Note: Descriptions are shown in the official language in which they were submitted.
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PROCESS OF MAKING A FIRE RESISTANT THREAD
Field of the Invention
The present invention relates to a process for producing a fire resistant
thread.
Background of the Invention
It has long been a problem in the textile industry to create an inexpensive,
sewable fire resistant thread. The sewing thread should allow easy movement
when
tension is applied and ease in needle threading; should resist friction during
sewing;
should have sufficient elasticity to avoid the breaking of stitches; and
should have
sufficient strength to hold seams during laundering or dry cleaning and in
use. Threads
for special uses may require appropriate treatment. Garments made of fire-
resistant
fabrics, for example, may be sewn with thread that has also been made fire-
resistant.
Such a thread would have a variety of uses including, but not limited to:
sewing
mattress parts together, sewing fire fighting gear and clothing together, and
sewing
upholstery together. Additional uses for such a sewable thread include, but
are not
limited to, seat belts, air bags, cargo nets, cargo straps, and carpeting. A
sewable fire
resistant thread must meet the federal requirements of 16 CFR 1632 and Cal 129
in
order to be used to sew the various components of a mattress together.
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A variety of methods and steps have been used in order to fabricate a fire
resistant thread. The various factors which must be taken into account when
developing a thread are numerous. There are a wide variety of both synthetic
and
natural yarns to choose from. Among the yarns, there are a wide range of
thicknesses
and finishes to choose from. One must then determine the proper and optimum
number
of yarns to combine in order to form a thread as well as determining the
proper and
optimum number of twists and the direction of those twists required to obtain
a thread
having the physical and functional characteristics both required and desired.
Hence, there exists an unsatisfied need for a method of making a fire
resistant
thread.
Summary of The Invention
A method for producing a fire resistant thread comprising the steps of:
unwinding
a first yarn being a fire resistant polymer from a first spool onto a first
pirn; unwinding a
second yarn being a synthetic and/or natural yarn from a second spool onto a
second
pirn; unwinding a third yarn being a synthetic and/or natural yarn from a
third spool onto
a third pirn; unwinding the first yarn, the second yarn and the third yarn
from the first
pirn, the second pirn and the third pirn; twisting the first yarn, the second
yarn and the
third yarn each in a first direction; twisting the first yarn, the second yarn
and the third
yarn together in a second direction to form a three-ply thread; coating the
three-ply
thread with a bonding agent in order to form the fire resistant thread; and
collecting the
fire resistant thread.
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Brief Description of the Drawings
For the purpose of illustrating the invention, there is shown in the figures a
form
that is presently preferred; it being understood, however, that this invention
is not limited
to the precise arrangements and instrumentalities shown.
Figure 1 illustrates an embodiment of a method for producing a fire resistant
thread.
Figure 2 illustrates an embodiment of a fire resistant thread.
Figure 3 illustrates an embodiment of a method for producing a fire resistant
thread.
Detailed Description of The Invention
Referring to the drawings, wherein like numerals indicate like elements, there
is
shown in Figure 1 an embodiment of a method for producing a fire resistant
thread 10.
In this embodiment, the present invention may be summarized in five major
steps: The
first step includes pirn winding 1 which involves the unwinding of each yarn
20 from a
spool followed by winding each yarn 20 on a pirn. The second step includes a
first
twisting process 2 during which each yarn 20 is tensioned and then given a
twist in a
first direction. The third step includes a second twisting process 3 during
which each of
the yarns are combined together, the yarns are tensioned and then given a
twist in a
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second direction. The forth step includes a coating process 4 during which the
combined yarns are coated with a bonding agent resulting in a fire resistant
thread 10.
The fifth step includes a spooling process 5 during which the fire resistant
thread 10 is
collected and spooled. In one embodiment of the present invention, the five
steps
described above may be accomplished on five separate machines. In another
embodiment of the present invention, the five steps described above may be
accomplished on one or more machines.
Pirn winding 1, as used herein, is the process of taking a larger supply
package
of raw material and making it into smaller packages that will run
approximately the same
duration. In one embodiment of the present invention, the pirn is run with a
bi-conical
taper with a sharper edge (shoulder). In another embodiment of the present
invention,
the taper on the pirn is a cocoon shape with a more dull edge (shoulder). In
another
embodiment of the present invention, the smoother shoulder, the normally
coarse para-
aramid fiber would make a more evenly distributed delivery to the first
twisting process
and allow for the yarn to run completely without breaking or tangling. In one
embodiment of the present invention, the pirn winding may take place using a
machine
made by LEMA LEZZENI (Cossato, Italy) such as machine type CLV/C 200 or a
similar
machine.
First twist process 2 twists the input (pirns) yarns in a first direction with
a certain
amount of turns per inch (t.p.i.) and winds them in a parallel manner
preparing these
yarns for the second twist process 3. In the first twist process 2, each yarn
20 may
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have its own individual tension setting. That is to say that a first yarn 22
is tensioned at
one setting, a second yarn, 24 is tensioned at the same or a different
setting, and a third
yarn, 26 is tensioned at the same or a different setting as the first yarn 22
and/or the
second yarn 24. In one embodiment of the present invention, the first twist
process may
take place using a machine made by Thema Systems S.r.I. (Moglia, Italy), such
as the
DT/140 N Spindle or a similar machine. In one embodiment of the present
invention the
amount of tension on the thread is adjusted as is the percentage of difference
between
the drive spindles and the overfeed roll. This adjustment allows for the
processing of a
high tenacity, low elongation fiber (e.g. a fire resistant polymer) and a mid
tenacity, high
elongation fiber (e.g. a synthetic or natural fiber) to be run together
without bunching or
knotting. This adjustment prevents the creation of loops in the yarns which
would make
it unlikely that the fire resistant thread would function as a sewing thread
without binding
up or breaking in the needle.
Second twist process 3 twists the yarns in a second direction (the opposite
direction of the first direction) with a certain amount of turns per inch
(t.p.i.) to create a
smooth, even multiple-ply thread. In one embodiment of the present invention,
much
like the first twist process 2, the amount of tension is maintained in a
consistent manner
allowing for the full length run of the yarn. Knots or uneven wind at this
point would
prohibit the even application of the coating and make proper stitch formation
impossible.
In one embodiment of the present invention, the second twist process 3 may
take place
using a machine made by Thema Systems S.r.l. (Moglia, Italy), such as the R
325N
DT/100 CE or a similar machine.
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The coating process 4 coats the combined yarns with a bonding agent resulting
in a fire resistant thread 10. Looking to Figure 3, in one embodiment of the
present
invention, the coating process 4 is accomplished by running the thread from a
supply
creel 200, through a first set of stretch rollers 210, a dipping tank 220, a
squeegee 230,
a first oven 240, a second oven 250, a third oven 260, a second set of stretch
rollers
270, over a lick roll lubrication applicator 280 and on to a final spool 290.
In one
embodiment of the present invention the coating process 4 is accomplished on
an M&P
coating range. In another embodiment the coating process 4 is modified to
allow for the
even stretching of the fire resistant thread 10 without any damage to the
individual
fibers. At the same time the process preserves the smoothness required to make
the
fire resistant thread sewable. Without these tensioning adjustments to the
coating
range, knots would result that would make the fire resistant thread unusable
in any
needle application. In one embodiment of the present invention the coating
process
may be carried out on a TAF 52 Bonding machine manufactured by MP s.r.l.
(Urgnano,
Italy) or a similar machine.
The spooling process 5 is the fifth step during which the fire resistant
thread 10 is
collected and spooled. Spooling is the act of placing the fire resistant
thread 10 on a
serving package designated by the customer. In one embodiment of the present
invention, a final level of lubrication is applied to the fire resistant
thread for optimum
performance. In another embodiment of the present invention the coating
process may
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be carried out on a spooling machine manufactured by Texilmesa s.r.l. (Lecco,
Italy) or
a similar machine.
Referring again to the drawings, wherein like numerals indicate like elements,
there is shown in Figure 2 an embodiment of a fire resistant thread 10. The
present
invention provides a fire resistant thread. The fire resistant thread may be
comprised of
three or more yarns 20 which may be referred to as a first yarn 22, a second
yarn 24
and a third yarn 26. In one embodiment, the first yarn 22 is a filament yarn
comprised
of a fire resistant polymer. The second yarn 24 and the third yarn 26 are each
comprised of a synthetic and/or natural yarn. The first yarn 22, the second
yarn 24 and
the third yarn 26 individually have a first twist in the same direction. The
first 22, second
24 and third yarns 26 are then combined using a second twist which is in the
opposite
direction of the first twist resulting in a 3-ply thread 50. In one
embodiment, the fire
resistant thread is a sewing thread. Sewing thread, as used herein, refers to
a thread
which may be used to sew two or more fabrics together.
The present invention discloses a method for producing a fire resistant thread
10
comprising the steps of: unwinding a first yarn 22 being a fire resistant
polymer from a
first spool 100 onto a first pirn 105; unwinding a second yarn 24 being a
synthetic and/or
natural yarn from a second spool 110 onto a second pirn 115; unwinding a third
yarn 26
being a synthetic and/or natural yarn from a third spool 120 onto a third pirn
125;
unwinding the first yarn 22, the second yarn 24 and the third yarn 26 from the
first pirn
105, the second pirn 115 and the third pirn 125; twisting the first yarn 22,
the second
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yarn 24 and the third yarn 26 each in a first direction; twisting the first
yarn 22, the
second yarn 24 and the third yarn 26 together in a second direction to form a
three-ply
thread 50; coating the three-ply thread with a bonding agent in order to form
the fire
resistant thread; and collecting the fire resistant thread.
Unwinding, as used herein, refers to the process of removing a yarn or thread
from a spool or pirn, preferably without breaking or damaging the yarn or
thread.
Yarn 20, as used herein, refers to a strand comprised of fibers, filaments 30,
or
combinations thereof, natural or synthetic, suitable for use in sewing
threads. In one
embodiment, the yarn may be comprised of a number of fibers twisted together.
In
another embodiment, the yarn 20 may be comprised of a number of filaments 30
grouped together but not twisted. In yet another embodiment, the yarn 20 may
be
comprised of a number of filaments 30 twisted together. In still another
embodiment,
the yarn 20 may be comprised of a single filament 30, called a monofilament,
either with
or without twist. In still another embodiment, the yarn 20 may be comprised of
a
combination of natural and synthetic fibers. In still another embodiment, the
yarn may
be comprised of a combination of natural and synthetic filaments.
Fiber, as used herein, refers to units of matter having length at least 100
times
their diameter or width. Typically textile fibers are units that can be spun
into a yarn by
various methods including twisting. Fibers suitable for textile use possess
adequate
length, fineness, strength, and flexibility for yarn formation and for
withstanding the
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intended use of the completed yarn. Other properties affecting fiber
performance
include, but are not limited to, elasticity, durability, uniformity, luster,
crimp (waviness),
moisture absorption, reaction to heat and sunlight, reaction to the various
chemicals
applied during processing and in the dry cleaning or laundering of the
completed fabric,
and resistance to insects and microorganisms. The wide variation of such
properties
among textile fibers determines their suitability for various uses. In one
embodiment,
fiber may refer to staple. In another embodiment, fiber may refer to
continuous filament
and/or tow.
Filament 30, as used herein, refers to a fiber of an indefinite or extreme
length
such as found naturally in silk. Synthetic strands are extruded into filaments
that are
converted into filament yarn, staple, or tow.
Yarns may be categorized into different types which include single, ply, or
cord.
Single, or one-ply, yarns may refer to single strands composed of fibers and
or filaments
held together by at least a small amount of twist. In one embodiment of the
present
invention, the first, second, third, or additional yarns may be filaments
grouped together
either with or without twist. In yet another embodiment, the first, second,
third, or
additional yarns may be synthetic filaments extruded in sufficient thickness
for use
alone as yarn (monofilaments). In yet another embodiment, the first, second,
third, or
additional yarns may be continuous multifilament yarns. Single yarns of the
spun type,
composed of many short fibers, may be held together with a twist in either S-
twist 40 or
Z-twist direction 35.
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Ply, plied, or folded, yarns may be composed of two or more single yarns
twisted
together. In one embodiment, the fire resistant thread may be a three-ply
thread 50 may
be comprised of three single yarns. In yet another embodiment, the first,
second, third
or additional yarns are each twisted in one direction (e.g., the "S" direction
40) and are
then combined and twisted in the opposite direction (e.g., the "Z" direction
35) to make a
ply thread. In one embodiment, the fire resistant thread 10 may be comprised
of single
yarns 20 twisted in the "S" direction" 40 which are then combined and twisted
in the "Z"
direction 35. In another embodiment, the fire resistant thread 10 may be
comprised of
single yarns 20 twisted in the "Z" direction" 35 which are then combined and
twisted in
the "S" direction 40.
Cord yarns may be produced by twisting ply yarns together, with the final
twist
usually applied in the opposite direction of the ply twist. In one embodiment,
a fire
resistant thread may be a cord yarn having an SZS form, with S-twisted singles
made
into Z-twisted plies that are then combined with an S-twist. In another
embodiment, a
fire resistant thread may be a cord yarn having a ZSZ form. In yet another
embodiment,
a fire resistant thread may be a cord yarn having an SSZ or a ZZS pattern.
First yarn 22, as used herein, refers to a yarn, as described above, which is
a
filament yarn. Filament yarn, as used herein, refers to a yarn composed of one
or more
continuous filaments assembled with or without a twist. In one embodiment of
the
present invention, the first yarn 22 may be comprised of filaments 30 having a
first twist
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in either the "S" 40 or "Z" 60 direction, made of a fire resistant polymer. In
another
embodiment, the first yarn 22 may be comprised of fibers having a first twist
in either the
"S" 40 or "Z" 60 direction, made of a fire resistant polymer. In still another
embodiment,
the first yarn 22 may be a monofilament yarn. In still another embodiment, the
first yarn
22 may be a continuous multifilament yarn.
Fire resistant polymer, as used herein, refers to a polymer that does not burn
at
all, burns slowly, or is self-extinguishing after removal of an external
source of ignition.
A yarn 20 may be fire resistant because of the innate properties of the
fiber/filament, the
twist level of the yarn, the presence of flame retardants, or a combination
thereof. In
one embodiment of the present invention, the first yarn 22 may be comprised of
filaments 30 made of a fire resistant polymer including, but not limited to,
an aramid, a
polyester polyarylate, a PBO, a melamine formaldehyde, or combinations
thereof. In
another embodiment of the present invention, the first yarn 22 may be
comprised of
fibers made of a fire resistant polymer including, but not limited to, an
aramid, a
polyester polyarylate, a PBO, a melamine formaldehyde, or combinations
thereof. In
still another embodiment, the first yarn 22 may be an aramid yarn. In still
another
embodiment, the first yarn 22 may be an aramid (e.g., Kevlar made by DuPont
Corp. of
Wilmington, Delaware, USA) continuous multifilament yarn.
Spool, as used herein, refers to a device used to provide either temporary or
permanent storage for a yarn 20. First spool 100, as used herein, refers to a
spool
used to provide either temporary or permanent storage for a first yarn 22.
Second spool
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110, as used herein, refers to a spool used to provide either temporary or
permanent
storage for a second yarn 24. Third spool 120, as used herein, refers to a
spool used to
provide either temporary or permanent storage for a third yarn 26.
Pirn, as used herein, refers to a device used to provide either temporary or
permanent storage for a yarn 20. First pirn 105, as used herein, refers to a
pirn used to
provide either temporary or permanent storage for a first yarn 22. Second pirn
115, as
used herein, refers to a pirn used to provide either temporary or permanent
storage for
a second yarn 24. Third pirn 125, as used herein, refers to a pirn used to
provide either
temporary or permanent storage for a third yarn 26. In one embodiment of the
present
invention, a yarn 20 is unwound from a spool and then wound onto a pirn in
order to
ensure snag-free delivery of the yarn. In another embodiment of the present
invention,
a yarn is wound onto a pirn into a cocoon shape (Fig. 3) in order to ensure
snag-free
delivery of the yarn.
Second yarn 24, as used herein, refers to a yarn, as described above, that is
either a synthetic yarn, a natural yarn or a combination thereof. In one
embodiment of
the present invention, the second yarn 24 may be comprised of filaments 30
having a
first twist in either the "S" 40 or "Z" 35 direction. In another embodiment,
the second
yarn 24 may be comprised of fibers having a first twist in either the "S" 40
or "Z" 35
direction. The second yarn 24 may be comprised of materials including, but not
limited
to, cotton, linen, alpaca, angora, mohair, llama, cashmere, silk, camel, yak,
possum,
qiviut, cat, dog, wolf, rabbit, buffalo hair, polyamides, polyolefins,
polyesters, acrylics,
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cellulosics, or combinations thereof. In one embodiment of the present
invention, the
second yarn 24 may be a continuous multifilament yarn. In another embodiment,
the
second yarn 24 may be a nylon continuous multifilament yarn.
Synthetic yarn, as used herein, refers to a yarn comprised of synthetic fibers
and/or filaments obtained from man-made sources. Synthetic fibers/filaments,
as used
herein, refers to fibers/filaments made of polymers that do not occur
naturally but
instead are produced from by-products of petroleum or natural gas. Synthetic
fibers/filaments may be produced from fiber-forming substances including, but
not
limited to, (1) polymers synthesized from chemical compounds; (2) modified or
transformed natural polymers; and (3). Synthetic fibers/filaments include, but
are not
limited to, polyamides, polyolefins, polyesters, acrylics, cellulosics,
acetates, rayons,
fiberglass, or combinations thereof.
Natural yarn, as used herein, refers to a yarn comprised of natural fibers
and/or
filaments obtained from non-man made sources. Natural fibers, as used herein,
refer to
any hair-like raw material directly obtainable from an animal, vegetable or
mineral
source which may be spun into a yarn. The only filament that is produced in
nature is
silk. Most textile fibers are slender, flexible, and relatively strong. They
are elastic in
that they stretch when put under tension and then partially or completely
return to their
original length when the tension is removed. Natural fibers include, but are
not limited
to, cotton, linen, alpaca, angora, mohair, llama, cashmere, camel, yak,
possum, qiviut,
cat, dog, wolf, rabbit, buffalo hair, or asbestos. Natural filaments include
silk.
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Third yarn 26, as used herein, refers to a yarn 20, as described above, that
is
either a synthetic yarn, a natural yarn, or a combination thereof. In one
embodiment of
the present invention, the third yarn 26 may be comprised of filaments 30
having a first
twist in either the "S" 40 or "Z" 35 direction. In another embodiment, the
third yarn 26
may be comprised of fibers having a first twist in either the "S" 40 or "Z" 35
direction.
The third yarn 26 may be comprised of materials including, but not limited to,
cotton,
linen, alpaca, angora, mohair, llama, cashmere, silk, camel, yak, possum,
qiviut, cat,
dog, wolf, rabbit, buffalo hair, polyamides, polyolefins, polyesters,
acrylics, cellulosics,
or combinations thereof. In one embodiment of the present invention, the third
yarn 26
may be a continuous multifilament yarn. In another embodiment, the third yarn
26 may
be a nylon continuous multifilament yarn.
Twist, as used herein, refers to the spiral arrangement of the filament(s)
and/or
fibers around the axis of the yarn. Twist may be produced by revolving one of
a
filament/fiber strand while the other end is held stationary. The twist binds
the
filaments/fibers together and enhances the strength of the yarn. The direction
of the
twist is described as S-twist 40 and Z-twist 35. A yarn has S-twist 40 if,
when held in a
vertical position, the spirals conform to the direction of slope of the
central portion of the
letter "S". A yarn has Z-twist 35 if, when held in a vertical position, the
direction of
spirals conforms to the slope of the central portion of the letter "Z." In one
embodiment,
the twist may refer to a first twist which may be in either the "S" 40 or "Z"
35 direction.
In another embodiment, the twist may refer to a second twist which may be a
twist in the
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opposite direction as the first twist. In still another embodiment, the twist
may refer to a
third twist which may be a twist in either the same or the opposite direction
as the first
twist.
In one embodiment of the present invention, the first yarn 22, the second yarn
24
and the third yarn 26 each have a twist in a first direction in the range of
8.0 to 12.0
turns per inch. In another embodiment, the first yarn 22, the second yarn 24
and the
third yarn 26 each have a twist in a first direction in the range of 9.0 to
10.5 turns per
inch. In still another embodiment, the first yarn 22, the second yarn 24 and
the third
yarn 26 each have a twist in a first direction of 9.2 turns per inch.
In one embodiment, the first yarn 22, the second yarn 24 and the third yarn 26
are combined together with a twist in a second direction in the range of 4.0
to 8.0 turns
per inch to form a three-ply thread 50. In another embodiment, the first yarn
22, the
second yarn 24 and the third yarn 26 are combined together with a twist in a
second
direction in the range of 4.5 to 7.0 turns per inch to form a three-ply
thread. In yet
another embodiment, the first yarn 22, the second yarn 24 and the third yarn
26 are
combined together with a twist in a second direction of 5.0 turns per inch to
form a
three-ply thread 50.
Bonding agent, as used herein, refers to a material, such as an adhesive, used
to
bond filaments and or fibers to one another. Bonding agents may include, but
are not
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limited to, polyurethanes, polyethylene terephthalates, polyacrylics, nylons
and other
conventional fiber bonding compositions.
Multifilament yarn, as used herein, refers to a filament yarn, as described
above,
comprised of two or more filaments assembled with or without a twist. In one
embodiment of the present invention, the first yarn 22, second yarn 24 and
third yarn 26
are continuous multifilament yarns.
Dyeable, as used herein, refers to the ability of a fiber, filament, thread,
yarn, or
combination thereof to be colored with either natural or synthetic dyes.
Dyeing
processes include, but are not limited to, batik, chain dyeing, cross dyeing,
high-
temperature dying, ingrain, jet dyeing, mass-colored, muff dyeing, package
dyeing, pad
dyeing, piece dyeing, pressure dyeing, reserve dyeing, short-liquor dyeing,
skein
dyeing, solution dyeing, solvent dyeing, space dyeing, spin-dyeing, stock
dyeing,
thermal fixation, union dyeing, yarn dyeing, or combinations thereof. In one
embodiment of the present invention, the fire resistant thread 10 is dyeable.
Denier, as used herein, refers to the weight in grams of 9,000 meters of
filament
or filament yarn. For example, if 9,000 meters of a yarn weigh 15 grams, it is
a 15-
denier yarn; if 9,000 meters of a yarn weigh 100 grams, it is a 100-denier
yarn, and
much coarser than the 15-denier yarn. Thus a smaller number indicates a finer
yarn. In
one embodiment of the present invention, the deniers of the first and second
yarns are
roughly equal to one another. In another embodiment, the deniers of the first,
second,
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and third yarns are roughly equal to one another. In another embodiment, the
denier for
the first yarn 22, second yarn 24 and third yarn 26 is between 50 and 450. In
still
another embodiment, the denier for the first yarn 22, second yarn 24 and third
yarn 26 is
between 125 and 250. In still another embodiment, the denier for the first
yarn 22,
second yarn 24 and third yarn 26 is between 175 and 225. In still another
embodiment,
the denier for the first yarn 22, second yarn 24 and third yarn 26 is 80. In
still another
embodiment, the denier for the first yarn 22, second yarn 24 and third yarn 26
is 200. In
still another embodiment, the denier for the first yarn 22, second yarn 24 and
third yarn
26 is 400.
Filament count, as used herein, refers to the number of individual filaments
that
make up a thread or yarn. In one embodiment of the present invention, the
filament
count for the first yarn 22, second yarn 24 and third yarn 26 is between 30
and 75. In
another embodiment, the filament count for the first yarn 22, second yarn 24
and third
yarn 26 is between 40 and 65. In yet another embodiment, the filament count
for the
first yarn 22, the second yarn 24 and the third yarn 26 is 40. In still
another
embodiment, the filament counts of the second 24 and third yarns 26 are
roughly equal
to one another. In still another embodiment, the filament count of the first
yarn 22 is
substantially different to the filament counts of the second 24 and third
yarns 26. In still
another embodiment, the filament count of the first yarn 22 is roughly equal
to the
filament count of the second 24 and third yarns 26.
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The present invention may be realized in the form of numerous embodiments.
One embodiment of the present invention discloses a method for producing a
fire
resistant thread comprising the steps of: unwinding a first yarn 22 being a
fire resistant
polymer from a first spool 100; winding the first yarn 22 onto a first pirn
105; unwinding
a second yarn 24 being a synthetic and/or natural yarn from a second spool
110;
winding the second yarn 24 onto a second pirn 115; unwinding a third yarn 26
being a
synthetic and/or natural yarn from a third spool 120; winding the third yarn
26 onto a
third pirn 125; unwinding the first yarn 22, the second yarn 24, and the third
yarn 26
from the first pirn 105, the second pirn 115 and the third pirn 125;
tensioning and then
twisting the first yarn 22, the second yarn 24 and the third yarn 26 each in a
first
direction; tensioning and then twisting the first yarn 22, the second yarn 24
and the third
yarn 26 together in a second direction to form a three-ply thread 50; coating
the three-
ply thread 50 with a bonding agent in order to form the fire resistant thread
10; and
collecting the fire resistant thread 10.
In one embodiment of the above method (illustrated in Figure 3), the first
yarn 22
is wound onto the first pirn 105 in a cocoon shape, the second yarn 24 is
wound onto
the second pirn 115 in a cocoon shape and the third yarn 26 is wound onto the
third pirn
125 in a cocoon shape. In another embodiment of the above method, the fire
resistant
polymer is selected from the group comprising: an aramid, a polyester
polyarylate,
PBO, melamine formaldehyde, or combinations thereof. In still another
embodiment of
the above method, the second yarn 24 and the third yarn 26 are selected from
the
group comprising: cotton, linen, polyamides, polyolefins, polyesters,
acrylics,
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cellulosics, or combinations thereof. In yet another embodiment of the above
method,
the first 22, second 24 and third 26 yarns are continuous multifilament yarns.
In still
another embodiment of the above method, the fire resistant thread 10 is
dyeable.
In one embodiment of the above method for producing a fire resistant thread
10,
the first 22 and second 24 yarns each have a denier in the range of 50 to 450
and have
a filament count in the range of 30 to 75; the first yarn 22, the second yarn
24 and the
third yarn 26 each are tensioned to prevent any loops or breaks in the yarn
and having
a twist in a first direction being an "S" direction in the range of 8.0 to
12.0 turns per inch;
and the first yarn 22, the second yarn 24 and the third yarn 26 are tensioned
together to
prevent any loops or breaks in the yarns and then combined together with a
twist in a
second direction being a "Z" direction in the range of 4.0 to 8.0 turns per
inch to form
the three-ply thread 50.
In another embodiment of the above method for producing a fire resistant
thread
10, the first 22, second 24 and third 26 yarns each have a denier in the range
of 125 to
250 and have a filament count in the range of 40 to 65; the first yarn 22, the
second
yarn 24 and the third yarn 26 each are tensioned to prevent any loops or
breaks in the
yarn and having a twist in a first direction being an "S" direction in the
range of 9.0 to
10.5 turns per inch; and the first yarn 22, the second yarn 24 and the third
yarn 26 are
tensioned together to prevent any loops or breaks in the yarns and then
combined
together with a twist in a second direction being a "Z" direction in the range
of 4.5 to 7.0
turns per inch to form the three-ply thread 50.
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In another embodiment of the above method for producing a fire resistant
thread
10, the first yarn 22 is an aramid continuous multifilament yarn with a denier
of 200 and
a filament count of 40; the second 24 and third yarns 26 each being a nylon
continuous
multifilament yarn with a denier of 200 and a filament count of 40; the first
yarn 22, the
second yarn 24 and the third yarn 26 each are tensioned to prevent any loops
or breaks
in the yarns and have a twist in a first direction being an "S" direction of
9.2 turns per
inch; the first yarn 22, the second yarn 24 and the third yarn 26 are
tensioned together
at to prevent any loops or breaks in the yarns and then combined together with
a twist in
a second direction being a "Z" direction of 5.0 turns per inch to form the
three-ply thread
50.
In one embodiment of the above method for producing a fire resistant thread,
the
first yarn 22 is an aramid continuous multifilament yarn and the second yarn
24 and the
third yarn 26 each being a nylon continuous multifilament yarn.
In one embodiment of the above method for producing a fire resistant thread
10,
the coating step 4 may be comprised of the following steps: running the three-
ply
thread 50 from a supply creel 200; passing the three-ply thread 50 through a
first set of
stretch rollers 210; passing the three-ply thread 50 through a dipping tank
220 which
contains a bonding agent; passing the three-ply thread 50 through a squeegee
roller
230 to remove excess bonding agent; passing the three-ply thread 50 through a
first
oven 240 to dry the three-ply thread; passing the three-ply thread 50 through
a second
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oven 250 to dry the three-ply thread; passing the three-ply thread 50 through
a third
oven 260 to dry the three-ply thread; passing the three-ply thread 50 through
a second
set of stretch rollers 270; applying a lubricant 280 to the three-ply thread
50 resulting in
the fire resistant thread; and collecting the fire resistant thread 10 on a
spool 290. In
another embodiment of the above methods for producing a fire resistant thread
10, the
first oven 240 has a temperature in the range of 132 C to 143 C, the second
oven 250
has a temperature in the range of 143 C to 154 C and the third oven 260 has a
temperature in the range of 154 C to 166 C. In still another embodiment of the
above
methods for producing a fire resistant thread 10, the first oven 240 has a
temperature in
the range of 135 C to 140 C, the second oven 250 has a temperature in the
range of
140 C to 150 C and the third oven 260 has a temperature in the range of 150 C
to
162 C. In still another embodiment of the above methods for producing a fire
resistant
thread 10, the first oven 240 has a temperature in the range of 138 C to 142
C, the
second oven 250 has a temperature in the range of 142 C to 150 C and the third
oven
260 has a temperature in the range of 150 C to 158 C.
One embodiment of the present invention discloses a method for producing a
fire
resistant thread comprising the steps of: providing a first yarn 22 being a
fire resistant
polymer yarn; providing a second yarn 24 being a synthetic and/or natural
yarn; twisting
the first yarn 22 and the second yarn 24 each in a first direction; twisting
the first yarn 22
and the second yarn 24 together in a second direction to form a two-ply
thread; coating
the two-ply thread with a bonding agent in order to form the fire resistant
thread;
collecting the fire resistant thread. In one embodiment of the present
invention the fire
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resistant polymer yarn is selected from the group comprising: an aramid, a
polyester
polyarylate, PBO, melamine formaldehyde, or combinations thereof. In another
embodiment, the second yarn 24 is selected from the group comprising: cotton,
linen,
polyamides, polyolefins, polyesters, acrylics, cellulosics, or combinations
thereof. In still
another embodiment, the first 22 and second yarns 24 are continuous
multifilament
yarns. In yet another embodiment, the fire resistant thread 10 is dyeable. In
still
another embodiment, the first 22 and second yarns 24 each have a denier in the
range
of 50 to 450 and have a filament count in the range of 30 to 75. In yet
another
embodiment, the first yarn 22 is an aramid continuous multifilament yarn; and
the
second yarn 24 is a nylon continuous multifilament yarn.
In one embodiment of the present invention, the first twist process may take
place using a machine made by Thema Systems S.r.l. (Moglia, Italy), such as
the
DT/140 N Spindle or a similar machine. In another embodiment of the present
invention, each yarn may be tensioned using a ball yarn tensioner, varying the
spindle
speed (onto which a yarn is wound), the type of shape the yarn is wound into
on a
spindle, or a combination thereof. In another embodiment, the ball yarn
tensioner uses
ball bearings to increase or decrease the amount of tension on one or more
yarns. The
ball yarn tensioner is used to regulate the yarn reserve and compensate for
variations in
tension. The yarn reserve, as used herein, has the function of keeping the
tension of
the yarn constant by absorbing any irregularities during the unwinding. The
yarn
reserve is governed by the number and diameter of ball bearings placed within
the ball
yarn tensioner. The fewer the number of ball bearings placed within the ball
tensioner,
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the longer the reserve. The greater the number of ball bearings placed within
the ball
tensioner, the shorter the reserve. In one embodiment, the ball bearings may
be the
ones supplied by the machine manufacturer such as Thema Systems S.O. (Moglia,
Italy), for the DT/140 N Spindle or the R 325N DT/100 CE. In another
embodiment of
the present invention, the ball bearings may be made of any material,
including, but not
limited to, an aramid or a polyamide. In another embodiment, the ball bearings
may
range in diameter from 2-12mm. In another embodiment, the ball bearings may
range
in diameter from 4-8mm. In another embodiment, the ball bearings may be made
of an
aramid and have a diameter of 5mm or 10mm. In still another embodiment, the
ball
bearings may be made of a polyamide and have a diameter of 5mm or 10mm. In
another embodiment of the present invention, the number of ball bearings
placed within
the ball yarn tensioner is sufficient enough to prevent loops in a yarn 20 and
at the
same time insufficient enough to cause the yarn 20 to break. In one embodiment
of the
present invention, the number of ball bearings placed within the ball yarn
tensioner is
adjusted to compensate for factors selected from the group comprising:
temperature,
humidity, yarn type, yarn speed, or a combination thereof. In another
embodiment,
between 2 and 8 ball bearings are used to tension each yarn during the first
twist
process 2. In still another embodiment, between 2 and 8 ball bearings are used
to
tension the yarns during the second twist process 3. In another embodiment of
the
present invention, the number of ball bearings placed within the ball yarn
tensioner is
sufficient enough to prevent loops in the three yarns 22, 24 and 26 and at the
same time
insufficient enough to cause the yarns to break during the second twist
process 3. In
one embodiment of the present invention, the number of ball bearings placed
within the
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ball yarn tensioner is adjusted to compensate for factors selected from the
group
comprising: temperature, humidity, yarn type, yarn speed, or a combination
thereof
during the second twist process 3.
In one embodiment of the present invention, the second twist process 3
requires
two separate tension settings: the first tension setting is on the three yarns
as they
pass through a ball yarn tensioner (much like the individual yarns in the
first twist
process 2 described above) and the second tension setting is after the second
twist
process is completed and the 3-ply yarn is being wound on a pirn or spindle.
In another
embodiment, the second tension setting is achieved by adding weights to a
flyer placed
on top of the supply yarns. In still another embodiment, the weight placed on
top of the
flyer ranges from 20 to 60 grams. In yet another embodiment, the weight placed
on top
of the flyer ranges from 20 to 40 grams. In still another embodiment, the
weight placed
on top of the flyer is 20 grams. In yet another embodiment, the weight placed
on top of
the flyer ranges is 40 grams. In still another embodiment, the weight placed
on top of
the flyer is 60 grams.
In one embodiment of the present invention, the second twist process 3 may
take
place using a machine made by Ratti - Thema Systems S.r.l., such as the R 325N
DT/100 CE. In another embodiment, the second twist process 3 requires two
separate
tension settings: the first tension setting is on the three yarns as they pass
through a
ball yarn tensioner (much like the individual yarns in the first twist process
2) and the
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second tension setting is after the second twist process is completed and the
3-ply yarn
is being wound on a pirn or spindle.
In one embodiment, the above method may further comprise the steps of:
providing one or more additional yarns selected from the group comprising: a
fire
resistant polymer, a synthetic yarn, a natural yarn, or a combination thereof;
twisting the
additional yarn or yarns each in a first direction; twisting the first yarn,
the second yarn,
and the additional yarn(s) together in a second direction to form a multiple-
ply thread;
coating the multiple-ply thread with a bonding agent in order to form the fire
resistant
thread; and collecting the fire resistant thread.
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