An improved spandex polymer composition provides fibers or films of the composition with increased heat set efficiency and greater discoloration resistance. The composition contains zinc oxide and a polyhydroxy additive selected from certain sugars, reduced sugars and/or polyhydroxy urethanes formed from these sugars or reduced sugars and an organic diisocyanate.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to stabilizers for spandex polymer which 
provide the polymer with improved resistance to discoloration induced by 
exposure to fumes and/or ultraviolet light. More particularly, the 
invention concerns sugars or sugar derivatives that not only provide such 
improved resistance but also provide improved heat-set efficiency to 
fibers made from the spandex polymer. 
2. Description of the Prior Art 
Spandex elastomeric fibers are made from long chain synthetic polymers 
comprised of at least 85% segmented polyurethanes. Many additives are 
known for stabilizing spandex polymers and fibers against discoloration. 
Antioxidants in the form of hindered phenols are well known and families 
of such compounds have been produced commercially under trade names such 
as "Cyanox" by American Cyanamid Co., "Irganox" by Ciba-Geigy Corp., 
"Wingstay" by Goodyear Chemical Co. "Santowhite" by Monsanto Co., 
"Ethanox" by Ethyl Corp. and the like. Additives for stabilization of the 
polymer against ultraviolet-light-induced degradation, such as "Tinuvin", 
are sold by Ciba-Geigy Corp. The addition of zinc oxide to stabilize 
spandex polymer against chlorine-induced degradation or discoloration is 
known from Martin, U.S. Pat. No. 4,340,527. Japanese Patent Application 
Publication 59-210970 discloses sucrose fatty acid esters as stabilizers 
for polyurethane compositions. Saitoh et al, U.S. Pat. No. 4,499,221 
discloses sucrose monolaurate as an optional additive to enhance the 
effect of a polymeric amine stabilizer in a polyurethane composition and 
further notes at column 6, lines 30 ff, that the composition "may further 
comprise any other conventional additive(s) such as inorganic fine powders 
(e.g., barium sulfate, titanium dioxide, silicates, zinc oxide, zinc 
sulfide), . . . ". 
The above-described stabilizers have been useful in improving the 
resistance of polyurethane polymers against discoloration induced by heat, 
ultraviolet light, fumes, chlorine and the like. However, we have found 
that other problems are encountered when sugar fatty acid esters are used 
in preparing dry-spun spandex fibers or in finishing and heat-treating 
fabrics containing such fibers. For example, when sucrose monolaurate is 
used as an additive, the spandex fibers discolor unacceptably when they 
are incorporated into a fabric which subsequently is subjected to a 
conventional heat setting treatment at a temperature between 150.degree. 
and 200.degree. C. 
It is an object of this invention to improve the utility of spandex polymer 
by enhancing its stability with additives that do not cause significant 
detrimental effect on its other physical properties or on its spinning and 
finishing characteristics when the polymer is converted into fiber. 
SUMMARY OF THE INVENTION 
The present invention provides an improved spandex polymer composition 
which contains a zinc oxide additive in a concentration of 0.5 to 10%. The 
improvement of the present invention enhances the resistance of the 
polymer to discoloration by fumes and ultraviolet light. The improvement 
comprises a polyhydroxy additive in a concentration in the range of 0.5 to 
5%, the percentages being based on weight of the polymer, the polyhydroxy 
additive being selected from the group consisting of 
sugars having the chemical formula 
EQU C.sub.x (H.sub.2 O).sub.y (I) 
where x is 4, 5, 6, 12 or 18 and y is 4, 5, 6, 11 or 16, 
reduced sugars having the chemical formula 
EQU C.sub.z H.sub.2(z+1) O.sub.z (II) 
where z is 4, 5 or 6, and 
low molecular weight polyhydroxy urethanes which are formed by the reaction 
of a large stoichiometric excess of the sugars (I) or reduced sugars (II) 
with an organic diisocyanate (i.e., excess of hydroxyl over isocyanate 
groups). The preferred concentration of the polyhydroxy additive is in the 
range of 1 to 3% and of the zinc oxide is in the range of 1 to 3%. 
Preferred polyhydroxy additives include (a) fructose or glucose, each of 
which is a sugar, (b) sorbitol or mannitol, each of which is a reduced 
sugar, and (c) the reaction product of sorbitol and tetramethylxylylene 
diisocyanate in about a 2.5:1 molar ratio. Preferred spandex polymer 
compositions also include a hindered phenolic antioxidant additive in a 
concentration in the range of 0.2 to 5%, preferably 0.5 to 3%. All 
concentrations are based on polymer weight.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
As used herein, the term "spandex" has its usual definition, as given above 
(i.e., a fiber made from a long chain synthetic polymer that comprises at 
least 85% by weight segmented polyurethane). The polyurethane has "soft 
segments" and "hard segments", which refer to specific portions of the 
polymer chain. The soft segments are the portions of the spandex polymer 
chain that can be derived from polyethers or polyesters. The hard segments 
are the portions of the spandex polymer chain that are derived from the 
reaction of an isocyanate and a diamine or diol chain extender. The 
isocyanate end group content of a polymer is referred to as NCO content. 
"Molecular weight" means number average molecular weight. "Low molecular 
weight" generally means a number average molecular weight of less than 
about 1,500. "Fiber" means staple fibers and continuous filaments. 
In accordance with the present invention, sugars of Formula I above are 
useful in providing spandex-polymer with improved resistance to 
discoloration and/or degradation induced by ultraviolet light and/or by 
fumes. The sugar contain 4, 5, 6, 12 or 18 carbon atoms, preferably 5 or 
6. The preferred 18-carbon-atom sugar is mannotriose. The preferred 
12-carbon-atom sugar is sucrose. Suitable sugars having six carbon atoms 
include fructose, glucose, galactose and the like, with fructose and 
glucose being preferred. The preferred 5-carbon-atom sugar is xylose. 
Reduced sugars (Formula II above) suitable for use in the present invention 
are prepared by reducing the aldehyde group or the ketone group of a sugar 
having five or six carbon atoms to a carbon having a hydroxyl group. A 
preferred reduced sugar having five carbon atoms is xylitol. Preferred 
six-carbon-atom reduced sugars are sorbitol and mannitol. Mannitol is 
especially preferred because of its greater resistance to extraction by 
water or cleaning solvent. 
Polyhydroxy urethanes in accordance with the invention are prepared by 
reacting an excess of a sugar of Formula (I) or reduced sugar of Formula 
(II) with an organic diisocyanate, usually in a molar ratio of at least 
1.5:1, preferably at least 1.8:1. The reaction product is a polyhydroxy 
urethane of low molecular weight having many unreacted hydroxyl groups. 
Molecular weight is usually less than 1,500. A molecular weight of less 
than 1,000 is preferred. Among the organic diisocyanates that are suitable 
for preparing the low molecular weight polyhydroxy polyurethanes are 
common commercial diisocyanates, such as hexamethylene diisocyanate 
("HMDI"), p,p'-methylene diphenyl diisocyanate ("MDI"), 
4,4'-methylene-bis(cyclohexylisocyanate) ("PICM"), isophorone diisocyanate 
("IPDI"), and .alpha.,.alpha.,.alpha.',.alpha.'-tetramethyl-m-xylylene 
diisocyanate ("mTMXDI"). The preferred diisocyanate for use in preparing 
the polyhydroxy urethanes in accordance with the invention is mTMXDI. The 
reactions between the sugars or reduced sugars with the diisocyanate can 
be carried out in the presence or absence of solvent. However, use of a 
solvent, such as dimethylacetamide or dimethylformamide, is preferred, in 
which case a mixture of reactants and solvent is heated to a temperature 
in the range of 50.degree. to 100.degree. C. until all the isocyanate 
groups have been reacted. The solvent acts as a catalyst for the reaction. 
When the reaction is carried out with only the reactants, or in a solvent 
that is not a catalyst, small amounts of catalyst, such as dibutyltin 
dilaurate, may be added or a higher temperature can be employed to 
complete the reaction. 
The polyhydroxy additives suitable for use in the present invention can 
also be employed as mixtures of the polyhydroxy additives. 
To be effective in improving the resistance of the spandex polymer to 
discoloration and degradation due to exposure to fumes and/or light, the 
sugars, reduced sugars and/or polyhydroxy urethanes in accordance with the 
invention are present in a concentration of at least 0.5% based on the 
weight of the polymer. Concentrations of 5% or higher are rarely necessary 
to obtain the desired improvements in discoloration resistance and 
heat-set efficiency. Preferred concentrations are in the range of 1 to 3%. 
In accordance with the present invention, the spandex polymer composition 
contains a zinc oxide additive. Usually, the zinc oxide is in the form of 
finely divided particles of high purity zinc oxide. Martin, U.S. Pat. No. 
4,340,527, the entire disclosure of which is hereby incorporated herein by 
reference, describes such zinc oxide particles as being useful for 
improving the chlorine resistance of spandex fibers. Zinc oxide in the 
spandex polymer composition of the present invention greatly enhances the 
effect of the polyhydroxy additive in increasing the resistance of the 
spandex polymer to discoloration on exposure to fumes and/or ultraviolet 
light. Preferably, the zinc oxide has a purity of at least 99.4%, most 
preferably 99.7%, and is present in the spandex polymer in a concentration 
in the range of 0.5 to 10%, preferably 1 to 3%, by weight of the spandex 
polymer. An indication of zinc oxide purity is provided by its sulfur 
content. The high purity zinc oxide for use in the spandex polymer 
compositions generally has a sulfur content of no greater than 0.025% and 
preferably no greater than 0.005 %. 
In accordance with a preferred embodiment of the present invention, the 
polyhydroxy additive (i.e., sugar, reduced sugar and/or polyhydroxy 
urethane) and the zinc oxide additive are employed in the spandex polymer 
in combination with a hindered phenolic antioxidant. Hindered phenolic 
antioxidants are well known in the art and include, for example: 
1,3,5-tris(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6(1H, 
3H,5H)trione ["Cyanox" 1790 sold by American Cyanamid Co.]; 
1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene 
["Ethanox" 330 sold Ethyl Corp.]; 
1,1-bis(2-methyl-4-hydroxy-5-t-butylphenyl)butane ["Santowhite" powder sold 
by Monsanto Co.]; 
a condensation product of p-cresol, dicyclopentadiene and isobutene 
["Wingstay" L sold by Goodyear Chemical Co.]; 
and the like. 
The concentration of the phenolic antioxidant in the spandex is usually in 
the range of 0.2 to 5%, preferably 0.5 to 2%, based on the weight of the 
spandex polymer. 
Surprisingly, spandex polymer containing zinc oxide and polyhydroxy 
additives in accordance with the invention has a much greater resistance 
to discoloration than would have been expected from discoloration testing 
of spandex polymer samples that contained only one or the other of the 
carbohydrate or the zinc oxide. This combination of polyhydroxy additive 
and zinc oxide is believed to give a synergistic protection to the spandex 
polymer against discoloration. The improved resistance to discoloration 
persists even after fibers or films made with the spandex polymer 
composition have been scoured in an aqueous bath that would have been 
expected to remove the usually water-soluble sugars from the polymer. It 
was also surprising that these polyhydroxy additives proved to be highly 
non-extractable in aqueous and solvent baths of the type that fabrics made 
with spandex fibers usually are subjected to during commercial scouring 
and dyeing operations. 
Conventional methods can be employed for adding the stabilizers and 
additives of the invention to the spandex polymer. For example, a 
concentrated slurry solution of the additives can be prepared in the same 
solvent as is used to prepare the spandex spinning solution. The 
concentrated slurry or solution can be added to the polymer solution prior 
to forming the polymer into articles, such as fibers or films. 
The improved spandex polymer compositions of the invention are made from 
segmented polyurethanes, such as those based on polyethers, polyesters, 
polyesterethers and the like. Such spandex polymers are well known and can 
be prepared by methods such as those disclosed in U.S. Pat. Nos. 
2,929,804, 3,097,192, 3,428,711, 3,533,290, and 3,555,115, among others. 
The compositions of the invention are most useful in polyether-based 
spandex. 
The spandex polymer compositions of the invention may also contain a 
variety of other additives for other purposes. Among these other additives 
can be pigments or delustrants such as titanium dioxide, anti-tack agents 
or lubricants such as magnesium stearate and calcium stearate, whiteness 
enhancers such as ultramarine blue, dye enhancers such as DIPAM/DM (a 
copolymer of diisopropylaminoethyl methacrylate and n-decyl methacrylate), 
fillers such as talc, and the like, provided that the additional additives 
do not interfere with or detrimentally affect the polyhydroxy and zinc 
oxide additives required by the invention. 
TEST PROCEDURES 
The following procedures are used for measuring the various properties and 
parameters reported herein. 
PREATION OF TEST SAMPLES 
To determine the suitability of an additive for increasing the resistance 
of the spandex polymer to discoloration, samples of filaments and/or films 
of the polymer containing the additives are prepared for exposure tests. 
For the film samples, a polymer solution is prepared substantially as 
described in the first paragraph of Example 1, below. Then, 220 grams of 
the polymer solution is thoroughly mixed with 20 grams of 
N,N-dimethylacetamide solvent containing the desired amount of test 
additive (e.g., 0.84 grams for 1% of additive based on the weight of the 
polymer). The polymer solution with additives is then allowed to remain 
undisturbed for 30 minutes. Then, films are cast on a "Mylar" polyester 
sheet. A doctor knife apparatus having a 0.020-inch (0.051-cm) wide gap is 
employed. Test samples measuring about 8 inches by 3.5 inches (20.3 cm by 
8.9 cm) of N,N-dimethylacetamide solution are cast. After the cast films 
have been air-dried for 24 hours, the test samples are stripped from the 
"Mylar" sheet. 
To prepare fiber samples, polymer solutions are prepared first in the same 
manner as described in the preceding paragraph. The required amount of 
additive (in N,N-dimethylacetamide) is added to the spinning solution and 
thoroughly mixed. Then the solution is dry-spun by conventional techniques 
into yarns of 40 or 70 denier (44 or 78 dtex). A test sample of the yarn 
is formed by winding the yarn at low tension on an aluminum card measuring 
3 inches by 4 inches by 1/16 inch (7.6 cm.times.10.2 cm.times.0.16 cm) to 
give a layer of about 1/8-inch (0.32-cm) thickness. 
After the film and yarn samples have been prepared, the samples are scoured 
in a solvent and/or aqueous bath. To simulate a solvent scouring bath, the 
film samples are immersed in 150 cm.sup.3 of "Perclene" 
tetrachloroethylene (sold by Diamond Shamrock Chemical Co., Irving, Tex.) 
for 30 minutes with occasional stirring and then dried in air for 4 hours 
before being "boiled off" (i.e., immersed in boiling water for 30 minutes) 
and used for testing. To simulate an aqueous scouring bath, the samples 
are immersed for an hour in a 80.degree.-to-85.degree. C. bath containing 
two liters of water in which are 8 grams of "Duponol" EP surface active 
agent (diethanolamine lauryl sulfate made by E. I. DuPont de Nemours and 
Company), 5 grams of tetrasodium pyrophosphate and 1.5 grams of ethylene 
diamine tetra-acetic acid. After removal from the bath, the samples are 
rinsed repeatedly in clear water until no trace of the bath additives is 
detectable in the rinse water. 
DISCOLORATION MEASUREMENTS 
Change in color of test samples is determined by the change in "b" values, 
which are measured by means of a differential color meter (Hunter Lab 
Color Quest 45/0, manufactured by Hunter Associates Laboratory, Inc., of 
Reston, Va.). The "b" values of samples before and after exposure are 
measured and the difference is reported as ".DELTA.b". Differences in 
.DELTA.b values are reported herein as .delta.(.DELTA.b) values. 
RESISTANCE TO DISCOLORATION BY FUMES AND LIGHT 
Resistance of a spandex sample to discoloration on exposure to nitrogen 
dioxide and ultraviolet light is measured with sample yarns wound on 
aluminum plates or on extracted/scoured film samples replaced on "Mylar" 
polyester film. The samples are exposed in a Scott Controlled Atmospheric 
Tester (SCAT). A flow of 2,760 cm.sup.3 of air and 42 cm.sup.3 of NO2 per 
minute is maintained while exposing the samples to light from a "daylight" 
fluorescent tube and four "black" fluorescent tubes (type F 30T8 and F 
30T8 BL, respectively, made by General Electric Company). The SCAT tester 
is described in Technical Bulletin L-33 (published by the Textile Fibers 
Department Technical Service Section of E. I. DuPont de Nemours & Company, 
Wilminton, Del.). In the Examples below, this test is referred to as the 
"NO.sub.2 /UV" test. 
RESISTANCE TO ULTRAVIOLET LIGHT 
To measure the resistance of spandex samples to discoloration on exposure 
to ultraviolet light alone, samples are exposed for 20, 40 and 60 hours in 
an Atlas Ci65 weather-o-meter. In the Examples and Tables below, this test 
is referred to as the "UV" test. 
HEAT SET EFFICIENCY (HSE) 
The ability to heat set a spandex sample is determined by measuring its 
heat set efficiency. In this test, six yarn samples, or six 1/8-inch 
(0.32-cm) wide film samples, are placed on a frame, drafted to 1.5 times 
their original length and then heated for 90 seconds at 195.degree. C. The 
yarns, in a relaxed condition, are then immersed in boiling water for 30 
minutes. This treatment in boiling water is sometimes referred to herein 
as a "boil off". The % HSE is defined as 100 times the final average 
length increase of the samples divided by one-half the initial length. 
Thus, 
EQU % HSE=100(L.sub.f -L.sub.i).div.0.5L.sub.i, 
where L.sub.f is the final length and L.sub.i is the initial length of the 
sample. 
The invention is further illustrated by the following examples of preferred 
embodiments. These examples are included for the purposes of illustration 
and are not intended to limit the scope of the invention, which is defined 
by the appended claims. The reported results are believed to be 
representative, but do not constitute all the runs involving the indicated 
ingredients. In the examples, samples of the invention are designated with 
arabic numerals and comparison samples are designated with upper case 
letters. 
EXAMPLE 1 
This example demonstrates a clear advantage in resistance to 
fume-and-light-induced discoloration and in heat set efficiency of spandex 
fiber containing zinc oxide and a preferred reduced sugar additive 
according to the invention (Sample 1) over the same fiber from which the 
reduced sugar is omitted (Sample A). 
A solution of segmented polyurethane in N,N-dimethylacetamide was prepared 
in accordance with the general procedure described in U.S. Pat. No. 
3,428,711 (e.g., first sentence of Example II and the description of 
Example I). An intimate mixture was prepared of p,p'-methylenediphenyl 
diisocyanate and polytetramethylene ether glycol (about 1800 molecular 
weight) in a molar ratio of 1.63 and was held at a temperature of about 
80.degree. to 90.degree. C. for 90 to 100 minutes to yield an 
isocyanate-terminated polyether (i.e., a capped glycol having 2.40% NCO 
content) which was then cooled to 60.degree. C. and mixed with 
N,N-dimethylacetamide to provide a solution containing about 45% solids. 
Then while maintaining vigorous mixing, the capped glycol was reacted for 
2 to 3 minutes at a temperature of about 75.degree. C. with diethylamine 
and a 90/10 molar ratio of ethylenediamine and 1,3-cyclohexylenediamine 
chain extenders. The molar ratio of diamine chain extender to diethylamine 
was 6.3 and the equivalent ratio of diamine chain extenders to unreacted 
isocyanate in the capped glycol was 0.948. The resultant solution of 
segmented polyurethane contained approximately 36% solids and had a 
viscosity of about 2100 poises at 40.degree. C. 
Additives were dispersed in dimethylacetamide solvent and then thoroughly 
mixed with the polymer solution to give concentrations of 3% zinc oxide, 
2% of DIPAM/DM (a 75/25 copolymer of diisopropylaminoethyl methacrylate 
and n-decyl methacrylate), 1.5% "Cyanox" 1790 hindered phenolic 
antioxidant (2,4,6-tris(2,6-dimethyl-4-t-butyl-3-hydroxybenzyl)isocyanurat 
e), 0.01% silicone oil and about 1.5% sorbitol in the final fiber (without 
finish). All concentrations are based on the weight of the spandex 
polymer. 
The above-described mixture and a mixture without sorbitol were dry spun 
through orifices in a conventional manner to form coalesced 4-filament, 
40-denier yarns. The yarn containing sorbitol in accordance with the 
invention was designated Sample 1, and the comparison yarn with no 
sorbitol was Sample A. A surface lubricating finish of 91% polydimethyl 
siloxane, 5% polyamylsiloxane and 4% magnesium stearate was applied to the 
yarn. The yarn was wound on a plastic-coated cardboard tube. Test samples 
were rewound on aluminium cards and scoured in "Perclene" and aqueous 
baths. The changes in color (.DELTA.b) of the samples due to exposure in 
the NO.sub.2 /UV and UV testers are summarized in Table I. 
The data in Table I demonstrate that the presence of a 1.5% concentration 
of sorbitol in the fiber drastically reduces light-induced discoloration 
in samples that had been scoured in solvent ("Perclene") or aqueous baths. 
In addition, the presence of sorbitol apparently provided a substantial 
increase in heat set efficiency. 
TABLE I 
______________________________________ 
Sample 1 Comparison A 
______________________________________ 
Of Invention yes no 
% HSE 78.1 66.6 
Scouring bath 
Solvent Water Solvent 
Water 
Color changes, ".DELTA.b" 
40-hour NO.sub.2 /UV test 
9.4 8.7 15.0 12.7 
40-hour UV test 
4.5 5.3 8.0 9.9 
______________________________________ 
EXAMPLE 2 
This example illustrates the superior heat set efficiency and discoloration 
resistance of spandex polymer containing reduced sugars in accordance with 
the invention over such polymer in which a simple aldehyde is used instead 
of the reduced sugar. 
Polymer solution was made as described in Example 1. Zinc oxide, DIPAM/DM 
and "Cyanox" 1790 were added to the solution in concentrations of 3%, 2% 
and 1.5%, respectively, based on the weight of the polymer. Another test 
additive was added to the polymer solution in a 2% concentration. 
Aldehydes and sugars were tested. Films were cast of the thusly prepared 
solutions and then given a solvent scour before testing. 
Glyceraldehyde and malonaldehyde were found to discolor the solution during 
mixing; simple aldehydes did not reduce discoloration in the NO.sub.2 /UV 
test. In contrast, each of the tested aldoses, ketose and reduced sugar 
improved heat set efficiency and reduced discoloration in the 48-hour 
NO.sub.2 /UV exposure test. In addition, it was found that simple sugars 
improved whiteness retention more than did corn syrup (a mixture of six 
and 12 carbon sugars). Test results are summarized in Table II. 
TABLE II 
______________________________________ 
Test Initial 
NO.sub.2 :/UV 
Sample 
Additive % HSE "b" ".DELTA.b" (48 hr) 
______________________________________ 
2 xylose 89.1 0.5 1.7 
(aldopentose) 
3 mannose 89.1 1.3 2.2 
(aldohexose) 
4 fructose 89.0 3.3 1.1 
(ketohexose) 
5 sorbitol 87.3 2.6 0.8 
(reduced hexose) 
6 corn syrup 87.4 1.5 2.9 
(mixed sugars) 
B glyceraldehyde 
87.6 35.2* * 
(aldotriose) 
C butyraldehyde 
84.5 1.9 5.9 
D malonaldehyde 
84.4 9.4* * 
bis-diethylacetal 
E no test additive 
83.6 1.4 5.4 
______________________________________ 
*Samples highly discolored. 
EXAMPLE 3 
This example shows the effect of corn syrup additive concentration on heat 
set efficiency and compares it to the the effect of a starch additive. For 
these tests, film samples were prepared as in Example 2, except that the 
concentration of sugar was different or starch replaced the sugar. The 
test results which are summarized in Table III show that, within the range 
of concentrations tested, (1) higher sugar concentrations generally lead 
to greater improvements in heat set efficiency and (2) starch additive has 
no positive effect on heat set efficiency. 
TABLE III 
______________________________________ 
% carbohydrate Heat Set Efficiency, % 
Concentration Syrup Starch 
______________________________________ 
0.0 83.7 83.7 
0.5 85.9 83.8 
1.0 86.7 84.0 
2.0 88.0 81.5 
4.0 87.7 82.8 
______________________________________ 
EXAMPLE 4 
This example further illustrates the effectiveness of sugars and reduced 
sugars in improving the heat set efficiency and discoloration of spandex 
polymers containing additives in accordance with the invention. 
Film samples were prepared as in Example 2 except that the polyhydroxy 
additives of the invention differed from those of Example 2 or were 
comparison additives outside the invention. The concentration of the test 
additive was 2% based on the weight of the polymer. Table IV summarizes 
the results. Note that glycerol and pentaerythritol (Comparison Samples G 
and H, respectively) provided no significant protection against UV-light 
induced discoloration and had no effect on or were detrimental to heat set 
efficiency. Samples of the invention containing glucose (7), dl-threitol 
(10), xylitol (11) and mannitol (12) provided good protection against 
discoloration and high heat set efficiency. Of these, mannitol provided 
the highest heat set efficiency. 
TABLE IV 
______________________________________ 
Effect of Sugar and Reduced Sugars on 
Light Stability and % Heat-set Efficiency 
".DELTA.b"* 
Percent NO.sub.2 /UV 
UV 
Test Sample HSE 40 hrs 80 hrs 
______________________________________ 
F. No polyhydroxy additive 
86.1 2.6 13.9 
7. d-glucose (monosaccharide) 
92.1 1.9 10.6 
8. Sucrose (disaccharide) 
91.1 2.4 11.3 
9. Maltotriose (trisaccharide) 
89.1 2.6 13.1 
10. dl-threitol (4-C polyol) 
87.6 0.9 9.9 
11. xylitol (5-C polyol) 
88.9 1.0 9.5 
12. mannitol (6-C polyol) 
92.5 0.8 10.6 
G. glycerol (3-carbon polyol) 
85.9 2.0 13.6 
H. pentaerythritol (4 primary 
** 2.2 13.8 
hydroxyls) 
______________________________________ 
*Color data after "Perclene" scour. 
**Yarn broke in testing. 
EXAMPLE 5 
This example illustrates the advantageous use of typical hindered phenol 
antioxidants in combination with a sugar additive and zinc oxide in 
accordance with the invention. 
Films were prepared as described in Example 2, with the additives of 
Example 2 except that the specific polyhydroxy additives and hindered 
phenol antioxidants listed in Table V were used in place of such additives 
of Example 2. The antioxidants listed in the table are (a) for comparison 
I and sample 13, "Cyanox" 1790, which is 
1,3,5-tris(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6(1H 
,3H,5H)trione, (b) for comparison J and samples 14-15, "Santowhite" Powder 
which is 1,1-bis(2-methyl-4-hydroxy-5-t-butyl-phenyl)butane and (c) for 
comparison K and sample 16, "Wingstay" L, which is a condensation product 
of p-cresol, dicyclopentadiene and isobutene. 
Table V shows that xylose and sorbitol in combination with zinc oxide are 
very effective in reducing light-induced discoloration in films containing 
"Santowhite" SWP and "Wingstay" L. 
TABLE V 
______________________________________ 
Test with Various Antioxidants 
(.DELTA.b) 
NO.sub.2 /UV 
UV 
Sample 
Test Additives HSE 40 hrs 80 hrs 
______________________________________ 
I 1.5% Cyanox 79.7 5.1 12.6 
13 1.5% Cyanox + 2% xylose 
82.1 0.8 8.9 
J 1% SWP 81.3 9.1 10.7 
14 1% SWP + 2% xylose 
83.3 1.4 4.8 
15 1% SWP + 2% sorbitol 
87.0 1.3 3.9 
K 1% Wingstay 81.2 7.0 12.9 
16 1% Wingstay + 2% xylose 
84.6 0.6 7.4 
______________________________________ 
Notes: 
All samples contain 3% ZnO and 2% DIPAM/DM (75/25). 
.DELTA.b is measured after "Perclene" scour. 
All % concentrations are by weight of the polymer. 
Cyanox is "Cyanox" 1790. 
SWP is "Santowhite" powder. 
Wingstay is "Wingstay" L. 
Tests, similar to those reported in the preceding paragraphs of this 
example, were performed with corn syrup as the polyhydroxy additive 
additive. "Cyanox" 1790, "Permanax" W80 (a high molecular weight phenolic 
antioxidant) and "Permanax" WSL antioxidant (a derivative of 
4,6-dimethylphenol), the latter two antioxidants being sold by Vylnax, 
were employed as phenolic antioxidants. As shown by the results summarized 
in Table VI, polyhydroxy additives in combination with zinc oxide results 
in a large reduction in light-induced discoloration, even with Permanax 
antioxidants which usually were found to be among the phenolic 
antioxidants that were less effective than "Cyanox" for spandex fibers and 
films. 
TABLE VI 
______________________________________ 
Light Protection with Other Antioxidants 
Sam- 48-hour NO.sub.2 /UV (.DELTA.b) 
ple Test Additives Not Scoured 
Scoured 
______________________________________ 
L 1.5% Cyanox 7.2 7.7 
17 1.5% Cyanox + 2% corn syrup 
4.2 3.5 
M 1% WS0 15.0 12.3 
18 1% WS0 + 2% corn syrup 
6.6 4.3 
N 1% WSL 7.6 10.7 
19 1% WSL + 2% corn syrup 
6.0 5.4 
______________________________________ 
Notes: 
All samples contain 3% ZnO and 2% DIPAM/DM (75/25). 
Scour refers to a "Perclene" scour. 
All % concentrations are by weight of the polymer. 
Cyanox is "Cyanox" 1790. 
WS0 is "Permanax" WSO. 
WSL is "Permanax" WSL. 
EXAMPLE 6 
The beneficial effect of the combined zinc oxide and polyhydroxy additives 
in accordance with the invention in improving light stability is 
demonstrated by this example. Samples of 8-filament, 70-denier spandex 
fiber yarns, containing 1.5% "Cyanox" 1790, 2% DIPAM/DM and various 
concentrations of titanium dioxide (TiO.sub.2) and zinc oxide (ZnO) 
particles, with or without a 2% concentration of sorbitol additive, were 
prepared by the general procedure of Example 1. The results of light 
exposure tests of the samples are summarized in Table VII. The results 
show that TiO.sub.2 does not have much effect on light discoloration in 
contrast with ZnO which provides a significant improvement. 
TABLE VII 
______________________________________ 
Effects of TiO.sub.2 and ZnO and Sorbitol on Light Stability 
.DELTA.b 
Percent Pigment Initial 20-hr. 40-hr. 
Sample 
TiO.sub.2 
ZnO Total "b" NO.sub.2 /UV 
UV 
______________________________________ 
O 5 0 5 -0.2 5.5 3.0 
P* 5 0 5 -0.2 5.1 2.9 
.delta.(.DELTA.b) 
= -0.4 -0.1 
Q 4 1 5 0.1 5.7 3.6 
20* 4 1 5 0.1 5.3 2.4 
.delta.(.DELTA.b) 
= -0.4 -1.2 
R 3 2 5 -0.1 6.9 3.6 
21* 3 2 5 -0.1 4.3 2.2 
.delta.(.DELTA.b) 
= -2.6 -1.4 
S 1 3 4 -0.8 7.6 4.0 
22* 1 3 4 -0.8 4.5 2.4 
.delta.(.DELTA.b) 
= -3.1 -1.6 
T 0 3 3 -0.7 6.7 5.1 
23* 0 3 3 -0.7 4.7 2.9 
.delta.(.DELTA.b) 
= -2.0 -2.2 
U 0 2 2 -0.5 7.7 6.0 
24* 0 2 2 -0.5 7.1 4.8 
.delta.(.DELTA.b) 
= -0.6 -1.2 
V 0 1 1 -1.5 9.3 7.4 
25* 0 1 1 -1.5 6.7 6.6 
.delta.(.DELTA.b) 
= -2.6 -0.8 
W 0 0 0 -0.8 6.7 10.3 
X* 0 0 0 -0.8 9.9 12.2 
.delta.(.DELTA.b) 
= +3.2 +1.9 
______________________________________ 
Notes: 
*Sample contains 2% sorbitol. 
Color data were obtained on samples that had been subjected to an aqueous 
scouring. 
.delta.(.delta.b) = difference in .delta.b between sample with and sample 
without sorbitol added. 
EXAMPLE 7 
This example shows the superior heat-set efficiency and discoloration 
resistance of spandex polymer containing polyhydroxy urethane additives in 
accordance with the invention over such spandex polymer without the 
polyhydroxy additive. 
Polyhydroxy urethanes were prepared by reacting sorbitol in 
dimethylacetamide solution with different diisocyanates, in about a 2:1 
mole ratio of sorbitol to diisocyanate, until the presence of unreacted 
isocyanate groups could no longer be detected. The polyhydroxy urethane 
products of the reactions were added to a spandex polymer spinning 
solution at a 1% concentration along with concentrations of 3% zinc oxide, 
2% DIPAM/DM and 1.5% Cyanox.RTM. 1790, all the percentages being based on 
weight of spandex polymer. Spandex yarns of 44 dtex were then dry spun as 
described in Example 1. Results of exposure tests of the spun yarns are 
summarized in Table VIII. As shown by the Table VIII, Samples 26-30 of the 
invention had much better heat-set efficiency and discoloration resistance 
than Comparison Sample Y, which contained no polyhydroxy additive. 
TABLE VIII 
______________________________________ 
Effect of Polyhydroxy Urethane Additive 
Derived from Sorbitol and Organic Diisocyante on 
% HSE and Discoloration Resistance 
Discoloration ".DELTA.b" 
Test Diiso- % Perclean Scour 
Aqueous Scour 
Sample 
cyanate* HSE+ NO.sub.2 /UV 
UV NO.sub.2 /UV 
UV 
______________________________________ 
26 PICM 81.5 5.8 7.0 5.7 8.4 
27 IPDI 81.5 4.7 7.2 6.6 8.4 
28 mTMXDI 83.0 6.6 6.1 5.7 8.4 
29 MDI 82.0 7.1 5.9 6.7 8.4 
30 HMDI 82.0 7.8 6.9 4.9 9.1 
Y ** 79.5 8.2 8.0 7.9 10.1 
______________________________________ 
Notes 
*Definition of diisocyanate abbreviations 
PICM = 4,4'-methylenebis(cyclohexyl) diisocyanate 
IPDI = isophorone diisocyanate 
mTMXDI = .alpha.,.alpha.,.alpha.',.alpha.'-tetramethylxylylene 
diisocyanate 
MDI = p,p'-methylenediphenyl diisocyanate 
HMDI = hexamethylene diisocyanate 
+Sample heat set for 120 seconds, instead of 90 sec. 
**Comparison sample; contains no polyhydroxy urethane 
The results summarized in the preceding examples demonstrated the 
beneficial effects on UV-light resistance, fume resistance and heat set 
efficiency which result from adding a combination of polyhydroxy additives 
and zinc oxide to a spandex in accordance with the present invention. 
Although the inclusion of polyhydroxy additives (without zinc oxide) in 
spandex films and fibers can reduce UV-light-induced discoloration 
somewhat, the effect is much greater in the presence of zinc oxide. The 
combination also provides much more discoloration resistance than does 
zinc oxide (without polyhydroxy additive). Surprisingly, the improved 
discoloration resistance was retained even after the fiber or film had 
been subjected to an aqueous scour which would have been expected to 
remove the usually water-soluble sugars. This greatly enhances the utility 
of the invention because aqueous treatments, such as dyeing and scouring, 
are often employed with fabrics that contain spandex fibers. The results 
also showed that (a) monosaccharides perform better than polysaccharides, 
(b) six-carbon sugars perform much better than three-carbon compounds, and 
(c) reduced sugars, such as sorbitol or mannitol, and their urethane 
derivatives are preferred.