Patent ID: 6586486
Filing Date: 2003-07-01
Classification: C08G

Abstract:
A process for the preparation of low-density hydrophilic flexible polyurethane foams comprising reacting organic and/or modified organic polyisocyanates (a) with a polyetherol mixture (b) and, optionally, further compounds (c) having hydrogen atoms reactive toward isocyanates, in the presence of water and/or other blowing agents (d), catalysts (e) and, optionally further assistants and additives (f), wherein the polyetherol mixture (b) comprisesb1) at least one difunctional or polyfunctional polyetherol based on propylene oxide and/or butylene oxide and ethylene oxide, having an ethylene oxide content of more than 60% by weight, based on the total amount of alkylene oxide used, an OH number of from 20 to 120 mg KOH/g and a content of primary OH groups of more than 20% and b2) at least one difunctional to polyfunctional polyetherol free of ethylene oxide and based on propylene oxide and/or butylene oxide and having an OH number of more than 25 mg KOH/g, water is used in amounts of up to 15% by weight, based on the total weight of the components (b) to (f), and the catalysts comprise a mixture of gel catalysts and blowing catalysts, and foaming is effected in an index range of from 20 to 120 wherein the amount by weight of (b1) is greater than that of (b2) such that the weight ratio of (b1) to (b2) is from 2:1 to 40:1.