# US 10,307,732 B2 · Particulate superabsorbent polymer composition having improved stability and fast absorption > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,307,732 B2 - Document ID: US10307732B2 - Status: Granted - Kind: B2 - Application number: 14/781,630 - Filed: 2014-04-07 - Published: 2016-03-03 - Granted: 2019-06-04 - Earliest claimed: 2013-04-10 - Assignees: Evonik Corporation - Applicants: Evonik Corporation - Inventors: Gonglu Tian; Matthew Thomas Ondisco; David L. Bergman; Bernfried Messner; Scott J. Smith; Michael M. Azad; Mark Joy - Web page: https://patentgrep.com/patent/US10307732B2 ## CPC - B01J 20/3234: {Inorganic material layers} - A61L 15/18: containing inorganic materials - A61L 15/60: Liquid-swellable gel-forming materials, e.g. super-absorbents - B01J 20/265: {modified or post-treated polymers (polymer carriers or substrates subjected to further impregnating or coating B01J20/3208)} - B01J 20/3208: {Polymeric carriers, supports or substrates} - B01J 20/3236: {containing metal, other than zeolites, e.g. oxides, hydroxides, sulphides or salts} - B01J 20/3282: {Crosslinked polymers} - C08F 220/06: Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof - C08J 3/12: Powdering or granulating - C08J 3/126: {Polymer particles coated by polymer, e.g. core shell structures} - C08J 3/24: Crosslinking, e.g. vulcanising, of macromolecules (mechanical aspects B29C35/00; crosslinking agents C08K) - C08J 9/224: Surface treatment - B01J 2220/68: Superabsorbents - C08J 2343/04: Homopolymers or copolymers of monomers containing silicon - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS - 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) - C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS - C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29) ## Abstract The present invention relates to a fast particulate superabsorbent polymer composition comprising a polymer comprising a neutralized aluminum salt solution applied to the surface of a particulate superabsorbent polymer; wherein an aqueous solution of the neutralized aluminum salt has a pH value from about 5.5 to about 8; and subsequent to subjecting the particulate superabsorbent polymer composition to the Processing Test, the particulate superabsorbent polymer composition has a permeability stability index of from about 0.60 to about 0.99, and a compressibility from 1.30 mm2/N to about 4 mm2/N as measured by the Compression Test, and wherein the particulate superabsorbent polymer composition may have a Vortex time of from 25 to 60 seconds and absorbency under load at 0.9 psi of from 15 to 21 g/g. ## Claims ### Claim 1 A particulate superabsorbent polymer composition comprising a particulate superabsorbent polymer comprising from about 0.05 to about 2.0 wt. % based on the total amount of the polymerizable unsaturated acid group containing monomer solution of a foaming agent, and from about 0.001 to about 1.0 wt. % based on the total amount of the polymerizable unsaturated acid group containing monomer solution of a mixture of a lipophile nonionic surfactant polyethoxylated hydrophilic nonionic surfactant, and from 0.01 wt % to about 5 wt % based on the particulate superabsorbent polymer composition weight of a neutralized aluminum salt applied to the surface of the particulate superabsorbent polymer, in the form of an aqueous neutralized aluminum salt solution having a pH value from about 5.5 to about 8; wherein the particulate superabsorbent polymer composition has a Centrifuge Retention Capacity (CRC) of from about 25 grams to about 40 grams of 0.9 weight percent sodium chloride aqueous per gram of the particulate superabsorbent polymer composition, wherein the CRC is measured either before or after subjecting the superabsorbent polymer composition to a Processing Test, and an absorbency under load at 0.9 psi prior to subjecting the particulate superabsorbent polymer composition to the Processing Test of from 15 g/g to 21 g/g; and a Free Swell Gel Bed Permeability (FSGBP) of from about 30×10−8 cm2 to about 200×10−8 cm2 prior to subjecting the particulate superabsorbent polymer composition to the Processing Test; wherein the particulate superabsorbent polymer composition has a Vortex time of from 25 to 60 seconds as measured by the Vortex Test, and has a permeability stability index of from 0.60 to 0.99 when subjecting the particulate superabsorbent polymer composition to a Processing Test and a compressibility of from 1.30 mm2/N to about 4 mm2/N as measured by the Compression Test. ### Claim 2 (depends on 1) The particulate superabsorbent polymer composition of claim 1 wherein the lipophile nonionic surfactant has a HLB of from 4 to 9 and the polyethoxylated hydrophilic nonionic surfactant has a HLB of from 12 to 18. ### Claim 3 (depends on 1) The particulate superabsorbent polymer composition of claim 1 wherein the mixture of a lipophile nonionic surfactant and a polyethoxylated hydrophilic nonionic surfactant has a HLB of from 8 to 14. ### Claim 4 (depends on 3) The particulate superabsorbent polymer of claim 3 wherein the lipophile nonionic surfactant is a sorbitan ester and the polyethoxylated hydrophilic nonionic surfactant is a polyethoxylated sorbitan ester. ### Claim 5 (depends on 1) The particulate superabsorbent polymer composition of claim 1 comprising an internal crosslinker agent comprising a silane compound comprising at least one vinyl group or allyl group and at least one Si—O bond wherein the vinyl group or allyl group is directly attached to a silicon atom, wherein the particulate superabsorbent polymer composition has a Centrifuge Retention Capacity (CRC) Increase of at least 2 g/g based on CRC Increase=CRC(bt,5 hr)−CRC(rt,0.5 hr) wherein CRC Increase measures the increase in the CRC that occurs and is calculated as the difference between the second CRC Test and first CRC Test, and bt refers to body temperature and rt refers to room temperature. ### Claim 6 (depends on 5) The particulate superabsorbent polymer composition of claim 5 wherein said silane compound is selected from one of the following wherein R1 represents C2 to C3 alkenyl, R2 represents H, C1 to C4 alkyl, C2 to C5 alkenyl, C6 to C8 aryl, C2 to C5 carbonyl, R3 represents H, C1 to C4 alkyl, C6 to C8 aryl, R4 and R5 independently represent H, C1 to C4 alkyl, C6 to C8 aryl, m represents an integer of from 1 to 2, n represents an integer of from 2 to 3, l represents an integer of from 0 to 1, m+n+1=4, x represents an integer larger than 1, and y represents an integer of 0 or larger than 0. ### Claim 7 (depends on 6) The particulate superabsorbent polymer composition of claim 6 wherein said silane compound is selected from vinyltriisopropenoxy silane, vinyltriacetoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, diethoxymethylvinyl silane, and polysiloxane comprising at least two vinyl groups. ### Claim 8 A particulate superabsorbent polymer composition comprising a particulate superabsorbent polymer comprising an internal crosslinker agent comprising a silane compound comprising at least one vinyl group or allyl group and at least one Si—O bond wherein the vinyl group or allyl group is directly attached to a silicon atom, and from 0.01 wt % to about 5 wt % based on the particulate superabsorbent polymer composition weight of a neutralized aluminum salt applied to the surface of the particulate superabsorbent polymer, in the form of an aqueous neutralized aluminum salt solution having a pH value from about 5.5 to about 8; wherein the particulate superabsorbent polymer composition has a Centrifuge Retention Capacity (CRC) of from about 25 grams to about 40 grams of 0.9 weight percent sodium chloride aqueous per gram of the particulate superabsorbent polymer composition, wherein the CRC is measured either before or after subjecting the superabsorbent polymer composition to a Processing Test, and an absorbency under load at 0.9 psi prior to subjecting the particulate superabsorbent polymer composition to the Processing Test of from 15 g/g to 21 g/g; and an original Free Swell Gel Bed Permeability (FSGBP) of from about 30×10−8 cm2 to about 200×10−8 cm2 prior to subjecting the particulate superabsorbent polymer composition to the Processing Test; and a permeability stability index of about 0.60 to 0.99 when subjecting the particulate superabsorbent polymer composition to a Processing Test, and a compressibility of from 1.30 mm2/N to about 4 mm2/N as measured by the Compression Test, and a Centrifuge Retention Capacity (CRC) Increase of at least 2 g/g or more based on CRC Increase=CRC(bt,5 hr)-CRC(rt,0.5 hr) wherein CRC Increase measures the increase in the CRC that occurs and is calculated as the difference between the second CRC Test and first CRC Test, and bt refers to body temperature and rt refers to room temperature. ### Claim 9 (depends on 8) The particulate superabsorbent polymer composition of claim 8 wherein said silane compound is selected from one of the following wherein R1 represents C2 to C3 alkenyl, R2 represents H, C1 to C4 alkyl, C2 to C5 alkenyl, C6 to C8 aryl, C2 to C5 carbonyl, R3 represents H, C1 to C4 alkyl, C6 to C8 aryl, R4 and R5 independently represent H, C1 to C4 alkyl, C6 to C8 aryl, m represents an integer of from 1 to 2, n represents an integer of from 2 to 3, l represents an integer of from 0 to 1, m+n+1=4, x represents an integer larger than 1, and y represents an integer of 0 or larger than 0. ### Claim 10 (depends on 9) The particulate superabsorbent polymer composition of claim 9 wherein said silane compound is selected from vinyltriisopropenoxy silane, vinyltriacetoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, diethoxymethylvinyl silane, and polysiloxane comprising at least two vinyl groups. ### Claim 11 A process for the production of a particulate superabsorbent polymer composition comprising the following steps: a) preparing an aqueous monomer solution of a mixture of a polymerizable unsaturated acid group containing monomer and an internal crosslinking agent monomer wherein the aqueous monomer solution comprises dissolved oxygen; b) sparging the aqueous monomer solution of step a) including adding an inert gas to the aqueous monomer solution of step a) to replace the dissolved oxygen of the aqueous monomer solution; c) polymerizing the aqueous monomer solution of step b) including the steps of c1) adding to the aqueous monomer solution of step a): i) an aqueous solution comprising from about 0.05 to about 2.0 wt. % based on the total amount of the polymerizable unsaturated acid group containing monomer solution of a foaming agent; and ii) an aqueous solution comprising from about 0.001 to about 1.0 wt. % based on the total amount of the polymerizable unsaturated acid group containing monomer solution of a mixture of a lipophile surfactant and a polyethoxylated hydrophilic surfactant; c2) treating the monomer solution of step c1) to high speed shear mixing to form a treated monomer solution, wherein the components i) an aqueous solution comprising from about 0.1 to about 1.0 wt. % of a foaming agent; and ii) an aqueous solution comprising from about 0.001 to about 1.0 wt. % of a mixture of a lipophile surfactant and a polyethoxylated hydrophilic surfactant are added to the aqueous monomer solution after step b) of sparging the aqueous monomer solution and before step c2) of high speed shear mixing of the aqueous monomer solution; c3) forming a hydrogel by adding a polymerization initiator to the treated monomer solution of step c2) wherein the initiator is added to the treated monomer solution after the foaming agent and the mixture of surfactants, wherein the polymer is formed to include bubbles of the foaming agent into the polymer structure; and d) drying and grinding the hydrogel of step c) to form particulate superabsorbent polymer; and e) surface crosslinking the particulate superabsorbent polymer of step d) with a surface crosslinking agent; b) preparing a neutralized aluminum salt in the form of an aqueous solution having a pH value from about 5.5 to about 8; and; c) applying the aqueous neutralized aluminum salt solution on the surface of the particulate superabsorbent polymer composition; and wherein the particulate superabsorbent polymer composition has a degree of neutralization of from about 50% mol to about 80 mol %; and the particulate superabsorbent polymer composition has a Centrifuge Retention Capacity of from about 25 grams to about 40 grams of 0.9 weight percent sodium chloride aqueous per gram of the particulate superabsorbent polymer composition, wherein the CRC is measured either before or after subjecting the particulate superabsorbent polymer composition to a Processing Test, and an absorbency under load at 0.9 psi prior to subjecting the particulate superabsorbent polymer composition to the Processing Test of from 15 g/g to 21 g/g; and a Free Swell Gel Bed Permeability (FSGBP) of about 30×10−8 cm2 to about 200×10−8 cm2 prior to subjecting the treated particulate superabsorbent polymer composition to the Processing Test; and wherein the particulate superabsorbent polymer composition has a permeability stability index of from 0.60 to 0.99 when subjecting the particulate superabsorbent polymer composition to a Processing Test, and a compressibility from 0.30 mm2/N to about 4 mm2/N as measured by the Compression Test, and wherein the particulate superabsorbent polymer composition has a vortex time of from about 25 sec to about 60 sec as measured by the Vortex Test. ### Claim 12 (depends on 11) The process for making the particulate superabsorbent polymer composition according to claim 11 wherein said aqueous aluminum salt solution has a pH value from about 6 to 7. ### Claim 13 (depends on 11) The process for making the particulate superabsorbent polymer composition according to claim 11 wherein particles have a particle diameters of smaller than 600 μm and not smaller than 150 μm in an amount of not less than about 90 wt % of the particulate superabsorbent polymer composition. ### Claim 14 (depends on 11) The process for making the particulate superabsorbent polymer composition according to claim 11 wherein said neutralized aluminum salt is selected from: a) the reaction product of sodium hydroxide with aluminum sulfate or aluminum sulfate hydrate; b) the reaction product of an organic acid with sodium aluminate; c) the reaction product of sodium aluminate with aluminum sulfate or aluminum sulfate hydrate; or d) the reaction product of an organic acid or its salt with sodium aluminate and aluminum sulfate or aluminum sulfate hydrate. ### Claim 15 (depends on 11) The process for making the particulate superabsorbent polymer composition of claim 11 wherein the lipophile surfactant is nonionic and has a HLB of from 4 to 9 and the polyethoxylated hydrophilic surfactant is nonionic and has a HLB of from 12 to 18. ### Claim 16 (depends on 11) The process for making the particulate superabsorbent polymer composition of claim 11 wherein the mixture of a lipophile surfactant and a polyethoxylated hydrophilic surfactant has a HLB of from 8 to 14. ### Claim 17 (depends on 11) The process for making the particulate superabsorbent polymer composition of claim 11 wherein the lipophile surfactant is a sorbitan ester and the polyethoxylated hydrophilic surfactant is a polyethoxylated sorbitan ester. ### Claim 18 (depends on 11) The process for making the particulate superabsorbent polymer composition of claim 11 wherein the foaming agent is selected from sodium carbonate or sodium bicarbonate. ### Claim 19 (depends on 11) The process for making the particulate superabsorbent polymer composition of claim 11 comprising from about 0.05 to about 1.0 wt. % based on the total amount of the polymerizable unsaturated acid group containing monomer solution of the polymerization initiator. ### Claim 20 (depends on 11) The process for making the particulate superabsorbent polymer composition of claim 11 wherein the lipophile surfactant is nonionic and the polyethoxylated hydrophilic surfactant is nonionic. ### Claim 21 (depends on 11) The process for making the particulate superabsorbent polymer of claim 11 wherein the internal crosslinker agent comprises a silane compound comprising at least one vinyl group or allyl group and at least one Si—O bond wherein the vinyl group or allyl group is directly attached to a silicon atom, wherein the particulate superabsorbent polymer has a Centrifuge Retention Capacity (CRC) Increase of 2 g/g or more based on CRC Increase=CRC(bt,5 hr)−CRC(rt,0.5 hr) wherein CRC Increase measures the increase in the CRC that occurs and is calculated as the difference between the second CRC Test and first CRC Test, and bt refers to body temperature and rt refers to room temperature. ### Claim 22 (depends on 21) The process for making the particulate superabsorbent polymer composition of claim 21 wherein said silane compound is selected from one of the following wherein R1 represents C2 to C3 alkenyl, R2 represents H, C1 to C4 alkyl, C2 to C5 alkenyl, C6 to C8 aryl, C2 to C5 carbonyl, R3 represents H, C1 to C4 alkyl, C6 to C8 aryl, R4 and R5 independently represent H, C1 to C4 alkyl, C6 to C8 aryl, m represents an integer of from 1 to 2, n represents an integer of from 2 to 3, l represents an integer of from 0 to 1, m+n+1=4, x represents an integer larger than 1, and y represents an integer of 0 or larger than 0. ### Claim 23 (depends on 22) The process for making the particulate superabsorbent polymer of claim 22 wherein said silane compound is selected from vinyltriisopropenoxy silane, vinyltriacetoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, diethoxymethylvinyl silane, and polysiloxane comprising at least two vinyl groups.