JP6622580B2 - Toner external additive - Google Patents

Description

  The present invention relates to a toner external additive.

  Toners used in developers used in electrophotographic machines, copying machines, printers, and the like are added with external additives to improve toner particle fluidity, chargeability, photosensitive drum cleaning properties, and the like. Yes.

  As such external additives, inorganic particles using an inorganic material and organic particles using an organic material are known. As the inorganic particles, those made of an inorganic material such as silica, titania or alumina are used. However, since the inorganic particles themselves are too hard, the problem that the inorganic particles existing on the surface of the toner particles are easily embedded in the toner particles due to contact or collision between the toner particles, and the effect as an external additive is hardly exhibited. was there.

  On the other hand, organic particles made of resin or the like can be controlled in terms of hardness and strength, so that problems such as those in the case of inorganic particles are unlikely to occur, and there is an advantage that an effect as an external additive can be easily expressed. As toner external additives composed of such organic particles, Patent Documents 1 to 3 describe organic particles composed of (meth) acrylic polymers.

JP 2011-173965 A International Publication No. 2014/157464 JP 2012-201862 A

  However, the organic particles described in Patent Documents 1 to 3 sometimes have insufficient dispersibility. Further, when added to the toner, the adhesion to the toner surface may not be sufficient, or the slipperiness (fluidity) of the toner surface may not be sufficiently improved. The present invention has been made in view of such circumstances, and is excellent in dispersibility, has good adhesion to the toner when added to the toner, and has slipperiness (fluidity) on the toner surface. It is an object of the present invention to provide an excellent toner external additive.

  The inventors of the present invention have made extensive studies in order to solve the above-described problems, and after configuring the toner external additive with a polymer having a structural unit derived from a specific monomer, the particle diameter is in a specific range, Further, when the particle size distribution is narrowed, the dispersibility is improved, the adhesion to the toner is improved when added to the toner, and the slipping property (fluidity) is improved. Was completed.

That is, the toner external additive according to the present invention is composed of a polymer containing 10% by mass or more and 50% by mass or less of a crosslinkable monomer unit having two or more ethylenic double bonds in one molecule. The volume average particle size is 5 nm or more and 100 nm or less, and the variation coefficient of the particle size is 30% or less.
The crosslinkable monomer is preferably an aromatic crosslinkable monomer.
The toner external additive preferably has an alkyl (meth) acrylate monomer unit.

1 part by mass of the toner external additive and 100 parts by mass of spherical test particles having a volume average particle diameter of 5 μm are mixed for 2 minutes at a rotational speed of 20,000 rpm at room temperature, and the toner external additive is mixed with the spherical test particles. When the adhesion test is performed, the adhesion dispersibility index calculated based on the following formula is preferably 5% or more.
Adhesive dispersibility index (%) = independent fine particle density (number / μm ² ) / maximum theoretical particle number (number / μm ² ) × 100
However, the density of the independent fine particles refers to the amount of toner particles adhering to the surface of the spherical test particle when the surface of the spherical test particle after the adhesion test is observed with a scanning electron microscope at a magnification of 15,000 to 20,000 times. This represents the number density of the additive, and when two or more toner external additives are adhered to each other, the adhered toner external additives are counted as one.
The maximum number of theoretical particles (number / μm ² ) is a value determined by the following formula.
Maximum number of theoretical particles present (number / μm ² ) = 0.9 / {(π / 4) × square of volume average particle diameter (μm) of toner external additive}

A toner composition containing toner particles and the toner external additive is also included in the technical scope of the present invention.
Hereinafter, a structural unit derived from a monomer may be simply referred to as a “monomer unit”.

  The toner external additive according to the present invention has structural units derived from a specific monomer at a predetermined ratio, the particle diameter is in a specific range, and the coefficient of variation of the particle diameter is suppressed to be low. Aggregation is suppressed, and even when agglomerated, it is easy to loosen the particles and the dispersibility is good. When added to the toner, the adhesion to the toner becomes good and the toner surface can be uniformly coated. As a result, the slipperiness (fluidity) of the toner is improved.

1 is a scanning electron microscope image of the composite particles obtained in Experimental Example 1. FIG.

1. Toner External Additive The toner external additive of the present invention is composed of a polymer containing 10% by mass or more and 50% by mass or less of a crosslinkable monomer unit having two or more ethylenic double bonds in one molecule. Is done. Therefore, the dispersibility of the toner external additive is easily improved. The volume average particle diameter is 5 nm or more and 100 nm or less, and the coefficient of variation of the particle diameter is 30% or less. Therefore, the dispersibility is good, the adhesion to the toner, and the fluidity of the toner (aggregate) provided with the toner external additive on the surface is good.

By including a structural unit derived from a monomer having two or more ethylenic double bonds in one molecule (hereinafter sometimes referred to as “crosslinkable monomer”), it becomes easy to improve the dispersibility of the toner external additive. .
Examples of the crosslinkable monomer include allyl (meth) acrylates such as allyl (meth) acrylate; ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate; 1,4-butanediol di (meth) acrylate, neopentyl Glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 3-methyl-1,5-pentanediol di (meth) acrylate, 1,8-octanediol di (meth) acrylate, 1,9 -Nonanediol di (meth) acrylate, 2,4-diethyl-1,5-pentanediol di (meth) acrylate, butylethylpropanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, 3 -Methyl-1,7-octanedioe Alkanediol di (meta) such as di (meth) acrylate, 2-methyl-1,8-octanediol di (meth) acrylate, 1,12-dodecanediol di (meth) acrylate, 1,3-butylene (meth) acrylate ) Acrylate; polyalkylene glycol di (meth) acrylate such as polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate (the number of repeating alkylene glycol units is, for example, 2 To 150); heteroatom-containing crosslinking monomers such as N, N-divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfonic acid; divinylbenzene, divinylnaphthalene, divinyltoluene, 4,4′-divinyl Aromatic crosslinkable monomers such as phenyl and derivatives thereof; three or more (meth) acrylic acids such as trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate and dipentaerythritol hexa (meth) acrylate And the like, and the like.

  Among these, monomers having 2 to 4 ethylenic double bonds are preferable, monomers having 2 to 3 ethylenic double bonds are more preferable, and monomers having 2 ethylenic double bonds are more preferable.

The ratio of the crosslinkable monomer unit is preferably 5% by mass or more, more preferably 10% by mass or more, and preferably 50% by mass or less, in the polymer constituting the toner external additive. Is 40% by mass or less, more preferably 35% by mass or less, and particularly preferably 30% by mass or less. The greater the proportion of the crosslinkable monomer unit, the better the slipperiness (fluidity) when the toner external additive is added to the toner surface.
In this specification, the ratio of each monomer unit in the polymer can be approximated to the ratio of each monomer in the total amount of raw material monomers, and in this specification, the numerical values described for the ratio of each monomer in the total amount of raw material monomers are These can be applied to the ratio of each monomer unit in the polymer.

  Moreover, it is preferable that a crosslinkable monomer contains the aromatic crosslinkable monomer which has an aromatic ring and two or more ethylenic double bonds in 1 molecule. Therefore, in the polymer constituting the toner external additive of the present invention, the ratio of the aromatic crosslinkable monomer unit is preferably 90% by mass or more, more preferably 95% by mass or more in the crosslinkable monomer unit. More preferably, it is 98% by mass or more, and particularly preferably 100% by mass. When the ratio of the aromatic crosslinkable monomer unit is large, the dispersibility of the obtained toner external additive is further improved.

  It is preferable that the toner external additive further has an alkyl (meth) acrylate monomer unit. As the alkyl (meth) acrylate monomer, an alkyl (meth) acrylate monomer in which the alkyl group has 1 to 4 carbon atoms (preferably 1 to 3 carbon atoms) is preferable. Specific examples of the alkyl (meth) acrylate monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, and pentyl (meth) ) Acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, 2-ethylhexyl (meth) ) Alkyl (meth) acrylates such as acrylate.

  The alkyl (meth) acrylate monomer unit is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 65% by mass or more, particularly preferably in the polymer constituting the toner external additive. It is 70 mass% or more, it is preferable that it is 95 mass% or less, More preferably, it is 90 mass% or less.

The toner external additive of the present invention may contain a structural unit derived from a monomer other than the crosslinkable monomer and the alkyl (meth) acrylate monomer.
As said other monomer, the monomer containing one ethylenic double bond is mentioned, (meth) acrylic acid; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl ( Hydroxy group-containing (meth) acrylic monomers such as (meth) acrylate; alkoxy group-containing (meth) acrylic such as 2-methoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate and 2-butoxyethyl (meth) acrylate Monomers: Epoxy group-containing (meth) acrylic monomers such as glycidyl (meth) acrylate; cyclopropyl (meth) acrylate, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, cyclooctyl (meth) acrylate, cycloounde (Meth) acrylate, cyclododecyl (meth) acrylate, isobornyl (meth) acrylate, cycloalkyl (meth) acrylate such as 4-t-butylcyclohexyl (meth) acrylate; 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, etc. Hydroxyl group-containing vinyl ethers; hydroxyl group-containing allyl ethers such as 2-hydroxyethyl allyl ether and 4-hydroxybutyl allyl ether; styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, α-methyl styrene, ethyl vinyl benzene Aromatic vinyl such as p-methoxystyrene, p-tert-butylstyrene, p-phenylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, p-hydroxystyrene Monomers; aromatic ring-containing monofunctional (meth) acrylic monomers such as phenyl (meth) acrylate, benzyl (meth) acrylate, tolyl (meth) acrylate, and phenethyl (meth) acrylate;

  The proportion of the structural unit derived from the other monomer is 60% by mass or less, preferably 50% by mass or less, more preferably 40% by mass or less, in the polymer constituting the toner external additive. More preferably, it is 30 mass% or less, More preferably, it is 20 mass% or less, It is especially preferable that it is 10 mass% or less. The proportion of structural units derived from (meth) acrylic acid is preferably 1% by mass or less, more preferably less than 0.1% by mass, and still more preferably in the polymer constituting the toner external additive. It is 0.07 mass% or less.

The ratio of the polymer having a structural unit derived from each monomer is preferably 90% by mass or more, and more preferably 95% by mass or more in the toner external additive.
In addition, the content of the basic substance in the toner external additive of the present invention is preferably 0.3% by mass or less, and more preferably 0.1% by mass or less.
Examples of the basic substance include amines such as ammonia, monoethanolamine, diethanolamine, triethanolamine, methylamine, dimethylamine, ethylamine, diethylamine, trimethylamine, and triethylamine; alkali metal hydroxides; alkali metal alkoxides, and the like. It is done.

  The toner external additive of the present invention is composed of the above polymer, and has a volume average particle size of 5 nm or more and 100 nm or less, and a coefficient of variation (CV value) of particle size of 30% or less. Therefore, the dispersibility is good. Furthermore, when added to the toner, the adhesion to the toner, and the slipperiness (fluidity) of the toner are improved.

The volume average particle diameter of the toner external additive is 5 nm or more, preferably 10 nm or more, more preferably 20 nm or more, 200 nm or less, preferably 100 nm or less, more preferably 80 nm or less.
Furthermore, the coefficient of variation (CV value) of the particle diameter is 30% or less, preferably 25% or less, more preferably 20% or less, still more preferably 17% or less, and 0%. Most preferably, it may be, for example, 3% or more, further 5% or more.
The variation coefficient (CV value) of the particle diameter of the toner external additive is a value obtained by applying the volume average particle diameter of the toner external additive and the standard deviation of the particle diameter of the toner external additive to the following formula. .
Coefficient of variation of particle diameter (%) = 100 × (standard deviation of particle diameter / number average particle diameter)

  The volume average particle diameter can be determined by measurement using a light scattering particle size distribution analyzer (for example, “Nicomp MODEL 380” manufactured by Particle Sizing Systems).

The toner external additive of the present invention has a structural unit derived from the above monomer, has a particle diameter in a predetermined range, and has a narrow particle diameter distribution (because the coefficient of variation is suppressed). And fluidity is good. The dispersibility of the toner external additive can be evaluated by, for example, an adhesion dispersibility index (%). The adhesion dispersibility index (%) is obtained by using 1 part by mass of the toner external additive and 100 parts by mass of spherical test particles having a volume average particle diameter of 5 μm at a rotational speed of 20,000 rpm at room temperature (eg, 20 to 30 ° C.) It means a value calculated on the basis of the following formula when a test is performed in which the toner external additive is adhered to the spherical test particles by mixing for 2 minutes.
Adhesive dispersibility index (%) = independent fine particle density (number / μm ² ) / maximum theoretical particle number (number / μm ² ) × 100
However, the density of the independent fine particles refers to the amount of toner particles adhering to the spherical test particle surface when the surface of the spherical test particle after the adhesion test is observed with a scanning electron microscope at a magnification of 10,000 to 20,000 times. This represents the number density of the additive, and when two or more toner external additives are adhered to each other, the adhered toner external additives are counted as one.
The maximum theoretical particle existence number (pieces / μm ² ) assumed that all toner external additives have the same particle diameter as the average particle diameter, exist in one layer without any gap and do not stick to each other. It expresses the maximum number density at the time and is a value obtained by the following formula.
Maximum number of theoretical particles present (number / μm ² ) = 0.9 / {(π / 4) × square of volume average particle diameter (μm) of toner external additive}

  The adhesion dispersibility index (%) is preferably 5% or more, more preferably 6% or more, for example, 50% or less, further 20% or less, and particularly 10% or less.

  The spherical test particles may be composed of any of metals (particularly silicon iron) and resins.

  The toner external additive of the present invention is a dry powder, and the water content contained in the toner external additive is preferably 5% or less, more preferably 3% or less, and still more preferably 1%. For example, it is 0.1% or more, and may be 0.5% or more. In order to make the toner external additive into a dry powder, for example, spray drying may be performed with a spray dryer having an outlet temperature of 75 ° C. or higher (preferably 80 ° C. or higher).

  The shape of the toner external additive may be, for example, spherical, spheroid, confetti, thin plate, needle, or eyebrow, and is preferably spherical. Further, the shape of the particle surface may be any of a smooth shape, a bowl shape and a porous shape, and a smooth shape is preferred.

  The toner external additive of the present invention polymerizes the crosslinkable monomer and the alkyl (meth) acrylate monomer and other various monomers (hereinafter sometimes referred to as “monomer component”) used as necessary. Can be obtained. Examples of the polymerization method include suspension polymerization, emulsion polymerization, and dispersion polymerization. Among these, emulsion polymerization in which the monomer component is dispersed in a reaction solvent in the presence of an emulsifier (radical) polymerization reaction is preferable.

The emulsifier is preferably an anionic emulsifier from the viewpoint of dispersion stability.
As an anionic emulsifier, 1 type (s) or 2 or more types can be used, fatty acid oils such as sodium oleate and castor oil potassium; alkyl sulfate salts such as sodium lauryl sulfate and ammonium lauryl sulfate; polyoxyethylene distyryl phenyl ether sulfate Ammonium salt, polyoxyethylene distyryl phenyl ether sulfate sodium salt such as polyoxyethylene distyryl phenyl ether sulfate sodium salt; alkyl benzene sulfonate such as sodium dodecylbenzene sulfonate; alkyl naphthalene sulfonate, alkane sulfonate, Dialkyl sulfosuccinate, alkyl phosphate ester salt, naphthalene sulfonic acid formalin condensate, polyoxyethylene alkylphenyl ether sulfate ester, Shi ethylene alkyl sulfates, and the like. Among them, alkylbenzene sulfonic acid salts are preferred.

  The emulsifier is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, still more preferably 0.3 parts by mass or more, particularly preferably based on 100 parts by mass of the total of the monomer components. Is 0.5 parts by mass or more, preferably 2 parts by mass or less, more preferably 1.5 parts by mass or less, and still more preferably 1 part by mass or less.

  Examples of the reaction solvent include water; organic solvents (particularly hydrophilic organic solvents) such as alcohols and ketones, and water or a mixed solvent of water and an organic solvent is preferable. The reaction solvent is usually used in a range of 100 parts by mass or more with respect to 100 parts by mass of the monomer composition, preferably 500 parts by mass or more, more preferably 700 parts by mass or more, and further preferably 800 parts by mass or more. Yes, 1900 parts by mass or less is preferable.

  The addition mode of the monomer component in the reaction system is not particularly limited, and the mode in which the entire amount is charged into the reaction vessel at once before the addition of the polymerization initiator; after the polymerization of a part of the monomer composition Various aspects are adopted, such as an aspect in which the remainder is added to the reaction system at once or in a divided manner; an aspect in which the monomer composition is continuously added to the reaction system at a constant rate; be able to. From the viewpoint of preventing the formation of a coarse polymer, an embodiment in which a part of the monomer composition is polymerized and then the remainder is added into the reaction system (once or continuously) is preferable. In this case, it is preferable to add the remainder while maintaining the polymerization temperature after the polymerization of a part of the monomer composition is started and before the polymerization is completed. This facilitates narrowing the particle size distribution of the toner external additive, and at the same time, the toner external additive has a single layer structure. The layer structure of the toner external additive can be confirmed by observing the cross section with a scanning electron microscope.

  When polymerizing the monomer component, for example, means such as a polymerization initiator, irradiation of ultraviolet rays or radiation, application of heat, etc. are used, it is preferable to use a polymerization initiator, the dispersibility of the monomer component From this point of view, it is preferable to use a redox polymerization initiator which is a combination of an oxidizing agent and a reducing agent.

  As said oxidizing agent, 1 type (s) or 2 or more types can be used, for example, hydrogen peroxide; persulfates, such as potassium persulfate, ammonium persulfate, and sodium persulfate; Hydroperoxide, cumene hydroperoxide, p-menthane hydroperoxide, diisopropylbenzene peroxide, 1,1,3,3-tetramethyl hydroperoxide, 2,4,4-trimethylpentyl-2-hydroperoxide, etc. And organic peroxides such as methyl peroxides such as methyl ethyl ketone peroxide, cyclohexanone peroxide, and acetyl ketone peroxide.

  As a reducing agent, 1 type (s) or 2 or more types can be used, for example, ascorbic acid, sodium ascorbate, ascorbates such as potassium ascorbate; erythorbates such as erythorbic acid, sodium erythorbate, potassium erythorbate Tartrate salts such as tartaric acid and sodium tartrate and potassium tartrate; phosphites such as phosphorous acid and sodium phosphite and potassium phosphite; hydrogen phosphites such as sodium hydrogen phosphite and potassium hydrogen phosphite; sodium sulfite and potassium sulfite Bisulfites such as sodium bisulfite and potassium bisulfite; thiosulfates such as sodium thiosulfate and potassium thiosulfate; thiosulfites such as sodium thiosulfite and potassium thiosulfite; Pyrosulfites such as potassium pyrosulfite; Pyrosulfites such as sodium hydrogen bisulfite and potassium hydrogen bisulfite; Pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate; Sodium hydroxymethanesulfonate (sodium formaldehyde sulfoxylate) ) And the like. If necessary, a sulfate or chloride salt of heavy metal such as iron, nickel, chromium, molybdenum, or cerium may be used in combination as an activator of the redox polymerization initiator.

  As the oxidizing agent and the reducing agent, it is recommended to use those having a small amount of ions (metal ions, etc.) contained in the compound or those containing no ionic components. Preferred combinations include hydroperoxides such as hydrogen peroxide, t-butyl hydroperoxide, cumene hydroperoxide, p-menthane hydroperoxide, diisopropylbenzene peroxide, 1,1,3,3-tetramethyl hydroperoxide. A combination of one or more oxidizing agents selected from peroxides such as oxides and one or more reducing agents selected from ascorbic acid, tartaric acid and erythorbic acid is preferred. In particular, a combination using hydrogen peroxide as an oxidizing agent and one or more compounds selected from ascorbic acid, tartaric acid, and erythorbic acid as a reducing agent is preferable.

  The redox polymerization initiator (the sum of the reducing agent and the oxidizing agent) is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, with respect to 100 parts by mass of the monomer components. More preferably, it is 1 part by mass or more, preferably 5 parts by mass or less, more preferably 4 parts by mass or less, and still more preferably 3 parts by mass or less.

  In addition, the polymerization initiator may be charged in its entirety (preferably emulsified and dispersed together with the monomer component) at the beginning (before the start of the reaction). A part of the polymerization initiator is initially charged, and the rest is continuously added to the feed. Alternatively, the pulse may be intermittently added, or a combination of these may be added.

  In addition, it is preferable that a basic substance is 0.3 mass part or less with respect to a total of 100 mass parts of a monomer component in a reaction liquid, More preferably, it is 0.1 mass part or less.

  The reaction temperature at the time of performing the polymerization reaction is preferably, for example, 30 ° C. or higher, more preferably 60 ° C. or higher, preferably 100 ° C. or lower, more preferably 95 ° C. or lower. If the reaction temperature is within this range, the polymerization reaction can be easily controlled. The reaction time is usually preferably 10 minutes to 1200 minutes, more preferably 30 minutes to 360 minutes.

In order to control the particle diameter of the toner external additive to be produced, it is preferable to control the diameter of the droplet containing the monomer component before or during the polymerization reaction. Agitation power in performing the polymerization reaction, for example, may preferably be 0.01 kW / m ³ or more, more preferably, 0.05 kW / m ³ or more, 0.1 kW / m ³ or more, 2.0 kW / m ³ or less is preferable, and 1.0 kW / m ³ or less and 0.5 kW / m ³ or less.

  The obtained toner external additive is preferably concentrated or solid-liquid separated as necessary, and dried. In drying, spray drying is preferably performed at an outlet temperature of 75 ° C. or higher (preferably 80 ° C. or higher). Since the toner external additive of the present invention has good dispersibility, it hardly aggregates and can be easily loosened even in the case of aggregation. For this reason, although crushing is unnecessary, you may crush etc. as needed.

  The toner external additive of the present invention is composed of a polymer containing a specific monomer unit, has a small coefficient of variation in particle diameter and a narrow particle diameter distribution, and thus has good dispersibility. In addition, when an external toner additive is added to the toner, adhesion to the toner is good and slipperiness (fluidity) can be imparted to the toner. For this reason, the toner external additive of the present invention suppresses aggregation and the like of developers (toners, particularly toners for developing electrostatic images) used in electrophotographic machines, copier printers, etc., and improves their fluidity. It is suitably used as an external additive.

2. Dispersion A dispersion containing the toner external additive is also included in the scope of the present invention. The dispersion includes a toner external additive, a solvent, and optionally a surfactant. The toner external additive of the present invention has good dispersibility and good storage stability as a dispersion.

  The proportion of the toner external additive is preferably 1 part by mass or more, more preferably 5 parts by mass or more, still more preferably 7 parts by mass or more, and preferably 30 parts by mass or less, in 100 parts by mass of the dispersion. It is 20 mass parts or less, More preferably, it is 15 mass parts or less.

Examples of the solvent include water; alcohols such as methanol, ethanol and isopropyl alcohol; ketones such as acetone and methyl ethyl ketone; and the like. The solvent is preferably water or a mixed solvent of water and an organic solvent such as alcohol or ketone.
The solvent is preferably 1 part by mass or more and 94 parts by mass or less, more preferably 5 parts by mass or more and 80 parts by mass or less, and further preferably 10 parts by mass or more and 70 parts by mass or less in 100 parts by mass of the dispersion.
Moreover, when a solvent contains water, 50 mass parts or more are preferable in 100 mass parts of solvents, More preferably, it is 80 mass parts or more, and it is preferable that it is 100 mass parts or less.

  The surfactant is preferably an anionic surfactant from the viewpoint of particle size control. Examples of the anionic surfactant include sodium lauryl sulfonate and sodium dodecyl benzene sulfonate. Among these, sodium dodecyl benzene sulfonate is particularly preferable. In addition, only 1 type may be sufficient as surfactant, and 2 or more types may be sufficient as it.

  When using a surfactant, the content is preferably 0.001 part by mass or more, more preferably 0.01 part by mass or more, and preferably 20 parts by mass or less, in 100 parts by mass of the dispersion. 15 parts by mass or less is more preferable. The more the surfactant, the easier it is to improve the dispersibility of the toner external additive in the dispersion, and the moisture content when the toner external additive is dried is suppressed by moderately suppressing the surfactant content. And foaming of the dispersion can be suppressed.

  The pH of the dispersion of the present invention is preferably 2-8.

The total amount of the toner external additive, the solvent, and the surfactant used as necessary is preferably 90 parts by mass or more, more preferably 95 parts by mass or more, and still more preferably 98 parts in 100 parts by mass of the dispersion. More than part by mass.
The dispersion may contain various additives as long as the dispersibility of the toner external additive is not impaired. The dispersion may be a mixture of the toner external additive (dry particles), a solvent, and a surfactant, or the reaction liquid for producing the toner external additive may be used as it is as a dispersion.

3. Toner Composition The toner composition of the present invention contains toner particles and a toner external additive. Since the toner external additive of the present invention has good dispersibility, it hardly aggregates and can be easily loosened even when it is aggregated. Therefore, even when the obtained toner external additive is added to the toner without crushing, it can be uniformly coated without adhering to the toner surface and overlapping. As a result, the fluidity of the toner composition is improved.

  In the toner composition, the content of the toner external additive is preferably 5 parts by mass or less, more preferably 100 parts by mass with respect to 100 parts by mass of the toner particles, from the viewpoint of suppressing aggregation due to blocking between the toner particles. 3 parts by mass or less, more preferably 2 parts by mass or less. Further, from the viewpoint of facilitating the preparation of the toner while maintaining the characteristics such as the fixing property and the transfer property, the content of the toner external additive is 0.1 parts by mass or more with respect to 100 parts by mass of the toner particles. Is more preferably 0.2 parts by mass or more, and still more preferably 0.5 parts by mass or more.

  As the toner particles, for example, a binder resin containing a colorant or a charge control agent can be used. Examples of the binder resin include polyester resin, styrene-acrylic resin, and polyolefin resin. Examples of the colorant include carbon black, phthalocyanine pigment, azo pigment, azo dye, nigrosine dye, extender pigment and the like. The content of these colorants is preferably 1 to 50 parts by mass, more preferably 1 to 40 parts by mass with respect to 100 parts by mass of the binder resin. Examples of the charge control agent include nigrosine dyes, azine dyes, metal complex salts, and quaternary ammonium salts. The content of the charge control agent is preferably 0 to 20 parts by mass, more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the binder resin. The particles may contain additives such as a release agent in addition to the colorant and charge control agent.

  The average particle size of the toner particles is preferably 1 μm or more and 25 μm or less, more preferably 3 μm or more, further preferably 5 μm or more, more preferably 20 μm or less, still more preferably 15 μm or less, particularly preferably. Is 10 μm or less.

  The ratio of the average particle diameter of the toner particles and the toner external additive (toner particles / toner external additive) is, for example, preferably 10 or more, more preferably 50 or more, and preferably 20000 or less, more preferably. 1000 or less, more preferably 500 or less, particularly preferably 200 or less.

  The toner composition may contain other components for the purpose of environmental stability, charge amount stabilization, transfer efficiency improvement and durability improvement in addition to the toner particles and toner external additives.

The toner composition can be produced by mixing an external toner additive and toner particles. When using the above dispersion, the solvent may be removed before mixing the dispersion containing the toner external additive and the toner particles, or the dispersion containing the toner external additive and the toner particles may be mixed. After that, the solvent may be removed.
Under the present circumstances, it is preferable that the peripheral speed of a stirring blade is 48-98 m / s, for example, More preferably, it is 58-82 m / s.
The stirring time is preferably 30 seconds to 10 minutes, more preferably 1 minute to 5 minutes.

The fluidity of the toner composition of the present invention is determined by using a powder tester (PT-E type manufactured by Hosokawa Micron Corporation) and a sieve having a mesh size of 150 μm, 100 μm and 45 μm (plain woven wire mesh, standard JIS Z 8801-1) with a strength of 4. After sieving 3 to 10 g of the toner composition with these sieves for 10 seconds while vibrating under the condition of 5, the toner composition remaining on the sieve with an opening of 150 μm is A and the toner composition on the sieve with an opening of 100 μm When the remaining amount is B and the remaining amount of the toner composition on the sieve having an opening of 45 μm is C, the evaluation can be made based on the fluidity index (%) represented by the following formula.
Fluidity index (%) = [(A + 0.6 × B + 0.2 × C) / measured sample weight] × 100

  The fluidity index (%) is preferably 80% or less, and more preferably 50% or less.

  Further, in the toner composition, it is preferable that composite particles are formed on the surface of the toner particles so that the toner external additives are not overlapped. Since the coefficient of variation of the toner external additive is small and the particle size distribution is narrow, blocking of such composite particles (particles having the toner particle surface coated with the toner external additive) is effectively suppressed, and the fluidity is improved.

  The adhesion of the toner external additive in the composite particles can be evaluated by the adhesion dispersibility index, and the adhesion dispersibility index is preferably 5% or more, more preferably 6% or more. It may be 50% or less, further 20% or less, particularly 10% or less.

Further, since the composite particles of the present invention are covered with a toner external additive having good adhesion to the toner particles, the area exposed on the toner particle surface without being covered with the toner external additive (exposed) The ratio of (area) is suppressed. For example, the ratio of the exposed area is preferably 95% or less, and more preferably 90% or less. Moreover, it is 10% or more normally, for example, 55% or more, Furthermore, 82% or more may be sufficient. The smaller the ratio of the exposed area, the better the fluidity of the composite particles.
The fluidity evaluation method of the toner composition can also be applied to composite particles, and the fluidity index (%) of the composite particles (aggregates) is preferably 80% or less, and 50% or less. It is more preferable that

  In particular, the toner composition and composite particles are suitable for toner (for example, toner for electrostatic charge development) applications.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, but may be appropriately modified within a range that can meet the purpose described above and below. Of course, it is possible to implement them, and they are all included in the technical scope of the present invention. In the following, “part” means “part by mass” and “%” means “mass%” unless otherwise specified.

(1) Measurement of average particle diameter and particle size distribution (CV value) of toner external additive A dispersion of toner external additive obtained in the following production example was diluted with ion-exchanged water, and a light scattering particle size distribution measuring device (Particle) was used. The volume average particle diameter (nm) of the toner external additive was determined by measurement with “Nicomp Model 380” manufactured by Sizing Systems.
Further, the coefficient of variation (CV value:%) was determined from the following equation from the volume average particle diameter obtained by the above apparatus and the standard deviation of the particle diameter.
Coefficient of variation (CV value:%) = 100 × (standard deviation of particle diameter / volume average particle diameter)

(2) Fluidity Evaluation Using a powder tester (PT-E type manufactured by Hosokawa Micron Corporation), a sieve having a mesh size of 150 μm, 100 μm, and 45 μm (plain woven wire mesh, standard JIS Z 8801-1) is used under a condition of strength 4.5. After sieving for 2 seconds and sieving the composite particles, the remaining amount of the composite particles on each sieve was measured and calculated using the following formula.
Fluidity index (%) = [(A + 0.6 × B + 0.2 × C) / measured sample weight] × 100
A: remaining amount of composite particles (g) on a sieve having an opening of 150 μm, B: remaining amount of composite particles on a sieve having an opening of 100 μm (g), C: remaining amount of composite particles on a sieve having an opening of 45 μm (g)
A smaller fluidity value was better and was evaluated according to the following criteria.
○: 50% or less △: Over 50%, 80% or less ×: Over 80%

Synthesis example 1
In a reaction vessel made of stainless steel having a capacity of 3 L equipped with a stirrer, a thermometer and a cooler, 825 parts of deionized water as a reaction solvent and 1.6 parts of sodium dodecylbenzenesulfonate as an emulsifier (active ingredient 60%, (Hereinafter referred to as “DBSNa”), and the internal temperature was raised to 75 ° C. and kept at the same temperature.
In a reaction vessel 1 different from the reaction kettle, 140 parts of methyl methacrylate (hereinafter referred to as “MMA”) as an alkyl (meth) acrylate monomer and divinylbenzene (81% active ingredient) as a crosslinkable vinyl monomer, Monomer mixture 1 was prepared by mixing 60 parts (referred to as "DVB").

  Next, after replacing the inside of the reaction kettle with nitrogen gas, 20 parts of the monomer mixture 1 prepared separately (10% of the total amount of the monomer mixture), 50 parts of 0.4% L-ascorbic acid aqueous solution and 0.27 % Initial hydrogen peroxide solution was added to the reaction kettle to carry out an initial polymerization reaction, and 450 parts of 0.4% L-ascorbic acid aqueous solution and 450 parts of 0.27% hydrogen peroxide water were added. The remaining 180 parts of the monomer mixture 1 was uniformly dropped over 4 hours from different charging ports into the reaction kettle. After completion of the dropping, the liquid temperature was raised to 85 ° C. and held at the same temperature for 2 hours, and then the reaction solution was cooled to obtain a toner external additive dispersion (solid content concentration: 10.0%). Table 1 shows the average particle diameter and CV value of the toner external additive 1.

  The obtained toner external additive dispersion was spray-dried with a spray dryer (external temperature 80 ° C.) equipped with a four-fluid nozzle to obtain a dry powder (toner external additive 1). This dry powder (toner external additive 1) hardly aggregated and could be easily loosened even when aggregated.

Synthesis Examples 2-4
Instead of using 140 parts of methyl methacrylate, 60 parts of divinylbenzene and 1.6 parts of emulsifier, synthesis was performed except that alkyl (meth) acrylate monomers, crosslinkable vinyl monomers, and emulsifiers were used in the proportions shown in Table 1. In the same manner as in Example 1, toner external additives 2 to 4 were obtained. Table 1 shows the average particle diameter and CV value of the toner external additives 2 to 4. The toner external additive 2 hardly aggregates, and even when aggregated, the toner external additive 2 was easily loosened, whereas the toner external additives 3 and 4 were difficult to loosen.

Synthesis example 5
A solution obtained by mixing 700 parts of ultrapure water, 300 parts of methanol and 3.29 parts of 25% aqueous ammonia was put into a four-necked flask equipped with a condenser, a thermometer, and a dripping port, and stirred. While continuing stirring, 110 parts of 3-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .; “KBM-503”) was added from the dropping port to synthesize polyorganosiloxane particles. While continuing stirring, 173 parts of 3-methacryloxypropyltrimethoxysilane was added, and the reaction was further continued to grow particles. After 2 hours from the start of the reaction, a dispersion of polyorganosiloxane particles was obtained.

  225 parts of methyl methacrylate and 75 parts of ethylene glycol dimethacrylate were mixed, and 6.6 parts of 2,2 '-(2,4-dimethylvaleronitrile) was dissolved in this mixture. This mixture was mixed with 240 parts of ion-exchanged water and 1.5 parts of polyoxyethylene distyrylphenyl ether sulfate ammonium salt, and then mixed with 8000 using a homomixer (manufactured by Primix; “TK Homomixer MARKII”). A pre-emulsion was prepared by stirring for 5 minutes on rotation.

  The whole amount of the pre-emulsion was charged into a four-necked flask equipped with a condenser, a thermometer, and a dripping port and stirred. Dilute sulfuric acid obtained by diluting 0.08 part of 96% sulfuric acid with 430 parts of ion-exchanged water was added to the flask, and then 55 parts of the polyorganosiloxane particle dispersion was added. After the addition, stirring was continued for 90 minutes to allow the seed particles to absorb the pre-emulsion. The temperature at the time of absorption was 23 ° C.

  After completion of preemulsion absorption, 520 parts of ion-exchanged water was added, the temperature was raised to 60 ° C., and a polymerization reaction was performed in a nitrogen gas atmosphere. After confirming the exothermic peak due to the initiation of polymerization, the mixture was aged at 75 ° C. for 2 hours to obtain organic-inorganic composite fine particles having a mass average particle diameter of 5 μm. After solid-liquid separation with filter paper, it is dried with a hot air dryer at 80 ° C. for 2 hours and then crushed with a lab jet mill (manufactured by Nippon Pneumatic Kogyo Co., Ltd.) to obtain organic-inorganic composite fine particles as spherical test particles. It was.

Examples 1 to 3, Comparative Examples 1 and 2
5 parts of spherical test particles shown in Table 1 and 0.05 part of the toner external additive obtained in the above synthesis example were mixed at room temperature with a mixer (“Labo Milser LM-PLUS”, manufactured by Iwatani Corp.). The mixture was uniformly mixed at 65 m / s (rotational speed 20,000 rpm) for 2 minutes, and an adhesion test was performed to obtain composite particles.
In Table 1, the organic / inorganic composite fine particles represent the particles described in Synthesis Example 5, and the metal particles represent silicon iron (average particle diameter 6 μm, specific surface area 0.13 m ² / g).

  The toner external additive of the present invention is composed of a polymer containing a structural unit derived from a specific monomer, and has a small coefficient of variation in particle size and a narrow particle size distribution, so that the dispersibility is good, and the toner external additive When used as an agent, it has good adhesion to the toner and can impart slipperiness (fluidity) to the toner surface. For this reason, the toner external additive of the present invention suppresses agglomeration of a developer (toner, particularly toner for developing an electrostatic image) used in an electrophotographic machine, a copying machine, a printer, and the like, and improves their fluidity. It is preferably used as an external additive.

Claims (4)

It is composed of a polymer containing a crosslinkable monomer unit having two or more ethylenic double bonds in one molecule in a proportion of 10% by mass to 50% by mass,
The volume average particle diameter is 5 nm or more and 100 nm or less,
A toner external additive having a coefficient of variation in particle diameter of 30% or less ,
The toner external additive further has an alkyl (meth) acrylate monomer unit having an alkyl group having 1 to 4 carbon atoms,
A toner external additive comprising a structural unit derived from a monomer other than the crosslinkable monomer and the alkyl (meth) acrylate monomer in a proportion of 0% by mass or more and 10% by mass or less .   The toner external additive according to claim 1, wherein the crosslinkable monomer is an aromatic crosslinkable monomer. 1 part by mass of the toner external additive and 100 parts by mass of spherical test particles having a volume average particle diameter of 5 μm are mixed for 2 minutes at a rotational speed of 20,000 rpm at room temperature, and the toner external additive is mixed with the spherical test particles. 3. The toner external additive according to claim 1, wherein the adhesion dispersibility index calculated based on the following formula is 5% or more when the adhesion test is performed.
Adhesive dispersibility index (%) = independent fine particle density (number / μm ² ) / maximum theoretical particle number (number / μm ² ) × 100
However, the density of the independent fine particles refers to the amount of toner particles adhering to the surface of the spherical test particle when the surface of the spherical test particle after the adhesion test is observed with a scanning electron microscope at a magnification of 15,000 to 20,000 times. This represents the number density of the additive, and when two or more toner external additives are adhered to each other, the adhered toner external additives are counted as one.
The maximum number of theoretical particles (number / μm ² ) is a value determined by the following formula.
Maximum number of theoretical particles present (number / μm ² ) = 0.9 / {(π / 4) × square of volume average particle diameter (μm) of toner external additive} And toner particles, toner compositions comprising toner external additive according to any one of claims 1-3.