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Description  |
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TECHNICAL FIELD
This invention is in the field of liquid and granular automatic dishwashing
compositions. More specifically, the invention relates to compositions
containing silicate and low molecular weight modified polyacrylate
copolymers.
BACKGROUND OF THE INVENTION
Liquid and granular automatic dishwashing detergent components while
necessary for various cleaning benefits, often can create other problems.
For example, carbonate, and phosphate, conventional detergent ingredients,
are known to contribute to formation of hard water film on glasses.
Organic dispersants can overcome the problem of unsightly films which form
on china, especially on glassware, due to calcium- or magnesium-hardness-
induced precipitation of pH-adjusting agents. However not all dispersants
work as well on the various types of precipitation.
Although conventional low molecular weight polyacrylate homopolymers are
satisfactory in the dispersion of insoluble calcium carbonate in automatic
dishwashing detergent compositions, it has recently been found that low
molecular weight modified polyacrylate copolymers enhance filming
performance in automatic dishwashing detergent compositions containing
silicate.
Not only do the low molecular weight modified polyacrylate copolymers of
the present invention prevent hard water filming due to precipitation of
silicate but it has also been surprisingly found that these modified
polyacrylates show improved enzyme performance (i.e. bulk food removal) in
enzyme containing automatic dishwashing detergent compositions.
SUMMARY OF THE INVENTION
The present invention encompasses a liquid or granular automatic
dishwashing detergent composition comprising:
(a) from about 0.01% to about 40% alkali metal silicate; and
(b) from about 0.1% to about 20% modified polyacrylate copolymer having a
molecular weight of less than about 15,000.
A preferred liquid or granular automatic dishwashing detergent composition
herein comprises enzyme and/or carbonate.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is a liquid or granular automatic dishwashing
detergent composition comprising:
(a) from about 0.01% to about 90% detergency builder;
(b) from about 0.1% to about 20% modified polyacrylate copolymer having a
molecular weight less than about 15,000; and
(c) from about 0.001% to about 5% detersive enzyme.
Compositions of the invention exhibit enhanced hard water filming
performance and improved enzyme performance by the presence of low
molecular weight modified polyacrylates.
SILICATE
The compositions of the type described herein deliver their bleach and
alkalinity to the wash water very quickly. Accordingly, they can be
aggressive to metals, dishware, and other materials, which can result in
either discoloration by etching, chemical reaction, etc. or weight loss.
The alkali metal silicates hereinafter described provide protection
against corrosion of metals and against attack on dishware, including fine
china and glassware.
The SiO.sub.2 level in the composition of the present invention should be
from about 0.01% to about 40%, preferably 4% to about 25%, more preferably
from about 5% to about 20%, most preferably from about 6% to about 15%,
based on the weight of the automatic dishwashing detergent composition.
The ratio of SiO.sub.2 to the alkali metal oxide (M.sup.2 O, where
M=alkali metal) is typically from about 1 to about 3.2, preferably from
about 1.6 to about 3, more preferably from about 2 to about 2.4.
Preferably, the alkali metal silicate is hydrous, having from about 15% to
about 25% water, more preferably, from about 17% to about 20%.
The highly alkaline metasilicates can be employed, although the less
alkaline hydrous alkali metal silicates having a SiO.sub.2 :M.sub.2 O
ratio of from about 2.0 to about 2.4 are preferred. Anhydrous forms of the
alkali metal silicates with a SiO.sub.2 :M.sub.2 O ratio of 2.0 or more
are less preferred because they tend to be significantly less soluble than
the hydrous alkali metal silicates having the same ratio.
Sodium and potassium, and especially sodium, silicates are preferred. A
particularly preferred alkali metal silicate is a granular hydrous sodium
silicate having a SiO.sub.2 :Na.sub.2 O ratio of from 2.0 to 2.4 available
from PQ Corporation, named Britesil H.sub.2 O and Britesil H24. Most
preferred is a granular hydrous sodium silicate having a SiO.sub.2
:Na.sub.2 O ratio of 2.0.
While typical forms, i.e. powder and granular, of hydrous silicate
particles are suitable, preferred silicate particles have a mean particle
size between about 300 and about 900 microns with less than 40% smaller
than 150 microns and less than 5% larger than 1700 microns. Particularly
preferred is a silicate particle with a mean particle size between about
400 and about 700 microns with less than 20% smaller than 150 microns and
less than 1% larger than 1700 microns.
LOW MOLECULAR WEIGHT MODIFIED POLYACRYLATES
The present invention can contain from about 0.1% to about 20%, preferably
from about 1% to about 10%, most preferably from about 3% to about 8%, by
weight of the automatic dishwashing detergent composition, of low
molecular weight modified polyacrylate copolymer.
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:
##STR1##
wherein at least one of the substituents R.sub.1, R.sub.2 or R.sub.3,
preferably R.sub.1 or R.sub.2 is a 1 to 4 carbon alkyl or hydroxyalkyl
group; R.sub.1 or R.sub.2 can be a hydrogen and R.sub.3 can be a hydrogen
or alkali metal salt. Most preferred is a substituted acrylic monomer
wherein R.sub.1 is methyl, R.sub.2 is hydrogen and R.sub.3 is sodium.
The low molecular weight polyacrylate preferably has a molecular weight of
less than about 15,000, preferably from about 500 to about 10,000, most
preferably from about 1,000 to about 5,000. The most preferred modified
polyacrylate copolymer has a molecular weight of 3500 and is about 70% by
weight acrylic acid and about 30% by weight methyl acrylic acid.
Suitable modified polyacrylates include the low molecular weight copolymers
of unsaturated aliphatic carboxylic acids as disclosed in U.S. Pat. Nos.
4,530,766, and 5,084,535, both of which are incorporated herein by
reference.
DETERGENCY BUILDER
The detergency builders used can be any of the detergency builders known in
the art, which include the various water-soluble, alkali metal, ammonium
or substituted ammonium phosphates, polyphosphates, phosphonates,
polyphosphonates, carbonates, bicarbonates, borates,
polyhydroxysulfonates, polyacetates, carboxylates (e.g. citrates), and
polycarboxylates. Preferred are the alkali metal, especially sodium, salts
of the above and mixtures thereof.
The amount of builder is from about 0.01% to about 90%, preferably from
about 15% to about 80%, most preferably from about 15% to about 75% by
weight of the automatic dishwashing detergent composition.
Specific examples of inorganic phosphate builders are sodium and potassium
tripolyphosphate, pyrophosphate, polymeric metaphosphate having a degree
of polymerization of from about 6 to 21, and orthophosphate. Examples of
polyphosphonate builders are the sodium and potassium salts of ethylene
diphosphonic acid, the sodium and potassium salts of ethane 1-hydroxy-1,
1-diphosphonic acid and the sodium and potassium salts of ethane,
1,1,2-triphosphonic acid. A particularly preferred polyphosphonate builder
component is ethane 1-hydroxy-1, 1 diphosphonic acid or its alkali metal
salts, which demonstrates calcium carbonate crystal growth inhibition
properties, present at a level of from about 0.01% to about 20%,
preferably from about 0.1% to about 10%, most preferably from about 0.2%
to about 5% by weight of the compositions. Other phosphorus builder
compounds are disclosed in U.S. Pat. Nos. 3,159,581; 3,213,030; 3,422,021;
3,422,137, 3,400,176 and 3,400,148, incorporated herein by reference.
Examples of non-phosphorus, inorganic builders are sodium and potassium
carbonate, bicarbonate, sesquicarbonate and hydroxide.
Water-soluble, non-phosphorus organic builders useful herein include the
various alkali metal, ammonium and substituted ammonium polyacetates,
carboxylates, 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. The
acidic form of these builders can also be used, preferably 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. Sodium
tripolyphosphate is typically a particularly preferred detergency builder
material because of its sequestering ability. Sodium citrate is also a
particularly preferred detergency builder, particularly when it is
desirable to reduce or eliminate the total phosphorus level of the
compositions of the invention.
Particularly preferred automatic dishwashing detergent compositions of the
invention contain, by weight of the automatic dishwashing detergent
composition, from about 5% to about 40%, preferably from about 10% to
about 30%, most preferably from about 15% to about 20%, of sodium
carbonate. Particularly preferred as a replacement for the phosphate
builder is sodium citrate with levels from about 5% to about 40%,
preferably from about 7% to 35%, most preferably from about 8% to about
30%, by weight of the automatic dishwashing detergent composition.
Some of the above-described detergency builders additionally serve as
buffering agents. It is preferred that the buffering agent contain at
least one compound capable of additionally acting as a builder.
DETERSIVE ENZYME
The compositions of this invention may contain from about 0.001% to about
5%, more preferably from about 0.003% to about 4%, most preferably from
about 0.005% to about 3%, by weight, of active detersive enzyme.
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 licheniformis.
Suitable proteolytic enzymes include Alcalase.RTM., Esperase.RTM.,
Durazym.RTM., Savinase.RTM. (preferred); Maxatase.RTM., Maxacal.RTM.
(preferred), and Maxapem.RTM. 15 (protein engineered Maxacal);
Purafect.RTM. (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 Serial Number 87 303761.8, filed Apr. 28, 1987 (particularly
pages 17, 24 and 98), and which is called herein "Protease B", and in
European Patent Application 199,404, Venegas, published Oct. 29, 1986,
which refers to a modified bacterial serine proteolytic enzyme which is
called "Protease A" herein. Preferred proteolytic enzymes, then, are
selected from the group consisting of Savinase.RTM., Esperase.RTM.,
Maxacal.RTM., Purafect.RTM., BPN', Protease A and Protease B, and mixtures
thereof. Savinase.RTM. 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 19.154, as disclosed in British Patent
1,372,034, incorporated herein by reference. Suitable lipases include
those which show a positive immunological cross-reaction with the antibody
of the lipase produced from the microorganism Pseudomonas fluorescens IAM
1057. This lipase and a method for its purification have been described in
Japanese Patent Application 53-20487, laid open on Feb. 24, 1978, which is
incorporated herein by reference. This lipase is available under the trade
name Lipas 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 (1950)).
These lipases, and a method for their immunological cross-reaction with
Amano-P, are also described in U.S. Pat. No. 4,707,291, Thom et al.,
issued Nov. 17, 1987, incorporated herein by reference. Typical examples
thereof are the Amano-P lipase, the lipase ex Pseudomonas fragi FERM P
1339 (available under the trade name Amano-B), lipase ex Pseudomonas
nitroreducens var. lipolyticum FERM P 1338 (available under the trade name
Amano-CES), lipases ex Chromobacter viscosum var. lipolyticum NRR1b 3673,
and further Chromobacter viscousm lipases, and lipases ex Pseudomonas
gladioli. A preferred lipase is derived from Pseudomonas
pseudoalcaligenes, 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 lipases which are of interest where they are compatible with the
composition are those described in EP A 0 339 681, published Nov. 28,
1990, EP A 0 385 401, published Sep. 5, 1990, EP A 0 218 272, published
Apr. 15, 1987, and PCT/DK 88/00177, published May 18, 1989, all
incorporated herein by reference.
Suitable fungal lipases include those produced by Humicola lanuginosa and
Thermomyces lanuginosus. Most preferred is lipase obtained by cloning the
gene from Humicola lanuginosa and expressing the gene in Aspergillus
oryzae as described in European Patent Application 0 258 068, incorporated
herein by reference, commercially available under the trade name
Lipolase.RTM. from Novo-Nordisk.
Any amylase suitable for use in a dishwashing detergent composition can be
used in these compositions. Amylases include for example, .alpha.-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, Rapidase.TM., Maxamyl.TM., Termamyl.TM. and BAN.TM..
In a preferred embodiment, from about 0.001% to about 5%, preferably 0.005%
to about 3%, by weight of active amylase can be used. Preferably from
about 0.005% to about 3% by weight of active protease can be used.
Preferably the amylase is Maxamyl.TM. and/or Termamyl.TM. and the protease
is Savinase.RTM. and/or protease B.
DETERGENT SURFACTANTS
The compositions of this invention can contain from about 0.01% to about
40%, preferably from about 0.1% to about 30% of a detergent surfactant. In
the preferred automatic dishwashing detergent compositions of the
invention the detergent surfactant is most preferably low foaming by
itself or in combination with other components (i.e. suds suppressors) is
low foaming.
Compositions which are chlorine bleach free do not require the surfactant
to be bleach stable. Similarly, those compositions containing enzymes, 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.
Desirable detergent surfactants include nonionic, anionic, amphoteric and
zwitterionic detergent surfactants, and mixtures thereof.
Examples of nonionic surfactants include:
(1) The condensation product of 1 mole of a saturated or unsaturated,
straight or branched chain, alcohol of 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
15 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.sub.17 -C.sub.19
ethoxylates give extremely good performance even at lower levels (e.g.,
2.5%-3%). At the higher levels (less than 5%), they are sufficiently low
sudsing, especially when capped with a low molecular weight (C.sub.1-5)
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; 9,500; 7,500; 7,500;
6,000; 4,500; 3,400; and 1,450. All of these materials are wax-like solids
which melt between 110.degree. F. (43.degree. C.) and 200.degree. F.
(93.degree. 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 50 moles of ethylene oxide.
(4) Polyoxypropylene, polyoxyethylene condensates having the to formula
HO(C.sub.2 H.sub.6 O).sub.x (C.sub.3 H.sub.6 O).sub.x H or HO(C.sub.3
H.sub.6 O).sub.y (C.sub.2 H.sub.4 O).sub.x (C.sub.3 H.sub.6 O).sub.y H
where total y equals at least 15 and total (C.sub.2 H.sub.4 O) 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.RTM. from BASF
which are well known in the art.
(5) 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 5 carbon atoms, and mixtures
thereof.
Useful surfactants in detergent compositions are those having the formula
RO-(C.sub.2 H.sub.4 O).sub.x R.sup.1 wherein R is an alkyl or alkylene
group containing from 17 to 19 carbon atoms, x is a number from about 6 to
about 15, preferably from about 7 to about 12, and R.sup.1 is selected
from the group consisting of: hydrogen, C.sub.1-5 alkyl groups, C.sub.2-5
acyl groups and groups having the formula --(C.sub.y H.sub.2y O).sub.n 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 (5), and the C.sub.17 -C.sub.19 materials of (1) which
have a narrow ethoxy distribution. Certain of the block co-polymer
surfactant compounds designated PLURONIC.RTM., PLURAFAC.RTM. and
TETRONIC.RTM. by the BASF Corp., Parsippany, N.J. are suitable as the
surfactant for use herein. A particularly preferred embodiment contains
from about 40% to about 70% of a polyoxypropylene, polyoxethylene block
polymer 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 moles 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.sub.8 -C.sub.12
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. Pat.
Nos. 3,544,473, 3,630,923, 3,88,781, 4,001,132, and 4,375,565 all of which
are incorporated herein by reference.
Anionic surfactants which are suitable for the compositions of the present
invention include, but are not limited to, water soluble-alkyl sulfates
and/or sulfonates, containing from about 8 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 decyl,
lauryl, myristyl, 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 Hostapur 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:
##STR2##
R.sub.1 is an alkyl group containing from about 8 to 22 carbon atoms;
R.sub.2 and R.sub.3 are each lower alkyl groups containing from about 1 to
5 carbon atoms, and R.sub.4 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
liquid compositions of the instant invention).
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 dodecyldimethylammonium acetate,
dodecyldimethylammonium hexanoate, hexadecyldimethylammonium acetate, and
hexadecyldimethylammonium hexanoate.
Other surfactants include amine oxides, phosphine 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. Pat. No. 4,005,027, Hartman; U.S. Pat. No. 4,116,851,
Rupe et al; U.S. Pat. No. 3,985,668, Hartman; U.S. Pat. No. 4,271,030,
Brierley et al; and U.S. Pat. No. 4,116,849, Leikhim, all of which are
incorporated herein by reference.
Other desirable surfactants are the alkyl phosphonates, taught in U.S. Pat.
No. 4,105,573 to Jacobsen issued Aug. 8, 1978, incorporated herein by
reference.
Still other preferred anionic surfactants include the linear or branched
alkali metal mono- and/or di-(C.sub.8-14) alkyl diphenyl oxide | | |
