Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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A PERACID BASED DISH~PASIiING DETERGENT COMPOSITION
Field of the Invention
The invention relates to a low alkalinity dishwashing
detergent composition containing a peracid, a bleach
resistant amylase and a builder. A method of using the
composition is also described.
Baokqrouad of the Invention
Many conventional dishwashing systems use high alkalinity
cleaning compositions which may include chlorine bleach as
sanitizer. Whilst these systems are highly effective with
regard to the removal of hydrophilic and bleachable stains
from dishware, they have an inherent weakness with respect to
the removal of starch-containing food soils. Incomplete
removal of starch in successive washes leads to a gradual
build-up of soil so that after only one to two weeks of
cleaning with these systems the appearance of the dishware
can become unacceptable. At this point, extensive soaking of
the dishware may be required which is a separate operation
that is laborious, time-consuming, and very expensive. Such
build up problems are especially pronounced in industrial and
institutional warewashing where foods and dishware are
subject to high temperatures for prolonged periods of time
during food preparation, distribution and serving.
Amylase enzymes have been proposed as a solution to the
problem of starch build-up on cleaned dishware. However,
' 30 amylases are less effective at wash pHs greater than 10 (see
GB-A-1 296 839 (Novo)), and are incompatible with chlorine
bleach. As a consequence, trends in formulating dishwashing
compositions with amylase have been toward the use of
peroxygen bleaching agents in lieu of halogen bleach sources.
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Because oxygen bleaching systems tend to be less effective
than chlorine on tannin stains, those cleaning systems that
use amylase enzymes and which have been proposed to date,
provide only moderate levels of removal of bleachable stains
such as tannin. Indeed, no single system that has been
proposed to date can effectively meet the requirements of
excellent starch and tannin removal.
Bleach resistant amylase enzymes described in the art may be
incorporated with either halogen or peroxygen bleaches in a
detergent composition, as described in WO-94/02597 {Novo);
EP-A-208,491 {Genencor) and WO-94/14951 (Novo). Although
such systems should deliver both excellent starch and tannin
removal, it has been observed that the mere replacement of
standard enzymes with the bleach-resistant varieties in
conventional formulations results in poorer, rather than
improved, overall performance. A need still exists for
stable compositions which deliver effective performance over
a full range of soils and stains.
Cleaning systems which deliver both excellent starch and
tannin removal have now been discovered. It has been found
that selected oxygen bleaches formulated in a non-
conventional pH range can meet these demanding performance
targets. In addition, surprising synergistic interactions
between certain bleaches, bleach resistant enzymes, builders
and wash conditions have actually been found to enhance
enzyme activity and improve enzyme stability to provide
cleaning systems which deliver excellent performance over a
full range of soils and stains.
Swaataxw of the Invention
A warewashing detergent composition for use in both domestic
and industrial dishwashing machines is described. The
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composition comprises an organic monoperoxy or diperoxy acid which
exhibits maximum tannin stain removal efficacy at a wash pH of about 8.5
which is at or near the pKa of the peroxy acid the organic peroxy acid being
present in an amount of 1 ppm to 100 ppm available 02 in the solution;
an amylase enzyme which, when incubated at 55° C in a solution of 2 mM
sodium citrate, 1 mM epsilon phthalimidoperoxyhexanoic acid in 36 ppm
water at pH 8.0, has a half life of 10 minutes or greater based on an activity
vs. time plot obtained via monitoring color development at 405 nm of solution
samples incubated with p-nitrophenyl-a-D-maltoheptaoside as substrate and
gluco amylase and a-glucosidase as coupled enzymes; and 1 % by weight to
75% by weight of a builder, provided that a 1 % aqueous solution of the
warewashing composition has a pH of 6 to 9.5.
Detailed description of the Preferred Embodiments
The compositions of the invention may be in any form known in the art such
as powder, tablet, block, liquid or gel. The compositions may also be
produced by any conventional means.
Novel combinations of cleaning agents have been identified that will satisfy
the demand for excellent starch and tannin removal from a single wash
system. This system comprises an effective amount of a suitable organic
peroxy acid, an effective amount of an amylase enzyme which, when
incubated at 55°C in a solution of 2mM sodium citrate, 1 mM epsilon
phthalimidoperoxyhexanoic acid in 36 ppm water at pH 8.0, has a half-life of
two minutes or greater based on an activity vs. time plot obtained via
monitoring samples on a Roche Cobas Fara AnalyzerT'", using Roche
ReagentT"", and about 1 to about 75 wt% of a builder, provided that a 1
aqueous solution of the detergent composition has a pH of from 6 to 9.
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~erox~ Acids .
Since amylase enzymes are ineffective in a wash pH range of
greater than about 10, it is necessary to be able to achieve
good bleach performance in a wash having a pH value of less
than about 10 in order to meet the dual criteria of excellent
starch and excellent tannin removal.
It is also desirable to replace a halogen bleach with a
peroxygen bleach to provide a milder and more environmentally
friendly composition.
Typically, formulations based on oxygen bleaches include
sodium perborate, sodium percarbonate or hydrogen peroxide.
These oxygen bleaches are preferably used in conjunction with
a bleach activator to provide more effective bleaching at
15 temperatures of below about 60°C.
However, in the present invention, selection of the bleach
moiety is critical. Despite claims that the bleach-resistant
amylases are functional with a full range of bleaches,
20 excellent overall performance is not achieved with this
range.
Thus, the bleaching performance of hydrogen peroxide (Ha02)
decreases as the pH of the wash is reduced from about 12 to
about 10. At pH 10, in short wash times, inclusion of H20a
provides.no extra tannin removal benefits than could be
obtained through the utilization of a strong builder such as
nitrilotriacetate. Therefore, there is no advantage for a
bleach-resistant amylase with hydrogen peroxide. In fact, at
pH 10, the combination of Hz02/conventional amylase is more
effective with regard to starch removal than the combination
of H202/bleach-resistant amylase.
Peroxide/activator systems generally require a wash pH of
about 10 in order to achieve rapid rates of perhydrolysis,
~ -.
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something that would be essential at short wash times.
However, this requirement conflicts with the optimum
conditions for starch removal since the activity of the novel
bleach-resistant amylase is very low at wash pH's of about 10
5 and starch removal is poor.
Thus the oxygen bleach that is suitable for the invention
must be a selected organic peroxyacid which has its maximum
stain removal efficacy at a wash pH of about 8.5, which is
generally at, or near, the pKa of the peracid, and wherein a
1% aqueous solution has a pH of from 6 to about 9.
Note that while peracetic acid (PAA) has a pKa of 8.2, its
stain removal performance increases through the pH range 7 to
10. Thus, PAA would not be a preferred peracid bleach for use
in the inventive system. The same would be true of peracid
molecules with properties similar to monoperoxyphthalate and
monopersulphate, which are very hydrophilic in nature and
deliver poor tannin removal at low pH.
Typical organic peroxy acids which are useful include alkyl
peroxy acids and aryl peroxy acids such as:
(i) peroxybenzoic acid and ring-substituted peroxybenzoic
acids, e.g., peroxy-alpha-naphthoic acid.
(ii) aliphatic and substituted aliphatic moasoperoxy acids,
e.g., peroxylauric acid, peroxystearic acid,
epsilon-phthalimido peroxyhexanoic acid and o-
carboxybenzamido peroxyhexanoic acid, N-nonenyl-
amidoperadipic acid and N-nonenylamidopersuccinic acid.
Diperoxy acids may also be used as the organic peroxy acid
and include alkyl peroxy acids and aryldiperoxy acids, such
as:
(iii) 1,12-diperoxydodecanedioic acid
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(iv) 1,9-diperoxyazelaic acid ,
(v) diperoxybrassylic acid; diperoxysebacic acid and
diperoxy-isophthalic acid ,
{vi) 2-decyldiperoxybutane-1,4-dioic acid
(vii) N,N'-terephthaloyl-di(6-aminopercaproic acid).
Preferred organic peroxy acids include epsilon-
phthalimidoperoxyhexanoic acid (PAP), o-
carboxybenzamidoperoxyhexanoic acid, and mixtures thereof.
The organic peroxy acid is present in the composition in an
amount such that the level of organic peroxy acid in the wash
solution is 1 ppm to 100 ppm Av Ox, preferably 3 ppm to 50
ppm Av Ox, most preferably 5 ppm to 30 ppm Av Ox.
15-The organic peroxy acid may be incorporated directly into the
formulation or may be encapsulated by any number of
encapsulation techniques.
A preferred encapsulation method is described in US-A-
5,200,236. In the patented method, the bleaching agent is
encapsulated as a core in a paraffin wax material having a
melting point from about 40°C to about 50°C. The wax coating
has a thicl~ness of from 100 to 1500 microns.
Alpha (a) Amylase Enzymes
An effective amount of an amylase enzymeis used which, when
incubated at 55°C in a solution of 2mM sodium citrate, 1mM
epsilon phthalimidoperoxyhexanoic acid in 36 ppm water at pH
8.0, has a half-life of two minutes or greater based on an
activity vs. time plot obtained via monitoring color
development at 405nm of solution samples incubated with p-
nitrophenyl-cx-D-maltoheptaoside as substrate and gluco
amylase and a-glucosidose as coupled enzymes. A preferred
monitor is the Roche Cobas Fara Analyzer using Roche Reagent.
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Preferably, the half-life of the enzyme is 5 minutes or
greater, preferably 10 minutes or greater.
Such a-amylase enzymes with improved oxidation stability and
bleach resistance useful in the invention are described in
WO-94/02597 (Novo); WO-94/14951 (Novo) and EP-A-208,491
(Genencor International Inc.)_.
The a-amylase enzymes should be present in the detergent
-i 10 composition in an amount providing an enzyme activity level
in the wash solution of from about 50 mu/1 to about 5x10'
mu/1, preferably from about 100 mu/1 is about 2x10' mu/1,
more preferably from about 100 mu/1 to about 104 mu/1.
Amylolytic activity of the described a-amylases can be
determined by a conventional method such as the one described
in P. Bernfeld, Method of Enzymology, Vol. I (1995), pg. 149
The a-amylase is a mutated amylase wherein one or more
methionine amino acid residues is exchanged with an amino
acid residue except for cysteine or methionine.
A preferred type of the a-amylase is a Bacillus a-amylase.
More preferred types of the bleach resistant cx-amylase are
Bacjllus Iicheniformis cx-amylase, B. amyloliquefaciens a-
amylase and B. stearothermophilus cx-amylase, and furthermore
Aspergillus aiger ar-amylase. It has been found that this
entire group of mutant a-amylases exhibit a half-life of
greater than two minutes under the test conditions outlined
in the "Summary of the Invention".
A preferred embodiment of the mutant a-amylase is
characterized by the fact that one or more of the methionine
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amino acid residues is (are) exchanged with a Leu, Thr, Ala,
Gly, Ser, Ile, or Asp amino acid residue, preferably a Leu,
Thr, Ala, or Gly amino acid residue. In this embodiment a
very satisfactory activity level and stability in the
presence of the oxidizing agents is obtained.
A preferred embodiment of the mutant a-amylase is
characterized by the fact that the methionine amino acid
residue in position 197 in B. licheniformis a-amylase or the
methionine amino acid residue in homologous positions in
other cx-amylases is exchanged. The concept of homologous
positions or sequence homology of cx-amylase has been
explained e.g. in Nakajima, R. et al., 1986, Appl. Microbiol.
Biotechnol. ~, 355-360 and Liisa Holm et al., 1990, Protein
Engineering 3, 181-191. Sequence homology of Bacillus a-
amylases from B. licheniforms, B. stearothermophilus and B.
amyloliquefaciens are about 60%. This makes it possible to
align the sequences in order to compare residues at
homologous positions in the sequence. By such alignment of
a-amylase sequences the number in each cx-amylase sequence of
the homologous residues can be found. The homologous
positions will probably spatially be in the same positions in
a three dimensional structure (Greer, J., 1981, J. Mol. Biol.
153, 1027-1042) thus having analogous impact on specific
functions of the enzyme in question. In relation to position
197 a.n B. licheniformis a-amylase, the homologous positions
in B. stearothermophils a-amylase are positions 200 and 206,
and the homologous position in B. amyloliquefaciens a-amylase
is position 197. Experimentally it has been found that these
mutuants exhibit both an improved activity level and an
improved stability in the presence of oxidizing agents.
A preferred embodiment of the mutuant a-amylase according to
the invention is characterized by the fact that one or both
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of the methionine amino acid residues in positions 200 and
206 in B. stearothermophiius a-amylase or the methionine
amino acid residues in homologous positions in other a-
amylases are exchanged. In relation to positions 200 and 206
in B. stearotherrnophilus a-amylase the homologous position in
B. licheniforniis a-amylase is 197 and the homologous position
in B. amyloliquefaciens a-amylase is position 197.
Experimentally it has been found that these mutants exhibit
both an improved activity level and an improved stability in
the presence of the oxidizing agents.
As illustrated in Example 2, 3 and 4 below, the preferred a-
amylase was observed to exhibit a poor level of cleaning
performance in a wash liquor having a pH of 10 or greater
both in the presence and in the absence of an organic peroxy
acid bleach (e. g., PAP). Thus, the improved bleach stability
of the above described a-amylases gave little benefit in
cleaning performance when the amylases are formulated in
machine dishwashing compositions at pH levels greater than or
equal to 14.
In order to obtain improved levels of starch removal with a
detergent formulation containing a-amylases which are bleach
resistant, it was observed that the pH of the wash liquor
must be below 10, preferably 6 to 9.5, most preferably 7 to
9.5. (See Examples 5 and 6). As noted above, at a reduced
alkalinity of less than pH 10, traditional peroxygen
bleaching agents do not deliver a significant bleaching
benefit.
Therefore, according to the invention the above described a-
amylases must be formulated with an organic peroxy acid in a
detergent composition, provided that a 1% aqueous solution of
the detergent composition has a pH of from 6 to 9, to provide
overall effective performance on both starch and tannin.
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hetergent Builder Materials
The compositions of this invention can contain all manner of
detergent builders commonly taught for use in machine
dishwashing or other cleaning compositions. The builders can
5 include any of the conventional inorganic and organic
water-soluble builder salts, or mixtures thereof and may
comprise 1 to 75%, and preferably, from about 5 to about 70%
by weight of the cleaning composition,
10 Typical examples of phosphorus-containing inorganic builders,
when present, include the water-soluble salts, especially
alkali metal pyrophosphates, orthophosphates and
polyphosphates. Specific examples of inorganic phosphate
builders include sodium and potassium tripolyphosphates,
pyrophosphates and hexametaphosphates.
Suitable examples of non-phosphorus-containing inorganic
builders, when present, include water-soluble alkali metal
carbonates, bicarbonates, sesquicarbonates, borates,
silicates, metasilicates, and crystalline and amorphous
aluminosilicates. Specific examples include sodium carbonate
(with or without calcite seeds), potassium carbonate, sodium
and potassium bicarbonates, silicates and zeolites.
Particularly preferred inorganic builders can be selected
from the group consisting of sodium tripolyphosphate,
potassium tripolyphosphate, potassium pyrophosphate, sodium,
carbonate, potassium carbonate, sodium bicarbonate, sodium
silicate and mixtures thereof, When present in these
compositions, sodium tripolyphosphate concentrations will
range from about 2% to about 40%; preferably from 5% to 30%.
Potassium tripolyphosphate concentrations will range from
about 2% to about 50%, preferably from 5% to 40%. Sodium and
potassium carbonate and bicarbonate when present can range
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11
from about 5% to about 50%; preferably from 10% to 30% by
weight of the cleaning compositions. Sodium tripolyphosphate,
potassium tripolyphosphate and potassium pyrophosphate can be
used as builders in gel forntulations, where they may be
present from 3 to 50%, preferably from 10 to 40%.
Organic detergent builders can also be used in the present
invention. Examples of organic builders include alkali metal
citrates, succinates, malonates, fatty acid sulfonates, fatty
acid carboxylates, nitrilotriacetates, phytates,
phosphonates, alkanehydroxyphosphonates, oxydisuccinates,
alkyl and alkenyl disuccinates, oxydiacetates,
carboxymethyloxy succinates, ethylenediaaaine tetraacetates,
tartrate monosuccinates, tartrate disuccinates, tartrate
monoacetates, tartrate diacetates, oxidized starches,
oxidized heteropolymeric polysaccharides,
polyhydroxysulfonates, polycarboxylates such as
polyacrylates, polymaleates, polyacetates,
polyhydroxyacrylates, polyacrylate/polymaleate and
polyacrylate/ polymethacrylate copolymers, acrylate/
maleate/vinyl alcohol terpolymers, aminopolycarboxylates and
polyacetal carboxylates, and polyaspartates and mixtures
thereof. Such carboxylates are described in US-A-4,144,226,
US-A-4,146,495 and US-A-4,686,062.
Alkali metal citrates, nitrilotriacetates, oxydisuccinates,
polyphosphonates and acrylate/maleate copolymers and .
acrylate/maleate/vinyl alcohol terpolymers are especially
preferred organic builders. When present they are preferably
available from 1% to 35% of the total weight of the detergent
compositions.
The foregoing detergent builders are meant to illustrate but
not limit the types of builders that can be employed in the
present invention.
The composition may also include an enzyme selected from the group
consisting of a protease and a lipase in an effective amount to
remove soils.
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Anti-Scalant
Scale formation on dishes and machine parts is an important
problem that needs to be resolved or at least mitigated in
formulating a machine warewashing product, especially in the
case of low-phosphate (e.g. less than the equivalent of 20%
by weight, particularly 10°s by weight of sodium triphosphate)
and phosphate-free machine warewashing compositions,
particularly zero-P machine warewashing compositions.
In order to reduce this problem, co-builders, such as
polyacrylic acids or polyacrylates (PAA), acrylate/maleate
copolymers, and the various organic polyphosphonates, e.g. of
the Dequest~" range, may be incorporated in one or more system
components. For improved biodegradability, the block co-
polymers of formula (I) as defined in WO-94/17170 may also be
used. In any component, the amount of co-builder may be in
the range of from 0.5 to 10, preferably from 0.5 to 5, and
more preferably from 1 to 5°s by weight.
Surfactants
Useful surfactants include anionic, nonionic, cationic,
amphoteric, zwitterionic types and mixtures of these surface
active agents. Such surfactants are well known in the .
detergent art and are described at length in "Surface Active
Agents and Detergents", Vol. II, by Schwartz, Perry & Hirch,
Interscience Publishers, Inc. 19591
Preferred surfactants are one or a mixture of:
Anionic surfactants
Anionic synthetic detergents can be broadly described as
surface active compounds with one or more negatively charged
functional groups. An important class of anionic compounds
are the water-soluble salts, particularly the alkali metal
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- salts, of organic sulfur reaction products having in their
molecular structure an alkyl radical containing from about 6
to 24 carbon atoms and a radical selected from the group
consisting of sulfonic and sulfuric acid ester radicals.
Primary A11cy1 Su1 fa tes
Rl OSO~NI
where R' is a primary alkyl group of 8 to 18 carbon atoms and
M is a solubilizing ration. The alkyl group R' may have a
mixture of chain lengths. It is preferred that at least two
thirds of the R' alkyl groups have a chain length of 8 to 14
carbon atoms. This will be the case if R1 is coconut alkyl,
for example. The solubilizing ration may be a range of
rations which are in general monovalent and confer water
solubility. Alkali metal, notably sodium, is especially
envisaged. Other possibilities are ammonium and substituted
ammonium ions, such as trialkanol- or trialkyl-ammonium.
AIhy1 Ether Sulfates
2 0 RIO (CHaCH20) nSO~?
where R' is a primary alkyl group of 8 to 18 carbon atoms, n
has an average value in the range from Z to 6 and M is a
solubilizing ration. The alkyl group RI may have a mixture
of chain lengths. It is preferred that at least two thirds
of the RI alkyl groups have a chain length of 8 to 14 carbon
atoms. This will be the case if RI is coconut alkyl, for
example. Preferably n has an average value of 2 to 5.
Fatty Aci d Ester Sulfonates
3 0 RICH (S03M) CO~
where RZ.is an alkyl group of 6 to 16 atoms, R3 is an alkyl
group of 1 to 4 carbon atoms and M is a solubilizing ration.
The group RZ may have a mixture of chain lengths. Preferably
at least two thirds of these groups have 6 to 12 carbon
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atoms. This will be the case when the moiety RzCH(-)COZ(-) is -
derived from a coconut source, for instance. It is preferred
that .R3 is a straight chain alkyl, notably methyl or ethyl.
-AlJcy1 Benzene Sulfonates
R'~ArS03hl
where R4 is an alkyl group of 8 to 18 carbon atoms, Ar is a
benzene ring (C6FI4) and M is a solubilizing cation. The group
R'~ may be a mixture of chain lengths. Straight chains of 11
to 14 carbon atoms are preferred.
Organic phosphate based anionic surfactants include organic
phosphate esters such as complex mono- or diester phosphates
of hydroxyl- terminated alkoxide condensates, or salts
thereof. Included in the organic phosphate esters are
phosphate ester derivatives of polyoxyalkylated alkylaryl
phosphate esters, of ethoxylated linear alcohols and
ethoxylates of phenol. Also included are nonionic
alkoxylates having a sodium alkylenecarboxylate moiety linked
to a terminal hydroxyl group of the nonionic through an ether
bond. Counterions to the salts of all the foregoing may be
those of alkali metal, alkaline earth metal, ammonium,
alkanolammonium and alkylammonium types.
Particularly preferred anionic surfactants are the fatty
acid ester sulfonates with formula:
RzCH (SO3M) CO~
where the moiety RaCH(-) COa (-) is derived from a coconut
source and R3 is either methyl or ethyl.
'
Nonionic surfactants
Nonionic surfactants can be broadly defined as surface active
compounds with one or more uncharged hydrophilic
substituents. A major class of nonionic surfactants are
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those compounds produced by the condensation of alkylene
oxide groups with an organic hydrophobic material which may
- be aliphatic or alkyl aromatic in nature. The length of the
hydrophilic or polyoxyalkylene radical which is condensed
5 with any, particular hydrophobic group can be readily adjusted
to yield a water-soluble compound having the desired degree
of balance between hydrophilic and hydrophobic elements.
Illustrative, but not limiting examples, of various suitable
nonionic surfactant types are:
polyoxyethylene or polyoxypropylene condensates of aliphatic
carboxylic acids, whether linear- or branched-chain and
unsaturated or saturated, containing from about 8 to about 18
carbon atoms in the aliphatic chain and incorporating from
about 2 to about 50 ethylene oxide and/or propylene oxide
units. Suitable carboxylic acids include "coconut" fatty
acids (derived from coconut oil) which contain an average of
about 12 carbon atoms, "tallow" fatty acids (derived from
tallow-class fats) which contain an average of about 18
carbon atoms, palmitic acid, myristic acid, stearic acid and
lauric acid,
polyoxyethylene or polyoxypropylene condensates of aliphatic
aleohols, whether linear- or branched-chain and unsaturated
or saturated, containing from about 6 to about 24 carbon
atoms and incorporating from about 2 to about 50 ethylene
oxide and/or propylene oxide units. Suitable alcohols
include "coconut" fatty alcohol, "tallow" fatty alcohol,
lauryl alcohol, myristyl alcohol and oleyl alcohol.
Ethoxylated fatty alcohols may be used alone or in admixture
- with anionic surfactants, especially the preferred
surfactants above. The average chain lengths of the alkyl
group Rs in the general formula:
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RSO (CH2CHa0) nH
is from 6 to 20 carbon atoms. Notably the group RS may have
chain lengths in a range from 9 to 18 carbon atoms. _
The average value of n should be at least 2. The numbers of
ethylene oxide residues may be a statistical distribution
around the average value. However, as is known, the
distribution can be affected by the manufacturing process or
altered by fractionation after ethoxylation. Particularly
preferred ethoxylated fatty alcohols have a group RS which
has 9 to 18 carbon atoms while n is from 2 to 8.
Also included within this category are nonionic surfactants
having a formula:
Rd-(CH2CHU),~(CHsCH20)y(CIi~CHt~~yH
l~t~ Rs
wherein R6 is a linear alkyl hydrocarbon radical having an
average of 6 to 18 carbon atoms, R' and R$ are each linear
alkyl hydrocarbons of about 1 to about 4 carbon atoms, x is
an integer of from 1 to 6, y is an integer of from 4 to 20
~.nd z is an integer from 4 to 25.
A preferred nonionic surfactant of the above formula is
Poly-Tergent SLF-18' a registered trademark of the Olin
Corporation, New Haven, Conn. having a composition of the
above formula where R6 is a C6-Clo linear alkyl mixture, R' and
Rg are methyl, x averages 3, y averages 12 and z averages 16.
Another preferred nonionic surfactant is
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I7
R90 {CHsCHQ) j{CHsCH2U)k{CHy CH{dH}R1o)1
I
CHI
wherein R9 is a linear, aliphatic hydrocarbon radical having
from about 4 to about 18 carbon atoms including mixtures
thereof; and R1° is a linear, aliphatic hydrocarbon radical
having from about 2 to about 26 carbon atoms including
mixtures thereof; j is an integer having a value of from 1 to
about 3; k is an integer having a value from 5 to about 30;
and z is an integer having a value of from 1 to about 3.
Most preferred are compositons in which j is 1, k is from
about 10 to about 20 and 1 is 1. These surfactants are
described in WO-94/22800. Other preferred nonionic
surfactants are linear fatty alcohol alkoxylates with a
capped terminal group, as described in US-A-4,340,766.
Particularly preferred is Plurafac LF403 ex. BASF.
polyoxye~thylene or polyoxypropylene condensates of alkyl
phenols, whether linear- or branched-chain and unsaturated or
saturated,containing from about 6 to 12 carbon atoms and
incorporating from about 2 to about 25 moles of ethylene
oxide and/or propylene oxide.
polyoxyethylene derivatives of sorbitan mono-, d3-, and
tri-fatty acid esters wherein the fatty acid component has
between 12 and 24 carbon atoms. The preferred
polyoxyethylene derivatives are of sorbitan monolaurate,
sorbitan trilaurate, sorbitan monopalmitate, sorbitan
tripalmitate, sorbitan monostearate, sorbitan
~monoisos.tearate, sorbitan tripalmitate, sorbital tristearate,
t
sorbitan monooleate, and sorbitan trioleate. The
polyoxyethylene chains may contain between about 4 and 30
ethylene oxide units, preferably about 10 to 20. The
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sorbitan ester derivatives contain 1, 2 or 3 polyoxyethylene
chains dependent upon whether they are mono-, di- or tri-acid
esters.
polyoxyethylene-polyoxypropylene block copolymers having
formula:
HO ( CHaCHaO ) , ( CH ( CH3 ) CH~O ) b ( CH2CHa0 ) ~H
or
HO ( CH ( CH3 ) CHaO ) d ( CH2CHa0 ) ~ ( CH ( CH3 ) CHZO ) fFi
to
wherein a, b, c, d, a and f are integers from 1 to 350
reflecting the respective polyethylene oxide and poly-
propylene oxide blocks of said polymer. The polyoxyethylene
component of the block polymer constitutes at least about 10~
of the block polymer. The material preferably has a molecular
weight of between about 1,000 and 15,000, more preferably
from about 1,500 to about 6,000_ These materials are
well-known in the art. They are available under the trademark
"Pluronic" and "Pluronic R", a product of BASF Corporation.
Amine oxides having formula:
Ri2RisRi4N=O
wherein R12, Rts and Rt4 are saturated aliphatic radicals or
substituted saturated aliphatic radicals. Preferable amine
oxides are those wherein R'2 is an alkyl chain of about 10 to
about 20 carbon atoms and R13 and R14 are methyl or ethyl
groups or both R12 and RI3 are alkyl chains of about 6 to about
14 carbon atoms and R14 is a methyl or ethyl group_
.Amphoteric synthetic detergents can be broadly described as
derivatives of aliphatic and tertiary amines, in which the
aliphatic radical may be straight chain or branched and
wherein one of the aliphatic substituents contain from about
8 to about 18 carbons and one contains an anionic
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water-solubilizing group, i.e., carboxy, sulpho, sulphato,
phosphato or phosphono. Examples of compounds falling within
this definition are sodium 3-dodecylamino propionate and
sodium 2-dodecylamino propane sulfonate.
Zwitterionic synthetic detergents can be broadly described as
derivatives of aliphatic quaternary ammonium, phosphonium and
sulphonium compounds in which the aliphatic radical may be
straight chained or branched, and wherein one of the
aliphatic substituents contains from about 8 to about 18
carbon atoms and one contains an anionic water-solubilizing
group, e.g., carboxy, sulpho, sulphato, phosphato or
phosphono. These compounds are frequently referred to as
betaines. Besides alkyl betaines, alkyl amino and alkyl
amido betaines are encompassed within this invention.
AIIzy1 Glycosides
l2rSG (R16O) " ~ZI ) p
wherein Ris is a monovalent organic radical (e.g., a
monovalent saturated aliphatic, unsaturated aliphatic or
aromatic radical such as alkyl, hydroxyalkyl, alkenyl,
hydroxyalkenyl, aryl, alkylaryl, hydroxyalkylaryl, arylalkyl,
alkenylaryl, arylalkenyl, etc.) containing from about 6 to
about 30 (preferably from about 8 to 18 and more preferably
from about 9 to about 13) carbon atoms; R'6 is a divalent
hydrocarbon radical containing from 2 to about 4 carbon atoms
such as ethylene, propylene or butylene (most preferably the
unit (Rr60)n represents repeating units of ethylene oxide,
propylene oxide and/or random or block combinations thereof);
n is a number having an average value of from 0 to about 12;
ZI represents a moiety derived from a reducing saccharide
containing 5 or 6 carbon atoms (most preferably a glucose
unit); and p is a number having an average value of from 0.5
to about 10 preferably from about 0.5 to about 5 .
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Examples of commercially available materials from Her~lcel
Kommanditgesellschaft Alctien of Dusseldorf, Germany include
APG° 300, 325 and 350 with R15 being C9-C11, n is 0 and p is
1.3, 1.6 and 1.8-2.2 respectively; APG° 500 and 550 with Rls
5 is C12-C13, n is 0 and p is 1.3 and 1.8-2.2, respectively; and
APG° 600 with Rls being CIa-C14, n is 0 and p is 1.3.
While esters of glucose are contemplated especially, it is
envisaged that corresponding materials based on other
10 reducing sugars, such as galactose and mannose are also
suitable.
Particularly preferred anionic surfactants are the fatty
acid ester sulfonates with formula:
15 RICH (S03M) CO~
where the moiety RZCH(-) COa (-) is derived from a coconut
source and .R~ is either methyl or ethyl.
The amount of glycoside surfactant, anionic surfactant
20 andJor ethoxylated fatty alcohol surfactant will be from 0.5
to 40~ by weight of the composition. Desirably the total
amount of surfactant lies in the same range. The preferred
range of surfactant is from 0.5 to 30~ by weight, more
preferably from 0.5 to 15~ by weight.
ill r
An inert particulate filler material which is water-soluble
may also be present in cleaning compositions. This material
should not precipitate calcium or magnesium ions at the
filler use level. Suitable for this purpose are organic or
inorganic compounds. Organic fillers include sucrose esters
and urea. Representative inorganic fillers include sodium
sulfate, sodium chloride and potassium chloride. A preferred
filler is sodium sulfate. Its concentration may range from
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0% to 60%, preferably from about 5% to about 30% by weight of
the cleaning composition.
Thickeners and Stabilizers
Thickeners are often desirable for liquid cleaning
compositions. Thixotropic thickeners such as smectite clays
including montmorillonite (bentonite), hectorite, saponite,
and the like may be used to impart viscosity to liquid
cleaning compositions. Silica, silica gel, and alumino-
l0 silicate may also be used as thickeners. Salts of polyacrylic
acid (of molecular weight of fr~a about 300, 000 up to 6
million and higher), including polymers which are
cross-linked may also be used alone or in combination with
other thickeners. Use of clay thickeners for machine
dishwashing compositions is disclosed for example in US-A-
4,431,559; US-A-4,511,487; US-A-4,740,327; US-A-4,752,409.
Commercially available synthetic smectite clays include
Laponite supplied by Laporte Industries. Commercially
available bentonite clays include Korthix Hue' and VWH ex
Combustion Engineering, Inc.; Polargel T'" ex American Colloid'.
Co.; and Gelwhite'" clays (particularly Gelwhite GP and H) ex
English China Clay Co. Polargel T is preferred as imparting a
more intense white appearance to the composition than other
clays. The amount of clay thickener employed in the
compositions is from 0.1 to 10%, preferably 0.5 to 5%. Use of
salts of polymeric carboxylic acids is disclosed for example
in GH-A-2,164,350A, US-A-4,859,358 and US-A-4,836,948.
For liquid formulations with a 'gel" appearance and
rheology, particularly if a clear gel is desired, a chlorine-
resistant polymeric thickener is particularly useful. USA-
4,260,528 discloses natural gums and resins for use in clear
machine dishwashing detergents, which are not chlorine
stable. Acrylic acid polymers that are cross-linked
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manufactured by, for example, B.F. Goodrich and sold under
the trade name "Carbopol" have been found to be effective for
production of clear gels, and Carbopol 940, 617 and 627,
having a molecular weight of about 4,000,000 are particularly
preferred for maintaining high viscosity with excellent
chlorine stability over extended periods. Further suitable
chlorine-resistant polymeric thickeners are described in US-
A-4,867,896. The amount of thickener employed in the
compositions is from 0 to 5%, preferably 0.5-3%.
i
Stabilizers and/or co-structuraats such as long=chain calcium
and sodium soaps and C~x to Cls sulfates are detailed in US-A-
3,956,158 and US-A-4,271,030 and the use of other metal salts
of long-chain soaps is detailed in US-A-4,~~2,409o Qther
co-structurants include Laponite and metal oxides and their
salts as described in US-A-4,933,101. The amount of
stabilizer which may be used in the liquid cleaning
compositions is from 0.01 to 5% by weight of the composition,
preferably 0.01-2%. Such stabilizers are optional in gel
formulations. Co-structurants which are found especially
suitable for gels include trivalent metal ions at 0.01-4% of
the compositions, Laponite and/or water-soluble structuring
chelants at 0.01-5%. These co-structurants are more fully
described in US-A-5,141,664.
Anti-TarnishinoLAqents
Anti-tarnishing agents may be incorporated into the
compositions. Such agents include benzotriazole, certain 1,3
N-azoles described in US-A-5,480,576; isocyanuric acid
described in US-A-5,374,369; and purine compounds described
in US-A-5,468,410.
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Defoamer
The formulations of the cleaning composition comprising
surfactant may further include a defoamer. Suitable defoamers
include mono-and distearyl acid phosphate, silicone oil and
mineral oil. Even if the cleaning composition has only
defoaming surfactant, the defoamer assists to minimize foam
which food soils can generate. The compositions may include
0.02 to 2% by weight of defoamer, or preferably 0.05-1.0%.
Optional Ingredients
Minor amounts of various other components may be present in
the cleaning composition. These include bleach scavengers
including but not limited to sodium bisulfate, sodium
perborate, reducing sugars, and short chain alcohols;
solvents and hydrotropes such as ethanol, isopropanol and
xylene sulfonates; flow control agents (in granular forms);
enzyme stabilizing agents; soil suspending agents;
antiredeposition agents; anti-corrosion agents; ingredients
~~ enhance decor care such as certain aluminum salts
described in WO-96/36687 and US-A-5624892; colorants;
perfumes; and other functional additives.
The following examples will serve to distinguish this
invention from the prior art and illustrate its embodiments
more fully. Unless otherwise indicated, all parts,
percentages and proportions referred to are by weights.
EXAMPLE 1
The half-lives of amylases were determined by the method in
the specification. Thus, the amylase, at a level of
4x10'mu/1, was incubated at 55°C in a solution containing 2mM
sodium citrate, 1mM sodium citrate, 1mM epsilon
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phthalimidoperoxyhexanoic acid and 36 ppm hardness ions with
a calcium to magnesium ratio of 4:1 and maintained at pH 8Ø
Samples were withdrawn at suitable intervals and analyzed for
enzyme activity on a Roche Cobas Fara Analyzer using Roche
S Reagent. This contains p-nitrophenyl-a-D-maltoheptaoside as
the substrate which is hydrolyzed by the amylase in question
to give p-nitrophenylmaltotriose. This moiety is then
hydrolyzed by glycoamylase to p-nitrophenylmaltotriose, which
in turn is hydrolyzed by gluco amylase to p-nitrophenyl
glycoside aad further hydrolyzed by a-glucosideose to p-
nitrophenol. The absorbance of p-nitrophenol is measured at
405nm.
The results for Termanyl°", Duramyl'" and Purafect ~ OxAm 4000 G
(ex. Genencor) are given in Table 1.
Termamyl Duramyl Purafect~ OxAm
40006
<1 13 >20
Thus, Termamyl is outside the scope of the invention.
EXAMPhE 2
The amylolytic activity and starch removal performance of a
bleach resistant a-amylase (Duramyl~", supplied by Novo) was
compared to that of~a conventional amylase (i.e. Termamyl,
supplied by Novo) under model wash conditions in a beaker at
pH 10, 55°C.
Two detergent compositions were prepared, including an amount
of Duramyl'~ and Termanyl~' to provide an enzymatic activity
level of 220 Maltose units per liter in the wash solution.
Also included in the compositions were 0.2g/1 sodium
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nitrilotriacetate and carbonate/bicarbonate buffer
containing 1.7g/1 of NazC03.10Hs0 and 0.34g/1 of NaHC03. No
bleaching agent was added to either sample. The pH of an
aqueous solution of each of the compositons was adjusted to
5 pH 10 with NaOH or HzSO, as needed.
The amylolytic activity of the two types of enzyme was
determined as follows:
Model wash solutions containing carbonate/bicarbonate buffer,
10 builder (if present) and hardness ions (if present) are
' stirred in a constant temperature jacketed beaker. Enzyme
and bleach (if present) are added. Samples are withdrawn
from this solution at fixed times and added to solid starch
azure, a crystalline potato starch polymer linked with
15 Remazol"" Brilliant Blue. This.mixture is incubated for a set
time, centrifuged and the color development in the
supernatant measured. This experiment measures the change in
enzyme activity over time.
Absorbance values were recorded over a 60 minute time period.
20 The greater the absorbance value, the higher the activity of
the enzyme in the composition. The following results were
obtained at pH 10.
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TABLE 2
Absorbaace at 59611m (or Amylase Activity)
Elapsed time (min) Duramyl Termamyl
_ ._._ ._ i
0 0.44 1.23
10 0.53 1.17
20 0.27 1.24
30 0.29 1.23
40 0.25 1.23
50 0.23 1.30
60 0.22 1.26
At pH 10, with no bleach present, the conventional amylase
exhibited a significantly higher enzymatic activity than the
composition containing the a-amylase of the present
-invention.
The starch removal performance of the two samples was also
compared in an industrial dishwasher by washing three racks
of dishes, each rack being loaded with a range of dishware
that included ten starch-soiled plates. The components of
the cleaning composition were dosed into the machine just
once, prior to washing the first rack of dishes. Since there
was no further dosing of product, each successive wash
resulted in a 10~ dilution of the product concentration due
to the introduction of fresh rinse water at the end of each
main wash. There was a waiting period of 5 minutes between
the processing of the second and third racks of dishes. The
level of residual starch was assessed visually after
disclosure of the washed plate in iodine solution.
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Termamyl 300L and Duramyl 300L were each dosed to give 4 x
103 Mu/Q in the wash. The following results were obtained.
TABLE 3
Residual
Starch
(~ Area
)
Sample Rack 1 Rack 2 Rack 3
Termamyl 300L 13 13 12
Duramyl 300L 100 100 100
Consistent with the observed amylolytic activity profiles
above, at a wash pH of 10 and in the absence of bleach, the
composition containing the conventional amylase, Termamyl
300L, was observed to give significantly better starch
removal performance than the novel a-amylase when both were
incorporated in a detergent composition as described above.
FXaMT~T.F 3
The compositions of Example 2 were modified by incorporating
hydrogen peroxide (100 ppm Av Ox) or hypochlorite (60 ppm Av.
Cl) as bleaching agent. Three racks of soiled dishware were
washed as described in Example 2 and evaluated for residual
starch soil with the following results.
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TABLE 4
Residual '
Starch
( ~SArea
)
Bleach Eazyme Rack Raek 2 Rack
1 3
Hypochlorite Termamyl 300L 100 100 100
Duramyl 300L 100 100 100
Hydrogen Termamyl 300L 7 8 10
Peroxide
Duramyl 300L 100 100 100
Chlorine bleach has a devastating impact on the stability of
both amylase variants and so the cleaning results are poor in
both cases. There is a big improvement in enzyme stability
rahen the bleach is hydrogen peroxide. However, the starch
removal performance of both enzymes remained essentially
unchanged relative to the composition with no bleach
described in Example 2. Thus, a.n the presence of hydrogen
peroxide at pH 10, it is the conventional amylase, not the
bleach-resistant amylase that gives the better starch removal
performance.
EXAMPLE 4
Epsilon-phthalimido peroxyhexanoic acid (PAP) and peracetic
acid (PAA) were both used in lieu of the hydrogen peroxide as
peroxygen bleaching agent in the sample of Example 2
containing the Duramyl a-amylase. The pH of the wash
solution was adjusted to a value of 10. The starch removal
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performance of the composition containing Duramyl and these
peracids was also observed after three washing cycles as
described in Example 2. Residual starch levels were 70, 100
and 95~ respectively, when the bleaching agent was PAP, and
were 15, 100 and 100 respectively when the bleaching agent
was PAA.
Therefore, substituting the conventional oxygen bleaching
agent, hydrogen peroxide, with a more powerful peracid
bleaching agent (PAP or PAA) did not significantly improve
the starch removal performance of the Duramyl cx-amylase when
formulated in a detergent composition at pH 10, and therefore
at this wash pH there is still no benefit for this novel cx-
amylase over the conventional Termamyl amylase.
EXAMPLE 5
The amylolytic activity of both a bleach-resistant amylase
and Termamyl were monitored at a wash pH of 8.5, both in the
absence and presence of PAP. The technique used a.s the same
as that described in Example 2. The relative amylase
activities, based on absorbancies, are given in Table 6.
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Relative
Amylase
Activity
at pH
8.5
Elapsed Duramyl Duramyl Termamyl Termamyl
5 Time + PAP + PAP
(minutes)
0 1.25 2.5 0.75 0.75
5 1.0 2.4 1.0 0.5
10 1.0 2.25 1.0 0.8
15 0.85 1.7 1.0 0.2
10 20 0.90 1.25 1.0 0.2
30 1.0 1.0 1.0 0.2
Unexpectedly, the amylolytic activity of the formulation
containing the a-amylase according to the invention was
15 synergistically enhanced by addition of the peracid at pH
8.5. In contrast, the activity of Termamyl decreased on
addition of the PAP. This enhancement between the bleach-
resistant amylase and PAP did not occur at pH 10, as seen
from the absorbance data in Table 6.
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RELATIVE AMYLASE
ACTIVITY AT
pH 3Ø0
Elapsed time Duramyl Duramyl + PAP
(minutes)
0 0.14 0.06
5 0.11 0.05
0.12 0.10
0.08 0.18
10 20 0.06 0.04
30 0.06 0.05
Again, this is surprising since one would have expected
that as the pH moved down from pH 10 to pH 8.5, that is as
15 the pH moved to the range of greatest activity for PAP, the
effect on Duramyl would be negative, not positive. Also,
this positive synergistic benefit on the bleach-resistant
amylase activity occurs at the pH region where the
functionality of PAP (i.e. bleaching of tannin} is optimum.
EXAMPLE 6
The starch and tannin removal performance profiles were
determined for a bleach-resistant a-amylase in combination
with a wide range of peracid bleaching agents (i.e.
hydrophobic monoperoxy- and diperoxy-acids; hydrophilic
monoperoxy acid; inorganic peroxyacid).
The cleaning experiments were conducted in a domestic
dishwashing machine wherein the wash temperature was
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maintained at 55°C and the wash pH at 8.5 (with borate
buffer) or 10 (with carbonate/bicarbonate buffer). In one
type of experiment where only four times stained tea cups
were included, the wash time was 30 seconds. In a second
=teat, where a combination of soiled tea cups and starch
soiled plates were included, the wash time was 2 minutes.
The results of these tests are given in Table 8.
TABLE 8
30 second 2 minute
wash wash
PERACID Wash Residual Residual Residual
pii Tea+ Tea+ Starch
PAP 8.5 0 0 45
TPCAP* 8.5 0.7 0.8 39
DPDDA** 8.5 1.0 0_3 37
H48*** 8.5 2.4 1.5 26
H48 10 1.5 - -
KMPS**** 8.5 2.9 2.0 34
KMPS 10 2.0 - -
* N,N~-terephthaloyl-di (6-amino percaproic acid)
** 1,12-diperoxydodecanedioic acid
*** magnesium monoperoxyphthalate
**** potassium monopersulfate
+The stained tea cups are rated on a zero (no residual
stain) to five (heavy stain) scale. The difference between
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zero and non-zero tea scores is considered to be highly
significant because any residual tea stain rapidly builds up
during subsequent re-use and re-washing steps.
With regard to starch removal, the foregoing was designed to
be a highly stressed performance test in order to clearly
demonstrate differences. Differences in the starch removal
scores for KMPS, DPDDA, TPCAP, PAP and H48 systems at pH 8.5
are considered to be small and all systems are capable of
giving good levels of starch removal. However, there were
significant differences in tannin removal. H48 and KMPS gave
very poor levels of tannin removal at pH 8.5 and PAP was
significantly better than both DPDDA and TPCAP.
Thus, the system that gives overall the best tannin and
starch cleaning profile is the PAP/amylase system with the
other hydrophobic peracid/enzyme combinations some distance
behind.
2 0 E~CAMPLE 7
Surprisingly, it is found that the stability of Duramyl
towards bleach is greatly enhanced when builder is present in
the wash solution. A similar enhanced stability was not
observed with Termamyl. The amyloyltic activity was
monitored by the following method:
Starch azure, a crystalline potato starch polymer linked
with Remazol Brilliant Blue, is heated in distilled water at
80°C for 15 minutes and transferred to glass slides (1 inch x
1 inch) which are then dried at room temperature overnight.
The slides are weighed. Model wash solutions containing pH
8.5 borate buffer, builder (at 0.56g/1 if present) and
hardness ions (36ppm expressed as CaC03; 4:1 Ca:Mg ratio) are
stirred and maintained at 55°C in a constant temperature
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jacketed beaker. Three retrograded starch slides are added ,
to the beaker, followed by either Duramyl or Ternaa.myl and
then PAP (at 1mM). The absorbance of aliquots are measured ,
at 596 nm to give an assessment of in-wash enzyme activity.
In addition, at the end of the experiment, the slides are
dried and weighed to determine the level of soil removal.
The builders evaluated were sodium nitrilotriacetate,
sodium citrate and an acrylate/maleate/vinyl alcohol
terpolymer from Huls, described in U.S_ 4,686,062. The
activity of the enzymes was followed over a period of 30
minutes. The results are shown in Table 9.
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TABLE 9
Ingredients A B C D E F G H
NTA X J X X X J X X
5 Citrate X X ~ X X X J X
Huls X X X J X X X J
Polymer
Duramyl J J J J X X X X
Termamyl X X X X J J J J
10 PAP J J J J J J J J
Time Residual
(minutes) Amylolytic
Activity
0 100 10 100 l0 100 10 10 100
0 0 0 0
5 10 75 75 75 0 5 5 5
15 10 5 75 65 70 0 0 0 0
15 5 65 65 75 0 0 0 0
20 5 65 65 65 0 0 0 0
25 0 65 60 65 0 0 0 0
30 0 65 55 55 0 0 0 0
J means present in the wash solution.
* X means absent from the wash solution.
Good stability of the bleach-resistant amylase in the
presence of bleach is only obtained when builder is present
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in the wash solution (see B, C and D compared to A)_ A
similar enhancement of the stability of Termamyl, ~
traditional amylase, is not observed (see F, G, H compared
to E) .
EXAMPLE 8
Using the same procedure outlined in Example 7, the effect
of water hardness on the stability of a bleach-resistant
amylase in the presence of 2mM NTA and 20 ppm Av Ox PAP was
evaluated at 65°C. The activity of Duramyl was followed over
30 minutes. The results are shown in Table 10.
Table 10
Resish.al Amyl of y~ic Ac~iv3.tv
Time Water Hardness
(min.) (expressed
as CaC03;
4:1
Ca: Mg
ratio)
i
0 ppm 10 ppm 36 ppm 80 ppm
0 100 100 100 100
5 4 50 80 80
10 20 40 75 75
15 15 30 70 70
20 10 25 65 70
10 25 60 65
5 20 60 60
This demonstrates that hardness ions have a beneficial
effect on the amylolytic stability of the bleach-resistant K
enzyme in the presence of builder and PAP.
SUBSTITUTE SHEET (RULE 26)
