WO2015122440A1 - Under-gravel sheeting - Google Patents

Abstract

　An objective of the present invention is to provide under-gravel sheeting that is for use in agriculture or civil engineering, and that is laid on soil to prevent the subsidence of gravel and to suppress the growth of weeds, etc., said under-gravel sheeting having excellent anti-gravel subsidence properties, workability and shading properties.　The present invention relates to under-gravel sheeting comprising a woven article in which a multi-filament thread is used for the warp thread and the weft thread, wherein the woven article has a cover factor of at least 2000, a bending resistance of 50-100mm, a fixed expansion load of 70-300N, and a shading rate of at least 95%.

Description

Gravel bottom sheet

The present invention relates to a gravel bottom sheet laid on soil used in the agricultural field and civil engineering field. The gravel bottom sheet is used to prevent sedimentation of gravel and to suppress the growth of weeds from the soil.

The gravel bottom sheet is used to prevent sedimentation of gravel and to prevent weeds from growing in order to maintain the beauty of buildings and roadside trees. The gravel bottom sheet is also used as an underlay when placing asphalt or concrete on the levee slope for road construction or river bank protection. Furthermore, it may be used directly for cultivation of weeds by laying directly on the cultivation ground such as an orchard or vegetable garden.

Conventionally, gravel was laid directly on the soil without using a gravel bottom sheet, so gravel sinks into the soil during construction, reducing the thickness of the gravel layer and the load on the gravel. However, there was a case where the necessary supporting force was not obtained. In addition, when there was rainfall or groundwater infiltration, the soil and gravel layer weakened, and when a heavy vehicle such as an automobile passed over the gravel, the gravel settled and dredging occurred on the road surface. In addition, when a car or the like passes over a ridge where water has accumulated, the road surface is disturbed by the tire, and the ridge may become deeper. In order to repair this drought phenomenon, gravel had to be laid from the top of the dredge, and the cost was not negligible.

In order to solve such a problem, a means of laying a vinyl sheet, a rubberized woven sheet or the like on the soil has been taken. However, these sheets are hard, and problems such as sheet folding and wrinkles occur during construction, or they do not follow uneven soil, and it is necessary to level the ground before construction to eliminate undulations. Further, since these sheets have no water permeability, there is a problem that water accumulates on the sheet surface due to rain or the like, and the gravel layer is submerged.

Therefore, in recent years, permeable gravel sheets and permeable grass protection sheets have been created. For example, the lower gravel sheet is a sheet to which water permeability and light shielding properties are added using a dark-colored spunbond nonwoven fabric, and an effect of preventing sedimentation of gravel and an effect of preventing the overgrowth of weeds are seen. However, since the sheet is hard, it is difficult to perform the construction, and since it is difficult to follow the undulations of the soil, an improvement from the viewpoint of economy has been desired, for example, a prior leveling work is necessary.

Patent Document 1 discloses a sheet having a light shielding property and water permeability, which is made of a flat yarn woven fabric containing carbon black. The said sheet | seat aims at the effect which prevents the overgrowth of weeds. However, since the sheet uses a flat yarn having a single yarn fineness of 500 dtex or more, the sheet is hard and the workability is not sufficient.

Patent Document 2 discloses a sheet having light shielding properties and water permeability, which is made of a woven fabric of flat yarn having a porosity of 6.0% or less. The sheet is also intended to prevent the growth of weeds. However, since the sheet also uses a flat yarn having a single yarn fineness of 500 dtex or more, the sheet is hard and has poor workability. The sheet also has a function of preventing weeds from dying by providing the sheet with some voids and translucency, and therefore the void ratio is preferably 0.1% or more. It is disclosed that the integrated light shielding ratio in the range of 380 to 780 μm is preferably 70 to 95%.

Japanese Patent Laid-Open No. 10-42720 JP 2006-25642 A

In view of the above situation, the present invention is a gravel bottom sheet that is laid on soil in the agricultural field and civil engineering field, and is used to prevent sedimentation of gravel and to suppress the growth of weeds. An object of the present invention is to provide a gravel bottom sheet having workability and herbicidal properties.

When the inventor softens the sheet in order to improve the workability of the lower gravel sheet, the gravel laid on the sheet may sink due to the load from above (that is, the gravel sedimentation resistance is insufficient). On the other hand, attention has been paid to the fact that if the sheet is hardened in order to improve the resistance to sedimentation of gravel, the sheet is folded or wrinkled during the construction, and the workability is impaired. And it discovered that the softness of a sheet | seat and gravel sedimentation-proof property could be made compatible by employ | adopting the precise | minute fabric using a multifilament yarn. Furthermore, by making the woven fabric into a woven fabric having a specific cover factor, bending resistance, constant elongation load, and light shielding rate, a gravel under sheet having excellent gravel sedimentation resistance, workability, and herbicidal properties can be obtained. As a result, the present invention has been completed.

That is, the present invention achieves the object described above,
(1) A gravel bottom sheet made of a woven fabric using multifilament yarns for warp and weft yarns, the woven fabric having a cover factor of 2,000 or more, a bending resistance of 50 mm to 100 mm, and a constant elongation load of 70 N The present invention relates to a gravel lower sheet having a light shielding rate of 95% or more and up to 300N.

The present invention also provides
(2) The woven fabric relates to the gravel lower sheet according to (1), wherein the total number of warp yarns and weft yarns within a 2.54 cm square is 6,000 to 10,000.

The present invention also provides
(3) The gravel bottom sheet according to (1) or (2), wherein the fineness of the single yarn constituting the multifilament yarn is 2.3 dtex to 4.6 dtex.

The present invention also provides
(4) The gravel bottom sheet according to any one of (1) to (3), wherein the total fineness of the multifilament yarn is 84 dtex to 330 dtex.

The present invention also provides
(5) The gravel bottom sheet according to any one of (1) to (4), wherein the multifilament yarn is black, gray, brown, green, or blue.

The gravel bottom sheet of the present invention has flexibility and strength while having excellent light shielding properties. That is, the gravel lower sheet of the present invention has excellent herbicidal properties, workability, and gravel sedimentation resistance. Therefore, when the gravel bottom sheet of the present invention is laid on the soil, it is excellent in the herbicidal effect, and the gravel on the surface is less likely to settle even when the vehicle is driven, and the ground can be kept in a good state. In addition, the construction is easy and the leveling work for laying the sheet can be reduced, which is advantageous in terms of work and cost.

Hereinafter, embodiments of the present invention will be described. The gravel bottom sheet of the present invention is characterized by adopting a dense fabric, and specifically comprises a fabric using multifilament yarns for warp and weft yarns, The cover factor is 2,000 or more, the bending resistance is 50 mm to 100 mm, the constant elongation load is 70 N to 300 N, and the light shielding ratio is 95% or more.

Examples of the woven fabric constituting the gravel bottom sheet of the present invention include: Mihara texture such as plain weave, twill weave and satin weave; change texture; single double texture such as warp double weave and weft double weave; Can be mentioned. Among them, a twill weave is preferably employed because it is excellent in flexibility, can be formed densely, and can improve light shielding properties.
The number of layers constituting the fabric is not particularly limited, and may be a single layer structure or a multilayer structure of two or more layers. Of these, a single layer structure is preferred because it is excellent in productivity and inexpensive.

The warp yarn of the woven fabric is preferably a multifilament yarn having the same total fineness. By using multifilament yarns having the same total fineness, it is possible to prevent a decrease in light-shielding property due to unevenness between yarns. When yarns having different total fineness are mixed and used, the average fineness is defined as the total warp fineness. The horizontal thread is the same as the warp thread.

The type of fiber used for the multifilament yarn constituting the woven fabric is not particularly limited. For example, any fiber types such as synthetic fibers such as polyester, polyamide, acrylic, polyvinyl chloride, and polyurethane, semi-synthetic fibers such as acetate, triacetate, and promix, and regenerated fibers such as rayon and cupra can be used. Of these, synthetic fibers such as polyamide and polyester are more preferred because of their good strength and weather resistance.

The total fineness of the multifilament yarn is preferably 84 to 330 dtex from the viewpoint of sheet flexibility (workability). If it is 84 dtex or more, sufficient strength can be obtained and productivity can be improved. Furthermore, the fluff of the sheet due to friction can be reduced. Moreover, if it is 330 dtex or less, the space | gap of an intersection part can be suppressed and light-shielding property improves.

The multifilament yarn can exhibit excellent light-shielding properties and can improve the design by using dark-colored original yarns such as black, gray, brown, green, and blue. Among them, it is preferable to use a black original yarn in order to further increase the light shielding rate. In order to further increase the light shielding rate, it is preferable to use a black original yarn.

The fabric weight is preferably 80 g / m ² to 160 g / m ² . If it is 80 g / m ² or more, sufficient strength can be obtained, and if it is 160 g / m ² or less, it is lightweight, so that workability and workability are improved.

The cover factor of the woven fabric is 2,000 or more, preferably 2,200 or more. If the cover factor is less than 2,000, the denseness of the fabric is lost and the gaps between the yarns are increased, so that the light shielding property is insufficient, and the effect of preventing weeds to prevent the growth of weeds is reduced. The cover factor shown here is defined (calculated) by the following formula 1.

[Formula 1]
Cover factor = A x D _A ^1/2 + B x D _B ^1/2
A: Warp density of woven fabric (line / 2.54cm)
B: Weft density of woven fabric (lines / 2.54cm)
D _A : Total fineness of warp yarn (dtex)
D _B : The total fineness of the weft yarn (dtex)

The shading rate of the fabric constituting the gravel bottom sheet of the present invention is 95% or more, preferably 98% or more. If the light shielding ratio is less than 95%, the light shielding property for preventing the weeds from growing under the sheet is insufficient, and the weeds on the ground on which the sheet under the gravel is laid may grow. The light shielding rate is a value measured according to JIS L 1055 A method (curtain light shielding property test method) as described in Examples below.

The woven fabric composing the lower gravel sheet of the present invention has a specific range of bending resistance and constant elongation load, whereby the gravel sedimentation resistance and workability of the sheet can be satisfied.
That is, the bending resistance of the fabric is 50 mm to 100 mm, preferably 60 mm to 80 mm. If it is less than 50 mm, the sheet is soft and the workability is good, but if the soil of the construction surface is a fine place of particles such as earth and sand, the gravel laid on the sheet settles over time and the gravel layer Unevenness appears on the surface. Moreover, when it exceeds 100 mm, since a sheet | seat does not follow uneven | corrugated soil, it is difficult to perform construction, and it is necessary to level the ground before construction to eliminate undulations. For this reason, not only does the work take time, but also the ground preparation cost is required and the economic efficiency is lowered.

The constant elongation load of the woven fabric is 70 N to 300 N, preferably 100 N to 190 N. If it is less than 70N, the load applied when a person or a vehicle body passes over gravel causes the sheet to follow the undulations of the soil with the sheet stretched too much, so the material of the stretched portion becomes thin. That is, there is a possibility that the strength decreases and tearing or the like occurs. Moreover, since it will be hard to extend when it exceeds 300 N, it will be difficult to follow the undulation of the soil, and it will be constructed in a state in which the sheet is broken and wrinkled, and there is a problem in appearance.

The constant elongation load and the bending resistance are considered to be affected by the fineness of the single yarn constituting the multifilament yarn and the total number of warp and weft yarns within a 2.54 cm square in the woven fabric. The constant elongation load and the bending resistance are values measured by the method described in the examples described later.

The single filament fineness of the multifilament yarn is preferably 2.3 dtex to 4.6 dtex. If it is 2.3 dtex or more, fluffing of the sheet due to friction can be reduced. Furthermore, good hardness is obtained, and the gravel sedimentation resistance is improved. Moreover, if it is 4.6 dtex or less, sufficient softness | flexibility will be obtained for a sheet | seat and workability will improve.

From the viewpoint of workability, it was found that the total number of warp yarns and weft yarns within 2.54 cm square in the woven fabric is preferably 6,000 to 10,000. If it is 6,000 or more, good hardness can be obtained and gravel sedimentation resistance can be improved. Moreover, if it is 10,000 or less, sufficient softness | flexibility will be acquired and workability | operativity will improve.

The woven fabric constituting the gravel bottom sheet of the present invention preferably has a water permeability of 1.0 × 10 ⁻³ cm / sec or more. If it is 1.0 × 10 ⁻³ cm / sec or more, rainwater can be sufficiently permeated into the soil without water accumulating on the sheet even under heavy rain. The gravel lower sheet of the present invention also has an effect of efficiently infiltrating surface moisture by capillary action by forming a high-density fabric with multifilament yarns.

Furthermore, the fabric constituting the gravel bottom sheet of the present invention may be subjected to water absorption treatment, antistatic treatment, flame retardant treatment, weather resistance treatment, sealing treatment, etc., depending on the purpose and application. Of these, the water absorption treatment is suitable for increasing the water penetration.

The gravel bottom sheet of the present invention will be described more specifically with reference to the following examples and comparative examples, but the present invention is not limited to these examples.

[Evaluation methods]
1. Flexibility (mm)
<Test conditions>
It measured according to JIS L1096 method.
2. Constant elongation load (N)
<Test conditions>
It measured according to JIS L 1096 A method.
The load at the time when the base material having a test piece width of 2.5 cm and a holding interval of 10 cm was extended by 10% was measured. (The larger the value, the less likely it is to stretch, and the smaller the value, the easier it is to stretch.)

3. Shading rate (%)
<Test conditions>
Measured according to JIS L 1055 A method (curtain shading test method).
The illuminance before mounting the test piece was 100,000 lx.
4). Friction durability (easy to tear material)
The measurement was performed according to JIS L 1096 C method (Taber type method).
<Test conditions>
Wear wheel no. CS-10, load 500gf, 1000 times <Evaluation criteria>
The surface of the test piece was confirmed by visual observation, and an unbreakable one was evaluated as “◯”, and an unbreakable one was evaluated as “x”.

5. Gravel sedimentation resistance <Test conditions>
120cm square and 30cm depth of ground, put sandy sand (particle size of 5mm or less) for leveling, leveling and compacting using a compacting machine rammer (HITACHI product number: ZV55R) Formed. Each sheet of the 100 cm square Example and Comparative Example was laid on the soil, and large nails were struck and fixed at the four corners. From there, gravel (single grain crushed stone S-20 (JIS A 5001)) was laid about 10 cm thick and leveled.
On the centerline of the gravel that was laid, the vehicle was moved forward and back by a 2t vehicle, and was reciprocated 365 times (the forward and back reciprocations were counted as one time) at a constant place.
<Evaluation criteria>
The gravel sedimentation state and sheet state after the test were confirmed.
◎ Gravel sedimentation and sheet distortion are hardly seen.
○ Gravel sedimentation and slight distortion of the sheet are observed, but the sheet is not torn.
Δ Gravel sedimentation and sheet distortion are slightly observed, and sheet tearing is slightly observed. × Gravel sedimentation and sheet distortion are observed, and sheet tearing is also frequently observed.

6). Workability (workability, soil followability)
<Test conditions>
Each sheet of the examples and comparative examples was laid on a step-shaped soil provided with a step of 10 cm in height. The space created by the step between the laid sheet and the stairs was pressed by hand, and it was applied to the soil.
<Evaluation criteria>
The soil followability of the sheet at the level difference and the workability were confirmed visually.
◎ Following is observed along the shape of the soil, there are no creases, and workability is good.
○ A little follow-up along the shape of the soil, almost no creases, and workability is slightly better.
△ Following is almost not observed along the shape of the soil, there are some wrinkles, and the workability is slightly poor.
× Follow-up is not seen along the shape of the soil, there are wrinkles, and workability is poor.

Sheets of Examples and Comparative Examples described below were woven by an air jet loom (Product Number: JAT710 manufactured by Toyota Industries Corporation).
[Example 1]
Polyester black original yarn 84dtex / 24f (manufactured by NAN YA PLASTICS CORPORATION (hereinafter, NAN YA)) for warp yarn, polyester black original yarn 84dtex / 24f (manufactured by NAN YA) for horizontal yarn, twill weave (density: warp 180) / Inch, 130 wefts / inch), a cover factor of 2684, and a total number of single yarns of 7440 were produced.

[Example 2]
Polyester black original yarn 167dtex / 36f (manufactured by NAN YA) for warp yarn, polyester black original yarn 167dtex / 36f (manufactured by NAN YA) for warp yarn, twill weave (density: warp 127 / inch, weft 85 / inch ), A fabric having a cover factor of 2599 and a total number of single yarns of 7632 was prepared.

[Example 3]
Plain weave (density: warp 144 / inch, weft 110 / inch) using polyester black original yarn 84dtex / 36f (manufactured by NAN YA) as warp yarn and polyester black original yarn 84dtex / 36f (manufactured by NAN YA) as warp yarn. ), A fabric having a cover factor of 2208 and a total number of single yarns of 9144 was prepared.

[Example 4]
Plain weave (density: warp 144 / inch, weft 110 / inch), using polyester black original yarn 84tex / 24f (manufactured by NAN YA) for warp yarn and polyester black original yarn 84dtex / 24f (manufactured by NAN YA) for warp yarn. ), A woven fabric having a cover factor of 2208 and a total number of single yarns of 6,096.

[Example 5]
Polyester black original yarn 167dtex / 36f (manufactured by NAN YA) for warp yarn, polyester black original yarn 167dtex / 36f (manufactured by NAN YA) for warp yarn, plain weave (density: warp 115 / inch, weft 55 / inch ), A woven fabric having a cover factor of 2084 and a total number of single yarns of 6120 was prepared.

[Example 6]
Plain warp yarn (density: 145 warp / inch, weft 65 inch / inch) using polyester black original yarn 167 dtex / 36f (manufactured by NAN YA) as warp yarn and polyester black original yarn 167 dtex / 36f (manufactured by NAN YA) as warp yarn ), A woven fabric having a cover factor of 2575 and a total number of single yarns of 7560 was prepared.

[Example 7]
Plain warp yarn (density: warp 80 / inch, weft 50 / inch) using polyester black original yarn 330dtex / 72f (manufactured by NAN YA) as warp yarn and polyester black original yarn 330dtex / 72f (manufactured by NAN YA) as warp yarn. ), A woven fabric having a cover factor of 2189 and a total number of single yarns of 9360 was produced.

[Comparative Example 1]
Using warp yarn 167 dtex / 36f (manufactured by NAN YA) and polyester weaving yarn 167 dtex / 36f (manufactured by NAN YA), plain weave (density: 145 warps / inch, 65 wefts) / Inch), a woven fabric having a cover factor of 2,575 and a total number of single yarns of 7,560.

[Comparative Example 2]
Plain warp yarn (density: warp 110 / inch, weft 50 / inch) using polyester black original yarn 84dtex / 36f (manufactured by NAN YA) as warp yarn and polyester black original yarn 84dtex / 36f (manufactured by NAN YA) as warp yarn. ), A woven fabric having a cover factor of 1391 and a total number of single yarns of 5760 was prepared.

[Comparative Example 3]
Plain warp yarn (density: warp 70 / inch, weft 40 / inch) using polyester black original yarn 330dtex / 72f (manufactured by NAN YA) as warp yarn and polyester black original yarn 330dtex / 72f (manufactured by NAN YA) as weft yarn. ), A woven fabric having a cover factor of 1896 and a total number of single yarns of 7920 was prepared.

[Comparative Example 4]
Plain warp yarn (density: warp 90 / inch, weft 65 / inch) using polyester black original yarn 330dtex / 72f (manufactured by NAN YA) as warp yarn and polyester black original yarn 330dtex / 72f (manufactured by NAN YA) as warp yarn. ), A fabric having a cover factor of 2671 and a total number of single yarns of 11160 was prepared.

[Comparative Example 5]
Plain weave (density: warp 127 / inch, weft 60 / inch) using polyester black original yarn 167dtex / 72f (manufactured by NAN YA) for warp yarn and polyester black original thread 167dtex / 72f (manufactured by NAN YA) for warp yarn ), A woven fabric having a cover factor of 2293 and a total number of single yarns of 13464 was prepared.

[Comparative Example 6]
Using warp yarn 167 dtex / 24f (manufactured by NAN YA) and polyester weaving yarn 167 dtex / 24f (manufactured by NAN YA), plain weave (density: warp 127 / inch, weft 55) / Inch), a woven fabric having a cover factor of 2231 and a total number of single yarns of 4368.

For each of the obtained woven fabrics of Examples 1 to 7 and Comparative Examples 1 to 6, each characteristic was measured and evaluated according to the measurement method described above. The results are shown in Table 1.

As shown in Table 1, all of the woven fabrics of Examples 1 to 7 had excellent light-shielding properties, friction durability, gravel sedimentation resistance and workability, and exhibited excellent characteristics as gravel-undersheets.

On the other hand, Comparative Example 1 had a low light blocking rate and insufficient light blocking properties. Comparative Example 2, which uses the same multifilament yarn as in Example 3 but has a low weave density, has low light shielding properties and insufficient gravel sedimentation resistance.

In Comparative Example 3 using the same multifilament yarn as in Example 7 but having a low woven density, the light shielding properties were insufficient. Conversely, Comparative Example 4 using the same multifilament yarn but having increased weave density has good light shielding properties, but has high bending resistance and high constant elongation load, that is, the fabric becomes stiff and the workability is insufficient. Met.

Further, Comparative Example 5 woven using a multifilament yarn having a low single yarn fineness had low bending resistance, insufficient gravel sedimentation resistance, and poor friction durability. On the contrary, Comparative Example 6 using a multifilament yarn having a high single yarn fineness had high bending resistance and constant elongation load, that is, the fabric became hard, the workability was poor, and the light shielding property was poor. .

Claims (5)

A gravel bottom sheet comprising a woven fabric using multifilament yarn for warp and weft yarns, the woven fabric having a cover factor of 2,000 or more, a bending resistance of 50 mm to 100 mm, a constant elongation load of 70 N to 300 N, And the sheet | seat under gravel whose shading rate is 95% or more. The gravel lower sheet according to claim 1, wherein the total number of single yarns of the warp yarn and the weft yarn within 2.54 cm square is 6,000 to 10,000. The gravel bottom sheet according to claim 1 or 2, wherein the fineness of the single yarn constituting the multifilament yarn is 2.3 dtex to 4.6 dtex. The gravel lower sheet according to any one of claims 1 to 3, wherein a total fineness of the multifilament yarn is 84 dtex to 330 dtex. The gravel bottom sheet according to any one of claims 1 to 4, wherein the multifilament yarn is black, gray, brown, green or blue.