JP3267345B2 - Polyester resin for toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin useful as a binder resin for a dry toner used for developing an electrostatic image or a magnetic latent image in electrophotography, electrostatic recording, electrostatic printing, and the like. More specifically, the present invention relates to a polyester resin for toner having excellent charging characteristics and stable toner properties with respect to the environment.

[0002]

2. Description of the Related Art In a method for obtaining a permanent visual image from an electrostatic image, a static image formed on a photoconductive photoreceptor or an electrostatic recording medium is developed by a toner previously charged by friction. After that, it is established. In the case of a magnetic latent image, the latent image on the magnetic drum is developed with toner containing a magnetic material and then fixed. Fixing is performed by directly fusing a toner image obtained by development on a photoconductive photoreceptor or an electrostatic recording medium, or by fusing a toner image onto paper or a film and fusing it onto a transfer sheet. This is done by letting The fusion of the toner image is performed by contact with solvent vapor, pressurization and heating. There are two types of heating methods: non-contact heating using an electric oven and pressure heating using a pressure roller. The latter, which is required to be used, is used.

[0003] Toner used in the dry development system includes 1
There are two-component toners and two-component toners. A two-component toner is manufactured by first melting and kneading a resin, a colorant, a charge control agent and other necessary additives to sufficiently disperse them, then coarsely and finely pulverizing them, and classifying them into a predetermined particle size range. Is done.
The one-component toner is similarly manufactured by adding magnetic iron powder in addition to the components of the two-component toner.

[0004] Resin is a main component in the compounding of the toner and controls most of the performance required for the toner. It is required to have good pulverizability in the process, and in the use of toner, various performances are required such as good fixing property, offset property, blocking property and electric properties. Epoxy resins, polyester resins, styrene resins, methacrylic resins, and the like are known as resins used in the production of toners. For the pressure-fixing heat fixing method, styrene and (meth) acrylate are mainly used. Coalescence has been used. However, polyester resins have attracted attention because they can be fixed at lower temperatures and have excellent PVC plasticizer resistance of the fixed toner images.

[0005] However, in the polyester, a highly polar ester group contained at a high concentration in the polymer takes in moisture and causes a difference in environment, in particular, a change in humidity.
There is a disadvantage that the charge amount changes. Although some improvement by additives and the like has been reported, there is a limit, and a considerable difference cannot be denied, especially when compared with styrene-based toner which is a mainstream material of toner.

[0006] Polyester has a higher S value than styrene.
Since the P value is separated from Teflon applied to the fixing roller, it has excellent characteristics even in high temperature offset resistance.

[0007] At present, polyesters having excellent properties such as fixing property and anti-offset property are also avoided because of their poor charging properties. Currently, copiers and printers are operating at higher speeds, and in the future, there is a strong demand for resins having excellent fixing properties, and there is a strong desire for the appearance of polyesters having excellent charge amount and charge stability.

[0008]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a resin for toner having excellent thermal characteristics and charging characteristics. In particular, the present invention provides a toner binder resin having an excellent low-temperature fixing property, which is obtained by adding a charge property improver to a polyester resin, thereby realizing an increase in charge amount, an improvement in charge rise properties, and an improvement in charge stability. It is something to offer.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve these problems, and as a result, have greatly improved the electrical properties of polyester resins having excellent thermal properties such as low-temperature fixability. We found a method and completed the present invention.

That is, in order to solve the above-mentioned problems, the present invention provides (a) at least one kind of aromatic dicarboxylic acid component of 25 to 50 mol%, and (b) 5 to 45 mol% of the following formula (1): An aromatic diol component represented by the formula: (c) 5-45
Mole% aliphatic diol component (d) 10 ppm (weight)
305 ppm (by weight) of an alkali metal compound and / or an alkaline earth metal compound having a glass transition temperature of 40 to 75 ° C, a softening temperature of 85 to 170 ° C, and an acid value of 0.
An object of the present invention is to provide a polyester resin for a toner, which has a concentration of 1 to 20 mgKOH / g.

[0011]

Embedded image

Here, R represents an alkylene group having 3 or less carbon atoms, X and Y are positive integers, and the sum of X and Y is 2 or more and 7 or less.

In the present invention, the aromatic dicarboxylic acid component includes terephthalic acid, isophthalic acid, phthalic acid, 2,6
-Naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid, diphenic acid, biphenyl-4,4'-dicarboxylic acid and components derived from acid anhydrides or lower alkyl esters thereof.

The aromatic component increases the Tg of the obtained resin, contributes to blocking resistance, and has an effect on moisture resistance due to its hydrophobicity. Therefore, the aromatic dicarboxylic acid component accounts for 25 to 50 mol%, preferably 3 to 50 mol%, in the polymer.
It must be contained in an amount of 5 to 50 mol%, more preferably 40 to 50 mol%.

Of these aromatic dicarboxylic acids, terephthalic acid-based ones have an effect of increasing Tg, and isophthalic acid-based ones have an effect of increasing reactivity, so that the use balance may be changed depending on the purpose. . When the amount of the aromatic dicarboxylic acid is less than 25 mol%, the moisture resistance is reduced, and
If it is more than 0 mol%, a resin having a high degree of polymerization cannot be obtained, which is not preferable.

Examples of the aliphatic diol component include components derived from ethylene glycol, neopentyl glycol, butanediol, polyethylene glycol, cyclohexane dimethanol, hydrogenated bisphenol A, and the like. Components derived from glycol, neopentyl glycol and butanediol are preferred.

The aliphatic diol component is excellent in reactivity, and the amount of the aliphatic diol component may be determined from the viewpoint of controlling the reaction rate. The amount of the aliphatic diol component is 5 to 45 mol%, preferably 10 to 4 mol% in the polymer.
It must be contained in an amount of 0 mol%, more preferably 15 to 35 mol%. When the amount of the aliphatic diol is less than 5 mol%, the reactivity is remarkably reduced. On the contrary, when the amount of the aliphatic diol is more than 45 mol%, the reaction rate is too high to control the degree of polymerization, and the control of the gelation reaction is difficult. It is not preferable because it becomes impossible or the moisture resistance decreases.

The aromatic diol component (b) has an effect opposite to that of the aliphatic diol component, and is contained in the resin in an amount of 5 to 45 mol%, preferably 10 to 40 mol%, more preferably 15 to 40 mol%. It must be contained at 35 mol%.
When the amount of the aromatic diol component (b) is less than 5 mol%, the moisture resistance is lowered, and when it is more than 45 mol%, the reactivity is remarkably lowered, and it becomes difficult to obtain a resin having a high degree of polymerization.

In the present invention, in addition to the above components, a polycarboxylic acid component having a valency of 3 or more and / or a polyol component having a valency of 3 or more for the purpose of improving high-temperature offset resistance, and the purpose of improving moisture resistance and reactivity. Thus, an aromatic diol component other than the aromatic diol component (b), a cyclodiol component, and a monocarboxylic acid component or a monoalcohol component can be introduced for the purpose of modifying the polymer terminal. Other reactive additives and non-reactive additives may be added as long as the effects of the present invention are not impaired.

The trivalent or higher polyvalent carboxylic acid component and polyhydric alcohol component refer to components introduced from a trivalent or higher polyvalent carboxylic acid and a polyhydric alcohol. Examples of polycarboxylic acids include trimellitic acid, pyromellitic acid,
1,2,4-cyclohexanetricarboxylic acid, 2,5
There are 7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,2,7,8-octanetetracarboxylic acid and anhydrides thereof. Examples of polyhydric alcohols include
Sorbitol, 1,2,3,6-hexanetetralol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1,2,4-butanetriol, 1,2,5-pentatriol Glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol,
Trimethylolethane, trimethylolpropane, 1,
3,5-trihydroxymethylbenzene and the like can be mentioned, and these can be used alone or in combination. Such a polyfunctional group monomer has the effect of increasing the Tg of the resin, and also has the effect of imparting cohesiveness to the resin and increasing the anti-offset property. Therefore, the amount to be introduced depends on the fixing temperature and copying speed of the copying machine. It is preferably set so that it is contained within the range of 20 mol% or less in the polymer.

The aromatic diol components other than the aromatic diol component (b) include polyoxyethylene (n) -2,2
-Bis (4-hydroxyphenyl) propane (n = 2
6), polyoxyethylene (n) -polyoxypropylene (m)-(2,2) -bis (4-hydroxyphenyl)
Components derived from propane (n + m = 2 to 6), 1,4-bis (2-hydroxyethoxy) benzene and the like are exemplified. Among these, polyoxyethylene (2.2) -2,
2-Bis (hydroxyphenyl) propane is a useful raw material for controlling the reactivity. These can be used arbitrarily as long as the effects of the present invention are not impaired. The cyclo-based diol component is a diol having a cyclo ring, for example, cyclohexanedimethanol, polyoxypropylene (n)
-2,2'-bis (4-hydroxycyclohexyl) propane (n = 2 to 6), a component introduced from hydrogenated bisphenol A or the like. These can be used arbitrarily as long as the effects of the present invention are not impaired. Examples of the monocarboxylic acid component include components derived from benzoic acid, 4-t-butylbenzoic acid, and parahydroxybenzoic acid.

The monoalcohol component includes, for example, benzyl alcohol, 4-t-butyl-benzyl alcohol,
Components derived from dodecanol and one-end-blocked polyethylene glycol are exemplified. Since these monofunctional raw materials significantly inhibit the reaction, they are preferably contained in the resin in an amount of 10 mol% or less depending on the degree of polymerization of the target resin.

The resin of the present invention must contain an alkali metal compound and / or an alkaline earth metal compound, such as hydroxide, acetate, phosphate, sulfate, propionate. , Oxalate, laurate, stearate, 5-sulfoisophthalate. Addition amount is 10ppm in resin
(Weight) to 305 ppm (weight ) . These compounds have the effect of increasing the charge amount of the toner, improving the rising characteristics of the charge, and improving the charge stability. However, by setting the addition amount to 10 ppm (weight) or more, this excellent effect can be obtained.
When the content is not more than 05 ppm (weight), a decrease in the charge amount of the toner under high humidity can be suppressed, and the moisture resistance can be improved.

When an inorganic powder such as silica is added to the toner,
It is effective for improving the anti-blocking property.
The effect is particularly significant when g is low. Also,
When Tg is 50 ° C. or higher, the blocking resistance is good even without adding an inorganic powder. Therefore, Tg must be 40 ° C. or higher, preferably 50 ° C. or higher. T
If g exceeds 75 ° C., the blocking resistance is improved, but the fixability is significantly reduced.

The softening temperature needs to be in the range of 85 to 170 ° C. Generally, in the case of a resin for a full-color toner, the melt fluidity is an important property, and a lower softening temperature is preferable. However, when the softening temperature is lower than 85 ° C., the solidifying property of the toner powder increases and a blocking phenomenon is easily caused. It is not preferable.

On the other hand, if the softening temperature exceeds 170 ° C., the offset property is improved, but the fixing property is reduced. In the non-magnetic one-component system, the higher the softening temperature, the stronger the resin is given,
In some cases, the softening temperature is 170
When the temperature exceeds ℃, a problem occurs in the fixing property.

The acid value of the resin of the present invention is 0.1 to 20 mgK
Must be OH / g. Preferably, 0.5 to 15
The range is mgKOH / g. In order to obtain a polyester resin having an acid value of less than 0.1 mgKOH / g, it is necessary to minimize the thermal decomposition reaction, but this is practically impossible from the viewpoint of production efficiency. The acid value is 20 mgKOH /
Polyesters larger than g are theoretically resins in which the condensation reaction has been interrupted, which is not recommended from the viewpoint of stabilizing the quality, and is also not preferred because the hydrophilicity of the acid terminal lowers the moisture resistance.

In the present invention, for example, an esterification reaction or a transesterification reaction is carried out by charging the monomer into a reaction vessel and heating and raising the temperature. At this time, if necessary, an esterification catalyst or a transesterification catalyst such as sulfuric acid, titanium butoxide, dibutyltin oxide, and manganese acetate used in a normal esterification reaction or transesterification reaction can be used. Next, water or alcohol generated by the reaction is removed according to a conventional method.

In the present invention, the polymerization reaction is subsequently carried out. At this time, the polymerization is preferably carried out under a vacuum of 150 mmHg or less while distilling and removing the diol component. Also,
In the polymerization, a generally known polymerization catalyst, for example, titanium butoxide, dibutyltin oxide, tin acetate, zinc acetate, tin disulfide, antimony trioxide, germanium dioxide and the like can be used. The polymerization temperature and the amount of the catalyst are not particularly limited, and may be arbitrarily set as needed.

The softening temperature in the present invention is measured using a flow tester (CFT-500, manufactured by Shimadzu Corporation) using a nozzle 1.0.
Under the conditions of mmφ × 10 mmL, load of 30 kgf, temperature rise of 3 ° C./min, and sample amount of 1.0 g, the temperature at which half of the sample flowed out was taken.

In the present invention, Tg is a contact point between the tangent line of the endothermic curve near Tg and the baseline when measured at a temperature rise of 5 ° C./min with a DSC manufactured by Shimadzu.

The acid value is determined by dissolving the resin in benzyl alcohol while heating, and using cresol red as an indicator, in a benzyl alcohol solution of sodium hydroxide (1/50).
N).

[0033]

The present invention will be further described below with reference to examples. In these examples, R is a group represented by the following formula (2) in the formula (1) as the aromatic diol component (b), and X + Y
Used was 2.3.

[0034]

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Examples 1 to 3 and Comparative Examples 8 to 10 According to Table 1, acid, alcohol, alkali metal and alkaline earth metal were charged into a separable flask equipped with a distillation column.
0.03 parts by weight and 0.025 parts by weight of dibutyltin oxide and zinc acetate were added to the total acid components as catalysts, and the internal temperature was maintained at 260 ° C. and the rotation speed at 200 rpm.
After the esterification reaction under normal pressure, the pressure in the reaction system was reduced to 1.0 mmHg over 30 minutes, the internal temperature was maintained at 260 ° C., and a condensation reaction was performed while distilling ethylene glycol,
A pale yellow transparent resin was obtained. To 94 parts by weight of the obtained resin, 5 parts by weight of carbon black (Mitsubishi Kasei Corporation # 40) and a charge control agent (Orient Chemical Co., Ltd., Bontron N-0)
1) Add 1 part by weight, and use an internal mixer.
The mixture was kneaded at 70 ° C. and 65 rpm. Next, using a jet mill and a classifier, a toner having an average particle size of 10 μm was obtained.
After standing in a room at 60 ° C., 60% RH and 25 ° C., 90% RH for one day, 50 ml of 20 g of a developer obtained by adding 97% by weight of a carrier (Powdertech EFV200 / 300) to 3% by weight of this powder was added. The mixture was placed in a polyethylene container and stirred for 10 minutes with a ball mill. The charge amount of the obtained developer was measured by a Toshiba blow-off charge amount measuring device.

In addition, the evaluation of blocking resistance was carried out using 50 ml
5 g of the toner and 0.05 g of silica (Nippon Aerosil, R-972) were placed in a glass sample bottle, and the mixture was allowed to stand in a high-temperature bath at 50 ° C. for 50 hours, and then the degree of aggregation was observed. The degree of aggregation was set as follows.

The sample bottle left at 50 ° C. for 50 hours was cooled to room temperature, and the degree of aggregation was observed. A: The toner drops just by inverting the sample bottle. B: The toner drops when the sample bottle is turned upside down and shaken lightly. C: The toner drops when the sample bottle is turned upside down and lightly tapped. D: The toner drops when the sample bottle is turned upside down and vibrated. E: Even if the sample bottle is turned upside down and strong vibration is applied, the toner does not fall. According to the above criterion, it was determined that those having the cohesion degrees A, B and C were usable.

The resin composition was measured by liquid chromatography, gas chromatography and atomic absorption analysis. Table 2 shows the evaluation results of the composition and physical properties of the resin, the charge amount of the toner, and the blocking resistance.
As shown in Table 2, it can be confirmed that the resins of Examples 1 to 3 have a large charge amount and are excellent in moisture resistance and blocking resistance.

[0039]

[Table 1]

[0040]

[Table 2]

Comparative Example 1 A resin and a toner were obtained in the same manner as in Example 1 except that sodium hydroxide was not added (Table 1). Table 2 also shows the evaluation results. As shown in Table 2, it was confirmed that the toner using the resin of Comparative Example 1 had a remarkably low charge amount and easily fogged compared to the case of Example 1.

Comparative Examples 2 to 7 Raw materials were charged according to Table 3, and a polyester resin was obtained in the same manner as in Example 1. The obtained resin was made into a toner in the same manner as in Example 1, and the resin properties and the toner properties were evaluated. Table 4 shows the evaluation results. As shown in Table 4, the resins of Comparative Examples 2 to 7 were unsuitable as resins for toner because of problems such as blocking resistance, charge amount, and environmental dependency.

[0043]

[Table 3]

[0044]

[Table 4]

Evaluation Examples 1-3 , Comparative Evaluation Examples 1-4 The resins obtained in Examples 1-3 and Comparative Examples 1 , 8-10 were used, and Bontron S-34 (Orient Chemical) was used as a charge control agent. A toner was manufactured in the same manner as in Example 1 except for the above. As the evaluation of the toner, the charge amount when the stirring time was 1 minute and 10 minutes under an environment of 20 ° C. and 60% RH was measured, and the rising characteristics of the charge amount were observed. Table 5 shows the results. As shown in Table 5, it was confirmed that the toners using the resins of Examples 1 to 3 had a rapid rise in charge amount and were excellent as resins for toner.

[0046]

[Table 5]

[0047]

As described above, the resin of the present invention comprises:
Provided is a toner having a large charge amount and a rapid rise in the charge amount as compared with a conventional resin. Further, the resin of the present invention has suitable thermal properties that can be used as a resin for toner, and can be said to be a very excellent resin for toner in combination with electrical properties.

Continuation of the front page (72) Inventor Yoichi Nagai 4-1, Ushikawa-dori, Toyohashi-shi, Aichi Prefecture Inside the Mitsubishi Rayon Co., Ltd. Toyohashi Office (56) References JP-A-3-214166 (JP, A) JP-A-3 -180854 (JP, A) JP-A-3-128924 (JP, A) JP-A-59-29260 (JP, A) JP-A-3-54574 (JP, A) JP-A-1-300261 (JP, A) JP-A-63-73269 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9/08

Claims (1)

(57) [Claims] (A) 25 to 50 mol% of at least one aromatic dicarboxylic acid component, (b) 5 to 45 mol% of an aromatic diol component represented by the following formula (1), (c) )
5 to 45 mol% of aliphatic diol component (d) 10 ppm
(Weight) to 305 ppm (weight) of an alkali metal compound and / or an alkaline earth metal compound, having a glass transition temperature of 40 to 75 ° C, a softening temperature of 85 to 170 ° C,
A polyester resin for toner having an acid value of 0.1 to 20 mgKOH / g. Embedded image Here, R represents an alkylene group having 3 or less carbon atoms, X and Y are positive integers, and the sum of X and Y is 2 or more and 7 or more.
It is as follows.