JPH06118706A - Polyester resin for toner - Google Patents

Abstract

PURPOSE:To provide a polyester resin for a toner having satisfactory fixability and sufficiently high anti-offsetting property and ensuring easy control of polymn. CONSTITUTION:This polyester resin for a toner is crosslinked polyester polymerized from dicarboxylic acid, diol and a compd. having a diglycidyl group. The softening temp. of the polyester is <=170 deg.C and the glass transition temp. is 40-80 deg.C.

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 charge image or a magnetic latent image in electrophotography, electrostatic recording, electrostatic printing and the like. More specifically, the present invention makes it possible to impart a crosslinked structure to a polymer with diglycidyl, thereby providing a toner having excellent fixability, excellent offset resistance, and excellent blocking resistance.
The present invention relates to a polyester resin for toner.

[0002]

2. Description of the Related Art In a method of obtaining a permanent visible image from an electrostatic charge image, an electrostatic charge image formed on a photoconductive photosensitive member or an electrostatic recording material is developed with a toner charged in advance by friction. It will be fixed afterwards. 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. For fixing, the toner image obtained by development is directly fused on the photoconductive photoreceptor or the electrostatic recording body, or the toner image is transferred onto paper or film and then fused onto the transfer sheet. Done by. The fusing of the toner image is performed by contact with solvent vapor, pressurization and heating. The heating method includes a non-contact heating method using an electric oven and a pressure heating method using a pressure roller. Recently, the latter is mainly used as requested.

Toner used in the dry developing system is 1
There are two-component toners and two-component toners. A two-component toner is produced by first melt-kneading a resin, a colorant, a charge control agent and other necessary additives to sufficiently disperse them, then coarsely pulverizing and finely pulverizing them, and classifying them into a predetermined particle size range. To be done.
The one-component toner is manufactured in the same manner by adding magnetic iron powder in addition to the respective components of the above two-component toner.

Resins are the major components in toner formulations and dominate most of the performance required of toners. Therefore, the toner resin is required to have good dispersibility of the colorant in the melt-kneading step and good pulverizability in the pulverizing step in the toner production. It is required to have versatile performance such as good electrical and electrical properties. Epoxy resins, polyester resins, polystyrene resins, methacrylic resins and the like are known as resins used in the production of toner,
Copolymers of styrene and a (meth) acrylic acid ester have been mainly used for the pressure-bonding heat fixing system.

However, as the performance of copying machines has increased, the points of performance required for the resin for toner have also changed depending on the type of copying machine. Since polyester has good fixing properties, it has been proposed to use it in high-speed machines. Certainly, in the case of polyester, one with a low molecular weight is easy to synthesize and is very suitable in terms of fixability, but when trying to widen the molecular weight distribution in order to impart non-offset property to fixability, it is Becomes difficult to control, and it becomes difficult to stably obtain a resin having arbitrary physical properties.

It has been proposed that when a polyester resin is used as a toner, a cross-linking agent such as trimellitic acid or pyromellitic acid is frequently used to broaden the molecular weight distribution and provide fixability and non-offset property. In this case, although the obtained resin has a wide molecular weight distribution and can satisfy both the fixability and the non-offset property at the same time, it is difficult to control the reaction during the polymerization, and a resin having the same physical properties cannot be stably obtained. Further, a polymer polymerized by using a polyfunctional monomer such as trimellitic acid or pentaerythritol is subjected to stress of a kneading machine at the time of kneading, the bond is broken, and the non-offset property is lowered.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a toner resin which has good fixability, sufficient non-offset property, and easy control of polymerization. The present invention is particularly intended to provide a resin having good fixability and non-offset, and having less bond breakage during kneading by using epoxy as a polyfunctional monomer to give a three-dimensional polymer. Is.

[0008]

In order to solve the above-mentioned problems, the present invention is a polyester polymerized from a dicarboxylic acid component, a diol component and a compound having a diglycidyl group, wherein the polyester has a softening temperature of 90 ° C or higher. 17
Provided is a crosslinked polyester resin for toner, which has a glass transition point of 0 ° C or lower and a glass transition point of 40 ° C or higher and 80 ° C or lower.

In the present invention, the dicarboxylic acid component is
It is a known dicarboxylic acid used for polymerization of general polyesters, and includes aromatic dicarboxylic acids and aliphatic dicarboxylic acids. Among these, aromatic dicarboxylic acids introduced from terephthalic acid, isophthalic acid and lower alkyl esters thereof are composed of a benzene ring having strong hydrophobicity, and are therefore useful for obtaining toner moisture resistance. Examples of the lower alkyl esters thereof include dimethyl terephthalic acid, dimethyl isophthalic acid, diethyl terephthalic acid, diethyl isophthalic acid, dibutyl terephthalic acid, dibutyl isophthalic acid, etc. Is preferred. The aromatic component raises the Tg of the obtained resin, contributes to blocking resistance, and is also effective in moisture resistance due to its hydrophobicity. Among them, the terephthalic acid type has an effect of increasing Tg, and the isophthalic acid type has an effect of enhancing reactivity, so that the use balance may be changed depending on the purpose.

The most characteristic feature of the present invention is that an epoxy group is used for imparting a cross-linking structure. Since one epoxy group forms two ester groups, the epoxy monomer is used as a cross-linking agent. To be used as, one monomer must have two glycidyl groups. Specific examples thereof are trade names "Epicoat" (produced by Yuka Shell Epoxy Co., Ltd.) and "Araldite GY".
(Ciba Geigy Co., Ltd.) and those commercially available as "D.E.R." (Dow Chemical International Co., Ltd.) are useful.

[0011]

[Chemical 1]

[0012]

[Chemical 2]

[0013]

[Chemical 3]

[0014]

[Chemical 4]

[0015]

[Chemical 5]

[0016]

[Chemical 6]

[0017]

[Chemical 7]

[0018]

[Chemical 8]

[0019]

[Chemical 9]

[0020]

[Chemical 10]

[0021]

[Chemical 11]

The diol component in the present invention is a known diol component that is generally used in the condensation of polyester, and includes an aromatic diol, an aliphatic diol, or a heterocyclic diol component. Examples of aromatic diols 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, polyoxypropylene (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 (4-hydroxyphenyl) propane and the like can be mentioned, and these can be used alone or as a mixture. Since the aromatic diol has an effect of increasing Tg, the resulting resin has good blocking resistance. In addition, examples of the aliphatic diol include generally known monomers such as ethylene glycol, neopentyl glycol, and 1,4-butanediol. The aliphatic diol imparts flexibility to the resin and contributes to fixability, but T
g is lowered, and the blocking resistance is adversely affected.
These usage amounts may be set freely according to the model used.

The most important points in the present invention are that the softening temperature of the polymerized polyester is 90 ° C. or higher and 170 ° C. or lower, and the glass transition point is 40 ° C. or higher and 80 ° C. or lower. When the softening temperature exceeds 170 ° C., when it is used as a toner, the fixing property is remarkably lowered, and it is not suitable as a resin for toner. Therefore, the softening temperature needs to be 170 ° C. or lower, and preferably 165 ° C. or lower.

When an inorganic powder such as silica is added to the toner, it is effective in improving the blocking resistance, and the effect is particularly remarkable when the Tg of the binder is low.
When g is lower than 40 ° C., addition of inorganic powder such as silica has no effect and the blocking resistance is lowered.
Further, when Tg is higher than 80 ° C., the blocking resistance is sufficiently obtained, but the softening temperature becomes high and the fixability is lowered. Therefore, Tg needs to be 40 ° C. to 80 ° C., preferably 45 ° C. to 75 ° C.

In the production of the resin of the present invention, the above-mentioned monomer is charged into a reaction kettle and heated to raise the temperature to carry out an esterification reaction or a transesterification reaction. At this time, if necessary, it is possible to use an esterification catalyst or a transesterification catalyst such as sulfuric acid, titanium butoxide, dibutyltin oxide, magnesium acetate, manganese acetate or the like which is used in a usual esterification reaction or transesterification reaction. it can. Then, water or alcohol generated in the reaction is removed by a conventional method.

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

In the present invention, the softening temperature means a flow tester (GFT-500) manufactured by Shimadzu Co., Ltd. with a nozzle of 1.0 mm.
This is the temperature at which half of the shavings of the sample (1.0 g) flowed out when measured under the conditions of φ × 10 mmL, load of 30 kgf, and temperature rise of 3 ° C./min. The Tg was the contact point between the tangent line of the endothermic curve near the Tg measured at a temperature rise of 5 ° C./min with a Shimadzu DSC and the baseline.

The term "crosslinked structure" as used in the present invention means that the resin has a point at which the torque of the reaction system sharply rises during polymerization, that is, a so-called gelation point is exceeded. In addition, the compositional analysis in the examples of the present invention is one in which the resin was hydrolyzed with hydrazine and quantified by liquid chromatography.

[0029]

The present invention will now be described with reference to examples, but the present invention is not limited to these examples. Example 1 According to Table 1, 100 mol parts of terephthalic acid, 50 mol parts of polyoxypropylene (2.3) -2,2-bis (4-hydroxyphenyl) propane, 10 mol parts of diglycidyl A having the following structural formula, ethylene 65 mol part of glycol was 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, the stirring speed was kept at 200 rpm, and the esterification reaction was carried out under normal pressure for 5 hours. The pressure was reduced to 1.0 mmHg over 30 minutes, and the internal temperature was 240 ° C.
The condensation reaction was carried out for 2 hours while distilling ethylene glycol to obtain pale yellow transparent resin R-1. The Tg of the obtained resin was 70 ° C., and the results of the analysis are shown in Table 2.

[0030]

[Table 1]

[0031]

[Table 2]

^* Diol A: polyoxypropylene (2.3) -2,2-bis (4-hydroxyphenyl)
Propane ^** Diglycidyl A:

[0033]

[Chemical 12]

To 94% by weight of the obtained resin, 5% by weight of carbon black (Mitsubishi Kasei # 40) and 1% by weight of Bontron S-34 (Orient Chemical Co., Ltd.) were premixed with a Henschel mixer, and then manufactured by Kurimoto Tekko Co., Ltd. Melt-kneading was performed using an internal mixer under the conditions of 170 ° C. and 65 rpm. After the melt-kneaded product is cooled to room temperature, it is roughly pulverized with a hammer mill and then 22μ using a jet mill.
Milled to m or less. Then, using a pneumatic classifier manufactured by Nippon Pneumatic Co., Ltd., the particle size is adjusted to 5 to 22 μm, and toner T is added.
-1 was obtained. Table 3 shows the fixing test results and blocking resistance test results of Toner T-1.

[0035]

[Table 3]

Here, the non-offset fixing temperature range means that the toner is evenly sprinkled on the paper (ID = 1.0 ± 0.
3), passing through a variable temperature type fixing roller, and then peeling off the tape of the fixing portion, and obtaining the density attenuation rate. When the temperature of the roller was raised, the temperature at which the fixing rate exceeded 90% was defined as the minimum fixing temperature. Further, the temperature at which the toner began to adhere to the heat roller when the temperature was further increased was taken as the high temperature offset start temperature. The area between the lowest fixing temperature and the high temperature offset start temperature was defined as the feasible area (non-offset fixing temperature range). 100mm fixing roller speed
/ Sec, and the nip width was set to 7.0 mm for evaluation. A resin having a minimum fixing temperature of 160 ° C. or lower was defined as a resin having good fixability, and a resin having an offset at 200 ° C. or higher was defined as a resin having good non-offset properties.

The blocking resistance test method in Table 3 is as follows. That is, after sufficiently drying the toner, 5 g of the toner is put in a glass bottle having a capacity of 50 cc, and 50
Leave for 48 hours in the environment of ° C. After cooling the sample bottle, the degree of aggregation is visually observed. A: The toner drops when the sample bottle is turned upside down.

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 tapped. D: When the sample bottle is turned upside down and hit hard, the toner drops, but it aggregates into a lump. E: The toner completely fused to the sample bottle, and the toner did not fall even if the bottle was hit hard.

A measure of the degree of cohesion was evaluated on the basis of the above five grades, and A,
B and C were judged to have good blocking resistance. From Table 3, it is found that Toner T-1 has good fixability, anti-offset property, and anti-blocking property, and is suitable as a resin for toner. Example 2 Example 1 except that the monomer charge composition is as shown in Table 4.
The same operation as above was performed to obtain resins R-2 and R-3.
Table 5 shows the composition analysis results and the resin physical properties of the resins R-2 and R-3.

[0040]

[Table 4]

[0041]

[Table 5]

^* Diol A: polyoxypropylene (2.3) -2,2-bis (4-hydroxyphenyl)
Propane ^* diglycidyl B:

[0043]

[Chemical 13]

Further, the same operation as in Example 1 is carried out, and toners T-2 and T-corresponding to the resins R-2 and R-3 are used.
Got 3. Table 6 shows the results of the fixing test and the printing durability evaluation of the toners T-2 and T-3. From these results, resin R
It was found that the fixing property and the printing durability were also good when -2 and R-3 were used as the toner.

[0045]

[Table 6]

Examples 4 to 5 Example 1 was repeated except that the composition of the charged monomers was as shown in Table 7.
The same operation as above was performed to obtain resins R-4 and R-5.
Table 8 shows the results of the composition analysis of the resins R-4 and R-5, the physical properties of the resin, and the toner properties of the toner according to Example 1.

[0047]

[Table 7]

[0048]

[Table 8]

From Table 8, it can be seen that when the resins R-4 and R-5 are used as the toner, the fixing property and the blocking resistance are excellent. Comparative Examples 1 to 4 Example 1 except that the monomer charge composition was as shown in Table 9.
The same operation as above was performed to obtain resins R-6 to R-9. Table 10 shows the analysis results of Resins R-6 to R-9, the resin physical properties, and Examples.

[0050]

[Table 9]

[0051]

[Table 10]

When the resin R-6 is used as the toner, the softening temperature is as high as 178 ° C., so that the fixing property is lowered. When the resin R-7 was used as a toner, the Tg was low, so that the fixability was good and the offset resistance was slightly lowered, but the blocking resistance was good even if silica was added externally. did not become. Further, when the resin R-8 is used as a toner, Tg is as high as 83 ° C., so that the blocking resistance is extremely good, but the fixing property is deteriorated.

When no epoxy monomer was used as in the case of resin R-9, the fixability was good, but the cohesiveness of the toner was extremely lowered, and the offset resistance was deteriorated.

[0054]

As described above, according to the present invention, there is provided a toner resin which has good fixability, sufficient non-offset property, and easy control of polymerization. In particular, by using an epoxy as a polyfunctional monomer to give a three-dimensional polymer, a resin having good fixability and non-offset, and having little bond breakage during kneading is provided.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoichi Nagai 2-1, 4-Ushikawa-dori, Toyohashi-shi, Aichi Sanryo Rayon Co., Ltd. Toyohashi Plant

Claims (1)

[Claims] 1. A polyester polymerized from a dicarboxylic acid component, a diol component and a compound having a diglycidyl group, wherein the polyester has a softening temperature of 170 ° C. or lower and a glass transition point of 40 ° C. or higher and 80 ° C. or lower. A crosslinked polyester resin for toner, which is characterized in that