JP2634308B2 - Resin composition for toner and toner - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a resin composition for toner used for developing an electrostatic image in electrophotography and the like, and a toner using the resin composition.

(Prior Art) In electrophotography and the like, a dry development method is often used as a method for developing an electrostatic image. In this dry development method, a triboelectrically-chargeable fine powder developer in which a carrier such as iron powder or glass beads is mixed with a fine powder called a toner in which a colorant such as carbon black is dispersed and contained in a resin is used.

Normally, toner charged by friction adheres to an electrostatic latent image on a photoreceptor by electrical attraction to form a toner image, and then this toner image is transferred onto paper to release the toner from the toner. The toner image is fixed by a hot-press fixing roller having a permanent visible image.

In such a hot-pressure fixing heating roller fixing method,
In order to achieve low power consumption and high copy speed, the toner used must have low-temperature fixability (toner sticks to the paper at a low temperature) and anti-offset properties (toner adheres to the heat and pressure fixing roller and is transferred to the paper. Performance) such as anti-blocking properties (no aggregation of toner particles).

As this type of toner, a toner in which a binder resin contains a solid alcohol at normal temperature has been proposed (for example, see JP-A-63-113558). Also, a toner in which a low molecular weight polypropylene is contained in a binder resin has been proposed (for example, see Japanese Patent Publication No. 52-3304).

(Problems to be Solved by the Invention) However, it is difficult for the conventional toner to satisfy all of the above three main performances in a well-balanced manner. For example, the former toner does not particularly have sufficient offset resistance. Further, the latter toner does not have sufficient low-temperature fixability. Further, in any of the toners, a problem may occur in the blocking resistance.

An object of the present invention is to solve the above problems, and an object of the present invention is to provide a resin composition for a toner and a toner which are excellent in all of low-temperature fixability, offset resistance and blocking resistance. .

(Means for Solving the Problems) The resin composition for a toner of the present invention has a weight average molecular weight of 4 to 4.
400,000, 100 parts by weight of a vinyl polymer having a glass transition point of 65 ° C. or higher, and an aliphatic alcohol 5 to 20 containing at least 90% by weight of an aliphatic alcohol having 15 to 90 carbon atoms and a melting point of 90 ° C. or lower.
It is characterized by containing, as main components, parts by weight and 2 to 7 parts by weight of a polyolefin wax having a penetration of 4 or less at 25 ° C.

Further, the toner of the present invention is characterized by containing the resin composition for a toner.

Examples of the vinyl polymer used in the present invention include a copolymer of a styrene monomer and a (meth) acrylate monomer, a homopolymer of a styrene monomer,
A homopolymer of a (meth) acrylate monomer is preferred.

Styrene-based monomers include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene,
α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-n-butylstyrene, p-tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n-dodecyl Examples include styrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, and 3,4-dichlorostyrene. Of these, styrene is preferred.

(Meth) acrylate monomers include
Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, (meth)
N-octyl acrylate, dodecyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth)
Lauryl acrylate, stearyl (meth) acrylate,
Examples thereof include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, and methyl α-chloroacrylate. Among these, methyl (meth) acrylate, n-butyl (meth) acrylate, propyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate are preferred.

Such vinyl monomers include (meth) acrylic acid, α-ethylacrylic acid, crotonic acid, isocrotonic acid, β-methylcrotonic acid, fumaric acid, maleic acid, and itaconic acid; mono (meth) acryloyl succinate Oxyethyl ester, mono (meth) acryloyloxypropyl succinate, mono (meth) acryloyloxyethyl glutarate, mono (meth) acryloyloxyethyl phthalate, mono (meth) acryloyloxypropyl phthalate; ) Acrylonitrile, (meth) acrylamide; and other vinyl monomers such as vinyl acetate, vinyl chloride, and ethylene.

The vinyl polymer used in the present invention is a solution polymerization,
It can be produced by a conventionally known polymerization method such as suspension polymerization, emulsion polymerization and bulk polymerization.

The vinyl polymer used in the present invention has a weight average molecular weight of 40,000 to 400,000 and a glass transition point of 65 ° C or higher. Here, the weight average molecular weight is a value measured by gel permeation chromatography (GPC). The glass transition point is a value measured by a differential scanning calorimeter (DSC). If the weight average molecular weight of the vinyl polymer is less than 40,000, the offset resistance becomes poor, and if the weight average molecular weight exceeds 400,000, the low-temperature fixability becomes poor. If the glass transition point is lower than 65 ° C., the blocking resistance of the toner will be poor.

Further, in the present invention, the melting point is 15 to 90 carbon atoms.
Use an aliphatic alcohol of 90 ° C or less. When an aliphatic alcohol having 14 or less carbon atoms is used, the compatibility with the vinyl polymer increases, the vinyl polymer is plasticized, and the blocking resistance of the toner deteriorates. On the other hand, if the number of carbon atoms is 91 or more or the melting point exceeds 90 ° C., the viscosity of the melting point becomes high, and the low-temperature fixability of the toner deteriorates.

Such aliphatic alcohols include pentadecanol, hexadecanol, heptadecanol, octadecanol, nonadecanol, eicosanol, docosanol, tetracosanol, hexacosanol, octacosanol, triancosanol, dotriancosanol, And NSP-9210 (alcohol type wax) manufactured by Nippon Seisen Co., Ltd.

Such aliphatic alcohols usually contain some aliphatic alcohols having 14 or less carbon atoms as impurities. When the aliphatic alcohol having 14 carbon atoms or less is contained in the aliphatic alcohol used in the present invention in an amount of more than 10% by weight, the compatibility with the vinyl polymer is increased and the vinyl polymer becomes plastic. And the blocking resistance of the toner deteriorates. Therefore, in the present invention, the carbon number is 15 to
At least 90 fatty alcohols with a melting point below 90 ° C
An aliphatic alcohol containing by weight is used.

Such an aliphatic alcohol is blended in an amount of 5 to 20 parts by weight based on 100 parts by weight of the vinyl polymer. If the amount of the aliphatic alcohol is less than 5 parts by weight, the low-temperature fixability of the toner hardly improves. Conversely, if it exceeds 20 parts by weight, sufficient charging cannot be obtained.

Further, in the present invention, a polyolefin wax having a penetration at 25 ° C. of 4 or less is used. Examples of the polyolefin wax include polypropylene wax, polyethylene wax, and polybutene-1 wax.
Here, the penetration is measured in accordance with JIS K 2235 (temperature 25
° C, total load 100g, time 5 seconds). If the penetration exceeds 4, the blocking resistance of the toner deteriorates.

Such a polyolefin wax is blended in an amount of 2 to 7 parts by weight based on 100 parts by weight of the vinyl polymer. If the blending amount of the polyolefin wax is less than 2 parts by weight, sufficient offset resistance cannot be obtained. Conversely, if the amount exceeds 7 parts by weight, the polyolefin wax is easily released from the toner, and the photosensitive drum is soiled.

In the present invention, in order to produce a resin composition for toner and a toner, an aliphatic alcohol and a polyolefin wax are blended with a vinyl polymer, and this is melted at an appropriate temperature using a roll mill, a kneader, an extruder or the like. A method of kneading, cooling and pulverizing, or after a solution polymerization of a vinyl monomer in the presence of an aliphatic alcohol, a polyolefin wax is charged into the system and stirred, and then the solvent is distilled off. A method of melt-kneading at an appropriate temperature using a roll mill, a kneader, an extruder, or the like, cooling, and finely pulverizing is suitably employed.

The resin composition for toner and the toner of the present invention include:
Within the range that can achieve the object of the present invention, resins such as polystyrene, polyvinyl acetate, polyvinyl chloride, polyamide resin, polyethylene, polypropylene, polyester resin, acrylic resin, and epoxy resin, and other toner additives are compounded. May be.

(Function) The resin composition for a toner and the toner of the present invention contain a specific vinyl polymer, a specific aliphatic alcohol, and a specific polyolefin wax at a specific ratio as main components. The basic performance required for the toner is obtained. The aliphatic alcohol is quickly melted by heating to lower the fusion temperature of the toner to the paper, and the polyolefin wax is quickly melted by heating to improve the releasability of the toner from the fixing roll. Further, the aliphatic alcohol prevents release of the polyolefin wax in the toner, and prevents the toner from adhering to the photosensitive drum and becoming dirty.

(Examples) Hereinafter, Examples and Comparative Examples of the present invention will be described.

Example 1 Production of Vinyl Polymer 900 g of toluene was put into a separable flask of No. 3 and 75 g of docosanol containing 0.5 wt% or less of an aliphatic alcohol having 14 or less carbon atoms was added, and the gas phase was replaced with nitrogen gas. The system was warmed to the boiling point of toluene. While stirring with toluene refluxing, styrene 400
g, methyl methacrylate 50 g, n-butyl acrylate 50 g
A solution in which 1 g of azobisisobutyronitrile was dissolved as a polymerization initiator was dropped over 2.5 hours to perform solution polymerization.

After completion of the dropwise addition, the mixture was aged for 10 hours while stirring at a temperature at which toluene was boiling. After that, while gradually raising the temperature of the system to 180 ° C, toluene was distilled off under reduced pressure,
A styrene-methyl methacrylate-n-butyl acrylate copolymer containing docosanol was produced.

The styrene-methyl methacrylate-n-butyl acrylate copolymer obtained under the same conditions except that the above-mentioned docosanol was not added was 80% by weight of a styrene component, 10% by weight of a methyl methacrylate component, and n-butyl acrylate. It comprises 10% by weight of a butyl component, has a weight average molecular weight of 70,000 and a glass transition point of 67 ° C.

Production of Resin Composition for Toner and Toner The styrene-methyl methacrylate-n-butyl acrylate copolymer containing docosanol described above was kneaded at 160 ° C. for 10 minutes in a kneader substituted with nitrogen gas, and then cooled. And crushed. 5 parts by weight of carbon black (MA-100: manufactured by Mitsubishi Kasei Corporation) and a penetration of 2
And 4 parts by weight of polypropylene wax were melt-kneaded, cooled, roughly pulverized, and further finely pulverized by a jet mill to prepare a toner powder having an average particle size of about 13 to 15 μm. 0.6 parts by weight of hydrophobic silica fine powder (R-972: manufactured by Nippon Aerosil Co., Ltd.) was added to this toner powder to produce a toner.

Performance Evaluation of Toner (1) Blocking Resistance 10 g of toner was collected in a 100 ml sample bottle, and this was taken at 50 ° C.
After standing in a thermostat for 16 hours, the blocking resistance was evaluated using a powder tester (manufactured by Hosokawa Micron).
○: No aggregation (cake formation) was observed in the toner particles.
, And the case where aggregation (cake formation) was observed was indicated by x. A toner which does not show aggregation (cake formation) under these conditions can be said to be an excellent toner.

(2) Low-temperature fixability 4 parts by weight of the toner are uniformly mixed with 96 parts by weight of an iron powder carrier having an average particle size of about 50 to 80 μm to prepare a developer. The developer and a commercially available electrophotographic copying machine (Fuji Xerox 3500) )
Was used to evaluate the low-temperature fixability.

A copy was obtained by changing the temperature of the fixing roll of the electrophotographic copying machine. The obtained copy was rubbed with an eraser for typewriter, and the lowest fixing roll temperature at which the density of the copy did not change was indicated as the minimum fixing temperature. A toner having this temperature of about 160 ° C. or less can be said to be an excellent toner.

(3) Offset resistance A copy was obtained by changing the temperature of the fixing roll of the electrophotographic copying machine. In this case, a blank sheet was supplied after obtaining the copy, and the contamination of the blank sheet with the toner was visually determined. The lowest temperature at which toner contamination occurs on white paper is indicated as the offset occurrence temperature. This test takes into account the heat resistance of the fixing roll.
Censored at 200 ° C. A toner having this temperature of about 200 ° C. or more can be said to be an excellent toner.

(4) Dirt on Photosensitive Drum After 2000 copies were continuously made, dirt on the photosensitive drum of the electrophotographic copying machine (which causes image fogging and a decrease in image density) was visually determined. The case where no contamination was observed on the photosensitive drum was indicated by ○, and the case where contamination was observed was indicated by ×. The charge state of the toner particles was stable, and the obtained image was clear without any fog. Table 1 summarizes the above results.

Example 2 As a vinyl polymer, styrene-methacrylic acid comprising 70% by weight of a styrene component, 15% by weight of a methyl methacrylate component, and 15% by weight of an n-butyl acrylate component, having a weight average molecular weight of 200,000 and a glass transition point of 68 ° C. Acid methyl-acrylic acid n
-Butyl copolymer was used.

A kneader in which 100 parts by weight of the above vinyl copolymer and 10 parts by weight of hexadecanol containing 0.5% by weight or less of an aliphatic alcohol having 14 or less carbon atoms were replaced with nitrogen gas.
After kneading at 160 ° C. for 10 minutes, the mixture was cooled and pulverized.
5 parts by weight of carbon black (MA-100: manufactured by Mitsubishi Kasei Co., Ltd.) and 4 parts by weight of a polypropylene wax having a penetration of 2 were melt-kneaded with 100 parts by weight of the pulverized material, cooled, coarsely pulverized, and further finely milled with a jet mill. This was pulverized to prepare a toner powder having an average particle size of about 13 to 15 μm. 0.6 parts by weight of hydrophobic silica fine powder (R-972: manufactured by Nippon Aerosil Co., Ltd.) was added to this toner powder to produce a toner.

The performance of this toner was evaluated in the same manner as in Example 1. The results are summarized in Table 1.

Example 3 As a vinyl polymer, 100 parts by weight of polystyrene having a weight average molecular weight of 40,000 and a glass transition point of 90 ° C. was used. Also,
Dotrianecontanol 2 containing 0.5% by weight or less of an aliphatic alcohol having 14 or less carbon atoms as an aliphatic alcohol
0 parts by weight were used. Further, 6 parts by weight of polyethylene wax having a penetration of 2 was used as the polyolefin wax. Other than that, it carried out similarly to Example 2. The results are summarized in Table 1.

Comparative Example 1 Except that no polypropylene wax was used,
Performed in the same manner as in Example 2. The results are summarized in Table 1.

Comparative Example 2 Except not using dotriancontanol at all,
Performed in the same manner as in Example 3. The results are summarized in Table 1.

Comparative Example 3 As a vinyl polymer, a styrene-methyl methacrylate-n-butyl acrylate copolymer having a weight average molecular weight of 500,000 and a glass transition point of 80 ° C was used. Otherwise, Example 2
The same was done. The results are summarized in Table 1.

Comparative Example 4 As a vinyl polymer, a styrene-methyl methacrylate-n-butyl acrylate copolymer having a weight average molecular weight of 10,000 and a glass transition point of 55 ° C. was used. Otherwise, Example 2
The same was done. The results are summarized in Table 1.

Comparative Example 5 As an aliphatic alcohol, docosanol containing 15% by weight of an aliphatic alcohol having 14 or less carbon atoms was used. Other than that, it carried out similarly to Example 1. The results are summarized in Table 1.

Comparative Example 6 As the aliphatic alcohol, an aliphatic alcohol having about 100 carbon atoms containing 0.5% by weight or less of an aliphatic alcohol having 14 or less carbon atoms was used. Also, 4 parts by weight of polypropylene wax was changed to 20 parts by weight. Other than that, it carried out similarly to Example 1. The results are summarized in Table 1.

(Effects of the Invention) As described above, the resin composition for a toner and the toner of the present invention comprise, as main components, 100 parts by weight of a vinyl polymer having a weight average molecular weight of 40,000 to 400,000 and a glass transition point of 65 ° C or more; Number 1
5 to 90, at least 9
5 to 20 parts by weight of an aliphatic alcohol containing 0% by weight;
And 2 to 7 parts by weight of a polyolefin wax having a penetration degree of 4 ° C. or less. Dirt is prevented. Also,
The charged state of the toner particles is stable, and the obtained image is clear without any fog.

Therefore, the resin composition for toner and the toner of the present invention can be suitably used in an electrophotographic copying machine of a hot and pressure roller fixing system ranging from low speed to high speed.

Claims (2)

(57) [Claims] (1) a weight average molecular weight of 40,000 to 400,000 and a glass transition point of 65
100 parts by weight of a vinyl polymer having a temperature of at least
At least 90% by weight of aliphatic alcohol with melting point below 90 ° C
A resin composition for a toner comprising, as main components, 5 to 20 parts by weight of an aliphatic alcohol to be contained and 2 to 7 parts by weight of a polyolefin wax having a penetration of 4 or less at 25 ° C. 2. A toner containing the resin composition for toner according to claim 1.