US 3650956 A
Description (OCR text may contain errors)
3,650,956 HEAVY-DUTY AEROSOL CLEANER David L. Strand, Maplewood, and Roger L. Abler, White Bear Lake, Minn., assignors to Minnesota Mining and Manufacturing Company, St. Paul, Minn. No Drawing. Filed May 28, 1969, Ser. No. 828,701 Int. Cl. (111d 17/00 US. Cl. 252-90 5 Claims ABSTRACT OF THE DISCLOSURE A heavy-duty foaming aerosol abrasive cleaner composition particularly adapted for cleaning hard surface floors without detrimental effect on floors or fioor finishes. The cleaner comprises a thixotropic suspension of bentonite, abrasive particles, reducing agent for corrosion prevention, an effective amount of at least one higher fatty acid alkanolamide to provide a visible foam, and sufficient water to provide the desired viscosity.
BACKGROUND OF THE INVENTION This invention relates to heavy-duty foaming aerosol abrasive cleaner compositions particularly adapted for use with rotary floor cleaning machines to clean hard surface floors.
The floor cleaning art has desired cleaner compositions to quickly and uniformly clean a floor down to the base polish coat, without the use of copious amounts of water, without removing the floor from service and with a minimum amount of labor. Soil such as black marks and imbedded dirt has typically been removed by applying copious amounts of aqueous detergent or soap solutions and scrubbing the floor with low-density abrasive cleaning pads, steel wool pads, or bristle brushes driven by conventional floor cleaning and polishing machines. The detergent or soap solution is then removed, disposed of, and the floor surface rinsed with water. This traditional method is slow, cumbersome, laborious, expensive, removes the floor from safe service and often removes the base polish coat, necessitating subsequent reapplication. Additionally, aqueous solutions darken, swell, and rot wood floors. Further, the floor cleaning machine often throws detergent and soil on walls and furniture necessitating expenditure of extra labor for cleanup.
Liquid detergent compositions and abrasive cleaner com-positions dispensable by means of plastic squeeze bottle or aerosol spray are known in the art, typical compositions being shown in US. Pats. 2,920,045; 3,149,078; 3,210,285; and 3,210,286; and the R. T. Vanderbilt Company Trade Bulletin No. 44 (1964) on page 27. Cleaner compositions of this type have been found unsatisfactory for use with floor cleaning machines as a replacement for traditional floor cleaning methods. These compositions either provide a thick paste or a stiff, thick, slowdraining, persistent foam similar to shaving cream or whipped cream. A stiff, thick paste or foam neither wets the floor surface nor flows under the floor pad, but is pushed along the floor surface or thrown to the side onto walls, furniture, etc. Other difficulties encountered with prior art aerosol abrasive cleaners include settling and separation of the composition Within the container and plugging of the spray nozzle orifice.
Thus, despite the desirability of a cleaner to replace the slow, cumbersome, laborious, expensive, unsafe use of aqueous detergent and soap solutions, a truly satisfactory product has never heretofore existed.
nited States Patent C 3,650,056 Patented Mar. 21, 1972 SUMMARY This invention provides a cleaner composition having excellent soil removing properties. The cleaner effectively replaces the slow, cumbersome, laborious, expensive, unsafe use of aqueous detergent and soap solutions. The composition provides an aerosol-dispensable foam which is readily visible on the floor and will persist for several minutes, but which breaks to a liquid when subjected to mechanical agitation such as that applied by a floor cleaning machine. The foaming composition is aerosoldispensable without plugging of the spray nozzle orifice and without settling or separation of the composition. The foam cleaner, while particularly adapted for use on floors with rotary cleaning machines, can also be used to clean such articles as vinyl upholstery, sinks, dishes, pots, and pans.
In accordance with the invention, the heavy-duty abrasive cleaner composition comprises a homogeneous dispersion of bentonite, water-insoluble abrasive particles having a particle size below 325 mesh, an effective amount of compatible reducing agent to prevent container corrosion, an effective amount of at least one higher fatty acid alkanolamide, and sufiicient water to provide an apparent Brookfield solution viscosity of about 200 to about 800 centipoises when measured with a No. 2 spindle at 6 r.p.m. If desired, minor amounts of other components may be included for specific formulation purposes such as antibacterial aids and odorants.
It has been found that the cleaner composition of this invention, having an apparent solution viscosity of about 200 to about 800 centipoises, is readily dispensable from a conventional aerosol container to provide a desired foam which is readily visible for several minutes when sprayed on a floor surface, but which will break to a liquid when subjected to mechanical shear force. A 1- second spray of this cleaner composition from a distance of about 12 inches provides a thin foam generally less than about inch thick which persists for about 2 to about 5 minutes. This length of time permits the floor machine operator to see where he has applied cleaner, the foam breaking to a liquid when contacted by the floor machine. The ability of the foam to break to a liquid when subjected to shear force is readily demonstrated by applying a l-second spray to the palm of ones hand and thereafter rubbing the hands together several times. The foam quickly breaks to a liquid, in sharp contrast to a shaving cream foam which persists for long periods of time, even under shear force.
The aerosol package used with the heavy-duty abrasive cleaner compositions of this invention generally comprises a pressure-tight container having a typical aerosol dispensing valve which controls flow through a discharge conduit leading from the base of the container. A preferred container utilizes a dispensing valve having a vapor phase hole therein. This valve also permits the cleaner composition to be dispensed when the container is in either an upright or inverted position. The propellant utilized with aerosol cleaner compositions must not react with the cleaner components to render them ineffective or cause the propellant to hydrolyze or otherwise decompose and lose its effectiveness. The propellant, which is employed in the amount of from about 5 to about 20% by weight of the contents of the container, preferably from about 6 to about 12%, is propane, butane, isobutane, or mixtures thereof, with isobutane being preferred because of its ideal vapor pressure at ambient temperatures.
Bentonite is a substantially water-insoluble clay which displays strong colloidal properties and increases its volume several fold by swelling, when in contact with water,
giving rise to a thixotropic, gelatinous suspension capable of holding substantial amounts of abrasive particles in suspension. The solution viscosity obtained is dependent on the particular bentonite utilized and the amount of shear force used in preparing the suspension. It has been found that Wyoming bentonite which has a particle size of 4 microns or smaller, with particles smaller than 2 microns predominating, and containing at least 85% montmorillonite, provides particularly satisfactory foams. Montmorillonite, is a high aluminum content silicate having a plate like crystal structure. Since the solution viscosity of each lot of bentonite will vary slightly, it has been found best to use an amount of bentonite and a degree of shear mixing which provides a Brookfield viscosity of about 400 to about 600 centipoises when 100 parts by weight of bentonite is mixed with 2000 parts by weight of water and measured at r.p.m. with a No. 2 spindle.
The abrasive particles, which substantially increase the heavy-duty cleaning properties of the composition, may be selected from a large group of well known materials in H cluding synthetic alumina, emery, corundum, silicon carbide, volcanic ash, iron oxide, diatomaceous earth, boron carbide, pumice, feldspar, and mixtures thereof; however, it is preferred to employ silica as the abrasive in the present compositions because of its highly eifective cleaning action. The particle size of the abrasive must be such that the abrasive will readily remain suspended in the composition and pass through the nozzle orifice of an aerosol container. Abrasive particles of a size such that they pass through a 325 mesh U.S. Standard sieve may be utilized. It has been found that an effective amount of abrasive particles which readily remain suspended in 100 parts of bentonite ranges from about 100 to about 500 parts by weight, preferably about 200 parts. Use of less than about 100 parts by weight of abrasive per 100 parts of bentonite does not provide effective abrading and cleaning action, while use of more than about 500 parts provides a suspension which has an excessively high viscosity and cannot be readily dispensed from aerosol containers, is subject to settling and separation, or both.
About 650 to 750 parts of water blended with 100 parts of bentonite-abrasive mixture provides a suspension viscosity of about 400 cps. when tested with a Brookfield No. 2 spindle at 6 r.p.m. This amount of water is about 1500 to about 3000 parts by weight per 100 parts of bentonite. Use of less Water provides an excessively viscous dispersion which is not readily dispensable from the aerosol container, while use of more water provides a low viscosity dispersion which is not stable and settles or separates. The amount of water necessary to provide the desired viscosity will vary somewhat with each particular lot of bentonite used. In preparing the composition, the water is mixed with the bentonite using shear agitation, to provide a stable thixotropic suspension and the abrasive thereafter blended in.
If desired a portion of the water in the suspension can be replaced with other liquid components. For example, the inclusion of up to about 150 parts by weight per 100 parts of bentonite, of lower aliphatic alcohols such as methanol, ethanol, propanol, isopropanol, etc., isopropanol being preferred, aids in increasing the cleaning eifectiveness of the composition. It is also thought that the alcohol causes the aerosol propellant to become somewhat soluble in the composition, thereby providing a more homogeneous foam. Greater amounts of alcohol may be added if desired but have not been found to be of beneficial value.
The heavy-duty aerosol cleaner composition of this invention essentially contains an effective amount of at least one compatible corrosion preventing agent. It has been found that aerosol container linings are not sufficiently continuous to prevent aqueous solutions from penetrating the coating and attacking the can metal. Compatible reducing agents such as sodium nitrite, sodium benzoate, sodium borate, phosphate esters, morpholine, and water soluble organic amines have been found particularly effective. Compatible reducing agents are those which either dissolve or disperse in the composition to provide a homogeneous dispersion. Amounts of reducing agent effective to prevent corrosion have been found to range from less than about 1 part to about 25 parts by weight per 100 parts of bentonite, about 1 to about 15 being preferred.
The aerosol cleaner composition of this invention also essentially contains an effective amount of at least one higher fatty acid alkanolamide, such as the monoethanol amides, diethanol amides, or isopropanol amides wherein the acyl radical has about 10 to about 18 carbon atoms. Examples of such amides are lauric, capric, caprylic, palmitic, stean'c, oleic, linoleic, and myristic diethanol amide, monoethanol amide, and isopropanol amide. These alkanol amides provide a readily visible foam such that a floor cleaning machine operator can see where he has dispensed cleaner, the foam being clear and not visible without alkanolamide. Further, these alkanolamides cause the foam to wet the floor surface, persist for only a few minutes, and break easily. An effective amount of alkanolamide to provide a readily visible foam has been found to be about 5 to about 100 parts by weight per 100 parts of bentonite, about 10 to about 60 parts being preferred. Using less than about 3 parts by weight per 100 parts of bentonite does not provide a sufficiently visible foam, while more than about 100 parts provides an excessively stiff and therefore undesirable foam. Further, use of excessive alkanolamide leaves a residue on the floor surface.
If desired, ammonium hydroxide may be included in the composition to provide numerous beneficial properties. For example, it functions as a preservative by providing a pH greater than 9, a corrosion inhibitor, a viscosity stabilizer, and an aid in cleaning the floor surface. The ammonium hydroxide, being fugitive and volatile, evaporates rapidly from the floor surface and does harm the floor coating nor increase its water sensitivity by virtue of residual caustic. Effective amounts of concentrated (28%) ammonium hydroxide have been found to range up to about 250 parts by weight per 100 parts of bentonite, 30 parts being preferred. Minor amounts of other components such as odorants and coloring agents may be added if desired.
The following examples, in which all parts are by weight unless otherwise noted, illustrate preparation of the heavy-duty aerosol abrasive cleaner composition of this invention, without limiting the scope thereof.
DESCRIPTION OF PREFERRED EMBODIMENTS Example I Forty gms. of bentonite having a 90% montmorillonite content, a specific gravity of 2.7, an index of refraction of 1.55, and a particle size such that 96% passes through a 200 mesh U.S. Standard sieve (available from the American Colloid Company) was blended into 823.9 gms. of water and mixed with shear agitation by means of an air driven laboratory propeller mixer until a viscosity of 500 cps. was obtained. This took about one hour. Then gms. of grade 360 and finer ground silica (Nicrosil, Ottowa Silica Co.), 21.3 gms. isopropyl alcohol, 21.3 gms. concentrated (28%) ammonium hydroxide, and 8.5 gms. of a coconut fatty acid diethanol amide (Hyonic LA- 45, Nopco Chemical Company) were blended into the mixture to provide a thixotropic suspension having a pH of about 10.7. The Brookfield viscosity was 800 cps., when tested using a No. 2 spindle at 6 r.p.m.
Six hundred grams of the suspension was filtered through a 60 mesh screen and packaged in a 24-ounce lined aerosol can together with 60 grams of isobutane propellant. A valve having a 0.025 inch metering orifice and a 0.020 inch vapor phase hole (Aerosol Research KN38 valve) was crimped onto the container. The spray tip had a.
0.025 inch diameter orifice (Aerosol Research Company, RKN-105) and the delivery rate of the product was found to be 1.9 gms. per second.
The effectiveness of this cleaner composition was evaluated by installing a low-density fibrous abrasive floor cleaning pad (Scotch-'Brite Brand Blue Cleaner Pad, Minnesota Mining and Manufacturing Company) on a 17-inch commercial rotary floor machine and cleaning a vinyl asbestos tile floor coated with a self-polishing acrylic floor polish (Step Ahead," S. C. Johnson Co.) and heavily soiled with black shoe and crayon marks, and embedded dirt. This floor area was sprayed with the aerosol cleaner composition to provide a low but readily visible foam on the floor surface and the floor cleaning machine with the low-density abrasive pad attached thereto was passed over the foam 6 times. It was found that the embedded dirt, shoe marks, and crayon marks were removed from the floor surface, there was no deposit of residue on the floor surface that could not be removed by dry mopping, and the water sensitivity of the remaining floor coating was not increased.
A control test was performed by flooding a similarly soiled floor surface with water containing a commercial floor cleaning detergent, and scrubbing the floor with the same low-density abrasive floor pad and floor polishing machine. After 6 passes over the soiled floor area, removal of the detergent solution, and rinsing, the floor surface, while clean, was essentially void of polish. The control test was found to take about 3 times as long to clean the same area floor.
Example II Another cleaner composition containing a greater amount of abrasive was prepared using the same components and the same procedure utilized in Example I. The formulation was as follows:
This composition was packaged and tested as described in Example I and was found to effectively remove imbedded soil from hard surface floors. This composition was also used to clean a badly stained brush-finish stainless steel sink. All stains were readily removed with a minimum amount of scrubbing with a low-density abrasive pad.
What we claim is:
1. An aerosol-dispensible foam cleaner composition consisting essentially of about 100 parts by weight of bentonite clay, about 100 to about 500 parts by weight of water-insoluble abrasive particles having a particle size such that they pass through a 325 mesh sieve, 100 parts by weight of at least one higher fatty acid alkanolamide to provide a visible foam, said alkanolamide selected from the group consisting of monoethanol amides, diethanol amides, or isopropanol amides wherein the acyl radical has about 10 to about 18 carbon atoms, about 1 to about 25 parts by weight of corrosion inhibitor, up to about 150 parts of at least one lower aliphatic alcohol, about 10 to about 250 parts of concentrated ammonium hydroxide, and about 1500 to about 3000 parts by weight of water, said composition having an apparent Brookfield solution viscosity of about 200 to about 800 centipoises when measured on a No. 2 spindle at 6 r.p.m.
2. The composition of claim 1 wherein the alcohol is isopropanol.
3. The composition of claim 1 wherein the alkanol amide is a coconut fatty acid diethanol amide.
4. An aerosol-dispensable foam cleaner composition consisting essentially of about 100 parts by weight of bentonite clay containing at least high aluminum content montmorillonite, about to about 500 parts by weight of water-insoluble silica abrasive particles having a particle size such that they pass through a 325 mesh sieve, about 1 to about 25 parts by weight of corrosion inhibitor, about 5 to about 100 parts by weight of a coconut fatty acid diethanol amide, about 10 to about 250 parts by weight of concentrated ammonium hydroxide, up to about 150 parts of at least one lower aliphatic alcohol and about 1500 to about 3000 parts by weight of water, said composition having an apparent Brookfield solution viscosity of about 200 to about 800 centipoises, when measured with a No. 2 spindle at 6 r.p.m.
5. An aerosol-dispensable foam cleaner composition consisting essentially of about 100 parts by weight of bentonite clay containing at least 85% high aluminum content montmorillonite, about 100 to about 500 parts by weight of silica particles having a particle size such that they pass through a 325 mesh sieve, about 1 to about 25 parts of sodium nitrite, about 1 to about 150 parts by weight of isopropanol, about 10 to about 250 parts by weight of concentrated ammonium hydroxide, about 5 to about 100 parts by weight of at least one coconut fatty acid diethanol amide, and about 1500 to about 3000 parts by weight of water, said composition having an apparent Brookfield solution viscosity of about 200 to about 800 centipoises when measured with a No. 2 spindle at 6 r.p.m.
References Cited UNITED STATES PATENTS 2,489,848 11/1949 Bacon et a1. 252 2,524,380 10/1950 Flaxman 252139 2,920,045 1/ 1960 Hearn et a1. 252-137 3,149,078 9/1964 Zmoda 252-137 3,210,285 10/1965 Gangwisch 252-137 3,210,286 10/1965 Gangwisch 252137 LEON D. ROSDOL, Primary Examiner W. E. SCHULZ, Assistant Examiner US. Cl. X.R.
UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Inventor) David L. Strand and Roger L. Abler It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
Column A, line 37, and does harm" should be "and does not harm" Signed and sealed this 11 th day of July 1972.
EDWARD M.FLETCI IER, JR. ROBERT GOTTSCHALK A-ttesting Officer Commissioner of Patents FORM Po-1050 (10-69) USCOMM'DC 50376-P69 9 05. GOVERNMENT PRINTING OFFICE i969 0-386-334