JP3695689B2 - Resin composition milling equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a resin composition milling apparatus, and more particularly to a resin composition milling apparatus that generates a small amount of fine powder during the pulverization process and can shorten the pulverization time.
[0002]
[Prior art]
For example, in the dry method, the epoxy resin powder coating is usually produced by melting and kneading each raw material, cooling and pulverizing it. A cooling belt is mainly used for cooling. If the melt-kneaded composition is not sufficiently cooled, the pulverization efficiency decreases, and in some cases, the target particle size cannot be obtained. For the pulverization, a pulverizer, a Victory mill, a ball mill, a jet mill, or the like is used. Usually, in order to increase the pulverization efficiency, the process is divided into a coarse pulverization step for forming a mass of about 5 to 15 mm and a pulverization step for pulverization to a target particle size.
[0003]
However, when a crusher such as a hammer mill is used, the average particle size is as large as 2 to 5 mm, and the particle size distribution is widened from several μm to several tens of mm. In general, the closer the particle size of the coarsely pulverized product is to the target particle size after pulverization, the shorter the time required for pulverization, and the narrower the particle size distribution, the less fine powder can be generated by over-pulverization. When a coarsely crushed material is pulverized, the pulverization time becomes long and many fine powders and coarse particles are generated. In order to improve the yield, fine powder and coarse particles need to be pulverized again after collection and processing, which causes an increase in processing costs. That is, when the particle size before pulverization is coarse with respect to the target particle size distribution and the particle size distribution is wide, a large amount of fine powder and coarse particles are generated, so that the pulverization efficiency is lowered and the cost is increased. In particular, the generation of fine powder causes the working environment to deteriorate.
[0004]
Manufacturing methods relating to the improvement of pulverization efficiency are disclosed in JP-A-8-218643 and JP-A-8-294916. By using this method, it is possible to reduce the amount of fine powder generated as compared with the fine pulverization step through the conventional pulverization step such as a hammer mill. However, when a melt-kneaded resin is supplied to the milling mechanism without a heating means as in this method, clogging is likely to occur because the resin is cooled and becomes high viscosity during milling depending on the properties of the resin. In addition to causing deterioration of characteristics, the size of the product obtained even when milled can be non-uniform and larger than the target particle size. For example, in the case of a pin-type disk, when the melt viscosity of the resin to be supplied is low and is continuously supplied to the rotor in the form of a thread, the resin is extended by centrifugal force between two adjacent pins, and becomes a fibrous form. The length of the fiber is longer than the distance between the pins.
[0005]
If the distance between the pins is reduced to shorten the fiber length, the amount of resin between the pins is reduced, so the centrifugal force that acts is also reduced, making it difficult to separate between the pins, and the resin stays inside the rotor. . In order to increase the centrifugal force in order to prevent stagnation, it is necessary to increase the rotation speed, which requires a large amount of power and also reduces the safety of work. On the other hand, since the fiber thickness depends on the resin supply amount, it becomes thinner when the supply amount is small enough, but when the supply amount is increased to increase the production capacity, the fiber diameter becomes thicker and the milling becomes stable. I can't get it.
[0006]
Further, when the resin composition to be supplied has a high melt viscosity and cannot be continuously supplied in the form of a thread, and the resin is intermittently supplied to the rotor, the resin is supplied locally to the pins. Accordingly, the resin is locally excessively supplied, and the resin is pushed out from the entire gap portion of the pin, so that it becomes a non-uniform plate shape and a very large shape. The same can be said for the vane disk. That is, this method is not sufficient for stably obtaining a milling product capable of shortening the grinding time.
Conventional production methods using a rotor include JP-A-50-121529, JP-A-50-121530, JP-A-59-203448, and the like. It is intended to be manufactured and is different from the present invention.
[0007]
Further, as an object of providing a powder coating device milling apparatus, there are JP-A-10-032581, JP-A-10-032582, JP-A-10-032583, and in these production methods, In the container for collecting milling, the outer tub is perpendicular to the flight direction of the milled fine particles or fibrous resin composition. In this case, the wall surface receives the collision energy corresponding to the speed energy of milling without relaxation, so that the milling is likely to adhere to the wall surface, and the wind flow generated by the rotation of the rotor is in the direction of pressing the milling against the wall surface. Because it works easily, it stays near the wall surface, and the flying speed of the milling is sufficiently high so that the direction of reflection after the wall collision is almost the same as the incident direction, which increases the probability of collision with milling flying later. When the milling is fused, the heat capacity is increased and it is easy to adhere to the wall surface. Once the milling has adhered to the wall surface, the milling is further fused with the milling as a seed, so that the milling is less likely to be cooled and promotes deterioration due to heat.
[0008]
JP-A-11-309713 can be cited as an object of providing a resin composition milling apparatus that solves these problems, but the milling immediately collected in a container from the outer tank or from the outer tank is Depending on the melt-kneading and the operating conditions of the rotor, the outer periphery may be cooled during flight, but the inside may store heat, and when such milling is deposited, the milling may cause fusion. In some cases, deterioration of characteristics may occur due to thermal history.
[0009]
[Problems to be solved by the invention]
In the present invention, milling time closer to the target product particle size can be stably obtained without causing deterioration of characteristics, so that the grinding time can be shortened, and the generation amount of fine powder and coarse particles is small in the grinding process. Thus, an object of the present invention is to provide a powder coating apparatus that can reduce the classification process or save labor.
[0010]
[Means for Solving the Problems]
That is, according to the present invention, a resin composition melt-kneaded through a cylindrical body installed on the upper part of a rotating rotor can be supplied from the opening, and the upper and / or lower part has small holes in contact with the magnetic material on the outer periphery thereof. A rotor having a punched wire mesh formed of a non-magnetic material with high thermal conductivity and a means for heating the upper and / or lower magnetic material of the punched wire mesh, and a small size of the punched wire mesh uniformly heated by heat conduction. The outer tank for milling the resin composition into fine particles or fibers by passing through the holes with centrifugal force and collecting the milled resin has a wall surface of the milling collision part inclined at 10 to 80 degrees, and its outer periphery In the resin composition mill equipped with a cooling jacket, the outer tank has a discharge port for taking out the milled powder, and the air is cooled by the air transportation equipment provided at the end, A milling device which can be further transported.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The melt-kneaded resin composition in the present invention is an epoxy resin, epoxy-polyester resin, polyester resin, acrylic-polyester resin, thermosetting resin such as polyimide resin, or polyvinyl chloride resin, polyethylene resin, polyamide resin, The main resin is a thermoplastic resin such as ABS resin or fluorine resin, and various raw materials such as curing agents, fillers, pigments, and other additives are blended depending on the application. The base resin is modified depending on the application. It may be a resin or a mixture.
[0012]
The apparatus of the present invention has a rotor with a punched wire mesh formed of a non-magnetic material with high thermal conductivity having a small hole whose upper and / or lower part is in contact with the magnetic material on the outer periphery thereof, and in the vicinity of the magnetic material. In the milling apparatus of the resin composition capable of heating the magnetic material of the upper part and / or the lower part of the punched wire mesh by energizing the exciting coil installed in The melted and kneaded resin composition is supplied from the opening through a double-pipe cylinder installed at the top of the rotating rotor, and comes into contact with a punched wire mesh heated by heat conduction, increasing the melt viscosity of the resin. Without passing through the small holes by centrifugal force, it can be easily made into fine particles or fibrous materials.
[0013]
The outer tank that collects the milled resin has a double cone shape with a cooling jacket, and the slope of the upper cone prevents the milling from adhering and follows the airflow generated by the rotation of the rotor on the lower cone. Since milling falls, milling can be cooled efficiently. In addition, the double cone-shaped outer tank lower cone part has a discharge port for taking out the flour, and is connected to the pneumatic transportation equipment with rotating blades installed in the pipe path provided at the tip, and the flour to be transported is By colliding with rotating blades that are rotating while being cooled by air, when collected in the product collection container, it is crushed to a particle size closer to the final product diameter than immediately after milling that has jumped out of the rotor mesh, and the specific surface area Since the cooling of the milling is promoted by the increase, the grinding time can be shortened and the fine powder and coarse particles generated during the grinding process can be reduced without causing deterioration of the resin characteristics due to the adhesion of the milling.
[0014]
Next, an example of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view for carrying out the method for milling a resin composition of the present invention, FIG. 2 shows a rotor and an exciting coil, and FIG. 3 shows a cylindrical body installed on the top of the rotor. The resin melt-kneaded by the twin-screw extruder 9 is supplied to the rotor 1 through a cylindrical body 5 cooled by passing a refrigerant between the inner wall and the outer wall. At this time, when the cylindrical body 5 is not cooled, the resin tends to adhere to the wall of the cylindrical body, and it becomes difficult to stably supply the resin.
[0015]
The rotor 1 is connected to a motor 10 and can be rotated at an arbitrary number of rotations. A magnetic material 3 in contact with a punched wire mesh 2 formed of a non-magnetic material having a uniform hole diameter and having a uniform hole diameter provided on the outer periphery of the rotor 1 is connected to an excitation coil 4 provided in the vicinity thereof, and an AC power generator 6 is heated by the eddy current loss and hysteresis loss accompanying the passage of the alternating magnetic flux generated by energizing the AC power source generated by 6. Examples of the magnetic material include iron material and silicon steel, and one type or two or more types of magnetic materials can be used in combination.
[0016]
The punched wire mesh is heated by heat conduction using the heated magnetic material 3 as a heat source. The punched wire mesh 2 is formed of a nonmagnetic material having a high thermal conductivity and can be heated extremely uniformly. Examples of this nonmagnetic material include copper and aluminum, and one or two or more kinds of magnetic materials can be used in combination. After the resin is supplied to the rotor 1, the resin flies to the punched wire mesh 2 heated by centrifugal force.
[0017]
The resin that has contacted the heated punched metal mesh 2 is easily discharged through the holes of the punched metal mesh 2 without increasing the melt viscosity. The heating temperature can be arbitrarily set depending on the characteristics of the applied resin. When using a thermosetting resin, if the heating temperature is raised too much, the resin will harden and the characteristics may deteriorate and clogging may occur in the holes of the punched wire mesh 2. However, under appropriate temperature conditions, the resin Since it passes through the small hole of the punched wire mesh 2 very quickly, the contact time is short and the influence on the characteristics is very small. Further, since the punched wire mesh 2 is heated uniformly, there is very little local change in characteristics.
[0018]
The resin composition milled in the form of fine particles or fibers by passing through the holes of the punched wire mesh 2 is collected in an outer tank 8 installed around the rotor 1. The outer tub 8 has a double cone shape, and the upper cone portion is provided with an inclination of 10 to 80 degrees, preferably 25 to 65 degrees on the collision surface in order to prevent the milling from adhering to the inner wall and the fusion of the milled powder. It is. When the inclination is too small, the collision energy of milling cannot be sufficiently dispersed, and adhesion to the wall surface occurs. If the inclination is too large, the rate of decrease in the flying speed of the milling is small and the flight direction is toward the outer tank wall surface, which may cause adhesion during the next wall surface collision. Moreover, since it becomes easy to adhere when the temperature of the collision surface with milling becomes high, the cooling jacket 7 is provided in the outer periphery, and the whole outer tank can be cooled.
[0019]
Milling that collides with the upper cone falls along the air flow generated by the rotation of the rotor 1 while being cooled on the lower cone. An air flow is generated in the outer tub 8 by the rotation of the rotor 1, and one or more air flow generators 14 can be attached and used together to further strengthen the air flow. The airflow generation device 14 is not limited as long as it is a device that can forcibly generate an airflow such as a blower or compressed air. If the inner diameter of the outer tub 8 is too small, the milling is not sufficiently cooled during the flight, which may cause adhesion to the inner wall and fusion between the mills. Although the size of the outer tub 8 depends on the amount of resin to be processed, for example, when the diameter of the rotor is 20 cm, adhesion and fusion can be prevented if the inner diameter is 100 cm.
[0020]
The double cone-shaped outer tub 8 has a discharge port for taking out the flour in the lower cone part, and is connected to the air transportation facility 12 in which the rotary blades 11 are installed in the piping path provided at the tip, and the flour to be transported Is collided with the rotating blades 11 that are rotating while being cooled with air, so that it is crushed to a particle diameter closer to the final product diameter than that immediately after milling that has jumped out of the rotor mesh, and the specific surface area is increased, thereby cooling. Is promoted, and after being sufficiently cooled, is carried to the milling collection container 13. Therefore, although the surface is cooled during the flight immediately after milling, even if the milled powder is still stored inside when it is collected in the outer tank 8, it is sufficiently cooled and then transported to the milling recovery container 13 for milling. It is possible to prevent deterioration of characteristics due to adhesion between each other and heat history.
[0021]
Since the collision energy between the milling and the rotary blade 11 is sufficiently smaller than the pulverization energy of a normal pulverizer, no fine powder is generated by the collision with the rotary blade 11. The material, the number of blades, and the number of attachments are not limited as long as the rotating blades 11 pulverize when colliding with milling. In addition, a fan or blower of an air transportation device can be attached in front of the milling recovery container 13 to replace the rotating blades.
[0022]
When the average particle diameter of the resin composition obtained after pulverization is α, the average minor axis diameter of the collected fine particles or fibrous milling is 0.5α to 12.0α, and the average major axis diameter is 1.0α to 20 .0α is adjusted. The average minor axis diameter and the average major axis diameter are adjusted by the supply rate of the molten resin composition, the melt viscosity, the rotation speed of the rotor, the hole diameter of the punched wire mesh, and the heating temperature. Milling that is closer to the product particle diameter than the average minor axis diameter of 1.0α to 20.0α and the average major axis diameter of 1.0α to 40.0α obtained by the conventional Japanese Patent Laid-Open No. 11-309713. Therefore, the effect of reducing fine powder and coarse particles generated in the pulverization step is great.
[0023]
【Example】
The present invention will be described in more detail with reference to examples.
Example 1 5 kg of bisphenol A type epoxy resin (epoxy equivalent 850), 5 kg of crystalline silica powder, 0.06 kg of 2-methylimidazole, and 0.02 kg of a leveling agent were blended with a Henschel mixer and then melt-kneaded with a twin screw extruder. And it was set as the 120 degreeC molten epoxy resin composition.
This has a hole diameter of 1.0 mm, and is provided with a copper punched wire mesh heated to 120 ° C. by an exciting coil and having a diameter of 24 cm and 3000 rpm. p. The fibrous composition having an average minor axis diameter of 90 μm and an average major axis diameter of 134 μm was obtained. When this was pulverized with a pulverizer at 4000 rpm, an epoxy resin composition having an average particle size of 50 μm and containing no fine powder of 7 μm or less and coarse particles of 170 μm or more was obtained.
[0024]
Example 2 The same melt epoxy resin composition at 120 ° C. as in Example 1 having a hole diameter of 3.0 mm and having a copper punched wire net heated to 120 ° C. with an exciting coil and having a diameter of 3000 r. p. The fibrous composition having an average minor axis diameter of 100 μm and an average major axis diameter of 150 μm was obtained. When this was pulverized with a pulverizer at 4000 revolutions, an epoxy resin composition having an average particle size of 60 μm containing no fine powder of 10 μm or less and coarse particles of 180 μm or more was obtained.
[0025]
Comparative Example 1 5 kg of bisphenol A type epoxy resin (epoxy equivalent 850), 5 kg of crystalline silica powder, 0.06 kg of 2-methylimidazole, and 0.02 kg of a leveling agent were blended with a Henschel mixer and then melt-kneaded with a twin screw extruder. did. After cooling with a cooling belt, coarse pulverization was performed with a hammer mill to obtain a coarsely pulverized product having an average particle size of 800 μm and a particle size distribution of 40 μm to 10 mm. When this was pulverized with a pulverizer at 4000 rpm, an epoxy resin composition having an average particle size of 70 μm containing 11 wt% of fine powder of 10 μm or less and 8% of coarse particles of 180 μm or more was obtained.
[0026]
【The invention's effect】
In the method for producing a resin composition in the present invention, it is possible to stably obtain fine particles having a small particle size close to the target particle size of the product and a narrow particle size distribution, so that the pulverization time can be shortened and the pulverization step. Thus, the generation of fine powder and coarse particles can be reduced, and the productivity can be improved and the working environment can be improved along with the reduction of the classification process or labor saving.
[Brief description of the drawings]
FIG. 1 shows one example from resin kneading to milling collection for milling the resin composition of the present invention.
FIG. 2 shows an example of a cross-sectional view of a rotor and excitation coil 4 used in the present invention.
FIG. 3 shows an example of a cross-sectional view of a cylindrical body 5 for introducing a melt-kneaded resin composition into a rotor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Rotor 2 Punching wire net 3 Magnetic material 4 Excitation coil 5 Cylindrical body 6 AC power generator 7 Cooling jacket 8 Outer tank 9 Twin screw extruder 10 Motor 11 Rotor blade 12 Air transport equipment 13 Flour collection container 14 Airflow generator

Claims (2)

The resin composition melt-kneaded through the cylindrical body installed on the upper part of the rotating rotor can be supplied from the opening, and the upper and / or the lower part has small holes in contact with the magnetic material on the outer periphery, and has high thermal conductivity. A rotor having a punched wire mesh formed of a non-magnetic material, and a means for heating the magnetic material in contact with the upper and / or lower portions of the punched wire mesh, and the punched wire mesh heated uniformly by heat conduction from the magnetic material The outer tank for milling the resin composition into fine particles or fibers by passing through the small holes of the tube and collecting the milled resin, the wall surface of the milling collision part is inclined at 10 to 80 degrees, In the resin composition milling apparatus provided with a cooling jacket on its outer periphery, the lower part of the outer tub has a discharge port for taking out the milling, and the milling is air-cooled by an air transportation facility provided at the end. While, a milling equipment that can be transported from the outer tank, the outer tank for collecting the milled resin, a double cone type, after the milling has collided with the upper cone portion having a cooling jacket on the outer periphery, on the outer periphery thereof A resin composition milling apparatus capable of cooling a milling powder by dropping the milling along an air flow generated by the rotation of a rotor through a lower cone portion provided with a cooling jacket .  The apparatus for milling a resin composition according to claim 1, wherein the discharge port provided in the lower part of the outer tub is connected to an air transport facility in which a rotary blade is attached in the piping path.

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