Note: Descriptions are shown in the official language in which they were submitted.
C 7319 (V)
CLEANING PROCESS
TECHNICAL FIELD
This invention relates to a cleaning process, and more in particular to a
process
for cleaning soiled articles such as fabrics, using an ultrasonic energy
source. In
particular, the invention relates to a process whereby soiled articles are
immersed in an enzymatic aqueous cleaning medium and radiated with
ultrasonic energy.
BACKGROUND AND PRIOR ART
Cleaning processes whereby ultrasonic energy is used have been known in the
art
for many years. In such a process, the articles to be cleaned are immersed in
an
aqueous cleaning medium and are radiated with ultrasonic energy. EP-A-
0,320,852discloses a process for cleaning articles whereby soiled articles are
immersed in an aqueous medium comprising lipase and radiated with ultrasonic
energy. In particular, numerous publications relate to ultrasonic fabric
washing
processes. For that purpose, the aqueous cleaning medium usually contains one
or more conventional ingredients of detergent products such as surfactants,
builders and the like. EP-A-258 8l6 (Henkel) discloses a ultrasonic fabric
washing process wherein the wash load is treated with a cleaning medium having
such a strong wetting capacity that the wash load is thoroughly wetted and de-
aerated.
It is also been suggested to incorporate enzymes in products for ultrasonic
fabric
washing. For example, EP-A-258 816 (Henkel) suggests the use of an enzymatic
aqueous medium in an ultrasonic fabric washing process. Suitable enzymes are
in
particular alkaline proteases. Lt is shown that the presence of an alkaline
protease in the wash liquor has a beneticial effect on the cleaning
performance
of the detergent product in an ultrasonic washing process.
AMENDED SHEET
IPEA/EP
la
It is mentioned but not exemplified that amylases, lipases, pectinases,
nucleases
and/or oxydoreductases can also be used.
AMENDED SHEET
IPEA/EP
7
Furthermore, JP-A-01026779 (Kao) discloses an ultrasonic fabric washing
process
whereby the cleaning solution contains a cellulase enzyme.
In his article in Chemistry and Industry 1990, pages 183-186, Malmos notes
that
it is known that generally the activity of lipases during a conventional
washing
process is low, and Lipolase (Trade mark of Novo/Nordisk) is no exception.
During the drying process, when the water content of the fabric is reduced,
any
remaining enzyme regains its activity and the fatty stains are hydrolysed.
During
the following wash cycle the hydrolysed material is removed. This also
explains
why the effect of lipases is low after the tirst washing cycle, but
significant in the
following cycles.
In view of these more recent findings, one skilled in the art would hardly
expect
any benefits from the presence of an enzyme having lipolytic activity in an
ultrasonic washing process, especially when considering the short contact time
which is in the order of minutes.
Contrary to what one would expect, we have now surprisingly found that the
incorporation of an enzyme having lipolytic activity into the aqueous cleaning
medium of an ultrasonic washing process leads to a significant improvement of
the wash performance.
DEFINITION OF THE INVENTION
According to the invention, there is provided a process for cleaning articles
whereby soiled articles are immersed in an enzymatic aqueous cleaning medium
and radiated with ultrasonic energy, wherein the cleaning medium comprises an
enzyme capable of hydrolying mono-, di- or triglyceride, characterised in that
the
enzyme has an activity of 0.1 to 500 LU/ml and the cleaning medium further
comprises surface active agents.
AMENDED SHEET
IPEA/EP
WO 94/07989 ~ ~ PCT/EP93/02559
-3-
DESCRIPTION OF THE INVENTION
In the process of the present invention, soiled articles
such as fabrics are immersed in an enzymatic aqueous
cleaning medium and radiated with ultrasonic energy.
The principles of ultrasonic washing are well known in the
art and can, for instance, be derived from the earlier
mentioned EP-A-258 816 (Henkel). For the purpose of this
application we define ultrasonic energy as usually
involving frequencies of about 10 kilo Hertz (kHz) to about
100 kHz, however, higher frequencies of up to 10 mega Hertz
(MHz) may also be used. In general, ultrasonic energy will
be applied to the enzymatic aqueous cleaning medium for
about 15 minutes or less, preferably between 0.25 to 10
minutes and more preferably between 0.5 to 5 minutes.
Optionally, the wash load may be agitated slowly,
preferably during "pulsing periods", i.e. periods in which
no ultrasonic energy is applied to the wash load.
The enzymatic aqueous cleaning medium used in the present
process comprises 0.05 to 50 g/1, preferably 0.1 to 10 g/1
(most preferably up to 5 g/1) of a conventional detergent
composition, which includes conventional detergent
ingredients such as surface active agents, builders, etc..
The surface active agents may be chosen from the
surfactants described "Surface Active Agents" Vol. 1, by
Schwartz & Perry, Interscience 1949, Vol. 2 by Schwartz,
Perry & Berch, Interscience 1958, in the current edition of
"McCutcheon's Emulsifiers and Detergents" published by
Manufacturing Confectioners Company or in "Tenside-
Taschenbuch", H. Stache, 2nd Edn., Carl Hauser Verlag,
1981. The surfactants preferably comprise one or more
nonionic and/or anionic surfactants. They may also comprise
amphoteric or zwitterionic detergent compounds, but this is
not normally desired owing to their relatively high cost.
WO 94/07989 PCT/EP93/02559
- 4 -
Suitable nonionic detergent compounds which may be used
include, in particular, the reaction products of com-pounds
having a hydrophobic group and a reactive hydrogen atom,
for example, aliphatic alcohols, acids, amides or alkyl
phenols with alkylene oxides, especially ethylene oxide
either alone or with propylene oxide. Specific nonionic
detergent compounds are C6-C22 alkyl phenol-ethylene oxide
condensates, generally 5 to 25 EO, i.e. 5 to 25 units of
ethylene oxide per molecule, and the condensation products
of aliphatic C8-Clg primary or secondary linear or branched
alcohols with ethylene oxide, generally 5 to 10 EO. Other
examples of suitable nonionic surfactants are alkyl poly-
glycosides and polyhydroxy fatty acid amide surfactants
such as disclosed in WO-A-92/06154 (Procter & Gamble).
Suitable anionic detergent compounds which may be used are
usually water-soluble alkali metal salts of organic
sulphates and sulphonates having alkyl radicals containing
from about 8 to about 22 carbon atoms, the term alkyl being
used to include the alkyl portion of higher acyl radicals.
Examples of suitable synthetic anionic detergent compounds
are sodium and potassium alkyl sulphates, especially those
obtained by sulphating higher C8-C18 alcohols, produced for
example from tallow or coconut oil, sodium and potassium
alkyl C9-C2o benzene sulphonates, particularly sodium
linear secondary alkyl C1o-C15 benzene sulphonates; and
sodium alkyl glyceryl ether sulphates, especially those
ethers of the higher alcohols derived from tallow or
coconut oil and synthetic alcohols derived from petroleum.
The preferred anionic detergent compounds are sodium C12-
C18 alkyl sulphates owing to their favourable compatibility
with lipolytic enzymes.
Surface active agents may preferably be present in amounts
of from 0.1% by weight of the composition, more preferably
0.5% by weight and preferably up to 70% by weight, more
preferably up to 60o by weight of the composition. For use
WO 94/07989 0 ~ ~ PCT/EP93/02559
-5-
in fabric washing the level of surface active agents is
preferably from 5% by weight, more preferably from 10% by
weight and preferably up to 60 % by weight, more preferably
up to 40 % by weight, most preferably up to 35% by weight.
For use in the mechanical washing of dishes the level of
surface active agents is preferably from 0.5% by weight to
amounts to about 60% by weight depending upon their type
and properties. Preferably low-to non-foaming nonionic
surfactant are used in properly built or highly built
compositions in amounts to 7% by weight. Higher levels of
highly detersive surfactants, i.e. up to 70% by weight,
preferably 60% by weight, may be used in lower builder
containing active/enzyme-based compositions.
Preferably the concentration of surface active agents in
the wash liquor is from 0.001 to 20 g/1, preferably from
0.05 to 10 g/1, most preferably up to 5 g/1.
The enzymatic detergent composition used in the present
invention may further contain from 5 to 60%, preferably
from 20 to 50% by weight of a detergency builder. This
detergency builder may be any material capable of reducing
the level of free calcium ions in the wash liquor and will
preferably provide the composition with other beneficial
properties such as an alkaline pH, the suspension of soil
removed from the fabric and the suspension of the fabric-
softening clay material.
Examples of suitable detergency builders include
precipitating builders such as the alkali metal carbonates,
bicarbonates, orthophosphates, sequestering builders such
as the alkali metal tripolyphosphates or
nitrilotriacetates, or ion exchange builders such as the
amorphous alkali metal aluminosilicates or the zeolites.
The characteristic feature of the process of the present
invention is that an enzyme having lipolytic activity is
WO 94/07989 PCT/EP93/02559
~1 ~-~-0 ~3 _
used in the ultrasonic cleaning process. In principle, any
enzyme having sufficient lipolytic activity may be used in
the process. Preferably a lipase derived from micro-
organisms are used, more preferably a bacterial or fungal
lipase. Most preferably the enzyme having lipolytic
activity is selected from Thermomyces lipases or variants
thereof, cutinases or variants thereof, Pseudomonas lipases
or variants thereof, Fusarium lipases or variants thereof
and/or Chromobacter lipases or variants thereof.
There are various publications on lipolytic enzymes or
lipases. For example, EP-A-214 761 (Novo/Nordisk) gives
detailed description of lipases derived from organisms of
the species Pseudomonas cepacia, and certain uses therefor.
EP-A-258 068 (Novo/Nordisk) gives detailed description of
lipases derived from organisms of the genus Thermomyces
(previous name Humicola) and certain uses therefor.
Examples of known lipase-containing detergent compositions
are provided by EP-A-205 208 and EP-A-206 390 (Unilever)
which relate to a class of lipases defined on the basis of
their immunological relationships, and describe their use
in detergent compositions and textile washing. The
preferred lipases are those derived from P. fluorescens, P.
ctladioli and Chromobacter species.
EP-A-331 376 (Amano) describes lipases and their production
by rDNA technique, and their use, including an amino acid
sequence of lipase from Pseudomonas cepacia. Further lipase
enzymes produced by rDNA technique are described in for
example WO-A-89/09263 (Gist-Brocades) and EP-A-218 272
(Gist-Brocades).
In spite of the large number of publications on lipase
enzymes and their modifications, only the lipase from
Humicola lanuginosa has so far found wide-spread commercial
2~.~4~63
7
application as additive for fabric washing products. It is available from
Novo/Nordisk under the trade name Lipolase~.
Other lipases that can be used in the present invention are lipases derived
from
Pseudomonas pseudoalcaligenes and variants thereof, e.g. Liponax~, and lipases
derived from Pseudomonaas putida and variants thereof, e.g. Lumafast~.
Furthermore, it should be noted that there are a number of publications
describing various hydrolase enzymes which are also capable of hydrolysing
mono-, di-, or triglycerides. For example, WO-A-90/09446 (Plant Genetics
Systems) discloses a cutinase enzyme from Fusarium solani pisi which is
capable
of hydrolysing triolein. Because there appears to be some contusion with
regard
to the nomenclature of these enzymes, we define an enzyme having lipolytic
activity for the purposes of this patent application as any enzyme capable of
hydrolysing mono-, di-, or triglycerides. The cutinase gene from Fusarium
solani
i~si has been cloned and sequenced (Ettinger et al., (1987) Biochemistry 26,
7883-7892). WO-A-90/09446 (Plant Genetics Systems) describes the cloning and
production of this gene in E. coli.
The present invention also provides a number of combinations of the enzyme
having lipolytic activity and further, conventional constituents used in
detergent
systems, to provide useful advantage in the ultrasonic removal of fatty
material
and material adsorbed to the fatty material in soil on textile.
The other components of such detergent compositions can be of any of many
known kinds, for example as described in GB-A-1 372 034 (Unilever), US-A-3
950 277, US-A-4 Ol 1 169 and EP-A-179 533 (Procter & Gamble), EP-A-205 208
and EP-A-206 390 (Unilever), JP-A-63-078000 (Lion), and Research Disclosure
29056 of June 1988. In several useful embodiments the detergent compositions
can be formulated as described in EP-A-407 225.
AIdIENDED SHEET
IPEA/EP
2144aG3
8
The enzyme havlllg lipolytic activity can usefully be added to the detergent
composition in the form of a granular composition, a solution or a slurry of
lipolytic enzyme with carrier material (e.g. as in EP-A-258 068 and
Savinase°
and Lipolase° products of Novo/Nordisk).
The amount of enzyme hamng lipolytic activity can be chosen within wide
limits.
Preferably, the enzymatic aqueous cleaning medium contains 0.1 to 500 LU/ml.
It is especially preferred to use about 0.5 to 50 LU/ml. In this specification
lipase units are defined as they are in EP-A-258 068 (Novo/Nordisk), which is
based on hydrolysis of tributyrin in a pH-stat. 1 LU (Lipase Unit) is the
amount
of enzyme which liberates 1 ~I1101 titratable butyric acid per minute at
30°C,pH
7.0 with gum arabic as an emulsitier. Similar considerations apply mutatis
mutandis in the case of other enzymes, which may also be present.
Advantage may be gained in such detergent compositions, where protease is
present together with the enzyme having lipolytic activity, by selecting such
protease from those having pI lower than 10. Preferably, the protease is
present
in the enzymatic aqueous cleaning medium in an amount of from 0.1 to 500
GU/1. A GU is a Glycerine Unit, defined as the proteolytic enzyme activity
which, under standard conditions, during a 15 minute-incubation at 40 deg C,
with N-acetyl casein as substrate, produces an amount of NH2 group equivalent
to 1 micromole of glycine. EP-A-271 154 (Unilever) describes a number of such
proteases. Proteases for use together with lipolytic enzyme may include
subtilisin
of for example BPN' type or of some of the other types of subtilisin disclosed
in
the literature, some of which have already been proposed for detergents use,
e.g.
mutant proteases as described in for
AMENDED SHEET
IPEA/EP
~l~~Qfi~
_8a_
example EP-A-130 756 (Genentech), US-A-4 760 025 (Genencor), EP-A-214 435
(Henkel), WO-A-87/04661 (Amgen), WO-A-87/05050 (Genex), Thomas et al.
(1986) in Nature 5, 316, and 375-376 and in J.Mol.Biol. (1987) 193, 803-813,
Russel et al. ( 1987) in Nature 328, 496-500, and others.
WO-A-92/08779 (Procter & Gamble) discloses liquid detergent compositions
comprising a lipase and a modified bacterial serine protease, which is said to
be
more compatible with the lipase. The proteases are modiEed in that the
AMENDED SHEET
IPEA/EP
WO 94/07989 ~ ~ PCT/EP93/02559
_g_
methionine adjacent to the active-site serine has been
replaced by another amino acid.
The formulation of detergent compositions according to the
invention can be further illustrated by reference to the
Examples D1 to D14 of EP-A-407 225 (Unilever).
It should be pointed out here that the cleaning process of
the present invention is not only suitable for cleaning
fabrics, but the principle of the invention can also be
applied in the cleaning of other soiled objects such as
dishes and/or other table ware, or medical equipment.
The invention is now further and non-limitatively
illustrated in the following Examples. The experimental
setup is shown in Figure 1.
WO 94/07989 PCT/EP93/02559
_ 10 _
EXAMPLE 1
The following wash experiments were performed in a standard
Tergotometer containing 1 1 of tap water (9° German
Hardness). Eight EMPA 101 (ex Eidgenossische Material-
s priifungsanstalt St. Gallen, Switzerland) test cloths of 7 x
7 cm were washed for 10 minutes at a temperature of 30°C,
at an agitator speed of 100 rpm. The ultrasonic energy was
supplied by a Branson ultrasonic probe having a tip of 1/8"
with a mean power of 38 Watt. The operating frequency was
23 kHz. The experimental setup is shown in Figure 1. The
wash liquor contained 3 g/1 of a detergent product having
the following composition (in % by weight):
Dodecyl Benzene Sulphonate 11.2
Ethoxylated alcohol nonionic surfactant 7 EO 4.6
Soap (pristerine 4950) 1.0
Sodium tripolyphosphate 39.5
Sodium carbonate 3.9
Sodium silicate ~.3
Sodium carboxymethyl cellulose 0.6
Fluorescer 0.2
Sodium sulphate 31.7
Water rest
After the washing, the reflectance at 460 nm was used to
monitor the cleaning action. The results are shown in the
Table. It is clear that the lipase effect, which is the
difference between the reflectance at 460 nm after the
ultrasonic wash in the presence and in the absence of
lipase, increases with the lipase concentration.
WO 94/07989 ~ ~ PCT/EP93/02559
_ 11 _
EXAMPLE 2
Example 1 was repeated using the following detergent
product at 2.6 g/1:
Dodecyl Benzene Sulphonate 8.0
Ethoxylated alcohol nonionic surfactant 12 EO 1.8
Ethoxylated alcohol nonionic surfactant 6 EO 0.7
Ethoxylated alcohol nonionic surfactant 7 EO 2.2
Alf5 0.8
Zeolite 42.0
Acrylic/Maleic copolymer (CP5 ex BASF) 4.0
Sodium silicate 1.0
Calcium bequest 0.3
Sodium sulphate 18.0
Water and minors 12.6
The cleaning results are shown in the Table. It can be seen
that the lipase effect for this phosphate-free formulation
is significantly better than for the phosphate containing
formulation used in example 1.
EXAMPLE 3
Example 1 was repeated using the following detergent
product at 2 g/1:
Dodecyl Benzene Sulphonic acid 16.0
C12-C15 Ethoxylated alcohol nonionic surfactant 7 EO 7.0
Monoethanol amine 2.0
Citric acid 6.5
Sodium xylene sulphonate 6.0
Sodium hydroxide 4.1
protease 0.5
Minors and water to 100%
The cleaning results are shown in the Table. The lipase
effect in this anionic-rich detergent composition is rather
small.
WO 94/07989 PCT/EP93/02559
- 12 -
EXAMPLE 4
Example 1 was repeated using the following detergent
product at 3 g/1:
C12-C15 Ethoxylated alcohol nonionic surfactant 10.5-13 EO
9.0
Sodium sulphate 36.8
Sodium carbonate 38.5
Sodium silicate 7.0
l0 Diatomeous Earth 1.9
Sodium carboxymethyl cellulose 0.1
Fluorescer 0.1
Water and minors to 100%
The cleaning results are shown in the Table. It can be seen
that the lipase effect in this nonionic-rich detergent
composition is large.
WO 94/07989 ~ ~ PCT/EP93/02559
- 13 -
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EXAMPLE 5
Polyester EMPA test clothes of Example 1, soiled with 3 wt%
tri-glycerol-oleate, were washed with 2 liter water
comprising 4.6 g Borax. The pH of the wash liquor was
adjusted to 9.2 using a HC1 solution, and further the
liquor had 5 FH. A US bath was used at 33 kHZ, 80 Watt, at
30°C for 30 minutes. The level of H3 labelled glycerol in
the wash liquor was determined and the detergency % (i.e.
the percentage of the total soil that is removed after the
wash) was determined for wash liquor without enzyme having
lipolytic activity, for wash liquor comprising additionally
LU/ml lipolase and for wash liquor comprising
additionally 10 LU/ml cutinase (derived from the cutinase
gene from Fusarium solani~isi that is described in
Ettinger et al., (1987) Biochemistry 26, 7883-7892). The
following results were obtained.
Ilipolytic enzyme I detergency % I
I- I ~
Ilipolase~ I 59 I
( I (
Icutinase I 85 I
The results show increased detergency for wash liquor
comprising an enzyme having lipolytic activity. It is
believed that the wash results will be even better when
surface active agents are present, e.g. as regards anti-
redeposition.
