JPH0348842B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plasticizing and kneading device that directly supplies and molds resin and filler in a resin molding machine such as an extruder or an injection molding machine.

Direct composite forming, in which resin and filler are directly supplied and molded, requires that the filler be uniformly dispersed in the molded product, that the filler will not be damaged by cutting, and that stable plasticity be ensured to obtain a stable molded product. Furthermore, it is necessary that the filler causes less wear and tear on the molding machine.

A conventional device is shown in FIGS. 1 and 2. In the figure, 1 is a heating cylinder, 2 is a screw, 3 is a supply port for materials consisting of resin and filler, 4 is a hopper, 5 is a feeder, 6 is a vent hole, 7 is a supply zone, and 8 is a plasticization kneading zone. .

FIG. 1 shows a type in which a hopper 4 is directly connected to the supply port 3 without providing a feeder 5. Therefore, since the feed zone 7 is filled with the material consisting of resin and filler, the following disadvantages arise in direct composite formation.

(1) The material filling the screw groove in the supply zone 7 is compressed and forms a plug-like solid bed, so there is no relative movement between the filler and the resin inside the solid bed, and there is no movement of the filler and the resin from the inner wall of the heating cylinder 1 around the solid bed and the screw wall. The temperature can only be increased by heat conduction, and the mixture moves to the plasticizing and kneading zone 8 without being sufficiently preheated, causing instability in plasticizing, a decrease in capacity, and poor dispersion.

(2) As the screw groove is filled with material, propelling pressure is generated in the screw groove, and this pressure presses the fillers together, so
It is difficult to impregnate molten resin between fillers. This is because the higher the pressure, the more difficult it is to impregnate the molten resin between the fillers, causing poor dispersion and secondary agglomeration.

(3) Due to the propulsion pressure generated in the screw groove,
The solid bed is pressed against the inner wall of the heating cylinder 1 and melted by shearing action and heat transfer, but the higher the driving pressure, the greater the shearing force, and the more the filler is cut and damaged.

(4) As the screw grooves are filled with material, it becomes relatively difficult to discharge gas depending on the filler, and discoloration of molded products due to adiabatic compression of air between fillers due to generated pressure and oxidation. becomes more likely to occur.

FIG. 2 shows a conventional type of device with a feeder 5, which has the following drawbacks.

(5) Since the transport capacity of the feed zone 7 is much larger than the feed capacity being sent by the feeder 5, the material fed by the feeder 5 passes through the feed zone 7 in a short time and is not plasticized without sufficient preheating. Due to forced plasticization due to the transition to kneading zone 8,
Unstable plasticization, poor dispersion, and filler breakage are likely to occur.

(6) If the supply capacity is reduced in order to avoid excessive plasticization, the plasticization capacity will inevitably decrease.

The present invention eliminates these drawbacks and provides a plasticizing and kneading device that can improve filler dispersion, reduce cutting damage, and perform stable plasticizing.

Next, the present invention will be explained with reference to embodiments shown in the drawings.

3 to 6 show an embodiment of the present invention, in which a screw 2 which is rotatable or rotatable and slidable in the axial direction is disposed inside a heating cylinder 1, and the heating A feeder 5 is provided in the feed hole 3 of the cylinder 1, and a feed zone 7 and a plasticization kneading zone 8 are provided in the screw 2 from the feed hole side.
Notches 12 are provided in the screw flights 11 of the compression zone 10 and the supply zone 7 where the screw groove depth 9 changes.
has been established. The notch 12 has a constant notch area in the supply zone 7, and is provided in the compression zone 10 so that the notch area decreases as the screw groove depth 9 becomes gradually shallower from the direction of the supply zone 7. FIG. 4 shows an enlarged view of the screw 2 part, and FIGS. 5 and 6 show longitudinal sections. The area of the notch 12 varies depending on the type of resin and filler, the mixing ratio, the shape of the resin pellets, etc., but is set to be about 10 to 30% of the cross-sectional area of the screw groove 13, for example.

The effects of the present invention will be explained in detail. Originally, the material supplied from the feeder 5 has a large transportation capacity of the screw 2 in the supply zone 7.
It passes through the supply zone 7 in a short time. However, according to the present invention, the transport capacity of the feed zone 7 is reduced by the notch 12, and the filler and resin are mixed just inside the tumbler while maintaining free space in the screw groove 13 of the feed zone 7. As in the mixing of the materials in , the materials are mixed by the rotation of the screw 2 , and the materials are heated while contacting the inner wall of the superheating cylinder 1 and the screw wall of the screw 2 until all parts of the materials are mixed, and the materials are heated in the plasticizing kneading zone 8 . Move slowly to the compression zone 10.

Therefore, as shown in the example of FIG. 1, in the process in which the screw groove 13 is filled with material and the material moves from the supply zone 7 to the plasticizing and kneading zone 8, as shown by a in FIG. The pressure in the heating cylinder 1 is high, so that a solid bed is formed, the material is hardened, and the filler in particular is not compressed, making impregnation with the softened molten resin difficult. That is,
The temperature of all parts of the material rises slowly and uniformly, and the temperature of both the filler and the resin rises, and at the start of softening and melting, when the resin has a free boundary surface in the screw groove 13, it melts and softens the resin. The filler is mixed freely, or the molten resin is impregnated between the fillers.
There is no case of insufficient preheating as in the case shown in FIG. In addition, since the material is transported while having a free boundary surface in the supply zone 7, there is no pressure or only a small amount of pressure, and there is little chance of cutting or damaging the filler. 1
1. There is also less wear. In this way, the resin and filler are uniformly heated to a temperature immediately after the resin softens and melts, moves to the plasticizing and kneading zone 8, and is gradually and effortlessly processed in the compression zone 10, where the passage cross-sectional area gradually narrows. In this process, while eliminating air in the material, the filler and resin are not subjected to excessive shearing action under low pressure due to the rotating action of the screw 2, and the mixing action at the notch 12 is also added. It is being kneaded. The notch 12 provided in the compression zone 10 gradually becomes shallower as the screw groove depth 9 advances forward, as shown in FIG. Prevents reduction in transport capacity due to leakage flow. Furthermore, as shown as d in Fig. 7, since the absolute value of the pressure is small, cutting and damage of the filler is reduced, and local excessive rise in resin temperature is eliminated.
Since the viscosity is relatively constant and the viscosity is high, the filler is dispersed well and there is little discoloration of the molded product. The advantage is that there is less wear on the heating cylinder 1 and screw light 11, and gas corrosion is also less due to no excessive rise in resin temperature, although this differs depending on the resin.

The filling rate of the material in the screw groove 13 space in the supply zone 7 is preferably about 40 to 70% from the viewpoint of free movement of the material in the screw groove 13 and degassing.

The notch area provided in the screw flight 11 may be reduced as it advances forward in the compression zone 10 parallel to the axial direction, as shown in FIG. A notch may be made in the direction of the opposite thread to the Euphrite 11, and the notch area may decrease as it advances forward. Note that the two-dot chain line indicates a state in which the area of the notch 12 is gradually reduced.

In the embodiment shown in FIG. 10, instead of providing the feeder 5, the supply zone 7 is divided into a first supply zone 14 and a second supply zone 15.
The screw pitch or the screw groove depth of No. 4 is made smaller than that of the second supply zone 15,
The above-mentioned effect can be obtained by reducing the transport capacity of the first supply zone 14 and preventing the second supply zone 15 from being completely filled with material.

In this way, in the present invention, the notches are provided in the screw flights in the supply zone and the compression zone, so it is possible to improve the feeding condition of the material, improve the dispersion of the filler, and reduce breakage of the filler due to cutting. . In addition, because plasticization and kneading are performed under low pressure, wear on the heating cylinder caused by the filler can be reduced.
Under a good temperature without excessive rise in resin temperature,
Good plasticization and kneading without gas corrosion can be performed. Therefore, it becomes possible to easily obtain a molded product of good quality.

[Brief explanation of drawings]

1 and 2 are vertical cross-sectional views showing different examples of conventional devices similar to the present invention, FIG. 3 is a vertical cross-sectional view showing one embodiment of the present invention, and FIG.
Figures 5 and 6 are partially enlarged views of Figure 4, respectively. 8 and 9 are developed views showing other embodiments of the present invention, and FIG. 10 is a longitudinal sectional view showing still another embodiment of the present invention. 1... Heating tube, 2... Screw, 3... Supply hole, 5... Feeder, 7... Supply zone, 8...
Plasticization kneading zone, 10... Compression zone, 11...
... Screw flight, 12 ... Notch, 13 ... Screw groove.

Claims (1)

[Scope of Claims] 1. A screw that is rotatable or rotatable and slidable in the axial direction is installed inside the heating cylinder, and a supply zone and a plasticization kneading zone are provided in the screw from the supply hole side of the heating cylinder. , a notch is provided in the screw flight of the compression zone where the screw groove depth of the supply zone and the plasticization kneading zone changes, and the notch area in the compression zone decreases as the screw groove depth gradually becomes shallower. A plasticizing and kneading device was installed. 2. The plasticizing and kneading device according to claim 1, wherein a plurality of rows of notches provided in the screw light are provided in parallel in the axial direction. 3. The plasticizing and kneading device according to claim 1, wherein the notch provided in the screw flight is provided in a thread direction opposite to the direction of the screw flight. 4. From the supply hole side to the supply zone, enter the first supply zone,
The plasticizing kneading according to any one of claims 1 to 3, wherein a second supply zone is provided, and the transport space of the screw groove is smaller in the first supply zone than in the second supply zone. Device.