PROCESSES OF SOAKING FABRICS

Abstract: The present invention relates to a process of bleaching a fabric which comprises contacting the fabric with a composition comprising a peroxy carboxylic acid, soaking the fabric and subsequently rinsing the fabric with water.

Description: PROCESSES OF SOAKING FABRICS Technical Field The present invention relates to a process of bleaching fabrics with a composition comprising a peroxy carboxylic acid. Background of the invention Detergent compositions suitable for laundry applications are well known in the art. It is also known that detergent compositions relying on hypochlorite as a bleaching agent can be preferred over oxygen bleaches, mainly for performance reasons, especially at lower temperatures. Typically used oxygen bleaches are the oxygen bleach precursors perborate or percarbonate that react with an activator species to produce hydrogen peroxide. However, there are some limitations to the convenience of hypochlorite bleaches. In particular, it is well known from consumers that hypochlorite bleaching may cause yellowing and/or damage of the fabrics which are being bleached. This holds particularly true for synthetic fabrics and indeed there is a standing prejudice against using hypochlorite bleaches on synthetic fibers, as evidenced by warnings on labels of commercially available hypochlorite bleaches. Also, a variety of fabrics made of or containing synthetic fibers are labeled by their manufacturers as non-bleachable. The manufacturer is therefore faced with achieving a balance between cleaning performance and fabric and/or colour damage. The Applicant has identified a bleaching agent, peroxy carboxylic acid, that is milder than hypochlorite, yet still provides improved cleaning performance versus the oxygen bleach precursor bleaching agents currently used in most fully formulated detergent compositions. Peroxy carboxylic acids are known in the art for example EP 435 379. However, despite the apparent suitability of this bleach, it has been found that cleaning performance is occasionally not sufficient to meet consumer expectations. It is therefore an object of the present invention to address the issues mentioned above, namely those of providing improved overall stain removal performance on a wide range of stains as well as improved bleaching performance when bleaching fabrics while being safe to the fabrics bleached and to colours. We have found that these issues are efficiently addressed when soiled (coloured) fabrics are bleached with the composition described in the present invention. Indeed, it has been found that even when the process of bleaching fabrics according to the present invention includes the step of diluting the composition in water, improved overall stain removal performance and improved bleaching performance is delivered. Advantageously, the bleaching processes described herein provide effective bleaching performance and effective stain removal performance even when relatively short soaking time conditions are used, for example below 30 minutes, more preferably below 10 minutes and most preferably below 5 minutes. Furthermore, the bleaching processes described herein even provide effective bleaching performance and effective stain removal performance when soaking is carried out in cold water, for example 4°C. Thus, the present invention provides a process of bleaching fabrics that best fits the needs of today's consumers, i.e. a process of bleaching fabrics that provides effective bleaching and stain removal performance in reduced time periods and/or by using cold water. Advantageously, the laundry bleaching operations according to the present invention are safe to the fabrics per se and/or fabrics colours. Indeed, it has been surprisingly been found that when formulating the composition used in the salt and process as described herein, the safety (both fabric safety and colour safety) delivered to the fabrics bleached therewith according to the process of the present invention is improved as compared to formulating the same ingredients in a granular composition. Summary of the invention The present invention encompasses a process of bleaching a fabric comprising the steps of : (a) contacting the fabric with a bleaching composition comprising a pre-formed peroxy carboxylic acid and from 0.01 to less than 5% surfactant; (b) soaking the fabric in the composition for between 1 minute and 24 hours; and (c) rinsing the fabric with water. Detailed Description The process of bleaching fabrics: The present invention encompasses a process of bleaching fabrics as described herein after. By "fabrics", it is to be understood any types of fabrics including for example clothes, curtains, drapes, bed linens, bath linens, table cloths, sleeping bags, tents, upholstered furniture and the like. The process of bleaching fabrics herein is suitable for both natural fabrics and synthetic fabrics. By "natural" fabrics, it is meant fabrics made of cotton, viscose, linene, silk and/or wood. By "synthetic" fabrics, it is meant those made of synthetic fibers like polymeric fibers (polyamide, polyester, lycra® and elasthane®), and those made of both natural and synthetic fibers. The process of bleaching fabrics according to the present invention comprises the steps of: (a) contacting said fabrics with a bleaching composition comprising a pre-formed peroxy carboxylic acid (hereafter referred to as peracid) and from 0.01 to less than 5% surfactant (b) soaking the fabric in the composition for between 1 minute and 24 hours; and; (c) rinsing the fabrics with water. In the process of bleaching fabrics of the present invention, the fabrics are left in contact with the composition comprising peracid (in the so-called "soaking step") for a period of time sufficient to bleach the, fabrics. This period of time typically ranges from 1 minute to 24 hours, preferably from 3 minutes to 12 hours and more preferably from 4 minutes to 6 hours. Advantageously, the process of bleaching according to the present invention provides effective bleaching performance and effective stain removal performance even upon shorter soaking time, typically below 1 hour, preferably below 20 minutes and more preferably from 4 minutes to 15 minutes. The composition may be diluted with water at a dilution level of up to 500 times its weight, preferably from 5 to 200 times and more preferably from 10 to 80 times. Such dilution may occur for instance in hand laundry applications as well as by the other means such as in washing machine. Although, the temperature of the bleaching process does have an influence on the stain removal performance and/or bleaching performance of the compositions used herein, effective stain removal performance and/or bleaching performance are even provided at low temperatures typically as low as 4°C. Typically, the bleaching process according to the present invention are carried out at a temperature of from 4°C to 60°C, preferably from 10°C to 50°C and most preferably from 15°C to 30°C. More particularly, these benefits can be seen not only at low temperatures but also under short soaking periods, typically below 20 minutes. It is also understood that by increasing the temperature the bleaching process can be accelerated, i.e. the time required to bleach a given soiled fabric is reduced. Surprisingly, the process of bleaching fabrics according to the present invention provides improved bleaching performance and improved overall stain removal performance, as compared to the same process where the bleaching composition used is a composition based on activated hydrogen peroxide at the same total level of bleaching agents. Also these benefits are obtained with the process of bleaching fabrics according to the present invention with short soaking time in both cold or hot aqueous baths. Indeed, effective bleaching performance is provided on a variety of bleachable soils, from hydrophobic to hydrophilic soils on both hydrophilic and hydrophobic fabrics. Effective bleaching performance herein also includes effective whiteness. Advantageously, the present invention provides not only effective bleaching performance but also overall effective stain removal performance on various types of stains including greasy stains (e.g., lipstick, tomato, make-up) and/or enzymatic stains (e.g. blood, choco pudding). If said fabrics are to be washed, i.e., with a conventional laundry detergent composition comprising at least one surfactant at greater than 5% by weight of detergent, said washing may be conducted at the same time as the soaking of said fabrics by the process of the present invention. Alternatively washing may be conducted before or after the fabrics have been soaked in the bleaching composition according to the process of the present invention. In a preferred embodiment herein the fabrics are preferably washed in a separate step from the process of the present invention to get optimum bleaching and stain removal performance. Indeed, conducting the process herein and washing with a detergent composition in the same step may cause chemical interaction between the peracid and the conventional detergent ingredients typically present in a conventional detergent composition, i.e. enzymes, surfactants and the like and thus may reduce the bleaching performance and/or overall stain removal performance. In a highly preferred embodiment of the present invention, it is preferred to perform the bleaching process herein after said fabrics have been first washed with a conventional laundry detergent composition. Indeed, it has been observed that performing the process according to the present invention after washing the fabrics with a detergent composition provides superior bleaching and stain removal performance with less energy and detergent than if the process was performed before washing. The soaking process as described herein may be performed by hand using a suitable vessel. A suitable vessel may be any that can vessel or container that has enough capacity to hold the fabrics, bleaching composition and dilution water if required. An example of such a vessel may be a bucket, sink, bath, bowl etc. Alternatively the soaking process may be performed in a laundry washing machine. Where a washing steps is also preferred, the washing step may also be performed by hand in a suitable vessel or in a laundry washing machine. It has further been found that reduced colour damage (i.e., colour change and/or decolouration) and reduced tensile strength loss are observed when bleaching the fabrics according to the present invention. The reduced tensile strength loss and reduced colour damage are observed even if the composition is left to soak with the composition as described herein for prolonged periods of time before rinsing the fabrics, e.g. 24 hours. Actually, formulating the composition at a pH below 7, prevents the decomposition (oxidation) of dyes generally present on the surface of coloured fabrics such as bleach sensitive dyes and/or metallized dyes including copper-formazan dyes and/or metal-azo dyes, when the fabrics are bleached therewith according to the process herein. The tensile strength in a fabric may be measured by stretching said fabric until it breaks. The force needed to break the fabric is the "Ultimate Tensile Stress" and may be measured with a stress-strain INSTRON ® machine available from INSTRON. The loss of tensile strength is the difference between the tensile strength of a fabric taken as a reference, e.g. a fabric which has not been bleached, and the tensile strength of the same fabric after having been bleached with a composition of the present invention. A tensile strength loss of zero means that no fabric damage is observed. The colour safety can be evaluated visually by comparing side by side fabrics soaked with a composition of the present invention and a reference composition. Differences and graduations in colour can be visually assessed and ranked according to Panel Score Units (PSU) using any suitable scale. PSU data can be handled statistically using conventional techniques. Alternatively, various types of optical apparatus and procedures can be used to assess the improvement in colour safety afforded by the present invention. For example when evaluating colour safety on fabrics measurements with Hunterlab colour Quest 45/0 apparatus can be used. An advantage of the compositions suitable for use in the process of bleaching fabrics according to the present invention is that they are physically and chemically stable upon prolonged periods of storage. Chemical stability of these compositions may be evaluated by measuring the concentration of available oxygen at given storage time after having manufactured the compositions. By "chemically stable", it is meant herein that the compositions used herein comprising a peracid do not undergo more than 15% AvO loss, in one month at 25°C and preferably not more than 10%. Available oxygen (AvO) loss of a peracid containing composition can be measured by titration with potassium permanganate after reduction with a solution containing ammonium ferrous sulphate. Said stability test method is well known in the art and is reported, for example, on the technical information sheet of Curox^ commercially available from Interox. Alternatively peracid concentration can also be measured using a chromatography method described in the literature for peracids (F. Di Furia et al., Gas-liquid Chromatography Method for Determination of Peracids, Analyst, Vol 113, May 1988, p 793-795). By "physically stable" it is meant herein that no phase separation occurs in the compositions used herein for a period of 7 days at 50°C. The compositions used in the process of bleaching fabrics The compositions for use in the process of bleaching fabrics according to the present invention are preferably liquid compositions. As used herein "liquid" includes "pasty" compositions. These liquid compositions herein are preferably aqueous compositions, comprising water at a level of preferably 10 to 99%, more preferably from 50% to 98% by weight of the bleaching composition. These compositions according to the present invention have a pH below 7, preferably from 0.1 to 6.5, more preferably from 1 to 5, and most preferably from 2 to 4. Formulating these compositions in the acidic pH range is critical to the chemical stability of these compositions upon prolonged periods of storage before their use in the process of bleaching fabrics according to the present invention. The pH of these compositions may be adjusted by any acidifying or alkalinising agents known to those skilled in the art.. Examples of acidifying agents are organic acids such as citric acid and inorganic acids such as sulphuric acid, sulphonic acid and/or methanesulphonic acid. Examples of alkalinising agents are sodium hydroxide, potassium hydroxide and/or sodium carbonate. Pre-formed Peroxy Carboxylic Acid The compositions of the present invention comprise a pre-formed peroxy carboxylic acid (hereafter referred to as peracid). In a preferred embodiment of the present invention the peracid has the general formula X-R-C(O)OOH wherein R is a linear or branched alkyl chain having at least 1 carbon atom and X is hydrogen or a substituent group selected from the group consisting of alkyl, especially alkyl chains of from 1 to 24 carbon atoms, aryl, halogen, ester, ether, amine, amide, substituted phthalic amino, imide, hydroxide, sulphide, sulphate, sulphonate, carboxylic, heterocyclic, nitrate, aldehyde, phosphonate, phosphonic or mixtures thereof. More particularly the R group preferably comprises from 2 to 24 carbon atoms. Alternatively, the R group may be a branched alkyl chain comprising one or more side chains which comprise substituent groups selected from the group consisting of aryl, halogen, ester, ether, amine, amide, substituted phthalic amino, imide, hydroxide, sulphide, sulphate, sulphonate, carboxylic, heterocyclic, nitrate, aldehyde, ketone or mixtures thereof. In a preferred peracid the X group, according to the above general formula, is a phthalimido group. Thus, particularly preferred peracids are those having general formula: where R is C1-20 alkyl group and where A, B, C and D are independently either hydrogen or substituent groups individually selected from the group consisting of alkyl, hydroxyl, nitro, halogen, amine, ammonium, cyanide, carboxylic, sulphate, sulphonate, aldehydes or mixtures thereof. In a preferred aspect of the present invention R is an alkyl group having from 3 to 12 carbon atoms, more preferably from 5 to 9 carbon atoms. Preferred substituent groups A, B, C and D are linear or branched alkyl groups having from 1 to 5 carbon atoms, but more preferably hydrogen. Preferred peracids are selected from the group consisting of phthaloyl amido peroxy hexanoic acid (also known as phthaloyl amido-peroxy caproic acid), phthaloyl amido peroxy heptanoic acid, phthaloyl amido peroxy octanoic acid, phthaloyl amido peroxy nonanoic acid, phthaloyl amido peroxy decanoic acid and mixtures thereof. Even more preferred peracids are any of having general formula: o O wherein R is selected from C1-4 alkyl and n is an integer of from 1 to 5. In a particularly preferred aspect of the present invention the peracid has the formula such that R is CH 2 and n is 5 i.e. phthaloyl amido-peroxy caproic acid or PAP. The peracid is preferably used as a substantially water-insoluble solid or wetcake and is available from Ausimont under the trade name Euroco. The peracid may be present in the composition at a level of from 0.1% to 10% more preferably 0.5% to 8% and most preferably 1 % to 6%. Alternatively the peracid may be present at a much higher level of for example 10% to 40%, more preferably from 15% to 30%, most preferably from 20% to 25% Surfactants The compositions suitable for use in the process of bleaching fabrics herein comprise a surfactant at a level of from 0.01 to less than 5%. The surfactant is selected from nonionic surfactants, anionic surfactants, cationic surfactants, zwitterionic surfactants and/or amphoteric surfactants. Typically, the compositions according to the present invention comprise from 0.01 to less than 5%, preferably from 0.1 % to 4 % and more preferably from 1% to 3% surfactant by weight of the composition. Suitable anionic surfactants for use in the compositions herein include water- soluble salts or acids of the formula ROSO3M wherein R preferably is a C<\o- C24 hydrocarbyl, preferably an alkyl or hydroxyalkyl having a C10-C20 alkyl component, more preferably a C12-C18 alkyl or hydroxyalkyl, and M is H or a cation, e.g., an alkali metal cation (e.g., sodium, potassium, lithium), or ammonium or substituted ammonium (e.g., methyl-, dimethyl-, and trimethyl ammonium cations and quaternary ammonium cations, such as tetramethyl- ammonium and dimethyl piperdinium cations and quaternary ammonium cations derived from alkylamines such as ethylamine, diethylamine, triethylamine, and mixtures thereof, and the like). Typically, alkyl chains of C-J2-16 are preferred for lower wash temperatures (e.g., below about 50°C) and C1 -18 alkyl chains are preferred for higher wash temperatures (e.g., above about 50°C). Other suitable anionic surfactants for use herein are water-soluble salts or acids of the formula RO(A) m SO3M wherein R is an unsubstituted C10-C24 alkyl or hydroxyalkyl group having a C10- 24 alkyl component, preferably a C12- 20 alkyl or hydroxyalkyl, more preferably C12-C18 alkyl or hydroxyalkyl, A is an ethoxy or propoxy unit, m is greater than zero, typically between about 0.5 and about 6, more preferably between about 0.5 and about 3, and M is H or a cation which can be, for example, a metal cation (e.g., sodium, potassium, lithium, calcium, magnesium, etc.), ammonium or substituted-ammonium cation. Alkyl ethoxylated sulfates as well as alkyl propoxylated sulfates are contemplated herein. Specific examples of substituted ammonium cations include methyl-, dimethyl-, trimethyl-ammonium and quaternary ammonium cations, such as tetramethyl-ammonium, dimethyl piperdinium and cations derived from alkanolamines such as ethylamine, diethylamine, triethylamine, mixtures thereof, and the like. Exemplary surfactants are C12-C18 alkyl polyethoxylate (1.0) sulfate, C-12-C < |8E(1.0)M), C12-C18 alkyl polyethoxylate (2.25) sulfate, C12- C-18E(2.25)M), C12-C18 alkyl polyethoxylate (3.0) sulfate C < |2-C < |8 E ( 3 - 0 )- and C-12-C18 alkyl polyethoxylate (4.0) sulfate Ci2-CiδE( -0)M), wherein M is conveniently selected from sodium and potassium. Other particularly suitable anionic surfactants for use herein are alkyl sulphonates including water-soluble salts or acids of the formula RSO3M wherein R is a C6-C22 linear or branched, saturated or unsaturated alkyl group, preferably a C-12-C18 alkyl group and more preferably a C14-C-16 alkyl group, and M is H or a cation, e.g., an alkali metal cation (e.g., sodium, potassium, lithium), or ammonium or substituted ammonium (e.g., methyl-, dimethyl-, and trimethyl ammonium cations and quaternary ammonium cations, such as tetramethyl-ammonium and dimethyl piperdinium cations and quaternary ammonium cations derived from alkylamines such as ethylamine, diethylamine, triethylamine, and mixtures thereof, and the like). Suitable alkyl aryl sulphonates for use herein include water- soluble salts or acids of the formula RSO3M wherein R is an aryl, preferably a benzyl, substituted by a C5-C22 linear or branched saturated or unsaturated alkyl group, preferably a C-12-C18 alkyl group and more preferably a C14-C16 alkyl group, and M is H or a cation, e.g., an alkali metal cation (e.g., sodium, potassium, lithium, calcium, magnesium etc) or ammonium or substituted ammonium (e.g., methyl-, dimethyl-, and trimethyl ammonium cations and quaternary ammonium cations, such as tetramethyl-ammonium and dimethyl piperdinium cations and quaternary ammonium cations derived from alkylamines such as ethylamine, diethylamine, triethylamine, and mixtures thereof, and the like). The alkylsulfonates and alkyl aryl sulphonates for use herein include primary and secondary alkylsulfonates and primary and secondary alkyl aryl sulphonates. By "secondary C6-C22 alkyl or C6-C22 alkyl aryl sulphonates", it is meant herein that in the formula as defined above, the SO3M or aryl-SO3M group is linked to a carbon atom of the alkyl chain being placed between two other carbons of the said alkyl chain (secondary carbon atom). For example C14-C16 alkyl sulphonate salt is commercially available under the name Hostapur ® SAS from Hoechst and C8-alkylsulphonate sodium salt is commercially available under the name Witconate NAS 8® from Witco SA. An example of commercially available alkyl aryl sulphonate is Lauryl aryl sulphonate from Su.Ma. Particularly preferred alkyl aryl sulphonates are alkyl benzene sulphonates commercially available under trade name Nansa® available from Albright&Wilson. Other anionic surfactants useful for detersive purposes can also be used herein. These can include salts (including, for example, sodium, potassium, ammonium, and substituted ammonium salts such as mono-, di- and triethanolamine salts) of soap, C8-C24 olefinsulfonates, sulfonated polycarboxylic acids prepared by sulfonation of the pyrolyzed product of alkaline earth metal citrates, e.g., as described in British patent specification No. 1 ,082,179, C8-C24 alkylpolyglycolethersulfates (containing up to 10 moles of ethylene oxide); alkyl ester sulfonates such as C-14.16 methyl ester sulfonates; acyl glycerol sulfonates, fatty oleyl glycerol sulfates, alkyl phenol ethylene oxide ether sulfates, paraffin sulfonates, alkyl phosphates, isethionates such as the acyl isethionates, N-acyl taurates, alkyl succinamates and sulfosuccinates, monoesters of sulfosuccinate (especially saturated and unsaturated C-12-C18 monoesters) diesters of sulfosuccinate (especially saturated and unsaturated C6-C14 diesters), sulfates of alkylpolysaccharides such as the sulfates of alkylpolyglucoside (the nonionic nonsulfated compounds being described below), branched primary alkyl sulfates, alkyl polyethoxy carboxylates such as those of the formula RO(CH 2 CH 2 O) k CH 2 COO-M + wherein R is a C 8 -C 22 alkyl, k is an integer from 0 to 10, and M is a soluble salt-forming cation. Resin acids and hydrogenated resin acids are also suitable, such as rosin, hydrogenated rosin, and resin acids and hydrogenated resin acids present in or derived from tall oil. Further examples are given in "Surface Active Agents and Detergents" (Vol. I and II by Schwartz, Perry and Berch). A variety of such surfactants are also generally disclosed in U.S. Patent 3,929,678, issued December 30, 1975, to Laughlin, et al. at Column 23, line 58 through Column 29, line 23 (herein incorporated by reference). Other particularly suitable anionic surfactants for use herein are alkyl carboxylates and alkyl alkoxycarboxylates having from 4 to 24 carbon atoms in the alkyl chain, preferably from 8 to 18 and more preferably from 8 to 16, wherein the alkoxy is propoxy and/or ethoxy and preferably is ethoxy at an alkoxylation degree of from 0.5 to 20, preferably from 5 to 15. Preferred alkylalkoxycarboxylate for use herein is sodium laureth 11 carboxylate (i.e., RO(C2H4θ)ιo-CH2COONa, with R= C12-C14) commercially available under the name Akyposoft® 100NV from Kao Chemical Gbmh. Suitable amphoteric surfactants for use herein include amine oxides having the following formula R1 R2R3NO wherein each of R1 , R2 and R3 is independently a saturated substituted or unsubstituted, linear or branched hydrocarbon chains of from 1 to 30 carbon atoms. Preferred amine oxide surfactants to be used according to the present invention are amine oxides having the following formula R1 R2R3NO wherein R1 is an hydrocarbon chain comprising from 1 to 30 carbon atoms, preferably from 6 to 20, more preferably from 8 to 16, most preferably from 8 to 12, and wherein R2 and R3 are independently substituted or unsubstituted, linear or branched hydrocarbon chains comprising from 1 to 4 carbon atoms, preferably from 1 to 3 carbon atoms, and more preferably are methyl groups. R1 may be a saturated substituted or unsubstituted linear or branched hydrocarbon chain. Suitable amine oxides for use herein are for instance natural blend C8-C10 amine oxides as well as C12-C16 amine oxides commercially available from Hoechst. Suitable zwitterionic surfactants for use herein contain both a cationic hydrophilic group, i.e., a quaternary ammonium group, and anionic hydrophilic group on the same molecule at a relatively wide range of pH's. The typical anionic hydrophilic groups are carboxylates and sulfonates, although other groups like sulfates, phosphonates, and the like can be used. A generic formula for the zwitterionic surfactants to be used herein is : R 1 -N + (R 2 )(R 3 )R4X- wherein R-| is a hydrophobic group; R2 is hydrogen, Ci-Cs alkyl, hydroxy alkyl or other substituted C-i-Cβ alkyl group; R3 is C^ -CQ alkyl, hydroxy alkyl or other substituted C-i-Cβ alkyl group which can also be joined to R2 to form ring structures with the N, or a Ci-Cβ carboxylic acid group or a C-i-Cρ sulfonate group; R4 is a moiety joining the cationic nitrogen atom to the hydrophilic group and is typically an alkylene, hydroxy alkylene, or polyalkoxy group containing from 1 to 10 carbon atoms; and X is the hydrophilic group which is a carboxylate or sulfonate group. Preferred hydrophobic groups R-j are aliphatic or aromatic, saturated or unsaturated, substituted or unsubstituted hydrocarbon chains that can contain linking groups such as amido groups, ester groups. More preferred R-| is an alkyl group containing from 1 to 24 carbon atoms, preferably from 8 to 18, and more preferably from 10 to 16. These simple alkyl groups are preferred for cost and stability reasons. However, the hydrophobic group R-| can also be an amido radical of the formula R a -C(O)-NH-(C(Rb)2)m- wherein R a is an aliphatic or aromatic, saturated or unsaturated, substituted or unsubstituted hydrocarbon chain, preferably an alkyl group containing from 8 up to 20 carbon atoms, preferably up to 18, more preferably up to 16, Rb is selected from the group consisting of hydrogen and hydroxy groups, and m is from 1 to 4, preferably from 2 to 3, more preferably 3, with no more than one hydroxy group in any (C(R b ) 2 ) moiety. Preferred R2 is hydrogen, or a C1-C3 alkyl and more preferably methyl. Preferred R3 is a C1-C4 carboxylic acid group or C1-C4 sulfonate group, or a C-1-C3 alkyl and more preferably methyl. Preferred R4 is (CH2) n wherein n is an integer from 1 to 10, preferably from 1 to 6, more preferably is from 1 to 3. Some common examples of betaine/sulphobetaine are described in U.S. Pat. Nos. 2,082,275, 2,702,279 and 2,255,082, incorporated herein by reference. Examples of particularly suitable alkyldimethyl betaines include coconut-dimethyl betaine, lauryl dimethyl betaine, decyl dimethyl betaine, 2-(N-decyl-N, N- dimethyl-ammonia)acetate, 2-(N-coco N, N-dimethylammonio) acetate, myristyl dimethyl betaine, palmityl dimethyl betaine, cetyl dimethyl betaine, stearyl dimethyl betaine. For example Coconut dimethyl betaine is commercially available from Seppic under the trade name of Amonyl 265®. Lauryl betaine is commercially available from Albright & Wilson under the trade name Empigen BB/L®. Examples of amidobetaines include cocoamidoethylbetaine, cocoamidopropyl betaine or C10-C14 fatty acylamidopropylene(hydropropylene)sulfobetaine. For example C10-C14 fatty acylamidopropylene(hydropropylene)sulfobetaine is commercially available from Sherex Company under the trade name "Varion CAS® sulfobetaine". A further example of betaine is Lauryl-immino-dipropionate commercially available from Rhone-Poulenc under the trade name Mirataine H2C-HA ®. Suitable cationic surfactants for use herein include derivatives of quaternary ammonium, phosphonium, imidazolium and sulfonium compounds. Preferred cationic surfactants for use herein are quaternary ammonium compounds wherein one or two of the hydrocarbon groups linked to nitrogen are a saturated, linear or branched alkyl group of 6 to 30 carbon atoms, preferably of 10 to 25 carbon atoms, and more preferably of 12 to 20 carbon atoms, and wherein the other hydrocarbon groups (i.e. three when one hydrocarbon group is a long chain hydrocarbon group as mentioned hereinbefore or two when two hydrocarbon groups are long chain hydrocarbon groups as mentioned hereinbefore) linked to the nitrogen are independently substituted or unsubstituted, linear or branched, alkyl chain of from 1 to 4 carbon atoms, preferably of from 1 to 3 carbon atoms, and more preferably are methyl groups. Preferred quaternary ammonium compounds suitable for use herein are non- chloride/non halogen quaternary ammonium compounds. The counterion used in said quaternary ammonium compounds are compatible with any peracid and are selected from the group of methyl sulfate, or methylsulfonate, and the like. Particularly preferred for use in the compositions of the present invention are trimethyl quaternary ammonium compounds like myristyl trimethylsulfate, cetyl trimethylsulfate and/or tallow trimethylsulfate. Such trimethyl quaternary ammonium compounds are commercially available from Hoechst, or from Albright & Wilson under the trade name EMPIGEN CM®. Amongst the nonionic surfactants, alkoxylated nonionic surfactants and especially ethoxylated nonionic surfactants are suitable for use herein. Particularly preferred nonionic surfactants for use herein are the capped alkoxylated nonionic surfactants as they have improved stability to the peracid. Suitable capped alkoxylated nonionic surfactants for use herein are according to the formula: R1 (O-CH 2 -CH 2 )n-(OR2)m-0-R3 wherein Ri is a C8-C24 linear or branched alkyl or alkenyl group, aryl group, alkaryl group, preferably R-| is a Cs-C^s alkyl or alkenyl group, more preferably a C10-C 5 alkyl or alkenyl group, even more preferably a C10-C15 alkyl group; wherein R2 is a C1-C10 linear or branched alkyl group, preferably a C2-C10 linear or branched alkyl group ; wherein R3 is a C-|-C-|o alkyl or alkenyl group, preferably a C1-C5 alkyl group, more preferably methyl; and wherein n and m are integers independently ranging in the range of from 1 to 20, preferably from 1 to 10, more preferably from 1 to 5; or mixtures thereof. These surfactants are commercially available from BASF under the trade name Plurafac®, from HOECHST under the trade name Genapol® or from ICl under the trade name Symperonic®. Preferred capped nonionic alkoxylated surfactants of the above formula are those commercially available under the tradename Genapol® L 2.5 NR from Hoechst, and Plurafac® from BASF. Optional ingredients The compositions used in the process of bleaching fabrics according to the present invention may comprise a variety of optional ingredients such chelating agents, radical scavengers, antioxidants, other stabilisers, builders, soil suspenders, polymeric soil release agents, catalysts, dye transfer agents, solvents, suds controlling agents, brighteners, perfumes, pigments, dyes and the like. Chelating agents The compositions suitable for use in the process of bleaching fabrics herein may comprise a chelating agent as a preferred optional ingredient. Suitable chelating agents may be any of those known to those skilled in the art such as the ones selected from the group comprising phosphonate chelating agents, amino carboxylate chelating agents, other carboxylate chelating agents, polyfunctionally-substituted aromatic chelating agents, ethylenediamine N,N'- disuccinic acids, or mixtures thereof. The presence of chelating agents contribute to further enhance the chemical stability of the compositions. A chelating agent may be also desired in the compositions herein as it allows to increase the ionic strength of the compositions and thus their stain removal and bleaching performance on various surfaces. Suitable phosphonate chelating agents for use herein may include alkali metal ethane 1 -hydroxy diphosphonates (HEDP), alkylene poly (alkylene phosphonate), as well as amino phosphonate compounds, including amino aminotri(methylene phosphonic acid) (ATMP), nitrilo t methylene phosphonates (NTP), ethylene diamine tetra methylene phosphonates, and diethylene triamine penta methylene phosphonates (DTPMP). The phosphonate compounds may be present either in their acid form or as salts of different cations on some or all of their acid functionalities. Preferred phosphonate chelating agents to be used herein are diethylene triamine penta methylene phosphonate (DTPMP) and ethane 1 -hydroxy diphosphonate (HEDP). Such phosphonate chelating agents are commercially available from Monsanto under the trade name DEQUEST®- Polyfunctionally-substituted aromatic chelating agents may also be useful in the compositions herein. See U.S. patent 3,812,044, issued May 21 , 1974, to Connor et al. Preferred compounds of this type in acid form are dihydroxydisulfobenzenes such as 1 ,2-dihydroxy -3,5-disulfobenzene. A preferred biodegradable chelating agent for use herein is ethylene diamine N,N'- disuccinic acid, or alkali metal, or alkaline earth, ammonium or substitutes ammonium salts thereof or mixtures thereof. Ethylenediamine N,N'- disuccinic acids, especially the (S,S) isomer have been extensively described in US patent 4, 704, 233, November 3, 1987, to Hartman and Perkins. Ethylenediamine N,N'- disuccinic acids is, for instance, commercially available under the tradename ssEDDS® from Palmer Research Laboratories. Suitable amino carboxylates for use herein include ethylene diamine tetra acetates, diethylene triamine pentaacetates, diethylene triamine pentaacetate (DTPA),N- hydroxyethylethylenediamine triacetates, nitrilotri-acetates, ethylenediamine tetrapropionates, triethylenetetraaminehexa-acetates, ethanol- diglycines, propylene diamine tetracetic acid (PDTA) and methyl glycine di-acetic acid (MGDA), both in their acid form, or in their alkali metal, ammonium, and substituted ammonium salt forms. Particularly suitable amino carboxylates to be used herein are diethylene triamine penta acetic acid, propylene diamine tetracetic acid (PDTA) which is, for instance, commercially available from BASF under the trade name Trilon FS® and methyl glycine di-acetic acid (MGDA). Further carboxylate chelating agents for use herein include salicylic acid, aspartic acid, glutamic acid, glycine, malonic acid or mixtures thereof. Another chelating agent for use herein is of the formula: wherein R-| , R2, R3, and R4 are independently selected from the group consisting of -H, alkyl, alkoxy, aryl, aryloxy, -CI, -Br, -NO2, -C(O)R', and -SO2R"; wherein R' is selected from the group consisting of -H, -OH, alkyl, alkoxy, aryl, and aryloxy; R" is selected from the group consisting of alkyl, alkoxy, aryl, and aryloxy; and R5, RQ, R7, and Rs are independently selected from the group consisting of -H and alkyl. Particularly preferred chelating agents to be used herein are amino aminotri(methylene phosphonic acid), di-ethylene-triamino-pentaacetic acid, diethylene triamine penta methylene phosphonate, 1 -hydroxy ethane diphosphonate, ethylenediamine N, N'-disuccinic acid, and mixtures thereof. Typically, the compositions suitable for use in the process of bleaching fabrics herein comprise up to 5% by weight of the total composition of a chelating agent, or mixtures thereof, preferably from 0.01 % to 1.5% by weight and more preferably from 0.01 % to 0.5%. Radical scavengers The compositions suitable for use in the process of bleaching fabrics herein may comprise a radical scavenger or a mixture thereof. Suitable radical scavengers for use herein include the well-known substituted mono and dihydroxy benzenes and their analogs, alkyl and aryl carboxylates and mixtures thereof. Preferred such radical scavengers for use herein include di-tert-butyl hydroxy toluene (BHT), hydroquinone, di-tert-butyl hydroquinone, mono-tert-butyl hydroquinone, tert-butyl- hydroxy anysole, benzoic acid, toluic acid, catechol, t-butyl catechol, benzylamine, 1 ,1 ,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl) butane, n-propyl- gallate or mixtures thereof and highly preferred is di-tert-butyl hydroxy toluene. Such radical scavengers like N-propyl-gallate may be commercially available from Nipa Laboratories under the trade name Nipanox S1 ®. Radical scavengers when used, are typically present herein in amounts ranging from up to 10% by weight of the total composition and preferably from 0.001 % to 0.5% by weight. The presence of radical scavengers may contribute to the chemical stability of the bleaching compositions herein as well as to the safety profile of these compositions. Test methods: The bleaching performance may be evaluated by the following test methods on various type of bleachable stains. A suitable test method for evaluating the bleaching performance on a soiled fabric under soaking conditions is the following: A composition according to the present invention is diluted with water typically at a dilution level of 1 to 100 ml/L, preferably 20 ml/L (composition :water), then the soiled fabrics are soaked in it for 20 minutes to 6 hours and then rinsed. Alternatively the bleaching composition can be used in a washing machine at a dilution level of typically at a dilution level of 1 to 100 ml/L (composition :water). In the washing machine the soiled fabrics are washed at a temperature of from 30° to 70°C for 10 to 100 minutes and then rinsed. The reference composition in this comparative test undergoes the same treatment. Soiled fabrics/swatches with for example tea, coffee and the like may be commercially available from E.M.C. Co. Inc.. The bleaching performance is then evaluated by comparing side by side the soiled fabrics treated with the composition used in the present invention with those treated with the reference, e.g., the same composition but comprising no bleach or a different bleach at equal bleaching agents total level. A visual grading may be used to assign difference in panel units (psu) in a range from 0 to 4. For stain removal performance on various stains the same test method is followed but on enzymatic and greasy stains. Examples Following liquid aqueous persulfate compositions were made by mixing the listed ingredients in the listed proportions (weight % unless otherwise specified). Compositions I II III IV V (% weight) Na alkylbenzene sulphonate - 1 - 1.5 - Linear alkyl sulfonate - 1 0.5 - C12-15alkyl 7 ethoxylated 1 Akyposoft 100 NV® - 2 _ PAP 3 2 4 1 20 Hydroxyethanediphosphonate 0.1 0.05 0.16 0.1 0.1 Perfume - 0.2 0.2 0.3 - brightener - 0.01 0.05 0.03 - xanthan gum 0.3 0.2 0.3 - 0.5 carbopol ETD 2691 0.2 - 0.1 - carbopol ETD 2623 - - - 0.3 - carboxylmethoxycellulose - 1 0.5 1 - Alkanizing / acidizing agent up to pH 3 3..99 2.5 3.5 4 4 Akyposoft 100 NV® is a C12-C14 alkyl ethoxy 10 carboxylate commercially available from Kao Chemicala Gmbh. Witkonate NAS 8® is an alkylsulphonate available from Witco AS HEDP is ethane 1 -hydroxy diphosphonate commercially available from Monsanto under the serie Dequest®. PAP is phthalimidoperoxyhexanoic acid available from Ausimont under the tradename Euroco® Carbopol®ETD 2623 and 2991 are polymers available from BFGoodrich The following processes of bleaching fabrics will illustrate the present invention : Example 1 100 ml of a liquid peracid composition as exemplified above (compositions I to V) was diluted in 5L of water. Then soiled fabrics were contacted with the aqueous bath so obtained for 20 minutes before being rinsed with water. Example 2 200 ml of a liquid peracid composition as exemplified above (compositions I to V) was diluted in 5L of water. Then soiled fabrics were contacted with the aqueous bath so obtained for 20 minutes before being rinsed with water for 20 minutes. Example 3 300 ml of a liquid peracid composition as exemplified above (compositions I to V) was diluted in 5L of water. Then soiled fabrics were contacted with the aqueous bath so obtained for 20 minutes before being rinsed with water for 20 minutes. Example 4 100 ml of a liquid peracid composition as exemplified above (compositions I to V) was diluted in 5L of water. Then soiled fabrics were contacted with the aqueous bath so obtained for 1 hour before being rinsed with water for 20 minutes. Example 5 100 ml of a liquid peracid composition as exemplified above (compositions I to V) was diluted in 5L of water. Then soiled fabrics were contacted with the aqueous bath so obtained for 6 hours before being rinsed with water for 20 minutes. Example 6 100 ml of a liquid peracid composition as exemplified above (compositions I to V) was diluted in 5L of water. Then soiled fabrics were contacted with the aqueous bath so obtained for 24 hours before being rinsed with water for 20 minutes. Example 7 100 ml of a liquid peracid composition as exemplified above (compositions I to V) was diluted in 5L of water. Then soiled fabrics were contacted with the aqueous bath so obtained for 1 hour before being rinsed with water for 20 minutes. Finally the fabrics so bleached were contacting for 1 hour with 40g of Dash Futur® diluted in 5L of water and subsequently rinsed with water. Example 8 140 ml of Ariel a mano® were diluted with 5 liters of water. The soiled fabrics were contacted to the soaking solution so obtained for 1 hour and subsequently rinsed. Then 100 ml of a liquid peracid composition as exemplified above (compositions I to V) was diluted in 5L of water. Then the fabrics were contacted with the aqueous bath so obtained for 1 hour before being rinsed with water for 20 minutes. Example 9 100 ml of a liquid peracid-containing composition as exemplified above (compositions I to V) was diluted in 5L of water to obtain an aqueous bath to which the soiled fabrics were contacted for 20 minutes. The fabrics were then rinsed for 2 minutes than washed in a washing machine (e.g. San Giorgio 352 ZX®, main cycle) with 225g of Dash Futur®. All the above processes provide excellent bleaching performance as well as effective stain removal performance when bleaching fabrics while being safe to the fabrics and the colours.

Claims: Claims 1. A process of bleaching a fabric comprising the steps of: (a) contacting the fabric with a bleaching composition comprising a pre-formed peroxy carboxylic acid and from 0.01 to less than 5% surfactant; (b) soaking the fabric in the composition from between 1 minute and 24 hours; and; (c) rinsing the fabric with water. 2. A process according to claim 1 wherein the peroxy carboxylic acid has general formula: where R is C1-20 alkyl group and where A, B, C and D are independently either hydrogen or substituent groups individually selected from the group consisting of alkyl, hydroxyl, nitro, halogen, amine, ammonium, cyanide, carboxylic, sulphate, sulphonate, aldehydes or mixtures thereof. 3. A process according to any preceding claim wherein the peroxy carboxylic acid has general formula: o o wherein R is C-ι -4 and n is an integer of from 1 to 5. 4. A process according to claim 3 wherein the pre-formed peroxy carboxylic acid the formula where R is CH 2 and n is 5. 5. A process according to any preceding claim comprising one or more surfactants if selected from either anionic or nonionic surfactants or mixtures thereof. 6. A process according to any preceding claim wherein the composition is diluted with water at a dilution level up to 500 times its weight. 7. A process according to any preceding claim wherein the pH of the composition is less than 7. 8. A process according to any preceding claim wherein the fabric is washed with a laundry detergent composition comprising surfactant at a level of greater than 5% by weight of the detergent composition, before, after or at the same time as the fabric is contacted with the bleaching composition. 9. A process according to any of the preceding claims performed by hand in a suitable vessel or in a laundry washing machine.

Inventors: DI CAPUA GLORIA, DRESCO PIERRE ANTOINE, SCIALLA STEFANO, DI CAPUA, GLORIA, DRESCO, PIERRE, ANTOINE, SCIALLA, STEFANO
Applicants: CAPUA GLORIA DI, DRESCO PIERRE ANTOINE, PROCTER & GAMBLE, SCIALLA STEFANO, DI CAPUA, GLORIA, DRESCO, PIERRE, ANTOINE, SCIALLA, STEFANO, THE PROCTER & GAMBLE COMPANY
Application year: 1999
Main classification: C11D3
IPC codes: C11D3, C11D7, C11D11, D06L3