EP0095904B1

EP0095904B1 - Detergent liquors and compositions for use therein

Info

Publication number: EP0095904B1
Application number: EP83303058A
Authority: EP
Inventors: Frederick Edward Hardy; Michael Crombie Addison; John George Bell
Original assignee: Procter and Gamble Ltd; Procter and Gamble Co
Current assignee: Procter and Gamble Ltd; Procter and Gamble Co
Priority date: 1982-06-01
Filing date: 1983-05-27
Publication date: 1986-09-03
Also published as: JPS5930900A; ATE21930T1; JPH051320B2; DE3365840D1; EP0095904A1

Abstract

Detergent liquors, and compositions for their production, are provided in which acetylated aldohexopyranoses and -pyranosides are employed as peroxybleach precursors in combination with inorganic perhydrate salts, the molar ratio of perhydrate to aldohexopyranose or -pyranoside being >/= 12:1 and the liquor starting pH being > 9,5, whereby >/= 50% of the available acetyl groups are perhydrolysed.

Description

This invention relates to laundry wash liquors and detergent compositions for use therein, capable of removing oxidisable stains from fabrics washed therein at temperatures at or below 60°C. More particularly the invention relates to wash liquors containing mixtures of inorganic peroxygen bleaches of the perhydrate type and certain acetylated sugars and their derivatives serving as organic peroxy bleach precursors, which mixtures can be made to deliver improved bleaching performance under defined conditions.
The use of organic peroxy bleach precursors together with peroxygen bleaches of the perhydrate type (i.e. alkali metal perborates, percarbonates, persilicates, perpyrophosphates and the like) for removing oxidisable stains at low temperatures (i.e. :⁵60'C) is well known in the detergent art. Furthermore the use of acetylated polyols, including acetylated mono- and di-saccharides as peroxy bleach precursors is also disclosed in the prior art, notably in British Patent No. 836,988 where fructose penta acetate, glucose penta acetate, glucose tetra acetate and sucrose octa acetate are taught for this purpose.
British Patent 836,988 discloses that the release of one mole of peracetic acid would be expected from glucose tetra acetate and two moles would be expected from glucose penta acetate. No predictions are given for other disclosed polyol esters but it is assumed that they would behave similarly and release one or two moles of peracetic acid under the conditions employed in British Patent 836 988.
Surprisingly it has now been found that under certain defined conditions of usage this limitation does not apply and that in consequence more efficient utilisation of this class of organic peroxy bleach precursor is possible. By more efficient utilisation is meant that more peroxy acid bleach can be obtained from the same weight of precursor or alternatively the same amount of peroxy acid can be obtained from a lesser amount of precursor, resulting in a corresponding improvement in cost effectiveness.
This finding is of particular importance insofar as the saccharide esters are derived from materials available in bulk which are not petroleum based, and which therefore constitute a potentially high volume source of organic peroxy acid bleaching agent, which is less subject to the cost inflation associated with chemicals derived wholly from petroleum sources.
According to the present invention there is provided a laundry wash liquor adapted for the removal of oxidisable stains, particularly at temperatures of less than 60°C, said liquor containing 0.1% to 2.0% by weight of a detergent composition comprising an organic surfactant present in an amount to give from 10 to 5000 ppm in solution, an inorganic peroxygen bleach of the perhydrate type, and a peracetic acid precursor comprising an acetylated aldohexopyranose or acetylated aidohexopyranoside containing acetyl groups on at least three adjacent carbon atoms, present in an amount to give from 10 to 1000 ppm in solution, said wash liquor having a starting pH of at least 9.5, said starting pH being defined as the pH of a 0.5 wt% solution of said composition measured at 20°C after all of the soluble components have dissolved and prior to the addition of any soiled fabrics wherein the inorganic peroxygen bleach is present in an amount of at least 8.5 millimoles/dm³, and wherein the ratio of the moles of available peroxygen in the perhydrate to the moles of acetylated aldohexopyranose or -pyranoside is ,12:1 whereby the percentage of the acetyl groups present in the acetylated aldohexopyranose or -pyranoside that are converted to peracetic acid is greater than 50%.
Preferably the precursor is a fully acetylated aldohexopyranose or aldohexopyranoside. Preferably also the molar ratio of perhydrate to sugar alcohol is .15:1 and the starting pH of the wash liquor is at least 10.0. A highly preferred acetylated aldohexopyranose is penta acetyl glucose (in either alpha- or beta-form, or mixtures thereof), and preferred aldohexopyranosides include octa acetyl lactose and octa acetyl sucrose.
The present invention in its broadest aspect requires the formation of a laundry wash liquor incorporating an organic surfactant, an inorganic peroxygen bleach of the perhydrate type and an acetylated aldohexopyranose or pyranoside containing acetyl groups on at least three adjacent carbon atoms, the liquor pH being at least 9.5 under the conditions defined above.
A wide range of organic surfactants are believed to e suitable i.e. anionic, nonionic, ampholytic, zwitterionic or cationic surfactants may be employed either alone or in admixture. For laundry purposes, detergents having an overall anionic or nonionic character are usually employed, such detergents being totally anionic, or mixtures of anionic and nonionic types or mixtures of anionic, nonionic and ampholytic types of mixtures of anionic, nonionic and cationic types.
The anionic surfactant may be any one or more of the materials used conventionally in laundry detergents. Suitable synthetic anionic surfactants are water-soluble salts of alkyl benzene sulphonates, alkyl sulphates, alkyl polyethoxy ether sulphates, paraffin sulphonates, alpha-olefin sulphonates, alpha-sulpho-carboxylates and their esters, alkyl glyceryl ether sulphonates, fatty acid monoglyceride sulphates and sulphonates, alkyl phenol polyethoxy ether sulphates 2-acyloxy alkane-1-sulphonate, and beta-alkyloxy alkane sulphonate.
A particularly suitable class of anionic surfactants includes water-soluble salts, particularly the alkali metal, ammonium and alkanolammonium salts or organic sulphuric reaction products having in their molecular structure an alkyl or alkaryl group containing from 8 to 22, especially from 10 to 20 carbon atoms and a sulphonic acid or sulphuric acid ester group. (included in the term "alkyl" is the alkyl portion of acyl groups). Examples of this group of synthetic detergents which form part of the detergent compositions of the present invention are the sodium and potassium alkyl sulphates, especially those obtained by sulphating the higher alcohols (C_B-₁₈) carbon atoms produced by reducing the glycerides of tallow or coconut oil and sodium and potassium alkyl benzene sulphonates, in which the alkyl group contains from 9 to 15, especially 11 to 13, carbon atoms, in straight chain or branched chain configuration, e.g. those of the type described in US-A-2,220,099 and 2,477,383 and those prepared from alkylbenzenes obtained by alkylation with straight chain chloroparaffins (using aluminium trichloride catalysis) or straight chain olefins (using hydrogen fluoride catalysis). Linear alkyl benzene sulphonates in which the alkyl group contains an average of about 11.8 carbon atoms (C11.S LAS) or an average of 13 carbon atoms (C,₃ LAS) are particularly preferred.
Other anionic detergent compounds herein include the sodium C₁₀-_1S alkyl glyceryl ether sulphonates, especially those ethers of higher alcohols derived from tallow and coconut oil; sodium coconut oil fatty acid monoglyceride sulphonates and sulphates; and sodium or potassium salts of alkyl phenol ethylene oxide ether sulphate containing 1 to 10 units of ethylene oxide per molecule and wherein the alkyl groups contain about 8 to about 12 carbon atoms.
Other useful anionic detergent compounds herein include the water-soluble salts or esters of alpha-sulphonated fatty acids containing from 6 to 20 carbon atoms in the fatty acid group and from 1 to 10 carbon atoms in the ester group; water-soluble salts of 2-acyloxy-alkane-1-sulphonic acids containing from 2 to 9 carbon atoms in the acyl group and from 9 to 23 carbon atoms in the alkane moiety; alkyl ether sulphates containing from 10 to 18, especially 12 to 16, carbon atoms in the alkyl group and from 1 to 12, especially 1 to 6, more especially 1 to 4 moles of ethylene oxide; water-soluble salts of olefin sulphonates containing from 12to 24, preferably 14to 16, carbon atoms, especially those made by reaction with sulphur trioxide followed by neutralization under conditions such that any sultones present are hydrolysed to the corresponding hydroxy alkane sulphonates; water-soluble salts of paraffin sulphonates containing from 8 to 24, especially 14 to 18 carbon atoms, and beta-alkyloxy alkane sulphonates containing from 1 to 3 carbon atoms in the alkyl group and from 8 to 20 carbon atoms in the alkane moiety.
The alkane chains of the foregoing non-soap anionic surfactants can be derived from natural sources such as coconut oil or tallow, or can be made synthetically as for example using the Ziegler or Oxo processes. Water solubility can be achieved by using alkali metal, ammonium or alkanolammonium cations; sodium is preferred. Suitable fatty acid soaps can be selected from the ordinary alkali metal sodium, potassium, ammonium, and alkylolammonium salts of higher fatty acids containing from 8 to 24, preferably from 10 to 22 and especially from 16 to 22 carbon atoms in the alkyl chain. Suitable fatty acids can be obtained from natural sources such as, for instance, from oil, soybean oil, castor oil, tallow, whale and fish oils, grease, lard and mixtures thereof. The fatty acids also can be synthetically prepared (e.g., by the oxidation of petroleum, or by hydrogenation of carbon monoxide by the Fischer-Tropsch process). Resin acids are suitable such as rosin and those resin acids in tall oil. Naphthenic acids are also suitable. Sodium and potassium soaps can be made by direct saponification of the fats and oils or by the neutralization of the free fatty acids which are prepared in a separate manufacturing process. Particularly useful are the sodium and potassium salts of the mixtures of fatty acids derived from tallow and hydrogenated fish oil.
Mixtures of anionic surfactants are particularly suitable herein, especially mixtures of sulphonate and sulphate surfactants in a weight ratio of from 5:1 to 1:5, preferably from 5:1 to 1:1, more preferably from 5: 1 to 1.5: 1. Especially preferred is a mixture of an alkyl benzene sulphonate having from 9 to 15, especially 11 to 13 carbon atoms in the alkyl radical the cation being an alkali metal preferably sodium; and either an alkyl sulphate having from 10 to 20, preferably 12 to 18 carbon atoms in the alkyl radical or an ethoxy sulphate having from 10 to 20, preferably 10 to 16 carbon atoms in the alkyl radical and an average degree of ethoxylation of 1 to 6, having an alkali metal cation, preferably sodium.
The nonionic surfactants useful in the present invention are condensates of ethylene oxide with a hydrophobic moiety to provide a surfactant having an average hydrophilic-lipophilic balance (HLB) in the range from 8 to 17, preferably from 9.5 to 13.5, more preferably from 10 to 12.5. The hydrophobic moiety may be aliphatic or aromatic in nature and the length of the polyoxyethylene group which is condensed with any particular hydrophobic group can be readily adjusted to yield a water-soluble compound having the desired degree of balance between hydrophilic and hydrophobic elements.
Examples of suitable nonionic surfactants include:

1: The polyethylene oxide condensates of alkyl phenol, e.g. the condensation products of alkyl phenols having an alkyl group containing from 6 to 12 carbon atoms in either a straight chain or branched chain configuration, with ethylene oxide, the said ethylene oxide being present in amounts equal to 3 to 30, preferably 5 to 14 moles of ethylene oxide per mole of alkyl phenol. The alkyl substituent in such compounds may be derived, for example, from polymerised propylene, di-isobutylene, octene and nonene. Other examples include dodecylphenol condensed with 9 moles of ethylene oxide per mole of phenol; dinonylphenol condensed with 11 moles of ethylene oxide per mole of phenol; nonylphenol and di-isooctylphenol condensed with 13 moles of ethylene oxide.
2. The condensation product of primary or secondary aliphatic alcohols having from 8 to 24 carbon atoms, in either straight chain or branched chain configuration, with from 2 to 40 moles, preferably 2 to 9 moles of ethylene oxide per mole of alcohol. Preferably, the aliphatic alcohol comprises between 9 and 18 carbon atoms and is ethoxylated with between 2 and 9, desirably between 3 and 8 moles of ethylene oxide per mole of aliphatic alcohol. The preferred surfactants are prepared from primary alcohols which are either linear (such as those derived from natural fats or, prepared by the Ziegler process from ethylene, e.g. myristyl, cetyl, stearyl alcohols), or partly branched such as the Lutensols, Dobanols and Neodols which have about 25% 2-methyl branching (Lutensol being a Trade Name of BASF, Dobanol and Neodol being Trade Names of Shell), or Synperonics, which are understood to have about 50% 2-methyl branching (Synperonic is a Trade Name of I.C.I.) or the primary alcohols having more than 50% branched chain structure sold under the Trade Name Lial by Liquichimica. Specific examples of nonionic surfactants falling within the scope of the invention include Dobanol 45-4, Dobanol 45-7, Dobanol 45-9, Dobanol 91-3, Dobanol 91-6, Dobanol 91-8, Synperonic 6, Synperonic 14, the condensation products of coconut alcohol with an average of between 5 and 12 moles of ethylene oxide per mole of alcohol, the coconut alkyl portion having from 10 to 14 carbon atoms, and the condensation products of tallow alcohol with an average of between 7 and 12 moles of ethylene oxide per mole of alcohol, the tallow portion comprising essentially between 16 and 22 carbon atoms. Secondary linear alkyl ethoxylates are also suitable in the present compositions, especially those ethoxylates of the Tergitol series having from 9 to 15 carbon atoms in the alkyl group and up to 11, especially from 3 to 9, ethoxy residues per molecule.
3. The compounds formed by condensing ethylene oxide with a hydrophobic base formed by the condensation of propylene oxide with propylene glycol. The molecular weight of the hydrophobic portion generally falls in the range of 1500 to 1800. Such synthetic nonionic detergents are available on the market under the Trade Name of "Pluronic" supplied by Wyandotte Chemicals Corporation.

Especially preferred nonionic surfactants for use herein are the C₉-C,₅ primary alcohol ethoxylates containing 3-8 moles of ethylene oxide per mole of alcohol, particularly the C₁₂-C₁₅ primary alcohols containing 6-8 moles of ethylene oxide per mole of alcohol.
Within the nonionic class of surfactants, the semipolar type, represented by amine oxides, sulphoxides and phosphine oxides, are also useful. Suitable amine oxides have the general formula I
wherein R is a linear or branched alkyl or alkenyl group having 8 to 20 carbon atoms, each R¹ is independently selected from C_1-4 alkyl and ―(C_nH_2nO)_mH where i is an integer from 1 to 6, j is 0 or 1, n is 2 or 3 and m is from 1 to 7, the sum total of C_nH_2nO groups in a molecule being no more than 7.
In a preferred embodiment R has from 10 to 14 carbon atoms and each R¹ is independently selected from methyl and ―(C_nH_2nO)_mH wherein m is from 1 to 3 and the sum total of C_nH_2nO groups in a molecule is no more than 5, preferably no more than 3. In a highly preferred embodiment, j is 0 and each R¹ is methyl, and R is C₁₂-C₁₄ alkyl.
Another suitable class of amine oxide species is represented by bis-amine oxides having the following substituents.

j: 1
R: tallow C₁₆―C₁₈ alkyl; palmityl; oleyl; stearyl
R₁: hydroxyethyl
i: 2 or 3

₁₆

₁₈

Ampholytic detergents include derivatives of aliphatic or aliphatic derivatives of heterocyclic secondary and tertiary amines in which the aliphatic moiety can be straight chain or branched and wherein one of the aliphatic substituents contains from 8 to 18 carbon atoms and at least one aliphatic substituent contains an anionic water-solubilizing group.
Examples of compounds falling within this definition are sodium 3-(dodecylamino)-propionate, sodium 3-(dodecylamino) propane-1-suiphonate, sodium 2-(dodecylamino)ethyl sulphate, sodium 2-(dimethylamino)octadecanoate, disodium 3-(N-carboxymethyl-dodecylamino)propane-1-sulphonate, disodium octadecyl-iminodiacetate, sodium 1-carboxymethyl-2-undecylimidazole, and sodium N,N-bis(2-hydroxyethyl)-2-sulfato-3-dodecoxypropylamine. Sodium 3-(dodecylamino)-propane-1-sulphonate is preferred.
Zwitterionic detergents include derivatives of aliphatic quaternary ammonium, phosphonium and sulphonium compounds in which the aliphatic moieties can be straight chain or branched, and wherein one of the aliphatic substituents contains from 8 to 18 carbon atoms and one contains an anionic water-solubilizing group.
Cationic surfactants useful in the present invention can be broadly defined as quaternary ammonium compounds having the general formula:
wherein R² is a linear or branched alkyl, alkenyl or alkaryl group having 8 to 16 carbon atoms and each R³ is independently selected from C_1-4 alkyl, C_1-4 alkaryl and-(C_nH_2nO)_m wherein i is an integer from 1 to 6, j is 0 or 1, n is 2 or 3 and m is from 1 to 7, the sum total of C_nH_2nO groups in a molecule being no more than 7, and wherein Z represents a counteranion in number to give electrical neutrality.
In a preferred embodiment, R has from 10 to 14 carbon atoms and each R³ is independently selected from methyl and (C_nH_2nO)_mH wherein m is from 1 to 3 and the sum total of C_nH_2nO groups in a molecule is no more than 5, preferably no more than 3. In a highly preferred embodiment j is 0, R³ is selected from methyl, hydroxyethyl and hydroxypropyl and R² is C₁₂-C₁₄ alkyl. Particularly preferred surfactants of this class include C₁₂ alkyl trimethylammonium salts, C₁₄ alkyltrimethylammonium salts, coconutalkyltrimethyl- ammonium salts, coconutalkyldimethyl-hydroxyethylammonium salts, coconutalkyldimethyl- hydroxy-propylammonium salts, and C₁₂ alkyldihydroxyethylmethyl ammonium salts.
Another group of useful cationic compounds are the diammonium salts of formula II in which j is 1, R is C₁₂-C,₄ alkyl, each R³ is methyl, hydroxyethyl or hydroxypropyl and i is 2 or 3. In a particularly preferred surfactant of this type, R is coconut alkyl, R³ is methyl and i is 3.
Preferred anionic surfactants are linear alkyl benzene sulphonates in which the alkyl group has from 11 to 15 carbon atoms, two highly preferred examples having an average of 11.8 carbon atoms and 13 carbon atoms respectively in the alkyl group. Other preferred anionic surfactants are the alkyl sulphates particularly those having between 14 and 18 carbon atoms in the alkyl chain. Mixtures of alkyl benzene sulphonates and alkyl sulphates are also highly preferred.
Nonionic surfactants preferred for use in the invention are the C₁₂-C₁₅ primary alcohols condensed with an average of from 5 to 7 moles of ethylene oxide per mole of alcohol. The alkyl groups may be unbranched as in groups derived from natural fats and oils, or may be branched to different degrees as in synthetically derived materials.
An example of a suitable anionic-nonionic surfactant mixture is disclosed in European Patent Application No. 81301983.3 (Publication No. 0040038). Exemplary anionic-nonionic-cationic mixtures are disclosed in European Patent Application No. 78200050.2 (Publication No. 0000225). In the mixtures of Application No. 78200050.2, the surfactant system contains anionic and cationic surfactants in an equivalent ratio of at least 1:1, the weight ratio of anionic:cationic surfactants is ≤5:1 and the weight ratio of nonionic to cationic surfactants is in the range from 100:1 to 2:3. Combinations of anionic, ethoxylated nonionic, semipolar amine oxide and cationic surfactants are disclosed in European Patent Application No. 83200064.0 filed 14th January, 1983 (pub. 10.08.83; No. 85448).
The laundry liquors of the present invention contain from 10-5000 parts per million, more preferably from 100 to 1500 parts per million of surfactant. In the detergent composition aspect of the invention, the level of surfactant in the composition lies in the range from 1 to 25%, preferably from 5 to 15% by weight, such compositions being employed at levels of from 0.1% to 2.0% by weight of the liquor.
The second components of the laundry liquor is an inorganic peroxygen bleach of the perhydrate type which is present at a level of at least 8.5 millimoles/dm³ corresponding, e.g., to 1300 ppm sodium perborate tetrahydrate. The wash liquor can contain up to 7000 ppm of perhydrate product expressed on the foregoing basis, but formulation and cost constraints normally limit the maximum level to a value less than this. If the perhydrate is added as part of a detergent composition of the type commercially available in Europe, or as part of an additive product intended for use under conventional European wash conditions, the level generally lies in the range from 1300 ppm to 3200 ppm, more usually in the range from 1500 ppm to 2000 ppm. However, if the perhydrate is added as part of a composition intended to be used in a concentrated washing process such as that disclosed in European Patent Application No. 82305942.3, Publication No. 0079234 (pub. 18.05.83), the level of perhydrate expressed as sodium perborate tetrahydrate may be in the range 3000-6000 ppm. For the purposes of this invention perhydrate type bleaches are defined as those having hydrogen peroxide associated with the molecule such as alkali metal perborates, percarbonates, persilicates and perpyrophosphates.
In the detergent composition of this invention the inorganic peroxygen bleach is present at a level of from 15% to 35% by weight, preferably from 15% to 25% by weight of the composition.
Preferred perhydrates are sodium perborate mono- and tetrahydrate and sodium percarbonate.
The ester-type peroxy bleach precursors of the present invention can be broadly defined as acetylated aldohexopyranoses or aldohexopyranosides containing at least three acetyl groups on adjacent carbon atoms. Preferably the aldohexopyranoses or aldopyranosides are fully acetylated.
Suitable acetylated aldohexopyranoses include penta acetyl glucose, penta acetyl galactose and penta acetyl mannose. Examples of aldohexopyranosides include galactopyranoside derivatives such as octa acetyl lactose and glucopyranosides such as octa acetyl sucrose and tetra acetyl alpha-C₁-C₁₂ alkyl glucosides such as alpha-methyl, alpha-butyl and alpha-lauryl glucoside. In general, all of the available hydroxyl groups are acetylated as this is convenient from a manufacturing standpoint and facilitates the most efficient use of the molecule, but the invention does not preclude the use of less than fully acetylated molecules.
As noted previously, this general class of materials is known as a source of acetyl groups for the production of peracetic acid when mixed with inorganic perhydrate salts. However, the literature appears to have considered peracetic acid formation from acetylated sugar-perhydrate salt mixtures largely, if not exclusively, in terms of the reactivities of individual acetate groups. In the case of acetylated aldohexopyranoses this can give rise to misleading predictions, as the reactivity of an acetate group is less important than its selectivity i.e. its ability to perhydrolyse rather than hydrolyse. Depending on the acidity of the alcohol group from which the acetate is derived, the ratio between hydrolysis and perhydrolysis can range from 10⁴:1 to 1:3x10².
The Applicants have found that certain acetylated aldohexopyranoses can be utilised more effectively, i.e. can be induced to provide more peracetic acid per mole than hitherto considered possible, if the molecules satisfy certain structural criteria which enhance the acidity of the substituent acetyl groups.
R. L. Wells, 'Linear Free Energy Relationships', (Academic Press 1968), pages 35-39 suggests the use of Taft substituent parameters (σ^*) as a means of gauging the acidifying effects of neighbouring polar groups on substituents attached to a carbonyl group. The following Table lists a number of substituents and their Taft values o^*.
The Applicants have found that, surprisingly, the above effects also hold true for substituents attached to a hydroxyl group in aldohexopyranoses and pyranosides. If the assumptions are made that the effect diminishes by 40% for each intervening carbon atom and that the effect of groups more than two carbon atoms distant can be ignored, estimations can be made of the potential number of acetyl groups that could be released from different acetylated aldohexopyranoses and pyranosides. On this basis, summation of the effects of the different influencing groups on a particular acetyl, to provide a Σσ* for that acetyl, leads to the following correlation.

Σσ*≥0.6 perhydrolysis favoured relative to hydrolysis.
0.6 >Σσ*≥0.4 perhydrolysis and hydrolysis equally favoured.
Σσ*≤0.4 hydrolysis favoured.

For the purposes of this correlation it is assumed that both OOH- and OH- concentration are not limiting with respect to the precursor concentration.
An example of a preferred acetylated aldohexopyranose to which this correlation applies is penta acetyl glucose. British Patent No. 836 988 identifies a mole of this material as being capable of producing two moles of peracetic acid and provides an illustrative detergent composition in which it is used at an unspecified alkaline pH and a molar ratio of sodium perborate to glucose ester of 2:1.
Application of the above described estimation technique to this acetylated polyol, whose structure is shown schematically below, provides a value for o* for each acetyl group as follows

If allowance is made for the change in α* values as each acetyl group is released from the molecule, then the estimated No. of peracetic acid molecules/mole of penta acetyl glucose is 3.5. In an experiment run to check this hypothesis the No. found at pH 11.5 and perhydrate:penta acetyl glucose molar ratio of 15:1, was 3.4.
The conversion of acetyl groups to peracetic acid can be expressed as a conversion efficiency i.e. as a percentage of the acetyl groups present in the molecule. Thus the prior art suggests an efficiency of 2/5=40% for penta acetyl glucose whilst the conditions provided by a detergent liquor in accordance with the invention enable a conversion efficiency of 3.4/5=67% for this material to be achieved.
Conversion efficiencies, both estimated and achieved, for other preferred materials are shown in the table below.
In general, although an appreciable increase in conversion efficiency can be achieved for most acetylated aldohexopyranoses and pyranosides, those having conversion efficiencies of less than about 50% are of less interest as they have to be used in amounts that are too large to be economically attractive. The materials of the present invention have estimated conversion efficiencies in excess of 50%, and preferably in excess of 60%.
Most preferred materials are penta acetyl glucose and octa acetyl lactose.
Levels of incorporation of the acetylated aldohexopyranoses in the detergent liquors of the invention lie in the range 10-1000 ppm, preferably from 150-500 ppm. In the detergent composition aspect of the invention the level of acetylated aldohexopyranoses in the composition lie in the range from 0.5 to 10%, preferably from 1% to 5% by weight of the product, more preferably from 2% to 4%.
The invention also requires that the wash liquor have a starting pH of at least 9.5. Preferably the starting or initial wash liquor pH is at least 10.0 and most preferably at least 10.2. As noted hereinbefore the wash liquor product concentration can lie within the range 0.1-1.0% by weight but for the purposes of determining the starting wash liquor pH, measurement is made of a 0.5% wt solution at 20°C and references to the wash liquor pH shall be construed accordingly. The starting or initial wash liquor pH is defined as the pH of the detergent liquor measured after all of the soluble components have dissolved and before any soiled fabrics have been added.
Achievement of a wash liquor pH above the minimum recited value is preferably secured by control of the component levels during manufacture of the detergent composition but can be achieved by direct addition of alkaline ingredients such as alkalis or alkali metal silicates, carbonates or phosphates to the wash liquor following dissolution of the detergent composition. However, the latter practice, although feasible for practice of the invention in commercial laundering operations, is not preferred for domestic laundering.
The detergent liquors of the invention and compositions for their production can contain any of the optional ingredients customarily used in fabric washing processes. As these ingredients are not essential to the practice of the invention, their usage therein is described for convenience with reference to their level in the detergent composition aspect of the invention.
Organic and inorganic salts are contained in the detergent compositions of the invention in an amount of from 30 to 83.5% by weight.
A principal optional component of the invention particularly in its granular form is at least one detergent organic or inorganic builder salt which can be any one of the water soluble or water insoluble salts conventionally used for this purpose. Suitable inorganic builder salts include orthophosphates, pyrophosphates, tripolyphosphates and the higher polymeric glassy phosphates, silicates, carbonates, and the water insoluble crystalline aluminosilicates such as hydrated Zeolite A, X or P. Organic builder salts include the aminocarboxylates such as the salts of nitrilotriacetic acid (NTA), ethylene diaminetetra acetic acid (EDTA) and diethylenetriaminepenta acetic acid (DETPA) and the methylene phosphonate analogues of these materials NTMP, EDTMP and DETPMP, as well as the salts of polycarboxylic acids such as lactic acid, glycolic acid and ether derivatives thereof as disclosed in Belgian Patents 821,368, 821,369 and 821,370; succinic acid, malonic acid, (ethylenedioxy) diacetic acid, maleic acid, diglycolic acid, tartaric acid, tartronic acid and fumaric acid; citric acid, aconitic acid, citraconic acid, carboxymethyloxysuccinic acid, lactoxysuccinic acid, and 2-oxy-1,1,3-propane tri-carboxylic acid; oxydisuccinic acid, 1,1,2,2-ethane tetracarboxylic acid, 1,1,3,3-propane tetracarboxylic acid and 1,1,2,3-propane tetracarboxylic acid; cyclo-pentane-cis, cis, cis-tetracarboxylic acid; cyclopentadienide pentacarboxylic acid, 2,3,4,5-tetrahydrofuran-cis, cis, cis-tetracarboxylic acid, 2,5-tetrahydrofuran-cis-dicarboxylic acid, 1,2,3,4,5,6-hexane-hexa- carboxylic acid, mellitic acid, pyromellitic acid and the phthalic acid derivatives disclosed in British Patent 1,425,343.
The builder salts preferably comprise from 5% to 70% by weight of the composition, preferably from 10% to 50% by weight for granular detergents, and may comprise mixtures of any of the above-mentioned.
The compositions of the present invention can be supplemented by all manner of detergent components. Soil suspending agents at 0.1% to 10% by weight e.g. methyl cellulose and its derivatives such as water-soluble salts of carboxymethyl-cellulose, carboxyhydroxymethyl cellulose and polyethylene glycols having a molecular weight of 400 to 10,000 are common components of the present invention. Anti caking agents, such as sodium sulphosuccinate or sodium benzoate, dyes, pigments, optical bleaches such as tri- and tetra-sulphonated zinc phthalo cyanine, and perfumes can be included in varying amounts as desired.
Enzymes in minor amounts are conventional ingredients of the compositions, those suitable for use including the materials discussed in U.S. patents 3,519,570 and 3,533,139 to McCarty and McCarty et al.
Anionic fluorescent brightening agents are well-known ingredients, examples of which are disodium 4,4'-bis-(2-diethanolamino-4-anilino-s-triazin-6-ylamino)stilbene-2:2'-disulphonate, disodium 4,4'-bis-(2-morpholino-4-anilino-s-triazin-6-ylamino)stilbene:2:2'-disulphonate, disodium 4',4-bis-(2,4-dianilino- s-triazin-6-ylamino)stilbene-2:2'-disulphonate, disodium 4,4'-bi-(2-anilino-4-(N-methyl N-2-hydroxy- ethylamino)-S-triazin-6-ylamino)stilbene-2,2'-disulphonate, disodium 4,4'-bis-(4-phenyl-2,1,3-triazol-2-yl)-stilbene-2,2'-disulphonate, disodium 4,4'-bis-(2-anilino-4-(1-methyl-2-hydroxyethylamino)-S-triazin-6-yl- amino)stilbene-2,2'-disulphonate and sodium 2-stilbyl-4"-(naphtho-1',2':4,5)-1,2,3-triazole-2"-sulphonate.
An alkali metal, or alkaline earth metal, silicate can also be present. The alkali metal silicate preferably is used in an amount from 0.5% to 10% more preferably from 3% to 8%. Suitable silicate solids have a molar ratio of Si0₂/alkali metal₂0 in the range from 0.5 to 4.0, but much more preferably from 1.0 to 1.8, especially about 1.6. The alkali metal silicates suitable herein can be commercial preparations of the combination of silicon dioxide and alkali metal oxide, fused together in varying proportions.
The present compositions also preferably contain suds regulating components in an amount of from 0.05% to 3%. Preferred are microcrystalline waxes having a melting point in the range from 35°C-115°C and saponification value of less than 100. The microcrystalline waxes are substantially water-insoluble, but are water-dispersible in the presence of organic surfactants. Preferred microcrystalline waxes having a melting point from 65°C to 100°C, a molecular weight in the range from 400-1000; and a penetration value of at least 6, measured at 77°C by ASTM-D1321. Suitable examples of the above waxes include microcrystalline and oxidized micro-crystalline petrolatum waxes; Fischer-Tropsch and oxidized Fischer-Tropsch waxes; ozokerite; ceresin; montan wax; beeswax, candelilla; and carnauba wax.
U.S. Patent 3,933,672 issued January 20 1976, to Bartollota et al. discloses silicone suds controlling agents suitable herein. The silicone material can be represented by alkylated polysiloxane materials such as silica aerogels and xerogels and hydrophobic silicas of various types. The silicone material can be described as siloxane having the formula:
wherein x is from 20 to 2,000 and R and R' are each alkyl or aryl groups, especially methyl, ethyl, propyl, butyl and phenyl. The polydimethylsiloxanes (R and R' are methyl) having a molecular weight within the range of from 200 to 2,000,000, and higher, are all useful as suds controlling agents. Additional suitable silicone materials wherein the side chain groups R and R' are alkyl, aryl, or mixed alkyl or aryl hydrocarbyl groups exhibit useful suds controlling properties. Examples of the like ingredients include diethyl-, dipropyl-, dibutyl-, methyl-, ethyl-, phenyl-, methylpolysiloxanes and the like. Additional useful silicone suds controlling agents can be represented by a mixture of an alkylated siloxane, as referred to hereinbefore, and solid silica. Such mixtures are prepared by affixing the silicone to the surface of the solid silica. A preferred silicone suds controlling agent is represented by a hydrophobic silanated (most preferably trimethylsilanated) silica having a particle size in the range from 10 nm to 20 nm and a specific surface area above 50 m²/g, intimately admixed with dimethyl silicone fluid having a molecular weight in the range from 500 to 200,000 at a weight ratio of silicone to silanated silica of from 1:1 to 1:10. The silicone suds suppressing agent is advantageously releasably incorporated in a water-soluble or water-dispersible, substantially non-surface-active detergent-impermeable carrier.
Particularly useful suds suppressors are the self-emulsifying silicone suds suppressors, described in DE-A-2,646,126 published April 28, 1977. An example of such a compound is DB-544, commercially available from Dow Corning, which is a siloxane/glycol copolymer.
Where not included as a component of the builder system, a highly preferred ingredient of the detergent liquors and of compositions for their production, is a polyphosphonic acid or salt thereof in an amount from 0.01 to 4%, especially from 0.1 to 1.0% by weight. At this level of incorporation, which is below the range of levels normally employed for detergent builders, the polyphosphonic acid or salt thereof is found to provide bleachable stain detergency benefits.
Especially preferred polyphosphonates have the formula:-
wherein each R is CH₂P0₃H₂ or a water-soluble salt thereof and n is from 0 to 2. Examples of compounds within this class are aminotri-(methylenephosphonic acid), ethylene diamine tetra(methylenephosphonic acid) and diethylene triamine penta(methylene phosphonic acid). Of these, ethylenediamine tetra-(methylene phosphonic acid) is particularly preferred.
The detergent composition preferably contains a water-soluble copolymeric carboxylic acid or salt thereof in an amount of from 0.1% to 5% by weight of the composition as a soil antiredeposition agent. The copolymeric polycarboxylic acid, which comprises at least two carboxyl radicals separated from each other by not more than two carbon atoms and which has an average molecular weight in the range from 500 to 2,000,000, more preferably from 12,000 to 1,500,000 comprises:

(a) polycarboxylic acid units having the general formula
wherein X, Y, and Z are each selected from the group consisting of hydrogen, methyl, aryl, alkaryl, carboxyl, hydroxy and carboxymethyl; at least one of X, Y, and Z being selected from the group consisting of carboxyl and carboxymethyl, provided that X and Y can be carboxymethyl only when Z is selected from carboxyl and carboxymethyl and wherein only one of X, Y, and Z can be methyl, aryl, hydroxyl and alkaryl, and
(b) monomer units selected from
wherein R, is a C, to C₁₂ alkyl group or a C, to C,₂ acyl group, R, optionally being hydroxy substituted,
wherein R₂ is H or CH₃ and R₃ is H, or a C, to C_io alkyl group, R_z, R₃ optionally being hydroxy substituted,
wherein each of R₄ to R₇ is H or an alkyl groups such that R₄ to R₇ together have from 1 to 20 carbon atoms, R₄-_R each optionally being hydroxy substituted, and
in which R₈ is benzyl or pyrrolidone.

Highly preferred examples of such carboxylates are 1:1 styrene/maleic acid copolymer, di-isobutylene/ maleic acid copolymers, methyl vinyl ether/maleic acid copolymers and maleic acid/acrylic acid copolymers having a molar ratio between 1:1 and 1:4. Other suitable polycarboxylates are poly-alpha- hydroxy acrylates and lactones thereof as described in Belgian Patent 817,678 and B.P. 1,425,307.
Another suitable component of detergent compositions in accordance with the invention is a water-soluble magnesium salt which is added at levels in the range from 0.015% to 0.2%, preferably from 0.03% to 0.15% and more preferably from 0.05% to 0.12% by weight of the compositions (based on weight of magnesium). Suitable magnesium salts include magnesium sulphate, magnesium sulphate heptahydrate, magnesium chloride, magnesium chloride hexahydrate, magnesium fluoride and magnesium acetate.
In the broadest aspect of the invention, the various components can be added independently and directly to the water to form the wash liquor, the only requirement being that the acetylated aldohexopyranose or -pyranoside should not be added before the inorganic peroxy bleach. Simultaneous addition of all of the ingredients is a convenient method of operation, and a preferred mode comprises the use of a preformed detergent composition to form the detergent liquor.
In this preferred mode the surfactant typically together with builder and filler salts is formed into an aqueous slurry and converted into a granule, preferably by spray drying. For a typical spray drying process, the aqueous slurry is mixed at a temperature in the range 70-90°C and the water-content of the slurry adjusted to a range of 25% to 45%, preferably 30%-38% by weight. Spray drying is undertaken with drying gas inlet temperature of from 250-350°C, preferably 275-330°C, providing a final moisture content in the range of from 8% to 14% by weight. Nonionic surfactant, where present, can then be sprayed in fluid form onto the spray dried detergent granules.
The inorganic peroxy bleach and the acetylated aldohexopyranose or -pyranoside are then dry-mixed independently with the spray dried granules to form the detergent composition. A preferred form of the acetylated aldohexopyranose or -pyranoside for incorporation into a detergent composition is as an extrudate formed by the process described in European Patent Application Publication No. 0062523 filed October 23, 1981 (pub. 13.10.82).
In this process the acetylated aldohexopyranose or -pyranoside is first formed into a particulate having a particle size distribution such that at least 50%, preferably at least 80% passes a 250 pm screen. in preferred embodiments of the invention at least 50% and most preferably at least 80% of the acetylated compounds pass through a 100 pm screen. This particulate material is then mixed with an ethoxylated nonionic surfactant melting in the range from 20°C to 60°C to give a homogeneous friable mass comprising from 75% to 95%, preferably from 84% to 90% of solid and from 5% to 25%, preferably from 10% to 16% of ethoxylated alcohol. This is then mechanically extruded through an extruder having a radial discharge through an apertured screen to form elongate particles having an average lateral dimension in the range from 0.5 mm to 2 mm and an average longitudinal dimension of from 1 mm to 6 mm.
Suitable nonionic surfactants are primary or secondary C₉-C₁₈ alcohols haying an average degree of ethoxylation of from 3 to 30, more preferably 5 to 14, an example being tallow alcohol condensed with an average of 11 ethylene oxide groups per mole of alcohol.
In such executions, the incorporation into the extrusion mixture of a low level of an acidic material, prevents or minimises the discolouration of the extrudates when they are subsequently incorporated into, and stored in contact with, alkaline detergent compositions. This discolouration arises as a result of alkali attack on aldehyde-sugars which leads to the formation of complex coloured compounds.
Certain of the preferred acetylated aldohexopyranosides such as alpha-methyl tetraacetyl glucose do not suffer this discolouration as they lack the hemiacetyl linkages which are prone to alkaline attack. Surprisingly, however, octaacetyl lactose which does contain such a linkage does not display discolouration when incorporated into an extrudate with a nonionic as described above and subjected to storage. Accordingly, the tetra acetyl C_l-C₁₂ alkyl glucosides and octa acetyl lactose are the preferred ester type peroxy bleach precursors for incorporation into particulate alkaline detergent compositions.
The detergent composition aspect of the invention can take a variety of particulate forms other than spray dried granules such as agglomerates made in rotary drums, pans or fluidised beds, noodles or ribbons made by extrusion techniques, as well as compressed particulate forms such as tablets or pellets. In all of these forms the acetylated aldohexopyranose or -pyranoside can be processed with the other components provided that, as discussed above, it is not formed into intimate mixtures with those components which are alkaline in nature, or processed under hot aqueous alkaline conditions, which promote hydrolysis of the acyl groups and thus reduce the potential for peroxy acid production.
Typical detergent compositions contain 5-15% of the surfactant system, 15-25% of an inorganic perhydrate such as sodium perborate or percarbonate, 1-5% of acetylated aldohexopyranose or -pyranoside and 55-69% of organic or inorganic salts, miscellaneous additives and water. A preferred surfactant system is a water soluble anionic-cationic-nonionic mixture in which the anionic is present in an amount greater than the stoichiometric equivalent of the cationic surfactant and the ratio of anionic:nonionic surfactants is >1:1 by weight.
The invention also embraces the use of additive products together with conventional laundry detergents to form the detergent liquors. The additive products may be in either liquid or solid form, and if solid may be particulate or non-particulate in nature. A particularly preferred non-particulate additive product is disclosed in British Patent Specification No. 1,586,769 and European Application No. 78200051.7 Publication No. 0000226.
Briefly, these disclosures relate to additive products comprising organic peroxy acid bleach precursor in water-releasable combination with a non-particulate flexible substrate, preferably in sheet form, in which the precursor to substrate ratio lies in the range from 1:10 to 30:1, more preferably from 1:2 to 8:1.
European Application No. 78200051.7 discloses the combination of this precursor-substrate system with a nonionic-cationic surfactant mixture in which the ratio of nonionic to cationic lies in the range from 20:1 to 1:2, preferably from 5:1 to 3:2.
The additive products of BP 1,586,769 and European Application No. 0000226 are neutral to acidic in character so that the discolouration problems associated with the incorporation of the precursors of the invention into particulate detergent compositions do not arise.
Suitable particulate additive products are disclosed in European Patent Application No. 79200303.0 Publication No. 0006655 and the previously mentioned European Patent Application Publication No. 0062523, both of which relate to the use of normally solid, water soluble or water dispersible organic materials as a component of the additive product. Preferred materials are solid at temperatures below 25°C and more preferably do not soften appreciably below 30°C, such as ethoxylated alcohols having an alkyl chain length greater than 16 carbon atoms and containing at least eleven moles of ethylene oxide per mole of alcohol.
The invention is illustrated in the following non limitative examples in which all parts and percentages are by weight unless otherwise specified.

Example 1

A laundry liquor was made up by adding the following ingredients simultaneously to the drum of a Miele Automatic washing machine containing 12 litres water of 10°H (Calcium/Magnesium ratio 5:1) and temperature 18°C.

7.14 g Sodium C₁₁._S alkyl linear alkyl benzene sulphonate
33.5 g Sodium perborate tetrahydrate
5.7 g Penta acetyl glucose (PAG)
0.5 g Sodium ethylene diamine tetramethylene phosphonate (Molar ratio of H₂0₂ (sodium perborate) to PAG 15:1)

The pH was adjusted to 9.5 with 12 g citric acid and the machine was started using a 40°C low agitation cycle. 25 ml samples of wash liquor were extracted at 2 minute intervals and analysed for peracetic acid using the following technique.
The 25 ml samples of wash liquor were added to a solution containing 6 mls glacial acetic acid and 10 mls KI solution (10%). The solution was maintained at 0°C by the copious addition of crushed ice. The iodine produced (through peracetic acid oxidation of n was then titrated with standard sodium thiosulphate (0.01 M) solution, until the end point was reached.
After 12 minutes the maximum level of peracetic acid release was recorded corresponding to 2.5 moles of peracetic acid per mole of PAG (conversion efficiency 50%). The experiment was repeated using the H₂0₂ /PAG molar ratios and pH levels shown below.
It can be seen that, in order to obtain a release of at least 2.5 moles of peracetic acid per mole of penta acetyl glucose, a starting pH of at least 9.5 is necessary and that, with increasing pH, the perhydrolysis of the acetyl group is increasingly favoured relative to hydrolysis.

Example 2

The procedure of Example 1 was repeated using
14.28 g Sodium C_11.8 alkyl linear alkyl benzene sulphonate
67.0 g Sodium perborate tetrahydrate
5.7 g Penta acetyl glucose (PAG)
0.5 g Sodium ethylene diamine tetramethylene phosphonate to give a molar ratio of H₂0₂ to PAG of 30:1 and the pH was adjusted to 11.5 with 8.5 g sodium hydroxide. 25 ml samples of wash liquor were extracted at 2 minute intervals and analysed for peracetic acid and after 8 minutes the maximum level of peracetic acid release corresponded to 3.6 moles of peracetic acid per mole of PAG (conversion efficiency 72%). The experiment was repeated using Hz02/PAG molar ratios and pH levels shown below.

This example illustrates the benefit of increased perhydrate:polyol acetate ratio on the yield of peracetic acid per mole of penta acetyl glucose.

Example 3

The procedure of Example 1 was repeated using 135 g of commercially available granular detergent containing

8.5% Sodium C₁₂ alkyl benzene sulphonate
3.2% Ethoxylated alcohol surfactant
26% Sodium perborate
41% Inorganic builder salts
21.3% Miscellaneous & water
together with 5.7 g penta acetyl glucose incorporated in a formulation comprising
impregnated on a 33 cmx22.5 cm nonwoven rayon sheet.

The molar ratio of H₂0₂ to PAG was 15:1. The pH was =10 and the machine was started using a 40°C low agitation cycle. 25 ml samples of wash liquor were extracted at 2 minute intervals and analysed for peracetic acid. After 14 minutes the maximum level of peracetic acid release was recorded corresponding to 2.8 moles of peracetic acid per mole of PAG (conversion efficiency 56%).

Example 4

A detergent formulation was spray dried to provide the following composition in parts by weight.
To this base powder was added separately 21.5 parts of sodium perborate tetrahydrate, 2.6 parts of a proteolytic enzyme prill containing 0.60 parts of Alcalase (RTM) and 2.0 parts sodium tripolyphosphate, 0.4 parts of a suds suppressing prill comprising a mixture of mineral oil, wax and silica, 2.6 parts of a prill comprising 2.0 parts of penta acetyl glucose and 0.6 parts of TAE₁₁ and 0.1 parts of perfume spray on. The PAG-TAEI, prill was made by the process of British Patent Application No. 8111080 which forms a priority document made available to the public with European Patent Application No. 82301775.1 Publication No. 62523 published 13.10.82. The prills comprised cylindrical particles of length 2-3 times their diameter having a particle size >0.85 mm and less than 1.6 mm. The molar ratio of perhydrate to PAG in the composition was thus 27.4:1.
On dissolution to form a 0.5% solution at 25°C the pH was 10.2 and after 8 minutes at 60°C a release of 3.4 moles of peracetic acid per mole of PAG was obtained, an actual conversion efficiency of 64%.
Storage of the detergent product containing the PAG-TAEI1 prill under ambient conditions of temperature (15°C) and humidity (20%) resulted in the prill developing a brown surface discolouration after approximately 24 hours although this did not affect its dissolution or perhydrolysis.
Addition of lauric acid or citric acid to the extrusion mixture in an amount corresponding to 10% by weight of the mix led to a delay in the onset of this discolouration and reduction in its severity.
Replacement of the penta acetyl glucose by octa acetyl lactose or tetra acetyl alpha-methyl glucoside provides satisfactory dissolution and perhydrolysis with no discolouration on storage.

Claims

1. A laundry wash liquor adapted for the removal of oxidisable stains, particularly at temperatures of less than 60°C, said liquor containing 0.1 % to 2.0% by weight of a detergent composition comprising an organic surfactant present in an amount to give from 10 to 5000 ppm in solution, an inorganic peroxygen bleach of the perhydrate type, and a peracetic acid precursor comprising an acetylated aldohexopyranose or acetylated aldohexopyranoside containing acetyl groups on at least three adjacent carbon atoms, present in an amount to give from 10 to 1000 ppm in solution, said wash liquor having a starting pH of at least 9.5, said starting pH being defined as the pH of a 0.5 wt% solution of said composition measured at 20°C after all of the soluble components have dissolved and prior to the addition of any soiled fabrics characterised in that the inorganic peroxygen bleach is present in an amount of at least 8.5 millimoles/dm3, and in that the ratio of the moles of available peroxygen in the perhydrate to the moles of acetylated aldohexopyranose or -pyranoside is ≥12:1 whereby the percentage of the acetyl groups present in the acetylated aldohexopyranose or -pyranoside that are converted to peracetic acid is greater than 50%.

2. A laundry wash liquor according to Claim 1 characterised in that the molar ratio of available peroxygen to acetylated aldohexopyranose or -pyranoside is .15:1.

3. A laundry wash liquor according to either one of Claims 1 and 2 characterised in that the starting wash liquor pH is 10.0.

4. A laundry wash liquor according to any one of Claims 1-3 wherein the inorganic perhydrate, expressed as sodium perborate tetrahydrate, is present in an amount of from 1300 to 7000 ppm.

5. A laundry wash liquor according to Claim 4 wherein the inorganic perhydrate is present in an amount of from 1300-3200 ppm.

6. A laundry wash liquor according to any one of Claims 1-5 wherein the percentage of the acetyl groups present in the acetylated aldohexopyranose or -pyranoside that are converted to peracetic acid is greater than 60%.

7. A laundry wash liquor according to any one of Claims 1-6 wherein the acetylated aldohexopyranose or -pyranoside is a fully acetylated glucopyranose or glucopyranoside.

8. A detergent composition for use in forming the laundry wash liquor of any one of Claims 1-7 which comprises by weight of the composition

from 1% to 25% of an anionic, nonionic, ampholytic, zwitterionic or cationic organic surfactant or a mixture thereof;

and from 30 to 83.5% of one or more organic or inorganic salts;

the composition having a pH, in a 0.5% aqueous solution at 20°C of at least 9.5 characterised in that it contains from 15% to 35% of an inorganic peroxygen bleach of the perhydrate type; from 0.5% to 10% of a fully acetylated aldohexopyranose or-pyranoside; and that the ratio of the moles of available peroxygen in the perhydrate to the moles of acetylated aldohexopyranose or -pyranosides is ≥12:1.

9. A detergent composition according to Claim 8 comprising

5-15% of a mixture of water soluble anionic, cationic and nonionic surfactants in which the anionic is present in a greater than stoichiometric amount relative to the cationic surfactant and the ratio of anionic:nonionic surfactants is >1:1 by weight;

15-25% of an inorganic perhydrate selected from sodium perborate and sodium percarbonate;

1-5% acetylated glucopyranose or -pyranoside; and

55-69% of one or more organic or inorganic salts.

10. A detergent composition according to either one of Claims 8 and 9 wherein the organic or inorganic salts comprise one or more builder salts.

11. A detergent composition according to any one of Claims 8-10 further including 0.1-5% by weight of a water soluble copolymeric polycarboxylic acid or salt thereof having at least two carboxyl radicals separated from each other by not more than two carbon atoms and an average molecular weight in the range from 500 to 2,000,000, said copolymer comprising

(a) polycarboxylic acid units having the general formula

wherein X, Y, and Z are each selected from the group consisting of hydrogen, methyl, aryl, alkaryl, carboxyl, hydroxy and carboxymethyl; at least one of X, Y, and Z being selected from the group consisting of carboxyl and carboxymethyl, provided that X and Y can be carboxymethyl only when Z is selected from carboxyl and carboxymethyl and wherein only one of X, Y, and Z can be methyl, aryl, hydroxyl and alkaryl, and

(b) monomer units selected from

wherein R₁ is a C, to C₁₂ alkyl group or a C, to C₁₂ acyl group, R₁ optionally being hydroxy substituted,

wherein R₂ is H or CH₃ and R₃ is H, or a C, to C,_o alkyl group, R₂, R₃ optionally being hydroxy substituted,

wherein each of R₄ to R₇ is H or an alkyl groups such that R₄ to R₇ together have from 1 to 20 carbon atoms, R₄-R₇ each optionally being hydroxy substituted, and

in which R₈ is benzyl or pyrrolidone.

12. A method of forming a wash liquor in accordance with any one of Claims 1-7 characterised in that it comprises

a) forming a 0.1 %-2% by weight aqueous solution or dispersion of a base composition containing an organic surfactant, an inorganic peroxybleach of the perhydrate type and one or more organic or inorganic salts such that the pH of the aqueous solution or dispersion (containing 0.5 by weight of said composition measured at 20°C after all of the soluble components have dissolved and prior to the addition of any soiled fabrics) is of ≥9.5 and that the aqueous solution or dispersion contains 10 to 5000 ppm of the surfactant and at least 8.5 millimoles/dm³ of the perhydrate; and

b) adding thereto an additive composition comprising the acetylated aldohexopyranose or-pyranoside and a carrier therefor in an amount to give from 10 to 1000 ppm in solution and a molar ratio of available peroxygen in the perhydrate to the acetylated aldohexopyranose or -pyranoside of ≥12:1.

13. A method according to Claim 12 wherein the additive composition is particulate and comprises an agglomerate formed of the acetylated aldohexopyranose or -pyranoside and a water-soluble or water-dispersible organic material which is solid at temperatures below 25°C.

14. A method according to Claim 13 wherein the organic solid is an ethoxylated alcohol.

15. A method according to Claim 12 wherein the additive composition is non particulate and comprises the acetylated aldohexopyranose or -pyranoside in water releasable combination with a flexible sheet substrate.

16. A method according to Claim 15 wherein the additive composition also includes 0.1-5% by weight of a water-soluble copolymeric polycarboxylic acid or salt thereof having at least two carboxyl radicals separated from each other by not more than two carbon atoms and an average molecular weight in the range from 500 to 2,000,000, said copolymer comprising

(a) polycarboxylic acid units having the general formula

(b) monomer units selected from

wherein R₁ is a C, to C,₂ alkyl group or a C, to C₁₂ acyl group, R₁ optionally being hydroxy substituted,

wherein R₂ is H or CH₃ and R₃ is H, or a C, to C₁₀ alkyl group, R₂, R₃ optionally being hydroxy substituted,

in which R₈ is benzyl or pyrrolidone.