Polyurethane composition and method of preparation

A metal storage container suitable for storing 25 percent sulfuric acid having a protective innerliner of a thickness of from about 3 to about 100 mils of a polyurethane composition prepared by reacting 2,2.sup.1 -diaminodiphenyldisulfide with a prepolymer having a free isocyanate content of about 2 to about 8 percent, said prepolymer having been prepared by reacting in the presence of from about 1 to about 5 parts by weight of a 2,6 dialkylated para cresol having the formula:

• ##SPC2##
• where R is an alkyl radical having from 4 to 12 carbon atoms;
• (1) 100 parts by weight of an hydroxyl containing polymeric polyol having a molecular weight of from about 1000 to about 5000, a corresponding hydroxyl number of of from 110 to about 20 and an hydroxyl functionality of of from about 2 to about 3 and where the polymeric polyol comprises from about 70 to about 100 percent units derived from conjugated dienes selected from the group consisting of 1-3 butadiene and isoprene and up to about 30 percent units derived from styrene;
• and (2) a diphenyl methane diisocyanate, where the ratio of primary amino groups of of said diaminodisulfide to free isocyanate groups of said prepolymer is in the range of 0.5/1 to about 1/1.