A WATER-SOLUBLE UNIT DOSE ARTICLE COMPRISING AN ETHYLENE OXIDE- PROPYLENE OXIDE-ETHYLENE OXIDE (EO/PO/EO) TRIBLOCK COPOLYMER

FIELD OF THE INVENTION

Use of an ethylene oxide-propylene oxide-ethylene oxide (EO/PO/EO) triblock copolymer in said water-soluble unit dose articles.

BACKGROUND OF THE INVENTION

Water-soluble unit dose articles comprising liquid laundry detergent compositions are liked by consumers as being convenient and efficient to use.

Such water-soluble unit dose articles comprise water-soluble films, preferably made of polyvinyl alcohol. In order to prevent the film from becoming too brittle and/or splitting prior to use, the internal liquid laundry detergent composition needs to be formulated with non-aqueous solvents. Such non-aqueous solvents keep the film plasticized, i.e. prevent film plasticizer migration out of the film into the liquid laundry detergent composition, therefore, ensuring the film does not become too brittle. The non-aqueous nature of the solvent also prevents premature dissolution of the film, contrary to when formulating highly aqueous compositions. The non- aqueous solvents also provide physical stabilization of the liquid laundry detergent composition and control of liquid product viscosity. However, often a problem encountered is that the film can become over-plasticized due to absorption of a too high quantity of these non-aqueous solvents from the liquid laundry detergent composition by the film, leading to swelling of the film. Such swelling of the film results in the unit dose article overall lacking structural integrity, meaning the unit dose articles look‘floppy’ which consumers find undesirable.

Therefore, there exists a need in the art for a water-soluble unit dose article which comprises a water-soluble film which does not suffer from brittleness and has improved structural integrity.

It was surprisingly found that the use of an ethylene oxide-propylene oxide-ethylene oxide (EO/PO/EO) triblock copolymer in a water-soluble unit dose article improved the structural integrity of the water-soluble film, i.e. minimised film swelling, whilst still minimising film brittleness.

SUMMARY OF THE INVENTION

A first aspect of the present invention is the use of an ethylene oxide-propylene oxide- ethylene oxide (EO/PO/EO) triblock copolymer, wherein the copolymer comprises a first EO block, a second EO block and PO block and wherein the first EO block and the second EO block are linked to the PO block, to improve the strength of a water-soluble unit dose article, preferably minimised film swelling of a water-soluble unit dose article, wherein the unit dose article comprises a water-soluble film and a liquid laundry detergent composition wherein the liquid laundry detergent composition comprises the ethylene oxide -propylene oxide-ethylene oxide (EO/PO/EO) triblock copolymer.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 : Schematic illustration of the basic configuration of the unit dose article strength test.

FIG. 2: is a water-soluble unit dose article according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Use

The present invention relates to the use of an ethylene oxide -propylene oxide-ethylene oxide (EO/PO/EO) triblock copolymer to improve the strength of a water-soluble unit dose article according to the present invention, wherein the unit dose article comprises a water-soluble film and a liquid laundry detergent composition wherein the liquid laundry detergent composition comprises the ethylene oxide-propylene oxide-ethylene oxide (EO/PO/EO) triblock copolymer. Most preferably the copolymer has a molecular weight between 2500 and 3000, a propylene oxide content between 25 and 35 propylene oxide units, and an ethylene oxide content of between 10 and 15 ethylene oxide units per ethylene oxide block.

Water-soluble unit dose article

The present invention is related to a water-soluble unit dose article comprising a water- soluble film and a liquid laundry detergent composition. The water-soluble film and the liquid laundry detergent composition are disclosed in more detail below.

The water-soluble unit dose article comprises the water-soluble film shaped such that the unit-dose article comprises at least one internal compartment surrounded by the water-soluble film, and wherein the laundry detergent composition is present within said compartment. The unit dose article may comprise a first water-soluble film and a second water-soluble film sealed to one another such to define the internal compartment. The water-soluble unit dose article is constructed such that the laundry detergent composition does not leak out of the compartment during storage. However, upon addition of the water-soluble unit dose article to water, the water-soluble film dissolves and releases the contents of the internal compartment into the wash liquor.

The compartment should be understood as meaning a closed internal space within the unit dose article, which holds the detergent composition. During manufacture, a first water-soluble film may be shaped to comprise an open compartment into which the detergent composition is added. A second water-soluble film is then laid over the first film in such an orientation as to close the opening of the compartment. The first and second films are then sealed together along a seal region.

The unit dose article may comprise more than one compartment, even at least two compartments, or even at least three compartments. The compartments may be arranged in superposed orientation, i.e. one positioned on top of the other. In such an orientation the unit dose article will comprise three films, top, middle and bottom. Alternatively, the compartments may be positioned in a side-by-side orientation, i.e. one orientated next to the other. The compartments may even be orientated in a‘tyre and rim’ arrangement, i.e. a first compartment is positioned next to a second compartment, but the first compartment at least partially surrounds the second compartment, but does not completely enclose the second compartment.

Alternatively, one compartment may be completely enclosed within another compartment.

Wherein the unit dose article comprises at least two compartments, one of the

compartments may be smaller than the other compartment. Wherein the unit dose article comprises at least three compartments, two of the compartments may be smaller than the third compartment, and preferably the smaller compartments are superposed on the larger

compartment. The superposed compartments preferably are orientated side-by-side.

In a multi-compartment orientation, the laundry detergent composition according to the present invention may be comprised in at least one of the compartments. It may for example be comprised in just one compartment, or may be comprised in two compartments, or even in three compartments.

Each compartment may comprise the same or different compositions. The different compositions could all be in the same form, or they may be in different forms.

The water-soluble unit dose article may comprise at least two internal compartments, wherein the liquid laundry detergent composition is comprised in at least one of the compartments, preferably wherein the unit dose article comprises at least three compartments, wherein the detergent composition is comprised in at least one of the compartments.

The water-soluble unit dose article according to the invention comprises at least one compartment comprising a liquid detergent composition. The liquid detergent composition according to the invention comprises an ethylene oxide -propylene oxide-ethylene oxide

(EO/PO/EO) triblock copolymer. Without wishing to be bound by theory, it is believed that the ethylene oxide-propylene oxide-ethylene oxide (EO/PO/EO) triblock copolymer reduces film swelling which results in increased film tightness, and hence unit dose article tightness and overall strength. A further benefit of the present invention is it allows for overall reduced levels of non-aqueous solvent whilst still ensuring unit dose article strength and minimized film brittleness, and minimized instability of the liquid laundry detergent composition. Yet a further benefit, is that the ethylene oxide-propylene oxide-ethylene oxide (EO/PO/EO) triblock copolymer provides non-ionic surfactant cleaning benefits, especially grease cleaning benefits. This is especially beneficial in the compacted liquid laundry detergent compositions in a water- soluble unit dose article. Hence the ethylene oxide-propylene oxide-ethylene oxide (EO/PO/EO) triblock copolymer provides a double benefit of improving water-soluble unit dose article strength and providing non-ionic surfactant cleaning benefits. This means that non-aqueous solvent and/or fatty alcohol ethoxylate levels in the water-soluble unit dose article can be reduced without compromise on unit dose article strength, film brittleness or cleaning performance.

Water-soluble film

The film of the present invention is soluble or dispersible in water. The water-soluble film preferably has a thickness of from 20 to 150 micron, preferably 35 to 125 micron, even more preferably 50 to 110 micron, most preferably about 76 micron.

Preferably, the film has a water- solubility of at least 50%, preferably at least 75% or even at least 95%, as measured by the method set out here after using a glass-filter with a maximum pore size of 20 microns:

5 grams ± 0.1 gram of film material is added in a pre- weighed 3L beaker and 2L ± 5ml of distilled water is added. This is stirred vigorously on a magnetic stirrer, Labline model No. 1250 or equivalent and 5 cm magnetic stirrer, set at 600 rpm, for 30 minutes at 30°C. Then, the mixture is filtered through a folded qualitative sintered-glass filter with a pore size as defined above (max. 20 micron). The water is dried off from the collected filtrate by any conventional method, and the weight of the remaining material is determined (which is the dissolved or dispersed fraction). Then, the percentage solubility or dispersability can be calculated.

Preferred film materials are preferably polymeric materials. The film material can, for example, be obtained by casting, blow-moulding, extrusion or blown extrusion of the polymeric material, as known in the art. Preferred polymers, copolymers or derivatives thereof suitable for use as unit dose article material are selected from polyvinyl alcohols, polyvinyl pyrrolidone, polyalkylene oxides, acrylamide, acrylic acid, cellulose, cellulose ethers, cellulose esters, cellulose amides, polyvinyl acetates, polycarboxylic acids and salts, polyaminoacids or peptides, polyamides,

polyacrylamide, copolymers of maleic/acrylic acids, polysaccharides including starch and gelatine, natural gums such as xanthum and carragum. More preferred polymers are selected from polyacrylates and water-soluble acrylate copolymers, methylcellulose,

carboxymethylcellulose sodium, dextrin, ethylcellulose, hydroxyethyl cellulose, hydroxypropyl methylcellulose, maltodextrin, polymethacrylates, and most preferably selected from polyvinyl alcohols, polyvinyl alcohol copolymers and hydroxypropyl methyl cellulose (HPMC), and combinations thereof. Preferably, the level of polymer in the film material, for example a PVA polymer, is at least 60%. The polymer can have any weight average molecular weight, preferably from about 1000 to 1,000,000, more preferably from about 10,000 to 300,000 yet more preferably from about 20,000 to 150,000.

Mixtures of polymers can also be used as the pouch material.

Preferably, the water-soluble film comprises polyvinyl alcohol polymer or copolymer, preferably a blend of polyvinylalcohol polymers and/or polyvinylalcohol copolymers, preferably selected from sulphonated and carboxylated anionic polyvinylalcohol copolymers especially carboxylated anionic polyvinylalcohol copolymers, most preferably a blend of a polyvinylalcohol homopolymer and a carboxylated anionic polyvinylalcohol copolymer.

Preferred films exhibit good dissolution in cold water, meaning unheated distilled water. Preferably such films exhibit good dissolution at temperatures of 24°C, even more preferably at l0°C. By good dissolution it is meant that the film exhibits water-solubility of at least 50%, preferably at least 75% or even at least 95%, as measured by the method set out here after using a glass-filter with a maximum pore size of 20 microns, described above.

Preferred films are those supplied by Monosol under the trade references M8630, M8900, M8779, M8310.

The film may be opaque, transparent or translucent. The film may comprise a printed area.

The area of print may be achieved using standard techniques, such as flexographic printing or inkjet printing.

The film may comprise an aversive agent, for example a bittering agent. Suitable bittering agents include, but are not limited to, naringin, sucrose octa-acetate, quinine hydrochloride, denatonium benzoate, or mixtures thereof. Any suitable level of aversive agent may be used in the film. Suitable levels include, but are not limited to, 1 to 5000ppm, or even 100 to 2500ppm, or even 250 to 2000rpm.

Liquid laundry detergent composition

The water-soluble unit dose article comprises a liquid laundry detergent composition. The term‘liquid laundry detergent composition’ refers to any laundry detergent composition comprising a liquid capable of wetting and treating a fabric, and includes, but is not limited to, liquids, gels, pastes, dispersions and the like. The liquid composition can include solids or gases in suitably subdivided form, but the liquid composition excludes forms which are non-fluid overall, such as tablets or granules.

The liquid detergent composition can be used in a fabric hand wash operation or may be used in an automatic machine fabric wash operation.

The liquid laundry detergent composition comprises an ethylene oxide-propylene oxide- ethylene oxide (EO/PO/EO) triblock copolymer, wherein the copolymer comprises a first EO block, a second EO block and PO block wherein the first EO block and the second EO block are linked to the PO block. In other words, the PO block is positioned between the two EO blocks. The copolymer may consist of a first EO block, a second EO block and PO block wherein the first EO block and the second EO block are linked to the PO block. By‘linked to the PO block’, we herein the EO-PO-EO blocks have the following structure;

wherein Xi is preferably on average is between 2 and 90, preferably 3 and 50 more preferably between 4 and 20, even more preferably between 5 and 15, most preferably between 10 and 15;

X ₂ is preferably on average is between 2 and 90, preferably 3 and 50 more preferably between 4 and 20, even more preferably between 5 and 15, most preferably between 10 and 15;

Y is preferably on average between 15 and 70, preferably between 20 and 60, more preferably between 25 and 50, even more preferably between 25 and 40, most preferably between 25 and 35. Preferably, the liquid laundry detergent composition comprises between 1% and 10%, preferably between 2% and 8% by weight of the liquid laundry detergent composition of the ethylene oxide-propylene oxide-ethylene oxide (EO/PO/EO) triblock copolymer.

Preferably, the ethylene oxide-propylene oxide-ethylene oxide (EO/PO/EO) triblock copolymer has an average propylene oxide chain length of between 15 and 70, preferably between 20 and 60, more preferably between 25 and 50, even more preferably between 25 and 40, most preferably between 25 and 35 propylene oxide units.

Preferably, the ethylene oxide-propylene oxide-ethylene oxide (EO/PO/EO) triblock copolymer has an average molecular weight of between 1000 and 10,000, preferably between 1500 and 5000 more preferably between 2000 and 4500, even more preferably between 2500 and 4000, most preferably between 2500 and 3000.

Preferably, each ethylene oxide chain independently has an average chain length of between 2 and 90, preferably 3 and 50 more preferably between 4 and 20, even more preferably between 5 and 15, most preferably between 10 and 15 ethylene oxide units.

Preferably, the copolymer comprises on average between 10% and 90%, preferably between 20% and 70%, most preferably between 30% and 50% by weight of the copolymer of the combined ethylene-oxide blocks. Most preferably the total ethylene oxide content is split over the two ethylene oxide blocks such that each ethylene oxide block comprises on average between 40% and 60% preferably between 45% and 55%, even more preferably between 48% and 52%, most preferably 50% of the total number of ethylene oxide units, wherein the percentage of both ethylene oxide blocks accounts for 100% of the ethylene oxide units present.

Most preferably the copolymer has an average molecular weight between 2500 and 3000, an average propylene oxide content between 25 and 35 propylene oxide units, and an average ethylene oxide content of between 10 and 15 ethylene oxide units per ethylene oxide block. Without wishing to be bound by theory, a further benefit of the ethylene oxide-propylene oxide- ethylene oxide (EO/PO/EO) triblock copolymer is that they exhibit good safety profiles. Most preferred are copolymers having an average molecular weight between 2500 and 3000, an average propylene oxide content between 25 and 35 propylene oxide units, and an average ethylene oxide content of between 10 and 15 ethylene oxide units per ethylene oxide block as these have the best safety profile of this class of copolymers wherein they especially exhibit minimal skin and eye irritation if accidentally contacted with skin or eye.

Suitable ethylene oxide - propylene oxide - ethylene oxide triblock copolymers are commercially available under the Pluronic PE series from the BASF company, or under the Tergitol L series from the Dow Chemical Company. A particularly suitable material is Pluronic PE 6400 or Tergitol L64.

Without wishing to be bound by theory, a further benefit of the ethylene oxide-propylene oxide-ethylene oxide (EO/PO/EO) triblock copolymer is that they exhibit good safety profiles wherein they especially exhibit minimal skin and eye irritation if accidentally contacted with skin or eye.

Preferably, the liquid laundry detergent composition comprises a non-soap anionic surfactant, preferably wherein the non-soap anionic surfactant comprises linear alkylbenzene sulphonate, alkoxylated alkyl sulphate or a mixture thereof, more preferably a mixture thereof wherein the ratio of linear alkylbenzene sulphonate to alkoxylated alkyl sulphate preferably the ratio of linear alkylbenzene sulphonate to ethoxylated alkyl sulphate is from 1:2 to 20:1, preferably from 1.1:1 to 15:1, more preferably from 1.2:1 to 10:1, even more preferably from 1.3:1 to 5:1, even more preferably from 1.4:1 to 3: 1, most preferably from 1.4:1 to 2.5:1.

Preferably the ethoxylated alkyl sulphate is an alkyl ethoxy sulphate comprising a mol average of 1 to 5, preferably 2 to 4, most preferably 3 ethylene oxide units per alkyl chain.

The liquid laundry detergent composition may comprise between 10% and 60%, preferably between 15% and 50% by weight of the liquid laundry detergent composition of surfactant. In terms of the present invention, the ethylene oxide -propylene oxide-ethylene oxide (EO/PO/EO) triblock copolymer of the present invention is not defined as a surfactant and so does not contribute to the total level of surfactant. More preferably, the liquid laundry detergent composition comprises between 5% and 50%, preferably between 15% and 45%, more preferably between 25% and 40%, most preferably between 30% and 40% by weight of the detergent composition of the non-soap anionic surfactant.

Preferably, the liquid laundry detergent composition comprises less than 10% preferably less than 5%, preferably less than 3%, more preferably less than 2.5% by weight of the laundry detergent composition of a fatty alcohol ethoxylate non-ionic surfactant.

Preferably, the liquid laundry detergent composition comprises between 1.5% and 20%, more preferably between 2% and 15%, even more preferably between 3% and 10%, most preferably between 4% and 8% by weight of the liquid detergent composition of soap, preferably a fatty acid salt, more preferably an amine neutralized fatty acid salt, wherein preferably the amine is an alkanolamine more preferably selected from monoethanolamine, diethanolamine, triethanolamine or a mixture thereof, more preferably monoethanolamine·

The liquid laundry detergent composition preferably comprises a non-aqueous solvent preferably selected from 1 ,2-propanediol, dipropylene glycol, tripropyleneglycol, glycerol, sorbitol or a mixture thereof. More preferably the liquid laundry detergent composition comprises between 10% and 40%, preferably between 15% and 30% by weight of the liquid laundry detergent composition of the non-aqueous solvent. Preferably, the weight ratio of non- aqueous solvent selected from 1, 2-propanediol, dipropylene glycol, tripropyleneglycol, glycerol, sorbitol or a mixture thereof to the ethylene oxide -propylene oxide-ethylene oxide tri-block copolymer is between 1:1 and 10: 1 more preferably between 2:1 and 5:1.

The liquid laundry detergent composition preferably comprises an alkanolamine preferably selected from monoethanolamine, triethanolamine, and mixtures thereof, preferably monoethanolamine. The alkanolamine preferably is present between 5% and 15% by weight of the liquid laundry detergent composition.

Preferably, the liquid laundry detergent composition comprises between 0.5% and 15%, preferably between 5% and 13% by weight of the liquid laundry detergent composition of water.

The liquid laundry detergent composition may comprise an enzyme. Preferably, the enzyme is selected from the group comprising hemicellulases, peroxidases, proteases, cellulases, xylanases, lipases, phospholipases, esterases, cutinases, pectinases, keratanases, reductases, oxidases, phenoloxidases, lipoxygenases, ligninases, pullulanases, tannases, pentosanases, malanases, b-glucanases, arabinosidases, hyaluronidase, chondroitinase, laccase, and amylases, or mixtures thereof, preferably proteases, amylases, lipases, cellulases and mixtures thereof, preferably lipases.

The liquid laundry detergent composition may comprise a further polymer selected from the group comprising an alkoxylated polyethyleneimine, preferably an ethoxylated

polyethyleneimine, a cationically modified polysaccharide, preferably a cationically modified hydroxyethylcellulose, a carboxymethylcellulose, preferably a hydrophobically modified carboxymethylcellulose, a polyester terephthalate soil release polymer, preferably an anionic polyester terephthalate soil release polymer, and an amphiphilic graft soil release polymer, preferably a polyethylene glycol graft polymer comprising a polyethylene glycol backbone and hydrophobic vinyl acetate side chains, or a mixture thereof. Preferably, the liquid laundry detergent composition comprises independently between 0.1% and 10%, preferably between 0.25% and 7%, more preferably between 0.5% and 5% by weight of the liquid laundry detergent composition of each of these polymers.

The liquid laundry detergent composition may further comprise an adjunct ingredient selected from builders, dye transfer inhibiting agents, dispersants, enzymes,

enzyme stabilizers, catalytic materials, bleach, bleach activators, polymeric dispersing agents, antiredeposition agents, suds suppressors, aesthetic dyes, opacifiers, perfumes, perfume delivery systems, structurants, hydrotropes, processing aids, pigments and mixtures thereof.

Preferably, the liquid laundry detergent composition has a pH between 6 and 10, more preferably between 6.5 and 8.9, most preferably between 7 and 8. The pH of the liquid laundry detergent composition may be measured as a 10% dilution in demineralized water at 20°C.

The liquid detergent composition preferably has a viscosity of between 100 and 1000 cPa.s, measured at a shear rate of 20/s at 20 °C on a TA instruments AR-G2 or AR2000 using a 40mm plate geometry and a 500 micron gap size.

Without wishing to be bound by theory, low viscosity allows higher manufacturing line speed, however, there is an increased risk of‘splashing’ and‘stringing’ in which liquid detergent accidentally contaminates the seal area and so results in seal defects. Such seal defects affects the structural integrity of the unit dose article. Increasing the viscosity avoids the issues of seal contamination but reduces manufacturing line speed. The preferred viscosity of the present invention allows for efficient manufacture line speed whilst minimizing seal contamination.

Method of washing

A further aspect of the present invention is a method of washing comprising the steps of adding the water-soluble unit dose article according to the present invention to sufficient water to dilute the liquid laundry detergent composition by a factor of at least 300 fold to create a wash liquor and contacting fabrics to be washed with said wash liquor.

Without wishing to be bound by theory, when the water-soluble unit dose article is added to water, the water-soluble film dissolves releasing the internal liquid laundry detergent composition into the water. The liquid laundry detergent composition disperses in the water to create the wash liquor.

Preferably the wash liquor may comprise between 1L and 64L, preferably between 2L and 32L, more preferably between 3L and 20L of water.

Preferably, the wash liquor is at a temperature of between 5oC and 90oC, preferably between lOoC and 60oC, more preferably between l2oC and 45oC, most preferably between l5oC and 40oC.

Preferably, washing the fabrics in the wash liquor takes between 5 minutes and 50 minutes, preferably between 5 minutes and 40 minutes, more preferably between 5 minutes and 30 minutes, even more preferably between 5 minutes and 20 minutes, most preferably between 6 minutes and 18 minutes to complete.

Preferably, the wash liquor comprises between lkg and 20 kg, preferably between 3kg and l5kg, most preferably between 5 and 10 kg of fabrics. The wash liquor may comprise water of any hardness preferably varying between 0 gpg to 40gpg.

The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as“40 mm” is intended to mean “about 40 mm.” EXAMPLES

Example 1

The impact of partially replacing the non-aqueous solvent system within a water soluble unit dose liquid laundry detergent formulation by an ethylene oxide-propylene oxide-ethylene oxide (EO/PO/EO) triblock copolymer according to the invention, has been studied on overall film swelling and linked unit dose article strength and tightness properties. From the data tabulated below it can clearly be seen that reduced film swelling and hence stronger and tighter unit dose articles are obtained with the compositions according to the invention comprising the ethylene oxide-propylene oxide-ethylene oxide (EO/PO/EO) triblock copolymer (Compositions 1 to 3) compared to Comparative Composition A lacking the ethylene oxide-propylene oxide- ethylene oxide (EO/PO/EO) triblock copolymer.

Test compositions :

*ethoxylated polyethyleneimine having an average degree of ethoxylation of 20 per EO c lain and a polyethyleneimine backbone with MW of about 600

**poly ethylene glycol graft polymer comprising a polyethylene glycol backbone (Pluriol E6000) and hydrophobic vinyl acetate side chains, comprising 40% by weight of the polymer system of a

polyethylene glycol backbone polymer and 60% by weight of the polymer system of the grafted vinyl acetate side chains

Test methods :

Film swelling :

A film sample was prepared of a water soluble PVOH film intended to be used to form a sealed compartment enclosing the comparative composition and liquid household detergent compositions according to the invention described above. The film/juice ratio in the immersion is about 1:100; we typically use 5 replicates/test. The bottom of a clean inert glass recipient was covered with a thin layer of liquid and the film to be tested was spread on the liquid; air bubbles trapped under the film were gently pushed towards the sides. The remaining liquid was then gently poured on top of the film, in such a way that the film was fully immersed into the liquid. The film should remain free of wrinkles and no air bubbles should be in contact with the film. The film stayed in contact with the liquid and was stored under closed vessel conditions for 5 days at 50°C and 1 night at 2l°C. A separate glass recipient was used for each test. The film was then removed from the storage vessel, and the excess liquid was removed from the film. A piece of paper was put on the film which was laid on top of a bench paper, and then the film was wiped dry thoroughly with dry paper. The weight of the film was measured pre and post immersion testing, and the relative gain weight has been calculated and expressed as a % change according to below formula ;

% change = (end-weight/starting weight)* 100.

Unit dose article Strength :

This test method describes the practice for determining the unit dose article strength using the Instron Universal Materials Testing instrument (Instron Industrial Products, 825 University Ave., Norwood, MA 02062-2643) with a load cell of maximum 100 kN (kilo Newton). Via compression of a unit dose article, this method determines the overall strength (in Newtons) of the unit dose article by putting pressure on the film and seal regions. Unit dose article strength (in Newtons) is defined as the maximum load a unit dose article can support before it breaks. Unit dose articles opening at the seal area at a pressure lower than 250N are reported as seal failures, and are not taken into account when determining average unit dose article strength.

The liquid detergent compositions have been enclosed in a water soluble PVA film, more particularly a PVA film comprising a blend of a polyvinylalcohol homopolymer and a carboxylated anionic polyvinylalcohol copolymer resin, to obtain a water soluble unit dose article for pouch strength / tightness testing, the water soluble unit dose article matching the Ariel 3-in-l Pods design, as commercially available in the UK in January 2018 and visualized in Figure 2, having filled all 3 compartments therein by one of the test compositions described above respectively (i.e. each of the three compartments had the same composition). The same water soluble PVA film has been used for the film swelling experiment. The water soluble film has been pre-heated and drawn into a cavity through vacuum to form a first open compartment into which the test detergent composition has been dosed. In parallel the 2 top side by side compartments have been formed by drawing a pre-heated water soluble film in a second side by side cavity to form 2 side by side open compartments into which the same test detergent is dosed, followed by closing and sealing these filled side by side compartments by a second film. The closed side by side compartments are consequently added and sealed on top of the first open and filled cavity to obtain the superposed multi-compartment water soluble article being tested.

The unit dose article strength was measured no sooner than two hours after unit dose article production so that the film/unit dose articles had time to set after converting. The method was performed in a room environment between 40-50% relative humidity (RH) and 22-24°C. Stored unit dose articles were allowed to re-equilibrate to the testing room environment for one hour prior to testing.

FIG. 1. shows a schematic illustration of the basic configuration of the unit dose article strength test. To measure unit dose article strength, a unit dose article 510 was enclosed in a plastic de-aerated bag 500 (150 mm by 124 mm with closure, 60 micron thick - e.g. Raja grip RGP6B) to prevent contamination of working environment upon unit dose article rupture. After enclosure in the bag, the unit dose article 510 was centered between two compression plates 520, 530 of the instrument. The unit dose article 510 was placed in an upright position, so that the width seal dimension 540 (e.g. smallest dimension within a defined rectangular plane just encompassing the seal area, 41 mm in actual unit dose articlees tested) was between the compression plates (x-direction) such that the stress was applied on the width seal. For the compression, the speed of decreasing the distance between the plates 520 and 530 is set at 60 mm/min. Ten replicates were conducted per test leg, and average unit dose article strength data, excluding seal failures as defined above, are reported (the higher the stronger the unit dose article).

Unit dose article Tightness: (the higher the better)

This test method describes the practice for determining the unit dose article tightness using the Instron Universal Materials Testing instrument (Instron Industrial Products, 825 University Ave., Norwood, MA 02062-2643) with a load cell of maximum 100 kN (kilo Newton). Via compression of a unit dose article, this method determines the residual distance between compression plates when applying a load of 10N.

The unit dose article tightness was measured no sooner than two hours after unit dose article production so that the film/unit dose articles had time to set after being made. The method was performed in a room temperature environment between 30% and 60% relative humidity and l8-25°C, most preferred between 40% and 50% relative humidity and 22-24°C. Stored unit dose articles were allowed to re-equilibrate to the testing room environment for one hour prior to testing.

The test set-up is similar as in the unit dose article strength test and as shown in FIG. 1 with the exception that the unit dose article has now been positioned with the surrounding seal plane horizontal, rather than vertical as in the unit dose article strength test, between the two compressions plates 520,530 of the instrument. To measure unit dose article tightness, a unit dose article 510 was enclosed in a plastic de-aerated bag 500 (150 mm by 124 mm with closure, 60 micron thick - e.g. Raja grip RGP6B) to prevent contamination of working environment upon accidental unit dose article rupture. After enclosure in the bag, the unit dose article 510 was centered between two compression plates 520, 530 of the instrument. The unit dose article 510 was placed in a horizontal position, so that the outer seal / flange dimension was horizontally oriented between the compression plates (y,z-direction). For the compression, the speed of decreasing the distance between the plates 520 and 530 is set at 60 mm/min, and the instrument is set for the compression plate to stop when a pressure of 0.01 kN (1 Kg) is reached. The unit dose article tightness can hence be read from the instrument display as the end distance in between the two compression plates (mm).

Test results :

Film Swelling :

A decreased degree of film swelling is observed for the compositions comprising the ethylene oxide-propylene oxide-ethylene oxide (EO/PO/EO) triblock copolymer (Compositions 1 to 3) compared to Comparative Composition A lacking the ethylene oxide-propylene oxide- ethylene oxide (EO/PO/EO) triblock copolymer.

Unit dose article Strength & Tightness :

Stronger and tighter water soluble unit dose articles are obtained with the compositions comprising the ethylene oxide-propylene oxide-ethylene oxide (EO/PO/EO) triblock copolymer (Compositions 1 to 3) compared to Comparative composition A lacking the ethylene oxide- propylene oxide-ethylene oxide (EO/PO/EO) triblock copolymer.

Example 2

A range of different ethylene oxide-propylene oxide-ethylene oxide (EO/PO/EO) triblock copolymers according to the invention has been studied by substituting the (EO/PO/EO) triblock copolymer within Composition 3 on their ability to prevent film swelling, according to the protocol described herein. Test results :

A decreased degree of film swelling is observed across all ethylene oxide-propylene oxide-ethylene oxide (EO/PO/EO) triblock copolymers tested, varying in molecular weight, degree of ethylene oxide and propylene oxide units, compared to Comparative composition A lacking the ethylene oxide-propylene oxide-ethylene oxide (EO/PO/EO) triblock copolymer.

Example 3

FIG.2 discloses a water-soluble unit dose article (1) according to the present invention. The water-soluble unit dose article (1) comprises a first water-soluble film (2) and a second water- soluble film (3) which are sealed together at a seal region (4). The liquid laundry detergent composition according to the invention (5) is comprised within the water-soluble soluble unit dose article (1).