JP2010145633A - Electrophotography toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotography toner and a method for manufacturing the toner having excellent low temperature fixability and chargeability as well as excellent pulverizing property, and to provide a crystalline polyester to be used for the toner. <P>SOLUTION: The crystalline polyester is obtained by condensation polymerization of an alcohol component and a carboxylic acid component containing an aromatic dicarboxylic acid compound by 50 to 97 mol% and an unsaturated aliphatic dicarboxylic acid compound by 3 to 50 mol%, wherein the polyester is crosslinked by the unsaturated aliphatic dicarboxylic acid compound. Thus, the crystalline polyester and a manufacturing method thereof are provided. The electrophotography toner containing a binder resin for toner containing the crystalline polyester and an amorphous polyester, and a method for manufacturing the toner are provided. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrophotographic toner used in an electrophotographic method, an electrostatic recording method, an electrostatic printing method, and the like, a manufacturing method thereof, and a crystalline polyester used in the toner.

  In recent years, crystalline polyester has a sharp melt property in which a crystal part is expressed, and is compatible with an amorphous polyester unlike other crystalline resins such as polyethylene, and is easily dispersed. Has attracted attention as a binder resin suitable for improving low-temperature fixability

  In Patent Document 1, the problem is to provide a toner for electrophotography having a wide fixing latitude that is spherical, excellent in fixing property at low temperature, and excellent in offset resistance in a wide temperature range. An electrophotographic toner comprising a colorant, wherein the binder resin contains a crystalline polyester having a crosslinked structure with an unsaturated site as a main component, and toner particles are spherical. Is disclosed.

Patent Document 2 provides a toner for developing an electrostatic charge image suitable for a fixing device that has low-temperature fixability, high-temperature offset resistance, heat-resistant storage stability, and colorant dispersibility, and can achieve an energy saving level unprecedented. An electrostatic charge image developing toner comprising at least a binder resin, a colorant, and a wax, wherein the binder resin has a site capable of reacting with at least a polyester resin and a compound having an active hydrogen group. The polyester resin has a THF soluble content of 50 to 85% by weight and a chloroform insoluble content of 0 to 30% by weight, and the chloroform insoluble content of the toner itself is within a specific range. An electrostatic charge image developing toner is disclosed.
JP 2001-117268 A JP-A-2005-37901

  A toner containing a crystalline polyester using an aromatic dicarboxylic acid compound as a carboxylic acid component is excellent in chargeability but has low grindability.

  An object of the present invention is to provide an electrophotographic toner that has excellent low-temperature fixability and chargeability, and is excellent in grindability, a method for producing the same, and a crystalline polyester used in the toner.

The present invention
[1] A crystalline polyester obtained by condensation polymerization of an alcohol component and a carboxylic acid component containing 50 to 97 mol% of an aromatic dicarboxylic acid compound and 3 to 50 mol% of an unsaturated aliphatic dicarboxylic acid compound. A crystalline polyester crosslinked with the unsaturated aliphatic dicarboxylic acid compound,
[2] Step 1: A step of polycondensing an alcohol component and a carboxylic acid component containing 50 to 97 mol% of an aromatic dicarboxylic acid compound and 3 to 40 mol% of an unsaturated aliphatic dicarboxylic acid compound,
Step 2: A method for producing a crystalline polyester, comprising a step of adding a radical polymerization initiator to obtain a crystalline polyester during or after the condensation polymerization in Step 1;
[3] An electrophotographic toner comprising a toner binder resin containing the crystalline polyester and the amorphous polyester described in [1], and [4] the crystalline polyester described in [1] The present invention relates to a method for producing an electrophotographic toner including a step of melt-kneading a toner raw material containing amorphous polyester.

  The toner for electrophotography of the present invention has the effect of being excellent in low-temperature fixability, chargeability and grindability.

  A crystalline polyester using an aromatic dicarboxylic acid compound as a carboxylic acid component has high compatibility with an amorphous polyester using an alkylene oxide adduct of bisphenol A or an amorphous polyester using an aromatic dicarboxylic acid compound. When melt-kneaded with these amorphous polyesters, they tend to be excessively compatible. Therefore, the recrystallization of the crystalline polyester in the binder resin is slow, and in particular, the crystallization is insufficient at the time of pulverization after melt-kneading, and the pulverizability is lowered. However, in the present invention, it is possible to obtain a toner having good pulverizability by using an unsaturated aliphatic dicarboxylic acid compound and using a crystalline polyester partially crosslinked by an unsaturated bond portion of the compound. I found it. This is because the crystalline polyester can be cross-linked at the unsaturated bond portion of the unsaturated aliphatic dicarboxylic acid compound to increase the molecular weight while maintaining the crystal structure. This is probably because recrystallization is promoted. On the other hand, when cross-linking is performed using a trivalent or higher polyvalent monomer, it is considered that the recrystallization is not promoted because the crystal structure is destroyed.

  The crystalline polyester of the present invention is crosslinked with an unsaturated aliphatic dicarboxylic acid compound. Accordingly, the crystalline polyester of the present invention is preferably obtained using a radical polymerization initiator, and a multimer obtained by subjecting an unsaturated aliphatic dicarboxylic compound to an addition polymerization reaction using a radical polymerization initiator. It is preferable that the polycondensation reaction product is contained. The multimer may be a dimer or a multimer higher than a trimer, but preferably contains a dimer component from the viewpoint of low-temperature fixability and grindability. Dimer component of unsaturated aliphatic dicarboxylic acid compound in crystalline polyester (bonding between unsaturated aliphatic dicarboxylic acid compounds) is a pyrolysis gas chromatograph mass spectrometer (pyrolysis GC / MS) as described later It can be detected by measuring.

  The crystallinity of polyester is expressed by the ratio between the softening point and the highest endothermic peak temperature measured by a differential scanning calorimeter, that is, the softening point / the highest endothermic peak temperature. Generally, when this value exceeds 1.4, the resin is amorphous. When the ratio is less than 0.6, the crystallinity is low and there are many amorphous parts. The crystallinity of the resin can be adjusted by the type and ratio of the raw material monomers, production conditions (for example, reaction temperature, reaction time, cooling rate) and the like. In the present invention, “crystalline polyester” means a polyester having a maximum softening point / endothermic peak temperature value of 0.6 to 1.4, preferably 0.8 to 1.2, and “amorphous polyester” means a softening point / A polyester having a maximum endothermic peak temperature value greater than 1.4 or less than 0.6, preferably greater than 1.4. The highest endothermic peak temperature refers to the temperature of the peak on the highest temperature side among the observed endothermic peaks. If the maximum peak temperature is within ± 20 ° C. of the softening point, the peak temperature is taken as the melting point, and the peak whose difference from the softening point exceeds 20 ° C. is a peak resulting from the glass transition. In the present invention, the term “polyester” means both crystalline polyester and amorphous polyester.

  As described above, the crystalline polyester of the present invention is a crystalline polyester obtained by polycondensing an alcohol component and a carboxylic acid component containing an aromatic dicarboxylic acid compound and an unsaturated aliphatic dicarboxylic acid compound, It is crosslinked with the unsaturated aliphatic dicarboxylic acid compound using a radical polymerization initiator.

  The alcohol component preferably contains an aliphatic diol from the viewpoint of crystallinity.

  Aliphatic diols include ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol From the viewpoint of the crystallinity of the crystalline polyester, the low-temperature fixability of the toner, and the grindability, the carbon number is 2 to 10, preferably the carbon number is 4 to 10, more preferably the carbon number is 4 to 8, and more preferably Aliphatic diols having 6 to 8 carbon atoms are preferred, and α, ω-linear alkane diols are preferred. Thus, more preferred aliphatic diols include 1,6-hexanediol.

  The content of the aliphatic diol having 2 to 10 carbon atoms, preferably 4 to 10 carbon atoms, more preferably 4 to 8 carbon atoms, more preferably 6 to 8 carbon atoms is the same as the above in the alcohol component. 70-100 mol% is preferable, 90-100 mol% is more preferable, 95-100 mol% is further more preferable.

  The content of the trihydric or higher polyhydric alcohol component is preferably 5 mol% or less, more preferably 3 mol% or less, and still more preferably 1 mol% or less in the alcohol component from the viewpoint of toner pulverization.

  Examples of the trihydric or higher polyhydric alcohol component include glycerin and trimethylolpropane.

  In the carboxylic acid component, the content of the aromatic dicarboxylic acid compound is 50 to 97 mol%, preferably 65 to 95 mol%, more preferably 70 to 90 mol%, from the viewpoint of chargeability of the toner.

  Preferred examples of the aromatic dicarboxylic acid compound used in the present invention include aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid, anhydrides of these acids, and alkyl (C1-3) esters thereof. It is done. Examples of the alkyl group of the ester include a methyl group, an ethyl group, a propyl group, and an isopropyl group. Among these, terephthalic acid or an alkyl (C1-3) ester thereof is preferable from the viewpoint of charging stability and low-temperature fixability.

  Further, the content of the unsaturated aliphatic dicarboxylic acid compound is 3 to 50 mol%, preferably 3 to 35 mol%, more preferably 5 to 30 mol%, and still more preferably, from the viewpoint of the pulverizability of the polyester. 10 to 30 mol%.

  As the unsaturated aliphatic dicarboxylic acid compound, dicarboxylic acid compounds such as maleic acid, fumaric acid, citraconic acid, glutaconic acid, itaconic acid, anhydrides of these acids and alkyl (C1-3) esters are preferable. Among them, from the viewpoint of crystallinity, at least one selected from the group consisting of fumaric acid, maleic acid, anhydrides of these acids and alkyl (C1-3) esters is preferred, and fumaric acid is more preferred. . In the present invention, the above-mentioned acids, anhydrides of these acids, and alkyl (C1-3) esters of the acids are collectively referred to herein as carboxylic acid compounds.

  Examples of dicarboxylic acid compounds other than aromatic dicarboxylic acid compounds and unsaturated aliphatic dicarboxylic acid compounds include oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, n-dodecyl succinic acid, n-dodecenyl succinic acid, Examples include cyclohexanedicarboxylic acid, anhydrides of these acids, and alkyl (carbon number 1 to 3) esters.

  Examples of the trivalent or higher polyvalent carboxylic acid compounds include trimellitic acid, pyromellitic acid, anhydrides of these acids, and alkyl (carbon number 1 to 3) esters.

  In the carboxylic acid component, the trivalent or higher polyvalent carboxylic acid compound is not contained or has a content of 5 mol% or less, preferably 3 mol% or less, from the viewpoint of toner pulverization. More preferably, it is 1 mol% or less.

The crystalline polyester of the present invention is obtained by adding a radical polymerization initiator during or after condensation polymerization of an alcohol component and a carboxylic acid component. That is,
Step 1: a step of polycondensing an alcohol component and a carboxylic acid component containing 50 to 97 mol% of an aromatic dicarboxylic acid compound and 3 to 40 mol% of an unsaturated aliphatic dicarboxylic acid compound,
Step 2: The crystalline polyester of the present invention is obtained by a method including a step of obtaining a crystalline polyester by adding a radical polymerization initiator during or after the condensation polymerization in Step 1.

  In Step 1, 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 or a titanium compound, and the temperature thereof is 120 to 120. 230 ° C is preferred.

  In a more preferred embodiment, from the viewpoint of reactivity, the alcohol component and the aromatic dicarboxylic acid compound are first subjected to a polycondensation reaction, preferably at 180 to 230 ° C., and then the unsaturated aliphatic dicarboxylic compound is added to the alcohol. From the viewpoint of suppressing the generation of the trimer of the unsaturated aliphatic dicarboxylic acid compound, the component, the aromatic dicarboxylic acid compound, and the unsaturated aliphatic dicarboxylic compound, preferably 120 ° C. to 180 ° C., more preferably 140 to In this method, a polycondensation reaction is performed at 170 ° C.

  In addition, it is preferable not to use a polymerization inhibitor etc. at the process 1 from a viewpoint of accelerating | stimulating the bridge | crosslinking by an unsaturated aliphatic dicarboxylic compound.

A well-known thing can be used for an esterification catalyst. As the tin compound, fatty acid tin (II) represented by (R ¹ COO) ₂ Sn (where R ¹ represents an alkyl group or alkenyl group having 5 to 19 carbon atoms), (R ² O) ₂ Sn ( R ² represents an alkyl group or an alkenyl group having 6 to 20 carbon atoms), and tin (II) oxide represented by SnO is preferable, and (R ¹ COO) ₂ Sn Fatty acid tin (II) and tin oxide (II) represented are more preferable, tin (II) octoate, tin (II) 2-ethylhexanoate, tin (II) stearate and tin (II) oxide are more 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.

  The above tin compounds and titanium compounds can be used alone or in combination of two or more.

  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.

  In the present invention, from the viewpoint of promoting the ester reaction, a pyrogallol compound having a benzene ring in which three hydrogen atoms adjacent to each other are substituted with a hydroxyl group can be used as a cocatalyst together with the esterification catalyst.

  Examples of the pyrogallol compound include pyrogallol, gallic acid, gallic acid ester, 2,3,4-trihydroxybenzophenone, benzophenone derivatives such as 2,2 ′, 3,4-tetrahydroxybenzophenone, epigallocatechin, and epigallocatechin gallate. Among these, from the viewpoint of the durability of the resulting resin, the formula (I):

Wherein R ^{3 to} R ⁵ are each independently a hydrogen atom or —COOR ⁶ (R ⁶ is a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, preferably an alkyl group or carbon having 1 to 12 carbon atoms. Represents an alkenyl group of 2 to 12)
The compound represented by these is preferable. In the formula, the hydrocarbon group of R ⁶ preferably has 1 to 8 carbon atoms, and more preferably 1 to 4 carbon atoms from the viewpoint of reaction activity. Among the compounds represented by the formula (I), a compound in which R ³ and R ⁵ are hydrogen atoms and R ⁴ is a hydrogen atom or —COOR ⁶ is more preferable. Specific examples include pyrogallol (R ^{3 to} R ⁵ : hydrogen atom), gallic acid (R ³ and R ⁵ : hydrogen atom, R ⁴ : —COOH), ethyl gallate (R ³ and R ⁵ : hydrogen atom, R ⁴ : —COOC ₂ H ₅ ), propyl gallate (R ³ and R ⁵ : hydrogen atom, R ⁴ : —COOC ₃ H ₇ ), butyl gallate (R ³ and R ⁵ : hydrogen atom, R ⁴ : —COOC) ₄ H _9), octyl gallate (R ³ and R ^5: a hydrogen _{^{atom, R 4: -COOC 8 H 17}} ), lauryl gallate (R ³ and R ^5: a hydrogen _{^{atom, R 4: -COOC 12 H 25}} ) And gallic acid esters. From the viewpoint of the durability of the resin, gallic acid and gallic acid ester are preferable.

  The amount of the pyrogallol compound in the condensation polymerization reaction is preferably 0.001 to 1.0 part by weight, more preferably 0.005 to 0.4 part by weight, and 0.01 to 0.2 part by weight with respect to 100 parts by weight of the raw material monomer to be subjected to the condensation polymerization reaction. Further preferred.

  In the crystalline polyester, the molar ratio of the carboxylic acid component to the alcohol component (carboxylic acid component / alcohol component) is preferably 0.9 or more and less than 1.0, and more preferably 0.95 or more and less than 1.0.

  In Step 2, the radical polymerization initiator may be present in the reaction system immediately after the start of the condensation polymerization reaction in Step 1, but reaction control (suppresses the formation of multimers of trimers or more and is insoluble in chloroform. The reaction rate of the condensation polymerization reaction is preferably 40 to 100%, more preferably 50 to 90% when the theoretical reaction water discharge is 100%. It is desirable to add it at the time when it is applied.

  In the polycondensation reaction, all monomers are charged at once in order to increase the strength of the resin, or a divalent monomer is first reacted in order to reduce low molecular weight components. You may use the method of adding a monomer and making it react. Further, the reaction may be accelerated by reducing the pressure of the reaction system in the latter half of the polymerization.

  Examples of radical polymerization initiators include azo compounds such as 2,2′-azobisisobutyronitrile and 2,2′-azobis (2,4-dimethylvaleronitrile), dibutyl peroxide, dicumyl peroxide, and tartaric acid. Well-known radical polymerization initiators, such as organic peroxides, such as a butyl peroxy 2-ethylhexyl monocarbonate, are mentioned.

  The amount of the radical polymerization initiator used is preferably 0.01 to 10 parts by weight, more preferably 0.01 to 2 parts by weight, more preferably 0.02 to 1 part per 100 parts by weight of the total amount of the alcohol component and carboxylic acid component used in the condensation polymerization reaction. Parts by weight are more preferred, 0.03 to 0.5 parts by weight are still more preferred, and 0.02 to 50 parts by weight are preferred, 0.02 to 10 parts by weight are more preferred, and 0.05 to 7 parts per 100 parts by weight of the unsaturated aliphatic dicarboxylic acid compound. Part by weight is more preferred, and 0.1 to 5 parts by weight is even more preferred.

  The reaction temperature is preferably from 80 to 180 ° C, more preferably from 80 to 160 ° C, from the viewpoint of proceeding the addition polymerization reaction with the radical polymerization initiator.

  Although depending on the reaction scale, the reaction time is usually preferably from 30 minutes to 5 hours, more preferably from 30 minutes to 3 hours.

  From the viewpoint of toner pulverization, it is preferable to perform a condensation polymerization reaction after the addition polymerization reaction. In that case, the reaction temperature is preferably 190 to 230 ° C, more preferably 190 to 210 ° C. In that case, it is preferable to add a polymerization inhibitor such as tertiary butyl catechol from the viewpoint of preventing the decomposition of the crosslinked product of the addition polymer of the unsaturated aliphatic dicarboxylic acid compound.

  The melting point of the crystalline polyester is preferably 70 to 140 ° C., more preferably 80 to 130 ° C., and still more preferably 90 to 115 ° C., from the viewpoint of low-temperature fixability of the toner. The melting point of the crystalline polyester can be determined as the maximum peak temperature of the endothermic resin described later.

  The softening point of the crystalline polyester is preferably 60 to 130 ° C., more preferably 70 to 125 ° C., and still more preferably 85 to 120 ° C. from the viewpoint of low-temperature fixability of the toner. The melting point and softening point of the crystalline polyester can be easily adjusted by adjusting the raw material monomer composition, the polymerization initiator, the molecular weight, the catalyst amount, etc., or by selecting the reaction conditions. The softening point varies depending on the monomer composition of the resin, but even with the same monomer composition, the softening point can be increased by increasing the reaction time, increasing the reaction temperature, and increasing the molecular weight. .

  In the crystalline polyester of the present invention, the content of the chloroform insoluble component is preferably 0 to 30% by weight, more preferably 0 to 20% by weight, and more preferably 1 to 10% by weight from the viewpoints of toner grindability and low-temperature fixability. Is more preferable, and 1 to 3% by weight is even more preferable. The chloroform-insoluble content of the crystalline polyester can be controlled by increasing the reaction time or increasing the reaction temperature to make the polymer higher and increasing the storage elastic modulus of the resin. That is, the chloroform insoluble matter can be increased by increasing the storage elastic modulus of the resin described later. Furthermore, it can also be controlled by adjusting the amount of radical polymerization initiator, and the content of chloroform insolubles can be increased by increasing the amount used.

  The storage elastic modulus (G ′ [160 ° C.] (Pa)) of the crystalline polyester at 160 ° C. is preferably 100 Pa or more from the viewpoint of the charging property and grindability of the toner, and from the viewpoint of low-temperature fixability and grindability of the toner. From these viewpoints, it is preferably 100 to 100,000 Pa, more preferably 100 to 10,000 Pa, and further preferably 500 to 10,000 Pa. The storage elastic modulus of the resin is considered to correlate with the molecular weight of the resin, and can be increased by increasing the reaction time or increasing the reaction temperature to increase the molecular weight.

  The binder resin of the present invention contains the crystalline polyester and the amorphous polyester.

  Amorphous polyester is also obtained by condensation polymerization of an alcohol component and a carboxylic acid component as raw material monomers, as in the case of crystalline polyester, and the alcohol component is an amorphous resin such as an aromatic diol. It is preferable that the monomer which accelerates | stimulates quality contains.

  Examples of aromatic diols that promote the amorphization of the resin include polyoxypropylene-2,2-bis (4-hydroxyphenyl) propane and polyoxyethylene-2,2-bis (4-hydroxyphenyl) propane. Formula (II):

(In the formula, R ⁷ O and OR ⁷ are oxyalkylene groups, R ⁷ is an ethylene and / or propylene group, x and y indicate the number of added moles of alkylene oxide, each being a positive number, The average value of the sum of y and y is preferably 1 to 16, more preferably 1 to 8, and even more preferably 1.5 to 4)
An alkylene oxide adduct of bisphenol A represented by:

  The content of the alkylene oxide adduct of bisphenol A represented by the formula (II) is preferably 50 mol% or more, more preferably 70 mol% or more, and more preferably 90 mol in the alcohol component from the viewpoint of charge stability of the toner. % Or more is more preferable.

  Examples of the dicarboxylic acid compound contained in the carboxylic acid component include fumaric acid, adipic acid, oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, sebacic acid, azelaic acid, n-dodecyl succinic acid, n-dodecenyl succinic acid and the like having 2 to 30 carbon atoms, preferably 2 to 8 aliphatic dicarboxylic acids; phthalic acid, isophthalic acid, terephthalic acid and other aromatic dicarboxylic acids; cyclohexane dicarboxylic acid and other fats Cyclic dicarboxylic acids; anhydrides of these acids, and alkyl (C1-3) esters of acids.

  In addition, trivalent or higher polyvalent carboxylic acid compounds include trimellitic or higher polyvalent carboxylic acids such as trimellitic acid and pyromellitic acid, anhydrides of these acids, and alkyl alkyls (1 to 3 carbon atoms). Examples include esters.

  A monovalent alcohol may be appropriately contained in the alcohol component, and a monovalent carboxylic acid compound may be appropriately contained in the carboxylic acid component in order to adjust the molecular weight of the resin.

  The amorphous polyester is obtained by subjecting an alcohol component and a carboxylic acid component to condensation polymerization at 180 to 250 ° C., for example, in an inert gas atmosphere, if necessary, in the presence of an esterification catalyst, a polymerization inhibitor or the like.

  The softening point of the amorphous polyester is preferably 90 to 160 ° C., more preferably 95 to 155 ° C., and further preferably 115 to 150 ° C. from the viewpoint of low-temperature fixability and storage stability of the toner.

  In the present invention, from the viewpoint of low-temperature fixability and storage stability of the toner, the amorphous polyester preferably has a softening point of 10 ° C. or higher, more preferably 20 to 60 ° C. It is preferably made of an amorphous polyester having a low softening point. The softening point of the high softening point amorphous polyester is preferably 125 to 160 ° C, more preferably 130 to 150 ° C, and the softening point of the low softening point amorphous polyester is preferably 90 to 120 ° C, more preferably. Is 90-110 ° C. The weight ratio of the high softening point amorphous polyester to the low softening point amorphous polyester (high softening point amorphous polyester / low softening point amorphous polyester) is preferably 1/3 to 3/1, 1/2 ~ 2/1 is more preferred.

  The glass transition point of the amorphous polyester 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 and storage stability of the toner. The glass transition point is a physical property peculiar to an amorphous resin, and is distinguished from the maximum peak temperature of endotherm.

  The acid value of the amorphous polyester 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, from the viewpoint of chargeability and environmental stability of the toner.

  In the present invention, the polyester may be a polyester modified to such an extent that the characteristics are not substantially impaired. 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. And a composite resin having two or more kinds of resin units including a polyester unit.

  In the binder resin, the weight ratio of crystalline polyester to amorphous polyester (crystalline polyester / amorphous polyester) is preferably 10/90 to 40/60 from the viewpoint of low-temperature fixability and chargeability of the toner. 10/90 to 30/70 are more preferable, and 20/80 to 30/70 are more preferable.

  In the binder resin, a resin other than a polyester such as a vinyl resin, an epoxy resin, a polycarbonate, or a polyurethane may be appropriately contained as long as the effects of the present invention are not impaired. The total content of the crystalline polyester and the amorphous polyester is preferably 80% by weight or more, more preferably 90% by weight or more, and still more preferably 100% by weight in the binder resin.

  Further, the toner 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, an anti-aging agent, Additives such as a cleaning property improving agent 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.

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

  As a method for producing the electrophotographic toner of the present invention, a method including a step of melt-kneading the toner raw material containing the crystalline polyester and the amorphous polyester of the present invention is preferable. Since the crystalline polyester of the present invention has low compatibility with the amorphous polyester, even if it is melt-kneaded with the amorphous polyester, a decrease in crystallinity can be suppressed.

  For melt kneading of raw materials, for example, crystalline polyester, amorphous polyester, colorant and the like are appropriately mixed with a mixer such as a Henschel mixer or a super mixer, and then a sealed kneader or a single or twin screw extruder, It can be carried out using a kneader such as an open roll kneader.

  The temperature at the time of melt-kneading is not particularly limited as long as each raw material can be sufficiently mixed, but is preferably (Ta-30) ° C. or more and (Ta + 40) ° C. or less. Here, Ta is a weight average softening point (° C.) obtained by weighted averaging of the softening points of the respective binder resins. Specifically, 90-170 degreeC is preferable and 110-140 degreeC is more preferable.

  After the melt-kneading step, the toner may be obtained by a pulverization method in which a pulverization, classification step or the like is performed. In the present invention, it is preferable to produce a toner by a pulverization method from the viewpoint of chargeability.

The volume median particle size (D ₅₀ ) of the toner of the present invention is preferably 3 to 15 μm, more preferably 3 to 10 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 (manufactured by Shimadzu Corporation, CFT-500D), a 1 g sample was heated at a heating rate of 6 ° C / min, a 1.96 MPa load was applied by a plunger, a nozzle with a diameter of 1 mm and a length of 1 mm Extruded from. 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.

[Maximum peak temperature of resin endotherm]
Using a differential scanning calorimeter (Q-100 Japan, Q-100), let the sample cooled from room temperature to 0 ° C at a cooling rate of 10 ° C / min. Measure up to 150 ° C at a rate of 10 ° C / min. Among the observed endothermic peaks, the temperature of the peak on the highest temperature side is defined as the highest endothermic peak temperature.

[Glass transition point of resin]
Using a differential scanning calorimeter (Q Instruments Japan Co., Ltd., Q-100), weigh 0.01 to 0.02 g of the sample into an aluminum pan, raise the temperature to 200 ° C, and decrease the temperature from that temperature. The sample cooled to 0 ° C at 10 ° C / min is heated at a heating rate of 10 ° C / min, and the maximum slope from the peak rising part to the peak apex is reached. The temperature at the intersection with the indicated tangent is taken as the glass transition point.

[Acid value of the resin]
Measured according to the method of JIS K0070. However, only the measurement solvent is 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.

[Chloroform-insoluble content of resin]
(1) Sample preparation
Using a JIS Z8801 sieve, collect a powder sample that passes through a 22 mesh sieve and does not pass through a 30 mesh sieve. When the sample is a lump or the like, it is pulverized using a commercially available hammer mill or coffee mill and sieved as a powder.

(2) Sample dissolution
2-1. Weigh 2.000 g of the sample in a glass bottle (Made by Yoyo Glass Co., Ltd., M-140), add 95 g of chloroform, and attach the inner and outer lids.
2-2. Stir for 5 hours in a ball mill (peripheral speed: 200 mm / sec).
2-3. Leave for 10 hours.

(3) Filtration
3-1. Prepare a glass filter (aperture standard 11G-3) attached to an eggplant flask (weight A (g)) (100 ml) that has been weighed in advance (weighed to a thousandth of a gram). A rubber stopper that can be decompressed is used to seal the glass filter.
3-2. Absorb 20 ml from the supernatant of the lysate that has been allowed to stand for 10 hours in 2-3 with a mespiped, and filter under reduced pressure using the glass filter prepared in 3-1. The supernatant is 2 cm below the liquid level. The degree of vacuum in the eggplant flask before filtering the solution is adjusted to 40 kPa.
3-3. Absorb 20 ml of unused chloroform with Mespiped, and filter the soluble matter adhering to the glass filter under reduced pressure.

(4) Drying
4-1. Remove the chloroform in the eggplant flask with an evaporator.
Water bath temperature: 70 ℃
Eggplant flask rotation speed: 200r / min
Degree of vacuum in eggplant flask during removal of chloroform: 40 to 20 kPa Adjustment time: 10 minutes
4-2. After drying at 50 ° C. and 1 torr for 12 hours, weigh the eggplant flask B (g) to which the chloroform solubles have adhered.

(5) Calculation of chloroform insoluble matter
5-1. Calculate the chloroform soluble content X (g) dissolved in 20 ml of chloroform.
X = BA
5-2. Calculate the chloroform soluble component Y (g) dissolved in 95 g of chloroform, assuming that the specific gravity of chloroform is 1.485.
Y = X × 95 / (20 × 1.485)
5-3. Calculate the soluble content Z (% by weight) per gram of sample.
Z = Y / 2 × 100
5-4. Insoluble matter in chloroform (% by weight) = 100-Z
Note that the chloroform-insoluble content (% by weight) is the average of three measurements.

[Detection of fumaric acid (FA) dimer component by pyrolysis gas chromatograph mass spectrometer (pyrolysis GC / MS)]
(Measurement condition)
1. Thermal decomposition equipment and conditions Equipment: manufactured by Nihon Analytical Industries, Ltd.
Curie point injector (JSI-22)
Thermal decomposition temperature: 590 ° C
Thermal decomposition time: 5s
2. GC / MS equipment and conditions Equipment: Agilent 6890
Column: HP-5ms (30m × 0.25mm × 0.25μm)
Oven temperature: 40 ° C (5min) -10 ° C / min-300 ° C (20min)
Carrier gas: He (column flow rate: 1.0 mL / min)
Injection method: Split Split ratio 50: 1
Inlet temperature: 300 ° C
Detector (MS): Agilent 5973
MS temperature: Quadrupole: 150 ° C Ion source: 230 ° C
Scanning range: EI (Electron Ionization): m / z (ion mass / charge) 29-500,
2. Detection from 0 min Measurement procedure
1) Sample 200 μg of crystalline polyester on a pyrofoil as a sample.
2) 1 μL of tetramethylammonium hydroxide (TMAH) is dropped on the sample (methyl ester derivatizing agent: ester is decomposed and methylated during thermal decomposition).
3) Seal the sample with pyrofoil and place in a pyrolyzer.
4) Pyrolyze and detect with GC / MS.
4). Measurement Results The peak of the fumaric acid dimer is confirmed by matching the MS spectrum pattern and the detection time with a fumaric acid dimer standard (butanetetracarboxylic acid, Aldrich Co., Ltd.). The detection time of the peak of the dimer of fumaric acid in the example was 20.7 minutes.

[Storage modulus of resin]
The storage elastic modulus (G ′ [160 ° C.]) at 160 ° C. is measured with a rheometer (ARES, manufactured by TA Instruments) (Strain: 0.05%, frequency: 6.28 rad / sec). A parallel plate with a diameter of 25 mm is heated / left at 140 ° C, 1 g of sample is placed on the parallel plate at 140 ° C and sandwiched between the upper and lower plates, then heated up to 180 ° C at 5 ° C / min, and storage elasticity at 160 ° C Find the rate.

[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).

Production Example 1 of Crystalline Polyester [Resins A to G]
Raw material monomers other than fumaric acid shown in Table 1, 40 g of 2-ethylhexanetin (II) (esterification catalyst) and 2 g of gallic acid (cocatalyst) were equipped with a nitrogen introduction tube, dehydration tube, stirrer and thermocouple 10 Place in a 4-liter flask and react at 200 ° C for 10 hours, then cool to 160 ° C, add fumaric acid as shown in Table 1, and react at 160 ° C for 4 hours (reaction rate of fumaric acid 60%). Then, 20 g of dibutyl peroxide (radical polymerization initiator) was added dropwise over 30 minutes, and further maintained at 160 ° C. for 1 hour, and then 5 g of tertiary butyl catechol (polymerization inhibitor) was added at 10 ° C./hr. The temperature was raised to 200 ° C. By reacting at 8.3 kPa until the predetermined melt viscosity shown in Table 1 was obtained, a crystalline polyester was obtained.

Production Example 2 of Crystalline Polyester [Resin H, I]
Equipped with nitrogen introduction tube, dehydration tube, stirrer and thermocouple with raw material monomers other than trimellitic acid shown in Table 2, 40 g of 2-ethylhexanetin (II) (esterification catalyst) and 2 g of gallic acid (cocatalyst) The resultant was put into a 10-liter four-necked flask and reacted at 200 ° C. for 10 hours. Then, trimellitic acid shown in Table 2 was added and reacted for 2 hours. Thereafter, the reaction was allowed to proceed to 8.3 kPa until the predetermined melt viscosity shown in Table 2 was obtained to obtain a crystalline polyester.

Production Example 3 of Crystalline Polyester [Resin J]
The raw material monomers shown in Table 3, 40 g of 2-ethylhexanetin (II) (esterification catalyst) and 5 g of tertiary butylcatechol (polymerization inhibitor) were equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple. The mixture was put into a 4-liter flask having a volume of 1 liter, reacted at 140 ° C. for 4 hours, and then heated to 160 ° C. at 10 ° C./hr. After maintaining at 160 ° C. for 2 hours, the temperature was further raised to 200 ° C. at 10 ° C./hr, and then reacted at 4 kPa for 3 hours to obtain a crystalline polyester.

Amorphous polyester production example 1 [resins a, b]
Raw material monomers other than trimellitic anhydride shown in Table 4 and 40 g of 2-ethylhexane tin (II) (esterification catalyst) are provided in four 10-liter volumes equipped with a nitrogen inlet tube, a dehydrating tube, a stirrer, and a thermocouple. The flask was placed in a neck flask, reacted at 230 ° C. for 8 hours, and then reacted at 8.3 kPa for 1 hour. Further, trimellitic anhydride shown in Table 4 was added at 210 ° C. and reacted until a desired softening point was reached to obtain an amorphous polyester.

Examples 1-8 and Comparative Examples 1-4
The raw materials composed of the composition containing the binder resin shown in Table 6 were thoroughly stirred with a Henschel mixer and then melt-kneaded using 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. . The rotation speed of the roll was 200 r / min, the heating temperature in the roll was 120 ° C., the feed rate of the mixture was 10 kg / hr, and the average residence time was about 18 seconds. The obtained kneaded product was rolled and cooled with a cooling roll, and toner particles having a volume median particle size (D ₅₀ ) of 4.8 μm were obtained with a jet mill.

  External additive `` Aerosil R-972 '' (hydrophobic silica, manufactured by Nippon Aerosil Co., Ltd.) 0.5 part by weight and `` NAX-50 '' (hydrophobic silica, manufactured by Nippon Aerosil Co., Ltd.) 1.0 with respect to 100 parts by weight of the obtained toner particles A toner was obtained by adding parts by weight and mixing with a Henschel mixer at 3600 r / min for 5 minutes.

  The details of the blends A and B shown in Table 6 are as follows.

Test Example 1 [Crushability]
The toner crushed by attaching a 3 mm mesh to a rotoplex was pulverized with a pulverization pressure of 0.5 Pa by an I-2 type pulverizer (manufactured by Nippon Pneumatic Co., Ltd.). The grinding efficiency was determined from the yield obtained per hour, and the grindability was evaluated according to the following evaluation criteria. The results are shown in Table 6.

〔Evaluation criteria〕
A: The grinding efficiency is 2.0 kg / hr or more.
B: The grinding efficiency is 1.5 kg / hr or more and less than 2.0 kg / hr.
C: The grinding efficiency is 1.0 kg / hr or more and less than 1.5 kg / hr.
D: The grinding efficiency is less than 1.0 kg / hr.

Test Example 2 [low temperature fixability]
The toner was mounted on a copying machine “AR-505” (manufactured by Sharp), and an image was printed without fixing (printing area: 2 cm × 12 cm, adhesion amount: 0.5 mg / cm ² ). The fixing machine of the copying machine was fixed on paper at 300 mm / sec while increasing the fixing temperature sequentially from 90 ° C. to 240 ° C. in 5 ° C. increments. As the fixing paper, “CopyBond SF-70NA” (manufactured by Sharp Corporation, 75 g / m ² ) was used.

  “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. Measure the optical reflection density before and after applying the tape using a reflection densitometer “RD-915” (manufactured by Macbeth Co.), and the ratio of both (after peeling / before sticking) first exceeds 90%. The temperature of the roll was set as the minimum fixing temperature, and the low temperature fixing property was evaluated according to the following evaluation criteria. The results are shown in Table 6.

〔Evaluation criteria〕
A: The minimum fixing temperature is less than 120 ° C.
B: The minimum fixing temperature is 120 ° C. or higher and lower than 135 ° C.
C: The minimum fixing temperature is 135 ° C. or higher and lower than 150 ° C.
D: The minimum fixing temperature is 150 ° C. or higher.

Test Example 3 [Chargeability]
0.6g of toner and 19.4g of silicone ferrite carrier (manufactured by Kanto Denka Kogyo Co., Ltd., volume average particle size 90μm) are placed in a 50ml plastic bottle, mixed at 400r / min using a ball mill, and the charge amount is q / m meter (EPPING) was used for measurement. Calculate the ratio of the charge amount after 300 seconds mixing time and the charge amount after 3600 seconds mixing time (charge amount after 3600 seconds mixing time / charge amount after 300 seconds mixing time) and charge stability according to the following evaluation criteria Sex was evaluated. The results are shown in Table 6.

〔Evaluation criteria〕
A: 0.8 or more B: 0.6 or more and less than 0.8 C: Less than 0.6

  From the above results, it can be seen that in Examples 1-8, toners excellent in low-temperature fixability and chargeability can be produced with good productivity as compared with Comparative Examples 1-4.

  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 (8)

  A crystalline polyester obtained by condensation polymerization of an alcohol component and a carboxylic acid component containing 50 to 97 mol% of an aromatic dicarboxylic acid compound and 3 to 50 mol% of an unsaturated aliphatic dicarboxylic acid compound, A crystalline polyester obtained by crosslinking with an unsaturated aliphatic dicarboxylic acid compound.   The crystal according to claim 1, wherein the unsaturated aliphatic dicarboxylic acid compound is at least one selected from the group consisting of fumaric acid, maleic acid, anhydrides of these acids, and alkyl (C1-3) esters. Polyester.   The crystalline polyester according to claim 1 or 2, wherein a dimer of an unsaturated aliphatic dicarboxylic acid compound is detected in a pyrolysis gas chromatograph mass spectrometer.   The crystalline polyester according to any one of claims 1 to 3, wherein the alcohol component contains an aliphatic diol having 2 to 10 carbon atoms.   The crystalline polyester according to any one of claims 1 to 4, wherein the content of a trivalent or higher polyvalent carboxylic acid compound in the carboxylic acid component is 5 mol% or less. Step 1: a step of polycondensing an alcohol component and a carboxylic acid component containing 50 to 97 mol% of an aromatic dicarboxylic acid compound and 3 to 40 mol% of an unsaturated aliphatic dicarboxylic acid compound,
Step 2: A method for producing a crystalline polyester, comprising a step of obtaining a crystalline polyester by adding a radical polymerization initiator during or after the condensation polymerization in Step 1.   An electrophotographic toner comprising the toner binder resin containing the crystalline polyester and the amorphous polyester according to claim 1.   A method for producing an electrophotographic toner, comprising a step of melt-kneading a toner raw material containing the crystalline polyester and the amorphous polyester according to claim 1.