JPH02235069A - Production of toner for developing electrostatic charge image and binder resin for toner - Google Patents

Abstract

PURPOSE:To enhance the fixing characteristics and offset resistance of the toner and to decrease fogging by using a styrene copolymer having specific two peaks in a GPC chromatogram. CONSTITUTION:The styrene system vinyl copolymer (P) having the two peaks in the GPC echromatogram is incorporated into this toner. The component P having 1X10<3> to 5X10<4> weight average mol. wt. (-Mw) in the low mol. wt. region, with the min. value between the above-mentioned two peaks as a base point and having <=3.0 ratio of -Mw/number average mol. wt. (-Mn), 1X10<5> to 8X10<5> -Mw in the high mol. wt. region with the above-mentioned min. value as the base point, and <=4 ratio of -Wm/-Mn thereof is used. A copolymer of styrene and (meth)acrylate or the copolymer further contg. (meth)acrylic acid is preferably used for the component P.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a toner for an electrostatic developer for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing, etc., and a binder used in the toner. This invention relates to a method for producing resin.

[Prior art]

Electrophotography generally uses a photoconductive substance to form an electrostatic charge image on a photoreceptor by various means, develops this electrostatic charge image with toner, and then transfers it to a transfer material such as paper. After that, it is fixed on a transfer material such as υ paper using a heat roller constant fixing method. This fixing method uses heat and pressure, and is quick and has good thermal efficiency, resulting in excellent fixing efficiency. On the other hand, in the fixing method described above, the toner image is brought into direct contact with the surface of the heat roller, and the toner image is melted by heating and pressure and fixed onto paper, etc., so a part of the toner image adheres to the surface of the fixing roller. This transfer material then transfers again to the next transfer material, causing a so-called offset phenomenon, resulting in staining of the transfer material such as paper.

Generally, in the above fixing method, the lower the melt viscosity, that is, the molecular weight, of the binder resin, the better the fixing efficiency, and the higher the melt viscosity, that is, the molecular weight, the better the offset property. The combination of remer and high molecular weight polymer is widely used, and in particular, styrene-acrylic polymers whose molecular weight can be easily adjusted are often used. That is, for example, JP-A-50-134652, JP-A-50-133242
As seen in the publication, attempts have been made to simultaneously improve fixing properties and offset properties by using low molecular weight styrene-acrylic resins and high molecular weight styrene-acrylic resins as binder resins. However, with the rapid development of the information society in recent years, there is a need for faster recording copying and clearer images in fields such as electrophotography9, and the method described in the above-mentioned patent publication is considered insufficient. For example, Japanese Patent Application Publication No. 55
At present, improvements have been made by adding wax or the like, as seen in Publication No. 153944, and there is a strong demand for improvement in the fixing properties and offset properties of the binder resin body.

[Problem to be solved by the invention]

An object of the present invention is to provide a toner that has excellent fixing properties and anti-offset properties, and is less prone to excessive grinding and fogging.

Another object of the present invention is to provide a method for producing the above-mentioned binder resin economically and efficiently.

[Means to solve the problem]

That is, the present invention has two peaks in the GPC chromatogram, and the weight average molecular weight (hereinafter referred to as Mw) in the low molecular weight region is I
X10'~5x104, its weight average molecular weight/
The ratio of number average molecular weight (hereinafter referred to as Mu) is 3.0 or less, and the Mw of the high molecular weight region based on the minimum value is I X 105 to 8 X 105, and A toner for developing an electrostatic image using a styrene-based vinyl copolymer having a Mvr/Mn ratio (hereinafter Mw/Mn is referred to as dispersion ratio) of 4 or less, and a part of a sterene-based vinyl copolymer-forming monomer. Or, using 0 to 50 parts by weight of the solvent to 100 parts by weight of the total amount, the polymerization rate is 10 to 7.
After thermal polymerization to a temperature of 0,000 yen, a mixture of 0 to 60 parts by weight of the remaining amount of the styrenic vinyl copolymer-forming heptomer and 0 to 640 parts by weight of a solvent and part or all of the initiator are added dropwise. The present invention relates to a method for producing the above-mentioned styrene-based vinyl copolymer for use in toners for developing silent charge images, which is obtained by solution polymerization.

In the present invention, the low molecular weight region based on the minimum value in the above GPC chromatogram of the mestele/vinyl copolymer has the effect of lowering the fixing temperature when toner development is fixed to a transfer material with a heat roll. The lower the Mw, the better the effect, but simply lowering the Mw will cause the toner to thermally agglomerate due to the friction between the toner and the magnetic powder when mixed with magnetic powder, etc. In addition, the toner may be over-pulverized, making it impossible to obtain high-quality images.

Therefore, by setting the dispersion ratio in the low molecular weight region to 'fc3 or less, it is possible to obtain a toner binder resin that has excellent fixing properties, thermal aggregation properties, and excessive pulverization properties.

In addition, the high molecular weight region based on the minimum value of the styrene-based vinyl copolymer of the present invention has the effect of preventing the offset phenomenon, and the effect becomes larger as the Mw increases, but it is simply a matter of increasing the Mw. Increasing the value increases the fixing temperature, and
Is that binder resin car? When melt-kneading the toner and crushing it to form a toner, it becomes difficult to crush it, making it impossible to produce toner economically. As a result, by minimizing the distribution on the polymer side in the high molecular weight region and reducing the dispersion to 4 or less, we have created a toner powder with low fixing temperature, high offset prevention effect, and high toner productivity. A coated resin is obtained.

Further, the area ratio of the low molecular weight region and the high molecular weight region based on the minimum value in the GPC chromatogram of the styrene-based vinyl copolymer of the present invention is (90 to 10): (10 to 90).
is preferable, and within this area ratio range, low-temperature fixing or offset resistance is excellent, and a good copy image can be obtained.

In addition, the two peaks in the GPC chromatogram of the styrene-based vinyl copolymer in the present invention refer to the large peaks in the GPC chromatogram, and the low molecular weight region based on the minimum value between the two peaks is the , refers to the range of low molecular weight from the point of such a minimum value, and furthermore, the high molecular weight region based on the pole/J% value between the two nuclear peaks refers to the range of high molecular weight from the point of such minimum value. say.

In addition, the styrenic vinyl copolymer in the present invention is one in which styrene is the main component and other vinyl monomers are copolymerized, and the other vinyl monomers include, for example, methyl acrylate, acrylic Ethyl acrylate, probyl acrylate, butyl acrylate, octyl acrylate, cyclohexyl acrylate, lauryl acrylate, stearyl acrylate, penzyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate, hydroxyethyl acrylate, hydroxybutyl acrylate Acrylic esters such as methyl methacrylate, ethyl methacrylate, globyl methacrylate, butyl methacrylate, octyl methacrylate, lauryl methacrylate, stearyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, furfuryl methacrylate, tetrahydro methacrylate Furfuryl, methacrylic acid esters such as hydroxyethyl methacrylate, hydroxyprobyl methacrylate, hydroxypter methacrylate, vinyltoluene, α
・Aromatic vinyl polymers such as methylstyrene and chlorsterene, unsaturated dibasic acid dialkyl esters such as diptyl maleate, dioctyl maleate, dibutyl fumarate, and dioctyl fumarate, vinyl esters such as vinyl acetate and vinyl propionate. Nitrogen-containing vinyl monomers such as acrylonitrile and methacrylonitrile, unsaturated carbonic acids such as acrylic acid, methacrylic acid, and cinnamic acid, unsaturated dicargenic acids such as maleic acid, maleic anhydride, fumaric acid, and itaconic acid. , monomethyl maleate, monoethyl maleate, monobutyl maleate, monooctyl maleate, monomethyl fumarate, monoethyl fumarate, monoptyl heptamarate, monooctyl fumarate, and other unsaturated dicarpyl monoesters. The ratio of styrene to other vinyl monomers is preferably 50% or more for styrene by weight, and the other vinyl monomers are preferably acrylic esters and/or methacrylic esters. Further, in the present invention, it is possible to provide a binder resin having an anti-offset effect by the above-mentioned means, but in order to further improve this effect, as a result of intensive research by the present inventors, styrene Copolymerization monomer of vinyl copolymer! By copolymerizing an addition polymerizable monomer containing a carboxyl group, a synergistic effect is exhibited, and the offset prevention effect is further improved. However, this is probably because the cargelyl group has a high hydrophilicity with water, but when a large amount of cargelyl group-containing monomer is copolymerized, the hygroscopicity of the toner, which is a fine powder, increases, and the interaction between the toner and magnetic powder, etc. Frictional charging power decreases, making it impossible to obtain a good copy image. In particular, in the GPC chromatogram of a styrene-based vinyl copolymer, when a large amount of calgexyl group-containing monomer is present as a polymer component constituting a low molecular weight region based on the minimum value, the amount of moisture absorbed increases, which is thought to be due to a molecular weight effect. There is a tendency for the number of copies to increase dramatically and many copy defects to occur. This point can be solved by adjusting the carboxyl group content of the 2-limer in the high molecular weight region to an acid value of 10 or less, and by setting the acid value in the low molecular weight region to 1/5 or less of the acid value in the high molecular weight region. It has been found that a binder resin with excellent offset effect and low hygroscopicity can be obtained, and improvements have been made.

Furthermore, when addition-polymerizing monomers, it is impossible to obtain a monodisperse polymer with a dispersion ratio of 1, and it is a difficult task to bring the dispersion ratio close to 1, especially in copolymerization systems. The trend is significant. Also, generally speaking, the larger the Mw, the worse the tendency.

This point can be seen, for example, in the embodiment of Japanese Patent Application Laid-Open No. 134652/1983. In the present invention, the GPC of the present invention
The high molecular weight region based on the minimum value in the chromatogram is polymerized to a certain polymerization rate by thermal polymerization without using a radical initiator, and then the polymer, monomer and/or
Alternatively, a mixture of a solvent and part or all of an initiator is added dropwise to polymerize a polymer in a low molecular weight region by a solution polymerization method, and the dispersion ratio of the low molecular weight region and the high molecular weight region is reduced by removing the solvent. It is possible to obtain a styrene-based vinyl copolymer binder resin which exhibits a sharp distribution and which is homogeneously mixed with the toner and has excellent toner properties.

Although the above-mentioned manufacturing method is the most economical and can yield resin of good quality, the present invention is not limited to this manufacturing method only, and can be applied to ordinary polymerization methods, such as solution polymerization and suspension polymerization. Polymerization may be carried out by any of legal, emulsion polymerization, bulk polymerization, radical polymerization, ionic polymerization, and thermal polymerization, or by a combination of these methods. They may be separately polymerized and then blended to form a toner, or the separately polymerized low-molecular weight substance and high-molecular weight substance may be dissolved by some method, for example, after homogeneously dissolving both in a solvent,
May be used in toner after removing solvent b. In addition, in the present invention, when producing the above-mentioned styrenic vinyl copolymer, chain transfer agents such as mercabutanes such as n-dodecylmercagutan and n-tridecylmercabutane, and polymerization inhibitors are used to adjust the molecular weight. and molecular weight modifiers, such as t-butylphenol, t-7'' tylcatechol, hydroquinones, and addition-polymerizable monomers with high chain transfer properties, such as α-
You can also use methylstyrene, vinyltoluene, etc.
In addition, for radical polymerization, azos-based initiators such as azobis-2,2'-isobutyronitrile, 2,2'-azobis(2,4-dimethylpaleronitrile), pezoylnoxide, lauroyl z'? -oxide, organic peroxides such as t-butylperoxyhydroterephthalate, etc., may be used alone or in combination, and the invention is not restricted by them.

Next, a method for manufacturing a toner and a toner formulation using the above-mentioned binder resin will be described.

First, the binder resin according to the present invention is crushed, and then mixed with Carne Black, a penzidine-based yellow organic pigment, such as Pigment Yellow, and a magenta-colored organic pigment, such as xanthene-based Bigme Red 81, and quinacridone-based 2,9- Dimethylquinacridone, phthalocyanine-based true color organic pigment,
For example, G. I. Pigment Pull-15, C. I. Solvent Blue 70, oil-soluble dyes such as C.I. I. Solvent Red 24, C. I. Dyeing such as Norpent Plue 7. Pigments, nigrosine to adjust the friction band properties as necessary, chromium-containing dyes, low molecular weight polyolefins to help prevent offset, aliphatic metal salts, silica, and in the case of one-component toners, magnetic iron oxide, etc. The toner is obtained by mixing, premixing, melting and blending using an extruder, pressurized seconder, etc.), and then pulverizing and classifying the toner); however, the present invention is not limited to the method of blending and manufacturing such toner.

The acid value in the present invention is KOH-m97J, and
M! The maximum value and minimum value of the dispersion ratio, the area ratio between the low molecular region and the high molecular region, etc. were determined by the GPC method, and the apparatus and measurement conditions were as follows.

Equipment LC-0 8 type column A-806+A-805+A-804+A-803 manufactured by Nippon Analytical Industry (Ten)
+A-802 Solvent THF Discharge rate 1.0 g/min Sample 0.1 THF 10k! g, measured at a heating rate of 6° C./min.

〔Example〕

Next, the present invention will be explained in detail by giving production examples, examples, and comparative examples. In each example, unless otherwise specified, the number of parts indicated means parts by weight.

(Production Example-1) 80 parts of styrene, 13 parts of n-butyl acrylate, 6.7 parts of methyl methacrylate, and 0.3 parts of methacrylic acid were placed in a flask equipped with a condenser, N2 gas inlet tube, and stirrer, and heated at 110°C to 120°C under N2 gas flow. Polymerization was carried out to a polymerization rate of 50%, and 50 parts of xylene was added to the obtained polymerization product and cooled. Next, 4 parts of azopisisobutylonitrile were added to obtain a dissolved mixture. Next, put 70 parts of xylol into a flask equipped with a condenser, N2 gas inlet pipe, and stirrer, and
The temperature was raised to 5°C and the mixture (
4) was added dropwise, and after completion of the dropwise addition, polymerization was further carried out at 135° C. for 10 hours, followed by distillation under reduced pressure to obtain a solid styrene-based vinyl copolymer.

(!! Preparation Example-2) In a flask equipped with a condenser, an N2 gas inlet pipe, and a stirrer, 71 parts of styrene, 20 parts of n-butyl acrylate, 9 parts of methyl methacrylate, and 0.0 parts of penzoylno I-oxide were placed.
1 part, 140 parts of ion-exchanged water, and 0.5 part of polyvinyl alcohol were polymerized under a stream of N2 gas with stirring at 80"C for 20 hours and at 95°C for 5 hours, followed by washing with water and drying. ) was obtained.Next, 100 parts of xylene was charged into the same flask as above, and after stirring, 135 parts of xylol was obtained.
The temperature was raised to ℃, and a mixed solution of 85 parts of styrene, 8 parts of n-butyl acrylate, 7 parts of methyl methacrylate, and 6 parts of penzoyl peroxide was added dropwise over a period of 5 hours. (B) was obtained. Next, 50 parts of polymer solution, part of polymer (B) Zoo,
50 parts of xylene was mixed and dissolved and distilled under reduced pressure to obtain a sterene-based vinyl copolymer.

Next, according to Production Examples 1 and 2, the conditions such as monomer composition, radical initiator type and concentration, polymerization temperature, and amount of solvent added were changed to produce Production Examples 3 to 5 listed in Table-1, and Table-2. Comparative Production Examples 1 to 6 described in .

In addition, in the table, low molecular area Mw, dispersion ratio, high molecular area Mw
, dispersion ratio indicates the GPC measurement value of the low molecular region and high molecular region based on the minimum value in the GPC chromatogram. The same applies to Table 2 below.

/ / Table 3 shows the results for the low molecular region and high molecular region based on the minimum value obtained by GPC and chromatogram measurements of the styrene-based vinyl copolymers of Production Examples 1 to 5 and Comparative Examples 1 to 6.
Shown below.

For reference, a chart of the GPC chromatogram of Production Example 3 is shown in FIG.

Examples 1 to 5, Comparative Examples 1 to 6 Using each of the styrenic copolymers of Production Examples 1 to 5 and Comparative Production Examples 1 to 6 as a binder resin for toner, toners were prototyped by the method shown below, and a copy test was conducted. went. Binder resin 100
5 parts, carbon plaque (Mitsubishi Kasei MA-11),
Charge control agent (Orient Chemical Bontron E-81) 1
．． 5 parts of polypropylene wax (Viscol 550P manufactured by Sanyo Chemical Co., Ltd.) were mixed in a sous/4' mixer, then melted and kneaded in a pressure kneader, cooled, and pulverized in a jet mill. , classified 5-15μm, average particle size 1
A toner of 2 μm was obtained. A developer was prepared by mixing 7 parts of the obtained toner with 93 parts of iron powder carrier, and an image was produced using a commercially available electrophotographic copying machine. A fixing test was conducted using a roll made of silicone rubber. Also, temperature 2
30,000 copies were made continuously under conditions of 0°C and humidity of 50 m, and at the same time observations were made for background stains, etc.;
5,000 copies were made under the same conditions and the state of the copies was observed. The results are shown in Table 4.

! [Effects of the Invention] By using the toner binder resin of the present invention, a toner having excellent low-temperature fixability, high-temperature offset resistance, crushability, and all-season continuous copying properties can be obtained.

[Brief explanation of drawings]

Figure 1 shows the styrenic vinyl copolymer (D
This is a chart of a GPC chromatogram, where A is a low molecular weight region and B is a high molecular weight region. Burialist

Claims (5)

[Claims] (1) In a GPC chromatogram, there are two peaks, and the weight average molecular weight in the low molecular weight region (hereinafter referred to as @M@w) is 1×1 based on the minimum value between the two peaks.
0^3 to 5x10^4, the ratio of weight average molecular weight/number average molecular weight (hereinafter referred to as @M@n) is 3.0 or less, and the high molecular weight region is based on the minimum value. @M@w
is 1×10^5 to 8×10^5, and that @M@w/@M
A toner for developing an electrostatic image using a styrene-based vinyl copolymer having an @n ratio of 4 or less. (2) The toner for developing electrostatic images according to claim 1, wherein the styrenic vinyl copolymer comprises styrene and an acrylic ester and/or a methacrylic ester. (3) The styrenic vinyl copolymer is composed of styrene, methacrylic acid and/or acrylic acid, and methacrylic acid ester and/or acrylic acid ester, and its high molecular weight region @M@w is 1×10^ 5~8×10^5, @
M@w/@M@n is 4 or less, acid value is 10 or less, and @M@w in the low molecular weight region is 1 x 10^3 to 5 x 10^
4. The toner for developing electrostatic images according to claim 1, which has an acid value of 1/5 or less of that of the high molecular weight region. (4) @M@w in the low molecular weight region is 1 x 10^3 to 5 x 1
0^3, and the molecular weight range of the region is 1 x 10^3 to 5 x
2. The toner for developing an electrostatic image according to claim 1, which has a GPC chromatogram peak at 10^3, and @M@w/@M@n of the entire styrene-based vinyl copolymer is 40 or more. (5) Forming a styrenic vinyl copolymer after thermally polymerizing to a polymerization rate of 10 to 70% using 0 to 50 parts by weight of a solvent to 100 parts by weight of one or all of the monomers, forming a styrenic vinyl copolymer. Claim 1 or 4, characterized in that solution polymerization is carried out by dropping a mixture of 0 to 60 parts by weight of the remaining monomer and 0 to 640 parts by weight of a solvent and part or all of the initiator. A method for producing a styrenic vinyl copolymer as described in .