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Патент USA US3077016

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Feb. 12, 1963
s. M. lBRAHlM I
3,077,006
PRODUCTION OF STAPLE FIBERS
Filed Oct. 30. 1961
INVENTOR
SALIM M. IBRAHIM
ATTORNEY
,
United States Patent“ 0 "ice
senses
Patented Feb. 12, l???
31 .
$377,696
PRGDUQ'HQN all? S'IAQLE ll'ii?ERr-‘S
Salim M. Ibrahim, Wilmington, Deb, ass.‘ nor to E. i.
du Pont de Nemours and Company, ‘Wilmington, Bela,
a corporation of Delaware
Filed
36, mm,
No. lli???ii
ii laims. (ill. iii-.48}
tie or initial modulus, e.g., from 4 to 100 grams per
denier ‘or greater.
The invention will be more fully understood by refer
ence to the accompanying drawing in which the ?g
ore is ‘a side view of a schematic representation of ap
paratus for converting the ?laments to staple ?bers.
Referring now to the ?gure, reference letters A
and A’ represent ?at sheets or tows of inelastic ?laments
and reference letter B represents a flat sheet of con
This invention relates to a method for preparing blends
of staple ?bers from continuous elastic ?laments and 10 tinuous elastic ?laments. The inelastic ?laments A are
passed over tension bars til, 12, id, ‘and to to a pair
inelastic laments. More particularly, this invention re
of input feed rolls 33 and at}. Simultaneously the
lates to a method for converting continuous elastic ?la~
elastic ?laments E are passed over a tension bar 13, be
ments and inelastic ?laments into staple fiber which may
tween two pairs of feed rolls 2?-—22 and 26-23- and
be processed into slivers of intermingled elastic and
inelastic staple fibers which may be subsequently pro 15 forwarded in a stretched condition to the input feed rolls
38 and so. At the same time, inelastic ?laments A’
cessed into high quality stretchable yarns and stretchable
are passed over tension bars 3th 3-2, 34- and 36 to the input
fabrics by utilizing known processing equipment.
feed rolls 33 and 4th in delivering the elastic ?laments
ethods for preparing blended sliver from two or
E to the input feed rolls 3t} and 4d, a predetermined
more different kinds of inelastic continuous ?laments are
well known. However, the application of these methods 20 amount of stretch is imparted to the ?laments by driv
ing feed rolls 26—2% at a higher linear surface speed
to ‘the preparation of blended sliver from continuous
elastic ?laments and inelastic ?laments has not proved
to be satisfactory. After cutting the elastic ?bers to staple
than feed rolls 2t‘l—--22. This stretch is maintained by
input feed rolls 38‘ and lit), at which point the sheets
of inelastic ?laments A and A’ are combined into a com
lengths, they tend to remain in tightly formed clumps that
resist separation in the blending with inelastic staple 25 posite web with the sheet of elastic ?laments E. The
composite web is forwarded by the input feed rolls 38
?bers and cause such crinkling and wrinkling of the ?ber
sheet ‘as to render it totally unprocessable.
and so to fracturing rolls 42. and 44 where the con
it is, therefore, an object of this invention to provide
an improved method for preparing blends of staple ?bers
from continuous elastic ?laments and inelastic ?laments.
It is another object of this invention to provide a method
for preparing blended sliver from continuous elastic ?lo
tinuous ?laments are cut to staple ?ber length. The staple
?bers are picked up by pick-up rolls 45 and 43 and may
ments and inelastic ?laments which permits the use of
be forwarded directly to a suitable container 52 as cut
?ber ‘or processed to sliver form S by suit-able apparatus
‘Eli.
As previously indicated, the stretching of elastic ?la
inafter.
The objects of this invention are achieved by a method
ments B may be accomplished by driving feed rolls
2l?—2? at a higher linear surface speed than feed rolls
Edi-22. Unless some appreciable stretch, e.g., at least
about 2%, is imparted to the elastic ?laments, the cut
bers tend to form tight clumps that resist distribution
in the blend and cause such severe crinkling and wrinkling
in the cut ?ber sheet as to make it totally unprocessable.
Generally it is preferred that the elastic ?laments E be
which comprises ?rst forming a plurality of separated
stretched an amount from about 5% to about 15%
conventional equipment for converting such ?laments into
sliver form. A further object of this invention is to
provide a method whereby continuous elastic ?laments
‘and inelastic ?laments are simultaneously cut to staple
lengths whereby the elastic ?bers have a high degree of
length uniformity. Other objects will be apparent here
greater than their relaxed length; however, it has been
flat sheets of continuous elastic ?laments and inelastic
found that little advantage is gained in processability or
?laments. The sheets ‘of elastic ?laments are tcnsioned
to stretch the ?laments a predetermined amount beyond 45 cut length uniformity at stretch levels much above 15%.
Some tension should also be applied to the inelastic
their normal relaxed length. After the tensioning step,
?laments. This tension should, of course, be sufficient
the elastic ?laments are combined in layered relationship
to maintain a uniformly flat sheet. Tensions which
with the inelastic ?laments to form a composite web
stretch or deform the inelastic ?laments should generally
in which the sheets of tensioned elastic ?laments lie
between adjacent sheets of inelastic ?laments. ‘Without 50 be avoided.
in practicing the present invention, particularly desir
permitting the elastic ?laments to retract, the composite
able results have been obtained by flexing the elastic ?la
web is fed to fracturing means where the ?laments are
merits E before formation of the composite web, e.g., as
cut to staple length. Surprisingly, the elastic staple ?bers
they pass between the two sets of feed rolls during the
thus prepared are found to be of uniform length, and the
tensioning step. Referring again to the ?gure, an os~
blend of elastic and inelastic ?bers exhibits excellent
cillating roll 24 may be positioned between the two sets
processability in the subsequent steps of converting the
of feed rolls 243-22 and 26-213 to stretch the elastic
?bers to sliver and ultimately to yarn form.
?laments from about 2 to about 5 times, preferably about
By the term “elastic ?laments and ?bers" it is meant
3.5 times, their relaxed length during the tension step.
synthetic and natural ?laments and ?bers having a high
Alternatively, the elastic ?laments may be flexed before
brealdng elongation, e.g., 109% or more and preferably
entering the stretching zone. One cycle of stretching and
5 00% to 800%, and a low elastic or initial modulus, e.g.,
relaxing
is generally all this required; however, additional
less than one gram per denier, preferably 0.08 gram per
cycles may be used. It is, of course, necessary in all cases
denier or lower, and exhibit a quick and substantially
that the elastic ?laments be in the previously described
complete recovery from stretching to an amount less than
stretched condition of from about 2% to about 15% and
their breaking elongation, e.g., have a tensile recovery
sandwiched between layers of inelastic ?bers when fed to
of about 90% or more and a stress decay of less than
the fracturing rolls.
about 20%.
After fracturing the ?laments, the staple ?bers may, as
By the term “inelastic ?laments and ?bers” it is meant
previously indicated, he directed into a suitable receptacle
those natural and synthetic ?bers which generally have 70 or preferably processed immediately into top, sliver, batts, .
ya as, fabrics, and other textile forms using conventional
a breaking elongation of less than about 100% and, as
processing machinery. The fracturing step with the sub
compared to the elastic ?bers, have a relatively high elas
3,077,006
sequent steps of aligning the ?bers to form a web and
drafting the web and rolling the drafted staple ?bers into
a helical roll or sliver are conveniently achieved using
equipment described in U.S. 2,438,469, which is com
monly known as the “Paci?c Converter.” The equipment
described in U.S. 2,748,426, known as the “Turbo
Stapler,” may also be used. Because of the signi?cant
di?erence in break elongations of the elastic and inelastic
?bers in the composite web, less satisfactory results are
achieved on systems which depend on breaking the ?bers 10
of hydrazine (35% in water) and diethylamine (5% in
dimethylformamide) in the ratio of 37.5 parts of hydra
zine to 1 part of diethylamine is added as a single stream
at a rate of 0.465 pound per hour with strong agitation.
The mixture passes to a reaction chamber held at a tem'
tively long, '.e., from about 3.0 to 6.0 inches, although
both longer and shorter lengths may be prepared by the
perature of 20—40° C., the contents having residence time
of about 2-3 minutes. The emerging polymer solution
contains approximately 17.7% solids and has a viscosity
of 700 poises at 30° C. To the polymer solution are
added a slurry of titanium dioxide in dimethylformamide
a solution of poly(N,N-diethyl-beta-aminoethyl methac
rylate) in dimethylformamide and a solution of 4,4'-bu
tylidenebis-(6-t-butyl-m - cresol) in dimethyl?ormamide,
such that the ?nal mixture contains 5%, 5%, and 1%,
respectively, of each additive based on the polyurethane.
This solution is then extruded through a 960-l1ole
spinneret (ori?ce diameter 0.0025 inch) into an aqueous‘
method described herein.
bath containing 50% dirnethylformamide and 5-1 0% talc,
by stretching rather than fracturing. Other apparatus
such as the variable cutter attachment for the Paci?c
Converter described in U.S. 2,599,148 may be utilized.
Most advantageous results are obtained when the elastic
?ber component is cut to uniform lengths which are rela
If it is desired to utilize in
elastic ?laments of signi?cantly shorter lengths, it is within
and maintained at about 95° C. The 6,000-denier tow
the scope of the present invention to utilize, as the sheet 20 thus formed is removed at about 40-50 yards per minute
of inelastic ?laments, natural or synthetic staple ?bers in
and passed through a water bath maintained at 90° C. to
sliver or web form.
95° C. until the ?laments contain less than 0.5% dirneth
From a practical viewpoint, the commercially avail
ylformamide. After application of a talc ?nish, the tow is
able apparatus for converting continuous ?laments directly
dried in a relaxed condition for three hours at 104° C.
to sliver, i.e., the tow-to-top conversion systems widely 25 and then heated for 45 minutes at 140° C. The spandex
used in the textile industry, are designed to operate on
tow thus produced has an individual ?lament denier of 6
tow bundles of 1.5 to 2 million total denier. In addition,
and total tow denier of approximately 6,000.
the inelastic ?bers are commercially available in tows of
(12) Preparation of Composite Tow
from 200,000 to 500,000 total denier. Since it is a re
quirement of the present invention that the elastic ?la 30
The spandex tow is used to prepare a composite tow
rnents be sandwiched between the layers of inelastic ?bers,
the inelastic ?bers will generally account for a minimum
of one-half to one million denier or approximately one
fourth to one-half the capacity of the conventional appa
comprising about 10% by Weight of the spandex tow
and about 90% by Weight of a commercially available
inelastic acrylonitrile polymer ?ber tow. The inelastic
tow has a ?lament denier of 3 and a total tow denier of
ratus. Thus, from a practical standpoint, the elastic ?la~
470,000. Referring to the apparatus illustrated in the
ment content of the composite tow will have as its upper
drawing, one end of the inelastic tow is spread out to
limit approximately 50 %to 80% of the total ?ber weight.
Preferably, the elastic ?laments will comprise from about
form a wide sheet A and two ends of inelastic tow are
spread similarly to form wide sheets and superposed in
3% to about 50% of the composite tow or web. It is to
two layers to form sheet A’. Twenty-four ends of the
be understood, however, that as little as about 1% of the 40 spandex tow are disposed over the same width to form
total weight may be provided by the elastic ?laments.
sheet E. The tension on the spandex tow E is so regulated
The following examples, in which parts and percentages
that the spandex ?laments are under a stretch of 5% to
are by weight unless otherwise indicated, further illustrate
10% as they are sandwiched between the layers of inelastic
the present invention. In the examples, the term “elon
tow and enter between input rolls 38 and 40 which are,
gation” when applied to yarns refers to the total yarn
in this case, the input rolls of a Paci?c Converter de
stretch attributable to the elastic ?ber component and is
scribed in U.S. 2,438,469.
the ratio of the extended length of the yarn to its original
length expressed as percent of the original length. The
(0) Preparation of Staple Fiber
Staple ?ber samples are cut from the composite tow
on the Paci?c Converter to lengths of 3", 4%", and 6".
at selected points based on the extended length speci?ed. 50 No ?nish is applied to the composite tow during process
ing. Staple length measurements are made on both the
EYAMPLE I
spandex and inelastic ?bers after cutting and the stand
,(a) Preparation 0]‘ Elastic Filaments
ard deviation (3) and coe?icient of variation (CV) are
calculated according to conventional statistical procedure.
Into ‘a reverse centrifugal mixer maintained at 50° C.
The results are set forth in Table 1, which follows.
are fed a stream of polytetrarnethylene ether glycol at a
term “power” is a measure of the resistance to stretch of
the yarn expressed in grams per denier and is measured
rate of 8 pounds per hour and a stream of liquid p,p’-meth
ylenediphenyl diisocyanate at 2 pounds per hour. The
polytetramethylene ether glycol has a molecular weight of
about 2,000 and is thoroughly pre-dried by treatment with 60
a molecular sieve. The reagents are intimately mixed,
and are discharged continuously into a jacketed pipeline
maintained at about 96° C. and extending for 25 feet.
The pipeline serves as a reactor in which the polyether
glycol is “capped” wit-h 2 mols of the diisocyanate to yield
an isocyanate-terminated polyether. The average time
spent in the pipeline reactor is between 90 and 100 min
utes. On emerging from the pipeline reactor, the iso
cyan'ate-terminated polyether is cooled at once to below
45° C. The cooled isocyanate-terminated polyether is
conducted at a rate of, 9.2 pounds per hour into a high
shear mixer containing a rotating disc, and a stream of
N,N-dimethylformarnide is added at 42.8 pounds per hour.
The mixture (17.7% solids) is thoroughly agitated for 4
minutes and then passes to a chamber in which a mixture
TABLE 1
Nominal cut length,
inches
Inelastic ?ber
Avg.
2. 93
4. 56
5. 81
0
.36
.57
.45
S
CV,
percent
16.1
12. 2
7. 7
v '
pan d ex (elasm)
?ber
Avg.
2.99
4. 50
5. 98
a-
.270
.335
.418
C",
percent
8.8
8.6
7.1
Surprisingly, as seen from Table 1, the cut length of
the spandex ?ber is very close to the desired nominal
length for which the Paci?c Converter was set, and the
length distribution is unusually uniform. It is particular
ly surprising that the spandex ?ber shows a greater accu
racy of average cut length and a more uniform distribu
tion of cut lengths than does the inelastic ?ber.
‘Cutting performance and subsequent processability to
sliver on the Paci?c Converter are observed to be excels
0,077,000
55
lent, free of roll wrapping and tangling. The sliver ob
tained is then spun into yarn using conventional equip
ment and procedures for pin drafting, roving, and spinning.
Samples of each of the three ?ber cut lengths are spun to
238% and the power is .073, .12 and .233 gram per denier
at 60, 75 and 90% of the extended yarn length, respec
tively. Processability and yarn properties are not a?ected
adversely by the use of the low ?lament denier for the
20/1 cc. yarn with a twist of 13.4 2.
inelastic ?ber.
The power and 5
elongation values of the yarn, as previously de?ned, are
1"
'
e
'
f l
Set form m Tabla 2’ Whlch ro‘lows‘
TABLE 2
EXAMPLE lV
.
.
Four ends of the inelastic tow of Example I and 35
ends of the spandex tow of Example I are combined by
the process of Example I and FlGURE l to form a com
POWQY wrung/0611ier
at indicated percent
Yarn
Spandex ?bers nominal cut length,
of extended yarn elqngan ‘168
lengm
10 posits tow having a composition of 90% inelastic ?ber
1 1
0,
__
‘
i
v
.
_.
_
film 40/0 Slg??d?li ?lJBI'. 0116 part Of this Composite tow
i101‘:
is processed on the Paci?c Converter with a 31/2” variable
percent
60%
75%
.
,.
.001
.
99%
.
.100
.10
_
.
.,~
,,
table 4 below show that the ?ber length of the spandex
251
?berris surprisingly close to the nominal cut lnegth in
each instance and the yarn property data in Table 4 again
20 illustrate the desirable level of yarn properties attainable
_
1
,
throueh the use of the
The spandex tow and the inelastic t w or Example I are
L
m
used to prepare a group of composite tows of different
?ber blend ratios, generally following the procedure indi-
recess of this invention.
P \
T
T’*B“E 4‘
.T
cated schematically in the FlGURE of the drawing. The
.
.
.
.a
Yb 1
.
When more
4-
”
_ h
.
34 ‘an
.
wicned between layers of the inelastic tow.
‘
_ b1
.
in all cases, the
ends of spandex tow under 5% to 10% stretch are sand.
1 v
..
to produce the desired blend ratios.
_
*‘Iommal cut'lengm
number of ends 01’ the two tows are varied as necessary 25
.
.
H
EXAppLE H
.
.
cut and the remainder is processed Wlth a 6 straight out.
_ Each portion is then further processed as in Example I
1” to a 20/1 cc. yarn with 13.4 t.p.i. Z twist. The data in
e 6 “mg ‘7
t1
a
.
1 “?m‘i’git?éfgvmge, inches _________________ __
27
52
than one end of inelastic tow is used as either A or A’ in
¢(r;._\_/_.-__.‘-.‘-.t........... _-
;_ 1:8;
.1851;
the FIGURE, they are disposed as superimposed, wide 30
Smh§2¥§§$ég1gg5gggg1
‘I35
63
sueets as in Example 1. Each composite tow sample is
'é»,\-,--;5;Eé;l-t----------- --
‘i675;
fig
processed on the Paci?c Converter to a 41/2” variable cut,
Yam pf-o‘gemgs}""""""""""""""""" "
and subsequentlv processed as in Example I to a 20/1
cc. yarn with 13.4 t.p.1. Z twist. F1001 length distribution
POWQPiHgFamS/denler mindicsledpercenl
60%"
_
_ .
,,'
.
.
.,
_
F
.
L
.
.
in the
1 Paci?c
.
Converter
L
. ,_.sliver is determined for each
‘
of extended yarn1engtl1—
35
-/ _
sample and is reported in lable 3.
nisngahon, percent _____________________ __
'
.074
072
.
. 0
202
274
it will be noted that the cut length distribution of the
spandex ?bers is surprisingly good and again superior to
EXAMPLE V
that of the inelastic ?bers although not so markedly
superior as we'e the straight out samples of Example I ‘10
Th?ty-?ve ends of the spa?deX low of Example 1 are
shown in Table 1. It will further be noticed that this
combmcd with four ends of a commercially available
excellent cutting performance is achieved over the entire
polyethylene terephthalate tow having a total tow denier
range of blend levels represented in these samples. Data
of 450,000 and an individual ?lament denier of 2.25.
on the power and elongation of the yarns spun from the A, The composite tow formed by the process of Example I '
several composite tows are also given in Table 3.
has a ?ber composition of 90% polyethylene terephthalate
TABLE 3
_
_ .
Cut length, inches
Power in grams]
Ccrnpositetow, denler 111
Spandex
Sample
m1
ons
_
content,
percent
Inelastic ?ber
Total
Spandex Inelastic
Aver-
0'
age
Spandex ?ber
CV,
Aver-
percent
age
0'
CV,
as
1. 401
.054
1.410 ______________________________________ _.
2.000
2.100
1.710
2.230
2.300
1.010
1. 010
2.010
.210
.300
.300
.400
.500
.400
.500
.000
1. 820
1.800
1.410
1.000
1.000
1.410
1. 410
1.410
.30
.33
.30
.27
.23
.20
.37
.20
s. 73
7.47
3.70
5.05
5.03
0.50
s. 70
0. 02
4.07
3.72
4. 09
3. 70
4.44
4.47
4.00
4.13
Yarn
percent ofex-
elonga
tended yarnlength
tiou,
percent
60%
75%
90%
007
.141
.311
124
.073
.007
.000
.005
.003
.004
.002
.050
.122
.100
.102
.104
.000
.101
.000
.002
.240
.200
.100
.193
.173
.100
.175
.101
272
204
277
201
273
283
274
207
per
cent
10.0
13.0
17.0
17.0
21.0
22.0
20.2
30.0
4.51
4.35
4. 47
4.59
4. 48
4.47
4.30
4. 27
denier at indicated
.27
.10
.31
.23
.10
.22
.10
.13
0.03
4.30
7.03
0.00
4.00
5.01
4.02
4. 33
EXAMFLE III
fiber and 10% spandex ?ber. The spandex ?bers under
In this example, the inelastic tow of Example I is re- 05 5.40% stretch are sandwiched between layers or" the
polyethylene terephthalate ?bers. The composite tow is
placed by another inelastic tow of the same composition
processed on the Paci?c Converter with excellent processe
and total tow denier but having an individual ?lament
bility and performance.
denier of 2. Three ends of this tow are combined with
in the same manner as in Example I, thirty-seven ends
35 ends of the spandex tow of Example I by the procedure
outlined in Example I to form a composite tow compris 70 of the spandex tow of Example I are combined with three
ends of the polyethylene terephthalate tow of the present
ing 87% inelastic ?ber and 13% spandex ?ber. The
example. The composite tow, comprising 86% poly
composite tow is processed on the Pacific Converter with
a 41/2" straight cut and is subsequently spun to a 42/2 cc.
ethylene terephthalate ?ber and 14% spandex ?ber, is
yarn with 22.8 t.p.i. Z. twist in the singles and 22.8 t.p.i.
processed on the Paci?c Converter to 3%." variable cut.
S twist in the ply. The elongation of the ply yarn is 75 Staple length measurements made on ?ber samples taken
3,077,006
7
5
from the Paci?c Converter sliver again show better cut
length uniformity for the spandex ?ber than for the in
Example I to form a composite tow comprising 90%
inelastic ?ber and 10% spandex ?ber. The composite tow
elastic ?ber as indicated in Table 5.
is cut on the Paci?c Converter to 41/2" variable cut. The
TABLE 5
Polyethylene
terephthalate Spandex ?ber
Cut length
?ber
Average, inches _______________________ __
i1
CV, percent _____________________________ _.
3. 5
3. 2
.257
. 149
7.3
4. 7
spandex tow is given varying amounts of stretch as it
is combined with the inelastic tow at the input rolls of
the Paci?c Converter, as shown in Table 8. From the
staple length data obtained on ?ber samples ‘from the
Paci?c Converter slivers, it will be noted that the prin
cipal effect of increasing the stretch is to decrease the
staple length of the spandex ?bers.
TABLE 8
EXAMPLE VI
Six ends of the spandex tow of Example I are passed
to a pair of driven rolls and thence to a second pair of
Spandex ?ber length
Percent stretch
rolls driven at a linear surface speed 3.3 times that of the
?rst pair of rolls so that the spandex tow is stretched 3.3
times in passing between the two sets of rolls.
_—
Avg,
a
inches
The
4. 5
4. 3
3. 9
3. 7
3. 5
3. l
stretched tow is then wound on a spool motor-driven at
a speed such that the tow is wound in a relaxed condition.
Thirty-eight ends of this previously stretched and relaxed
CV,
Percent
. 614
. 533
. 939
. 868
. 689
. 533
13.6
12. 4
24. l
23. 5
19. 7
17. 2
tow are restretched to 5-10% stretch and then combined
under this stretch with 3 ends of the inelastic tow of Ex
ample III by the procedure of Example I to form a com
It will be apparent to those skilled in the art that any
posite tow comprising 86% inelastic ?ber and 14% span 25 of a great number of elastic and inelastic natural and
synthetic ?bers, as well as ?ber blends, may be substi
dex ?ber. The composite tow is processed on the Paci?c
tuted for those speci?cally disclosed in the foregoing
Converter with a 41/2" variable cut. The Paci?c Con
examples. Among the many inelastic ?bers are those
verter’s sliver is given 6 passes of pin drafting. Another
prepared from the synthetic ?ber-forming materials such
composite tow is prepared and processed in an identical
manner except that the spandex ?ber is not stretched and
relaxed before incorporation under 5-l0% stretch in the
composite tow. Sliver from the ?nal pin drafting opera
tion for each sample is examined for neps and unsepa
rated clumps of ?bers. The results shown in Table 6
clearly show the improvement obtained by the stretching
and relaxing pre-treatment of the spandex tow.
as polyesters, e.g., polyethylene terephthalate; polyamides,
e.g., polyhexamethylene adipamide, polyhexamethylene
sebacamide, polycaproamide, and copolymers of various
amides; acrylic polymers and copolymers, e.g., polyac
rylonitrile, copolymers of acrylonitrile with vinyl chloride,
vinylidene cyanide, vinyl pyridine, methyl acrylate; vinyl
polymers, e.g., vinyl chloride/vinyl acetate copolymers;
polymers and copolymers of tetra?uoroethylene, mono
TABLE 6
chlorotri?uoroethylene, and hexa?uoropropylene; poly
Neps/250
grains
Unsepartaed ?bers 40 ethylene; cellulose derivatives, e.g., cellulose acetate, re
generated cellulose, ethyl cellulose, cellulose triacetate;
(clumps) per 250
grains sliver
sliver
Small
Without stretching and relaxing ______ __
With stretching and relaxing _________ __
100
60
Large
25
8
2
0
glass, or from any natural ?bers, such as cotton, wool,
silk, jute, linen, or a blend of two or more inelastic ?bers.
A particularly suitable class of elastic ?bers for use in
this invention are the spandex ?bers. Among the seg
45 mented polyurethanes of the spandex type are those de
scribed in several patents, among which are US. Patents
2,929,800, 2,929,801, 2,929,802, 2,929,804, 2,953,839,
EXAMPLE VII
2,957,852, and Re. 24,689. As described in the aforemen
One end of the inelastic tow of Example I is passed
tioned patents, the segmented polyurethane elastomers
through a Turbo Stapler as described in US. 2,748,426. 50 are comprised of amorphous segments derived from poly
At the same time, three ends of the spandex tow of
mers having a melting point below about 50° C. and a
Example I are fed to the Turbo Stapler so that they by
molecular weight above about’ 600, and contain from
pass the heating and drawing zone and are folded into
about 5% to 40% of crystalline segments derived from
the inelastic tow at the rolls commonly known as the
a polymer having a melting point above about 200° C.
intermediate rolls. As they enter the intermediate rolls
in the ?ber-forming molecular weight range. Most of
and are combined with the inelastic tow, the spandex tows
suchpolyurethanes, when in ?lament form, have elonga
are under a stretch of about 50%, and still further stretch
tion greater than 150%, tensile recovery of over 90%, and
is applied as the combined tows pass to the breaker bars.
a stress decay of less than 20% as ‘de?ned in U.S.
Staple length measurements on ?bers taken from the
2,957,852.
Turbo Stapler sliver show more uniform staple lengths
Fibers of other types of condensation elastomers are
for the spandex ?ber than for the inelastic ?ber, as shown
also suitable. US. 2,670,267 describes N-alkyl-substi
in Table 7.
~
tuted copolyamides which are highly elastic and have a
TABLE 7
suitable low modulus. A copolyamide of this type, ob
tained by reacting adipic acid with a mixture of hex
Fiber length
Inelastic
?ber
Average, inches ............................. ._
Spandex
er
6. 8
8. 0
0-.
1.05
. 757
CV, percent _________________________________ -_
15. 4
9. 46
EXAMPLE VIII
Three ends of the inelastic tow of Example I and ‘four
ends of spandex t-ow identical to that of Example I ex
cept having a total denier of 40,000 are combined as in
05 amethylenediamine,
N - isobutylhexamethylenediamine,
and N,N'-isobutylhexamethylenediamine, produces an
elastomer which is particularly satisfactory for the pur
poses of this invention. US. 2,623,033 describes linear
70 elastic copolyesters prepared by reacting glycols with a
mixture of aromatic and acyclic dicarboxylic acids. Co
polymers prepared from ethylene glycol, terephthalic acid,
and sebacic acid have been found to be particularly use—
ful. Another class of useful condensation elastomers is
described in US. 2,430,860. The elastic polyamides of
3,077,006
3
10
this patent are produced by reacting polycarbonamides
with formaldehyde.
This last form shows good ai?nity for spandex ?bers but
Elastic ?bers of textile denier from ?ber-forming addia
tion polymers such as, for example, copolymer of buta
diene/styrene, butadiene/acrylonitrile and butadiene/Z
vinyl pyridine, polychlorobutadiene, copolymers of iso~
butylene with small proportions of butadiene, chlorosul
fonated polyethylene, copolymers of monochlorotri?uoro
ethylene with vinylidene fluoride, and the like, may be
no af?nity for cotton.
It has now been found that one-bath unions of cotton
and spandex ?bers can be obtained by adjusting the
alkalinity of the vat dye bath to a point where there is
equilibrium between the sodium salt (basic leuco form)
and the half acid. In this one-bath method, the vat dye
is reduced in the usual manner with sodium hydrosul?te,
but with only about half the usual amount. of alkali in
employed.
10 the bath. The exact amount of alkali to be used will
Both the elastic and inelastic ?laments may be supplied
vary somewhat with the vat dye being used, and can be
on packages of any convenient and available form. They
readily determined by those skilled in this art. The
alkalinity of vat dye baths for cotton is commonly equival~
may be in the form of individual ?laments, or of relatively
small bundles of ?laments of low total denier, e.g., 200
cut to about 8 g. NaOH/liter. Optimum alkalinities for
to 1,000, or as tows or" high total denier of the order of 15 union dyeing of cotton/ spandex blends with several repre
400,000. While the rawing shows a three-layered com
sentative dyes are shown in the following table. Identi
?cation of the dyes is according to the Technical Manual
posite tow structure, it is to be understood that other
structures are within the scope of the invention provided
of the American Association of Textile Chemists and
that the elastic ?bers are sandwiched between at least
Colorists, 1960 edition, page 308. The C1. references
two layers of inelastic ?bers. The choice of alternate ar 20 are to the Colour Index, second edition, 1956.
rangements will depend on the equipment to be used and
TABLE 9
the form in which the starting yarns is supplied.
The slivers made by the process of this invention can
Optimum
be used in the manufacture of yarns suitable for use in
elastic or stretchy woven, knitted, and non-woven fabrics
for use in universal ?tting apparel (socks, polo shirts,
underwear, bathing suits, gloves, elastic cuffs, sweaters,
waistbands, suits, coats, dresses, skirts, action sportswear,
leotard-type outer wear, and ac essories such as tapes,
webbings, and other woven, non-woven, or knit apparel
fabrics), household products (form-?tting upholstery,
slipcovers, sheets, carpets, mattress coverings, and narrow
tapes and webbings for a Wide variety of uses), industrial
products (transportation upholstery, woven and non
woven felts, tapes and Webbings for varied applications),
and medical products (surgical bandages, supports, elastic
dressings, surgical stockings, and splint tapes). in addi
Dyes for unions
0.1T.
alkalinity
for unions—
g. NaOH/liter
“Ponsol” .Tade Green __________ __ Vat Green 1, 59825.."
4. 0
“Ponsol” Golden Orange 2BG__
“Ponsol” Navy Blue llG_______
3. 5
3. 5
“Ponsol” Brilliant Red B _____ __
3. 5
At the optimum alkalinities of Table 9, the shades
produced on the cotton and on the spandex ?ber are
equivalent, that is, good unions are achieved. When the
desired shade has been obtained, the leuco forms are
then oxidized according to conventional practice for vat
dyes, e.g., with sodium perborate. Union dyeing of
cotton/spandex blends made by this modi?ed one-bath
tion, low stretch, high recovery fabrics can be made suit
procedure with the vat dyes listed in Table 9 and similar
able for use in outer apparel (sweaters, knit jersey, and
woven, knit, or non-woven suitings and dress goods), 40 dyes exhibit lightfastness in excess of 40 hours and good
washfastness.
household items (rugs, carpets and upholstery), and in
The process of this invention makes possible the produc
dustrial products (Woven, non-woven, and knit compres
tion of new and useful elastic yarns making more efficient
sion or impact-bearing structures). Illustrations of vari
use of the elastic ?ber content than is obtained by the con
ous speci?c products which may be prepared from the
ventional cut staple ?ber route. The use of the composite
?ber blends and yarns made by the process of this inven
tow eliminates the limitations on denier and length result~
tion are shoe laces, shoe liner fabric, shoe upper fabrics,
ing from formation of neps and high ?ber breakage during
house slippers, skin diving suits, snow suits, ski pants,
carding. The use of longer staple ?ber lengths for the
football pants, slacks, llannels, sport shirts, bulky knit
elastic ?ber content reduces the number of free ?ber
sweaters, blankets, swimming pool covers, toupee bases,
ends
in the yarn bundle and is advantageous in improving
belts, suspenders, garters, watch bands, ropes, elastic sew
such yarn and fabric performancy characteristics as
ing thread, shock cords, bookcover jackets, bookbinding
cloth, synthetic paper, elastomer-coated fabrics, and
super-dense felts, such as papermakers’ felts.
The ?ber blends, yarns, fabrics, and other textile pro
ducts prepared from the slivers made by this invention
may be given the customary ?nishing treatments where
necessary or desired, such as scouring, Washing, drying,
pressing, dyeing, heat-treating, and softening.
With particular reference to dyeing, good union dyeings
fuzzing, pilling, hand, color change, and dyeability. As
illustrated in the examples, the use of longer ?ber lengths
results in more e?lcient use of the elastic ?ber component
as re?ected in the values for yarn power. Improved
recovery of yarns and fabrics is a direct consequence
because of the increased power available to overcome
friction caused by fabric or yarn geometry. it is particu
larly surprising and unexpected that a ?ber of elastic
of excellent lightfastness can be achieved on blends of 60 characteristics can be cut to uniform ?ber length when
incorporated under tension in a composite tow.
spandex ?bers with cotton in a one-bath procedure. Vat
As many Widely di?erent embodiments of this inven
dyes of the anthraquinone type are used under essentially
tion may be made Without departing from the spirit and
conventional vat dyeing conditions except that the alkalin~
scope thereof, it is to be understood that this invention is
ity of the dye bath is reduced.
not to be limited to the speci?c embodiments thereof ex
65
It is Well known to convert vat dyes by strong reducing
cept as de?ned in the appended claims.
agents, such as sodium hydrosul?te, to the sodium salt
I claim:
or basic leuco forms under conditions of relatively high
1. In the method of producing a blend of separate
alkalinity, e.g., 8 g. NaOl-l/liter. Excellent fastness
out lengths of elastic and inelastic ?bers the steps com
properties result When cotton is dyed under these condi 70 prising forming a plurality of separated flat sheets of in
tions. The spandex ?bers show very low a?lnity for the
elastic ?laments and continuous elastic ?laments, ten~
basic leuco form of vat dyes. Under appropriate and well
sioning said sheets of elastic ?laments to stretch said ?la~
known conditions, the dyes can be converted two further
ments a predetermined amount beyond their normal re
steps, ?rst to the half sodium salt or half acid form, and
laxed length, combining said sheets of elastic and in
second to the dihydroxy derivative or acid leuco form. 75 elastic ?laments in layered relationship to form a com
3,077,0oe
ll
amount beyond their normal relaxed length, combining
posite web wherein said tensioned elastic ?laments lie be
tween adjacent sheets of said inelastic ?laments, and
thereafter feeding said composite web to fracturing means
whereby said ?laments are cut to staple lengths.
2. The method of claim 1 wherein said elastic ?la 5
?laments, and thereafter feeding said composite web to
ments are stretched an amount from about 5% to about
fracturing means whereby said ?laments are cut to staple
said sheets of elastic and inelastic ?laments in layered
relationship to form a composite web wherein said ten
sioned elastic ?laments lie between said sheets of inelastic
15% greater than their relaxed length.
lengths.
3. The method of claim 2 wherein said composite web
6. The method of claim 5 wherein said elastic ?la
is comprised of from. about 3% to about 50% by Weight
ments are extended an amount from about 5% to about
of said elastic ?laments.
10 15% greater than their relaxed length.
4. The method of claim 2 wherein said elastic ?la
7. The method of claim 6 wherein said composite web
ments are subjected to at least one cycle of stretching to
is comprised of from about 3% to about 50% by weight
from about two to ?ve times their original length and
of said elastic ?laments.
relaxing after being formed into a flat sheet.
8. The method of claim 6 wherein said elastic ?la
5. In a method of converting continuous elastic ?la 15
ments and inelastic ?laments into ‘a sliver of intermingled
ments are subjected to at least one cycle of stretching to
staple ?bers, the preliminary steps comprising forming a
from about two to ?ve times their original length and
relaxing after being formed into a flat sheet.
plurality of separated ?at sheets of continuous elastic ?la
ments and inelastic ?laments, tensioning said sheets of
elastic ?laments to extend said ?laments a predetermined
No references cited.
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