AU2013357704B2

AU2013357704B2 - Detergent composition

Info

Publication number: AU2013357704B2
Application number: AU2013357704A
Authority: AU
Inventors: Jayashree Anand; Prachi Makarand DESAI; Amit Deshpande; Shailesh Sadanand NAIK
Original assignee: Unilever PLC
Current assignee: Unilever PLC
Priority date: 2012-12-12
Filing date: 2013-11-26
Publication date: 2016-07-07
Anticipated expiration: 2033-11-26
Also published as: CL2015001612A1; EP2931865A1; BR112015012348A2; WO2014090568A1; SA515360547B1; EP2931865B1; CN104822816A; AU2013357704A1; BR112015012348A8; CN104822816B; ZA201504070B

Abstract

The present invention relates to a detergent composition for effective stain removal. It is an object of the present invention to provide a detergent composition having a non- phosphate precipitating builder which is effective against hydrophobic stains. It is yet another object of the present invention to provide a detergent composition which can be used at lower wash temperatures. It is yet another object of the present invention to provide a detergent composition which is environment friendly. It has been determined by the present inventors that a detergent composition having a combination of specific bleach activator, a non-phosphate precipitating builder and an enzyme provides for effective removal of stains particularly the tough hydrophobic stains.

Description

DETERGENT COMPOSITION

Field of the invention

The present invention relates to a detergent composition for effective stain removal.

The invention has been developed primarily for use in detergent compositions and will be described hereinafter with reference to this application. However, it will be appreciated that the invention is not limited to this particular field of use.

Background of the invention

Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of the common general knowledge in the field.

Washing of used fabrics with a detergent composition to remove dirt and stains is common practice. Surfactants present in the detergent composition act on dirt and stain and suspend them in the wash liquor. The suspended particles are subsequently removed at the time of rinsing. Surfactants are prone to precipitate by reacting with some ions namely Ca2+ and Mg2+ which are often present in wash liquor. The precipitation of the surfactants reduces the cleaning efficiency.

Builders are added to the detergent composition primarily to complex with Ca+2 and Mg2+ and thereby reduce hardness of water. In addition to removing Ca2+ and Mg2+ ions, some builders also emulsify soil particles, reduce soil re-deposition by suspending the soil in the wash liquor and provide alkalinity which assists in dissolving oil-based soils. Use of an ineffective builder or the use of an ineffective amount of a builder lessens the cleaning performance of surfactants.

Builders are classified as sequestering, precipitating or ion exchange builders. Sodium tripolyphosphate is a phosphate type sequestering builder which, in addition to removing the dissolved ions, helps disperse and suspend soil in the wash liquor and emulsifies oily material. For this reason phosphates such as tripolyphosphates and pyrophosphates have been widely used as builders. The effect of phosphates upon the eutrophication of lakes and streams has been questioned and their use in detergent compositions has been subject to government scrutiny and regulation.

Alternatives for phosphate builders have been known. However such alternatives have one or the other drawbacks.

Zeolites, used as alternative builders are ion-exchange builders which provide benefits comparable to phosphate builders but are not desirable as they are water insoluble and can foul sewer lines and water treatment facilities.

Precipitating builders, for example sodium carbonate, are environment friendly and removes Ca2+ and Mg2+ ions as precipitated calcium and magnesium particles. Use of precipitating builders may reduce the cleaning activity by deposition of precipitated calcium and magnesium particles on the fabric. Further, as compared to the phosphate builders, precipitating builders have slow Ca2+ and Mg2+ ions removal efficiency and are ineffective at completely preventing precipitation of surfactants owing to their reaction with calcium and magnesium ions. This further reduces the cleaning efficiency of detergent composition having precipitating builders.

Bleaches are yet another widely used ingredient in the detergent composition that removes stain. Peroxygen bleach compounds can bleach stains without damaging the colour of the fabrics and hence are widely used. To bleach stains at temperature below 60°C requires bleach activators in combination with peroxygen bleach compounds. Under the action of a bleach, stains are oxidized and broken into fragments which are later suspended in the solution by the surfactant. A lowered efficiency of surfactant in presence of precipitating builder may also affect the bleach efficiency. Presence of clay or soil on the fabric further reduces bleaching of hydrophobic stains.

Hence it is difficult to achieve effective dirt and stain removal with a detergent composition having precipitating builder but which does not cause eutrophication of lakes and streams and which is environment friendly. It is therefore desired to provide a detergent composition with a precipitating builder for effective removal of bleachable stains. It is further desired to provide a detergent composition having a non-phosphate precipitating builder that effectively removes tough hydrophobic stains.

Detergent compositions having peroxygen bleach compound and hydrophobic bleach activator are known in the art. US5043089 (1991, Akzo N.V) discloses a novel p-sulphophenyl alkyl carbonates where the alkyl group contains 6 to 10 carbon atoms providing an effective bleach activator. This application also discloses a detergent composition having the bleach activator, a bleaching agent and a surfactant. This application does not disclose a detergent composition having non-phosphate builders for providing effective stain removal. GB2395488A (2004, Reckitt Benckiser N. V.) discloses a process of removing coloured stains from hydrophobic surfaces by treating with a formulation having a salt of sulphophenyl alkyl carbonate. The formulation may additionally include an oxygen source, a builder, a surfactant and preferably encapsulated enzyme. This application discloses detergent compositions having phosphate builders.

The present invention seeks to provide a detergent composition having a nonphosphate precipitating builder which effectively removes hydrophobic stains.

The present invention seeks to provide a detergent composition which can be used at lower wash temperatures.

The present invention seeks to provide a detergent composition which is environment friendly.

It has been determined by the present inventors that a detergent composition having a combination of specific bleach activator, a non-phosphate precipitating builder and an enzyme may provide for effective removal of stains particularly the tough hydrophobic stains.

Summary of the invention

According to the first aspect, the present invention provides a detergent composition comprising: (i) a precipitating builder; (ii) 0 to 5 wt% of zeolites or a phosphate sequestering builder or mixtures thereof; (iii) 2 to 80 wt% surfactant; wherein the composition comprises: (i) an enzyme; and, (ii) a bleach activator of the general formula (I)

and where R is an alkyl group with 6 to 10 carbon atoms and M+ is a cation, wherein the enzyme is a mixture of lipase, mannanase, amylase and protease enzymes.

According to the second aspect, the present invention provides for a method of bleaching a bleachable substrate comprising the steps of: (i) applying to the substrate a neat or diluted form of the composition of the first aspect; (ii) rinsing the substrate.

According to the third aspect disclosed is a use of the detergent composition of the first aspect for bleaching tough hydrophobic stains.

The invention will now be explained in more details.

Detailed description of the invention

In accordance with a first aspect, the invention provides a detergent composition having a precipitating builder, a surfactant, a bleach activator and an enzyme.

Precipitating builder

Builders used in the detergent composition may be classified in various ways. One method of classification of detergent builders is based on their mode of action and includes classification into sequestering, precipitating and ion-exchange builders. Another conventional method of classification of detergent builders is to classify them as inorganic and organic detergent builders. Yet another method of classification is based on their solubility in water and is accordingly classified as water soluble or water insoluble builders.

Disclosed detergent composition includes a precipitating builder. In contact with the ions Ca2+ and Mg2+ generally present in the wash liquor precipitating builders precipitate out as a complex with the water hardness cations (Ca2+ and Mg2+), thereby performing a builder function. Specific examples of precipitating builders include sodium fatty acid sulphonate, long chain fatty acid soaps, water-soluble salts of carbonates, bicarbonates, sesquicarbonates, silicates, aluminates and oxalates. Alkali metal salts, especially sodium salts of the foregoing materials are preferred for convenience and economy. Preferably the precipitating builder is a water-soluble carbonate salt. It is highly preferred that the precipitating builder is sodium carbonate. It is highly preferred that the precipitating builder of the present invention is a nonphosphate precipitating builder. Preferably the precipitating builder is present from 5 wt% to 80 wt% in the composition, more preferably from 10 wt% to 60 wt%, still more preferably from 12 wt% to 30 wt% and most preferably from 15 wt% to 25 wt%. A crystallization seed may be used in the detergent composition along with the precipitating builder; such crystallization seed quickens the rate of precipitation of the metal cations, and thereby removes the hardness before it can adversely affect detergency performance.

Zeolites and Sequestering builders

Disclosed detergent composition includes 0 to 5 wt% of a zeolites or a phosphate sequestering builder or mixtures thereof.

Zeolites:

Disclosed detergent composition includes 0 to 5 wt% of zeolites. It is preferred that the detergent composition of the present invention not more than 4wt%, further preferably not more than 2wt% of zeolites and highly preferred composition is free of the zeolite builders.

Zeolites are ion-exchange builders and are substantially water insoluble builders which are capable of reducing the hardness content of laundering liquors. Ion-exchange builder may be crystalline or amorphous aluminosilicates. Aluminosilicates can be naturally occurring aluminosilicates or synthetically derived. Preferred synthetic crystalline aluminosilicate ion-exchange materials useful herein are available under the designations Zeolite A, Zeolite B, Zeolite X, Zeolite HS and mixtures thereof. In an especially preferred embodiment, the crystalline aluminosilicate ion-exchange material is Zeolite A.

Another preferred aluminosilicate zeolite is zeolite MAP builder. Zeolite MAP is described in EP 384070A (Unilever). It is defined as an alkali metal alumina-silicate of the zeolite P type having a silicon to aluminium ratio not greater than 1.33, preferably not greater than 1.15 and, more particularly, not greater than 1.07 and preferably within the range of from 0.9 to 1.2.

Sequestering builder:

Disclosed detergent composition includes 0 to 5 wt% of a phosphate sequestering builder. It is preferred that the detergent composition of the present invention includes not more than 4wt%, further preferably not more than 2wt% of the phosphate sequestering builders and highly preferred composition is free of the phosphate sequestering builders.

Sequestering builders are water soluble builder that forms water soluble complexes with Ca2+ and Mg2+ ions. Phosphate sequestering builders include orthophosphates, tripolyphosphate, alkali metal pyrophosphates and organic phosphonates. Examples of the phosphate sequestering builders include sodium tripolyphosphate, tetrasodium pyrophosphate, hexametaphosphate, and tetrapotassium pyrophosphate. Examples of organic phosphonates includes the sodium and potassium salts of ethylene diphosphonic acid, the sodium and potassium salts of ethane 1-hydroxy-1,1 diphosphonic acid, and the sodium and potassium salts of ethane-1,1,2-triphosphonic acid.

Examples of non-phosphate sequestering builders that may be present in the detergent composition of the present invention for use as builders includes hydrocarboxylates (citrates, tartrates, succinates, gluconates), polycarboxylates, aminocarboxylates (ethylenediaminetetraacetate(EDTA), and nitrilotriacetate (NTA)) diethylene triamine pentaacetic acid (DTPA), hydroxyethylene diamine triacetic acid (HEDTA), dihydroxyethyl glycine (DEG), and triethanolamine.

Surfactant

Disclosed detergent composition includes 2 to 80 wt% surfactant. It is preferred that the detergent composition includes atleast 10 wt% surfactant more preferably at least 20wt% and still more preferably atleast 30wt% of the surfactant. It is preferred that the disclosed detergent composition includes not more than 70wt%, preferably not more than 60wt% and more preferably not more than 50wt% and still preferably not more than 40wt% of the surfactant.

Disclosed cleaning composition preferably includes a surfactant. The surfactant may be a soap or an anionic, nonionic, amphoteric, zwitterionic or cationic surfactant or mixtures thereof. In general, the nonionic and anionic surfactant may be chosen from the surfactants described in "Surface Active Agents" Vol. 1, by Schwartz and Perry, Interscience 1949, Vol. 2 by Schwartz, Perry and Berch, Interscience 1958, in the current edition of "McCutcheon ' s Emulsifiers and Detergents" published by Manufacturing Confectioners Company or in "Tenside-Taschenbuch", H.Stache, 2nd Edn., Carl Hauser Verlag, 1981.

Suitable anionic surfactant includes water-soluble alkali metal salts of organic sulphates and sulphonates having alkyl radicals containing from about 8 to about 22 carbon atoms, the term alkyl includes the alkyl portion of higher acyl radicals.

Examples of suitable synthetic anionic surfactant are sodium and potassium alkyl sulphates. Especially preferred are the sodium and potassium sulphates obtainable by sulphating higher C8 to C18 alcohols for example from tallow or coconut oil. Other preferred anionic surfactant include sodium and potassium alkyl C9 to C2o benzene sulphonates, particularly sodium linear secondary alkyl C10 to C15 benzene sulphonates; and sodium alkyl glyceryl ether sulphates, especially those ethers of the higher alcohols derived from tallow or coconut oil and synthetic alcohols derived from petroleum.

Most preferred anionic surfactants are sodium lauryl ether sulfate (SLES), particularly preferred are anionic surfactant with 1 to 3 ethoxy groups, sodium C10 to C15 alkyl benzene sulphonates (LAS) and sodium C12 to Ci8 alkyl sulphates (PAS). Alkyl ester suphonates such as methyl ester sulphonates (MES) may be preferably used for replacing a portion or completely replacing the anionic surfactant.

Other suitable surfactants are those described in EP-A-328 177 (Unilever), which shows resistance to salting-out, the alkyl polyglycoside surfactants described in EP-A-070 074 and alkyl monoglycosides. The surfactant chain may be branched or linear. Suitable nonionic surfactants include the reaction products of compounds having a hydrophobic group and a reactive hydrogen atom, for example, aliphatic alcohols, acids, amides or alkyl phenols with alkylene oxides, especially ethylene oxide either alone or with propylene oxide. Preferred nonionic surfactants are C6 to C22 alkyl phenol-ethylene oxide condensates, generally having 5 to 25 EO, i.e. 5 to 25 units of ethylene oxide per molecule, and the condensation products of aliphatic C8 to Ci8 primary or secondary linear or branched alcohols with ethylene oxide, generally 5 to 50 EO. Preferably, the non-ionic is 10 to 50 EO, more preferably 20 to 35 EO. Alkyl ethoxylates are particularly preferred.

Soaps may also be present. The fatty acid soap used preferably contains from about 16 to about 22 carbon atoms, preferably in a straight chain configuration. Preferred soap may be derived from saturated and non-saturated fatty acids obtained from natural sources and synthetically prepared. Examples of such fatty acids include capric, lauric, myristic, palmitic, stearic, oleic, linoleic and linolenic acid. The anionic contribution from soap is preferably from 0 to 30 wt% of the total anionic.

Preferred surfactant systems are mixtures of anionic with nonionic surfactant, in particular the groups and examples of anionic and nonionic surfactants pointed out in EP-A-346 995 (Unilever).

Amounts of amphoteric or zwitterionic surfactants can also be used in the compositions of the invention but this is not normally desired owing to their relatively high cost. If any amphoteric or zwitterionic surfactants are used, it is generally in small amounts in combinations with anionic and nonionic surfactants.

Enzyme

Disclosed detergent composition includes an enzyme. Preferably the enzyme is selected from protease, lipase, amylase, mannanase or mixtures thereof.

Protease:

Disclosed detergent composition preferably includes a protease. Suitable protease includes those of animal, vegetable or microbial origin. Protease from microbial origin is preferred. Protease may also be chemically modified or protein engineered mutant. Preferably the protease is a serine protease or a metallo protease, preferably an alkaline microbial protease or a trypsin-like protease. Examples of alkaline proteases are subtilisins, especially those derived from Bacillus, examples include subtilisin Novo, subtilisin Carlsberg, subtilisin 309, subtilisin'!47 and subtilisin 168 (described WO8906279A1). Examples of trypsin-like proteases are trypsin from porcine or bovine origin and the Fusarium protease described in W08906270A1 and W09425583A1.

The protease is preferably from B.subtilis. Preferred commercially available protease includes Alcalase™, Savinase™, Primase™, Duralase™, Dyrazym™, Esperase™, Everlase™, Polarzyme™, and Kannase™, Maxatase™, Maxacal™, Maxapem™, Properase™, Purfast® , Effectenz® , Purafect™, Purafect OxP™, FN2™, and FN3™ (Genencor International Inc.).

Protease from a strain of Bacillus having maximum activity throughout the pH range of 8 to 12 is highly preferred and includes commercially available Esperase™ and Savinase™.

Preferably the detergent composition of the present invention include 0.001 wt% to 10 wt% more preferably from 0.01 wt% to wt% of protease depending upon their activity.

Lipase:

Disclosed detergent composition preferably includes a lipase. Lipase catalyses hydrolysis of ester bonds of edible fats and oils, i.e. triglycerides, into free fatty acids, mono- and diglycerides and glycerol.

Preferred lipases include those of bacterial or fungal origin. Chemically modified or protein engineered mutants are included. Examples of useful lipases include lipases from Humicola species (incl. Thermomyces. species) which includes lipase from H. lanuginosus (T. lanuginosus) as described in EP0258068B1 and EP0305216B1 or from H. insolens as described in WO9613580A1 or lipases from Pseudomonas species which includes lipase from P. alcaligenes or P. pseudoalcaligenes (EP0218272 A1), P. cepacia (EP0331376B1), P. stutzeri (GB 1 ,372,034), P. fluorescens, Pseudomonas species strain SD 705 (W095/06720 and W096/27002), P. wisconsinensis (WO96/12012) or lipases from Bacillus species which includes lipases from B. subtilis (Dartois et al. (1993), Biochemica et Biophysica Acta, 1131 , 253-360), B. stearothermophilus (JP64/744992) or B. pumilus (WO 91/16422). Other examples include lipase variants such as those described in WO92/05249, WO94/01541, EP407225, EP260105, W095/35381, W096/00292, WO95/30744, W094/25578, W095/14783, W095/22615, W097/04079 and W097/07202.

Preferred commercially available lipases are available under the trademarks Lipoclean®, Lipolase®, Lipolase® Ultra and Lipex ®. LIPEX ® is particularly preferred, and LIPEX® 100 T is further particularly preferred. The activity of commercial lipase is commonly expressed as Lipase Units or LU. Different lipase preparations may have different activities. For fungal lipases these may range from 2,000 to 2,000,000 LU per gram. Preferred compositions include lipase having 5 to 20000LU/g.

In order to prevent accidents and to alleviate safety concerns, commercial lipases are always coated with an inert material. Therefore, commercial lipases that are used for detergent powders, bars and tablets are in granular form containing very low amount of active lipase and balance of adjunct materials. Such granulates contain lipase concentrate, inorganic salt, binders and coating materials. They are free-flowing so that there is no lumping, and the granulate dissolve faster. Lipases are also available in liquid form, example LIPEX® 100 L.

Preferred detergent composition has 0.0001wt% to 0.3wt% lipase, more preferably from 0.0001 to 0.1wt% lipase and further preferably 0.0009wt% to 0.00186 wt% lipase.

Amylase:

Disclosed detergent composition preferably includes an amylase. Suitable amylases (alpha-amylase and/or beta-amylase) include those of bacterial or fungal origin. Chemically modified or protein engineered mutants are included. Examples of amylase suitable for the present invention includes alpha-amylase obtained from Bacillus species which includes special strain of B. licheniformis, described in more detail in GB 1,296,839, or the Bacillus species strains disclosed in WO 95/026397 or WO 00/060060. Other suitable examples of amylases are the variants described in WO 94/02597, WO 94/18314, WO 96/23873, WO 97/43424, WO 01/066712, WO 02/010355 and WO 02/031124 (which references all incorporated by reference).

Commercially available amylases are Duramyl(TM), Termamyl(TM), Termamyl Ultra(TM), Natalase(TM), Stainzyme(TM), Stainzyme Plus(TM), Fungamyl(TM) and BAN(TM) (Novozymes A/S), Rapidase(TM) and Purastar(TM) (from Genencor International Inc.).

Mannanase:

Preferably the disclosed composition includes mannanase. Examples of suitable mannanase include those of bacterial or fungal origin. Preferably the mannanase is derived from a strain of a filamentous fungus genus Aspergillus, preferably Aspergillus niger or Aspergillus aculeatus (WO 94/25576). WO 93/24622 disclosing a mannanase isolated from Trichoderma reese is also preferred. Mannanases have also been isolated from several bacteria, including Bacillus species. 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.

Examples of preferred commercially available mannanases include Mannaway(TM) available from Novozymes NS Denmark.

Bleach activator

Disclosed detergent composition includes a bleach activator of the general formula

«) and where R is an alkyl group with 6 to 10 carbon atoms and M+ is a cation.

Preferably the alkyl group R is selected from n-hexyl, n-octyl or 2-ethylhexyl.

Preferably the cation M+ is sodium or potassium. It is highly preferred that the bleach activator is sodium 4-sulphophenyl 2-ethylhexyl carbonate.

The bleach activator may be in the form of a powder or as particulate bodies having the bleach activator, a binder or agglomerating agent. It is preferred for reasons of stability and handling that the bleach activator is in the form of particulate bodies.

Peroxyqen bleach compound:

Disclosed composition preferably includes a peroxygen bleach compound capable of yielding hydrogen peroxide in aqueous solution. Hydrogen peroxide sources are well known in the art. Hydrogen peroxide sources are described in details in Kirk Othmer's Encyclopedia of Chemical Technology, 4th Ed (1992, John Wiley & Sons), Vol. 4, pp. 271-300 "Bleaching Agents (Survey)", and include the alkali metal salts of sodium perborates and sodium percarbonates, including various coated and modified forms. Suitable peroxygen bleach compounds include hydrogen peroxide or any of its solid adducts such as organic peroxides example; urea peroxide and inorganic persalts such as the alkali metal perborates, percarbonates, perphosphates, persilicates and persulphates. Mixtures of two or more such compounds may also be suitable.

Preferred inorganic persalts are sodium perborate monohydrate and tetrahydrate, and sodium percarbonate. Percarbonate is stable during storage and dissolves quickly in the cleaning liquor and is especially preferred. It is believed that such rapid dissolution results in the formation of higher levels of percarboxylic acid and, thus, enhances substrate bleaching performance. Highly preferred percarbonate is in uncoated or coated form. Preferably the average particle size of uncoated and coated percarbonate ranges from about 400 to about 1200 pm, most preferably from about 400 to about 600 pm. If coated percarbonate is used, the preferred coating materials include mixtures of carbonate and sulphate, zeolite, precipitated silica, waxes, borates, polymers, citrates, silicate, borosilicate or fatty acids.

Preferably the disclosed detergent composition has 4 to 35 wt% of the peroxygen bleach compound more preferably 5 to 20 wt % and further preferably 10 to 15 wt% of the peroxygen bleach compound.

Form of detergent composition:

Preferably the disclosed detergent composition is a granular detergent composition. Preferably the granular detergent composition is of a low to moderate bulk density. Preferred granular detergent composition may be made of any known methods for manufacturing a granular detergent composition that includes spray-drying, drum drying, fluid bed drying, and scraped film drying preferably using the wiped film evaporator.

Alternatively, the granular detergent composition may be in a ‘concentrated’ or ‘compact’ form. Such detergent composition may be prepared by mixing and granulating process, for example, using a high-speed mixer or granulator, or other nontower process.

Preferably the pH of the aqueous solution on dissolution of the detergent composition is 6 to 12 and more preferably from 7 to 10.5.

Optional ingredients:

Disclosed detergent composition may include one or more of other ingredients selected from bleach stabilizer, polymers, perfumes, fluorescers, soil release polymers, germicides, colourants and coloured speckles. This list is not intended to be exhaustive.

Disclosed composition may include a bleach stabiliser. Suitable bleach stabilisers include ethylenediamine tetraacetate (EDTA), ethylenediamine disuccinate (EDDS), and the aminopolyphosphonates such as ethylenediamine tetramethylene phosphonate (EDTMP) and diethylenetriamine pentamethylene phosphonate (DETPMP).

When present the composition may include one or more polymers. Examples include carboxymethylcellulose, poly (ethylene glycol), poly (vinyl alcohol), polycarboxylates such as polyacrylates, maleic/acrylic acid copolymers and lauryl methacrylate/acrylic acid copolymers. Suitable commercially available polymer includes Sokalan CP5 (ex BASF) which is a polyacrylate, namely maleic acid-acrylic acid copolymer, with a sodium salt.

Disclosed detergent composition may also include perfumes. When present the perfumes could be of natural origin or synthetic. They include single compounds or mixtures of compounds. By perfume in this context is not only meant a fully formulated product delivering fragrance, but includes selected components of that fragrance, particularly those which are prone to loss, such as the so-called top notes. Preferably perfume may be used in the form of neat oil or in an encapsulated form.

Disclosed composition may also include fluorescent agent (optical brightener).

Fluorescent agents are well known and many such fluorescent agents are available commercially. Usually, these fluorescent agents are supplied and used in the form of their alkali metal salts, for example, the sodium salts. The total amount of the fluorescent agent or agents used in the composition is generally from 0.005 to 2 wt%, more preferably 0.01 to 0.1 wt%. Preferred fluorescent agent includes but not limited to di-styryl biphenyl compounds, e.g. Tinopal (Trade Mark) CBS-X, diamine stilbene di-sulphonic acid compounds, e.g. Tinopal DMS pure Xtra and Blankophor (Trade Mark) HRH and pyrazoline compounds, e.g. Blankophor SN. Preferred fluorescers are: sodium 2- (4-styryl-3-sulfophenyl) -2H-napthol [l,2-d]triazole, disodium 4, 4 ' -bis {[ (4-anilino-6- (N methyl-N-2 hydroxyethyl) amino 1, 3, 5-triazin-2-yl) ] amino} stilbene-2-2 ' disulfonate and disodium 4,4'- bis (2-sulfoslyryl) biphenyl. Tinopal® DMS is the disodium salt of disodium 4,4'-bis{[(4-anilino-6-morpholino-1,3,5-triazin-2-yl)]amino} stilbene-2-2' disulfonate. Tinopal® CBS is the disodium salt of disodium 4,4'-bis(2-sulfostyryl)biphenyl.

Disclosed composition may include a soil release polymer, for example sulphonated and unsulphonated PET/PEOT polymers, both end-capped and non-end-capped, and polyethylene glycol/polyvinyl alcohol graft copolymers such as Sokolan (Trade Mark) HP22. Especially preferred soil release polymer are the sulphonated non-end-capped polyesters described and claimed in W09532997A (Rhodia Chimie)

In accordance with a second aspect, disclosed invention provides a method1 of bleaching a bleachable substrate comprising the steps of applying to the substrate a neat or diluted form of the composition as according to the first aspect; and rinsing the substrate.

In accordance with a third aspect, disclosed invention provides an use of a detergent composition as claimed in any one of the preceding claims for effective removal of tough hydrophobic stains.

The invention will now be explained in details with the help of non-limiting exemplary embodiments.

Examples

Evaluation of the preferred and the comparative compositions in removal of tough hydrophobic stains (lipstick stain and tomato ketchup stain): a) Measurement of Soil Release Index (SRI)

Soil release index (SRI) is a measure of the amount of a stain present on fabric that is removed during a washing process. The intensity of any stain after washing is measured by means of a spectrophotometer and expressed in terms of the difference between the stained fabric and a clean fabric giving ΔΕ* for each stain. It is defined as ΔΕ* and is calculated as:

L*, a*, arid b* are the coordinates of the CIE 1976 (L*, a*, b*) colour space, determined using a standard spectrophotometer. ΔΕ* can be measured before and after the stain is washed, to give AE*bw (before wash) and AE*aw (after wash). ΔΕ after wash is the difference in L a b colour space between the clean (unwashed) fabric and the stained fabric after wash. So a ΔΕ after wash of zero means that a stain is completely removed. SRI is defined as: SRI = 100- AE*aw A SRI of 100 means complete removal of a stain. The higher the SRI value, the greater is the stain removal potential.

The clean (or virgin) fabric is an "absolute standard". For each experiment, it refers to an identical piece of fabric to that to which the stain is applied. Therefore, its point in L a b colour space stays constant. b) Preparation of the preferred and comparative detergent composition A control detergent composition (Control) was formulated with sodium carbonate as the precipitating builder and 2.6% zeolite 4A. The control composition had no bleach, no bleach activator and no enzyme. Other standard laundry detergents were included.

The composition of Control is provided in Table 1. A first comparative detergent composition (Comp A) was formulated by adding sodium 4-sulphophenyl 2-ethylhexyl carbonate (bleach activator according to the invention) and sodium percarbonate (bleach) to the control composition. The first comparative detergent composition had no enzyme. A second comparative detergent composition (Comp B) was formulated by adding enzymes protease, lipase, amylase and mannanase to the control composition. The second comparative detergent composition had no sodium 4-sulphophenyl 2-ethylhexyl carbonate (bleach activator) and sodium percarbonate (bleach). A preferred detergent composition (Ex 1) was formulated by addition of sodium 4-sulphophenyl 2-ethylhexyl carbonate (bleach activator according to the present invention), sodium percarbonate (bleach) and enzymes protease, lipase, amylase and mannanase to the control composition.

The formulations of control, comparative compositions (Comp A, Comp B) and preferred composition (Ex 1) is provided in Table 1. c) Washing protocol for determining SRI-values

For the determination of the SRI-values, a standard protocol was used, called the machine wash protocol.

Said machine wash protocol is as follows: (a) A set of 6 knitted cotton swatches and another set of 6 woven cotton swatches were taken. (b) Each woven cotton swatch was stained with tomato ketchup stain and each of the knitted cotton swatches were stained with lipstick stain. (c) Colour of the two stains on the cotton swatches were measured before washing to get AE*bw (before wash). (d) 7gpl of the control composition was added to a Miele Washing machine Softronic W4165. (e) A normal white wash cotton intensive cycle 1 hour 56 minutes was selected with water temperature of 40°C. The total wash liquor used was 6 litres. The water used had a hardness 24° French hardness. The wash load was 1.5 kg. (f) The wash load included the stained cotton swatches and two SBL soil strips and the liquor to cloth ratio was 4:1. The stained cotton swatches were not soaked before washing. (g) Post washing the cotton swatches was dried overnight. (h) The after wash reading of the stain on the 6 knitted cotton swatches and the 6 woven cotton swatches were recorded.

Similarly the stained cotton swatches were prepared and washed as described in the above steps (a) to (h) with comparative compositions (Comp A, Comp B) and preferred composition (Ex 1) and the reading of the swatches were taken before and after wash. d) Measurement of the delta SRI values

The delta SRI value after wash was determined as the difference between the absolute SRI value for a stained cotton swatch washed with the preferred or comparative composition and absolute SRI value for a stained cotton swatch washed with the control composition.

For preferred composition (Ex 1):

Delta SRI = (absolute SRI of stained cotton swatch washed with preferred composition) - (absolute SRI of stained cotton swatch washed with control composition).

For comparative composition: (Comp, Comp B)

Delta SRI = (absolute SRI of stained cotton swatch washed with comparative composition) - (absolute SRI of stained cotton swatch washed with control composition) A delta SRI value higher than the LSD (Least significant difference) value indicates a statistically significant difference between the absolute SRI values of stained swatch washed with the preferred composition or comparative composition and the absolute SRI value of stained swatch washed with control composition.

The delta SRI values of the cotton swatches stained with lipstick stain and with tomato ketchup stain after washing with control, comparative, preferred compositions with the machine wash protocol described above are provided in Table 2.

Tablel

Table 2

The results in Table 2 clearly shows that the delta SRI of the preferred compositions (Ex 1) having a specific bleach activator according to the present invention and enzyme shows statistically significant improvement in removal of lipstick stain and tomato ketchup stain when compared to the control composition and provides improved performance as compared to the comparative compositions (Comp A, Comp B).

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as, an acknowledgement or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Claims

The claims defining the invention are as follows: 1 A detergent composition comprising: (i) a precipitating builder; (ii) 0 to 5 wt% of zeolites or a phosphate sequestering builder or mixtures thereof; (iii) 2 to 80 wt% surfactant; wherein the composition comprises: (i) an enzyme; and, (ii) a bleach activator of the general formula (I)

m and where R is an alkyl group with 6 to 10 carbon atoms and M+ is a cation, wherein the enzyme is a mixture of lipase, mannanase, amylase and protease enzymes.
2 A composition as claimed in claim 1 wherein the alkyl group R is selected from n-hexyl or n-octyl or 2-ethylhexyl.
3 A composition as claimed in claim 1 or 2 wherein the cation M+ is sodium or potassium.
4 A composition as claimed in claims 1 to 3 wherein the bleach activator is sodium 4-sulphophenyl 2-ethylhexyl carbonate.
5 A composition as claimed in claim 1 wherein the precipitating builder is sodium carbonate.
6 A composition as claimed in any one of the preceding claims wherein the surfactant is anionic, non-ionic, amphoteric, zwitterionic or mixtures thereof.
7 A composition as claimed in any one of the preceding claims further comprising a soil release polymer.
8 A method of bleaching a bleachable substrate comprising the steps of: (i) applying to the substrate a neat or diluted form of the composition as claimed in any one of the preceding claims 1 to 7; and, (ii) rinsing the substrate.
9 Use of a detergent composition as claimed in any one of the preceding claims for effective removal of tough hydrophobic stains.