JPH0260508B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a resin extrusion device having a rotating disk.

[Prior art] Molten resin is placed between a rotating disk and a stationary plate facing it, and the resin is pushed through a nozzle hole provided at the center of the stationary plate using stress generated toward the center of the disk. The device used to pump out the pump is known as a Weisenberg pump, but as a result of making an experimental model, it was found that there were various problems that needed to be solved before it could be used as a practical device. One of these is the backflow phenomenon of molten resin. These phenomena will be explained using the side sectional view of a typical Weisenberg pump shown in FIG.

In Fig. 3, 1 is a fixed plate, 2 is a nozzle hole,
3 is a rotating disk, 4 is its outer peripheral side surface, 5 is a fixed outer cylinder, and 6 is its inner surface. 7 is a hopper, 8 is a heater necessary for initial heating, etc. 9 is a rotating shaft that drives the disk, 10 is a gap between the outer peripheral side of the rotating disk and the inner surface of the fixed outer cylinder, which is the minimum required for accuracy in machining etc. 0.2
A spacing of about mm is required. Reference numeral 11 indicates a gap between the rotating disk and the stationary plate, and it is said that a gap of about 3 to 10 mm is preferable for generating the Weisenberg phenomenon.

If you continue to operate such a device for more than a few tens of minutes,
The molten resin oozes out to the back surface 12 of the rotating disk 3 through the gap 10 between the outer circumferential side surface 4 of the rotating disk and the inner surface 6 of the fixed outer cylinder, and the resin is thermally decomposed in this area, emitting smoke, and the heater 8 This is accompanied by undesirable phenomena such as accumulation on surfaces such as the like and the formation of carbides. This will be referred to as a resin backflow phenomenon.

Narrowing the interval 10 to prevent this backflow phenomenon means that the device is heated to a high temperature and undergoes thermal expansion;
There is a limit due to the large radius of rotation of the disc and the fluctuation of the gap caused by the slight deviation between the center of rotation and the center of the disc. More fundamentally, the occurrence of the backflow phenomenon is caused by the pressure acting on the inner surface of the fixed outer cylinder caused by the centrifugal force acting on the molten resin attached around the rotating disk, and a force that constantly causes backflow is generated in the gap 10. Therefore, it cannot be easily prevented by narrowing the gap.

Furthermore, in actual use of the extrusion device, it is necessary to stop the rotating disk after supplying the resin. During this stop, the molten resin moves downward within the device and further flows into the gap 10. The resin that has flowed into the gap 10 will continue to flow even if the rotation of the rotating disk is restarted.
It is not possible to return to gap 11. If there is resin in the gap 10, it will cause an increase in rotational torque, and if even a small amount remains, it will oxidize due to long-term heating.
It's going to be colored. When this gets mixed into the resin in the gap 11, it causes discoloration of the molded product.

[Problems to be Solved by the Invention] An object of the present invention is to prevent the backflow phenomenon by a simple means without narrowing the gap around the rotating disk 3, and at the same time stop the rotation of the rotating disk 3. It is an object of the present invention to provide a resin extrusion device that can prevent problems caused by resin flowing into the gap when the resin is extruded.

[Means for Solving the Problems] In order to achieve the above object, the resin extrusion device of the present invention puts molten resin between a rotating disk and a fixed plate facing it, and suppresses the stress generated in the direction of the center of the disk. It is possible to extrude resin from a nozzle hole provided in the center of the fixed plate by using the rotating disk, and the device has a structure in which a hopper is opened to supply molten resin between the rotating disk and the fixed plate facing it. In this method, screw-shaped ridges and grooves that are inclined with respect to the axial direction are formed on the outer circumferential side of the rotating disk or the inner surface of the stationary outer cylinder, and the cross section thereof is a smooth curve and the surface is smooth. In addition, these peaks and grooves are formed in such a direction that the rotation of the rotating disk causes the resin to be extruded in the direction of the gap between the rotating disk and the fixed plate. The gap between the top of these peaks and the inner surface of the fixed outer cylinder must be at most 1 mm or less, and although it is related to the viscosity and adhesiveness of the molten resin, if it is 2 mm or more, the backflow of the molten resin must be completely suppressed. I can't. Also, the height between the top of the mountain and the bottom of the groove must be at most 2 mm or less.

Usually, the diameter of the rotating disk is several centimeters or more, and the width of the outer peripheral side surface is about 1 to 2 centimeters, so the rotating disk used in the present invention has a nearly cylindrical structure.

An attempt to prevent resin leakage by providing a screw type reverse thread is also described in the already known specification of Utility Model Publication No. 48-40700, but some of the supplied polymer It is also known that polymers attempt to leak by climbing over the screws, and Japanese Utility Model Publication No. 48-40700 is a device to further prevent this leaked polymer from flowing back.

In the present invention, a groove having an inclination with respect to the axial direction is formed in a rotating circle, with a gap between the top of the mountain and the inner surface of the fixed outer cylinder being at most 1 mm or less, and a height between the top and the bottom of the groove being at most 2 mm or less. It is provided on the outer peripheral side surface of the cylindrical body connected to the plate.

[Operations and Effects] In such a resin extrusion device, when the rotation of the rotating shaft is stopped, the resin accumulates in the lower part of the gap around the rotating disk due to gravity, and enters the gap due to fluidity. Resin that has entered the gap between the outer peripheral side surface and the inner surface of the fixed outer cylinder due to other reasons is discharged in the direction of the gap between the fixed plate and the rotating disk due to the action of the screw formed by the threads and grooves due to rotation. be done. In addition, even if resin flows into the gap around the rotating disk during rotation, it will be discharged in the same way, and as described in the examples, in the case of general-purpose resin, during extrusion, Even after approximately 11 hours of operation, no molten resin was observed to flow out onto the back surface of the rotating disk.

In addition, the area where the resin remained on the outer peripheral side is approximately
It was 10mm.

In actual equipment operation, when changing the type of raw materials, composition ratio, etc., the resin mixing part of the equipment is often disassembled, cleaned, and reassembled for reuse. At this time, if the surface of the mixing part is simple and smooth, the surfaces of the ridges and grooves will be smooth with smooth curves, and the molten resin will be removed quickly and easily.

[Example] An example of the present invention will be specifically described using FIGS. 1 and 2.

FIG. 1 is a sectional view of the extrusion mechanism of the extrusion device. FIG. 2 shows an enlarged view of a portion related to the present invention.

In the illustrated resin extrusion device, the disk surface of the rotating disk 3 facing the fixed plate 1 is entirely a single plane, and the hopper 7 that supplies resin to this extrusion device is connected to both the plates 1 and 3. The gap 11 is opened so as to be supplied from the fixed plate 1 side.

The symbols and contents added for explanation in the figure are 1 to 1.
The steps up to 12 are the same as in Figure 3. Reference numeral 13 denotes a rim-shaped member fixed to the outside of the fixed plate 1 and provided to cover the outer periphery of the rotating disk 3 with a slight gap, and the width of the cover may be 1 cm or less. Further, the outer circumferential side surface 4 of the rotating disk 3 is provided with thread-shaped ridges 14 and grooves 15.

As mentioned above, the gap 11 is 3 to 10 mm, but the gap between the edge-shaped object 13 and the rotating disk 3 is preferably about 1 mm or less, and in this part, the molten resin that has flowed into the gap 11 easily due to the Weisenberg effect. Therefore, the resin can be prevented from entering the gap 10 during rotation.

The main structure for preventing backflow in this extrusion device is to prevent the resin from flowing into the gap 10 around the rotating disk 3, and at the same time to prevent problems that may occur when the rotation of the rotating disk 3 is stopped. That's the point.

That is, as shown in FIG. 2, as a structure for feeding the resin that has flowed into the gap 10 into the gap 11 as the rotating disk 3 rotates, an angle oblique to the axial direction is formed on the outer peripheral side surface 4 of the rotating disk 3. It has ridges 14 and grooves 15. These are formed so that the ridges 14 function similarly to the threads of a screw, and the resin is extruded in the direction of the gap 11 by rotation of the rotating disk 3. The depth of the groove 15 should be at most 2 mm or less, and the cross section between the groove 15 and the top of the peak 14 should be a smooth curve and the surface should be smooth. The pitch of the grooves 15 should be at most several mm or less.
If the angle of the groove 15 is shallow, the molten resin will easily flow into the gap, so it is preferable that the angle be inclined at several degrees with respect to the axis of the rotating disk.

The distance between the peak of the outer circumferential side and the inner wall surface of the fixed cylinder is 0.5 mm to 0.2 mm, and when the diameter of the disk is 100 mm, the width of the outer circumferential side is suitably 15 mm to 10 mm. The optimum conditions for these conditions differ depending on the resin used and the operability, but grooves with smooth surfaces are necessary for cleaning the equipment, etc. In addition, in Fig. 2, groove 1
The depth of 5, the width of one groove and crest, the pitch, etc. are shown more roughly than the actual dimensions for ease of understanding.

In an extrusion device having such a configuration,
When the rotation of the rotating shaft 9 is stopped, the resin accumulates in the lower part of the gap 11 due to gravity and enters the gap 10 due to its fluidity. The distance to enter is determined by the viscosity of the melted resin and the gap 1
Although it is related to the resistance of 0, in actual operation, it is not stopped for a long time in a heated state, so the entry distance is only a few centimeters at most, and with the prototype device with a disk diameter of 10 cm. , no penetration of more than 5 mm was allowed.

The resin in the gap 10, with the restart of rotation,
Due to the action of the thread formed by the threads 14 and grooves 15, it is discharged in the direction of the gap 11. Furthermore, even if resin were to flow into the gap 10 during rotation of the disc, it would be discharged in the direction of the gap 11 in the same way.

Note that substantially the same effect can be expected even if thread-shaped ridges and grooves are provided on the inner surface 6 of the fixed outer cylinder 5.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of a main part of an embodiment of a Weisenberg type extrusion apparatus according to the present invention. FIG. 2 is an enlarged sectional view of a main part of the apparatus shown in FIG. 1, showing a part related to preventing backflow of molten resin. FIG. 3 is a side sectional view of a conventionally known Weisenberg type extrusion device. 1... Fixed plate, 2... Nozzle hole, 3... Rotating disk, 4... Outer peripheral side, 5... Fixed outer cylinder, 6... Inner surface, 10, 11... Gap, 14... Mountain, 15 ……
groove.

Claims (1)

[Claims] 1 It is possible to put catalytic resin between the rotating disk and the fixed plate facing it, and use the stress generated toward the center of the disk to extrude the resin through the nozzle hole provided in the center of the fixed plate. In a device having a structure in which a hopper is opened for supplying molten resin between a rotating disk and a fixed plate facing it, there is a The thread-shaped crests and grooves are formed by a surface whose cross section is a smooth curve and the surface is smooth, and the gap between the crests of the ridges on the outer peripheral side and the inner surface of the fixed outer cylinder is 1 mm or less, The depth of the grooves is also 2 mm or less, and these peaks and grooves are formed in such a direction that the rotation of the rotating disk causes the resin to be extruded in the direction of the gap between the rotating disk and the fixed plate. A resin extrusion device with a rotating disk.