JP2001305793A - Electrification controlling resin and electrostatic charge image developing toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrification controlling resin to improve the electrification characteristics of a toner and to provide the toner for development of an electrostatic charge image using the resin. SOLUTION: The electrification controlling resin consists of a vinyl copolymer exhibiting >=20 mgKOH/g acid value and having styrene monomers as the structural component. The electrostatic charge image developing toner contains the above resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charge control resin for improving the charge characteristics of a toner, and a toner for developing an electrostatic image using the same.

[0002]

2. Description of the Related Art In a typical image forming process by an electrophotographic method or an electrostatic printing method, a photoconductive insulating layer is uniformly charged, the insulating layer is exposed, and then a charge on an exposed portion is obtained. To form an electric latent image by dissipating the toner, and a developing step of visualizing the latent image by adhering a finely charged toner to the latent image, and transferring the obtained visible image to a transfer material such as transfer paper. It comprises a transfer step of transferring and a fixing step of permanently fixing by heating or pressing.

[0003] The toner used in such an electrophotographic method or the electrostatic printing method is required to have various performances in each of the above steps. For example, blocking resistance is required in which toner does not block during storage in a copier and a printer, and in a fixing process using a heat roller fixing method, a non-offset property in which a molten toner does not adhere to a heat roller or a toner on a paper. Must have good fixability.

[0004] In the developing step, the toner has a charge amount suitable for a copier and a printer without being affected by the surrounding environment such as temperature and humidity in order to attach the toner to the electric latent image. I have to do it. The chargeability of the toner is one of the most important characteristics in a system for developing an electrostatic image.

[0005] One of the methods for controlling the chargeability of the toner is to add a charge control agent (hereinafter abbreviated as CCA). For example, Japanese Patent Publication No. 41-2427 discloses that a nigrosine dye or the like can be used as a CCA for imparting a positive charge to a toner.
No. 53, JP-B-43-17955, JP-B-4
JP-A-5-26478 discloses that a metal-containing complex dye or the like can be used as a CCA for imparting a negative charge to a toner. However, many of these CCAs have a complicated structure and poor stability, and are decomposed or deteriorated by mechanical friction or shock, changes in temperature or humidity conditions, electric shock or light irradiation, and charge controllability. Was easily lost.
Further, many of the toners were colored, and most of them were not versatile for color toners.

[0006] Various studies have been made to solve such a problem of CCA, for example, US Pat. No. 4,206,064 and US Pat. No. 4,656,112.
Discloses a metal complex of salicylic acid or a derivative thereof characterized by having excellent negative chargeability, and Japanese Patent Application Laid-Open No. 63-2066969 discloses that it has excellent positive chargeability and environmental stability. Disclosed are metal complexes of aromatic oxyaldehydes.

[0007]

However, such C
CA has a problem that strong mechanical dispersion is required at the time of use because the affinity and dispersibility of the binder resin and the like, which are components of the toner, are insufficient, and the binder resin is easily cut. Was. Further, since such CCA is a compound containing a heavy metal, it has been pointed out that use of these CCA is not preferable in terms of environmental health.

[0008] The present invention has been made to solve such problems, and an object of the present invention is to provide a charge control resin for improving the charge characteristics of a toner, and an electrostatic image development using the same. To provide a toner for use.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies with the aim of solving the above problems, and as a result, it has been found that a specific vinyl copolymer gives a negative charge without using a metal compound in combination. The present inventors have found that a toner which can be used as a charge control resin and contains the same has excellent charge characteristics, and has completed the present invention.

That is, the present invention provides an acid value of 20 mgKOH /
g or more, and relates to a charge control resin characterized by being composed of a vinyl copolymer having a styrene monomer as a component, and a toner for developing an electrostatic image containing the charge control resin. It is about.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the charge control resin of the present invention, the acid value of the vinyl copolymer must be 20 mgKOH / g or more. This is because the acid value is 20mgKOH / g
If it is less than 3, the charge amount of the toner containing it is insufficient. Preferably 50 mg KOH / g
That is all. Further, the acid value of the vinyl copolymer is preferably 250 mgKOH / g or less, since the obtained toner has good charge stability under high humidity. More preferably, it is 200 mgKOH / g or less.

[0012] The vinyl copolymer used as the charge control resin of the present invention contains a styrene monomer as an essential component because the overall toner characteristics are improved.

Examples of the styrene monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn -Butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-densylstyrene, pn-dodecylstyrene, p-phenyl Styrene, 3,4-dicyclostyrene and the like can be mentioned. These can be used by appropriately selecting one or more as necessary.
Among them, styrene is preferred because the heat distortion temperature can be easily adjusted.

Further, the vinyl copolymer used as the charge control resin of the present invention contains an acid group-containing vinyl monomer as a constituent. The acid group-containing vinyl monomer that can be used is not particularly limited, but a carboxyl group-containing vinyl monomer is preferable because it tends to suppress the humidity dependence of the charge amount.

As the carboxyl group-containing vinyl monomer,
For example, acrylic acid, methacrylic acid, unsaturated monocarboxylic acids such as cinnamic acid, maleic acid, fumaric acid, unsaturated dicarboxylic acids such as itaconic acid, monomethyl maleate, monoethyl maleate, monobutyl maleate, monomethyl fumarate, Examples include unsaturated dicarboxylic acid monoesters such as monoethyl fumarate and monobutyl fumarate. One or more of these can be appropriately selected and used as necessary. Among them, methacrylic acid is preferable in terms of stability with time of the monomer and ease of handling.

Further, monomers other than the above-mentioned styrene-based monomer and carboxyl group-containing vinyl-based monomer may be used, if necessary, as a component of the vinyl-based copolymer used in the present invention. it can.

For example, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, methyl methacrylate, ethyl methacrylate, methacrylate Examples include unsaturated monocarboxylic acid ester monomers such as n-butyl acrylate, isobutyl methacrylate, propyl methacrylate, 2-ethylhexyl methacrylate, and stearyl methacrylate.

The copolymerization ratio of the monomer which is a constituent component of the vinyl copolymer used as the charge control resin of the present invention is as follows:
Although not particularly limited as long as the conditions of the present invention are satisfied,
It is preferable to select the copolymer so that the Tg (glass transition temperature) of the copolymer is 30 ° C. or higher. This is because by setting Tg to 30 ° C. or higher, the toner containing the charge control resin of the present invention tends to have good blocking resistance. More preferably, it is in the range of 40 to 100 ° C. In addition, Tg can be measured by a method such as a DSC method.

The method for producing the vinyl copolymer used as the charge control resin of the present invention is not particularly limited, and may be, for example, an emulsion polymerization method, a suspension polymerization method, a bulk polymerization method, or a solution polymerization method. It can be produced, and can also be produced by mixing resins produced by these various polymerization methods.

The content of the charge control resin of the present invention in the toner is preferably in the range of 1 to 50% by mass. This is because when the content is 1% by mass or more, the charge amount of the toner tends to be improved, and when the content is 50% by mass or less, the fixability of the toner tends to be good. It is. More preferably, 5 to 40
%, More preferably 10 to 30% by mass.

The method of adding the charge control resin of the present invention to the toner is not particularly limited. When kneading the binder resin and other materials constituting the toner, a predetermined amount is charged into an extruder or the like. And knead it.

Examples of the binder resin used in the toner for developing an electrostatic image of the present invention include a polyester resin and a styrene- (meth) acrylic resin, and a styrene- (meth) acrylic resin is preferable. This is styrene
This is because when the (meth) acrylic resin is used as the binder resin, the dispersibility tends to be good.

In the present invention, the styrene- (meth) acrylic resin suitably used as the binder resin contains a styrene monomer and a (meth) acrylate monomer as essential components. Things.

Examples of the styrene monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn -Butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-densylstyrene, pn-dodecylstyrene, p-phenyl Examples thereof include styrene and 3,4-dicyclostyrene. Examples of the (meth) acrylate-based monomer include methyl (meth) acrylate, ethyl (meth) acrylate, and (meth) acrylic acid. n-butyl, isobutyl (meth) acrylate, propyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth) a Mention may be made of acrylic acid stearyl. These monomers can be appropriately selected and used as needed, and among them, styrene and n-
Butyl (meth) acrylate is preferred.

Further, monomers other than the above-mentioned styrene-based monomer and (meth) acrylate-based monomer can be used as a constituent component of the styrene- (meth) acrylic resin as required. .

For example, unsaturated dicarboxylic diesters such as dimethyl maleate, diethyl maleate, dibutyl maleate, dimethyl fumarate, diethyl fumarate, dibutyl fumarate and the like unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid and cinnamic acid Acids, maleic acid, fumaric acid, unsaturated dicarboxylic acids such as itaconic acid, monomethyl maleate,
Carboxylic acid-containing vinyl monomers such as monoesters of unsaturated dicarboxylic acids such as monoethyl maleate, monobutyl maleate, monomethyl fumarate, monoethyl fumarate and monobutyl fumarate can be mentioned.

Styrene- (meth) used as a binder resin
The copolymerization ratio of the monomer which is a constituent component of the acrylic resin is not particularly limited, but is preferably selected so that the obtained binder resin has an acid value of 20 mgKOH / g or less. This is because the acid value of the binder resin is 20 mg KO
This is because the stability of the charge amount of the toner under high humidity tends to be improved by setting the H / g or less. More preferably, it is in the range of 10 mgKOH / g or less.

The method for producing a styrene- (meth) acrylic resin suitably used as a binder resin of the toner for developing an electrostatic image of the present invention is not particularly limited. From the viewpoint, it can be produced by a method in which the remaining monomer and the solvent are 500 ppm or less in the binder resin. For example, emulsion polymerization, suspension polymerization,
It can be produced by a bulk polymerization method or a solution polymerization method, and can also be produced by mixing resins produced by these various polymerization methods.

The Tg of the toner for developing an electrostatic image of the present invention is
Is preferably in the range of 40 to 80 ° C. This is because by setting the Tg of the toner to 40 ° C. or higher, the obtained toner has good blocking resistance,
This is because the following conditions tend to improve the fixability of the obtained toner. Preferably 50 to 70
C, more preferably 55-65C.

The toner for developing an electrostatic image of the present invention can be widely used regardless of the type of magnetic, non-magnetic, one-component, and two-component. Further, for the purpose of imparting non-offset properties, a known wax or the like can be further appropriately added as an additive. Although the type of wax is not limited, a polyolefin wax, particularly a low molecular weight polyolefin wax, is preferred. The amount of the wax added is 0. 0 to the toner.
A range of 5 to 5% by mass is preferred. This is because when the amount of waxes added is 0.5% by mass or more, the non-offset property of the obtained toner tends to be improved, and when the amount is 5% by mass or less, the fluidity of the obtained toner is good. This is because it tends to be. More preferably, 1
-3% by mass.

In the toner of the present invention, in addition to the wax described above,
If necessary, a colorant, a charge control agent, a magnetic powder, and the like can be added.

Further, the toner for developing an electrostatic image of the present invention can be prepared by, for example, kneading a mixture of the charge control resin of the present invention and the above-mentioned binder resin and additives using a kneader such as a twin screw extruder. Temperature 80
It can be manufactured by kneading in the range of -200 ° C, followed by fine pulverization and classification using a jet mill or the like. The obtained toner particles preferably have an average particle size of about 5 to 20 μm.

[0033]

The present invention will be described below in detail with reference to examples.

The acid value, charging performance, glass transition temperature (T
g) was evaluated by the following method.

(1) Acid value This is the number of mg of potassium hydroxide (KOH) required to neutralize the acid contained in 1 g of the resin, and was titrated with a KOH solution in a mixed solvent of ethanol / toluene.

(2) Charging performance 4.8 parts by mass of toner and iron powder carrier (“T
EFV200 / 300 ") 95.2 parts by mass and 2
A component developer was obtained. Using a ball mill, mix the mixture
The blow-off charge when stirring at 50 rpm for 60 minutes was measured using a Toshiba blow-off powder charge meter ("TB-500" manufactured by Toshiba Chemical Corporation). The blowing conditions were as follows: blow pressure 0.04 MPa, blow time 2
Measured in minutes.

Here, the charging performance was evaluated by 91 parts by mass of a binder resin for toner (Synthesis Example 1 below), 1 part by mass of CCA ("Bontron S-34" manufactured by Orient Chemical Co., Ltd.), and carbon black (manufactured by Mitsubishi Chemical Corporation). # 40 ") and 3 parts by mass of a polypropylene wax (" 660P "manufactured by Sanyo Chemical Industries, Ltd.) were melt-kneaded at 140 ° C using a twin-screw extruder.
Blow-off charge amount and CCA of toner having a toner particle size of 15 μm with a jet mill pulverizer and a zigzag classifier
Was calculated according to the following formula, that is, the ratio to the blow-off charge amount of the toner when the charge control resin of the present invention was used instead. Charging performance = Blow-off charge amount of toner using resin of the present invention without using CCA / C without using resin of the present invention
Blow-off charge of toner using CA

The following criterion was adopted as the value of the charging performance. 1.0 or more: charge amount is very good 0.8 or more and less than 1.0: charge amount is good 0.5 or more and less than 0.8: charge amount is slightly inferior but is at a practical level less than 0.5: charge amount Is not at a practical level

(3) Glass transition temperature After the sample was heated to 100 ° C., the temperature was raised at a rate of 10 / sec using DSC (DSC22 system, manufactured by Seiko Denshi).
It is shown by the shoulder value measured under the condition of min.

(Synthesis Example 1) 80 parts by mass of styrene, 20 parts by mass of n-butyl acrylate, 0.3 part by mass of divinylbenzene, 300 parts by mass of water, and partially saponified polyvinyl alcohol ("Gosenol GH-" manufactured by Nippon Chemical Industry Co., Ltd.) 20 ")
0.2 parts by mass, stirred, then added 3 parts by mass of benzoyl peroxide, heated to 85 ° C., performed suspension polymerization for 2 hours, and then heated to 103 ° C. Was distilled off by 20% with respect to the amount of water in the system. Furthermore, if the internal temperature is 6
The temperature was lowered to 0 ° C., and 0.5 parts by mass of sodium hydroxide was added thereto.
Thereafter, the mixture was cooled to room temperature, sufficiently washed, dehydrated, and dried to obtain a binder resin (A) for a styrene-acrylic toner. The acid value of the obtained resin is 0.1 mgKOH / g, T
g was 63 ° C.

(Synthesis Example 2) 76 parts by mass of styrene, 20 parts by mass of n-butyl acrylate, and 4 parts by mass of methacrylic acid were added to water 1
80 parts by mass and 0.2 parts by mass of partially saponified polyvinyl alcohol ("Gohsenol GH-20" manufactured by Nippon Chemical Industry Co., Ltd.) and stirred, and then t-butyl peroxy 2-ethylhexanate 1 After adding 1.5 parts by mass and 1 part by mass of t-butylperoxy 2-ethylhexyl carbonate, the temperature was raised to 130 ° C., suspension polymerization was carried out for 2 hours to complete the polymerization, and the mixture was cooled to room temperature, washed sufficiently, Charge control resin (B) that dehydrates, dries and imparts a negative charge
I got The acid value of the obtained resin was 23.7 mgKOH /
g and Tg were 61 ° C.

(Synthesis Example 3) 66 parts by mass of styrene, 25 parts by mass of n-butyl acrylate, and 9 parts by mass of methacrylic acid were mixed with 1 part of water.
80 parts by mass and 0.2 parts by mass of partially saponified polyvinyl alcohol ("Gohsenol GH-20" manufactured by Nippon Chemical Industry Co., Ltd.) and stirred, and then t-butyl peroxy 2-ethylhexanate 1 After adding 1.5 parts by mass and 1 part by mass of t-butylperoxy 2-ethylhexyl carbonate, the temperature was raised to 130 ° C., the suspension polymerization was completed for 2 hours, and the polymerization was completed. Charge control resin (C) that dehydrates, dries, and gives a negative charge
I got The acid value of the obtained resin was 55.0 mgKOH /
g and Tg were 62 ° C.

(Synthesis Example 4) 47 parts by mass of styrene, 36 parts by mass of n-butyl acrylate, 17 parts by mass of methacrylic acid, 180 parts by mass of water, partially saponified polyvinyl alcohol ("Gohsenol GH-20" manufactured by Nippon Chemical Industry Co., Ltd.) ) Was added to the mixture with 0.2 parts by mass, stirred, and then 3 parts by mass of t-butylperoxy-2-ethylhexanate and 1 part by mass of t-butylperoxy-2-ethylhexyl carbonate were added. After the temperature is raised, suspension polymerization is carried out for 2 hours to complete the polymerization, then cooled to room temperature, sufficiently washed, dehydrated, and dried to give a charge controlling resin (D) which imparts a negative charge.
I got The acid value of the obtained resin is 107.7 mgKOH /
g and Tg were 59 ° C.

(Synthesis Example 5) 56 parts by mass of styrene, 19 parts by mass of n-butyl acrylate, 25 parts by mass of methacrylic acid, 180 parts by mass of water, partially saponified polyvinyl alcohol ("Gohsenol GH-20" manufactured by Nippon Chemical Industry Co., Ltd.) ) Was added to the mixture with 0.2 parts by mass, and the mixture was stirred. Then, 1.5 parts by mass of t-butylperoxy-2-ethylhexanate and 1 part by mass of t-butylperoxy-2-ethylhexyl carbonate were added, and 130 parts by mass was added. After the temperature was raised to ° C., suspension polymerization was carried out for 2 hours to complete the polymerization, then cooled to room temperature, sufficiently washed, dehydrated, and dried to obtain a charge control resin (E) which imparts a negative charge. . The acid value of the obtained resin is 155.9 mgK.
OH / g and Tg were 105 ° C.

(Synthesis Example 6) 47 parts by mass of styrene, 20 parts by mass of n-butyl acrylate, and 180 parts by mass of 33 parts by mass of methacrylic acid in water, and partially saponified polyvinyl alcohol (“Gohsenol GH-20” manufactured by Nippon Chemical Industry Co., Ltd.) ) Was added to the mixture with 0.2 parts by mass and stirred, and then 1.5 parts by mass of t-butylperoxy-2-ethylhexanate and 1 part by mass of t-butylperoxy-2-ethylhexyl carbonate were added, and the mixture was added with 130 parts by mass. After the temperature was raised to ° C., suspension polymerization was carried out for 2 hours by performing suspension polymerization, and then cooled to room temperature, sufficiently washed, dehydrated, and dried to obtain a charge control resin (F) which imparts a negative charge. . The acid value of the obtained resin is 201.3 mgK.
OH / g and Tg were 118 ° C.

(Example 1) 78.2 parts by mass of a binder resin for toner (A) obtained in Synthesis Example 1 and a charge control resin (B)
13.8 parts by mass, carbon black (Mitsubishi Chemical Corporation "#"
40 "), 5 parts by mass, and 3 parts by mass of polypropylene wax (" 660P "manufactured by Sanyo Chemical Industries, Ltd.) were added to 1 part using a twin-screw extruder.
The mixture was melt-kneaded at 40 ° C. Next, the toner particle diameter was 15 μm and Tg62 was measured with a jet mill pulverizer and a zigzag classifier.
° C was obtained. As a result of measuring the amount of blow-off charge of the obtained toner, the charge characteristic was 0.68.

Example 2 78.2 parts by mass of a binder resin for toner (A) obtained in Synthesis Example 1 and a charge control resin (C)
13.8 parts by mass, carbon black (Mitsubishi Chemical Corporation "#"
40 "), 5 parts by mass, and 3 parts by mass of polypropylene wax (" 660P "manufactured by Sanyo Chemical Industries, Ltd.) were added to 1 part using a twin-screw extruder.
The mixture was melt-kneaded at 40 ° C. Next, the toner particle diameter was 15 μm and Tg62 was measured with a jet mill pulverizer and a zigzag classifier.
° C was obtained. As a result of measuring the blow-off charge amount of the obtained toner, the charge characteristic was 0.86.

(Example 3) 78.2 parts by mass of a binder resin for toner (A) obtained in Synthesis Example 1 and a charge control resin (D)
13.8 parts by mass, carbon black (Mitsubishi Chemical Corporation "#"
40 "), 5 parts by mass, and 3 parts by mass of polypropylene wax (" 660P "manufactured by Sanyo Chemical Industries, Ltd.) were added to 1 part using a twin-screw extruder.
The mixture was melt-kneaded at 40 ° C. Next, the toner particle diameter was 15 μm and Tg62 was measured with a jet mill pulverizer and a zigzag classifier.
° C was obtained. As a result of measuring the blow-off charge amount of the obtained toner, the charge characteristic was 0.95.

(Example 4) 78.2 parts by mass of a binder resin (A) for toner obtained in Synthesis Example 1, and a charge control resin (E)
13.8 parts by mass, carbon black (Mitsubishi Chemical Corporation "#"
40 "), 5 parts by mass, and 3 parts by mass of polypropylene wax (" 660P "manufactured by Sanyo Chemical Industries, Ltd.) were added to 1 part using a twin-screw extruder.
The mixture was melt-kneaded at 40 ° C. Next, the toner particle size was 15 μm and the Tg was 63 with a jet mill pulverizer and a zigzag classifier.
° C was obtained. As a result of measuring the blow-off charge amount of the obtained toner, the charge characteristic was 0.98.

(Example 5) 78.2 parts by mass of the binder resin for toner (A) obtained in Synthesis Example 1 and the charge control resin (F)
13.8 parts by mass, carbon black (Mitsubishi Chemical Corporation "#"
40 "), 5 parts by mass, and 3 parts by mass of polypropylene wax (" 660P "manufactured by Sanyo Chemical Industries, Ltd.) were added to 1 part using a twin screw extruder.
The mixture was melt-kneaded at 40 ° C. Next, the toner particle size was 15 μm and the Tg was 63 with a jet mill pulverizer and a zigzag classifier.
° C was obtained. As a result of measuring the blow-off charge amount of the obtained toner, the charge characteristic was 1.15.

Comparative Example 1 92 parts by weight of the binder resin for toner (A) obtained in Synthesis Example 1, 5 parts by weight of carbon black (“# 40” manufactured by Mitsubishi Chemical Corporation), and polypropylene wax (manufactured by Sanyo Chemical Co., Ltd.) "660P") 3 parts by mass were melt-kneaded at 140 ° C using a twin-screw extruder. Next, the toner particle size was 15 μm using a jet mill pulverizer and a zigzag classifier.
m and a toner having a Tg of 62 ° C. were obtained. As a result of measuring the blow-off charge amount of the obtained toner, the charge characteristic was 0.35.

[0052]

As is apparent from the above description, according to the present invention, it is possible to provide a charge control resin which improves the charge characteristics of the toner, and a toner for developing an electrostatic image using the same. It is extremely useful industrially.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yoko Harada 2-1-1, Ushikawa-dori, Toyohashi-shi, Aichi F-term in the Mitsubishi Rayon Co., Ltd. Toyohashi Plant (reference) 2H005 AA01 AA06 CA04 DA01 EA10

Claims (2)

[Claims] Claims: 1. An acid value is 20 mgKOH / g or more,
A charge control resin comprising a vinyl copolymer containing a styrene monomer as a constituent. 2. An electrostatic charge image developing toner comprising the charge control resin according to claim 1.