JP3267744B2 - Polyester resin for crosslinkable 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 polyester resin useful as a dry toner for developing an electrostatic image or a magnetic latent image in electrophotography, electrostatic recording, electrostatic printing, and the like. More specifically, the present invention provides a high-speed copier, a high-speed printer, and a non-magnetic toner, which requires high strength, especially in high-temperature fixing properties, because of its excellent blocking resistance, low-temperature fixing property, non-offset property, and strength. The present invention relates to a resin useful for a toner which can be mounted on a component system.

[0002]

2. Description of the Related Art In a method for obtaining a permanent visible image from an electrostatic image, an electrostatic image formed on a photoconductive photoreceptor or an electrostatic recording medium is developed with a toner previously charged by friction. Perform fixing. In the case of a magnetic latent image, the latent image on the magnetic drum is developed with a 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 transferring a toner image onto paper or a film and then fusing it on a transfer sheet. This is done by: 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. Recently, the latter is mainly used.

[0003] Toner used in the dry development system includes 1
There are two-component toners and two-component toners. The two-component toner is first melt-kneaded with a resin, a colorant, a charge control agent and other necessary additives and sufficiently dispersed, then coarsely and finely pulverized and classified into a predetermined particle size range. Manufactured. 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 the main component in the compounding of the toner and therefore controls most of the performance required for the toner. Therefore, the resin for the toner is required to have good dispersibility of the colorant in the melt-kneading step and good pulverizability in the pulverizing step in the production of the toner. In addition, various performances such as good blocking properties and good electrical properties are required. Epoxy resins, polyester resins, polystyrene resins, methacrylic resins, and the like are known as resins used in the production of toners, but copolymers of styrene and (meth) acrylic esters are mainly used for pressure-bonding and heat fixing systems. 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.

However, as the performance of the copying machine has been improved, the performance requirements of the toner resin have also changed depending on the type of the copying machine. Among them,
In particular, small copiers (portable types), which have begun to spread remarkably recently, are often used in homes and the like, and therefore have a relatively low printing rate, and the toner is charged in the developing process in the copier. Therefore, the mixing time becomes long. During that time, the toner is pulverized, the particle size becomes smaller, the charge amount changes, and the density of the copy changes. In addition, when used at home, maintenance is troublesome. Further, there is a developing system in which a toner is strongly pressed against a developing roll to charge the toner, such as a non-magnetic one component. In such a development system, the toner is easily pulverized, so that the charge amount changes very easily .

When a conventional styrene-based resin is used for the above-mentioned applications, the toner is easily pulverized due to insufficient strength of the resin, and fog is generated on a copy or the density is reduced. There is a problem. In order to improve this, a technique of making the resin ultra-high molecular weight or increasing the Tg of the resin is adopted. However, in such a method, the viscosity increases sharply, and the fixability decreases.

[0007] A polyester resin, which is considered to have relatively high strength, is also used for the toner. However, the emphasis is placed on fixing properties, so that many resins have a high cross-linking agent concentration, and the strength is reduced due to low Mn. In order to satisfy both the fixing property and the non-offset property, it has been proposed to use a polyfunctional monomer at a high concentration and expand the molecular weight distribution.However, the number average molecular weight decreases and the toughness decreases. Has become. It has also been proposed to use a propylene oxide adduct with bisphenol A to improve this brittleness. However, this monomer is very poor in reactivity, and if a large amount of this monomer is used, the reaction does not proceed to a predetermined degree of polymerization.

[0008] In order to solve these problems, it has been proposed to use a bisphenol A derivative together with a relatively reactive ethylene oxide adduct, but the bisphenol A ethylene oxide adduct reduces the Tg. Therefore, it cannot be used in large quantities. The ethylene oxide adduct of bisphenol A is
Since it is a solid, it requires pulverization when used as a monomer, which increases the cost, and a resin using this is not suitable for use in copying machines and printers, which have become popular. In addition, during the polymerization of the polymer, the ethylene oxide adduct of bisphenol A, which is a block, is difficult to be slurried at the time of charging the raw materials, and the amount of the charging is limited.

[0009]

The object of the present invention is to provide a resin for toner which has good fixing properties, non-offset properties and blocking resistance, and also has excellent toughness, and is low in cost and stable in polymerization. To provide a good resin.

[0010]

In order to solve the above-mentioned problems, the present invention provides a dicarboxylic acid component containing an aromatic dicarboxylic acid component in an amount of 60 mol% or more based on the total acid component and 30 mol% based on the total acid component. % Or more of the diol component containing the diol component represented by the formula 1 and 5 to 30 mol% of a tri- or higher polycarboxylic acid and / or a tri- or higher polyhydric alcohol with respect to the total acid component. Polyester resin,
A polyester resin for a toner, wherein the polyester has a softening temperature of 90 ° C or higher and 180 ° C or lower, a glass transition point Tg of 40 ° C or higher and 80 ° C or lower, and a toughness index of 250 to 600 µm. I do.

[0011]

Embedded image

The aromatic dicarboxylic acid component referred to in the present invention means a unit introduced from terephthalic acid, isophthalic acid or a lower alkyl ester thereof. Aromatic dicarboxylic acid is useful for obtaining the moisture resistance of the toner because it has a strongly hydrophobic benzene ring. These lower alkyl esters include dimethyl terephthalate, dimethyl isophthalate, diethyl terephthalate, diethyl isophthalate, dibutyl terephthalate, dibutyl isophthalate, and the like, but dimethyl terephthalate and dimethyl isophthalate are preferred in terms of cost and handling. Is preferred. The aromatic dicarboxylic acid has an effect of increasing the Tg of the obtained resin, and improves the blocking resistance of a toner using the same. Above all, terephthalic acid-based compounds improve toughness and Tg.
It has the effect of above, isophthalic acid enhances the reactivity
At the same time, there is an effect of imparting flexibility to the resin and contributing to the fixing property, so that the usage balance may be changed depending on the purpose. Such terephthalic acid or isophthalic acid component is preferably used in an amount of 60 mol% or more of all acid components.
Especially preferably, it is 70 mol% or more.

Examples of other dicarboxylic acids used together with the above aromatic dicarboxylic acid component include phthalic acid, sebacic acid, isodecyl succinic acid, maleic acid, fumaric acid, adipic acid, and monomethyl, monoethyl, dimethyl, and the like thereof. , Diethyl esters and the like and acid anhydrides thereof. These dicarboxylic acid components greatly affect the fixability and blocking resistance of the toner. These can be used in amounts within the above-described range according to the required performance of the resin.

In the present invention, the diol represented by the formula (1) needs to be present in an amount of 30 mol% or more based on all the acid components. The diol of the formula 1 is obtained by reacting ethylene oxide with one OH group of bisphenol A and reacting propylene oxide with the other OH group. Since the property is a viscous liquid, the cost is low. In addition, raw materials can be smoothly fed during polymerization. Further, the most significant effect is that the resin can have toughness while achieving low viscosity and high Tg. If necessary, an ethylene oxide adduct or a propylene oxide adduct of bisphenol A can be used in combination.

When the amount of the diol of the formula (1) is less than 30 mol%, when the viscosity is lowered, the Tg is low, and a product which satisfies both the melting color mixing property and the blocking property for a full color cannot be obtained. Therefore, the amount of the diol 1 needs to be 30 mol% or more, preferably 40 mol% or more, based on all the acid components. Other diols that can be used with the diols of Formula 1 include the usual aliphatic and aromatic diols commonly used in making polyesters. Specific examples of the aliphatic diol include ethylene glycol, neopentyl glycol, propylene glycol, butanediol, polyethylene glycol, and the like.
These are used alone or in combination. These aliphatic diols have an effect of increasing the rate of the condensation polymerization reaction. Among these, ethylene glycol, neopentyl glycol and butanediol are preferred from the viewpoint of fixability. Aliphatic diols increase reactivity,
Flexibility was imparted to the resin, contributes to fixability, contrary Tg
And adversely affects the blocking resistance . others
Therefore, if the amount of aliphatic diol used is set according to the purpose,
Good .

Examples of the aromatic diol include polyoxyethylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane and polyoxypropylene- (2.
0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2.2) -polyoxyethylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxy Propylene (6) -2,2
-Bis (4-hydroxyphenyl) propane, polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (2.
4) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3.3) -2,2-bis (such as 4-hydroxyphenyl) propane can be cited, they are alone or in a mixture used. Aromatic diol has an effect of enhancing the toughness and Tg, but blocking resistance is improved. On the other hand when used in a large amount
The reactivity decreases, and a high molecular weight polyester resin is obtained.
Absent. Therefore, the amount of aliphatic diol used depends on the purpose.
And set it .

The most important points in the present invention are that the polyester has a softening temperature of 90 ° C. to 180 ° C., a Tg of 40 ° C. to 80 ° C., and a toughness index of 250 to 600 μm. It is in. When the softening temperature is 90 ° C. or lower, the fixing property is improved, but the cohesive force of the resin is extremely reduced, and a sufficient non-offset property cannot be obtained. Further, when the softening temperature is 180 ° C. or higher, the non-offset property is improved, but the fixing property is extremely reduced, and thus the resin is not suitable for a resin for toner. Therefore, the softening temperature is 9
The temperature must be 0 ° C or higher and 180 ° C or lower, preferably 95 ° C to 170 ° C.

When an inorganic powder such as silica is added to the resin, the blocking resistance is improved, and the effect is more remarkable as the Tg becomes lower. However, with respect to a resin having a Tg of 40 ° C. or lower, even if an inorganic powder is added, the blocking resistance is not improved. The resin having a Tg of 50 ° C. or higher has good blocking resistance even without adding an inorganic powder. Therefore, Tg needs to be 40 to 80 ° C, and preferably 50 to 70 ° C.

In the present invention, a trivalent or higher polyvalent carboxylic acid and a polyhydric alcohol component are used in order to provide a crosslinked structure, but they are introduced from a trivalent or higher polyvalent carboxylic acid and a polyhydric alcohol. It is the component which was done. Examples of polycarboxylic acids include trimellitic acid, pyromellitic acid, 1,2,4-cyclohexanetricarboxylic acid,
There are 5,7-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 are used alone or in combination. Such a multifunctional monomer has a resin toughness and Tg.
With an effect of increasing a cohesiveness imparting to the resin, the effect increasing the offset resistance there Ru.

In the present invention, the most important point is that the polymerized
esterresinIs given toughnessYou.
To impart toughness to polyester resin,
It is necessary that the resin has an appropriate cross-linking structure.
In this case, the amount of the polyfunctional monomer used is
Less than 30 mol%It is necessary and good
Preferably 20 mol% or less, more preferably 15 mol%
Is below. When a multifunctional monomer is used at a high concentration, 3
The reaction of the three-dimensional structural part becomes preferential, and sufficient for the polymer
It becomes difficult to provide strength. For more information, see Polymer
The gel point is reached before the main chain of the
The melt viscosity of the polymer itself begins to form a textured structure
But the strength of the resin decreases.Furthermore, the present invention
In addition to having a moderate crosslinked structure in the resin,
Terephthalic acid, naphthalene ring derivative, bisphenol
Derivatives, alicyclic compounds such as cyclohexane ring, etc.
By using structurally strong monomers,
High toughness can be imparted to the steal resin.

In the present invention, the toughness evaluation of the resin is as follows.
The following method is used. (1) General crushed resin is sieved to a particle size of 1400 to 2
50 g of a 000 μm sample is prepared. (2) Finely pulverize 30 g of the pulverized product of (1) with a blender TR-BL manufactured by Trio Science (scale 10:30).
Seconds).

(3) Assemble the sieve having the measured weight in the order shown in FIG. (4) Weigh 20 g of the pulverized material obtained in the operation of (2). (5) This finely pulverized product is put on the top of the sieve assembled in (3), and is vibrated for 30 minutes with a micro-type electromagnetic vibration sieve M-2 manufactured by Tsutsui Rikakiki (scale: 10).

(6) Weigh the weight of the resin on each sieve. (7) Each value is plotted on a semi-logarithmic graph (cumulative weight of each mesh pass), and 50
Read the particle size that the weight percent passes. In the above evaluation method, when a toner having a particle size of 250 μm or less is used, the toughness of the toner is weak, the toner is pulverized during development in a copying machine, the charge amount of the toner is changed, and the image density is reduced. Will have an effect.

When a toner using a resin having a particle size of 600 μm or more is used in the above evaluation method, the strength of the resin is good, and pulverization in a copying machine and generation of spent toner can be suppressed. Since the strength is high, the fixability, which is an important factor as a toner, is reduced. Therefore, the pulverized particle size needs to be 250 to 600 μm, preferably 300 to 550 μm, according to the above evaluation method.

In the production of the resin of the present invention, the above-mentioned monomer is charged into a reaction vessel and heated to raise the temperature to carry out an esterification reaction or a transesterification reaction. At this time, an esterification catalyst such as sulfuric acid, titanium butoxide, dibutyltin oxide, magnesium acetate, and manganese acetate, which is used in a normal esterification reaction or transesterification reaction, can be used, if necessary. Then, water or alcohol generated by the reaction is removed according to a conventional method. Subsequently, a polymerization reaction is carried out. At this time, the polymerization is carried out under a vacuum of 150 mmHg or less while distilling and removing the diol component. Also, toughness and high
In order to give a high Tg, the monomer is charged into the reactor.
At the same time, make the charged molar ratio of the acid component and the alcohol component equal.
It is preferable to use an alcohol for the acid component.
It is preferable that the molar ratio of the
More preferably, it is 1.2 or less. Furthermore, like this
If the molar ratio of the alcohol component is reduced, the reaction
Esterification reaction or transesterification
Performing the reaction at a high temperature of 250 ° C or higher and under high pressure
Is preferred.

In the present invention, the softening temperature is 1 mm using a flow tester CFT-500 manufactured by Shimadzu Corporation.
φ × 10mm nozzle, load 30Kf, heating rate 3 ℃ / min
When measured at a constant temperature rise of 1 /
2 refers to the temperature at which it flows. Tg is the temperature at the intersection of the base line of the chart and the tangent to the endothermic curve near Tg when measured at a heating rate of 5 ° C./min using a differential scanning calorimeter.

In the composition analysis in Examples in the present invention, the resin was hydrolyzed with hydrazine and quantified by liquid chromatography.

[0028]

Next, the present invention will be described with reference to examples, but the present invention is not limited to these examples. Example 1 As shown in Table 1, 56 mol parts of terephthalic acid, 30 mol parts of isophthalic acid, 14 mol parts of trimellitic acid, and 50 mol parts of diol A (diol represented by the above formula 1, same in the following examples) And 70 mol parts of ethylene glycol were charged into a reaction vessel having a distillation column. 0.08 parts by weight of dibutyltin oxide as a catalyst was added to all the acid components, the internal temperature was kept at 260 ° C., and the stirring rotation speed was kept at 200 rpm.
After the esterification reaction under normal pressure for 5 hours, the pressure in the reaction system was reduced to 1.0 mmHg over 30 minutes, the internal temperature was maintained at 240 ° C, and the condensation reaction was performed for 2 hours while distilling ethylene glycol, and the light yellow color was obtained. Was obtained. The Tg of the obtained resin was 60 ° C., and the toughness evaluation result was 400 μm.
Met. Table 2 shows the results of the composition analysis.

[0029]

[Table 1]

[0030]

[Table 2]

To 94% by weight of the obtained resin, 5% by weight of carbon black (Mitsubishi Chemical # 40) and 1% by weight of Bontron S-34 (Orient Chemical Industries) were premixed with a Henschel mixer, and then manufactured by Kurimoto Tekko Melt kneading was performed at 170 ° C. and 65 rpm using an internal mixer. After cooling the melt-kneaded product to room temperature, it was coarsely pulverized by a hammer mill, and then 22 μm was jet-milled.
m or less. Then, using a pneumatic classifier of Nippon Pneumatic Co., Ltd., the toner T was adjusted to a particle size of 5 to 22 μm.
-1 was obtained. A fixing test and a printing durability test were performed using a non-magnetic one-component printer in which the toner T-1 was modified into a variable temperature type. Table 3 shows the test results.

[0032]

[Table 3]

Here, the fixing temperature is defined as the initial density ID = 1.0 ±
Pass the 0.3 part through a temperature-variable fixing roller, then peel off the tape at the fixing part, calculate the density decay rate, and when the temperature of the roller is raised, the fixing rate exceeds 90% Is the fixing temperature. The fixing roller speed was set to 100 mm / sec, and the nip width was set to 8.0 mm for evaluation. Minimum fixing temperature is 160 ℃
The following were used as resins having good fixability.

Further, a printing durability test was carried out with a copying machine of an actual non-magnetic one-component system, and the image change after copying 5,000 sheets was visually evaluated. The evaluation was evaluated as follows. A: A clear image was obtained from the beginning to the end. B: Image density slightly changed in the middle, but was judged to be good throughout.

C: A good image was obtained up to 1000 printing presses. D: The image deteriorated from the beginning of the printing durability test. Tables 2 and 3 show that when the resin R-1 was used as the toner resin, the fixing behavior was good and the printing durability was excellent. Examples 2 and 3 The same operations as in Example 1 were carried out except that the monomer charging composition was as shown in Table 4, to obtain resins R-2 and R-3. Table 5 shows the results of the composition analysis and the resin physical properties of the resins R-2 and R-3.

[0036]

[Table 4]

[0037]

[Table 5]

Further, the same operation as in Example 1 was carried out, and toners T-2 and T- corresponding to resins R-2 and R-3 were used.
3 was obtained. Table 6 shows the results of the fixing test and the printing durability evaluation of T-2 and T-3. From these results, it can be seen that when R-2 and R-3 are used as the toner resin, the fixability and the printing durability are good.

[0039]

[Table 6]

Examples 4 and 5 The same operations as in Example 1 were carried out except that the monomer charging composition was as shown in Table 7, to obtain resins R-4 to R-5. Table 8 shows the results of the composition analysis of the resins R-4 and R-5, the physical properties of the resins, and the toner characteristics when the toner was made in accordance with Example 1.

[0041]

[Table 7]

[0042]

[Table 8]

From Table 8, it can be seen that when R-4 and R-5 were used as toner resins, they had excellent fixing properties and printing durability.

Comparative Examples 1 to 5 Resins R-6 to R-10 were obtained in the same manner as in Example 1, except that the charged monomer composition was changed as shown in Table 9.
Table 10 shows the analysis results, the resin physical properties of the resins R-6 to R-10, and the toner characteristics when the toner was made according to Example 1.
Shown in The diol B in the table is polyoxypropylene (2.3) -2,2-bis (hydroxyphenyl) propane (the same in the following examples).

[0045]

[Table 9]

[0046]

[Table 10]

R-6 did not react to the gel point even after reacting for 10 hours with the above composition because the amount of the polyfunctional monomer used was small. R-7, on the contrary, had a large amount of the polyfunctional monomer of 50 mol%, so that the reaction did not stop at an arbitrary degree of polymerization and runaway, so that the polymer could not be discharged from the flask. R-8 uses a small amount of diol A, and when it is used as a toner, the strength of the toner is reduced and cannot be used in a system requiring toughness.

R-9 has a low Tg and very good fixability, but has extremely poor blocking resistance.
R-10 has a very high Tg and very good blocking resistance and toughness, but has poor fixability, and is not suitable for a high-speed machine or a system requiring low energy fixing.

Comparative Examples 6 to 8 Resins R-11 to R-13 were obtained in the same manner as in Example 1, except that the monomer charge composition was changed as shown in Table 11. Table 1 shows the analysis results of R-11 to R-13, the physical properties of the resin, and the toner characteristics when the toner was made according to Example 1.
It is shown in FIG.

[0050]

[Table 11]

[0051]

[Table 12]

R-11 and R-12 are examples of a case where the softening temperature is low and a case where the softening temperature is high. When the softening temperature is as high as 185 ° C. as in R-11, if the resin becomes soft even when heat is applied. And the fixability is lowered. Further, when a resin having a low softening temperature, such as R-12, is converted into a toner, the fixability is good, but the Tg and the toughness are reduced. Also, R
When the toughness is extremely increased as in -13, the fixability of the resin is reduced.

[0053]

As described above, according to the present invention, the fixing property, the non-offset property and the blocking resistance are good.
Further, a resin for toner having excellent toughness is provided.
This resin is inexpensive and has good polymerization stability.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an assembling order of a sieve used for evaluating toughness of a resin.

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoichi Nagai 4-1, Ushikawa-dori, Toyohashi-city, Aichi Prefecture Mitsubishi Rayon Co., Ltd. Toyohashi Works (56) References JP-A-63-61018 (JP, A) JP-A-4-40470 (JP, A) JP-A-3-128924 (JP, A) JP-A-1-105957 (JP, A) JP-A-2-82 (JP, A) JP-A-58-127938 ( JP, A) JP-A-63-193155 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9/08 CA (STN)

Claims (1)

(57) [Claims] 1. A diol component containing a dicarboxylic acid component containing at least 60 mol% of an aromatic dicarboxylic acid component with respect to the total acid component and a diol component containing at least 30 mol% with respect to the total acid component with a diol component represented by the formula 1. And 5 to 30 mol% based on all acid components
Is a polyester resin polymerized from a trivalent or higher polycarboxylic acid or / and a trivalent or higher polyhydric alcohol, wherein the polyester has a softening temperature of 90 ° C or higher and 180 ° C or higher.
A polyester resin for a toner having a glass transition point Tg of not less than 40 ° C. and not more than 80 ° C. and a toughness index of 250 to 600 μm. Embedded image