JPH09166887A - Binder resin for toner and toner - Google Patents

Abstract

(57) [PROBLEMS] To provide a binder resin for a toner and a toner, which have excellent fixing strength in a low temperature range and excellent balance between fixing property and non-offset property. A toner composed of a styrene-based monomer unit and an acrylic-based monomer unit, and a styrene-acrylic-based copolymer containing 0.1 to 10% by weight of a 2-methacryloyloxyethylsuccinic acid unit as a copolymerization component. And a toner containing the styrene-acrylic copolymer as a main component of the binder resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a binder resin for a toner used for developing an electrostatic charge image or a magnetic latent image in an electrophotographic method, an electrostatic recording method, an electrostatic printing method and the like, and a toner. More specifically, the present invention relates to a toner binder resin and a toner capable of providing a toner having a good balance between fixing property and non-offset property.

[0002]

2. Description of the Related Art In a typical image forming process by an electrophotographic method or an electrostatic printing method, a photoconductive insulating layer is uniformly charged, the insulating layer is exposed, and then a charge on an exposed portion is obtained. To form an electric latent image by dissipating the toner, and a developing step of visualizing the latent image by adhering a finely charged toner to the latent image, and transferring the obtained visible image to a transfer material such as transfer paper. It comprises a transfer step of transferring and a fixing step of permanently fixing by heating or pressing.

Various performances are required for the toner and the binder resin for the toner used in the electrophotographic method or the electrostatic printing method in each of the above steps. For example, in the development process, the toner and the binder resin for the toner maintain a charge amount suitable for a copying machine without being affected by the surrounding environment such as temperature and humidity in order to attach the toner to the electric latent image. I have to do it. Also,
In the fixing step by the heat roller fixing method, the non-offset property that does not adhere to the heat roller and the fixability to paper must be good. Further, it is required to have a blocking resistance so that the toner does not block during storage in a copying machine.

Conventionally, binder resins for toners include:
Styrene-acrylic resins are frequently used, and linear type (non-crosslinked type) resins and crosslinked type resins are used. In the cross-linking type binder resin for toner,
As described in JP-B-51-23354, it has been attempted to broaden the molecular weight distribution by crosslinking a resin to improve the fixability and non-offset property as a toner. Further, in the linear type binder resin for toner, as described in JP-B-55-6895 and JP-B-63-32183, a high molecular weight polymer component and a low molecular weight polymer component are mixed. hand,
Attempts have been made to improve the fixing property and non-offset property of the toner by controlling the glass transition temperature and the molecular weight of both components and the molecular weight distribution (Mw / Mn) of the entire resin.

[0005]

However, in a toner using such a conventional linear type binder resin for a toner, the melt viscosity of the resin is lowered and the non-offset as a toner is attempted when the fixability is improved. As a result, it was difficult to balance the fixability and the non-offset property. In particular, there has been a problem that the fixing strength is insufficient in a region where the fixing temperature is low corresponding to the low temperature fixing property, which has been attracting attention in recent years. Therefore, an object of the present invention is to provide a toner binder resin and a toner which are excellent in fixing strength in a low temperature region and which are excellent in balance of low temperature fixing property and non-offset property as a toner.

[0006]

In view of such circumstances, the inventors of the present invention have made earnest studies on the resin for toner, and as a result, as a result, the resin for toner containing a styrene-acrylic copolymer as a main component was copolymerized. It has been found that by containing a specific amount of a specific monomer unit as a component, a toner resin having excellent fixing strength at low temperature and excellent balance between fixing property and non-offset property as a toner can be obtained. The invention has been reached. That is, the binder resin for a toner of the present invention is composed of a styrene-based monomer unit and an acrylic-based monomer unit and contains 2% as a copolymerization component.
-Methacryloyloxyethyl succinic acid unit 0.1 to
It is characterized by being composed of a styrene-acrylic copolymer containing 10% by weight. Further, the toner of the present invention is characterized by containing a styrene-acrylic copolymer containing 0.1 to 10% by weight of a 2-methacryloyloxyethyl succinic acid unit as a copolymerization component as a main component of a binder resin. It is what

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The styrene-acrylic copolymer used as the main component of the binder resin for toner of the present invention is
It is a styrene-acrylic copolymer composed of a styrene monomer and a copolymerizable acrylic monomer, and contains 0.1 to 10% by weight of a 2-methacryloyloxyethyl succinic acid unit as a copolymerization component. is important.

In the present invention, 2-methacryloyloxyethylsuccinic acid is used for improving the balance between the fixing property and the non-offset property of the toner and improving the fixing strength at low temperature. In the copolymer, 0.
It is contained in the range of 1 to 10% by weight. This has a 2-methacryloyloxyethyl succinic acid unit content of 0.1.
If it is less than 10% by weight, the effect of improving the balance between the fixing property and the non-offset property of the toner cannot be obtained. On the other hand, if it exceeds 10% by weight, the toner's charging characteristics are highly dependent on the humidity, and This is because the moisture resistance of is reduced. Preferably, the content of 2-methacryloyloxyethyl succinic acid unit is 0.5 to 5% by weight, more preferably 0.1.
It is in the range of 5 to 4% by weight.

In the present invention, the styrene-based monomer used for the polymerization of the styrene-acrylic copolymer is styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene. Styrene, p-
Ethylstyrene, 2,4-dimethylstyrene, pn-
Butylstyrene, p-tert-butylstyrene, p-
n-hexylstyrene, pn-octylstyrene, p
-N-nonyl styrene, pn-densyl styrene, p
-N-dodecyl styrene, p-phenyl styrene, 3,
4-dicyclosyl styrene etc. are mentioned, Especially, styrene is preferable. These styrene monomers can be used alone or in combination of two or more.

Further, copolymerizable acrylic monomers other than the above (meth) acrylic acid ester monomers include ethyl acrylate, methyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate. , 2-ethylhexyl acrylate, stearyl acrylate,
Acrylic esters such as methacrylic acid, ethyl methacrylic acid, methyl methacrylic acid, n-butyl methacrylic acid, isobutyl methacrylic acid, propyl methacrylic acid, 2-ethylhexyl methacrylic acid, stearyl methacrylic acid, etc. are mentioned. To be Further, unsaturated dicarboxylic acid diesters such as dimethyl maleate, diethyl maleate, butyl maleate, dimethyl fumarate, diethyl fumarate and dibutyl fumarate, unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid and cinnamic acid, maleic acid. Unsaturated dicarboxylic acids such as acids, fumaric acid, itaconic acid,
A carboxylic acid-containing vinyl monomer such as an unsaturated monocarboxylic acid monoester such as monomethyl maleate, monoethyl maleate, monobutyl maleate, monomethyl fumarate, monoethyl fumarate or monobutyl fumarate can also be used in combination.

The copolymerization ratio of these monomers is not particularly limited, but is preferably selected so that the glass transition temperature of the obtained binder resin for toner is in the range of 40 to 80 ° C. This is because when the glass transition temperature of the binder resin for toner is lower than 40 ° C., the blocking occurrence temperature of the toner is lowered, and the storage stability tends to be extremely lowered. Further, when the glass transition temperature of the binder resin for toner exceeds 80 ° C., the softening temperature of the toner becomes high and the fixability tends to be lowered. More preferably, it is in the range of 50 to 70 ° C. from the viewpoint of fixability as a toner. Furthermore, the styrene-acrylic copolymer of the present invention has a softening temperature of 100.
It is preferably in the range of ˜2000 ° C. This is because when the softening temperature is lower than 100 ° C., the non-offset property as a toner tends to decrease, and when the softening temperature exceeds 200 ° C., the fixing property as a toner tends to decrease, and preferably 120 Is in the range of 180 ° C.

Further, the styrene-acrylic copolymer is preferably composed of a high molecular weight copolymer and a low molecular weight copolymer. Specifically, the weight average molecular weight is 2
It is composed of a high molecular weight copolymer having a weight average molecular weight of 2,000 to 50,000 and a low molecular weight copolymer having a weight average molecular weight of 2,000 to 50,000, and the content of the high molecular weight copolymer is 20 to 70% by weight. What is the range of.
This is because the weight average molecular weight of the high molecular weight copolymer is 200,
If it is less than 000, the non-offset property as a toner tends to decrease, and if it exceeds 1,500,000, the fixability as a toner tends to decrease, and more preferably 200,000. ~ 700,000
And particularly preferably 220,000 to 50
It is in the range of 000. Further, if the weight average molecular weight of the low molecular weight copolymer is less than 2,000, the mechanical strength of the binder resin for toner is lowered, and the toner tends to be in an excessively pulverized state at the time of electrification, which tends to cause fog in the image. On the contrary, when it exceeds 50,000, the fixing property as a toner tends to be deteriorated, more preferably in the range of 6,000 to 30,000, particularly preferably 9,000 to 20, The range is 000. Further, if the amount of the high molecular weight copolymer is less than 20% by weight, the non-offset property as a toner tends to be poor, and conversely 70
This is because if the amount exceeds 5% by weight, the fixability as a toner tends to be poor, and the range is more preferably 25 to 50% by weight, and particularly preferably 30 to 40% by weight.

The polymerization of these polymerizable monomers can be carried out by a known polymerization method such as a suspension polymerization method, a solution polymerization method, an emulsion polymerization method or a bulk polymerization method, but there is no problem of odor due to residual solvent, and The suspension polymerization method is preferable from the viewpoints that the heat generation is easily controlled, the amount of the dispersant used is small, and the moisture resistance is not impaired. In particular, the obtained toner binder resin is preferably composed of a uniformly mixed high molecular weight polymer component and low molecular weight polymer component, and suspension polymerization of the high molecular weight polymer component is performed. It is preferable to carry out polymerization by a polymerization method such as a two-stage suspension polymerization method in which suspension polymerization of a low molecular weight polymer component is carried out in the presence of suspended particles of a high molecular weight polymer component. The method for producing the binder resin for toner of the present invention by the two-step suspension polymerization method will be described below.
This will be specifically described. Suspension polymerization of high molecular weight polymer components
It is not particularly limited and can be carried out according to a general suspension polymerization method, and together with the above-mentioned monomers, a dispersant, a polymerization initiator and a molecular weight modifier which are generally used in suspension polymerization. Etc. can be used.

As the polymerization initiator used for suspension polymerization of the high molecular weight polymer component, a compound having three or more t-butylperoxide groups in one molecule or a 10-hour half-life temperature of 90 to 140 ° C. It is possible to use a radical polymerization initiator having one functional group in one molecule. For example, as a compound having three or more t-butyl peroxide groups in one molecule, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane and the like can be mentioned. The 10-hour half-life temperature is 90-140.
Examples of the radical polymerization initiator having one functional group in one molecule at ° C include t-butyl peroxy laurate, t-butyl peroxy 3,5,5-trimethylhexanoate,
Cyclohexanone peroxide, t-butylperoxyisopropyl carbonate, t-butylperoxyacetate, t-butylperoxybenzoate, dicumyl peroxide, t-butylcumyl peroxide, diisopropylbenzene hydroperoxide, di-t-butylperoxide Oxide, p-methane hydroperoxide, 2
-(Carbamoylazo) isobutyronitrile, 2,2-
Organic peroxides such as azobis (2,4,4-trimethylpentane) and 2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile, and azo compounds. These polymerization initiators can be used alone or in combination of two or more. The amount of the polymerization initiator used may be a very small amount as compared with the amount of the polymerization initiator used in the conventional suspension polymerization, and 0.001 to 0.5 parts by weight based on 100 parts by weight of all the monomers. It is preferably used in the range of parts, and more preferably 0.002 to 0.05 parts by weight.

In the present invention, it is particularly preferable to use a compound having 3 or more t-butylperoxide groups in one molecule as a polymerization initiator. This is because the high molecular weight polymer component is 95 ° C. or higher, preferably 95 to 150.
At a high temperature of 100 ° C., more preferably 110 to 140 ° C., and polymerization is carried out by suspension polymerization using a compound having three or more t-butylperoxide groups in one molecule as a polymerization initiator, thereby obtaining a polymerization initiator. Is consumed efficiently,
This is because a high molecular weight polymer component having a high weight average molecular weight of 200,000 or more can be obtained in a short time of about 1 to 3 hours. Further, in the present invention, it is necessary to produce the high molecular weight polymer component by suspension polymerization at a polymerization temperature of 95 ° C. or higher. It has a polymerization temperature of 95
This is because when the temperature is lower than 0 ° C, the polymerization rate becomes slow and it takes a long time to obtain a polymer having a target molecular weight. In addition, the suspension polymerization of the high molecular weight polymer component is 0.5 to
It is preferable to carry out under a pressure of 7 kg / cm ² . The high molecular weight polymer component polymerized by suspension polymerization preferably has a weight average molecular weight (Mw) of 200,000 to 1,500,000.

Then, the low molecular weight copolymer is polymerized by suspension polymerization in the presence of the suspension particles of the suspension polymerized high molecular weight copolymer. The suspension polymerization is not particularly limited, and can be carried out according to a general suspension polymerization method. For example, when the polymerization reaction rate of a high molecular weight polymer becomes about 10 to 90%, a low molecular weight It is preferable to start the polymerization by dissolving and adding the polymerization initiator for the polymer to water or the monomer for the low molecular weight polymer. When the low molecular weight polymer monomer is added, the content of the low molecular weight polymer component in the obtained binder resin for toner is 30 to 8
It is preferable to add such an amount that the range is 0% by weight.

The polymerization initiator used for suspension polymerization of the low molecular weight polymer component is not particularly limited,
Usually used peroxides and azo compounds having radical polymerizability can be used. For example, di-t-butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, acetyl peroxide, isobutyryl peroxide Oxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, benzoyl peroxide, m-toluoyl peroxide, t-butylperoxyacetate, t-butylperoxide Oxyisobutyrate,
t-butyl peroxypiparate, t-butyl peroxy neodecanoate, cumyl peroxy neodecanoate, t-butyl peroxy 2-ethylhexanoate,
t-butyl peroxy 3,5,5-trimethylhexanoate, t-butyl peroxylylate, t-butyl peroxybenzoate, t-butyl peroxyisopropyl carbonate, azobisisobutyl nitrile, 2,
Examples thereof include 2-azobis- (2,4-dimethylvaleronitrile). Among them, octonyl peroxide, decanonyl, and the like, from the viewpoint of the persistence of the polymerization activity for the monomer and the completion of the polymerization in a relatively short time. Peroxide, lauroyl peroxide, benzoyl peroxide and m-trioil peroxide are preferred. These polymerization initiators can be used alone or in combination of two or more,
The monomer is preferably used in the range of 0.1 to 10 parts by weight, more preferably 0.5 to 100 parts by weight.
The range is 10 parts by weight. The low molecular weight polymer component polymerized by suspension polymerization has a weight average molecular weight of 2,000 to
It is preferably in the range of 50,000.

The suspension polymerization is preferably 1 for the monomers.
With about 10 times, more preferably about 2 to 4 times water, a dispersant, a polymerization initiator, and optionally a dispersion aid or a chain transfer agent are added, and the temperature is raised to a predetermined polymerization temperature. The heating is continued until the polymerization rate reaches a predetermined level. Examples of the dispersant used in the suspension polymerization include polyvinyl alcohol, an alkali metal salt of a homopolymer or copolymer of (meth) acrylic acid, carboxytyl cellulose, gelatin, starch, barium sulfate, calcium sulfate, calcium carbonate, Examples thereof include magnesium carbonate and calcium phosphate. Among them, polyvinyl alcohol is preferable, and particularly preferable is partially saponified polyvinyl alcohol having an acetic acid group and a hydroxyl group in a block manner. These dispersants are used in an amount of 0.0
It is preferable to use it in the range of 1 to 5 parts by weight. If the amount of the dispersant is less than 0.01 part by weight, the stability of the suspension polymerization is lowered, and the polymer tends to be solidified by aggregation of formed particles, and conversely, the amount exceeds 5 parts by weight. This is because the toner tends to have a lower environmental dependency, particularly the moisture resistance, and the content is more preferably in the range of 0.05 to 2 parts by weight. If necessary, a dispersing aid such as sodium chloride, potassium chloride, sodium sulfate or potassium sulfate can be used together with these dispersants. further,
In order to adjust the molecular weight, a chain transfer agent such as n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, 2-ethylhexyl thioglycolate, or α-methylstyrene dimer may be used, if necessary. .

The toner of the present invention comprises the above-mentioned binder resin as a main component and, in addition thereto, additives such as a colorant, a pigment, a charge control agent, an anti-offset agent, and magnetic powder as appropriate. , Binder resin 60 to 95% by weight
Use within a certain range. As the colorant, pigment, charge control agent, offset preventing agent, magnetic powder, those commonly used may be used, for example, carbon black, nigrosine dye, lamp black, Sudan black SM, navel yellow, mineral first yellow, resole. Coloring agents or pigments such as red and permanent orange 4R, nigrosine, alkyl group-containing azine dyes, basic dyes, monoazo dyes or their metal complexes, salicylic acid or its metal complexes, alkylsalicylic acid or its metal complexes, naphthoic acid or its Charge control agents such as metal complexes,
Offset preventing agents such as polyethylene, polypropylene and ethylene-polypropylene copolymer, and magnetic powders such as ferrite and magnetite can be used. The toner of the present invention is
For example, it is manufactured by the following method. The binder resin and various additives are mixed by a kneader such as a twin-screw extruder or a mixer at a temperature of 15 to 30 higher than the softening temperature of the binder resin.
After kneading at a temperature as high as about ℃, fine pulverization and classification are performed to obtain a toner. The obtained toner particles have an average particle size of 5 to 2
It is preferably about 0 μm, preferably about 8 to 15 μm, and the amount of fine particles having a particle size of 5 μm or less is preferably less than 3% by weight.

[0020]

The present invention will be specifically described below with reference to examples. In Examples, the glass transition temperature was determined by a DSC method (heating rate: 10 ° C./min) after the sample was heated to 100 ° C. and melt-quenched. As for the softening temperature, a flow tester (CFT-500 manufactured by Shimadzu Corporation) having a nozzle of 1 mmφ × 10 mm was used, and under the conditions of a load of 30 Kgf and a heating rate of 3 ° C./min, 1/2 of the sample amount flows out. The temperature is shown when

As for the non-offset fixing temperature range, the unfixed image obtained by using a copying machine (Panasonic Corporation FP-1570) is fixed at a fixing speed of 300 mm by using a fixing tester capable of freely changing the fixing temperature. A fixed image was obtained at 1 / sec. The obtained fixed image was rubbed with a sand eraser (JIS512) 9 times, and the image densities before and after the rubbing were measured with a Macbeth densitometer, and the lowest temperature at which the decrease in the image density was less than 20% was defined as the lower limit fixing temperature. Further, the unfixed image was passed through a fixing tester at a fixing speed of 100 mm / sec, and the state of contamination of the fixing roller by the toner was visually observed, and the temperature of the fixing roller at the start of contamination was defined as the upper limit fixing temperature. The image fogging is
The white portion of the fixed image obtained by the evaluation of the non-offset fixing temperature range was visually observed and evaluated. Moisture resistance is determined by the charge amount after the toner is left in an environment of a temperature of 30 ° C. and a humidity of 80% for about 20 hours and the charge amount after the toner is left in an environment of a temperature of 30 ° C. and a humidity of 80% for about 20 hours. It was measured and its environmental dependence was judged.

Example 1 A monomer mixture consisting of 76 parts by weight of styrene, 12 parts by weight of n-butyl acrylate and 2 parts by weight of 2-methacryloyloxyethyl succinic acid was added as a polymerization initiator to 2,2-.
Bis (4,4-di-t-butylperoxycyclohexyl) propane (Perkadox 12 manufactured by Kayaku Akzo Co., Ltd.)
0.005 parts by weight was dissolved and added to a mixture of 200 parts by weight of deionized water and 0.2 part by weight of partially saponified polyvinyl alcohol (Gosenol GH-23 manufactured by Nippon Synthetic Chemical Industry Co., Ltd.). And stir. Next, the temperature was raised to 130 ° C. and suspension polymerization of the high molecular weight polymer was performed for 1 hour. Furthermore, 40
6 parts by weight of benzoylperoxide and 1 part by weight of t-butylperoxybenzoate ("Per-Butyl Z" manufactured by NOF CORPORATION) were added to the dispersion liquid of the high molecular weight polymer cooled to 0 ° C, and the mixture was heated to 130 ° C. The temperature was raised and suspension polymerization of the low molecular weight polymer was carried out for 1 hour. Then, it was cooled to room temperature, sufficiently washed with water, dehydrated and dried to obtain a styrene-acrylic copolymer in which a high molecular weight polymer component and a low molecular weight polymer component were uniformly mixed. The obtained styrene-acrylic copolymer had a glass transition temperature of 50 ° C and a softening temperature of 118 ° C.

Obtained styrene-acrylic copolymer 9
3 parts by weight, carbon black (# 40 manufactured by Mitsubishi Kasei) 4
1 part by weight, a charge control agent for negative charge (“Bontron S-34” manufactured by Orient Chemical Industry Co., Ltd.) and 2 parts by weight of a polyolefin wax (660P manufactured by Sanyo Kasei Co., Ltd.) are mixed and melt-kneaded at 120 ° C. for 5 minutes. did. Then, it is crushed using a jet mill crusher and classified to have an average particle size of 13 μm.
Was obtained. The obtained toner had a non-offset fixing temperature range of 130 to 240 ° C. and was excellent in the balance between the fixability and the non-offset property. Further, there was no fog in the image and the moisture resistance was excellent.

Example 2 As Example 1 except that a monomer mixture consisting of 80.5 parts by weight of styrene, 16.5 parts by weight of 2-ethylhexyl acrylate and 3 parts by weight of 2-methacryloyloxyethyl succinic acid was used. A styrene-acrylic copolymer was obtained by the same method. The obtained styrene-acrylic copolymer had a glass transition temperature of 55 ° C and a softening temperature of 119 ° C. 93 parts by weight of the obtained styrene-acrylic copolymer, 4 parts by weight of carbon black (# 40 manufactured by Mitsubishi Kasei), 1 part by weight of a charge control agent for negative charging ("Bontron S-34" manufactured by Orient Chemical Industry Co., Ltd.) And 2 parts by weight of a polyolefin wax (660P manufactured by Sanyo Kasei Co., Ltd.),
The mixture was melt-kneaded at 120 ° C. for 5 minutes. Then, the toner was pulverized using a jet mill pulverizer and classified to obtain a toner having an average particle diameter of 13 μm. The obtained toner had a non-offset fixing temperature range of 130 to 240 ° C. and was excellent in the balance between the fixability and the non-offset property. Further, there was no fog in the image and the moisture resistance was excellent.

Example 3 Except that a monomer mixture consisting of 80 parts by weight of styrene, 19.5 parts by weight of n-butyl acrylate and 0.5 parts by weight of 2-methacryloyloxyethyl succinic acid is used.
A styrene-acrylic copolymer was obtained in the same manner as in Example 1. The obtained styrene-acrylic copolymer had a glass transition temperature of 55 ° C and a softening temperature of 122 ° C. 93 parts by weight of the obtained styrene-acrylic copolymer, 4 parts by weight of carbon black (# 40 manufactured by Mitsubishi Kasei Co., Ltd.), a charge control agent for negative charging ("Bontron S-" manufactured by Orient Chemical Industry Co., Ltd.).
34 ") and 1 part by weight and 2 parts by weight of a polyolefin wax (660P manufactured by Sanyo Kasei Co., Ltd.), and mixed at 120 ° C for 5
Melt kneading for a minute. Then, the toner was pulverized using a jet mill pulverizer and classified to obtain a toner having an average particle diameter of 13 μm.
The obtained toner has a non-offset fixing temperature range of 135 to
The temperature was 240 ° C., and the balance between fixing property and non-offset property was excellent. Further, there was no fog in the image and the moisture resistance was excellent.

Comparative Example 1 A styrene-acrylic copolymer was obtained in the same manner as in Example 1 except that 78 parts by weight of styrene and 12 parts by weight of n-butyl acrylate were used as a monomer mixture. The obtained styrene-acrylic copolymer has a glass transition temperature of 50.
The softening temperature was 110 ° C. 93 parts by weight of the obtained styrene-acrylic copolymer, 4 parts by weight of carbon black (# 40 manufactured by Mitsubishi Kasei), 1 part by weight of a charge control agent for negative charging ("Bontron S-34" manufactured by Orient Chemical Industry Co., Ltd.) And polyolefin wax (660 manufactured by Sanyo Kasei Co., Ltd.)
P) 2 parts by weight were blended and melt-kneaded at 120 ° C. for 5 minutes. Then, the toner was pulverized using a jet mill pulverizer and classified to obtain a toner having an average particle diameter of 13 μm. The obtained toner had a non-offset fixing temperature range of 150 to 190 ° C., and the balance between the fixability and the non-offset property was not satisfied. Further, there was no fog in the image, and the moisture resistance was excellent.

Comparative Example 2 Styrene was prepared in the same manner as in Example 1 except that a monomer mixture consisting of 79 parts by weight of styrene, 18.5 parts by weight of n-butyl acrylate and 2.5 parts by weight of methacrylic acid was used. -Acrylic copolymer was obtained. The obtained styrene-acrylic copolymer had a glass transition temperature of 56 ° C and a softening temperature of 123 ° C. 93 parts by weight of the obtained styrene-acrylic copolymer, carbon black (# 4 manufactured by Mitsubishi Kasei)
0) 4 parts by weight, 1 part by weight of a charge control agent for negative charging (“Bontron S-34” manufactured by Orient Chemical Industry Co., Ltd.) and 2 parts by weight of a polyolefin wax (660P manufactured by Sanyo Kasei Co., Ltd.) were mixed, and the mixture was added at 5 ° C. at 120 ° C. Melt kneading for a minute. Then, pulverize with a jet mill pulverizer, classify and average particle size 1
3 μm toner was obtained. The obtained toner had a non-offset fixing temperature range of 160 to 200 ° C., and the balance between the fixability and the non-offset property was not satisfied. Further, there was no fog in the image, and the moisture resistance was excellent.

[0028]

INDUSTRIAL APPLICABILITY The present invention is excellent in fixing strength in a low temperature region by using a styrene-acrylic copolymer which copolymerizes a specific amount of 2-methacryloyloxyethylsuccinic acid unit as a binder resin for toner. It is possible to provide a toner having an excellent balance of fixing property and non-offset property.

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

Claims (2)

[Claims] 1. A styrene-acrylic copolymer comprising a styrene-based monomer unit and an acrylic-based monomer unit and containing 0.1 to 10% by weight of 2-methacryloyloxyethylsuccinic acid unit as a copolymerization component. A binder resin for toner, which is characterized in that 2. A toner containing the styrene-acrylic copolymer according to claim 1 as a main component of a binder resin.