U.S. patent application number 16/469518 was filed with the patent office on 2019-11-21 for exothermic expandable compositions.
This patent application is currently assigned to FOREVER YOUNG INTERNATIONAL, INC.. The applicant listed for this patent is FOREVER YOUNG INTERNATIONAL, INC.. Invention is credited to Daniel L. YOUNG.
Application Number | 20190352552 16/469518 |
Document ID | / |
Family ID | 62559800 |
Filed Date | 2019-11-21 |
United States Patent
Application |
20190352552 |
Kind Code |
A1 |
YOUNG; Daniel L. |
November 21, 2019 |
EXOTHERMIC EXPANDABLE COMPOSITIONS
Abstract
An expandable, exothermic gel-forming composition that is
predominately useful in the consumer products and medical
industries. More particularly, it relates to the use of expandable
particulate exothermic gel-forming compositions with efficient and
long-lasting heat production for heating surfaces and objects
without the need for electricity or combustible fuel.
Inventors: |
YOUNG; Daniel L.;
(Henderson, NV) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FOREVER YOUNG INTERNATIONAL, INC. |
Las Vegas |
NV |
US |
|
|
Assignee: |
FOREVER YOUNG INTERNATIONAL,
INC.
Las Vegas
NV
|
Family ID: |
62559800 |
Appl. No.: |
16/469518 |
Filed: |
December 13, 2017 |
PCT Filed: |
December 13, 2017 |
PCT NO: |
PCT/US2017/066208 |
371 Date: |
June 13, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62433766 |
Dec 13, 2016 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C06B 33/02 20130101;
A61F 7/03 20130101; A47J 36/28 20130101; A61F 2007/0219 20130101;
F24V 30/00 20180501; C06B 23/001 20130101; C09K 5/18 20130101; C09K
5/16 20130101; A61F 2007/038 20130101 |
International
Class: |
C09K 5/18 20060101
C09K005/18; A61F 7/03 20060101 A61F007/03; C06B 33/02 20060101
C06B033/02; C06B 23/00 20060101 C06B023/00; A47J 36/28 20060101
A47J036/28; F24V 30/00 20060101 F24V030/00 |
Claims
1. An expandable, exothermic gel-forming composition comprising:
first and second metallic galvanic alloy particles; a metallic
secondary shell comprised of at least one transitional metal; and a
super absorbent polymer; wherein the first and second metallic
galvanic alloy particles, the metallic secondary shell, and the
super absorbent polymer are blended with each other; wherein the
gel-forming composition expands as the gel-forming composition is
hydrated and generates an exothermic reaction that produces heat
for a predetermined duration of time when exposed to water and an
electrolyte.
2. (canceled)
3. The composition according to claim 1, wherein a powder mixture
is formed from first and second metallic galvanic particles that
are blended with the super absorbent polymer.
4. The composition according to claim 1, wherein the galvanic
metallic alloy particles are blended by a blending apparatus with a
super absorbent polymer to form a homogenous powder mixture.
5. (canceled)
6. The composition according to claim 1, wherein the transitional
metal of the secondary shell consists of Scandium, Titanium,
Vanadium, Chromium, Manganese, Iron, Cobalt, Nickel, Copper, Zinc,
Yttrium, Zirconium, Niobium, Molybdenum, Technetium, Ruthenium,
Rhodium, Palladium, Silver, Cadmium, Hafnium, Tantalum, Tungsten,
Rhenium, Osmium, Iridium, Platinum, Gold, Mercury, Rutherfordium,
Dubnium, Seaborgium, Bohrium, Hassium, Meitnerium, or
Ununnilium.
7. The composition according to claim 1, wherein the transitional
metal of the secondary shell is Manganese Dioxide.
8. The composition according to claim 1, further comprising:
activated carbon blended with the galvanic alloy particles,
secondary shell, and super absorbent polymer, wherein the activated
carbon is blended or alloyed with magnetite and the activated
carbon comprises between 2 and 25% of a total weight of the
composition, and wherein the activated carbon absorbs an odor
produced by the exothermic reaction during gel-formation.
9-11. (canceled)
12. The composition according to claim 1, further comprising: an
electrolyte comprising sodium chloride or calcium chloride, wherein
the super absorbent polymer comprises an absorption capacity of at
least 200 g/g, and wherein the super absorbent polymer is operable
to absorb water without dissolving by solvation of water molecules
via hydrogen bonds.
13. (canceled)
14. The composition according to claim 1, wherein the first and
second galvanic alloy particles comprise magnesium and iron.
15. (canceled)
16. The composition according to claim 14, wherein the super
absorbent polymer is sodium polyacrylamide.
17. The composition according to claim 1, wherein the composition
further comprises potassium permanganate or potassium ferrate.
18-19. (canceled)
20. The composition according to claim 1, wherein the galvanic
alloy particles are formed from a mixture of between 2-20% by
weight iron and 80-98% by weight magnesium.
21. The composition according to claim 1, formed by mixing a weight
ratio of 20:1 to 1:20 galvanic alloy particles to super absorbent
polymer.
22-23. (canceled)
24. The composition according to claim 1, wherein the galvanic
alloy particles are microencapsulated by a polymer.
25. The composition according to claim 24, wherein the polymer is
hydroxypropyl methylcellulose.
26. The composition according to claim 1, wherein the galvanic
alloy particles are encapsulated by a gel formed by the super
absorbent polymer, and wherein the predetermined duration of time
is at least an hour.
27. The composition according to claim 1, wherein the galvanic
alloy particles do not include iron.
28. An expandable, exothermic expandable composition comprising:
first and second galvanic alloy particles; a super absorbent
polymer; and potassium permanganate or potassium ferrate; wherein
the first and second metallic galvanic alloy particles, the
potassium permanganate or potassium ferrate, and the super
absorbent polymer are blended with each other; wherein the
composition expands as the composition is hydrated and generates an
exothermic reaction that produces heat for a predetermined duration
of time when exposed only to water and an electrolyte.
29-30. (canceled)
31. The composition according to claim 28, wherein water and
Hydrogen Peroxide (H.sub.2O.sub.2) are byproducts of the exothermic
reaction.
32. (canceled)
33. The composition according to claim 28, wherein the composition
is disposed in a sealed container comprising a liquid permeable
layer or a steam valve.
34-36. (canceled)
37. The composition according to claim 28, wherein the first and
second galvanic alloy particles comprise MgFe and MnO.sub.2.
38. An expandable, exothermic composition comprising: manganese
dioxide blended with a buffering agent comprising a super absorbent
polymer or a blended mixture of compressed sponge and/or clay
particles; and wherein the gel-forming composition expands as the
gel-forming composition is hydrated and produces heat for a
predetermined duration of time when exposed only to an aqueous
solution comprising hydrogen peroxide.
39-40. (canceled)
41. The composition according to claim 38, wherein the composition
expands to form an exothermic gel or stiff foam.
42. (canceled)
43. The composition according to claim 40, wherein the composition
fluffs up as the composition is hydrated.
44-46. (canceled)
47. The composition according to claim 38, wherein the buffering
agent is a super absorbent polymer, and wherein the manganese oxide
and the super absorbent polymer are blended with each other to form
a homogenous mixture.
48-51. (canceled)
52. The composition according to claim 1, wherein over at or about
40%, over at or about 45%, over at or about 50%, over at or about
55%, over at or about 60%, over at or about 65%, over at or about
70%, over at or about 75%, over at or about 80%, over at or about
85%, over at or about 90%, or over at or about 95% of hydrogen
gases produced by the exothermic reaction are suppressed and not
released from the composition during the exothermic reaction.
53-60. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional
Application Ser. No. 62/433,766, filed on Dec. 13, 2016, the
contents of which are incorporated into this application by
reference in their entirety as if set forth verbatim.
FIELD
[0002] This disclosure relates generally to exothermic compositions
that are predominately useful in the consumer products and medical
industries.
BACKGROUND
[0003] The ability to produce heat without the use of electricity
or burning fuels is desirable in many applications. In the cosmetic
industry, heat is desired for the application of various cosmetics
to the skin and scalp. In the medical profession, application of
heat is important in physical therapy, orthopedics, wound healing,
arthritis treatment, etc. In consumer products, the ability to keep
food and other substances hot, as well as to heat them initially,
is desired when other means of heating are not convenient or
unavailable.
[0004] The utility of exothermic chemical reactions in such
applications has been described. For example, the military has used
a "flameless heating device" for heating rations in the field since
at least 1973. These devices are in the form of a "hot sheet"
consisting of a magnesium anode, a carbon electrode and an
electrolyte salt. More recently, the military developed a
dismounted ration heating device (DRHD) utilizing chemical heating
pads composed of magnesium-iron alloy particles trapped in a
semi-solid polyethylene matrix (See, e.g., U.S. Pat. No.
4,522,190).
[0005] Other examples of metal alloy particles to produce heat in
the cosmetic industry have been described for use in conjunction
with paper-based "fluff" as the absorptive material. However, such
systems have relatively low energy potential and thus exhibit a
short duration exothermic reaction, as well as non-uniform
heating.
[0006] Accordingly, there is a need for compositions that can be
used to generate heat in a convenient format that is safe, uniform,
controllable and long-lasting. Therefore, a need exists to resolve
these and other problems in the art.
SUMMARY
[0007] The following simplified summary is provided in order to
provide a basic understanding of some aspects of the claimed
subject matter. This summary is not an extensive overview, and is
not intended to identify key/critical elements or to delineate the
scope of the claimed subject matter. Its purpose is to present some
concepts in a simplified form as a prelude to the more detailed
description that is presented later.
[0008] In one embodiment, an expandable, exothermic particulate
gel-forming composition is provided that includes first and second
metallic galvanic alloy particles (or at least two different
metallic galvanic alloy particles that are optionally alloyed
together). In other embodiments, more than two different metallic
galvanic alloy particles can be provided. A metallic secondary
shell comprised of at least one transitional metal; and a super
absorbent polymer; wherein the first and second metallic galvanic
alloy particles (or each of the two or more different metallic
galvanic alloy particles), the metallic secondary shell, and the
super absorbent polymer are blended with each other; wherein the
gel-forming composition expands as the gel-forming composition is
hydrated and generates an exothermic reaction that produces heat
for a predetermined duration of time when exposed to water and an
electrolyte. The first and second metallic galvanic alloy
particles, the metallic secondary shell, and the super absorbent
polymer in some embodiments are blended with each other are brought
into electrical contact. In some embodiments, a powder mixture is
formed from first and second metallic galvanic particles that are
blended with the super absorbent polymer. The predetermined
duration of time can range from several minutes (e.g., 5 minutes)
to several hours (e.g., 8 hours) but can be any duration of time
desired or needed. The term "pre-determined" used in connection
with a duration of time in this disclosure can be something that is
known or expected based on the respective composition but not
determined at each instance or necessarily known to a user unless
specifically defined as such.
[0009] The claimed compositions provide gas suppression, for
example hydrogen gas suppression, or suppression of gases typically
generated by the underlying exothermic reaction such that these
gasses do not escape the formed compositions (referring to the
reacted, reacting, formed, gel/foam, expanding or expanded,
exothermic, etc. composition) or their escape is suppressed to a
significant degree discussed herein. In certain embodiments, a
majority (or percentage described herein) of the gases produced by
the exothermic reaction are suppressed and not released from the
composition during the exothermic reaction.
[0010] In some embodiments, activated carbon is used with the
composition as an odor absorber. The activated carbon can be
present in an amount of about 2 to 25% of the composition.
Activated carbon can include a combination of graphite materials,
other carbon powders in various particle sizes.
[0011] In one embodiment, an expandable exothermic composition can
include two or more different metallic particles, each having a
different oxidation potential. A metallic secondary shell can be
included having at least one transitional metal. A super absorbent
polymer can also be included. The first and second metallic
galvanic alloy particles, the metallic secondary shell, and the
super absorbent polymer can be blended with each other (e.g., to a
uniform powder mixture) and the gel-forming composition can expand
as the gel-forming composition is hydrated to generate an
exothermic reaction that produces heat for a predetermined duration
of time when exposed to water and an electrolyte. In certain
embodiments, a majority (or percentage described herein) of the
gases produced by the exothermic reaction are suppressed and not
released from the composition during the exothermic reaction.
[0012] In often included embodiments, an expandable, exothermic
composition is provided comprising: first and second galvanic alloy
particles (or at least two different metallic galvanic alloy
particles that are optionally alloyed together); a super absorbent
polymer; and potassium permanganate or potassium ferrate; wherein
the first and second metallic galvanic alloy particles (or each of
the two or more different metallic galvanic alloy particles), the
potassium permanganate or potassium ferrate, and the super
absorbent polymer are blended with each other; wherein the
composition expands as the composition is hydrated to generate an
exothermic reaction and produces heat for a predetermined duration
of time when exposed only to water and an electrolyte. In certain
embodiments, the first and second galvanic alloy particles comprise
MgFe and MnO.sub.2. Also frequently, between about 37% to about
93%, or over 93%, of gases produced by the exothermic reaction are
suppressed and not released from the composition during the
exothermic reaction.
[0013] In another embodiment, an expandable, exothermic composition
is provided comprising: manganese oxide blended with a super
absorbent polymer; and wherein the composition expands as the
gel-forming composition is hydrated to generate an exothermic
reaction and produces heat for a predetermined duration of time
when exposed only to an aqueous solution. In some embodiments, the
manganese oxide is manganese dioxide. In certain related
embodiments, a majority (or percentage described herein) of the
gases produced by the exothermic reaction are suppressed and not
released from the composition during the exothermic reaction.
[0014] In some embodiments, the composition expands to form a stiff
foam. In some embodiments, the composition fluffs up as the
composition is hydrated. In some embodiments, the aqueous solution
is hydrogen peroxide and the buffering agent is a blended mixture
of compressed sponge and/or clay particles. In this regard
embodiments, the composition of this embodiment can expand to form
a stiff foam. In certain related embodiments, a majority (or
percentage described herein) of the gases produced by the
exothermic reaction are suppressed and not released from the
composition during the exothermic reaction.
[0015] Kits are also provided, for example a kit comprising: a
container; an exothermic particulate gel-forming composition
according to any of the preceding claims;-an aqueous activator
solution, wherein the super absorbent polymer is operable to absorb
the aqueous activator solution so that the gel-forming composition
expands as the gel-forming composition is hydrated; and
instructions specifying that the composition is activated in the
absence of air upon contact with the aqueous activator solution to
produce heat for a predetermined duration of time.
[0016] In another embodiment, an expandable, exothermic particulate
gel-forming composition is provided comprising: first and second
metallic galvanic alloy particles comprising magnesium and iron; a
metallic secondary shell comprised of at least one transitional
metal comprising manganese dioxide; and a super absorbent polymer
comprising sodium polyacrylamide; wherein the first and second
metallic galvanic alloy particles, the metallic secondary shell,
and the super absorbent polymer are blended with each other;
wherein the gel-forming composition expands as the gel-forming
composition is hydrated and generates an exothermic reaction that
produces heat for a predetermined duration of time when exposed to
water and an electrolyte. In certain related embodiments, a
majority (or percentage described herein) of the gases produced by
the exothermic reaction are suppressed and not released from the
composition during the exothermic reaction.
[0017] In another embodiment, an expandable, exothermic composition
is provided having first and second metallic galvanic alloy
particles comprising magnesium and manganese oxide (i.e. whereby
the galvanic alloy particles do not include iron). A super
absorbent polymer can be included as well as a carbon particles.
The first and second metallic galvanic alloy particles, the super
absorbent polymer, and the carbon can be blended with each other.
The composition expands as the composition is hydrated with water
and no electrolyte such as salt is necessary for inclusion in the
water. Hydrating the composition can generate an exothermic
reaction that produces heat for a predetermined duration of time.
In certain related embodiments, a majority (or percentage described
herein) of the gases produced by the exothermic reaction are
suppressed and not released from the composition during the
exothermic reaction.
[0018] In another embodiment, an expandable, exothermic
(particulate) gel-forming composition is provided comprising: first
and second galvanic alloy particles comprising magnesium and iron;
a super absorbent polymer comprising sodium polyacrylamide; and
potassium permanganate or potassium ferrate; wherein the first and
second metallic galvanic alloy particles, the potassium
permanganate or potassium ferrate, and the super absorbent polymer
are blended with each other; wherein the gel-forming composition
expands as the gel-forming composition is hydrated and produces
heat for a predetermined duration of time when exposed only to
water and an electrolyte. In certain related embodiments, a
majority (or percentage described herein) of the gases produced by
the exothermic reaction are suppressed and not released from the
composition during the exothermic reaction.
[0019] In another embodiment, an expandable, exothermic composition
that is fluffable and/or swellable is provided comprising:
manganese oxide blended with a super absorbent polymer comprising
sodium polyacrylamide. This embodiment can use a super absorbent
polymers disclosed herein that are not sodium polyacrylamide. The
composition expands as the composition is hydrated and produces
heat for a predetermined duration of time when exposed only to an
aqueous solution. In certain related embodiments, a majority (or
percentage described herein) of the gases produced by the
exothermic reaction are suppressed and not released from the
composition during the exothermic reaction.
[0020] In another embodiment a kit is provided comprising: a
container; an exothermic particulate gel-forming composition
according to any of the preceding claims; an aqueous activator
solution comprising water or a saline solution, wherein the super
absorbent polymer is operable to absorb the aqueous activator
solution so that the gel-forming composition expands as the
gel-forming composition is hydrated; and instructions specifying
that the composition is activated in the absence of air upon
contact with the aqueous activator solution to produce heat for a
predetermined duration of time.
[0021] In frequent embodiments contemplated herein, the composition
is adapted to provide for minimal or approximately zero gases to be
produced or released from the composition (referring to the
reacted, reacting, formed, gel/foam, expanding or expanded,
exothermic, etc. composition) during or otherwise as a result of
the exothermic reaction. Often, between about 37% to about 93% of
gases produced by the exothermic reaction are suppressed and not
released from the composition during or otherwise as a result of
the exothermic reaction. Also often, between about 93% to about
100% of gases produced by the exothermic reaction are suppressed
and not released from the composition during or otherwise as a
result of the exothermic reaction. In frequently included
embodiments, over at or about 40%, over at or about 45%, over at or
about 50%, over at or about 55%, over at or about 60%, over at or
about 65%, over at or about 70%, over at or about 75%, over at or
about 80%, over at or about 85%, over at or about 90%, or over at
or about 93%, or over at or about 95% of gases produced by the
exothermic reaction are suppressed and not released from the
composition (again, referring to the reacted, reacting, formed,
gel/foam, expanding or expanded, exothermic, etc. composition)
during or otherwise as a result of the exothermic reaction.
[0022] Other aspects of the disclosed solution are found throughout
the specification. To the accomplishment of the foregoing and
related ends, the aspects disclosed in the specification are
indicative, however, of but a few of the various ways in which the
principles of the claimed subject matter may be employed and the
claimed subject matter is intended to include all such aspects and
their equivalents. Other advantages and novel features may become
apparent from the following detailed description.
DETAILED DESCRIPTION
[0023] This solution is in the field of expandable, exothermic
gel-forming compositions that are predominately useful in the
consumer products and medical industries. More particularly, the
herein disclosed solution relates to the use of expandable,
particulate exothermic gel-forming compositions with long-lasting
and efficient heat production for heating surfaces and objects in
the absence of air without the need for electricity or combustible
fuel. The exothermic gel-forming compositions of the present
disclosure are generally formulated from several approaches.
[0024] Terms with commonly understood meanings may be defined
herein for clarity and/or for ready reference, and the inclusion of
such definitions herein should not necessarily be construed to
represent a substantial difference over what is generally
understood in the art. All patents, applications, published
applications and other publications referred to herein are
incorporated by reference in their entirety. If a definition set
forth in this section is contrary to or otherwise inconsistent with
a definition set forth in the patents, application, published
applications and other publications that are herein incorporated by
reference, the definition set forth in this section prevails over
the definition that is incorporated herein by reference.
[0025] As used herein, "a" or "an" means "at least one" or "one or
more."
[0026] As used herein, the term "user," "subject," "end-user" or
the like is not limited to a specific entity or person. For
example, the term "user" may refer to a person who uses the systems
and methods described herein, and frequently may be a technician.
However, this term is not limited to end users or technicians and
thus encompasses a variety of persons who can use the disclosed
systems and methods.
[0027] The disclosed solution can now be better understood turning
to the following detailed description. It is to be expressly
understood that the described embodiments are set forth as examples
and not by way of limitations on the embodiments as ultimately
defined in the claims.
[0028] It is understood that "galvanic alloy" can mean a metal that
is made by combining two or more metallic elements, including
combining two or more different metal salts. The combination is
often via a known means for alloying, including for example using
an alloying process using a ball mill or the like.
[0029] It is understood that the term "blended" can mean blending
two or more things together to form a mixture, such as a blended
powder (uniformly or otherwise), homogeneous mixture or homeogenous
powder. A blender that can be used to "blend" two or more things
together can include commercially available mixers and blenders,
such as drum mixers, braun mixers, ribbon blenders, blade blenders,
V-shaped blenders, batch mixers, or the like.
[0030] It is understood that the term, "activator solution," can
mean water, water and an electrolyte, or other aqueous solution
that when contacted with any of the exothermic compositions of this
disclosure initiates, increases or renews an exothermic
reaction.
[0031] As used herein, the term "gel" is intended to refer to
materials traditionally known in the art as gels, in addition to
foams and combinations thereof. Often, when formed, the foam is a
foam having a certain level of structural rigidity or shape
adherence such as a stiff foam. Such stiff foam may be capable of
withstanding deformation against a certain level of outside force
or be a self-supporting foam composition. As such, a gel-forming
composition is intended herein to refer to a gel-forming
composition and unless specifically indicated otherwise, also
refers to a foam-forming composition. Also for example, an
exothermic gel is intended herein to refer to an exothermic gel
composition and unless specifically indicated otherwise, also
refers to an exothermic foam composition. Also for example, a
swelling gel or a gel matrix also, therefore, is intended to refer
herein to a swelling foam or a foam matrix unless specifically
indicated otherwise.
[0032] As used herein, an "exothermic composition" may be referred
to as an "exothermic composition" prior to, during, or after
initiation of an exothermic reaction using the composition.
[0033] The use of self-heating compositions is well known.
Magnesium-Iron alloys activated by salt and water have been used by
the military and recreational markets for decades. All of these
reactions, however, are uncontrollable, violent and short in
duration. These reactions use an oxidation-reduction reaction to
effectively oxidize the metallic elements by splitting the water
molecule into oxygen to produce heat while liberating hydrogen gas.
This evolution of hydrogen gas can be a major limiting factor as to
where these compositions can be used because of the explosive
nature of hydrogen gas under normal atmospheric conditions.
[0034] Prior approaches to self-heating have incorporated galvanic
alloys (e.g. Mg--Fe alloys) in combination with a super absorbent
polymer (SAP). In turn, such approaches have achieved self-swelling
gels formed by a fluffing action upon contact of the SAP with an
aqueous solution (e.g. water or saline solution). This in turn
permits the corresponding exothermic gel to expand to contour
around objects and fill voids. More importantly, the swellable
agents of the SAP electronically interfere with the oxidation
process of the Mg--Fe, and with an understanding of the hydrogen
bonding forces at play within the reaction, a controlled reaction
can be designed with a calculated output of heat over a known time
period. The heat-vs-time buffering effect of the SAP works within
its own structure by utilizing the electron sharing and
hydrogen-bonding forces in a tug-of-war between the oxidation
tendencies of the galvanic alloy in the presence of water and an
electrolyte. More specifically, a salt solution and the electronic
attraction forces of the SAP matrix, namely hydrogen bonding and
valence sharing. But as applicable as a controlled, calculated,
time-release exothermic reaction powered by water can be, it still
has the disadvantage of evolving hydrogen gas as a byproduct of the
reaction.
Galvanic Alloy Particles
[0035] As discussed throughout this disclosure, those embodiments
of the disclosed solution that include galvanic alloy (GA)
particles can consist of a mixture of two or more metallic agents,
each with a different oxidation potential, such that one serves as
the cathode and the other serves as the anode in an electrochemical
reaction, once the two components of the composition are brought
into electrical contact with one another via an activator
solution.
[0036] Exemplary metallic agents can include mixtures of copper,
nickel, palladium, silver, gold, platinum, carbon, cobalt,
aluminum, lithium, iron, iron(II)oxide, iron(III)oxide, magnesium,
manganese, Mg.sub.2Ni, MgNi.sub.2, Mg.sub.2Ca, MgCa.sub.2,
MgCO.sub.3, MnO.sub.2, and combinations thereof. For example,
platinum may be dispersed on carbon and this dispersion used as a
cathode material. See, e.g., U.S. Pat. Nos. 3,469,085; 4,264,362;
4,487,817; and 5,506,069.
[0037] An exemplary anode material is magnesium, which reacts with
water to form magnesium hydroxide (Mg(OH)2) and hydrogen gas to
generate large amounts of heat. Other metallic agents having high
standard oxidation potentials (such as lithium) may also serve as
the anode material, but are less preferred from a cost and safety
standpoint. The cathode material will have a lower standard
oxidation potential than the anode material. The cathode is not
consumed in the electrochemical interaction, but serves as a site
for electrons given up by the corroding anode to neutralize
positively charged ions in the electrolyte. Exemplary cathode
materials include iron, copper and cobalt.
[0038] In certain exemplary embodiments, the galvanic alloy
comprises two different alloys that are alloyed together. Most
often, such an alloy comprises a combination of two different
galvanic alloys described and/or contemplated herein. For example,
in one embodiment, the galvanic alloy comprises MgFe alloyed with
MnO.sub.2.
[0039] Any of the usual methods can be employed in the production
of a galvanic alloy, such as conventional dissolution or mechanical
alloying. The process of mechanical alloying involves, for example,
inducing a solid state reaction between the components of an
initial powder mixture by repeated mechanical deformations caused
by ball-powder-ball collisions using a high energy ball mill. Such
mechanical deformations may include, for example, repeated
flattening, fracturing, and welding of metal constituents e.g.,
active and passive metal particles. The resultant energy produced
from the impact of colliding steel balls with particles trapped
between them creates atomically clean particle surfaces. These
atomically clean particle surfaces allow them to cold-weld
together.
[0040] The particle sizes of the metallic components before milling
may vary from a few microns to a few hundred microns. In one
embodiment, it may be desirable to have an average particle size
less than 200 microns, such as 100-150 microns, to facilitate
efficient alloying.
[0041] Exposure to oxygen or certain other reactive compounds
produces surface layers that reduce or completely eliminate the
cold welding effect. Therefore, an inert atmosphere can be
maintained in the mill to prevent reoxidation of the clean
surfaces, thereby avoiding the formation of oxide coatings on the
particle surfaces which reduce galvanic cell reactions. An "inert
gas" as used herein is an unreactive gas, such as nitrogen, helium,
neon, argon, krypton, xenon, radon and also includes the
nonoxidizing gas, carbon dioxide. The inert gas should be
essentially free of water (less than 10 ppm, such as less than 5 or
less than 1 ppm).
[0042] Generally, when the milling process is allowed to progress
for an extended period of time, the particle structure becomes more
refined and the cathode particles reduce in size. However, after a
certain point in the milling process, any additional milling will
result in a reduction of the corrosion rate due to the cathode
material becoming too finely dispersed throughout the anode
material. When this occurs, the ratio of cathode/anode particle
surface area available for contact with the electrolyte decreases
and hence the corrosion rate decreases. The resulting mechanically
alloyed powders from a milling process are small particles
consisting of matrices of active metal having smaller particles of
passive metals dispersed throughout. Accordingly, milling time
should be optimized for the best outcome in terms of electrical
conductivity. In one embodiment, the galvanic alloy particles
consist of magnesium and nickel, magnesium and iron, magnesium and
copper, and magnesium and cobalt (U.S. Pat. No. 4,264,362). In
magnesium-containing alloys, the magnesium is usually present in
greater abundance, such as greater than 75%, 80%, 90% or 95% by
weight.
Super Absorbent Polymer
[0043] In those embodiments of the disclosed solution that include
a superabsorbent polymer (SAP), it is understood that SAP can be a
"slush powder," "water-insoluble absorbent hydro gel-forming
polymer," "hydrogel-forming" polymer or "hydrocolloid." The use of
SAP is important because, when combined with an aqueous solution, a
gel that expands can be created. This water-based gel can store a
significant amount of the heat generated by the exothermic reaction
due to its high specific heat capacity. Thus, the gel stays hot for
a relatively long period of time (compared to the exothermic
reaction carried out in the absence of gel). The gel also prolongs
the duration of time that the object being heated can be maintained
at a relatively constant elevated temperature. Additionally, as the
gel-forming composition expands, heat can be transferred to more
surface area of external objects than if the gel did not
expand.
[0044] The term "super absorbent polymer" can be any polymer
capable of swelling to 200 gms per gm of dry polymer when exposed
to water. Generally, SAPs are loosely cross-linked,
three-dimensional networks of flexible polymer chains that carry
dissociated, ionic functional groups. The absorption capacity of a
SAP relative to a particular material, such as water, is determined
by osmotic pressure and the polymer's affinity with that material
as well as the polymer's rubber elasticity.
[0045] The difference between the ion concentration inside a SAP
and that of the surrounding water solution determines the intensity
of available osmotic pressure. Therefore, the osmotic pressure
enables a SAP to absorb a large quantity of water. Additionally, a
particular polymer's affinity for its surrounding solution also
affects the absorption capacity of the polymer. Thus, based on a
polymer's absorptive capacity due to the surrounding osmotic
pressure and the polymer's affinity for water, a SAP can absorb
large quantities of water and other aqueous solutions without
dissolving by solvation of water molecules via hydrogen bonds,
increasing the entropy of the network to make the SAPs swell
tremendously.
[0046] The factor that suppresses a SAP's absorbing power, in
contrast, is found in the elasticity of the gel resulting from its
network structure. The rubber-like elasticity of a polymer
increases with the crosslinking density of the polymer, wherein the
absorption capacity of a given SAP reaches its maximum when its
rubber elasticity attains equilibrium with its water absorbing
power.
[0047] Examples of SAPs can include a polyacrylic acid salt-based
polymer, a vinyl alcohol-acrylic acid salt-based polymer, a PVA
based polymer or an isobutylene-maleic anhydride polymer. Other
examples of SAPs include polysaccharides such as carboxymethyl
starch, carboxymethyl cellulose and hydroxypropyl cellulose;
nonionic types such as polyvinyl alcohol and polyvinyl ethers;
cationic types such as polyvinyl pyridine, polyvinyl morpholinione,
and N,N-dimethylaminoethyl or N,N-diethylaminopropyl acrylates and
methacrylates; and carboxy groups which include hydrolyzed
starch-acrylonitrile graft copolymers, partially neutralized
hydrolyzed starch-acrylonitrile graft copolymers, hydrolyzed
acrylonitrile or acrylamide copolymers and polyacrylic acids.
[0048] Methods of making SAPs are well known and can be easily
optimized to achieve a desired swellability. For example, SAPs can
be made from the polymerization of acrylic acid blended with sodium
hydroxide in the presence of an initiator to form a polyacrylic
acid sodium salt (i.e. "sodium polyacrylate.) Other materials also
used to make SAPs are polyacrylamide copolymer, ethylene maleic
anhydride copolymer, cross-linked carboxy-methyl-cellulose,
polyvinyl alcohol copolymers and cross-linked polyethylene
oxide.
[0049] Although there are many types of SAPs commercially
available, most are lightly cross-linked copolymers of acrylate and
acrylic acid, and grafted starch-acrylic acid polymers prepared by
inverse suspension, emulsion polymerization or solution
polymerization. Inverse suspension polymerization is generally used
to prepare polyacrylamide-based SAPs and involves dispersing a
monomer solution in a non-solvent, forming fine monomer droplets to
which a stabilizer is added. Polymerization is then initiated by
radicals from thermal decomposition of an initiator.
[0050] SAPs found to be particularly suitable include, for example,
AQUA KEEP.RTM. Super Absorbent Polymer manufactured by Sumitomo
Seika Chemical Company (Osaka, Japan). For some embodiments, a
fast-acting version of AQUA KEEP.RTM. found to be suitable is AQUA
KEEP.RTM. 10SH-P. Additional polymers can be found commercially as
CABLOC 80HS, available from Stockhausen Inc., Greensboro, N.C.;
LIQUIBLOCK.RTM. 2G-40, available from Emerging Technologies, Inc.,
Greensboro, N.C.; SANWET IM1000F, available from Hoechst Celanese
Corporation, Bridgewater, N.J.; AQUALIC CA, available from Nippon
Shokubai Co., Ltd., Osaka, Japan; and SUMIKA GEL, available from
Sumitomo Kagaku Kabushiki Kaisha, Japan. Additional SAPs are also
commercially available from a number of manufacturers, such as Dow
Chemical (Midland, Mich.) and Chemdal (Arlington Heights, Ill.).
Any of the aforementioned SAPs can be included as a blend of two or
more polymers, so long as the majority of the polymer (more than
50% and preferably more than 70%, weight per weight) has an
absorption capacity equal to or greater than 200 gms per gram.
[0051] Absorption measurements can be conducted under several
methods, including the tea-bag method, centrifuge method and sieve
method. According to the tea-bag method, a sample is placed in a
bag measuring about 5.times.5 cm and the bag is then sealed around
its perimeter. The bag is then placed in a dish with an excess of
either water or 0.9% NaCl solution and the sample is allowed to
absorb the solution and swell freely in the bag for one hour or
until it reaches equilibrium. The bag is then removed to separate
the sample from any excess solution and weighed to calculate the
swelling capacity. The absorption capacity of the polymer sample
can then be calculated in accordance with the following
formula:
A s = m m - m b ( 1 + A b ) - m s m s ##EQU00001##
[0052] Where: A.sub.s=sample absorbency; A.sub.b=tea bag material
absorbency; m.sub.m=weight of tea bag with sample after absorption;
m.sub.b=weight of empty, dry tea bag; and m.sub.s=weight of dry
sample.
[0053] In one embodiment, the SAP (or at least a majority of the
SAP if a blend of two or more is used) has an absorption capacity
of at least 200 g/g, where 1 g of SAP is capable of absorbing up to
200 g of water. The SAP can also be a fast acting polymer with an
absorption rate of no more than 20 seconds, and more preferably no
more than 10 seconds or no more than 5 seconds.
Encapsulation
[0054] All of the disclosed embodiments can be further processed to
include some degree of encapsulation of components to control the
exothermic reaction. For example, one approach is to encapsulate
the GA particles or the gel-forming composition to both extend its
shelf life and control the release of energy once exposed to the
activating solution. "Encapsulation," as used herein, means that at
least portions of the GA or other parts of the gel-forming
composition are substantially enclosed in a suitable encapsulation
material, such that the encapsulation material is adhered to the
surface of the particles. "Suitable encapsulation material," or
"encapsulant," as used herein, means a material that is
sufficiently robust to withstand formulation and manufacturing
conditions of the gel-forming compositions, is compatible with the
formulation and does not adversely impact its performance, with the
caveat that extending heat production is not an adverse effect. In
addition, a suitable encapsulation material adheres to the
composition. Adhesion of the encapsulant may occur through covalent
chemical bonding or through non-covalent interactions (e.g., ionic,
Van der Waals, dipole-dipole, etc.).
[0055] "Microencapsulated," as used herein, means that the average
diameter of the encapsulated component is from about 1 .mu.m to
about 1000 .mu.m. If the encapsulated component is oblong or
asymmetrical, then the average diameter is measured across that
part of the component having the greatest length. In one
embodiment, all or some portion of the foregoing compositions can
be microencapsulated, and the encapsulated product has an average
diameter from about 1 .mu.m to about 1000 .mu.m, alternatively from
about 1 .mu.m to about 120 .mu.m, alternatively from about 1 .mu.m
to about 50 .mu.m, and alternatively from about 1 .mu.m to about 25
.mu.m. In another embodiment, the encapsulated product has an
average diameter from about 100 .mu.m to about 800 .mu.m, or from
about 500 .mu.m to about 700 .mu.m, such as 600 .mu.m.
[0056] Non-limiting examples of suitable encapsulation materials
include polystyrene, methacrylates, polyamides, nylons, polyureas,
polyurethanes, gelatins, polyesters, polycarbonates, modified
polystyrenes, and ethylcellulose degradable polymer matrices. In
one embodiment, the encapsulation material is
poly(lactide-co-glycolide) (PLG), poly(glycidylmethacrylate)(PGMA),
polystyrene, or combinations thereof. In an alternative embodiment,
the encapsulant is hydroxypropyl methylcellulose. Suitable
encapsulation materials may have a molecular weight of from about 5
kDa to about to about 250 kDa, alternatively from about 200 kDa to
about 250 kDa, alternatively from about 50 kDa to about 75 kDa,
alternatively from about 10 kDa to about 50 kDa and alternatively
from about 10 kDa to about 25 kDa.
[0057] It should also be understood that it is possible to
encapsulate any or all of the alloy components (i.e., both the
cathode and anode), either the cathode and/or the anode separately,
with or without a binder. Through routine optimization using
different combinations of coatings of varying components and using
known encapsulation techniques, the ideal encapsulation format can
be determined based on the use to which the composition is being
put. For example, for a body wrap intended to achieve a therapeutic
benefit for a longer period of time, a less dissolvable coating
would be desirable to extend the time period of the heat
production. Alternatively, for the administration of a medicament,
a more dissolvable coating would be desirable to achieve a higher
temperature over a shorter time span.
[0058] The chemical properties of the above-described coatings and
their use in a variety of fields such as nanotechnology, energetic
materials and the medical field is well known and such optimization
could be easily achieved based on this vast body of knowledge.
Binders
[0059] The gel-forming composition can also include at least one
binder, such as a polymer or plastic, in addition to the SAP.
Exemplary binders include natural resins, synthetic resins,
gelatins, rubbers, poly(vinyl alcohol)s, hydroxyethyl celluloses,
cellulose acetates, cellulose acetate butylates,
poly(vinylpyrrolidone)s, casein, starch, poly(acrylic acid)s,
poly(methylmethacrylic acid)s, poly(vinyl chloride)s,
poly(methacrylic acid)s, styrene-maleic anhydride copolymers,
styrene-acrylonitrile copolymers, styrene-butadiene copolymers,
poly(vinyl acetal)s (e.g., poly(vinyl formal) and poly(vinyl
butyral)), poly(ester)s, poly(urethane)s, phenoxy resins,
poly(vinylidene chloride)s, poly(epoxide)s, poly(carbonate)s,
poly(vinyl acetate)s, poly(olefin)s, cellulose esters, and
poly(amide)s. The binders may added to the gel-forming composition
as a solution or emulsion in water or an organic solvent and
blended together using known methods.
Hydrogen Gas Suppression
[0060] As contemplated herein, gas suppression and in particular
hydrogen gas suppression, is viewed relative to a similar or
identical non-suppressed reaction. In a non-suppressed reaction,
gas is freely produced at a known level, previously known level, or
a level that can be calculated based on the reactants. Gas
suppression as contemplated herein refers to a percentage reduction
in gas production and release from the formed exothermic
composition (e.g., gel, foam, etc.) relative to a non-suppressed
reaction. Experimental data provided herein for an exemplary
embodiment demonstrates over 90% gas suppression, though higher
levels of gas suppression are contemplated up to and including 100%
gas suppression. In certain embodiments, a gas suppression of
between at or about 30% to at or about 95% is provided. In certain
embodiments, a gas suppression of at or about 37%, or over about
37%, is provided. In certain embodiments, a gas suppression of
between about 37% to 93%, at or about 93%, or over about 93%, is
provided.
[0061] In one embodiment, a gel-forming exothermic composition that
suppresses hydrogen gas byproduct can be prepared from a homogenous
mixture of SAP, one or more GA particles, and a metal with
secondary shell or electronic orbit bonding properties, also
referred to as metallic secondary shells. This metallic secondary
shell can inhibit or prevent the formation of hydrogen gas due to
reaction with the secondary shell electrons or within the electron
sharing patterns, eliminating the hydrogen byproduct at outermost
surfaces of the GA alloy particles. Effectively, the metallic
secondary shell thwarts the production of hydrogen gases at the
surface level. Typically, most elements can only use electrons from
their outer orbital to bond with other elements. These metals with
"secondary-shell" bonding properties can use the two outermost
shells/electron orbitals, e.g. the s orbitals, d orbitals, p
orbitals and/or f orbitals common to the electronic structure of
these metallic secondary shells, to bond with other elements to
produce unexpected combinations. In the case of this embodiment,
instead of the hydrogen atom being reduced and becoming H.sub.2 or
molecular hydrogen gas, it is inhibited by this secondary
interaction as it bonds with the elemental Magnesium atoms,
Magnesium Hydroxide, Magnesium Oxide and/or water molecules.
[0062] Exemplary metallic secondary shells can include transitional
metals such as Scandium, Titanium, Vanadium, Chromium, Manganese,
Iron, Cobalt, Nickel, Copper, Zinc, Yttrium, Zirconium, Niobium,
Molybdenum, Technetium, Ruthenium, Rhodium, Palladium, Silver,
Cadmium, Hafnium, Tantalum, Tungsten, Rhenium, Osmium, Iridium,
Platinum, Gold, Mercury, Rutherfordium, Dubnium, Seaborgium,
Bohrium, Hassium, Meitnerium, and Ununnilium.
[0063] One embodiment of the metallic secondary shells can include
Manganese Dioxide. Manganese Dioxide is an effective inhibitor for
hydrogen gas, is relatively inexpensive, readily available, safe
and harmless to the environment, people, plant and animal life.
[0064] Any of the herein disclosed metallic secondary shells can be
combined with the GA particles by milling them together with a ball
mill, and then further mixing the Super Absorbent Polymer (SAP)
materials together with the composition. In certain embodiments, a
homogenous mixture can be generated using any of a variety of
commercially available mixers and blenders, such as drum mixers,
braun mixers, ribbon blenders, blade blenders, V-shaped blenders,
batch mixers, or the like. A preferred blender is one that does not
excessively shear the GA particles, the metallic secondary shell,
or SAP. Depending on the type of equipment used, the two main
components and any optional components are added to the mixing
vessel either sequentially or simultaneously and mixing is carried
out until a uniformly blended product is formed.
[0065] With this gel-forming composition, output gasses are
drastically reduced and heat is safely and effectively produced, in
the absence of oxygen for activation and largely without a hydrogen
gas byproduct. In some embodiments, it has been found that between
90-100% of hydrogen gas byproduct has been suppressed or inhibited
as compared to if the secondary shell were not included in the
gel-forming composition.
[0066] In other embodiments of this composition, as a result of the
net inhibition of hydrogen gas, other improvements are provided.
For example, typical Mg--Fe alloy reactions with water produce a
very "metallic odor" as the human olfactory sense can detect the
hydrogen gas as a metal smell. Typical Mg--Fe alloy reactions with
water produce a very "metallic odor," which the human olfactory
senses can discern. This odor, while non-toxic, can be very
offensive to certain people, especially in the presence of food.
The eating experience is both taste and odor related, so an
offensive odor can ruin an eating experience. While food and eating
is one example, the benefits of preventing such metallic odors
provides a number of other benefits and a broader range of
potential uses of the underlying compositions. Certain embodiments
of this composition resolve this problem by preventing the metallic
odor from originating, and by absorbing any other odors into the
hydrogel formed by the SAP.
[0067] In other embodiments of this composition, to reduce or
inhibit the "metallic odor" of the Mg--Fe alloy reaction, activated
carbon is used with the composition as an odor absorber. While the
activated carbon may struggle, in certain embodiments, to absorb
hydrogen gas byproduct, adding activated carbon to the composition
unexpectedly interacts with the "push-pull" or "tug-of-war" between
electrons of the exothermic reaction so that the orbital shells and
the hydrogen bonding forces work with and against the SAP gel
matrix. In this regard, the SAP's ability to buffer, control,
lengthen and make predictable the heat profiles can be affected by
adding activated carbon. Surprisingly, the addition of activated
carbon helps make the exothermic reaction more efficient and longer
yield with an overall higher caloric output. The activated carbon
can be present in an amount of about 2 to 25% of the
composition.
[0068] Activated carbon can include a combination of graphite
materials, other carbon powders in various particle sizes. In
general, activated carbon forms contemplated herein are
electrically conductive forms of activated carbon. Using
combinations of some or all of these modifiers to the electrical
interactions of the gel-forming composition, is particularly
advantageous as to overall efficiency of the exothermic reaction.
Specifically, as the magnetic qualities of the conductive mineral
interact with the above mention electrical/hydrogen bond struggle
between the SAP and the alloy.
[0069] In other embodiments, an expandable, exothermic composition
is disclosed using Magnetite (Fe.sub.3O.sub.4) in combination with
one or more of the galvanic alloy particles and SAP embodiments
described in this disclosure. Using Magnetite is particularly
advantageous since when activated with an aqueous solution, an
exothermic reaction can be generated having a unique heat curve
(e.g., can generate heat a longer duration of time and/or at higher
temperatures) without sacrificing heat output duration.
[0070] The activating solution can be generally an aqueous
solution, such as water. It is also important to note that either
the gel-forming composition or the activating solution contains at
least one electrolyte, which assists in the electrochemical process
that is needed to initiate the exothermic reaction. As used herein,
the term "electrolyte" means a substance containing free ions that
is electrically conductive. Electrolyte solutions are usually ionic
solutions and commonly exist as solutions of acids, bases or salts.
Salts when placed in an aqueous solvent such as water dissociate
into their component elements. Examples of preferred electrolytes
include potassium chloride, sodium chloride and calcium
chloride.
[0071] The particulate gel-forming composition is tested by
measuring expansion volume and rate, as well as heat production and
retention. A particulate gel-forming composition is considered
optimal if it expands (volume/volume) at least two fold, and
preferably five fold or even ten fold. It is considered to be
"efficient" if it is capable of achieving a temperature of at least
105.degree. F. and maintaining a temperature of at least
100.degree. F. for one hour.
[0072] In one embodiment, magnesium-iron particles can be prepared
by mixing together 2-20% by weight iron with 80-98% by weight
magnesium in a hermetically sealed ball mill.
[0073] In one embodiment, the exothermic particulate gel-forming
composition has an absorption capacity of greater than 400 g/g.
[0074] In one embodiment, the blended mixture is formed by mixing a
weight ratio of 20:1 to 5:1 galvanic alloy particles to super
absorbent polymer. In other embodiments, the mixture is formed by
mixing a weight ratio of approximately 1:1 galvanic alloy particles
to super absorbent polymer. In other embodiments, the mixture is
formed by mixing a weight ratio of 20:1 to 5:1 super absorbent
polymer to galvanic alloy particles.
[0075] Air is evacuated with an inert dry gas prior to milling.
Milling continues at or near room temperature (e.g., 15 to
50.degree. C.) until the product is uniform. The galvanic alloy
product can be tested for its ability to react when contacted with
saline solution (e.g., 0.5 to 10% sodium chloride) by measuring a
loss in weight, primarily due to the emission of water vapor.
[0076] In frequent embodiments contemplated herein, the composition
is adapted to provide for minimal or approximately zero gases to be
produced or released from the composition (referring to the
reacted, reacting, formed, gel/foam, expanding or expanded,
exothermic, etc. composition) during or otherwise as a result of
the exothermic reaction. In frequently included embodiments, over
at or about 40%, over at or about 45%, over at or about 50%, over
at or about 55%, over at or about 60%, over at or about 65%, over
at or about 70%, over at or about 75%, over at or about 80%, over
at or about 85%, over at or about 90%, or over at or about 93%, or
over at or about 95% of gases produced by the exothermic reaction
are suppressed and not released from the composition (again,
referring to the reacted, reacting, formed, gel/foam, expanding or
expanded, exothermic, etc. composition) during or otherwise as a
result of the exothermic reaction.
Hydrogen Byproduct Sequestration
[0077] In another embodiment, GA particles can be blended or mixed
with super absorbent polymers and a permanganate or ferrate
oxidant, such as lithium permanganate, sodium permanganate,
potassium permanganate, lithium ferrate, sodium ferrate, or
potassium ferrate, to form a homogenous mixture. In this regard, a
safe, self-heating composition based on an oxidation reaction of GA
particles such as Mg--Fe is disclosed for oxidizing or eliminating
the hydrogen within the composition before the hydrogen gas
byproduct can escape. The gel-forming composition can be activated
in the absence of air upon contact with an activator solution, such
as an aqueous electrolyte solution such as water or saline
solution, as previously described.
[0078] Adding a permanganate or ferrate oxidant such as potassium
permanganate or potassium ferrate to the GA and SAP mixture results
in an oxygen source capable of combining with the hydrogen released
by the Mg--Fe alloy, before it can convert to hydrogen gas and
escape. In turn, during the reaction, water and hydrogen peroxide
(H.sub.2O.sub.2) can be produced, which in turn feeds back into
supplying the Mg--Fe alloy with a source of water to aide in its
oxidation-reduction reaction. Hydrogen peroxide ultimately breaks
down in this embodiment into water and another source of oxygen
molecules. In other words, H.sub.2 gas byproduct can be captured
and converted into water. While potassium permanganate or potassium
ferrate may be preferred, other reducible species can be used
within the confines of this disclosure.
[0079] In certain embodiments of this composition, using such
oxidants with the gel may result in a purple stain or discoloration
attributable to, for example, potassium permanganate. For certain
applications, such as with warming of food, this could be a
prohibitive byproduct because the food container may contacts a
permeable pouch and the staining agents would transit out of the
permeable pouch onto the food container and thus to the hands of
the person eating the food. However, this discoloration and
staining can be resolved by the gellation of the composition. For
example, a rubber-like, thick hydrogel that is exhibited in certain
embodiments can sequester liquids before they stain or discolor the
surrounding material. The transfer of the discolored solution can
then be reduced or eliminated since the staining agents are
"trapped" or sequestered by the gel. At the same time, the oxygen
generated by these reducible species can flow or "bubble through"
the gel allowing recombination with free hydrogen molecules, which
can take place within the gel.
[0080] The composition and activation by the liquid activator can
take place inside a sealed container to permit time for any
staining agent to be absorbed and sequestered the gel-forming
composition. In certain embodiments, one or more layers of the
container may optionally be permeable whereas others may optionally
be impermeable.
[0081] In certain embodiments, the heat generated within the
container expands the container due to the production of air and
the outflow of water vapor. Accordingly, the container must be
vented to outside atmospheric pressure. This venting can occur via
a panel of permeable material such as non-woven (or woven) fabric,
a perforated plastic cover, or the like. This permeable layer may
be disposed over a chamber where the composition comes into contact
with the aqueous solution. In order to further delay any leakage of
the staining solution, a layer of water-soluble film or coating may
also be applied to the inner side of the permeable layer
immediately adjacent the composition. A non-limiting example of
water soluble material can be polyvinyl alcohol (PVA or PVOH), but
any water-soluble coating or film can be used as needed or
required. In other embodiments, the container can include a
steam-pressure valve. These "valves" can vent steam or hot air
pressure at a predetermined level. This level of delay is, in
certain embodiments, time-programmed to ensure that all liquid
staining agents are sequestered.
[0082] By delaying the venting of steam and heated byproduct gasses
from the sealed container, further mixing and combining can occur
as to the free oxygen introduced by the reducible species reference
above and the free hydrogen produced by the oxidation of the GA
alloys. In turn, hydrogen byproducts can be further eliminated.
Additionally, in certain embodiments, as the heat and wetness of
the gel and steam permeate the water-soluble coating, it may
quickly dissolve before substantial pressure can build within the
container. In turn, the pressure can be released through the
permeable layer. This delay can also ensure that all free hydrogen
gas is removed.
An Exothermic Gel With No Hydrogen Gas Byproduct
[0083] In another embodiment, a catalyst for peroxide decomposition
can be blended or mixed with a buffering agent, such as the
aforementioned SAP, to form a mixture such as a powder mixture that
is uniform or otherwise homogenous. When the catalyst is combined
with the peroxide decomposition and the buffering agent, an
exothermic reaction can be caused that imparts no hydrogen gas
byproduct. Other buffering agents are contemplated for use with the
composition, including particles from blended compressed sponge,
clay particles, and other synthetic and modified natural materials.
Some synthetic superabsorbent material polymers contemplated for
use with the composition as a buffering agent, including the alkali
metal and ammonium salts of poly(acrylic acid) and poly(methacrylic
acid), poly(acrylamides), poly(vinyl ethers), maleic anhydride
copolymers with vinyl ethers and alpha-olefins, poly(vinyl
pyrrolidone), poly(vinylmorpholinone), poly(vinyl alcohol), and
mixtures and copolymers thereof. However, the composition is not so
limited and other superabsorbent materials contemplated for use
with the composition include other natural and modified natural
polymers, such as hydrolyzed acrylonitrile-grafted starch, acrylic
acid grafted starch, methyl cellulose, chitosan, carboxymethyl
cellulose, hydroxypropyl cellulose, and certain natural gums, such
as alginates, xanthan gum, locust bean gum and so forth.
[0084] The amount and characteristics of the buffering agent for
use with the catalyst for peroxide decomposition can be selectively
varied to control and/or stabilize the exothermic reaction
associated with the composition. The buffering agent may also be
selectively varied to adjust the caloric value output of the
composition at a higher or lower rate by suppressing, for example,
a carbonate solution with, for example, a magnesium sulfate. In
turn, this affects the mechanism by which the composition reacts so
that hydrogen peroxide decomposition is capable of flattening. This
is particularly advantageous as it renders decomposition more
efficient since it has also been discovered that rendering a stable
exothermic reaction more inefficient or unstable is one approach to
control or modifying output of the reaction.
[0085] The exothermic, expandable composition in these embodiments
can be activated upon contact with an activator solution containing
a peroxide, e.g. hydrogen peroxide (H.sub.2O.sub.2). For example, a
peroxide decomposition catalyst can be blended with SAP and
activated with hydrogen peroxide to produce an exothermic reaction.
The peroxide decomposition catalyst can be any peroxide
decomposition catalyst suitable for mixing with SAP or one or more
other buffering agents. For example, the peroxide decomposition
catalyst can be manganese oxide, a ferric salt such as ferric
chloride, or an enzyme such as catalase.
[0086] In certain embodiments, encapsulation of the catalyst can
affect the curve of heat output, delay or prolong the reaction,
based on solubility of the encapsulant. Other approaches to
affecting the heat output may include varying the catalysts,
including manganese oxide (MnO.sub.2), zinc oxide (ZnO), copper
oxide, PhO.sub.2, lead dioxide, red iron (III) oxide, peroxidase
enzymes, potassium iodide, ferric chloride, or the like.
[0087] This composition is particularly advantageous as the
exothermic reaction associated with the composition is
long-lasting, safe, controlled, and the activator solution has a
much lower freezing point versus saline solution or water. This is
particularly useful in operating environments where temperatures
can be substantially reduced such as higher altitudes or sub-zero
conditions. Preferably, 35% weight hydrogen peroxide can be used
with a freezing point of -31.degree. C., however, other weight
percentages can be used as needed or required. Moreover, because
the reaction is catalytic, the presence of the peroxide
decomposition catalyst can be minimized in the SAP mixture or
mixture with one or more other buffering agents. In one preferred
embodiment, a homogeneous mixture of manganese oxide and SAP can be
treated with a peroxide solution to generate an exothermic reaction
that produces only water and oxygen gas.
[0088] The gel-forming compositions of the present disclosure are
useful because they form an expanding gel or foam matrix when
hydrated, and create a balance between energy release and energy
governance. In certain embodiments, this is brought about by the
relationship between the SAP and other active ingredients in the
herein disclosed compositions. Though not wishing to be bound by
any theory of operation, the SAP absorbs the aqueous solution
rapidly, which limits the reaction potential of the remaining
ingredients of the composition. A controlled reaction then ensues
as moisture is transferred from the gel component to the remaining
component(s). This reaction liberates heat that is transferred back
into the gel that stores the heat rather than letting it escape
into the air in the form of heated gases. This synergistic heat
storage and distribution system provides a beneficial effect for
commercial applications such as medical, therapeutic and beauty
treatments. Since the gel-forming particles expand as they are
hydrated, they can be incorporated into any of a number of
different apparatuses and as they swell, they expand where desired,
which can be used to create an even blanket of exothermic gel,
thereby maximizing surface area contact and eliminating areas of
non-uniform heat. The peroxide decomposition rate can be modified,
for example, by sodium carbonate solution additions and variations
and relatively high concentrations of magnesium in salt or ionic
form, for example, magnesium sulfate.
[0089] In the examples that follow, the conditions such as weight
ratios, mixing times, and other data points can easily be optimized
for the particular intended use. For example, in a consumer
applications, it is often desirable to provide a composition that
achieves a higher temperature than for a medical product intended
to contact the skin.
EXAMPLE 1
MgFe Embodiment With Non-Suppressed Hydrogen Gas
[0090] In one embodiment, galvanic alloy materials include 0.5
grams of MgFe and 0.5 grams SA60S. The galvanic alloy and SAP
(SA60S) mixture is placed in the test tube and 5 grams of 3% saline
solutions is added. A stopper is positioned that forces gases
expelled by the exothermic reaction to pass through the tubing into
a completely full water flask. Water is displaced into a beaker.
The amount of water displaced by the gas evolution was recorded,
with test 1 showing 303.2 grams of water displaced, test 2 showing
305.6 grams of water displaced, test 3 showing 298.7 grams of water
displaced, test 4 showing 301.2 grams of water displaced, and test
5 showing 304. 6 grams of water displaced.
EXAMPLE 2
[0091] A. Non-Milled MnO.sub.2 Composition Mixture, Hydrogen Gas
Suppressed
[0092] In one embodiment, galvanic alloy particles, SAP, and
MnO.sub.2 are prepared by being blended together in a blending
apparatus to form a powder mixture. The materials include 0.5 grams
of MgFe, 0.5 grams SA60S, and 0.5 grams MnO.sub.2. The powder
mixture is placed in the test tube and 5 grams of 3% saline
solutions is added. A stopper is positioned that forces gases
expelled by the exothermic reaction to pass through the tubing into
a completely full water flask. Water is displaced into a beaker.
The amount of water displaced by the gas generation was recorded,
with approximately 62.9% gas generated versus non-suppressed
Example 1, yielding approximately 37% gas suppression.
[0093] B. Milled MnO.sub.2 Composition Mixture, Hydrogen Gas
Suppressed
[0094] In one embodiment, galvanic alloy particles and SAP are
prepared by alloying MgFe with MnO.sub.2 using a high-speed ball
mill and combining it with the SAP (SA60S). The materials include
0.5 grams of MgFe/MnO.sub.2, alloy blended with 0.5 grams SA60S.
The MgFe/MnO.sub.2 alloy is blended with the SAP. The blended
MgFe/MnO.sub.2 alloy with SAP is placed in the test tube and 5
grams of 3% saline solutions is added. A stopper is positioned that
forces gases expelled by the exothermic reaction to pass through
the tubing into a completely full water flask. Water is displaced
into a beaker. The amount of water displaced by the gas generation
is recorded. Results show a majority of gas produced by the
reaction to be suppressed.
EXAMPLE 3
[0095] KMnO.sub.4 Potassium Permanganate Composition Mixture,
Hydrogen Gas Suppressed
[0096] In one embodiment, galvanic alloy particles, SAP, and
KMnO.sub.4 are prepared by being blended together in a blending
apparatus to form a powder mixture. The galvanic alloy materials
include 0.5 grams of MgFe, 0.5 grams SA60S, and 0.5 grams
KMnO.sub.4. The powder mixture is placed in the test tube and 5
grams of 3% saline solutions is added. A stopper is positioned that
forces gases expelled by the exothermic reaction to pass through
the tubing into a completely full water flask. Water is displaced
into a beaker. The amount of water displaced by the gas generation
was recorded, with approximately 6.8% gas generated versus Example
1, yielding approximately 93.2% gas suppression.
[0097] It will be understood that many additional changes in the
details, materials, steps and arrangement of parts, which have been
herein described and illustrated to explain the nature of the
invention, may be made by those skilled in the art within the
principle and scope of the invention as expressed in the appended
claims.
[0098] The definitions of the words or elements of the following
claims are, therefore, defined in this specification to not only
include the combination of elements which are literally set forth.
It is also contemplated that an equivalent substitution of two or
more elements may be made for any one of the elements in the claims
below or that a single element may be substituted for two or more
elements in a claim. Although elements may be described above as
acting in certain combinations and even initially claimed as such,
it is to be expressly understood that one or more elements from a
claimed combination can in some cases be excised from the
combination and that the claimed combination may be directed to a
sub combination or variation of a subcombination(s).
[0099] Insubstantial changes from the claimed subject matter as
viewed by a person with ordinary skill in the art, now known or
later devised, are expressly contemplated as being equivalently
within the scope of the claims. Therefore, obvious substitutions
now or later known to one with ordinary skill in the art are
defined to be within the scope of the defined elements. The claims
are thus to be understood to include what is specifically
illustrated and described above, what is conceptually equivalent,
what can be obviously substituted and also what incorporates the
essential idea of the embodiments.
[0100] What has been described above includes examples of one or
more embodiments. It is, of course, not possible to describe every
conceivable combination of components or methodologies for purposes
of describing the aforementioned embodiments, but one of ordinary
skill in the art may recognize that many further combinations and
permutations of various embodiments are possible. Accordingly, the
described embodiments are intended to embrace all such alterations,
modifications and variations that fall within the spirit and scope
of the appended claims. Furthermore, to the extent that the term
"includes" is used in either the detailed description or the
claims, such term is intended to be inclusive in a manner similar
to the term "comprising" as "comprising" is interpreted when
employed as a transitional word in a claim.
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