JPH10217312A - Screw of double worm extruder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable inhibition of heat build-up of resin by making front shape of a orthogonal section of a transmission part screw flight into a right angle and rear shape into a curved surface. SOLUTION: A screw flight 2B of a screw 2A in a transmission part has front shape of a right-angled face L on the orthogonal section with respect to the screw flight 2B direction, and rear shape of curved face. Each of the screw flights 2B is separated axially for increasing a gap of an intermeshed part 2C between each screw 2A. As a result, resin is extruded through a front face of the screw flight 2B and moved toward downstream side. Since a large gap is formed between the front face L of one screw flight 2B and a rear face R, of the other screw flight 2B, heat build-up of resin in a transmission area is inhibited.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw for a twin-screw extruder, and more particularly, to kneading, degassing, and mixing a resin.
The present invention relates to a meshing screw of a twin-screw extruder suitable for granulation.

[0002]

2. Description of the Related Art A conventional twin screw extruder will be described with reference to FIG.

FIG. 3 is an overall configuration diagram of a meshing co-rotating twin-screw extruder. FIG. 3 (a) is a cross-sectional plan view of a main part, and FIG. 3 (b) is a cross-sectional side view of a main part.

In FIG. 3 (a), a cylinder indicated by reference numeral 1 is a cylinder, and an inner hole of the cylinder 1 is provided with a meshing type biaxial screw 2 which rotates in the same direction. A hopper cylinder 3 is attached to the rear of the cylinder 1, and a hopper 4 for supplying a raw material is disposed above the hopper cylinder 3. The biaxial screw 2 is rotatable by a motor 6 via a speed reducer 5 provided at the rear of the hopper cylinder 3.

[0005] A die 8 is attached to the tip of the cylinder 1 via an adapter 7, and a cutting device 9 is attached to the adapter 7.

As shown in FIG. 3 (b), the screw 2 of the twin-screw extruder usually has a supply section F, a kneading section M, a transport section (or measuring section) T, etc. from the upstream side. A completely meshing type full flight screw is used for the screw 2a of the transport section.

FIG. 4 is an external view showing a segment of a completely meshing screw, 4 (a) is a plan view, and 4 (b) is a side view. It should be noted that a plurality of these segments are fitted to the hexagonal central shaft to form a complete mesh type full flight screw.

FIG. 5 is a sectional view taken along the line BB of FIG. 4 (a), showing the shape of the screw flight. As shown in FIG. 5, the screw flight 2b of the screw 2a in the transport section has a curved surface R1 in a cross section perpendicular to the direction of the screw flight 2b, and a curved surface R2 in a rear surface. As described above, since the curved surfaces R1 and R2 are formed on the front surface and the rear surface of the screw flight 2b, the gap between the meshing portions 2c of the screw 2a is reduced as shown in FIG.
As shown in FIG.

[0009]

Conventionally, since the above-described full-engagement type full flight screw is used for the screw in the transporting section, the gap between the meshing sections of the screw is reduced, and the resin generates heat at the meshing section. As a result, there is a problem that the temperature of the resin increases.

[0010] The present invention has been made to solve the above problems, and an object of the present invention is to provide a screw of a twin-screw extruder capable of suppressing heat generation of a resin in a screw of a transport section.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described based on embodiments with reference to the drawings.

FIG. 1 is an external view showing a segment of a meshing type screw according to the present invention, and FIG.
FIG. 1B is a side view. FIG. 2 is a cross-sectional view of FIG.
FIG. 3 is a sectional view taken along line A, showing a shape of a screw flight. The twin-screw extruder having the screw is the same as that described with reference to FIG. 3 in the section of the prior art, and the description thereof is omitted.

As shown in FIGS. 1 and 2, the screw flight 2B of the screw 2A in the transport section has a front surface having a right-angled surface L and a rear surface shape in a cross section perpendicular to the direction of the screw flight 2B. Is a curved surface R.

The screw flights 2B of the screw 2A are arranged so as to be separated in the axial direction. Due to the above-described configuration of the screw flight 2B, the gap between the meshing portions 2C between the screws 2A is increased as shown in FIG.

Next, the operation of the above-described screw will be described.

In FIG. 3, the resin supplied from the hopper 4 to the hopper cylinder 3 is fed to the kneading section M via the supply section F by the intermeshing type biaxial screw 2 and melted.
Kneaded. Then, it is sent to the transport part T and made uniform. The homogenized resin that has been melted and kneaded is extruded in a string form from a die 8, cut by a cutting device 9, and pelletized.

In the transport zone T, the resin is pushed by the front surface of the screw flight 2B and moves downstream, but the front surface (right angle surface) L of one screw flight 2B and the rear surface (right surface) of the other screw flight 2B. Since a large gap is formed between the (curved surfaces) R, heat generation of the resin in the transport zone T can be suppressed.

Next, conditions and results of the extrusion test will be described.

(A) Raw material: ABS (b) Extruder: Meshing type co-rotating twin screw extruder, Co., Ltd.
Nippon Steel Works, model TEX65, screw diameter 69 mm (c) Results: Table 1 shows.

[0020]

[Table 1]

[0021]

As described above, the screw in the transport section of the twin-screw extruder according to the present invention is configured as described above, so that heat generation of the resin can be suppressed and the temperature of the extruded resin can be reduced.

[Brief description of the drawings]

FIG. 1 is an external view showing a segment of a meshing screw according to the present invention, wherein FIG. 1 (a) is a plan view and FIG. 1 (b) is a side view.

FIG. 2 is a cross-sectional view taken along line AA of FIG. 1 (a), showing a shape of a screw flight.

FIG. 3 is an overall configuration diagram of a meshing type co-rotating twin-screw extruder, and FIG.
(B) is a sectional side view of a main part.

FIG. 4 is an external view showing a segment of a conventional fully meshing screw, in which FIG. 4 (a) is a plan view and FIG. 4 (b) is a side view.

FIG. 5 is a sectional view taken along line BB of FIG. 4 (a), showing the shape of a screw flight.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder 2 Screw 2A Screw of transport section 2B Screw flight L Right angle surface R Curved surface K Meshing section T Transport section

Claims (1)

[Claims] 1. A screw flight (2) of a transport section (T) in a screw of a meshing type co-rotating twin screw extruder.
B) A twin-screw extruder characterized in that the front surface in a cross section perpendicular to the direction of the screw flight (2B) has a right-angled surface (L) and the rear surface has a curved surface (R). Screw.