Note: Descriptions are shown in the official language in which they were submitted.
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LIGHT-DUTY LIQUID OR GEL DISHWASHING
DETERGENT COMPOSITIONS HAVING CONTROLLED Ph AND
DESIRABLE FOOD SOIL REMOVAL AND SUDSING
CHARACTERISTICS
TECHNICAL FIELD
The present invention relates to liquid or gel dishwashing detergent
compositions suitable for use in manual dishwashing operations. These
compositions contain detergent surfactants, suds boosters, pH control agents
and
other adjuvants which in combination serve to impart consumer preferred food
soil
cleaning and sudsing characteristics to such dishwashing detergent products.
I S BACKGROUND OF THE INVENTION
Light-duty liquid (LDL) or gel detergent compositions useful for manual
dishwashing are well known in the art. Such products are generally formulated
to
provide a number of widely diverse performance and aesthetics properties and
characteristics. First and foremost, liquid or gel dishwashing products must
be
formulated with types and amounts of surfactants and other cleaning adjuvants
that
will provide acceptable solubilization and removal of food soils, especially
greasy
soils, from dishware being cleaned with, or in aqueous solutions formed from,
such
products.
Heavily soiled dishware can present special problems during manual
dishwashing operations. Articles such as plates, utensils, pots, pans,
crockery and
the like may be heavily soiled in the sense that relatively large amounts of
food soils
and residues may still be found on the dishware at the time such soiled
dishware is to
be manually washed. Dishware may also be heavily soiled in the sense that food
soil
residues are especially tenaciously adhered or stuck to the surfaces of the
dishware
to be cleaned. This can result from the type of food soils present or from the
nature
of the dishware surfaces involved. Tenacious food soil residues may also
result
from the type of cooking operations to which the soiled dishware had been
subj ected.
When heavily soiled dishware is to be manually cleaned, very often highly
concentrated, or high concentrations of, dishwashing detergent products are
used.
Frequently, this will involve direct application to the soiled dishware of a
liquid or
gel product in its undiluted or neat form. During such applications, the pH
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characteristics of the dishwashing composition can have a significant effect
on the
ability of the composition to solubilize and remove food soils such as greasy
soils.
Product pH furthermore can determine the effectiveness of conventional aqueous
dishwashing solutions in removing greasy soils from dishware. In general,
aqueous
dishwashing solutions that are more alkaline in nature are more effective at
removing such soils.
In addition to being useful for cleaning dishware, LDL or gel compositions
will also desirably possess other attributes that enhance the aesthetics or
consumer
perception of the effectiveness of the manual dishwashing operation. Thus,
useful
hand dishwashing liquids or gels should also employ materials that enhance the
sudsing characteristics of the wash solutions formed from such products.
Sudsing
performance entails both the production of a suitable amount of suds in the
wash
water initially, as well as the formation of suds which last well into the
dishwashing
process.
I 5 Given the foregoing, there is a continuing need to formulate manual
dishwashing liquids and gels that provide an acceptable and desirable balance
between cleaning performance, in both concentrated direct application and
aqueous
washing solution contexts, and product aesthetics. Accordingly, it is an
object of the
present invention to provide light-duty liquid or gel dishwashing compositions
which are especially effective at removing food soils from dirty dishware when
such
compositions are used in the context of a manual dishwashing operation.
It is a further object of this invention to provide such compositions having
desirable pH characteristics for use in either a direct application to
dishware context
or in an aqueous dishwashing solution context.
It is a further object of the present invention to realize such compositions
that
provide suitable and desirable sudsing performance.
It has been found that certain selected combinations of surfactants, suds
boosters, pH control agents and other adjuvants can be made to provide
dishwashing
compositions that achieve the foregoing objectives. The elements of these
selected
combinations of ingredients are described as follows:
SUMMARY OF THE INVENTION
The present invention relates to controlled pH, aqueous light-duty liquid or
gel detergent compositions having especially desirable soil removal and
sudsing
performance when such compositions are used to clean heavily soiled dishware.
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Such compositions comprise A) from about 20% to 40% of a specific type of a
anionic surfactant component; B) from about 3% to 10% of a certain type of
nonionic surfactant component; C) from about 2% to 6% of a suds
booster/stabilizer;
' D) from about 50% to 75% of an aqueous liquid carrier; and E) from about
0.2% to
6% of a pH control agent, such as sodium carbonate, which is effective for
' maintaining pH of a 10% aqueous solution of the composition within the range
of
from about 9 to 11.
The anionic surfactant component essentially comprises alkyl ether sulfates
containing from about 8 to 18 carbon atoms in the alkyl group. These alkyl
ether
sulfates also contain from about 1 to 6 moles of ethylene oxide per molecule.
The nonionic surfactant component essentially comprises Cg_Ig
polyhydroxy fatty acids amides. In the nonionic surfactant components such
polyhydroxy fatty acids amides may also be combined with from about 0.2 % to
2%
of the composition of a nonionic co-surfactant. This nonionic co-surfactant is
selected from Cg_lg alcohol ethoxylates having from about 1 to 15 moles of
ethylene oxide, ethylene oxide-propylene oxide block co-polymer surfactants
and
combinations of these nonionic co-surfactants.
The suds booster/stabilizer utilized in the compositions herein are selected
from betaine surfactants, hydroxy-free fatty acid amides, amine oxide
semipolar
nonionic surfactants and Cg_22 alkylpolyglycosides. Combinations of these suds
booster/stabilizers may also be utilized.
The foregoing essential components, as well a number of additional optional
ingredients, can be combined in conventional manner to form the light-duty
liquid or
gel dishwashing detergent products of this invention. One type of ingredient
which
has typically been employed in dishwashing detergent products, but which
should
not be utilized in the relatively high pH compositions of this invention,
comprises
any source of calcium or magnesium ions.
DETAILED DESCRIPTION OF THE INVENTION
The light-duty liquid or gel dishwashing detergent compositions of the
present invention contain five essential components. These components are:
{ 1 ) a certain type of anionic surfactant;
(2) certain nonionic surfactants;
(3) certain suds boosters/stablizers;
(4) an aqueous liquid carrier; and
(5) a pH control agent .
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A wide variety of optional ingredients can also be added to compliment the
performance, rheological and/or aesthetics characteristics of the compositions
herein.
The essential and optional components of the instant light duty liquid or gel
dishwashing detergents are described in detail as follows, along with
composition
preparation and use. In describing the compositions of the present invention,
it
should be noted that the term "light-duty dishwashing detergent composition"
as
used herein refers to those compositions which are employed in manual (i.e.
hand)
dishwashing. Such compositions are generally high sudsing or foaming in
nature.
In describing the compositions of this invention, it should also be noted that
all
concentrations and ratios are on a weight basis unless otherwise specified.
Anionic Surfactant Component
The compositions herein essentially contain from about 20% to 40% of an
anionic surfactant component. More preferably the anionic surfactant component
comprises from about 25% to 35% of the compositions herein.
The anionic surfactant component essentially comprises alkyl ether sulfates.
Alkyl ether sulfates are also known as alkyl polyethoxylate sulfates. These
ethoxylated alkyl sulfates are those which correspond to the formula:
R'-O-(C2H40)nS03M
wherein R' is a Cg-C 1 g alkyl group, n is from about 1 to 6, and M is a salt-
forming
cation. Preferably, R' is C10-16 alkyl, n is from about I to 4, and M is
sodium,
potassium, ammonium, aikylammonium, or alkanolammonium. Most preferably, R'
is C 12-C 16, n is from about 1 to 3 and M is sodium. The alkyl ether sulfates
will
generally be used in the form of mixtures comprising varying R' chain lengths
and
varying degrees of ethoxylation. Frequently such mixtures will inevitably also
contain some unethoxylated alkyl sulfate materials, i.e., surfactants of the
above
ethoxylated alkyl sulfate formula wherein n=0.
Nonionic Surfactants
The compositions herein also essentially contain from about 3% to 10% of a
certain type of nonionic surfactant component. More preferably, the nonionic
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surfactant component will comprise from about 4% to 6% of the compositions
herein.
One essential type of nonionic surfactant which is present in the
compositions herein comprises the Cg_Ig polyhydroxy fatty acid amides. These
5 materials are more fully described in Pan/Gosselink; U.S Patent 5,332,528;
Issued
Juiy 26, 1994, which are incorporated herein by reference. These polyhydroxy
fatty
acid amides have a general structure of the formula:
O Rl
R2-C-N-Z
wherein R 1 is H, C 1-C4 hydrocarbyl, 2-hydroxyethyl, 2-hydroxypropyl, or a
mixture thereof; R2 is Cg-CI8 hydrocarbyl; and Z is a polyhydroxylhydrocarbyl
having a linear hydrocarbyl chain with at least 3 hydroxyls directly connected
to the
chain, or an alkoxylated derivative thereof. Examples of such surfactants
include the
C l 0-C I g N-methyl, or N-hydroxypropyl, glucamides. The N-propyl through N-
hexyl C 12-C I 6 glucamides can be used for lower sudsing performance.
Polyhydroxy fatty acid amides will preferably comprise from about 3% to 5% of
the
compositions herein.
In the nonionic surfactant component of the compositions herein, the
polyhydroxy fatty acid amides hereinbefore described may be combined with
certain
other types of nonionic co-surfactants. These other types include ethoxylated
alcohols and ethylene oxide-propylene oxide block co-polymer surfactants, as
well
as combinations of these nonionic co-surfactant types.
Ethoxylated alcohol surfactant materials useful in the nonionic surfactant
component herein are those which correspond to the general formula:
R1-O-(C2H40)nS03M
wherein RI is a Cg-C I g alkyl group and n ranges from about 1 to 15.
Preferably R 1
is an alkyl group, which may be primary or secondary, that contains from about
9 to
15 carbon atoms, more preferably from about 10 to 14 carbon atoms. Preferably
the
ethoxylated fatty alcohols will contain from about 2 to 12 ethylene oxide
moieties
per molecule, more preferably from about 8 to 12 ethylene oxide moieties per
molecule. The ethoxylated fatty alcohol nonionic co-surfactant will frequently
have
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a hydrophilic-lipophilic balance (HLB) which ranges from about 6 to 15, most
preferably from about 10 to 15.
Examples of fatty alcohol ethoxylates useful as the nonionic co-surfactant
component of the compositions herein will include those which are made from
S alcohols of 12 to 15 carbon atoms and which contain about 7 moles of
ethylene
oxide. Such materials have been commercially marketed under the tradenames
Neodol 25-7 and Neodol 23-6.5 by Shell Chemical Company. Other useful Neodols
include Neodol 1-5, ethoxylated fatty alcohol averaging 11 carbon atoms in its
alkyl
chain with about 5 moles of ethylene oxide; Neodol 23-9, an ethoxylated
primary
C 12-C 13 alcohol having about 9 moles of ethylene oxide and Neodol 91-10, an
ethoxylated Cg-C 11 primary alcohol having about 10 moles of ethylene oxide.
Alcohol ethoxylates of this type have also been marketed by Shell Chemical
Company under the Dobanol tradename. Dobanol 91-5 is an ethoxylated Cg-C 11
fatty alcohol with an average of 5 moles ethylene oxide and Dobanol 25-7 is an
ethoxylated C 12-C 15 fatty alcohol with an average of 7 moles of ethylene
oxide per
mole of fatty alcohol.
Other examples of suitable ethoxylated alcohol nonionic surfactants include
Tergitol 15-S-7 and Tergitol 15-S-9, both of which are secondary alcohol
ethoxylates that have been commercially marketed by Union Carbide Corporation.
The former is a mixed ethoxylation product of C 11 to C 15 linear secondary
alkanol
with 7 moles of ethylene oxide and the latter is a similar product but with 9
moles of
ethylene oxide being reacted.
Other types of alcohol ethoxylate nonionics useful in the present
compositions are higher molecular weight nonionics, such as Neodol 45-11,
which
are similar ethylene oxide condensation products of higher fatty alcohols,
with the
higher fatty alcohol being of 14-15 carbon atoms and the number of ethylene
oxide
groups per mole being about 11. Such products have also been commercially
marketed by Shell Chemical Company.
Ethoxylated alcohol nonionic co-surfactants will frequently comprise from
about 0.2% to 2% of the compositions herein. More preferably, such ethoxylated
alcohols will comprise from about 0.5% to 1.5% of the compositions.
Another type of nonionic co-surfactant suitable for use in combination with
the polyhydroxy fatty acid amides in the nonionic surfactant component herein
comprises the ethylene oxide-propylene oxide block co-polymers that function
as
polymeric surfactants. Such block co-polymers comprise one or more groups
which
are hydrophobic and which contain mostly ethylene oxide moieties and one or
more
hydrophobic groups which contain mostly propylene oxide moieties. Such groups
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are attached to the residue of a compound that contained one or more hydroxy
groups or amine groups. Such polymeric surfactants have a molecular weight
ranging from about 400 to 60,000.
' Preferred ethylene oxide-propylene oxide polymeric surfactants are those in
which propylene oxide is condensed with an amine, especially a diamine, to
provide
a base that is then condensed with ethylene oxide. Materials of this type are
marketed under the tradename Tetronic~. Similar structures wherein the
ethylene
diamine is replaced with a polyol such as propylene glycol are marketed under
the
tradename "Pluronic~". Preferred ethylene oxide-propylene oxide (EO-PO)
polymeric surfactants have an HLB which ranges from about 4 to 30, more
preferably about 10 to 20.
The ethylene oxide-propylene oxide block co-polymers used herein are
described in greater detail in Pancheri/Mao; U.S. Patent 5,167,872; Issued
December
2, 1992. This patent is incorporated herein by reference.
Ethylene oxide-propylene oxide block co-polymers will frequently be present
to the extent of from about 0.1 % to 2% of the compositions herein. More
preferably,
these polymeric surfactant materials will comprise from about 0.2% to 0.8% of
the
compositions herein.
Suds Boosters/Stabilizers
The compositions herein further include from about 2% to 6%, preferably from
about 3% to 6%, of a suds booster or stabilizer component such as betaine
surfactants, hydroxy-free fatty acid amides, amine oxide semi-polar nonionic
surfactants, and Cg_22 alkyl polyglycosides. Combinations of these suds
boosters/stablizers can also be used.
Betaine surfactants useful as suds boosters herein have the general formula:
(+) 1 2 (_)
R - N(R )2 - R COO
wherein R is a hydrophobic group selected from alkyl groups containing from
about
10 to about 22 carbon atoms, preferably from about 12 to about 18 carbon
atoms,
i
alkyl aryl and aryl alkyl groups containing a similar number of carbon atoms
with a
benzene ring being treated as equivalent to about 2 carbo 1 atoms, and similar
structures interrupted by amido or ether linkag~s; each R is an alkyl group
containing from 1 to about 3 carbon atoms; and R is an alkylene group
containing
from 1 to about 6 carbon atoms.
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Examples of preferred betaines are dodecyl dimethyl betaine, cetyl dimethyl
betaine, dodecyl amidopropyldimethyl betaine, tetradecyldimethyl betaine,
tetradecylamidopropyldimethyl betaine, and dodecyldimethylammonium hexanoate.
Other suitable amidoalkylbetaines are disclosed in U.S. Pat. Nos. 3,950,417;
4,137,191; and 4,375,421; and British Patent GB No. 2,103,236, all of which
are
incorporated herein by reference.
Hydroxy-free amide surfactants useful as suds boosters herein include the
ammonia, monoethanol, and diethanol amides of fatty acids having an acyl
moiety
containing from about 8 to about 18 carbon atoms. Such materials are
characterized
herein as "hydroxy-free" in order to distinguish them from the polyhydroxy
fatty
acid amides essentially used in the nonionic surfactant component hereinbefore
described. Accordingly, "hydroxy-free" amides, for purposes of this invention,
are
those wherein the acyl moiety contains no hydroxy substituents. These
materials are
represented by the formula:
1 S R 1 - CO - N(H)m - 1 (R20H}3 _ m
wherein R1 is a saturated or unsaturated, hydroxy-free aliphatic hydrocarbon
group
having from about 7 to 21, preferably from about I1 to 17 carbon atoms; R2
represents a methylene or ethylene group; and m is l, 2, or 3, preferably 1.
Specific
examples of such amides are monoethanol amine coconut fatty acid amide and
diethanolamine dodecyl fatty acid amide. These acyl moieties may be derived
from
naturally occurring glycerides, e.g., coconut oil, palm oil, soybean oil, and
tallow,
but can be derived synthetically, e.g., by the oxidation of petroleum or by
hydrogenation of carbon monoxide by the Fischer-Tropsch process. The
monoethanolamides and diethanolamides of C fatty acids are preferred.
12-14
Amine oxide semi-polar nonionic surfactants useful as suds
boosters/stabilizers
comprise compounds and mixtures of compounds having the formula:
R2
RI-(C2H40)n-N--_____O
R3
wherein R1 is an alkyl, 2-hydroxyalkyl, 3-hydroxyalkyl, or 3-alkoxy-2-
hydroxypropyl radical in which the alkyl and alkoxy, respectively, contain
from
about 8 to about 18 carbon atoms, R2 and R3 are each methyl, ethyl, propyl,
isopropyl, 2-hydroxyethyl, 2-hydroxypropyl, or 3-hydroxypropyl, and n is from
0 to
about 10. Particularly preferred are amine oxides of the formula:
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R2
R I _N_______p
R3
wherein R is a C alkyl and R and R are methyl or ethyl. The above
1 12-16 2 3
hydroxy-free amides, and amine oxides are more fully described in U.S. Patent
4,316,824, incorporated herein by reference.
Other surfactants suitable for use as suds boosters/stabilizers in the
compositions herein are the nonionic fatty alkylpolygiycosides. Such materials
have
the formula:
R20(CnH2n0)Y(Z)x
wherein Z is derived from glucose, R is a hydrophobic group selected from
alkyl,
alkylphenyl, hydroxyalkylphenyl, and mixtures thereof in which said alkyl
groups
contain from 8 to 22, preferably from 12 to 14 carbon atoms; n is 2 or 3
preferably 2,
y is from 0 to 10, preferably 0; and x is from 1.5 to 8, preferably from I.5
to 4, most
preferably from 1.6 to 2.7. U.S Patents 4,393,203 and 4,732,704, incorporated
by
reference, describe these alkyl polyglycoside surfactants.
Agueous Liquid Carrier
The light duty dishwashing detergent compositions herein further contain from
about 50% to 75% of an aqueous liquid carrier in which the other essential and
optional compositions components are dissolved, dispersed or suspended. More
preferably the aqueous liquid carrier will comprise from about 47% to 64% of
the
compositions herein.
One essential component of the aqueous liquid carrier is, of course, water.
The
aqueous liquid carrier, however, may contain other materials which are liquid,
or
which dissolve in the liquid carrier, at room temperature and which may also
serve
some other function besides that of a simple filler. Such materials can
include, for
example, hydrotropes, solvents and electrolytes for phase stability.
a) Hydrotrones
The aqueous liquid carrier may comprise one or more materials which are
hydrotropes. Hydrotropes suitable for use in the compositions herein include
the
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C1-C3 alkyl aryl sulfonates, C6-C12 alkanols, C1-C6 carboxylic sulfates and
sulfonates, urea, C 1-C6 hydrocarboxylates, C 1-C4 carboxylates, C~-C4 organic
diacids and mixtures of these hydrotrope materials.
Suitable C1-C3 alkyl aryl sulfonates include sodium, potassium, and
5 ammonium xylene sulfonates; sodium, potassium and ammonium toluene
sulfonates; sodium, potassium and ammonium cumene sulfonates; and sodium,
potassium and ammonium substituted or unsubstituted naphthalene sulfonates and
mixtures thereof.
Suitable C1-Cg carboxylic sulfate or sulfonate salts are any water soluble
salts
10 or organic compounds comprising 1 to 8 carbon atoms (exclusive of
substituent
groups), which are substituted with sulfate or sulfonate and have at least one
carboxylic group. The substituted organic compound may be cyclic, acylic or
aromatic, i.e. benzene derivatives. Preferred alkyl compounds have from 1 to 4
carbon atoms substituted with sulfate or sulfonate and have from 1 to 2
carboxylic
groups. Examples of this type of hydrotrope include sulfosuccinate salts,
sulfophthalic salts, sulfoacetic salts, m-sulfobenzoic acid salts and diester
sulfosuccinates, preferably the sodium or potassium salts as disclosed in U.S.
3,915,903.
Suitable C1-C4 hydrocarboxylates and C1-C4 carboxylates for use herein
include acetates and propionates and citrates. Suitable C2-C4 diacids for use
herein
include succinic, glutaric and adipic acids.
Other compounds which deliver hydrotropic effects suitable for use herein as a
hydrotrope include C6-C 12 alkanols and urea.
Preferred hydrotropes for use herein are sodium, potassium and ammonium
cumene sulfonate; sodium, potassium and ammonium xylene sulfonate; sodium,
potassium and ammonium toluene sulfonate and mixtures thereof. Most preferred
are sodium cumene sulfonate and sodium xylene suifonate and mixtures thereof.
These preferred hydrotrope materials can be present in the composition to the
extent
of from about 3% to 8% by weight.
b) Solvents
A variety of water-miscible liquids such as lower alkanols, diols, other
polyols,
ethers, amines, and the like may be used as part of the aqueous liquid
carrier.
Particularly preferred are the C1-4 alkanols. Such solvents can be present in
the
compositions herein to the extent of from about 3% to 8%.
c) Electrolytes
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A variety of water-soluble salts may be used as an electrolyte in the aqueous
liquid carrier component of the compositions herein. These include such salts
as
sodium chloride, potassium chloride, sodium citrate, sodium acetate, sodium
sulfate,
potassium sulfate, and the like. Most preferably, the electrolyte is sodium or
potassium chloride.
If used, electrolytes can comprise from about 2.~% to 8% of the composition.
More preferably, electrolyte will be used in the compositions herein in an
amount
ranging from about 1.5% to 4.5%.
Agent for pH Control
Alkaline pH products, and alkaline aqueous dishwashing solutions formed
therefrom, which contain the particular combination of surfactants of the
compositions herein, are especially effective in removing greasy soils from
dishware, especially heavily soiled dishware. Accordingly, the compositions of
the
present invention will also essentially contain a pH control agent which is
sufficient
to maintain the pH of a 10% aqueous solution of the composition within the
range of
from about 9 to 11. More preferably, the compositions herein will be more
alkaline
in nature with a 10% solution pH of from about 10.0 to 10.5.
It is especially preferred that the pH control agent be able to maintain the
pH of
dilute solutions comprising the aqueous dishwashing solutions of this
invention.
Preferably, the pH control agent is effective for maintaining the pH of a 3%
aqueous
solution of the composition within the range of from about 9.5 to about 10.8,
preferably from about 9.8 to about 10.5. Even more preferably the pH control
agent
is effective for maintaining the pH of a 0.3% aqueous solution of the
composition
within the range of from about 9.8 to about 11.0, preferably from about 10.0
to about
11Ø
The pH control agent used to provide the requisite pH characteristics to the
dishwashing detergents herein can be any low molecular weight organic or any
organic material that provides alkalinity. Useful inorganic salts include
water-
soluble carbonates, bicarbonates, borates, phosphates, chlorides or silicates.
Useful
organic materials with add alkalinity include the alkanolamines. Highly
preferred
pH control agents comprise the alkali metal carbonates, especially sodium or
potassium carbonate.
The pH control agent will generally be present in the compositions of the
invention herein at a level of from about 0.2% to 6%, preferably from about 2%
to
5%, by weight of the composition.
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Avoidance of Divalent Metal Ions
The alkaline nature of the liquid dishwashing detergent compositions herein
creates the need to avoid the incorporation of any divalent metal ions which
might
form hydroxide precipitates under the pH conditions specified for the liquid
detergent products herein. Thus, the compositions of the present invention
will
generally be substantially free of any source of calcium and/or magnesium
ions.
This is the case even though Ca and/or Mg sources are conventionally included
in
liquid dishwashing detergent compositions of lower pH.
Improved Temperature Stability
Liquid dishwashing detergent compositions of this invention having an
especially desirable high and/or low temperature stability can be prepared by
selecting certain types and amounts of components from those hereinbefore
described. By utilizing potassium salts of the electrolyte and/or pH control
agent,
room and high temperature stability of the product can be improved since such
potassium salts have a reduced tendency to form visible precipitates at higher
temperatures. By utilizing relatively lower concentrations of the anionic
surfactant
component, i.e., concentrations of about 31 % or less, the tendency of the
surfactant
system to form visible precipitates at lower temperatures is reduced.
Optional Ingredients
Preferred optional ingredients in the dishwashing compositions herein include
ancillary surfactants, enzymes such as protease, a stabilizing system for the
enzymes
and ihickners. These and other optional ingredients are described as follows:
a) Ancillary Surfactants
The compositions herein may contain a wide variety of ancillary surfactants in
addition to the essentially utilized surfactants hereinbefore described. Such
ancillary
surfactants, for example, can include Cg_22 alkyl sulfates; C9_ 15 alkyl
benzene
sulfonates; Cg_22 olefin sulfonates; Cg_22 paraffin sulfonates; Cg_22 alkyl
glyceryl
ether sulfonates; fatty acid ester sulfonates; secondary alcohol sulfates; C
12-16 alkyl
ethoxy carboxylates; C 11-16 secondary soaps; ampholytic detergent
surfactants; and
zwitterionic detergent surfactants.
b) Protease and/or Other Enzymes
The compositions of this invention can also optionally contain from about
0.001% to about 5%, more preferably from about 0.003% to about 4%, most
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13
preferably from about 0.005% to about 3%, by weight, of active protease, i.e.,
proteolytic, enzyme. Protease activity may be expressed in Anson units (AU.)
per
kilogram of detergent composition. Levels of from 0.01 to about 150,
preferably
' from about 0.05 to about 80, most preferably from about 0.1 to about 40 AU.
per
kilogram have been found to be acceptable in compositions of the present
invention.
Useful proteolytic enzymes can be of animal, vegetable or microorganism
(preferred) origin. More preferred is serine proteolytic enzyme of bacterial
origin.
Purified or nonpurified forms of this enzyme may be used. Proteolytic enzymes
produced by chemically or genetically modified mutants are included by
definition,
as are close structural enzyme variants. Particularly preferred is bacterial
serine
proteolytic enzyme obtained from Bacillus subtilis and/or Bacillus
licheniformis.
Suitable proteolytic enzymes include Novo Industri A/S Alcalase~ {preferred),
Esperase~ , Savinase~ (Copenhagen, Denmark), Gist-brocades' Maxatase~,
Maxacal~ and Maxapem 15~ (protein engineered Maxacal~) (Delft, Netherlands),
and subtilisin BPN and BPN'(preferred), which are commercially available.
Preferred proteolytic enzymes are also modified bacterial serine proteases,
such as
those made by Genencor International, Inc. (San Francisco, California) which
are
described in European Patent EP-B-251,446, granted December 28, 1994 and
published January 7, 1988 (particularly pages 17, 24 and 98) and which are
also
called herein "Protease B". U.S. Patent 5,030,378, Venegas, issued July 9,
1991,
refers to a modified bacterial serine proteolytic enzyme (Genencor
International)
which is called "Protease A" herein (same as BPN'). In particular see columns
2 and
3 of U.S. Patent 5,030,378 for a complete description, including amino
sequence, of
Protease A and its variants. Preferred proteolytic enzymes, then, are selected
from
the group consisting of Alcalase ~ (Novo Industri A/S), BPN', Protease A and
Protease B (Genencor), and mixtures thereof. Protease B is most preferred.
Another preferred protease, referred to as "Protease D" is a carbonyl
hydrolase variant having an amino acid sequence not found in nature, which is
derived from a precursor carbonyl hydrolase by substituting a different amino
acid
for a plurality of amino acid residues at a position in said carbonyl
hydrolase
equivalent to position +76, preferably also in combination with one or more
amino
acid residue positions equivalent to those selected from the group consisting
of +99,
+101, +103, +104, +107, +123, +27, +105, +i09, +126, +128, +135, +156, +166,
+195, +197, +204, +206, +210, +216, +217, +218, +222, +260, +265, and/or +274
according to the numbering of Bacillus amyloliquefaciens subtilisin, as
described in
WO 95/10615 published April 20, 1995 by Genencor International.
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Useful proteases are also described in PCT publications: WO 95/30010
published November 9, 1995 by The Procter & Gamble Company; WO 95/30011
published November 9, 1995 by The Procter & Gamble Company; WO 95/29979
published November 9, 1995 by The Procter & Gamble Company.
Other optional enzymes such as lipase and/or amylase may be also added to the
compositions of the present invention for additional cleaning benefits.
c) Enzyme Stabilizing S stem
The preferred compositions herein may additionally comprise from about
0.001 % to about 10%, preferably from about 0.005% to about 8%, most
preferably
from about 0.01 % to about 6%, by weight of an enzyme stabilizing system. The
enzyme stabilizing system can be any stabilizing system which is compatible
with
the protease or other enzymes used in the compositions herein. Such
stabilizing
systems can comprise boric acid, propylene glycol, short chain carboxylic
acid,
boronic acid, polyhydroxyl compounds and mixtures thereof such as are
described in
U.S. Patents 4,261,868, Hora et al, issued April 14, 1981; 4,404,115, Tai,
issued
September 13, 1983; 4,318,818, Letton et al; 4,243,543, Guildert et al issued
January
6, 1981; 4,462,922, Boskamp, issued July 31, 1984; 4,532,064, Boskamp, issued
July 30, 1985; and 4,537,707, Severson Jr., issued August 27, 1985, all of
which are
incorporated herein by reference.
Additionally, from 0 to about 10%, preferably from about 0.01 % to about 6%
by weight, of chlorine bleach and oxygen bleach scavengers can be added to
compositions of the present invention to prevent chlorine bleach species
present in
many water supplies from attacking and inactivating the enzymes, especially
under
alkaline conditions. While chlorine levels in water may be small, typically in
the
range from about 0.5 ppm to about 1.75 ppm, the available chlorine in the
total
volume of water that comes in contact with the enzyme during dishwashing is
usually large; accordingly, enzyme stability in-use can be problematic.
Suitable chlorine scavenger anions are salts containing ammonium cations.
These can be selected from the group consisting of reducing materials like
sulfite,
bisulfate, thiosulfite, thiosulfate, iodide, etc., antioxidants like
carbonate, ascorbate,
etc., organic amines such as ethylenediaminetetracetic acid (EDTA) or alkali
metal
salt thereof and monoethanolamine (MEA), and mixtures thereof.
d) Thickener
The dishwashing detergent compositions herein may also contain a thickener
material. Many suitable polymeric thickeners are known in the art. A preferred
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thickener for use in the compositions of the present invention is
hydroxypropyl
methyicellulose.
Hydroxypropyl methylcellulose polymer has a number average molecular
weight of about 50,000 to 125,000 and a viscosity of a 2 wt.% aqueous solution
at
25°C. (ADTMD2363) of about 50,000 to about 100,000 cps. An especially
preferred hydroxypropyl cellulose polymer is Methocel~ J75MS-N wherein a 2.0
wt.% aqueous solution at 25°C. has a viscosity of about 75,OOU cps.
Especially
preferred hydroxypropyl cellulose polymers are surface treated such that the
hydroxypropyl cellulose polymer will ready disperse at 25 °C. into an
aqueous
solution having a pH of at least about 8.5.
When formulated into the dishwashing detergent compositions of the present
invention, the thickener such as hydroxypropyl methylcellulose polymer will
impart
to the detergent composition a Brookfield viscosity of from about 500 to 3500
cps at
25°C. More preferably, a hydroxypropyl methylcellulose material will be
used to
impart a viscosity of from about 1000 to 3000 cps at 25°C. For purposes
of this
invention, viscosity is measured with a Brookfield LVTDV-11 viscometer
apparatus
using an RV #2 spindle at 12 rpm.
The dishwashing detergent compositions herein can contain from about 0.2%
to 2% of a thickener, especially a hydroxypropyl methylcellulose thickener.
More
preferably, such a thickener can comprise from about 0.5% to 2.5% of the
compositions herein.
e) Miscellaneous Optional Ingredients
Other conventional optional ingredients which are usually used in additive
levels of below about 5% include opacifiers, antioxidants, bactericides, dyes,
perfumes, and the like. Furthermore, detergency builders can also be present
in the
compositions herein in amounts of from 0% to about SO%, preferably from about
2%
to about 30%, most preferably from about 5% to about 15%. It is typical in
light-
duty liquid or gel dishwashing detergent compositions to have no detergent
builder
present. However, even though calcium and magnesium ion sources are excluded
from the compositions herein,certain compositions may contain trace amounts of
magnesium or calcium ions as impurities. Such compositions may require the
additional presence of low levels of, preferably from 0 to about 10%, more
preferably from about 0.5% to about 3%, chelating agents selected from the
group
consisting of bicine/bis(2-ethanol)blycine), citrate N-(2-hydroxylethyl)
iminodiacetic acid (HIDA), N-(2,3-dihydroxy- propyl) diethanolamine, 1,2-
diamino-
2-propanol N,N'-tetramethyl-1,3-diamino-2-propanol, N,N-bis(2-
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hydroxyethyl)glycine (a.k.a. bicine), and N-tris (hydroxymethyl)methyl glycine
(a.k.a. tricine) are also preferred. Mixtures of any of the above are
acceptable.
Composition Preparation
The liquid or gel dishwashing detergent compositions herein may be prepared
by combining the essential and optional ingredients together in any convenient
order
using suitable agitation to form a homogeneous product. Preferred methods for
making detergent compositions of the type disclosed herein, and for preparing
various components of such compositions, are described in greater detail in
Ofosu-
Asante: U.S. 5,474,710: Issued December 12, 1995, incorporated herein by
reference.
Dishwashing Method
Soiled dishes can be contacted with an effective amount, typically from about
0.5 ml. to about 20 ml. (per 25 dishes being treated), preferably from about 3
ml. to
about 10 ml., of the detergent composition of the present invention. The
actual
amount of liquid detergent composition used will be based on the judgment of
user,
and will typically depend upon factors such as the particular product
formulation of
the composition, including the concentration of active ingredient in the
composition,
the number of soiled dishes to be cleaned, the degree of soiling on the
dishes, and
the like. The particular product formulation, in turn, will depend upon a
number of
factors, such as the intended market (i.e., U.S., Europe, Japan, etc.) for the
composition product. The following are examples of typical methods in which
the
detergent compositions of the present invention may be used to clean dishes.
These
examples are for illustrative purposes and are not intended to be limiting.
In a typical U.S. application, from about 3 ml. to about 15 ml., preferably
from
about S ml. to about 10 ml. of a liquid detergent composition is combined with
from
about 1,000 ml. to about 10,000 ml., more typically from about 3,000 ml. to
about
5,000 ml. of water in a sink having a volumetric capacity in the range of from
about
5,000 ml. to about 20,000 ml., more typically from about 10,000 ml. to about
15,000
ml. The detergent composition has a surfactant mixture concentration of from
about
21 % to about 44% by weight, preferably from about 25% to about 40% by weight.
The soiled dishes are immersed in the sink containing the detergent
composition and
water, where they are cleaned by contacting the soiled surface of the dish
with a
cloth, sponge, or similar article. The cloth, sponge, or similar article may
be
immersed in the detergent composition and water mixture prior to being
contacted
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with the dish surface, and is typically contacted with the dish surface for a
period of
time ranging from about 1 to about 10 seconds, although the actual time will
vary
with each application and user. The contacting of the cloth, sponge, or
similar
' article to the dish surface is preferably accompanied by a concurrent
scrubbing of the
dish surface.
In a typical European market application, from about 3 ml. to about 15 ml.,
preferably from about 3 mi. to about 10 ml. of a liquid detergent composition
is
combined with from about 1,000 ml. to about 10,000 ml., more typically from
about
3,000 ml. to about ~,OOU ml. of water in a sink having a volumetric capacity
in the
range of from about 5,000 ml. to about 20,000 ml., more typically from about
10,000 ml. to about 15,000 ml. The detergent composition has a surfactant
mixture
concentration of from about 20% to about 50% by weight, preferably from about
30% to about 40%, by weight. The soiled dishes are immersed in the sink
containing the detergent composition and water, where they are cleaned by
contacting the soiled surface of the dish with a cloth, sponge, or similar
article. The
cloth, sponge, or similar article may be immersed in the detergent composition
and
water mixture prior to being contacted with the dish surface, and is typically
contacted with the dish surface for a period of time ranging from about 1 to
about 10
seconds, although the actual time will vary with each application and user.
The
contacting of the cloth, sponge, or similar article to the dish surface is
preferably
accompanied by a concurrent scrubbing of the dish surface.
In a typical Latin American market application, from about 1 ml. to about 50
ml., preferably from about 2 ml. to about 10 ml. of a detergent composition is
combined with from about 50 ml. to about 2,000 ml., more typically from about
100
ml. to about 1,000 ml. of water in a bowl having a volumetric capacity in the
range
of from about 500 ml. to about 5,000 ml., more typically from about 500 ml. to
about 2,000 ml. The detergent composition has a surfactant mixture
concentration
of from about 5% to about 40% by weight, preferably from about 10% to about
30%
by weight. The soiled dishes are cleaned by contacting the soiled surface of
the dish
with a cloth, sponge, or similar article. The cloth, sponge, or similar
article may be
immersed in the detergent composition and water mixture prior to being
contacted
with the dish surface, and is typically contacted with the dish surface for a
period of
r
time ranging from about 1 to about 10 seconds, although the actual time will
vary
with each application and user. The contacting of the cloth, sponge, or
similar
article to the dish surface is preferably accompanied by a concurrent
scrubbing of the
dish surface.
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Another dishwashing method used worldwide involves direct application of the
detergent compositions herein, either neat or diluted in a dispenser bottle.
onto the
soiled dishes to be cleaned. This can be accomplished by using a device for
absorbing liquid dishwashing detergent, such as a sponge or dishrag, which is
placed
directly into a separate quantity of undiluted or somewhat diluted liquid
dishwashing
composition for a period of time typically ranging from about I to about 5
seconds.
The absorbing device, and consequently the undiluted or somewhat diluted
liquid
dishwashing composition, can then be contacted individually with the surface
of
each of the soiled dishes to remove food soil. The absorbing device is
typically
contacted with each dish surface for a period of time ranging from about 1 to
about
10 seconds, although the actual time of application will be dependent upon
factors
such as the degree of soiling of the dish. The contacting of the absorbing
device
with the dish surface is preferably accompanied by concurrent scrubbing. Prior
to
contact and scrubbing, this method may involve immersing the soiled dishes
into a
i S water bath without any liquid dishwashing detergent. After scrubbing, the
dish can
be rinsed under running water.
The following Examples illustrate the invention and facilitate its
understanding.
EXAMPLE I
A light-duty liquid dishwashing detergent formula having the following
composition is prepared:
In redient Concentration
Wt.%
Sodium C 12_ 13 alkyl ethoxy 34
( 1-3) sulfate
C 12-14 Glucose amide 4
Coconut amine oxide 5
EO/PO block co-polymer - Tetronic~0.3
704
Ethanol 7
Sodium xylene sulfonate
Neodol~ C 11 E9 alcohol ethoxylate1
Perfume 0.2
Sodium chloride 4.0
Sodium carbonate 3.0
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Water and minors Balance to 100%
pH @ 10% (as made) 10.1
EXAMPLE II
A light-duty liquid dishwashing detergent compo sition of especially
desirable
high and/or low temperature stability is preparedg the following
havin formula:
Ingredient Concentration
Wt.%
Sodium C12-13 alkyl ethoxy (1-3) sulfate 31
C12-14 Glucose amide 4
Coconut amine oxide 4
EO/PO block co-polymer - Tetronic~ 704 0.4
Ethanol
Sodium xylene sulfonate 5
Neodol~ C 11 E9 alcohol ethoxylate 1
Perfume 0,2
Potassium chloride 2.5
Potassium carbonate 2.5
Water and minors Balance to 100%
pH @ 10% (as made) 10.5
