The present invention relates to a detergent composition and to a process for adding Benefit Agents during the wash, in particular the invention relates to detergent compositions containing a new form of deposition system based on agents with a high affinity for a fabric.

It is well known and well documented in the relevant technical and patent literature that fibrous materials such as fabrics or the like can be treated with Benefit Agents which deliver one or more desirable properties to the material.

Conventionally these treatments are carried out by applying to the surface of the material a composition containing one or more active ingredients which serve to impart the benefit or benefits which are wanted.

The application of such conventional Benefit Agents compositions to achieve the desired results relies essentially on two key factors: firstly, it is important that the active ingredient or ingredients with which the substrate is to be treated are provided in a form of composition which on the one hand is stable upon storage and maintains the essential Benefit Agent or aids in active form, and on the other hand allows the active(s) to be deposited from the composition onto the substrate surface; secondly, it is essential that once deposited the Benefit Agent or aids are retained on the substrate surface, so that when the treatment is completed and for example the substrate is rinsed to remove unwanted excess composition or residual components thereof, sufficient of the Benefit Agent remains attached to the substrate surface so as to impart the intended characteristic benefit or benefits thereto.

This attachment of active material to the treated substrate surface is generally of the nature of physisorption; that is to say, the Benefit Agents are adsorbed onto the surface of the substrate by virtue of physical intermolecular forces such as hydrogen bonding. Conventionally, it has been accepted that this form of retention of active substrates on treated substrate surfaces gives adequate results as regards achievable benefits and economics.

However, the deposition of Benefit Agents in such a manner is poor and there is a need to improve the efficiency of the deposition. There is also a need to ensure that the Benefit Agents, remain on the fabric or fibre during additional steps such as rinsing and during wear.

The present application has derived a way of overcoming this problem of depositing Benefit Agents onto fabrics, and ensuring that they remain on the fabric during wear.

Accordingly the present application relates to a detergent composition comprising a surfactant, a peptide or protein Deposition Aid having a high affinity for fibres or a surface and a Benefit Agent attached/adsorbed to the peptide or protein Deposition Aid, wherein said Benefit Agent is selected from a perfume, an encapsulated perfume, a photo protective agent, a soil release polymer, a soil repelling agent, a fabric softening compound selected from clay, cationic active or silicone, an insecticide, a fungicide, antioxidants or dye fix actives.

The peptide/protein Deposition Aid is any cellulase or the binding domain thereof that has a high affinity for fibres or a surface.

A Benefit Agent in the context of this invention is a compound which gives a desirable effect on a fibre, fabric or surface.

It is especially preferred if the benefit agent gives a perceivable benefit to the fabric.

The present invention is of particular use when the composition is used in laundering fabrics and in this context a Benefit Agent is an agent which effects the feel, appearance, or the perception of a fabric. The Benefit Agent is a fabric softening compound, a perfume, an encapsulated perfume, a photo protective agent (such as a sunscreen), a dye fix active, an antioxidant, an insecticide, a soil repelling agent, a soil release polymer or a fungicide.

If the Benefit Agent is a fabric softening agent it comprises a clay, a cationic active, or silicone.

Suitable clays include a three layered smectite clay, preferably having a cation exchange capacity as described in GB1400898 (Procter and Gamble). Especially preferred are clays which are 2:1 layer phyllosilicates possessing a lattice charge deficiency in the range of 0.2 to 0.4g equivalents per half unit cell as described in EP 0 350 288 (Unilever).

Suitable cationic softening agents include quaternary ammonium softening compounds having a solubility in water at pH 2.5 and 20°C of less than 10g/l.

It is particularly advantageous if the cationic softening compound is a quaternary ammonium compound in which at least one long chain alkyl group is connected to the quaternary ammonium group via at least one ester link. Suitable cationic softeners are described in US 4 137 180 (Naik) and WO 93/23510 (P&G).

The Benefit Agent may be a soil release polymer, suitable soil release polymers include polyesters of terephthalic acid and other aromatic dicarboxylic acids. Soil release polymers that may be used with the present invention which are the condensation products of aromatic dicarboxylic acids and dihydric alcohols include EP 185 427A, EP 241 984A, EP 241 985A and EP 272 033A (Procter & Gamble). Particularly preferred are the so called PET/POET (polyethylene terephthalate/polyoxyethylene terephthalate) and PET/PEG (Polyethylene terephthalate/ polyethylene glycol) which are disclosed in US 3 557 039 (ICI), GB 1 467 098 and EP 1 305A (Procter & Gamble). Polymers of this type are available commercially, for example, as Permalose, Aquaperle and Milease (Trade Marks, ICI) and Repel-O-Tex SRP3 (Trade Mark, Rhône-Poulenc). Sulphonated non-end-capped polyester of terephthalic acid, isophthalic acid, sulphoisophthalic acid and ethylene glycol as described in PCT/FR95/00658 (Rhône-Poulenc), published 1 December 1995 and sold commercially as Gerol (Trade mark Rhône-Poulenc) are also advantageous when used in conjunction with the present invention.

The Benefit Agent may be encapsulated. Suitable encapsulating materials include starches and poly(vinylacetate) and urea/formaldehyde condensate based materials.

Suitable materials that may be encapsulated include perfumes, insect repellents, fungicides, or photo protective agents.

The Benefit Agent is attached/adsorbed to the peptide/protein Deposition Aid. If the Benefit Agent is adsorbed this is preferably by simple physisorption of the enzyme.

If the benefit is attached to the peptide/protein Deposition Aid this is preferably via a linking agent.

Suitable linking agents are molecules which show a high affinity for the Benefit Agent. It is preferred if the linking agent is covalently attached to the peptide/protein Deposition Aid, it is also advantageous if the linking agent is covalently bound to the Benefit Agent.

Preferred linking agents are selected from 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, N-ethyl-5-phenylisoxazolium - 3 - sulphonate, 1 - cyclohexyl-3-(2 morpholinoethyl) carbodide metho-p-tolune sulphonate, N-ethoxycarbonyl-2-ethoxy 1,2 dihydroquinoline or glutaraldehyde.

The detergent compositions of the invention will contain a surfactant which may be chosen from soap and non-soap anionic, cationic, nonionic, amphoteric and zwitterionic detergent-active compounds, and mixtures thereof. Many suitable detergent-active compounds are available and are fully described in the literature, for example, in "Surface-Active Agents and Detergents", Volumes I and II, by Schwartz, Perry and Berch.

The preferred detergent-active compounds that can be used are soaps and synthetic non-soap anionic and nonionic compounds.

The detergent compositions of the invention may contain anionic surfactants. Suitable anionic surfactants are well-known to those skilled in the art. Examples include primary and secondary alkyl sulphates, particularly C₈-C₁₅ primary alkyl sulphates; alkyl benzene sulphonates, alkyl ether sulphates; olefin sulphonates; alkyl xylene sulphonates; dialkyl sulphosuccinates; and fatty acid ester sulphonates, alkyl ether carboxylates, alkyl sarccosinates. Sodium salts are generally preferred.

The compositions of the invention may also contain nonionic surfactant.

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 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 alkylpolyglycosides, glycerol monoethers, and polyhydroxyamides (glucamide).

The choice of surfactant and the amount present, will depend on the intended use of the detergent composition. In fabric washing compositions, different surfactant systems may be chosen, as is well known to the skilled formulator, for handwashing products and for products intended for use in different types of washing machine.

The total amount of surfactant present will also depend on the intended end use and may be as high as 60 wt%, for example, in a composition for washing fabrics by hand. In compositions for machine washing of fabrics, an amount of from 5 to 40 wt% is generally appropriate.

Detergent compositions suitable for use in most automatic fabric washing machines generally contain anionic non-soap surfactant, or nonionic surfactant, or combinations of the two in any ratio, optionally together with soap.

The detergent compositions of the invention will generally also contain one or more detergency builders. The total amount of detergency builder in the compositions will suitably range from 5 to 80 wt%, preferably from 10 to 60 wt%.

Inorganic builders that may be present include sodium carbonate, if desired in combination with a crystallisation seed for calcium carbonate, as disclosed in GB 1 437 950 (Unilever); crystalline and amorphous aluminosilicates, for example, zeolites as disclosed in GB 1 473 201 (Henkel), amorphous aluminosilicates as disclosed in GB 1 473 202 (Henkel) and mixed crystalline/amorphous aluminosilicates as disclosed in GB 1 470 250 (Procter & Gamble); and layered silicates as disclosed in EP 164 514B (Hoechst). Inorganic phosphate builders, for example, sodium orthophosphate, pyrophosphace and tripolyphosphate are also suitable for use with this invention.

The detergent compositions of the invention preferably contain an alkali metal, preferably sodium, aluminosilicate builder. Sodium aluminosilicates may generally be incorporated in amounts of from 10 to 70% by weight (anhydrous basis), preferably from 25 to 50 wt%.

The alkali metal aluminosilicate may be either crystalline or amorphous or mixtures thereof, having the general formula:

        0.8-1.5 Na₂O. Al₂O₃. 0.8-6 SiO₂

These materials contain some bound water and are required to have a calcium ion exchange capacity of at least 50 mg CaO/g. The preferred sodium aluminosilicates contain 1.5-3.5 SiO₂ units (in the formula above). Both the amorphous and the crystalline materials can be prepared readily by reaction between sodium silicate and sodium aluminate, as amply described in the literature.

Suitable crystalline sodium aluminosilicate ion-exchange detergency builders are described, for example, in GB 1 429 143 (Procter & Gamble). The preferred sodium aluminosilicates of this type are the well-known commercially available zeolites A and X, and mixtures thereof.

The zeolite may be the commercially available zeolite 4A now widely used in laundry detergent powders. However, according to a preferred embodiment of the invention, the zeolite builder incorporated in the compositions of the invention is maximum aluminium zeolite P (zeolite MAP) as described and claimed in EP 384 070A (Unilever). Zeolite MAP is defined as an alkali metal aluminosilicate of the zeolite P type having a silicon to aluminium ratio not exceeding 1.33, preferably within the range of from 0.90 to 1.33, and more preferably within the range of from 0.90 to 1.20.

Especially preferred is zeolite MAP having a silicon to aluminium ratio not exceeding 1.07, more preferably about 1.00. The calcium binding capacity of zeolite MAP is generally at least 150 mg CaO per g of anhydrous material.

Organic builders that may be present include polycarboxylate polymers such as polyacrylates, acrylic/maleic copolymers, and acrylic phosphinates; monomeric polycarboxylates such as citrates, gluconates, oxydisuccinates, glycerol mono-, di-and trisuccinates, carboxymethyloxysuccinates, carboxymethyloxymalonates, dipicolinates, hydroxyethyliminodiacetates, alkyl- and alkenylmalonates and succinates; and sulphonated fatty acid salts. This list is not intended to be exhaustive.

Especially preferred organic builders are citrates, suitably used in amounts of from 5 to 30 wt%, preferably from 10 to 25 wt%; and acrylic polymers, more especially acrylic/maleic copolymers, suitably used in amounts of from 0.5 to 15 wt%, preferably from 1 to 10 wt%.

Builders, both inorganic and organic, are preferably present in alkali metal salt, especially sodium salt, form.

Detergent compositions according to the invention may also suitably contain a bleach system. Fabric washing compositions may desirably contain peroxy bleach compounds, for example, inorganic persalts or organic peroxyacids, capable of yielding hydrogen peroxide in aqueous solution.

Suitable peroxy bleach compounds include organic peroxides such as urea peroxide, and inorganic persalts such as the alkali metal perborates, percarbonates, perphosphates, persilicates and persulphates. Preferred inorganic persalts are sodium perborate monohydrate and tetrahydrate, and sodium percarbonate.

Especially preferred is sodium percarbonate having a protective coating against destabilisation by moisture. Sodium percarbonate having a protective coating comprising sodium metaborate and sodium silicate is disclosed in GB 2 123 044B (Kao).

The peroxy bleach compound is suitably present in an amount of from 0.1 to 35 wt%, preferably from 0.5 to 25 wt%.

The peroxy bleach compound may be used in conjunction with a bleach activator (bleach precursor) to improve bleaching action at low wash temperatures. The bleach precursor is suitably present in an amount of from 0.1 to 8 wt%, preferably from 0.5 to 5 wt%.

Preferred bleach precursors are peroxycarboxylic acid precursors, more especially peracetic acid precursors and pernonanoic acid precursors. An especially preferred bleach precursor suitable for use in the present invention is N,N,N',N'-tetracetyl ethylenediamine (TAED) and sodium nonanoyloxybenzene sulphonate (SNOBS). The novel quaternary ammonium and phosphonium bleach precursors disclosed in US 4 751 015 and US 4 818 426 (Lever Brothers Company) and EP 402 971A (Unilever) are also of great interest. The cationic bleach precursors disclosed in EP 284 292A and EP 303 520A (Kao) may also be used.

The bleach system can be either supplemented with or replaced by a peroxyacid. Examples of such peracids can be found in US 4 686 063 and US 5 397 501 (patent on TPCAP - Unilever). A preferred example is the imido peroxycarboxylic class of peracids described in EP A 325 288, EP A 349 940, DE 382 3172 and EP 325 289. A particularly preferred example is phtalimido peroxy caproic acid (PAP). Such peracids are suitably present at 0.1 - 12%, preferably 0.5 - 10%.

A bleach stabiliser (heavy metal sequestrant) may also be present. Suitable bleach stabilisers include ethylenediamine tetraacetate (EDTA), the polyphosphonates such as Dequest (Trade Mark) and non-phosphate stabilisers such as EDDS (ethylene diamine di-succinic acid). These Bleach stabilisers are also useful for stain removal, especially in products containing low levels of bleaching species or no bleaching species.

An especially preferred bleach system comprises a peroxy bleach compound (preferably sodium percarbonate optionally together with a bleach activator), and a transition metal bleach catalyst as described and claimed in EP 458 397A, EP 458 398A and EP 509 787A (Unilever).

Suitable enzymes which may be used with the peptide/protein Deposition Aid of this invention include the proteases, amylases, cellulases, oxidases, peroxidases, lipolases and lipases cutinases and ceratinases usable for incorporation in detergent compositions.

Preferred proteolytic enzymes (proteases) are, catalytically active protein materials which degrade or alter protein types of stains when present as in fabric stains in a hydrolysis reaction. They may be of any suitable origin, such as vegetable, animal, bacterial or yeast origin.

Proteolytic enzymes or proteases of various qualities and origins and having activity in various pH ranges of from 4-12 are available and can be used in the instant invention. Examples of suitable proteolytic enzymes are the subtilisins, which are obtained from particular strains of B. subtilis and B. licheniformis, such as the commercially available subtilisins Maxatase (Trade Mark), as supplied by Gist Brocades N.V., Delft, Holland, and Alcalase (Trade Mark), as supplied by Novo Industri A/S, Copenhagen, Denmark.

Particularly suitable is a protease obtained from a strain of Bacillus having maximum activity throughout the pH range of 8-12, being commercially available, e.g. from Novo Induscri A/S under the registered trade-names Esperase (Trade Mark) and Savinase (Trade-Mark). The preparation of these and analogous enzymes is described in GB 1 243 785. Other commercial proteases are Kazusase (Trade Mark) (obtainable from Showa-Denko of Japan), Optimase (Trade Mark) (from Miles Kali-Chemie, Hannover, West Germany), and Superase (Trade Mark) (obtainable from Pfizer of U.S.A.).

Detergency enzymes are commonly employed in granular form in amounts of from about 0.1 to about 3.0 wt%.

The compositions of the invention may contain alkali metal, preferably sodium, carbonate, in order to increase detergency and ease processing. Sodium carbonate may suitably be present in amounts ranging from 1 to 60 wt%, preferably from 2 to 40 wt%. However, compositions containing little or no sodium carbonate are also within the scope of the invention.

Powder flow may be improved by the incorporation of a small amount of a powder structurant, for example, a fatty acid (or fatty acid soap), a sugar, an acrylate or acrylate/maleate polymer, or sodium silicate.

One preferred powder structurant is fatty acid soap, suitably present in an amount of from 1 to 5 wt%.

Other materials that may be present in detergent compositions of the invention include sodium silicate; antiredeposition agents such as cellulosic polymers; inorganic salts such as sodium sulphate; lather control agents or lather boosters as appropriate; proteolytic and lipolytic enzymes; dyes; coloured speckles; perfumes; foam controllers; fabric softening compounds, soil release polymers, fluorescers and decoupling polymers. This list is not intended to be exhaustive.

The detergent composition when diluted in the wash liquor (during a typical wash cycle) will give a pH of the wash liquor from 7 to 10.5.

The detergent components of the present invention may be incorporated in detergent compositions of all physical types, for example, powders, liquids, gels and solid bars.

Detergent compositions of the invention may be prepared by any suitable method.

Particulate detergent compositions are suitably prepared by spray-drying a slurry of compatible heat-insensitive ingredients, and then spraying on or postdosing those ingredients unsuitable for processing via the slurry. The skilled detergent formulator will have no difficulty in deciding which ingredients should be included in the slurry and which should not.

Particulate detergent compositions of the invention preferably have a bulk density of at least 400 g/l, more preferably at least 500 g/l.

Especially preferred compositions have bulk densities of at least 650 g/litre, more preferably at least 700 g/litre.

Such powders may be prepared either by post-tower densification of spray-dried powder, or by wholly non-tower methods such as dry mixing and granulation; in both cases a high-speed mixer/granulator may advantageously be used.

Processes using high-speed mixer/granulators are disclosed, for example, in EP 340 013A, EP 367 339A, EP 390 251A and EP 420 317A (Unilever).

Liquid detergent compositions can be prepared by admixing the essential and optional ingredients thereof in any desired order to provide compositions containing components in the requisite concentrations. Liquid compositions according to the present invention can also be in compact form which means it will contain a lower level of water compared to a conventional liquid detergent.

The invention will now be illustrated by with reference to the following examples.

Particles of 0.5µm polystyrene latex (ex Polyscience) were taken and the surface functionalised to have free carboxylate groups. The bulk of the particles have small amounts of fluorescent dye incorporated.

All reactions took place in 2ml Eppendorf microcentrifuge tube at room temperature.

• 1) A 0.5ml portion of 2.5% latex was taken and rinsed three times with 1.5 ml of 0.01M carbonate buffer at pH 9.6 (Centrifuge, decant, resuspend).
• 2) The latex was rinsed a further three times using 0.02M phosphate buffer at pH 6.0.
• 3) The latex was resuspended in 0.6ml of phosphate buffer then added to 0.6ml of 2% 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride and allowed to react for 3 hours, centrifuged and decanted.
• 4) The resulting compound was rinsed three times in 1.5 ml of 0.2M borate buffer at pH8.5, and resuspended in borate buffer followed by addition of 0.3 ml of a solution containing 160 µg of cellulase obtained from Trichoderma reesei in borate buffer. The reactants use left to react overnight.
• 5) 20ul of 0.25M ethanolamine was added for one hour to react with any unreacted coupling sites.
• 6) The dispersion was centrifuged and resuspended in 1ml of borate buffer.

The resulting mixture was used to treat cotton as follows
1) Two 5x5cm squares of white cotton were added to 38 ml of liquor containing 0.001 mol / l carbonate buffer at pH 9.6, 1 g / l of a surfactant system comprising 50% PAS, 35% Synperonic A7 and 15% Synperonic A3 and 5.0 ppm of the fluorescent latex. Two conditions were examined:

• i) unmodified latex
• ii) cellulase-modified latex

A 5% solids dispersion was prepared, where the particles consisted of a surfactant mesophase of composition (by mole fraction) 0.55 octadecanol: 0.40 cetyl sodium sulphonate : 0.05 stearic acid.

Cellulase obtained Trichoderma reesei was covalently attached to the particles using the following method:

• 1) 10g of the 5% dispersion was added to 10ml of 0.02 mol /l phosphate buffer at pH 6.5
• 2) To the mixture was added 0.48ml of 2% 1-ethyl-3-(dimethylaminopropyl) carbodiimide hydrochloride and allowed to react for three hours
• 3) pH was raised to 8.5 by addition of 1 mol / l sodium hydroxide
• 4) 1ml of a solution containing 5 mg of cellulase from Trichoderma reesei in 0.2 mol/l borate buffer at pH 8.5 was added and allowed to react overnight
• 5) 20 µl of 0.25 mol/l ethanolamine was added to react with any unreacted coupling sites.

The resulting mixture was used to treat cotton Terry towelling sheets to demonstrate an antiharshening benefit
1) 40g of 20x20cm Terry Towelling squares were added to 1000 ml of liquor in a Tergotometer pot at ambient temperature. Three different liquors were examined:

• i) water only
• ii) water plus 4 g/l of the unmodified dispersion
• iii) water plus 4 g/l of the cellulase-modified dispersion

All preparations took place in 2 ml Eppendorf microcentrifuge tube at room temperature. The latex used was a 2.5% dispersion of 0.5 µm polystyrene latex particles whose surface has carboxylate groups incorporated. The latex has a small amount of fluorescer incorporated.

• 1) A 0.5 ml portion of 2.5% latex was taken and rinsed three times with 1.5 ml of 0.1 M carbonate buffer at pH 9.6 using a centrifuge, decant, resuspend technique.
• 2) The latex was rinsed three times in 1.5 ml of 0.2 M borate buffer at pH 8.5, and resuspended in borate buffer followed by addition of 0.3 ml of a solution containing 160 µg of cellulase obtained from Trichoderma reesei in borate buffer. The dispersion was left overnight for the cellulase to adsorb.
• 3) The dispersion was centrifuged and resuspended in 1 ml of phosphate buffer.

The resulting mixture was used to treat cotton as follows;
1) Two 5 x 5 cm squares of white cotton were added to 38 ml of liquor containing 0.01 mol / l phosphate buffer at pH 7.0 and 5 ppm of the fluorescent latex. Three conditions were examined:

• i) unmodified latex
• ii) latex with covalently attached cellulase prepared as described in Example 1
• iii) latex with physisorbed cellulase prepared as described in this example

A number of latex dispersions were prepared each having a different cellulase enzyme covalently attached according to the method described in Example 1. Four different cellulases were used:

• i) cellulase from Trichoderma reesei
• ii) cellulase EG2 from Trichoderma longibrachiatum
• iii) cellulase EG3 from Trichoderma longibrachiatum
• iv) cellulase E5 from Thermonospora fusca

The latices were used to treat cotton according to the method described in Example 3. The results are shown in Table 4. Latex % deposited unmodified 5.2 modified with cellulase from Trichoderma reesei 65.2 modified with EG2 from Trichoderma longibrachiatum 55.7 Modified with EG3 from Trichoderma longibrachiatum 15.6 Modified with E5 from Thermonospora fusca 34.5

• 1) 2.5 g of a carboxylated silicone (TP502 from Union Carbide) was dispersed in 2.5 g of 0.02 M pH 6.5 phosphate buffer.
• 2) 2.5 g of 1-ethyl-3-(dimethylaminopropyl) carbodiimide hydrochloride in 2.0 ml of 0.02 M pH 6.5 phosphate buffer was added dropwise to the silicone dispersion. The mixture was agitated for 3 hours on a bottle roller.
• 3) Sodium hydroxide was added to raise the pH to 8.5
• 4) 0.032 g of cellulase from Trichoderma reesei in 1.0 ml of 0.2 M pH 8.5 borate buffer was added to the dispersion. This was agitated overnight on a bottle roller
• 5) 4 ml of 0.25 M ethanolamine was added and mixed for 1 hour

The cellulase-modified silicone was incorporated into a model wash and a model rinse. In each case two controls were also used: incorporation of unmodified silicone and the use of no silicone at all. The fabrics used in the experiments were 20 x 20 cm squares of white Terry towelling. The model washes and rinses were performed in a Tergotometer using the following protocols:

1 litre of demineralised water was added to a Tergotometer pot. If used, 0.2 g of the appropriate silicone was added. The liquor was maintained at ambient temperature. 40 g of the 20 x 20 cm squares of Terry towelling were added to the pot which was then agitated at 60 rpm for 5 min. The cloths were then spun dry for 30 s in a domestic spin drier and finally line dried.

1 litre of demineralised water was added to a Tergotometer pot. This was kept at a constant 40°C. 1 g of LAS (Petrelab 550, sodium salt) was added and, if used, 0.2 g of the appropriate silicone. 40 g of the 20 x 20 cm squares of Terry towelling were added to the pot which was then agitated at 60 rpm for 30 min. The cloths were given 2 x 5 min rinses in demineralised water then spun dry for 30 s in a domestic spin drier and finally line dried.

The cloths were then evaluated, both instrumentally using an in-house Harshness meter and by a panel using a round-robin paired comparison protocol where each cloth is judged against every other cloth. The results are given in Table 5 Conditions Harshness score Panel Preference score rinse containing no silicone 266 ± 5 0.069 rinse containing unmodified silicone 265 ± 8 0.096 rinse containing cellulase-modified silicone 236 ± 4 0.610 wash containing no silicone 281 ± 5 0.057 wash containing unmodified silicone 286 ± 4 0.057 wash containing cellulase-modified silicone 272 ± 8 0.111

In the case of both the wash and the rinse treatment, the panel judged the treatment containing the cellulase-modified silicone to deliver greater softness than the two controls.

In each case this was statistically significant at the 95% confidence level

5 g of a mixture consisting of 85% 1,2-bis(hardened tallowoyloxy)-3-trimethylammonium propane chloride, 8% stearic acid and 7% propylene glycol was melted at 80°C and then added to 95 g of distilled water at 80°C accompanied by vigourous stirring. The mixture was cooled to ambient temperature while maintaining the stirring and resulted in a fine dispersion of the material in water. 50 g of this dispersion was added to 50 ml of 0.02 M pH 6.5 phosphate buffer and mixed to form a homogeneous dispersion. 3.53 ml of 2% 1-ethyl-3-(dimethylaminopropyl) carbodiimide hydrochloride in 0.02 M pH 6.5 phosphate buffer was added dropwise to the dispersion. This was agitated for 3 hours on a bottle roller at ambient temperature. Sodium hydroxide solution was then added to raise the pH to 8.5. 0.1 g of cellulase from Trichoderma reesei in 1 ml of 0.2 M pH 8.5 borate buffer was added. The mixture was agitated overnight on a bottle roller at ambient temperature. 0.1 ml of 0.25 M ethanolamine was added and the mixture agitated for 1 hour.

The cellulase-modified dispersion was incorporated into a model wash. Two controls were also used: incorporation of unmodified dispersion and the use of no cationic surfactant dispersion at all. The fabrics used in the experiments were 20 x 20 cm squares of white Terry towelling. The model washes were performed in a Tergotometer using the following protocol:

1 litre of demineralised water was added to a Tergotometer pot. This was kept at a constant 40°C. 1 g of LAS (Petrelab 550, sodium salt) was added and, if used, 0.2 g of the appropriate cationic surfactant dispersion. 40 g of the 20 x 20 cm squares of Terry towelling were added to the pot which was then agitated at 60 rpm for 30 min. The cloths were given 2 x 5 min rinses in demineralised water then spun dry for 30 s in a domestic spin drier and finally line dried.

The cloths were then evaluated, both instrumentally using an in-house Harshness meter and by a panel using a round-robin paired comparison protocol where each cloth is judged against every other cloth. The results are given in Table 6. Conditions Harshness score Panel Preference score unwashed fabric 263 ± 6 0.152 cationic-free wash 270 ± 10 0.067 wash containing unmodified cationic 291 ± 10 0.122 wash containing cellulase modified cationic 259 ± 7 0.658

The panel judged the cloths washed with a formulation containing the cellulase-modified cationic surfactant dispersion to be softer than the two controls. The panel also judged that this treatment had rendered the fabric softer than it was before undergoing the wash. These panel results were significant at the 95% confidence level.

For this work a sample of a 0.5 µm polystyrene latex having a surface containing free amine groups was obtained from Sigma. The latex also contained a small amount of a fluorescent dye.

Two modified latices were prepared using different levels of cellulase.

• 1) 1.0 ml of a 2.5% dispersion of the latex was placed in an Eppendorf tube.
• 2) The latex was washed three times with 1.5 ml portions of phosphate buffered saline using a centrifuge / decant /resuspend technique.
• 3) The final pellet was resuspended in 8% glutaraldehyde solution and agitated overnight at ambient temperature.
• 4) The pellet was then washed a further three times using phosphate buffered saline.
• 5) Either 160 µg or 500 µg of cellulase from Trichoderma reesei was added to the dispersion and agitated for five hours at ambient temperature.
• 6) The dispersion was centrifuged and the pellet resuspended in 1.0 ml of 0.5 M ethanolamine and then agitated for 30 minutes at ambient temperature.
• 7) The latex was centrifuged and finally resuspended in 1.0 ml of phosphate buffered saline.

The resulting mixture was used to treat cotton as follows
1) Two 5 x 5 cm squares of white cotton were added to 38 ml of liquor containing 0.01 mol / l carbonate buffer at pH 9.6 and 15 ppm of the fluorescent latex. Three conditions were examined:

• i) unmodified latex
• ii) latex modified with low level of cellulase
• iii) latex modified with high level of cellulase.