JP2007199207A - Styrene-acrylic resin for grinded toner and grinded toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a styrene-acrylic resin for toner having high grinding efficiency, and to obtain a toner excellent in balance of low-temperature fixability and anti-offset properties. <P>SOLUTION: The styrene-acrylic resin for grinded toner contains a tetrahydrofuran (THF)-insoluble component and has a jet mill grinding efficiency of ≥70 mass%. In addition, the styrene-acrylic resin for pulverized toner is obtained by polymerizing monomers including a styrene monomer (a), a monofunctional (meth)acrylic monomer (b) and trimethylolpropane tri(meth)acrylate (c), wherein a mass average molecular weight of a tetrahydrofuran (THF)-soluble component by gel permeation chromatography (GPC) is 50,000-500,000, and the styrene-acrylic resin for pulverized toner contains a tetrahydrofuran (THF)-insoluble component and has a jet mill pulverization efficiency of ≥70%. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pulverized toner used for developing an electrostatic charge image or a magnetic latent image in an electrophotographic method, an electrostatic recording method, an electrostatic printing method, and the like, and a styrene-acrylic resin used as a binder resin for the pulverized toner. Is.

The image forming process by the electrophotographic method and the electrostatic printing method includes the following three steps.
(1) The photoconductive insulating layer is uniformly charged, the insulating layer is exposed, and an electric latent image is formed by dissipating the charge on the exposed portion. Development process to visualize by attaching a fine powder toner
(2) a transfer step of transferring the obtained visible image onto a transfer material such as transfer paper;
(3) A fixing step for permanent fixing by heating or pressing.

As a toner used in such an electrophotographic method or electrostatic printing method, various performances are required in each of the above steps. For example, in copiers and printers, blocking resistance that prevents toner from blocking during storage is required, toner charging stability in the development process, and molten toner adheres to the heat roller in the fixing process using the heat roller fixing method. Non-offset property and fixing property of toner to paper are required.
In recent years, energy saving, high speed, and high image quality of copiers and printers have progressed, and for toners, there is a strong demand for toners that are particularly excellent in the balance between non-offset properties and low-temperature fixability and fine in particle size.

Conventionally, the toner is obtained by a pulverization method and a chemical method. The toner obtained by the chemical method can obtain a high-quality image with a fine particle size, but it is difficult to perform advanced molecular design. Poor balance between offset and low-temperature fixability. Further, since the manufacturing process and equipment are complicated, the toner obtained by the chemical method is expensive and not practical.
On the other hand, the toner obtained from the pulverized toner can be designed with a high molecular weight and can achieve both non-offset property and low-temperature fixability. However, in order to improve the image quality, in order to obtain a fine particle size toner Consumes a lot of energy and time. In order to solve this problem, a technique using a resin internally added with a foaming agent (for example, see Patent Document 1) or an attempt to improve toner pulverization property by adding a brittle resin (for example, Patent Documents 2 to 2). 3), but there is a drawback that the durability of the toner is lowered. Further, attempts have been made to improve the pulverization property by adjusting the molecular weight distribution of the binder resin for toner, but there is a drawback that the balance between the fixing property and the high temperature offset resistance is lowered.
JP-A-4-257868 JP 2000-19775 A JP-A-11-65161

  An object of the present invention is to provide a styrene-acrylic resin for pulverized toner and a pulverized toner, which are styrene-acrylic resin for toner having a high pulverizing efficiency and can obtain a toner having a good balance between low-temperature fixability and non-offset property. There is.

  The present invention relates to a styrene-acrylic resin for pulverized toner containing a tetrahydrofuran (THF) insoluble component and having a jet mill pulverization efficiency of 70% by mass or more. Further, the styrene monomer (a), monofunctional ( A styrene-acrylic resin for pulverized toner obtained by polymerizing a monomer containing a (meth) acrylic monomer (b) and trimethylolpropane tri (meth) acrylate (c), the gel permeation chromatography For pulverized toner having a mass average molecular weight of 50,000 to 500,000 in tetrahydrofuran (THF) solubles by GRAPHY (GPC), including tetrahydrofuran (THF) insolubles, and jet mill pulverization efficiency of 70% by mass or more It relates to a styrene-acrylic resin.

  According to the present invention, it is possible to obtain a styrene-acrylic resin for pulverized toner and a pulverized toner that can obtain a styrene-acrylic resin for toner having high pulverization efficiency and a toner having a good balance between low-temperature fixability and non-offset property.

The styrene-acrylic resin for pulverized toner of the present invention contains an insoluble content of tetrahydrofuran (hereinafter abbreviated as THF) and has a jet mill pulverization efficiency of 70% by mass or more.
The THF-insoluble matter is a styrene-acrylic resin dissolved in THF at 70 ° C. under reflux for 3 hours, and the solution is suction filtered using a glass filter previously filled with Celite (No. 545), and remains after suction filtration. It is a value (mass fraction) obtained by dividing the resin mass by the dissolved resin mass.

  The THF-insoluble content is not particularly limited, but is preferably 0.1 to 60% by mass. When the THF-insoluble content is 0.1% by mass or more, high-temperature offset resistance tends to be improved, and when it is 60% by mass or less, fixability tends to be improved. The lower limit of the THF-insoluble content is more preferably 3% by mass or more, and particularly preferably 5% by mass or more. The upper limit of the THF-insoluble content is more preferably 50% by mass or less, and particularly preferably 35% by mass or less.

  Jet mill pulverization efficiency means that a kneaded resin that has passed 1 mm mesh in one minute under the condition that the average particle size of the finely pulverized product obtained is 7 μm using a laboratory jet mill manufactured by Hosokawa Micron. This is the mass yield of finely pulverized resin obtained when 15 g is continuously supplied for 30 minutes. The kneaded resin is a resin obtained by using a biaxial extruder PCM-29 manufactured by Ikegai Co., Ltd., setting a cylinder temperature of 120 ° C., a feed amount of 70 g per minute, and a residence time of 90 seconds.

  The styrene-acrylic resin for pulverized toner of the present invention is not particularly limited. For example, a monomer containing a styrene monomer (a) and a monofunctional (meth) acrylic monomer (b) is polymerized. Resin obtained in this way. Note that “(meth) acryl” means “methacryl” or “acryl”.

  The styrenic monomer (a) is not particularly limited. For example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p- n-butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-tensyl styrene, pn-dodecyl styrene, p-phenyl styrene, 3 Examples thereof include 4-dicyclosylstyrene, and among them, styrene is preferable. These styrenic monomers can be used alone or in combination of two or more.

  The content of the structural unit derived from the styrenic monomer (a) is not particularly limited, but it is preferably 50% by mass or more in the total amount of the styrene-acrylic resin. When this content is 50% by mass or more, the fixability tends to be good. Further, the lower limit of the content is more preferably 60% by mass or more, and particularly preferably 70% by mass or more.

  The monofunctional (meth) acrylic monomer (b) is not particularly limited, and examples thereof include ethyl acrylate, methyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, and 2-ethylhexyl acrylate. , Stearyl acrylate, methacrylic acid, ethyl methacrylate, methyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, propyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, etc. It is done.

  The content of the structural unit derived from the monofunctional (meth) acrylic monomer (b) is not particularly limited, but is preferably in the range of 5 to 50% by mass based on the total amount of the styrene-acrylic resin. When this content is 5% by mass or more, the fixability tends to be improved, and when it is 50% by mass or less, the preservability tends to be improved. Further, the lower limit of the content is more preferably 10% by mass or more, and particularly preferably 15% by mass or more. The upper limit is more preferably 40% by mass or less, and particularly preferably 30% by mass.

  As a styrene-acrylic resin, you may contain the structural unit induced | guided | derived from a polyfunctional vinyl monomer other than said component (a) and component (b). The polyfunctional vinyl monomer is not particularly limited as long as it is a compound having two or more ethylenically unsaturated groups in one molecule. For example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene di (meth) acrylate Glycol, di (meth) acrylic acid dipropylene glycol, di (meth) acrylic acid 1,3-butylene glycol, bisphenol A derivative di (meth) acrylic acid, trimethylolpropane di (meth) acrylate, trimethylolpropane tri ( And (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, and dipentaerythritol tetra (meth) acrylate. These polyfunctional compounds are used alone or in combination of two or more.

Among polyfunctional vinyl monomers, trimethylolpropane tri (meth) acrylate (c) is particularly preferable.
The content of the structural unit derived from trimethylolpropane tri (meth) acrylate (c) is not particularly limited, but is preferably 0.05 to 3% by mass in the total amount of the styrene-acrylic resin. When this content is 0.05% by mass or more, high-temperature offset resistance tends to be improved, and when it is 3% by mass or less, low-temperature fixability tends to be improved. The lower limit is more preferably 0.1% by mass or more, and particularly preferably 0.3% by mass or more. The upper limit is more preferably 2% by mass or less, and particularly preferably 1% by mass or less.

  The styrene-acrylic resin may contain a constituent unit derived from another vinyl monomer in addition to the constituent unit derived from the polyfunctional vinyl monomer. Other vinyl monomers are not particularly limited, but examples thereof include unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, and cinnamic acid, unsaturated dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid, and maleic acid. Examples thereof include carboxyl group-containing vinyl monomers such as unsaturated monocarboxylic acid monoesters such as monomethyl, monoethyl maleate, monobutyl maleate, monomethyl fumarate, monoethyl fumarate and monobutyl fumarate.

  The styrene-acrylic resin for pulverized toner of the present invention contains, among others, a styrene monomer (a), a monofunctional (meth) acrylic monomer (b), and trimethylolpropane tri (meth) acrylate (c). A resin obtained by polymerizing monomers is preferred.

  Further, the number average molecular weight by GPC of the THF-soluble component of the styrene-acrylic resin for pulverized toner of the present invention is not particularly limited, but is preferably 50,000 to 500,000. When the number average molecular weight is 50,000 or more, the anti-offset region tends to be good, and when it is 500,000 or less, the fixability tends to be good. The lower limit of the number average molecular weight is more preferably 80,000 or more, and particularly preferably 100,000 or more. The upper limit of the number average molecular weight is more preferably 400,000 or less, and particularly preferably 300,000 or less.

The GPC analysis of the THF soluble content was obtained by filtering a THF solution in which 0.4% by mass of styrene-acrylic resin for pulverized toner was dissolved with a PTFE membrane (Mishori Disc H-25-5 manufactured by Tosoh Corporation). The column was composed of three TSKgel / GMH _XL columns (manufactured by Tosoh Corporation).

  The molecular weight peak value of the THF-soluble component is not particularly limited, but is preferably 3,000 to 40,000. When the molecular weight peak value is 3,000 or more, the durability tends to be good, and when it is 40,000 or less, the fixability tends to be good. The lower limit of the molecular weight peak value is more preferably 5,000 or more, and particularly preferably 7,000 or more. The upper limit of the molecular weight peak value is more preferably 35,000 or less, and particularly preferably 30,000 or less.

The method for producing the styrene-acrylic resin for pulverized toner of the present invention is not particularly limited, and can be produced by, for example, an emulsion polymerization method, a suspension polymerization method, a bulk polymerization method, a solution polymerization method, etc. Although it can be produced by mixing resins produced by various polymerization methods, it is preferably obtained only by suspension polymerization. This is because the resin obtained by suspension polymerization is excellent in high temperature offset resistance and it is easy to reduce the amount of solvent and monomer remaining in the resin.
The production time of the styrene-acrylic resin for pulverized toner obtained by suspension polymerization is preferably 10 hours or less, more preferably 8 hours or less, and particularly preferably 6 hours or less.

In order to achieve both the production time of the styrene-acrylic resin for pulverized toner and a small residual monomer amount, it is preferable to use two or more polymerization initiators having different half-life temperatures in combination. In this case, the 10-hour half-life temperature difference between the polymerization main initiator that decomposes on the low temperature side and the subpolymerization initiator that decomposes on the high temperature side is preferably 10 ° C. or more. By using a polymerization initiator having a 10-hour half-life temperature difference of 10 ° C. or more in combination, it becomes possible to reduce the residual monomer in a short time. Preferably, the 10-hour half-life temperature difference is 15 ° C. or more. Preferably it is 20 degreeC or more.
Furthermore, the polymerization temperature is preferably set to a temperature higher by 10 ° C. or more than the one-hour half-life temperature of the secondary polymerization initiator, so that both the production time and a small amount of residual monomer can be achieved. It is more preferable to set the polymerization temperature to a temperature 20 ° C. or more higher than the 10-hour half-life temperature.

  The initiator used for suspension polymerization is not particularly limited as long as it is a radical polymerization initiator, and an organic peroxide or an azo initiator can be used. Among them, an organic peroxide is preferable because it has high initiator efficiency and does not generate a cyanide byproduct. The organic peroxide is not particularly limited. For example, octanonyl peroxide, lauroyl peroxide, stearyl peroxide, t-butylperoxy 2-ethylhexanoate, benzoyl peroxide, 1,1-bis (t -Butylperoxy) -3,3,5-trimethylcyclohexane, t-butylperoxylaurate and the like. Among these, from the point that the polymerization activity with respect to the monomer is sustained and the polymerization can be completed in a relatively short time, octanonyl peroxide, lauroyl peroxide, stearyl peroxide, t-butylperoxy 2-ethylhexanoate, t-hexylperoxy 2-ethylhexanoate, benzoyl peroxide, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, t-hexylperoxyisopropyl monocarbonate, t-butyl Peroxylaurate is preferred.

  Moreover, as a secondary initiator that decomposes on the high temperature side, t-hexyl peroxyisopropyl monocarbonate, t-butyl peroxylaurate, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy 2-ethylhexyl monocarbonate, Examples thereof include t-hexyl peroxybenzoate, t-butyl peroxyacetate, t-butyl peroxybenzoate, dicumyl peroxide, and di-t-butyl peroxide. Among them, from the viewpoint of initiator efficiency, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy 2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate, t-butyl peroxyacetate, t-butyl peroxybenzoate Di t-butyl peroxide is preferred.

  The Tg of the styrene-acrylic resin for pulverized toner of the present invention is not particularly limited, but is preferably 45 to 75 ° C. This is because the blocking resistance tends to decrease when the temperature is 45 ° C. or lower, and the fixability tends to decrease when the temperature is 75 ° C. or higher. The lower limit value of Tg is preferably 48 ° C. or higher, and more preferably 52 ° C. or higher. The upper limit value of Tg is preferably 70 ° C. or lower, and more preferably 65 ° C. or lower. Tg indicates a shoulder value in an endothermic curve of DSC measurement.

The softening temperature of the toner binder resin of the present invention is not particularly limited, but is preferably 90 to 175 ° C. This is because high temperature offset resistance tends to be improved when the temperature is 90 ° C. or higher, and fixability tends to be improved when the temperature is 175 ° C. or lower. The lower limit value of the softening temperature is more preferably 100 ° C. or higher, and even more preferably 110 ° C. or higher. The upper limit value of the softening temperature is more preferably 160 ° C. or less, and further preferably 145 ° C. or less.
The acid value of the binder resin for toner of the present invention is not particularly limited, but is preferably 30 mgKOH / g or less. This is because the moisture resistance tends to be improved at 30 mg KOH / g or less. The acid value is more preferably 20 mgKOH / g, still more preferably 15 mgKOH / g or less.

  Further, the amount of residual monomer in the toner binder resin of the present invention is not particularly limited, but is preferably 500 ppm or less. This is because when the concentration is 500 ppm or more, there is a tendency that the odor is less during printing. Preferably, it is 300 ppm or less, More preferably, it is the range of 100 ppm or less.

Next, the pulverized toner of the present invention will be described.
The pulverized toner of the present invention contains the styrenic binder resin described above. The content of the styrenic binder resin is not particularly limited, but is preferably 35 to 95 parts by mass in the total amount of toner. When this content is 35 parts by mass or more, fixability tends to be good, and when it is 95 parts by mass or less, offset resistance and color tone tend to be good. The lower limit of this content is more preferably 40 parts by mass or more, and the upper limit is more preferably 90 parts by mass or less.

  The pulverized toner of the present invention contains the above-mentioned styrenic binder resin composition, and if necessary, a colorant, a wax, a flow modifier, a charge control agent, a magnetic substance, and the like are added thereto. can do.

  As the colorant, commonly used carbon black, chromatic pigments and dyes can be used, and there is no particular limitation. In the case of color toner, for example, C.I. I. Solvent Yellow 21, C.I. I. Solvent Yellow 77, C.I. I. Solvent Yellow 114, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 83, C.I. I. Solvent Red 19, C.I. I. Solvent Red 49, C.I. I. Solvent Red 128, C.I. I. Pigment red 5, C.I. I. Pigment red 13, C.I. I. Pigment red 22, C.I. I. Pigment red 48.2, C.I. I. Disperse thread 11, C.I. I. Solvent Blue 25, C.I. I. Solvent Blue 94, C.I. I. Pigment blue 60, C.I. I. And CI Pigment Blue 15.3.

  The content of the colorant is not particularly limited, but is preferably in the range of 2 to 10 parts by mass in the total amount of toner from the viewpoint of toner color tone, image density, and thermal characteristics. The lower limit of this content is more preferably 3 parts by mass or more, and the upper limit is more preferably 8 parts by mass or less.

  A conventionally well-known thing can be used as a wax. For example, low molecular weight polyethylene wax, low molecular weight polyolefin wax such as low molecular weight polypropylene, synthetic hydrocarbon wax such as Fischer-Tropsch wax, natural wax such as beeswax, carnauba wax, candelilla wax, rice wax, montan wax, paraffin wax And petroleum waxes such as microcrystalline wax, higher fatty acids such as stearic acid, palmitic acid and myristic acid, metal salts of higher fatty acids, higher fatty acid amides, synthetic ester waxes, and various modified waxes. Of these waxes, carnauba wax and its modified wax and synthetic ester wax are preferably used. The reason for this is that carnauba wax and its modified wax and synthetic ester wax are finely dispersed moderately with respect to polyester resin and polyol resin, so that toner having excellent anti-offset property, transferability and durability as described later. This is because it is easy. These waxes can be used alone or in combination of two or more.

The fluidity improver is not particularly limited. For example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate strontium titanate, zinc oxide, silica sand, clay, mica, diatomaceous earth, Examples include cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride.
The content of the fluidity improver is not particularly limited, but is preferably in the range of 0.1 to 5 parts by mass with respect to 100 parts by mass of the toner. When the content of the fluidity improver is 0.1 parts by mass or more, filming tends to be suppressed, and when it is 5 parts by mass or less, the fixability tends to be good. The lower limit of this content is more preferably 0.2 parts by mass or more, and the upper limit is more preferably 3 parts by mass or less.

  Moreover, there is no restriction | limiting in particular as a charge control agent, The charge control agent conventionally used for electrophotography can be used. Examples of the negatively chargeable charge control agent include Bontron S-31, Bontron S-32, Bontron S-34, and Bontron S-36 manufactured by Orient Chemical Co., and Eisenspiron Black TVH manufactured by Hodogaya Chemical Co., Ltd. Metal-containing azo dyes; Quaternary ammonium salts such as Copy Charge NX VP434 manufactured by Hoechst; copper phthalocyanine dyes and the like. Examples of positively chargeable charge control agents include imidazole derivatives such as PLZ-2001 and PLZ-8001 manufactured by Shikoku Kasei; triphenylmethane derivatives such as Copy Charge BLUE PR manufactured by Hoechst; manufactured by Orient Chemical Co., Ltd. Bontron P-51, Copy Charge PXVP435 manufactured by Hoechst, quaternary ammonium salts such as cetyltrimethylammonium bromide, and polyamine resins such as AFP-B manufactured by Orient Chemical. In the present invention, one or more of the above charge control agents can be used. Moreover, it is also possible to use a main charge control agent and a charge control agent having a reverse polarity.

  The content of these charge control agents is not particularly limited, but is preferably in the range of 0.1 to 5 parts by mass based on the total amount of toner. When the content of the charge control agent is 0.1 parts by mass or more, the charge amount of the toner tends to be a sufficient level, and when it is 5 parts by mass or less, the decrease in the charge amount due to aggregation tends to be suppressed. .

The pulverized toner of the present invention can be used as any one of a magnetic one-component developer, a non-magnetic one-component developer, a magnetic two-component developer, and a non-magnetic two-component developer.
When the pulverized toner of the present invention is used as a magnetic one-component developer, the toner contains a magnetic substance. Examples of magnetic materials include ferromagnetic alloys including iron, cobalt, nickel and the like including ferrite and magnetite; so-called Heusler including manganese and copper such as manganese-copper-aluminum and manganese-copper-tin An alloy that does not contain a compound or a ferromagnetic element, such as an alloy, but exhibits ferromagnetism by appropriate heat treatment; chromium dioxide and the like.

  The content of these magnetic materials is not particularly limited, but is preferably in the range of 30 to 70 parts by mass in the total amount of toner. When the content of the magnetic material is 30 parts by mass or more, the charge amount of the toner tends to be a sufficient level, and when it is 70 parts by mass or less, the toner fixability tends to be good. The lower limit value of the content of the magnetic substance is more preferably 40 parts by mass or more, and the upper limit value is more preferably 60 parts by mass or less.

  When the pulverized toner of the present invention is used as a magnetic two-component developer or a non-magnetic two-component developer, it is used in combination with a carrier. As the carrier, a known material such as a magnetic substance such as iron powder, magnetite powder, or ferrite powder, a resin coating on the surface thereof, or a magnetic carrier can be used. As the coating resin for the resin coating carrier, generally known styrene resins, acrylic resins, styrene-acrylic copolymer resins, silicone resins, modified silicone resins, fluorine resins, and mixtures of these resins Etc. can be used. The amount of the carrier to be used in combination is not particularly limited, but when the amount is 900 parts by mass or more with respect to 100 parts by mass of the toner, the charge amount of the toner tends to be a sufficient level, which is preferable.

Next, the manufacturing method of the pulverized toner of the present invention will be described.
The production method of the pulverized toner of the present invention is not particularly limited, and can be produced using a known method. For example, a styrenic binder resin for toner described above and, if desired, a colorant, a flow modifier, a charge control agent, a magnetic material, and the like are mixed and then melt-kneaded with a twin screw extruder or the like, and coarsely pulverized, finely mixed. It can be manufactured by pulverizing and classifying and attaching inorganic particles to the toner surface as required. Further, in the above process, a treatment such as making the toner particles spherical after fine pulverization to classification may be performed.

Hereinafter, the present invention will be described in detail with reference to examples.
The THF insoluble matter, glass transition temperature (Tg), softening temperature, and GPC measurement were evaluated by the following methods.
(1) THF insoluble matter (mass%)
The sample was dissolved in THF at a temperature of 70 ° C. for 3 hours, and the solution was suction filtered using a glass filter previously filled with Celite (No. 545), and the insoluble matter was measured according to the following formula.
THF insoluble matter (mass%) = (C−B) / A × 100
Here, A represents the mass of the sample, B represents the mass of the dry glass filter (filled with celite) before the solution suction filtration, and C represents the mass of the dry glass filter (filled with celite) after filtration of the solution.

(2) Softening temperature (° C)
Using a flow tester CFT-500 manufactured by Shimadzu Corporation, nozzle: D = 1.0 mm, L = 10 mm, load 30 kgf, temperature rising rate 3 ° C./min. The temperature at which half the amount was extruded was defined as the softening temperature.
(3) Acid value (mgKOH / g)
It measured by the titration method using a KOH solution.
(4) Glass transition temperature (° C)
After the sample was heated to 100 ° C., it was shown as a shoulder value measured using DSC (manufactured by Seiko Denshi, DSC22 system) under a temperature increase rate of 10 / min.

(5) GPC measurement of THF soluble part The mass average molecular weight of THF soluble part was measured using GPC (the Tosoh Corporation make, HCL-8020). The sample used was a THF solution in which 0.4% by mass of resin was dissolved and filtered through a PTFE membrane (Mishori Disc H-25-5 manufactured by Tosoh Corporation), and the column was a TSKgel / GMH _XL column (Tosoh Corporation). (Made by company) The thing comprised from 3 was used. In addition, the calibration curve was obtained from F2000 / F700 / F288 / F128 / F80 / F40 / F20 / F2 / A1000 (standard polystyrene manufactured by Tosoh Corporation) and styrene monomer, and the molecular weight was determined in terms of polystyrene. The measurement temperature was 38 ° C. and the detector was RI.

(6) Residual monomer measurement After the resin was dissolved in acetone for 8 hours with shaking, the solution was poured into Shimadzu GC-14A to quantify each component. The column was 40 to 250 ° C. (6 ° C./minute temperature increase), the inlet 150 ° C., the extractor 260 ° C., and the detector was FID.
(7) Kneading After each component to be kneaded was weighed and premixed, it was melt-kneaded with a twin screw extruder (PCM-29) manufactured by Ikegai. The supply amount of the kneaded components was 70 g / min, the cylinder temperature was 120 ° C., and the residence time was 90 seconds.

(8) Resin pulverization efficiency When the kneaded styrene-acrylic resin for toner is pulverized to an average particle size of 7 μm using a lab jet manufactured by Nippon Pneumatic Industry Co., Ltd., when 150 g of raw material is supplied in 30 minutes The ratio of the pulverization amount to the supply amount was defined as the pulverization efficiency.
(9) Toner pulverization efficiency When the kneaded toner composition is pulverized to a mean particle size of 7 μm using a lab jet manufactured by Nippon Pneumatic Industry Co., Ltd. The ratio of the amount was defined as grinding efficiency. Grinding efficiency of 70% or more was at the usable level, and less than 70% was not at the usable level. More than 75% was a very good level.

(10) Toner fixability After developing a solid image on paper using a commercially available printer with the fixing device removed, the paper passes through the fixing roller using a fixing device that can change the rotation speed and temperature of the fixing roller. The developing paper was fixed at a speed of 100 mm / second and a fixing roller temperature of 175 ° C. The printed part was bent and applied with a load of 5 kg / cm ^2, and then a cellophane tape (registered trademark) was applied and peeled off. The amount of light in the printed portion before and after this operation was measured using a Macbeth light meter (light amount after cellophane peeling test) / (light amount before test) × 100. A fixing rate of 80% or more was at a usable level, and less than 80% was not at a usable level. More than 90% was at a very good level.

(11) High-temperature offset resistance After developing a solid image on paper using a commercially available printer with the fixing device removed, the paper feed speed by the fixing roller is set to 100 mm / s and the temperature of the fixing roller is changed. The developing paper was fixed, and the gloss of the fixing paper was measured. The upper limit fixing temperature at which the gloss did not decrease was measured, and the upper limit temperature of 180 ° C. or higher was at a usable level, and the temperature lower than 180 ° C. was not at the usable level. Above 190 ° C was at a very good level.

Reference Example 1 (Production of Dispersant A)
In a reaction vessel equipped with a stirrer, thermometer, and gas introduction tube, 2300 parts by weight of deionized water, 25 parts by weight of methyl methacrylate and 75 parts by weight of 3-sodium sulfopropyl methacrylate are charged, and nitrogen gas is allowed to flow for about 30 minutes. It was. The temperature was raised to 60 ° C. while stirring the contents, 0.5 parts by mass of ammonium persulfate was added, and the mixture was stirred for 3 hours and then cooled. A polymer dispersion (solid content: 3.3% by mass) having a blue-white appearance and a viscosity of 340 mPa · s (25 ° C.) was obtained.

Example 1
In a reaction vessel equipped with a stirrer and a thermometer, 160 parts by mass of deionized water, 0.04 parts by mass of sodium polyacrylate aqueous solution (solid content: 3.3% by mass), Dispersant A prepared in Reference Example 1 01 parts by weight, sodium sulfate 0.4 parts by weight, then 80 parts by weight of styrene as a monomer component, 20 parts by weight of butyl acrylate, 0.3 parts by weight of trimethylolpropane triacrylate, and benzoyl peroxide as a polymerization initiator 2 parts by mass and 0.5 parts by mass of t-butylperoxy-2-ethylhexyl monocarbonate were added. While stirring the contents, the temperature was raised from 40 ° C. to 130 ° C. over 65 minutes, and after reaching 130 ° C., the contents were further stirred for 2 hours 30 minutes and then cooled to obtain a suspension of polymer particles. The polymer was separated, washed and dried to obtain styrene-acrylic resin A.

After melt-kneading the obtained styrene-acrylic resin A with a biaxial extruder, the resulting mass was pulverized to 1 mm or less with a chopper mill manufactured by Nippon Pneumatic Industry Co., Ltd. A crushing test was carried out using a lab jet manufactured by Co., Ltd. Table 2 shows the physical properties and resin grinding efficiency of the obtained polymer.
Styrene-acrylic resin A, wax, and charge control agent shown in Table 3 are premixed and melt-kneaded with a twin screw extruder, and the resulting mass is pulverized using a chopper mill manufactured by Nippon Pneumatic Industry Co., Ltd. Then, using a laboratory jet manufactured by Nippon Pneumatic Industry Co., Ltd., the particles were pulverized to an average particle size of 7 μm to remove particles of 4 μm or less. A toner obtained by externally adding the obtained toner particles and the external additive shown in Table 3 was obtained. A printing performance evaluation and a toner pulverization test were carried out using the obtained toner. The results are shown in Table 3.

Examples 2-7
Except having changed the kind and usage-amount of the monomer component of a polymer into the value shown in Table 1, operation similar to Example 1 was performed, styrene-acrylic resin BK was obtained, and the grinding | pulverization test was implemented. did. Table 2 shows the physical properties and resin grinding efficiency of the obtained polymer.
Further, a toner was obtained in the same manner as in Example 1 except that the styrene-acrylic resin was changed to B to H. A printing performance evaluation and a toner pulverization test were carried out using the obtained toner. The results are shown in Table 3.

Comparative Examples 1-3
Except having changed the kind and usage-amount of the monomer component of a polymer into the value shown in Table 1, operation similar to Example 1 was performed, styrene-acrylic resin IJ was obtained, and the grinding | pulverization test was implemented. did. Table 2 shows the physical properties and resin grinding efficiency of the obtained polymer.
Further, a toner was obtained in the same manner as in Example 1 except that the styrene-acrylic resin was changed to I to J. A printing performance evaluation and a toner pulverization test were carried out using the obtained toner. The results are shown in Table 3.

In addition, the symbol described in Table 1 and Table 2 represents the following.
St: styrene n-BA: n-butyl acrylate n-BMA: n-butyl methacrylate MAA: methyl methacrylate TMPTA: trimethylolpropane triacrylate TMPTMA: trimethylolpropane trimethacrylate DVB: divinylbenzene 1,3-BDMA: 1,3-butanediol dimethacrylate perbutyl-O: t-butylperoxy 2-ethylhexanoate (manufactured by NOF Corporation)
Trigonox 117: t-butyl peroxy 2-ethylhexyl monocarbonate (manufactured by NOF Corporation)
# 40: Carbon black, manufactured by Mitsubishi Chemical Corporation, trade name “# 40”
S-34: Charge control agent, manufactured by Orient Chemical Co., Ltd., trade name “Bondron S-34”
RY-400: External additive, manufactured by Nippon Aerosil Co., Ltd .: Very good level
Y: Usable level ×: Not in use level

Claims (3)

  A styrene-acrylic resin for pulverized toner containing a tetrahydrofuran (THF) insoluble component and having a jet mill pulverization efficiency of 70% by mass or more.   For pulverized toner obtained by polymerizing a monomer containing a styrene monomer (a), a monofunctional (meth) acrylic monomer (b), and trimethylolpropane tri (meth) acrylate (c) 2. The styrene-acrylic resin for pulverized toner according to claim 1, which is a styrene-acrylic resin and has a mass average molecular weight of 50,000 to 500,000 in tetrahydrofuran (THF) soluble matter by gel permeation chromatography (GPC). .   A pulverized toner comprising the styrene-acrylic resin for pulverized toner according to claim 1.