JPH0380260A - Resin composition for toner for electrophotography - Google Patents

Abstract

PURPOSE:To ensure superior hot offsetting resistance and fixability by incorporating a mixture of styrene-butadiene resin as an essential component with styrene-(meth)acrylate resin, etc. CONSTITUTION:This resin compsn. for a toner for electrophotography contains 30-90 wt.% styrene-butadiene resin as an essential component and 70-10 wt.% resin selected among styrene-(meth)acrylate resin, polyester resin, epoxy resin and polyurethane resin and has >=5 ratio of wt. average mol. wt. to number average mol. wt. and 40-70 deg.C glass transition point. This resin compsn. makes the hot offsetting temp. of the toner sufficiently high and the lowest fixing temp. sufficiently low.

Description

DETAILED DESCRIPTION OF THE INVENTION [F2 Field of Application] The present invention relates to a resin composition for electrophotographic toner. More specifically, the present invention relates to a resin composition for electrophotographic toner that has excellent electrical properties and fixing properties and is suitable for heat-fixing type copying machines or printers.

[Prior Art] In electrophotography, a method using a heat roll is widely used to fix an electrostatic latent image visualized with toner. In this method, it is desirable that the minimum fixing temperature 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 this hot offset temperature be high. In order to satisfy these two characteristics, it has been proposed to use styrene-butadiene resins, which have low affinity with heat rolls, in resin compositions for electrophotographic toners (for example, Japanese Patent Publication No. 57-1214
Publication No. 7).

[Problems to be Solved by the Invention] However, the electrophotographic toner resin composition made of styrene-butadiene resin used in this method does not exhibit good melting properties, In this case, the problem of not showing sufficient hot offset temperature and minimum fixing temperature occurs.

[Means for Solving the Problems] The present inventors have conducted intensive studies on a #lJ]V composition for electrophotographic toners having a sufficient hot offset temperature and minimum fixing temperature, and have finally arrived at the present invention. That is, the present invention contains 30 to 90% by weight of styrene-butadiene resin as an essential component, and contains styrene-(meth)acrylic acid ester/L resin, polyester resin, epoxy resin, and polyurethane resin. It contains 70 to io i serving% of at least one resin selected from the group consisting of, has a weight average molecular weight/number average molecular weight (Mw/Mn) of 5 or more, and a glass transition point of 40°C or more and 70°C or less. A resin composition for an electrophotographic toner, characterized in that:

Examples of the styrene-butadiene resin according to the present invention include resins made from styrene monomers, butadiene, and other monomers if necessary.

Styrene monomers include styrene, alkylstyrene (e.g. α-methylstyrene, p-methylstyrene)
etc. Among these, styrene is preferred.

Other monomers include (meth)acrylic acid ester monomers [alkyl (meth)acrylates (having a carbon number of 1 to
18, such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, etc.), hydroxyl group-containing (meth)acrylate, etc. ) acrylates (hydroxyethyl (meth)acrylate, etc.), amino group-containing (meth)acrylates (dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, etc.), vinyl esters (vinyl acetate, etc.), vinyl ethers (vinyl ethyl ether, etc.), aliphatic hydrocarbon vinyls (α-olefin, isoprene, etc.), nitrile group-containing vinyl compounds [(meth)acrylonitrile, etc.]
, N-vinyl compounds (N-vinylpyrrolidone, etc.), unsaturated carboxylic acids or their anhydrides [(meth)acrylic acid, maleic anhydride, itaconic anhydride, etc.] or two or more polymerizable functional groups in the molecule. Examples include crosslinkable monomers (divinylbenzene, ethylene glycol diacrylate, etc.) having

The content of styrenic monomer is usually 80% or more and 97% or less, preferably 85% or more and 93% based on the weight of all monomers.
It is as follows. If it is less than 80%, the toner may block when used as an electrophotographic toner and may not be able to be stored for a long period of time.

If it exceeds 97%, a sufficient minimum fixing temperature may not be obtained when used as an electrophotographic toner.

The content of butadiene is generally from 3% to 20% based on the weight of all monomers.

The amount of other monomers is typically 10% based on the weight of total monomers.
It is preferably 5% or less.

The weight average molecular weight of the styrene-butadiene resin according to the present invention is usually 5 @ 0 to 500,000, preferably 100
00-200000. Weight average molecular weight is soo.

If it is less than 100%, when a composition containing a styrene-butadiene resin is used as a toner, the toner may block and cannot be stored sufficiently for a long period of time. If the weight average molecular weight exceeds 5oooooo, a sufficient lower limit fixing temperature may not be obtained when a toner is made from a composition containing a styrene-butadiene resin.

Note that the molecular weight can be determined by gel permeation chromatography (GPC) using tetrahydrophthene as a solvent and conversion using standard polystyrene.

The styrene-butadiene resin is obtained by suspension polymerization of a styrene monomer, butadiene, and, if necessary, other monomers. When the polymerization method is an emulsion polymerization method or the like, a stable image cannot be obtained when the resulting resin is used as an electrophotographic toner due to the contamination of impurities.

Examples of the suspension polymerization method include a method in which the above-mentioned monomers, a polymerization initiator, and, if necessary, a surfactant are added to water in the presence of a dispersant and polymerized.

Dispersants include known organic dispersants (partially saponified polyvinyl alcohol, etc.) and inorganic dispersants (calcium phosphate, etc.)
etc. can be mentioned.

Examples of polymerization initiators include radical polymerization initiators that are soluble in monomers (azo initiators (azoisobutyronitrile, etc.), peroxide initiators (benzoyl peroxide, t-butylperoxyisopropyl carbonate, etc.). -1-1t-butylperoxybenzoate, etc.).

As a surfactant, alkylbenzene sulfonate,
Examples include higher fatty acid salts.

The amounts of the above components used are usually 0.1 to 100 parts by weight of a dispersant, 50 to 700 parts by weight of a monomer, 0.1 part by weight or less of a surfactant, and a polymerization initiator to 1000 parts by weight of water. , 0.01 to 20 parts by weight per 100 parts of the monomer.

Polymerization is usually carried out at 40 to 140° C. for 3 to 50 hours with the above raw materials sealed in an inert gas atmosphere. After polymerization,
By cooling and washing the obtained particles with water, styrene
Obtain a butadiene resin.

Examples of the styrene-(meth)acrylic acid ester resin according to the present invention include a copolymer of a styrene monomer, a (meth)acrylic acid ester monomer, and, if necessary, other monomers. Examples of the styrene monomer include the styrene monomers used in the styrene-butadiene resin. Among these, styrene is preferred.

Examples of the (meth)acrylic acid monomer include the (meth)acrylic acid ester monomers listed for the styrene-butadiene resin. Preferred are alkyl (meth)acrylic esters. Examples of other monomers include the other monomers used in the styrene-butadiene resin except for the (meth)acrylic acid ester monomer.

Examples of the polyester resin according to the present invention include polycondensates of polyhydric alcohols and polyhydric carboxylic acids. Examples of polyhydric alcohols include ethylene glycol, 1.2
- Diols such as propylene glycol, 1,3-propylene glycol, IJ-hexanediol, neopentyl glycol, diethyl alcohol, hydrogenated bisphenol A, polyols such as trimethylolpropane, diols, polyols, bisphenols (bisphenol A, etc.) alkylene oxide (ethylene oxide,
Propylene oxide, etc.) adducts, etc. can be mentioned. Among these, preferred is a propylene oxide adduct of bisphenol A. Examples of polyvalent carboxylic acids include aliphatic dicarboxylic acids such as malonic acid, succinic acid, and adipic acid; aromatic dicarboxylic acids and anhydrides such as phthalic anhydride, terephthalic acid, and isophthalic acid; and trimellitic acid. Polycarboxylic acids and the like can be mentioned.

As the epoxy resin according to the present invention, bisphenol A
Examples include addition condensates of and epichlorohydrin. For example, typical commercially available epoxy resins include:
Epicote 1004.1007 etc. (manufactured by Shell Chemical Co., Ltd.),
Araldite 6084.7072 etc. (CIBA fi)
, AER684 (m formation layer), etc.

Examples of the 8-point Ij urethane resin according to the present invention include polyadducts of diisocyanate components and polyhydric alcohol components. Examples of the diisocyanate component include aromatic diisocyanates such as toluene diisocyanate and diphenylmethane diisocyanate, alicyclic diisocyanates such as isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate, and aliphatic diisocyanates such as ethylene diisocyanate, tetramethylene diisocyanate, and hexamethylene diisocyanate. Among these, aromatic diisocyanates are preferred. Examples of polyhydric alcohols include diols used in the polyester resins, 1-liols, polyether polyols that are alkylene oxide (ethylene oxide, propylene oxide, etc.) adducts of bisphenol (bisphenol A, etc.), and among the polyester JM resins. Examples include polyester polyols having terminal hydroxyl groups. Among these, preferred is the propylene oxide adduct of bisphenol A.

The composition according to the present invention contains a styrene-butadiene resin and a resin selected from the group consisting of a styrene-(meth)acrylate resin, a polyester resin, an epoxy resin, and a polyurethane resin.

The content of these resins is 30 to 30% of the styrene-butadiene resin in the electrophotographic toner resin composition of the present invention.
90% by weight, preferably 40-80% by weight, styrene-
At least one resin selected from the group consisting of (meth)acrylic acid ester-based resins, polyester resins, epoxy resins, and polyurethane resins has a 70-1
0% by weight, preferably 60-20% by weight.

The mixing method of these resins is not particularly limited, and examples include melt mixing using a kneader-1 extruder, rolls, etc., mixing using a solvent and then removing the solvent, or styrene
In the presence of at least one resin selected from (meth)acrylic acid ester resin, polyurethane resin, polyester resin, and epoxy resin, styrene monomer, butadiene monomer, and other polymers if necessary. may be subjected to suspension polymerization.

The composition of the present invention may contain a polypropylene resin having an isotactic content of 75% or more and a melt viscosity of 1000 cps or less at 160° C. as a mold release agent, if necessary. The isotactic content of the polypropylene resin is preferably 80% or more. If the isotactic content is less than 75%, the fluidity of the toner decreases when used as an electrophotographic toner, and the toner may not be able to be supplied to a developing machine.

The isotactic content of the polypropylene resin used in the present invention is determined by the absorbance at 998 cm-' (D, 1g3) and the absorbance at 974 cm-' (D, 1g3) measured by an infrared spectrophotometer.
D, □4) can be obtained using the following formula.

Isotactic content (%) "D993 / D974 X100 The melt viscosity at 160° C. of the polypropylene resin used in the present invention is preferably 500 cps or less.

If the melt viscosity at 160° C. exceeds 1000 cps, a sufficient hot offset temperature may not be obtained when used in an electrophotographic toner. The melt viscosity of the polypropylene resin at 160°C is measured using a Brookfield rotational viscometer. Conditions other than the measurement temperature are based on JIS-1557-1970. An oil bath with a temperature regulator is used to adjust the temperature of the measurement sample. The content of the polypropylene resin is usually 30% by weight or less, preferably 10% by weight, based on the amount of the composition.
It is as follows. Polypropylene resin can be added during toner production into a mixture of styrene-butadiene resin, styrene-(meth)acrylate resin, polyester resin, epoxy resin, and polyurethane resin. They may also be used in premixed form.

The weight average molecular weight/number average molecular weight of the composition according to the present invention is 5 or more, preferably 7 or more.

If the weight average molecular weight/number average molecular weight is less than 5, a sufficient minimum fixing temperature and hot offset temperature cannot be obtained when used as a toner.

The glass transition point of the composition according to the present invention is 40°C or higher and 70°C.
It is as follows. If the glass transition point is below 40°C, the toner will be susceptible to agglomeration and blocking when stored for a long period of time.
If the glass transition point exceeds 70° C., the lower limit temperature for fixing is insufficient.

The resin composition for an electrophotographic toner of the present invention can be made into an electrophotographic toner by containing a colorant and various additives, if necessary.

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, cobal 1-, nickel, etc., magnetite 1-, hematite 1, ferrite 1-, etc. may be used.

Furthermore, various additives include charge control agents such as glosine and quaternary ammonium salts.

The components of the electrophotographic toner include the composition of the present invention, usually 45 to 95% by weight, preferably 70 to 90% by weight, the coloring material, usually 0.5 to 50% by weight, and the additive, usually 0.1% by weight.
-10% by weight etc. is used.

The production of toner for electrophotography is not particularly limited to the following methods, but 1) The toner components are dry blended, melt-kneaded, then coarsely pulverized, and finally pulverized using a jet pulverizer, and then Classified particle size is usually 2-2
It can also be obtained by obtaining a fine powder of 0 μm, or 2) by pulverizing the composition of the present invention to a size of 20 μm or less and fusing other components of the 1-ner (for example, a charge control agent, etc.) to the surface of the fine powder.

The electrophotographic toner described above is mixed with carrier particles such as iron powder, glass beads, nickel powder, ferrite, etc., if necessary, and used as a developer for an electrical latent image. Furthermore, hydrophobic colloidal silica fine powder can also be used to improve the fluidity of the powder.

The electrophotographic toner is heated in a heat fixing heat roll section of a copying machine, such as a heat fixing type copying machine or a printer, so that it can be applied to a support (paper, polyester film, etc.).
and is used as a recording material.

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

In the examples, all parts represent parts by weight.

Moreover, the conditions for molecular weight measurement by GPC are as follows.

Equipment: Toyo Soda Formation HLC-802A column:
TSK gel GHL62 Measurement temperature: 25°C Sample solution: 0.5% by weight THF solution Injection amount: 2
00μm Detection device: Refractive index detector Synthesis Example 1 A mixture of 900 parts of styrene and 100 parts of butadiene, 1 part of calcium hydrogen carbonate, and 30 parts of benzoyl peroxide were placed in a pressurized autoclave to prepare 0.1% of polyvinyl alcohol with a saponification degree of 89 mol%. % aqueous solution and polymerized at 60 to 85°C for 6 hours. The obtained pearly ifA fat was filtered and washed with ion-exchanged water to obtain a styrene-butadiene resin having a weight average molecular weight of ff155,000.

Synthesis Example 2 700 parts of styrene and 300 parts of butadiene were polymerized in the same manner as in Synthesis Example 1 to obtain a styrene-butadiene resin with a weight average molecular weight ff of 160,000.

Synthesis Example 3 660 parts of styrene and 1 to 340 parts of butyl acrylate were thermally polymerized at 130 to 180° C. without using a solvent or a polymerization initiator to obtain a styrene (meth)acrylic acid ester resin.

Synthesis Example 4 150 parts of terephthalic acid, 411 parts of 2,2-bis(4-hydroxyethoxyphenyl)propane, and 10 parts of trimellitic acid were subjected to a condensation reaction at 200°C to 230°C for 15 hours to obtain a polyester resin.

Example 1 70 parts of the styrene-butadiene resin of Synthesis Example 1 and 30 parts of the styrene-(meth)acrylic acid ester resin of Synthesis Example 3
and 5 parts of a polypropylene resin with an isotactic content of 85% and a melt viscosity of 80 cps at 160°C were mixed with 200 parts of toluene under heating under reflux, and the solvent was removed to obtain a molecule of ff13.
A resin composition for an electrophotographic toner of the present invention having a maximum point at 8000, a weight average molecular weight/number average molecular weight (Mw/Mn) of 8, and a glass transition point of 60° C. was obtained.

Example 2 70 parts of the styrene-butadiene resin of Synthesis Example 1, 30 parts of the polyester resin of Synthesis Example 4, and 5 parts of a polypropylene resin with an isotactic content of 85% and a melt viscosity of 80 cps at 160°C were added to 200 parts of toluene. Mix under heating under reflux, remove solvent, and calculate weight average molecular weight/number average molecular m (M
w/Mn) is 11. A resin composition for electrophotographic toner of the present invention having a glass transition point of 65° C. was obtained.

Example 3 Mixed in the same manner as in Example 2 except for using the polyester resin epoxy resin Epikote 1004, and the Mw/M
A resin composition for electrophotographic toner of the present invention having n of 7 and a glass transition point of 55° C. was obtained.

Example 4 30 parts of the polyester resin of Example 2 was mixed in the same manner except that 10 parts of the polyurethane resin Pandex T-5205 (manufactured by Dainippon Ink Co., Ltd.) was used, and Mw/Mn was 8.
A resin composition for electrophotographic l-ner of the present invention having a glass transition point of 50° C. was obtained.

Comparative Example 1 The styrene-butadiene resin of Synthesis Example 1 was used as the electrophotographic toner resin composition of Comparative Example 1. Comparative Example 2 The styrene-butadiene resin of Synthesis Example 1 described in Example 2 was used as the styrene of Synthesis Example 2. -Mixed in the same manner except for using butadiene resin, Mw/Mn 10, glass transition point 35
A resin composition for an electrophotographic toner was obtained.

Use Example 1 An electrophotographic toner was prepared using the composition of Example 1 in the following manner. Furthermore, an electrophotographic developer was produced.

Toner production method Resin composition for electrophotographic toner 87 parts Polypropylene resin 4 parts (Sanyo Kasei Co., Ltd. Il Viscoel 660P) (Isotactic content 86%) (Melt viscosity at 160°C 70 CPS) Carbon black 8 parts ( MA manufactured by Mitsubishi Chemical Industries, Ltd.
-100) Charge control agent 1 part (
Spiron Black TRI (manufactured by Hodogaya Chemical Industry Co., Ltd.) The above formulation was powder blended, then kneaded in a Labo Plastomill at 140°C and 30 rpm for 10 minutes, and the kneaded material was milled in a jet mill PJM100 (Japan Pneumatic Co., Ltd.). vIX pulverization. Fine powder of 2μ or less was cut from the finely pulverized material using a powder airflow classification a1MsD (Japan Pneumatic Co., Ltd.).Aerosil R9 was added to 1000 parts of the obtained powder.
72 (Nippon Aerosil) were uniformly mixed to obtain a toner.

git agent production method A developer was obtained by mixing 25 parts of toner with 1000 parts of carrier iron powder for electrophotography (F-100 manufactured by Nippon Tetsuko Co., Ltd.).

Use Examples 2 to 4, Comparative Use Example 1.2 The resin composition for electrophotographic toner of Example 1 of Use Example 1 was used as the resin composition for electrophotographic toner of Examples 2 to 4 and Comparative Examples 1 and 2. A developer was obtained in the same manner except for the following.

Table 1 shows the evaluation results for each developer.

Table-1 Developer evaluation results Fixation lower limit Using a commercially available heat-fixing copier, The residual rate after peeling off cellophane tape is Evaluation was made at a heat roll temperature of 40%.

81 Less than 20℃ G 120'C or more and less than 140℃ P 140℃
The hot offset property was evaluated using a commercially available heat-fixing type copying machine and the temperature of the P1-roll at which 1-1 to 100% of hot offset was generated.

E: 200°C or higher 0: 180°C or higher: 200°C or higher: Lower than 2,180°C The resin composition for electrophotographic toner contains a styrene-butadiene resin, a styrene-(meth)acrylic acid ester resin, and a polyester tea tree resin as essential components.
It is a mixture with at least one resin selected from the group consisting of , epoxy resin, and polyurethane resin. Electrophotographic toner containing this mixture not only has excellent hot offset resistance but also has a low fixing temperature lower limit. It was confirmed that the storage stability was low and the storage stability was excellent.

[Effect of the invention]

Claims (1)

[Claims] 1. Styrene-butadiene resin as an essential component.
0 to 90% by weight, and 70 to 10% by weight of at least one resin selected from the group consisting of styrene-(meth)acrylic acid ester resins, polyester resins, epoxy resins, and polyurethane resins. Then,
A resin composition for an electrophotographic toner, which has a weight average molecular weight/number average molecular weight (Mw/Mn) of 5 or more and a glass transition point of 40°C or more and 70°C or less. 2. The composition according to claim 1, wherein the styrene-butadiene resin is obtained by a suspension polymerization method, has a styrene content of 80% by weight or more and 97% by weight or less, and a weight average molecular weight of 5,000 to 500,000. 3. The composition according to claim 1 or 2, which contains a polypropylene resin having an isotactic content of 75% or more and a melt viscosity at 160° C. of 1000 cps or less as a mold release agent.