Note: Descriptions are shown in the official language in which they were submitted.
1 33638~
LIQUID DETERGENT COMPOSITION
TECHNICAL FIELD
The invention relates to pourable, homogenous, aqueous
liquid detergent compositions, especially compositions
containing a water soluble particulate abrasive, which are
suitable for the hand washing of dishes, crockery, cutlery
and saucepans and also for the cleaning of other hard
surfaces such as plastic laminate working surfaces, glass
and ceramic tiles.
BACKGROUND
Liquid detergent compositions for cleaning hard surfaces are
generally classified into two types. The first are aqueous
suspensions conta~ng water-insoluble palpable abrasive
particles: sometimes difficulty can be experienced when
rinsing with water a hard surface that has been cleaned with
such a composition, because insoluble particles of the
abrasive can be difficult to remove completely from the
surface. The second are liquid detergent compositions,
usually containing soap, nonionics and alkyl benzene
sulphonate, but with no palpable abrasive particles.
Liquid detergent compositions of the latter type, although
free from the possible problem of scratching in use,
nevertheless suffer from a number of drawbacks which can
limit their consumer acceptability. They can, for example,
have poor cle~n~ng performance on stubborn soil, especially
in areas where the water is hard, due to the absence of an
abrasive constituent. Also, they can suffer from poor
homogeneity and can possess viscosity characteristics which
are not ideal for use by the consumer. Moreover, the higher
surfactant concentration necessary for in-use removal of
grease and fatty soils can lead to excessive suds formation,
which requires rinsing and wiping by the user. Although
excessive suds production can be controlled to some extent
by incorporation of a suds-regulating material such as
solvents, hydrophobic silica and/or silicone or soap, this
_ 2 l 336386
ln ltself can ralse problems of poor product stability and
homogeneity, and problems associated wlth deposltion of
insoluble residues on the items or surfaces being cleaned,
! leading to residual streaks and spots when dr~ed.
It has been proposed in US Patent No. 4 057 506 (Colgate
Palmolive Company) to employ ln a heavy-duty liquid
detergent composition a builder salt such as a water-soluble
phosphate, silicate, borate, carbonate, bicarbonate or
citrate in a manner such that the composltion is
10 substantially devoid of any builder salt in the form of
solid particles, the composition being otherwise smooth and
creamy. It is however an essential feature of the Colgate
Palmolive's composition that any of the builder salt that is
present in solid form is of colloidal-size particles having
a particle size of <1~, usually <O.l,u.
It would appear that builder salt particles of this
dimension, while possibly functioning as a builder, are too
small to function as an abrasive. Such compositions are
accordingly ineffective in cleaning heavily soiled hard
surfaces as they lack scouring ability.
.
It has been proposed ln GB-A-1370377 to incorporate water-
soluble salt in an essentially non-aqueous liquid
composition, so that the salt remains undissolved and can
act as an abrasive.
25 It has also been proposed in EP-A-0 193 375 (Unilever) to
employ a water-soluble salt such as sodium bicarbonate in
the form of undissolved particles having a mean particle
diameter of from 10 to 500~m suspended in an aqueous
detergent composition which is then suitable for cleaning
hard surfaces. The sodium bicarbonate is intended to be of
a suitable size to act as an abrasive, yet the composition
is characterised by low soil redeposition and little or no
propensity to causing streaking or spotting on surfaces
washed therewith. This is apparently due to the ability of
3 1 33638b
residusl partlcles of sodlum blcarbonate to dlssolve ln
excess water used to rlnse the cleaned surface.
Experience has however shown that although sodium
bicarbonate when employed as described in EP-A-O 193 375
performs as an excellent cleaner, the composition usually
feels slimy to the touch and accordingly when used in the
hand w~sh~ng of hard surfaces, such as dishes, cutlery and
saucepans and the like without the use of gloves, it
produces an unpleasant skin feel sensation sufficient to
persuade the user to seek an alternative product.
Investigations have now shown that this undesirable property
is due to the alkaline pH of the composition of 8.5 or
higher, which is unavoidable when sodium bicarbonate is used
in an amount sufficient to act as the sole water-soluble
abrasive.
In our search for an alternative abrasive having water
solubility and abrasive properties similar to sodium
bicarbonate, but without the undesirable properties
associated with such p~oducts, a large number of materials
were examined.
Eventually it was discovered that potassium sulphate
possessed the requisite abrasive properties and water
solubility, and also it could be formulated into stable
products having a neutral or slightly acid pH, which
surprisingly possessed none of the unpleasant and
unacceptable feel characteristics associated with similar
product containing sodium bicarbonate.
DEFINITION OF THE INVENTION
Accordingly, the invention provides a pourable, homogeneous,
abrasive, aqueous detergent composition, comprising, in
addition to water:
i) detergent active;
ii) water soluble salt, at least part of which is potassium
4 ~ 33638~
sulphate, present ln both a dissolved and an
undissolved ~tate, the undissolved part of the
potasslum sulphate having a mean particle diameter of
from 10 - 500 ~m;
the composition having a pH value not in excess of pH 8, and
an apparent viscosity at 20C of at least 6500 Pas at a
shear rate of 3 x 10- 5 sec~l and not more than 10 Pas at a
shear rate of 21 sec~1.
Compositions of this invention possess suitability for hand
dishwashing and/or cleaning other hard surfaces. Generally
the compositions will be applicable in both ways and are
thus dual purpose although not usually optimum for both
applications. A composition can be formulated to be
principally a hand dishwashing product, in which case it
would have a fairly high level of detergent active with a
low level of abrasive. Alternatively a composition can be
formulated to be principally suitable for cleaning fixed
hard surfaces and removing stubborn soils, in which case it
would have a fairly high level of abrasive with a low level
of detergent active.
DISCLOSURE OF THE INVENTION AND EMBODIMENTS THEREOF
Deterqent Active Compound
The composition according to the invention will comprise
detergent active. Suitably this is chosen from synthetic
anionic detergent actives, and optionally also nonionic
detergent actives.
Suitable synthetic 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 sulphuric acid ester radicals and
mixtures thereof. Examples of synthetic anionic detergents
are sodium and potassium alkyl sulphates, especially those
obtained by sulphating the higher alcohols produced by
reducing the glycerides of tallow or coconut oil; sodium and
~ . . . .
1 336386
potassium alkyl benzene sulphonates such as those in which
the alkyl group contains from 9 to 15 carbon atoms, 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 from 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 ammonium and substituted ammonium
(such as mono, di and triethanolamine), alkaline metal (such
as sodium and potassium) and alkaline earth metal (such as
calcium and magnesium) salts of higher alkyl benzene
sulphonates, higher alkyl sulphonates, higher alkyl alpha-
olefin sulphonates, higher alkyl sulphates, higher alkyl
ether sulphates and mixtures thereof. Higher alkyl aromatic
sulphonates may in particular be higher alkyl benzene
sulphonates cont~n~ng from 6 or 8 to 20 or 22 carbon atoms
in the alkyl group in a straight or branched chain.
Particularly preferred mixtures of anionic detergent actives
comprise (i) sodium alkyl benzene sulphonate and sodium
lauryl ether sulphate (2E0 to 8E0) and (ii) sodium secondary
alkyl sulphonate with sodium lauryl ether sulphate.
The amount of synthetic anionic detergent active to be
employed in the detergent composition of this invention will
generally be from 1 to 40%, preferably from 2 to 25%, and -
most preferably from 2 to 20% by weight.
.. . . .
1 336386
Suitable nonionic detergent active compounds can be broadly
described as compounds produced by the c~nden~tlon of
alkylene oxide groups, which are hydrophilic in nature, with
an organic hydrophobic compound which may be aliphatic or
alkyl aromatic in nature. The length of the hyd,ophilic or
polyoxyalkylene radical which is condensed with any
particular hydrophobic group can be readily ad~usted to
yield a water-soluble compound having the desired degree of
; balance between hydrophilic 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 15 moles of ethylene oxide per
mole of coconut alcohol: condensates of alkylphenols whose
alkyl group contains from 6 to 12 carbon atoms with 5 to 25
moles of ethylene oxide per mole of alkylphenol; condensates
of the reaction product of ethylenediamine and propylene
oxide with ethylene oxide, the condensates containing from
40 to 80% of polyoxyethylene radicals by weight and having a
molecular weight of from 5,000 to 11,000: tertiary amine
oxides of structure R3N0, where one group R is an alkyl
group of 8 to 18 carbon atoms and the others are each
methyl, ethyl or hydroxyethyl groups, for instance
dimethyldodecylamine oxide; tertiary phosphine oxides of
structure R3P0, where one group R is an alkyl group of from
10 to 18 carbon atoms, and the others are each alkyl or
hydroxyalkyl groups of l to 3 carbon atoms, for instance
dimethyldodecylphosphine oxide; and dialkyl sulphoxides of
structure R2S0 where the group R is an alkyl group of from
10 to 18 carbon atoms and ther other is methyl or ethyl, for
instance methyltetradecyl sulphoxide; fatty acid
alkylolamides; alkylene oxide condensates of fatty acid
alkylolamides and alkyl mercaptans.
Mixtures of two or more of nonionic detergent actives can be
employed in the detergent composition of the invention.
. ~ . .. . . . .
- 7 ~ 3363~6
The amount o~ nonionic detQrgent activs that can
optionally b~ ~mployed in the detergent composition o~
the invention will g~nerally be ~rom 0.5 to 15%,
preferably from 1 to 10%, and mo6t preferably from 1 to
8% by weight.
When both anionic and nonionic detergent actives are
employed, the weiqht ratio of anionic detergent to
nonionic detergent active can v~ry but i8 preferably ln
the range of from 1:9 to 9:1, ideally from 1:4 to 4:1.
Preferably, the compositions contain an amount of both
the anionic and the nonionic detergent active which is
chosen so as to provide a ctructured liquid detergent
composition, i.e. one which is 'self' thickened without
necess~rily employing any thicken~ n~ agent per se.
According to an embodiment illustrating this aspect of
the invention, the detergent compositions will comprise
fro~ 2 to 16% by weight of a water-soluble, synthetic
anionic sulphated or sulphonated detergent salt
contA~tng an alkyl radical having from 8 to 22 carbon
atoms in the molecule, and from 0.5 to 4% by weight of
an alkyl~neQYylated nonionic detergent derived from the
cond~nc~tion of an aliphatic alcohol having from 8 to 22
carbon atoms in the molecule with ethylene oxide, such
that the conAen~te has from 2 to 15 moles of ethylene
oxide per mole of aliphatic alcohol.
It is also possible optionally to include amphoteric ,
cationic or z~itterionic detergent actives in the
compositions according to the invention.
Suitable amphoteric detergent-active compounds that
optionally can be employed are derivatives of aliphatic
secondary and tertiary amines contA~n~ng an alkyl group
of 8 to 18 carbon atoms and an aliphatic radical
substituted by an anionic water-solubilising y-o~, for
.
8 1 336386
lnat~nce sodlum 3-dodecylamlneoproplonate, sodlum 3-
dodecylamlnopropane sulphonate and ~odium N-2-
hydroxydodecyl-N-methyltaurate.
Sultable cationlc detergent-actlve compounds are
guaternary ammonium salts haYing an allphatlc radical of
from 8 to 18 carbon atoms, for lnstance cetyltrlmethyl
ammonlum bromide.
Suitable zwltterionic detergent-active compounds that
optionally can be employed are derivatives of aliphatic
quaternary ammonium, sulphonium and phosphonium
compounds having an aliphatic radical of from 8 to 18
carbon atoms and an aliphatic radical substituted by an
anionic water-solubilising group, for instance
3-(N,N-dlmethyl-N-hexadecylammonium)propane-l-sulphonate
betalne, 3-(dodecylmethyl sulphonium) propane-l- -
sulphonate betaine and 3-(cetylmethylphosphonium) ethane
sulphonate betaine.
Further examples of suitable detergent-active compounds
are compounds commonly used as surface-active agents
given in the well-known textbooks NSurface Active
Agents", Volume I by Schwartz and Perry and "Surface
Active Agents and Detergents", Volume II by Schwartz,
Perry and Berch.
The total amount of detergent actlve compound to be
employed in the detergent composition of the invention
will generally be from 1 to 40%, preferably from 1.5
to 30%, more preferably 2 to 20 or 25% by weight.
The Water-soluble Salt
The composition according to the invention will also
- compri~e at least one water-soluble salt, namely
potassium sulphate, which can function as an
abrasive. This salt will be present in the composition
in an amount in excess o its saturation solubility, and
will accordingly be present in both a dissolved and an
9 1 336386
undissolved state. The composltlon wlll therefore comprlse
a saturated aqueous solution of potasslum sulphate together
wlth from 0.5 to 60% more preferred from 1-50% by welght of
the composltlon at 20C ln the form of a solld phase
- 5 comprising particles of the salt havlng a mean particle
diameter of from 10 to 500~m preferably from 20 to 300~m, to
provide the necessary abraslve properties.
The water-soluble salt potassium sulphate is anh~dLous and
does not change into any hydrated species when present as a
crystalline solid in water at a temperature of from 10C to
40C in an amount in excess of that required to form a
saturated solution. The saturation solubility of the salt
in water at 40C is less than twice that at 10C. These
properties help to ensure that the characteristics of the
product, in particular the size, shape and amount of
crystalline abrasive particles, do not change significantly
over the normal temperature range of use. Uniformity of
performance is accordingly ensured. These properties of
potassium sulphate also help to ensure that when the
composition is self structured - that is to say the
structure which provides the desired viscosity
characteristics is derived from an appropriate choice of
anionic detergent active(s) or anionic and nonionic
detergent actives - it will remain stable without
substantial change in viscosity.
The water-soluble salt potassium sulphate has a Mohs
hardness of about 3, which provides useful abrasive
properties. It has a saturation solubility in water which
at 10C does not exceed 15% by weight, so allowing the
presence of undissolved particles at reasonable total
inclusion levels.
The salt also has a solubility in water of more than
5 g/l at 10C, which ensures that any surplus salt can
readily be rinsed from a hard surface after cleaning with
the composition. In this way, the surface can be free from
.
1 336386
' - 10
residual spotCi or strea~s.
The total amount of the potassium sulphate present in the
detergent composltion, both in dlssolved and undissolved
form, should preferably be from 2 to 65~, more preferably
5 from 4 to 55%, and ideally 7 to 50% by welght. Dependent on
the specific abrasive level required, from 0.5 to 60%, more
preferably from 1-50% by weight of the water-soluble salt
should be present in the composition, at normal storage or
use temperatures of from 10 to 40C, in a solid,
particulate form, having an average particulate size, and
other characteristics, as herein defined.
In addition to potassium sulphate, the composition according
to the invention can also optionally comprise other water-
soluble salts such as sodium bicarbonate, sodium chloride,
potassium chloride, magnesium chloride, calcium chloride,
sodium tripolyphosphate pentahydrate, sodium tetraborate
decahydrate and sodium citrate, provided that the pH value
of the composition does not exceed pH 8. With this proviso,
it is furthermore also posssible to use other water-soluble
inorganic salts or organic salts of lithium, magnesium,
sodium, potassium and calcium, which salts can possibly
function as builders and abrasives. Specific examples are
sodium oxalate, sodium succinate, sodium adipate and sodium
glutarate. Mixtures of such salts can be employed. The
presence of electrolytes which are capable of slightly
reducing the solubility of potassium sulphate in water is
preferred. Especially suitable in this respect is the
incorporation of alkali metal chlorides, preferably sodium
chloride, at a level of from 0.5 to 5~, or higher, up to
10~, of the composition. This effects a small reduction of
the solubility of potassium sulphate in water, thereby
reducing the required amount of potassium sulphate for
obt~ining an adeguate level of undissolved particles, but at
the same time does not reduce the solubility of potassium
sulphate to below a level of 5 g/litre, thereby ensuring
that any surplus salt can readily be removed from a hard
.. . _ , . . . .
11 1 3363~6
surface after cleAni n~.
- The presence of electrolytes, especlally sodium chloride, is
also advantageous in that the freeze-thaw stability of the
product is im~o~ed.
Especially advantageous ls the incorporation of another
electrolyte additionally to the alkall metal chlorides, this
additional electrolyte is preferably an alkali metal citrate
such as sodium citrate, which provides the additional
benefit of pH regulation.
It is preferred that the total amount of water-soluble salt,
including potassium sulphate, is at least 9% by weight of
the composition. It may lie in the range from 9 to 50% by
weight.
Water
The composition according to the invention will also
comprise water which will generally form from 30 to 89.5~,
preferably from 40 to 80%, and ideally 45 to 70% by weight
of the composition.
Optional Ingredients
The composition according to the invention can contain other
ingredients which aid in their cleaning performance,
provided that due to the presence of these other ingredients
the pH value of the composition does not exceed pH 8. For
example, the composition can contain detergent builders such
as nitrilotriacetates, polycarboxylates, citrates,
dicarboxylic acids, water-soluble phosphates especially
polyphosphates, mixtures of ortho- and pyrophosphate and
mixtures thereof. Such builders can additionally function
as abrasives if present in an amount in excess of their
solubility in the overall composition as explained herein.
In general, the builder, when employed, preferably will form
from 0.1 to 25~ by weight of the composition.
I
_ 12 l 3363~6
Metal lon egueotrants such a-
thylenediauinetetraacetate~, amlno-polyphosphonates
~ S.) and phosph_te~ and a wlde varlety of other
S poly-functlonal organlc acld~ and ~alt~, can also
optlonally be employed.
A further optlonal i..y-ediQnt for compo6itlon~ according
to the lnventlon 18 a suds regulating material, whlch
can be employed ln composltlons accordlng to the
lnventlon whlch have a tenA~cy to produce excessive
suds in use. One example of a suds regulating material
is 60ap. Soaps are salts of fatty acids and include
alkali metal soaps such as the sodium, potassium,
ammonlum and alkanol ammonlum salt~ of higher fatty
aclds contalnlng from about 8 to about 24 carbon atoms,
and preferably from about lO to about 20 carbon atoms.
Particularly useful are the ~odium and potasslum and
mono-, di- and triethanolamine salts of the mlxtures of
fatty aclds derived from coconut oil and ground nut oil.
When employed, the amount of soap can from at least
0.005%, preferably 0.5% to 2% by welght of the
composition. A further example of a suds regulating
material ls an organic solvent, hydrophobic sllica and a
silicone oil or hydrocarbon~.
The compositions according to the invention may
optionally contaln structurlng agents to ald in
provlding appropriate rheological properties to maintain
the llnA ~olved salt or salts uniformly distributed in
the composition and in ~nhA~cing their distribution and
adherence of the composition to the hard surface to be
cleaned. Preferred structuring agents include
polysaccharides, such as sodium carboxymethyl cellulose
and other chemically modified cellulose materials,
xanthan gum and other non-flocculating structuring
agents such as 8iopolymer PS87 referred to in US Patent
No. 4 329 448. Certain polymers such as a polymer of
acrylic acid cross-linked with a poly functional agent,
C A 1 ~ 3 6 3 86
13
for example *CARBOPOL, can also be used as structuring agents. The
amount of such structuring agents, when employed, to be used in
compositions according to the invention can be as little as 0.001%, preferably
at least 0.01% by weight of the composition.
The compositions according to the invention can also comprise at least
partially esterified resin such as an at least partially esterified adduct of rosin
and an unsaturated dicarboxylic acid or anhydride, or an at least partially
esterified derivatives of co-polymerisation products of mono-unsaturated
aliphatic, cycloaliphatic or aromatic monomers having no carboxy groups and
unsaturated dicarboxylic acids or anhydrides thereof.
Typical examples of suitable copolymers of the latter type are copolymers of
ethylene, styrene, and vinylmethylether with maleic acid, fumaric acid, itaconic15 acid, citraconic acid and the like and the anhydrides thereof. Preferred are
the styrene/maleic anydride copolymers.
In general, the compositions of the invention can optionally comprise from
0.005 to 20%, usually from 0.1 to 15% and preferably from 0.5 to 10% by
20 weight of the at least partially esterified resin.
Compositions according to the invention can also contain, in addition to the
ingredients already mentioned, various other optional ingredients such as pH
regulants, perfumes, colourants, optical brighteners, soil suspending agents,
25 detersive enzymes, compatible bleaching agents, gel-control agents, freeze-
thaw stabilisers, bactericides, preservatives, detergent hydrotropes, opacifiersand solvents.
The compositions according to the invention will not contain more than 10%,
30 preferably not more than 5% by
C~ 1 336386
14
weight of a water-insoluble abrasive, such as felspar and quartz, in view of
the tendency of such abrasives to leave a deposit on hard surfaces after
cleaning, even when rinsed with water.
Ideally, compositions according to the invention are substantially free from
water-insoluble abrasives.
Generally, the water and optional ingredients comprising other detergent
adjuncts will form the balance of the composition, after accounting for the
detergent active compound and the water-soluble salt ingredients.
Accordingly, the water and optional ingredients can form from 89.5 to 25% by
weight of the composition.
e~
It is an important feature of the invention that the compositions area
formulated so as to have a pH value which does not exceed 8. Preferably
the composition have a pH value of from 5 to 8, ideally about pH 6-7,
although pH values of as low as 3 are acceptable.
Suspending Properties
It is an important feature of the invention that the composition will be capableof suspending the undissolved particles of salt abrasive, so that the consumer
does not need to agitate the composition, for example by shaking it, in order
to re-suspend and re-distribute sedimented particles prior to use. For this
purpose, the composition should preferably have an apparent viscosity at
20C of at least 6500 Pas at a shear rate of 3 x 10 sec. to ensure that
the particles of salt abrasive do not sediment on standing at 20C by more
than 1 cm in one month. Ideally, the apparent viscosity at 20C is at least
25,000 Pas at a shear rate of 3 x 10 5 sec.
C~ 1 336386
This viscosity value can be determined by application of Stokes Law, with the
assumption that the particles of salt abrasive are spherical, and that the
above sedimentation rate applies.
While it is necessary to ensure that the composition according to the invention
has an apparent viscosity which is high enough to prevent any substantial
settlement of the undissolved particles of salt abrasive during storage, it
should remain fluid, so that it can readily be poured from a bottle or other
container when required for use. For this purpose, the composition should
have an apparent viscosity at 20C, measured using a rotational viscometer
which does not exceed 10 Pas at a shear rate of 21 sec. 1. Preferably, the
apparent viscosity at 20C is no greater than 5 Pas at a shear rate of 21
sec
Suitable rheological conditions to suit these criteria can be provided by
judicial choice of anionic and nonionic detergent to provide a structured liquidhaving the requisite suspending properties, and/or by use of an appropriate
amount of an alternative structuring agent such as is described herein.
A preferred method for adapting the viscosity of the composition is by the
inclusion of water-soluble polymers into the system, such as for instance
described in our co-pending Canadian application 572,952.
Process for Preparation of ComPositions
Since the compositions according to the invention are in liquid form, they can
be prepared simply by blending the essential and optional ingredients in
water.
Packaging and Use of the Compositions
The compositions according to the invention are pourable liquids that are
preferably contained in a closable
