Note: Descriptions are shown in the official language in which they were submitted.
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FLAME RESISTANT FABRICS WITH INCREASED STRENGTH
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No.
62/950,193, filed December 19, 2019, the entirety of which is hereby
incorporated by
reference.
FIELD
[0002] Embodiments of the present invention are directed to flame
resistant fabrics
formed of a plurality of spun body yarns and rip stops that extend between at
least
some of the spun body yarns in at least one of the warp or fill direction of
the fabric.
In some embodiments, the rip stops include at least two relatively tough
yarns, and
the relatively tough yarns include a core and a sheath.
BACKGROUND
[0003] Protective garments are designed to protect the wearer from
hazardous
environmental conditions the wearer might encounter. Such garments include
those
designed to be worn by firefighters and other rescue personnel, industrial and
electrical workers, and military personnel.
[0004] High tenacity, flame resistant fabrics have been developed
for military and
other applications. Examples of such fabrics are disclosed in U.S. Patent No.
RE42,309,
the entirety of which is herein incorporated by this reference. One particular
fabric of
the market today (sold under the tradertame Defender M Ripstop) is a plain
weave
fabric formed with spun body yarns having a blend of flame resistant rayon,
para-
aramid, and nylon fibers (specifically 65% flame resistant rayon/25% para-
aramid/10% nylon). Of particular concern in the design of fabrics for military
applications is fabric durability as defined by tensile (i.e. breaking)
strength and tear
strength. Rip stop yarns have been incorporated into these woven fabrics to
enhance
the strength of such fabrics. For example, the Defender M Ripstop fabric
includes
rip stops formed by two body yarns. More specifically, the two body yarns are
woven
as one in both the warp and fill directions at specified intervals. In this
way, the fabric
is formed entirely of the same yarns but constructed in a way to impart
strength to the
fabric.
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[0005] However, the high concentration of rayon fibers in the
fabric can
detrimentally impact the strength of the fabric. More specifically, rayon
fibers weaken
when exposed to water and moisture. Thus, the body yarns serving the rip stop
function are less able to impart strength to the fabric after such exposure.
Thus, there
is a need for a fabric that is better able to retain its strength properties
after exposure
to water and moisture all the while remaining flame resistant and cost-
effective.
SUMMARY
[0006] The terms "invention," "the invention," "this invention" and
"the present
invention" used in this patent are intended to refer broadly to all of the
subject matter
of this patent and the patent claims below. Statements containing these terms
should
not be understood to limit the subject matter described herein or to limit the
meaning
or scope of the patent claims below. Embodiments of the invention covered by
this
patent are defined by the claims below, not this summary. This summary is a
high-
level overview of various aspects of the invention and introduces some of the
concepts
that are further described in the Detailed Description section below. This
summary is
not intended to identify key or essential features of the claimed subject
matter, nor is
it intended to be used in isolation to determine the scope of the claimed
subject mailer.
The subject matter should be understood by reference to the entire
specification of this
patent, all drawings and each claim.
[0007] In some embodiments, the flame resistant fabric has a warp
direction and a
fill direction. The flame resistant fabric includes a plurality of spun body
yarns each
formed of a body yarn fiber blend and provided in both the warp direction and
the
fill direction of the fabric. The fabric can also include a plurality of rip
stops extending
between at least some of the spun body yarns in at least one of the warp
direction or
the fill direction of the fabric. In some embodiments, each rip stop includes
at least
two relatively tough yarns and each relatively tough yarn includes a core and
a sheath.
In some embodiments, the core includes an 100% aramid spun yarn and the sheath
includes a sheath fiber blend.
[0008] In some embodiments, the flame resistant fabric has a warp
direction and a
fill direction. The flame resistant fabric includes a plurality of spun body
yarns each
formed of a body yarn fiber blend and provided in both the warp direction and
the
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fill direction of the fabric, where in some embodiments the body yarn fiber
blend
includes 50-80% FR rayon fibers, 15-40% aramid fibers, and 5-20% nylon fibers.
The
fabric can also include a plurality of rip stops extending between at least
some of the
spun body yarns in at least one of the warp direction or the fill direction of
the fabric.
In some embodiments, each rip stop includes at least two relatively tough
yarns
formed of a core and a sheath. In some embodiments, the core includes an 100%
aramid spun yarn and the sheath includes a sheath fiber blend including 50-80%
FR
rayon fibers, 15-40% aramid fibers, and 5-20% nylon fibers. In some
embodiments, five
to twenty-five body yarns are interposed between adjacent rip stops in the at
least one
of the warp direction or the fill direction.
[0009] In some embodiments, the flame resistant fabric has a warp
direction and a
fill direction and includes a plurality of spun body yarns provided in both
the warp
direction and the fill direction of the fabric. In some embodiments, the spun
body
yarns are formed of a body yarn fiber blend that includes 50-80% FR rayon
fibers, 15-
40% para-aramid fibers, and 5-20% nylon fibers. The fabric can also include a
plurality
of rip stops extending between at least some of the spun body yarns in both
the warp
direction and the fill direction of the fabric. In some embodiments, at least
some of
the plurality of rip stops are formed of two relatively tough yarns that
include a core
and a sheath. In some embodiments, the core includes an 100% para-aramid spun
yarn and the sheath includes a sheath fiber blend including 50-80% FR rayon
fibers,
15-40% para-aramid fibers, and 5-20% nylon fibers. In some embodiments, the
body
yarn fiber blend and the sheath fiber blend are substantially identical, ten
to twenty
body yarns are interposed between adjacent rip stops in the warp direction and
the
fill direction of the fabric, and the fabric has a weight between 5-7 ounces
per square
yard, inclusive.
DETAILED DESCRIPTION
[0010] The subject matter of embodiments of the present invention
is described
here with specificity to meet statutory requirements, but this description is
not
necessarily intended to limit the scope of the claims. The claimed subject
matter may
be embodied in other ways, may include different elements or steps, and may be
used
in conjunction with other existing or future technologies. This description
should not
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be interpreted as implying any particular order or arrangement among or
between
various steps or elements except when the order of individual steps or
arrangement
of elements is explicitly described.
[0011] Disclosed are flame resistant fabrics formed with a
plurality of flame
resistant body yarns that form a body of the fabric and a plurality of
relatively tough
yarns provided in discrete positions within the fabric body to help impart
strength to
the fabric. Embodiments of the present invention replace the rip stop body
yarns with
a different yarn that is less apt to degrade or weaken when exposed to water
and
moisture and thus able to continue to impart the necessary strength after such
exposure.
[0012] Embodiments of the fabrics disclosed herein are flame
resistant in
compliance with GL-PD-07-12, Rev. 9 (Purchase Description: Cloth, Flame
Resistant,
2016, incorporated herein by reference) and MIL-PRF-32635: Cloth, Flame
Resistant
(2019, incorporated herein by reference), both of which require that the
fabric pass a
number of different performance tests, including compliance with the thermal
protective requirements of having a 4 inch (or less) char length and a 2
second (or less)
afterflame when measured pursuant the testing methodology set forth in ASTM
D6413 - Standard Test Method for Flame Resistance of Textiles (Vertical Test)
(2015 edition,
the entirety of which is hereby incorporated by reference).
[0013] To test for char length and afterflame, a fabric specimen is
suspended
vertically over a flame for twelve seconds. The fabric must self-extinguish
within two
seconds (i.e., it must have a 2 second or less afterflame). After the fabric
self-
extinguishes, a specified amount of weight is attached to the fabric and the
fabric lifted
so that the weight is suspended from the fabric. The fabric will typically
tear along
the charred portion of the fabric. The length of the tear (i.e., the char
length) must be
4 inches or less when the test is performed in both the machine/warp and cross-
machine/weft directions of the fabric. A fabric sample is typically tested for
compliance both before it has been washed (and thus when the fabric still
contains
residual - and often flammable - chemicals from finishing processes) and after
a
certain number of launderings.
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[0014] The body yarns comprise spun yarns that are constructed of
flame resistant
material(s). In some embodiments, the body yarns are formed with inherently FR
staple fibers or staple fibers that have been treated to be flame resistant.
Exemplary
FR and non-FR materials useful for forming the body yarns of the invention
include,
but are not limited to, aramids (including para-aramid and meta-aramid);
polybenzimidazole ("PBr); polybenzoxazole ("PBO"); mod acrylic; poly{2,6-
diiimidazo[4,5-b:40;50-e]-pyridinylene-1,4(2,5-dihydroxy)phenylenel ("PIPD");
ultra-
high molecular weight ("UHMVV") polyethylene; UHM VV polypropylene; polyvinyl
alcohol; polyacrylonitrile; liquid crystal polymer; glass; nylon; carbon;
silk;
polyamide; polyester; and natural and synthetic cellulosics (e.g., cotton,
rayon,
acetate, triacetate, and lyocell fibers, as well as their flame resistant
counterparts FR
cotton, FR rayon, FR acetate, FR triacetate, and FR lyocell), TANLON' fibers
(available from Shanghai Tanlon Fiber Company), wool, melamine (such as
BASOFILTM, available from Basofi I Fibers), polyetherimide, polyethersulfone,
pre-
oxidized acrylic, polyamide-imide fibers such as KERMEL",
polytetrafluoroethylene,
polyvinyl chloride, polyetheretherketone, polyetherim ide fibers, polychlal,
polyimide, polyimideamide, polyolefin, polyacrylate, and any combination or
blend
thereof.
[0015] Examples of para-aramid materials include KEVLARTM
(available from
DuPont), TECHNORA' (available from Teijin Twaron BV of Arnheim, Netherlands),
and TWARON (also available from Teijin Twaron By). Examples of meta-aramid
materials include NOMEX' (available from DuPont), CONEXTM (available from
Teijin), and Kermel (available from Kermel). An example of a suitable
modacrylic
material is PROTEX" available from Kaneka Corporation of Osaka, Japan. An
example of a PIPD material includes M5 (Dupont). Examples of UHMW polyethylene
materials include polymer material is VECTRAW M (available from Kuraray).
Examples of suitable rayon materials are ViscoseTM and ModalTM by Lenzing,
available
from Lenzing Fibers Corporation. An example of an FR rayon material is Lenzing
FRTM, also available from Lenzing Fibers Corporation. Examples of lyocell
material
include TENCEL G 100' and TENCEL A100TM, both available from Lenzing Fibers
Corporation.
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[0016] In some embodiments, the body yarns are a blend of at least
rayon, aramid,
and nylon fibers, such as 50-80% FR rayon fibers, 15-40% aramid fibers (e.g.,
para-
aramid fibers), and 5-20% nylon fibers. In some embodiments, the body yarns
have
the same blend as the body yarns in the Defender M Ripstop fabric
(specifically 65%
FR rayon/25% para-aramid/10% nylon). In other embodiments, the body yarns have
a blend of 70% FR rayon, 20% para-aramid, and 10% nylon. Other fibers could be
included in the body yarns. Each end of the body yarns may be formed of a
single
body yarn or multiple body yarns may be plied or otherwise combined to form an
end.
[0017] In addition to the body yarns, relatively tough yarns are
provided in
discrete rip stop locations within the fabric. As is known in the art,
"toughness" is a
property that pertains to a material's (in this case a yarn's) ability to
resist breakage.
The term "relatively tough" is used herein to describe yarns that have higher
toughness than the remainder of the yarns (i.e., body yarns) of the fabric.
[0018] The relatively tough yarns can be any type of yarn,
including, but not
limited to, spun, filament, stretch broken, and corespun yarns. In some
embodiments,
the relatively tough yarns are devoid of filament yarns. Materials useful in
the
relatively tough yarns include, but are not limited to, the same fibers
identified above
for use in the body yarns. The relatively tough yarns can include any
combination of
FR/non-FR materials, as long as the overall fabric is flame resistant and/or
satisfies
the applicable or desired standards for flame resistant fabrics (e.g., GL-PD-
0742, Rev.
9). Each end of the relatively tough yarns may be formed of a single yarn or
multiple
yarns may be combined, coupled, or covered (i.e., plied, ply twist, wrapped,
coresheath, coverspun, etc.) to form an end.
[0019] In some embodiments, the relatively tough yarns include
aramid (e.g., para-
aramid) content to impart the necessary strength to the fabric. For example,
in one
embodiment the relatively tough yarns include a 100% aramid (e.g., para-
aramid)
spun yarn. While the 100% aramid spun yarn may alone form the relatively tough
yarn, in other embodiments it is plied with another yarn to form a relatively
tough
yarn. For example, in one embodiment a 100% aramid spun yarn is plied with a
body
yarn to form a relatively touch yarn.
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[0020] In still another embodiment, the relatively tough yarns are
spun yarns
having a blend of flame resistant staple fibers, such as those disclosed
above. In a
more specific embodiment, the relatively tough yarns are spun yarns formed of
a
blend of aramid and FR rayon fibers (e.g., 50/50 blend).
[0021] In still another embodiment, the relatively tough yarns are
corespun yarns
having a core yarn about which a plurality of individual staple fibers are
spun to form
a fiber sheath that surrounds the core yarn. By way of example, the staple
fibers can
be spun around the core yarn using a dref spin procedure or air jet spinning
process.
The core yarn and staple fibers can be one or more of the various materials
identified
above. In one embodiment, the core yarn is a 100% aramid (e.g., para-aramid)
spun
yarn. The fiber sheath may be formed of the same blend of fibers as the body
yarns.
In another embodiment, the fiber sheath is formed of a different fiber blend,
such as a
blend of FR rayon and nylon (e.g., 90/10 blend).
[0022] The flame resistant fabric described herein may include the
body yarns and
the relatively tough yarns in any combination or orientation. For example, in
some
examples of the invention, the fabric may be a woven fabric that includes a
warp
direction and a fill direction. The body yarns will typically be provided in
both the
warp and fill direction. However, the relatively tough yarns may be included
in only
the warp direction, in only the fill direction, or in both the warp and fill
direction so
as to form a grid pattern within the fabric. Any desirable weave (e.g., plain,
twill) or
knit (e.g., single, double, plain, interlock) pattern may be used.
[0023] The relatively tough yarns may be located in the fabric
relative to the body
yarns in any desired ratio. The number of relatively tough yarns used in a rip
stop as
well as the frequency of the rip stops within the fabric may depend on the
desired
strength properties of the fabric and may be the same or different within
and/or
between the warp and/or fill direction of the fabric. Any number of relatively
tough
yarns greater than one may be used in each rip stop, and the number of
relatively
tough yarns within each rip stop need not be the same throughout the fabric.
By way
only of example, two relatively tough yarns, three relatively tough yarns,
four
relatively tough yarns, etc. may be used in a rip stop. Rip stops may be
provided in
either or both the warp and fill directions for every 40 body yarns, 35 body
yarns, 30
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body yarns, 25 body yarns, 20 body yarns, 15 body yarns, 10 body yarns, 5 body
yarns,
4 body yarns, 3 body yarns, 2 body yarns, and 1 body yarn. The frequency at
which
rip stops are provided may be the same or different (1) within a direction of
the fabric
and/or (2) in different directions of the fabric. In some embodiments, at
least two
relatively tough yarns but less than 4 relatively tough yarns form a rip stop
and
between 5 to 30 body yarns, inclusive; between 5 and 25 body yarns, inclusive;
between 5 and 20 body yarns, inclusive; between 5 and 15 body yarns,
inclusive;
between 5 and 10 body yarns, inclusive; between 10 and 30 body yarns,
inclusive;
between 10 and 25 body yarns, inclusive; between 10 and 20 body yarns,
inclusive;
and between 10 and 15 body yarns, inclusive are provided between adjacent rip
stops
in one or both directions of the fabric.
[0024] In some embodiments, the fabrics disclosed herein have a
weight between
2-12 ounces per square yard ("osy"), inclusive; 3-10 osy, inclusive; 3-9 osy,
inclusive;
3-8.5 osy, inclusive; 4-8 osy, inclusive; 4-7.5 osy, inclusive; 4-7 osy,
inclusive; 5-7 osy,
inclusive; 5.5-7 osy, inclusive; or 6-7 osy, inclusive. In some embodiments,
the fabric
weight is 6-7 osy, inclusive, and/or is less than or equal to 7 osy and/or
less than or
equal to 6.5 osy.
[0025] Specific, non-limiting embodiments of the invention are as
follows:
[0026] Inventive Fabric 1 ("IF1"): A 6.5 osy woven fabric formed
with (1) spun
body yarns having a fiber blend of 70% FR rayon/20% para-aramid/10% nylon and
(2) relatively tough yarns that were corespun yarns having a single 30 cotton
count
(English) 100% para-aramid spun core yarn and a fiber sheath of 70% FR
rayon/20%
para-aramid/10% nylon. The body yarns and relatively tough yarns were provided
in both the warp and fill directions in a body yarn to relatively tough yarn
ratio of 19:2
in the warp and 10:2 in the fill, meaning that a rip stop of two relatively
tough yarns
followed nineteen body yarns in a repeating pattern across the warp direction
and a
rip stop of two relatively tough yarns followed ten body yarns in a repeating
pattern
across the fill direction. The warp and fill densities were 69 ends/inch and
59
picks/inch, respectively.
[0027] Inventive Fabric 2 ("IF2"): A 6.5 osy woven fabric formed
with (1) spun
body yarns having a fiber blend of 70% FR rayon/20% para-aramid/10% nylon and
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(2) relatively tough yarns that were corespun yarns having a single 30 cotton
count
(English) 100% para-aramid spun core yarn and a fiber sheath of 90% FR
rayon/10%
nylon. The body yarns and relatively tough yarns were provided in both the
warp
and fill directions in a body yarn to relatively tough yarn ratio of 19:2 in
the warp and
10:2 in the fill (as described above with respect to Inventive Fabric 1). The
warp and
fill densities were 69 ends/inch and 59 picks/inch, respectively.
[0028] Inventive Fabric 3 ("IF3"): A 6.5 osy woven fabric formed
with (1) spun
body yarns having a fiber blend of 65% FR rayon/25% para-aramid/10% nylon and
(2) relatively tough yarns that were corespun yarns having a single 30 cotton
count
(English) 100% para-aramid spun core yarn and a fiber sheath of 65% FR
rayon/25%
para-aramid/10% nylon. Only body yarns were provided in the warp direction.
Both
body yarns and relatively tough yarns were provided in the fill direction in a
body
yarn to relatively tough yarn ratio of 10:2 in the fill direction, meaning
that a rip stop
of two relatively tough yarns followed ten body yarns in a repeating pattern
across
the fill direction. The warp and fill densities were 69 ends/inch and 59
picks/inch,
respectively.
[0029] The tensile and tear strengths of Inventive Fabrics 1-3 were
tested in
compliance with GL-PD-07-12, Rev. 9 and compared against the Defender M
Ripstop fabric described above. Tensile strength is the force required to
break a fabric
under a load, and is measured in accordance with ASTM D5034 - 09: Standard
Test
Method for Breaking Strength and Elongation of iText-ile Fabrics (Grab Test)
(2013 edition,
incorporated herein by this reference). According to this method, a specimen
is
mounted centrally in clamps of a tensile machine and a force is applied until
the
specimen breaks. Values for the breaking force and the elongation of the test
specimen
are obtained from machine scales, dials, autographic recording charts, or a
computer
interfaced with the testing machine. The results are reported in pounds force
(lbf).
[0030] Tear strength is a measure of the amount of force required
to propagate in
a fabric a tear after its initiation. The tear strength of fabrics is measured
pursuant to
ASTM D1424 - 09 (Standard Test Method for Tearing Strength of Fabrics by
Falling-
Pendulum (Elinendorf-Type) Apparatus (2013 edition), incorporated by
reference), and
the results are reported in pounds force (lbf).
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[0031] Pursuant to ASTM D1424-09, a slit of a specified size is cut
into a fabric
sample of a specified size. A clamp positioned on the fabric sample on each
side of
the slit to support the fabric sample. A weighted pendulum is released and
swings
down to apply a force to the fabric sample. The amount of force required to
propagate
the existing tear in the fabric is measured and that amount of force
represents the tear
strength of the fabric.
[0032] The testing results are reflected in Table 1.
TABLE 1
GL-PD-07-12 Rev.
Defender M
Test
IF1 IF2 IF3 9 Type III
Ripstop
Method
Requirements*
O.A. Width (in.) 66.3 66.7 66.9 66.8
ASTM
Cuttable Width 65.0 65.9 66.0 65.9
D 3774
Weight (osy) 6.6 6.3 6.3 6.5 6.0 - 7.0
ASTM
D 3776
Construction
(EP! x PPI)
EPI 75 73 74 74 60
PPI 56 54 53 56 50
Tensile
ASTM
Strength (lbf)
D 5034
Dry
Warp 163 170 171 169 110
Fill 114 122 120 130 100
Wet
Warp 142 148 149 149
N/A
Fill 105 111 108 116
Elmendorf Tear
ASTM
(lbf)
D 1424
Dry
Warp 17.8 18.7 19.5 22.4
12.0
Fill 14 23 19.7 21.9 10.0
Wet
Warp 13.2 14 15A 14A
8.0
Fill 8.8 17.2 14.6 16.9 6.0
*These requirements are the same for MIL-PRF-32635.
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[0033] As evidenced in Table 1, the tensile and tear strengths for
Inventive Fabrics
1-3 all complied with the Type III requirements of GL-PD-07-12, Rev. 9 and
exceeded
those of the Defender M Ripstop control fabric, both when wet and when dry.
[0034] Embodiments of the fabric disclosed herein may be used in
the construction
of a variety of protective garments, either by itself or in combination with
other fabrics,
and is not limited for use in military applications.
Examples
[0035] A collection of exemplary embodiments, including at least
some explicitly
enumerated as "Examples" providing additional description of a variety of
example
types in accordance with the concepts described herein are provided below.
These
examples are not meant to be mutually exclusive, exhaustive, or restrictive;
and the
invention is not limited to these example examples but rather encompasses all
possible
modifications and variations within the scope of the issued claims and their
equivalents.
[0036] Example 1. A flame resistant fabric having a warp
direction and a fill
direction, the fabric comprising a plurality of spun body yarns each formed of
a body
yarn fiber blend and provided in both the warp direction and the fill
direction of the
fabric, and a plurality of rip stops extending between at least some of the
spun body
yarns in at least one of the warp direction or the fill direction of the
fabric, wherein
each rip stop comprises at least two relatively tough yarns and wherein each
relatively
tough yarn comprises a core and a sheath, wherein the core comprises an 100%
aramid
spun yarn and the sheath comprises a sheath fiber blend.
[0037] Example 2. The flame resistant fabric of any of the
preceding or
subsequent examples or combination of examples, wherein the core comprises an
100% para-aramid spun yarn.
[0038] Example 3. The flame resistant fabric of any of the
preceding or
subsequent examples or combination of examples, wherein the sheath fiber blend
comprises FR rayon fibers, aramid fibers, and nylon fibers.
[0039] Example 4. The flame resistant fabric of any of the
preceding or
subsequent examples or combination of examples, wherein the sheath fiber blend
comprises 50-80% FR rayon fibers, 15-40% aramid fibers, and 5-20% nylon
fibers.
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[0040] Example 5. The flame resistant fabric of any of the
preceding or
subsequent examples or combination of examples, wherein the aramid fibers are
para-
aramid fibers.
[0041] Example 6. The flame resistant fabric of any of the
preceding or
subsequent examples or combination of examples, wherein the body yarn fiber
blend
and the sheath fiber blend are identical.
[0042] Example 7. The flame resistant fabric of any of the
preceding or
subsequent examples or combination of examples, wherein the body yarn fiber
blend
and the sheath fiber blend each comprises 50-80% FR rayon fibers, 15-40%
aramid
fibers, and 5-20% nylon fibers.
[0043] Example 8. The flame resistant fabric of any of the
preceding or
subsequent examples or combination of examples, wherein the body yarn fiber
blend
and the sheath fiber blend are identical.
[0044] Example 9. The flame resistant fabric of any of the
preceding or
subsequent examples or combination of examples, wherein five to twenty-five
spun
body yarns are interposed between adjacent rip stops in the at least one of
the warp
direction or the fill direction.
[0045] Example 10. The flame resistant fabric of any of the
preceding or
subsequent examples or combination of examples, wherein ten to twenty body
yarns
are interposed between adjacent rip stops in the at least one of the warp
direction or
the fill direction.
[0046] Example 11. The flame resistant fabric of any of the
preceding or
subsequent examples or combination of examples, wherein the plurality of rip
stops
extend between at least some of the spun body yarns in both the warp direction
and
the fill direction of the fabric.
[0047] Example 12. The flame resistant fabric of any of the
preceding or
subsequent examples or combination of examples, wherein the fabric comprises a
weight between 5-7 ounces per square yard, inclusive.
[0048] Example 13. The flame resistant fabric of any of the
preceding or
subsequent examples or combination of examples, wherein the flame resistant
fabric
is devoid of filament yarns.
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[0049] Example 14. A flame resistant fabric having a warp
direction and a fill
direction, the fabric comprising a plurality of spun body yarns each formed of
a body
yarn fiber blend and provided in both the warp direction and the fill
direction of the
fabric, wherein the body yarn fiber blend comprises 50-80% FR rayon fibers, 15-
40%
aramid fibers, and 5-20% nylon fibers, and a plurality of rip stops extending
between
at least some of the spun body yarns in at least one of the warp direction or
the fill
direction of the fabric, wherein each rip stop comprises at least two
relatively tough
yarns and wherein each relatively tough yarn comprises a core and a sheath,
wherein
the core comprises an 100% aramid spun yarn and the sheath comprises a sheath
fiber
blend comprising 50-80% FR rayon fibers, 15-40% aramid fibers, and 5-20% nylon
fibers, and wherein five to twenty-five body yarns are interposed between
adjacent
rip stops in the at least one of the warp direction or the fill direction.
[0050] Example 15. The flame resistant fabric of any of the
preceding or
subsequent examples or combination of examples, wherein the core comprises an
100% para-aramid spun yarn.
[0051] Example 16. The flame resistant fabric of any of the
preceding or
subsequent examples or combination of examples, wherein the 15-40% aramid
fibers
in the body yarn fiber blend and the sheath fiber blend comprise 15-40% para-
aramid
fibers.
[0052] Example 17. The flame resistant fabric of any of the
preceding or
subsequent examples or combination of examples, wherein the body yarn fiber
blend
and the sheath fiber blend are identical.
[0053] Example 18. The flame resistant fabric of any of the
preceding or
subsequent examples or combination of examples, wherein the plurality of rip
stops
extend between at least some of the spun body yarns in both the warp direction
and
the fill direction of the fabric.
[0054] Example 19. The flame resistant fabric of any of the
preceding or
subsequent examples or combination of examples, wherein the fabric comprises a
weight between 5-7 ounces per square yard, inclusive.
[0055] Example 20. A flame resistant fabric having a warp
direction and a fill
direction, the fabric comprising a plurality of spun body yarns each formed of
a body
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PCT/US2020/066038
yarn fiber blend and provided in both the warp direction and the fill
direction of the
fabric, wherein the body yarn fiber blend comprises 50-80% FR rayon fibers, 15-
40%
para-aramid fibers, and 5-20% nylon fibers, and a plurality of rip stops
extending
between at least some of the spun body yarns in both the warp direction and
the fill
direction of the fabric, wherein at least some of the plurality of rip stops
consist of two
relatively tough yarns and wherein each relatively tough yarn comprises a core
and a
sheath, wherein the core comprises an 100% para-aramid spun yarn and the
sheath
comprises a sheath fiber blend comprising 50-80% FR rayon fibers, 15-40% para-
aramid fibers, and 5-20% nylon fibers, wherein the body yarn fiber blend and
the
sheath fiber blend are substantially identical, wherein ten to twenty body
yarns are
interposed between adjacent rip stops in the warp direction and the fill
direction of
the fabric, and wherein the fabric comprises a weight between 5-7 ounces per
square
yard, inclusive.
[0056] Different arrangements of the components described above, as
well as
components and steps not shown or described are possible. Similarly, some
features
and subcombinations are useful and may be employed without reference to other
features and subcombinations. Embodiments of the invention have been described
for illustrative and not restrictive purposes, and alternative embodiments
will become
apparent to readers of this patent. Accordingly, the present invention is not
limited
to the embodiments described above or depicted in the drawings, and various
embodiments and modifications can be made without departing from the scope of
the
invention.
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