JPH0862895A - Resin composition for electrophotographic toner - Google Patents

Abstract

PURPOSE: To provide a resin compsn. having superior electrostatic charge characteristics even in a toner using a reduced amt. of an electro-static charge regulating agent or not using the agent. CONSTITUTION: This resin compsn. excellent in electrostatic charge characteristics and low-temp. fixability contains a bonding resin consisting of a high density ethylene polymer and a low density ethylene polymer and a compd. selected from among acetoanilide, benzenesulfonamide, 4- acetamidophenol, 4-acetamidothiophenol, phenyl-urea, m-nitrobenzamide, p- methoxybenzamide and benzamide.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a resin composition for an electrophotographic toner for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing and the like.

[0002]

2. Description of the Related Art Although various methods and devices have been developed for fixing processes of copying machines and printers, the most popular method at present is a thermocompression bonding method using a heat roller.

The hot pressing method using a heating roller is a toner.
In contrast, the toner image is fixed by allowing the surface of the heat roller having releasability and the toner image surface of the sheet to be fixed to contact under pressure while passing the sheet to be fixed. Is. This method has very good thermal efficiency in fusing the toner image on the sheet to be fixed, can perform fixing quickly, and is particularly effective in high-speed copying machines, but often has thermal characteristics such as offset phenomenon. Is a problem.

In order to improve the thermal characteristics of the toner, there are known techniques in which the molecular weight of a resin used as a binder is variously controlled and waxes are used in combination. However, although these technologies have great effects on conventional copying machines,
Sufficient performance cannot be obtained with the low-calorific fixing copying machine developed in recent years. For example, when a high molecular weight polymer having a large weight average molecular weight (Mw) is used to achieve offset resistance, the melt flowability of the toner is lowered and the low temperature fixability is lowered, while the low temperature fixability is improved. If a resin with a small Mw is used for the toner, the offset resistance and blocking resistance will be reduced, or the strength of the toner will be insufficient, and the image quality will be impaired due to the toner cracking or chipping during long-term running. Cause

Further, the toner is required to have "charge rising property", that is, the property that the toner charge amount is instantly charged to a predetermined charge amount value when a machine such as a copying machine or a printer is started. In the past, it was general to add a metal-containing dye called a charge control agent (CCA) to the toner in order to improve the chargeability. But,
Recently, this charge control agent contains heavy metals, and since many of them are highly toxic and expensive, the toner resin itself has the function of the charge control agent to reduce the amount of CCA. Attempts have been made not to use it at all. For example, Japanese Patent Publication No. 5-88472 discloses an example in which a polymer containing a maleic acid derivative is applied. However, these techniques have a problem that toner particles are non-uniformly charged, fog is likely to occur, and developability is poor.

[0006]

SUMMARY OF THE INVENTION According to the present invention, even in a toner in which a charge control agent is not used or reduced, the charge rises quickly and the charge stability is good over time, and the melt flowability is excellent, so that it is suitable for low temperature fixing. To obtain an optimum resin composition for electrophotographic toner.

[0007]

The present inventors have completed the present invention as a result of intensive studies to solve the above problems. That is, the present invention has a weight average molecular weight of 300,000 or more and at least one monomer selected from maleic anhydride, monoalkyl maleate and dialkyl maleate 3 to 45.
It contains an ethylene polymer (H) consisting of 50% by weight and 55 to 97% by weight of a styrene monomer, and an ethylene polymer (L) having a weight average molecular weight of 20,000 or less and a Tg of 55 ° C. or more. 100 parts by weight of binder resin, acetanilide, benzenesulfonamide, 4-acetamidophenol, 4-
Resin for electrophotographic toner containing 1.0 to 15 parts by weight of a substance selected from the group consisting of acetamidothiophenol, phenylurea, m-nitrobenzamide, p-methoxybenzamide and benzamide. It is a composition. Hereinafter, the present invention will be described in detail.

The binder resin of the resin composition for an electrophotographic toner according to the present invention comprises an ethylene polymer (H) and an ethylene polymer (L) having a smaller molecular weight than that as a constituent.
The ethylene-based monomer (H) is a styrene-based monomer 55-55.
97% by weight, preferably 60 to 85% by weight, maleic anhydride, monoalkyl maleate or dialkyl maleate 3 to 45% by weight, preferably 15 to 40% by weight, and if necessary, other It may be one in which 0 to 8% by weight of the polymerizable monomer is copolymerized.

The weight average molecular weight (Mw) of the ethylene polymer (H) is 300,000 or more by GPC measurement of the soluble component dissolved in a tetrahydrofuran solution adjusted to 0.25% by weight. It is preferable that Mw is 1,000,000 or less and the width of molecular weight distribution (Mw / Mn) is 5.0 or more and 80 or less for offset resistance. When Mw is more than 1 million, the offset resistance is excellent, but the fixing property tends to decrease.

By introducing maleic anhydride, monoalkyl maleate and dialkyl maleate as a copolymerization component into the ethylene-based monomer (H), the charging characteristics of the toner resin can be improved and the charge control agent can be obtained. A product which can be sufficiently used without (CCA) is obtained. When the copolymerization amount of the monomer selected from maleic anhydride, monoalkyl maleate and dialkyl maleate is less than 3 parts by weight, sufficient charge rising property cannot be obtained,
The charge amount distribution also becomes wide, which is not preferable. When the amount is more than 45 parts by weight, the moisture resistance of the toner decreases,
Further, the productivity of the binder resin also decreases.

The alkyl group of the monoalkyl maleate and dialkyl maleate monomers is preferably a linear or branched alkyl group having 1 to 8 carbon atoms. Specific examples of these monomers include monopropyl maleate, monobutyl maleate, monopentyl maleate, monohexyl maleate, monooctyl maleate, dibutyl maleate, dihexyl maleate, dioctyl maleate, propyl maleate. Butyl, hexyl octyl maleate, and butyl octyl maleate.

Examples of the styrene-based monomer include styrene, α-methylstyrene, halogenated styrene, vinyltoluene, divinylbenzene, p-sulfonamidostyrene and p-styrenesulfonic acid, but are not limited thereto. Not a thing. Other copolymerizable monomers, which are preferably styrene and may be optionally used, include the following. (1) Acrylic acid esters; methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, octyl acrylate, dodecyl acrylate, lauryl acrylate, stearyl acrylate, cyclohexyl acrylate, Phenyl acrylate, benzyl acrylate, furfuryl acrylate, hydroxyethyl acrylate, hydroxybutyl acrylate, dimethylaminomethyl acrylate, dimethylaminoethyl acrylate, 2-ethylhexyl acrylate, 2-chloroethyl acrylate

(2) Methacrylic acid esters; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-methacrylate
Butyl, isobutyl methacrylate, t-butyl methacrylate, octyl methacrylate, decyl methacrylate, dodecyl methacrylate, stearyl methacrylate, lauryl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-methylhexyl methacrylate. , 2-ethylhexyl methacrylate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate, hydroxymethyl methacrylate, hydroxyethyl methacrylate, hydroxybutyl methacrylate, dimethylaminomethyl methacrylate ester, dimethylaminoethyl methacrylate ester, dimethylamino methacrylate ester. Ethyl, diethylaminoethyl methacrylate

(3) Itaconic acid esters; dimethyl itaconic acid, di-n-propyl itaconic acid, itaconic acid-
n-butyl, di-n-octyl itaconate, di-n-amyl itaconate

(4) Unsaturated carboxylic acids and unsaturated dicarboxylic acids; (meth) acrylic acid, cinnamic acid, maleic acid, fumaric acid, itaconic acid (5) Others; 2-vinylnaphthalene, itaconic anhydride The ethylene-based polymer (L) has a molecular weight (Mw) of 20,000 or less and a glass transition temperature (Tg) of 55 ° C. or more, and preferably has a molecular weight distribution width (Mw / Mn, where Mn is a number average molecular weight). Is an ethylene-based polymer having a ratio of 3.0 or less. Particularly, those having Mw of about 5,000 and Tg of 58 to 65 ° C. are preferable. Molecular weight (Mw) is 2
When Mw / Mn is larger than 30,000 and Mw / Mn is 3.0
When it is wider than the above range, the melt viscosity becomes large and it becomes difficult to obtain a sufficiently low fixing temperature. Furthermore, Tg is 5
If the temperature is lower than 5 ° C, the blocking property of the toner is deteriorated, which is not preferable. As the monomer constituting the ethylene polymer (L), the same ones as the ethylene polymer (H) can be used, and preferably styrene monomers, acrylic acid esters and methacrylic acid esters.

The ethylene-based polymers (H) and (L) may be polymerized by a known method, but it is preferable that they are polymerized by bulk polymerization and / or solution polymerization. The mixing ratio of the ethylene-based polymer (H) and the ethylene-based polymer (L) is in the range of 85:15 to 15:85, preferably 70:30 to 30:70. It is preferable for maintaining the balance of offset resistance. Further, the glass transition temperature (Tg) of the resin composed of the ethylene polymer (H) and the ethylene polymer (L)
In order to optimize the storage property and fixing property of the toner.
It is preferably 0 to 70.0 ° C.

The binder resin may be, for example, a polyvinyl chloride resin, a polyolefin resin, a polyester resin, a polyvinyl butyral, a polyurethane resin or a polyamide resin, as long as the effect of the present invention is not impaired. , Rosin, terpene resin, phenol resin, epoxy resin, paraffin wax and the like may be added.

The toner resin composition of the present invention contains acetanilide, benzenesulfonamide,
4-acetamidophenol, 4-acetamidothiophenol, phenylurea, m-nitrobenzamide,
One or more of p-methoxybenzamide or benzamide must be used. By using these substances, the balance between the melt fluidity and the glass transition temperature (Tg) of the toner resin can be optimized. In other words, it is possible to further improve the melt fluidity, which greatly affects the fixability, while keeping the Tg that greatly affects the blocking property high (those having a high Tg have good blocking property). That is, it is possible to obtain a resin that has excellent blocking properties and can be used for low-temperature fixing. Of these, acetanilide is most preferred.

The addition amount of the above-mentioned specific additive needs to be 1.0 to 15 parts by weight with respect to 100 parts by weight of the binder resin, and the addition amount is less than 1.0 part by weight. In this case, the Tg of the toner becomes high and the blocking property is satisfied, but the fixing temperature becomes high and it is against the energy saving movement of the copying machine, which is not preferable. On the other hand, when the amount is more than 15 parts by weight, the additive concentration between the toner particles becomes non-uniform due to poor dispersion of the additive, which is not preferable because reverse charging occurs and the charge amount distribution spreads. .

In the present invention, as a method for mixing the binder resin with the specific additive, the addition is carried out in the step of mixing the ethylene polymer (H) resin solution and the ethylene polymer (L) resin solution and removing the solvent. However, the addition of the binder resin, the colorant and other components required for the toner in the pre-mixing step or the melt-kneading step is exemplified.
It is not limited to this.

The amount of the mixed resin of the ethylene polymers (H) and (L) in the present invention is usually 5 in the toner composition.
0 to 95 parts by weight. A low molecular weight polyolefin wax may be added to the resin composition of the present invention in order to improve the physical properties when it is used as a toner. The low molecular weight polyolefin wax may be either an unmodified polyolefin wax or a modified polyolefin wax in which a modifying component is blocked or grafted with respect to an olefin component. The olefin component of the unmodified polyolefin wax or the modified polyolefin wax is a homopolymer obtained from a single olefin monomer.
Any type of copolymer or copolymer type obtained by copolymerizing a unit or an olefin monomer with another monomer copolymerizable therewith may be used. The addition amount is preferably 5 to 20% by weight in the toner composition.

Specific examples of the polyolefin wax include "Viscole 660P" and "Viscole 550P".
(Above, Sanyo Chemical Co., Ltd.), "Polyethylene 6A" (manufactured by Allied Chemical Co., Ltd.), "High Wax 400P", "High Wax 100P", "High Wax 200P",
"High Wax 320P", "High Wax 220
"P", "High Wax 2203P", "High Wax 4"
202P "(Mitsui Petrochemical Co., Ltd.)," Hoechst Wax PE520 "," Hoechst Wax PE13 "
0 "," Hoechst Wax PE190 "(above, manufactured by Hoechst Japan Co., Ltd.), polyethylene wax obtained by block copolymerization or graft copolymerization of methyl methacrylate, and block copolymerization or grafting of butyl methacrylate. Examples thereof include copolymerized polyethylene wax and polyethylene wax obtained by block- or graft-copolymerizing styrene. These polyolefins are usually mixed with the resin composition during melt kneading in toner production, but may be added during polymerization of the ethylene polymer or solvent removal.

A colorant is usually used in the electrophotographic toner composition using the resin composition of the present invention. Examples of colorants that can be used include carbon black, acetylene black, lamp black, black pigments such as magnetite, yellow lead, yellow iron oxide, Hansa yellow G, quinoline yellow lake, permanent yellow, NCG molybdenum. Orange, balkan orange, indanthrene, red iron oxide, brilliant orange GK, brilliant carmine 6B, fryzarin lake, fast violet B,
Known pigments such as cobalt blue, alkali blue lake, phthalocyanine blue, metal complex of monoazo dye, fast sky blue, pigment green B, malachite green lake, titanium oxide and zinc white. Is mentioned. The amount is usually 5 to 3 with respect to 100 parts by weight of the resin composition.
It is 00 parts by weight. The toner resin composition of the present invention can be made into a toner by a known method by appropriately selecting and adding a pigment dispersant, an offset preventing agent and the like.

That is, the resin composition to which the above-mentioned various additives are added is premixed with a Henschel mixer, and then kneaded in a heating and melting state with a kneader such as a biaxial kneader or a static mixer, cooled, and jet pulverized. After finely pulverizing with a machine, it is classified with a classifier, and particles in the range of usually 8.0 to 20.0 μm are collected to be a toner. Magnetic powder may be contained in order to obtain a magnetic toner. Such magnetic powders include ferromagnetic substances magnetized in a magnetic field, powders of iron, nickel, cobalt, etc., or alloys such as magnetite, ferrite, etc. The ratio of the magnetic powders relative to the toner weight. 15 to 70 parts by weight is preferable.

Further, in the present invention, a releasing agent as described below may be appropriately used during polymerization or during melting / kneading. The releasing agent referred to here is a substance which is brought into contact with the fixing roller at the time of fixing to reduce friction, improve releasability, or improve fluidity at the time of melting, for example, paraffin wax, Higher (saturated straight chain) fatty acids (C12-5)
0), higher alcohols (having 8 to 32 carbon atoms), fatty acid metal salts, fatty acid amides, metal soaps, polyvalent alcohols and the like. In the toner, if necessary, a coloring agent,
The powder fluidity modifier may be mixed with the toner particles (externally added) and used. Also, by preventing the toner-particle mutual aggregation,
In order to improve the powder fluidity, a powder fluidity improver such as Teflon fine powder may be added.

[0026]

The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples. In the following, “parts” means parts by weight unless otherwise specified.

Production Examples 1 to 7 (Production Example of Ethylene Polymer (H)) A four-necked flask was equipped with a cooling tube, a thermometer, a nitrogen introducing tube and a stirring device, and 94.0 parts of a styrene monomer, 6.0 parts of maleic anhydride was charged, the internal temperature was raised to 110 ° C., the temperature was kept at the same temperature, and bulk polymerization was carried out for 7.0 hours. Then, 70 parts of xylene and 0.2 part of divinylbenzene were added, and the mixture was mixed and dissolved in advance.
0.3 part of butylperoxide, 30 parts of xylene and 0.1 part of divinylbenzene were continuously added dropwise over 7.0 hours while maintaining the temperature at 130 ° C., and then the reaction was continued for 1 hour to complete the polymerization to obtain the polymer 1. Obtained. Tables 1 and 2 also show polymers 2 to 7.
It was obtained in the same manner as in Production Example 1 under the production conditions shown in.

Production Examples 8 to 12 (1-2 Production Example of Ethylene Polymer (L)) Cooling Tube,
A four-necked flask equipped with a thermometer, a nitrogen introducing tube and a stirrer was charged with 100 parts of xylene solvent, heated to a reflux temperature while introducing nitrogen, and 100 parts of styrene monomer and t-
10 parts of butylperoxy-2-ethylhexanoate was continuously added dropwise over 6.5 hours, and after 1 hour of post-polymerization, the remaining monomer was polymerized to obtain a polymer 8. Polymer 9-12
Was obtained in the same manner as in Production Example 8 under the production conditions shown in Table 2.

The molecular weights of the ethylene polymers (L) and (H) obtained by the above production examples are standardized on the commercially available monodisperse standard polystyrene, and tetrahydrofuran is used as the solvent.
It was determined by GPC using a refractometer as a detector. Detector SHODEX RI SE-31 column A-80M x 2 + KF-802 solvent THF (tetrahydrofuran) discharge rate 1.2 ml / min sample 0.25% THF solution The acid value of the ethylene polymer was neutralized. Xylene /
A precisely weighed sample was dissolved in an n-butanol mixed solvent, titrated with a previously standardized 0.1 N sodium hydroxide alcohol solution, and calculated from the neutralized amount by the following formula.

[0030]

[0031]

[Table 1]

[0032]

[Table 2] Examples 1 to 10 and Comparative Examples 1 to 8 The polymer solution of the ethylene-based polymer (H) and the polymer of the ethylene-based polymer (L) obtained as described above are mixed at an arbitrary ratio, and the solvent is removed. To obtain a binder resin.

Next, 100 parts of the binder resin, 10 parts of carbon black, 5 parts of polypropylene wax, and a predetermined amount of a specific additive were premixed in a Henschel mixer, and then set to 170 ° C. using a biaxial kneader. And kneading, then cooling,
Coarse pulverization, fine pulverization, classification with a classifier, 6.0-18.0μ
m toner was obtained.

Using the toner described above, the fixability, anti-offset property, charge rising property, etc. were evaluated. The fixability and offset resistance were evaluated using a machine modified so that the roll temperature of a commercial copying machine could be arbitrarily changed. Next, an evaluation method will be shown. (A) Fixing property: A toner layer of 2 cm × 2 cm in solid black part on the image quality was sanded with a load of 250 g / cm ^{2 using} a Gakushin type friction fastness tester (manufactured by Daiei Kagaku Seiki Seisakusho Co., Ltd.). The residual weight ratio of the toner layer after rubbing 50 times with an eraser is 70%.
Was the lowest heat roll temperature required to exceed. (B) Offset resistance: The heat roll temperature was raised to a temperature at which a high temperature offset phenomenon began to occur. (C) Blocking property: 100 g of Tona was put in a polybin, tapped, kept at 50 ° C. for 50 hours, then returned to room temperature, transferred to a paraffin paper, and visually judged according to the following judgment criteria. ◎: No blocking at all ○: Little blocking but no problem in practical use △: Very blocking ×: Completely blocking and unusable (d) High-speed durability; Commercial high-speed copying machine ( (72 sheets / minute copying speed) 10,000 sheets continuous test was conducted, and patterns were copied to check reproducibility. The difference in image quality was checked before and after the continuous test. ○: Almost no difference before and after copying △: ID greatly decreased after continuous test ×: Fog occurred and image quality was significantly disturbed (e) Evaluation of charge buildup; Tona-1g and Powder Tech Co. 49 g of carrier iron powder (F95-100)
After mixing and stirring for 1 minute and 60 minutes with a bra-shaker mixer, the triboelectric charge amount was measured with a blow-off charge amount measuring device manufactured by Toshiba Chemical Co., and the charge amount at 1 minute and 60 minutes of mixing and stirring (respectively, The ratio of (expressed as Q1 and Q60) was evaluated. T = (Q60 / Q1) ○ (good); T ≤ 2 Δ (suspicious good); 2 <T ≤ 3.5 × (poor); 3.5 <T Table 2 shows the measurement results of the above toner physical properties. Show.

[0035]

[Table 3]

[0036]

INDUSTRIAL APPLICABILITY By using the toner resin composition for electrophotography of the present invention, the amount of the charge control agent (CCA) used, which could not be solved by the prior art, is reduced or is not used.
Also in the composition, it was possible to provide sufficient charging characteristics (rise property).

Claims (2)

[Claims] 1. A weight average molecular weight of 300,000 or more, and 3 to 45% by weight of at least one monomer selected from maleic anhydride, monoalkyl maleate and dialkyl maleate, and 55 to 97% by weight of styrenic monomer. % Ethylene polymer (H) and weight average molecular weight of 20,000 or less and Tg of 55 ° C.
100 parts by weight of a binder resin containing the above ethylene polymer (L), acetanilide, benzenesulfonamide, 4-acetamidophenol, 4-acetamidothiophenol, phenylurea and m-nitrobenzamide. , 1.0 to 15 parts by weight of a substance selected from the group consisting of p-methoxybenzamide and benzamide, and a resin composition for an electrophotographic toner. 2. A toner containing the resin composition according to claim 1.