JPH11295916A - Release agent for electrostatic toner and electrostatic toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electrostatic toner which has excellent release property during thermal fixing, especially excellent release property during low energy fixing, and excellent blocking resistance, fixing property and dispersibility of pigments, which does not cause offset development, which prevents contamination on a carrier, photoreceptor and heating roll, and which does not cause filming or disturbance in an image. SOLUTION: This release agent for an electrostatic toner consists of a propylene polymer containing a magnesium metal or magnesium compd. by 1 to 10000 ppm by weight expressed in terms of magnesium atom and having >=90 mol.% propylene content, 3000 to 50000 weight average mol.wt. measured by gel permeation chromatography(GPC), and 120 to 140 deg.C melting point measured by differential scanning calorimetry(DSC).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a release agent for an electrostatic toner comprising a propylene-based polymer and an electrostatic toner containing the release agent.

[0002]

2. Description of the Related Art An electrostatic toner (electrophotographic toner) is a developing material used in electrostatic electrophotography to develop a latent image formed by charging and exposure to form a visible image. This electrostatic toner has carbon black,
It contains a chargeable fine powder in which a coloring agent such as another pigment is dispersed as a developing material. Such an electrostatic toner is
A dry two-component toner used by dispersing the chargeable fine powder together with a carrier such as iron powder and glass particles, a wet toner prepared by dispersing the chargeable fine powder using an organic solvent such as isoparaffin, and the magnetic toner. Dry single-component toners in which fine powder is dispersed in the gas phase are roughly classified.

By the way, an image obtained by developing on a photoreceptor with electrostatic toner is transferred to paper, and an image obtained by direct development on paper on which a photosensitive layer is formed is directly heated, Fixed by solvent vapor. Among them, fixing by a heating roller is a contact-type fixing method, so that it has high thermal efficiency, can reliably fix an image even with a relatively low-temperature heat source, and is suitable for high-speed copying. have.

[0004] In particular, in recent years, the use range of electrophotography has expanded,
There is an increasing need to fix electrostatic toner with lower energy than before. For example, as the advance of electrophotography into home appliances progresses, reduction in power consumption of the heating roller unit is required. In addition, improvement in high-speed fixing property is also required for electrostatic toner used in output terminals of high-speed devices such as computers.

[0005] However, when an image is fixed by contacting a heating member such as a heating roller, if the conventional electrostatic toner is used, an offset phenomenon, that is, a part of the electrostatic toner adheres to the heating member and a subsequent image portion is formed. Transfer phenomenon may occur. In particular, when the temperature of the heating roller is low, the electrostatic toner does not sufficiently soften, so that the fixing property to printing paper or a film is lowered, and at the same time, an offset phenomenon is likely to occur. Further, when copying at a high speed, if the heating element is heated to a high temperature in order to improve the fixing effect and the fixing speed, an offset phenomenon is likely to occur. For this reason, for example, the surface of the heating roller is impregnated with silicone oil, or the method of supplying the silicone oil to the surface of the heating roller is used to eliminate the offset phenomenon. Etc. may occur.

Further, various thermoplastic resins are used as a binder resin as a component of the electrostatic toner. In particular, a low molecular weight styrene / (meth) acrylate copolymer has good chargeability, It has an appropriate softening point around ℃, so it is easy to fix, it is easy to wash the photoreceptor, there is little sludge, it has low moisture absorption, it has good mixing with carbon black as a colorant, and it is further pulverized. It is widely used because it has advantages such as easy operation. However, conventional electrostatic toners using this low-molecular-weight styrene / (meth) acrylate copolymer as a binder resin also require fixing with a low-temperature heating roller or high-speed copying.
There has been a problem that the offset phenomenon easily occurs.

[0007] In order to solve such a problem, it has been proposed to mix the toner with an electrostatic toner as a release agent comprising a polyolefin wax such as low-molecular-weight polyethylene or polypropylene (Japanese Patent Publication No. 52-3304).
JP-A-52-3305, JP-A-57-52574,
JP-A-58-58664 and JP-A-58-59455. However, the release agents composed of polyolefin waxes described in these publications have a problem that their performance varies.

Further, even in the conventional electrostatic toner to which a release agent made of a polyolefin wax is added, good fixability cannot be exhibited under recent low-energy fixing conditions.
For this reason, the offset phenomenon has not yet been prevented.

In addition, a conventional electrostatic toner to which a release agent made of a polyolefin wax is added has a reduced anti-blocking property, blocking of the electrostatic toner occurs in the toner cartridge, and the toner is transferred from the toner cartridge to the photosensitive member. Another problem that the electrostatic toner is not supplied may occur. Further, a filming phenomenon, that is, a phenomenon in which a low-crystalline substance contained in the polyolefin wax adheres to the surface of a carrier, a photoconductor, a heating roller, or the like occurs, and an electrostatic latent image is formed on the photoconductor, In some cases, the charge of the toner is adversely affected, and the resulting image is significantly disturbed.

Incidentally, as a catalyst for propylene polymerization,
There are catalysts using titanium trichloride and triethylaluminum and diethylchloroaluminum. In this catalyst, the polymerization amount of propylene per unit catalyst (hereinafter, referred to as activity) is low, so that a large amount of catalyst residue is incorporated into polypropylene. For this reason, after the polymerization, a catalyst removal treatment (demineralization treatment) is performed by washing with water or alcohol.
The ash content (mainly M
g, metal components such as Al) are reduced, so that the deterioration of various physical properties such as the hue and heat resistance of polypropylene is suppressed,
Quality is stable. However, even when such a decalcified polypropylene is used as the release agent, an electrostatic toner that is excellent in release property at the time of low energy fixing and blocking resistance, and does not cause an offset phenomenon or a filming phenomenon is used. I can't get it.

As another propylene polymerization catalyst, there is a titanium catalyst containing a solid titanium catalyst component comprising a magnesium compound, a titanium compound and an electron donor.
Since the activity of the titanium-based catalyst is high per unit catalyst, the amount of the titanium-based catalyst used can be reduced, so that the catalyst removal treatment is omitted. Since the catalyst remains in this undemineralized polypropylene as ash (residue) as it is, a larger amount of magnesium compound is contained than in the deashed polypropylene, but the magnesium compound in this ash has an effect on the performance of the release agent. It has never been considered a major effect.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide a mold having excellent releasability at the time of heat fixing, particularly at the time of low energy fixing, and having excellent blocking resistance, fixing property and pigment dispersibility. Electrostatic toner is obtained, and furthermore, the offset phenomenon does not occur, and the carrier, the photoconductor, the heating roll, etc. are prevented from being contaminated, the filming phenomenon does not occur, and the electrostatic toner that does not disturb the image is stably formed. An object of the present invention is to provide a release agent for an electrostatic toner that can be obtained. Another object of the present invention is to provide excellent releasability during heat fixing, particularly excellent releasability during low-energy fixing, as well as excellent blocking resistance, fixing properties and pigment dispersibility, and without causing an offset phenomenon. Another object of the present invention is to provide an electrostatic toner which prevents contamination of a carrier, a photoreceptor, a heating roll and the like, does not cause a filming phenomenon, and does not cause image disturbance.

[0013]

The inventors of the present invention have studied the causes of variations in the performance of an electrostatic toner containing a propylene polymer, and found that the performance differs depending on the method of producing the propylene polymer. It was recognized that, as a result of further studies, it was found that when the content of the magnesium compound derived from the polymerization catalyst was a specific amount, excellent performance as a mold release agent was exhibited, and completed the present invention. .

That is, the present invention relates to the following release agent for electrostatic toner and electrostatic toner. (1) Magnesium metal or magnesium compound is converted to magnesium atom by weight on the basis of 1 to 10,000.
ppm, the propylene content is 90 mol% or more, and the weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) is 3000 to 5000.
0, melting point measured by differential scanning calorimeter (DSC) is 1
A release agent for electrostatic toner comprising a propylene polymer at 20 to 140 ° C. (2) The release agent for an electrostatic toner according to the above (1), wherein the magnesium metal or the magnesium compound is derived from a polymerization catalyst. (3) The electrostatic toner according to the above (1) or (2), wherein the magnesium metal or the magnesium compound is derived from a solid titanium catalyst component comprising a magnesium metal or a magnesium compound, a titanium compound and an electron donor. Mold. (4) A polymer in which a propylene-based polymer is polymerized using a titanium-based catalyst containing a solid titanium catalyst component composed of magnesium metal or a magnesium compound, a titanium compound and an electron donor, and the catalyst is not removed after the polymerization. The release agent for an electrostatic toner according to any one of the above (1) to (3), which is a polymer obtained by heating and degrading this polymer. (5) An electrostatic toner containing the release agent for electrostatic toner according to any one of (1) to (4).

The propylene polymer constituting the release agent for an electrostatic toner of the present invention has a propylene content of 90 mol% or more, preferably 94 mol% or more, and more preferably 96 mol% or more.
It is a propylene homopolymer or a copolymer of propylene and another α-olefin at １００100 mol%. Other α-olefins copolymerized with propylene include those having 2 carbon atoms.
Or 4 to 12, preferably 2 or 4 to 6 α-olefins. The copolymer may be a binary copolymer or a tertiary or higher multi-component copolymer.

Other α-olefins copolymerized with propylene include ethylene, butene-1, pentene-1, 2
-Methylbutene-1,3-methylbutene-1, hexene-1,3-methylpentene-1,4-methylpentene-
1,3,3-dimethylbutene-1, heptene-1, methylhexene-1, dimethylpentene-1, trimethylbutene-1, ethylpentene-1, octene-1, methylpentene-1, dimethylhexene-1, trimethyl Pentene-1, ethylhexene-1, methylethylpentene-1, diethylbutene-1, propylpentene-1, decene-1, methylnonene-1, dimethyloctene-1,
Examples thereof include trimethylheptene-1, ethyloctene-1, methylethylheptene-1, diethylhexene-1, dodecene-1, and hexadodecene-1.

The propylene polymer is preferably a propylene / ethylene copolymer, a propylene / butene copolymer, a propylene / ethylene / butene copolymer, or the like.
Particularly, a propylene / ethylene copolymer is preferable. The propylene-based polymer may be used singly, or 2
More than one species can be used in combination.

The propylene polymer has a weight average molecular weight (Mw) of 3 in terms of polystyrene measured by GPC.
000 to 50,000, preferably 5000 to 4500
0, the melting point measured by DSC is 120 to 140 ° C, preferably 123 to 138 ° C. The propylene polymer has a density of 0.8 as measured according to JIS K6760.
8 to 0.92 g / cm ³ , preferably 0.89 to 0.9
1 g / cm ^3, a softening point measured by JIS K2207 is one hundred twenty-five to one hundred sixty ° C., it is desirable that preferably 140 to 155 ° C..

The propylene-based polymer constituting the release agent of the present invention contains magnesium metal or a magnesium compound in an amount of 1 to 10,000 by weight as magnesium atom.
ppm, preferably 1 to 20 ppm. When the content of the magnesium metal or the magnesium compound (hereinafter, sometimes referred to as magnesium content) is within the above range, the releasability at the time of heat fixing, particularly the releasability at the time of low energy fixing is excellent, and the blocking resistance is improved. An electrostatic toner having excellent fixability and pigment dispersibility can be obtained, and furthermore, an offset phenomenon does not occur, and contamination of a carrier, a photoreceptor, a heating roll, etc. is prevented, and a filming phenomenon does not occur. An electrostatic toner free from disturbance can be stably obtained.

Specific examples of the magnesium compound include MgO, Mg (OH) ₂ , MgCl ₂ , MgCl ₂ .n
C ₂ H ₅ OH, Mg (OC ₂ H ₅ ) ₂ , MgCl (OC ₂ H ₅ ) and the like. The main component is MgCl ₂ .

The magnesium metal or magnesium compound contained in the propylene-based polymer is preferably, but not limited to, the one derived from the polymerization catalyst used for the polymerization of the propylene-based polymer, since the one is uniformly dispersed.

Examples of the polymerization catalyst serving as a supply source of the magnesium metal or the magnesium compound include a titanium catalyst containing a solid titanium catalyst component comprising a magnesium compound, a titanium compound and an electron donor. The titanium-based catalyst containing the solid titanium catalyst component is widely used as a high-activity polymerization catalyst for a propylene-based polymer,
These known catalysts can be sources of magnesium.
Specific examples of the catalyst include a titanium-based catalyst containing a solid titanium catalyst component and an organoaluminum compound.

The solid titanium catalyst component is prepared by contacting a titanium compound, a magnesium compound and an electron donor as described below. As the titanium compound, a trivalent titanium compound or a tetravalent titanium compound is used, and a tetravalent titanium compound is preferable. 4
For example, Ti (OR) _k X
_4-k (R is a hydrocarbon group, X is a halogen atom, 0 ≦ k ≦
The tetravalent titanium compound represented by 4) can be mentioned.

Specific examples of the titanium compound include T
titanium tetrahalides such as iCl ₄ , TiBr ₄ , and TiI ₄ ;
Ti (OCH ₃ ) Cl ₃ , Ti (OC ₂ H ₅ ) Cl ₃ , Ti (On-C ₄ H
_{9) Cl 3, Ti (OC} 2 H 5) Br 3, Ti (Oiso-C 4 H 9) trihalide alkoxy titanium Br ₃ such; Ti (OCH _{3) 2} Cl
₂ , Ti (OC ₂ H ₅ ) ₂ Cl ₂ , Ti (On-C ₄ H ₉ ) ₂ Cl ₂ , Ti
Dihalogenated alkoxytitanium such as (OC ₂ H ₅ ) ₂ Br ₂ ;
Ti (OCH ₃ ) ₃ Cl, Ti (OC ₂ H ₅ ) ₃ Cl, Ti (On-C ₄ H
₉ ) ₃ Cl, Ti (OC ₂ H ₅ ) ₃ Br and other monohalogenated trialkoxy titanium; Ti (OCH ₃ ) ₄ , Ti (OC ₂ H ₅ ) ₄ , Ti
Tetraalkoxy titanium such as (On-C ₄ H ₉ ) ₄ ; mixtures thereof; aluminum compounds and silicon compounds;
Examples thereof include a mixture with another metal compound such as a sulfur compound, hydrogen halide, and halogen. Among these, a halogen-containing titanium compound is preferable, a titanium tetrahalide is more preferable, and titanium tetrachloride is particularly preferable.

The magnesium compound used for preparing the solid titanium catalyst component may be a magnesium compound having a reducing property or a magnesium compound having no reducing property. Examples of the magnesium compound having a reducing property include a magnesium compound having a magnesium-carbon bond and a magnesium-hydrogen bond. As the magnesium compound having no reducibility, a compound derived from the magnesium compound having reducibility or a compound derived at the time of preparing the catalyst component can be used. Further, a complex compound, a complex compound of these magnesium compounds and other metals, or a mixture with other metal compounds can also be used. These magnesium compounds may be a mixture of two or more.

As the magnesium compound, a magnesium compound having no reducing property is preferable. Examples of the magnesium compound having no reducing ability include magnesium halides such as magnesium chloride, magnesium bromide, magnesium iodide, and magnesium fluoride; methoxy magnesium chloride, ethoxy magnesium chloride, isopropoxy magnesium chloride, butoxy magnesium chloride, octoxy magnesium chloride. Alkoxymagnesium halides such as phenoxymagnesium chloride and methylphenoxymagnesium chloride;
Ethoxymagnesium, isopropoxymagnesium,
Butoxymagnesium, n-octoxymagnesium,
Alkoxy magnesium such as 2-ethylhexoxy magnesium; allyloxy magnesium such as phenoxy magnesium and dimethylphenoxy magnesium; and magnesium carboxylate such as magnesium laurate and magnesium stearate. Of these, halogen-containing magnesium is preferred, and magnesium chloride, alkoxymagnesium chloride and allyloxymagnesium chloride are particularly preferred.

Examples of the electron donor used for preparing the solid titanium catalyst component include carboxylic esters, aliphatic carboxylic acids, acid anhydrides, ketones, aliphatic ethers, aliphatic carbonates, alcohols containing alkoxy groups, and aryloxy. Examples include a group-containing alcohol, an organic silicon compound having a Si—O—C bond, and an organic phosphorus compound having a P—O—C bond.

Specific examples of the electron donor include:
Methyl formate, methyl acetate, ethyl acetate, vinyl acetate, propyl acetate, iso-butyl acetate, tert-butyl acetate, octyl acetate, cyclohexyl acetate, ethyl propionate, methyl butyrate, ethyl valerate, ethyl pyruvate, ethyl pivalate, Methyl chloroacetate, ethyl dichloroacetate, methyl methacrylate, ethyl crotonate, methyl cyclohexanecarboxylate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, octyl benzoate, cyclohexyl benzoate, phenyl benzoate, phenyl benzoate Benzyl acid, methyl toluate, ethyl toluate, amyl toluate, ethyl benzoate,
Monocarboxylic acid esters such as methyl anisate, ethyl anisate and ethyl ethoxybenzoate; aliphatic carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, and valeric acid; acetic anhydride, maleic anhydride, benzoic anhydride, and phthalic anhydride Acid, trimellitic anhydride, acid anhydride such as tetrahydrophthalic anhydride; acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl n-butyl ketone, acetophenone,
Ketones such as benzophenone, cyclohexanone, and benzoquinone; aliphatic ethers such as methyl ether, ethyl ether, isopropyl ether, butyl ether, amyl ether, ethylbenzyl ether, ethylene glycol dibutyl ether, and anisole; and alkoxy group-containing alcohols such as butyl cellosolve and ethyl cellosolve; Aliphatic carbonates such as dimethyl carbonate, diethyl carbonate, and ethylene carbonate; organic silicon compounds such as methyl silicate, ethyl silicate and diphenyldimethoxysilane; and having a P-O-C bond such as trimethyl phosphite and triethyl phosphite And organic phosphorus compounds.

The solid titanium catalyst component can be produced by bringing the above titanium compound, magnesium compound (or magnesium metal), and an electron donor into contact. The above components may be contacted in the presence of other reaction reagents such as, for example, silicon, phosphorus, aluminum and the like. In order to produce a solid titanium catalyst component, a known method for preparing a highly active titanium catalyst component from a titanium compound, a magnesium compound and an electron donor can be employed. For example, there is a method in which a magnesium compound is dissolved in alcohol, an electron donor is added, and the solution is mixed with a liquid titanium compound to form a solid product.

As the organoaluminum compound forming the titanium-based catalyst, a compound having at least one Al-carbon bond in the molecule can be used. As such a compound, for example, a compound represented by the formula (1) (R ¹ ) _m Al (OR ² ) _{n Hp} X _q (1) [In the formula (1), R ¹ and R ² usually represent a carbon atom. 1 to 15
, Preferably 1 to 4 hydrocarbon groups, which may be the same or different from each other. X is a halogen atom. m is 0 <m ≦ 3, n is 0 ≦ n <3, and p is 0 ≦ p <
3, q is a number satisfying 0 ≦ q <3, and m + n
+ P + q = 3. Or an organoaluminum compound represented by the formula (2) (M ¹ ) Al (R ¹ ) ₄ ... (2) [In the formula (2), M ¹ is Li, Na or K, and R ¹ is It is the same as R ^{1 in the} formula (1). And the like.

The solid titanium catalyst component, a titanium-based catalyst containing the catalyst component, a method for preparing them and a polymerization method are described in detail in, for example, JP-A-58-83006.

Since the titanium-based catalyst is a highly active catalyst and has a small amount of catalyst residues, the catalyst removal treatment (deashing treatment) is usually omitted in the production of polyolefins such as propylene-based polymers using this catalyst. In the present invention, such a non-demineralized propylene-based polymer from which the catalyst has not been removed can be preferably used. The non-demineralized propylene-based polymer usually contains a magnesium metal or a magnesium compound within the range of the above-mentioned magnesium content. A chlorine absorbent such as calcium stearate is usually used in such a non-deashed propylene-based polymer to prevent generation of chlorine due to a catalyst residue.
About m is added, but such a chlorine absorbent may be contained in the propylene-based polymer constituting the release agent of the present invention.

For producing a propylene-based polymer using the above-mentioned titanium-based catalyst, a known production method can be adopted. For example, in an inert medium such as hexane, peptane, kerosene or the like in the presence of a titanium-based catalyst. By reacting propylene and other copolymerized monomers.

As the propylene polymer constituting the release agent of the present invention, a polymer obtained by heating and degrading a high molecular weight propylene polymer can be used. The high-molecular-weight propylene-based polymer to be thermally degraded is preferably polymerized using the titanium-based catalyst. The method by heat degradation is preferable because a propylene-based polymer having the above-mentioned properties can be efficiently produced in high yield.

Examples of the method of heat degradation include a method of thermally decomposing a high molecular weight propylene-based polymer.
The following method is exemplified as a specific method. 1) A method in which a high-molecular-weight propylene-based polymer is fed to a single-screw or twin-screw extruder, extruded while being melt-kneaded, and heated and degraded. 2) A high-molecular-weight propylene-based polymer is subjected to a tubular reactor or a tank-type reaction. 3) Method of supplying high-molecular-weight propylene-based polymer to an extruder, extruding it continuously while melting and kneading it, and supplying it to a tubular reactor for heat-degradation.

The heating temperature in the extruder or reactor is 3
The temperature is from 00 to 460 ° C, preferably from 350 to 450 ° C.
In the above method, the method 3) is preferable. Further, it is preferable to perform the heat degradation under an inert atmosphere such as nitrogen.

After the heat degradation, it is preferable to filter through a filter such as a glass filter having a mesh size of about 1 μm. Filtration removes foreign substances and particles having a large particle size, and can obtain a propylene-based polymer in which magnesium metal or a magnesium compound is more uniformly dispersed.

As the propylene polymer constituting the release agent of the present invention, a modified product graft-modified with a modifying agent such as an aromatic vinyl compound or an unsaturated carboxylic acid can be used. The graft amount of the above modifier in the graft modified product is 0.5 to 60% by weight, preferably 1 to 60% by weight.
It is desirably about 15% by weight.

Examples of the aromatic vinyl compound for graft modification include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene,
2,5-dimethylstyrene, 3,4-dimethylstyrene, 2,4,6-trimethylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-butylstyrene, 4-
sec-butylstyrene, 4-t-butylstyrene,
-Hexylstyrene, 4-nonylstyrene, 4-octylstyrene, 4-phenylstyrene, 4-decylstyrene, 4-dodecylstyrene, 2-chlorostyrene, 3-
Chlorostyrene, 4-chlorostyrene, 2,4-dichlorostyrene, 3,4-dichlorostyrene, 2-methoxystyrene, 4-methoxystyrene, 4-ethoxystyrene and the like can be mentioned.

As the unsaturated carboxylic acid compound for graft modification, methyl acrylate, butyl acrylate,
Sec-butyl acrylate, isobutyl acrylate, propyl acrylate, isopropyl acrylate, 2-octyl acrylate, dodecyl acrylate, stearyl acrylate, hexyl acrylate, isohexyl acrylate, phenyl acrylate, 2-chlorophenyl acrylate, Diethylaminoethyl acrylate, 3-acrylic acid
Acrylic esters such as methoxybutyl, diethylene glycol ethoxylate acrylate, and 2,2,2-trifluoroethyl acrylate; methyl methacrylate, ethyl methacrylate, butyl methacrylate, methacrylic acid s
ec-butyl, isobutyl methacrylate, propyl methacrylate, isopropyl methacrylate, methacrylic acid 2
-Octyl, dodecyl methacrylate, stearyl methacrylate, hexyl methacrylate, decyl methacrylate,
Methacrylates such as phenyl methacrylate, 2-chlorophenyl methacrylate, diethylaminoethyl methacrylate, 2-ethylhexyl methacrylate, 2,2,2-trifluoroethyl methacrylate; ethyl maleate, propyl maleate, and butyl maleate And maleic esters such as diethyl maleate, dipropyl maleate and dibutyl maleate; fumaric esters such as ethyl fumarate, butyl fumarate and dibutyl fumarate; ethyl itaconate, diethyl itaconate and butyl itaconate And itaconic esters.

As the graft modification method, various known methods can be employed. For example, a method in which a propylene-based polymer and a modifier are heated and melt-mixed and reacted in the presence of a radical initiator can be used. The reaction temperature at that time is preferably in the range of 125 to 325 ° C., and the radical initiator used is benzoyl peroxide, lauroyl peroxide, dicumyl peroxide,
Peroxides such as di-t-butyl peroxide; and azo compounds such as azobisisobutyronitrile.

The electrostatic toner of the present invention is a toner containing the above-mentioned release agent for an electrostatic toner, and a binder resin and a colorant are usually compounded in the electrostatic toner. The binder resin is a resin capable of maintaining a formed image for a long period of time by fixing a colorant on paper or a film, and has good chargeability, fixing property, and miscibility with a colorant, and is suitable. Softening point (1
Any resin can be used as long as it has a temperature of around (00 ° C.) and is not particularly limited. As such a resin, a thermoplastic resin conventionally used for an electrostatic toner, or a resin having substantially the same properties as these can be used.

Specific examples of the binder resin include, for example, a styrene polymer, a ketone resin, a maleic acid resin, an aliphatic polyester resin, a polyester aromatic resin, a coumarone resin, a phenol resin, an epoxy resin, a terpene resin, and a polyvinyl resin. Butyral, polybutyl methacrylate, polyvinyl chloride, polyethylene, polypropylene,
Amorphous resins such as polybutadiene and ethylene / vinyl acetate copolymer are exemplified. These binder resins can be used alone or in combination of two or more. Among the above binder resins, a styrene polymer is preferable because it has an appropriate softening point of about 100 ° C. and shows good fixability.

The styrene-based polymer includes, for example, a homopolymer or a copolymer comprising only a styrene-based monomer, and a copolymer of a styrene-based monomer and another vinyl-based monomer. Can be Examples of the styrene monomer include styrene, p-chlorostyrene, and vinyl naphthalene.

Examples of the other vinyl monomers include ethylenically unsaturated monoolefins such as ethylene, propylene, 1-butene and isobutene; and vinyl halides such as vinyl chloride, vinyl bromide and vinyl fluoride. Vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate and vinyl butyrate; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, n-octyl acrylate, dodecyl acrylate,
2-chloroethyl acrylate, phenyl acrylate, α
Esters of α-methylene aliphatic monocarboxylic acids such as methyl chloroacrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate; nitriles or amides such as acrylonitrile, methacrylonitrile, acrylamide; vinyl methyl ether, vinyl Vinyl ethers such as ethyl ether, vinyl propyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl And N-vinyl compounds such as pyrrolidone. Among these vinyl monomers, esters of α-methylene aliphatic monocarboxylic acid are preferred.

The styrene polymer preferably has a number average molecular weight (Mn) of 2,000 or more, and particularly preferably has a number average molecular weight (Mn) of 3,000 to 30,000. The styrene polymer preferably has a styrene content of 25% by weight or more.

The colorant incorporated in the electrostatic toner of the present invention is not particularly limited as long as it forms a visible image fixed on paper or a film and does not fade for a long time.
Any of them can be used, and coloring agents conventionally used in electrostatic toners or coloring agents similar thereto can be used.

Specific examples of the coloring agent include, for example, carbon black, phthalocyanine blue, aniline blue, alcohol oil blue, chrome yellow, ultramarine blue, quinoline yellow, lamp black, rose bengal, diazo yellow, rhodamine B lake, Pigments or dyes such as carmine 6B and quinacridone derivatives. These can be used alone or in combination of two or more.

As the colorant, oil-soluble dyes such as azine-based nigrosine, indulin, azo-based dyes, anthraquinone-based dyes, triphenylmethane-based dyes, xanthene-based dyes, and phthalocyanine-based dyes are used for the purpose of complementary colors and charge control. You may mix.

In the electrostatic toner of the present invention, the mixing ratio of the release agent for the electrostatic toner, the binder resin and the colorant is usually such that the ratio of release agent / binder resin / colorant is expressed by weight ratio ( 1-2
0) / 100 / (1-20), preferably about (1-10) / 100 / (1-10).

The electrostatic toner of the present invention may contain other components in addition to the releasing agent for the electrostatic toner, the binder resin, and the colorant as long as the effects of the present invention are not impaired. For example, other components such as a charge control agent, a plasticizer, and a release agent such as another wax may be appropriately compounded.

The electrostatic toner of the present invention can be used as any one of a two-component electrostatic toner and a one-component electrostatic toner. When the electrostatic toner of the present invention is used as a two-component electrostatic toner, in order to manufacture the two-component electrostatic toner, first, the release agent for the electrostatic toner, the binder resin, the coloring agent, and The other components to be blended are melt-kneaded using a Banbury mixer or the like, or mixed by a known method using a ball mill, an attritor or the like, and then kneaded using a heating two-roll, heating kneader, extruder, or the like. , Then solidify by cooling. Next, the obtained solidified product is crushed using a hammer mill, crusher, or the like, or without crushing, finely crushed by a jet mill, a vibration mill, or by adding water and a ball mill, an attritor, or the like. A method in which a carrier is added to a material having an average particle size of 5 to 35 μm to prepare a two-component system, or the like can be employed. As the carrier, known carriers can be used without any particular limitation, and examples thereof include silica sand, glass beads, iron balls having a particle size of 200 to 700 μm, and powders of magnetic materials such as iron, nickel, and cobalt.

The amount of the release agent for the electrostatic toner in the two-component electrostatic toner is 1 to 20 parts by weight, preferably 2 to 10 parts by weight, per 100 parts by weight of the thermoplastic resin including the binder resin. It is an amount that becomes a ratio by weight.

When the electrostatic toner of the present invention is used as a one-component electrostatic toner, the one-component electrostatic toner may include a releasing agent for the electrostatic toner, a binder resin, a colorant, and The other components to be blended, the other thermoplastic resin and the magnetic material powder can be treated according to the same method as in the preparation of the two-component electrostatic toner to prepare a one-component system without adding a carrier.

The compounding amount of the release agent for the electrostatic toner in the one-component electrostatic toner is 1 to 20 parts by weight, preferably 1 to 10 parts by weight based on 100 parts by weight of the binder resin. .

As the magnetic material powder to be mixed with the one-component electrostatic toner, a fine powder of magnetite having a particle diameter of 1 μm or less is usually used, but metals such as cobalt, iron, nickel and the like, alloys thereof, oxides , Ferrite, and a powder of a mixture thereof can also be used. The compounding amount of the magnetic material powder in this one-component electrostatic toner is:
The obtained electrostatic toner does not lower its electrical resistance, has good charge retention of the electrostatic toner, does not cause image bleeding, and has a softening point in an appropriate range, so that fixing can be suitably performed. In addition, a required charge value is obtained, and scattering is difficult.
The amount is such that the proportion of the magnetic material powder is 40 to 120 parts by weight with respect to parts by weight. If necessary, a known charge control agent may be added to the two-component electrostatic toner or the one-component electrostatic toner.

[0057]

The release agent for an electrostatic toner of the present invention comprises a specific propylene-based polymer containing a specific amount of magnesium metal or a magnesium compound. By doing so, it is possible to obtain an electrostatic toner having excellent releasability at the time of thermal fixing, particularly at the time of low-energy fixing, and excellent blocking resistance, fixing properties and pigment dispersibility, and furthermore, an offset phenomenon is caused. In addition, it is possible to stably obtain an electrostatic toner which does not cause a filming phenomenon by preventing contamination of a carrier, a photoreceptor, a heating roll and the like, and does not cause disturbance of an image. Since the electrostatic toner of the present invention contains the above-described release agent for electrostatic toner, it has excellent releasability at the time of heat fixing, particularly excellent releasability at the time of low energy fixing, and has anti-blocking properties, fixing properties and It is excellent in pigment dispersibility, does not cause an offset phenomenon, and prevents contamination of a carrier, a photoreceptor, a heating roll and the like, does not cause a filming phenomenon, and does not cause image disorder.

[0058]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to examples and comparative examples of the present invention, but these examples do not limit the scope of the present invention in any way.

Example 1 << Production of Propylene Polymer (PW-1) >> High-molecular-weight propylene / ethylene copolymer [Mg (OC ₂ H ₅ ) ₂ , titanium tetrachloride using propylene and ethylene as monomers; And MgCl ₂ -supported titanium catalyst obtained by reacting di-n-butyl phthalate in toluene, and a propylene / ethylene copolymer polymerized in the presence of triethylaluminum. The polymerization step does not have a decatalyst treatment step (deashing step). Melt index 2
0 g / 10 min, propylene content 95 mol%, melting point 139
° C, hereinafter abbreviated as PO-1. Is supplied to a twin-screw extruder (screw diameter 30 mmφ), and the screw rotation speed is 25 rpm.
m and then heated and degraded at 400 ° C. to produce a propylene / ethylene copolymer wax (hereinafter PW-
1). Table 1 shows the properties of PW-1.

The weight average molecular weight, melting point, and composition distribution (CMn / CMw) were measured by the following methods. << Weight average molecular weight >> The measurement was carried out using GPC150C manufactured by Waters Co., at a temperature of 140 ° C, a solvent o-dichlorobenzene, and a measurement flow rate of 1.0 ml / min at a concentration of 0.1 wt%. In calculating the molecular weight of the sample, a calibration curve prepared from a monodisperse polystyrene standard sample was used. As a column, GMH-HT manufactured by Tosoh Corporation (60 cm, trademark)
And GMH-HTL (60 cm, trademark) were used.

<< Melting Point >> Using a differential scanning calorimeter (DSC), the sample was heated to 200 ° C. and kept for 10 minutes, then lowered to 30 ° C. at an overheating rate of 10 ° C./min and kept for 5 minutes. Thereafter, the temperature was raised at a rate of 10 ° C./min, and the endothermic peak observed at this time was taken as the melting point.

<< Composition Distribution (CMn / CMw) >> A sample having a concentration of 0.1 wt% was prepared using o-dichlorobenzene as a solvent. Using this sample as a column, GP using GMH-HT (60 cm, trademark) manufactured by Tosoh Corporation
C apparatus (using an oven of a heating and eluting fractionation apparatus manufactured by Tosoh Corporation) at a temperature of 140 ° C. and a measured flow rate of 1.0 ml / m.
The molecular weight fractionation was performed under the conditions of “in”, and while the obtained molecular weight fractionated sample was continuously passed through a flow cell, the ethylene content was continuously measured by a Fourier transform infrared spectrophotometer (FT-IR). GPC obtained by this measurement
The chromatogram shows that the average ethylene content (CMn) and the weight average molecular weight (Mn) near the number average molecular weight (Mn)
w) The average ethylene content (CMw) in the vicinity is determined, and CM
The ratio of n / CMw was determined. In calculating the molecular weight, a calibration curve prepared from a monodisperse polystyrene standard sample was used.

<< M in the propylene-based polymer (PW-1)
Determination of g content >> Plasma emission spectroscopy (ICP) was used. Pretreatment: Put 10 g of a sample in a platinum dish and place it in an electric furnace (6
(00 ° C, 2 hours). Melting agent (KH
1 g of SO ₄ ), and after cooling, the volume was increased to 20 ml of 6N nitric acid to obtain a measurement solution. Measurement: Shimadzu Corporation; ICPS-8000 (trademark) used Plasma source; Argon gas Other conditions conformed to the standard conditions of the apparatus

<< Preparation of Electrostatic Toner >> A styrene / n-butyl methacrylate copolymer (manufactured by Sanyo Kasei Kogyo Co., Ltd., Hymer SEM-73F, trademark) 85 parts by weight, and PW-1 was 4 parts by weight.
Parts by weight, 9 parts by weight of carbon black (manufactured by Mitsubishi Kasei Kogyo Co., Ltd., Diamond Black SH, trademark) and a metal-containing dye (BASF
2 parts by weight of Pomelo Fast Black B (trademark) manufactured by the company were supplied to a ball mill and mixed for 24 hours. Next, the mixture was kneaded with a hot roll, cooled, pulverized and classified to obtain an average particle size of 1
A developing material of 0 to 13 μm was prepared. With respect to 120 parts by weight of this developer, an average particle size of 50 to 80 μm was used as a carrier.
m of iron powder was blended at a ratio of 100 parts by weight to prepare a two-component electrostatic toner. Using this two-component electrostatic toner,
A copy test was performed by the following method. Table 2 shows the results.

<< Fixing Property of Fixed Image >> Using a two-component electrostatic toner, a test image is copied and developed on a selenium photoreceptor by electrophotography, and the obtained image is transferred to transfer paper.
A fixing roller having a surface made of polytetrafluoroethylene (manufactured by DuPont) and a silicone rubber KE-1 having a surface
Using a pressure roller formed of 300RTV (trademark, manufactured by Shin-Etsu Chemical Co., Ltd.), the temperature of the fixing roller was set to 200 ° C.
To fix the image. Then, on the obtained fixed image, the bottom surface with a load of 500 g was 15 mm × 7.5 m.
m, and the optical reflection density was measured with a Macbeth reflection densitometer before and after that, and the fixability of the fixed image was calculated by the following formula. Fixability (%) = (image density after test) / (image density before test) × 100

<< Blocking Resistance of Electrostatic Toner >> 100 g of a two-component electrostatic toner was placed in a resin container, allowed to stand at 60 ° C. for 50 hours after tapping, returned to room temperature, and checked for blocking. The state of blocking was visually determined according to the following evaluation criteria. ◎: Not blocking at all ：: Slightly loosened by hand and slightly blocked △: Quite a lot of blocking easily broken by hand ×: Many lumps that cannot be completely loosened by hand

<< Offset Phenomenon, Image Disturbance, and Contamination of Photoconductor and Heating Roller >> A test image was copied and developed on a selenium photoconductor by electrophotography using a two-component electrostatic toner. The image is transferred to a transfer paper, and a fixing roller of 200 ° C. formed on the surface with polytetrafluoroethylene (manufactured by DuPont) and a silicone rubber KE formed on the surface
Using a pressure roller formed of -1300 RTV (trademark, manufactured by Shin-Etsu Chemical Co., Ltd.), a copying process for fixing an image was repeated. After repeating the copying process 5000 times,
The presence / absence of the offset phenomenon, the presence / absence of image disturbance, and the contamination of the photoreceptor / fixing roller surface were examined. The presence / absence of the offset phenomenon and the presence / absence of image disorder were visually determined according to the following evaluation criteria. ：: No problem at all 極: Offset phenomenon or image disturbance occurs very slightly ×: Offset phenomenon or image disturbance is quite severe

The contamination of the photoreceptor and the fixing roller was visually determined according to the following evaluation criteria. ◎: Not dirty at all ○: Very little stain is seen ×: Very dirty

<< Filming to Carrier >> The two-component electrostatic toner was mixed at 50 rpm for 1 hour with a tumbler mixer, and the amount of toner adhering to the carrier surface was observed with a microscope. ◎: Almost no adhesion ○: Slight adhesion is observed ×: Considerable adhesion

Example 2 High molecular weight propylene / ethylene copolymer (PO-1)
Was heated and degraded at 425 ° C. in the same manner as in Example 1 to obtain a propylene / ethylene copolymer wax (PW-
2) was manufactured. Table 1 shows the properties of PW-2. next,
An electrostatic toner was prepared and a copy test was performed in the same manner as in Example 1 except that PW-2 was used instead of PW-1. Table 2 shows the results.

Example 3 High molecular weight propylene / ethylene copolymer (PO-1)
Of propylene / ethylene copolymer wax (PW-
3) was manufactured. Table 1 shows the properties of PW-3. next,
An electrostatic toner was prepared and a copy test was performed in the same manner as in Example 1 except that PW-3 was used instead of PW-1. Table 2 shows the results.

Comparative Example 1 << Production of Propylene Copolymer (PW-4) >> A high molecular weight propylene / ethylene copolymer was polymerized by the following procedure. Using propylene and ethylene as monomers, in the presence of a titanium catalyst in which titanium trichloride and an electron donor are mixed (catalyst component molar ratio is TiCl ₃ / Et ₂ AlCl =
0.2) was copolymerized. The polymerization temperature was 60 ° C., the pressure was 10.5 kg / cm ² , and the catalyst concentration was 200 g of (C ₂ H ₅ ) ₂ AlCl in 1 liter of hexane.
After the polymerization, the following decatalyst treatment was carried out.

<< Decatalyst Treatment >> After the polymerization, 20 ml of isopropyl alcohol was added to the polymerization solution to stop the catalytic activity.
Pour this on a Buchner funnel and add 0.5 liter of hexane.
And dried at 50 ° C. under reduced pressure. The obtained polymer had a melt index of 20 g / 10 minutes, a propylene content of 95 mol%, and a melting point of 139 ° C. (hereinafter PO-
2).

The polymer was supplied to a twin-screw extruder (screw diameter 3
0 mmφ), and is heated and degraded at 400 ° C. while extruding at a screw rotation speed of 25 rpm.
An ethylene copolymer wax was produced (hereinafter abbreviated as PW-4). Table 1 shows the properties of PW-4. Next, PW-1
In place of PW-4, an electrostatic toner was prepared and a copy test was performed in the same manner as in Example 1. Table 2 shows the results.

Comparative Example 2 High molecular weight propylene / ethylene copolymer (PO-2)
Was heated and degraded at 425 ° C. in the same manner as in Example 1, except that propylene / ethylene copolymer wax (PW-
5) was produced. Table 1 shows the properties of PW-5. next,
An electrostatic toner was prepared in the same manner as in Example 1 except that PW-5 was used instead of PW-1, and a copy test was performed. Table 2 shows the results.

Comparative Example 3 High molecular weight propylene / ethylene copolymer (PO-2)
Was heated and degraded at 390 ° C. in the same manner as in Example 1, except that propylene / ethylene copolymer wax (PW-
6) was manufactured. Table 1 shows the properties of PW-6. next,
An electrostatic toner was prepared and a copy test was performed in the same manner as in Example 1 except that PW-6 was used instead of PW-1. Table 2 shows the results.

[0077]

[Table 1]

[0078]

[Table 2]

Claims (5)

[Claims] 1. The method according to claim 1, wherein the magnesium metal or magnesium compound is 1 to 100 parts by weight as magnesium atom.
Contains 00 ppm, propylene content is 90 mol% or more,
The weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) is 3000 to 50
000, a release agent for electrostatic toner comprising a propylene-based polymer having a melting point of 120 to 140 ° C. measured by a differential scanning calorimeter (DSC). 2. The release agent for an electrostatic toner according to claim 1, wherein the magnesium metal or the magnesium compound is derived from a polymerization catalyst. 3. The method according to claim 1, wherein the magnesium metal or the magnesium compound is a magnesium metal or a magnesium compound,
3. The release agent for an electrostatic toner according to claim 1, wherein the release agent is derived from a solid titanium catalyst component comprising a titanium compound and an electron donor. 4. A polymer in which a propylene-based polymer is polymerized using a titanium-based catalyst containing a solid titanium catalyst component comprising magnesium metal or a magnesium compound, a titanium compound and an electron donor, and the catalyst is not removed after the polymerization. 4. The release agent for an electrostatic toner according to claim 1, wherein the release agent is a polymer obtained by heating and degrading the polymer. 5. An electrostatic toner comprising the release agent for an electrostatic toner according to claim 1.