Note: Descriptions are shown in the official language in which they were submitted.
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IN THE UNITEI) STATES PATENT AND TRAI~EMARK OFFICE
TITLE: PHASE STABLE, THICKENED AQUEOUS ABRASIVE
BLEACHING CLEANSER
INVENTORS: KEVIN J. BRODBECK, ARAM GARABEDIAN, JR.,
BRIAN P. ARGO and AMY PENTICOFF
Related Applications: Thls is a continuation-in-part of Serial No. 08/125,949, ;
filed September 23, 1993, entitled "Thickened Aqueous Abrasive Cleanser with
10 lmproved Rinsability," the specification of which is incorporated herein by
reference thereto.
Field of the ~nvention -
lS The present invention relates to thickened aqueous abrasive
cleansers containing hypochlorite bleach with improved phase stability. ~ -
Background of the Invention
Thickened hypochlorite bleach solutions or compositions have -
long been used in a variety of applica~ions including hard surface cleaning,
20 disinfecting and the like. These compositions are typically provided with
increased viscosity for a number of reasons, principally to increase residence
time of the composition on non-horizontal surfaces.
Many different examples of thickened hypochlorite bleach
compositions have been available from a wide variety of sources for use in
25 hard surface cleaning. For example, ~inley et al., European Patent
Application EP 373,864 and Prince et al., U.S. Patent 5,130,043, disclosed ~ -
hypochlorite bleach compositions consisting of polyacrylate thickeners, an~ine
oxide detergent, and optional fa~ty acid soap and/or a bleach stable synthetic
anionic detergent for cleaning hard surfaces such as toilet bowls, bathroom
30 tiles and shower walls. However, both of these references do not disclose,
teach, or suggest the need to reduce or limit the free electrolyte, or ionic
strength, of thickened cleaners.
Other prior art references have also described various thickened
automatic dish washing liquid compositions using polyacrylates in combination
35 with colloidal thickeners to provide proper rheology and stability in
hypochlorite bleach compositions including various adjuncts. Stoddart, U.S.
Patent 4,576,728, and Corring, U.S. Patent 4,836,948, are representative of
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these other prior urt r~ferences. These types of cl~aners contain large
amounts of builders, or other materials, which would boost the ionic strength
of the resulting composition. Also, as automatic dish washing compositions
(or, "ADWD's"), such cleaners typically must include silicates as overglaze
5 protectors and contain relatively low amounts of surfactants, if at all, to
prevent high foaming action. ~ :
Additionally, there are examples of hypochlorite-containing
abrasive cleansers in the art, but they typically require either a colloidal clay -
thickener, such as disclosed in Hartman, U.S. Patents 3,985,668, 4,005,027 and ~ ;
4,051,056, a mLxture of surfactants, such as disclosed in Jones et al., U.S. - -~
Patent 4,352,678, or a stearate soap, such as disclosed in Chapman, U.S. Patent -
4,240,919. All of these systems suffer from disadvantages, such as premature
hardening in the colloidal clay-thickened systems, or poor phase stability, as in
the stearate-thickened systems.
Other examples of abrasive, hypochlorite-containing, thickened
liquid cleansers with good physical stability include Choy et al., U.S. Patents
4,599,186, 4,657,692 and 4,695,394, all of common assignment herewith.
A related application, Choy et al., U.S. Patent Application Serial
No. 08/125,949, filed September 23, 1993, entitled ~hickened Aqueous - -
Abrasive Cleanser With Improved Rinsability," commonly owned and assigned -- -
to The Clorox Company, discloses long-term phase and viscosity stable liquid -
abrasive cleansers, in which cross-linked polyacrylate, nonionic surfactant, pH
adjusting agent and calcium carbonate abrasive are combined. The disclosures ~ -
of that application are incorporated herein by reference thereto. ~ ~:
Generally, these compositions have performed satisfactorily for
their intended purpose. However, there is a need for thickened aqueous
abrasive cleansers containing hypochlorite bleach with improved phase and
bleach stability, offering improved characteristics and benefits.
Summary of the Invention
In one aspect of the invention, the invention provides a phase
stable, thickened aqueous abrasive cleanser comprising:
a) an effective amount of a cross-linked polyacrylate;
b) an effective amount of at least one bleach-stable surfactant; .
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c) an effective amounl nf a 1OW salt, hi~h purity hypochlorite;
d) an effective amount of a pH-adjusting agent;
e) an effective amount of particulate abrasive; and
f) the remainder as water.
S In another embodiment of the invention, the invention provides a - '
method of preparing a phase stable, thickened aqueous abrasive cleanser
comprising the steps of adding together~
a) water;
b) a low salt, high purity hypochlorite bleach; ~ ~
c) an abrasive; ~ :
d) at least one bleach-stable surfactant; and ;
e) a cross-linked polyacrylate, wherein, preferably, the
polyacrylate is added as the last step.
In another preferred embodiment of the invention, the cleanser
contains about 0.1-50~o calcium carbonate abrasive. The formulations having a
higher calcium carbonate content tend to have a plastic, creamy, flowable
rheology, while those of lower calcium carbonate content (0.1-25%) will tend
to have a shear-thinning rheology.
It is therefore an object of this invention to provide a -
hypochlorite bleach-containing thickened aqueous abrasive cleanser, without - ` -
significant syneresis. ~ ~ -
It is a further object of this invention to provide a hypochlorite
bleach-containing thickened aqueous abrasive cleanser which has improved
phase and viscosity stability. ~=`
It is a still further object of this invention to provide a
hypochlorite bleach-containing thickened aqueous abrasive cleanser which has ~ -
excellent chemical stability. ~-
It is another object of this invention to provide a hypochlorite
bleach-contain;ng thickened aqueous abrasive cleanser in which improved
thickening is achieved by coating the abrasive with a bleach-stable surfactant to - --
shield the abrasive from cross-linked polyacrylate thickener.
It is yet another object of this invention to provide a hypochlorite
bleach-containing thickened aqueous abrasive cleanser to improve the
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thickening of ~ polyac~late-thic~;ened rheology by the use of an amine oxide
surfactant.
It is still another object of this invention to provide a bleach-
containing thickened aqueous abrasive cleanser with a plastic rheology, which
provides improved flow characteristics relative to non-polymer thickened
cleansers, which frequently suffer from "bottle hangup," or a significant amountof residual product clinging to the container interior.
lt is also an object of this invention to provide an improved ~ -
method for preparing a bleach-containing thickened aqueous abrasive cleanser --
by adding a cross-linked polyacrylate thickener in the last step.
It is additionally an object of this invention to provide an
improved method for preparing a bleach-containing thickened aqueous -
abrasive cleanser which has a lower abrasive content in order to enhance the
cleanser's sheeting action on a vertical surface.
lt is furthermore an object of this invention to provide a bleach-
containing thickened aqueous abrasive cleanser which leaves no to minimal - Y
visible residue after rinsing from a surface.
It is additionally an object of this invention to provide a bleach~
containing thickened aqueous abrasive cleanser which has entrained air to -
impart enhanced thickening and phase stability. - : -
It is finally an object of this invention to provide a bleach-
containing thickened aqueous abrasive cleanser with a calcium carbonate as ~ -
the abrasive, at a content of about 0.1-25%, said cleanser having a shear-
thinning rheology. - -- Brief Description of the Drawings
Fig. 1 is a graphical depiction of the viscosity stability of one of
the preferred embodiments of this invention;
Fig. 2 is another graphical depiction of the viscosity stability of - `
one of the preferred embodiments of this invention; and --
Fig. 3 is yet another graphical depiction of the viscosity stabil;ty
of one of the preferred embodiments of this invention.
In each of the drawings, the viscosity, as measured in centipoise~ `
with each unit representing 1,000, is plotted on the y axis, while the time in
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213~06~
days is plotted ()n the x axis. Measurements at different temperatures are
represented by a box (21.1C), cross-hatch (37.7C) and a diamond (48.8C).
Detailed Description of the Prçfçr~çd Embodiments
The invention provides a hard surface, hypochlorite-containing,
abrasive scouring cleanser having no significant syneresis, undue viscosity or
yield stress value increase, stably suspends abrasives, and has excellent rinsing
characteristics. All of the foregoing advantages are present over time and afterthese compositions have been subjected to storage at elevated temperatures.
Furthermore, as compared to prior art cleaners which include
high levels of mixed surfactants, the present invention provides a stably
suspended abrasive scouring cleanser which uses relatively small amounts of
surfactants, thus lowering the total cost of producing these cleansers. The
absence of solvents results in a less irritating product as well.
In one embodiment, the invention provides a phase stable,
thickened aqueous abrasive cleanser comprising:
a) an effective amount of a cross-linked polyacrylate;
b) an effective amount of at least one bleach-stable surfactant;
c) an effective amount of a low salt, high purity hypochlorite; -
d) an effective amount of a pH-adjusting agent; -
e) an effective amount of abrasive; and
f) the remainder as water.
A further embodiment of the invention provides a method of -
preparing a phase stable, thickened aqueous abrasive cleanser comprising the
steps of adding together: ~ `
a)water;
b) a low salt, high purity hypochlorite bleach;
c) an abrasive;
d) at least one bleach-stable surfactant;
e) a cross-linked polyacrylate, preferably, as the last step. ` -~
The individual constituents of the inventive cleansers are
described more particularly below. As used herein, all percentages are weight
percentages of actives, unless otherwise specified. Additionally, the term
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"effective amount" me~ns an amount suf~lcient to accomplish the intended
purpose, e.g., thickening, suspending, cleaning, etc.
Polyacrylat~
The cross-linked polyacrylate polymers of the present invention -
are generally characterized as resins in the form of acrylic acid polymers.
These resins are well known for use in a number of applications and it is
commonly theorized that the carboxyl groups in the polymers are responsible -
for desirable characteristics resulting from the polymcrs.
Such cross-linked polyacrylate polymers are available from a
number of sources including materials available under the trade name
CARBOPOL~ from B. F. Goodrich Company and under the trade name
POLYGEL~ available from 3V Chemical Company. Cross-linked polyacrylate
polymers of a type contemplated by the present invention are also believed to
be available from other sources which are also contemplated for use within the
present invention and as defined herein.
The cross-linked polyacrylate polymers are generally
characterized as acrylic acid polymers which are non-linear and water-
dispersible while being cross-linked with an additional monomer or monomers
in order to exhibit a molecular weight in the range from eighty thousand to
about seven million g/mole, preferably about one hundred thousand to about -
seven million g/mole, more preferably about one million to seven rnillion ~-
g/mole. Additionally, an average forrnula weight for a polymer subunit is about - ~
60-120 g/mole, preferably 75-95 g/mole. The most preferred CARBOPOLs ~ -
average about 86 g/mole. Preferably, the polymers are cross-linked with a
polyalkenyl polyether, the cross-linking agents tending to interconnect linear -;
strands of the polyrners to form the resulting cross-linked product. The pH of
an aqueous polymer solution provides a rough measure of the number of
carboxyl groups in the polymer, and thus is an estimate of the degree of cross-
linking and/or degree of branching of the polymer. Preferably, the pH of a
2~o polymer solution at 21 C should be between 1.8 and 5.0, more preferably
2.0 and 3Ø The pH is measured before neutralization.
Generally all cross-linked polyacrylate polymers are effective for
achieving, in conjunction with the surfactant, the desired ~iscosity and stabili~
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;n compositions of the type contemplated by the present invention. However,
some differences particularly in terms of stability have been observed for
different cross-linked polyacrylate polymers. Suitable cross-linked polyacrylatepolymers for purposes of the present invention include the CARBOPOL 600
series, 900 series, 1300 series and 1fi00 series resins Most. preferred are the
CARBOPOL 1621 and 1610 resins (formerly known as 613 and 623 resins,
respectively), which include a cross-linking agent plus hydrophobe. Also
suitable is CARBOPOL 672 (formerly 614)~ More specific examples of
polymers selected from these series are included in the examples set fonh in
the ~xperimental Section below~ Similarly, effective cross-linked polyacrylate
polymers for purposes of the present invention also include those available
under the trade name POLYGEL and specified as DA, DB, and DK, available
from 3V Chemical Company, and the SOKOLAN~9 polymers produced by the
BASF Corporation.
As is also illustrated by the examples in the following ,~
Experimental Section, certain of the cross-linked polyacrylate polymers noted
above may provide particular advantages or features within a thickened
composition as contemplated by the present invention. Accordingly, it is also
contemplated by the present invention to particularly employ mixtures or
combinations of such polymers in order to produce compositions exhibiting
combined characteristics of the respective polymers.
Generally, the cross-linked polyacrylate polymers of the present
invention are believed to be tightly coiled in a presolvated condition with
relatively limited thickening capabilities. Upon being dispersed in water, tbe ; ``
polymer molecules are hydrated and uncoil or relax to varying degrees.
Thickening is particularly effective with the polyacrylate polymers when they
are uncoiled or relaxed as noted above. Uncoiling of the polyacrylate
polymers may be achieved for example by neutralizing or stabilizing the
polymer with inorganic bases such as sodium hydroxide, potassium hydroxide,
ammonium hydroxide or low molecular weight amines and alkanolamines.
Neutralization or stabilization of the polyacrylate polymers in this manner
rapidly results in almost instantaneous thickening of an aqueous solution
containing the polymers and surfactants. It is noted that the highest viscosity
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occurs when the polymer is completely neutralized; however, it has been
empirically determined that elasticity is greater when the polymer is only
partially neutralized. For some applications, it may be preferable to enhance
elasticity rather than viscosity, for example, to aid in dispensing through
restricted orifices, or to improve residence time on non-horizontal surfaces.
Elasticity is also important to suspend abrasives, although even when fully
neutralized the polymer retains sufficient elasticity for this purpose. - ;
As noted above, the particular effectiveness of the cross-linked
polyacrylate polymers in the present invention is believed to be due to a
characteristic yield point or yield value. In this regard, it is noted that a typical
liquid tends to deform as long as it is subjected to a tensile or shear stress of
the type created by dispensing the liquid from a spray-type dispenser or the
like. For such a liquid under shear, the rate of deformation or shear rate is
generally proportional to the shear stress. This relationship was originally setforth in Newton's Law and a liquid exhibiting such proportional or straight-linecharacteristics are commonly termed Newtonian liquids.
With respect to thickening, it should be noted that while there
are many types of inorganic and organic thickeners, not all will provide the
proper type of shear-thinning rheology desired in the invention. Common
clays, for instance, will likely lead to a false body rheology, which, at rest, turn
very viscous. A thixotropic rheology is also not desirable in this invention
since in the thixotropic state, a liquid at rest also thickens dramatically. If the
thixotrope has a yield stress value, as typically found in clay-thickened liquid ~ --
media, the fluid at rest may not re-achieve flowability without shaking or ~--
agitation. The surfactants included in the formulas of this invention are
important in achieving the shear-thinning rheology. The formulations of this
invention can develop viscosities in the range of 20-70,000 centipoise (cP),
preferably 1,000-40,000 cP, and most preferably 10,000-3Q000 cP. However, in
an alternative embodiment containing a lower amount of abrasives, a viscosity
of between about 4,000 to about 25,000, more preferably S,000 to 15,000, is
obtained.
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Bleach-Stable S~lrfactants
The most preferred bleach-stable surfactants are the amine
oxides, especially trialkyl amine oxides, as represented below.
R~
R-N-O
R"
Additionally, it may be suitable to use mono-short chain C14 alkyl, di-long
chain Cl0 2D alkyl amine oxides. In the structure above, R' and R" can be alkyl
of 1 to 3 carbon atoms, and arc most preferably methyl, and R is alkyl of
about 10 to 20 carbon atoms. When R' and R" are both methyl and R is alkyl
averaging about 12 carbon atoms, the structure for dimethyldodecylamine
oxide, a preferred amine oxide, is obtained. Other preferred amine oxides --
include the Cl4 alkyl (tetradecyl) and C16 (hexadecyl) amine oxides. It is
particularly preferred to use mixtures of any of the foregoing, especially a
mixture of Cl2 and C,6 dimethyl amine oxide. In general, it has been found
that the longer alkyl group results in improved viscosity development, better
stability, and reduced skin sensitivity, while the shorter alkyl group appears to
contribute to better cleaning performance. Representative examples of these ~ ~
particular type of bleach-stable nonionic surfactants include the ~ ;. '
dimethyldodecylamine oxides sold under the trademarks AMMONYX~ LO ' -
and CO by Stepan Chemical. Yet other preferred amine oxides are those sold
under the trademark BARLOX'D by Lonza, Conco XA sold by Continental
Chemical Company, AROMA~Cn' sold by Akzo, and SCHERCAMOXTY sold ~:
by Scher Brothers, Inc. These amine oxides preferably have main alkyl chain
groups averaging about 10 to 20 carbon atoms.
Betaines and their derivatives, especially Cl0~0 betaine$ may also
be useful in the compositions of the invention. Particularly preferred are
betaines such as those described in the previously mentioned Choy et al.
references, the disclosures of which are incorporated herein by reference.
The polyacrylates of the present invention are highly branched
and, as described previously, are relatively tightly coiled in a presolvated
condition. When dispersed in water, the polymer molecules are hydrated and
uncoil to some degree, providing some thickening. However, full viscosity
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development occurs only when the polymer is neutralized, creating a net
negative charge on the carboxyl group. Owing to the proximity of the carboxyl
groups, the negatives tend to repel each other, thus greatly increasing the
volume occupied by the polymer and resulting in significant thickening. ln any
system where cations may be present, however, these cations may mitigate the
electrostatic repulsion between adjacent anionic carboxyl groups or, in the caseof divalent cations, may actually bridge the carboxyl groups, thus recoiling thepolymer. Calcium is one such divalent cation which can create such a
problem. The use of such cross-linked polyacrylate thickeners in the art has
therefore been limited to compositions wherein high levels of calcium, for
example calcium carbonate, were not present. It has now been surprisingly
found that a polyacrylate can be used as a thickener even in a system
containing high levels of a calcium carbonate abrasive by employing the
identified surfactants. It is theorized that the surfactant affords viscosity ~ -
stability to the polyacrylate by "surfactant shielding," that is, the positive pole
of the surfactant is attracted to the negatively charged carboxyl groups of the
polymer, thus shielding the carboxyl groups from positively charged species. It
has been empirically determined that shielding-effective surfactants have a
hydrophobic - lipophobic balance (HLB) of between about 11-13. Most
preferred is an amine oxide. The surfactant is present in a shielding-effective ~ ~-
amount, generally about 0.1 to 10% by weight, more preferably about 0~ to
3% by weight. ~
Cosurfactants ~ ~`
A cosurfactant may be selected from anionic surfactants such as ~- I25 soaps (alkyl carboxylates), alkali metal alkyl sulfates, alkyl aryl sulfonates,
primary and secondary alkane sulfonates (SAS, also referred to as paraffin
sulfonates), alkyl diphenyl ether disulfonates, and mixtures thereof. ll~ese - ~`~
anionic surfactants will preferably have alkyl groups averaging about 8 to 20
carbon atoms. Most preferred are the soaps, especially potassium soaps. The
30 soaps utilized are typically formed in situ, by using the appropriate carboxylic
acid (e.g., a C6-18 carboxylic acid, such as, without limitation, lauric, stearic,
myristic acids, and unsaturated acids, such as coco fatty acid), and neutralizing
with e.g., potassium hydroxide (KOH). Other alkali metal hydroxides, such as
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sod;um hydroxides, can be utilized. Commercial sources of these fatty acids
include Henkel KGaA's Emery Division. Further, alkali metal salts of alkyl
aryl sulfonic acids might be useful, such as linear alkyl benzene sulfonates,
known as LAS's. Typical LAS's have C8 l6 alkyl groups, examples of which
S include Stepan Chemical Company's BIOSOFT~, and CALSOFT~
manufactured by Pilot Chemical Company. Still further potentially suitable
cosurfactants include the alkyl diphenyl ether disulfonates, such as those sold
by Dow Chemical Company under the name '~owfax," e.g., Dowfax 3B2.
Other potentially suitable anionic cosurfactants include alkali metal alkyl
sulfates such as Conco Sulfate WR, sold by Continental Chemical Company,
which has an alkyl group of about 16 carbon atoms; and secondary alkane
sulfonates such as HOSTAPUR SAS, manufactured by Farbwerke Hoechst
A.G., Frankfurt, Germany.
Determining an appropriate mixture of polyacrylate and
surfactants is very important to the invention. While theoretically anywhere
from about 0.01~o to 5~o polyacrylate can be used, and about 0.1 to 15%
surfactants, so long as proper rheology and lack of phase separation or
syneresis result, in practice it is preferred to use minimal quantities of `~ -
polyacrylate and surfactants. The amount that is ordinarily used is an amount
which is both abrasive-suspending and thickening-effective amount. Applicants
have found that preferably about 0.1% to 3%, and most preferably about 0.1%
to 1~o of polyacrylate, and preferably about 0.2S~b to S.0~o, most preferabb
about 0.5~o to 3.0~o of total surfactant are used in the cleansers of this
invention. These ranges appear to result in compositions having the desired
syneresis values, ability to suspend abrasives, enhanced rinsability and, because
of the reduced amount of actives in the compositions, lower overall
manufacturing costs.
Stabilizing A~ent
A stabilizing agent may be necessary to maintain viscosity and/or
phase stability when certain anionic cosurfactants are present. Preferred
stabilizing agents are hydrotropes, which are generally described as
non-micelle-forming substances, either liquid or solids, organic or inorganic,
capable of solubilizing insoluble compounds in a liquid medium~ As with
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surfactants, it appears that hydrotropes must interact or associate with both
hydrophobic and hydrophilic media. Unlike surfactants, typical hydrotropes do
not appear to readily form micelles in aqueous media on their own. In the
present invention, it is important that the hydrotrope act as a dispersant and
not as a surfactant. In this regard, it is commonly observed that a hydrotrope
is a dispersant which does not affect the critical micelle concentration ("CMC~
of the liquid system. As a dispersant, the hydrotrope acts to prevent micelle
formation by any anionic surfactants present. Similarly, it should be noted thatconcentration or amount of the material, as well as type, may also be critical
towards determining whether such material is a hydrotrope. Thus, materials
which ordinarily are classified surfactants may in fact behave as hydrotropes ifthe amount used is limited.
The preferred hydrotropes are alkali metal salts of benzoic acid
and its derivatives; alkyl sulfates and sulfonates with 6-10 carbons in the alkyl
chain, C8 14 dicarboxylic acids, anionic polymers such as polyacrylic acid and
their derivatives; and most preferably, unsubstituted and substituted, especially
the alkali metal salts of, alyl sulfonates; and unsubstituted and substituted aryl
carboxylates. As used herein, aryl includes benzene, napthalene, xylene,
toluene, cumene and similar aromatic nuclei. Further, "substituted" aryl means
that one or more substituents known to those skilled in the art, e.g., halo -
(chloro, bromo, iodo, fluoro), nitro, or Cl4 alkyl or alkoxy, can be present on
the aromatic ring. Other good dispersants include other derivatives of a~
sulfonates, salts of phthalic acid and its derivatives and certain phosphate
esters. Most preferred are alkyl naphthalene sulfonates (such as Petro 22
availahle from Petro Chemicals Company) and sodium xylene sulfonate (such
as Stepanate X, available from Stepan Chemical Company. Also preferred as
stabilizing agents are soaps, discussed above under cosurfactants. It is noted
here, though, that especially soluble alkali metal soaps of a fatty acid, such as
C6 14 fatty acid soaps, may perform a stabilizing function. Especially preferredare sodium and potassium soaps of lauric and myristic acid. When present,
sufficient stabilizing agent is added to stabilize, generally 0 to no more than
l~o by weight, preferably about 0.1 to 0.5 weight percent.
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pH Adj~l~tin~ ent
pH adjusting agents may be added to adjust the pH, and/or
buffers may act to maintain pH. In this instance, alkaline pH is favored for
purposes of both rheology and cleaning effectiveness. Additionally, if the
cleanser includes a hypochlorite source, a high pH is important for maintaining
hypochlorite stability. Examples of buffers include the alkali metal silicates,
metasilicates, polysilicates, carbonates, hydroxides, and mixtures of the same.
Control of pH may be necessary to maintain the stability of a halogen source
and to avoid protonating the amine oxide. For the latter purpose, the pH .,
should be maintained above the pKa of the amine oxide. Thus for the
hexadecyl dimethyl amine oxide, the pH should be above about 6. Where the
active halogen source is sodium hypochlorite, the pH is maintained above ~,
about pH IO.S, preferably above or about pH 12. Most preferred for this
purpose are the alkali metal hydroxides, especially potassium hydroxide. The
total amount of pH adjusting agent/buffer including that inherently present
with bleach plus any added, can vary from about 0.1% to 5%, preferably from
about 0.1-1.0%.
Hypochlorite Bleach
In this invention, it is important to use an alkali metal
hypochlorite bleach which has a relatively low salt content. .
In the invention, it has been found necessary to minimize or
avoid the presence of salts, such as sodium chloride, which contribute to ionic
strength within the compositions. The hypochlorite would thus preferably be
selected or formed in a manner to avoid the presence of such undesirable salts.
For example, hypochlorite bleaches are commonly formed by bubbling chlorine
gas through liquid sodium hydroxide or corresponding metal hydroxide to
result in formation of the corresponding hypochlorite. However, such reactions
commonly result in formation of a salt such as sodium chloride.
The present invention thus preferably uses hypochlorites formed
for example by reaction of hypochlorous acid with alkali metal hydroxide in
order to produce the corrèsponding hypochlorite with water as the only
substantial by-product. Hypochlorite bleach produced in this manner is
referred to as "high purity, high strength" bleach, or also, as ~ow salt, high
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purity" bleach, and is available from a number of sources, for example Olin
Corporation which produces hypochlorite bleach as a 30~o solution in water. -
The resulting solution is then diluted to produce the hypochlorite composition
of the present invention.
S The hypochlorite may be formed with other alkaline metals as
are well known to those skilled in the art. Although the term ~hypochlorite~
is employed herein, it is not intended to limit the invention only to thc use ofchloride compounds but is also intended to include other halides or halites, as
discussed in greater detail below. Generally, the present invention preferably
uses potassium hypochlorite and, somewhat less preferably, sodium
hypochlorite, produced by the high strength bleach process. To be avoided or
minimized is a hypochlorite of any alkali metal including a chloride salt of thecorresponding alkali metal. Here again, hypohalites formed v~ith similar
alkaline metals are similarly ~o be minimized. Furthermore, it is especially
desirable that the hypochlorite of the invention either avoids the inclusion of a
chloride salt as noted above or includes such a chloride salt only within a
range of up to about 5% by weight of the composition. As the hypochlorite -
component is increased from about 1% by weight of the composition, the ~ - ~
chloride salt should be even further reduced since the chloride salt, particularly - - :
in the presence of the hypochlorite component, makes it difficult to achieve
desirable thickening of the composition, or stability.
The hypochlorite and any salt present within the composition are
also the principal source of ionic strength for the composition. The ionic --
strength of the composition has an effect on thickening, that is, if the
percentage of salt as noted above is exceeded, it becomes difficult to achieve
desirable thickening in the composition. Moreover, high ionic strength may be
detrimental to the stability of the composition as it can cause collapse of the
polymer structure. In summary, the ionic strength of the compositions of the
present invention is maintained preferably less than about SM, more preferably
less than about 3M. It is to be noted, however, that control of ionic strength is
an additional avenue by which viscosity and rheology can be controlled, if
desired. In general, increasing ionic strength decreases viscosity, but also ~i`contributes to a more plastic, less shear-thinning rheology, and reduces
I....
213~06~
rinsability. The hypochlori~e is preferably present in an amount ranging from
about 0.1 weight percent to about 10 weight percent, more preferably about
0.2% to 5~;~c, and most preferably about 0.5% to 3%. p
Ahrasives
S Abrasives such as a perlite, silica sand may be used herein and
various other insoluble, inorganic particulate abrasives are also possible, suchas quartz, pumice, feldspar, tripoli and calcium phosphate. However, it is most ~;,
preferred to use calcium carbonate (also known as "calcite").
Calcium carbonate used in this invention appears to have a dual
role. On the one hand, it is an abrasive and thus is used in the invention to
promote cleaning action by providing a scouring action when the cleansers of
the invention are used on hard surfaces.
The abrasive can be present in amounts ranging from about .1%
to 70% by weight of the compositions of this invention, preferably about 20- -
50~ by weight. In an alternate embodiment, the abrasive -- preferably,
calcium carbonate -- content will be from about 0.5 to about 25~o, which
results in a more fluid product, which has the ability to sheet and cling onto
vertical surfa~es. Particle size will range from average particle size of about
ten to eight hundred, more preferably forty to six hundred, most preferably
fifty to five hundred microns. ln general, about 50% or more of the particles
will have particle diameters of greater than one hundred microns (pass through
U.S. 150 mesh sieves). Particle hardness of the abrasives can range from Mohs
hardness of about 2-8, more preferably 3-6. Calcium carbonate, also known as -
calcite, is available from numerous commercial sources such as Georgia -:
Marble Company, and has a Mohs hardness of about 3. Typically, a size of ~ `
U.S. 140 mesh is selected, although others may be appropriate.
Abrasives can affect the viscosity of the formulations. It is
known that there can be a "hard sphere" thickening phenomenon merely by the - ~ -
addition of insoluble materials into a liquid phase. In the systems of the --
invention, moreover, it appears that the abrasives help to thicken somewhat by
compressing the polyacrylate polymer.
However, when calcium carbonate is used as the abrasive, it has
an additional impact on thickening and suspension of actives in the
~; ~,,'' ~' ` ~ '
.'~: - . . .. .
~1340G~
16-
compositions herein. There appears to be an interaction between soluble
calcium -- which arises from having calcium carbonate in aqueous dispersion -
and the charged carboxylate groups of the cross-linked polyacrylate thickener.
The presence of CaC03 thus may mediate cross-linking of the polymer,
S resulting in co-thickening. This can be seen especially at room temperature,
for example, as depicted in the drawings, Figs. 1-3. Thus, it is preferable in
the production of these inventive cleansers to assure that the carbonate is
added prior to the a~dition of the surfactants, especially the amine oxide. And
it is additionally preferable to add the polyacrylate as the last step in the
manufacture. By following this order of addition, the reaction of free calcium
ions and the polyacrylate is essentially mitigated, apparently because the
calcium carbonate particles have become coagulated by the surfactants.
However, while it is preferred to add the polyacrylate as the last step, in fact,
an alternate order of addition can be beneficial. For example, when calcium
lS carbonate, or other porous abrasives, are added in the last step, theformulation becomes aerated, entraining air bubbles, thus resulting in
enhanced thickening and stability.
Water
It should be briefly noted that the main ingredient in the
inventive compositions is water, preferably water with minimal ionic strength.
Water provides the continuous liquid phase into which the other ingredients
are added to be dissolved/dispersed. This provides the unique nuid properties -of the invention. The amount of water present generally exceeds 30% and,
indeed, can be as high as 99Yo, although generally, it is present in a quantity
sufficient (q.s.) to provide the appropriate fluid characteristics desired of the
product.
Optional Tngredients
The composition of the present invention can be formulated to
include such components as fragrances, coloring agents, whiteners, solvents,
chelating agents and builders, which enhance performance, stability or
aesthetic appeal of the composition. From about .01% to about .5% of a
fragrance such as those commercially available from International Flavors and
Fragrance, Inc. may be included in any of the compositions of the first, second
~,.-. .
, . - . . .
. ~-
~' '
~13'10~
17-
or third embo~liments. Dyes and pigments may be included in small amounts.
Ultramarine Blue (UMB) and copper phthalocyanines are examples of widely ~;
used pigments which may be incorporated in the composition of the present
invention. Buffer materials, e.g. carbonates, silicates and polyacrylates also
S may be added, although there is the caveat that amounts of such buffers
should not be present so as to elevate the ionic strength of the compositions.
Additionally, certain less water soluble or dispersible organic
solvents, some of which are advantageously hypochlorite bleach stable, may be
included. These bleach stable solvents include those commonly used as
constituents for proprietary fragrance blends, such as terpene derivatives. The
terpene derivatives herein include terpene hydrocarbons with a functional
group. Effective terpenes with a functional group include, but are not limited
to, alcohols, ethers, esters, aldehydes and ketones. Representative examples
for each of the above classes of terpenes with functional groups include but arenot limited to the following: Terpene alcohols, includin~, for example,
verbenol, transpinocarveol, cis-2-pinanol, nopol, iso-borneol, carbeol, piperitol,
thymol, ~-terpineol, terpinen-4-ol, menthol, 1,8-terpin, dihydro-terpineol, nerol, ~
geraniol, linalool, citronellol, hydroxycitronellol, 3,7-dimethyl octanol, dihydro- -
myrcenol, ,s-terpineol, tetrahydro-alloocimenol and perillalcohol; Terpene - -
ethers and esters, including, for example, 1,8-cineole, 1,4-cineole, isobornyl
methylether, rose pyran, ~x-terpinyl methyl ether, menthofuran, tra~-anethole,
methyl chavicol, allocimene diepoxide, limonene mono-epoxide, iso-bornyl
acetate, nopyl acetate, ~-terpinyl acetate, linalyl acetate, geranyl acetate, ---
citronellyl acetate, dihydro-terpinyl acetate and neryl acetate; Terpene
aldehydes and ketones, including, for example, myrtenal, campholenic
aldehyde, perillaldehyde, citronellal, citral, hydroxy citronellal, camphor, ~
verbenone, carvenone, dihyro-carvone, carvone, piperitone, menthone, geranyl :
acetone, pseudo-ionone, ~-ionone,,s-ionone"so-pseudo-methyl ionone, normal-
pseudo-methyl ionone, Lso-methyl ionone and normal-methyl ionone.
Terpene hydrocarbons with functional groups which appear ~
suitable for use in the present invention are discussed in substantially greater ~ -
detail by Simonsen and Ross, The Terpenes, Volumes I-V, Cambridge ~ ~ -
University Press, 2nd Ed., 1947 (incorporated herein by reference thereto)~ -
~1~40G~
~1~
See also~ co-pen~ing and commonly assigned U.S. Patent Application Serial
No. 07/780,360, filed October 22, 1991, of Choy, incorporated herein by
reference thereto.
Methods of Pre~arin~
In one method for preparing the compositions of this invention, - -
all of the ingredients are charged into an apprbpriate volume vessel and mixed.
However, because large scale processing is sometimes facilitated by addition
order, numerous methods of preparation were explored and tested herein.
There is another preferred addition order used to develop the
desired viscosity and to enable the polyacrylate system to maintain the viscosity
over time. In this preferred process water, pH adjusting agent, low ionic
strength, high purity hypochlorite bleach, preferably, potassium hypochlorite,
are added, along with the abrasive, typically, calcium carbonate are mixed in a
suitable vessel, with stirring, and allowed to degas. Next, surfactants, such aslS the bleach-stable nonionic surfactant, and, if used, an anionic surfactant, are
added. The polyacrylate is then added as an aqueous dispersion. Further
thickening is observed. Adjuncts such as fragrances may be emulsified by the
surfactant(s) and can be added either prior to, or after, polymer addition. -~ ~
Finally, mixing speed and duration may be adjusted as necessary to incorporate ~ ~ -
any adjuncts.
In yet another preferred process, all ingredients except for the
abrasive, preferably, calcium carbonate, are combined. This will generally ~-
result in a gel, such as described in Garabedian et al. (U.S. Patent Application ~:
Serial No. 08/097,738, filed July 27, 1993, of common assignment herewith,
and incorporated herein by reference thereto). Thereafter, the abrasive is -x~
charged directly into the gel and dispersed with good mixing. The gel breaks -~
down, forming a somewhat lumpy dispersion, at first, then gradually resulting ~- .
in an opaque, creamy, thickened liquid, wherein the abrasives are well - ~-`
suspended. Beneficially, since good mixing was used, aeration of the product
occurs, resulting in entrained air bubbles, causing somewhat higher viscosity. -
This somewhat higher viscosity (above 25,000 cp) may have performance
benefits for cleaning applications requiring a stiffer formulation. -
..;- . ~
.
.. ~ .. . .
~ .
" --,
~13~06~
-19-
The Experimental section below depicts various examples of the
formulations of the invention, as well as empirical observations on their
advantages.
Experimental - , ;
S In Example 1, a preferred formulation is set forth.
Example I
In~redient Wt. %Actives Wt.%
Preblend
KOCI (16.8%) 7.47 1.25
H2O (50% oftotal) 13.00 12.66
CaCO3 30.00 29 22
50.4; 33.13
Formul~on
H20 (50Yo of total) 13.00 12.66 -
KOH (45% sol.) 1.72 .18 ~ -:
Amine Oxidel (30~) 1.24 37 -
Soap Solution2 (8.75%) 5.6 .49 - -
Preblend (from above) 50.47 33.13 ~ .
Cross-linked polyacrylate328.00 30 " - -~
- ~ - . .
Fragrance Oil 0.04 04 ~ -~
. .. ..
3S Remaining H2O q.s.
100.00% -
I Barlox 12, from Lonza Chemical.
2 CoCO fatty acid soap.
3 Carbopol 1610, from B.F. Goodrich.
.1 .'
1.. : ,
".... . - ~ .
~13~06~
-20-
In this E ;ample 1, the first four ingredients were added, resulting
in a thin liquid. The po~assium hypochlorite/calcium carbonate preblend was
then added, with good mixing. Finally, the polyacrylate and the fragrance oil
were added, resulting in good, controllable thickening. (It should again be
S noted that the fragrance oil can, optionally, be added with the surfactants.)
The resulting product had a thick and creamy consistency. Using a Brookficld
RVT Rotoviscometer, loaded with a #4 spindle, at 5 rpm, after 5 minutes of
mixing, at 24.9C, the resulting viscosity was 23,960 cp.
This Example I had excellent viscosity stability. The Table 1
10 be~ow demonstrates the stability at room and elevated temperatures, and over
an extended period.
Table I
Time Temperat~!re Viscosity
Time 0 21.1C 24,800 cp
48.8C 24,800 cp
Time = 7 days 21.1C 25,720 cp
48.8C 31,320 cp
In the next Example 11, a further preferred forrnulation was --
prepared.
,, ; '
.
.
~13~0~
Ex;~mpl~ ~!
lngredient Wt. ~c AcIives Wt.~o
D.l. H2O 24.77 q.s.
KOH 1.22 0.55
KOCI 7.60 0.125
CaC03 35.00 35.00
Amine oxidel 3.00 0.90
Soap Solution~ 5.60 0.49
Polyacrylate Dispersion3 22.77 0.37 -~
Fragrance Oil 0.04 0.04 - 3
~~~~~~~~
100.005~ ' ' "' '
~ Barlox 1216, from Lonza Chemicals. In the Examples following, unless
otherwise noted, the identification of the ingredients in these footnotes is the2S same.
2 Lauryl soap solution, 8.75~rO actives, formed by neutralizing lauric acid in situ
with KOH.
3 Carbopol 1610, from B.F. Goodrich. -`` - --
This Example 11 also had excellent viscosity stability. The Table
2 below demonstrates the stability at room and elevated temperatures, and --
over extended time periods. - -
Table 2
Time Temperature Viscosity
Time 0 21.1C 19,600 cp ~ `
Time = 7 days 21.1C 21,120 cp : ~ ~
37.7C 21,240 cp
48.8C 2Q880 cp
Time=12 days 21.1C 21,440 cp
37.7C 20,440 cp
48.8C 2Q560 cp -~
~. .: - . . .
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,
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!:, ~, . ~ . ' ,
213~06~
In the next E.Yample 111, a further preferred formulation was
prepared. Example !ll
Ingredien~ Wt. % Actives Wt.~o
s
D.l. H,O 23.85 q.s.
KOH 1.25 0.55
KOCI 7.60 0.125
CaCO3 35.00 3S.00
Amine oxide 3.00 0-90
.'
Soap Solution 5.60 0.49
Polyacrylate Dispersion 23.69 0.385
Fragrance Oil 0.04 0.04 ~
100.00% .~ :"
.. .
- ~,':-.
This Example III additionally had excellent viscosity and ;-
syneresis stability, except for at the highest temperature over extended time.
The Table 3 below demonstrates the viscosity stability at room and elevated -~
temperatures, and over extended time periods. This is also graphically
depicted in Fig. 1 of the Drawings. Table 4 demonstrates syneresis stability.
(Syneresis was determined by metering the liquid formulations into clear, 16 ~--
fluid oz. bottles and measuring the height of the watery layer over the opaque, - ~ ~~
creamy liquid layer.) - ~ `
Table 3 - .
Viscosity ~~
Time Temperature ViscositY -
Time 0 21.1C 19,6000 cp - `
37.7C 19~6000 cp
48.8C 19,6000 cp
Time=5 days 21.1C 21,160 cp
37.7C 2Q000 cp
48.8C 20~920 cp
. ~ ,. ,
.
.
2134062
-23-
Time = 11 days 21.1C22,240 cp
37.7C21,360 cp
48.8C17,000 cp
Time = 18 days 21.1C20,720 cp
37.7C22,840 cp
48.8C520 cp
Table 4 -
Syneresis - - -
Time Temperature
21.1 C 37.7 C 48.8 C
O 0% 0% 0% , ~
5 days 0% 0% % ~ - -
'.
11 days 0% 3% 3% -
18 days 0% 3% 30%
In the next Example IV, a still further preferred formulation was - ~ -
prepared.
.. .. ....
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:.
'~
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...,~ .- ~.
, , ` ' ` `
~3406~ ~
24-
~x;lm~le IV
- .
b Ingrçsliçnt Wt. ~0 Actives Wt.~o
D.I. H~O 23.85 q.s.
KOH 1.25 0.55
KOCI 7.60 0.125 ., .
t 10 ~,
CaCO3 35.00 35.00
Amine oxide 3.00 0.90
Soap Solution5.60 0.49
Polyacrylate Dispersion 25.00 0.40 -
Fragrance Oil0.04 0.04
~~~~~
100.00%
, .....
This Example IV additionally had excellent viscosity and ~ ;"t'~
syneresis stability, even at the highest temperature over extended time. The -:
25 Table 5 below demonstrates the viscosity stability at room and elevated
temperatures, and over extended time periods. This is also graphically
depicted in Fig. 2 of the Drawings. Table 6 demonstrates syneresis stability. ~ "-Z
- ,. ~
. .. .
Table 5 . .-~
Viscosity --`
Time Temperature yj~
Time 0 21.1C 20,000 cp
37.7C 20,000 cp
48.8C 20,000 cp
Time=4 days 21.1C 22,240 cp
37.7C 21,080 cp
48.8C 18,400 cp
Time=12 days 21.1C 24,680 cp
37.7C 20,520 cp
48.8C 15,580 cp
. ~
~......
~"`''''~:,-' ` ' '
213406~
-2S-
.-..... .... .... .
Syneresis -
Time Temperature -
21.1C 37.7C 48.8C .. :;
O 0% 0% % " ,~
~' "~"''~''
4 days 0% 0% % - ~ -
12 days 0% 0% 3%
15In the next Example V, a still further preferred formulation was ~ -
prepared. As can be seen from the preceding examples II-IV, the amount of - ~.
cross-linked polyacrylate is increased, resulting in increasing longterm viscosity
and syneresis stability. .-
Example V ~ - ;
Ingredient Wt. %Actives Wt.% .~ ~ -
D.l. H2O 23.85 q.s. . ~
.-.~
KOH 1.25 0.S5
KOCl 7.60 0.125
CaCO3 35.00 3S.00
Amine oxide 3.00 0.90
Soap Solution 5.60 0.49
Polyacrylate Dispersion26.25 0.42
Fragrance Oil 0.04 0-04
. . . .
100 00% ' "' ' ~ '`'
This Example V additionally had excellent viscos;ty and syneresis
stability, even at the highest temperature over extended time. The Tablc 7
below demonstrates the viscosity stability at room and elevated temperatures,
. ..
- ~ -
t; ~
r~
. ~.~.. " , : , , .
213~nG~
-~6-
and over extencled time periods. This is also depicted graphically in Fig. 3 of
the Drawings. Table 8 demonstrates syneresis stability.
Tahle 7 : ~- -
Visco~ity
Time TemperatureViscosity ~ -
Time 0 21.1C 20,280 cp ~-
37.7C 20,280 cp - - -
48.8C 20,280 cp -
Time=4 days 21.1C 24,520 cp
37.7C 23,400 cp
48.8C 19,000 cp
Time=12 days 21.1C 26,560 cp -
37.7C 23,880 cp -~
48.8C 17,680 cp - ~
~ ~`` ` ~'.`
Table 8
Syneresis
Time Tçm~erature - -
21.1C 37.7C 48.8C -- ~ -
O 0% 0% 0%
4 days 0% 0% 0%
12 days0% 0% 3%
, .
In the next Example Vl, a further embodiment of the invention
is portrayed. In certain types of bathroom cleaners, it appears preferable to -
have a somewhat more flowable, or shear-thinning rheology, especially since
these types of cleaners are intended to be applied to vertical, or curved
surfaces, such as toilet bowls. While it is not quite certain whether these more :
flowable rheologies are actually shear-thinning (in fact, it is possible that these
types of cleaners may merely have a longer relaxation time), the cleaner of
Example VI has, in contrast to the preceding examples, a lower calcium
~ ~'`' " ' ' ' '
-
: -
~ :~
~ . '
~13~06~ `
-~7- -
carbonate content, ~nd a higher cross-linked polyacrylate content. The
resulting cleaner has, again, excellent viscosity and syneresis stability.
Example Vl
S lngre~l~~ Wt. C~C Actives Wt,~
D.l. H2O 43.84 86.43
KOH (4S~o) 1.72 0.77
KOCI (16.5%) 7.S0 0.124 ~ -
CaCO3 10.00 10.00
Amine oxide' 1.24 0.37
Soap Solution' 5.60 0.49
Polyacrylate Dispersion3 30.00 0.60
Fragrance Oil 0.1 0.1
100.00%
~ .. ;
~5
~ Ammonyx LO/CO (30~o active), from Stepan Chemical. ~ ~-
2 CoCO fatty acid solution (8.75~o active), neutralized with KOH.
3 Carbopol 1610 solution (2~o active). -~
This Example VI also had excellent viscosity and syneresis
stability, even at the highest temperature over extended time. The Table 9
below demonstrates the viscosity stability at room and elevated temperatures, `-
and over extended time periods. Table 10 demonstrates syneresis stability.
,~
;. -,, .
~,i ~,;
,,.-..
~-' ''.~'~-
, . . .
~1340B~
~x~
. ....
Tahle 9 --
Viscosity ., '~' '., .'-
Time Temperat~Le Viscosity :~
1 week 21.1C 10,400 cp
37.7C 11,000 cp
48.8C 10,000 cp
. ' -: ' '
2 weeks 21.1C 10,300 cp . .'
37.7C 11,800 cp - 5'''i~;~
48.8C 10,400 cp j ,
3 weeks 21.1C lQ400 cp :.- . . rY
37.7C 11,600 cp .... - ^:
48.8C 10,300 cp . .
4 weeks 21.1C N/A
37.7C 11,200 cp
48.8C 6,200 cp - .
.Table 10 . -
Syneresis . ::
Time Temperature
21.1C 37.7C 48.8C
.~
1 week trace slight trace N/A ~ ~
2 weeks 2.25% -1% 1.4% . - . ~.
3 weeks 2.7% 2.0% 2.0% .
4 weeks 4.2~o 2.0% N/A ..
The above examples have been depicted solely for purposes of
exemplification and are not intended to restrict the scope or embodiments of ~ .
the invention. The invention is further illustrated with reference to the claimswhich follow hereto.
~:.~, '.
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