaller than the volume average particle diameter of the kneaded material kneaded by only stirring by the stirring member 22 without introducing the medium, the kneaded material obtained by the kneading treatment method of the present embodiment is used. It is preferable to control the particle size of the agglomerated particles, control the internal structure, etc. in the agglomeration step performed after the kneading process.

  The dispersion medium (media) used in the present embodiment may be a solid material in which the binder resin as the material to be kneaded and the colorant particles contained therein are dispersed, but the material to be kneaded containing the binder resin. Preferably, it is made of a material that does not physically or chemically interfere with the material. The physical interference with the material to be kneaded including the binder resin means, for example, a case where the medium is melted and uniformed by heating during the kneading process. In addition, the chemical interference with the material to be kneaded containing the binder resin means, for example, a case of chemically reacting with the material to be kneaded containing the binder resin.

  The media used in the present embodiment is a binder resin from the viewpoint of avoiding physical interference with the material to be kneaded containing the binder resin, the point of suppressing the expansion of the particle size distribution of the particles in the kneaded material after the kneading process, and the like. It preferably has a softening point higher than the melting temperature. The melting temperature of the binder resin is measured using a differential scanning calorimeter (Seiko Denshi Kogyo Co., Ltd .: DSC-20) by measuring from room temperature (25 ° C.) to 150 ° C. under a temperature rising rate of 10 ° C./min. Desired. The softening point of the media was measured with a flow tester (manufactured by Shimadzu Corp .: CFT-500C), preheating: 80 ° C./300 sec, plunger pressure: 0.980665 MPa, die size: 1 mmφ × 1 mm, heating rate: 3 The intermediate temperature between the melting start temperature and the melting end temperature under the condition of 0.0 ° C./min. The medium preferably has a softening point higher than the melting temperature of the binder resin and does not have a melting temperature.

  The medium used in the present embodiment is preferably softer than the material on the inner surface of the stirring member or the kneading container from the viewpoint of suppressing damage to the medium. In general, for example, a gap may be provided between the inner surface of the kneading vessel 10 and the stirring member 22 so that the stirring member 22 and the inner surface of the kneading vessel 10 do not collide. If the average particle diameter of the media is larger than the gap between the inner surface of the kneading vessel 10 and the stirring member 22, the media may be pressed against the inner surface of the kneading vessel 10 by the stirring member 22 and may be damaged. However, when a medium softer than the material of the stirring member or the inner surface of the kneading container is used, it is considered that the pressure or the like pressed against the inner surface of the kneading container 10 by the stirring member 22 is alleviated, and damage to the medium is suppressed.

  Moreover, it is preferable that the media used in this embodiment have an average particle diameter smaller than the gap between the inner surface of the kneading vessel 10 and the stirring member 22. When a medium having an average particle diameter smaller than the gap provided between the inner surface of the kneading vessel 10 and the stirring member 22 is used, it is considered that the pressure or the like pressed against the inner surface of the kneading vessel 10 by the stirring member 22 is relieved. Further, damage to the media is suppressed as compared with the case where media having an average particle diameter larger than the gap provided between the inner surface of the kneading container 10 and the stirring member 22 is used.

  The material constituting the media used in this embodiment is made of glass, ceramic, metal oxides such as zirconia and alumina, and metals such as stainless steel in terms of avoiding chemical interference with the material to be kneaded including the binder resin. , Resins such as styrene, acrylonitrile, and butadiene. The resin is preferably a resin having a softening point higher than the melting point of the binder resin and a higher elastic modulus than that of glass, ceramic, metal oxide, metal, etc., for example, a styrene resin such as acrylonitrile styrene copolymer Examples include modified products.

  The shape of the media used in the present embodiment may be any shape such as a columnar shape or a prismatic shape.

  The electrostatic image developing toner prepared by using the kneading emulsification dispersion processing method of the present embodiment contains a binder resin, and if necessary, a colorant, a release agent, a charge control agent, inorganic particles. And other components.

  Examples of the binder resin constituting the electrostatic image developing toner include styrenes such as styrene, parachlorostyrene, and α-methylstyrene, methyl acrylate, ethyl acrylate, n-propyl acrylate, and n-butyl acrylate. (Meth) acrylic esters such as lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, acrylonitrile, methacrylonitrile, etc. Ethylenically unsaturated nitriles, vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether, vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl isopropenyl ketone, and polyolefins such as ethylene, propylene and butadiene. Polymers such as monomers such as fin acids, or a copolymer of a combination of two or more of these, or mixtures thereof. In addition, as the binder resin, for example, epoxy resin, polyester resin, polyurethane resin, polyamide resin, cellulose resin, polyether resin, etc., non-vinyl condensation resin, a mixture of these with the vinyl resin, and coexistence thereof Examples include graft polymers obtained by polymerizing vinyl monomers. These resins may be used alone or in combination of two or more.

  The binder resin may be a crystalline resin, an amorphous resin, or a combination of a crystalline resin and an amorphous resin.

  In the present embodiment, “crystallinity” of “crystalline resin” refers to having a clear endothermic peak rather than a stepwise endothermic amount change in differential scanning calorimetry (DSC) of the resin or toner. Specifically, in differential scanning calorimetry (DSC) using a differential scanning calorimeter (equipment name: DSC-60 type) manufactured by Shimadzu Corporation equipped with an automatic tangential processing system, a rate of temperature increase of 10 ° C./min. A “clear” endothermic peak is assumed when the temperature from the onset point to the top of the endothermic peak when the temperature is raised at 10 ° C. is within 10 ° C. The point of the flat part of the baseline in the DSC curve and the point of the flat part of the falling part from the base line are specified, and the intersection of the tangents of the flat part between the two points is set as an “onset point” by the automatic tangent processing system. Desired. Further, the endothermic peak may show a peak having a width of 40 ° C. or more and 50 ° C. or less when the toner is used.

  The term “amorphous resin” means that when the temperature from the onset point to the peak top of the endothermic peak exceeds 10 ° C. or a clear endothermic peak is observed in differential scanning calorimetry (DSC) of the resin or toner. It refers to a resin that cannot be used. Specifically, in differential scanning calorimetry (DSC) using a differential scanning calorimeter (equipment name: DSC-60 type) manufactured by Shimadzu Corporation equipped with an automatic tangential processing system, a rate of temperature increase of 10 ° C./min. When the temperature from the onset point to the peak top of the endothermic peak exceeds 10 ° C. or when no clear endothermic peak is observed, it is assumed to be “amorphous”. Further, the temperature from the onset point to the peak top of the endothermic peak preferably exceeds 12 ° C., and more preferably no clear endothermic peak is observed. The method for obtaining the “onset point” in the DSC curve is the same as in the case of the “crystalline resin”.

  The crystalline resin is not particularly limited as long as it is a resin having crystallinity, and specific examples include crystalline polyester resins and crystalline vinyl resins. Examples of the crystalline vinyl resin include amyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, and (meth) acrylic acid. Decyl, undecyl (meth) acrylate, tridecyl (meth) acrylate, myristyl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, oleyl (meth) acrylate, behenyl (meth) acrylate And vinyl resins using long-chain alkyl and alkenyl (meth) acrylic acid esters.

  The crystalline polyester resin is synthesized from a carboxylic acid (dicarboxylic acid) component and an alcohol (diol) component, and in this embodiment, the “carboxylic acid component” is an acid component before the synthesis of the polyester resin. The “alcohol component” refers to a component site that was an alcohol component before the synthesis of the polyester resin. In the case of a polymer obtained by copolymerizing other components with respect to the crystalline polyester main chain, when the other components are 50% by mass or less, this copolymer is also called a crystalline polyester resin.

  The colorant constituting the toner for developing an electrostatic image may be a dye or a pigment, but is preferably a pigment from the viewpoint of light resistance and water resistance. Examples of colorants include carbon black, aniline black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, and rose. Bengal, Quinacridone, Benzidine Yellow, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 57: 1, 185, C.I. I. Pigment red 122, C.I. I. Pigment red 185, C.I. I. Pigment red 238, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 74, C.I. I. Pigment blue 15: 1, C.I. I. A known pigment such as CI Pigment Blue 15: 3 is used. The form may be in the form of a powder dried as a product or in the form of a cake containing moisture during production.

  The release agent constituting the electrostatic image developing toner includes, for example, low molecular weight polyolefins such as polyethylene, polypropylene and polybutene, silicones having a softening point by heating, oleic acid amide, erucic acid amide, ricinoleic acid amide, stearin Fatty acid amides such as acid amides, plant waxes such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil, animal waxes such as beeswax, montan wax, ozokerite, ceresin, paraffin wax And minerals such as microcrystalline wax and Fischer-Tropsch wax, petroleum wax, and modified products thereof.

  These mold release agents can be used alone or in combination of two or more. The content of these release agents is preferably 1 part by mass or more and 10 parts by mass or less, and more preferably 5 parts by mass or more and 9 parts by mass or less with respect to 100 parts by mass of the binder resin.

  Examples of the charge control agent constituting the toner for developing an electrostatic image include azo metal complexes, metal complexes or metal salts of salicylic acid or alkylsalicylic acid.

  The inorganic particles constituting the electrostatic image developing toner are, for example, silica particles, titanium oxide particles, alumina particles, cerium oxide particles, or known inorganic particles such as those obtained by hydrophobizing the surface thereof, alone or in combination. However, silica particles having a refractive index smaller than that of the binder resin are preferable from the viewpoint of not impairing transparency such as color developability and overhead projector (OHP) transparency. Further, the silica particles may be subjected to various surface treatments, and for example, those subjected to surface treatment with a silane coupling agent, a titanium coupling agent, silicone oil or the like are preferable.

  Hereinafter, although an example and a comparative example are given and the present invention is explained more concretely in detail, the present invention is not limited to the following examples.

<Example 1>
(Preparation of binder resin dispersion)
The resin particle dispersion was prepared using the kneader shown in FIG. 1 (the gap between the inner surface of the kneading container and the stirring member was 3.0 mm). First, in a kneading container, 300 parts by mass of a polyester resin (melting point (Tm) of 105 ° C. or more and 109 ° C. or less) as a binder resin, a medium (particle diameter 2.5 mm, height 3 mm height) (Made by Asahi Kasei Chemicals Co., Ltd., which softens at 130 ° C. or higher but does not have a melting point) 50 parts by weight, 25 parts by weight of a surfactant are added, and the rotation speed of the stirring member is 50 rpm and the jacket temperature is 110 ° C. The mixture was heated and stirred for 60 minutes to soften the polyester resin (melt kneading step). The media was dispersed in the softened resin. Next, 6 parts by mass of an aqueous sodium hydroxide solution as a basic substance was added. Next, 600 parts by mass of pure water was gradually added while maintaining the temperature in the kneading vessel at 95 ° C. or higher. When the addition was completed, the mixture was emulsified and dispersed to obtain a binder resin aqueous dispersion. The obtained resin water dispersion had a volume average particle size of 115 nm and a particle size distribution that was unimodal. These results are summarized in Table 1.

  The volume average particle diameter was determined by measuring using Nanotrac UPA (Nikkiso Co., Ltd.). Specifically, the cumulative distribution is drawn from the small diameter side to the particle size range (channel) divided based on the particle size distribution of the resin water dispersion measured by Nanotrack UPA (manufactured by Nikkiso Co., Ltd.). In addition, the particle diameter of cumulative 16% was defined as volume D16v, the particle diameter of cumulative 50% was defined as volume D50v, the particle diameter of cumulative 84% was defined as volume D84v, and D50v was determined as the volume average particle diameter.

<Example 2>
(Adjustment of binder resin coloring dispersion)
First, in a kneading container, 270 parts by mass of a polyester resin as a binder resin (melting point (Tm) 105 ° C. or higher and 109 ° C. or lower), 15 parts by mass of a magenta pigment as a colorant, 15 parts by mass of a release agent, media (average particles) A columnar styrene-based resin modified product (made by Asahi Kasei Chemicals Corporation) having a diameter of 2.5 mm and a height of about 3 mm, which is softened at 130 ° C. or higher but does not have a melting point) is added 100 parts by mass and stirred. The mixture was heated and stirred for 30 minutes at a member rotation speed of 50 rpm and a jacket temperature of 110 ° C. to soften the mixture (melt kneading step). The media was dispersed in the softened mixture. Next, 25 parts by mass of a surfactant and 7.5 parts by mass of an aqueous potassium hydroxide solution as a basic substance were added. Next, 600 parts by mass of pure water was gradually added while maintaining the temperature in the kneading vessel at 95 ° C. or higher. Upon completion of the addition, a red colored dispersion was obtained. The obtained color dispersion had a volume average particle size of 164 nm and a unimodal particle size distribution. These results are summarized in Table 1.

<Example 3>
(Adjustment of binder resin coloring dispersion)
First, in a kneading container, 240 parts by mass of a polyester resin (melting point (Tm) 105 ° C. to 109 ° C.) as a binder resin, 60 parts by mass of a yellow pigment as a colorant, media (average particle diameter 2.5 mm, height) About 3 mm cylindrical modified styrenic resin (made by Asahi Kasei Chemicals Co., Ltd., which softens at 130 ° C. or higher but does not have a melting point), 100 parts by mass, stirring member rotation speed 50 rpm, jacket The mixture was heated and stirred at a temperature of 110 ° C. for 30 minutes to soften the mixture (melt kneading step). The media was dispersed in the softened mixture. Next, 25 parts by mass of a surfactant and 6.5 parts by mass of an aqueous potassium hydroxide solution as a basic substance were added. Next, 600 parts by mass of pure water was gradually added while maintaining the temperature in the kneading vessel at 95 ° C. or higher. A yellow colored dispersion was obtained upon completion of the addition. The obtained color dispersion had a volume average particle size of 140 nm and a unimodal particle size distribution. These results are summarized in Table 1.

<Example 4>
A binder resin dispersion was prepared in the same manner as in Example 1 except that a medium having a softening point of 80 ° C. (made by Asahi Kasei Chemicals Co., Ltd., a cylindrical styrenic resin modified product) was used. As a result, the volume average particle size of the binder resin dispersion was 285 nm, and the particle size distribution was unimodal. These results are summarized in Table 1.

<Comparative example>
A binder resin dispersion was prepared in the same manner as in Example 1 except that no media was added. As a result, although a binder resin dispersion was obtained, the volume average particle diameter of the binder resin dispersion was 825 nm, the particle size distribution was multimodal, and was wider than in each example. These results are summarized in Table 1.

  In Examples 1 to 4 in which the media was added during the kneading process, the volume average particle diameter of the particles after the kneading process (binder resin particles) was the same as in the comparative example in which no media was input during the kneading process. The particle size was made smaller than the volume average particle size of the treated particles (binder resin particles). The particle size distribution of the particles after the kneading treatment in Examples 1 to 4 in which the media was added during the kneading treatment was unimodal, but in particular, the media having a softening point higher than the melting temperature of the binder resin. In Examples 1 to 3 using the above, the spread of the particle size distribution was suppressed more than in Example 4 using a medium having a softening point lower than the melting temperature of the binder resin. Further, in Examples 1 to 3 using media having a softening point higher than the melting point of the binder resin, the media after the kneading treatment were visually observed. As a result, no deformation of the media was observed.

  DESCRIPTION OF SYMBOLS 1 Kneading machine of to-be-kneaded material, 10 Kneading container, 12 Stirrer, 14 Jacket for heating, 16 Inlet, 18 Motor, 20 Rotating shaft, 22 Stirring member.

Claims (3)

A kneading step of charging a kneaded material containing a binder resin into a kneader and kneading the kneaded material while heating in the kneader;
In the melt-kneading step, a dispersion medium is introduced into the kneader.   The method for kneading and emulsifying and dispersing a material to be kneaded according to claim 1, wherein the softening point of the dispersion medium is higher than the melting point of the binder resin. A dispersion medium;
A kneaded container containing a binder to be kneaded and the dispersion medium;
A stirring member provided in the kneading vessel;
And a heating means for heating the material to be kneaded.

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