JPH056563B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a binder resin for a developer for developing electrostatic images in electrophotography, electrostatic recording, electrostatic printing, and the like.

[Conventional technology and problems]

Conventional electrophotographic methods include U.S. Patent No. 2297691;
No. 2,357,809, etc., an electrical charge is generated by uniformly charging a photoconductive insulating layer, then exposing the layer to light, and dissipating the charge on the exposed portions. A latent image is formed and then visualized by attaching a colored, electrically charged fine powder called toner to the latent image (development process), and the resulting visible image is transferred to a transfer material such as transfer paper. (transfer step), and then permanently fixed by heating, pressure or other suitable fixing method (fixing step).

As described above, the toner must have the functions required not only in the development process but also in each process such as the transfer process and the fixing process.

Generally, toner is subjected to mechanical frictional force due to shearing force and impact force during mechanical operation in a developing device, and deteriorates while copying several thousand to tens of thousands of copies.
To prevent this kind of toner deterioration, it is best to use a strong resin with a molecular weight that can withstand mechanical friction, but these resins generally have a high softening point and cannot be used in oven fixing, which is a non-contact fixing method. Radiant fixing using infrared rays has poor thermal efficiency, so fixing cannot be performed sufficiently, and contact fixing has good thermal efficiency, so even in the widely used heat roller fixing method, it is necessary to use a heat roller to achieve sufficient fixing. It becomes necessary to raise the temperature, which not only causes problems such as deterioration of the fixing device, curling of paper, and increased energy consumption, but also causes a significant drop in production efficiency when producing toner by pulverizing such resins. descend. Therefore, it is not possible to use a binder resin (binding resin) whose polymerization degree and even softening point are too high. On the other hand, in the heat roller fixing method, the heating roller surface and the toner image surface of the sheet to be fixed are in pressure contact, so the thermal efficiency is extremely high and it is widely used from low speeds to high speeds. When doing so, the toner adheres to the surface of the heating roller and is transferred to the subsequent transfer paper, etc.
So-called offset development is likely to occur. In order to prevent this development, the surface of the heating roller is treated with a material with excellent mold release properties such as fluorine-based resin, but a release agent such as silicone oil is also applied to the surface of the heating roller to completely prevent offset development. are doing.

However, the method of applying silicone oil is not preferable because it not only increases the size of the fixing device and increases the cost, but also makes it complicated, which tends to cause trouble.

Also, as described in Japanese Patent Publication No. 55-6895 and Japanese Patent Application Laid-open No. 56-98202, there is a method to improve offset development by widening the molecular weight distribution width of the binder resin, but the degree of polymerization of the resin increases and fixation becomes difficult. The temperature also needs to be high.

As a further improved method, Special Publication No. 57-493,
As described in JP-A-50-44836 and JP-A-57-37353, there is a method of improving offset development by making the resin asymmetrical and crosslinking, but the fixing point has not been improved.

Generally, the minimum fusing temperature is between cold offset and hot offset, so the usable temperature range is
It is between the minimum fixing temperature and hot offset, and by lowering the minimum fixing temperature as much as possible and raising the minimum hot offset temperature as much as possible, it is possible to lower the usable fixing temperature and expand the usable temperature range, which saves energy. , high-speed fixing, and prevents paper from curling. In addition, since double-sided copying can be performed without trouble, copying machines have become more intelligent, and the temperature control of the fixing device has become more accurate.
There are many advantages such as relaxing the tolerance range.

Therefore, resins and toners with good fixing properties and offset resistance are always desired.

In general, polyester resins and styrene resins are often used as resins, and it is desirable to use styrene resins economically, but styrene resins inherently have a high minimum fixing temperature, and the resin composition and wax Improvements made through the addition of compounds naturally had their limits.

The present invention has been made to meet these needs, and its purpose is to provide a developer that can prevent offset without applying an anti-offset liquid in a heat roller fixing system and that can be fixed at a lower fixing temperature. The purpose is to provide a binding resin.

Another object of the present invention is to provide a binder resin for a developer which can prevent offset without adding an offset preventive agent in a heat roller fixing system and which can be fixed at a lower fixing temperature.

Another object of the present invention is to provide a binder resin for a developer that has good fluidity, does not cause blocking, and has a long life (hard to deteriorate).

Another object of the present invention is to improve kneading properties during developer production.
An object of the present invention is to provide a binder resin for a developer with good pulverizability.

[Means for solving problems]

The present inventors have arrived at the present invention as a result of intensive research to achieve the above object.

That is, in the present invention, an α,β-unsaturated polymerizable monomer and a nitrile group-containing liquid polybutadiene are combined in a manner that the content of the nitrile group-containing liquid polybutadiene is 0.005.
The present invention relates to a method for producing a binding resin, which is characterized by carrying out a polymerization reaction so that the amount of the binding resin becomes 30% by weight.

As the nitrile group-containing liquid polybutadiene used in the present invention, acrylonitrile is 0.05 to 30%
It is copolymerized by weight%, the terminal is modified with a vinyl polymerizable functional group, and the viscosity is 100,000~
600000 (cps27°C) is preferable.

Typical α,β-unsaturated polymerizable monomers used in the present invention include, for example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2, Styrene or styrene derivatives such as 4-dimethylstyrene, p-chlorostyrene, vinylnaphthalene, ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, isobutylene, etc., such as vinyl chloride, vinyl bromide, vinyl fluoride , vinyl esters such as vinyl acetate, vinyl propionate, vinyl formate, vinyl caproate, etc., such as methyl acrylate,
Ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate,
Isobutyl acrylate, tert-butyl acrylate, amyl acrylate, cyclohexyl acrylate, n-octyl acrylate, isooctyl acrylate, decyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, methoxyethyl acrylate , 2-hydroxyethyl acrylate, glycidyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, amyl methacrylate, cyclohexyl methacrylate, n-octyl methacrylate, isooctyl methacrylate, decyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, methacrylic acid Ethylenic monocarboxylic acids and their esters such as stearyl, methoxyethyl methacrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, etc., such as acrylonitrile, methacrylonitrile , substituted ethylenic monocarboxylic acids such as acrylamide, etc., ethylenic dicarboxylic acids and substituted products thereof such as dimethyl maleate, vinyl ketones such as vinyl methyl ketone, vinyl ethers such as vinyl methyl ether, vinyl ethers such as vinylidene, etc. vinylidene halides such as chloride, e.g.
- N-vinyl compounds such as vinylpyrrole, N-vinylpyrrolidone, etc.

Preferably, among the components constituting the binding resin according to the present invention, styrene or a styrene derivative is used to form the main sliding case of the resin, adjustment of thermal properties such as softening point of the resin, determination of electric charge, and adjustment of the amount of charge. Ethylenic monocarboxylic acids and their esters are used.

The nitrile group-containing liquid polybutadiene that can be used in the present invention is produced by radical copolymerization of butadiene and acrylonitrile using a known hydroxyl group-containing polymerization initiator and a chain transfer agent, and then It can be obtained by introducing an acrylic vinyl group into. Preferred examples include, for example, liquid polybutadiene with 16.2% by weight of bound acrylonitrile, nearly 70% of the butadiene in the main chain having 1,4 bonds, and a viscosity of 280,000 cps/27°C, 3.8% of acrylyl vinyl groups, and bound acrylonitrile. is 16.5% by weight, and the viscosity is
Examples include liquid polybutadiene at 200,000 cps/27°C and 3.0% acrylic vinyl groups.

The nitrile group-containing liquid polybutadiene serves as a component that improves the minimum fixing temperature and offset resistance. The nitrile group in the nitrile group-containing liquid polybutadiene contributes to imparting chargeability and improving offset resistance. If the content of nitrile group-containing liquid polybutadiene in the binding resin is less than 0.005% by weight, fixing properties cannot be improved, and if it exceeds 30% by weight, the glass transition point of the binding resin will be lowered. Storage stability as a toner decreases. The method for producing the binding resin of the present invention is carried out by a well-known addition polymerization reaction using an initiator such as a peroxide or an azo compound.

The binding resin according to the present invention is used for electrophotography, and the coloring agents used together with the binding resin according to the present invention include carbon black, acetylene black, phthalocyanine blue, permanent brown FG, and brilliant first color. Lettu, Pigment Green B, Rhodamine-B
Base, Solvent Red 49, Solvent Red
146, Solvent Blue 35, and mixtures thereof, and are usually used in an amount of about 1 to 15 parts by weight per 100 parts by weight of the binding resin.

When making a magnetic toner using the binding resin according to the present invention, examples of the magnetic material include alloys or compounds containing elements exhibiting ferromagnetism such as ferrite and magnetite, and the magnetic material has an average particle size of 0.1
40-70% by weight in binder resin in the form of ~1μ fine powder
It can be used by dispersing the amount of .

Known property improving agents contained in toner include charge control agents, offset prevention agents, fluidizing agents, etc., but since the resin of the present invention has good properties by itself, these properties are not included when preparing the toner. Addition of a modifier becomes unnecessary, or even if added, only a small amount is required.

〔Example〕

Examples of the present invention will be described below, but the present invention is not limited to these examples. still,
All composition ratios shown in the examples are expressed in parts by weight.

Example 1 500 parts of xylene was placed in a reactor equipped with a stirring device, a nitrogen inlet tube, a thermometer, a reflux condenser tube, and a dropping funnel.
Liquid polybutadiene (acrylonitrile 16.2
20 parts by weight, viscosity 280000 (cps, 27℃), acrylic vinyl group 3.8%), and the temperature was 80℃.
Adjust to 810 parts of styrene, 170 parts of n-butyl acrylate and benzoyl peroxide under a nitrogen stream
20 parts of the mixture was polymerized dropwise over 4 hours. After aging at the same temperature for 10 hours after dropping, the temperature was gradually raised to 200°C while the pressure was reduced to 60mmHg, the xylene was distilled off, and the molten resin was taken out into a stainless steel vat, left to cool, and pulverized to form a powder. Resin (Koka type flow tester softening point 124.5℃, Tg62.7
°C) was obtained. This softening point was determined by heating a 1 cm ³ sample at a heating rate of 6°C/min using a Koka type flow tester (manufactured by Shimadzu Corporation) and using a plunger to
Apply a load of Kg/cm ² and push out a nozzle with a diameter of 1 mm and a length of 1 mm, thereby drawing a plunger drop-temperature curve of the flow tester,
When the height of the S-shaped curve is h, the temperature corresponding to h/2 is defined as the softening point.

After mixing 93 parts of the resin and 7 parts of carbon black (Regal 400R manufactured by Kabot Corporation) in a ball mill,
After coarsely pulverizing with a hammer mill, finely pulverizing with a jet mill, and classifying, a toner having an average particle size of 12.6 μm was obtained.
The obtained toner was mixed with carrier iron powder (manufactured by Nippon Tetsuko Co., Ltd.; EFV200/300), and the amount of charge was measured using a blow-off measuring device, and it was found to be -16 μc/g.

A developer was prepared by mixing 91 g of the toner with 1209 g of carrier iron powder, and a commercially available electrophotographic copying machine (the photoreceptor is amorphous selenium, the fixing roller has a diameter of 60 mm)
mm, rotation speed is 255 mm/sec, the heat roller temperature in the fixing device is variable and the oil application device is removed), and there was no background smudge, smearing, or missing black solid areas. A clear image was obtained.

When the fixing temperature was controlled between 140℃ and 220℃ and the image fixation and offset properties were evaluated, the result was 145.
It was sufficiently fixed at ℃, and no offset occurred. When images were printed up to 50,000 sheets, clear images were obtained with no background fogging or missing solid black areas.

The minimum fixing temperature here is 15mm x 7.5mm on the bottom.
A load of 500g was placed on a sand eraser, and the image fixed through the fixing machine was rubbed back and forth 5 times, and the optical reflection density was measured using a Macbeth reflection densitometer before and after rubbing, and the fixing rate was 70 as defined below. This refers to the temperature of the fixing roller when the temperature exceeds %.

Fixing rate = Image density after rubbing / Image density before rubbing Example 2 500 parts of xylene and liquid polybutadiene (containing 16.5% by weight of acrylonitrile, viscosity 200000 (cps, 27°C), acrylic) were placed in the reactor of Example 1. Add 10 parts of vinyl (3.0%) and adjust the temperature to 80℃. A mixed solution of 820 parts of styrene, 130 parts of 2-ethylhexyl acrylate, 40 parts of dimethylaminoethyl methacrylate and 10 parts of α,α'-azobisisobutyronitrile was dropwise polymerized over 4 hours under a nitrogen stream. After completion of dripping, mature at the same temperature for 10 hours.
While gradually increasing the temperature to 200°C, the pressure was reduced to 60mmHg, the xylene was distilled off, the molten resin was taken out into a stainless steel vat, allowed to cool, and pulverized.
Tg60.2℃) was obtained.

After mixing 93 parts of the resin and 7 parts of carbon black (Regal 400R manufactured by Kabot Co., Ltd.) in a ball mill,
The mixture was kneaded, crushed, and classified to obtain a toner with an average particle size of 13.0μ.

The amount of charge of the obtained toner was +20 μc/g.

91 g of the toner was mixed with 1209 g of carrier iron powder (manufactured by Nippon Tetsuko Co., Ltd.; EFV200/300) to prepare a developer, and a commercially available electrophotographic copying machine (the photoreceptor is an organic photoconductor, the rotation speed of the roller is 255 mm) /second, the temperature of the heat roller in the fixing device was made variable, and the oil application device was removed), and a clear image was obtained with no background smudges, smearing, or missing solid black areas. Ta. Adjust the fixing temperature of the fixing device.
When controlling the temperature between 140℃ and 220℃ and evaluating the fixation and offset properties of the image, the image was fixed at 150℃.
No offset occurred. After printing up to 30,000 images, clear images were obtained with no background fogging or missing solid black areas.

Comparative Example 1 Using the reactor of Example 1, a mixture of 830 parts of styrene, 170 parts of 2-ethylhexyl acrylate, and 15 parts of benzoyl peroxide was added dropwise to 500 parts of xylene over 4 hours at 80°C. Aged for 10 hours at temperature. Thereafter, toluene was distilled off using the method of Example 1, and a powdered resin (softening point: 130.5°C, Tg: 62.0°C using Koka flow tester) was obtained after extraction and pulverization. A toner (charge amount was -18 μc/g) was made using the resin in exactly the same manner as in Example 1, a developer was prepared, and an image was produced using the same evaluation machine as in Example 1. Clear images were obtained with no background smudges, smearing, or missing solid black areas. When the fixing temperature of the fixing device was controlled at 140 DEG C. to 220 DEG C. and the image fixability and offset properties were evaluated, the image was fixed at 175 DEG C., but offset occurred at all temperatures from 140 DEG C. to 220 DEG C.

Comparative Example 2 Using the reactor of Example 1, 850 parts of styrene and n-butyl acrylate were mixed in 500 parts of xylene at 80°C.
A mixed solution of 140 parts of divinylbenzene, 15 parts of divinylbenzene, and 15 parts of lauroyl peroxide was added dropwise over 4 hours, and after aging at the same temperature for 10 hours, the xylene was distilled off using the method of Example 1, extracted, and crushed to form a powder. A resin (Koka flow tester softening point: 131.0°C, Tg: 62.2°C) was obtained. A toner (charge amount was -18.5 μc/g) was prepared using the resin in exactly the same manner as in Example 1, prepared with a developer, and imaged using the same evaluation machine as in Example 1. Clear images were obtained with no background smudges, smearing, or missing solid black areas. When the fixing temperature of the fixing device was controlled and the image fixing and offset properties were evaluated, no offset occurred from 140°C to 220°C, but the fixing temperature was 195°C.
It was hot.

Claims (1)

[Claims] 1 Styrene or styrene derivatives, ethylenically unsaturated monoolefins, vinyl esters,
Ethylene monocarboxylic acids and their esters, ethylenic monocarboxylic acid substitutes, ethylenic dicarboxylic acids and their substitutes, vinyl ketones, vinyl ethers, vinylidene halides and N-
One or more α,β-unsaturated polymerizable monomers selected from the group consisting of vinyl compounds, butadiene, and acrylonitrile having an acrylonitrile content of 0.05 to 30% by weight,
A nitrile group-containing liquid polybutadiene whose end has a vinyl-polymerizable functional group and a viscosity of 100,000 to 600,000 (cps27°C) is mixed with a nitrile group-containing liquid polybutadiene having a content of 0.005 to 30.
% by weight.