Flexible polyurea foams having controlled load bearing qualities

A flexible, water-blown polyurea foam formed from reaction of a reaction mixture containing at least one polyisocyanate component;

• 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 aromtic, secondary aliphatic, Lewis acid-blocked primary or secondary aliphatic or aromatic amine groups or mixtures of such groups:
• and an amount of at least one alkali metal halide salt effective to increase load bearing strength of the foam over that of a foam having the same components but without the alkali metal halide salt.

A flexible, water-blown polyurea foam formed from 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, said foam having multiple areas of differing load bearing strength corresponding to areas having differing relative proportions of at least one alkali metal halide salt.

A method 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, said foam having areas of differing load bearing strength, by incorporating therein differing concentrations of at least one alkali metal halide salt in each of the areas.

An active hydrogen composition comprising (a) at least one active hydrogen compound wherein active hydrogen compounds of relatively high equivalent weight have an average of from about 1.5 to about 4 active hydrogen-containing groups per molecule, of which active hydrogen-containing groups:

• an average of (1) from about 5 to about 60 percent are primary aliphatic amine groups or (2) 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;
• (b) from about 2 to about 12 parts by weight of water per 100 parts by weight component (a);
• and (c) an alkali metal halide salt in an amount sufficient to increase the load bearing strength of a foam made by reacting the active hydrogen composition with a polyisocyanate over the load bearing strength of a foam having the same components but without the alkali metal halide salt.