Method for making over-indexed thermoplastic polyurethane elastomer precursor and thermoplastic polyurethane elastomer made from the precursor

A method for making over-indexed thermoplastic polyurethane elastomer, said method comprising:

• making an over-indexed thermoplastic polyurethane elastomer precursor having unreacted isocyanate moieties by combining reactants and reacting them to form an over-indexed thermoplastic polyurethane elastomer precursor,
• cooling the over-indexed thermoplastic polyurethane elastomer precursor in water to form cooled precursor,
• pelletizing the cooled precursor to form cooled precursor pellets,
• drying the cooled precursor pellets to a moisture concentration less than about 800 ppm to form dried over-indexed thermoplastic polyurethane elastomer precursor,
• packaging the dried over-indexed thermoplastic polyurethane elastomer precursor in moisture-resistant packaging under conditions that essentially maintain the moisture content of the dried over-indexed thermoplastic polyurethane elastomer precursor at or below about 800 ppm;
• and
• removing the dried over-indexed thermoplastic polyurethane elastomer precursor from the package and curing the dried over-indexed thermoplastic polyurethane elastomer precursor by contact with water.

A method for making an article comprising over-indexed thermoplastic polyurethane elastomer, said method comprising:

• making an over-indexed thermoplastic polyurethane elastomer precursor having unreacted isocyanate moieties by combining reactants and reacting them to form an over-indexed thermoplastic polyurethane elastomer precursor,
• cooling precursor in water and pelletizing cooled precursor to form precursor pellets,
• drying the precursor pellets to a moisture concentration less than about 800 ppm to form dried precursor pellets,
• processing the dried precursor pellets to form an article precursor, and curing the article precursor by contact with water to form the article.