JPH0924565A - Pervious civil engineering sheet and method for producing the same - Google Patents

Abstract

(57) [Summary] [Object] The present invention is to provide a water-permeable civil engineering sheet excellent in cushioning property, workability, drainage property, and durability, and a method for producing the same. A water-permeable civil engineering sheet of the present invention is a laminated sheet in which a network structure sheet made of a soft thermoplastic resin filament and a fiber sheet are integrated, and the water permeability coefficient of the laminated sheet is 1 × 10 ^2. cm / sec or more, and the method for producing such a water-permeable civil engineering sheet is such that after the soft thermoplastic resin is melt-extruded to form a filament, the filament is still in a molten state. In addition, it is characterized in that it is laminated on the surface of the fiber sheet and fused.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention mainly relates to underwater structures,
The present invention relates to a water-permeable civil engineering sheet that prevents spillage and scouring on breakwaters, river levees, and the like, and also relates to a water-permeable civil engineering sheet as a protective material for a water impervious sheet for an industrial waste treatment plant, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, a woven fabric has been used as a sheet for preventing suction and scour in an underwater structure, a breakwater, a river dike, etc.
Non-woven fabric is used.

However, with these sheets, for example, when they are laid for a long time (1 to 12 months) for seawall protection work, the sheets are damaged due to the abrasion between the sheets and the stones, and the typhoon passes. In winter with a lot of waves, the sheet was damaged in a shorter period of time, and there was a problem that the sediment in the embankment flowed out from the damaged portion of the sheet.

Further, the cushioning material for the water blocking sheet for the industrial waste treatment plant has a problem that it is damaged by the impact of dropping the waste, the water blocking sheet is also damaged, and sewage flows out underground.

[0005]

SUMMARY OF THE INVENTION The present invention has been devised to solve the above-mentioned problems of the prior art, that is, it has the same features as the conventional civil engineering work sheet, but also has a cushioning property and a construction property. It is intended to provide a water-permeable civil engineering sheet excellent in durability and drainage and excellent in durability, and a method for producing the same.

[0006]

The present invention employs the following means in order to achieve such an object. That is, the water-permeable civil engineering sheet of the present invention is a laminated sheet in which a network structure sheet made of a soft thermoplastic resin filament and a fiber sheet are integrated, and the water permeability coefficient of the laminated sheet is 1 × 10 ² cm. / sec or more, also, the manufacturing method of such a water-permeable civil engineering sheet, after forming a filament by melt-extruding a soft thermoplastic resin, while the filament is still in a molten state It is characterized in that it is laminated on the surface of the fiber sheet and fused.

[0007]

In the present invention, in the conventional suction sheet and scour prevention sheet, as a result of earnestly studying a measure for preventing the problem that the sheet is damaged due to the abrasion with the stones and the earth and sand flow out from the sheet damaged portion, By combining a specific cushioning sheet and a filter sheet, it has been clarified that it is possible to provide an excellent water-permeable civil engineering sheet that solves all the conventional problems. That is, a net-like structure sheet formed of a linear body that is, so to speak, amorphous or nearly unstretched, which was formed while the soft thermoplastic resin filament was still in a molten state, was excellent in flexibility and excellent in buffer function. Focusing on the fact that the sheet has such characteristics, it has been clarified that the above-mentioned effect can be satisfactorily achieved with a sheet having a structure in which such a network structure sheet is laminated on a water-permeable fiber sheet.

The soft thermoplastic resin in the present invention is a product of JIS
Bending rigidity according to K-7106 is 15 to 10,000 kg / cm ²
And more preferably 30 to 2000 kg / cm
² , particularly preferably in the range of 50 to 1000 kg / cm ² in terms of flexibility and cushioning property. That is, when the laminated sheet of the present invention is used as, for example, a water-permeable civil engineering sheet for hydraulic engineering, when the flexural rigidity of the soft thermoplastic resin is 300 kg / cm ² or more, the flexibility of the fiber sheet as the base material The sheet made of the resin filament cannot follow, and the concentration of wave energy occurs on the resin filament sheet, which leads to cracks and breaks.
On the other hand, when it is 30 kg / cm ² or less, there is a problem that there is no resin that can be adopted in terms of practical strength.

Examples of the soft thermoplastic resin satisfying the flexural rigidity condition include soft polyvinyl chloride and EV.
It is possible to use, but not limited to, those using A or EVA as a modifier.

The flexibility of the molded sheet made of the soft thermoplastic resin filament itself is preferably 20000 mg or less in terms of Gurley stiffness. This is because the civil engineering sheet is usually transported and constructed in a roll form, and when the Gurley stiffness of the soft thermoplastic resin filament sheet is 20000 mg or more, the handling property of the laminated sheet is significantly deteriorated. .

Further, such a soft thermoplastic resin filament sheet needs to have water-permeable voids to such an extent that the water permeability of the fibrous sheet as a base material is not impaired when laminated. That is, the shape of the net-like structure sheet made of the soft thermoplastic resin filaments is, for example, a large number of linear or band-like filaments, a mesh formed by arranging the filaments in a lattice form as well as a three-dimensional net-like structure. It is possible to use a sheet-like sheet, and further, a sheet having a net-like structure such as a net-like body formed by folding many filaments. Note that these network structures include, for example, a structure in which a large number of filaments are arranged in one direction, and a structure having a water-permeable void in which a large number of hemispherical projections are laminated.

Since such a net-like structure sheet has a large number of filaments folded and fused or adhered at the portions where the filaments cross each other, they have appropriate tensile strength evenly in all directions, and more sufficiently Since it has various voids, it has characteristics of excellent water permeability, and due to the fact that the filaments overlap each other, a suitable bulkiness occurs, and this structure exhibits excellent cushioning and cushioning properties, etc. without impairing water permeability. It has the effect of improving the wave resistance.

The average diameter of the filaments constituting the network structure sheet, that is, the network structure sheet comprising the soft thermoplastic resin filaments, is preferably 0.5 to 2.0 mm, and more preferably Is 0.5 to 2.0 mm. If the diameter is too thin, the filaments are easily cut due to rubbing with the stones. Conversely, if the diameter is too thick, it becomes difficult to obtain an appropriate basis weight and loop shape, and the rigidity of the sheet itself increases, resulting in handling and construction. There is a tendency for sex to deteriorate.

Next, the fibers constituting the fibrous sheet as the base material are generally preferably fibers made of polymers such as polyester, polyamide and polypropylene. Further, among these fibers, when strength characteristics are required, a nonwoven fabric composed of long fibers is preferably used. Further, since it is used outdoors for a long period of time, for example, when a nonwoven fabric made of polyester fiber is used, by incorporating carbon black, weather resistance can be improved. Such carbon black is preferably contained in the range of 0.2 to 0.6% with respect to the weight per 1 m ² . The content may be any of impregnation, coating, and primary coating, but primary coating is preferable from the viewpoint of durability and the like. If it is less than 0.2%, the weather resistance cannot be expected to increase, and if it exceeds 0.6%, the needle resistance in the production process of the non-woven fabric tends to increase and the productivity tends to deteriorate, which is not preferable.

The average single yarn fineness of the fibers constituting the non-woven fabric is preferably in the range of 1 to 10 d from the viewpoint of physical properties required for the non-woven fabric, particularly strength and cushioning property, and water permeability. In the nonwoven fabric of the present invention, fibers having different fineness may be mixed as the fibers to be used, and the average single yarn fineness may be in the above range. The basis weight of such a nonwoven fabric is 100 to 1000 g / m ² , more preferably 20.
0 to 400 g / m ² is preferable. The thickness of the non-woven fabric is preferably 1 mm or more, more preferably 3 to 4 mm, from the viewpoint of cushioning. The basis weight and thickness here are numerical values of only the non-woven fabric excluding the network structure sheet made of the soft thermoplastic resin filament.

The above-mentioned non-woven fabric is described as a non-woven fabric composed of fibers having a uniform fiber density and the same single yarn fineness. In the present invention, the non-woven fabric is composed of fibers of different fineness. Even non-woven
Further, even if it is a laminate made of a non-woven fabric of different fineness density,
Further, a non-woven fabric obtained by mixing and mixing these may be used.

Next, a method of manufacturing the water permeable civil engineering sheet of the present invention will be described with reference to FIG. Here, a method for molding a network structure sheet made of the soft thermoplastic resin filament,
An example of the integration of the network structure sheet and the fiber sheet will be described. First, the soft thermoplastic resin melted and kneaded by the melt extruder 1 is melt extruded from the multi-filament spinneret 2 into a large number of filaments 3, and the roll 4 set below the spinneret while the filaments are still in a molten state. Pick up at. Here, if the take-up speed is made sufficiently smaller than the linear discharge speed of the filament, the filament is folded on the take-up roll 4 so as to draw a loop, and the cross-contacted portions are fused to form a net-like structure. It is formed. here,
If the fibrous sheet 5 serving as the base material is set on the roll 4 in advance, the fusion of the fibrous sheet and the surface of the fibrous sheet occurs simultaneously with the formation of the fibrous structure. Can be done efficiently. Further, when it is necessary to more firmly fuse the fiber sheet and the net-like structure to each other, a nipping is performed with a pressing roll 6 with an appropriate clearance so that the net-like structure has a desired strength of fusion and adhesion. A structure sheet can be formed.

Next, the points of processing technology in the above manufacturing method will be described. The soft thermoplastic resin forming the reticulated structure is not particularly limited as long as it is a resin satisfying the flexural rigidity described above, but the workability of the reticulated structure (the ease with which loops are generated) is taken into consideration. Then, the fluidity of the molten resin can be extruded at a melt flow rate of 10 g / 10 min or more, and it is preferable to extrude under such conditions and to set the extrusion temperature so as to satisfy this fluidity.

When the fiber sheet and the net-like structure are nipped by a pressing roll, the bulkiness of the net-like structure and an appropriate clearance are maintained so as not to impair the voids, and the net-like structure is held in a state where no bank is generated at the nip point. It is preferable. As a result, the integration can be achieved without impairing the desired cushioning property and water permeability.

The water-permeable civil engineering sheet of the present invention has a flexural rigidity of 15 to 1 according to JIS K-7106 on a fiber sheet such as a non-woven fabric.
Made of a soft thermoplastic resin of 0000 kg / cm ² ,
In addition, by integrating or adhering the network structure sheet composed of the soft thermoplastic resin filament having a Gurley type flexural softness of 20000 mg or less, the water permeability and the workability are hardly impaired, and it is flexible and excellent. Thus, it is possible to provide the dobo sheet having a cushioning effect. Particularly, it has an outstanding effect as a sheet for preventing suction and scour in underwater structures, breakwaters, river levees, etc., or as a protective material for water-proof sheets for industrial waste treatment plants.

The water-permeable civil engineering sheet of the present invention is characterized in that the network structure sheet made of the specific soft thermoplastic resin filament as described above is adopted. By adopting such a net structure sheet, it exerts an excellent cushioning function against some impact from the outside, prevents damage to the fiber sheet, and has water permeability in the vertical and in-plane directions, which makes the application Without being limited, it can be used for a wide range of construction work as described above, and since it uses a network structure sheet with low bending resistance, it does not feel discomfort when combined with a fiber sheet compared to a fiber sheet alone. It has the advantage of excellent workability.

[0022]

The present invention will be described in more detail with reference to the following examples. Example 1 A permeable civil engineering sheet is produced by the manufacturing process shown in FIG. EVA resin was melt-extruded onto the surface of the fiber sheet moving directly under the spinneret from a multi-threaded spinneret in which 180 discharge holes each having a diameter of 1 mm were arranged at a pitch of 7 mm and staggered in three rows. By making the moving speed of the fiber sheet sufficiently smaller than the linear discharge speed of the filament, the filaments are folded so as to draw a loop, and the cross contact portions are fused,
It becomes a net-like structure sheet. Here, the diameter of the filament of the net-like structure sheet is 1.2 mm, and the basis weight is 500 g / m ^2. The net-like structure sheet is placed on the nonwoven fabric, the roll clearance is set to 5 mm, and the press roll at room temperature (25 ° C.) is used. The pressure was applied under the conditions of nip pressure of 6 kg / cm ² . Here, as the non-woven fabric sheet, a polyester long-fiber non-woven fabric having a single yarn of 3.0 d and a basis weight of 300 g / m ² was used. Furthermore, since the filaments of the network structure sheet are still in a semi-molten state when they reach the surface of the fiber sheet, at the same time when the network structure sheet is formed, fusion to the surface of the fiber sheet occurs, resulting in an integrated laminated sheet. Formed.

In order to evaluate the performance of the laminated sheet thus obtained as a water-permeable civil engineering sheet, the following three levels were prepared as comparative examples.

Comparative Example 1 Single yarn 3.0d used in Example 1 and basis weight 300g / m ²
The polyester long-fiber non-woven fabric of was used alone.

COMPARATIVE EXAMPLE 2 The nonwoven fabric of Comparative Example 1 having a high basis weight, that is, a basis weight of 930
A non-woven fabric of g / m ² (thickness 9.0 mm) was used. Comparative Example 3 A mesh body was laminated by the same manufacturing method as in Example 1, but polypropylene, which is a hard thermoplastic resin, was used in place of EVA as a resin forming the mesh structure sheet.

With respect to these four levels, the breakage of the sheet due to the friction between the wave and the split stone was confirmed in the wave-making water tank that artificially generated waves. As shown in Fig. 2, an embankment made of crushed stone was created in the water tank, assuming an actual sea levee, and a sheet was laid on this slope to cause waves.

Table 1 shows the time when holes were made in the sheet and the bending resistance of the laminated sheet. From the test results in the actual sea and the test results in the wave-making water tank, it was found that the test results in the wave-making water tank under the following conditions were equivalent to one month in the real sea when operated for 24 hours. [Wave-making water tank test conditions] Water tank width: 1.0 m Water depth: 68 cm Wave height: 34 cm Wavelength: 1.4 m Cycle: 2 seconds Number of waves: 43200 times / day Embankment material: Split stone (grain size: 15-30 cm) Gradient: 1 : 1.2

[Table 1] As is clear from Table 1, the sheet of Example 1 exhibited a remarkable effect of improving durability as compared with the non-woven fabric single sheet. In Comparative Example 2, the fabric weight of the fiber sheet is tripled,
It remains a proportional effect. Polypropylene (JIS
In the case of Comparative Example 3 in which a mesh body having a flexural rigidity of K-7106 of 9000 kg / cm ² ) is laminated, it has a high bending resistance and is difficult to lay, and even if it is laid, the mesh body cracks and is cut at an early point. However, the dramatic effect as in Example 1 did not appear. It is considered that this is because the wave energy was concentrated only on the net because the resin used for the net was not appropriate in flexibility and elasticity.

[0028]

According to the water-permeable civil engineering sheet of the present invention, it is possible to provide a water-permeable civil engineering sheet that is remarkably excellent in cushioning property and durability while maintaining the water permeability and workability of the conventional civil engineering construction sheet. You can

[Brief description of drawings]

FIG. 1 is a manufacturing process diagram of a water-permeable civil engineering sheet according to the present invention.

FIG. 2 shows the implementation status of a durability test in a wave-making water tank assuming an actual sea dike.

[Figure 3] Detailed view of the embankment in the wave-making water tank

[Explanation of symbols]

 1: Melt extruder 2: Multi-thread spinneret 3: Filament 4: Take-up roll 5: Fiber sheet 6: Press roll

Claims (19)

[Claims] 1. A laminated sheet in which a network structure sheet made of a soft thermoplastic resin filament and a fiber sheet are integrated with each other, and the water permeability of the laminated sheet is 1 × 10.
A water-permeable civil engineering sheet characterized by a speed of ² cm / sec or more. 2. The water-permeable civil engineering sheet according to claim 1, wherein the soft thermoplastic resin has a flexural rigidity according to JIS K-7106 in the range of 30 to 2000 kg / cm ² . 3. The soft thermoplastic resin is 50-1000.
The water-permeable civil engineering sheet according to claim ² , wherein the bending rigidity is in the range of kg / cm ² . 4. The laminated sheet has a Gurley type bending resistance of 20.
The water-permeable civil engineering sheet according to claim 1, which has a bending resistance of 000 mg or less. 5. The water-permeable civil engineering sheet according to claim 1, wherein the reticulated structure sheet includes a structure in which a large number of linear or strip filaments are arranged in a lattice. 6. The water-permeable civil engineering sheet according to claim 1, wherein the soft thermoplastic resin filament has an average diameter of 0.2 to 5.0 mm. 7. The water-permeable civil engineering sheet according to claim 1, wherein the soft thermoplastic resin is made of EVA. 8. The fiber sheet comprises 100 to 1000 g /
The water-permeable civil engineering sheet according to claim 1, which has a basis weight of m ² . 9. The water-permeable civil engineering sheet according to claim 1, wherein the fibrous sheet is a non-woven fabric or a woven or knitted fabric. 10. The water-permeable civil engineering sheet according to claim 1, wherein the fibrous sheet is a needle punched nonwoven fabric. 11. The fiber sheet has an average single yarn fineness of 1 to
The water-permeable civil engineering sheet according to claim 1, which is composed of fibers in the range of 10 d. 12. The water-permeable civil engineering sheet according to claim 1, wherein the fiber sheet is made of polyester fiber. 13. The water-permeable civil engineering sheet according to claim 1, wherein the fiber sheet contains carbon black. 14. The water-permeable civil engineering sheet according to claim 1, wherein the laminated sheet has a thickness of 2 to 20 mm. 15. The permeable civil engineering sheet according to claim 1, wherein the civil engineering sheet is for water works. 16. A permeable civil engineering sheet characterized in that after a soft thermoplastic resin is melt extruded to form a filament, the filament is laminated on the surface of the fiber sheet and fused while the filament is still in a molten state. Production method. 17. A method of laminating on the surface of the fiber sheet,
The method for producing a water-permeable civil engineering sheet according to claim 16, wherein the filament is a method of forming a network structure on the fiber sheet. 18. The method for producing a water-permeable civil engineering sheet according to claim 16, wherein the pressure-bonding is performed while maintaining a clearance that maintains the shape of the thermoplastic resin filament. 19. The method for producing a water-permeable civil engineering sheet according to claim 18, wherein the clearance is adjusted so that the thickness reduction rate of the thermoplastic resin filament layer before and after the pressing is 5 to 50%.