Prepolymer, polyol composition and process for making a flexible foam

The invention relates to having 5% to 30% of NCO of isocyanate terminated pre-polymer, which is excess diphenylmethane diisocyanate and polyoxyethylene - parts of propylene glycol and polyalcohol reaction product; Wherein the diphenylmethane diisocyanate is at least 80% wt% 4,4 ' - diphenyl methane diisocyanate, wherein the polyoxyethylene parts of propylene polyol having 2000 to 10000 average molecular weight, 2 to 6 average nominal hydroxyl functionalities, 21% to 45% by weight of the ethylene content, Had-po-po/eo-eo structure; the PO block PO occupied 60% to 90%, wherein the end EO∶ the non-specifications EO ratio of 3∶1 to 1∶3; The relates to a method for soft the foamed body, the method to make the pre-polymer a mould according to the pre-polymer component with the following components and index is 70 to 120: b1) one of polyoxyethylene parts of propylene polyol, the average nominal hydroxyl functionality of 2 to 6, an ethylene content is greater than 50% wt%; A, optionallyb2) one of polyoxyethylene parts of propylene polyol, the average nominal hydroxyl functionality of 2 to 6, EO content is 20% to 50% by weight; the content of hydroxyl is at least 50%, wherein the total weight of the methyl and Tert-butyl group; A c), waterA and d) from known additive and agent.