U.S. patent application number 10/967975 was filed with the patent office on 2006-04-20 for blended outer shell fabrics.
This patent application is currently assigned to Southern Mills, Inc.. Invention is credited to Christopher Garrington Frank Corner, Stan Jewell.
Application Number | 20060084337 10/967975 |
Document ID | / |
Family ID | 36181373 |
Filed Date | 2006-04-20 |
United States Patent
Application |
20060084337 |
Kind Code |
A1 |
Corner; Christopher Garrington
Frank ; et al. |
April 20, 2006 |
Blended outer shell fabrics
Abstract
The present disclose relates to blended outer shell fabrics. In
one embodiment, an outer shell fabric for use in firefighter
turnout gear includes a plurality of yarns that comprise at least
three different types of inherently flame resistant fibers. In
another embodiment, a fabric includes a blend of inherently flame
resistant fibers, the blend including a plurality of para-aramid
fibers, a plurality of meta-aramid fibers, and a plurality of
polybenzoxazole (PBO) fibers.
Inventors: |
Corner; Christopher Garrington
Frank; (US) ; Jewell; Stan; (Fayetteville,
GA) |
Correspondence
Address: |
THOMAS, KAYDEN, HORSTEMEYER & RISLEY, LLP
100 GALLERIA PARKWAY, NW
STE 1750
ATLANTA
GA
30339-5948
US
|
Assignee: |
Southern Mills, Inc.
|
Family ID: |
36181373 |
Appl. No.: |
10/967975 |
Filed: |
October 19, 2004 |
Current U.S.
Class: |
442/203 ;
442/209; 442/210 |
Current CPC
Class: |
Y10T 442/3228 20150401;
Y10T 442/335 20150401; A41D 31/08 20190201; D02G 3/443 20130101;
Y10T 442/3236 20150401; D03D 15/513 20210101; D10B 2331/021
20130101; Y10T 442/3179 20150401; D02G 3/047 20130101 |
Class at
Publication: |
442/203 ;
442/209; 442/210 |
International
Class: |
D03D 13/00 20060101
D03D013/00; D03D 15/00 20060101 D03D015/00 |
Claims
1. An outer shell fabric for use in firefighter turnout gear, the
outer shell fabric comprising: a plurality of yarns that comprise
at least three different types of inherently flame resistant
fibers.
2. The outer shell fabric of claim 1, wherein the three different
types of inherently flame resistant fibers comprise para-aramid
fibers, meta-aramid fibers, and polybenzoxazole (PBO) fibers.
3. The outer shell fabric of claim 1, wherein the fabric comprises
about 40% to about 70% para-aramid, about 10% to about 40%
meta-aramid, and about 5% to about 30% polybenzoxazole (PBO).
4. The outer shell fabric of claim 1, wherein the fabric comprises
about 60% para-aramid, about 20% meta-aramid, and about 20%
polybenzoxazole (PBO).
5. The outer shell fabric of claim 1, wherein the fabric comprises
a rip stop weave.
6. The outer shell fabric of claim 5, wherein the rip stop weave is
a two-end rip stop weave.
7. The outer shell fabric of claim 1, wherein the yarns have yarn
counts in the range of approximately 10-35 cc.
8. The outer shell fabric of claim 1, wherein the fabric has a
weight of about 5 ounces per square yard to about 10 ounces per
square yard.
9. The outer shell fabric of claim 1, wherein the fabric has a
tensile strength in the warp direction that exceeds 200 pounds and
a tensile strength in the filling direction that exceeds 175 pounds
after a 7 second exposure in accordance with the thermal protective
performance (TPP) test method defined in NFPA 1971, 2000
edition.
10. A fabric suitable for use in firefighter turnout gear, fabric
comprising: a blend of inherently flame resistant fibers, the blend
including: a plurality of para-aramid fibers; a plurality of
meta-aramid fibers; and a plurality of polybenzoxazole (PBO)
fibers.
11. The fabric of claim 10, wherein the fabric comprises about 40%
to about 70% para-aramid fibers, about 10% to about 40% meta-aramid
fibers, and about 5% to about 30% PBO fibers.
12. The fabric of claim 10, wherein the fabric comprises about 60%
para-aramid fibers, about 20% meta-aramid fibers, and about 20%
polybenzoxazole (PBO) fibers.
13. The fabric of claim 10, wherein the fabric comprises a rip stop
weave.
14. The fabric of claim 13, wherein the rip stop weave is a two-end
rip stop weave.
15. The fabric of claim 10, wherein the fabric comprises a
plurality of yarns, each yarn including para-aramid fiber,
meta-aramid fiber, and PBO fibers.
16. The fabric of claim 15, wherein the yarns have yam counts in
the range of approximately 10-35 cc.
17. The fabric of claim 10, wherein the fabric has a weight of
about-5 ounces per square yard to about 10 ounces per square
yard.
18. The fabric of claim 10, wherein the fabric has a tensile
strength in the warp direction that exceeds 200 pounds and a
tensile strength in the filling direction that exceeds 175 pounds
after a 7 second exposure in accordance with the thermal protective
performance (TPP) test method defined in NFPA 1971, 2000
edition.
19. A firefighter turnout garment, the garment comprising: a
thermal liner that forms an interior surface of the garment; a
moisture barrier that forms an intermediate layer of the garment;
and an outer shell that forms the exterior surface of the garment,
the outer shell comprising a fabric blend of inherently flame
resistant fibers, the blend including para-aramid fibers,
meta-aramid fibers, and polybenzoxazole (PBO) fibers.
20. The garment of claim 19, wherein the outer shell fabric
comprises about 40% to about 70% para-aramid fibers, about 10% to
about 40% meta-aramid fibers, and about 5% to about 30% PBO
fibers.
21. The garment of claim 19, wherein the outer shell fabric
comprises about 60% para-aramid fibers, about 20% meta-aramid
fibers, and about 20% polybenzoxazole (PBO) fibers.
22. The garment of claim 19, wherein the outer shell fabric
comprises a rip stop weave.
23. The garment of claim 22, wherein the rip stop weave is a
two-end rip stop weave.
24. The garment of claim 19, wherein the outer shell fabric
comprises a plurality of yarns, each yarn including para-aramid
fibers, meta-aramid fibers, and PBO fibers.
25. The garment of claim 24, wherein the yarns have yarn counts in
the range of approximately 10-35 cc.
26. The garment of claim 19, wherein the outer shell fabric has a
weight of about 5 ounces per square yard to about 10 ounces per
square yard.
27. The garment of claim 19, wherein the outer shell fabric has a
tensile strength in the warp direction that exceeds 200 pounds and
a tensile strength in the filling direction that exceeds 175 pounds
after a 7 second exposure in accordance with the thermal protective
performance (TPP) test method defined in NFPA 1971, 2000
edition.
28. The garment of claim 19, wherein the garment is one of a
jacket, trousers, and coveralls.
Description
BACKGROUND
[0001] Firefighters typically wear protective garments commonly
referred to in the industry as turnout gear. Turnout gear normally
comprises various garments including, for instance, coveralls,
trousers, and jackets. These garments usually include several
layers of material including, for example, an outer shell that
protects the wearer from flames, a moisture barrier that prevents
the ingress of water into the garment, and a thermal barrier that
insulates the wearer from extreme heat.
[0002] Turnout gear outer shells typically comprise woven fabrics
formed of one or two types of flame resistant materials. In
addition to shielding the wearer from flames, the outer shells of
firefighter turnout gear further provide abrasion resistance and
protection from sharp objects. In that the outer shell must
withstand exposure to flame and excessive heat, and must be
resistant to abrasion and tearing, it must be constructed of a
flame resistant material that is both strong and durable.
[0003] The selection process for the materials used to construct
outer shell fabrics, as with the selection process for other
fabrics, often involves balancing various factors. Such factors
include fabric performance as well as cost. For instance, outer
shell fabrics that primarily comprise lower-performance fibers are
normally less expensive than fabrics that include
higher-performance fibers. Although the fabrics that comprise
higher-performance fibers may provide greater protection, that
protection comes at a greater cost, both to the manufacturer and
the consumer.
[0004] In view of the above, it would be desirable to be able to
provide relatively inexpensive outer shell fabrics having
performance that approaches or even exceeds that of more expensive
outer shell fabrics.
SUMMARY
[0005] The present disclosure relates to blended outer shell
fabrics. In one embodiment, an outer shell fabric for use in
firefighter turnout gear includes a plurality of yarns that
comprise at least three different types of inherently flame
resistant fibers.
[0006] In another embodiment, a fabric includes a blend of
inherently flame resistant fibers, the blend including a plurality
of para-aramid fibers, a plurality of meta-aramid fibers, and a
plurality of polybenzoxazole (PBO) fibers.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The disclosed fabrics can be better understood with
reference to the following drawings. The components in the drawings
are not necessarily to scale.
[0008] FIG. 1 is a rear view of an example protective garment that
includes a blended outer shell fabric.
[0009] FIG. 2 is a schematic representation of a blended outer
shell fabric that can be used in the construction of the garment of
FIG. 1.
[0010] FIG. 3 is a schematic representation of an alternative
blended outer shell fabric that can be used in the construction of
the garment of FIG. 1.
DETAILED DESCRIPTION
[0011] As is described in the foregoing, it would be desirable to
be able to provide relatively inexpensive outer shell fabrics
having improved performance. As is described in the following, such
a result can be achieved with certain blends of inherently flame
resistant fibers. One such blend, for example, includes a blend of
para-aramid, meta-aramid, and polybenzoxazole (PBO) fibers. As is
described in greater detail below, such a blend provides
unexpectedly desirable physical properties at a relatively low
cost.
[0012] FIG. 1 illustrates an example protective garment 100. More
particularly, FIG. 1 illustrates a firefighter turnout coat that
can be donned by firefighter personnel when exposed to flames and
extreme heat. It is noted that, although a firefighter turnout coat
is shown in the figure and described herein, embodiments of this
disclosure pertain to protective garments and fabrics generally.
Accordingly, the identification of firefighter turnout gear is not
intended to limit the scope of the disclosure.
[0013] As is indicated in FIG. 1, the garment 100 generally
comprises an outer shell 102 that forms the exterior surface of the
garment, a moisture barrier 104 that forms an intermediate layer of
the garment, and a thermal liner 106 that forms the interior
surface (i.e., the surface that contacts the wearer) of the
garment. In that it forms the exterior surface of the garment 100,
the outer shell 102 preferably is constructed so as to be flame
resistant to protect the wearer against being burned. In addition,
the outer shell 102 preferably is strong and durable so as to be
resistant to abrasion and tearing during use in hazardous
environments.
[0014] FIG. 2 is a schematic detail view of an example blended
outer shell fabric 200 that can be used in the construction of the
protective garment 100, and more particularly the outer shell 102
shown in FIG. 1. It is noted, however, that the fabric 200 could be
used in the construction of other protective garments either by
itself or in combination with other fabrics. The example fabric 200
illustrated in FIG. 2 is a rip stop fabric that comprises a
plurality of body yarns 206, including picks 202 and ends 204, and
a plurality of rip stop yarns 208. Although a rip stop weave is
illustrated in FIG. 2 and is described herein, it will be
appreciated that other configurations could be used including, for
instance, a plain weave, a twill weave, or a variation on a
conventional rip stop weave (see, e.g., FIG. 3).
[0015] Generally speaking, the fabric 200 comprises a blend of
different inherently flame resistant materials. Typically, at least
three different inherently flame resistant materials are used to
construct the fabric 200 so as to obtain the distinct benefits of
each, whether they be performance or cost benefits. By way of
example, the yarns of the fabric 200, including one or more of the
picks 202, ends 204, and rip stop yarns 208, comprise a blend of
para-aramid fibers, meta-aramid fibers, and PBO fibers.
[0016] Example para-aramid fibers include those that are currently
available under the trademarks KEVLAR.RTM. (DuPont), and
TECHNORA.RTM. and TWARON.RTM. (Teijin). Example meta-aramid fibers
include those sold under the tradenames NOMEX T-450.RTM. (100%
meta-aramid), NOMEX T-455.RTM. (a blend of 95% NOMEX.RTM. and 5%
KEVLAR.RTM.), and NOMEX T-462.RTM. (a blend of 93% NOMEX.RTM., 5%
KEVLAR.RTM., and 2% anti-static carbon/nylon), each of which is
produced by DuPont. Example meta-aramid fibers also include fibers
that are currently available under the trademarks CONEX.RTM. and
APYEIL.RTM., which are produced by Teijin and Unitika,
respectively. Example PBO fibers include ZYLON.RTM. from
Toyobo.RTM..
[0017] It is noted that, for purposes of the present disclosure,
when a material name is used herein, the material referred to,
although primarily comprising the named material, may not be
limited to only the named material. For instance, the term
"meta-aramid fibers" is intended to include NOMEX.RTM. T-462
fibers, which, as is noted above, comprise relatively small amounts
of para-aramid fiber and anti-static fiber in addition to fibers
composed of meta-aramid material.
[0018] While a tri-blend of para-aramid, meta-aramid, and PBO
fibers has been explicitly identified, other inherently flame
resistant materials can be added to the blend, if desired. Such
other materials may, for example, include one or more of
polybenzimidazole (PBI), melamine, polyamide, polyimide,
polyimideamide, and modacrylic.
[0019] Moreover, non-inherently flame resistant materials can be
added to the blend, if desired. Examples of such materials include
cellulosic fibers, such as rayon, acetate, triacetate, and lyocell.
These cellulosic materials, although not naturally resistant to
flame, can be rendered flame resistant, if desired.
[0020] In cases in which para-aramid, meta-aramid, and PBO fibers
are used to construct the fabric 200, the fabric can, for example,
comprise about 40% to about 70% para-aramid, about 10% to about 40%
meta-aramid, and about 5% to about 30% PBO. As is described below,
one example blend is an approximately 60/20/20 blend of para-aramid
fibers, meta-aramid fibers, and PBO fibers, respectively.
[0021] The body yarns 206 typically comprise spun yarns that, for
example, each comprises a single yarn or two or more individual
yarns that are plied, or otherwise combined, together. By way of
example, the body yarns 206 comprise one or more yarns that each
have a yarn count (or "cotton count") in the range of approximately
5 to 60 cc, with 8 to 40 cc being preferred. In some embodiments,
the body yarns 206 can comprise two yarns that are plied together,
each having a yarn count in the range of approximately 10 to 35
cc.
[0022] The rip stop yarns 208 can have a construction similar to
those of the body yarns, but are provided in pairs that are woven
through the fabric 200 side-by-side as is illustrated in FIG. 2. In
some embodiments, rip stop yarns 208 can be different in
construction from the body yarns 206. For example, filament yarns
could be used in the construction of the rip stop yarns 208, if
desired. In other embodiments, filament yarns can be combined with
spun yarns or spun fiber to form rip stop yarns in the manner
described in U.S. patent application Ser. No. 10/165,795, which is
hereby incorporated by reference into the present disclosure. In
cases in which the rip stop yarns 208 have a construction that is
different than the body yarns 206, it is possible to use a single
yarn instead of two as is illustrated in FIG. 2. For example, if
the rip stop yarns 208 have a lower yarn count (and therefore
larger size) than the body yarns 206, then single rip stop yarns
208 may be enough to protect against propagation of fabric
tears.
[0023] The placement of the rip stop yarns 208 within the fabric
200 can be varied depending upon the desired physical properties.
In the embodiment shown in FIG. 2, the rip stop yarns 208 are
provided within the fabric 200 in a grid pattern in which several
body yarns 206 are placed between each consecutive pair of rip stop
yarns 208 in both the warp and filling directions of the fabric. By
way of example, a pair of rip stop yarns 208 is provided in the
fabric 200 in both the warp and filling directions of the fabric
for every approximately 7 to 9 body yarns 206. In some embodiments,
the grid pattern is configured to form a plurality of squares. To
accomplish this, a greater number of body yarns 206 may need to be
provided between consecutive rip stop yarn pairs in the one
direction (e.g., warp) as compared to the other direction (e.g.,
filling).
[0024] FIG. 3 is a schematic detail view of an alternative example
rip stop fabric 300 that can be used in the construction of the
protective garment 100. The fabric 300 is similar to the fabric 200
shown in FIG. 2 and therefore comprises body yarns 206 that form
the body of the fabric and that have composition and construction
similar to those described above with regard to FIG. 2. In the
fabric 300, however, three rip stop yarns 208 are woven through the
fabric together in a grid pattern within the fabric body to form a
three-end rip stop weave (as opposed to the two-end rip stop weave
shown in FIG. 2).
[0025] With the constructions described above, the fabrics 200, 300
have weights of about 5 to about 10 ounces per square yard
(osy).
[0026] As is noted above, unexpected results are achievable with
the blends described herein. More specifically, unexpectedly
desirable physical properties can be attained given the relatively
low cost of the fabric, which is dictated, in substantial part, by
the cost of the materials used to produce the fabric. In several
instances, the physical properties of the disclosed blends exceed
(i.e., are better than) those of competing fabrics and are
substantially lower in cost than "top-end" outer shell fabrics. A
specific example fabric having a construction within the parameters
identified in the foregoing is described in the following.
Example Fabric
[0027] A 60/20/20 blend of KEVLAR.RTM. T-970 (para-aramid),
NOMEX.RTM. T-462 (meta-aramid), and ZYLON.RTM. (PBO) was
constructed having a fabric weight of approximately 7.5 osy. The
fabric was formed as a two-end rip stop fabric (see, e.g., FIG. 2)
having 56 ends per inch and 51 picks per inch, with 9 ends provided
between each pair of rip stop yarns in the warp direction, and 7
picks provided between each pair of rip stop yarns in the filling
direction. Each of the yarns in the fabric (i.e., body and rip stop
yarns in both directions) comprised two 60/20/20
KEVLAR.RTM./NOMEX.RTM./ZYLON.RTM. yarns each having a yarn count of
21 cc (i.e., 21/2 yarns).
[0028] Once constructed, the example fabric was tested to determine
its physical and thermal properties. The results of the testing are
provided in Table I, in which the example fabric is designated as
the "Tri-Blend Fabric." Also included in this table are the test
results for other fabrics ("Comparison Fabrics A and B").
[0029] Comparison Fabric A comprised a 60/40 blend of KEVLAR.RTM.
T-970 and NOMEX.RTM. T-462 having a fabric weight of approximately
7.2 osy. The fabric was formed as a three-end rip stop fabric
having 56 ends per inch and 51 picks per inch, with 8 ends provided
between each group of three rip stop yarns in the warp direction,
and 8 picks provided between each group of three rip stop yarns in
the filling direction. Each of the yarns in the fabric (i.e., body
and rip stop yarns in both directions) comprised two 60/40
KEVLAR.RTM./NOMEX.RTM. yarns each having a yarn count of 21 cc
(i.e., 21/2 yarns).
[0030] Comparison Fabric B comprised a 60/40 blend of KEVLAR.RTM.
T-970 and PBI having a fabric weight of approximately 7.5 osy. The
fabric was formed as a two-end rip stop fabric having 44 ends per
inch and 39 picks per inch, with 9 ends provided between each pair
of rip stop yarns in the warp direction, and 7 picks provided
between each pair of rip stop yarns in the filling direction. Each
of the yarns in the fabric (i.e., body and rip stop yarns in both
directions) comprised two 60/40 KEVLAR.RTM./PBI yarns each having a
yarn count of 15 cc (i.e., 15/2 yarns).
[0031] As is indicated in Table I, the example fabric and the
comparison fabrics were tested for strength, thermal resistance,
and abrasion resistance. In terms of strength, the trap tear
strength of the fabrics was tested according to test method ASTM
D5733, as is required by NFPA 1971, 2000 edition (hereafter "NFPA
1971"), both before and after 5 washing cycles. In addition, the
fabrics were separately tested for tensile strength according to
test method ASTM D5034 prior to washing and thermal exposure, after
10 washing cycles, and after thermal exposure.
[0032] In terms of thermal resistance, the fabrics were exposed to
extreme temperatures for seven (7) seconds in accordance with the
thermal protective performance (TPP) test method described in NFPA
1971, and were tested for vertical flame in accordance with Federal
Test Method 191A as is required by NFPA 1971.
[0033] Finally, the fabrics were tested for abrasion resistance
using the Taber Abrasion Test in accordance with ASTM3884.
TABLE-US-00001 TABLE I Tri-Blend Comparison Comparison Fabric
Properties Fabric Fabric A Fabric B Trap Tear Strength (lbs) Warp
52.8 40.3 31.3 Fill 40.9 33.5 29.2 Trap Tear Strength (lbs)
(5.times. Wash) Warp 44 34.8 28.1 Fill 36.7 25.8 25.5 Tensile
Strength (lbs) Warp 435 308-305 302-260 Fill 406 305-287 237-220
Tensile Strength (lbs) (10.times. Wash) Warp 313 270-237 240-237
Fill 321 260-215 205-172 Tensile Strength (lbs) (after 7 sec TPP
exposure) Warp 223 78-75 117-105 Fill 187 90-73 85 TPP (cal/cm2)
Crosstech .RTM./Caldura .RTM. 40.6 38.4 41.2 Platinum SLNew
Crosstech .RTM./Caldura .RTM. 44 39.8 39.7 Platinum Crosstech
.RTM./3 layer 44.3 47.1 41.1 E89 .RTM. Crosstech .RTM./Q9 .RTM. 50
48.9 47.8 Vertical Flame After Flame (sec) 0 .times. 0 0 .times. 0
0 .times. 0 (W .times. F) Char Length (inch) 0.5 .times. 0.6 .54
.times. .43 .29 .times. .24 (W .times. F) Taber Abrasion (average
cycles to 933 350 367 first break)
[0034] As is evident from Table I, the example fabric ("Tri-Blend
Fabric") performed markedly better in terms of both trap tear
strength and tensile strength than Comparison Fabrics A and B.
Although improved performance could be expected over Comparison
Fabric A due to the presence of the PBO fiber in the Tri-Blend
Fabric, the magnitude of the strength increases resulting from only
20% PBO fiber is particularly surprising. For instance, the tensile
strength of the Tri-Blend Fabric tested to be as much as over 250%
greater than that of Comparison Fabric A.
[0035] Equally or even more surprising is the strength that the
Tri-Blend fabric exhibited after 7 seconds of TTP exposure as
compared to Comparison Fabric B. As is evident from the table, the
Tri-Blend fabric was approximately twice as strong as Comparison
Fabric B after such exposure. This strength difference was
unexpected at least in part because Comparison Fabric B contained a
significant amount of PBI, which is generally regarded as much more
resistant to thermal exposure than less expensive materials, such
as the meta-aramid of the Tri-Blend fabric.
[0036] In addition, marked improvement in abrasion resistance was
observed for the Tri-Blend Fabric. As is indicated in Table I, the
Tri-Blend Fabric exhibited an abrasion resistance that is nearly
three times that of Comparison Fabrics A and B.
[0037] Notably, the above-described high strength and abrasion
resistance is achievable with a fabric that is significantly
cheaper to produce than many high-end fabrics, such as Comparison
Fabric B, which comprises relatively costly PBI fiber. Therefore, a
high-strength, abrasion-resistant, and flame resistant fabric can
be produced at a relatively low cost.
[0038] While particular embodiments of fabrics have been disclosed
in detail in the foregoing description and drawings for purposes of
example, it will be understood by those skilled in the art that
variations and modifications thereof can be made without departing
from the scope of the disclosure.
* * * * *