JP2016180541A - Flash drying system and resin particle drying method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flash drying system and a resin particle drying method that enable reduction in a content of coarse powder and suppression of an increase in a moisture percentage compared to the case where a temperature Tin of gas made to flow into a flash dryer exceeds a glass transition temperature Tg of resin particles, in drying treatment that is performed by using the flash drying system including a material supply device for supplying the resin particles, the flash dryer for drying the resin particles by using gas and a recovering device for recovering the resin particles.SOLUTION: A flash drying system includes: a material supply device 12; a flash dryer 14; a recovering device 16; temperature detection means T1 for detecting Tin; humidity detection means H1 for detecting relative humidity Hout of gas discharged from the recovering device 16; gas temperature control means for controlling Tin to a temperature equal to or lower than Tg of resin particles; and supply amount adjustment means for adjusting the supply amount of the resin particles to control Hout to 45% RH or lower. A resin particle drying method is for controlling Tin and Hout to the above ranges.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an airflow drying system and a method for drying resin particles.

  As a drying system and drying method for resin particles such as toner for developing an electrostatic image in a wet state, there are a drying system and a drying method using various dryers such as a fluidized bed dryer, an air flow dryer, and a vacuum dryer. For example, a drying system and a drying method for drying resin particles with an air flow dryer and collecting the dried resin particles with a collecting device such as a cyclone and a bag filter have been studied.

  Patent Document 1 discloses a toner drying system that dries toner after forming toner particles in an aqueous medium, and includes (a) a drying unit that dries the toner in an air current, and (b) the temperature of the air current. Temperature detection means for detecting; (c) temperature adjustment means for controlling the temperature of the airflow; (d) humidity detection means for detecting the relative humidity of the airflow; and (d) humidity data from the humidity detection means. After detecting the inflection point of the humidity change curve, the temperature is controlled by the temperature adjusting means of (c) so that the temperature detected from the temperature detecting means of (b) can be controlled to the same temperature as before the inflection point, A toner drying system characterized by completing toner drying, and a toner drying method for drying toner after forming toner particles in an aqueous medium, wherein the toner is dried in an air stream and dried. Relative humidity of airflow from time Reaching the time the inflection point, lowering the output of the temperature adjustment means, keeping the temperature of the air flow constant, method of drying toner, characterized in that the drying of the toner is described.

JP 2007-004135 A

  An object of the present invention is to provide an airflow drying system having a raw material supply machine for supplying resin particles, an airflow dryer for drying resin particles with gas, and a recovery device for recovering the resin particles dried by the airflow dryer. In the drying process carried out, the content of the coarse powder due to the aggregation of the resin particles of the recovered resin particles is reduced compared with the case where the temperature of the gas flowing into the air dryer exceeds the glass transition temperature of the resin particles. Another object of the present invention is to provide an airflow drying system and a resin particle drying method in which an increase in the moisture content is suppressed.

  The invention according to claim 1 is a raw material supply device that supplies resin particles, an air flow dryer that dries resin particles with gas, a recovery device that recovers resin particles dried by the air flow dryer, and the air flow drying Temperature detecting means for detecting the temperature of the gas flowing into the machine, humidity detecting means for detecting the relative humidity of the gas discharged from the recovery device, and the temperature of the gas flowing into the air dryer is changed to a glass transition of the resin particles. Airflow drying comprising gas temperature control means for controlling the temperature below the temperature, and supply amount adjustment means for adjusting the supply amount of the resin particles to control the relative humidity of the gas discharged from the recovery device to 45% RH or less System.

  The invention according to claim 2 is a resin particle supply step of supplying resin particles from a raw material supply machine to an airflow dryer for drying resin particles by gas, and drying for drying the supplied resin particles using the airflow dryer. And a recovery step of recovering the resin particles dried by the airflow dryer using a recovery device, and controlling the temperature of the gas flowing into the airflow dryer below the glass transition temperature of the resin particles, and The resin particles are dried by controlling the relative humidity of the gas discharged from the recovery device to 45% RH or less.

  According to the first aspect of the present invention, an air flow having a raw material supply unit that supplies resin particles, an air flow dryer that dries the resin particles with gas, and a recovery device that recovers the resin particles dried by the air flow dryer. In the drying system, compared to the case where the temperature of the gas flowing into the air dryer exceeds the glass transition temperature of the resin particles, the content of the coarse powder due to the aggregation of the resin particles is reduced, and the recovered resin particles An airflow drying system in which an increase in moisture content is suppressed is provided.

  According to the invention which concerns on Claim 2, the resin particle supply process which supplies the resin particle from a raw material supply machine to the airflow dryer which dries the resin particle with gas, and dries the supplied resin particle using an airflow dryer In a drying method including a drying step and a recovery step of recovering resin particles dried by an air dryer using a recovery device, the temperature of the gas flowing into the air dryer exceeds the glass transition temperature of the resin particles; In comparison, there is provided a method for drying resin particles in which the content of coarse powder due to aggregation of resin particles is reduced and an increase in the moisture content of the recovered resin particles is suppressed.

It is a schematic block diagram which shows an example of a structure of the airflow drying system which concerns on embodiment of this invention. It is a schematic block diagram which shows an example of a structure of the air dryer used for the airflow drying system which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, this embodiment described below is an example for carrying out the present invention, and the present invention is not limited to this embodiment.

<Airflow drying system>
The air flow drying system (hereinafter also referred to as “drying system”) according to the present embodiment includes a raw material supply unit that supplies resin particles, an air flow dryer that dries resin particles with gas, and resin particles that are dried by the air flow dryer. A recovery device that collects the gas, a temperature detection means that detects the temperature of the gas flowing into the air dryer, a humidity detection means that detects the relative humidity of the gas discharged from the recovery device, and a gas that flows into the air dryer Gas temperature control means for controlling the temperature below the glass transition temperature of the resin particles and supply amount adjusting means for adjusting the supply amount of the resin particles to control the relative humidity of the gas discharged from the recovery device to 45% RH or less And at least.

  An example of a specific configuration of the drying system according to the present embodiment is shown in FIG. A drying system 10 shown in FIG. 1 includes a raw material supplier 12, an air dryer 14, a cyclone 16 as a recovery device, a dehumidifier 20, a discharge blower 22, a heater 24, a transfer pipe 26, and a recovery container. 28, a fine powder collecting bag filter 30, an exhaust blower 32, a temperature detecting means T1, and a humidity detecting means H1.

  FIG. 2 shows a more detailed structure of the air dryer 14 shown in FIG. The air dryer 14 shown in FIG. 2 includes a loop pipe 40, a raw material supply port 42, a discharge port 44, a gas supply unit 46, a gas discharge nozzle 48, and a temperature detection means T1.

  Hereinafter, although the specific example of the continuous drying process of the resin particle using the drying system 10 shown in FIG. 1 and the airflow dryer 14 shown in FIG. 2 is shown, the drying system which concerns on this embodiment is described in FIG. 1 and FIG. However, the present invention is not limited to the embodiment.

  In the drying system 10 shown in FIG. 1, the gas inlet (the gas supply unit 46 shown in FIG. 2) of the airflow dryer 14 is connected to the discharge side of the discharge blower 22 via the heater 24. A dehumidifier 20 that dehumidifies the gas flowing into the discharge blower 22 is connected to the suction side of the discharge blower 22. Further, the outlet of the raw material supplier 12 is connected to the raw material supply port of the air dryer 14 (the raw material supply port 42 shown in FIG. 2). The discharge port (discharge port 44 shown in FIG. 2) of the air dryer 14 is connected to the gas inlet pipe of the cyclone 16 through the transfer pipe 26. The gas discharge pipe 50 of the cyclone 16 is connected to the inlet of the bag filter 30, and the suction side of the exhaust blower 32 is connected to the bag filter 30. In the drying system shown in FIG. 1, the temperature detection means T1 is provided at the gas inlet (the gas supply section 46 shown in FIG. 2) of the air dryer 14, and the humidity detection means H1 is connected to a pipe connected to the gas discharge pipe 50 of the cyclone 16. Is provided.

  In the drying system shown in FIG. 1, the gas dehumidified through the dehumidifier 20 is pushed out by the discharge blower 22 and heated by the heater 24 to become a high-temperature dry gas, and is supplied to the gas supply unit 46 that covers the gas discharge nozzle 48. Inflow. As a result, high-temperature dry gas is supplied from the at least one gas discharge nozzle 48 into the airflow dryer 14. At this time, the temperature detection means T1 detects the temperature Tin of the dry gas flowing from the gas supply unit 46 into the air dryer. On the other hand, the wet particles supplied into the air dryer 14 are carried to the raw material supply port 42 by the raw material supplier 12.

  In the air dryer 14 shown in FIG. 2, a raw material supply port 42, at least one gas discharge nozzle 48 that discharges gas, and a discharge port 44 are provided along the loop pipe 40 in this order. In the air dryer 14 shown in FIG. 2, three gas discharge nozzles 48 are provided. The high-temperature dry gas supplied to the gas supply unit 46 is discharged into the loop pipe 40 through the gas discharge nozzles 48, and becomes an air flow swirling in the loop pipe 40. From the raw material supply port 42, wet resin particles (hereinafter also referred to as “wet particles”) are supplied into the loop pipe 40. The supplied wet particles swirl in the loop pipe 40 together with the dry gas, and the resin particles (hereinafter also referred to as “dry particles”) subjected to the drying process by the air dryer 14 are discharged from the discharge port 44 together with the gas.

  As described above, in the air dryer 14, the dry gas supplied from the gas discharge nozzle 48 is swirled in the loop pipe 40, and wet particles that are to be dried are continuously supplied to be accompanied by the swirling flow. While in contact with the dry gas, the moisture inside the wet particles moves to the gas and is discharged as dry particles with a reduced moisture content. The air dryer 14 has the above-described configuration, so that the wet particles are continuously dried.

  Examples of the air dryer 14 used in the drying system according to the present embodiment include an air dryer provided with the loop pipe 40 shown in FIGS. 1 and 2. The wet particles are dried with a gas, and the dried particles are used. If it has a structure discharged | emitted with gas, it will not specifically limit.

  Dry particles and gas discharged from the discharge port 44 of the air dryer 14 flow into the cyclone 16 through the transfer pipe 26. The dry particles and gas that have flowed into the cyclone 16 become a swirl flow (overflow) along the inner side wall, and descend along the side wall while swirling. The dried particles are collected in a collecting container 28 as a dried product of resin particles through a powder discharge pipe (not shown) provided at the lower end inside. On the other hand, the supplied gas descends inside together with the dry particles, and then becomes an air flow that rises in the center along the long axis of the cyclone 16 and is discharged from the gas discharge pipe 50. By being configured in this way, the cyclone 16 has a function of separating solid and gas. At this time, the humidity detecting means H1 detects the relative humidity Hout of the gas discharged from the gas discharge pipe 50 of the cyclone 16. The gas separated by the cyclone 16 is exhausted by the exhaust blower 32 after the fine powder is removed by the fine powder collecting bag filter 30.

  Examples of the recovery device according to the present embodiment include the cyclone 16 illustrated in FIG. 1, and a solid-gas separation device other than the cyclone 16 may be used.

  The drying system 10 according to the present embodiment includes temperature detection means T1 that detects the temperature Tin of the gas flowing into the air dryer 14. The temperature detecting means T1 may be provided at any position as long as it detects the temperature Tin of the gas flowing into the air dryer 14, for example, in the drying system 10 shown in FIG. Means T <b> 1 is provided in the gas supply unit 46 of the air dryer 14 and measures the temperature Tin of the dry gas flowing into the loop pipe 40 from the gas discharge nozzle 48. As the temperature detection means T1, a known temperature sensor that detects the temperature of the gas is used. For example, a temperature sensor such as a thermocouple or a radiation thermometer is used.

  The drying system 10 according to the present embodiment includes humidity detection means H1 that detects the relative humidity Hout of the gas discharged from the recovery device 16. The humidity detection unit H1 is provided in either the gas discharge pipe 50 of the recovery device 16 or a pipe connected to the gas discharge pipe 50, and measures the relative humidity Hout of the gas discharged from the recovery device 16. As the humidity detection means H1, a known humidity sensor that detects the temperature and relative humidity of the gas is used as the humidity detection means H1, for example, a humidity such as a polymer humidity sensor, a ceramic humidity sensor, and a thermal conductivity type humidity sensor. A sensor is used.

  The drying system 10 according to this embodiment adjusts the gas temperature control means for controlling the temperature of the gas flowing into the air flow dryer 14 to be equal to or lower than the glass transition temperature of the resin particles, and adjusts the supply amount of the resin particles to recover. Supply amount adjusting means for controlling the relative humidity of the gas discharged from the apparatus 16 to 45% RH or less.

  In general, a drying gas having a temperature exceeding the glass transition temperature Tg of the resin constituting the resin particles is used for the drying treatment of the resin particles in a wet state by the air dryer. However, when the temperature of the drying gas exceeds Tg, when the drying proceeds in the airflow dryer, the heat transferred from the drying gas cannot be consumed by the latent heat due to evaporation of moisture, the temperature of the resin particles rises, and the glass transition temperature Tg. May be exceeded. When the temperature of the resin particles exceeds Tg, the resin particles are aggregated by fusion and coarse powder is formed. If the content of the coarse particles in the collected dried resin particles is too large, the fluidity of the resin particles may be deteriorated. Particularly, when the resin particles are electrostatic charge image developing toner, the cause of image quality deterioration It may become. If the temperature of the resin particles exceeds Tg in the air dryer, the resin particles may be fused to the inner wall of the air dryer, and the drying process may be interrupted to clean the inner wall of the air dryer.

  Thus, in the airflow drying system 10 according to the present embodiment, the temperature Tin of the gas flowing into the airflow dryer 14 detected by the temperature detection means T1 is used for the drying process using the gas temperature control means. Control below the glass transition temperature Tg of the resin particles.

  The gas temperature control means included in the drying system 10 according to the present embodiment is any means as long as it is a means for controlling the temperature of the gas flowing into the air dryer 14 detected by the temperature detection means T1. May be. For example, a heater 24 for heating the dry gas, a discharge blower 22 and an exhaust blower 32 for adjusting the inflow amount and speed of the gas flowing into the air dryer 14 and the like can be mentioned. Since the control of the gas temperature is easy, the heater 24 is preferable as the gas temperature control means.

  In the present specification, “coarse powder” refers to an agglomerate of resin particles by heat fusion and does not pass through a standard sieve having an opening of 20 μm as defined in JIS Z8801-1: 2006. Further, in this specification, the “glass transition temperature Tg of resin particles” is the glass transition temperature Tg of the resin constituting the resin particles, and in accordance with ASTM D3418-8, the resin is measured using a differential scanning calorimeter. It is measured by performing differential scanning calorimetry (DSC) of the particles.

  Further, when the temperature of the dry gas flowing into the air dryer 14 becomes Tg or less, the moisture transfer rate from the wet particles to the dry gas decreases, and the moisture content of the dried resin particles recovered from the recovery device 16 It is possible that the rate will rise. When the moisture content of the dried resin particle product does not reach the target moisture content, additional drying treatment is required, which may increase the size of the drying apparatus or consume excessive energy. In particular, when the resin particle is an electrostatic image developing toner, developing an electrostatic image using a toner having a high moisture content may cause fogging of the image due to a decrease in charge. Necessary.

  Therefore, in the air flow drying system 10 according to the present embodiment, the relative amount of the gas discharged from the recovery device 16 detected by the humidity detecting unit H1 is adjusted by adjusting the supply amount of the resin particles using the supply amount adjusting unit. The humidity Hout is controlled to 45% RH or less. If the relative humidity Hout is 45% RH or less, the moisture moves from the wet particles to the gas in the loop pipe 40 of the air dryer 14, and the target is the dried resin particles recovered from the recovery device 16. A moisture content is achieved.

  The supply amount adjusting means included in the drying system according to the present embodiment may be any means as long as it is a means for adjusting the amount of wet particles supplied into the air dryer, for example, the raw material supply machine 12. For example, the supply amount of the wet particles is adjusted.

  The drying system 10 according to the present embodiment controls the temperature Tin of the gas flowing into the airflow dryer 14 to be equal to or lower than the glass transition temperature Tg of the resin particles by using the gas temperature control means, and the supply described above. By controlling the relative humidity Hout of the gas discharged from the recovery device 16 to 45% RH or less using the amount adjusting means, compared with the case where Tin exceeds the Tg of the resin particles, the recovered resin particles The content of coarse powder due to aggregation is reduced, and an increase in the moisture content is suppressed. As a result, the dried product of the resin particles obtained by the drying system 10 according to the present embodiment has an advantage that the quality is hardly deteriorated. In particular, when the resin particles are electrostatic charge image developing toners, Therefore, it is possible to obtain a toner that is stable and hardly deteriorates in image quality. Moreover, the drying system 10 which concerns on this embodiment suppresses melt | fusion of the resin particle to the inner wall of the air dryer 14, and the frequency which performs cleaning by interrupting the continuous operation of an air dryer is reduced.

  It is preferable that the relative humidity Hout of the gas discharged from the recovery device 16 controlled by the supply amount adjusting unit included in the drying system 10 according to the present embodiment is 45% RH or less and 10% RH or more. This is because when the supply amount of the wet particles is adjusted so that Hout is less than 10% RH, the processing capability of the airflow drying system may be lowered. Further, for example, it is conceivable that Hout is less than 10% RH by further improving the dehumidifying performance of the gas by the dehumidifier 20, but for that purpose, an increase in capital investment or power consumption may be required. is there.

  It is preferable to control the temperature Tin of the gas flowing into the air dryer 14 to Tg or less (Tg-30) (° C) or more by the gas temperature control means, and (Tg-2) (° C) or less (Tg-20). ) (° C.) or more is more preferable. When Tin is less than (Tg-30) (° C.), the evaporation rate of moisture decreases, and the moisture content of the powder particles recovered from the recovery device 16 may increase.

  In the drying system 10 shown in FIG. 1, it is preferable that air balance is taken so that the air blower 32 is sucked by the exhaust blower 32 through the cyclone 16 and the bag filter 30 so as to have a negative pressure inside the airflow drying device 10. . In order to control the pressure in the airflow drying device 10, for example, an outlet pressure Pmid in a pipe connected to the discharge port 44 of the airflow drying device 10 is measured by an outlet pressure gauge (not shown).

<Drying method>
The resin particle drying method according to the present embodiment (hereinafter also referred to as “drying method”) includes a resin particle supply step of supplying resin particles from a raw material supplier to an air flow dryer that dries the resin particles with gas, and the supplied resin The temperature of the gas flowing into the air dryer includes at least a drying step of drying the particles using the air dryer and a recovery step of recovering the resin particles dried by the air dryer using a recovery device. Is controlled below the glass transition temperature of the resin particles, and the relative humidity of the gas discharged from the recovery device is controlled below 45% RH.

  The drying method according to this embodiment will be described with reference to the drying system 10 shown in FIG. 1 and the air flow dryer 14 shown in FIG. 2, but the drying method according to this embodiment is in the mode shown in FIG. 1 and FIG. It is not limited.

  In the drying method according to the present embodiment, a resin particle supply process is performed in which resin particles (wet particles) in a wet state are supplied from the raw material supply machine 12 to the air flow dryer 14. Thereafter, in the air dryer 14, the dry gas supplied from the gas discharge nozzle 48 is swirled in the loop pipe 40, and wet particles are continuously supplied to be accompanied by the swirl flow, and the moisture inside the wet particles is turned into a dry gas. By moving it, the drying process of the wet particles using the air dryer 14 is performed. At this time, the temperature Tin of the dry gas flowing into the air dryer 14 is measured by the temperature detecting means T1 shown in FIG.

  The resin particles (dried particles) dried by the air dryer 14 are discharged together with the gas to a cyclone 16 as a recovery device, and the dry particles and the gas are separated into a solid and gas in the cyclone 16, thereby drying using the recovery device. A particle recovery step is performed. At this time, the relative humidity Hout of the gas discharged from the gas discharge pipe 50 of the cyclone 16 is measured by the humidity detecting means H1 shown in FIG.

  In the drying method according to the present embodiment, the temperature Tin of the gas flowing into the air dryer 14 is controlled to be equal to or lower than the glass transition temperature Tg of the resin particles. As a means for controlling the Tin, the temperature of the Tin in the drying system 10 such as the heater 24, the discharge blower 22 and the exhaust blower 32 for adjusting the inflow amount and speed of the gas flowing into the air dryer 14 is varied. Any means may be used as long as it is used, but the heater 24 is preferable because the temperature of the gas is easy to control.

  In the drying method according to the present embodiment, the relative humidity Hout of the gas discharged from the recovery device 16 is controlled to 45% RH or less. As a means for controlling Hout, in addition to the supply amount adjusting means in the drying system 10 such as the raw material supplier 12, the dehumidifier 20 for dehumidifying the gas flowing into the airflow dryer 14, and the gas flowing into the airflow dryer 14 Any means may be used as long as Hout is varied, such as the discharge blower 22 and the exhaust blower 32 that adjust the inflow amount of the gas, but the raw material feeder 12 is preferable because the adjustment is easy.

  In the drying method according to the present embodiment, the temperature Tin of the gas flowing into the air dryer is controlled to be equal to or lower than the glass transition temperature Tg of the resin particles to be dried, and the relative humidity of the gas discharged from the recovery device is 45% RH. By controlling to the following, compared with the case where Tin exceeds Tg of the resin particles, the content of the coarse powder due to the aggregation of the resin particles of the recovered resin particles is reduced, and the increase in the moisture content is suppressed. Is done. The dried product of the resin particles obtained by the drying method according to the present embodiment has an advantage that the quality is hardly deteriorated. In particular, when the resin particles are an electrostatic charge image developing toner, the product is continuously and stably. There is an advantage that a toner that hardly deteriorates the image quality can be obtained. Moreover, the frequency of performing cleaning by suppressing the fusion of the resin particles to the inner wall of the air dryer and interrupting the continuous operation of the air dryer is reduced.

<Resin particles>
The resin particles to be dried by the drying system and drying method of the present embodiment are not particularly limited, and are produced, for example, by an electrostatic charge image developing toner (hereinafter also referred to as “toner”), particularly by a wet method. Toner. Since the toner in the wet state is likely to be fused in the dryer, the drying system and the drying method according to this embodiment are preferably used for drying the wet toner.

  Examples of the solvent contained in the wet particles dried by the drying system and the drying method of this embodiment include organic solvents such as water and alcohol. When the wet particles are wet toners produced by a wet process, they usually contain water. The gas used in the drying system and drying method of the present embodiment is usually air, but an inert gas such as nitrogen gas may be used.

<Toner for electrostatic image development>
The case where an electrostatic charge image developing toner is used as the resin particles dried by the drying system and drying method of the present embodiment will be described. However, the resin particles dried by the drying system and drying method of the present embodiment are not limited to toner.

  The toner for developing an electrostatic image may be produced by a wet method such as a suspension polymerization method, an emulsion polymerization aggregation method, or a dispersion polymerization method, or may be produced by another method. The toner produced by these methods becomes a toner after a solid-liquid separation and a drying process for drying the water-containing cake. Hereinafter, a toner obtained by an emulsion polymerization aggregation method which is one of wet methods will be described as an example.

  In the toner by the emulsion polymerization aggregation method, a resin particle dispersion prepared by emulsion polymerization or the like and a colorant particle dispersion are mixed, and after adding an aggregating agent to agglomerate the toner particle size, the temperature exceeds the glass transition point of the resin. In this method, toner particles are produced by heating and fusing the aggregates.

  The resin used for the resin particles of the toner is not particularly limited. Specifically, styrenes such as styrene, parachlorostyrene, and α-methylstyrene; acrylics such as methyl acrylate, ethyl acrylate, n-propyl acrylate, butyl acrylate, lauryl acrylate, and 2-ethylhexyl acrylate Monomers: methacrylic monomers such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate; ethylene such as acrylic acid, methacrylic acid, sodium styrenesulfonate Unsaturated acid monomers; vinyl nitriles such as acrylonitrile and methacrylonitrile; vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl such as vinyl methyl ketone, vinyl ethyl ketone, and vinyl isopropenyl ketone Tons; homopolymers of monomers such as olefin monomers such as ethylene, propylene and butadiene, copolymers of combinations of two or more of these monomers, or mixtures thereof, and epoxy resins Polyester resin, polyurethane resin, polyamide resin, cellulose resin, polyether resin, etc., non-vinyl condensation resin, or a mixture of them with the vinyl resin, and polymerizing vinyl monomers in the presence of these resins. The obtained graft polymer etc. are mentioned.

  The resin particle dispersion is obtained by emulsion polymerization or a polymerization method in a similar dispersion system. In addition, a polymer polymerized in advance by a solution polymerization method or a bulk polymerization method is stabilized in a solvent in which the polymer does not dissolve. It is obtained by a method such as a method of adding together with an agent and mixing and dispersing mechanically. For example, when a vinyl monomer is used, an ionic surfactant or the like is used, preferably an ionic surfactant and a nonionic surfactant are used in combination, and the resin particles are obtained by emulsion polymerization or seed polymerization. What is necessary is just to produce a dispersion liquid.

  The surfactant used here is an anionic surfactant such as sulfate ester, sulfonate, phosphate, or soap; a cationic surfactant such as amine salt or quaternary ammonium salt; polyethylene Nonionic surfactants such as glycols, alkylphenol ethylene oxide adducts, alkyl alcohol ethylene oxide adducts, polyhydric alcohols, and various graft polymers are exemplified, but not particularly limited. .

  When preparing a resin particle dispersion by emulsion polymerization, a small amount of unsaturated acid, for example, acrylic acid, methacrylic acid, maleic acid, styrene sulfonic acid, etc. is added as a monomer component to form a protective colloid layer on the particle surface. It is preferable to form soap-free polymerization. Even in a polymerization method other than the emulsion polymerization method, it is assumed that the particle size of the resin particles is basically smaller than the target particle size at the end of aggregation (corresponding to the toner particle size).

  As release agent particles, low molecular weight polyolefins such as polyethylene, polypropylene and polybutene; silicones; fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide and stearic acid amide; carnauba wax, rice wax, Plant waxes such as candelilla wax, tree wax, jojoba oil; animal waxes such as beeswax; mineral or petroleum waxes such as montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropsch wax; and Examples thereof include modified products thereof.

  These waxes are dispersed in water together with polymer electrolytes such as ionic surfactants, polymer acids, and polymer bases, and heated above their melting point, and are homogenizers and pressure discharge type dispersers that give strong shearing force. It is sufficient that a dispersion liquid of particles having a size of 1 μm or less is prepared by forming into particles using. These release agent resin particles may be added to the mixed solvent at the same time as other resin particle components, or may be added separately.

  Examples of the colorant include carbon black, chrome yellow, hansa yellow, benzidine yellow, selenium yellow, quinoline yellow, permanent orange GTR, pyrazolone orange, vulcan orange, watch young red, permanent red, brillianthamine 3B, brillianthamine 6B, Dipon oil red, pyrazolone red, risor red, rhodamine B rake, lake red C, rose bengal, aniline blue, ultramarine blue, calco oil blue, methylene blue chloride, phthalocyanine blue, phthalocyanine green, malachite green oxalate, etc. Pigment, acridine, xanthene, azo, benzoquinone, azine, anthraquinone, thioindico Dioxazine, thiazine, azomethine, indigo dyes, phthalocyanine, aniline black, polymethine, triphenylmethane dyes, diphenylmethane dyes, various dyes such as thiazole, is used alone or in combination.

  These dispersing methods are performed by, for example, a rotary shear type homogenizer, a ball mill having media, a sand mill, a dyno mill, or the like, and the dispersing method is not limited at all.

  When toner is used as the magnetic toner, magnetic powder may be contained in the toner. Examples of the magnetic powder include metals such as ferrite, magnetite, reduced iron, cobalt, nickel, and manganese, alloys, and compounds containing these metals. Further, various charge control agents that are usually used, such as quaternary ammonium salts, nigrosine compounds and triphenylmethane pigments, may be added as necessary.

  As the aggregating agent, a surfactant having a polarity opposite to that of the surfactant used in the resin particle dispersion or the colored particle dispersion, a divalent or higher-valent inorganic metal salt, a metal complex, or the like is preferably used. In particular, the use of an inorganic metal salt or a metal complex is preferable because the amount of the surfactant used is reduced and the charging characteristics are improved.

  These inorganic metal salts or metal complexes include, for example, metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, aluminum sulfate, polyaluminum chloride, polyaluminum hydroxide, Examples thereof include inorganic metal salt polymers such as calcium sulfide. Aluminum salts and polymers thereof are preferred. In order to obtain a sharper particle size distribution, a compound having a large valence of a metal atom in an inorganic metal salt is preferred, and an inorganic metal salt polymer is more preferred when the valence is equal.

  By subjecting these raw materials to an aggregation and coalescence process, colored toner particles and the like can be obtained. Next, the water-containing cake that is a solid matter of the colored particles is filtered from the dispersion liquid of the colored toner particles obtained in the above-mentioned step in the washing step, and deposits such as surfactants and impurities are removed from the filtered water-containing cake. The cleaning process to remove is performed. The wet toner obtained in the washing step is a water-containing cake or a water-containing slurry, and the water content is usually 10% by mass or more and 50% by mass or less. For example, the wet toner obtained as described above is subjected to a drying process by the drying system according to the present embodiment.

  In the exemplary embodiment, when the resin particles to be dried are toner, the glass transition temperature Tg of the toner is more preferably 40 ° C. or higher and 70 ° C. or lower. This is because when the Tg of the toner is included in the above range, it is easy to control the amount of water during drying. In particular, when the drying system according to this embodiment is used for drying processing of toner having a Tg of 65 ° C. or lower, which is suitable for use in fixing at a lower temperature than the conventional fixing temperature, the Tg exceeds 65 ° C. For the toner, deterioration of quality due to heat and fusion in the dryer are suppressed.

  In the present embodiment, when the resin particles to be dried are toner, the moisture content of the dry toner recovered from the recovery device 16 is preferably 1.5% by mass or less, and more preferably 1.2% by mass or less. preferable. This is because if the moisture content of the dry toner exceeds 1.5% by mass, the image may be fogged due to a decrease in charge.

  Preferred drying conditions in the case where a wet toner is used as the resin particles to be dried are shown below.

As a drying condition of the air dryer 14 of the present embodiment, the discharge speed of the gas discharge nozzle 48 is preferably 50 m / s or more and 250 m / s or less. The discharge speed of the gas discharge nozzle 48 described here is:
Discharge speed [m / s] = gas inflow amount to drying apparatus [m ³ / min] / number of airflow nozzles / nozzle cross-sectional area per one [m ² ] / 60 [s / min]
Is calculated by When the air flow discharge speed is 50 m / s or less, the toner is discharged from the discharge port 44 with insufficient crushing and dispersion of the toner, and the moisture content of the obtained dry toner may increase. When the airflow discharge speed is 250 m / s or more, a large stress is applied to the toner in the airflow dryer 14, which may cause destruction or loss of the toner. The discharge speed of the gas discharge nozzle 48 is controlled by the discharge blower 22 and the exhaust blower 32.

  The exhaust pressure of the exhaust blower 32 is, for example, such that the gas pressure Pmid at the discharge port 44 of the air dryer 14 is −25 kPa to −1 kPa, more preferably −20 kPa to −5 kPa with respect to atmospheric pressure. It is preferable to adjust. When Pmid is on the positive pressure side with respect to atmospheric pressure from −1 kPa, the raw material may blow out from the raw material supply port 42. Further, when Pmid is on the negative pressure side with respect to atmospheric pressure from −25 kPa, the load on the apparatus becomes large, and capital investment may be required.

  Hereinafter, based on an Example, embodiment of this invention is described more concretely. In the following examples, unless otherwise specified, “%” represents “mass%” and “part” represents “part by mass”. In addition, this invention is not limited to the following Example.

[Measuring method]
The glass transition temperature (Tg) of the binder resin of the resin particles is determined by differential scanning calorimetry in accordance with ASTM D3418-8, and 1 using a differential scanning calorimeter (manufactured by Shimadzu Corporation, DSC-50). The temperature at the intersection of the extension line of the base line and the rising line in the endothermic part of the DSC curve obtained in the second temperature raising process was defined as the glass transition temperature.

  The weight average molecular weight (Mw) was measured using gel permeation chromatography (manufactured by Tosoh Corporation, HLC-8120).

  The moisture content (% by mass) of the wet toner as the raw material to be dried, the sample taken out from the discharge port 44, and the dry toner was measured by an electronic moisture meter (MA30, manufactured by Zaritrius Co.) by a heat loss method at 120 ° C. .

  As for the coarse powder amount of the dry toner collected in the collecting device 16, the collected dry toner is sieved using a standard sieve having an opening of 20 μm defined in JIS Z8801-1: 2006, and the collected toner is collected. The weight ratio of the toner that does not pass through the sieve to the total amount of was the amount of coarse powder (mass%).

[Synthesis of resin]
<Synthesis of Amorphous Resin A>
4,690 parts of bisphenol A propylene oxide adduct, 1,370 parts of bisphenol A ethylene oxide adduct, 1,520 parts of terephthalic acid, 750 parts of fumaric acid, and 1,140 parts of dodecenyl succinic acid were added to a stirrer, thermometer, The reaction vessel equipped with a condenser and a nitrogen gas inlet tube was charged. Thereafter, 40 parts of dibutyltin oxide was added as a catalyst. Nitrogen gas was introduced into the container to maintain an inert atmosphere, and the copolycondensation reaction was performed for 12 hours while maintaining the temperature in the container at 150 ° C. or higher and 230 ° C. or lower. Thereafter, the pressure was gradually reduced at a temperature of 210 ° C. or higher and 250 ° C. or lower to synthesize amorphous polyester resin A. The obtained amorphous resin A had a weight average molecular weight (Mw) of 50,000. Moreover, the acid value of the amorphous resin A was 12.4 mgKOH / g.

<Synthesis of crystalline resin B>
A monomer component consisting of 50 mol% of 1,10-dodecanedioic acid and 50 mol% of 1,9-nonanediol was placed in a reaction vessel equipped with a stirrer, a thermometer, a condenser and a nitrogen gas inlet tube. After replacing the inside of the reaction vessel with dry nitrogen gas, 2.5 parts of titanium tetrabutoxide (reagent) was added to 1,000 parts of the monomer component and stirred at 170 ° C. for 3 hours under a nitrogen gas stream. It was made to react. Furthermore, the temperature was raised to 210 ° C., the pressure in the reaction vessel was reduced to 3 kPa, and the reaction was carried out with stirring for 13 hours under reduced pressure to synthesize crystalline resin B. The obtained crystalline resin B had a weight average molecular weight (Mw) of 25,000. The acid value of the crystalline resin B was 11.4 mgKOH / g.

[Production of resin particles]
<Preparation of Amorphous Resin Particle Dispersion A1>
In an emulsification tank of a wet emulsification disperser (Caitron CD1010, slit: 0.4 mm, manufactured by Taiyo Kiko Co., Ltd.), 1,500 parts of amorphous resin A, 1,670 parts of ethyl acetate, an anionic surfactant ( 25 parts of sodium dodecylbenzene sulfonate) and 2,500 parts of ion-exchanged water were added. The obtained emulsified liquid was heated to 50 ° C. and dispersed in an emulsifying apparatus at 10,000 rpm for 30 minutes. Then, ethyl acetate was distilled off to produce an amorphous resin particle dispersion A1 having a volume average particle diameter D50v of 180 nm. Thereafter, ion exchange water was added to adjust the solid content concentration to 35.0%.

<Preparation of crystalline resin particle dispersion B1>
In an emulsification tank of a wet emulsification disperser (Daihei Kiko Co., Ltd., Cavitron CD1010, slit: 0.4 mm), 2,200 parts of crystalline resin B, 2,200 parts of ethyl acetate, 10 parts of aqueous sodium hydroxide, 250 parts of an anionic surfactant (sodium dodecylbenzene sulfonate) and 4,000 parts of ion-exchanged water were added. The obtained emulsified liquid was heated to 60 ° C. and dispersed in an emulsifying apparatus at 10,000 rpm for 30 minutes. Then, ethyl acetate was distilled off to produce a crystalline resin particle dispersion B1 having a volume average particle diameter D50v of 160 nm. Thereafter, ion exchange water was added to adjust the solid content concentration to 40.0%.

<Preparation of release agent dispersion>
Release agent (Nippon Seiki Co., Ltd., trade name: FNP0090, paraffin wax, melting point Tw 89.7 ° C.) 270 parts, anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., trade name: Neogen RK, active ingredient) (Amount: 60%) 13.5 parts (3.0% with respect to the release agent as an active ingredient) and 721.6 parts of ion-exchanged water were mixed. Using a pressure discharge type homogenizer (Gorin homogenizer manufactured by Gorin Co., Ltd.), the release agent was dissolved under the condition that the temperature of the mixed solution (inner solution) was 120 ° C. Thereafter, a dispersion treatment was performed at a dispersion pressure of 5 MPa for 120 minutes, and subsequently at a dispersion pressure of 40 MPa for 360 minutes, followed by cooling to obtain a release agent dispersion. The volume average particle diameter D50v of the particles in the release agent dispersion is 230 nm. Thereafter, ion exchange water was added to adjust the solid content concentration to 20.0% to obtain a release agent dispersion.

<Preparation of colorant dispersion>
Cyan pigment (Daiichi Seika Kogyo Co., Ltd., ECB301) 200 parts, anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen SC, active ingredient amount: 60%) 33 parts (as an active ingredient, colorant) 10%) and when 750 parts of ion-exchanged water were added, a stainless steel container having a liquid level height of about 1/3 of the container height was prepared. After putting 280 parts of ion-exchanged water and 33 parts of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen SC, active ingredient amount: 60%) into the stainless steel container, and sufficiently dissolving the surfactant Then, 200 parts of a cyan pigment (manufactured by Dainichi Seika Kogyo Co., Ltd., ECB301) was put into a stainless steel container.

  The mixture was stirred using a stirrer until the wet pigment disappeared and sufficiently defoamed. Thereafter, 470 parts of ion-exchanged water is added to the container, and the mixture is dispersed for 10 minutes at 5,000 rpm using an homogenizer (manufactured by IKA, Ultra Tarrax T50). did. Then, after using a homogenizer again to disperse at 6,000 rpm for 10 minutes, the mixture was stirred for one day with a stirrer for defoaming.

  Subsequently, the obtained dispersion was subjected to a dispersion treatment under the condition of a pressure of 240 MPa using a high-pressure impact disperser ultimateizer (manufactured by Sugino Machine Co., Ltd., HJP30006). Dispersion by the optimizer was equivalent to 25 passes in terms of the total charge and the processing capacity of the apparatus. The obtained dispersion was allowed to stand for 72 hours to remove precipitates, and then ion-exchanged water was added to adjust the solid content concentration to 15% to obtain a colorant dispersion. The volume average particle diameter D50v of the particles in this colorant dispersion is 115 nm.

<Preparation of flocculant aqueous solution>
35 parts of aluminum sulfate (Asada Chemical Industry Co., Ltd., 17% aluminum sulfate) and 1,965 parts of ion-exchanged water are put into a container, and stirred and mixed at 30 ° C. until the precipitate disappears. Obtained.

<Manufacture of wet toner>
90 parts of crystalline resin dispersion B1, 635 parts of amorphous resin particle dispersion A1, 150 parts of colorant dispersion, 160 parts of release agent dispersion, 1,300 parts of ion-exchanged water, anionic 40 parts of a surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neogen S20F) was placed in a reaction vessel equipped with a thermometer, pH meter, stirrer, and temperature control equipment. The obtained mixed liquid was treated at a temperature of 25 ° C. using a wet emulsification disperser (manufactured by Taihei Koki Co., Ltd., Cavitron CD1010, slit: 0.4 mm) under the condition of 10,000 rotations / minute. While adding 125 parts of an aqueous solution, the mixture was dispersed for 6 minutes.

  While adjusting the rotation speed of the stirrer so that the slurry was sufficiently stirred, the temperature of the slurry was increased at 0.1 ° C./min up to 40 ° C. The particle size of the slurry was measured every 10 minutes with Multisizer II (Beckman-Coulter, aperture diameter: 50 μm), and when the volume average particle size D50v reached 5.0 μm, the temperature increase was stopped. The temperature was maintained. Next, 150 parts of the amorphous resin dispersion A1 was charged into the slurry over 5 minutes. After holding the slurry for 30 minutes, the pH was adjusted to 9.0 using 4% aqueous sodium hydroxide. Thereafter, while adjusting the pH to 9.0 every 5 ° C., the temperature of the slurry was increased to 90 ° C. at a temperature rising rate of 1 ° C./min, and kept at 90 ° C.

  When the shape and surface properties of the particles in the slurry were observed every 15 minutes using an optical microscope and a scanning electron microscope (FE-SEM), the coalescence of the particles was 1.0 hour after the start of holding at 90 ° C. As confirmed, the slurry was cooled to 30 ° C. over 5 minutes using a heat exchanger. The slurry after cooling was passed through a nylon mesh having an opening of 15 μm to remove coarse powder. Then, the solid-liquid separation process and the pressing process of the slurry were performed using the filter press (made by Kurita Machinery Co., Ltd.). Subsequently, ion exchange water as a cleaning liquid is injected through the cleaning liquid piping of the filter press, and the toner is cleaned until the conductivity value of the filtrate measured by a conductivity meter installed in the filtering piping of the filter press is 30 μS / cm or less. did. The washed toner was finely crushed with a wet dry granulator (Comil) to obtain a wet toner having a moisture content of 35%. The obtained toner had a glass transition temperature Tg of 60 ° C.

[Drying test]
Example 1
Using the wet toner obtained above as a raw material, a drying test was conducted using the airflow drying system described in FIG. In the drying test of Example 1, the temperature of the gas flowing into the air dryer 14 detected by the temperature detecting means T1 is adjusted to 55 ° C., and the amount of gas flowing into the air dryer 14 is set to 2 m ³ / The supply amount of wet toner was adjusted to 2.0 kg (2.0 kg / h) per hour. The heater 24 was used to adjust the temperature of the gas flowing into the air dryer 14. The supply amount of the wet toner was adjusted by the raw material supply machine 12. The relative humidity of the gas discharged from the gas discharge pipe 50 of the cyclone 12 at this time was 30% RH when detected by the humidity detecting means H1. With respect to the dry toner collected from the cyclone 16, the moisture content (water content after drying) (mass%) and the amount of coarse powder (mass%) were measured. Table 1 shows these measured values and drying test conditions in the drying test of Example 1.

(Example 2)
In the drying test, the same as Example 1 except that the supply amount of the wet toner is adjusted to 1.0 kg / h by the raw material supplier 12 and the relative humidity detected by the humidity detection means H1 is 15% RH. A drying test was conducted under the conditions. The measured values of the moisture content and the amount of coarse powder in the drying test of Example 2 are shown in Table 1 together with the drying test conditions.

Example 3
In the drying test, the same conditions as in Example 1 were used except that the supply amount of wet toner was adjusted to 5 kg / h by the raw material supplier 12 and the relative humidity detected by the humidity detection means H1 was 43% RH. A drying test was performed. The measured values of the moisture content and the amount of coarse powder in the drying test of Example 3 are shown in Table 1 together with the drying test conditions.

Example 4
In the drying test, the drying test was performed under the same conditions as in Example 1 except that the temperature of the drying gas flowing into the airflow dryer 14 was adjusted to 60 ° C. using the heater 24. Table 1 shows the measured values of the moisture content and the amount of coarse powder in the drying test of Example 4 together with the drying test conditions.

(Comparative Example 1)
In the drying test, the same conditions as in Example 1 were used except that the supply amount of wet toner was adjusted to 7 kg / h by the raw material supplier 12 and the relative humidity detected by the humidity detection means H1 was 55% RH. A drying test was performed. Table 1 shows the measured values of the moisture content and the amount of coarse powder in the drying test of Comparative Example 1 together with the drying test conditions.

(Comparative Example 2)
In the drying test, the drying test was performed under the same conditions as in Example 1 except that the temperature of the drying gas flowing into the airflow dryer 14 was adjusted to 65 ° C. using the heater 24. Table 1 shows the measured values of the moisture content and the amount of coarse powder in the drying test of Comparative Example 2 together with the drying test conditions.

  As the results of Examples 1 to 4 show, the raw material supplier 12, the air dryer 14, the recovery device 16, the temperature detector T1, the humidity detector H1, and the gas flowing into the air dryer 14 Gas temperature control means for controlling the temperature Tin of the resin particles below the glass transition temperature Tg of the resin particles, and adjusting the supply amount of the resin particles to control the relative humidity Hout of the gas discharged from the recovery device 16 to 45% RH or less Compared with the case where the temperature Tin of the gas flowing into the air dryer 14 exceeds the glass transition temperature Tg of the resin particles, by using the air flow drying system having the supply amount adjusting means, the coarseness due to the aggregation of the resin particles. The powder content was reduced, and an increase in the moisture content of the recovered resin particles was suppressed.

DESCRIPTION OF SYMBOLS 10 Airflow drying system, 12 Raw material supply machine, 14 Airflow dryer, 16 Recovery apparatus (cyclone), 20 Dehumidifier, 22 Discharge blower, 24 Heater, 26 Transfer piping, 28 Recovery container, 30 Bag filter, 32 Exhaust blower, 40 Loop piping, 42 Raw material supply port, 44 discharge port, 46 gas supply unit, 48 gas discharge nozzle, 50 gas discharge pipe, H1 humidity detection means, T1 temperature detection means.

Claims (2)

  A raw material supplier for supplying resin particles, an air dryer for drying resin particles with gas, a recovery device for recovering resin particles dried by the air dryer, and a temperature of gas flowing into the air dryer Temperature detecting means for detecting, humidity detecting means for detecting the relative humidity of the gas discharged from the recovery device, and gas temperature control for controlling the temperature of the gas flowing into the air dryer to be equal to or lower than the glass transition temperature of the resin particles And a supply amount adjusting means for adjusting the supply amount of the resin particles to control the relative humidity of the gas discharged from the recovery device to 45% RH or less. A resin particle supplying step of supplying resin particles from a raw material supply machine to an airflow dryer for drying resin particles by gas, a drying step of drying the supplied resin particles using the airflow dryer, and the airflow dryer. A recovery step of recovering the dried resin particles using a recovery device, the temperature of the gas flowing into the air dryer is controlled to be equal to or lower than the glass transition temperature of the resin particles, and discharged from the recovery device A method for drying resin particles, wherein the relative humidity of the gas is controlled to 45% RH or less.

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