Laundry Detergent Composition

Field of the invention
The present invention relates to the use of hydroxamic acid and
its corresponding salts in laundry detergent compositions with
low levels of zeolite and phosphate builder, leading to
improved detergency and stain removal.

Background of the invention
Improvement of stain removal is one of the constant goals of
the detergent industry, as this may lead to savings on the use
of chemicals in detergent compositions, or may lead to washing
at lower temperatures, and/or for shorter times, and therewith
saving energy. Therefore, there is still an interest to improve
the detergency effect, especially the primary detergency effect
of laundry detergent compositions on textile stains, for
example particulate stains, such as stains comprising soils or
clay, or plant based stains, such as grass. Especially
particulate stains are difficult to remove during the
laundering process.
Hydroxamic acids are a class of chemical compounds in which a
hydroxylamine is inserted into a carboxylic acid. The general
structure of a hydroxamic acid is the following:
o
Formula 1
in which R is an organic residue, for example alkyl or
alkylene groups. The hydroxamic acid may be present as its
corresponding alkali metal salt, or hydroxamate .
The hydroxamates may conveniently be formed from the
corresponding hydroxamic acid by substitution of the acid
hydrogen atom by a cation:
(Formula 2 )
L+ is a monovalent cation such as for example the alkali metals
(e.g. potassium, sodium), or ammonium or a substituted
ammonium.
Hydroxamic acids and hydroxamates are known to be useful as
metal chelators. They have also been used in detergent
compositions in order to improve bleaching performance, as well
as use as a builder substance.
EP 388 389 A2 discloses bleach free under built liquid
detergent compositions containing hydroxamic acids and their
derivatives which assist in the removal of bleachable wine
stains from fabrics during laundering. Hydroxamic acids as in
formula 1 are disclosed, wherein R represents an optionally
substituted straight- or branched chain C5-C2 1 alkyl or C5-C2 1
alkenyl group or an optionally-substituted phenyl group, and R
represents hydrogen, or an optionally substituted C 1-C6 alkyl
group, or an optionally-substituted phenyl group. One of the
examples shows an improved bleaching performance when a
hydroxamate is used in a detergent composition in hard water
(20° German hardness, which is about 143 milligram calcium per
litre) . The examples use C12 linear, C12 branched, C13 branched
and C i8 hydroxamates in detergent formulations comprising
mixtures of anionic surfactant and nonionic surfactant. In
examples I , II and IV there is an excess of nonionic surfactant
of at least 1.25 to 1 and in example III there is 100 anionic
surfactant. The liquids also contain at least 6 wt% ethanol,
which assists in solubilising the long chain hydroxamates.
EP 384 912 A2 discloses the use of hydroxamic acids and their
derivatives as stabilizers for peroxygen bleach compounds in
built, mainly granular, detergent compositions. Fully
formulated detergent powder examples with 2 0 wt% zeolite used
C12 , Ci3 and C12 branched hydroxamates. C s was also used.
US 4,874,539 discloses polymeric carboxy hydroxamic acids
useful as detergent additives, especially as metal ion
chelating agents, and also leading to improved tea stain
removal from a test cloth, as compared to a detergent powder
without a metal ion chelating agent.
US 4,863,636 discloses liquid detergent compositions comprising
one or more detersive surfactants and one or more of Nhydroxyimide
or carboxy hydroxamic acid detergent additives.
These compounds serve as active metal ion chelants, leading to
improved stain removal.
WO 97/48786 discloses a multicomponent system for use with
detergent substances, containing an oxidation catalyst, a
suitable oxidant, at least one mediator that has been selected
from the group of, among others, hydroxamic acids and
hydroxamic acid derivatives, a co-mediator, and optionally a
low quantity of at least one free amine of each inserted
mediator. This system leads to improved bleach function of the
detergent, and less consumption of a mediator.
GB 1317445 discloses detergent compositions comprising an
alkali-metal salt of a hydroxamic acid. The function of this
salt is to prevent the corrosion of copper and copper alloys
that is utilised in the construction of the washing machines.
Copending patent application PCT/EP2 009/0 67193 describes
laundry detergent formulations comprising 0.5 to 20% by weight
hydroxamic acid or its corresponding hydroxamate having a
structure as specified therein. It is also shown in this
document that the primary detergent effect, especially on red
clay particulate soil, can be improved when applying these
laundry detergent formulations for treating soiled fabric.
It has now surprisingly been found that this beneficial effect
can also be obtained when using laundry detergent formulations
similar to those of PCT/EP2009/067193 but containing less than
0.5% by weight hydroxamic acid or its corresponding
hydroxamate .
Laundry detergents need to be able to remove everyday dirt and
stains that are commonly found in a wash load. Two particular
satains that are problematic, especially when children's wear
or sport's wear is being washed, are clay soil stains and grass
stains. One type of clay that is particularly resistant to
removal by surfactants alone is red clay, such as red pottery
clay or Red Georgia clay. This is a particulate soil stain.
Definition of the invention
Accordingly, the present invention provides a laundry detergent
composition comprising
a ) 0.005 to less than 0.5 wt% hydroxamic acid or its
corresponding hydroxamate of the structure:
R
wherein R is
a straight or branched C 4- C 2 0 alkyl, or
a straight or branched substituted C 4- C 2 0 alkyl, or
a straight or branched C 4- C 2 0 alkenyl, or
a straight or branched substituted C 4- C 2 0 alkenyl, or
an alkyl ether group C¾ ( CH2 ) n (EO) m wherein n is from 2 to 2 0
and m is from 1 to 12, or
a substituted alkyl ether group CH3 (CH2)n (EO) m wherein n is
from 2 to 2 0 and m is from 1 to 12, and
the types of substitution include one or more of -N¾, -OH,
C OH
II I
- C - N
-S-, -0-, -COOH, and
and R2 is selected from hydrogen and a moiety that forms part
of a cyclic structure with a branched R group,
b ) 3 to 80 wt% of detersive surfactant system comprising
(i) anionic surfactant; and
(ii) nonionic surfactant,
wherein the ratio of (i) to (ii) lies in the range 1:1.1 to
19:1, and
wherein the weight ratio a ) to b ) lies in the range 1 : 6 to
1:16000, and
c ) optionally, other ingredients to 100 wt% provided that
zeolite and phosphate builders are present at less than 5 wt%
and ethanol is present at a level of less than 5 wt%.
It should be understood that references to a number of carbon
atoms include mixed chain length materials provided that some
of the hydroxamate material falls within the ranges specified
and the ratios and amounts are determined by excluding any
material falling outside of the specified range.
Soap is not included in the calculation of anionic surfactant
amounts and ratios.
It is undesirable to have ethanol present at all as it is an
explosion hazard during manufacture, and subsequently. If a
high level of surfactant is present, it is desirable to seek
alternative hydrotrope systems. We prefer a hydrotrope system
comprising propylene glycol and glycerol at levels of at least
6 wt%, more preferably at least 10 wt%.
The preferred hydroxamates are those where R2 is Hydrogen and R
is C to Ci4 alkyl, preferably normal alkyl, most preferably
saturated .
The detergent composition is preferably used in aqueous wash
liquor, but may comprise one or more solvents suitable for use
for domestic laundry purposes. Preferably, the improved stain
removal occurs during the main wash of the laundry process,
i.e. preferably the laundry detergent composition in which the
hydroxamates are used is a main wash product. The wash liquor
is preferably free of formate salts. Furthermore, it is
preferably free from bleach, especially peroxygen bleach.
The composition may comprise from 1 to 15 wt% soap. The
preferred soaps are made from saturated fatty acids.
Especially preferred compositions comprise at least 0.5 wt% of
soil release polymer. This improves the multiwash performance
of the detergent system for the removal of the clay. Inclusion
of at least 0.5 wt% anti redeposition polymer is also
beneficial due to the very high efficiency of primary
detergency soil removal meaning that there is an increased
level of soil in the wash liquor, which must then be prevented
from redeposition onto the same or a different piece of fabric
The preferred weight ratio of hydroxamate to detersive
surfactant system for optimum particulate red clay soil removal
lies in the range 1:10 to 1:400. An even more preferred range
of weight ratios being 1:20 to 1:100.
The preferred ratio of anionic to nonionic surfactant for
particulate red clay soil removal is at least 1:1, more
preferably at least 3:2. Preferably, it is at most 9:1. So
most preferred range is 1:1 to 9:1, or 3:2 to 9:1.
The compositions are particularly suitable for use on
particulate stains such as soils and clays, especially red
clay, and also surprisingly grass.
The invention also extends to the use of 0.005 to less than 0.5
wt% hydroxamic acid or its corresponding hydroxamate of the
structure :
o
wherein R is a C normal alkyl group, and R is a hydrogen
atom, in a laundry detergent composition, for improving the
particulate soils stain removal from a textile substrate,
wherein the composition further comprises a detersive
surfactant system comprising anionic surfactant and nonionic
surfactant at a concentration from 3 to 80 wt%; and optionally
other ingredients to 100 wt%.
The hydroxamate may be incorporated within the laundry
detergent compositions in any suitable fashion within the
knowledge of a person of ordinary skill in the art.
Detailed Description of the Invention
Whenever either the term hydroxamic acid' or hydroxamate' is
used in this specification, this encompasses both hydroxamic
acid and the corresponding hydroxamate (salt of hydroxamic
acid), unless indicated otherwise.
All percentages mentioned herein are by weight calculated on
the total composition, unless specified otherwise. The
abbreviation wt%' is to be understood as % by weight of the
total composition.
The stained fabric is treated with the laundry detergent
composition comprising hydroxamate according to the invention
and the primary detergency is the measured stain removal by the
laundry composition on the stain. This is a separate process to
so-called soil release using a polymer, which is treatment of
fabric with a polymer (through a wash or other such treatment) ,
with subsequent staining of the fabric, the soil release
polymer having the effect of the easier removal of the stain.
The following definitions pertain to chemical structures,
molecular segments and substituents :
Molecular weights of monomers and polymers are expressed as
weight average molecular weights, except where otherwise
specified .
The textile/fabric substrates used can be any typical
textile/fabric substrate, such as cotton (woven, knitted &
denim) , polyester (woven, knitted & micro fibre) , nylon, silk,
polycotton (polyester/cotton blends) , polyester elastane,
cotton elastane, viscose rayon, acrylic or wool. Particularly
suitable textile/fabric substrates are cotton, polycotton and
polyester substrates.
Particulate stains are stains comprising for example dirt,
soil, clay, mud or soot. They are predominately solid in nature
and come into contact with fabrics in the course of their
regular use.
Hydroxamic acid and derivatives
The general structure of a hydroxamic acid in the context of
the present invention has been indicated in formula 3 , and R ,
is as defined above. When R , is an alkyl ether group C¾ (C¾ ) n
(EO) m wherein n is from 2 to 2 0 and m is from 1 to 12 then the
alkyl moiety terminates this side group. Preferably, R is
chosen from the group consisting of C , C5, , C , Cs, Cg, Cio,
Cii, or Ci2 or C i normal alkyl group, most preferably R is at
least a C -i normal alkyl group. When the C material is used
this is called octyl hydroxamic acid. The potassium salt is
particularly useful.
eta noh yd r mic acid s t
However, other hydroxamic acids, whilst less preferred, are
suitable for use in the present invention. Such suitable
compounds include, but are not limited to, the following
compounds :
Lysine Hy roxam ate
Meth io nine Hydroxamate Norv aline H d r xa mate
Such hydroxamic acids are commercially available.
Without wishing to be bound by theory, we believe that the
hydroxamate acts by binding to metal ions that are present in
the soil on the fabric. This binding action, which is, in
effect, the known sequestrant property of the hydroxamate is
not, in itself, of any use to remove the soil from the fabric.
The key is the "tail" of the hydroxamate i.e. the group R
minus any branching that folds back onto the amate Nitrogen via
group R2 . The tail is selected to have an affinity for the
surfactant system. This means that the soil removal ability of
an already optimised surfactant system is further enhanced by
the use of the hydroxamate as it, in effect, labels the
difficult to remove particulate material (clay) as "soil" for
removal by the surfactant system acting on the hydroxamate
molecules now fixed to the particulates via their binding to
the metal ions embedded in the clay type particulates. The
detersive surfactants will adhere to the hydroxamate, leading
overall to more surfactants interacting with the fabric,
leading to better soil release. Therewith the hydroxamic acids
act as a linker molecule facilitating the removal and
suspension of the particulate soil from the fabric into a wash
liquor and thus boosting the primary detergency.
This enhancing of the primary detergency of surfactant systems
is especially relevant when using concentrated liquid detergent
compositions, as the pH during the laundering process is
relatively low (pH 7.5-8) as compared to traditional laundering
processes with particulate detergent compositions (pH 9-10.5).
The lower pH during the laundering process with liquid
detergent compositions may lead to reduced soil release, as the
surface charges of the soils are less negative as compared to
the higher pH during the conventional well built and buffered
laundering processes, achieved with conventional zeolite or
phosphate built powder products. This surface charge of the
soil may lead to increased repellence of the surfactants by the
soil, possibly leading to reduced release of the soil. Hence,
in a preferred embodiment, the hydroxamates are used in liquid
detergent compositions, and more preferred the detersive
surfactant concentration in said liquid detergent compositions
is from 2 0 to 80 wt%.
The hydroxamates have a higher affinity for transition metals,
like iron, than for alkaline earth metals like calcium and
magnesium, therefore the hydroxamic acid primarily acts to
improve the removal of soil on fabric, especially particulate
soils, and not additionally as a builder for calcium and
magnesium. This selectively is especially beneficial if the
laundering composition is underbuilt; especially when it
comprises less than 5 wt% zeolite or phosphate builder.
Surfactants
The laundry detergent composition in which the hydroxamate is
used comprises a detersive surfactant system at a concentration
from 3 to 80 wt%. By a detersive surfactant system, we mean
that the surfactants therein provide a detersive, i.e. cleaning
effect to textile fabrics treated as part of a laundering
process. Other surfactants, which are not detersive
surfactants, can be used as part of the composition.
Preferably, the detersive surfactant is present at a level of
from 5 to 60 wt%, more preferably from 10 to 50 wt%. Even more
preferably, the detersive surfactant system comprises at least
20, or 30 or even 40 wt% of the composition.
In general, any surfactant may be used as detersive
surfactants, including anionic, nonionic, cationic, and
amphoteric or zwitterionic surfactants, or combinations of
these, provided that there is anionic and nonionic surfactant
present in the range of ratios specified above.
Cationic surfactant may optionally be present as part of the
detersive surfactant.
Anionic surfactant may be present at a level of from 0.1 to 50
wt%, preferably from 1 to 40 wt%, more preferably from 1.5 to
25 wt%. Nonionic surfactant may be incorporated at a level of
from 0.1 to 50 wt%, preferably from 1 to 40 wt , more
preferably from 1.5 to 25 wt%. The ratio of anionic surfactant
to nonionic surfactant is from 19:1 to 1:1.1, more preferably
from 9:1 to 1:1.
In general, the nonionic and anionic surfactants of the
surfactant system may be chosen from the surfactants described
in 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.
Nonionic surfactant
For the purposes of this disclosure, nonionic surfactant'
shall be defined as amphiphilic molecules with a molecular
weight of less than about 10,000, unless otherwise noted, which
are substantially free of any functional groups that exhibit a
net charge at the normal wash pH of 6-11.
Any type of nonionic surfactant may be used, although preferred
materials are further discussed below. Highly preferred are
fatty acid alkoxylates, especially ethoxylates, having an alkyl
chain of from C8-C35, preferably C8-C30, more preferably C 0-C24,
especially C 0-C carbon atoms, for example, the Neodol range
from Shell (The Hague, The Netherlands) ; ethylene
oxide/propylene oxide block polymers which may have molecular
weight from 1,000 to 30,000, for example, Pluronic (trademark)
from BASF (Ludwigshaf en, Germany) ; and alkylphenol ethoxylates,
for example Triton X-100, available from Dow Chemical (Midland,
Mich. , USA) .
Other nonionic surfactants should also be considered within the
scope of this invention. These include condensates of
alkanolamines with fatty acids, such as cocamide DEA, polyolfatty
acid esters, such as the Span series available from
Uniqema (Gouda, The Netherlands) , ethoxylated polyol-fatty acid
esters, such as the Tween series available from Uniqema (Gouda,
The Netherlands) , alkylpolyglucosides , such as the APG line
available from Cognis (Dusseldorf, Germany) and nalkylpyrrolidones
, such as the Surfadone series of products
marketed by ISP (Wayne, N.J., USA) . Furthermore, nonionic
surfactants not specifically mentioned above, but within the
definition, may also be used.
The more preferred nonionic surfactants are the fatty acid
ethoxylates with an average degree of ethoxylation of 7 ,
alkoxylates with one propylene oxide and multiple ethylene
oxide units, seed oil based surfactant, such as Ecosurf SA7 or
SA9 available from Dow Chemical, APGs, and branched alcohol
Guerbet nonionics.
Anionic surfactant
Anionic surfactants' are defined herein as amphiphilic
molecules comprising one or more functional groups that exhibit
a net anionic charge when in aqueous solution at the normal
wash pH of between 6 and 11.
Preferred anionic surfactants are the alkali metal salts of
organic sulphur 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
sulphonic and sulphuric acid ester radicals.
Although any anionic surfactant hereinafter described can be
used, such as alkyl ether sulphates, soaps, fatty acid ester
sulphonates, alkyl benzene sulphonates, sulphosuccinate esters,
primary alkyl sulphates, olefin sulphonates, paraffin
sulphonates and organic phosphate; preferred anionic
surfactants are the alkali and alkaline earth metal salts of
fatty acid carboxylates , fatty alcohol sulphates, preferably
primary alkyl sulfates, more preferably they are ethoxylated,
for example alkyl ether sulphates; alkylbenzene sulphonates,
alkyl ester fatty acid sulphonates, especially methyl ester
fatty acid sulphonates and mixtures thereof.
Cationic amphoteric surfactants and/or zwitterionic
surfactants
Also cationic, amphoteric surfactants and/or zwitterionic
surfactants may be present in the laundry detergent
compositions in which the hydroxamate is used as cosurfactant
according to the invention.
Preferred cationic surfactants are quaternary ammonium salts of
the general formula R R2R3R + X , for example where R is a Ci2 _
C i4 alkyl group, R 2 and R 3 are methyl groups, R is a
2-hydroxyethyl group, and X is a chloride ion. This material
is available commercially as Praepagen (Trade Mark) HY from
Clariant GmbH, in the form of a 40% by weight aqueous solution.
In a preferred embodiment the laundry detergent composition in
which the hydroxamate is used according to the invention
further comprises an amphoteric or zwitterionic surfactant.
Amphoteric surfactants are molecules that contain both acidic
and basic groups and will exist as zwitterions at the normal
wash pH of between 6 and 11. Preferably an amphoteric or
zwitterionic surfactant is present at a level of from 0.1 to
20% by weight, more preferably from 0.25 to 15% by weight, even
more preferably from 0.5 to 10% by weight.
Suitable zwitterionic surfactants are exemplified as those
which can be broadly described as derivatives of aliphatic
quaternary ammonium, sulfonium and phosphonium compounds with
one long chain group having about 8 to about 18 carbon atoms
and at least one water solubilizing radical selected from the
group consisting of sulfate, sulfonate, carboxylate, phosphate
or phosphonate. A general formula for these compounds is:
R i (R 2)xY+R3Z
wherein R contains an alkyl, alkenyl or hydroxyalkyl group
with 8 to 18 carbon atoms, from 0 to 10 ethylene-oxy groups or
from 0 to 2 glyceryl units; Y is a nitrogen, sulphur or
phosphorous atom; R2 is an alkyl or hydroxyalkyl group with 1
to 3 carbon atoms; x is 1 when Y is a sulphur atom and 2 when Y
is a nitrogen or phosphorous atom; R 3 is an alkyl or
hydroxyalkyl group with 1 to 5 carbon atoms and Z is radical
selected from the group consisting of sulfate, sulfonate,
carboxylate, phosphate or phosphonate.
Preferred amphoteric surfactants are amine oxides, for example
coco dimethyl amine oxide.
Preferred zwitterionic surfactants are betaines, and especially
amidobetaines . Preferred betaines are C to Cis alkyl
amidoalkyl betaines, for example coco amido betaine. These may
be included as co-surfactants, preferably present in an amount
of from 0 to 10 wt % , more preferably 1 to 5 wt % , based on the
weight of the total composition. Other betaines that may be
employed are sulf atobetaines , such as 3-
(dodecyldimethylammonium) -1-propane sulfate; and 2-
(cocodimethylammonium) -1-ethane sulfate. Sulf obetaines , such
as: 3- (dodecyldimethyl-ammonium) -2-hydroxy-l-propane sulfonate;
3- (tetradecyl-dimethylammonium) -1-propane sulfonate; 3- (C 2-C
a1 y1-ami dopropyl dimethyl ammonium) -2-hydroxy-l-propane
sulfonate; and 3- (cocodimethylammonium) -1-propane sulfonate.
Carboxybetaines , such as (dodecyldimethylammonium) acetate
(also known as lauryl betaine) ; (tetradecyldimethylammonium)
acetate (also known as myristyl betaine) ;
(cocodimethylammonium) acetate (also known as coconut betaine) ;
(oleyldimethylammonium) acetate (also known as oleyl betaine) ;
(dodecyloxymethyldimethylammonium) acetate; and (cocoamidopropyldimethylammonium)
acetate (also known as cocoamido-propyl
betaine or CAPB) .
The sulf oniumbetaines , such as: (dodecyldimethylsulf onium)
acetate; and 3- (cocodimethyl-sulf onium) -1-propane sulfonate.
The phosphoniumbetaines , such as 4- (trimethylphosphonium) -1-
hexadecane sulfonate; 3- (dodecyldimethylphosphonium) -1-
propanesulf onate ; and 2- (dodecyldimethylphosphonium) -1-ethane
sulfate .
The laundry detergent compositions preferably comprise
carboxybetaines or sulphobetaines as amphoteric or zwitterionic
surfactants, or mixtures thereof. Especially preferred is
lauryl betaine. The betaines and hydroxamates may provide even
further enhanced particulate soil removal when used together in
the compositions according to the invention.
Detergency builders
The laundry detergent compositions in which the hydroxamate is
used preferably comprise low levels of detergency builder,
based on the weight of the total composition. The amounts of
the inorganic builders zeolite and phosphate are less than 5
wt%. These builders are considered to be harmful to the
environment when used in large quantities. Furthermore they
need to be used at high levels to have a significant building
effect and this is inconsistent with the modern concentrated
highly weight efficient laundry detergent formulations.
Preferably the builder is selected from the group of alkali and
alkaline earth metal carbonates (e.g. sodium carbonate),
silicates (e.g. layered silicate), and organic builders such as
citrates (e.g. sodium citrate), succinates, sulphamates and
malonates, and any combination of these. The organic builders
are preferred. They may be used at levels of 1 wt% or more, up
to, say, 50 wt%.
Organic builders that may be present include polycarboxylate
polymers such as polyacrylates and acrylic/maleic copolymers;
polyaspartates ; monomeric polycarboxylates such as citrates,
gluconates, oxydisuccinates , glycerol mono-di- and
trisuccinates , carboxymethyloxysuccinates , carboxymethyloxymalonates
, dipicolinates , hydroxyethyliminodiacetates ,
alkyl- and alkenylmalonates and succinates; and sulphonated
fatty acid salts.
Organic builders may be used in minor amounts Especially
preferred organic builders are citrates, suitably used in
amounts of from 1 to 30 wt%, preferably from 1.5 to 10 wt%; and
acrylic polymers, more especially acrylic/maleic copolymers,
suitably used in amounts of from 0.5 to 15 wt%, preferably from
1 to 10 wt%.
Builders, both inorganic and organic, are preferably present in
alkali metal salt, especially sodium salt, form.
Other optional Ingredients
In addition to the essential components detailed in the claims,
the formulation may include one or more optional ingredients to
enhance performance and properties. While it is not necessary
for these elements to be present in order to practice this
invention, the use of such materials is often very helpful in
rendering the formulation acceptable for consumer use.
Examples of optional components include, but are not limited
to: hydrotropes, fluorescent whitening agents, photobleaches ,
fibre lubricants, reducing agents, enzymes, enzyme stabilising
agents (such as borates and polyols) , powder finishing agents,
defoamers, bleaches, bleach catalysts, soil release agents,
especially soil release polymers for cotton or polyester or
both, antiredeposition agents, especially antiredeposition
polymers, dye transfer inhibitors, buffers, colorants,
fragrances, pro-fragrances, rheology modifiers, anti-ashing
polymers, preservatives, insect repellents, soil repellents,
water-resistance agents, suspending agents, aesthetic agents,
structuring agents, sanitisers, solvents, including aqueous and
non-aqueous solvents, fabric finishing agents, dye fixatives,
wrinkle-reducing agents, fabric conditioning agents and
deodorizers .
These optional ingredients may include, but are not limited to,
any one or more of the following: soap, peroxyacid and persalt
bleaches, bleach activators, sequestrants , cellulose ethers and
esters, other antiredeposition agents, sodium sulphate, sodium
silicate, sodium chloride, calcium chloride, sodium
bicarbonate, other inorganic salts, fluorescers, photobleaches ,
polyvinyl pyrrolidone, other dye transfer inhibiting polymers,
foam controllers, foam boosters, acrylic and acrylic/maleic
polymers, proteases, lipases, cellulases, amylases, other
detergent enzymes, citric acid, soil release polymers, fabric
conditioning compounds, coloured speckles, and perfume.
The laundry detergent composition may suitably contain a bleach
system based on peroxy bleach compounds, for example, inorganic
persalts or organic peroxyacids, capable of yielding hydrogen
peroxide in aqueous solution. Suitable peroxy bleach compounds
include organic peroxides such as urea peroxide, and inorganic
persalts such as the alkali metal perborates, percarbonates ,
perphosphates , persilicates and persulphates . Preferred
inorganic persalts are sodium perborate monohydrate and
tetrahydrate, and sodium percarbonate. Especially preferred is
sodium percarbonate having a protective coating against
destabilisation by moisture. Sodium percarbonate having a
protective coating comprising sodium metaborate and sodium
silicate is disclosed in GB 2 123 044B (Kao) .
The peroxy bleach compound is suitably present in an amount of
from 5 to 35% by weight, preferably from 10 to 25% by weight.
The peroxy bleach compound may be used in conjunction with a
bleach activator (bleach precursor) to improve bleaching action
at low wash temperatures. The bleach precursor is suitably
present in an amount of from 1 to 8% by weight, preferably from
2 to 5% by weight.
Preferred bleach precursors are peroxycarboxylic acid
precursors, more especially peracetic acid precursors and
peroxybenzoic acid precursors; and peroxycarbonic acid
precursors. An especially preferred bleach precursor suitable
for use in the present invention is N , , ', '-tetracetyl
ethylenediamine (TAED) . Also of interest are peroxybenzoic acid
precursors, in particular, N , ,N-trimethylammonium toluoyloxy
benzene sulphonate.
A bleach stabiliser (heavy metal sequestrant) may also be
present. Suitable bleach stabilisers include ethylenediamine
tetraacetate (EDTA) and the polyphosphonates such as Dequest
(Trade Mark), EDTMP.
However, notwithstanding the above it is preferred for the
composition to contain no bleach and to rely on the improved
clay stain removal derived from the novel hydroxamate and
surfactant combination. This is particularly the case for
liquid compositions.
The detergent compositions may also contain one or more
enzymes. Suitable enzymes include the proteases, amylases,
cellulases, oxidases, peroxidases and lipases usable for
incorporation in detergent compositions.
In particulate detergent compositions, detergency enzymes are
commonly employed in granular form in amounts of from about 0 .1
to about 3.0 wt%. However, any suitable physical form of enzyme
may be used in any effective amount.
Antiredeposition agents, for example cellulose esters and
ethers, for example sodium carboxymethyl cellulose, may also be
present .
The compositions may also contain soil release polymers, for
example sulphonated and unsulphonated PET/POET polymers, both
end-capped and non-end-capped, and polyethylene
glycol/polyvinyl alcohol graft copolymers such as Sokolan
(Trade Mark) HP22. Especially preferred soil release polymers
are the sulphonated non-end-capped polyesters described and
claimed in WO 95 32997A (Rhodia Chimie) .
Product form and preparation
A product according to the invention may take any suitable
form, such as a solid, liquid or paste composition, for example
as particulates (powders, granules), tablets or bars.
Preferably, the product is in a concentrated liquid with a
surfactant concentration of at least 30wt%. Such compositions
require the presence of hydrotropes to solubilise the
ingredients. Ethanol is preferably avoided. Preferred
hydrotropes are propylene glycol and glycerol. Based on this
teaching the skilled person will be able to select other
hydrotropes that avoid the use of highly volatile solvents like
ethanol without the need for inventive activity.
According to a second embodiment of the invention, the
detergent composition is in particulate form. The ratio of
anionic to nonionic surfactant in the detersive surfactant
system is then preferably at least 3:2, preferably at least
7:2.
Powders of low to moderate bulk density may be prepared by
spray-drying slurry, and optionally post dosing (dry-mixing)
further ingredients. Routes available for powder manufacture
include spray drying, drum drying, fluid bed drying, and
scraped film drying devices such as the wiped film evaporator.
A preferred form of scraped film device is a wiped film
evaporator. One such suitable wiped film evaporator is the
Dryex system' based on a wiped film evaporator available from
Ballestra S.p.A. Alternative equipment would be the Chemithon
the Turbo Tube' dryer system wherein a high active surfactant
paste is heated and metering to a multi tube, steam- acketed
drying vessel.
^Concentrated' or 'compact' powders may be prepared by mixing
and granulating processes, for example, using a high-speed
mixer/granulator , or other non-tower processes.
Tablets may be prepared by compacting powders, especially
'concentrated' powders.
The invention will now be further described with reference to
the following non-limiting examples.
EXAMPLES
Measurement of Soil Release Index (SRI)
SRI is a measure of how much of a stain on textile is removed
during a washing process. The intensity of any stain can be
measured by means of a reflectometer in terms of the difference
between the stain and a clean cloth giving * for each stain.
It is defined as * and is calculated as:
= - L'
clean. cloth + (a„ re
- a '
ean . doth )2
+ ( „ ore - bc ' lean_cloth
L*, a*, and b * are the coordinates of the CIE 1976 *, a*, b*)
colour space, determined using a standard reflectometer . *
can be measured before and after the stain is washed, to give
AE* w (before wash) and AE*aw (after wash) . SRI is then defined
as :
S /= 100-AE=
A SRI of 100 means complete removal of a stain.
after wash is the difference in L a b colour space between
the clean (unwashed) fabric and the stain after wash. So a 
after wash of zero means a stain that is completely removed.
Therefore, a SRI aw (aw: after wash) of 100 is a completely
removed stain. The clean (or virgin) fabric is an "absolute
standard" which is not washed. For each experiment, it refers
to an identical piece of fabric to that which the stain is
applied. Therefore, its point in L a b colour space stays
constant .
Determination of SRI-values
For the determination of the SRI-values, a standard protocol
was used, called the Tergometer wash protocol.
Said Tergometer wash protocol is as follows:
1 . Measurement of the colour of the stain on the textile cloth
(before washing) .
2 . Switch on the Tergometer and set to a temperature of 30 °C.
3 . Add water of required hardness, leave to heat to 30°C for 10
minutes .
4 . Add formulation to each pot and then agitate at 100 rpm for
1 minute
5 . Add the stained swatches and ballast into each pot.
6 . Start the wash, agitate at 100 rpm and leave to wash for 12
minutes .
7 . Rinse with fresh water (26°FH) for 2 minutes.
8 . Repeat rinse.
9 . Dry overnight in the dark.
10. Read stains after wash.
Example 1 : Removal of a range of red mud on knitted polyester
and woven cotton
Six liquid formulations were formulated.
The surfactants were sodium alkyl benzene sulphonate (Na LAS
anionic) , alcohol ethoxylate (non-ionic C12 -7EO, Neodol 25-7 ex
Shell) and a neutralised saturated soap (coco fatty acid -
Prifac-5908 ex Uniqema) , as shown in Table 1 at the indicated
concentrations. Also used were standard compounds of a laundry
liquid builder (sodium citrate) , buffer and sequestrant
(Dequest 2066 phosphonate) and enzyme (Savinase Ultra 16L
protease) , The pH of these formulations was buffered to between
7 and 8 . The formulations were made using demineralised water.
Table 1 : Formulations used
The liquid formulations shown in Table 1 were used to remove
red mud stains on knitted polyester and woven cotton in a
Tergometer wash protocol as described hereinabove. In all cases
the product dose was 12 grams/litre.
The level of surfactants and hydroxamates in the Tergometer
protocol are shown in Table 2 .
Table 2 : Surfactant and Hydroxamate levels in the Tergometer
protocol
The results obtained for the removal of red mud stains on
knitted polyester and woven cotton are shown in Table 3 .
Table 3 : Stain removal index (SRI) for Red mud stains on
knitted polyester and woven cotton (Tergometer wash protocol)
These results show that the use of the hydroxamate salts
included in formulations 2-6 leads to better removal of red mud
from both knitted polyester and woven cotton.
Example 2 : Removal of a range of red mud on knitted polyester
(Hydroxamate level less than or equal to 0.05% in product)
Three liquid formulations were formulated.
The surfactants were sodium alkyl benzene sulphonate (Na LAS
anionic) , alcohol ethoxylate (non-ionic C12 -7EO, Neodol 25-7
ex Shell) and a neutralised saturated soap (coco fatty acid -
Prifac-5908 ex Uniqema) , as shown in Table 4 at the indicated
concentrations.. Also used were standard compounds of a laundry
liquid builder (sodium citrate) , , buffer and sequestrant
(Dequest 2066 phosphonate) and enzyme (Savinase Ultra 16L
protease) , The pH of these formulations was buffered to between
7 and 8 . The formulations were made using demineralised water.
Table 4 : Formulations used
The liquid formulations shown in Table 4 were used to remove
red mud stains on knitted polyester in a Tergometer wash
protocol as described hereinabove. In all cases the product
dose was 5.6 grams/litre.
The level of surfactants and hydroxamates in the Tergometer
protocol are shown in Table 5 .
Table 5 : Surfactant and Hydroxamate levels in the Tergometer
protocol
Table 6 : Stain removal index (SRI) for Red mud stains on
knitted polyester and woven cotton (Tergometer wash protocol)
These results show that the use of the hydroxymate salts
included in formulations 8&9 leads to better removal of red mud
from knitted polyester.
Claims
1 ) A laundry detergent composition comprising
a ) 0.005 to less than 0.5 wt% hydroxamic acid or its
corresponding hydroxamate of the structure:
R
wherein R is
a straight or branched C 4- C 2 0 alkyl, or
a straight or branched substituted C 4- C 2 0 alkyl, or
a straight or branched C 4- C 2 0 alkenyl, or
a straight or branched substituted C 4- C 2 0 alkenyl, or
an alkyl ether group C¾ ( CH2 ) n (EO) m wherein n is from 2 to 2 0
and m is from 1 to 12, or
a substituted alkyl ether group CH3 (CH2)n (EO) m wherein n is
from 2 to 2 0 and m is from 1 to 12, and
the types of substitution include one or more of -N¾, -OH,
C OH
II I
- C - N
-S-, -0-, -COOH, and
and R2 is selected from hydrogen and a moiety that forms part
of a cyclic structure with a branched R group,
b ) 3 to 80 wt% of detersive surfactant system comprising
(i) anionic surfactant; and
(ii) nonionic surfactant,
wherein the ratio of (i) to (ii) lies in the range 1:1.1 to
19:1, and
wherein the weight ratio a ) to b ) lies in the range 1 : 6 to
1:16000, preferably 1:10 to 1:400, more preferably 1:20 to
1:100, and
c ) optionally, other ingredients to 100 wt% provided that
zeolite and phosphate builders are present at less than 5 wt%
and ethanol is present at a level of less than 5 wt%.
2 ) Composition according to claim 1 , wherein R is chosen from
the group consisting of C , C5, , C , Cs, Cg, Cio, Cn, C 12 or
C i4 normal alkyl group and R2 is hydrogen.
3 ) Composition according to claim 1 or 2 , wherein R is a C -i
normal alkyl group.
4 ) A composition according to any of claims 1 to 3 , wherein the
composition comprises detergency builder at a concentration
from 1 to 50 wt%.
5 ) A composition according to any preceding claim which
comprises at least 2 0 wt% of the detersive surfactant
system, preferably at least 30 wt% and more preferably over
40 wt%.
6 ) A composition according to any preceding claim which
comprises from 1 to 15 wt% soap, preferably made from
saturated fatty acids.
7 ) A composition according to any preceding claim comprising at
least 0.5 wt% of soil release polymer.
8 ) A composition according to any preceding claim comprising at
least 0.5 wt% anti redeposition polymer.
9 ) A composition according to any preceding claim wherein the
weight ratio of hydroxamate to detersive surfactant system
lies in the range 1:10 to 1:400, preferably 1:10 to 1:100.
10) A composition according to any preceding claim, in which
the ratio of anionic to non-ionic surfactant is 1:1 to 9:1,
preferably 3:2 to 9:1.
11) A composition according to any preceding claim in which the
composition is a liquid composition.
12) A composition according to claim 11, comprising a
hydrotrope system comprising propylene glycol and glycerol
at levels of at least 6 wt%.
13) A composition according to claim 11 or 12, which is a
liquid composition, comprising detersive surfactant at a
concentration from 2 0 to 80% by weight of the total
composition .
14) Use of a composition according to any preceding claim for
removal of particulate soils, preferably red clay, most
preferably Georgia clay, from polyester and cotton fabrics.
15) Use of 0.005 to less than 5 wt% hydroxamic acid or its
corresponding hydroxamate of the structure:
o
wherein R is a C normal alkyl group, and R2 is a hydrogen
atom, in a laundry detergent composition, for improving the
particulate soils stain removal from a textile substrate,
wherein the composition further comprises a detersive
surfactant system comprising anionic surfactant and nonionic
surfactant at a concentration from 3 to 80 wt%; and
optionally other ingredients to 100 wt%.