U.S. patent number 3,774,022 [Application Number 04/468,231] was granted by the patent office on 1973-11-20 for packaged chemiluminescent material.
This patent grant is currently assigned to TRW, Inc.. Invention is credited to Bernard Dubrow, Eugene Daniel Guth.
United States Patent |
3,774,022 |
Dubrow , et al. |
November 20, 1973 |
PACKAGED CHEMILUMINESCENT MATERIAL
Abstract
This invention relates to a packaged luminescent material, and
more particularly to a combined package of a chemiluminescent agent
as the "fuel," and an activating agent therefor, wherein the fuel
and activating agent are maintained in close association but
separated from each other by a barrier medium to prevent
interaction before the same is desired. When the barrier medium is
ruptured, or otherwise broken down, either deliberately or
unintentionally, a reaction occurs between the chemiluminescent
agent and the activating agent with the emission of visible light,
without, however, the generation of any appreciable amount of
heat.
Inventors: |
Dubrow; Bernard (Torrance,
CA), Guth; Eugene Daniel (Palos Verdes Peninsula, CA) |
Assignee: |
TRW, Inc. (Cleveland,
OH)
|
Family
ID: |
23858953 |
Appl.
No.: |
04/468,231 |
Filed: |
June 30, 1965 |
Current U.S.
Class: |
362/34; 102/336;
116/206; 273/DIG.24; 473/570; 89/1.52; 116/63P; 252/700 |
Current CPC
Class: |
F21K
2/06 (20130101); Y10S 273/24 (20130101) |
Current International
Class: |
F21K
2/00 (20060101); F21K 2/06 (20060101); F21v
009/16 () |
Field of
Search: |
;240/2.25 ;206/84
;102/37.8 ;252/188.3,301.2 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Quarforth; Carl D.
Assistant Examiner: Gittes; F. M.
Claims
We claim as our invention:
1. A packaged chemical light source comprising a constant
package
a first mass in said package of a chemiluminescent agent selected
from the group consisting of siloxenes, polysiloxenes, substitution
products of polysiloxenes and mixtures thereof;
a second mass in said package of an inorganic oxidizing agent,
and
a barrier inert to both masses and separating said respective
masses,
said barrier being readily breached to effect an admixing of said
masses and the resulting admixture when brought into contact with a
liquid selected from the group consisting of water, water-miscible
C.sub.1 -C.sub.5 alcohols and mixtures thereof reacting to produce
chemiluminescent light.
2. A packaged chemical light source as defined by claim 1,
wherein,
said oxidizing agent is a tetravalent cerium salt.
3. A source as defined by claim 1, wherein
said barrier is a thin, frangible synthetic plastic membrane.
4. A source as defined by claim 1, wherein
said barrier comprises two associated encapsulating membranes
forming separate compartments with the respective masses within the
respective compartments.
5. A source as defined by claim 1, wherein
said two membranes form inner and outer walls, one wholly within
the other.
6. A source as defined by claim 1, wherein
at least one of said masses includes water, and said barrier being
relatively water and moisture impervious.
7. A light source as defined by claim 1, wherein,
said barrier is constituted by plastic membranes separately
encapsulating the respective agents, and a rupturable outer casing
enclosing a plurality of said membrane encapsulated agents.
8. A light source as defined by claim 1, wherein,
said oxidizing agnet is in the form of a water gel containing an
inorganic oxidizing agent.
9. A light source as defined by claim 1, wherein,
the selected chemiluminescent agent is carried in a water gel.
10. A light source as defined by claim 1, wherein,
the selected chemiluminescent agent is distributed in and carried
by a water gel, and said oxidizing agent is an inorganic oxidizing
agent also distributed in and carried by a water gel.
11. A light source as defined by claim 10, wherein,
both of said water gels are maintained under gas pressure for
release and admixture of said gels.
12. A light source as defined by claim 1, wherein,
said package is in the form of a grenade having a detonator and
igniter.
Description
The term "chemiluminescence," is used herein to indicate the
ability to produce light as a direct result of chemical changes.
Since the process of light emission is purely an energy
transformation, it is deemed proper to apply the term
chemiluminescence to the luminescent phenomenon that originates
from chemical energy, viz., the transformation of the free energy
of a chemical reaction into light energy. Thus, if as a result of a
chemical reaction there is a shift of an electron to a higher
energy level of an atom or molecule, and this is accompanied by the
emission of light during the return of the electron to the ground
state level, this phenomenon may be regarded as due to a chemical
change, and in that case chemiluminescence is the only mechanism by
which the light has been emitted.
Chemiluminescence this differs from fluorescence in that the former
is excited by chemical energy while the latter is excited by
radiant energy. The demonstration of the validity of this point of
view is due mostly to Kautsky and his co-workers (Kautsky, H., et
al., Z. Physik, 9, 267 (1922); 31, 60 (1923); Trans. Faraday Soc.,
21, 591 (1926), who studied the phenomenon of chemiluminescence
caused by the rapid oxidation of "silikon," a mixture of siloxene
(Si.sub.6 H.sub.6 O.sub.3).sub.n and its reaction products. The
authors showed that in this system, the chemiluminescence was
attributable to the absorption of the reaction energy by the
unchanged molecules of the silikon which emitted this energy as
light. Fluorescence of the silikon could be induced under
conditions where chemiluminescence was completely absent. The two
sets of spectra were identical.
We have now found that the phenomenon of chemiluminescence can be
put to practical uses by so packaging the components, or reactants,
of a chemiluminescent system as to make it feasible to produce
chemiluminescent light, either deliberately by unskilled personnel,
or, for the purpose of detection inadvertently by hostile personnel
or equipment. In its simplest aspect, this invention relates to
packaged luminescent material comprising a chemiluminescent agent
and an activating agent associated in a system, but separated by
barrier means that prevent reaction between the components of the
system prior to the time desired for such reaction to occur, the
barrier means being capable of being broken down under such
circumstances as to cause an admixture of the components with a
resultant chemical reaction therebetween and an emission of
chemiluminescent light. The chemiluminescent agent can be in the
form of a liquid, a powder, or a dispersion of a powder in a fluid
or gel matrix. It is protected from chemical reaction with the air
or with extraneous constituents by its enclosure, or encapsulation,
in a protective material that serves as a part of the barrier means
between the chemiluminescent agent and the activating agent of the
two-component system is also contained within or protected by
barrier means in such manner that a prescribed quantity of the
activating agent can, on demand, be made to mix and react with the
chemiluminescent agent to produce light. Such light can be
reactivated if only partial reaction initially takes place between
the chemiluminescent agent and the activator, so long as means for
subsequent mixing are provided.
According to the prior art, chemiluminescent light cannot be
produced efficiently from systems which require two components
unless the components are mixed in controlled proportions and
handled by technically trained or experienced personnel. We have
now discovered means for utilizing a two-component chemiluminescent
system which requires controlled proportions of the two components
to be mixed for maximum efficiency in the production of emitted
light, but which does not require experienced or trained personnel
to effectuate the activation of the system. We have also discovered
a method for preparing and packaging chemiluminescent materials in
forms which have high utility, both for civilian and military
purposes.
In the preparation of packaged chemiluminescent material in
accordance with our invention, the following steps are employed in
combination:
1. Preparing the chemiluminescent agent and the activator
separately in the preferred or desired form for the intended
use;
2. Preparing aliquot portions of said forms of the chmiluminescent
agent and the activator;
3. Packaging the chemiluminescent agent and the activator in such
aliquot proportions and in association with each other but so
separated from one another that premature reaction therebetween
cannot occur, yet upon their reaction, or interaction, there is
produced a reaction product of a preferred composition for the
emission of chemiluminescent light; and
4. Actuating the release of chemiluminescent light by causing the
luminescent agent and the activator in said packaged form of the
system to become mixed.
In the practice of our invention, the package of the
chemiluminescent agent and of the activator can take various forms
both as to construction and design, including the following:
1. Coating either the chemiluminescent agent or the activator in a
desired form and packaging such coated material inside a second
coating or envelope which contains the other component of the
two-component system.
2. Packaging the chemiluminescent agent and the activator
separately within barrier means, or by the use of a barrier medium
therebetween, and associating together the separately packaged
agents, as by physical union of the separately packaged agents, or
by enclosure within a common barrier means; and
3. Packaging the chemiluminescent agent and the activator,
respectively, in a suitable form in relatively large containers or
tanks so arranged that the chemiluminescent agent and the activator
are in the proper proportions and/or can be metered in the proper
proportions for admixture and resultant emission of light.
In general, the barrier means above referred to are most suitably
in the form of films or membranes that envelop or encapsulate the
luminescent agent and activator, respectively, and that are not
only inert towards these components, but are, relatively water- and
moisture-impervious and are either fragile, frangible or of such
character as to be easily ruptured or broken down. In some cases,
as when the package takes the form of a grenade, the same explosive
force that disintegrates the enclosing shell also ruptures the
barrier media separating the chemiluminescent agent from the
activator and thus brings about a mixing of the reactants of the
two-component system that results in the emission of
chemiluminescent light.
The ehcmiluminescent agent preferably used in the package of our
invention is a polysiloxene (sometimes in the literature spelled
"siloxen"). When calcium silicide (CaSi.sub.2) is treated with
dilute hydrochloric acid (HCl), a "polymerized siloxane" of the
composition (Si.sub.6 O.sub.3 H.sub.6).sub.n is formed. This
compound, known as a polysiloxene is the parent substance for a
group of compounds of unusual properties.
Siloxene, itself, is not chemiluminescent, but it is a component of
silikon, which is herein used as the generic term for any
chemiluminescent mixture of siloxene, polysiloxenes and
substitution products of polysiloxenes. The term "Silicone" has
been used in the literature (Analytical Chemistry, Vol. 22, No. 5,
May 1950 (pp. 693-697) but since that is a commonly used term
denoting a now well-known series of polymeric R.sub.2 Si=O
compounds, we shall use the term silikon here.
The following example will serve to illustrate a preferred method
of making substituted polysiloxenes:
EXAMPLE
Two grams of powdered calcium silicide were mixed with 20 ml of
concentrated hydrochloric acid with stirring. When the temperature
subsided, an additional 10 ml of concentrated hydrochloric acid
were added with stirring and the resulting mixture was boiled for 5
minutes. The suspension of the product was diluted with 60 ml of
water and boiled for 5 minutes. The crude polysiloxene was
separated from the liquid on a funnel and washed successively with
approximately 5 ml each of water, ethyl alcohol and ether. This
procedure can be varied by those skilled in the art to cover a wide
range of conditions. The preparation is acceptable so long as the
product has the desired properties and the preparation can be
carried out safely.
Activating agents for activating the various polysiloxenes and
their substitution products are, in general, oxidizing agents, such
as the following:
Hydrogen peroxide
Potassium permanganate
Manganese peroxide
Chromic acid
Persulfuric acid
Mercurous nitrate
Mercuric nitrate
Ferric chloride
Ceric ammonium sulfate
Ceric ammonium nitrate
Ceric sulfate
Ceric oxide
Cerium nitrate
Potassium hexanitrate cerate
Uranyl nitrate
Uranyl acetate
Potassium ruthenate
Vanadium pentoxide
Chromium trioxide
Magnesium perchlorate
Most per- acids, such as perchloric acid, perboric acid,
persulfuric acid and the like can be employed, but we have found
that organic oxidizers, generally speaking, cannot be successfully
used to produce chemiluminescence from silikon.
In order to activate the chemiluminescent agent, water should be
added, or should be furnished by the chemiluminescent agent, the
inorganic oxidizing agent, or by both. An aqueous-type liquid, such
as a C.sub.1 to C.sub.5 alcohol, preferably methanol or ethanol can
be used in order to provide a medium in which the oxidizing agents
can diffuse rapidly into the siloxene particles, but water is
preferred. The water or other solvent appears not to enter into the
reaction, but only to make the reaction proceed.
While the chemiluminescent agent and/or the oxidizing agent can be
used in a solid state, we have found it advantageous to incorporate
either or both of the agents into a gel system. A gelling medium
which has been found suitable is Cab-o-sil M-5, manufactured by the
Cabot Corporation, but other types of gel-forming silicas than
Cab-o-sil can be used satisfactorily. Cab-o-sil is a fire-dry
pyrogenic silica with a particle size of 0.015 microns, a surface
area of 200 m.sup.2 /gm, and bulk density of 2.2 lb/ft.sup.3. If a
water gel is made up from any of these active silicas, the gel is
thixotropic, i.e., it thins down and flows when agitated, beaten or
otherwise submitted to a shearing action. Thus, although the gel
sets after mixing, the degree of set and the time after mixing at
which set occurs (both of which are functions of the percent solids
and the percent silica gel), the application of a shearing force
will cause the gel to flow. These properties are considered
advantageous for storage and application.
Preferably, the gels prepared from any of the suitable
chemiluminescent agents have a pH of about 1, due to traces of HCl
in the chemiluminescent agent, while the activator, or oxidizing
agent gels have a pH of about 6. Inasmuch as the chemiluminescent
agent works best in a specific environment, the ability of silica
gels, such as Cab-o-sil, to gel in an acid environment is an
important characteristic.
The principle which underlies the obtaining of the optimum results
from both agents in activated gels thereof is that of obtaining the
greatest intensity of chemiluminescent activity per unit weight of
gel that is consistent with the maintenance of suitable gel
characteristics. Thus, although the highest possible concentration
of active ingredients per unit weight of gel would seem to be most
advisable, a high percentage of solid material renders the gel
highly viscous and results in an attendant decrease in the
diffusion-controlled chemiluminescent reaction rate. The result is
a trade-off between brightness and light-emitting lifetime. Our
studies thus far have shown that the optimum activator-to-agent
ratio, considering only the weights of active ingredients, is
approximately 5:1 when ceric ammonium sulphate is the activator.
Since there is no evidence of internal quenching of the
chemiluminescent process by an excess of the oxidizing agent, any
mixture ratio of activator (oxidizer) to luminescent agent will
emit some light and such light will be made available for use
provided it is not absorbed before it can be detected.
In the following tables showing in percentages by weight various
compositions of suitable luminescent agent gels, termed "Agent
Gel," and oxidizing agent gels, termed "Activator Gel," the
luminescent agent used was a silikon in the form of a solid, yellow
mixture which, as previously stated, does not have a definite
composition but which was in this case a mixture of polysiloxenes
(Si.sub.6 H.sub.6 O.sub.3).sub.n, and substituted polysiloxenes,
the latter in possibly various states of oxidation but still
capable of luminescence.
TABLE NO. 1
Agent Gels
No. of Gel % silikon % active silica % water Agent Gel No. 1 7.6
16.4 76.0 Agent Gel No. 2 14.5 13.4 72.1 Agent Gel No. 3 26.3 13.2
60.5
TABLE NO. 2
Activator Gels
No. of Gel % oxidizer* % active silica % water Activator Gel No. 1
14.6 15.2 70.2 Activator Gel No. 2 30.2 20.0 48.8 Activator Gel No.
3 10.8 2.4 86.0** * The oxidizer was ceric ammonium sulfate. This
can be replaced by any of the above listed oxidizing agents ** In
place of water as such, 1M-H.sub.2 SO.sub.4 was used
It should also be understood that in place of the particular
silikon mixture used in the foregoing tables any other silikon
mixture could be used, or any individual chemiluminescent
polysiloxenes or their substitution products as above set
forth.
The following tables show the performance of various mixtures of
Agent and Activator Gels of the compositions given in Tables 1 and
2 in terms of chemiluminescent activity. The headings above the
performance data show the proportions and actual weights of Gel,
Agent and Activator used:
TABLE NO. 3
1 gram agent gel No. 1 (0.263 grams of agent) + 3 grams of
activator gel No. 1 ( 0.437 grams of activator)
RUN 1
Time (seconds) Brightness (ft. lamberts) 10 1.2 35 0.6.sup.2 60
0.1.sup.3 85 0.1.sup.6 125 -- still visible 145 -- but beyond range
of 180 -- instrument
RUN 2
Time (seconds) Brightness (ft. lamberts) 15 1.3 32 0.7.sup.5 60
0.2.sup.5 100 0.1.sup.8 115 0.1.sup.1 still visible 145 -- but
beyond range of instrument
RUN 3
1 gram agent gel No. 1 + 4.4 grams activator gel No. 2
Time (seconds) Brightness (ft. lamberts) 10 1.0 23 0.8.sup.2 38
0.4.sup.3 54 0.1.sup.8 77 0.1.sup.2 111* 0.4.sup.8 128 0.2.sup.3
147 0.1.sup.2 still visible 177 -- but beyond range of instru- ment
* At 111 seconds the gelled system was agitated, whereupon it gave
an additional pulse of emitted light, thereby showing that the
system was capable of further activation
The significant parameter, which characterizes the total available
light energy, is the integral of the brightness over the light
emitting lifetime. This integrated birghtness averages about 58 ft.
lambert seconds over Runs -1, 2 and 3.
ON THE DRAWINGS
Various methods of packaging the luminescent agent and the
oxidizing agent, or activator, are illustrated in the accomapnying
drawings, which are diagrammatic in nature, and in which:
FIG. 1 is an elevational view, partly broken away, of an
encapsulated system;
FIG. 2 is an alevational view, partly broken away, of a modified
encapsulated system;
FIG. 3 is an elevational view, partly borken away, of a gel
dispenser system;
FIG. 4 is a perspective view of a package intended primarily as a
hand signalling device; and
Fig. 5 is an elevational view, partly broken away, of a wave-off
grenade utilizing capsules of the luminescent agent and oxidizing
agnet of our invention.
AS SHOWN ON THE DRAWINGS
In FIG. 1, the reference numeral 10 indicates an outer spherical
container, preferably formed of a transparent plastic film or
membrane 11. Plastics such as polyethylene, ethyl cellulose,
vinylidene chloride and other plastics can be used, or glass can be
employed. The material used should be impermeable to water,
moisture vapor and air, and should be capable of being easily
ruptured by compressive forces exerted thereagainst. While the
thickness of the container wall 11 has been exaggerated for
purposes of illustration, the membrane wall should be relatively
thin, in the neighborhood of 2 to 20 mils, in thickness, although
thicker container walls may be employed so long as they can be
ruptured or broken under the desired conditions of use.
An inner, generally concentric sphere 12, having a wall 13 also
formed of plastic material or glass or other ceramic material, is
positioned within the outer sphere 10. Prior to assembly, said
sphere 12 is filled with a "fuel" 14, viz., a silikon. The silikon
used may be in a dry powdered form or in the form of a water
gel.
An oxidizing agent, indicated by the reference numeral 15, is
positioned in the space between the inner and outer spheres 12 and
10, and, as in the case of the luminescent agent, the oxidizing
agent, or activator, can be in powdered or liquid form, or can be
distributed throughout a water gel.
The proportions of luminescent agent to oxidizing agent, or
activator, are preferably those that will give optimum performance
in use. The concentric method of packaging illustrated by FIG. 1
results in maximum mixing and maximum light output upon rupture of
the walls 11 and 13, or of the wall 13 only, where this can be
accomplished. If only the inner wall 13 is to be ruptured, it
should be of a thin, frangible material, while the outer wall 11
should be stronger, flexible and less easily rupturable so that
forces exerted against the outer wall 11 can be transmitted through
the oxidizing agent 15 to rupture the inner wall 13. Where the
outer container wall 11 is intended to withstand rupturing forces,
it should, of course, be of transparent or transluscent material,
so that the light emitted upon the mixing of the oxidizing agent,
or activator, with the chemiluminescent material 14 can pass
through the unbroken outer wall 11.
In FIG. 2, instead of concentric spheres, there is diagrammatically
illustrated a pair of spherical containers 20 and 21 joined
together in side by side relationship by means of an adhesive,
indicated at 22. Either of the spherical containers 20 or 21 may
contain the luminescent agent, composition 14 and the other contain
the oxidizing agent composition, or activator, 15. As before, the
proportions of the active components of the compositions are such
that upon mixing of the two, satisfactory performance will be
realized. The side-by-side arrangement shown in FIG. 2, while not
resulting in so complete mixing as would give best results, in
nevertheless suitable for applications in which a reactivation of
the chemiluminescent activity is desired.
In FIG. 3, there are illustrated diagrammatically a pair of
pressurized tanks 25 and 26, which may be cylindrical in form and
have walls 27 and 28 of sufficient strength to withstand the gas
pressure, usually from 25 to 100 psi in the spaces 29 and 30 above
the contents 31 and 32, respectively, of said vessels 25 and 26.
Vessel 25, for instance, may contain the chemiluminescent material
14, preferably in the form of a water gel, while vessel 26 contains
the oxidizing agent, or activator 15, also in the form of a water
gel. Delivery tubes 33 and 34, extending in the respective vessels
25 and 26 to points near the bottoms thereof, serve for the
discharge of the contents of these vessels into a common tube 35
provided with a suitable mixing valve 36 and terminating in a
nozzle 37. As shown, the agent and activator gels are discharged in
a single premixed stream from the nozzle 37, but the discharge
could be in unmixed streams, side by side, if that type of valve
were employed.
In the case of the gel dispensers of FIG. 3, the containers would
be filled, or partially filled, with the agent and activator gels
of such concentration as to give satisfactory or optimum
performance, or, if a mixing valve is used, the mixing may be in
such proportions as to give optimum performance. While the gel
dispenser system of FIg. 3 is shown for manual operation, it can,
of course, be provided with a timing device for the timed operation
of a power-actuated valve in place of the valve 36.
In the hand signalling device illustrated in FIG. 4, the reference
numeral 40 indicates an outer container for the chemiluminescent
agent 41, which is suitably in the form of a powder. Within the
outer container 40 is an inner container 42, filled or partially
filled with the oxidizing agent or activator 43 which may be in a
liquid or a flowable pastry state.
In the device of FIG. 4, the shape of the outer container 40 is
such that it may be readily held in the hand for manual operation
in signalling. The material forming the outer container 40 should
be of a transparent, relatively tough material, so that when light
is produced by manually rupturing the inner container 42, as by
squeezing the outer container 40, the light emitted upon mixing of
the contents 41 and 43 can pass through the unruptured outer
container wall.
FIG. 5 illustrates a grenade, indicated generally by the reference
numeral 45, the form and material of which may be similar to the
conventional military hand grenade. Said grenade 45 is in the form
of a closed cylinder 46 and is shown as filled with a large number
of individual capsules 47 and 48 representing, respectively,
capsules of the luminescent agent and of the oxidizing agent, or
activator. As in the case of the conventional grenade, the grenade
45 is provided with a detonator 49 and an igniter 50. Consequently,
when the igniter 50 is properly set for the grenade to explode, the
resulting explosion will effect a mixing of the contents of the
capsules 47 and 48 and the generation of luminescent light.
It will be understood that the capsules 47 and 48 can be formed of
any suitable easily rupturable plastic, or other suitable
encapsulating material, and that the luminescent and oxidizing
agents can be in the form of their water gels, or in the form of
pellets. In the latter case, the pellets can be coated to provide a
continuous inert and impervious film. The size of the capsules 47
and 48 is not critical. The capsules could be one-half inch glass
spheres, but whatever the size, the encapsulating film should have
a relatively weak wall strength so as to be easily ruptured.
Various colors of chemiluminescent light can be produced by
absorbing fluorescent dyes on the surface of the powdered silikon,
such as green, red and yellow colors of light. Yellow-orange is the
basic color of light emitted by silikon.
Primary uses for our chemical light-producing system include the
following:
1. The light-producing materials can be deployed on the boundaries
of land areas to detect the movement of animals at night; for
example, cattle or sheep on a large open range. 2. The
light-producing agent can be used for experimental work requiring
night photographing of movement. 3. Others
The generation of light without heat through time release or
pressure is, in itself, novel to the general public and, therefore,
appears to be of potential interest in the area of tricks, games,
toys, etc.
It will be understood that modifications and variations may be
effected without departing from the scope of the novel concepts of
the present invention.
* * * * *