JP2001323469A - Method of making for resin net for reinforcing banking - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a net made from a molecularly oriented resin, more specifically, a method of making for a resin net embedded in banking or earth on a face of slope or the like to reinforce it. SOLUTION: The method of making for the resin net for reinforcing banking comprises a first process for forming a non-drawn resin net in which a number of rhomboidal empty areas 13 are formed to point in a certain direction; a second process for heating the non-drawn resin net to a temperature at which it can be drawn; and a third process for drawing the heated non-drawn resin net in a direction Z diagonal to the empty areas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molecularly oriented resin net, and more particularly, to a method for producing a resin net buried in a soil such as an embankment or a slope to reinforce it.

[0002]

2. Description of the Related Art In recent years, when reinforcing an embankment or a slope, etc., a resin net has been buried and reinforced. Such a resin net for reinforcing the embankment has many holes formed in a resin plate. This is a resin net composed of a stretched strand portion which is stretched uniaxially or biaxially and an unstretched land portion. In particular, in uniaxial stretching, it is composed of a stretched strand portion stretched in the stretching direction and an unstretched land portion perpendicular to the stretched strand portion, and the perforated portion formed in the resin plate is an elliptical shape that is extremely long in the stretching direction. It is what makes.

However, the strength against the collapse of the embankment is determined by the cross-sectional area and the shear resistance due to the shape in the direction in which the resin net is pulled out relatively to the soil that has entered the hole of the embankment reinforcing resin net. For this reason, it is preferable that the hole portion of the resin net after the stretching is stretched substantially uniformly in the longitudinal direction and the width direction. For this reason, in addition to uniaxial stretching, biaxial stretching is also performed. In general, a method of stretching in the width direction after uniaxial stretching is performed. However, this is not very advantageous, and requires large and complicated equipment, precise control, and the fact that production is performed relatively slowly, making it unsuitable for mass production. There was a need for improvement.

[0004] In the conventional method of producing a bank for reinforcing embankment by uniaxial stretching, a large number of holes are formed in a long and flat resin plate, and the holes are heated by passing between heated metal rolls. Alternatively, it is passed through a high-temperature atmosphere and heated, and is sandwiched between a front roll and a rear roll that sandwich it,
A method is adopted in which the rotation speed of the rear roll is increased to stretch the resin plate.

[0005]

SUMMARY OF THE INVENTION The present invention provides a novel method for obtaining a resin net for embankment reinforcement equivalent to a resin net obtained by biaxial stretching using a conventional uniaxial stretching apparatus. .

[0006]

According to a first aspect of the present invention, there is provided a first step of forming a large number of unstretched resin nets with a diamond-shaped (including a square) airspace directed in a certain direction, and capable of stretching the unstretched resin nets. And a third step of stretching the heated unstretched resin net in a diagonal direction of the airspace, the method comprising the steps of:

According to a second aspect of the present invention, there is provided an unstretched resin body in which a large number of substantially regular hexagonal voids are formed in one direction by unstretched resin strands, and a pair of opposing sides has a diameter approximately twice as large as the other side. A first step of forming a net, a second step of heating the unstretched resin net to a temperature at which stretching is possible, and a third step of stretching the heated unstretched resin net with the pair of sides having the large diameter as a stretching direction. And a process for producing a resin net for embankment reinforcement comprising the steps of:

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred examples of the unstretched resin net used in the present invention include resins such as polyethylene, polypropylene and polyethylene terephthalate, which can be applied to any invention. The unstretched resin net may be obtained from a resin plate, or may be formed from an unstretched resin strand. That is, a large number of endless unstretched resin strands are pulled out (extruded) in parallel with each other.
Unstretched resin nets are obtained by pulling out the same unstretched resin strands by tilting and disposing them, and the overlapped intersections are welded and integrated with each other. In the second invention, one of the opposite sides, that is, the side parallel to the Z direction in the stretching direction has a diameter approximately twice as large as the other side, and the unstretched resin strand at that portion is welded and integrated.

Here, the first invention will be further described. As an example, the rhombus (including the square in the present invention) is stretched so that its diagonal is aligned with the stretching direction, and the stretching force is substantially from each intersection. It is a resin net for embankment reinforcement with a diamond-shaped hole that is equally spread over a pair of sides and each side is stretched almost evenly, and biaxial stretching is performed by simply expanding this. Thus, a substantially similar stretched resin net can be obtained. Of course, in the case of the first invention, the unstretched resin net may be formed by perforating a diamond-shaped hole in the resin plate, or may be formed of the unstretched resin strand as described above.

The angle of the rhombus in the stretching direction of the unstretched resin net in the first invention is about 55 to 155 degrees, preferably about 80 to 135 degrees. The thickness of the unstretched resin strand constituting the unstretched resin net is 2 to 10
mmφ, preferably 3 to 7 mmφ, and the diameter of the large diameter part in the second invention is twice as large.

Next, referring to the second invention, a large number of substantially regular hexagonal voids are formed by unstretched resin strands, and a pair of opposing sides, that is, a side parallel to the Z direction in the stretching direction is substantially the other side. By using an unstretched net having twice the large diameter, by stretching the pair of sides having the large diameter as the stretching direction, the large diameter portion is separated from the other side (small diameter), that is, from the two sides. Since the force is applied and the film is stretched, a substantially equal force is applied to all sides, and a large hole of substantially a regular hexagon is formed on each of the stretched sides. Therefore,
The resin net for reinforcing the embankment having a substantially regular hexagonal hole constituted by the stretched strand can be obtained by simply expanding this.

In the second step, it is desired that the unstretched resin net constituted by the unstretched resin strands is heated almost uniformly. For this reason, it is good to immerse in a heated liquid, for example, warm water heated to 50 ° C. or higher, preferably 80 to 95 ° C. In the second step, it is preferable to place the unstretched resin net in a temperature range suitable for molecular orientation. In the case of a highly crystalline polymer such as polyethylene or polypropylene, the point is slightly lower than the melting point.
A quasicrystalline polymer such as T is suitable in a very narrow range between the glass transition point and the softening point. In the third step, the heated unstretched resin net is passed between the front roll and the rear roll, and stretched by increasing the rotation speed of the rear roll.

[0013]

The present invention will be described in more detail with reference to the following examples. (Example 1) Unstretched strands made of polyethylene resin are extruded at intervals of 20 mm, and the strands are similarly extruded in a direction perpendicular to the extrusion direction, and are pressed from above and below to form an unstretched resin net having a square air space. did. The thickness of this strand is approximately 3.5 mmφ,
The intersection is welded and integrated. FIG. 1 is a plan view of the unstretched resin net, where 1 is an unstretched strand,
2 is an intersection, and 3 is a square airspace.

The unstretched resin net is stretched in the diagonal direction of a square. First, the resin net is immersed in warm water at 90 ° C., and then the surface is relatively soft, for example, a rubber material ( Between the pair of front rolls (diameter: 30 cm) covered with a pair of front rolls (diameter: 30 cm), and the rotation speed of the rear rolls is increased to pull the resin net between the rolls. Strands constituting an undrawn resin net are drawn and oriented. The stretching direction is either the X direction or the Y direction in FIG. At the time of stretching, the force from the roll is applied almost equally to each strand 1, so that each strand 1 is evenly stretched.

The obtained embankment reinforcing resin net is obtained by stretching each strand approximately uniformly to a length of 5 times, and is extremely strong. Then, by expanding the stretched strand into a square, a net almost identical in property to a net manufactured by biaxial stretching was obtained.

Example 2 An unstretched resin net having substantially regular hexagonal voids was produced by the same unstretched strand made of polyethylene resin as in the previous example. In each case, a strand is obtained by extrusion, and a pair of opposite sides are welded to double the thickness. FIG. 2 is a plan view of the unstretched resin net.
Reference numeral 12 denotes a strand at a portion where unstretched strands are overlapped and welded and integrated. Reference numeral 13 denotes a substantially hexagonal airspace.

The stretching step is the same as that described above, and although omitted here, the stretching direction is the Z direction in FIG. For this reason, the unstretched strand 1 is stretched by applying a double force to the unstretched strand 1 because the stretching force is distributed to the left and right and distributed uniformly to the unstretched strand 3 site. It is.

The obtained embankment-reinforcing resin net is obtained by stretching each strand substantially uniformly, has a very high strength, and expands the stretched strand (regular hexagon) to form a biaxially stretched net. A net with almost the same properties was obtained.

[0019]

The resin net for reinforcing embankment of the present invention is manufactured by a uniaxial stretching method. The obtained net has substantially the same properties and shape as the biaxially stretched net. Therefore, it became possible to manufacture it at a very low cost.

[Brief description of the drawings]

FIG. 1 is a plan view of an unstretched resin net according to the first invention.

FIG. 2 is a plan view of an unstretched resin net according to the second invention.

[Explanation of symbols]

 1 ‥ Unstretched strand, 2 ‥ intersection of unstretched strand, 3 ‥ substantially square airspace, 11 ‥ unstretched strand, 12 ‥ overlapping part of unstretched strand, 13 ‥ substantially regular hexagonal airspace, X, Y, Z ‥ stretching direction.

Claims (8)

[Claims] 1. A first step of forming an unstretched resin net formed by forming a large number of rhombic voids in a predetermined direction, a second step of heating the unstretched resin net to a temperature at which the unstretched resin net can be stretched, A third step of stretching the stretched resin net in a diagonal direction of the airspace, the method comprising the steps of: 2. An unstretched net in which a large number of substantially regular hexagonal voids are formed in one direction by unstretched resin strands, and a pair of opposing sides forms a large diameter approximately twice as large as the other sides. One step, a second step of heating the unstretched resin net to a temperature at which the unstretched resin net can be stretched, a third step of stretching the heated unstretched resin net with the pair of sides forming the large diameter as a stretching direction,
A method for producing a resin net for reinforcing embankment, comprising: 3. The method according to claim 1, wherein the unstretched resin net is selected from polyethylene, polypropylene and polyethylene terephthalate. 4. The method according to claim 1, wherein in the first step, the unstretched resin net is formed of a resin plate and a square or a rhombus is formed by press working. 5. The method according to claim 1, wherein in the first step, the unstretched resin net is made of an unstretched resin strand, and the intersection is welded. 6. The method according to claim 2, wherein the large diameter portions of the unstretched resin strands are welded to each other in the first step. 7. The method according to claim 1, wherein in the second step, the resin net is immersed in a heated liquid. 8. The embankment reinforcement according to claim 1, wherein in the third step, the heated unstretched resin net is passed between the front roll and the rear roll, and is stretched by increasing the rotation speed of the rear roll. Manufacturing method for resin net.