JPS5914066Y2 - Screw-type compression dewatering extrusion device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a novel press-dehydration extrusion device with a screw.

Conventionally, resins that contain a large amount of liquid components such as water, such as resins polymerized in aqueous systems, are molded using a screw extruder after removing the liquid components using an airflow/fluidized dryer. However, in the drying process, the liquid components are vaporized and removed, resulting in not only thermal loss but also problems such as accelerated thermal deterioration of the resin.

In addition, as has become noticeable in recent years, we pursue high added value,
When high-mix low-volume production is carried out in the same process, it is predicted that contamination remaining in the drying process when changing types will reduce productivity.

In the rubber industry, compression dehydration has been put into practical use as part of the solution to these problems, but the water content is large, around 50% WB, and a large filtration area is required. The water that cannot be compressed and dehydrated is removed by vaporization through a vent mechanism installed between the first and second stages, and melt-forming, vulcanization, etc. are performed in the second stage. The structure of the liquid removal section is also complicated, which has the disadvantage of increasing the size of the device.

In addition, when such compression dehydration is applied to raw materials with low water content, such as water-based polymerized resins, the amount of water removed by compression dehydration is small, and the rubber industry may not exhibit any advantages.

As a result of intensive research in order to solve these problems, the inventors of the present invention and others have developed a method that is relatively free of water by providing a compression dehydration zone in a portion corresponding to the feeding section and heating melting section of a conventional screw extruder. We have discovered that compression dewatering can be carried out so efficiently that it can be applied to resins with a small amount of water, and have completed the present invention.

In other words, the gist of the present invention is to provide a dewatering section in a portion corresponding to the middle between the raw material supply section of a conventional screw extruder and a heat melting section having a vent section, and to A plurality of holes are drilled through the peripheral wall at appropriate intervals, and rod-like objects are removably inserted into the holes, and a liquid component is formed between the holes and the rod-like objects. A press-drying extrusion device with a screw set is characterized in that it has a slit that can be passed through.

To explain the present invention based on an embodiment, FIG. 1 is a partial vertical sectional side view of a device showing an example of the present invention, FIG. 2 is an enlarged vertical sectional side view of section A in FIG. 1, and FIG. In FIG. 2, a dehydration section is provided in a portion corresponding to the middle between the raw material supply section of a normal screw extruder and the heat melting section having a vent section 7, and the peripheral wall of the barrel 2 in the dehydration section is A plurality of holes 10 are drilled through the peripheral wall at appropriate intervals, and a female thread is provided in the L1 portion of the hole 10 on the barrel inner surface 11 side, and the female thread is in a state where play occurs. The bolt 3 is removably screwed onto the barrel outer surface 12 side, and the inner diameter of L2 on the barrel outer surface side of the hole 10 is the bolt 3.
Most of the liquid components removed from the raw material in the dewatering section are formed by the slit formed by the backlash in the threaded part between the female thread and the bolt, and the L2 part of the hole 10 and the bolt 3. It is designed to be discharged outside the barrel through an annular slit formed between the two.

FIG. 3 is an enlarged longitudinal sectional side view showing another example of section A in FIG.
) and the upper part of hole 10' (L '2 + L '3
The bolt 3' is screwed into the hole 10' by cutting a thread only in the part ( ), and a part of the threaded part of the bolt 3' is scraped off in the direction of the screw axis like a tap, so that the material inside the barrel is not removed. The liquid component that came out flows through the annular slit formed between the lower part of the bolt 3'(L't + L' 2 parts) and the hole 10, and the hole 10.
and a slit formed by the threaded portion of the bolt 3', and are discharged out of the barrel.

As mentioned above, the feature of this device is that it has a specific structure between the feeding section of a normal screw extruder and the heating melting section with a vent section to remove liquid components such as water contained in the raw materials. However, as mentioned above, when the amount of liquid components contained in the raw material is large, a large filtration area is required, so the dehydration section is installed between the supply section and the heating melting section. If the screw is installed, the total length of the extruder becomes very long, which causes problems in terms of the strength of the screw, but for raw materials with a small liquid component, the filtration area, that is, the length of the dewatering section, can be made relatively short, and the length of the extruder increases. The overall length can also be kept to a level that is not much different from what is normally used.

Furthermore, by providing the dehydration section in a portion corresponding to the raw material supply section and the heating melting section of a conventional screw extruder, it is possible to produce effects that cannot be obtained by ordinary compression dehydration.

Simple compression dehydration cannot reduce the amount of liquid components contained in raw materials to zero within the range of practical compression pressure.
The remaining liquid components must be heated and vaporized and removed from a vent or the like.

In this device as well, a vent section is provided in the heat-melting section to remove residual liquid components, but at this time, an amount of liquid components that exceeds the amount of liquid components removed by simple compression dehydration is removed from the dehydration section. The amount of liquid components vaporized and removed from the vent section is reduced.

There are many possible causes for this, but it is likely that some of the liquid components vaporized in the heating and melting section flow to the dehydration section, come into contact with the newly supplied raw material at a relatively low temperature, and condense. It is thought that it is removed in a more liquid form.

In this way, this device acts as if it had a kind of heat exchanger inside, and there is very little heat loss due to vaporization of liquid components.

Furthermore, since the amount of liquid component contained in the resin introduced into the vent part is small, the volumetric expansion of the molten resin due to foaming of the liquid component is small, and troubles such as venting are less likely to occur, making it possible to avoid problems such as venting. It is possible to obtain a discharge amount comparable to that of an extruder.

As mentioned above, by simplifying the structure of the dewatering section and downsizing the device, this device, which is about the same size as the screw extruder used in the conventional process, can perform the conventional drying process and melt extrusion process. It is possible to replace the molding process.

Furthermore, the benefits of introducing this equipment are immeasurable, including increased production efficiency through process simplification, reduced capital investment, and energy savings through reduced thermal loss.

Furthermore, compared to a process that includes a drying step, the thermal history of the raw material resin is shortened, and the effect of reducing thermal deterioration can be expected.

[Brief explanation of the drawing]

Figure 1 is a partial vertical side view of a device showing an example of the present invention, Figure 2 is an enlarged vertical side view of section A in Figure 1, and Figure 3 is another example of section A in Figure 1. 1 to 3, 1 is a hopper, 2 is a barrel, 3 and 3' are bolts, 4 is a cooling jacket, 5 is a cooling jacket refrigerant inlet, and 6 is a cooling jacket refrigerant outlet, 7 is a vent part, 8 is a heater, 9 is a female thread part, 10.10' is a hole that passes through the barrel, 11 is an inner surface of the barrel, 12 is an outer surface of the barrel,
13 is Screw.

Claims (1)

[Scope of utility model registration request] A dehydration section is provided in a part corresponding to the middle between the raw material supply section of a normal screw extruder and a heat melting section having a vent section, and the peripheral wall of the barrel in the dehydration section is penetrated at an appropriate interval. The screw is characterized in that a plurality of holes are formed in the hole, a rod-shaped object is removably inserted into the hole, and a slit through which a liquid component can pass is formed between the hole and the rod-shaped object. Complete set of compression dewatering extrusion equipment.