U.S. patent number 3,694,546 [Application Number 04/310,470] was granted by the patent office on 1972-09-26 for two-phase aerosol spraying system.
This patent grant is currently assigned to J. R. Geigy A. G.. Invention is credited to Willi Roth, Otto Erwin Schenk.
United States Patent |
3,694,546 |
Roth , et al. |
September 26, 1972 |
**Please see images for:
( Certificate of Correction ) ** |
TWO-PHASE AEROSOL SPRAYING SYSTEM
Abstract
The invention concerns a two-phase system, comprising an aerosol
pressure container which contains a sprayable mixture therein,
consisting essentially of a liquid phase of active ingredients; a
propellant, liquefiable under pressure which may be either carbon
dioxide and/or nitrous oxide and a liquid dimethoxymethane as an
effective propellant dissolving agent for the carbon dioxide -
nitrous oxide propellants.
Inventors: |
Roth; Willi (Strengelbach,
Kanton Aarau, KA), Schenk; Otto Erwin (Basel,
CH) |
Assignee: |
J. R. Geigy A. G. (Basel,
CH)
|
Family
ID: |
23202661 |
Appl.
No.: |
04/310,470 |
Filed: |
September 20, 1963 |
Current U.S.
Class: |
424/45;
504/363 |
Current CPC
Class: |
A61Q
19/00 (20130101); C09K 3/30 (20130101); A61K
8/046 (20130101); A61Q 17/02 (20130101) |
Current International
Class: |
A61K
8/04 (20060101); C09K 3/30 (20060101); A61k
009/10 () |
Field of
Search: |
;424/45 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Goldberg; Jerome D.
Assistant Examiner: Turner; Vincent D.
Claims
What we claim is:
1. In a two-phase aerosol spraying system comprising an aerosol
pressure container and a sprayable mixture contained in said vessel
under pressure, which mixture consists essentially of a non-aqueous
liquid phase to be sprayed containing an effective amount of the
active ingredients, said ingredients being non-reactive with carbon
dioxide or nitrous oxide, a propellant dissolved therein and
gasified under normal pressure, and the gaseous phase of the
propellant, the improvement wherein said mixture contains 25 to 95
percent by weight of dimethoxymethane calculated on the total
weight of the mixture and 5 to 15 percent by weight of a member
selected from the group consisting of carbon dioxide and nitrous
oxide.
2. In a two-phase aerosol spraying system comprising an aerosol
pressure container and a sprayable mixture contained in said vessel
under pressure, which mixture consists essentially of a non-aqueous
liquid phase to be sprayed containing an effective amount of the
active ingredients, said ingredients being non-reactive with carbon
dioxide or nitrous oxide, a propellant dissolved therein and
gasified under normal pressure, and the gaseous phase of the
propellant, the improvement wherein said mixture contains 60 to 75
percent by weight of dimethoxymethane calculated on the total
weight of the mixture and 8 to 10 percent by weight of a member
selected from the group consisting of carbon dioxide and nitrous
oxide.
Description
The present invention relates to improved two-phase aerosol
spraying systems consisting of a pressure vessel and a mixture
which can be sprayed under pressure contained therein, this mixture
consisting of a liquid phase to be sprayed containing active
ingredient and carbon dioxide and / or nitrous oxide partly
dissolved therein and partly in gas form, as propellant.
Up to the present, the use of carbon dioxide (CO.sub.2) and nitrous
oxide (N.sub.2 O) as propellants in the aerosol industry has been
limited mainly to pressure packings from which it is simple to
remove the contents in the form of foam, paste or liquid; the
principal contents of these pressure packings have been foodstuffs
such as, e.g. cream, cosmetic preparations such as, e.g.
toothpaste, or pharmaceuticals such as, e.g. syrups. Because of the
relatively bad solubility of these gases in the mainly aqueous
products to be taken from these packings, the modest gas reserve
which is formed under pressure is sufficient in the above cases to
empty the packings completely. However, if it is desired to bring
the product to be removed into a more or less finely distributed
form, i.e. to attain a spray mist, then the proportion of
propellant in the product to be sprayed must be considerably
increased and the propellant must be excellently soluble therein.
While, normally, it is quite possible to incorporate a sufficiently
high proportion of propellant in the contents of the packing to
attain a fine spray thereof with the aid of propellants which
liquefy under pressure such as, e.g. dichlorodifluoromethane,
dichlorotetrafluoroethane, vinyl chloride, propane, butane, etc.,
the greatest difficulties are encountered with carbon dioxide and
nitrous oxide because of their slight solubility in the phase to be
sprayed. In particular, these difficulties occur with aqueous
products because the solubility of carbon dioxide and nitrous oxide
in aqueous media is very slight. When using spray button, such
mixtures can usually be sprayed well initially, but the gas
pressure drops so strongly as the aerosol is emptied, that the
spray pattern changes to an undesirable extent, while the apparatus
is in use, the fog becoming more and more coarsely dispersed and
the amount of material leaving the valve becoming smaller with
time. In addition, on using carbon dioxide and nitrous oxide, the
small gas reserve present in the known mixtures has a
disadvantageous effect as such aerosol packings lose their pressure
to a great extent even with the slightest leak and faulty
manipulations and become quickly unusable.
In view of their attractive price and also because of their slight
toxicity and high stability, there has been no lack of attempts to
find ways of using these gases (CO.sub.2 and N.sub.2 O) for the
fine spraying of products in spite of the difficulties mentioned
above. In particular, attempts have been made to find substances
having particularly good solubility powers for carbon dioxide and
nitrous oxide from among the organic solvents. The solvents which
have been suggested up to now are mainly alcohols, ketones, esters
and chlorinated hydrocarbons such as, e.g. ethanol, isopropanol,
acetone, methyl acetate, ethyl acetate, methylene chloride etc. For
use in the most finely sprayable aerosols, these solvents either
have too slight a solubility for carbon dioxide and nitrous oxide,
a too pronounced odor, too high a toxicity, they attack the
elastomers of the aerosol packing excessively or they have
insufficient chemical stability in the presence of water.
It has now surprisingly been found that dimethoxy-methane has a
previously unknown, remarkably good solubility for gaseous
CO.sub.2, N.sub.2 O, and mixtures thereof in a random ratio of
CO.sub.2 : NO.sub.2, and, as solvent for these gases, is superior
in every way to the organic solvents mentioned above in its
suitability for formulation in aerosols as can be seen from the
following Table:
solvent lowest proportion- toxic pract- behavior towards ality
thresh- ical elastomers constant.sup.1 hold concen- (weight take-up
value tration in %) .sup.k CO.sub.2 .sup.k N.sub.2 O (ml.sup./
m.sup.3) in air (g/m.sup.3).sup.(2) "Buna N" "Neoprene"
__________________________________________________________________________
dimethoxy- methane 1.45 1.20 1000 119 21.5 11.8 isopro- panol 0.44
0.51 400 67 0.0 0.0 methylene chloride.sup.3 0.56 0.62 500 -- 122.0
161.0 dioxan 1.02 0.73 100 79 67.0 64.0 ethyl acetate.sup. 3 1.00
1.01 400 79 31.0 39.0 methyl acetate.sup. 3 1.21 1.04 200 103 41.0
45.5 acetone 1.26 1.15 500 56 41.0 48.0 diethyl ether 1.26 1.11 400
59 -- --
__________________________________________________________________________
From the Table it is clearly seen that, on the whole,
dimethoxy-methane combines most of the positive properties required
of a solvent for propellants namely:
1. superior solubility powers for the propellant gases
expressed by the proportionality constant k in Henry's law, c = k.
p. in which c is the concentration of the dissolved gases (in
percent by weight) and p is the equilibrium pressure (in
kg/cm.sup.2);
2. slight toxicity
expressed as the toxic threshold value in milliliter of solvent, in
vapor form, per cubic meter of air.
3. small danger of explosion
expressed as the lowest practical concentration in the air in grams
of solvent per cubic meter of air, and
4. slight attack on the elastomers used as aerosol container
material
expressed in the percentual take-up of solvent by the elastomers on
storing in the solvent tested for 7 days.
It has further been found that, unexpectedly, a much quicker, finer
distribution of the spray particles is obtained which is probably
due to a much quicker release of the propellant dissolved with the
aid of dimethoxymethane, directly after the spray has left the
valve, than when using another propellant-dissolving agent, for
instance isopropanol or dioxane. As a further advantage
dimethoxymethane has an ignition point of 470.degree. C. which
distinguishes it especially from diethyl ether whose ignition point
of 180.degree. C. makes it too dangerous for using. It could be
determined from the tests that dimethoxymethane saturated with
carbon dioxide or nitrous oxide at equilibrium pressures of over 2
atmospheres excess pressure attains an aerosol effect which is at
least equal in practice to that of the conventional pressure
liquefied propellant gases such as Freon.
In principle, the phase to be sprayed in the apparatus according to
the invention, can contain in addition to the active substances
only dimethoxymethane with carbon dioxide or nitrous oxide
dissolved under pressure, or it may further contain other organic
solvents in combination with dimethoxymethane.
The sprayable phase in the apparatus according to the invention can
contain active ingredients of any type such as, e.g. pest control
agents, weed killers, pharmaceuticals, cosmetics, household
chemicals etc. in dissolved or dispersed form except, of course,
active ingredients which react with carbon dioxide or nitrous
oxide, in an amount of 0.01 to 50 percent preferably 0.05 to 20
percent by weight.
The following examples illustrate a few preferred forms of the
mixture according to the invention. Where not otherwise stated,
parts are given as parts by weight. The relationship of parts by
weight to parts by volume is as that of grams to cubic
centimeters.
EXAMPLE 1
2-isopropyl-4-methyl-6-pyrimidyl-0,0 -diethyl-thiophosphate 3.75
parts hexachlorocyclohexane 1.00 part dimethoxymethane 222.50 parts
carbon dioxide 22.50 parts epichlorohydrin 0.25 part
2-Isopropyl-4-methyl-6-pyrimidyl-0,0-diethyl thiophosphate,
hexachlorocyclohexane and epichlorohydrin as stabilizer for the
thiophosphate are dissolved in dimethoxymethane. 227.5 Parts of
this mixture are put into an aerosol container of 350 parts by
volume capacity and then the valve is fixed. 22.5 Parts of carbon
dioxide are introduced through the valve while shaking, which
amount of gas corresponds to about 33 times the total volume of the
container under normal conditions. The mixture formed, (at an
initial inner pressure of about 5.5 atmospheres excess
pressure/20.degree. C. and an end pressure of about 4.0 atmospheres
excess pressure/20.degree. C.) can be perfectly and completely
sprayed as a dry mist and is excellently suitable for the
combatting of flying insects.
EXAMPLE 2
propylene glycol 0.75 part triethylene glycol 0.75 part methylene
chloride 27.75 parts dimethoxymethane 108.00 parts nitrous oxide
12.00 parts.
The liquid components of the mixture are dissolved in each other.
138 Parts of this mixture are then put into an aerosol container of
220 parts by volume capacity and the valve is fixed. 12 Parts of
nitrous oxide are introduced through the valve while shaking, which
amount of gas corresponds to 28 times the total volume of the
container under normal conditions. The mixture formed can be
perfectly and completely sprayed as a dry mist (at an initial
pressure of about 6.4 atmospheres excess pressure/20.degree. C and
an end pressure of about 4.3 atmospheres excess pressure/20.degree.
C). It can be used as a room deodorant.
EXAMPLE 3
highly dispersed silicic acid 2.5 parts 1,1,1-trichloroethane 10.0
parts acetone 10.0 parts xylene 10.0 parts dimethoxymethane 61.5
parts carbon dioxide 6.0 parts
The silicic acid is pasted in the liquid components. 94 Parts of
the mixture are put into an aerosol container of 220 parts by
volume capacity and 6 parts of carbon dioxide are introduced
through the valve while shaking. The amount of gas corresponds to
about 14 times the total volume of the container under normal
conditions. The mixture formed can be perfectly and completely
sprayed (at an initial inner pressure of about 3.8 atmospheres
excess pressure/20.degree. C and an end pressure of about 2.5
atmospheres excess pressure/20.degree. C) and can be used to remove
stains on textiles.
EXAMPLE 4
o-chlorobenzoyl diethylamine 9.0 parts benzoyl diethylamine 9.0
parts isopropanol 12.0 parts dimethoxymethane 111.0 parts nitrous
oxide 9.0 parts
o-Chlorobenzoyl diethylamine and benzoyl diethylamine are dissolved
in the isopropanol and dimethoxymethane. 141 Parts of this mixture
are then put into an aerosol container of 220 parts by volume
capacity and the valve is fixed. 9 Parts of nitrous oxide are
introduced through the valve while shaking, which amount of gas
corresponds to about 21 times the total volume of the container
under normal conditions. The mixture formed can be perfectly and
completely sprayed (at an initial inner pressure of about 5.0
atmospheres excess pressure/20.degree. C and an end pressure of
about 3.1 atmospheres excess pressure/20.degree. C) and is
excellently suitable as a repellant for mosquitoes.
EXAMPLE 5
dichloroxyquinaldine 2.0 parts isopropyl myristate 10.0 parts
isopropanol 28.0 parts dimethoxymethane 146.0 parts carbon dioxide
14.0 parts
Dichloroxyquinaldine is dissolved in isopropyl myristate, ethanol
and dimethoxymethane. 186 Parts of this mixture are put into an
aerosol container of 350 parts by volume capacity and then the
valve is fixed. 14 Parts of carbon dioxide are introduced through
the valve while shaking, which amount of gas corresponds to about
20 times the total volume of the container under normal conditions.
The mixture formed can be perfectly and completely sprayed (at an
initial inner pressure of about 4.9 atmospheres excess
pressure/20.degree. C. and an end pressure of about 3.4 atmospheres
excess pressure/20.degree. C.) and is excellently suitable for the
disinfection of external wounds as well as for combatting foot
mycosis.
EXAMPLE 6
carnauba wax 4.0 parts beeswax, bleached 6.0 parts paraffin
50/52.degree.C 8.0 parts terpentine oil 41.0 parts silicone oil
(500 centistokes) 1.0 part dimethoxymethane 130.0 parts carbon
dioxide 10.0 parts
Carnauba wax, beeswax and paraffin are heated with the terpentine
oil to 110.degree. C. until solution occurs; the solution is then
quickly cooled to 20.degree. C. while stirring and the paste formed
is homogeneously mixed with dimethoxymethane. 190 Parts of this
mixture are put into an aerosol container of 350 parts by volume
capacity and the valve is fixed. 10 Parts of carbon dioxide are
introduced through the valve while shaking, which amount of gas
corresponds to about 15 times the total volume of the container
under normal conditions. The mixture formed can be perfectly and
completely sprayed (at an initial inner pressure of about 3.9
atmospheres excess pressure /20.degree. C. and an end pressure of
about 2.6 atmospheres excess pressure/20.degree. C.) and is
excellently suitable as a floor polish.
EXAMPLE 7
o-chlorobenzoyl diethylamine 9.0 parts benzoyl diethylamine 9.0
parts isopropanol 12.0 parts dimethoxymethane 111.0 parts nitrous
oxide 5.0 parts carbon dioxide 4.0 parts
o-Chlorobenzoyl diethylamine and benzoyl diethylamine are dissolved
in the isopropanol and dimethoxymethane. 141 Parts of this mixture
are then put into an aerosol container of 220 parts by volume
capacity and the valve is fixed. 9 Parts of a mixture consisting of
5.0 parts of nitrous oxide and 4.0 parts of carbon dioxide are
introduced through the valve while shaking, which amount of gas
corresponds to about 21 times the total volume of the container
under normal conditions. The mixture formed can be perfectly and
completely sprayed (at an initial inner pressure of about 5.0
atmospheres excess pressure/20.degree. C. and an end pressure of
about 3.1 atmospheres excess pressure/20.degree. C.) and is
excellently suitable as a repellant for mosquitoes.
* * * * *