JPH1026843A - Production of toner resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively remove an org. solvent and residual monomers from an org. solvent soln. of a toner resin by separating a solvent recovering tank from a solvent recovering system after most of the org. solvent is removed from the org. solvent soln. of the resin and then removing the solvent from the soln. SOLUTION: First, the whole line to remove an Org. solvent is evacuated by opening valves 9, 10 and operating a vacuum pump 5. Hot water is circulated through a heating jacket 6 of a reaction chamber 1 to stir and heat the org. solvent soln. of the toner resin in the reaction chamber 1. The solvent vaporized from the resin soln. is passed through a pipe 20 to an org. solvent cooling device 3 where the solvent is cooled and solidified. Then, the solvent is passed through the valve 9 and accumulated in a solvent recovering tank 2. Then, valves 9, 10 are closed to separate the solvent recovering tank 2 from the line to remove the org. solvent. Since the vacuum pump 5 is continuously operated, the vacuum degree in the line is improved and an org. solvent in the org. solvent soln. in the reaction chamber 1 is again vaporized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a resin composition for toner used in electrophotography and the like.

[0002]

2. Description of the Related Art In electrophotography and the like, a dry development method is frequently used as a method for developing an electrostatic charge image. In the dry development method, usually, toner is charged by friction with iron powder or glass beads called a carrier, and this is electrically attracted to an electrostatic latent image formed on a photoreceptor and adheres. This is transferred to a sheet and fixed by a heat roll to form a permanent visible image.

[0003] A resin composition for a toner is required to have a high-speed copying property, and is composed of a high molecular weight polymer component and a low molecular weight polymer component. Performance that does not stain (non-offset properties), performance in which the toner adheres firmly to the paper at a low temperature and the visible image does not fall off (fixing property), and performance that the toner particles do not aggregate in the copying machine (blocking resistance) Are required.

In recent years, as the copying speed has been increased and the fixing roll has been heated to a higher temperature, in addition to the above-described performance, when the toner is fixed on paper by a hot roll, the resin for the toner is thermally decomposed or remains. There have been problems such as the monomer and the residual solvent being volatilized by heat and giving off a bad smell.

As a method for solving these problems, JP-A-48-65945 and JP-A-52-113737 have been proposed.
In Japanese Patent Application Laid-Open Publication No. H11-146, a method is disclosed in which a fragrance is added to a toner raw material to prevent an odor. However, these methods are not a method of removing the bad smell and do not solve the fundamental problem.

[0006] Japanese Patent Application Laid-Open No. 58-37002 discloses that
A method is disclosed in which, when polymerizing a resin for toner, two or more radical initiators having different half-lives are used in combination and the polymerization temperature is changed to carry out polymerization in two or more stages. However, this method can improve the conversion of a monomer into a resin, but cannot exert an effect on removing a devolatilizing component of a resin for a toner such as an organic solvent.

Furthermore, Japanese Patent Application Laid-Open No. 55-15645 discloses a method for removing residual monomers from a thermoplastic resin using a devolatilizer having a specific structure. To be less than 2
The temperature must be raised to 50 to 280 ° C., and oxidative deterioration of the resin may occur at the same time. In addition, the effect cannot be exhibited in removing the devolatilizing component of the toner resin mediated by the organic solvent.

[0008]

SUMMARY OF THE INVENTION As described above, the present invention solves the problem of residual monomers and solvent volatile components remaining in a resin for toner by using a solution of a resin for toner in an organic solvent. An object of the present invention is to provide a method for producing a resin composition for a toner, which effectively removes an organic solvent and residual monomers.

[0009]

According to the method for producing a resin composition for a toner of the present invention, the organic solvent in a reaction vessel is depressurized when the solvent for the resin composition for a toner is removed.
A first step of storing the solvent in a solvent recovery tank through an organic solvent cooling device; and a second step of removing the solvent by closing the solvent recovery tank from the solvent recovery system under the same reduced pressure. It is characterized by having.

[0010] The resin composition for toner usually contains a high molecular weight polymer and a low molecular weight polymer as main components, and metal soaps, waxes, heat stabilizers and the like are appropriately compounded. Using the resin composition as a binder, a colorant, a charge control agent, and, if necessary,
It is manufactured by mixing, melting, kneading and pulverizing.

The high molecular weight polymer and the low molecular weight polymer, which are the main components of the resin composition for a toner, generally comprise a vinyl copolymer, and are prepared by bulk polymerization, suspension polymerization, emulsion polymerization of various vinyl monomers. And a solution polymerization method. However, in particular, but not limited to, the method for producing a high molecular weight polymer is selected from a bulk polymerization method, a suspension polymerization method, and an emulsion polymerization method in terms of technically easy production of a high molecular weight polymer. In addition, as a method for producing a low-molecular-weight polymer, a solution polymerization method is often selected, including reduction in molecular weight by chain transfer of a solvent.

In producing a resin composition for a toner, when modifying a high molecular weight polymer or a low molecular weight polymer, blending a third component, or uniformly dispersing these components, the constituent components are When dissolved in an organic solvent, the resin composition for a toner is often prepared in the form of a solution, in that uniform reaction and uniform dispersion are easy.

The resin composition solution for toner used in the present invention means a resin composition solution at a stage where the organic solvent is removed to become a resin composition for toner. It is an organic solvent solution of a vinyl copolymer composed of a high molecular weight polymer, and the composition, production method and the like may be any.

The vinyl copolymer constituting the high molecular weight polymer and the low molecular weight polymer is a copolymer of a usual vinyl monomer, and the weight average molecular weight of the former is 50,000 to 1
The weight average molecular weight of 200,000 is preferably used in the range of 200,000 to 2,000,000, and the type of the vinyl monomer is not particularly limited, but a styrene monomer, a (meth) acrylate monomer, Examples thereof include vinyl chloride, vinyl acetate, and vinyl ether, and at least one of them is used. Among them, a styrene monomer and a (meth) acrylate monomer are preferably used.

Examples of the styrene monomer include styrene, o-methylstyrene, m-methylstyrene and p-methylstyrene.
-Methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, pt-butylstyrene, pn-hexylstyrene, pn-octylstyrene, p Styrene monomers such as -n-dodecylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, and 3,4-dichlorostyrene;

The (meth) acrylate monomers include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and the like.
N-butyl (meth) acrylate, isobutyl (meth) acrylate, alkyl n-octyl, dodecyl (meth) acrylate, 2-ethylhexyl (meth) acrylate,
Stearyl (meth) acrylate, (meth) acrylic acid 2
-Chloroethyl, phenyl (meth) acrylate, α-methyl methyl acrylate and the like.

The initiator for the vinyl copolymer is not particularly limited, and any ordinary radical initiator may be used. Examples thereof include benzoyl peroxide, lauryl peroxide, methyl ethyl ketone peroxide, sodium persulfate, Examples thereof include ammonium persulfate, and at least one of them is used.

The organic solvent used in the resin composition solution for toner may be of any type as long as the constituent high molecular weight and low molecular weight copolymers are both organic solvents that can be dissolved. Aliphatic hydrocarbons such as hexane, heptane and octane; aromatic hydrocarbons such as toluene, xylene and ethylbenzene; halogenated hydrocarbons such as trichloroethylene, dichlorobutane and propyl chloride; nitrohydrocarbons such as nitropropane, nitrobutane and nitrobenzene; Alcohols such as isopropyl alcohol, n-butyl alcohol and isobutyl alcohol; ethers such as ethyl butyl ether and butyl ether; ketones such as methyl ethyl ketone, methyl propyl ketone and diethyl ketone; butyl formate; ethyl acetate;
Esters such as propyl acetate are exemplified, and at least one of them is used.

The first step in the production method of the present invention is a step of storing the organic solvent in the reaction vessel in a solvent recovery tank through an organic solvent cooling device under reduced pressure, It is composed of a container, an organic solvent cooling device, a solvent recovery tank, and a vacuum pump. These devices are connected by a pipeline and can be reduced in pressure by a vacuum pump. The organic solvent solution in the reaction vessel is heated without stirring, and the organic solvent evaporates actively under reduced pressure. The evaporated organic solvent is cooled by the organic solvent cooling device and immediately aggregates,
Stored in the solvent recovery tank.

The second step is a step of closing the solvent recovery tank from the solvent recovery system and removing the solvent under the same reduced pressure, and comprises a reaction vessel, an organic solvent cooling device, a solvent recovery tank, The solvent recovery tank filled with the organic solvent is closed and removed from the organic solvent removal line constituted by the vacuum pump (that is, the solvent recovery system), and the reaction vessel and the vacuum pump are directly connected under the same reduced pressure, This is the step of removing the solvent.

(Action) After most of the organic solvent has been removed from the resin organic solvent solution in the first step, the solvent recovery tank is closed in the second step. Since the vapor pressure of the organic solvent in the tank is not newly replenished, the depressurizing capacity of the vacuum pump is improved accordingly, and the degree of vacuum in the second step is higher than that in the first step. . Therefore, in the second step, even a trace amount of the organic solvent can be removed. Therefore, according to the method for producing a resin composition for a toner of the present invention, not only the organic solvent in the resin composition for a toner but also residual monomers can be directly removed.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to further clarify the present invention,
This will be described more specifically with reference to the reaction flowchart shown in FIG. The apparatus for producing a resin composition for a toner of the present invention includes a reaction vessel 1, a solvent recovery tank 2, an organic solvent cooling device 3, a cold trap 4, a vacuum pump 5, a reaction vessel heating jacket 6, valves 7, 8, 9, 10, 11, 1
2. It is composed of a device such as a viewing window 13 of the reaction vessel.

In the first step of desolvation, the reaction vessel 1
In the above, the resin solution of the organic solvent is stirred in a state where 50 to 80% of the volume capacity of the reaction vessel is filled. Next, the valves 7, 8, 11, and 12 are closed, and the valves 9, 10
Is opened, and the organic solvent cooling device 3 is cooled by passing a coolant such as water, and a vacuum pump 5 such as an aspirator is operated to bring the entire organic solvent removing line into a reduced pressure state. Thereafter, when the resin solution is stirred and heated by circulating steam, heating oil or hot water through the reaction vessel heating jacket 6, the solvent evaporates from the resin solution actively at a boiling point or lower according to the degree of vacuum. . The vaporized solvent passes through the pipe 20, is cooled and aggregated by the organic solvent cooling device 3, passes through the valve 9, and is accumulated in the solvent recovery tank 2. The solvent that cannot be aggregated by the organic solvent cooling device 3 passes through the pipe 21 and is further cooled by the cold trap 4 to be aggregated and liquefied and collected.

As the solvent removal proceeds, the viscosity of the resin solution in the reaction vessel 1 gradually increases, and vigorous bubbling in the reaction vessel is observed through the viewing window 13 of the reaction vessel. . When the bubbles of the boiling solution reach a position immediately below the viewing window 13, nitrogen gas is introduced from the valve 12 into the reaction vessel. When the rise of the solution stops, the introduction of nitrogen gas is stopped. When the liquid level of the solution rises again, this operation is repeated. Finally, when the liquid level no longer rises, the first step is completed.

In the second step of desolvation, the valve 9,
10 is closed, and the solvent recovery tank 2 is removed from the organic solvent removal line (that is, the solvent recovery system). Thus, the reaction vessel 1, the organic solvent cooling device 3, and the cold trap 4
Since the vacuum pump 5 is kept operating, the reduced pressure state is maintained, and the vapor pressure of the solvent in the solvent recovery tank 2 is not newly supplied to the solvent recovery system. Therefore, the degree of vacuum of the solvent recovery system in the second step is higher than the degree of vacuum in the first step, and the organic solvent solution in the reaction vessel evaporates and bubbling again, and the organic solvent contained therein evaporates, The liquid level rises. When the bubbles of the boiling solution reach a position immediately below the viewing window 13, nitrogen gas is introduced from the valve 12 into the reaction vessel. When the rise of the solution stops, the introduction of nitrogen gas is stopped. When the liquid level of the solution rises again, this operation is repeated. Finally, when the liquid level no longer rises, the second step is completed.

By the above first and second steps, a deorganizing solvent can be achieved from the organic solvent solution of the resin composition for toner, and it is possible to prevent the generation of offensive odor during copying to a sufficient extent for practical use. it can.

Next, the production method of the present invention will be described more specifically with reference to examples and comparative examples. Example 1 1) Preparation of Resin Composition for Toner As shown in the reaction chart of FIG. 1, a 500-liter capacity reaction vessel 1 equipped with a stirrer was charged into a styrene-n-butyl acrylate copolymer (composition: styrene). : 80% by weight,
N-butyl acrylate: 20% by weight, weight average molecular weight;
(600,000), and 50 kg of toluene and 90 kg of toluene were charged and stirred, and heated to the reflux temperature of toluene while heating oil was passed through the jacket 6 of the reaction vessel 1 to prepare the high molecular weight copolymer solution. .

Next, 150 kg of styrene, 30 kg of n-butyl acrylate, and 10 kg of di-t-butyl peroxide as a radical initiator were dissolved to prepare a monomer mixed solution. From a mixed monomer tank not shown in FIG. Over 5 hours, the solution was dropped into the reaction vessel 1 to perform solution polymerization, and a polymer of a low molecular weight styrene-n-butyl acrylate copolymer and a high molecular weight styrene-n-butyl acrylate copolymer A mixed solution was obtained.

2) Recovery of Organic Solvent (First Step) While stirring the polymer mixed solution in the reaction vessel 1, 18
The temperature is raised to 0 ° C., the valves 7, 8, 11, and 12 are closed, the valves 9 and 10 are opened, and the vacuum pump 5 is operated, and the reaction vessel 1, the solvent recovery tank 2, the organic solvent cooling device 3, the cold trap 4 Was placed under reduced pressure. Thus, the solvent evaporated from the polymer mixed solution was cooled by the organic solvent cooling device 3 and accumulated in the solvent recovery tank 2. At the same time, the viewing window 1
From 3, observe the stirred and heated solution, and when the liquid level rises below the viewing window 13 with bubbles, open the valve 12 and
Nitrogen gas was introduced into the reaction vessel 1 to perform a quick purge. This operation was repeated until the liquid level of the polymer mixed solution did not rise again even when the valve 12 was closed.
During this time, the recovery of the organic solvent continued effectively.

3) Removal of Trace Solvent (Second Step) The valves 9 and 10 were closed, the solvent recovery tank 2 was placed outside the solvent recovery system, and the reduced pressure was maintained. Observing from the viewing window 13, if the liquid level of the polymer mixed solution in the reaction vessel 1 rises again and rises below the viewing window 13, the valve 12 is opened, and nitrogen gas is introduced. A quick purge was performed. This operation was repeated until the liquid level of the polymer mixed solution did not rise again even when the valve 12 was closed, and finally until the degree of vacuum became 5 mmHg or less. During this time, the recovery of the organic solvent continued effectively, and the solvent toluene accumulated in the cold trap 4.

4) Preparation of Toner The toner resin obtained by the above method was taken out of the reaction vessel 1 and purified by a usual method. 5 parts by weight of carbon black (manufactured by Mitsubishi Chemical Corporation, Diamond Black SH) was mixed with 100 parts by weight of the obtained toner resin,
Roll kneading at 60 ° C. for 5 minutes, cooling, coarse pulverization, fine pulverization with a jet mill to an average particle size of 11 μm, and hydrophobic silica fine powder (manufactured by Nippon Aerosil Co., Ltd., trade name: R972) 5 parts by weight were mixed to prepare a toner.

Comparative Example 1 A toner was prepared in the same manner as in Example 1 except that the item of 3) removal of a trace amount of solvent was omitted.

Using the resin composition for toner obtained in Example 1 and Comparative Example 1 and the toner obtained using the same, the amount of residual monomer, the amount of residual solvent, and the odor generated during copying are reduced. evaluated. The results, as shown in Table 1, in the examples, as compared with the comparative example, the residual monomer amount, the residual solvent amount,
Also, the odor generated during copying was extremely small.

[0034]

[Table 1]

[0035]

According to the production method of the present invention, the resin composition for a toner and the toner, which have an amount of residual monomer, an amount of residual solvent, and an odor generated at the time of copying, which are extremely small, since they are constituted as described above. Is obtained.

[Brief description of the drawings]

FIG. 1 is a reaction flowchart showing one example of a method for producing a resin composition for a toner.

[Explanation of symbols]

 1: Reaction container 2: Solvent recovery tank 3: Organic solvent cooling device 4: Cold trap 5: Vacuum pump 6: Reaction container heating jacket 6 7, 8, 9, 10, 11, 12: Valve 13: Looking into the reaction container window

Claims (1)

[Claims] A first step of storing an organic solvent in a reaction vessel in a solvent recovery tank through an organic solvent cooling device in a reduced pressure state when desolvating the resin composition solution for toner; And a second step of closing the solvent recovery tank from the solvent recovery system and removing the solvent under the same reduced pressure state.