Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
1~72~3~ -
LIQUID DETERGENT CO~lPOSITIONS
,
Field OL the Invention
- . This inventi.on relates to a~ueous liquid dishwashing
: detergent compositions and especially to substantially
unbuilt hand dishwashing detergent compositions incorpora~ing
alkane sulphonate surfactant together with a source.o
magnesium ions.
~ ~ Background of the Invention
::~ The use of.magnesium salts and magnesium surfactants
such as alkyl sulphates; alkyl ether sulphate;s and alkyl
~benzene sulphonates in dishwashing detergent formulations
: : is knownr and.British Patent Specification Nos~. 1,5~4,441,
1,551-,074 and 2,010,893A are representative disclosures
of the sta~e of the art.~ The art teaches that thes~
formulations have enhanced performance, particularly when
used in water of low mineral hardness. Liquid detergent
compositions containing alkane sulpho~at~sur~ac.~an~s are
also known in the art.~ Compositions~primarily intended
for fabric washing are described:ih~B;.P. 1,054,217,
~ 1,329,508 and 1,291~l63/ th~ last named of which disclose~s
: ~0 a mixture o~ an alkane sulphonate, an ethox~lated alXyl
; : su~phate, and a proteolytic enzyme together with an
en2yme~s.tab;1ising aqent in the form of a calci.um or
magnes~um salt, specifi.cally the:ac.etate or t~e chlori~
Enzymes are not however customary:components of hand
dishwashing liquid detergent formulations, particularly
: . in formulations where skin mildness is an importan~
~ in-use requirement.
; Dishwashing liquid detergent compositions contaîning
alkane sulphonates are also kno-~n, e~amples of such
30 :disclosures including those in B.P. l,339,069, l,382~295,
1,451,228 and l,567,q21. However products mad-e in
,' . ' , '
~L7;~
-- 2 -- .
accordance with these teachings have all been found to
be non-optimal in one area of performance or another eg.
raw material cost, phase stability on storage, sudsing in
water of high or low mineral hardness, effect on hands,
suds profile, physical stability under cyclic temperature
conditions etc ..
The present invention.is concerned with an aqueous
hand dishwashing detergent composition that is enz~me- -
free. More particularly, it co~cerns an enz~me-free
dishwashing detergent composition containing alkane
sulphonate surfactan~, the sudsing performance of which
has been enhanced by the incorporation of speci~ic levels
of magnesium ion. - .
According to the present invention there is provided
a clear single-phase enzyme-free dishwa~hing liquid -
composition comprising 20-40% of a C14-C17 alkane 5ul-
phonate, 5-15% of an anionic surfactan:~ selected from .. . water soluble C10-Cl6 alkyl ethoxy sulphates containin~
from 1-6 ethoxy groups per mole of alkyl sulphate, and
mixtures thereof with water soluble C10-Cl6 alkyl ben2en~
sulphonate~, 0-5% of a suds boosteL sel.ected from C10-Cl6
k 1 mides C C16 alkyl C2-C3 alkanol 10 16
alkyl di Cl-C3 alkyl or di C2-C3 hydroxyalkyI amine oxiaes
and from 0.35%-0.7% magnesium ion, the composition containing
`5 no more than 1.75~ by weight of chloxide ions or more:
thanØ35% by weight of inorganic sulphate ions provided
that whexe chloride ions are also present ~he level of
sulphate ions should not exceed 0.25~ by weight, the
counter ions other than magnesium necessary to provide
a pH of 6.0-7.5 being selected from sodium, potassium,
ammoni~m and alkanolammonium.
- Preferably the composition comprises 22-36-~ C16 17
alkanesulphona.te,6-12% C12 14 alkyl ethoxy sulphate and O.S~
magnesi~m ion with a ma~im~m o~ 0.5% inorganic sait anions.
Secondary alkane sulpho~ates use~ul in the pr~sent
invention preferably have from 13 to 18 caxbon atoms per
1172~3C~
.
molecule, and most desirably 13 to 15, and are characterised
by a high solubility in water compared to alkyl aryl
sulphonates and other sulphuric acid reaction products
used for dishwashing detergent compositions. These
S sulphonates are preferably prepared by subjecting a cut
of paraffin, corresponding to the chain lengths specified
above, to the action of-sulphur dioxide and oxygen in
accordance with the well-known sulphoxidation process.
The product of this reaction is a secondary sulphonic
10 acid which is then neutralized with a suitable base to
provide a water-soluble secondary alkyl sulphonate.
Similar secondary alkyl sulphonates may be obtained by
other methods, e.g. by the sulphochlorination method in
which chlorine and sulphur dioxide are reacted with
~5 paraffins in the presence of actinic light, the resulting
sulphonyl chlorides being hydrolyzed and neutralized to
form the secondary alkyl sulphonates. Whatever technique
~ ~ is employed, it is normally desirable to produce the
sulphonate as the monosulphonate, having no unreacted
starting hydrocarbon or having only a limited proportion
thereof present and with ~ittle or no inorganic salt by-
product. Similarly, the proportions of disulphonate or
higher sulphonated material will be minimized but some
may be present. The monosulphonate may be terminally
sulphonated or the sulphonate group may be joined on the
2-carbon ox other carbon of the linear chain. Similarly,
any accompanying disulphonate, usually produced when an
excess of sulphonating agent is present, may have th~
sulphonate groups distributed over different carbon atoms
~0 of the paraffin base, and mixtures of the monosulphonates
and disulphonatzs may be pxesent.
Mixtures of monoalkane sulphonates wherein the alkanes
are of 14 and 15 carbon atoms are particularly preferred
wherein the sulphonates are present in the weight ratio
of C14 to Cl~ paraffins in the range from 1:3 to 3:1,
L7~3~
-- 4
preferably 1:2 to 2:1. Surprisingly, this particular
mixture produces detergents which clean dishes better and
which suds longer, especially in hard water, than other
mixtures of paraffin sulphonates, e.g. those of 13 to 17
carbon atoms. This is also true, to a lesser extent, of
the individual components of the C14 and C15 mixture.
The alkane sulphonates are used at a level of from 20
to 40~, more generally at a level of from 22% to 36%,
preferably from 24% to 34% and most preferably from 26~ to
32~ by weight of the composition.
The alkyl ethoxy sulphates used in the compositions of
the present invention can be represented by the formula
RO(c2H4o)nso3x
where R is a C10-Cl6 preferably 12-15 linear or branched
chain, primary alkyl group, n is a value from 1 to 6 pref-
erably 2-5 and X is a water soluble cation. C10-Cl6
alcohols, derived from natural fats or Ziegler olefin
build-up or OXO synthesis form suitable sources for the
alkyl group. Examples of synthetically derived materials
include Dobano ~ 23 (RTM) sold by Shell Chemicals (UK)
Ltd., Ethy ~ 24 sold by the Ethyl Corporation, a blend
of C13-C15 alcohols in the ratio 67~ C13, 33% C15 sold
under the trade name Lutensol~ by BASF GmbH and Synperonic
(RTM) by IC~ Ltd, and Lial~ 125 sold by Liquichimica
Italiana. Examples of naturally occuring materials from
which the alcohols can be derived are coconut oil and palm
kernel oil and the corresponding fatty acids.
The alkyl ethoxy sulphates are used in an amount of
from 5~ to 15~ by weight of the composition, and, where
they constitute the only anionic surfactant species other
than the alkane sulphonate, are normally used at from 10%
to 15~ by weightO
The alkyl ethoxy sulphates can also be used in
admixture with water soluble linear or branched C10-Cl6
,i
., ~ . .
~172~3(~
alkyl benzene sulphonates. In such alkyl benzene sulphonates,
the alkyl group is preferably linear and contains 11-13 carbon
atoms, a material with an average carbon chain length of 11.8
being most preferred. The phenyl isomer distribution, ie. the
point of attach]nent of the alkyl chain to the benzene nucleus,
is not critical but alkyl benzenes having a high 2-phenyl iso-
mer content are preferred.
Where mixtures of the alkyl ethoxy sulphates and
alkyl benzene sulphonates are used the levels of alkyl benzene
sulphonate should be such that the ratio of the combined weight
of alkane sulphonate and alkyl benzene sulphonate to the weight
of alkyl ethoxy sulphate should not exceed 10:1 and prefer-
ably should not exceed 5:1. In practice the level of alkyl
benzene sulphonate will not usually exceed 12% by weight of
the composition and will normalIy be in the range 4%-10% by
weight. Correspondingly, the overall alkyl ethoxy sulphate
level will be reduced where such mixtures are employed.
An essential component of the formulation is a
source of magnesium ions at a level to provide 0.35% to 0.70%
by weight of magnesium ion in the product, preferably 0.40%
to 0.60~ by weight. Subject to the requirement that the final
product is a clear single-phase liq~id, the magnesium ion can
be provided either by addition of a water soluble magensium
salt such as the chloride or acetate to the formulation, or
by the use of magnesium oxide)or hydro~ide slurry as a com-
ponent of the neutralising medium for one or other of the
anionic surfactants during manufacture.
The requirement that the final product is a clear,
single phase liquid creates a constraint on the level of dis-
solved inorganic salts that can be tolerated by the formula-
tion without phase separation or crystallisation occuring.
By 'tolerated' is meant the ability of a
~17Z13(~
-- 6
formulation to withstand storage without t,he formation
of other solid or li~uid phases~ A minimum requirement
is that storage at ambient temperature (v'iz 20C) should
not result in such phase separation but preferably the
temperature at which phase separation or crystal deposition
, occurs should necessitate cooling of the omposition to
a sub-a~ient temperature. This sub-a~ient temperature
is conventionaIly known as the chill point temperature
of a liquid deter~ent composition and'is defined as that
10 temperature below which solid inorganic crystals separate
from the composi,tion on storage. It has been-found'that,
in order to achieve acceptable chill point temperatures,
the composition of the present invention should not
contain more than 1.75% by weight of chloride ions or
15 more than 0.35~ of sulphate ions, provided that where
' chloride ions are also present the level of sulphate ions
, should not exceed 0.25%'by weight and preferably should
' not ~ceed 0.15%''by weight.' Formulations having low chill
point temperatures, i.e. < ~C, Xave sulphate levels at ',
20 the lower end of this range.
' The'tolerance-of the formulations to inorganic salt
level has been found to be dependent on the inorganic
salt type and also on the counter ion types present in
the formula,tions,. Thus fo~mulations in which the counter
25 ~ons ~other than the magnesium) are mainly or exclusively
ammonium'or potassium are-more tolerant to inorganic -
salts,than those where the cG~nter ions are main~y or
exclusively sodium ions. Furt~er~.~re chloride ions can
be tolerated at much higher levels than sulphate ions,
It has been found, for example, that in a formu-
lation compr~sing
30% MC15-C17 paraffin sulphonate
15% ~C12~E0)3 sulphate
10% ethyl alcohol solvent
with 0.475~ Magnesium ion added as ma~nesium
1~ 2
- 7
hydroxide forming part cf the counter ion M,
when M is ammonium, the level of sulphate ion that the
formulation can tolerate without precipitation is 0.35
by weight of the formulation whereas when M is sodium,
5 the level of sulphate ion that can be tolerated is no
more than 0.20~ by weight. By con-.ràst in the same
system, 1.75% chloride ion can be toleratea, irrespe~tive
of the counter ion e~ployed, althou~h at this level of
chloride ion the presence of sulphate ions in excess o~
io about 0.15% by weight will lead to deposition of a
crystalline precipitate.
~ he commerciai production of paraffin sulphonates,
alkyl benzene sulphonates and al~yl ether sulphates uses
techniques that are well known in the art and involves
15 the use of sulph(on)ating agents such as S03, oleum,
chlorosulphonic acid or S02, all of which gi~e rise to
-- _- residues of sulphates and~or chlorides in the active
materials. The levels of sulphates and/or chlorides can
be minimised by careful control of the sulph(on~ation
20 conditians, and by air, or inert gas, spargi~g of the
acid sulph(on)ate products but in general at least 0~1%
by weight of inorganic sulphate (on a finished product
basis) arise from this source,even under ideal conditions~
Thus, little or no sulphate ion can be~ad~ed to these
25 systems if precipitation is to be avoided, and the
addition of the magnesium ion as magnesium sulphate~ is
not fe~s-ible fr~m a prod~ct st~hility sLc..dpoint
Indeed, the low tole~ance of the c~mpositi~ns ~f
the present invention to inorganic sulphates, produced
- 30 as a ~y-product of the sulph~on)ation process frequently
results in a 'desalting' step being necessary to pr~vide
acceptable product stability on storage. I~here appreci~
able levels of inorganic sulphate are present, such as
the 4-6% by weight of sulphate found in co~ercially
35 available paraffin sulphonates, this 'desalting' step is
. .
- . . : . . .
.
3(~ :
.
essential in order to avoid precipitation and deposition
of inorganic sulphate from compositions in accordance -
with the invention. This desalting step is normally
carried out on the surfactant concerned prior to mixing
with other formulation components and can be per~ormed
' by adding a lower aliphatic alcoho~,such as ethanol or
isopropa~ol to the neut~alised surfa~tant in order to
precipitate the sulphate as a crystalline solid. The
precipitated sulphate is then remoYed by ~iltration or
10 centri~ugation. ' ' - ' ' ''
As no~ea above, the formulations of the present
invention are more tolerant of chloride ions than sul-
phate ions and thus where chloride ions are proauced by
a sulphation by-product, such as in the chlorosulphation
15 of alkyl ethers, subsequent treatment of the surfactant
is normally unnecessary. The level of chloride ion
, arising from this'source is normally of the order of
"- 0.5~ on,a total product weight basis and pre~erred
' formulations, made using S03 su~phonation techniques,
20 are essentially free of chloride ions.
The higheI tolerance of the compositions of the
invention to chloride ions leads ts the situation that
provid~d the system is substantially free of inorganic
sal~s prior to the i~corporation of the magnesium ion,
25,the latter can be incorporated as the c~loride salts.
' In this context 'substantially ~ree' means no more than
0.2~ by weight o~ the com~osition of inorga N c anions.
Pxeferably the compositions contain l~ss than 0.15% by
weight of other inorganic anions when levels of chloride
,, 30 ion in excess of about 1~ by weight are present.'
Nevertheless, the incorporation of a wat~r soluble '
magnesium salt into the formulation, whilst being permis-
sible, is not a preferred technique as it increa$es the
risk of phzse separation or crystalline salt deposition,
35 and, in the case of magnesium chloride, may give rise to
Z~-3~
g
corrosion problems in the processing equi~ment As
noted a~ove, the addition of magnesium sulph2te in an
amount sufficient to provide the benefits of the present
invention causes crystalline salt precipitation. Even
S where a salt such as magnesium acetate is employed as the
source of magnesium ion, its addition to the ~ormulation
may cause sulphate.and chloride salts to precipit~te.,
even though these may only be present at levels which
would otherwise be acceptably low. Accordingly the use ..
10 of magnesium oxide or hydroxide neutralisation of oné .
or more of the anionic surfactant species is a preerred
means o~ introducing the ma~nesium ion into the system.
The othex cations used in the neutralisation of the
anionic surfactants may he sodium, potassium, ammonium
15 or alkanolammonium, but ammonium is a pre~erxed cation
. because of its depressive effect on the chill point -
``. ` . temperat~re of the compositions. Preferrea com~osltions--
have chill points c.oC and in order to-achieve this at
least 50% of the surfactant cations should be ammoniu~ -
2~ ions..
~.- . .A desirable.componen~ of the i~en~ion is a Suas
boosting agent at a level of up to 5%, preferably 3-4~
by weight. .
. The suds-promotins~agent can. be any of C12-C14 mono-
25 and di C2-C3 al~anolamide, C12-Cl~ alkyl ami~es condens~d
........ with up to 15 moles of ethylene oxide per mole of amide
and.tertiary amine oxides containing :a C8-C18 alkyl group.
Examples o~ the alkanol~ides ar.e coconu.~ ~L~yL
- monoetha~olamide, coconut alkyl diethanolamide and-
30 coconut al~yl mono and di isopropanolamides~
: : Examples of the ethoxylated amides include coconut
alkyl amide condensed with six moles of ethylene oxide,
lauryl amide condensed with eight moles of ethylene
oxide, myristyl amide condensed with ten moles oE ~
~5 ethy1ene oxide and coconut amide condensed with eight
.
~7Z~3~1
~ 10 -
moles of ethylene oxide. Amine oxides useful in the
present invention have one alkyl or hydroxyalkyl moiety of
8 to 18 carbon atoms, preferably 8 to 16 carbon atoms and
two moieties selected from alkyl groups and hydroxyalkyl
groups containing 1 to 3 carbon atoms. Examples of such
amine oxides include dimethyloctylamine oxide, diethyl-
decylamine oxide, bis - (2 - hydroxyethyl) dodecylamine
oxide, dimethyldodecylamine oxide, dipropyltetradecylamine
oxide, methylethylhexadecylamine oxide, and dimethyl - 2 -
hydroxyoctadecylamine oxide.
A highly preferred example of the tertiary amine oxideis a C12-C14 alkyl dimethyl amine oxide in which the
Cl2-Cl4 alkyl group is derived from coconut oil.
The balance of the formula comprises a hydrotrope-
water system in which the hydrotrope may be urea, aCl-C3 alkanol, or a lower alkyl benzene sulphonate
salt such as toluene, cumene or xylene sulphonate. The
preferred hydrotrope is ethanol which is employed at from
6% to 10% by weight of the composition preferably at from
7~ to 9%.
Optional ingredients of the liquid detergent compos-
itions of the invention include thickeners such as guar
gum, antibacterial agents such as glutaraldehyde and
Bronopo ~ (RTM), antitarnish agents such as benzoxy-
triazole, heavy metal chelating agents such as EDTA or
EDTMP~ perfumes and dyes. The pH of the compositions
may be anywhere within the range 6-7.5 but as Manufactured
the compositions normally have a pH in the range 6.6-7.3
preferably 6.6-6.9 in order to maintain colour stability.
The technique of incorporation of the magnesium ions
is not thought to be critical and the compositions can be
made in a number of ways. The individual anionic surfac-
tants can be made as aqueous solutions of alkali metal
or ammonium salts which are then mixed togerher with the
hydrotrope, and the suds
~ 7 ~1 3~
booster, if this is included, following which the magnesium
ion can be introduced as a water soluble salt such as the
chloride or acetate. Optional minor ingredients are then
added after which the pH and viscosity is adjusted. This
~ethod has the advantage of utilising conventional techniques
and equipment but results in the introduction of additional
chloride or acetate ions which can increase the chill point
temperature (the temperature at which inorganic salts preci-
pitate as crystals in the liquid).
10 An alternative method is to neutralise the alkyl
ether sulphuric acid or the alkane sulphonic acid with a mag-
nesium oxide or hydroxide slurry which avoids the introduction
of additional inorganic anions. Although not essential, it is
convenient to carry out the neutralisation of the alkyl ether
sulphate in a 'heel' formed by a dispersion of the magnesium
oxide or hydroxide slurry in a mixture of the hydrotrope and
the other surfactant. Any alkyl benzene sulphonate present
in the formulation can be neutralised separately or in the
same 'heel', and the neutralised sulphonate and sulphate sur-
factants together with the hydrotrope are then added to thefinal mixing tank and the suds booster and any optional ingre-
dients added before the pH is adjusted as above.
The invention is illustrated in the ~ollowing
examples in which the percentage of the components are by
weight on the finished composition.
Example l
The following composition was made up
C14-C15 s-alkane sulphonate 35) incorpor+a~ing 0.44
30 C12-C13 alkyl ~EO)3 sulphate 15) p2a21s Mg ion~and
Ethanol 9
Urea 3
Perfume Colour & Miscellaneous
Water 37
100
The C14-C15 s-alkane sulphonate, available as a paste of the
ammonium salt containing 60% active and 4~ ammonium sulphate
was desalted by treating 58.33 parts paste with 9 parts ethan-
ol and filtering off the precipitated ammonium sulphate to
leave G5.23 parts of desalted paste containing 0.23 parts
'~,f'
. ..
` ~72~3(~
- 12 -
ammonium sulphate. This desalted paste was then used as a heel
for the neutralisation oE the alkyl ether sulphùric acid. The
latter was prepared by sulphation of an ethoxylated linear
C12-C13 alcohol using an S03-air mixture and contained 0.46~
H2SO4. 2.12 parts of a 50~ slurry of magnesium hydroxide in
water was added to the paste heel and then the alkyl ether sul-
phuric acid was addcd with agitation. After the neutralisation
of the alkyl ether sulphuric acid the remaining components were
added and the pH was trimmed to 6.8 using ammonium hydroxide or
citric acid. The resulting liquid detergent was a stable clear
liquid with a sulphate content, expressed as (NH4)2SO4, of 0.32
by weight of the composition.
Example 2
Cl4_155~alkane sulphonate 30~ incorpor~at+ing 0.44
C12-C13 alkyl (E0)3 sulphate 10) P1ar93ts Mg iNn +and
15 Linear C11_8alkyl benzene 5)
sulphonate
Ethanol 9
Urea 4
Perfume Colour ~ Miscellaneous
20 Water 41
1 0 0
A similar procedure is followed as for Example 1. The ammon-
ium alkane sulphonate surfactant is desalted to leave 57.2 parts
of paste containing ammonium sulphate and 0.20 parts ammonium
sulphate and the alkyl benzene~ sulphonic acid (produced by
SO3 sulphonation and containing 0.11 parts H2SO4) is added to
this desalted paste. The magnesium hydroxide slurry is then
mixed in followed by the alkyl ether sulphuric acid. When
neutralisation of the latter is complete the pH is brought up
to pH 6.8 with ammonium hydroxide and th~e remainder of the
ingredients added to complete the formulation. The final pro-
duc~ is a clear stable liquid with a sulphate content, express-
ed as (NH4)2 SO4 of 0.43~ by weight of the composition.
Example 3
35 C14-C15s-alkane sulphonate 25) incorpor+a~ing 0.44
C12_13 alkyl(EO)3 sulphate 10) 1-62 parts NH4 ion
Linear C11 8alkyl benzene 5)
sulphona~e
,, ,~
~7~3V
- 13 -
Coconu~ monoethanolamide 3
Ethanol 10
Perfumes Colour & Misc.
Water 46
100
The product is made up of using the procedures of Example 25
2 ~o give a clear liquid having a sulphate content expressed
as (NH4)2S04 of 0.40~ by weight of the composition.
, ~"
