U.S. patent application number 15/178689 was filed with the patent office on 2017-03-02 for parachute buffer material.
The applicant listed for this patent is CTW Development LLC. Invention is credited to Roger J. Crossfield, Thomas W. THEYSON, John T. Wilson.
Application Number | 20170058437 15/178689 |
Document ID | / |
Family ID | 58097625 |
Filed Date | 2017-03-02 |
United States Patent
Application |
20170058437 |
Kind Code |
A1 |
THEYSON; Thomas W. ; et
al. |
March 2, 2017 |
PARACHUTE BUFFER MATERIAL
Abstract
In one aspect, parachute buffer materials are described herein.
In some embodiments, parachute buffer materials described herein
comprise a fabric formed from a plurality of fibers and a coating
disposed on at least one outer surface of the fabric. The fibers
have an inner component formed from a thermoplastic material and an
outer component formed from a non-thermoplastic material. In some
cases, the fabric is a woven fabric. Additionally, the coating can
comprise or contain a silicone along with, or without, other
functional components. Moreover, materials described herein can be
used to form various structures for parachute buffering
applications, and the coatings of materials described herein can
enhance the materials' buffering performance.
Inventors: |
THEYSON; Thomas W.;
(Matthews, NC) ; Crossfield; Roger J.; (Matthews,
NC) ; Wilson; John T.; (Charlotte, NC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CTW Development LLC |
Charlotte |
NC |
US |
|
|
Family ID: |
58097625 |
Appl. No.: |
15/178689 |
Filed: |
June 10, 2016 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
62174192 |
Jun 11, 2015 |
|
|
|
62277610 |
Jan 12, 2016 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
D10B 2321/02 20130101;
D03D 15/0027 20130101; D10B 2507/06 20130101; D06N 2201/042
20130101; D10B 2331/04 20130101; D06N 3/042 20130101; D06N 2209/103
20130101; D06N 3/128 20130101; D10B 2331/021 20130101; D06N
2209/121 20130101; D06N 2209/1671 20130101; D06N 3/14 20130101;
D10B 2201/02 20130101; D06N 3/0006 20130101; D06N 2201/02 20130101;
D02G 3/36 20130101; D06N 2201/0263 20130101; D10B 2331/02
20130101 |
International
Class: |
D03D 15/00 20060101
D03D015/00; D02G 3/36 20060101 D02G003/36; D06N 3/04 20060101
D06N003/04; D06N 3/00 20060101 D06N003/00; D06N 3/12 20060101
D06N003/12; D06N 3/14 20060101 D06N003/14; D03D 1/04 20060101
D03D001/04; D02G 3/04 20060101 D02G003/04 |
Goverment Interests
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] The invention was made under a contract with an agency of
the U.S. Government. The name of the U.S. Government agency and
Government contract number are: Department of the Army, Contract
number W911QY-12-P-0343. The Government has certain rights in the
invention.
Claims
1. A parachute buffer material comprising: a fabric formed from a
plurality of fibers, the fibers having an inner filament fiber
component formed from a thermoplastic material and an outer staple
fiber component formed from a non-thermoplastic material; and a
coating disposed on at least one outer surface of the fabric, the
coating comprising a silicone.
2. The parachute buffer material of claim 1, wherein the inner
component is formed from a material selected from the group
consisting of a nylon, a polyester, and a polyolefin.
3. The parachute buffer material of claim 1, wherein the outer
staple fiber component is formed from a material selected from the
group consisting of cotton, linen, rayon, acrylic, and an
aramid.
4. The parachute buffer material of claim 1, wherein the outer
component is formed from cotton.
5. The parachute buffer material of claim 1, wherein the inner
component is a monofilament thread.
6. The parachute buffer material of claim 1, wherein the inner
component comprises a plurality of monofilament threads.
7. The parachute buffer material of claim 1, wherein the outer
component is spun around the inner component.
8. The parachute buffer material of claim 1, wherein the inner
filament fiber component forms between about 10 wt.-% and about 70
wt.-% of the total weight of the fibers.
9. The parachute buffer material of claim 1, wherein the inner
filament fiber component forms between about 30 wt.-% and about 50
wt.-% of the total weight of the fibers.
10. The parachute buffer material of claim 1, wherein the outer
staple fiber component forms between about 20 wt.-% and about 80
wt.-% of the total weight of the fibers.
11. The parachute buffer material of claim 1, wherein the outer
staple fiber component forms between about 40 wt.-% and about 70
wt.-% of the total weight of the fibers.
12. The parachute buffer material of claim 1, wherein the fabric is
woven.
13. The parachute buffer material of claim 12, wherein the fabric
is plain woven.
14. The parachute buffer material of claim 1, wherein the coating
further comprises a silicone polymer.
15. The parachute buffer material of claim 1, wherein the coating
further comprises a wax or blend of waxes.
16. The parachute buffer material of claim 1, wherein the coating
further comprises an acrylic polymer and/or a polyurethane
polymer.
17. The parachute buffer material of claim 1, wherein the coating
further comprises an anti-wicking agent.
18. The parachute buffer material of claim 1, wherein the coating
further comprises an antimicrobial agent.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority pursuant to 35 U.S.C.
.sctn.119(e) to U.S. Provisional Patent Application Ser. No.
62/174,192, filed on Jun. 11, 2015, and to U.S. Provisional Patent
Application Ser. No. 62/277,610, filed on Jan. 12, 2016, each of
which is hereby incorporated by reference in its entirety.
FIELD
[0003] The present invention relates to parachute buffer materials
and, in particular, to fabrics and/or surface treatments for such
materials.
BACKGROUND
[0004] In the development of the modern parachute, there have been
two major shifts. The first such shift came in the early 1940s,
when the United States ceased using silk and instead began to make
parachutes from nylon. The second major shift came in the 1950s,
when parachutes began to be used as a mechanism for the delivery of
larger, heavier materials dropped from airplanes traveling at much
higher speeds. It was discovered during the second major shift that
if a nylon parachute canopy contacted another nylon surface, such
as the outer nylon parachute bag, the resulting high speeds at the
contact interface caused melt damage to the parachute canopy. In
order to address this issue, "buffering" materials were developed
that were used to construct "buffer" structures designed to provide
protective surfaces between the nylon parachute canopy and other
nylons surfaces during the deployment process. These structures
included the primary buffering structure (the "parachute deployment
bag" or "parachute buffer bag") along with various other cords and
small fabric structures. All of these structures were designed to
minimize the potential for damaging nylon-on-nylon contact during
the deployment process. The original parachute buffer structures
were based on cotton. Such cotton-based structures (cotton
parachute buffer bags, cotton cords, and related structures)
provide the required separation of nylon surfaces, eliminating
contact damage during the parachute deployment process.
[0005] Since the shift to the use of buffer bags and related buffer
structures in the 1950s, the fabrics used to produce buffer bags
and other fabric structures have been formed from a cotton
"airplane cloth," originally designed to cover the wings and other
surfaces of airplanes. In order to obtain the desired properties
for use in buffer structures, airplane cloth has traditionally been
made or formed from 100% long staple cotton fibers. Unfortunately,
such material suffers from several disadvantages or deficiencies.
For example, obtaining and processing the high quality, long staple
cotton necessary to provide the high strength cotton fabric is
often difficult. Therefore, lower strength cotton fabrics have been
substituted for the higher strength cotton fabrics, resulting in
buffer bags with a reduced service life. Further, bags formed from
100% cotton fabric are often unusable after as little as one
washing cycle due to the shrinkage-prone nature of the fabric.
Thus, there is a need for improved buffer fabric/material that can
be used in the preparation of parachute buffer bags and related
buffer fabric structures. One objective of the present disclosure
is to provide a new parachute buffer material that addresses one or
more deficiencies of previous buffer materials.
SUMMARY
[0006] In one aspect, parachute buffer materials are described
herein which, in some embodiments, can provide one or more
advantages compared to other parachute buffer materials. For
instance, in some cases, a parachute buffer material or fabric
described herein can provide increased tear strength and/or
increased ball burst strength as compared to prior parachute buffer
materials or fabrics. In addition, in some instances, a parachute
buffer material or fabric described herein can provide increased
shrinkage resistance and/or increased air permeability as compared
to prior parachute buffer materials or fabrics. Further, parachute
buffer materials or fabrics described herein may also provide a
lower cost to produce and/or may be formed from less expensive
materials relative to prior parachute buffer materials or fabrics.
Parachute buffer materials or fabrics described herein may also
have a longer useful service life, including after multiple washing
cycles.
[0007] In some instances, a parachute buffer material described
herein comprises a fabric formed from a plurality of fibers and a
coating disposed on at least one outer surface of the fabric. The
fibers have an inner component formed from a thermoplastic material
and an outer component formed from a non-thermoplastic material,
and the coating comprises silicone. In some embodiments, the inner
component of the fibers is formed from a material selected from the
group consisting of a nylon, a polyester, a polypropylene, and a
polyethylene. Further, in some cases, the outer component of the
fibers is formed from a material selected from the group consisting
of cotton, linen, rayon, acrylic, and an aramid. In some instances,
each of the fibers comprises between about 10 wt.-% and about 70
wt.-% inner component, based on the total weight of the fiber.
Additionally, in some embodiments, each of the fibers comprises
between about 20 wt.-% and about 80 wt.-% outer component, based on
the total weight of the fiber. The fabric, in some cases, can be
woven. For example, in some embodiments, the fabric is a woven
fabric formed using a plain weave. Additionally, in certain
instances, the coating can further comprise or include additional
materials or components, such as a polymeric material, an
anti-wicking agent, and/or an antimicrobial agent.
[0008] These and other embodiments are described in more detail in
the detailed description which follows.
BRIEF DESCRIPTION OF THE FIGURES
[0009] FIGS. 1A and 1B illustrate an apparatus suitable for testing
fabrics usable in parachute buffer materials described herein.
DETAILED DESCRIPTION
[0010] Embodiments described herein can be understood more readily
by reference to the following detailed description, examples, and
drawings. Elements, apparatus, and methods described herein,
however, are not limited to the specific embodiments presented in
the detailed description, examples, and drawings. It should be
recognized that these embodiments are merely illustrative of the
principles of the present invention. Numerous modifications and
adaptations will be readily apparent to those of skill in the art
without departing from the spirit and scope of the invention.
[0011] In addition, all ranges disclosed herein are to be
understood to encompass any and all subranges subsumed therein. For
example, a stated range of "1.0 to 10.0" should be considered to
include any and all subranges beginning with a minimum value of 1.0
or more and ending with a maximum value of 10.0 or less, e.g., 1.0
to 5.3, or 4.7 to 10.0, or 3.6 to 7.9.
[0012] All ranges disclosed herein are also to be considered to
include the end points of the range, unless expressly stated
otherwise. For example, a range of "between 5 and 10" should
generally be considered to include the end points 5 and 10.
[0013] In one aspect, parachute buffer materials are described
herein. Parachute buffer materials can be used to form part or all
of any structure consistent with the objectives of the present
invention. For example, in some embodiments, parachute buffer
materials described herein can form part or all of a parachute
buffer bag. Parachute buffer materials described herein may also be
used to form part or all of a cord or other small fabric structure
used as a parachute buffer material. In some instances, a parachute
buffer material comprises a fabric formed from a plurality of
fibers, the fibers having an inner component formed from a
thermoplastic material and an outer component formed from a
non-thermoplastic material. A "thermoplastic material," for
reference purposes herein, is a plastic material, such as a
polymer, that becomes pliable or moldable above a specific
temperature and solidifies upon cooling. For example, a
thermoplastic material can be selected from the group consisting of
a polyamide, a polyester, or a polyolefin. In some cases, an inner
component can comprise, consist or consist essentially of nylon
6,6, nylon 6, polyethylene terephthalate ("PET"),
poly-1,3-propylene terephthalate ("PPT"), poly-1,4-butylene
terephthalate ("PBT") and/or combinations thereof. A
"non-thermoplastic material," for reference purposes herein, can be
any other naturally occurring or synthetic material that is not a
thermoplastic material. For example, in some embodiments, a
non-thermoplastic material can be selected from the group
consisting of cotton, linen, rayon, acrylic, and an aramid.
Examples of aramids usable as an outer component are KEVLAR.RTM.
and NOMEX.RTM. (commercially available from E. I. du Pont de
Nemours and Company).
[0014] The foregoing structure comprising an inner component
comprising or formed from a thermoplastic material, and an outer
component comprising or formed from a non-thermoplastic material
exemplifies a preferred embodiment of a fiber usable in fabrics for
parachute buffer materials described herein. However, other
structures are also contemplated. For example, in some embodiments,
fabrics can comprise or be formed from fibers comprising,
consisting, or consisting essentially of an inner component
comprising a non-thermoplastic material. Any non-thermoplastic
material can be used. For example, a non-thermoplastic material
usable as an inner component, in some embodiments, can be selected
from the group consisting of cotton, linen, rayon, acrylic, and an
aramid. In certain embodiments, a non-thermoplastic inner component
can be selected having relatively high tensile strength as compared
to other fiber materials.
[0015] Inner components and/or outer components of the fibers to be
used in the preparation of fabrics for use in the construction of
parachute buffer materials described herein can have any
architecture, orientation or configuration not inconsistent with
the objectives of the present invention. For example, in some
embodiments, the inner component is a monofilament thread. In
certain other embodiments, the inner component comprises or is
formed from a plurality of monofilament threads. In such
embodiments, one or more of the monofilament threads can be formed
from a first thermoplastic material and one or more of the
monofilament threads can be formed from a second thermoplastic
material differing from the first thermoplastic material. In other
cases, all or substantially all of the monofilament threads in such
a configuration can be formed from the same or substantially the
same thermoplastic material. Moreover, in some cases, the inner
component can be a bicomponent or conjugate fiber formed from a
plurality of thermoplastic materials.
[0016] The inner component of a fiber described herein can form any
proportion of the total weight of the fiber not inconsistent with
the objectives of the present invention. In some embodiments, for
instance, the fibers of a fabric described herein comprise between
about 10 wt.-% and about 70 wt.-% inner component, based on the
total weight of the fiber. In some cases, the fibers of a fabric
described herein comprise between about 10 wt.-% and about 60 wt.-%
inner component, or between about 10 wt.-% and about 50 wt.-% inner
component. In some embodiments, the fibers can comprise between
about 20 wt.-% and about 70 wt.-% inner component, between about 20
wt.-% and about 60 wt.-% inner component, or between about 30 wt.-%
and about 50 wt.-% inner component, based on the total weight of
the fiber.
[0017] The outer component of a fiber can be disposed around the
inner component of the fiber in any manner not inconsistent with
the objectives of the present invention. For example, in some
embodiments, the outer component can be spun around or wrapped
around a longitudinal axis of the inner component to form a core
spun yarn. For example, in one embodiment, a monofilament thread
formed from a thermoplastic material is used as a core, and one or
more threads or fibers of a non-thermoplastic material are wound,
spun or wrapped around the inner component to form an outer
component. In another embodiment, a monofilament thread formed from
a thermoplastic material is used as a core, and two or more threads
or fibers of a non-thermoplastic material are wound, spun or
wrapped around the inner component to form an outer component. In a
further embodiment, a plurality of monofilament fibers are used to
form a core portion and one or more staple fibers (short cut
fibers) of a non-thermoplastic material are wound, spun or wrapped
around the inner component to form an outer component.
[0018] An outer component described herein can form any proportion
of the total weight of a fiber not inconsistent with the objectives
of the present invention. In some embodiments, each of the fibers
can comprise between about 20 wt.-% and about 80 wt.-% outer
component, based on the total weight of the fiber. For example, in
some cases, the fibers can comprise between about 20 wt.-% and
about 70 wt.-% outer component, or between about 20 wt.-% and about
60 wt.-% outer component. In some instances, a fiber can comprise
between about 30 wt.-% and about 80 wt.-% outer component, between
about 40 wt.-% and about 80 wt.-% outer component, or between about
40 wt.-% and about 70 wt.-% outer component, based on the total
weight of the fiber. Additionally, individual spun fibers may be
plied to provide a stronger, more uniform fiber for weaving the
desired fabric.
[0019] A fabric formed from fibers consistent with the foregoing
description can have any structure or configuration not
inconsistent with the objectives of the present invention. For
example, in some embodiments, the fabric is woven. Any weaving
pattern not inconsistent with the objectives of the present
invention can be used. In some embodiments, the woven fabric is a
plain woven fabric formed using a plain weave. In certain other
cases, the woven fabric is formed using a satin weave or a twill
weave. In addition, in some cases, the fabric can have a weight
between about 3 oz./yd.sup.2 and about 5 oz./yd.sup.2, between
about 3.5 oz./yd.sup.2 and about 4.5 oz./yd.sup.2, between about 3
oz./yd.sup.2 and about 4 oz./yd.sup.2, or between about 4
oz./yd.sup.2 and about 5 oz./yd.sup.2. Further, in some
embodiments, the fabric can have a weight less than about 5
oz./yd.sup.2, such as less than about 4.5 oz./yd.sup.2. Further,
fabrics usable in parachute buffer materials described herein can
demonstrate a resistance to failure in a constant speed constant
weight Draped Mandrel Test consistent with the description provided
in the Examples provided hereinbelow.
[0020] In some embodiments, fabrics usable in parachute buffer
materials described herein are provided uncoated or substantially
uncoated. In such embodiments, fabrics described herein can provide
superior characteristics or traits, such as high-speed
fabric-on-fabric friction resistance. However, in certain preferred
embodiments, parachute buffer materials can further comprise a
coating disposed on at least one outer surface of the fabric. Such
coatings are, in some instances, applied to fabrics described
herein comprising fibers having an inner component formed from a
thermoplastic material and an outer component formed from a
non-thermoplastic material. In certain other cases, coatings
described herein may be applied to other fabrics having a differing
composition or structure. For example, in some embodiments,
coatings described herein can be applied to cotton, nylon,
polyester, cotton/polyester blended fabrics, or airplane cloth.
Thus, in another aspect, methods of coating a fabric are described
herein, the methods comprising coating a fabric with a coating or
coating composition described herein. As described further
hereinbelow, coating a variety of fabrics with a coating described
herein can improve various properties of the fabrics, including for
parachute buffer material applications.
[0021] Coatings for buffer fabrics or other parachute buffer
materials described herein can comprise or include one or more
components. In particular, a coating described herein can comprise
one or more of a silicone-containing component, a wax component, a
polymeric acrylic or urethane-containing component, and an
antimicrobial agent-containing component. Various combinations of
such components can also be used in a coating described herein.
[0022] In certain cases, the coating can comprise or a silicone or
a silicone-containing component. For example, in some embodiments,
a silicone-containing component of a coating comprises LUROL.RTM.
PS-11158 (commercially available from Goulston Technologies, Inc.,
Monroe, N.C.), LUROL.RTM. PS-662 (Goulston Technologies, Inc.),
XIAMETER.RTM. MEM-0008 Emulsion (commercially available from Dow
Corning Corporation, Midland, Mich.), XIAMETER.RTM. MEM-0037
Emulsion (Dow Corning), XIAMETER.RTM. MEM-0939 Emulsion (Dow
Corning), and/or combinations thereof. Not intending to be bound by
theory, it is believed that disposing a coating comprising or
containing a silicone or silicone-containing component can provide
superior friction resistance relative to prior coatings. Further, a
coating disposed on a parachute buffer material described herein
can comprise one or more additional components or materials
intended to provide desirable characteristics to at least one outer
surface of the fabric.
[0023] In some embodiments, the coating further comprises a wax
material such as a material or composition comprising a wax or
mixture of waxes. For example, in some embodiments, the wax
component could be a polyethylene wax or a paraffin wax or a
vegetable wax or a combination of waxes. Such waxes can be applied
to the outer surface of the fabric, typically from emulsion during
the fabric finishing process or applied to the fiber as it is
produced by rubbing the fiber against a wax disk. Not intending to
be bound by theory, it is believed that some wax components or
materials, applied as coatings, can, in some embodiments, provide
enhanced fiber and/or fabric frictional properties.
[0024] In some embodiments, the coating further comprises a
polymeric material or polymeric component such as a composition or
material comprising an acrylic polymer or a polyurethane. For
example, in some embodiments, a polymeric component of a coating
comprises acrylic polymers such as those supplied by Dow Chemical
under the trade name Rhoplex or by Stan Chem Inc. under the
tradename StanChem or urethane polymers such as those supplied by
Bond Polymers under the trade name Bondthane or by Hauthaway under
the trade name Hauthane. Not intending to be bound by theory, it is
believed that some polymeric components or materials used in
coatings can, in some embodiments, provide enhanced fiber and/or
fabric structure stability.
[0025] Additionally, a coating can further comprise one or more
anti-wicking agents. An anti-wicking agent, in some embodiments,
can provide hydrophobicity to a fiber or fabric to reduce,
minimize, or eliminate absorption of moisture in the fiber or
fabric. In some embodiments, an anti-wicking agent of a coating
described herein can comprise a fluorochemical such as a
fluorinated polymer or fluorinated hydrocarbon. For example, in
some embodiments, a fluoro chemical component of a coating
comprises fluoro polymer such as those supplied by 3M corporation
under the trade name Scotch Guard or by Dakin under the trade name
Unidyme or fluoro polymers/extenders such as those supplied by
Clariant under the trade name Nuva.
[0026] Moreover, in some cases, a coating disposed on at least one
outer surface of the fabric can comprise or contain an
antimicrobial agent. An antimicrobial agent can be used in order to
reduce, minimize, or eliminate growth of organisms such as viruses,
fungi, or bacteria on or in the fabric. Any antimicrobial agent not
inconsistent with the objectives of the present invention may be
used. An antimicrobial agent, in some embodiments, comprises an
inorganic composition, including metals and/or metal salts. In some
embodiments, for example, an antimicrobial agent comprises metallic
copper, zinc, or silver or a salt of copper, zinc, or silver or
salts of these metallic elements. In other instances, an
antimicrobial agent comprises an organic composition, including
natural and synthetic organic compositions. In some cases, an
antimicrobial agent comprises a .beta.-lactam such as a penicillin
or cephalosporin. An antimicrobial agent may also comprise an
organic acid, such as lactic acid, acetic acid, or citric acid. In
some embodiments, an antimicrobial agent comprises a quarternary
ammonium species. A quarternary ammonium species, in some
embodiments, comprises a long alkyl chain, such as an alkyl chain
having a C8 to C28 backbone. In some cases, an antimicrobial agent
comprises one or more of benzalkonium chloride, benzethonium
chloride, methylbenzethonium chloride, cetalkonium chloride,
cetylpyridinium chloride, cetrimonium, cetrimide, dofanium
chloride, tetraethylammonium bromide, didecyldimethylammonium
chloride, and domiphen bromide. In some embodiments, the
antimicrobial agent may be a trialkoxy silane functionalized
quaternary based on a C12 to C18 alkyl chain. For example, in some
cases, an antimicrobial agent usable in a coating described herein
can be LUROL.RTM. Ag 1000 (commercially available from Goulston
Technologies, Inc.), MICROSILVER BG.RTM. (commercially available
from Bio-Gate AG, Nurnberg, Germany), AEGIS MICROBE SHIELD.RTM.
(commercially available from Microban International, Huntersville,
N.C.), BIOSHIELD.RTM. 75 (commercially available from IndusCo,
Ltd., Greensboro, N.C.), ZINC OMADINE.RTM. Enhanced CP Dispersion
(commercially available from Lonza Group Ltd., Basel, Switzerland),
and/or combinations thereof.
[0027] Some embodiments of parachute buffer materials described
herein and fabrics utilized for such buffer materials are further
illustrated in the following non-limiting examples.
Examples
Parachute Buffer Materials or Fabrics
[0028] A series of fabrics consistent with various embodiments of
parachute buffer materials described herein were prepared. A second
series of reference fabrics were also prepared or acquired for
comparative testing. A listing of the base fabric information for
each of the Reference and Test Fabrics is provided in Table 1.
Reference Fabric 1 and Test Fabric 1 were each formed from a plain
weave of nylon fibers. Reference Fabric 2 and Test Fabric 2 were
each formed from a plain weave of 100% polyester (PET) fibers.
Reference Fabric 3 and Test Fabric 3 were formed from a plain weave
comprising 35% cotton fibers and 65% PET fibers. Reference Fabric 4
and Test Fabric 4 were each formed from a plain weave of 100%
cotton fibers. Reference Fabric 6 was a conventional, plain weave,
cotton Airplane Cloth (APC). Test Fabric 5 and Test Fabric 6 were
each formed from a Hybrid Fabric. The Hybrid Fabric was prepared
from a core spun yarn prepared by spinning a long staple cotton
outer component around a core or inner component of high strength,
fully drawn polyester filament yarn. The core spun yarn was about
55 wt.-% polyester and about 45 wt.-% cotton, based on the total
weight of the yarn. The yarn was then plied to provide a 46/2 count
yarn used for weaving a fabric. The two ply, 46/2 core spun yarn
was woven into a plain weave fabric. The fabric was prepared with
62 warp ends per inch and 62 weft ends per inch. The fabric was
then scoured to remove any residual materials from the spinning and
weaving process.
[0029] Test Fabrics 1-5 were each treated with a coating
composition ("Coating 1"). Coating 1 comprised a
silicone-containing component (LUROL PS 662), polymeric component
(an acrylic polymer), and an antimicrobial agent (Aegis Microbial
Shield). The properties of Reference Fabric 6 and Test Fabric 6 are
provided below in Table 2.
TABLE-US-00001 TABLE 1 Compositional Information for Each Fabric
Fabric Base Fabric Coating Reference Fabric 1 Nylon None Reference
Fabric 2 Polyester (PET) None Reference Fabric 3 Cotton/PET (35/65)
None Reference Fabric 4 Cotton/PET (50/50) None Reference Fabric 5
Cotton None Reference Fabric 6 Airplane Cloth (APC) None Test
Fabric 1 Nylon Coating 1 Test Fabric 2 PET Coating 1 Test Fabric 3
Cotton/PET (35/65) Coating 1 Test Fabric 4 Cotton Coating 1 Test
Fabric 5 Hybrid Fabric Coating 1 Test Fabric 6 Hybrid Fabric
None
TABLE-US-00002 TABLE 2 Properties of Reference Fabric 6 and Test
Fabric 6 Warp Warp Fill Fabric Warp Fill Yarn Fill Yarn Tensile
Tensile Fabric Weight Count Count Density Density Strength Strength
Description (oz./yd.sup.2) (ends/in.) (ends/in.) (Denier) (Denier)
(lbf) (lbf) Reference 4.5 82 82 180 (est.) 180 (est.) 80 80 Fabric
6 Test Fabric 6 4.3 66 63 231 231 145.3 142.2
Test Design
Time to Break
[0030] In order to determine the time to break ("TTB"), an
edge-sealed strip of parachute fabric is brought into contact with
the surface of a fabric to be evaluated at a fixed high speed and
with a predetermined tension applied, the following method was
carried out.
Materials
Time to Break
[0031] The materials used for the test procedure were as follows:
double sided tape, parachute canopy fabric, 50 cm.times.3.0 cm
strips of a fabric to be tested, 100-500 g weights, a stopwatch,
and a Draped Mandrel Tester ("DMT"). The DMT was constructed from a
variable speed motor having a custom machined 6 inch aluminum wheel
with side restraints and equipped with a tensiometer. An example of
a DMT (100) usable in procedures carried out in the present example
is illustrated in FIGS. 1A and 1B.
Test Procedure
Time to Break
[0032] First, the parachute canopy fabric ("PCF") was cut into 1.25
cm.times.45 cm strips using a heat welder. A loop was created in
the PCF (102) by folding the ends of the PCF (102) over and
stapling the PCF (102) in place. The PCF (102) was then secured
onto the wheel (104) of the DMT (100) using the double sided tape
with an overlap of approximately 1 cm. Once the PCF (102) was
placed on the wheel (104), the PCF (102) was folded down on both
sides of the wheel (104) and fastened into position with the side
restraints (106a, 106b), which were bolted onto the DMT motor (not
shown). With the PCF (102) being fastened to the DMT (100), the
fabric to be tested (108) was first attached at one end to the
tensiometer (110). The fabric to be tested (108) was then draped
across the top of the DMT wheel (104) and tensioned using the
pre-tensioning weights (112). The cumulative angular contact of the
test specimen against the friction-inducing surface ("wrap angle")
was maintained at 90.degree.. Guide loops (114) were also used to
ensure that the fabric to be tested (108) was held in the
appropriate position in the middle section of the DMT wheel (104)
during the test.
[0033] For a constant speed variable weight test, a standard speed
can be selected that is appropriate to replicate parachute
deployment conditions. For the present example, a speed of 1800
meters per minute was selected which corresponds to a value near
the upper limit during parachute deployment. A constant pretension
weight between 100 g and 500 g for each trial of each fabric was
also used, and the test was stopped when the fabric to be tested
generated a break in the parachute canopy fabric, at which point
the TTB was measured, or until 90 seconds if the parachute canopy
fabric did not fail. Weight was increased by 50 g for each
subsequent trial, and the weight used for the highest weight pass
and lowest weight fail were recorded.
Results
Time to Break
[0034] The results of the Draped Mandrel Test for Reference Fabrics
1-6 and Test Fabrics 1-6 at a speed of 1800 meters per minute are
provided in Table 3 below. In Table 3 below, "Pass" refers to the
maximum pretension weight for which a Reference Fabric or Test
Fabric does not fail within 90 seconds. "Fail" refers to the
pretension weight at which the Reference Fabric or Test Fabric
fails along with the TTB in seconds.
TABLE-US-00003 TABLE 3 Comparative Test Results Fabric Pass Fail
Reference Fabric 1 50 g 100 g/9 s Reference Fabric 2 50 g 100 g/25
s Reference Fabric 3 200 g 250 g/13 s Reference Fabric 4 250 g 300
g/15 s Reference Fabric 5 350 g 400 g/60 s Reference Fabric 6 400 g
450 g/40 s Test Fabric 1 300 g 350 g/25 s Test Fabric 2 350 g 400
g/60 s Test Fabric 3 400 g 450 g/30 s Test Fabric 4 400 g 450 g/30
s Test Fabric 5 400 g 450 g/65 s Test Fabric 6 400 g 450 g/10 s
Results
Other Parameters
[0035] Selected Reference and Test Fabrics were comparatively
tested according to a number of additional test protocols. Namely,
Reference Fabric 5 and Test Fabrics 5 and 6 were compared.
Comparative data is provided in Table 4 below.
TABLE-US-00004 TABLE 4 Comparative Data Reference Test Method
Fabric 6 Test Fabric 5 Test Fabric 6 Ballburst ASTM B-6797- 74 lbf
231 lbf 214 lbf 07 Air ASTM D-2261 43 ft.sup.3/ft.sup.2 101
ft.sup.3/ft.sup.2 100 ft.sup.3/ft.sup.2 Permeability Opt 1
Flexibility 53 g 67 g 67 g Shrinkage AATTC 135 3 to 5% <1%
<1% Wicking 30 sec test 0.0 cm 0.0 cm 0.4 cm 5 min test 0.0 cm
0.0 cm 2.9 cm 10 min test 0.0 cm 0.0 cm 4.5 cm
[0036] Various embodiments of the invention have been described in
fulfillment of the various objectives of the invention. It should
be recognized that these embodiments are merely illustrative of the
principles of the present invention. Numerous modifications and
adaptations thereof will be readily apparent to those skilled in
the art without departing from the spirit and scope of the
invention.
* * * * *