JP3781151B2 - Method for producing powder slurry paint - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a powder slurry paint (including an ultraviolet curable powder slurry paint, hereinafter the same sentence) used in the technical field of paints and the like.
[0002]
[Prior art]
Conventionally, there are a wet method and a dry method as a method for producing a powder paint or the like.
In the wet method, a paint is made in almost the same way as a normal solvent-type paint, and then the solvent is distilled off and pulverized, or after being dispersed in a large amount of non-solvent, filtered and dried, or heated. A method of removing the solvent by spraying in the air is performed. However, there are many technical problems and the cost is higher than that of the dry method at present, so it is not put into practical use.
[0003]
In addition, the dry method includes various steps of mixing, heating and melting, kneading various materials, and further cooling, pulverizing and classifying. Further development is possible in the future as a paint that does not use organic solvents.
[0004]
However, the following problems are listed in the dry method.
1) The shape of the powder coating must be indefinite, and the fluidity as a powder is extremely deteriorated particularly in the case of a powder coating having a volume average diameter of 20 microns or less.
[0005]
2) The smaller the powder has a smaller particle size, the more the pulverization energy required per powder weight increases dramatically, resulting in higher costs. As a trend of powder coatings in recent years, the average particle size of powder coatings is becoming smaller due to the demand for surface smoothness and glossiness, and the appearance of ultrafine powder coatings of 10 microns or less will appear in the near future. However, it is very difficult to manufacture the powder coating material by the conventional pulverization method, and even if it is possible, the cost is high.
[0006]
3) Among the powder paints, the ultraviolet curable powder paint has a softening point of 60 to 120 ° C. lower than that of a normal powder paint. Therefore, it is indispensable to treat the powder so as not to be fused with each other in the pulverization process when manufacturing the ultraviolet curable powder coating material.
[0007]
It is very difficult to overcome the above problems by the conventional wet method and dry method.
The powder slurry paint of the present invention is produced by emulsifying and dispersing the powder paint obtained above in an aqueous medium.
[0008]
[Problems to be solved by the invention]
An object of the present invention is to provide a method for producing a powder slurry paint that drastically improves the conventional method and solves the problems.
[0009]
Specifically, (1) The present invention provides a method for producing a powder slurry paint that does not require a pulverization step in a dry process.
[0010]
{Circle around (2)} The present invention provides a simple and highly productive continuous production method that can easily produce an ultrafine powder coating of 10 microns or less.
{Circle around (3)} The present invention provides a production method that makes it easy to produce an ultraviolet curable powder coating material that does not require a pulverization step and is difficult to pulverize and has a low softening point.
[0011]
(4) Providing a manufacturing method that does not require equipment like a powder coating line and can be introduced with little modification if it is an existing water-based coating line.
[0012]
[Means for Solving the Problems]
The inventors of the present invention have repeatedly conducted intensive trial studies on whether or not a powder paint having both the merit of a dry method using no organic solvent and the advantage of a spherical powder and a fine powder paint of a wet method can be obtained. It has been found that the above-mentioned problems can be achieved through a step of mechanically emulsifying and dispersing with an emulsifying and dispersing machine, and the present invention has been achieved.
[0013]
That is, the present invention includes (1) a resin melt (a) obtained by heating and melting a kneaded product of a synthetic resin for powder coating, a curing agent and / or a photoinitiator, and a softening point of the synthetic resin ± 30. (2) While maintaining the temperature of the mixture at the softening point of the synthetic resin ± 30 ° C., the resin melt (a) is mixed in the aqueous medium (b). (3) A method for producing a powder slurry paint characterized in that it is rapidly cooled immediately thereafter.
[0014]
As a mechanical means for emulsification and dispersion, a ring-shaped stator having a slit and a ring-shaped rotor having a slit are coaxially arranged so that the stator and the rotor are engaged with each other while maintaining a slight gap. Is a method for producing a powder slurry paint using a high-speed rotation type continuous emulsification disperser provided in the method, comprising: a synthetic resin for powder paint, a curing agent and / or a photoinitiator, and, if necessary, a color pigment. A mixture of a resin melt formed by heating and melting the kneaded material and an aqueous medium is supplied to the high-speed rotation type continuous emulsification disperser, and the mixture is separated from the slit and the gap by high-speed rotation of the rotor. Through the rotor from the inner center of the rotor in a centrifugal direction, applying shearing force while passing through the stator slit and the rotor slit, and the mixture passes through the gap between the stator and the rotor Apply shear stress during By, the resin melt which is a method of producing a powder slurry coating material emulsified and dispersed in an aqueous medium.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention is a method for producing a powder slurry coating comprising an aqueous dispersion by mechanically emulsifying and dispersing resin fine particles in an aqueous medium without using a solvent (hereinafter referred to as an aqueous emulsion dispersion method). It goes through.
[0016]
First, the first step of the present invention will be described.
That is, a resin melt (a) obtained by heating and melting a kneaded product of a synthetic resin for powder coating, a curing agent and / or a photoinitiator, and, if necessary, a color pigment, and a dispersant or It is a step of mixing the aqueous medium (b) containing a surfactant, heated and further pressurized as necessary to a temperature around the softening point of the synthetic resin.
[0017]
The synthetic resin for powder coating used in this process may be any material as long as it is suitable for the powder coating. Examples thereof include acrylic resins, epoxy resins, amine-modified resins, phenol resins, xylene resins, polyester resins, urea resins, urethane resins, blocked isocyanate resins, and mixtures thereof. Among these, a combination of an unsaturated polyester resin and urethane acrylate or urethanized vinyl ether is particularly suitable as an ultraviolet curable powder coating resin, and an acrylic resin, a polyester resin, or an epoxy is used as a normal powder coating resin. A resin or the like is preferable.
[0018]
Any curing agent and photoinitiator may be used as long as they are suitable for powder coatings. Examples of the curing agent include polycarboxylic acids (such as dodecanedioic acid and trimellitic acid), amino resins, block polyisocyanates, polyepoxides, polyols, and the like. Examples of the photoinitiator include acetophenone, benzophenone, Michler ketone, benzyl, benzoin, benzoin isobutyl ether, benzyl dimethyl ketal (Irgacure-651), 1-hydroxycyclohexyl phenyl ketone (Irgacure-184), 2-hydroxy-2-dimethyl. -1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, azobisisobutylnitrile, benzoyl peroxide, di-tert-butyl peroxide, etc. Can be mentioned.
[0019]
Depending on the type of synthetic resin, the curing agent and photoinitiator may be used in combination when used alone.
In addition to a curing agent and a photoinitiator, a colored pigment can be added to the synthetic resin as necessary. Examples of the color pigment include organic pigments and inorganic pigments. Examples of organic pigments include azo pigments, phthalocyanine pigments, condensed polycyclic pigments, nitroso pigments, and the like, and inorganic pigments include, for example, oxide pigments, phthalocyanine compounds, and chromate salts. Pigments, carbon pigments, mica pigments, metal powder pigments and the like. These pigments may be coated with a pigment dispersant.
[0020]
In addition, a filler, a rust preventive agent, a UV stabilizer, a UV absorber, a flow regulator, a repellency inhibitor, and the like are blended as additives.
The above raw materials are kneaded and melted by heating to produce a resin melt. A known method is used to produce this resin melt. Specifically, if it does not contain a curing agent, after synthetic blending, photoinitiator, and if necessary, color pigments and additives are dry blended with a mixer, they are completely melted in a heating and melting tank equipped with a stirrer. Sent to the melt tank. If it contains a curing agent, dry blend the synthetic resin, curing agent and, if necessary, photoinitiator, coloring pigment, and additives with a mixer, then send to a screw mixer, and heat, melt, and knead with an extruder. Then, this kneaded product is fed directly to the following rotary continuous emulsifying disperser.
[0021]
Next, the aqueous medium of the present invention will be described. In general, the aqueous medium is basically water, and a dispersant and a surfactant may be added as necessary in order to form an aqueous dispersion of a stable resin melt. The dispersant is not particularly limited. For example, water-soluble polymer dispersion stabilizers such as polyvinyl alcohol and hydroxyethyl cellulose, which are often used in suspension polymerization such as styrene, or poorly water-soluble inorganic dispersions such as calcium phosphate. A stabilizer etc. are mentioned, What is necessary is just to use a suitable thing from these. The surfactant is not particularly limited, and examples thereof include 2,6,8-trimethyl-4-nonyloxypolyethyleneoxyethanol.
[0022]
The ratio of the aqueous medium to the synthetic resin needs to be an amount sufficient to make an aqueous emulsion dispersion.
The solventless aqueous emulsion dispersion method of the present invention is characterized in that the synthetic resin melt and the aqueous medium are heated to a temperature around the softening point of the resin. The temperature before and after the softening point is not particularly limited, but is preferably within ± 30 ° C. in order to maintain the synthetic resin in a molten state.
[0023]
The aqueous medium is a high-temperature aqueous medium that is heated and pressurized as necessary. By using a heat exchanger or the like for heating, the synthetic resin for powder coating is heated to a temperature around the softening point of the synthetic resin in order to melt it. Therefore, the aqueous medium, the softening point of the synthetic resin used, pressured by 1Kg / cm ² ~20Kg / cm ² of about pressurizing means provided in the process, is adjusted to proper temperature. In particular, when the softening point of the synthetic resin is low, it is not always necessary to use a pressurizing means. However, when the softening point is 100 ° C. or higher, it is necessary to pressurize so that the aqueous medium does not boil.
[0024]
Next, the second step of the present invention will be described.
In the second step, the mixture of the resin melt obtained in the first resin step and the high-temperature aqueous medium is mechanically converted into the aqueous medium while maintaining the temperature around the softening point of the synthetic resin. Emulsified and dispersed.
[0025]
An apparatus for mechanically emulsifying and dispersing the resin melt in an aqueous medium while maintaining the temperature around the softening point of the synthetic resin is not particularly limited, but a ring-shaped stator having a slit and a ring-shaped having a slit. It is preferable to use a high-speed rotation type continuous emulsification disperser having a structure in which a rotor is provided on the same axis so that the stator and the rotor are engaged with each other while maintaining a slight gap.
[0026]
The high-speed rotation type continuous emulsification disperser of the present invention continuously injects a resin melt and a high-temperature and high-pressure aqueous medium of 100 ° C. or higher, and decomposes the synthetic resin at a temperature around the softening point of the synthetic resin. It is a device with a structure that can be rapidly and uniformly mixed, emulsified and dispersed under a high temperature and high pressure below the temperature, and continuously discharged.
[0027]
The high-speed rotation type continuous emulsification disperser can emulsify and disperse the synthetic resin melt in the aqueous medium by rotating the rotor at a high speed. The temperature of this emulsifier is required to maintain the temperature of the mixture at a temperature around the softening point of the synthetic resin in order to keep the synthetic resin in a constant molten state. It is preferable to install. The optimum temperature of the synthetic resin varies depending on the particle diameter of the target particles, the molecular weight of the resin, etc., but is preferably set to 80 ° C. to 220 ° C.
[0028]
The temperature in the high-speed rotation type continuous emulsification disperser is controlled at a constant temperature by the balance of the temperature of the resin melt to be supplied, the temperature of the supplied aqueous medium, the heat retention effect of the jacket and the amount of heat generated by the shearing force in the machine. .
[0029]
The pressure in the high-speed rotation type continuous emulsification disperser is determined by the vapor pressure at the in-machine temperature of the aqueous medium and the discharge pressure by the pump function of the rotor. Usually, a method of providing an automatic pressure control valve after cooling the aqueous dispersion of resin fine particles, keeping the internal pressure constant, and continuously taking out the aqueous dispersion under atmospheric pressure is preferable.
[0030]
In the high-speed rotation type continuous emulsification disperser, a mixture of the resin melt and the high-temperature aqueous medium is supplied to a high-speed rotation type continuous emulsification disperser, and the mixture is fed into the slit and the above-mentioned by high-speed rotation of the rotor. Flowing through the gap from the inner center of the rotor in a centrifugal direction, applying shearing force while passing through the stator slit and the rotor slit, and the mixture is a gap between the stator and the rotor. Fine dispersion is achieved by applying shear stress while passing through. Since the stator and the slit of the rotor can achieve the same effect with a nozzle, both the stator and / or the rotor can be changed to a nozzle.
[0031]
The high-speed rotation type continuous emulsification disperser preferably used for mechanical fine dispersion of the present invention will be described below with reference to the drawings.
The stator 1 of the high-speed rotating type emulsifying disperser is fixed at the same center, and the center is opened as a liquid inlet 2 communicating with the raw material inlet. On the circular surface of the stator 1, ring-shaped projections 3 that are concentric with the stator and project in a multistage shape with one or more stages. A circumferential groove 4 is formed in the gap between the protrusions, and a plurality of slits 5 are formed in each protrusion. The widths of these slits are 0.6 mm to 3.0 mm, and 12 to 72 slits are attached to each ring-shaped protrusion to form a comb tooth shape. The width of the slit is preferably smaller as the protrusions on the outer periphery decrease the particle diameter of the supplied liquid.
[0032]
A drive shaft 6 is attached to the center of the other inner wall of the high-speed rotation type continuous emulsification disperser, and is connected to the drive unit to rotate at high speed.
The rotor 7 of the high-speed rotation type continuous emulsification disperser is fixed to the tip of the drive unit in parallel with the stator and on the same central axis. On the facing surface of the rotor that faces the stator, a multi-stage projection 8 having one or two or more annular steps that are concentric with the rotor is provided. Similar to the stator, each rotating protrusion has a circumferential groove 9 formed in the gap between the protrusions, and a plurality of slits 10 are formed in each protrusion.
[0033]
The stator 1 and the rotor 7 are used in a state in which the protrusion 3 and the circumferential groove 4 of the stator and the protrusion 8 and the circumferential groove 10 of the rotor are engaged with each other while maintaining a slight gap. Provided.
[0034]
In the high-speed rotation type continuous emulsification disperser used in the present invention, a mixture of the resin melt and the high-temperature high-pressure aqueous medium is supplied to the gap formed by the biting, and the mixture flows in the centrifugal direction from the inner core of the rotor. The resin melt is emulsified and dispersed in an aqueous medium by receiving shearing force due to high-speed rotation of the rotor and receiving shear stress while the mixture passes through the gap between the stator and the rotor. To do.
[0035]
When the rotor 7 rotates at a high speed, the resin melt and the high-temperature high-pressure aqueous medium supplied to the main liquid inlet 2 of the high-speed rotation type continuous emulsification disperser enter the slits of the protrusions of the innermost rotor, and the centrifugal force Is discharged from the outer periphery of the protrusion of the rotor, pressed against the protrusion of the innermost stator, and enters the slit of the protrusion of the stator. The mixed liquid that has entered the slit is pushed by the mixture that has entered the slit of the innermost rotor by centrifugal force and is pushed out into the circumferential groove of the second rotor. At this time, the mixture is subjected to shearing force by the innermost stator protrusion and the second rotor protrusion, and is also subjected to shear stress as it passes through the interval between the stator and rotor. When the mixed solution joins, further shearing force is applied, and it is pushed by the subsequent mixed solution and enters the slit of the protrusion of the second stator, and the mixture is sequentially moved in the centrifugal direction while receiving the same thing as above. , Fine dispersion is completed.
[0036]
The relationship between the flow of this mixture and the shearing force and shear stress is as shown in FIG.
The rotation speed of the rotor of the high-speed rotation type continuous emulsification disperser is controlled by a drive motor connected to the drive shaft. The larger the rotation speed and the higher the peripheral speed, the larger the shearing force, and the smaller the particle diameter of the synthetic resin. When a powder coating material having an average particle diameter of 10 microns or less is produced using a rotor having a diameter of 10 cm, the preferred number of rotations is 3,000 to 10,000 rpm.
[0037]
Cavitron (Eurotech Co., Ltd.) can be cited as an example of an apparatus commercially available as the high-speed rotation type continuous emulsification disperser of the present invention.
Next, the third step of the present invention will be described.
[0038]
The glass transition temperature of the synthetic resin as quickly as possible while the generated resin particles collide with each other in the aqueous dispersion of resin fine particles obtained from the outlet of the high-speed rotating continuous emulsion disperser. Cool rapidly to the following temperature.
[0039]
As a device for rapidly cooling, a commercially available heat exchanger can be used, and cooling is performed while exchanging heat with cooling water. The cooling rate is not particularly limited, but is preferably 10 ° C./second or more so as not to generate aggregates.
[0040]
After being rapidly cooled to near the glass transition temperature of the synthetic resin, the pressure is returned to atmospheric pressure by a pressure control valve to obtain a slurry of resin fine particles.
Although it is possible to directly use this slurry as a powder slurry paint, a viscosity modifier can be added as necessary. By adding a viscosity modifier, it is possible to obtain the effect of maintaining the suspended resin fine particles and giving a rheology suitable for spray coating. As a viscosity modifier, an acrylic resin etc. are mentioned, for example, Primal ASE-60 (made by Nippon Acrylic Chemical) is mentioned as a specific product.
[0041]
One example of the flow from the first step to the third step will be described with reference to FIG.
That is, the resin melt is supplied from the tank 12 containing the resin melt produced by the above method to the high-speed rotation type continuous emulsification disperser 11 through the resin pump 13 and at the same time, the aqueous medium tank 14 containing the aqueous medium. From this, a high-temperature aqueous medium is obtained through the heat exchanger 15 for heating, and this high-temperature aqueous medium is supplied to the high-speed rotation type continuous emulsification disperser 11 via the pump 16. The resin melt and the high-temperature aqueous medium are emulsified and dispersed in the emulsification disperser 11 to obtain a resin melt aqueous dispersion. The aqueous dispersion is immediately passed through the cooling heat exchanger 17 and cooled to obtain a resin aqueous dispersion. The pressure in the entire flow process is adjusted by the pressure adjusting valve 18.
[0042]
The method for producing a powder slurry paint of the present invention can continuously perform a series of steps from a resin melt and a high-temperature aqueous medium to cooling through a high-speed rotation type continuous emulsification disperser.
[0043]
In the present invention, as described above, a mixture of a resin melt and a high-temperature high-pressure aqueous medium is used to generate high shearing force, shear stress, and high-frequency pressure fluctuations with a high-speed rotary type emulsifying disperser, and use a powerful stirring and crushing action Thus, solventless emulsification dispersion is performed.
[0044]
Further, although elution of water-soluble components is not zero at all, washing of the synthetic resin particles is almost unnecessary, and it may be simply filtered off. Also in this respect, the present invention is advantageous in that the process is simple and the entire process is continuous.
[0045]
The governing factors of the average particle size of the resin fine particles to be produced are (1) the rotational speed of the rotor of the emulsifying disperser, and (2) the temperature of the synthetic resin and the aqueous medium. If these numerical values are all increased, the water dispersibility of the synthetic resin increases, and the particle diameter of the synthetic resin fine particles decreases.
[0046]
This slurry of resin fine particles can be dehydrated, dried, and then classified so as to have a desired particle size distribution in the same manner as in the dry method to obtain a powder coating material composed of resin fine particles having a specific particle size. . In this case, by connecting a washing device, a dehydrating device, a drying device, and a classification device to the cooling heat exchanger, from a resin melt and a high-temperature aqueous medium to drying and classification through a high-speed rotation type continuous emulsification disperser. The series of steps can be performed continuously. Of course, after the rapid cooling is made into a continuous process and the powder slurry is obtained, the resin may be washed in a tank and dehydrated and dried. In the classification step, wet classification using a wet cyclone may be used in combination.
[0047]
【Example】
Examples of the present invention are shown below, but the present invention is not limited by these Examples. All parts and% in the examples are based on weight.
[0048]
Example 1 <Production of UV-curable powder slurry coating>
(1) Manufacture of urethane acrylate used for UV curable powder slurry paint The following composition was used.
[0049]
Isophorone diisocyanate 58.2 parts Dibutyltin dilaurate 0.1 part 3,5-di-tert-butyl-4-hydroxytoluene 0.3 part These mixtures are heated to 65 ° C., whereupon 32.4 parts hydroxypropyl acrylate Was then added dropwise and the mixture was then stirred until the NCO content was 13% or less. Next, the number of stirring revolutions was increased and the temperature was slowly raised to 120 ° C. Meanwhile, 9 parts of glycerol are added dropwise over 1 hour. Next, the resin melt was taken out, cooled, and pulverized to obtain a white powder having a softening point (ring ball method) of 75 ° C. and a melt viscosity (ICI cone plate viscometer) of 76 dPas at 150 ° C.
[0050]
(2) Production of UV curable powder slurry paint 100 parts of this urethane acrylate, 233 parts of polylite PB958 (unsaturated polyester resin: manufactured by Dainippon Ink and Chemicals), 11 parts of diacetone acrylamide, Irgacure 651 (benzyldimethyl ketal Ciba Geigy) 15 parts and 11 parts of BYK361 (acrylic resin BYK Chemie) were charged in the kneaded material melt tank shown in FIG. 5, heated to 110 ° C., and fed into the Cavitron CD1010 at a rate of 100 g / min.
[0051]
Ion exchange water containing 0.1% of polyvinyl alcohol (hereinafter referred to as PVA) in the aqueous medium tank of FIG. The rotor was operated at a rotational speed of 8000 rpm and a pressure of 2 kg / cm ² , and the produced slurry was cooled from 110 ° C. to 65 ° C. within 10 seconds and taken out.
[0052]
In order to facilitate spray coating on this slurry, 1% by weight of Primal ASE-60 (acid-containing crosslinked acrylic emulsion, viscosity modifier: manufactured by Nippon Acrylic Co., Ltd.) was added. The obtained slurry is homogenized by pulverizing the agglomerate and then filtered through a 400 mesh screen (37 microns), and is substantially spherical UV curable powder having an average particle size of 2 microns and a maximum particle size of 10 microns or less. A slurry paint was obtained.
[0053]
(3) UV-curable powder coating film This slurry coating was spray-coated on a cold-rolled steel panel to a thickness of about 1 mil. This coating was heated to 100 ° C. for 15 minutes to evaporate water, melt the resin, and then irradiated with an ultraviolet lamp (120 w / cm, 10 m / min, 7 Pass, 840 mj / cm ² ). A scratch-resistant coating film was obtained.
[0054]
Example 2 <Production of powder slurry paint>
Fined A-207S (acrylic resin: manufactured by Dainippon Ink & Chemicals) 84%, dodecanedioic acid (curing agent) 16%, acronal 4F (flow control agent: manufactured by BASF) 0.5% premixed with a mixer Then, it is fed into the screw mixer 12 in FIG. The screw mixer was sent to the extruder 13 shown in FIG. 5. The extruder was heated to 100 ° C. and kneaded, and fed into the Cavitron CD1010 at a rate of 100 g / min. Ion exchange water containing 0.1% of PVA in the aqueous medium tank of FIG. 5 was fed into the Cavitron at a rate of 1 liter per minute while being heated to 100 ° C. with a heat exchanger. The rotor was operated at a rotational speed of 8000 rpm and a pressure of 2 kg / cm ² , and the produced slurry was cooled from 100 ° C. to 65 ° C. within 10 seconds and taken out.
[0055]
In order to facilitate spray coating on this slurry, 1% by weight of Primal ASE-60 was added, and the agglomerates were pulverized and homogenized with a homogenizer and then filtered through a 400 mesh screen (37 microns). A nearly spherical powder slurry paint of 10 microns or less was obtained.
[0056]
The slurry paint was spray coated to a cold rolled steel panel with a thickness of about 1 mil. This panel was pre-baked at 100 ° C. for 15 minutes and then baked at 150 ° C. for 20 minutes to obtain a transparent, hard and smooth coating film.
[0057]
【The invention's effect】
According to the present invention, a powder slurry paint having a small particle diameter can be produced by a continuous production method that is extremely easy and highly productive without using an organic solvent.
[0058]
Further, according to the method for producing synthetic resin particles of the present invention, even a resin that could not be pulverized by conventional pulverization means can be pulverized economically.
[Brief description of the drawings]
FIG. 1 is a perspective view of a stator and a rotor of a rotary continuous emulsification disperser used in the present invention.
FIG. 2 is a view showing a cross section of a main part of a rotary continuous emulsification disperser used in the present invention.
FIG. 3 is a diagram illustrating a combination state of a stator protrusion and a rotor protrusion when the AA ′ portion of FIG. 2 is viewed from the side surface.
FIG. 4 is a diagram showing the force applied to the fluid flowing between the stator and the rotor due to the rotation of the rotor of the rotary continuous emulsification disperser used in the present invention.
FIG. 5 is an explanatory diagram of a method for producing a powder slurry paint according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Stator 2 Liquid inlet 3 Stator protrusion 4 Stator circumferential groove 5 Protrusion slit 6 Drive shaft 7 Rotor 8 Rotor protrusion 9 Rotor circumferential groove 10 Protrusion slit 11 Rotary continuous emulsification Disperser 12 Resin melt tank or screw mixer 13 Resin pump or extruder 14 Aqueous medium tank 15 Heating heat exchanger 16 Aqueous medium pump 17 Cooling heat exchanger 18 Pressure control valve

Claims (8)

(1) Resin melt (a) obtained by heating and melting a kneaded product of a synthetic resin for powder coating, a curing agent and / or a photoinitiator, and an aqueous solution heated to a softening point of the synthetic resin ± 30 ° C. (2) Mixing the resin melt (a) in the aqueous medium (b) by mechanical means while maintaining the temperature of the mixture at the softening point of the synthetic resin ± 30 ° C. (3) A method for producing a powder slurry paint, characterized in that it is rapidly cooled immediately after being emulsified and dispersed.   The manufacturing method of Claim 1 which adds a viscosity modifier to the obtained powder slurry coating material after rapid cooling.   The manufacturing method of Claim 1 or 2 with which the said synthetic resin for powder coatings contains 1 or more types of resin selected from the group which consists of an acrylic resin, an epoxy resin, and a polyester resin.   The method according to claim 1 or 2, wherein the synthetic resin for powder coating comprises an unsaturated polyester resin and urethane acrylate and / or urethanized vinyl ether.   As a mechanical means for emulsification and dispersion, a ring-shaped stator having slits and a ring-shaped rotor having slits are coaxially arranged so that the stator and the rotor are engaged with each other while maintaining a slight gap. The manufacturing method of any one of Claims 1-4 which uses the provided high-speed rotation type continuous emulsion disperser.   A mixture of a resin melt obtained by heating and melting a kneaded product of a synthetic resin for powder coating, a curing agent and / or a photoinitiator, and, if necessary, a color pigment, and an aqueous medium, the high-speed rotation type The mixture is supplied to a continuous emulsifying disperser, and the mixture is caused to flow from the inner center of the rotor to the centrifugal direction through the slit and the gap by high-speed rotation of the rotor, and passes through the stator slit and the rotor slit. The resin melt is emulsified and dispersed in an aqueous medium by applying a shearing force while applying a shear stress while the mixture passes through a gap between the stator and the rotor. 5. The production method according to 5.   The manufacturing method according to claim 1, wherein the resin melt (a) is a resin melt containing a color pigment.   The production method according to claim 1, wherein the aqueous medium (b) is an aqueous medium heated to a softening point of ± 30 ° C. of the synthetic resin by heating and further pressurization.

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