EP2094827A1

EP2094827A1 - Dishwashing composition

Info

Publication number: EP2094827A1
Application number: EP07857298A
Authority: EP
Inventors: Giuseppe Vincenzo Bolzoni; Marco Galli; Rita Lodola; Annalisa Schiavina; Giovanni Taino
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 2006-12-20
Filing date: 2007-12-07
Publication date: 2009-09-02
Anticipated expiration: 2027-12-07
Also published as: DE602007010030D1; PH12009501234B1; AR064483A1; PL2094827T3; BRPI0722091B1; RU2454456C2; MY144295A; VN21741A1; BRPI0722091A2; AU2007336423A1; CL2007003753A1; JP2010513624A; WO2008074667A1; RU2009127828A; EP2094827B1; EP2094827B2; AU2007336423B2; ATE485357T1; CA2670347A1

Abstract

The present invention relates to cleaning compositions, to their preparation, to cleaning methods and to processes for enhancing the retention of cleaning agents into carriers. More specifically, the invention relates to cleaning compositions for use in hand dishwashing. It is an object to provide a cleaning composition with enhanced retention of its cleaning agents (surfactants) in a carrier when being diluted. It has now been found that an improved and economical dilution thickening system may be obtained by a dilution-thickening surfactant system.

Description

DISHWASHING COMPOSITION

Field of the invention

The present invention relates to cleaning compositions, to their preparation, to cleaning methods and to processes for enhancing the retention of cleaning agents into carriers. More specifically, the invention relates to cleaning compositions for use in hand dishwashing.

Background prior art Liquid household cleaning products that provide thickening upon dilution are known in the art, as detailed in the following references:

US 5,922,664 describes a composition comprising a micellar dispersion of a mixture of at least two anionic surfactants having different resistance to electrolytic salting out, and alkali metal citrate. The attained viscosity upon dilution does not go beyond 1 ,400 mPas.

EP 314,232 mentions a composition of: (a) a primary surfactant chosen from amine, amine oxide, betaine or quaternary ammonium compounds, preferably an amine oxide, (b) a hydrotrope co-surfactant compound, e.g. ethanol, methanol or triethanol- amine, and (c) a water-ionisable non-surfactant compound, e.g. inorganic acids, neutral salts or alkali.

WO 96/32464 discloses a kit comprising a sponge and a water-thickening surfactant composition based on electrolyte concentration. This document also shows the viscosity profile of the disclosed compositions, wherein the viscosity peak reaches 1 ,685 mPas, which is only 2.7 times higher than the initial viscosity of 620 mPas.

In short, prior art documents teach simple compositions that can reach high viscosities upon dilution, improving its use in situations similar to manual dishwashing. In co-pending application PCT/EP2006/007038, a dilution thickening system is disclosed, based on a surfactant mixture and electrolyte.

However, prior art compositions present technical and/or economical bottlenecks that are solved by the present invention, such as obtaining cleaning compositions having enhanced retention in a carrier and/or high viscosity upon dilution, even at high dilution rates. Enhanced retention in the carrier provides controlled release of the composition.

Thus it is an object to provide a cleaning composition with enhanced retention of its cleaning agents (such as surfactants) in a carrier when being diluted.

It is another object of the invention to provide a composition with a lower consumption rate in use, thus giving better yield, being more economical in use and being environmentally friendly, than the compositions of the prior art.

It is a further object to provide enhanced retention of cleaning agent in a carrier, thereby decreasing the time spent in refilling the carrier, so that the cleaning compositions are faster and more efficient in use.

It is yet another object of the invention to allow a more rational use of containers for cleaning compositions.

It has now been surprisingly found that an improved and economical dilution thickening system may be obtained by a dilution-thickening surfactant system.

Summary of the invention

Accordingly, the invention provides A dilution-thickening aqueous liquid cleaning composition comprising 5-50%w of dilution-thickening surfactant system comprising: - 40-85%w Alkyl ether sulphate (0-4 EO)

- 0.01 -50%w Linear alkylbenzene sulphonate; and

- 0.01 -55%w Betaine; The invention further provides a method to clean hard surfaces comprising the steps of:

- contacting a carrier with a composition according to the invention; - treating the combination of carrier and composition with water; and

- performing a cleaning operation of a surface with the carrier.

The invention further provides a dilution-thickening surfactant system comprising:

- 40-85%w Alkyl ether sulphate (0-4 EO) - 0.01 -50%w Linear alkylbenzene sulphonate

- 0.01 -55%w Betaine; adding up to a 100%.

The invention also provides the use of the dilution thickening surfactant system of the invention in a dish washing composition.

These and other aspects, features and advantages will become apparent to those of ordinary skill in the art from a reading of the following detailed description and the appended claims. For the avoidance of doubt, any feature of one aspect of the present invention may be utilised in any other aspect of the invention. It is noted that the examples given in the description below are intended to clarify the invention and are not intended to limit the invention to those examples per se. Similarly, all percentages are weight/weight percentages unless otherwise indicated. Numerical ranges expressed in the format "from x to y" are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format "from x to y", it is understood that all ranges combining the different endpoints are also contemplated.

Description of the figure Figure 1 shows a ternary diagram of the dilution-thickening surfactant system of the invention. The shaded area shows the preferred concentrations of the three ingredients of the dilution-thickening surfactant system of the invention. The dashed line in the ternary diagram shows the approximate boundary for structured liquids on the bottom/right side of the dashed line and non-structured liquids on the top/left side of the dashed line. The double headed arrow shows performance vs cost; although the dilution thickening effect is obtained everywhere in the shaded area, the performance and cost increase towards the right side.

Detailed description of the invention

The invention provides a dilution-thickening surfactant system and cleaning compositions using the same.

The most suitable cleaning compositions have a low viscosity in concentrated form (i.e. in the bottle), and a high viscosity when diluted on the application device, such as a sponge; eventual the composition is released by application to a surface.

Dilution-thickening surfactant system

The thickening surfactant provides a surfactant system that has a low viscosity in concentrated form, and increasing viscosity when diluting up to a maximum viscosity (or a viscosity peak) and a decreasing viscosity upon further dilution.

The dilution-thickening surfactant system comprises alkyl ether sulphate (AES) optionally ethoxylated with 0-4 EO groups, linear alkyl benzene sulphonate (LAS) and betaine. Depending on the market a low-cost or premium dilution thickening system may be preferred as indicated herein below.

The dilution-thickening surfactant system is preferably not a structured liquid. It is also preferred that the composition is clear and transparent. Cloudy or hazy compositions are not preferred.

Alkyl ether sulphate The alkyl ether sulphates as defined herein are alkali metal, ammonium or alkanolammonium salts of Cs-Cis alkyl ether sulfates with 0 to 25 moles of alkylene oxide (thus also including Cs-Cis alkyl sulfates). The alkyl ether sulphates may be linear or branched. A common example of an alkyl ether sulphate is lauryl ether sulphate, preferably sodium lauryl ether sulphate (SLES).

The alkyl ether sulphate is present in the dilution-thickening surfactant system in a concentration of at least 40%, preferably at least 50%, more preferably at least 55% by weight, but not more than 85%, preferably not more than 70%.

Betaine

Betaines are a class of zwitterionic surfactants. The preferred betaines are carboxybetaines such as (dodecyldimethylammonium)acetate (lauryl betaine), (tetradecyldimethylammonium)acetate (myhstyl betaine), (cocodimethylammonium)acetate (coconut betaine), (oleyldimethylammonium) acetate (oleyl betaine), (dodecyloxymethyldimethylammonium) acetate, (cocoamido- propyldimethylammonium)acetate (also known as cocoamido-propyl betaine or CAPB); the sulfoniumbetaines such as (dodecyldimethylsulfonium) acetate and 3- (cocodimethyl-sulfonium)-i -propane sulfonate and the phosphoniumbetaines such as 4-(trimethylphosphonium)-1 -hexadecane sulfonate, 3-(dodecyldimethylphosphonium)- 1 -propanesulfonate, 2-(dodecyldimethylphosphonium)-1 -ethane sulfate and mixtures thereof.

The betaine is present in the dilution-thickening surfactant system in a concentration of at least 0.01 %, preferably at least 5%, and for premium dilution-tickening compostions even at least 10%, but not more than 55%, preferably not more than 35%, or for low cost dilution-thickening compositions even not more than 20%.

LAS

The third ingredient of the dilution thickening is linear alkylbenzene sulphonate (LAS). LAS is present in the dilution-thickening surfactant system in a concentration of 0.01 - 50%w. In order to obtain the premium dilution-thickening effect, a LAS concentration of 0.1 -35%w is preferred. In order to get an economical composition, with a good dilution thickening effect at lower cost, a concentration of 25-45%w is preferred. A balance between premium performance and cost is found at the intermediate range of 15-25% w of LAS.

Aqueous liquid cleaning composition

The aqueous liquid cleaning compositions according to the invention, comprise the dilution-thickening surfactant system of the invention in a concentration of 5 - 50%w, preferably at least 10%w, more preferably at least 15%w, still more preferably at least 20%w, most preferably 25%w, but preferably not more than 40%w, more preferably not more than 35%w, most preferably not more than 30%w.

When used in the cleaning composition, the dilution-thickening surfactant system provides a viscosity profile of the cleaning composition showing low viscosity at high concentration (towards 100%) as well as low viscosity on high dilution (towards 0%), but a viscosity peak somewhere in between. The profile normally has the shape of a bell-curve.

The dilution-thickening surfactant system of the invention provides the shape of the curve, and is very suitable for use in a liquid cleaning composition. However, to improve the versatility of the composition, it is preferred to be able to influence the position of the peak, dependent on the concentration. In other words, it is preferred to be able to influence the position of the peak on the concentration scale. Preferably the peak viscosity of the diluted composition is reached at a concentration of surfactant system in diluent (such as water) between 30% and 70%, more preferably between 30% and 50% surfactant system in diluent. Furthermore, it is preferred that the peak viscosity is at least 5 times the initial viscosity, preferably at least 10 times.

Thus, the aqueous liquid cleaning composition may further comprise viscosity modulating agents. The low viscosity in concentrated form helps the composition to easily penetrate a carrier, such as a sponge. Preferably, the undiluted composition has a viscosity below 1500mPas, more preferably 800-1250 mPas. Wherein the viscosity is determined at 25⁰C, using a Haake VT550A/T500 viscometer at 21 s^"1 with an MVII spindle. Electrolyte

In order to influence the position of the peak on the concentration scale, i.e. to move the peak between high and low concentration, the cleaning composition of the invention may comprise an electrolyte.

Electrolytes are water-soluble organic and inorganic salts (other than anionic surfactants), wherein the cation is chosen from alkali metals, alkaline earth metals, ammonium and mixture thereof and the anion is chosen from chloride, sulfate, phosphate, acetate, nitrate and mixtures thereof. Particularly useful are Magnesium, potassium, sodium and ammonium chloride and/or sulphate.

Preferably, the electrolyte is present in the cleaning composition in a concentration of 0-7.5%, more preferably 2.5-5%, still more preferably 3-4% by weight.

Viscosity modifying agent

In order to influence the viscosity of the cleaning composition, without moving the position of the peak on the concentration scale, a viscosity modifying agent may be added.

One suitable class of viscosity modifying agents is the class of nonionic surfactants. Nonionic surfactants reduce the viscosity of the concentrated cleaning composition, without moving the peak on the concentration scale.

The nonionics of the invention preferably have a HLB value (the hydrophilic/lipophilic balance) of at least 8, preferably at least 10, more preferably at least 12, but preferably not more than 16.

Suitable nonionic surfactants include the condensation products of hydrophobic alkyl, alkenyl, or alkyl aromatic compounds bearing functional groups having free reactive hydrogen available for condensation with hydrophilic alkylene oxide, such as ethylene oxide, propylene oxide, butylene oxide, polyethylene oxide or polyethylene glycol to form nonionic surfactants. Examples of such functional groups include hydroxy, carboxy, mercapto, amino or amido groups.

Examples of useful hydrophobes of commercial nonionic surfactants include Cs-Cis alkyl fatty alcohols, Cs-Ci₄ alkyl phenols, Cs-Cis alkyl fatty acids, Cs-Cis alkyl mercaptans, Cs-Cis alkyl fatty amines, Cs-Cis alkyl amides and Cs-Cis alkyl fatty alkanolamides. The polyoxyalkylene condensation products of such materials may comprise from 1 to 30 alkylene oxide groups, preferably from 5 to about 20 alkylene oxide groups, even more preferably from 8 to about 12 alkylene oxide groups. Accordingly, suitable ethoxylated fatty alcohols may be chosen from ethoxylated cetyl alcohol, ethoxylated ketostearyl alcohol, ethoxylated isotridecyl alcohol, ethoxylated lauric alcohol, ethoxylated oleyl alcohol and mixtures thereof.

Alternatively compounds from the group of propylene glycols, ethoxylated glycerols, and/or ethanol may be used as viscosity modifying agent. The most preferred propylene glycol is MPG (mono propylene glycol). The preferred ethoxylated glycerols have 3-15 ethylene oxide (EO) groups, more preferably 5-10 ethylene oxide groups.

Alternatively, this viscosity reducing effect may be obtained by the addition of other short chain organic alcohols. These solvents would have the same viscosity reducing effect as the nonionic surfactant, but are not preferred because they are considered "volatile organic compounds". Volatile organic compounds are not preferred in the context of the present invention.

Thus, nonionic surfactants are preferred in the cleaning compositions of the inventions, as they also have detergent properties.

Another commonly used ingredient in cleaning compositions are hydrotropes. Hydrotropes reduce the dilution thickening effect according to the invention. It is preferred to avoid hydroptropes such as sodium cumene sulphonate (SCS), sodium xylene sulphonate (SXS), anionic hydroptropes and polyethylene glycols. Generally, the viscosity modifying agent reduces the viscosity of the composition over the entire concentration scale. The viscosity modifying agent is optionally present in the cleaning composition in a concentration of 0-5%, preferably 0.1 -2%, more preferably 0.5-1.5%.

Further surfactants

The compositions my further comprise surfactants. However, such surfactant may have no or limited influence on the dilution thickening behaviour of the composition. Preferably said further surfactants do not move the peak more than 10% on the concentration scale and do not reduce or increase the peak viscosity by more than 20%. The cleaning compositions of this invention may further comprise selected from anionic, amphoteric, zwitterionic and nonionic surfactants and combinations thereof. Cation ic surfactants are not preferred.

Suitable further surfactants are described in "Surface Active Agents" Vol. 1 , by

Schwartz & Perry, lnterscience 1949, Vol. 2 by Schwartz, Perry & Berch, lnterscience 1958, in the current edition of "McCutcheon's Emulsifiers and Detergents" published by Manufacturing Confectioners Company or in "Tenside-Taschenbuch", H. Stache, 2nd Edn., Carl Hauser Verlag, 1981.

Optional Ingredients

The compositions of the invention optionally comprise other ingredients, such as fragrances, preservatives and colorants. Particularly colorants are useful to indicate the presence of the compositions in an absorbent carrier. Examples of useful colorants are: Blue FDC (CI:42090); Patent blue (CI:42051 ); Blue ABL 80 (Cl:61585);

Red punzo No 7 (Cl: 16255), Red Puricolor Are 14 (Cl: 14720), Yellow Tartrazine Cl 14190, Quinoline Yellow 47005, Brillant Black 28440,Sunset yellow Cl 15985, and mixtures thereof.

The present invention also discloses a method for cleaning domestic surfaces, particularly hard surfaces, using the cleaning compositions according to the invention. The cleaning method of the invention has several advantages over known methods. In one aspect, it provides less consumption of cleaning composition and is therefore more economical and environmentally friendly.

The cleaning method of the invention comprises the steps of: i) contacting a carrier with the composition of the invention; ii) treating the combination of carrier and composition with water; and iii) performing a cleaning operation of a surface with the carrier.

In an alternative, but less preferred variation, water can be added to the absorbent carrier before the composition is added to it.

A cleaning operation is typically represented by pressing the absorbent carrier to the surface and scrubbing it with circular movements, or in any other way, to aid in the removal of soil, grease or dirt from the surface. Dish surfaces and crockery are particular examples of household surfaces that can be cleaned with the composition of the invention.

Useful absorbent or porous carriers are known, particularly the ones comprising voids where liquid can be stored, for instance, sponges (natural, polymeric, steel, etc), scouring pads, cloths. The composition is particularly suitable to be applied onto sponges in the cleaning method.

The ratio between the amount of water and the amount of cleaning composition to be used in the cleaning method according to the invention is preferably from about 0.5 to about 5, more preferably about 0.5-4, most preferably up to about 3.5.

The invention further provides a process for enhancing the retention of cleaning agents into a carrier comprising the steps of: a) providing a solution of surfactants; b) providing a solution of viscosity modulating agent; c) mixing the solution of surfactants with the solution of viscosity modulating agent. Application methods and use

For hand dishwashing application of the cleaning compositions, such compositions preferably have a low viscosity initially and only increase in viscosity after addition of a certain amount of diluent. This allows penetration of the composition through the pores of a porous carrier (e.g. a sponge), while at the same time keeping the composition within the carrier for a longer period. The selective way by which the composition of the invention behaves provides an advantageous balance between low initial viscosity, maximum viscosity and final viscosity, as well as provides an advantageous balance between viscosity increasing ratio (between minimum and maximum viscosity) and viscosity decreasing ratio (between maximum and final viscosity).

In a preferred embodiment, the cleaning compositions of the invention comprise a dilution-thickening surfactant system and viscosity modulating agents and other optional ingredients and provide: low initial viscosity so as to easily penetrate into a carrier; viscosity increase upon dilution after penetrating into said carrier, so that the cleaning compositions stay longer within the carrier, thus providing enhanced performance even after repeatedly rinsing; on dilution the cleaning composition becomes a stable and transparent gel; and controlled and sustained release of surfactants.

In another aspect there is provided a cleaning method for surfaces, particularly hard surfaces, which is more efficient and economic than the previously known cleaning methods.

In yet another aspect there is provided a process for enhancing the retention of cleaning agents into carriers such as sponges and the like. The invention provides dilution-thickening aqueous liquid cleaning compositions comprising:

- one or more surfactants; - one or more viscosity modulating agents.

More specifically, the invention provides dilution-thickening aqueous liquid cleaning compositions comprising:

- one or more surfactants;

- at least one electrolyte as a viscosity modulating agent. The invention will now be illustrated by means of the following non limiting examples.

Examples

These examples show the performance the compositions of the invention vis-a-vis the prior art.

Example 1

In example 1 , the controlled release of the composition according to the invention is compared to commercially available products.

The composition according to the invention is given in the table below

^*) Minors are pH adjustment materials, perfume, dye and preservative The commercial products tested are Dixan (ex Henkel, purchased in Italy 27 February 2006), Fairy (ex Procter&Gamble, purchased in UK 1 September 2005) Sole (ex Reckitt Benckizer, purchased in Italy 12 April 2006) and Last (ex Bolton Manitoba, purchased in Italy 20 April 2006), see table below for an analysis of the compositions.

^*) Chain lengths and degree of ethoxylation are estimated; Minors include dye, perfume, solvents, preservatives etc

To determine the active dosing of the material 1 g of one of the compositions was applied directly onto a wet sponge suitable for cleaning dishes. The sponge was then rinsed with 50 ml demin water aliquots, by method of adding 50 ml of water to the sponge, squeezing the sponge and collecting the water. This was repeated with several aliquots of 50 ml water until no more detergent was released from the sponge.

The collected water was analysed to determine the concentration of released detergent product. And the amount of remaining active was calculated by deducting the measured amount of detergent product in each rinse from the starting amount and calculating the remain amount on the sponge. The results are given in the table below.

As can be clearly seen from the results table above, the composition of the invention gives a much more controlled release of active during a greater number of rinse steps.

Example 2

In example 2, the viscosity profile of a number of compositions according to the invention is demonstrated.

The compositions of this example are given in the table below.

^*) Coco amidopropyl betaine In the table below, the viscosity of the product is given at different dilutions. In this table, 100% represents the neat undiluted product, while the other percentages represent the percentage of product in water.

The results clearly show that the viscosity of the product is relatively low in undiluted form and also low when diluted down to about 30%, but that the viscosity between the neat composition and the highly dilution form of the composition is very high.

Example 3

In example 3, the effect of an additional viscosity modifying agent (MPG, composition 10) on the controlled release of the composition is demonstrated and compared with a similar composition without the additional viscosity modifying agent (composition 9) and a commercially available hand dish washing liquid (Lux Lemon). The compositions are given in the table below.

The product release was tested with the method as given in example 1. The release results are given in the table below

rinsing step water ( Comp 8 Comp 9 Comp 10

0 0 100 100 100

1 50 73 90 96

2 100 49 83 92

3 150 30 75 87

4 200 19 66 80

5 250 11 54 73

6 300 8 42 65

7 350 6 31 58

8 400 4 23 49

9 450 2 16 39

10 500 2 10 31

11 550 1 8 24

12 600 1 6 17

13 650 1 4 11

14 700 0 2 5

15 750 0 1 0

As can be clearly seen from the results in the table above, the composition with the additional viscosity modifying agent gives an even more controlled release of active during a greater number of rinse steps.

Claims

1. A dilution-thickening aqueous liquid cleaning composition comprising 5- 50%w of dilution-thickening surfactant system comprising:

(a) 40-85%w Alkyl ether sulphate (0-4 EO);

(b) 0.01 -50%w Linear alkylbenzene sulphonate; and

(c) 0.01 -55%w Betaine;

2. A cleaning composition according to claim 1 wherein the composition further comprises 0-7.5% of an electrolyte.

3. A cleaning composition according to any one of claims 1 or 2 wherein the composition further comprises 0-5% a viscosity modifying agent selected from nonionic surfactant, propylene glycols, ethoxylated glycerols, and/or ethanol.

4. A cleaning composition according to any one of claims 2 - 3 wherein the electrolyte is an alkali metal, alkaline earth or ammonium chloride, sulfate, phosphate, acetate, nitrate and mixtures thereof.

5. A Cleaning compositions according claim 4 wherein the electrolyte is magnesium sulfate.

6. A cleaning composition according to any one of claims 1 to 5 wherein the alkyl ether sulphate is a C10-C18 alkylether sulfate salt with 1-4 EO groups.

7. A cleaning composition according to any one of claims 1 to 6 wherein the betaine is Ci₀-Ci₈ alkylamidopropyl betaine.

8. A cleaning composition according to any one of claims 1 to 7 wherein the initial viscosity is between below 1500mPas and which on dilution to 30- 70% reach a peak viscosity of at least 5 times the initial viscosity.

9. Method to clean hard surfaces comprising the steps of:

(a) contacting a carrier with a composition according to any one of claims 1 to 8;

(b) treating the combination of carrier and composition with water; and

(c) performing a cleaning operation of a surface with the carrier.

10. A dilution-thickening surfactant system comprising:

(a) 40-85%w Alkyl ether sulphate (0-4 EO)

(b) 0.01 -50%w Linear alkylbenzene sulphonate

(c) 0.01 -55%w Betaine;

11. Use of the dilution thickening surfactant system according to claim 10 in a dish washing composition.