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(11) | EP 0 639 833 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | The use of magnesium ions in hard surface cleaners for improved shine, and cleaners obtained accordingly |
(57) The use of magnesium ions is disclosed in hard surface cleaning compositions comprising
an anionic surfactant system, whereby the residuality of said compositions on said
surfaces is reduced.
Technical Field
Background
[0002] Compositions for the cleaning of hard surfaces are extensively discussed in the art. It is desirable that such compositions should have, in particular, the ability to provide a good shine to the cleaned surfaces. However, surface shine is often compromised by residues of the compositions which are left on said surfaces and which appear as streaks as water evaporation is completed.
[0003] This streaking phenomenon caused by a composition's residuality tends to be more of a problem as said composition is formulated as a concentrate, i.e it comprises more actives and less water.
[0004] Also, for a given composition, the residuality of said composition is even more noticeable as said composition is used to clean surfaces made of glossy materials, such as glossy ceramic tiles, windows and mirrors, or such materials as polyurethane-coated PVC which is widely used in Northern America.
[0005] Also, many products of today are formulated or can be used as no-rinse products. This residuality problem tends to be more acute for such products or in such conditions, as the rinsing step performed for other products cannot participate here to decreasing the residuality.
[0006] It is thus an object of the present invention to provide improved shine to hard surfaces, in a manner which is applicable to a variety of cleaning compositions, and a variety of surfaces.
[0007] Various solutions have been proposed in the art to meet this object, including the use of certain solvents, or the formulation of specific ingredient combinations.
[0008] It has now been found that this object could be met by formulating a composition which comprises an anionic surfactant system and an effective amount of magnesium ions as counterions for said anionic surfactants. In other words, for any given cleaning composition comprising an anionic surfactant system, which causes residues to appear on cleaned surfaces, adding an appropriate amount of magnesium ions will cause said residues to appear less, or even not to appear anymore.
[0009] Cleaning compositions comprising magnesium ions have been extensively described in the art, mainly in the context of dish washing, for instance in WO-A-9 206 171, WO-A-9 206 156, US-A-4 129 515, GB-A-2 078 246, EP-A-0 107 946, EP-A-0 062 371, FR-A-2 324 723 and FR-A-2 296 688, but the benefits derivable therefrom in terms of low residuality have never been acknowledged.
Summary of the Invention
[0010] The present invention encompasses the use, in a composition for the cleaning of hard surfaces, said composition comprising an anionic surfactant system, of magnesium ions as counterions for said anionic surfactant system, whereby the residuality of said cleaning composition on said surfaces is reduced.
[0011] The present invention further encompasses a concentrated cleaning composition which comprises short chain surfactants and magnesium ions.
Detailed Description of the Invention
[0012] In it broadest embodiment, the present invention encompasses the use of magnesium ions, as counterions for anionic surfactants, to reduce the residuality of cleaning compositions for hard surfaces.
[0013] As used herein, the word "residuality" refers to the propensity of a composition to leave visible residues on a given surface. A composition with a high residuality is a composition which leaves substantially visible residues on surfaces, and which is therefore improper for use in a no-rinse mode. A composition's residuality in given usage conditions can be evaluated by measuring the glossiness of a surface cleaned with said composition, for instance using a glossmeter as described hereinafter.
[0014] The present invention is based on the finding that, in compositions comprising an anionic surfactant system, using magnesium ions as counterions for said anionic surfactant system will reduce the residuality of said compositions. This residuality reduction phenomenon, i.e. the reduction of the visibility of residues, but not necessarily the amount of residues, is clearly noticeable by eye, and it can be quantified by measuring the glossiness of a given surface cleaned with a given composition without magnesium ions, compared to the same reading with the same composition supplemented with magnesium ions.
[0015] The results obtained are independent of whether the magnesium ions are introduced in the composition with the anionic surfactant system, or as a separate ingredient, i.e, it is unimportant whether the anionic surfactant system is neutralized by the magnesium ions in situ or not. If not, the magnesium ions can be introduced in the compositions in any given form. Suitable forms of magnesium for use herein include Magnesium sulphate, nitrate, and halogens.
[0016] The residuality reduction is dependant on the amount of magnesium ions added. Thus, more or less magnesium ions can be added depending on the degree of residuality desired. In a preferred embodiment, an amount of magnesium ions is used which is sufficient to act as counterion for the totality of anionic surfactant present. Adding more magnesium ions beyond that provides no extra benefit and is thus unattractive from an economical viewpoint. Accordingly, it is preferred that the molar ratio of said bound magnesium ions to said anionic surfactant be of 1:2. Depending on specifics, mainly the type of anionic surfactant used, the counterion for said anionic surfactant raw material, when said counterion is not magnesium, and the binding constants for these, it may be appropriate to add more magnesium in order to arrive at said ratio of 1:2. The appropriate amount of magnesium for a given composition and to obtain a desired result can also be achieved by simple trial and error.
[0017] The compositions suitable for use in the present invention comprise an anionic surfactant system. By anionic surfactant system, it is meant herein that the compositions comprise at least one anionic surfactant.
[0018] Suitable anionic surfactants for use herein include those well known in the art, i.e. C6-24 alkyl sulfates, alkyl ether sulfates, alkyl sulfonates, alkyl benzene sulphonates, alkyl succinates, alkyl carboxylates, alkyl ether carboxylates, alkyl sarcosinates, alkyl sulfo succinates and the like. Particularly preferred for use herein are alkyl sulfonates, alkyl sulfates, alkyl benzene sulphonates and alkyl ether sulfates.
[0019] While anionic surfactants derived from longer alkyl chains, i.e. C11 and up are traditionally used to formulate hard surface cleaning compositions, it has been found advantageous to use anionic surfactants derived from shorter alkyl chains, i.e. C6 to C10 to formulate concentrated aqueous cleaning compositions which comprise less water than the traditional cleaning compositions. Indeed, it has been found that short chain surfactants allow to formulate stable and clear concentrated cleaning compositions, whereas the same compositions with only longer chain homologues are unclear or unstable. Short chain anionic surfactants are commercially available for instance from Rhone Poulenc under the trade name Rhodapon@, or from Witco under the trade name Witconate@. As used herein , "concentrated cleaning compositions" refers to compositions which comprise from 10% to 80% by weight of the total composition of water, preferably from 15% to 75%, most preferably from 30% to 75%.
[0020] Thus to summarize, the compositions herein comprise as an essential feature an anionic surfactant system, which represents from 0.5% to 50% by weight of the total composition, preferably from 1% to 20%. Said anionic surfactant system may consist of long chain anionic surfactants only, or mixtures thereof; it may also comprise mixtures of short chain and long chain anionic surfactants. Preferred for use herein is a mixture of short chain and long chain anionic surfactants.
[0021] In addition to said anionic surfactant system, the compositions herein may comprise a wide variety of co-surfactants of other types, e.g. nonionic and zwitterionic surfactants, preferably nonionic surfactants.
[0022] As for anionic surfactants herein above, it has been found that short chain nonionic surfactants of the alkyl alkoxylate type (C₆-₁₀ (OCH₂CH₂)e (OCH₂CH₂CH₂)p OH, wherein e and p are independently from 0 to 20 and e+p>0) also provide benefits in formulating concentrated cleaning compositions. Alkyl alkoxylates are well known in the art, and the short chain alkyl alkoxylates suitable for use herein are also available on the market, for instance from sidobre under the trade name Mergital@C4 (C8EO4), from Kolb under the trade names Imbentin@ AG/810/050 (C8-10EO5) and AG/810/080 (C8-10EO8).
[0023] It has also been found that certain short chain nonionic surfactants have particular benefits as follows. C6-8 alkyl alkoxylates, as defined hereinabove, provide superior neat grease cleaning, and they are particularly mild to the skin. C6-10 alkyl alkoxylates as defined hereinabove are low foaming surfactants. C8-10 alkyl alkoxylates as defined hereinabove are particularly effective for dilute grease cleaning and for soap scum removal.
[0024] Thus the compositions herein may further comprise from 0.5% to 80% by weight of the total composition, preferably from 1% to 50%, of co-surfactants which are preferably nonionic surfactants, and which may be only long chain nonionic surfactants or mixtures thereof, only short chain surfactants or mixtures thereof, or mixtures of short and long chain nonionic surfactants. Preferred for use herein is a mixture of short chain and long chain nonionic surfactants.
[0025] The compositions herein can be formulated in a variety of pH range, depending on the end-use envisioned. However, it is preferable not to formulate at a pH above 10, as magnesium may then form magnesium hydroxide which does not participate to residuality reduction. Also, it is preferable not to formulate at a pH below the anionic surfactant's pK, as said anionic surfactant then becomes protonated, and cannot effectively bind magnesium anymore.
[0026] The compositions herein may further comprise a variety of other ingredients, including, solvents, bleaches, enzymes, dyes, perfumes and other aesthetics.
Examples-Experiments
[0028] The following compositions were evaluated in terms of their residuality with a Sheen 155 Gloss meter. The following data was generated with the following compositions at 0.3-1.5% dilution levels in 5 US grains/gallon water hardness on different types of tiles. As implement a sponge was used. Results are expressed in terms of D gloss (= gloss before - gloss after application of the product). So the smaller the difference, the less residuality.
| 1 | 2 | |
| NaPS | 3 | 3 |
| MgCl₂. 6H₂O | - | 1 |
| C13-15 (EO)30 | 2 | 2 |
| C13-15 (EO)7 | 1 | 1 |
| palm kernel fatty acid | 0.4 | 0.4 |
| water/minors | balance | balance |
| D gloss (white ceramic tiles) | 6.9 | 0.4 |
[0029] Compositions 1 and 2 were used dilute at 1.2% dilution level. Tests were done on white non-glossy ceramic floor surfaces. Composition 1 (without magnesium ions) gave very visible spots and streaks. The D gloss value on white ceramic tiles was 6.9. Composition 2 (with magnesium ions) showed no visible residues on the white ceramic tiles. This was translated in the D gloss value, which was only 0.4.
| 3 | 4 | 5 | |
| NaPS | - | - | 5 |
| MgSO4. 7 H₂O | - | - | 2 |
| C13-15 (EO)30 | 5 | 5 | 5 |
| C12-13 (EO)3 | - | 3 | 3 |
| C8-10 (EO)5 | 10 | 10 | 10 |
| C8 alkyl sulphate | 7 | 7 | 7 |
| 2-hexyl decanol | 1 | 1 | 1 |
| palm kernel fatty acid | 0.5 | 0.5 | 0.5 |
| water/minors | balance | balance | balance |
| D gloss (black glossy ceramic tiles) | 8.6 | 3.2 | 2.0 |
[0030] Compositions 3-5 were used at 0.6% dilution. Tests were done on different types of typical floor surfaces. Following results were noticed:
[0031] Composition 3 (without magnesium ions) gave streaks on most hard surfaces. For example, on light colored non-glossy ceramic tiles, which are representative of a typical European floor, composition 3 gave visible streaks. On a black glossy tile the residue formation was even more visible. The residue was measured via gloss readings on the black glossy ceramic tiles. The D gloss value was 8.6.
[0032] Composition 4 (same as 3, but with a further nonionic surfactant) showed no visible streaks on the light colored non-glossy surfaces, due to the improved spreading wetting properties of the relatively hydrophobic C12-13 (EO)3 nonionic surfactant. However, the gloss readings indicated there was still a substantial amount of residue. This residue, however, was spread evenly over the surface. On the dark colored high glossy highly hydrophobic surfaces, composition 4 still left a visible, more evenly (compared with formula 3) spread residue. The D gloss value on this black glossy ceramic tile was 3.2.
[0033] Composition 5 (magnesium ions added) gave further improved end results on the glossy tiles. Via adding Mg salts and anionic surfactant the residuality further decreased, despite a higher total level of actives. The D gloss value on the Black glossy ceramic tiles was 2.0.
| 6 | 7 | |
| NaPS | 5 | 3 |
| MgSO4. 7 H₂O | 2 | 1.5 |
| C13-15 (EO)30 | 5 | 6 |
| C12-13 (EO)3 | 3 | - |
| C8-10 (EO)5 | 10 | 15 |
| C8 alkyl sulphate | 10 | - |
| 2-hexyl decanol | 1 | 1 |
| palm kernel fatty acid | 0.5 | 1 |
| water/minors | balance | balance |
1. The use, in a composition for the cleaning of hard surfaces, said composition comprising
an anionic surfactant system, of magnesium ions as counterions for said anionic surfactant
system, whereby the residuality of said cleaning composition on said surfaces is reduced.
2. A composition suitable for use according to claim 1 which comprises an anionic surfactant
system, said composition comprising a short chain surfactant comprising a C6-10 alkyl
chain, said composition further comprising magnesium ions as counterions for said
anionic surfactant system.
3. A composition or use according to the preceding claims wherein said short chain surfactant
is an anionic surfactant.
4. A composition or use according to the preceding claims wherein said short chain surfactant
is a nonionic surfactant.
5. A composition or use according to the preceding claims wherein said composition is
a concentrated composition comprising from 10% to 80% by weight of the total composition
of water, preferably from 15% to 75%, most preferably from 30% to 75%.
6. A composition or use according to the preceding claims, wherein said composition comprises
from 0.5% to 50% by weight of the total composition of said anionic surfactant system,
preferably from 1% to 20%.
7. A composition or use according to the preceding claims wherein said anionic surfactant
system comprises alkyl sulfates or alkyl sulfonates, or mixtures thereof.
8. A composition or use according to the preceding claims wherein the molar ratio of
said magnesium ions to said anionic surfactant is 1:2.
9. A composition or use according to the preceding claims wherein said magnesium is provided
in the form of magnesium sulfate.