KR101155074B1 - Polyester resin for electrophotography toner, and toner produced using the same - Google Patents

Abstract

In an electrophotographic copying process or an electrostatic printing process, a polyester resin for producing an environmentally friendly toner having excellent low temperature fixability to an electrostatic lock material or a recording medium, excellent offset resistance and image density at a high temperature, and the same, Toner starts. The polyester resin for toner is prepared by esterification reaction and polycondensation reaction of a reactant including a branched aliphatic epoxy compound, aromatic dibasic acid and aliphatic diol. Here, the branched aliphatic epoxy compound may be erythritol, mannitol, sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, or water. Chloros, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, The polyhydric alcohol selected from the group consisting of trimethylolpropane and mixtures thereof is glycidylated to have 1 to 5 epoxy functional groups, and the content of the branched aliphatic epoxy compound and the aliphatic diol is respectively relative to the total alcohol component. It is 2-15 mol% and 55-98 mol%, and the content of the aromatic dibasic acid is 60-100 mol% with respect to the total acid component.

Electrostatic printing process, polyester, toner, aliphatic polyfunctional epoxy, fixability, environmentally friendly.

Description

Polyester resin for toner, and toner produced using the same}

The present invention relates to a polyester resin for a toner, and a toner manufactured by using the same, and more particularly, in an electrophotographic copying process or an electrostatic printing process, fixing property, storage stability, and image to an electrostatic recording material or a recording medium. The present invention relates to a polyester resin for toner having excellent concentration and environmentally friendly, and a toner produced using the same.

The electrophotographic copying process or electrostatic printing process comprises: (1) a statically charged image or an electronically conductive image (hereinafter referred to as an "electrostatic latent image") corresponding to an image to be recorded on the surface of the electrostatic recording material; latent image), (2) developing and visualizing the latent electrostatic image with charged toner, (3) transferring the developed toner image onto a recording medium such as paper, recording film, and (4) Fixing the transferred image onto the recording medium. Such an image-forming process is widely used in the field of copiers and printers because of the advantages that it is possible to obtain prints at a high speed, has excellent control stability of the images formed on the surface of the recording material, and facilitates operation of the image-forming apparatus. have. More specifically, the phase-forming process is an electrification process that causes charge on an organic photoconductor drum (OPC) coated with a photoconductive and photosensitive material, and an exposure to form an electrostatic latent image on the drum by the reflected light reflected from the original. Process, a developing process of electrostatically attaching the triboelectrically charged toner to the drum, a transfer process of charging the back side of the paper to adhere the paper to the drum and transferring the toner adhered to the drum to the paper, the transferred toner Is fixed to paper by heating and compressing with a thermocompression roller, a cleaning process for removing toner remaining on the drum, and an antistatic process for removing residual charge by shining light on the entire surface of the drum.

The toner used in the dry developing process of the developing process includes one-component toner, two-component toner, and the like. The two-component toner contains a binder resin, a colorant, a charge control agent and other additives, and a magnetic latent image formed on a magnetic drum. The toner for developing and transferring the film contains a magnetic material. Such toner is prepared in the form of particles by melting, kneading and dispersing the compound, finely pulverizing and classifying the compound. As the main component of the toner composition, the binder resin that dominates most of the toner properties is excellent in dispersibility, fixability, non-offsetability, storage stability, other electrical properties of the colorant during melting and kneading process, and excellent transparency. It is desirable to form a clear image without blurring with a little coloration, to have a wide range of color reproducibility, to have an excellent image density on a copy print, and to be environmentally friendly. As the binder resin, a polyester resin having excellent fixability, transparency, and the like has been attracting attention as a resin replacing a polystyrene resin, a styrene acrylic resin, an epoxy resin, a polyamide resin, and the like, which have been conventionally used. When obtaining the said polyester resin for toners, using bisphenol (A) or its derivative as an alcohol component is generally performed. However, recently, there is a debate that bisphenol (A) may affect the environment, and from the viewpoint of environmental protection, bisphenol (A) or its derivatives are not used from the market, and offset resistance and low temperature fixing are performed in the same manner as in the prior art. There is a demand for development of a polyester resin for a toner that is excellent in properties such as stiffness, sharp melt resistance, blocking resistance, charging characteristics, pulverization, and transparency, and which can form a good developing image over a long period of time. In addition, in recent years, the economics of toner are also important, and it is desired to provide an inexpensive toner binder resin. However, such a toner binder cannot necessarily meet such a requirement. In addition, as a catalyst used to prepare a polyester resin for a toner, a germanium catalyst, an antimony catalyst, a tin catalyst, and the like have been conventionally used. However, the catalyst activity is low, and thus an excessive amount is used, which is not environmentally friendly. (For example, the antimony-based catalyst has a problem that the transparency of the polyester resin is lowered due to the colorability of gray). Accordingly, as part or all of the catalyst, tetraethyl titanate, acetyltripropyl titanate, tetrapropyl titanate, tetrabutyl titanate, polybutyl titanate, ethyl acetoacetic ester titanate, isostearyl titanate, titanium Attempts have been made to improve the reactivity and transparency of resins using titanium-based catalysts such as dioxide, TiO ₂ / SiO ₂ co-precipitants and TiO ₂ / ZrO ₂ co-precipitators, which have less input than antimony-based catalysts, It has the advantage of excellent reactivity.

On the other hand, Korean Patent Laid-Open Publication Nos. 10-2005-0051543 and 10-2005-0006232 propose a binder polyester resin for a toner that does not use bisphenol (A) or its derivatives, and improves offset resistance of the toner. To this end, a method of strengthening the offset resistance of a resin through crosslinking or gelling (insoluble to tetrahydrofuran (THF) of a resin) by reacting a polyfunctional acid component with an alcohol component has been introduced. However, a crosslinked or gelled polyester resin has a high molecular weight and a softening point, a low temperature fixation characteristic, and a high speed fixing characteristic is not satisfactory. For example, when performing a copying operation at a rate of about 50 sheets / minute, the toner is poor in fixing characteristics and cannot obtain a copy having satisfactory toner fixing strength.

It is therefore an object of the present invention to provide a toner excellent in offset resistance and low temperature fixing property, and a polyester resin for producing the same.

Another object of the present invention is to provide an environmentally friendly toner and a polyester resin for producing the same, since bisphenol (A) or its derivatives and heavy metal compounds such as tin and antimony are not used as an alcohol component in polyester production.

In order to achieve the above object, there is provided a polyester resin for a toner prepared by esterification reaction and polycondensation reaction of a reactant comprising a branched aliphatic epoxy compound, aromatic dibasic acid and aliphatic diol. Here, the branched aliphatic epoxy compound may be erythritol, mannitol, sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, or water. Chloros, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, The polyhydric alcohol selected from the group consisting of trimethylolpropane and mixtures thereof is glycidylated to have 1 to 5 epoxy functional groups, and the content of the branched aliphatic epoxy compound and the aliphatic diol is respectively relative to the total alcohol component. It is 2-15 mol% and 55-98 mol%, and the content of the aromatic dibasic acid is 60-100 mol% with respect to the total acid component. In addition, the reactant further includes a compound selected from the group consisting of a titanium-based catalyst and an aliphatic dibasic acid, a polyacid, a monobasic acid, a polyhydric alcohol, and a monohydric alcohol, as necessary.

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

The reactant for producing the polyester resin for toner of the present invention includes a branched aliphatic epoxy compound. The branched aliphatic epoxy compound takes the structural formula of polyglycidyl ether form of a branched aliphatic polyhydric alcohol. For example, erythritol, mannitol, sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1 , 2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, etc. Polyhydric alcohol of the glycidyl (glycidyl) is a form having 1 to 5 epoxy functional groups. The content of the branched aliphatic epoxy compound is 2 to 15 mol%, preferably 5 to 10 mol% with respect to the total alcohol component. When the content of the aliphatic epoxy compound exceeds 15 mol%, it is difficult to control the gelation of the polyester resin during the manufacture of the polyester resin, so that it is difficult to obtain a preferable resin, and the content of the aliphatic epoxy compound is 2 mol% or less. On the back side, the gel content of the polyester resin is insufficient.

The branched aliphatic epoxy compound is conventionally used in the production of polyester resin for toner, but is a compound for replacing aromatic diols that may affect the environment. The aromatic diol includes a bisphenol A derivative, and such bisphenol A derivatives include polyoxyethylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (2.0) -2,2 -Bis (4-hydroxyphenyl) propane, polyoxypropylene- (2.2) -polyoxyethylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene- (2.3) -2 , 2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (6) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (2.3) -2,2-bis (4 -Hydroxyphenyl) propane, polyoxypropylene- (2.4) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (3.3) -2,2-bis (4-hydroxyphenyl) propane , Polyoxyethylene- (3.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene- (6) -2,2-bis (4 hydroxyphenyl) propane, and the like.

In addition, the reactants for the preparation of the polyester resin for toner of the present invention include aromatic dibasic acids and / or alkyl esters thereof conventionally used in the preparation of the polyester resin. Examples of such aromatic dibasic acids include terephthalic acid and isophthalic acid, and examples of the alkyl ester of the aromatic dibasic acids include dimethyl terephthalate, dimethyl isophthalate, diethyl terephthalate, diethyl isophthalate, and dibutyl terephthalate. And dibutyl isophthalate. The aromatic dibasic acid and alkyl esters thereof may be used alone or in combination of two or more thereof. Since the aromatic dibasic acid contains a benzene ring having high hydrophobicity, it improves the moisture resistance of the toner, increases the glass transition temperature (hereinafter referred to as “Tg”) of the resulting resin, and consequently improves the storage stability effect. . The amount of the aromatic dibasic acid is preferably 60 to 100 mol% (that is, the amount of the aromatic dibasic acid is 60 to 100 mol in 100 mol of the total acid), and more preferably 80 to 100 mol relative to the total acid component. %to be. In addition, since the terephthalic acid compound exhibits the effect of increasing the toughness and Tg of the resin, and the isophthalic acid compound exhibits the effect of increasing the reactivity, it may be used by changing its use ratio as desired.

In addition, the reactants for producing the polyester resin for toner of the present invention include aliphatic diols. Useful aliphatic diols include ethylene glycol, diethylene glycol, neopentyl glycol, propylene glycol, butanediol, and the like, and propylene glycol is preferably used among them in consideration of reactivity control in polyester resin polymerization. Aliphatic diols other than the propylene glycol improve the rate of polycondensation reaction, so that it is difficult to control the polymerization reaction rate, so that it may be accompanied by a sudden increase in molecular weight or gelation, propylene glycol alone or two other aliphatic diols containing second degree alcohol The above can be used in a combined form. The use amount of the aliphatic diol is preferably 55 to 98 mol%, more preferably 75 to 95 mol% with respect to the total alcohol component. Of these, the content of propylene glycol is 55 mol% or more, and the content of the remaining aliphatic diol is preferably 43 mol% or less.

The reactant for preparing the polyester resin for toner of the present invention may further include aliphatic dibasic acid, alkyl ester thereof and / or acid anhydride thereof, and non-limiting examples thereof include phthalic acid, sebacic acid, iso Aliphatic dibasic acids such as decyl succinic acid, maleic acid, fumaric acid, adipic acid, azelaic acid, monomethyl, monoethyl, dimethyl, diethyl ester and acid anhydrides thereof. Since the aliphatic dihydric carboxylic acid component has a remarkable effect on the fixability and storage stability of the toner, it is preferably 10 moles with respect to the total acid component within the range that does not impair the object of the invention according to the required performance of the resin. % Or less can be used.

The reactant for producing the polyester resin for toner of the present invention may further contain a trivalent or higher polyvalent acid, if necessary. Non-limiting examples of the trivalent or more polyvalent acid include trimellitic acid, pyromellitic acid, 1,2,4-cyclohexanetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4 -Naphthalene tricarboxylic acid, 1,2,5-hexane tricarboxylic acid, 1,2,7,8-octane tetra carboxylic acid and these acid anhydrides can be illustrated. Such trivalent or higher polyhydric carboxylic acid may be used alone or in combination of two or more thereof, and increases the Tg of the resulting resin and at the same time gives cohesion to the resin to improve the non-offset property of the toner. . Such polyacid can be used in an amount of 10 mol% or less, preferably 5 mol% or less with respect to the total acid component. If the content of the above component exceeds 10 mol%, it is difficult to control the gelation during the production of the polyester resin, and thus it is difficult to obtain the desired resin.

       The reactant for preparing the polyester resin for toner of the present invention may further include an aliphatic to aromatic monovalent basic acid for the purpose of molecular weight and polymerization reaction rate control. Non-limiting examples of the monovalent basic acid include aliphatic basic acids such as octanoic acid, decanoic acid, dodecanoic acid, myristic acid, palmitic acid and stearic acid, and may be branched or have an unsaturated group. In addition, aromatic carboxylic acids, such as benzoic acid and naphthalene carboxylic acid, can be used. These monovalent basic acids are used in the amount of 20 mol% or less with respect to all acid components. When the content of the above component exceeds 20 mol%, the glass transition point is lowered, which adversely affects the storage stability of the toner, and the target molecular weight of the polyester resin cannot be obtained.

The reactant for preparing the polyester resin for toner of the present invention may further include a trihydric or higher polyhydric alcohol, if necessary. Non-limiting examples of the trihydric or higher polyhydric alcohol include sorbitol, 1,2,3,6 -Hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1,2,4-butanetriol, 1,2,5-pentanetriol, Glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene and the like can be exemplified. The polyhydric alcohols may be used alone or in combination of two or more thereof. Such trihydric or higher polyhydric alcohols have an effect of imparting cohesiveness to the resin and improving storage stability of the toner while raising the Tg of the resulting resin. The content of the polyhydric alcohol is 10 mol% or less, preferably 5 mol% or less with respect to the total alcohol component. When the content of the polyhydric alcohol exceeds 10 mol%, it is difficult to control the gelation of the polyester resin during the production of the polyester resin, and thus it is difficult to obtain a preferable resin. When the trivalent or higher polyhydric alcohol component is used in the blended form, it is preferable that the total amount is also 10 mol% or less with respect to the total alcohol component in the above-specified range.

       The reactant for preparing the polyester resin for toner of the present invention may further include an aliphatic monohydric alcohol for molecular weight adjustment. Non-limiting examples of the monohydric alcohol include aliphatic monoalcohols such as octanol, decanol, dodecanol, myristyl alcohol, stearyl alcohol, may be branched, and may have an unsaturated group. These monohydric alcohols are used in the quantity of 20 mol% or less with respect to all alcohol components. When the content of the above component exceeds 20 mol%, the glass transition point is lowered, which adversely affects the storage stability of the toner, and the target molecular weight of the polyester resin cannot be obtained.

       In the reactant for producing the polyester resin for toner of the present invention, the molar content ratio of the total alcohol component usage to the total acid component usage is preferably 1.2 to 1.6. If the ratio (G / A) is less than 1.2, unreacted acid component is found during the polymerization reaction, the transparency of the resin is not good, the total alcohol component molar content ratio (G / A) to the total acid component mole content is 1.6 When exceeded, the polymerization reaction rate is too slow to lower the productivity of the resin.

The preparation of the polyester resin according to the present invention is carried out in two stages of esterification reaction or transesterification reaction and polycondensation reaction as in the conventional method for producing polyester resin. In order to prepare the polyester resin according to the present invention, first, the acid component and the alcohol component are charged to a reactor and heated to perform an esterification reaction or a transesterification reaction. At this time, if necessary, titanium-based catalysts generally used in esterification reaction or transesterification reaction, for example, tetraethyl titanate, acetyltripropyl titanate, tetrapropyl titanate, tetrabutyl titanate, polybutyl titanate Further known esterification catalysts or ester crosslinking catalysts, such as ethylacetoacetic ester titanate, isostearyl titanate, titanium dioxide, TiO ₂ / SiO ₂ coprecipitation and TiO ₂ / ZrO ₂ coprecipitation, can be further added. Can be. However, heavy metal antimony-based and tin-based catalysts are excluded. The esterification reaction or transesterification can be carried out, for example, at a reaction temperature of 230 to 260 ° C. under a nitrogen stream, while removing water or alcohol produced from the reactants in a conventional manner while the reaction is being carried out. After the esterification reaction or transesterification reaction is completed, the polycondensation reaction can be carried out. The polycondensation reaction may be carried out by a polycondensation reaction of a conventional polyester resin, for example, at a temperature of 240 to 260 ° C., preferably at a temperature of 250 ° C. or lower, (a) reacting the reactant as a first step of the polycondensation reaction. The reaction is carried out by high vacuum and high speed stirring, followed by (b) adjusting the high vacuum to atmospheric pressure by nitrogen charging, and performing the reaction by high-speed stirring, and finally (c) maintaining the reactor at atmospheric pressure. The reaction may be carried out by slow stirring to control the preparation of the resin, and may be performed while distilling off byproducts such as glycol. In the case of high vacuum of the first step of the polycondensation reaction, the pressure is 100 mmHg or less, preferably 30 mmHg or less, and this high vacuum gives an effect of removing the low-boiling compounds produced in the polycondensation reaction from the reaction system.

The gelling component (tetrahydrofuran (THF) insoluble content) of the polyester resin for toner according to the present invention is 5 to 30% by weight, preferably 10 to 20% by weight of the total resin component. If the gelling component is 5% by weight or less, the offset resistance of the toner at a high temperature is insufficient. If the gelling component is 30% by weight or more, the viscosity of the resin rises and mass production cannot be performed in an industrially stable state. The softening temperature of a polyester resin is 140-180 degreeC, and it is more preferable if it is 150-170 degreeC. If the softening temperature is lower than 140 ° C., the Tg is lowered and the storage stability is lowered, so that toner particles may aggregate during storage, and offset may occur at high temperatures. The softening temperature may lower the low-temperature fixability of the 180 ° C toner and cause offset. In addition, it is preferable that the Tg of the polyester resin of the polyester resin is 50 to 75 ° C. If the Tg is less than 50 ° C, the storage stability of the toner may be deteriorated. In the case of the toner manufactured by using the same, the low temperature fixability is poor and there is a fear that an excellent image cannot be obtained. Moreover, it is preferable that the acid value of a polyester resin is 1-25KOHmg / g, and it is still more preferable if it is 5-20KOHmg / g. If the acid value is less than 1KOHmg / g, the development or transfer becomes difficult, and the desired image is poor. If the acid value is more than 25KOHmg / g, the storage stability may be poor during storage and transportation of the polyester and in the developer.

The polyester resin according to the present invention is used as a main component of the binder resin of the toner, but if necessary, other resins such as styrene resin or styrene-acrylic resin may be used in combination. The amount of the binder resin used in the toner is preferably 30 to 95% by weight, more preferably 35 to 90% by weight. This is because when the binder resin content is less than 30% by weight, the toner non-offsetability tends to be lowered, and when the content exceeds 95% by weight, the charging stability of the toner tends to be deteriorated. The polyester resin produced by the present invention may be used in combination with the colorant component of the toner. Examples of such colorants and pigments include carbon black, nigrosine dyes, lamp blacks, Sudan black SM, navel yellow, mineral fast yellow, littol red, permanent orange 4R and the like. In addition, the polyester resin produced by the present invention can be used in combination with additives such as magnetic materials such as wax, charge control agent, anti-offset agent and magnetic powder which are other components of the toner. Such additives are commonly used, and examples of charge control agents include nigrosine, alkyl-containing azine dyes, basic dyes, monoazo dyes and metal complexes thereof, salicylic acid and metal complexes thereof, alkyl salicylic acid and metal complexes thereof, naphthoic acid And metal complexes thereof, and examples of the anti-offset agents include polyethylene, polypropylene, and ethylene-polypropylene copolymers. Examples of magnetic powders include ferrite and magnetite. The toner using the polyester resin prepared by the present invention as a binder resin can be prepared by a conventional method, for example, the single-screw extruder is used to binder material, colorants and additives at a temperature of 15 to 30 ℃ higher than the softening temperature of the binder resin. Toner in the form of particles can be prepared by kneading using a kneading machine such as a twin screw extruder or a mixer, and pulverizing the kneaded mixture. The average particle size of the produced toner particles is preferably 5 to 10 µm, more preferably 7 to 9 µm, and most preferably less than 3% by weight of the fine particles having a particle size of 5 µm or less.

Hereinafter, the present invention will be described in detail based on Examples and Comparative Examples, but the present invention is not limited to the following Examples. The performance evaluation method used by the following Example and the comparative example is as follows.

       (1) Gel content (wt%): A numerical value representing the amount of resin undissolved in tetrahydrofuran (THF) in 100% by weight of the resin sample in weight%. This test method is a crosslinking density of polyester (Cross- linking density). 0.1 g of the resin was weighed to 0.001 g, and placed in 100 ml of tetrahydrofuran (THF), dissolved for 2 hours with stirring, and left for 22 hours. The solution is filtered through a stainless steel 200 mesh filter to display the amount of residual resin in 100 fractions.

       (2) Tg (Glass Transition Temperature, ° C): The sample is melt-quenched using a differential scanning calorimeter (TA Instruments) and measured by heating it at 10 ° C / min. The mid value of each tangent line with the base line near the endothermic curve is Tg.

(3) Softening temperature (° C.): 1.5 g, using a flow tester (CFT-500D manufactured by Shimadzu Laboratories), under conditions of a 1.0Φ × 10 mm (height) nozzle, a 10 kgf load, and a rate of temperature rise of 6 ° C./min. The temperature at which half of the sample flows out is called the softening temperature (℃).

(4) Acid value (KOHmg / g): The resin is dissolved in dichloromethane, cooled and titrated with 0.1N KOH methyl alcohol solution.

(5) Gelation and unreacted polymerization products: When the polymerization reaction under rapid polycondensation under the same polycondensation reaction condition prevented the reactants from coming out of the reactor, gelation was defined (when the gel content is more than 30% by weight). The reaction rate was defined as unreacted when the polymerization reaction time exceeded 300 minutes or when unreacted acid component was found. Other normal reactions are defined as normal.

       (6) Grindability: The melt-extruded flakes (Flake) during the toner production were crushed with a hot water jet jet mill and a classifier (100AFG, 50ATP, 50ZPS), and the amount of toner produced per hour during classification was evaluated as follows.

       ◎: 0.4kg / 1 hour or more

○: 0.2 ~ 0.4kg / 1 hour

 X: 0 ~ 0.2kg / 1 hour

       (7) Storage stability: 100 g of the prepared toner is put in a glass bottle, sealed, and after 48 hours at 50 ° C, the degree of aggregation between the toners is visually evaluated.

(Double-circle): There is no aggregation and storage stability is favorable.

(Circle): There is fine aggregation but storage stability is favorable.

X: Agglomeration is severe and storage stability is poor.

(8) Toner Image Concentration Evaluation

Solid area image of image flow and image density (I, D) when copying onto OHP film or paper using a black and white printer with a Teflon-coated heat roller and a free temperature change and a print speed of 35 pages / minute Is measured with a Macbeth reflectometer RD918 and evaluated according to the following criteria.

◎: The image density of the image is 1.4 or more.

(Circle): The image density of an image is 1.2 or more.

X: The image density of the image is 1.2 or less.

(9) Minimum fixing temperature and offset temperature: The minimum temperature of the heat roller which coats the manufactured toner on white paper, passes the heat roller coated with silicone oil at a speed of 200 mm / sec, and maintains a fixing efficiency of 90% or more. Defining the minimum fusing temperature, the maximum temperature as the offset temperature, by adjusting the heat roller temperature from 50 ℃ to 230 ℃ to measure the minimum fixing temperature and offset temperature. The fixing temperature is defined as the offset temperature minus the minimum fixing temperature.

The abbreviation used by a present Example and a comparative example shows the following.

TPA: Terephthalic Acid

IPA: isophthalic acid

AA: adipic acid

SA: Sebaksan

AzA: Azelaisan

TMA: trimellitic acid

PMDA: pyromellitic anhydride

BzA: Benzoic acid

TMP: trimethylolpropane

      PG: Propylene Glycol

      NPG: Neopentylglycol

EG: ethylene glycol

DEG: Diethylene Glycol

ODOL: Octadecanol (= stearyl alcohol)

GTE: Glycerol Triglycidyl Ether (branched aliphatic epoxy compound)

GDE: Glycerol diglycidyl ether (branched aliphatic epoxy compound)

G / A: molar ratio of total alcohol components (including epoxy compounds) to total acid component molar contents

[Examples 1 to 11 and Comparative Examples 1 to 13]

Preparation of Polyester Resin

A 2 L reactor equipped with a stirrer and an outlet condenser was charged with the reactants of the components and the amount used as shown in Tables 1, 2, and 3 below, and the temperature of the reactor was gradually raised to 250 ° C. under nitrogen stream, and water as a byproduct was added to the reactor. The esterification reaction was carried out while flowing out. After the generation and outflow of the water was completed, the reaction product was transferred to a polycondensation reactor equipped with a stirrer, a cooling condenser and a vacuum system, 200 ppm of the catalyst was added to the monomeric acid component, the reaction temperature was raised to 250 ° C., and the reaction pressure. The excess diol component was flowed out under low vacuum reaction, reducing pressure to 50 mmHg over 30 minutes. Next, the reaction pressure was gradually reduced to 0.1 mmHg, and the reaction was performed until a predetermined stirring torque was obtained under high vacuum, thereby preparing a polyester resin. The gel content, softening temperature, Tg, and acid value of the prepared polyester resin were shown in the following table. 1, 2 and 3 are shown.

Manufacture of toner

50 parts by weight of the prepared polyester resin, 45 parts by weight of the magnetic substance 'magnetite', 2 parts by weight of the 'azo dye-based metal complex' as the charge control agent, 3 parts by weight of the 'polypropylene-based wax' are mixed using a mixer, and extruder Toner particles having a volume average particle diameter of 8 to 9 µm were prepared by melting, kneading, kneading, then pulverizing with a jet mill grinder, classifying with a wind classifier, and coating with 1 part by weight of silica and 0.2 part by weight of titanium dioxide. The pulverization property, minimum fixing temperature, offset generation temperature, storage stability, and toner image concentration evaluation results of the prepared toner particles are shown in Tables 1 and 2 below.

As shown in Table 1, the polyester resin produced by containing 2 to 15 mol% of the branched aliphatic epoxy compound in the total alcohol component according to the embodiment has a gel content of 5 to below the softening temperature of 140 to 180 ℃ It contains 30% by weight. As the softening temperature is low and the cross-linking density is high, the length of the polymer chain (number average molecular weight, Mn) decreases, so that the grinding property is improved, and the low molecular weight component of the resin exhibits melting characteristics at low temperature. The gel component of the resin exhibits elastic properties even at high temperatures. Therefore, the manufactured toner was excellent in pulverization, low temperature fixability, high temperature fixability, storage stability, and image condition. However, when the amount of the branched aliphatic epoxy compound is less than 2 mol% based on the total alcohol components as in Comparative Example 1, the gel content is lowered (5 wt% or less), resulting in poor high temperature fixability of the toner, and thus heat in the fixing unit. When the toner component melted on the pressing roller adheres and the image appears blurry, and when the amount of the epoxy compound is 15 mol% or more based on the total alcohol components as in Comparative Example 2, the gel content of the polymerization reaction product becomes too high (gel content). 30% by weight or more) The crushability and melting characteristics of the resin are lowered, making it difficult to control the gelation, so that mass production cannot be performed in an industrially stable state. As in Comparative Examples 3, 4 and 5, when gelling with a polyacid and a polyhydric alcohol without introducing a branched aliphatic epoxy compound in the preparation of the polyester resin, the gelation takes place and the molecular weight rises together to increase the softening temperature. As a result, the low temperature fixability of the toner is poor, the meltability of the resin is reduced, making it difficult to control the polymerization process conditions, and the reaction product gels during the polycondensation reaction, so that separation from the reactor is not easy. Since it was not dissolved in dichloromethane, the acid value could not be measured, and the toner could not be manufactured due to the high softening temperature.

As shown in Table 2, the physical properties of the polyester resin and the toner prepared according to Examples 7,8, and 9 were excellent, but the content of propylene glycol was 55 with respect to the total alcohol component as in Comparative Examples 6, 7, and 8. Reactions when the amount of other aliphatic diols that are less than mol% and the reaction rate is relatively high, or when the amount of polyhydric acid exceeds 10 mol% with respect to the total acid component or when the amount of polyhydric alcohol exceeds 10 mol% in the total alcohol component Due to the high speed, the reaction product gelled during the polycondensation reaction, so that it was not easy to separate from the reactor, and the acid value could not be measured because it was not dissolved in dichloromethane, which is an acid value measuring solvent. Could not. In addition, when the aliphatic dibasic acid exceeded 10 mol% with respect to the total acid component as in Comparative Example 9, the glass transition temperature (Tg) of the resin was too low to be pulverized and toner could not be produced. In addition, when the amount of monovalent acid exceeds 20 mol% with respect to the total acid component as in Comparative Example 10 or when the amount of monohydric alcohol exceeds 20 mol% with respect to the total alcohol component as in Comparative Example 11 When the monoalcohol and acid component were used to limit the growth of the polymer side chain, the resin of the target softening point could not be obtained, and the toner could not be manufactured because the softening temperature and Tg were too low.

As shown in Table 3, the polyester resins and toners prepared according to Examples 10 and 11 were excellent in physical properties such as crushability, fixing characteristics, and image density. However, as in Comparative Examples 12 and 13, when the total alcohol component molar content ratio (G / A) to the total acid component molar content was less than 1.2, unreacted acid components were found during the polymerization reaction, and the transparency of the resin was not good. When the total alcohol component molar content ratio (G / A) to the acid component molar content exceeded 1.6, the polymerization reaction rate was too slow and the productivity of the resin did not come out.

The toner made of the polyester resin according to the present invention has an advantage of excellent offset resistance and low temperature fixability, and also includes heavy metal compounds such as bisphenol (A) or its derivatives and tin or antimony as an alcohol component during polyester production. Not used, an environmentally friendly and inexpensive toner binder resin and toner can be produced.

Claims (8)

Prepared by esterification and polycondensation reaction of reactants comprising branched aliphatic epoxy compounds, aromatic dibasic acids and aliphatic diols, The content of the branched aliphatic epoxy compound and the aliphatic diol is 2 to 15 mol% and 55 to 98 mol%, respectively, based on the total alcohol component, and the content of the aromatic dibasic acid is 60 to 100 mol% based on the total acid component. Polyester resin for toner. The method of claim 1, wherein the branched aliphatic epoxy compound is erythritol, mannitol, sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripenta Erythritol, sucrose, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, Polyester resin for toner, wherein the polyhydric alcohol selected from the group consisting of trimethylol ethane, trimethylol propane and mixtures thereof is glycidylated to have 1 to 5 epoxy functional groups. delete The method of claim 1, wherein the reactant further comprises a compound selected from the group consisting of aliphatic dibasic acids, polyacids, monovalent basic acids, polyhydric alcohols and monohydric alcohols, the total aliphatic dibasic acid The amount of the polyhydric acid is 10 mol% or less, the amount of the polyhydric acid is 10 mol% or less, the amount of the monovalent basic acid is 20 mol% or less, and the amount of the polyhydric alcohol is 10 mol% with respect to the total alcohol component. It is below, and the usage-amount of the said monohydric alcohol is 20 mol% or less, polyester resin for toners.       The polyester resin for toner according to claim 1, wherein the molar content ratio of the total alcohol component usage to the total acid component usage is 1.2 to 1.6. The polyester resin for toner according to claim 1, further comprising a titanium catalyst. The gel content of the polyester resin is 5 to 30% by weight in the total resin, the softening temperature is 140 to 180 ℃, the acid value is 1 to 25KOHmg / g, the glass transition temperature is 50 to 75 Polyester resin for toner which is C. A toner manufactured by using the polyester resin according to claim 1 as a binder resin.