Flexible polyurea foams having controlled load bearing qualities

摘要

The invention includes a process for preparing a flexible, water-blown polyurea foam by reacting a reaction mixture containing at least one polyisocyanate component and an active hydrogen component, wherein active hydrogen compounds of relatively high equivalent weight have an average of about 1.5 to about 4 active hydrogen-containing groups per molecule, of which active hydrogen-containing groups: an average of (a) from about 5 to about 60 percent are primary aliphatic amine groups or (b) at least about 25 percent are primary aromatic, secondary aliphatic, Lewis acid-blocked primary or secondary aliphatic or aromatic amine groups or mixtures of such groups. An amount of at least one alkali metal halide salt effective to increase load bearing strength of the foam is incorporated into the reaction mixture. Differing amounts of alkali metal halide salts are suitably incorporated into different areas of the foam to produce areas having differing load bearing strengths. The invention includes the foams formed by the processes of the invention as well as active hydrogen compositions containing the alkali metal halide salts and useful in the processes.