JP2522204Y2 - High kneading vent extruder - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high kneading vent extruder applied to a single screw vent extruder of a plastic extruder.

[0002]

BACKGROUND OF THE INVENTION 10 In Figure 3 the screw 20 in the cylinder, the first stage S ₁ as shown in those members
When forming the second stage S _2. The α part is the first
Special kneading portion provided on the downstream portion of the stage S _1,
The outer peripheral surface of the screw 10 in the special kneading section α has a polygonal cross section perpendicular to the axial direction or a shape similar to a polygon.
Also, the inner peripheral surface of the cylinder 20 opposite to the axial direction has a polygonal or polygon-like cross-sectional shape perpendicular to the axial direction (FIGS. 4 and 5).

The β portion is a so-called ring valve mechanism,
The ring valve mechanism β moves the screw 10 appropriately in the axial direction, as is well known, to reduce the length L of the ring-shaped narrow gap between the outer peripheral surface of the screw 10 and the inner peripheral surface of the cylinder 20.
And the resistance to the resin passing through the gap is adjusted. The ring valve mechanism β
Is installed downstream of the special kneading section α as shown in FIGS.

Next, the operation of the extruder will be described. In FIG. 3, the resin fed into the cylinder 20 is:
As the screw 10 rotates, the screw reaches the special kneading portion α. In the kneading portion α, the cross-sectional shapes of the outer peripheral surface of the screw 10 and the inner peripheral surface of the cylinder 20 are formed in a polygonal shape or a similar shape. As shown in FIGS. 6A, 6B, and 6C, a gap (resin passage) formed between them.
A deforms as A ', A ". Therefore, the resin passing through the kneading portion α is forcibly deformed with the rotation of the screw 10, and the resin is subjected to a kneading action as if it were a mochi. Kneaded well.

In this case, the resin on the inner peripheral surface of the cylinder 20 moves toward the outer peripheral surface of the screw 10, and the resin on the outer peripheral surface of the screw 10 moves toward the inner peripheral surface of the cylinder 20. In this movement operation, the resin undergoes a division operation in which the resin is divided at the corners of the outer peripheral surface of the screw 10.
Further, as shown in FIG. 6 (c) , an inscribed circle at the inner peripheral surface corner of the cylinder 20 and an circumscribed circle a at the outer peripheral surface corner of the screw 10 are formed.
Is smaller than that of the conventional flight screw shown in FIG. 7 and has a wedge-like shape, so that the resin enters the wedge-shaped portion and receives a strong shearing action.

[0006]

SUMMARY OF THE INVENTION In a vent type extruder in which a vent hole for deaeration is provided immediately after a ring valve mechanism β downstream of a special kneading section α, a narrow gap of the present ring valve mechanism β is provided. Changing the length L of the part
Is utilized as a regulating function of the extrusion rate of the stage S _1. Depending also the resin used type, the change in the length L of the gap portion, the extrusion rate of the first stage S ₁ is changed abruptly, and may occur in extrusion variation, the conditions of optimal operation Since a long time is required for dispensing and a loss resin may be generated during the dispensing, it is necessary to consider a screw that does not cause a sudden change in extrusion performance by adjusting the length of the gap. The present invention is intended to solve the above-mentioned conventional problems.

[0007]

SUMMARY OF THE INVENTION For this reason, the present invention has a kneading portion having a polygonal or similar shape in a cross section perpendicular to the axis, and a vent hole in a portion of a front portion of a degassing portion of a cylinder and a screw. There is a ring valve mechanism part immediately upstream of the vent extruder provided with the kneading part further upstream thereof, while forming at least one dam flight having a lead between the polygonal tops of the kneading part screw, A torpedo portion with a polygonal portion removed is provided downstream of the dam flight, which is used as a means for solving the problem.

[0008]

[Action] By providing a torpedo with a polygonal shape removed from the polygonal screw downstream of the dam with the same or a smaller number of stages as the dam, the feed capability at the polygonal screw is reduced, and the ring valve mechanism is reduced. In this case, the range of adjustment of the length of the gap can be increased, and the operation can be facilitated for a wide range of resins.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a first embodiment of the present invention; FIG. First, FIG.
In the high kneading vent extruder (a), a solid resin is supplied from a raw material supply port 1, the resin is moved toward a die at an extruder outlet (not shown) by a screw 2, and plasticized and melted by shear stress. Reference numeral 3 denotes a polygonal screw having a high kneading function, and 4 denotes a polygonal cylinder. These are the same as the polygonal screw and the polygonal cylinder in the polymer substance extrusion apparatus disclosed in Japanese Patent Publication No. 54-19908. Things.

The polygonal screw 3 is disclosed in Japanese Patent Publication No. 58-2
No. 9732 has a dam 5 having a high kneading function as in the high kneading extruder, and a torpedo 7 from which the peak 6 of the polygonal screw 3 is removed is provided downstream of the dam 5. . The torpedo 7 is formed with the same number as the number of steps of the dam 5 or a smaller number of steps. Further, the extruder of the present invention shown in the embodiment of FIG. 1 has a ring valve mechanism 8 at the outlet of the polygonal screw 3 as disclosed in Japanese Patent Publication No. 58-29734 and a further downstream. A vent hole 9 for deaeration is provided on the side.

Next, the operation will be described. The dashed line in FIG. 1 (b) shows the change in the pressure of the molten resin in the cylinder in FIG. 3, and the operation will be described by comparing the conventional example with the present invention with reference to FIG. The length L of the gap portion of the ring valve mechanism 8 is a negative value, that is, the pressure of the molten resin in the cylinder in the state where the throttle is not applied is a = 0 → b → c → d =
It changes to 0. On the other hand, the lengths of the gaps are L ₁ , L ₂
, The molten resin pressure becomes a = 0 → b ′ →
As c ′ → d = 0, a = 0 → b ″ → c ″ → d = 0, the resin pressure at the end of the section A and the end of the special kneading section α increases. In this case L = the L ₂ becomes close, move melting start point of the section A is a 1 → 3, causes a significant reduction in the extrusion rate solid transportation capacity is rapidly reduced. That is, the adjustment range of L value is in the narrow range and L~L _2.

In order to widen this range, it is necessary to reduce the resin pressure at the outlet of the kneading section in the open state where the length of the gap is minus. That is, in the screw shown in FIG. 1, by providing the torpedo section 7, the feeding ability of the molten resin in the special kneading section α is reduced, and by changing the kneading section outlet resin pressure from c to x, the adjustment range is adjusted. The pressure c → c ″ can be expanded to x → c ″. In addition, the kneading section outlet resin pressure b or less, that is, eliminating the feeding ability of the molten resin in the kneading section will give a large resistance,
This leads to a decrease in the throughput.

[0013]

As described in detail above, the present invention provides a polygon screw by providing a torpedo having a polygon shape removed from the polygon screw downstream of the dam with the same or less number of steps as the dam. In this case, it is possible to reduce the feedability of the ring portion, to increase the adjustment range of the length of the gap in the ring valve mechanism, and to facilitate the operation for a wide range of resin.

[Brief description of the drawings]

FIG. 1 is a side sectional view of an extruder according to an embodiment of the present invention and an explanatory diagram showing a change in resin pressure in a cylinder in comparison with a conventional example.

FIG. 2 is an enlarged sectional view taken along line Y-Y of FIG. 1;

FIG. 3 is a side sectional view of a conventional extruder.

FIG. 4 is an enlarged side sectional view of a main part in FIG. 3;

FIG. 5 is a sectional view taken along line XX of FIG. 4;

FIG. 6 is an explanatory view showing a rotating state of the screw in FIG. 5;

FIG. 7 is a front sectional view of a conventional flight screw.

FIG. 8 Of a dam flight with leads between polygonal tops
FIG.

[Explanation of symbols]

 2 screw 3 polygonal screw 4 polygonal cylinder 5 kneading dam flight 6 polygonal peak 7 torpedo 8 ring valve mechanism 9 vent hole

Claims (1)

(57) [Scope of request for utility model registration] 1. A kneading portion having a polygonal or similar cross-sectional shape perpendicular to the axis is provided at a portion of a front portion of a degassing portion of a cylinder and a screw, and a ring valve mechanism is provided immediately upstream of a vent hole . , The kneading further upstream
In a vent extruder provided with a portion , at least one dam flight having a lead is formed between polygonal tops of the kneading portion screw and a torpedo portion having a polygon portion removed is provided downstream of the dam flight. A high-kneading vent extruder characterized in that: