JPH11350293A - Net - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a net resistant to shock of heavy material, etc., by using a thermoplastic synthetic fiber having respectively specific single fiber fineness, strength and elongation and setting the mesh size of the net within a specific range. SOLUTION: A knotless net or a raschel net is knit with a polyester or polyamide thermoplastic synthetic fiber having a total fineness of >=550 dtex, a single fiber fineness of <=3.5 dtex, preferably <=3.0 dtex, a strength of >=6.0 CN/dtex and an elongation of 15-40% to obtain a net having a mesh size of 10-200 mm, preferably 15-50 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to coating and packaging materials for various types of civil engineering and construction, agriculture, forestry and fisheries, and transportation.
It can be used for filter materials and reinforcing materials. More specifically, the present invention relates to a net used as a snow protection net, a rock fall prevention net, a safety net, a curing net, a slope protection net, a seawall suction prevention net made of thermoplastic synthetic fiber, and particularly, for example, for dropping stones and earth and sand or heavy machinery. It relates to a net that is resistant to the impact of heavy objects such as trampling.

[0002]

2. Description of the Related Art Conventionally, for example, in a landfill work for constructing a breakwater, a net for civil engineering is laid to prevent outflow of stones and earth and sand. Such conventional nets made of synthetic fibers such as polyester or polypropylene are apt to be torn due to dropping of stones during construction or crushing of heavy equipment or the like, and cannot sufficiently fulfill the role of the original filter.

For example, there is a construction method in which stones are stuffed into a net and used as a reinforcing material for the purpose of embankment of a dike or prevention of scouring of a pier. There was a problem of tearing.

In order to solve these problems, wire nets and the like have been used. However, wire mesh has high rigidity and requires labor for transportation, and it is difficult to adjust to the shape of the ground or stones, so stress concentrates locally on the parts that are in contact with them and easily breaks, and rust near water places The strength is significantly reduced. Further, the wire mesh has a high rigidity and a heavy weight, so that there is a problem in workability.

When synthetic fibers are used, nets are used in which the amount of yarn used is increased so as not to be easily broken, or grids are formed by coating a resin such as polyvinyl chloride. Since the amount of resin increases, problems such as deterioration of workability and increase in cost due to increase in weight cannot be avoided.

[0006]

SUMMARY OF THE INVENTION The present invention is based on the background of the prior art, and is characterized by the fact that, for example, when a breakwater is dropped, earth and sand are less likely to be torn or ruptured by a resin coating. It is an object of the present invention to provide a net which can be realized without using the coating resin or by reducing the amount of the coating resin, or exhibiting satisfactory characteristics even with a small amount of yarn.

[0007]

SUMMARY OF THE INVENTION The present invention mainly has the following constitution in order to solve the above-mentioned problems. That is, the net is made of a thermoplastic synthetic fiber having a single fiber fineness of 3.5 dtex or less.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS If the net of the present invention is used, for example, in the construction of a breakwater, it is difficult to cause tears and breaks even when the earth and sand falls, and it is possible to prevent the outflow of earth and sand, stones, etc. due to the tear. it can. For example, in the case of using a method of packing stones in a net and using it as a reinforcing material for the purpose of embankment protection of a dike or prevention of scouring of piers, it will be broken by stones input, earth and sand or rocks flowing from the upstream And the maintenance and management of the equipment becomes easier. Further, the net of the present invention can be used with or without a coating material, so that it is excellent in lightness and flexibility, and therefore, has good workability.

Hereinafter, the present invention will be described in detail.

[0010] The net of the present invention is a net, and a known mesh such as a rhombus, a turtle-shape, and a square may be used, and the net may not be equilateral. Netting types also include knotted nets, knotless nets, Russell nets, braided nets, woven nets, etc., but meshes where nodal points do not become knots do not concentrate stress applied from soil, stone, etc. A knotless net or a Russell net that does not form a knot is preferable because it becomes difficult.

In the present invention, “mesh” means a value indicating the length of one mesh in mm. The mesh size of the net of the present invention varies depending on the purpose of use, but is preferably 10 mm or more and 200 mm or less, more preferably 15 mm or more and 50 mm or less. One eyesight
By setting the thickness to 0 mm or more, fine sand is not clogged, the filter function can be effectively performed, and the cost can be reduced. Also, by setting the mesh size to 200 mm or less, the desired object can be reliably captured by the net, and the impact compression property can be improved because the fineness of the yarn to be used is not unnecessarily increased. it can.

Further, the net of the present invention does not need to be constituted only by netting. For example, the structure may be minimally coated with a resin such as vinyl chloride, ethylene-vinyl alcohol (EVA), or polyurethane, and may be a structure within a range that does not hinder workability.

The single-filament fineness of the thermoplastic synthetic fiber constituting the net of the present invention must be 3.5 dtex or less, and preferably 3.0 dtex or less. If the single fiber fineness exceeds 3.5 dtex, sufficient impact compression resistance cannot be exhibited.

The reason why the impact compression resistance is improved when the single fiber fineness is small is considered as follows. That is, when a yarn having a small single fiber fineness is crushed by a stone or the like, the crushing pressure is easily dispersed because the cross section of the yarn is rapidly deformed. In addition, since the surface area between single yarns is large, the energy of compression deformation is easily converted to frictional heat, and the generated heat is easily dissipated without being stored in the single fibers.

The strength of the thermoplastic synthetic fiber constituting the net of the present invention is preferably 6.0 cN / dtex or more. By increasing the strength to more than 6.0 cN / dtex, the tensile strength and tear strength of the net can be further increased, the compression impact characteristics can be improved, the net can be reduced in weight, and the workability can be improved. it can.

The elongation of the thermoplastic synthetic fiber constituting the net of the present invention is preferably 15% or more and 40% or less. When the elongation is 15% or more, when a heavy object such as a stone hits the yarn, the deformation of the yarn can be increased to some extent, and the compressive stress is less likely to be concentrated on a local portion, so that the yarn is hardly broken. On the other hand, by setting the elongation to 40% or less, sufficient strength as a net can be obtained, which contributes to weight reduction.

Further, it is preferable that the total fineness of the thermoplastic synthetic fiber constituting the net of the present invention is 550 dtex or more. When the total fineness is 550 dtex or more, the tensile strength and tear strength of the net are sufficient, and the compression impact characteristics are accordingly increased. There is no particular upper limit on the total fineness, and fibers having a large fineness may be used as long as the workability is not adversely affected.

The fiber constituting the net of the present invention is a thermoplastic synthetic fiber from the viewpoint of easily obtaining mechanical properties as described above, reducing the fineness of a single fiber, and economically, and is a polyester-based fiber. Fiber, polyamide fiber, polyphenylene sulfide fiber, polyethylene fiber,
It is at least one selected from polypropylene fibers and the like, and polyester fibers or polyamide fibers are preferable in terms of light resistance, heat resistance, strength and the like. As the polyester fiber, polyethylene terephthalate, polybutylene terephthalate, polyethylene 2,6-naphthalate, polycyclohexane dimethylene terephthalate,
Fibers composed of polycaprolactone, polylactic acid, polybutylene succinate and the like are preferred. Among these, polyethylene terephthalate is particularly preferred in terms of price and light resistance. Part of the dicarboxylic acid component of these polyesters is isophthalic acid, 2,6-naphthalenedicarboxylic acid,
1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, dimer acid, sulfonic acid metal salt-substituted isophthalic acid, trimellitic acid, trimesic acid, etc. may be replaced. It can be replaced with 1,4-cyclohexanediol, an ethylene oxide adduct of bisphenol A, or the like. As the polyamide fibers, fibers composed of polycapramid, polyhexamethylene adipamide, polytetramethylene adipamide, polyhexamethylene sebacamide, polydodecamide and the like are preferable.

Further, when used outdoors or near waters such as rivers and seas, polyester fibers having excellent light resistance and little decrease in water strength are particularly preferred.

The thermoplastic synthetic fibers of the present invention may be those obtained by ordinary melt spinning. That is, the thermoplastic polymer is melted by, for example, an extruder or a pressure melter type spinning machine, measured by a metering pump, filtered in a spin pack, or the like, and then discharged from a spinneret. The discharged yarn is cooled and solidified by a cooling air or the like, applied with an oil agent, taken off, and then drawn. Even if a two-step method of winding once before stretching is used,
Either of the direct spinning and drawing methods in which the drawing is carried out without winding after spinning may be used, but the direct spinning and drawing method is preferred from the viewpoint of productivity. The take-up speed is preferably 4000 m / min or less from the viewpoint of fiber strength and 300 m / min or more from the viewpoint of productivity. The draw ratio changes depending on the take-up speed, and may be adjusted so that the elongation of the obtained fiber is in the above-mentioned range. Further, immediately after spinning and before cooling and solidification, a heating zone is preferably provided to heat the yarn to a temperature equal to or higher than the melting point of the polymer to increase the fiber strength. The stretching may be one-stage stretching or multi-stage stretching of two or more stages.
Step stretching is preferred, and heat treatment is preferably performed at a temperature about 20 to 80 ° C. lower than the melting point of the polymer before winding, and 1 to 20% relaxation treatment is preferably performed from the viewpoint of dimensional stability. .

The net strength of the net varies depending on the construction site and application, but is, for example, 25 kgf or more, and preferably 30 kgf or more when used for preventing breakwaters or embankments from being sucked out. If the weight is less than 25 kgf, tears are likely to occur due to impact or concentrated stress due to wave force or landfill sand.
Such a net strength can be efficiently obtained by increasing the strength of the thermoplastic synthetic fibers constituting the woven fabric or increasing the weaving density, but for the purpose of reducing the weight of the net, as described above. It is preferable to use a high-strength raw yarn.

Hereinafter, the features of the present invention will be described specifically with reference to examples.

[0023]

EXAMPLE A measuring method in this example is described below.

(A) Fiber strength and elongation A sample was taken in a temperature controlled room at a temperature of 20 ° C. and a humidity of 65% using a Tensilon tensile tester, with a yarn length of 25 cm and a tensile speed of 30 cm /.
Measured in minutes.

(B) Net Mesh Strength and Degree of Elongation The sample shown in FIG. 3 prepared as shown in FIG. 2 was subjected to a constant-speed elongation type tensile tester in a room at a temperature of 20 ° C. and a humidity of 65%. A tensile test is performed in the direction of the arrow at a tensile speed of 20 cm / min. FIG. 2 shows a method for sampling a tensile test sample from a net, and FIG. 3 shows a situation where the sample is attached to a tensile tester and strength is measured in the direction of the arrow.

(C) Light Resistance Test According to the provisions of JIS L 0842, light irradiation (63 ° C. × 500 hours of light irradiation) was performed using a carbon fade meter, and the strength after irradiation was measured to determine the strength retention.

Regarding the strength in water, the strength was measured by immersion in water at 20 ° C. for 24 hours, and the strength retention was determined.

Example 1 The yarn constituting the net had a tensile strength of 6.2 cN / d.
A polyethylene terephthalate filament having a single fiber fineness of 2.0 dtex having a tex of 35% and an elongation of 35% and a total fineness of 1500 dtex was used. Eight of these are combined into a mesh thread,
A Russell net having a side of 25 mm was produced. Table 1 shows the use of yarn and Table 2 shows the characteristics of the woven net.

[0029]

[Table 1]

[Table 2] Example 2 Tensile strength: 8.0 cN / dtex, elongation at break: 17
% Polyethylene terephthalate filament having a single fiber fineness of 2.0 dtex was used. Table 1 shows the use of yarn, and Table 2 shows the properties of the woven net.

Example 3 Tensile strength: 6.2 cN / dtex, elongation at break: 35
%, A single fiber fineness of 3.4 dtex was used as the polyethylene terephthalate filament. Table 1 shows the use of yarn, and Table 2 shows the properties of the woven net.

Example 4 Tensile strength: 7.0 cN / dtex, elongation at break: 35
%, A single fiber fineness of 2.0 dtex polyhexamethylene adipamide filament was used. Table 1 shows the use of yarn, and Table 2 shows the properties of the woven net.

Comparative Example 1 Tensile strength: 6.2 cN / dtex, elongation at break: 35
%, A polyethylene terephthalate filament having a single fiber fineness of 4.0 dtex was used. Table 1 shows the use of yarn, and Table 2 shows the properties of the woven net.

Example 5 Tensile strength: 8.0 cN / dtex, elongation at break: 12
% Polyethylene terephthalate filament having a single fiber fineness of 2.0 dtex was used. Table 1 shows the use of yarn, and Table 2 shows the properties of the woven net.

Example 6 Tensile strength: 5.0 cN / dtex, elongation at break: 45
% Polyethylene terephthalate filament having a single fiber fineness of 2.0 dtex was used. Table 1 shows the use of yarn, and Table 2 shows the properties of the woven net.

Test Examples In order to demonstrate the effects of the present invention, the following impact tests were performed on the above Examples and Comparative Examples. FIG. 1 shows a schematic side view of this impact test situation.

The nets of Examples 1 to 3 and Comparative Examples 1 to 3 each having a length of 2 m were laid on the concrete ground. Next, from a height of 1.5 m above the alley ground, a diameter of 5 to 10
cm stone was dropped on the center of the net. After such an impact test, the stone was carefully removed and the center 60c
m squares were cut into strips measuring 15 cm long and 7.5 cm wide. The net strength was measured for the 32 test pieces taken out in this way, and the tensile strength after the impact test and the strength retention after the impact test were calculated by comparing the tensile strength with the test piece before the impact test. The results are shown in Table 2. According to Table 2, each net of Examples 1 to 6 has a high strength retention of 70% or more after the impact test.

[0037]

According to the present invention, it is possible to obtain a lightweight net which is less likely to be torn even by falling of earth and sand at the time of construction of a breakwater and which has excellent workability.

[Brief description of the drawings]

FIG. 1 is a schematic side view of an impact test situation.

FIG. 2 is a plan view showing a method of sampling a tensile test sample from a net.

FIG. 3 is a side view showing a situation where strength is measured in the direction of an arrow by a tensile tester.

Claims (5)

[Claims] 1. A net comprising a thermoplastic synthetic fiber having a single fiber fineness of 3.5 dtex or less. 2. The net according to claim 1, wherein the single fiber fineness is 3.0 dtex or less. 3. The thermoplastic synthetic fiber has a strength of 6.0 cN /
3. The net according to claim 1, wherein the dtex is not less than dtex and the elongation is not less than 15% and not more than 40%. 4. The net according to claim 1, wherein the thermoplastic synthetic fiber is a polyester fiber or a polyamide fiber. 5. The net according to claim 1, wherein the mesh size is 10 mm or more and 200 mm or less.