| abstract |
A method for the preparation of flexible polyurethane foams by reacting a prepolymer having an NCO value of 5-10 % by weight which is the reaction product obtained by reacting an excessive amount of a polyisocyanate containing at least 85 % by weight of 4,4'-diphenylmethane diisocyanate or a variant thereof with a polyol having an average nominal hydroxyl functionality of from 2.5 to 3.5, an average hydroxyl equivalent weight of from 1000 to 3000, and an oxyethylene content of from 50 to 85 % by weight with water, the amount of water being at least 20 parts by weight per 100 parts by weight of prepolymer. |