JP2010107675A - Electrophotographic toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide electrophotographic toner, having excellent hydrolysis resistance, low temperature fixability, hot offset resistance, preservability and durability. <P>SOLUTION: This electrophotographic toner is obtained according to a method including a process of particulating raw material containing binder resin in an aqueous medium. The binder resin contains composite resin containing condensation polymerizable resin and styrene-based resin. The condensation polymerizable resin is resin obtained by condensation polymerizing an alcohol component containing aliphatic polyhydric alcohol (alcohol A) having two or more secondary carbon atoms to which a hydroxy group is bonded and a carboxylic acid component. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrophotographic toner used in electrophotographic methods, electrostatic recording methods, electrostatic printing methods and the like.

  In recent years, with an increase in machine speed and energy saving, a toner having excellent low-temperature fixability has been demanded. Accordingly, a condensation polymerization resin using an aliphatic polyhydric alcohol has been proposed as a binder resin for toner, instead of the condensation polymerization resin obtained by using an aromatic polyhydric alcohol conventionally used.

  Patent Document 1 binds a polyester resin obtained by reacting an alcohol component containing 1,3-propanediol and a specific other polyhydric alcohol as essential components with a polybasic acid component. Disclosed is an electrostatic charge developing toner that is excellent in fixability and offset resistance, used as a resin, exhibits stable charging behavior even when continuously printed, and is excellent in durability to obtain a good high-quality image. .

  Patent Document 2 discloses that a fat having 2 to 6 carbon atoms and having a polyol component of 30 to 100 mol% is provided for the purpose of providing a toner having an excellent balance between low-temperature fixability and grindability and excellent gloss after fixing. A polyester resin for toner using a polyester resin comprising a group diol (at least a part of the aliphatic diol is 1,2-propylene glycol) and having a tetrahydrofuran-soluble component number average molecular weight of 1000 to 9500 is disclosed. Yes.

In Patent Document 3, a raw material containing a binder resin and a polyolefin wax and / or paraffin wax is formed into particles in a solution in order to provide an electrophotographic toner having excellent storage stability and durability. An electrophotographic toner obtained by a method comprising the step of: wherein the binder resin contains a resin obtained by using at least a raw material monomer of a condensation polymerization resin and a raw material monomer of an addition polymerization resin A photographic toner is disclosed.
JP 2002-169331 A JP 2006-154686 A JP 2007-206540 A

  However, the polycondensation resin obtained by using an aliphatic polyhydric alcohol is excellent in low-temperature fixability, but is insufficient in storage stability and disperses the additive by sharing as in the kneading and pulverization method. For chemical toners that cannot be used, durability due to poor dispersion of the release agent tends to deteriorate.

  Furthermore, when a toner is produced by granulating a raw material containing a polycondensation resin obtained using an aliphatic polyhydric alcohol in an aqueous medium, hydrolysis is likely to occur and storage stability and hot offset resistance are reduced. Easy to do.

  An object of the present invention is to provide an electrophotographic toner excellent in hydrolysis resistance, low-temperature fixability, hot offset resistance, storage stability and durability.

  The present invention is an electrophotographic toner obtained by a method including a step of granulating a raw material containing a binder resin in an aqueous medium, wherein the binder resin includes a condensation polymerization resin and a styrene resin. Containing a composite resin, the polycondensation resin is capable of condensing an alcohol component containing an aliphatic polyhydric alcohol (alcohol A) having two or more secondary carbon atoms to which a hydroxyl group is bonded, and a carboxylic acid component. The present invention relates to an electrophotographic toner which is a resin obtained by polymerization.

  The toner for electrophotography of the present invention has the effect of being excellent in hydrolysis resistance, low-temperature fixability, hot offset resistance, storage stability and durability.

  The present invention relates to an electrophotographic toner obtained by a method including a step of granulating a raw material containing a binder resin in an aqueous medium, wherein the binder resin includes a condensation polymerization resin and a styrene resin. A polycondensation resin containing at least an alcohol component containing an aliphatic polyhydric alcohol (alcohol A) having two or more secondary carbon atoms bonded with a hydroxyl group and a carboxylic acid component. It is characterized in that it is a resin obtained. Polycondensation-based resins obtained using aliphatic polyhydric alcohols tend to have higher ester values compared to the case of using aromatic polyhydric alcohols such as alkylene oxides of bisphenol A that are generally used. Therefore, it is effective in improving low-temperature fixability from the viewpoint of compatibility with paper, but it is thought that when the molecular skeleton is soft and the molecular weight is not increased so much, the glass transition point is not high and the storage stability is lowered. It is done. However, in the present invention, the use of the aliphatic polyhydric alcohol having the above specific structure makes it possible to improve the low-temperature fixability without impairing the storage stability. This is because the alkyl group bonded to the secondary carbon to which the hydroxyl group is bonded constrains the mobility of the molecule, and therefore has a higher glass transition point than a resin with a similar softening point. One is estimated. Furthermore, when the toner particles are formed in an aqueous medium, the reduction in molecular weight is suppressed, so that good storage stability and hot offset resistance can be maintained. This is because the aliphatic polyhydric alcohol having the above specific structure has an alkyl group at the terminal and a highly hydrophobic styrenic resin, so that the ester group is protected and the hydrolytic resistance of the polycondensation resin is reduced. This is considered to be because the degradability is improved and the reduction in molecular weight is suppressed. In addition, the durability is improved because the alkyl group is adjacent to the secondary carbon atom to which the hydroxyl group is bonded, so that the hydrophilicity in the vicinity of the ester group is suppressed and a hydrophobic styrenic resin is included. It is estimated that the dispersibility of additives such as a release agent is improved.

  In the present invention, the condensation polymerization resin uses at least an alcohol component containing an aliphatic polyhydric alcohol (alcohol A) having two or more secondary carbon atoms bonded with a hydroxyl group and a carboxylic acid component as raw material monomers. This is a resin obtained.

  Alcohol A includes 2,3-butanediol, 2,3-pentanediol, 2,4-pentanediol, 2,3-hexanediol, 3,4-hexanediol, 2,4-hexanediol, 2,5 -Hexanediol etc. are mentioned.

  The number of carbon atoms of alcohol A is preferably 4 to 8, more preferably 4 to 5, and even more preferably 4 from the viewpoint of increasing the ester value and improving the low-temperature fixability of the toner and also improving the storage stability. In addition, from the viewpoint of improving the storage stability by making the main chain skeleton of the resin rigid, an aliphatic polyhydric alcohol having one or more pairs of secondary carbon atoms in which secondary carbon atoms bonded with hydroxyl groups are adjacent to each other is more suitable. preferable. From these viewpoints, secondary carbon atoms bonded with hydroxyl groups such as 2,3-butanediol, 2,3-pentanediol, 2,3-hexanediol, and 3,4-hexanediol are adjacent to each other. An aliphatic polyhydric alcohol having 4 to 8 carbon atoms and having at least one set of carbon atoms is more preferable.

  The content of alcohol A is preferably 10 to 100 mol%, more preferably 12 to 80 mol%, and more preferably 25 to 75 mol% in the alcohol component of the condensation polymerization resin from the viewpoint of low-temperature fixability and storage stability of the toner. Is more preferable.

  The amount of alcohol A used in the condensation polymerization of the alcohol component and the carboxylic acid component is selected from the viewpoints of low-temperature fixability and storage stability of the toner, and the alcohol component other than alcohol A, which is a raw material monomer for the condensation polymerization resin. And 6-100 weight part is preferable with respect to 100 weight part of total amounts of a carboxylic acid component, 10-90 weight part is more preferable, 15-80 weight part is further more preferable.

  In the present invention, from the viewpoint of low-temperature fixability of the toner, the alcohol component of the condensation polymerization resin further contains an aliphatic diol (alcohol B) having 2 to 8 carbon atoms other than alcohol A, preferably 2 to 6 carbon atoms. It is preferable to contain. As alcohol B, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-butenediol, 1,3-butanediol, neopentyl glycol and the like can be mentioned. Among these, ethylene glycol, 1,2-propanediol and 1,3-propanediol are preferable from the viewpoint of storage stability of the toner.

  The content of the alcohol B is preferably 0 to 90 mol%, more preferably 0.5 to 90 mol%, still more preferably 20 to 88 mol%, and more preferably 25 to 75 in the alcohol component from the viewpoint of improving the low-temperature fixability of the toner. Mole% is even more preferred.

  Further, the content of the alcohol B with respect to 1 mol of the alcohol A is preferably 10 mol or less, preferably 0.1 to 5 mol, and more preferably 0.3 to 3 mol, from the viewpoint of storage stability and low-temperature fixability of the toner.

  Examples of alcohol components other than alcohol A and alcohol B include polyoxypropylene-2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene-2,2-bis (4-hydroxyphenyl) propane, I):

(In the formula, RO and OR are oxyalkylene groups, R is an ethylene and / or propylene group, x and y represent the number of added moles of alkylene oxide, each being a positive number, and the sum of x and y. 1 to 16 is preferable, 1 to 8 is more preferable, and 1.5 to 4 is more preferable)
An aromatic diol such as an alkylene oxide adduct of bisphenol represented by the formula: a trihydric or higher polyhydric alcohol such as glycerin.

  From the viewpoint of low-temperature fixability of the toner, the content of the aromatic diol is preferably 10 mol% or less, more preferably 5 mol% or less in the alcohol component, and it is preferable that the aromatic diol is not substantially used. Here, “not substantially used” means that the content is 0 mol% in the alcohol component or 1 mol% or less even if it is contained.

  Further, as the carboxylic acid component of the condensation polymerization resin, a dicarboxylic acid compound or a trivalent or higher polyvalent carboxylic acid compound can be used.

  Dicarboxylic acid compounds include aliphatic acids such as oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, alkyl succinic acid and alkenyl succinic acid. Dicarboxylic acids; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid; and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. In the present invention, the above-mentioned acids, anhydrides of these acids, and alkyl esters of the acids are collectively referred to herein as carboxylic acid compounds.

  Examples of the trivalent or higher polyvalent carboxylic acid compound include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, pyromellitic acid and other aromatic carboxylic acids, and these Derivatives such as acid anhydrides and alkyl (C1-3) esters are exemplified.

  Other acids include rosin; rosin modified with fumaric acid, maleic acid, acrylic acid, and the like.

  In the present invention, the carboxylic acid component is a trivalent or higher polyvalent carboxylic acid compound, preferably a trimellitic acid compound, more preferably a trimaleic anhydride compound, from the viewpoint of increasing the molecular weight of the resin and improving the low-temperature fixability and storage stability of the toner. It is desirable to contain merit acid. The content of the trivalent or higher polyvalent carboxylic acid compound is preferably 0.1 to 30 mol%, more preferably 1 to 25 mol%, and even more preferably 5 to 25 mol% in the carboxylic acid component of the condensation polymerization resin.

  The alcohol component may contain a monovalent alcohol and the carboxylic acid component may contain a monovalent carboxylic acid compound as appropriate from the viewpoint of adjusting the molecular weight of the resin and improving the offset resistance of the toner.

  The polycondensation reaction between the alcohol component and the carboxylic acid component can be performed in an inert gas atmosphere in the presence of an esterification catalyst such as a tin compound and a titanium compound, a polymerization inhibitor, and the like. ~ 250 ° C is preferred.

  As the tin compound, for example, dibutyltin oxide is known. However, in the present invention, tin (II) having no Sn—C bond is used from the viewpoint of good dispersibility in the condensation polymerization resin. Compounds are preferred.

  Examples of the tin (II) compound having no Sn—C bond include a tin (II) compound having a Sn—O bond, a tin (II) compound having a Sn—X (X represents a halogen atom) bond, and the like. Preferably, a tin (II) compound having a Sn—O bond is more preferable.

Examples of tin (II) compounds having Sn-O bonds include tin (II) oxalate, tin (II) acetate, tin (II) octoate, tin (II) 2-ethylhexanoate, and tin (II) laurate. , Tin (II) carboxylate having a carboxylic acid group having 2 to 28 carbon atoms, such as tin (II) stearate, tin (II) oleate; octyloxy tin (II), lauroxy tin (II), stearoxy tin (II) ), Alkoxytin (II) having an alkoxy group having 2 to 28 carbon atoms such as oleyloxytin (II); tin (II) oxide; tin (II) sulfate, Sn—X (X represents a halogen atom) Examples of the tin (II) compound having a bond include tin (II) halides such as tin (II) chloride and tin (II) bromide. Among these, from the viewpoint of catalytic ability, (R ¹ COO) ₂ Sn (wherein R ¹ represents an alkyl group or alkenyl group having 5 to 19 carbon atoms), fatty acid tin (II), (R ² O) ₂ Sn (where R ² is carbon number 6) ~ 20 alkyl or alkenyl groups Alkoxy tin (II) and tin oxide represented by SnO (II) is preferably represented by the be), (R ¹ COO) is more preferably a fatty acid tin represented by ₂ Sn (II) and tin oxide (II) Further preferred are tin (II) octoate, tin (II) 2-ethylhexanoate, tin (II) stearate and tin (II) oxide.

  As the titanium compound, a titanium compound having a Ti-O bond is preferable, and a compound having an alkoxy group having 1 to 28 carbon atoms, an alkenyloxy group having 2 to 28 carbon atoms, or an acyloxy group having 1 to 28 carbon atoms in total is preferable. More preferred.

Specific examples of titanium compounds include titanium diisopropylate bistriethanolamate [Ti (C ₆ H ₁₄ O ₃ N) ₂ (C ₃ H ₇ O) ₂ ], titanium diisopropylate bisdiethanolamate [Ti (C ₄ H ₁₀ O ₂ N) ₂ (C ₃ H ₇ O) ₂ ], titanium dipentylate bistriethanolamate [Ti (C ₆ H ₁₄ O ₃ N) ₂ (C ₅ H ₁₁ O) ₂ ], titanium diety rate bis triethanolaminate _{[Ti (C 6 H 14 O 3} N) 2 (C 2 H 5 O) 2 ], titanium dihydroxy octylate bis triethanolaminate _{[Ti (C 6 H 14 O 3} N) 2 (OHC 8 H ₁₆ O) ₂ ], titanium distearate bistriethanolamate [Ti (C ₆ H ₁₄ O ₃ N) ₂ (C ₁₈ H ₃₇ O) ₂ ], titanium triisopropylate triethanolamate [Ti (C ₆ H ₁₄ O ₃ N) (C ₃ H ₇ O) ₃ ], titanium monopropylate tris (triethanolaminate) [Ti (C ₆ H ₁₄ O ₃ N) ₃ (C ₃ H ₇ O)] and the like, among these, titanium diisopropylate bistri Ethanolaminate, titanium diisopropylate bisdiethanolamate and titanium dipentylate bistriethanolamate are preferred, and these are also available as commercial products of Matsumoto Trading Co., Ltd., for example.

Specific examples of other preferable titanium compounds include tetra-n-butyl titanate [Ti (C ₄ H ₉ O) ₄ ], tetrapropyl titanate [Ti (C ₃ H ₇ O) ₄ ], tetrastearyl titanate [Ti ( C ₁₈ H ₃₇ O) ₄ ], tetramyristyl titanate [Ti (C ₁₄ H ₂₉ O) ₄ ], tetraoctyl titanate [Ti (C ₈ H ₁₇ O) ₄ ], dioctyl dihydroxyoctyl titanate [Ti (C ₈ H ₁₇ O) ₂ (OHC ₈ H ₁₆ O) ₂ ], dimyristyl dioctyl titanate [Ti (C ₁₄ H ₂₉ O) ₂ (C ₈ H ₁₇ O) ₂ ] and the like. Among these, tetrastearyl titanate, tetra Myristyl titanate, tetraoctyl titanate and dioctyl dihydroxy octyl titanate are preferred. These can be obtained, for example, by reacting a titanium halide with a corresponding alcohol, or can be obtained as a commercial product such as Nisso.

  The said tin (II) compound and titanium compound can be used 1 type or in combination of 2 or more types.

  The amount of the esterification catalyst is preferably 0.01 to 2.0 parts by weight, more preferably 0.1 to 1.5 parts by weight, and still more preferably 0.2 to 1.0 parts by weight with respect to 100 parts by weight of the total amount of the alcohol component and the carboxylic acid component.

  Examples of the condensation polymerization resin include polyester and polyamide from the viewpoint of low-temperature fixability of the toner, and polyester is preferable from the viewpoint of durability and charge stability of the toner.

  Examples of the raw material monomer for forming the amide component include various known polyamines, aminocarboxylic acids, amino alcohols and the like.

  In addition, polyester modified | denatured to such an extent that the characteristic is not impaired substantially may be sufficient. Examples of the modified polyester include grafting and blocking with phenol, urethane, epoxy and the like by the methods described in JP-A-11-133668, JP-A-10-239903, JP-A-8-20636, and the like. Polyester.

  On the other hand, the styrene resin is a resin obtained by addition polymerization of a raw material monomer containing a styrene derivative such as styrene, α-methylstyrene, vinyltoluene and the like.

  The content of the styrene derivative is preferably 50% by weight or more, more preferably 70% by weight or more, and further preferably 80% by weight or more in the raw material monomer of the styrene resin.

  Examples of raw material monomers for styrene resins that can be used in addition to styrene derivatives include (meth) acrylic acid alkyl esters; ethylenically unsaturated monoolefins such as ethylene and propylene; diolefins such as butadiene; and halovinyls such as vinyl chloride. Vinyl esters such as vinyl acetate and vinyl propionate; esters of ethylenic monocarboxylic acids such as dimethylaminoethyl (meth) acrylate; vinyl ethers such as vinyl methyl ether; vinylidene halides such as vinylidene chloride; N-vinyl And N-vinyl compounds such as pyrrolidone. In the present specification, “(meth) acrylic acid” means acrylic acid and / or methacrylic acid.

  Of these, (meth) acrylic acid alkyl esters are preferred from the viewpoint of low-temperature fixability and charge stability. From the above viewpoint, the number of carbon atoms of the alkyl group in the (meth) acrylic acid alkyl ester is preferably 1 to 22, and more preferably 8 to 18. In addition, carbon number of this alkyl ester says carbon number derived from the alcohol component which comprises ester. Specifically, methyl (meth) acrylate, ethyl (meth) acrylate, (iso) propyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (iso or tertiary) butyl (meth) acrylate, 2-ethylhexyl (Meth) acrylate, (iso) octyl (meth) acrylate, (iso) decyl (meth) acrylate, (iso) stearyl (meth) acrylate, and the like. "(Iso or tertiary)", "(iso)" means including both present and absent groups, and when these groups are not present, Indicates normal. Further, “(meth) acrylate” indicates that both acrylate and methacrylate are included.

  The content of the (meth) acrylic acid alkyl ester is preferably 50% by weight or less, more preferably 30% by weight or less in the raw material monomer of the styrene resin from the viewpoint of low-temperature fixability, storage stability and charge stability of the toner. 20% by weight or less is more preferable.

  A resin obtained by addition polymerization of a raw material monomer containing a styrene derivative and a (meth) acrylic acid alkyl ester is also referred to as a styrene- (meth) acrylic resin.

  The addition polymerization reaction of the raw material monomer of the styrenic resin can be performed by a conventional method 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. 200 degreeC is preferable and 140-170 degreeC is more preferable.

  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 styrene resin raw material monomer.

  The composite resin in the present invention may contain a condensation polymerization resin and a styrene resin from the viewpoint of storage stability, hot offset resistance, and durability of the toner. However, a resin obtained by polymerizing a raw material monomer of a condensation polymerization resin and a raw material monomer of a styrene resin is preferable. Such a composite resin can be obtained, for example, by performing a condensation polymerization reaction with a raw material monomer of a condensation polymerization resin and an addition polymerization reaction with a raw material monomer of a styrene resin in parallel or sequentially in the same reaction vessel. . The progress and completion of the polycondensation reaction and the addition polymerization reaction do not need to be simultaneous in time. The reaction temperature and time may be appropriately selected according to each reaction mechanism, and the reaction may proceed and complete. The condensation polymerization reaction and the addition polymerization reaction are preferably performed in the same reaction vessel.

  In the present invention, from the viewpoint of improving the storage stability, hot offset resistance, and durability of the toner, the composite resin is used in addition to the raw material monomer of the polycondensation resin and the raw material monomer of the styrene resin. A hybrid resin obtained using a compound capable of reacting (both reactive monomers) is preferred. Therefore, when the raw material monomer of the condensation polymerization resin and the raw material monomer of the styrene resin are polymerized to obtain the composite resin, the condensation polymerization reaction and the addition polymerization reaction are preferably performed in the presence of both reactive monomers. As a result, the composite resin becomes a hybrid resin in which the condensation polymerization resin and the styrene resin are partially bonded via the both reactive monomers, and the condensation polymerization resin component has a finer styrene resin component, and It will be uniformly dispersed.

  As the both reactive monomers, in the molecule, 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, preferably a hydroxyl group and / or A compound having a carboxyl group, more preferably a carboxyl group, and an ethylenically unsaturated bond is preferred. By using such a bireactive monomer, the dispersibility of the resin that becomes the dispersed phase can be further improved. . Both reactive monomers are preferably at least one selected from the group consisting of acrylic acid, methacrylic acid, fumaric acid, maleic acid and maleic anhydride, but from the viewpoint of reactivity, acrylic acid, methacrylic acid and Fumaric acid is more preferred.

  The content of both reactive monomers is preferably 1 to 20 mol% and more preferably 2 to 15 mol% in the total amount of the alcohol component and the carboxylic acid component of the condensation polymerization resin. Here, the both reactive monomers are handled as raw material monomers for the condensation polymerization resin. In the present invention, when calculating the content of the bireactive monomer and the content of the alcohol A relative to the total amount of the alcohol component and the carboxylic acid component other than the alcohol A, the amount of the bireactive monomer is determined by the condensation polymerization resin. The raw material monomer is included in the total amount of the alcohol component and the carboxylic acid component.

As a specific manufacturing method of the composite resin,
(i) a method of performing a step (B) of performing an addition polymerization reaction after the step (A) of performing the condensation polymerization reaction;
(ii) After the step (A) for carrying out the condensation polymerization reaction, the step (B) for carrying out the addition polymerization reaction is carried out, and after the step (B), the reaction temperature is raised again to become a crosslinking agent if necessary. A method in which a raw material monomer of a polycondensation resin having a value equal to or higher than that is added to the polymerization system, and the condensation polymerization reaction in step (A) is further advanced
(iii) The step (A) for performing the condensation polymerization reaction and the step (B) for performing the addition polymerization reaction are performed in parallel under a temperature condition suitable for the addition polymerization reaction, and the reaction temperature is maintained under the above-described conditions. After completing the step (B), the reaction temperature is raised, and if necessary, a raw material monomer of a trivalent or higher polycondensation resin as a crosslinking agent is added to the polymerization system, and the polycondensation reaction of the step (A) And a method of further proceeding. In the methods (i) and (ii), a prepolymerized polycondensation resin may be used instead of the step (A) in which the polycondensation reaction is performed. In the method (iii), when the step (A) and the step (B) are performed in parallel, a mixture containing the raw material monomer of the condensation polymerization resin is mixed with the mixture containing the raw material monomer of the condensation polymerization resin. It can also be made to react by dripping.

  Moreover, when the composite resin is a hybrid resin obtained using an amphoteric monomer, the amphoteric monomer is preferably used together with a raw material monomer for a styrene resin.

  In the present invention, the composite resin may be a resin obtained by polymerizing raw material monomers in the presence of wax.

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

  The softening point of the composite resin is preferably from 90 to 160 ° C, more preferably from 95 to 155 ° C, and even more preferably from 115 to 150 ° C, from the viewpoint of low-temperature fixability, storage stability and durability of the toner. The glass transition point is preferably 45 to 85 ° C., more preferably 50 to 80 ° C., and still more preferably 58 to 75 ° C. from the viewpoint of low-temperature fixability, storage stability and durability of the toner. From the viewpoint of the chargeability and environmental stability of the toner, the acid value is preferably from 1 to 90 mgKOH / g, more preferably from 5 to 90 mgKOH / g, and even more preferably from 5 to 88 mgKOH / g.

  By the method including the step of granulating the raw material containing the composite resin as a binder resin in an aqueous medium, it is excellent in both low temperature fixability and storability, which are mutually contradictory performances, and also has hot offset resistance and durability. An electrophotographic toner excellent in the above can be obtained.

  In the toner of the present invention, a known binder resin other than the composite resin, for example, a vinyl resin such as polyester and styrene-acrylic resin, an epoxy resin, a polycarbonate, a polyurethane, and the like, as long as the effects of the present invention are not impaired. A resin may be used in combination, but the content of the composite resin is preferably 30% by weight or more, more preferably 50% by weight or more, still more preferably 70% by weight or more, and 80% by weight in the total binder resin. The above is more preferable, 90% by weight or more is more preferable, and substantially 100% by weight is further preferable.

  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, all of dyes and pigments used as toner colorants can be used. Carbon black, black pigment, 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, Isoindoline, Disazo yellow and the like can be used alone or in combination of two or more. The toner may be either black toner or color toner.

  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 charge control agent include chromium-based azo dyes, iron-based azo dyes, aluminum azo dyes, salicylic acid metal complexes, and the like, and these can be used alone or in admixture of two or more.

  The content of the charge control agent is preferably 0.1 to 8 parts by weight and more preferably 0.5 to 7 parts by weight with respect to 100 parts by weight of the binder resin.

  Release agents include polyolefin wax, paraffin wax, silicones; fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide, stearic acid amide; carnauba wax, rice wax, candelilla wax, wood wax, jojoba Plant waxes such as oils; animal waxes such as beeswax; waxes such as mineral and petroleum waxes such as montan wax, ozokerite, ceresin, microcrystalline wax, and Fischer-Tropsch wax, which are used alone or in combination of two or more Can be mixed and used.

  The melting point of the release agent is preferably 60 to 160 ° C., more preferably 60 to 150 ° C., from the viewpoints of low-temperature fixability and offset resistance of the toner.

  The content of the release agent is preferably 0.5 to 10 parts by weight, more preferably 1 to 8 parts by weight, and more preferably 1 to 7 parts by weight with respect to 100 parts by weight of the binder resin, from the viewpoint of dispersibility in the binder resin. Part by weight is more preferred.

  The electrophotographic toner of the present invention is not particularly limited as long as it can be obtained by a method including a step of forming a raw material containing the binder resin according to the present invention in an aqueous medium, and for example, (A) A method in which the primary particles of the binder resin are formed in advance in an aqueous medium, and then the primary particles are aggregated and coalesced. (B) After the primary particles of the binder resin are formed in advance in the aqueous medium, Examples thereof include a method of fusing primary particles, and a method (C) of dispersing a raw material containing a binder resin in an aqueous medium to form particles.

  In the present invention, the method (A) is preferable, and after introducing an aqueous medium into a mixed solution prepared by dissolving or dispersing a raw material containing a binder resin in an organic solvent, the organic solvent is removed, and the binding is performed. A method comprising a step (1) of obtaining an aqueous dispersion of primary particles containing a resin and a step (2) of aggregating and coalescing the primary particles is preferable. As another specific example of the method (A), a step (1 ′) of producing primary particles containing a binder resin in an aqueous medium in the presence of a nonionic surfactant, and the primary particles There is a method including a step (2) of aggregating and coalescing them. As a specific example of the method (B), a radical polymerizable monomer solution in which a binder resin is dissolved is emulsion-polymerized to obtain resin fine particles, and the resin fine particles are fused in an aqueous medium (Japanese Patent Laid-Open No. 2001-2001). As a specific example of the method (C), the raw material containing the binder resin is heated and melted and dispersed in an aqueous medium containing no organic solvent while maintaining the molten state of the binder resin. Then, a method of drying (see JP 2001-235904 A) and the like are included.

  In step (1), an aqueous medium is introduced into a mixed solution prepared by dissolving or dispersing a raw material containing a binder resin in an organic solvent, and then the organic solvent is removed and the primary containing the binder resin. This is a step of obtaining an aqueous dispersion of particles.

  The amount of the organic solvent used is preferably 100 to 1000 parts by weight with respect to 100 parts by weight of the binder resin. Water and, if necessary, a neutralizing agent are mixed in the mixed solution and stirred, and then the organic solvent is removed from the obtained dispersion to obtain a primary particle aqueous dispersion of self-dispersing resin.

  The amount of the aqueous medium used is preferably 100 to 1000 parts by weight with respect to 100 parts by weight of the organic solvent. The aqueous medium used in the method (1) and the step (1 ′) described later may contain a solvent such as an organic solvent, but water is preferably 50% by weight or more, preferably 70% by weight or more. More preferably, it is 90% by weight or more, more preferably 99% by weight or more.

  When stirring the mixture, a commonly used mixing and stirring device such as an anchor blade can be used. Examples of the neutralizing agent include alkali metals such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; organic bases such as ammonia, trimethylamine, ethylamine, diethylamine, triethylamine, triethanolamine, and tributylamine.

  Further, the dispersion of primary particles containing the binder resin can be made into a dispersion without using an organic solvent as in the step (1 ').

  Step (1 ') is a step of producing primary particles containing a binder resin in an aqueous medium in the presence of a nonionic surfactant.

  According to the method of the step (1 '), the binder resin can be atomized by using only water without substantially using an organic solvent.

  In step (1 '), a binder resin containing a composite resin and a nonionic surfactant can be mixed to form a dispersion without using an organic solvent. This can reduce the viscosity of the mixture and atomize the binder resin, but this is because the nonionic surfactant is compatible with the binder resin and the viscosity of the mixture decreases. This is because the point is apparently lowered. By utilizing this phenomenon, the apparent softening point of the binder resin compatible with the nonionic surfactant can be lowered below the boiling point of water, and the resin alone has a melting point or softening point of 100 ° C. or higher. Even with the binder resin, a dispersion liquid in which the binder resin is dispersed in water can be obtained by dropping water at normal pressure. This method requires at least water and a nonionic surfactant, so it can be applied to resins that are insoluble in organic solvents, and does not require the burden of equipment for recovering organic solvents and maintaining the work environment. There is also an advantage that a resin dispersion can be produced economically because a special device required when using mechanical means is not required.

  Examples of the nonionic surfactant used in the step (1 ′) include polyoxyethylene alkyl allyl ethers such as polyoxyethylene nonylphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, and polyoxyethylene alkyl. Polyethers such as ethers, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan esters such as polyoxyethylene sorbitan monostearate, polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene glycol monooleate Examples thereof include oxyethylene fatty acid esters and oxyethylene / oxypropylene block copolymers. In addition, an anionic surfactant or a cationic surfactant may be used in combination with the nonionic surfactant.

  As the nonionic surfactant, it is preferable to select a nonionic surfactant having good compatibility with the binder resin. In order to obtain a stable binder resin dispersion, the HLB of the nonionic surfactant is preferably 12 to 20, and depending on the type of the binder resin, two or more different HLB nonionic interfaces may be used. More preferably, an activator is used. For example, in the case of a highly hydrophilic resin, at least one nonionic surfactant having an HLB of 12 to 18 may be used. In the case of a highly hydrophobic resin, a low HLB, for example, an HLB of 7 It is preferable to adjust the weighted average of both HLBs to 12 to 20 by using about 10 or so and those having a high HLB, for example, 14 to 20 HLB. In this case, it is presumed that mainly those having an HLB of about 7 to 10 can compatibilize the resin, and those having a high HLB can stabilize the dispersion of the resin in water.

  Moreover, when using a coloring agent, it is preferable to make a nonionic surfactant adsorb | suck to a coloring agent. By adjusting the HLB of the nonionic surfactant to the above range, the nonionic surfactant can be easily adsorbed on the colorant surface, and can be stably present in the binder resin.

  The clouding point of the nonionic surfactant is preferably 70 to 105 ° C., more preferably 80 to 105 ° C. when the binder resin is atomized under normal pressure and water.

  From the viewpoint of lowering the melting point of the binder resin, the amount of the nonionic surfactant used is preferably 5 parts by weight or more with respect to 100 parts by weight of the binder resin, and controls the nonionic surfactant remaining in the toner. From this viewpoint, the amount is preferably 80 parts by weight or less. Therefore, from the viewpoint of making these compatible, the amount of the nonionic surfactant used is preferably 5 to 80 parts by weight, more preferably 10 to 70 parts by weight, and more preferably 20 to 60 parts by weight with respect to 100 parts by weight of the binder resin. Part by weight is more preferred.

  In the step (1 ′), when the primary particles containing the binder resin are produced in the aqueous medium in the presence of the nonionic surfactant, the temperature in the system depends on the dispersibility of the nonionic surfactant. From the viewpoint of preventing the dispersion efficiency from decreasing, it is desirable to keep the nonionic surfactant within the temperature range of 10 ° C., preferably 8 ° C., more preferably 5 ° C. above and below the cloud point.

    In the step (1 ′), for example, an aqueous medium (preferably deionized water or distilled water) is added in a state where the mixture of the binder resin and the nonionic surfactant is stirred and uniformly mixed in the system. It is preferable to dripping. In the case of using a colorant, it is preferable that the binder resin containing the colorant compatible with the nonionic surfactant is not separated from water.

  The amount of the aqueous medium used in the step (1 ′) is preferably 100 to 3000 parts by weight, more preferably 400 to 3000 parts by weight with respect to 100 parts by weight of the binder resin, from the viewpoint of obtaining uniform aggregated particles in the subsequent step. 800 to 3000 parts by weight are more preferable.

  The particle size of the primary particles containing the binder resin including the composite resin can be controlled by the amount of the nonionic surfactant, the degree of stirring, the addition rate of water, and the like. In step (1), the rate at which the aqueous medium is added to the mixture containing at least the binder resin and the nonionic surfactant is preferably 0.1 to 50 g / min per 100 g of the mixture from the viewpoint of obtaining uniform primary particles. 0.5-40 g / min is more preferable, and 1-30 g / min is more preferable.

  In addition, when the binder resin has an acidic group such as a carboxyl group or a sulfone group, water may be added after neutralizing all or part of the binder resin or while neutralizing the binder resin. When using what has an acidic group for binder resin, in addition to the factor of a nonionic surfactant, the self-emulsifying property of resin becomes a control factor of the particle size of a primary particle.

  A dispersant can be used for the purpose of lowering the melt viscosity and melting point of the binder resin and improving the dispersibility of the primary particles produced. Examples of the dispersant include water-soluble polymers such as polyvinyl alcohol, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium polyacrylate, and sodium polymethacrylate; sodium dodecylbenzenesulfonate, sodium octadecylsulfate, sodium oleate, Anionic surfactants such as sodium laurate and potassium stearate; Cationic surfactants such as laurylamine acetate, stearylamine acetate and lauryltrimethylammonium chloride; Amphoteric surfactants such as lauryldimethylamine oxide; Tricalcium phosphate, Water Examples thereof include inorganic salts such as aluminum oxide, calcium sulfate, calcium carbonate, and barium carbonate. The amount of the dispersant used is preferably 20 parts by weight or less, more preferably 15 parts by weight or less, and even more preferably 10 parts by weight or less with respect to 100 parts by weight of the binder resin from the viewpoint of emulsion stability and detergency.

  The solid content concentration of the primary particles containing the binder resin obtained in step (1) or step (1 ′) (hereinafter also simply referred to as primary particles) is determined by the stability of the dispersion and the aggregation step. From the viewpoint of the handleability of the dispersion, it is preferably 7 to 50% by weight, more preferably 7 to 40% by weight. The solid content includes non-volatile components such as a resin and a nonionic surfactant.

The average primary particle diameter is preferably 0.05 to 3 μm, more preferably 0.05 to 1 μm, and even more preferably 0.05 to 0.8 μm from the viewpoint of uniformly agglomerating in the subsequent step. In the present invention, the average particle size of primary particles refers to the volume median particle size (D ₅₀ ), and can be measured by a laser diffraction type particle size measuring instrument or the like.

  Then, the process (process (2)) which aggregates and unites the primary particle obtained at the process (1) is demonstrated.

  In step (2), the solid content concentration in the system in the aggregation step of aggregating the primary particles obtained in step (1) or step (1 ′) is adjusted by adding water to the binder resin dispersion. In order to cause uniform aggregation, 5 to 50% by weight is preferable, 5 to 30% by weight is more preferable, and 5 to 20% by weight is further preferable.

  The pH in the system in the aggregation step is preferably 2 to 10, more preferably 2 to 9, more preferably 3 to 8, from the viewpoint of achieving both the dispersion stability of the mixed solution and the aggregation properties of fine particles such as a binder resin. Further preferred.

  From the same viewpoint, the temperature in the system in the aggregation process is preferably a softening point of the binder resin of −70 ° C. or more and a softening point or less.

  In addition, additives such as a colorant and a charge control agent may be premixed in the binder resin when preparing the primary particles, or a dispersion liquid in which each additive is separately dispersed in a dispersion medium such as water. It may be prepared, mixed with primary particles, and subjected to an aggregation process. When the additive is previously mixed with the binder resin when preparing the primary particles, it is preferable to melt and knead the binder resin and the additive in advance. For melt kneading, it is preferable to use an open roll type biaxial kneader. The open roll type twin-screw kneader is a kneader in which two rolls are arranged close to each other in parallel, and a heating function or a cooling function can be imparted by passing a heat medium through each roll. Therefore, the open roll type twin screw kneader is an open type part to be melt kneaded and is provided with a heating roll and a cooling roll. The heat of kneading generated can be easily dissipated.

  In the aggregation process, an aggregating agent can be added in order to effectively perform aggregation. As an aggregating agent, a quaternary salt cationic surfactant, polyethyleneimine, or the like is used in an organic system, and an inorganic metal salt, a divalent or higher metal complex, or the like is used in an inorganic system. Examples of inorganic metal salts include metal salts such as sodium sulfate, sodium chloride, calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, aluminum sulfate, polyaluminum chloride, polyaluminum hydroxide, Examples thereof include inorganic metal salt polymers such as calcium sulfide.

  The amount of the flocculant used is preferably 30 parts by weight or less, more preferably 20 parts by weight or less, and even more preferably 10 parts by weight or less with respect to 100 parts by weight of the binder resin from the viewpoint of environmental resistance characteristics of the toner.

  Subsequently, the agglomerated particles containing at least the binder resin obtained in the aggregating step are heated and united (a uniting step).

  The temperature in the system in the coalescence process is from the viewpoint of the target toner particle size, particle size distribution, shape control, and particle fusing property, the softening point of the binder resin is −50 ° C. or higher, and the softening point is + 10 ° C. or lower. The softening point is -45 ° C or higher and the softening point + 10 ° C or lower is more preferable, and the softening point is -40 ° C or higher and the softening point + 10 ° C or lower is more preferable. The stirring speed is preferably a speed at which the aggregated particles do not settle. In the present invention, when two or more kinds of resins are used as the binder resin, the softening point of the mixed resin is set as the softening point of the binder resin.

  A toner can be obtained by subjecting the coalesced particles obtained in the step (2) to a solid-liquid separation step such as filtration, a washing step, and a drying step as appropriate.

  In the washing step, it is preferable to use an acid in order to remove metal ions on the toner surface in order to ensure sufficient charging characteristics and reliability as the toner. Further, it is preferable to completely remove the added nonionic surfactant by washing, and washing with an aqueous solution below the cloud point of the nonionic surfactant is preferred. The washing is preferably performed a plurality of times.

  In the drying step, any method such as a vibration type fluidized drying method, a spray drying method, a freeze drying method, a flash jet method, or the like can be employed.

The volume median particle size (D ₅₀ ) of the toner of the present invention is preferably 1 to 10 μm, more preferably 2 to 8 μm, and further preferably 3 to 7 μm. 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.

  An external additive may be added to the surface of the toner. Examples of the external additive include inorganic fine particles such as silica, alumina, titanium oxide, zirconia, tin oxide, and zinc oxide, and organic fine particles such as resin fine particles. It may be given. The addition amount of the external additive is preferably 0.05 to 5 parts by weight with respect to 100 parts by weight of the toner particles before being processed with the external additive.

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

[Softening point of resin]
Using a flow tester (Shimadzu Corporation, CFT-500D), a 1 g sample is heated at a heating rate of 6 ° C / min, and a 1.96 MPa load is 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), weigh 0.01 to 0.02 g of the sample into an aluminum pan, raise the temperature to 200 ° C, and from that temperature to 0 ° C at a rate of 10 ° C / min. The temperature of the cooled sample is raised at a heating rate of 10 ° C / min, and the temperature at the intersection of the base line extension below the maximum peak temperature of endotherm and the tangent that indicates the maximum slope from the peak rise to the peak apex To do.

[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)).

[Average particle size of particles in dispersion]
Using a laser diffraction particle size analyzer (manufactured by Shimadzu Corporation, SALD-2000J), add distilled water to the measurement cell and measure the volume median particle size (D ₅₀ ) at a concentration where the absorbance is in the proper range. To do.

[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 diameter of toner (D ₅₀ )]
Measuring machine: Coulter Multisizer II (Beckman Coulter, Inc.)
Aperture diameter: 50μm
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) 5% electrolyte dispersion condition: 10 mg of measurement sample is added to 5 ml of dispersion, and dispersed for 1 minute with an ultrasonic disperser. Then, 25 ml of the electrolytic solution is added, and further dispersed with an ultrasonic disperser for 1 minute.
Measurement conditions: Add 100 ml of electrolyte and dispersion in a beaker, measure 30,000 particles at a concentration that can measure the particle size of 30,000 particles in 20 seconds, and determine the volume-median particle size ( determine the D _50).

Resin Production Example 1 [Resin A, B, D, F, G, I, J]
Put the raw material monomer of the polyester other than trimellitic anhydride shown in Tables 1 and 2 and the esterification catalyst into a 5-liter four-necked flask equipped with a thermometer, a stainless steel stirring rod, a flow-down condenser and a nitrogen inlet tube, After heating up to 180 ° C. in a mantle heater in a nitrogen atmosphere, the temperature was raised to 230 ° C. over 10 hours. Thereafter, it was confirmed that the reaction rate reached 95% or higher at 230 ° C., cooled to 160 ° C., and a mixed solution of styrene resin raw material monomers, both reactive monomers and a polymerization initiator shown in Tables 1 and 2. Was added dropwise over 1 hour. Then, after maintaining at 160 ° C. for 30 minutes, the temperature was raised to 210 ° C., and the reaction was performed at 8 kPa for 1 hour. Thereafter, trimellitic anhydride shown in Tables 1 and 2 was added, and a reaction was performed at 40 kPa until a desired softening point was reached, thereby obtaining a hybrid resin. The reaction rate means a value of the amount of produced reaction water / theoretical product water amount × 100.

Resin Production Example 2 [Resin C]
Polyester raw materials other than trimellitic anhydride shown in Table 1 are placed in a 5-liter four-necked flask equipped with a thermometer, a stainless steel stirring rod, a flow-down condenser and a nitrogen inlet tube, and a mantle heater in a nitrogen atmosphere The mixture was cooled to 160 ° C., and a mixed solution of styrene resin raw material monomer, amphoteric monomer and polymerization initiator shown in Table 1 was added dropwise over 1 hour. Then, after maintaining at 160 ° C. for 30 minutes, an esterification catalyst was added, the temperature was raised to 180 ° C., and then the temperature was raised to 230 ° C. over 10 hours. After confirming that the reaction rate reached 95% or higher at 230 ° C, the temperature was raised to 210 ° C, and then trimellitic anhydride shown in Table 1 was added until the desired softening point was reached at 40 kPa. Reaction was performed to obtain a hybrid resin.

Resin Production Example 3 [Resin E]
Put polyester raw material monomer and esterification catalyst other than trimellitic anhydride shown in Table 1 into a 5 liter four-necked flask equipped with a thermometer, a stainless steel stir bar, a flow-down condenser and a nitrogen inlet tube, and a nitrogen atmosphere. In the mantle heater, the temperature was raised to 180 ° C and then raised to 230 ° C over 10 hours. After confirming that the reaction rate reached 95% or higher at 230 ° C, cooled to 160 ° C, charged with wax, styrene resin raw material monomers, both reactive monomers and polymerization initiator shown in Table 1 Was added dropwise over 1 hour. Then, after maintaining at 160 ° C. for 30 minutes, the temperature was raised to 210 ° C., and the reaction was performed at 8 kPa for 1 hour. Thereafter, trimellitic anhydride shown in Table 1 was added, and a reaction was performed at 40 kPa until a desired softening point was reached, thereby obtaining a hybrid resin.

Resin Production Example 4 [Resin H]
Polyester raw material monomers and esterification catalysts other than fumaric acid and trimellitic anhydride shown in Table 2 are placed in a 5-liter four-necked flask equipped with a thermometer, a stainless steel stirring rod, a flow-down condenser and a nitrogen inlet tube. After heating up to 180 ° C in a mantle heater in a nitrogen atmosphere, the temperature was raised to 230 ° C over 10 hours. After confirming that the reaction rate reached 95% or higher at 230 ° C, it was cooled to 160 ° C, and the mixed solution of styrene resin raw material monomer, both reactive monomers and polymerization initiator shown in Table 2 was added for 1 hour. It was dripped over. Then, after maintaining at 160 ° C. for 30 minutes, the trimellitic anhydride, fumaric acid and polymerization inhibitor shown in Table 2 were added, the temperature was raised to 210 ° C. over 4 hours, and then the desired softening point at 40 kPa. The reaction was carried out until a hybrid resin was obtained.

Resin Production Example 5 [Resin K]
Put polyester raw material monomer and esterification catalyst other than trimellitic anhydride shown in Table 3 into a 5 liter four-necked flask equipped with a thermometer, stainless steel stirring rod, flow-down condenser, and nitrogen inlet tube, and a nitrogen atmosphere The temperature was raised to 235 ° C in a mantle heater at 235 ° C, and the reaction was carried out at 235 ° C for 10 hours. Thereafter, the mixture was reacted at 235 ° C. and 8 kPa for 1 hour, then cooled to 210 ° C., and trimellitic anhydride shown in Table 3 was added. After reacting at normal pressure for 1 hour, the reaction was performed at 40 kPa until the desired softening point was reached, thereby obtaining a polyester.

Resin Production Example 6 [Resin L]
Put polyester raw material monomer and esterification catalyst other than trimellitic anhydride shown in Table 3 into a 5 liter four-necked flask equipped with a thermometer, stainless steel stirring rod, flow-down condenser, and nitrogen inlet tube, and a nitrogen atmosphere The temperature was raised to 180 ° C. in a mantle heater and then heated to 230 ° C. over 10 hours. Thereafter, it was confirmed that the reaction rate reached 95% or higher at 230 ° C, and after cooling to 210 ° C, trimellitic anhydride shown in Table 3 was added. After reacting at normal pressure for 1 hour, the reaction was performed at 40 kPa until the desired softening point was reached, thereby obtaining a polyester.

Examples 1-12 and Comparative Examples 1-3
(Preparation of resin dispersion)
600 g of methyl ethyl ketone was put into a 5 L container equipped with a stirrer, reflux condenser, dropping funnel, thermometer and nitrogen introducing tube, and 200 g of binder resin shown in Table 4 was added at room temperature to dissolve. The resulting solution was neutralized by adding 10 g of triethylamine, and then 2000 g of ion exchange water was added, and then methyl ethyl ketone was distilled off at a temperature of 50 ° C. or lower under reduced pressure at a stirring speed of 250 r / min. A self-dispersing aqueous resin particle dispersion (resin content: 9.6% by weight (in terms of solid content)) was obtained. The average particle diameter of the polyester particles (primary particles) dispersed in the obtained resin dispersion was 0.3 μm.

(Preparation of colorant dispersion)
Copper phthalocyanine (manufactured by Dainichi Seika Co., Ltd.) 50 g, nonionic surfactant (Emulgen 150, manufactured by Kao Corporation, polyoxyethylene lauryl ether, HLB: 18.4, cloud point: 100 ° C. or higher) 5 g and ion-exchanged water 200 g Were mixed, copper phthalocyanine was dissolved, and dispersed for 10 minutes using a homogenizer to obtain a dispersed colorant dispersion.

(Preparation of release agent dispersion)
Paraffin wax (HNP0190, manufactured by Nippon Seiwa Co., Ltd., melting point: 85 ° C) 50g, cationic surfactant (Sanisol B50, manufactured by Kao Corp.) 5g and ion-exchanged water 200g are heated to 95 ° C and homogenizer. Was used to disperse the paraffin wax, followed by dispersion with a pressure discharge type homogenizer to obtain a release agent dispersion in which the paraffin wax was dispersed with an average particle size of 550 nm.

(Preparation of charge control agent dispersion)
Charge control agent (Bontron E-84, manufactured by Orient Chemical Co., Ltd.) 50 g, nonionic surfactant (Emulgen 150, manufactured by Kao Corporation, polyoxyethylene lauryl ether, HLB: 18.4, cloud point: 100 ° C. or higher) 5 g and 200 g of ion-exchanged water were mixed, using glass beads, and dispersed for 10 minutes using a sand grinder to prepare a charge control agent dispersion in which the charge control agent was dispersed with an average particle size of 500 nm. Some coarse particles were observed.

[Aggregation process]
490 g of the obtained resin particle dispersion, 20 g of the colorant dispersion, 15 g of the release agent dispersion, 7 g of the charge control agent dispersion and 2 g of the cationic surfactant (Sanisol B50, manufactured by Kao Corporation) After mixing and dispersing in a stainless steel flask using a homogenizer, the flask was heated to 48 ° C. while stirring in the oil bath for heating. Furthermore, after maintaining at 48 ° C. for 1 hour, it was confirmed that aggregated particles having an average particle diameter of 6.0 μm were formed.

[Joint process]
After adding 3 g of an anionic surfactant (Perex SS-L, manufactured by Kao Corporation) to the aggregated particle dispersion in which aggregated particles are formed, a reflux tube is attached to the stainless steel flask and stirring is continued. While heating to 80 ° C. at a rate of 5 ° C./min and holding for 5 hours, the aggregated particles were coalesced and fused. Thereafter, the mixture was cooled, the fused particles were filtered, washed thoroughly with ion-exchanged water, and then dried, whereby the volume median particle size (D ₅₀ ) of the obtained colored resin fine particle powder was 6.3 μm.

[Surface treatment process]
1.0 part by weight of hydrophobic silica (TS530, manufactured by Wacker Chemie, number average particle size: 8 nm) is added to 100 parts by weight of the obtained colored resin fine particle powder, and the mixture is externally added using a Henschel mixer. Cyan toner was used. The resulting cyan toner had a volume median particle size (D ₅₀ ) of 6.5 μm.

Example 13
(Preparation of resin dispersion)
In a 5 liter stainless steel container, 1300 g of resin A, anionic surfactant (Neopelex G-15, manufactured by Kao Corporation, sodium dodecylbenzenesulfonate (solid content 15 wt%)) 100 g, nonionic surfactant ( Emulgen 430, manufactured by Kao Corporation, polyoxyethylene oleyl ether (EO = 26 mol addition), HLB: 16.2, cloud point: 100 ° C or higher) 100g, and 589% by weight potassium hydroxide aqueous solution 689g with a chi-type stirrer Disperse at 25 ° C. with stirring for min. The contents were stabilized at 95 ° C., and held for 2 hours with stirring at 200 r / min with a Kai-type stirrer. Subsequently, deionized water was added dropwise at 15 g / min with stirring at 200 r / min with a Kai-type stirrer, and a total of 2845 g was added. During this time, the temperature of the system was maintained at 95 ° C., and after cooling, a resin dispersion containing finely divided resin was obtained through a 150 mesh (mesh: 105 μm) wire mesh. The average particle size of the resin particles (primary particles) in the obtained resin dispersion was 0.15 μm, the solid concentration was 31% by weight, and no resin component remained on the wire mesh.

(Preparation of colorant dispersion)
Copper phthalocyanine (manufactured by Dainichi Seika Co., Ltd.) 50 g, nonionic surfactant (Emulgen 150, manufactured by Kao Corporation, polyoxyethylene lauryl ether, HLB: 18.4, cloud point: 100 ° C. or higher) 5 g and ion-exchanged water 200 g Were mixed, copper phthalocyanine was dissolved, and dispersed for 10 minutes using a homogenizer to obtain a dispersed colorant dispersion.

(Preparation of release agent dispersion)
Paraffin wax (HNP0190, manufactured by Nippon Seiwa Co., Ltd., melting point: 85 ° C) 50g, cationic surfactant (Sanisol B50, manufactured by Kao Corp.) 5g and ion-exchanged water 200g are heated to 95 ° C and homogenizer. Was used to disperse the paraffin wax, followed by dispersion with a pressure discharge type homogenizer to obtain a release agent dispersion in which the paraffin wax was dispersed with an average particle size of 550 nm.

(Preparation of charge control agent dispersion)
Charge control agent (Bontron E-84, manufactured by Orient Chemical Co., Ltd.) 50 g, nonionic surfactant (Emulgen 150, manufactured by Kao Corporation, polyoxyethylene lauryl ether, HLB: 18.4, cloud point: 100 ° C. or higher) 5 g and 200 g of ion-exchanged water were mixed, using glass beads, and dispersed for 10 minutes using a sand grinder to prepare a charge control agent dispersion in which the charge control agent was dispersed with an average particle size of 500 nm. Some coarse particles were observed.

[Aggregation process]
490 g of the obtained resin particle dispersion, 20 g of the colorant dispersion, 15 g of the release agent dispersion, 7 g of the charge control agent dispersion and 2 g of the cationic surfactant (Sanisol B50, manufactured by Kao Corporation) After mixing and dispersing in a stainless steel flask using a homogenizer (pH = 7), the flask was heated to 48 ° C. with stirring in an oil bath for heating. Furthermore, after maintaining at 48 ° C. for 1 hour, it was confirmed that aggregated particles having an average particle diameter of 6.0 μm were formed.

[Joint process]
After adding 3 g of an anionic surfactant (Perex SS-L, manufactured by Kao Corporation) to the aggregated particle dispersion in which aggregated particles are formed, a reflux tube is attached to the stainless steel flask and stirring is continued. While heating to 80 ° C. at a rate of 5 ° C./min and holding for 5 hours, the aggregated particles were coalesced and fused. Thereafter, the mixture was cooled, the fused particles were filtered, washed thoroughly with ion-exchanged water, and then dried, whereby the volume median particle size (D ₅₀ ) of the obtained colored resin fine particle powder was 6.3 μm.

[Surface treatment process]
1.0 part by weight of hydrophobic silica (TS530, manufactured by Wacker Chemie, number average particle size: 8 nm) is added to 100 parts by weight of the obtained colored resin fine particle powder, and the mixture is externally added using a Henschel mixer. Cyan toner was used. The resulting cyan toner had a volume-median particle size (D ₅₀ ) of 6.9 μm.

Test Example 1 [Hydrolysis resistance]
1.0 g of the binder resin used in each example and comparative example shown in Table 4 is placed in a 100 ml eggplant flask, 20 ml of a 0.1 mol / L potassium hydroxide methanol solution is added thereto, and further 20 ml of distilled water is added. Was added in a 90 ° C. water bath for 5 hours. After heating for 5 hours, the solution was neutralized with 0.1 mol / L hydrochloric acid, the solvent was removed, and the remaining resin was dried. The glass transition point (Tg) of the obtained resin was measured, Tg before and after the test was compared, and hydrolysis resistance was evaluated according to the following evaluation criteria. The results are shown in Table 4.

〔Evaluation criteria〕
A: Tg temperature difference between before and after the test is less than 1 ° C B: Tg temperature difference between before and after the test is between 1 ° C and less than 3 ° C C: Tg temperature difference between before and after the test is between 3 ° C and less than 6 ° C D: Temperature difference of Tg before and after the test is 6 ℃ or more

Test Example 2 [low temperature fixability]
Toner was mounted in an apparatus in which the fixing machine of the copier “AR-505” (manufactured by Sharp Corporation) was modified so that fixing was possible outside the apparatus, and an unfixed image was obtained. Using a fixing machine (fixing speed 390mm / sec) adjusted so that the total fixing pressure is 40kgf, the temperature of the fixing roll is gradually increased from 100 ° C to 240 ° C by 10 ° C. A fixing test was conducted. “UNICEF Cellophane” (Mitsubishi Pencil Co., Ltd., width: 18 mm, JISZ-1522) was attached to the fixed image, passed through a fixing roll set at 30 ° C., and then the tape was peeled off. The optical reflection density before and after the tape was peeled off was measured using a reflection densitometer “RD-915” (manufactured by Macbeth), and the ratio between the two (after peeling / before sticking × 100) was initially 90%. The fixing roll temperature exceeding the minimum fixing temperature was used, and the low-temperature fixing property was evaluated according to the following evaluation criteria. The results are shown in Table 4. The paper used in the fixing test was CopyBond SF-70NA (75 g / m ² ) manufactured by Sharp Corporation.

〔Evaluation criteria〕
A: The minimum fixing temperature is less than 140 ° C.
B: The minimum fixing temperature is 140 ° C. or higher and lower than 160 ° C.
C: The minimum fixing temperature is 160 ° C. or higher.

Test Example 3 [Hot offset resistance]
In Test Example 2, when the temperature of the fixing roll is sequentially increased from 90 ° C. to 240 ° C., the temperature at which offset is first confirmed is visually determined, and the hot offset resistance is evaluated according to the following evaluation criteria. did. The results are shown in Table 4.

〔Evaluation criteria〕
A: Hot offset generation temperature is 220 ° C or higher B: Hot offset generation temperature is 200 ° C or higher and lower than 220 ° C C: Hot offset generation temperature is 180 ° C or higher and lower than 200 ° C D: Hot offset generation temperature is lower than 180 ° C

Test Example 4 [Preservability]
4 g of toner was placed in a 20 ml container (diameter: about 3 cm) and left for 72 hours in an environment of 55 ° C. and 60% humidity. After standing, the degree of occurrence of toner aggregation was visually observed, and storage stability was evaluated according to the following evaluation criteria. The results are shown in Table 4.

〔Evaluation criteria〕
A: Aggregation is not observed at all after 48 hours and 72 hours.
B: Aggregation is not observed after 48 hours, but slight aggregation is observed after 72 hours.
C: Aggregation is not observed after 48 hours, but aggregation is clearly observed after 72 hours.
D: Aggregation is observed within 48 hours.

Test Example 5 [Durability]
Toner is mounted on a non-magnetic one-component development system "OKI Microline 18" (Oki Data Co., Ltd.) and resists diagonal stripe patterns with a blackening rate of 5.5% under conditions of a temperature of 32 ° C and a humidity of 85%. I made a print. On the way, a black solid image was printed every 500 sheets, and streaks on the image were confirmed. The number of printed sheets up to the time when a streak was visually observed on the image was defined as the number of printed sheets, and the durability was evaluated according to the following criteria. The results are shown in Table 4.

〔Evaluation criteria〕
A: The number of printing sheets is 5000 or more. B: The number of printing sheets is 2000 or more and less than 5000. C: The number of printing sheets is less than 2000.

  From the above results, the toner of Comparative Example 1 containing a hybrid resin using an aliphatic polyhydric alcohol other than the alcohol A compared with the toners of Examples 1 to 13 has good durability. It can be seen that the performance is lacking. In addition, the toner of Comparative Example 2 containing a polyester using an aromatic polyhydric alcohol without using alcohol A has insufficient performance, and a polyester using an aliphatic polyhydric alcohol other than alcohol A is used. It can be seen that the toner of Comparative Example 3 contained has good low-temperature fixability but lacks other properties.

  The toner for electrophotography of the present invention is suitably used for developing a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method and the like.

Claims (6)

  An electrophotographic toner obtained by a method comprising a step of granulating a raw material containing a binder resin in an aqueous medium, wherein the binder resin contains a composite resin containing a condensation polymerization resin and a styrene resin The polycondensation resin is obtained by polycondensing an alcohol component containing an aliphatic polyhydric alcohol (alcohol A) having two or more secondary carbon atoms bonded with a hydroxyl group and a carboxylic acid component. An electrophotographic toner, which is a resin that can be obtained.   The alcohol A is an aliphatic polyhydric alcohol having 4 to 8 carbon atoms and having one or more pairs of secondary carbon atoms in which secondary carbon atoms bonded with hydroxyl groups are adjacent to each other. The toner for electrophotography as described.   The toner for electrophotography according to claim 1 or 2, wherein the content of alcohol A is 10 to 100 mol% in the alcohol component.   The toner for electrophotography according to any one of claims 1 to 3, wherein the alcohol component further contains an aliphatic diol having 2 to 8 carbon atoms other than alcohol A.   The toner for electrophotography according to any one of claims 1 to 4, wherein the carboxylic acid component contains 0.1 to 30 mol% of a trivalent or higher polyvalent carboxylic acid compound.   The amount of alcohol A used in the condensation polymerization of the alcohol component and carboxylic acid component is 6 to 100 parts by weight with respect to 100 parts by weight of the total amount of alcohol components and carboxylic acid components other than alcohol A. The toner for electrophotography according to any one of?