Note: Descriptions are shown in the official language in which they were submitted.
CA 02295261 2008-04-17
ELECTRIC HEATING/WARMING FABRIC ARTICLES
The invention relates to electric fabric articles
for heating/warming.
Background of the Invention
Techniques known for augmenting heating/warming
capabilities of clothing fabric include adding electric
wires to the fabric, typically by incorporating the wires
directly into the fabric or by attaching the wires to the
fabric, e.g., by sewing. It is also known, e.g., from
Gross et al. U.S. Patent No. 4,021,640, to print an
electrical circuit with a resistance heating element on a
sheet of plastic, such as MYLAR , and to incorporate
strips of the plastic sheet into a fabric article, such
as a glove.
Summary of the Invention
According to one aspect of the invention, an
electric heating/warming composite fabric article
comprises a fabric layer having an inner surface and an
outer surface, a barrier layer disposed at the inner
surface of the fabric layer, the barrier layer having an
inner surface and an outer surface, and an electric
heating/warming element in the form of a flexible,
electricity-conducting film disposed upon the inner
surface of the barrier layer and adapted to generate
heating/warming when connected to a power source.
Preferably, the outer layer of the barrier layer is
secured at least adjacent, and, more preferably, secured,
to the inner surface of the fabric layer.
According to another aspect of the invention, an
electric heating/warming composite fabric article
comprises at least a fabric layer having an inner surface
and an outer surface, and an electric heating/warming
element in the form
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of a flexible, electricity-conducting film disposed upon the
inner surface of the fabric layer and adapted to generate
heating/warming when connected to a power source.
Preferably, the composite fabric article further comprises a
barrier layer positioned at least adjacent to the inner
surface of the fabric layer.
Preferred embodiments of one or both aspects of the
invention may include one or more of the following
additional features. The film forming the electric
heating/warming element is also stretchable. The fabric
layer may be hydrophobic or hydrophilic. The barrier may be
micro-porous hydrophobic, e.g. poly tetrafluoroethylene
(PTFE), and/or nonporous hydrophilic, e.g. poly'urethane, or
a combination of both. The barrier layer is resistant to
passage of air and water droplets, and permeable to water
vapor. The electric heating/warming element is washable,
non-swelling and hydrophobic. The electric heating/warming
element is resistant to stiffening and cold crack. The
electric heating/warming element has resistivity in the
range of about 100 (1x102) ohm-cm to 0.000001 (1x10-6) ohm-
cm. The electricity-conducting film comprises synthetic
resin, preferably containing conductive particles, e.g.,
comprising at least one of silver and graphite.
According to another aspect of the invention, a
method of forming an electric heating/warming composite
fabric article comprises providing a fabric layer having an
inner surface and an outer surface and a barrier layer
having an inner surface and an outer surface, joining the
inner surface of the fabric layer to the outer surface of
the barrier layer, applying an electricity-conducting paste
upon the inner surface of the barrier layer in a
predetermined pattern of an electric circuit, and curing the
electricity-conducting paste to form an electric
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heating/warming element in the form of a flexible,
electricity-conducting film defining an electric circuit
upon the inner surface of the barrier layer, the electric
heating/warming element being adapted for connection to a
power source, thereby to generate heating/warming.
According to another aspect of the invention, a
method of forming an electric heating/warming composite
fabric article comprises providing a barrier layer having an
inner surface and an outer surface, applying an electricity-
conducting paste upon the inner surface of the barrier layer
in a predetermined pattern of an electric circuit, curing
the electricity-conducting paste to form an electric
heating/warming element in the form of a flexible,
electricity-conducting film defining an electric circuit
upon the inner surface of the barrier layer, providing a
fabric layer having an inner surface and an outer surface,
and joining the inner surface of the fabric layer to the
outer surface of the barrier layer, the electric
heating/warming element being adapted for connection to a
power source, thereby to generate heating/warming.
According to yet another aspect of the invention, a
method of forming an electric heating/warming composite
fabric article comprises providing a fabric layer having an
inner surface and an outer surface, applying an electricity-
conducting paste upon the inner surface of the fabric layer
in a predetermined pattern of an electric circuit, and
curing the electricity-conducting paste to form an electric
heating/warming element in the form of a flexible,
electricity-conducting film defining an electric circuit
upon the inner surface of the fabric layer, the electric
heating/warming element being adapted for connection to a
power source, thereby to generate heating/warming.
Preferably, the method further comprises the steps of:
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providing a barrier layer having an inner surface and an
outer surface, and positioning the outer surface of the
barrier layer at least adjacent to the inner surface of the
fabric layer, to overlay at least a portion of the electric
heating/warming element.
Preferred embodiments of one or more of these
various aspects of the invention may include one or more of
the following additional features. During the curing step.
the electricity conducting paste is cured to form a
stretchable film defining the electric circuit. The method
comprises the further step of incorporating the electric
heating/warming composite fabric article into articles of
apparel, e.g. jackets, hats, gloves, shirts, pants, socks,
boots, and/or shoes, and/or into home furnishings textile
articles, e.g. blankets, warmers and/or seat pads. The
method comprises the further step of connecting the electric
heating/warming element to a power source, thereby to
generate heating/warming.
It is an objective of this invention to provide an
electric heating/warming composite fabric article which is
windproof, water-resistant and water vapor permeable, and,
in selected applications, stretchable.
It is a further objective of this invention to
provide an electric heating/warming element formed of a
material which is flexible, washable, non-swelling and
hydrophobic, and, preferably, stretchable, that may be
deposited on the surface of a fabric layer, or on the
surface of a barrier layer that is, or may after be, adhered
to a fabric layer.
Other objectives of the invention include to provide
a heating/warming composite fabric article which is
stretchable, making it comfortable to wear; to provide a
heating/warming composite fabric article which is
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waterproof, but also vapor permeable, e.g., making it
particularly suitable for use in winter garments; and to
provide a heating/warming composite fabric article in which
the heating/warming elements are resistant to stiffening and
cracking at low temperatures.
Other features and advantages of the invention will
be apparent from the following description of a presently
preferred embodiment, and from the claims.
Brief Description of the Drawings
Fig. 1 is a somewhat diagrammatic exploded side edge
view of the components forming a first embodiment of a
heating/warming composite fabric article constructed in
accordance with the invention;
Fig. 2 is a somewhat diagrammatic side edge view of
the heating/warming composite fabric article of Fig. 1; and
Figs. 3, 4 and 5 are somewhat diagrammatic front
plan views of the inner surfaces of heating/warming
composite fabric articles of Figs. 1 and 2, with electric
heating/warming elements formed thereupon, e.g., for a glove
(Fig. 3), for an article of footwear (Fig. 4), and for a
garment such as a shirt or jacket (Fig. 5); and
Fig. 6 is a somewhat diagrammatic front view of a
garment, i.e., a jacket, incorporating the heating/warming
composite fabric article of Fig. S.
Fig. 7 is a somewhat diagrammatic exploded side edge
view of the components forming another embodiment of a
heating/warming composite fabric article constructed in
accordance with the invention; and
Fig. 8 is a somewhat diagrammatic side edge view of
the heating/warming composite fabric article of Fig. 7.
Fig. 9 is a somewhat diagrammatic side edge view of
another embodiment of a heating/warming composite fabric
article constructed in accordance with the invention.
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Figs. 10 and 11 are sequential, somewhat
diagrammatic front plan views of the inner surface of a
heating/warming composite fabric article during construction
in accordance with another embodiment the invention.
Fig. 12 is a somewhat diagrammatic exploded side
edge view of the components forming another embodiment of a
heating/warming composite fabric article constructed in
accordance with the invention, while Figs. 13 and 14 are
somewhat diagrammatic side edge views of alternate
embodiments of the heating/warming composite fabric article
of Fig. 12.
Description of the Preferred Embodiments
Referring first to Figs. 1 and 2, in a first
embodiment, a stretchable, windproof, water-resistant, and
vapor permeable electric heating/warming composite fabric
article 10 constructed in accordance with this invention has
three major components. These components include a fabric
layer 12, a barrier layer 14 and an electric heating/warming
element 16, the fabric layer 12 and barrier layer 14 being
joined at opposed fabric inner surface 13 and barrier outer
15, respectively, by adhesive 18.
In preferred embodiments, the outer fabric layer 12
is made in any well known manner, e.g. the fabric layer 12
may be a knitted material, e.g., a plaited circular knitted
or reverse plaited circular knitted material, or other
circular knitted material (such as double knitted, single
jersey knitted, two-end fleece knitted, three-end fleece
knitted, terry knitted or double loop knitted material), or
warp knitted or weft knitted material, or a woven or non-
woven material. In applications where the fabric layer 12
of the fabric article 10 will be directed outwardly, away
from the wearer's skin, the material of the fabric layer is
preferably hydrophobic, in order to resist penetration of
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liquids. In other applications, where the fabric layer 12
of the fabric article 10 will be directed inwardly, toward
the wearer's skin, the material of the fabric layer is
preferably naturally hydrophilic, chemically rendered
hydrophilic, or hydrophobic, in order to enhance removal and
transport of perspiration away from the skin. The inner
surface 13 of fabric layer 12, to which the adhesive 18 is
adhered, is preferably flat. The exposed, outer surface 20
of fabric layer 12 may be flat or raised, e.g. by brushing,
sanding or napping, and/or may be otherwise provided with
decorative and functional features and finishes, e.g. as
well known in the art.
Preferably, the barrier layer 14 is formed of a
vapor permeable membrane which is nonporous hydrophilic or
micro-porous hydrophobic or a combination of both, e.g. in
layers, as appropriate to the nature of the intended use, or
as otherwise desired. In many embodiments, it is also
preferred that the material of the barrier layer 14 be soft
and stretchable. The barrier layer is constructed and/or
formulated to resist air and water droplets from passing
through the composite fabric article 10 while being
permeable to water vapor. In applications where it is
desired that the fabric article 10 is stretchable, the
fabric layer 12 may typically be a knitted material, and a
preferred material for barrier layer 14 is poly urethane,
e.g. as available from UCB Chemical Corp. of Drogenbos,
Belgium, either micro-porous hydrophobic (preferred for use
where the barrier layer 14 is directed outward) or nonporous
hydrophilic (preferred for use where the barrier layer 14 is
directed inward). Alternatively, in situations where
relatively less stretch is required, e.g. in footwear, the
fabric layer 12 may be a warp knitted material, and a
preferred material for barrier layer 14 is poly
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tetrafluoroethylene (PTFE), e.g., as available from
Tetratec, of Feasterville, Pennsylvania.
The barrier layer 14 is joined to the inner surface
13 of fabric layer 12 by adhesive 18, typically applied
in spots, lines or other discrete regions, or by
attachment, lamination or other suitable manner of
combining. A similar composite fabric (but having an
additional internal fabric layer) is described in
commonly assigned Lumb et al. U.S. Patent No. 5,364,678.
Referring also to Fig. 3, electric heating/warming
element 16 is disposed upon the outer surface 22 of
barrier layer 14. The electric heating/warming element 16
is preferably formed of an electrically conductive paste
having sufficient electrical resistivity when deposited
upon the surface of the barrier layer to generate a level
of heat/warmth suitable for its intended purpose. For
example, electrical resistivity of the conductive paste
after printing and curing in the range of 100 (1x102)
ohm-cm to 0.000001 (1x10"6) ohm-cm is considered suitable
for use in most applications; however, conductive pastes
performing outside this range can be employed, where
required or desired. In the preferred embodiment, the
paste is a silicone-based resin containing silver,
graphite and/or other conductive particles, e.g. as
available under the designation X171484 from Loctite
Corporation, of Rocky Hill, Connecticut.
Preferably, the heating/warming element 16 is
applied upon the surface 22 in the form of a paste by
screen printing in a predetermined pattern. After the
paste is applied upon the surface 22 of the barrier layer
14, the paste is cured to form the heating/warming
element 16 as a thin film which is very flexible and can
be bent and/or
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stretched without cracking or otherwise adversely affecting
the electrical circuit. After curing, the fabric article
10, including the heating/warming element 16 thereupon, is
washable, and the heating/warming element 16 is non-swelling
and hydrophobic. Preferably, the conductive paste is
formulated also to resist stiffening and cracking upon
exposure to low temperatures, e.g. such as those experienced
in northern climes.
The predetermined screen printing pattern of the
heating/warming element 16 may be custom designed for the
particular use and purpose of the garment for which the
composite fabric article 10 of the invention is to be used.
For example, the pattern of the heating/warming'element 16
of the composite fabric article 10 of Fig. 3 is designed for
use in making a glove. For this purpose, the electric
heating/warming element 16 is printed to form a pattern
having four elongated branches 28A, 28B, 28C, 28D
(corresponding to fingers of a glove) and one or more
labyrinth or zig-zag sections 28F (corresponding to the palm
or back of the body of a glove). The heating/warming
element 16 is formed as a continuous filament or circuit,
terminating at each end in a contact pad 28G, 28H,
respectively, which preferably are disposed adjacent to each
other in a region convenient for connection to a source of
power, e.g. for a glove, as shown, in a region to form the
wrist of the glove. Still referring to Fig. 3, the
heating/warming element 16 is connected, by wire conductors
30, 32 extending from contact pads 28G, 28H, respectively,
in a circuit including a switch 34 and a power supply, e.g.,
a battery pack 36. When switch 34 is closed, the
heating/warming element 16 is activated to generate
heat/warmth.
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The pattern features of the heating/warming element
16 shown in Fig. 3 are sized and shaped to conform to the
regions of the resulting fabric article, i.e., the glove, so
that the composite fabric can readily be cut to form one
side of a glove. Patterns for use in other types and sizes
of garments and fabric articles, e.g. such as socks,
sweaters, jackets, shirts, pants, hats, gloves, footwear
(e.g. shoes and boots) and so on, can be generated in a
similar manner.
For example, referring to Fig. 4, a composite fabric
article 40 of the invention has a heating/warming element 42
sized and shaped to conform to the regions of the selected
resulting fabric article, i.e., in this embodiment, a boot,
to be heated/warmed so that the composite fabric can readily
be cut to be formed and/or incorporated into a boot liner.
In particular, the heating/warming element 42 has
heating/warming regions 44, 45 of concentrated zig-zag
conductor filaments corresponding to the toe/ball and heel
surfaces, respectively, of a wearer's foot. The
heating/warming element 42, which is formed as a continuous
circuit, terminates at each end in a contact pad 46, 47,
respectively, which are disposed adjacent to each other in a
region convenient for connection to a source of power, e.g.,
as shown, in a region to extend into or above the ankle
collar of the boot.
Referring finally to Fig. 5, a composite fabric
article 50 of the invention has a heating/warming element 56
sized and shaped to conform to the regions of the selected
resulting fabric article, i.e., in this embodiment, the
opposite chest surfaces of a garment such as a shirt or a
jacket 60 (Fig. 6), to be heated/warmed. The
heating/warming element 56, which is formed as a continuous
circuit, terminates at each end in a contact pad 58, 59,
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respectively, which are disposed adjacent to each other in a
region convenient for connection to a source of power, as
discussed below.
Referring also to Fig. 6, a pair of fabric articles
50 are shown incorporated into jacket 60. A battery pack 68
for powering each of the heating/warming composite fabric
articles 50 is contained in the associated zippered pockets
70, 71. The battery pack 68, e.g. as available from
Polaroid Corporation, of Cambridge, Massachusetts, is
preferably removably connected to the contact pads 58, 59 of
heating/warming element 56 by releasable fastening elements
72, e.g. clips, snaps or other secure but releasable
fastening elements. (The fastening elements may provide the
electrical connection of the battery pack to the circuit,
or, alternatively, may maintain the battery pack in position
for contact of the battery pack with separate connectors.)
This arrangement permits the battery pack 68 to be removed,
e.g., whenever the fabric article 50 is to be washed, or for
replacement. The heating/warming circuit 56 may also
include an oscillator chip 74 or other timing or cycling
device for cycling application of electrical power from the
battery pack 68 to the heating/warming element 56, e.g., to
extend battery pack life. For example, a timing cycle of
three minutes "on" followed by one minute "off" is
considered suitable for an electric heating/warming
composite fabric article 50 incorporated as a chest panel of
the heating/warm jacket 60 suited for outdoors use.
In one preferred embodiment, a composite fabric
article 10 of the invention is formed by first combining the
fabric layer 12 and barrier layer 14 with adhesive 18
disposed therebetween. An electric heating/warming element
16 is then formed, e.g. by screen printing a conductive
paste in a predetermined pattern, on the surface 22 of the
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.' s
barrier layer 14. The printed pattern is then cured to form
an electric heating/warming element 16 which is flexible,
washable, non-swelling and hydrophobic, which is also
resistant to stiffening or cracking at lower temperatures,
and which preferably is also stretchable. The resulting
composite fabric article 10 is cut to shape, and otherwise
processed using standard clothing procedures, for
incorporation, e.g., into an article of clothing or the
like.
Alternatively, the heating/warming element 16 may be
formed on the surface 22 of the barrier layer 14 and cured,
before the barrier layer 14 and the fabric layer 12 are
secured together.
Referring next to Figs. 7 and 8, in another
embodiment of the invention, an electric heating/warming
composite fabric article 110 consists of a fabric layer 112
having an inner surface 114 upon which is applied, e.g. as a
conductive paste, by screening printing, an electric
heating/warming element 116.
In embodiments of the invention where the
heating/warming element 116 is applied directly to the
fabric layer 112, the composite fabric article 110 may be
employed without a barrier layer. Alternatively, a pair of
fabric articles 110 may be incorporated into garment, e.g. a
jacket 60, as shown in Fig. 6, where the outer coverings 62,
64 of the opposite chest surfaces of the jacket may be a
shell material selected to provide a barrier layer
overlaying the heating/warming composite fabric articles 110
incorporated into the jacket.
The relative amounts of heat/warmth generated by a
region of an electrical heating/warming element in a
composite heating/warming fabric article of the invention
can be controlled, e.g., by varying the length and/or width
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and/or thickness of a circuit element filament or segment,
and/or by varying the conductivity/resistivity of the
material forming a segment of the circuit element. For
example, referring to Fig. 5, a heating/warming element 56
is formed of a paste material of uniform conductivity
applied to form a film of constant thickness having regions
80 and 82 of contrasting width, and, therefore, contrasting
cross sectional area. As a result, in region 80 of
relatively greater width, there is more conductivity, i.e.
less resistance to current flow, and thus less generation of
heat/warmth. Similarly, in region 82 of relatively lesser
width, there is less conductivity, i.e. more resistance to
current flow, and thus relatively greater generation of
heat/warmth. As a result, a composite heating/warming
fabric article 50 of the invention can be designed with a
circuit element 56 that delivers relatively greater amounts
of heat/warmth to selected regions of the wearer's body.
In other embodiments, this effect may also or
instead be achieved by concentrating a relatively greater
length of relatively narrow circuit element filaments, e.g.
in a tortuous, zig-zag and/or interlocking spiral pattern,
in a region of greater heat requirement. For example,
referring to Fig. 4, a zig-zag circuit pattern is provided
in regions 44, 45 corresponding to toe/ball and heel
surfaces, respectively, of a composite heating/warming
fabric article 40 of the invention, i.e., a boot liner; and
also, referring to Fig. 3, in the fingertip regions 24 and
hand surface region 26 of a composite heating/warming fabric
article 10 of the invention, i.e., a glove.
Alternatively, this effect may be obtained by
applying a thinner region of conductive paste, i.e., a
region of relatively lesser cross sectional area. For
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example, referring to Fig. 9, a composite heating/warming
fabric article 10' of the invention has a heating/warming
element 16' having a region 90 of relatively lesser "
thickness (compared to adjacent regions). Alternatively, or
in addition, a heating/warming element of constant dimension
but with regions generating relatively different levels of
heat/warmth may be formed by sequentially applying circuit
regions using pastes of inherently different conductivity.
For example, referring first to Fig. 10, showing a composite
heating/warming fabric article 100 of the invention, a
heating/warming element 102 is formed by first applying
regions 104, 106 of a conductive paste of relatively greater
conductivity, and thereafter, referring to Fig.'11, applying
region 108 of a conductive paste of relatively lower
conductivity, region 108 interconnecting regions 104, 106,
with the conductive pastes being applied, e.g., in the
manner in which contrasting colors are applied, in
sequential steps in a screen printing process. These and
other methods for adjusting the conductivity of electrical
circuit regions may be employed alone, or in any desired
combination.
In yet another embodiment of the invention, the
electric heating/warming composite fabric article 110
described above with reference to Figs. 5 and 6 may be
further processed. For example, referring now to Figs. 12,
13 and 14, in an electric heating/warming composite fabric
article 120, a barrier layer 122, e.g. as described above,
is attached adjacent to the side of the inner surface 114 of
the fabric layer, overlying at least a portion of the
heating/warming element 116, using adhesive, also as
described above. Preferably, contact pads 118 (only one is
shown) of heating/warming element 116 are left exposed for
connection to a source of power (Fig. 13), or electrical
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connectors 124 (only one is shown) are provided for
connecting the contact pads and power source through the
barrier layer 122 (Fig. 14).
In all cases described above, the heating/warming
layer is supported by a fabric layer, whether or not a
barrier layer is provided. The fabric layer may be
naturally hydrophilic, chemically rendered hydrophilic, or
hydrophobic. In most preferred embodiments, a barrier layer
is provided at least adjacent to the inner surface of the
fabric layer, i.e., attached to the fabric layer (with or
without intervening materials) or spaced from attachment to
or upon the fabric layer, but positioned at the inner
surface side of the fabric.
Other embodiments are within the following claims.
For example, the conductive paste may instead be an
electrical conductive synthetic resin, e.g. poly aniline,
alone or containing conductive particles. Also, additional
fabric layers may be added to enhance various esthetics and
functional characteristics of the electric heating/warming
composite fabric article.
What is claimed is:
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