JP3077860B2 - Toner composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner composition. More specifically, the present invention relates to a toner composition for developing an electrostatic latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method, or the like.

[0002]

2. Description of the Related Art In electrophotography, as a method for permanently fixing a toner image formed on an image receiving sheet onto a sheet, a heating roller fixing method is widely used. According to this method, since the surface of the heating roller and the image surface of the sheet to be fixed come into pressure contact with each other, the toner image is excellent in heat efficiency when heat-welding the sheet to the sheet to be fixed, and quick fixing can be performed. Very suitable. However, although this method has the advantages described above, it has a serious problem that an offset phenomenon occurs. This is a phenomenon in which a part of the toner that forms an image at the time of fixing adheres to the surface of the heat roller and transfers to the next sheet to be fixed, thereby soiling the image.

As a countermeasure to prevent the offset phenomenon,
In addition to selecting the material of the roller, apply a silicone oil or the like as a release agent to the heat roller, or include a low softening point wax such as low molecular weight polypropylene, low molecular weight polyethylene, or paraffin wax in the toner as a release agent. In order to increase the cohesive force between the molten toners, measures such as broadening the molecular weight distribution have been taken.

In recent years, low power consumption and high-speed fixing have been desired in the heating roller fixing method. On the other hand, it is said that lowering the Tg of the toner binder resin and lowering the melt viscosity are effective. I have. However, a decrease in Tg of the toner binder resin is caused by a decrease in storage stability such as blocking,
Further, this causes a decrease in the fluidity of the toner, and the low melt viscosity makes the offset phenomenon more remarkable.

In order to solve these problems, for example,
JP-A-2-5071 discloses that a crystalline acrylate or an oligomer of a crystalline methacrylate containing a monomer such as stearyl acrylate or stearyl methacrylate as a constituent unit is added to the toner composition. Has been proposed. No. 4
No. 514487 discloses a toner similarly obtained by polymerizing a polymerizable monomer constituting a binder resin in the presence of an oligomer of stearyl acrylate or an oligomer of a copolymer containing stearyl acrylate.

Certainly, such oligomers such as crystalline acrylic acid ester or crystalline methacrylic acid ester have a low melting point and a low melt viscosity, so that it is possible to lower the minimum fixing temperature of the obtained toner. . However, during the production of the toner, when these oligomers are added and melt-kneaded in the toner binder resin, the difference in melt viscosity between the toner binder resin and the oligomer is large, so that Is insufficiently dispersed, and the domain of the oligomer present in the matrix of the toner binder resin becomes relatively large. As described above, when the dispersion domain of the oligomer in the toner particles is large, the manifestation of the offset resistance due to the presence of the oligomer is not sufficient, and the decrease in the fluidity and the decrease in the blocking resistance are reduced. In addition, problems such as slow rise of charging of the toner due to a decrease in fluidity occur.

[0007]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an improved toner composition. Another object of the present invention is to provide a toner composition capable of obtaining a toner excellent in offset resistance, fluidity, chargeability and storage stability.

[0008]

SUMMARY OF THE INVENTION The above objects are as follows.
The toner composition containing at least a toner binder resin and a colorant has a weight average molecular weight of 35,000 to 50,000.
0 crystalline acrylate polymer and / or crystalline methacrylate polymer of 0.5 to 3
It is achieved by containing 0% by weight.

In the electrostatic charge developing toner of the present invention, the crystalline acrylate polymer and / or
Or with the crystalline methacrylic acid ester-based polymer
The melting point temperature is 100 cP or more at 140 ° C.
Things are used.

[0010]

As described above, in the present invention, the toner composition contains 0.5 to 30% by weight of a crystalline acrylate polymer and / or a crystalline methacrylate polymer having a weight average molecular weight of 35,000 to 500,000. Things. Weight average molecular weight of 35,000 to 50
0000 crystalline acrylate polymer and / or
Alternatively, the methacrylate polymer has a melting point
Conventionally, it is considerably lower than polyolefin wax used as a wax component,
Since the affinity with the toner binder resin is higher than that of the polyolefin-based wax, when the toner is manufactured by the pulverization method, the toner is easily dispersed in the binder resin and has a high dispersibility.

Further, as described above, the crystalline acrylate polymer and / or the crystalline methacrylate polymer contained in the toner composition according to the present invention has a relatively low melting point. Since it has a long-chain alkyl group, it has high releasability and good offset resistance of the toner. As described above, in the toner particles having the composition according to the present invention, the crystalline acrylate polymer and / or the crystalline methacrylate polymer have good dispersibility and their domains are sufficiently small. Therefore, there is almost no influence of the crystalline acrylate polymer and / or the crystalline methacrylate polymer on the fluidity of the toner particles, and the fluidity is good, so that the rise of the charge is good. .

Hereinafter, the present invention will be described in more detail based on embodiments. The crystalline acrylate-based polymer and / or the crystalline methacrylate-based polymer used in the toner for electrostatic charge development of the present invention contains, for example, a monomer represented by the following general formula (I) as a structural unit. , Preferably 100 to 50 mol%, more preferably 100 to 60 mol%, even more preferably 100 to 50 mol%.
One containing 70 mol% is exemplified.

[0013]

Embedded image

Specific examples of the monomer represented by the above general formula (I) include, for example, stearyl acrylate, stearyl methacrylate, hexadecyl acrylate, hexadecyl methacrylate, heptadecyl acrylate, heptadecyl methacrylate, nonadecyl acrylate , Nonadecyl methacrylate, aralkyl acrylate, aracryl methacrylate, behenyl acrylate, behenyl methacrylate, pentasil acrylate, pentasil methacrylate, heptayl acrylate, heptacil methacrylate, nonacil acrylate, nonacil methacrylate, doteracyl acrylate, methacrylic And acid doteriacil. Among them, particularly preferably, stearyl acrylate, stearyl methacrylate, behenyl acrylate, behenyl methacrylate,
Pentasil acrylate and pentasil methacrylate;

Examples of the monomer copolymerizable with the monomer represented by the general formula (I) include, for example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene and α-methylstyrene. -Methylstyrene, p-methoxystyrene, p-tert-butylstyrene, p-phenylstyrene, o-chlorostyrene, m-chlorostyrene, p
Styrene monomers such as chlorostyrene; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, dodecyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, α-chloro Methyl acrylate, ethyl methacrylate, propyl methacrylate, n-methacrylic acid
Non-crystalline acrylate or non-crystalline methacrylate monomers such as butyl, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate; acrylonitrile, methacrylonitrile, acrylamide and the like Acrylic acid monomers; vinyl ether monomers such as vinyl methyl ether, vinyl isobutyl ether and vinyl ethyl ether; vinyl ketone monomers such as vinyl methyl ketone, vinyl ethyl ketone and vinyl hexyl ketone; N-vinyl pyrrole, N-vinyl carbazole, N
N-vinyl compound monomers such as vinylindole and N-vinylpyrrolidone; and various vinyl monomers such as ethylene, propylene, butylene, vinyl chloride, and vinyl acetate.

The weight average molecular weight of such a crystalline acrylate polymer and / or a crystalline methacrylate polymer is 35,000 to 5
00000, more preferably 45,000 to 45000
0, more preferably about 55,000 to 400,000. That is, when the weight average molecular weight is less than 35,000, the melting point is low and the melt viscosity is low, so the difference in melt viscosity between the toner binder resin and the oligomer is large, and the The dispersion of the oligomer becomes insufficient, and the domain of the oligomer present in the matrix of the toner binder resin is likely to be relatively large, while the weight average molecular weight exceeds 500,000. This is because there is a high possibility that the melt viscosity is high, the melting properties are reduced, and the offset resistance is reduced.

The melt viscosity of such a crystalline acrylate polymer and / or a crystalline methacrylate polymer at 140 ° C. is 100 cP or more, more preferably 150 to 50,000 cP or more, and most preferably 200 to 40,000 cP. It is desirable. The melt viscosity is a viscosity at 140 ° C. measured by a B-type viscometer.

In the electrostatic charge developing toner of the present invention, such a crystalline acrylic acid ester polymer and / or crystalline methacrylic acid ester-based polymer is used in a toner composition containing at least a binder resin and a colorant as described below. In which 0.5 to 30% by weight, more preferably 1 to 30% by weight.
-15% by weight. If the amount is less than 0.5% by weight, it is difficult to sufficiently improve the offset resistance of the obtained toner, while the amount is 30% by weight.
If the ratio exceeds the range, there is a great possibility that the thermal fixability, the fluidity, and the rise of charge of the toner may be reduced.

As the binder resin used in the toner for developing an electrostatic charge of the present invention, various resins conventionally used in such a toner can be used. Copolymers, polyester resins and the like are preferable, and among them, styrene resins or styrene / acrylic resins are particularly preferable.

As the polyester resin, as a polyol component, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,6-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol,
2,2,4-trimethyl-1,3-pentanediol,
1,4-bis (2-hydroxymethyl) cyclohexane, 2,2-bis (4-hydroxypropoxyphenyl) propane, bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, etc., and polybasic acids The components are maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, 1,
Unsaturated carboxylic acids such as 2,4-benzenetricarboxylic acid and 1,2,5-benzenetricarboxylic acid, phthalic acid, terephthalic acid, isophthalic acid, succinic acid, adipic acid, malonic acid, sebacic acid, 1,2,4 -Cyclohexanetricarboxylic acid, 1,2,5-cyclohexanetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,3
Saturated carboxylic acids such as -dicarboxy-2-methyl-2-methylcarboxypropane and tetra (methylcarboxy) methane; and their anhydrides and esters with lower alcohols. Examples include maleic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, tetrachlorophthalic anhydride, tetrachlorophthalic anhydride, tetrabromophthalic anhydride, dimethyl terephthalate, etc. be able to. The above-mentioned polyol component and polybasic acid component may be combined one by one, or may be polymerized by combining multiple types.

As the colorant used in the toner for developing electrostatic charge of the present invention, any of dyes and pigments known to those skilled in the art can be used, regardless of whether they are organic or inorganic. Specific examples thereof include, for example, carbon black, nigrosine dye, aniline blue, calco oil blue, chrome yellow, ultramarine blue,
Dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachide green oxalate, lamp black, oil black,
Examples thereof include azo oil black and rose bengal. If necessary, two or more of these may be used in combination.

The magnetic powder used for obtaining the magnetic toner includes, for example, powders of ferromagnetic metals such as iron, cobalt, and nickel, magnetite, hematite, and the like.
A powder of a metal compound such as ferrite is exemplified. Since these magnetic powders also function as colorants, they may be used alone, but may be used in combination with the above-described colorants.

The amount of the colorant and / or the magnetic powder to be added can be in a wide range depending on the type of the colorant and / or the magnetic powder to be used and the type of the toner for developing electrostatic charge to be obtained. , Preferably 1 to 70 in the toner composition.
%, More preferably 1 to 60% by weight.

In the toner for electrostatic charge development of the present invention,
Further, if necessary, a conventionally well-known toner additive such as a charge controlling agent, a fluidizing agent, and waxes can be added to the inside or the outer surface of the toner particles.

Examples of the charge controlling agent include nigrosine, monoazo dye, zinc, hexadecyl succinate,
Alkyl esters or alkylamides of naphthoic acid,
Examples thereof include nitrohumic acid, N, N-tetramethyldiaminebenzophenone, N, N-tetramethylbenzidine, triazine, and salicylic acid metal complex.

[0026] Examples of the fluidizing agent include silica, aluminum oxide, titanium oxide and magnesium fluoride.

As the waxes, the cyclic method softening point is 80 to 80.
180 ° C. polymers, high melting point paraffin wax having a melting point of 60 to 70 ° C., fatty acid esters, partially saponified products thereof, higher fatty acids, fatty acid metals, higher alcohols, etc., among which polyethylene, polypropylene And the like are preferred. However, when such waxes are added to the toner for electrostatic charge development of the present invention, if the amount of addition is large, the fluidity of the toner, characteristics such as rising of charging are likely to be greatly impaired. The amount added is preferably 100% by weight or less, more preferably 50% by weight or less, based on the amount of the crystalline acrylate polymer and / or the crystalline methacrylate polymer blended in the toner. desirable.

The toner for electrostatic charge development comprising the composition according to the present invention comprises the above-mentioned crystalline acrylate-based polymer and / or crystalline methacrylate-based polymer, and a binder resin, a colorant and / or Alternatively, it can be obtained by melt-kneading together with a magnetic powder and other additives such as a charge control agent incorporated into the toner particles as necessary, cooling, pulverizing, and classifying. The melting and kneading temperature for obtaining the electrostatic charge developing toner having the composition according to the present invention by such a pulverization method varies depending on the type of the binder resin used, but is, for example, 100 to 200 ° C. Preferably 120
The temperature is suitably about 180 ° C., and can be carried out using various kneaders, extruders and the like. Also, pulverization can be performed using a known pulverizer such as a cutter mill or a jet mill. By classification, the average particle diameter of the toner is, for example, 3 to 15 μm, preferably 5 to 1 μm.
It is about 2 μm. The toner obtained by such a pulverization method may be subjected to a sphering treatment by performing a heating treatment or the like. Finally, the toner particles thus obtained are subjected, if necessary, to a process of attaching an additive such as a fluidizing agent to the surface of the toner particles.

[0029]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited to the following examples. The “parts” in the following Examples and Comparative Examples are all by weight unless otherwise specified.

Example 1 100 parts of styrene / n-butyl acrylate copolymer (Tg = 65 ° C., Mw = 160000, Mn = 5300) Stearyl polyacrylate 3 parts (melting point (DSC peak temperature) 53.8 ° C.) Mw = 114000, Mn = 5600, melt viscosity (140 ° C., 532 cP) Carbon black 10 parts (MA-600, manufactured by Mitsubishi Kasei Kogyo Co., Ltd.) Spiron black TRH 3 parts (Hodogaya Chemical Industry Co., Ltd.) The above mixture Was kneaded at 140 ° C. for 15 minutes by a Labo Plast mill, crushed to a size of 1 mm or less, further finely crushed by a jet mill, and then classified by an air classifier to obtain an average particle size of 7.
A 5 μm raw toner powder (1) for electrostatic charge development was obtained.

This electrostatic charge developing toner raw powder (1) 100
0.3 parts by weight of hydrophobic Aerosil R972 (manufactured by Nippon Aerosil Co., Ltd.) was added to the parts by weight and uniformly dispersed to obtain a toner (1) for electrostatic charge development.

As a result of performing an image output test on the electrostatic charge developing toner (1) using a commercially available copying machine Leodry 7610 (manufactured by Toshiba Corporation), a stable and good image was obtained without any offset phenomenon. Obtained.

The dispersion state of stearyl polyacrylate in the toner (1) for electrostatic charge development was evaluated by a transmission electron microscope (T
EM) It was confirmed by the photograph that it was very fine
It was confirmed that domains having a size of m or less were formed and were uniformly dispersed in the toner particles.

Example 2 100 parts of styrene / n-butyl acrylate copolymer (Tg = 63 ° C., Mw = 200000, Mn = 7500) Stearyl polymethacrylate 5 parts (melting point (peak temperature by DSC method) 37.8 ° C.) Mw = 256000, Mn = 19900, melt viscosity (140 ° C.) 6800 cP) Mapico BL-200 60 parts (manufactured by Titanium Industry Co., Ltd.) Bontron E-82 3 parts (manufactured by Orient Chemical Industry Co., Ltd.) After kneading with a mill at 135 ° C. for 15 minutes, the mixture was coarsely crushed to 1 mm or less, further finely crushed by a jet mill, and classified by an air classifier to obtain an average particle diameter of 1 mm.
A 0.5 μm raw toner powder (2) for electrostatic charge development was obtained.

The toner powder for electrostatic charge development (2) 100
To 0.4 parts by weight of hydrophobic Aerosil R972 (manufactured by Nippon Aerosil Co., Ltd.) was added and uniformly dispersed to obtain a toner for electrostatic charge development (2).

The toner (2) for electrostatic charge development was subjected to an image output test using a commercially available copying machine HP-5000 (manufactured by Canon Inc.). As a result, a stable and good image was obtained without any offset phenomenon. was gotten.

When the dispersion state of poly (stearyl methacrylate) in the toner (2) for electrostatic charge development was confirmed by a TEM photograph, very fine domains having a size of about 1.0 μm or less were formed, and It was confirmed that the particles were uniformly dispersed in the inside.

Comparative Example 1 Styrene / n-butyl acrylate copolymer 100 parts (Tg = 65 ° C., Mw = 160000, Mn = 5300) Carbon black 10 parts (MA-600, manufactured by Mitsubishi Kasei Kogyo Co., Ltd.) 3 parts of black TRH (manufactured by Hodogaya Chemical Industry Co., Ltd.) The above mixture was kneaded in the same manner as in Example 1, and further crushed and classified. . Thereby, the average particle size is 7.8 μm.
m of the comparative toner powder for electrostatic charge development (a) was obtained. Hydrophobic Aerosil R972 (manufactured by Nippon Aerosil Co., Ltd.) was added to 100 parts by weight of this comparative toner powder for electrostatic charge development (a).
Three parts were added and uniformly dispersed to obtain a comparative toner (a) for electrostatic charge development.

This comparative electrostatic charge developing toner (a) was subjected to an image output test using a commercially available copying machine Leodry 7610 (manufactured by Toshiba Corporation). No image could be obtained.

Comparative Example 2 An average particle diameter of 7.6 μm was obtained in the same manner as in Comparative Example 1 except that 5 parts of a low molecular weight polypropylene wax (Viscol 660P, manufactured by Sanyo Chemical Industries, Ltd.) was added to the composition of Comparative Example 1. (B) was obtained.

This comparative toner powder for electrostatic charge development (b)
To 100 parts by weight, 0.3 parts of hydrophobic Aerosil R972 (manufactured by Nippon Aerosil Co., Ltd.) was added and uniformly dispersed to obtain a comparative electrostatic charge developing toner (b).

The comparative electrostatic charge developing toner (a) was subjected to an image output test using a commercially available copying machine Leodry 7610 (manufactured by Toshiba Corporation). As a result, no offset phenomenon was observed, but the image density was stable. Without this, good images could not be obtained continuously.

When the dispersion state of the wax in the comparative electrostatic charge developing toner (b) was confirmed by a TEM photograph, the wax domain was large and the dispersion was insufficient.

[0044]

As described above, the toner composition of the present invention has a melting point considerably lower than that of a conventionally used polyolefin wax, a relatively high melt viscosity, and a weight average molecular weight of 35,000 to 500,000 . And melting
A crystalline acrylate polymer and / or a crystalline methacrylate polymer having a viscosity of 100 cP or more at 140 ° C. is blended in an amount of 0.5 to 30% by weight, and Since the dispersibility of the crystalline polymer is good, the polymer has good offset resistance, good fluidity, storage stability, and charging characteristics.

 ────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-2-5071 (JP, A) JP-A-4-57062 (JP, A) JP-A-4-240660 (JP, A) JP-A-3-3 61953 (JP, A) JP-A-4-51156 (JP, A)

Claims (1)

(57) [Claims] To 1. A toner composition containing at least a toner binder resin and a colorant, the weight average molecular weight of 350
100 to 500,000 and a melt viscosity of 10 at 140 ° C.
A toner composition comprising 0.5 to 30% by weight of a crystalline acrylate polymer and / or a crystalline methacrylate polymer having 0 cP or more .