U.S. patent application number 11/409113 was filed with the patent office on 2007-04-26 for fabric and a method of making the fabric.
Invention is credited to Ian Blanchonette, Ronald James Denning, David John Evans, Barry Victor Holcombe, Petra Kiessling, John Anthony Rippon, Birgit Schaldecker, Laurence Michael Staynes.
Application Number | 20070093162 11/409113 |
Document ID | / |
Family ID | 36202623 |
Filed Date | 2007-04-26 |
United States Patent
Application |
20070093162 |
Kind Code |
A1 |
Holcombe; Barry Victor ; et
al. |
April 26, 2007 |
Fabric and a method of making the fabric
Abstract
The present invention is based on the realization that improved
wicking of liquid from an inner face to an outer face of a fabric
can be achieved by a fabric structure where the inner face of the
fabric has a substantially uniform hydrophobicity and where the
inner face is formed by hydrophobic yarn that is assembled in a
manner that allows the liquid to penetrate between hydrophobic yarn
and make contact with hydrophilic yarn that forms at least part of
the outer face of the fabric. When liquid penetrates the inner face
and makes contact with the hydrophilic yarn, liquid is able to be
drawn through the inner face to the outer face of the fabric.
Although the hydrophobic and hydrophilic yarns and may be made from
any one or a blend of man-made or synthetic fibers, and natural
fibers, it is preferred that the yarns and the fully formed fabric
be made entirely of cotton fibers. The fabric is suitable for use
in a wide range of applications including underwear. Another
application involves laminating the fabric to a functional film
such as a waterproof and/or windproof breathable membrane to
produce functional outerwear garments.
Inventors: |
Holcombe; Barry Victor; (Dee
Why, AU) ; Blanchonette; Ian; (Jan Juc, AU) ;
Evans; David John; (West Melbourne, AU) ; Staynes;
Laurence Michael; (Flemington, AU) ; Rippon; John
Anthony; (Torquay, AU) ; Denning; Ronald James;
(Highton, AU) ; Schaldecker; Birgit;
(Feldkirchen-Westerham, DE) ; Kiessling; Petra;
(Brannenburg, DE) |
Correspondence
Address: |
GORE ENTERPRISE HOLDINGS, INC.
551 PAPER MILL ROAD
P. O. BOX 9206
NEWARK
DE
19714-9206
US
|
Family ID: |
36202623 |
Appl. No.: |
11/409113 |
Filed: |
April 21, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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PCT/AU05/01638 |
Oct 21, 2005 |
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11409113 |
Apr 21, 2006 |
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Current U.S.
Class: |
442/208 ;
139/418; 442/209; 442/211; 442/212; 442/312 |
Current CPC
Class: |
Y10T 442/3228 20150401;
D03D 15/00 20130101; D10B 2201/02 20130101; D10B 2201/20 20130101;
D10B 2401/022 20130101; D10B 2401/041 20130101; A41B 2400/60
20130101; D10B 2401/021 20130101; D10B 2331/04 20130101; D10B
2331/02 20130101; A41D 31/12 20190201; A61F 2013/51139 20130101;
D10B 2211/02 20130101; D06M 13/02 20130101; A61F 13/15577 20130101;
D10B 2403/0114 20130101; Y10T 442/3244 20150401; D04B 1/16
20130101; A61F 13/513 20130101; D10B 2321/10 20130101; Y10T 442/45
20150401; D10B 2321/041 20130101; Y10T 442/3252 20150401; D03D
11/00 20130101; D10B 2501/00 20130101; D10B 2331/10 20130101; A61F
2013/00238 20130101; D06M 15/643 20130101; A61F 13/51305 20130101;
D06M 15/277 20130101; Y02P 70/62 20151101; D02G 3/04 20130101; A41B
17/00 20130101; A61F 2013/51042 20130101; D06M 15/227 20130101;
Y10T 442/322 20150401; D10B 2321/022 20130101 |
Class at
Publication: |
442/208 ;
139/418; 442/209; 442/211; 442/212; 442/312 |
International
Class: |
D03D 23/00 20060101
D03D023/00; D03D 15/00 20060101 D03D015/00; D04B 1/22 20060101
D04B001/22 |
Claims
1. A fabric including: a) an inner face that is formed entirely
from one or more than one hydrophobic yarn that has been treated to
render it hydrophobic and said yarn or yarns are assembled over the
inner face so that the inner face has a hydrophobicity that is
substantially the same over the inner face; and b) an outer face
that in comparison to the inner face is hydrophilic and is formed
at least in part by one or more than one hydrophilic yarn, wherein
the hydrophobic yarn or yarns are assembled so that liquid can
penetrate the inner face and make contact with the hydrophilic yarn
or yarns that form at least part of the outer face of the fabric
and that, in turn, can draw liquid to the outer face of the
fabric.
2. The fabric according to claim 1, wherein the hydrophobic yarn or
yarns are assembled so that some sections of hydrophobic yarn in
the inner face are separated by spaces through which liquid can
penetrate.
3. The fabric according to claim 1, wherein hydrophobic yarn or
yarns are assembled over the inner face of the fabric so as to form
loops or floats on the inner face and thereby form said sections of
hydrophobic yarn separated by spaces.
4. The fabric according to claim 1, wherein the spacing of the
sections of hydrophobic yarn on the inner face of the fabric ranges
from 0.01 to 25 mm in the wale or warp direction and ranges from
0.01 to 25 mm in the course or weft direction.
5. The fabric according to claim 1, wherein the spacing of the
sections of hydrophobic yarn on the inner face of the fabric ranges
from 0.1 to 2.5 mm in the wale or warp direction and ranges from
0.1 to 2.5 mm in the course or weft direction.
6. The fabric according to claim 1, wherein when worn against skin
or located against an object, the hydrophobic yarn directly
contacts the skin or object without hydrophilic yarn directly
contacting the skin or object.
7. The fabric according to claim 1, wherein the hydrophilic and
hydrophobic yarns include any one or a blend of the following types
of fibers: a) man-made or synthetic fibers including, but not
restricted to, polyester, polyurethane, polypropylene, polyamide,
polyacrylonitrite, polyvinylchloride and regenerated cellulose; and
b) natural fibers including proteinaceous fibers such as wool and
hair and cellulosic fibers such as cotton.
8. The fabric according to claim 1, wherein the hydrophobic yarn or
yarns are pre-treated with a hydrophobic agent prior to formation
of the fabric.
9. The fabric according to claim 8, wherein fibers of the
hydrophobic yarn or yarns are pre-treated with a hydrophobic agent
when in the form of a yarn.
10. The fabric according to claim 1, wherein the outer face of the
fabric is made from at least 50 percent hydrophilic yarn.
11. The fabric according to claim 1, wherein the outer face of the
fabric is formed from at least 80 percent hydrophilic yarn.
12. The fabric according to claim 1, wherein the outer face of the
fabric is formed from 100 percent hydrophilic yarn.
13. The fabric according to claim 1, wherein the hydrophobic yarn
is pre-treated using an exhaust process.
14. The fabric according to claim 1, wherein at least one of the
hydrophobic or hydrophilic yarns include cotton fibers and/or other
types of cellulosic fibers.
15. The fabric according to claim 1, wherein at least one of the
hydrophobic or hydrophilic yarns contains at least 50 percent
cotton and/or other types of cellulosic fibers.
16. The fabric according to claim 1, wherein at least one of the
hydrophobic or hydrophilic yarns contain at least 80 percent cotton
and/or other types of cellulosic fibers.
17. The fabric according to claim 1, wherein both of said yarns are
made entirely of cotton and/or other types of cellulosic
fibers.
18. The fabric according to claim 1, wherein the ratio of
hydrophilic to hydrophobic yarns on a mass basis ranges from 95:5
to 10:90 respectively.
19. The fabric according to claim 1, wherein the ratio of
hydrophilic to hydrophobic yarns on a mass basis ranges from 60:40
to 80:20 respectively.
20. The fabric according to claim 1, wherein the hydrophobic and
hydrophilic yarns are intermeshed in a manner whereby the
hydrophilic yarns from part of a core or central region of the
fabric and the outer face of the fabric.
21. The fabric according to claim 1, wherein the hydrophobic yarn
is located at a distance ranging from 0.01 to 2.0 mm from an outer
plane of the inner face of the fabric.
22. The fabric according to claim 1, wherein the hydrophobic yarn
is located at a distance ranging from 0.1 to 1.0 mm from an outer
plane of the inner face of the fabric.
23. The fabric according to claim 1, wherein the fabric has a
buffering capacity against liquid water K.sub.f, which, when
measured in accordance with a Hohenstein Institute standard test,
ranges from 0.1 to 1.
24. The fabric according to claim 1, wherein the fabric has a
buffering capacity against liquid water K.sub.f, which, when
measured in accordance with a Hohenstein Institute standard test,
ranges from 0.9 to 1.
25. The fabric according to claim 1, wherein the fabric has a drop
sorption index i.sub.B, which, when measured in accordance with a
Hohenstein Institute standard test, ranges from 0 to 250.
26. The fabric according to claim 1, wherein the fabric has a drop
sorption index i.sub.B, which, when measured in accordance with a
Hohenstein Institute standard test, ranges from 0 to 5.
27. A fabric including: a) an inner face that is formed entirely
from one or more than one hydrophobic yarn and said yarns are
assembled over the inner face so that the inner face has a
hydrophobicity that is substantially the same over the inner
surface and is suitable for making the inside of a garment, wherein
said yarns include cotton and/or other types of cellulosic fibers
and have been pre-treated with a hydrophobic agent prior to
formation of the fabric; and b) an outer face that in comparison to
the inner face is relatively hydrophilic such that liquid can be
wicked through the inner face to the outer face, and wherein the
outer face is made of yarns that include cotton and/or other types
of cellulosic fibers.
28. The fabric according to claim 27, wherein the hydrophobic yarn
is pre-treated with a hydrophobic agent prior to formation of the
fabric.
29. The fabric according to claim 28, wherein fibers forming the
hydrophobic yarn are pre-treated with a hydrophobic agent when in
the form of a yarn.
30. The fabric according to claim 28, wherein the hydrophobic yarns
be pre-treated using an exhaust process.
31. The fabric according to claim 27, wherein the outer face of the
fabric is made from at least 50 percent hydrophilic yarns.
32. The fabric according to claim 27, wherein the outer face of the
fabric is formed from at least 80 percent hydrophilic yarn.
33. The fabric according to claim 27, wherein the outer face of the
fabric is formed from 100 percent hydrophilic yarn.
34. The fabric according to claim 27, wherein at least one of the
hydrophobic or hydrophilic yarns contains 50 percent cotton and/or
other types of cellulosic fibers.
35. The fabric according to claim 27, wherein at least one of the
hydrophobic or hydrophilic yarns contains at least 80 percent
cotton and/or other types of cellulosic fibers.
36. The fabric according to claim 27, wherein both of said yarns
are made entirely of cotton and/or other types of cellulosic
fibers.
37. The fabric according to claim 27, wherein the fabric has a
ratio of hydrophilic to hydrophobic yarns on a mass basis ranges
from 95:5 to 10:90 respectively.
38. The fabric according to claim 27, wherein the fabric has a
ratio of hydrophilic to hydrophobic yarns on a mass basis ranges
from 60:40 to 80:20 respectively.
39. The fabric according to claim 27, wherein the hydrophobic yarn
or yarns are assembled so that sections of hydrophobic yarn in the
inner face are separated by spaces through which liquid can
penetrate and make contact with the hydrophilic yarn or yarns that
form at least part of the outer face of the fabric and that, in
turn, can draw liquid to the outer face of the fabric.
40. The fabric according to claim 39, wherein the hydrophobic yarns
form loops or floats on the inner face and form said sections of
hydrophobic yarn separated by spaces through which liquid can
penetrate.
41. The fabric according to claim 39, wherein the spacing of said
sections of hydrophobic yarn on the inner face of the fabric ranges
from 0.01 to 25 mm in the wale or warp direction and ranges from
0.01 to 25 mm in the course or weft direction.
42. The fabric according to claim 39, wherein the spacing of said
sections of hydrophobic yarn on the inner face of the fabric ranges
from 0.1 to 2.5 mm in the wale or warp direction and ranges from
0.1 to 2.5 mm in the course or weft direction.
43. The fabric according to claim 27, wherein the hydrophobic and
hydrophilic yarns are intermeshed in a manner whereby the
hydrophilic yarns from part of a core or central region of the
fabric and the outer face of the fabric.
44. The fabric according to claim 27, wherein the hydrophilic yarn
is located at a distance ranging from 0.01 to 2.0 mm from an outer
plane of the inner face of the fabric.
45. The fabric according to claim 27, wherein the hydrophilic yarn
is located at a distance ranging from 0.01 to 1.0 mm from an outer
plane of the inner face of the fabric.
46. The fabric according to claim 27, wherein when worn against
skin or located against an object, hydrophilic yarn directly
contacts the skin or object without hydrophilic yarn directly
contacting the skin or object.
47. The fabric according to claim 27, wherein the fabric has a
buffering capacity against liquid water K.sub.f, which, when
measured in accordance with a Hohenstein Institute standard test,
ranges from 0.1 to 1.
48. The fabric according to claim 27, wherein the fabric has a
buffering capacity against liquid water K.sub.f, which, when
measured in accordance with a Hohenstein Institute standard test,
ranges from 0.9 to 1.
49. The fabric according to claim 28, wherein the fabric has a drop
sorption index i.sub.B, which, when measured in accordance with a
Hohenstein Institute standard test, ranges from 0 to 250.
50. The fabric according to claim 28, wherein the fabric has a drop
sorption index i.sub.B, which, when measured in accordance with a
Hohenstein Institute standard test, ranges from 0 to 5.
51. A method of making a fabric that is capable of wicking liquid
through an inner face to an outer face of the fabric, the method
includes the steps of: a) providing a hydrophilic yarn; b)
providing a hydrophobic yarn that has been pre-treated to render it
hydrophobic; and c) forming a fabric using said hydrophilic and
hydrophobic yarns, wherein the yarns are assembled relative to each
other such that the inner face of the fabric is made entirely from
the hydrophobic yarn and liquid can penetrate the inner face and
make contact with hydrophilic yarn that forms at least part of the
outer face of the fabric and that, in turn, can draw liquid through
the inner face to the outer face of the fabric.
52. The method according to claim 51, wherein some sections of
hydrophobic yarn in the inner face are separated by spaces through
which liquid can penetrate.
53. The method according to claim 51, wherein the hydrophilic and
hydrophobic yarns include any one or a blend of the following types
of fibers: a) man-made or synthetic fibers including, but not
restricted to, polyester, polyamide, polyurethane, polypropylene,
polyacrylonitrile polyvinylchloride and regenerated cellulose; and
b) natural fibers including proteinaceous fibers such as wool and
hair and cellulosic fibers such as cotton.
54. The method according to claim 51, wherein at least one of the
hydrophobic or hydrophilic yarns include cotton fibers and/or other
types of cellulosic fibers.
55. The method according to claim 51, wherein at least one of the
hydrophobic or hydrophilic yarns contains at least 50 percent
cotton and/or other types of cellulosic fibers.
56. The method according to claim 51, wherein at least one of the
hydrophobic or hydrophilic yarns contains at least 80 percent of
cotton fibers and/or other types of cellulosic fibers.
57. The method according to claim 51, wherein both of said yarns
are made entirely of cotton and/or other types of cellulosic
fibers.
58. The method according to claim 54, wherein step b) includes
pre-treating the fibers with a liquor containing a hydrophobic
agent and results in the hydrophobic agent being fixed to the
fibers.
59. The method according to claim 58, wherein the pre-treatment
involves contacting the fibers with the liquor using an exhaust
process.
60. The method according to claim 58, wherein the pre-treatment is
carried out at a temperature ranging from 10 to 110.degree. C.
61. The method according to claim 58, wherein the pre-treatment is
carried out at a temperature ranging from 20 to 70.degree. C.
62. The method according to claim 58, wherein the pre-treatment is
carried out at a starting temperature of 10.degree. C. increasing
at a rate ranging from 0.1 to 5.0 degrees per minute to a maximum
of 110.degree. C.
63. The method according to claim 58, wherein the pre-treatment is
carried out at a starting temperature of 20.degree. C. increasing
at a rate ranging from 0.5 to 1.5 degrees per minute to a maximum
of 70.degree. C.
64. The method according to claim 58, wherein the hydrophobic agent
used in the pre-treatment is any one or a combination of silicones,
fluorochemicals, oils, latexes and hydrocarbons.
65. The method according to claim 58, wherein the hydrophobic agent
included in the liquor is a fluoroacrylate polymer.
66. The method according to claim 58, wherein the liquor contains a
concentration of electrolyte that minimises undesired deposition of
hydrophobic agent or flocculation of hydrophobic agent and assists
in achieving uniformity of the deposition of the hydrophobic agent
throughout the yarns packages.
67. The method according to claim 58, wherein the liquid includes
an electrolyte in the form of sodium sulphate or magnesium
chloride.
68. The method according to claim 66, wherein the electrolyte
concentration in the liquor ranges from 0 to 20 g/l.
69. The method according to claim 66, wherein the electrolyte
concentration in the liquor ranges from 5 to 10 g/l.
70. The method according to claim 51, wherein the liquor includes a
cross-linking agent for forming bonds between the hydrophobic agent
and the cotton or other cellulosic fibers.
71. The method according to claim 70, wherein the cross-linking
agent is heat activated and the method also includes a heat curing
step in which the pre-treated yarn is heated to a temperature
ranging from 50 to 230.degree. C.
72. The method according to claim 70, wherein the curing step
involves heating the pre-treated yarn to a temperature ranging from
110 to 190.degree. C.
73. The method according to claim 71, wherein the heat curing step
is carried out for a period ranging from 1 second to 40
minutes.
74. A method of making a fabric that is capable of wicking liquid
through an inner face to an outer face of the fabric and the fabric
includes two or more than two yarns that include cotton fibers
and/or other types of cellulosic fibers, the method includes the
steps of: a) pre-treating cotton fibers and/or other types of
cellulosic fibers of at least one of the yarns with a liquor
containing a hydrophobic agent so as to impart hydrophobic
properties to the fibers; and b) forming a fabric from two or more
yarns of which at least one yarn includes the cotton fibers and/or
other types of cellulosic fibers pre-treated according to step a)
and, wherein the yarns are assembled relative to each other such
that the inner face of the fabric is made entirely from said yarn
containing fibers pre-treated according to step a)and that the
inner face of the fabric is hydrophobic compared to the outer face
and has a hydrophobicity that is substantially the same over the
inner face.
75. The method according to claim 74, wherein the step of
pre-treating the cotton fibers and/or other cellulosic fibers with
the liquor containing a hydrophobic agent results in the
hydrophobic agent being fixed to the fibers.
76. The method according to claim 74, wherein step a) is carried
out either before, during or after the cotton fibers and/or other
types of cellulosic fibers are spun into a yarn.
77. The method according to claim 74, wherein at least one of the
yarns contains at least 50 percent cotton and/or other types of
cellulosic fibers.
78. The method according to claim 74, wherein at least one of the
yarns contains at least 80 percent cotton and/or other cellulosic
fibers on a weight basis.
79. The method according to claim 74, wherein the yarns include
cotton fibers and/or other types of cellulosic fibers consist
entirely of cotton fibers.
80. The method according to claim 74, wherein step a) involves
submerging the cotton fibers in the liquor so that the hydrophobic
agent is preferentially adsorbed onto the cotton fibers from the
liquor.
81. The method according to claim 74, wherein step a) involves
contacting the fibers with the liquor using an exhaust process.
82. The method according to claim 74, wherein step a) is carried
out at a temperature ranging from 10 to 110.degree. C.
83. The method according to claim 74, wherein step a) is carried
out at a temperature ranging from 20 to 70.degree. C.
84. The method according to claim 74, wherein step a) is carried
out at a starting temperature of 10.degree. C. increasing at a rate
ranging from 0.1 to 5.0 degrees per minute to a maximum of
110.degree. C.
85. The method according to claim 74, wherein step a) is carried
out at a starting temperature of 20.degree. C. increasing at a rate
ranging from 0.5 to 1.5 degrees per minute to a maximum of
70.degree. C.
86. The method according to claim 74, wherein the liquor includes
any one or a combination of silicones, fluorochemicals, oils,
latexes and hydrocarbons.
87. The method according to claim 74, wherein the hydrophobic agent
included in the liquor is a fluoroacrylate polymer.
88. The method according to claim 74, wherein the hydrophobic agent
is capable of forming covalent bonds to the surface of cotton
and/or other types of cellulosic fibers treated according to step
a).
89. The method according to claim 74, wherein the liquor contains a
concentration of electrolyte that assists in achieving uniformity
of the deposition of the hydrophobic agent throughout the yarn
packages and minimises undesired deposition of polymer onto the
treatment vessel or flocculation of hydrophobic agent.
90. The method according to claim 89, wherein the electrolyte is
one or a combination of sodium sulphate or magnesium chloride.
91. The method according to claim 89, wherein the electrolyte
concentration ranges from 0 to 20 g/l.
92. The method according to claim 89, wherein the electrolyte
concentration ranges from 5 to 10 g/l.
93. The method according to claim 74, wherein liquor includes a
cross-linking agent for forming bonds between the hydrophobic agent
and the cotton or other cellulosic fibers.
94. The method according to claim 93, wherein the cross-linking
agent is heat activated.
95. The method according to claim 93, wherein the method includes a
heat curing step in which the pre-treated yarn is heated to a
temperature ranging from 50 to 230.degree. C.
96. The method according to claim 95, wherein the curing step
involves heating the pre-treated yarn to a temperature ranging from
110 to 190.degree. C.
97. The method according to claim 94, wherein the heat curing step
is carried out for a period ranging from 1 second to 40
minutes.
98. The method according to claim 94, wherein the heat curing step
is carried out over a time period that can range from 30 seconds to
20 minutes.
99. The fabric according to claim 1, wherein the outer face is
laminated or joined to a waterproof and/or a windproof breathable
membrane.
Description
RELATED APPLICATIONS
[0001] This application is a continuation-in-part of International
Patent Application No. PCT/AU2005/001638, designating the United
States, filed on Oct. 21, 2005, which claims the benefit of U.S.
Provisional Application No. 60/621,943, filed on Oct. 22, 2004.
FIELD OF THE INVENTION
[0002] The present invention relates to a new fabric and a method
of making the fabric that is capable of transferring liquid from an
inner face to an outer face of the fabric by wicking. According to
one particular preferred embodiment of the present invention, the
fabric consists entirely of cotton fibers and is suitable for
making sports garments or under garments that help keep a person
dry and comfortable.
BACKGROUND OF THE INVENTION
[0003] Cotton fiber in its raw state is coated by naturally
occurring waxes that make it hydrophobic. Once this coating is
removed, by scouring for example, the fiber surface is strongly
hydrophilic--more so than any non-cellulosic fiber. This high
surface energy brings positive benefits, but in some conditions,
significant disadvantages.
[0004] In low activity conditions where moisture in the clothing
microclimate is mostly in the form of vapour, cotton fabrics
adjacent to the skin moderate or `buffer` changes in moisture
vapour extremely well due to the hygroscopic properties of cotton
fibers, hence the widely recognised `breathable` reputation of
cotton. As moisture levels rise and liquid sweat is formed, cotton
wicks sweat off the skin quickly and easily. However, in conditions
where large amounts of sweat are excreted, liquid bridges are
formed between the skin and fabric, thereby causing the fabric to
stick and drag on the skin during movement, a phenomenon known as
"wet cling". The high surface energy and fine diameter of cotton
fibers also causes cotton fabrics to have a high storage capacity
for liquids. Cotton fabrics hold more liquid than equivalent
fabrics of other fibers when saturated and therefore take
significantly longer to dry. As a result, cotton is generally
perceived as a relatively "low-tech" product when compared to
modern synthetics.
[0005] Synthetic polymers typically have relatively low surface
energy. In order to improve their wicking performance, they are
often treated with hydrophilic finishes of one form or another to
increase the fiber surface energy, although they do not reach the
same level as cotton. Wet cling is much less of a problem. In some
of the more technically-oriented synthetic products, multi-layer
structures consisting of fibers of different surface energies
and/or different fiber diameters are used to create a wicking
gradient between the inner surface and the outer surface of the
fabric so that sweat is preferentially transported away from the
skin. Moisture transport that occurs preferentially from one face
of the fabric to the other is known as differential wicking and
fabrics that achieve differential wicking by the use of layers of
different fiber diameters are generally known as denier gradient
fabrics.
[0006] U.S. Patent Application 2002/0064639 describes several
multi-layered fabrics comprising cellulosic fibers designed to
reduce wet cling. One particular type of fabric that is the focus
of the U.S. application comprises wicking windows that extend from
the inner surface of the fabric to the outer surface of the fabric
for transferring liquid from the inner surface to the outer
surface. The fabric is made by applying a hydrophobic agent in a
discontinuous manner to the inner surface to form regions of low
surface energy and thereby leaving untreated regions of relatively
high surface energy that form wicking windows. In reality, control
of the coating process described in the U.S. application is
extremely difficult as during application the hydrophobic agent
will tend to follow the same path into the fabric as sweat would
normally use, blocking off much of the wicking capability. During
wear, once the fabric is saturated, the wicking windows will also
be wet so the fabric is unlikely to feel dry against the skin. As
the sweat is distributed homogeneously throughout all parts of the
fabric not affected by the hydrophobic treatment, fabrics of this
type cannot be considered to be true differential wicking
structures.
SUMMARY OF THE INVENTION
[0007] The present invention is based on the realization that
improved wicking of liquid from an inner face to an outer face of a
fabric can be achieved by a fabric structure where the inner face
of the fabric has a substantially uniform hydrophobicity and where
the inner face is formed by hydrophobic yarn that is assembled in a
manner that allows the liquid to penetrate the inner face and make
contact with hydrophilic yarn that forms at least part of the outer
face of the fabric. When liquid penetrates the inner face and makes
contact with the hydrophilic yarn, the liquid can be drawn through
the inner face to the outer face of the fabric.
[0008] According to the present invention there is provided a
fabric including:
[0009] a) an inner face that is formed entirely from one or more
than one hydrophobic yarn that has been treated to render it
hydrophobic and said yarn or yarns are assembled over the inner
face so that the inner face has a hydrophobicity that is
substantially the same over the inner face; and
[0010] b) an outer face that in comparison to the inner face is
hydrophilic and is formed at least in part by one or more than one
hydrophilic yarn,
[0011] wherein the hydrophobic yarn or yarns are assembled so that
liquid can penetrate the inner face and make contact with the
hydrophilic yarn or yarns that form at least part of the outer face
of the fabric and that, in turn, can draw liquid to the outer face
of the fabric.
[0012] It is preferred that the hydrophobic yarn or yarns be
assembled so that some sections of hydrophobic yarn in the inner
face are separated by spaces through which the liquid can
penetrate.
[0013] Throughout this specification the terms "spaces or spacings"
between the hydrophobic yarns refers to the distance between the
outer surfaces of the yarns.
[0014] The hydrophilic and hydrophobic yarns may include, but are
not restricted to, any one or a blend of the following types of
fibers: a) man-made or synthetic fibers including polyester,
polyamide, polyurethane, polypropylene, polyacrylonitrile,
polyvinylchloride and regenerated cellulose; and b) natural fibers
including proteinaceous fibers such as wool and hair and cellulosic
fibers such as cotton.
[0015] In the situation where man-made fibers or filaments are
included in the hydrophobic yarn that forms the inner face of the
fabric, it is preferred that the man-made yarn be treated with a
hydrophobic agent.
[0016] If required, synthetic fibers may also be treated with a
hydrophilic agent when incorporated in one of the hydrophilic
yarns.
[0017] However, non-cellulosic man-made fibers lack the well
recognized moisture buffering capacity of cotton and other
cellulosic fibers. This has led us to conclude that an optimal
fabric will preferably be one that is made of cotton fibers and
modified cotton fibers that possesses some of the liquid wicking
properties of some technical synthetic fabrics.
[0018] The following phrase, or variations thereof that describe
the fabric as having "a hydrophobicity that is substantially the
same over the inner face" is used throughout the specification.
When the fabric is worn directly against the skin the phrase is
intended to refer to the situation whereby all points of contact
between the inner face of the fabric and skin are with said
hydrophobic yarns that form the inner face of the fabric. The
phrase embraces variations in hydrophobicity that may, for example,
arise due to operational characteristics and limitations of the
methods and processes used to create the hydrophobic properties of
the yarns forming the inner face of the fabric. It is possible that
a hydrophobic agent may be applied to yarns forming the inner face
of the fabric using any of the following known techniques: padding,
foam application, lick rollers, dip-hydro, spraying, printing or
doctor blade. It is also possible that the yarns may be treated
when assembled as a fully formed fabric or as individual yarns
prior to being assembled into a fabric.
[0019] An example of a technique for creating a fabric having an
inner face formed from hydrophobic yarns and having substantially
the same hydrophobicity over the inner face is to laminate two
separate fabric layers, one being a hydrophobic layer and another
being a hydrophilic layer that have been separately manufactured
and treated prior to being laminated together to form a complete
fabric having an inner face and an outer face. In particular the
fabric layer intended to form the inner face of the laminated
fabric assembly can be treated as a fully formed fabric with a
hydrophobic agent before lamination using any one or more of the
known processes and techniques described above. The treated fabric
layer may then be laminated with the other fabric layer that has
not been treated with a hydrophobic agent using suitable adhesion
techniques.
[0020] However, the preferred technique is for the pre-treated
hydrophobic yarns to be woven or knitted together with one or more
than one hydrophilic yarn.
[0021] It is preferred that the hydrophobic yarns be pre-treated
with a hydrophobic agent prior to formation of the fabric.
[0022] Although it is possible that the fibers of the hydrophobic
yarns may be treated with a hydrophobic agent while in the form of
loose fibers, or at any other stage prior to the formation of a
yarn such as a sliver or roving, it is preferred that the fibers be
pre-treated with a hydrophobic agent when in the form of a
yarn.
[0023] It is preferred that the outer face of the fabric be made
predominantly from hydrophilic yarns. This can be at least in part
achieved by utilising the naturally hydrophilic cellulose surface
of the cotton fibers and/or other types of cellulosic fibers. The
fibers may need to be scoured to remove any hydrophobic
contaminants such as, natural waxes in the case of cotton. In other
words, the yarns forming the outer layer are preferably not
pre-treated with the hydrophobic agent that is used to treat the
yarns forming the inner layer.
[0024] Throughout this specification the term "predominantly" is
used to describe on a proportional basis the quantity of a
particular feature. For example, in the situation where the outer
face of the fabric is described as being made predominantly from
hydrophilic yarn, the outer face includes at least 50 percent
hydrophilic yarns on a weight basis.
[0025] It is more preferred that the outer face of the fabric be
formed from 80 percent hydrophilic yarn.
[0026] It is even more preferred that the outer face of the fabric
be formed from 100 percent hydrophilic yarn.
[0027] It is preferred that the hydrophobic yarns be pre-treated
using an exhaust process.
[0028] Although it has been stated above that the yarns may include
man-made fibers including synthetic fibers and natural fibers such
as wool, it is preferred that the fibers include cotton fibers
and/or other types of cellulosic fibers.
[0029] It is even more preferred that the yarns contain at least 50
percent cotton and/or other types of cellulosic fibers. Cellulosic
fibers other than naturally occurring cotton fibers, include, but
are by no means limited to: mercerised cotton, jute, hemp, flax,
ramie, linen or regenerated cellulosic fibers such as viscose,
rayon and lyocell.
[0030] It is more preferred that the yarns contain at least 80
percent cotton and/or other types of cellulosic fibers.
[0031] It is even more preferred that the yarns be made entirely of
cotton and/or other types of cellulosic fibers. Simialarly, the
fabric when fully formed may also be made entirely of cotton and/or
other types of cellulosic fibers.
[0032] One of the advantages provided by the fabric of the present
invention when made entirely of cotton and/or other cellulosic
fibers is that the fabric is not at risk of melting and burning
skin, that is a characteristic of many commercially available
fabrics that utilize fiber denier gradients or differences in fiber
surface energy between layers to create differential wicking.
Differential wicking through the use of denier gradients is
generally achieved with fabric structures made from thermoplastic
synthetic fibers. Other fabric structures that use combinations of
layers of synthetic and natural fibers to achieve differential
wicking generally have the synthetic layer on the inner face of the
fabric that contacts the skin.
[0033] The danger with thermoplastic synthetic fibers against skin
is that the fibers can absorb enough energy to melt during exposure
to intense heat sources such as a fire during an emergency
situation. The resulting molten synthetic material can then adhere
to skin and when it re-solidifies, the latent heat of fusion
released can cause severe burns. In light of the natural resistance
of cotton and other cellulosic fibers to melting, in the situation
where the fabric of the present invention is formed from yarns that
are entirely made of cotton and/or other types of cellulosic
fibers, the fabric is well suited to clothing emergency service
personnel and military personnel as well as others.
[0034] It is preferred that the pre-treated hydrophobic yarns and
hydrophilic yarns be intermeshed within the fabric so as to bring
the hydrophilic yarn close to but not into the inner face of the
fabric.
[0035] It is preferred that the ratio of hydrophilic to hydrophobic
yarns on a mass basis ranges from 95:5 to 10:90 respectively.
[0036] It is even more preferred that the ratio of hydrophilic to
hydrophobic yarns on a mass basis ranges from 60:40 to 80:20
respectively.
[0037] An advantage of managing the ratio of the hydrophobic to
hydrophilic yarns is that the wicking behaviour and liquid storage
capacity of the fabric can be optimized.
[0038] It is preferred that the hydrophobic yarn or yarns are
assembled over the inner face of the fabric so as to form loops or
floats on the inner face and thereby form said sections of
hydrophobic yarn separated by spaces. In this instance, the loops
or floats provide structures between which liquid can penetrate to
pass through the hydrophobic inner face of the fabric.
[0039] Depending on the particular application of the fabric, for
example, when the fabric is being worn directly against the skin of
the person, sweat excreted by a person wearing the fabric may be
subject to pressure by virtue of the fabric bearing against the
skin of the person and by the flexing of the fabric as the person
moves. Pressure on sweat droplets of this nature may also force or
assist the liquid to penetrate between the hydrophobic yarn
formations on the inner face. In the situation where the fabric is
worn as a second or third layer of clothing, the fabric is unlikely
to have direct contact against the skin of the person. However, the
same principles can still apply and liquid contacting the inner
face of the fabric will be subject to pressure at least when the
fabric is flexed and changes shape during movement.
[0040] Once the liquid has made contact with a hydrophilic yarn, we
have realized that the liquid may be completely wicked from the
inner face of the fabric to the outer face without continuous
external pressures and forces that may have assisted in the liquid
penetrating between the hydrophobic yarns to initiate wicking. In
other words, once wicking has commenced it can continue until all
of the liquid in contact with the inner face is transferred to the
outer face or the capacity of the hydrophilic yarns to store liquid
is exhausted.
[0041] It is preferred that the spacing of the sections of
hydrophobic yarn on the inner face of the fabric range from 0.01 to
25 mm in the wale or warp direction and range from 0.01 to 25 mm in
the course or weft direction. The term "spacing" refers to the
distance between the outer surface of the yarns rather than the
centre-to-centre distance.
[0042] It is even more preferred that the spacing of the sections
of hydrophobic yarn on the inner face of the fabric is between 0.1
and 2.5 mm in the wale or warp direction and between 0.1 and 2.5 mm
in the course or weft direction.
[0043] In the situation when the fabric is worn directly against
the skin all points of contact between the inner face of the fabric
and skin are with the hydrophobic yarns that form the inner face of
the fabric. In other words, when a person wears the fabric, it is
preferred that the hydrophobic yarns contact the skin of the person
without hydrophilic yarns directly contacting the skin of the
person. An advantage provided by this preferred aspect of the
invention is that although the fabric itself may contain a large
amount of liquid, the greater part of this liquid is redistributed
to the outer face, so that a person wearing the fabric will not
feel the fabric wet as only relatively dry hydrophobic yarns are in
contact with the person's skin. This advantage may also be
expressed in terms of the re-drying time of the fabric, that is,
the time for a fabric in contact with skin to dry or at least feel
drier than other commercially available wicking fabrics.
[0044] The hydrophobic and hydrophilic yarns are preferably
intermeshed in a manner whereby the hydrophilic yarns from part of
a core or central region of the fabric and the outer face of the
fabric. The hydrophilic yarn does not appear in the inside face of
the fabric but is located below the surface at points where liquid
penetrating the hydrophobic face can make contact with it.
[0045] It is preferred that the hydrophilic yarn be located at a
distance ranging from 0.01 to 2.0 mm from an outer plane of the
inner face of the fabric.
[0046] It is even more preferred that the hydrophilic yarn be
located at a distance ranging from 0.1 to 1.0 mm from an outer
plane of the inner face of the fabric.
[0047] Examples of knitted fabric structures that may be employed
in forming the fabric include both all-needle and half-gauge double
knits, single jersey plated structures, and collapsed rib
structures involving elastomeric yarns. Examples of woven fabric
structures that may be employed in forming the fabric include
twills, sateens, satins and double cloths.
[0048] It is preferred that the fabric has a buffering capacity
against liquid water K.sub.f, which, when measured in accordance
with a Hohenstein Institute standard test, ranges from 0.1 to
1.
[0049] It is even more preferred that the fabric has a buffering
capacity against liquid water K.sub.f, which, when measured in
accordance with a Hohenstein Institute standard test, ranges from
0.9 to 1.
[0050] It is also preferred that the fabric has a drop sorption
index i.sub.B, which, when measured in accordance with a Hohenstein
Institute standard test, ranges from 0 to 250.
[0051] It is even more preferred that the fabric has a drop
sorption index i.sub.B, which, when measured in accordance with a
Hohenstein Institute standard test, ranges from 0 to 5.
[0052] The Hohenstein Institute standard tests referred to in the
preceding paragraphs are described in more detail on pages 31 and
32 under the heading
DETAILED DESCRIPTION
[0053] According to the present invention there is also provided a
fabric including:
[0054] a) an inner face that is formed entirely from one or more
than one hydrophobic yarn and said yarns are assembled over the
inner face so that the inner face has a hydrophobicity that is
substantially the same over the inner surface and is suitable for
making the inside of a garment, wherein said yarns include cotton
and/or other types of cellulosic fibers and have been pre-treated
with a hydrophobic agent prior to formation of the fabric, and
[0055] b) an outer face that in comparison to the inner face is
relatively hydrophilic such that liquid can be wicked through the
inner face to the outer face, and wherein the outer face is made of
yarns that include cotton and/or other types of cellulosic
fibers.
[0056] According to the present invention there is provided a
fabric including:
[0057] a) an inner face that is hydrophobic and has a
hydrophobicity that is substantially the same over the inner face,
and is suitable for making the inside of a garment; and
[0058] b) an outer face that in comparison to the inner face is
hydrophilic whereby liquid contacting the inner face can be wicked
through the fabric to the outer face without being retained by the
inner face, and wherein the inner and outer faces of the fabric are
made of yarns that include cotton fibers and/or other types of
cellulosic fibers.
[0059] According to the present invention there is provided a
fabric including:
[0060] a) an inner face that is formed entirely from one or more
than one hydrophobic yarn and said yarn or yarns are assembled over
the inner face so that the inner face has a hydrophobicity that is
substantially the same over the inner face, and wherein said yarns
include cotton fibers and/or other types of cellulosic fibers;
and
[0061] b) an outer face that in comparison to the inner face is
hydrophilic whereby liquid contacting the inner face can be wicked
through the fabric to the outer face and wherein the outer face is
made of yarns that include cotton fibers and/or other types of
cellulosic fibers.
[0062] It is preferred that the hydrophobic yarns that are
assembled over the inner face of the fabric be intermeshed with the
hydrophilic yarns that form at least part of the outer face of the
fabric and the hydrophobic yarns are arranged so that liquid is
able to be drawn through the hydrophobic face by the hydrophilic
yarns.
[0063] According to the present invention there is also provided a
method of making a fabric that is capable of wicking liquid through
an inner face to an outer face of the fabric. The method includes
the steps of:
[0064] a) providing a hydrophilic yarn;
[0065] b) providing a hydrophobic yarn that has been treated to
render it hydrophobic; and
[0066] c) forming a fabric using said hydrophilic and hydrophobic
yarns, wherein the yarns are assembled relative to each other such
that the inner face of the fabric is made entirely from the
hydrophobic yarn and the hydrophobic yarns are arranged in the
inner face so that liquid can penetrate and make contact with
hydrophilic yarn that forms at least part of the outer face of the
fabric.
[0067] It is preferred that step b) include pre-treating fibers of
the hydrophobic yarn with a hydrophobic agent which results in the
hydrophobic agent being fixed to the fibers.
[0068] Preferably, the hydrophilic yarn does not appear in the
inner face of the fabric but is located below the surface and can
draw liquid through the inner face to the outer face of the
fabric.
[0069] It is preferred that the hydrophobic yarns are arranged so
that some sections of the hydrophobic yarn are separated by spaces
that liquid can penetrate.
[0070] It is preferred that the hydrophilic and hydrophobic yarns
include but are not limited to any one or a blend of the following
types of fibers:
[0071] a) man-made or synthetic fibers including polyester,
polyamide, polyurethane, polypropylene, polyacrylonitrile,
polyvinylchloride and regenerated cellulose; and
[0072] b) natural fibers including proteinaceous fibers such as
wool and hair and cellulosic fibers such as cotton.
[0073] According to the present invention there is provided a
method of making a fabric including one or more than one
hydrophobic yarn and one or more than one hydrophilic yarn that
includes cotton and/or other types of cellulosic fibers, the yarns
being woven or knitted together such that an inner face of the
fabric is formed entirely from the hydrophobic yarns so that the
hydrophobicity of the inner face is substantially the same over the
inner face and an outer face of the fabric that is, by comparison,
hydrophilic such that liquid can be wicked through the fabric from
the inner face to the outer face. The method includes the step of
pre-treating the cotton and/or other types of cellulosic fibers of
the hydrophobic yarn that forms the inner face of the fabric with a
liquor containing a hydrophobic agent prior to the yarn being used
to make the fabric.
[0074] Although it has been stated above that the yarns may include
man-made fibers including synthetic fibers and natural fibers such
as wool, it is preferred that the fibers include cotton fibers
and/or other types of cellulosic fibers.
[0075] It is even more preferred that at least one of the yarns
contain at least 50 percent cotton and/or other types of cellulosic
fibers.
[0076] Cellulosic fibers other than naturally occurring cotton
fibers include, but are by no means limited to: mercerised cotton,
jute, hemp, flax, ramie, linen or regenerated cellulosic fibers
such as viscose, rayon and lyocell.
[0077] It is more preferred that at least one of the yarns contain
at least 80 percent cotton and/or other types of cellulosic
fibers.
[0078] It is even more preferred that said yarns be made entirely
of cotton and/or other types of cellulosic fibers.
[0079] It is preferred that the step b) include pre-treating the
fibers with a liquor containing a hydrophobic agent and results in
the hydrophobic agent being fixed to the fibers.
[0080] According to the present invention there is also provided a
method of making a fabric that is capable of wicking liquid through
an inner face to an outer face of the fabric and the fabric
includes two or more than two yarns that include cotton fibers
and/or other types of cellulosic fibers. The method includes the
steps of:
[0081] a) pre-treating the scoured cotton fibers and/or other types
of cellulosic fibers of at least one of the yarns with a liquor
containing a hydrophobic agent so as to impart hydrophobic
properties to the fibers; and
[0082] b) forming a fabric from two or more yarns of which at least
one yarn includes the cotton fibers and/or other types of
cellulosic fibers pre-treated according to step a) and, wherein the
yarns are assembled relative to each other such that the inner face
of the fabric is made entirely from said yarn containing fibers
pre-treated according to step a) and that the inner face of the
fabric is hydrophobic compared to the outer face and has a
hydrophobicity that is substantially the same over the inner
face.
[0083] It is preferred that the step of pre-treating the cotton
fibers and/or other cellulosic fibers with the liquor containing a
hydrophobic agent results in the hydrophobic agent being fixed to
the fibers.
[0084] Throughout this specification the phrase "the hydrophobic
agent being fixed onto the fibers" embraces any physical adsorption
or chemical reaction whereby the hydrophobic agent becomes fixed to
the cotton fiber. Examples of adsorption and reactions that may
cause the hydrophobic agent to become fixed to the cellulosic
fibers include, but are not limited to, ionic bonding and exchange,
covalent bonding and exchange, van der Waals (non-dispersive)
bonding and exchange or so called dipole-dipole bonding and
exchange and variations thereof.
[0085] It will be appreciated that step a) may be carried out
either before, during or after the cotton fibers and/or other types
of cellulosic fibers are spun into a yarn.
[0086] It is also possible that the cotton fibers and/or other
types of cellulosic fibers pre-treated according to step a) may be
provided in any form including loose fibers, sliver, rovings, spun
yarns, hanks, and even woven, knitted or non-woven fabric. However,
it is preferred that the fibers pre-treated according to step a) be
in the form of a spun yarn.
[0087] It is preferred that the yarns including cotton fibers
and/or other types of cellulosic fibers consist entirely of cotton
fibers. However, it is also possible that the yarns may include
blends of cotton fibers with other cellulosic fibers and
non-cellulosic fibers such as polyester. It is to be understood
that cellulosic fibers other than naturally occurring cotton fibers
include but are not limited to the following types of fibers:
mercerised cotton, jute, hemp, flax, ramie, linen or regenerated
cellulosic fibers such as viscose, rayon and lyocell.
[0088] In the situation in which the cotton fibers and/or other
types of cellulosic fibers pre-treated by step a) are in the form
of fabric, the fabric can be unravelled to form a continuous yarn
or thread that can be further processed with another yarn in
accordance with step b) of the method of the present invention. The
method whereby a knitted fabric is pre-treated then unravelled into
yarn and re-formed into fabric is known as the knit-de-knit
process.
[0089] It will also be appreciated that steps a) and b) may be
carried out consecutively or disjunctively.
[0090] It is possible that step a) may be carried out using various
techniques that allow the liquor to contact the cotton fibers
and/or other types of cellulosic fibers. For example, depending on
the form in which the fibers are provided, the liquor containing
the hydrophobic agent may contact the fibers by padding, rolling or
spraying the liquor onto the fibers. However, it is preferred that
step a)involves submerging the cotton fibers in the liquor so that
the hydrophobic agent is preferentially adsorbed onto the cotton
fibers from the liquor.
[0091] In the situation in which the fibers pre-treated by step a)
are in the form of a spun yarn wound onto a tube to form a yarn
package, it is preferred that step a) involves contacting the
fibers with the liquor using an exhaust process.
[0092] Exhaust processes are known at present as suitable for
applying dyestuffs to yarns and involve placing one or more than
one yarn package into an enclosed vessel that may be pressurized
and pumping the dyestuff through the yarns. It has been found that
a hydrophobic agent can be fixed to the fibers satisfactorily using
an exhaust process.
[0093] It is our understanding that exhaust processes provide a
more durable application of the hydrophobic agent compared to other
possible techniques such as padding, foam application, lick
rollers, dip-hydro, spraying, printing or doctor blade. As a
result, the wicking behaviour of the fabric manufactured from
fibers that have been subjected to exhaust treatment according to
this preferred embodiment can demonstrate a greater retention of
the wicking properties after numerous wash and wear cycles.
[0094] Although step a) may be carried out at any suitable
temperature, it is preferred that step a) be carried out at a
temperature ranging from 10 to 110.degree. C.
[0095] It is even more preferred that step a) be carried out at a
temperature ranging from 20 to 70.degree. C.
[0096] It is preferred that step a) be carried out at a starting
temperature of 10.degree. C. increasing at a rate ranging from 0.1
to 5.0 degrees per minute to a maximum of 110.degree. C.
[0097] It is even more preferred that step a) be carried out at a
starting temperature of 20.degree. C. increasing at a rate ranging
from 0.5 to 1.5 degrees per minute to a maximum of 70.degree.
C.
[0098] Examples of hydrophobic agents that may be used in step a)
of the present invention include but are not limited to any one or
a combination of silicones, fluorochemicals, oils, latexes and
hydrocarbons. It is preferred that the hydrophobic agent included
in the liquor be a fluoroacrylate polymer.
[0099] An advantage provided by the preferred hydrophobic agent is
that the fabric can be piece dyed using conventional dyestuffs such
as reactive dyes without shade differences between treated and
untreated yarns in the same fabric. In addition, the dyeing
treatment does not change the wicking mechanism of the fabric.
[0100] The useable life of the new fabric made by the method of the
present invention is determined by the number of wash and wear
cycles that can be endured before wicking of liquid no longer
preferentially occurs from the inner face to the outer face. This
in turn is a function of the resistance of the hydrophobic agent to
physical damage and/or leaching during the washing process.
[0101] In order to prolong the wicking characteristics of the
fabric, it is preferred the hydrophobic agent be capable of forming
covalent bonds to the surface of cotton and/or other types of
cellulosic fibers treated according to step a).
[0102] The rate of uptake of the hydrophobic agent from the liquor
and the uniformity of the deposition of the hydrophobic agent
throughout the yarn packages may be dependent on the availability
of an electrolyte. Similarly, depending on the nature of the
hydrophobic agent used, the ability to completely exhaust the
hydrophobic agent from the liquor and to avoid undesired deposition
of polymer onto the treatment vessel or flocculation of hydrophobic
agent, the liquor may need to contain an electrolyte.
[0103] It is preferred that the treatment liquor also includes an
electrolyte. The electrolyte may be any suitable electrolyte such
as sodium sulphate or magnesium chloride.
[0104] In the situation where the liquor includes an electrolyte it
is preferred that step a) involve controlling the concentration of
electrolyte in the solution. Controlling the concentration may be
required to achieve both uniform application of the hydrophobic
agent and complete exhaustion of the hydrophobic agent from the
liquor.
[0105] It is preferred that the electrolyte concentration range
from 0 to 20 g/l.
[0106] It is even more preferred that the electrolyte concentration
range from 5 to 10 g/l.
[0107] Irrespective of whether the hydrophobic agent may or may not
be able to form covalent bonds with cotton or other types of
cellulosic fibers, in order to further increase the stability and
therefore the duration over which the hydrophobic agent is
effective, it is preferred that the treatment liquor include a
cross-linking agent for forming bonds between the hydrophobic agent
and the cotton or other cellulosic fibers. Hydrophobic agents that
contain isocyanate cross-linkers that bond the fiber and/or to the
substratate may be beneficial to this treatment.
[0108] In addition, it is possible the cross-linking agent may also
become fixed to the cellulosic fiber itself. For example, a
cross-linking agent may react with the hydroxyl groups present on
the surface of the cotton fibers and/or other types of cellulosic
fibers.
[0109] The principal advantage in using a cross-linking agent is to
increase the durability of the hydrophobic agent to laundering.
[0110] It is even further preferred that the cross-linking agent be
heat activated.
[0111] In order to activate the cross-linking agent, it is
preferred that the method also include a heat curing step in which
the pre-treated yarn is heated to a temperature ranging from 50 to
230.degree. C.
[0112] It is even more preferred that the curing step involve
heating the pre-treated yarn to a temperature ranging from 110 to
190.degree. C.
[0113] The heat curing step may be carried out for any suitable
period; however, periods ranging from 1 second to 40 minutes are
preferred. It is more preferred that the heat curing step is
carried out for a time period ranging 30 seconds to 20 minutes or
any period within that range.
[0114] The heat curing step may be carried out at a variety of
different stages of the method of the present invention, such as
either before or after step b). In the instance in which the fabric
is knitted, it has been found that a knitting lubricant can be
applied to a yarn pre-treated according to step a) to facilitate
knitting and the knitting lubricant can subsequently be removed
using conventional scouring techniques before or after curing
without adversely effecting the hydrophobic pre-treatment. In this
situation, the curing step is carried out after step b).
[0115] Similarly, it is also possible for the heat curing step to
be carried out before the yarn is knitted or woven with another
yarn.
[0116] According to the present invention there is also provided a
garment including the fabric as described above. The fabric from
which the garment is made may also include any one or a combination
of the preferred or optional features described above. Although the
garment may be any outer garment such as a pair trousers, a shirt
or a jacket, it is preferred that the garment be a base layer
garment worn against the skin. Fabrics as described herein may also
be used as a component of an item of clothing or clothing system.
For example, these fabrics can be laminated to one face of a
functional film together with a second fabric on the other face
using well know lamination technology such as adhesive printing or
coating. They can also be used as both faces of such a construction
to produce a reversible fabric. The functional film can be a
waterproof and/or windproof breathable membrane. Liquid sweat
picked up is transported to the hydrophilic layer next to the
adjoining functional film and can influence the breathability of
the film in a positive way. Laminated fabrics of this type are well
suited for industrial and outdoor sports applications.
BRIEF DESCRIPTION OF THE DRAWINGS
[0117] The present invention will now be described with reference
to the accompanying diagrams, of which:
[0118] FIG. 1 is a structural profile of a section of fabric in
accordance with an embodiment of the invention;
[0119] FIGS. 2 and 3 are flow diagrams illustrating the method
steps for making a fabric according to alternative embodiments of
the invention; and
[0120] FIGS. 4 and 5 show a structural profile of a section of
fabric in accordance with an embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0121] A preferred embodiment of the present invention will now be
described with reference to the fabric structure shown in FIG. 1.
The fabric is preferably made from two or more yarns consisting
entirely of cotton yarns. However, it will be appreciated that it
is within the scope of the present invention that the cotton yarns
may be partially or completely substituted with other types of
cellulosic fibers or even synthetic fibers. In other words, other
embodiments of the present invention may have yarns that are made
entirely of man-made fibers or blends of the synthetic and
cellulosic fibers.
[0122] The fabric shown in FIG. 1 includes an inner face generally
identified by reference numeral 10 that is made entirely from yarns
containing cotton fibers that prior to fabric formation have been
pre-treated in the form of a yarn with a hydrophobic agent in
accordance with the method described herein. The pre-treated yarn
exhibits a substantially permanent hydrophobic property and is
arranged such that the inner face 10 of the fabric has a
substantially uniform hydrophobic surface. In contrast, an outer
face of the fabric identified by reference numeral 20 is made from
yarns containing cotton fibers that are not pre-treated with a
hydrophobic agent and have been scoured so that they exhibit the
natural hydrophilic properties of the cellulosic surface. The
difference in hydrophilicity or surface energy between the inner
face 10 and outer face 20 of the fabric enables liquid to be wicked
through the fabric from inside to outside in the direction of the
arrows 30 shown in FIG. 1.
[0123] The fabric preferably has a layered structure in which the
hydrophobic and hydrophilic cotton yarns 11 and 12 respectively are
intermeshed within the fabric so as to bring the hydrophilic yarn
12 toward the inner face 10 of the fabric but not actually form
part of that face 10. More particularly, as shown in FIG. 1, it is
preferred that the hydrophobic yarn 11 be assembled so as form
loops or floats 13 that form the inner face 10 of the fabric. The
loops and floats 13 are spaced sufficiently apart to allow liquid
such as sweat drops to penetrate between the loops and floats 13
and when located between the loops 13 the liquid is able to make
contact with the hydrophilic yarn 12 that forms part of the outer
face of the fabric. Once the liquid has made contact with the
hydrophilic yarn 12, the hydrophilic yarn 12 draws liquid through
the inner face 10 to the outer face 20 of the fabric. External
pressure applied to the liquid such as pressure on the liquid
caused by movement between the fabric and skin of a person wearing
the fabric. In any event once the wicking path is created, wicking
can continue until all the liquid is removed from the inner face 10
of the fabric or until the capacity of the hydrophilic yarn 12 to
store liquid is exhausted.
[0124] Although the structural profile shown in FIG. 1 illustrates
the loops or floats 13 separated over by relatively consistent
spaces, it will be appreciated that the spacing between the
hydrophobic yarn of a fabric is likely to vary at least to some
extent in view of current manufacturing variables including yarn
tension and diameter. In addition, depending on the particular
fabric structure chosen it is possible for the fabric pattern to
having two or more than two loops 13 immediately adjacent to one
another at regular intervals, yet be spatially separated from
neighbouring loops. In any event, the nett result is that the inner
face 10 of the fabric has a hydrophobicity that is substantially
the same over the inner face 10 and the loops 13 are assembled so
that sections of the hydrophobic yarn 11, typically the loops 13,
are separated so as to form spacing or voids without hydrophobic
yarns in the inner face 10 into which liquid can penetrate and make
contact with the hydrophilic yarn 12. The liquid can then be wicked
to the outer face of the fabric as described above.
[0125] FIG. 2 is a flow diagram according to an embodiment of the
present invention in which cotton fibers spun into yarns are wound
onto one or more tubes to form yarn packages at a first stage. The
yarn packages are initially scoured then treated with liquor
containing a hydrophobic agent, so that the agent is adsorbed
directly onto the cotton fibers. The hydrophobic agent is
preferably a fluoroacrylate polymer. In addition, the liquor may
include a heat-activated cross-linking agent that is applied to the
cotton yarn during the hydrophobic pre-treatment stage.
[0126] The liquor preferably includes the hydrophobic agent as an
emulsion. The rate at which the hydrophobic agent is deposited onto
the cotton fibers and the uniformity of the deposition of the
hydrophobic agent throughout the yarn packages will depend on a
number of operational parameters including the size and
concentration of the particles in the emulsion, the residence time
or period over which the yarns are treated, the temperature of the
liquor and the rate at which the temperature is raised between a
start temperature and a finish temperature. The rate of uptake of
the particles from the emulsion is also a function of the
concentration of electrolyte, such as sodium sulphate, contained by
the liquor. Indeed, in order to achieve complete exhaustion of the
particles from the liquor, an optimal concentration of electrolyte
may be required to avoid flocculation of hydrophobic agent or
deposition of the hydrophobic agent on equipment items.
[0127] It is preferred that the particle size of this emulsion at
room temperature is less than 500 nm. It is even more preferred
that the particle size of the emulsion at room temperature is less
than 240 nm and most preferred if the size is less than 120 nm.
[0128] Following the hydrophobic agent pre-treatment stage the
cotton yarns are processed in a heat curing oven to activate the
cross-linking agent. When activated the cross-linking agent can
form bonds between the hydrophobic agent adsorbed onto the cotton
fibers and depending on the type of the cross-linking agent, it may
itself also bond with the cotton fiber. In any event, the purpose
of the cross-linking agent is to further increase the resistance of
the hydrophobic treatment to laundering. Preferably, the heat
curing stage heats the cotton fibers to a substantially uniform
temperature of approximately 150.degree. C. In order to achieve a
substantially uniform temperature in the least amount of time the
yarn may be unwound from each yarn package.
[0129] A friction-reducing knitting lubricant is then applied to
the pre-treated yarn and the yarn knitted with a second,
hydrophilic cotton yarn to form a fabric into a differential
wicking structure. The fabric is then scoured to remove the
knitting lubricant prior to the fabric being converted into a
garment. We have found that with some hydrophobic agents the
knitting lubricant can be removed by scouring without adversely
affecting the performance of the hydrophobic agent.
[0130] The hydrophobic treatment stage may be carried out using any
suitable technique that allows the hydrophobic agent to contact and
become fixed to the cotton fibers. Examples of possible types of
techniques that may be employed for contacting the fibers with the
liquor include padding, foam application, lick rollers, dip-hydro,
spraying, printing and doctor blade. However, it is preferred that
the liquor contacts the cotton fibers by submerging the cotton
fibers in the liquor. An example of a process in which fibers are
submerged in a liquid is an exhaust process. Conventionally,
exhaust processes have been used for dyeing fibers with colour
dyestuffs.
[0131] FIG. 3 is a flow diagram of an alternative embodiment that
is the same as the embodiment shown in FIG. 2, save for the heat
curing step being carried out on the cotton yarn after the
hydrophobic yarn has been formed into a fabric. Specifically, FIG.
3 illustrates a method including the stages of: i) spinning and
winding a cotton yarn onto a tube; ii) scouring the yarn to remove
surface contaminants; iii) adsorbing a hydrophobic agent onto the
cotton yarn in a pre-treatment stage; iv) knitting or weaving the
pre-treated yarn with at least one other yarn so as to make a
fabric; v) removing lubricants and other processing aids from the
fabric using conventional scouring techniques; vi) heat curing the
hydrophobic agent and cross-linking agent if present; and finally
converting the fabric into a garment.
[0132] Although not shown in either FIG. 2 or 3, it is also
possible that the heat curing stage may be carried out before the
scouring. In addition, it is also possible that the liquor
containing the hydrophobic and cross-linking agents may also
include a knitting lubricant that is applied to the cotton yarns
during the hydrophobic pre-treatment stage.
[0133] The superior wicking performance of a fabric manufactured
according the embodiment of the present invention described above
can be demonstrated by a test that assesses the relative amounts of
water in the inner and outer faces of the fabric after contact with
water. The test method may be summarised as follows. Initially test
specimens of fabric (measuring 100 mm.times.100 mm) are selected
and stored at relative humidity of 65% at 20.degree. C. for a
period of 4 hours prior to testing to ensure homogeneous moisture
content in the fabric. A fixed volume of water is then placed near
the centre of the inside face of each specimen using a pipette.
After the water has been totally absorbed, the fabric is sandwiched
between two pieces of absorbent paper and laid flat for a short
time with pressure applied uniformly over the surface. The weight
of water absorbed by each piece of paper is measured and recorded.
The ratio of these two weights is quoted as the mass wicking ratio.
The test is repeated with the opposite face upward and the results
averaged to eliminate gravitational effects.
[0134] An alternative means of assessing the effect of differential
wicking is to measure the area of spread of the water on each face
of test specimens prepared as described in the preceding test
immediately after a fixed volume of water has been fully absorbed.
The ratio of these two areas is quoted as the area wicking
ratio.
[0135] The table set out below provides the results of the wicking
performance of 5 different types of fabrics. Fabric type 1 is a
conventional 100% cotton fabric. Fabric type 2 is a prior art
cotton fabric that has a hydrophobic layer printed on the inner
face of the fabric in accordance with other commercially available
fabrics. Fabric type 3 is a cotton fabric comprising a hydrophobic
inner face made from a hydrophobic yarn in accordance with an
embodiment of the present invention. Fabric type 4 is a prior art
fabric comprising an inner face made with a polypropylene yarn and
an outer face made with a cotton yarn. Fabric type 5 is a prior art
fabric in the form of a polyester double-knit. TABLE-US-00001 Mass
wicking ratio Fabric type outer:inner 1 1.0 2 5.0 3 33 4 7.9 5
1.0
[0136] The invention will now be further described with reference
to the following non-limiting examples, which are provided for
illustration purposes only and are not to be interpreted as
defining the scope of the invention.
EXAMPLE 1
[0137] This example demonstrates fabrication of a double knit
fabric manufactured from hydrophilic cotton yarn for the outer face
and hydrophobic cotton yarn for the inner face. Both yarns are
first scoured and bleached using a conventional cotton procedure.
This renders the surface of the cotton hydrophilic. The yarn to be
used for the inner face of the fabric is then treated with Nuva TTC
(Clariant) by an exhaust process using the apparatus and method
described above to render it hydrophobic. The yarn package size
used is 900 g wound to a density of 0.3 g/cc and the yarn is
treated under the follows conditions: TABLE-US-00002 Liquor ratio
12:1 Nuva TTC 5% on mass of yarn Sodium Sulphate 8 g/l Start
temperature 20.degree. C. Finish temperature 70.degree. C.
Temperature increase 0.5.degree. C./min Hold time at 70.degree. C.
15 min Liquor flow cycle 4 minutes out-to-in, 3 minutes
in-to-out
[0138] The liquor clears progressively during the treatment cycle
and at the end of the treatment time, the liquor is completely
clear, indicating that exhaustion onto the yarn is complete.
[0139] The liquor is drained from the apparatus without rinsing and
the yarn packages hydro-extracted and dried at 80.degree. C. The
yarn is then rewound and waxed with a paraffin lubricant prior to
knitting.
[0140] Fabric manufacture is carried out on a double-jersey
knitting machine. After knitting, the fabric is scoured to remove
the knitting wax for 30 minutes at 65.degree. C. in the presence of
1 g/L Hostapal FA-Z (Clariant) and 1 g/L sodium carbonate. The
liquor is drained at a temperature of 65.degree. C. to prevent
re-deposition of the emulsified wax. The fabric is rinsed twice for
10 minutes at 40.degree. C., hydro-extracted and dried on a
stenter. During the drying process the fabric is subjected to a
temperature of 145.degree. C. for 5 minutes to cure the hydrophobic
agent.
[0141] The fabric exhibits differential wicking behaviour that is
retained for a minimum of 30 home laundry wash and tumble dry
cycles. Washing is carried out at 60.degree. C. using a 2A Cotton
Cycle in accordance with ISO 6330 with ECE detergent, while tumble
drying is carried out cool for 60 minutes.
EXAMPLE 2
[0142] This example is the same as Example 1, save for the step of
curing the fabric being carried out after knitting and before the
final scour to remove lubricant.
[0143] The fabric exhibits differential wicking behaviour that is
retained for a minimum of 30 home laundry wash and tumble dry
cycles. Washing is carried out at 60.degree. C. using a 2A Cotton
Cycle in accordance with ISO 6330 with ECE detergent, while tumble
drying is carried out cool for 60 minutes.
EXAMPLE 3
[0144] This example is the same as Example 1, except for the
softener/lubricant Sandolube SVN being co-applied with the
hydrophobic agent atthe rate of 1% on mass of fiber during the yarn
treatment step. The Sandolube replaces the paraffin knitting
lubricant added during re-winding in Example 1.
[0145] The fabric exhibits differential wicking behaviour that is
retained for a minimum of 30 home laundry wash and tumble dry
cycles. Washing is carried out at 60.degree. C. using a 2A Cotton
Cycle in accordance with ISO 6330 with ECE detergent, while tumble
drying is carried out cool for 60 minutes.
EXAMPLE 4
[0146] In this example, finished fabric prepared using the
procedure described in Example 1 is piece dyed using a conventional
reactive dyeing procedure applicable to cotton goods.
[0147] The fabric exhibits differential wicking behaviour that is
retained for a minimum of 30 home laundry wash and tumble dry
cycles. Washing is carried out at 60.degree. C. using a 2A Cotton
Cycle in accordance with ISO 6330 with ECE detergent, while tumble
drying is carried out cool for 60 minutes.
EXAMPLE 5
[0148] This example is the same as Example 1, save for both yarns
being dyed prior to treatment and knitting into fabric using
conventional cotton colouration technology. In this instance, the
preparatory scouring and bleaching step are not required. The yarn
to be used for the hydrophobic face is given a mild scour with
sodium carbonate to remove any residual contaminants and loose
dyestuff prior to treatment with the hydrophobic agent. The fabric
exhibits the required differential wicking behaviour for a minimum
of 30 home laundry wash and tumble dry cycles. Washing is carried
out at 60.degree. C. using a 2A Cotton Cycle in accordance with ISO
6330 with ECE detergent, while tumble drying is carried out cool
for 60 minutes.
EXAMPLE 6
[0149] This example is the same as Example 1, save for the
hydrophobic yarn being prepared by a knit-de-knit process with the
hydrophobic agent applied to the fabric by a conventional
pad/dry/cure process. The cotton yarn used for the hydrophobic face
is first scoured and bleached then knitted into a single jersey
tube on a single-feed FAK laboratory machine. Nuva TTC is padded
onto the tubular fabric piece at 5% on mass of fabric by means of a
small mangle. The fabric is subsequently dried and the polymer heat
cured. The yarn is unravelled from the piece (de-knitted), re-wound
and waxed in preparation for knitting.
[0150] The fabric exhibits differential wicking behaviour that is
retained for a minimum of 30 home laundry wash and tumble dry
cycles. Washing is carried out at 60.degree. C. using a 2A Cotton
Cycle in accordance with ISO 6330 with ECE detergent, while tumble
drying is carried out cool for 60 minutes.
EXAMPLE 7
[0151] In this example the yarn to be used for the inner face of
the fabric is treated with Ruco-Dry DFE (Rudolf Chemie) as a
hydrophobic agent. The method and apparatus for carrying out the
manufacture and all operating conditions of the treatment process
are the same as described in Example 1, save for the following
treatment conditions: TABLE-US-00003 Liquor ratio 10:1 Ruco-Dry DFE
5% on mass of yarn Start temperature 25.degree. C. Finish
temperature 40.degree. C. Temperature increase 1.5.degree. C./min
Hold time at 40.degree. C. 10 min
The fabric exhibits the required differential wicking behaviour for
a minimum of 30 home laundry wash and tumble dry cycles. Washing is
carried out at 60.degree. C. using a 2A Cotton Cycle in accordance
with ISO 6330 with ECE detergent, while tumble drying is carried
out cool for 60 minutes.
EXAMPLE 8
[0152] This example demonstrates fabrication of a double knit
fabric manufactured from 1/30s Cotton Count (20 Tex) hydrophilic
cotton yarn for the outer face and 1/50s Cotton Count (12 Tex)
hydrophobic cotton yarn for the inner face. Both yarns are scoured
and the hydrophobic yarn treated as for Example 1.
[0153] Fabric manufacture is carried out on a double-jersey
knitting machine of 28 needles per inch (28 gauge). At the first
knitting point or feed, the hydrophilic yarn is knitted on all
needles on one needle bed only. This is repeated at the next feed.
At the third feed, the hydrophobic yarn is knitted on alternate
needles of the second needle bed and tucked across to alternate
needles of the first bed. This sequence is repeated for the next
group of three feeds on the knitting machine, except that the
hydrophobic yarn is tucked to those needles omitted at the
preceding hydrophobic course. The fabric has a mass ratio of
hydrophilic yarn to hydrophobic yarn of 75:25.
[0154] The liquid water buffering index K.sub.f of the fabric when
measured by the procedure described on page 27 is 0.99 and its
moisture sorption index i.sub.B is 0.7, both of which are within
the range of preferred values for these properties. The mass
wicking ratio determined by the test method described above is
18:1. Differential wicking behaviour is retained for in excess of
30 cycles of home laundering and tumble drying. Washing is carried
out at 60.degree. C. using a 2A Cotton Cycle in accordance with ISO
6330 with ECE detergent, while tumble drying is carried out cool
for 60 minutes.
EXAMPLE 9
[0155] This example demonstrates fabrication of a double knit
fabric manufactured from a hydrophilic 78 dtexpolyester (PES)
filament yarn for the outer face and Ne 1/50s Cotton Count (12 Tex)
hydrophobic cotton yarn for the inner face. The hydrophobic yarn is
scoured and treated as in Example 1. In this example an Elasthane
yarn is worked up between the outer hydrophilic face and the inner
hydrophobic face.
[0156] Fabric manufacture is carried out on a double-jersey
knitting machine of 28 needles per inch (28 gauge). At the first
knitting point or feed, the hydrophilic yarn is knitted on all
needles on one needle bed only. This is repeated at the next feed.
At the third feed, the hydrophobic yarn is knitted on alternate
needles of the second needle bed and tucked across to alternate
needles of the first bed. This sequence is repeated for the next
group of three feeds on the knitting machine, except that the
hydrophobic yarn is tucked to those needles omitted at the
preceding hydrophobic course. The fabric has a mass ratio of
hydrophilic yarn to hydrophobic yarn and Elasthane of 45:45:10.
[0157] The liquid water buffering index K.sub.f of the fabric when
measured by the procedure described below is 0.95 and its moisture
sorption index i.sub.B is 0.7, both of which are within the range
of preferred values for these properties. The mass wicking ratio
determined by the test method described above is 19:1. Differential
wicking behaviour is retained for in excess of 30 cycles of home
laundering and tumble drying. Washing is carried out at 60.degree.
C. using a 2A Cotton Cycle in accordance with ISO 6330 with ECE
detergent, while tumble drying is carried out cool for 60
minutes.
[0158] The use of PES yarn for the outer face is advantageous
because a PES yarn is known as a fast drying yarn and therefore the
outer face is able to dry very fast. Furthermore the "cotton
feeling" on the skin is maintained.
EXAMPLE 10
[0159] This Example demonstrates fabrication of a double knit
fabric manufactured from Nm 66 wool yarn for the outer face and
1/50s Cotton Count (12 Tex) hydrophobic cotton yarn for the inner
face. The hydrophobic yarn is scoured and treated as in Example 1.
In this example an Elasthane yarn is worked up between the outer
hydrophilic face and the inner hydrophobic face.
[0160] Fabric manufacture is carried out on a double-jersey
knitting machine of 28 needles per inch (28 gauge). At the first
knitting point or feed, the wool yarn is knitted on all needles on
one needle bed only. This is repeated at the next feed. At the
third feed, the hydrophobic yarn is knitted on alternate needles of
the second needle bed and tucked across to alternate needles of the
first bed. This sequence is repeated for the next group of three
feeds on the knitting machine, except that the wool yarn is tucked
to those needles omitted at the preceding hydrophobic course. The
fabric has a mass ratio of wool yarn to hydrophobic yarn and
Elasthane of 60:30:10.
[0161] The liquid water buffering index K.sub.f of the fabric when
measured by the procedure described below is 0.9 and its moisture
sorption index i.sub.B is 4.5 both of which are within the range of
preferred values for these properties. The mass wicking ratio
determined by the test method described above is 12:1. Differential
wicking behaviour is retained for in excess of 30 cycles of home
laundering and tumble drying. Washing is carried out at 60.degree.
C. using a 2A Cotton Cycle in accordance with ISO 6330 with ECE
detergent, while tumble drying is carried out cool for 60
minutes.
[0162] The use of wool yarn is advantageous because wool has very
high insulation properties which are useful for specific outdoor
applications, like alpin skiing, ice climbing etc. Furthermore,
this combination of yarns provides the wearer with the preferred
cotton feeling on the skin.
EXAMPLE 11
[0163] This Example demonstrates fabrication of a double weave
structure manufactured from hydrophilic cotton yarn for the outer
face and hydrophobic cotton yarn for the inner face. The
hydrophilic cotton yarn is a Nm 64/2 yarn and the hydrophobic yarns
are a mixture out of different yarn counts: Nm 64/2, Nm 32/2, Nm
112/2 yarn. Other embodiments may have hydrophilic yarns that are
made of wool or synthetic fibers like PES.
[0164] Both yarns are scoured and the hydrophobic yarn treated as
in Example 1. Fabric manufacture is carried out on a double weave
machine.
[0165] A double weave fabric may be defined as a compound woven
fabric where two sets of warp yarns and weft yarns allow the outer
face and the inner face of the fabric to show different patterns or
have different properties. One set of warp and weft yarns
preferably comprises hydrophilic cotton yarns (forming the outer
face) and the other set or yarns preferably comprise hydrophobic
cotton yarns (forming the inner face). In a double weave fabric,
the fabric has two fabric layers and some yarns from one fabric
layer interlace with the other fabric layer so that the fabrics
layers are held together. Preferably some yarns from the outer
hydrophilic fabric layer interlace with the inner hydrophobic
fabric layer in such a way that no hydrophilic yarns are present on
the inner surface.
[0166] The outer face of the double weave fabric has a Twill of 2/1
and the inner face has a Twill with a rib-structure. The fabric has
a mass ratio of hydrophilic yarn to hydrophobic yarn of 60:30.
[0167] The liquid water buffering index K.sub.f of the fabric when
measured by the procedure described below is 0.99 and its moisture
sorption index i.sub.B is 0.7, both of which are within the range
of preferred values for these properties. The mass wicking ratio
determined by the test method described above is 18:1. Differential
wicking behaviour is retained for in excess of 30 cycles of home
laundering and tumble drying. Washing is carried out at 60.degree.
C. using a 2A Cotton Cycle in accordance with ISO 6330 with ECE
detergent, while tumble drying is carried out cool for 60
minutes.
[0168] FIGS. 4 and 5 show one embodiment of this example of the
double weave fabric.
[0169] FIG. 4 shows schematically a top view of the inner
hydrophobic face of a section of the double weave woven fabric
according to Example 4. The double weave fabric comprising a first
hydrophobic fabric layer 105 and a second hydrophilic fabric layer
(not visible in the drawing). The first hydrophobic fabric layer
105 includes an inner face 100 that is made entirely from yarns
containing cotton fibres that prior to fabric formation have been
pre-treated in the form of a yarn with a hydrophobic agent in
accordance with the method described above. The hydrophobic warp
yarns 112 and hydrophobic weft yarns 114 are woven together forming
the first fabric layer 105. The second hydrophilic fabric layer
(not visible) comprising hydrophilic cotton yarns and is arranged
behind the first fabric layer. The hydrophilic warp yarns and
hydrophilic weft yarns are woven together forming the second fabric
layer. Some hydrophilic yarns 122 from the outer second fabric
layer interlace with the inner hydrophobic fabric layer 105
permanent within the layered structure of the fabric so as to bring
the hydrophilic yarn 122 toward the inner face 100 of the fabric
but not actually form part of that face 100.
[0170] More particularly as shown in FIG. 4, the hydrophobic warp
yarns 112 are spaced sufficiently apart to allow liquid such as
sweat drops to penetrate between the hydrophobic warp yarns 112 and
when located between the hydrophobic yarns the liquid is able to
make contact with the hydrophilic yarn 122 that forms part of the
outer face of the fabric. Such space has the reference number 200.
Once the liquid has made contact with the hydrophilic yarn 122, the
hydrophilic yarn 122 draws liquid through the inner face 100 to the
outer face of the fabric. In any event once the wicking path is
created, wicking can continue until all the liquid is removed from
the inner face 100 of the fabric or until the capacity of the
hydrophilic yarn 122 to store liquid is exhausted.
[0171] Although the structural top view shown in FIG. 4 illustrates
the warp yarns 112 or weft yarns 114 separated over by relatively
consistent spaces, it will be appreciated that the spacing between
the hydrophobic yarn of a fabric is likely to vary at least to some
extent in view of current manufacturing variables including yarn
tension and diameter. In any event, the result is that the inner
face 100 of the double weave fabric has a hydrophobicity that is
substantially the same over the inner face 100 and the hydrophobic
warp yarns 112 and weft yarns 114 are assembled so that sections of
the hydrophobic yarn 112, 114 typically the warp yarns 112, are
separated so as to form spacing or voids 200 into which liquid can
penetrate and make contact with the hydrophilic yarn 122. The
liquid can then be wicked to the outer face of the fabric as
described above.
[0172] FIG. 5 is a structural profile of a section of a double
weave fabric in accordance with Example 4 of the invention.
[0173] Those skilled in the art of the present invention will
appreciate that many modifications may be made to the preferred
embodiment without departing from the spirit and scope of the
present invention.
[0174] It is preferred that fabrics manufactured in accordance with
the present invention satisfy performance criteria that can be
measured in accordance with standard tests of the Hohenstein
Institute of Bonnigheim, Germany. The tests are designed to rate
the liquid water wicking and drying behaviour of fabrics and may be
summarized as follows:
1. The Buffering Capacity against Liquid Water, K.sub.f
[0175] This test is described in Standard Test Specification BPI
1.2 `Testing of Textiles--Measurement of the Buffering Capacity of
Textiles with the Thermoregulatory Model of Human Skin (Skin
Model)`, Bekleidungsphysiologisches Institut E. V. Hohenstein,
March 1994.
[0176] The determination of K.sub.f is carried out on a guarded hot
plate located within a climate-controlled cabinet. A system
incorporating these two items, known widely as the Hohenstein Skin
Model, has a specific configuration and a defined airflow across
the hot plate. The central plate dimensions are 20 cm.times.20 cm
and the plate is heated to a temperature of 35.degree. C. The
conditions within the cabinet are controlled at 35.degree. C. and
30% relative humidity. An impermeable film is placed on the surface
of the guarded hot plate and a thin, wicking polyester fabric is
placed over the film. Test specimens measuring 21 cm.times.21 cm
are used, pre-conditioned for 12 hours prior to the test at the
same temperature and humidity as the air in the cabinet. The
quantity of 15 cc of distilled water at a temperature of 35.degree.
C. is uniformly distributed over the polyester with a hypodermic
syringe and the test specimen is immediately placed over it,
centred on the plate.
[0177] Some of the water is absorbed or wicked up by the fabric,
some evaporates either at the plate or from the fabric and some
remains in the polyester. After a fixed 15-minute period, the
fabric is removed and weighed. The amount of water evaporated into
the cabinet G.sub.1 is determined from the mass of water removed
from the air in the cabinet in order to maintain constant humidity
conditions. The amount of water remaining in the fabric G.sub.2 is
determined by subtracting the conditioned mass of the specimen from
the final mass. The buffering index K.sub.f is the ratio of the sum
of these components to the initial mass G.sub.0. Thus: K f = G 1 +
G 2 G 0 ##EQU1## 2. The Drop Sorption Index, i.sub.B
[0178] This test is described in Standard Test Specification BPI
3.2 `Testing of Textiles--Measurement of the Sorption Index
i.sub.B, Bekleidungsphysiologisches Institut E. V. Hohenstein,
January 2003.
[0179] The test is carried out in an atmosphere of 20.degree. C.
and 65% relative humidity on fabric specimens approximately 2
cm.times.3 cm pre-conditioned for 24 hours. The specimens are fixed
onto a flat table with double-sided tape with the side normally in
contact with the skin facing upwards. A drop of distilled water of
volume 42 .mu.l is mechanically dispensed from a syringe located 5
cm above the centre of the test specimen at the rate of 13.76
.mu.l/s. The sorption index i.sub.B is the time taken for this drop
to be completely absorbed, that is, for the contact angle of the
drop i.sub.B to fall to 0.degree.. The drop rate is best monitored
by a software-controlled video camera system.
* * * * *