JPS6299130A - Screw - Google Patents

Abstract

PURPOSE:To make the difference of phase to the rotation of resin flowing in each of the channels at the outlet to enable the resin to be replaced and dispersed effectively by arranging the fins of non-equal length to the direction of axis and providing the channels having substantially different lengths between the fins in the Dulmage mixing device. CONSTITUTION:At the fin section of a Dulmage mixing device, in which the fins 11 of non-equal length and the sections carrying no fin 11a are arranged to the direction of screw rotation of the single axial extruder alternatively. The resin 13 flowed in from the foregoing screw proceeds through the channel spirally being rotated by the rotation of screw. The spiral pitch between each of the channels are same, but the rotating phase of the resin 13 can be shifted at the inlet and out of each of channels by altering the length of fin 11 and providing different length of channels substantially between each of the channels. By the said process, the resin 13 can be replaced and dispersed effectively in the screw.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a screw that can be used in a single-screw extrusion molding machine.

(Prior art) A screw for a single-screw extrusion molding machine is required to melt raw materials, homogeneously knead them, disperse them, and extrude them.A general screw S, as shown in FIG. It is roughly divided into a solid transportation section A, a plasticization section B, and a weighing section C depending on the plasticization process.

Conventionally, in the weighing section C, there was a full-flight souffriere in which one or more flies l-1 were provided in a spiral shape on a cylinder, as shown in Fig. 6 and Fig. 713 (developed view of Fig. 6). It was used. Further, 2 is the flow direction of the molten resin.

In recent years, in order to further improve the crosstalk and dispersion properties of full-flight screws, the tip of the screw has been designed to have the same length in the screw axial direction as shown in Figures 9 and 10 (developed view of Figure 9). It has been considered to install a dalmage type screw 4 in which fins 3 having fins 3 are arranged in the direction of rotation of the screw.

However, in the full-flight screw, the molten resin flows within the groove 5 as shown in FIG. That is, the resin 6 that has been subjected to heat transfer from the cylinder wall surface is scraped off by the rotating screw flight as shown in 7, and descends along the pushing flight 8. Subsequently, it flows along the bottom of the groove as indicated by 7', returns to the cylinder wall along the pulling flight 9, and further moves as indicated by 7a. In particular, in the case of deep grooves, the resin 10 flowing in the center of the flow path was not replaced sufficiently, which tended to cause temperature unevenness and kneading unevenness.

Further, in the Dalmage type screw, as shown in FIG. 11, the water flows in the valley groove between the fins 3 in the same manner as in the full-flight screw. In other words, even if the resin 6 rotates in the groove between the fins due to the fins 3 of equal length provided in the direction of the screw axis, the phase of the resin rotation at the entrance and exit is the same in the valley groove, so there is no effect. It was not possible to perform proper resin replacement or dispersion.

(Problems to be Solved by the Invention) Conventional injection molding screws have problems such as insufficient resin replacement, which tends to result in uneven temperature and kneading, and ineffective resin replacement and dispersion. There have been problems and the present invention seeks to solve these problems.

Therefore, the present invention provides a fin portion of a Dalmage type mixing machine in which fins arranged in the screw rotation direction of a single-screw extruder screw and portions without fins alternate in the axial direction. , which consists of fins of unequal length arranged in the direction of rotation,
This is a means to solve problems.

(Function) The resin flowing from the front screw rotates while moving forward in the groove due to the rotation of the screw, and exhibits a spiral flow with respect to the groove. The pinch of this helix is the same between each groove, but by changing the length of the fin and making a difference in the actual groove length between each groove, the inlet and outlet of the resin between each groove is It is possible to shift the phase of rotation.

This action allows effective substitution and dispersion of resin within the screw.

(Example) Examples of the present invention will be described below with reference to the drawings. FIGS. 1 to 4 show examples of the present invention.

In the figure, 12 is a dalmage, and fins 11. The fins Ila are arranged alternately in the direction of rotation, and the flow of the resin 13 within the fins is as shown in FIG. Also, is the height of the fin the same as that of Full Flight 1?
It shall be less than that. Further, the resin 13 supplied from the raw material supply section and plasticized and melted through the solid transportation section, plasticization section, and pre-stage metering section is supplied to the screw tip of the present invention.

In FIG. 4, the resin 13 on the cylinder wall side that has entered the fin portion as shown by the arrow 14 is first sown by the fin 11a, moves to the bottom of the groove, flows toward the fin 11 as shown at 15, and then flows to the fin 11 as shown at 14a. By flowing like this, it flows in the groove between the fins 11 and 112 in a spiral manner. Further, the resin 13a on the cylinder wall side is also scraped off by the fins 11a, moves to the groove bottom, and then flows in the groove between the fins 21a and 11 while rotating. In addition, resin 13.132 flowing between the fins
Although the helical pitch 4 of the flow is the same, the actual groove length is different for 13 and 138, so the resins 13 and 13
In No. 3, the phase of rotation is shifted at the exit, and the position of the groove in the depth direction is different. Therefore, the resin is effectively replaced and dispersed in the screw section of the present invention, and as a result, homogeneous extrusion becomes possible and the performance of the extruder is improved.

(Effects of the Invention) As described above in detail, the present invention arranges fins of unequal length in the axial direction in the rotational direction in Dalmage type mixing, and reduces the difference in the substantial groove length of the grooves between the fins. By attaching the grooves, a phase difference is created at the groove outlet with respect to the rotation of the resin flowing in each groove, and the resin can be effectively replaced and dispersed.

[Brief explanation of drawings]

Fig. 1 is a side view of the tip of a dalmage screw showing an embodiment of the present invention, Fig. 2 is a developed view of Fig. 1, Fig. 3 is a side view of the invention applied to a general screw, Fig. 4 5 is a perspective view of a part of a screw schematically showing the flow of resin in the screw groove according to an embodiment of the present invention; FIG. 5 is an overall side view showing a part of a conventional extruder in cross section; FIG. Figure 6 is a side view of a conventional full flight screw, Figure 7 is a developed view of Figure 6, and Figure 8 is a part of the screw schematically showing the flow of resin in the groove of a conventional full flight screw. A perspective view, FIG. 9 is a side view of a conventional Dalmage screw, FIG. 10 is a developed view thereof, and FIG. 11 is a perspective view of a part of the screw schematically showing the flow of resin in a conventional Dalmage screw. It is a diagram. Explanation of main parts of the diagram 11-Fin 11a...-Fin 12-Dulmage 13-Resin patent Applicant Mitsubishi Heavy Industries, Ltd.Figure 1Figure 2Figure 11

Claims (1)

[Claims] It is characterized by fins of unequal length being arranged in the direction of rotation in the fin section of Dalmage type mixing, where fins lined up in the direction of screw rotation of a screw for a single-screw extruder and parts without fins alternate in the axial direction. screw.