A breathable
polyurethane having an upright
moisture vapor
transmission rate (MVTR) of more than about 500 gms / m2 / 24 hr comprises:(a) poly(alkylene
oxide) side-chain units in an amount comprising about 12 wt. % to about 80 wt. % of said
polyurethane, wherein (i) alkylene
oxide groups in said poly(alkylene
oxide) side-chain units have from 2 to 10 carbon atoms and are unsubstituted, substituted, or both unsubstituted and substituted, (ii) at least about 50 wt. % of said alkylene oxide groups are
ethylene oxide, and (iii) said amount of said side-chain units is (i) at least about 30 wt. % when the molecular weight of said side-chain units is less than about 600 grams / mole, (ii) at least about 15 wt. % when the molecular weight of said side-chain units is from about 600 to about 1,000 grams / mole, and at least about 12 wt. % when the molecular weight of said side-chain units is more than about 1,000 grams / mole, and(b) poly(
ethylene oxide) main-chain units in an amount comprising less than about 25 wt. % of said
polyurethane.Coatings and films for textiles and other articles and applications using such polyurethanes have excellent breathability, i.e., high
moisture vapor transmission rates (MVTR).