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
2002-11-01
2004-04-13
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...
C528S906000
Reexamination Certificate
active
06720403
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to polyurethaneureas which are soluble in amide solvents and which are prepared from a polymeric glycol, at least one alkyl substituted 1,1′-methylenebis(4-isocyanatobenzene), and at least one doubly-hindered diamine. The present invention also relates to segmented polyurethaneurea fibers, dry-spun or wet-spun, comprising such polyurethaneureas and having superior whiteness retention, heat-set efficiency, and low percent set.
BACKGROUND
For the sake of convenience, and not of limitation, the present invention herein is discussed in terms of spandex, but should be construed to include all embodiments described in the following disclosure and equivalents.
Spandex has found widespread use in the apparel industry, such as in hosiery, foundation garments and sportswear where an elastic polymer imparts beneficial properties. Spandex is susceptible to discoloration under certain environmental conditions, for example in the presence of elevated temperatures and atmospheric gases such as nitrogen dioxide. The thermal stability of spandex is of particular interest because spandex-containing fabrics and garments are typically heat-set to provide dimensional stability and to shape the finished garment. In the manufacture of tricot knits and women's hosiery, for example, spandex is often knit into the fabric with nylon. After knitting, the fabric is frequently heat-set to remove wrinkles and stabilize the dimensions of the fabric. Typical heat-setting temperatures used in commercial operations are 195° C. for fabrics containing spandex and 6,6-nylon, 190° C. when the fabric contains 6-nylon, and 180° C. when the fabric contains cotton. It is also desirable to heat-set fabrics containing cotton and spandex, but if the spandex has adequate heat-set efficiency only at temperatures used for nylon- containing fabrics, the spandex cannot be properly heat-set in cotton-containing fabrics, which will be damaged by exposure to the required high temperatures. Improved heat-setting efficiency is desirable to save energy and improve productivity, and reduced discoloration by heat is desirable to provide an improved appearance. It is desirable, therefore, to prepare a spandex having a combination of good environmental resistance (“whiteness retention”) and high heat-set efficiency thus saving energy and improving productivity, especially if the mechanical properties of the spandex are not adversely affected.
DESCRIPTION OF THE ART
A variety of methods have been used to improve the heat-set efficiency of spandex and thereby lower the temperature at which the spandex can be heat-set. For example, the use of 15-32 mole percent of 2-methyl-1,5-pentanediamine as a coextender in making spandex is disclosed in U.S. Pat. No. 4,973,647,but such low levels do not provide spandex with sufficiently high heat-set efficiency at the moderate temperatures permitted for fabrics containing cotton. U.S. Pat. Nos. 5,000,899, 5,948,875 and 5,981,686 disclose the use of high proportions of 2-methyl-1,5pentanediamine and 1,3-diaminopentane chain extender, respectively, to increase the heat-set efficiency of spandex, but using such large amounts of co-extender can add to the cost of the fiber. U.S. Pat. No. 5,539,037 discloses the use of low concentrations of alkali metal carboxylates and thiocyanate in spandex to increase its heat-set efficiency. However, such salts can be removed by dissolution during fabric processing, and their effectiveness can thereby be reduced. Japanese Published Patent Applications JP07-82608, JP08-020625, JP08-176253,and JP08-176268 and U.S. Pat. Nos. 3,631,138 and 5,879,799 disclose the use of various levels of isocyanato-2-[(4′-isocyanatophenyl)methyl]benzene. The properties of spandex made from such compositions, however, do not have the desired combination of high heat-set efficiency, elongation, and unload power.
The use of substituted diisocyanates in the preparation of segmented polyurethanes for spandex has been reported. British Patent Number 1,102,819 discloses the preparation of spandex using methyl-and ethyl-substituted 4,4′-methylenebis(2,6-dimethylphyenyl)diisocyanates in combination with polytetramethyleneether glycol. The resulting “capped” glycols were then reacted with conventional chain extenders such as ethylenediamine, 2-methyl-1,5-pentamethylenediamine, propylenediamine, and the like. The polyurethaneureas prepared by this reaction, however, are insufficiently soluble to be commercially useful in making spandex by dry-spinning or wet-spinning from solution. International Published Patent Application, WO 96/05171 discloses the use of 4,4′-methylene-bis-(3-chloro-2,6-dialkylphenylisocyanates) in coatings as a less toxic replacement for toluene-2,4-diisocyanate. However, polyurethane polymers prepared from this diisocyanate and the polymeric glycols and diamine chain extenders suitable for making spandex, do not have the necessary solubility for spinning spandex from amide solvents.
There is a need for polyurethaneureas which are sufficiently soluble to be used for dry-spinning and/or wet-spinning spandex with improved whiteness retention, heat-set efficiency, and low percent set.
SUMMARY OF THE INVENTION
The present invention relates to a polyurethaneurea comprising the reaction product of a polymeric glycol, at least one Orthoalkyl-MDI, and a diamine chain extender composition comprising at least one bulky diamine. The Orthoalkyl-MDI according to the present invention are shown in Formula I:
wherein:
each R
1
may be the same or different and are independently selected from hydrogen, methyl, ethyl, propyl or isopropyl;
each R
2
may be the same or different and are independently selected from hydrogen, methyl, ethyl, propyl or isopropyl; and
each X may be the same or different and are selected from hydrogen, fluorine, or chlorine, preferably hydrogen or chlorine.
Unless otherwise indicated, as used herein the term, “Amide soluble” means that the polyurethaneurea is capable of being dissolved in at least one amide solvent to form a spinnable solution.
1,3-BAMCH refers to 1,3-bis(aminomethyl)cyclohexane;
“Bulky diamine” refers to a chain extender diamine sterically hindered at both amine groups;
1,4-DAB refers to 1,4-diaminobutane;
1,2-DACH refers to 1,2-diaminocyclohexane;
1,3-DACH refers to 1,3-diaminocyclohexane;
DCTEMDI refers to bis(2-chloro-3,5-diethyl-4-isocyanatophenyl)methane;
DEA refers to diethylamine;
DIDMMDI refers to bis(3-isopropyl-4-isocyanato-5-methylphenyl)methane;
DIMDI refers to bis(3-isopropyl-4-isocyanatophenyl)methane;
DMAc refers to N,N-dimethylacetamide;
DMDEMDI refers to bis(3-methyl-4-isocyanato-5-ethylphenyl)methane;
EDA refers to ethylenediamine;
MDI refers to 4,4′-diphenylmethane diisocyanate;
MPMD refers to 2-methyl-1,5-pentanediamine;
NPDA refers to neopentylenediamine (2.2′-dimethyl-1,3-diaminopentane);
“Orthoalkyl-MDI” refers to a diisocyanate having two or more alkyl groups of one to three carbon atoms on the positions ortho to the isocyanate groups (the 3,5-positions), optionally substituted with one or more halogens;
1,2-PDA refers to 1,2-diaminopropane;
1,3-PDA refers to 1,3-diaminopropane;
PO4G refers to poly(tetramethyleneether) glycol;
PO(4G/2Me4G) refers to poly(tetramethyleneether-co-2-methyltetramethyleneether) glycol;
“Spandex” refers to manufactured fiber in which the fiber-forming substance is a synthetic polyrner comprised of at least 85% of a segmented polyurethane (16 C.F.R. § 303.7(k), Federal Trade Commission)
TEMDI refers to bis(3,5-diethyl-4-isocyanatophenyl)methane;
TIMDI refers to bis(3,5-diisopropyl-4-isocyanatophenyl)methane; and
TMMDI refers to bis(3,5-dimethyl-4-isocyanatophenyl)methane.
DETAILED DESCRIPTION OF THE INVENTION
It has now been unexpectedly found that the whiteness retention, heat-set efficiency and percent set are improved when spandex comprises the reaction product of a polymeric glycol, at least one diisocyanate having two or more alkyl groups of one to three carbon atoms on the positions ortho to the
E.I. duPont de Nemours and Co.
Furr, Jr. Robert B.
Gorr Rachel
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