JPH0429249A - Electrophotographic toner composition - Google Patents

Abstract

PURPOSE:To obtain an improved toner composition having the improved resistance to the offset property and the improved electric chargeability by incorporating a binder resin which is obtained from the copolymerization of a specific monomer with the other vinyl monomer and is also crosslinked with the specific monomer. CONSTITUTION:The composition incorporates the binder resin for which the monomer (A) of 0.1-30 wt. parts, represented with formula I and the other vinyl monomer (B) of 99.9-70wt. parts are copolymerized and it is also crosslinked with the monomer (A). In formula I, R1 represents a hydrogen or a methyl group and R2 represents a 1-8C alkyl group. Hence the toner composition having an excellent high temp. offset property and the improved electrostatical chargea bility is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a toner composition for developing electrostatic images in electrophotography, electrostatic recording, electrostatic printing, and the like.

[Conventional technology]

Electrophotography generally uses a photoconductive substance to form an electrical latent image on a photoreceptor by various means, and then develops the latent image with toner to transfer it to a fixed object such as paper. This is a method in which a toner image is transferred onto a sheet and then fixed. the current,
The most common fixing method is a heat-pressing method using a heat roller. In the heat-pressing method using a hot roller, the surface of the toner is formed with a material that has good releasability, and the toner image on the fixing sheet is passed through the sheet while being in contact with the heated roller under pressure, thereby fixing the toner. This method performs fixing under heat and pressure, so it is quick and has extremely good thermal efficiency. Therefore, it has good fixing efficiency and is an effective fixing method for high-speed electrophotographic copying machines.

In the hot roller fixed fixing method, since the hot roller surface and the toner are in contact with each other under melting pressure, a portion of the toner adheres to the hot roller surface and is transferred, and this is transferred again to the next sheet to be fixed. This causes a so-called offset phenomenon. Therefore, one of the challenges of the fixed heat roller adhesion method is to prevent toner from adhering to the surface of the heat roller.

In order to improve the offset from a mechanical aspect, for example,
The roller surface is treated with a material such as fluorine-based resin or silicone rubber that has excellent mold releasability for toner, and the surface is then coated with a film of liquid such as silicone oil that has good mold releasability. It is. However, although this method is extremely effective in preventing high-temperature offset of toner, it has the problem of complicating the apparatus, such as a supply mechanism for the offset prevention liquid.

Therefore, it is desired to develop a toner that has particularly excellent high-temperature offset properties and a wide fixing temperature range.

Conventionally, toners used in hot roller constant fixing electrophotography use, for example, copolymers of styrene and acrylic vinyl monomers as binder resins, but these resins do not have the above-mentioned offset resistance. There was a problem with that.

This kind of offset phenomenon is described in Japanese Patent Publication No. 51-23354.
This tends to occur when a low molecular weight resin such as that described in the above publication is used. Therefore, as described in the same publication, it is thought that the offset phenomenon can be prevented by using a crosslinked resin, but as a result of the studies conducted by the present inventors, it has been found that simply using a crosslinked resin does not necessarily prevent the offset phenomenon. It was found that good results could not be obtained. In particular, when the degree of crosslinking is increased, the melting temperature becomes higher, which makes it necessary to raise the temperature of the hot roll, resulting in poor low-temperature offset properties, which poses many problems.

In addition to fixing properties, toner also has anti-blocking properties,
It is necessary to have excellent development properties, transferability, cleaning properties, in-machine contamination resistance, etc., but conventional toners have had one or more of the above-mentioned defects. That is, many toners that are easily melted at relatively low temperatures by heating are susceptible to blocking during storage or in a copying machine. Due to changes in the temperature and humidity of the environment, the triboelectric properties and fluidity become poor. Due to repeated development through continuous use, carrier particles and toner particles collide in the two-component development method, and toner particles due to friction between the plate and toner and their contact with the photoconductor surface in the -component (magnetic and non-magnetic) development method. Mutual deterioration of the carrier particles and the photoreceptor changes the density of the resulting image or increases the background density, reducing the quality of the object. Furthermore, if an attempt is made to increase the density of a photographed image by increasing the amount of toner adhering to the surface of a photoreceptor having a latent image, the background density usually increases, resulting in a so-called fog phenomenon.

Therefore, it is desired to provide a toner that does not have the above-mentioned problems, has excellent toner properties, and is suitable for the hot roller fixation method.

[Problems to be Solved by the Invention] An object of the present invention is to provide a toner that improves the drawbacks of the conventional toner and has excellent performance.

That is, an object of the present invention is to provide a toner composition that has good fixing properties, particularly good anti-offset properties, and is constantly worn by a heated roller. Another object of the present invention is to provide a toner composition that has good charging properties and stable charging properties during use, and is capable of obtaining clear images without capri, and is constantly worn by a heated roller.

Another object of the present invention is to provide a toner composition that has excellent fluidity, does not cause agglomeration, and has excellent impact resistance, and is constantly worn by a heated roller. Another object of the present invention is to provide a toner composition that can be constantly worn on a heated roller with less deposits on the surface of a toner holding member or photoreceptor. A further object of the present invention is to provide a toner composition that exhibits good and uniform magnetism when used as a magnetic developer and is constantly worn by a heated roller.

[Means for Solving the Problems 1] In order to achieve these problems, the present invention has discovered that it is effective to use a polymer condensed and crosslinked using a reactive amide as a binder resin for toner, and has developed the present invention based on the present invention. completed the invention.

That is, the present invention relates to the general formula (I) CH2=C-C-NH-CH2-0-R20 (■) (wherein, R1 represents hydrogen or a methyl group, and R2 represents C1
- Represents a C8 alkyl group) obtained by copolymerization of 0.1 to 30 parts by weight of a monomer (A) represented by and 99.9 to 70 parts by weight of another vinyl monomer (B), A toner composition for electrophotography is characterized in that it contains a binder resin cross-linked with a binder (A).

The toner composition of the present invention has excellent physical and chemical properties, and can achieve good fixed adhesion to the heat roller without applying an anti-offset liquid to the surface of the fixing roller, simplifying and lightweighting the fixing device. can, and furthermore,
Since it has stable and excellent developing characteristics, it is possible to significantly improve the reliability and stability of copying machines.

Specific examples of the monomer (A) of the present invention include methyl such as N-methoxymethyl acrylamide, N-ethoxymethyl acrylamide, N-propoxymethyl acrylamide, N-butoxymethyl acrylamide, N-hexaoxymethyl acrylamide, and N-octoxymethyl acrylamide. Alkoxyacrylamides, methylalkoxymethacrylamides such as N-methoxymethylmethacrylamide, N-ethoxymethylmethacrylamide, N-propoxymethylmethacrylamide, N-butoxymethylmethacrylamide, N-hexaoxymethylmethacrylamide, N-octoxymethacrylamide; Among them, Nn-butoxymethylacrylamide is preferred, but any monomer having a methylalkoxy group can be selected and used in order to adjust the hardness and elasticity of the binder resin.

The amount of monomer (A) in the binder resin is 0.1 to 30% by weight, preferably 0.5 to 20% by weight. If it is less than 0.1% by weight, the effect of improving high temperature offset resistance is small;
If it exceeds 30% by weight, fixing properties will deteriorate.

The binder resin of the present invention is a copolymer of Chizuma (A) and another vinyl monomer (B), and is crosslinked by Chizuma (A). That is, crosslinking is achieved by a condensation reaction of the methylalkoxy groups of the molecule (A). Crosslinking can be adjusted to a desired degree by changing the amount of mercury (A).

Here, other vinyl monomers (B) include, for example:
Methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, octyl acrylate, cyclohexyl acrylate, lauryl acrylate, stearyl acrylate, benzyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate, hydroxyethyl acrylate , hydroxybutyl acrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, and other acrylic acid esters: methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, octyl methacrylate, methacrylate Acid lauryl, stearyl methacrylate, cyclohexyl methacrylate, pencil methacrylate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, methacrylate dimethylaminoethyl acid,
Methacrylic acid esters such as diethylaminoethyl methacrylate: aromatic vinyl monomers such as vinyltoluene, a-methylstyrene, chlorstyrene, and styrene, dibutyl maleate, dioctyl maleate, dibutyl fumarate, dioctyl fumarate, etc. Unsaturated dibasic acid dialkyl esters: vinyl esters such as vinyl acetate and vinyl propionate, nitrogen-containing vinyl monomers such as acrylonitrile and methacrylonitrile, acrylamide, methacrylamide, N-N-dimethylacrylamide, N - Amide vinyl monomers such as methylol acrylamide and diacetone acrylamide, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and cinnamic acid; unsaturated dicarboxylic acids such as maleic acid, maleic anhydride, fumaric acid, and itaconic acid. Acids; unsaturated dicarboxylic acid monoesters such as monomethyl maleate, monoethyl maleate, monobutyl maleate, monooctyl maleate, monomethyl fumarate, monoethyl fumarate, monobutyl fumarate, monooctyl fumarate;
Sulfonic acids such as styrene sulfonic acid and acrylamide propane sulfonic acid Divinyl compounds such as divinylbenzene, (poly)ethylene glycol diacrylate, and (poly) ethylene glycol dimethacrylate: Conjugated diolefins such as butadiene, chlorobrene, neoprene, and isobutylene They are unsaturated monomers, and at least one of these monomers is used. Among these,
Particularly preferred are acrylic esters, methacrylic esters, styrene, fumaric acid dialkyl esters, acrylonitrile, methacrylic acid, cinnamic acid, and fumaric acid monoesters.

The production of a binder resin by copolymerization of acetic acid (A) and another vinyl monomer (B) is carried out, for example, by the following method.

That is, it is usually produced by a suspension polymerization method, a bulk polymerization method, or a solution polymerization method. Among these, solution polymerization is preferred.

In the case of solution polymerization, solvents include aromatic hydrocarbons such as benzene, toluene, ethylbenzene, ortho-xylene, metaxylene, baraxylene, and cumene; alcohols such as methanol, ethanol, propatool, butanol, hexanol, and octatool. These solvents may be used alone or in combination, but it is also possible to select other solvents to adjust the molecular weight.

Solution polymerization is usually carried out at a reaction temperature of 80 to 150°C, but may be carried out outside this range in order to control the molecular weight. As the polymerization initiator in solution polymerization, any initiator that can be used as a radical polymerization initiator can be used. For example, 2.2'-azobisisobutyronitrile, 2.2'-azobis(4 -methoxy-2,
4-dimethylvaleronitrile), 2,2'-azobis(-2,4-dimethylvaleronitrile), 22°-azobis(-2methylbutyronitrile), dimethyl-22
-azobisisobutyrate, l, 1゛-azobis(1-
cyclohexanecarbonitrile), 2-(carbamoylazo)-isobutyronitrile, 2.2°-azobis(2
, 4,4-trimethylpentane), 2-phenylazo-
2,4-dimethyl-4-methoxyvaleronitrile, 2.
Azo initiators such as 2'-azobis(2-methyl-propane), ketone peroxides such as methyl ethyl ketone peroxide, acetylacetone peroxide, and cyclohexanone peroxide O:1,1-bis(t
-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(butylperoxy)cyclohexane, 2-2-bis(t-butylperoxy)butane, and other peroxyketals; t-butylperoxy) Hydroperoxysite, cumene hydroperoxysite, 1
, 1,3.3-tetramethylbutylhydroperoxide; di-t-butyl peroxide, t-butylcumyl peroxide, di-cumyl peroxide, 2,5-dimethyl-2, 5-
Di(t-butylperoxy)hexane, a α bis(t
Dialkyl peroxides such as (butylperoxyisopropyl) benzene, isbutyryl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, 3,5.5-1-
Diacyl peroxides such as trimethylhexanoyl peroxide, benzoyl peroxide, m-toluoyl peroxide, di-isopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-n-propylene Peroxydicarbonates such as bilber oxydicarbonate, di-2-ethoxyethyl peroxycarbonate, di-methoxyisoprobilber oxydicarbonate, and di(3-methyl-3-methoxybutyl) peroxycarbonate; acetylcyclohexylsulfonyl Sulfonyl peroxides such as peroxide; t-butyl peroxy acetate, t-butyl peroxy isobutyrate, t-butyl peroxy neodecanoate, cumyl peroxy neodecanoate, t-butyl peroxy 2- Examples include peroxy esters such as ethylhexanoate, t-butylperoxylaurate, t-butylperoxybenzoate, t-butylperoxyisopropyl carbonate, and di-t-butylshiba-oxyisophthalate. , the type and amount thereof can be appropriately selected and used depending on the reaction temperature, monomer concentration, etc.

Crosslinking is usually carried out at a reaction temperature of 80 to 230°C, preferably 120°C.
The reaction is carried out at a temperature of 210° C. to 210° C., but it can be carried out outside this range in order to control the rate of the crosslinking reaction. In the crosslinking reaction, a condensation product is produced by a condensation reaction. This condensation product and the solvent used in the solution polymerization are generally removed by a reduced pressure method. The degree of decompression is generally 50mm
The range is from Hg to 3 mmHg, but depending on the type of condensation product and polymerization solvent, it can be carried out outside this range. It is also possible to carry out the crosslinking reaction and the solvent removal step separately.

Further, the degree of crosslinking is 0.1 to 85% by weight, preferably 0.5 to 85% by weight, as the value of insoluble content measured using ethyl acetate solvent.
It is in the range of 80% by weight. If the insoluble content is less than 0.1% by weight, there will be little effect on high-temperature offset properties, and if it is 85% by weight or more, low-temperature offset properties will deteriorate.

The binder resin used in the toner composition of the present invention may be the above-mentioned binder resin alone, or may be used in combination with other polymers.

When used in combination with another polymer, the other polymer is used in an amount of 1 part by weight or more, preferably 7 parts by weight or more, but less than 200 parts by weight, per 100 parts by weight of the binder resin.

Other polymers include, for example, styrene resin, styrene acrylic resin, polyvinyl chloride, polyolefin, polyester, polyvinyl butyral, polyurethane, polyamide, rosin, modified rosin, terpene resin, phenolic resin, epoxy resin, fumarate styrene resin, maleic resin, etc. Examples include acid ester styrene resin, styrene butadiene resin, paraffin wax, and polyolefin wax.

In order to produce the electrophotographic toner composition of the present invention, a powder obtained by pulverizing the binder resin by a conventional method, various coloring agents such as carbon black, and, if necessary, adjusting the triboelectric charging property are used. For example, charge control agents such as acid dyes and metal-containing azo dyes, auxiliary agents such as polyolefin wax, stearic acid derivatives, and silicone oil that help prevent offset, and magnetic oxidation and reduced iron powder in the case of magnetic toner. After mixing and kneading with a kneader etc.,
It can be crushed and classified to form a toner composition. The amount of binder resin in the toner composition is usually in the range of 35 to 95%.

〔Example〕

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 Production of binder resin N-n-butoxymethylacrylamide (hereinafter abbreviated as NBMA) in which R1 is hydrogen and R2 is an n-butyl group in maximum (I) was used as the binder resin (A), The following experiment was conducted.

Add 100g of Kijirole to a flask at 4°C,
After raising the temperature to 0°C, add 5 g of NBMAO, 770 g of styrene as other vinyl-based polymers (B), and 2 butyl acrylate.
A mixed solution of 30 g and 20 g (2% of monomers) of azobitbutylnitrile (hereinafter abbreviated as A-BN) as a catalyst was dropped into the flask over 4 hours, and further heated to 100°C.
Polymerization was carried out for 3 hours. Then 200℃, 100mmHg
The temperature and pressure were increased to below. This state was maintained for 1 hour to remove the condensation product in the system and the reaction solvent pheasant to obtain a binder resin. The state of crosslinking was confirmed by checking the amount insoluble in ethyl acetate.

How to measure the degree of crosslinking.

The gel fraction was measured by a method using a Soxhlet extractor under the following conditions.

Precisely weigh 10g of the obtained binder resin in a &86R thimble filter paper manufactured by Toyo Roshi Co., Ltd., and extract it with 100cc of ethyl acetate and a small amount of zeolite in a 250cc round-bottomed flask under heating under reflux for 16 hours to remove crosslinking. Separate the resin that was not removed, weigh the resin (gel) that remained in the thimble, and
Calculated.

The calculation was performed by accurately weighing the thimble filter paper and the binder resin that had been left for 48 hours in a constant temperature and humidity room with a humidity of 55% and a temperature of 20°C, and on the other hand, the thimble filter paper taken out after extraction with a Soxhlet extractor was weighed. After vacuum drying at 60°C for 8 hours to remove ethyl acetate, it was dried in a constant temperature and humidity room at 55% humidity and 20°C for 4 hours.
It was left to stand for 8 hours, and its weight was accurately weighed. Table 1 shows the content of this gel.
Shown below. The gel content was calculated using the following formula.

-c

Manufacture of toner composition: A toner composition was experimentally produced using the binder resin in the following manner.

100 parts by weight of the binder resin, 7 parts by weight of carbon black, 3 parts by weight of polyethylene wax, Subiron Black T
0.5 parts by weight of RH was mixed, melt-kneaded in a twin-screw extruder, pulverized in a jet pulverizer, and classified to a particle size of 8.
A toner of ~15 μm was produced to obtain Toner A. Table 1 shows the evaluation results of this toner.

Note that the evaluation was based on the following method.

Offset resistance was measured by changing the temperature of the hot roll and measuring the temperature at which offset occurred. The fixing property was determined by measuring the weight loss using a taper abrasion tester after fixing at 160°C. The charge amount was determined based on the practical charge amount at a humidity of 55% and a temperature of 20° C. and at a humidity of 95% and a temperature of 35° C. The charge amount was measured using a blow-off charge measuring device that mixed 4 g of the toner under the above conditions and 96 g of the iron powder carrier in a V-type powder mixer (capacity 250 cc) for 1 hour. Other image quality was visually judged.

Below, toner B-N was produced in exactly the same manner as toner A, except that the binder resin composition and polymerization conditions were changed as shown in Table 1, and the evaluation results are shown in Table 1 and Table 1. Shown in 2.

Example 2 Examples of combined use of the binder resin of the present invention and other polymers will be shown.

The binder resin used in Toner H (NBMA 30% by weight copolymer) and the non-crosslinked vinyl copolymer of Toner M used in Comparative Example 1 described below were mixed in a ratio of 8:2, and this mixture was mixed in the same manner as Toner A. A toner was obtained under the following conditions to obtain toner 0. The evaluation was conducted under the same conditions as Toner A, and the evaluation results are shown in Table 2. The following toners are ○ except that the binder mixing ratio was changed as shown in Table 2.
Toners P and Q were produced in exactly the same manner as in Example 1, and the evaluation results are shown in Table 3.

Comparative Example 1 As a comparison for the present invention, styrene and acrylic toners that are commonly used were evaluated.

Add 1000g of pheasant roll into a 4J2 flask and add 10
After raising the temperature to 0℃, 770g of styrene, 2 butyl acrylate
A mixed solution of 30 g of AlBN and 20 g of AlBN as a catalyst was dropped into the flask over 4 hours, and polymerization was further carried out at 100° C. for 3 hours. Next, temperature increase and pressure reduction was started, and the temperature was increased to 10 mm at 200°C.
The pressure was reduced to below Hg, and this state was maintained for 1 hour to remove the reaction solvent pheasant from the system to obtain a vinyl copolymer. This vinyl copolymer was made into a toner under the same conditions as Toner A to obtain Toner R. Evaluation was conducted under the same conditions as toner A. The evaluation results are shown in Table 2.

Comparative Example 2 As a comparison with the present invention, toners in which condensation and crosslinking reactions were suppressed from among the examples were evaluated.

Add 1000g of Kijirole to a 4β flask,
After raising the temperature to 0°C, 30 g of N BMA, 740 g of styrene
g, butyl acrylate 230g, AlBN as a catalyst
20 g of the mixed solution was dropped into the flask over 4 hours, and polymerization was further carried out at 100° C. for 3 hours. Then 10m at 70℃
The pressure was reduced to below mHg. This state was maintained for 1 hour to remove the reaction solvent quijirole from the system to obtain a vinyl copolymer. This vinyl copolymer was made into a toner under the same conditions as Toner A to obtain Toner S. Evaluation was conducted under the same conditions as Tona-A. The evaluation results are shown in Table 3.

Comparative Example 3 As a comparison with the present invention, a toner using a vinyl copolymer crosslinked using a commonly used crosslinking agent was evaluated.

Add 1000g of Kijirole to a 4β flask,
After raising the temperature to 0°C, add 10 g of divinylbenzene as a crosslinking agent, 770 g of styrene, 230 g of butyl acrylate, and A as a catalyst.
A mixed solution of 20 g of lBN was dropped into the flask over 4 hours,
Polymerization was further carried out at 100°C for 3 hours. Then, the temperature and pressure were increased to 10 mmHg or less at 200° C. and the pressure was reduced. This state was maintained for 1 hour to remove the reaction solvent pheasant from the system to obtain a vinyl copolymer. This vinyl copolymer is used as toner A.
A toner was obtained under the same conditions as described above to obtain Toner T. Evaluation was conducted under the same conditions as toner A.

The evaluation results are shown in Table 3.

Table [Effects of the Invention] The electrophotographic toner composition of the present invention exhibits excellent effects in high temperature offset resistance. It has also been found that the charging properties are improved, and the image density becomes even clearer. Regarding other toner properties such as anti-blocking property, developability, transferability, cleaning property, pulverizability, and in-machine contamination, toner compositions using the toner composition of the present invention are superior to those of conventional toners.

Patent applicant Mitsui Toatsu Chemical Co., Ltd. teenager Reason Man

Claims (2)

[Claims] (1) General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (In the formula, R1 represents hydrogen or a methyl group, and R2 represents C1
- C8 alkyl group) obtained by copolymerization of 0.1 to 30% by weight of a monomer (A) represented by and 99.9 to 70% by weight of another vinyl monomer (B), and An electrophotographic toner composition comprising a binder resin crosslinked with a monomer (A). (2) The electrophotographic toner composition according to claim 1, wherein the ethyl acetate insoluble content is in the range of 0.1 to 85% by weight.