JPH03260659A - Releasing agent and composition for electrophotographic toner - Google Patents

Abstract

PURPOSE:To enhance dispersibility of a releasing agent in a toner, offset resistance and electric charge stability of the toner by using a specified ethylene- propylene polymer as the releasing agent. CONSTITUTION:The resin to be used as the releasing agent is the block copolymer of ethylene and propylene, and it is preferred that a ratio of light absorbance of this copolymer at 998 cm<-1> to that at 974 cm<-1> (D998/D974) is >=0.75, the content of ethylene in the copolymer is <=25 wt.%, and it is prepared by heat degradation of this copolymer or by oxidation decomposition of this copolymer, or by its modification by using an ethylenically unsaturated monomer.

Description

[Detailed description of the invention] [Industrial application fields] The present invention relates to a release agent and composition for electrophotographic toner.

More specifically, the present invention relates to a release agent and composition for electrophotographic toners that are suitable for heat-fixing type copying machines or printers and have excellent charging characteristics and fixing characteristics.

[Prior Art] Toner of the heat fixing method is fixed on a support by a heat roller. In this case, it is desired that the lower limit temperature of fixing is low. On the other hand, when the roll temperature increases, a phenomenon occurs in which toner sticks to the roll. It is desirable that the temperature at which this hot offset occurs is high. Generally, as the molecular weight of the binder increases, the hot offset temperature increases, but at the same time, the minimum fixing temperature also increases. Conversely, when the molecular weight decreases, both the hot offset temperature and the lower limit fixing temperature decrease.

As a method for meeting this contradictory performance requirement, an electrophotographic j-ner is known in which a release agent such as low molecular weight polypropylene is added to increase the hot offset temperature (for example, Japanese Patent Publication No. 3304/1982).

[Problems to be Solved by the Invention] However, when a polyolefin resin such as low molecular weight polypropylene is added, the polyolefin resin is insufficiently dispersed during toner production, resulting in a lack of toner charging stability and, when used for a long period of time, an image becomes thinner. Problems may occur.

[Means for Solving the Problems] The present inventor has intensively studied a release agent and composition for electrophotographic toners that improve the dispersibility of the release agent in the toner, have excellent charging stability, and have a high hot offset temperature. As a result, we have arrived at the present invention. That is, the present invention provides a release agent for an electrophotographic toner, which is made of an ethylene-propylene resin having a melt viscosity of 1000 cps or less at 160°C, and has a block structure of ethylene and propylene, and the release agent and the release agent. This is a composition for electrophotography 1 to 1 made of a thermoplastic resin.

The ethylene-propylene resin according to the present invention is ethylene-propylene resin.
Copolymers of other olefins besides propylene can also be used. Other orenes include butene, octene, and the like.

The ethylene-propylene resin according to the present invention has a block structure of ethylene and propylene. When ethylene and propylene have a random structure, the mechanical strength of the ethylene-propylene resin is poor, so when used continuously for a long period of time when used as an electrophotographic toner, the toner may deteriorate and lack charging stability.

The composition of the ethylene-propylene resin preferably has an ethylene content of 25% by weight or less. 25% by weight
Above this temperature, the mold release effect decreases and a sufficient offset temperature cannot be obtained.

The content of other resins is usually 10% by weight or less, preferably 5% by weight or less. If it exceeds 10% by weight, the release effect will be insufficient when used as a toner.

160°C of ethylene-propylene resin according to the present invention
The melt viscosity is 1000 cps or less, preferably 5
00 cps or less. If the melt viscosity at 160° C. exceeds 1000 cps, the hot offset effect will be poor when used in electrophotographic toners. Ethylene-
The melt viscosity of the propylene resin at 160°C is measured using a Brookfield rotational viscometer. Conditions other than the measurement temperature are in accordance with JIS-1557-1970. An oil bath with a temperature regulator is used to adjust the temperature of the measurement sample.

998 cm of ethylene-propylene resin according to the present invention
The ratio D998/D9° between the absorbance at "-' (Dqsa) and the absorbance at 974 cm-1 (D9□, ) is 0.75 or more, preferably 0.85 or more. Anything less than 0.75 is used as a toner. When used, sufficient fluidity was not obtained and 1 to
The toner may not be able to be supplied to the developing machine. Absorbance is measured with an infrared spectrophotometer.

The method for producing the ethylene-propylene resin according to the present invention is not particularly limited, but examples include 1) thermal degradation of a high molecular weight ethylene-propylene copolymer, and 2) oxidation of the ethylene-propylene resin. Examples include a method using an ethylene-propylene resin obtained by decomposition and having an acid value of 50 or less; and 3) a method of modifying the ethylene-propylene resin with an ethylenically unsaturated monomer.

When producing by thermal degradation of a high molecular weight ethylene-propylene copolymer in 1), the raw material high molecular weight ethylene-propylene copolymer has a melt index of usually 0.1 to 100, preferably 1 to 50. things are used. As a high molecular weight ethylene-propylene copolymer, J
A high molecular weight ethylene-propylene copolymer commercially available as 609H (manufactured by Ube Industries) can also be used. Thermal degradation converts high molecular weight ethylene-propylene copolymer into
300~ using a tubular reactor etc. that applies heat evenly
This can be carried out by passing at 450°C for 0.5 to 10 hours. The melt viscosity of the heat-degraded product can be adjusted by adjusting the heat-degradation temperature and heat-degradation time. If it is less than 300°C, it takes time to lower the melt viscosity, and if it exceeds 450°C, the melt viscosity lowers in a short time and becomes difficult to control.

In the case of oxidative decomposition in 2), a) high molecular weight ethylene-propylene copolymer or ethylene-propylene resin obtained by thermal degradation of 1) above is treated with oxygen or an oxygen-containing gas (
b) oxidation with ozone-containing oxygen or ozone-containing gas (air); b) oxidative decomposition of a high molecular weight ethylene-propylene copolymer and further thermal degradation thereof. The acid value of the oxide is usually 30 or less, preferably 10 or less. If the acid value is 30 or more, the mold release effect will be insufficient.

In the case of modification with an ethylenically unsaturated monomer (3), the ethylenically unsaturated monomer may be a styrene monomer (α-methylstyrene, P-methylstyrene, etc.) or a (meth)acrylic acid ester monomer. body [alkyl (meth)acrylate [
Those in which the alkyl group has 1 to 18 carbon atoms, such as methyl (
meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, and stearyl (meth)acrylate], hydroxyl group-containing (meth)acrylate-1-[hydroxyl ethyl (meth)acrylate, etc.], amino group-containing (meth)acrylates [dimethylaminoethyl (meth)acrylate, diethylamine ethyl (meth)acrylate, etc.], vinyl esters (vinyl #acid, etc.), vinyl ethers (vinyl ethyl ether, etc.), Ethylenically unsaturated group-containing aliphatic hydrocarbons (α-olefin, butadiene, etc.), nitrile group-containing vinyl compounds [(meth)acrylonitrile, etc., nitrogen-containing vinyl compounds (N-vinylpyrrolidone, etc.), unsaturated carboxylic acids or their Anhydrides [(meth)acrylic acid, maleic anhydride, itaconic anhydride, etc.], silicon-containing monomers (Trie 1 hexyvinylsilane, etc.), fluorine-containing monomers (perfluorohexaethyl methacrylate-1, etc.) etc. can be mentioned.

Among these, styrenic monomers, unsaturated carboxylic acid anhydrides, and silicon-containing monomers are preferred. The amount of ethylenically unsaturated monomer used for modification is usually 0.5% or more based on the weight of the mold release agent. Examples of the modification method include a method in which the ethylene-propylene resin obtained by thermal degradation in 1) is treated with a peroxide and an ethylenically unsaturated monomer is added (grafting, etc.). can.

The composition of the present invention comprises a mold release agent made of the above-mentioned ethylene-propylene resin and a thermoplastic resin. Thermoplastic resins include styrene resins, styrene-(meth)acrylate copolymers, polyester resins,
Epoxy resin or the like can be used.

The composition ratio of the mold release agent and the thermoplastic resin in the composition of the present invention can be arbitrarily selected.

The release agent and composition for electrophotographic toner of the present invention can contain the thermoplastic resin, colorant, and various additives, etc., if necessary, to form an electrophotographic toner.

Coloring agents include carbon, iron black, and benzidine yellow.
Examples include quinacudrine, rhodamine B, and phthalocyanine. As the magnetic powder, powders of ferromagnetic metals such as iron, Kohar 1 and nickel, or magnetite, hematite, ferrite, etc. may be used.

Furthermore, various additives include charge control agents such as guccicine, quaternary ammonium salts, etc.

The release agent and composition of the present invention may be added during toner production, or the release agent may be added in the form of a premixed mixture with the thermoplastic resin.

The production of electrophotographic toner is as follows: 1) After dry blending the toner components, the toner components are melt-kneaded, then coarsely pulverized, and finally pulverized using a jet pulverizer, and further classified to form a fine powder with a particle size of usually 2 to 20μ. 2) It can also be obtained by suspension polymerization of monomers constituting the thermoplastic resin in the presence of the other toner components to obtain a fine powder with a particle size of usually 2 to 20 μm, but in particular The manufacturing method is not limited to these.

The electrophotographic toner is mixed with carrier particles such as iron powder, glass beads, nickel powder, Ferrite 1, etc., as required, and used as a developer for an electrical latent image. Hydrophobic colloidal silica is also used to improve powder fluidity! Powders can also be used.

The electrophotographic toner is heated by a heat-fixing heat roll section of a copying machine, such as a heat-fixing type copying machine or a printer, so that it is fixed on a support (paper, polyester film, etc.) and used as a recording material.

[Example] The present invention will be further explained with reference to Examples below, but the present invention is not limited thereto.

In the examples, all parts represent parts by weight.

Example 1 Ethylene-propylene block copolymer manufactured by Ube Industries (ethylene content: 6% by weight) J609H 1000 parts was added to 35
The mixture was thermally formed by passing through a tubular reactor equipped with a static mixer heated to 0°C for a residence time of 1 hour to obtain an ethylene-propylene resin having a melt viscosity of 100 cps at 160°C and a D998/D9□4 ratio of 0.90. This is referred to as the mold release agent (1) of the present invention.

Example 2 Ethylene-propylene resin 100 obtained in Example 1
0 part was heated to 160°C in a reactor to form 2 parts of maleic anhydride.
0 parts and 5 parts of di-t-butyl peroxide were added and reacted for 3 hours, and the melt viscosity at 160°C was 140 cps.
An ethylene-propylene resin was obtained. This is referred to as the mold release agent (2) of the present invention.

Example 3 Ethylene-propylene resin 100 obtained in Example 1
0 part was heated to 250°C in an autoclave and air oxidized to obtain an ethylene-propylene resin having a melt viscosity of 80 cps at 160°C and an acid value of 2.

This is referred to as the mold release agent (3) of the present invention.

Comparative Example 1 The ethylene-propylene block copolymer of Example 1 was thermally degraded by the same method except that it was made into a high molecular weight polypropylene homopolymer, and the melt viscosity at 160°C was 2.
00cps, Dgga/D974 ratio is 0.65
A polypropylene resin was obtained. Compare this with mold release agent (1
).

Comparative Example 2 Thermal degradation was carried out in the same manner as in Example 1 except that the residence time was changed to 30 minutes, and the melt viscosity at 160°C was 1.
An ethylene-propylene resin of 500 cps was obtained. This is referred to as a comparative mold release agent (2).

Production Example 1 660 parts of styrene, 340 parts of butyl acrylate, solvent,
A thermoplastic resin was obtained by carrying out thermal polymerization at 130 to 180°C without using a polymerization initiator. The molecular weight of this resin was a number average molecular weight of 11,000 and a weight average molecular weight ff of 170,000. The molecular weight was measured by GPC method. Thermoplastic molecular weight measurement by GPC method was carried out under the following conditions.

Equipment: Toyo Sodagu HLC802A column:
TSK gel GMH62 measurement temperature: 40°
C Sample solution: 0゜5wt% THF solution solution injection amount =
200 μm Detection device: Refractive index detector Example 4 Using the release agent of Example 1 and the thermoplastic of Production Example 1, an electrophotographic toner was produced by the following method. Furthermore, an electrophotographic developer was produced.

1-ner preparation method Thermoplastic resin 87 parts Mold release agent of Example 1 4 parts Carbon black
8 parts (MA-100 manufactured by Mitsubishi Chemical Industries, Ltd.) Charge control agent 1 part (manufactured by Hodogaya Chemical Industries, Ltd.)
(Spiron Black TRH manufactured by Co., Ltd.) The above mixture was powder blended and then mixed with a twin screw extruder to
℃, kneaded at 200 rpm, and mixed the mixture in a jet mill PJ.
It was finely ground using M100 (manufactured by Nippon Pneumatic Co., Ltd.).

Fine powder of 2 μm or less was cut from the finely ground material using a powder air classifier MSD (manufactured by Nippon Pneumatic Co., Ltd.). Add 3 parts of Aerosil R972 (Japan Aerosil) to 1000 parts of the obtained powder.
Parts were uniformly mixed to obtain 1 to 3 parts.

Method for Preparing Developer 25 parts of the above toner was mixed with 1000 parts of carrier iron powder for electrophotography (F-100 manufactured by Nippon Tetsuko Co., Ltd.) to obtain a developer for electrophotography.

Example 5.6 An electrophotographic developer was obtained in the same manner except that the mold release agent of Example 1 was replaced with the mold release agent of Example 2.3.

Comparative Example 3.4 A comparative electrophotographic developer was obtained in the same manner except that the releasing agent of Example 1 was replaced with the releasing agent of Comparative Example 1.2.

Table 1 shows the evaluation results for each developer.

Table-1 Evaluation of developer Note) Dispersibility Optical microscope to measure release agent particle size in toner observed and evaluated by E　Average particle diameter less than 3μ G Average particle diameter 3μ or more and less than 5μ P Average particle diameter 5μ or more Hot offset resistance Using a commercially available heat-fixing copier, P1- where hot offset occurs Evaluation was made based on the temperature of the roll.

Good: 220°C or higher Poor: Below 220°C Charge stability Toner charge amount Q when 500 copies were made □ Toner charge amount Q2 when 10,000 copies were made was measured using a blow-off charge amount measuring device.

E 11- Qt / Q21≦0.1a O,1
<11- Q□/Q21≦0.3P O,3<lx-
Q1/Q21 It was confirmed that the electrophotographic lender containing the mold release agent of the present invention not only has excellent dispersibility of the mold release agent and hot offset resistance, but also excellent charging stability.

[Effect of the invention]

Claims (1)

[Scope of Claims] 1. A mold release agent for electrophotographic toner, comprising an ethylene-propylene resin having a melt viscosity of 1000 cps or less at 160° C., characterized in that the release agent has a block structure of ethylene and propylene. 2. 998cm of ethylene-propylene resin ^-^1
The ratio of the absorbance at (D_9_9_8) and the absorbance at 974 cm^-^1 (D_9_7_4) (D_9_9_8/D_9
_7_4) is 0.75 or more, the release agent for electrophotographic toner according to claim 1. 3. The release agent for electrophotographic toner according to claim 1 or 2, wherein the ethylene content is 25% or less based on the weight of the ethylene-propylene resin. 4. Ethylene-propylene resin is high molecular weight ethylene-
Claims 1 to 1 obtained by thermal degradation of a propylene copolymer.
3. The release agent for electrophotographic toner according to any one of 3. 5. The mold release agent for electrophotographic toner according to any one of claims 1 to 4, wherein the ethylene-propylene resin is obtained by oxidative decomposition and has an acid value of 30 or less. 6. The release agent for electrophotographic toner according to any one of claims 1 to 4, wherein the ethylene-propylene resin is modified with an ethylenically unsaturated monomer. 7. An electrophotographic toner composition comprising the release agent according to any one of claims 1 to 6 and a thermoplastic resin.