JPS6037779B2 - Two-layer extrusion head structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a two-layer extrusion head structure, and more particularly to a two-layer extrusion head structure suitable for two-layer extrusion using different types of polymeric materials having significantly different extrusion temperatures.

Extruding two layers of different types of polymeric materials is possible by sharing an extrusion head and using the same temperature control mechanism.

However, this is limited to cases where the extrusion temperatures of different polymeric materials are similar; as in the case of rubber and synthetic resin, the extrusion temperature of the former is 50 to 10,000 and the latter is 160 to 20,000 at the head adjustment temperature. If the difference was large, it was considered impossible to extrude two layers. In other words, if two layers of rubber and synthetic resin are extruded using the same extrusion head and the same temperature control mechanism, rubber burns may occur, or
Insufficient melting of the synthetic resin may occur, or both may occur, making extrusion virtually impossible. In view of the above, an object of the present invention is to provide a two-layer extrusion head structure capable of two-layer extrusion using different types of polymeric materials having significantly different extrusion temperatures.

The gist of this invention is a structure used for double-layer extrusion using different types of polymer materials with different extrusion temperatures, in which one material flow path directly connected to a die orifice is formed with a heat insulating material, and each polymer material It has a two-layer extrusion head structure with a separate overflow control mechanism in the material head.

Hereinafter, one embodiment of the present invention will be described based on illustrated examples.

As shown in FIGS. 1 to 4, the two-layer extrusion head has a cross-head structure of a rubber head section 1 and a synthetic resin head section (hereinafter referred to as "resin head section") 11. The rubber head section 1 includes a cylindrical rubber head main body 2, a torpedo 3 for rubber rectification, and a torpedo 3 connected to the rubber head main body 2.
It consists of a flow block 4 and a block holding nut 5 for attachment to the block.

Further, a hot water flow path 6 is provided on the outer periphery of the rubber head main body 2 and is provided with a temperature sensing part (not shown) for temperature control in the middle.
At the tip of the flow block 4 of the rubber head section 1, a heat insulating cylinder (insulation material) 10 are arranged,
A resin head portion 11 having the following configuration is attached via a heat insulating joint 10.

The heat-insulating cylindrical body 10 is made of, for example, asbestos impregnated with phenol resin and compression-molded, and has a thermal conductivity of 0.1 to 0. Arc cal/m. h. Any material can be selected as long as it has heat resistance and rigidity at qo.

The resin head section 11 includes a die section 12 which is provided continuously across the heat insulating cylinder, and a die section 12 for assembling the die section 12 together with the heat insulating cylinder 10 into the rubber head section 1 and guiding the resin to the die section 12. a barrel 13; and a resin head body 1 that is attached crosswise to the barrel 13 and has an extruder connection part 14 at one end.
It consists of 5.

The barrel 13 is assembled to the block retainer nut 5 with a barrel retainer nut 16, and the resin head main body 15 is fixed to the barrel 13 with a fixing nut 17. At this time, O rings 19 are attached to both sides of the resin flow path 18 of the iron joint portion of the barrel 13 and the resin head main body 15 in order to prevent the resin from leaking to the outside. Further, cartridge heaters 21 are attached at six locations, four on the resin head main body 15 and two on the barrel 13. 22 is
This is a thermosensing part for fully adjusting the resin head.

The die section 12 also includes a first extrusion die 24 for rubber extrusion and a second extrusion die 24 for integral extrusion of rubber and resin, as shown in FIGS.
It consists of an extrusion die 25. Figures 5 and 6 show the former die 24.
The A and B arrow views, respectively, and Figures 7 and 8 show the latter die 25.
These are views taken along arrows A and B, respectively. Note that 26 is a first orifice, 27 is a resin reservoir, 28 is a resin inlet, and 29 is a second orifice. Next, two-layer extrusion using the head structure with the above configuration is performed, as shown in FIG.
The explanation will be given by taking as an example a band-shaped product 32 in which a resin layer 31 is coated on top of the belt-shaped product 32.

Similar to general two-layer extrusion, rubber and resin are delivered from separate extruders (not shown) and advance to the die section 12.

That is, the rubber is inserted into the torpedo 3 inside the rubber head body 2.
The flow is rectified by the flow, and further reaches the first orifice 26 of the die portion 12 via the rubber flow path 8 of the heat insulating cylinder 10.

Naturally, the temperature of the rubber head portion 1 is controlled by the hot water flow path 6. Further, the resin is supplied from inside the resin head main body 15 to the resin flow path 18 of the barrel 13 and the resin inlet 2 of the die section 12.
8. The resin reaches the second orifice 29 via the resin reservoir 27.

In the die part 12, a rubber layer 30 is formed by the first orifice 26, and a rubber layer 30 is formed by the second orifice 29.
Two layers are extruded while a resin layer 31 is formed on top of the resin layer 31 .

Naturally, the temperature of the resin head section 11 is controlled by the cartridge heater 21. At this time, there is a large difference in temperature control between the rubber head section 1 and the resin head section 11 (for example, when the rubber
When the resin is polyethylene in PDM, 90q○ and 200
qo), heat transfer between the rubber head part 1 and the resin head part 11 is prevented from the heat insulating cylinder 10' until just before the rubber and resin are sulfurized into the first and second orifices 26 and 29, respectively. , each have little effect on temperature regulation,
Individual temperature control becomes possible, solving problems such as rubber burning or insufficient melting of resin.

Note that the rubber head part 1 and the resin head part 11 are in contact with each other through one end of the block holding nut 5, the barrel holding nut 16, and the barrel 13 in addition to the insulating cylinder 10, and the contact area is is small and the contact point is far from the material flow path (rubber and resin), so the influence of each temperature adjustment effect on each other can be ignored. Moreover, the die part 12 is
Since it is attached to the resin head part 11 side, the temperature is high, but since the time for the rubber to pass through the orifices 26 and 29 is short (1 second or less), the rubber does not burn.

In the embodiment described above, the reason why the heat insulating cylinder 10 was provided immediately before the die part 12 so as to form a rubber flow path is because rubber tends to accumulate in this part and cause rubber burning.

If the resin and rubber head parts are configured in the opposite way, the installation position and shape of the insulation material will change, but it is still within the scope of the technical concept of forming one of the material flow paths directly connected to the die orifice with the insulation material. You can design it with In addition, in the case of continuous molding for a long period of time (for example, one week), heat dissipation fins are provided on the block holding nut 5, or the holding nut 5 is
Through holes are made in several places from the outer circumference to the inner circumference of the heat insulating cylinder 10, and when the temperature reaches a high temperature, cold air is blown into the through holes, or both are used in combination to heat the heat insulating material. Heat dissipation may be promoted.

Since the two-layer extrusion head structure of the present invention has the above-described configuration, the temperature of each head portion can be controlled individually, and two-layer extrusion of different types of polymeric materials with significantly different extrusion temperatures becomes possible.

The applicable products are not limited to band-shaped products as mentioned above, but can also be applied to hose coverings, etc. Also, the applicable products are not limited to combinations of rubber and resin, but even if the resins are mutually extruded. If the head structure of the present invention is employed when the temperatures are significantly different, smooth two-layer extrusion becomes possible and effective.

[Brief explanation of the drawing]

1 is a front view of a head according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the Rollo line in FIG. 1, FIG. 3 is an enlarged view of the die portion in FIG. 2, and FIG. 5 is a cross-sectional view taken along line W-W, FIG. 5 is a view of the first extrusion die in the direction of arrow A in FIG. 4, and FIG.
Fig. 7 is a view of the second extrusion die in the direction of the A arrow in Fig. 4, Fig. 8 is a view of the second extrusion die in the direction of the B arrow, and Fig. 9 is a view of the second extrusion die in the direction of the B arrow. FIG. 2 is an enlarged cross-sectional view of an extruded product. 1...Rubber head part, 2...Rubber head body, 6...
... Hot water flow path (temperature control mechanism), 10 ... Heat insulation cylinder, 11 ... Synthetic resin head section, 12 ... Die section, 13 ... Barrel, 15 ... Resin head body, 21 ... Cartridge heater, 26 ... First orifice (die orifice), 29 ... Second orifice (die orifice), 30 ... Rubber layer, 31 ... Resin layer, 32...Band-shaped product (two-layer extruded product). Figure 1 Figure 3 Figure 4 Figure 5 Figure 2 Figure 6 Figure 7 Figure 8 Figure 9

Claims (1)

[Claims] 1 A head structure used to extrude two layers of different types of polymeric materials with different extrusion temperatures, in which one material flow path directly connected to the die orifice is formed of a heat insulating material, and the head of each polymeric material is A two-layer extrusion head structure characterized by having a separate temperature control mechanism.