JPH01222268A - Toner binder - Google Patents

Abstract

PURPOSE:To obtain an image contg. no fog by using a toner binder consisting of a copolymer having at least two peaks in a mol.wt. distribution curve obtd. by the gel permeation chromatography (GPC) and contg. <=30mol.% amino group-contg. monomer in a copolymer. CONSTITUTION:The title toner binder comprises a copolymer consisting of a carboxylic acid salt, a salt of an amino group-contg. monomer and a vinyl monomer, wherein the copolymer has at least two peaks in a molecular weight distribution curve obtd. by the GPC and a proportion of the amino group-contg. monomer in the copolymer is <=30mol.%. Suitable amino group-contg. monomer is an amino group-contg. vinyl compd., amino group-contg. (meth)acryloyl compd. Thus, a toner binder generating no fog and preventing deterioration of thermal characteristics of toner, is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a toner binder. More specifically, the present invention relates to a binder for positively chargeable toner.

[Prior Art] In electrophotography, an electrostatic latent image formed on a photoreceptor is visualized using toner. Conventionally, inorganic Se compounds have been used as photoreceptors, but they are expensive and have pollution problems, so in recent years organic photoreceptors (OPC) have been used.
It is starting to change. Se-based photoreceptors are positively charged and therefore require a negatively charged toner, whereas OPC is negatively charged and therefore require a positively charged toner.

In order to obtain a positively chargeable toner, a method of adding a charge control agent such as a dye such as GLOCK or a polymer having an amino group (e.g., Japanese Patent Application Laid-open No. 102633/1989) is also used. A method using a binder without groups is known.

[Problems to be solved by the invention] However, with the I-color obtained by the former method, fogging on the developing surface (a phenomenon in which an image containing a mixture of opposite images appears) is unavoidable; Fog and deterioration of the thermal properties of the toner are unavoidable.

[Means for Solving the Problems] The present inventors have conducted intensive studies to develop a binder for positively chargeable toner that does not cause fogging, and have arrived at the following invention. That is, the present invention is a copolymer consisting of a salt of a carboxylic acid and an amino group-containing monomer, and a vinyl monomer, and the polymer has a molecular weight distribution determined by gel permeation chromatography (hereinafter abbreviated as GPC). The binder for a positively chargeable toner is characterized in that it has two or more peaks in the figure, and the amount of the amino group-containing monomer in the copolymer is 30 mol% or less.

The amino group-containing monomer used in the copolymer refers to vinyl compounds and amino compounds having an amino group. This expression will be used below. ) The car is broken.

Examples of the former include vinylpyridine and vinylimidacilline, and examples of the latter include compounds represented by the following general formula (1).

[In the formula, R1 is hydrogen or an alkyl group having 1 to 6 carbon atoms. R2 and R3 are hydrogen, an alkyl group having 1 to 6 carbon atoms, or an aryl group. R1, R2 and R3 may be the same or different. Further, R2 and R3 may be optionally connected to each other to form a 5- or 6-membered ring including the nitrogen atom shown in the above general formula, optionally via an oxygen atom or a nitrogen atom. A is an alkylene group having 1 to 4 carbon atoms. X is -NH- or 10-. In the general formula (1), R1, R2, and R3 each have 1 to 6 carbon atoms.
Examples of the alkyl group include methyl, ethyl, and propyl groups. An example of the aryl group for R2 and R3 is a phenyl group. R2 and R3 may optionally be connected to each other to form a 5- or 6-membered ring containing the nitrogen atom shown in general formula (1) [for example -(CH2) n
- through a group in which n is 4 or 5], or this ring may be formed through a new heteroatom such as a nitrogen atom or an oxygen atom. Examples of these include piperidino group, morpholino group,
Examples include piperazino group and pyrrolidino group. Preferably, R1 is hydrogen or a methyl group, R2, R3
are methyl and ethyl groups. In reality, it is difficult to produce compounds in which R1, R2, and R3 have more than 6 carbon atoms.

As an alkylene group having 1 to 4 carbon atoms, an ethylene group,
I.rimethylene group and propylene group are mentioned. Preferably it is a trimethylene group. -X- is preferably -
It is NH-.

Specific examples of the amino group-containing monomer represented by general formula (1) include N,N-dimethylaminopropyl (meth)acrylamide, N,N-diethylaminopropyl (meth)acrylamide, and N,N-dimethylaminoethyl ( Meta)
Examples include acrylate, morpholinoethyl (meth)acrylate, and the like.

Preferred is N,N-diethylaminopropyl methacrylamide.

Examples of the carboxylic acid (containing an M anhydride group) include those that have copolymerizability with vinyl monomers, those that do not, and mixtures thereof. Examples of the former include unsaturated mono- or polycarboxylic acids [(meth)acrylic acid, ethacrylic acid, crotonic acid, sorbic acid, maleic acid, itaconic acid, cinnamic acid, etc.] their anhydrides (such as maleic anhydride), Partial esters thereof (such as maleic acid monomethyl ester) are included. Preferred are acrylic acid and methacrylic acid. Examples of the latter include aliphatic monocarboxylic acids having 10 or more carbon atoms (lauric acid, myristic acid, palmitic acid, stearic acid, etc.) and aromatic monocarboxylic acids (benzoic acid, etc.), preferably stearic acid and benzoic acid. It is an acid.

Examples of vinyl monomers include aromatic vinyl hydrocarbons, (meth)acrylic monomers, and other monomers.

Examples of the aromatic vinyl hydrocarbon include styrene or its substituted substances, such as styrene, alkyl-substituted styrene (α-methylstyrene, p-methylstyrene, etc.), halogen-substituted styrene (chlorostyrene, etc.), and the like.

Examples of (meth)acrylic monomers include (meth)acrylate [(,1-C18 alkyl (meth)acrylate (methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate) , lauryl (meth)acrylate, stearyl (meth)acrylate, etc.), hydroxyl group-containing (meth)acrylates (hydroxyethyl (meth)acrylate, etc.), and nitrile group-containing monomers ((meth)acrylonitrile, etc.).

Other monomers include vinyl esters (eg, vinyl acetate, vinyl propionate, etc.) and aliphatic vinyl hydrocarbons (eg, butadiene, etc.).

In order to obtain higher molecular weight polymers during polymerization, polyfunctional monomers having at least two polymerizable double bonds [e.g. di- or polyvinyl compounds (divinylbenzene, divinyltoluene, ethylene glycol diacrylate,
1,6-hexanediol diacrylate)] can be added.

Preferred are divinylbenzene and 1,6-hexanediol diacrylate.

Among these, aromatic vinyl hydrocarbons and (meth)acrylates are preferred, and particularly preferred are styrene, alkyl (meth)acrylates of 01 to C1B, and mixtures of two or more thereof.

The amount of each monomer based on the number of moles in the copolymer is as follows. The amount of amino group-containing monomer is usually 30
It is less than mol wood, preferably 0.5 to 10%. 0.5
If it is less than 30%, the positive chargeability of the toner will be insufficient;
%, the environmental dependence of the toner becomes insufficient. The amount of carboxylic acid is usually 30 mol% or less, preferably 0.1 to
It is 10%. If it is less than 0.1%, fogging will occur on the developed surface of the toner, and if it exceeds 30%, the positive chargeability of the toner will be insufficient.

The amount of vinyl monomer is usually 60 mol% or more, preferably 80 mol% or more. If it is less than 60 mol%, the environmental dependence when used as a toner becomes insufficient.

The composition of the monomer is as follows.

The amount of aromatic vinyl hydrocarbon is usually 50 to 90 mol χ, preferably 60 to 85 mol % based on the total amount of vinyl monomers. Similarly, (meth)acrylic monomers are usually 50 to 1
0 mol%, preferably 40 to 15 mol%.

If the amount of aromatic vinyl hydrocarbon exceeds 90 mol% and the amount of (meth)acrylic monomer is less than 10 mol%, the minimum fixing temperature (hereinafter abbreviated as MF) of the toner becomes high; If it is less than 50 mol %, the temperature at which the toner causes offset to the heat roll (hereinafter abbreviated as HO) will be low and the blocking property of the toner will be poor.

In addition, the polyfunctional monomer is usually 3 mol% or less, preferably 1
It is less than mol%. If the amount of polyfunctional monomer exceeds 3 mol %, gelation occurs during polymerization.

Other monomers such as vinyl esters and aliphatic hydrocarbon monomers are generally at most 10 mol%, preferably at most 5 mol%.

In the copolymer, the quotient obtained by dividing the number of moles of the carboxylic acid or carboxyl group-containing monomer by the number of moles of the amino group-containing monomer is usually 1 or less, preferably 0.2 to 0.8.

If this value exceeds 1, the positive chargeability of the toner will be insufficient.

As an example of a copolymer using a carboxylic acid having copolymerizability, N,N-dimethylaminopropylmethacrylamide (5.9 mol)-methacrylic acid (4.5 mol)-butyl acrylate) (14, 6 mol)-styrene (75
,0 mol) copolymer, N,N-dimethylaminopropylmethacrylamide (1,4 mol)-acrylic acid (0,
6 mol) -butyl methacrylate (24゜1 mol) -
Styrene (73,9 mol) copolymer and morpholinoethyl methacrylate (4,5 mol)-maleic anhydride (0.9 mol)-methyl methacrylate) (11,2
mol)-2-ethylhexyl acrylate (5,6 mol)-styrene (77,8 mol) copolymer.

As an example of a copolymer using a carboxylic acid that does not have copolymerizability, N,N-dimethylaminopropylmethacrylamide (1.6 mol)-butyl methacrylate (24,
0 mol)-benzoic acid (0.9 mol) salt of styrene (73.5 mol) copolymer and N,N-methylaminopropylmethacrylamide (5.9 mol)-butylacryle-J-(14.6 mol) )-styrene (75.0 mol) copolymer stearic acid (4.5 mol) salt.

The carboxylic acid salt of the amino group-containing monomer may be obtained by polymerizing the amino group-containing monomer and then turning it into a salt, or by polymerizing the salt of the amino group-containing monomer.

The copolymer can be obtained by polymerization using a radical initiator. Polymerization is possible in solution, emulsion, and suspension systems, but
Solution polymerization is preferred. Solvents for solution polymerization include aromatic hydrocarbon solvents (toluene, xylene, etc.), chlorine solvents (chloroform, carbon tetrachloride, ethylene dichloride, ethylene tetrachloride, etc.), and mixed solvents of two or more of these solvents. .

The amount of solvent used is usually 1000% based on the total weight of monomers.
% or less, preferably 30 to 400%. If the amount of solvent used exceeds 1,000%, production efficiency will decrease.

In addition, a polymerization initiator is usually used for polymerization, and these polymerization initiators include azo initiators (azobisisobutyronitrile, azobisisovaleronitrile, etc.), peroxide initiators (benzoyl peroxide, lauroyl peroxide, g-tert, -butyl peroxide, te
rt, -butylcumyl peroxide, dicumyl peroxide, tert, -butylperoxybenzoate, 1,1-bis(tert, -butylperoxy)
3,3,5-trimethylcyclohexane, etc.). The polymerization reaction is usually carried out in an atmosphere of an inert gas such as nitrogen. The polymerization temperature is usually 50 to 200°C, preferably 70 to 180°C. If the polymerization temperature is lower than 50°C, the reaction will take a long time and is not practical; if it exceeds 200°C, the polymer may decompose. The reaction time depends on other conditions, but is usually 1 to 50 hours, preferably 2 to 1 hour.
It is 0 hours. It is difficult to control the reaction under conditions where the reaction time is kept within 1 hour, and if it exceeds 50 hours it is economically disadvantageous. The solvent used during polymerization is removed after repulsion. Solvent removal is performed under normal pressure or reduced pressure.

The molecular weight of the polymer can be adjusted by adjusting the amount of catalyst, polymerization temperature, monomer concentration, and chain transfer agent.

The peak molecular weight of at least one GPC peak of the copolymer is usually 103 to 8X10', preferably 2X10'.
It is 3 to 5×10′. The other one is usually 105~2X1
06° is preferably 2 x 105-106. If the molecular weights of the low molecular weight component and the high molecular weight component are lower than the above range, the temperature at which offset of the toner to the heat roll occurs (hereinafter abbreviated as HO) will be low, and if the glass transition point (Tg) of the toner is low, reblocking will occur. It happens.

Conversely, as the temperature increases, the minimum fixing temperature (hereinafter abbreviated as MF) increases.

Note that GPC uses tetrahydrofuran (hereinafter TH) as a solvent.
(abbreviated as F), and a calibration curve can be created using standard polystyrene.

To create a polymer that has two peaks in a molecular weight distribution diagram determined by GPC, there are two methods: melt-blending polymers with different molecular weights, mixing and blending them as a solution, and mixing one monomer in a solution of the other. Polymerization Method There is also a method of thermally polymerizing one monomer in the other without using a solvent. Although there are no restrictions on these methods, from the viewpoint of simplifying the production process and improving molecular weight distribution, it is preferable to thermally polymerize one monomer in the other monomer without using a solvent.

The ratio of high molecular weight components to low molecular weight components in the copolymer is usually 10:90 to 70:30. Preferably 20:8
The range is 0 to 50: 50. If it deviates from this range, the balance between HO and MF will collapse, as described above.

Further, the number of GPC peaks of the copolymer may be three or more as long as the above conditions are satisfied.

The ratio of the high molecular weight component to the low molecular weight component is determined from the area ratio divided by a perpendicular line to the valley formed between the peak of the low molecular weight component based on the polymer and the high molecular weight component in the distribution diagram. For polymers having three or more peaks, the molecular weight is divided between the lowest peak and the next lowest peak.

Further, the ratio of the monomers mentioned above may be within this range in the entire copolymer, and the ratios of each of the low molecular weight component and the high molecular weight component do not necessarily have to be within the ranges described above.

In the present invention, in addition to the above-mentioned components, low-volume polyolefins can also be used. Although the low molecular weight polyolefin can be added after the binder of the present invention is manufactured,
For electrophotographic toners, which is the application of this binder, it is more preferable for low molecular weight polyolefins to be uniformly dispersed, as better release effects can be obtained.For this purpose, it is necessary to add them to the system during binder production. is preferred.

The amount of low molecular weight polyolefin blended is usually 30% by weight or less, preferably 20% by weight or less. If it exceeds 30% by weight, the dispersion state will deteriorate.

The weight average molecular weight of the low molecular weight polyolefin is usually from 1,000 to 100,000, preferably from 5,000 to
60゜000 (a): polyethylene, polypropylene, ethylene-α
Olefin (3 to 8 carbon atoms) copolymers (e.g. ethylene 50 wt% or more, especially 70 wt% or more), maleic acid derivatives (maleic anhydride 1,
Dimethyl maleate, diethyl maleate, di-2-ethylhexyl maleate, etc.) adducts, oxides of (c)=(a), (d): ethylenically unsaturated carboxylic acid [(meth)acrylic acid, itaconic acid, etc.] and/or its esters [
Examples include copolymers of alkyl (C1-Cl8) esters and ethylenically unsaturated hydrocarbons (ethylene, propylene, butene-1, etc.), and mixtures of two or more thereof.

Among the above low molecular weight polyolefins, (a) is a high molecular weight polyolefin (the molecular weight is usually 10,000 to 2.000).
.

000), or by monopolymerizing or copolymerizing olefins.

(B) can be obtained by subjecting a low molecular weight polyolefin to an addition reaction with a maleic acid derivative in the presence of a peroxide catalyst or in the absence of a catalyst. (jl) can be obtained by oxidizing a low molecular weight polyolefin with oxygen or an oxygen-containing gas (air), or by oxidizing it with ozone-containing oxygen or an ozone-containing gas (air). The acid value of the oxide is usually 100 or less,
Preferably it is 50 or less. (d) is an ethylenically unsaturated carboxylic acid and/or its alkyl ester (C1
~Cl8) and an ethylenically unsaturated hydrocarbon. The amount of ethylenically unsaturated carboxylic acid and/or its alkyl ester is usually 30% by weight.
It is preferably 20% or less.

The molecular weight of the low molecular weight polyolefin can be measured by GPC at 135°C using 0-dichlorobenzene as a solvent.

The electrophotographic toner for which the binder of the present invention is used typically contains 50% of the toner binder based on the weight of the toner.
~95%, known coloring materials (carbon black, iron black,
5 to 10% of benzidine yellow, quinacridone, rhodamine B, phthalocyanine, etc.) and magnetic powder (iron,
It is made of 0 to 50% of powder of ferromagnetic metal such as cobalt or nickel, or compound of magnetite, hematite, ferrite, etc.

Furthermore, various additives such as lubricants (such as polytetrafluoroethylene, low molecular weight polyolefins, fatty acids, or metal salts or amides thereof) and charge control agents such as nigrosine and quaternary ammonium salts can be included. The amount of these additives is typically 0 to 5% based on toner weight.
It is.

The electrophotographic toner is produced by dry blending the above components, then melt-kneading, then coarsely pulverizing, and finally finely pulverizing using a jet pulverizer or the like. It is further classified to obtain fine particles having a particle size of usually 5 to 20 microns.

The electrophotographic toner is mixed with carrier particles such as iron powder, glass beads, nickel powder, ferrite, etc., if necessary, and used as a developer for an electrical latent image. Further, hydrophobic colloidal silica fine powder can be used to improve the fluidity of the toner.

As a method for fixing the electrophotographic toner to a support (paper, polyester film, etc.), a known hot roll fixing method can be applied.

[Example] The present invention will be further explained with reference to Examples below, but the present invention is not limited thereto. In the examples, all parts represent parts by weight.

Molecular weight measurement by GPC was performed under the following conditions.

Equipment: Manufactured by Waters Column: 2 Ultra Styla Gel Linear Measurement temperature = 25°C Sample solution 20.5% by weight THF solution Solution injection amount: 200μm Detection device: Refractive index detector The molecular weight calibration curve is Made using standard polystyrene.

Example 1 and Comparative Example 1 490 parts of styrene, 84 parts of butyl acrylate, N.

40 parts of azobisisovaleronitrile was dissolved in a monomer mixture of 91 parts of N-dimethylaminopropylacrylamide and 35 parts of methacrylic acid. 350 parts of toluene was placed in a reaction vessel, and after the temperature was raised to reflux temperature, the mixed monomers were added dropwise and polymerized at 110°C. After toluene was distilled off from the polymer solution, 216 parts of styrene, 84 parts of butyl acrylate, and 0.2 parts of 1,6-hexanediol diacrylate were added and dissolved in the system. Mixture at 100℃
Thermal polymerization was carried out by heating at 120°C for 2 hours, then at 130°C for 2 hours, and at 180°C for 2 hours. A pale yellow solid copolymer obtained by distilling off unreacted monomers was used as the binder (1) of the present invention. A light-colored solid copolymer obtained by polymerizing in the same manner as the polymerization of Binder (1) without adding methacrylic acid was used as Comparative Binder (1). In the molecular weight distribution diagram by GPC of binder (1), 4.80
It had peak molecular weights at 0 and 280,000, and the ratio of high molecular weight components to low molecular weight components was 28:72.

Similarly, comparison binder (1) is 4,900 and 300.0
It had a peak molecular weight at 0.00, and the ratio of high molecular weight components to low molecular weight components was 33:67.

890 parts each of binder (1) and comparative binder (1), 60 parts of carbon black MA-100 (manufactured by Mitsubishi Chemical Industries, Ltd.), 30 parts of Viscoel 550P (manufactured by Mitsubishi Chemical Industries, Ltd., low molecular weight polypropylene) and After powder blending 20 parts of nigrosine (reagent, Gyudon Chemical Co., Ltd.), it was heated at 140°C x 3 in a laboplasto mill.
The mixture was kneaded at 0 rpm for 10 minutes, and the resulting kneaded product was pulverized using a jet mill PJM100 (manufactured by Nippon Pneumatic Co., Ltd.). Using an air classifier MDS (manufactured by Nippon Ninimatic Co., Ltd.), powders having a particle size of 5 to 20 μm were obtained from the finely pulverized product, and used as toner (1) and comparative toner (1), respectively. Electrophotographic carrier iron powder A is added to 25 parts of these toners.
1,000 parts of SR-10 (manufactured by Nippon Tetsuko Co., Ltd.) was mixed and triboelectrically charged in a tumbler-shaker mixer.
When the charge amount was measured using a blow-off charge measurement device (manufactured by Toshiba Chemical Corporation), the toner (1) was +15μ.
C/gp comparison toner (1) was +16μC/g, which was not much different, but when the charge distribution was measured using a 2-particle charge measurement device (manufactured by Hosokawa Micron Co., Ltd.), toner (1) was better. It was sharper than comparative toner (1). OPC using toner (1) and comparative toner (1)
When copies were made using an electrophotographic copying machine for positively charged toner using a photoreceptor, toner (1) gave an image with very little fog, but fog occurred with comparative toner (1).

Example 2 In the same manner as in Example 1, 425 parts of styrene, 65 parts of butyl methacrylate, and 10 parts of N,N-dimethylaminopropylacrinoamide were mixed with 35 parts of azobisisovaleronitrile in 250 parts of toluene. After polymerization as an initiator, the solvent was distilled off, and 251 parts of styrene, 235 parts of butyl methanacrylate, 10 parts of N,N-dimethylaminopropylacrylamide, 4 parts of acrylic acid, 0. Part 3 and Viscole 5
A light yellow solid copolymer obtained by thermal polymerization with the addition of 15 parts of 50P was used as a binder (2). Binder (2)
) had peak molecular weights at 4.800 and 249,000, and the ratio of high molecular weight components to low molecular weight components was 47:53. □ Binder (2) was converted into a toner in the same manner as in Example 1 to obtain toner (2). Using toner (2) with a hot roll type copying machine, the hot roll temperature was 1.60'.
When copying with C, a clear image without low-temperature offset was obtained. Look at this image! When the side image density after rubbing was measured using a rubbing resistance testing machine, the image density remained 80% of the initial density, and no hot offset was observed even when copying at a hot roll temperature of 200°C, indicating excellent thermal properties. was recognized.

Example 3 and Comparative Example 2 In the same manner as in Example 2, 380 parts of styrene, 50 parts of methyl methacrylate, 26 parts of 2-ethylhexyl acrylate, 40 parts of morpholinoethyl methacrylate and 4 parts of maleic anhydride were polymerized, and the solvent was removed. After distillation, 251 parts of styrene, 50 parts of methyl methacrylate, 66 parts of 2-ethylhexyl acrylate, 40 parts of morpholinoethyl methacrylate, 4 parts of maleic anhydride, and 1,6 parts of styrene were added.
-0.3 parts of hexanediol diacrylate was added and thermal polymerization was performed. The obtained polymer was dissolved under reflux in a mixed solvent of 1,000 parts of toluene and 100 parts of methanol, and then added to a large amount of methanol to precipitate the polymer. The obtained copolymer was used as a binder (3). Binder (3
) has peak molecular weights at 4,800 and 260,000, and the ratio of high molecular weight components to low molecular weight components is 50:50.
Met.

A copolymer obtained by polymerization in the same manner except that morpholinoethyl methacrylate was not used was used as a comparative binder (2).
) Toshiga. Comparison binders (2) are 4, 500 and 21
It had a molecular weight of 0,000, and the ratio of high molecular weight components to low molecular weight components was 49:51.

Toner (3) and comparative toner (2) were obtained in the same manner as in Example 1 except that nigrosine was not used. The amount of triboelectricity of toner (3) and comparative toner (2) was measured in the same manner as in Example 1, and the amount of charge of toner (3) was +25 μC/g, but that of comparative toner (2) was -
It was 17 μC/g.

Example 4 Comparative binder (1) 965 parts, toluene 1,000
After adding 116 parts of stearic acid and 116 parts of stearic acid and dissolving under reflux, the copolymer obtained by distilling off the toluene was mixed with a binder (
4).

A toner was obtained in the same manner as in Example 1 to obtain toner (4). When a copying test was conducted in the same manner as in Example 1, the image of toner (4) had less fog than that of comparative I toner (1).

Example 5 and Comparative Example 3 In the same manner as in Example 2, 425 parts of styrene, 65 parts of butyl methacrylate, and 10 parts of N,N-dimethylaminopropylacrylamide were polymerized, and then the solvent was distilled off. 251 parts of styrene, 235 parts of butyl acrylate,
14 parts of N,N-dimethylaminopropylacrylamide, 0.3 parts of 1,6-hexanediol diacrylate and 9 parts of benzoic acid were added, and thermal polymerization was carried out to a peak molecular weight.
The ratio of high molecular weight components to low molecular weight components was 49:51. In addition, after polymerizing 440 parts of styrene and 60 parts of butyl methacrylate in the same manner, 28 parts of styrene
0 parts, butyl methacrylate 220 parts and 1,6-
1-0.3 parts of hexanethiol diacrylate was thermally polymerized to obtain a colorless solid comparative binder (3). Comparative binder (3) has peak molecular weights at 4,500 and 180,000, with a ratio of high to low molecular weight components of 46:
It was 54.

For binder (5) and comparative binder (3),
When the triboelectric charge amount of the binder itself was measured, it was +38 μC/g and -17 μC/g, respectively. Ta.

In addition, binder (5) and comparative binder (3) were each made into toner in the same manner as in Example 1 to obtain toner (5) and comparative toner (3), and the relationship between friction time and charge amount was determined in the same manner as in Example 1. . As shown in Table 1, the charge amount of toner (5) increased faster than that of comparative toner (3).

Table 1: Triboelectric charge amount (unit: μC/g) of toner (5) and comparative toner (3) It is a binder with excellent thermal properties, and when used in positively charged toners, it can provide fog-free images. It is expected that the demand for ζ-tangled positively chargeable toner will become even higher as OPC becomes more widespread in the future, and the present invention is extremely useful.

Claims (1)

[Scope of Claims] 1. A copolymer consisting of a salt of a carboxylic acid and an amino group-containing monomer and a vinyl monomer, which polymer has a molecular weight distribution diagram determined by gel permeation chromatography. A binder for a positively chargeable toner, characterized in that the amount of the amino group-containing monomer in the copolymer is 30 mol % or less. 2. A copolymer consisting of an amino group-containing monomer, a carboxyl group-containing monomer, and a vinyl monomer, which polymer has two or more and the amount of the amino group-containing monomer in the copolymer is 30
A binder for a normally conductive toner, characterized in that it has a mol% or less. 3. The binder according to claim 1 or 2, wherein the quotient obtained by dividing the number of moles of the carboxylic acid or carboxyl group-containing monomer by the number of moles of the amino group-containing monomer is 1 or less. 4. The binder according to any one of claims 1 to 3, wherein the amino group-containing monomer is a monomer represented by the following general formula. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(1) [In the formula, R_1 is hydrogen or an alkyl group having 1 to 6 carbon atoms. R_2 and R_3 are hydrogen, an alkyl group having 1 to 6 carbon atoms, or an aryl group. R_1, R_2 and R_
3 may be the same or different. Further, R_2 and R_3 may be optionally connected to each other to form a 5- or 6-membered ring including the nitrogen atom shown in the above general formula, optionally via an oxygen atom or a nitrogen atom. A is an alkylene group having 1 to 4 carbon atoms. X is -N
H- or -O-. ] 5. The copolymer has at least one peak of 10^3 to 8 x 10^4 in the molecular weight distribution diagram and the other peak of 1
The binder according to any one of claims 1 to 4, which has a molecular weight in the range of 0^5 to 2 x 10^6.