Spandex with high uniformity
View Patent ↗Disclosed herein are a highly uniform spandex and process for making such spandex. More particularly, the polyurethaneurea of which such spandex is prepared has both dialkylurea and cycloalkylurea ends, wherein a chain terminator composition includes a dialkylamine such as diethylamine and a cylcoalkylamine such as cyclohexylamine.
1. An article comprising at least one spandex fiber comprising a polyurethaneurea which is the reaction product of:
(a) a NCO-terminated prepolymer comprising the reaction product of
(i) a polyolmeric glycol selected from the group consisting of a polyether glyol, a polyester polyol, a polycarbonate glycol, and combinations thereof; and
(ii) a diisocyanate;
(b) a chain extender comprising at least a first diamine and a second diamine; and
(c) a chain terminator composition including cyclohexylamine and diethylamine;
wherein said polyurethaneurea comprises a mole ratio of said first diamine to said second diamine of about 75:25 to about 85:15; and diethylurea ends of about 10 meq/Kg to about 60 meq/Kg.
2. The article of claim 1 , wherein said polyurethaneurea comprises diethylurea ends of about 12 meq/Kg to about 24 meq/Kg.
3. The article of claim 1 , wherein said polyurethaneurea comprises a viscosity stabilizer.
4. The article of claim 3 , wherein said viscosity stabilizer is present in an amount of about 50 ppm to about 250 ppm.
5. The article of claim 1 , wherein first diamine comprises ethylenediamine and said second diamine comprises 2-methyl-1,5-pentamethylenediamine (MPMD).
6. The article of claim 1 , wherein said polymeric glycol has a number average molecular weight of 1600 to about 2200.
7. The article of claim 1 , wherein said NCO-terminated prepolymer has %NCO from about 2.3 to about 3.0.
8. The article of claim 1 , wherein said NCO-terminated prepolymer has %NCO from about 2.5 to about 2.7.
9. The article of claim 1 , wherein said polymeric glycol comprises polytetramethyleneether glycol.
10. The article of claim 1 , wherein said diisocyanate comprises a diphenylmethane diisocyanate (MDI).
11. The article of claim 1 , wherein said article is a knit.
12. The article of claim 11 , wherein said knit is selected from warp knit and circular knit.
13. a process for making spandex including of:
(a) providing a polymeric glycol selected from the group consisting of a polyether glycol, a polyester glycol, a polycarbonate glycol, and combinations thereof;
(b) providing a diisocyanate;
(c) contacting the polymeric glycol and diisocyanate to form a NCO-terminated prepolymer;
(d) providing a chain extender comprising at least a first diamine and a second diamine;
(e) providing a chain terminator composition including cyclohexylamine and diethylamine;
(f) contacting the NCO-terminated prepolymer glycol, the chain extender and the chain terminatorcomposition in a solvent to form a polyurethaneurea in solution; and
(g) spinning the polyurethaneurea in solution to form the spandex,
wherein said polyurethaneurea comprises a mole ratio of said first diamine to said second diamine of about 75:25 to about 85:15; and diethylurea ends of about 10 meq/Kg to about 60 meq/Kg.