U.S. patent application number 10/947975 was filed with the patent office on 2008-01-17 for lead-free electric match compositions.
Invention is credited to Blaine W. Asay, James R. Busse, Michael A. Hiskey, Darren Naud, Steven F. Son.
Application Number | 20080011398 10/947975 |
Document ID | / |
Family ID | 31186874 |
Filed Date | 2008-01-17 |
United States Patent
Application |
20080011398 |
Kind Code |
A9 |
Naud; Darren ; et
al. |
January 17, 2008 |
Lead-free electric match compositions
Abstract
An electric match including nanoscale particulates of an
energetic material and a binder is provided. The energetic material
can be a nanoscale thermite metal/metal oxide mixture, a nanoscale
intermetallic material mixture, or a nanoscale fuel and oxidant
mixture.
Inventors: |
Naud; Darren; (Los Alamos,
NM) ; Son; Steven F.; (Los Alamos, NM) ;
Hiskey; Michael A.; (Los Alamos, NM) ; Busse; James
R.; (Los Alamos, NM) ; Asay; Blaine W.; (Los
Alamos, NM) |
Correspondence
Address: |
Bruce H. Cottrell;Los Alamos National Laboratory
LC/IP, MS A187
Los Alamos
NM
87545
US
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20060060272 A1 |
March 23, 2006 |
|
|
Family ID: |
31186874 |
Appl. No.: |
10/947975 |
Filed: |
September 23, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10208696 |
Jul 29, 2002 |
|
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10947975 |
Sep 23, 2004 |
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Current U.S.
Class: |
149/37 |
Current CPC
Class: |
F42B 3/198 20130101;
F42B 3/11 20130101; C06C 9/00 20130101; C06C 15/00 20130101; C06B
33/00 20130101; C06B 45/14 20130101; F42B 3/128 20130101 |
Class at
Publication: |
149/037 |
International
Class: |
C06B 33/00 20060101
C06B033/00 |
Goverment Interests
STATEMENT REGARDING FEDERAL RIGHTS
[0001] This invention was made with government support under
Contract No. W-7405-ENG-36 awarded by the U.S. Department of
Energy. The government has certain rights in the invention.
Claims
1. An electric match composition comprising nanoscale particulates
of an energetic material and a binder.
2. The electric match composition of claim 1 wherein said binder is
nitrocellulose.
3. The electric match composition of claim 1 wherein said energetic
material is selected from the group consisting of a nanoscale
thermite metal/metal oxide mixture, a nanaoscale intermetallic
material mixture and a nanoscale fuel and oxidant mixture.
4. The electric match composition of claim 3 wherein said nanoscale
thermite metal/metal oxide mixture includes a metal selected from
the group consisting of aluminum, boron, lanthanum, magnesium,
tantalum, titanium, yttrium and vanadium and a metal oxide selected
from the group consisting of silver oxide, boron oxide, bismuth
oxide, copper oxide, cobalt oxide, iron oxide, manganese oxide,
molybdenum trioxide, nickel oxide, silicon oxide, tin oxide,
tantalum oxide, titanium oxide, tungsten oxide and vanadium
oxide.
5. The electric match composition of claim 3 wherein said nanoscale
thermite metal/metal oxide mixture is selected from the group
consisting of aluminum and copper oxide, aluminum and iron oxide,
aluminum and molybdenum trioxide, and aluminum and tungsten
oxide.
6. The electric match composition of claim 3 wherein said nanoscale
thermite metal/metal oxide mixture is of aluminum and molybdenum
trioxide.
7. The electric match composition of claim 3 wherein said
intermetallic material mixture is selected from the group
consisting of titanium boron and nickel aluminum.
8. The electric match composition of claim 3 wherein said nanoscale
fuel and oxidant mixture includes a metal fuel selected from the
group consisting of aluminum, boron, magnesium, carbon and silicon
and an oxidant including a cation selected from the group
consisting of potassium sodium and ammonium and an anion selected
from the group consisting of perchlorate, chlorate and nitrate.
9. The electric match composition of claim 1 wherein said nanoscale
particulates have a mean size of from about 40 nm to 500 nm in
smallest dimension.
10. The electric match composition of claim 1 wherein said match is
lead-free.
11. An electric match comprising a match head coated with an
electric match composition including nanoscale particulates of an
energetic material and a binder.
12. The electric match of claim 11 wherein said energetic material
is selected from the group consisting of a nanoscale thermite
metal/metal oxide mixture, a nanoscale intermetallic material
mixture and a nanoscale fuel and oxidant mixture.
13. The electric match of claim 11 wherein said binder is
nitrocellulose.
14. The electric match of claim 11 wherein said match head includes
a first layer coating including nanoscale particulates of an
energetic material and a first binder, a second layer coating
including secondary pyrotechnic composition and a second binder,
and a protective waterproof topcoat polymer layer.
15. The electric match of claim 14 wherein said first binder and
second binder are nitrocellulose.
16. The electric match of claim 14 further including a layer of
nitrocellulose between said second layer coating and said
protective topcoat layer.
17. The electric match of claim 14 further including a layer of
nitrocellulose between said first layer coating and said second
layer coating and a layer of nitrocellulose between said second
layer coating and said protective topcoat layer.
18. The electric match of claim 12 wherein said nanoscale thermite
metal/metal oxide composition includes a metal selected from the
group consisting of aluminum, boron, lanthanum, magnesium,
tantalum, titanium, yttrium and vanadium and a metal oxide selected
from the group consisting of silver oxide, boron oxide, bismuth
oxide, copper oxide, cobalt oxide, iron oxide, manganese oxide,
molybdenum oxide, nickel oxide, silicon oxide, tin oxide, tantalum
oxide, titanium oxide, tungsten oxide and vanadium oxide.
19. The electric match of claim 12 wherein said nanoscale thermite
metal/metal oxide mixture is selected from the group consisting of
aluminum and copper oxide, aluminum and iron oxide, aluminum and
molybdenum trioxide, and aluminum and tungsten oxide.
20. The electric match of claim 12 wherein said nanoscale thermite
metal/metal oxide mixture is aluminum and molybdenum trioxide.
Description
FIELD OF THE INVENTION
[0002] The present invention relates to electric match
compositions, preferably lead-free electric match compositions and
to electric matches, preferably lead-free electric matches.
BACKGROUND OF THE INVENTION
[0003] Electric matches are used in the field of pyrotechnics to
initiate devices by electrical means rather than by fuses. Fuses
have the disadvantage of burning with a long delay before igniting
a pyrotechnic device. Electric matches can instantaneously fire a
device upon a user's command. In addition, electric matches can be
fired remotely at a safe distance.
[0004] Unfortunately, most current commercial electric match
compositions contain lead compounds, e.g., lead thiocyanate, lead
nitroresorcinate, lead oxides or lead picramate, which when burned,
vaporize to produce a lead-containing smoke. For commercial
pyrotechnic displays, such lead-containing smoke is a pollutant
causing detrimental exposure to a cast, crew and audience. The
reason that these lead-containing compounds are used as electric
match compositions is that only these mixtures have the required
thermal stability while being able to be initiated reliably by a
very low energy thermal stimulus, such as spark or resistive
heating.
[0005] A typical electric match head consists of an electrically
insulating substrate with copper foil cladding, similar to that
used for printed circuit boards. The size of the substrate is
generally approximately 0.4 inches long by 0.1 inches wide and 30
mils thick. The tip of the match has a small diameter nicrome wire
soldered across the edge of the match. Insulated wire leads
soldered at the base of the match provide the means of electrically
firing the nicrome wire to produce the initiating spark. The match
head is coated with the lead-based composition to produce the
spark-sensitive bead above the nicrome bridge wire. Normally, the
bead is coated with a second layer of composition of a metal fuel
such as a magnesium/aluminum alloy or titanium with potassium
perchlorate oxidizer. This secondary coat is generally necessary to
produce the hot sparks to initiate black powder (or other primers)
in pyrotechnic devices. Finally, the bead is generally coated with
a nitrocellulose lacquer to provide strength and water resistance.
Other similar match designs are well known.
[0006] After extensive and careful investigation, electric match
compositions have now been developed free of lead-containing
compounds.
SUMMARY OF THE INVENTION
[0007] To achieve the foregoing and other objects, and in
accordance with the purposes of the present invention, as embodied
and broadly described herein, the present invention provides an
electric match composition including nanoscale particulates of an
energetic material and a binder. Preferably, the electric match
composition is lead-free.
[0008] The present invention further provides an electric match
including a match head coated with an electric match composition
including nanoscale particulates of an energetic material and a
binder. Preferably, the electric match is lead-free.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 shows a schematic drawing of an electric match in
accordance with the present invention.
DETAILED DESCRIPTION
[0010] The present invention is concerned with lead-free electric
match compositions and preparation of lead-free electric
matches.
[0011] In the present invention, the electric match materials
include nanoscale energetic materials such as nanoscale thermite
material mixtures, nanoscale intermetallic material mixtures, and
nanoscale fuel and oxidant mixtures, preferably nanoscale thermite
material mixtures. Such nanoscale energetic materials are easily
ignited, have good energy content and produce high temperature
products. Also, the reaction rate is generally very rapid for
nanoscale energetic materials such as nanoscale thermite materials
and the reaction rate can be further tuned by control of the
particle size.
[0012] The thermite material mixtures used in the present invention
are metal/metal oxide compositions including a metal selected from
the group consisting of aluminum, boron, lanthanum, magnesium,
tantalum, titanium, yttrium and vanadium and a metal oxide selected
from the group consisting of silver oxide, boron oxide, bismuth
oxide, copper oxide, cobalt oxide, iron oxide, manganese oxide,
molybdenum oxide, nickel oxide, silicon oxide, tin oxide, tantalum
oxide, titanium oxide, tungsten oxide and vanadium oxide. Among the
suitable thermite material mixtures can be included aluminum and
silver oxide, aluminum and boron oxide, aluminum and bismuth oxide,
aluminum and cobalt oxide, aluminum and copper oxide, aluminum and
iron oxide, aluminum and manganese oxide, aluminum and molybdenum
oxide, aluminum and niobium oxide, aluminum and nickel oxide,
aluminum and palladium oxide, aluminum and silicon oxide, aluminum
and tin oxide, aluminum and tantalum oxide, aluminum and titanium
oxide, aluminum and vanadium oxide, aluminum and tungsten oxide,
boron and copper oxide, boron and iron oxide, boron and manganese
oxide, boron and nickel oxide, boron and silicon oxide, boron and
tin oxide, boron and tantalum oxide, boron and titanium oxide,
boron and vanadium oxide, boron and tungsten oxide, lanthanum and
silver oxide, lanthanum and copper oxide, lanthanum and iron oxide,
lanthanum and manganese oxide, lanthanum and palladium oxide,
lanthanum and tungsten oxide, magnesium and boron oxide, magnesium
and copper oxide, magnesium and iron oxide, magnesium and manganese
oxide, magnesium and silicon oxide, tantalum and silver oxide,
tantalum and copper oxide, tantalum and iron oxide, tantalum and
tungsten oxide, titanium and boron oxide, titanium and copper
oxide, titanium and iron oxide, titanium and manganese oxide,
titanium and silicon oxide, yttrium and copper oxide, yttrium and
iron oxide, yttrium and manganese oxide, yttrium and molybdenum
oxide, yttrium and nickel oxide, yttrium and palladium oxide,
yttrium and tin oxide, yttrium and tantalum oxide, yttrium and
vanadium oxide, yttrium and tungsten oxide, zirconium and boron
oxide, zirconium and copper oxide, zirconium and iron oxide,
zirconium and manganese oxide, and zirconium and silicon oxide.
Preferably the thermite material mixtures are aluminum and
molybdenum oxide, aluminum and iron oxide, aluminum and copper
oxide and aluminum and tungsten oxide. The materials can be added
in about stoichiometric amounts, although variations from
stoichiometric amounts can be used as well.
[0013] The nanoscale intermetallic material mixtures used in the
present invention may be material mixtures such as aluminum with
nickel, cobalt, copper, iron, molybdenum, niobium, palladium,
titanium, or zirconium, alloys of titanium with boron, nickel,
cobalt and iron, zirconium boron, and hafnium boron. Preferably the
nanoscale intermetallic material mixtures are titanium boron or
nickel aluminum.
[0014] The nanoscale fuel and oxidant mixtures used in the present
invention may include a metal such as aluminum, boron, magnesium
carbon, or silicon and an oxidant with a cation such potassium,
sodium or ammonium and an anion such as nitrate, chlorate,
perchlorate or peroxide. Particular fuel and oxidant mixtures may
include: aluminum and ammonium perchlorate; aluminum and ammonium
chlorate; aluminum and ammonium nitrate; and, aluminum and
potassium nitrate. Preferably, the nanoscale fuel and oxidant
mixtures are aluminum and ammonium perchlorate, aluminum and
ammonium chlorate, or aluminum and ammonium nitrate.
[0015] As mentioned, the energetic materials of the electric match
composition are nanoscale size materials. Generally, the materials
are particulates with predominant size distributions of from about
10 nm to 1000 nm in smallest dimension, e.g., diameter, thickness
and the like, preferably from about 20 nm to 500 nm, more
preferably from about 30 nm to 300 nm. Within the particulates, it
is not uncommon to find a minor amount of particles significantly
outside the mean particle size, e.g., some particles of as large as
a micron can be present without detrimental effect. Size
distribution within a particular sample of material is another
factor. Broader size distributions may be preferable to provide
easier ignition and increased spark generation for consistent
ignition oif the secondary pyrotechnic composition.
[0016] The binder for the nanoscale energetic materials can be any
standard material used for binding paticles together. Preferably,
the binder is nitrocellulose, but other binders are well known to
those skilled in the art. In the electric matches, a nitrocellulose
binder is also preferred for binding secondary pyrotechnic
composition materials together within the match head as well.
[0017] A protective topcoat layer of a suitable waterproof polymer
is over the entire match head. Suitable waterproof polymers can
include polymers and copolymers of vinyl based materials such as
polyvinyl chloride, polyvinyl acetate, polystyrene, polymethyl
methacrylate, polyacrylonitrile and the like. Especially preferred
is a copolymer of polyvinyl chloride, polyvinyl acetate and
2,3-epoxypropyl methacrylate.
[0018] FIG. 1 shows an electric match head in accordance with the
present invention. Match head 10 includes standard match parts such
as a high resistance bridgewire 3, electrical insulator 5 with
conductive foil cladding 4 and wire leads 6 soldered to the foil
cladding 4. Primary coating layer 7 including the nanoscale
particulates of an energetic material and a binder is on bridgewire
3. Over primary coating layer 7 is secondary pyrotechnic
composition layer 2. Finally, a protective waterproof topcoat
polymer layer 1 is over secondary pyrotechnic composition layer
2.
[0019] While not as preferred as a protective waterproof topcoat
polymer layer over the entire match head, nanoscale particulates
may be coated with a fluorosilane to provide protection from water
and oxygen.
[0020] The present invention is more particularly described in the
following example which is intended as illustrative only, since
numerous modifications and variations will be apparent to those
skilled in the art.
EXAMPLE 1
[0021] A bare electric match head was dipped into a sample
composition for the primary layer. The sample composition had been
diluted with ethyl acetate containing 0.3 weight percent FC 430
(from 3M) surfactant. The primary layer included about 6 milligrams
(mg) of a mixture of 9 percent by weight of 13.5 percent nitrogen
content nitrocellulose (NC), and a 91 percent by weight of a
mixture of 121 nm nanosize aluminum (from Technanogy, Inc., Irvine
Calif.), 132 nm nanosize aluminum (from Technanogy, Inc., Irvine
Calif.) and a nanoscale MoO.sub.3 material obtained from Climax
Corp. having a sheet thickness of about 15 nm. Nanoscale aluminum
(45 percent by weight) and nanoscale molybdenum trioxide (55
percent by weight) had been previously mixed by sonication to
obtain the desired thermite metal/metal oxide mixture. After the
primary layer, a thin barrier coating of nitrocellulose was
deposited by dipping the match head into a nitrocellulose/ethyl
acetate lacquer.
[0022] A secondary pyrotechnic composition included 56 percent by
weight finely ground potassium perchlorate, 27 percent by weight 12
micron black aluminum, 8 percent by weight titanium (80-100 mesh),
0.3 percent by weight superfine iron oxide, 8.7 percent by weight
nitrocellulose and sufficient ethyl acetate solvent to form a
viscous slurry. The match head was dipped into this secondary
material several times with intermediate drying to build up the
quantity of secondary pyrotechnic composition, followed again by a
protective coat of nitrocellulose using the same
nitrocellulose/ethyl acetate lacquer as with the primary layer.
[0023] A protective waterproof topcoat polymer layer was finally
deposited onto the match head by dipping each match head into a
composition of a copolymer of polyvinyl chloride, polyvinyl acetate
and 2,3-epoxypropyl methacrylate dissolved in a mixture of methyl
ethyl ketone and toluene.
[0024] The resultant electric match head was found to have
reasonable mechanical strength.
EXAMPLE 2
[0025] Aging tests were conducted on the final electric match
heads. The protective topcoating had been used to keep moisture
from contact with the nanosize aluminum. The final electric match
heads were submerged in water for three weeks and continued to
perform reliably.
EXAMPLE 3
[0026] Impact tests (2.5 kg weight onto bare anvil) were conducted
on the lead-free matches by placing the match head sample between
two sheets of thick paper card stock and allowing a 1-kg drop
weight to fall onto the sample. It was determined from twenty
samples that the 50% probability of ignition (as described by Paine
et al., Inorg. Chem., vol. 38, pp. 3738-3743 (1999)) was
approximately 56 kg-cm. Identical tests on seven other commercially
available electric matches of standard construction and performance
gave results that ranged between 9 kg-cm and 23 kg-cm.
EXAMPLE 4
[0027] Thermal ignition tests on these lead-free matches were
performed by placing the match heads in a heated block and
measuring time to initiation. The match heads did not undergo
initiation within five seconds when placed in a 300.degree. C.
environment. Comparatively, five commercially available electric
matches of standard construction and performance showed initiation
in five seconds at temperatures between 215.degree. C. and
280.degree. C.
[0028] From all these results, it was concluded that lead-free
match heads in accordance with the present invention, had
properties comparable or exceeding those of commercially available
electric matches of standard construction and performance.
[0029] Although the present invention has been described with
reference to specific details, it is not intended that such details
should be regarded as limitations upon the scope of the invention,
except as and to the extent that they are included in the
accompanying claims.
* * * * *