Thickened aqueous detergent compositions with improved cleaning performance with short chain surfactants

The present invention is an aqueous liquid detergent composition comprising a short chain surfactant for improved cleaning performance. Said composition further comprises a mixture of long chain amide oxides to restore viscosity. Said composition provides outstanding soil removal when used as a dish pretreatment composition as well as outstanding cleaning performance when used in hard-surface applications including toilet bowl cleaning.

TECHNICAL FIELD 
The present invention relates to thickened aqueous detergent compositions 
suitable for household application. More particularly, the compositions 
herein are suitable in hard-surface applications including toilet cleaning 
as well as in dishwashing applications, especially as a pretreatment 
composition. 
BACKGROUND OF THE INVENTION 
The liquid detergent compositions comprising the combination of long chain 
amine oxides and fatty acids are well known in the art. 
It is desirable that such compositions have good cleaning properties. 
However, it has been found that long chain amine oxides do not provide the 
optimum cleaning performance. It is thus a first object of the present 
invention to provide cleaning compositions comprising long chain 
surfactants with improved cleaning. 
In response to this object, it has been found that the incorporation of 
short chain surfactants is beneficial and meets this object thereby 
enhancing the cleaning performance. However, it has been observed that the 
incorporation of shod chain surfactants in such compositions results in 
the decrease of viscosity of the composition. Yet, it is considered 
essential that the compositions should exhibit a high degree of viscosity 
so that the compositions adhere to the vertical surfaces and surfaces 
inclined to the horizontal. 
Thus, it is a further object of the present invention to provide a liquid 
composition which comprises long chain surfactants and short chain 
surfactants, which retains viscosity. 
In response to this object, it has been found that viscosity may be 
retained even upon the addition of short chain surfactants, by the use of 
a specific mixture of amine oxides, more specifically a mixture of a 
C.sub.14 chain amine oxide with a C.sub.12 chain amine oxide, or a 
C.sub.16 chain amine oxide or mixtures thereof. 
A further advantage of the present invention is that there is no need for 
an additional thickening agent. An additional advantage of the 
compositions of the present invention is that they have a desirable 
sudsing profile such that suds suppressers are not required. 
Thickening compositions comprising long chain amine oxides and fully 
saturated fatty acids are well known in the art. 
U.S. Pat. No. 4,282,109 discloses a thickened bleach composition comprising 
hypochlorite and linear and branched long chain C.sub.10 -C.sub.18 amine 
oxides as thickeners. There is no mention of short chain C.sub.6 -C.sub.8 
surfactants or fatty acids. 
EP 274 885 discloses thickened bleaching compositions comprising alkali 
metal hypochlorite and straight chain C.sub.14 amine oxide with a mixture 
of branched and straight chain C.sub.15 amine oxide. There is no mention 
of short chain surfactants. The compositions may optionally contain fatty 
acids as an additional thickening aid. 
EP 233 666 discloses a process for the manufacture of a thickened bleaching 
composition comprising hypochlorite, a hypochlorite-soluble surfactant and 
an alkali metal salt of a fatty acid. The detergent actives include amine 
oxides, preferably lauryldimethylamine. There is no mention of short chain 
surfactants. 
DE 28 37 880 discloses bleaching compositions comprising alkali metal 
hypochlorite and mixtures of branched and linear amine oxides of varying 
chain length, (C.sub.5 -C.sub.17) for increased viscosity. The 
compositions do not require fatty acids for thickening. 
EP 30 401 discloses thickened bleaching compositions comprising 
hypochlorite and a certain number of product characteristics including pH 
and viscosity. Mixtures of C.sub.8 -C.sub.18 amine oxides and fatty acids 
are preferred as thickening agents. There is no mention of short chain 
surfactants. 
SUMMARY OF THE INVENTION 
The compositions of the present invention comprise aqueous compositions 
having a viscosity of from 50 cps to 2000 cps comprising a mixture of long 
chain amine oxides according to the formula R.sub.1 R.sub.2 R.sub.3 NO 
wherein R.sub.2 and R.sub.3 are independently C.sub.1 -C.sub.3 alkyl 
groups, and a short chain surfactant. 
Said short chain surfactant comprises a hydrophobic portion and a 
hydrophilic portion, wherein the chain length of said hydrophobic portion 
is C.sub.6 -C.sub.10. 
Said mixture of long chain amine oxides comprises a first amine oxide 
wherein R.sub.1 is a C.sub.14 alkyl group and a second amine oxide wherein 
R.sub.1 is a C.sub.12 alkyl group or a C.sub.16 alkyl group, or mixtures 
thereof of said amine oxides. 
The ratio of said first amine oxide to said second amine oxide wherein 
R.sub.1 is a C.sub.12 alkyl group is from 0.3 to 10, and the ratio of said 
first amine oxide to said second amine oxide wherein R.sub.1 is a C.sub.16 
alkyl group is from 0.2 to 4.5. 
All ratios, percentages and parts given herein are by % weight of the total 
composition unless otherwise specified. 
The present invention further encompasses a process of treating dishes, 
wherein said dishes are contacted with a composition according to the 
present invention. 
DETAILED DESCRIPTION OF THE INVENTION 
The liquid detergent composition according to the present invention 
comprises a mixture long chain amine oxides and a short chain surfactant. 
It has been found that the cleaning performance of the composition 
according to the present invention can be boosted by the incorporation of 
short chain surfactants. 
The compositions according to the present invention comprise at least one 
short chain surfactant, or mixtures thereof. All surfactants have in 
common that they comprise a hydrophobic portion and a hydrophilic portion. 
By short chain surfactant, it is meant herein surfactants which comprise a 
C.sub.6 -C.sub.10 alkyl chain as their hydrophobic portion. Such short 
chain surfactants are accordingly those conventionally used in this field, 
but with a shorter alkyl chain, and can be of any type. Accordingly, 
suitable short chain surfactants for use herein include C.sub.6 -C.sub.10 
alkyl sulphates (C.sub.6 -C.sub.10 SO.sub.4), alkyl ether sulphates 
(C.sub.6 -C.sub.10 (OCH.sub.2 CH.sub.2)eSO.sub.4), alkyl sulphonates 
(C.sub.6 -C.sub.10 SO.sub.3), alkyl succinates (C.sub.6 -C.sub.10 
OOCCH.sub.2 CH.sub.2 COOZ), alkyl carboxylates (C.sub.6 -C.sub.10 COOM), 
alkyl ether carboxylates (C.sub.6 -C.sub.10 (OCH.sub.2 CH.sub.2).sub.e 
COOM), alkyl sarcosinates (C.sub.6 -C.sub.10 CON(CH.sub.3)R), alkyl sulpho 
succinates (C.sub.6 -C.sub.10 OOCCH(SO.sub.3 M)CH.sub.2 COOZ), amine 
oxides (C.sub.6 -C.sub.10 RR'NO), glucose amides (C.sub.6 -C.sub.10 
CONR"X), alkyl pyrrolidones (C.sub.6 -C.sub.10 (C.sub.4 H.sub.6 ON), 
alkylpolysaccharides (C.sub.6 -C.sub.10 OG.sub.g), alkyl 
alkoxylates(C.sub.6 -C.sub.10 (OCH.sub.2 CH.sub.2)e(OCH.sub.2 CH.sub.2 
CH.sub.2).sub.p OH) and betaines (C.sub.6 -C.sub.10 N.sup.+ 
(CH.sub.3).sub.2 CH.sub.2 COO--). In the formulae in brackets, e and p are 
independently from 0 to 20 and e+p&gt;0, Z is M or R, M is H or any counter 
ion such as those known in the art, including Na, K, Li, NH.sub.4, amine, 
X is a polyhydroxyhydrocarbyl having a linear hydrocarbyl chain with at 
least 3 hydroxyls directly connected to the chain, or an alkoxylated 
derivative thereof, R, R' and R" are C.sub.1 -C.sub.5 alkyl groups, 
possibly functionalized with hydroxyl groups, R and R' are preferably 
C.sub.1 -C.sub.3, most preferably methyl, R" is preferably 2-hydroxyethyl 
or 2 hydroxypropyl, G is a saccharide, preferably glucose, and g is of 
from 1.5 to 8. All these surfactants are well known in the art. A more 
complete disclosure of conventional glucose amides can be found for 
instance in WO 92-06154 and a more complete disclosure of conventional 
alkyl polysaccharides can be found for instance in U.S. Pat. No. 
4,536,319. The compositions according to the present invention may 
comprise any of the above surfactants alone, or any combination thereof, 
depending on the end use envisioned. 
Preferred short chain nonionic surfactants for use herein are alkyl 
alkoxylates according to the formula C.sub.6 -C.sub.10 (OCH.sub.2 
CH.sub.2)e(OCH.sub.2 CH.sub.2 CH.sub.2).sub.p OH, where e and p 
representing respectively the degree of ethoxylation and propoxylation, 
are independently of from 0 to 20, and that e+p&gt;0. Most preferred short 
chain nonionic surfactants for use herein are those where e and p are such 
that e+p is from 3 to 10, particularly those where p is 0 and e is from 3 
to 8. Also, most preferred short chain nonionic surfactants for use herein 
are those where said short chain is a hydrocarbon chain comprising from 7 
to 10 carbon atoms. 
Said preferred short chain nonionic surfactants for use herein can be 
manufactured by the processes well known to the man skilled in the art, 
such as condensation of the corresponding alcohol and alkylene oxide, but 
such short chain surfactants are more conveniently commercially available 
for instance from Sidobre under the trade name Mergital@C4 (C8EO4), from 
Kolb under the trade names Imbentin@ AG/810/050 and AG/810/080 
(respectively C8-10EO5 and C8-10EO8). 
Preferred short chain anionic surfactants for use herein are C.sub.6 
-C.sub.10 alkyl sulphates (C.sub.6 -C.sub.10 SO4) and alkyl sulphonates 
(C.sub.6 -C.sub.10 SO.sub.3). Most preferred are the C6-C8 alkyl sulphates 
and sulphonates. Such short chain anionic surfactants can be made by well 
known sulphation or sulphonation processes followed by neutralization, but 
said anionic short chain surfactants are more conveniently commercially 
available, for instance from Rhone Poulenc under the trade name Rhodapon@ 
OLS, or from Witco under the trade name Witconate@. 
Preferred short chain surfactants for use herein are dimethyloctylamine 
oxide and octyl sulphate. Suitable short chain surfactants for use herein 
are preferably hypochlorite compatible. According to the present 
invention, the compositions comprise from 0.5% to 15%, preferably from 
0.5% to 10%, more preferably from 1% to 6%,and most preferably from 2% to 
4% by weight of the total composition of short chain surfactants. 
It has been observed that the incorporation of short chain surfactants in 
compositions comprising typical amine oxides described in the art results 
in the decrease of said compositions viscosity. It has now been found that 
the viscosity of the compositions is not disturbed by the use of specific 
mixtures of long chain amine oxides. 
According to the present invention suitable mixtures of long amine oxides 
for use herein are according to the formula R.sub.1 R.sub.2 R.sub.3 NO 
comprising a first amine oxide wherein R.sub.1 is a C.sub.14 alkyl group 
and a second amine oxide wherein R.sub.1 a C.sub.12 alkyl group or wherein 
R.sub.1 is a C.sub.16 alkyl group or mixtures thereof. R.sub.2 and R.sub.3 
are independently C.sub.1 to C.sub.3 alkyl groups in both said first and 
second amine oxides. 
The ratio of said first amine oxide to said second amine oxide wherein 
R.sub.1 is a C.sub.12 alkyl group is from 0.3 to 10, preferably from 0.5 
to 5 and wherein the ratio of said first amine oxide to said second amine 
oxide wherein in said second amine oxide R.sub.1 is a C.sub.16 alkyl group 
is from 0.2 to 4.5, preferably from 0.5 to 2. 
Preferred long chain amine oxides for use herein can be Genaminox.RTM. LA, 
Gemaminox.RTM. MY-X (available from Hoechst), C.sub.12 -C.sub.14 
Aromox.RTM. DMMCO-W, (AKZO), Aromox DM14D-W, (AKZO) and Aromox DM14D-W 
(AKZO). Suitable long chain surfactants for use herein are preferably 
hypochlorite compatible. According to the present invention, said 
compositions comprise from 1.5% to 10%, preferably from 1.5% to 7% more 
preferably from 2% to 5% and most preferably from 2.5% to 4% by weight of 
the total composition of said mixture of long chain amine oxides of the 
present invention. Compositions according to the present invention 
comprise said mixture of long chain amine oxides so that compositions 
independently comprise from 0.4% to 6% by weight of the total composition 
of said first amine oxide, preferably from 0.5% to 4% and from 0.5% to 4% 
by weight of said second amine oxide, preferably from 0.5% to 3%. 
The compositions according to the present invention comprise said mixture 
of long chain amine oxides and said short chain surfactants in a ratio of 
from 0.25 to 3, preferably 0.5 to 2. 
The long chain amine oxide of the present invention restore the viscosity 
to a value of from 50 cps to 2000 cps, preferably from 100 cps to 700 cps, 
measured with a Brookfield viscosimeter RVT at a temperature of 25.degree. 
C. using spindle numbers 2 or 3 or 4 at 50 r.p.m. or 100 r.p.m. 
The compositions according to the present invention may further comprise as 
an optional ingredient other long chain surface active agents. Suitable 
long chain surface actives include alkyl sarcosinates, paraffin 
sulphonates, alkyl sulphates and alkyl ether sulphates. 
A preferred optional ingredient is C.sub.12 alkyl sulphate, the weight 
ratio of short chain surfactant to C.sub.12 alkyl sulphonate being of 1:4 
to 4:1. 
Another optional component of the present invention is an alkali metal salt 
of a C.sub.8 -C.sub.18 fatty acid. Suitable fatty acids for use herein can 
be any C.sub.8 -C.sub.18 fatty acid, preferably fully saturated, 
preferably a sodium, potassium or lithium salt, more preferably the sodium 
salt. Suitable fatty acids may be selected from caprylic acid, capric 
acid, lauric acid, myristic acid, palmitic acid, stearic acid and mixtures 
of fatty acids suitably hardened, derived from natural sources such as 
tallow, coconut oil, ground oil and babassu oil. 
Compositions according to the present invention comprise from 0.2% to 2%, 
preferably from 0.5% to 1% by weight of the total composition of fatty 
acids. Said fatty acids may be used as an additional thickening aid and as 
suds suppressers. 
Another optional ingredient according to the present invention is a 
hypochlorite bleaching agent, preferably an alkali metal hypochlorite. 
Although alkali metal hypochlorites are preferred other hypochlorite 
compounds may also be used herein and can be selected from calcium and 
magnesium hypochlorite. Preferred alkali metal hypochlorite for use herein 
is sodium hypochlorite. Compositions according to the present invention 
comprise said hypochlorite bleaching agents such that the content of 
active chlorine in the compositions is from 0.4% to 4%, preferably from 1% 
to 2%. According to the present invention the ingredients of the 
compositions are selected so that the compositions are hypoclorite 
compatible. 
An optional requirement of the compositions according to the present 
invention that the pH is greater than 12, preferably greater than 12.5, 
more preferably greater than 12.8. This is achieved by the addition of a 
caustic alkali. Suitable caustic alkalis for use herein include sodium and 
potassium hydroxide. 
The compositions according to the present invention may also comprise a 
number of additional ingredients such as colourants and perfumes. 
Additionally, the compositions according to the present invention may 
comprise silicates used as corrosion inhibitors. 
The compositions according to the present invention are prepared by methods 
well known in the art such as the methods described in GB 1 329 086. The 
compositions according to the present invention can be prepared by mixing 
all of the ingredients in a non-metallic apparatus at room temperature. 
Preferably, the surfactant blend is first prepared by adding the short 
chain surfactant to the long chain component. Perfume and the alkali metal 
hypochlorite are then added whilst stirring. Colourants are added after 
all the other ingredients have been mixed. 
The compositions of the present invention may be used for a variety of 
cleaning purposes such as cleaning hard surfaces whereby said compositions 
thickened nature result in longer adhesion to the surface than 
non-thickened compositions. Said compositions are particularly suitable in 
the cleaning of inclined surfaces including toilet bowls. 
In another embodiment of the present invention the compositions herein are 
used in dishwashing applications, including hand dishwashing as well as 
washing with automatic dishwashing machines. We have found that said 
compositions give particularly good cleaning performance, especially in 
terms of soil removal when used as a pretreatment composition for treating 
dishes especially pans, pots kitchen grills and/or any kitchenware soiled 
by though food stains/encrustations. 
Accordingly the present invention encompasses a process of treating dishes 
which comprises the steps of contacting said dishes with a composition 
according to the present invention in its diluted or neat form, then 
allowing said dishes to remain in contact with said composition for a 
period of time sufficient to treat said dishes, preferably from 2 to 15 
minutes, then rinsing said dishes in water to remove said composition. 
Said process mentioned herein may be followed by a subsequent step where 
said dishes are washed with a dishwashing product including the one of the 
present invention or any other coventional diswashing product. Indeed said 
subsequent step may be either a hand dishwashing operation or a 
dishwashing performed in automatic dishwashing machines. 
Alternatively said process of treating dishes mentioned herein before can 
be preceded by a step where said dishes are soaked in water before being 
contacted with a composition of the present invention. 
By "in its diluted form" it is meant herein that the compositions according 
to the present invention may be diluted with water. Typically dilution 
levels are of from 0.5% to 3% by weight of a composition of the present 
invention in water. Said dilution may occur before or while a composition 
of the present invention is applied to said dishes. 
As used in the foregoing paragraphs, the expression "treating" includes 
washing as the compositions according to the present invention comprise 
surfactants and bleaching as the preferred compositions of the present 
invention comprise hypochlorite.