U.S. patent application number 13/781062 was filed with the patent office on 2014-08-28 for reversible camouflage material.
This patent application is currently assigned to W. L. Gore & Associates, Inc.. The applicant listed for this patent is W. L. GORE & ASSOCIATES, INC.. Invention is credited to Matthew J. Castille.
Application Number | 20140242355 13/781062 |
Document ID | / |
Family ID | 51388444 |
Filed Date | 2014-08-28 |
United States Patent
Application |
20140242355 |
Kind Code |
A1 |
Castille; Matthew J. |
August 28, 2014 |
Reversible Camouflage Material
Abstract
A reversible camouflage material including a textile layer
having a woodland camouflage print thereon, an infrared suppressing
layer, and a textile layer having a desert camouflage print thereon
is provided. The infrared suppressing layer may include a
polyurethane layer sandwiched between a carbon-containing ePTFE
layer and an ePTFE layer. The carbon may be provided in an
oleophobic layer on the ePTFE or within the ePTFE film. In one
embodiment, the desert camouflage textile is absent and a coating
composition that includes a colorant and infrared suppressive
additives is applied to the outer surface of the ePTFE layer. The
inventive camouflage material demonstrates camouflage concealment
in the near IR (nIR) and short wave infrared (SWIR) wavelengths of
the electromagnetic spectrum. In addition, the camouflage material
is highly breathable and lightweight. The material is particularly
suitable for making reversible camouflage garments such as jackets
and pants.
Inventors: |
Castille; Matthew J.;
(Charlottesville, VA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
W. L. GORE & ASSOCIATES, INC. |
Newark |
DE |
US |
|
|
Assignee: |
W. L. Gore & Associates,
Inc.
Newark
DE
|
Family ID: |
51388444 |
Appl. No.: |
13/781062 |
Filed: |
February 28, 2013 |
Current U.S.
Class: |
428/196 ;
359/350; 359/359; 428/212; 428/315.9 |
Current CPC
Class: |
Y10T 428/24942 20150115;
B32B 2307/30 20130101; B32B 27/322 20130101; B32B 2437/00 20130101;
G02B 1/18 20150115; B32B 3/26 20130101; B32B 2571/00 20130101; B32B
2307/40 20130101; B32B 7/12 20130101; B32B 27/12 20130101; B32B
2255/26 20130101; B32B 7/02 20130101; B32B 2307/724 20130101; B32B
7/14 20130101; B32B 3/10 20130101; B32B 2264/0257 20130101; B32B
2307/7265 20130101; G02B 1/04 20130101; G02B 5/208 20130101; B32B
5/16 20130101; F41H 3/02 20130101; Y10T 428/24998 20150401; B32B
5/024 20130101; Y10T 428/2481 20150115; B32B 27/40 20130101; B32B
2255/02 20130101 |
Class at
Publication: |
428/196 ;
428/212; 428/315.9; 359/359; 359/350 |
International
Class: |
F41H 3/02 20060101
F41H003/02; B32B 3/10 20060101 B32B003/10; G02B 5/20 20060101
G02B005/20; B32B 7/12 20060101 B32B007/12; B32B 7/14 20060101
B32B007/14; B32B 7/02 20060101 B32B007/02; B32B 3/26 20060101
B32B003/26 |
Claims
1. A reversible article having a first surface and a second
surface, said reversible article comprising: (a) a center structure
comprising a polyurethane layer sandwiched between a first
microporous film and a second microporous film having thereon an
oleophobic layer containing at least one infrared suppressive
additive; (b) a first textile layer positioned on said first
microporous film; and (c) a second textile layer positioned on said
second microporous film such that said oleophobic layer is
positioned adjacent said second textile layer, wherein infrared
suppressive performance in said first surface and said second
surface is different.
2. The reversible article of claim 1, wherein said first and second
microporous films comprise expanded polytetrafluoroethylene.
3. The reversible article of claim 1, further comprising a first
adhesive layer bonding said first textile layer to said first
microporous film and a second adhesive layer bonding said second
textile layer to said second microporous film.
4. The reversible article of claim 1, wherein said oleophobic layer
is a fluoroacrylate oleophobic coating and said at least one
infrared suppressive additive is carbon.
5. The reversible article of claim 1, wherein said at least one
infrared suppressive additive is selected from carbon, aluminum,
aluminum oxide, antimony, antimony oxide, titanium, titanium oxide,
cadmium selinide, gallium arsenide and mixtures thereof.
6. The reversible article of claim 1, wherein said at least one
infrared suppressive additive is present in said oleophobic layer
in an amount from about 1% to about 15% by weight.
7. The reversible article of claim 1, wherein each of said first
and second surface of said reversible article demonstrates an
average reflection of about 75% or less in the wavelength range
from about 700 nm to about 900 nm and an average reflection from
about 10% to about 85% in the wavelength range from about 900 nm to
about 1700 nm.
8. The reversible article of claim 1, wherein each of said first
and second surface of said reversible article demonstrates an
average reflection less than about 65% or less in the wavelength
range from about 700 nm to about 900 nm and an average reflection
less than about 75% in the wavelength range from about 900 nm to
about 1700 nm.
9. The reversible article of claim 1, wherein said oleophobic layer
contains differing levels of said at least one infrared suppressive
additive to create a disruptive pattern in both the 700 nm to 900
nm and 900 nm to 1700 nm regions of the electromagnetic
spectrum.
10. The reversible article of claim 1, wherein each of said first
and second surface of said reversible article has a moisture vapor
transmission rate of at least about 8000 g/m.sup.2/24 hours, and
wherein said moisture vapor transmission rates of said first and
said second surface are substantially the same.
11. The reversible article of claim 1, wherein said reversible
article has a mass/area less than about 300 g/m.sup.2.
12. The reversible article of claim 1, wherein said first textile
has thereon a woodland camouflage printed surface and said second
textile has thereon a desert camouflage printed surface.
13. The reversible article of claim 1, wherein said article is a
garment.
14. The reversible article of claim 1, wherein said article is a
tent or bivy bag.
15. A reversible article having a first surface and a second
surface, said reversible article comprising: (a) a center structure
comprising a polyurethane layer sandwiched between a first
microporous film and a second microporous film having thereon an
oleophobic layer, said second microporous film containing at least
one infrared suppressive additive within said second microporous
film; (b) a first textile layer positioned on said first
microporous film; and (c) a second textile layer positioned on said
second microporous film such that said oleophobic layer is
positioned adjacent said second textile layer.
16. The reversible article of claim 15, wherein said first and
second microporous films comprise expanded
polytetrafluoroethylene.
17. The reversible article of claim 15, further comprising a first
adhesive layer bonding said first textile layer to said first
microporous film and a second adhesive layer bonding said second
textile layer to said second microporous film.
18. The reversible article of claim 15, wherein each of said first
and second surface of said reversible article demonstrates an
average reflection of about 75% or less in the wavelength range
from about 700 nm to about 900 nm and an average reflection from
about 10% to about 85% in the wavelength range from about 900 nm to
about 1700 nm.
19. The reversible article of claim 15, wherein said oleophobic
layer contains differing levels of said at least one infrared
suppressive additive to create a disruptive pattern in both the 700
nm to 900 nm and 900 nm to 1700 nm regions of the electromagnetic
spectrum.
20. The reversible article of claim 15, wherein said oleophobic
layer is a fluoroacrylate oleophobic coating and said at least one
infrared suppressive additive is carbon.
21. The reversible article of claim 15, wherein each of said first
and second surface of said reversible article has a moisture vapor
transmission rate of at least about 8000 g/m.sup.2/24 hours, and
wherein said moisture vapor transmission rate of said first and
said second surface is substantially the same.
22. The reversible article of claim 15, wherein said reversible
article has a mass/area less than about 300 g/m.sup.2.
23. The reversible article of claim 15, wherein said article is a
garment.
24. The reversible article of claim 15, wherein said article is a
tent or bivy bag.
25. A reversible article having a first surface and a second
surface, said reversible article comprising: (a) a center structure
comprising: a first microporous film; and a second microporous film
having thereon an oleophobic coating containing at least one
infrared suppressive additive, said second microporous film being
bonded to said first microporous film; (b) a first textile layer
positioned on said first microporous film; and (c) a second textile
layer positioned on said second microporous film such that said
oleophobic coating is positioned adjacent said second textile
layer, wherein infrared suppressive performance in said first
surface and said second surface is different.
26. The reversible garment of claim 25, wherein said first
microporous film and said second microporous film are bonded via an
adhesive layer.
27. The reversible article of claim 26, wherein said adhesive layer
is discontinuous.
28. The reversible article of claim 26, wherein said adhesive layer
is continuous.
29. The reversible article of claim 25, wherein said first
microporous film and said second microporous film form said center
structure in the absence of an adhesive.
30. The reversible article of claim 25, wherein said first
microporous film has thereon a coating containing at least one
infrared suppressive additive.
31. The reversible article of claim 30, wherein a first amount of
said infrared additive present on said first microporous film is
different from a second amount of said infrared additive on said
second microporous film.
32. The reversible article of claim 25, wherein said first and
second microporous films comprise expanded
polytetrafluoroethylene.
33. The reversible article of claim 25, further comprising a first
adhesive layer bonding said first textile layer to said first
microporous film and a second adhesive layer bonding said second
textile layer to said second microporous film.
34. The reversible article of claim 25, wherein said oleophobic
layer is a fluoroacrylate oleophobic coating and said at least one
infrared suppressive additive is carbon.
35. The reversible article of claim 25, wherein said oleophobic
layer contains differing levels of said at least one infrared
suppressive additive to create a disruptive pattern in both the 700
nm to 900 nm and 900 nm to 1700 nm regions of the electromagnetic
spectrum.
36. The reversible article of claim 52, wherein said first textile
has thereon a woodland camouflage printed surface and said second
textile has thereon a desert camouflage printed surface.
37. A reversible article having a first surface and a second
surface, said reversible article comprising: (a) a center structure
comprising: a first microporous film; and a second microporous film
having thereon an oleophobic layer, said second microporous film
containing at least one infrared suppressive additive within said
second microporous film; (b) a first textile layer positioned on
said first microporous film; and (c) a second textile layer
positioned on said second microporous film such that said
oleophobic layer is positioned adjacent said second textile layer,
wherein infrared suppressive performance in said first surface and
said second surface is different.
38. The reversible garment of claim 37, wherein said first
microporous film and said second microporous film are bonded via an
adhesive layer.
39. The reversible article of claim 38, wherein said adhesive layer
is discontinuous.
40. The reversible article of claim 38, wherein said adhesive layer
is continuous.
41. The reversible article of claim 37, wherein said first
microporous film and said second microporous film form said center
structure in the absence of an adhesive.
42. The reversible article of claim 37, wherein said first
microporous film contains at least one infrared suppressive
additive within said first microporous film.
43. The reversible article of claim 42, wherein a first amount of
said infrared additive present within said first microporous film
is different from a second amount of said infrared additive within
said second microporous film.
44. The reversible article of claim 37, wherein said first and
second microporous films comprise expanded
polytetrafluoroethylene.
45. The reversible article of claim 37, further comprising a first
adhesive layer bonding said first textile layer to said first
microporous film and a second adhesive layer bonding said second
textile layer to said second microporous film.
46. The reversible article of claim 37, wherein said oleophobic
layer contains differing levels of said at least one infrared
suppressive additive to create a disruptive pattern in both the 700
nm to 900 nm and 900 nm to 1700 nm regions of the electromagnetic
spectrum.
47. The reversible article of claim 37, wherein said oleophobic
layer is a fluoroacrylate oleophobic coating and said at least one
infrared suppressive additive is carbon.
48. A reversible article comprising: an infrared suppressing layer
comprising a layer of an adhesive sandwiched between a first
microporous film and a second microporous film having thereon a
coating composition containing at least one colorant and at least
one infrared suppressive additive, said second microporous film
forming a first outer surface; a textile layer positioned on said
first microporous film, said textile layer forming a second outer
surface; and an adhesive layer positioned between said textile
layer and said first microporous film.
49. The reversible article of claim 48, wherein said adhesive is
polyurethane.
50. The reversible article of claim 48, wherein said first and
second microporous films comprise expanded
polytetrafluoroethylene.
51. The reversible article of claim 48, wherein each of said first
and second outer surface of said reversible article demonstrates an
average reflection of about 75% or less in the wavelength range
from about 700 nm to about 900 nm and an average reflection from
about 10% to about 85% in the wavelength range from about 900 nm to
about 1700 nm.
52. The reversible article of claim 48, wherein said coating
composition contains differing levels of said at least one infrared
suppressive additive to create a disruptive pattern in both the 700
nm to about 900 nm and 900 nm to about 1700 nm regions of the
electromagnetic spectrum.
53. The reversible article of claim 48, wherein said second
microporous film further comprises an oleophobic layer.
54. The reversible article of claim 48, wherein said oleophobic
layer is a fluoroacrylate oleophobic coating and said at least one
infrared suppressive additive is carbon.
55. The reversible article of claim 48, wherein said reversible
article is a garment.
56. The reversible article of claim 48, wherein said reversible
article is a tent or bivy bag.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to camouflage
materials, and more specifically, to a reversible camouflage
material that demonstrates controlled reflectance in both the nIR
and SWIR regions of the electromagnetic radiation spectrum on both
sides of the garment while demonstrating high breathability on both
sides of the material.
BACKGROUND OF THE INVENTION
[0002] Camouflage textile materials used by hunters and by the
military typically provide camouflage in the visible region of the
electromagnetic radiation spectrum (400-700 nm). Due to the vastly
diverse environments throughout the world, many different
camouflage materials exist, including both visibly camouflaged and
non-visibly camouflaged materials. The variety of environments
(e.g., ranging from woodland to desert) necessitates the use of a
variety of colors and patterns to create these camouflage textile
materials. For instance, in a military woodland camouflage, the
materials often use four colors: black, coyote, khaki, and green.
In a military desert camouflage, the textile materials often use
four colors: highland, light coyote, urban tan, and light tan. Many
visible shade variations exist even within these two examples.
Textiles with visible camouflage patterns are typically
manufactured by printing the camouflage pattern on an undyed
(greige) textile (e.g., woven, knit, non-woven, etc.) surface or by
solution dying yarns that are subsequently woven or knitted into a
camouflage pattern using, for instance, a jacquard process.
[0003] In some applications it is desirable to use textile
materials that provide camouflage in other areas of the
electromagnetic spectrum (e.g., beyond visible). In particular,
advances in image intensifiers used in night vision equipment have
heightened the need for improved camouflage in the near infrared
("nIR") (i.e., 700-900 nm) and short wave infrared (SWIR) (i.e.,
900-1700 nm) electromagnetic radiation spectrum. Typical night
vision equipment amplifies low intensity electromagnetic radiation
in the visible, nIR, and SWIR spectra, with specific sensitivity in
the nIR and SWIR. Like camouflage in the visible spectrum,
camouflage in the nIR and SWIR spectra enables the material, and
thus the wearer or covered structure, to blend in with the
environment. A primary difference is that, unlike the visible
camouflage, nIR and SWIR camouflage does not involve a further
segmentation of discrete bands of the spectrum (that in the visible
gives rise to color separation). As such, effective camouflage in
the nIR and SWIR spectra requires a material to have an appropriate
balance of reflection, or reflectance, and transmittance/absorbance
over the whole nIR and SWIR spectra. In addition, the ability to
detect and identify an object using image intensifiers (such as
night vision goggles) also depends on the ability to disrupt the
silhouette or the shape of the object.
[0004] Conventional means for achieving desirable camouflage in
both the visible, nIR, and SWIR is through a printing process
wherein undyed textiles or textiles dyed to a base shade are
printed to simultaneously achieve multiple colors (visible
spectrum) and levels of nIR and SWIR reflectance. Most commonly,
carbon black is added to the camouflage print ink or paste in
varying amounts to vary the nIR and SWIR reflectance of the
resulting textile. A disadvantage to this technique is that the
carbon can negatively impact the desired visible shade of the
camouflage textile and frequently results in a compromise between
achieving appropriate visible and nIR camouflage, particularly in
environments which require extremely light shades like the desert.
In addition, topically treating textiles with such a carbon finish
results in a textile material with poor nIR camouflage durability,
as the topical carbon finishing can readily wash and/or wear off in
use.
[0005] A further challenge in creating camouflage textiles which
are suitable for the applications described is the need for comfort
of the user. In outdoor environments, comfort in a variety of
weather conditions requires that the textiles, and resulting
articles, be liquidproof and breathable for optimum comfort.
However, providing environmental protection by coating or
lamination of liquidproof, breathable films or coatings can also
affect the visible, nIR, and SWIR camouflage properties of the
textile. For example, in the specific case of a liquidproof,
breathable film comprising microporous PTFE, the PTFE film often
increases the overall reflectivity, in the nIR spectrum, and
possibly the visible spectrum as well, resulting in undesirable
tradeoffs between durable environmental protection and nIR and SWIR
camouflage.
[0006] Recent improvements to military camouflage have extended
performance into the nIR portion and the short wave infrared
(SWIR). Thus, there exists a need in the art for a camouflage
material that achieves camouflage protection in both the nIR and
SWIR spectra and that provides the desired physical and protection
properties needed and comfort qualities desired in a camouflage
garment.
SUMMARY OF THE INVENTION
[0007] It is an object of the present invention to provide a
reversible article that includes (1) a center structure including a
polyurethane layer sandwiched between a first microporous film and
a second microporous film having thereon an oleophobic layer
containing at least one infrared suppressive additive, (2) a first
textile layer positioned on the first microporous film, and (3) a
second textile layer positioned on the second microporous film. The
infrared suppressive performance on one surface of the reversible
article is different from the opposing surface of the reversible
article. The first textile layer is adhered to the first
microporous film and the second textile layer is adhered to the
second microporous film. The first and second microporous films may
be expanded polytetrafluoroethylene. In one exemplary embodiment,
the oleophobic layer is a fluoroacrylate oleophobic coating and the
infrared suppressive additive is carbon. The inventive camouflage
material demonstrates camouflage concealment in the near IR (nIR)
and short wave infrared (SWIR) wavelengths of the electromagnetic
spectrum on both sides of the material. In particular, both
surfaces of the reversible article demonstrate an average
reflection less than about 75% or less in the wavelength range from
about 700 nm to about 900 nm and an average reflection less than
about 85% in the wavelength range from about 900 nm to about 1700
nm.
[0008] It is another object of the present invention to provide a
reversible article that includes (1) a center structure including a
polyurethane layer sandwiched between a first microporous film and
a second microporous film having thereon an oleophobic layer, (2) a
first textile layer positioned on the first microporous film, and
(3) a second textile layer positioned on the second microporous
film. The second microporous film contains at least one infrared
suppressive additive within the microporous film. In exemplary
embodiments, the infrared suppressive additive is distributed
throughout the microporous film. A first adhesive layer bonds the
first textile layer to the first microporous film and a second
adhesive layer bonds the second textile layer to the second
microporous film. The infrared suppressive performance on one
surface of the reversible article is different from the opposing
surface of the reversible article. Additionally, the moisture vapor
transmission rates of the opposing surfaces of the reversible
article are substantially the same. In some exemplary embodiments,
the second microporous film is treated with differing levels of
infrared suppressive additives to create multiple regions of
reflection.
[0009] It is yet another object of the present invention to provide
a reversible article that includes (1) an infrared suppressing
layer including a polyurethane layer sandwiched between a first
microporous film and a second microporous film having thereon a
coating composition containing at least one colorant and at least
one infrared suppressive additive where the second microporous film
forms a first outer surface, (2) a textile layer positioned on the
first microporous film where the textile layer forms a second outer
surface, and (3) an adhesive layer positioned between the textile
layer and the first microporous film. The coating composition
includes a sufficient amount of colorant to colorize the second
microporous film and infrared suppressive additives to achieve nIR
and SWIR reflectance. The printed microporous film is colorized on
at least 90% of the outer film surface.
[0010] It is a further object of the present invention to provide a
reversible article that includes (1) a center structure including a
first microporous film bonded to a second microporous film having
thereon an oleophobic coating containing at least one infrared
suppressive additive, (2) a first textile layer positioned on the
first microporous film, and (3) a second textile layer positioned
on the second microporous film. The infrared suppressive
performance on one surface of the reversible article is different
from the opposing surface of the reversible article. The first and
second microporous films may be bonded together via a continuous or
a discontinuous adhesive. Alternatively, the first microporous film
and the second microporous film may form the center structure in
the absence of an adhesive. In one exemplary embodiment, the first
microporous film has thereon a coating that contains at least one
infrared suppressive additive. The first and second microporous
films may be expanded polytetrafluoroethylene.
[0011] It is a feature of the present invention that the two outer
surfaces of the reversible material have differing infrared
reflectivity.
[0012] It is also a feature of the present invention that the
reversible materials are highly breathable and lightweight.
[0013] It is a further feature of the present invention that both a
desert camouflage and a woodland camouflage are present in a
single, reversible article that demonstrates camouflage concealment
in the near nIR and SWIR wavelengths of the electromagnetic
spectrum on both sides of the article.
[0014] It is yet another feature of the present invention that the
nIR and SWIR reflectance can be tailored by altering the amount of
infrared suppressive additive present in the ePTFE layer.
BRIEF DESCRIPTIONS OF FIGURES
[0015] The advantages of this invention will be apparent upon
consideration of the following detailed disclosure of the
invention, especially when taken in conjunction with the
accompanying drawings wherein:
[0016] FIG. 1 is a schematic illustration of a reversible
camouflage material including a center structure that includes a
polyurethane layer sandwiched between a first microporous film and
a second microporous film and two outer facing textile materials
according to one exemplary embodiment of the invention;
[0017] FIG. 2 is a schematic illustration of a reversible
camouflage material including an infrared suppressing layer that
includes a polyurethane layer sandwiched between a first
microporous film and a second microporous film having thereon a
coating composition that contains at least one colorant and at
least one infrared suppressive additive according to another
exemplary embodiment of the invention;
[0018] FIG. 3 is a schematic illustration of a reversible
camouflage material including an infrared suppressing layer that
contains two ePTFE layers adhered via a discontinuous adhesive;
[0019] FIG. 4 is a schematic illustration of a reversible
camouflage material including an infrared suppressing layer that
contains two ePTFE layers adhered via a continuous adhesive;
and
[0020] FIG. 5 is a schematic illustration of a reversible
camouflage material including an infrared suppressing layer that
contains two ePTFE layers bonded without an adhesive.
DETAILED DESCRIPTION OF THE INVENTION
[0021] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which the invention belongs. Although
any methods and materials similar or equivalent to those described
herein can be used in the practice or testing of the present
invention, the preferred methods and materials are described
herein.
[0022] In the drawings, the thickness of the lines, layers, and
regions may be exaggerated for clarity. It will be understood that
when an element such as a layer, region, substrate, or panel is
referred to as being "on" another element, it can be directly on
the other element or intervening elements may also be present.
Also, when an element is referred to as being "adjacent" to another
element, the element may be directly adjacent to the other element
or intervening elements may be present. It is to be noted that like
numbers found throughout the figures denote like elements. As used
herein, "visible" refers to 400-700 nm, "nIR" refers to near
infrared 700-900 nm, and "SWIR" refers to 900-1700 nm in the
electromagnetic radiation spectrum. The terms "camouflage material"
and "material" may be used interchangeably herein.
[0023] The invention relates to a reversible camouflage material
that has a woodland camouflage print on one side of the material
and a desert camouflage print on the opposing side of the material.
The inventive camouflage material demonstrates camouflage
concealment in the near IR (nIR) and short wave infrared (SWIR)
wavelengths of the electromagnetic spectrum. In addition, the
camouflage material is both highly breathable and lightweight. The
material is particularly suitable for making reversible camouflage
garments such as jackets and pants.
[0024] Reference is first made to FIG. 1, which illustrates a
reversible camouflage material 10 according to at least one
embodiment of the present invention. The reversible material 10 is
a three-layer structure formed of a first textile layer 20 having a
woodland camouflage print thereon, an expanded
polytetrafluoroethylene (ePTFE) substrate 30 (infrared suppressing
layer), and a second textile layer 40 having a desert camouflage
print thereon. The ePTFE substrate contains a polyurethane layer 60
sandwiched between a carbon-containing ePTFE layer 50 and an ePTFE
layer 70. The carbon-containing ePTFE layer 50 may be coated with
carbon or the carbon may be positioned throughout the ePTFE layer.
The polyurethane layer 60 acts as an adhesive to bond the two ePTFE
layers 50, 70 together. ePTFE membranes having a thickness from
about 0.2 mil to about 5.0 mil may be utilized. In at least one
exemplary embodiment, the ePTFE membrane thickness is less than or
equal to 2.0 mil, or less than or equal to 1.0 mil. It is to be
noted that the infrared suppressive performance is different from
one side of the reversible material to the opposing side. The
phrase "infrared suppressive performance" as used herein is meant
to denote that the outer surfaces of the reversible camouflage
material have different nIR and SWIR reflective camouflage
performance. For example, one surface may be nIR and SWIR
reflective for a dry soil environment and the opposing surface may
be nIR and SWIR reflective for a foliage environment.
[0025] In alternate exemplary embodiments, the carbon-containing
ePTFE layer 50 and the ePTFE layer 70 are bonded by an adhesive,
such as is depicted in FIGS. 3 and 4. In particular, FIG. 3
illustrates a reversible material 150 that contains a center
structure 35 (infrared suppressing layer) where the
carbon-containing ePTFE layer 50 and the ePTFE layer 70 are bonded
by a discontinuous adhesive 85. A reversible material 160 where a
continuous adhesive 95 bonds the carbon-containing ePTFE layer 50
and the ePTFE layer 70 is depicted in FIG. 4. FIG. 5 depicts a
reversible material 170 where the carbon-containing ePTFE layer 50
and the ePTFE layer 70 are bonded together without an adhesive.
[0026] It is to be appreciated that reference is made herein with
respect to expanded polytetrafluorethylene (ePTFE) for ease of
discussion. However, it is to be understood that any suitable
expanded fluoropolymer membrane may be used interchangeably with
any ePTFE layer described within this application. Non-limiting
examples of expandable fluoropolymers include, but are not limited
to, expanded PTFE, expanded modified PTFE, expanded copolymers of
PTFE, fluorinated ethylene propylene (FEP), and perfluoroalkoxy
copolymer resin (PFA). Patents have been filed on expandable blends
of PTFE, expandable modified PTFE, and expanded copolymers of PTFE,
such as, but not limited to, U.S. Pat. No. 5,708,044 to Branca;
U.S. Pat. No. 6,541,589 to Baillie; U.S. Pat. No. 7,531,611 to
Sabol et al.; U.S. patent application Ser. No. 11/906,877 to Ford;
and U.S. patent application Ser. No. 12/410,050 to Xu et al. Porous
membranes including polymeric materials such as polyolefins (e.g.,
polypropylene and polyethylene), polyurethanes, polyesters,
polyamides, polyvinyls, polyvinyl chlorides, acrylics, silicones,
epoxies, synthetic rubbers, other thermoset polymers, and
copolymers of these types are considered to be within the purview
of the invention provided that the polymeric material can be
processed to form porous or microporous membrane structures.
[0027] One method of accomplishing nIR and SWIR reflectance within
the reversible material 10 is by coating or imbibing the carbon
into or on the film surface. Carbon is used herein for ease of
discussion. It is to be appreciated that any infrared suppressive
additive can be used in place of, or in addition to, the carbon. In
an embodiment where the ePTFE layer 50 is coated with a layer of
carbon, any conventional application method may be employed to
place a coating composition containing carbon onto the
carbon-coated ePTFE layer 50. Application methods for coating the
ePTFE layer 50 with carbon include but are not limited to, transfer
coating, screen printing, gravure printing, ink-jet printing, and
knife coating. Additional topical treatments can be applied to the
ePTFE layer 50, provided sufficient porosity throughout the ePTFE
substrate 30 is maintained to remain moisture vapor transmissivity.
For example, an oleophobic treatment, such as a fluoroacrylate
oleophobic coating, may be applied to the ePTFE layer 50. It is to
be appreciated that the oleophobic treatment may be applied in
conjunction with the application of carbon, or prior to or
subsequent to the application of the carbon coating.
[0028] Achieving the unique balance of visible and near infrared
electromagnetic characteristics, of the reversible material 10
requires a near infrared suppressive additive that can decrease the
nIR and SWIR reflectivity of the substrate 30 while maintaining a
light shade visible appearance. It is to be noted that a range of
additives suitable for decreasing the nIR and SWIR reflectivity are
available and can be used in place of, or in addition to, the
carbon described above. Non-limiting exemplary additives include
inorganic materials such as, but not limited to, metals, and metal
oxides, metal compounds, such as, but not limited to, aluminum,
aluminum oxide, antimony, antimony oxide, titanium, titanium oxide,
cadmium selinide, gallium arsenide, and the like, and organic
materials such as, but not limited to, conductive polymers and
those described in U.K. Patent Application No. GB 2,222,608A.
[0029] In an embodiment where the carbon (or other infrared
suppressive additive) is included within or substantially within
the ePTFE layer 50, the infrared suppressive material/additive(s)
that provide the nIR and SWIR suppression can either be soluble in
the polymeric matrix or exist as discrete particles. In either
instance, the infrared suppressive additives should be uniformly or
substantially uniformly dispersed in the polymeric matrix.
[0030] Infrared suppressive additive loadings onto and/or into the
carbon-containing ePTFE layer 50 can be varied depending on the
combination of properties desired. For example, carbon levels on
the order of about 1% by weight have been surprisingly found to be
effective in nIR and SWIR suppression while simultaneously
providing excellent shade retention in the articles. Infrared
suppressive additive(s) in an amount from about 1% to about at
least 15% by weight, or more, may be present in the
carbon-containing ePTFE layer. In the presence of other reflective
materials (e.g., TiO.sub.2 and the like) in the carbon-containing
ePTFE layer 50, higher loadings of carbon can be used to achieve
the desired balance of absorption and reflectance in the nIR, SWIR,
and visible spectra.
[0031] Conversely, at carbon levels on the order of 5% by weight
and higher, and even at levels down to 1% by weight, in the absence
of other reflective materials in the ePTFE layer 50, it has been
observed that the resulting membrane will appear black to the
unaided eye and would darken the shade of any light color textiles
to which it is attached. Resulting textile composites from these
carbon loading levels show significant and unacceptable darkening
of the light color visible camouflage to which it is adhered. This
light color shade shifting is particularly problematic in daylight
situations, which is also when visible camouflage with the correct
shades is most essential.
[0032] In some exemplary embodiments, the carbon-containing ePTFE
layer 50 is treated with differing levels of infrared suppressive
additives to create multiple regions of reflection (analogous to
camouflage printing of textiles). This allows for the incorporation
of a nIR/SWIR disruptive pattern into the film layer. The pattern
applied or achieved by the application of the infrared suppressive
additive could be altered in a variety of ways to achieve the
particular nIR and/or SWIR disruptive pattern desired. It is to be
appreciated that there are numerous ways to achieve multiple levels
of reflectance within the carbon-containing ePTFE layer, including,
but not limited to, using multiple types of infrared suppressive
additives, chemical modification, coating on an imbibed polymer
(e.g., a carbon-imbibed ePTFE layer 50), or combinations thereof.
It is also within the purview of the invention alter the nIR/SWIR
reflectance by physically altering the carbon-containing ePTFE
layer 50 such as by densifying or abrading select areas of the
ePTFE membrane.
[0033] It is important that the carbon-containing ePTFE layer 50
not exhibit too dark of a shade in the visible light spectrum. For
instance, if the nIR suppressive layer is too dark, it will alter
the shade of the desert camouflaged textile behind which it is
located.
[0034] Turning back to FIG. 1, the first and second textile layers
20, 40 are bonded to the ePTFE substrate 30 by adhesive layers 80,
90, respectively. In addition, the first textile layer 20 is
positioned adjacent to the ePTFE layer 70 and the second textile
layer 40 is positioned adjacent to the carbon-containing ePTFE
layer 50. Any suitable process for joining the ePTFE substrate 30
and the first and second textile layers 20, 40 may be used, such as
gravure lamination, fusion bonding, spray adhesive bonding, and the
like. The adhesive may be applied discontinuously or continuously,
provided that breathability through the camouflage material 10 is
maintained. For example, the adhesive may be applied in the form of
discontinuous attachments, such as by discrete dots, or in the form
of an adhesive web to adhere the first and second textile layers
20, 40 to the PTFE substrate 30 together.
[0035] The first and second textile layers 20, 40 may be formed of
a woven, knit, or non-woven material, and it may be comprised of
materials such as, but not limited to cotton, rayon, nylon,
polyester, and blends thereof. The weight of the textile forming
the first and second textile layers 20, 40 is not particularly
limited except as required by the application. In exemplary
embodiments, the textile is air permeable. As discussed above, the
textile layers 20, 40 are printed with a woodland camouflage
pattern and a desert camouflage pattern, respectively. The ink used
for printing the camouflage patterns contains nIR suppressive
materials such as carbon to aid in nIR and SWIR camouflage.
Application methods for printing the surface of the textile layers
20, 40 include but are not limited to, transfer coating, screen
printing, gravure printing, ink-jet printing, and knife
coating.
[0036] In another exemplary embodiment, the reversible material is
formed of a first textile layer 20 having a woodland camouflage
print thereon and an infrared suppressing layer 120. The infrared
suppressing 120 contains an adhesive layer 60 sandwiched between a
printed ePTFE layer 100 and an ePTFE layer 70. The adhesive layer
may be polyurethane. Such a reversible material 110 is shown in
FIG. 2. In this embodiment, a coating composition that includes a
colorant to colorize the ePTFE layer 100 and infrared suppressive
additives to achieve nIR and SWIR reflectance is applied to the
outer surface of the printed ePTFE layer 100.
[0037] In instances where the printed layer 100 is formed of ePTFE,
the coating composition coats or encapsulates the nodes and/or
fibrils of the expanded fluoropolymer structure forming a durable
aesthetic appearance. Aesthetic durability can be achieved in some
embodiments with colorant coating compositions that comprise a
pigment having a particle size sufficiently small to fit within the
pores of the porous substrate. Pigment particles having a mean
diameter of less than about 250 nm are useful for forming durable
color. Coating compositions may further comprise a binder capable
of wetting the porous substrate and binding the pigment to the pore
walls. Additional treatments may be provided to impart a desired
functionality to the ePTFE layer 100. As one non-limiting example,
oleophobic treatments may be applied to render the ePTFE layer 100
oleophobic.
[0038] Multiple colors can be applied using multiple pigments, or
varying the concentrations of one or more pigments, or by both
techniques. The printed ePTFE layer 100 is colorized on at least
90% of the outer film surface. Any of the conventional printing
techniques described herein may be utilized to print the outer
surface of the ePTFE layer 100 so long as the ePTFE substrate 120
maintains moisture vapor transmission. In one embodiment, the
surface of the film can be colorized with a colorant to form a
solid color or a pattern (design). Coating compositions comprising
colorants can be applied to provide a variety of colors and
designs, such as solid, camouflage, and various print patterns.
Additionally, the coating compositions may include one or more
colorants suitable for use in printing camouflage patterns, such as
woodland and desert patterns. In exemplary embodiments, the coating
composition including highland, light coyote, urban tan, and light
tan colorant suitable for printing a desert camouflage pattern.
Other compositions that include colorants shade variations are
considered within the purview of the invention.
[0039] Moisture vapor transmission, or breathability, is important
to provide cooling to a wearer of the outerwear apparel made from
reversible materials described herein. Fabric textiles described
herein are breathable and have a moisture vapor transmission rate
(MVTR) that is greater than about 4500 g/m.sup.2/24 hours, greater
than about 8000 g/m.sup.2/24 hours, greater than about 12000
g/m.sup.2/24 hours, or greater than about 16000 g/m.sup.2/24 hours
when tested according to the MVTR Test Method described herein.
Also, the moisture vapor transmission rate of the reversible
material is the surprisingly the same or substantially the same on
both sides for the embodiment depicted in FIG. 1 and described
herein. The reversible materials are also lightweight, and may have
a mass/area less than about 300 g/m.sup.2, less than about 200
g/m.sup.2, less than about 100 g/m.sup.2, or less than about 65
g/m.sup.2.
[0040] In order to achieve optimal results in a nIR application, it
is desirable to control the spectral response to create a
reversible article that has nIR and SWIR reflectance that is
neither too high nor too low. For example, a nIR and SWIR
reflectance that is too high relative to the surrounding
environment creates a bright silhouette under night vision.
Equally, a reflectance that is too low creates a dark silhouette
relative to the surrounding environment under night vision. For
articles with areas of different reflectance levels (i.e., nIR/SWIR
disruptive pattern), there will typically be areas that are very
nIR and/or SWIR suppressive and areas that are only moderately
reflective. It is to be understood that the optimum reflectance
levels varies with the environment.
[0041] The reversible materials described herein demonstrate nIR
and SWIR suppression of incident electromagnetic radiation in the
nIR and SWIR wavelength range on both sides of the material. Such
nIR and SWIR suppression is particularly useful because reduced
reflectivity in these wavelength ranges reduce the visibility of an
article when viewed in the dark with a night vision scope. The nIR
absorption characteristic of the reversible materials provide an
average reflection of about 75% or less in the wavelength range of
about 700 nm to about 900 nm. The nIR absorption characteristic may
be tailored to provide an average reflection of less than about
65%, less than about 55%, or less than about 45% in the wavelength
range of about 700 nm to about 900 nm.
[0042] The SWIR absorption characteristic of the reversible
materials provides an average reflection from about 10% to about
85% in the wavelength range of about 900 nm to about 1700 nm. In
exemplary embodiments, there are at least two, and desirably at
least three, reflectance levels within the range of about 10% to
about 85% to provide color separation and optimal blending with the
background. The nIR absorption characteristic may be tailored to
provide an average reflection of less than about 85%, less than
about 75%, or less than about 65% in the wavelength range of about
900 nm to about 1700 nm.
[0043] The level of reflectance preferred for any particular
environment is dependent on the reflectance of the background that
lies behind the article to be hidden by the reflective material.
For example, a background of trees and leaves is known in the art
to have a nIR reflectance between about 45% and 55% and a SWIR
reflectance between about 5% and 65%. Because an article of the
present invention can be tailored to have a reflectance that
closely matches that of a treed background (or other background),
the article will appear less visible when viewed in the dark
through a night vision instrument.
[0044] It is to be understood that one unique aspect of the
inventive reversible materials is that the infrared suppressive
additives are decoupled from the visible camouflage in the printed
surface so that the visible camouflage shades can be retained
within desired specifications while simultaneously providing the
necessary nIR and SWIR suppressive characteristics.
[0045] The reversible materials described herein are suitable for
use in various applications, including but not limited to forming
reversible garments (e.g. jackets, pants, ponchos, raincoats),
tents, covers, bivy bags, and the like. Advantageously, the
reversible material 10 exhibits high breathability on both sides of
the material. In addition, the reversible materials demonstrate
both nIR and SWIR reflectance on both sides of the garment to
enable the reversible material to blend into the background and
provide optimal camouflage.
Test Methods
[0046] It should be understood that although certain methods and
equipment are described below, any method or equipment determined
suitable by one of ordinary skill in the art may be alternatively
utilized.
Infrared (IR) Test Method
[0047] Spectral reflectance data shall be determined on both sides
of the fabric laminate and shall be obtained from 600 to 1700
nanometers (nm), for Woodland print, and 700 to 1700 nm, for Desert
print, at 20 nm intervals from 700 to 860 nm and at 100 nm
intervals from 900 to 1700 nm, on a spectrophotometer relative to
the barium sulfate standard, the preferred white standard. Other
white reference materials may be used provided they are calibrated
to absolute white, e.g. magnesium oxide or vitrolite tiles. The
spectral band width shall be less than 26 nm at 860 nm. Reflectance
measurements may be made by either the monochromatic or
polychromatic mode of operation. When the polychromatic mode is
used, the spectrophotometer shall operate with the specimen
diffusely illuminated with the full emission of a source that
simulates either CIE source A or CIE source D65. The specimen shall
be measured as a single layer, backed with six layers of the same
fabric and shade. Measurements shall be taken on a minimum of two
different areas and the data averaged. The measured areas should be
at least 6 inches away from the selvage. The specimen shall be
viewed at an angle no greater than 10 degrees from the normal, with
the specular component included. Photometric accuracy of the
spectrophotometer shall be within 1 percent and wavelength accuracy
within 2 nm. The standard aperture size used in the color
measurement device shall be 0.3725 inches in diameter. Any color
having spectral reflectance values falling outside the limits in
four or more of the wavelengths, in the 700-860 nm range, specified
shall be considered a test failure (as per MIL-PRF-32142 and MC/PD
11-2011 SYSCOM A).
Durability Test Method (Laundering)
[0048] Place 2.0+0.2 pounds of the cloth, and if needed, ballast in
an automatic washing machine set on permanent press cycle, high
water level and warm (100+10.degree. F.-0.degree. F.) wash
temperature. Place 0.5 ounce (14 grams) of 1993 AATCC Standard
Reference Detergent (non-phosphate) without optical brighteners
into the washer. The duration of each laundering cycle shall be
30+5 minutes. After laundering, place sample and ballast in an
automatic tumble dryer set on permanent press cycle,
150-160.degree. F. and dry for approximately fifteen to thirty
(15-30) minutes or until dry. The laundering equipment, washer and
dryer, shall be in accordance with AATCC No. 135.
Moisture Vapor Transmission Rate Test (MVTR)
[0049] The MVTR for each sample was determined in accordance with
the general teachings of ISO 15496 except that the sample water
vapor transmission (WVP) was converted into MVTR moisture vapor
transmission rate (MVTR) based on the apparatus water vapor
transmission (WVPapp) and using the following conversion.
MVTR=(Delta P value*24)/((1/WVP)+(1+WVPapp value))
[0050] To ensure comparable results, the specimens were conditioned
at 73.4.+-.0.4.degree. F. and 50.+-.2% rH for 2 hrs prior to
testing and the bath water was a constant 73.4.degree.
F..+-.0.4.degree. F.
[0051] The MVTR for each sample was measured once, and the results
are reported as g/m.sup.2-24 hours.
EXAMPLES
Example 1
[0052] A reversible garment material was constructed in the
following manner. A 30 denier (30D) by 30 denier (30D) printed,
woven woodland MARPAT camouflage fabric with carbon incorporated
into the ink used in the printing process is bonded as follows:
[0053] 1) A three-layer film composite, approximately 0.27 mm thick
was obtained consisting of a polyurethane layer sandwiched between
two ePTFE layers. This laminate was constructed in accordance with
the general teachings of U.S. Pat No. 5,418,054 to Sun except that
no phosphorous or other flame-retardant material was incorporated
into the polyurethane layer. A fluoroacrylate, carbon-containing
coating (to aid in controlling nIR reflectance), as generally
taught in U.S. Patent Publication No. 2007/0009679 to Holcombe, et
al. was then applied to one side of the film laminate in order to
render it oleophobic while preserving the microporous
structure.
[0054] 2) The bond of the woodland MARPAT fabric layer to the 3
layer film composite was made by applying a dot pattern of a melted
polyurethane adhesive to the non-coated side of the 3 layer film
composite. While the polyurethane adhesive dots were molten, the
fabric was positioned, non-printed side down, on top of the
adhesive side of the three layer film composite. This construct was
allowed to cool.
[0055] 3) The resulting bonded construct, with the coated side of
the film composite facing down, was then positioned on top of a 30D
by 30D desert MARPAT camouflage woven fabric. Carbon was
incorporated into the ink of the darker colors used in the printing
process. The bonded construct and the desert camouflage fabric were
subsequently bonded together by applying a dot pattern of a melted
polyurethane adhesive to the coated side of the 3 layer composite
film. While the polyurethane adhesive dots were molten, the fabric
was positioned, non-printed side down, on top of the adhesive side
of the three layer film composite. This construct was allowed to
cool.
[0056] 4) After the moisture curing adhesive has set, both sides of
the reversible garment material were treated with a waterproofing
agent.
[0057] Both initially and after 20 launderings, the construct met
the spectral nIR reflectance specifications as set forth below in
MIL-PRF-32142 (for Woodland print) and MC/PD 11-2011 SYSCOM A (for
Desert print). Also, the construct demonstrated SWIR reflectance
that closely matched the encountered background (dry soil and
foliage), indicating that the reversible construct was effective in
camouflaging the construct.
[0058] A seam tape was made in the following manner. A 30D by 30D
desert MARPAT camouflage woven fabric was obtained. Carbon was
incorporated into the ink of the darker, colors used in the
printing process. The camouflage fabric was bonded in a similar
fashion as the described previously to the fluoroacrylate,
carbon-containing side of a bicomponent ePTFE/PU film (to aid in
controlling nIR and SWIR reflectance), as generally taught in U.S.
Patent Publication No. 2007/0009679, and then the film side of this
structure was subsequently completely coated with'polyurethane.
Example 2
[0059] A reversible garment material was constructed in the
following manner. A 30D by 30D printed, woven woodland MARPAT
camouflage fabric with carbon incorporated into the ink used in the
printing process is bonded as follows:
[0060] 1) A three-layer film composite, approximately 0.17 mm thick
was obtained consisting of a polyurethane layer sandwiched between
two ePTFE layers. This laminate was constructed in accordance with
the general teachings of U.S. Pat. No. 5,418,054 to Sun except that
no phosphorous or other flame-retardant material was incorporated
into the polyurethane layer.
[0061] 2) The bond of the woodland MARPAT fabric layer to the 3
layer film composite was made by applying a dot pattern of a melted
polyurethane adhesive to the 3 layer film composite. While the
polyurethane adhesive dots were molten, the fabric was positioned,
non-printed side down, on top of the adhesive side of the three
layer film composite. This construct was allowed to cool.
[0062] The construct demonstrated nIR and SWIR reflectance that
closely matched the encountered background (dry soil and foliage),
indicating that the reversible construct was effective in
camouflaging the construct.
[0063] The invention of this application has been described above
both generically and with regard to specific embodiments. Although
the invention has been set forth in what is believed to be the
preferred embodiments, a wide variety of alternatives known to
those of skill in the art can be selected within the generic
disclosure. The invention is not otherwise limited, except for the
recitation of the claims set forth below.
* * * * *