Note: Descriptions are shown in the official language in which they were submitted.
WO 94/29428 PCT/US94/06207
-1-
CONCENTRATED NIL-PHOSPHATE LIQUID AUTOMATIC DISHWASHING
DETERGENT COMPOSITIONS CONTAINING ENZYME
TECHNICAL FIELD
This invention is in the field of liquid automatic dishwashing compositions.
More
specifically, the invention relates to concentrated compositions containing
non-phosphate builders,
enzymes, and a potassium/sodium weight ratio of at least about 0.01.
BACKGROUND OF THE INVENTION
Because of their convenience, dispensing characteristics 'and aesthetics,
liquid and/or gel
automatic dishwashing detergent compositions are a popular alternative to
granular compositions
among consumers. However, liquid and/or gel formulations often do not deliver
the same
effective cleaning, spotting and filming performance as a granular
composition.
To clean effectively, conventional liquid/gel and granular automatic
dishwashing detergents
contain chlorine bleach, phosphate builders and have high alkalinity (i. e.
silicate, carbonate and
caustic). See, for example, U.S. Patents 4,116,849, Leikhim, issued September
26, 1978,
5,064,553, Dixit et al, issued November 12, 1991 and 4,917,812, Cilley, issued
April 17, 1990.
Incorporation of chlorine bleaches requires special processing, storage steps,
and the use of
chlorine bleach stable raw materials (which are mostly inorganic in nature).
Automatic detergent
compositions have been disclosed which use enzymes in place of chlorine
bleach, for example,
U. S. Patents 4,162,987, Maguire et al, issued July 31, 1979, 4,101,457, Place
et al, issued July 18,
1978 and 5,075,027, Dixit et al, issued December 24, 1991.
It has recently been found that a viscoelastic, thixotropic liquid automatic
dishwashing
detergent can be formed which has superior performance to conventional
liquid/gel products and
comparable performance to granular products. Surprisingly, a low alkaline
product pH (between
about 7 and about 11 ) liquid composition which is substantially free of
chlorine, and silicate,
exhibits enhanced cleaning, spotting, and filming ability. The cleaning
benefit is achieved via the
presence of enzymes, and surfactant and/or builder in the composition. Removal
of chlorine
bleach and a lower product pH also results in a composition which is safer to
dishwasher articles
(i.e. china, silverware, glass, and the like).
Because of increasing environmental concerns, there is a movement away from
phosphated
WO 94/29428 PCT/LTS94106207
compositions and excessive packaging materials. In order to maintain and
achieve superior
product performance without phosphate builders, more costly raw materials are
required (e.g.
enzymes and surfactants and new organic builders). Compaction or concentration
of the formula
composition has become a common means to help offset this economic upcharge,
while
simultaneously reducing solid waste.
However, the move from conventional formulations to concentrated formulas is
not a
simple matter of adding more active ingredients to conventional detergent
formulations. This is
especially true in the case of liquids where solubility of the ingredients is
a limiting factor. It has
now been found that a concentrated liquid automatic dishwashing detergent
composition
containing enzymes and non-phosphate builders) requires a potassium/sodium
weight ratio of at
least 0.01, preferably, between about 0.01 and about 10, in order to maintain
long term product
stability.
SL>MMARY OF THE INVENTION
The composition of this invention is a concentrated viscoelastic, thixotropic,
liquid
automatic dishwashing detergent composition comprising, by weight:
(a) from about 5% to about 50% of a non-phosphate detergent builder selected
from the
group consisting of water-soluble, alkali metal, ammonium or substituted
ammonium carbonates,
bicarbonates, borates, polyhydroxysulfonates, polyacetates, carboxylates,
polycarboxylates and
mixtures thereof;
(b) from about 0.0001% to about 5% of active detersive enzyme or enzymes;
(c) from about 0.1 % to about 10% of a viscoelastic, thixotropic thickener;
(d) sufficient pH adjusting agent to provide said composition with a product
pH between
about 7 and about 11; and
(e) from about 0.001 % to about 20% of an enzyme stabilizing system selected
from the
group consisting of calcium ion, propylene glycol, short chain carboxylic
acid, polyhydroxyl
compounds, boric acid, boronic acid, peptide aldehyde and mixtures thereof;
and
(f) water, wherein the aqueous phase includes both potassium and sodium ions
at a K/Na
weight ratio of at least about 0.01;
wherein said composition is substantially free of chlorine bleach, silicate,
and phosphate.
A particularly preferred embodiment of this invention is a gel automatic
dishwashing
detergent composition further comprising an organic dispersant, a detergent
surfactant and/or a
chlorine
scavenger.
WO 94/29428 PCT/US94/06207
-3-
DETAILED DESCRIPTION OF THE INVENTION
The present invention encompasses viscoelastic, thixotropic, liquid automatic
detergent
compositions which exhibit enhanced performance in the absence of chlorine
bleach, silicate, and
phosphate. These detergent compositions contain the following components by
weight of the
composition:
(a) from about 5% to about 50% of a non-phosphate detergent builder selected
from the
goup consisting of water-soluble, alkali metal, ammonium or substituted
ammonium carbonates,
bicarbonates, borates, polyhydroxysulfonates, polyacetates, carboxylates,
polycarboxylates and
mixtures thereof;
(b) from about 0.0001% to about 5% of active detersive enzyme or enzymes;
(c) from about 0.1 % to about 10% of a viscoelastic, thixotropic thickener;
(d) sufficient pH adjusting agent to provide said composition with a product
pH between
about 7 and about 11; and
(e) from about 0.001 % to about 20% of an enzyme stabilizing system selected
from the
goup consisting of calcium ion, propylene glycol, short chain carboxylic acid,
polyhydroxyl
compounds, boric acid, boronic acid, peptide aldehyde and mixtures thereof;
and
(f) water, wherein the aqueous phase includes both potassium and sodium ions
at a K/Na
weight ratio of at least about 0.01;
wherein :::aid composition is substantially free of chlorine bleach, silicate,
and phosphate.
Various other optional ingedients, such as fatty acids, oxygen bleaches,
perfumes, dyes,
suds control agents, and organic dispersants, can be added to provide
additional performance,
product stability, and aesthetic benefits.
Tt~ ~ components result in a viscoelastic, thixotropic, liquid automatic
dishwashing
detergen~ ,;omposition which exhibits cleaning, spotting and filming
performance superior to
conventional liquid automatic dishwashing detergent compositions, and equal to
or better than
conventional ganular automatic dishwashing detergent compositions. A
particularly preferred
composition is a gel formulation.
The term thixotropic means the material exhibits a decrease in viscosity with
increasing
shear stress. In other words, it exhibits high viscosity when subjected to low
shear stress and
lower viscosity when subjected to higher shear stress. A viscoelastic liquid
exhibits a steady state
flow behavior after a constant shear stress has been applied for a
sufficiently long period of time.
The term "substantially free" is defined herein to pertain to substances in
the invention that
are not intentionally added, but could be present as trace impurities in other
raw material
feedstocks. Preferably, the compositions of the present invention comprises
less than 0.5% form
of phosphorous, and less than 0.2% silicate. No level of chlorine bleach
species is acceptable;
WO 94/29428 ~ PCT/US94/06207
2,~~51~~
-4-
however, if present chlorine scavengers discussed herein can be added to the
composition.
All percentages herein refer to weight percent of active material in the final
composition
unless otherwise noted.
Detergency Builder
The detergency builders used can be any of the non-phosphate detergency
builders known
in the art, which include the various water-soluble, alkali metal, ammonium or
substituted
ammonium carbonates, bicarbonates, borates, polyhydroxysulfonates,
polyacetates, carboxylates
(e.g. citrates), and polycarboxylates. Preferred are the alkali metal,
especially sodium and
potassium, salts of the above and mixtures thereof.
The amount of builder is from about 5% to about 50%, preferably from about 8%
to about
40%, most preferably from about 10% to about 30% by weight of the automatic
dishwashing
detergent composition.
Examples of non-phosphorus, inorganic builders are sodium and potassium
carbonate,
bicarbonate, and sesquicarbonate.
Water-soluble, non-phosphorus organic builders useful herein include the
various alkali
metal, ammonium and substituted ammonium polyacetates, carboxylates (e.g.
citrates),
polycarboxylates and polyhydroxysulfonates. Examples of polyacetate and
polycarboxylate
builders are the sodium, potassium, lithium, ammonium and substituted ammonium
salts of
ethylene diamine tetraacetic acid, nitrilotriacetic acid, tartrate
monosuccinic acid, tartrate
disuccinic acid, oxydisuccinic acid, carboxy methyloxysuccinic acid, mellitic
acid, benzene
polycarboxylic acids, and citric acid.
Preferred detergency builders have the ability to remove metal ions other than
alkali metal
ions from washing solutions by sequestration, which as defined herein includes
chelation, or by
precipitation reactions. Some of the above-described detergency builders
additionally serve as
buffering agents (pFi adjusting), and/or chlorine scavengers.
Particularly preferred automatic dishwashing detergent compositions of the
invention
contain, by weight of the automatic dishwashing detergent composition, from
about 5% to about
50%, preferably from about 8% to about 30%, most preferably from about 10% to
about 30%, of
carbonate, citrate, and mixtures thereof.
The compositions of this invention must include sufficient amounts of
potassium and
sodium ions to provide a finished product KlNa weight ratio of at least about
0.01, preferably
between about 0.01 and about 10, more preferably between about 0.1 and about
1.0, even more
preferably between about 0.1 and about 0.8, most preferably between about 0.1
and about 0.5.
The potassium and sodium ions can be incorporated into the composition from
the alkali metal
WO 94/29428 ~, ~ ~ PCT/US94/06207
cation of the detergent builder salt(s), or alkali metal hydroxide(s), or as
the alkali metal cation of
any other component of the composition. In determining the total finished
product K/Na weight
ratio, all of these sources should be taken into consideration.
Not to be bound by theory, it is believed that increasing the water solubility
of the detergent
salts is the means to achieve high builder levels while maintaining long term
stability. In the
compact formulations of the present invention, there is a reduction in the
amount of available
water. Therefore, it becomes more difficult to solubilize the builder salts,
especially when only
sodium salts are used. It has been found that the use of a11 sodium builder
salts in matrices similar
to this invention results in excessive crystal growth/precipitation when the
product is exposed to
long term storage (greater than one month) and/or harsh conditions. It has
been found that a
stable composition can be formed by incorporating potassium ions into
compositions of the
present invention.
The finished product K/Na weight ratio is directly proportional to the weight
percent of
detergent components/salts incorporated in the composition. A higher weight
percent of
detergent components in the composition requires a higher finished product
K/Na weight ratio to
achieve acceptable finished product stability. For example, in composition of
the present
invention containing citrate and carbonate builders, the K/Na ratio should be
between about 0.01
and about 0.20 for builder levels between about 5% and 10%; between about 0.05
and 1.50 for
builder levels between about 10% and about 30%; and between about 0.6 and 10.0
for builder
levels between 30% and 50%.
Detersive Enzyme
The compositions of this invention can contain from about 0.0001 % to about
5%, more
preferably from about 0.001% to about 1%, most preferably from about 0.005% to
about 0.5%,
by weight, of active detersive enzyme. Weight percent of "active detersive
enzyme" is defined by
the actual weight percent of the enzyme present in the composition - it does
not include the
weight percent of other materials commonly included in commercial enzyme
feedstocks (e.g.
solvents, stabilizers, residuals).
The preferred detersive enzyme is selected from the group consisting of
protease, amylase,
lipase and mixtures thereof. Most preferred are protease or amylase or
mixtures thereof.
The proteolytic enzyme 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, Bacillus
subtilis and/or Bacillus
-6-
licheniformis.
Suitable proteolytic enzymes include Alcalase~, Esperase~, Durazym~, Savinase~
(preferred); Maxatase~, Maxacal~ (preferred), and Maxapem~ 1 S (protein
engineered Maxacal);
Purafect~ (preferred) and subtilisin BPN and BPN'; which are commercially
available. Preferred
proteolytic enzymes are also modified bacterial serine proteases, such as
those described in
European Patent Application 2S 1,446, published January 7, 1988 (particularly
pages 17, 24 and
98), and which is called herein "Protease B", in European Patent Application
199,404, Venegas,
published October 29, 1986, which refers to a modified bacterial serine
proteolytic enzyme which
is called "Protease A" herein and in PCT Application Number WO 9l/02792,
Wilson et al,
published March 7, 199l which is called "BLAP" herein. Preferred proteolytic
enzymes, then, are
selected from the group consisting of Savinase~, Alcalase~, Esperase~,
Maxacal~, Purafect~,
BPN', Protease A and Protease B, and mixtures thereof. Savinase~ or "Protease
B" is most
preferred.
Suitable lipases for use herein include those of bacterial, animal, and fungal
origin,
including those from chemically or genetically modified mutants.
Suitable bacterial lipases include those produced by Pseduomonas, such as
Pseudomonas
stutzeri ATCC 19.1 S4, as disclosed in British Patent 1,372,034. Suitable
lipases include those
which show a positive immunological cross-reaction with the antibody of the
lipase produced from
the microorganism Pseudomonas fluorescens IAM 10S7. This lipase and a method
for its
purification have been described in Japanese Patent Application S3-20487, laid
open on February
24, 1978. This lipase is available under the trade mark Lipase P "Amano,"
hereinafter referred to
as "Amano-P." Such lipases should show a positive immunological cross reaction
with the
Amano-P antibody, using the standard and well-known immunodiffusion procedure
according to
Oucheterlon (Acta. Med. Scan., 133, pages 76-79 (19S0)). These lipases, and a
method for their
immunological cross-reaction with Amano-P, are also described in U.S. Patent
4,707,291, Thom et
al., issued November 17, 1987. Typical examples thereof are the Amano-P
lipase, the lipase ex
Pseudomonas fra~i FERM P l339 (available under the trade mark Amano-B), lipase
ex
Pseudomonas nitroreducens var. lipolyticum FERM P 1338 (available under the
trade mark
Amano-CES), lipases ex Chromobacter viscosum var. lipolyticum NRRIb 3673, and
further
Chromobacter viscosum lipases, and lipases ex Pseudomonas ladioli. A preferred
lipase is
derived from Pseudomonas pseudoalcali eves, which is described in Granted
European Patent,
EP-B-0218272. Other lipases of interest are Amano AKG and Bacillis Sp lipase
(e.g. Solvay
enzymes).
Other Iipases which are of interest where they are compatible with the
composition are
those described in EP A 0 339 68l, published November 28, l990, EP A 0 38S
401, published
-7-
September 5, 1990, EO A 0 218 272, published April 15, 1987, and PCT/DK
88/00l77, published
May 18, 1989.
Suitable fungal lipases include those produced by Humicola lanuginosa and
Thermomyces
lanu inosus. Most preferred is lipase obtained by cloning the gene from
Humicola lanuginosa and
expressing the gene in Asper illus oryzae as described in European Patent
Application 0 258 068,
commercially available under the trade mark Lipolase~ from Novo-Nordisk.
Any amylase suitable for use in a dishwashing detergent composition can be
used in these
compositions. Amylases include for example, a-amylases obtained from a special
strain of B.
licheniforms, described in more detail in British Patent Specification No.
1,296,839. Amylolytic
enzymes include, for example, RapidaseT"', MaxamylT"'I, Termamyl~ and BAN'~"~.
Enzyme Stabilizing System
The preferred compositions herein comprise from about 0.001 % to about 20%,
preferably
from about 0.01 % to about 15%, most preferably from about 0.5% to about 12%,
by weight, of an
enzyme stabilizing system. The enzyme stabilizing system can be any
stabilizing system which is
compatible with the enzyme of the present invention. Such stabilizing systems
can comprise
calcium ion, boric acid, propylene glycol, short chain carboxylic acid,
boronic acid, polyhydroxyl
compounds, peptide aldehydes, and mixtures thereof. The level of calcium ion
should be selected
so that there is always some minimum level available for the enzyme, after
allowing for
complexation with builders, etc., in the composition. Any water-soluble
calcium salt can be used
as the source of calcium ion, including calcium chloride, calcium formate, and
calcium acetate. A
small amount of calcium ion, generally from about 0.05 to about 0.4 millimoles
per liter, is often
also present in the composition due to calcium in the enzyme and formula
water. Calcium ions
can be used with boric acid or a suitable salt of boric acid, described herein
below, in a
composition with a product pH between about 7 and about 9. However, calcium
ions and the salt
of boric acid can associate to from calcium borate which is insoluble in cold
water and under
certain product conditions can be insoluble above about pH 9. This precipitate
can lead to phase
instability, decrease in effective enzyme stabilization and undesired product
aesthetics. Therefore,
a sufficient amount of calcium ion and boric acid or the salt of boric acid
should be used to
achieve enzyme stability without affecting phase stability, enzyme stability,
or aesthetics. From
about 0% to about 1%, more preferably from about 0.05% to about 0.45% of
calcium formate is
preferred.
Other suitable enzyme stabilizing systems comprise polyols containing only
carbon,
hydrogen and oxygen atoms. They preferably contain from about 2 to about 6
carbon atoms and
from about 2 to about 6 hydroxy groups. Examples include propylene glycol
(especially 1,2-
propanediol, which is preferred), 1,2-butanediol, ethylene glycol, glycerol,
sorbitol, mannitol, and
c
.,~,:
-a
_g_
glucose. The polyol generally represents from about 0.001 % to about 20%,
preferably from about
1.5% to about 8%, by weight of the composition. Preferably, the weight ratio
of polyol to a boric
acid added is at least l, most preferably at least about 1.3.
The compositions can also contain the water-soluble short chain carboxylates
described in
U.S. Patent 4,318,8l8, Letton et al., issued March 9, 1982. The formates are
preferred and can be
used at levels from 0% to about 5%, preferably from about 0.075% to about
2.5%, most preferably
from about 0.1% to about 1.5%, by weight. Sodium formate is preferred.
Another stabilizing system comprises from about 0.05% to about 7%, preferably
from
about 0.1 % to about 5%, by weight of boric acid. The boric acid may be, but
is preferably not,
formed by a compound capable of forming boric acid in the composition. Boric
acid is preferred,
although other compounds such as boric oxide, borax, and other alkali metal
borates (e.g., sodium
ortho-, meta- and pyroborate, and sodium pentaborate) are suitable.
Still another enzyme stabilizing system includes polyhydroxyl compounds, such
as sugar
alcohols, monosaccharides and disaccharides as disclosed in the specification
of German Pat. No.
2,038,103, water-soluble sodium or potassium salts and water-soluble hydroxy
alcohols, as
disclosed in U.S. Published Patent Application B-458,819, Weber, published
April 13, l976;
diamines and polyamines, as disclosed in German Pat. No. 2,058,826; amino
acids, as disclosed in
German Pat. No. 2,060,485; and reducing agents, as disclosed in Japanese Pat.
No. 72-20235.
Further, in order to enhance its storage stability, the enzyme mixture may be
incorporated into the
detergent composition in a coated, encapsulated, agglomerated, prilled, or
noodled form in
accordance with, e.g., U.S. Patent 4,l62,987, Maguire et al, issued July 31,
1979.
Substituted boric acids (e.g. phenylboronic acid, butane boronic acid, and p-
bromo
phenylboronic acid) can also be used in place of boric acid. A particularly
preferred boronic acid is
an aryl boronic acid of the structure:
Y Y
t H
Y ;H n
OH
where x is selected from C,-C6 alkyl, substituted C,-C6 alkyl, aryl,
substituted aryl, hydroxyl,
hydroxyl derivative, amine C,-C6 alkylated amine, amine derivative, halogen,
nitro, thiol, thio
derivative, aldehyde, acid, acid salt, ester, sulfonate or phosphonate; each Y
is independently
selected from hydrogen, C,-C6 alkyl, substituted C,-C6 alkyl, aryl,
substituted aryl, hydroxyl,
-9-
hydroxyl derivative, halogen, amine, alkylated amine, amine derivative, nitro,
thiol, thiol
derivative, aldehyde, acid, ester, or sulfonate; and n is 0 to 4.
Yet another suitable stabilizing system includes a peptide aldehyde comprising
from 2 to
50 amino acids, or mixtures thereof. As used herein, the term peptide
aldehydes refers to
compounds comprising a peptidic chain wherein the C-terminal end of said chain
is converted from
a carboxylic group to an aldehyde group. Peptide aldehydes are known per se
and have been
described as well as processes for their manufacture, for instance in US
5,015,627, EP 185 930
and DE 32 00 8l2. Preferred peptide aldehydes for use herein comprise from 2
to 6 amino acids,
most preferably 3 to 4.
Thickenin~ Agent
The viscoelastic, thixotropic thickening agent in the compositions of the
present invention
is from about 0.1% to about 10%, preferably from about 0.25% to about 8%, most
preferably from
about 0.5% to about 5%, by weight of the detergent composition. Preferably,
the viscoelastic,
thixotropic thickening agent is free of any enzymatically reactive species.
Without being bound by
theory, it is believed that the enzymes) present in the automatic detergent
composition could
degrade the thickening agent which contains such species, resulting in a
Theologically unstable
product.
Preferably the thickening agent is a polymer with a molecular weight at least
about
500,000, preferably from about 500,000 to about 10,000,000. The polymeric
thickening agent can
be, but is not limited to, a cross-linked polycarboxylate polymer.
The preferred cross-linked polycarboxylate polymer is preferably a
carboxyvinyl polymer.
Such compounds are disclosed in U.S. Patent 2,798,053, issued on July 2, I957,
to Brown.
Methods for making carboxyvinyl polymers are also disclosed in Brown.
Carboxyvinyl polymers
are substantially insoluble in liquid, volatile organic hydrocarbons and are
dimensionally stable on
exposure to air.
Preferred polyhydric alcohols used to produce carboxyvinyl polymers include
polyols
selected from the class consisting of oligosaccarides, reduced derivatives
thereof in which the
carbonyl group is converted to an alcohol group, a pentaerythritol; most
preferred is sucrose or
pentaerythritol. It is preferred that the hydroxyl groups of the modified
polyol be etherified with
allyl groups, the polyol having at least two allyl ether groups per polyol
molecule. When the
polyol is sucrose, it is preferred that the sucrose have at least about five
allyl ether groups per
sucrose molecule. It is preferred that the polyether of the polyol comprise
from about 0.1% to
about 4% of the total monomers, more preferably from about 0.2% to about 2.5%.
Preferred monomeric olefinically unsaturated carboxylic acids for use in
producing
carboxyvinyl polymers used herein include monomeric, polymerizable, alpha-beta
monoolefinically
B
-10-
unsaturated lower aliphatic carboxylic acids; more preferred are monomeric
monoolefinic acrylic
acids of the structure
R
CHHz C---COOH
where R is a substituent selected from the group consisting of hydrogen and
lower alkyl groups;
for example, acrylic acid.
Various carboxyvinyl polymers, homopolymers and copolymers are commercially
available
from B.F. Goodrich Company, New York, N.Y., under the trade name Carbopol~.
These polymers
are also known as carbomers or polyacrylic acids. Carboxyvinyl polymers useful
in formulations
of the present invention include Carbopol 910 having a molecular weight of
about 7S0,000,
Carbopol 941 having a molecular weight of about 1,250,000, and Carbopols 934
and 940 having
molecular weights of about 3,000,000 and 4,000,000, respectively. More
preferred are the series
of Carbopols which use ethyl acetate and cyclohexane in the manufacturing
process, for example,
Carbopol 981, 2984, 980, and 1382.
Preferred polycarboxylate polymers of the invention are non-linear, water-
dispersible,
polyacrylic acid cross-linked with a polyalkenyl polyether and having a
molecular weight of at
least 7S0,000, preferably from about 7S0,000 to about 4,000,000.
Highly preferred examples of these polycarboxylate polymers for use in the
present
invention are Sokalan PHC-2SR, a polyacrylic acid available from BASF
Corporation, the
Carbopol series resins available from B.F. Goodrich, and the Polygel series
available from 3-V
Chemical Corporation. Mixtures of polycarboxylate polymers as herein described
may also
be used.
The polycarboxylate polymer thickening agent can be used alone or with
inorganic clays
(e.g. aluminum silicate, bentonite, fumed silica). The preferred clay
thickening agent can be either
naturally occurring or synthetic. A preferred synthetic clay is the one
disclosed in U.S. Patent
3,843,S98. Naturally occurring clays include some smectite and attapulgite
clays as disclosed in
U.S. Patent 4,824,S90.
Other types of thickeners which can be used in this composition include
natural gums, such
as xanthan gum, locust bean gum, guar gum, and the like. Semi-synthetic
thickeners such as the
cellulosic type thickeners: hydroxyethyl and hydroxymethyl cellulose
(ETHOCELT"' and
METHOCEL~ available from Dow Chemical) can also be used. Mixtures of polymeric
thickening agents, semi-synthetic, and natural thickeners herein described may
also be used.
Y
..
-11-
In the preferred viscoelastic thixotropic liquid automatic dishwashing
detergent
composition, the polycarboxylate polymer thickening agent provides an apparent
viscosity at high
shear of greater than about 250 centipoise and an apparent yield value of from
about 40 to about
800, and most preferably from about 60 to about 600, dynes/cm2 to the
composition.
Viscosity is a measure of the internal resistance to flow exhibited by a fluid
in terms of the
ratio of the shear stress to the shear rate. The yield value is an indication
of the shear stress at
which the gel strength is exceeded and flow is initiated. Yield value can be
measured herein with
a Brookfield RVT model viscometer with a T-bar B spindle at about 77~F (25~C)
utilizing a
Helipath drive during associated reading. The system is set to 0.5 rpm and a
torque reading is
taken for the composition to be tested after 30 seconds or after the system is
stable. The system is
stopped and the rpm is reset to 1.0 rpm. A torque reading is taken for the
same composition after
30 seconds or after the system is stable. Apparent viscosities are calculated
from the torque
readings using factors provided with the Brookfield viscometer. An apparent
Brookfield yield
value is then calculated as: Brookfield Yield Value = (apparent viscosity at
0.5 rpm - apparent
viscosity at 1 rpm)/100. This is the common method of calculation, published
in Carbopol
literature from the B.F. Goodrich Company and in other published references.
In the cases of most
of the formulations quoted herein, this apparent yield value is approximately
four times higher than
yield values calculated from shear rate and shear stress measurements in more
rigorous rheological
equipment. Apparent viscosities at high shear are determined with a Brookfield
RVT viscometer
with spindle #6 at 100 rpm, reading the torque at 30 seconds.
A preferred method herein for measuring viscosity and yield value is with a
Contraves
RheomatT~'' 115 viscometer which utilizes a Rheoscanr"'' 100 controller, a DIN
145 spindle and cup
at 25~C. For viscosity measurements, the shear rate is increased from 0 to l50
sec' over a 30
second time period. The viscosity, measured in centipoise, is taken at a shear
rate of l50 sec'.
The shear rate for yield value measurements is increased linearly from 0 to
0.4 sec' over a period
of 500 seconds after an initial 5 minute rest period.
pH Adiustin~ Agent
In the instant compositions, one or more buffering agents can be included
which are
capable of maintaining the pH of the compositions within the desired alkaline
range. The pH of the
undiluted composition ("as is") is determined at room temperature (about 20~C)
with a pH meter.
It is in the low alkaline pH range that optimum performance and stability of
the enzyme are
realized, and it is also within this pH range wherein optimum compositional,
chemical, and
physical stability are achieved.
WO 94I29428 PCTIUS94/06207 ."~".
~l~a~.~~ -~2-
Maintenance of the composition pH between about 7 and about 11, preferably
between
about 8 and about 10.5, minimizes undesirable degradation of the active
enzymes. Maintenance
of this particular pH range also maximizes the soil and stain removal
properties and prevents
spotting and filming during utilization of the present compositions.
The pH adjusting agents are generally present in a level from 0% to about 50%,
preferably
from about 8% to about 40% by weight of the detergent composition.
Any compatible material or mixture of materials which has the effect of
maintaining the
composition pH within the pH range of about 7 to about 11, preferably about 8
to about 10.5,
most preferably about 9 to 10.5, can be utilized as the pH adjusting agent in
the instant invention.
Such agents can include, for example, various water-soluble, inorganics salts
such as the
carbonates, bicarbonates, sesquicarbonates, tetraborates, hydroxides, and
mixtures thereof.
Silicates are not included because of their high alkaline buffering
properties.
Examples of preferred materials which can be used either alone or in
combination as the pH
adjusting agent herein include sodium carbonate, sodium bicarbonate, potassium
carbonate,
sodium sesquicarbonate, organic amines and their salts such as monoethanol
amine (MEA),
anhydrous sodium tetraborate, sodium tetraborate pentahydrate, potassium
hydroxide, sodium
hydroxide, and sodium tetraborate decahydrate. Combinations of these pH
adjusting agents,
which include both the sodium and potassium salts, may be used. As set forth
herein, the
compositions of the present invention comprise sufficient amount of both
potassium and sodium
ions. The pH adjusting can be a source for these ions.
Detergent Surfactants
The compositions of this invention can contain from 0% to about 20%,
preferably from
about 0.1 % to about 15%, more preferably from about 1 % to about 10% of a
detergent surfactant
which preferably results in a low foaming detergent composition. Preferably
the detergent
surfactant is low foaming or which in combination with other components (i. e.
suds suppressors)
is low foaming. Most preferably the surfactant is a low foaming nonionic
surfactant.
Because the composition is chlorine bleach free, there is no requirement that
the surfactant
be chlorine bleach stable. However, since enzymes are an essential ingredient
of the invention,
the surfactant employed is preferably enzyme stable (enzyme compatible) and
free of
enzymatically reactive species. For example, when proteases and amylases are
employed, the
surfactant should be free of peptide or glycosidic bonds. In addition, because
the composition is
phosphate free, compounds containing phosphorous should be avoided.
Desirable detergent surfactants include nonionic, anionic, amphoteric and
zwitterionic
detergent surfactants, and mixtures thereof.
13 ;~,
Examples of nonionic surfactants include:
( 1 ) The condensation product of 1 mole of a saturated or unsaturated,
straight or branched
chain, alcohol or fatty acid containing from about 10 to about 20 carbon atoms
with from about 4
to about 40 moles of ethylene oxide. Particularly preferred is the
condensation product of A fatty
alcohol containing from 17 to 19 carbon atoms, with from about 6 to about 1 S
moles, preferably 7
to 12 moles, most preferably 9 moles, of ethylene oxide provides superior
spotting and filming
performance. More particularly, it is desirable that the fatty alcohol contain
18 carbon atoms and
be condensed with from about 7.5 to about 12, preferably about 9 moles of
ethylene oxide. These
various specific C"C,9 ethoxylates give extremely good performance even at
lower levels (e.g.,
2.S%-3%). At the higher levels (less than S%), they are sufficiently low
sudsing, especially when
capped with a low molecular weight (C,_5) acid or alcohol moiety, so as to
minimize or eliminate
the need for a suds-suppressing agent. Suds-suppressing agents in general tend
to act as a load on
the composition and to hurt long term spotting and filming characteristics.
(2) Polyethylene glycols or polypropylene glycols having molecular weight of
from about
1,400 to about 30,000, e.g., 20,000; 9,S00; 7,S00; 7,S00; 6,000; 4,S00; 3,400;
and 1,450. All of
these materials are wax-like solids which melt between 110~F (43~C) and 200~F
(93~C).
(3) The condensation products of 1 mole of alkyl phenol wherein the alkyl
chain contains
from about 8 to about 18 carbon atoms and from about 4 to about SO moles of
ethylene oxide.
(4) Polyoxypropylene, polyoxyethylene condensates having the formula
HO(CZH60)X(C3H60)XH or HO(C3H6O)Y(CZH4O)X(C3H6O)yH where total y equals at
least 1 S and
total (CZH40) equals 20% to 90% of the total weight of the compound and the
molecular weight is
from about 2,000 to about 10,000, preferably from about 3,000 to about 6,000.
These materials
are, for example, the PLURONICS~ which are well known in the art.
(S) The compounds of (1) and (4) which are capped with propylene oxide,
butylene oxide
and/or short chain alcohols and/or short chain fatty acids, e.g., those
containing from 1 to about S
carbon atoms, and mixtures thereof.
Useful surfactants in detergent compositions are those having the formula
RO(CZH40)XR'
wherein R is an alkyl or allylene group containing from 17 to 19 carbon atoms,
x is a number
from about 6 to about 1 S, preferably from about 7 to about 12, and R' is
selected from the group
consisting of: preferably, hydrogen, C,_5 alkyl groups, C2_5 acyl groups and
groups having the
formula -(CyHZyO)"H wherein y is 3 or 4 and n is a number from one to about 4.
Particularly suitable surfactants are the low-sudsing compounds of (4), the
other
compounds of (S), and the C"-C,9 materials of (1) which have a narrow ethoxy
distribution.
Certain of the block co-polymer surfactant compounds designated PLURONIC,
PLURAFAC~ and
TETRONIC~ by the BASF Corp., Parsippany, N.J. are suitable as the surfactant
for use herein. A
particularly preferred embodiment contains a polyoxypropylene, polyoxyethylene
block polymer
B
-14_
blend comprising about 75%, by weight of the blend, of a reverse block co-
polymer of
polyoxyethylene and polyoxypropylene containing 17 moles of ethylene oxide and
44 mole of
propylene oxide; and about 25%, by weight of the blend, of a block co-polymer
of
polyoxyethylene and polyoxypropylene, initiated with tri-methylol propane,
containing 99 moles of
propylene oxide and 24 moles of ethylene oxide per mole of trimethylol
propane.
Additional nonionic type surfactants which may be employed have melting points
at or
above ambient temperatures, such as octyldimethylamine N-oxide dihydrate,
decyldimethylamine
N-oxide dihydrate, C$ C,Z N-methyl-glucamides and the like. Such surfactants
may advantageously
be blended in the instant compositions with short-chain anionic surfactants,
such as sodium octyl
sulfate and similar alkyl sulfates, though short-chain sulfonates such as
sodium cumene sulfonate
could also be used.
In addition to the above mentioned surfactants, other suitable surfactants for
detergent
compositions can be found in the disclosures of U.S. Patents 3,544,473,
3,630,923, 3,88,781 and
4,001, l32.
Anionic surfactants which are suitable for the compositions of the present
invention
include, but are not limited to, water soluble secondary alcohol sulfates, and
alkyl sulfates and/or
sulfonates, containing from about 6 to about 18 carbon atoms.
Natural fatty alcohols include those produced by reducing the glycerides of
naturally
occurring fats and oils. Fatty alcohols can be produced synthetically, for
example, by the Oxo
process. Examples of suitable alcohols which can be employed in alkyl sulfate
manufacture
include nonyl, undecyl, decyl, lauryl, tridecyl, myristyl, pentadecyl,
palmityl and stearyl alcohols
and the mixtures of fatty alcohols derived by reducing the glycerides of
tallow and coconut oil.
Specific examples of alkyl sulfate salts which can be employed in the instant
detergent
compositions include sodium lauryl alkyl sulfate, sodium stearyl alkyl
sulfate, sodium palmityl
alkyl sulfate, sodium decyl sulfate, sodium myristyl alkyl sulfate, potassium
lauryl alkyl sulfate,
potassium stearyl alkyl sulfate, potassium decyl sulfate, potassium palmityl
alkyl sulfate, potassium
myristyl alkyl sulfate, sodium dodecyl sulfate, potassium dodecyl sulfate,
potassium tallow alkyl
sulfate, sodium tallow alkyl sulfate, sodium coconut alkyl sulfate, magnesium
coconut alkyl sulfate,
calcium coconut alkyl sulfate, potassium coconut alkyl sulfate and mixtures
thereof. Highly
preferred alkyl sulfates are sodium coconut alkyl sulfate, potassium coconut
alkyl sulfate,
potassium lauryl alkyl sulfate and sodium lauryl alkyl sulfate.
A preferred sulfonated anionic surfactant is the alkali metal salt of
secondary alkane
sulfonates, an example of which is the HostapurTM SAS from Hoechst Celanese.
Another class of surfactants operable in the present invention are the water-
soluble betaine
surfactants. These materials have the general formula:
~.~'
-15-
R2
R1- N~+~___R4___COO~-~
R3
wherein R, is an alkyl group containing from about 8 to 22 carbon atoms; RZ
and R3 are each
lower alkyl groups containing from about 1 to 5 carbon atoms, and R4 is an
alkylene group
selected from the group consisting of methylene, propylene, butylene and
pentylene. (Propionate
betaines decompose in aqueous solution and hence are not included in the
instant compositions).
Examples of suitable betaine compounds of this type include
dodecyldimethylammonium
acetate, tetradecyldimethylammonium acetate, hexadecyldimethylammonium
acetate,
alkyldimethylammonium acetate wherein the alkyl group averages about 14.8
carbon atoms in
length, dodecyldimethylammonium butanoate, tetradecyldimethylammonium
butanoate,
hexadecyldimethylammonium butanoate, dodecyldimethylammonium hexanoate,
hexadecyldimethylammonium hexanoate, tetradecyldiethylammonium pentanoate and
tetradecyldipropylammonium pentanoate. Especially preferred betaine
surfactants include dodecyl
dimethylammonium acetate, dodecyldimethylammonium hexanoate,
hexadecyldimethylammonium
acetate, and hexadecyldimethylammonium hexanoate.
Other surfactants include amine oxides and sulfoxides. However, such
surfactants are
usually high sudsing. A disclosure of surfactants can be found in published
British Patent
Application 2,116,199A; U.S. Patent 4,005,027, Hartman; U.S. Patent 4,116,8S1,
Rupe et al; U.S.
Patent 3,985,668, Hartman; U.S. Patent 4,271,030, Brierley et al; and U.S.
Patent 4,116,849,
Leikhim.
Still other preferred anionic surfactants include the linear or branched
alkali metal mono-
and/or di-(C8_,4) alkyl diphenyl oxide nomo- and/or disulfonates, commercially
available under the
trade names DOWFAX~ 3B-2 (sodium n-decyl diphenyloxide disulfonate) and
DOWFAX~ 2A-1.
These and similar surfactants are disclosed in published U.K. Patent
Applications 2,163,447A;
2,163,448A; and 2,164,350A.
Chlorine Scavengers
In addition to the above listed enzyme stabilizers, from 0 to about 10%,
preferably from
about 0.01 % to about 6% by weight, of chlorine bleach scavengers can be added
to prevent
chlorine bleach species present in many water supplies from attacking and
deactivating 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 l.75 ppm, the available
chlorine in the total
volume of water that comes in contact with the enzyme during dishwashing is
usually large;
.~<
-16-
accordingly, enzyme stability in-use can be problematic.
Suitable chlorine scavenger anions for compositions of the present invention
with a pH less
than 8 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
carbamate, ascorbate. Other conventional scavenging anions like sulfate,
bisulfate, carbonate,
bicarbonate, percarbonate, nitrate, chloride, borate, sodium perborate
tetrahydrate, sodium perborate
monohydrate, acetate, benzoate, citrate, formate, lactate, malate, tartrate,
salicylate, organic amines
such as ethylenediaminetetracetic acid (EDTA) or alkali metal salt thereof and
monoethanolamine
(MEA), and mixtures thereof, preferably monoethanolamine, can also be used.
Some of the
above-described chlorine scavengers additionally serve as, detergency
builders, pH adjusting
agents, and/or bleaching agents.
Organic Dispersant
The present compositions can contain an organic dispersant which overcomes the
problem
of unsightly films and spots which form on china and especially on glassware
due to calcium or
magnesium hardness'induced precipitation of the builders and/or pH adjusting
agents (e.g.
especially carbonate).
The organic dispersants herein can be used at levels of 0 to about 40%,
typically from
about 0.5% to about 30%, most preferably from about 1 % to about 20% of the
automatic
dishwashing composition. Such organic dispersants are preferably water-soluble
sodium
polycarboxylates. ("Polycarboxylate" dispersants herein generally contain
truly polymeric numbers
of carboxylate groups, e.g., 8 or more, as distinct from carboxylate builders,
sometimes called
"polycarboxylates" in the art when, in fact, they have relatively low numbers
of carboxylate groups
such as four per molecule.) The organic dispersants are known for their
ability to disperse or
suspend calcium and magnesium "hardness", e.g., carbonate salts. Crystal
growth inhibition, e.g.,
of Ca/Mg carbonates, is another useful function of such materials. Preferably,
such organic
dispersants are polyacrylates or acrylate-containing copolymers. "Polymeric
Dispersing Agents,
SOKALAN", a printed publication of BASF Aktiengesellschaft, D-6700
Ludwigshaven, Germany,
describes organic dispersants useful herein. Preferred dispersants herein
described include, but are
not limited to sodium polyacrylate having a nominal molecular weight of about
4500, obtainable
from Rohm & Haas under the tradename ACUSOL~ (e.g. ACUSOL~ 445N), or
acrylate/maleate
copolymers such as are available under the tradename SOKALAN~, from BASF Corp.
These
polyanionic materials are, as noted, usually available as viscous aqueous
solutions, often having
dispersant concentrations of about 30-50%. The organic dispersant is most
commonly fully
neutralized; e.g., as the sodium salt form.
-17-
While the foregoing encompasses preferred organic dispersants for use herein,
it will be
appreciated that other oligomers and polymers of the general polycarboxylate
type can be used,
according to the desires of the formulator. Suitable polymers are generally
low molecular weight
and at least partially neutralized in the form of their alkali metal, ammonium
or other conventional
cation salts. The alkali metal, especially sodium salts, are most preferred.
While the molecular
weight of such dispersants can vary over a wide range, it preferably is from
about 1,000 to about
500,000, more preferably is from about 2,000 to about 250,000, and most
preferably is from about
3,000 to about l00,000. Nonlimiting examples of such materials are as follows.
For example, other suitable organic dispersants include those disclosed in
U.S. Patent
3,308,067 issued March 7, 1967, to Diehl. Unsaturated monomeric acids that can
be polymerized
to form suitable polymeric polycarboxylates include malefic acid (or malefic
anhydride), fumaric
acid, itaconic acid, aconitic acid, mesaconic acid, citraconic acid and
methylenemalonic acid. The
presence of monomeric segments containing no carboxylate radicals such as
vinylmethyl ether,
styrene, ethylene, etc. is suitable, preferably when such segments do not
constitute more than about
40% by weight of the polymer.
Other suitable organic dispersants for use herein are copolymers of acrylamide
and acrylate
having a molecular weight of from about 3,000 to about 100,000, preferably
from about 4,000 to
about 20,000, and an acrylamide content of less than about 50%, preferably
less than about 20%,
by weight of the polymer. Most preferably, the polymer has a molecular weight
of from about
4,000 to about l0,000 and an acrylamide content of from about 1% to about 15%,
by weight of
the polymer.
Still other useful organic dispersants include acrylate/maleate or
acrylate/fumarate
copolymers with an average molecular weight in acid form of from about 2,000
to about 80,000
and a ratio of acrylate to maleate or fumarate segments of from about 30:1 to
about 2:1. Other
such suitable copolymers based on a mixture of unsaturated mono- and
dicarboxylate monomers
are disclosed in European Patent Application No. 66,915, published December
15, l982. Yet other
organic dispersants are useful herein, as illustrated by water-soluble
oxidized carbohydrates, e.g.,
oxidized starches prepared by art-disclosed methods.
A particularly preferred embodiment of the present invention can contain from
0% to about
40%, preferably from about 1 % to about 30%, most preferably from about 1 % to
about 20%, by
weight of the automatic dishwashing detergent composition, of low molecular
weight modified
polyacrylate copolymers.
The term modified polyacrylate is defined as a copolymer which contains as
monomer
units: a) from about 90% to about 10%, preferably from about 80% to about 20%
by weight
acrylic acid or its salts and b) from about 10% to about 90%, preferably from
about 20% to about
80% by weight of a substituted acrylic monomer or its salts having the general
formula:
-18-
Rz R1
- [C =C ] -
C = O
O
R3
wherein at least one of the substituents R1, Rz or R3, preferably R, or Rz is
a 1 to 4 carbon alkyl or
hydroxyalkyl group, RI or Rz can be a hydrogen and R3 can be a hydrogen or
alkali metal salt.
Most preferred is a substituted acrylic monomer wherein R, is methyl, Rz is
hydrogen and R3 is
sodium.
The low molecular weight modified polyacrylate preferably has a molecular
weight of less
than about 1 S,000, preferably from about S00 to about 10,000, most preferably
from about 1,000
to about 5,000. The most preferred polyacrylate copolymer has a molecular
weight of about 3500
and is about 70% by weight acrylic acid and about 30% by weight methyl acrylic
acid.
Suitable modified polyacrylate copolymers include the low molecular weight
copolymers of
unsaturated aliphatic carboxylic acids as disclosed in U.S. Patent 4,S30,766,
and 5,084,S3S.
Other Optional Ingredients
Metal salts of long chain fatty acids and/or long chain hydroxy fatty acids
have been found
to be useful in automatic dishwashing detergent compositions to inhibit
tarnishing caused by
repeated exposure of sterling or silver-plate flatware to bleach-containing
automatic dishwashing
detergent compositions (U.S. Patent 4,8S9,3S8, Gabriel et al). By "long chain"
is meant the higher
aliphatic fatty acids or hydroxy fatty acids having from about 6 to about 24
carbon atoms,
preferably from about 8 to 22 carbon atoms, and most preferably from about 10
to 20 carbon
atoms and most preferably from about 12 to 18, inclusive of the carbon atom of
carboxyl group of
the fatty acid, e.g., stearic acid, and hydroxy stearic acid. By "metal salts"
of the long chain fatty
acids and/or hydroxy fatty acids is meant both monovalent and polyvalent metal
salts, particularly
the sodium, potassium, lithium, aluminum, and zinc salts, e.g., lithium salts
of the fatty acids.
Specific examples of this material are aluminum, potassium, sodium, calcium
and lithium stearate
or hydroxy stearate, particularly preferred is aluminum tristearate. If the
metal salts of long chain
hydroxy fatty acids are incorporated into the automatic dishwashing detergent
compositions of the
present invention, this component generally comprises from 0% to about 2%,
preferably from
about 0.0S% to about 0.2% by weight of the composition.
-19-
An alkali metal salt of an amphoteric metal salt of an amphoteric metal anion
(metalate),
such as aluminate, can be added to provide additional structuring to the
polycarboxylate polymer
thickening agent. See U. S. Patent 4,94l,988, Wise, issued July 17, 1990.
Compounds known, or which become known, for reducing or suppressing the
formation of
suds can be incorporated into the compositions of the present invention. The
compositions hereof
will generally comprise from 0% to about 5% of suds suppressor.
Suitable suds suppressors are described in Kirk-Othmer Encyclopedia of
Chemical
Technology, Third Edition, Volume 7, pages 430-447 (John Wiley & Sons, Inc.,
1979), U.S.
Patent 2,954,347, issued September 27, 1960 to St. John, U.S. Patent
4,265,779, issued May 5,
1981 to Gandolfo et al., and European Patent Application No. 354,0l6,
published February 7,
1990, U.S. Patent 3,455,839, German Patent Application DOS 2,124,526, U.S.
Patent 3,933,672,
Bartolatta et al and U.S. Patent 4,652,392, Baginski. A commercially
acceptable suds suppressor is
LPKN, from Knapsack.
Suitable nonchlorine bleaches in the present compositions are solid, water-
soluble
peroxygen compounds in levels from 0 to about 15%, preferably from about 0.2%
to about 12%
by weight of the composition. The peroxygen compound can be a preformed
peroxyacid, an
inorganic persalt or a combination of an inorganic per salt and an inorganic
precursor (i.e. bleach
activator).
Examples of suitable organic peroxyacids are disclosed in U.S. Patents
4,374,03S, Bossu,
issued Feb. 15, l983; 4,68l,592, Hardy et al, issued July 21, l987; 4,634,551,
Burns et al, issued
Jan. 6, 1987; 4,686,063, Burns, issued Aug. 11, l987; 4,606,838, Burns, issued
Aug. 19, 1986; and
4,67l,891, Hartman, issued June 9, l987. Examples of compositions which
contain perborate
bleaches and activators therefore are disclosed in U.S. Patent 4,412,934,
Chung and Spadini, issued
Nov. l, l983; 4,536,314, Hardy et al, issued Aug. 20, 1985; 4,681,695, Divo,
issued July 21,
l987; and 4,539,120, Thompson et al, issued Sept. 3, 1985.
Preferred compositions of the invention contain peroxygen compounds such as
perborates,
persulfates, percarbonates, peroxydisulfates, crystalline peroxyhydrates and
mixtures thereof.
Liquid detergent compositions can contain water and other solvents as
carriers. These
WO 94/29428 PCT/US94/06207
-20-
solvents include, but are not limited to, low molecular weight primary or
secondary alcohols
exemplified by methanol, ethanol, propanol, and isopropanol. Monohydric
alcohols are preferred
for solubilizing surfactant, but polyols such as those containing from 2 to
about 6 carbon atoms
and from 2 to about 6 hydroxy groups (e.g., propylene glycol, ethylene glycol,
glycerine, and 1,2-
propanediol) can also be used.
Other solvents include the higher glycols, polyoxides, glycol ethers,
propylene glycol ehters
and tripropylene glycol ethers. Any water used in the composition should
preferably be softened
or deionized.
A wide variety of other ingredients useful in detergent compositions can be
included in the
compositions hereof, including other active ingredients, carriers,
hydrotropes, draining promoting
agents, processing aids, corrosion inhibitors, perfumes, dyes or pigments,
etc.
If present, the above-described other optional materials generally are enzyme
compatible
and are dissolved, suspended, or emulsified in the present compositions.
Composition .
Preferred viscoeleastic, thixotropic, liquid automatic dishwashing detergent
compositions
hereof will preferably be formulated such that during use in aqueous
operations, the wash water
will have a pH of between about 7 and 11, preferably between about 8 and 10.5.
This invention further provides a method for cleaning dishware (i.e. glass,
china, flatware,
silverware and the like) by contacting the dishware with a liquid detergent
composition
comprising detersive enzyme, detersive surfactant, viscoelastic thixotropic
thickening agent,
enzyme stabilizing system, and buffering agent. Agitation is preferably
provided for enhanced
cleaning.
Preferred herein are concentrated gel and/or paste automatic dishwashing
detergent
compositions, more preferably gel automatic dishwashing detergent
compositions. By
"concentrated" or "compact" is meant that these compositions will deliver to
the wash the same
amount of active detersive ingredients at a lower dosage while achieving equal
or improved
performance. For example, in North America, dishwasher machines range in total
dispenser cup
capacity (many dishwashers have several dispenser cups) from about 80 cc to
about 1 SO cc of
product, depending on the machine manufacturer. Most current automatic
dishwashing products
are formulated to deliver the desired performance based on this dispensing
volume. Compact
products allow the reduction in the amount of product used to between 40% and
60%, but can
range from about 1% to about 99%.
Process
Conventional methods can be used to prepare the viscoelastic, thixotropic
liquid automatic
dishwashing detergent compositions herein described. See, for example, U.S.
Patents 4,824,590,
WO 94I29428 J PCT/US94106207
,u~,...
-21 -
Roselle, issued April 25, 1989; 5,053,158, Dixit et al, issued October 1,
1991, 4,970,016, Ahmed
et al, issued November 13, 1990, 5,057,237, Drapier et al, issued October 15,
1991 and
5,078,027, Dixit et al, issued December 24, 1991. A preferred method for
preparing a final
product of the present invention comprises:
(a) mixing water, enzyme stabilizers and pH adjusting agents under low to
medium shear
rate;
(b) adding organic dispersant and builder;
(c) adding under medium shearing a thickener slurry until a desired
rheological property is
achieved;
(d) adding surfactant and other suitable agents; and
(e) adding enzymes.
An alternate method is similar to the method herein above; however, the
thickener is added
after step (d) (adding surfactant and other suitable agents) and before the
addition of enzymes.
The thickener may be added as either a powder or slurry.
Whichever method is employed, the enzyme stabilizing system should be added
prior to the
addition of builder. Without being bound by theory, it is believed the enzyme
stabilizing system
added after the builder will associate with the builder and Lose its
effectiveness; whereas, if added
prior to the builder it will form an effective compound which will not
associate with the builder.
In addition, enzymes should be added last to minimize degradation due to
temperature and
pH changes resulting during the process.
All compositions prepared as above described exhibit a viscoelastic,
thixotropic nature, and
have good phase stability.
The following examples illustrate the compositions of the present invention.
All parts,
percentages and ratios used herein are by stock weight unless otherwise
specified.
EXAMPLE I
Concentrated gel automatic dishwashing detergent compositions of the present
invention
prepared according to the above described process are as follows:
WO 94/29428 PCT/US94/06207
..r
Table 1
by weight
Ing,.,redients A B C D E F G
Potassium carbonate 2.00 4.00 0.00 9.73 3.50 0.00 0.2S
Sodium carbonate 13.47 S.43 0.00 12.42 3.74 0.00 S.00
Sodium citrate 0.00 1S.00 2S.00 0.00 0.00 0.00 0.00
dihydrate
Potassium hydroxide 0.00 0.00 4.98 0.00 8.44 17.78 0.67
(4S%)
Sodium hydroxide 0.00 0.00 0.00 0.00 3.00 7.72 0.00
(SO%)
Citric acid (SO%) 0.00 0.00 0.00 0.0D 19.70 34.S8 1.10
Monoethanolamine 1.91 l.91 l.91 1.91 1.91 1.91 1.91
PolyaCrylate thick- 2.00 2.00 2.00 1.7S 2.00 2.00 2.00
ene ( i lr
Perfume 0.10 0.10 0.10 0.10 0.10 0.10 0.10
Dye 0.002 0.002 0.002 0.002 0.002 0.002 0.002
Sodium~~lyacrylate 20.00 11.33 8.89 11.93 9.6S 0.00 19.80
(45%)
Polyoxypropylene- 2.50 2.S0 2.50 2.S0 2.S0 2.S0 2.50
polyoxyethylene (3)
block copolymer
Boric acid 2.00 2.00 2.00 2.00 2.00 2.00 2.00
1,2-propanediol 4 4.50 4.S0 4.S0 4.S0 4.S0 4.S0 4.S0
Protease enzyme~s~ 0.42 0.42 0.42 0.42 0.42 0.42 0.42
Amylase enzyme 0.42 0.42 0.42 0:42 0.42 0.42 0.42
Water and trim balance
pH ,10 ,10 ,10 ,10 ,10 ,10 ,10
K/Na ratio 0.20 0.2S 0.33 1.04 0:83 0.92 0.07
~2~Polygel DK, 3-V Chemical Corporation
Acusol 44SN or Acusol 480N, Rohm and Haas, Incorporated
~4~Pluronic~ 25R2, BASF Corporation
(S)Savmase ~32.0 L EX, Novo Nordisk Industries, Incorporated
Maxamyl WL 15;000, Gist-Brocades USA Incorporated
WO 94/29428 t ~ PCT/LTS94I06207
-23-
EXAMPLE II
Other concentrated
gel detergent products
are as follows:
Table 2
by
Weisht
Ingredients H I J K L
Potassium carbonate 0.00 7.50 4.00 4.00 4.00
' Sodium carbonate 0.00 7.50 5.43 5.43 5.43
Sodium citrate 0.00 0.00 15.00 15.00 15.00
dihydrate
Potassium hydroxide 8.00 0.00 0.00 0.00 0.00
(45%)
Sodium hydroxide 5.97 0.00 0.00 0.00 0.00
(50%)
Citric acid (50%) 38.570.00 0.00 0.00 0.00
Monoethanolamine 1.91 20.00 0.00 1.91 l.91
Aluminum tristearate 0.00 0.00 0.10 0.10 0.10
Polyarrylate thick- 1.70 2.00 2.00 2.00 2.00
(1l
ene
r
Perfume 0.05 0.05 0.10 0.10 0.10 Dye 0.000 0.000
0.002 0.002 0.002
Sodium~~ lyacrylate 8.89 10.00 11.30 11.30 11.30
(45%)
Polyoxypropylene- 2 .S0 0.00 2.50 2.50 2.50
polyoxyethylene
(3)
block copolyme4
( )
Suds suppressor 0.00 0.00 0.00 1.00 0.00
Boric acid 1. 95 .95 2.00 2.00 2.00
1
Sodium formate 0.00 0.00 0.00 0.00 0.20
Calcium formate 0.00 0.00 0.00 0.00 0.45
Sodium cumene sulfonate
1.35 0.00 0.00 0.00
0.00
1,2-propanediol 4.50 4.50 4.50 4.50 4.50
( )
Protease enzyme 0.42 0.42 0.42 0.42 0.42
6)
Amylase enzy 0.22 0.22 0.42 0.42 0.42
~~
~
Lipase enzyme 0.00 0.00 0.00 0.30 0.30
."- WO 94I29428 PCT/US94/06207
-24-
Water and trim ------------------balance-------------------
pH ,8 ,10 ,10 ,10 ,10
Finished product
K/Na ratio 0.54 1.33 .25 .25 .25
~ 1 ~Pblygel DK, 3-V Chemical Corporation
~3~Acusol 445N or Acusol 480N, Rohm and Haas, Incorporated
l4 Pluronic~ 25R2, BASF Corporation
~S~LPKN, ~apsack
6 Savinase 32.0 L EX, Novo Nordisk Industries, Incorporated
~,~~Maxamyl~ WL I5,000, Gist-Brocades USA Incorporated
Lipolase I00L Novo-Nordisk
B~
