JP2747538B2 - Release agent for toner and resin composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a release agent for an electrophotographic toner and a resin composition for an electrophotographic toner. More specifically, the present invention relates to a toner release agent and a toner resin composition used in a heat fixing type copying machine or printer having excellent hot offset resistance and fluidity.

[Related Art] A toner of a heat fixing system is fixed on a support by a heat roll. At this time, it is desired that the lower limit fixing temperature (hereinafter abbreviated as MF) is low. On the other hand, when the temperature of the roll increases, a phenomenon that the toner sticks to the roll appears. It is desired that the temperature at which this offset occurs (hereinafter abbreviated as HO) is high.

Generally, HO increases as the molecular weight of the binder increases and the glass transition point (hereinafter abbreviated as Tg) increases, but at the same time,
MF will also be higher. Conversely, when the molecular weight decreases, both MF and HO decrease.

As a method for satisfying the contradictory required properties, a method is known in which a release agent is added to a binder to increase HO without increasing MF. Conventionally, as such a release agent, low molecular weight polypropylene and the like are known. (For example, JP-B-52-3304).

[Problems to be Solved by the Invention] However, the conventional release agent has a low melt viscosity in order to increase the HO. However, the toner using this release agent has a low fluidity, and furthermore, the There is a problem such as an increase in the amount of filming material attached, and a release agent that satisfies both the hot offset resistance (high HO) and the fluidity of the toner has not been obtained.

[Means for Solving the Problems] The present inventors have conducted intensive studies on a release agent for toner and a binder composition having excellent hot offset resistance and fluidity, and have reached the present invention.

That is, the present invention has a melt viscosity at 160 ° C. of 1000 cps.
The maximum value is substantially one in a chromatogram by gel permeation chromatography (hereinafter abbreviated as GPC), and the ratio of the weight average molecular weight to the number average molecular weight is 2.9: 1.0 to 3.8: 1.0. A release agent for an electrophotographic toner comprising a certain low molecular weight polypropylene resin; and a resin composition for an electrophotographic toner comprising a thermoplastic resin binder and the above release agent.

In the present invention, the melt viscosity at 160 ° C. can be measured using a Brookfield-type rotational viscometer. Conditions other than the measurement temperature may be performed according to JIS-K1557-1970. An oil bath with a temperature regulator can be used for adjusting the temperature of the measurement sample. The melt viscosity at 160 ° C. of the low molecular weight polypropylene resin is usually 1
It is 000 cps or less, preferably 500 cps or less. If it exceeds 1000 cps, the releasing performance of the toner becomes insufficient.

In the present invention, examples of the low-molecular-weight polyprolene-based resin include, for example, low-molecular-weight polymers of propylene alone, low-molecular-weight copolymers of propylene and other olefins, and high-molecular-weight polypropylene-based resins that are thermally degraded (mainly by heat). Cutting the chain to reduce the molecular weight; this expression will be used hereinafter).

In order to enhance the releasing effect of the toner, it is usually preferable that the molecular weight of the low molecular weight polypropylene resin is as small as possible, but as the molecular weight decreases, the fluidity of the toner decreases, and the amount of filming material attached to the carrier increases. .

The cause of the fluidity inhibition of the toner or the adhesion of the filming substance to the carrier is a low molecular weight component that is liquid at room temperature generated by reducing the molecular weight of the low molecular weight polypropylene resin. The present inventors have found that the use of a low-molecular-weight polypropylene resin having a small amount of (a maximum value is substantially one in chromatograph by GPC) as a mold release agent dramatically improves fluidity. Was.

That is, the low-molecular-weight polypropylene resin in the present invention has substantially one maximum value in a chromatograph by GPC.

Examples of the method for producing a low-molecular-weight polypropylene resin in which the maximum value is substantially one in the chromatograph by GPC are as follows: 1) A high-molecular-weight polypropylene resin is produced at room temperature under the condition that by-product of a low-molecular-weight liquid is small. 2) decompressing the low molecular weight polypropylene resin while heating,
A method of distilling off a low-molecular-weight substance which is liquid at room temperature; and 3) a method of extracting a low-molecular-weight polypropylene resin with a solvent.

Although the production method is not particularly limited, 1) or 2) is preferable for simplifying the production process.

When the high molecular weight polypropylene resin of 1) is produced by thermal degradation, the high molecular weight polypropylene as a raw material usually has a melt index (hereinafter abbreviated as MI) of 0.1 to 1.
00, preferably 1 to 50. Those with an MI of over 100 are practically difficult to obtain. Also, if the MI is less than 0.1, it is difficult to reduce the molecular weight. The high molecular weight polypropylene resin used as a raw material may be a propylene homopolymer or a copolymer of propylene and another olefin. Other olefins include ethylene, butene,
Examples thereof include those having 2 and 4 to 8 carbon atoms, such as octene. In the case of the copolymer, the content of the other olefin is usually 25% by weight or less, preferably 10% by weight or less. If it exceeds 25% by weight, the releasing performance of the toner becomes insufficient.

As a specific example of the method of thermal degradation, a high-molecular-weight polypropylene-based resin as a raw material is introduced into a tubular reactor in which the manner of applying heat is made as uniform as possible, for example, a reactor incorporating a stirrer such as a static mixer, 300 ~ 500 ℃
There is a method of obtaining a material having the maximum value of substantially one by passing the solution for 0.1 to 3 hours. In this method, the molecular weight of the thermal degradation product can be adjusted by the thermal degradation temperature and the thermal degradation time. If the temperature is lower than 300 ° C., it takes a long time to reduce the molecular weight, and if it exceeds 500 ° C., the molecular weight is reduced in a short time, and it is difficult to control the molecular weight.

As a specific example of the method 2), there is a method in which a low-molecular-weight polypropylene is heated to 150 to 300 ° C. and reduced to a pressure of 300 mmHg or less to obtain one having the maximum value of substantially one. it can. The amount to be distilled off can be adjusted by the heating temperature and the degree of reduced pressure.

As a specific example of the method 3), methyl ethyl ketone (hereinafter abbreviated as MEK) is added to powder of low molecular weight polypropylene, and the mixture is heated under reflux with stirring, cooled to room temperature, and then dried.
An example is a method of separating and removing the MEK-soluble matter and drying the MEK-insoluble matter to obtain the one having the maximum value of substantially one. In this method, if the amount of MEK is large and the reflux heating time is long, the extraction can be performed more completely, but the production efficiency decreases. The weight ratio of low molecular weight polypropylene to MEK is usually 1.0: 0.5 to 1.0: 1.
0.0, and the reflux heating time is usually 1 to 5 hours. Solvents other than MEK include ether solvents such as dioxane and tetrahydrofuran (hereinafter abbreviated as THF), alcohol solvents such as methanol and ethanol, aromatic solvents such as toluene and xylene, and chlorine solvents such as chloroform and carbon tetrachloride. , And mixtures thereof.

Chromatography with GPC can be measured under the following conditions.

Apparatus: GPC-150C manufactured by Waters Column: Shodex KF-80M (manufactured by Showa Denko) Measurement temperature: 135 ° C Sample solution: 0.3% by weight of trichlorobenzene solution Solution injection amount: 0.4 ml Detector: Refractive index detector In the present invention, the ratio of the weight average molecular weight and the number average molecular weight of the low molecular weight polypropylene resin obtained by conversion with standard polystyrene is 2.9: 1.0 to 3.8: 1.0, preferably
2.9: 1.0 to 3.5: 1.0.

If the ratio of the weight average molecular weight to the number average molecular weight exceeds 3.8: 1.0, the releasing performance of the toner becomes insufficient, or the fluidity of the toner decreases and the amount of the filmed material adhered to the carrier increases.

Those having a ratio of the weight average molecular weight to the number average molecular weight of less than 2.9: 1.0 are substantially difficult to obtain.

Softening point (ring and ball softening point, hereinafter abbreviated as SP) is usually 120 to 1
80 ° C.

The release agent of the present invention can be used in addition to other components such as a thermoplastic resin binder at the time of toner production, or can be used in a form kneaded and mixed in advance with the thermoplastic resin binder.

In the present invention, examples of the thermoplastic resin binder include a styrene resin, a polyester resin, and a composite thereof.

Examples of the styrene resin include a monofunctional styrene monomer, a (meth) acrylic monomer, and a resin obtained by polymerizing another monofunctional or polyfunctional monomer as required using a polymerization initiator.

Examples of the styrene-based monomer include styrene and alkylstyrene (for example, α-methylstyrene, p-methylstyrene). Preferred of these are:
It is styrene.

(Meth) acrylic monomers include alkyl (meth) acrylate [alkyl having 1 to 18 carbon atoms, such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth). Acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, etc.], hydroxyl group-containing (meth) acrylate [hydroxyethyl (meth) acrylate, etc.], amino group-containing (meth)
Examples include acrylates [dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, etc.], nitrile group-containing (meth) acrylic compounds [acrylonitrile, etc.], (meth) acrylic acid and the like. Preferred among these are alkyl (meth) acrylates, and particularly preferred are methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate (meth) acrylic acid and It is a mixture of two or more of these.

Examples of other monomers include vinyl esters (eg, vinyl acetate, vinyl propionate, etc.) and aliphatic hydrocarbon monomers (eg, butadiene).

Examples of the polyfunctional monomer include divinylbenzene, divinyltoluene, ethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and di (meth) acrylate of an adduct of bisphenol A with ethylene oxide. be able to.

If a multifunctional monomer is used, preference is given to divinylbenzene and 1,6-hexanediol acrylate.

The amounts (% by weight) of these monomers are as follows.
The styrenic monomer is usually 50 to 90%, preferably
60-80%. (Meth) acrylic monomer is usually 50
1010%, preferably 40-20%. Other monomers are usually at most 10%, preferably at most 5%. The polyfunctional monomer content is usually 5% or less, preferably 3% or less. When the amount of the styrene monomer exceeds 90% and the amount of the (meth) acrylic monomer is less than 10%, the MF of the toner increases, and when the amount of the styrene monomer is less than 50% and the amount of the acrylic monomer becomes 50%. %, The HO becomes low and the blocking property of the toner becomes poor. When the amount of the polyfunctional monomer exceeds 5%, the MF increases.

The polymerization of the styrenic resin exemplified above is usually carried out by solution polymerization or suspension polymerization, but solution polymerization is preferred.

In the case of solution polymerization, aromatic hydrocarbon solvents (toluene, xylene, etc.), chlorine solvents (chloroform, carbon tetrachloride, ethylene dichloride, ethylene tetrachloride, etc.), ether solvents, and two or more of these solvents are used as the solvent. Of mixed solvents. The amount of the solvent to be used is generally 1,000% or less, preferably 400% or less, based on the total weight of the monomers.
When the amount of the solvent used exceeds 1,000%, the production efficiency decreases.

A polymerization initiator is usually used for the polymerization. Examples of the polymerization initiator include an azo initiator (azobisisobutyronitrile, azobisisovaleronitrile, etc.) and a peroxide initiator (benzoyl peroxide, lauroyl). Peroxide, di-tert.-butyl peroxide, tert.-butylcumyl peroxide, dicumyl peroxide,
tert.-butylperoxybenzoate, 1,1-bis (te
rt.-butylperoxy) 3,3,5-trimethylcyclohexane and the like.

The polymerization reaction is usually performed under an atmosphere of an inert gas such as nitrogen. The polymerization temperature is usually 50 to 250 ° C, preferably 70 to 230
° C. When the temperature is lower than 50 ° C., the initiation ability of the polymerization initiator becomes low. If the temperature exceeds 250 ° C., the decomposition of the polymer becomes remarkable. The reaction time depends on other conditions, but is usually 1 to 50 hours, preferably 2 to 10 hours. If the reaction time is shorter than 1 hour, it is often difficult to control the reaction.
Beyond time is economically disadvantageous. The solvent used for the polymerization is removed after the polymerization. The desolvation is performed under normal pressure or reduced pressure.

The molecular weight of the styrenic resin according to the present invention is usually 5,000.
0-1,000,000, preferably 10,000-400,000, Tg
Is usually from 40 to 80 ° C, preferably from 45 to 70 ° C. Tg is 40 ℃
If the temperature is lower than 80 ° C, the storage stability of the toner becomes poor, and
If the ratio exceeds MF, the MF becomes high and the toner cannot be put to practical use. The molecular weight of the styrene resin can be measured by GPC under the following conditions.

Apparatus: HLC-802A manufactured by Toyo Soda Column: TSK gel GMH6 (manufactured by Toyo Soda) Measurement temperature: 40 ° C Sample solution: 0.5% by weight THF solution Solution injection volume: 200 μl Detector: Refractive index detector Molecular weight calibration: Standard polystyrene Criteria Examples of the polyester-based resin include, for example, polycondensates of a polyhydric alcohol and a polybasic acid.

Polyhydric alcohols include (1) ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol,
1,4-butanediol, neopentyl glycol, 1,6-
Aliphatic glycols such as hexanediol and their alkylene oxides [ethylene oxide (hereinafter referred to as
EO), propylene oxide (hereinafter abbreviated as PO), etc.] adducts; (2) hydroquinone, catechol, resorcinol, pyrogallol, bisphenols (such as bisphenol A, bisphenol F, bisphenol sulfone) and hydrogenated bisphenols and alkylene oxides (3) glycerin, trimethylolpropane, trimethylolethane, hexanetriol, pentaerythritol, diglycerin, α-methylglucoside, sorbitol, xylitol, mannitol Trihydric alcohols such as glucose, fructose, and sucrose, and alkylene oxide adducts thereof; (4) alkanolamines (such as triethanolamine and tripropanolamine); Etc.), alkylenediamine (C2-C6) [ethylenediamine, hexamethylenediamine, etc.], polyalkylene (C2-C2 of alkylene)
6) Polyamines [diethylenetriamine, triethylenetriamine, etc.], aromatic amines (aniline, phenylenediamine, diaminotoluene, xylylenediamine,
Methylene dianiline, diethyl tolylene diamine, diphenyl ether diamine, etc.), alicyclic amines (isophorone diamine, cyclohexyl methane diamine, cyclohexylene diamine, etc.), heterocyclic amines (piperazine, aminoethyl piperazine, etc.)
Alkylene oxide (EO)
And / or PO) added amino group-containing polyhydric alcohols and mixtures of two or more thereof.

Preferred among these are ethylene glycol,
Alkylene oxide is added to neopentyl glycol and bisphenols (especially bisphenol A) in 2-3
Molar additions and mixtures of two or more of these are preferred, with particular preference given to 2-3 mols of alkylene oxide of bisphenol A, neopentyl glycol and mixtures of two or more of these.

Examples of polybasic acids include (1) succinic acid, maleic acid, fumaric acid, itaconic acid, azelaic acid, mesaconic acid, citraconic acid, sebacic acid, glutaconic acid, adipic acid, malonic acid, phthalic acid, isophthalic acid, terephthalic acid, Dibasic acids such as cyclohexanedicarboxylic acid, octylsuccinic acid and dodecenylsuccinic acid; (2) trimellitic acid, 1,2,4-cyclohexanedicarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-butane Tricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, pyromellitic acid, benzophenonetetracarboxylic acid, cyclopentadienetetracarboxylic acid, tetra (methylenecarboxyl) Methane, 1,2,7,8
Tribasic or higher polybasic acids such as octanetetracarboxylic acid; and anhydrides and lower alkyl esters of these acids. In addition, polymerized fatty acids such as dimer and trimer of linoleic acid can be used.

Among these, succinic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, octylsuccinic acid, and alkyl or alkenyl (C4-18) succinic acids represented by octylsuccinic acid are preferred.

As the polyester resin exemplified above, a linear resin is preferable, but a tri- or higher alcohol such as trimethylolpropane and / or a tri- or higher polybasic acid such as trimellitic acid is used in a small amount (polyhydric alcohol). And usually 1 to 30 mol%, preferably 2 to 10 mol% in the polybasic acid)
A branched type obtained by using the same can also be used.
In addition to polyhydric alcohols and polybasic acids, hexamethylene diamine, amide bond-containing polyester produced using a small amount of polyamines such as methylene diamine,
It can be used as the polyester according to the present invention.

The molar ratio between the polyhydric alcohol and the polybasic acid is usually 1.0: 1.3 to 1.0: 0.7, preferably 1.0: 1.2 to 1.0: 0.8 for the dihydric alcohol and the dibasic acid.

The polyesterification reaction is carried out, if necessary, in the presence of an esterification catalyst (for example, zinc oxide, stannous oxide, dibutyltin oxide, dibutyltin dilaurate, etc.), usually at 150 to 250 ° C.
At any given temperature. The reaction can be carried out under normal pressure or reduced pressure, and in the presence or absence of an inert gas or a solvent (eg, toluene, xylene, or the like).

The acid value and hydroxyl value of the polyester have a total value of 10
It is 0 or less, preferably 60 or less.

The Tg of this polyester resin is usually 40 to 80 ° C,
Preferably it is 45-70 ° C. If the Tg is lower than 40 ° C, the storage stability of the toner becomes poor.
And the toner cannot be put to practical use.

Examples of the composite system of a styrene-based resin and a polyester-based resin include: 1) a mixture of a styrene-based resin and a polyester-based resin uniformly; 2) a block or graft of a polyester-based resin with a styrene-based monomer and / or a (meth) acrylate monomer. 3) Blocked or grafted styrene resin and polyester resin.

When the release agent of the present invention is kneaded and mixed in advance with the above-mentioned thermoplastic resin-based binder and then used for toner production, the thermoplastic resin-based binder can be blended after being prepared, but the resin composition for electrophotographic toner is the present invention. It is more preferable that the release agent of the present invention is uniformly dispersed because a more excellent release effect can be obtained. Therefore, it is desirable that the release agent of the present invention is added to the system at the time of polymerization of the thermoplastic resin.

Examples of the formulation of the electrophotographic toner to be used for the binder of the present invention are as follows: A) Usually 50 to 95% of a thermoplastic resin-based binder, usually 1 to 30% of a release agent, and a known coloring based on the weight of the toner. Material (carbon black, iron black, benzidine yellow, quinacridone, rhodamine B, phthalocyanine, etc.) usually contains 5 to 10% and magnetic powder (ferromagnetic metal powder such as iron, cobalt, nickel, etc. or compounds such as magnetite, hematite, ferrite, etc.) ) Is usually 0 to 50%, B) The electrophotographic toner resin composition is usually 50 to 95%, the release agent is usually 0 to 30%, and a known coloring material (carbon black, Iron black, benzidine yellow,
A formulation containing usually 5 to 10% of quinacridone, rhodamine B, phthalocyanine and the like and usually 0 to 50% of a magnetic powder (a powder of a ferromagnetic metal such as iron, cobalt and nickel or a compound of magnetite, hematite and ferrite). No.

Furthermore, various additives (such as a lubricant (eg, polytetrafluoroethylene, low molecular weight polyolefin, fatty acid, or a metal salt or amide thereof) and a charge controlling agent (eg, nigrosine and quaternary ammonium salt)) can be included.

As an example of a method for producing an electrophotographic toner, the above-mentioned formulation A),
After dry-blending each component in B) and the various additives described above, the mixture is subjected to melt-kneading, coarse pulverization, pulverization using a jet pulverizer, or the like, and finally classified to finally obtain a particle size of 5%. A method for obtaining a toner of about 20 microns is exemplified.

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

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

[Examples] Hereinafter, the present invention will be further described with reference to examples, but the present invention is not limited thereto. In the examples, all parts are by weight.

Synthesis Example 1 Styrene 720 parts, 2-ethylhexyl acrylate 190
Parts and 60 parts of methyl methacrylate were polymerized in toluene using azobisisobutyronitrile as a polymerization initiator to obtain a thermoplastic resin binder (1). The Tg of the thermoplastic resin binder (1) was 61 ° C., the number average molecular weight was 11,000, and the weight average molecular weight was 300,000.

Example 1 Polypropylene (MI: 9, propylene homopolymer)
Is thermally degraded while continuously passing through a tube incorporating a static mixer, the melt viscosity at 160 ° C is 60 cps, and the maximum value is 1 in the chromatograph by GPC, the maximum molecular weight of which is 6000, weight The ratio of average molecular weight / number average molecular weight is
A low-molecular-weight polypropylene having a molecular weight of 3.5 was obtained, which was used as the release agent (1) of the present invention.

Example 2 In the same manner as in Example 1, the thermal degradation of polypropylene was carried out.
The melt viscosity at 200 ° C. is 200 cps, and the maximum value is one in the chromatograph by GPC, and the maximum molecular weight is 10,000,
A low-molecular-weight polypropylene having a weight-average molecular weight / number-average molecular weight ratio of 3.8 was obtained, which is referred to as a release agent (2) of the present invention.

Example 3 Except that the polypropylene of Example 1 was changed to an ethylene-propylene copolymer (J609H1000 manufactured by Ube Industries, ethylene content 6%), thermal degradation was performed in the same manner, and the melt viscosity at 160 ° C. was 7
In the chromatograph using 2 cps and GPC, the maximum value was one, and a low molecular weight polypropylene resin having a maximum molecular weight of 7000 and a ratio of weight average molecular weight / number average molecular weight of 3.7 was obtained. This is referred to as a release agent (3) of the present invention.

Example 4 An esterification reaction was carried out in a system comprising 302 parts of isophthalic acid and 480 parts of an EO2 molar adduct of bisphenol A, 31 parts of a release agent (3) and 1.6 parts of dibutyltin oxide to give an acid value of 45.0.
A resin composition (1) for an electrophotographic toner, which was a polyester having a hydroxyl value of 1.5, was obtained. The Tg of the resin composition (1) for electrophotographic toner was 63 ° C.

Example 5 Thermal degradation was performed while continuously passing the polypropylene used in Example 1 through a tube in which a static mixer was not incorporated. 1000 parts of the obtained low-molecular-weight polypropylene was heated and reduced to 300 ° C. and 10 mmHg in a reactor, and 50 parts of the liquid low-molecular-weight component was distilled off.The solution viscosity at 160 ° C. was 65 cps, and the maximum value was determined by chromatography with GPC. The maximum molecular weight is 6000, and the ratio of weight average molecular weight / number average molecular weight is
A low molecular weight polypropylene of 3.2 was obtained. This is referred to as the release agent (4) of the present invention.

Example 6 30 parts of release agent (4), 720 parts of styrene, 190 parts of 2-ethylhexyl acrylate and methyl methacrylate 6
Polymerization was carried out in toluene using 0 parts of azobisisobutyronitrile as a polymerization initiator to obtain a resin composition (2) for electrophotographic toner. Resin composition for electrophotographic toner (2)
Had a Tg of 61 ° C., a number average molecular weight of 11,000 and a weight average molecular weight of 300,000.

Example 7 The release agent (4) obtained in Example 5 was pulverized, and the powder thereof was obtained.
300 parts of methyl ethyl ketone was added to 100 parts, and the mixture was heated under reflux with stirring. After cooling to room temperature, the solvent was filtered off and dried.
The melt viscosity at 70 ° C. was 70 cps, and the maximum value was one in the gel permeation chromatography. The maximum molecular weight was 6,200, and the weight average molecular weight /
A low molecular weight polypropylene having a number average molecular weight ratio of 2.9 was obtained. This is designated as the release agent (5) of the present invention.

Example 8 A styrene-based resin was polymerized in the same manner as in Example 6 using the release agent (5) to obtain a resin composition (3) for electrophotographic toner.

Comparative Example 1 Low molecular weight polypropylene commercially available under the trade name of Viscol 660P has a melt viscosity at 160 ° C. of 73 cps, and has two maximum values in a chromatograph by GPC, and the maximum molecular values are 500 and 7500, The ratio of weight average molecular weight / number average molecular weight was 4.1. This was used as a release agent for comparison (6)
And

Comparative Example 2 A styrene-based resin was polymerized in the same manner as in Example 6 using the release agent 6, to obtain a resin composition (4) for comparative electrophotographic toner.

Comparative Example 3 Polypropylene (MI: 9, propylene homopolymer)
Through a tube without a built-in static mixer, heat deteriorating, melt viscosity at 160 ° C 250 cps, G
There are two maxima in the cutout graph on the PC, the maximum molecular weights being 600 and 10,000, and the weight average molecular weight /
The ratio of the number average molecular weight was 4.6. This is designated as Comparative Release Agent (7).

Comparative Example 4 An esterification reaction was carried out in the same manner as in Example 4 using the release agent 7, to obtain a comparative electrophotographic toner resin composition (5).

Use Example 1 Release agent (1) and thermoplastic resin binder (1)
Was used to produce an electrophotographic toner by the following method, and an electrophotographic developer was produced.

Toner production method Thermoplastic resin binder (1) 100 parts Release agent (1) 3 parts Carbon black MA-100 6 parts (Mitsubishi Kasei Kogyo Co., Ltd.) Eisen Spiro Black TRH 1 part (Hodogaya Chemical Industry Co., Ltd.) )) After blending the above compound with powder, use a Labopus mill
The mixture was kneaded at 140 ° C. × 30 rpm for 10 minutes, and the obtained kneaded material was finely pulverized with a jet mill PJM 100 (manufactured by Nippon Pneumatic). Using an airflow classifier MDS (manufactured by Nippon Pneumatic Co., Ltd.), fine powder of 5 μ or less was cut from the finely pulverized material. Aerosil R972 (manufactured by Nippon Aerosil Co., Ltd.) is added to 1,000 parts of the obtained powder.
Were uniformly mixed to obtain a toner.

Developer Preparation Method Electrophotographic developer 1 was obtained by mixing 1,000 parts of an electrophotographic carrier iron powder (F-100 manufactured by Nippon Iron Powder Co., Ltd.) with 25 parts of the above toner.

Use Example 2 An electrophotographic developer 2 was obtained in the same manner as in Use Example 1 except that the release agent (1) was changed to the release agent (2).

Use Examples 3 to 5 Electrophotographic developers (3) to (5) were prepared in the same manner as described above using the resin compositions (1) to (3) for electrophotographic toner. The mixing ratio of the toner was as follows.

Mixing ratio of toner 100 parts of resin composition for electrophotographic toner 6 parts of carbon black MA-100 (manufactured by Mitsubishi Kasei Kogyo Co., Ltd.) 1 part of Eizen Spiro Black TRH (manufactured by Hodogaya Chemical Industry Co., Ltd.) Comparative usage example 1, 2 Electrophotographic developers (6) and (7) were prepared in the same manner as described above using the resin compositions (4) and (5) for electrophotographic toner. The mixing ratio of the toner was as follows.

Compounding ratio of toner 100 parts of resin composition for electrophotographic toner 6 parts of carbon black MA-100 (manufactured by Mitsubishi Kasei Kogyo Co., Ltd.) 1 part of Eizen Spiro Black TRH (manufactured by Hodogaya Chemical Industry Co., Ltd.) Comparative usage example 3 heat An electrophotographic developer (8) was prepared in the same manner as described above using the plastic resin-based binder (1). The mixing ratio of the toner was as follows.

Mixing ratio of toner Thermoplastic resin binder 100 parts Carbon black MA-100 6 parts (Mitsubishi Kasei Kogyo Co., Ltd.) Eisen Spiro Black TRH 1 part (Hodogaya Chemical Industry Co., Ltd.) Filming to carrier 100r for 3 hours with developer in a tumbler shaker mixer
After stirring at pm, the amount of toner adhering to the carrier surface was observed with a microscope.

The binder containing the low-molecular-weight polypropylene which is the release agent of the present invention is excellent not only in the releasability but also in the fluidity of the toner as well as in the carrier as shown in the use examples (1) to (5). It was confirmed that the toner adhesion (filming to the carrier) was small.

[Effects of the Invention] When the release agent of the present invention and the binder of the present invention containing the release agent are blended into a toner, not only the release performance and hot offset resistance are excellent, but also the conventional low molecular weight polypropylene is used. It is possible to prevent a decrease in the fluidity of the toner, which is inevitable when the toner is used, and to prevent an increase in the amount of the filmed material adhered to the carrier, and its usefulness is extremely high.

Claims (4)

(57) [Claims] (1) a melt viscosity at 160 ° C. is not more than 1000 cps, a substantially maximum value is one in a gel permeation chromatography, and a ratio of a weight average molecular weight to a number average molecular weight is 2.9: 1.0-3.8: 1.0
Release agent for an electrophotographic toner comprising a low molecular weight polypropylene resin. 2. The release agent for an electrophotographic toner according to claim 1, wherein the low molecular weight polypropylene resin is a low molecular weight polypropylene resin having a propylene unit content of 75% by weight or more. 3. A thermoplastic resin binder and a thermoplastic resin binder.
Or a resin composition for an electrophotographic toner, comprising the release agent according to 2. 4. The resin composition for an electrophotographic toner according to claim 3, wherein the thermoplastic resin binder is a styrene resin, a polyester resin or a composite of both.