Note: Descriptions are shown in the official language in which they were submitted.
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TITLE
COSPUN 2GT/6,6 CONTAINING ANTISTAT
BACKGROUND OF THE INVENTION
l. Field of the Invention
This invention relates to antistatic cospun
yarn comprising poly(hexamethylene adipamide)
filaments and poly(ethylene terephthalate) filaments
and to woven and knitted fabrics made therefrom.
2. DescriPtion of the Prior Art
The desirability of reducing the
electrostatic propensity of synthetic fibers in
textile applications is well known. A recent
approach to the solution of this problem has been the
incorporation of an N-alkyl substituted
polycarbonamide into the filaments as described by
Alderson U.S. Patent 3,900,676. This patent suggests
that such antistatic filaments may form one component
of a cospun yarn. It is an object of this invention
to provide a cospun yarn containing only a minor
proportion of the modified filaments w~ich is capable
of achieving the high level of antistatic protection,
as shown by reduced garment cling, that is afforded
by yarn composed entirely of the modified filaments.
SUMMARY OF_THE INVENTION
This invention provides an antistatic cospun
yarn comprising a major amount up to about 70 weight
percent of poly(ethylene terephthalate) filaments
with the remainder being poly(hexamethylene
adipamide) filaments containing 3 to 10 weight
percent of an N-alkyl substituted polycarbonamide,
the filaments having a denier of from l to 10.
Knitted and woven fabrics of such yarn are also part
of this invention.
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DETAILED DESCRIPTION_OF THE INVENTION
The cospun yarn of the invention may be
prepared in accordance with the general techniques
described in Reese U.S. Patent 3,681,910. Basically,
the two fiber-forming polymeric compositions are
separately fed to one or more spinning assemblies and
extruded to form groups of discrete filaments from
each of the polymer compositions in the desired
proportions. The filaments are then combined into a
single composite yarn and drawn as an integral yarn.
The filaments of the yarn are of textile denier~
preferably from 1 to 10 denier per filament (dpf).
The two fiber-forming polymeric compositions
employed in the present invention are poly~ethylene
terephthalate) hereinafter 2GT and poly(hexamethylene
adipamide) hereinafter nylon 6,6. The nylon 6,6 to
be extruded contains from 3 to 10 weight percent of
an N-alkyl substituted polycarbonamide as an antis~at
modifier. The latter, which is described in more
detail below is known to reduce the static propensity
of synthetic yarn. The desired yarn desirably
contains a major amount of 2GT filaments, preferably
about 60% by weight, but no more than 70% by weight.
The remaining filaments in the yarn are constituted
~ 25 by the modified nylon 6~6 filaments. Surprisingly it
; has been found that the static propensity of fabrics
of such yarns as shown by cling tests is no greater
than that of similar fabrics composed entirely of the
modified nylon 6,6 filaments.
The nylon 6,6 filaments contain from about 3
to 10 weight percent of an N-alkyl substituted
polycarbonamide modifier in which the tertiary
carbonamide groups are an integral part of the
polymer molecule. Useful modifiers are those
35 disclosed in Alderson U.S. 3,900,676. The modifier
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has a molecular weight of at least about 800 to 5000
and is dispersed throughout the filament
substantially as a separate phase in the form of
discrete elongated conductive particles aligned
essentially parallel to the filament axis, all as
described in the aforementioned Alderson patent. The
elongated conductive particles should have a ratio of
their length, L, to average diameter, D, of at least
about 100 as taught in said Alderson patent.
In preparing the products of the present
invention, the N-alkyl polycarbonamide may be mixed
directly with the fiber-forming nylon 6,6 and then
immediately spun into filaments. If desired, it may
be combined with polymer flake and then spun into
filaments. Less reactive N-alkyl polycarbonamides
can be introduced into the autoclave during
production of the fiber-forming polycarbonamide.
Preferably, the N-alkyl polycarbonamide and
fiber~forming nylon 6,6 are mixed in molten condition
and immediately spun into filaments.
Useful N-alkyl polycarbonamides are
disclosed particularly in column 3 line 7 through
line 21 of column 4 of U.S. Patent 3,900,676. In the
examples which follow, the modifier employed is the
reaction product of a mixture of 80~ N,N'-di-n-butyl
hexamethylene diamine and 20% of mono-N-butyl
~ hexamethylene diamine and dodecanedioic acid.
; Stearic acid is employed as a viscosity stabilizer.
The modifier had a melting point less than 0C, a
calculated molecular weight o about 2100 and a
viscosity of 1100 centistokes at 95C.
The cospun yarns of the examples which
follow were prepared using the general procedures
described in the aforementioned Reese patent. One
filament group of the mixed filament yarn was 2GT
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filaments while the other was nylon 6,6 filaments,
the latter having incorporated therein the antistat
modifier mentioned above. Two techniques for
incorporation of the N-allcyl substituted
polycarbonamide are illustrated. In Example I, the
modifier was injected into the nylon 6,6 stream
shortly beore ex~rusion by injection of the modifier
into the screw melter-extruder and mixing before the
melt-spinning operation. In Example II, the modifier
was combined with the nylon 6,6 in ~he autoclave in
the polymerization cycle.
In the examples which follow, cospinning is
achieved by separately meter ing 2GT and nylon 6,6
containing modifier to two separate inlet ports of a
melt spinning assembly designed to accommodate the
two streams and keep them separate. The polymers are
discharged in a conventional manner through a
spinneret. The two groups of filaments merge and are
then drawn and wound up in a package. Details are
given in the examples~
TEST PROCEDURES
Relative_viscosity, RV, of 2G~ as used in
the following examples is the ratio of the viscosity
of a 4.75 weight percent solution of 2GT in
hexafluoroisopropanol to the viscosity of the
hexafluoroisopropanol per se, measured in the same
units at 25C. The RV of nylon 6,6 is measured as
described in U.S. 3,681,910 at column 3, lines 25-30.
Sail Test - this test is performed as
described in U.S. 3,900,676 at column 16, lines 11-36.
Keithley Log R - this test is performed as
described in AAATC 76-1978 p. 233.
Skein_Loq R - this test is similar to the
yarn log R test in U.S. 3,900,676 except that for
Skein Log R, sufficient revolutions were wound to
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make a skein with a cross-section of 720,000 denier.
The skein i5 scoured, drled and conditioned at 20~
relative humidity ~or 24 hours. The skein is cut and
clamped without spreading between electrodes 2.0
inches apart so that 360,000 denier is between the
electrodes. The resistance is measured at 20~
relative humidity with a megohmeter under a potential
of 210 volts.
EXAMPLE I
Cospun yarns of trilobal 2GT filaments ~60
by weightj and trilobal nylon 6,6 filaments (40~ by
weight) containing antistat modifier were prepared
from nylon 6,6 (42 R.V. with 0.02% TiO2) containing
4.6% by weight of modifier and from 2GT (22 R.V. with
0.1~ TiO2). The polymers were melt spun at 291C
through a single spinneret into a yarn (6 filaments
of each polymer) in which the nylon 6,6 filaments had
an R.V. o~ 47.7 and the 2GT filaments an R.V~ of
21.5. The extruded filaments were air-quenched.
Finish was applied and the filament streams were
conver~ed to a feed roll operating at 1564 ypm
surface speed and then passed through a steam jet at
200C to a draw roll operating at a surface speed of
3674 ypm for a draw ratio of 2.35. The drawn yarn
was annealed at 138C in a hot chest kesidence time
about 0O2 sec.). The drawn yarn was passed through
an interlace jet at 55 psig air, treated with a
second finish and wound up at 3681 ypm at a tension
of 7 grams. The yarn denier was 40, percent
elongation was 35.4, tenacity was 3.5 gpd. The nylon
6,6 filaments had a denier of 2.7 while the 2GT
filaments had a denier of 4Ø The antistatic
performance of skeins and warp knit fabrics from the
yarns is reported as Item 1 on Table I below.
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EXAMPLE II
A process similar to that used in Example I
was performed except that the polymers used were
nylon 6,6 ~32 R.V. wi~h 0.02~ TiO2) containing
5.25% by weight of modiEier and 2GT (22 R~V. with
0.1~ TiO2). The resulting yarn was made up of
nylon 6,6 filaments (40~ by weight) of 39.5 R.V. and
2GT filaments (60% by weight) of 21.2 R.V. The yarn
denier was 40, percent elonga~ion was 42.5, and
tenacity was 3.5 gpd. The antistatic performance of
the yarn and the performance of warp knit fabrics of
such yarns is reported on Table I as Item 2.
Item 3 of Table I represents a cospun
trilobal control yarn containing no antistat
modifier, but is otherwise similar to Items 1 and 2.
Items 4, 5 and 6 are commercial warp knit
fabrics from 40 denier yarn. Item 4 is a trilobal
nylon antistatic 13-filament yarn. Item 5 is a
quadralobal nylon antistatic 20-filament yarn and
20 Item 6 is a round nylon 13-filament yarn containing
no antistat. Items ~ and 5 contain the same modifier
as used for Item 1 and at a concentration of 5.25%.
Item 7 and 8 represent experiments performed to
compare results obtained from nylon 6,6 yarns in
which modifier 5.25% concentration was added to 100%
of the filaments (Item 7~ and nylon 6,6 yarns in
which modifier was added at 5.25~ concentration to
only 50% of the filaments (Item 8). In each case the
same modifier was used.
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_A LE I
SAIL TEST
PRIMARY
DECLING ANTISTATIC PERFORMANCE
SKEIN MINS. KEITHLEY LOG "_"
5 ITEM LOG R 5 "C" WASH AS REC'D. _ C" WAS~
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12~8 3~8 14~7 14~4
2 12~9 3~7 1~L~6 14~6
3 ;~14~0* 9~2 17~4 17~0
4 12~9 ~~ 1~Lo6 14~4
10 5 12~5 5~2 13~0 13~7
6 ~14~0* ~~ 17~1 17~4
7 12 ~ 95
8 13~25
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* The value reported was the upper limit of the
instrument capability.
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