JP5043371B2 - Method for producing toner for electrophotography - Google Patents

Description

  The present invention relates to an electrophotographic toner used for developing a latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method, and the like, and a method for producing the electrophotographic toner.

  In recent years, demand for on-demand printing has increased, and there has been a demand for a toner that can cope with higher image quality and higher speed, and that has higher reliability. Therefore, conventionally, from the viewpoint of durability and fixability, a toner using a resin obtained by using a raw material monomer of a polyester containing an alcohol component and a carboxylic acid component and a raw material monomer of an addition polymerization resin containing styrene has been reported. (See Patent Document 1).

On the other hand, the demand for safety of the binder resin for toner is increasing year by year. Further, odor when exposed to high temperatures in melt kneading at the time of toner production and melt fixing at the time of toner use is regarded as a problem. From these viewpoints, various methods for reducing the residual monomer amount in the binder resin have been studied. For example, there is a method of using a polymerization initiator having a different half-life (see Patent Documents 2 and 3).
Japanese Patent Laid-Open No. 10-87839 Japanese Patent Laid-Open No. 7-120971 JP 7-49588 A

  However, the above method is insufficient in the effect of reducing the residual monomer amount, and increases the reaction time, changes in the resin molecular weight distribution, and makes it difficult to adjust various physical properties. Furthermore, there is a concern about odor due to the residue of the polymerization initiator. For this reason, there is a demand for the development of a toner that has a small influence on the physical properties and characteristics of the resin and has a reduced amount of residual styrene in the resin, which is a problem of safety and odor.

  An object of the present invention is to provide a toner for electrophotography in which the amount of residual styrene in the resin is reduced, which has a small influence on the physical properties and characteristics of the resin and causes problems of safety and odor, and a method for producing the same.

The present invention
[1] An electrophotographic toner obtained by a method including a step of melt-kneading a toner material containing a binder resin with a continuous open roll kneader, wherein the binder resin is a condensation polymerization resin. A composite resin obtained by polymerizing a raw material monomer and an addition polymerization resin raw material monomer containing styrene, and containing 40 to 100% by weight of a composite resin having a styrene content of 3 to 100 ppm in a binder resin, The method for producing an electrophotographic toner according to the above [1], comprising a step of melt-kneading a toner material containing a photographic toner and [2] a binder resin with a continuous open roll kneader, When the effective kneading length of the continuous open roll type kneader is L, the average temperature (T1) of the toner material in the range from 0.5 L to 1.0 L from the toner material supply port toward the kneaded product discharge port side , The difference of the roll set maximum temperature of kneader (T2) (T2-T1) is the formula (1):
5 ≦ T2-T1 ≦ 80
The present invention relates to a method for producing an electrophotographic toner that satisfies the above.

  The toner for electrophotography of the present invention has an excellent effect that the amount of residual styrene in the resin is reduced and has little influence on the physical properties and properties of the resin. An electrophotographic toner can be obtained in which the amount of residual styrene is reduced and the effect on the physical properties and characteristics of the resin is small.

  The electrophotographic toner of the present invention is an electrophotographic toner obtained by a method comprising a step of melt-kneading a toner raw material containing a binder resin with a continuous open roll kneader, wherein the binder resin comprises: A composite resin obtained by polymerizing a raw material monomer of a condensation polymerization resin and a raw material monomer of an addition polymerization resin containing styrene, containing 40 to 100% by weight of the composite resin having a styrene content of 3 to 100 ppm in the binder resin. There is a feature. Conventionally, in order to reduce the amount of residual styrene, attempts have been made to melt and knead the toner at a high temperature at the time of toner melting and kneading. However, at a high temperature, the phenomenon of increasing the amount of residual styrene is caused by the decomposition of the resin (polymer). Result. That is, in order to volatilize styrene, it is necessary to raise the temperature, but in order to suppress the decomposition of the polymer, it is necessary to lower the temperature.

  The present invention has been made to realize two conflicting events from the above viewpoint. That is, in the present invention, by melting and kneading the toner raw material in a continuous open roll type kneader that is an open type kneader, the styrene contained and / or generated in the resin can be scattered to some extent, In addition, it has been found that polymer decomposition can be minimized by kneading at a low temperature.

  In the present invention, examples of the polycondensation resin component in the composite resin include polyester, polyamide, polyester / polyamide, and the like, and polyester is preferable from the viewpoint of easy binding of a reaction product of water and styrene.

  The polyester is not particularly limited, and can be obtained by polycondensing a raw material monomer containing an alcohol component composed of a divalent or higher alcohol and a carboxylic acid component composed of a divalent or higher carboxylic acid compound.

  As the dihydric or higher alcohol, from the viewpoint of storage stability of the toner, the formula (I):

(In the formula, RO is an alkylene oxide, R is an alkylene group having 2 or 3 carbon atoms, x and y are positive numbers indicating the average added mole number of alkylene oxide, and the sum of x and y is 1 to 16) (Preferably 1.5 to 5)
An alkylene oxide adduct of bisphenol A represented by The content of the alkylene oxide adduct of bisphenol A is preferably 40 mol% or more, more preferably 60 mol% or more, and still more preferably 80 mol% or more in the alcohol component.

  Examples of the alkylene oxide adduct of bisphenol A represented by the formula (I) include polyoxyethylene-2,2-bis (4-hydroxyphenyl) propane and other ethylene oxide adducts having 2 carbon atoms, such as polyoxypropylene Examples thereof include propylene oxide adducts having 3 carbon atoms such as -2,2-bis (4-hydroxyphenyl) propane.

  The alcohol components other than the alkylene oxide adduct of bisphenol A include ethylene glycol, 1,2-propylene glycol, 1,4-butanediol, neopentyl glycol, polyethylene glycol, polypropylene glycol, bisphenol A, hydrogenated bisphenol A, and sorbitol. , Pentaerythritol, glycerol, trimethylolpropane and the like.

  Examples of the divalent or higher carboxylic acid compound include adipic acid, fumaric acid, maleic acid, succinic acid (for example, n-dodecenyl succinic acid, isododecenyl succinic acid, n-dodecyl succinic acid, isooctenyl succinic acid, Aliphatic carboxylic acids such as isooctyl succinic acid and the like, succinic acid substituted with alkyl groups having 1 to 20 carbon atoms or alkenyl groups having 2 to 20 carbon atoms, phthalic acid, isophthalic acid, terephthalic acid, 1,2, 4-Benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, aromatic carboxylic acids such as pyromellitic acid, anhydrides of these acids and lower alkyl (C1-3) esters, etc. Is mentioned. Such acids, anhydrides of these acids, and alkyl esters of these acids are collectively referred to herein as carboxylic acid compounds.

  The polyester is preferably a crosslinked polyester obtained using a trivalent or higher monomer as the alcohol component and / or carboxylic acid component from the viewpoint of the softening point and grindability. The content of the trivalent or higher monomer is preferably 2 to 20 mol%, more preferably 4 to 18 mol% in the total amount of the alcohol component and the carboxylic acid component. As the trivalent or higher monomer, 1,2,4-benzenetricarboxylic acid (trimellitic acid) and its anhydride are preferable.

  The alcohol component may contain a monovalent alcohol, and the carboxylic acid component may contain a monovalent carboxylic acid compound as appropriate from the viewpoints of molecular weight adjustment and offset resistance improvement.

  The polycondensation of the alcohol component and the carboxylic acid component can be performed, for example, in an inert gas atmosphere at a temperature of 180 to 250 ° C. using an esterification catalyst if necessary.

  On the other hand, as a raw material monomer for addition polymerization resins, styrene compounds such as styrene and α-methylstyrene; ethylenically unsaturated monoolefins such as ethylene and propylene; diolefins such as butadiene; halovinyls such as vinyl chloride; Vinyl esters such as vinyl acetate and vinyl propionate; alkyl (1 to 18 carbon atoms) esters of (meth) acrylic acid, esters of ethylenic monocarboxylic acids such as dimethylaminoethyl (meth) acrylate; vinyl methyl ether, etc. Vinyl ethers of vinylidene; vinylidene halides such as vinylidene chloride; N-vinyl compounds such as N-vinylpyrrolidone and the like. Among these, in addition to styrene, the viewpoint of stability and ease of control of the polymerization reaction From the above, esters of ethylenic monocarboxylic acids are preferred, alkyl (meth) acrylic acid ( C1-C18) esters are more preferred. The content of styrene is preferably 30 to 95% by weight, more preferably 60 to 90% by weight, in the raw material monomer of the addition polymerization resin.

  The content of the ester of ethylenic monocarboxylic acid is preferably 5 to 70% by weight, more preferably 10 to 40% by weight in the addition polymerization resin monomer from the viewpoint of storage stability.

  Furthermore, the total content of esters of styrene and ethylenic monocarboxylic acid is preferably 70% by weight or more, more preferably 80% by weight or more, and still more preferably 90% by weight or more in the addition polymerization resin monomer.

  The monomer ratio of styrene to the ester of ethylenic monocarboxylic acid (styrene / ethylenic monocarboxylic acid ester) is preferably 50/50 to 95/5, more preferably 70/30 to 95/5.

  In addition, a polymerization initiator, a crosslinking agent, or the like may be used as necessary for the addition polymerization of the raw material monomer of the addition polymerization resin.

  The addition polymerization reaction can be performed by a conventional method, for example, in the presence of a polymerization initiator, a crosslinking agent, or the like, in the presence of an organic solvent or in the absence of a solvent. For example, the temperature condition is preferably 110 to 200 ° C., More preferably, it is 140-170 degreeC.

  Examples of the organic solvent used in the addition polymerization reaction include xylene, toluene, methyl ethyl ketone, and acetone. The amount of the organic solvent used is preferably about 10 to 50 parts by weight with respect to 100 parts by weight of the addition polymerization resin monomer.

  In the present invention, from the viewpoint of easy control of the content of a small amount of styrene, in addition to the raw material monomer of the condensation polymerization resin and the raw material monomer of the addition polymerization resin, the composite resin further includes the raw material monomer of the condensation polymerization resin. And a resin (hybrid resin) obtained by using a compound capable of reacting with any of the raw material monomers of the addition polymerization resin (a bireactive monomer). In the hybrid resin, the condensation polymerization resin component and the addition polymerization resin component are partially bonded via the both reactive monomers, and the addition polymerization resin component is more finely and uniformly contained in the condensation polymerization resin component. Is distributed.

  As the both reactive monomers, at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an epoxy group, a primary amino group and a secondary amino group in the molecule, and an ethylenically unsaturated bond A compound having the above formula is preferred, and by using such a bireactive monomer, the dispersibility of the resin to be the dispersed phase can be further improved. Specific examples of the both reactive monomers include, for example, acrylic acid, fumaric acid, methacrylic acid, citraconic acid, maleic acid, 2-hydroxyethyl (meth) acrylate, glycidyl (meth) acrylate, and carboxylic acids thereof. Derivatives such as anhydrides, alkyl (1 to 2 carbon atoms) esters and the like can be mentioned, and among these, acrylic acid, methacrylic acid, fumaric acid, maleic acid and derivatives of these carboxylic acids are preferable from the viewpoint of reactivity.

  In the present invention, among both reactive monomers, a monomer having two or more functional groups (polycarboxylic acid or the like) and a derivative thereof as a raw material monomer for the polyester unit, a monomer having one functional group (monocarboxylic acid or the like) and The derivative is treated as a raw material monomer for the addition polymerization resin unit. The amount of both reactive monomers used is a condensation polymerization resin monomer for monomers having two or more functional groups and derivatives thereof, and an addition polymerization resin monomer for monomers having one functional group and derivatives thereof. Among these, 1-10 mol% is preferable respectively, and 4-8 mol% is more preferable.

  In the present invention, the composite resin is obtained by performing the condensation polymerization reaction and the addition polymerization reaction in parallel in the same reaction vessel, but the progress and completion of the condensation polymerization reaction and the addition polymerization reaction are simultaneous in time. It is not necessary, and the reaction temperature and time may be appropriately selected according to each reaction mechanism to advance and complete the reaction. The condensation polymerization reaction and the addition polymerization reaction can be performed by the above-described methods.

  Moreover, a composite resin can be manufactured through the below-mentioned process (A) and (B) from a viewpoint of reducing the amount of residual styrene efficiently.

  That is, the step (B) of mixing the reaction mixture produced in step (A) with water after and / or after the steps (A) and (A) of subjecting the addition polymerization resin monomer containing styrene to an addition polymerization reaction (B ), And at least at any point before, during and after step (A) and step (B), a step (C) in which a polyester monomer is further present in the reaction system and subjected to a condensation polymerization reaction. It can also be obtained.

  The mixing amount of water is preferably 0.1 to 50 parts by weight, more preferably 0.5 to 40 parts by weight with respect to 100 parts by weight of the addition polymerization resin monomer, from the viewpoint of controlling the influence on the physical properties of the resin. More preferred is ~ 35 parts by weight.

  The temperature in the system when mixing the reaction mixture produced in step (A) and water is preferably 100 to 300 ° C, more preferably 130 to 250 ° C, from the viewpoint of the evaporation efficiency of water and the viscosity of the reaction mixture. 150 to 240 ° C. is more preferable.

  The method of contacting and / or mixing the reaction mixture produced in step (A) and / or water is not particularly limited, but water is added dropwise to the reaction mixture from the viewpoint of efficiently adjusting the amount of styrene due to the azeotropic effect with water. Or a method of adding steam is preferable. Although water evaporates after mixing, the water content in the resin is preferably 0.2% by weight or less from the viewpoint of the charging characteristics of the toner. A method for reducing the water content is 100 ° C. or higher after completion of water mixing. A method of holding or removing by reduced pressure is preferable.

  The step (A) and the step (B) do not have to be performed separately, and both steps may be partially performed in parallel. Therefore, the timing of mixing the reaction mixture and water may be after the addition polymerization reaction in step (A) or in the middle of the addition polymerization reaction. From the viewpoint of mixing properties, it is preferable to add water after the addition polymerization reaction in step (A) is completed. The progress of the addition polymerization reaction can be predicted and confirmed from the half-life of the initiator used, the heat of reaction, and the like.

As a procedure of the process in the manufacturing method of the composite resin,
i) a method of performing the step (A) after the step (C) of performing the condensation polymerization reaction;
ii) The step (C) for conducting the polycondensation reaction is started prior to the step (A), and after the step (A), the reaction temperature is increased again, and if necessary, a trivalent or higher polycondensation that becomes a crosslinking agent is performed. A method in which a polymerization resin monomer is added to the polymerization system, and the condensation polymerization reaction in the step (C) is further advanced,
iii) The step (A) for carrying out the addition polymerization reaction under the temperature conditions suitable for the addition polymerization reaction and the step (C) for carrying out the condensation polymerization reaction are carried out in parallel, and the reaction temperature is maintained under the above conditions. ) Is completed, the reaction temperature is increased, and if necessary, a tri- or higher polycondensation resin monomer serving as a cross-linking agent is added to the polymerization system to further advance the polycondensation reaction in step (C). Method,
Etc. In these methods, the step (B) may be performed after the start of the step (A) as described above, but is preferably after the end of the step (A), and the steps (A) and (C) More preferably after the end of). In the method iii), when the step (A) and the step (C) are performed in parallel, the addition polymerization resin monomer is contained in the mixture containing the condensation polymerization resin monomer. It is preferable that the mixture is dropped and reacted. In this way, a composite resin in which two types of resin components are effectively mixed and dispersed can be obtained by a method in which two independent polymerization reactions proceed in parallel in a reaction vessel.

  Also, when the composite resin is a hybrid resin obtained by using an amphoteric monomer, the amphoteric monomer is used together with a raw material monomer for a condensation polymerization resin and / or a raw material monomer for an addition polymerization resin, preferably an addition monomer. It can be obtained through the above-mentioned steps (A) to (C) by using together with the raw material monomer of the polymerization resin.

  In the present invention, the weight ratio of the condensation polymerization resin to the addition polymerization resin, that is, the weight ratio of the condensation polymerization resin raw material monomer to the addition polymerization resin raw material monomer (condensation polymerization resin raw material monomer / addition polymerization resin). The raw material monomer) is preferably 55/45 to 95/5, more preferably 60/40 to 95/5, since the continuous phase is preferably a condensation polymerization resin and the dispersed phase is an addition polymerization resin. 70/30 to 90/10 is more preferable.

  From the viewpoint of improving the dispersibility of the wax, the composite resin is preferably a resin obtained by polymerizing the raw material monomer of the condensation polymerization resin and the raw material monomer of the addition polymerization resin containing styrene in the presence of the wax. .

  Examples of the wax include aliphatic hydrocarbon waxes such as low molecular weight polypropylene, low molecular weight polyethylene, low molecular weight polypropylene polyethylene copolymer, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax, and oxides thereof, carnauba wax, and montan wax. , Ester waxes such as sazol wax and their deoxidized wax, fatty acid amides, fatty acids, higher alcohols, fatty acid metal salts, etc., among these, from the viewpoint of releasability and stability, Aliphatic hydrocarbon waxes are preferred.

  The amount of the wax added is preferably 20 parts by weight or less, and more preferably 10 parts by weight or less with respect to 100 parts by weight of the total amount of resin monomers used in the production of the binder resin.

  The addition timing of the wax is not particularly limited, and may be at the beginning of the polymerization or in the middle of the polymerization reaction.

  The styrene content in the composite resin is 3 to 100 ppm, preferably 10 to 85 ppm, more preferably 15 to 70 ppm from the viewpoint of suppressing odor. In particular, the composite resin obtained by the above method is a resin in which the amount of styrene in the resin is efficiently reduced. In addition, in this specification, content of styrene is measured by the method as described in the below-mentioned Example.

  From the viewpoint of wax dispersibility, the composite resin obtained by the above is contained in the binder resin in an amount of 40 to 100% by weight, preferably 70 to 100% by weight, more preferably 90 to 100% by weight, and still more preferably substantially. Therefore, it is desirable to contain 100%.

  The toner of the present invention may further contain other binder resin such as epoxy resin, polycarbonate, polyurethane, styrene-acrylic resin, and the like within a range not impairing the effects of the present invention.

  From the viewpoint of suppressing odor, the styrene content in the binder resin is preferably 3 to 100 ppm, more preferably 10 to 85 ppm, and even more preferably 15 to 70 ppm. In the present specification, the content of styrene is measured by the method described in Examples described later.

  The softening point of the binder resin is preferably 70 to 170 ° C., more preferably 80 to 150 ° C., further preferably 80 to 140 ° C., and more preferably 90 to 90 ° C. from the viewpoints of low-temperature fixability, fixable area, and storage stability. 130 ° C. The glass transition point is preferably 40 to 80 ° C., and the acid value is preferably 1 to 20 mg KOH / g. In the present specification, the softening point, glass transition point, and acid value are measured by the methods described in the examples described later.

  The toner of the present invention further includes a colorant, a release agent, a charge control agent, a magnetic powder, a fluidity improver, a conductivity modifier, an extender pigment, a reinforcing filler such as a fibrous substance, an antioxidant, and an aging agent. Additives such as an inhibitor and a cleaning property improver may be appropriately contained.

  As the colorant, dyes and pigments used as toner colorants can be used. Carbon black, phthalocyanine blue, permanent brown FG, brilliant first scarlet, pigment green B, rhodamine-B base, solvent red 49, Solvent Red 146, Solvent Blue 35, Quinacridone, Carmine 6B, Disazo Yellow, etc., and these can be used alone or in admixture of two or more. Either toner or full color toner may be used. The content of the colorant is preferably 1 to 40 parts by weight and more preferably 2 to 10 parts by weight with respect to 100 parts by weight of the binder resin.

  Examples of the release agent include those described above. Among these, aliphatic hydrocarbon waxes and ester waxes are preferable from the viewpoint of releasability and stability, and these may be contained alone or in admixture of two or more. The content of the release agent is preferably 0.1 to 20 parts by weight and more preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the binder resin. From the viewpoint of improving dispersibility, the release agent may be used together with the resin raw material monomer during the production of the binder resin, and may be internally added to the binder resin.

  As the charge control agent, any one of negative chargeability and positive chargeability can be used. Examples of the negatively chargeable charge control agent include metal-containing azo dyes, copper phthalocyanine dyes, metal complexes of salicylic acid alkyl derivatives, and nitroimidazole derivatives. Examples of the positively chargeable charge control agent include nigrosine dyes, triphenylmethane dyes, quaternary ammonium salt compounds, polyamine resins, and imidazole derivatives. Also, a polymer type such as a resin can be used. The blending amount of the charge control agent is preferably 0.1 to 8 parts by weight and more preferably 0.2 to 5 parts by weight with respect to 100 parts by weight of the binder resin from the viewpoint of chargeability.

  The toner of the present invention can be obtained by a method including a step of melt kneading a toner raw material containing a binder resin or the like with a continuous open roll kneader. In melt kneading, it is preferable that toner raw materials such as a binder resin are uniformly mixed and then supplied to an open roll kneader.

  The mixing of the toner raw materials may be a method in which all the raw materials such as the binder resin are mixed at once, or a method in which the toner raw materials are divided and mixed.

  Examples of the mixer used for mixing the toner raw material include a Henschel mixer and a super mixer. From the viewpoint of dispersibility, a Henschel mixer is preferable.

  In the melt kneading of the toner raw material, by using a continuous open roll type kneader equipped with a supply port and a kneaded material discharge port provided along the axial direction of the roll, the kneading is repeated and a dispersion aid is used. Even without this, the release agent can be efficiently highly dispersed.

  The toner raw material mixture may be supplied to the kneader from one supply port, or may be divided and supplied to the kneader from a plurality of supply ports. Is preferably supplied to the kneader from one supply port.

  The continuous open roll type kneader means an open type melt kneading part, and can easily dissipate the kneading heat generated during melt kneading. The continuous open roll type kneader used in the present invention is desirably a kneader provided with at least two rolls, preferably two rolls of a heating roll and a cooling roll. In the present invention, from the viewpoint of dispersibility, it is desirable that the heating roll is a high rotation roll and the cooling roll is a low rotation roll.

  The two rolls may be arranged in parallel, but from the viewpoint of melting and kneading the toner raw material composition and the recovered fine powder while further reducing the kneading share and preventing resin molecular cutting, etc., and on the recovered fine powder roll From the viewpoint of extending the residence time at the kneaded product and uniformly dispersing the roll, the roll clearance at the end of the kneaded product discharge port is preferably arranged to be wider than the roll clearance at the end of the supply port. Specifically, the roll gap at the end of the kneaded product supply port side is preferably 0.05 to 2 mm, more preferably 0.05 to 1 mm, further preferably 0.05 to 0.8 mm, and the roll gap at the end of the kneaded product discharge port side is 0.1 to 2 mm is preferable, 0.3 to 1.5 mm is more preferable, and 0.5 to 1 mm is more preferable.

  The structure, size, material, etc. of the roll are not particularly limited, and the roll surface may be any of smooth, corrugated, uneven, etc., but in order to increase the kneading share, a plurality of roll surfaces are provided on the surface of each roll. It is preferable that the spiral groove is cut.

  The temperature of the roll can be adjusted by, for example, the temperature of the heat medium passed through the inside of the roll, and each roll may be divided into two or more and the heat medium having different temperatures may be passed through each roll.

  The set temperature on the heating roll, particularly on the supply port side, is preferably higher than any of the softening point of the binder resin and the melting point of the release agent, and 0 to 80 ° C. higher than the higher temperature. Higher is more preferable, and higher by 5 to 50 ° C. is further preferable. The set temperature on the cooling roll, particularly on the supply port side, is preferably lower than the softening point temperature of the binder resin.

That is, when the kneading effective length of the kneading machine is L, the average temperature (T1) of the toner material kneaded in the range of 0.5 L to 1.0 L from the toner material supply port toward the kneaded product discharge port side. The preset maximum temperature (T2) of the roll of the kneader is the following formula (1):
5 ≦ T2-T1 ≦ 80
It is preferable to satisfy the formula (2):
7 ≦ T2-T1 ≦ 65
It is more preferable to satisfy the formula (3):
10 ≦ T2-T1 ≦ 50
It is further preferable to satisfy

  The average temperature (T1) of the toner raw material is a value obtained by measuring the temperature at each position of the roll during melt kneading of the toner raw material and calculating the average value of the obtained measured values. The set maximum temperature (T2) of the roll indicates the set temperature on the raw material supply port side of the roll, and when two or more rolls are used, the highest set temperature is indicated. T1 is preferably 70 ° C to 125 ° C, more preferably 80 ° C to 120 ° C, further preferably 90 ° C to 110 ° C, from the viewpoint of suppressing the generation of styrene during kneading, and the temperature difference between T1 and T2 is: It can adjust by adjusting the peripheral speed of a roll and the width | variety between rolls suitably. In this specification, the average temperature of the toner raw material is measured by the method described in Examples described later.

  The peripheral speed of the heating roll is preferably 2 to 100 m / min. The peripheral speed of the cooling roll is preferably 2 to 100 m / min, more preferably 4 to 60 m / min, and further preferably 4 to 50 m / min. The two rolls preferably have different peripheral speeds, and the ratio of the peripheral speeds of the two rolls (cooling roll / heating roll) is preferably 1/10 to 9/10, ˜8 / 10 is more preferable.

  The toner of the present invention can be produced by melting, kneading, cooling, pulverizing, and classifying as described above. Furthermore, it can also obtain through the process of surface-treating with an external additive as needed. The surface treatment is preferably performed by externally adding an external additive such as a fluidity improver such as hydrophobic silica to the toner surface with a mixer such as a Henschel mixer. External additives include known fine particles such as silica fine particles, titanium fine particles, alumina fine particles, cerium oxide fine particles, carbon black and other inorganic fine particles, and polymer fine particles such as polycarbonate, polymethyl methacrylate and silicone resin. Can be used.

  The styrene content in the toner of the present invention is preferably 3 to 100 ppm, more preferably 10 to 70 ppm, and still more preferably 15 to 50 ppm from the viewpoint of suppressing odor. In addition, in this specification, content of styrene is measured by the method as described in the below-mentioned Example.

The volume median particle size (D ₅₀ ) of the toner of the present invention is preferably 2 to 15 μm, more preferably 2 to 10 μm, further preferably 2.5 to 7 μm, and further preferably 2.5 to 6 μm from the viewpoint of image quality and chargeability. . In the present specification, the volume median particle size (D ₅₀ ) means a particle size at which the cumulative volume frequency calculated by the volume fraction is 50% when calculated from the smaller particle size.

  The toner of the present invention can be used as a one-component developing toner as it is or as a two-component developer by mixing with a carrier.

[Softening point of resin]
Using a flow tester (Shimadzu Corporation, CFT-500D), a 1 g sample was heated at a heating rate of 6 ° C / min, and a load of 1.96 MPa was applied by a plunger and extruded from a nozzle with a diameter of 1 mm and a length of 1 mm. . The amount of plunger drop of the flow tester is plotted against the temperature, and the temperature at which half of the sample flows out is taken as the softening point.

[Glass transition point of resin]
Using a differential scanning calorimeter (Seiko Denshi Kogyo Co., Ltd., DSC210), the temperature was raised to 200 ° C, and the sample was cooled to 0 ° C at a temperature drop rate of 10 ° C / min. The temperature at the intersection of the extended line of the baseline below the maximum peak temperature of endotherm and the tangent line indicating the maximum slope from the peak rising portion to the peak apex.

[Acid value of the resin]
Measured according to the method of JIS K0070. However, only the measurement solvent was changed from the mixed solvent of ethanol and ether specified in JIS K0070 to the mixed solvent of acetone and toluene (acetone: toluene = 1: 1 (volume ratio)).

[Melting point of release agent]
Using a differential scanning calorimeter (Seiko Denshi Kogyo Co., Ltd., DSC210), the temperature was raised to 200 ° C, and the sample was cooled to 0 ° C at a temperature drop rate of 10 ° C / min. The maximum peak temperature of heat of fusion is taken as the melting point.

[Volume-median particle size of toner (D ₅₀ )]
Measuring machine: Coulter Multisizer II (Beckman Coulter, Inc.)
Aperture diameter: 100μm
Analysis software: Coulter Multisizer AccuComp version 1.19 (Beckman Coulter)
Electrolyte: Isoton II (Beckman Coulter, Inc.)
Dispersion: Emulgen 109P (manufactured by Kao Corporation, polyoxyethylene lauryl ether, HLB: 13.6) is dissolved in the electrolytic solution to a concentration of 5% by weight to obtain a dispersion.
Dispersion conditions: 10 mg of a measurement sample is added to 5 mL of the above dispersion, and dispersed for 1 minute with an ultrasonic disperser, then 25 mL of electrolyte is added, and further dispersed for 1 minute with an ultrasonic disperser. Prepare a dispersion.
Measurement conditions: By adding the sample dispersion to 100 mL of the electrolytic solution, the particle size of 30,000 particles is adjusted to a concentration that can be measured in 20 seconds, and then 30,000 particles are measured, Determine the volume-median particle size (D ₅₀ ).

[Average dispersion diameter of release agent]
(1) A toner embedded with an epoxy resin is made into a thin section having a thickness of about 100 nm in a frozen state, and the major axis and minor axis of the release agent dispersed in the toner are measured using a transmission electron microscope.
(2) The domain diameter of the release agent is determined from the values of the major axis and the minor axis. The domain diameter is obtained from the formula of (major axis + minor axis) / 2.
(3) 50 domain diameters of the release agent dispersed in the toner are measured by the methods of (1) and (2), and the value of the obtained domain diameter (D _p ) is expressed by the following formula:

A value obtained by substituting (where n _p is the number of dispersed particles having a domain diameter of D _p ) is defined as an average dispersed diameter.

[Styrene content]
The styrene content is measured by the following method using TD-GC / MS (thermal desorption-gas chromatograph mass spectrometer).
(1) Measuring equipment
TD: Turbo Matrix ATD (Automatic Heating Desorption (ATD) device, manufactured by Perkin Elmer)
GC: 6890N (Agilent Technologies)
MS: 5973N (Agilent Technologies)
(2) Measurement conditions
<TD>
Use outlet split Analysis mode: 2-stage desorption Injection: 2 times Heat desorption condition from tube: 1 hour at 120 ° C Adsorption condition to trap tube: 50 minutes at -30 ° C Desorption condition from trap tube: start from -30 ° C The temperature is raised to 300 ° C at 40 ° C / min. Purge time: 1 minute Valve temperature: 150 ° C
Transfer temperature: 160 ° C
Column pressure: 150kPa
Inlet split: 50mL / min
Outlet split: 5mL / min
Desorption: 50mL / min
<GC>
Analytical column: HP5-MS (60m × 250μm × 0.25μm)
Carrier: He
Flow rate condition: 1mL / min
Inlet temperature: 250 ° C
Column pressure: 150kPa (controlled from TD)
Oven temperature condition: <temperature time (ratio)>
40 ℃ 3min
70 ℃ (2 ℃ / min)
150 ℃ (5 ℃ / min)
300 ℃ (10 ℃ / min)
<MS>
Ionization method: EI (electron ionization) method Interface temperature: 300 ° C
Ion source temperature: 230 ° C
Quadrupole temperature: 150 ° C
Detection mode: Scan (range m / z = 40-460)
Initial Area Reject: 0
Initial Peak Width: 0.097
Shoulder Detection: off
Initial Threshold: 12.0
(3) Styrene determination 5 μL of the standard “heavy toluene / methanol solution (10 mg / L)” is injected into a tube containing Tenax TA. Next, 5 mg of the sample is weighed and added to the tube. Thereafter, the tube is set in a measuring device and measurement is performed. The quantification is carried out with one check amount, the peak area is measured for the peak of mass chromatogram of m / z = 98 for heavy toluene and m / z = 104 for styrene, and the styrene concentration is determined from the obtained peak area ratio.

Resin Production Example 1 (Production Example of Resin A)
The raw material monomer of polyester monomers other than trimellitic anhydride shown in Table 1 and 40 g of tin octylate as an esterification catalyst, 4 liters of 10 liters equipped with nitrogen introduction tube, dehydration tube, stirrer and thermocouple The flask was placed in a flask and subjected to a condensation polymerization reaction at 230 ° C. until no terephthalic acid particles could be confirmed. Further, the mixture is reacted at 8 kPa for 1 hour, polyethylene wax “Paraflint H105” (manufactured by Sazol) shown in Table 1 is added, and after cooling to 160 ° C., the raw material monomers and polymerization of vinyl resin monomers shown in Table 1 The mixture of initiators was dropped over 1 hour with a dropping funnel. After dropping, the addition polymerization reaction was aged for 1 hour while maintaining at 160 ° C., then the temperature was raised to 210 ° C. and maintained at 8 kPa for 1 hour to remove the vinyl resin monomer. Thereafter, trimellitic anhydride shown in Table 1 was added, and a crosslinking reaction was performed until a predetermined softening point was reached to obtain a resin A. In the resin A, the weight ratio of polyester monomer to vinyl resin monomer (weight ratio of polyester monomer / vinyl resin monomer) is 73/17.

Resin Production Examples 2-3 (Production Examples of Resins B and C)
The raw material monomer of polyester monomers other than trimellitic anhydride shown in Table 1 and 40 g of tin octylate as an esterification catalyst, 4 liters of 10 liters equipped with nitrogen introduction tube, dehydration tube, stirrer and thermocouple The flask was placed in a flask and subjected to a condensation polymerization reaction at 230 ° C. until no terephthalic acid particles could be confirmed. Further, the mixture is reacted at 8 kPa for 1 hour, polyethylene wax “Paraflint H105” (manufactured by Sazol) shown in Table 1 is added, and after cooling to 160 ° C., the raw material monomers and polymerization of vinyl resin monomers shown in Table 1 The mixture of initiators was dropped over 1 hour with a dropping funnel. After the dropwise addition, the addition polymerization reaction was aged for 1 hour while maintaining the temperature at 160 ° C, and then the temperature was raised to 210 ° C and maintained at 8 kPa for 0.5 hours. Next, while stirring at 210 ° C. and 40 kPa, steam at 140 ° C. over 1 hour was added to the resin at a rate of 500 g (29.7 parts by weight with respect to 100 parts by weight of the total amount of addition polymerization resin monomer) / hour. Added to. Thereafter, trimellitic anhydride shown in Table 1 was added, and a crosslinking reaction was performed until a predetermined softening point was reached to obtain resins B and C. In the resins B and C, the weight ratio of polyester monomer to vinyl resin monomer (weight ratio of polyester monomer / vinyl resin monomer) is 73/17.

Resin Production Example 4 (Production Example of Resin D)
Raw material monomers other than trimellitic anhydride shown in Table 1 and 40 g of tin octylate as an esterification catalyst were placed in a 10-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple. The polycondensation reaction was carried out at 8 ° C for 8 hours. Furthermore, after reacting at 8.3 kPa for 1 hour, the mixture was cooled to 210 ° C., trimellitic anhydride shown in Table 1 was added, and the reaction was performed until the desired softening point was reached, whereby Resin D was obtained.

Examples 1-4 and Comparative Examples 1-2
The toner raw materials shown in Table 2 were stirred and mixed with a Henschel mixer and then melt-kneaded under the conditions shown in Table 2. Each condition is as described below. The obtained kneaded product was rolled and cooled with a cooling roller, then pulverized with a jet mill and classified to obtain a toner having a volume-median particle size (D ₅₀ ) of 4.5 μm. With respect to the obtained toner, the average temperature of the toner raw material, the amount of residual styrene in the resin, and the amount of residual styrene in the toner were measured, and the results are shown in Table 2.

[Kneading condition example A]
A continuous two-roll kneader having a roll outer diameter of 0.12 m and an effective roll length of 0.8 m was used. The operating conditions of the continuous two-roll kneader are as follows: high rotation side roll (front roll) peripheral speed 9m / min, low rotation side roll (back roll) peripheral speed 6m / min, roll at the end of the kneaded product supply port The gap was 0.1 mm. The heating medium temperature and cooling medium temperature in the roll were 160 ° C. on the raw material input side of the high rotation roll and 100 ° C. on the kneading discharge side, 30 ° C. on the raw material input side of the low rotation roll, and 30 ° C. on the kneaded material discharge side. The feed rate of the raw material mixture was 4 kg / hour, and the average residence time was about 10 minutes.

[Kneading condition example B]
A continuous two-roll kneader having a roll outer diameter of 0.12 m and an effective roll length of 0.8 m was used. The operating conditions of the continuous two-roll kneader are as follows: high rotation side roll (front roll) peripheral speed 9m / min, low rotation side roll (back roll) peripheral speed 6m / min, roll at the end of the kneaded product supply port The gap was 0.1 mm. The heating medium temperature and cooling medium temperature in the roll were 120 ° C. on the raw material input side of the high rotation roll and 100 ° C. on the kneading discharge side, 30 ° C. on the raw material input side of the low rotation roll, and 30 ° C. on the kneaded material discharge side. The feed rate of the mixture was 4 kg / hour, and the average residence time was about 10 minutes.

[Kneading condition example C]
A co-rotating twin screw extruder having a total length of 1560 mm, a screw diameter of 42 mm, and a barrel inner diameter of 43 mm was used for kneading. The roll peripheral speed was 8.6 m / min. The heating temperature in the roll was 100 ° C., the feed rate of the raw material mixture was 4 kg / hour, and the average residence time was about 18 seconds.

  The temperature at the time of melt kneading of the toner material is a toner at a position of 0.5 L, 0.75 L, 1.0 L from the toner material supply port to the kneaded product discharge port side using a reflection thermometer (manufactured by Keyence Corporation). The temperature at the time of melt kneading of the raw materials is measured, and the average value thereof is calculated and set as the average temperature.

  From the above results, the toners of Examples 1 to 4 had a lower amount of residual styrene in the toner than the comparative example. The toner of Example 4 having a low open roll set maximum temperature showed no significant difference in the amount of residual styrene between the composite resin and the toner. In particular, the toner of Examples 1 to 3 having a high open roll set maximum temperature was high. The residual styrene content of the toner was reduced by volatilizing the styrene contained in the composite resin. On the other hand, the toner of Comparative Example 1 with a large amount of residual styrene in the composite resin and the toner of Comparative Example 2 without using an open roll kneader had a large amount of residual styrene. Further, when an open roll type kneader was used, it was suggested that the average dispersion diameter of the wax was reduced and the dispersibility was improved.

  The electrophotographic toner of the present invention is used for developing a latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method or the like.

Claims (8)

A step of melt-kneading the toner materials comprising a binder resin in a continuous open-roller type kneader method for manufacturing a including electronic toner, the binder resin is a polycondensation resin material obtained by polymerizing raw material monomers for the addition polymerization resin containing a monomer and styrene, a composite resin styrene content is 3～100Ppm, Ri Na contain 40 to 100% by weight in the binder resin, continuous When the kneading effective length of the open roll type kneader is L, the temperature at the time of melt kneading of the toner material at positions of 0.5 L, 0.75 L, and 1.0 L from the toner material supply port toward the kneaded material discharge port side A difference (T2−T1) between the average value (T1) and the set temperature (T2) on the raw material supply port side of the roll of the kneader is expressed by the formula (1)
5 ≦ T2-T1 ≦ 80
A method for producing an electrophotographic toner that satisfies the above . The method for producing an electrophotographic toner according to claim 1, wherein the toner material has an average temperature (T1) of 70 ° C. to 125 ° C. Composite resin The method of manufacturing according to claim 1 or 2 toner for electrophotography according is a resin obtained by polymerizing the raw material monomers for an addition polymerization resin containing a raw material monomer and styrene polycondensation resin in the presence wax . The method for producing an electrophotographic toner according to any one of claims 1 to 3 , wherein the styrene content in the toner is 3 to 100 ppm. Composite resin, in any one of claims 1-4 which is a resin obtained by further polymerizing in the presence of a compound capable react with any of the raw material monomers for an addition polymerization resin containing a raw material monomer and styrene polycondensation resin A method for producing the electrophotographic toner according to claim . The step of mixing the reaction mixture produced in step (A) with water after the step (A) and (A) of the addition polymerization reaction of the raw material monomer of the addition polymerization resin containing styrene with the composite resin (B), and at least at any point before, during and after step (A) and step (B), further include a step (C) in which a polyester raw material monomer is present in the reaction system and subjected to a polycondensation reaction. The method for producing an electrophotographic toner according to claim 1, which is obtained by a process. The method for producing an electrophotographic toner according to claim 6, wherein the amount of water mixed is 0.1 to 50 parts by weight with respect to 100 parts by weight of the raw material monomer of the addition polymerization resin. The condensation polymerization resin is polyester, and the formula (I):

(In the formula, RO is an alkylene oxide, R is an alkylene group having 2 or 3 carbon atoms, x and y are positive numbers indicating the average added mole number of alkylene oxide, and the sum of x and y is 1 to 16) Is)
The method for producing a toner for electrophotography according to any one of claims 1 to 7, wherein the content of the alkylene oxide adduct of bisphenol A represented by the formula (1) is 40 mol% or more in an alcohol component which is a raw material monomer for polyester.