WO2010067054A1

WO2010067054A1 - Drying aid composition

Info

Publication number: WO2010067054A1
Application number: PCT/GB2009/002832
Authority: WO
Inventors: Mauro Davanzo; Georg Ferner; Emanuele Rossetto
Original assignee: Reckitt Benckiser N. V.; Reckitt Benckiser (Uk) Limited
Priority date: 2008-12-08
Filing date: 2009-12-07
Publication date: 2010-06-17
Also published as: GB0822323D0

Abstract

The invention provides a liquid composition comprising a non-ionic surfactant mixture comprising i) a non-ionic surfactant having a cloud point of 50° C or above, and ii) a non-ionic surfactant having a cloud point of below 50° C, wherein the weight ratio of a) to b) is in the range of from 2.25:1 to 1:1. The compositions provide good drying properties on treated articles and are preferably dishwashing composition, most especially rinse aid compositions.

Description

DRYING AID COMPOSITION

Technical field

The present invention relates to liquid compositions which exhibit good drying properties of hard surfaces such as items to be treated in dishwashing applications and especially in automatic dishwashers. In particular the present invention relates to such compositions comprising a mixture of a) an alkoxylkated non-ionic surfactant comprising a single alkoxylate type and b) an alkoxylkated non-ionic surfactant comprising at least two alkoxylate types.

Background and Prior Art

As a usual part of a cleaning operation, e.g. for kitchenware or other hard surfaces such as walls, windows, kitchen surfaces etc, an aqueous composition or water is applied to the cleansed articles to remove the detergent composition employed during a previous cleansing step. This is generally referred to as a rinse step. However, this has the disadvantage of re-wetting the items and in many cleaning operations it is desired that the cleansed items dry as quickly as possible. This is true in both manual and automatic dishwashing operations where the time taken for cleaned items, such as kitchenware, to dry is very noticeable. This is also true cleaning operations of hard surfaces in domestic and commercial situations. In automatic dishwashing, there is a desire for the items to be dry when the dishwashing machine is opened and if this is not achieved it often leads to dissatisfaction with the cleaning operation. With manual dishwashing it is desired that the cleansed items dry as quickly as possible so that wet items do not need to be left for prolonged periods to dry in the open air.

Therefore, there is a need in the art to provide compositions exhibiting good drying properties on hard surfaces after they have been rinsed, which compositions can be used in the rinsing of hard surfaces such as in dishwashing operations of items e.g. kitchenware.

Furthermore the formulator of compositions for use in dishwashing applications is always under pressure to provide as many different benefits for a given composition. Accordingly, such a formulator is always seeking to minimise the amount of any one type of ingredient present in a composition.

Therefore, there is also a need in the art to provide compositions exhibiting good drying properties but in which the amount of ingredients providing that drying effect is minimised.

It is an object of the present invention to address one or more of the above-mentioned problems.

In particular, it is an object of the present invention to provide compositions that provide good drying of cleansed articles following a manual or automatic dishwashing operation. It is a further object of the present invention to provide compositions that provide such good drying of cleansed articles and which contain relatively low concentration of ingredients providing this effect. It is still a further object to provide such detergent compositions which exhibit good stability and drying properties for such cleansed articles.

Surprisingly it has now been found according to the present invention that certain mixtures of certain non- ionic surfactants provide good drying properties and most especially in dishwashing applications.

It is known in the art to include non-ionic surfactants in compositions to be used in dishwashing applications for both their wetting properties, which in turn enhances drying properties, and also their low-foaming characteristics and many dishwashing detergents and dishwashing rinse aids currently available^' in the market contain such surfactants. Also such types of compositions are known for example from EP-A-1, 757, 676, US 6,034,044, US 5,877,134 and GB 2 327 948.

Statement of invention

It has been found that one of more of the above problems can be addressed by a composition according to the present invention.

Accordingly the present invention provides a liquid composition comprising a non-ionic surfactant mixture comprising; a) a non-ionic surfactant having a cloud point of 50⁰C or above, and b) a non-ionic surfactant having a cloud point of below

5O⁰C, wherein the weight ratio of a) to b) is in the range of from 2.25: 1 to 1:1.

According to a second embodiment the present invention provides the use of a dishwashing composition of the invention in a dishwashing operation.

According to a third embodiment the present invention provides the use of a dishwashing composition of the invention to provide improved drying of cleansed articles.

The particular non-ionic surfactant mixture used in the compositions of the invention show very good drying properties of treated articles when used in a dishwashing operation, especially an automatic dishwashing operation. In particular the ratio of the two types of non-ionic surfactants used in the present invention allows for reduced total amounts of these surfactants to be used compared to compositions which contain these surfactants in ratios outside that of the present invention.

Surprisingly, it has been found that compositions according to the invention comprising the specified non- ionic surfactants in the specified amounts provide good drying properties on articles treated in a dishwashing operation. This has been found to be especially advantageous for dishwashing detergent or rinse aid compositions including both manual and automatic dishwashing detergent compositions. Unless stated otherwise, all amounts herein are given as the percentage by weight of active ingredient based upon the weight of the total composition.

The term "automatic dishwashing detergent composition" as used herein means a dishwashing detergent composition to be used in dishwashing machine.

Detailed description

The present invention will now be described in further detail.

It is especially preferred according to the present invention that the compositions are hard surface cleaners and in particular dishwashing detergents, most especially automatic dishwashing compositions.

The liquid detergent compositions according to the invention may be either manual or automatic dishwashing compositions. Especially preferred types of detergent composition according to the present invention are automatic dishwashing compositions. The dishwashing compositions according to the present invention may be either dishwashing detergent compositions which are intended for the cleansing of soiled dishes, or, rinse aid compositions which are designed for use in the rinse cycle of an automatic dishwashing machine. The composition may be acidic, especially if it is a rinse aid composition (measured as a 10%wt dilution in distilled water at 20°c) . a) composition format

The dishwashing compositions of the present invention are in liquid form. For the avoidance of doubt, the term "liquid" as used herein includes pastes and gels. The liquid composition may be encased in a water soluble wrapping, for, example of PVOH or a cellulosic material.

According to one embodiment of the present invention the composition is in the form of a unit dose product, i.e. a form which is designed to be used as a single portion of detergent composition in a washing operation such as a water soluble or water dispersible pouch. Of course, one or more of such single portions may be used in a cleaning operation.

The compositions of the invention may be made by any conventional method. Suitable methods are well known in the art and do not need to be described in further detail here. For example, the liquid compositions may be produced by any suitable method such as simply mixing together the ingredients.

b) The non-ionic surfactant mixture

The non-ionic surfactant mixture included in the liquid compositions according to the present invention is described hereinbelow. Compositions comprising this mixture have been found to exhibit good drying properties especially on items treated in a dishwashing operation.

The liquid compositions comprise a non-ionic surfactant mixture comprising; a) a non-ionic surfactant having a cloud point of 50⁰C or above, and b) a non-ionic surfactant having a cloud point of below 5O⁰C, wherein the weight ratio of a) to b) is in the range of from 2.25:1 to 1:1.

It is preferred that the cloud point of non-ionic surfactant a) is in the range of from 55⁰C to 85°C, more preferably 60⁰C to 80°C. It is preferred that the cloud point of non-ionic surfactant b) is in the range of from 1O⁰C to 45°C, more preferably 15°C to 35⁰C.

According to the present invention it is most preferred that the nonionic surfactant a) has a cloud point in the range of from 6O⁰C to 80⁰C and the nonionic surfactant b) has a cloud point in the range of from of from 15°C to 35⁰C. Particularly good results have been achieved according to the invention by compositions comprising a non-ionic surfactant mixture, wherein the non-ionic surfactant a) is an alkoxylkated non-ionic surfactant having a single alkoxylate type, and the non-ionic surfactant b) is an alkoxylkated non-ionic surfactant having at least two alkoxylate types.

The alkoxylated non-ionic surfactants of type a) may be prepared by the reaction of a monohydroxy alkanol or alkylphenol with 6 to 20 carbon atoms, preferably 8 to 18 carbon atoms, most preferably 10 to 16 carbon atoms, such as 12 to 15 carbon atoms. It is preferred that the type of alkoxylate in type a) surfactant is ethoxylate, butoxylate or propoxylate with ethoxylate being especially preferred. Preferably the surfactants of type a) have 3 to 15 moles particularly preferred 4 to 10 moles, and still more preferred 5 to 8 moles of alkylene oxide, particularly ethylene oxide, per mole of alcohol or alkylphenol. A particularly preferred surfactant of type a) is C10-C15 with 5-10 EO. The non-ionic surfactants of type a) may be prepared from either branched or linear chain fatty alcohols of the above types.

The alkoxylated non-ionic surfactants of type b) may be prepared by the reaction of a monohydroxy alkanol or alkylphenol with 6 to 25 carbon atoms, preferably 8 to 20 carbon atoms, most preferably 10 to 18 carbon atoms e.g. C13-C15. It is preferred that the surfactant of type b) has 2 to 15 moles in total of alkylene oxide per mole of surfactant. It is preferred that the type of alkoxylates in type b) surfactant is a mixture of at least two of ethoxylate, butoxylate and/or propoxylate, with a mixture of ethoxylate and butoxylate being especially preferred. Preferably the surfactants of type b) have a 2 to 10 moles, especially 3 to 8 moles, and still more preferred 4 to 7 moles ethylene oxide per mole of alcohol or alkylphenol and 0.5 to 10 moles, more preferably 1 to 5 moles, such as 2 to 4 moles of butylene oxide or propylene oxide per mole of alcohol or alkylphenol. A mixture of butylene oxide or propylene oxide is also possible. A particularly preferred surfactant of type b) is C10-C15 with 2-7 EO and 1-5 BO, more preferably CIS- CIS with 3-7 EO and 1-4 BO. The non-ionic surfactants of type b) may be prepared from either branched or linear chain fatty alcohols of the above types.

The surfactant of type b) is typically more hydrophobic than the type a) surfactant and the amounts and types of the two surfactants in the claimed mixture are preferably selected such that the foaming characteristics of the composition are controlled to within the desired range. For dishwashing applications it is usual to desire low- foaming characteristics.

Surfactants of type b) may also include surfactants which are ethoxylated and butoxylated mono-hydroxy alkanols or alkylphenols, which additionally comprises polyoxyethylene-polyoxypropylene block copolymer units. The alcohol or alkylphenol portion of such surfactants constitutes more than 30%, preferably more than 50%, more preferably more than 70% by weight of the overall molecular weight of the non-ionic surfactant.

It is especially preferred according to the present invention that the surfactant of type a) is an ethoxylated non-ionic surfactant and the surfactant of type b) is a mixed ethoxylated-butoxylated non-ionic surfactant.

The weight ratio of non-ionic surfactant type a:b is preferably in the range 2.2:1 to 1:1, more preferably 2:1 to 1:1, most preferably 2.0:1 to 1:1.

The amount of non-ionic surfactant type a) is preferably in the range of from 0.5 to 40%wt, more preferably 2 to 20% wt, most preferably 5 to 15%wt. The amount of non- ionic surfactant type b) is preferably in the range of from 0.5 to 40%wt, more preferably 1 to 20%wt, most preferably 2 to 10%wt. Typically the compositions according to the invention comprise a total concentration of surfactant types a) and b) in the range of from 1 to 25%wt, preferably 2 to 20%wt, most preferably 5 to 15%wt.

c) optional ingredients The compositions of the invention may be aqueous based. For such compositions the amount of water present in the compositions is typically in the range of from 5 to 90%wt, preferably 20 to 85% wt, such as 35 to 80%wt.

Polymers intended to improve the cleaning performance of the detergent compositions may also be included therein and indeed these are preferred according to the present invention. For example sulphonated polymers may be used and these are particularly preferred. Preferred examples

1 2 3 4 include copolymers of CH₂=CR -CR R -O-C₄H3R -SO₃X wherein

1 2 3 4 R , R , R , R are independently 1 to 6 carbon alkyl or hydrogen, and X is hydrogen or alkali with any suitable other monomer units including modified acrylic, fumaric, maleic, itaconic, aconitic, mesaconic, citraconic and methylenemalonic acid or their salts, maleic anhydride, acrylamide, alkylene, vinylmethyl ether, styrene and any mixtures thereof. Other suitable sulfonated monomers for incorporation in sulfonated (co) polymers are 2- acrylamido-2-methyl-l-propanesulfonic acid, 2- methacrylamido-2-methyl-l-propanesulfonic acid, 3- methacrylamido-2-hydroxy-propanesulfonic acid, allysulfonic acid, methallysulfonic acid, 2-hydroxy~3- (2- propenyloxy) propanesulfonic acid, 2-methyl~2-propenen-l- sulfonic acid, styrenesulfonic acid, vinylsulfonic acid, 3-sulfopropyl acrylate, 3-sulfopropylmethacrylate, sulfomethylacrylamide, sulfomethylmethacrylamide and water soluble salts thereof. Suitable sulfonated polymers are also described in US 5308532 and in WO 2005/090541.

When a sulfonated polymer is present, it is preferably present in the composition in an amount of at least 0.1 wt%, preferably at least 0.5 wt%, more preferably at least 1 wt%, and most preferably at least 3 wt%, up to 10 wt%, preferably up to 7 wt%, more preferably up to 6 wt%, and most preferably up to 5 wt% .

It is known to include a source of multivalent ions in cleaning compositions, and in particular in automatic dishwashing compositions, for technical and/or performance reasons. Such optional ingredients are especially preferred according to the present invention. For example, multivalent ions and especially zinc and/or manganese ions have been included for their ability to inhibit corrosion on metal and/or glass. Bismuth ions may also have benefits when included in such compositions.

For example, organic and inorganic redox-active substances which are known as suitable for use as silver/copper corrosion inhibitors are mentioned in WO 94/26860 and WO 94/26859. Suitable inorganic redox- active substances are, for example, metal salts and/or metal complexes chosen from the group consisting of zinc, manganese, titanium, zirconium, hafnium, vanadium, cobalt and cerium salts and/or complexes, the metals being in one of the oxidation states II, III, IV, V or VI. Particularly suitable metal salts and/or metal complexes are chosen from the group consisting of MnSO₄, Mn(II) citrate, Mn(II) stearate, Mn(II) acetylacetonate, Mn(II) [1-hydroxyethane-l, 1-diphosphonate] , V₂O₅, V₂O₄, VO₂, TiOSO₄, K₂TiF₆, K₂ZrF₆, CoSO₄, Co (NO₃) 2 and Ce(NO₃J₃. Zinc salts are specially preferred corrosion inhibitors.

Therefore, an especially preferred optional ingredient according to the present invention is a source of multivalent ions such as those mentioned in the immediately preceding paragraph and in particular zinc, bismuth and/or manganese ions. In particular a source of zinc ions is preferred. Any suitable source of multivalent ions may be used, with the source preferably being chosen from sulphates, carbonates, acetates, gluconates and metal-protein compounds and those mentioned in the immediately preceding paragraph.

Any conventional amount of multivalent ions/multivalent ions source may be included in the compositions of the invention. However, it is preferred that the multivalent ions are present in an amount of from 0.01%wt to 5%wt, preferably 0. l%wt to 3%wt, such as 0.5%wt to 2.5%wt. The amount of multivalent ion source in the compositions of the invention will thus be correspondingly higher.

The composition of the invention may also comprise a silver/copper corrosion inhibitor in conventional amounts. This term encompasses agents that are intended to prevent or reduce the tarnishing of non-ferrous metals, in particular of silver and copper. Preferred silver/copper corrosion inhibitors are benzotriazole or bis-benzotriazole and substituted derivatives thereof.

Other suitable agents are organic and/or inorganic redox- active substances and paraffin oil. Benzotriazole derivatives are those compounds in which the available substitution sites on the aromatic ring are partially or completely substituted. Suitable substituents are linear or branch-chain Ci-20 alkyl groups and hydroxyl, thio, phenyl or halogen such as fluorine, chlorine, bromine and iodine. A preferred substituted benzotriazole is tolyltriazole.

The composition according to the invention may comprise one or more foam control agents. Suitable foam control agents for this purpose are all those conventionally used in this field, such as, for example, silicones and paraffin oil. The foam control agents are preferably present in the composition in amounts of 5% by weight or less of the total weight of the composition.

The detergent compositions of the invention may also comprise minor, conventional amounts of perfumes, hydrotropes, complexation/sequestering agents, corrosion inhibitors/anti-oxidants, preservatives and/or colourants. Such ingredients are typically present in amounts of up to 5%wt. If the compositions of the invention are dishwashing detergent compositions, they preferably further comprise a bleaching compound. If the compositions of the invention are rinse aid compositions they are preferably substantially bleach free.

Any type of bleaching compound conventionally used in detergent compositions may be used according to the present invention in the dishwashing detergent compositions. Preferably the bleaching compound is selected from inorganic peroxides or organic peracids, derivatives thereof (including their salts) and mixtures thereof. Especially preferred inorganic peroxides are percarbonates, perborates and persulphates with their sodium and potassium salts being most preferred. Sodium percarbonate and sodium perborate are most preferred, especially sodium percarbonate.

Organic peracids include all organic peracids traditionally used as bleaches, including, for example, perbenzoic acid and peroxycarboxylic acids such as mono- or diperoxyphthalic acid, 2-octyldiperoxysuccinic acid, diperoxydodecanedicarboxylic acid, diperoxy-azelaic acid and imidoperoxycarboxylic acid and, optionally, the salts thereof. Especially preferred is phthalimidoperhexanoic acid (PAPj .

Desirably the bleaching compound is present in the detergent compositions in an amount of from 1 to 60wt%, especially 5 to 55wt%, most preferably 10 to 50%wt, such as 10 to 20%wt. If the composition is a dishwashing detergent composition it may also comprise conventional amounts of detergent builders which may be either phosphorous based or non- phosphorous based, or even a combination of both types. Suitable builders are well known in the art. Rinse aid compositions do not typically comprise detergent builders or if such ingredients are present it is typically in minor amounts.

If phosphorous builders are to be used in the detergent compositions then it is preferred that mono-phosphates, di-phosphates, tri-polyphosphates or oligomeric- poylphosphates are used. The alkali metal salts of these compounds are preferred, in particular the sodium salts. An especially preferred builder is sodium tripolyphosphate (STPP) .

The non-phosphorous based builder may be organic molecules with carboxylic group (s), amino acid based compound or a succinate based compound. The term

^succinate based compound' and ^succinic acid based compound' are used interchangeably herein.

Builder compounds which are organic molecules containing carboxylic groups include citric acid, fumaric acid, tartaric acid, maleic acid, lactic acid and salts thereof. In particular the alkali or alkaline earth metal salts of these organic compounds may be used, and especially the sodium salts. An especially preferred builder is sodium citrate. Preferred examples of amino acid based compounds according to the invention are MGDA (methyl-glycine- diacetic acid, and salts and derivatives thereof) and GLDA (glutamic-N, N-diacetic acid and salts and derivatives thereof) . GLDA (salts and derivatives thereof) is especially preferred according to the invention, with the tetrasodium salt thereof being especially preferred. Other suitable builders are described in US 6, 426, 229 which is incorporated by reference herein. Particular suitable builders include; for example, aspartic acid-N-monoacetic acid (ASMA) , aspartic acid-N,N-diacetic acid (ASDA) , aspartic acid-N- monopropionic acid (ASMP), iminodisuccinic acid (IDA), N- (2-sulfomethyl) aspartic acid (SMAS), N- (2- sulfoethyl) aspartic acid (SEAS), N- (2- sulfomethyl) glutamic acid (SMGL), N- (2- sulfoethyl) glutamic acid (SEGL), N- methyliminodiacetic acid (MIDA), α- alanine-N,N-diacetic acid (α-ALDA) , β- alanine-N,N-diacetic acid (β-ALDA), serine-N, N-diacetic acid (SEDA), isoserine-N, N-diacetic acid (ISDA), phenylalanine-N, N-diacetic acid (PHDA), anthranilic acid- N, N- diacetic acid (ANDA), sulfanilic acid-N, N-diacetic acid (SLDA), taurine~N, N-diacetic acid (TUDA) and sulfomethyl-N, N-diacetic acid (SMDA) and alkali metal salts or ammonium salts thereof.

Further preferred succinate compounds are described in US-A-5, 977, 053 and have the formula;

in which R, R , independently of one another, denote H or

2 3 4 5 OH, R , R , R , R , independently of one another, denote a cation, hydrogen, alkali metal ions and ammonium ions,

(^■> 7 R 9 ammonium ions having the general formula R R R R N+ and f. π Q o

R , R , R , R , independently of one another, denoting hydrogen, alkyl radicals having 1 to 12 C atoms or hydroxyl-substituted alkyl radicals having 2 to 3 C atoms. A preferred example is tetrasodium imminosuccinate .

Preferably the total amount of builder present in the detergent compositions of the invention is at least 5 wt%, preferably at least 10 wt%, more preferably at least 20 wt%, and most preferably at least 25 wt%, preferably in an amount of up to 70wt%, preferably up to 65wt%, more preferably up to 60wt%, and most preferably up to 35 wt% . The actual amount used will depend upon the nature of the builder used.

The detergent compositions of the invention may further comprise a secondary builder (or cobuilder) . Preferred secondary builders include homopolymers and copolymers of polycarboxylic acids and their partially or completely neutralized salts, monomeric polycarboxylic acids and hydroxycarboxylic acids and their salts, phosphates and phosphonates, and mixtures of such substances. Preferred salts of the abovementioned compounds are the ammonium and/or alkali metal salts, i.e. the lithium, sodium, and potassium salts, and particularly preferred salts is the sodium salts. Secondary builders which are organic are preferred. Suitable polycarboxylic acids are acyclic, alicyclic, heterocyclic and aromatic carboxylic acids, in which case they contain at least two carboxyl groups which are in each case separated from one another by, preferably, no more than two carbon atoms.

Polycarboxylates which comprise two carboxyl groups include, for example, water-soluble salts of, malonic acid, (ethylenedioxy) diacetic acid, maleic acid, diglycolic acid, tartaric acid, tartronic acid and fumaric acid. Polycarboxylates which contain three carboxyl groups include, for example, water-soluble citrate. Correspondingly, a suitable hydroxycarboxylic acid is, for example, citric acid.

Another suitable polycarboxylic acid is the homopolymer of acrylic acid. Other suitable builders are disclosed in WO 95/01416, to the contents of which express reference is hereby made.

The compositions of the invention may contain additional surface active agents to those forming part of the surfactant mixture described above and which forms an essential part of the compositions of the invention. The additional surface active agents may be anionic, cationic, amphoteric or zwitterionic surface active agents or mixtures thereof. Any such conventional surfactant may be used in addition to the nonionic surfactant mixture of the invention. Many such surfactants are described in Kirk Othmer's Encyclopedia of Chemical Technology, 3rd Ed., Vol. 22, pp. 360-379, "Surfactants and Detersive Systems", incorporated by reference herein.

The composition of the invention may comprise one or more enzymes, especially when they are detergent compositions. It is preferred that the enzyme is selected from protease, lipase, amylase, cellulase and peroxidase enzymes. Such enzymes are commercially available and sold, for example, under the registered trade marks

RTM _,_ . RTM _π „ . RTM . Esperase , Alcalase and Savmase by Nova

RTM

Industries A/S and Maxatase by International

Biosynthetics, Inc. It is most preferred that protease enzymes are included in the compositions according to the invention.

Desirably enzyme (s) is/are present in the composition in an amount of from 0.01 to 3wt%, especially 0.1 to 2.5 wt%, such as 0.2 to 2 wt% .

The compositions according to the invention may comprise a buffering system to maintain the pH of the composition at a desired pH on dissolution and this may comprise a source of acidity or a source of alkalinity as necessary. If the composition is a detergent composition a source of alkalinity is typically included which may be any suitable compound which is basic; for example any salt of a strong base and a weak acid such as soda. However additional acids or bases may be present. In the case of alkaline compositions silicates, phosphates or hydrogen phosphates may suitably be used. Preferred silicates are sodium silicates such as sodium disilicate, sodium metasilicate and crystalline phyllosilicates . If the composition of the invention is a rinse aid then a source of acidity is preferably included and this may suitably be any components which are acidic; for example polycarboxylic acids. Citric acid is especially preferred and salts of these acids may also be used.

The composition is described with reference to the following non-limiting Examples. Further examples within the scope of the invention will be apparent to the person skilled in the art.

Examples

Example 1

The following liquid rinse aid composition was prepared by mixing the ingredients together. The composition was found to have very good drying properties when used in an automatic dishwashing process.

Claims

1. A liquid composition comprising a non-ionic surfactant mixture comprising; a) a non-ionic surfactant having a cloud point of 50 C or above, and b) a non-ionic surfactant having a cloud point of below 50⁰C, wherein the weight ratio of a) to b) is in the range of from 2.25:1 to 1:1.

2. A liquid composition according to Claim 1, wherein the cloud point of non-ionic surfactant a) is in the range of from 60⁰C to 80⁰C.

3. A liquid composition according to either one of claims 1 or 2, wherein the cloud point of non-ionic surfactant b) is in the range of from 15⁰C to 35°C.

4. A liquid composition according to any one of claims 1 to 3, wherein the nonionic surfactant a) has a cloud point in the range of from 60⁰C to 80⁰C, and the nonionic surfactant b) has a cloud point in the range of from of from 15⁰C to 35⁰C.

5. A liquid composition according to any one of the preceding claims, comprising a non-ionic surfactant mixture, wherein the non-ionic surfactant a) is an alkoxylkated non-ionic surfactant having a single alkoxylate type, and the non-ionic surfactant b) is an alkoxylkated non-ionic surfactant having at least two alkoxylate types.

6. A liquid composition according to any one of the preceding claims, wherein the composition is acidic.

7. A liquid composition according to any one of the preceding claims, wherein the composition is a rinse aid.

8. A liquid composition according to any one of the preceding claims, wherein the surfactant of type a) has 3 to 15 moles of alkylene oxide per mole of surfactant.

9. A liquid composition according to any one of the preceding claims, wherein the non-ionic surfactant of type a) is an ethoxylated non-ionic surfactant.

10. A liquid composition according to any one of the preceding claims, wherein the surfactant of type b) has 2 to 15 moles of alkylene oxide per mole of surfactant.

11. A liquid composition according to any one of the preceding claims, wherein the surfactant of type b) is a mixed ethoxylated-butoxylated non-ionic surfactant.

12. A liquid composition according to any one of the preceding claims, wherein the surfactant of type a) is an ethoxylated non-ionic surfactant and the surfactant of type b) is a mixed ethoxylated-butoxylated non- ionic surfactant.

13. A liquid composition according to any one of the preceding claims, wherein the weight ratio of a) to b) is in the range of from 2.2:1 to 1:1.

14. A liquid composition according to any one of the preceding claims, wherein composition comprises surfactant a) in an amount of from 0.5-40%wt.

15. A composition according to any one of the preceding claims, wherein composition comprises surfactant b) in an amount of from 0.5-40%wt.

16. The use of a dishwashing composition as defined in any one of the preceding claims in a dishwashing operation.

17. The use of a dishwashing composition according to any one of the preceding claims to provide improved drying of cleansed articles.