JPS63256762A - Production of reticulated mat - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is applicable to, for example, cushioning materials, filter mats, plant growth mats, fish and shellfish breeding mats, reinforcement materials for civil engineering works, slope greening protection mats, etc. The present invention relates to a method for manufacturing a reticulated mat used as a reticulated mat.

(Prior Art) Various methods have been proposed for producing this type of mat.

For example, Japanese Patent Publication No. 58-9186 discloses that a large number of spinnerets with diameters of 0.2 or more are installed above a rotating roll, rotating drum, or belt conveyor with truncated cone-shaped protruding pull fills on the surface. a nozzle having 2~
The rotary rolls are placed at a distance of 30 cII, and the rotating rolls are set at an amplitude of 3 to 10 m and a frequency of 80 m in the direction of rotation. ~
Discloses a method for producing a three-dimensional network formed of continuous monofilaments by transversely vibrating at 300 times/min and spinning a thermoplastic synthetic resin melt from the nozzle onto the surface of the rotating roll, etc. (1st
conventional example).

Furthermore, for example, in Japanese Patent Application Laid-open No. 57-171749 and Japanese Patent Application Laid-open No. 58-31155, two
A large number of filaments are spun onto a rotating drum of books,
After forming a web consisting of continuous filaments on each of these rotating drums, a rope-shaped mat is produced by overlapping these two webs at the point where they are closest to each other (the point where the two rotating drums are close). A method is disclosed (second conventional example).

Furthermore, for example, Japanese Patent Publication No. 50-39185, Japanese Unexamined Patent Publication No. 50-25869, or Japanese Patent Publication No. 52-14
Publication No. 347 and the like discloses a method for manufacturing a net-like cloak 9 in which a conveyor and a winding method are devised (third conventional example).

(Problems to be Solved by the Invention) However, in the first conventional example, it is true that the strength in the lateral direction (hereinafter referred to as lateral strength) with respect to the rotation direction of the rotating roll etc. (filament extrusion direction) is excellent. However, there is a certain limit to its lateral strength, and for example, if the weight per unit area of the network formation decreases, there is a problem that the strength improvement will not be as expected. Ta.

In addition, in the second conventional example, the transverse strength of the obtained web is extremely low compared to the strength in the longitudinal direction (longitudinal direction of the web), and moreover, only webs with high density and low porosity can be manufactured. There were problems such as.

Furthermore, in the third conventional example, when trying to obtain the transverse strength of the reticulated mat, there was a problem that the weight of the mat increased or the density increased and the porosity decreased.

Mats with low porosity as mentioned above, that is, dense mats, do not pose any problem when used as a filter cloak, for example, but when used as cushions, slope protection mats, etc. As a result, the cost increases as the weight per unit surface of the mat increases, and if the mats are clogged, soil may not be sprayed into the mat properly in construction methods that involve spraying soil.

The present invention was made in view of the above-mentioned conventional problems, and it is an object of the present invention to provide a method for manufacturing a reticulated mat that is lightweight, has a high porosity, has excellent tensile strength and compressive strength, and is inexpensive. It is something to do.

(Means for Solving the Problems) The method for producing a rope-like mat according to the present invention includes a method for producing a rope-shaped mat, in which a large number of protrusions are placed on a conveying surface at a predetermined distance downward from a nozzle in which a large number of spinning ports are arranged in parallel. The conveying body is moved in a direction perpendicular to the direction in which the spinnerets are arranged side by side and is vibrated in a direction perpendicular to the direction of movement, while the thermoplastic synthetic resin melt is transferred to the nozzle. The continuous monofilaments of the spun thermoplastic synthetic resin melt are spun out from the spinneret and are allowed to fall under their own weight and deposited on the conveying surface of the conveying body, and each monofilament deposited on the conveying surface. is heated at a temperature below the melting point of the thermoplastic synthetic resin and at least 50° C. lower than the melting point.

(Function) When the thermoplastic synthetic resin melt is extruded from each spinneret of the extruder, the extruded thermoplastic synthetic resin melt is
It becomes a continuous monofilament and falls freely. The fallen monofilaments reach the conveyance surface of a belt conveyor (conveyor) that moves around while vibrating in the direction of the parallel spinnerets, and each monofilament falls on the top of each protrusion or between each protrusion. do. At this time, since the belt conveyor is vibrated as described above, the monofilaments that have fallen onto the belt conveyor are deposited in a state in which adjacent monofilaments are well intertwined with each other due to the vibration. Then, the deposited monofilament is heated by, for example, an infrared heater to prevent the monofilament from rapidly cooling. That is, if each monofilament falls onto the conveyance surface of the belt conveyor and the conveyance surface is cold, the heat of each monofilament is taken away, and the fusing ability of the monofilament itself is reduced. Therefore, the fusion strength at the intersections between the monofilaments decreases, and the strength of the obtained molded product (reticular mat) decreases, but the heating prevents the monofilaments from rapidly cooling, and the strength at the intersections decreases. This further improves the fusion strength.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

The method of the invention is carried out using the apparatus shown in FIG. The apparatus includes a spinneret 11 for spinning a continuous monofilament of a thermoplastic synthetic resin melt.

an extruder 1 having a nozzle 12 provided with nozzles 11, . It is composed of an infrared heater 4 and an infrared heater 4.

Each spinneret 11.11 of the extrusion machine is, for example,
As shown in the example, 2
They are arranged neatly in rows. The arrangement of the spinnerets 11 is not limited to this, and may be arranged, for example, in several rows, in a houndstooth pattern, or in negative rows.

However, it is preferable that the intervals between the respective spinnerets 11 be the same, and the distance between the center points of the spinnerets 11 is preferably 2111 to 30 fl. This is because when the distance between the spinnerets 11 falls below the lower limit of the above range, the distance between the spun monofilaments 5 becomes too narrow, and the monofilaments 5 are transferred to the carrier 2.
This is because even the slightest air vibration causes them to stick together before reaching the conveying surface 22, making it difficult to reach the conveying surface 22 regularly.

Furthermore, when the distance between the spinning ports 11 exceeds the upper limit value, the distance between the monofilaments 5 becomes too wide, reducing the chance of contact between the monofilaments 5 and decreasing the strength in the lateral direction. will be invited.

The diameter of each spinneret 11 is preferably 0.2 to 2.0 fl. If it is less than the lower limit of the above range, it may cause uneven flow when the thermoplastic synthetic resin melt is spun, or Problems arise such as the pressure in the extruder 1 for melting the thermoplastic synthetic resin becoming too high. Moreover, if the diameter of the spinning orifice 11 exceeds the above-mentioned upper limit, the thickness of the monofilament 5 itself becomes thicker, resulting in an increase in the weight of the molded product.

The conveyor 2 includes, for example, a belt conveyor 21 and a pedestal 23 that supports the belt conveyor 21. The belt conveyor 21 is provided with a large number of protrusions 24 on its surface. The conveying surface (upper surface) 22 of the belt conveyor 21 extends a predetermined path fmM downward from each spinning nozzle 11 of the extruder 1, and the conveying direction is from each spinning nozzle 11.
... (the direction indicated by arrow A in the figure) is substantially perpendicular to the direction in which the ... are arranged in parallel. The frame 23 is a belt conveyor 21
are supported so as to be able to vibrate in a direction perpendicular to the conveying direction A, that is, in a direction in which the respective spinnerets 11 are arranged side by side.

In such a configuration, the belt conveyor 21 is rotated in a predetermined direction A, and is vibrated by the frame 23 in a direction perpendicular to the rotation direction A. This vibration has an amplitude of 20 to 30 degrees and a frequency of 100 to 30 degrees.
A range of 400 times/min is preferred. If these amplitudes and frequencies are below the lower limits of 20 times/min and 100 times/min, the monofilaments 5 falling from the adjacent spinning nozzles 11 will not be sufficiently intertwined with each other in the vibration direction, and forming The strength of the reticulated Matsutoro in this vibration direction is reduced. Conversely, even if the amplitude and frequency exceed the upper limits of 30 m1 and 400 times/min of the range, the strength of the formed reticulated mat in its vibration direction will hardly improve, so the upper limits are sufficient. The installation position of the belt conveyor 21 varies depending on the diameter of each spinneret 11, but the distance from the spinneret 11 to the belt conveyor 21 is preferably 3 to 30 cIl, and the distance is within the above range. If the upper limit of is exceeded, the monofilaments 5 will be cooled while freely falling, and will lose their own fusing function, causing a decrease in the strength of the molded product.

Further, the protrusions 24... have a height of 3 to 10 (lIIm
It is desirable that they are arranged at a rate of 1 x 103 to 2 x 10' pieces/d. The height of the protrusions 24... is made approximately equal to the thickness of the reticulated maturo to be molded. For example, when molding the rope-like maturo to a thickness of 50 mm, the height of the protrusions 24... Projection 2 with a height of 501m
When the height of the monofilaments 5 exceeds the upper limit of 100 m, the monofilaments 5 do not fully enter the valleys between the protrusions 24, resulting in uneven thickness of the resulting rope-shaped maturo. Further, the density of the protrusions 24... is the lower limit lX
When the number is less than 10' pieces/d, the elasticity of the obtained rope-like pine nuts decreases. On the contrary, when the density of the protrusions 24 exceeds the upper limit value 2X10' pieces/d, the protrusions 24...
The gaps between the two monofilaments 5 become smaller, and the monofilaments 5 do not fully penetrate between the protrusions 24, resulting in uneven thickness in the reticulated MAFTER. The shape of the protrusions 24 must be such that each spun monofilament 5 can be deposited on the top thereof. For example, as shown in FIG. As shown in C), the top of each protrusion 24 may have a planar structure such that the dropped monofilament 5 does not slide off the top.

The infrared heater 4 heats the monofilaments 5 deposited on the conveying surface 22 of the belt conveyor 21 at a temperature that is below the melting point of the thermoplastic synthetic resin used for manufacturing and at least 50° C. lower than the melting point. It is for heating. The heating of the monofilament 5 is as follows:
The heating means is not limited to such an infrared heater 4, and other heating means may be used. Further, instead of heating with the infrared heater 4, the belt conveyor 21 may be heated with some kind of heating means to raise its surface temperature.

Next, a method for manufacturing reticulated maturo using the apparatus as described above will be explained.

First, when a thermoplastic synthetic resin melt is extruded from each spinneret 11 of the extruder 1, the extruded thermoplastic synthetic resin melt is made up of continuous monofilaments 5...
, 5... and falls freely. The dropped monofilaments 5 are transported to the conveying surface 2 of the belt conveyor 21, which vibrates and moves around in the direction in which the spinnerets 11 are arranged side by side.
2, each monofilament 5... falls on the top of each protrusion 24 or between each protrusion 24.... At this time, since the belt conveyor 21 is vibrated as described above, the monofilaments 5 that have fallen onto the belt conveyor 21 are deposited in a state in which adjacent monofilaments 5 are well intertwined with each other due to the vibration. Then, the deposited monofilaments 5 are heated by the infrared heater 4, and rapid cooling of the monofilaments 5 is prevented.

That is, if each monofilament 5 falls onto the conveyance surface 22 of the belt conveyor 21 and the conveyance surface 22 is cold, the heat of each monofilament 5 is taken away and its own fusion is reduced. Wearing ability decreases. For this reason,
The fusion strength at the intersections of the monofilaments 5 decreases, and the strength of the obtained molded product (rope-like maturo) decreases, but as described above, by heating with the infrared heater 4, Rapid cooling of each monofilament 5 is prevented, and the fusion strength at the intersection is further improved.

As described above, a net-like maturo is produced on the belt conveyor 21 in which the monofilaments 5 are intertwined and fused together in the vibration direction and the conveyance direction. The Matsutoro is conveyed in a predetermined direction by a belt conveyor 21,
For example, it is wound up by a winding machine 7.

Examples of the thermoplastic synthetic resin used in the method of the present invention include polyolefins such as polyethylene and polypropylene, polyurethane, polyamide, polyester, polyvinyl chloride, and polycarbonate.

In the embodiment described above, the belt conveyor 21 is used as the conveyor 2, but the present invention is not limited to this, and a configuration may be adopted in which, for example, a rotating roll, a rotating drum, or the like is used.

(Effects of the Invention) As explained above, according to the manufacturing method of the present invention, it is possible to obtain a lightweight, low-cost rod-like mat that is lightweight, has a high porosity, has excellent tensile strength and compressive strength, and is low in cost. In particular, it can be used as an alternative to greening protection mats on slopes where wire mesh and the like have traditionally been used due to the need for strength, and because it is lighter than conventional wire mesh and the like, it improves workability.

(Example 1) (A) Adjustment of molded body Thermoplastic synthetic resin 6-Nylon Nozzle diameter 0.6 liters Projections Height 101 m Density 5000 pieces/M Distance between spinning spout and surface of 1 general feeding body 10 cm Amplitude 30 irises l Spun monofilament from the spinning spout under conditions of a frequency of 150 times/min or more, width 1500mm, length 30cm
A roll (mesh mat) of m was obtained.

The thickness and weight of the molded body are shown in the attached table.

(B) From the molded body prepared in performance evaluation (8) of the molded body, 150
A sample was cut so that the width was 50 mm and the width was 1 mm, and the force until it broke was measured using a tensile tester at a speed of 100 mm/min (longitudinal strength measurement).

Similarly, the length is 150Iu along the direction perpendicular to the direction of travel.
A sample was cut to have a width of 50 mm, and the same tensile test as above was conducted (transverse strength measurement).

The above evaluations were also performed for the following Examples 2 to 5 and Comparative Examples 1 to 5. The results are shown in the attached table.

<Example 2> Same as Example 1 except that the nozzle diameter was 1.8 m.

<Example 3> Example 1 except that the distance between the conveyor and the conveyor was set to 25 cm
Same as.

<Example 4> Same as Example 1 except that the height of the protrusions was 90 dragons and the density was 2000 pieces/m.

<Example 5> Same as Example 1 except that the amplitude was 20u and the frequency was 400 times/min.

<Comparative example 1> Same as Example 1 except that infrared heating was not performed.

Comparative example 2> Same as Example 1 except that the height of the protrusion was 150 fins.

Comparative Example 3 Same as Example 1 except that the density of protrusions was 25,000 pieces/d.

<Comparative Example 4> Same as Example 1 except that the distance between each spinning port and the conveyor was set to 33 cll.

Comparative example 5> Same as Example 1 except that no vibration was applied.

(Margin below)

[Brief explanation of drawings]

FIG. 1 is a schematic side view showing an example of an apparatus used in the method for producing a reticulated mat according to the present invention, and FIG. 2 +a) to
(C) is a perspective view showing each embodiment of protrusions provided on the conveying surface of the conveying body. 1... Extruder 11... Spinneret 12... Nozzle 2...
Conveying body 21... Belt conveyor 22... Conveying surface 24...
・Protrusion 4... Infrared heater 5... Monofilament 6... Net cloak Patent applicant Representative of Sekisui Chemical Co., Ltd. Hiroshi 1) Kaoru Figure 7 2 (a: Yu (b) (C)]

Claims (1)

[Claims] 1) A conveying body having a large number of protrusions on the conveying surface is placed at a position spaced a predetermined distance downward from a nozzle in which a large number of spinnerets are arranged side by side, and this conveying body is directed in the direction in which the spinnerets are arranged side by side. The thermoplastic synthetic resin melt is spun out from the spinneret of the nozzle, and the spun thermoplastic synthetic resin melt is continuous. The monofilaments are dropped by their own weight and deposited on the conveying surface of the conveying body, and each monofilament deposited on the conveying surface is heated to a temperature below the melting point of the thermoplastic synthetic resin and 50° C. above the melting point.
A method for producing a reticulated mat characterized by heating at a temperature higher than a low temperature.