Polymers with engineered segment molecular weight
Polymer compositions and processes for extended glycols and under-capping glycols for production of polymer compositions with engineered hard and soft segment molecular weights are provided. Also provided are fibers and articles of manufacture such as fabrics and garments produced from these polymer compositions and processes.
1 . A process for producing an isocyanate-terminated prepolymer by glycol extension for use in forming a segmented polyurethane or polyurethaneurea polymer with engineered soft segment and hard segment molecular weights with an HSWT % of from 3.62% to 7.79% and a segment molecular weight ratio (SSMW/HSMW) larger than 12.0, said method comprising: (a) reacting an excess amount of a lower molecular weight glycol with a diisocyanate to form an extended glycol derived from a glycol having a molecular weight of 1400 to 2500; and (b) reacting the formed extended glycol with an excess amount of a diisocyanate to produce an isocyanate-terminated prepolymer or capped glycol,
wherein the isocyanate-terminated prepolymer or capped glycol exhibits a SET % of from 1.8% to 18%.
2 . The process of claim 1 wherein the diisocyanate used in step (a) to make the extended glycol can be same or different from the diisocyanate used in step (b) to make the capped glycol prepolymer.
3 . The process of claim 1 further comprising dissolving the capped glycol prepolymer in a solvent and chain extending with a diol or diamine to form a segmented polyurethane or polyurethaneurea polymer with engineered soft segment and hard segment molecular weights.
4 . A process for under-capping glycols for production of a polymer with engineered hard and soft segment molecular weights, said method comprising:
(a) adding a diisocyanate to a glycol at a low capping ratio to produce an under-capped capped glycol, wherein the glycol has a molecular weight of 1400 to 2500;
(b) adding additional diisocyanate to the capped glycol; and
(c) adding a chain extender to produce the polymer with engineered hard and soft segment molecular weights,
wherein the polymer has an HSWT % of from 3.62% to 7.79%, and
wherein the polymer exhibits a SET % of from 10.8% to 18%.
5 . The process of claim 4 wherein molecular weight of the soft segment is increased without reducing molecular weight of the hard segment.
6 . The process of claim 4 wherein the glycols are selected from 3-methyl THF copolyether glycol or PTMEG.
7 . The process of claim 4 wherein the diisocyanate used in step (a) is methylene diphenyl diisocyanate.
8 . The process of claim 4 wherein the chain extender is ethylene diamine.
9 . The process of claim 1 where steps (a) and (b) are performed with heat.
10 . A polymer with engineered hard and soft segment molecular weights produced in accordance with the process of claim 1 .
11 . A fiber made from the polymer in claim 10 .
12 . An article of manufacture at least a portion of which comprises the fiber of claim 11 .