PROCEDURE FOR PREPARING RIGID FOAMS OF POLYURETHANE.

摘要

Continuous process for the preparation of rigid compressed and cold deformable open cell polyurethane foams according to the double conveyor belt process in which I) component A) and component B) are mixed in a mixing unit at temperatures of 20 at 35 ° C in a ratio such that the NCO index amounts to 95 to 125, II) the mixture of I) is introduced between the two protective layers of a double conveyor belt equipment at temperatures of 40 to 100 ° C, III) after passing the tape and after cooling if one or both protective layers are removed and finally the cooled product is cut if necessary, characterized in that as component A) a) an organic polyisocyanate component of a1) 70 to 90% is used by weight of monomeric diphenylmethanediisocyanate with a proportion of 18 to 32% by weight, based on the organic polyisocyanate component, 2,4 '' - diphenylmethanediisocyanate and a2) 10 to 30% by weight of polyf enylpolimethylene polyisocyanate and because as component B) b) polyhydroxy compounds of b1) 20 to 35% by weight, based on component B), of polyoloxyalkylenes having a functionality of 2 to 3 and with a hydroxyl number of 25 to 40, b2 are used ) 20 to 30% by weight, based on component B), of polyoloxyalkylenes with a functionality of 3 to 4 and with a hydroxyl number of 400 to 650, b3) 5 to 15% by weight, based on component B), of polyoloxyalkylenes with a functionality of 2 and with a hydroxyl number of 150 to 550, b4) 15 to 30% by weight, based on component B), of polyesters with a functionality of 2 and with a hydroxyl number of 200 to 350, b5) 4 to 7% by weight, based on component B), of glycerin c) 3.5 to 5.5% by weight, based on component B), of water as an expanding agent, d) 0.5 to 4 % by weight, referred to component B), of catalysts, e) 0.5 to 2% by weight, referred to component B), of foam stabilizers, f) 1 to 3.5% by weight, referred to to component B), of cell openers, g) 0 to 7% by weight, based on component B), of adjuvants and / or additives.