Note: Descriptions are shown in the official language in which they were submitted.
CA 022~809 1998-11-20
W097/4878S PCT~P97/030S9
IMPROVEMENTS RELATING TO BLEACHING COMPOSITIONS
Technlcal Field
The present invention relates to bleaching compositions,
and relates particularly to bleaching compositions which
can be used on fabrics either by direct application of the
composition to the fabric or as a wash additive.
~ackaround to the Inventlon
In household cleaning, fabric washing and in many other
areas there is a general need for agents which can ~bleach
unsightly materials, i.e. which can react with these
materials to decolourise them. One of the commonest of
such bleaching agents is sodium hypochlorite, which is
widely used in cleaning compositions to decolourise soils,
to assist in cleaning through its reaction with soils and
to kill micro-organisms.
Sodium hypochlorite is a powerful oxidising agent, which
can decolourise a very large number of coloured compounds
found in soils but which has significant limitations. Many
consumers prefer not to use chlorine-based bleach compounds
due the characteristic and pungent smell of chlorine.
There is a need for an alternative to chlorine-based
bleaching and bleaching and/or cleaning agents. One well
known class of alternatives are the peroxygen compounds.
Wash additives based on hydrogen peroxide and other
peroxides for laundry applications are well known. These
generally comprise a surfactant, a peroxygen bleaching
a~ent and a metal sequestering agent.
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CA 02255809 1998-11-20
WO 97/48785 rCT/EP97/03059
WO 9314183 (P&G: 1992) relates to a stable colourless
detergent composition of pH 4-11 which comprises:
a) 5-95%wt of anionic or nonionic surfactant ~which can
be a nonionic surfactant),
b) 0.005-10%wt of an oxygen bleach ~which can be hydrogen
peroxide),
c) 0.001-8% of a metal sequestering agent (which can be
sodium pyrophosphate or a DEQUEST(TM) type
sequestering agent).
Brief Descri~tlon of the Invention
We have determined that stable low pH peroxygen bleaching
compositions of pH less than 4 can be formulated using
disodium dihydrogen pyrophosphate in combination with a
second metal-ion complexing agent.
Accordingly, the present invention provides an aqueous
bleaching composition of pH 1-3 which comprises:
a) 0.1-15%wt surfactant
b) 3-15%wt hydrogen peroxide or a source thereof,
c) 0.5-10%wt disodium dihydrogen pyrophosphate,
d) 0.1-3%wt of at least one metal ion complexing agent
other than (c), and,
ei optionally, 0.01-1%wt perfume.
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WO 97/4878S P(~ 971030S9
The invention also provides a process for removing stains
from textile articles which comprises the step of treating
the articles with a composition as described herein.
Detalled Descrl~tlon of the Lnventlon
Compositions according to the present invention invariably
comprise at least 0.5%wt of disodium dihydrogen
pyrophosphate (o~herwise known as sodium acid
pyrophosphate) and have a pH in the range 1-3. The other
components present are subject to some variability as to
their precise nature and are discussed in further detail
below.
Surfactants
Preferred compositions according to the present invention
comprise 2-8%wt of surfactant on product. A broad range
of surfactants and surfactant combinations can be used in
the compositions of the invention. Surfactants can be
nonionic, anionic, cationic, amphoteric or zwitterionic
provided that they, and where appropriate their counter-
ions, do not react substantially with any peroxidecompounds present. Preferred surfactants are selected from
nonionic surfactants, anionic surfactants and mixtures
thereof.
Suitable nonionic detergent active compounds can be broadly
described as compounds produced by the condensation of
alkylene oxide groups, which are hydrophillic in nature,
with an organic hydrophobic compound which may be aliphatic
or alkyl aromatic in nature. The length of the
hydrophillic or polyoxyalkylene radical which is condensed
with any particular hydrophobic group can be readily
CA 022~809 1998-11-20
WO 9'7t48785 PCT/Er97/030S9
adjusted to yield a water-soluble compound having the
desired degree of balance between hydrophillic and
hydrophobic elements.
Particular examples include the condensation product of
aliphatic alcohols having from 8 to 22 carbon atoms in
either straight or branched chain configuration with
ethylene oxide, such as a coconut oil ethylene oxide
condensate having from 2 to 10 moles of ethylene oxide per
mole of coconut alcohol; condensates of alkylphenols whose
alkyl group contains from 6 to 12 carbon atoms with 2 to 10
moles of ethylene oxide per mole of alkylphenol.
The preferred alkoxylated alcohol nonionic surfactants are
ethoxylated alcohols having a chain length of C12-C15 and
an EO value of at least 2 but less than 10. Particularly
preferred nonionic surfactants include the condensation
products of Cl , alcohols with 3-9 moles of ethylene oxide.
An example of a suitable surfactant is ~Dobanol 25 7EO'
(TM, ex. Shell) a C, j. alcohol with seven moles of
ethoxylation.
When present, the amount of nonionic detergent active to be
employed in the composition of the invention will generally
be from 0.1 to 15~wt, preferably from 0.1 to 10%wt, and
most preferably frorn 4 to 10%wt.
We have also found it useful to employ a mixed nonionic
surfactant system which comprises two nonionics one of
which has a relatively high HLB and the other of which has
a relatively low HLB. In aqueous systems this combination
of nonionics forms a stable emulsion. An example of a
suitable system is one which comprises 2-5%wt each of two
C12-C15 alcohols ethoxylated with 2-4 and 6-8 moles of
ethylene oxide respectively. Two suitable nonionics are
CA 022~809 1998-11-20
WO 97/4878S PCT/EP97/03059
Dobanol 25 7EO [TM] ex. Shell and Dobanol 25 3EO [TM] ex.
Shell.
Alternative surfactants include amine oxides, amines and/or
ethoxylates thereof. Arnine oxides with a carbon chain
length of C12-C14 are particularly preferred.
Suitable anionic detergent active compounds are water-
soluble salts of organic sulphuric reaction products having
in the molecular structure an alkyl radical containing from
8 to 22 carbon atoms, and a radical chosen from sulphonic
acid or sulphur acid ester radicals and mixtures thereof.
Examples of suitable anionic detergents are sodium and
potassium alcohol sulphates, especially those obtained by
sulphating the higher alcohols produced by reducing the
glycerides of tallow or coconut oil; sodium and potassium
alkyl benzene sulphonates such as those in which the alkyl
group contains from 9 to 15 carbon atoms; sodium and
potassiurn secondary alkanesulphonates; sodium alkyl
glyceryl ether sulphates, especially those ethers of the
higher alcohols derived from tallow and coconut oil; sodium
coconut oil fatty acid monoglyceride sulphates; sodium and
potassium salts of sulphuric acid esters of the reaction
product of one mole of a higher fatty alcohol and from 1 to
6 moles of ethylene oxide; sodium and potassium salts of
alkyl phenol ethylene oxide ether sulphate with from 1 to 8
units of ethylene oxide molecule and in which the alkyl
radicals contain frorn 4 to 14 carbon atoms; the reaction
product of fatty acids esterified with isethionic acid and
neutralised with sodium hydroxide where, for example, the
fatty acids are derived from coconut oil and mixtures
thereof.
The preferred water-soluble synthetic anionic detergent
active compounds are the alkali metal (such as sodium and
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WO 97/48785 ~ 57/O~OS9
potassium) and alkaline earth metal (such as calcium and
magnesium) salts of higher alkyl benzene sulphonates and
mixtures with olefinsulphonates and higher alkyl sulphates,
and the higher fatty acid monoglyceride sulphates.
The most preferred anionic detergent active compounds are
higher alkyl aromatic sulphonates ~LAS) such as higher
alkyl benzene sulphonates containing from 6 to 20 carbon
atoms in the alkyl group in a straight or branched chain,
particular examples of which are sodium salts of higher
alkyl benzene sulphonates or of higher-alkyl toluene,
xylene or phenol sulphonates, alkyl naphthalene
sulphonates, ammonium diamyl naphthalene sulphonate, and
sodiu~ dinonyl naphthalene sulphonate. The most preferred
anionics also include the higher alcohol sulphates (also
known as alkyl sulphates) containing from 6 to 20 carbon
atoms in the alkyl group in a straight or branched chain,
particular examples of which are sodium salts of higher
primary alkyl sulphates (PAS).
The amount of synthetic anionic detergent active to be
employed in the detergent composition of this invention
will generally be from 0.1 to 15%, preferably from 1 to
5%wt, with levels of 1-2%wt being particularly preferred.
Preferably, the compositions contain an amount of both the
anionic and the nonionic detergent active. Preferably the
total surfactant content lies in the range 0.1-10%wt.
The weight ratio of anionic detergent to nonionic detergent
active may vary and will depend on their nature but is
preferably in the range of from 1:9 to 9:1, ideally from
1:4 to 4:1. We have decermined that a particularly
suitable surfactant system comprises 1-2% alkyl benzene
sulphonate and 0.5-2%wt ~12-15, 5-8 EO ethoxylated alcoho~
nonionic, a suitable alternative surfactant system
CA 022~809 1998-ll-20
W097/~78S PCT~P97tO30S9
comprises 1-2%wt of prlmary alcohol sulphate (also known as
primary alkyl sulphate) and 0.5-2%wt C12-15, 5-8 EO
ethoxylated alcohol nonionic.
Peroxlde
Suitable peroxy compounds for inclusion in compositions
according to the invention include, hydrogen peroxide,
perborates, persulphates, peroxysulphates, perphosphates,
periodates, percarbonates and mixtures thereof.
Particularly preferred materials are hydrogen peroxide,
sodium peroxide, peracetic acid, performic acid and mono-
persulphate salts. Hydrogen peroxide is most preferred.
Preferred compositions according to the present invention
comprise 5-10%wt hydrogen peroxide,
Metal ion c~mnlexln~ a~ents
Preferred compositions according to the present invention
comprise l-7%wt, more preferably 1-2~wt disodium dihydrogen
pyrophosphate. This material is otherwise known as sodium
acid pyrophosphate.
Preferred compositions according to the present invention
comprise 0.1-0.5%wt of at least one metal ion complexing
agent other than disodium dihydrogen pyrophosphate,
Preferably, cleaning and/or dislnfecting compositions
according to the invention will further comprise metal ion
sequestrants such as ethylene-diamine-tetra-acetates,
amino-polyphosphonates (such as those in the DEQUEST (TM)
range) and phosphates and a wide variety of other poly-
CA 022~809 l998-ll-20
W097/48785 PCT~P97/03059
functional organic acids and salts, can also optionally be
employed.
Preferred metal ion sequesterants are selected from
dipicolinic acid, ethylene diamine tetra acetic acid ~EDTA)
and its salts, hydroxy-ethylidene diphosphonic acid
(Dequest 2010, RTM), ethylene diamine tetra (methylene
phosphonic acid) (Dequest 2040, RTM), diethylene triamine
penta(methylene phosphonic acid) (Dequest 2060, RTM), amino
tri(methylene phosphonic acid) (Dequest 2000, RTM).
The phosphonic acid derivatives are particularly preferred.
Diethylene triamine penta(methylene phosphonic acid)
(Dequest 2060, RTM) is particularly preferred.
It is preferred that the level of phosphonic acid
derivative metal ion complexing agent should fall into the
range 0.~-3%wt, with levels of 0.1-0.5%wt being
particularly preferred.
Perfumes
Perfume is an optional component of the present invention
but is highly preferred. Preferred compositions according
to the present invention comprise 0.1-0.2%wt of perfume. A
wide range of perfumes can be employed provided that the
perfume is sufficiently stable in the composition.
Other Minors
Where compositions according to the present invention are
liquids, they can be water-thin or thickened. Thickened
compositions are advanta~eous in that they cling to sloping
surfaces and find particular utility in toilet cleaners.
CA 022~809 1998-11-20
WO 97/4878S PCT/E~97/030S9
Slight thickening of the composition is desirable for
applications in which the composition is sprayed, so as to
reduce the extent to which small droplets are produced
which might otherwise cause respiratory irritation to the
user. Suitable thickening agents include amine oxide and
soap and systems based on nonionic surfactants. Preferably
the compositions are no significantly thickened.
Compositions according to the invention can also contain,
in addition to the ingredients already mentioned, various
other optional ingredients such as, colourants, optical
brighteners, soil suspending agents, gel-control agents,
freeze-thaw stabilisers and opacifiers.
Preferably the pH of compositions according to the
invention is in the range 1.5-~.5. The pH of com~ositions
according to the invention can be regulated using acids,
preferably HCl and alkali~s, preferably NaOH.
In order that the invention can be further understood it
will be described hereafter with reference to the following
non-limiting examples.
Exam~les
The following compositions (as shown in table 2) were made
up using materials as identified in table 1.
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CA 02255809 lsss-ll-20
W097/48785 PCT~P97/03059
-- 10 -
Table 1
Material ¦ Sold as ¦ Supplier
::: : ~: ::
:. . . .... :
5 C12-15/7EO Dobanol 25 Shell
7EO[TM]
C12-15/3EO Dobanol 25 Shell
3EO[TM]
PAS Dacapon [TM] Unger
LAS (acid form) Made in house Lever Brothers
NaOH Caustic soda 47% ICI
Sequesterant Dequest 2060S[TM] Monsanto
Na~H- - Albright & Wilson
pyrophosphate
Perfume BAX 47867 IFF
The compositions were prepared by mixin~ the compounds as
indicating below in a stirring tank at room temperature..
No particular order of addition is required, although it is
preferred that the perfume and any dyestuff are added last.
CA 02255809 lsgs-ll-20
W097/48785 PCT~P97/030S9
Table 2
Comp ¦A ¦B ¦C ¦ D
C12-15/7EO 3.5% 1.0% 7.0% 1.0%
C12-15/3EO 3.5% - - -
PAS - 1.5~ - -
LAS (acid form) - - - 1.5%
NaOH - - - 0.176%
HCI 0.0215% 0.0215% 0.0215% 0.0215%
Sequesterant 0.15% 0.15% 0.15% 0.15%
H202 7.0~ 7.0% 7.0% 7.0%
Na-.H-. pyrophosphate 1.8% 1.8% 1.8% 1.8%
Perfume 0.15% 0.15% 0.15% 0.15%
Colour 0.0008% 0.0008~ 0.0008% 0.0008
Water to 100% to 100% to 100% to 100
pH ¦2.12 ¦2.00 ¦2.10 ¦1.93
All were found to be stable compositions which showed
acceptable bleaching behaviour when used as wash additives
and in direct application to soiled articles.
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