Moisture-impervious water-swellable clay-containing “water-stop” composition containing a water-penetrable coating
A waterproofing article in the form of rod-, or rope-shaped clay-containing compositions, and a method of waterproofing using the article, whereby a water-penetrable, degradable, or water-soluble film or coating forms an outer surface of the article for avoiding premature hydration of an underlying clay-containing composition. In the preferred embodiment, an inner core of a water-swellable clay-containing composition includes a coating of a water-removable or degradable material, completely encasing the major outer surfaces of the composition, having controlled, predetermined water-penetration; high pH degradability; or water-solubility so that the core of water-swellable clay-containing composition is quickly hydrated after water-penetration of the coating material, and to prevent clay hydration during installation, prior to water-penetration of the coating material.
1. A water barrier, in a shape of a rod or rope, having a length to width ratio of at least 10, adapted to be secured to an area of potential water flow comprising a flexible, water-impermeable, clay-containing composition core having a co-extruded coating layer of a water-penetrable material thereover, said coating layer having a predetermined water-penetration rate to allow for wetting of the coating layer during installation without hydrating the underlying clay.
2. The water barrier of claim 1 , wherein the coating is a water-soluble polymer coated continuously over the entire outer surface of the water-impermeable, clay-containing composition.
3. The water barrier of claim 2 , wherein the water-soluble polymer is selected from the group consisting of poly(acrylic acid), polyacrylate, poly(methacrylic acid), polymethacrylate, and mixtures thereof.
4. The water barrier of claim 2 , wherein the water-soluble polymer has a thickness in the range of about 0.1 mil to about 15 mils.
5. The water barrier of claim 4 , wherein the water-soluble polymer has a thickness in the range of about 1 to 3 mils.
6. The water barrier of claim 2 , wherein the water-soluble polymer is selected from the group consisting of: poly(vinyl alcohol); poly(vinyl acetate); copolymers of vinyl alcohol and vinyl acetate; polyvinylpyrrolidone; and combinations thereof.
7. The water barrier of claim 1 , wherein the coating layer of water-soluble material is co-extruded over the clay composition in an amount of about 1 to about 10 pounds of coating layer per 100 ft 2 of core surface area.
8. The water barrier of claim 1 , wherein the clay composition comprises about 10% to about 90% by weight clay and a material selected from the group consisting of polypropene, polybutene, and mixtures thereof in an amount of about 8% to about 65% by weight.
9. The water barrier of claim 8 , wherein the clay composition further includes an elastomer in an amount of about 1% to about 20% by weight.
10. The water barrier of claim 8 , wherein the clay is a smectite clay.
11. The water barrier of claim 10 , wherein the smectite clay is selected from the group consisting of sodium bentonite, sodium montmorillonite, calcium bentonite, calcium montmorillonite, magnesium bentonite, magnesium montmorillonite, iron bentonite, iron montmorillonite, beidellite, nontronite, hectorite, saponite, sepiolite, and combinations thereof.
12. The water barrier of claim 8 , wherein the coating layer is selected from the group consisting of guar, arabic, ghatti, tragacanth, agar, xanthan, karaya, locust bean, acacia, carrageenan, silicone gum, hydroxyethylcellulose, hydroxypropylcellulose, hydroxybutylcellulose, carboxymethylcellulose, sodium carboxymethylcellulose, gelatin, starch, modified starch, nonoxynol, oxtoxynol, ethoxylated fatty alcohol, propoxylated fatty alcohol, ethoxylated fatty acid, propoxylated fatty acid, ethoxylated fatty amine, propoxylated fatty amine, and mixtures thereof.
13. The water barrier of claim 8 , wherein the coating layer is a biodegradable polymer.
14. The coating layer of claim 8 , wherein the coating layer is a polymer that degrades at a pH above 9.
15. The water barrier of claim 1 , wherein the water-penetrable coating layer is poly(tetramethylene adipate-co-terephthalate).
16. A method of manufacturing a water barrier in a shape of a rod or rope, having a length to width ratio of at least 10, comprising extruding a core of a clay-containing composition and co-extruding an outer coating layer of a water-penetrable material thereover, said coating preventing water from contacting the core composition during installation and removable by water contact after installation.
17. The method of claim 16 , wherein the coating is a water-penetrable polymer coated continuously over the entire outer surface of the water-impermeable, water-swellable clay-containing composition.
18. The method of claim 17 , wherein the water-penetrable material is a water-soluble polymer.
19. The method of claim 18 , wherein the water-soluble polymer is selected from the group consisting of poly(acrylic acid), a metal salt of poly(acrylic acid), poly(methacrylic acid), a metal salt of poly(methacrylic acid), and mixtures there.
20. The method of claim 16 , wherein the water-penetrable material has a thickness in the range of about 0.1 mil to about 15 mils.
21. The method of claim 20 , wherein the water-penetrable material has a thickness in the range of about 1 mil to about 3 mils.
22. The method of claim 21 , wherein the coating layer is poly(tetramethylene adipate-co-terephthalate).
23. The method of claim 18 , wherein the water-soluble polymer is selected from the group consisting of poly(acrylic acid), polyacrylate, poly(methacrylic acid), polymethacrylate, and mixtures thereof.
24. The method of claim 16 , wherein the clay composition comprises about 35% to about 90% by weight of a smectite clay and a material selected from the group consisting of polypropene polybutene, and mixtures thereof in an amount of about 10% to about 65% by weight.
25. The method of claim 16 , further including the steps of cooling or drying the coating layer sufficiently to render the coating layer non-tacky, and coiling the dried water-barrier into a coil of water-barrier material.
26. The method of claim 25 , wherein the water barrier material is not in contact with a release sheet of material.
27. The method of claim 24 further including intercalating the polybutene or polypropene between adjacent clay platelets to exfoliate at least a portion of the clay into individual clay platelets.