Note: Descriptions are shown in the official language in which they were submitted.
~9Z~36 C 546 (R)
The present invention relates to an enzymatic liquid
composition and more particularly to an enzymatic liquid
detergent composition with an improved storage stability.
Liquid detergent compositions are well known in the art
and, after the revival of interest in enzymes for inclusion
in detergent compositions, several proposals have been made
in the art for enzymatic liquid detergent compositions.
Despite khese proposals, such enzymatic liquid detergent
compositions have not been put on the market to any sig-
nificant extent, primarily because of severe instability
problems incurred with the incorporation of enzymes in
liquid detergent compositions. This problem is well recog-
nized in the art, and it has for instance been proposed
to reduce the instability of enzymes in liquid detergent
compositions by incorporating stabilizing systems in such
compositions.
Thus, for example, it has been proposed in Japanese
patent application 47/35,192, laid open to public inspection
, on 24th November, 1972, to prepare liquid, stabilized
~ 20 enzyme preparations, including enzymatic liquid detergent
rl, compositions, by incorporating therein a combination of
polyalcohols and borax. According to the specification of
said Japanese patent application, these polyalcohols,
examples of which are sorb1tol and glycerol, are used in
an amount of at least 5% by weight of the final composition,
preferably 10-30% by weight. The borax is used in at least
20%~ preferably 50-100% by weight of the polyalcohol. The
weight ratio of polyalcohol to borax in the composition
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~ C 546 (R)
~O~Z036 :
should therefore be equal to or greater than 1.
The compositions according to this prior proposal have
furthermore, ashasbeen experimentallydetermined by a repeat of
Example I, a p~-value in the range of 3.9 to 7.4.
It has now been found that the storage stability of
enzymatic liquid detergent compositions with a pH-value of
above 7.5, preferably between 8.5 and 11.0 (at 25C) can be
significantly improved by the inclusion bherein of a sta- ~-
bilizing system comprising one or more polyhydroxy compounds,
which will be defined more specifically hereafter, and boric
acid or a boron-equivalent thereof, the weight ratio of the
polyhydroxy compounds to the boric acid or equivalent there-
,~ of being sma~ler than l(calculated on the basis ofbora~. In
comparison with combinàtions according to the above Japanese
patent application, the systems of the present invention
;; demonstratea significantly improved enzyme stabillzing effect.
` The polyhydroxy compounds for use in the present in-
vention contain only C-, H- and O-atoms. They are free from
other (functional) substituting atoms such as N-, S- and
the like. The polyhydroxy compounds should contain at least
2 hydroxy groups, and may contain even up to 6 hydroxy
groups. Typical examples of polyhydroxy compounds particu-
larly suitable for use in the present invention are diols
such as 1,2-propanediol, ethyleneglycol, erythritan, poly-
ols such as glycerol, sorbitol, and mannitol.
In general, the polyhydroxy compound is present in
an amount of at least 4% by weight of the final composi-
tion, up to 25% by weight. Preferably the amount ranges
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C 546 (R)
~092~36
from 5-15% by weight of the final composition.
The boric acid or the boron-equivalent thereof, such as boric
oxide, borax and other alkali metal borates capable of reacting with a poly-
hydroxy compound, such as sodi~lm, ortho-, meta- and pyroborates, is used in
an amount such that the weight ratio of the polyhydroxy co~pound to the boron
compound is less than l(calculated onthe basis ofbora~.This
means thatthe boron compound isused in an amount of more than
I00% ofthe amount of the polyhydroxy compound. ~enerally the
amount varies from ~100-200% by weight, and preferably from
~100-160% by weight of the polyhydroxy compound.
The weight ratio of polyhydroxy compound to the boric
acid or equivalent is smaller than 1, generally from 0.5
up to just below 1.
The enzymatic liquid compositions in whichthe stabilizing
systems ofthe invention are incorporated can be aqueous liquid
systems, e.g.simple solutions,but they are-preferably aqueous liquid
detergent compositions comprising as essential ingredients enzymes, active
detergents and water, the pH being above 7.5, preferab~ between ~.5 and
11.0, or being adjusted thereto by proper means.
The enzymes to be incorporated can be proteolytic,
amylolytic and cellulolytic enzymes as well as mixtures
thereof. They may be of any suitable origin, such as vege-
table, animal, bacterialg fungal and yeast-origin. However,
their choice is governed by several factors such as pH-
activity and/or stability optima, thermostability, stabili-
ty versus active detergents, builders and so on. In this
respect bacterial or fungal enzymes are preferred, such
as bacterial amylases and proteases, and fungal cellulases.
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1~9Z~36
The present invention is of particular benefit for enzymatic
liquid detergents incorporating bacterial proteases of which
the pH-optima lie in the range between 8.o and 11.0, but it
is to be understood that enzymes with a somewhat lower or
higher pH-optimum can still be used in the compositions of
the invention, benefiting from it.
Suitable examples of proteases are the subtilisins
which are obtained from particular strains of B. subtilis
and B. licheniformis, such as the commercially available
subtilisins Maxatase ~ (ex Gist-Brocades N.V., Delft, Hol-
land) and Alcalase ~ (ex Novo Industri A/S, Copenhagen,
Denmark). :
As stated above, the present invention is of particular
benefit for enzymatic liquid detergents incorporating en-
zymes with pH-activity and/or stability optima of above
8.o, such as enzymes also commonly called high-alkaline
,~ enzymes.
Particularly suitable is a protease, obtained from a
strain of Bacillus, having maximum activity throughout the
pH-range of 8-12, developed and sold by Novo Industri A/S
under the registered trade name Esperase ~ . The prepara-
tion of this enzyme and analogous enzymes is described in
British patent specification 1,243,784 of Novo.
High-alkaline a~ylases and cellulases can also be
used, e.g. ~-amylases obtained from a special strain of
B. licheniformis, described in more detail in British
; patent specification 1,296,839 (Novo).
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~92~36 C 546 (R)
The amount of enzymes present in the liquid composition
may vary from D.001 to 10% by weight,and preferably from 0.01
to 5% by weight.
The liquid detergent compositions of the invention fur-
thermore comprise as essential ingredient an active detergent
material, which maybe an alkali metalor alkanol amine soap o~
a C1o-C24 fatty acid, including~olymerized fatty acids or an
anionic, nonionic, cationic, zwitterionic or amphoteric
synthetic detergent material,or mixtures of any of these.
Examples of anionic synthetic deter~ents are salts
(including sodium, potassium, ammonium, and substituted
ammonium salts such as mono-, di- and triethanolamine salts)
of Cg-C20 alkylbenzenesulphonates, C8-C22 primary or second-
ary alkanesulphonates, C8-C24 olefinsulphonates, sulphonated
polycarboxylic acids, prepared by sulphonation of the pyro-
lYzed product of alkaline earth metal citrates, e.g. as
described in British patent specification 1,082,179,
C8-C22 alkylsulphates, C8-C24 alkylpolyglycolethersulphates
(containing up to 10 moles of ethylene oxides); further
examples are described in "Surface Active Agents and De-
tergents" (Vol. I and II) by Schwartz, Perry and Berch.
Examples of nonionic synthetlc detergents are the con-
densation products of ethylene oxide, propylene oxide and/or
butyleneoxide with C8-C18 alkylphenols, C8 C18prlmary or sec-
ondary aliphatic alcohols,C8-C18 fatty acid amides; further ex-
amples of nonionics include tertiary amine oxides with one
C8-C18 alkyl chain and two C1 3 alkyl chains. The above
reference also describes further examples of nonionics.
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~9%036 C 546 (R)
The average number of moles of ethylene oxide and/or
propylene oxide present in the above nonionics varies from
1-30; mixtures of various nonionics, including mixtures of
nonionics with a lower and a higher degree of alkoxylation,
may also be used.
Examples of cationic detergents are the quaternary
ammonium compounds such as alkyldimethylammonium halogenides,
but such cationics are less preferred for inclusion in
enzymatic detergent compositions.
Examples of amphoteric or zwitterionic detergents are
; N-alkylamino acids, sulphobetaines, condensation products
of fatty acids with protein hydrolysates, but owing to
their relatively high costs they are usually used in com- !'
bination with an anionic or a nonionic detergent. Mixtures
of the various types of active detergents may also be used,
and preference is given to mixtures of an anionic and a
nonionic detergent active. Soaps (in the form of their ;
sodium, potassium, and substituted ammonium salts such as
triethanolamine salts) of Clo-C24 fatty acids, as well as
of polymerized fatty acids, may also be used,preferably in
conjunction with an anionic and/or a nonionic synthetic
detergent, and may exert a beneficial influence on the
foaming behaviour of the final composition.
The amount of the active detergent material varies
from 10 to 60%; when mixtures of e.g. anionics and non-
ionics are used the relative weight ratio varies from 1:1
to 1:10. When a soap is also incorporated, the amount there-
of is from 1-40% by weight.
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l~Z036 C 546 (R)
Although the liquids may contain up to 40% of a suitable
builder, such as sodium, potassium and ammonium or substituted
ammonium pyro- and tripolyphosphates, nitrilotriacetates,
etherpolycarboxylates, citrates, carbonates, orthophosphates,
polyelectrolytes such as polyvinylmethylether/maleic anhy-
dride copolymers and so on, the present invention is of
particular benefit for use in unbuilt liquid detergents.
` The amount of water present in the detergent compositions
of the invention varies from 5 to 70% by weight.
Other conventional materials may als~o be present in
the liquid detergent compositions of the invention, for
example soil-suspending agents, hydrotropes, corrosion in-
hibitors, dyes, perfumes, silicates, optical brighteners,
suds boosters, suds depressants, germicides, anti-tarnish~
ing agents, opacifiers, fabric-softening agents, oxygen-
liberating bleaches such as sodium perborate or percar-
bonate with or without bleach precursors, buffers and
the like.
The pH of the final composition is higher than 7.5
and should preferably lie within the range of 8.5 to
11.0, and is, if necessary, buffered to a value within
that range by addition of a suitable buffer system (e.g.
with dimethylglycine).
The invention will now be further illustrated by
way of Example. In the Examples the percentages are by
weight. In the Examples, the extension of the enzyme
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half-life time was determined in the following way:
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~ 9Z~36 C 5L~6 (R)
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A continuously withdrawn sample from a solution to be
tested was continuously diluted (1:200) and continuously
assayed on enzymatic activity (for proteolytic activity
casein was used as a substrate). The logarithms of the -
residual activity were plotted against the time, and the
~irst order rate constant K1 was computed.
The enzyme half-life time extension factor Ft is
defined as:
~t= K1 (without stabilizing system) = ty/2 (with ~tabilizing system)
.
K1~(with stabilizing system) ty/2 (without stabilizing system)
ty/2 = time, at which the enzymatic activity y is half the
initial enzymatic activity.
Example I
In this example, aqueous systems containing a bacterial
protease, Alcalase ~ ex Novo were tested. These aqueous
systems contained per litre:
0.2 Molar pentasodium tripolyphosphate
0.12 Molar dimethylglycine
` 1.7 g Alcalase ~ (activity 10.6 AU/g).
The pH of the solution was 10, and the temperature
57C. The rates of loss of activity of the enzyme were ~;
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measured in this system with and without the stabilizing
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systems as indicated hereunder, and the enzyme half-life
` time extension factor ~las determined. The following
'~ 25 results were obtained.
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~ -~ C 546 (R)
1~9Z0~6
No StabilizinF s~stem A~ounts Ratio -Ft
~ompound (P) Borax (B) - --- B pvalue
_ .
~ ethyleneglycol ~ 10 15.49.649 a6.7
2 " + 6 9.2 0.6528.3
3 " _ 10 _ _ 1.9
4 glycerol ~ 10 10.3 0.97014.7
" _ 10 _ _ 1.8
6 1,2-propanediol + 6 7-5 o.8 6.7
7 sorbitol + 10 10.5' 0.952 3-9
8 " + 10 5.2 1.9232.6
9 " _ 10 _ _ 1.7
mannitol + 10 10.5 0.9523.2
11 " + 10 5.2 1.9232.3
12 " _ 10 I _ 1.8
These results show the increased Ft-valu~es obtained with
the stabilizing systems of the invention. Tes~;sNos 8 and 11
are not according to the invention, (- ratio ~1), and show
that with these ratios significa~tly reduced Ft-values are
obtained, in comparison with - ratios ~1. Tests Nos 7-9 and
10-12 show that a reducing - ratio gives better Ft-values, in
contrast to the prior art which prescribes the - ratio to have
to be ~1. With 2%,4%, 8% and 9.45% borax only, (no polyhydroxy compound
added), the following Ft-values were obtained: 1.0, 1.3, 1.8 and 2.4.
Example II
In this series of experiments, a bacterial protease
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~ 546 (R)
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"Esperase" ~ ex Novo (activity 41.5 KNPU/g) was used. The
aqueous ~ystem was identical to that of Example I, but the
temperature was now 60C. With 4% erythritan and 7.4%
borax (B~- 54) a Ft of 2.5 was obtained.
Example III
In a manner analogous to that of Example I, systems
with a bacterial ~-amylase (Thermamyl~) were tested. The
aqueous system contained per litre:
0.12 M. pentasodium tripolyphosphate
1 o b .1 M. glycine
0.5 g Thermamyl (activity 450 KNU/g).
The pH was 9.95, and the temperature 59.3C.Wlth a -~
stabilizing system containing 6% ethyleneglycol ~ 9.2%
. . .: .
: borax (B ratio 0.65), an ~t-value of 2.2 was obtained.
` 15 Example I~
Example I was repeated with a stabiliæing system
containing 10% glycerol and varying amounts of borax. The
following results were obtained:
glycerol borax (%) P/B ratio ~t
a)10% throughout 14 0.71 11.6
b) 12 o.83 12.8
c) 11 0.91 14.1
d) 10.6 0.94 14.2
`' e) 10.35 0.97 14.7
' 25 f) 10 1.0 10.0
;; g) 8 1.25 6.8
. h) 6.25 1.6 4.7
" i) 5 2 3.4
j) 2.5 4 2.3
, k) 0 - 1.8
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