JPH0655611A - Double-screw extruder for volatilizing non-thermoplastic rubber - Google Patents

Abstract

PURPOSE:To provide a double-screw extruder for volatilizing non-thermoplastic rubber which can volatilize sufficiently a non-thermoplastic rubber material. CONSTITUTION:In a double-screw extruder 6 for volatilizing non-thermoplastic rubber comprising prefect meshing double-screws 21 rotating in the different directions for extruding a material by the rotation in a barrel 22 provided with a volatilizing openings 23 and gears 1 and 2 inserted into the position just before the volatilizing openings 23 of respective screws 21 and having a plurality of teeth on the peripheral faces and meshed with each other, the teeth of the gears 1 and 2 are formed by the teeth of recessed and projected lines 3. Also in the double-screw extruder for volatilizing non-thermoplastic rubber 6, the intervals of recesses and projections of teeth of recessed and projected lines 3 of the gears 1 and 2 meshed each other are preferably diviated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-thermoplastic rubber devolatilizing twin-screw extruder for devolatilizing a high-viscosity non-thermoplastic rubber material such as SBR.

[0002]

2. Description of the Related Art As shown in FIG. 5, a conventional devolatilizing twin-screw extruder 26 has a variable pitch in a barrel 22 provided with a feed port 25 for feeding a material and a devolatilizing port 23 on its upper surface. 2 has a trapezoidal screw 24 having the same depth and is completely meshed in the axial direction with two screws 21 rotating in different directions. The pitch of the trapezoidal screw 24 is set to a wide pitch P1 in the material supply port 25 in order to increase the transport volume per one rotation, and gradually narrowed toward the devolatilization port 23 so that the material is well kneaded by compression. The pitch P2 is the narrowest before the devolatilization port 23. The devolatilization port 23 has a wide pitch P3 so as to loosen the compression of the material that has been compression-kneaded and volatilize, and the devolatilization port 23 to the discharge port 22.
The pitch P4 is gradually narrowed again so that the material can be extruded from a die or the like as it goes to a.

The conventional devolatilizing twin-screw extruder 26 configured as described above continuously feeds the barrel 22 from the supply port 25.
Material is supplied inside. Then, while the material is being heated by the heat from the barrel 22, the material is moved and sheared and compressed by the rotation of the screw 21. Then, the volatilization port 23 is used to reduce the filling degree of the material into the screw 21, and unnecessary components such as water and monomers contained in the material are forcibly removed by a vacuum pump or the like for volatilization. After that, the material feed amount is adjusted and the material is quantitatively extruded from the discharge port 23a.

[0004]

However, when the material is a non-thermoplastic rubber such as SBR, the viscosity does not decrease even if the temperature of the material rises and the fluidity is poor, so that the conventional twin screw extruder for devolatilization is used. With the screw 21 of the machine 26, almost no surface renewal of the material is obtained, and there is a problem that sufficient devolatilization is not performed. Therefore, it is conceivable to use a kneading gear which has a plurality of straight convex teeth on the peripheral surface and meshes with each other and inserts the kneading gear into the screw to improve the surface renewal. However, this kneading gear has a shape suitable for increasing the kneading degree of the material, and it is difficult to divert it as it is to improve the surface renewal of a material having poor fluidity such as non-thermoplastic rubber. It has a simple shape.

The present invention has been made in view of the above problems of the prior art, and an object thereof is to remove a non-thermoplastic rubber capable of sufficiently devolatilizing a non-thermoplastic rubber material. It is intended to provide a twin screw extruder for volatile matter.

[0006]

In order to solve the above-mentioned problems, a non-thermoplastic rubber devolatilizing twin-screw extruder according to the present invention has a barrel having a devolatilizing port, in which a material is extruded by rotation in different directions. Non-thermoplastic rubber comprising a completely meshing twin-screw screw, and a gear inserted into a position immediately before the devolatilization port of each screw and having a plurality of teeth on its peripheral surface and meshingly engaged with each other. In the devolatilizing twin-screw extruder, the teeth of the gear are formed by teeth of uneven lines.

Further, in the above-mentioned non-thermoplastic rubber devolatilizing twin-screw extruder, it is preferable that the tooth irregularities of the concavo-convex strips of the gears meshing with each other are displaced.

[0008]

[Function] When the teeth of the gear are formed by the teeth of the uneven strips, the screw-like rotation causes the string-shaped non-thermoplastic rubber material between the strips to be finely chopped into diced teeth and then subdivided. Increase the surface area and renew the surface. Further, by shifting the intervals of the concavo-convex teeth of the concavo-convex stripes of the gears that mesh with each other, fine cutting is surely performed.

[0009]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a twin-screw extruder 6 for devolatilizing a non-thermoplastic rubber of the present invention.
FIG. 3 is a view showing a main part of FIG. 1, in which gears 1 and 2 inserted into a screw 21 are shown. 2 is a sectional view taken along line AA of FIG. 1, FIG. 3 is a sectional view taken along line BB of FIG. 1, and FIG. 4 is a sectional view taken along line CC of FIG.

As shown in FIG. 1, the non-thermoplastic rubber devolatilizing twin-screw extruder 6 of the present invention has a devolatilizing port 2 of each screw 21.
A pair of gears 1 meshingly engaged with each other at a position immediately before 3.
2 is inserted. Other parts are the same as those described in FIG.

The pair of gears 1 and 2 are helical gears, and as shown in FIG. 3, teeth 3 and grooves 4 which mesh with each other.
And have. Then, as shown in FIG. 2, the tooth 3 has an uneven strip 3 provided with a large number of notches 5 in the longitudinal direction.
Has become. Further, as shown in FIG. 4, the notch 5a of the gear 1 and the notch 5b of the gear 2 are displaced in the longitudinal direction.

As described above, when the teeth of the gears 1 and 2 of FIG.
The non-thermoplastic rubber material accumulated in the form of a strip is formed into strips by the teeth of the ridges and valleys 3 and further finely chopped into dices, and the surface area is increased by subdividing, resulting in remarkable surface renewal. Then, the gears 1 and 2 on which the surface is updated
Since the devolatilizing port 23 is provided so as to come into contact with, the unnecessary components such as water and monomers generated by the surface renewal are efficiently devolatilized. Further, as shown in FIG. 4, when the gaps between the recesses and protrusions 5a and 5b of the concavo-convex strips of the gears 1 and 2 which mesh with each other are shifted, the interference between the concavo-convex strips does not hinder the fine cutting.

Although a pair of gears is used in the embodiment, a plurality of pairs of gears may be arranged in series. In addition, the teeth of the concavo-convex stripes of the gear are helical teeth in the embodiment, but may be flat teeth.

[0014]

INDUSTRIAL APPLICABILITY The non-thermoplastic rubber devolatilizing twin-screw extruder of the present invention has a high-viscosity non-thermoplastic rubber material of high viscosity, which is formed by forming the teeth of the gears with the teeth of concave and convex lines. As it rotates, it is finely chopped into diced pieces and subdivided to increase the surface area immediately before the devolatilizing port to remarkably renew the surface. As a result, the non-thermoplastic rubber material is sufficiently devolatilized.

[Brief description of drawings]

FIG. 1 is a view showing a main part of a non-thermoplastic rubber devolatilizing twin-screw extruder of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG.

FIG. 4 is a sectional view taken along line CC of FIG.

FIG. 5 is a view showing an entire conventional twin-screw extruder for devolatilizing non-thermoplastic rubber.

[Explanation of symbols]

 6 Non-thermoplastic rubber devolatilizing twin-screw extruder 1, 2 Gears 3 Concavo-convex strip 21 Screw 22 Barrel 23 Devolatilizing port

Claims (2)

[Claims] 1. In a barrel having a devolatilizing port, a counter-rotating complete meshing twin-screw screw that pushes material forward by rotation, and a peripheral surface of each screw inserted immediately before the devolatilizing port. In a twin-screw extruder for non-thermoplastic rubber devolatilization, which comprises a gear having a plurality of teeth and meshingly engaged with each other, the teeth of the gear are formed by teeth of uneven lines. Twin screw extruder for devolatilizing non-thermoplastic rubber. 2. The non-thermoplastic rubber devolatilizing twin-screw extruder according to claim 1, wherein the tooth irregularities of the concavo-convex strips of the gears meshingly engaged with each other are displaced from each other. Twin screw extruder for devolatilizing plastic rubber.