EP2841547B1

EP2841547B1 - Structured aqueous liquid detergent

Info

Publication number: EP2841547B1
Application number: EP13713119.9A
Authority: EP
Inventors: Lee James Brennan; Adam Jan Kowalski; Geraint Paul Roberts; John Francis Wells
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 2012-04-23
Filing date: 2013-03-19
Publication date: 2016-07-13
Anticipated expiration: 2033-03-19
Also published as: ES2595218T3; ZA201407638B; CN104379716A; EP2841547A1; BR112014026433A2; IN2014MN02036A; WO2013160025A1

Description

Technical Field

This invention relates to structured aqueous detergent liquid compositions comprising water, surfactant, external structurant and enzymes, the external structurant provides rheological modification to the composition and may suspend insoluble particles in the liquid.

Background

It is desirable to formulate liquid detergents in a concentrated form. This saves on packaging, transport costs and production energy. In WO09153184 , a concentrated aqueous laundry detergent liquid is used to reduce the amount of chemicals per wash. This is achieved, without loss of detergency, by reduction of the amount of surfactant used per wash and use, in its place, of highly weight efficient enzymes and polymers to boost detergency on everyday dirt and stains. Preferred compositions use enzymes and combinations of high levels of ethoxylated polyethyleneimine polymer and polyester soil release polymer. Cellulase and pectate lyase are taught as suitable enzymes for inclusion in these compositions.
It is known to use external structurants in aqueous detergent liquids for rheological modification and suspending duty. For a concentrated liquid, the structurant can convey the idea of concentration by increasing low shear viscosity whilst allowing the composition to flow freely when poured. Insoluble particles can be suspended in such liquids to further reinforce the concentration message, for example the liquid can be pearlised by inclusion of mica particles, silver containing particles or titanium dioxide particles. The external structurant should be capable of suspending these particles, working either alone, or in combination with another rheology modifying system.
External structurants are also useful for less concentrated aqueous cleaning liquids. In such liquids, surfactant in excess of that required for detergency is often used for thickening and rheology modification. This is undesirable from an environmental standpoint, not only is more chemical sent to waste but frequently the excess surfactant causes the utilisation of more rinse water, which is a big issue when water is a scarce resource.
One well-known external structurant is hydrogenated castor oil (HCO), also known as trihydroxystearin, or castor wax, and sold under the trade name Thixcin® by Elementis. HCO is derived from chemical modification of a plant extract. Then the HCO is converted into an external structurant by crystallising it in the liquid, or in part of the liquid. This crystallisation process may impose formulation constraints, especially when using high surfactant levels. HCO structured liquids are slightly cloudy, which is undesirable when visual cues are suspended in the liquid. Because the HCO structurant is formed by cooling, its performance is reduced if the liquid is subjected to extreme temperatures, either in the supply chain, or in the hands of consumers.
It has been proposed to use bacterially produced microfibrous cellulose (MFC) as an external structurant, either on its own ( US2007/0197779 ), or more preferably in combination with HCO, as described in WO2010/048154 . Compared with HCO, MFC is more weight efficient as an external structurant. However, MFC suffers from other disadvantages. The first is that due to its very low incorporation levels it can fail to remain evenly dispersed through the liquid if air micro bubbles form and get trapped by the structuring network to buoy the MFC up. A process designed to try to overcome this problem is disclosed in WO09135765A (Unilever). No enzymes are used. The detergent formulator would prefer to avoid use of MFC due to these known processing constraints.
US patent application US2007/0197779 discloses a structurant consisting of bacterially produced MFC combined with significant levels of carboxy methylcellulose and xanthan gum as dispersion aids. Upon high shear dispersion in water, the MFC forms a 3-D network structure, which can suspend inert materials such as sand and nylon beads. The xanthan gum part of the dispersant is not a desirable ingredient for many detergent liquids. It poses constraints for inclusion of enzymes that can decompose xanthan gum. Furthermore it can have an undesirable effect in combination with cleaning and soil release polymers. Such polymers are proposed to be used at high concentrations in the detergent liquids described in WO09/153184 . Thus MFC is not a good choice for the external structuring of such detergent liquids with high levels of polymers.
WO2009/101545 describes compositions comprising MFC structurant. Exemplary compositions contain enzymes; a list of suitable enzymes is given on page 29. The preferred enzyme mixture includes cellulase. We have determined that use of cellulases with MFC reduce its suspending power and adversely affect the rheological modification imparted by the MFC. We have also discovered that MFC requires the presence of relatively high levels of surfactant to provide effective rheological modification. It would be desirable to find an alternative external structurant that would also perform at low surfactant levels and that would be compatible with a wide range of cellulase enzymes.
Based on SEM evidence, MFC forms nanofibres in concentrated aqueous detergent liquids. Uncertainties exist in scientific understanding of the impacts of such fibres, and associated public perception. For this reason, and because of the other disadvantages of MFC outlined previously, the skilled worker desires to find a better substitute for HCO than MFC appears to be.
Especially in the laundry detergent field it is normal to provide a range of products with a common chassis. Some of those products will comprise enzymes and others may be the so-called non-bio variants that are free from enzymes to allow use by consumers who prefer not to contact their laundry with enzyme containing formulations. It adds considerably to formulation complexity if the external structurant cannot be used in a common composition chassis designed to work both with and without the enzyme system adopted. It is thus highly desirable to have a chassis with a rheology modified by an external structurant that can be used with lipase and/or cellulase, particularly cellulase, or no enzyme at all and in which solid material can be reliably and stably suspended. Thus, it would be beneficial in the field of externally structured aqueous detergent compositions to have a new external structurant that does not suffer from the drawbacks of HCO and/or MFC.
US2004/0086626 describes an improved method for refining cellulose that produces a highly refined cellulosic (HRC) material. The method comprises soaking raw material from primarily parenchymal cell wall structures in an aqueous solution, using reduced temperatures and pressures, and refining the material with a plate refiner. After drying the resulting HRC fibre displays a water retention capacity of about 25 to at least about 56 g water/g dry HRC and retains moisture under conditions that are ordinarily used to remove moisture from materials. The publication suggests that the HRC fibre product can also provide excellent thickening properties and may be used in a wide variety of materials, including edible materials. Thickening and suspending properties are particularly attributed to fibres provided by sugar beets. Orange pulps are used in several examples. Apples are mentioned but no advantage is suggested for them. The main use envisaged for this product is as a food additive. The dried HRC product may be rehydrated by the use of a high shear mixer to disperse organic fibre plant mass materials rapidly into solution. Other uses mentioned are industrial thickeners, as in paint thickeners, stain thickeners, coating thickeners, and the like.
US 7981855 discloses enzyme free liquid surfactant compositions comprising up to 15 wt% surfactant, including at least 1% anionic surfactant, up to 2 wt% bacterial cellulose (preferably MFC) and from 0.001 to 5 wt% citrus fibres.
High water binding capacity Apple fibres are available for example as "Herbacel AQ plus apple fibre", from Herba Foods.

Summary of the Invention

According to the present invention there is provided a structured aqueous liquid detergent composition comprising:

at least 10 wt% water,
at least 0.5 wt% surfactant,
at least 0.0001 wt% cellulase and / or pectate lyase, and
an external structurant, characterised in that the external structurant comprises at least 0.15 wt%, preferably at least 0.2 wt%, apple fibre that has been mechanically pulped and swollen in water to an extent that it can absorb at least 10 times its own dry weight of water.

Preferably the composition comprises 0.16 to 0.35 wt% pulped apple fibre.
For suspending duty, the composition may have a yield stress greater than 0.2 Pa.
Apple fibre is derived from apple fruit; a preferred apple fibre is HERBACEL AQ Plus which, according to the supplier, is made from harvest-fresh dejuiced (and de-oiled) and carefully dried apples. Non-fibrous compounds such as plant-specific sugars, colouring and aroma components are carefully removed during several washing steps, whereby the natural cell wall structure is practically maintained in the HERBACEL AQ Plus apple fibre. The apple fruit material is pulped by subjecting it to high shear and the pulped material is referred to as pulped apple fibre (PAF). Such pulped fibres are capable of absorbing and binding a high amount of water, preferably at least 10 times their own weight of water, most preferably at least 15 times. A grade of apple fibre that has its water absorbing capacity further increased by pulping is preferred.
The amount of pulped apple fibre required to deliver an acceptably high critical stress in the final liquid is at least 0.15 wt%, preferably at least 0.2 wt%, more preferably at least 0.25 wt%.
Preferably the composition comprises cellulase. The preferred amount of cellulase is from 0.0001 to 5 wt%, even more preferably from 0.001 to 0.3 wt% active enzyme.
The external structurant is a pulped apple fibre which has undergone a mechanical treatment comprising a step of high intensity mixing in water and which material has consequently absorbed at least 10 times its own dry weight of water, preferably at least 15 times its own weight, in order to swell it. It may be derived by an environmentally friendly process from an apple fruit processing waste stream. This makes it more sustainable than many of the prior art external structurants. Furthermore, it requires no additional chemicals to aid its dispersal and it can be made as a structured premix to allow process flexibility.
Pulped apple fibre is much less expensive to produce than bacterial cellulose because its processing is simpler and it may be made from a waste stream, e.g. from fruit juice production. Over very long periods of storage (6 months) detergents structured with pulped apple fibre have been found to retain their rheology even better than corresponding detergents structured with pulped citrus fibre.
In a preferred process, the apple fibre is mechanically pulped by processing it to make a premix, preferably in combination with preservative. This is done by adding dried powdered apple fibre to at least 10 times its own weight of water and dispersing it under very high shear to further break up the apple fibres and to begin the process of hydration, or swelling. The mechanically treated apple fibre or pulped apple fibre is left in contact with the water for sufficient time for it to swell due it being fully hydrated. This can be several hours. We have found it advantageous that pulped apple fibre is kept separate from surfactant until it is fully swollen. This avoids the possibility for the surfactant to compete with the pulped apple fibre for the water. Something that becomes more of a problem as the total surfactant concentration increases. This premix pulp swelling process seems to become especially advantageous when surfactant level in the composition is 25 wt% or higher. The very high shear may be provided by a high intensity mixer such as a Silverson mixer, or by means of a High-pressure homogeniser.
The amount of pulped apple fibre in the premix is preferably from 1 to 5 wt%. More preferably from 2 to 4 wt%. Depending on the processing equipment used there may be a practical upper limit of from 3.3 to 3.5 wt% as it is advantageous that there is excess water in order to fully hydrate the pulped apple fibre.
Pulped apple fibre is complex and heterogeneous; it includes both soluble and insoluble cellular materials, which is shown to give rise to a distinctive network of 'sponges' of varying size and geometry in contrast to MFC's essentially fibrous network. Possibly due in part to this structural difference, one advantage we have found for pulped apple fibre externally structured liquid formulations is its compatibility with enzymes. In particular, cellulases, which appear to have some destabilising effect on MFC.
Cellulase and / or pectate lyase is an essential feature of the structured aqueous liquid detergent compositions of the invention. Modern detergent compositions desirably comprise cellulase, for cleaning and / or for garment care benefits. Pectate lyase may be included to assist with the removal of fruit stains, for example tomato.
Cellulases should preferably be formulated at a pH where their activity is low. Typically this is an alkaline pH, although mildly acidic conditions of down to pH 6.5 or even as low as pH 6.2 can be tolerated. An advantage of pulped apple fibre over bacterially derived microfibrous cellulose as an external structurant is that due to its lower cost and lower efficacy as a structurant the pulped apple fibre may be incorporated at much higher levels than MFC. This may further improve the resistance to destabilisation of the structuring system due to attack from cellulase in the composition. Pulped apple fibre provides a stable external structuring network in the presence of endoglucanase, which enables addition of this cellulase to a structured aqueous liquid either on its own, or more preferably in combination with other enzymes.
Given the pectin content of apple pulp it was surprising to find that the structuring system was robust in the presence of pectate lyase, an enzyme that breaks down pectin. It is thought that although the pectin is broken down this makes little or no difference to the rheology. When included, the level of pectate lyase is from 0.0001 to 5 wt%, even more preferably from 0.001 to 0.3 wt% active enzyme.
For structured detergent compositions used for cleaning hard surfaces, including hand dishwashing liquids, cellulases help to break down many food residues.
The surfactant type is not limited. Synthetic detergents are preferred. Mixtures of synthetic anionic and nonionic surfactants, or wholly anionic surfactant system or admixtures of anionic surfactants with nonionic surfactants or with amphoteric or zwitterionic surfactants may be used. It is preferred for the composition to comprise anionic (non-soap) surfactant. Particularly preferred surfactant systems are mixtures of the anionic surfactants linear alkyl benzene sulphonate and sodium lauryl ether sulphate with the nonionic surfactant ethoxylated nonionic fatty alcohol. Amphoteric surfactants, including preferably betaines, especially carbobetaines, or amine oxides are advantageously used as a cosurfactant.
The amount of surfactant may range from 0.5 to 65 wt%, preferably 2.5 to 60 wt%, more preferably from 25 to 50 wt%. The skilled worker will appreciate that the optimum surfactant concentration will largely depend on the product type and the intended mode of use.
The amount of external structurant is important. Because it is added to the remainder of the ingredients in admixture with around 20 times its weight of water, it is important to keep the amount of structurant to a minimum. Below 0.15 wt%, pulped apple fibre fails to provide adequate structuring. The precise lower limit depends to some extent on the remainder of the composition; the skilled worker will know that the aim is to obtain a system in which the rheology exhibits a critical yield stress. To ensure adequate suspending duty it is preferred that the amount of pulped apple fibre is at least 0.2 wt%. The structured liquid is shear thinning. The preferred pouring viscosity being from 20 - 100 mPa.s and the yield stress or critical stress being about 0.3 Pa.
The composition may optionally comprise suspended solid material. The solid material may be microcapsules such as perfume encapsulates, or care additives in encapsulated form. It may alternatively, or additionally, take the form of insoluble ingredients such as silicones, quaternary ammonium materials, insoluble polymers, insoluble optical brighteners and other known benefit agents found, for example, in EP1328616 . For hard surface cleaners the solid material may be an abrasive. The amount of suspended solid material may be from 0.001 to up to 10 or even 20 wt%. A particular solid material to be suspended is a visual cue, for example the type of flat film cue described in EP13119706 . The cue may itself contain a segregated component of the composition. Because the cue must be water-soluble, yet insoluble in the composition, it is conveniently made from a modified polyvinyl alcohol that is insoluble in the presence of anionic surfactant. In that case, the detergent composition should comprise some anionic surfactant, preferably at least 5 wt% anionic surfactant.
According to a second aspect of the invention there is provided a process to manufacture a pulped apple fibre structured detergent liquid comprising at least 0.15 wt% pulped apple fibre structurant and at least 0.5 wt% surfactant, the process comprising the steps of:

a) selecting an apple fruit material;
b) forming apple fibres from the apple fruit material;
c) subjecting the apple fibres to mechanical processing comprising application of shear in the presence of at least 10 times the amount of water based on the apple fibres, the shear being sufficient to cause structural disruption and hydration of the apple fibres to form a structuring premix comprising dispersed pulped apple fibre;
d) further dispersing the pulped apple fibre structuring premix into a de-aerated detergent liquid to form an externally structured detergent liquid comprising surfactant; and
e) adding enzyme comprising cellulase and/ or pectate lyase to the externally structured detergent liquid.

Advantageously the detergent liquid in step (d) contains citrate builder.
Preferably, the liquid comprises 1 to 20 wt% hydrotropes. If the liquid is to be clear it desirably comprises no opacifier or pearliser. It may, however, comprise colorant.
The dispersal step (d) requires no addition of further dispersal aids to the premix formed in step (c). Advantageously a preservative is added to the premix during or after step (c), particularly if the premix will be stored for some time before addition to the detergent liquid.
The externally structured detergent liquid compositions comprising cellulase and /or pectate lyase are useful for a wide range of cleaning purposes, including laundry, machine and hand wash, hard surface cleaning, including machine and hand dish wash and other household cleaning applications, for example surface care including kitchen, bathroom and general purpose cleaning.
The externally structured liquid may advantageously be used as a liquid laundry detergent composition, concentrated or dilute, contained in bottle or unit dose formats, for example sachets, or hand dishwashing compositions. Other compositions that are used neat, including laundry liquids used for pre-treatment and hard surface cleaning compositions of the type that are applied from a spray or pump may also be structured with this external structurant as low levels of surfactant can be structured. The externally structured enzyme containing compositions are suitable for hand contact after dilution uses, such as hand dishwashing and hand laundry.
Laundry detergents are generally classified as low foam, used in automatic washing machines, and high foam, used in hand wash and top loading washing machines. The pulped apple fibre is suitable for both.

Detailed Description of the Invention

Pulped Apple fibre

When supplied in the form of a premix the level of pulped apple fibre in the premix preferably lies in the range 1 to 2.5 wt%. When added to a detergent liquid the amount of pulped apple fibre preferably lies in the range of 0.15 wt% to 0.7 wt%, more preferably 0.2 to 0.35 wt%.
A preferred grade of apple fibre is available under the name "Herbacel AQ plus apple fibre", ex Herba Foods. This apple fibre is supplied as a fine dried powder with low colour and has a high water binding capacity of >10 kg water per kg of powder.
Because the dispersed pulped apple fibre is biodegradable, it is advantageous to include a preservative into the premix. In any case, a preservative is normally needed in the liquid detergent composition.
The refining process may entail soaking the fibres in NaOH (<1%), draining and standing to soften, before shearing, refining and & drying. Dried materials may be relatively large > 100 micron. After milling a powdered apple fibre material is obtained. The refining process leaves much of the natural cell wall intact. The resulting highly swelling apple fibre materials are typically used as food additives.
The apple fibre as supplied does not contain polymeric or other dispersants that are commonly found at high levels in other external structurants including MFC. For example, CP Kelco MFC is a combination of fibre (60%) with other swelling polymers (40%), such as xanthan, to make it easier to disperse. For applications where skin is exposed to the liquid, for instance hand dish wash compositions, the absence of such polymers may avoid negative sensorial attributes such as sliminess or stickiness. The absence of any additional polymers or gums ensures the required rheology of the pulped apple fibre as an external structurant. It also makes this external structurant highly compatible with other polymers or thickeners that may be included into the composition. Especially soil release polymers, for example those designed to release dirt from polyester fabrics, and cleaning polymers, for example ethoxylated polyethylene imines, especially PEI 600 20 EO (EPEI): a polyethylene imine with a Mwt of the polymer backbone of approximately 600 and an average of 20 moles of ethylene oxide for each Nitrogen.
Before it can be used as an external structurant it is necessary to process the powdered apple fibre material as supplied to break it down to be more space filling. This is done by dispersing it at a low concentration into water under high shear conditions to form a structuring premix. A preservative may usefully be added at this stage. This high shear dispersal opens out the structure to increase the phase volume. The shear should not be so high as to lead to defibrillation. If a high-pressure homogeniser is used it should be operated between 200 and 600 bar. The more shear that is applied the less dense the resulting particles. Whilst the morphology is changed by the high shear, process aggregate size appears not to be changed. At high pressure, the fibres break down and then fill the water phase. The high shear also forms fibrils by rubbing loose the outer parts of the cell walls and these are able to form a matrix that structures the water outside of the volume of the original fibre.
As an alternative to a high pressure homogeniser the shear needed to form a pulped apple fibre structuring premix may alternatively be supplied by a high shear mixer, such as a Silverson. One possible process passes the premix through several sequential high-shear mixing stages in order to ensure full hydration and dispersal of the apple fibre to form the pulped apple fibre dispersion.
The premix can then simply be added to a partially, or formed detergent liquid premix with the surfactant and other components of the liquid detergent composition already admixed. Ingredients that would be held back at this stage are perfume, enzymes, including the cellulase and / or pectate lyase, and any insoluble particulate material that will be suspended by the external structurant. Such post-dosed materials are added later to the structured liquid, under low shear mixing conditions.
Dispersed as an external structurant in the liquid detergent product, pulped apple fibre has a distinctive appearance, which can reinforce the impression of a highly concentrated liquid without need to resort to suspended mica or other visual cues that add non-functional chemicals to the detergent liquid.
Pulped apple fibre benefits from air free processing as this improves the stability of the resulting liquids, especially to bottom clear layer separation. This has been demonstrated successfully for 35 ml (so called 3x) and 20 ml (so called 5x) dose liquids for European sized washing machines (typically 7 to10 litres fill). Microfibrous cellulose (MFC) has proved extremely difficult to process in a way that prevents bottom clear layer separation for the 20 ml dose liquids.
In order to obtain a satisfactory external structurant is it necessary to process the apple fibre into a premix and it is also important to apply shear to it more than would be needed just to get it dispersed. The additional energy is advantageous for disruption of the fibres and it may assist with the hydration. The structurant is typically dispersed at very high shear to break up the insoluble fibres and to increase phase volume of the structuring system by maximising break up and contact with anhydrous structuring material. The premix may be left to hydrate further (age) after the high shear mixing.
The concentration of pulped apple fibre in the premix depends on the ability of the equipment to deal with the higher viscosity due to higher concentrations. The minimum will preferably be at least 1 wt% for practical reasons.
The process gives a stable detergent product with sufficient critical stress, 0.3 Pa, to suspend insoluble particulate material and suspend itself to give minimal top clear layer separation.

Surfactant

In principle, the pulped apple fibre structurant will structure any type of surfactant containing detergent liquid. However, for cleaning purposes preferred surfactants assist in removing soil from the textile materials or from hard surfaces and assist in maintaining removed soil in solution or suspension in water. Thus, anionic and/or nonionic surfactants are preferred, more preferably provided in a calcium tolerant blend.
Linear alkyl benzene sulphonate (LAS) used on its own is generally calcium intolerant. When required, in order to ensure calcium tolerance, surfactant systems should generally avoid having levels of LAS above 90 wt%. Nonionic-free systems with 95 wt% LAS can be made if some zwitterionic surfactant, such as carbobetaine, is present. Generally it is preferred to use less than 90 wt% LAS and at least 10 wt% of nonionic surfactant. However, an advantage of the use of pulped apple fibre over HCO is that it is not necessary to have high levels of nonionic surfactant in the composition. HCO is often added to the mix from a solution in nonionic surfactant and this is therefore limiting for the composition. It is desirable to include only low levels of nonionic, or even to eliminate this component, from detergent compositions designed for high foaming applications. Thus, such compositions structured with pulped apple fibre, may comprise less than 2 wt%, preferably less than 1 wt%, even zero, nonionic surfactant.
Anionic surfactants include sulphates and sulphonates. Preferred alkyl ether sulphates are C₈-C₁₅ alkyl and have 1-10 moles of ethoxylation. Preferred sulphonates are alkylbenzene sulphonates, particularly linear alkylbenzene sulphonates having an alkyl chain length of C₈-C₁₅. The counter ion for anionic surfactants is generally an alkali metal, typically sodium, although other counterions such as MEA, TEA or ammonium can be used and may be preferred for concentrated liquids.
Nonionic surfactants include primary and secondary alcohol ethoxylates, especially C₈-C₂₀ aliphatic alcohol ethoxylated with an average of from 1 to 20 moles of ethylene oxide per mole of alcohol, and more especially the C₁₀-C₁₅ primary and secondary aliphatic alcohols ethoxylated with an average of from 1 to 10 moles of ethylene oxide per mole of alcohol. Non-ethoxylated nonionic surfactants include alkyl polyglycosides, glycerol monoethers and polyhydroxy amides (glucamide). Mixtures of nonionic surfactant may be used. When included therein the composition contains from 0.2 wt% to 40 wt%, preferably 1 wt% to 20 wt%, more preferably 5 to 15 wt% of a non-ionic surfactant, such as alcohol ethoxylate, nonylphenol ethoxylate, alkylpolyglycoside, alkyldimethylamineoxide, ethoxylated fatty acid monoethanolamide, fatty acid monoethanolamide, polyhydroxy alkyl fatty acid amide, or N-acyl N-alkyl derivatives of glucosamine ("glucamides").
Preferred nonionic surfactants that may be used include the primary and secondary alcohol ethoxylates, especially the C₈-C₂₀ aliphatic alcohols ethoxylated with an average of from 1 to 35 moles of ethylene oxide per mole of alcohol, and more especially the C₁₀-C₁₅ primary and secondary aliphatic alcohols ethoxylated with an average of from 1 to 10 moles of ethylene oxide per mole of alcohol.
The Calcium Tolerance Test used herein is that defined in EP1771543 . A surfactant blend is prepared at a concentration of 0.7 g/l in water containing sufficient calcium ions to give a French Hardness of 40 degrees. Other electrolytes such as sodium chloride, sodium sulphate, and sodium hydroxide are added as necessary to adjust the ionic strength to 0.5M and the pH to 10. The absorption of light of wavelength 540 nm through 4 mm of sample is measured 15 minutes after sample preparation. Ten measurements are made and an average value is calculated. Samples that give an absorption value of less than 0.08 are deemed calcium tolerant.

Water

The compositions are aqueous, that is to say that water forms the majority of the solvent system. Hydrotropes such as propylene glycol and glycerol/glycerine may be used but they will normally be present at a lesser amount than the water. The water level for an aqueous liquid is typically at least 10 wt%. In order to incorporate 0.15 wt% pulped apple fibre with 15 times its own weight water absorbed it is normal to have a minimum of 3 wt% water added with the pulped apple fibre (from the pre-mix). For the preferred level of about 0.25 wt% pulped apple fibre, the amount of water added from a 2.5 wt% premix is 9.75%. Additional water is needed in the composition in order to keep the surfactant, any polymers, soluble builders, enzymes etc in solution/ dispersion. The water amount stated includes both free and any bound water.

Optional suspended insoluble particulate material

The suspended material can be any type. This includes perfume encapsulates, care encapsulates and/ or visual cues or suspended particulate opacifier such as mica or other suspended pearlescent materials and mixtures of these materials. The closer the match of the density of the material to that of the liquid and the thicker the liquid before addition of the external structurant, the higher the amount of material that may be suspended. Typically, up to 5 wt% of insoluble particluate material may be suspended stably using the pulped apple fibre external structuring system, however amounts up to 20 wt% are possible.

Thickeners

Polymeric thickening systems may be added to the liquid to increase the viscosity and further modify the rheology. Pulped apple fibre is compatible with such thickening systems and it is compatible with other fibre based external structurants, particularly pulped citrus fibre.

Enzymes

In addition to the one or more essential enzymes, one or more further enzymes may be present in the detergent compositions. The essential enzymes are cellulases and/or pectate lyase. The further enzymes may be selected from the enzymes known to be compatible with surfactant containing compositions, and preferably comprise one or more of proteases, lipases, mannanases and amylases.

Cellulase:

Suitable cellulases include those of bacterial or fungal origin. Chemically modified or protein engineered mutants are included. Suitable cellulases include cellulases from the genera Bacillus, Pseudomonas, Humicola, Fusarium, Thielavia, Acremonium, e.g. the fungal cellulases produced from Humicola insolens, Thielavia terrestris, Myceliophthora thermophila, and Fusarium oxysporum disclosed in US 4,435,307 , US 5,648,263 , US 5,691,178 , US 5,776,757 , WO 89/09259 , WO 96/029397 , and WO 98/012307 . Commercially available cellulases include Celluzyme™, Carezyme™, Endolase™, Renozyme™ (Novozymes A/S), Clazinase™ and Puradax HA™ (Genencor International Inc.), and KAC-500(B)™ (Kao Corporation).

Pectate Lyase:

Examples of pectate lyases (also called polygalacturonate lyases) include pectate lyases that have been cloned from different bacterial genera such as Erwinia, Pseudomonas, Klebsiella and Xanthomonas, as well as from Bacillus subtilis (Nasser et al. (1993) FEBS Letts. 335:319-326) and Bacillus sp. YA-14 (Kim et al. (1994) Biosci. Biotech. Biochem. 58:947-949). Purification of pectate lyases with maximum activity in the pH range of 8-10 produced by Bacillus pumilus (Dave and Vaughn (1971) J. Bacteriol. 108:166-174), B. polymyxa (Nagel and Vaughn (1961) Arch. Biochem. Biophys. 93:344-352), B. stearothermophilus (Karbassi and Vaughn (1980) Can. J. Microbiol. 26:377-384), Bacillus sp. (Hasegawa and Nagel (1966) J. Food Sci. 31:838-845) and Bacillus sp. RK9 (Kelly and Fogarty (1978) Can. J. Microbiol. 24:1164-1172) have also been described. Any of the above, as well as divalent cation-independent and/or thermostable pectate lyases, may be used. The pectate lyase may preferably comprise the pectate lyase disclosed in Heffron et al., (1995) Mol. Plant-Microbe Interact. 8: 331-334 and Henrissat et al., (1995) Plant Physiol. 107: 963-976. Specifically contemplated pectate lyases are disclosed in WO 99/27083 and WO 99/27084 . Other specifically contemplated pectate lyases (derived from Bacillus licheniformis) are disclosed in US patent no. 6,284,524 . Specifically contemplated pectate lyase variants are disclosed in WO 02/006442 , especially the variants disclosed in the Examples in WO 02/006442 .
Examples of commercially available alkaline pectate lyases include BIOPREP™, SCOURZYME™ L and Xpect™ from Novozymes A/S, Denmark.

Protease:

Suitable proteases include those of animal, vegetable or microbial origin. Microbial origin is preferred. Chemically modified or protein engineered mutants are included. The protease may be a serine protease or a metallo protease, preferably an alkaline microbial protease or a trypsin-like protease. Preferred commercially available protease enzymes include Alcalase™, Savinase™, Primase™, Duralase™, Dyrazym™, Esperase™, Everlase™, Polarzyme™, and Kannase™, (Novozymes A/S), Maxatase™, Maxacal™, Maxapem™, Properase™, Purafect™, Purafect OxP™, FN2™, and FN3™ (Genencor International Inc.).

Lipase:

Suitable lipases include those of bacterial or fungal origin. Chemically modified or protein engineered mutants are included. Examples of useful lipases include lipases from Humicola (synonym Thermomyces), e.g. from H. lanuginosa (T. lanuginosus) as described in EP 258 068 and EP 305 216 or from H. insolens as described in WO 96/13580 , a Pseudomonas lipase, e.g. from P. alcaligenes or P. pseudoalcaligenes ( EP 218 272 ), P. cepacia ( EP 331 376 ), P. stutzeri ( GB 1,372,034 ), P. fluorescens, Pseudomonas sp. strain SD 705 ( WO 95/06720 and WO 96/27002 ), P. wisconsinensis ( WO 96/12012 ), a Bacillus lipase, e.g. from B. subtilis (Dartois et al. (1993), Biochemica et Biophysica Acta, 1131, 253-360), B. stearothermophilus ( JP 64/744992 ) or B. pumilus ( WO 91/16422 ). Preferred ones have a high degree of homology with the wild-type lipase derived from Humicola lanuginosa.
Other examples are lipase variants such as those described in WO 92/05249 , WO 94/01541 , EP 407 225 , EP 260 105 , WO 95/35381 , WO 96/00292 , WO 95/30744 , WO 94/25578 , WO 95/14783 , WO 95/22615 , WO 97/04079 and WO 97/07202 .
Preferred commercially available lipase enzymes include Lipolase™ and Lipolase Ultra™, Lipex™ and Lipoclean™ (Novozymes A/S). Also Lipomax™ a lyophilized lipase-preparation from pseudomonas alcaligenes (originally from Gist-brocades, more recently from the Genencor division of Danisco).
Lipase is preferably included in an amount of from 0.001 to 0.3 wt% active enzyme.
Advantageously, the presence of relatively high levels of calcium in poorly built or unbuilt wash liquors has a beneficial effect on the turnover of certain enzymes, particularly lipase enzymes and preferably lipases from Humicola.
The preferred lipases include first wash lipases which comprise a polypeptide having an amino acid sequence which has at least 90% sequence identity with the wild-type lipase derived from Humicola lanuginosa strain DSM 4109 and compared to said wild-type lipase, comprises a substitution of an electrically neutral or negatively charged amino acid within 15 A of E1 or Q249 with a positively charged amino acid; and may further comprise:

(I) a peptide addition at the C-terminal;
(II) a peptide addition at the N-terminal;
(III) meets the following limitations:
1. i. comprises a negatively charged amino acid in position E210 of said wild-type lipase;
2. ii. comprises a negatively charged amino acid in the region corresponding to positions 90-101 of said wild-type lipase; and
3. iii. comprises a neutral or negatively charged amino acid at a position corresponding to N94 of said wild-type lipase; and/or
4. iv. has a negative charge or neutral charge in the region corresponding to positions 90-101 of said wild-type lipase; and
(IV) mixtures thereof.

These are available under the Lipex™ brand from Novozymes. A similar enzyme from Novozymes, but believed to fall outside of the above definition, is made available by Novozymes under the name Lipoclean™ and this is also preferred.

Phospholipase:

Phospholipase may be classified as EC 3.1.1.4 and/or EC 3.1.1.32. As used herein, the term phospholipase is an enzyme that has activity towards phospholipids. Phospholipids, such as lecithin or phosphatidylcholine, consist of glycerol esterified with two fatty acids in an outer (sn-1) and the middle (sn-2) positions and esterified with phosphoric acid in the third position; the phosphoric acid, in turn, may be esterified to an amino-alcohol. Phospholipases are enzymes that participate in the hydrolysis of phospholipids. Several types of phospholipase activity can be distinguished, including phospholipases A₁ and A₂ which hydrolyze one fatty acyl group (in the sn-1 and sn-2 position, respectively) to form lysophospholipid; and lysophospholipase (or phospholipase B) which can hydrolyze the remaining fatty acyl group in lysophospholipid. Phospholipase C and phospholipase D (phosphodiesterases) release diacyl glycerol or phosphatidic acid respectively.

Cutinase:

Cutinase is classified in EC 3.1.1.74. The cutinase may be of any origin. Preferably cutinases are of microbial origin, in particular of bacterial, of fungal or of yeast origin.

Amylase:

Suitable amylases (alpha and/or beta) include those of bacterial or fungal origin. Chemically modified or protein engineered mutants are included. Amylases include, for example, alpha-amylases obtained from Bacillus, e.g. a special strain of B. licheniformis, described in more detail in GB 1,296,839 , or the Bacillus sp. strains disclosed in WO 95/026397 or WO 00/060060 . Commercially available amylases are Duramyl™, Termamyl™, Termamyl Ultra™, Natalase™, Stainzyme™, Fungamyl™ and BAN™ (Novozymes A/S), Rapidase™ and Purastar™ (from Genencor International Inc.).

Peroxidase/oxidase:

Suitable peroxidases/oxidases include those of plant, bacterial or fungal origin. Chemically modified or protein engineered mutants are included. Examples of useful peroxidases include peroxidases from Coprinus, e.g. from C. cinereus, and variants thereof as those described in WO 93/24618 , WO 95/10602 , and WO 98/15257 . Commercially available peroxidases include Guardzyme™ and Novozym™ 51004 (Novozymes A/S).

Mannanase:

Examples of mannanases (EC 3.2.1.78) include mannanases of bacterial and fungal origin. The mannanase may be derived from a strain of the filamentous fungus genus Aspergillus, preferably Aspergillus niger or Aspergillus aculeatus ( WO 94/25576 ). WO 93/24622 discloses a mannanase isolated from Trichoderma reseei. Mannanases have also been isolated from several bacteria, including Bacillus organisms. For example, Talbot et al., Appl. Environ. Microbiol., Vol.56, No. 11, pp. 3505-3510 (1990) describes a beta-mannanase derived from Bacillus stearothermophilus. Mendoza et al., World J. Microbiol. Biotech., Vol. 10, No. 5, pp. 551-555 (1994) describes a beta-mannanase derived from Bacillus subtilis. JP-A-03047076 discloses a beta-mannanase derived from Bacillus sp. JP-A-63056289 describes the production of an alkaline, thermostable beta-mannanase. JP-A-63036775 relates to the Bacillus microorganism FERM P-8856 which produces beta-mannanase and beta-mannosidase. JP-A-08051975 discloses alkaline beta-mannanases from alkalophilic Bacillus sp. AM-001. A purified mannanase from Bacillus amyloliquefaciens is disclosed in WO 97/11164 . WO 91/18974 describes a hemicellulase such as a glucanase, xylanase or mannanase active. Contemplated are the alkaline family 5 and 26 mannanases derived from Bacillus agaradhaerens, Bacillus licheniformis, Bacillus halodurans, Bacillus clausii, Bacillus sp., and Humicola insolens disclosed in WO 99/64619 . Especially contemplated are the Bacillus sp. mannanases used in the Examples of WO 99/64619 .
Examples of commercially available mannanases include Mannaway™ available from Novozymes A/S Denmark.
Enzyme present in the composition may be stabilized using conventional stabilizing agents, e.g., a polyol such as propylene glycol or glycerol, a sugar or sugar alcohol, lactic acid, boric acid, or a boric acid derivative, e.g., an aromatic borate ester, or a phenyl boronic acid derivative such as 4-formylphenyl boronic acid, and the composition may be formulated as described in e.g. WO 92/19709 and WO 92/19708 .

Polymers

Although optional, it is desirable to include soluble polymers in the compositions of the invention. A preferred polymer is modified polyethylene imine PEI 600(20EO). Soil release polymers, especially polyester soil release polymers may also be used. The amount of polymers, when used, is preferably greater than 2 wt%, more preferably greater than 5 wt%, even greater than 10 wt%. Anti-redeposition polymers, for example sodium carboxymethyl cellulose, may additionally be used.

Sequestrants

Although optional, it is desirable to include water-soluble sequestrants in the compositions of the invention. Phosphonate sequestrants are preferred. When included they are advantageously used at levels of from 0.3 to 3 wt%. A preferred sequestrant is HEDP (1-Hydroxyethylidene -1,1,-diphosphonic acid), available as DEQUEST® 2010 from Thermphos. It should be noted that any sequestrant that comes out of solution under storage conditions is kept suspended and dispersed by the external structurant. A similar point may be made about soil release polymers and any other ingredients that are used near to or over the limit of their solubility.

Builders

Water-soluble builders may be included in the compositions of the invention. The presence of residual acid in the apple fibre may have compatibility with citric acid or citrate based builders. The external structurant may be used to suspend low levels of insoluble builders. The use of a Calcium tolerant surfactant system lowers the need for builder to be included in the compositions. When present builder may be used at a level of up to 5 wt%, preferably up to 3 wt%.

Hydrotropes/neutralising agents

As mentioned above the compositions are aqueous but the need to keep high levels of surfactants and other water-soluble ingredients in solution may necessitate the presence of additional solvents or hydrotropes. Preferred hydrotropes are propylene glycol, glycerol, glycerine and mixtures thereof. Hydrotropes, when used, are preferably present at levels of from 1 to 20 wt%.

pH adjustment

The composition may further comprise MEA and / or TEA and/ or sodium hydroxide for alkalinity (neutralisation and buffering). As mentioned above it may comprise citric acid. Levels of citric acid preferably range from 0.5 to 5 wt%

Optical brighteners

Soluble fabric whitening agents may be included. The use of the external structurant also makes it possible to use insoluble OBA but this is less preferred if it is desired that the liquid is clear (i.e. that it is possible to see through it).

Preservative

Due to the apple pulp fibre being a plant material it is liable to attack from any living organisms in the composition. It is thus desirable to include a preservative in the composition, especially if it is formulated to have a near neutral pH which will allow microbes and other organisms to survive and grow. Proxel GXL™ antimicrobial preservative, a 20% solution of 1,2 benzisothiazolin-3-one in dipropylene glycol and water from Arch Chemicals is a preferred preservative for the liquid compositions. Potassium Sorbate may alternatively or additionally be used.

EXAMPLES

The invention will now be further described with reference to the following nonlimiting examples. In the examples, these abbreviations are used:

AF: is Herbacel AQ plus™ apple fibre, a powdered apple fruit material ex Herbafoods.
AFC: is Herbacel classic apple fibre, a low water absorbancy powdered apple fruit material ex Herbafoods.
CF: is Herbacel AQ plus™ citrus fibre, ex Herbafoods.
MFC: is Microfibrous cellulose ex CP Kelco.
LAS: is sodium linear alkyl benzene sulphonate anionic surfactant.
LAS acid: is acid form of LAS.
SLES: is Sodium Lauryl Ether Sulphate with average of 3EO.
NI 7EO: is alcohol ethoxylate 7EO (Neodol 25-7 ex Shell Chemicals).
Empigen® BB: is an alkyl betaine ex Huntsman.
Prifac® 5908: is saturated lauric fatty acid ex Croda.
Proxel® GXL: is antimicrobial preservative, a 20% solution of 1,2 benzisothiazolin-3-one in dipropylene glycol and water ex Arch Biocides.
MPG: is mono propylene glycol.
TEA: is Triethanolamine.
NaOH: is 47% sodium hydroxide.
Carezyme®: is a cellulase ex Novozymes.
Endolase®: is Endolase 5000L, an endocellulase promoted for its whitening benefits ex Novozymes.
Renozyme®: is a cellulase ex Novozymes.
Xpect® 1000L: is a pectate lyase ex Novozymes.
EPEI: is ethoxylated polyethylene imine cleaning polymer PEI 600 20EO ex BASF.
SRP: is Texcare® SRN170 polyester soil release polymer ex Clariant.
Perfume: is free oil perfume.

Example 1 and comparative examples A and B - Premixes

Three premixes were prepared using high intensity high shear mixing. All the premixes were sheared and dispersed using a Silverson mixer. The preservative added was Proxel® GXL.
AFC (Classic Apple) has a low water binding capacity of less than 10 kg/kg whereas both AF (Apple AQ+) and CF (Citrus AQ+) have water binding capacities in excess of that value and their capacity is further increased by the application of high shear during the preparation of the premixes. Table 1 - Premix compositions

Wt% as supplied 1 A B

Structurant type Apple (AF) Apple (AFC) Citrus (CF)

Structurant amount 2.00 2.00 2.00

Demin. Water 97.92 97.92 97.92

Preservative 0.08 0.08 0.08
The Classic Apple failed to produce a stable premix and so could not be used for structuring. The others each provided a satisfactory homogeneous premix suitable for use as an external structurant in an aqueous detergent liquid.

Example 2 and comparative examples D and E

The premixes from Example 1 and comparative examples A and B were dispersed into a concentrated aqueous laundry detergent liquid base to form the structured liquids specified in table 2.

Table 2 - Composition of Detergent liquid base

Material	Active	As 100%
Demin water	100.00	To 100
Proxel® GXL*	20.00	0.016
MPG	100.00	20.00
NaOH	47.00	0.25
TEA	100.00	3.50
NI 7EO	100.00	12.74
LAS Acid	97.10	8.49
SLES	70.00	4.24
Empigen® BB	30.00	1.50
Prifac® 5908	100.00	1.50
EPEI	80.00	5.50
SRP	70.00	3.75
Perfume	100.00	2.43
Structurant**	2.00	0.25
Enzyme	See below	See below

*Proxel is added both to the base and the activated apple fibre premix. It is present in both at a level of 0.08 wt%, as received. The 100% active level is 0.016 wt% due to it being a 20 wt% solution.
"The premix made in Example 1 or D.

The concentrated base detergent mixture in Table 1 was circulated via a 150/250 Silverson L4R high shear mill by means of a recycle loop to ensure all lines were fully primed and purged of air. Flow rate 1450 l/hr (single pass residence time in mill 0.1 seconds). The Silverson mill was turned on at 6250 rpm (9063 w/kg) to simulate large scale operating conditions. Then the structurant premix from Example 1 was dosed into the main recirculation loop close to the high shear mixer inlet to minimise interaction between the streams prior to intimate dispersion. The perfume was then added using low shear mixing. Care was taken to avoid aeration during mixing.
The process was repeated using premix B to form structured liquid D. We attempted to use premix C to form structured liquid E, but due to the poor quality of the premix C this Classic Apple premix could not be used to provide a structured liquid.
Structured liquids 2 and D, without any added enzyme, were immediately sampled and their rheology measured. After storage at 37°C the rheology of the structured liquids was again measured and compared with the initial rheology of the same liquid. The required rheology for thickening and suspending duty was obtained and maintained and no separation was observed for Example 2 (the high water absorbency apple fibre pulp and comparative example D (the high water absorbency citrus fibre pulp). Rheology was measured using an AR2000 rheometer from TA Instruments using a 2°/4cm cone/plate.

Example 3 - Addition of enzymes and long term effect on rheology

Cellulases are known to be sufficiently aggressive to remove cotton pills. Pectate lyase will attack pectin in an apple pulp mixture.
Eight new samples were made up based on Example 2 and Example D, but with part of the water replaced by the following four types and amounts of enzymes which were dispersed into the modified liquids using a rod. Processing up until addition of the enzymes was done as for Examples 2 and D. The level of inclusion of each of the enzymes was chosen to be that suitable for effective performance when delivered from the 20 ml concentrated laundry detergent base.
0.5 wt% Endolase 5000L (cellulase)
0.5 wt% Renozyme (cellulase)
2.4 wt% Xpect 1000L (pectate lyase)
0.5 wt% Carezyme (cellulase)
The rheology of each of the enzyme containing liquids was measured in the same way as for Examples 2 and D; initially and after 6 months storage at 37°C. No significant change between the initial and 6 month rheology was taken as evidence that the external structuring system was not attacked by the particular enzyme.
Example 2. No significant difference was detected between the rheology of any of the four enzyme containing Apple fibre structured samples and the control, either initially or after 6 months storage at 37°C. This was something of a surprise for the pectate lyase as it could be assumed to have attacked the pectin content of the apple structuring system. Without wishing to be bound by theory it seems that the initial pectin content does not contribute to the structuring.
Example D. No systematic change was observed after 6 months storage at 37°C with either cellulases or pectate lyase. Some evidence that without enzymes there is a small drop in suspending ability for the Example D control on storage at 37°C. There was no sign of this for the Example 2 control.
From previous work we had observed an effect on the low shear viscosity behaviour of a concentrated liquid containing Carezyme® when externally structured using 0.1 wt% MFC. After storage at 37 °C we observed an initial drop in low shear viscosity which was thought to have been caused by the cellulase attacking part of the MFC external structurant, but not causing it to fail totally. Nevertheless any attack on the structuring system is undesirable as it could seriously affect the suspending ability of the structurant.
Pectate Lyase and cellulases have been shown to have no significant effect on the rheological profile of aqueous detergent liquids structured with high water absorbency apple fibres or high water absorbency citrus fibres.
The required rheology is usefully obtained and maintained in the presence of high levels of cleaning and soil release polymers.

Claims

A structured aqueous liquid detergent composition comprising:
at least 10 wt% water,

at least 0.5 wt% surfactant,

at least 0.0001 wt% of cellulase and /or pectate lyase

an external structurant,
characterised in that the external structurant comprises at least 0.15 wt%, preferably at least 0.2%, apple fibre that has been mechanically pulped and swollen in water to an extent that it can absorb at least 10 times its own dry weight of water.
A composition according to claim 1 comprising 0.16 to 0.35 wt% pulped apple fibre.
A composition according to any preceding claim with a yield stress greater than 0.2 Pa.
A composition according to any preceding claim in which the enzyme comprises 0.001 to 0.3 wt% active enzyme.
A composition according to any preceding claim further comprising suspended insoluble material.
A composition according to any preceding claim comprising at least 1.5 wt%, preferably at least 2.5 wt% water-soluble polymers.
A composition according to claim 6 in which the polymers are selected from the group consisting of modified ethoxylated polyethylene imines, polyester soil release polymers and mixtures thereof.
A composition according to any preceding claim comprising at least 2.5 wt % anionic surfactant.
A composition according to claim 8 comprising at least 10 wt% anionic surfactant.
A composition according to any preceding claim comprising at least 3 wt% nonionic surfactant.
A high foaming composition according to any one of claims 1 to 10 comprising at most 2 wt% nonionic surfactant.
A composition according to any preceding claim comprising at least 25 wt% total detergent surfactant.
A process to manufacture a pulped apple fibre structured detergent liquid according to any preceding claim comprising at least 0.15 wt% pulped apple fibre structurant and at least 0.5 wt% surfactant, the process comprising the steps of:
a) selecting an apple fruit material, preferably one with low sugar content,

b) forming apple fibres from the apple fruit material, preferably by extraction,

c) subjecting the apple fibres to mechanical processing comprising application of shear in the presence of at least 15 times the amount of water based on the apple fibres, the shear being sufficient to cause structural disruption and hydration of the apple fibres to form a structuring premix comprising dispersed pulped apple fibre; and

d) further dispersing the pulped apple fibre structuring premix into a de-aerated detergent liquid to form an externally structured detergent liquid comprising surfactant; and

e) adding enzymes comprising cellulase and/or pectate lyase to the externally structured detergent liquid.