JPS5933626Y2 - extruder - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to an extruder.

Conventional extruders include a conventional screw consisting of a feed section F and a metering section M as shown on the first page, or a two-stage screw, a polygonal type as shown in Figs. 3 to 6, and a polygon type as shown in Fig. 7. A second flute mixing type with a special mixing section Mi of the type shown in FIGS. 8, 9 and 10 in the middle.
It is equipped with the two-stage screw shown in the figure, and the groove depth Hl of the feed section F is deeper than the groove depth H2 of the metering section M in both screws. In an extruder using a screw, crosstalk,
Dispersion and extrusion stability can be expected, but the disadvantage is that the resin temperature becomes high, the rotation speed cannot be increased unnecessarily, and the extrusion amount per rotation speed itself cannot be expected. In an extruder using an extruder, the groove in the metering part is deep to some extent, and although it can be expected to increase the extrusion amount and extrude at a low resin temperature, it causes crosstalk and poor dispersion, resulting in poor extrusion stability (especially pressure dependence). There is a drawback that it lacks, and the second
An extruder using a two-stage screw with a special mixing section Mi as shown in the figure has the disadvantage that even if crosstalk is improved, extrusion stability deteriorates when trying to further increase the extrusion amount. was there.

Therefore, the purpose of this invention is to provide an extruder that can perform high-capacity extrusion, low resin temperature extrusion, high kneading, high dispersion, and highly productive extrusion with excellent extrusion stability by improving the screw. It has been done.

Next, the present invention will be specifically explained based on an embodiment shown in FIG.

In the same figure, there is a raw material feeding section F with a shallow groove depth and a tip metering section M with a deep groove depth, and in the middle thereof there is a mixing section like a polygonal screw with high kneading and high plasticizing functions. Mi is provided, and raw material feed section F
The jingle screw 1 has a groove depth Hl equal to or shallower than the groove depth H2 of the metering part M.

In the raw material feed section F with a shallow groove depth, the extrusion amount per rotation speed is controlled at a constant level without being affected by the high or low rotation speed, the tip pressure or pressure fluctuation, and the mixing section Mi installed in the middle prevents crosstalk. , dispersion, and melting, and in the tip metering part M with a deep groove, the rise in resin temperature is suppressed, the resin physical properties are stabilized, and the resin is extruded at a low resin temperature.

The raw material feed section F with a shallow groove depth allows the extrusion amount per revolution to be controlled at a constant level without being affected by the tip pressure or the revolution speed, ensuring extrusion stability and providing a powerful feed for the mixing section Mi. By having a plasticizing function, it compensates for the decrease in melting ability caused by shallowing the groove depth of the raw material feed section F, and at the same time makes it possible to achieve high kneading and high dispersion.

In the normal case, this has a plasticizing ability by providing a groove depth ratio H1/H2 between the feed section F and the metering section M, that is, a so-called compression ratio.

If the compression ratio is too small, the plasticizing ability will be reduced, resulting in extrusion without melting or insufficient cross-linking.

The polygonal screw cylinder has a tip metering part M with a deep groove depth that sufficiently compensates for this, suppressing the rise in resin temperature, stabilizing the resin physical properties, extruding at a low resin temperature, and increasing the groove depth H of the feed part F. Because it is shallow, the raw material is fed into the mixing section Mi almost unmolten, so there is no disturbance of the raw material flow due to break-up phenomena in the feed section F, and uniform melting and kneading is performed in the mixing section Mi. There is no galling between the cylinders, and when extruding in this example, the pressure inside the cylinder suddenly increases from around the end of the feed section F, and the raw material is compressed rapidly, as if the compression ratio (H1/H2) had been increased. As soon as the material begins to melt, the air in the gaps between the raw materials escapes toward the supply port, so there is no air entrainment, and there is no need to worry about air bubbles being mixed into the extruded product.

Next, the diameter is 90φmm, L / D = 27, the cross section uses a hexagonal screw and cylinder, and the groove depth ratio is Ho
:H2=1 :HDPE using 1.125 screw
Tables 1 and 2 show the results of an experiment comparing the extruder of this example using pelletized resin with a conventional extruder.

Comparing Tables 1 and 2, we can see that the degree of kneading and extrusion stability are relatively good, and the extrusion amount is also good.Comparing the extruder with a conventional screw and the extruder based on this example, it is still true. It can be seen that the resin temperature is high and the amount of extrusion per rotational speed is low.

In this example, the screw is a jingle screw, but 2
It may be a stage screw, and the shape of the mixing section Mi may be any of the types shown in FIGS. 3 to 11.

As described in detail in the embodiments above, the present invention has a mixing section with high kneading and high plasticizing functions between the raw material feed section and the tip metering section in the screw of a single screw extruder, and By providing an extruder characterized in that the metal ring part and the screw are provided with a screw whose groove depth is deeper than the groove depth of the feed part, the tip pressure can be reduced by the raw material feed part with a shallow groove depth. By controlling the extrusion amount per rotational speed at a constant level without being affected by the size of the This makes it possible to compensate for the decrease in melting ability that occurs due to the shallow groove depth, and at the same time achieve high kneading and high dispersion. The physical properties are stabilized and the material is extruded at a low resin temperature, and the depth of the groove in the feed section is shallow, so the raw material is fed into the mixing section almost unmolten, so there is no disturbance of the raw material flow due to break-up phenomena in the feed section, etc. In addition, uniform melting and mixing occurs in the mixing section, eliminating galling between the screw and cylinder.Furthermore, when the raw material is extruded, the pressure inside the cylinder suddenly increases from the end of the feeding section, as if the compression ratio ( The raw material is rapidly compressed and begins to melt as if the H, /H2) were increased, and the air in the gaps between the raw materials escapes toward the supply port, so there is no air entrainment, and there is no need to worry about air bubbles being mixed into the extruded product. It is something.

[Brief explanation of the drawing]

Figures 1 and 2 are explanatory diagrams showing the screw of a conventional extruder, Figures 3 to 10 are illustrations of the shape of the mixing section of the seed screw, and Figure 3 is an explanatory diagram thereof. , FIG. 4 is a sectional view taken along line A-A in FIG. 3, FIG. 5 is an explanatory diagram of another conventional mixing section, FIG. 6 is a sectional view taken along line B-B, FIGS. 8, 9, and 10 are respectively explanatory diagrams of still other conventional mixing sections, FIG. 11 is an explanatory diagram as seen from the direction of arrow C-C in FIG. It is an explanatory diagram showing one example. 1: Screw, F: Feed section, M: Metering section,
Mi: Mixing section.

Claims (1)

[Scope of utility model registration request] A mixing part having a high kneading and high plasticizing function is provided between the raw material feed part and the tip metering part, and the groove depth of the metering part is deeper than the groove depth of the feed part. An extruder characterized by being equipped with a screw.