JPS5947075B2 - Method for manufacturing polyolefin rope - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing polyolefin ropes.

Conventionally, polyolefin ropes have been produced by, for example, twisting three strands to form a rope, then winding the rope, adding water in a separate process, and subjecting the rope to heat treatment by shading a high-frequency electric field.

The purpose of heat treatment is to eliminate the repulsive force caused by the twisting inside the rope, prevent the rope from crumbling and kinking, increase flexibility, and suppress deterioration over time. By heating the rope to a temperature slightly below the softening point of the material, the direction of the molecular arrangement is corrected in the direction of twisting, so that the twisted state is the natural state for the molecular arrangement of the rope. The idea is to cool it down and fix it in that state to eliminate the repulsive force.

Note that "kink" refers to the three strands that make up the rope being twisted by the repulsive force caused by twisting due to rapid expansion and contraction of the rope.

In addition, the reason why water was conventionally added to the rope during high-frequency heating is that polyolefin materials do not have polar groups like water, so there is no dielectric loss due to high frequencies (therefore, there is almost no dielectric loss even under high-frequency electric fields). Since there is no internal heat generation, water is added to generate heat, and the generated water causes
This is to heat the rope.

However, in the conventional method, the pressure at the part where the high-frequency electric field is shaded cannot be raised above atmospheric pressure, and the water temperature can also be raised above IOO'C, so that almost no effect of heat treatment can be expected.

This is because 100°C is a temperature far below the softening point of polyolefin materials such as polypropylene.

In addition, with conventional methods, water adhesion is highly uneven, and therefore uniform heat treatment cannot be expected.

The present invention has been developed in view of these shortcomings of conventional methods and provides a method for producing polyolefin ropes that features effective heat treatment to produce flexible and long-lasting ropes.

That is, the present invention is characterized in that the polyolefin strand 2 is made into a rope 6, and then the rope 6 is heat-treated by passing it through steam 10 while keeping the rope 6 under tension to the extent that it does not loosen. This is a method for manufacturing a rope 6.

The present invention will be described below with reference to the drawings.

As mentioned above, the feature of the present invention is that the rope 6 is heat treated with steam 10.

Therefore, if, for example, the condition that three strands 2 are made into a rope 6 and then heat treated with steam 10 is satisfied, the inside of the steam heating tube 9 will be heated as shown in FIGS. 1 and 2. Even if heat treated with steam 10,
Alternatively, even if the heat treatment is carried out in a container 9' that utilizes the equilibrium between water pressure and steam pressure (hereinafter referred to as "hydraulic container 9'") as shown in Fig. 4, there is no essential difference in the effect. .

The reason why the rope 6 is kept under tension during heat treatment is to heat-treat the rope 6 in a straight state, and for this purpose, as shown in FIGS. One method is to tension the rope 6 by means of the capstan roll 7 and the rear capstan roll 7'.

First, a case where the rope 6 is heat treated using the steam heating tube 9 will be described.

1 and 2 show a state in which a steam heating pipe 9 is installed between a front capstan roll 7 and a rear capstan roll 7' of a net making machine.

The rope 6 is generally constructed by twisting three strands 2.

Therefore, a strand coil 1 with a strand 2 wound thereon is set on each of the three strand bobbins 3 shown on the left side of the net making machine in FIG. 2 as shown in FIG. By pulling out the strands 2, guiding the three strands 2 through the outer periphery of the cylinder 4 to the pitch voice 5 as shown in FIG. 3, and rotating the cylinder 4, the three strands 2 are
is made into one rope 6 with 50 pitch voices.

Here, pitch voice 5 refers to rope 6 as shown in Figure 6.
It has an internal shape that matches the shape of , and functions to twist three rotating strands 2 into one rope 6.

Note that by rotating the cylinder 4, twisting occurs in the opposite direction, that is, to the left in Figure 1, but this can be offset by twisting the strands 2 in the opposite direction in advance. .

The rope 6 thus made from the three strands 2 is wound around the front capstan roll 7 several times and then guided into the steam heating tube 9 through the guide section 8.

Here, the guide part 8 must be able to prevent leakage of the steam 10 inside the steam heating tube 4 as much as possible, and must be able to be used without damaging the guided rope 6.

Examples that meet such conditions include a labyrinth 12 as shown in FIG. 5, a pitch voice 5 as shown in FIG. 6, and a cylinder 20 as shown in FIG.

Note that FIGS. 1 and 2 show the case where a cylinder 20 is used as the guide portion 8. In FIG.

As shown in FIG. 5, the labyrinth 12 seals the steam 10 with a large number of constrictions 13 provided inside the cylinder.

In the case of FIG. 5, three labyrinths 12 connected by felt packings 16 are used to seal the steam 10 inside the steam heating tube 9 on the right side, and the leaked steam 10 is transferred to the exhaust pipe 15 on the left side. It's more exhausting.

In addition, when sealing the steam 10 using the labyrinth 12, the nozzle 14 is attached to the labyrinth 12 as shown in FIG.
The sealing effect of the steam 10 may be enhanced by inserting it between the nozzles 14 and injecting high-pressure air in the direction of the steam heating tube 9.

The advantage of using the labyrinth 12 is that it has an excellent sealing effect, and the disadvantage is that it is expensive, so it takes a lot of effort to prepare labyrinths of various sizes to match the diameter of the rope 6 to be manufactured. This means that it requires a financial burden.

As mentioned above, the pitch voice 5 has an internal shape that matches the shape of the rope 6, so it guides it.

When used as part 8, leakage of steam 10 can be almost completely prevented.

However, when using the pitch voice 5, it is necessary to rotate the pitch voice 5 as the rope 6 advances. Therefore, when the pitch voice is installed as the guide section 8, as shown in FIG. It must be installed via the rotary joint 17, and this installation is generally more difficult than installing the labyrinth 12.

(The rotary joint is preferably rotated by a torque motor 21, as shown in FIG. 9.

As is clear from FIG. 8, the cylinder 20 has a simple structure and is easy to install, but it is not suitable for manufacturing ropes 6 with large diameters because it has a large gap with the lower end and steam can easily escape. do not have.

Note that in the case of the cylinder 20 as well, the sealing effect of the steam 10 can be enhanced by providing a nozzle 14 in the middle of the cylinder and pressurizing high-pressure air as in the case of the labyrinth 12.

Which of the above guide parts to use as the guide part 8 must be decided by comparing and considering the merits and demerits of each of the above-mentioned parts.

Now, the rope 6 guided from the guide part 8 into the steam heating tube 9 in this manner is subjected to heat treatment by the steam 10 while traveling inside the steam heating tube 9.

The time required for heat treatment is the time required for sufficient heat to be transmitted to the center of the rope 6, and this is influenced by the diameter of the rope 6 and the temperature of the steam.

For example, when a rope 6 with a diameter of about 2 cm is heat treated with saturated steam 10 of 1 kg/crl, at least 60
A time of about seconds is required.

Since heat treatment requires a relatively long time, the traveling speed of the rope 6 is slowed down and the steam heating tube 9 is
It is preferable to make the rope 6 reciprocate several times using the guide roll 11 inside the steam 10 to increase the time that the rope 6 is exposed to the steam 10.

As the steam 10 used for the heat treatment, saturated steam or heated steam may be used.

Heating steam has the advantage that there is less steam leakage because a high temperature can be obtained at a relatively low pressure.

Rope 6 thus heat treated by steam 10
The rope 6 is guided out from the guide section 8' on the right side shown in FIGS. 1 and 2, and is wound around the rear capstan roll 7' several times to evaporate the attached moisture by the residual heat of the rope 6 itself. After that, it is led out of the net making machine as a product.

Here, the rotational speed of the rear capstan roll 7' is preferably set somewhat slower than the rotational speed of the front capstan roll 7, taking into account the shrinkage of the rope 6 due to heat treatment.

Next, the case where the rope is heat-treated using the hydraulic container 9' will be explained.

FIG. 4 shows the principle of heat treatment of the rope 6 using the hydraulic vessel 9'.

In the case of using the hydraulic container 9', the steps up to twisting the three strands 2 and forming one rope 6 are the same as in the case of using the steam heating tube 9 described above.

As shown in Fig. 4, the rope 6 that has been made is attached to the left hydraulic base 2.
After being guided through the water 23 by guide rolls 11' inside the hydraulic container 9', the guide rolls 11 inside the hydraulic container 9' guide the water into the water 23.
is exposed to steam 10 inside and subjected to heat treatment.

In this case, as is clear from FIG. 4, leakage of the steam 10 is completely prevented by the water 23 inside the hydraulic base 22.

The height of the water surface 24 inside the hydraulic container 9' is determined by the balance between the pressure of the steam 10 and the pressure of the water 23.

Therefore, since the pressure of the steam 10 rises and falls as the pressure of the steam 10 fluctuates, for safety reasons, it is desirable to set the height of the water surface 24 to a height of about 1 m above the lower part of the hydraulic container 9'.

The rope 6 that has been heat treated in this way is guided through the water 23 inside the right hydraulic base 22' and led to the outside, and the subsequent process is the same as in the case using the steam heating tube 9 described above. be.

Further, the time required for the heat treatment is also the same as in the case using the steam heating tube 9 described above.

In the manner described above, the polyolefin rope 6 is heat-treated and the rope 6 is manufactured.

The advantages of this manufacturing method are that steam 10 is used for heat treatment, so any temperature can be set with the same device by changing the steam pressure, heat treatment can be performed at high temperatures, and unlike high-frequency heating, materials with no dielectric loss are used. In addition, the pressure of the steam 10 is uniform within the container, the heat exchange efficiency is high, and even heat treatment can be performed even if there is a heat treatment.

[Brief explanation of the drawing]

Figure 1 is a plan view of the net making machine, Figure 2 is a front view of the net making machine, Figure 3 is a side view showing how the strand set on the bobbin is guided from the outer periphery of the cylinder to the pitch voice, and Figure 4 The figure is a side view showing heat treatment using a hydraulic container.
The figure is a cross-sectional view of the labyrinth, Figure 6 is a cross-sectional view of the pitch voice, Figure 7 is a cross-sectional view of the pitch voice incorporated into the rotary joint, Figure 8 is a perspective view of the cylinder, and Figure 9 is the pitch voice. A plan view of a rotary joint incorporating a steam heating tube. Explanation of symbols in the figure: 1...Strand coil;
2...Strand, 3...Strand bobbin, 4...Cylinder, 5...Pitch voice, 6...Rope, 7... ...Front capstan roll, 7'...Rear °
Capstan roll, 8... Guide section, 8 <...
... Guide section, 9 ... Steam heating tube, 10.
...Steam, 11...Guide roll, 11
'-... Guide roll, 12... Labyrinth, 13... Throttle part, 14... Nozzle, 15... Exhaust pipe, 16... ...Felt packing, 17...Rotary joint,
18...Gasket), 19...Oil seal, 20...Cylinder, 21...Torque motor, 9/...Hydraulic type % type %

Claims (1)

[Claims] 1. Production of a polyolefin rope, which is characterized by forming a polyolefin strand into a rope, and then heat-treating the rope by passing it through steam while keeping it under tension to the extent that it does not loosen. Method. 2. The tension is such that the rope is wrapped several times around the front capstan roll, then guided into the steam, passed through the steam, and then wrapped around the rear capstan roll several times.
2. The method for producing a polyolefin rope according to claim 1, wherein the rope is maintained by tension.