JP6450255B2 - Method for producing binder resin for toner, and method for producing toner - Google Patents

Description

The present invention relates to a process for producing a binder for a toner resins, and a method of manufacturing a toner over.

  As a method for developing an electrostatic image, in recent years, technological development of a dry development system has been rapidly advanced. Various methods are known for fixing images in dry development, but contact heat fixing systems represented by heating roller fixing machines are more efficient than contactless heating fixing systems such as hot plate fixing machines. In particular, it is excellent in that high-speed fixing and low-temperature fixing are possible. In the heating roller fixing method, a toner image obtained by developing with toner on an electrostatic recording body (photosensitive drum) is transferred to a transfer sheet such as paper, and then the transfer sheet is passed through a heating roller to be heated and pressed. As a result, the toner image is fused to the sheet and fixed. However, when fixing is performed using the conventional toner using the heating roller fixing method, the surface of the heating roller and the toner come into contact with each other in a molten state, so that the toner adheres to the surface of the heating roller and retransfers to the next transfer sheet. As a result, there is a problem that the phenomenon of fouling, that is, the offset phenomenon occurs.

  Generally, a toner is composed of additive components such as a colorant component, a release agent, a charge control agent, and the like composed of a resin component, a pigment, a magnetic powder, a dye, and the like. The lower the melt viscosity, that is, the lower the molecular weight of the resin component, the better the fixing efficiency. On the other hand, the higher the melt viscosity of the resin component, that is, the higher the molecular weight of the resin component, the less likely the offset phenomenon occurs. Therefore, for the purpose of surely fixing at the fixing temperature and preventing an undesirable offset phenomenon, that is, for the purpose of realizing excellent fixability and offset resistance, a low molecular weight polymer and a binder resin for toner are used. Methods have been studied for inclusion of mixtures with high molecular weight polymers.

  As a method for producing such a binder resin for toner, for example, in Patent Document 1 below, a step of coexisting and mixing raw materials including a first resin, a second resin and waxes, and simultaneously and / or thereafter A method for producing a binder resin for toner comprising a step of removing volatile components is disclosed.

JP 2005-165124 A

  However, the method for producing a binder resin for toner described in Patent Document 1 still has room for improvement in terms of fixability and offset resistance.

The present invention has been made in view of the above circumstances, an excellent method for producing fixability and offset resistance can be made to impart a toner binder resins, and manufacturing method of toner over the toner The purpose is to provide.

  The inventors of the present invention have intensively studied to develop a method for producing a binder resin for toner that solves the above problems. And in the state which melt | dissolved the metal salt used in one of the methods of obtaining 2nd resin of patent document 1 with water with 2nd resin and 1st resin, when 2nd resin is removed, 2nd resin will be In the case of containing a carboxyl group, it was found that metal ions obtained from the metal salt act as a crosslinking agent to crosslink the second resin. Then, the inventors crosslink the second resin, and if the first resin is included in the cross-linked second resin, the cross-linked second resin is formed on the surface of the toner binder resin. As a result, the anti-offset property is excellent due to the presence of a large amount. When the toner is fixed with a heating roller, the first resin melts and moves from between the second resin to the surface, so that the fixing property is excellent. Therefore, I thought that the above problem could be solved. Thus, the inventors have completed the present invention.

That is, the present invention mixes a first resin, a second resin having a weight average molecular weight larger than that of the first resin and containing a carboxyl group, and a polyvalent metal salt solution containing a polyvalent metal salt and water. For a toner that produces a binder resin for a toner through a mixing step of preparing a mixture by charging the mixture into a tank and a water removal step of removing water from the mixture simultaneously with and / or after the mixing step a method of manufacturing a binder resin, wherein the water removing step and simultaneously and / or thereafter, the second resin the polyvalent metal salt thus crosslinked polyvalent metal ions derived from the, the said first resin A cross-linking step that does not cross-link with polyvalent metal ions derived from the polyvalent metal salt, and in the mixture, the polyvalent metal salt is 0.5 to 2.1 parts by mass with respect to 100 parts by mass of the second resin. It will be a proportion It is contained in a method for producing a binder resin for toner.

  According to the present invention, it is possible to produce a toner binder resin capable of imparting excellent fixability and offset resistance to toner.

  About the reason why the above-mentioned effect is obtained, the present inventors presume as follows.

  That is, when moisture is removed in the moisture removal step, the carboxyl group of the second resin is selectively cross-linked by polyvalent metal ions derived from the polyvalent metal salt, and the first resin is contained in the cross-linked second resin. Can be included. For this reason, a large amount of the crosslinked second resin is present on the surface of the binder resin for toner. Therefore, when a toner is manufactured using the binder resin for toner, even if the obtained toner comes into contact with the transfer sheet in a molten state, the toner hardly adheres to the surface of the heating roller and is transferred to the next transfer sheet. The phenomenon of shifting and fouling is suppressed, and the offset resistance is excellent. Further, when the toner is fixed on the transfer sheet with the heating roller, the first resin melts and moves from the second resin to the surface side, so that the fixing property is excellent. Thus, according to the present invention, the present inventors presume that the above effect can be obtained.

Further, the obtained binder resin for toner can further improve the hot / high temperature offset property without deteriorating the toner fixing property.
The present invention also includes a first resin, a second resin having a weight average molecular weight larger than that of the first resin and containing a carboxyl group, and a polyvalent metal salt solution containing a polyvalent metal salt and water. For a toner that produces a binder resin for a toner through a mixing step of preparing a mixture by charging the mixture into a tank and a water removal step of removing water from the mixture simultaneously with and / or after the mixing step A method for producing a binder resin, wherein the second resin is crosslinked with polyvalent metal ions derived from the polyvalent metal salt simultaneously with and / or after the water removal step, and the first resin is mixed with the polyvalent resin. A method for producing a binder resin for toner, comprising a crosslinking step in which crosslinking is not caused by polyvalent metal ions derived from a valent metal salt, wherein the first resin and the second resin are composed of a styrene polymer.
According to the present invention, it is possible to produce a toner binder resin capable of imparting excellent fixability and offset resistance to toner. In addition, a toner binder resin capable of imparting a good balance between hardness and brittleness to the toner can be produced.
In the said manufacturing method, it is preferable that the said 2nd resin and the said polyvalent metal salt solution are thrown into the said mixing tank in the mixed state in the said mixing process.

  In this case, the first resin, the second resin, and the polyvalent metal salt can be mixed more uniformly in the mixing tank. For this reason, a uniform crosslinked structure is obtained from the second resin and the polyvalent metal salt, and the first resin is uniformly contained in the crosslinked structure. As a result, it is possible to produce a toner binder resin capable of imparting better fixability and offset resistance to the toner.

  In the manufacturing method, in the mixing step, the second resin is preferably charged into the mixing tank in the form of an aqueous dispersion.

  In this case, what is obtained by emulsion polymerization or the like can be put into the mixing tank as it is, and in the mixture obtained by mixing the first resin, the second resin and the polyvalent metal salt solution, the homogeneity of the second resin is improved. Can be higher.

  In the mixture, the polyvalent metal salt solution is preferably contained so as to have a ratio of 0.5 to 2.1 parts by mass with respect to 100 parts by mass of the second resin.

  In this case, the obtained binder resin for toner can further improve the hot / high temperature offset property without deteriorating the fixing property of the toner.

  In the said manufacturing method, it is preferable that the said polyvalent metal salt is comprised with a bivalent metal salt.

  In this case, the uniformity of the first resin and the second resin is less likely to be inhibited by crosslinking.

  In the said manufacturing method, it is preferable that the said bivalent metal salt is comprised by at least 1 sort (s) chosen from the group which consists of zinc salt and calcium salt.

  In this case, the uniformity of the first resin and the second resin is not particularly disturbed by the crosslinking.

  In the said manufacturing method, it is preferable that the mixture ratio of the said 1st resin in the sum total 100 mass% of said 1st resin and said 2nd resin is the range of 50-80 mass%.

  In this case, it is possible to produce a toner binder resin capable of imparting a good balance between fixing property and offset resistance to the toner.

  Furthermore, the present invention provides a preparation step of preparing a binder resin for toner by the above-described method for producing a binder resin for toner, mixing the binder resin for toner prepared in the preparation step and a colorant. And a colorant mixing step for obtaining the toner.

  According to this toner manufacturing method, it is possible to manufacture a toner having excellent fixability and offset resistance.

According to the present invention, the toner binder for tree method for producing lipid capable of imparting excellent fixing property and offset resistance of the toner, and manufacturing method of toner over it is provided.

  Hereinafter, the present invention will be described in more detail.

<Method for producing binder resin for toner>
The method for producing a binder resin for toner according to the present invention includes a first resin, a second resin having a weight average molecular weight larger than that of the first resin and containing a carboxyl group, a polyvalent metal salt and water. Through a mixing step (1) of adding a valent metal salt solution to a mixing tank and mixing to prepare a mixture, and a water removal step (2) of removing water from the mixture simultaneously with and / or after the mixing step, A method for producing a toner binder resin, wherein the second resin is produced by a polyvalent metal ion derived from a polyvalent metal salt simultaneously with and / or after the water removal step (2). This is a method for producing a binder resin for toner, which comprises a crosslinking step (3) for selectively crosslinking.

  According to the above-described method for producing a toner binder resin, it is possible to produce a toner binder resin capable of imparting excellent fixability and offset resistance to the toner.

  Hereinafter, the mixing step (1), the water removal step (2) and the crosslinking step (3) will be described in detail.

[Mixing process]
In the production method of the present invention, the first resin, the second resin, and the polyvalent metal salt solution are charged into a mixing tank and mixed to prepare a mixture.

(First resin)
The method for producing the first resin is not necessarily limited, but it does not require the use of an organic solvent or an emulsifier, the production operation is relatively easy, and it is easy in the molten state in the mixing step (1). From the standpoint that it can be added, a method of producing the first resin by bulk polymerization of a vinyl monomer is preferable.

  In addition, as a method of charging the first resin into the mixing tank in the mixing step (1), a method of charging the solventless resin in the form of flakes, powders, granules, or blocks; a solventless resin in a molten state The method of throwing in is mentioned.

  Here, the above “solvent-free resin” refers to a resin having a water or organic solvent content of 10% by mass or less, preferably 5% by mass or less, and particularly preferably substantially free of water or organic solvent. To do.

  Of these charging methods of the first resin, a method in which a solventless resin is charged in a molten state is preferable because it enables continuous operation and the resulting binder resin has high homogeneity.

  Bulk polymerization can be carried out by coexisting a vinyl monomer and a polymerization initiator dissolved in the monomer, and heating a raw material mixture substantially free of a solvent, a dispersant, an emulsifier, etc. to the polymerization temperature. . The polymerization method may be a batch polymerization method in which all raw materials are reacted in one polymerization tank, a continuous method in which raw material addition, polymerization and polymer removal are continuously performed, or a semi-continuous method in which these are combined. However, it is efficient and preferable to perform bulk polymerization continuously and directly mix the obtained first resin in the molten state with the second resin and the polyvalent metal salt solution.

  It is preferable that the 1st resin used by this invention has the molecular weight characteristic of the specific range measured by the method described below.

Measurement of molecular weight properties:
“TSK gel GMH xl” [trade name: manufactured by Tosoh Corporation] Using a gel bar gel permeation chromatography (GPC) apparatus “HLC-8220” [trade name; manufactured by Tosoh Corporation] equipped with two columns, Various resin samples are dissolved in tetrahydrofuran (THF) to a concentration of 0.2% by mass, and about 150 μL of this solution is injected into the apparatus at a temperature of 20 ° C., and then THF is flowed at a flow rate of 1 mL / min. Measure. In the measurement of the molecular weight characteristics of the sample, the molecular weight of the sample is included in a range in which the logarithm of the molecular weight and the count number of the calibration curve prepared by several monodisperse polystyrene standard samples are linear. Select a condition.

  The weight average molecular weight (MwL) of the first resin measured by the measurement of the molecular weight characteristics is preferably 1,000 to 50,000, more preferably 1,000 to 30,000, and particularly preferably 1,000 to 20,000. If MwL is equal to or greater than the above lower limit, the resulting toner using the toner binder resin has good fixability, and causes problems such as agglomeration in the developing machine and shortened life as a developer. It is preferable because it is difficult to resist and has excellent storage stability, and it is difficult to cause problems such as solidification during high-temperature storage. If MwL is less than or equal to the above upper limit, the toner using the resulting binder resin for toner is less likely to be spent and finer, and has excellent fixability in a low temperature region. This is preferable because the lower limit temperature rises and it is difficult to cause problems such as poor cold offset.

  The first resin used in the present invention is any resin as long as it is a resin used as a binder resin for the toner and is not crosslinked by the polyvalent metal ions in the polyvalent metal salt solution. There is no restriction in particular and it can be used. Examples of the first resin include a styrene polymer, an epoxy resin, a polyester resin, a styrene-butadiene copolymer, and the styrene polymer is used because it easily obtains performance as a toner. preferable. However, these resins are required not to have a carboxyl group so as not to be crosslinked by the polyvalent metal ions. That is, the acid value of these resins needs to be 0 KOHmg / g.

  The styrene polymer is a (co) polymer obtained by (co) polymerizing a monomer containing a styrene monomer as a main component, for example, 50% by mass or more. Examples include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, pt-butylstyrene, pn- Hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p-phenyl styrene, p-chloro styrene, 3,4-dichloro styrene, etc. Of these, styrene is most preferred.

  The other monomer that can be copolymerized with the styrenic monomer is not particularly limited as long as it is a monomer that can be copolymerized with the styrenic monomer. Esters are preferred, and as such acrylic acid esters and methacrylic acid esters, for example, acrylic acid butyl ester is preferably used.

  The glass transition temperature (TgL) of the styrene polymer suitably used as the first resin in the present invention is preferably in the range of 40 to 80 ° C, more preferably in the range of 50 to 70 ° C.

  The polymerization temperature of the bulk polymerization, which is a preferred method for producing the first resin used in the present invention, is preferably 130 to 250 ° C, more preferably 170 to 250 ° C, and particularly preferably 190 to 230 ° C. It is preferable that the reaction temperature is equal to or higher than the above lower limit temperature because bulk polymerization shows a good reaction rate and there is no inconvenience such as an excessively high molecular weight peak (MpL) of the resulting polymer. Also, if the reaction temperature is lower than the above upper limit temperature, problems such as depolymerization reaction and increase in the number of oligomers having a molecular weight of 500 or less are unlikely to occur. A toner using a resin is preferable because its storage stability and difficulty in developing spent and finer toners.

  As the polymerization initiator used for bulk polymerization, any conventionally known oil-soluble polymerization initiator can be used. Suitable polymerization initiators include, for example, benzoyl peroxide, t-butyl hydroperoxide, di-t-butyl hydroperoxide, cumene hydroperoxide, t-hexyl hydroperoxide, p-menthane hydroperoxide, azobisisobutyronitrile. Can be mentioned. In the present invention, it is particularly preferable to use a high temperature of 170 ° C. or higher as the reaction temperature. Among these initiators, high-temperature decomposables such as t-butyl hydroperoxide and di-t-butyl hydroperoxide are used. It is particularly preferred to use an initiator. The amount of the polymerization initiator used is preferably 0.01 to 5 parts by mass, more preferably 0.03 to 5 parts by mass, and 0.05 to 1 part by mass with respect to 100 parts by mass in total of the monomers. It is particularly preferred.

  It is preferable to set the reaction temperature and the reaction residence time so that the conversion rate of the styrenic first resin obtained as described above is 90% or more, preferably 95% or more, more preferably 97% or more. However, if necessary, the residual monomer can be recovered by a thin film distillation apparatus or the like.

  The bulk polymerized low molecular weight polymer thus obtained is particularly preferable because it can increase the charge retention of the toner and reduce the generation of odor.

(Second resin)
In the method for producing a binder resin for toner according to the present invention, in the mixing step (1), the second resin is introduced into the mixing tank and mixed together with the first resin described above. The method of charging the second resin into the mixing tank is not necessarily limited, and is a method of charging in the form of an aqueous dispersion; the dispersion stability of the aqueous dispersion is appropriately reduced by a known method to form an aqueous sludge. In the mixture obtained by mixing the first resin, the second resin and the polyvalent metal salt solution, the one obtained by emulsion polymerization or the like can be added as it is. For the reason that the homogeneity of the two resins can be further increased, a method of charging in the form of an aqueous dispersion is more preferable. Moreover, as a charging method of 2nd resin, the method of throwing into a mixing tank in the state mixed with the polyvalent metal salt solution, the method of charging into a mixing tank in the state mixed with the 1st resin and the polyvalent metal salt solution, etc. are mentioned. However, as a method for charging the second resin, a method of charging the second resin into the mixing tank in a mixed state with the polyvalent metal salt solution is preferable. In this case, the second resin can be more uniformly crosslinked.

  The aqueous dispersion of the second resin (high molecular weight resin) is not particularly limited as long as the second resin is dispersed in an emulsified state. For example, the resin is appropriately washed with a known emulsifier in water. Examples include aqueous resin dispersions that are forcibly emulsified and dispersed, aqueous resin dispersions obtained by emulsion polymerization, and the like, which are obtained by emulsion polymerization from the viewpoint of being stable during storage and mixing with the first resin. An aqueous resin dispersion is preferred. Alternatively, the aqueous dispersion of the second resin may be an aqueous resin dispersion in which the resin particles are self-stabilized according to the polarity of the resin itself and no emulsifier is used.

  The molecular weight characteristics of the second resin used in the present invention are also measured in accordance with the method described in the above “Measurement of molecular weight characteristics”. The weight average molecular weight (MwH) of the second resin thus measured may be larger than the weight average molecular weight (MwL) of the first resin, but is preferably 100,000 or more, particularly 200,000 or more. preferable. When the MwH is equal to or higher than the lower limit value, it is preferable because the toner using the obtained binder resin for toner exhibits excellent fixability and does not generate hot offset and has a wide fixable temperature range. Further, if necessary, an intermediate molecular weight resin having an intermediate molecular weight between the first resin and the second resin may be used together with the second resin.

  The second resin used in the present invention is not particularly limited as long as it has a carboxyl group and has a weight average molecular weight larger than that of the first resin. As such 2nd resin, what is the same kind of resin as said 1st resin and has a carboxyl group can be used. Specifically, as the second resin, a styrene polymer such as a copolymer of a styrene monomer and an acrylic monomer can be used. In this case, when a styrene polymer is also used for the first resin, the homogeneity of the second resin is further improved in the obtained binder resin for toner.

  When an aqueous dispersion is used as the second resin, the average particle size of the dispersed particles is preferably in the range of 30 nm to 1000 nm. If the particle size is less than or equal to the upper limit, the compatibility and dispersibility with the first resin are excellent, the toner has excellent fixability using the resulting toner binder, and hot offset occurs. Therefore, it is preferable because the fixing temperature range is wide. In addition, if the particle size of the dispersed particles in the resin emulsion dispersion is equal to or greater than the lower limit value, a relatively small amount of emulsifier can be used during emulsion polymerization, so that the toner using the resulting toner binder can be used. This is preferable because problems such as a low electrical resistance are unlikely to occur.

  The average particle size of the dispersed particles in the aqueous dispersion of the second resin is a value measured by a laser diffraction type particle size distribution measuring device. Specifically, “Mastersizer 2000” [trade name; Sysmex Corporation Is a mass average particle diameter measured using

  When the aqueous dispersion of the second resin used in the present invention is obtained by emulsion polymerization, this emulsion polymerization is carried out in the presence of a monomer, a water-soluble catalyst, an emulsifier and water as a polymerization medium, and heated to the polymerization temperature. Is done.

  The raw materials are all contained in the polymerization tank, and the polymerization may be carried out by raising the temperature to the polymerization temperature, or at least a part of water is contained in the polymerization tank and the remaining water and a single amount are added. Polymerization can also be carried out by intermittently or continuously adding some or all of the body, water-soluble catalyst and emulsifier. The monomer may be added alone to the polymerization tank, or the monomer may be previously emulsified in an aqueous emulsifier solution and the monomer emulsion may be added.

  The polymerization temperature is not particularly limited as long as it is a temperature at which the catalyst acts, but it is generally 30 to 150 ° C, preferably 40 to 100 ° C.

  As said monomer, in addition to monomers, such as acrylic acid, methacrylic acid, and acrylic ester used for the polymerization of the first resin, a polyvinyl monomer having two or more polymerizable double bonds Examples of such polyvinyl monomers include aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; for example, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and 1,3-butanediol. Polyol poly (meth) acrylate compounds such as dimethacrylate, 1,6-hexanediol diacrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, etc .; allyl methacrylate Unsaturated alcohol poly (me ) Acrylate compounds; N, N-divinyl aniline, divinyl ether, divinyl Ruff id, and other divinyl compounds such as triallyl cyanurate; there are. Of these, divinylbenzene, ethylene glycol dimethacrylate, 1,6-hexanediol diacrylate (1,6-HDDA) and the like are preferably used.

  These crosslinkable polyvinyl monomers are generally 0 to 2% by mass, preferably 0.01 to 1% by mass, particularly preferably 0.02 to 0.8% by mass, in a total of 100% by mass of the monomers constituting the second resin. Included in the ratio.

  Examples of the catalyst that can be used in the emulsion polymerization include any conventional water-soluble polymerization initiators such as hydrogen peroxide; alkyl hydroperoxides such as t-butyl hydroperoxide and t-amyl hydroperoxide; dialkyl peroxides. Persulfates such as ammonium persulfate, potassium persulfate and sodium persulfate; peroxyesters; peroxycarbonates; ketone peroxides such as methyl ethyl ketone peroxide and 2,2′-azobis (2-amidinopropane), 2,2′- Free radical polymerization initiators such as azo initiators such as azobis (4-cyanovaleric acid) can be used. The amount of the polymerization initiator used is preferably in the range of 0.03 to 1 part by mass, more preferably in the range of 0.05 to 0.8 part by mass, with respect to 100 parts by mass of the total mass of the above monomers, and 0.1 to 0.5 A range of parts by mass is particularly preferable.

  As a catalyst that can be used in the emulsion polymerization, a water-soluble redox polymerization initiator obtained by combining the above water-soluble polymerization initiator and a water-soluble reducing agent can also be used. As the polymerization initiator used for the water-soluble redox polymerization initiator, the above polymerization initiators can be used. As the reducing agent, for example, sodium sulfite, sodium bisulfite, sodium metabisulfite, sodium pyrosulfite, hypophosphite, ascorbic acid, tartaric acid, citric acid, glucose, sodium formaldehyde sulfoxylate and the like can be used. The peroxide in the water-soluble redox polymerization initiator is used in the range of 0.03 to 1 part by mass with respect to 100 parts by mass of the total mass of all monomers. Further, in addition to the water-soluble redox polymerization initiator, a small amount of a transfer metal such as ferrous sulfate, copper molybdate or the like can be used in combination.

  As an emulsifier that can be used in the emulsion polymerization of the second resin aqueous dispersion suitably used in the present invention, any of an anionic emulsifier, a nonionic emulsifier, a cationic emulsifier, an amphoteric emulsifier, and a reactive emulsifier is used. can do. As these emulsifiers, known types of emulsifiers can be used by a known method of use, and these emulsifiers can be used alone or in combination.

  The obtained second aqueous resin dispersion can be adjusted for pH by adding aqueous ammonia, an aqueous amine solution, an aqueous alkali hydroxide solution, or the like, if necessary. Such an aqueous dispersion usually has a solid concentration of generally 10 to 70% by mass, preferably 20 to 60% by mass, more preferably 30 to 50% by mass, and the viscosity is Usually 100 mPa · s (BH type rotational viscometer, 25 ° C., 20 rpm; the same as in the viscosity measurement conditions below) and below, and the pH is usually preferably in the range of 2-10.

  When emulsion polymerization is carried out, most of the monomers are generally converted into polymers, and the amount of the remaining monomers is extremely small. However, if the residual monomer concentration needs to be further reduced, for example, the residual monomer may be added by a method such as addition of one or more initiators or reducing agents after polymerization, blowing of steam or air, or the like. May be reduced.

  The acid value of the second resin is not particularly limited, but is preferably 2 to 33 KOH mg / g, and more preferably 3 to 16 KOH mg / g. In this case, when the acid value of the second resin is within the above range, the hot offset property of the toner using the obtained binder resin for toner becomes better as compared with the case where the acid value is less than 2 KOH mg / g. On the other hand, when the acid value of the second resin is within the above range, the fixability of the toner using the obtained binder resin for the toner is more difficult to deteriorate than when the acid value exceeds 33 KOH mg / g.

  Since the mixing ratio of the first resin and the second resin depends on the composition and weight average molecular weight of each resin, it is not generally defined, but in general, the first resin and the second resin The blending ratio of the first resin in the total 100% by mass of the resin is preferably in the range of 50 to 80% by mass, more preferably 55 to 75% by mass. When the blending ratio of the first resin is 50% by mass or more, the toner binding using the resulting toner binding resin has better offset resistance and the toner binding obtained in the low temperature region. This is preferable because the fixing property of the toner using the resin is excellent, and inconveniences such as an increase in the minimum fixing temperature are unlikely to occur. Further, when the blending ratio of the first resin is 80% by mass or less, the fixability of the toner using the obtained binder resin for toner is improved, and the fixable temperature range is narrow due to the occurrence of hot offset. This is preferable because inconveniences such as becoming less likely to occur.

(Polyvalent metal salt solution)
The polyvalent metal salt solution may be a solution containing a polyvalent metal salt and water. Since the polyvalent metal ion derived from the polyvalent metal salt is for crosslinking the carboxyl groups of the second resin, it may be divalent or more, and the valence is not particularly limited. The polyvalent metal salt is preferably composed of a divalent metal salt. In this case, compared with the case where the polyvalent metal salt is composed of a polyvalent metal salt containing a trivalent or higher-valent metal ion, the uniformity of the first resin and the second resin is less likely to be inhibited by the crosslinking.

  Examples of the divalent metal salt include divalent metal salts such as zinc salt, calcium salt, magnesium salt, iron (divalent) salt, and barium salt. These can be used alone or in combination. Of these, the divalent metal salt is preferably composed of a zinc salt, a calcium salt, or a combination of these salts. In this case, compared with the case where the divalent metal salt is composed of other than the zinc salt, calcium salt, or a combination of these salts, the uniformity of the first resin and the second resin is not particularly hindered by the crosslinking. Examples of the trivalent metal salts include metal salts such as aluminum salts and iron (trivalent) salts. Furthermore, examples of the tetravalent metal salt include metal salts such as titanium salts.

  Here, the polyvalent metal ion can be usually obtained by dissolving the polyvalent metal salt in water. The polyvalent metal salt is not particularly limited as long as it is a water-soluble metal salt. Examples of such a polyvalent metal salt include halides, sulfates, nitrates, phosphates, acetates, carbonates of various metals. A salt etc. can be mentioned. Among them, the metal salt is preferably an acetate salt because unnecessary acid is volatilized by heat during kneading.

  The polyvalent metal salt is preferably contained so as to have a ratio of 0.5 to 2.1 parts by mass with respect to 100 parts by mass of the second resin. In this case, the obtained binder resin for toner can further improve the hot offset property without deteriorating the toner fixing property.

  The polyvalent metal salt solution only needs to contain water as a solvent. Therefore, the solvent may be comprised only with water, and may be comprised with the liquid mixture of water and the organic solvent compatible with water. Here, examples of the organic solvent having compatibility with water include alcohols such as methanol, ethanol, propanol, and butanol.

  In the mixing step (1) in the present invention, the first resin, the second resin and the polyvalent metal salt solution described above are put into a mixing tank, and a mixing operation is performed while stirring by a mechanical or other method to prepare a mixture. . The mixing step is preferably performed at a temperature equal to or higher than the glass transition point of the first resin, more preferably at a temperature higher by 20 ° C. than the glass transition point. In this case, a uniform mixture of the first resin, the second resin, and the polyvalent metal salt solution is obtained, and various physical properties of the toner produced using the mixture as a toner binder resin are further improved.

  The above-described advantages of the mixing step (1) are derived from the aqueous dispersion or the resin particles or the resin particles in the aqueous dispersion which is a suitable form as the second resin during the mixing step (1). It is considered that the fine particles, the first resin composed of a solventless resin, and the polyvalent metal salt solution are brought into contact with each other, and the action of coalescing them in a dispersed state is promoted at the above-described temperature. .

  The mixing step (1) may be performed in an open state or a sealed state under normal pressure, and may be performed in a sealed pressure state in order to control the evaporation of volatile components such as moisture and organic solvents.

  The said mixing tank should just be a tank which can mix 1st resin, 2nd resin, and a polyvalent metal salt solution, for example, you may use a part of kneading machine as a mixing tank.

[Moisture removal process]
In the production method of the present invention, a moisture removing step (2) for removing moisture from the mixture is performed simultaneously with and / or after the mixing step (1). The water removal step (2) is a process of removing water by evaporation from the mixture in the mixing tank produced by the mixing step (1), and a solvent-free solvent from which most of the water has been removed by this step (2). A resin mixture in the state is obtained. At this time, if volatile impurities such as residual monomers are present in the mixture, these can also be removed at the same time.

  The water removal step (2) can be performed by heating the mixture obtained in the mixing step (1) to a temperature equal to or higher than the evaporation equilibrium temperature of the water in the mixture, and more efficiently by reducing the pressure under heating. Can be done. When moisture removal is performed at normal pressure, the temperature of the mixture obtained in the mixing step (1) may be set around 100 ° C., which is the boiling point of water as a solvent. The step (2) can be performed after the mixing step (1) is completed, but it is more efficient and preferable to perform both at the same time.

  The water removal step (2) is performed using, for example, a method in which the above mixture is heated as necessary and then introduced into a reduced pressure region to evaporate the water so as to be in a substantially solvent-free state by a so-called flash method. You can also.

[Crosslinking process]
In the production method of the present invention, the second resin is selectively crosslinked with polyvalent metal ions derived from the polyvalent metal salt in the polyvalent metal salt solution simultaneously with and / or after the water removal step (2). A crosslinking step (3) is performed. Here, “selectively cross-linking the second resin” means that only the second resin is cross-linked by polyvalent metal ions and the first resin is not cross-linked. If the first resin does not have a carboxyl group and the second resin has a carboxyl group, the polyvalent metal ions bind the carboxyl groups of the second resin, and the second resins have a carboxyl group. Are selectively crosslinked. As described above, by removing moisture, the polyvalent metal ions derived from the polyvalent metal salt in the polyvalent metal salt solution function as a crosslinking agent, and the carboxyl groups in the second resin can be cross-linked. It becomes possible. In the cross-linking step (3), the first resin and the second resin are not cross-linked from the viewpoint of obtaining a toner binder resin that imparts excellent fixability to the toner.

[Other processes]
Furthermore, in the production method of the present invention, when the composition of the mixture of the first resin, the second resin, and the polyvalent metal salt solution is made highly uniform, the mixing step (1), the water removal step (2), and After the cross-linking step (3), it is preferable to perform a kneading step (4) for further mechanical kneading. When a small amount of water remains in the mixture after the crosslinking step (3), it is preferable to perform a kneading treatment under conditions for further removing the water. The kneading step (4) is preferably performed when any one component of the first resin and the second resin is in a molten state because a more uniform mixture can be obtained.

  The mixing step (1), the water removal step (2), the crosslinking step (3) and the kneading step (4) performed as necessary are the second resin, the first resin, and the polyvalent metal used in the present invention. You may carry out in inert gas atmosphere, such as nitrogen and argon, which does not have affinity and reactivity with respect to any of salt solution and the solvent accompanying these. Thereby, when the obtained solvent-free resin mixture is used as a binder resin for toner, it is possible to remarkably improve the generation of odor when fixing a printer or a copying machine. Further, by performing these steps (1) to (4) while flowing the inert gas in a sealed state, volatile impurities such as residual monomers and solvents present in the resin mixture are more efficiently removed. be able to.

  In the present invention, the mixing step (1), the water removal step (2), the crosslinking step (3), and the kneading step (4) performed as necessary are means that can carry out these steps without any inconvenience. The method is not particularly limited, and can be performed using at least one means having a heating function, a mixing function, and / or a volatile component removal function.

  Preferable means having the above functions include, for example, a heating kneader, a Banbury mixer, a roll mill, a single-screw continuous kneader, a twin-screw continuous kneader, a continuous mixing and desolving machine, and a dryer. Among these means, the above-mentioned steps (1) to (4) can be carried out continuously, and the single-screw continuous kneader or the twin-screw continuous kneading in that these steps can be carried out efficiently with one apparatus. It is preferable to use a machine.

<Toner production method>
In the method for producing a toner of the present invention, a toner is prepared by mixing a toner binder resin prepared in the preparing step and a colorant with a preparation step of preparing the toner binder resin obtained as described above. The toner is manufactured through a colorant mixing step to obtain a toner.

  Specifically, a mixture containing a toner binder resin and a colorant is uniformly mixed and melted to obtain a molten mixture. After cooling the obtained molten mixture, the mixture is finely crushed by a jet mill or the like if necessary. After pulverization, the toner is classified by a classifier to obtain a toner having a desired particle size.

  Examples of the colorant include inorganic pigments, organic pigments, and synthetic dyes. Of these, inorganic pigments or organic pigments are preferably used. One or two or more pigments and / or one or two or more dyes may be used in combination. The amount of the colorant used is preferably 1 to 200 parts by weight, more preferably 3 to 150 parts by weight, based on 100 parts by weight of the binder resin for toner.

  Examples of the inorganic pigment include metal powder pigments such as zinc powder, iron powder, and copper powder; for example, magnetite, ferrite, bengara, titanium oxide, zinc white, silica, chromium oxide, ultramarine, cobalt blue, and cerulean blue. , Metal oxide pigments such as Milanel violet, trilead tetroxide; carbon pigments such as carbon black, thermatomic carbon and furnace black; for example, zinc sulfide, cadmium red, selenium red, mercury sulfide, cadmium yellow Examples thereof include sulfide-based pigments such as molybdenum red, barium yellow, strontium yellow, and chromium yellow, and chromate-based pigments such as miloli blue.

  Examples of organic pigments include azo pigments such as benzidine yellow, benzidine orange, permanent red 4R, pyrazolone red, resol red, brilliant scarlet G, bon maroon light; for example, orange II, acid orange R, oxine, quinoline. Acid dye pigments obtained by precipitating acid dyes such as yellow, tartrazine yellow, acid green, peacock blue and alkali blue with a precipitating agent; for example, basic dyes such as rhodamine, magenta, macalite green, methyl violet, and Victoria blue Basic dye pigments precipitated with tannic acid, tartar, phosphotungstic acid, phosphomolybdic acid, phosphotungstic molybdic acid, etc .; for example, metal salts of hydroxyanthraquinones, alizarin murder lake And mordant dye-based pigments; for example, phthalocyanine-based pigments such as phthalocyanine blue and sulfonated copper phthalocyanine; .

  Examples of the dyes include acridine dyes, aniline black, anthraquinone dyes, azine dyes, azo dyes, azomethine dyes, benzo and naphthoquinone dyes, indigo dyes, indophenol, indoaniline, indamine, leuco vat dyes, naphthalimide dyes, nigrosine Indulin, nitro and nitroso dyes, oxazine and dioxazine dyes, oxidation dyes, phthalocyanine dyes, polymethine dyes, quinophthalone dyes, sulfur dyes, tri- and diallylmethane dyes, thiazine dyes, xanthene dyes, Aniline black, nigrosine dye, and azo dye are used. As a more preferred dye, an azo dye having a salicylic acid, naphthoic acid or 8-oxyquinoline residue in the molecule and forming a complex salt with a metal such as chromium, copper, cobalt, iron, aluminum, etc. is used. .

  In addition to the binder resin for toner and the colorant, the mixture may further contain additives such as a charge control agent and a release agent as necessary.

  Examples of the charge control agent include nigrosine-based electron donating dyes for plus, metal salts of naphthenic acid or higher fatty acids, alkoxylated amines, quaternary ammonium salts, alkylamides, chelates, pigments, fluorine treatment activators Etc. Examples of the negative use include electron-accepting organometallic complexes, chelate compounds, chlorinated paraffin, chlorinated polyester, excess acid group polyester, copper phthalocyanine sulfonylamine, and the like.

  If necessary, a fluidity improver may be further added to the toner. Any fluidity improver can be used as long as it can be added to toner particles to increase fluidity. Examples thereof include hydrophobic colloidal silica fine powder, colloidal silica fine powder, hydrophobic titanium oxide fine powder, titanium oxide fine powder, hydrophobic alumina fine powder, alumina fine powder, and a mixed powder thereof.

  The toner manufactured as described above is a two-component developer composed of a toner and a carrier, and is preferably used as a two-component developer using a carrier having a resin coating layer as the carrier. The carrier having a resin coating layer is typically a carrier in which the surface of carrier core particles made of iron, nickel, ferrite, and glass beads is coated with an insulating resin coating layer. In general, fluorine resin, silicon resin, acrylic resin, styrene-acrylic copolymer resin, polyester resin, and polybutadiene resin are representative examples.

  When a two-component developer comprising the toner obtained by the present invention and a carrier having a resin coating layer is used, the two-component developer is contaminated by the toner particles adhering to the surface of the carrier particles. It is particularly suitable for a high-speed electrophotographic machine in that the spent is extremely small, the triboelectric charging characteristics of the carrier and the toner can be controlled, and the durability is excellent and the service life is long.

  The toner provided by the present invention is not limited to a two-component developer, but a one-component developer that does not use a carrier, for example, a magnetic one-component toner containing magnetic powder in the toner, It can also be applied to non-magnetic one-component toners that do not contain magnetic powder.

  Further, in the production of the toner, in addition to the binder resin obtained by the production method of the present invention, other binder resins such as styrene resins and polyester resins may be used as auxiliary blends. The proportion of the auxiliary binder resin in the total binder resin is preferably 30% by mass or less.

  Furthermore, when the binder resin for toner is manufactured by the manufacturing method of the present invention, the toner is directly manufactured by blending the above various additives together with the first resin, the second resin and the polyvalent metal salt solution. You can also.

  Next, the present invention will be described more specifically with reference to examples. The obtained toner samples were evaluated according to the following test methods.

[Production of first resin]
Production Example 1
Stirrer, heating device, cooling device, thermometer and dripping pump are provided, and 100 parts by mass of styrene (St) and 0.5 parts by mass of di-t-butyl peroxide are uniformly mixed in an autoclave controlled at 210 ° C. The monomer mixture liquid was continuously added in 30 minutes, and the bulk polymerization was carried out while maintaining the temperature at 210 ° C. for 30 minutes to obtain a solvent-free low molecular weight styrene resin. The obtained first resin had a weight average molecular weight MwL of 6,000 and a Tg of 65 ° C.

[Production of second resin]
Production Example 2
A container equipped with a stirrer and a dropping pump was charged with 27 parts by mass of deionized water and 1 part by mass of an anionic emulsifier “Neogen R” (trade name; sodium dodecylbenzenesulfonate; manufactured by Daiichi Kogyo Seiyaku Co., Ltd.). After stirring and dissolving, a monomer emulsion comprising St 69 parts by mass, butyl acrylate (BA) 30 parts by mass and methacrylic acid (MAA) 1 part by mass was added dropwise to obtain a monomer emulsion. .

  Next, in a pressure-resistant reaction vessel equipped with a stirrer, a pressure gauge, a thermometer, and a dropping pump, 120 parts by mass of deionized water was charged, and after replacing with nitrogen, the temperature was raised to 80 ° C. 15% by mass was added, and further 1% by mass of a 2% by mass potassium persulfate aqueous solution was added, and initial polymerization was carried out at 80 ° C. After completion of the initial polymerization, the temperature was raised to 85 ° C., and the remaining monomer emulsion and 4 parts by mass of 2% by mass potassium persulfate were added over 3 hours. An aqueous dispersion of styrene / acrylic resin having a diameter of 130 nm and a solid content of 40% by mass was obtained.

The polymerization reaction proceeded stably and the polymerization conversion rate of the obtained resin was high. After the resin was separated from the aqueous resin dispersion using an ultracentrifuge, the molecular weight was measured by GPC. As a result, the weight average molecular weight (MwH) of the resin was 400,000 and Tg was 50 ° C.
Production Examples 3-7
An aqueous dispersion of styrene / acrylic resin was obtained in the same manner as in Production Example 2 except that the blending amounts of St, BA and MAA were as shown in Table 1.

[Manufacture of binder resin for toner]
Example 1
Using a continuous kneader “KRC Kneader” (trade name; manufactured by Kurimoto Steel Works), the jacket temperature was set to 200 ° C., and 60 parts by mass of the first resin of Production Example 1 (active ingredient) About 60 parts by mass), 100 parts by mass of the second resin aqueous dispersions of Production Examples 2 to 7 (about 40 parts by mass of active ingredient) and polypropylene wax “Biscol 330P” (trade name; softening point 152 ° C .; Sanyo Chemical) Kogyo Co., Ltd.) 6 parts by mass and [trade name; zinc acetate 20% aqueous solution; manufactured by Kanto Chemical Co., Ltd.] 1 part by mass of a polyvalent metal salt previously mixed continuously from separate material supply ports While adding, heating and mixing operations were performed to obtain a solvent-free binder resin for toner as a mixture.

Examples 2-11 and Comparative Examples 1-3
A binder resin for toner was obtained in the same manner as in Example 1 except that the blending amounts of the first resin, the second resin and the polyvalent metal salt were as shown in Tables 2 to 4. In Examples 4 to 11 and Comparative Example 2, the same polyvalent metal salt solution as in Example 1 was used as the polyvalent metal salt solution. In Example 2, the polyvalent metal composed of a 20% calcium acetate aqueous solution. A salt solution was used, and in Example 3, a polyvalent metal salt solution composed of a 5% aluminum chloride aqueous solution was used.

[Manufacture of magnetic toner]
100 parts by mass of solvent-free binder resin for toners of Examples 1 to 11 and Comparative Examples 1 to 3 obtained as described above, magnetite “BL-200” (trade name; manufactured by Titanium Industry Co., Ltd.) 80 2 parts by mass of azo-type iron complex “T-77” (trade name; manufactured by Hodogaya Chemical Co., Ltd.) are added to Henschel mixer “FM5C / 1” (trade name; manufactured by Mitsui Mining Co., Ltd.). After mixing, the mixture was melt-kneaded using a twin-screw kneading extruder “KRCS1 Kneader” (trade name; manufactured by Kurimoto Steel Works Co., Ltd.). After cooling, coarsely pulverize with hammer mill “VC-210” (trade name; manufactured by Horai Co., Ltd.), and then finely pulverize with jet mill “LJ-N” (trade name; manufactured by Nippon Pneumatic Industry Co., Ltd.). went. Further, the obtained finely divided powder was classified using an air classifier “MDS-2” (trade name; manufactured by Nippon Pneumatic Industry Co., Ltd.) to obtain particles of 5 to 20 μm. 1 part by mass of “TG-308F” (manufactured by Cabot Specialty Chemicals) was added and mixed to obtain a magnetic toner having an average particle size of 5 to 20 μm.

  With respect to magnetic toners (hereinafter also referred to as magnetic sample toners) obtained using the binder resins for toners of Examples 1 to 11 and Comparative Examples 1 to 3, the toner storage stability, fixing property and offset resistance are as follows. And evaluated.

◎：凝集物残存量が50％未満。
○：凝集物残存量が50％以上70％未満。
△：凝集物残存量が70％以上90％未満。
×：凝集物残存量が90％以上
(1-1) Toner storability Magnetic toner is placed in a 100 ml polyethylene bottle, sealed, and allowed to stand at 50 ° C. for 16 hours. ), The sample is placed on a sieve with an opening of 350 μm and vibrated to obtain the residual amount on the sieve. The residual amount of toner aggregate is obtained by the following formula, and the following evaluation is performed based on this value. It was. The results are shown in Tables 2-4.

A: Aggregate residual amount is less than 50%.
○: Aggregate residual amount is 50% or more and less than 70%.
Δ: Aggregate residual amount is 70% or more and less than 90%.
×: Aggregate remaining amount is 90% or more

○：定着率95％以上。
△：定着率90％以上95％未満。
×：定着率90％未満。
(1-2) Fixability test Set the temperature of the image fixing unit to 200 ° C and perform continuous printing of 5 sheets. On the surface of the 5th sheet, the Scotch Mending tape [trade name; manufactured by Sumitomo 3M Ltd.] ] 1mm disk of 16mm thick circumferential part abut and reciprocate once, peel off the mending tape, and the image density before and after the tape is applied to Macbeth Using a reflection densitometer [trade name; manufactured by Macbeth Coulter, Inc.], the print adhesion of the magnetic sample toner to plain paper is determined as The street was evaluated. The results of image density and print adhesion are shown in Tables 2-4. In Tables 2 to 4, “◯” was accepted as being excellent in fixability, and “Δ” and “x” were rejected as being not excellent in fixability.

○: Fixing rate of 95% or more.
Δ: Fixing rate of 90% or more and less than 95%.
X: Fixing rate is less than 90%.

(1-3) Offset resistance test Set the temperature of the image fixing unit to 200 ° C and perform continuous printing of 5 sheets, then print blank paper, and check the degree of dirt on the white paper and the heating roll due to toner offset. By visually observing, the offset resistance was evaluated according to the following criteria. The results are shown in Tables 2-4. In addition, “◯” was accepted as being excellent in offset resistance, and “Δ” and “x” were rejected as being inferior in offset resistance.

○: No dirt on both the white paper and the heating roll.
Δ: There is no stain on the white paper, but a slight stain is observed on the heating roll.
X: Dirt is recognized on white paper.

[Production of non-magnetic toner]
Magnetite “BL-200” (trade name; manufactured by Titanium Industry Co., Ltd.) Instead of using 80 parts by mass, non-magnetic toner is the same as magnetic toner except that 6 parts by mass of carbon black “MA-100” was used. Got.

  With respect to the nonmagnetic toners (hereinafter also referred to as nonmagnetic sample toners) obtained using the binder resins for toners of Examples 1 to 11 and Comparative Examples 1 to 3, the toner storage stability, fixing property, and offset resistance are as follows. It evaluated as follows.

(2-1) Toner storability Evaluation of the storability of the non-magnetic toner was carried out in the same manner as “(1-1) Toner storability” for the magnetic toner. The results are shown in Tables 2-4.

(2-2) Fixability test Same as the method of “(1-2) Fixability test” except that the temperature of the image fixing unit is set to 200 ° C. and the 1000th print is used after continuous printing. Tests were conducted to determine the value of the fixing ratio of printing by the same mathematical formula, and the printing adhesion of the nonmagnetic sample toner to plain paper was evaluated according to the same evaluation criteria. The results of image density and print adhesion are shown in Tables 2-4.

(2-3) Offset resistance test Same as “(1-3) Offset resistance test” except that the temperature of the image fixing unit is set to 200 ° C. and 1000 sheets are continuously printed and then white paper is printed. The offset resistance was evaluated. The results are shown in Tables 2-4.

  From the results of Tables 2 to 4, Examples 1 to 11 passed in both points of fixability and offset resistance, whereas in Comparative Examples 1 to 3, out of fixability and offset resistance. It turned out that it was disqualified at any point.

  From the above, it has been found that according to the method for producing a binder resin for toner of the present invention, it is possible to produce a toner binder resin capable of imparting excellent fixability and offset resistance to the toner.

Claims (9)

A first resin, a second resin having a weight average molecular weight greater than that of the first resin and containing a carboxyl group, and a polyvalent metal salt solution containing a polyvalent metal salt and water are charged into a mixing tank and mixed. A mixing step of preparing a mixture;
A method for producing a toner binder resin, wherein a toner binder resin is produced through a moisture removal step of removing moisture from the mixture simultaneously with and / or after the mixing step,
The same time and / or after the water removal step, the second resin was depending on the polyvalent metal ion crosslinking derived from the polyvalent metal salts, polyvalent metal derived from the first resin to the polyvalent metal salt Including a crosslinking step that is not crosslinked by ions,
The method for producing a binder resin for toner , wherein the polyvalent metal salt is contained in the mixture so as to have a ratio of 0.5 to 2.1 parts by mass with respect to 100 parts by mass of the second resin . A first resin, a second resin having a weight average molecular weight greater than that of the first resin and containing a carboxyl group, and a polyvalent metal salt solution containing a polyvalent metal salt and water are charged into a mixing tank and mixed. A mixing step of preparing a mixture;
  A method for producing a toner binder resin, wherein a toner binder resin is produced through a moisture removal step of removing moisture from the mixture simultaneously with and / or after the mixing step,
  Simultaneously and / or after the moisture removing step, the second resin is cross-linked with a polyvalent metal ion derived from the polyvalent metal salt, and the first resin is derived from the polyvalent metal salt. Including a crosslinking step that is not crosslinked by
  A method for producing a binder resin for toner, wherein the first resin and the second resin are composed of a styrene polymer. 3. The method for producing a binder resin for toner according to claim 1, wherein, in the mixing step, the second resin and the polyvalent metal salt solution are put into the mixing tank in a mixed state. The manufacturing method according to any one of claims 1 to 3 , wherein in the mixing step, the second resin is charged into the mixing tank in the form of an aqueous dispersion. 3. The toner bond according to claim 2, wherein the polyvalent metal salt is contained in the mixture in a ratio of 0.5 to 2.1 parts by mass with respect to 100 parts by mass of the second resin. A method for producing a resin. The method for producing a binder resin for toner according to any one of claims 1 to 5 , wherein the polyvalent metal salt is composed of a divalent metal salt. The method for producing a binder resin for toner according to claim 6 , wherein the divalent metal salt is composed of at least one selected from the group consisting of a zinc salt and a calcium salt.   The binder for toner according to any one of claims 1 to 7, wherein a blending ratio of the first resin in a total of 100% by mass of the first resin and the second resin is in a range of 50 to 80% by mass. Manufacturing method of resin. A preparation step of preparing a binder resin for toner by the method for producing a binder resin for toner according to any one of claims 1 to 8,
A method for producing a toner, comprising: a colorant mixing step of mixing the binder resin for toner prepared in the preparation step and a colorant to obtain a toner.