Field of the Invention

The present invention relates to liquid laundry detergents comprising ethoxylated polyethyleneimine (EPEI) for an improved product viscosity profile without impairing cleaning performance.

Background and Prior Art

There is a continuing need to improve the cleaning performance of laundry liquids as consumers move to lower wash temperatures and seek products with improved environmental credentials. One route to improving the environmental profile of liquid laundry detergents is the addition of highly weight efficient or multi-functional materials to replace traditional materials such as surfactants resulting in a lower overall chemicals usage.

One such ingredient is ethoxylated polyethyleneimine (EPEI) which is known to improve particulate soil removal from fabrics. However, the inclusion of EPEI may reduce the viscosity of the resulting liquid, leading to reduced consumer acceptability and hence the need to include additional viscosity-boosting technology.

The present invention addresses this problem.

Summary of the Invention

The present invention provides a liquid laundry detergent composition comprising ethoxylated polyethyleneimine (EPEI) for an improved product viscosity profile without impairing cleaning performance; the detergent composition comprising: a) from 6 to 50% (by weight based on the total weight of the composition) of one or more detersive surfactants selected from non-soap anionic surfactants, nonionic surfactants and mixtures thereof, and

b) from 0.5 to 10% of an ethoxylated polyethyleneimine (EPEI) having a

polyethyleneimine backbone made up of repeating -[(CH CH )N]- subunits; and one or more polyoxyethylene side chains which are bonded to internal and/or terminal nitrogen atoms in the polyethyleneimine backbone;

in which the polyethyleneimine backbone is derived from a polyethyleneimine starting material which is ethoxylated to produce EPEI;

in which the polyethyleneimine starting material has an average molecular weight (M _w ) ranging from 1800 to 5000 g/mol (prior to ethoxylation), and the polyoxyethylene side chains have an average of from 25 to 40 ethoxy units per side chain bonded to the polyethyleneimine backbone.

Detailed Description and Preferred Embodiments

Ethoxylated polyethyleneimine (EPEI)

The ethoxylated polyethyleneimine (EPEI) for use in the invention includes inter alia a polyethyleneimine backbone made up of repeating -[(CH CH )N]- subunits. The backbone derives from a polyethyleneimine starting material (as defined above) which is ethoxylated to produce EPEI.

More preferably the polyethyleneimine starting material (prior to ethoxylation) has an average molecular weight (M _w ) ranging from 1800 to 2400 g/mol, and most preferably from 1800 to 2200 g/mol, such as from 1900 to 2100 g/mol, determined by gel permeation chromatography (GPC) with 1.5% by weight aqueous formic acid as eluent and cross-linked poly-hydroxyethyl methacrylate as stationary phase (TSKgel GMPWXL column) and by using an Rl detector and Pullulan standards (PSS GmbH, Mainz, Germany) for calibration..

A suitable polyethyleneimine starting material in the context of this invention may, for example, be a homopolymer of ethyleneimine conforming to the (empirical) formula -(CH ₂ -CH ₂ -NH) _n - ; in which n ranges from about 40 to about 120. Preferably n ranges from about 40 to about 60.

The polyethyleneimine starting material can vary in shape, including for example linear, branched, dendritic (hyperbranched) or comb-like structures, depending on the method of manufacture. Methods for the manufacture of such materials are generally acid-catalyzed reactions to open the ring of ethyleneimine, also known as aziridine. Examples of suitable polyethyleneimine starting materials for use in the invention have a branched structure comprising three types of subunits, which may be randomly distributed. The subunits which make up the polymer are primary amine units having the formula:

[H2N-CH2CH2]- and -NH ₂

which terminate the polymer main chain and any branching chains;

secondary amine units having the formula

-[N(H)CH ₂ CH ₂ ]- and tertiary amine units having the formula

-[N(B)CH ₂ CH ₂ ]- which are the branching points of the polymer, B representing a continuation of the chain structure by branching.

Branches may be ethyleneamino groups such as - CH2CH2-NH2 groups; or longer groups such as -(CH ₂ CH2)-N(CH2CH ₂ NH2)2 or -(CH ₂ CH2)-N(H)CH2CH ₂ NH2 groups. The mixture of primary, secondary, and tertiary amine units respectively may be in any molar ratio, including for example in a molar ratio of about 1 :1 :1 to about 1 :2:1. The molar ratio of primary, secondary, and tertiary amine units respectively may for example be determined by ¹³ C-NMR or ¹⁵ N-NMR spectroscopy, preferably in D2O. The degree of branching can be defined as follows: DB = D+T/D+T+L with D (dendritic) corresponding to the fraction of tertiary amine units, L (linear) corresponding to the fraction of secondary amine units and T (terminal) corresponding to the fraction of primary amine units. Suitably DB ranges from 0.25 to 0.95, preferably from 0.30 to 0.80, and more preferably from 0.5 to 0.8.

In the above polyethyleneimine starting material, each primary or secondary amine hydrogen atom represents a reactive site for subsequent ethoxylation. Preferably most or all of such hydrogen atoms are replaced by polyoxyethylene side chains, to form the ethoxylated polyethyleneimine for use in the invention. The polyoxyethylene side chains may suitably correspond to the formula R-(EO) _n -, in which (EO) _n represents an ethylene oxide block; n is a number from 25 to 40, preferably from 25 to 35; and R is hydrogen.

Preferred polyethyleneimine starting materials in the context of this invention display a polydispersity Q = M _w /M _n of 3.4 at most, for example in the range of from 1.1 to 3.0, more preferably in the range of from 1 .3 to 2.5 and most preferably from 1.5 to 2.0. Preferred polyethyleneimine starting materials in the context of this invention have a primary amine value in the range of from 1 to 1000 mg KOH/g, preferably from 10 to 500 mg KOH/g, most preferred from 50 to 300 mg KOH/g. The primary amine value can be determined according to ASTM D2074-07.

Preferred polyethyleneimine starting materials in the context of this invention have a secondary amine value in the range of from 10 to 1000 mg KOH/g, preferably from 50 to 500 mg KOH/g, most preferred from 50 to 500 mg KOH/g. The secondary amine value can be determined according to ASTM D2074-07.

Preferred polyethyleneimine starting materials in the context of this invention have a tertiary amine value in the range of from 1 to 300 mg KOH/g, preferably from 5 to 200 mg KOH/g, most preferred from 10 to 100 mg KOH/g. The tertiary amine value can be determined according to ASTM D2074-07.

The polyethyleneimine starting material may be pretreated (for example with a

combination of water removal and degassing) before commencement of the ethoxylation stage.

A standard procedure for the ethoxylation stage involves reacting the polyethyleneimine starting material with at least sufficient ethylene oxide to provide 2-hydroxyethyl groups at each reactive site (i.e. 1 ethylene oxide (EO) group per primary or secondary amine hydrogen atom in the polyethyleneimine molecule). The reaction product so obtained is then condensed with the remaining amount of ethylene oxide, typically in the presence of a basic catalyst.

A preferred procedure for the ethoxylation stage is a two-step procedure requiring the adjustment of the amount of ethylene oxide which is added in the first (and second) step to a certain range. This preferred procedure (hereinafter termed“strong under- ethoxylation process”) involves reacting, in a first step (1 ), the polyethyleneimine starting material with ethylene oxide in a quantity of significantly less than one molar equivalent, such as in an amount of 0.01 to 0.85, preferably 0.1 to 0.7, more preferably 0.1 to 0.6 and most preferably from 0.1 to 0.5 EO groups per primary or secondary amine hydrogen atom in the polyethyleneimine molecule. Preferably step (1 ) is carried out in the absence of a catalyst and in an aqueous solution (which may be a solution of from 50 to 99%, preferably from 75 to 99% by weight of the polyethylene starting material in water). Step (1 ) may also be carried out in the absence of a catalyst and in the absence of water. The temperature during step (1 ) is normally in the range of about 90° to 180°C, preferably 100° to 170°C, more preferably 110° to 160°C and most preferably 120° to 145°C.

In a second step (2), the reaction product obtained from step (1 ), i.e. partially ethoxylated polyethyleneimine, is reacted with the remaining amount of ethylene oxide in the presence of a basic catalyst. The second step (2) is preferably carried out at a temperature from 100° to 250 °C, and more preferably 120° to 180° C.

Examples of suitable basic catalysts include alkali metal (e.g. sodium or potassium) hydroxides; alkali metal (e.g. sodium or potassium) alkoxides such as potassium methylate (KOCH3), potassium tert-butoxide, sodium ethoxide and sodium methylate (NaOCH3); alkali metal or alkaline earth metal hydrides such as sodium hydride and calcium hydride, and alkali metal (e.g. sodium or potassium) carbonates such as sodium carbonate and potassium carbonate. Potassium hydroxide is preferred.

The final product obtained is ethoxylated polyethyleneimine (EPEI). The total degree of ethoxylation per reactive site can be determined according to the following formula: E/(AR), in which E is the total number of moles of ethylene oxide condensed (including hydroxyethylation), A is the number of moles of the polyethyleneimine starting material, and R is the number of reactive sites for the polyethyleneimine starting material.

Ethoxylated polyethyleneimines (EPEI) for use in the invention may generally have a weight average molecular weight (M _w ) of 25000 to 120000 g/mol, preferably 30000 to 100000 g/mol, more preferably 35000 to 90000 g/mol and most preferably from 40000 to 50000 g/mol, determined by gel permeation chromatography (GPC) with 0.05 % by weight potassium trifluoroacetate in hexafluoroisopropanol (HFIP) as eluent and cross- linked polystyrene/divinylbenzene as stationary phase (PL HFIPGel column; MALLS detector).

Preferred ethoxylated polyethyleneimines for use in the invention correspond to the following general formula (I): [E ₂ N-CH2CH2]w[N(E)CH2CH2]x[N(B)CH2CH2]y-NE2 (I) in which E represents a polyoxyethylene side chain corresponding to the formula

R-(EO) _n - as described above; B represents a continuation of the chain structure by branching; w,x and y are each independently from about 1 to 100 and (w + x + y) ranges from about 40 to about 120. Preferably (w + x + y) ranges from about 40 to about 60. The subunits making up the polymer of formula (I) may be randomly distributed. Generally, w:x:y ranges from about 1 :1 :1 to about 1 :2:1.

Particularly preferred ethoxylated polyethyleneimines for use in the invention and corresponding to the above general formula (I) may be produced using the strong under- ethoxylation process as is further described above.

Mixtures of any of the above described materials may also be used.

In the composition of the invention, the level of EPEI (b) preferably ranges from 0.5 to 10%, more preferably from 0.7 to 5% (by weight based on the total weight of the composition).

Liquid laundry detergents

The term“laundry detergent” in the context of this invention denotes formulated compositions intended for and capable of wetting and cleaning domestic laundry such as clothing, linens and other household textiles. The term“linen” is often used to describe certain types of laundry items including bed sheets, pillow cases, towels, tablecloths, table napkins and uniforms. Textiles can include woven fabrics, non-woven fabrics, and knitted fabrics; and can include natural or synthetic fibres such as silk fibres, linen fibres, cotton fibres, polyester fibres, polyamide fibres such as nylon, acrylic fibres, acetate fibres, and blends thereof including cotton and polyester blends.

Examples of liquid laundry detergents include heavy-duty liquid laundry detergents for use in the wash cycle of automatic washing machines, as well as liquid fine wash and liquid colour care detergents such as those suitable for washing delicate garments (e.g. those made of silk or wool) either by hand or in the wash cycle of automatic washing machines. The term“liquid” in the context of this invention denotes that a continuous phase or predominant part of the composition is liquid and that the composition is flowable at 15°C and above. Accordingly, the term“liquid” may encompass emulsions, suspensions, and compositions having flowable yet stiffer consistency, known as gels or pastes. The viscosity of the composition may suitably range from about 200 to about 10,000 mPa.s at 25°C at a shear rate of 21 sec ¹ . This shear rate is the shear rate that is usually exerted on the liquid when poured from a bottle. Pourable liquid detergent compositions generally have a viscosity of from 200 to 2,500 mPa.s, preferably from 200 to 1500 mPa.s.

Liquid detergent compositions which are pourable gels generally have a viscosity of from 1 ,500 mPa.s to 6,000 mPa.s, preferably from 1 ,500 mPa.s to 2,000 mPa.s.

A composition of the invention may generally comprise from 5 to 95%, preferably from 10 to 90%, more preferably from 15 to 85% water (by weight based on the total weight of the composition). The composition may also incorporate non-aqueous carriers such as hydrotropes, co-solvents and phase stabilizers. Such materials are typically low molecular weight, water-soluble or water-miscible organic liquids such as C1 to C5 monohydric alcohols (such as ethanol and n- or i-propanol); C2 to C6 diols (such as monopropylene glycol and dipropylene glycol); C3 to C9 triols (such as glycerol);

polyethylene glycols having a weight average molecular weight (M _w ) ranging from about 200 to 600; C1 to C3 alkanolamines such as mono-, di- and triethanolamines; and alkyl aryl sulfonates having up to 3 carbon atoms in the lower alkyl group (such as the sodium and potassium xylene, toluene, ethylbenzene and isopropyl benzene (cumene) sulfonates).

Mixtures of any of the above described materials may also be used.

Non-aqueous carriers, when included, may be present in an amount ranging from 0.1 to 20%, preferably from 1 to 15%, and more preferably from 3 to 12% (by weight based on the total weight of the composition).

The composition of the invention preferably has a pH in the range of 5 to 9, more preferably 6 to 8, when measured on dilution of the composition to 1 % using

demineralised water. The composition of the invention comprises from 6 to 50% (by weight based on the total weight of the composition) of one or more detersive surfactants (a) selected from non- soap anionic surfactants, nonionic surfactants and mixtures thereof.

The term“detersive surfactant” in the context of this invention denotes a surfactant which provides a detersive (i.e. cleaning) effect to laundry treated as part of a domestic laundering process.

Non-soap anionic surfactants for use in the invention are typically salts of organic sulfates and sulfonates having alkyl radicals containing from about 8 to about 22 carbon atoms, the term“alkyl” being used to include the alkyl portion of higher acyl radicals. Examples of such materials include alkyl sulfates, alkyl ether sulfates, alkaryl sulfonates, alpha- olefin sulfonates and mixtures thereof. The alkyl radicals preferably contain from 10 to 18 carbon atoms and may be unsaturated. The alkyl ether sulfates may contain from one to ten ethylene oxide or propylene oxide units per molecule, and preferably contain one to three ethylene oxide units per molecule. The counterion for anionic surfactants is generally an alkali metal such as sodium or potassium; or an ammoniacal counterion such as monoethanolamine, (MEA) diethanolamine (DEA) or triethanolamine (TEA). Mixtures of such counterions may also be employed.

A preferred class of non-soap anionic surfactant for use in the invention includes alkylbenzene sulfonates, particularly linear alkylbenzene sulfonates (LAS) with an alkyl chain length of from 10 to 18 carbon atoms. Commercial LAS is a mixture of closely related isomers and homologues alkyl chain homologues, each containing an aromatic ring sulfonated at the“para” position and attached to a linear alkyl chain at any position except the terminal carbons. The linear alkyl chain typically has a chain length of from 1 1 to 15 carbon atoms, with the predominant materials having a chain length of about C12. Each alkyl chain homologue consists of a mixture of all the possible sulfophenyl isomers except for the 1 -phenyl isomer. LAS is normally formulated into compositions in acid (i.e. HLAS) form and then at least partially neutralized in-situ.

Also suitable are alkyl ether sulfates having a straight or branched chain alkyl group having 10 to 18, more preferably 12 to 14 carbon atoms and containing an average of 1 to 3EO units per molecule. A preferred example is sodium lauryl ether sulfate (SLES) in which the predominantly C12 lauryl alkyl group has been ethoxylated with an average of 3EO units per molecule.

Some alkyl sulfate surfactant (PAS) may be used, such as non-ethoxylated primary and secondary alkyl sulphates with an alkyl chain length of from 10 to 18.

Mixtures of any of the above described materials may also be used. A preferred mixture of non-soap anionic surfactants for use in the invention comprises linear alkylbenzene sulfonate (preferably Cn to C15 linear alkyl benzene sulfonate) and alkyl ether sulfate (preferably C10 to C18 alkyl sulfate ethoxylated with an average of 1 to 3 EO).

The total level of non-soap anionic surfactant may suitably range from 5 to 30% (by weight based on the total weight of the composition).

Nonionic surfactants for use in the invention are typically polyoxyalkylene compounds, i.e. the reaction product of alkylene oxides (such as ethylene oxide or propylene oxide or mixtures thereof) with starter molecules having a hydrophobic group and a reactive hydrogen atom which is reactive with the alkylene oxide. Such starter molecules include alcohols, acids, amides or alkyl phenols. Where the starter molecule is an alcohol, the reaction product is known as an alcohol alkoxylate. The polyoxyalkylene compounds can have a variety of block and heteric (random) structures. For example, they can comprise a single block of alkylene oxide, or they can be diblock alkoxylates or triblock alkoxylates. Within the block structures, the blocks can be all ethylene oxide or all propylene oxide, or the blocks can contain a heteric mixture of alkylene oxides. Examples of such materials include aliphatic alcohol ethoxylates such as Cs to C18 primary or secondary linear or branched alcohol ethoxylates with an average of from 2 to 40 moles of ethylene oxide per mole of alcohol.

A preferred class of nonionic surfactant for use in the invention includes aliphatic Cs to C18, more preferably C12 to C15 primary linear alcohol ethoxylates with an average of from 3 to 20, more preferably from 5 to 10 moles of ethylene oxide per mole of alcohol.

Mixtures of any of the above described materials may also be used. The total level of nonionic surfactant may suitably range from 0 to 25% (by weight based on the total weight of the composition).

A preferred mixture of non-soap anionic and nonionic surfactants for use in the invention comprises linear alkylbenzene sulfonate (preferably Cn to C ₁₅ linear alkyl benzene sulfonate), sodium lauryl ether sulfate (preferably C10 to C18 alkyl sulfate ethoxylated with an average of 1 to 3 EO) and ethoxylated aliphatic alcohol (preferably C12 to C15 primary linear alcohol ethoxylate with an average of from 5 to 10 moles of ethylene oxide per mole of alcohol).

Optional ingredients

A composition of the invention may contain further optional ingredients to enhance performance and/or consumer acceptability, as follows:

Cosurfactants

A composition of the invention may contain one or more cosurfactants (such as amphoteric (zwitterionic) and/or cationic surfactants) in addition to the non-soap anionic and/or nonionic detersive surfactants described above.

Specific cationic surfactants include C8 to C18 _a ik _yi dimethyl ammonium halides and derivatives thereof in which one or two hydroxyethyl groups replace one or two of the methyl groups, and mixtures thereof. Cationic surfactant, when included, may be present in an amount ranging from 0.1 to 5% (by weight based on the total weight of the composition).

Specific amphoteric (zwitterionic) surfactants include alkyl amine oxides, alkyl betaines, alkyl amidopropyl betaines, alkyl sulfobetaines (sultaines), alkyl glycinates, alkyl carboxyglycinates, alkyl amphoacetates, alkyl amphopropionates, alkylamphoglycinates, alkyl amidopropyl hydroxysultaines, acyl taurates and acyl glutamates, having alkyl radicals containing from about 8 to about 22 carbon atoms, the term“alkyl” being used to include the alkyl portion of higher acyl radicals. Amphoteric (zwitterionic) surfactant, when included, may be present in an amount ranging from 0.1 to 5% (by weight based on the total weight of the composition). Mixtures of any of the above described materials may also be used.

Builders

A composition of the invention may contain one or more builders. Builders enhance or maintain the cleaning efficiency of the surfactant, primarily by reducing water hardness. This is done either by sequestration or chelation (holding hardness minerals in solution), by precipitation (forming an insoluble substance), or by ion exchange (trading electrically charged particles).

Builders for use in the invention can be of the organic or inorganic type, or a mixture thereof.

Suitable inorganic builders include hydroxides, carbonates, sesquicarbonates, bicarbonates, silicates, zeolites, and mixtures thereof. Specific examples of such materials include sodium and potassium hydroxide, sodium and potassium carbonate, sodium and potassium bicarbonate, sodium sesquicarbonate, sodium silicate and mixtures thereof.

Suitable organic builders include polycarboxylates, in acid and/or salt form. When utilized in salt form, alkali metal (e.g. sodium and potassium) or alkanolammonium salts are preferred. Specific examples of such materials include sodium and potassium citrates, sodium and potassium tartrates, the sodium and potassium salts of tartaric acid monosuccinate, the sodium and potassium salts of tartaric acid disuccinate, sodium and potassium ethylenediaminetetraacetates, sodium and potassium N(2-hydroxyethyl)- ethylenediamine triacetates, sodium and potassium nitrilotriacetates and sodium and potassium N-(2-hydroxyethyl)-nitrilodiacetates. Polymeric polycarboxylates may also be used, such as polymers of unsaturated monocarboxylic acids (e.g. acrylic, methacrylic, vinylacetic, and crotonic acids) and/or unsaturated dicarboxylic acids (e.g. maleic, fumaric, itaconic, mesaconic and citraconic acids and their anhydrides). Specific examples of such materials include polyacrylic acid, polymaleic acid, and copolymers of acrylic and maleic acid. The polymers may be in acid, salt or partially neutralised form and may suitably have a molecular weight (Mw) ranging from about 1 ,000 to 100,000, preferably from about 2,000 to about 85,000, and more preferably from about 2,500 to about 75,000 Mixtures of any of the above described materials may also be used. Preferred builders for use in the invention may be selected from polycarboxylates (e.g. citrates) in acid and/or salt form and mixtures thereof.

Builder, when included, may be present in an amount ranging from about 0.1 to about 20%, preferably from about 0.5 to about 15%, more preferably from about 1 to about 10% (by weight based on the total weight of the composition).

Transition metal ion chelating agents

A composition of the invention may contain one or more chelating agents for transition metal ions such as iron, copper and manganese. Such chelating agents may help to improve the stability of the composition and protect for example against transition metal catalysed decomposition of certain ingredients.

Suitable transition metal ion chelating agents include phosphonates, in acid and/or salt form. When utilized in salt form, alkali metal (e.g. sodium and potassium) or

alkanolammonium salts are preferred. Specific examples of such materials include aminotris(methylene phosphonic acid) (ATMP), 1-hydroxyethylidene diphosphonic acid (HEDP) and diethylenetriamine penta(methylene phosphonic acid (DTPMP) and their respective sodium or potassium salts. HEDP is preferred. Mixtures of any of the above described materials may also be used.

Transition metal ion chelating agents, when included, may be present in an amount ranging from about 0.1 to about 10%, preferably from about 0.1 to about 3% (by weight based on the total weight of the composition).

Fatty Acid

A composition of the invention may in some cases contain one or more fatty acids and/or salts thereof.

Suitable fatty acids in the context of this invention include aliphatic carboxylic acids of formula RCOOH, where R is a linear or branched alkyl or alkenyl chain containing from 6 to 24, more preferably 10 to 22, most preferably from 12 to 18 carbon atoms and 0 or 1 double bond. Preferred examples of such materials include saturated C12-18 fatty acids such as lauric acid, myristic acid, palmitic acid or stearic acid; and fatty acid mixtures in which 50 to 100% (by weight based on the total weight of the mixture) consists of saturated C12-18 fatty acids. Such mixtures may typically be derived from natural fats and/or optionally hydrogenated natural oils (such as coconut oil, palm kernel oil or tallow).

The fatty acids may be present in the form of their sodium, potassium or ammonium salts and/or in the form of soluble salts of organic bases, such as mono-, di- or triethanolamine.

Mixtures of any of the above described materials may also be used.

Fatty acids and/or their salts, when included, may be present in an amount ranging from about 0.25 to 5%, more preferably from 0.5 to 5%, most preferably from 0.75 to 4% (by weight based on the total weight of the composition).

For formula accounting purposes, in the formulation, fatty acids and/or their salts (as defined above) are not included in the level of surfactant or in the level of builder.

Soil release polymers

A composition of the invention will preferably include one or more soil release polymers (SRPs) which help to improve the detachment of soils from fabric by modifying the fabric surface during washing. The adsorption of a SRP over the fabric surface is promoted by an affinity between the chemical structure of the SRP and the target fibre.

SRPs for use in the invention may include a variety of charged (e.g. anionic) as well as non-charged monomer units and structures may be linear, branched or star-shaped. The SRP structure may also include capping groups to control molecular weight or to alter polymer properties such as surface activity. The weight average molecular weight (M _w ) of the SRP may suitably range from about 1000 to about 20,000 and preferably ranges from about 1500 to about 10,000.

SRPs for use in the invention may suitably be selected from copolyesters of dicarboxylic acids (for example adipic acid, phthalic acid or terephthalic acid), diols (for example ethylene glycol or propylene glycol) and polydiols (for example polyethylene glycol or polypropylene glycol). The copolyester may also include monomeric units substituted with anionic groups, such as for example sulfonated isophthaloyl units. Examples of such materials include oligomeric esters produced by transesterification/oligomerization of poly(ethyleneglycol) methyl ether, dimethyl terephthalate (“DMT”), propylene glycol (“PG”) and poly(ethyleneglycol) (“PEG”); partly- and fully-anionic-end-capped oligomeric esters such as oligomers from ethylene glycol (“EG”), PG, DMT and Na-3,6-dioxa-8- hydroxyoctanesulfonate; nonionic-capped block polyester oligomeric compounds such as those produced from DMT, Me-capped PEG and EG and/or PG, or a combination of DMT, EG and/or PG, Me-capped PEG and Na-dimethyl-5-sulfoisophthalate, and copolymeric blocks of ethylene terephthalate or propylene terephthalate with polyethylene oxide or polypropylene oxide terephthalate

Other types of SRP for use in the invention include cellulosic derivatives such as hydroxyether cellulosic polymers, Ci-C4 alkylcelluloses and C ₄ hydroxyalkyl celluloses; polymers with poly(vinyl ester) hydrophobic segments such as graft copolymers of poly(vinyl ester), for example C1-C6 vinyl esters (such as poly(vinyl acetate)) grafted onto polyalkylene oxide backbones; poly(vinyl caprolactam) and related co-polymers with monomers such as vinyl pyrrolidone and/or dimethylaminoethyl methacrylate; and polyester-polyamide polymers prepared by condensing adipic acid, caprolactam, and polyethylene glycol.

Preferred SRPs for use in the invention include copolyesters formed by condensation of terephthalic acid ester and diol, preferably 1 ,2 propanediol, and further comprising an end cap formed from repeat units of alkylene oxide capped with an alkyl group. Examples of such materials have a structure corresponding to general formula (I):

in which R ¹ and R ² independently of one another are X-(OC2H4) _n -(OC3H6) _{m ;}

in which X is C1-4 alkyl and preferably methyl;

n is a number from 12 to 120, preferably from 40 to 50;

m is a number from 1 to 10, preferably from 1 to 7; and a is a number from 4 to 9.

Because they are averages, m, n and a are not necessarily whole numbers for the polymer in bulk.

Mixtures of any of the above described materials may also be used.

When included, a composition of the invention will generally comprise from 0.1 to 10%, preferably from 0.3 to 7%, more preferably from 0.5 to 5% (by weight based on the total weight of the composition) of one or more SRPs (such as, for example, the copolyesters of general formula (I) as are described above).

Rheology modifiers

A composition of the invention may comprise one or more rheology modifiers. Examples of such materials include polymeric thickeners and/or structurants such as

hydrophobically modified alkali swellable emulsion (HASE) copolymers. Exemplary HASE copolymers for use in the invention include linear or crosslinked copolymers that are prepared by the addition polymerization of a monomer mixture including at least one acidic vinyl monomer, such as (meth)acrylic acid (i.e. methacrylic acid and/or acrylic acid); and at least one associative monomer. The term“associative monomer” in the context of this invention denotes a monomer having an ethylenically unsaturated section (for addition polymerization with the other monomers in the mixture) and a hydrophobic section. A preferred type of associative monomer includes a polyoxyalkylene section between the ethylenically unsaturated section and the hydrophobic section. Preferred HASE copolymers for use in the invention include linear or crosslinked copolymers that are prepared by the addition polymerization of (meth)acrylic acid with (i) at least one associative monomer selected from linear or branched C8-C40 alkyl (preferably linear C12- C22 alkyl) polyethoxylated (meth)acrylates; and (ii) at least one further monomer selected from C1-C4 alkyl (meth) acrylates, polyacidic vinyl monomers (such as maleic acid, maleic anhydride and/or salts thereof) and mixtures thereof. The polyethoxylated portion of the associative monomer (i) generally comprises about 5 to about 100, preferably about 10 to about 80, and more preferably about 15 to about 60 oxyethylene repeating units.

Mixtures of any of the above described materials may also be used. When included, a composition of the invention will preferably comprise from 0.1 to 5% (by weight based on the total weight of the composition) of one or more polymeric thickeners such as, for example, the HASE copolymers which are described above.

Compositions of the invention may also have their rheology modified by use of one or more external structurants which form a structuring network within the composition.

Examples of such materials include hydrogenated castor oil, microfibrous cellulose and citrus pulp fibre. The presence of an external structurant may provide shear thinning rheology and may also enable materials such as encapsulates and visual cues to be suspended stably in the liquid.

Enzymes

A composition of the invention may comprise an effective amount of one or more enzyme selected from the group comprising, pectate lyase, protease, amylase, cellulase, lipase, mannanase and mixtures thereof. The enzymes are preferably present with

corresponding enzyme stabilizers.

Further Optional Ingredients

A composition of the invention may contain further optional ingredients to enhance performance and/or consumer acceptability. Examples of such ingredients include foam boosting agents, preservatives (e.g. bactericides), polyelectrolytes, anti-shrinking agents, anti-wrinkle agents, anti-oxidants, sunscreens, anti-corrosion agents, drape imparting agents, anti-static agents, ironing aids, colorants, pearlisers and/or opacifiers, and shading dye. Each of these ingredients will be present in an amount effective to accomplish its purpose. Generally, these optional ingredients are included individually at an amount of up to 5% (by weight based on the total weight of the composition).

Packaging and dosing

A composition of the invention may be packaged as unit doses in polymeric film soluble in the wash water. Alternatively, a composition of the invention may be supplied in multidose plastics packs with a top or bottom closure. A dosing measure may be supplied with the pack either as a part of the cap or as an integrated system. A method of laundering fabric using a composition of the invention will usually involve diluting the dose of detergent composition to obtain a wash liquor, and washing fabrics with the wash liquor so formed. The method of laundering fabric may suitably be carried out in a top-loading or front-loading automatic washing machine, or can be carried out by hand.

In automatic washing machines, the dose of detergent composition is typically put into a dispenser and from there it is flushed into the machine by the water flowing into the machine, thereby forming the wash liquor. Dosages for a typical front-loading washing machine (using 10 to 15 litres of water to form the wash liquor) may range from about 10 ml to about 100 ml, preferably about 15 to 75 ml. Dosages for a typical top-loading washing machine (using from 40 to 60 litres of water to form the wash liquor) may be higher, e.g. 100 ml or more. Lower dosages of detergent (e.g. 50 ml or less) may be used for hand washing methods (using about 1 to 10 litres of water to form the wash liquor).

A subsequent aqueous rinse step and drying the laundry is preferred.

The invention will now be further described with reference to the following non-limiting Examples.

EXAMPLES

All weight percentages are by weight based on total weight of the formulation, unless otherwise specified. Examples according to the invention are indicated by a number; whereas comparative examples (not according to the invention) are indicated by a letter.

Viscosity measurements were made using an Anton Paar rheometer at room temperature (25 °C). Liquid laundry detergent formulations were prepared having ingredients as shown in Table 1.

Table 1

The viscosities of the control formulation and the Example A formulation are shown in Table 1a. It can be seen how inclusion of the EPEI in Example A triggers a drop in formulation viscosity compared to the control. Table 1 a

A series of further formulations were prepared using a series of different grades of EPEI in an equivalent detergent base to that shown in Table 1. The formulations are shown in Table 2.

Table 2

< ^b) EPEI with polyethyleneimine backbone derived from a polyethyleneimine starting material having an average molecular weight (M _w ) of 800 g/mol (prior to ethoxylation), and polyoxyethylene side chains having an average of 15 ethoxy units per side chain bonded to the polyethyleneimine backbone;

^(G) EPEI with polyethyleneimine backbone derived from a polyethyleneimine starting material having an average molecular weight (M _w ) of 1300 g/mol (prior to ethoxylation), and polyoxyethylene side chains having an average of 25 ethoxy units per side chain bonded to the polyethyleneimine backbone;

⁽ D ⁾ EPEI with polyethyleneimine backbone derived from a polyethyleneimine starting material having an average molecular weight (M _w ) of 2000 g/mol (prior to ethoxylation), and polyoxyethylene side chains having an average of 15 ethoxy units per side chain bonded to the polyethyleneimine backbone;

^(E> EPEI with polyethyleneimine backbone derived from a polyethyleneimine starting material having an average molecular weight (M _w ) of 2000 g/mol (prior to ethoxylation), and polyoxyethylene side chains having an average of 20 ethoxy units per side chain bonded to the polyethyleneimine backbone;

material having an average molecular weight (M _w ) of 2000 g/mol (prior to ethoxylation), and polyoxyethylene side chains having an average of 25 ethoxy units per side chain bonded to the polyethyleneimine backbone;

⁽⁵ > EPEI with polyethyleneimine backbone derived from a polyethyleneimine starting material having an average molecular weight (M _w ) of 2000 g/mol (prior to ethoxylation), and polyoxyethylene side chains having an average of 30 ethoxy units per side chain bonded to the polyethyleneimine backbone;

⁽⁶ > EPEI with polyethyleneimine backbone derived from a polyethyleneimine starting material having an average molecular weight (M _w ) of 5000 g/mol (prior to ethoxylation), and polyoxyethylene side chains having an average of 20 ethoxy units per side chain bonded to the polyethyleneimine backbone; ^(7> EPEI with polyethyleneimine backbone derived from a polyethyleneimine starting material having an average molecular weight (M _w ) of 5000 g/mol (prior to ethoxylation), and polyoxyethylene side chains having an average of 25 ethoxy units per side chain bonded to the polyethyleneimine backbone;

⁽⁸ > EpEi yyjfh polyethyleneimine backbone derived from a polyethyleneimine starting material having an average molecular weight (M _w ) of 5000 g/mol (prior to ethoxylation), and polyoxyethylene side chains having an average of 30 ethoxy units per side chain bonded to the polyethyleneimine backbone;

The viscosities of the above formulations are shown in Table 2a.

Table 2a

It can be seen how Examples 4 to 8 (according to the invention) have a superior product viscosity compared to either Example A or Examples B to E(not according to the invention).

Liquid laundry detergent formulations were prepared using different grades of EPEI in a HASE thickened liquid detergent base. The formulations are shown in Table 3. Table 3

< ⁹ > EPEI with polyethyleneimine backbone derived from a polyethyleneimine starting material having an average molecular weight (M _w ) of 2000 g/mol (prior to ethoxylation), and polyoxyethylene side chains having an average of 32.5 ethoxy units per side chain bonded to the polyethyleneimine backbone (prepared by standard ethoxylation process); c ⁱ ° ⁾ EPEI with polyethyleneimine backbone derived from a polyethyleneimine starting material having an average molecular weight (M _w ) of 2000 g/mol (prior to ethoxylation), and polyoxyethylene side chains having an average of 32.5 ethoxy units per side chain bonded to the polyethyleneimine backbone (prepared by preferred ethoxylation process); c ⁱ v EPEI with polyethyleneimine backbone derived from a polyethyleneimine starting material having an average molecular weight (M _w ) of 5000 g/mol (prior to ethoxylation), and polyoxyethylene side chains having an average of 30 ethoxy units per side chain bonded to the polyethyleneimine backbone (prepared by standard ethoxylation process);

⁽¹² > EPEI with polyethyleneimine backbone derived from a polyethyleneimine starting material having an average molecular weight (M _w ) of 5000 g/mol (prior to ethoxylation), and polyoxyethylene side chains having an average of 30 ethoxy units per side chain bonded to the polyethyleneimine backbone (prepared by preferred ethoxylation process); The viscosities of the above formulations are shown in Table 3a.

Table 3a

It can be seen how Examples 9 to 12 (according to the invention) have a superior product viscosity compared to Example F (not according to the invention).

It can also be seen how Example 10 using EPEI prepared by the preferred ethoxylation process (described above) provides particularly good results, with a viscosity

performance which is superior to that of Example 9 which uses an EPEI of equivalent backbone size and degree of ethoxylation, but prepared by a standard process.

It can also be seen how Example 12 using EPEI prepared by the preferred ethoxylation process (described above) provides particularly good results, with a viscosity

performance which is superior to that of Example 1 1 which uses an EPEI of equivalent backbone size and degree of ethoxylation, but prepared by a standard process.

Liquid laundry detergent formulations were prepared using different grades of EPEI in a salt thickened detergent base. The formulations are shown in Table 4.

Table 4

The viscosities of the above formulations are shown in Table 4a. Table 4a

It can be seen how Example 13 (according to the invention) has a superior product viscosity compared to both the control and Example G (not according to the invention). Liquid laundry detergent formulations were prepared using different grades of EPEI in a salt thickened detergent base. The formulations are shown in Table 5.

Table 5

The viscosities of the above formulations are shown in Table 5a.

Table 5a

It can be seen how Examples 14 to 17 (according to the invention) have a superior product viscosity compared to Example H (not according to the invention). It can also be seen how Example 15 using EPEI prepared by the preferred ethoxylation process (described above) provides particularly good results, with a viscosity

performance which is superior to that of Example 14 which uses an EPEI of equivalent backbone size and degree of ethoxylation, but prepared by a standard process.

It can also be seen how Example 17 using EPEI prepared by the preferred ethoxylation process (described above) provides particularly good results, with a viscosity

performance which is superior to that of Example 15 which uses an EPEI of equivalent backbone size and degree of ethoxylation, but prepared by a standard process.

Cleaning performance

Liquid laundry detergent formulations were prepared having ingredients as shown in Table 6.

Table 6

The cleaning performance of the above formulations was evaluated across a variety of stains on white test cloths of cotton or polyester. The stained test cloths were washed using a 30ml dosage of test formulation in the 40°C cotton cycle of an automatic washing machine with a water supply of 26°FH. - 21

Following the wash, the cloths were rinsed, dried and then the colour measured by a reflectometer and expressed as the After-wash SRI, which is After-wash SRI = 100 - DE where DE is the difference in colour of the stained test cloth compared to an unstained control cloth. A higher SRI value indicates cleaner cloths.

Each experiment was repeated 6 times and the statistical difference calculated using a Tukey test. The results are shown in Table 6a.

Table 6a

It can be seen that the cleaning performance of Example 18 (according to the invention) is at least equivalent to that of Example I (not according to the invention).