NZ623676B2 - A layered sheet material - Google Patents

Abstract

laminated sheet material [10], and a geo-container [24] produced therefrom, suitable for use in alleviating erosion. The laminated sheet material [10] is characterized in comprising at least three layers, namely an entrapment layer [12] for trapping gravel, soil, sand or the like particles; a filtration layer [16] for allowing filtration of water and other moisture through the laminated sheet material [10]; and a reinforcement layer [14] between the entrapment and filtration layers [12, 16] for reinforcing the laminated sheet material [10]; increasing inter-layer peel strength between the entrapment and filtration layers [12, 16] and reducing elongation of the laminated sheet material [10]. The laminated sheet material [10] further includes bonding means [21] for bonding the material layers together. ration layer [16] for allowing filtration of water and other moisture through the laminated sheet material [10]; and a reinforcement layer [14] between the entrapment and filtration layers [12, 16] for reinforcing the laminated sheet material [10]; increasing inter-layer peel strength between the entrapment and filtration layers [12, 16] and reducing elongation of the laminated sheet material [10]. The laminated sheet material [10] further includes bonding means [21] for bonding the material layers together.

Description

A LAYERED SHEET MATERIAL INTRODUCTION The invention relates to an erosion prevention sheet material, and to products produced therefrom, for use in preventing, or at least alleviating, erosion, particularly in coastal, maritime, land and riverine shores, artificial reefs, dams, lakes, tailings storage facilities and the like.

BACKGROUND TO THE INVENTION Although erosion of soil and rock by processes such as wind and/or water flow is a natural process, human activities have dramatically increased the rate at which erosion is occurring globally. Excessive erosion causes problems such as desertification, decreases in agricultural productivity due to land degradation, sedimentation of waterways, and ecological collapse due to loss of the nutrient rich upper soil layers. Water and wind erosion are now the two primary causes of land degradation; combined, they are responsible for 84% of degraded acreage, making excessive erosion one of the most significant global environmental problems we face today.

One area of erosion with which the invention is specifically concerned relates to erosion of coastal, maritime, land and riverine shores, artificial reefs, dams, lakes, tailings storage facilities and the like. Bank erosion is the wearing away of the banks of a stream or river and occurs with continued water flow along a linear feature. By far the most erosion occurs during times of flood, when more and faster-moving water is available to carry a larger sediment load. In such processes, it is not the water alone that erodes: suspended abrasive particles, pebbles and boulders can also act erosively as they traverse a surface.

One prior art solution to alleviating the problem with this type of erosion concerns the use of a bi- layered sheet material, which may be wrapped around an embankment or sewn into geo- containers, which are strategically positioned to stabilize banks and slopes and to counter the effect of seepage, pore water pressure, and bank geometry on erosion of layered stream banks.

This bi-layered sheet material comprises two layers which are needled together – an outer entrapment layer, for trapping gravel, soil, sand or the like particles; and an inner filtration layer for allowing through-filtration of water and other moisture.

However, a number of shortcomings exist with the prior art bi-layered sheet material for erosion prevention. The outer entrapment layer comprises short, coarse fibers which are required for good abrasion characteristics. However, the aggressive environments in which this material is typically used causes stretching of the outer layer fibers, a resultant reduction in material strength and unwanted displacement of the material product made from this sheet material, such as geo- containers. Also, the inner and outer layers tend to pull apart, reducing peel strength in the material. In order to alleviate these problems, it is necessary to increase material thickness of the bi-layered sheet material to about 2 kg/m , but this makes it a heavy material to handle, transport and use.

A further problem is encountered at the seam lines of geo-containers. The yarn that is used in stitching the seams of the geo-containers during manufacture is exposed to and abraded over time by the natural elements, which results in failure of the geo-containers.

The applicant has identified a need for an improved erosion prevention sheet material which is lighter in weight than conventional bi-layered sheet material, but with improved inter-layered peel strength. The applicant has also identified a need to protect the seams of geo-containers or the like bags, which are produced from such sheet material, against the abrasive conditions in which these products are used.

SUMMARY OF THE INVENTION Definitions For purposes of interpreting this specification, the following words shall have the following meanings: Soil – includes, but is not limited to, soil native to coastal dunes, beaches, properties and riverine shores; and Geo-container – a bag which is designed and manufactured from high-strength fabrics, called geotextiles, which is typically filled with gravel, soil, sand, recycled material, treated material or a combination thereof, and which is used for stabilising banks and slopes, and for controlling erosion and/or pollution of soil so as to protect coastal, maritime, land and riverine shores, artificial reefs, dams, lakes, tailings storage facilities and the like from erosion caused by environmental factors. Geo-containers also find application in de-watering industrial and contaminated sludges generated by various industries, polluted waterways, ponds, dams and stilling basins.

According to a first aspect of the invention there is provided a laminated sheet material suitable for use in minimizing erosion and/or pollution of soil, the laminated sheet material being characterized in comprising at least three layers – an entrapment layer for trapping gravel, soil, sand or the like particles; a filtration layer for allowing through-filtration of water and other moisture through the laminated sheet material; and a reinforcement layer between the entrapment and filtration layers for reinforcing the laminated sheet material; increasing inter-layer peel strength between the entrapment and filtration layers, and reducing elongation of the laminated sheet material; the laminated sheet material further including bonding means for bonding the material layers together.

The entrapment layer may include either coarse synthetic fibre, or natural fibre, or a combination thereof. The entrapment layer may be abrasion resistant, UV resistant and vandal proof.

The filtration layer may include synthetic fibre, or natural fibre, or a combination thereof, the fibres of the filtration layer being relatively finer in comparison to the fibres constituting the entrapment layer. The filtration layer may be a woven fabric, a non-woven fabric, a knitted fabric, or any combination thereof.

The reinforcement layer may include high tenacity, low elongation filament yarns for maintaining the form of the laminated sheet material and products produced therefrom. The high tenacity, low elongation filament yarns may be derived from any one or more of the group including glass fibres, synthetic or natural continuous filaments, spun filaments, grids and/or scrims. In particular, the grids and/or scrims may be derived from one or more of the group including knitting, Crinette , woven and/or extruded origin. More particularly, the grids and/or scrims may be manufactured from any one or more of the group including cotton, flax filament yarns and the like.

The grids and/or scrims may also be manufactured from synthetic filament yarns.

The grids and/or scrims in the reinforcement layer may be coated with a polymeric substance.

The polymeric substance may be selected from the group including polyurethane, polyvinylchloride and synthetic rubber. The synthetic rubber may include natural and/or synthetic derived rubber.

The reinforcement layer further may include non-woven fleece fabric. The non-woven fleece fabric may be manufactured from natural fibres, synthetic fibres or a combination thereof. In one embodiment of the invention the non-woven fleece fabric may be manufactured from polyethylene terephthalate and/or other polymer materials.

The bonding means may be a chemical bonding agent or bonding adhesive, such as synthetic or resin glue. Alternatively, the bonding means may be fibres extending through the entrapment, reinforcement and filtration layers for consolidating the layers of the laminated sheet material.

The fibres may be needle-punched, sewn or stitched through the material layers at pre-defined or random intervals. In this embodiment of the invention the laminated sheet material may be heat treated to ensure thermal bonding between the fibres and the material layers. In particular, the fibres may thermally be bonded to the entrapment, reinforcement and filtration layers by means of hot air, open flame and/or an exothermic chemical process.

The laminated sheet material may have a cross-sectional thickness range of 5mm to 100mm and a mass range of 50g/m² to 5000g/m².

According to second aspect of the invention there is provided a method of manufacturing a laminated sheet material suitable for use in minimizing erosion and/or pollution of soil, the method comprising the steps of – providing an entrapment layer for trapping gravel, soil, sand or the like particles; providing a filtration layer for allowing through-filtration of water and other moisture through the laminated sheet material; providing a reinforcement layer between the entrapment and filtration layers for reinforcing the laminated sheet material; increasing inter-layer peel strength between the entrapment and filtration layers; and reducing elongation of the laminated sheet material and bonding the material layers together through a chemical bonding agent or bonding adhesive, such as synthetic or resin glue, or by needle-punching, sewing or stitching the material layers together with fibres extending through the entrapment, reinforcement and filtration layers.

If the material layers are needle-punched, sewn or stitched together, the laminated sheet material may be heat treated to ensure thermal bonding between the fibres and the material layers. In particular, the fibres may thermally be bonded to the entrapment, reinforcement and filtration layers by means of hot air, open flame and/or an exothermic chemical process.

The method may provide first connecting the reinforcement and filtration layers together, and then connecting the entrapment layer to the interconnected reinforcement and filtration layers.

The laminated sheet material of the invention may be shaped and dimensioned to be used as a ground cover, wrap-around envelope sheet and/or a geo-container. The invention extends to a ground cover, wrap-around envelope sheet and a geo-container produced from the laminated sheet material of the invention for preventing, or at least alleviating, erosion, particularly in coastal, maritime, land and riverine shores, artificial reefs, dams, lakes, tailings storage facilities and the like.

According to a third aspect of the invention there is provided a method of manufacturing a geo- container for use in minimising erosion, particularly in coastal, maritime, land and riverine shores, artificial reefs, dams, lakes, tailings storage facilities and the like, the method comprising the steps of – providing a laminated sheet material including an entrapment layer for trapping gravel, soil, sand or the like particles, and a filtration layer for allowing through-filtration of water and other moisture through the laminated sheet material; folding the laminated sheet material to form a bag with at least two layers of the laminated sheet material abutting each other to define a seam edge; sewing the abutting sheet material at the seam edge with at least two parallel rows of chain or lock stitch; followed by an overlock stitch enveloping the seam edge and two parallel rows of chain or lock stitch; introducing adhesive into the sewn seam edge to bond the abutting layers of sheet material; and filling the bag with filler material.

The laminated sheet material may be a laminated sheet material according to the invention.

The two parallel rows of chain or lock stitch may be located between 10mm and 20 mm from the seam edge, and may be located immediately adjacent each other.

The laminated sheet material may be sewn with a high strength polymeric yarn, including polyester, polypropylene, polyethylene and other synthetic yarns.

The geo-container may range in size from hand-filled, 40kg geo-containers, to hydraulically-filled, mega-geo-containers.

SPECIFIC EMBODIMENT OF THE INVENTION Without wishing to be bound by it, the invention will now further be described by way of non- limiting example only and with reference to the accompanying drawings in which – Figure 1 is a cross-sectional side view of laminated sheet material according to the invention; Figure 2 is another cross-sectional side view of the laminated sheet material of the invention; Figure 3 is one embodiment of a geo-container according to the invention, illustrating the sewn seam edge; Figure 4 is an enlarged sectional end view of the sewn seam edge of the geo-container of Figure 3; Figure 5 is a side elevation of the sewn seam edge of Figure 4; and Figure 6 illustrates the manner in which geo-containers according to the invention are stacked in use to minimise erosion, particularly in coastal, maritime, land and riverine shores, artificial reefs, dams, lakes, tailings storage facilities and the like.

A laminated sheet material according to the invention is designated by reference numeral [10].

The laminated sheet material [10] includes at least three layers, namely an entrapment layer [12] for trapping gravel, soil, sand or the like particles; a filtration layer [16] for allowing through- filtration of water and other moisture through the laminated sheet material [10]; and a reinforcement layer [14] between the entrapment and filtration layers [12, 16] for reinforcing the laminated sheet material [10] and increasing inter-layer peel strength and reducing elongation of the laminated sheet material [10].

The entrapment layer [12] includes either coarse synthetic fibre, or natural fibre, or a combination thereof [see 13]. The entrapment layer [12] is abrasion resistant, UV resistant and vandal proof.

The filtration layer [16] includes synthetic fibre, or natural fibre, or a combination thereof. The fibres of the filtration layer [16] are relatively finer in comparison to the fibres [13] that constitute the entrapment layer [12]. The filtration layer [16] may be a woven fabric, a non-woven fabric, a knitted fabric, or any combination thereof. Dewatering takes place through the filtration layer [16], which is completely permeable.

The reinforcement layer [14] may include high tenacity, low elongation filament yarns for maintaining the form of the laminated sheet material [10] and products produced therefrom. The high tenacity, low elongation filament yarns may be derived from glass fibres, synthetic or natural continuous filaments, spun filaments, grids and/or scrims. The grids and/or scrims may be derived from knitting, Crinette , woven and/or extruded origin. More particularly, the grids and/or scrims may be manufactured either from cotton, flax filament yarns and the like natural filament yarns, or from synthetic filament yarns. Figures 1 and 2 depict a woven or knitted layer with a warp [17] and a weft [19].

The reinforcement layer [14] further may include non-woven fleece fabric [23]. The non-woven fleece fabric [23] may be manufactured from natural fibres, synthetic fibres or a combination thereof. In one embodiment of the invention the non-woven fleece fabric [23] may be manufactured from polyethylene terephthalate and/or other polymer materials.

The bonding means may be a chemical bonding agent or bonding adhesive, such as synthetic or resin glue. Alternatively, the bonding means may be fibres [21] extending through the entrapment, reinforcement and filtration layers [12, 14, 16] for consolidating the layers of the laminated sheet material [10]. The fibres [21] may be needle-punched, sewn or stitched through the material layers at pre-defined or random intervals. In this embodiment of the invention the laminated sheet material [10] may be heat treated to ensure thermal bonding between the fibres [21] and the material layers [12, 14, 16]. In particular, the fibres may thermally be bonded to the entrapment, reinforcement and filtration layers [12, 14, 16] by means of hot air, open flame and/or an exothermic chemical process. In Figures 1 and 2, bonding [18] of the fibres [21] occurs at pre- defined or random intervals.

Those who are engaged in the art will appreciate that consolidation of the laminated sheet material [10] through bonding together of the material layers will minimize delamination of the laminated sheets, and loss, unravelling and pilling of fibre.

The laminated sheet material [10] may have a cross-sectional thickness range of 5mm to 100mm and a mass range of 50g/m² to 5000g/m².

According to second aspect of the invention there is provided a method of manufacturing a laminated sheet material [10] suitable for use in minimizing erosion and/or pollution of soil, the method comprising the steps of – providing an entrapment layer [12] for trapping gravel, soil, sand or the like particles; providing a filtration layer [16] for allowing through-filtration of water and other moisture through the laminated sheet material [10]; providing a reinforcement layer [14] between the entrapment and filtration layers [12, 16] for reinforcing the laminated sheet material [10] and increasing inter-layer peel strength between the entrapment and filtration layers [12, 16]; and bonding the material layers [12, 14, 16] together through a chemical bonding agent or bonding adhesive, such as synthetic or resin glue, or by needle-punching, sewing or stitching the material layers [12, 14, 16] together with fibres [13, 21] extending through the entrapment, reinforcement and filtration layers [12, 14, 16].

If the material layers [12, 14, 16] are needle-punched, sewn or stitched together, the laminated sheet material [10] may be heat treated to ensure thermal bonding between the fibres [21] and the material layers. In particular, the fibres [21] may thermally be bonded to the entrapment, reinforcement and filtration layer [12, 14, 16] by means of hot air, open flame and/or an exothermic chemical process.

The method may provide first connecting the reinforcement and filtration layers [14, 16] together, and then connecting the entrapment layer [12] to the interconnected reinforcement and filtration layers [14, 16].

The laminated sheet material [10] of the invention may be shaped and dimensioned to be used as a ground cover, wrap-around envelope sheet and/or a geo-container. The invention extends to a ground cover, wrap-around envelope sheet and a geo-container produced from the laminated sheet material [10] of the invention for preventing, or at least alleviating, erosion, particularly in coastal, maritime, land and riverine shores, artificial reefs, dams, lakes, tailings storage facilities and the like.

According to a third aspect of the invention there is provided a method of manufacturing a geo- container [24] for use in minimising erosion, particularly in coastal, maritime, land and riverine shores, artificial reefs, dams, lakes, tailings storage facilities and the like, the method comprising the steps of – providing a laminated sheet material [10] including an entrapment layer [12] for trapping gravel, soil, sand or the like particles, and a filtration layer [16] for allowing through-filtration of water and other moisture through the laminated sheet material [10]; folding the laminated sheet material [10] to form a bag with at least two layers of the laminated sheet material [10] abutting each other to define a seam edge [26]; sewing the abutting sheet material [10] at the seam edge [26] with at least two parallel rows of chain or lock stitch [28]; followed by an overlock stitch [30] enveloping the seam edge [26] and two parallel rows of chain or lock stitch [28]; introducing adhesive [32] into the sewn seam edge [26] to bond the abutting layers of sheet material [10]; and filling the bag [24] with filler material.

The laminated sheet material [10] may be a laminated sheet material [10] according to the invention.

The two parallel rows of chain or lock stitch [28] may be located between 10mm and 20 mm from the seam edge [26], and may be located immediately adjacent each other.

The laminated sheet material [10] may be sewn with a high strength polymeric yarn, including polyester, polypropylene, polyethylene and other synthetic yarns.

The geo-container [24] may range in size from hand-filled, 40kg geo-containers [24], to hydraulically-filled, mega-geo-containers [24].

It will be appreciated that other embodiments of the invention may be possible without departing from the spirit or scope or scope of the invention as defined in the claims.

Claims (23)

1. A laminated sheet material [10] suitable for use in minimizing erosion and/or pollution of soil, the laminated sheet material [10] being characterized in comprising at least three 5 layers – an entrapment layer [12] for trapping particles, including gravel particles, soil particles, or sand particles; a filtration layer [16] for allowing through-filtration of moisture, including water, through the laminated sheet material [10]; and 10 a reinforcement layer [14] between the entrapment and filtration layers [12, 16] for reinforcing the laminated sheet material [10]; increasing inter-layer peel strength between the entrapment and filtration layers [12, 16]; and reducing elongation of the laminated sheet material [10]; the laminated sheet material [10] further including bonding means [21] for bonding 15 the material layers together.

2. The laminated sheet material [10] according to claim 1 wherein the entrapment layer [12] includes either coarse synthetic fibre, or natural fibre, or a combination thereof [13]. 20

3. The laminated sheet material [10] according to claim 1 or claim 2 wherein the entrapment layer [12] is abrasion resistant, UV resistant and vandal proof.

4. The laminated sheet material [10] according to claim 2 wherein the filtration layer [16] includes synthetic fibre, or natural fibre, or a combination thereof, the fibres of the filtration 25 layer [16] being relatively finer in comparison to the fibres [13] constituting the entrapment layer [12].

5. The laminated sheet material [10] according to claim 1 or claim 4 wherein the filtration layer [16] is a woven fabric, a non-woven fabric, a knitted fabric, or any combination 30 thereof.

6. The laminated sheet material [10] according to claim 1 wherein the reinforcement layer includes high tenacity, low elongation filament yarns [21] for maintaining the form of the laminated sheet material [10] and products produced therefrom.

7. The laminated sheet material [10] according to claim 6 wherein the high tenacity, low elongation filament yarns [21] are derived from any one or more of the group including glass fibre, synthetic or natural continuous filaments, spun filaments, grids and/or scrims.

8. The laminated sheet material [10] according to claim 7 wherein the grids and/or scrims are derived from one or more of the group including knitting, woven and/or extruded origin. 5

9. The laminated sheet material [10] according to claim 7 or claim 8 wherein the grids and/or scrims are manufactured from any one or more of the group including cotton, flax filament and yarns.

10. The laminated sheet material [10] according to claim 7 or claim 8 wherein the grids and/or 10 scrims are manufactured from synthetic filament yarns.

11. The laminated sheet material [10] according to claim 1 wherein the reinforcement layer includes non-woven fleece fabric [23]. 15

12. The laminated sheet material [10] according to claim 11 wherein the non-woven fleece fabric [23] is manufactured from natural fibres, synthetic fibres or a combination thereof.

13. The laminated sheet material [10] according to claim 12 wherein the non-woven fleece fabric [23] is manufactured from polyethylene terephthalate and/or other polymer 20 materials.

14. The laminated sheet material [10] according to claim 1 wherein the bonding means is a chemical bonding agent or bonding adhesive, such as synthetic or resin glue inter- connecting the entrapment, reinforcement and filtration layers [12, 14, 16] for 25 consolidating the layers of the laminated sheet material [10].

15. The laminated sheet material [10] according to claim 1 wherein the bonding means is fibres [21] extending through the entrapment, reinforcement and filtration layers [12, 14, 16] for consolidating the layers of the laminated sheet material [10].

16. The laminated sheet material [10] according to claim 15 wherein the fibres [21] are needle-punched, sewn or stitched through the material layers at pre-defined or random intervals. 35

17. The laminated sheet material [10] according to claim 15 wherein the laminated sheet material [10] is heat treated to ensure thermal bonding between the fibres [21] and the material layers [12, 14, 16].

18. The laminated sheet material [10] according to claim 17 wherein the fibres [21] are thermally bonded to the entrapment, reinforcement and filtration layers [12, 14, 16] by means of hot air, open flame and/or an exothermic chemical process. 5

19. The laminated sheet material [10] according to claim 1 wherein the material has a cross- sectional thickness range of 5mm to 100mm and a mass range of 50g/m² to 5000g/m².

20. A method of manufacturing a laminated sheet material [10] suitable for use in minimizing erosion and/or pollution of soil, the method comprising the steps of – 10 providing an entrapment layer [12] for trapping particles, including gravel particles, soil particles, or sand particles; providing a filtration layer [16] for allowing through-filtration of water and other moisture through the laminated sheet material [10]; providing a reinforcement layer [14] between the entrapment and filtration layers 15 [12, 16] for reinforcing the laminated sheet material [10]; increasing inter-layer peel strength between the entrapment and filtration layers [12, 16] and reducing elongation of the laminated sheet material [10]; and bonding the material layers [12, 14, 16] together through a chemical bonding agent or bonding adhesive, such as synthetic or resin glue; or by needle-punching, sewing or 20 stitching the material layers together with fibres [21] extending through the entrapment, reinforcement and filtration layers [12, 14, 16].

21. The method of manufacturing a laminated sheet material [10] according to claim 20 wherein, if the material layers are needle-punched, sewn or stitched together, the 25 laminated sheet material [10] is heat treated to ensure thermal bonding between the fibres and the material layers [12, 14, 16].

22. The method of manufacturing a laminated sheet material [10] according to claim 21 wherein the fibres [21] are thermally bonded to the entrapment, reinforcement and filtration 30 layers [12, 14, 16] by means of hot air, open flame and/or an exothermic chemical process.

23. The method of manufacturing a laminated sheet material [10] according to claim 20 wherein the method provides first connecting the reinforcement and filtration layer [14, 16] together, and then connecting the entrapment layer [12] to the interconnected 35 reinforcement and filtration layers [14, 16].