JP2008076759A - Release agent master batch for toner, electrophotographic toner and method for manufacturing the toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a release agent master batch for toner, which is excellent in offset resistance and storage stability, and prevents filming on a photoreceptor, and does not cause problems of sticking / melt sticking on a doctor blade and solidification or aggregation of toner particles, and to provide an electrophotographic toner using the above release agent master batch, and a method for manufacturing the toner. <P>SOLUTION: The master batch contains a nonionic surfactant of 1 to 10 mass%, a resin and a release agent of 25 mass% or less. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a release agent master batch for toner, a pulverized toner using the release agent master batch, and a method for producing the same.

  In an electrophotographic apparatus, a recording material to which a toner image is transferred is generally fixed by a heat roll type fixing device using heat and pressure. In such a fixing method, a part of the toner image on the recording material may adhere to the roller, and a so-called offset phenomenon may occur in which the recording material becomes soiled when the next toner image is fixed. In order to prevent such an offset phenomenon, there is a method of applying oil to the roller of the fixing device.

  However, it is possible to prevent the offset phenomenon by applying oil to the roller of the fixing device, but an oil film is formed on the image surface, and it is impossible to write on the image, or the surface is sticky. In addition, there is a problem that an application device for applying oil is necessary, and recently, oilless fixing without using oil has been demanded.

  On the other hand, the toner is also required to have low-temperature fixability and durability.

  As a method for satisfying such a requirement, there is a method of including a release agent in the toner. In order to achieve all of improvement in offset resistance, low-temperature fixing, high durability, and oil-less fixing device. Therefore, it is necessary to add a large amount of release agent. However, since the release agent is difficult to mix with the binder resin such as polyester resin constituting the toner, it cannot be uniformly dispersed in the binder resin, and it is difficult to add a large amount of the release agent. . Therefore, a release agent masterbatch is prepared by previously kneading a low molecular weight resin such as petroleum resin, which is easily mixed with the release agent, and a release agent. Thus, it has been proposed to produce toner (see, for example, Patent Documents 1 and 2).

  However, since the low molecular weight resin is difficult to mix with the polyester resin, when such a release agent master batch is kneaded with the binder resin and the colorant, the low molecular weight resin forms a sea-island structure in the polyester resin. When the sea-island structure is formed, the low molecular weight resin becomes a pulverized toner pulverization interface, and the low molecular weight resin and the release agent dispersed in the low molecular weight resin are exposed on the surface of the toner particles. As a result, the toner particles are fixed / fused to the doctor blade, the toner particles are solidified or aggregated, and filming to the photosensitive member occurs, resulting in problems such as storage stability.

In addition, as these low molecular weight resins are used in hot melt adhesives, there is also a problem that hot offset is likely to occur because of their high adhesive strength.
JP 2004-295046 A JP 2005-17593 A

  The present invention is made under such circumstances, and is excellent in anti-offset property and filming storage stability to a photoconductor, causing sticking / fusion to a doctor blade, and causing solidification and aggregation of toners. It is an object of the present invention to provide a toner release agent masterbatch that does not occur, an electrophotographic toner using such a release agent masterbatch, and a method for producing the same.

  In order to solve the above-mentioned problem, the first aspect of the present invention includes 1% by mass or more and 10% by mass or less of a nonionic surfactant, a resin, and 25% by mass or less of a release agent. A toner release agent master batch is provided.

  In such a release agent master batch for toner, it is preferable to use polyoxyethylene alkyl ether or polyoxyethylene fatty acid ester as the nonionic surfactant. Moreover, it is preferable to use a polyester resin as resin. Moreover, it is preferable to use carnauba wax as a release agent.

  According to a second aspect of the present invention, there is provided an electrophotographic toner obtained by pulverizing a resin kneaded product containing the release agent master batch, the binder resin, and the colorant.

  The third aspect of the present invention includes a step of melt kneading the release agent master batch, the binder resin, and the colorant described above, a step of cooling and pulverizing the kneaded product, and a step of classifying the pulverized product. The present invention provides a method for producing an electrophotographic toner.

  According to the present invention, by adding a predetermined amount of a nonionic surfactant, the nonionic surfactant functions as a compatibilizer between the release agent and the resin during kneading, and the release agent is uniformly in the resin. A dispersed toner release agent master batch is obtained. The toner obtained using this release agent masterbatch is excellent in anti-offset property and filming storage stability to the photoreceptor, causes sticking / fusion to the doctor blade, and solidifies or aggregates between the toners. Will not occur.

  The best mode for carrying out the invention will be described below with reference to the drawings.

  The toner release agent masterbatch according to the first embodiment of the present invention includes 1 to 10% by mass of a nonionic surfactant, a resin, and a release agent of 25% by mass or less. To do.

  Nonionic surfactants include polyoxyalkylene alkyl ethers such as polyoxyethylene alkyl ether, polyoxyethylene derivatives, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerin fatty acid esters, polyoxy Examples include ethylene fatty acid ester, polyoxyethylene hydrogenated castor oil, polyoxyethylene alkylamine, and alkyl alkanolamide.

  Among these, the use of polyoxyethylene alkyl ether and polyoxyethylene derivatives can give good dispersion in the binder resin, and does not contain environmental hormones such as nonylphenol and octylphenol. Particularly preferred.

  The nonionic surfactant functions as a compatibilizer between the release agent and the polyester resin during kneading. Since the nonionic surfactant is nonionic and does not ionize, even if it remains in the toner, the chargeability of the toner is not adversely affected. Further, the durability is not lowered.

  The resin is preferably a resin used for a toner binder. Examples of such a resin include a polyester resin, a styrene acrylic resin, and an epoxy resin. In these, a polyester resin is preferable.

A conventionally known release agent can be used as the release agent. Examples of such a release agent include those having low polarity such as low molecular weight polyethylene, low molecular weight polypropylene, and paraffin, and those having high polarity such as carnauba wax and ester. In addition, the emulsion type carboxyl group-modified polyolefin is modified so as to have a carboxyl group with an olefin unit such as ethylene, propylene, butene-1, and pentene-1 as a skeleton, and at least a part of the carboxyl group is formed with ammonia or amine. It is also possible to use neutralized polyethylene wax, polypropylene wax or the like. Of these waxes, carnauba wax is preferred.
In the release agent master batch containing the above components, the blending amount of the release agent needs to be 25% by mass or less. If the compounding amount of the release agent exceeds 25% by mass, it will hinder the raw material mixing step and the kneading step, making it difficult to produce the toner.

  Moreover, the compounding quantity of nonionic surfactant needs to be 1 mass% or more and 10 mass% or less. If the blending amount of the nonionic surfactant is less than 1% by mass, the effect of the present invention cannot be obtained, and if it exceeds 10% by mass, the raw material mixing process and the kneading process are hindered, and it is difficult to manufacture the toner. Become.

  The release agent master batch for toner according to the first embodiment of the present invention can be obtained by mixing the components described above, melt-kneading, stretching, and pulverizing.

  The pulverized toner according to the second embodiment of the present invention is manufactured in the following manner using the toner release agent master batch obtained as described above.

  First, a toner raw material including a release agent master batch, a binder resin, and a colorant is mixed by a mixer. As a mixing machine, arbitrary things, such as a Henschel mixer, a super mixer, a V-type blender, and a Nauta mixer, can be used.

  The raw material mixture is then fed to a kneader where it is melt kneaded. As the kneading machine, any type of extrusion kneading machine such as a twin-screw extrusion kneading machine and a single-screw extrusion kneading machine, an open roll type kneading machine such as a continuous two-roll mill, a continuous three-roll mill, and a batch roll mill can be used. Things can be used.

  The melt-kneaded product from the kneader is usually cooled, pulverized, and classified to a predetermined particle size according to the method used for producing the toner to obtain a toner particle matrix. The cooling means, the pulverizing means, and the classification means are not particularly limited, and those usually used for toner production can be employed. For example, a cooling means by rolling or blowing an air flow can be used for cooling, and an airflow pulverizer such as a collision plate pulverizer can be used for pulverization, and various airflow classifiers can be used for classification. Can be used.

  An external additive such as silica is added to the toner particle matrix thus obtained, and mixed and stirred to obtain a pulverized toner.

  The pulverized toner according to the second embodiment of the present invention described above can contain a charge control agent in addition to the binder resin, the colorant, the release agent, and the external additive. As the charge control agent, any of those usually used for electrophotographic toners can be used.

  As described above, the pulverized toner according to the second embodiment of the present invention can contain a large amount of release agent by using a predetermined release agent master batch. Conventionally, there has been a proposal to incorporate a large amount of a release agent by using a release agent masterbatch containing a low molecular weight resin. However, a release agent dispersed in a low molecular weight resin or a low molecular weight resin is used as a toner particle. Various problems were caused such as exposure to the surface, adhesion / fusion of toner particles to a doctor blade, solidification and aggregation of toner particles, filming on a photoreceptor, and low storage stability. In the present invention, such a problem is solved by blending a nonionic surfactant to form a release agent master batch.

  That is, since it is difficult to mix the release agent and the polyester resin, it is difficult to form a release agent master batch. However, by adding a nonionic surfactant to the release agent and the polyester resin, The activator acts as a compatibilizer between the release agent and the polyester resin, and it becomes possible to form a release agent masterbatch. When the binder resin and the masterbatch are kneaded, a homogeneous kneaded product is obtained. As a result, toner particles in which the release agent is uniformly dispersed at a high concentration can be obtained.

  Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples.

Example A nonionic surfactant, a polyester resin, and a release agent having the composition shown in Table 1 below were mixed using a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.), and then melt-kneaded using a twin-screw extruder. The obtained kneaded product was cooled and stretched, and pulverized to a particle size of 2 mm or less with a feather mill (manufactured by Hosokawa Micron Corporation) to obtain release agent master batches of Examples 1 to 8.

  30 parts by mass of each of the obtained release agent master batches of Examples 1 to 8, 65 parts by mass of binder resin, 4 parts by mass of colorant (ECR-101: Dainichi Seika Kogyo Co., Ltd.), and charge control agent 1 part by mass (LR147: Nippon Carlit Co., Ltd.) was thoroughly mixed with a Henschel mixer, melted and kneaded with a twin screw extruder, cooled, and a collision plate crusher “Disversion Separator” (Nippon Pneumatic Industry Co., Ltd.) ), And then a classification step to obtain a powder having a weight average particle size of 9.0 μm. To 100 parts by mass of the obtained powder, 1.5 parts by mass of hydrophobic silica “RX200” (manufactured by Nippon Aerosil Co., Ltd.) is added as an external additive, and 180 seconds at 3200 r / min with a 10 liter Henschel mixer. The powder was subjected to a surface treatment by stirring to obtain magenta toners of Examples 1 to 8.

  Similarly, master batches of Comparative Examples 1 to 8 were obtained in the same manner as in Examples 1 to 8, using a nonionic surfactant, a polyester resin, and a release agent having the composition shown in Table 1 below. It was.

  Moreover, the magenta toner of Comparative Examples 1-8 was obtained like Example 1-8 using the obtained masterbatch.

  Next, the magenta toners of Examples 1 to 8 and Comparative Examples 1 to 8 manufactured as described above were mounted on “Page Presto N5” (manufactured by Casio Computer Co., Ltd.) from which the oil application unit was removed. Printing was performed, and white streaks due to fixation / fusion to the doctor blade, white streaks due to aggregation of toner, hot offset, drum filming, and storage stability were evaluated. The results are also shown in Table 1 below.

  The evaluation criteria are as follows.

1. White streaks due to fixation / fusion to the doctor blade ○: No white streaks ×: With white streaks 2. White streaks due to toner aggregation ○: No white streaks ×: White streaks Hot offset ○: No hot offset ×: Hot offset Drum filming ○: No drum filming △: Drum filming slightly present ×: Drum filming present 5. Storage stability Storage stability after storage for 1 week in an atmosphere of temperature 50 ° C. and humidity 90% was evaluated.

○: Good ×: Bad

  From Table 1 above, the toners of Examples 1 to 8 manufactured using a release agent masterbatch containing 1 to 10% by weight of a nonionic surfactant, a polyester resin, and a release agent of 25% by weight or less. It can be seen that all are excellent in durability / offset property / drum filming / storage stability.

  On the other hand, the toner according to Comparative Example 1 obtained by using a release agent master batch containing only a polyester resin and a release agent without containing a nonionic surfactant was originally a polyester resin and a release agent. Therefore, it is difficult to disperse the release agent in the master batch and in the toner. As a result, the toner is fixed / fused to the doctor blade, the toner is solidified or aggregated, and the photosensitivity. Filming on the body has occurred and storage stability has deteriorated.

  Further, the toners of Comparative Examples 2 to 5 and 8 in which the blend amount of the nonionic surfactant exceeded 10% by mass caused trouble in the mixing step and the kneading step, and it was difficult to produce the toner. Similarly, in the toners of Comparative Examples 6 to 8 in which the compounding amount of the release agent exceeds 25% by mass, the mixing process and the kneading process are hindered, making it difficult to manufacture the toner.

  In Examples 1 to 8, only one type of release agent was used, but two or more types of release agents may be used. In Examples 1 to 8, only one type of nonionic surfactant was used, but two or more types of nonionic surfactant may be used.

  Furthermore, in Examples 1-8, although the mold release agent masterbatch was manufactured with the biaxial extrusion kneader, you may manufacture with a batch type pressure kneader or a Banbury mixer. In Examples 1 to 8, the toner is formed using a twin-screw extrusion kneader, but the toner may be formed using a continuous roll mill.

  Furthermore, in Examples 1 to 8, the toner using the polyester resin as the binder resin has been described, but the toner using the styrene acrylic resin as the binder resin and the toner using the epoxy resin are similarly described. A release agent master batch can be obtained by adding a nonionic surfactant to the resin and the release agent.

Claims (6)

  A release agent master batch for toner, comprising 1% by mass or more and 10% by mass or less of a nonionic surfactant, a resin, and 25% by mass or less of a release agent.   The toner release agent masterbatch according to claim 1, wherein the nonionic surfactant is polyoxyethylene alkyl ether or polyoxyethylene fatty acid ester.   The toner release agent masterbatch according to claim 1, wherein the resin is a polyester resin.   The toner release agent masterbatch according to claim 1, wherein the release agent is carnauba wax.   An electrophotographic toner obtained by pulverizing a resin kneaded material containing the release agent masterbatch according to claim 1, a binder resin, and a colorant. A step of melt-kneading the release agent masterbatch according to any one of claims 1 to 4, a binder resin, and a colorant,
A method for producing an electrophotographic toner comprising: cooling and pulverizing the kneaded product; and classifying the pulverized product.