JPH01174518A - Epoxy resin for toner and toner for developing electrostatically charged image using said resin as binder resin - Google Patents

Abstract

PURPOSE:To obtain an epoxy resin for toners, having excellent low-temperature high speed fixing properties without causing offset and suitable as a binder resin for developing electrostatically charged images, by containing a (hydrogenated) bisphenol type epoxy resin and acid anhydride in a specific proportion. CONSTITUTION:An epoxy resin for toners obtained by blending a bisphenol type and/or hydrogenated bisphenol type epoxy resin (preferably bisphenol A type epoxy resin) with an acid anhydride (preferably methyltetrahydrophthalic anhydride, etc.) in an amount to provide 0.02-0.2mol. based on 1 equiv. epoxy group in the above-mentioned epoxy resin and preferably reacting both in the presence of a catalyst, such as sodium hydroxide, at 100-200 deg.C. The above- mentioned epoxy resin is used as a binder resin to afford a toner for developing electrostatically charged images.

Description

Detailed Description of the Invention <Field of Industrial Application> The present invention relates to an electrophotographic toner used for electronic copying, facsimile, etc., and in particular to an epoxy resin for toner that can be fixed at a low temperature and does not cause offset, and an epoxy resin for toner using the same. The present invention relates to a toner for developing an electrostatic image using a binder resin.

<Prior Art> Developers used in electrophotography are known to be of a -component type and a two-component type.

A two-component developer is a mixture of a colored powder (toner) and a carrier, which is a charged particle. In the toner,
Contains coloring agents such as pigments and dyes, binder resin, lubricants, and other additive components.

In electrophotography, the general methods for fixing toner on a substrate such as paper are pressure fixing, in which the toner is passed between two or more metal rolls and fixed by mechanical pressure, and heat fixing, in which the toner is heated above its melting point and fused. There are a fixing method and a heat pressure (heat roll) fixing method which is a combination of the above two methods.

Among these, the heat-pressure fixing method is superior in terms of high-speed copying performance, but because the toner comes into contact with the heat roll in a molten state, a part of the toner adheres to the heat roll surface and rolls three times, causing so-called offset. . The melting state of the toner at which such offset occurs is mainly determined by the melting point of the binder resin in the toner.

Various resins such as polyethylene, styrene-acrylic copolymers, polyesters, and epoxy resins have been proposed as binder resins.

Among these, styrene resin has been widely used since it is less prone to offset and has excellent high-temperature fixing properties.

However, in recent years, as the scope of use of electrophotography has expanded and it has begun to be applied to home appliances, a need has arisen for reducing power consumption. In particular, in color copying, it is necessary to fix the toner on the entire surface, so it is necessary to lower the fixing temperature of the toner.

Furthermore, high-speed fixing performance is also required as a terminal for high-speed equipment such as computers.

In terms of reducing power consumption in the heat roll and achieving high-speed copying, it is advantageous for the toner and eventually the binder resin to have a lower melting point. Therefore, when an epoxy resin is used as the binder resin, since the resin has a lower melting point than a styrene resin, a toner with good fixing properties at low temperatures can be easily obtained.

In addition, styrene resin is dioctyl phthalate (DOP)
Because the toner dissolves in PVC plasticizers such as PVC, there is a problem that if copies are stored in contact with a soft PVC film, the toner from the printed matter will adhere to the film and contaminate the film. However, epoxy resin has the advantage that such a phenomenon does not occur.

However, since epoxy resins have a low molecular weight and low melt viscosity, there is a problem in that offset tends to occur.

In particular, in general bisphenol type or hydrogenated bisphenol type epoxy resins, the lower the melting point of the resin, the lower the molecular weight, so offset tends to occur more strongly.

On the other hand, in the thermal fixing method, if a resin with a low melt viscosity is used for the toner, voids are likely to occur during fixing, resulting in poor appearance of the printed matter. In order to solve this problem, a resin with a low melting point and high melt viscosity is desired as a resin for toner.

<Problems to be Solved by the Invention> An object of the present invention is to solve the above-mentioned problems in the prior art, and to provide an epoxy resin for toner that has excellent low-temperature fixing properties and high-speed fixing properties and does not cause offset, and a static static resin using the same. An object of the present invention is to provide a toner for developing a charge image.

Means for Solving Problems> The first aspect of the present invention is to add acid anhydride to 1 equivalent of epoxy group in bisphenol type and/or hydrogenated bisphenol type epoxy resin in an amount of 0.02 to 0. An epoxy resin for a toner is provided, characterized in that the epoxy resin is contained in a proportion of 2 moles.

In a second aspect of the present invention, as a binder resin, an acid anhydride is added at 0.00% per equivalent of epoxy group of a bisphenol type and/or hydrogenated bisphenol type epoxy resin.
Provided is a toner for developing electrostatic images characterized by containing a resin in a proportion of 2 to 0.2 moles.

<Structure of the invention> The configuration of the present invention will be explained in detail below.

The toner of the present invention is characterized by the toner epoxy resin used as the binder, and uses an epoxy resin having the following components.

(a) Bisphenol type and hydrogenated bisphenol type epoxy resins are epoxy resins obtained from bisphenol and epichlorohydrin, or resins obtained by hydrogenating these resins.

These resins may be used alone or in a mixture of 2 f1 or more.

As the epoxy resin of component (a), bisphenol A
Bisphenol-type epoxy resin such as 1-bisphenol F, 1.1-bis(4-hydroxyphenyl)ethane, 1
．． 1-bis(4-hydroxyphenyl)cyclohexane, 1.1-bis(4-hydroxyphenyl)-1-phenylethane, bis(4-hydroxyphenyl)sulfone, bis(4-hydroxyphenyl)ether, halides thereof and those obtained by glycidylating bisphenols such as these hydrogenated compounds with epichlorohydrin or β-methylepichlorohydrin.

Particularly preferred is bisphenol A type epoxy resin.

(b) Acid anhydride is a compound formed by the condensation of two carboxyl groups of a polybasic acid represented by the formula (RCO) 20 and loss of water, such as phthalic anhydride, trimellitic anhydride, pyroanhydride Mellitic acid, benzophenone tetracarporic anhydride, ethylene glycol bis(anhydrotrimellitate), glycerol tris(anhydrotrimellitate), maleic anhydride, succinic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, Examples include methyl nadic anhydride, alkenyl cohelic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylcyclohexenetetracarboxylic anhydride, chlorendic acid anhydride, and tetrabromophthalic anhydride.

Particularly preferred are methyltetrahydrophthalic anhydride and hexahydrophthalic anhydride.

When component (b) is reacted with component (a), the resulting epoxy resin exhibits a higher melt viscosity compared to the original component (a) type epoxy resin having the same softening point.
Therefore, in the heat-pressure fixing method, offset is less likely to occur even with a resin having a low softening point.

Further, the generation of voids can be suppressed in the heat fixing method.

The ratio of component (a) and component (b) is such that component (b) is reacted in a ratio of 0.02 to 0.2 mol per 1 equivalent of epoxy group in component (a).

If necessary, the epoxy group of the epoxy resin obtained by reacting component (a) and component (b) is further reacted with m active hydrogen compounds such as phenols, secondary amines, and -valent carboxylic acids, It can also be used as a binder resin in a state in which the epoxy groups are consumed.

The epoxy resin used in the toner of the present invention contains the above components (
In addition to a) and (b), styrene-acrylic resin olefin oligomer resin, etc. may be added to the extent that the properties of the epoxy resin for toner are not impaired, and other necessary charge control agents, flow control agents, etc. may be added. May be added.

Toner components other than the above-mentioned epoxy resin used in the binder may be pigments, dyes, release agents, etc. that are commonly used, and are not particularly limited.

Next, a method for producing the toner and epoxy resin for toner of the present invention will be described, but the present invention is not limited to these production methods.

The reaction of component (a) and component (b) is carried out in the presence of a catalyst and optionally a solvent at a temperature of about 50-250°C, preferably about 1
It is generally carried out at a temperature of 00-200°C.

If desired, components (a) and (b) may also be added during this reaction.
) Other bisphenols and/or primary amines may also be present to carry out this reaction while extending the chain.

Separately, the reaction between component (a) and component (b) involves reacting a low molecular weight epoxy resin with bisphenols to raise component (a) to the desired molecular weight, while at the same time reacting component (b). This can also be done by coexisting.

Examples of catalysts include alkali metal hydroxides such as sodium hydroxide and lithium hydroxide, alkali metal alcoholides such as sodium methylate, tertiary amines such as dimethylbenzylamine, triethylamine, and pyridine;
Quaternary ammonium salts such as tetramethylammonium chloride and benzyltrimethylammonium chloride, organic phosphorus compounds such as triphenylphosphine and triethylphosphine, quaternary phosphonium salts such as triphenylphosphine/methyl iodide adduct, sodium carbonate, lithium chloride, etc. Alkali metal salts of , Lewis acids such as boron trifluoride, aluminum trichloride, and silver tetrachloride, complexes such as boron trifluoride/diethyl ether adducts, etc. are generally used in a proportion of about 0.01 to 100QOpp■
, preferably about 0.1 to 1000 ppm.

When a solvent is used, one having neither active hydrogen nor ester group is used, such as hydrocarbons such as toluene and xylene, and ketones such as methyl isobutyl ketone, methyl ethyl ketone, and cyclohexanone.

To produce a toner using the above-described epoxy resin for toner as a binder, for example, a dye such as nigrosine dye, a pigment such as carbon black, a charge control agent, a mold release agent, etc., and the epoxy resin for toner of the present invention are respectively added. As a powder,
The toner for developing an electrostatic image of the present invention is produced by kneading with an extruder or the like.

<Example> The present invention will be specifically explained below with reference to Examples.

(Example 1) □Synthesis of resin□ Epoxy equivalent taag/equivalent bisphenol A epoxy resin 4000g, bisphenol A 1127g
, 500 g of xylene was placed in a container equipped with a thermometer and a stirring device.
In addition to 01 separable flask, 120 ml under N2 atmosphere.
The temperature was raised to ℃.

To this was added 8 g of triphenylphosphine O as a catalyst dissolved in 50 g of xylene.

Next, the temperature was raised to 150° C. while removing xylene by distillation under reduced pressure. After xylene distillation, return to N2 atmosphere,
A Fhr reaction was carried out at 150°C to obtain an epoxy equivalent of 4F Og/
An epoxy resin having a softening point of 67° C. as measured by the durance method was obtained.

In addition, 75 g of 4-methyl-1,2,3,6-titrahydrophthalic anhydride, 2.4.6-tris(N%N-dimethylaminomethyl)phenol o, ag as a catalyst
was added, and a reaction was carried out at 170°C for 3 hours.

This results in an epoxy equivalent stsg/equivalent and a softening point of 82°C.
, Melt flowability (MI90°C) measured according to JIS K-7210 at a temperature of 90°C and a load of 500g.
Epoxy resin (I) of 15 g/l 0 ml was obtained.

Note that the same result was obtained even when 3-methyl-1,2,3,6-titrahydrophthalic anhydride was used instead of 4-methyl-1,2,3,6-titrahydrophthalic anhydride. .

□ Preparation of toner □ 100 parts by weight of the epoxy resin (I) obtained above, 2 parts by weight of nigrosine dye (Orient Kagakuten N-04), 6 parts by weight of carbon black (manufactured by Mitsubishi Kasei, $30), polyethylene wax (molecular weight 900, density 0.9218/c
m3, melting point: 105° C.) was kneaded using a kneader, cooled, and then ground to produce a toner having an average particle size of about 13 to 15 μm, which was used as a sample.

A developer was prepared by mixing 5 parts by weight of this toner with 95 parts by weight of an iron powder carrier having an average particle size of about 60-100 .mu.m.

□Evaluation□ After developing an electrostatic latent image formed by ordinary electrophotography using this developer, the toner image is transferred onto transfer paper, and the surface is made of "RTV" (silicon rubber manufactured by Shin-Etsu Chemical). After fixing using a fixing roller, fixing properties and offset properties were evaluated.

(1) Fixability The transfer paper after fixing was evaluated by rubbing it with an eraser.

○ Good = 80% or more remaining Δ Slightly bad 280-20% remaining × Bad: 20% or less remaining (2) Offset property Offset properties were evaluated from the transfer paper after fixing.

O Absent Δ Slightly present

The results are shown in Table 1.

(Example 2) In Example 1, 4-methyl-1,2,3°6-titrahydrophthalic anhydride and 2°4.8-)-lis(N
, N-dimethylaminomethyl)phenol was used, except that the amounts used were changed to 150 g and 1.5 g, respectively.

A toner was prepared and evaluated in the same manner as in Example 1.

The results are shown in Table 1.

(Examples 3 to 4) 4-methyl-1°2.3.6 used in Example 1
The same operation was carried out except that another acid anhydride was used instead of -titrahydrophthalic anhydride.

The results are shown in Table 1.

(Comparative Example 1) Epoxy resin before adding 4-methyl-1,2゜3.6-titrahydrophthalic anhydride and 2゜4.6-tris(dimethylaminomethyl)phenol in Example 1 The same operation as in Example 1 was performed except that the toner was prepared using the following.

The results are shown in Table 3.

(Comparative Example 2) 4-Methyl-1°2.3.6 used in Example 1
- Synthesize epoxy resin (I) by performing the same procedure except changing the amounts of titrahydrophthalic anhydride and 2,4.6-tris(N%N-dimethylaminomethyl)phenol to 1630 g and 16 g, respectively. And so.

However, the system gelled during the reaction, making synthesis impossible.

<Effects of the Invention> The epoxy resin for toner of the present invention is a resin obtained by modifying an epoxy resin with a specific amount of acid anhydride, and the toner for electrostatic image phenomenon of the present invention using this as a binder resin has the following properties:
It has the following effects.

■ It is possible to fix at low temperatures without causing offset during heat roll fixing.

■ No voids occur during heat fixing, and the appearance of printed matter is beautiful.

■ There is no adhesion of the transferred material to soft PVC.

Patent applicant: Mitsui Petrochemical Co., Ltd.

Claims (2)

[Claims] (1) It is characterized by containing an acid anhydride at a ratio of 0.02 to 0.2 mol per equivalent of epoxy group of the bisphenol type and/or hydrogenated bisphenol type epoxy resin. Epoxy resin for toner. (2) A resin containing an acid anhydride at a ratio of 0.02 to 0.2 mol per 1 equivalent of epoxy group of a bisphenol type and/or hydrogenated bisphenol type epoxy resin as a binder resin. A toner for developing an electrostatic image, comprising: