Self healing salt water barrier

The present invention relates to methods and articles useful as watertight membranes for providing a watertight surface before penetration of a salt containing water with high conductivity, e.g. bay water, ground water, swamp water, brackish water, ocean water, mine waste water, for example when forming watertight areas of structures exposed to high conductivity waters, such as ponds, areas containing harmful or toxic waste, underground surfaces foundation and the like. In particular, the present invention relates to salt water resistant articles formed by entrapping a partially crosslinked polyacrylamide / partially neutralized polyacrylic acid copolymer in a mat. Alternatively, the copolymer can be extruded into a non-woven mat after the mat has been made, or it can be made directly into the structure by polymerization or other methods. BACKGROUND OF THE INVENTION AND BACKGROUND ART [0002] Various polymers, swelling clays and multilayered articles were applied to the soil surface to form a watertight layer to prevent water penetration and / or hazardous or toxic materials into the ground, and to obtain ponds for holding sewage, swimming pools and other areas for water collection. Water-swellable clays, such as bentonite, are applied directly to the soil surface and compacted in situ, as disclosed in an earlier patent of the present assignee US 3,986,365. In addition, many different multi-layered products containing water-swellable clay such as bentonite sodium, made by attaching water-swellable clay to the main internal surfaces of flexible sheet materials, e.g. Clem, US Patent No. 4 501 788, to be applied to the soil surface in contact or overlap so that it adheres to multi-layered products. Examples of other flexible sheet materials containing adhesive bonded water-swellable clays are found in the following US Patent Nos. 4,467,015, Clem; 4,693,923, McGroarty et al .; 4,656,062, Harriett; and 4,787,780, Harriett.

[0003] Published British patent application GB 2 202 185A discloses a layer of water-swellable bentonite between layers of flexible textile material which was needle-punched in a needle loom, connecting the upper and lower layers together, at least one of the fabric layers being a non-woven textile material .

[0004] Another waterproof barrier disclosed in US Patent No. 4,344,722, Blais, is made in the field by applying a first elastic, water-permeable layer of textile material, covering it with a thick layer of water-swellable clay material and applying on top of this layer the flexible, water-permeable textile material itself. Other patents disclosing the use of water barrier layers to protect soil surface include British Patent 1 059 363; British Patent Specification 1 029 513 and British Patent Specification 1 129 840.

[0005] German Patent DE 37 04 503 C2 discloses an article having two layers of fabric comprising one non-woven material surrounding a layer of bentonite clay, the two layers of fabric being needled together. In US Patent No. 4,565,468, Crawford,

EP2 217 439 B1 discloses an article comprising two layers of textile material surrounding a layer of bentonite clay, the two layers of material being quilted together in a pattern forming quadrilateral compartments.

[0006] Although the articles described in the above-mentioned patents effectively provide watertightness against penetration of relatively unpolluted water, they are not able to prevent penetration of salt-containing water (e.g. NaCl), such as ocean water. US Patent No. 3,389,166, which is hereby incorporated by reference, describes the introduction of water-swellable clay into a mat during fiber laying to form a mat. [0007] It has surprisingly been found that a partially crosslinked copolymer of acrylamide / partially neutralized polyacrylic acid, preferably a copolymer of acrylamide / potassium acrylate or sodium acrylate / acrylic acid (CAS # 312-12-13-2), e.g. STOCKOSORB or STOCKOSORB S, from Stockhausen , Inc., Greensboro, NC, will provide watertightness against penetration of water with high conductivity. The articles described herein are most useful for providing a water barrier against polyvalent ions with a conductivity of at least 1 mS / cm, preferably at least 10 mS / cm, more preferably at least 30 mS / cm, even more preferably even at least 40 mS / cm, and most preferably at least 50 mS / cm.

[0008] Superabsorbent polymers ("SAP") have been produced since the 1970s for use in many products including, but not limited to, hygiene products such as disposable diapers, diaper pants, women's hygiene products, and urinary incontinence devices, agricultural and horticultural products as well as industrial and environmental absorbents. SAP is primarily used to increase or increase the product's water absorption.

[0009] SAP is made from different ingredients in different ways. For example, SAP is often made of monomers such as acrylamide, acrylic acid and acrylate, which are particularly useful for use in hygiene products.

[0010] Alternatively, swelling clays, such as sodium smectite clays, e.g. sodium bentonite, can be used to make the product absorb water. In terms of costs, the cost of swelling clays appears to be minimal compared to the chemical monomers described above. In addition, swellable clays are relatively stable compared to chemical monomers and do not degrade. However, the water absorption capacity of swelling clays is much smaller than that of SAP and, like the partially crosslinked copolymers of SAP partially neutralized acrylic acid, sodium smectites do not show sufficient free swelling when in contact with salt water with high specific conductivity to act as a salt water barrier .

[0011] Certain products contain both SAP and swellable clay, such as those described in US Patent No. 6,610,780 and in US Patent of this Assignee No. 6 783 802, which is hereby incorporated by reference. However, neither SAP nor water-swellable clays are able to provide a watertight surface against penetration of contaminated water with high conductivity, such as ocean water.

[0012] It is well known that montmorillonite clays are hydrated and swell in fresh water, but swelling is generally inhibited in salt contaminated water. Salt-contaminated water is often found in environments where bentonite clays are used, where bentonite is used successfully because of its swelling ability, for example, as an additive to clay muds

Boreholes to seal gaps in earth formations surrounding the borehole to prevent loss of drilling mud; and in sealing ponds and landfills. In contact with salt-contaminated water, the swelling capacity and stability of ordinary montmorillonite clays strongly decreases, which necessitates the use of much larger amounts of clay to achieve the degree of swelling required for sealing purposes. In some cases, paligorskite clays are used instead of montmorillonite clays because of their better dispersibility in salt water, as disclosed in US Patent No. 4,202,413.

[0013] In the past, modified bentonite clays with a swelling capacity substantially less inhibited in salt water have been developed by the assignee. Examples of such modified bentonites and polymer-treated bentonites are disclosed in US Patent Nos. 3,949,560,

021 402, 4 048 373 and 4 103 499, Clem.

[0014] Patent US 4,634,538 discloses that one or more gums, such as xanthan gum, can be added to water swellable clay to improve its free swelling when hydrated with salt contaminated water. In the patent of this assignee US no

578 219 describes the impregnation of a dry, water-swellable clay with an aqueous solution of a water-soluble polymer, followed by subsequent drying, to improve the clay's ability to absorb contaminated water.

[0015] Partially crosslinked copolymers of acrylamide / sodium or potassium acrylate / acrylic acid were used to retain water and nutrients for plants in agriculture, by mixing copolymers in soil to bring into contact with plant roots, and as a source of water and nutrients, but it has not been established whether they exhibit sufficient free swelling in contact with water contaminated with salt (high conductivity) to ensure water tightness of surfaces in contact with contaminated water, as described in US Patent Publication No. 2007-0044528-awl and US Patent No. 5,317,834.

SUMMARY [0016] The articles and methods described herein are based on the discovery that superabsorbent polymers of the agricultural grade, partially crosslinked (water insoluble) copolymers of acrylamide / partially neutralized acrylic acid, especially potassium and / or sodium acrylate, show unique and unexpected swelling free in contact with water with high conductivity or contaminated water containing multivalent ions. All products described herein contain a partially crosslinked acrylamide / acrylate / acrylic acid copolymer and are used to provide water tightness for salt-containing water with high specific conductivity. In particular, the partially crosslinked acrylamide / acrylate / acrylic acid copolymers described herein, in accordance with a preferred embodiment of the present invention, are incorporated into a sheet or roller as watertight geotextile products; or introduced into formable putty-type products to ensure watertightness of cement joints and the like (see US Patent No. 4,539,926, which is hereby incorporated by reference) by replacing with the SAP species described herein for use in agriculture, bentonite clay according to patent 4,539,926. The geotextile products described herein in the form of a sheet or roller are self-sealing (they will seal incisions, cracks and crevices caused in adjacent water barrier sheets or films during their installation or sweat) and are particularly effective in sealing seams between two water barrier substrates, for example.

EP2 217 439 B1 between concrete sections and between adjacent geocomposite liners in contact with salt water with high conductivity.

[0017] In the geocomposite articles of the invention, partially crosslinked acrylamide / acrylate / acrylic acid copolymers are included as a protective layer under a separate water barrier sheet material or membrane layer.

[0018] Therefore, in one aspect of the articles and method described herein, there is provided an acrylamide / acrylate / acrylic acid copolymer with sufficient free swelling in contact with water of high specific conductivity, such that the copolymer can provide a barrier against leakage of contaminated water.

[0019] Another aspect of the articles and methods described herein is to provide multilayer geocomposite articles comprising a polymer barrier layer, a fabric or nonwoven layer, and an intermediate layer of partially crosslinked acrylamide / acrylate / acrylic acid copolymer with sufficient free swelling in contact with water with high conductivity so that if a crack or break occurs in the polymer barrier layer, the closed copolymer will swell sufficiently in contact with salt water to fill the crack or rupture to seal the crack or rupture and prevent further leakage of salt water.

[0020] The above and other aspects and advantages will become apparent from the following detailed description in connection with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS [0021] FIG. 1 is a graph showing the volume of free swelling (2 grams of material in excess of aqueous salt solution) of partially cross-linked acrylamide / acrylate / acrylic acid copolymers in aqueous 1.0% NaCl and 4.5% sea salt compared to the standard, partially cross-linked SAP acrylate copolymer / acrylic acid (Favor SXM 880) and water-swellable clay, sodium bentonite (SPV);

[0022] FIG. 2 and 3 schematically show the device and methods of manufacture used to obtain geocomposite products useful as a salt water barrier in accordance with the present invention;

[0023] FIG. 2A, 2B and 2C are partial views from the side of various watertight geocomposite articles manufactured in accordance with various embodiments of the present invention;

[0024] FIG. 4 is a perspective view of the vertically oriented geocomposite article described herein in the vicinity of the sea / soil interface.

[0025] FIG. 5A and 5B schematically depict geocomposite products for testing with or without 1-inch gaps that were tested under the pressure exerted by a 4-meter salt water column to compare salt water barrier properties of products containing and not containing partially cross-linked acrylamide / acrylate copolymer acrylic acid, the results of these tests being shown in the graphs of FIG. 6 and 7; and [0026] FIG. 6 and 7 are graphs showing that the geocomposite products described herein, containing a 1-inch gap through, will provide a copolymer that ensures gap sealing by a swelling copolymer under the action of a 4-meter high salt conductivity salt water column.

EP2 217 439 B1

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0027] The present invention can be more easily understood by reference to the following detailed description of the invention and examples herein. It should be understood that the present invention is not limited to the specific components, articles, methods and / or conditions described, as these may of course vary. It should also be understood that the terminology used herein is only for the purpose of describing specific embodiments and cannot be considered as limiting.

[0028] Ranges may be given herein as from "about" or "approximately" one specific value and / or to "about" or "approximately" another specific value. When such a range is given, another embodiment includes a range from one specific value and / or to another specific value. Similarly, when the values ​​are expressed as approximate, by using the word "about," previously it should be understood that the particular value constitutes another embodiment.

[0029] Conductivity is a measure of the level of ion concentration in a solution. The more salts, acids or bases are dissociated, the greater the conductivity of the solution. In water or wastewater, it is mainly a matter of dissolved salt ions and therefore the conductivity is an indicator of the salt wastewater load. The conductivity value is usually expressed in S / cm (or mS / cm) and is the product of the conductance of the tested solution and the geometric factor of the measuring cell. For the purposes of this invention, waters with high conductivity are defined as waters with conductivity above 1 mS / cm. Conductivity can be measured using many commercially available measuring instruments, such as the Waterproof PC 300 hand-held meter manufactured by Eutech Instruments / Oakton Instruments.

[0030] In a preferred embodiment, the partially crosslinked acrylamide / acrylate / acrylic acid copolymer is introduced as a layer between the water barrier sheet or barrier film layer, preferably a polymeric sheet material or membrane layer and a fabric layer in the form of a woven or nonwoven geotextile sheet material. A layer of polymeric sheet material should be placed in contact with water of high conductivity, and the copolymer is placed adjacent to the layer of polymeric sheet material between the membrane and fabric layers so that it acts as a protective layer, preventing the flow of water of high conductivity through the product when the layer of the polymer sheet material is damaged or a crack or hole appears in it during installation or during use. Alternatively, the copolymer can be introduced into gaps in the geotextile fabric layer to form a fabric / copolymer composite layer that serves as a protective layer attached to the membrane layer to prevent high conductivity water from flowing through the product when the polymer sheet material layer is damaged or appears in it a crack or hole during installation or during use.

[0031] Partially cross-linked acrylamide / partially neutralized acrylic acid copolymers, e.g. STOCKOSORBT, have been found^M and / or STOCKOSORB S ™, show significant free swelling when in contact with solutions with high specific conductivity. Examples of tested aqueous solutions with high specific conductivity are 1% NaCl (18 mS / cm specific conductivity) and synthetic sea water (4.5% sea salt; 53.2 mS / cm specific conductivity). Partially cross-linked acrylamide / partially neutralized acrylic acid copolymers show significant free swelling when in contact with aqueous solutions contaminated with any of Na +, Ca cations⁺⁺, Mg +, Al⁺⁺⁺ or theirs

EP 2 217 439 B1 combination, and other polyvalent cations, in combination with anions that are commonly found in seawater and other wastewater. To achieve the full advantage of the geocomposite products and methods described herein, the partially crosslinked acrylamide / acrylate / acrylic acid copolymers used in the geocomposite products should exhibit free swelling in water with 4.5% salt of at least 35 ml per 2 grams of copolymer, preferably at least about 40 ml / 2 grams, more preferably at least about 50 ml / 2 grams. Free swelling is determined by pouring 2 grams of powdered copolymer into a 100 ml measuring cylinder and filling the cylinder to 100 ml with water with 4.5% salt. The volume of copolymer that has settled at the bottom of the measuring cylinder is measured and it is a free swelling.

[0032] In a preferred embodiment, multilayered articles are described herein which constitute geocomposite mats as a salt water barrier, and a method for their preparation. In a preferred embodiment, the geocomposite mat comprises a pre-formed woven or non-woven geotextile textile material, about 0.5 mm to about 200 mm thick, preferably about 1 mm to about 100 mm thick, comprising a layer of powdered or granulated partially crosslinked acrylamide copolymer / partially neutralized acrylic acid . at least in the upper part of its thickness over its entire main surface or containing a separate layer of geotextile sheet or textile material. In a preferred embodiment, the powdered or granular copolymer is at least partially introduced into the pores of the textile material or geotextile mat so as to surround the upper fibers, e.g. by vacuum suction, as a result of vibration during the deposition of the copolymer, to allow the flow of powdered or granular copolymer as a result of gravity and vibrational forces to the pores in the sheet or geotextile mat, or simply by choosing the size of its particles to fit in the contact pores a woven or non-woven surface (preferably non-woven) of a textile material or geotextile mat.

[0033] In a preferred embodiment of the liquid-impermeable cover sheet (membrane layer) is adhered to the upper main surface of the geotextile textile or mat containing the copolymer to prevent the powdered or granular copolymer from escaping from the geotextile sheet or mat during transport and installation, and provide a basic water-impermeable product layer. The edges of the geotextile sheet or mat containing the copolymer can optionally be sealed, for example by using an upper, water-impermeable cover sheet with dimensions slightly larger than the dimensions of the geotextile sheet or mat and gluing or otherwise fixing additional covering sheet material to the edges of the geotextile containing copolymer, for example by welding them. Another variant of edge sealing involves stitching, needling and ultrasonic welding of the cover sheet with the edge of the geotextile sheet or mat, or by using a separate edge covering material that can be glued, welded or ultrasonically welded to a water-impermeable cover sheet and / or to a geotextile sheet or mat . The edge sealing materials are preferably liquid impermeable.

[0034] In addition to the partially crosslinked acrylamide / partially neutralized acrylic acid copolymer layer, powdered or granular materials can be mixed with the copolymer or can be applied as a separate layer. Additional powdered or granular materials include water-swellable smectite clay, organophilic clay, activated carbon, fine coke, zero valent iron, apatite, zeolite, peat moss, polymeric ion exchange resins, polymeric adsorbents and

Mixtures thereof. Preferably, the copolymer is placed adjacent to the water-impermeable barrier layer in the form of a sheet or foil and may also contain other materials mixed with it in an amount of up to about 80% by weight of the mixture.

[0035] The method of manufacture allows the production of a geocomposite article that contains a partially crosslinked acrylamide / acrylate / acrylic acid copolymer that is structurally attached without significant lateral movement and contains an intumescent material or as a separate layer between the impermeable sheet and the geotextile, evenly distributed in a geotextile or spread in a gradient manner in a geocomposite article. A multilayer geocomposite article can be made to obtain a flexible or rigid geocomposite article, with the possibility of producing various modified geocomposite articles that contain as a salt water barrier a swelling copolymer in addition to zeolite or organophilic clay, with or without water-absorbing material in the form of sodium smectite; using a layer (s) of the liquid-impermeable film or material sheet not only above one but above both major surfaces of the geocomposite article to keep the granulated or powdered copolymer material in place in the geotextile sheet or mat; applying solid or liquid materials or adhesive compositions to adhere the main lower surface of the barrier layer to the copolymer or to the copolymer containing geotextile sheet material for full retention. The materials can be mechanically bound (sewing, stitching or gluing), chemically or physically (e.g. melting or similar). The structure can be stiffened or reinforced by inserting inside or onto a geocomposite article during the manufacture of one or more stiffening materials, such as a perforated fiberglass sheet; rope; cardboard; relatively rigid, liquid-permeable corrugated materials, e.g. corrugated board and the like, at certain points on surfaces or between the upper and lower main surfaces of a geocomposite article, to provide varying degrees of flexibility or stiffness; the ability to produce geocomposite products without the need for a consolidation phase; and obtaining geotextile products of various sizes, shapes and weights in order to take advantage of each of them.

[0036] The copolymers described herein are slightly crosslinked, i.e. their crosslinking density is below about 20%, preferably below about 10%, and most preferably about 0.01% to about 7%. The crosslinker is most preferably used in an amount of less than about 7% by weight, and usually about 0.1% by weight, based on the total weight of the monomers. Examples of cross-linked polyvinyl monomers include, but are not limited to, di-, tri- or other multifunctional acrylic, methacrylic, vinylether, or acrylamide functional groups that are well known in the art.

[0037] The relative amounts of acrylamide, acrylate and acrylic acid in the copolymers providing salt water resistance described herein can vary widely from about 1 mol% to about 99 mol% of each of the components in the copolymer. The best results in achieving perfect free swelling in water with high specific conductivity are obtained when the acrylamide is about 5% to about 90 mole% of the copolymer, preferably about 15% to about 60 mole%; sodium and / or potassium acrylate constitutes about 2% to about 50 mole% of the copolymer, preferably about 5% to about 25 mole% of the copolymer; and acrylic acid constitutes about 2% to about 50% of the copolymer, preferably about 1% to about 10 mole% of the copolymer. Other material compositions that provide a free swell of more than about 35 ml / 2 grams of material in water with 4.5% sea salt are within the scope of the present invention. IN

Other monomers, including acrylic and methacrylic esters and acids, and substituted acrylamide and methacrylamides may be present in the copolymer, provided that other monomers do not impair the copolymer's ability to absorb water with high conductivity.

[0038] As shown in FIG. 2 and 3, a method and apparatus is illustrated, comprising several variant features, each of which can be used alone or in combination with any other features to produce a product containing only partially crosslinked acrylamide / acrylate / acrylic acid as a powdered or granular material, or a variety of granular or powdered material, including a copolymer with or without various reinforcing materials and / or coating materials applied to one or both outer surfaces of the manufactured article to give different characteristics or properties to finished geocomposite barrier 10 salt water products, as will be described in more detail below. The device typically includes a conveyor belt 17 that moves continuously around a pair of rollers 18 and 20, at least one of which is driven by the motor at a desired speed; and one or more powdered or granular material metering devices, generally designated by reference numerals 22 and 24.

[0039] Layer 14 of the liquid-impermeable sheet material used to provide the base salt barrier sheet is applied to the upper main surface of the pre-formed sheet or geotextile mat 15 after loading the sheet or geotextile mat 15 with a partially cross-linked acrylamide / acrylate / acid copolymer acrylic 16 from one or both of the 22 and / or 24 metering devices. In one embodiment, the powdered or granular copolymer 16 penetrates into the geotextile sheet or mat 15 by vibration of the geotextile 15 by means of a vibrator 140. Alternatively, a vacuum can be applied under the geotextile sheet or mat 15. Alternatively, the copolymer 16 penetrates minimally into the upper surface of the geotextile sheet or mats 15 to form a separate copolymer layer sandwiched between a geotextile sheet or mat 15 and a base waterproof barrier layer 14.

[0040] Additional granulated or powdered materials may be applied to the geotextile sheet or mat 15 from feeding lines 22 or 24 to obtain the concentration of copolymer 16 on one or more surfaces, or to apply other powdered or granular material, prior to application of the water-impermeable layers cover 14. The base barrier layer 14 is preferably adhered to the upper main surface of the copolymer containing geotextile sheet or mat 15 using a water insoluble adhesive applied from the adhesive supply tank 34. Other non-limiting methods for incorporating the copolymer into the composite structure can be envisaged. Alternative methods could include: coating or spraying the paste or copolymer dispersion onto a sheet by extrusion coating or roller coating; pre-assembling the copolymer / fabric composite for subsequent connection to the water-impermeable layer to form the final composite; or other ways to achieve the desired structure.

[0041] In FIG. 2A shows a geotextile sheet or mat 15 filled only on the upper main surface with powdered or granular copolymer material 16. In FIG. 2B shows a geotextile sheet or mat 15 filled with copolymer 16 fed through a geotextile sheet or mat 15. In FIG. 2C shows partial deposition of copolymer 16 in the upper surface of a geotextile (preferably non-woven) sheet or mat 15, with a separate intermediate copolymer layer and adhesive

An upper, basic, water-impermeable layer of sheet material 14. Other layers of material could be envisaged to help improve the mechanical strength of the composite, facilitate the retention of the copolymer in the structure, or improve the bonding of the various layers of the structure.

[0042] With reference to FIG. 3, there is shown a schematic diagram of one method for loading a pre-formed very fluffy geotextile mat 115 with a powdered or granular copolymer in the dry state. The dry material dispensing device, generally designated by reference number 100, is useful for depositing a partially crosslinked acrylamide / acrylate / acrylic acid copolymer, with or without other powdered or granular materials, such as organophilic clay or other materials, from the receiving hopper 102. The screw conveyor 104 is located at the bottom end of the discharge hopper 102 and in the flow enabling connection to it, forcing the copolymer material through the conduit 106 to the inlet 108 of the elevator 110. The copolymer is unloaded from the elevator 110 through the outlet outlet 112 of the elevator, via conduit 114 to the receiving hopper dump truck 116. A pair of screw conveyors 118 and 120 connected in a fluid manner to the bottom of the hopper 116 pumps the copolymer to one, two or three feeding mechanisms, generally designated by reference numerals 122, 124 and 126, to feed the copolymer in a regulated manner into one, two or three continuously feeding conveyor belts 128, 130 and 132 arranged successively above the longitudinal product conveyor belt 134.

[0043] The copolymer is usually applied to the geotextile sheet or mat 115 in an amount of about 0.1 ounces to 3 pounds of powdered or granulated copolymer per square foot of the main surface area of ​​the finished product, preferably about 0.1 ounce to about 5 pounds of powdered or granulated copolymer per square foot of the main surface of the finished product. According to one embodiment, a source of liquid impermeable flexible sheet material 136 in the form of a coil 138 can be positioned above the continuous product conveyor belt 134 to ensure continuous feeding of the liquid impermeable flexible material sheet to the upper surface of the product conveyor belt 134. On the upper surface of the sheet material 136 from the roll 138, liquid adhesive can be sprayed from the adhesive tank 139 to glue the sheet material to the underside of the geotextile sheet or mat 115, after which the powdered or granular copolymer is deposited on the geotextile sheet or mat 115 of one, two or mat all three feeding conveyor belts 128, 130 and 132. Any of one, two or all three conveyor feed belts 228, 230 and 232 can be used to feed the same or different powdered or granular materials into parts or the entire thickness of the geotextile sheet or mat 115. The vibrating apparatus 140 can be connected to the product conveyor belt immediately below the supplying conveyor belts 128, 130 and 132 to induce vibration of powdered or granular pollutant / reagent materials in a geotextile sheet or mat 115.

[0044] The powdered or granular copolymer is deposited along the entire width of the geotextile sheet or mat 115, in the form of particles falling from feeders 122, 124 and / or 126. In this way, the fibrous mat 115 can be filled with the copolymer over the entire thickness or in any part of the thickness . Dust collecting suction devices 144, 146 and 148 may be arranged near each of the continuous feeds

EP2 217 439 B1 to conveyor belts 128, 130 and 132 to clean the air of fine particles emitted by the feeding mechanisms 122, 124 and 126 and to return the particles to the dust collector 167 for their removal and / or to return to the receiving hopper 102 via line 149. A second flexible, water-impermeable sheet material 150, from coil 151, is placed on the side behind the copolymer feeding mechanisms 122, 124 and 126 and above the product conveyor belt 134. The second flexible sheet material 150 is introduced by means of driven roll 152, driven rollers 154 and 156 and winding rollers 158 and 160 to place the flexible, water-impermeable sheet material 150 on top of the article containing the contaminant-reagent to place the geotextile sheet or mats 115 and the copolymer contained separately in the geotextile material, between the lower flexible sheet material 136 between the geotextile sheet or mat 115 and the upper flexible water-impermeable base barrier layer 150. The adhesive reservoir 161 preferably applies an adhesive to the surface of the sheet material 150 to glue the sheet material 150 to the upper surface of the copolymer containing the geotextile sheet or mat 115.

[0045] The copolymer works in that it absorbs salt water with high conductivity, containing polyvalent ions, regardless of its particle size. The powdered or granular copolymer preferably consists of particles having a size in the range of about 10 pm to about 500 pm, preferably about 50 pm to about 1,000 pm, more preferably about 50 pm to about 800 pm, and most preferably the particle size distribution is about 50 pm to about 800 pm, with up to 100% of the particles in the range 50 pm to 200 pm, preferably about 10 wt. up to about 50 wt. in the range of 50 pm to 200 pm, from 50 to 90 wt. particles in the size range 200 pm to 800 pm.

[0046] As shown in FIG. 5, geocomposite products 10 described herein containing partially crosslinked acrylamide / acrylate / acrylic acid copolymers are particularly effective when placed vertically adjacent to the sea / soil 200 interface to protect the soil interface between penetration of saltwater 202 that could otherwise penetrate the sea / soil interface 200 to soil 204.

[0047] The geotextile sheet or mat 15 or 115 may be of a woven or nonwoven material, preferably a nonwoven. Suitable fibers for making the geotextile mat 15 or 115 include fibers made of rayon, polypropylene, polyesters, nylon, acrylic polymers and copolymers, ceramic fiber, glass fiber, propylene-ethylene copolymers, polypropylene-polyamide copolymers, monofilaments, polyethylene, polyurethane , cotton, jute and any other non-biodegradable or very slowly biodegradable fiber, preferably showing both bacteriological, hydrolytic and chemical resistance. In some installations, the thickness of the article is not important and such articles of any required thickness can be produced, e.g., 3 millimeters to about 4 inches, containing about 0.1 ounces to about 30 pounds per square foot of pollutant / reagent material.

[0048] The products described above can be modified in various ways to suit different tasks, and this ability to match products is one of the basic advantages compared to prior art water barriers. For example, the geocomposite products described herein can be loaded with a heavy material, such as metal mesh or a heavy mineral, such as barite, iron oxide or similar material, relatively evenly, together with a powdered or granular copolymer, such that the weight

The specificity of the entire product is greater than 1.0, which allows the material to be easily immersed in water. Therefore, the product can be applied to the soil surface at the bottom of a filled sludge pond, waste collection area and the like, without first draining the pond or waste storage area. A product containing heavy mineral can be developed at the upper level of an area for collecting water or waste and allow it to sink to cover the soil surface under the bottom under water or liquid waste material, thus saving time, effort and costs associated with sealing an existing sludge pond, area for collecting waste and the like, without first draining the pond or waste collection area.

[0049] In another embodiment, the products described herein may include a very light material incorporated therein, such as expanded vermiculite or expanded perlite, such that the product has significant buoyancy in water, in liquid waste materials and the like to form a covering in the area collecting liquid waste, such as a sludge pond for toxic wastewater, to prevent external compounds, dust and dirt from entering the waste collection area. One part of such cover material may be adapted to be removed or rolled up, so that additional toxic waste and similar substances can be added to the covered collection area while maintaining the water impermeable cover to prevent the waste collection area from being filled with rainwater.

[0050] The product described herein may be a non-woven material comprising essentially one copolymer, adhered to a water-impermeable cover layer, e.g., a sheet of polyvinyl chloride (PVC) as the primary barrier. Preferably, the geocomposite article comprises an upper barrier layer, such as a polyvinyl chloride (PVC) sheet material, glued to the woven or nonwoven sheet material containing a partially crosslinked acrylamide / acrylate / acrylic acid copolymer. In addition, drainage structures and other products used in the field of drainage can practically be introduced into this product during its manufacture, e.g. under the upper cover sheet. Herbicides, bactericidal materials, marker chemicals, various coloring agents that indicate contact with a particular chemical or class of chemicals, and the like can also be incorporated into the articles described herein.

[0051] The product is particularly effective in coastal wall conditions for protecting sheet steel sheet piles; vertical reinforcing elements and lagging; vertical reinforcing elements and earth installations; concrete caisson; ground stabilized wall structures and diaphragm wall structures.

[0052] The uses of the products described here filled or partially filled with powdered or granular material are virtually limitless, since the product can be made completely flexible, relatively rigid or stiff and can be applied to surfaces of various shape and slope, rough or smooth, as well as to vertical surfaces, such as foundation walls, dams, along the edges and at the bottom of channels, as in areas, on which large reservoirs are located, as well as in irrigation techniques and water resources management.

[0053] In order to demonstrate the ability of the partially crosslinked acrylamide / acrylate / acrylic acid copolymers to "self-heal" ("cure"), geocomposite test articles were prepared with geomembrane made of 0.045 inch adhesive PVC sheet material (using 2 , 30 grams of Bostik Supertak Aerosol Adhesive) for the material

EP2 217 439 B1 non-woven polyethylene terephthalate (PET) containing 2.96 grams STOCKOSORB S (partially crosslinked acrylamide / acrylate / acrylic acid copolymer) between the layers of geomembrane and nonwoven. PVC and PET sheet materials were round sheets, each 10 cm in diameter, 78.54 cm in area. In geocomposite test articles, a 1-inch incision was made through all layers, as shown in FIG. 5.

Test procedure: self-sealing efficiency [0054] 10 cm diameter circles were cut from the geocomposite test articles. In the test specimens, a 1-inch incision was then made through all layers, as shown in Figure 5, simulating geomembrane damage. The incised samples were then placed in a round measuring cell, sealed at the edges, at the bottom of a water tower exerting a pressure of 4 meters of salt water (4.5% sea salt; specific conductivity 53.2 mS / cm). A porous stone was placed on top of the incision ₂ weight simulating 20 lb / ft pressure exerted on the sample² without restricting the access of the sea salt solution to the gap. The measuring cell is then filled with the test solution exposing the sample to salt water under certain conditions. The amount of salt water that flows through the gap in the sample is collected and measured at specific intervals. The test is carried out as long as it is practiced for samples showing poor self-sealing and for at least 24 hours for samples showing good self-sealing. Typical test results are shown in FIG. 6. Data analysis [0055] The fluid flow versus time for the geocomposite sample for the study was plotted and the results were evaluated to determine the slope (flow rate in ml / min) after reaching the steady state by the fluid flow. The fluid flow for the geocomposite control sample was also measured. The geocomposite control sample consists of a water-impermeable membrane used in the test sample without an active self-sealing layer. The test apparatus was evaluated after the test to ensure that damage to the measuring cell did not affect the results.

[0056] The effectiveness of the test sample is given as the "self-sealing performance index" or "SPI", which is calculated using the following formula: SPI = S_T/ S_C, somewhere_T = fluid flow rate through the gap in the sample (ml / min) after reaching the steady state by the flow, and S_C = flow rate through the control sample (ml / min) after reaching a steady state flow.

[0057] To achieve the full benefits of the products and methods described herein, test articles as described above should have an SPI of less than 0.1, preferably less than 0.01, more preferably less than 0.015, even more preferably less than 0.005, and most preferably less than 0.001.

EP2 217 439 B1

<td>Test sample No.</td><td></td><td></td><td> 15</td><td> 16</td><td> 19</td><td> 20</td><td> 21</td><td> 25</td><td> 26</td><td> 28</td><td> 29</td><td> 30</td><td> 31</td><td> 32</td><td> 33</td>

<td>Core</td><td>control*</td><td>check 2 **</td><td>PVC</td><td>PVC</td><td>PVC</td><td>PVC</td><td>PVC</td><td>PVC</td><td>PVC</td><td>PVC</td><td>PVC</td><td>PVC</td><td>PVC</td><td>PVC</td><td>PVC</td>

<td>2 SAP for use in agriculture, g / foot</td><td> 0</td><td> 0</td><td> 35</td><td> 35</td><td> 35</td><td> 35</td><td> 35</td><td> 35</td><td> 35</td><td> 42</td><td> 42</td><td> 28</td><td> 28</td><td> 28</td><td> 35</td>

<td>SAP standard</td><td> 0</td><td> 35</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td>

<td>Sealing time (min)</td><td>ON</td><td>ON</td><td> 60</td><td> 330</td><td> 40</td><td> 14</td><td> 0</td><td> 355</td><td> 30</td><td> 2</td><td> 60</td><td> 70</td><td> 1</td><td> 16</td><td> 1</td>

<td>Sealing volume (ml)</td><td>ON</td><td>ON</td><td> 401</td><td> 206</td><td> 119</td><td> 198</td><td> 0</td><td> 372</td><td> 60</td><td> 4</td><td> 202</td><td> 241</td><td> 0</td><td> 164</td><td> 0.8</td>

<td>Water conductivity</td><td> 53,2</td><td> 53,2</td><td> 53,2</td><td> 53,2</td><td> 53,2</td><td> 53,2</td><td> 53,2</td><td> 53,2</td><td> 53,2</td><td> 53,2</td><td> 53,2</td><td> 53,2</td><td> 53,2</td><td> 53,2</td><td> 53,2</td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Salt solution flow rate ml / min</td><td> 139,4</td><td> 2,32</td><td> 0</td><td> 0,0577</td><td> 0</td><td> 0</td><td> 0</td><td> 0,00750</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0.011</td><td> 0</td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>SLEEPS</td><td>ON</td><td> 0,01665</td><td> 0</td><td>4,135 x 10^-4</td><td> 0</td><td> 0</td><td> 0</td><td>5,379 x 10^-5</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td>7,889 x 105</td><td> 0</td>

<td colspan="16">* Control: no partially crosslinked acrylamide / acrylate / acrylic acid copolymer (SAP grade for agricultural use) ** Control 2: Only partially cross-linked acrylate / acrylic acid copolymer (plain SAP)</td>

[0058] As shown in FIG. 6, a geocomposite control test product, containing a PVC layer adhered to a PET nonwoven layer, without a copolymer contained in the nonwoven, characterized by a rapid, linear leakage of salt water of about 139.4 ml / min. Geocomposite products made as described herein containing a partially crosslinked acrylamide / acrylate / acrylic acid copolymer (Test No. 1 for Test No. 7 - FIG. 6) showed leakage of salt water in the first 20-30 minutes until the copolymer was sufficiently swollen with salt water and the gap in the PVC was sealed. After about 30 minutes, there was little or no additional leakage of salt water through the crack in the geocomposite article.

[0059] In FIG. 7 shows the results for the control of FIG. 6 (PVC plus non-woven without a copolymer) and Test No. 1 for test No. 7 within 1440 minutes. Control samples showed a continuous leak, while in Samples 1-7 there was essentially no salt water leak after 20-30 minutes.