JPH07181717A - Electrophotographic resin composition and method for producing the same - Google Patents

Abstract

(57) [Summary] [Structure] A core layer made of an acrylic acid ester copolymer and / or a methacrylic acid ester copolymer having a glass transition temperature of 0 ° C. or lower is glass-transposed in a polystyrene or styrene-based copolymer resin. A resin composition for electrophotography, comprising a resin particle coated with a crosslinked vinyl polymer having a temperature of 50 ° C. or higher, and a method for producing the same. [Effect] It is possible to increase the resistance to the impact of the toner from the charge imparting member such as the carrier in the developing machine. In addition, a binder resin having a low molecular weight, which cannot be used conventionally, can be used as a developer. Further, the present invention provides a toner which can be fixed at a low temperature and has excellent impact resistance and stability over time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polystyrene or styrene copolymer resin composition used as a binder resin for toner used in electrophotography, electrostatic recording and the like, and a method for producing the same.

[0002]

BACKGROUND OF THE INVENTION Electrophotographic recording has been described in U.S. Pat. Nos. 2,297,691 and 2,357,809, in which the photosemiconductor layer is uniformly charged and then charged. Exposing the layer to dissipate the charge on the exposed areas to form an electrostatic latent image,
Further, a colored fine powder having a charge called toner is attached to the electrostatic latent image to form a visible image (developing step), and the obtained visible image is transferred to a transfer material such as paper (transfer step). , Heating, pressure or other suitable fixing method to permanently fix (fixing step).
Further, after the toner is transferred, a cleaning process for removing the toner remaining on the optical semiconductor is provided.

As described above, the toner must have the functions required not only in the developing process but also in the transferring process, the fixing process, the cleaning process and the like.

Typical methods for fixing the toner are a heat fixing method in which the toner is heated and melted and fixed on paper, and a pressure fixing method in which the toner is plastically deformed by pressure and fixed on the paper, but the apparatus is simple. The heat roll fixing method using a heat roll as the heating medium of the toner is most often used from the standpoints of the property and the quality of the image after fixing.

In the heat fixing method, the toner must be melted at a temperature as low as possible and fixed to a medium such as paper.
In recent years, especially from the viewpoint of energy saving, there is a high demand for low-temperature fixability of toner.

As a method for imparting low-temperature fixability to the toner, the molecular weight distribution of styrene copolymers, polyester resins, etc. used as a binder resin can be widened as shown in Japanese Patent Publication No. 55-6895. As shown in Japanese Examined Patent Publication No. 63-32182, it has been proposed that the molecular weight distribution has a double-peaked structure and the molecular weight distribution is shifted to the low molecular weight side to improve the thermal response. In addition, as a similar method, Japanese Patent Publication No.
The method of mixing a cross-linked polymer and a low molecular weight polymer, which is proposed in the above publication, is also often used.

However, in these methods, since a large amount of low molecular weight resin needs to be contained in the binder resin of the toner in order to secure the low temperature fixing property, the toner is extremely easily pulverized. That is, the toner for two-component developer used by mixing with the carrier is destroyed by the impact force received from the carrier in the developing machine to increase fine powder, which causes fog on the ground and adheres to the carrier surface to charge the toner. It may take away the ability to grant. On the other hand, even in the one-component developing method that does not use a carrier, the stress applied between the charging blade and the developing roll may stick to the charging blade or the developing roll, which may impair stable image reproduction.

As described above, it is extremely difficult to achieve both excellent low-temperature fixability and stable image reproducibility, and the present situation is that the level is not sufficiently satisfactory.

[0009]

Means for Solving the Problems As a result of intensive studies for achieving the above object, the present inventors have found that a polystyrene or styrene copolymer resin used for a toner having excellent stability over time and a low fixing temperature is used. Succeeded in providing stable and inexpensive high-quality copied images with proper image density and no background fog by using the toner that is completed and uses the polystyrene or styrene copolymer resin as a binder resin. did.

That is, according to the present invention, a core layer made of an acrylic acid ester copolymer and / or a methacrylic acid ester copolymer having a glass transition temperature of 0 ° C. or less is added to a glass transition temperature in polystyrene or a styrene copolymer resin. Relates to a resin composition for electrophotography, which comprises resin particles coated with a crosslinked vinyl polymer at 50 ° C. or higher.

Further, according to the present invention, a core layer made of an acrylic ester copolymer and / or a methacrylic ester copolymer having a glass transition temperature of 0 ° C. or lower has a glass transition temperature of
The present invention relates to a method for producing a resin composition for electrophotography, which comprises subjecting a polystyrene or styrene copolymer resin to polycondensation in the presence of resin particles coated with a crosslinked vinyl polymer at 50 ° C. or higher.

In the present invention, the resin particles dispersed in the polystyrene or styrene-based copolymer resin is an acrylic acid ester copolymer having a glass transition temperature of 0 ° C. or lower and / or
Alternatively, it can be obtained by emulsion polymerization of a methacrylic acid ester copolymer in advance and then seed emulsion polymerization in which a crosslinked vinyl polymer having a glass transition temperature of 50 ° C. or higher is coated.

Further, in order to improve the stability of emulsion polymerization when synthesizing the above resin particles, an acrylic acid ester copolymer and / or a methacrylic acid ester copolymer having a glass transition temperature of 0 ° C. or less, which is a rubber-like layer, is used. Prior to the polymerization of the polymer, an aromatic vinyl copolymer such as styrene, vinyltoluene, α-methylstyrene, monochlorostyrene, 3,4-dichlorostyrene, bromostyrene may be preliminarily polymerized to serve as the core of the rubber particles.

When the nuclei are polymerized, alkyl acrylates such as ethyl acrylate and butyl acrylate, alkyl methacrylates such as methyl methacrylate and butyl methacrylate, vinyl cyanide and cyanide such as acrylonitrile and methacrylonitrile. Non-aromatic monomers such as vinylidene chloride may be copolymerized. However, when the amount is large, the rubber-like portion and the core portion are mixed, and the rubber elasticity of the entire particle is impaired. Therefore, the content is 50% by weight or less, preferably 20% by weight, in the total monomers of the core portion. Used below. Further, the core portion may be crosslinked with a crosslinkable polymer. The amount of crosslinkable polymer used in the core is usually
It is 30% by weight or less, preferably 15% by weight or less of the core portion. Such crosslinkable polymers include aromatic vinyl monomers such as divinylbenzene, ethylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, hexanediol di (meth) acrylate,
Oligoethylene glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate and other alkane polyols Poly (meth) acrylate etc. Two or more polymerizable ethylenically unsaturated bonds in the molecule. A monomer having a can be used.

As the monomer having an ultimate glass transition temperature of 0 ° C. or lower, which is used for obtaining an acrylic acid ester copolymer or a methacrylic acid ester copolymer having a glass transition temperature of 0 ° C. or lower, which is a rubber-like layer, an acrylic resin can be used. Alkyl acrylates such as ethyl acidate, propyl acrylate, butyl acrylate, cyclohexyl acrylate and 2-ethylhexyl acrylate, octyl methacrylate, dodecyl methacrylate, alkyl methacrylates such as lauryl methacrylate and the like can be used. When polymerizing this rubbery layer, other vinyl-based monomers may be copolymerized with the above-mentioned alkyl acrylate and alkyl methacrylate. Examples of such monomers include styrene, vinyltoluene, α-methylstyrene, monochlorostyrene, 3,4-dichlorostyrene, aromatic vinyl copolymers such as bromostyrene, methyl methacrylate, and butyl methacrylate. However, the content of such a monomer is limited so that the glass transition temperature of the copolymerized polymer is 0 ° C. or lower.
Also, the rubber layer may be crosslinked with a crosslinkable monomer. As the crosslinkable monomer, aromatic vinyl monomer such as divinylbenzene, ethylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, hexanediol di (meth) acrylate, oligoethylene glycol di (meth) acrylate Alkane polyols such as acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, etc. Poly (meth) acrylate etc. Uses monomers with two or more polymerizable ethylenically unsaturated bonds in the molecule. can do. The amount of the crosslinkable monomer used is usually 0.01 to 5% by weight, and preferably 0.1 to 2% by weight, based on all the monomers forming the rubbery layer.

Further, the cross-linked vinyl polymer having a glass transition temperature of 50 ° C. or more for covering the rubber layer is styrene,
The same crosslinkable monomer as the compound used for the synthesis of the non-crosslinkable aromatic vinyl copolymer such as vinyltoluene, α-methylstyrene, monochlorostyrene, 3,4-dichlorostyrene and bromostyrene and the rubbery layer such as divinylbenzene. Polymerization is performed in combination with a monomer. The amount of crosslinkable polymer is usually the coating layer
It is 30% by weight or less, and preferably 5 to 15% by weight. When the amount of the crosslinkable polymer is small, the coating layer melts during the polymerization of the polystyrene or styrene-based copolymer and the rubber component having a low glass transition temperature is exposed in the polystyrene or styrene-based copolymer, so when used in the toner, Care must be taken because the storage stability of the toner may deteriorate. When the coating layer is polymerized, alkyl acrylates such as ethyl acrylate and butyl acrylate, alkyl methacrylates such as methyl methacrylate and butyl methacrylate, vinyl cyanide and vinylidene cyanide such as acrylonitrile and methacrylonitrile. Although a non-aromatic monomer such as the above may be copolymerized, if the amount is large, the rubber-like portion and the coating layer portion are mixed, the coating effect by the coating layer cannot be obtained, and the particles are Since the storage stability of the toner is impaired when it is exposed to the crushing interface, its content is 50% of all the monomers in the coating layer.
It is used in an amount of up to 30% by weight, preferably up to 30% by weight.

The layer structure of the particles of the present invention comprises 0 to 40% by weight of the core portion, 30 to 90% by weight of the rubber layer and 10 to 40% by weight of the coating layer, preferably 0 to 30% by weight of the core portion, Rubbery layer 40
-80% by weight and coating layer 15-25% by weight.

The particles of the present invention can be obtained by emulsion-polymerizing the above monomers with a water-soluble polymerization initiator in the presence of an emulsifier. Alternatively, a soap-free emulsion polymerization method without using an emulsifier may be used.

As the emulsifiers and polymerization initiators used in the emulsion polymerization of the particles of the present invention, all conventionally known emulsifiers can be used, but typical emulsifiers include sodium and potassium laurate and sodium myristate. And potassium, sodium and potassium palmitate, sodium and potassium stearate, and fatty acid salts represented by sodium and potassium oleate; N
-N-acyl amino acid salts represented by acyl-N-methylglycine sodium salt and potassium salt, N-acyl-N-methyl-β-alanine sodium salt and potassium salt, N-acyl glutamic acid sodium salt and potassium salt, and the like; Alkyl ether carboxylates represented by sodium and potassium polyoxyethylene alkyl ether acetates; alkylbenzene sulfonates such as sodium alkylbenzene sulfonate; alkylnaphthalene sulfonates; dialkylsulfosuccinate ester salts; alkylsulfoacetates; α -Olefin sulfonates; higher alcohol sulfate ester salt, secondary higher alcohol sulfate ester salt, alkyl ether sulfate, secondary higher alcohol ethoxy sulfate, polyoxyethylene alkyl sulfonate Sulfuric acid ester salts such as phenyl ether sulfates; Phosphoric acid ester salts such as alkyl ether phosphoric acid ester salts and alkyl phosphoric acid ester salts (above, anionic surfactant); Alkyltrimethylammonium chloride
Aliphatic quaternary ammonium salts such as alkyltrimethylammonium bromide and dialkyldimethylammonium chloride; benzalkonium salts such as alkyldimethylbenzylammonium chloride and alkyldimethylbenzylammonium bromide; benzethonium chloride; cetylpyridinium chloride, cetylpyridinium bromide, etc. Pyridinium salts of
Imidazolinium salts (above, cationic surfactants);
Amphoteric surfactants having a structure such as carboxybetaine, sulfobetaine, aminocarboxylic acid salt, imidazolinium betaine in the molecule; polyoxyethylene alkyl ether, polyoxyethylene secondary alcohol ether,
Polyoxyethylene alkyl phenyl ether, polyoxyethylene sterol ether, polyoxyethylene lanolin derivative, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene glycerin fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, polyethylene Glycol fatty acid ester, fatty acid monoglyceride, polyglycerin fatty acid ester, sorbitan fatty acid ester, propylene glycol fatty acid ester, fatty acid alkanolamide, polyoxyethylene fatty acid amide, polyoxyethylene alkylamine,
Nonionic surfactants such as alkylamine oxide; fluorine-based surfactants. The amount of the emulsifier added is 0 to 10% by weight, preferably 0 to
It is 3% by weight.

As the polymerization initiator, persulfates such as sodium persulfate, potassium persulfate and ammonium persulfate; 4,4'-azobis (4-cyanovaleric acid) sodium, 4,4'-azobis (4 -Cyanovaleric acid) potassium, 4,
4'-azobis (4-cyanovaleric acid) neutralizing salts of azo polymerization initiators containing carboxylic acid in the molecule such as ammonium; 2,2'-azobis (2-methyl-N-phenylpropionamidine), 2 2,2'-azobis [N- (4-chlorophenyl) -2-methylpropionamidine], 2,2'-azobis [N- (4-hydroxyphenyl) -2-methylpropionamidine], 2,2'-azobis [N- (4-aminophenyl) -2-methylpropionamidine], 2,
2'-azobis [2-methyl-N- (phenylmethyl) propionamidine], 2,2'-azobis (2-methyl-N
2-propenylpropionamidine), 2,2′-azobis (2-methyl-propionamidine), 2,2′-azobis [N- (2-hydroxyethyl) -2-methyl-propionamidine] and other azoamidine compounds And its hydrochloride, methanesulfonate, p-toluenesulfonate;
2,2'-azobis [2- (5-methyl-2-imidazolin-2-yl) propane], 2,2'-azobis [2- (2-
Imidazolin-2-yl) propane], 2,2'-azobis [2- (4,5,6,7-tetrahydro-1H-1,3-diazepin-2-yl) propane], 2,2'-azobis [2- (3,
4,5,6-Tetrahydropyrimidin-2-yl) propane], 2,2'-azobis [2- (5-hydroxy-3,4,5,
6-tetrahydropyrimidin-2-yl) propane],
2,2'-azobis [2- {1- (2-hydroxyethyl)
2-imidazolin-2-yl} propane] and the like, and cyclic azoamidine compounds and their hydrochlorides, methanesulfonates, p-toluenesulfonates and the like. The amount of the polymerization initiator added is 0.01 with respect to the monomer.
-5% by weight, preferably 0.1-2% by weight.

In the present invention, the resin particles dispersed in the polystyrene or styrene copolymer resin are
After the polymer is separated by freeze-thawing or salting out, it can be taken out as a powder by centrifugal dehydration and drying. Further, it can be pulverized with a spray dryer or a freeze dryer. Further, by adding a step of removing the water-soluble free matter remaining in the polymerization liquid by using an ion exchange resin, an ultrafiltration membrane or the like before drying, adverse effects of these impurities on the toner can be reduced. Further, after drying, it is disintegrated in the resin by crushing with a jet mill, a Henschel mixer or the like. Furthermore, the resin particles of the present invention may be used after drying as described above, or may be used in the state of an aqueous dispersion after polymerization.

The particle size of these particles is 0.01 to 2.0 μm,
Preferably 0.1 to 0.7 μm, more preferably 0.2 to 0.5
μm. If the particle size is too small, the reinforcing effect when the resin is used in the toner is not sufficiently exerted, while if it is too large, the particles are more likely to be detached from the toner. The particle size of the particles is
It can be measured by observation with a scanning electron microscope, a dynamic light scattering method, or the like.

The addition amount of the resin particles in the present invention is 0.01 to 10% by weight of the resin particles in the toner, preferably
It is 0.1 to 5% by weight. If the addition amount is too small, the reinforcing effect when added to the toner is not sufficiently exhibited, and conversely, if the addition amount is too large, the pulverizability of the toner is deteriorated during the toner production and the production efficiency is deteriorated. It must be carefully determined in consideration of the molecular weight of the styrenic copolymer resin.

The polystyrene or styrene-based copolymer resin of the present invention is synthesized by solution polymerization, suspension polymerization or emulsion polymerization. When a polystyrene or styrene-based copolymer is obtained by solution polymerization, a powdered resin is used. After the particles are dispersed in a solvent, a monomer and a polymerization initiator may be added to carry out polymerization, or the water in which the resin particles are dispersed may be replaced with a solvent or a monomer, and then the polymerization may be carried out. Further, in the case of obtaining polystyrene or a styrene-based copolymer by suspension polymerization, it is obtained by suspending dried resin particles together with a monomer and a polymerization initiator in water and polymerizing. Further, when a polystyrene or styrene-based copolymer is obtained by emulsion polymerization, dried resin particles may be dispersed in a monomer and emulsion-polymerized, but the emulsion-polymerization of the resin particles of the present invention described above is continued. However, it can be easily obtained by polymerizing the resin component which is the main component of the binder resin for toner.

In the present invention, the monomer used in the polystyrene or styrene copolymer as the main component of the binder resin for toner includes styrenes such as styrene, chlorostyrene and α-methylstyrene; ethylene, propylene,
Butylene, isobutylene, and other monoolefins; vinyl acetate, vinyl propionate, vinyl benzoate, vinyl acetate, and other vinyl esters; methyl acrylate, ethyl acrylate, butyl acrylate, octyl acrylate, dodecyl acrylate, acrylic acid Esters of α-methylene aliphatic monocarboxylic acids such as phenyl, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl butyl ether; vinyl methyl ketone, vinyl Examples thereof include vinyl ketones such as hexyl ketone and vinyl isopropenyl ketone.

The resin of the present invention is mixed with a colorant, a charge control agent, a release agent and the like and used as a toner. When the polystyrene or styrene copolymer resin of the present invention is used in a toner, the resin of the present invention is used. Not only use the resin alone,
You may use it, mixing with other resin. As the resin that can be used in combination, other styrene-based copolymers that do not contain resin particles, polyester resins, epoxy resins, polyurethane resins, silicone-based resins, fluororesins, and the like can be used. When used in combination with other resins, the resin particles in the polystyrene or styrene-based copolymer of the present invention in the pre-toner,
It is adjusted to 0.01 to 10% by weight, preferably 0.2 to 5% by weight.

[0027]

The resin particles added to the polystyrene or styrene copolymer resin of the present invention usually exhibit rubber elasticity at the temperature at which the toner is used. Therefore, by using polystyrene or a styrene-based copolymer resin, it is possible to increase the resistance of the toner to an impact force received by a charging member such as a carrier in a developing machine. Therefore, according to the present invention, it is possible to use a low-molecular-weight binder resin, which cannot be used conventionally, as a developer. Therefore, the toner using the polystyrene or the styrene-based copolymer resin of the present invention can be fixed at a low temperature, and has excellent impact resistance and stability over time.

[0028]

EXAMPLES Examples of the present invention and comparative examples will be described below, but the present invention is not limited to these examples.
All parts are parts by weight unless otherwise specified.

Synthesis Example 1 2000 parts of ion-exchanged water, dioctyl sulfosuccinate sodium salt 50% aqueous solution was placed in a 5 liter separable flask equipped with a reflux condenser, a nitrogen inlet tube and a dropping funnel.
6.4 g was charged and the temperature was raised to 80 ° C. while introducing nitrogen. Then, 30 g of methyl methacrylate and 80 g of a 2% aqueous solution of ammonium persulfate were added to initiate polymerization. Further, 10 minutes after the addition of ammonium persulfate, a monomer consisting of styrene 304 g divinylbenzene 36 g methyl methacrylate 30 g was added dropwise over 1 hour, and then at 80 ° C. for 1 hour.
It was kept warm for a time and aged. Then ammonium persulfate 2%
80 g of aqueous solution was added, and a monomer consisting of 2-ethylhexyl acrylate 1122 g divinylbenzene 18 g and methyl methacrylate 60 g was added dropwise over 3 hours, and then at 80 ° C. for 1 hour.
It was kept warm for a time and aged. Then ammonium persulfate 2%
After adding 50 g of an aqueous solution, styrene 240 g acrylonitrile 100 g divinylbenzene 60 g of the monomer was added dropwise over 1 hour, and then 1 hour at 80 ° C.
It was kept warm for a time and aged. After the reaction is complete, cool to room temperature and
The mixture was filtered through a 00 mesh wire mesh, further purified using an ion exchange resin, concentrated with an ultrafiltration membrane, and allowed to stand overnight in a 50 ° C. oven for drying. Further, the dried resin was crushed using a jet mill to obtain resin particles a of the present invention. When the obtained resin particles were observed with a scanning electron microscope, the particle size was about 300 nm. Further, when the glass transition temperature of the resin particles was measured by the DSC method, it was -65 ° C and
A transition temperature was observed at 103 ° C.

Synthesis Example 2 The same apparatus as in Synthesis Example 1 was charged with 2000 parts of ion-exchanged water and 6.4 g of a 50% aqueous solution of dioctylsulfosuccinate sodium salt, and the temperature was raised to 80 ° C. while introducing nitrogen. Next, methyl methacrylate 30g, ammonium persulfate 2%
80 g of an aqueous solution was added to initiate polymerization. Further, 10 minutes after the addition of ammonium persulfate, a monomer consisting of styrene 304 g divinylbenzene 36 g methyl methacrylate 30 g was added dropwise over 1 hour, and then at 80 ° C. for 1 hour.
It was kept warm for a time and aged. Then ammonium persulfate 2%
After adding 80 g of an aqueous solution, a monomer consisting of t-butyl methacrylate 1122 g divinylbenzene 18 g methyl methacrylate 60 g was added dropwise over 3 hours, and then at 80 ° C. for 1 hour.
It was kept warm for a time and aged. Then ammonium persulfate 2%
After adding 50 g of an aqueous solution, styrene 240 g acrylonitrile 100 g divinylbenzene 60 g of the monomer was added dropwise over 1 hour, and then 1 hour at 80 ° C.
It was kept warm for a time and aged. After completion of the reaction, resin particles b were obtained in the same manner as in Synthesis Example 1. The particle size measured in the same manner as in Synthesis Example 1 was about 290 nm. When the glass transition temperature of the resin particles was measured by the DSC method, a transition temperature was observed at 105 ° C.

Synthesis Example 3 The same apparatus as in Synthesis Example 1 was charged with 2000 parts of ion-exchanged water and 6.4 g of a 50% aqueous solution of dioctylsulfosuccinate sodium salt, and the temperature was raised to 80 ° C. while introducing nitrogen. Next, methyl methacrylate 30g, ammonium persulfate 2%
80 g of an aqueous solution was added to initiate polymerization. Further, 10 minutes after the addition of ammonium persulfate, a monomer consisting of styrene 304 g divinylbenzene 36 g methyl methacrylate 30 g was added dropwise over 1 hour, and then at 80 ° C. for 1 hour.
It was kept warm for a time and aged. Then ammonium persulfate 2%
80 g of an aqueous solution was added, and a monomer consisting of 2-ethylhexyl acrylate 1496 g divinylbenzene 24 g methyl methacrylate 80 g was added dropwise over 4 hours, and then at 80 ° C. for 1 hour.
It was kept warm for a time and aged. After completion of the reaction, filtration and purification were carried out in the same manner as in Synthesis Example 1 to obtain a dispersion liquid of resin particles c. Also, D
When the glass transition temperature of the resin particles was measured by the SC method, the transition temperatures were observed at -65 ° C and 103 ° C.

Synthesis Example 4 2000 parts of xylene was charged into a 5 liter separable flask equipped with a reflux condenser, a nitrogen inlet tube and a dropping funnel, and the temperature was raised to 90 ° C. while introducing nitrogen, and then styrene 1600 g acrylic acid A solution prepared by dispersing 60 g of the resin particles a of Synthesis Example 1 in 400 g of n-butyl and a solution of 60 g of the polymerization initiator V-59 (manufactured by Wako Pure Chemical Industries) in 300 g of xylene were added dropwise over 3 hours for polymerization. After that, 1 at 90 ℃
After keeping the temperature for a while and aging to complete the polymerization, a resin A of the present invention was obtained.
The softening temperature of Resin A measured by a high-lower flow tester was 113 ° C, and the glass transition temperature by DSC method was 62 ° C.

Synthesis Example 5 A styrene / n-butyl acrylate copolymer resin B was obtained in the same manner as in Synthesis Example 4 except that the resin particles a were not added. The softening temperature of Resin B measured by a high-lower flow tester was 111 ° C, and the glass transition temperature by DSC method was 62 ° C.

Synthetic Example 6 Synthetic Example 4 except that the resin particles a are changed to the resin particles b.
In the same manner as described above, a styrene / n-butyl acrylate copolymer resin C was obtained. The softening temperature of Resin C measured by a high-lower flow tester was 114 ° C, and the glass transition temperature by DSC method was 62 ° C.

Synthetic Example 7 2000 parts of xylene was charged in the same apparatus as in Synthetic Example 4, and the temperature was raised to 90 ° C. while introducing nitrogen. Then, 1600 g of styrene and 400 g of n-butyl acrylate were added to resin particles c of Synthetic Example 3. 60 g of resin particles from the dispersed aqueous solution
And a polymerization initiator V-59 (manufactured by Wako Pure Chemical Industries)
A solution prepared by dissolving 60 g in 300 g of xylene was added dropwise over 3 hours for polymerization, and then the mixture was kept at 90 ° C. for 1 hour for aging to complete the polymerization to obtain a resin D. The softening temperature of Resin D as measured by a high-lower flow tester was 109 ° C, and the glass transition temperature by DSC method was 59 ° C.

Example 1 Styrene / n-butyl acrylate copolymer E 20 parts (softening point 170 ° C./glass transition temperature 63 ° C.) Resin A 80 parts Carbon black 6 parts Iron azo complex (Hodogaya Chemical T-77 ) 3 parts Polypropylene wax 5 parts were premixed, melt-kneaded, pulverized with a jet mill, and then classified to obtain colored particles having an average particle diameter of 8.2 μm. To 100 parts of the colored particles, 0.4 part of Aerosil R-972 was mixed using a Henschel mixer to obtain a toner of the present invention.
An ultrathin section of this toner was prepared with a microtome and observed with a transmission electron microscope.
It was observed that the particles were evenly dispersed in the toner in units of μm.

Comparative Example 1 Styrene / n-butyl acrylate copolymer E 20 parts Resin B 80 parts Carbon black 6 parts Iron azo complex (T-77 manufactured by Hodogaya Chemical Co., Ltd.) 3 parts Polypropylene wax 5 parts Example 1 In the same manner as above, a toner having an average particle diameter of 8.1 μm was obtained.

Comparative Example 2 Styrene / n-butyl acrylate copolymer E 20 parts Resin C 80 parts Carbon black 6 parts Iron azo complex (T-77 manufactured by Hodogaya Chemical Co., Ltd.) 3 parts Polypropylene wax 2 parts Example 1 Similarly to the above, a toner having an average particle diameter of 8.3 μm was obtained.

Comparative Example 3 Styrene / n-butyl acrylate copolymer E 20 parts Resin D 80 parts Carbon black 6 parts Iron azo complex (T-77 manufactured by Hodogaya Chemical Co., Ltd.) 3 parts Polypropylene wax 2 parts Example 1 In the same manner as above, a toner having an average particle size of 8.2 μm was prepared.

Evaluation Test 122.5 g of each of the toners of Example 1 and Comparative Examples 1 to 3 and 3377.5 g of a ferrite carrier coated with a silicone resin.
Were mixed with a V blender to prepare a developer. Using this developer, fixing temperature was lowered by 15 ℃, SD-20 made by Sharp
A continuous printing test was carried out on 75 copiers (75 ppm). The fixing rate was measured by the change in density before and after the black solid was put on a rubbing tester equipped with a sand eraser. Also, put 250 g of toner in a 1 liter plastic bottle and put it in an oven kept at 50 ° C.
The toner was allowed to stand for 24 hours and the aggregation state of the toner was observed. The results are shown in Table 1.
Shown in.

[0041]

[Table 1]

As described above, the toner of the present invention does not have an adverse effect on the fixing due to the resin particles being contained in the styrene / acrylic acid ester copolymer resin, and enables low temperature fixing and is stable. Shows continuous printing durability.

On the other hand, the toner of Comparative Example 1 using the styrene / acrylic acid ester copolymer resin not containing the resin particles of the present invention has a good fixing property but a poor continuous printing durability. When the particle diameter of the toner of Comparative Example 1 was measured after the printing test, the average particle diameter was 7.3 μm, and the fraction of the fine particle portion was increased, and it is considered that the toner is destroyed. Further, in the present invention, Tg (glass transition temperature)
It was confirmed that in the case of Comparative Example 2 in which the resin particles which did not exhibit rubber elasticity at room temperature were added using a high monomer, the toner was destroyed although some effects were observed as compared with the case of no addition. It was also found that the storage stability of the toner was not ensured in the case of Comparative Example 3 in which the resin particles did not have a coating layer having a high Tg on the surface.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location 384

Claims (6)

[Claims] 1. A core layer made of an acrylic acid ester copolymer and / or a methacrylic acid ester copolymer having a glass transition temperature of 0 ° C. or lower in a polystyrene or styrene copolymer resin and having a glass transition temperature of 50 ° C. A resin composition for electrophotography, comprising the resin particles coated with the above crosslinked vinyl polymer. 2. The resin composition for electrophotography according to claim 1, wherein the core layer further has a core portion made of a vinyl polymer. 3. The resin composition for electrophotography according to claim 1, further containing another binder resin. 4. A resin in which a core layer made of an acrylic ester copolymer and / or a methacrylic ester copolymer having a glass transition temperature of 0 ° C. or lower is coated with a crosslinked vinyl polymer having a glass transition temperature of 50 ° C. or higher. A method for producing a resin composition for electrophotography, which comprises polycondensing a polystyrene or styrene copolymer resin in the presence of particles. 5. The method for producing a resin composition for electrophotography according to claim 4, wherein the core layer further has a core portion made of a vinyl polymer. 6. The resin composition for electrophotography according to claim 4, further containing another binder resin.