JPH0534136B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is applicable to plastic extruders, rubber extruders,
This invention relates to a plasticizing device such as the above, and particularly to a plasticizing device whose raw material supply capacity can be easily adjusted depending on the type and form of the raw material.

(Prior Art) FIG. 5 shows a raw material supply section with a conventional structure. The illustrated one has grooves 4 on the inner surface of the raw material supply cylinder 2 whose depth gradually decreases along the longitudinal direction of the screw 1. It is a sectional view, and 3 is a raw material supply port. In addition to this example, although not shown in the drawings, it is already known that a cylinder is employed in which the inner surface is simply formed in a circular cross section without having a groove on the inner surface of the cylinder. The role of the supply section in these plasticizing devices is to prevent the feeding of more resin than necessary and to ensure that the resin feeding capacity is not insufficient. This feeds an appropriate amount of resin into the plasticized area.

However, in the conventional equipment described above, once the screw is manufactured, the shape of the resin flow path in this part cannot be changed without changing the raw material supply cylinder or the screw shape. When trying to change the supply capacity of the screw, it is necessary to change the frictional force between the inner surface of the cylinder 2 and the resin or between the outer surface of the screw and the resin. In other words, in this case, it is normal to change the temperature of the cylinder or screw, but
The control range was far from sufficient.

In particular, in a plasticizing device having a cylinder structure having the group described above, in which the inner surface of the cylinder 2 is grooved, it is currently difficult to delicately control the feeding capacity by changing the temperature of the cylinder or screw. . One of the reasons for this is that in the case of a cylinder with a circular inner wall surface, the frictional force between the resin and the cylinder acts between the resin particles and the metal plane.
Although it is greatly affected by the friction surface temperature, in a cylinder structure having grooves 4 on the inner surface, the convex portion 7 of the groove shown in Fig. 6 receives the same effect as a circular sleeve, but the groove 4 portion When it comes to friction between resins, the friction surface temperature is less affected by the cylinder temperature than the former.

As described above, it is difficult to change the resin supply capacity in conventional plasticizing equipment, so once the resin passage in the raw material supply section is fixed in a specific shape by the structure of the screw and cylinder, it is difficult to change the resin supply capacity in conventional plasticizing equipment. When trying to plasticize raw materials with different shapes, apparent specific gravity, etc., the supply capacity cannot be adequately controlled.
Problems such as poor plasticization, fluctuations in the amount of plasticization, and poor dispersion of extrudates often occurred.

For example, in the case of a granulation extruder for resin raw materials mixed with inorganic fillers, increasing the pressure in the plasticizing section will cause agglomeration of the inorganic fillers, resulting in poor dispersion of the extrudate; conversely, lowering the pressure to reduce the supply of raw materials will cause This will reduce production capacity and cause fluctuations in the amount of extrusion. In general, the mixture ratio of fillers and the shapes and types of fillers and resins often differ, and it is often difficult to maintain an appropriate supply capacity for these raw materials while changing the temperature conditions of the cylinder. be. Therefore, in such cases, a raw material supply feeder is often installed separately to continuously supply a measured amount of the raw material to the plasticizing device.

The above-mentioned plasticizing equipment having a supply section with vertical grooves machined on the inner surface of the cylinder has a larger supply capacity than a cylinder with a circular inner surface, so it is becoming widely used, but the supply capacity becomes excessive. , the cylinder internal pressure becomes abnormally high, resulting in poor plasticization, fluctuations in the amount of plasticization, or clogging of the resin in this supply section, which may cause the extrusion amount to decrease and overload to occur. be.

(Problems to be Solved by the Invention) As mentioned above, in conventional plasticizing equipment of this type, once the cylinder and screw are combined, it is difficult to change them. In order to change the supply capacity, it is necessary to change the temperature of the cylinder and/or screw or the amount of raw material supplied. However, even with such means, it is difficult to obtain an appropriate supply capacity, which inevitably causes problems such as poor plasticization, fluctuations in the amount of plasticization, and poor dispersion of the extrudate.

The present invention solves these problems and allows for different types and types of raw materials.
The object is to provide a plasticizing device whose supply capacity can be easily adjusted depending on the shape and the like.

(Means for solving the problem) In a plasticizing device such as a plastic extruder or a rubber extruder, which performs plasticizing operation at a predetermined position in the axial direction of the screw, within a cross section including the axis of the screw in the raw material supply section. This problem is solved by having a screw in which the cross-sectional area of the resin flow path between the flights changes along the axial direction, and by moving the screw back and forth, the area of the resin flow path in the raw material supply section can be varied. It is intended as a means for

(Function) Resin flow between flights within a cross section that includes the axis in the axial direction of the raw material supply section of a plasticizing device that performs plasticizing operation at a predetermined position in the axial direction of the screw of a plastic extruder, rubber extruder, etc. Screws with varying cross-sectional areas are arranged, and the screws are moved in the axial direction to an appropriate position and fixed depending on the type and form of the raw material. By doing so, the cross-sectional area of the resin flow path in the supply section can be selected and adjusted to the optimum one according to the raw material, and it is possible to always exhibit an appropriate supply capacity.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 1 shows one embodiment of the present invention, and in the figure, 2 is a cylinder, 3 is a raw material supply port, and 4 is a groove that gradually decreases toward the tip of a screw 5 machined on the inner surface of the cylinder. . In this embodiment, the screw groove depth of the screw 5 gradually increases toward its tip, and therefore the resin flow path area also gradually increases toward its tip. In the figure, 5a represents a flight, and α represents the angle formed by the axis of the screw and the tangent to the groove surface of the screw. The screw 5 is constructed so as to be movable back and forth along its axis, as indicated by arrow 9 in the figure, and can be fixed to the machine base at a desired position. As this moving and fixing means, known means can be employed.

2 to 4 show other embodiments, and a second embodiment is shown in FIG.
In the figure, the pitch P between the flights 5a of the screw 5 is gradually increased toward the tip of the screw 5, and in this case, the cross-sectional area 6 of the resin flow path is also gradually increased toward the tip of the screw 5.

In the example shown in FIG. 3, the groove depth of the screw 5 is gradually decreased toward the tip of the screw 5, contrary to the example shown in FIG. The cross-sectional area 6 of the flow path gradually decreases toward the tip of the screw 5. Furthermore, in the example shown in FIG. 4, the groove depth of the screw 5 is changed stepwise, and in this example, the groove depth of the screw 5 is deepened in steps toward the tip of the screw 5. It is. In this case, the cross-sectional area 6 of the resin flow path increases stepwise toward the tip of the screw 5.

In all of these embodiments, like the embodiment shown in FIG. 1, the screw 5 is movable in the axial direction of the screw 5 and can be fixed to a machine base or the like at a desired position.

Although not shown, it is of course possible to reverse the structure of the screw 5 shown in FIGS. 2 to 4 in addition to these examples.

With this configuration, if you want to optimize the resin flow path area in the supply section depending on the type and form of the raw material, you can move the screw 5 back and forth along the axis. When the optimum position is reached, the screw 5 can be fixedly set on the machine base or the like.

(Effects of the Invention) As explained in detail above, the present invention provides a screw shaft in a raw material supply section of a plasticizing device that performs plasticizing operation at a predetermined position in the axial direction of a screw, such as a plastic extruder or a rubber extruder. The cross-sectional area of the resin flow path between the flights in the cross-section including The resin supply capacity can be adjusted by changing the setting position depending on the type and form of the resin. Therefore, it is possible to easily adjust the raw material supply capacity according to the type of resin without replacing the screw, which brings about extremely excellent effects.

[Brief explanation of drawings]

1 to 4 are side sectional views of a raw material supply section in a plasticizing apparatus showing different embodiments of the present invention, FIG. 5 is a side sectional view of a conventional raw material supply section, and FIG. 6 is a side sectional view of a conventional raw material supply section. It is a sectional view taken along the line A-A of FIG. Explanation of the main parts of the diagram, 2...Cylinder, 4...
Groove, 5... Skrill, 5a... Flight, 6...
Cross-sectional area of resin flow path.

Claims (1)

[Claims] 1 In a plasticizing device such as a plastic extruder or a rubber extruder that performs plasticizing operation at a predetermined position in the axial direction of the screw, the cross-sectional area of the resin flow path between the flights in the cross section that includes the axis of the screw in the raw material supply section. but,
A plasticizing device characterized by having a screw that changes along the axial direction, and moving the screw back and forth to change the cross-sectional area of the resin flow path in the raw material supply section.