JPH0647253B2 - Kneading machine for thermoplastic resin and water or additives - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to water, which is a necessary auxiliary agent for removing residual monomers in a molten thermoplastic resin (hereinafter simply referred to as “resin”) in a thermoplastic resin production process. Alternatively, it relates to a kneader for efficiently and continuously kneading and dispersing the additives.

[Prior Art] An example of a conventional kneader will be described with reference to FIG. Barrel 11
The screw 12 rotatably inserted in the
It is composed of a full-flight screw 13 and a dullage screw 14 each having a relatively small D, and a screw 15 (hereinafter, this screw is referred to as a unimelt screw) alternately arranged in opposite directions so as not to communicate the first groove with the first groove. ing.

The resin sent from the injection pipe 16 on the right side of the barrel 11 is pressurized by the full flight screw 13, and the layer is divided by the dullage screw 14, where water or the like is injected into the injection port 1.
Injected from 7. Next, in the unimelt screw, when moving from one groove to the adjacent groove, the resin and water are kneaded and dispersed by receiving a shearing force in the gap with the barrel 11. In this method, the pressure is increased by the full-flight screw 13 for the original purpose of kneading and dispersing the resin and water, so that several times as much power is required as compared with the method without this, which is against energy saving.

In order to improve the drawback of FIG. 4 described above, a system has been proposed in which only the unimelt screw 21 is used as shown in FIG. 5, and the pressure of the resin is increased by a gear pump (not shown) installed in front of the kneader. . Since this system uses only a unimelt screw, its driving power is halved as compared with FIG.

However, this method is only for the unimelt screw 21, and here, in order to enhance the kneading dispersion of the resin and water etc., if the gap between the unimelt screw 21 and the barrel 22 is reduced or the unimelt screw 21 is lengthened, the resin pressure will be increased. The physical properties such as the impact value of the raw material are lowered because the shearing force is too high and the shear force is too high. On the other hand, if the gap is enlarged or the length is shortened, the kneading dispersion is deteriorated, and the kneading dispersion characteristics of the desired resin and water are deteriorated. In this method, water is injected in the middle of piping from the gear pump.

In each of the methods shown in FIGS. 4 and 5, the remaining monomer is removed in the next step.

[Object of the Invention] The present invention eliminates such drawbacks, and its object is to:
Another object of the present invention is to provide a kneading machine for a resin, water and the like, which has a high kneading and dispersing effect and has a small driving power and does not impair the physical properties of the resin.

[Points of the Invention] A kneader of a thermoplastic resin and water or an additive according to the present invention is provided with a barrel of the kneader and a rotating screw in the barrel to provide water or an additive during the plasticizing step of the thermoplastic resin. In a kneader of a thermoplastic resin and water or an additive for mixing and kneading, a screw shaft is provided between the resin inlet and the outlet of the kneader at a position corresponding to the water or additive injection port provided in the barrel. A cross screw having a protrusion formed on its surface, a multi-notch flight screw in which the screw flight is notched in the direction perpendicular to the screw shaft, and the rest has a protrusion, and the multi-notch flight screw. A pin protruding in the radial direction of the screw shaft at the position of the barrel corresponding to the cutout portion, and a unimelt screw alternately arranged in opposite directions so as not to communicate the leading groove grooves. It is characterized by having sequentially.

[Embodiment of the Invention] Referring to FIGS. 1 to 3 showing an embodiment of the present invention. The screw 32 in the barrel 31 is composed of a first-stage cross screw 33, a second-stage multi-notch flight screw 34, and a third-stage unimelt screw 35. The resin pressure-fed from the gear pump (not shown) in the previous stage comes into contact with the cross screw 33 in the first stage, and the kneading dispersion in the initial stage is performed in this portion. In this portion, water or an additive is injected into the resin from the injection pipe 36. Further, the cross screw 33 has a large number of pin-shaped projections 33A which are projected straight and obliquely arranged, and the flowing resin and water are kneaded and dispersed when they are divided into two directions by the pins 33A. Done.

In the next-stage multi-notch flight screw 34, a plurality of pins 37 are provided on the barrel 31 in two rows and in the circumferential direction at the notch portion of the flight. These pins 37 are notched in the flight as shown in FIG. The portion facing the portion has an oval shape, and the resistance force to resin or the like can be adjusted by rotating the pin 37 with respect to the axis. Therefore, the resin and the water and the like flow along the flight and then merge at the cutout portion, but since the pin 37 is provided in this portion, the resin and the water and the like are forcibly separated here and subjected to a strong shearing force. Kneading and dispersion are performed.

Subsequently, the resin and water and the like flow into the unimelt screw 35, and at this time, the resin and water and the like flow into the groove on one side, but since the groove is the first groove, the unimelt screw 35 and the barrel 31 It is forced to go over the gap with the inner diameter of, and flows into the adjacent groove with the tip open, and when it goes over this, it receives shearing force and is kneaded and dispersed. Since the barrel 31 facing the unimelt screw 35 is provided with a resin outlet pipe 38, the well kneaded and dispersed resin, water and the like are discharged from the outlet pipe 38 to a flash tank (not shown) for the next step. ) And residual monomers are devolatilized.

[Effects of the Invention] As described above, the kneading machine for the resin and water or the additive in the present invention has the screw as the first stage cross screw, the second stage multi-row notch flight screw and the third stage unimelt. A screw was used, and the resin, water and the like were kneaded and dispersed by the respective screws. In particular, in the second stage multi-notch flight screw, a pin is provided on the flight notch in the barrel so that the resin and water that have merged from the flight are forcibly divided by the pin to exert a shearing force.

Therefore, the resin, water, and the like are efficiently kneaded and dispersed while passing through the three-stage screw, and the residual monomer is surely volatilized when transferred to the flash tank in the next step. Further, the method of the present invention has energy saving efficiency in which the total driving force of the gear pump and the screw is halved as compared with the conventional method of FIG. 4, and has an advantage that the physical properties are not lost because it is not subjected to excessive shearing force. . There is also an advantage that the kneading effect can be adjusted by rotating the elliptical pin.

[Brief description of drawings]

1 to 3 show an embodiment of the present invention. FIG. 1 is a longitudinal sectional view, FIG. 2 is a sectional view taken along line 2-2 of FIG. 1, and FIG. 3 is 3-3 of FIG. Line sectional views, FIGS. 4 and 5 are vertical sectional views of conventional examples having different shapes. 31 ... Barrel, 32 ... Screw, 33 ... Cross screw, 34 ... Multiple notch screw, 35 ... Unimelt screw, 37 ... Pin

Claims (2)

[Claims] 1. A kneading machine comprising a barrel of a kneading machine and a rotating screw in the barrel and mixing water or an additive during the plasticizing step of the thermoplastic resin and kneading the mixture with the water or the additive. In the machine, between the resin inlet and outlet of the kneading machine, a cross screw having a protrusion formed on the surface of the screw shaft at a position corresponding to the water or additive injection port provided in the barrel, and then A multi-notch flight screw in which a screw flight is cut out in a direction perpendicular to the screw shaft and the rest is formed in a protrusion shape, and a barrel corresponding to the notch of the multi-notch flight screw is located at a position in the radial direction of the screw shaft. A mixture of a thermoplastic resin and water or an additive, which is sequentially provided with a protruding pin and a unimelt screw which are alternately arranged in opposite directions so as not to communicate with the first groove. Machine. 2. A kneading machine for mixing a thermoplastic resin and water or an additive according to claim 1, wherein the pin protruding in the radial direction of the screw shaft has an elliptical tip and is rotatable.