Verfahren zur Herstellung von Polyurethanprepolymeren

摘要

Polyurethane prepolymers which may be cured to form polyurethanes are prepared by reacting one mole of a polyglycol of M.W. 500-5000 with at least 1.5 moles of a diisocyanate to form an isocyanate-terminated prepolymer having more than 0.5% of unreacted diisocyanate and distilling the crude prepolymer thus formed under reduced pressure at a temperature below 225 DEG C. to obtain a prepolymer containing no more than 0.5% of unreacted diisocyanate. The polyglycols may be polyethers or polyesters, especially poly(ethylene adipate) glycol. Conventional diisocyanates are used and the prepolymer may be cured with glycols or diamines.