# US 8,784,681 B2 · Self-situating stimuli-responsive polymer compositions in soil additives and methods for use > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,784,681 B2 - Document ID: US8784681B2 - Status: Granted - Kind: B2 - Application number: 12/384,067 - Filed: 2009-03-31 - Published: 2009-10-01 - Granted: 2014-07-22 - Earliest claimed: 2008-03-31 - Assignees: Rhodia Operations - Applicants: Zhiyun Chen; Jean-Christophe Castaing; Marie-Pierre Labeau; Gilda Lizarraga - Inventors: Zhiyun Chen; Jean-Christophe Castaing; Marie-Pierre Labeau; Gilda Lizarraga - Web page: https://patentgrep.com/patent/US8784681B2 ## CPC - C05G 3/80: Soil conditioners - C05D 9/02: containing trace elements - C05G 5/40: Fertilisers incorporated into a matrix - C09K 17/22: Polyacrylates; Polymethacrylates - C09K 17/32: of natural origin, e.g. cellulosic materials - C09K 17/40: containing mixtures of inorganic and organic compounds - C09K 17/48: Organic compounds mixed with inorganic active ingredients, e.g. polymerisation catalysts - C09K 17/50: the organic compound being of natural origin, e.g. cellulose derivatives - C05G: MIXTURES OF FERTILISERS COVERED INDIVIDUALLY BY DIFFERENT SUBCLASSES OF CLASS C05; MIXTURES OF ONE OR MORE FERTILISERS WITH MATERIALS NOT HAVING A SPECIFIC FERTILISING ACTIVITY, e.g. PESTICIDES, SOIL-CONDITIONERS, WETTING AGENTS (organic fertilisers containing added bacterial cultures, mycelia, or the like C05F11/08; organic fertilisers containing plant vitamins or hormones C05F11/10); FERTILISERS CHARACTERISED BY THEIR FORM - C05D: INORGANIC FERTILISERS NOT COVERED BY SUBCLASSES C05B, C05C; FERTILISERS PRODUCING CARBON DIOXIDE - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE ## Abstract Disclosed are soil additives comprised of self-situating, stimuli-responsive polymer compositions and methods of their use. In one embodiment, the polymer composition or polymer network comprises permanent cross-links and non-permanent cross-links, wherein the non-permanent cross-links are capable of being removed upon application or exposure to a stimulus, typically located within the soil. In another embodiment, the method of increasing water retention in soils includes applying a soil additive, comprising polymer networks of the present invention admixed with an aqueous solution to form a colloidal dispersion solution or suspension, to a soil surface. The suspension or colloidal dispersion solution facilitates penetration of the polymer composition through the soil surface and into the soil, migrating typically to lower water potential areas and, more typically, along drainage channels located within the soil. After penetration of the soil surface, the polymer network is then exposed to a stimulus, typically present in the soil, whereby the non-permanent cross-links are removed and the polymer composition undergoes a volumetric change. This results in the prevention, arrest or decelerated loss of water from the targeted area, for example the plant root zone, which allows for improved water usage efficiency by plants, grasses, vegetation, etc. ## Claims ### Claim 1 A soil additive comprising particles having a first polymer structure having a mean particle diameter (D50) of from about 0.1 micrometers to about 200 micrometers, the first structure comprising permanent cross-links and non-permanent ionic cross-links, the particles having a property such that only upon contact with a monovalent stimulus selected from the group consisting of sodium ions, potassium ion, ammonium ions and any combination thereof present in soil, the non-permanent ionic cross-links become at least partially removed from the first structure via ion exchange with the monovalent stimulus, resulting in a second structure having a D50 of from about 1 micrometer to about 5000 micrometers and a volume greater than the first structure, the ratio of volume of the first structure to the second structure being from about 1:3 to 1:500, wherein the ionic cross-links are derived from a cation selected from the group consisting of calcium, magnesium, zinc, copper, ferrous, barium, and any combination thereof. ### Claim 2 (depends on 1) The soil additive of claim 1 wherein the first structure has a substantially crystalline form and the second structure has a substantially non-crystalline form. ### Claim 3 (depends on 1) The soil additive of claim 1 wherein the polymer composition comprises a random, block, star-shape, grafted copolymer or any combination thereof. ### Claim 4 (depends on 1) The soil additive of claim 1 wherein the polymer composition is selected from the group consisting of polyacrylamide, poly(methacrylic acid), poly(acrylic acid), polyacrylate, poly(ethylene glycol), poly(vinyl alcohol), polyglycerol, polytetrahydrofuran, polyamide, a derivative of any of the foregoing and a copolymer of any of the foregoing. ### Claim 5 (depends on 1) The soil additive of claim 1 wherein the polymer composition comprises one or more carboxylic groups selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, sorbic acid, maleic acid, itaconic acid, cinnamic acid, a salt of any of the foregoing, an anhydride of any of the foregoing and a combination of any of the foregoing. ### Claim 6 (depends on 1) The soil additive of claim 1 wherein the polymer composition is formed from at least one monomer comprising acrylate, methacrylate, acrylamide, methacrylamide, vinyl alcohols, allyl alcohols, vinyl acetates, betaine-containing monomers, ethylenically unsaturated monomers, derivatives thereof or copolymers of any of the foregoing. ### Claim 7 (depends on 1) The soil additive of claim 1 wherein the polymer composition is selected from the group consisting of guar gum, hydroxypropyl guar gum, carboxymethyl guar gum, carboxymethylhydroxypropyl guar gum, starch, corn, wheat, rice, potato, tapioca, waxy maize, sorghum, waxy sarghum, sago and modified starches such as dextrinated, hydrolysed, oxidized, crosslinked, alkylated, hydroxyalkylated, acetylated, fractionated and physically modified starches, dextrin, chitin, chitosan, alginate compositions, xanthan gum, carageenan gum, gum karaya, gum Arabic, pectin and glass-like polysaccharides, cellulose, hydroxycellulose, hydroxyalkyl cellulose, hydroxyethyl cellulose, carboxymethylhydroxyethyl cellulose, hydroxypropyl cellulose and derivates of any of the foregoing. ### Claim 8 (depends on 1) The soil additive of claim 1 further comprising an inorganic material. ### Claim 9 (depends on 8) The soil additive of claim 8 wherein the inorganic material is selected from the group consisting of clay, diatom, silicate, silica, sand, calcium carbonate and any combination of the foregoing. ### Claim 10 (depends on 1) The soil additive of claim 1 wherein the polymer composition comprises a colloidal dispersion or aqueous suspension solution. ### Claim 11 A method of increasing water retention in soil comprising applying a soil additive to soil, the soil additive comprising particles having a first polymer structure having a mean particle diameter (D50) of from about 0.1 micrometers to about 200 micrometers, the first structure comprising permanent cross-links and non-permanent ionic cross-links, the particles having a property such that only upon contact with a monovalent stimulus selected from the group consisting of sodium ions, potassium ions, ammonium ions, and any combination thereof present in soil, the non-permanent ionic cross-links become at least partially removed from the first structure via ion exchange with the monovalent stimulus, resulting in a second structure having a D50 of from about 1 micrometer to about 5000 micrometers and a volume greater than the first structure, the ratio of the volume of the first structure to the second structure being from about 1:3 to 1:500, wherein the ionic cross-links are derived from a cation selected from the group consisting of calcium, magnesium, zinc, copper, ferrous, barium, and any combination thereof. ### Claim 12 (depends on 11) The method of claim 11 wherein the polymer composition is selected from polyacrylamide, poly(methacrylic acid), poly(acrylic acid), polyacrylate, poly(ethylene glycol), poly(vinyl alcohol), polyglycerol, polytetrahydrofuran, polyamide, guar gum, hydroxypropyl guar gum, carboxymethyl guar gum, carboxymethylhydroxypropyl guar gum, starch, corn, wheat, rice, potato, tapioca, waxy maize, sorghum, waxy sarghum, sago and modified starches such as dextrinated, hydrolysed, oxidized, crosslinked, alkylated, hydroxyalkylated, acetylated, fractionated and physically modified starches, dextrin, chitin, chitosan, alginate compositions, xanthan gum, carageenan gum, gum karaya, gum Arabic, pectin and glass-like polysaccharides, cellulose, hydroxycellulose, hydroxyalkyl cellulose, hydroxyethyl cellulose, carboxymethylhydroxyethyl cellulose, hydroxypropyl cellulose, derivates of any of the foregoing or copolymers of any of the foregoing. ### Claim 13 (depends on 11) The method of claim 11 wherein the polymer composition comprises a colloidal dispersion or aqueous suspension solution that is capable of flowing into one or more water drainage channels present in the soil. ### Claim 14 (depends on 11) The method of claim 11 wherein the polymer composition comprises a colloidal dispersion or aqueous suspension solution that is capable of flowing from an area of high water potential to an area of relatively low water potential in the soil. ### Claim 15 (depends on 13) The method of claim 13 wherein the second structure is capable of effectuating a greater distribution of water in the soil relative to distribution of water in the soil prior to application of the soil additive. ### Claim 16 (depends on 15) The method of claim 15 wherein the second structure impedes or arrests the flow of water through the water drainage channels. ### Claim 17 (depends on 11) The method of claim 11 wherein the polymer composition in the second structure is maintained at a depth below the soil surface less than or equal to about 20 feet for a predetermined amount of clogging time. ### Claim 18 (depends on 11) The method according to claim 11 further comprising applying the soil additive to a target area of soil, whereby the soil additive is capable of forming a stable colloidal dispersion or suspension with water and penetrating the surface of the target area. ### Claim 19 (depends on 18) The method of claim 18 wherein the cross-linked polymer composition is selected from the group consisting of polyacrylamide, poly(methacrylic acid), poly(acrylic acid), polyacrylate, poly(ethylene glycol), poly(vinyl alcohol), polyglycerol, polytetrahydrofuran, polyamide, guar gum, hydroxypropyl guar gum, carboxymethyl guar gum, carboxymethylhydroxypropyl guar gum, starch, corn, wheat, rice, potato, tapioca, waxy maize, sorghum, waxy sarghum, sago and modified starches such as dextrinated, hydrolysed, oxidized, crosslinked, alkylated, hydroxyalkylated, acetylated, fractionated and physically modified starches, dextrin, chitin, chitosan, alginate compositions, xanthan gum, carageenan gum, gum karaya, gum Arabic, pectin and glass-like polysaccharides, cellulose, hydroxycellulose, hydroxyalkyl cellulose, hydroxyethyl cellulose, carboxymethylhydroxyethyl cellulose, hydroxypropyl cellulose, derivates of any of the foregoing or copolymers of any of the foregoing. ### Claim 20 (depends on 18) The method of claim 18 wherein the polymer composition comprises a colloidal dispersion or aqueous suspension solution that is capable of flowing from an area of high water potential to an area of relatively low water potential in the target area. ### Claim 21 (depends on 18) The method of claim 18 wherein the polymer composition comprises a colloidal dispersion or aqueous suspension solution that is capable of flowing into one or more water drainage channels present in soil in the target area. ### Claim 22 (depends on 21) The method of claim 21 wherein the second structure is capable of effectuating a greater distribution of water in the soil relative to distribution of water in the soil prior to application of the soil additive. ### Claim 23 (depends on 21) The method of claim 21 wherein the second structure impedes or arrests the flow of water through the water drainage channels. ### Claim 24 (depends on 18) The method of claim 18 wherein the polymer composition in the second structure is maintained at a depth below the target area surface less than or equal to about 20 feet for a predetermined amount of time. ### Claim 25 (depends on 18) The method of claim 18 wherein the polymer composition under the surface of the target area forms a substantially continuous distribution layer having a height of from about 0.1 to about 20 centimeters. ### Claim 26 (depends on 18) The method of claim 18 wherein the polymer composition under the surface of the target area forms a substantially continuous distribution layer having a height of from about 0.1 to about 3 centimeters. ### Claim 27 (depends on 18) The method of claim 18 wherein the polymer composition under the surface of the target area forms a substantially continuous layer having a height of less than about 0.5 centimeters. ### Claim 28 (depends on 18) The soil additive of claim 18 further comprising the step of optimizing the polymer composition to correspond to the mean pore size of soil in the target area.