EP1023423B1

EP1023423B1 - Alkoxylated amines and their use in cleaning compositions

Info

Publication number: EP1023423B1
Application number: EP98955491A
Authority: EP
Inventors: Marcella M. L. nilever Italia S.p.a. BARTOLETTI; Giuseppe Vincenzo Unilever Italia S.p.A. BOLZONI; Emanuela Unilever Italia S.p.A. FERRO; Marco Unilever Italia S.p.A. GALLI; Ronald Meredith Morris
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 1997-10-13
Filing date: 1998-10-09
Publication date: 2004-02-11
Anticipated expiration: 2018-10-09
Also published as: JP2001520259A; CA2305193C; HUP0004913A2; AU1229899A; IN185797B; HU224521B1; KR20010015748A; BR9813044A; WO1999019431A1; DE69821636T2; GB9721691D0; SK5302000A3; MY123176A; TR200000972T2; AU735924B2; HUP0004913A3; EP1023423A1; PL188434B1; JP4323093B2; AR017315A1

Description

Technical Field

The present invention relates to acidic cleaning compositions, and in particular to acidic antimicrobial cleaning composition suitable for use on hard surfaces.

Background to the Invention

Many formulations have been proposed in the literature for so-called 'descaler' compositions. These generally comprise sufficient acid to give a low pH and may comprise a thickening agent to as to cause the composition to be retained on sloping surfaces, such as the inside of toilet bowls. As described in more detail below, known thickeners include both ethoxylated and unethoxylated tertiary amines, either alone or in combination with a hydrotrope. Known acids for use in such compositions include sulphamic and phosphoric acids.
GB 1443244 relates to acid cleaners and descalers which comprise as a thickening agent an ethoxylated tertiary amine of which ETHOMEEN S12 (N,N-dihydroxyethyl-oleylamine) is given as an example. The composition also comprises acids which are selected from mineral acids and acid salts of strong inorganic acids such as sulphamic acid. Bacteriocides are an additional, optional component.
FR 2459830 discloses compositions which comprise non-ethoxylated and ethoxylated amines together with sulphamic acid. The composition may also comprise disinfectants.
AU-A-57022/86 relates to cleaning systems which comprise a mixture of sulphamic and phosphoric acids and an acid stable surfactant. Bacteriocides are optional and formalin is disclosed as a bacteriocide which improves the antibacterial effect of the acids.
EP-B-0276501 discloses thickened aqueous cleaning compositions which comprise 0.1-50%wt of a weak acid having a pK >2 (of which sulphamic acid is given as an example), 0.1-20%wt of an amine which can include 2% of oleyl-bis(2-hydroxyethyl)amine and 0.01%-5%wt hydrotrope (sodium xylene-sulphonate is given as an example). Disinfecting agents are optional.
EP-A-0314232 relates to compositions which undergo a viscosity increase on dilution and discloses that thickened liquid detergent compositions can be prepared with an amine oxide, amine (such as ETHOMEEN S12), betaine or quaternary ammonium compound and hydrotrope (sodium xylene-sulphonate). It is stated in the specification that amine oxides and quaternary ammonium compounds are known to have biocidal properties and that further microbiocides including organic peracids are optional. These compositions can be of acidic, neutral or alkaline pH.
One problem with the known compositions is that the viscosity of the compositions drifts with time, and, in particular falls when the product is stored.

Brief Description of the Invention

We have determined that compositions which comprise a specific mixture of both saturated and unsaturated alkoxylated aliphatic amines in the presence of an anionic surfactant show an improved stability of viscosity on storage. Surprisingly, we have found that the addition of a anionic sulphonate surfactant hydrotrope to these formulations has the additional benefit that the surface energy of surfaces treated with the composition is reduced and the subsequent deposition of limescale is retarded.

Detailed Description of the Invention

According to a first aspect of the present invention there is provided a cleaning composition which comprises
a) 0.01-15%wt of an alkoxylated aliphatic amine with 8-18 carbon atoms and 1-8 moles ethoxylation wherein the mole ratio of saturated to unsaturated aliphatic residues falls in the range 40:60 to 80:20, and
b) 0.01-15%wt of an anionic surfactant hydrotrope in an amount such that the mole ratio of the ethoxylated amine to the anionic surfactant hydrotrope is in the range of 3 to 3.5.
According to a second aspect of the present invention there is provided a process for retarding the deposition of limescale on a surface which comprises the step of treating said surface with a cleaning composition as defined above, said composition having a pH of less than 1.

Amines

Typically, the alkoxylated aliphatic amine is an ethoxylated tertiary amine of the general formula: H(A)_x-N(R)-(A)_yH wherein R is an alkyl or alkenyl group comprising 8-18 carbon atoms, A is an ethoxy or propoxy group and x and y may be the same or different and are integers from 1-3.
The preferred materials are ethoxylated amines wherein A is -OCH₂CH₂-.
Preferably x and y are both 1. In preferred embodiments of the invention R is mixed saturated and unsaturated C14-C18 alkyl and is most preferably derived from fatty acids residues of which the majority correspond to oleic and/or stearic acids.
Preferably the mole ratio of saturated to unsaturated fatty acids falls into the range 50:50 to 66:33.
A particularly suitable alkoxylated aliphatic amine is a material known as ETHOMEEN BTB/12™, available from AKZO. BTB/12 is believed to be a mixture of material derived from fully hardened tallow and the oleyl derivative in a 65/35 ratio. Such a mixed material can be prepared by synethesis using an appropriate ratio of mixed starting materials or obtained by mixing an alkoxylated aliphatic amine such as ETHOMEEN HT12™ (ex AKZO) with an unsaturated material such as ETHOMEEN S12. ETHOMEEN S12™ (ex AKZO) is N,N-(dihydroxyethyl)-oleylamine.
In embodiments of the invention as cleaning products, the preferred levels of the alkoxylated aliphatic amine are 1-10%wt on product with levels of 2-6%wt on product being particularly preferred.

Anionic Surfactants

In particularly preferred embodiments of the invention the alkoxylated aliphatic amine is present together with an anionic surfactant hydrotrope. Preferably, the levels of these materials are such that they interact so as to thicken the composition.
Suitable anionic surfactant hydrotropes include the sulphonate hydrotropes. Preferred surfactant hydrotropes are alkylarylsulphonates such as salts, particularly alkali metal salts, of toluene, cumene or xylene sulphonate. The preferred anionic surfactant is sodium cumenesulphonate. A suitable material is ELTESOL SC 40™ (ex. Albright and Wilson). Typical levels of anionic surfactant range from 0.05-2%wt on product.
Preferably, formulations comprising the alkylaryl sulphonates are formulated at a pH below 1. Without wishing to limit the invention by reference to any theory of operation, it is believed that at a pH below 1, the ethoxylated amine behaves as a cationic surfactant and interacts with the alkylaryl sulphonate to form a water-insoluble gel which deposits as a monolayer on surfaces. It is believed that this monolayer lowers the surface energy of the surface and retards or prevents the deposition of further limescale.
The preferred mole ratio of the ethoxylated amine and the anionic surfactant is 3.25-3.5.
The preferred viscosity of the cleaning compositions according to the present invention is between 50 mPas and 1000 mPas when measured at 11.7 sec^-1 shear and at 25°C using Haake RV2 rotoviscometer (RTM) and an MV1 bob

Acids

Typically, cleaning compositions which embody the present invention comprise 0.01-15%wt of a limescale removing acid, preferably an organic acid and more preferably sulphamic acid. In such embodiments, typical levels of the acid (for instance the amino sulphonic acid) range from 1-10%wt on product with levels of 2-6% on product being particularly preferred.
It is preferred that the pH of the compositions according to the invention should have a pH of <2.0, more preferably a pH <1.0.

Peroxygen Sources

Preferred embodiments of the invention are cleaning and/or hygiene compositions which comprises a peroxygen compound.
Where present, typical sources of peroxygen species include one or more of hydrogen peroxide, peracetic acid and/or other organic or inorganic peroxygen sources. Hydrogen peroxide is a preferred source of peroxygen species.
Typical levels of hydrogen peroxide range from 1-10%wt on product with levels of 3-8% being particularly preferred.

Nonionic Surfactants

Preferred compositions according to the invention additionally comprise nonionic surfactant.
Suitable nonionic surfactants include alkoxylated alcohols, preferably ethoxylated alcohols. Suitable nonionic detergent active compounds can be broadly described as compounds produced by the condensation 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 hydrophilic or polyoxyalkylene radical which is condensed with any particular hydrophobic group can be readily adjusted to yield a water-soluble compound having the desired degree of balance between hydrophilic and hydrophobic elements.
The preferred alkoxylated alcohols are selected from the group comprising ethoxylated alcohols of the general formula: R₁-(OCH₂CH₂) _m-OH wherein R₁ is straight or branched, C₈ to C₁₈ alkyl or hydroxyalkyl and m is, on average, 1-14. Ethoxylated alcohols suitable for use in the present invention include LIAL 111.10EO [TM] available in the marketplace from DAC. Typical levels of nonionic surfactant in products according to the present invention range from 0-5%.
Particularly preferred compositions according to the present invention comprise:
a) 1-10%wt, preferably 3-5%wt sulphamic acid,
b) 1-10%wt, preferably 2-5%wt ethoxylated amine,
c) 0-5%wt, preferably 0.05-1%wt, nonionic surfactant,
d) 0.05-2%wt, preferably 0.4-1.1%wt, anionic surfactant hydrotrope,
e) 1-10%wt, preferably 4-6%wt, hydrogen peroxide

Minors

While the combination of the surfactants in the compositions of the invention provide a thickening effect it is possible to add other thickeners. Gums, particularly xanthan gums are suitable thickeners. Preferred xanthan gums are the Kelzan™ series (available from Kelco Corp). Typical levels of xanthan gum range from 0.05-1wt%. The resulting viscosity of the composition, as measured on a Haake RV2 rotoviscometer) is preferably in the range 10-200 mPas at 20 sec^-1 shear and 25°C, using an MV1 bob. More preferably the viscosity is 10-100 mPas under the conditions mentioned above.
Metal ion sequestrants such as ethylene diamine tetraacetates, amino-poly phosphonates (such as those in the DEQUEST™ range ex. Monsanto) and phosphates and a wide variety of other poly-functional organic acids and salts, can also optionally be employed. Preferred metal ion complexing agents are selected from dipicolinic acid, ethylene diamine tetra acetic acid (EDTA) and its salts, hydroxy-ethylidene diphosphonic acid (Dequest 2010), ethylenediamine-tetra(methylene phosphonic acid) (Dequest 2040), diethylene-triamine-penta(methylene phosphonic acid) (Dequest 2060).
Optional, minor components also include those typically found in cleaning compositions and are selected from opacifiers, colours perfumes and fluorescers.
Preferred levels of perfume range from 0.05-2%wt. Acid stable perfumes are available from a variety of sources.

A particularly preferred composition according to the present invention comprises:

ETHOMEEN BTB/12	ex AKZO	2-5%	Ethoxylated amine
SULPHAMIC ACID
		4%
HYDROGEN PEROXIDE
		5%
LIAL 111.10EO	ex DAC	0.1%	Nonionic surfactant
ELTESOL SC40	ex Albright	0.4-1.1%	Sodium Cumene Sulphonate
BRILLIANT BLUE 9	ex WJE	0.0021%	CI 307047/colour
PERFUME	ex IFF	0.12%	Othello 39
DEQUEST 2066	ex Monsanto	0-0.3%
WATER		to 100%

Typical products having the above formulation made with 3.0%wt of the amine and around 0.56%wt of the SCS are preferably clear, have a specific gravity of 1.040 g/ml, an initial viscosity at 106 sec^-1 (at 25°C) of 120mPas, an initial viscosity at 11.7 sec^-1 (at 25°C) of 300-600 mPas and pH 0.9 (at 25°C).
In order that the present invention may be further understood it will be illustrated hereafter with reference to the following non-limiting examples and with reference to the accompanying figures wherein:
Figure 1 shows the viscosity of materials according to the present invention and comparative examples in mPas at 11.7 sec^-1 as measured using on a Haake RV2 rotoviscometer and an MV1 bob after storage at room temperature.
Figure 2 shows the viscosity of materials according to the present invention and comparative examples in mPas at 106 s-1, as measured using on a Haake RV2 rotoviscometer (RTM) and an MV1 bob after storage at room temperature.
Figure 3 shows the viscosity of materials according to the present invention and comparative examples in mPas at 106 s-1, as measured using on a Haake RV2 rotoviscometer and an MV1 bob after storage at 37°C.
Figure 4 shows the viscosity of materials according to the present invention and comparative examples in mPas at 11.7 sec^-1 measured on a Haake RV2 rotoviscometer and an MV1 bob after storage at 37°C.

EXAMPLES:

Example 1: Viscosity Stability

A composition was prepared as follows:

ETHOMEEN BTB/12	ex AKZO	3%	Ethoxylated amine
SULPHAMIC ACID
		4%
HYDROGEN PEROXIDE
		5%
LIAL 111.10EO	ex DAC	0.1%	Nonionic surfactant
ELTESOL SC 40	ex Albright	0.4-1.1%*	Sodium Cumene Sulphonate
BRILLIANT BLUE	ex WJE	0.0021%	CI 307047/colour
PERFUME	ex IFF	0.12%	Othello 39
DEQUEST 2066	ex Monsanto	0.15%
WATER		to 100%

In order to demonstrate the interaction of the ethoxylated amine and the anionic surfactant, the other components were each under and over dosed at +/- 10%. Results are shown in Table 1 below, for an initial viscosity of 500 m.Pas at 11.7 sec^-1 shear.

VISCOSITY
Component	-10%	+10%
ETHOMEEN BTB/12	950	190
SULPHAMIC ACID	530	600
HYDROGEN PEROXIDE	550	620
LIAL 111.10EO	560	460
ELTESOL SC 40	145	1330
PERFUME	510	600
DEQUEST 2066	470	560

From the above it can be seen that the greatest modification of viscosity occurs when the relative levels of the anionic surfactant and the ethoxylated amine are varied, and that variation in the levels of the other components has little effect.

As shown by the figures in Table 2 below, the molar ratio of the ethoxylated amine / anionic surfactant can be modified to give thickening at a range of viscosities. Again, a finished product similar to that described above was used.

(all with 3.0% Ethomeen BTB12)
% Sodium Cumene	Molar Ratio	Viscosity mMas (11.7 sec^-1 shear, 25°C)
0.69%	2.89	1500(non-flowing gel)
0.63%	3.03	1000
0.60%	3.18	700
0.59%	3.24	400
0.57%	3.35	300
0.56%	3.42	200
0.54%	3.51	75
0.50%	3.83	-10(water thin)

Compositions having a viscosity between 50 mPas and 1000 mPas (a molar ratio of from 3-3.5) were flowable compositions which were suitable for use as toilet cleaners. Compositions with a lower viscosity were too thin to stay on sloping surfaces, while those with a higher viscosity could not be dispensed with ease. Compositions with a viscosity of from 200-700 mPas were particularly suited to this purpose.
A range of compositions of the type described above were prepared with differing degrees of saturation in the ethoxylated amine. The materials used were:

'S12': an N,N-dihydroxyethyl-oleylamine (ETHOMEEN S12),
'HT12': a fully hardened N,N-dihydroxyethyl-tallowylamine (ETHOMEEN HT12),
'50/50': an equal weight mixture of 'S12' and 'HT12', and
'66/33': a mixture of 'HT12' and 'S12' in a 66:33 weight ratio (similar to BTB12)

The effect of storage on viscosity is shown in figures 1-4.
Figure 1 shows the viscosity of materials according to the present invention and comparative examples in mPas at 11.7 sec^-1, as measured using on a Haake RV2 rotoviscometer and an MV1 bob after storage at room temperature. It can be seen that the viscosity of the 'HT12' sample rose with time until the product became a non-flowing gel. The viscosity of the 'S12' sample fell, such that the product eventually became too thin to be retained on sloping surfaces. The viscosities of the products containing a mixture of hardened and unhardened tallow remained in the acceptable range on storage.
Figure 2 shows the viscosity of materials according to the present invention and comparative examples in mPas at 106 sec^-1, as measured using on a Haake RV2 rotoviscometer and an MV1 bob after storage at room temperature. It can be seen that the viscosity of the 'HT12' sample first fell and then rose. The viscosity of the 'S12' sample fell, such that the product eventually became too thin to be retained on sloping surfaces. The viscosities of the products containing a mixture of hardened and unhardened materials remained in the acceptable range on storage.
Figure 3 shows the viscosity of materials according to the present invention and comparative examples in mPas at 106 sec^-1, as measured using on a Haake RV2 rotoviscometer and an MV1 bob after storage at 37°C. It can be seen that the viscosity of the 'HT12' sample again first fell and then rose. The viscosity of the 'S12' sample fell, such that the product eventually became too thin to be retained on sloping surfaces. The viscosities of the products containing a mixture of hardened and unhardened materials remained in the acceptable range on storage.
Figure 4 shows the viscosity of materials according to the present invention and comparative examples in mPas at 11.7 sec^-1, as measured using on a Haake RV2 rotoviscometer and an MV1 bob after storage at 37°C. It can be seen that the viscosity of the 'HT12' sample again rose. The viscosity of the 'S12' sample fell, such that the product eventually became too thin to be retained on sloping surfaces. The viscosities of the products containing a mixture of hardened and unhardened materials remained in the acceptable range on storage.

Example 2: Limescale Prevention

Hard water of -60 degrees French was prepared by flushing carbon dioxide through tap-water containing both calcite and dolomite overnight. Pairs of tiles were cleaned with a detergent composition and ethanol and rinsed with tap water. One of the tile was treated with a composition according to the present invention (that of Example 1), with a contact time of 20 minutes: the tile was then rinsed with water. The hard water was then dripped onto the tiles for 24 hours, allowing one drop to fall onto each tile every five minutes. Results for treated and untreated tiles were compared visually using a panel of ten people, scoring on a scale of 0=limescale absent and 5= more encrusted tile: results being presented in Table 3 below. In addition the limescale was titrated after dissolution with dilute HCl. The results of titration are expressed in mg of calcium carbonate per tile in Table 3 below.
Examples were performed in replicates A, B and C.

Treated Tile Untreated Tile

Replicate Visual mg CaCo₃ visual mg CaCo₃

A 3.3 0.91 5.0 2.1

B 3.4 1.2 5.0 1.5

C 3.3 1.4 5.0 2.1
It can be seen from these results that the treatment of the tile had a measurable effect on the degree of limescale deposited on the tile in the test both as measured chemically and as seen on the surface.

Claims

A cleaning composition comprising an alkoxylated aliphatic amine and an anionic surfactant hydrotrope characterised in that it comprises:

a) 0.01-15%wt of an alkoxylated aliphatic amine with 8-18 carbon atoms and 1-8 moles ethoxylation wherein the mole ratio of saturated to unsaturated aliphatic residues falls in the range 40:60 to 80:20.

b) 0.01-15% wt of an anionic surfactant hydrotrope in an amount such that the mole ratio of the ethoxylated amine to the anionic surfactant hydrotrope is in the range of 3 to 3.5.
A composition according to claim 1 wherein the ethoxylated aliphatic amine is according to the general formula: H(A)_x-N(R)-(A)_yH wherein R is an alkyl or alkenyl group comprising 8-18 carbon atoms, A is an ethoxy group and x and y may be the same or different and are integers from 1-3.
A composition according to claim 2 wherein x and y are both 1.
A composition according to claim 1 wherein R is mixed saturated and unsaturated C14-C18 alkyl.
A composition according to claim 1 wherein the mole ratio of saturated to unsaturated fatty acids in the alkoxylated aliphatic amine falls into the range 50:50 to 66:33.
A composition according to claim 1 wherein the pH of the composition is less than 1.0.
A composition according to claim 1 wherein the mole ratio of the ethoxylated amine and the anionic surfactant is 3.25-3.5.
A composition according to claim 1 wherein the anionic surfactant is an alkylaryl sulphonate hydrotrope
A composition according to claim 1 having a viscosity between 50 mPas and 1000 mPas when measured at 11.7 sec^-1 shear and at 25°C using Haake RV2 rotoviscometer and an MV1 bob.
A composition according to claim 1 comprising 0.01-15%wt of a limescale removing acid.
A composition according to claim 1 which further comprises a peroxygen compound.
A composition according to claim 1 which comprises:

a) 1-10%wt, preferably 3-5%wt sulphamic acid,

b) 1-10%wt, preferably 2-5%wt ethoxylated amine,

c) 0-5%wt, preferably 0.05-1%wt, nonionic surfactant,

d) 0.05-2% wt, preferably 0.4-1.1% wt, anionic surfactant hydrotrope, and,

e) 1-10%wt, preferably 4-6%wt, hydrogen peroxide
A process for retarding the deposition of limescale on a surface which comprises the step of treating said surface with a cleaning composition according to any of claims 1-12 said composition having a pH of less than 1.