Note: Descriptions are shown in the official language in which they were submitted.
CA 02454437 2003-12-30
LOW-FOAMING HYDROGEN PEROXIDE CLEANING SOLUTION
FOR ORGANIC SOILS
FIELD OF THE INVENTION
The present invention relates to cleaning solutions and, more particularly, to
low-
foaming cleaning solutions for removing organic soils from hard surfaces.
BACKGROUND TO THE INVENTION
Low-foaming cleaning solutions useful in removing organic soils, including
protein and glyceride-based deposits, are commonly used to clean equipment or
utensils
in the food processing, dairy, health care, dental and veterinary industries.
Equipment
used in the food and dairy industries are often cleaned "in-place" by
circulating a cleaning
solution repeatedly through liquid-carrying pipes of the equipment. In the
cleaning of
medical, veterinary and dental utensils, items are enclosed in a washing
chamber of a
washing machine and sprayed with a wash solution which is collected from the
washing
chamber and recirculated to be sprayed again onto the utensils. This cycle
repeats
continuously for a predetermined period of time or number of cycles. Foam
buildup is
objectionable in the above circumstances as it will increase the amount of
entrapped air in
the recirculating solution. This results in cavitation at the pump or in the
recirculating
pump losing its prime.
Known low-foaming cleaning solutions include chlorine-based cleaners of high
alkalinity, or formulations containing one or more enzymes in a basic
solution. Chlorine-
based cleaners and enzyme-based cleaners work by breaking large protein,
linked amino-
acid, glyceride or fatty acid molecules through oxidation and enzymatic
action,
respectively. The chlorine-based cleaners are based on the high oxidative
power of
chlorine in combination with an alkaline medium to reduce these large soil
particles to
smaller units easily dissolved or emulsified by the surface active species
present.
Similarly, enzymatic cleaners rely on high alkalinity and the chemical
breakdown of
peptide bonds in proteins for dissolution of soils. In both cases, alkaline
conditions result
in saponification of fats in the soil, further contributing to the detergency
process.
Though the actual mechanisms for removing soils differ in both types of
cleaning
solutions, the effects are similar, namely, large particles are broken down
into smaller
more water soluble units that are eventually dissolved in the wash liquor.
1
CA 02454437 2003-12-30
Drawbacks of chlorine-based cleaners are that their use produces large amounts
of
waste water containing high amounts of free chlorine. Furthermore, these
cleaners are
hazardous if mixed with acid solutions (commonly used in two-step
cleaning/sanitizing
procedures in certain applications) to produce highly poisonous chlorine gas.
Also, these
cleaners tend to have very pungent odors, may cause skin and eye irritations,
and may
permanently damage the substrates to which they are applied.
Enzyme-based cleaners, although quite effective in combating protein and lipid-
based soils, generally require high temperatures for effective cleaning.
Furthermore, the
cost of enzyme-based compositions is considerably higher than the cost of most
cleaning
1o chemicals. As a consequence, the cost of cleaning with enzymatic-based
compositions is
generally prohibitive for large-scale applications, and is largely reserved
for specialty
applications in health, veterinary and dental care.
Hydrogen peroxide based cleaners have become favored more recently because
they are odorless, non-corrosive at concentration levels typically employed
for cleaning,
safe to material substrates, their breakdown products (oxygen and water) are
innocuous,
and they can be made at low costs. However, the current art does not
contemplate a low-
foaming, cleaning solution containing hydrogen peroxide which would be useful
in the
applications discussed herein.
Until now, it has been necessary to add high detergency surfactants to boost
the
cleaning power of hydrogen peroxide based solutions, in order to achieve the
same levels
of cleaning efficiency as that of conventional hypochlorite and enzymatic
cleaners.
Surfactants (or surface active agents) work to decrease the interfacial
tension in a solution
to facilitate detachment and emulsification of soils. Unfortunately,
surfactants which
exhibit good detergency will also result in highly foaming solutions, whereas
the use of
non- or low-foaming surfactants generally leads to poor cleaning compositions.
A
common solution to this problem is to add silicone-based foam reducing agents
to the
wash solution. However, these materials tend to allocate and build up in
difficult to reach
places in the equipment and instruments which facilitates proliferation of
microorganisms.
There is therefore a need for a low-foaming cleaning solution which is
effective
against organic-based soils, exhibits favorable environmental profiles, and
possesses a
2
CA 02454437 2003-12-30
minimal or no risk to the user or to the substrates being cleaned. The present
invention is
intended to, at least in part, meet these needs.
DESCRIPTION OF THE PRIOR ART
US 3,969,258 to Carandang et al. discloses an acidic, low-foaming sanitizing
solution designed for use in recirculating systems in the food and milk
industries. The
solution is based on highly foaming anionic surfactants known for their
antimicrobial
properties, and foam suppressing agents consisting of a C8-C1g aliphatic
alcohol, or a C9-
C12 alkyl phenol, in combination with a polyvalent metal compound. The
cleaning
efficiency of the solution is not discussed and the use of hydrogen peroxide
as a cleaning
agent is not taught or suggested.
US 4,878,951 to Pochard et al. teaches alkaline cleaning formulations which
are
low foaming and therefore suitable for the cleaning in-place of equipment
which
circulates food or dairy products. The formulations contain a source of
chlorine (e.g.
hypochlorite) and a mixture of surfactants, one of which is a high-foaming C4-
Cg
alkylated diphenyl oxide sulfonate and the other of which is a non-ionic
surfactantwhich
is stable in the formulation within certain concentration ranges and which
acts to suppress
foaming. The non-ionic surfactant is selected from the group of
polyoxyethylene/polyoxypropylene block copolymers and polyalkoxylated linear
or
branched aliphatic alcohols. The reported solutions are highly alkaline with
caustic soda
used at the rate of 10% w/w of the total solution composition. This reference
does not
disclose or suggest the use of alternate non-chlorine based oxidizers, such as
hydrogen
peroxide.
US 5,855,217 to John describes a device, process and formulation for cleaning
heavily soiled surfaces in the food industry. The device mixes a caustic
detergent
solution and an aqueous solution of hydrogen peroxide to form an unstable,
high foaming
cleaning formulation which is ejected, under pressure, towards the surface to
be cleaned
before the hydrogen peroxide breaks down. The process is based on the
generation of a
cleaning foam containing hydrogen peroxide in an amount from 0.1 % w/w to 1.0%
w/w.
The formulation taught clearly does not have application to recirculating
systems where
the presence of foam cannot be tolerated.
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CA 02454437 2012-04-26
WO 93114183 to The Procter & Gamble Company discloses a detergent composition
which is stable and remains colorless over time. This is achieved by adding
hydrogen peroxide
and a metal sequestering agent to high detergency, high foaming anionic and/or
non-ionic
surfactants. These surfactants do not include low-foaming small chain aikane
sulfonates and
alkylarenesulfonates.
Numerous hydrogen-peroxide based cleaning compositions have been proposed,
none of
which appear suitable for applications involving substrates highly soiled with
protein,
carbohydrate and lipids, where both high detergency and low or no foaming are
required. For
example, US 5,602,090 to Melikyan et al. describes a hard surface cleaning
solution comprising
hydrogen peroxide, D-limoncnc, two anionic surfactants, a non-ionic
surfactant, and deionized
water. Although the low-foaming sodium 1-octane sulfonate (sold under the
commercial name
13ioterge PAS- 8S) is listed as a possible one of the anionic surfactants, the
other surfactant
components are high-foaming.
US 5,891,3 )92 to Monticello et al. teaches an acidic hard surface cleaning
and disinfecting
composition based on hydrogen peroxide as an active disinfecting constituent,
a monohydric
alcohol, a glycol ether or butoxypropanol or propoxypropanol, a non-ionic
surfactant, and an
organic acid. All the non-ionic surfactants listed in this reference are high
foaming.
US 6,110,883 to Petri et al. discloses a hydrogen peroxide-based composition
suitable for
use as a hard surface cleaner or in laundry applications. The composition
further comprises a
surfactant selected from a group of high detergency/foaming anionic, non-ionic
or amphoteric
surfactants.
SUMMARY OF THE INVENTION
Formulations according to the present invention incorporate hydrogen peroxide
and
specific surfactants which exhibit low-foaming properties. The formulations
are designed for
cleaning jobs where foam build up is objectionable and where the control of
microbial
populations is important. The invention provides both a liquid. solution and a
dry particulate
4
CA 02454437 2012-04-26
formulation which may be diluted with water, deionized water, or a mixture
thereof, to form the
liquid solution.. The solution may be in concentrated form for dilution by the
end user or in
ready-to-use diluted form.
Unless otherwise specified herein, all concentration values are expressed in
terms of the
total weight of the solution, or the total weight of the formulation (for dry
particulate
formulations), as the case may be.
Accordingly, in accordance with a first aspect, the invention provides an
alkaline low-
foaming cleaning solution for the removal of organic soils from hard surfaces
or medical devices
or to disinfect hard surfaces or medical devices, having an alkaline pH of
from about 8 to about
11.5, and consisting essentially of:
(a) hydrogen peroxide concentration of from about 2.1 % wlw to about 50% wlw;
(b) at least one builder in a concentration of from about 0.001% w/w to about
50% w/w;
(c) at least one surfactant selected from the group consisting of C3-C8 alkane
sulfonates,
Cl to C4 alkylarenesulfonates, C3-C8 alkyl sulfates, C1-C7 alkyl naphthalene
sulfonates,
polyoxyethylene/polyoxypropylene block copolymers having a polyoxypropylene
molecular
weight of from about 1500 to about 8500, of which less than about 30% of the
total molecular
weight is due to the polyoxyethylene portion, and mixtures thereof, in a
concentration of from
about 0.005% wlw to about 40% wlw; and
(d) at least one diluent selected from the group consisting of deionized
water, water, and
mixtures thereof, to 100% w/w,
The at least one surfactant may be selected from the group consisting of
alkali metal and
ammonium salts of octane sulfonic acid, alkali metal and ammonium salts of
cumene, toluene,
and xylene sulfonic acids, sodium octyl sulfanate, sodium xylene sulfonate,
and a block
copolymer consisting of a polyoxycthylcnc block capped at both ends by
polyoxypropylcne
blocks where the total molecular weight of the polyoxypropylene portion is
1700 and the
polyoxyethylene portion comprises about 20% of the total molecular weight.
5
CA 02454437 2012-04-26
The at least one builder may be a cation sequestering agent which, in turn,
may be
selected from the group consisting of citric acid, glycolic acid,
polyphosphates obtained by the
thermal treatment of monosodium phosphate, amino phosphonic acid compounds
with 1 to 5
phosphonic acid moieties, amino-carboxylic acid analogues of amino phosphonic
acid
compounds with 1 to 5 phosphonic acid moieties, and mixtures thereof. The
polyphosphates
may be selected from the group consisting of tetrasodium pyrophosphate, sodium
tripolyphosphate, sodium tetraphosphate, sodium hexametaphosphate, and
mixtures thereof. The
amino phosphonic acid compounds may be selected from the group consisting of
amino
tri(methylene phosphonic acid), 1-hydroxyethylidene-l,1,-diphosphonic acid,
diethylenetriaminepenta (methylene phosphonic acid), ethylene diamine
tetra(methylene
phosphonic acid), and mixtures thereof. Furthermore, the amino-carboxylic acid
analogues may
be selected from the group consisting of ethylenediaminetetraacetic acid,
diethylenetrianzinepentaacetic acid, 2-hydroxyethyliminodiacetic acid,
nitrilotriacetic acid and
mixtures thereof.
The cleaning solution may further comprise at least one corrosion inhibitor
for inhibiting
corrosion of metallic substrates upon drying, in a concentration of from about
0.005% wlw to
about 5% w/w, or from about 0.005% wlw to about 1.5% w/w. The corrosion
inhibitor may be
selected from the group consisting of triazoles (e.g. 1,2,3-benzotri.azole),
nitrites (e.g. sodium
nitrite), molybdates (e.g. sodium molybdate), benzoates, gluconates, and C2 to
C5 polyhydric
alcohols (e.g. propylene glycol).
The at least one surfactant may be present in a concentration of from about
0.005% wlw
to about 4% w/w, or from about 1.5% w/w to about 4% w/w.
The at least one builder may be present in a concentration of from about 0.01%
w/w to
about 50% w/w, or from about 6% w1w to about 11% wlw, based on the total
weight of the
solution.
In some embodiments, for every one part by weight hydrogen peroxide in
solution, there
is from about 0.25 to about 4 parts by weight cation sequestering agent, Also,
certain
embodiments contain hydrogen peroxide in a concentration of from about 2.1 %
w/w to about
20% wlw, from about 2.1 % wlw to about 7% w/w, from about 2.1 % w/w to about
3% w1w, or
b
CA 02454437 2012-04-26
be about 2.1% w/w, at least. one cation sequestering agent in a concentration
of from about 0.5%
w/w to about 20% wlw, or from about 0.5% w/w to about 7% w/w, or from about
0.01 % w/w to
about 2% w/w, and at least one surfactant in a concentration of from about
0.005% w/w to about
3% w/w, or from about 0.01 % w/w to about 2% w/w, or from about 0.005% w/w to
about 3%
w/w.
The pH of the solution may be from about 9 to about 11.5 or from about 8 to
about 9.5.
Furthermore, the cleaning solution may comprise at least one buffer in all
amount effective to
buffer the solution to said alkaline pH.
In still other embodiments, the invention provides a low-foaming cleaning
solution
having a pH of from about 8 to about 9.5 and consisting essentially of.
a) at least one surfactant selected from the group consisting of sodium octyl
sulfonate,
sodium xylene sullfonate, and a block copolymer consisting of a
polyoxyethylene block capped at
both ends by polyoxypropylene blocks where the total molecular weight of the
polyoxypropylene
portion is 1700 and the polyoxyethylene portion comprises about 20% of the
total molecular
weight, and mixtures thereof, in a concentration range of from about 0.005%
wiw to about 4%
w/w;
b) hydrogen peroxide in a concentration of from about 2.1% w/w to about 3%
w/w;
c) at least one cation sequestering agent selected from the group consisting
of citric acid,
1 -hydroxyethylidene- 1, 1,-diphosphonic acid, and mixtures thereof, in a
concentration of from
about 0,001% w/w to about 11% w/w,
d) at least one corrosion inhibitor selected from the group consisting of
propylene glycol,
12,3-benzotriazole, sodium nitrite, sodium molybdate, propylene glycol, and
mixtures thereof,
in a concentration of from about 0.005% w/w to about 1.5% w/w; and
e) at least one solvent selected from the group consisting of water, deionized
water, and
mixtures thereof to 100% w/w.
In accordance with a second aspect, the invention provides a dry particulate
cleaning
formulation which can be dissolved in water, deionized water, or mixtures
thereof to form a
7
CA 02454437 2012-04-26
cleaning solution according to the first aspect. The dry particulate cleaning
formulation will
contain at least one source of hydrogen peroxide which may be selected from
the group
consisting of percarbonate (e.g. sodium percarbonate), persulphate, perborate
(e.g. sodium
perborate monohydrate and sodium perborate tetrahydrate), peroxyacids, dialkyl
peroxides,
diacyl peroxides, pre-formed percarboxylic acids, organic peroxides, inorganic
peroxides,
hydroperoxides, and mixtures thereof.
Furthermore, some embodiments may contain at least one source of hydrogen
peroxide in
an amount of from about 5% wlw to about 30% w/w, at least one builder in an
amount of from
about 5% w/w to about 50% w/w, and at least one surfactant in an amount of
from about 2% w/w
to about 20% w/w. The surfactant may be selected from the group consisting of
C3-C8 alkane
sulfonates and Cl to C4 alkylarenesulfonates,
Other embodiments of the dry particulate cleaning formulation may contain at
least one
source of hydrogen peroxide in an amount of from about 15% w/w to about 25%
w/w, at least
one builder in an amount of from about 1.0% w/w to about 20% w/w, and at least
one anionic
surfactant in an amount of from about 2% w/w to about 10% w/w.
The dry particulate cleaning formulation may further comprise at least one
inert filler
selected from the group consisting of sulfate salts, phosphate salts, and
carbonate salts,
In accordance with a third aspect, the invention provides a method of cleaning
equipment
used to circulate food products, in place, comprising:
(1) providing a cleaning solution according to the first aspect; and
(2) circulating said cleaning solution through equipment to be cleaned at a
temperature of
20 C or higher, or at a temperature of 40 C or higher.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
When the term "comprising" is used herein, it shall be construed to mean
"including but
not limited to." The term "consisting essentially of shall be construed to
mean "including the
listed components or ingredients and such additional components and
ingredients which do not
materially alter the basic and novel characteristics of the present cleaning
solution and particulate
8
CA 02454437 2012-04-26
formulation". For the sake of clarity, the basic and novel characteristics of
the present solution
and particulate formulation are the cleaning, stability and low-foaming
characteristics for a given
concentration of components or ingredients. For the sake of clarity, the term
"consisting
essentially of shall be construed to include the listed components or
ingredients, plus optional
buffers (e.g, caustic salts such as sodium hydroxide, potassium hydroxide, or
ammonium
hydroxide) to provide a cleaning solution having a pH value in the specified
ranges, inert fillers
and diluents (e.g. sulfate salts, phosphate salts, silicate salts, carbonate
salts, and mixtures
thereof), corrosion inhibitors to prevent corrosion of certain metal
substrates, and small or trace
amounts of other ingredients commonly or typically present in commercially
available
components or ingredients of the present inventive solution and particulate
formulation.
The term "builder" is used herein to refer to those ingredients in a cleaning
solution that,
through complexation, (i) eliminate alkaline-earth ions from water, substrate
or soils, and. (ii)
support detergent cleaning action by modifying the electrostatic properties of
soils, substrates
and wash liquor to enhance the detergency process, prevent soil redeposition,
facilitate surfactant
action, and influence solution foaming properties. Examples include
sequestering agents such as
sodium diphosphate; sodium tiphosphate, 1-hydroxyethane-l,l,-diphosphonic
acid,
diethyl.enetriaminepenta (methylene phosphonic acid), nitrilotrimethylene
phosphonic acid,
nitrilotriacetic acid, ethylenediaminetetraacetic acid, 2-
hydroxyethyliminodiaeetic acid, citric
acid and glycolic acid.
Without being limited by any theory herein, it is believed that several
mechanisms are
responsible for the cleaning performance of the solution, First, hydrogen
peroxide
9
CA 02454437 2003-12-30
oxidizes protein, carbohydrate and lipid molecules and destroys sulfhydryl and
double
bonds to break the molecules down into smaller units.
Second, builders, including cation sequestering agents (i.e. chelating
agents), are
believed to play an important role in the emulsification and break-up of soil
particles.
The builders are relied upon for enhancing detergency by (i) increasing the
negative zeta
potentials between soil aggregates and substrates, thereby creating an
electrostatic
repulsive force, and (ii) breaking down soil aggregates which are linked
together by
mutual cation bridges. Furthermore, chelating agents sequester dissolved
cations, thereby
minimizing the decomposition rate of the hydrogen peroxide in solution.
to Third, the alkaline conditions are believed to have the following effects.
The rate
of reaction of the hydrogen peroxide with organic soils is enhanced at the pH
levels of the
invention. These conditions contribute to the development of a greater zeta-
potential
difference between substrate and soil and amongst soil particles, thereby
facilitating
detachment of the soil from the substrate and its emulsification in solution.
Fatty acids
present in many of these soils undergo saponification, thus greatly enhancing
their
solubility and further providing additional detergent action to, or increasing
the surface
activity of, the solution as a whole. Reducing the interfacial tension of the
solution
through surfactants results in better wetting of the soil-substrate and soil-
soil interstices,
thereby facilitating detachment and break-up.
Furthermore, the surfactants employed should have a high hydrotroping
capacity,
should produce a reduction of the interfacial tension of the wash liquor, and
should not
produce substantial amounts of foam. Also, they should have cloud point
temperatures
above the temperature at which the solutions are used. The expression "cloud
point
temperature" means the temperature at which a surfactant begins to become
insoluble in
water and a cloudy dispersion results.
The invention will be better understood with reference to the following
examples:
Example I
A liquid solution IA of the present invention was prepared as shown in Table
I.
The ingredients were mixed in the order shown with hydrogen peroxide being the
final
CA 02454437 2003-12-30
ingredient added. The solution pH was adjusted with caustic potash (potassium
hydroxide) to a value of about 9.
TABLE I
.......... .....................................
..................................... .......................................
..............................
........................_.................................
_._..................... ..............................................
_................ .......
........................_............................. _....
_........................ -__....................
COMPONENT Solution IA Actual Concentration
(% actives) % w/w % w/w
.............. ........................ _..............
......................_........................ ....... _.............
..................................... ;...............................
................. .... _............. ................
.............................
............._...........................................................
............................................... _................
Deionized water q.s. to 100 to 100
................... ......... _.... _....... ............. ...................
_._......... ...... .............
.......................................................
........................................... ..... ......................
............ ..............................................
...........................................
_...........................................................................
Propylene Glycol (100%) 0.5 0.5
_._._...._..____._.....____._._._....._...._.__._._.
r_._._.__._____._....._.._ _.._.._.__.___.-.-..._____._._._...._.-.-
_.___._......._._._._ _._.__....._....._._...___._._._............... ........
___-_....... ___......... ;_._..-___....-............ __....
Bioterge PAS-8S (38%) 4.5 1.7
Briquest ADPA-60AW (60%) 7.0 4.2
___._...-.....__.__......... _.__._._._...._._.____....._.-.--.-.--__-
.._....._..__._.___....._........... _._.__._._._._.-.-----.._.... _..___..._--
---- -_...... _--------- __......... -._
Citric Acid (100%) 1.0 1.0
....
.......... ......................... ....................................
.................. .............................. ........ ..................
.............,............... _._.....................................
_................ ............._......... ................
...............................................................................
......... ............ ..... .................
Caustic Potash (45%) Adjust to pH of about 9 Adjust to pH of about 9
Hydrogen Peroxide (50%) 10.0 5.0
............................ ...._._................................
....................
...............................................................................
................. _.....-..............................
_._._..................... .... _................. ..........._..._ ......
............ ...................... ..... .........
........................_........................ ..........................
The solution IA of Table I includes hydrogen peroxide from a 50% aqueous
technical grade commercial solution from Degussa-HUls, Bioterge PAS-8S (trade-
mark)
which is a 38% active sodium octane sulfonate manufactured by Stepan, and two
builders
in the form of cation sequestering agents consisting of Briquest ADPA- 60AW
(trade-
mark) which is a 60% active 1-hydroxyethylidene-1,1,-diphosphonic acid
manufactured
by Allbright and Wilson, and citric acid. The solution also includes deionized
water as
the solvent and a short chain polyhydric alcohol consisting of propylene
glycol for
inhibiting corrosion of metal substrates upon drying of the solution.
The cleaning performance of the solution was evaluated by measuring the mass
of
soil removed from aged soiled panels carefully prepared in the laboratory.
Between 10 to
milligrams of dried milk was deposited on each 2" x 2" glass slide. A
plurality of the
15 soiled glass slides were immersed in the solution for a period of 5 minutes
without any
mechanical action. Experiments were run at two different solution
temperatures, 20 C
and 45 C. After immersion for the desired contact time, the slides were rinsed
with tap
water (200 ppm hardness as CaCO3) and allowed to dry for several minutes
before being
weighed. A cleaning efficiency was defined as:
C.E. = (M,-Mf) x 100/Mi
where M, is the initial mass of deposited soil, and Mfis the mass of soil
remaining after
immersion in the detergent for the specified time period. A commercial
detergent
11
CA 02454437 2003-12-30
solution (Example IB), commonly known by its trademark, Metriclean 2, sold by
Metrex
Research Corporation, and based on enzymes, was utilized for comparison. The
results
are included in Table I-1. Example IA was diluted in water of 200 ppm hardness
as
CaCO3 in the ratio 1:70, while the commercial enzymatic detergent solution IB
was used
in its recommended dilution rate of 1:140. It is clear that example IA offers
a
considerable improvement over the commercial detergent solution in dissolving
lipids and
proteins, particularly at an ambient temperature of 20 C.
TABLE I-1
................... ........ . .......................
......................... . .. . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . --- ......................
....................
Example IA Example 1B
20 C 45 C 20 C 45 C
o .... ...............
72 3
__....._.__._._....:
.................._.____._._._._..._.._-........ ....... ......
Exam lpeII
A more concentrated solution IIA summarized in Table II below may be made for
use at higher dilution ratios with the added benefit of the solution
exhibiting bactericidal
properties. Again, solution IIA was formed by mixing the listed ingredients in
the order
in which they appear in Table II.
TABLE II
............................. ...............
................................... .............. .................
................................._............................................
....... ......................................
..........................................
_.....,................................................... ...................
............................. _.........................
COMPONENT Solution IIA Actual Concentration
(% actives) % w/w % w/w
.............. _................... ...................
......................................... ............................
..................................... ......._6....... ............
....,...............................................................
Deionized water q.s. to 100 9.5 to 100
Bioterge PAS-8S (38%) 4.5
..
...............................................................................
...............................................................................
...............................................................................
.._............................................................................
..........................................................
Briquest ADPA-60AW (60%) 7.0
....... -_._.__........ _._..... ..... __.......... _..............
__._..__._._._.--_.._.._.__._._._.____._._._....._.
Citric Acid (100%) 1.0
..................... . ........................ _..... ..............
............ ........ _....... ................. ............................
.......... _....... ....... .-.........................
........................................ _................
.,..................... _......................
_..................................................
.......................................... .............
Caustic Potash (45%) Adjust to pH = 9 Adjust to pH = 9
......... ___-.-
..____._...___._.__._._._.___.____....._._.__._......_._.........
.._._........ Hydrogen Peroxide (50%) 14.0
...............................................................................
...............................................................................
...._;..................................,......................................
......._....................._..........................,......................
....................................................._.........................
................
Solution IIA was diluted in the ratio 1:140 and exhibited similar cleaning
efficiency values as compared to the values exhibited by a commercial
hypochlorite-
based cleaner IIB (at its recommended dilution of 1:512), as seen from the
experimental
results in Table 1I-1 below.
12
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TABLE II-1
Example IIA T Hypochlorite cleaner IIB
45 C 60 C 45 C 60 C
.................................._........................
_..................................
...............................,........................
........................... ..... ................. ....... .........
_.......... ................... . ......... _.... .....
_.............................
C. E. [%1 86 f 11 98 f 1 ! 76 10 7.1... .7
....................................... ............ ...........
.............................._.......
................................._....................
.......__._......._,..._........ _.......
....1._._._...._...........__._.._._.........._.___.....,...._.:.._.___......._
.._._....__.........._.___._..........._._...:
The higher temperatures in these experiments are more typical of applications
in
the food and dairy industry, where pipelines and storage tanks are cleaned and
sanitized
regularly with a detergent solution circulated throughout liquid carrying
pipes thereof at
elevated temperatures of above 20 C. Moreover, at the dilution ratio of 1:140,
solution
IIA is quite effective in reducing the viable counts of vegetative bacteria.
Reduction in
the viable counts of Staphylococcus aureus greater than 99.99% were observed
in a
suspension of organisms of 1.85 x 106 organisms per ml, at a contact time of 5
minutes,
and a temperature of 54 C.
Example III
Solutions IIIA, IIIB, and IIIC were prepared and summarized in Table III.
Solutions IIIA, IIIB, and IIIC were prepared by adding the listed components
or
ingredients directly to wash water (i.e. regular tap water having a 200 ppm/as
CaCo3
hardness). The pH of the solutions was the natural pH of the solutions. No
buffer was
added.
Solution IIIA is in accordance with the present invention. Solutions IIIB and
IIIC
are outside of the scope of the present invention and tested to show the
contribution of the
individual components, namely the hydrogen peroxide supplied by a source in
the form of
sodium percarbonate, and a cation sequestering agent in the form of sodium
tripolyphosphate. As can be seen in Table III, the hydrogen peroxide and
sodium
tripolyphosphate each possess cleaning properties. However, the combination of
hydrogen peroxide, sodium tripolyphosphate, and the specified anionic
surfactant (38%
w/w sodium octyl sulfonate) results in an unexpected and improved cleaning
performance.
13
CA 02454437 2003-12-30
o U
00
- o
C ` M - d 00
O O"
- o
H 3 O
061 0 0
00
a \ a~i
...................................s............_.........
..................... ...
...
O
~ ~ M \O M '"" d' ~O
O Oi O O
i~ O O ' O =--4 01
o vii
O O'`
r
oi b!
o yõ ~ , oo =.~ ' Rt
o Ep E'-' cn' o
O O O O , N
U ~ ~ v~ ~ A4 2r ~ U
CA 02454437 2003-12-30
As 0.33 gr of hydrogen peroxide is liberated per gram of sodium percarbonate,
solutions IIIA and IIIC contain hydrogen peroxide at a concentration of about
0.042%
w/w.
While solution IIIA was prepared by adding each component directly to the wash
water, in practice, a dry particulate formulation could be prepared containing
the above
components in dry form. This dry particulate formulation could then be
dissolved at the
appropriate dilution rate (e.g. 1 oz/4-6 gallons, or 10 mg/5-7.5 liters) to
obtain solution
IIIA.
Exam lb e IV
The foaming characteristics of solution IA, IIA, and IIIA in accordance with
the
invention were tested. They all exhibited an instantaneous foam height of less
than 6 ml
after 30 inversions on a stoppered standard 250 ml graduated cylinder. In the
tests, foam
dissipation occurred within a period of 5 seconds or less after termination of
the inversion
cycle. Thus, solutions according to the present invention were found to be low-
foaming.
Example V
All of the above solutions IA, IIA, and IIIA according to this invention were
subjected to accelerated stability testing as described by Steiner in US
5,736,497.
Samples of each solution were subjected to a temperature of 96 C for a period
of 16 hours
to simulate storage at 20 C for one year. In all cases, the peroxide loss was
less than
50%, which is generally accepted as good in this extreme temperature test.
Example VI
Solutions VIA and VIB according to the invention were formulated as shown in
Table VI below.
CA 02454437 2003-12-30
TABLE VI
..............
_........................................................_.....................
.............._...,..........................
Raw Material % w/w Solution Actual Solution Actual
VIA Concentration VIB Concentration
% w/w % w/w (VIA) % w/w % w/w (VIB)
DI water 62.35 62.35 49.66 49.66
.. ............... -............. .......... .... ..................
_......._................. .......... ............
._................................... ............._._................. .....
................. :......................... .............. ....... ..........
_................................. _..............................
..............
Pro ylene Gl col (10% 0.50 0.83 0.50 0.83
Briquest ADPA 60AW (60%)
1-hydroxyethylidene-
1,1,-diPhosPhonic acid 8.40 5.04 14.00 8.4
_........ ...............................
........._.
Citric acid (100%) 1.20 1.20 2.00 2.00
..... ............ . ........ .
Stepanate SXS (40%
sodium xylene sulfonate) _._ 7.98 3.19
---- - -.--.-.---_.-._.-..
-------------- .-._._.-._._ ___....-.-....._._.______.......... .__.-........
.... .... __._._-
Bioterge PAS-8S (45%
sodium octy1 sulfonate 2.00 0.90 6.00 2.70
.......... ...... ......... ................... ................._.......
_.... .............~............. ... __................ ...........
........... .............. ...................... .............
..._........................ .............. ............... ........ _....
..................... ....... ...........
...............................................................................
.
Pluronic 17R2 (PO-E0-PO
block copollnerZ(100%) 0.48 0.48 ._-- _._.___._.-_.-....-._.._?
Caustic Potash (45% KOH) 12.50 5.63 21.29 . 9.58
............. ............................... ....................
............ .......... ..............................-..............
................................................... .._......._. .......
_............. ,..................... ............
............................................. _.............................
Cobratec 35-G (35%
1,2,3-Benzotriazole + 65% 0.18 0.18
Propylene Benzotriazole Glycol) 0.50 1,2,3-Benzotriazole 0.50 1,2,3-
Benzotriazole
Sodium Nitrite (100%) 0.05 0.05 0.05 0.05
............ ............. . ..... .... ................... H2O2 ( 5 0 %
.......... ............... ....... ............................. 4.00.....
_'.............. 2.00 6.00 ........:.................................. ...
3.00...............
........._.
PH 9:2.._._._.9.2 9 ___._ 9 0
Avox loss 0.19 0.19 0.77 0.77
....................... ............. ................ ............
_._._......... ........... ........................................
................,_......-...............................................
.............. _._.._................. ......_.................
_._....................................... ............. _..........
...................................... ...............
..............................
The solutions were formulated by adding the listed ingredients in the order in
which they appear in the table. The pH of the solution was achieved by the
addition of
caustic potash at the above specified levels. Pluronic 1782 (trade-mark) is a
polyoxyethylene/polyoxypropylene block copolymers having a polyoxypropylene
molecular weight of from about 1700, of which 20% of the total molecular
weight is due
to the polyoxyethylene portion.
The storage stability of solutions of VIA and VIB according to the present
invention was evaluated by subjecting the solutions to an accelerated
stability test at 50 C
for a period of 24 hours as described by US 4,525,291 to Smith et al. That is,
a small
sample of each of the solutions was transferred to a clean plastic bottle
housed in a
constant temperature enclosure at 50 C. The available oxygen concentrations
(Avox) in
the solutions, measured before and after storage for a given period, was
determined by
testing small samples of the solutions using the standard acidified potassium
permanganate titration method. The stability of the solutions was evaluated by
assessing
the ability of the solutions to maintain their homogeneity and by measuring
the hydrogen
16
CA 02454437 2003-12-30
peroxide (or available oxygen (Avox)) loss. Solutions VIA and VIB showed
hydrogen
peroxide losses of less than 1% of the original content, and remained
homogeneous and
clear after the test period.
Solution VIA was tested to evaluate its bactericidal and virucidal activity
using
quantitative carrier test methods. The tests were run at 54 C and water with
200 ppm of
hardness was used for dilution.
TABLE VI-1 - The microbial activity of Solution VIA against Staphylococcus
aureus
.................... .................. ....................................
....................... ..._........................ ...........
...................... _._.................................................
.............. ...... ................ ..............
.................................. ....... .._................ ,........
_._.......... _.... ................. _.........................
Dilution Contact Time j CFU/Control Average CFU Loglo
(minutes) Carrier Test Carrier Reduction
............ ..........
1:50 ....... 7... 9.73 x106.. 14 6.16
..... ..... ...... ......... ..
Test method: QCT 1-ASTM E2111 (Standard Quantitative Carrier Test Method To
Evaluate the Bactericidal,
Fungicidal, Mycobactericidal and Sporicidal Potencies of Liquid Chemical
Germicides)
TABLE VI-2 - The microbial activity of Solution VIA against Poliovirus type 1
(Sabin)
Dilution Contact Time PFU/Control Average PFU { Loglo
(minutes) Carrier Test Carrier Reduction
1:50 5 1.61X103 0 3.21
............. __ ................ .._............ _._ _......... __-----------
_._ __._.-- _._.._._._._.__.__._........._._.... _.__._.... _..........
Test method: QCT II-ASTM E2197 (Standard Quantitative Disk Carrier Test Method
for Determining the
Bactericidal, Virucidal, Fungicidal, Mycobactericidal and Sporicidal
Activities of Liquid Chemical Germicides)
The results of Table VI-1 and Table VI-2 show Solution VIA to be an effective
bactericide and virucide.
Example VII
Solution VIB was tested on organic soils typically encountered in medical and
dental practices. Commercially available coupons sold in association with the
trademark
TOSI (sold by SteriTec Products Inc., Colorado, U.S.A.) were soiled with
standard
organic soils used for evaluating the efficiency of cleaners. The coupons
consisted of
stainless steel strips on which blood and fibrinogen-based soils were
deposited and dried.
The soiled coupons were then introduced in an ultrasound tank containing
solution VIB
diluted at the rate of 1:115, and afterwards inspected visually for any
remaining debris.
The coupons were completely clear after 3 minutes of processing in the tank at
a
temperature of 35 C, indicating satisfactory performance for the cleaning of
soiled
medical, dental and veterinary surgical instruments. No foam developed in the
ultrasonic
tank during the performance of the test.
17
CA 02454437 2012-04-26
Exam ple VIII
Another cleaning experiment was performed with solution VIA. Dental
instruments (two
dental scalpers, two dental spatulas and two hemostats) were soiled by
applying a solution having
10% wtw defibrinated sheep blood in deionized water, based on the total weight
of the sheep blood
solution. The solution was dried on the instruments for a period of 6 hours.
The instruments were
placed in a stainless steel basket and placed in a HydrimTM instrument
cleaning machine (sold by
SciCan, Toronto, Canada). Tests were run with solution VIA, no detergent, and
a highly alkaline (pH
12), phosphate-based commercial detergent sold in association with the
trademark Neodisher FT'TM
by Chemische Fabrik DR WEIGERT of Hamburg, Germany. The machine was programmed
to
dispense the cleaning solution at a dilution rate of 1:50, and the cleaning
cycle was effected at a
temperature of approximately 55 C for a period of 3 minutes. After the wash
cycle, the instruments
were individually brushed in phosphate-buffered saline with the purpose of
eluting the remains of
blood for detection using a HemastixN strip (sold by Beyer AG of Leverkusen,
Germany). This strip
can detect blood concentrations as low as I ppm. No blood was detected by the
HemastixTM strips
after one wash cycle with solution VIA, while all strips tested positive for
the presence of blood in
both the no detergent and Neodisher FTVM test runs.
The specific embodiments disclosed herein are by way of example only. The
invention as
disclosed above is also defined by the following claims.
18
