US 11,891,471 B2
Flexible polyurethane foams with high water absorption capacity
Markus Schuette, Lemfoerde (DE); Heinz-Dieter Lutter, Lemfoerde (DE); and Anne Schubert, Lemfoerde (DE)
Assigned to BASF SE, Ludwigshafen am Rhein (DE)
Appl. No. 17/427,769
Filed by BASF SE, Ludwigshafen am Rhein (DE)
PCT Filed Jan. 31, 2020, PCT No. PCT/EP2020/052407
§ 371(c)(1), (2) Date Aug. 2, 2021,
PCT Pub. No. WO2020/161010, PCT Pub. Date Aug. 13, 2020.
Claims priority of application No. 19155983 (EP), filed on Feb. 7, 2019.
Prior Publication US 2022/0106433 A1, Apr. 7, 2022
Int. Cl. A61F 13/00 (2006.01); A61L 26/00 (2006.01); C08G 18/10 (2006.01); C08G 18/30 (2006.01); C08G 18/48 (2006.01); C08G 18/76 (2006.01); C08J 9/02 (2006.01)
CPC C08G 18/485 (2013.01) [A61L 26/0019 (2013.01); A61L 26/0085 (2013.01); C08G 18/10 (2013.01); C08G 18/7671 (2013.01); C08J 9/02 (2013.01); C08G 2110/0008 (2021.01); C08G 2110/0058 (2021.01); C08G 2110/0066 (2021.01); C08G 2110/0083 (2021.01); C08J 2205/06 (2013.01); C08J 2207/10 (2013.01); C08J 2375/08 (2013.01)] 14 Claims
 
1. A process for producing a hydrophilic flexible polyurethane foam, comprising mixing
(a) at least one polyurethane prepolymer (a) having an isocyanate content of 5 to 10% by weight, based on the weight of the at least one polyurethane prepolymer (a), and
(b) at least one aqueous component (b)
in a ratio by weight of the at least one polyurethane prepolymer (a) to the at least one aqueous component (b) from 3:1 to 1:1.2 and allowing the mixture to react to form the flexible polyurethane foam,
wherein the at least one polyurethane prepolymer (a) is obtained by mixing and reacting at least one isocyanate (a1) with at least one polyetherol (a2),
wherein:
the at least one isocyanate (a1) comprises methylenediphenylene diisocyanate,
the at least one polyetherol (a2) has a hydroxyl number of 30 to 60 mg KOH/g and an ethylene oxide content of at least 60% by weight, based on the total weight of ethylene oxide and propylene oxide used to prepare the at least one polyetherol (a2), the at least one difunctional and/or trifunctional starter molecule in a first step up to a hydroxyl number of 400 to 1200 mg KOH/g, followed by an alkoxylation of the propoxylated starter molecule with a mixture of ethylene oxide and propylene oxide and finally an ethoxylation of the alkoxylation product thus obtained with 2 to 10% by weight ethylene oxide, based on the alkylene oxide used for producing the at least one polyetherol (a2), and
the at least one aqueous component (b) comprises at least 90% by weight water (b1) and up to 10% by weight non-silicone-containing surface-active substances (b2), based in each case on the total weight of the at least one aqueous component (b).