JPH0627381Y2 - Extruder - Google Patents

Description

[Detailed Description of the Invention] (a) Industrial Application Field The invention is based on synthetic resins such as urethane, vinyl chloride, polyester resin, polyethylene resin, and the like, masterbatch, calcium carbonate, talc, glass fiber, carbon fiber. The present invention relates to an extruder for kneading and extruding mixed raw materials such as.

(B) Prior Art Conventionally, as the extruder of the above-mentioned example, for example, a twin-screw type extruder in which two rotary screws for kneading are rotatably supported inside a heating cylinder, and a rotary screw for kneading There is an extruder in which a large number of kneading recesses are formed on the outer peripheral surface of the kneading part formed to have the maximum outer diameter.

(C) Problems to be solved by the invention However, in order to enhance the kneading action of the above-mentioned kneading rotary screw, when a large number of complex kneading recesses were engraved on the outer peripheral surface of the kneading part, this occurred during engraving. Since metal fatigue easily occurs in the kneading recess due to the residual stress and it becomes partially brittle, there is a structural limit to enhancing the kneading action of the raw material only by the shape of the kneading recess engraved in the kneading rotary screw.

Further, using the above-mentioned single-screw type or twin-screw type extruder,
For example, when a mixed raw material such as a masterbatch, calcium carbonate, or talc is kneaded, since the mixed raw material is forcibly kneaded only by the kneading recesses formed in the kneading portion of the kneading rotary screw, a higher pressure than necessary is mixed. The problem is that the quality of the extruded kneading raw material deteriorates because it is given to the raw materials, and depending on the mixed raw materials, the characteristics may be impaired or the molecular structure of the mixed raw materials may be destroyed, and the molecular weight thereof may decrease. I also have.

This invention is to knead uniformly and sufficiently while keeping the molecular weight of the mixed raw material constant without impairing the characteristics of the mixed raw material.
An object of the present invention is to provide a kneading structure of a rotary screw for kneading, which can be kneaded in an optimum state according to the type and characteristics of a mixed raw material to be kneaded.

(D) Means for Solving the Problems The present invention is an extruder in which a rotary kneading screw is rotatably inserted into a heating cylinder having an input port at one end and an extrusion port at the other end. And forming a kneading recess in the kneading portion of the kneading rotary screw in which the flow cross-sectional area of the raw material gradually decreases from the raw material transfer start end to the raw material transfer end, and the inner peripheral surface of the heating cylinder corresponding to substantially the entire width of the kneading portion. In addition, the extruder is characterized in that a spiral groove is formed in which the screwing direction is opposite to the screwing direction of the kneading rotary screw.

(E) Action This invention is to rotate the kneading rotary screw in the raw material transfer direction to transfer the mixed raw material charged into the heating cylinder to the extrusion port side, and at the same time, cut the raw material flow in the kneading part of the kneading rotary screw. Since the area gradually decreases, high pressure can be applied to the raw materials in sequence, and the mixed raw material flowing out from the kneading recess formed in the kneading part of the kneading rotary screw is formed on the inner peripheral surface of the heating cylinder. The mixed raw material flowing out of the spiral groove of the heating cylinder is made to flow into the kneading concave portion of the kneading rotary screw, and the kneading concave portion of the kneading rotary screw is heated. The splitting and merging of the mixed raw material is continuously repeated between the spiral raw material and the spiral groove of the cylinder, and the mixed raw material flowing along the kneading concave portion of the rotary screw for kneading and the spiral raw material of the heating cylinder. Then, the flow direction of the flowing mixed raw material is crossed to generate a turbulent flow phenomenon between the mixed raw materials at the intersecting portions, and the kneading is performed in an optimum and sufficient kneading state corresponding to the mixed raw material to be kneaded.

(F) Effect of the invention According to this invention, since the kneading concave portion of the kneading rotary screw formed in the spiral direction and the spiral concave groove of the heating cylinder formed in the reverse spiral direction are kneaded in a crossing state, for example,
When a masterbatch, talc, or the like is mixed and kneaded with a synthetic resin such as polyester resin or polyethylene resin, if a higher pressure than necessary is applied to the mixed raw material flowing through the kneading concave portion of the kneading rotary screw, the mixture is mixed. Since the raw materials flow out from the kneading concave portion and flow backward along the spiral concave groove of the heating cylinder, the molecular structure of the mixed raw material is not broken, and the kneading can be sufficiently performed while keeping the molecular weight constant.

Moreover, the characteristics of the mixed raw material are remarkably kept better than those of the conventional single-screw or twin-screw extruder, and along the kneading recesses of the kneading rotary screw and the spiral recesses of the heating cylinder. Since it flows in two directions, the fluidity is not reduced or impaired during kneading, and due to the synergistic kneading action due to the mutual crossing, it is in an appropriate and sufficient state according to the type and characteristics of the mixed raw materials to be kneaded. It can be kneaded.

(G) Embodiment An embodiment of the present invention will be described in detail below with reference to the drawings.

The drawing shows an extruder used for kneading a mixed raw material in which a masterbatch, talc, etc. are mixed with a polyester resin, polyethylene resin, etc., and in FIG.
Is a kneading rotation inside a heating cylinder 4 having an opening 2 for introducing the mixed raw material on the upper surface of the base end (raw material transfer start side) and an extruding opening 3 on the front end (raw material transfer end side). The screw 5 is rotatably supported.

In the heating cylinder 4 described above, a first vent hole 6 for deaeration is opened on the upper surface on the base end side, a second vent hole 7 is opened on the upper surface on the tip end side, and a plurality of vent holes are formed on the outer peripheral surface of the heating cylinder 4. Each of the band heaters 8 are wound around the axial direction at a predetermined interval, and a hopper 9 for charging a raw material is connected to the charging port 2 at the base end.

In the heating cylinder 4, as shown in FIGS. 1 and 2, the raw material set between the first vent hole 6 and the second vent hole 7 and in the vicinity of the second vent hole 7. Kneading section 1
0 over the entire width of the inner peripheral surface 10a of the kneading rotary screw 5 described later so that the spiral direction is opposite to the spiral direction (screw direction). Is formed.

As shown in FIG. 4, the kneading rotary screw 5 has the heating cylinder 4 on the outer peripheral surface of the kneading section 12 set at a position corresponding to the raw material kneading section 10 of the heating cylinder 4.
A large number of independent kneading concave portions 13 are continuously formed along the spiral direction intersecting the spiral concave grooves 11.

Each of the above-mentioned kneading recesses 13 ... Spirals on the outer peripheral surface of the kneading part 12 formed to have the maximum outer diameter of the kneading rotary screw 5 as it goes from the raw material transfer start end side of the kneading part 12 toward the raw material transfer end side. The trenches are formed so that the groove depth becomes smaller along the same.

As shown in FIG. 5, the state of formation is such that the kneading section 12 is oriented toward the center of the shaft about the axially eccentric positions of the center of the kneading rotary screw 5 vertically and horizontally.
Is formed on the outer peripheral surface so that the cross-sectional shape in the spiral direction is a two-sided elliptical shape.

That is, each of the kneading recesses 13 ... Is formed so that the groove depth becomes the deepest at the central portion in the spiral direction, and the groove depth becomes gradually shallower as it is separated from the central portion in the spiral direction in the spiral direction. Then, the kneading portion 12 is formed into a smooth groove shape along the spiral direction, and as shown in FIG. 5 (a), the kneading portion 12 has a cross section taken along the line AA in FIG.
As shown in (b) of the figure, the kneading section 12 is changed to BB of FIG.
Each kneading recess 13 arranged between the cross section taken along the arrow
The central groove depth of ... is formed such that the groove depth is gradually reduced by a predetermined depth 1 in the screwing direction, and the flow cross-sectional area of the raw material is gradually reduced from the raw material transfer start end to the raw material transfer end.
The high pressure is sequentially applied to the material to be transferred.

Each of the above-mentioned kneading recesses 13 ... As a permissible part for the flow of the mixed raw material in the spiral direction (screw advance direction), each first flow passage 14 ... Is formed in the vicinity of each kneading recess 13 ... Respectively, and each of these first flow passages 14 ...
The groove depth of the kneading part 12 is as shown in FIG.
In the portion of FIG. 4 taken along the line BB in FIG. 4, the groove depth is set to allow the flow of the mixed raw material in an amount substantially equal to that of the central portion of the kneading recess 13, and the groove depth is shown in FIG. As described above, the groove depth is set to allow the flow of a small amount of the mixed raw material in the portion taken along the line AA in FIG. 4, and the groove depth is gradually decreased along the spiral direction (screw direction). Is formed.

Further, each of the above-mentioned kneading recesses 13 ... Is a second flow passage in the vicinity of each of the kneading recesses 13 ... Adjacent in the spiral width direction as a flow allowing part of the mixed raw material in the spiral width direction (front-back direction). 15 are formed and are connected to each other.

The kneading rotary screw 5 has its base end connected to a drive mechanism (not shown) such as a drive motor, and is rotationally driven in the raw material transfer direction (arrow direction).

The illustrated embodiment is constructed as described above, and the operation will be described below.

As shown in FIG. 3, the mixed raw material charged into the hopper 9 of the extruder 1 is transferred by the kneading rotary screw 5 rotating in the raw material transfer direction (arrow direction), and the heating cylinder 4 is heated.
While being supplied in a fixed amount, it is sequentially transferred to the extrusion port 3 side.

During the transfer, the mixed raw material is heated and melted by each band heater 8 and degassed through the first vent hole 6, and then the mixed raw material is mixed with each kneading recess 13 formed in the kneading portion 12 of the kneading rotary screw 5. , And the spiral grooves 11 formed in the raw material kneading section 10 of the heating cylinder 4 are moved in and out while being kneaded.

That is, the mixed raw material is the kneading section 1 of the kneading rotary screw 5.
2 flows into the kneading recesses 13 with deep groove depths engraved on the front side (front side) of FIG.
Through the ridges, the groove depths adjacent to each other in the spiral direction (screw advance direction) are divided into the respective kneading recesses 13 having a shallow depth, and a part of the groove depths adjacent to each other in the spiral width direction via the respective second flow passages 15. Is divided into the respective kneading recesses 13 having a shallow depth, and a part of the kneading recesses 13 passing over the peripheral wall portion of each kneading recess 13 ... Adjacent in the spiral direction and the screw axis direction is provided in the kneading recesses 13 having a shallow groove depth. The mixed raw materials are split and merged with the mixed raw materials split from the other kneading recesses 13 ...

In this way, the mixed raw materials sequentially flow from the kneading recesses 13 having a deep groove depth into the kneading recesses 13 having a shallow groove depth, thereby allowing passage of the mixed raw material (passage cross-sectional area of the raw material). ) Is gradually narrowed, and a high pressure is sequentially applied to the flowing mixed raw material, and at the same time, the flow rate of the mixed raw material is gradually increased while the flow rate of the mixed raw material is gradually increased. It is limited by ... and a high biting force (kneading action) is sequentially applied.

The mixed raw material during the transfer is positively kneaded by the pressure change generated when the mixed raw material is flowed into each kneading concave portion 13 ... and the turbulent flow phenomenon generated when the mixed raw material is split and merged into each kneading concave portion 13.

On the other hand, a part of the mixed raw material flowing out from each kneading concave portion 13 of the kneading rotary screw 5 is caused to flow into each spiral concave groove 11 formed in the raw material kneading portion 10 of the heating cylinder 4 and the heating cylinder 4 A part of the mixed raw material flowing out from each spiral groove 11 is made to flow into each kneading concave portion 13 of the kneading rotary screw 5 again, and each kneading concave portion 1 of the kneading rotary screw 5 is made.
.. and the spiral grooves 11 of the heating cylinder 4 are continuously divided and joined together.

At the same time, each kneading concave portion 13 of the kneading rotary screw 5 is
The flow directions of the mixed raw material flowing along the ... and the mixed raw material flowing backward along each spiral groove 11 of the heating cylinder 4 are alternately crossed, and a turbulent flow phenomenon is generated between the mixed raw materials at the intersecting portions. Let

As described above, the kneading action by the intersection of each kneading recess 13 formed in the kneading part 12 of the kneading rotary screw 5 and each spiral groove 11 of the heating cylinder 4 causes the mixed raw material to be in a proper and sufficient kneading state. After kneading, the kneading raw material is degassed in the second vent hole 7 on the tip end side, and then sequentially extruded from the extrusion port 3.

In short, each kneading concave portion 13 of the kneading rotary screw 5 formed so that the flow cross-sectional area of the raw material gradually decreases from the raw material transfer start end to the raw material transfer end end, and each spiral of the heating cylinder 4 formed in the reverse spiral direction. Since the kneading is performed while intersecting the concave grooves 11 ..., When a higher pressure than necessary is applied to the mixed raw material flowing in the respective kneading concave portions 13 of the rotary kneading screw 5, a part of the mixed raw material is applied. Is each kneading recess 13 ...
Further, the mixed raw materials flow (reverse flow) along the spiral concave grooves 12 ... of the heating cylinder 4 and flow into the spiral concave grooves 11 ... of the heating cylinder 4, so that the molecular structure of the mixed raw materials is broken by the pressure during kneading. Without kneading, it can be sufficiently kneaded while keeping its molecular weight constant.

Further, the characteristics of the mixed raw material itself are remarkably maintained in a good condition as compared with the conventional single-screw or twin-screw extruder, and each kneading concave portion 13 of the kneading rotary screw 5 and the heating cylinder 4 are kept. Of the mixed raw materials to be kneaded by the synergistic kneading action due to mutual crossing, since the fluidity does not decrease or is impaired during kneading because the fluid flows in two directions along each spiral groove 11 ... It is possible to knead in an appropriate and sufficient state according to the above.

The present invention is not limited to the configuration of the above-described embodiment.

For example, each spiral groove 1 formed in the heating cylinder 4 described above.
1 and each kneading recess 1 formed on the kneading rotary screw 5
The angle of intersection with 3 ... and the number of threads can be changed according to the type and degree of kneading of the raw materials to be kneaded, and the shape of the kneading section 12 of the kneading rotary screw 5 is the two corners of the above embodiment. It is not limited to the elliptical shape.

[Brief description of drawings]

The drawing shows one embodiment of the present invention, FIG. 1 is an enlarged cross-sectional view of a main part of a heating cylinder, FIG. 2 is a cross-sectional view taken along the line CC of FIG. 1, and FIG. FIG. 4 is an enlarged view of a main part of a kneading rotary screw and a heating cylinder, and FIGS. 5 (a) and 5 (b) are cross-sectional views taken along line AA and BB of FIG. FIG. 2 ... Input port, 3 ... Extrusion port, 4 ... Heating cylinder, 5 ... Kneading rotary screw, 11 ... Spiral groove, 12 ... Kneading section, 13 ... Kneading recess

Claims (1)

[Scope of utility model registration request] 1. An extruder in which a kneading rotary screw (5) is rotatably inserted in a heating cylinder (4) having an input port (2) at one end and an extrusion port (3) at the other end. In the kneading section (12) of the kneading rotary screw (5), a kneading recess (13) is formed in which the flow cross-sectional area of the raw material gradually decreases from the starting point of the raw material transfer to the ending point of the raw material transfer. A spiral groove (11) whose screwing direction is opposite to the screwing direction of the kneading rotary screw (5) is formed on the inner peripheral surface of the heating cylinder (4) corresponding to substantially the entire width of (12). Formed extruder.