JPH06299455A - Laminated sheet for civil work - Google Patents

Abstract

PURPOSE:To provide a laminated sheet remarkably high in both strength and elastic modulus in comparison with conventional needle-punched nonwoven fabric sheets and particularily suitable as a protecting material for water-barrier sheets and as a sheet for reinforcing the ground. CONSTITUTION:The laminated sheet for civil works is characterized by integrating a net and nonwoven fabric sheets laminated to both the front and back surfaces of the net by a needle punching treatment, the net being produced by knitting filaments having a breakage strength of >=6.0g/denier and a stress of >=2.0g/denier under an elongation of 3% in the warp direction and in the weft direction at distances of 1-10mm and having a breakage strength of >=150kg/5cm and a stress of >=30kg/5cm under an elongation of 3%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a net in which fibers are knitted at specific intervals and a non-woven sheet laminated on both front and back surfaces of the net, which are integrated by a needle punching process. The present invention relates to a laminated sheet for civil engineering, which is suitable as a protective material or a sheet for ground reinforcement.

[0002]

2. Description of the Related Art In recent years, a non-woven sheet has been adopted as a protective material for a water impermeable sheet and a sheet for ground reinforcement. As the non-woven sheet, a non-woven sheet is generally used in which a long fiber web is needle-punched to have strength and elastic modulus. However, such a nonwoven sheet is still inadequate in terms of its strength and elastic modulus in view of the performance required for the above-mentioned application. For example, protective materials for water-impervious sheets and ground reinforcement sheets are required to have the ability to withstand the impact of the protrusions of the ground and the impact of running construction vehicles during construction. When the needle punched non-woven sheet is used, if the needle punched non-woven sheet has low strength and elasticity, the sheet is rolled due to the impact as described above, so that the thickness thereof becomes thin, and as a result, the water-impervious sheet. The impact is easily propagated to the water-permeable sheet itself, or the impact is directly transmitted to the ground reinforcement sheet, which damages the reinforcement sheet, which reduces the protective performance. Various proposals have been made to solve the above problems and improve the strength and elastic modulus, which are the drawbacks of conventional needle punched nonwoven sheets. For example, Japanese Patent Laid-Open No. 51-
JP-A-133583 discloses that a nonwoven web is needle-punched from one side, heat-set, and then needle-punched from the other side, thereby suppressing damage to the fiber due to needling and entangling the fibers. A method for improving the compatibility to obtain a non-woven sheet having high strength and high elastic modulus has been proposed. Further, Japanese Patent Publication No. 60-254543 discloses that an oil agent is applied in advance to reduce the needle penetration resistance and the punch density is increased before the needle punching treatment to improve the entanglement of fibers and improve the entanglement. Methods have been proposed for obtaining non-woven sheets having high strength and high modulus. However, both of the methods are intended to improve the strength and elastic modulus of the needle punched nonwoven sheet by improving the entanglement property between fibers. It was still inadequate with respect to both performances of elasticity and elastic modulus. Moreover, in the former method,
Since the needle punching process is performed twice on each side of the nonwoven web, the process becomes complicated and the product cost is increased.

[0003]

DISCLOSURE OF THE INVENTION The present invention is intended to solve the above problems and to provide a laminated sheet for civil engineering, which is particularly suitable as a protective material for a waterproof sheet or a sheet for ground reinforcement.

[0004]

The present inventors have arrived at the present invention as a result of extensive studies to solve the above problems. That is, the present invention is a laminated sheet for civil engineering in which a net formed by knitting long fibers and a non-woven sheet laminated on both front and back surfaces of the net are integrated by needle punching, and the net is formed. The breaking strength T _{1 of the} continuous fiber and the stress t ₁ at 3% elongation satisfy the following equations (1) and (2), respectively, and the breaking strength T _{2 of the} net is 3%.
The stress t ₂ at the time of extension is expressed by the following equations (3) and (4), respectively.
The gist is a laminated sheet for civil engineering that satisfies the above requirement. T ₁ (g / denier) ≧ 6.0 (1) t ₁ (g / denier) ≧ 2.0 ... (2) T ₂ (kg / 5cm) ≧ 150 ・ ・ ・ ・ ・ (3) t ₂ (kg / 5cm) ≧ 30 ・ ・ ・(4)

Next, the present invention will be described in detail. The net used in the present invention is composed of polyester-based polymers, polyvinyl alcohol-based polymers, or long fibers made of glass. Examples of the polyester polymer include polyethylene terephthalate, polybutylene terephthalate having a fiber-forming property, or acid components such as phthalic acid, isophthalic acid, glutaric acid, adipic acid, sulfoisophthalic acid, etc. containing these as main components, diethylene glycol, propylene glycol, 1 , 4-butanediol, 2,2-bis (4-hydroxyateoxyphenyl) propane, bisphenol A, polyalkylene glycol and other diol components are copolymerized in the range of up to 15 mol% Examples of the polyvinyl alcohol-based polymer include polyvinyl alcohol having a fiber-forming property or copolymerized polyvinyl alcohol in which ethylene, vinylpyrrolidone or other vinyl group is copolymerized in an amount of 10 mol% or less, preferably 2 mol% or less. And the like. In the present invention, when the polyester-based polymer or polyvinyl alcohol-based polymer is used as the fiber material, the polymer contains a light-resistant agent, a heat-resistant agent, an ultraviolet absorber, a stabilizer, which are usually used for fibers. Agents and the like can be added as long as the effects of the present invention are not impaired. Further, as the glass, any glass having a normal fiber forming property may be used.

In the net used in the present invention, the breaking strength T _{1 of the} constituent fibers and the stress t ₁ at the time of 3% elongation must satisfy the above equations (1) and (2), respectively. In this net, if the breaking strength T ₁ of the fiber is less than 6.0 g / denier and the stress t ₁ at 3% elongation is less than 2.0 g / denier, it will be pressed by the ground protrusion and the construction vehicle under construction. It is not possible to satisfy the performance required to withstand the impact of running.

The net used in the present invention is composed of long fibers satisfying the above formulas (1) and (2), and has a required performance as a protective material for a water impervious sheet or a ground reinforcing sheet, that is, compression by a protrusion of the ground. From the viewpoint of the performance of withstanding the impact due to the traveling of the construction vehicle during construction and the construction, the breaking strength T _{2 of the} net and the stress t ₂ at the time of 3% elongation are respectively expressed by the formula (3).
And (4), and the fibers are knitted in the warp direction and the weft direction at intervals of 1 mm or more and 10 mm or less. In this net, if the breaking strength T ₂ of the net is less than 150 kg / 5 cm and the stress t ₂ at 3% elongation is less than 30 kg / 5 cm, even if the breaking strength T _{1 of the} constituent fibers and the stress t at 3% elongation are t. _{Even if 1} and ₁ respectively satisfy the above equations (1) and (2), the net itself lacks the ability to withstand the impact and the like, and the effect of the reinforcement intended by the present invention cannot be obtained. When the spacing between the constituent fibers in the net is less than 1 mm in both the warp direction and the weft direction, the above-mentioned required performance is sufficiently achieved, but the sand and sand are likely to be clogged in the meshes, and the water permeability is lowered.
If this distance exceeds 10 mm in both the warp direction and the weft direction, the ability to withstand the above-mentioned impact and the like becomes insufficient.

The non-woven sheet used in the present invention is, for example, polyethylene terephthalate, polybutylene terephthalate or a polyester polymer such as the above-mentioned copolyester, low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene. Density polyethylene,
Polyolefin polymers such as crystalline polypropylene or polycapramide, polyhexamethylene adipamide,
It is composed of long fibers made of a polyamide-based polymer such as polytetramethylene adipamide and is produced by, for example, a so-called spunbond method. The single yarn fineness of the long fibers is not particularly limited, but preferably 1 denier or more and 20 denier or less. When the single yarn fineness is less than 1 denier, when a nonwoven sheet made of this fiber is laminated on both sides of the net and needle punched, the fiber is cut and the sheet strength is lowered, and the sheet has a polyme feel. Impaired, while single yarn fineness is 2
If it exceeds 0 denier, the entanglement between the fibers and the constituent fibers of the net becomes insufficient, and integration cannot be obtained, either of which is not preferable. The form of the long fiber is not particularly limited, and for example, in addition to a single polymer, two or more kinds of polymers are combined into a bonded type, a concentric sheath type or an eccentric sheath type. It may have been done. Also,
The cross-sectional shape is not particularly limited, and may be, for example, an ordinary cross section, or a modified cross section such as a triangular shape, a square shape, or the like. The basis weight of the non-woven sheet is not particularly limited and may be appropriately washed according to the application, but from the viewpoint of the surface smoothness of the product sheet, the impact resistance, and the water permeability, it is 30 g / m ² or more and 1000 g or more. / M ²
The following is preferable.

The laminated sheet of the present invention comprises the specific net and the non-woven sheet laminated on both front and back surfaces thereof, which are integrated by needle punching. This needle punching process has a needle density of 20 times / cm ²
It is preferably 150 times / cm ² or less.
If the needle density is less than 20 times / cm ² , the entanglement between the net and the non-woven sheets laminated on both front and back surfaces of the net may be insufficient, resulting in peeling between the sheets. When the density exceeds 150 times / cm ² , the entanglement between the net and the non-woven sheet is improved,
When the needle collides with the net, the surface of the product sheet has an uneven shape, and the needle is worn or broken during processing, which is not preferable.

The laminated sheet of the present invention is subjected to heat treatment or resin impregnation treatment for the purpose of further improving the bondability between the specific net and the non-woven sheet laminated on both front and back surfaces thereof. Good. As the heat treatment, after laminating the non-woven sheets on both front and back surfaces of the specific net, for example, a method of hot pressing the laminated sheets by using a hot pressing roller, and an embossing roll having protrusions on the surface and heated An embossing method of passing a laminated sheet between a metal roll with a smooth surface and a heated surface, a method of using an ultrasonic fusing device, a method of shrinking the non-woven sheet itself using a hot air dryer, and joining it to a net are used. Can be adopted. When the embossing roll is used, the shape of the protrusion of the embossing roll, that is, the form of the crimping point is not particularly limited. For example, in addition to the ordinary round shape, an oval shape, a rhombus shape, a triangular shape, a T shape, a − shape, Any form such as a well type or a lattice type may be used. As the resin impregnation treatment, after laminating the non-woven sheets on both front and back surfaces of the specific net,
For example, using a general resin such as acrylic ester resin, epoxy resin, or phenol resin, the laminated sheet is immersed in a resin tank, squeezed by a squeezing means such as a mangle roll, and then dried by a band dryer. A method of applying a resin foam foamed by a foaming machine to a laminated sheet and then drying it with a hot air dryer can be adopted.

In the laminated sheet of the present invention, long fibers having the specific breaking strength and the stress at 3% elongation are knitted in the warp direction and the weft direction at intervals of 1 mm or more and 10 mm or less, and the specific breaking strength is And a non-woven sheet laminated on both front and back surfaces of the net and having a stress at the time of 3% elongation are integrated by a needle punching process. Since a strong and high-modulus net is placed in the intermediate layer of the non-woven sheet, it is stronger than the conventional needle-punched non-woven sheet in which strength and elastic modulus are improved by improving the entanglement between fibers. As a result, both strength and elastic modulus are significantly improved. Moreover, in this laminated sheet, it is possible to widely meet the required performance of the product sheet by appropriately changing the material of the net and the fiber arrangement in the warp direction and / or the weft direction.

[0012]

EXAMPLES Next, the present invention will be specifically described based on Examples. The measurement and evaluation of various characteristics in the examples were carried out by the following methods. Melting point of polymer: Differential scanning calorimeter D manufactured by Perkin Elmer
The melting point was defined as the temperature at which the exothermic value of the melting and absorption heat curve measured using the SC-2 type at a temperature rising rate of 20 ° C./min. Intrinsic viscosity: The intrinsic viscosity of the polyester polymer was measured by the following method. That is, the measurement was carried out at a temperature of 20 ° C. using a mixed solution of equal weight of phenol and ethane tetrachloride as a solvent. Relative viscosity: The relative viscosity of the polycapramide polymer was measured by the following method. That is, using sulfuric acid having a concentration of 96% by weight as a solvent, a sample concentration of 1 g / 100 cc, and a temperature of 25 ° C.
It was measured at. Fiber breaking strength T ₁ (g / denier): JIS L-1
According to the method described in 069, using a constant-speed elongation type tensile tester (Tensilon manufactured by Orienteik Co., Ltd.), measurement was performed at a tensile speed of 20 cm / min for 10 points of the sample, and the average value of the obtained breaking strength was measured. The strength was T ₁ (g / denier). Stress t ₁ (g / denier) at 3% elongation of fiber: JIS
Sample 10 according to the method described in L-1069.
The load value at 3% elongation was measured at a tensile rate of 20 cm / min for each point, and each load value was divided by the fiber fineness (denier), and the average value was calculated as the stress t ₁ ( g / denier). Sheet breaking strength T ₂ (kg / 5 cm): JIS L-
According to the strip method described in 1096, a constant-speed extension type tensile tester (Tensilon manufactured by Orienteik Co., Ltd.)
The tensile strength of the sheet was measured at 10 points with a sample length of 10 cm and a sample width of 5 cm at a tensile speed of 10 cm / min, and the average value of the breaking strength obtained was taken as the breaking strength T ₂ (kg / 5 cm) of the sheet. Stress t ₂ at 3% elongation of sheet (kg / 5 cm): JI
According to the strip method described in SL-1096, the load value at the time of 3% elongation was measured for each of the 10 points of the sample at a tensile speed of 10 cm / min, each load value was divided by the sample width of 5 cm, and the average value was used as a sheet. Stress at ₂ % elongation t ₂ (kg / 5c
m).

Impact resistance (mm) of the sheet: The impact resistance of the sheet was evaluated by the following method. First, the length is 1.1
A resin hollow cylindrical body having an inner diameter of 7.5 cm and an inner diameter of 7.5 cm and a smooth inner surface was prepared. Next, a polyethylene polymer sheet having a thickness of 2 mm was placed on a support plate, a sample piece of a laminated sheet was placed on the polyethylene polymer sheet, and the cylindrical body was placed on the sample piece in the vertical direction of the long axis. Then, a drop test in which the weight is dropped from above the cylinder to the bottom is performed on four sample pieces, and the weight is pierced in each test, and the drop of the hole formed in the polyethylene polymer sheet is performed. The impact resistance (mm) of the laminated sheet was evaluated by measuring the size (mm). When performing a drop test, the axial cross-section has a truncated cone shape with a cone angle of 60 ° at the bottom, and the upper diameter D has a diameter that abuts the inner diameter of the cylindrical body. Is d (mm) and the weight is W (k
g) A weight was used, and the distance between the tip surface of the weight, that is, the lower surface of the truncated cone and the sample piece, that is, the fall distance was 1.0 m. In addition, the weight W has a weight W of 3.8 kg and a lower diameter d.
4 weights of 3 mm, 3 mm at 7.4 kg, 8 mm at 7.4 kg, and 10 mm at 11.3 kg were used.

Example 1 First, a polymer having a melting point of 260 ° C. and an intrinsic viscosity of 0.68 is used.
Using ethylene terephthalate polymer, the spinning temperature is 28
Spinning having 248 spinning holes with a diameter of 0.3 mm at 5 ° C
Melt spinning through the die, take-up speed is 4500m / min
After pulling and picking up with an air cleaner, open the fibers continuously
And then deposit it on a moving conveyor to create a long fiber web.
did. Then, the web was hot-pressed at a temperature of 180 ° C.
The single yarn fineness is 3.0 deniers
And the basis weight is 100 g / m²Create a non-woven sheet of
did. Separately, polyethylene terephthalate with an intrinsic viscosity of 0.75
Made of a talate polymer, with a fiber diameter of 1.0 mm and breaking strength
Degree T₁Is 6.5 g / denier, stress t at 3% elongation₁But
2.5 g / denier single fiber, warp and weft directions
Both are knitted with 4.0 mm and the basis weight is 180 g / m²of
I made a net. This net has a breaking strength T ₂Is 18
Stress t at 0 kg / 5 cm, 3% elongation₂Is 40 kg / 5
It was cm. Next, obtain the above on both sides of the net.
3 non-woven sheets are laminated to each and made by Organ
Needle pan equipped with a needle (PPD-1 40)
Using a machine, the needle density is 89 times / cm²As knee
A dollar punching process was performed to obtain a laminated sheet. Obtained product
Layer sheet mechanical properties and impact resistance by drop test (m
The evaluation results of m) are shown in Table 1. In Table 1, P
ET is polyethylene terephthalate, T₁Breaks the fiber
Strength, t₁Is the stress at 3% elongation of the fiber, T₂Is net
Breaking strength, t₂Is the stress at the time of 3% elongation of the net, T_SIs product
Breaking strength of ply sheet, t_SIs for 3% elongation of laminated sheet
Stress, MD indicates the warp direction, and CD indicates the weft direction.

Example 2 A net was made of a polyethylene terephthalate polymer having an intrinsic viscosity of 0.75, a fiber diameter of 0.8 mm, a breaking strength T ₁ of 7.0 g / denier and a stress t _{1 of} 3% elongation.
Of 3.5 g / denier is knitted in 2.0 mm in both warp and weft directions, the basis weight is 200 g / m ² , the breaking strength T ₂ is 220 kg / 5 cm, and the stress t at 3% elongation is t.
_A laminated sheet was obtained in the same manner as in Example 1 except that ₂ was 55 kg / 5 cm. Table 1 shows the evaluation results of the mechanical properties of the obtained laminated sheet and the impact resistance (mm) by the drop test.

Example 3 The laminated sheet obtained in Example 1 was heat-pressed using a hot-pressing roll at a temperature of 230 ° C., and then impregnated with a mixed resin of urea melamine resin and acrylic ester resin, A resin-impregnated laminated sheet was obtained. Table 1 shows the evaluation results of the mechanical properties of the obtained laminated sheet and the impact resistance (mm) by the drop test.

Example 4 As a net, a polyvinyl alcohol polymer was used,
A single fiber having a fiber diameter of 1.2 mm and a breaking strength T ₁ of 6.8 g / denier and a stress t ₁ at 3% elongation of 2.4 g / denier is knitted at 4.0 mm in both the warp direction and the weft direction. Of 250 g / m ² and breaking strength T ₂ of 260 kg / 5
cm, a laminated sheet was obtained in the same manner as in Example 1 except that the stress t ₂ at the time of elongation of 3% was 60 kg / 5 cm. Table 1 shows the evaluation results of the mechanical properties of the obtained laminated sheet and the impact resistance (mm) by the drop test. Table 1
In, PVA represents polyvinyl alcohol.

Example 5 As a net, a polycapramide polymer having a relative viscosity of 3.0, a fiber diameter of 1.2 mm and a breaking strength T ₁ of 7.
Single fibers with 0 g / denier and a stress t ₁ of 3.0 g / denier at 3% elongation were knitted with 3.0 mm in both warp and weft directions, the basis weight was 250 g / m ² , and the breaking strength T ₂ was 2.
60 kg / 5 cm, stress t ₂ at 3% elongation is 55 kg /
A laminated sheet was obtained in the same manner as in Example 1 except that the sheet having a thickness of 5 cm was used. Table 1 shows the evaluation results of the mechanical properties of the obtained laminated sheet and the impact resistance (mm) by the drop test. In Table 1, N6 represents polycapramide (nylon 6).

Example 6 A net having a fiber diameter of 0.8 mm, a breaking strength T ₁ of 6.2 g / denier and a stress t ₁ at 3% elongation of 5.8 g.
/ Denier glass filaments in both warp and weft directions 2.
Lamination was performed in the same manner as in Example 1 except that the knitting was performed at 0 mm, the basis weight was 230 g / m ² , the breaking strength T ₂ was 240 kg / 5 cm, and the stress t ₂ at 3% elongation was 230 kg / 5 cm. Got the sheet. Table 1 shows the evaluation results of the mechanical properties of the obtained laminated sheet and the impact resistance (mm) by the drop test. In addition, in Table 1, G shows glass.

[0020]

[Table 1]

Comparative Example 1 A laminated sheet was obtained in the same manner as in Example 1 except that no net was used and a total of 8 nonwoven sheets were laminated. Mechanical properties of the obtained laminated sheet and impact resistance (m in drop test)
The evaluation results of m) are shown in Table 2.

COMPARATIVE EXAMPLE 2 The laminated sheet obtained in Comparative Example 1 was subjected to a thermocompression-bonding treatment using a thermocompression-bonding roll at a temperature of 230 ° C. and then impregnated with a mixed resin of urea melamine resin and acrylic ester resin, A resin-impregnated laminated sheet was obtained. Table 2 shows the evaluation results of the mechanical properties of the obtained laminated sheet and the impact resistance (mm) by the drop test.

Comparative Example 1 A net was made of a polyethylene terephthalate polymer having an intrinsic viscosity of 0.75, a fiber diameter of 1.2 mm, a breaking strength T ₁ of 6.5 g / denier and a stress t _{1 of} 3% elongation.
Of 2.5 g / denier monofilament is knitted in 20 mm in both warp and weft directions, the basis weight is 200 g / m ² , the breaking strength T ₂ is 40 kg / 5 cm, and the stress t ₂ at 3% elongation is 15 kg / 5 cm. A laminated sheet was obtained in the same manner as in Example 1 except that the above sheet was used. Table 2 shows the evaluation results of the mechanical properties of the obtained laminated sheet and the impact resistance (mm) by the drop test.

Comparative Example 2 As a net, a polyvinyl alcohol polymer was used.
A single fiber having a fiber diameter of 1.2 mm, a breaking strength T ₁ of 6.8 g / denier, and a stress t ₁ of 3% elongation of 2.4 g / denier is knitted at 15 mm in both warp and weft directions, and has a basis weight of 200 g. / M ² and breaking strength T ₂ is 60 kg / 5c
A laminated sheet was obtained in the same manner as in Example 1, except that the stress t ₂ at the time of elongation of 3 m and 3% was 10 kg / 5 cm. Table 2 shows the evaluation results of the mechanical properties of the obtained laminated sheet and the impact resistance (mm) by the drop test.

[0025]

[Table 2]

As is clear from the table shown in Table 1,
In the laminated sheets obtained in Examples 1 to 6 satisfying the constitution requirements of the present invention, a high-strength and high-modulus net made of high-strength and high-modulus fibers is arranged in the intermediate layer of the non-woven sheet. Therefore, the fracture strength and the stress at 3% elongation are both high,
The protection performance was excellent. On the other hand, Comparative Example 1
The laminated sheets of Nos. 1 and 2 and the laminated sheets of Comparative Examples 1 and 2 which do not satisfy the constitutional requirements of the present invention have a low stress particularly at 3% elongation, as is clear from Table 2.
The protection performance was poor.

[0027]

EFFECT OF THE INVENTION In the laminated sheet for civil engineering of the present invention, long fibers having the above specific breaking strength and stress at 3% elongation are knitted in the warp direction and the weft direction at intervals of 1 mm or more and 10 mm or less, and A net having a specific breaking strength and a stress at 3% elongation and a non-woven sheet laminated on both the front and back surfaces of the net are integrated by needle punching, and have high strength and high elastic modulus. Since a high-strength, high-elasticity net made of fibers is arranged in the intermediate layer of the non-woven sheet, both the strength and the elastic modulus are significantly higher than those of the conventional needle-punched non-woven sheet. It is suitable as a protective material and a ground reinforcing sheet. Further, by appropriately changing the material of the net and the fiber arrangement in the warp direction and / or the weft direction, it becomes possible to widely meet the required performance of the product sheet.

Claims (4)

[Claims] 1. A laminated sheet for civil engineering, comprising a net formed by knitting long fibers and a non-woven sheet laminated on both front and back surfaces of the net, which are integrated by needle punching, and which constitutes the net. Breaking strength of long fibers T ₁ and 3
The stress t ₁ at the time of elongation satisfies the following equations (1) and (2), respectively, and the breaking strength T _{2 of the} net is 3%.
The stress t ₂ at the time of extension is expressed by the following equations (3) and (4), respectively.
A laminated sheet for civil engineering that satisfies the requirements. T ₁ (g / denier) ≧ 6.0 (1) t ₁ (g / denier) ≧ 2.0 ... (2) T ₂ (kg / 5cm) ≧ 150 ・ ・ ・ ・ ・ (3) t ₂ (kg / 5cm) ≧ 30 ・ ・ ・(4) 2. The laminated sheet for civil engineering according to claim 1, wherein the constituent fibers of the net are knitted at intervals of 1 mm or more and 10 mm or less in both warp and weft directions. 3. The civil engineering laminated sheet according to claim 1, wherein the constituent fibers of the net are polyester long fibers or polyvinyl alcohol long fibers. 4. The laminated sheet for civil engineering according to claim 1, wherein the constituent fibers of the net are glass-based long fibers.