U.S. patent application number 13/360644 was filed with the patent office on 2012-05-24 for material for use with a capacitive touch screen.
Invention is credited to Gerald Leto, Donald Joseph Wager.
Application Number | 20120128995 13/360644 |
Document ID | / |
Family ID | 43298156 |
Filed Date | 2012-05-24 |
United States Patent
Application |
20120128995 |
Kind Code |
A1 |
Leto; Gerald ; et
al. |
May 24, 2012 |
Material for use with a capacitive touch screen
Abstract
A modified material for use with a capacitive touch screen is
described. The modified material comprises a material impregnated
with a composition comprising either a non-metallic and/or a
metallic conductive agent with a binder. A variety of materials are
contemplated, including, but not limited to leather. Also described
is an apparatus and method of providing a conductive glove is
disclosed.
Inventors: |
Leto; Gerald; (San Jose,
CA) ; Wager; Donald Joseph; (San Jose, CA) |
Family ID: |
43298156 |
Appl. No.: |
13/360644 |
Filed: |
January 27, 2012 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
13307681 |
Nov 30, 2011 |
|
|
|
13360644 |
|
|
|
|
PCT/US2010/037286 |
Jun 3, 2010 |
|
|
|
13307681 |
|
|
|
|
61217653 |
Jun 3, 2009 |
|
|
|
61240934 |
Sep 9, 2009 |
|
|
|
61266840 |
Dec 4, 2009 |
|
|
|
61285468 |
Dec 10, 2009 |
|
|
|
Current U.S.
Class: |
428/473 ; 29/825;
428/540 |
Current CPC
Class: |
D06M 15/63 20130101;
D06N 2201/06 20130101; G06F 2203/04101 20130101; D06M 23/08
20130101; C14C 3/06 20130101; Y10T 428/268 20150115; G06F 3/041
20130101; D06N 3/0061 20130101; D06N 2203/068 20130101; G06F 3/044
20130101; A41D 19/0006 20130101; D06N 3/0063 20130101; C14C 13/02
20130101; D06M 15/37 20130101; C14C 11/006 20130101; D06M 11/83
20130101; Y10T 428/4935 20150401; D06N 3/0056 20130101; C14C 9/02
20130101; D06M 11/74 20130101; Y10T 29/49117 20150115; G06F 3/0354
20130101; G06F 2203/0331 20130101; Y10T 428/249982 20150401; C09D
175/04 20130101; G06F 3/014 20130101; C09D 175/04 20130101; C08L
2666/20 20130101 |
Class at
Publication: |
428/473 ; 29/825;
428/540 |
International
Class: |
H01B 1/20 20060101
H01B001/20; H01R 43/00 20060101 H01R043/00; B32B 9/02 20060101
B32B009/02 |
Claims
1. An electrically-conductive modified material adapted for
interacting with a touch screen device, the modified material
comprising: a leather material, wherein the leather material is a
colloid material comprising a plurality of fibers dispersed
therewithin; an electrically conductive agent; and a binder
material; wherein at least a portion of the leather material is
impregnated with the electrically conductive agent and the binder
at a sufficient concentration to provide electrical conductivity in
the modified material; wherein the modified material has a volume
resistivity of less than about 1.0.times.10.sup.6 ohm-cm; wherein
the modified material, when formed into an object for interacting
with the touch screen device, has an effective capacitance of
greater than 10.0 pico-Farads (pF); and wherein the electrical
conductivity and the capacitance of the modified material make the
modified material capable of capacitively coupling to the touch
screen device.
2. The modified material of claim 1, wherein the modified material
comprises at least about 30% electrically conductive agent.
3. The modified material of claim 1, wherein the electrically
conductive agent is selected from the group consisting of: carbon
black, carbon nanotubes, graphite, PEDOT, silver, copper, gold,
nickel, aluminum, indium, zinc, tin, and combinations thereof.
4. The modified material of claim 1, wherein the electrically
conductive agent is loaded onto the plurality of fibers located
within the leather material through ionic bonding.
5. The modified material of claim 1, wherein the plurality of
fibers located within the leather material are collagen fibers.
6. The modified material of claim 1, wherein at least some of the
plurality of fibers in the leather material comprise a fiber
chain.
7. The modified material of claim 6, wherein the fiber chain has a
length of at least 100 nanometers.
8. The modified material of claim 7, wherein the at least some of
the plurality of fibers comprising the fiber chain overlap in such
a manner that the modified material can withstand tensile,
compressive, or shear strains without suffering significant loss of
the electrical conductivity in the modified material.
9. The modified material of claim 1, wherein the electrically
conductive agent is substantially homogenously dispersed or
suspended within the binder material.
10. The modified material of claim 1, wherein the electrically
conductive agent is cured into the modified material.
11. The modified material of claim 1, wherein the modified material
retains a volume resistivity of less than about 1.0.times.10.sup.5
ohm-cm after the modified material is in its finished form.
12. The modified material of claim 1, wherein the modified material
further comprises a base coat, a color coat, a midcoat, and/or a
finishing coat.
13. The modified material of claim 1, wherein the modified material
further comprises aqueous polyether polyurethanes, solvent-borne
polyether/polyester, aqueous acrylics, styrene butadiene rubber,
nitrocellulose lacquers and water emulsions, cellulose acetate
butyrate lacquers and water emulsions, shellac, epoxy, polyvinyl
chloride, oils, waxes, silicones, and/or combinations thereof.
14. A method for modifying a leather material for interacting with
a touch screen device, the method comprising: providing a leather
material, wherein the leather material is a colloid material
comprising a plurality of fibers dispersed therewithin toggling the
leather material to a percentage of its maximum stretch; loading an
electrically conductive agent onto the plurality of fibers located
within the leather material; binding the electrically conductive
agent to the plurality of fibers located within the leather
material with a binder material; and curing the leather material,
the electrically conductive agent, and the binder material
together; wherein the modified material has a volume resistivity of
less than about 1.0.times.10.sup.6 ohm-cm; wherein the modified
material, when formed into an object for interacting with the touch
screen device, has an effective capacitance of greater than 10.0
pico-Farads (pF); and wherein the electrical conductivity and the
capacitance of the modified material make the modified material
capable of capacitively coupling to the touch screen device.
15. The method of claim 14, wherein the electrically conductive
agent has a positive charge or is non-ionic.
16. The method of claim 14, wherein the electrically conductive
agent is selected from the group consisting of: carbon black,
carbon nanotubes, graphite, PEDOT, silver, copper, gold, nickel,
aluminum, indium, zinc, tin, and combinations thereof.
17. The method of claim 14, wherein the plurality of fibers located
within the leather material have a negative charge.
18. The method of claim 14, wherein at least some of the plurality
of fibers disposed within the leather material comprise a fiber
chain.
19. The method of claim 18, wherein the fiber chain has a length of
at least 100 nanometers.
20. The method of claim 19, wherein the at least some of the
plurality of fibers comprising the fiber chain overlap in such a
manner that the modified material can withstand tensile,
compressive, or shear strains without suffering significant loss of
the electrical conductivity in the modified material.
21. The method of claim 14, further comprising transporting the
electrically conductive agent to the plurality of fibers located
within the leather material in a mixture of water and fat.
22. The method of claim 21, wherein the fat has a positive
charge.
23. The method of claim 14, further comprising bonding the
electrically conductive agent to the plurality of fibers through
ionic bonding.
24. The method of claim 14, further comprising tumbling the
modified material.
25. The method of claim 14, wherein the modified material retains a
volume resistivity of less than about 1.0.times.10.sup.5 ohm-cm
after the modified material is in its finished form.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation application of and claims
priority to U.S. patent application Ser. No. 13/307,681 which is a
continuation of PCT/US2010/037286 filed Jun. 3, 2010 that claims
the benefit of U.S. Patent Application Ser. No. 61/217,653, filed
Jun. 3, 2009, 61/240,934, filed Sep. 9, 2009, 61/266,840, filed
Dec. 4, 2009, and 61/285,468, filed Dec. 10, 2009, the disclosures
of which are incorporated herein by reference in their
entirety.
FIELD OF THE EMBODIMENTS
[0002] The described embodiments relate generally to a modified
material that is capable of operating a capacitive touch screen.
The material is impregnated with a composition comprising either a
metallic or a non-metallic conductive agent and a binder. More
particularly, the described embodiments relate to a conductive
glove or a glove that is capable of coupling to a capacitive touch
screen.
BACKGROUND
[0003] In recent years the development and manufacture of
electronic devices using a touch screen as the human input
interface has grown exponentially. Multi-touch mobile phones and
handheld devices are becoming ever popular. The new multi-touch
capacitive touch screen is quickly becoming the dominant type of
technology used by manufacturers of these devices, as can be seen
with the success of Apple Computer's iPhone, iTouch, and iPad. Many
other manufacturers have also adopted the use of multi-touch
capacitive touch screens as to enable human interface without need
of a stylus, keyboard or mouse. Touch screens also play a prominent
role in the design of digital appliances such as the personal
digital assistant (PDA), satellite navigation devices, mobile
phones, video games, automatic teller machines (ATMs) and even
light switches. However, the user cannot interface with these
multi-touch devices, as intended, when the user of the device is
wearing gloves or is otherwise unable to touch the screen with
their skin. This can particularly be a problem in, for example,
northern or southern hemisphere countries when the weather is
colder. However, even for short periods of cold weather, like
during skiing, the operation of touch mobile devices is a problem.
Additionally, certain occupations require or suggest the use of
gloves to protect the hands from injuries, such as contractors,
product delivery drivers, military and public safety personnel.
There are also certain transportation and recreational activities
where the use of gloves might be used, such as, golfers, motorcycle
riders and gardeners, who desire to operate their touch
devices.
[0004] A popular form of the touch device includes a touch screen
which operates in a capacitive mode. For the capacitive system, a
layer that stores electrical charge is placed on the glass panel of
the monitor of the touch screen devices. This is a form of
capacitive coupling between the user and the capacitive touch
screen. This decrease is measured by circuits located at each
corner of the monitor. A processor of the touch screen device
calculates, from the relative differences in charge at each corner,
exactly where the touch event took place and then relays that
information to the touch-screen driver software.
[0005] The problem surrounds the fact that capacitive touch screens
rely upon an electrical response (transfer of charge or capacitive
coupling) from or to the user's body. Gloves and prosthetic
devices, unsurprisingly, prevent the electrical charge from passing
through to the screen. Therefore, one is required to remove a glove
whenever activating the device, like making a phone call, sending a
text a message, checking email, or operating any other touch screen
device.
[0006] There is a need for a material that provides a user with the
typical benefits provided by gloves, but additionally allows the
user to operate a touch-screen device without having to remove the
glove or otherwise put their skin in contact with the touch screen.
More particularly to enable the material, itself, to capacitively
couple with touch screen devices by use of an electrostatic
discharge enabling interaction with such devices without the need
of human skin contact for such capacitive coupling. Such a material
would allow someone who might have lost a finger, hand or limb and
has a prosthetic in its place to use touch screen devices as modern
prosthetics are not designed to enable capacitive coupling to these
capacitive touch screens.
[0007] Various attempts have been made to produce hand protection
that allows interaction of such devices without removing the
gloves. None of these solutions provide sufficient protection from
chemicals, weather or other potentially harmful situations, nor
allow use of the ten finger gesturing capabilities of the newer
touch screens.
[0008] Accordingly, there is a need for a new type of performance
leather that replicates the human touch, without the actually need
to capacitively couple to the human body, in order to enable the
use of these devices without having to remove the glove.
SUMMARY
[0009] In order to properly operate a capacitive touch screen
device with gloves on or without the ability to contact human skin
and without the use of a device, such as a stylus or other
embodiment specifically created for this purpose, the glove or
other material must provide enough electrical capacity to operate
the touch screen. Materials of this invention provide the requisite
electrical capacity to perform in such a manner, thereby allowing
for operation of the touch screen absent human conductive coupling
to the device.
[0010] In one embodiment, the invention is directed to a modified
material comprising a material where at least a portion of which is
impregnated with a composition comprising a non-metallic
electrically conductive agent and a binder at a sufficient
concentration of the conductive agent to provide electrical
conductivity in that portion of the impregnated material. In
another embodiment, the material is impregnated in at least a
portion thereof with a metallic electrically conductive agent. In
another embodiment, the material is textile, leather, non-woven
material, or a leather-like material. In another embodiment, the
material has a volume resistivity of less than about
1.0.times.10.sup.6 Ohm-cm or less than about 1.0.times.10.sup.5
Ohm-cm, or less than about 1.0.times.10.sup.4 Ohm-cm, or less than
about 1.0.times.10.sup.3 Ohm-cm or less than about
1.0.times.10.sup.2 Ohm-cm.
[0011] The invention is also directed to a method of operating a
capacitive touch screen by placing the modified material of the
invention in proximity to the touch screen in a manner that allows
for operation of the touch screen.
[0012] In one embodiment, a glove comprises the modified material
described above. In another embodiment, a user wearing the glove
may operate a capacitive touch screen. In some embodiments, the
glove is comprised of the modified material such that the user can
take advantage of "Ten Touch" touch screen devices, which utilize
all ten fingers being in contact with the screen at the same time
in order to solicit a specific response from the multi-touch touch
screen devices.
[0013] Also provided is a leather product, either black or colored,
having a volume resistivity of less than about 1.0.times.10.sup.6
Ohm-cm. In some embodiments, the volume resistivity is from about
1.0.times.10.sup.3 Ohm-cm to about 1.0.times.10.sup.4 Ohm-cm.
[0014] One additional embodiment includes a conductive glove. The
conductive glove optionally includes a liner, wherein the liner is
less than 1 mm thick and/or has a volume resistivity of less than
1.0.times.10.sup.6 Ohm-cm. The conductive glove further includes an
electrically conductive thermal insulator layer adjacent to the
liner, and optionally an outer shell adjacent to the electrically
conductive insulating layer, wherein the outer shell is optionally
less than 1 mm thick and/or has a volume resistivity of less than
1.0.times.10.sup.6 Ohm-cm.
[0015] Another embodiment includes a further iteration of a
conductive glove. In this iteration, the conductive glove includes
an outer shell. The outer shell includes at least one conductive
channel, wherein at least one the conductive channel extends from
an inner surface of the outer shell to an outer surface of the
outer shell, and the conductive channel has a volume resistivity of
less than 1.0.times.10.sup.6 Ohm-cm.
[0016] In one embodiment, at least one the fingers or the pad of
the fingers of the glove are impregnated with a non-metallic or
metallic electrically conductive agent and a binder at a sufficient
concentration of the conductive agent to provide electrical
conductivity in to the fingers of the glove.
[0017] In another embodiment, the entirety of the glove is
impregnated with a non-metallic or metallic electrically conductive
agent and a binder at a sufficient concentration of the conductive
agent to provide electrical conductivity in to the entirety of the
glove.
[0018] Other aspects and advantages of the described embodiments
will become apparent from the following detailed description, taken
in conjunction with the accompanying drawings, illustrating by way
of example the principles of the described embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 shows a cross-section of an embodiment of an
electrically conductive glove.
[0020] FIG. 2 shows a cross-section of another embodiment of an
electrically conductive glove.
[0021] FIG. 3 shows a cross-section of another embodiment of an
electrically conductive glove.
[0022] FIG. 4 shows a cross-section of another embodiment of an
electrically conductive glove.
DETAILED DESCRIPTION
[0023] Prior to discussing the invention, all numerical
designations, e.g., pH, temperature, time, concentration, and
molecular weight, including ranges, are approximations which are
varied (+) or (-) by increments of 5%. It is to be understood,
although not always explicitly stated that all numerical
designations are preceded by the term "about". It also is to be
understood, although not always explicitly stated, that the
reagents described herein are merely exemplary and that equivalents
of such are known in the art.
[0024] It must be noted that as used herein, and in the appended
claims, the singular forms "a," "an," and "the" include plural
references unless the context clearly dictates otherwise.
[0025] Unless defined otherwise, all technical and scientific terms
used herein have the same meanings as commonly understood by one of
ordinary skill in the art to which this invention belongs. Although
any methods and materials similar or equivalent to those described
herein can be used in the practice or testing of the present
invention, the preferred methods, devices, and materials are now
described. All publications cited herein are incorporated herein by
reference in their entirety for the purpose of describing and
disclosing the methodologies, reagents, and tools reported in the
publications that might be used in connection with the invention.
Nothing herein is to be construed as an admission that the
invention is not entitled to antedate such disclosure by virtue of
prior invention.
[0026] As used herein, the term "comprising" is intended to mean
that the compositions and methods include the recited elements, but
do not exclude others. "Consisting essentially of" when used to
define compositions and methods, shall mean excluding other
elements of any essential significance to the combination for the
intended use. Thus, a composition consisting essentially of the
elements as defined herein would not exclude trace contaminants
from the isolation and purification methods of the components of
the compositions disclosed herein. "Consisting of" shall mean
excluding more than trace elements of other ingredients of the
compositions of this invention. Embodiments defined by each of
these transition terms are within the scope of this invention.
Materials
[0027] The invention is directed to, in part, a modified material
comprising a material where at least a portion of which is
impregnated with a composition comprising a non-metallic
electrically conductive agent and a binder at a sufficient
concentration to provide electrical conductivity in the impregnated
material. What is meant by the term "impregnate" is that the
material is somehow filled or infused with the composition. In some
embodiments, the material is coated with the conductive agent
without the use of an adhesive layer. In other embodiments, the
composition fills voids or interstices of the material. This can be
accomplished in a variety of ways, including but not limited to
spraying, roll coating, screen printing, brushing, sponging,
dipping, drying, curing, soaking, rinsing, or combinations of a
variety of treatments and the like. For example, the composition
may be applied to a material by spraying and then drying the
material with or without heat. This is more thoroughly described in
the next section.
[0028] It is contemplated that the materials of the invention may
include, but are not limited to, textiles, leathers, non-woven
materials, and a leather-like materials. It is contemplated that
the materials of the invention comprise some voids or interstices
to allow for effective impregnation of the conductive agents. These
materials may include, but are not limited to, leather, faux
leather, suede, faux suede, polymer, wool, cotton, fur, nylon,
fleece (including microfleece), fabric, cloth, woven and knitted
materials, polyester, nylon, synthetic fabrics, rubber, latex,
neoprene and the like.
[0029] As used herein the term "conductive agent," also referred to
herein as "electrically conductive" filler material, refers to an
agent that is electrically conductive. In some embodiments, the
agent is biocompatible, meaning it is compatible with human tissue.
In certain embodiments, the conductive agent comprises conductive
particles and/or conductive fibers. The "non-metallic conductive
agents" include, but are not limited to, carbon black, carbon
nanotubes, graphite, PEDOT, and combinations thereof. In certain
embodiments, the conductive agent comprises carbon fiber chains
with at least some of the carbon fiber chains having a length of
greater than 100 nanometers. In other embodiments, the agent is
long chain carbon black.
[0030] The non-metallic conductive agent may also be a polymer.
Representative polymers include poly(acetylene)s, poly(pyrrole)s,
poly(thiophene)s, polyanilines, polythiophenes, poly(p-phenylene
sulfide), and poly(para-phenylene vinylene)s (PPV), polyindole,
polypyrene, polycarbazole, polyazulene, polyazepine,
poly(fluorene)s, and polynaphthalene and combinations thereof.
[0031] The term "metallic conductive agents" refers to a variety of
conductive metals. Those metals include silver, copper, gold,
nickel, aluminum, indium, zinc, tin, tantalum, magnesium, sodium,
beryllium, barium, cadmium, calcium, rubidium, cesium, lithium,
molybdenum, cobalt, uranium, chromium, manganese, iron, platinum,
tungsten, osmium, titanium, iridium, ruthenium, nickel, rhodium,
palladium, steel, thallium, lead, niobium, vanadium, arsenic,
antimony, mercury, bismuth, tellurium and combinations or alloys
thereof. In certain embodiments, the metallic agent may be selected
from the group consisting of silver, copper, gold, nickel,
aluminum, indium, zinc, tin, and combinations or alloys
thereof.
[0032] Whether employing a metallic or non-metallic conductive
agent, the conductive agent may serve as a coating to another
particle or fiber. For example, silver-coated glass beads and
silver-coated fiberglass are useful in materials of the invention.
Further, it is also contemplated that a combination of conductive
agents may be used. For example, silver-coated glass beads can be
used in conjunction with carbon black.
[0033] The amount of conductive agent required can be readily
determined by one of skill in the art based on the conductivity of
the agent selected. For example, it is contemplated that for some
conductive agents, the modified material will be comprised of at
least about 30% (w/w) of conductive agent. For example, it is
contemplated that for some conductive agents, the modified material
will be comprised of at least about 5% (w/w) of conductive agent.
When selecting the amount of conductive agent, the desired
conductivity should be considered. For example, the modified
materials of the invention have a volume resistivity of less than
about 1.0.times.10.sup.6 ohm-cm or less than about
3.0.times.10.sup.5 ohm-cm or less than about 1.0.times.10.sup.5
ohm-cm or less than about 1.0.times.10.sup.4 ohm-cm or less than
about 1.0.times.10.sup.3 ohm-cm. Further, the modified material
retains similar volume resistivity after any pre-commercialization
treatments, such as stretching, bending, deforming and the like. It
is also contemplated that the materials of the invention retain
their conductivity after being used for about 1 month or longer. It
is contemplated that the modified material of the invention retains
its conductivity for at least about 6 months or at least a year or
longer.
[0034] In other embodiments, the conductive agent is substantially
homogeneously dispersed or suspended with a binder. Any number of
suitable binders will suffice and can be readily determined by one
of skill in the art based on material on which it is being applied.
The composition may also optionally comprise aqueous polyether
polyurethanes, solvent-borne polyether/polyester, aqueous acrylics,
styrene butadiene rubber, nitrocellulose lacquers and water
emulsions, cellulose acetate butyrate lacquers and water emulsions,
shellac, epoxy, polyvinyl chloride, oils, waxes, silicones, and/or
combinations thereof. Additional components include dyes and
pigments, ionic additives, pH balancers, fastness agents, water,
adhesion promoters, bonding agents, aromatic polyurethanes,
aliphatic polyurethanes, carriers including resins, binders,
cross-linking agents, acrylics, UV protective additives, feel
enhancers, and the like.
[0035] In certain embodiments the material optionally has any
number of additional coats, such as for example, a base coat, a
midcoat, a color coat, and a top or finishing coat. The additional
components may be in any number of additional coats just described.
Further, the composition comprising the conductive agent can be
applied in a base coat, a midcoat, a color coat, and/or the top
coat. In one embodiment, the top coat comprises cellulose acetate
butyrate. In one embodiment, the base coat does not contain an
adhesive material. In another embodiment, the base coat comprises
carbon black as the conductive agent.
[0036] One embodiment of the present invention is directed to a
leather which has been impregnated with a capacitive material, such
as carbon black, that allows the flow of electrons in the form of
an electrostatic discharge in order to operate touch screen
devices.
[0037] In one embodiment, the present invention provides a process
for tanning leather for use in gloves or garments with the unique
ability to discharge static electricity, which can be harmful to
electronic devices.
[0038] Another embodiment of the present invention is directed to a
tanned leather which consists of a collagen based internal fiber
matrix, made up of the grain, corium-grain junction, the corium and
a plurality of capacitive particles creating a conductive network
throughout the material, or portions or layers thereof. The
capacitive particles, are embedded within the fiber matrix and/or
are on the surface of the leather, providing a conductive network
throughout the material. In sufficient amount, the capacitive
material will create an electrostatic discharge (ESD), comparable
to that of the human body, enabling the leather to drive the
software on capacitive or other types of touch screen devices
without the need for coupling to human skin/body.
[0039] Another embodiment of the present invention is directed to
leather products formed of such leather, such as garments, shoes,
gloves, wallets, purses, furniture, shelters or other such
applications where the end product would be real leather, with the
unique performance ability to discharge static electricity or
create an electromagnetic interference (EMI), for blocking certain
bands of radio transmissions and absorption of radio
frequencies.
[0040] A further embodiment of the present invention is directed to
a method of impregnating a material having an internal or external
fiber matrices for the purpose of providing additional performance
capabilities not normally found in such substrates as currently
processed. The methods comprise the steps of placing the material
in a container, adding a tanning agent to the container, adding a
plurality of capacitive particles with a liquid to form a
suspension, and adding the suspension to the container and
agitating the contents of the container until the capacitive
particles are embedded throughout the fiber matrices. A sufficient
enough amount of the capacitive material is embedded so that the
particles create a pathway for the electrons to discharge into
providing the capacitive coupling without the need for human skin
contact. In the method, the material can be either raw skins or
tanned leather.
[0041] Yet a further embodiment of the present invention is
directed to a method of impregnating a material through the use of
a finishing system. The finishing system could be any of, including
combinations of a water or solvent based leather finishing system,
dye coat, or other such systems, which carry the conductive
particles onto and/or into the fiber matrices, or coat the surface
of the leather, in a high enough concentration, to create a
conductive network along the surface and/or through the volume of
the leather, to create a capacitive coupling, electrostatic
discharge, or electromagnetic interference.
Leather Materials
[0042] The invention is also directed to leather products,
including, but not limited to, black leather products and colored
leather products that are electrically conductive. The term
"colored leather" refers to white, red, magenta, cyan, black,
yellow and any combinations thereof. The leather products or
materials of the invention may be created in the following method.
For lighter colors, such as white leather, it is contemplated that
a capacitive titanium dioxide material can be used, such as
fluorine or zinc-doped titanium dioxide, such as that disclosed in
U.S. Pat. No. 5,597,515 (Kauffman, et al., issued Jan. 28, 1997)
which is herein incorporated by reference in its entirety.
[0043] A tanned leather (crust) is obtained. This leather may be
tanned with conventional tanning agents, including chromium and or
aluminum salts, vegetable based tannins, etc. The tanned leather is
then colored by tumbling in a tumbling drum, using one or more of
the following in solution: dyes, ionic additives, pH balancers,
fastness agents, and/or water.
[0044] Once the coloring process is complete, the leather is
toggled. Toggling involves stretching the leather while wet to some
percentage of the maximum stretch to which the leather can accept.
For the leather materials of the current invention, the leathers
are toggled to between 25% and 75% of the maximum toggling, and
preferably to 50% of the maximum toggling. While stretched
(toggled), the leather material is then dried, after which the
dried leather is removed from the stretching fixture.
[0045] The leather material is then optionally coated with a base
coat. Said base coat comprises one or more of the following: (1)
electrically conductive filler material (for example carbon black
particles such as long chain carbon black particles, silver
particles, silver coated silicates, silver coated copper particles,
copper particles, nickel, tin, or aluminum particles or coated
particles, conductive or coated fibers or particles, etc.); (2)
adhesion promoters; (3) bonding agents; (4) paints or other
coloring agents; (5) aromatic polyurethane; (6) aliphatic
polyurethane; (7) other carriers, including but not limited to
resins, binders, cross linking agents, acrylics, etc.
[0046] This coating process is typically accomplished by spraying
said coating onto the leather surface, and said additives and
binders cause said base coat to bond to said leather material. Said
long chain carbon black forms long chain-like electrically
conductive pathways within the coating layer and the surface of the
porous base leather material in such a manner that said coated
leather material maintains its conductivity and capacitance when
said leather material is bent, stretched, or otherwise deformed.
The coating is then cured (dried) either under heat or air dried
without heat. The resulting coating is both electrically conductive
(with an electrical conductivity below about 1.0.times.10.sup.6
Ohm-cm and chemically and/or mechanically bonded to the leather
material.
[0047] A mid-coat optionally is then applied, comprising one or
more of the following: (1) aromatic polyurethane; (2) aliphatic
polyurethane; (3) conductive fillers and/or (4) water.
[0048] This mid-coat is cured with or without heat. Said mid-coat
is applied with electrically conductive fillers in such a
concentration and in such a manner that said conductive fillers
form conductive pillar structures that bridge the thickness of said
mid-coat, providing electrically conductive continuity between the
surface of said mid-coat and said base coat.
[0049] A finish, or top, coat is then applied to the leather
material to further condition the material by adding abrasion
resistance, water proofing, fire resistance, look and feel
enhancement etc. A suitable water-proofing agent to be used
includes TFL-DRYWALK.RTM. (1% by dry weight). A suitable fire
resistance agent to be used includes bromine salts, such as
FLAMEPROOF fire retardants (FLAMEPROOF 1694, Apexical, Inc.
Spartenburg, S.C.). It is contemplated that the modified material
can be formulated with such fire retardants such that the material
can withstand temperatures of up to about 1400 degrees Fahrenheit
or about 1500 degrees Fahrenheit or greater. Such reagents can be
added to the leather or fabric during the tanning, coloring and/or
finishing process. The finish coating may be comprised of one or
more of the following constituents: polyurethanes; acrylics;
binders; look and feel enhancers; waxes; silicones; electrically
conductive fillers; UV protective additives; penetrating polymers,
and/or water.
[0050] This coating may be applied very lightly to ensure
electrical conductivity with and/or electrical capacitive coupling
to the base coating. Alternately, the finish coating may be loaded
with conductive fillers in such a manner that said electrically
conductive fillers form electrically conductive pillars, or
electrically conductive pathways, between the outer surface of said
finish coat and said electrically conductive mid- and base
coatings.
[0051] The leather material then undergoes a final curing step in
which the finish coating is cured, typically with heat, but
alternately without heat. After the final coating the leather is
milled, by tumbling the leather material in a tumbler to restore
flexibility, softness, and/or suppleness.
[0052] Although the above method is specifically used for leather
materials, the coatings and coating processes may be used on other
materials such as artificial leathers, and woven or non-woven
fabric textiles such as cotton, polyester fiber, nylon fiber, vinyl
fiber, silk, wool, lyocell, or other natural or artificial
fibers.
[0053] The above described method of the invention produces a
leather or other material that is highly conductive, with a volume
resistivity below about 1.0.times.10.sup.6 Ohm-cm, and/or has a
capacitance approximately equivalent to that of the human body.
This capacitance may be as low as 10 pico-Farads (pF), or higher,
such as about 50 pF, or about 100 pF, or about 200 pF, or about 300
pF, or about 400 pF, or about 500 pF with respect to a distant
ground. In some embodiments, the capacitance is between about 10 pF
and about 50 pF, or between about 10 pF and about 500 pF, or
between about 50 pF and about 500 pF.
[0054] The electrically conductive and capacitive materials of the
invention may be then used in conventional or non-conventional
methods to produce garments and various products, such as gloves,
jackets, shirts, pants, coats, body suits, wet suits, boots, socks,
hats, other clothing items, backpacks, belts, straps, bags,
parachutes, upholstery, bedding, curtains, carpeting, computer
bags, travel bags, duffel bags, etc.
[0055] The finished conductive and/or capacitive leather material
of the invention exhibits several functional, morphological, and
structural characteristics. The first of said functional
characteristics is said leather material's low electrical
resistivity, as measured between two points on the coated surface
of said leather material. The electrical resistivity of said coated
leather material may be expressed as a surface resistivity or as a
volume resistivity. The surface resistivity of the leather material
of the invention is less than 1.0.times.10.sup.6 Ohm/square, and
the volume resistivity is less than 1.0.times.10.sup.6 Ohm-cm.
[0056] The next of said functional characteristics is said leather
material's high capacitance with respect to a distant ground. The
capacitance of said electrically capacitive leather material is
greater than 10.0 pF.
[0057] The next of said functional characteristics is said leather
material's ability to maintain said low electrical resistivity and
high capacitance when said leather material is stretched, twisted,
bent, wrinkled, abraded, etc., without significant degradation to
said electrical properties.
[0058] Without being limited to any one theory, it is contemplated
that the above-mentioned functional characteristics are a result of
one or more of the following morphological and structural
characteristics. The first of said morphological and structural
characteristics is penetration of the base coat into the porous
and/or fibrous surface of said leather material. During the coating
process, one or more solvents, carriers, surfactants, polymers, or
other liquids carries the electrically conductive particles and/or
fibers into the porous surface of said leather material. During the
ensuing curing process, one or more of said solvents, carriers,
surfactants, polymers or other liquids evaporates and or cross
links, and/or cures, leaving the interstitial porous structure of
said leather material substantially filled with said electrically
conductive particle and/or fiber material. Additionally, one or
more polymers, waxes, fillers, binders, adhesives, or other
materials may remain with said electrically conductive material in
said porous or fibrous structure of said leather material after
curing. This interstitially penetrated material combination forms a
matrix of said electrically conductive materials, said binders,
adhesives, polymers, waxes, etc. that is electrically conductive,
possesses a capacitance with respect to a distant ground, and not
easily removed from the surface of said leather material.
[0059] It is contemplated that the base and/or the mid coats
provide this matrix which penetrates the leather grain or flesh
such that the electrically conductive materials are sufficiently
dispersed throughout the thickness of the leather. This dispersion
allows the leather to retain its capacitive function in the event
that the leather is worn down or damaged in some way.
[0060] The next of said morphological and structural
characteristics is the existence of a dense layer of electrically
conductive material, such as carbon black, on the surface of the
coated base layer of said leather material. The electrically
conductive material in said base layer may be of sufficient
concentration, buoyancy, surface tension, or other property to
allow said electrically conductive material to form a surface layer
during the spray coating and/or curing process. Said surface layer
acts as a highly electrically conductive layer on said leather
material, enabling both low electrical resistivity and high
electrical capacitance.
[0061] The next of said morphological and structural
characteristics is the existence of pillar like structures of
conductive particles and/or fibers within one or more of the
coating layers of said electrically conductive and capacitive
leather material. During the coating and/or curing process, said
electrically conductive particles and/or fibers in said coating
form closely packed structures within said coating layer such that
electrical pathways are formed which span the thickness of said
coating, creating matrix of electrically conductive pathways from
the surface of said coating to the base of said coating. In this
manner said coating may contain a dielectric binder, such as
polyurethane, and a conductive filler, such as carbon black, and
maintain a very low electrical resistivity once said coating and
curing processes are complete.
[0062] The next of said morphological and structural
characteristics is the existence of electrically conductive fibers
and/or electrically conductive particles, within one or more of the
coating layers of said finished leather material. Said long fibers
(for example long chain carbon black, or silver coated polymer
fibers) form a structure within said coating layer or layers in
which said fibers and or particles overlap one another in such a
manner that said coating may undergo tensile, compressive, or shear
strains (deformations) without suffering significant loss of
electrical conductivity. As the leather material and the coating
layer are deformed, said fibers and/or particles may experience
small amounts of relative displacement yet maintain sufficient
electrical conductivity so that said overall leather material
continues to maintain the desired electrical conductivity and
capacitance.
[0063] In one exemplary embodiment of the invention, described
here, a black colored leather material is produced with a volume
resistivity of between 1.0.times.10.sup.3 and 1.0.times.10.sup.4
Ohm-cm, and a capacitance relative to a distant ground of between
50 pF and 500 pF. A tanned cattle leather is taken, having been
tanned in a conventional leather tanning process using chromium
salts. Said tanned leather is then colored in tumbling drum using a
solution of carbon black leather pigment, water, ionic additives,
and pH balancers. Other chrome tanning processes or even other
basic mineral or vegetable tanning processes can be utilized as the
preliminary tanning method. Chromium sulfate, zirconium, aluminum
and vegetable tannages may also be utilized with the present
invention.
[0064] Said leather is then removed from the tumbling drum and
toggled to 50% of its maximum stretch, or toggle. Said toggled
leather is dried while in this toggled state using a heater to
accelerate the drying process.
[0065] Said toggled and dried leather is then removed from the
toggling fixture and a base coat is applied, said base coat
comprising:
TABLE-US-00001 160 parts aliphatic polyurethane and optionally a
binder 160 parts water 60 parts Butyl Cellosolve Acetate 72 parts
long chain conductive carbon black particles 84 parts carbon black
based leather pigment
[0066] Said base coat is sprayed onto the surface of said leather
in such a manner as to uniformly and thoroughly coat said leather
material. Said coated leather material is then cured, using heat to
accelerate the curing process.
[0067] A mid-coat is then applied to said coated leather, said
mid-coat comprising:
TABLE-US-00002 1 part Aliphatic Polyurethane optionally with binder
1 part Aromatic Polyurethane optionally with binder 1 part
water.
[0068] Said mid-coat is applied to said coated leather in a spray
coating process to evenly and thoroughly coat said leather
material. Said leather with said mid-coat is cured with heat to
accelerate the curing process.
[0069] A finish coat is then applied to said coated and cured
leather material, said finish coat comprising:
TABLE-US-00003 200 parts Cellulose Acetate Butyrate 100 parts water
18 parts Waxy feel enhancer
[0070] Said finish coat is applied to said coated leather material
in a spray coating process to evenly and thoroughly coat said
leather material. Said leather with said finish coat is cured with
heat to accelerate the curing process.
[0071] Finally, said coated leather is milled by tumbling said
coated and cured leather in a tumbler to restore flexibility and
suppleness to said leather material.
[0072] In a second exemplary embodiment of the invention, described
here, a red colored leather material is produced with a volume
resistivity of between 1.0.times.10.sup.1 and 1.0.times.10.sup.5
Ohm-cm, and a capacitance relative to a distant ground of between
50 pF and 500 pF. A tanned cattle leather is taken, having been
tanned in a conventional leather tanning process using chromium
salts. Said tanned leather is then colored in tumbling drum using a
solution of carbon black leather pigment, water, ionic additives,
and pH balancers.
[0073] Said leather is then removed from the tumbling drum and
toggled to 50% of its maximum stretch, or toggle. Said toggled
leather is dried while in this toggled state using a heater to
accelerate the drying process.
[0074] Said toggled and dried leather is then removed from the
toggling fixture and a base coat is applied, said base coat
comprising:
TABLE-US-00004 66.6 parts Aliphatic polyurethane optionally with a
binder 160 parts water 60 parts Butyl Cellosolve Acetate 3.33 parts
Ashbury 5303 long chain conductive carbon black 30 parts Silver
coated glass beads.
[0075] Said base coat is sprayed onto the surface of said leather
in such a manner as to uniformly and thoroughly coat said leather
material. Said coated leather material is then cured, using heat to
accelerate the curing process.
[0076] A color coat is then applied to said coated and cured
leather material, said color coat comprising:
TABLE-US-00005 10 parts Aliphatic Polyurethane and optionally a
binder 5 parts Red color pigment 10 parts Silver coated glass beads
1 part Long chain conductive carbon black 10 parts water.
[0077] Said color coat is applied to said coated leather in a spray
coating process to evenly and thoroughly coat said leather
material. Said leather with said color coat is cured with heat to
accelerate the curing process.
[0078] A mid-coat is then applied to said coated leather, said
mid-coat comprising:
TABLE-US-00006 10 parts Aliphatic Polyurethane optionally with
binders; 10 parts Aromatic Polyurethane optionally with binders; 10
parts Silver coated glass beads; 1 part Long chain conductive
carbon black; and 10 parts water.
[0079] Said mid-coat is applied to said coated leather in a spray
coating process to evenly and thoroughly coat said leather
material. Said leather with said mid-coat is cured with heat to
accelerate the curing process.
[0080] A finish coat is then applied to said coated and cured
leather material, said finish coat comprising:
TABLE-US-00007 200 parts Cellulose Acetate Butyrate 100 parts
Silver coated glass beads 10 parts Long chain conductive carbon
black 100 parts water 18 parts Waxy feel enhancer 10 parts UV
protective additive
[0081] Said finish coat is applied to said coated leather material
in a spray coating process to evenly and thoroughly coat said
leather material. Said leather with said finish coat is cured with
heat to accelerate the curing process.
[0082] Finally, said coated leather is optionally milled by
tumbling said coated and cured leather in a tumbler to restore
flexibility and suppleness to said leather material. Such material
is referred to herein as "finished", or being in "finished
form".
Other Materials
[0083] It is further contemplated that similar procedures could be
used on vinyl resins using standard vinyl manufacturing processes
which typically employ vinyl and plasticizers. The vinyl and
plasticizers are stirred together in a vat and then mixed with AZO
compound (having carbon and nitrogen) and heated to make a foam
with the consistency of pancake batter. Silver, copper, nickel
and/or carbon black power may then be added to the base polymer
along with other pigments. This slurry may then be poured onto an
appropriate backing sheet, such as felt, fleece (microfleece),
suede or a velvet-like napped surface to provide strength and
flexibility. This may then be put through a reverse roll coater
machine, heated in an oven until the vinyl resin absorbed the
plasticizers and started to set. Then the sheets may be run through
a printing press with plates that were designed to imprint the
texture or grain of leather into the vinyl material. If further
coloring were desired, additional sprays of colorants may be added
in a manner that does not affect the conductivity. In some
embodiments, the modified material is produced using yarn wherein
at least a portion of the yarn is capacitive yarn. In some
embodiments, the modified material which comprises capacitive yarn
is not further treated or coated with conductive material. In
another embodiment, the modified material which comprises
capacitive yarn is woven such that the material has a uniform
conductivity throughout the material.
[0084] Woven or knitted materials can be impregnated with a
conductive material, such as metal oxides, metal fibers or a
carbon-black based material. The impregnation step is such that the
conductive material is used to fabricate a bolt of capacitive
fabric. For example, the conductive fibers are blended with an
organic or inorganic material, such as cotton, nylon, polyester and
the like, to form a capacitive yarn. The capacitive yarn is then
woven or knit with a non-capacitive yarn which can be either an
organic or inorganic material, such as cotton, nylon, polyester and
the like, to form a capacitive fabric.
[0085] Suitable conductive materials to be used in the capacitive
yarn are Thunderon.RTM. (Static Faction, Inc.) which is an organic
fiber of copper sulfide chemically bonded to acrylic and nylon
fibers, SHIELDEX metalized yarns and conductive sewing threads
which are silver-based, and Resistat.RTM. (Jarden Applied
Materials) which is a nylon fiber with electrically conductive
carbon particles which become part of the structure of the fiber.
Ideally, with the conductive yarn would retain the strength and
flexibility of the organic or inorganic yarn material while
maintaining excellent conductivity.
[0086] In the woven or knitted capacitive fabric, the capacitive
yarn should account for at least about 0.6 to about 23% of the yarn
in the fabric and should result in a surface resistivity of at
least about 3.times.10.sup.5 Ohm/cm. This amount depends on the
type of conductive material used. For example, when a highly
conducive material, such as the silver-based yarn, is used the
amount of conductive yarn required would be less. However, when a
carbon-based yarn is used, a higher percentage may be required to
achieve the desired resistivity. For example, a capacitive material
can be made by weaving or knitting a bolt of fabric using 85%
non-capacitive thread (e.g. polyester) with 15% capacitive thread
(e.g. Resistat.RTM.). The capacitive thread would thus be uniformly
distributed throughout the conductive woven or knitted fabric.
Therefore, a garment such as a glove made from the above-described
conductive fabric would be capacitive throughout the garment.
Additionally, the conductive fabric as disclosed herein can be
laundered multiple times (i.e. more than 10 times, or more than 50
times, or more than 100 times) in a standard wash/dry cycle without
any observable depletion in the conductive properties.
[0087] The conductive fabric is designed to interact with touch
screen devices and can be used to make a garment such as a glove
for use with a touch screen device. However, the conductive
coupling of the touch screen is to the conductive material, not to
a hand or body part in contact with the conductive material. In
some embodiments, the glove will still operate the touch screen
device without a human hand inside the glove. Therefore, a glove
made from the conductive fabric as disclosed herein can be used by
an amputee.
[0088] In one embodiment, the modified material has a volume
resistivity of less than about 3.0.times.10.sup.5 Ohm-cm, or
alternatively, less than about 3.0.times.10.sup.6 Ohm-cm, or
alternatively, less than about 1.0.times.10.sup.6 Ohm-cm and/or a
surface resistivity of less than about 3.0.times.10.sup.5 Ohm-cm,
or alternatively, less than about 3.0.times.10.sup.6 Ohm-cm, or
alternatively, less than about 1.0.times.10.sup.6 Ohm-cm.
Glove Embodiments
[0089] The modified materials of the invention may be used in a
number of capacities as described above allowing a user to operate
a capacitive touch screen. Briefly stated, provided is a modified
material which comprises electrically conductive material and/or
chemical treatments, to enable a capacitive coupling to Capacitive
and Projected Capacitance Touch Screen devices and any other types
of touch screen devices, regardless of the touch screen technology
used. The modified material provides for either a projected
capacitance of the human body through the material to the
interface, or a direct capacitive coupling to the textile itself,
thereby not requiring human contact to operate the touch screens or
touch pads. The modified material can be fabricated into a
functional article of clothing, such as a glove or other item made
of a woven or knitted textile so as to increase the functionality
of the article of clothing or item made thereof. The conductive
material can create a bridge to PCT devices, wherein the conductive
material comprises integrated components, or chemical treatments
serving as a connection to the devices without the need for the
human body to create this capacitive coupling. As shown in the
drawings, the described embodiments of the modified material of the
invention are embodied in a conductive glove, wherein the
conductive glove allows a user of the conductive glove to operate a
touch screen device without removing the glove. The gloves of the
invention also provide a barrier from certain viruses, bacteria and
fungi that can easily be passed from interacting with previously
contaminated touch screen surfaces during interaction.
[0090] FIG. 1 shows a cross-section of an embodiment of an
electrically conductive glove. This embodiment includes a liner
110, a conductive insulator 120 and an outer shell 130. It is to be
understood that this is a cross-section of at least a portion of
the glove. That is, the entire glove is not required to be
fabricated as shown. In an application, the glove is worn by a user
of a touch screen device. An embodiment includes the portion of the
glove that the user uses to control the touch screen device being
fabricated as shown by the cross-section view of FIG. 1.
[0091] For an embodiment, the liner and outer shell being less than
2 mm or less than 1 mm or less than 0.5 mm thick and/or has a
volume resistivity of less than 1.0.times.10.sup.6 Ohm-cm and/or a
surface resistivity of less than 1.0.times.10.sup.6 Ohm-cm. When
any material has an electrical volume resistivity level of less
than 1.0.times.10.sup.6 Ohm-cm or a surface resistivity of less
than 1.0.times.10.sup.6 Ohm-cm it is widely considered to be in the
range of a conductive material. This is desirable because a
capacitive coupling with the touch screen is not possible if the
non-conductive liner and/or the outer shell is thicker than 0.5 mm
and not made of a conductive material.
[0092] In order to properly operate a capacitive touch screen
device with gloves on, without the use of a device, such as a
stylus or other embodiment specifically created for this purpose,
the glove itself must provide a capacitive coupling to the human
skin. This can be achieved by employing/using material as described
throughout that will not block the conductivity to the human skin
surface. When a fabric or material is used that is either too
thick, or has a volume resistivity of greater than
1.0.times.10.sup.6 Ohm-cm and/or a surface resistivity of greater
than 1.0.times.10.sup.6 Ohm-cm, the results are a material that is
electrically dissipative or insulative, not conductive and
therefore will not work for this application.
[0093] Various embodiments of the liner include at least one of
rayon, acetate, nylon, modacrylic, olefin, PLAY polyester, wool,
cotton, silk, acrylic, blends or any type of conductive woven fiber
blends, metallic fibers or fibers treated with copper, silver,
carbon black, carbon fiber, nickel, tin or other conductive
material with a thickness of less than 0.5 mm and/or a volume
surface resistivity of less than 1.0.times.10.sup.6 Ohm-cm and/or a
surface resistivity of less than 1.0.times.10.sup.6 Ohm-cm.
[0094] For an embodiment, the electrically conductive insulator
layer is located adjacent to the liner. Additionally, this
embodiment includes a resistance of the electrically conductive
insulator layer being less than 1.0.times.10.sup.6 Ohm-cm.
[0095] Embodiments of the electrically conductive thermal insulator
layer include a conductive foam, fiber, microfiber, microfilament,
plastic, metal, rubber or breathable thermal insulation with a
volume resistivity of less than 1.0.times.10.sup.6 Ohm-cm and/or a
surface resistivity of less than 1.0.times.10.sup.6 Ohm-cm.
[0096] Configurations of the conductive fiber, microfiber,
microfilament or breathable thermal, electrically conductive,
thermal insulation include materials made from different mixtures
of polymers, but primarily polyethylene terephthalate or a mixture
of polyethylene terephthalate and polypropylene. Other materials
may include polyethylene terephthalate, polyethylene isophthalate
copolymer and acrylic in combination with a conductive coating or
impregnated, embedded, compounded or plated conductive material
with a surface resistivity of less than 1.0.times.10.sup.6 Ohm-cm.
This can be accomplished by the use of a chemical reaction to bond
the molecules of carbon black, copper, silver, gold, nickel, tin or
other conductive metal substances, with the molecules of the host
fiber, or by plating or compounding any of these conductive
substances to the host fiber.
[0097] Other embodiments of the electrically conductive insulator
layer include a conductive foam, rubber, fiber, microfiber or
microfilament.
[0098] For an embodiment, the outer shell is formed adjacent to the
electrically conductive insulating layer. Additionally, this
embodiment includes the outer shell being less than 2 mm thick
and/or having a volume resistivity of less than 1.0.times.10.sup.6
Ohm-cm.
[0099] This is desirable because a capacitive coupling with the
touch screen is not possible if the non-conductive liner and/or the
outer shell is thicker than 0.5 mm and not made of a conductive
material.
[0100] In order to properly operate a capacitive touch screen
device with gloves on, without the use of a device, such as a
stylus or other embodiment specifically created for this purpose,
the glove itself must provide a capacitive coupling to the human
skin. This can be achieved by employing or using key types of
fabrics or other materials that will not block the conductivity to
the human skin surface. When a fabric or material is used that is
either too thick, or has a volumetric and/or surface resistivity of
greater than 1.0.times.10.sup.6 Ohm-cm, the results are a material
that is electrically dissipative or insulative, not conductive and
therefore will not work for this application.
[0101] Embodiments of the outer shell include rayon, acetate,
nylon, modacrylic, olefin, PLA, polyester, wool, cotton, silk,
acrylic, blends or any type of conductive woven fiber blends;
metallic fibers or fibers treated with copper, silver, carbon
black, carbon fiber, nickel, tin, other conductive material, animal
skin, vinyl, rubber, latex or silicone.
[0102] The embodiment of FIG. 1 can be fabricated by using a piece
of fabric made of wool, cotton or silk as a liner, for instance,
and securing it to a layer of electrically conductive thermally
insulative foam, or electrically conductive thermally insulative
microfiber insulation, for instance, and securing the insulation to
the outer shell. When all components of the glove meet the
specifications of both thickness and conductivity. By simply
pressing the skin firmly against the three layers of material will
produced the desired results of creating a capacitive coupling
through the dielectric and conductive surfaces to the touch screen
device and allows the user to use the device as if they were
touching the device with their bare skin.
[0103] FIG. 2 shows a cross-section of another embodiment of an
electrically conductive glove. This embodiment additionally
includes at least one conductive channel 210. Each of the
conductive channels 210 extends from an inner surface of the outer
shell 130 to an outer surface of the outer shell 130
[0104] Embodiments of the conductive channels 210 include
conductive material which may include resins, polymers, plastics,
rubbers, foams, fibers, metals, epoxies or adhesives. The
conductive channels provide enhanced conductivity between the skin
of the user's hand and the external surface of the glove as defined
by the outer surface of the outer shell 130.
[0105] One method of manufacturing the conductive channels includes
perforating the outer shell material (before forming the glove with
the conductive thermal insulator 120 and the liner 110) and filling
the perforations with a conductive gel, adhesive, resin, foam,
plastic, metal or fibrous substrate that meets the criteria of
being conductive. The number of perforations can number from one to
as many as desired in differing diameters, for the purpose of
covering the surface area adequately to allow the user to interact
with the device in the same manner they would if they were not
wearing gloves. The perforations can be spaced in specific patterns
for either aesthetic design or for materials that would normally be
weakened by holes in material to allow for the strength of the
material to not be compromised, provided that the function of
allowing conductive interaction between the user and the device are
not compromised.
[0106] FIG. 3 shows a cross-section of another embodiment of an
electrically conductive glove. This embodiment additionally
includes an outer conductive layer 310 adjacent to the outer
surface of the outer shell.
[0107] Embodiments of the outer conductive layer 310 include a base
coating of polyurethane, polyepoxide, paint, adhesive, sealant,
silicone, resins, polymers, plasticizers, vinyl compounds, metals
or plastics materials with an added electroconductive carbon,
silver, nickel, copper, tin, gold or other conductive metal or
alloy into the coating in high concentrations to achieve a volume
resistivity of less than 1.0.times.10.sup.6 Ohm-cm which may or may
not be specifically used to mimic the color, grain, texture and
feel of the outer surface of the outer shell.
[0108] An optional additional layer includes a color layer 320
adjacent the outer conductive layer 310. Embodiments of the color
layer are primarily aesthetic, and can be used to determine a glove
color, texture, grain or appearance.
[0109] A method of manufacturing the glove structure as shown in
FIG. 3 include, for example, an organic or inorganic fabric or
material that is designed for the comfort and warmth of the user
and functions as a method of wicking away moisture while allowing
conductance to take place. The materials may be made of cotton or
wool, for instance and meet the criteria of thickness and
conductance needed. Adjacent to the liner would be the electrically
conductive thermally insulative material; adjacent to the
insulative material would be the outer shell with the conductive
channels. Adjacent to the outer shell would be an outer conductive
layer, which may or may not be colored or textured to match the
outer surface of the outer shell.
[0110] FIG. 4 shows a cross-section of another embodiment of an
electrically conductive glove. This embodiment includes an outer
shell 130. As shown, the outer shell 130 includes at least one
conductive channel 210. Each of the conductive channels extend from
an inner surface of the outer shell 130 to an outer surface of the
outer shell 130. For an embodiment, each of the conductive channels
has a volume and/or surface resistivity of less than
1.0.times.10.sup.6 Ohm-cm.
[0111] Perforating the outer shell material (before forming the
glove with the conductive thermal insulator 120 and the liner 110)
and filling the perforations with a conductive gel, adhesive,
resin, foam, plastic, metal or fibrous substrate that meets the
criteria of being conductive. The number of perforations can number
from one to as many as desired in differing diameters, for the
purpose of covering the surface area adequately to allow the user
to interact with the device in the same manner they would if they
were not wearing gloves. The perforations can be spaced in specific
patterns for either aesthetic design or for materials that would
normally be weakened by holes in material to allow for the strength
of the material to not be compromised, provided that the function
of allowing conductive interaction between the user and the device
are not compromised.
[0112] Alternate embodiments can additionally include one or more
outer conductive layers 310 adjacent to the outer surface of the
outer shell 310. The addition of the conductive layer 310 provides
the ability to use less perforations, as few as one, that can be
strategically placed in inconspicuous areas of the glove and
provide a capacitive coupling anywhere on the treated surface of
the outer surface of the outer shell.
[0113] A method of manufacture for the outer conductive layer
includes, for example thin coat of conductive coating bonded to the
outer surface of the outer shell by means of spraying, painting,
heat/pressure bonding or by the use of a conductive adhesive
material.
[0114] Once the material is made to be conductive, the material is
said to be in "finished form".
[0115] Another embodiment includes a color layer 320. Embodiments
of the color layer 320 color layer are primarily aesthetic, and can
be used to determine a glove color, texture, grain or
appearance.
[0116] The color layer can be formed by use of a chemical bonding,
mechanical bonding or by spraying, painting, heat/pressure bonding
or by the use of a conductive adhesive or primer coating.
Additional Glove Embodiments
[0117] Additional embodiments of the glove are discussed below. In
one embodiment, the invention is directed to a conductive glove
comprising:
[0118] a liner, the liner being less than 2 mm thick and/or having
a resistance of less than 1.0.times.10.sup.6 Ohm-cm;
[0119] an electrically conductive insulator layer, with a
resistance of less than 1.0.times.10.sup.6 Ohm-cm, adjacent to the
liner; and
[0120] an outer shell adjacent to the electrically conductive
insulating layer, the outer shell being less than 2 mm thick and/or
having a resistance of less than 1.0.times.10.sup.6 Ohm-cm.
[0121] In one embodiment, the glove when worn by a user, at least a
portion of the liner physically contacts the user's hand. The liner
optionally may comprise at least one component selected from of
rayon, acetate, nylon, modacrylic, olefin, PLAY polyester, wool,
cotton, silk, acrylic, blends or conductive woven fiber blends,
metallic fibers or fibers treated with copper, silver, carbon
black, carbon fiber, nickel, tin or other conductive material with
a thickness of less than about 2 mm. In one embodiment, the
material has a volume resistivity of less than about
3.0.times.10.sup.5 Ohm-cm, or alternatively, less than about
3.0.times.10.sup.6 Ohm-cm, or alternatively, less than about
1.0.times.10.sup.6 Ohm-cm and/or a surface resistivity of less than
about 3.0.times.10.sup.5 Ohm-cm, or alternatively, less than about
3.0.times.10.sup.6 Ohm-cm, or alternatively, less than about
1.0.times.10.sup.6 Ohm-cm.
[0122] The electrically conductive thermal insulator layer
comprises a conductive foam, fiber, microfiber, microfilament,
plastic, metal, rubber or breathable thermal insulation with a
volume resistivity of less than 1.0.times.10.sup.6 Ohm-cm and/or a
surface resistivity of less than 1.0.times.10.sup.6 Ohm-cm.
[0123] The conductive fiber, microfiber, microfilament or
breathable thermal, electrically conductive, thermal insulation
comprises materials made from different mixtures of polymers, but
primarily polyethylene terephthalate or a mixture of polyethylene
terephthalate and polypropylene. Other materials may include
polyethylene terephthalate, polyethylene isophthalate copolymer and
acrylic in combination with a conductive coating or impregnated,
embedded, compounded or plated conductive material with a surface
resistance of less than 1.0.times.10.sup.6 Ohm-cm. This can be
accomplished by the use of a chemical reaction to bond the
molecules of carbon black, copper, silver, gold, nickel, tin or
other conductive metal substances, with the molecules of the host
fiber, or by plating or compounding any of these conductive
substances to the host fiber.
[0124] The electrically conductive thermal insulator layer
comprises a conductive foam, rubber, fiber, microfiber or
microfilament.
[0125] The outer shell may comprise at least one conductive
channel, the conductive channel extending from an inner surface of
the outer shell to an outer surface of the outer shell. The glove
may further comprise an outer conductive layer adjacent to the
outer surface of the outer shell. The outer conductive layer
comprises a base coating of polyurethane, polyepoxide, paint,
adhesive, sealant, silicone, resins, polymers, plasticizers, vinyl
compounds or plastics materials with an added electro-conductive
carbon, silver, nickel, copper, tin, gold or other conductive metal
or alloy into the coating in high concentrations to achieve a
surface and/or volumetric resistivity of less than
1.0.times.10.sup.6 Ohm-cm which may or may not be specifically used
to mimic the color, grain, texture and feel of the outer surface of
the outer shell.
[0126] The glove may also have a color layer adjacent the outer
conductive layer, the color layer determining a glove color,
texture, grain or appearance.
[0127] In another embodiment, the invention is directed to a
conductive glove comprising: an outer shell, the outer shell
comprising at least one conductive channel, the conductive channel
extending from an inner surface of the outer shell to an outer
surface of the outer shell, the conductive channel having a
resistivity of less than 1.0.times.10.sup.6 Ohm-cm. The glove may
also have one or more outer conductive layers adjacent to the outer
surface of the outer shell.
[0128] In another embodiment is provided a conducting glove
comprising a nonconductive dielectric outer shell, the
non-conductive outer shell being less than 0.5 mm thick and
electrically conductive thermal insulator layer, with a volume
resistivity of less than 1.0.times.10.sup.6 Ohm-cm, adjacent to the
liner; and an inner liner adjacent to the electrically conductive
insulating layer, the inner liner being less than 2.0 mm thick or
with a volume resistivity of less than 1.0.times.10.sup.6 Ohm-cm
where the capacitive touch screen is capacitively coupled to the
conductive thermal insulator layer, which in turn is electrically
conductive to the conductive inner liner, which in turn is
electrically conductive to the user's skin. The conducting and
insulating layers are located only at specific locations on the
glove, such as the finger and thumb tips.
[0129] In another embodiment, is provided a conducting glove
comprising a nonconductive dielectric outer shell, the
non-conductive outer shell being less than 0.5 mm thick an
electrically conductive thermal insulator layer, with a volume
resistivity of less than 1.0.times.10.sup.6 Ohm-cm, adjacent to the
liner; and a non-conductive dielectric inner liner adjacent to the
electrically conductive insulating layer, the inner layer being
less than 0.5 mm thick where the capacitive touch screen is
capacitively coupled to the conductive thermal insulator layer,
which in turn is capacitively coupled to the user's skin. The
conducting and insulating layers are located only at specific
locations on the glove, such as the finger and thumb tips.
[0130] In still another embodiment is provided a conducting glove
comprising an electrically conductive outer shell, the electrically
conductive outer shell with a volume resistivity of less than
1.0.times.10.sup.6 Ohm-cm an electrically conductive thermal
insulator layer, with a volume resistivity of less than
1.0.times.10.sup.6 Ohm-cm, adjacent to the liner; and a
non-conductive dielectric inner liner adjacent to the electrically
conductive insulating layer, the inner liner being less than 0.5 mm
where the capacitive touch screen is electrically conductive to the
outer shell, which in turn is electrically conductive to the
thermal insulator layer, which is capacitively coupled to the
user's skin. The conducting and insulating layers are located only
at specific locations on the glove, such as the finger and thumb
tips. The conductive fiber, microfiber, microfilament or breathable
thermal, electrically conductive, thermal insulation comprise
materials made from different mixtures of polymers, but primarily
polyethylene terephthalate or a mixture of Polyethylene
terephthalate and polypropylene. Other materials may include
polyethylene terephthalate, polyethylene isophthalate copolymer and
acrylic in combination with a conductive coating or impregnated,
embedded, compounded or plated conductive material with a surface
resistance of less than 1.0.times.10.sup.6 Ohm-cm. This can be
accomplished by the use of a chemical reaction to bond the
molecules of carbon black, copper, silver, gold, nickel, tin or
other conductive metal substances, with the molecules of the host
fiber, or by plating or compounding any of these conductive
substances to the host fiber.
[0131] The electrically conductive insulator layer may comprise a
conductive foam, rubber, fiber, microfiber or microfilament.
[0132] The outer shell may comprise at least one conductive
channel, the conductive channel extending from an inner surface of
the outer shell to an outer surface of the outer shell. The glove
may further comprise an outer conductive layer adjacent to the
outer surface of the outer shell.
[0133] The outer conductive layer comprises a base coating of
polyurethane, polyepoxide, paint, adhesive, sealant, silicone,
resins, polymers, plasticizers, vinyl compounds or plastics
materials with an added electro-conductive carbon, silver, nickel,
copper, tin, gold or other conductive metal or alloy into the
coating in high concentrations to achieve a surface and/or
volumetric resistance of less than 1.0.times.10.sup.6 Ohm-cm which
may or may not be specifically used to mimic the color, grain,
texture and feel of the outer surface of the out shell.
[0134] The glove may further comprise a color layer adjacent the
outer conductive layer, the color layer determining a glove color,
texture, grain or appearance.
[0135] In still yet another embodiment, the invention is directed
to a conductive glove comprising: an outer shell, the outer shell
comprising at least one conductive channel, the conductive channel
extending from an inner surface of the outer shell to an outer
surface of the outer shell, the conductive channel having a
resistance of less than 1.0.times.10.sup.6 ohm-cm. The glove may
further comprise one or more outer conductive layers adjacent to
the outer surface of the outer shell.
[0136] Also encompassed by the invention is a glove with a
non-conductive layer, but that allows capacitive coupling between
the screen and a conductive insulation material, or between the
conductive insulation material and the finger.
[0137] In yet another embodiment, the invention is directed to a
conductive or capacitively coupled glove that is only locally
conductive or capacitively coupled, for example in the finger tip
but not elsewhere. A glove that is a single conductive layer, for
example, is just an outer shell.
[0138] In the following embodiment and method an electrically
conductive glove suitable for interaction with a capacitive touch
screen is described. An electrically conductive glove of the
invention is fabricated in such a manner that the glove material,
which may be non-conductive, or dielectric, initially, is coated,
or treated, with a thin film of a conductive material. The material
of the glove, for example leather, faux leather, suede, polymer,
wool, cotton, fur, nylon, fleece, or any other suitable material,
is coated in such a way that an electrically conductive surface
layer is created on the outside of the glove. This electrically
conductive coating may or may not penetrate into the material of
the glove, but must a form an electrically conductive surface or
surface layer when coated. In this manner the electrically
conductive coating creates an electrical capacitance relative to a
distant ground, or to the capacitive touch device, sufficient to be
detected by a capacitive touch device with or without any grounding
to a user or other ground source. To affect such an electrical
capacitance, the surface area, geometry of the coating, electrical
conductivity, and/or the volume of conductive material are
sufficient to create an electrical capacitance relative to a
distant ground, or to the capacitive touch device, sufficient to be
detected by the capacitive sensors in the capacitive touch device.
The conductive coating may be electrically conductively connected
to the user, it may be electrically capacitively coupled to the
user, or it may be electrically isolated.
[0139] A method for manufacturing of the electrically conductive
glove described above is described here. A glove material is coated
with an electrically conductive coating in such a manner as to coat
the surface, penetrate the glove material, fill pores in a porous
material, fill pores in a fibrous material, coat the fibers of a
fibrous material, or otherwise render the material electrically
conductive on or near its surface. The electrically conductive
coating material may be generally manufactured by using a carrier,
for example a plasticizer, a bulk polymer like acrylic, a weather
proofing, a leather conditioner, an enamel, or any other suitable
carrier, and filling said carrier with an electrically conductive
medium, such as powdered carbon in the form of graphite or carbon
black, powdered metal like silver, powdered indium-tin-oxide (ITO),
electrically conductive polymers, or other powdered electrically
conductive material or materials. The electrically conductive
material may also be manufactured as a solution of one or more
conductive materials, in one or more carriers and/or solvents. Said
electrically conductive coating material is then applied to said
glove material in such a fashion as to coat the surface, bond to
the surface, and/or penetrate the surface in such a fashion as to
create an electrically conductive surface, or near surface, layer
on said glove material. Such electrical volume conductivities of
said electrically conductive glove materials should preferably be
less than 1.0.times.10.sup.6 Ohm-cm, more preferably less than
1.0.times.10.sup.5 Ohm-cm, and most preferably less than
1.0.times.10.sup.4 Ohm-cm.
[0140] A glove pattern is then cut from said electrically
conductive material and fabricated in any standard or non-standard
glove fabrication process such that the electrically conductive
surface is positioned preferably on the outside of one or more of
the materials of the finished glove, but may be positioned on the
inside of one or more of the materials of the finished glove.
[0141] The carbon black impregnated leather can be made into gloves
or other types of instruments where a capacitive coupling is
needed. Due to the treatment of this particular leather as
disclosed herein, there is no need for capacitive coupling from the
screen through the leather to the human body, as the leather itself
is capable of capacitively coupling to the device. The leather is
suitable for all products, such as gloves, where the need for
capacitive coupling without human contact to the screen is
required. Accordingly, a leather is provided herein which carbon
black, or other electrically conductive agent, is suspended and
trapped within the fiber matrix of the skins to create an internal
capacitive network.
[0142] In one embodiment, the present invention is directed to a
glove comprising a tanned leather or leather-like material having
an internal fiber matrix; an electrically conductive agent bonded
to the tanned leather or leather-like material so that the
electrically conductive material penetrates the internal fiber
matrix of the leather or leather-like material and are trapped and
bonded to the fiber matrix; and the electrically conductive agent
creates a capacitive network throughout the substrate and enables a
capacitive coupling to a multi-touch capacitive touch screen
without the need of an electron bridge to the human body.
[0143] In another embodiment, the present invention is directed to
apparel which comprises a textile as disclosed herein having a
fiber matrix which is capable of capacitively coupling to a
multi-touch capacitive touch screen without the need of an electron
bridge to the human body.
[0144] Yet another embodiment of the present invention is directed
to a garment which comprises tanned leather or leather-like
material as disclosed herein having an internal fiber matrix; an
electrically conductive agent bonded to the leather or suffused to
the fibers so that the electrically conductive agent penetrates the
internal fiber matrix and are trapped within and bonded to the
internal fiber matrix; and the trapped particles in the leather
allow an electrostatic discharge of 1.times.10.sup.5 or less.
[0145] Yet another embodiment of the present invention is directed
to footwear which comprises the tanned leather or leather-like
material as disclosed herein having an internal fiber matrix; an
electrically conductive agent bonded to the leather or suffused to
the fibers so that the electrically conductive agent penetrates the
internal fiber matrix and is trapped within and/or bonded to the
internal fiber matrix; and the electrically conductive agent in the
leather or leather-like material provide for an electrostatic
discharge of 1.times.10.sup.5 or less.
EXAMPLES
[0146] The following formulations can be used in the compositions
and methods disclosed herein.
Tanning Example 1
Tanning and Leather Preparation
[0147] Leather tanning is an ancient art, having its beginnings in
South Asia somewhere between 7000-3300 BC. Leather tanning has been
practiced on a wide variety of materials. The process described
herein can be applied to many raw materials, for example including
but not limited to sheep, goat, cow, deer, horse, reptile, bird,
pig and kangaroo skin. The raw material depends upon the
application for the final leather product required.
[0148] All animal skins are made of a fiber matrix that consists of
water, protein, fatty material and mineral salts. These include
elastin, collagen, keratin, albumens, globulins, mucins and
mucoids. The protein may consist of many types, but the important
ones are collagen which, on tanning, gives leather.
[0149] In the first embodiment of the method of the present
invention, the raw material is brought to a fully chrome-tanned
state, which imparts permanency to fiber structure. The chrome
tanning process is described in Leather Technicians Handbook by J.
H. Sharphouse, B.S.c. Leather Producers Association, Kings Park
Road, Moulton Park, Northampton, NN3 1JD U.K. includes a series of
steps as is discussed below.
[0150] 1. First the skins are soaked in drums running at four
revolutions per minute with 300% water at 27.degree. Celsius and
adjusted to a pH of 9.0 with 0.1% non-ionic surfactant. The skins
are drummed intermittently for a period of 6 to 12 hours.
[0151] 2. The skins are then drained.
[0152] 3. The flesh sides of the skins are painted with 15% sodium
hydrogen sulfide (33% strength), 50% hydrated lime and 35% water.
The skins are allowed to pile overnight and then the wool is
removed.
[0153] 4. Next, 600% water and 12% lime are placed in a vat with
agitating paddles run five minutes every four hours for 24 hours.
Then 12% sodium sulfide is added to the vat and the agitating is
continued for an additional 12 hours.
[0154] 5. Next, the flesh is removed from the back side of the skin
with a rotary fleshing machine.
[0155] 6. Next, the skin is washed in soft, running water in a
paddle vat for 30 minutes.
[0156] 7. The skins are de-limed in paddle vats containing 500%
water at 37.degree. Celsius with 1.5% ammonium chloride where the
paddles are run for 60 minutes or until the skins are free of
lime.
[0157] 8. The bating process includes the addition of 1% bacterial
bate with the paddles run for two to three hours.
[0158] 9. Next the skins are pickled in a drum with the pickling
liquor being formed of 200% water at 20.degree. Celsius, 20% salt
and 2% sulfuric acid. The drum is run for 60 minutes, with the
final pickle liquor strength being a 0.5% solution of sulfuric
acid. The drum is then drained and the skins are stored for aging
for several days.
[0159] 10. The Chrome tanning solution is put in the drum. The
tanning solution includes 100% water, 5% salt, 1% chromic oxide (as
10% of chrome liquor of 11% chromic oxide and 33% basicity,
SO.sub.2 reduced) and then 1% chromic oxide (as 10% of the chrome
liquor). The skins are then drummed for from two to six hours in
this mixture until penetrated.
[0160] 11. The skins are then basified. To complete the tannage
between about 3% to about 15%. 0.5-1% sodium bicarbonate should be
added carefully over four hours and then a shrinkage temperature
test should be taken. At the completion of tannage, the pH should
be approximately 4.4 and the shrinkage temperature 98.degree.
Celsius.
[0161] 12. The skins are then piled and drained for 24 hours.
[0162] 13. Then the skins are neutralized thoroughly in the drum
with 150% water and 1.5% ammonium bicarbonate.
[0163] 14. Finally, the skins are washed well, at which point the
leather is fully chrome tanned and ready for the re-tanning by the
impregnation process of the present invention.
[0164] The chrome tanning process described above is well known in
the art. It is provided as a guideline of the primary tanning
process performed on the raw skins prior to the re-tanning process
for impregnation of capacitive material of the present
invention.
[0165] Other chrome tanning processes or even other basic mineral
or vegetable tanning processes can be utilized as the preliminary
tanning method. Chromium sulfate, zirconium, aluminum and vegetable
tannages may also be utilized with the present invention.
Formulation Example 1
Leather
[0166] The leather (Full Grain Hair Sheep Skin) is sprayed with two
layers of the base coat, first at a thickness of from 6.5 to 7.0
G/FT.sup.2 (wet), then at a thickness of 6.0 G/FT.sup.2 (wet), and
then is plated (Sand, 90.degree. C., 50 Kg). A top coat is sprayed
to a thickness of from 1.5 to 2.0 G/FT.sup.2 (wet) and the leather
is subjected to a roto press at 250.degree. C. (low pressure).
Finally, the leather can be milled to achieve the desired visual
and textile effect.
Base Coat
TABLE-US-00008 [0167] Material Used Parts Water 35 Glycol Ether EP
20 Unithane IC-1600 25 Unithane IC-1500 15 Pigment 2.5 Black Carbon
Powder 2.5 Note: The base coat is not filtered before use.
Top Coat
TABLE-US-00009 [0168] Material Used Parts Water 46.4 Unithane
IC-1400 25 Unithane IC-1800 25 Additive IC-04 0.8 Additive IC-05
0.8 Hardener CN 2
Formulation Example 2
British Tan Leather
[0169] The leather (Full Grain Goat Skin) is sprayed with one layer
of the base coat (wet), two layers of the mid coat, and one layer
of the top coat (medium coat). The leather is then tumbled.
Base Coat
TABLE-US-00010 [0170] Material Used Parts Water 30 Glycol Ether EP
15 Unithane IC-1600 30 Unithane IC-1500 10 Pigment 13 Black Carbon
Powder 2
Mid Coat
TABLE-US-00011 [0171] Material Used Parts Water 25 Glycol Ether EP
10 Unithane IC-1600 45 Unithane IC-1500 5 Pigment 15 Black Carbon
Powder 0.5
Top Coat
TABLE-US-00012 [0172] Material Used Parts Water 46.4 Unithane
IC-1400 25 Unithane IC-1800 25 Additive IC-04 0.8 Additive IC-05
0.8 Hardener CN 2
Formulation Example 3
Finished Felt
[0173] The felt is first dipped in base coat and allowed to dry in
an oven at 85.degree. C. The top coat is then sprayed on the
treated felt.
Base Coat
TABLE-US-00013 [0174] Material Used Parts Water 35 Glycol Ether EP
20 Unithane IC-501 25 Unithane IC-1500 15 Pigment 2.5 Black Carbon
Powder 2.5
Top Coat
TABLE-US-00014 [0175] Material Used Parts Water 46.4 Unithane
IC-1400 25 Unithane IC-1800 25 Additive IC-04 0.8 Additive IC-05
0.8 Hardener CN 2
Method Example 1
Impregnating the Leather
[0176] 1. The leather is washed at 110.degree. Fahrenheit for
approximately 1 hour with 200% water of Dry Weight of leather and
1% Formic acid, 1% detergent, 1% wetting agent and 1% Chelating
agent added to the bath.
[0177] 2. The leather is then rinsed at 110.degree. for 10
minutes.
[0178] 3. The leather is then re-floated at 90.degree. F. 100% of
dry weight for 30 minutes. 1% Formic acid, 10% gluteraldehyde, 25%
carbon black is added to the bath.
[0179] 4. A fat liquor at 6% of dry weight is then added to the
bath which consists of a paraffin wax and this is run for three
hours.
[0180] 5. After 3 hours, 20% of the self pacifying chrome is added
to the bath and this is run for 3 hours.
[0181] 6. At the end of the runtime, the leather is then washed and
90.degree. F. for 10 minutes and then cooled at 70.degree. F. for
10 minutes.
[0182] 7. At this point the carbon black has fully penetrated the
fiber matrix of the skins and has bonded with the fibers creating
an internal capacitive network throughout the leather fibers. Other
cent and such as from aldehyde phenols and naphthalene ESD may be
utilized as that of the gluteraldehyde solution and a preferred
embodiment that gluteraldehyde solution utilized in the process may
beat be between one and 7%, and even more preferred range between
two and 5% and even more preferred a 3%. The water component can be
preferably between 25%400%, between about 20 in 80.degree. Celsius;
more preferably between 50% in 200% water between 40 and 60.degree.
C. and even more preferably 100% water between 50.degree. C. carbon
black powder can be mixed in different concentrations down to as
little as 10% depending upon the degree of capacitive nature
required and a physical appearance in color required. Preferably
the carbon black is between one and 25% even more preferably
between 10 and 25% and even more preferably at about 20%. The
amount of carbon black powder utilized varies depending upon the
physical characteristics of the skins being re-tanned and the
primary tanning process utilized. It is important to note that the
proper amount of carbon black be used in the processing of the
re-tanning. If not enough carbon black is used in the process, the
functionality of the leather will not occur. Where a suitable
amount of the carbon black as utilized the full benefits of the
capacitive network throughout the leather skins are achieved. Thus
even though the leather exhibits the surface characteristics of
traditional black leather, the leather will allow a capacitive
coupling a multi touch capacitive touch screen. The times indicated
for the drumming of the carbon black and Glutaraldehyde an
additional drumming of the calcium formate are preferred values and
greater or lesser times may be utilized the following ranges for
the drumming of the leather.
* * * * *