JP3192744B2 - Resin composition for toner and toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin for a toner used in electrophotography and the like, and more particularly, to a resin composition for a toner used in a so-called dry development method among methods for developing an electrostatic image. And a toner using the same.

[0002]

2. Description of the Related Art In a dry development system, toner is usually charged by friction with iron powder or glass beads called a carrier, and this is attached to an electrostatic latent image on a photoreceptor by electric attraction, and then the toner is charged. Transferred to paper,
The image is fixed by a heat roll or the like to form a permanent visible image. As a fixing method, a heating roller method is used in which a toner image of a sheet to be fixed is passed through the surface of a heating roller having a surface formed of a material having releasability to toner while applying pressure thereto. Is often used. In the heating roller method, a resin for toner that can be fixed at a lower temperature is required in order to improve economy such as power consumption and to increase copying speed.

From the viewpoint of low-temperature fixability, it has been proposed to lower the molecular weight of a vinyl copolymer in a resin composition for a toner. However, although these methods certainly improve the fixability of the toner, a part of the toner that forms an image at the time of fixing is transferred to the surface of the heat roller, and the toner is again applied to the next sheet. There is a problem that the phenomenon (offset) of shifting and soiling the image is likely to occur, and there is a problem that the toner is likely to aggregate. For the purpose of solving these problems, Japanese Patent Application Laid-Open No. 56-15834
No. 0 and JP-A-58-202455,
A technique has been proposed in which the resin of the toner is composed of a resin composed of a low molecular weight polymer component and a high molecular weight polymer component.

[0004]

However, such a conventional toner has a low toughness of the resin, so that when a fixed material is rubbed, a white background portion on which no toner is deposited is stained, that is, a so-called white background stain is caused. was there. In order to increase the toughness of the resin, it is conceivable to crosslink the resin or add rubber, but in the method of adding crosslinkage or rubber, the dispersibility becomes poor, fogging occurs, or the cohesiveness is poor. This causes a problem of becoming distorted.

SUMMARY OF THE INVENTION An object of the present invention is to provide a resin composition for a toner having the following characteristics and a toner containing the same. Does not cause stains on white background. Excellent low-temperature fixability. Excellent offset resistance. Excellent non-aggregation properties. There is no fog in the image.

[0006]

The resin composition for a toner of the present invention is a vinyl copolymer containing a styrene monomer and / or a (meth) acrylate monomer as a constitutional unit, Maximum value of molecular weight distribution is 4 × 10 ³ -8
Ethylene or propylene and ethylene into a vinyl copolymer containing a low molecular weight polymer component of × 10 ⁴ and a high molecular weight polymer component having a maximum molecular weight distribution of 2 × 10 ⁵ to 2 × 10 ^6. And 0.5 to 15% by weight of a copolymer having a molecular weight of 200,000 or more and 1,000,000 or less obtained by copolymerizing an α-olefin other than propylene.

[0007] The vinyl copolymer used in the present invention contains a styrene monomer and / or a (meth) acrylate monomer as a constitutional unit. In addition to these monomers, other vinyl monomers can be included as constituent units. Specific examples of the styrene monomer in the present invention include, in addition to styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α
-Methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-ter-
Butylstyrene, pn-hexylstyrene, pn-
Octyl styrene, pn-dodecyl styrene, p-methoxy styrene, p-phenyl styrene, p-chlorostyrene, 3,4-dichlorostyrene and the like can be mentioned.

Specific examples of the acrylate or methacrylate monomer in the present invention include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-octyl acrylate, Dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, stearyl methacrylate, etc. In addition to the alkyl esters of acrylic acid or methacrylic acid, 2-chloroethyl acrylate, phenyl acrylate, α-methyl methyl acrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, Diethylaminoethyl acrylic acid,
2-hydroxyethyl methacrylate, glycidyl methacrylate, bisglycidyl methacrylate, polyethylene glycol dimethacrylate, methacryloxyethyl phosphate, and the like, and examples thereof include ethyl acrylate, propyl acrylate, butyl acrylate, methyl methacrylate, and ethyl methacrylate. , Propyl methacrylate, butyl methacrylate and the like are particularly preferably used.

Other vinyl monomers in the present invention include acrylic acid such as acrylic acid, methacrylic acid, α-ethylacrylic acid and crotonic acid and α- or β-alkyl derivatives thereof, fumaric acid, maleic acid, Examples thereof include unsaturated dicarboxylic acids such as citraconic acid and itaconic acid and monoester derivatives and diester derivatives thereof, monoacryloyloxyethyl succinate, monomethacryloyloxyethyl succinate, acrylonitrile, methacrylonitrile, and acrylamide.

In the present invention, the vinyl copolymer is characterized by further containing a low molecular weight polymer component and a high molecular weight polymer component. Therefore, the vinyl copolymer of the present invention has at least two peaks in a molecular weight distribution curve measured by gel permeation chromatography (GPC) due to the inclusion of a low molecular weight polymer component and a high molecular weight polymer component. It is formed. In the present invention, the maximum value of the molecular weight distribution of the low molecular weight polymer component is 4 × 10 ³ to 8 × 10 ⁴ , and the maximum value of the molecular weight distribution of the high molecular weight polymer component is 2 × 10 ⁵ to 2 × 10 4. ⁶
It is. If the maximum value of the molecular weight distribution of the low molecular weight polymer component is smaller than the above range, the cohesiveness may be deteriorated, and if it is larger than the above range, the fixability may be reduced.

If the maximum value of the molecular weight distribution of the high molecular weight polymer component is smaller than the above range, the offset resistance may be deteriorated, and if it is larger than the above range, the fixing property may be reduced. is there. In such a vinyl copolymer, the content of the high molecular weight polymer component is preferably 15% by weight or more. When the content of the high molecular weight polymer component is less than 15% by weight, the offset resistance may decrease. Further, the polymer in the present invention preferably has a glass transition point of 50 ° C. or higher from the viewpoint of cohesiveness.

In the present invention, 0.5 to 15% by weight of a copolymer of ethylene or propylene and an α-olefin is contained with respect to the above-mentioned vinyl copolymer. When the content of the copolymer is less than 0.5% by weight, the effects of the present invention such as improvement of white background stains are hardly obtained. On the other hand, if the content exceeds 15% by weight, fusing or the like occurs due to poor fixability or poor dispersion. A more preferred content of these copolymers is 1 to 10% by weight.

In the present invention, the copolymer of ethylene or propylene and an α-olefin is a polymer obtained by copolymerizing ethylene or propylene with an α-olefin, and the component of ethylene or propylene is 50 mol% or more. Is preferred. Further, when the amount of the α-olefin component is extremely small, crystallinity may be increased and dispersibility with the vinyl copolymer may be deteriorated. Therefore, it is preferable that the α-olefin component is contained in an amount of 5 mol% or more. The α-olefin of the copolymer is an α-olefin other than ethylene and propylene. For example, butene, pentene, hexene, methylpentene and the like can be used, butene is particularly preferred. This copolymer is different from wax having a molecular weight of about 3000 which is usually blended in a toner, and has a molecular weight of 200,000 to 1 in view of toughness.
It is less than one million.

Styrene monomer and / or (meth)
As the constitution of the above-mentioned vinyl copolymer containing an acrylic acid ester monomer as a constitutional unit, suspension polymerization, emulsion polymerization, solution polymerization, bulk polymerization and the like can be used. Various methods can be adopted as a method for adding a copolymer of ethylene or propylene and an α-olefin to the vinyl copolymer. For example, a vinyl copolymer and α
-A method in which the olefin copolymer and the olefin copolymer are melted by heat and blended can be adopted. In order to make the content more homogeneous, it is preferable to disperse each copolymer in a solvent and then remove the solvent. More preferably, the vinyl copolymer is polymerized in the presence of the α-olefin copolymer.

In the resin composition for a toner of the present invention,
Vinyl acetate, vinyl chloride, ethylene, and the like can be copolymerized with the vinyl copolymer as long as the objects and effects of the present invention can be achieved. Further, a polymer of these monomers may be blended with the vinyl copolymer. Further, a polyester resin or an epoxy resin may be mixed. Further, an aliphatic amide, a bisaliphatic amide, metal soap, paraffin and the like may be mixed.

Further, as long as the objects and effects of the present invention can be achieved, dyes such as nigrosine and spiron black (manufactured by Hodogaya Chemical Co., Ltd.) and other phthalocyanine pigments may be added as charge controlling agents. Can be. Further, as a coloring agent, carbon black, chrome yellow, aniline blue, or the like can be used. Further, low molecular polyethylene, polypropylene wax or the like may be added as a release agent, or hydrophobic silica or the like may be added to increase fluidity. To produce a toner by using the resin composition for a toner of the present invention, a conventionally known toner additive such as the above-described colorant is blended with a ribbon blender,
A method of mixing with a Hensel mixer or the like, kneading the mixture with a roll mill, a kneader, an extruder or the like, and then cooling and finely pulverizing can be adopted.

[0017]

The resin composition for a toner of the present invention comprises a vinyl copolymer containing a low-molecular-weight polymer component and a high-molecular-weight polymer component as described above. Excellent in offset properties. Further, according to the present invention, the α-olefin copolymer having a molecular weight of 200,000 to 1,000,000 which is tough and easily dispersed in the vinyl copolymer is contained at a specific ratio of 0.5 to 15% by weight. As a result, the toughness of the resin composition for a toner is enhanced, and a toner that does not cause white background staining or image fog and hardly aggregates can be obtained.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Example 1 72 parts by weight of styrene, methyl methacrylate 10
Parts by weight, polymerized 18 parts by weight of n-butyl acrylate,
A resin as a high molecular weight polymer component was obtained. This high molecular weight polymer component has a maximum molecular weight distribution of 400,000 (4 ×
10 ⁵ ). 135 g of the resin as a polymer component having a high molecular weight and 25 g of an ethylene-butene copolymer (manufactured by Mitsui Petrochemical Co., Ltd., trade name: Tuffmer AA-4085: molecular weight of about 200,000) as an α-olefin copolymer The mixture was placed in a 3 liter separable flask, dissolved with 1 liter of xylene, and the gas phase was replaced with nitrogen gas.
The system was warmed to the boiling point of xylene.

With the xylene refluxed, a mixture of 227 g of styrene, 31 g of methyl methacrylate, 57 g of n-butyl acrylate and 9 g of BPO as a polymerization initiator was stirred for 2.5 hours while stirring. While dropping, solution polymerization was performed to polymerize the low molecular weight polymer component in the presence of the high molecular weight polymer component and the α-olefin copolymer. After completion of the dropwise addition, the mixture was aged for 1 hour while stirring at a temperature at which xylene boils. Thereafter, while gradually raising the temperature of the system to 180 ° C., xylene was desolvated under reduced pressure. As described above, a resin A containing a low molecular weight polymer component having a molecular weight distribution peak of 10,000 (1 × 10 ⁴ ) was obtained. The glass transition point of this resin A was 62 ° C. In the resin A, the content of the ethylene / butene copolymer as the α-olefin copolymer is as follows:
It is about 5.3% by weight.

100 parts by weight of the resin A, 5 parts by weight of carbon black (trade name: MA-100, manufactured by Mitsubishi Kasei Co., Ltd.), 1 part by weight of SPIRON BLACK TRH, and PP wax (trade name: VISCOL, manufactured by Sanyo Chemical Co., Ltd.) 660P) were melt-blended, cooled, coarsely pulverized, and then finely pulverized with a jet mill to produce a toner powder having an average particle size of about 12 to 15 microns. A hydrophobic silica powder (manufactured by Nippon Aerosil Co., Ltd., trade name: R-97) is added to this toner powder.
2) A toner was prepared by adding 0.3 parts by weight. After 10 g of the toner was placed in a 100 ml sample bottle and left in a thermostat at 50 ° C. for 16 hours, the degree of aggregation was measured with a powder tester (manufactured by Hosokawa Micron Corporation). As a result, no aggregation was observed.

Further, 4 parts by weight of the toner is added to about 50-80.
A developer was prepared by mixing with 96 parts by weight of an iron powder carrier having an average particle size of microns, and a copy was obtained using the developer. The electrophotographic copying machine used was DC-40 manufactured by Mita Corporation.
85. The fixing temperature was set at a value at which the density of a copied image changes when the copy is rubbed with a sand eraser for a typewriter while variously changing the set temperature of a heat roller of an electrophotographic copying machine. The fixing temperature of the developer using the resin A is 1
It was sufficiently low at 50 ° C. The offset occurrence temperature was set to a set temperature at which an offset was generated by variously changing the set temperature of the heat roller of the electrophotographic copying machine. The offset generation temperature of the developer using the resin A was 200 ° C. or higher, which was sufficiently high. Further, no fog was observed in the image fixed at 170 ° C., and no stain on a white background was observed even when the image was rubbed with gauze.

[0022]

[0023]

[0024]

[0025]

Example 2 30 g of a propylene-butene copolymer (manufactured by Mitsui Petrochemical Co., Ltd., trade name: Tuffmer XR XR107L: molecular weight of about 200,000) in a 3-liter separable flask and styrene 310 g, acrylic acid n
-120 g of butyl, 700 g of toluene, and Kayaester HTP as a catalyst (manufactured by Kayaku Nouri) 0.3
g, and the gas phase was replaced with nitrogen gas, and the system was heated to the boiling point of toluene. In a state where the reflux of toluene occurred, the resin serving as a high molecular weight polymer component was polymerized while stirring for 10 hours. Then, 450 g of styrene, 100 g of butyl methacrylate, and AIBN1
Solution polymerization was carried out while dropping 0 g of the mixture over 2 hours to produce a resin corresponding to a low molecular weight polymer component. After completion of the dropwise addition, the mixture was aged for 3 hours while stirring at a temperature at which toluene was boiling. Thereafter, the temperature of the system is set to 180
The solvent was removed from the toluene under reduced pressure while gradually increasing the temperature to ℃ to obtain a resin B having a maximum molecular weight distribution of 20,000 (2 × 10 ⁴ ) and 250,000 (2.5 × 10 ⁵ ). The glass transition point of this resin B was 58 ° C. The content of the propylene-butene copolymer, which is an α-olefin copolymer, was about 4.3% by weight. 100 parts by weight of the resin B obtained as described above, 5 parts by weight of carbon black (manufactured by Mitsubishi Kasei Corporation, trade name: MA-100), 1 part by weight of Spiron Black TRH, and PP wax (manufactured by Sanyo Chemical Industries, Ltd.) And 3 parts by weight of Viscol 660P (trade name) were melt-blended, cooled, roughly pulverized, and then finely pulverized with a jet mill to prepare a toner powder having an average particle size of about 12 to 15 microns.

A toner was prepared by adding 0.3 parts by weight of hydrophobic silica powder to this toner powder in the same manner as in Example 1. The toner was measured for the degree of aggregation, and no aggregation was observed. . Also, in the same manner as in Example 1,
A developer was prepared by mixing 96 parts by weight of the iron powder carrier with 4 parts by weight of the toner, and the fixing temperature and the offset occurrence temperature of the developer were evaluated.
The temperature was 0 ° C., which was sufficiently low. The offset generation temperature was 200 ° C. or higher, which was a sufficiently high temperature. Further, no fog was observed in the image fixed at 170 ° C.
No white background stains were seen when rubbed with gauze.

Comparative Example 1 A developer was prepared and tested in the same manner as in Example 1 except that the ethylene-butene copolymer was not used. As a result, no cohesion was observed. The temperature was 150 ° C., the offset occurrence temperature was 200 ° C. or higher, and no fog was observed in the fixed image at 170 ° C. However, white background staining was observed when rubbed with gauze.

Comparative Example 2 In Example 1, 1 g of divinylbenzene was added as a crosslinking agent to a low molecular weight polymerization solution without using an ethylene-butene copolymer, and the peak of the molecular weight distribution of the low molecular weight polymer component was reduced. A resin of 20,000 (2 × 10 ⁴ ) was obtained. The glass transition point of this resin was 63 ° C. A developer was prepared using this resin in the same manner as in Example 1, and a test was conducted. As a result, no cohesiveness was observed and no fog was observed in the image. When rubbed with gauze, no white background stain was observed, and the offset generation temperature was 200 ° C. or higher. However, the fixing temperature was 170 ° C., which was higher than that of the example according to the present invention.

Comparative Example 3 A developer was prepared in the same manner as in Example 1 except that polyethylene having a molecular weight of about 50,000 (5 × 10 ⁴ ) was used instead of the ethylene-butene copolymer. Made,
Tested. As a result, no cohesiveness was observed, the fixing temperature was 150 ° C., and the offset occurrence temperature was 200 ° C.
° C or higher. However, fog was observed in the image fixed at 170 ° C., and white background stain was observed when rubbed with gauze.

Comparative Example 4 The procedure of Example 1 was repeated except that the ethylene-butene copolymer was replaced by 0.4%.
A developer was prepared and tested in the same manner as in Example 1, except that 99.6% by weight of a low molecular weight polymer component was used. As a result, no cohesiveness was observed, the fixing temperature was 140 ° C., and no change was observed in the image. However, the offset generation temperature was as low as 160 ° C., and white background stain was observed when rubbed with gauze.

Comparative Example 5 80 parts by weight of styrene, methyl methacrylate 10
By weight, 10 parts by weight of 2-ethylhexyl acrylate was polymerized to obtain a resin as a low molecular weight polymer component. The maximum value of the molecular weight distribution of this resin was 5,000 (5 × 10 ³ ). Further, 80 parts by weight of styrene and 20 parts by weight of butyl methacrylate were polymerized to obtain a high molecular weight polymer component. The maximum value of the molecular weight distribution of this resin is 800,000 (8 × 1
0 ⁵ ). 70% by weight of the low molecular weight polymer component, 23% by weight of the high molecular weight polymer component, and α-
7% by weight of high styrene rubber (manufactured by Nippon Synthetic Rubber Co., Ltd.) having 30% by weight of a rubber component as an olefin copolymer is mixed, and the mixture is placed in a 3-liter separable flask and dissolved with 1-liter of xylene. After replacing the phase with nitrogen gas, the system was warmed to the boiling point of xylene. The mixture was stirred for 2 hours while xylene was refluxed. afterwards,
The xylene was desolvated under reduced pressure while gradually raising the temperature of the system to 180 ° C., to obtain a resin C having a glass transition point of 60 ° C. In this resin C , the content of the high styrene rubber in which the rubber component as the α-olefin copolymer was 30% by weight was about 7% by weight. 100 parts by weight of the resin B obtained as described above, 5 parts by weight of carbon black (manufactured by Mitsubishi Kasei Corporation, trade name: MA-100), 1 part by weight of Spiron Black TRH, and PP wax (manufactured by Sanyo Chemical Co., Ltd.)
The product was melt-blended with 3 parts by weight of biscol 660P), cooled, roughly pulverized, and then finely pulverized with a jet mill to prepare a toner powder having an average particle size of about 12 to 15 microns. 0.3 parts by weight of hydrophobic silica powder (trade name: R-972, manufactured by Nippon Aerosil Co., Ltd.) was added to this toner powder to prepare a toner. 10 g of this toner is 100
The sample was taken in a ml sample bottle, left in a thermostat at 50 ° C. for 16 hours, and then measured for agglomeration with a powder tester (manufactured by Hosokawa Micron Corporation). As a result, no agglutination was observed. In the same manner as in Example 1, 4 parts by weight of this toner and 96 parts by weight of an iron powder carrier were mixed to prepare a developer, and the fixing temperature and the offset occurrence temperature were evaluated. As a result, although the fixing temperature was 200 ° C. or higher, cohesion was observed, and the fixing temperature was 170 ° C., fogging was observed on the image, and white background stain was observed when rubbed with gauze.

Comparative Example 6 In Example 2 , 30 g of a propylene-butene copolymer was used.
A developer was prepared in the same manner as in Example 2 , except that 250 g was used instead of. In Comparative Example 6, the content of the propylene-butene copolymer was about 25.2.
%, Which is outside the scope of the present invention. A test was carried out in the same manner as in Example 3 using the developer obtained as described above. As a result, no cohesiveness was observed, and the offset occurrence temperature was 200 ° C. or higher, but the fixing temperature was 17 ° C.
The temperature was 0 ° C., fogging was observed on the image, and white background stain was observed when rubbed with gauze.

[0034]

As described above, the resin composition for a toner of the present invention uses a vinyl copolymer containing a low molecular weight polymer component and a high molecular weight polymer component.
The low-temperature fixing property and the offset resistance are improved. Also,
In the present invention, such a vinyl-based copolymer contains a copolymer of ethylene or propylene and an α-olefin at a specific ratio. The toughness of the composition is increased, white background stain and image fog can be improved,
A toner that does not easily aggregate can be obtained.

Continuation of front page (56) References JP-A-3-122660 (JP, A) JP-A-1-225963 (JP, A) JP-A-62-116063 (JP, A) JP-A-4-81863 (JP) JP-A-3-64765 (JP, A) JP-A-2-275962 (JP, A) JP-A-56-16144 (JP, A) JP-A-56-110951 (JP, A) 1-204058 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G03G 9/08

Claims (2)

(57) [Claims] 1. A vinyl copolymer containing a styrene monomer and / or a (meth) acrylate monomer as a constitutional unit, wherein the maximum value of the molecular weight distribution is 4 × 1.
A vinyl-based copolymer containing a low-molecular-weight polymer component having a molecular weight distribution of 0 ³ to 8 × 10 ⁴ and a high-molecular-weight polymer component having a maximum molecular weight distribution of 2 × 10 ⁵ to 2 × 10 ⁶ , Or a resin composition for toner containing 0.5 to 15% by weight of a copolymer having a molecular weight of 200,000 to 1,000,000 obtained by copolymerizing propylene and ethylene and an α-olefin other than propylene. object. 2. A toner comprising a colorant and a resin composition for toner as main components, wherein the resin composition for toner is the resin composition for toner according to claim 1.