Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From reactant having at least one -n=c=x group as well as...
Reexamination Certificate
2001-11-14
2003-01-07
Gorr, Rachel (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From reactant having at least one -n=c=x group as well as...
C528S061000, C528S906000
Reexamination Certificate
active
06503996
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a highly uniform spandex and to a process for making such spandex using specific ingredients. More particularly, the polyurethaneurea of which such spandex is comprised has both alkylurethane and monoalkylurea ends, and such ingredients include selected aliphatic primary monoalcohols and aliphatic primary monoamines.
2. Description of Background Art
A variety of polyurethaneurea compositions useful for making spandex are disclosed in U.S. Pat. Nos. 3,994,881; 5,948,875; 5,981,686; 4,871,818; 4,973,647; 5,000,899 and Japanese Published Patent Application JP08-020625. U.S. Pat. No. 5,589,563 discloses the use of surface modifying endgroups, particularly for biomedical polymers. Monofunctional chain terminators are disclosed in U.S. Pat. Nos. 3,384,623; 3,184,426; 5,032,664; British Patent GB 1102819; Japanese Published Patent Applications JP7-278246; JP2000-103831; and JP02-51518 and International Application WO99/62979. British Patents GB1153739; GB118737; and GB1118735 disclose the use of acid and acid-generating compounds in the manufacture of elastic polyurethane filaments.
However, none of the prior art disclosures make possible sufficiently uniform spandex or adequate spandex spinning continuity, and improvements in spandex uniformity and in processes to make spandex are still needed.
SUMMARY OF THE INVENTION
The invention provides a spandex comprising a polyurethaneurea which is the reaction product of:
a) a capped glycol comprising the reaction product of:
i) a polymeric glycol selected from the group consisting of polyether glycols, polyester glycols, and polycarbonate glycols;
ii) a diisocyanate; and
iii) an aliphatic primary monoalcohol comprising 1-10 carbons;
b) an aliphatic diamine chain extender comprising 2-12 carbons; and
c) a primary aliphatic monoamine chain terminator comprising 5-12 carbons;
wherein:
the polyurethaneurea has:
monoalkylurea ends and alkylurethane ends;
a ratio of monoalkylurea ends to alkylurethane ends of at least about 0.5:1; and
a ratio of monoalkylurea ends to alkyurethane ends of at most about 10: 1; and wherein the spandex has a coefficient of denier variation which is lower by at least about 15% than that of spandex comprising an otherwise identical polyurethaneurea having dialkylurea and amine ends.
The invention also provides a process for making spandex comprising the steps of:
a) providing a polymeric glycol selected from the group consisting of polyether glycols, polyester glycols, and polycarbonate glycols;
b) providing a diisocyanate;
c) providing an aliphatic primary monoalcohol comprising 1-10 carbons;
d) contacting the glycol, diisocyanate, and monoalcohol to form a capped glycol;
e) providing an aliphatic diamine chain extender comprising 2-12 carbons;
f) providing primary aliphatic monoamine chain terminator comprising 5-12 carbons;
g) contacting the capped glycol, the diamine, and the monoamine in a solvent to form a polyurethaneurea solution; and
h) spinning the polyurethaneurea solution to form the spandex,
wherein:
a mole ratio of monoamine to monoalcohol is at least about 0.5:1; and
a mole ratio of monoamine to monoalcohol is at most about 10:1.
DETAILED DESCRIPTION OF THE INVENTION
It has now been found that spandex comprising a polyurethaneurea having alkylurethane and monoalkylurea chain ends at certain ratios has unexpectedly high uniformity. It has also been found that certain combinations of selected aliphatic monoalcohols and aliphatic monoamines, when used in making a polyurethaneurea to be spun into spandex, provide unexpected process advantages.
As used herein, ‘spandex’ means a manufactured fiber in which the fiber-forming substance is a long chain synthetic polymer comprised of at least 85% by weight of a segmented polyurethane. Polyurethaneureas constitute a subgroup of polyurethanes. “Primary” amine or alcohol means that the amino or hydroxyl group is covalently bonded to a carbon which is in turn covalently bonded to at most one other carbon.
Polyurethaneureas which have been chain-terminated with an aliphatic monoalcohol have alkylurethane ends, and those that have been chain-terminated with an aliphatic primary amine have monoalkylurea ends. Chain termination with (secondary) dialkylamines gives dialkyl urea ends. Amine ends in the polyurethaneurea are derived from incompletely reacted diamine chain extender.
The spandex of the invention comprises a polyurethaneurea having a ratio of monoalkylurea ends to alkylurethane ends of at least about 0.5:1 and at most about 10:1. When the ratio is outside the indicated range, the spandex has low denier (decitex) uniformity. The polyurethaneurea can have at least about 5 meq/kg and at most about 30 meq/kg alkylurethane ends. The polyurethaneurea can have at least about 2 meq/kg monoalkylurea ends and at most about 55 meq/kg monoalkylurea ends, based on polyurethaneurea weight. The polyurethaneurea can have up to about 50 meq/kg amine ends, based on polyurethaneurea weight. The values herein for the various types of polyurethaneurea chain ends include consideration of unreactive ends in the polymeric glycol, which generally amount to less than about 10 meq/kg, based on total ingredients weight or polyurethaneurea weight, as circumstances dictate.
Further, the spandex has a coefficient of denier variation which is lower, by at least about 15% and preferably at least about 25%, than that of spandex comprising an otherwise identical polyurethaneurea having dialkylurea and amine ends. Such a reduction in coefficient of denier variation is significant. Preferably, the spandex has a coefficient of denier variation of at most about 15.
The polyurethaneurea constituent of the spandex of the invention is the reaction product of a) a capped glycol made from a polymeric glycol selected from the group consisting of polyether glycols, polyester glycols, and polycarbonate glycols, a diisocyanate, and an aliphatic primary monoalcohol comprising 1-10 carbons; b) an aliphatic diamine chain extender comprising 2-12 carbons; and c) a primary aliphatic monoamine chain terminator comprising 5-12 carbons.
The process of the present invention comprises contacting a polymeric glycol, an aliphatic primary monoalcohol, and a diisocyanate to form a capped glycol, contacting the capped glycol with an aliphatic diamine chain extender and an aliphatic primary monoamine chain terminator in a solvent, and wet- or dry-spinning the resulting solution of polyurethaneurea to form the spandex. The mole ratio of monoamine to monoalcohol is at least about 0.5:1 and at most about 10:1. When the ratio is too high, the monoalcohol has little effect, and when it is too low, the polyurethaneurea can become insufficiently soluble in the spinning solvent.
Polymeric glycols suitable for use in making the polyurethaneurea of which the spandex of the invention is comprised and in the process of the invention can have number average molecular weights of approximately 1500-4000 daltons and include polyether glycols (for example poly(tetramethyleneether) glycol which can have a molecular weight of 1500-2500 daltons and poly(tetramethyleneether-co-2-methyltetramethyleneether) glycol which can have a weight of 2000-4000 daltons), polycarbonate glycols (for example poly(pentane-1,5-carbonate) glycol and poly(hexane-1,6-carbonate) glycol), and polyester glycols (for example poly(2,2-dimethyl-1,3-propane dodecanedioate) glycol, poly(ethylene-co-1,2-propylene adipate) glycol, poly(hexamethylene-co-2,2-dimethyltrimethylene adipate) glycol, and poly(ethylene-co-butylene adipate) glycol). If desired, poly(2,2-dimethyl-1,3-propane dodecanedioate) glycol can be short-path distilled in one or more steps at reduced pressures and elevated temperatures before being capped with diisocyanate. When poly(tetramethyleneether-co-2-methyltetramethyleneether) glycol is used, the 2-methyltetramethyleneether moiety can be present in a range of approximately 4-20 mol %, based on the total ether moieties in the glycol. Such a copolyether can be prepared
Bretches Donald D.
Lodoen Gary A.
DuPont Dow Elastomers L.L.C.
Gorr Rachel
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