JPS61209124A - Kneading screw for single screw extrusion - Google Patents

Abstract

PURPOSE:To enable to highly efficiently extrude favorable extrudate by a structure wherein a kneading section, in which multiple forward flights and multiple backward flights are opposedly arranged on both sides of a plane containing the axis center line of a screw so that both ends of each flight of the forward or backward flights locate corresponding to the groove between the flights of the other multiple flights. CONSTITUTION:Solid raw material supplied to a cylinder is pre-heated at a supplying section A, transferred to a fusing section B and, after being fused, sent to a metering section C so as to enter in a kneading section D. At the kneading section D, fused body is transferred forwards and simultaneously kneaded by the tractive flow developed with the rotation of a kneading screw 1 in forward screw grooves 16, 17, 18, 19 and 20. Further, the fused body is similarly transferred backwards and simultaneously kneaded in backward screw grooves 21, 22, 23, 24 and 25. Thus, while being repeatedly or at least twice subject to kneading action with fused bodies in the screw grooves before and after in one screw groove, the fused body is transferred forwards and finally extruded while being uniformized in a screw groove 3, which is made by a flight 2 formed at the tip of the melting section.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a single-wheel extrusion cross-contact screw, suitable for cross-contact of thermoplastics, composite materials of thermoplastics and fillers, ceramics, and foods. This invention relates to a mixed screw for single-screw extrusion.

[Conventional technology]

Generally, in a mixed screw for extrusion, a shearing action acts on the melt as the screw rotates, and as a result, the melt is homogenized and extruded by the mixed wire action. Conventionally, this mixed wire screw In order to improve the crosstalk effect, so-called barrier type screws, which have a narrow gap in a part of the flow path, have been widely used.This barrier type screw allows the molten material to pass through a narrow gap by forcing it to pass through a narrow gap. The idea is to apply a strong shearing action to the body, thereby improving the crosstalk effect.

In addition, as another conventional means for improving the crosstalk effect, a so-called oxing type screw, in which a protrusion is installed in the screw groove of the crosstalk screw, is also frequently used.

This mixing type screw uniformizes the melt by forcibly separating and merging the melt using protrusions.

[Problem that the invention seeks to solve]

Conventionally used barrier type screws and mixing type screws have the above-mentioned configuration and function, but
Each of them has the following problems.

First, in the barrier type screw, the barrier part acts as a flow path resistance, which causes problems such as generation of high pressure, increase in temperature of the melt, and decrease in extrusion rate.
Therefore, there is a limit to the improvement in the crosstalk effect.

In addition, in the mixing type screw, the melt is divided in the flow direction, but the number of divisions is small, and there is a problem in that it cannot be expected to exchange the positions at all between the front and rear flow paths. Therefore, the crosstalk effect cannot be improved beyond a certain level.

In order to improve the kneading effect, it is necessary to repeatedly exchange the position of the melt. This invention was made to solve the above-mentioned problems. The purpose of the present invention is to obtain a cross-contact screw for extrusion that can extrude a good extrudate with high efficiency by improving cross-contact action by changing the position without causing pressure generation, temperature increase, or decrease in extrusion rate. It is something.

[Means for solving problems]

The single screw for extrusion according to the present invention is a single screw in which a supply section, a melting section, and a metering section are arranged from the root side. The multi-flight flights and the multi-flight flights discontinuously formed in the opposite direction for transporting the mixed material rearward are arranged to face each other on both sides of the plane including the axis of the screw, and the multi-flight flights in both directions At least one kneading section is provided in the portion constituting the melting section and the measuring section, and both ends of the kneading section are arranged so as to correspond to the grooves between the multiple flights.

[For production]

Since the single screw for extrusion according to the present invention is configured as described above, by the rotation of the screw, for example, the mixed wire material that has been kneaded and extruded between the forward multi-flights and reached the end can be At this point, it is divided into two parts by the reverse multi-flight flight, enters the grooves on both sides of the reverse multi-flight flight, and is fed back and kneaded. In this case, each of the crosstalk materials in the adjacent grooves of the forward multi-threaded flight is divided into two, and one of the two enters the seven grooves, so the positions are exchanged, and This is done every half turn for each row, resulting in extremely large positional changes.

〔Example〕

Hereinafter, the present invention will be explained based on the drawings showing one embodiment thereof.

In FIG. 1, the extrusion mixed screw/constitutes a supply section A, a melting section B, and a measuring section C from the root side, and the kneading section is installed in the measuring section C.

The details of this kneading section are shown on the right side of Figure 1,
The kneading section has a forward multi-row fly formed in the forward direction that transports the melt forward.

9, and a reverse multi-filament flight 10 formed in the opposite direction to transport the molten material backwards. //, 12. /J, /da.

15, each forward and reverse multi-strip flight) l-/, t is discontinuous, and the forward multi-strip flight da~de and the reverse multi-strip flight 70~l! are arranged opposite to each other with respect to -m on the plane containing the axis of the cross-conductor screw /, and the forward direction multi-thread flight leader ~
The start and end points of TE are reverse multi-line flights 10-/! The screw grooves are arranged to correspond to the screw grooves formed between adjacent ones of the screw grooves. Also, reverse multi-strip flight lO~l! Similarly, the starting point and the ending point are arranged so as to correspond to the screw grooves formed between adjacent forward multi-thread flight starters. In addition,
Forward multi-strip flight 10 and reverse multi-strip flight 10
/! The r leads are formed uniformly. In addition, the sign λ
indicates a flight, and 3 indicates a screw groove.

This embodiment is constructed as described above, and its operation will now be explained.

The solid raw material supplied to the cylinder is transferred while being preheated by the supply section A and reaches the melting section B, where it is melted and then sent to the measuring section C and then enters the kneading section.

Here, the melt transferred to the starting end of the kneading section is transferred to the forward screw groove formed between the forward multi-thread flights y to d. /7. /I, /q, in 20, crosstalk screw l
The mixture is transported forward and kneaded by the traction flow caused by the traction force caused by the rotation of the . Also, following this, reverse multi-strip flight 10-/! Reverse screw grooves formed between 1, -1, λ3. In the -da and λj, the mixture is similarly transported rearward by the traction flow caused by the rotation of the mixing screw/, and is kneaded. Note that the length of this kneading section is set depending on the required degree of kneading.

Next, forward multi-strip flight Hiro-de and reverse multi-strip flight 1
0~/! We will explain the flow of molten resin between r and 7 lights as an example.
The molten material in A is sent forward by the rotation of the kneading screw l, but is divided into two parts by the reverse direction multi-flight // and is transferred into the reverse direction screw grooves C/ and 2. Similarly, the molten material in the forward direction screw groove/2 is also divided into two by the reverse direction multi-flight flight/2 and transferred into the reverse direction screw groove here and 23. Therefore, the melt in the reverse screw groove here is a mixture of the melt transferred from the forward screw groove /6 and the melt transferred from the forward screw groove /7. Note that the homogenization of the melt is performed by circulating flow due to traction force.

Similarly, the molten material in the reverse direction screw groove 23 is in a state in which the molten material transferred from the forward direction screw grooves L and /S is mixed.

On the other hand, the molten material in the reverse direction screw groove 2 is divided into two by the forward direction multi-thread fly) j-, and the melt in the forward direction screw groove 16
and 77, and similarly, the reverse direction screw groove-3
The molten material inside is divided into the forward screw groove/it and transferred.

Thus, for example, the melt in the forward screw groove /7 is equal to the melt transferred from the reverse screw grooves Coco and CoJ, i.e., the forward screws @/A, /7 and /7.
The melts transferred from j are in a mixed state.

The above description has been made using seven forward screw grooves as an example, but the same operation is performed for all of the forward screw grooves and reverse screw grooves.

In this way, within the kneading section, the molten material is transferred forward in the screw grooves while being repeatedly cross-contacted with the molten materials in the front and rear screw grooves one or more times.

The molten material sufficiently kneaded in this way is finally homogenized and extruded through the screw groove 3 formed by the flight controller formed at the tip of the measuring section.

In the above embodiments, the kneading section is provided at several locations, but the kneading section is not limited to this, and may be provided at several locations on the mixing screw. In that case, the effect of further strengthening the mixing effect can be obtained. [Effects of the Invention] According to the mixed screw of the present invention, the layer direction multi-flight flight and the reverse direction multi-flight flight are arranged opposite to the plane including the screw axis, and one Since the end of the flight was arranged so as to correspond to the screw groove formed by the other flight, the melt in the screw groove is repeatedly kneaded while exchanging positions with the melt in the previous and succeeding screw grooves. This has the effect of providing a cross-contact screw for single-screw extrusion that can extrude good extrudates with high efficiency without causing pressure generation, temperature rise, or decrease in extrusion rate, and the cross-contact effect is also improved. There is.

[Brief explanation of the drawing]

FIG. 1 is an external view of a cross-contact screw according to an embodiment of the present invention, and FIG. 1 is a partially enlarged detailed view of FIG. 1. /...kneading screw, co-flight, 3...screw groove, go-de...forward multi-thread flight, 10-/j...
・Reverse direction multi-thread flight, 16~-〇-forward direction screw groove, J/S-λ...reverse direction screw groove, A...supply section, B..melting section, 0..measuring section, D.・Kneading section. Patent applicant Nippon Urakosho Co., Ltd. Figure 2

Claims (1)

[Claims] In a single-screw extrusion kneading screw in which a supply section, a melting section, and a metering section are arranged from the root side, there is a forward multi-thread flight formed discontinuously in the forward direction that transports the mixed wire material forward, and a mixed wire material. A discontinuously formed reverse direction multi-flight flight is disposed in the opposite direction for transporting the above-mentioned bidirectional multi-flight flight to the rear, and is arranged oppositely on both sides of a plane including the axis of the kneading screw, and both ends of the bidirectional multi-flight flight are disposed on the other side. A kneading screw for single-screw extrusion, characterized in that at least one kneading section is provided in a portion of the melting section and the measuring section, the kneading section being arranged so as to correspond to the screw groove between the multi-thread flights.