WO2025131532A1

WO2025131532A1 - An aqueous liquid detergent composition comprising rhamnolipid biosurfactant

Info

Publication number: WO2025131532A1
Application number: PCT/EP2024/083170
Authority: WO
Inventors: Robert John Carswell; Oliver Jonathan Deane; Arran MASON; Adam Mcdonald
Original assignee: Unilever Global IP Ltd; Unilever IP Holdings BV; Conopco Inc
Current assignee: Unilever Global IP Ltd; Unilever IP Holdings BV; Conopco Inc
Priority date: 2023-12-20
Filing date: 2024-11-21
Publication date: 2025-06-26
Anticipated expiration: 2026-06-20

Abstract

The present invention relates to aqueous liquid detergent compositions comprising: a surfactant system comprising: (i) a primary surfactant mix comprising alkyl ether sulfate surfactant and alkyl sulfate surfactant; (ii) an amphoteric surfactant selected from betaines, glucamides and sultaines; and (iii) rhamnolipid biosurfactant; wherein - the weight ratio of (alkyl ether sulfate surfactant + alkyl sulfate surfactant) / amphoteric surfactant is from 4.5 to 1; and - the percentage of alkyl sulfate surfactant calculated on total amount of alkyl sulphate and alkyl ether sulfate is from 45 to 95. The invention further relates to a method of cleaning a hard surface using the composition of the invention, as well as the use of said surfactant mix to improve foaming behaviour in an aqueous liquid detergent composition comprising rhamnolipid surfactant.

Description

An Aqueous Liquid Detergent Composition Comprising Rhamnolipid Biosurfactant

Field of the Invention

The present invention relates to aqueous liquid detergent compositions comprising rhamnolipid biosurfactant, in particular a hand dishwash liquid detergent compositions comprising a surfactant system providing for good foam characteristics and cleaning performance.

Background of the Invention

Household cleaning activities involve the use of a detergent product and often water to rinse-off the detergent product and finish the cleaning process. These activities are typically performed daily, often more than once a day, such as dish washing. That is, hard surface cleaning, dishwashing and other household cleaning activities are time consuming activities and, ideally, can be optimized when using products with improved cleaning performance.

A cleaning product often comprises a surfactant system containing different types of surfactants to provide for cleaning efficacy. Therefore, some cleaning products contain a main surfactant, sometimes referred to as primary surfactant, and further surfactant, sometimes referred to as co-surfactant or secondary surfactant.

Consumers are interested in the sensorial experience of a detergent product and it's use in the washing process, both during and immediately after use, like for example the lasting sensorial impression left on the hands. This is important as the handwash process involves the consumer's hands being in contact with the detergent product and resulting wash liquor, and the formulation can be harsh on the skin.

WO 2020/016097 discloses the use of rhamnolipid surfactants in a surfactant system for handwash detergents to confer to the consumer a sensorial impression of mildness on the hands.

Consumers are also sensitive to visual cues when using a cleaning product like for example a hand dish wash product. One of the more prominent visual cues is foam formation when cleaning, as the amount of foam is often seen as an indicator of cleaning performance. More foam is usually interpretated as more cleaning power. And when no foam is formed when washing up, the user may think the cleaning liquid used is not able to clean anymore. Typical use of a hand dishwash cleaning product includes the preparation of a wash liquor by adding the detergent product to a volume of water, the foam so created is herein referred to as flash-foam, i.e. foam being created in the absence of soil. The wash liquor is then used to clean items like for examples soiled plates and by doing so introduces soil into the wash liquor. The foam present after the addition of said soil is herein referred to as yield-foam and is an indicator of the ability of the cleaning detergent to withstand soil addition. The wash liquor now contains soil and the foam created by further agitating the wash liquor is herein referred to as build-foam.

Consumers may understand flash-foam as an indicator of the overall detergency quality of the detergent product, yield-foam as an indicator of the quality of the actual cleaning process of an item and build-foam as an indicator of the continuing ability of the wash liquor to clean. An increase in the amount of build-foam compared to the amount of flash-foam (build foam/flash foam) reassures the consumer that the wash liquid can still be used. Some consumers may find this more important than the absolute foam level.

Inclusion of rhamnolipid surfactants may negatively influence the foam formation in a surfactant system.

Although some consumers prefer adequate foam formation during use, the foam should also be easy to rinse away as consumers sometimes have to use excessive amounts of clean water to achieve the same. This is sometimes referred to as ‘easy rinse’ and refers to a reduced amount of water required to rinse away foam at the end of the cleaning process.

Nowadays, some consumers prefer cleaning products with an improved environmental profile. That is, they prefer products that are ‘eco-friendly’ and have a reduced or no impact on the environment when the product is used but also when the product is manufactured. Some consumers still associate ‘eco-friendly’ cleaning products with less efficacious cleaning products.

To address these developing consumer preferences, use of certain surfactants can be reduced or avoided altogether, like e.g. sulphonated surfactants like alkylbenzene sulphonates. Another way of addressing these consumer preferences is by lowering the total amount of surfactant in a product. However, these changes may negatively influence cleaning efficacy or other aspects of the consumer experience of the detergent product. In view of the above, there remains a need for aqueous liquid detergent compositions comprising rhamnolipid surfactant without compromising consumer satisfaction in terms of environmental profile and/or foam profile and/or sensorial experience.

Summary of the Invention

We have found that aqueous liquid detergent compositions comprising rhamnolipid biosurfactants comprising a specific surfactant system provide for detergent compositions that leave a sensorial impression of mildness on the hands but still have a good foaming profile.

Accordingly, in a first aspect the invention relates to an aqueous liquid detergent composition comprising:

(a) from 3 to 30 wt% of a surfactant system comprising:

(i) a primary surfactant mix comprising alkyl ether sulfate surfactant and alkyl sulfate surfactant;

(ii) an amphoteric surfactant selected from betaines, glucamides and sultaines; and

(iii) from 0.25 to 5 wt% rhamnolipid biosurfactant;

(b) from 0.05 to 5 wt% of an inorganic salt selected from sodium chloride, magnesium sulphate and sodium sulphate; wherein the weight ratio of (alkyl ether sulfate surfactant + alkyl sulfate surfactant) I amphoteric surfactant is from 4.5 to 1; and the percentage of alkyl sulfate surfactant calculated on total amount of alkyl sulphate and alkyl ether sulfate is from 45 to 95.

Preferably the composition is an aqueous liquid hand dishwash detergent composition.

The invention further relates to a method of cleaning a hard surface using the composition of the invention, as well as the use thereof.

Detailed Description of the Invention

Any feature of one aspect of the present invention may be utilized in any other aspect of the invention. The word “comprising” is intended to mean “including” but not necessarily “consisting of” or “composed of.” In other words, the listed steps or options need not be exhaustive. Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and/or use are to be understood as modified by the word “about”. 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 "x to y", it is understood that all ranges combining the different endpoints are also contemplated. Unless specified otherwise, amounts as used herein are expressed in percentage by weight based on total weight of the composition and is abbreviated as “wt%”. The use of any and all examples or exemplary language e.g. “such as” provided herein is intended merely to better illuminate the invention and does not in any way limit the scope of the invention otherwise claimed. Room temperature is defined as a temperature of about 20° Celsius.

The composition of the present invention is an aqueous cleaning composition, that is to say, the composition comprises water. The amount of water will depend on the desired concentration of the other ingredients. Preferably the composition comprises 70 to 97 wt% water, more preferably not less than 65 wt%, still more preferably not less than 70 wt% but typically not more than 97 wt%, more preferably not more than 95 wt%, still more preferably not more than 90 wt%.

The composition is liquid, that is, it can be poured. Compositions of the present invention preferably have a viscosity in the range of 500 to 3500 cps at 21 sec¹ measured on a Haake Viscometer (Models include VT181, VT501 , VT550 or equivalent) with “cup” and “bob” geometry, equipped with a MV cup and a MV2 bob at a controlled temperature of 25°C. Preferably 1500 to 2500, like for example 1600 to 2400 and more preferably 1700 to 2300. Thicker compositions are sometimes preferred by users as these may be easier to dose. For compositions with lower amounts of surfactant, a thick product may also validate appropriate cleaning power perception with users of such compositions.

Surfactant System

The composition of the present invention comprises a surfactant system. The surfactant system comprises at least a primary surfactant mix comprising alkyl ether sulfate surfactant and alkyl sulfate surfactant; an amphoteric surfactant and rhamnolipid biosurfactant.

The surfactant system is present in the composition in a concentration of 3 to 30 wt%.

Preferably the weight ratio of the surfactant system is 3 to 20 wt%, more preferably 4 to 15 wt% and even more preferably 5 to 10 wt%. Primary surfactant mix

The surfactant system comprises a primary surfactant mix comprising alkyl ether sulfate surfactant and alkyl sulfate surfactant.

Preferred alkyl ether sulfate surfactants are ones of the formula (Formula I):

(Ri-(OR’)_n-O-SO3')xM^x+, wherein:

Ri is saturated or unsaturated C8-C16, preferably C12-C14 alkyl chain; preferably, Ri is a saturated C8-C16, more preferably a saturated C12-C14 alkyl chain;

R’ is ethylene; n is from 1 to 15, preferably from 1 to 10, more preferably from 1 to 5, even more preferably from 1 to 3; x is equal to 1 or 2;

M^x+ is a suitable cation which provides charge neutrality, preferably sodium, calcium, potassium, or magnesium, more preferably a sodium cation.

Preferably, the alkyl ether sulfate surfactant comprises alkyl ether sulfate having 1 to 3 ethylene oxide units per molecule, more preferably 1 to 2 ethylene oxide units per molecule. Preferably the alkyl ether sulfate surfactant comprises lauryl ether sulfate having 1 to 2 ethylene oxide units per molecule.

The primary surfactant further comprises alkyl sulfate surfactant. Preferably according to the formula (Formula II):

(RI-O-SC>3')XM^X+, wherein:

Ri is saturated or unsaturated C8-C16, preferably C12-C14 alkyl chain; preferably, Ri is a saturated C8-C16, more preferably a saturated C12-C14 alkyl chain; x is equal to 1 or 2; M^x+ is a suitable cation which provides charge neutrality, preferably sodium, calcium, potassium, or magnesium, more preferably a sodium cation.

Examples of alkyl sulfate surfactant include sodium lauryl sulphate. Suitable examples include alkyl sulphates from synthetic origin with trade names Safol 23, Dobanol 23A or 23S, Lial 123 S, Alfol 1412S, Empicol LC3, Empicol 075SR. Further suitable examples, and preferred, include alkyl sulphates commercially available from natural sources with trade names Galaxy 689, Galaxy 780, Galaxy 789, Galaxy 799 SP.

The percentage of alkyl sulfate surfactant calculated on total amount of alkyl sulphate and alkyl ether sulfate is from 45 to 95. Preferably the percentage of alkyl sulfate surfactant calculated on total amount of alkyl sulphate and alkyl ether sulfate is from 50 to 80, more preferably 55 to 70.

Primary surfactant may be present in a concentration of 35 to 85 wt%, preferably 40 to 80 wt%, more preferably 45 to 75 wt%, even more preferably 50 to 70 wt% by total weight of the surfactant system.

Some consumers prefer surfactants that are not synthetically made but that are more natural in nature. Anionic surfactants with branched alkyl chain can only be made synthetically. Linear alkyl chains can be plant derived and can be seen as more natural.

Preferably the primary surfactant mix comprises at least 75% by weight (as calculated on total amount of primary surfactant mix) of linear alkyl chain surfactant. By alkyl chain is meant the total amount of Ri in Formula I and II as defined above. More preferably at least 85%, even more preferably at lest 95% and most preferably only linear alkyl chains are present.

Preferably the primary surfactant mix has a weight average degree of branching of less than 30%, more preferably less than 20% and even more preferably less than 10%.

The weight average degree of branching is defined according to the following formula:

Weight average of branching (%)= [(xl * wt% branched alcohol 1 in alcohol 1 + x2 * wt% branched alcohol 2 in alcohol 2 + ....) / (xl + x2 + ....)] * 100 wherein x1, x2, are the weight in grams of each alcohol in the total alcohol mixture of the alcohols which were used as starting material for the surfactant for the detergent of the invention. In the weight average branching degree calculation, the weight of surfactant components in the primary surfactant mix not having branched groups should also be included. ic surfactant

The surfactant system comprises amphoteric surfactant selected from betaines, glucamides and sultaines.

Preferably the amphoteric surfactant comprises at least 70 wt%, calculated on total amount of amphoteric surfactant, of betaine. More preferably at least 80 wt%, even more preferably at least 90 wt% and still more preferably at least 95 wt%. It may be preferred that the amphoteric surfactant consists of betaine.

Preferably amphoteric surfactant is present in a concentration of 20 to 35 wt% by total weight of the surfactant system.

Betaine

Preferably the amphoteric surfactant comprises betaine. Suitable betaines include alkyl betaine, alkyl amido betaine, alkyl amidopropyl betaine, alkyl sulphobetaine and alkyl phosphobetaine, wherein the alkyl groups preferably have from 8 to 19 carbon atoms.

Examples include cocodimethyl sulphopropyl betaine, cetyl betaine, laurylamidopropyl betaine, caprylate/caprate betaine, capryl/capramidopropyl betaine, cocam idopropyl hydroxysultaine, cocobutyramido hydroxysultaine, and preferably lauryl betaine, cocamidopropyl betaine and sodium cocamphopropionate. Preferably the betaine is cocamidopropyl betaine (CAPB). The weight ratio of (alkyl ether sulfate surfactant + alkyl sulfate surfactant) I amphoteric surfactant is from 4.5 to 1; and preferably is from 4 to 1 , more preferably from 3.5 to 1.5.

It was surprisingly found that the surfactant system according to the present invention allows for inclusion of rhamnolipid biosurfactant without compromising on foam profile.

Rhamnolipid biosurfactant

The surfactant system comprises from 0.25 to 5 wt% rhamnolipid biosurfactant, preferably from 0.25 to 3 wt% and more preferably from 0.5 to 2 wt% rhamnolipid biosurfactant. Rhamnolipid biosurfactants are a class of glycolipid. They are constructed of rhamnose combined with beta-hydroxy fatty acids. Rhamnose is a sugar. Fatty acids are ubiquitous in animals and plants.

Rhamnolipids are discussed in Applied Microbiology and Biotechnology (2010) 86:1323-1336 by E. Deziel et al. Rhamnolipids are produced by Evonik, Stepan, Glycosurf, AGAE Technologies and Urumqi Unite Bio-Technology Co., Ltd. Rhamnolipids may be produced by strains of the bacteria Pseudomonas Aeruginosa. There are two major groups of rhamnolipids; mono-rhamnolipids and di-rhamnolipids.

Mono-rhamnolipids have a single rhamnose sugar ring. A typical mono-rhamnolipid produced by P. aeruginosa is L-rhamnosyl-p-hydroxydecanoyl-p-hydroxydecanoate (RhaC C ). It may be referred to as Rha-Cio-C , with a formula of C26H48O9. Mono-rhamnolipids have a single rhamnose sugar ring.

The IUPAC Name is 3-[3-[(2R,3R,4R,5R,6S)-3,4,5-trihydroxy-6-methyloxan-2- yl]oxydecanoyloxy]decanoic acid.

Di-rhamnolipids have two rhamnose sugar rings. A typical di-rhamnolipid is L-rhamnosyl-L- rhamnosyl-p-hydroxydecanoyl-p-hydroxydecanoate (Rha2C Cio). It may be referred to as Rha-Rha-C-10-C-w, with a formula of C32H58O13.

The IUPAC name is 3-[3-[4,5-dihydroxy-6-methyl-3-(3,4, 5-tri hydroxy-6-methyloxan-2- yl)oxyoxan-2-yl]oxydecanoyloxy]decanoic acid.

In practice a variety of other minor components with different alkyl chain length combinations, depending upon carbon source and bacterial strain, exist in combination with the above more common rhamnolipids. The ratio of mono-rhamnolipid and di-rhamnolipid may be controlled by the production method. Some bacteria only produce mono-rhamnolipid, see US5767090: Example 1, some enzymes can convert mono-rhamnolipid to di-rhamnolipid.

In various publications mono-rhamnolipids have the notation Rha-, which may be abbreviated as Rh or RL2. Similarly, di-rhamnolipids have the notation Rha-Rha or Rh-Rh- or RL1. For historical reasons "rhamnolipid 2" is a mono-rhamnolipid and "rhamnolipid 1 " is a di- rhamnolipid. This leads to some ambiguity in the usage or "RL1 " and "RL2" in the literature. Throughout this patent specification, we use the terms mono- and di-rhamnolipid in order to avoid this possible confusion. However, if abbreviations are used R1 is mono-rhamnolipid and R2 is di-rhamnolipid. For more information on the confusion of terminology in the prior art see the introduction to US 4814272.

The following rhamnolipids have been detected as produced by the following bacteria: (C12: 1 , C14:1 indicates fatty acyl chains with double bonds).

Rhamnolipids produced by P. aeruginosa (mono-rhamnolipids):

Rha-C8-C10, Rha-C10-C8, Rha-C-10-C10, Rha-C10-C12, Rha-C10-C12:1 , Rha-C12-C10, Rha-C12:1-C10

Rhamnolipids produced by P. aeruginosa (di-rhamnolipids):

Rha-Rha-C8-C10, Rha-Rha-C8-C12:1 , Rha-Rha-C10-C8, Rha-Rha-C10-C10, Rha-Rha-C10- C12:1 , Rha- Rha-C-10-C-12, Rha-Rha-C-12-C-10, Rha-Rha-C-12:1-C-12, Rha-Rha-C-10- C14:1.

Rhamnolipids produced by P. aeruginosa (unidentified as either mono- or di-rhamnolipids): C8-C8, C8-C10, C10-C8, C8-C12:1 , C12:1-C8, C10-C10, C12-C10, C12:1-C10 C12-C12, C12:1-C12, C14-C10, C14:1-C10, C14-C14.

Rhamnolipids produced by P. chlororaphis (mono-rhamnolipids only):

Rha-C10-C8, Rha-C10-C10, Rha-C12-C10, Rha-C12:1-C10, Rha-C12-C12, Rha-C12:1-C12, Rha-C14-C10. Rha-C-14:1- C-10.

Rhamnolipids produced by Burkholdera pseudomallei (di-rhamnolipids only): Rha-Rha-C14-C14.

Rhamnolipids produced by Burkholdera (Pseudomonas) plantarii (di-rhamnolipids only): Rha-Rha-C14-C14.

There are over 100 strains of P. aeruginosa on file at the American Type Culture Collection (ATCC). There are also a number of strains that are only available to manufacturers of commercial Rhamnolipids. Additionally, there are probably thousands of strains isolated by various research institutions around the world. Some work has gone into typing them into groups. Each strain has different characteristics including how much rhamnolipid is produced, which types of rhamnolipids are produced, what it metabolizes, and conditions in which it grows. Only a small percentage of the strains have been extensively studied.

Through evaluation and selection, strains of P. aeruginosa can be isolated to produce rhamnolipids at higher concentrations and more efficiently. Strains can also be selected to produce less byproduct and to metabolize different feedstock or pollutants. This production is greatly affected by the environment in which the bacterium is grown.

A typical di-rhamnolipid is L-rhamnosyl-L-rhamnosyl-p-hydroxydecanoyl-p-hydroxydecanoate (Rha₂CioC with a formula of C32H58O13).

Preferably the rhamnolipid is selected from:

Rhamnolipids produced by P. aeruginosa (mono-rhamnolipids):

Rha-C8-C10, Rha-C10-C8, Rha-C10-C10, Rha-C10-C12, Rha-C10-C12:1, Rha-C12-C10, Rha- C12:1-C10

Rhamnolipids produced by P. chlororaphis (mono-rhamnolipids only):

Rha-C10-C8, Rha-C10-C10, Rha-C12-C10, Rha-C12:1-C10, Rha-C12-C12, Rha-C12:1-C12, Rha-C14-C10, Rha-C14:1-C10.

Mono-rhamnolipids may also be produced from P.putida by introduction of genes rhIA and rhIB from Psuedomonas aeruginosa [Cha et al. in Bioresour Technol. 2008. 99(7):2192-9] Rhamnolipids produced by P. aeruginosa (di-rhamnolipids):

Rha-Rha-C8-C10, Rha-Rha-C8-C12:1 , Rha-Rha-C10-C8, Rha-Rha-C10-C10, Rha-Rha-C10- C12:1 , Rha-Rha-C10-C12, Rha-Rha-C12-C10, Rha-Rha-C12:1-C12, Rha-Rha-C10-C14:1

Rhamnolipids produced by Burkholdera (Pseudomonas) plantarii (di-rhamnolipids only): Rha-Rha-C14-C14. Rhamnolipids produced by P. aeruginosa which are initially unidentified as either mono- or di-rhamnolipids:

C8-C8, C8-C10, C10-C8, C8-C12:1, C12:1-C8, C10-C10, C12-C10, 012:1-010, C12-C12, 012:1-012, C14-C10, 014:1-010, C14-C14.

Most preferably the Rhamnolipid is L-rhamnosyl-p-hydroxydecanoyl-p-hydroxydecanoate (RhaC C with a formula of C26H48O9) produced by P. aeruginosa.

Preferably, the rhamnolipid comprises at least 50 wt.% mono-rhamnolipid, more preferably at least 60 wt.% mono-rhamnolipid, even more preferably 70 wt.% mono-rhamnolipid, most preferably at least 80 wt.% mono-rhamnolipid; alternatively, wherein the rhamnolipid comprises at least 50 wt.% di-rhamnolipid, more preferably at least 60 wt.% di-rhamnolipid, even more preferably 70 wt.% di-rhamnolipid, most preferably at least 80 wt.% di-rhamnolipid.

Preferably the rhamnolipid is a di-rhamnolipid of formula: Rha2C8-i2Cs-i2. The preferred alkyl chain length is from Cs to C12. The alkyl chain may be saturated or unsaturated.

Further surfactants

The surfactant system of the present invention may comprise other surfactants in addition to the primary surfactant, amphoteric surfactant and rhamnolipid biosurfactant, like for example other anionic surfactants. The surfactant system may also comprise cationic and/or non-ionic surfactant.

Suitable non-ionic surfactants include the condensation products of a higher alcohol (e.g. an alkanol containing about 8 to 18 carbon atoms in a straight or branched chain configuration) condensed with about 5 to 30 moles of ethylene oxide, for example, lauryl or myristyl alcohol condensed with about 16 moles of ethylene oxide (EO), tridecanol condensed with about 6 moles of EO, myristyl alcohol condensed with about 10 moles of EO per mole of myristyl alcohol, the condensation product of EO with a cut of coconut fatty alcohol containing a mixture of fatty alcohols with alkyl chains varying from 10 to about 14 carbon atoms in length and wherein the condensate contains either about 6 moles of EO per mole of total alcohol or about 9 moles of EO per mole of alcohol and tallow alcohol ethoxylates containing 6 EO to 11 EO per mole of alcohol. Particularly preferred is Lauryl alcohol condensed with 5, 7 and 9 moles of ethylene oxide (Laureth 5, Laureth 7 and Laureth 9). Preferably, the non-ionic surfactant is selected from Laureth 5, Laureth 7 and Laureth 9, or mixtures thereof. Condensates of 2 to 30 moles of ethylene oxide with sorbitan mono- and tri-C10-C20 alkanoic acid esters having a H LB of 8 to 15 also may be employed as the nonionic surfactant. These surfactants are well known and are available from Imperial Chemical

Industries under the Tween trade name. Suitable surfactants include polyoxyethylene (4) sorbitan monolaurate, polyoxyethylene (4) sorbitan monostearate, polyoxyethylene (20) sorbitan trioleate and polyoxyethylene (20) sorbitan tristearate.

Another nonionic surfactant that may be employed are alkyl polyglycosides. These may be preferred as these have because of their environmentally friendly profile.

When present, the non-ionic surfactant is in a concentration of 0.1 to 5 % by weight, preferably at least 0.3%, still more preferably at least 0.5% but preferably not more than 4%, more preferably not more than 3%, even more preferably not more than 2% by weight of the surfactant system.

Some surfactants are known to have other functions as well and are sometimes classified as such although it is commonly known that such ingredients are also surfactants. For example, benzalkonium chloride (BKC) is a known cationic surfactant that can also be employed as an antimicrobial agent. For the purpose of the present invention such ingredients are taken into account for the calculation of weight percentages of surfactant.

Alkylbenzene sulphonate (ABS) is an anionic surfactant that is not readily available from renewable carbon or biorenewable carbon sources and some consumers may prefer compositions that only have a limited amount of such surfactant or are entirely free thereof.

Therefore, the surfactant system optionally comprises alkylbenzene sulphonates or derivatives thereof wherein the amount of alkylbenzene sulphonate or derivatives thereof is up to 25 wt% of the anionic surfactant calculated on total amount of anionic surfactant. Preferably up to 20 wt%, more preferably up to 15 wt%, and even more preferably up to 10 wt%.

Preferably the surfactant system of the present composition is free of alkylbenzene sulphonates and derivatives thereof.

Alkylbenzene sulphonates (ABS) and derivatives thereof include water-soluble alkali metal salts of organic sulphonates having alkyl radicals typically containing from about 8 to about 22 carbon atoms, preferably 8 to 18 carbon atoms, still more preferably 12 to 15 carbon atoms and may be saturated or unsaturated. Examples include sodium salt of linear alkylbenzene sulphonate, alkyl toluene sulphonate, alkyl xylene sulphonate, alkyl phenol sulphonate, alkyl naphthalene-sulphonate, ammonium diamylnaphthalene-sulphonate and sodium dinonylnaphthalene-sulphonate and mixtures with olefin sulphonates.

More preferably the surfactant system of the composition of the present invention is free of any sulphonated surfactant.

Cleaning polymer

The liquid detergent composition of the present invention may optionally comprise a cleaning polymer. Typical examples of cleaning polymers include hydrophobically modified polymers, alkoxylated polyalkyleneimines, polyamines and polyethyleneoxides.

Preferably the cleaning polymer is a polyethylene oxide having a molecular weight higher than 200,000 g/mol. The polyethylene oxide may be present as a single compound or a mixture of at least two polyethylene oxides having a molecular weight higher than 200,000 g/mol.

As used herein, ‘polyethylene oxide’ refers to polyethylene oxides (PEO) or high molecular weight polyethylene glycols (PEGs). As used herein, ‘high molecular weight polyethylene glycol’ means a linear homopolymer derived from ethylene oxide and having a molecular weight of at least 200,000 g/mol.

Preferably, the polyethylene oxide has a molecular weight of 300,000 g/mol to 4,000,000 g/mol, more preferably 500,000 g/mol to 3,000,000 g/mol, even more preferably 1,000,000 to 2,000,000 g/mol.

Suitable examples include, but are not limited to, polyethylene oxides commercially available with trade names WSR N-10, WSR N-80, WSR N-750, WSR 205, WSR 1105, WSR N-12K, WSR N-60K, WSR-301, WSR-303, WSR-308, all from The Dow Chemical

Company; polyethylene oxide (PEO) from MSE, Beantown chemicals or Acros Organics; PEO 100K from Polysciences; PEO-1, PEO2, PEO-3, PEO-4, PEO-8, PEO15, PEO-18, PEO-57, PEO-29 from Sumitomo Seika Chemicals Ltd.; or ALKOX polyethylene Glycol from Meisei Chemical Works. If the cleaning polymer is present, then it is preferably present in an amount of 0.001 to 0.2 wt% based on the total weight of the composition. More preferably, the cleaning polymer is present in an amount of 0.01 to 0.15, even more preferably 0.02 to 0.1 wt%.

Inorganic salts

The composition comprises 0.05 to 5% by weight of an inorganic salt selected from the group consisting of sodium chloride, magnesium sulfate, sodium sulfate and combinations thereof. Preferably the inorganic salt is sodium sulfate. Inorganic salts advantageously control the viscosity of the detergent compositions.

Preferably, the composition comprises 0.2 to 4%, more preferably 0.3% to 3%, even more preferably 0.5 to 2.0 % by weight of an inorganic salt.

Preferably the pH of the composition of the present invention is between 3.0 and 8.0 measured at 20° Celsius. Preferably, the pH is between 3.5 and 7.5, more preferably between 4.2 and 4.8.

The composition according to the invention may contain other ingredients which aid in the cleaning or sensory performance. Compositions according to the invention can also contain, in addition to the ingredients already mentioned, various other optional ingredients such as thickeners, colorants, preservatives, fatty acids, anti-microbial agents, perfumes, pH adjusters, sequestrants, alkalinity agents and hydrotropes.

Organic solvents

Preferred compositions do not contain large amounts of organic solvents, usually added to boost cleaning performance, that is from 0 to 1 wt% organic solvent. Preferably the composition is free of organic solvents.

Silicones

Compositions of the present invention preferably comprise only limited amounts of silicones as these may not provide the required user characteristics for cleaning compositions of the present invention. Silicones may for example leave a ‘slippery’ feel to hard surfaces like plates and cutlery. Therefore, the composition of the present invention comprises from 0 to 1 wt%, more preferably from 0 to 0.5 wt% and still more preferably from 0 to 0.1 wt% silicones. Still more preferably the composition is free of silicones. Product format

The composition may be used neat or diluted. For hard surface cleaning or more specifically for dishwashing purposes, the composition is typically applied neat directly to the surface or on an implement like for example a sponge or cloth. When applied in a diluted form, the composition is preferably diluted with water in a ratio of between 1 :1 to 1:100 and more preferably in a ratio of between 1 : 1 to 1 : 10.

The composition may be packaged in the form of any commercially available bottle or pouch for storing the liquid.

The bottle or pouch containing the liquid can be of different sizes and shapes to accommodate different volumes of the liquid; preferably between 0.25 and 2 L, more preferably between 0.25 and 1.5 L or even between 0.25 and 1 L. The bottle or pouch is preferably provided with a dispenser, which enables the consumer an easier mode of dispersion of the liquid. Spray or pump-dispensers may also be used.

Process

The invention also relates to a method of cleaning a hard surface comprising the steps of: a. contacting the hard surface, optionally in diluted form, with the liquid detergent composition according to the present invention, and b. removing the detergent composition from the hard surface, optionally by rinsing with water.

Preferably, the method of cleaning is a manual cleaning, more preferably hand dishwashing.

‘Hard surface’, as used herein, typically means utensils or kitchenware, kitchen worktops, kitchen floors, sinks and kitchen counter tops, floors and bathrooms.

In any of the processes above, the composition of the invention is applied onto a hard surface in neat or diluted form. The composition may be applied by any known ways such as by using a cleaning implement, such as scrub, sponge paper, cloth, wipes or any other direct or indirect application. The applied composition may be cleaned using a cleaning implement such as a scrub, sponge, paper, cloth or wipes with or without water, or rinsed off with water, optionally running water. In a further aspect, the invention relates to the use of a surfactant system to improve foaming behaviour in an aqueous liquid detergent composition comprising rhamnolipid surfactant wherein the surfactant system comprises: a primary surfactant mix comprising alkyl ether sulfate surfactant and alkyl sulfate surfactant; and an amphoteric surfactant selected from betaines, glucamides and sultaines; wherein the weight ratio of (alkyl ether sulfate surfactant + alkyl sulfate surfactant) I amphoteric surfactant is from 4.5 to 1; and the percentage of alkyl sulfate surfactant calculated on total amount of alkyl sulphate and alkyl ether sulfate is from 45 to 95.

The invention will now be illustrated by means of the following non-limiting examples.

Examples

Foam generation protocol

To determine the volume of: foam created in the absence of soil, referred to as ‘flash foam’; foam after the addition of soil, i.e. ability of the foam to withstand soil addition, referred to as ‘yield foam’; foam in the presence of soil, referred to as ‘build foam’; the following protocol is followed: in a 500 ml glass cylinder, 3 grams of dishwashing product is diluted in 200 ml deionized water; the cylinder is closed with a stopper and placed into an automatic rotating instrument at 10 rpm such that the cylinder is turned upside down rotationally; the test is done in triplicate; the volume of flash foam is recorded after 20 rotations by measuring the volume of foam above the waterline; to determine the volume of yield foam, 5 grams of a fat-flour soil is added to each of the cylinders and rotated for 10 rotations after which the foam volume is measured; - to determine the volume of build foam the cylinders are then rotated for another 40 rotations after which the foam volume is measured.

Example 1 Aqueous liquid detergent compositions were prepared according to Table 1 - Sample 1 and comparatives A to D. For each of the prepared compositions flash foam, yield foam and build foam was measured according to the protocol described above. The foam data can be found in Table 2. TABLE 1 (wt% calculated in total product, water to 100)

TABLE 2

Claims

1. An aqueous liquid detergent composition comprising: from 3 to 30 wt% of a surfactant system comprising:

(iii) from 0.25 to 5 wt% rhamnolipid biosurfactant; from 0.05 to 5 wt% of an inorganic salt selected from sodium chloride, magnesium sulphate and sodium sulphate; wherein the weight ratio of (alkyl ether sulfate surfactant + alkyl sulfate surfactant) I amphoteric surfactant is from 4.5 to 1; and the percentage of alkyl sulfate surfactant calculated on total amount of alkyl sulphate and alkyl ether sulfate is from 45 to 95.

2. The composition according to claim 1 wherein the weight ratio of (alkyl ether sulfate surfactant + alkyl sulfate surfactant) I amphoteric surfactant is from 4 to 1, preferably from 3.5 to 1.5.

3. The composition according to claim 1 or 2 wherein the percentage of alkyl sulfate surfactant calculated on total amount of alkyl sulphate and alkyl ether sulfate is from 50 to 80, preferably 55 to 70.

4. The composition according to any one of claims 1 to 3 wherein the primary surfactant mix has a weight average degree of branching of less than 30%, preferably less than 20% and more preferably less than 10%.

5. The composition according to any one of claims 1 to 4 comprising from 0.5 to 2 wt% rhamnolipid biosurfactant.

6. The composition according to any one of claims 1 to 5 comprising from 3 to 20 wt% of the surfactant system, preferably from 4 to 15 wt% and more preferably from 5 to 10 wt%.

7. The composition according to any one of claims 1 to 6 wherein the alkyl ether sulfate surfactant comprises alkyl ether sulfate having 1 to 2 ethylene oxide units per molecule, preferably lauryl ether sulfate having 1 to 2 ethylene oxide units per molecule.

8. The composition according to any one of claims 1 to 7 wherein the amphoteric surfactant comprises betaine selected from alkyl betaine, alkyl amido betaine, alkyl amidopropyl betaine, alkyl sulphobetaine, alkyl phosphobetaine and combinations thereof.

9. The composition according to any one of claims 1 to 8 wherein the betaine is cocam idopropyl betaine.

10. The composition according to any one of claims 1 to 9 wherein the composition has a viscosity in the range of 500 to 3500 cps at 21 sec¹ measured on a Haake Viscometer with a cup and bob geometry, equipped with a MV cup and a MV2 bob at a controlled temperature of 25° Celsius, preferably 1500 to 2500 and more preferably 1700 to 2300.

11. The composition according to any one of claims 1 to 10 wherein the composition comprises from 0 to 1 wt% silicone.

12. The composition according to any one of claims 1 to 11 wherein the surfactant system comprises alkylbenzene sulphonate or derivatives thereof in an amount of up to 25 wt% of the total amount of anionic surfactant and preferably is free of any sulphonate.

13. A method of cleaning a hard surface comprising the steps: contacting the hard surface, optionally in diluted form, with the liquid detergent composition according to any one of claims 1 to 12, and removing the detergent composition from the hard surface, optionally by rinsing with water.

14. The method of cleaning according to claim 13, wherein the hard surface is dishware.

15. Use of a surfactant system to improve foaming behaviour in an aqueous liquid detergent composition comprising rhamnolipid surfactant wherein the surfactant system comprises: a primary surfactant mix comprising alkyl ether sulfate surfactant and alkyl sulfate surfactant; and an amphoteric surfactant selected from betaines, glucamides and sultaines; wherein the weight ratio of (alkyl ether sulfate surfactant + alkyl sulfate surfactant) I amphoteric surfactant is from 4.5 to 1; and the percentage of alkyl sulfate surfactant calculated on total amount of alkyl sulphate and alkyl ether sulfate is from 45 to 95.