KR20160095866A - Polyester resin composition for toner binder, and method of preparing the same - Google Patents

Abstract

The present invention relates to a polyester resin composition for a sulfonic acid group-containing toner binder and a method for preparing the same. More particularly, the present invention relates to a saturated polyester resin composition which has improved adhesive property to be used as a toner binder and allows high-quality printing, and a method for preparing the same. Particularly, the method for preparing a polyester resin composition for a sulfonic acid group-containing toner binder comprises the steps of: I) mixing 30-50 parts by weight of an aliphatic polyhydric alcohol, 40-60 parts by weight of a divalent aromatic carboxylic acid, 1-10 parts by weight of tri-functional or higher carboxylic acid and 1-10 parts by weight of a sulfonic acid group-containing aromatic dicarboxylic acid with 0.1-1 parts by weight of a reaction catalyst, and carrying out polycondensation of the resultant mixture; and II) depressing the polycondensate under vacuum to obtain a polyester resin composition for a toner, which has a weight average molecular weight (Mw) of 10,000-50,000.

Description

TECHNICAL FIELD [0001] The present invention relates to a polyester resin composition for a toner binder and a method for preparing the toner binder,

The present invention relates to a polyester resin composition for a toner binder having a sulfonic acid group and a method for producing the same. More specifically, the present invention relates to a polyester resin (Saturated Polyester Resin) capable of high quality printing, Compositions and methods for their preparation.

The toner is classified into pulverized toner and polymerized toner according to the manufacturing method. The pulverized toner is produced by crushing a mixture of melted synthetic resin, colorant, and additive and making it into a desired size, so that the particle size is large and the surface is rough. If the roughened stone pieces are arranged, the lines will not be made right, and the pulverized toner will not be printed clearly. If the pulverulent toner is made physically, the pulverulent toner is made by chemical synthesis and is smaller and more uniform than the pulverulent toner and the surface is smooth. For this reason, the printing of the polymerizable toner becomes much clearer than that of the pulverizing formula.

Various methods such as the electrostatic recording method and the magnetic recording method have been used as the image forming method of the toner, but the most commonly used method at present is the hot pressing method. This method has an advantage of high thermal efficiency and fast fixing because the heating roller directly contacts the toner image, but there is also an offset phenomenon in which a part of the toner remains on the heating roller to contaminate the image. This phenomenon is caused by the inability to match the viscosity and elasticity of the toner, and this property is caused by the kind of the toner binder resin, the viscosity of the resin, the glass transition temperature (Tg), and the molecular weight.

Styrene / acrylic resins and polyester resins are generally used as the binder resin for toner, and polyester resins are superior in color development and transparency to styrene / acrylic resins, but have poor storage stability, hygroscopicity and fixability There are disadvantages.

Korean Patent Laid-Open No. 10-2008-0083452 (published on September 18, 2008, polyester resin composition for toner and toner)

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a toner binder polyester resin for toner which has both a glass transition temperature (Tg) and a molecular weight of the polyester resin, Compositions and methods for their preparation.

In order to achieve the above object, a polyester resin composition for a toner binder having a sulfonic acid group according to a preferred embodiment of the present invention comprises 30 to 50 parts by weight of an aliphatic polyhydric alcohol, 40 to 60 parts by weight of a divalent aromatic carboxylic acid, By weight of a polyfunctional carboxylic acid, and 2 to 10 parts by weight of an aromatic dicarboxylic acid having a sulfonic acid group.

A method for producing a polyester resin composition for a toner binder having a sulfonic acid group according to a preferred embodiment of the present invention comprises the steps of: i) mixing 30 to 50 parts by weight of an aliphatic polyhydric alcohol, 40 to 60 parts by weight of a divalent aromatic carboxylic acid, 1 to 10 parts by weight of a carboxylic acid, and 1 to 10 parts by weight of an aromatic dicarboxylic acid having a sulfonic acid group, and 0.1 to 1 part by weight of a reaction catalyst; And ii) vacuum condensing the condensed polymer to prepare a polyester resin composition for a toner having a weight average molecular weight (Mw) of 10,000 to 50,000.

According to a preferred embodiment, the method for preparing a polyester resin composition for a toner binder having a sulfonic acid group is characterized in that the polycondensation reaction is carried out stepwise by raising the temperature to 210 ° C to 240 ° C.

According to a preferred embodiment, the polyester resin composition for a toner has a final acid value of 1 to 20 mg KOH / g, a glass transition temperature (Tg) of 55 to 75 캜, and a viscosity at 230 캜 of 50 to 300 poise.

INDUSTRIAL APPLICABILITY The present invention can produce a binder polyester resin for a toner which prevents the offset phenomenon of the toner and improves the fixing performance, and is used for a binder resin of a toner such as a copying machine, a printer, and a facsimile.

In order to improve storage stability, hygroscopicity and fixability, which are disadvantages of conventional polyester resins, the present invention provides a polyester resin which is crosslinked using an aliphatic alcohol, a bivalent aromatic carboxylic acid, and a trivalent polyfunctional carboxylic acid and has a glass transition temperature (Tg) A high molecular weight can be obtained, and by introducing a dicarboxylic acid having a sulfonic acid group, a polyester resin composition for a toner having excellent fixing performance can be obtained.

Hereinafter, the polyester resin composition for a toner binder of the present invention and a method for producing the same will be described in detail.

The method for producing the polyester resin composition for a toner of the present invention is as follows.

First, 30 to 50 parts by weight of an aliphatic polyvalent alcohol (polyhydric alcohol such as Glycol, Diol), 40 to 60 parts by weight of a divalent aromatic carboxylic acid, 1 to 10 parts by weight of a trifunctional or more polyfunctional carboxylic acid, 1 to 10 parts by weight of an aromatic dicarboxylic acid and 0.1 to 1 part by weight of a reaction catalyst are mixed and then subjected to a stepwise temperature elevation step (condensation polymerization) from 210 to 240 ° C.

Then 90 minutes to 180 minutes under a vacuum gapap then, the pressure of -0.7kgf / cm ² to -0.9kgf / cm ² Final acid value of 1 to 20mgKOH / g, 50 to 300poise, glass transition when the viscosity is measured at 230 ℃ A polyester resin composition for a toner binder having a temperature (Tg) of 55 占 폚 to 75 占 폚 and a weight average molecular weight (Mw) of 10,000 to 50,000 is prepared.

In the present invention, the higher the content of the aliphatic alcohol is, the lower the glass transition temperature lowers the storage stability of the resin. However, by introducing the divalent and trivalent aromatic carboxylic acid into the polyester resin composition, Thereby securing the above problem.

Also, an aromatic dicarboxylic acid having a sulfonic acid group is introduced into an offset phenomenon, which is a problem of a high viscosity resin, to improve fixing performance, thereby producing a polyester resin composition for a toner binder capable of high quality printing.

Hereinafter, the respective components for producing the polyester resin composition for a toner binder will be described.

The aliphatic polyhydric alcohol used in the present invention is at least one selected from the group consisting of neopentyl glycol, ethylene glycol, diethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, Methyl-1,3-propanediol, trimethylolpropane, 1,6-hexanediol, and glycerin. Preferably, the aliphatic polyhydric alcohol is at least one selected from the group consisting of diethylene glycol, Ethylene glycol, 1,2-propylene glycol or neopentyl glycol.

The aliphatic polyhydric alcohol improves the rate of condensation polymerization and is attributed to the fixability of the toner, but if used excessively, the glass transition temperature (Tg) is lowered to adversely affect the storage stability of the toner. In the present invention, 30 to 50 parts by weight of aliphatic polyhydric alcohol is preferably used.

The divalent aromatic carboxylic acid used in the present invention may be at least one member selected from the group consisting of terephthalic acid, isophthalic acid, dimethylterephthalate, dimethyl isophthalate, diethyl terephthalate and diethyl isophthalate, , Isophthalic acid is used.

The divalent aromatic carboxylic acid serves to improve durability and increase the glass transition temperature. However, if it is used excessively, the storage and offset phenomenon will be defective. In the present invention, preferably 40 to 60 parts by weight of the divalent aromatic carboxylic acid is used.

The trivalent aromatic carboxylic acids (including anhydrides thereof) used in the present invention may be selected from the group consisting of trimellitic acid, trimellitic anhydride, pyrometric acid, anhydrous pyrometric acid, 1,2,4-cyclohexanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, and trimellitic anhydride and trimellitic anhydride are preferable.

Since the trivalent aromatic carboxylic acid has three functional groups, it increases the molecular weight and increases the glass transition temperature (Tg) by increasing the degree of crosslinking and plays the role of preventing the offset phenomenon. However, the trivalent aromatic carboxylic acid has a large content It is preferable to suitably use it because the viscosity increase caused by the rapid reaction after vacuum decompression which is a process of resin production. In the present invention, preferably 1 to 10 parts by weight of a trivalent aromatic carboxylic acid is used.

The aromatic dicarboxylic acid having a sulfonic acid group used in the present invention may be selected from the group consisting of 2-sulfoterephthalic acid sodium salt, 2-sulfoterephthalic acid potassium salt, 2-sulfoterephthalic acid lithium salt, terephthalic acid dimethyl-2-sulfonic acid sodium salt, potassium terephthalate dimethyl- Sulfonic acid sodium salt, terephthalic acid diethyl-2-sulfonic acid potassium salt, terephthalic acid diethyl-2-sulfonic acid lithium salt, 5-sulfoisophthalic acid sodium salt, 5-sulfonic acid sodium salt, 5-sulfoisophthalic acid potassium salt, 5-sulfoisophthalic acid lithium salt, isophthalic acid dimethyl-5-sulfonic acid sodium salt, isophthalic acid dimethyl 5-sulfonic acid potassium salt, isophthalic acid dimethyl 5-sulfonic acid lithium salt, Ethyl-5-sulfonic acid sodium salt, diisophthalic acid diethyl-5-sulfonic acid potassium salt and diisophthalic acid diethyl-5-sulfonic acid lithium salt can be used .

The aromatic dicarboxylic acid having a sulfonic acid group improves the fixation performance and contributes to the improvement of fixability of the toner. In the present invention, 1 to 10 parts by weight of an aromatic dicarboxylic acid having a sulfonic acid group is used for improving the fixability of the toner.

The reaction catalyst used in the present invention may be at least one selected from the group consisting of sulfuric acid, para toluenesulfonic acid, organic titanium compounds, organic lead compounds, organic tin compounds and germanium compounds. Preferably, Compound and an organotin compound are used, and the amount thereof is 0.1 to 1 part by weight.

Step of producing polyester resin

The present invention relates to a process for producing a binder polyester resin for toner in which the offset phenomenon of the toner is prevented and the fixing performance is improved, .

In the first step, the raw materials are charged into a glass reactor, and a small amount of nitrogen is uniformly injected into the reaction catalyst, and the temperature is gradually raised for about 4 to 6 hours until the internal temperature becomes 210 to 240 캜 The condensation reaction proceeds.

In order to carry out the condensation reaction, a suitable reaction mechanism can be used. Specifically, a stirrer (100 watts), a five-sphere glass reactor (5 liters), a heating mantle, an anchor type or paddle type stirring rod, a thermometer, a nitrogen injection tube, a flow meter, a reflux tube and a condenser can be used. The thermometer is equipped with a temperature sensor in the PDI control system and can be temperature controlled in an error range of less than 1 ° C. Preferably, a thermometer measuring up to 0.1 ° C can be used. The heating apparatus is preferably a heating mantle because of the nature of the high-temperature reaction, but the indirect heating system can also be used. It is preferred that the heating medium use an alkylindane which is volatilized or not decomposed at 300 < 0 > C. The advantage of the indirect heating system is that it keeps the internal temperature uniform, but the process can be lengthened due to the slow rise time of the temperature.

The reaction temperature of the present invention is suitably in the range of 210 to 240 ° C. If the reaction temperature is 210 ° C or less, the reaction time becomes long and the degree of polymerization of the resin becomes low and it becomes difficult to produce a polyester resin having high viscosity. ° C, the reaction time is shortened, but the color of the resin may be carbonized or discolored due to heat, and control of the viscosity becomes difficult.

On the other hand, the reason for raising the temperature step by step is that the aliphatic polyhydric alcohol is discharged together with the water generated during the condensation reaction, in order to prevent excessive release of alcohol by measuring and managing the refractive index. Since the refractive index of water is 1.3325 at 25 캜, it is preferable to control the refractive index of the condensed water from 1.3325 to 1.3345.

The reason for injecting nitrogen uniformly in the condensation reaction is to prevent the discoloration and oxidation of the resin by blocking the oxygen introduced from the upper part during the reaction and to smoothly discharge the unreacted materials and impurities at the condensation water generated at the end of the reaction, Increasing the number of collisions and increasing the reaction rate.

The second step, the vacuum process, is a vacuum process when the acid value of the resin in the heated reactor is 5 to 40 mg KOH / g and the viscosity is 1 to 30 poise at 150 ° C.

Vacuum process was put into the 90 minutes to 180 minutes vacuum pressure under a pressure of 0.7kgf / cm ² to 0.9kgf / cm ^2, and promote the crosslinking reaction rate hayeoteul final acid value of 1 to measure in 20mgKOH / g, a viscosity of 230 ℃ (Mw) of 50 to 300 poise, a glass transition temperature (Tg) of 55 to 75 占 폚, and a weight average molecular weight (Mw) of 10,000 to 50,000.

When the acid value is 1 mgKOH / g or less, the glass transition temperature (Tg) is lowered and the storage stability is poor. When the acid value is 20 mgKOH / g or more, the binder polyester resin for a high viscosity toner of the present invention has an acid value of 1-20 mgKOH / The fixing property of the toner is poor.

Further, the binder polyester resin for high viscosity toner of the present invention has a viscosity of 50 to 300 poise when measured at 230 캜. If the viscosity is less than 50 poise, an offset phenomenon occurs and fogging of the image is intensified. If the viscosity is 300 poise or more, a gelation phenomenon due to an abrupt increase in viscosity may occur as the viscosity increases.

In addition, the glass transition temperature (Tg) of the binder polyester resin for high viscosity toner of the present invention is preferably 55 ° C to 75 ° C. When the glass transition temperature (Tg) is 55 占 폚 or less, the storage stability of the resin and the toner deteriorates. When the glass transition temperature (Tg) is 75 占 폚 or more, the toner is not completely dissolved. For this reason, it is preferable that the raw materials are appropriately used in combination.

In vacuum depressurization, the reaction proceeds rapidly due to the influence of a polyfunctional carboxylic acid having 3 or more valences (including an anhydride thereof) and may cause gelation of the resin. Therefore, it is necessary to measure the viscosity by vacuum- As the amount of the trifunctional or higher polyfunctional carboxylic acid increases, gelation progresses more rapidly and control of gelation becomes more difficult, so 1 to 10 parts by weight is preferable.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the scope of the present invention is not limited to these examples.

Examples 1 to 5

A small amount of nitrogen was uniformly injected into a 5-sphere glass reactor (5 liters) in the presence of a catalyst as shown in the following Table 1, and the internal temperature was raised from 100 ° C to 230 ° C for 4-6 hours To conduct a condensation reaction.

When the final acid value was 1 to 20 mgKOH / g and the viscosity was 230 DEG C, the vacuum pressure was reduced to 50 to 300 poise to prepare a polyester resin composition for a toner.

NPG, EG and 1,2-PG were used as aliphatic polyhydric alcohols, IPA and TPA were used as bivalent aromatic carboxylic acids, TMA was used as a trivalent aromatic carboxylic acid, and aromatic dicarboxylic acids having sulfonic acid groups Sodium 2-sulfoterephthalate was used as the acid.

Comparative Examples 1 to 5

A polyester resin composition was prepared in the same manner as in the above examples except that the contents of the components added in Comparative Examples 1 to 5 were different from those in Examples. This is also shown in Table 1.

In Comparative Example 1, the content of the aliphatic polyhydric alcohol was increased. In Comparative Example 2, the content of the divalent aromatic carboxylic acid was increased. In Comparative Example 3, the aromatic dicarboxylic acid having a sulfonic acid group was not added. Comparative Example 4 shows the case where the trivalent aromatic dicarboxylic acid is not added, and Comparative Example 5 shows the case where the content of the trivalent aromatic dicarboxylic acid is increased.

Example Comparative Example One 2 3 4 5 One 2 3 4 5 NPG 10 10 5 5 15 10 10 10 10 10 EG 20 5 5 10 15 30 20 10 10 10 1,2-PG 20 25 25 20 10 20 20 20 20 20 IPA 20 20 10 30 20 20 30 20 20 20 TPA 30 30 35 30 30 30 40 20 30 30 TMA 3 3 5 7 9 3 3 3 0 12 Sodium 2-sulfoterephthalate 2 4 3 8 2 2 4 0 6 4

* NPG: neopentyl glycol

* EG: ethylene glycol

* 1,2-PG: 1,2-propylene glycol

* IPA: isophthalic acid

* TPA: terephthalic acid

TMA: Anhydrous trimellitic acid

Property measurement

The acid value, the viscosity and the glass transition temperature (Tg) of the polyester resin prepared in Examples 1 to 5 and Comparative Examples 1 to 5 were measured, and the polyester resin thus prepared was contained in the toner in an amount of 40 to 70% by weight The evaluation results of the storage stability, the fixability and the offset phenomenon are shown in Table 2, and the evaluation method is as follows.

- Acid value: The value was calculated based on the appropriate amount of KOH using the wet method (unit: mgKOH / g)

- Viscosity: Spindle 6 was tested using a Brookfield viscometer at a rate of 100 rpm at 230 ° C (in Poise)

- Vacuum decompression time: The time from vacuum decompression after completion of elevated temperature to viscosity of 50 to 300 poise when measured at 230 캜

Glass Transition Temperature (Tg): The sample was melted and cooled using a differential scanning calorimeter (SCINCO M & T), and then the temperature was measured at a rate of 10 ° C / min.

Storage stability: 50 g of the prepared toner was sealed in a glass beaker, and after aging in an oven at 50 캜 for 3 days, aggregation of the toner was observed and evaluated as follows.

○: No aggregation phenomenon

?: Slight aggregation occurred

X: Large amount of coagulation occurred

- Fusing property: When the tape was removed by attaching a tape to the printed paper, the remaining amount of the toner was observed and evaluated as follows.

&Amp; cir &: Toner remaining amount 90% or more

?: Remaining amount of toner 90 to 70%

X: residual amount of toner less than 70%

- Evaluation of offset phenomenon: The degree of fogging of the printed image was observed and evaluated when a print test was conducted using a monochrome printer.

○: Prints clearly without blurring the image

Fair: slight blurring of image occurred

X: severe blurring of image

Example Comparative Example One 2 3 4 5 One 2 3 4 5 Acid value
(mgKOH / g) 7.5 9.5 10.1 13.9 9.2 11.1 16.8 9.9 10.8 10.3 Viscosity
(poise) 310 330 363 401 465 240 320 345 180 550 Vacuum decompression time
(minute) 150 150 130 110 90 170 150 150 240 60 Glass transition temperature
(° C) 62 63 64 67 68 53 68 61 57 69 Storage stability ○ ○ ○ ○ ○ X ○ ○ △ ○ Fixability ○ ○ ○ ○ ○ ○ X X △ X Evaluation of offset phenomenon ○ ○ ○ ○ ○ △ △ X X △

As shown in Table 2, the polyester resin compositions for toner binders prepared according to the examples showed excellent storage stability, fixability, and offset phenomenon of the toner.

On the contrary, Comparative Examples 1 to 5, which differ in the content of the components, were unsuitable in some evaluations.

That is, when the content of the aliphatic polyhydric alcohol was large as in Comparative Example 1, the fixing property was good, but the glass transition temperature (Tg) was low and the storage stability was poor.

When the content of the divalent aromatic carboxylic acid was large as in Comparative Example 2, the acid value of the resin was high and the glass transition temperature was elevated, and storage stability was good, but the fixability and the offset phenomenon were poor.

As in Comparative Example 3, the absence of aromatic dicarboxylic acid having a sulfonic acid group resulted in poor fixability and offset phenomenon.

If the content of the trivalent aromatic dicarboxylic acid is smaller than that of the trivalent aromatic dicarboxylic acid as in Comparative Example 4, the viscosity of the resin is not increased but the color of the resin is also increased as the reaction time becomes longer .

If the content of the trivalent aromatic dicarboxylic acid is large as in Comparative Example 5, the reaction time is shortened due to the abrupt reaction at the time of vacuum injection, but the viscosity can not be controlled.

Claims (5)

A polyester resin composition for a toner binder having a sulfonic acid group prepared by a polycondensation reaction of a mixture containing an aromatic dicarboxylic acid having a sulfonic acid group. 30 to 50 parts by weight of an aliphatic polyhydric alcohol, 40 to 60 parts by weight of a divalent aromatic carboxylic acid, 1 to 10 parts by weight of a trifunctional or more polyfunctional carboxylic acid, and 2 to 10 parts by weight of an aromatic dicarboxylic acid having a sulfonic acid group And a sulfonic acid group prepared by polycondensation reaction of the mixture. (i) 30 to 50 parts by weight of an aliphatic polyhydric alcohol, 40 to 60 parts by weight of a divalent aromatic carboxylic acid, 1 to 10 parts by weight of a trifunctional or more polyfunctional carboxylic acid, and 1 to 10 parts by weight of an aromatic dicarboxylic acid having a sulfonic acid group And 0.1 to 1 part by weight of a reaction catalyst are mixed and polycondensed; And
ii) preparing a polyester resin composition for toner having a weight average molecular weight (Mw) of from 10,000 to 50,000 by vacuum depressurization of the condensation polymer, and a process for producing a polyester resin composition for a toner binder having a sulfonic acid group . The method according to claim 1,
Wherein the polycondensation reaction is carried out by increasing the temperature of the polycondensation reaction stepwise to 210 to 240 占 폚. The method of claim 1, wherein
Wherein the polyester resin composition for a toner has a final acid value of 1 to 20 mgKOH / g, a glass transition temperature (Tg) of 55 to 75 캜, and a viscosity at 230 캜 of 50 to 300 poise. Wherein the polyester resin composition is a polyester resin composition.