Process for making clear polyurethane/urea elastomers

摘要

A process for making clear elastomers is disclosed. First, a polyol having a narrow molecular weight distribution (Mw/Mn<1.5) reacts an aromatic diisocyanate at an NCO/OH ratio from about 1.3 to about 3.0 to give a non-viscous isocyanate-terminated prepolymer. A mixture that contains this prepolymer and an aliphatic diisocyanate is then reacted with an aromatic diamine to give a clear elastomer. The elastomers have excellent overall physical and mechanical properties, including resilience greater than 55%. The elastomers are valuable for in-line skates and other applications for which clarity is important.