JPH0825456A - Extrusion screw of twin-screw extruder - Google Patents

Abstract

PURPOSE:To provide an extrusion screw preventing the short pass phenomenon between a different kind of resin raw materials to enhance the mixing and kneading effect of the raw materials. CONSTITUTION:In the extrusion screw 10 of a twin-screw extruder equipped with a pair of parallelly extending screws 14, 16 rotating within a barrel 12 in a mutually meshed state and constituted so as to knead and melt a resin raw material M on the upstream side of the barrel to allow the kneaded raw material to flow toward the downstream part thereof to extrude the same, a mixing and stirring device constituted of a kneading and mixing part 22 consisting of engaged rotary blade pairs 18, 20 and a fluidizing and stirring part 28 consisting of large and small slide contact rotary discs 24, 26 is provided to the intermediate part L in the longitudinal direction of the screw 10 in coaxial relation to the screw.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extrusion screw of a twin-screw extruder, in particular, a co-rotating twin-screw extruder, and improves the mixing and kneading effect between different resin raw materials processed by this extrusion screw. The extruded screw.

[0002]

2. Description of the Related Art Generally, the extrusion screw of a twin-screw extruder is
The barrel consists of a pair of screws extending in parallel so that they rotate in mesh with each other, and the resin raw material supplied from the inlet on the upstream side is pressure-fed through the groove portion of the screw to knead and melt to the downstream side. It is configured to flow and extrude toward the extrusion port.

Therefore, according to this type of extrusion screw,
Products extruded from resin stock can be manufactured automatically and continuously.

[0004]

However, the extrusion screw of the conventional twin-screw extruder still has the following drawbacks.

That is, as described above, the conventional extrusion screw is constructed so that the resin raw material is kneaded and melted by being fed under pressure through the screw groove portion. However, in this type of twin-screw extruder, In particular, in the extrusion screw of the twin-screw extruder of the same direction rotation, since the screw groove portion is continuous, a so-called short pass phenomenon of the treated resin raw material occurred. For example, in processing between different resin raw materials having a large difference in melting temperature, the resin raw material having a lower melting temperature is first melted, and in this case, this molten resin acts as a kind of lubricant. Therefore, the resin raw material having a higher melting temperature which still maintains the solid state is prevented from both the kneading action by mechanical shearing and the uniform dispersion (mixing) with the molten resin, resulting in a homogeneous product. Quality could not be achieved.

Therefore, an object of the present invention is to improve the mixing and kneading effect of the raw materials by preventing the short pass phenomenon between the raw materials, especially in the treatment between the different resin raw materials. To provide an extruder screw for a machine.

[0007]

In order to achieve the above object, an extrusion screw of a twin-screw extruder according to the present invention comprises a pair of parallel extending screws in a barrel for meshing rotation. In an extrusion screw of a twin-screw extruder configured to knead and melt the upstream resin raw material, flow it to the downstream side, and extrude it, in the longitudinal intermediate portion of the screw, coaxial with the screw It is characterized in that a mixing / stirring device comprising a kneading / mixing part composed of a pair and a fluidized stirring part composed of a large / small rotating disk in sliding contact is provided.

In this case, the mixing and stirring apparatus can be constructed by alternately combining a plurality of the kneading and mixing sections and the fluidized stirring section.

Further, the mixing and stirring apparatus can be constructed such that the phases of the rotary blade pairs of the kneading and mixing section are sequentially shifted, and the arrangement of the large and small rotating disks of the fluidized stirring section is exchanged alternately.

Further, in the mixing and stirring apparatus, the pair of rotary blades in the kneading / mixing section can be composed of two and / or more multi-profiles.

[0011]

In the present invention, the short-pass phenomenon between different kinds of resin raw materials, which is generated by being guided by the screw groove portion, can be effectively prevented by the mixing and stirring device. That is, the flow of different resin raw materials introduced from the screw groove portion into the mixing and stirring apparatus is first sheared and mutually melted in the kneading and mixing section of the mixing and stirring apparatus, and then sequentially melted in the flow stirring section. Change and stir to disperse each other. Then, each operation of the mixing stirring and the fluidized stirring is repeatedly applied as necessary. Therefore, according to the present invention, since the short-pass phenomenon between the raw materials is prevented in this way, it is clear that the kneading and mixing effect of the raw materials can be greatly improved.

[0012]

EXAMPLES Examples of the extrusion screw of the twin-screw extruder according to the present invention will be described below in detail with reference to the accompanying drawings.

1 and 2, first, the basic structure of the extrusion screw of the twin-screw extruder (rotating in the same direction) of the present invention is the same as the conventional one. That is, the extrusion screw 10 basically includes a pair of screws 14 and 16 extending in parallel in the barrel 12 so as to mesh with each other and rotate. Then, the resin material M (schematically indicated by a flow or a flow line) supplied from an inlet (not shown) on the upstream side is fed into the grooves 14a of the screws 14 and 16,
It is configured to be kneaded and melted by being pressure-fed through 16a to be flowed toward an extrusion port (not shown) on the downstream side and extruded.

According to the present invention, however, in the above-mentioned structure, the extrusion screw 10 has an intermediate portion L in the longitudinal direction thereof coaxial with the screw shafts 14b and 16b.
A kneading and mixing section 22 composed of a pair of engaging rotary blades 18, 20;
Sliding contact large / small rotating disk 24, 26
A mixing and stirring device 30 composed of In this case, the mixing / stirring device 30 is usually, as shown in the drawing,
The kneading / mixing section 22 and the fluidized stirring section 28 are configured so as to be alternately combined. Therefore, the pair of rotary blades 18 and 20 of the kneading / mixing unit 22 are, in one embodiment in which the phases thereof are sequentially shifted, each formed of an elliptical two-row profile having a 90 ° phase shift [(a) and (a) in FIG. 2]. (C)
Reference] together with the large and small rotating discs 24 of the flow stirring unit 28,
26 is configured so that its arrangement is alternately exchanged [see (b) and (D) of FIG. 2].

According to the present invention, however, the flow of the different resin raw material M guided by the screw groove portions 14a, 16a and introduced into the mixing / stirring device 30 is as follows.
2, especially in the sliding contact portion between the pair of rotary vanes 18 and the large rotating disk 24 of the adjacent flow stirring unit 28 (see the hatched portion in FIG. 3) or the wedge-shaped portion formed between the barrel wall surfaces, the shearing blades are mutually sheared. It is crushed and melted sequentially. And
The flow of the raw material M thus melted is the flow stirring unit 28.
In particular, the flow direction is obstructed by the large rotation disk 24, and the flow direction is rapidly changed to the opposite side (small rotation disk 26) and agitated, so that the particles are dispersed. The flow of the raw material M dispersed in this way flows to the mixing and stirring device 30 on the further downstream side, if necessary, and the above action is repeatedly given. In this case, the rotary blade pair 1 in each of the kneading and mixing section 22 and the flow stirring section 28 of the upstream and downstream mixing and stirring apparatus 30.
As described above, the 8 and 20 and the large and small rotating disks 24 and 26 are out of phase with each other or the arrangements thereof are exchanged. Therefore, it is clear that the effect obtained by the above operation can be further increased.

As described above, according to the present invention, the short-pass phenomenon between different kinds of resin raw materials, which is about to be guided by the screw groove portion, is effectively caused by the mixing and stirring device provided at the intermediate portion in the longitudinal direction of the screw. Can be stopped. Therefore, it is clear that the kneading and mixing effect of different resin raw materials can be greatly improved.

4 and 5 show different embodiments of the extrusion screw according to the present invention. These examples
Kneading and mixing section (rotary blade) 40 in the mixing and stirring device
The shapes of a, 40b, 42a, and 42b are configured to have three-row and four-row profiles, respectively, from the two-row profile in the previous embodiment. Note that reference numerals 44 and 46 in the figure respectively indicate a large rotating disk and a small rotating disk. In addition, also in these embodiments, the same operation and effect as in the case of the above-mentioned embodiments are exhibited, and therefore detailed description will be omitted.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and many design changes can be made without departing from the spirit of the present invention. Further, the present invention is not limited to the same-direction rotating type or the meshing type described above, and is similarly applicable to other extruders such as a different-direction rotating type, a non-meshing type or an integral type, and an assembly type extruder. It is possible to apply.

[0019]

As described above, the extrusion screw of the twin-screw extruder according to the present invention is provided with a pair of parallel extending screws in the barrel, which are engaged with each other and rotate in parallel with each other. In an extrusion screw of a twin-screw extruder configured to be kneaded, melted, flowed to a downstream side and extruded, a kneading / mixing unit including a pair of engaging rotary blades is provided at an intermediate portion in a longitudinal direction of the screw, coaxially with the screw. By providing a mixing and stirring device composed of a fluid stirring unit composed of a sliding contact large / small rotating disc, the short-pass phenomenon between different resin raw materials which is generated by being guided by the screw groove portion is prevented by the mixing stirring device. It can be reliably blocked.

Therefore, according to the present invention, even with different kinds of resin raw materials, the kneading and mixing between these raw materials are sufficiently achieved, so that a uniform product quality can be secured.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts showing an embodiment of an extrusion screw of a twin-screw extruder according to the present invention.

2 is a cross-sectional view of the mixing and stirring device shown in FIG.
(A) is a sectional view taken along the line A, (b) is a sectional view taken along the line B, and (c) is a sectional view.
A line sectional view, (d) is a D line sectional view.

FIG. 3 is a front view showing a sliding contact crushed portion of the extrusion screw shown in FIG.

4A and 4B show another embodiment of the extrusion screw of the twin-screw extruder according to the present invention, in which FIG. 4A is a sectional view in the direction perpendicular to the axis, and FIG. 4B is a sectional view in the axial direction.

5A and 5B show still another embodiment of the extrusion screw of the twin-screw extruder according to the present invention, wherein FIG. 5A is a sectional view in the direction perpendicular to the axis, and FIG. 5B is a sectional view in the axial direction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Extrusion screw 12 Barrel 14, 16 Screw 14a, 16a Screw groove part 14b, 16b Screw shaft 18, 20 Rotating elliptical blade pair 22 Kneading mixing part 24 Large rotating disk 26 Small rotating disk 28 Flow stirring part 30 Mixing stirring device 40a, 40b Kneading mixing Part (three-way profile) 42a, 42b Kneading and mixing part (four-way profile) 44 Large rotating disk 46 Small rotating disk

Claims (4)

[Claims] 1. A twin-screw extruder having a pair of screws extending parallel to each other and rotating in mesh with each other in a barrel, kneading and melting a resin material on an upstream side, flowing the resin material to a downstream side, and extruding the resin material. In the extruder screw of the machine, a mixing and agitating unit consisting of a kneading and mixing unit consisting of a pair of engaging rotary blades and a fluid agitating unit consisting of a large and small rotating disk in sliding contact is provided in the middle of the screw in the longitudinal direction. An extrusion screw for a twin-screw extruder, which is provided with a device. 2. The mixing / stirring device is configured by alternately combining a plurality of kneading / mixing sections and fluidized stirring sections.
Extrusion screw of the described twin-screw extruder. 3. The mixing / stirring device is configured such that the phases of the rotary blade pairs of the kneading / mixing part are sequentially shifted, and the flow / stirring part is large.
The extrusion screw for a twin-screw extruder according to claim 1, wherein the arrangement of the small rotating disks is alternately changed. 4. The twin-screw extruder according to any one of claims 1 to 3, wherein the mixing / stirring device has a pair of rotary blades in the kneading / mixing section, which comprises two and / or more multi-profiles. Extrusion screw.