JP3695683B2 - Resin composition milling equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention provides a resin composition milling apparatus, in particular, a milling product that is extremely close to the product particle size after pulverization, so that the amount of fine powder generated during the pulverization process is small and the pulverization time can be stably obtained without causing deterioration of properties. The present invention relates to a milling apparatus for a resin composition capable of shortening the length.
[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 a pulverization process that has undergone a coarse pulverization process such as a conventional 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 fed to the rotor in the form of a thread, the resin is extended between two adjacent pins by centrifugal force and becomes a fiber, but 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, these methods are not sufficient to stably obtain a mill 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.
JP-A-10-032581, JP-A-10-035822, and JP-A-10-032583 can be cited as examples of the purpose of providing a powder coating mill. The container for collecting milling is not regulated, and the outer tank 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 adheres to the wall surface, the fusion between the milling grows using the milling as a seed, so that the milling is difficult to be cooled and promotes deterioration due to heat.
[0007]
[Problems to be solved by the invention]
Since the present invention can stably obtain milling close to the target product particle size without causing deterioration of characteristics, the pulverization time can be shortened, and the generation amount of fine powder and coarse particles is small in the pulverization process. It is an object of the present invention to provide a powder coating apparatus that can reduce the classification process and save labor.
[0008]
[Means for Solving the Problems]
The present invention can supply a resin composition melted and kneaded through a cylindrical body installed at the upper part of a rotating rotor through an opening, each of which is provided with a rotational power source, and the upper part and / or the lower part are magnetic materials on the outer periphery thereof. A plurality of rotors each having a punched wire mesh formed of a non-magnetic material having high thermal conductivity and having a small hole in contact with the heater, and heating means for heating the upper and / or lower magnetic material of the punched wire mesh A resin composition milling apparatus capable of milling a resin composition into fine particles or fibers by passing through small holes of a punched wire mesh heated uniformly by heat conduction by centrifugal force. Furthermore, the cylindrical body installed on the upper part of the rotating rotor is a double pipe type that can be cooled by passing a refrigerant between the inner wall and the outer wall, and the hole diameter of the punched wire mesh of the rotor is located inside it. The outer tank that collects the milled resin is inclined to 10 to 80 degrees in order to prevent the adhesion of the milling, and the outer circumference Is a resin composition milling apparatus provided with a cooling jacket.
[0009]
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 base 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. Mixed systems can also be used.
[0010]
According to the present invention, each of the plurality of rotors having different diameters provided with a punched wire mesh formed of a nonmagnetic material with high thermal conductivity having a small hole on the outer periphery thereof has a power source. Each rotation direction and rotation speed can be adjusted by the resin composition to be milled. However, the number of rotors is preferably two for practical use. The upper part and / or the lower part of the punched wire mesh is in contact with the magnetic material, and the magnetic material can be heated by energizing an alternating current power supply to an exciting coil installed in the vicinity. Heat is transmitted to the punched wire mesh by heating the magnetic material, and uniform heating is possible due to the high heat conduction. The melt-kneaded resin composition supplied from the opening through the double-pipe cylindrical body installed on the upper part of the rotor comes into contact with the innermost heated punched wire mesh without increasing the melt viscosity of the resin. Fine particles or fibrous materials can be easily obtained by passing through the small holes by centrifugal force. The resin composition in the form of fine particles or fibrous material is further transferred to a punched wire net located outside by centrifugal force. The hole diameter of the punched wire mesh positioned on the outer side is the same as or smaller than the hole diameter of the punched metal mesh positioned on the inner side of the punched wire mesh. By passing through the small holes of a plurality of punched wire meshes, it is possible to mill into particles closer to the product diameter. The outer tank for collecting the milled resin is preferably inclined to prevent the adhesion of the milling, and since it has a cooling jacket on its outer periphery, the grinding time can be reduced without causing deterioration of the resin characteristics due to the adhesion of the milling. Fine powder and coarse particles generated during shortening and crushing processes can be reduced.
[0011]
Next, an example of the present invention will be described with reference to the drawings. There are two rotors described here. 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 10 is supplied to the inner rotor 1 through a cylindrical body 7 cooled by passing a refrigerant between the inner wall and the outer wall. At this time, if the cylindrical body 7 is not cooled, the resin tends to adhere to the wall of the cylindrical body 7 and it becomes difficult to stably supply the resin. The inner rotor 1 is connected to a motor 11 and the outer rotor 2 is connected to a motor 12. The hole diameter of the punched wire mesh 4 formed of a nonmagnetic material with high thermal conductivity installed on the outer periphery of the outer rotor 2 is equal to or smaller than the hole diameter of the punched wire mesh 3 installed on the inner rotor 1. The magnetic material 5 in contact with the punched wire meshes 3 and 4 has an eddy current loss associated with the passage of alternating magnetic flux generated by energizing the AC coil generated by the AC power generator 8 to the exciting coil 6 provided in the vicinity thereof. And generates heat due to hysteresis loss. 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. The punched wire mesh is heated by heat conduction using the heated magnetic material as a heat source. The punched wire mesh 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 inner rotor 1 is supplied, the resin flies to the punched wire mesh 3 of the inner rotor 1 heated by centrifugal force. The resin that has contacted the punched wire mesh 3 of the heated inner rotor 1 easily passes through the holes of the punched wire mesh 3 and is discharged without increasing the melt viscosity.
[0012]
The resin that has passed through the holes of the punched wire mesh 3 of the inner rotor 1 and has been milled in the form of fine particles or fibers flies to the punched wire mesh 4 of the outer rotor 2 having the same or smaller holes as the punched wire mesh 3 of the inner rotor 1. To do. The punched wire mesh 4 of the outer rotor 2 is also heated and easily passes through the holes of the punched wire mesh 4 and is milled into smaller fine particles and fibers. Since the two rotors having different diameters have motors 11 and 12 as power sources, respectively, it is possible to separately adjust the rotation direction and the rotation speed depending on the characteristics of the resin composition to be milled, Since the punching wire mesh provided on each outer periphery is detachable, depending on the case, one of the punching wire meshes can be removed and used. Moreover, the temperature which heats a magnetic material can also be set arbitrarily by the characteristic of resin to mill. When a thermosetting resin is used, if the heating temperature is raised too much, the resin will harden and the characteristics may deteriorate and clogging may occur in the small holes of the punched wire nets 3 and 4, but in the case of appropriate temperature conditions Since the resin passes through the small holes of the punched wire nets 3 and 4 very quickly, the contact time is short and the influence on the characteristics is extremely small. Further, since the punched wire meshes 3 and 4 have extremely high thermal conductivity, they can be heated uniformly, and there is very little local change in characteristics. The discharged fine particles or fibrous composition is collected in an outer tank 9 installed around the outer rotor 2. The outer tub 9 is provided with an inclination of 10 to 80 degrees, preferably 25 to 65 degrees on the milling collision surface in order to prevent the milling from adhering to the inner wall or fusion between the milling. 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 13 is provided in the outer periphery of the collision surface, and the collision surface can be cooled. If the inner diameter of the outer tub 9 is too small, the fibrous composition is not sufficiently cooled during the flight, which may cause adhesion to the inner wall and fusion between the resins. In general, an air flow is generated by rotation of the rotor and a cooling effect is obtained, but cold air may be introduced as necessary. Although the size of the outer tub 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.
[0013]
The hole diameter of the punched wire mesh can be adjusted by the average particle diameter of the target resin composition, but the ratio of the hole diameters of the outer and inner punched wire meshes is 1 when the hole diameter of the punched wire mesh of the inner rotor is 1. The hole diameter of the punched wire mesh of the outer rotor is 1 to 0.2, preferably 0.8 to 0.4. This relationship holds for all adjacent punched wire meshes. When the hole diameter of the punched wire mesh of the outer rotor is larger than 1, the fine particle or fibrous composition that has passed through the hole of the punched wire mesh of the inner rotor does not become a smaller fine particle or fibrous composition, and the punched wire mesh of the outer rotor. Will pass through the hole. If the ratio is less than 0.2, the amount of resin passing through the punched wire mesh holes of the outer rotor is extremely small compared to the amount of resin passing through the punched wire mesh holes of the inner rotor. There is a high possibility that the resin will stay between the punched wire nets and cause characteristic deterioration.
[0014]
When the average particle diameter of the target resin composition is α, the diameter of the collected fibrous composition is adjusted to 1.0α to 15.0α and the length is adjusted to 1.0α to 30.0α. The fiber diameter and fiber length are adjusted by the supply rate of the molten powder coating resin composition, the melt viscosity, the rotational speed of the rotor, the hole diameter of the punched wire mesh, and the heating temperature. When the diameter of the fibrous composition is 15.0α or more or the fiber length is 30.0α or more, the effect of reducing fine powder and coarse particles generated in the subsequent pulverization process is small, and the pulverization efficiency cannot be sufficiently improved.
[0015]
【Example】
The present invention will be described in more detail with reference to examples.
Example 1
After blending 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 leveling agent with a Henschel mixer, the mixture is melt-kneaded with a twin screw extruder, A molten epoxy resin composition was obtained.
This has a hole diameter of 1.0 mm, a 20 cm inner rotor rotating right at 3000 rpm with a copper punched wire mesh heated to 120 ° C. with an excitation coil, and a hole diameter of 0.6 mm. Supply to an outer rotor having a diameter of 24 cm and rotating left at 3000 rpm equipped with a copper punched wire mesh heated to 120 ° C. by a coil to obtain a fibrous composition having an average fiber diameter of 200 μm and an average fiber length of 1.0 mm. It was. When this was pulverized with a pulverizer at 4000 revolutions, an epoxy resin composition having an average particle size of 68 μm and containing no fine powder of 8 μm or less and coarse particles of 200 μm or more was obtained.
[0016]
Example 2
The inner side of a diameter of 20 cm which is rotated right at 4500 rpm with a copper punched wire mesh having a hole diameter of 1.0 mm and a heated epoxy resin composition at 120 ° C., which is heated to 120 ° C. with an exciting coil. Supplied to an outer rotor with a diameter of 24 cm and rotating counterclockwise at 4500 rpm with a rotor punch and a copper punched wire mesh heated to 120 ° C. with an exciting coil and having an average fiber diameter of 1700 μm, A fibrous composition having an average fiber length of 0.8 mm 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.
[0017]
<< 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. 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.
[0018]
【The invention's effect】
In the method for producing a resin composition in the present invention, since a fiber composition having a small particle size close to the target particle size of the product and a narrow particle size distribution can be stably obtained, the pulverization time can be shortened and the pulverization step Therefore, the generation of fine powder and coarse particles can be reduced, so that 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]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 shows an example from resin kneading to fibrous product granulation for milling the resin composition of the present invention.
FIG. 2 shows an example of a cross-sectional view of a rotor and an excitation coil used in the present invention.
FIG. 3 shows an example of a cross-sectional view of a cylindrical body into which a melt-kneaded resin composition is introduced into a rotor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Inner rotor 2 Outer rotor 3 Inner rotor punching wire mesh 4 Outer rotor punching wire mesh 5 Magnetic material 6 Exciting coil 7 Cylindrical body 8 AC power generator 9 Outer tank 10 Twin screw extruder 11 Inner rotor motor 12 Motor of outer rotor 13 Cooling jacket

Claims (7)

A resin composition melt-kneaded through a cylindrical body installed on the upper part of the rotating rotor can be supplied from the opening, each of which has a rotational power source, and the upper and / or lower part is in contact with a magnetic material on the outer periphery. has a different rotor diameters with a punched wire mesh formed with a non-magnetic material having high thermal conductivity having a hole, a heating means for heating the punching wire mesh top and / or magnetic material in contact with the bottom, the A resin composition milling apparatus capable of milling a resin composition into fine particles or fibers by passing through small holes of a punched wire mesh heated uniformly by heat conduction from a magnetic material by centrifugal force.  2. The resin composition milling apparatus according to claim 1, wherein the cylindrical body installed on the upper part of the rotor is of a double tube type, and the cylindrical body can be cooled by passing a refrigerant between the inner wall and the outer wall.  3. The resin composition milling apparatus according to claim 1, wherein each of the rotors having different diameters is provided with a rotational power source, so that the rotational direction and the rotational speed can be freely changed.  The punched wire mesh formed of a nonmagnetic material with high thermal conductivity having a small hole on the outer circumference of each rotor is in contact with the magnetic material at the top and / or bottom, and the excitation provided near the magnetic material The resin composition according to any one of claims 1 to 3, wherein the magnetic material is heated by energizing the coil with an AC power supply, and the punched wire mesh formed of a nonmagnetic material having a high thermal conductivity by heat conduction can be heated uniformly. Milling equipment.  A hole diameter of a punched wire mesh formed of a nonmagnetic material having a high thermal conductivity and having a small hole on the outer periphery of the rotor is equal to or smaller than a hole diameter of a punched wire mesh of a rotor installed on the inner side thereof. 4. A milling apparatus for a resin composition according to any one of 4 above.  The outer tank for collecting the milled resin has a wall surface of the milling collision part inclined at 10 to 80 degrees, and has a cooling jacket on its outer periphery. Milling of the resin composition according to any one of claims 1 to 5 apparatus.  The number of the plurality of rotors is 2, The milling apparatus for a resin composition according to claim 1.

Images