Note: Descriptions are shown in the official language in which they were submitted.
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Removing Stubborn Mildew Stain
BA~~~'~ti3l~ !~~'~IPd~Ehi''I~IOI~
Field o~the hrventi~an
This invention relates to a cleanirdg composition for removing stubborn mildew
aiad otliLr
zU mycological stains frown surfaces, the cleaning comqansitior~ comprising
are aqueous solution ofan
alkali metal hypochlorite, an alkaline br~alder, and a hypochtorite-
~carr~patihle sunf'act~aaat. Mare
particuiaxly, the invention concerns such a cleaning composition ewhicl~ is
fluid foam having a
particular combination of characteristics and a process for preparing the
cleaning co~npositios~
~uici Edam.
IS ~escr_iption o~the lPrior ~.rt
Various aqueous rn3ldew-rerr~OVix~g products are available commercially for
home use.
Typically, the aqueous products coutaiav a metal hypochlorite, an alkaline
builder far maintaining
the aqueous product at a pI~ o~ at least 11, and a surfactant. Such products
typilly are dispensed
i'rcarn plastic bottles equipped with hand-activated pumps for sprayiaag ithe
cleaner on a surFace.
~0 The sprayed cleaning compositions usually are dispensed as liquids, short-
liv$d foanns, thiclreued
liquids or gels.
Several aqueous alkali rttetal hypachlarite compositions far tine rerrtn~val
of mildew stains,
similar to those in the commercial products, are disclosed in patents, such as
hluited States
Patents, 5,281,287 (Lisor~rski et aid, 5,29C~,47fl (butcher et al), a~xd
S,~b'1,2~~ ~Hawes). "I~a
25 presern inventor found that although soave of the lct3.~twn cleaning
eaaxipositions remove mildew
stains o~ mild intensity, none o~tl~e tested. com!~ercial ~aratlucts could
reara~:ve long established,
stubb~arn mildew stains ia~nless cleaning was accompaniedl by vigor~aa~s
scrcnbbing. 1n addition,
almost all oftl~e tested products lost cleaning efficiency wig. aging during
storage.
'Il~e use o~ tlticlcening agents to inGre~se viscosity and change flout
characteristics of
34 aqueous hygochlorite-containing cleaning campositiorts in orster to i~npxo
a their cleaning ability
is disclosed in various patents, as for exxamlale in l~nited States iPatenta
5,549,84 (I~lzang~,
~,q00,467 (Smith), x,8(10,036 (Rose et alj, arid 4,337,163 (Schilp).
'~'hethickened litluids ~xsuady
are disclosed fear tale as detergents iz~ dish washers, sink drains and
laundry washers, and ss~ane are
also suggested for removing mildew.
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Additives for stabilizing aqueous hypochlorite solutions against decomposition
caused by
temperature and other aging effects during storage are known. For exxarnple,
United States Patent
4,071,463 (Steinhauer) discloses for use as an alkali metal hypochlorite
stabilizer, certain
synthetic detergents (e.g., alkali metal alkyl sulfates and alkyl aryl
sulfonates) and United States
Patent 4,898,681 (Burton), discloses calcium Chelate of disodium
ethylenediaminetetraacetic acid
for such stabilizing use.
Although the known aqueous alkali metal hypochlorite cleaning compositions are
useful
for removing some mildew stains from surfaces, improvemems are desired to
greatly increase the
cleaning efficiency of mildew staiu removal so that scrubbing andlar high
pressure water-hosing
normally is not required after the cleaning composition is used on a stained
surface.
SUMMARY OF THE INVENTION
'The present invention provides a cleaning composition for removing stubborn
mildew
from a surface normally without scrubbing. The cleaning composition is of the
type that
comprises an aqueous solution of an alkali metal hypochiorite, an alkaline
builder that maintains
the solution at a pH of at least 11, and a hypochlorite-compatible surfactant.
The cleaning
composition is a fluid foam that has, in combination, as measured by rnetk~ods
described
hereinafter, (a) a precursor-solution relative viscosity of no greater than
three, preferably in the
range of 0.8 to 1.5, (6) a syneresis value in the range of 2 to 40°10,
preferably in the range of 10 to
30%, (c) a foam horizontal thickness half life of at least 12 minutes,
preferably at least 15
minutes, and (d) a vertical-surface clingability of at least ? minutes,
preferably at least 10
minutes. A preferred alkali metal hypochlorite is sodium hypochlorite which is
present in a
concentration in the range of 1 to 15 percent, preferably 3 to 10%, by total
weight ofthe aqueous
cleaning composition. A preferred alkaline builder is sodium hydroxide or
potassium hydroxide.
Preferably, the aqueous solution of alkali metal hypochlorite is free of
undesired metal ions.
Preferred compatible surFactants are a cocamine oxide, a sodium alkyl
alkanoate and sodium
dodecyl diphenyl disulfonate, present in a concentration range of 0.1 to 10%.
The invention also provides a method for forming the above-described cleaning
composition fluid foam.. The method comprises (a) preparing an aqueous
solution of an alkali
metal hypochlorite, preferably purified of unwanted metal ions, an alkaline
builder that maintains
3o the solution at a pH of at least 11, and a hypochlorite-compatible
surfactant in a container and (b}
vigorously agitating the solution in the presence of a gas with mechanical
stirrers or by
fluidiclpneumatic action of a fluid jet, preferably produced by a mechanical
breakup actuator of
an aerosol dispenser in the presence of propellant. Preferably, the foam is
produced with a low-
boiling hydrocarbon propellant in an aerosol dispenser made of materials
compatible with the
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aqueous solution. Pxeferred propellants include propane, butane, isobutaue and
mixtures thereof
in a concentration of 1 to 15%, preferably 3 to 10%, by weight ofthe aqueous
cleaning
composition. in the preferred aexosol dispenser, all parts and surfaces that
contact the aqueous
cleaning composition are of hypochlorite-compatible metal, rubber ox plastic.
l5re~erred plastic
materials are polyethylene, polypropylene, nylon and polyester.
BRTEF DESCRIPTION OF THE DRAWINGS
The invention will be more readily understood by reference to the accompanying
dxawings, in which:
FIG.1 is a side view of a graduated glass cylinder 10 in which the heights of
foam 11
and separated liquid 12 are measured during a "syneresis value" test and
wherein ho is the
original height of the foam in the filled cylinder at the start of the test,
and hl and hz are
respectively the thickness of the separated liquid layer and the thickness of
the foam layer at a
given time during the test; and
FIG. 2 is a schematic representation of an aerosol dispenser suitable for
dispensing an
aqueous foam of the invention, wherein 20 is a cylindrical container, 21 is a
hypochlorite-
compatible inner liner of the container, 22 is a sinnilarly lined cover in
which is mounted a valve
assembly comprising housing 23, gasket 24, spring 25, hollow valve stem 26,
button actuator 27,
exit nozzle 28, and dip tube 29, and wherein 30 is a mixture of aqueous
hypochlorite solution and
propelIarrt liquid, 4Q is a space filled with propellant vapor, and 50 is a
layer of liquid propellant,
normally present before the dispenser is shaken prior to u$e.
DETAILED DESCRIPTION OF PREFERitED EMBOI?IMENTS
The following detailed description of preferred embodiments ofthe invention is
included
fox purposes of illustration and is net intended to limit the scope of the
invention. The scope is
defined by the claims appended below.
Definitions
For convenience and clarity, the meaning will now be given of several terms
and
characteristics that are used to describe the invention. Descriptions of tests
employed to
quantitatively measure some ofthe characteristics follow the list of
definitions.
"Mildew" refers to any one or combination of mycological stains including
household mildew,
algae, fungus, spores etc.
"Stubborn mildew stain" xefers to gray or black mildew which grew on a surface
over a long
period of time during which the mildew color typically changed from yellow to
pink to green and
finally to gray and black.
3
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"Alkaline builder", also referred to in the art as an "override substance", is
a chemical buffer
that maintains an aqueous alkali metal hypochlorxte solution at a pH of at
least 11, and helps
prevent decomposition of the solution, thereby increasing the shelf life ofthe
solution.
"Compatible" means that a particular material or substance being referred to
does not
substantially adversely affect cleaning efficiency of a fluid foam of the
invention or the
performance of its dispenser device.
"Clingability" refers to the ability of a foam to cling or adhere to a
vertical surface, measured
as described herein below.
"~sterizer" refers to an electric mixer, usually used in food preparation, but
employed herein
1~ to pxepare fluid foams of various compositions, as reported in the
Examples.
"Pouched dispenser" or "homer dispenser" refers to a pressurized dispenser in
which the
aqueous hypochlorite solution is contained inside a pouch made of materials
compatible with the
sQiution, the pouch itself being suspended from and sealed to the dispenser
valve and not in
intimate contact with the inner walls of the dispenser.
15 "Stabilized hypochlorite" or "purified hypochlarite" refers to alkali metal
hypochlorite
solution from which detrimental impurities, including meal ions such as
aluminum, copper and
iron, were removed by filtration or by chelatioxl or by other techniques.
"Cleanability" refers to a numerical ranking of the degree of whiteness or
color shade change
that occurs as a result of the application of a cleaning composition to a
stained panel, measured as
20 described herein below.
"Precursor solution" refers to the cleaning composition of aqueous solution of
alkali metal
hypochlorite, alkaline builder, urfacrarrt and optional additives, prior to
conversion of the
cleaning composition into a fluid foam.
"Syneresis value" is a measure of the amount of liquid that separates from a
fluid foam,
25 measured as described herein below.
"Horizontal thickness half life" is the time interval required for an aqqeous
foam to lose 50%
of its thickness, as measured in the syueresis value test.
"Actuator with mechanical breakup" refers to a known actuator which
incorporates a feature to
reduce spray particle size (e.g., a circular or near circular swirl chamber,
or a channel with several
30 tangential entries).
Test Procedures
Cleanabilitv. The cleaning effectiveness of different products is tested on a
landscaping
timber that has stubborn mildew stains distributed over its surface, The
stained landscaping
timber typically measures 240 em. (~ feet) in length and about 7.2cm. (3-in)
by 10.2 cm. (4 inch)
4
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in rectangular cross section with rounded edges, Landscaping timbers of this
type frequently are
found in yard or garden areas around residential homes. When exposedto the
environment of a
humid climate for a long time (e.g., a few years), the timbers become covered
with a layer of a
high intensity grey or black, stubborn mycological stains. Such stained
timbers are ideal for
s running a large number of tests to evaluate and compare, side by side, the
effectiveness of
differed mildew removers. Irt preparation for a series of cleanability tests,
a landscaping timber
is pieced harizonta3ly on the ground with the longer side of its cross section
perpendicular to the
ground. The timber is then marked with vertical lines to divide the timber
into test panels of
about 5-cm width. The panels are numbered for identification. Every other
panel is used as a test
IO panel on which a sample of the cleaning composition being tested is placed
for a predetermined
period of time. At the end of the time period, the test panel is rinsed with
water. The non treated
stained alterna~Ge panels on each side of the test panel serve as controls.
At the completion of the tests and the rinsing with water, the test panels axe
allowed to
dry without scrubbing. Then, the cleanliness of each test panel is measured
relative to its adjacent
I5 controls by a method known as "Gray Scale for Evaluating Changes in Color",
referred to as ISO
International Standafd R105II, Part 2. According to this method, the
difference between the color
ofthe test item and its adjacent controls is matched with the closest co~rast
between gray colox
pairs printed on a standard template. The scale on the gray scale template
extends from 1 for the
largest difference in color contrast to s for na visible contrast difference,
with fractions in
20 between making a total of 10 gray scale panel pairs. By use of standard
tables published with the
Gray Scale method, the numbers obtained from the gray scale comparison are
converted to "Total
Color Difference" ea~pressed in "CIE Lab Units". The total Color Differences
range from zero
CIE Lab Units fpr a gray scale rating of s to 13.7 CIE Lab Units (reported
herein for simplicity as
14) far a gray scale rating of 1. In the examples below, all cleanability
ratings are reported in CIE
2s Lab Units.
Relative Viscosity. The relative viscosity of an aqueous precursor solution
(i,e., the
aqueous solution of alkali metal hypochioxite, alkaline builder, suxfactant
and optional additives,
prior to conversion into a fluid foam cleaner) is measured herein by a simple
laboratory apparatus
having a vertical arrangement of a right conical plastic funnel with an outlet
tube attached and
30 sealed to a plastic capillary tube. The internal diameter ofthe circular
upper end ofthe funnel is
S.I cm. The diameter afthe circular lower end ofthe funnel is 0,64 cm. The
distance between
the upper and lower ends ofthe conical portion ofthe funnel is of 4,s cm. An
exit seem extends
2.s cm from the lower end of the funnel, A 17.8-cm long capillary tube of 0.1-
cm internal
diameter is inserted 2.0 cm into the end of the funnel stem and sealed
thereto. The total capacity
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of the apparatus from the upper end of the funnel to the outlet end of the
capillary tube is 35 cm3.
All flows through fine apparatus are measured at 21°C. To determine the
relative viscosity of an
aqueous liquid, (a) the apparatus is first completely Filled with the liquid,
(b) the time required for
the liquid to flow through the apparatus is measured and (c) the time required
fnr the same
volume water to flow th~augh the apparatus is measured. The relative
viscosity, RV, of the
aqueous liquid is defined as the ratio of tree, t0 twa~r a here ttest is the
measured time for the test
liquid to flow through the apparatus and ta,ater is the measured time for
water to flow through the
apparatus. Relative viscosities at different shear rates are obtained by
repeating the procedure
with capillaries of different dimensions. The relative viscosities reported
herein were measured
on precursor sohition at a shear rate of 7 sec''.
Svneresis Value and Foam Horizontal 'Thickness Half Iife. The syneresis value
and the
horizontal thickness half life of a fluid foam are measured with a graduated
plastic or glass
cylinder, as depicted in FiG.l. The cylinder is initially filled completely to
its full internal height
howith a cleaning composition foam and the cylinder is placed upright on a
horizontal surface.
I5 The thickness hz of foam layer 11 and the tliiclmess hl of separated liquid
layer 12 are measured
as functions of time during the test. The "synexesis value", SV of the fluid
foam, is expressed as
a percentage of the initial thickness of the foam and is calculated bythe
formula, SV =100(hilho).
Because the syneresis value rarely changes after 45 mimutes of testing, the
syneresis values
reported herein were based an measurements made at about 45 minutes. A graph
is prepared of
2o the thickness ha of the foam, expressed as a % of the initial foam
thickness ha, versus time and the
horizontal thickness half life of a cleaning composition fluid foam is
determined as the time
(measured from the start of the test) at which 100(h~) equals 50%.
Vertical Surface Clingability. '"Flee ability of a fluid foam or other aqueous
cleaning
composition to cling to a vertical surface is measpred as follows. A test
fluid foam or aqueous
25 liquid cleaner is sprayed oiato ar otherwise applied in sufficient quantity
to substantially cover a
vertical 7.2-em, by 10.2 em. test panel on one side of a landscaping timber
(of the type described
above in the "cleanability" test). With increasing time after cleaner
application, the area covered
by the test cleaning composition shrinks. A graph is constructed of the % of
the area covered by
the shrinking test material as a function oftime after application. The
vertical clingability
30 reported herein is defined as tl~e time required for the area of the
applied test material to shrink to
50% of its initial area coverage.
Fluid Foams
According to the present invention, a typical cleaiu~ig composition is a fluid
foam that
contains (a) an aqueous solution of an alkali metal hypochlorite, preferably
sodium hypvchlorite
6
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or potassium hypochlorite in a concentration range of 1% to 15% by total
weight of the solution;
(b) au alkaline builder, preferably sodium hydroxide or potassium hydroxide in
a concentration
range of 0.01 % to 1.0% in excess of amount needed to maintain the aqueous
solution at a pH of at
least 11, (c) a hypochlarite compatible surfactant, in a concentration range
of 0.1 to 10%, such as
a cocamine oxide, and (d) other optional enhancing agents, such a compatible
fragrance, a soap-
scum remover, such as tri-sodium phosphate, in a concentration range of 1 % to
10%, and a
hypochlorite stabilizer, such as a chelating agent in a concentration range of
0.005%to 0.25%.
The cleaning composition fluid foam of the invention has a combination of
characteristics that
provides greatly improved mildew-removing efficiency to the cleaner. The
characteristics of the
14 cleaning composition foam are (a) a relative viscosity afthe aqueous
precursor solution ofno
greater than 3, preferably 0. ~ to 1.5, (b) a foam syneresis value in the
range of 2 to 40%,
preferably 10 to 30%, (c) a foam horizontal thickness half life of at least 12
minutes, preferably at
least 15 minutes, and (d) a foam vertical-surface clingability of at least 7
minutes, preferably at
least 10 minutes. Because of this combination of characteristics, the cleaning
composition fluid
IS foam ofthe invention brings into contact with a stained surface
substantially larger amounts of
stain-removing alkali metal hypochlorite for longer times than is provided by
known aqueous
cleaning compositions of equal hypochlorite concentration applied to a stained
surface in the
form of a sprayed liquid, a short-lived foam, a thickened liquid or a gel. The
superior cleaning
efficiency of the fluid foams of the invention compared to known cleaners of
similar composition
20 is believed to be a result of the liquid-rich cells o~the fluid foam of the
invention clinging
strongly to the surface being cleaned and the cells breaking up slowly so that
a continuous source
of the alkali metal hypochlorite is efficiently delivered to the stained
surface. Thus, a fluid foam
of the invention has a longer contact time with the stained surface and
provides a greater amount
stain-removing agents to react with the stain.
25 As shown in the Examples below, the present inventor found that the fluid
foams of the
invention provide better cleaning without scrubbing than any of the known
hypochlorite-
containing cleaners he tested. Substantially the same superior cleaning
results, as were obtained
in the cleaning ofthe mildew covered surfaces of the landscaping timbers, are
obtained when the
fluid foam cleaning compositions of the invention are applied to stained
surfaces of painted
30 wood, plastic filxa, cement, plaster, fabric or the like. In addition, the
cleaning composition fluid
foam of the invention, even without the i~iclusion of a fragrance, was found
to mask to a
substantial degree, the smell of the alkali metal hypochlorite. Also, during
application of the fluid
foam cleaning composition of the invention to a stained surface, the typically
opaque white color
of the fluid foam provided an easily seen indicator of whether the cleaner had
missed any
7
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particular area of the surface. The present inventor further found that fluid
foam cleaner of the
invention also removed soap scum, dirt and oily stains.
Fluid foams having characteristics outside the combination of characteristics
set fazth
above for the fluid foam of this invention are deficient in their ability to
remove stubborn
mycological end mildew stains without brushing ar scrubbing. For example, a
thick liquid having
high relative viscosity is not readily formed into a fluid foam cleaning
composition ofthe
invention and is not readily removable from a surface by rinsing. Typically ,
when such a thick
liquid is used to clean a surface, scrubbing is required to remove a layer of
the cleaner that
remains on the surface even after rinsing. A fluid foam having very low
syneresis value does not
clean well because it does not carry and release an adequate amount of the
active cleaning agent
to the stained surface, even ifthe vertical clingability of the foam is high.
Also, a foam that has
an excessively large syneresis value often is too thin aid slippery, which
prevents the foam from
adhering to the stained surface long enough to accomplish the cleaning. A foam
having very
short horizontal thickness half life or a very law vertical surface
clingability also leaves the
stained surface too quickly to allow for adequate cleaning.
Producing-and Dis ep nsin~ Fluid Faam
The process for producing a cleaning composition fluid foam ofthe invernaion
typically
comprises two-steps. First an aqueous solution is prepared containing an
alkali metal
hypochlorite, an alkaline builder that maintains the solution at a pH of at
least I 1, and a
hypochlorite-compatible surfactant, each in the desired concentrations recited
herein before.
Then the solution is vigorously agitated in the presence of a gas. The
vigorous agitation can be
achieved with mechanical stirrers, but preferably is provided by the
fluidie/pneumatic action of a
fluid jet, such as is produced by a mechanical breakup actuator of an aerosol
dispenser in the
presence of propellant. Preferably, the foam is produced with a low boiling
hydrocarbon
propellant in an aerosol dispenser made of materials compatible with the
aqueous solution.
Preferred propellants include propane, n-butane, isobutane and mixtures
thereof in a
concentration of 1 to 15% by the weight of the aqueous solution. Parts and
surfaces of the
aerosol dispenser that contact the aqueous solution are of hypochlorite-
compatible metal, rubber
or pla~titc.
The preferred method of preparing and dispensing a fluid foam ofthe invention
will now
be described with particular reference to the aerosol dispenser depicted in
dig. 2. An aqueous
solution of alkali metal hypochlorite, alkaline builder and surfactant, in
accordance with the
concentrations required for the fluid foam cleaner of the presenx invention,
is mixed and placed in
the container 9fthe aerosol dispenser. The outer wall ofthe dispenser
container typically is of a
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metal, plastic or glass of sufficient strength to withstand the internal
pressures expected during
use. The container has an inner liner made of hypochlorite-compatible glass or
plastic.
Polyethylene and polypropylene are pre~~rred liner materials. A container
particularly suited for
use with the aqueous solutions is commercially available from ALCAON
PACT~AG1NG of
ALgroup Wheaton of Netherlands.
The aexosol dispenser, as depicted in FIG. 2, comprises a cylindrical
container 20 having
a cover (also called a "mounting cup") 2Z attached to the top of the
container. The container has
an inner liner insert 2I of hypochlorite compatible material. Cover 22 has a
hypochlorite-
compatible material laminated to its inner surfape. Valve components ofthe
aerosol dispenser ire
IO pre-assembled to form a valve assembly unit, which includes housing 23,
valve stem gasket 24,
spring 25, valve stem 26, actuator button 27 containing nozzle 28, and dip
tube 29. The valve
assembly unit is inserted through an apening in the center of cover 22 and is
attached to the cover
to form a valve/cover assembly. An aqueous precursor solution is pxepared,
mixed and loaded
into co~ainer 20. Then, the pre-assembled valve/cover assembly is installed in
the container.
I5 The hypachlorite-cornpa~ible material laminated to the circumferential edge
of cover 22 is
brought into contact with the upper rim of hypochlorite~compatible inner liner
21 of container 20
and then the circumferential edge of cover 22 and the top edge of container 20
are mechanically
crimped together, so that the hypochlorite-comopatibIe materials ofthe cover
laminate and the
co~ainer inner liner form a seal. Optionally, a cover-,sealing gasket, not
shown in Fig.2, can be
20 installed. All parts of the aerasol dispenser are made of materials
compatible with aqueous
hypochlorite solution. A suitable design of spray valve assembly for
installation in the cover of
the aerosol dispenser is commercially available from Precision Valve
Corporation, Yonkers, New
York or from Seaquist Perfect Dispensing of Gary, Tndiana. In such spray valve
assemblies, the
housing and valve stem can be made of nylon, the dip tube and actuator button
of polyethylene or
25 polypropylene, the valve stem gasket of butyl rubber U~133, of an
ethylene/propylene copolymer
or of Viton synthetic rubber (from Dupont Dow Elastomers LLC of Wilmington,
Delaware) and
the coil spring of passivated stainless steel, tantalum or titanium.
Typically, the cylindrical
container and cover can be made of aluminum, steel ar tin plate, the cover
being laminated with a
fihn of polyethylene or polypropylene on its inner surfaces and the cylinder
having an inner liner
30 insert of polyethylene or polypropylene.
After the dispenser container is loaded wifih solution and the cover and spray
valve
assembly installed arid sealed, propellant (usually as liquid) is injected
under pressure through the
valve assembly into the container where part mixes with aqueous solution 30,
part floats as a
liquid layer 50, atop the solution, and part forms a gaseous phase that fills
pace 40, thereby
CA 02480893 2004-09-29
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providing the pressure needed to drive the solution/prapellant mix through the
valve assembly
when the valve is opened. Preferred propellants include propane, butane,
isobutane and mixtures
thereof in quantities amounting to 1 to 15% of the weight of the aqueous
solution. Before
opening the valve, the dispenser is shaken to mix the propellant with the
aqueous liquid in the
container. Then, depressing actuator button 27 against spring 25 causes gasket
24 to flex and
expose the orifices in the wall of valve stem 26 to pressure, which allows the
mix of cleaning
composition solution and liquid propellant to flow though valve stem 26,
through the passages of
button actuator 27 and through nozzle 28. Nozzle 28 has a mechanical break-up
actuator insert
located just upstream of the nozzle exit. Typically, the mixture emerging from
the actuator
nozzle is like a mist that when dispensed onto a surface, converts almost
imrnediatelyto fluid
foam ofthe invention.
Within the actuators of the aerosol dispensers, certain design features can
improve
sprayed foam formation. Such features include, upstream ofthe exit nozzle,
mechanical breakup
mechanisms to reduce spray particle size. Typical break-up mechanisms include
a circular or
near circular swirl chamber, one or more tangential entries to a chamber,
orifices, screens, andlor
special exit nozzles. The aerosol dispenser can also include an extension
tube, not shown in
Fig.2, which extends from the exit of button 27 and has a mechanical break up
orifice located at
the exit end of the extension tube.
EXAMPLES
The following examples illustrate the preparation of cleaning composition
fluid foams of
the invention and demonstrate the unexpectedly large advantage in mildew
removal that these
fluid foams possess over known hypochlorite-containing cleaners, as well as
other hypochlorite-
containing cleaners that are outside the invention. The reported results are
believed to be fully
representative of the invention, but do not constitute all the tests involving
the indicated cleaning
compositions. In the examples, all concentrations of ingredients, unless
specifically stated
otherwise, are by % of the total weight of aqueous solution.
In tJxe Examples, fluid foam of the invention was produced by vigorously
agitating
aqueous alkali metal hypochlorite solution, while in contact with a gas, such
as air, or a low
boiling liquid hydrocarbon propellant. Vigorous agitation was produced by
mechanical or
fluidic/pneumatic means. Test foams of the invention prepared by vigorous
mechanical agitation
of liquid solution in the presence of air were produced in an 800watt AC
"Osterizer"
manufactured by Oster Corporation of Miluakee, Wisconsin, having a 1.2-liter-
capacity glass
container. The foam produced by the Osterizer was dispensed to a test panel
surface by pouring,
by brushing or with a spatula. When vigorous agitation was provided by an
aerosol dispenser, a
CA 02480893 2004-09-29
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dispenser of the general type illustrated in FICs. 2 was employed. When a
commercial
hypochlorite-containing cleaning composition was tested, the cormnercial
product was employed
in accordance with its manufacturer's instructions and usually applied to the
test panel with the
manufacturer-supplied plastic hand pumped spray nozzle.
The Examples, especially Examples 2 and 3, demonstrate that hand pumped
dispensers of
the type common in the art, do not provide sufficiently intense mechanical
agitation to produce a
fluid foam of the invention and as a result do not provide the improved
cleaning efficiency of the
fluid foams of the invention..
Example 1
to This example quantitatively demonstrates the greater mildew-removing
effectiveness of
aqueous hypochlorite-comaining cleaning compositions applied as fluid foams
ofthe invention
over the same hypochlorite-containing compositions applied as liquids. Side by
side comparisons
were made o~the cleaning effectiveness on the same mildew stained landscaping
timber.
Five different aqueous solutions were prepared. The solutions had spdium
hypochlorite
IS concentrations of 1, 2, 3, 4 and 5 %. Each solution also contained a 0.5 %
concentration sodium
hydroxide alkaline builder to maintain the aqueous solution at a pH of at
least 1 I and a I .5
concentration ofnon-ionic surfactant "Barlox I2"cocamine oxide (available from
Lonza
Speciality Chemical Company of New Jersey). The surfactant has an average
molecular weight
of 249 and is a mixture of N,N dimethyl-1-dodecylamine-N-oxide, N,N-dim~ethyl-
1-tetradecyt-
20 amine-N-oxide, and N,N-dimethyl-I-hexadecylamine-N-oxide. A 200-cm3 portion
of each liquid
solution was converted to a fluid foam of the invention by vigorous mechanical
agitation of the
solution ire an Osterizer set at a high (i.e., "whip" setting) for 20 seconds.
Then each liquid
solution and its corresponding same composition fluid foam were applied to
side by-side
cieanability test panels of a landscaping timber stained with stubborn mildew.
The total color
25 difference produced on each test panel by the liquid or foam was measured
five minutes after
application of the liquid or foam to the panel. Test results are summarized in
the following table.
Table I Cleanabilit~f liquid vs fluid foam~ochlorite-containing cleaners
NaOCI Cleanabilit~ftotal color difference)
Sam Ie %Conc. Foam Liauid Foarn advantage
30 1 1,0 4.I 3.4 20%
2 2.0 4.8 3.4 41%
3 3.0 6.8 4.1 66%
4 4.0 9.6 4.1 134%
5 5.0 14 4.I 241%
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The above-summarized cleanability measurements show that fluid foams of the
invention
have a large mildew stain-removing advantage over corresponding comparison
liquids having the
same chemical composition. In the table, the advantage is expressed as a %
difference between
the cleanability rating of the foam versus that of the corresponding liquid.
The results also
demonstrate the larger advantage of preferred hypochlorite concentrations of
at least 3%. Note
particularly the 241 % advantage of nearly 10 gray scale color difference
units for the 5%
hypochlorite concentration in the fluid foam cleaner of the invention over the
corresponding
liquid cleaner.
l0 Example 2.
Tn this example, a series of fwe-minute cleanability tests were performed with
commercially available aqueous hypochlorite-containing cleaners. Test panels
on the same
mildew-stained landscaping timber as used in Example I were treated in this
example in order to
compare the commercial cleaners to cleaning composition fluid foams of the
invention. The
15 commercial cleaners are designated with lower case letters.
Table iI Cleanabiitv ratia~ of commercial aqueous hypochlorite cleaners
Cleanability
Commercial Product Description Spray an~lied as tin
a. Dow soap scum plus mildew stain remover (3%NaOCI) a thin foam 2.5
2o b. Clorox Tilex instant mildew remover (1.65%NaOCI) a liquid 0
c. Clorox cleanup gel* a gel 0
d. Meriplus Tile plus instant mildew stain z~emover'~ a liquid 4.0
e. Beneckiser Scrub free mildew remover* a liquid 0
Clorox liduid bleach (5.25% NaOCi) a liquid 4.0
2~ * the asterisk means that the product contained an unspecified
concentration of hypochlorite
Note that none of the above-listed commercial products cleaned the stained
timbers
nearly as well as the foam cleaner oftlxe invention. Clorox liquid bleach, the
product designated
"f' in the table, with a 5.25% NaOCI concentration was the best performing
commercial product,
but its cleanability rating was only 4.0, in contrast to a rating of 14.0 for
a foam of the invention
30 having an NaOCI concentration of 5% (see Table I).
Anather series of cleanability rating tests, performed with different (from
the above-
listed) commercially available hypoehlorite-containing aqueous cleaners,
showed, that no product
even matched the cleanability rating of the Clorox liquid having a 5.25% NaOCI
content, which
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still was much inferior in cleanability rating to the foams of the invention.
Thus, these tests
again showed the great superiority in cleaning effectiveness of the cleaning
composition fluid
foams of the invention over currently available commercial products. Tn these
two series of
cleanability tests, more than a dozen commercially available hypqchlorite-
containing cleaners
were tested. It was further noted that each of the commercial cleaning
products had a vertical
clingability and a horizontal half life that were very much smaller than those
of the fluid foams of
the invention of Example 1.
Example 3
Tn this example, the cleanability rating of two cleaning composition fluid
foams of the
invention were compared with an aqueous sodium hypochlorite composition that
was thickened
with a visco-elastic surfactant.
A thickened aqueous composition, which was substantially the same as the
composition
disclosed in Example 2 of U.S. Patent 4,800,036 (Rose), was prepared as
follows. To 544.2
grams of a 5.25% active NaOGI aqueous bleach (sold by Clorox Corporation),
441.5 grams of
1S distilled wat$r were added. Then, 7.14 grams of hexadecyltrimethlammonium
bromide and 7.14
grams of sodium p toluene sulfonate were added to the aquecaus bleach. The
Last two solid
ingredients were dissolved in the liquid by stirring with a spatula for about
30 minutes. The
resulting solution, which was transferred to a plastic bottle, had calculated
concentrations of
2.86% NaOCI; 0.71°J° hexadecyltrimethylammonium bromide, 0.71%
sodium p toluene sulfonate
and 95.72% water. The solution was yellowish, very thick (viscous) compared to
water and
tended to form clumps or streaks of even thicker liquid dispersed in the
solution when the
container was shaken. Cleanability tests were performed by applying this
aqueous formulation to
the test panels in three different ways, namely (1) as liquid solution poured
onto the test panel, (2)
as a spray, dispensed from the same hand-pumped spray foaming device as was
used for
commercial sample "a" of Example 2, and (3) as a foam prepared by whipping a
200-cm3 portion
of the solution for 30 seconds in the Osterizer immediately before being
applied to a test panel.
These three test samples were designated Tl, TZ and T3. Note that a thickened
foam such as T3,
which was prepared in the Osterizer, is not disclosed or suggested in U.S.
Patent 4,800,036.
The aqueous cleaning composition fluid foams of the invention with which the
above-
described thickened formulations were compared were designated as Samples 6
and 7. The
samples contained 0.5 and 0.3% NaOH alkaline builder respentively and 1.5%
Barlox coeamine
oxide surfactant. NaOCI concentrations in Samples 6 and 7 were 5.0 and 3.0 %
respectively.
Precursor solutions of Sarnpies 6 and 7 had relative viscosities in the range
of 1.1 to 1.5. Samples
6 and 7 were -then vigorously agitated in the Osterizer to produce fluid foam
of the invention.
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The fluid foams of samples 6 and ?' had vertical surface clingabilities in the
range of 7 to 12
minutes and horizontal half fifes of greater than 15 . In contrast to the
fluid foams of the
invention, each of the thickened samples had a precursor solution of vastly
higher relative
viscosity (e.g., at least S00% the viscosity of water) and a very short
vertical clingability of less
S than 20 seconds.
'flee cleanability ratings in 10-minute tests ofthe three thickened
samples,Tl, T2 and T3,
and the fluid foams of the invention, Samples ~ and 7 were measured, side by
side, on the same
stained landscaping timber. The results of the measurements are summarized
below in Table III.
Table flI Cleanability rating flf thickened cleaners vs. foams of invention
IQ % Na0C1 Cleanability Rating
Of invention: Sample-6 5.0 14
Sample 7 3.0 9.6
Thickened: Liquid Tl 2.86 4.8
spray T2 2.86 4.g
I5 4sterizer foam T3 2.86 ' 6.8
Table III shows that the applications of the thickened liquid and spray (T1
and T2
respectively) performed poorly in the cleanabitity tests compared to the fluid
foams of the
invention. Even when the thickened formulation was vigorously agitated in the
Osterizer to form
a foam, the cleanability ratings of the thickened foam was much inferior to
the foams of the
20 invention. It was also noted that the thickened liquid and spray samples
had a consistency
resembling that of an uncooked beaten egg and had a tendency to run down and
slip off the
vertical panels. Further, after the tests panels were rinsed with water, some
amounts of sticky
film remained on the panels and could not be rinsed away without scrubbing or
brushing. By
contrast the surfaces treated with the foam of this invention were completely
cleaned by simple
25 rinsing with room temperature water with no residues left behind.
Example 4
This example illustrates the use of an aerosol dispenser of the general design
depicted in
'Fig.2 to produce fluid foam cleaning composition ofthe invention. An, aqueous
solution was
prepared to contain S% sodium hypochlorite, O.S% sodium hydroxide alkaline
builder, and 1.5%
30 Barlox-12 surfactant which contains 30% cocamine oxide in water. A 320-cm3
volume of the
aqueous solution was loaded into each of several aerosol disp~nnser
containers. Each dispense
measured 1S cm high by 6.3 cm in diameter. The internal surfaces ofthe
containers were epoxy-
coated. The dispensers were equipped with valves and actuators of the
mechanical break-up type
having an orifice diameter of 0.045 cm (0.018 inch). One of three different
hydrocarbon
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propellant mixtures was loaded into each container; namely; (1) AERON~ NP-31
consisting of
81.3 % n-butane, 16.6 % propane and 2.1 % isobutane, and having a nominal
vapor pressure of
225 KPa (33 psig;), (2) AERON~ NP-46 consisting of 68.5 % n-butane, 31.5 %
propane, and
having a nominal vapor pressure of 317 KPa (46 psig); and (3) AERON~ NP-70
consisting of
42.5 % n-butane and 57.5 % propane and having a4 vapor pressure of 483 KPa (70
psig). The
AERON~propellants were obtained from Diversified Propellant Company
International, Inc.,
U6A. All percentages far the propellant compositions are in ~i~.ole %. The
containers were
loaded to provide propellant concentrations of 5, 3, 2 and 1.25 % by total
weight ofthe aqueous
solution. The foam properties and cleanability ratings of the aerosol-
dispenser- produced fluid
foams were then measured. The measurements showed the following:
(a.) At propellant concentrations of 5%, the dispensed foam was very thick and
had
relatively low levels of' syneresis iwthe range of 2 to 3%. Adequate, but
relatively low,
cleanability ratings in the range of 5 to $ were obtained in the I O-minute
cleanability tests.
(b.) At lower propellant concentrations in the range of 1.25 to 3%, good foams
of the
invention were obtained. Each foams had a syneresis value in the range of 13
to 25%; a vextical
wall clingability in the range of 11 to 2Q minutes; a horizontal foam
thickness half-life of greater
than 60 minutes and a I O-minute cleanability ratings in the range of I2 to
14.
(c.) Although the aqueous hypochlorite-containing solutions used in these
aerosol
dispensers initially provided highly satisfactory foams and corresponding
cleanability ratings,
because of the materials of construction ofthe aerosol dispensef eontainexs,
within three days
after filling the containers, leaks developed in the dispensers.
Further tests, in which similar aerosol cans were constructed with liners,
gaskets, dip
tubes and other parts of different materials, resulted in identifying
preferred materials for all the
parts of the aerosol dispensers. The preferred materials, as set forth above
in the detailed
description of the invention, were compatible with the aqueous hypochlorite
solutions and
thereby permitted the solutions to be stored in the dispenser for long periods
of time.
Esample 5
This example illustrates the use of a pouched or barrier dispenser as an
aerosol dispenser
system for producing fluid foam of this invention. In this dispenser system,
an aqueous
hypochlarite solution and propellant are injected inside a flexible pouch
suspended from the valve
inside the dispenser container and the space between the pouch and the wall of
the container is
filled with nitrogen or air. Two pouches of different material were tested. In
each test, the pouch
was attached to an aerosol valve assembly similar to the type depicted in the
dispenser of dig. ~.
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WO 03/085073 PCT/US03/09641
In the first test, the pouch was made of a plastic film that was Iined with a
layer of nylon
polymer. The pouch was filled with. the same composition aqueous hypochlorite
solution as was
used in Example 4, The solution contained 5% sodium hypochlorite, 0.5% sodium
hydroxide
alkaline builder, and 1.5% Barlox-12 surfactant. Pressurized air filled the
space between the
pouch and tb:e inner wall of the container. This pouched dispenser system
initially produced good
quality foam having satisfactory cleanability ratings, but after several days
of storage, the system
developed leaks.
In the second test, the pouch was constructed fxom two layers of plastic film
between
which was a layer of aluminum foil. This pouch had a capacity of 215 cm3. The
internal volume
IO ofthe container was 329 crn3. The pouch was filled with 202 grams of
solution ofthe same
composition as was used in the test described in the preceding paragraph. The
space between the
pouch and the walls of the dispenser container was filled with nitrogen at a
pressure of 172 i~Pa
absolute (25 pale). A charge of 6 grams of pressurized propellant AERON~' hIP-
46 (consisting of
68.5 male % n butane and 31.5 mole % propane) was injected into the solution
to provide a
15 propellant concentration of 2.96% in the solution. After the contests of
the container were
shaken to assure full mixing, the solution was dispensed through the actuator
to the suzfaee of a
mildew stained landscaping timber for cleanability rating. A fluid foam,
cleaner of the invention
was obtained. The 10-minute cleauability rating was 14 on the 7~' and 8'''
days after the dispenser
had been filled. The rating was 9.6 on the 47'~ and 815' day after filling. At
47 days after filling,
20 the syneresis value was 24°l° and the vertical area
clingability was I4 minutes.
Example 6
In this example, evaluations were made of the effectiveness of different
methods of
stabilizing aqueous h~pachlorite solutions against decomposition during
storage, as measured by
changes in the cleanability values of fluid foams of the invention. Earlier
tests and the preceding
25 examples illustratedthe needta employ dispensers constructed ofhypachlorite-
compatible
materials and to use hypachlorite-compatible surfactants in the solution. It
was also known that
hypochlorite decomposition can be reduced by using an alkaline builder to
maintain the solutions
at a pH of least 11. In this example, the effects ofthe initial hypochlQrite
purity and the use of a
chelating agent were investigated.
3o A first series of tests employed three commercial grades of different
purity aqueous
sodium hypochlorite. These three grades of sodium hypachlorite were obtained
from Olin Chlor
Alkali Products, a Division of Olin Corporation and were designated (1)
HyPure~, of the highest
purity, (2) 1'JF, of intermediate purity and (3) industrial grade, of the
lowest purity. A second
group of solutions was made with the industrial grade aqueous hypochlorites,
but with the
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additioin of Versene~' Ca clielating agent (a calcium chelate of the disodium
salt of
ethyienediamine tetraacetid acid dihydrate (sold by Dow Chemical Company) to
the hypochlorite
prior to storage. The chelating agent was reported to act as a purifying or
stabilizing agent for
aqueous hypochlorite. Samples of each ofthese hypochlorites were stored for 45
and 176 days
and then used to make the test solutions. Each test aqueous solution was
formulated tv contain a
5% concentration of NaOCI, sufficient NaOH to maintain the solution at an
initial pH of at least
11, and a 1.5% concentration of Barlox-12 surfactant. The test solutions were
then converted by
Osterizer agitation to fluid foam cleaners which were then subjected to the
cieanability rating test.
The IO-minute cleanability xatings of the foams are recorded in the following
table.
Table 1V. Stability of foam cleaners
Versene age Cleanability
Na0C1 Grade Concentration ~ ~ Rating
1. HyP~'e~' 0% 45 12 14
0% 176 13 11.5
2. Intermediate 0% 45 14 14
0% 176 7 2.4
3. Industrial 0% 45 11 14
0% 176 7 3.5
0.015% 176 13 14
0.15% i76 7 0
1.0% 176 8 0
The above-summarized data show that the fluid foams of the invention made with
aqueous hypochlorite of the highest purity have very good cleanability ratings
and satisfactory
storage life. The data also show that the use of small concentrations of
chelating agent can
significantly improve the storage life and cleanability rating of fluid foams
made with industrial
grade aqueous hypochiorite. However, increasing the chelatir~g agent
conce~ration from 0.015%
to 0.15% and 1,0% apparantly causes the pH ofthe industrial grade hypochlorite
solution to
decrease significantly below the pH of at least 11 that is needed for
preventing hypochlorite
decomposition.
Additional tests showed that fragrance additives can sometimes detrimentally
affect the
hypochlorite stability. However, in low concentrations such additives can be
used satisfactorily.
Many different embodiments of this invention may be made without departing
from the
spirit and scope of the invention. Therefore, the scope of the invention is
not intended to be
limited except as indicated in the appended claims.
I7
