JP4312363B2 - Kneading disc - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a kneading disk suitable for kneading a plastic compound.
[0002]
[Prior art and problems]
Conventionally, a plastic compound is manufactured using, for example, a screw type extruder shown in FIG. In this extruder, a screw 41 rotatably arranged in a cylinder barrel 40 is rotated by a rotary drive device 42 such as a motor and a speed reducer, and a plastic compound is pushed out from a die 43 at the tip of the cylinder barrel 40. is there. The screw 41 has a flight screw 33 having a spiral groove, a first kneading unit 31, a flight screw 34, a second kneading unit 35, and a flight screw 37 in order from the base end.
[0003]
When producing a compound of a base polymer and a needle-like filler such as a whisker by this extruder, first, the base polymer introduced from the hopper 30 is transferred by the flight screw 33 and plasticized in the first kneading unit 31. . Thereafter, needle fillers are introduced into the plasticized base polymer by an input device 32 for supplying raw materials from the middle of a side feeder or the like provided corresponding to the flight screw 34.
[0004]
This is because when the needle-shaped filler is plasticized and kneaded together with the base polymer in the first kneading section 31 (base polymer plasticizing section), very fine needle-shaped filler breaks due to shear stress and pressure during plasticization, This is to avoid a problem that a final product having a desired quality cannot be obtained. That is, if a needle-like filler is added after the base polymer is plasticized and kneaded, it is not necessary to generate a large shear stress or pressure as in the plasticization of the base polymer, so that a so-called mild kneading is possible.
[0005]
Thus, when the base polymer charged from the hopper 30 is mainly plasticized in the first kneading section 31 and then transported toward the second kneading section 35 by the flight screw 34, the first kneading section 31 and the second kneading section 31 are used. The needle-like filler is introduced from the place of the flight screw 34 between the part 35 and the needle-like filler is kneaded in the second kneading part 35 together with the base polymer plasticized in the first kneading part 31. . In general, kneading disks 36 are used for the first kneading unit 31 and the second kneading unit 35 of the screw 41, respectively.
[0006]
However, the conventional kneading disk 36 has an annular edge 36a on the entire outer periphery as shown in FIG.
[0007]
For this reason, the needle filler kneaded in the second kneading part 35 is excessively compressed by the edge part 36 a of the kneading disk 36 and breaks. When this was observed closely, the breakage of the needle filler was mainly caused by the side surface of the end of the kneading disc 36 in the major axis direction, that is, the front end 36b in the rotational direction A of the kneading disc 36 (the hatched line in FIG. 5). It was found that this occurs in the part shown). This is presumed to be because the edge portion 36a of the tip portion 36b having a high peripheral speed is greatly involved in damage to the needle-like filler.
[0008]
Therefore, the present invention removes at least the edge portion of the front end portion of the outer periphery of the kneading disk used in the second kneading portion and the like, and forms a smooth curved surface so that the needle-like filler at the time of kneading, etc. It is intended to prevent excessive compression of the reinforcing material, prevent damage, and prevent functional deterioration of the reinforcing material such as needle fillers.
[0009]
[Means for Solving the Problems]
The present invention has been made in view of such a conventional technical problem, and the configuration thereof is as follows.
The invention of claim 1 is the kneading disk provided in the kneading part of the screw, wherein the kneading disk has an elliptical outer shape in front view from the central axis direction of the screw, and is orthogonal to the central axis direction. the side view of the minor axis of the ellipse is kneading disc, wherein a pair of convex curved surface in the major axis direction end portion is made form.
According to a second aspect of the present invention, there is provided a pair of smooth outlines (15, 16) having parallel lines on both sides between the respective convex curved surfaces and having no corners and having no ridge lines in the side view. There is a kneading disc of claim 1, wherein that you are formed.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 3 show an embodiment of a kneading disk according to the present invention.
The front view of the kneading disk 1 viewed from the central axis direction of the screw 41 has an elliptical outer shape as shown in FIG. 1, and a through hole 12 having a protrusion 11 is formed at the center. The kneading disk 1 is attached to the recess 41a of the screw 41 so that the protrusion 11 is engaged with the protrusion 11 so that the kneading disk 1 cannot be rotated relative to the kneading disk 1 and constitutes the second kneading portion 35 shown in FIG. To do. The protrusion 11 is formed in a serrated shape, or is formed by giving the through-hole 12 an irregular cross-sectional shape other than a circle such as a polygonal cross-section.
[0011]
Further, in the side view seen short radius direction towards E or et of ellipse perpendicular to the central axis line direction, the lower end portions on along the major axis direction F of the ellipse as shown in FIG. 2 (major axis direction end portion), A pair of convex curved surfaces 13 and 14 is formed, and both convex curved surfaces 13 and 14 are smoothly connected with no corners so as to be represented by parallel contour lines 15 and 16, and there is no ridge line. . Here, the convex curved surfaces 13 and 14 are generally formed in a convex arc shape or a convex elliptical shape. Further, it is only necessary to connect the both ends in the major axis direction forming the convex curved surfaces 13 and 14 with smooth outlines having no ridgeline, and the outlines 15 and 16 are expressed not only with various straight lines but also with curves. Including things. Further, when the kneading disk 1 has a triangular shape and has three front end portions in the rotational direction A, the gap between the convex curved surfaces 13 and 14 at the front end portions in the adjacent rotational direction A is smooth. What is necessary is just to be connected by the outer outlines 15 and 16.
[0012]
As described above, since the outer shape of the kneading disk 1 is elliptical when viewed from the center axis direction of the screw 41 , the convex curved surfaces 13 and 14 are convex curved when viewed from the front. . However, since the rear portions connected to the convex curved surfaces 13 and 14 of the kneading disk 1 are difficult to apply a compressive force during kneading, the convex curved surfaces 13 and 14 are formed only at both ends of the kneading disc 1 in the major axis direction. This is sufficiently effective, and the shape of the tip of the rear surface side in the rotation direction A of the kneading disk 1 may be arbitrary.
[0013]
That is, the kneading disc 1 is only required to cut the corners of the upper and lower ends (both ends in the major axis direction) in a front view to give an oval smooth outer shape as compared with the conventional kneading disc. First, as shown by a broken line 50 in FIG. 3, the corners of the upper and lower ends (both ends in the major axis direction) are cut away in a side view to give a smooth outer shape having an oval shape as a whole. Accordingly, in the kneading disk 1 shown in FIGS. 1 and 2, the radial cross section of the outer peripheral portion forms a convex arc shape or a convex elliptic shape on the entire circumference.
[0014]
If such a kneading disk 1 is provided in the second kneading part 35, since there is no edge part on the outer peripheral part, an excessive compressive force is applied to the needle-like filler by the kneading disk 1 rotating in one direction A. The action is suppressed, and the needle-like filler is well prevented from being broken. In particular, the melted base polymer and needle filler located on the front side in the rotational direction A of the kneading disk 1 reach the tip while being extruded in the outer diameter direction in FIG. Without excessive compression, it branches in the directions of arrows B and C and undergoes kneading. Moreover, even when viewed from the front in the direction of the central axis of the screw 41, the front end on the front side in the rotational direction A that forms the convex curved surfaces 13 and 14 has a convex curved surface. The filler undergoes kneading while smoothly branching in the directions of arrows B and C.
[0015]
As a result, the quality of a product obtained by compounding a base polymer and a needle-like filler such as a whisker can be improved. According to this kneading disk 1, it is needless to say that damage to the reinforcing material is suppressed even when other reinforcing material is kneaded with the base polymer, not limited to the needle-like filler.
[0016]
One kneading disk 1 may be provided in a kneading section such as an extruder or an injection machine, but it is also possible to provide two or more kneading disks 1 whose phases are shifted in the circumferential direction. is there.
[0017]
【Example】
Actually, one kneading disk 1 is used in the second kneading section 35 of the twin-screw extruder shown in FIG. 4, and POM (acetal resin) pellets are used as the base polymer, and potassium titanate whiskers are used as the needle filler. These were kneaded at a ratio of 7: 3.
[0018]
The POM pellets were charged from the hopper 30 and plasticized by the first kneading unit 31, and the potassium titanate whiskers were charged halfway from the charging device 32 at a position after the first kneading unit 31. When the compound in the molten state passing through the second kneading part 35 and extruded from the tip part (die 43) of the twin-screw extruder was observed, it was compared with the case where the second kneading part was constituted by a conventional kneading disk. Thus, it was confirmed that the breakage of the potassium titanate whisker was remarkably reduced. This is presumed to be a result of the excessive compressive force of the kneading disk 1 not acting on the potassium titanate whisker when kneaded by the kneading disk 1 in the second kneading section 35.
[0019]
【The invention's effect】
As understood from the above description, according to the kneading disk according to the present invention, in an extruder, an injection molding machine or the like provided with the kneading disk in the kneading part, damage to the reinforcing material such as a needle filler Therefore, when it is compounded with the base polymer, the function as the core material is maintained well, and an effect is obtained that a compound having a desired strength can be obtained. In addition, the compound can be efficiently manufactured by increasing the number of rotations of the screw while suppressing damage to the reinforcing material.
[Brief description of the drawings]
FIG. 1 is a front view showing a kneading disc according to an embodiment of the present invention.
It is an enlarged side view of FIG. 1. FIG.
FIG. 3 is an action expanded Description of FIG. 1.
[4] The conventional and push out machine according to kneading disk according to the present invention is a schematic diagram showing in cross-section.
FIG. 5 is a perspective view showing a conventional kneading disk.
[Explanation of symbols]
1 Kneading disc 13, 14 Convex curved surface 15, 16 Outline 41 Screw A Rotation direction
E minor axis direction
F major axis direction

Claims (2)

Oite the kneading disk comprising a kneading section of the screw (41), the kneading disc (1), the outer shape in a front view from the central axis line direction of the screw (41) forms the elliptical shape, the central axis kneading disc, wherein said pair of convex surface in the major axis direction (F) both end portions in side view from the minor axis of the ellipse (E) perpendicular to the direction (13, 14) are made form. Wherein the two over loading disk (1), wherein in a side view, wherein the convex curved surface (13, 14) without ridgeline eliminating the corners with consisting parallel lines on each side between the pair of smooth outline (15 , kneading disc of claim 1, wherein that you 16) is formed.

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