JPH0784732B2 - Drain material for civil engineering - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Purpose of the invention Industrial field of application The present invention relates to a drainage material used for civil engineering, that is, a flat plate that is embedded in the soil mainly vertically to improve the soft ground. The present invention relates to a drainage material for civil engineering, which is a material in the form of a soil, which separates only the water in the soil and sucks it up to the ground surface for drainage.

Conventional technology and its problems Conventionally, as a typical drainage material for civil engineering, there is a hard type product made by laminating non-woven fabrics on both sides of a plastic core. In addition, as seen in JP-B-58-3090 and JP-B-58-29372, a heat-fusible powder was used as the adhesive.

However, there is a big problem that the process necessary for uniformly dispersing the adhesive powder on the non-woven fabric, that is, the powder processing process is considerably complicated, the equipment cost is increased, and the product cost is increased. Is there.

Further, in the conventional means using the adhesive powder, the core itself needs to be softened at the time of bonding in order to obtain the adhesive force, which limits the resin that can be used for the core. It has the drawback that it is difficult to choose a product with a high degree of activity.

In addition, the adhesive powder has a drawback that it tends to be formed into a film when melted and reduces the water permeability of the nonwoven fabric.

The present invention has been made for the purpose of solving the above-mentioned problems, and is a cost-effective method because it does not require powder treatment because it is a reasonably bonded core body and nonwoven fabric. It is an object of the present invention to provide a drainage material for civil engineering in which the water permeability of a non-woven fabric is not reduced at all and a resin having a pressure resistance can be arbitrarily selected as a resin for the core body.

(B) Structure and action of the invention The inventors of the present invention have conducted extensive studies to obtain a means for bonding a nonwoven fabric and a core without using an adhesive powder, and as a result, heat-bonding adhesiveness on both the front and back surfaces of the core itself. It was found that if layers were provided, a very good drainage material for civil engineering could be obtained.

Means for Solving the Problems The constitution of the present invention is a drain material in which a nonwoven fabric is adhered to both surfaces of a core body in which uneven grooves are formed on the entire surface, and the core body is heat-fusing adhesive to both surfaces thereof. A drainage material for civil engineering, comprising a layer, wherein the bonding is obtained by heat fusion of the adhesive layer.

FIG. 1 is an enlarged cross-sectional view of one embodiment of the drain material of the present invention.

As shown in this figure, the present invention is one in which the nonwoven fabric (2) is laminated on both surfaces of the core body (1), and this lamination is performed on both surfaces of the core body (1) by heat fusion. That is, it is obtained by heat fusion of the adhesive bond layer (3).

The core body (1) according to the present invention is one in which concavo-convex groove grooves (s) having, for example, a U-shaped cross section as shown in FIG. The heat-fusible adhesive layer (3) is provided on the entire front and back surfaces of the core body (1) along the uneven groove (s).

The depth and width of the uneven groove (s) of the core body (1) are preferably about 1 to 4 mm.

For example, the core body (1) may be made of polypropylene, and the heat-fusible adhesive layer (3) may be made of low density polyethylene or ethylene / vinyl acetate copolymer resin. The core body (1) is covered with a heat-fusible adhesive layer (3) having a softening point lower by -50 ° C.

As the manufacturing method, for example, a three-layer extruded sheet in which the resin of the core body (1) is sandwiched between the resins of the heat-fusible adhesive layer (3) is prepared, and then the uneven groove (s) is formed on the sheet. It is only necessary to perform a shaping process for forming the.

FIG. 2 illustrates this manufacturing means, and is a sectional view showing how the core body is made of a three-layer extruded sheet.

The three-layer extruded sheet (a) in this figure can be easily obtained by the conventional multi-layer sheet extruding technique, and this can be applied to the core body (1) having the concave and convex groove (s) on the entire surface. is there.

The non-woven fabric (2) is added to both surfaces of the core body (1) having the heat-fusible adhesive layers (3) on both surfaces thus obtained,
When the adhesive layer (3) is passed between rolls heated to a temperature at which it softens and melts, the nonwoven fabric (2) becomes an adhesive layer (3).
Thus, the drain material of the present invention as shown in FIG. 1 is obtained by bonding it to the core body (1).

Examples of the nonwoven fabric (2) in the present invention include a fabric weight of 30 to
70 g / m ² and a thickness of 0.1 to 0.5 mm are preferable, and this non-woven fabric (2) acts as a filter for separating earth and sand and passing only water.

The thickness of the heat-fusible adhesive layers (3) formed on both surfaces of the core body (1) described above is about 0.01 to 0.1 mm, and
The thickness of the core body (1) itself sandwiched between these is 0.2 to 1.0
The mm range is preferable, and it is sufficient to form the uneven groove (s) having the depth and width as described above.

Action In the drain material of the present invention, the non-woven fabric (2) covering the concave portion of the core body (1) through which water passes does not have any powder or coating for adhesion, and the non-woven fabric (2) is made of the adhesive. The non-woven fabric (2) adhered to the convex portions of the core body (1) is strongly adhered to the entire surface by the adhesive layer (3) without any impediment to its water permeability due to film formation or the like. The strength is very good.

In addition, since the core body (1) itself is not directly bonded to the nonwoven fabric, there is no restriction on the material of the core body (1) such as the softening point, and a material having sufficiently high pressure resistance can be selected, and the durability of the drain material is improved. It is possible to greatly improve the property.

Further, since no powder adhesive is used, complicated powder treatment is not required, and the three-layer extruded sheet can be easily produced, which is extremely advantageous in terms of production efficiency and cost.

Example 0.05 mm thick on both sides of a 0.4 mm thick polypropylene sheet
The three-layer extruded sheet having the low-density polyethylene film of was produced by the extrusion molding technique. This three-layer extruded sheet was subjected to a shaping treatment so that grooves each having a depth and a width of 2 mm were alternately formed on both surfaces, to prepare a plastic core having concave and convex grooves on the entire surface.

Both sides of this plastic core have a basis weight of 60 g / m ² , thickness of 0.15 mm
The spunbonded non-woven fabric made of polyester fiber was added and passed through a pair of steel rolls heated to 170 ° C. to melt the low-density polyethylene on the surface of the core body, and the nonwoven fabric and the core body were bonded and integrated.

Comparative Example The same non-woven fabric as in Example was sprayed with a low-density polyethylene powder that passed through a mesh of 60 mesh at a rate of 20 g / m ² , and was passed through a heating roll at 130 ° C. to adhere the powder to the non-woven fabric. . In this case, the powder was melted and pressure-bonded to form a film, and the nonwoven fabric was in a closed state.

This powder-treated nonwoven fabric was bonded and integrated in the same manner as in Example 1 by adding the powder side to both surfaces of the same core body as in Example 1.

A comparative experiment was conducted on the hydraulic conductivity and the clogging property of the above-mentioned Examples and Comparative Examples.

As a result, the hydraulic conductivity of the comparative example (similarly, the hydraulic conductivity in the direction perpendicular to the nonwoven fabric surface) was about the same as the hydraulic conductivity of the embodiment (however, the hydraulic conductivity in the direction perpendicular to the nonwoven fabric surface).
It was down 20%.

In addition, a certain amount of JIS-1, 7 and 8 test particles according to JIS-Z8901 was dispersed in water, poured into the upper part of the nonwoven fabric, and the weight of the remaining particles was measured. When the maximum diameter of the permeation particles was determined by looking at the results on a distribution chart, no difference was found in any of the nonwoven fabrics.

This fact proves that the size of the film portion formed by film formation of the powder in the comparative example is sufficiently larger than the pores formed by the fiber constitution of the nonwoven fabric. That is, it is judged that the film formation of the powder does not have the effect of reducing the pores, that is, the effect of improving the clogging property, but only acts on the reduction of the water permeation area and exerts only the adverse effect of the water permeation reduction.

C. Effect of the Invention The present invention is as described above, and does not require complicated powder treatment, and a three-layer extruded sheet is formed by a multilayer sheet extrusion technique, and the sheet is shaped into a core body of uneven grooves to form a nonwoven fabric. Therefore, the drain material manufacturing process is considerably simplified, which is very advantageous in improving efficiency and cost.

Further, since the drain material of the present invention is not a non-woven fabric subjected to an adhesive treatment, the water permeability of the non-woven fabric is not impaired at all, extremely efficient drainage is obtained, and the non-woven fabric is firmly adhered by the adhesive layer. Therefore, no trouble such as peeling occurs.

Furthermore, the material of the core body does not need to consider the direct adhesive force with the non-woven fabric, and a resin with pressure resistance can be selected, so it is possible to use a drain material with high pressure resistance, and it has excellent strength and durability. Is obtained.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of one embodiment of the drain material of the present invention. FIG. 2 is a diagram showing a manufacturing method of the core body in the present invention, and is a sectional view showing a state in which the core body is made of a three-layer extruded sheet. (1) ... core, (2) ... non-woven fabric, (3) ... heat-fusible adhesive layer, (s) ... uneven groove, (a) ... three-layer extruded sheet

Claims (1)

[Claims] 1. A drain material comprising a core body having concavo-convex grooves formed on the entire surface and a non-woven fabric bonded to both sides of the core body, wherein the core body has heat-fusible adhesive layers on both surfaces. The drainage material for civil engineering, wherein the above-mentioned pasting is obtained by heat-sealing.