JPS6017304Y2 - single screw extruder - Google Patents

Description

[Detailed description of the invention] This invention relates to a single-screw extruder screw, and its purpose is to improve the mixing and kneading performance of raw materials in the single-screw extruder screw without reducing its extrusion rate. It is something.

Single-screw extruders tend to be used more often than multi-screw extruders such as twin-screw extruders due to their advantages such as simple structure, durability, and low cost. In the past, its use was mainly limited to extruding general-purpose thermoplastic resins.

On the other hand, recently there has been a strong demand for high-speed extrusion molding of high-quality products, but it has been thought that using a single-screw extruder is insufficient to meet this demand.

That is, with the conventional single-screw extruder, it was difficult to obtain a uniform plasticized and molten state of the raw material resin, so it was difficult to obtain a good product.

In order to improve the performance of a single-screw extruder, it is important to provide sufficient mixing and kneading effects to the raw material resin, and to have the ability to uniformly plasticize and melt it. , various screw kneading mechanisms have been proposed.

In most of these, a resistor having no propulsive force is interposed in the resin flow path, thereby causing a delay in resin transfer.

However, even if this is done, not only is it not possible to obtain sufficient mixing and cross-contact conditions, but it also causes a new decrease in the extrusion rate, which goes against the goal of increasing extrusion speed and capacity, and may also cause changes in the physical properties of the raw material resin. .

This invention was created in view of the above, and simultaneously achieves higher speed, higher capacity, and higher product quality in a single-screw extruder, and its application is limited to conventional extrusion molding of thermoplastic resins. First, we propose a single screw extruder that can be fully applied to composite materials with different viscosities and shapes, as well as thermoplastic resins containing fillers and additives.

An example of the present invention will be explained below based on FIGS. 1 to 4.

In FIG. 1, 1 is a screw, 2 is its rotating shaft, and 3 is a screw blade.

The base end of the screw 1 is a feeding part F1 of raw resin.
The end portion acts as the metering portion M, and the intermediate portion thereof functions as the resin mixing and kneading portion A.

In other words, the screw blade 3 is located at the right place in this middle part.
is cut out, and a polygonal portion 4 is formed in that portion.

As is clear from FIGS. 2 to 4, the polygonal portion 4 is divided into a first half 4A and a second half 4B, and the second half 4B is continuous with the first half 4A via a widening portion 4C.

Each ridge 5A, 5B in the front half 4A and the rear half 4B
has a constant width S1. S2 stripes 6A, 6B are formed, and their widths S1. S2 is set to the relationship SL<32.

One blade body 8A is provided on the outer surface 7A between each of the ridges 5A and 5B in the front half 4A along the diagonal line so that the lead angle is 01 degrees.

A plurality of notch grooves 9A are formed on the outer periphery of these blade bodies 8A at regular intervals in the axial direction thereof.

On the other hand, on the outer surface 7B between the respective ridges 5B in the rear half 4B, and on the outer surface 7A that continues from the outer surface 7B to the outer surface 7B via the widening section 4C, one sheet each is placed so that the lead angle is 02. A blade body 8B is provided.

Note that θ, >θ2. And the outer circumferential surface of the front half blade body 8A, the front half striped surface 6A, and the rear half blade body 8B.
The outer circumferential surface and the rear half striped surface 6B are configured to be on the same virtual cylindrical surface, respectively, and the front half blade body 8A
The outer diameter D1 of the rear blade body 8B and the outer diameter D2 of the rear wing body 8B are Dl<D
2 Also, the groove depth hl between the outer surface 7A of the front half and the outer surface of the blade 8A and the groove depth h2 between the outer surface 7B of the rear half and the outer circumferential surface of the blade 8B are set to have a relationship of hl>h2. be done.

In the above, the resin P sent to the mixing and kneading section A is rotated around the axis of the front half blade body 8A or the rear half blade body 8B so that its lead angle θ1. It moves forward along the blade bodies 8A and 8B in accordance with θ2, but a part of it relatively climbs over the notch groove 9A of the front blade body 8A and its outer peripheral surface, or the outer peripheral surface of the rear blade body 8B. , and then moves over each strip surface 6A, 6B onto the adjacent outer surface 7A, 7B, and the same action is repeated.

That is, the resin flow is dispersed into a forward flow and a branch flow;
The merging of the two is repeated alternately.

Due to this behavior, a high degree of dispersion, mixing action, and kneading action are achieved, and the resin is brought into a uniform plasticized and molten state.

As shown in FIG.
Providing it close to the metering section M facilitates kneading and leveling of the resin, or homogenizing the product, and conversely, by providing it close to the feed section F, it improves dispersion and mixing effects in the composite material. will improve.

Furthermore, in either case, the divided flow rate of the resin increases due to the effect of the notched groove 9A of the front half blade body 8A, so that the mixing and kneading effects become remarkable.

In the illustrated example, D□<D2. Sl<S2. θ1〉θ2?
h, > h2, but if this is done, the resin will flow smoothly into the mixing and kneading section A, and in the first half 4A, even the resin with high viscosity after the start of melting will be uniformly mixed and kneaded. be done.

On the other hand, in the second half 4B, a high shearing action, that is, a high kneading action is applied to the resin due to the above relationship, so the unmelted substances floating in the molten resin are effectively melted, and homogenization is promoted. be done.

Furthermore, each blade body 8A, 8B has a lead angle θ0. θ
2, it does not cause the resin to flow backwards or prevent its flow, but instead provides a propelling action to the resin.

As is clear from the above description, the present invention is a single-screw extruder screw inserted into a cylinder with a cylindrical space inside, unlike the extruder screw inserted into a cylinder with a polygonal space inside. There is no need to require considerable engineering skills for the cylinder, and costs can be kept low.

In addition, the intermediate part formed at the middle part of the rotating shaft is divided into a first half and a second half, and a blade body with a plurality of notched grooves formed on the outer periphery is provided on the outer surface of the first half, and a blade body is provided on the outer surface of the second half. Since the blades are provided on the outer surface of the front half, the action of the blades and the notched grooves in the front half increases the amount of resin diverted and mixes the resin.
While it is possible to make the kneading effect more pronounced, the blades in the latter part give a high shearing action (kneading action) to the resin and effectively homogenize the unmelted material floating in the molten resin. can be encouraged.

Furthermore, the lead angle θ1. Since θ2 is provided, a propulsion effect can be given to the resin without causing the resin to flow backward or blocking the flow.

Therefore, the extrusion capacity of the single-screw extruder screw can be maintained at the same level or higher than that of conventional extruders, and a uniform plasticized molten state of the raw material can be obtained.

Therefore, it can be distantly related to the recent improvements in capacity, speed, and product quality of extrusion molding for various raw materials.

In the illustrated example, a hexagonal polygonal portion 4 is shown, but the number of corners can be changed depending on the type of raw material, etc., and the number of blade bodies 8A, 8B, The shape can also be varied.

[Brief explanation of the drawing]

Figures 1 to 4 show an embodiment of the present invention, with Figure 1 being a schematic side view, Figure 2 being an enlarged side view of the main parts, and Figure 3 being the second embodiment of the invention.
FIG. 4 is an enlarged perspective view of the main part. 1... Screw, 2... Rotating shaft, 4
...Polygonal part, 4A...First half, 4
B: Second half, 4C: Spreading part, 5
A, 5B... Edge, 6A, 6B... Strip, 7A, 7B... Outer surface, 8A, 8B...
...Blade body.

Claims (1)

[Scope of utility model registration request] This is a single-screw extruder screw inserted into a cylinder with a cylindrical space inside, and is divided into a front half and a rear half at the middle of the rotating shaft, and the latter is continuous with the front half through a widening part. One blade is provided on the outer surface between the ridges in the first half of the polygon with a lead angle of 01, and the outer periphery of these blades is A number of notch grooves are formed at regular intervals on the part, while on the outer surface between each ridge part in the rear front half of the polygonal part,
and one blade body is provided for each blade body so that the lead angle is θ2, which is smaller than the lead angle θ1 of the blade body, from the outer surface to the outer surface between the ridges of the front half part that are continuous to the outer surface via the widening part. A single screw extruder characterized by: