JP2005157074A - Method for producing polyester resin for toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a polyester resin for toner by which the polyester resin can be efficiently mass-produced with stable quality without using bisphenol A or its derivative as an alcohol component. <P>SOLUTION: The polyester resin is synthesized in which acid components are (1) disproportioned rosin and (2) terephthalic acid and/or isophthalic acid, alcohol components are (3) glycidyl ester and (4) an aliphatic diol, a crosslinking component consists of a polycarboxylic acid and/or a polyol, a molar ratio between the acid components (1)/(2) is 0.2-0.6, and a molar ratio between the alcohol components (3)/(4) is 0.05-0.4. The polyester resin is discharged from a reactor vessel under conditions of 160-250°C, a viscosity of 3-400 Pa s at the start of discharge and a viscosity of 50-500 Pa s at an end, and after cooling and pulverization, the resulting pulverized powder is mixed using a mixer and made uniform. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electrostatic charge image for developing an electrostatic charge image in an electrophotographic copying machine, a laser beam printer, an electrostatic recording apparatus or the like in which an image is formed using an electrophotographic method, an electrostatic recording method, or the like. The present invention relates to a method for producing a polyester resin for toner used in developing toner.

  Conventionally, the electrophotographic method or the electrostatic recording method has been widely used as a method for obtaining a copy or recorded image in a copying machine for copying an original or a printer for outputting a computer including a personal computer or a printer for a facsimile receiving apparatus. Has been. Typical examples of the copying machine and printer using the electrophotographic method or the electrostatic recording method include an electrophotographic copying machine, a laser beam printer, a printer using a liquid crystal array, and an electrostatic printer. In the electrophotographic method or the electrostatic recording method, an electrostatic latent image (electrostatic image) is formed by various means on an electrostatic image carrier such as an electrophotographic photosensitive member or an electrostatic recording member. While developing the image with a developer, the obtained toner image is transferred to a transfer medium such as paper as necessary, and fixed by heating, pressing, heating and pressing, or solvent vapor to obtain a final toner image The toner remaining without being transferred onto the electrostatic image bearing member is removed by the cleaning means. By repeating these steps, a plurality of copies or records can be obtained sequentially.

  As a method for developing the electrostatic latent image, a method using a liquid developer in which a fine toner is dispersed in an electrically insulating liquid (wet development method), a colorant in a binder resin, and a magnetic material as necessary. A method of using dispersed powder toner together with carrier particles, a method of developing without using carrier particles using a magnetic toner in which a magnetic material is dispersed in a binder resin (dry development method), etc. are known. . Among these methods, in recent years, a dry development method using powder toner is mainly employed.

  By the way, in recent years, electrophotographic copying machines, laser beam printers, and the like have become smaller and more personalized, and at the same time, higher speed has been required, and further reduction in energy has been required. Therefore, various attempts have been made to improve these apparatuses for forming a reliable and high-quality image at high speed and with low energy over a long period of time using a mechanism as simple as possible. In addition to such improvements in the apparatus, various attempts have been made to improve the toner and toner binder resin used in development.

  The proportion of the binder resin in the toner composition is very large, and the properties of the binder resin have a very large influence on the properties of the toner. Among them, what is required for the binder resin is offset resistance, low-temperature fixability, blocking resistance, sharp melt property, charging property, pulverization property, transparency and the like.

  As the binder resin having excellent offset resistance, for example, a cross-linked polyester resin (for example, obtained by reacting an etherified diphenol, a dicarboxylic acid component, and a trivalent or higher monomer component to form a cross-linked structure (for example, ), Etherified diphenol, dicarboxylic acid component containing a specific dicarboxylic acid, and trivalent or higher monomer component containing trimellitic anhydride to react to form a crosslinked structure. Type polyester resins (for example, see Patent Document 2) are known, but the low-temperature fixability is not always good.

  On the other hand, from the viewpoint of improving the low-temperature fixability of the toner, it is effective to lower the softening temperature (Tm) of the toner binder resin. However, it is known that when Tm is lowered, the glass transition temperature (Tg) of the toner is also lowered at the same time, so that the toner forms a lump in the storage state, and so-called toner blocking and toner offset at the time of fixing easily occur. This is one of the reasons why the fixing temperature cannot be lowered as expected. As a method for simultaneously satisfying this low-temperature fixability and blocking resistance or offset resistance, a method using a polyester resin having a relatively low fixing temperature even when Tm or Tg is high (for example, see Patent Document 3) has been proposed. ing. However, this method does not satisfy the low-temperature fixing property, blocking resistance, offset resistance and the like simultaneously and sufficiently. In addition, examples in which alkylene glycol and etherified diphenol are used in combination as an alcohol component of a polyester resin are also known (see, for example, Patent Documents 4 and 5), but the toner is not sufficiently pulverizable or has a low Tg. The blocking resistance of the obtained toner is not satisfactory. In addition, a dihydric alcohol is used as the alcohol component, and a non-linear cross-linked polyester resin composed of rosin, unsaturated dicarboxylic acid and other dicarboxylic acid as the acid component (see, for example, Patent Document 6), a specific alcohol component or Examples using acid components (see, for example, Patent Documents 7, 8, 9), examples using block polymers (see, for example, Patent Document 10), examples using amorphous polyester and crystalline polyester in combination (for example, Patents) A large number of polyester resins for toner binders have been proposed, such as offset resistance, low temperature fixability, sharp melt properties, blocking resistance, charging properties, pulverization properties, and transparency required as toner properties. Development of a resin for toner that can simultaneously satisfy the characteristics has been made.

JP-A-1-155362 JP-A-57-109825 JP-A-56-1952 Japanese Patent Laid-Open No. 1-226761 JP-A-1-155360 JP-A-4-70765 Japanese Patent Laid-Open No. 6-27728 Japanese Patent Laid-Open No. 9-278872 Japanese Patent Laid-Open No. 10-268558 JP 2001-324832 A JP 2002-284866 A

  As described above, attempts have been made to produce a toner for developing an electrostatic charge image with good characteristics by using a polyester resin as a binder resin for the toner. Conventionally, a polyester binder resin for toner with good toner characteristics has been used. When obtaining, generally, bisphenol A or a derivative thereof is used as an alcohol component. However, in recent years, it has become clear that bisphenol A is not necessarily used from the viewpoint of environmental hormones, and without using bisphenol A or its derivatives, offset resistance, low-temperature fixability, and sharp melt properties are the same as before. Development of a polyester resin for toner that is excellent in properties such as blocking resistance, charging properties, pulverization properties, and transparency and that can form a good developed image over a long period of time is desired.

  Furthermore, recently, the economics of toner has also been regarded as important, and there has been a demand for provision of an inexpensive toner binder resin. However, conventional toner binders cannot always meet such demands. .

  In addition, from the viewpoint of resource saving, a toner binder that can be used for a toner for developing an electrostatic charge image that forms an image having a high density similar to the conventional one with a small amount of toner is also desired.

  On the other hand, after synthesizing the polyester resin, when the polyester is taken out from the reaction vessel and commercialized, the resin discharged after synthesis is removed from the steel belt cooler, drum cooler, water-cooled bat type cooling device, roll cooler, etc. The resin is cooled by a cooling device, and the resin is cured, and is pulverized to an average particle size of 0.02 to 15 mm by a pulverizer such as a pin mill, a roll mill, or a hammer mill (see, for example, Patent Document 12). Further, the coarsely pulverized resin is further finely pulverized and then mixed with a mixer such as a conical screw mixer (for example, see Patent Document 13). In addition, when synthesizing a non-linear polyester resin with a large amount of cross-linking component, when the resin is taken out from the reaction vessel and commercialized after synthesis, it takes time to discharge the resin. This causes a problem that the state of the resin changes, for example, the gelation of the polyester resin or the molecular weight of the taken-out resin changes with time. For this reason, even if there is no problem in the synthesis of polyester resin itself in the laboratory scale, in order to obtain a polyester resin product that is always scaled up and mass-produced in an industrially stable state and has a stable quality, the resin is discharged and taken out. Although it is necessary to optimize the conditions, it is difficult to set the optimization conditions at present.

JP 2001-330994 A (page 9) Japanese Patent Laid-Open No. 2-71275 (page 4)

  In view of such a current situation, the object of the present invention is to provide excellent anti-offset property in fixing by a heat roller fixing or fixing belt system without using bisphenol A or a derivative thereof as an alcohol component, as well as low temperature fixability, sharp melt Toner having excellent properties such as property, blocking resistance, charging property, pulverization property, transparency, and low consumption, and capable of forming a good developed image over a long period of time. It is providing the manufacturing method of the polyester resin for water.

  Another object of the present invention is to provide a method for producing a polyester resin for toner, which can efficiently produce a polyester resin for toner that does not use bisphenol A or a derivative thereof as an alcohol component with stable quality. It is.

  Another object of the present invention is to provide a method for producing a polyester resin for toner that is excellent in properties as a binder resin for toner and is inexpensive.

  In the present invention, the acid component is (1) disproportionated rosin and (2) terephthalic acid and / or isophthalic acid, and the alcohol component is (3) a glycidyl ester of a tertiary fatty acid and (4) having 2 to 10 carbon atoms. The aliphatic diol, the crosslinking component is composed of a trivalent or higher polycarboxylic acid and / or a trivalent or higher polyol, and the molar ratio (1) / (2) of the acid components (1) and (2) is 0.2. In a reaction vessel having a lower portion of a polyester resin having a molar ratio (3) / (4) of the alcohol components (3) and (4) of 0.05 to 0.4. The polyester resin synthesized is then discharged from the reaction vessel at a polyester resin temperature of 160 to 250 ° C., a viscosity at the start of discharge of 3 to 400 Pa · s, and a viscosity at the end of discharge of 50 to 500 Pa · s. Before discharge The polyester resin cooling, was ground to a method for producing a polyester resin for a toner, characterized by further mixing and homogenizing the ground product using a mixer.

  In the cooling process, the discharged polyester resin is 10 J / g · min. The present invention relates to a method for producing a polyester resin for toner, wherein the toner is cooled to 100 ° C. or lower at the above cooling rate.

  Furthermore, the present invention relates to a method for producing a polyester resin for toner, wherein the inside of a reaction vessel is pressurized with an inert gas when discharged.

  The present invention also relates to the above-described method for producing a polyester resin for toner, wherein the polyester resin after pulverization has a tetrahydrofuran (THF) insoluble content of 50% or less.

The present invention also relates to a method for producing the above polyester resin for toner, wherein the true density of the pulverized polyester resin is 1.1 to 1.3 g / cm ³ .

  The present invention also relates to the above-described method for producing a polyester resin for toner, wherein rosin glycidyl ester is further contained as an alcohol component.

  In the polyester resin for toner according to any one of claims 1 to 6, wherein the difference between the viscosity of the resin at the start of discharging and the viscosity of the resin at the end of discharging is 400 Pa · s or less. It relates to a manufacturing method.

  Hereinafter, the present invention will be described in more detail. First, in the method for producing a polyester resin for toner of the present invention, the polyester resin is used as (a) acid component, disproportionated rosin (1) and terephthalic acid and / or isophthalic acid (2), (b) alcohol component. , A glycidyl ester of a tertiary fatty acid (3), an aliphatic diol having 2 to 10 carbon atoms (4), and (c) a tricarboxylic or higher polycarboxylic acid and / or a trivalent or higher polyol as a crosslinking component. Synthesized.

In the present invention, the disproportionated rosin used as the acid component of (a) may be produced by any conventionally known production method. For example, the disproportionate rosin is Pd, a carbon catalyst or the like. And a product produced by a saponification of the reaction product by reacting at 280 ° C., 10 kg / cm ² , for 4 hours in the presence of an oxidization catalyst. On the other hand, the terephthalic acid and isophthalic acid used as the acid component include terephthalic acid, isophthalic acid, and lower alkyl esters thereof. Examples of lower alkyl esters of terephthalic acid and isophthalic acid include, for example, dimethyl terephthalate, dimethyl isophthalate, diethyl terephthalate, diethyl isophthalate, dibutyl terephthalate, dibutyl isophthalate, etc., in terms of cost and handling. Dimethyl terephthalate and dimethyl isophthalate are preferred. These dicarboxylic acids or lower alkyl esters thereof may be used alone or in combination of two or more. The molar ratio of disproportionated rosin (1) to terephthalic acid and / or isophthalic acid (2) is preferably (1) / (2) = 0.2 to 0.6. When the molar ratio of the disproportionated rosin (1) to terephthalic acid and / or isophthalic acid (2) is lower than 0.2, the fixability tends to be poor and fog tends to occur. If it exceeds .6, the offset resistance tends to deteriorate and the image density tends to decrease.

  Moreover, in this invention, dicarboxylic acid other than these can be used with a terephthalic acid and isophthalic acid in the range which does not inhibit the objective of this invention. These other dicarboxylic acids include benzene dicarboxylic acids such as phthalic acid and phthalic anhydride; alkyl dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid; succinic acid substituted with an alkyl group having 16 to 18 carbon atoms. Acids; unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid, itaconic acid, glutaconic acid; cyclohexane dicarboxylic acid; naphthalenedicarboxylic acid; diphenoxyethane-2,6-dicarboxylic acid and lower monoesters of these acids; Examples include diesters and acid anhydrides. Since these dicarboxylic acids greatly affect the fixing property and blocking resistance of the toner, they are used in an appropriate amount in consideration of the required performance of the toner.

  In the present invention, examples of the glycidyl esters of tertiary fatty acids used as the alcohol component (b) include those represented by the following general formula (1).

(In the formula, R ¹ , R ² and R ³ represent an alkyl group.)
In the above formula, the carbon number of R ¹ , R ² and R ³ and the total number of carbon atoms of these groups are not particularly limited, but neodecanoic acid glycidyl ester having a total carbon number of R ¹ + R ² + R ³ is preferably 8. .

  In addition, rosin glycidyl ester may be used together with glycidyl ester of tertiary fatty acid. Examples of the aliphatic diol having 2 to 10 carbon atoms include, for example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4 -Butanediol, 2,3-butanediol, 1,4-butenediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 2-ethyl-2-methylpropane-1 , 3-diol, 2-butyl-2-ethylpropane-1,3-diol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2 , 4-Dimethyl-1,5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,7-heptanediol, 1,8-octane Diol, 1,9-nonanediol, 1,10-decanediol, 3-hydroxy-2,2-dimethylpropyl-3-hydroxy-2,2-dimethylpropanoate, diethylene glycol, triethylene glycol, dipropylene glycol, etc. Is mentioned. As the aliphatic diol, neopentyl glycol is preferable from the viewpoint of reactivity with acid and glass transition temperature of the resin.

  These aliphatic diols may be used alone or in combination of two or more. Moreover, it is preferable that the molar ratio of the glycidyl ester (3) of tertiary fatty acid and the aliphatic diol (4) having 2 to 10 carbon atoms is (3) / (4) = 0.05 to 0.4. When the molar ratio of tertiary fatty acid glycidyl ester (3) and aliphatic diol (4) having 2 to 10 carbon atoms is lower than 0.05, fog is likely to occur, and when the molar ratio exceeds 0.4, Tends to deteriorate the offset resistance and blocking resistance. By using rosin glycidyl ester together with glycidyl ester of tertiary fatty acid, offset resistance and blocking resistance are improved. The rosin glycidyl ester is preferably used in an amount of 2 to 50 mol% in the component (b), and the glycidyl ester of a tertiary fatty acid is preferably used in an amount of 5 to 30 mol% in the component (b). The molar ratio (2) / (4) of the aliphatic diol of the alcohol component (4) to the dicarboxylic acid of the component (2) of the acid component is the molar ratio (1) of the acid components (1) and (2). Although it varies depending on the value of / (2) and the molar ratio (3) / (4) of the alcohol components (3) and (4), it is usually preferably 0.8 to 2.0.

  Examples of the trivalent or higher polycarboxylic acid used as the crosslinking component (c) in the present invention include trimellitic acid, pyromellitic acid, 1,2,4-cyclohexanetricarboxylic acid, naphthalenetricarboxylic acid, butanetricarboxylic acid, Examples include hexanetricarboxylic acid, tetra (methylenecarboxyl) methane, octanetetracarboxylic acid, benzophenonetetracarboxylic acid, and anhydrides thereof. These may be used alone or in combination of two or more. Trivalent or higher polycarboxylic acid is preferably trimellitic anhydride from the viewpoint of reactivity. Examples of the trivalent or higher polyols include polyhydric alcohols such as glycerol, diglycerol, sorbitol, sorbitan, butanetriol, trimethylolethane, trimethylolpropane, and pentaerythritol. These may be used alone or in combination of two or more. As the trivalent or higher polyol, pentaerythritol, trimethylolpropane and the like are preferable.

  These crosslinking components have the effect of increasing the non-offset property by crosslinking or branching the linear polyester resin, and the content thereof is the ratio of component (1) / (2) in the acid component (a) or alcohol component (b). Depending on the ratio of component (3) / (4), the ratio of use of acid component (a) and alcohol component (b) or the ratio of use of acid component (2) and alcohol component (4), Whether the crosslinking component is an acid or an alcohol depends on the number of functional groups of the acid or alcohol. For example, when tricarboxylic acid is used as the crosslinking component, it is usually used in an amount of 5 to 35 mol%, preferably 10 to 30 mol%, based on the total acid component. A toner using a polyester resin in which the amount used exceeds 35 mol% has a high number average molecular weight and tends to have poor fixability.

  In the present invention, the polyester resin for toner is reacted and synthesized in a reaction vessel having the predetermined acid component, alcohol component and crosslinking component as raw materials and having a discharge port at the bottom of a reaction vessel or the like. The reaction method may be either a transesterification reaction or a direct esterification reaction. In addition, polycondensation can be promoted by a method of increasing the reaction temperature by pressurization, a pressure reduction method, or a method of flowing an inert gas under normal pressure. In the above reaction, a known and commonly used reaction catalyst such as at least one metal compound selected from antimony, titanium, tin, zinc and manganese may be used to accelerate the reaction. Specific examples of the reaction catalyst include di-n-butyltin oxide, stannous oxalate, antimony trioxide, titanium tetrabutoxide, manganese acetate, and zinc acetate. The addition amount of these reaction catalysts is usually preferably about 0.001 to 0.5 mol% with respect to the acid component in the obtained polyester resin.

  In the synthesis of the polyester resin for toner of the present invention, a direct esterification method at normal pressure is mentioned as a preferred method during the above various reactions. In this direct esterification method, for example, all of the alcohol component is charged into the reaction vessel at the start of the reaction, and the acid component is charged after the temperature is raised to about 160 ° C. Di-n-butyltin oxide, stannous oxalate, antimony trioxide and the like are used as the reaction catalyst, and an addition amount of 0.01 to 0.1 mol% is appropriate with respect to the total acid components. In this case, a sufficient reaction rate can be obtained even at normal pressure, but the reaction temperature can be increased by applying a pressurizing operation. The promotion of the reaction by depressurization operation is applied in the case where almost no unreacted alcohol is consumed at the end of the reaction, and the removal of the generated water is delayed. The promotion of the reaction by passing through an inert gas can be applied to any process of the reaction in such an amount that it minimizes the dissipation of alcohol out of the system. In addition, the reaction is usually terminated by confirming the softening point of the resin, the amount of produced water, or the viscosity of the reaction product, and cooling the temperature of the reaction product to 100 ° C. or lower. When the polyester resin is discharged from the reaction vessel, the amount of discharge is large on an industrial scale, and it takes a considerable time from the start to the end of the extraction. Further, during the resin discharge, it is necessary to keep the temperature of the resin in the reaction vessel at a certain temperature or higher in order to maintain the viscosity at which the resin can be discharged. As a result, a difference occurs in the physical properties of the resin at the start of discharge and at the end of discharge, and it is difficult to obtain a polyester resin having desired physical properties.

  Further, when a non-linear polyester resin is synthesized without using a bisphenol A derivative as a synthetic monomer raw material, such as the polyester resin for toner of the present invention, gelation of the resin tends to proceed, and particularly for the toner of the present invention. When a non-linear polyester resin is synthesized from the monomer composition of the polyester resin, the gelation proceeds rapidly. For this reason, in the production of the polyester resin for toner of the present invention, it is necessary to quickly discharge and take out the resin from the reaction vessel, and further eliminate variations in lots of the quality of the obtained resin. In order to stabilize the quality of the obtained resin, it is also necessary to correct the history of discharging and taking out the resin.

  In the present invention, when the synthesis reaction of the polyester resin for toner is finished and the resin is taken out from the reaction vessel and commercialized, the temperature of the polyester resin in the synthesized reaction vessel is maintained at 160 to 250 ° C. The viscosity is 3 to 400 Pa · s, and the viscosity at the end of discharge is 50 to 500 Pa · s, taken out from the reaction vessel outlet, and after passing through the cooling step and the pulverizing step, the entire amount of the pulverized resin is mixed using a mixer. By mixing and homogenizing the product resin, a polyester resin for toner having desired physical properties can be obtained.

In the production of the polyester resin of the present invention, by taking out the resin from the reaction vessel under these discharge conditions and producing the polyester resin for toner, there is no production variation within the lot and between lots, and mass production of a stable quality resin is achieved. It becomes possible. As is apparent from the above production conditions, in the production of the polyester resin for toner of the present invention, the following points are important points for eliminating the manufacturing variation and making the resin quality uniform.
(A) Temperature, viscosity (at the start and end of discharge), and further, if necessary, specify conditions such as discharge speed and time, take out from the reaction vessel, discharge, and resin at the start of discharge and at the time of final discharge Make the quality of the resin as uniform as possible. In order to make the quality uniform, it is preferable to discharge quickly, and for this purpose, for example, it is effective to pressurize the inside of the reaction vessel or to install a pump in the discharge portion and suck it. In particular, pressurization with an inert gas is preferable in blocking oxygen and suppressing the acid value of the resin.
(B) After discharging, the resin temperature was 10 J / g · min. Further reaction of the polyester resin is stopped by cooling to 100 ° C. or lower at the above cooling rate.
(C) After the pulverization step, the obtained resin pulverized product is mixed and homogenized by a mixer. As a result, the difference between the resin discharged at the initial stage and the resin discharged at the end is homogenized by mixing, and the variation in the quality of the resin in the lot is corrected.

Hereinafter, the method for discharging the resin of the present invention will be described more specifically.
In the discharging step, the temperature of the synthesized polyester resin needs to be maintained at 160 to 250 ° C. If the temperature is lower than 160 ° C., the viscosity of the resin increases and it becomes difficult to discharge. In addition, as the viscosity increases, it takes time to discharge, and as a result, the gelation of the resin in the reaction vessel proceeds and there is a risk that the THF-insoluble content exceeds 50%. On the other hand, since the viscosity of the resin in the container decreases as the temperature of the resin increases, the discharge rate at the time of discharge increases, but if the resin temperature becomes higher than 250 ° C., By removing the contained water, further condensation polymerization of the polyester resin easily proceeds, gelation proceeds and the molecular weight increases, resulting in a higher viscosity at the end of discharge and a higher proportion of THF insoluble matter. In addition, it takes time for complete discharge. Furthermore, even if it has a desired acid value and hydroxyl value in the reaction vessel, if it is 250 ° C. or higher at the time of discharge, the remaining —COOH group and —OH group will further react, resulting in an acid value and hydroxyl value. It becomes impossible to control the numerical value of.

  On the other hand, although the viscosity of the resin is closely related to the temperature of the resin, the viscosity of the resin at the start of discharging may be 3 to 400 Pa · s, and the viscosity of the resin at the end of discharging may be 50 to 500 Pa · s. Needed. Thereby, the polyester resin can be discharged in a state in which the quality of the polyester resin is favorably maintained. For example, when obtaining a polyester resin for toner having desired characteristics, it is usually necessary to set the resin temperature to a temperature exceeding 250 ° C. in order to make the viscosity of the resin at the start of discharging smaller than 3 Pa · s. When the resin temperature exceeds 250 ° C., gelation is likely to proceed as described above, the gelation rate increases at the end of discharge, and the THF-insoluble matter becomes 50% or more, resulting in a binder resin for toner. Can no longer be used. This is because if the resin viscosity is usually less than 3 Pa · s at a temperature of 250 ° C. or lower, sufficient reaction has not yet progressed. Further, if the value is larger than the range of 400 Pa · s from the start of discharge, the polyester resin in the reaction vessel cannot be discharged in general due to the progress of the reaction during discharge, and production cannot be performed. It will be.

  Further, if the viscosity of the resin at the end of the discharge is less than 50 Pa · s, the molecular weight to be gelled is not obtained, and the resulting polyester resin has a low gelation rate, which is desirable as a finally obtained polyester resin. The gelation rate (THF insoluble matter) cannot be obtained, and it cannot be used as a binder resin for toner. Moreover, if the value is larger than the range of 500 Pa · S, the THF insoluble content of the obtained resin becomes larger than 50%. Or, even if it can be discharged, it will be affected by the heat of the reaction kettle at the time of discharging, and the gelation will progress further, increasing the difference in gelation rate at the start of discharging and at the end of discharging, and making it uniform in the subsequent process Even if it is performed, the resin cannot be sufficiently homogenized, the quality is unevenly distributed, and becomes unstable.

  Thus, the viscosity of the polyester resin when discharged must be in the range of 3 to 500 Pa · s as a whole. In addition, even when the homogenization of the resin is taken into consideration, the difference between the viscosity of the resin at the start of discharging and the viscosity of the resin at the end of discharging is preferably within 400 Pa · s, which is preferable in terms of stabilizing the quality of the resin. More preferably, it is within 300 Pa · s, and within this range, the resin can be produced with very stable quality.

By filling and discharging both the viscosity of the resin at the start of discharge and the viscosity of the resin at the end of discharge, the synthesized polyester resin can be discharged while maintaining a good state. is there. Moreover, by satisfying these viscosity ranges, the synthesized polyester resin can flow and can be easily homogenized, and a polyester resin with favorable quality can be stably produced even in mass production. Is. By discharging in this range, the gelation rate of the obtained polyester resin can be obtained within a preferable numerical range. That is, it is expressed as tetrahydrofuran (THF) insoluble matter, and can be 1 to 50% by weight, more preferably 3 to 30% by weight or less.
Further, in the state of the resin at the start of discharge, it is preferable that the molecular weight is small and gelation does not proceed, and the desired gelation rate and THF-insoluble content are satisfied after the entire resin is taken out and homogenized.

  The viscosity may be measured with, for example, an in-line viscometer provided in the reaction vessel. In this case, a plurality of viscometers can be installed in the reaction vessel as necessary. When a plurality of viscometers are installed in the reaction vessel, the viscosity of the resin at the start of discharge depends on the viscosity indicated by the viscometer closest to the discharge port of the reaction vessel. Moreover, since the viscosity at the end of the discharge is the resin viscosity measured last by the viscometer closest to the discharge port in the container, it is preferable to install one of the viscometers in the vicinity of the reaction container discharge port.

  In the present invention, as a method of discharging the synthesized resin from the reaction vessel, a method of naturally discharging by its own weight from the discharge port, a method of pressing and discharging the inside of the reaction vessel, and further using an inert gas in the reaction vessel A method of pressurizing, and a method of forcibly suctioning by attaching a gear pump or the like to the discharge part are also included. In the present invention, as long as the above discharge conditions are satisfied, any of the above methods may be adopted, but the quicker the discharge, the smaller the difference in resin physical properties at the start and end of discharge, that is, Since a homogeneous resin can be obtained, a method in which an inert gas is injected into a reaction vessel and the polyester resin in the vessel is discharged while being pressurized by the pressure is a preferred method. The use of the inert gas here is important not only for pressurization for discharging, but also for preventing oxidation of rosin (disproportionated rosin, rosin glycidyl ester) derived from monomers in the polyester resin. Rosin is easily oxidized and discolored when exposed to high temperatures in air, and cannot be used as a binder for color toners. Moreover, the structural formula of the disproportionated rosin component is changed by oxidation. As a result, the composition and characteristics of the synthesized polyester resin change, which has a problem of affecting the charge amount, resistance, and the like of the toner. Therefore, it is important that the resin is not affected by oxygen as much as possible when the resin is discharged. For this reason, if necessary, the step of cooling the discharged resin may be performed in an inert gas atmosphere. Examples of the inert gas include inert gases such as nitrogen gas, helium gas, and argon gas. Among these, nitrogen gas is preferably used from the viewpoint of cost and versatility. It is also a preferred technique to pressurize the inside of the reaction vessel with an inert gas, and at the same time attach a gear pump to the discharge part and perform discharge.

The flow rate of the synthesized polyester resin at the time of discharge determines the range of the viscosity of the polyester resin and greatly affects the quality. For example, when the volume of the reaction vessel is 1.5 m ³ and the area of the opening used for discharging is 177 cm ² , the pressure condition when discharging using inert gas is the outflow rate of the discharged resin 0.10 kg / min. It is preferable to pressurize so that it may become cm ² or more. 0.10 kg / min. If the speed is at least cm ² , the quality of the synthesized polyester resin can be maintained, and the polyester resin can be taken out without impairing the quality. The outflow rate is 0.10 kg / min. When it is slower than cm ² , although depending on various conditions (temperature, viscosity, resin composition), the polyester resin may gelate during discharge, which may make it difficult to discharge. Here, the faster the outflow speed is, the more preferable characteristics are. It is best that the outflow speed can be taken out instantaneously, and the upper limit speed is not specified.

  In the present invention, the amount of raw material charged into the reaction vessel is 500 kg per batch for small batch production, generally about 1000 kg or more, and 10 t for mass production on a larger industrial scale. To the extent that it is usually considered. As a reaction vessel to be used, it is preferable to use one having a volume of at least 1.5 times the charged amount. This is because the monomer is refluxed during the synthesis of the polyester resin. Further, in the production of the polyester resin for toner of the present invention, as a device attached to the reaction vessel, a raw material supply device, a supply port, a stirring device, a heating device, a thermometer, a viscometer, a pressurization, a decompression device, an inert gas An introduction pipe, a partial condenser for removing condensed water, a total condenser, a receiver tank for collecting condensed water, a filter or a gear pump in the discharge section, and the like are used. Further, in the reaction process, it is possible to produce in one reaction kettle, but it is also possible to produce in two stages using two reaction kettles in consideration of the material to be added.

  The polyester resin discharged and taken out is subjected to a cooling step and a pulverizing step, and then mixed and homogenized by a mixer to obtain a good polyester resin for toner. In the cooling process, the resin may be cooled using various conventionally known cooling devices such as a steel belt cooler, a drum cooler, a roll cooler, an air cooling belt, a strand cooler, a water-cooled bat-type cooling device, and a rolling roll. . In this cooling step, it is preferable to cool the discharged polyester resin to 100 ° C. or less as quickly as possible. By cooling to 100 ° C. or lower, the further reaction of the polyester resin can be completely stopped. In addition, when bat-type cooling by water cooling is performed, moisture must be removed using a dryer in order to remove moisture in the resin. In such a case, the bat is generally dried using a catered dryer.

  About this cooling condition, it is preferable that it is a cooling rate of 10 J / g * min. Or more. The specific heat of the polyester resin is 2.2 J / g · ° C. (220 ° C.), 2.0 J / g · ° C. (140 ° C.), and 1.9 J / g · ° C. (100 ° C.). If the heat is dissipated at a cooling rate of 10 J / g · min. Or more, the change with time of the resin can be suppressed, and a resin satisfying desired physical properties can be obtained. On the other hand, when the cooling rate is lower than 10 J / g · min., The gelation of the polyester resin proceeds during cooling, the low molecular weight of the resin decreases, and the resistance of the resin increases, resulting in a toner. This causes problems such as poor fixing and deterioration of image characteristics. Further, the thickness of the polyester resin at the time of cooling is preferably 10 mm or less in consideration of the subsequent pulverization. In the pulverization step, the particle size is crushed to a maximum particle size of 10 mm or less, more preferably 3 mm or less using a conventionally known crusher such as a sample mill, a pin rotor, a pin mill, a roll mill, a hammer mill, or a cutter mill. And fine pulverization using an impact pulverizer such as ACM. In consideration of the toner production process, the polyester resin is preferably pulverized to a maximum particle size of 3 mm or less.

  When the polyester resin is discharged from the reaction vessel and taken out, the state at the start of discharge and the state at the end of discharge are different in the progress of the reaction in the reaction vessel due to the time difference in discharge. The gel content and the like are different, and if it is used as it is, it can be considered that quality variation occurs in the production batch. For this reason, it is preferable that the entire amount of the polyester resin in the reaction vessel is discharged, cooled and pulverized, and then uniformly mixed and homogenized using a mixer. Any mixer can be used as long as it is a known mixer, and specific examples include a Nauter mixer, a Henschel mixer, and a super mixer. Among them, it is preferable to use a conical screw mixer such as a Nauter mixer. After passing through the cooling and pulverizing processes, the polyester resin for toner of the present invention can be obtained by adding the entire amount of polyester resin to a mixer and homogenizing it.

  In the present invention, a polyester resin for toner is obtained through the above steps. The softening temperature of the obtained polyester resin is 115 to 150 ° C., preferably 120 to 145 ° C. When the softening temperature is less than 115 ° C., the cohesive strength of the resin is extremely reduced. On the other hand, when it exceeds 150 ° C., the melt flow and low-temperature fixability of the toner using the resin are reduced. This is because is no longer suitable.

  The acid value of the polyester resin for toner produced according to the present invention is in a preferred range depending on whether the polyester resin for toner obtained according to the present invention is used as a binder resin for negatively charged toner or as a binder resin for positively charged toner. Is different. When used as a binder resin for negatively charged toner, it is desirable that the acid value is 10 to 60 mgKOH / g, preferably 15 to 55 mgKOH / g, and the hydroxyl value is 20 mgKOH / g or less, preferably 15 mgKOH / g or less. When the acid value is less than 10 mgKOH / g, the negative chargeability of the toner is reduced, and the image density is lowered. On the other hand, when the acid value is more than 60 mgKOH / g, the negative chargeability of the toner is decreased particularly in a low humidity environment. The image density is lowered particularly in a high-humidity environment because the image becomes too large to cause fogging and the hydrophilicity is increased. Further, when the hydroxyl value exceeds 20 mgKOH / g, the hydrophilicity increases, so that the image density decreases particularly in a high humidity environment. When used as a binder resin for a positively charged toner, it is desirable that the acid value is 20 mgKOH / g or less, preferably 10 mgKOH / g or less, and the hydroxyl value is 20 mgKOH / g or less, preferably 15 mgKOH / g or less. When the acid value is 20 mgKOH / g or more, the positive chargeability of the toner is reduced and the image density is lowered. Further, when the hydroxyl value exceeds 20 mgKOH / g, the hydrophilicity increases, so that the image density decreases particularly in a high humidity environment.

The number average molecular weight of the tetrahydrofuran (THF) soluble part of the polyester resin for toner produced in the present invention is 1,000 to 6,000, preferably 2,000 to 4,000. When the number average molecular weight of the polyester resin is small, the offset resistance of the toner tends to be reduced, whereas when the number average molecular weight is large, the fixability tends to be lowered. The polyester resin is of a type having a molecular weight distribution curve of two peaks composed of a specific low molecular weight condensation polymer component and a specific high molecular weight condensation polymer component, or a type having a single molecular weight distribution curve. Any one may be used. From the viewpoint of preventing toner aggregation, the obtained polyester resin for toner has a glass transition temperature (Tg) measured by a differential scanning calorimeter (DSC) of 45 to 70 ° C, preferably 50 to 65 ° C. Some are desirable. Furthermore, the true density of the resin is preferably 1.1 to 1.3 g / cm ³ . When the true density of the resin is low, the toner can be used in a small amount when an image having the same density is formed, and as a result, economical copying can be performed. On the other hand, if the true density is higher than 1.3 g / cm ³ , the amount of toner used increases.

The THF-insoluble content of the polyester resin obtained by the production method of the present invention is preferably 1 to 50% by weight, and more preferably 3 to 30% by weight. By satisfying this range, a good image can be obtained when used as a toner. To control the THF-insoluble content of the polyester resin of the present invention (1) Type and amount of crosslinking component (2) Crosslinking reaction temperature (3) Crosslinking reaction time until crosslinking is stopped (including cooling time) (4) Removal temperature from the reaction vessel (5) Removal viscosity from the reaction vessel (6) Removal rate from the reaction vessel is an important factor. In order to adjust the THF-insoluble content to 1 to 50% by weight, more preferably 3 to 30% by weight, the addition amount of the crosslinking component (1) is, for example, when tricarboxylic acid or triol is used as the crosslinking component, 5-35 mol% is preferable with respect to a component, The temperature of the crosslinking reaction of (2) is preferably 160-250 degreeC, The time of the crosslinking reaction of (3) is preferable 3-15 hours, The taking-out temperature of (4) is It is preferable to maintain the temperature of the polyester resin at 160 to 250 ° C. The viscosity at the time of taking out (5) is preferably in the range of 3 to 400 Pa · s at the start of discharging and 50 to 500 Pa · s at the end of discharging, and further, the taking out speed of (6). Is 0.10 kg / min. As the amount of resin passing per unit area per minute. It is preferable that it is cm ² or more. These six items may be set together with the conditions of the acid component and the alcohol component so that desired resin properties (acid value, hydroxyl value, etc.) can be obtained. If it is produced outside these ranges, the THF-insoluble content of the resin may not satisfy 1 to 50% by weight. When the THF-insoluble content exceeds 50% by weight, the toner fixability is deteriorated or the resistance of the resin is increased, resulting in image defects due to toner charge-up. Further, if the THF-insoluble content is less than 1% by weight, the fixing is hindered, and particularly hot offset occurs.

  When an electrostatic charge image developing toner is obtained using the polyester resin obtained by the production method of the present invention, a positive or negative charge control agent is used depending on the polarity of the electrostatic latent image to be developed. Added and contained. Representative examples of charge control agents include those that impart a positive charge to the toner, such as basic dyes such as nigrosine dyes and triarylmethane dyes, quaternary ammonium salts, organic tin oxides, and amino groups. As an electron donating substance such as a polymer having a negative charge to a toner, for example, metal complexes of monoazo dyes, metal-containing dyes such as chromium-containing organic dyes (copper phthalocyanine green, chromium-containing monoazo dyes), salicylic acid, etc. Examples include metal complexes and metal salts of aryloxycarboxylic acids.

  When an electrostatic charge image developing toner is obtained using the polyester resin obtained by the production method of the present invention, any colorant known to be used in the production of conventional toners can be used as the colorant. Examples of these colorants include black colorants such as carbon black and iron black, and colorants such as phthalocyanine, rhodamine, quinacridone, triarylmethane, anthraquinone, and azo. , Diazo-type, methine-type, allylamide-type, thioindigo-type, naphthol-type, isoindolinone-type, diketopyrrolopyrrole-type, benzimidazolone-type dyes, their metal complex compounds, lake compounds, etc. .

  When an electrostatic charge image developing toner is obtained using the polyester resin obtained by the production method of the present invention, a wax as a release agent may be contained in an amount of 0.5 to 10% by weight based on 100 parts by weight of the resin. it can. Examples of such a wax include fatty acid esters such as polypropylene wax, polyethylene wax, paraffin wax, fatty acid amide wax, carnauba wax, and montan wax, partially saponified fatty acid ester wax, and fatty acid metal salts.

  Further, when an electrostatic charge image developing toner is obtained using the polyester resin obtained by the production method of the present invention, a magnetic powder may be added as necessary to obtain a magnetic toner. As the magnetic powder internally added to these toners, any powders of alloys, oxides, compounds and the like containing ferromagnetic elements that are conventionally used in the production of magnetic toners can be used. Examples of these magnetic powders include magnetic iron oxides such as magnetite, maghemite, and ferrite, or compounds of divalent metals and iron oxides, metals such as iron, cobalt, and nickel, or aluminums of these metals, cobalt, copper, Examples include powders of alloys of metals such as lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium, and mixtures of these powders. These magnetic powders preferably have an average particle size of 0.05 to 2.0 μm. Further, the content of the magnetic powder in the toner is about 5 to 200 parts by weight with respect to 100 parts by weight of the thermoplastic resin. Further, the saturation magnetization of the toner is preferably 15 to 35 emu / g (measuring magnetic field: 1 kilo-Oersted). The magnetic powder also functions as a colorant. When the magnetic powder is used, other colorants need not be used, but if necessary, together with carbon black, copper phthalocyanine, etc. It may be used.

  When a toner for developing an electrostatic charge image is obtained using the polyester resin obtained by the production method of the present invention, a lubricant, a fluidity improver, an abrasive, a conductivity-imparting agent, an image peeling prevention agent, etc. A known additive used in the production of toner can be added internally or externally. Examples of these additives include polyvinylidene fluoride and zinc stearate as lubricants, and silica, aluminum oxide, titanium oxide produced by a dry method or a wet method as a fluidity improver, and hydrophobic these. Abrasives such as silicon nitride, cerium oxide, silicon carbide, strontium titanate, tungsten carbide, calcium carbonate, and those hydrophobized, such as carbon black, oxidized Examples include tin.

  The electrostatic image developing toner obtained by using the polyester resin obtained by the production method of the present invention preferably contains fine powders such as hydrophobized silica, titanium oxide, and alumina as external additives. Examples of the hydrophobic treatment of these fine powders include treatment with a silane coupling agent such as silicone oil, tetramethyldisilazane, dimethyldichlorosilane, and dimethyldimethoxysilane. The amount of hydrophobized fine powder such as silica that has been hydrophobized is 0.01 to 20% based on the weight of the developer.

  The weight average particle diameter of the toner particles in the toner for developing an electrostatic charge image obtained using the polyester resin obtained by the production method of the present invention is preferably 3 to 15 μm. The toner particle size distribution can be measured using, for example, a Coulter counter.

  The toner particles constituting the toner for developing an electrostatic charge image obtained using the polyester resin obtained by the production method of the present invention can be produced by a conventionally known method for producing toner particles. In general, the polyester resin, charge control agent, colorant, etc., which are the constituent materials of the toner particles as described above, are sufficiently premixed by a mixer such as a Henschel mixer, and then heated rolls, kneaders, extruders, etc. A preferable method is to knead well using a thermal kneader, cool and solidify, mechanically pulverize using a pulverizer such as a hammer mill, then finely pulverize using a jet mill or the like, and then classify. The classified toner is mixed with an external additive as necessary using a mixer such as a Henschel mixer to obtain a toner.

  The electrostatic image developing toner obtained using the polyester resin obtained by the production method of the present invention can be mixed with a carrier and used as a two-component developer. Examples of the carrier include magnetic powder such as iron powder and ferrite powder. These carrier particles may have a surface coated with a resin as necessary. Examples of the resin for coating the carrier surface include styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, acrylic acid ester copolymer, methacrylic acid ester copolymer, fluorine-containing resin, and silicone-containing resin. Is mentioned.

The electrostatic charge image developing toner using the polyester resin obtained by the production method of the present invention does not use bisphenol A derivatives such as bisphenol A or an ethylene oxide adduct of bisphenol A as the alcohol component of the polyester resin. It is preferable from the viewpoint of hormones, and an environmentally friendly toner can be obtained.
Further, according to the polyester resin for toner obtained by the production method of the present invention, even without using bisphenol A or a derivative of bisphenol A, offset resistance, low-temperature fixability, sharp melt resistance, A toner having properties such as blocking properties, charging properties, grindability, and transparency can be obtained. Further, since bisphenol A or a derivative thereof is not used in the polyester resin of the present invention, the polyester resin for toner can be produced at a low cost. Moreover, the polyester resin for toner of the present invention has bisphenol A or its alcohol component as an alcohol component. Since the true density of the resin is smaller than that using a derivative, development with a toner prepared using the resin can reduce the amount of toner used per sheet and lower the copying cost.
In addition, according to the method for producing a polyester resin for toner of the present invention, the polyester resin for toner having the above excellent characteristics can be industrially mass-produced and supplied.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further more concretely, this invention is not limited at all by these Examples and a comparative example.

  In the following examples and comparative examples, the acid value, hydroxyl value, glass transition temperature (Tg), softening point and true density of the resin will be described first.

(Acid value and hydroxyl value)
The acid value refers to the number of milligrams of potassium hydroxide necessary to neutralize the acid groups contained in 1 g of a sample. The hydroxyl value refers to the number of milligrams of potassium hydroxide necessary to neutralize acetic acid bonded to a hydroxyl group when 1 g of a sample is acetylated.

(Glass-transition temperature)
The glass transition temperature is measured by using a differential scanning calorimeter (DSC-50, manufactured by Shimadzu Corporation) with an extension of the baseline below Tg when measured at a heating rate of 20 ° C./min, and an endothermic curve near Tg. The temperature at the intersection of tangents.

(Softening point)
The softening point was measured using an elevated flow tester (CFT-500D, manufactured by Shimadzu Corporation) with a load of 30 kg, a nozzle diameter of 1 mm, a nozzle length of 10 mm, a preheating temperature of 80 ° C. for 5 minutes, and a heating rate of 3 The temperature at the time of h / 2 when the height of the S-shaped curve in the plunger descent amount-temperature curve of the flow tester is h, when measured as ° C / min and the sample amount is 1 g.

(True density)
The true density refers to a value measured by a vapor phase substitution method using a dry automatic densimeter (Shimadzu-Micromeritics Accupic 1330 (10 cm ³ )). The measurement conditions are as follows.
Measurement gas: Helium Introduced pressure: Purge and run 19.5 psig (134.35 Kpag)
Equilibrium judgment pressure: 0.0050 psig / min (0.0345 Kpag / min)
Temperature and humidity: 23 ° C / 50% RH

(viscosity)
The viscosity was measured using an ICI viscometer.

Example 1
As raw material alcohol components of polyester resin, neopentyl glycol 100 mol%, neodecanoic acid glycidyl ester 13 mol%, disproportionated rosin 23 mol% as raw acid components, stirrer, heating device, thermometer, fractionator, nitrogen Charged into a stainless steel reaction vessel (with an internal volume of 1.5 m ³ ) equipped with a gas inlet tube and an outlet at the bottom, replaced with nitrogen gas, heated to 160 ° C. with stirring, and the contents melted I let you. After melting, condensed water produced by charging 77 mol% terephthalic acid and 0.03 mol% di-n-butyltin oxide as raw acid components so that the temperature at the top of the fractionator does not exceed 100 ° C. Was removed from the system with a nitrogen gas stream, the temperature was gradually raised to 240 ° C., and the esterification reaction was carried out over 15 hours. When the acid value reached 15 mgKOH / g, the mixture was cooled to 200 ° C. After cooling, 25 mol% of trimellitic anhydride was charged, and then the esterification reaction was performed over 9 hours by gradually raising the temperature to 240 ° C. while removing condensed water outside the system by the same operation as described above. The reaction was terminated after confirming that a predetermined softening point had been reached by a flow tester.
After completion of the reaction, the resin temperature in the reaction vessel was kept at 210 ° C., and a total amount of 1000 kg of polyester resin was discharged while injecting nitrogen gas and pressurizing. At this time, the viscosity at the start of discharge is 10 Pa · s, the viscosity at the end of discharge is 200 Pa · s, the size of the outlet of the reaction vessel is 150 mm in diameter (area: about 177 cm ² ), and the outflow per unit area from the outlet The speed is 0.38 kg / min. cm ² . After discharging and taking out, the thickness of the resin is 7 mm with a rolling roll and a cooling belt, and the resin temperature is 34.1 J / g · min. The mixture was cooled to 55 ° C. under the condition of the cooling rate, and pulverized with a sample mill to obtain a polyester resin having a particle diameter of 3 mm. Further, the total amount of the obtained polyester resin was uniformly mixed with a Nauta mixer. The physical property values of the obtained polyester resin A1 are shown in Table 1.
The composition amount “mol%” of each monomer is mol% with respect to the total acid component.

Examples 2-11, Comparative Examples 1-5
Polyester in the same manner as in Example 1 except that the mixing ratio of the acid component, alcohol component, and crosslinking component is set to the mixing ratio shown in Tables 1 to 3 and that the discharge / removal conditions are the conditions shown in Tables 1 to 3. Resins A2 to A7, B, C, D, E (Examples 2 to 11) and A8 to A12 (Comparative Examples 1 to 5) were obtained. The physical property values of the obtained polyester resin are shown in Tables 1-3.

  In Comparative Examples 1 to 4 (polyester resins A8 to A11), the THF-insoluble content was 50% or more, which was a quality that cannot be used as a binder resin for toner as described later. In Comparative Example 5, the viscosity increased during the discharge and the gelation progressed, and the discharge could not be performed to the end. Further, as in Comparative Example 5, in the case where the pressurization with nitrogen gas in the container and the suction of the discharge part are not performed, not only the discharge condition of the desired viscosity cannot be obtained, but the resin is exposed to the air, The resin turned blackish brown due to oxidation of the rosin component.

Example 12
Polyester resin raw material alcohol component neopentyl glycol 70 mol%, neodecanoic acid glycidyl ester 8 mol%, disproportionate rosin 23 mol% as raw acid component, stirring device, heating device, thermometer, fractionator, nitrogen gas introduction A stainless steel reaction vessel (with an internal volume of 1.5 m ³ ) equipped with a tube and having an outlet at the bottom was charged with nitrogen gas, and the temperature was raised to 160 ° C. with stirring to melt the contents. . After melting, condensed water produced by charging 77 mol% terephthalic acid and 0.03 mol% di-n-butyltin oxide as raw acid components so that the temperature at the top of the fractionator does not exceed 100 ° C. Was removed from the system by a nitrogen gas stream, and the temperature was gradually raised to 240 ° C. to carry out an esterification reaction over 15 hours. When the acid value reached 30 mgKOH / g, the mixture was cooled to 160 ° C. After cooling, 8.5 mol% of pentaerythritol was charged, and then the esterification reaction was performed over 9 hours by gradually raising the temperature to 240 ° C. while removing condensed water out of the system by the same operation as described above. The reaction was terminated after confirming that a predetermined softening point had been reached by a flow tester.
After completion of the reaction, the resin temperature in the reaction vessel was kept at 210 ° C., and a total amount of 1000 kg of polyester resin was discharged while injecting nitrogen gas and pressurizing. At this time, the viscosity at the start of discharge is 8 Pa · s, the viscosity at the end of discharge is 230 Pa · s, the size of the outlet of the reaction vessel is 150 mm in diameter (area: about 177 cm ² ), and the outflow rate per unit area is 0.00. 30 kg / min. cm ² . After discharging and taking out, the thickness of the resin is 7 mm with a rolling roll and a cooling belt, and the resin temperature is 34.1 J / g · min. The mixture was cooled to 55 ° C. under the condition of the cooling rate, and pulverized with a sample mill to obtain a polyester resin having a particle diameter of 3 mm. Further, the total amount of the obtained polyester resin was uniformly mixed with a Nauta mixer. Table 3 shows the physical property values of the obtained polyester resin F.
The composition amount “mol%” of each monomer is mol% with respect to the total acid component.

Example 1
(Component) (Blending amount)
Polyester resin A1 100 parts by weight Magnetic substance (magnetite) 84 parts by weight Charge control agent (chromium salt compound of aromatic hydroxycarboxylic acid) 1.5 parts by weight Low molecular weight polypropylene 2.5 parts by weight After the above materials were uniformly mixed, By kneading, pulverizing, and classifying, negatively chargeable toner particles having an average particle diameter of 10.5 μm were obtained. Next, 0.25 parts by weight of silica fine powder treated with dimethyldichlorosilane, 1.0 part by weight of calcium carbonate fine powder treated with aminosilane, and 1.0 part by weight of silicon nitride fine particles are added to 100 parts by weight of the toner particles. To obtain a negatively chargeable magnetic toner.

The charge amount of the negatively chargeable magnetic toner was measured to evaluate the chargeability, and the storage stability was also evaluated. The results are shown in Table 4.
Further, using this negatively chargeable magnetic toner, a live-action test was conducted using a commercially available copying machine having a structure of a hot-pressing roll as a fixing device (iR6000 manufactured by Canon Inc.), and image density (initial and 10,000). Image density after sheet), fog (initial and 10,000 sheets fog value), consumption, fixing property, and offset resistance were evaluated. The results are shown in Table 4.

  Measurement and evaluation of charge amount, storage stability test and evaluation, image density measurement, fog density measurement, toner consumption measurement, fixing property test and evaluation, offset resistance test and evaluation are as follows: It was done like that.

(Measurement and evaluation of charge amount)
Cu—Zn ferrite carrier particles having an average particle size of 80 to 120 μm and a toner sample are weighed at a ratio of the toner concentration of 5% by weight with respect to the whole and mixed with a ball mill or the like, and then the toner is measured with a blow-off charge measuring device. The charge amount of was calculated. Specifically, the measurement was performed by the following method.
After weighing 19.0 g of Cu-Zn ferrite carrier core (trade name F-100) manufactured by Powder Tech Co., Ltd. and 1.0 g of the dried toner sample into a 50 cc plastic bottle and shaking 5 times, a ball mill (Shinei Koki Sangyo) (PLASTIC PLANT SKS type) was used, and mixing was performed for 30 minutes under the condition of the actual rotation value of 230 rotations (the poly bottle main body was 120 rotations).
The obtained sample after mixing was subjected to charge amount measurement using a blow-off charge amount measuring device manufactured by Toshiba Chemical Corporation. At this time, the blow pressure was 1 kgf / cm ² , the maximum value was read at a measurement time of 20 seconds, and the mesh was 400 mesh. The measurement environment was 23 ° C. and 50% RH.

(Storage stability test and evaluation)
40 g of toner is sealed in a 200 ml glass container, left in a constant temperature bath at 50 ° C. for 24 hours, and then observed by checking the toner blocking property. △ was assigned to those to be treated, and × was designated to be aggregates that were not easily loosened.

(Measurement of image density)
The image density was measured using a Macbeth photometer. The concentration may be 1.35 or more.

(Measurement of fog density)
This was done by measuring the reflectance with a photovolt. 1.5% or less is a good value.

(Measurement of toner consumption)
This is expressed as the number of tonergrams consumed per 1,000 sheets in an actual copy of a document with a blackening rate of 6%.

(Fixability test and evaluation)
The fixed image was rubbed with an eraser (dragonfly pencil MONO), and the value calculated by [image density after rubbing / image density before rubbing] × 100 was expressed as the fixing strength. 85% or more is a good value.

(Offset resistance test and evaluation)
After continuous copying of 200 images for fixing test, the sheet was stopped for 5 minutes, and then 20 blank sheets were passed through, and the evaluation was made based on the condition of the white paper. In the evaluation results, “O” indicates that no paper stain occurred, and “X” indicates that the paper stain occurred.

Use Examples 2-12, Comparative Use Examples 1-4
A toner is produced in the same manner as in Use Example 1 except that the polyester resin A1 is a polyester resin described in Table 4. The charge amount, storage stability, and image density of the produced toner (initial and 10,000) Evaluation of image density after image), fog (initial and 10,000 image fog values), consumption, fixing property, and offset resistance were performed in the same manner as in Example 1. The results are shown in Table 4.

Claims (7)

The acid component is (1) disproportionated rosin and (2) terephthalic acid and / or isophthalic acid, the alcohol component is (3) a glycidyl ester of a tertiary fatty acid and (4) an aliphatic diol having 2 to 10 carbon atoms, The crosslinking component is composed of a tricarboxylic or higher polycarboxylic acid and / or a trivalent or higher polyol, and the molar ratio (1) / (2) of the acid components (1) and (2) is 0.2 to 0.6. A polyester resin having a molar ratio (3) / (4) of the alcohol components (3) and (4) of 0.05 to 0.4 is synthesized in a reaction vessel having a discharge port at the bottom; Next, this synthesized polyester resin is discharged from the reaction vessel at a temperature of the polyester resin of 160 to 250 ° C., a viscosity at the start of discharge of 3 to 400 Pa · s, and a viscosity at the end of discharge of 50 to 500 Pa · s, The post-discharge Cooling the ester resin, after pulverizing method for producing a polyester resin for a toner, characterized by further mixing and homogenizing the ground product using a mixer. In the cooling step, the discharged polyester resin is 10 J / g · min. The method for producing a polyester resin for toner according to claim 1, wherein the polyester resin is cooled to 100 ° C. or less at the above cooling rate. 3. The method for producing a polyester resin for toner according to claim 1, wherein the inside of the reaction vessel is pressurized with an inert gas when discharged. The method for producing a polyester resin for toner according to any one of claims 1 to 3, wherein the pulverized polyester resin has an insoluble content in tetrahydrofuran (THF) of 1 to 50%. The method for producing a polyester resin for toner according to any one of claims 1 to 4, wherein the true density of the pulverized polyester resin is 1.1 to 1.3 g / cm ³ . 6. The method for producing a polyester resin for toner according to claim 1, further comprising rosin glycidyl ester as an alcohol component. The method for producing a polyester resin for toner according to any one of claims 1 to 6, wherein the difference between the viscosity of the resin at the start of discharging and the viscosity of the resin at the end of discharging is 400 Pa · s or less.