# US 2008/0187756 A1 · Water-Absorbing Material Having a Coating of Elastic Film-Forming Polymers > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2008/0187756 A1 - Document ID: US20080187756A1 - Status: Published application - Kind: A1 - Application number: 11/815,267 - Filed: 2006-02-03 - Published: 2008-08-07 - Earliest claimed: 2005-02-04 - Assignees: BASF SE - Inventors: Ulrich Riegel; Thomas Daniel; Stefan Bruhns; Mark Elliot; Renae Dianna Fossum; Mattias Schmidt; Axel Meyer; James Scott Madsen - Web page: https://patentgrep.com/patent/US20080187756A1 ## CPC - A61L 15/60: Liquid-swellable gel-forming materials, e.g. super-absorbents - Y10T 428/2998: including synthetic resin or polymer - A61L: METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES (preservation of bodies or disinfecting characterised by the agents employed A01N; preserving, e.g. sterilising, food or foodstuffs A23; preparations for medical, dental or toiletry purposes A61K) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract The present invention relates to a water-absorbing material obtainable by a process comprising the steps of a) spray-coating water-absorbing polymeric particles with an elastic film-forming polymer in a fluidized bed reactor in the range from 00 C. to 500 C and b) heat-treating the coated particles at a temperature above 500 C. and also to a process for its production. ## Claims ### Claim at position 1 -39. (canceled) ### Claim 40 A water absorbing material obtainable by a process comprising a) spray-coating water-absorbing polymeric particles with an elastic film-forming polymer at temperatures in the range from 0° C. to 50° C. and b) heat-treating the coated particles at a temperature above 50° C. ### Claim 41 A water absorbing material obtainable by a process comprising a) spray-coating water-absorbing polymeric particles with an elastic film-forming polymer in a fluidized bed reactor in the range from 0° C. to 50° C. and b) heat-treating the coated particles at a temperature above 50° C. ### Claim 42 (depends on 40) The water-absorbing material according to claim 40, wherein the Core Shell Centrifuge Retention Capacity (CS-CRC) is not less than 20 g/g. ### Claim 43 (depends on 40) The water-absorbing material according to claim 40, wherein the CS-CRC and the CS-SFC (Core Shell Saline Flow Capacity) satisfies the following inequality; Log(CS-SFC′/150)>2.5−0.095×CS-CRC, where CS-SFC′=CS-SFC×107 and the dimension of 150 is [cm3s/g]. ### Claim 44 (depends on 40) The water-absorbing material according to claim 40, wherein the water-absorbing polymeric particles are post-crosslinked. ### Claim 45 (depends on 40) The water-absorbing material according to claim 40, wherein the elastic film-forming polymer is a polyurethane. ### Claim 46 (depends on 40) The water-absorbing material according to claim 40, wherein the elastic film-forming polymer is a polyetherpolyurethane. ### Claim 47 (depends on 46) The water-absorbing material according to claim 46, wherein the polyetherpolyurethane has a fraction of alkylene glycol units in the side chains which is from 10% to 90% by weight based on the total weight of the polyetherpolyurethane. ### Claim 48 (depends on 47) The water-absorbing material according to claim 47, wherein the fraction of ethylene oxide units in the side chains of the polyetherpolyurethane is not less than 12% by weight and the fraction of ethylene oxide units in the main chains of the polyetherpolyurethane is not more than 30% by weight based on the total weight of the polyetherpolyurethane. ### Claim 49 (depends on 46) The water-absorbing material according to claim 46, wherein the fraction of alkylene oxide units in the polyetherpolyurethane is not more than 90% by weight based on the total weight of the polyetherpolyurethane. ### Claim 50 (depends on 40) The water-absorbing material according to claim 40, wherein the material is obtained by applying the elastic film-forming polymer in an amount of 0.1-25 parts by weight (calculated as solids material) to 100 parts by weight of dry water-absorbing polymeric particles. ### Claim 51 (depends on 40) The water-absorbing material according to claim 40, wherein the material is obtained by applying the elastic film-forming polymer in an amount of <5 parts by weight (calculated as solids material) to 100 parts by weight of dry water-absorbing polymeric particles. ### Claim 52 (depends on 40) The water-absorbing material according to claim 40, wherein the material is obtained by spray-coating in a continuous process in a fluidized bed reactor. ### Claim 53 (depends on 40) A water-absorbing material according to claim 40, wherein the material is obtained by spray-coating water-absorbing polymeric particles with an elastic film-forming polymer at temperatures in the range from 0° C. to less than 45° C. ### Claim 54 (depends on 40) The water-absorbing material according to claim 40, wherein the material is obtained by coating the water-absorbing polymeric particles by spraying with an aqueous dispersion of the elastic film-forming polymer. ### Claim 55 (depends on 54) The water-absorbing material according to claim 54, wherein the viscosity of the aqueous polymeric dispersion is less than 500 mPas. ### Claim 56 (depends on 40) The water-absorbing material according to claim 40, wherein the coating is applied in a Wurster Coater or in a Glatt-Zeller coater or in a continuous fluidized bed reactor or in a continuous spouted bed reactor. ### Claim 57 (depends on 40) The water-absorbing material according to claim 40, wherein the gas stream in the Wurster Coater is selected such that the relative moisture at the point of exit of the gas stream is in the range from 10% to 90%. ### Claim 58 (depends on 40) The water-absorbing material according to claim 40, wherein the material is obtained by heat-treating in the fluidized bed. ### Claim 59 (depends on 40) The water-absorbing material according to claim 40, wherein a deagglomerating aid is added prior to the heat-treating. ### Claim 60 (depends on 40) The water-absorbing material according to claim 40, wherein the heat-treating is carried out at a temperature in the range from 100 to 200° C. ### Claim 61 (depends on 40) The water-absorbing material according to claim 40, wherein the heat-treating and optionally the coating are carried out under inert gas. ### Claim 62 (depends on 40) The water-absorbing material according to claim 40, obtained by a process comprising a) spray-coating water-absorbing polymeric particles with an elastic film-forming polymer in a fluidized bed reactor in the range from 0° C. to 50° C. and b) optionally coating the particles obtained according to a), with a deagglomerating aid and subsequently c) heat-treating the coated particles at a temperature above 50° C. and subsequently d) cooling the heat-treated particles to below 90° C. ### Claim 63 (depends on 40) The water-absorbing material according to claim 40 wherein the CS-CRC and the CS-SFC (Core Shell Saline Flow Capacity) satisfies the following inequality: Log(CS-SFC′/150)>3.36−0.133×CS-CRC, where CS-SFC′=CS-SFC×107 and the dimension of 150 is [cm3s/g]. ### Claim 64 (depends on 40) A process for producing a water-absorbing material according to claim 40 comprising a) spray-coating water-absorbing polymeric particles with an elastic film-forming polymer in a fluidized bed reactor in the range from 0° C. to 50° C. and b) heat-treating the coated particles at a temperature above 50° C. ### Claim 65 (depends on 64) The process according to claim 64, wherein the water-absorbing polymeric particles are spray-coated with an aqueous dispersion of the film-forming polymer. ### Claim 66 (depends on 65) The process according to claim 65, wherein the viscosity of the aqueous polymeric dispersion is less than 500 mPas. ### Claim 67 (depends on 64) Process according to claim 64, wherein the coating is applied in a Wurster Coater or in a Glatt-Zeller coater or in a continuous fluidized bed reactor or in a continuous spouted bed reactor. ### Claim 68 (depends on 67) Process according to claim 67, wherein the gas stream in the fluidized bed reactor is selected such that the relative moisture at the point of exit of the gas stream is in the range from 10% to 90%. ### Claim 69 (depends on 64) Process according to claim 64, wherein the heat-treating is carried out in a continuous fluidized bed. ### Claim 70 (depends on 64) Process according to claim 64, wherein a deagglomerating aid is added prior to the heat-treating. ### Claim 71 (depends on 64) Process according to claim 64, wherein the heat-treating is carried out at a temperature in the range from 100 to 200° C. ### Claim 72 (depends on 64) Process according to claims 64, wherein the heat-treating and optionally the coating are carried out under inert gas. ### Claim 73 A water-absorbing material comprising water-absorbing polymeric particles coated with an elastic film-forming polyurethane, wherein the polyurethane comprises not only side chains having polyethylene oxide units but also polyalkylene oxide units in the main chain. ### Claim 74 (depends on 73) The water-absorbing material according to claim 73, wherein the Core Shell Centrifuge Retention Capacity (CS-CRC) of the water-absorbing polymeric particles is not less than 20 g/g. ### Claim 75 (depends on 73) The water-absorbing material according to claim 73, wherein the CS-CRC and the CS-SFC satisfies the following inequality: Log(CS-SFC′/150)>2.5−0.095×CS-CRC, where CS-SFC′=CS-SFC×107 and the dimension of 150 is [cm3s/g]. ### Claim 76 (depends on 73) The water-absorbing material according to claim 73, wherein the water-absorbing polymeric particles are postcrosslinked. ### Claim 77 A water absorbing material obtained by a process comprising a) spray-coating water-absorbing polymeric particles with an elastic film-forming polymer in a fluidized bed reactor in a continuous process and b) heat-treating the coated particles at a temperature above 50° C. ### Claim 78 (depends on 77) The process for producing a water-absorbing material according to claim 77, comprising a) spray-coating water-absorbing polymeric particles with an elastic film-forming polymer in a fluidized bed reactor in a continuous process and b) heat-treating the coated particles at a temperature above 50° C.