JPS6256256B2 - - Google Patents

Description

[Detailed description of the invention] This invention has a structure in which thermoplastic resin filaments are intertwined with each other, and has excellent water permeability and compression resistance, and is suitable for being buried underground and used as a drainage material. The present invention relates to a method for manufacturing a bulky reticular body.

Conventionally, bulky net-like bodies are manufactured by spinning a molten thermoplastic resin through a number of nozzles installed downward in a die, and then lowering the resin as it is and immersing it in water so that it can be spun on the water surface or in the form of filaments. The thermoplastic resin filaments in the molten state are slid by being pulled at a speed slower than the above speed, and are intertwined and fused at the parts where they contact each other. A method is known in which the sliding portion is cooled and solidified using cooling water injected from a number of cylindrical nozzles provided around the sliding portion. Special Publication No. 49-45481, Special Publication Showa
No. 50-8382, Special Publication No. 39185, Special Publication No. 50-39185, Special Publication No. 51-
This is what is shown in No. 15551.

However, while the former method has the advantage of being rapidly cooled, it is also rapidly cooled during the formation of loops by sliding on the water surface, resulting in a smaller loop diameter, which means that the bulky net-like structure cannot be placed underground. The problem was that it did not have sufficient water permeability and compression resistance, which are required when it is buried and used as a drainage material.

Also, in the latter case, the loop diameter is small, and if the take-up speed is slowed down in order to increase the loop diameter to improve water permeability and compression resistance, there is a problem that the loops become dense and it is difficult to form a bulky network. Moreover, the cooling water ejected from the nozzle does not uniformly apply to the sliding parts, resulting in uneven cooling, and there are problems in that loops or avalanches occur in areas where the amount of water is small, and water permeability deteriorates.

In order to increase the loop diameter, a method of forcibly vibrating the molten wire descending from the nozzle was also proposed in Japanese Patent Publication No. 51-24012, Japanese Patent Publication No. 56-3941, and Japanese Patent Publication No. 56-3941.
No. 56-3942, both of which require complex vibration devices.

The present invention has been made with the aim of eliminating the above-mentioned drawbacks of the conventional method, and is designed to take up a molten thermoplastic synthetic resin filament at a speed slower than its descending speed, and to apply a cooling liquid to a predetermined width. The water flows down diagonally inward uniformly and hits the side surface of the filament, and the synergistic effect of these two causes the filament to slide, increasing the formed loop diameter, and uniformly cooling it to improve water permeability. A bulky reticular body with excellent compression resistance is obtained.

Embodiments of the present invention will be described below with reference to the drawings. A molten thermoplastic resin is spun from a number of nozzles 2 provided downward in a die 1, and these filaments 3
is allowed to naturally fall as it is, and the filament is sandwiched and passed between a pair of endless belts 4, 4 arranged symmetrically.

Each endless belt is driven at a speed slower than the descending speed of the above-mentioned filaments, and its upper part is bent diagonally outward from the middle part at an appropriate angle, so that the upper end of one of the belts is bent inward. A pipe 6 with a slit 5 facing downward in the axial direction is provided parallel to a pulley 7 on which the belt is hung, and the cooling water passed through the pipe 6 is jetted out from the slit 5 and is uniformly distributed along the upper side of the belt. The molten thermoplastic resin filaments 3, which are flowing down uniformly, are taken up by the belt 4 at a speed slower than the descending speed, and are also pushed by the force of the cooling water flowing down the belt. The loop is then bent and the synergistic action of the two forms a large loop. The loops that come into contact with each other are fused at the contact portion. The cooling water cools the sliding portion simultaneously with the sliding action of the filaments, and while it falls between the belts, the sliding portion is uniformly and completely cooled and solidified, resulting in a bulky net-like structure with a large loop diameter. is obtained.

If the flow rate of the cooling water is too high, the molten filaments will scatter, making it difficult to obtain a uniform bulky network, and if the flow rate is too low, the filaments will not be sufficiently bent and solidified by cooling.
The preferred flow rate varies depending on the interval between the belts, the thickness of the filaments, their density, etc. Generally, the flow rate is 3 to 6 mm1/
It is desirable to be within the cm/sec range.

Here, mm1/cm/sec is the flow rate per unit length (cm) in the direction perpendicular to the drawing (mm1/sec)
It is a unit that indicates

In FIG. 2, take-up rolls 9 are arranged on both sides instead of a belt, and one upper roll 9a is provided with a guide plate 11 inclined diagonally outward through which cooling water jetted from a slit 10 flows.

In each of the above embodiments, the cooling water flows only from one side of the sliding part, but if a thick and bulky molded product is to be obtained, the pipe with the slits is also flowed from the other side. It is desirable that the cooling water be applied from both sides to promote the formation of the loop and to cool it.

According to the method of the present invention, uniform cooling can be achieved by an extremely simple method of allowing the cooling liquid to flow down evenly and uniformly in an inclined state, and at the same time, the drawing speed of the filament can be made slower than the descending speed. Coupled with the action caused by this, it is possible to perform sliding and form a loop with a large diameter, thereby increasing the number of fused parts with other loops and obtaining a bulky molded product with good lateral connections. Can be done.

The bulky network thus obtained has superior water permeability and compression resistance compared to conventional ones, and can be used to treat spring water from the ground, such as in tunnels, fields, culverts, embankments, retaining walls, backfills, etc. It can be used as a drainage material for industrial purposes and for treating pore water existing underground.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a method for manufacturing a bulky net-like body according to the present invention, and FIG. 2 is a diagram showing another example. 1... Dice, 2... Nozzle, 3... Line, 4
...Belt, 5...Slit, 6...Pipe, 7
...pulley, 9...take-up roll, 10...slit, 11...information board.

Claims (1)

[Scope of Claims] 1. A molten thermoplastic resin filament is spun downward from several nozzles provided in a die and descends at a speed lower than the rate of descent of the filament by a feeding device provided below the nozzles. The coolant is drawn in at a high speed and uniformly jetted out from the slits provided on at least one of the left and right sides of the filament, flowing diagonally inward and hitting the side of the filament. A method for producing a bulky net-like body, which comprises sliding the strips, fusing their contact portions, and simultaneously cooling and solidifying them with the cooling liquid. 2 The feeding device is an endless belt arranged on the left and right sides of the filament, the belt is bent at the middle part so that the upper part slopes outward, and a pipe with a slit formed at the end is attached. A method for manufacturing a bulky reticulated body according to claim 1. 3. Claim 1, wherein the feeding device is a take-up roll arranged on the left and right sides of the filament, and a guide plate for attaching a pipe with a slit formed at the upper end is provided to be inclined toward the take-up roll. The method for producing the bulky reticular body described above.