JP2003162096A - Binder resin and electrophotographic developing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a binder resin giving a toner having no odor and excellent blocking resistance and resistance against a plasticizer of vinyl chloride and to provide an electrophotographic developing method. <P>SOLUTION: The binder resin contained in a toner contains styrene and/or its derivatives and (meth)acrylates as the main structural components, the glass transition temperature of the binder resin is 50-100°C and the amount of residual monomers is ≤200 ppm. However, the binder resin excludes a resin which is a product of polymerization of monomers in the presence of a plasticizer by ≥10 wt.% to the total weight of the monomers and the plasticizer. Electrophotographic development is carried out using a toner containing this binder resin and a coloring agent. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a binder resin and a method for developing electrophotography.

[0002]

2. Description of the Related Art Conventionally, many inventions have been made on resins for dry toner, and various physical properties of toner have been improved. However, there are many residual monomers in conventionally used toner resins or toners,
Particularly, there is a problem that the work environment is deteriorated due to the generation of odor during melt-kneading, or the odor is generated during copying, which causes discomfort, and there is a strong demand for improvement.

In such a situation, in order to solve this problem, the polymerization temperature is maintained at the polymerization temperature or higher for a long time after completion of the polymerization, or the solid resin obtained by dehydration drying after completion of the polymerization is used in an extruder or the like. There is disclosed a method of removing residual monomers in a molten state by using. However, these methods have problems that the process is complicated and the cost is increased, and the quality is deteriorated due to melt-kneading, etc., and it is expected that a toner resin or a toner for which the amount of residual monomer is very short and the toner is very short Has been done.

[0004]

The inventors of the present invention have conducted extensive studies to achieve the above object. Surprisingly, by controlling the residual monomer in the toner resin to a specific concentration or less, the toner The odor when used as a resin and a toner is greatly improved, and the blocking resistance and PVC plasticizer resistance of the toner are also improved at the same time. Also, a specific treatment process is adopted in the resin manufacturing method. It was found that the residual monomer in the resin can be removed in a short time, and the present invention was achieved.

[0005]

SUMMARY OF THE INVENTION The gist of the present invention is a binder resin contained in a toner, the binder resin comprising styrene and / or its derivative and (meth) acrylic acid ester as main constituent components. And the glass transition point of the binder resin is 50 to
The binder resin is 100 ° C. and the residual monomer amount is 200 ppm or less (provided that the binder resin is present in an amount of 10% by weight or more based on the total weight of the monomer and the plasticizer). Except for the resin which is a polymerized product.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION First, the binder resin of the present invention will be described. As the binder resin of the present invention, a generally known radical polymer which can be produced by suspension polymerization can be applied. Specific examples of the monomer used to obtain these resins include styrene, α-methylstyrene, and p-methyl group, m-methyl group, p-methyl group, p-ethyl group, 2, as a substituent. 4-dimethyl group, p-butyl group, p-hexyl group, p-octyl group,
Styrene derivatives having p-nonyl group, p-decyl group, p-methoxy group, p-phenyl group, etc., general formula: CH
₂ = CR-COOR '(wherein R represents hydrogen or a methyl group), R'is a methyl group, an ethyl group, or n
-Propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-ventil group, n-hexyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, Acrylic esters such as isononyl group, decyl group, dodecyl group, tridecyl group, stearyl group, docosyl group, cyclohexyl group, benzyl group, phenyl group, methoxyethyl group, ethoxyethyl group, butoxyethyl group, and phenoxyethyl group or Examples thereof include vinyl esters such as methacrylic acid esters, vinyl acetate and vinyl propionate, and monomers such as acrylic acid or methacrylic acid derivatives such as acrylonitrile and methacrylonitrile. Alternatively, it may be used as a mixture.

For example, styrene and / or its derivatives,
A typical example is a monomer mixture containing (meth) acrylic acid alkyl ester as a main constituent. or,
The glass transition point (Tg) of the obtained binder resin is 50 to 100 from the viewpoint of blocking resistance and fixing property.
° C, especially 55-80 ° C is preferred. Generally, Tg is slightly different depending on the measuring method and the measuring conditions, but the Tg in the present invention is measured by a differential scanning calorimeter (hereinafter referred to as DSC) at a heating rate of 10
It is defined as the intersection of the endothermic curve near the Tg and the baseline of the chart measured as ° C / min.

In the present invention, the amount of residual monomer in the binder resin needs to be 200 ppm or less. If the amount of the residual monomer exceeds 200 ppm, the blocking resistance and the PVC plasticizer resistance decrease, and the problem of odor remains, which is not preferable. The residual monomer amount is preferably 110 pp
The range is m or less, more preferably 90 ppm or less. The amount of residual monomer in the binder resin is 20
As a specific method for adjusting the content to 0 ppm or less, a monomer mixture constituting a binder resin is synthesized by a polymerization method such as suspension polymerization, and then the dispersion is dispersed while heating at a temperature of Tg or higher of the resin to be obtained. Water of 5 to 50% by weight with respect to the amount of water in the liquid is distilled off as steam. Further, by introducing a larger amount of air, nitrogen, or the like, or by heating up to near the boiling point of the dispersion liquid, the purpose can be achieved in a shorter time.

In the present invention, the heating temperature for distilling water as water vapor needs to be higher than the Tg of the resin to be obtained, and if it is lower than Tg, the residual monomer in the resin is trapped in the resin, It is difficult to reduce the amount of residual monomer to 200 ppm or less. In the above method, the amount of water to be distilled off needs to be 5% by weight or more based on the amount of water in the resin dispersion after suspension polymerization, and if it is lower than this, the residual monomer in the resin is 200 ppm or less. Difficult to do. Further, even if it exceeds 60% by weight, the effect of reducing the residual monomer is small, and problems such as secondary aggregation of the resin and an increase in the amount of cullet are likely to occur, which is not preferable.

The suspension polymerization in the present invention is carried out by a known method until the polymerization is substantially completed. First, in a reactor equipped with a thermometer, 1 to 10 times, preferably 2 to 4 times, water, a suspension dispersion stabilizer and, if necessary, a dispersion aid are added to a monomer and stirred, and then at room temperature or While heating, a monomer, a polymerization initiator and, if necessary, a chain transfer agent are added and heated to a predetermined polymerization temperature to substantially complete the polymerization, that is, until the polymerization rate reaches at least 95%. Keep warm.

As the polymerization initiator in the present invention, a known initiator having radical polymerization activity is used. Specific examples thereof include di-t-butyl peroxide, t-butyl cumyl peroxide, digyl peroxide, acetyl peroxide, isobutyryl peroxide, octanonyl peroxide, decanoyl peroxide, lauroyl peroxide, and 3 , 5,5-Trimethylhexanoyl peroxide, benzoyl peroxide, m-toluoyl peroxide, t-butyl peroxyacetate, t-butyl peroxyisobutyrate, t-butyl peroxypiperate, t-butyl peroxide Oxy neodecanoate,
Cumylperoxy neodecanoate, t-butylperoxy 2-ethylhexanoate, t-butylperoxy 3,5,5-trimethylhexanoate, t-butylperoxylaurate, t-butylperoxybenzoate , T-butylperoxyisopropyl carbonate and the like. Among them, octanonyl peroxide, decanonyl peroxide, from the viewpoint of maintaining the polymerization activity for monomers and completing the polymerization in a relatively short time,
Lauroyl peroxide, benzoyl peroxide, m
-Peroxides such as toluoyl peroxide are particularly useful in the present invention. Other than these, azo compounds such as azobisisobutyronitrile and 2,2'-azobis- (2,4-dimethylvaleronitrile) can be mentioned. These polymerization initiators are used in an amount necessary for completing the polymerization in a relatively short time, but generally 0.1 to 10 parts by weight, preferably 0.5 to 100 parts by weight of the monomer. To 5 parts by weight are used. The present invention is applied when a peroxide is used as at least a part of the polymerization initiator, and an azo compound, for example, azobisisobutylnitrile or 2,2′azobis- (2,4-dimethylvaleronitrile) is partially used. It is also included when used in combination.

Known chain transfer agents used in the present invention as needed include, for example, n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, and 2-ethylhexyl thioglycolate. it can. If these chain transfer agents remain in the resin, they cause a bad odor at the time of melting, and therefore should be minimized when used.

Known suspension-dispersion stabilizers are used in the present invention. Specific examples thereof include polyvinyl alcohol, partially saponified polyvinyl alcohol, sodium or potassium salts of homopolymers or copolymers of acrylic acid or methacrylic acid, carboxymethyl cellulose, gelatin, water-soluble resins such as starch, barium sulfate, Examples thereof include poorly water-soluble or insoluble inorganic powders such as calcium sulfate, barium carbonate, calcium carbonate, magnesium carbonate and calcium phosphate. These suspension-dispersion stabilizers are used in an amount necessary to complete the operation without causing the resin particles produced to solidify during polymerization and treatment with an alkali and a solvent (hereinafter referred to as alkali / solvent treatment). Generally, 0.01 to 5 parts by weight, preferably 0.05 to 2 parts by weight, is used with respect to 100 parts by weight of water. In addition, examples of the dispersion aid used in the present invention include electrolytes such as sodium chloride, potassium chloride, sodium sulfate and potassium sulfate.

The conditions for suspension polymerization in the present invention vary depending on the type of monomer to be polymerized and the type and amount of polymerization initiator, but the temperature is generally 50 to 130 ° C., preferably 70 to 100 ° C., and the time is About 1 to 10 hours is suitable. In the present invention, the toner contains at least the binder resin as described above and a coloring agent such as carbon black, and the residual monomer amount of the toner is reduced by reducing the residual monomer amount of the binder resin used. It will be reduced.

The composition ratio of each component in the toner is not particularly limited, and may be the same ratio as that of a commonly used toner. For example, the binder resin and the colorant can be used in a weight ratio of about 60 to 98: 2 to 40. The toner is, for example, a mixture of a binder resin and a colorant, which is kneaded at a temperature of about 150 ° C. using a kneader such as a twin-screw extruder, and then finely pulverized and classified using a jet mill or the like. Then, the toner is formed. The obtained toner particles have an average particle size of 5
It is preferably about 15 μm. In addition to the binder resin and the colorant, additives such as a charge control agent, an anti-offset agent, and magnetic powder may be used in the toner.

[0016]

EXAMPLES Next, the present invention will be described with reference to examples. In the examples, the number of parts means part by weight unless otherwise specified. Examples 1 to 3, Comparative Example 1 79.7 parts of styrene, 20 parts of n-butyl acrylate,
0.3 part of divinylbenzene was added to a mixture of 300 parts of water and 0.2 part of partially saponified polyvinyl alcohol (Nippon Kagaku Kogyo Co., Ltd. Gohsenol GH-20) and stirred, and then 3 parts of benzoyl peroxide was added. After the temperature was raised to 85 ° C., suspension polymerization was carried out for 2 hours to complete the polymerization. Then, the temperature was raised to 103 ° C., and as shown in Table 1, water was distilled off by 5%, 20%, 40%, and 50% of the amount of water in the system. When the residual monomer in the obtained resin was measured by gas chromatography, it was 200 ppm,
It was 110 ppm, 90 ppm and 80 ppm. Also, add 6
Those that tried to distill out 0% had a large amount of secondary agglomeration on the way,
The resin powder for the toner was not obtained, and the operation was stopped.

To 92.5 parts of each resin thus obtained, 5 parts of carbon black (# 30 manufactured by Mitsubishi Kasei Kogyo Co., Ltd.) and a charge control agent (Bontron S-3 manufactured by Orient Chemical Co., Ltd.) were used.
1) Twenty-five parts were kneaded with a twin-screw extruder at 150 ° C. for about 5 minutes, cooled, and then finely pulverized with a jet mill to collect particles of 5 to 15 μm to produce a toner. Regarding the toner manufactured,
The Tg of each was measured to evaluate blocking resistance, vinyl chloride plasticizer resistance, and odor. The results obtained are shown in Table 1. Comparative Examples 2 to 4 Immediately after completion of suspension polymerization in the same manner as in Examples 1 to 3, the resin was taken out immediately, the temperature was raised to 92 ° C. after the polymerization and the resin was taken out after being held for 2 hours, and the polymerization. Immediately after taking out the resin, it is dried at 50 ° C. for 20 hours and then 150
The same evaluations as in Examples 1 to 3 were carried out for those treated with the residual monomer through an extruder at 5 ° C for 5 minutes. The results obtained are shown in Table 1.

[0018]

[Table 1]

[0019]

As described in detail above, according to the present invention,
By using a binder resin having a small amount of residual monomer in the toner, the toner exhibits no odor and exhibits excellent blocking resistance and vinyl chloride plasticizer resistance.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Ryo Funato             4-1-1 Sunadabashi, Higashi-ku, Nagoya-shi, Aichi               Within Mitsubishi Rayon Co., Ltd. (72) Inventor Keiji Yoshida             4-1-1 Sunadabashi, Higashi-ku, Nagoya-shi, Aichi               Within Mitsubishi Rayon Co., Ltd. F-term (reference) 2H005 AA01 CA04 CA30 EA03 EA10

Claims (2)

[Claims] 1. A binder resin contained in a toner, wherein the binder resin contains styrene and / or a derivative thereof and (meth) acrylic acid ester as main constituent components, and the glass of the binder resin. The transition point is 50 to 100 ° C., and the residual monomer amount is 200.
Binder resin characterized by being below ppm. However, the resin which is a polymer obtained by polymerizing the binder resin in the presence of 10% by weight or more of the plasticizer with respect to the total weight of the monomer and the plasticizer is excluded. 2. A developing method comprising developing an electrophotographic image using the toner containing the binder resin according to claim 1 and a colorant.