US 3505236 A
Description (OCR text may contain errors)
United States Patent Ofilice 3,505,236 Patented Apr. 7, 1970 3,505,236 WATER-BASED AEROSOL COMPOSITION Raymond Michael Anstett, Hazlet, N.J., assignor to Colgate-Palmolive Company, New York, N.Y., a corporation of Delaware No Drawing. Filed June 7, 1966, Ser. No. 555,662
Int. Cl. 'C11d 17/08; C09k 3/30 US. Cl. 252-90 5 Claims The present invention relates to water-based aerosol compositions and, more particularly, to water-based aerosol compositions which contain a liquefied normallygaseous propellant, having a density greater than that of the unmodified aqueous phase, and to a method of modifying the density of the aqueous phase to raise its density to a density greater than the density of the propellant phase of the aerosol combination.
When the usual water-based aerosol is emulsified, using a liquefied normally-gaseous propellant having a density greater than that of the aqueous phase, a separation of phases will leave the propellant (propellant phase) on the bottom of the container. As a result, unless the contents of the container is shaken vigorously before use, the propellant only is dispensed.
It has now been found that the problem presented by the combination in water-based aerosols of high density propellants or propellant mixtures with aqueous products, to wit: the separation of a lower propellant phase from an upper product phase, can be overcome by adding to the aqueous phase an organic or inorganic material which in concentrations limited by economics raises the density of the aqueous phase to a density greater than the density of the propellant phase. It is to be noted that the propellant phase can contain a modifier or extender which lowers the density of the propellant phase but which lower density is nevertheless sufficiently greater than the density of the unmodified aqueous phase that the modified propellant phase forms a lower phase when the emulsion breaks.
The material employed to raise the density of the aqueous phase should not only be soluble in the aqueous phase, i.e., in water to the extent necessary to raise the density of the aqueous phase above that of the propellant or modified propellant phase, but also should not be unacceptable for aesthetic reasons. Since the added material is a part of the product sprayed it should not leave spots on the surface sprayed therewith which are objectionable. On the other hand, in some instances such an additive would not be unacceptable because in a subsequent treatment the spots no longer exist as spots but as an invisible film.
The propellant used preferably is a non-flammable propellant as defined by R. J. Scott and his colleagues R. R. Terrill and R. E. Feathers in a series of articles published in Soap and Chemical Specialties, vol. 38, No. 1, page 142 (January 1962), and subsequently entitled Aerosol Propellant Blends I, II and III. In addition, these investigators also disclosed that Propellant A consisting of ten percent of isobutane and ninety percent of a 50/50 mixture of dischloro difluoromethane and trichloromonofluorornethane described by W. H. Reed in the article entitled A New Propellant Blend, Soap and Chemical Specialties, 32 No. 5, 1957 (1956) is non-flammable.
As disclosed in the paper Scott et al. publication, nonfiarnmable propellant blends or mixtures may consist of 15 percent by weight of liquefied dimethyl ether and the balance liquefied dichlorodifluoromethane (Freon 12); and 15 percent by weight liquefied dimethyl ether, percent by weight liquefied trichlorornonofluoromethane (Freon 11) and 75 percent by weight of liquefied dichlorodifluoromethane (Freon 12). In other words, mixtures of the liquid fluoro carbons containing up to 15 percent by weight of liquid dimethyl ether are nonflammable by the criteria established by R. J. Scott and his co-workers.
Having selected the propellant to be used, the inorganic or organic additive for raising the density of the aqueous product phase above that of the propellant phase is selected on the basis of the use for the water-based aerosol and the limiting concentration required by (1) the amount necessary to provide an aqueous phase having a density greater than the density of the unmodified or modified propellant blend or mixture, (2) the solubility limit of the additive in water at ambient temperatures, and (3) whether an additive volatile or non-volatile at environmental conditions is required.
For example, a modifier volatile at environmental conditions in a product for cleaning woodwork, metal surfaces and the like is ammonium bicarbonate (NH HCO On the other hand, polyhydric alcohols such as glycerol, ethylene glycol, propylene glycol can be used in products which are to be used on surfaces which will be wiped or polished after application to the surfaces. Other illustrative additives are ammonium carbamate, ammonium nitrate, ammonium carbonates, the latter being volatile and the other two being non-volatile. Further characteristi-cs of the modifier of the density of the aqueous phase are that the -modifier(s) is not toxic, in the concentration employed, for the ultimate use, is not reactive with the propellant or propellant mixture, is not reactive with the other components of the aqueous phase at temperatures below about 130 F., does not inhibit substantially the formation of an emulsion and is not contra-indicated for the ultimate use by reason of aesthetics, odor or physical reaction. Thus, while ammonium bicarbonate is presently preferred as a modifier of the density of the aqueous phase for a product to be used as a window cleaner, glycerol is presently preferred for a hair spray.
For example, illustrative of a water-based aerosol composition for cleaning woodwork, metal surfaces, and the like is the following formulation providing a non-flammable propellant and an emulsion which separates into a lower aqueous phase and an upper propellant phase.
AQUEOUS PHASE l Water-White clear and free of suspended matter, comprising saturated paratfins, predominantly isoparalfins characterized by:
Acidity of distillation residue Neutral Tagliabue Closed Cup, Flash Point, I min 100 ASTM Distillation, F. min.:
Initial Boiling Point .340 End Boiling Point 410 2 About 15 percent by weight of dimethyl ether, about percent by weight of dichlorodifiuoromethane, and about 10 percent by weight of trichloromonofiuoromethane.
3 A polyglyeerol ester of refined oleic acid. The polyglycerol used in its manufacture contains about 12 to 15 percent; monomeric glycerol, a smaller amount of diglycerol, and the balance consisting of triand higher molecular polyglycerols.
From the foregoing those skilled in the art will understand that the present invention is an improvement in an aerosol package comprising a hermetically sealed container charged, under pressure, with an emulsion comprising two substantially immiscible liquids in emulsified form, said emulsion having an aqueous continuous phase and a liquefied normally gaseous disperse phase, and propellant gas under pressure sufiicient to propel the emulsion from the container. In unmodified form, this emulsion tends to break into an aqueous upper layer and a lower liquefied normally-gaseous or propellant layer.
The liquefied normally-gaseous substance employed in the instant emulsions preferably contains at least one liquefied normally-gaseous low molecular weight halogenated hydrocarbon propellant, such as halogenated ethane, methane and mixtures thereof. The halogenated hydrocarbons known in the art as the Freons and Genetrons and the like have been found to be particularly suitable. Specific examples of such propellants are dichlorodifluoromethane (Freon 12), dichlorotetrafluoroethane (Freon 114), monochlorodifluoromethane (Freon 22), trichloromonofluoromethane (Freon 11) and mixtures thereof. The liquefied propellants generally have a density greater than 1.0 while the aqueous phase has a density of approximately 1.0 and less than the density of the liquefied propellant. Consequently, the present invention provides for adding a water-soluble density modifier to the aqueous phase to raise the density thereof to a maximum dependent upon the solubility of the density modifier in water and to add to the propellant at least one material which is miscible with said liquefied propellant, has a lower density than the liquefied propellant, and preferably volatilizes with the propellant when the emulsion is dispensed to lower the density of the propellant. The most preferred is a propellant modifier which volatilizes with the propellant and also provides with the other components of the propellant a propellant blend which is non-flammable. Illustrative of propellant modifiers are odorless mineral spirits and hexane, pref- 2 erably dual refined hexane. Although the preferred propellant is a mixture of dimethyl ether, dichlorodifiuoromethane and trichloromonofluoromethane which is nonflammable, other propellant blends such as the following can be used in conjunction with an emulsifiable aqueous solution to which an aqueous phase density-modifier, such as enumerated hereinbefore, has been added:
Propellant Blend N 0.
Component, Weight Percent Vinyl chloride Trichloromonofluoromethane D ichlorodifiuoromethane Isobutane 50% Dichlorodifluoromethane 50% Trichloromonofluoromethane.
Total tainer, the step of adding at least one water-soluble, inorganic, ammonium salt selected from the group consisting of nitrate, carbamate, carbonate, and bicarbonate to said aqueous phase in an amount sufiicient to raise the density of said aqueous phase to a density greater than that of said disperse propellant phase whereby said aqueous phase forms the lower phase when the emulsion breaks.
2. The method as set forth in claim 1 wherein additionally a disperse-phase soluble additive selected from the group consisting of odorless mineral spirits and hexane is added to the disperse phase in an amount effective to lower the density of said disperse phase.
3. A pressurized package consisting essentially of a hermetically sealed, valved container; a propellant gas phase; and an oil-in-Water emulsion which consists essentially of an aqueous continuous phase, an oil-in-water emulsifier and a disperse, non-flammable, liquid propellant phase comprising at least 78% by Weight of a liquefied normally-gaseous halogenated, hydrocarbon propellant, said disperse phase having a density greater than 1.0 and the proportion thereof being sufficient to propel the emulsion from the container and said continuous aqueous phase containing at least one water-soluble, inorganic, ammonium salt selected from the group consisting of nitrate, carbamate, carbonate, and bicarbonate in amount effective to raise the density of said continuous phase to a density greater than that of said disperse phase.
4. The package as set forth in claim 1 wherein said inorganic salt is ammonium bicarbonate.
5. The package as set forth in claim 1 wherein said disperse phase contains in addition a disperse-phase soluble additive selected from the group consisting of odorless mineral spirits and hexane in amount effective to lower the density of said disperse phase.
References Cited UNITED STATES PATENTS 2,964,165 12/1960 Riley 252305 2,968,628 1/1961 Reed 252-305 2,995,278 8/1961 Clapp 252305 FOREIGN PATENTS 748,411 5/1956 Great Britain. 858,5 44 l/ 1961 Great Britain.
LEON D. ROSDOL, Primary Examiner W. SCHULZ, Assistant Examiner Us. 01. X.R. 252 92, 30s