Melt spun thermoplastic polyurethanes useful as textile fibers

10) A process of preparing a polyurethane polymer fiber precursor, the process comprising the steps of:

• a) obtaining a polyol prepolymer which is a member selected from the group consisting of hydroxyl terminated polyester glycols, hydroxyl terminated polyether/polyester glycols, and mixtures thereof;
• b) adding a first organic diisocyanate to the polyol prepolymer wherein the mole ratio of diisocyanate to prepolymer is about 1.2 to 1:1.1 to obtain a first mixture;
• c) reacting the first mixture of first organic diisocyanate and polyol prepolymer at a temperature of about 60° C. to about 100° C. and at atmospheric pressure for a time of about 20 minutes to about 100 minutes to obtain a first “soft” polymer having a viscosity of about 50-800 poises;
• d) obtaining a low molecular weight glycol having terminal hydroxyl groups;
• e) adding a second organic diisocyanate to the glycol wherein the mole ratio of isocyanate to hydroxyl is about 1.2 to about 1:1.2 to obtain a second mixture;
• f) reacting the second mixture of second organic diisocyanate and low molecular weight glycol at a temperature of about 50° C. to about 70° C. and at atmospheric pressure for a time of about 2 minutes to about 10 minutes to obtain a second “hard” polymer;
• g) combining the first “soft” polymer from (c) with the second “hard” polymer from (f) in an extruder to obtain a combination of polymers wherein the mole ratio of isocyanate functionality to hydroxyl functionality in the combination is about 0.98:1 to about 1.2:1;
• h) reacting the combination of polymers in the extruder under polymerization and high mixing conditions and at a temperature of about 125° C. to about 260° C. for a time of about 2 minutes to about 8 minutes and at atmospheric pressure to obtain a final polyurethane polymer;
• and
• j) extruding the final polyurethane polymer to obtain a solid product of polyurethane polymer fiber precursor.

20) A process for preparing a polyurethane polymer fiber precursor, the process comprising the steps of:

• (a) obtaining a polyol prepolymer which is a member selected from the group consisting of hydroxyl terminated polyester glycols, hydroxyl terminated polyether/polyester glycols, and mixtures thereof;
• (b) adding an organic diisocyanate to the polyol prepolymer wherein the mole ratio of isocyanate to hydroxyl is about 1:2 to about 1:1.1 to obtain a first mixture;
• (c) reacting a first mixture of organic diisocyanate and polyol prepolymer at a temperature of about 60° C. to about 100° C. and at atmospheric pressure for a time of about 20 minutes to about 100 minutes to obtain a first “soft” polymer and unreacted diisocyanate;
• (d) obtaining a low molecular weight glycol having terminal hydroxyl groups;
• (e) adding the first polymer and the unreacted diisocyanate from step (c) to the low molecular weight glycol in a reaction extruder to obtain a second mixture wherein the mole ratio of isocyanate group to hydroxyl group approaches 1.000;
• (f) reacting the second mixture of first “soft” polymer, unreacted diisocyanate and low molecular weight glycol in a reaction extruder under polymerization and high mixing conditions and at a temperature of about 125° C. to about 260° C. for a time of about 2 minutes to about 8 minutes and at atmospheric pressure to obtain a final polyurethane polymer;
• and
• (g) extruding the final polyurethane polymer to obtain a solid product of polyurethane polymer fiber precursor.