WO1997028908A1 - Autodishwashing method using cellulose ether as a soil release agent - Google Patents

Abstract

There is provided the use of cellulose ether material as agents enabling the improved removal of soils from tableware in automatic dish washing methods.

Description

AUTODISHWASHING METHOD USING CELLULOSE ETHER AS A SOIL RELEASE AGENT.

Technical Field

The present invention relates to the use of cellulose ether materials as agents enabling the improved release of soils from tableware in automatic dish washing methods.

Background to the Invention

A consistent effort is made by detergent manufacturers to provide detergent compositions which have the ability to clean and/or rinse even the hardest to remove soils, for example tea, coloured vegetable soils and starch-based soils, from tableware. Effort invested in finding a solution to this problem is reflected by the large number of patent applications filed in this area.

Soil release agents have traditionally been described in laundry applications where the soil release agent adheres to the surface of fabrics by way of hydrophobic interactions between the fabric and the soil release agent.

The most commonly used soil release agents incorporated into detergent compositions have been derivatives of Terephthalate and more recently polysaccharide ethers. US 4 795 584 and EP 253 567 disclose soil release polymers comprising ethyleneoxy terephthalate and polyethyleneoxy terephthalate monomer units. Polysaccharide ethers, such as cellulose ethers, have been described for example in GB 1 534 641, which discloses nonionic surfactant detergent compositions comprising cellulose ether soil release agents as alkyl and hydroxyalkyl cellulose ethers.

The Procter & Gamble pending UK patent application number 9424291.4 (attorney docket number CM 850F) discloses the use of terephthalate and cellulose ethers as soil release agents in laundry detergent compositions, providing increased soil removal performance. Japanese patent N° 5,078,698 describes an automatic dishwashing detergent composition containing a sodium or potassium salt of carboxy methyl cellulose, showing bactericide activity.

The problem underlying the present invention is the provision of a dishwashing detergent component that provides improved soil removal from tableware.

It is the surprising finding of this invention that cellulose ether soil release agents applied in a dishwashing method can enable the improved release of soils from said tableware.

The soil release agent unexpectedly adheres to the surface of the tableware, forming a barrier layer on which soils deposit. The soil release agent and attached soil are released in the subsequent wash cycle.

Cellulose ether materials are known as soil release agents as described above. Cellulose ether materials are also known in dishwashing. However, the use of cellulose ether materials as soil release agents in dishwashing has not been previously documented. Neither the problem underlying the present invention nor the subsequent solution, as indicated above, have been addressed in the prior art.

In addition, a further advantage of the present invention is the non-toxic nature of the cellulose ether soil release agents. The soil release agent, being a component of a dishwashing formulation, adheres and remains on the surface of the tableware. It is therefore preferable that the soil release agent be edible and harmless to humans when consumed. The soil release agent is preferably invisible to the naked eye, to minimise unnecessary consumer concern.

Summary of the invention

The present invention provides the use of a cellulose ether material as an agent enabling the improved release of soils from tableware when employed in a method comprising the steps of

(i) applying a coating of said cellulose ether to said tableware; (ii) 'in use¹ soiling of the coated tableware; and

(iii) washing of the tableware, thereby removing said coating and soils.

Detailed Description of the Invention

Agent enabling the improved removal of soils

According to the present invention a cellulose ether material is used as an agent enabling the improved release of soils from tableware.

The cellulose ether soil release agent is believed to adhere to the surface of the tableware providing a protective layer coating the surface of the tableware. The protective coating layer acts as the outermost surface of the tableware onto which soils will be adsorbed. The cellulose ether soil release agent and attached soil are removed from the surface of the tableware, and it is believed that a new protective coating layer is deposited, during the washing step.

Cellulose Ether Material

By cellulose ether material herein, it is meant a polymeric material having cellulose ether monomer units, preferably comprising only cellulose ether monomer units.

The polysaccharide cellulose ether material is preferably selected from the group having the general formula as shown below.

R is either hydrogen, an alkyl or carboxy alkyl group n is between 100 and 10 000

The cellulose ether is more preferably methyl cellulose, where R is CH3, or carboxy methyl cellulose, where R is CH2COO^"Na⁺. Preferably the cellulose ether has a degree of substitution of between 0.0 and 3.0, preferably between 0.5 and 2.5 and a molecular weight of between 20 000 and 150 000. According to the present invention the cellulose ether material has a degree of polymerisation of more than 100, preferably between 100 and 10 000. As used herein, the term 'degree of polymerisation (dp)' is the ratio of the weight average molecular weight to average molecular unit weight, i.e. dp = MW_W/MUW. The weight average molecular weight (MW_W) is obtained by standard analytical methods as described in Polymer handbooks. A preferred method is light scattering from polymer solutions as originally defined by Debye.

For example, the average molecular unit weight (MUW) for methyl cellulose ether may be determined from the sum of the molecular weight of the unsubstituted cellulose unit and the product of the degree of polymerisation and the molecular weight of the substituent less the hydrogen mass (1).

i.e. MUW=162 + (15-1)* ds - for methyl substituents found in methyl cellulose ethers.

MUW may also be determined from the "% methoxyl content" value (mc) also used by manufactures of methyl cellulose ethers instead of the degree of substitution, such that;

MUW = 100 - [(mol.wt. of CH2/mol.wt. of OCH3)*mc]

Application Step

Cellulose ether materials are applied as a coating to the surface of the tableware. Application of the cellulose ether material can be done by pain ting-on, spraying-on, application with a cloth or other applicator. The preferred method of application is by way of soaking and/or rinsing in a detergent solution containing between 0.0001 % and 0.1 %, preferably 0.0005% and 0.005%, most preferably 0.001 % and 0.01 % by weight active cellulose ether. The detergent solution containing cellulose ether may be provided by way of a block of poorly water-soluble material impregnated with cellulose ether, which is then suspended in the interior of the dishwasher machine. Materials similar to those used in the formation of commonly known 'toilet blocks' could find utility in this execution. Alternatively, the detergent solution can be provided by dissolution of a granular or tablet form detergent composition, as is typically a step in the washing of tableware.

The cellulose ether material may alternatively be administered by way of a rinse-aid composition preferably containing cellulose ether, non-ionic surfactants and/or hydrotropes. Rinse-aid compositions are added during the rinsing cycle of the dishwashing machine separately, and in addition to the detergent composition employed in the main wash cycle(s). The rinse-aid is dispensed by way of a standard rinse-aid dispensing system at levels of between 0.5g and lOg of rinse-aid composition per rinse cycle. Rinse-aid compositions enhance rinsing of the tableware and tend to prevent spot and film formation.

'In-use' Soiling Step

The term 'in-use' soiling can be interpreted as indicating everyday use of the tableware for example as a carrier or container for foodstuffs, but may also include painting-on, spraying-on or application of a soil with a cloth or other applicator. The variety of soils may include any food soil. Particularly good removal of soils in accord with the invention can be achieved on boiled spaghetti solution, egg, cheese and highly coloured tea stains.

Washing Step

The soiled tableware, described above, is washed in a detergent solution. Any method for washing or cleaning soiled tableware can be implemented. The preferred method of washing or cleaning is a machine dishwashing method. A preferred machine dishwashing method may be performed using any machine dishwasher commonly available on the market at a temperature of between 50 and 60°C. Said preferred machine dishwashing method comprises treating soiled tableware, selected from crockery, glassware, hollowware, silverware and cutlery and mixtures thereof, with an aqueous liquid having dissolved or dispensed therein an effective amount of a machine dishwashing detergent composition. By 'an effective amount of machine dishwashing composition' it is meant from 5g to 60g of product dissolved or dispersed in a wash solution of volume from 3 to 10 litres, as are typical product dosages and wash solution volumes commonly employed in conventional machine dishwashing methods.

In a preferred aspect the wash solution contains cellulose ether material, preferably delivered as a component of the detergent composition, at a concentration of from 0.0001 % to 0.1 %, preferably 0.0005% to 0.01 %, most preferably 0.001 % to 0.005% by weight active cellulose ether. Reapplication of a cellulose ether coating to the . tableware can thus occur in the washing step, concurrently with the removal of the 'old' coating together with soils.

Detergent Compositions

Detergent compositions are employed in the washing step as described above. The cellulose ethers are preferably present as components of the detergent composition at levels of between 0.2% and 10% , preferably 0.5% and 2% by weight active cellulose ether. The detergent composition may contain various components including surfactants, bleaching agents, detergent builders, alkalinity sources, lime soap dispersants, organic polymeric compounds including polymeric dye transfer inhibiting agents, crystal growth inhibitors, heavy metal ion sequestrants, enzymes and enzyme stabilizers, corrosion inhibitors, suds suppressors, solvents, and hydrotropes.

Surfactant

A highly preferred component of the compositions used in this invention is a surfactant system comprising surfactant selected from anionic, cationic, nonionic ampholytic and zwitterionic surfactants and mixtures thereof. Automatic dishwashing machine products should be low foaming in character and thus the foaming of the surfactant system must be suppressed or more preferably be low foaming, typically nonionic in character. The surfactant system is typically present at a level of from 0.2% to 30% by weight, more preferably from 0.5% to 10% by weight, most preferably from 1 % to 5% by weight of the compositions. A typical listing of anionic, nonionic, ampholytic and zwitterionic classes, and species of these surfactants, is given in U.S. P. 3,929,678 issued to Laughlin and Heuring on December, 30, 1975. A list of suitable cationic surfactants is given in U.S. P. 4,259,217 issued to Murphy on March 31, 1981. A listing of surfactants typically included in automatic dishwashing detergent compositions is given for example, in EP- A-0414 549 and PCT Applications Nos. WO 93/08876.

Nonionic surfactant

Essentially any nonionic surfactants useful for detersive purposes can be included, in the compositions. Preferred, non-limiting classes of useful nonionic surfactants are listed below.

Nonionic ethoxylated alcohol surfactant

The alkyl ethoxylate condensation products of aliphatic alcohols with from about 1 to about 25 moles of ethylene oxide are suitable for use herein. The alkyl chain of the aliphatic alcohol can either be straight or branched, primary or secondary, and generally contains from 6 to 22 carbon atoms. Particularly preferred are the condensation products of alcohols having an alkyl group containing from 8 to 20 carbon atoms with from about 2 to about 10 moles of ethylene oxide per mole of alcohol.

Nonionic ethoxylated/propoxylated fatty alcohol surfactant

The ethoxylated Cg-Cig fatty alcohols and Cg-Cis mixed ethoxylated/propoxylated fatty alcohols are suitable surfactants for use herein, particularly where water soluble. Preferably the ethoxylated fatty alcohols are the CjQ-Cig ethoxylated fatty alcohols with a degree of ethoxylation of from 3 to 50, most preferably these are the C12-C1 g ethoxylated fatty alcohols with a degree of ethoxylation from 3 to 40. Preferably the mixed ethoxylated/propoxylated fatty alcohols have an alkyl chain length of from 10 to 18 carbon atoms, a degree of ethoxylation of from 3 to 30 and a degree of propoxylation of from 1 to 10.

Nonionic EO/PO condensates with propylene elvcol The condensation products of ethylene oxide with a hydrophobic base formed by the condensation of propylene oxide with propylene glycol are suitable for use herein. The hydrophobic portion of these compounds preferably has a molecular weight of from about 1500 to about 1800 and exhibits water insolubility. Examples of compounds of this type include certain of the commercially-available PluronicTM surfactants, marketed by BASF.

Nonionic EQ condensation products with propylene oxide/ethylene diamine adducts

The condensation products of ethylene oxide with the product resulting from the reaction of propylene oxide and ethylenediamine are suitable for use herein. The hydrophobic moiety of these products consists of the reaction product of ethylenediamine and excess propylene oxide, and generally has a molecular weight of from about 2500 to about 3000. Examples of this type of nonionic surfactant include

TM certain of the commercially available Tetronic compounds, marketed by BASF.

Oxygen-releasing bleaching system

An optional feature of the compositions of the present invention is an oxygen-releasing bleaching system. In one preferred aspect the bleaching system contains a hydrogen peroxide source and an organic peroxyacid bleach precursor compound. The production of the organic peroxyacid occurs by an in situ reaction of the precursor with a source of hydrogen peroxide. Preferred sources of hydrogen peroxide include inorganic perhydrate bleaches. In an alternative preferred aspect a preformed organic peroxyacid is incorporated directly into the composition. Compositions containing mixtures of a hydrogen peroxide source and organic peroxyacid precursor in combination with a preformed organic peroxyacid are also envisaged. Inorganic perhydrate bleaches

The compositions in accord with the invention preferably include a hydrogen peroxide source, as an oxygen-releasing bleach. Suitable hydrogen peroxide sources include the inorganic perhydrate salts.

The inorganic perhydrate salts are normally incorporated in the form of the sodium salt at a level of from 1 % to 40% by weight, more preferably from 2% to 30% by weight and most preferably from 5% to 25% by weight of the compositions.

Examples of inorganic perhydrate salts include perborate, percarbonate, perphosphate, persulfate and persilicate salts. The inorganic perhydrate salts are normally the alkali metal salts. The inorganic perhydrate salt may be included as the crystalline solid without additional protection. For certain perhydrate salts however, the preferred executions of such granular compositions utilize a coated form of the material which provides better storage stability for the perhydrate salt in the granular product.

Sodium perborate can be in the form of the monohydrate of nominal formula NaBθ2H2θ2 or the tetrahydrate NaBθ2H2θ2.3H2θ.

Alkali metal percarbonates, particularly sodium percarbonate are preferred perhydrates for inclusion in compositions in accordance with the invention. Sodium percarbonate is an addition compound having a formula corresponding to 2Na2CO3.3H2O2, and is available commercially as a crystalline solid. Sodium percarbonate, being a hydrogen peroxide addition compound tends on dissolution to release the hydrogen peroxide quite rapidly which can increase the tendency for localised high bleach concentrations to arise. The percarbonate is most preferably incorporated into such compositions in a coated form which provides in- product stability.

A suitable coating material providing in product stability comprises mixed salt of a water soluble alkali metal sulphate and carbonate. Such coatings together with coating processes have previously been described in GB- 1,466,799, granted to Interox on 9th March 1977. The weight ratio of the mixed salt coating material to percarbonate lies in the range from 1 : 200 to 1 : 4, more preferably from 1 : 99 to 1 : 9, and most preferably from 1 : 49 to 1 : 19. Preferably, the mixed salt is of sodium sulphate and sodium carbonate which has the general formula Na2SO4.n.Na2CO3 wherein n is from 0.1 to 3, preferably n is from 0.3 to 1.0 and most preferably n is from 0.2 to 0.5.

Other coatings which contain silicate (alone or with borate salts or boric acids or other inorganics), waxes, oils, fatty soaps can also be used advantageously within the present invention.

Potassium peroxymonopersulfate is another inorganic perhydrate salt of utility in the compositions herein.

Peroxyacid bleach precursor

Peroxyacid bleach precursors are compounds which react with hydrogen peroxide in a perhydrolysis reaction to produce a peroxyacid. Generally peroxyacid bleach precursors may be represented as

O

II

X-C -L

where L is a leaving group and X is essentially any functionality, such that on perhydrolysis the structure of the peroxyacid produced is

O

II

X- C -OOH

Peroxyacid bleach precursor compounds are preferably incorporated at a level of from 0.5% to 20% by weight, more preferably from 1 % to 10% by weight, most preferably from 1.5% to 5% by weight of the compositions.

Suitable peroxyacid bleach precursor compounds typically contain one or more N- or O-acyl groups, which precursors can be selected from a wide range of classes. Suitable classes include anhydrides, esters, i ides, lactams and acylated derivatives of imidazoles and oximes. Examples of useful materials within these classes are disclosed in GB-A-1586789. Suitable esters are disclosed in GB-A-836988, 864798, 1147871, 2143231 and EP-A-0170386.

Leaving groups

The leaving group, hereinafter L group, must be sufficiently reactive for the perhydrolysis reaction to occur within the optimum time frame (e.g., a wash cycle). However, if L is too reactive, this activator will be difficult to stabilize for use in a bleaching composition.

Preferred L groups are selected from the group consisting of:

O

N-C-R¹ — N Λ N — N— C-CH— R⁴ L I

R³ U R³ Y

and mixtures thereof, wherein R is an alkyl, aryl, or alkaryl group containing from 1 to 14 carbon atoms, R is an alkyl chain containing from 1 to 8 carbon atoms, R is H or R 3 , and Y is H or a solubilizing group. Any of R 1 , R3 and R 4 may be substituted by essentially any functional group including, for example alkyl, hydroxy, alkoxy, halogen, amine, nitrosyl, amide and ammonium or alkyl ammonium groups

The preferred solubilizing groups are -SO^^'M^"1" , -CO~^~M⁺, -SO M ^" , -N⁺(R³) .X^" and O< --N(R^J)₃ and most preferably -SO₃ M and -CO₂ M wherein R^J is an alkyl chain containing from 1 to 4 carbon atoms, M is a cation which provides solubility to the bleach activator and X is an anion which provides solubility to the bleach activator. Preferably, M is an alkali metal, ammonium or substituted ammonium cation, with sodium and potassium being most preferred, and X is a halide, hydroxide, methylsulfate or acetate anion.

Perbenzoic acid precursor

Perbenzoic acid precursor compounds provide perbenzoic acid on perhydrolysis.

Suitable O-acylated perbenzoic acid precursor compounds include the substituted and unsubstituted benzoyl oxybenzene sulfonates, including for example benzoyl oxybenzene sulfonate:

Also suitable are the benzoylation products of sorbitol, glucose, and all saccharides with benzoylating agents, including for example:

Ac = COCH3; Bz = Benzoyl

Perbenzoic acid precursor compounds of the imide type include N-benzoyl succinimide, tetrabenzoyl ethylene diamine and the N-benzoyl substituted ureas. Suitable imidazole type perbenzoic acid precursors include N-benzoyl imidazole and N-benzoyl benzimidazole and other useful N-acyl group-containing perbenzoic acid precursors include N-benzoyl pyrrolidone, dibenzoyl taurine and benzoyl pyroglutamic acid.

Other perbenzoic acid precursors include the benzoyl diacyl peroxides, the benzoyl tetraacyl peroxides, and the compound having the formula:

Phthalic anhydride is another suitable perbenzoic acid precursor compound herein:

Suitable N-acylated lactam perbenzoic acid precursors have the formula:

wherein n is from 0 to 8, preferably from 0 to 2, and R is a benzoyl group.

Perbenzoic acid derivative precursors

Perbenzoic acid derivative precursors provide substituted perbenzoic acids on perhydrolysis.

Suitable substituted perbenzoic acid derivative precursors include any of the herein disclosed perbenzoic precursors in which the benzoyl group is substituted by essentially any non-positively charged (i.e.; non-cationic) functional group including, for example alkyl, hydroxy, alkoxy, halogen, amine, nitrosyl and amide groups.

A preferred class of substituted perbenzoic acid precursor compounds are the amide substituted compounds of the following general formulae:

R¹ — C — N — R² C L R¹ N — C — R² C — L

II

O or R O

wherein Rl is an aryl or alkaryl group with from 1 to 14 carbon atoms, R^ is an arylene, or alkarylene group containing from 1 to 14 carbon atoms, and R^ is H or an alkyl, aryl, or alkaryl group containing 1 to 10 carbon atoms and L can be essentially any leaving group. R^ preferably contains from 6 to 12 carbon atoms. R^ preferably contains from 4 to 8 carbon atoms. R may be aryl, substituted aryl or alkylaryl containing branching, substitution, or both and may be sourced from either synthetic sources or natural sources including for example, tallow fat. Analogous structural variations are permissible for R^. The substitution can include alkyl, aryl, halogen, nitrogen, sulphur and other typical substituent groups or organic compounds. R^ is preferably H or methyl. R¹ and R^ should not contain more than 18 carbon atoms in total. Amide substituted bleach activator compounds of this type are described in EP- A-0170386. Cationic peroxyacid precursors

Cationic peroxyacid precursor compounds produce cationic peroxyacids on perhydrolysis.

Typically, cationic peroxyacid precursors are formed by substituting the peroxyacid part of a suitable peroxyacid precursor compound with a positively charged functional group, such as an ammonium or alkyl ammonium group, preferably an ethyl or methyl ammonium group. Cationic peroxyacid precursors are typically present in the compositions as a salt with a suitable anion, such as for example a halide ion or a methylsulfate ion.

The peroxyacid precursor compound to be so cationically substituted may be a perbenzoic acid, or substituted derivative thereof, precursor compound as described hereinbefore. Alternatively, the peroxyacid precursor compound may be an alkyl percarboxylic acid precursor compound or an amide substituted alkyl peroxyacid precursor as described hereinafter

Cationic peroxyacid precursors are described in U.S. Patents 4,904,406; 4,751,015; 4,988,451 ; 4,397,757; 5,269,962; 5,127,852; 5,093,022; 5,106,528; U.K. 1,382,594; EP 475,512, 458,396 and 284,292; and in JP 87-318,332.

Examples of preferred cationic peroxyacid precursors are described in UK Patent Application No. 9407944.9 (attorney's docket no. CM642F) and US Patent Application Nos. 08/298903, 08/298650, 08/298904 and 08/298906 (attorney's docket nos. 5413 to 5416).

Suitable cationic peroxyacid precursors include any of the ammonium or alkyl ammonium substituted alkyl or benzoyl oxybenzene sulfonates, N-acylated caprolactams, and monobenzoyltetraacetyl glucose benzoyl peroxides.

A preferred cationically substituted benzoyl oxybenzene sulfonate is the 4-(trimethyl ammonium) methyl derivative of benzoyl oxybenzene sulfonate:

A preferred cationically substituted alkyl oxybenzene sulfonate has the formula:

Preferred cationic peroxyacid precursors of the N-acylated caprolactam class include the trialkyl ammonium methylene benzoyl caprolactams, particularly trimethyl ammonium methylene benzoyl caprolactam:

Other preferred cationic peroxyacid precursors of the N-acylated caprolactam class include the trialkyl ammonium methylene alkyl caprolactams:

where n is from 0 to 12, particularly from 1 to 5.

Another preferred cationic peroxyacid precursor is 2-(N,N,N-trimethyl ammonium) ethyl sodium 4-sulphophenyl carbonate chloride. Alkyl percarboxylic acid bleach precursors

Alkyl percarboxylic acid bleach precursors form percarboxylic acids on perhydrolysis. Preferred precursors of this type provide peracetic acid on perhydrolysis.

Preferred alkyl percarboxylic precursor compounds of the imide type include the N- ,N,N^N^ tetra acetylated alkylene diamines wherein the alkylene group contains from 1 to 6 carbon atoms, particularly those compounds in which the alkylene group contains 1 , 2 and 6 carbon atoms. Tetraacetyl ethylene diamine (TAED) is particularly preferred.

Other preferred alkyl percarboxylic acid precursors include sodium 3,5,5-tri-methyl hexanoyloxybenzene sulfonate (iso-NOBS), sodium nonanoyloxybenzene sulfonate (NOBS), sodium acetoxybenzene sulfonate (ABS) and penta acetyl glucose.

Amide substituted alkyl peroxyacid precursors

Amide substituted alkyl peroxyacid precursor compounds are also suitable, including those of the following general formulae:

R¹ C — N — -R² -C L R¹ — N — C — R² — C — L

II L ||

O R⁵ O or O

wherein R* is an alkyl group with from 1 to 14 carbon atoms, R^ is an alkylene group containing from 1 to 14 carbon atoms, and R^ is H or an alkyl group containing 1 to 10 carbon atoms and L can be essentially any leaving group. R* preferably contains from 6 to 12 carbon atoms. R^ preferably contains from 4 to 8 carbon atoms. Rl may be straight chain or branched alkyl containing branching, substitution, or both and may be sourced from either synthetic sources or natural sources including for example, tallow fat. Analogous structural variations are permissible for R^. The substitution can include alkyl, halogen, nitrogen, sulphur and other typical substituent groups or organic compounds. R^ is preferably H or methyl. R* and R^ should not contain more than 18 carbon atoms in total. Amide substituted bleach activator compounds of this type are described in EP-A-0170386. Benzoxazin organic peroxyacid precursors

Also suitable are precursor compounds of the benzoxazin-type, as disclosed for example in EP-A-332,294 and EP-A-482,807, particularly those having the formula:

including the substituted benzoxazins of the type

wherein R, is H, alkyl, alkaryl, aryl, arylalkyl, and wherein 1^, R^, R4, and R^ may be the same or different substituents selected from H, halogen, alkyl, alkenyl, aryl, hydroxyl, alkoxyl, amino, alkyl amino, COORg (wherein Rg is H or an alkyl group) and carbonyl functions.

An especially preferred precursor of the benzoxazin-type is:

Preformed organic peroxyacid

The organic peroxyacid bleaching system may contain, in addition to, or as an alternative to, an organic peroxyacid bleach precursor compound, a preformed organic peroxyacid , typically at a level of from 0.5% to 25% by weight, more preferably from 1 % to 10% by weight of the composition.

A preferred class of organic peroxyacid compounds are the amide substituted compounds of the following general formulae:

_R1 — _c — _N — _R2 — _c — OOH R¹ — N — C — R² — C — OOH

O R⁵ 0 or R⁵ O O

wherein R^ is an alkyl, aryl or alkaryl group with from 1 to 14 carbon atoms, R^ is an alkylene, arylene, and alkarylene group containing from 1 to 14 carbon atoms, and R^ is H or an alkyl, aryl, or alkaryl group containing 1 to 10 carbon atoms. R¹ preferably contains from 6 to 12 carbon atoms. R^ preferably contains from 4 to 8 carbon atoms. R* may be straight chain or branched alkyl, substituted aryl or alkylaryl containing branching, substitution, or both and may be sourced from either synthetic sources or natural sources including for example, tallow fat. Analogous structural variations are permissible for R^. The substitution can include alkyl, aryl, halogen, nitrogen, sulphur and other typical substituent groups or organic compounds. R^ is preferably H or methyl. R and R^ should not contain more than 18 carbon atoms in total. Amide substituted organic peroxyacid compounds of this type are described in EP-A-0170386.

Other organic peroxyacids include diacyl and tetraacylperoxides, especially diperoxydodecanedioc acid, diperoxytetradecanedioc acid, and diperoxyhexadecanedioc acid. Dibenzoyl peroxide is a preferred organic peroxyacid herein. Mono- and diperazelaic acid, mono- and diperbrassylic acid, and N-phthaloylaminoperoxicaproic acid are also suitable herein.

Water-soluble bismuth compound

The compositions used in this invention may contain a water-soluble bismuth compound, preferably present at a level of from 0.005% to 20% , more preferably from 0.01 % to 5 % , most preferably from 0.1 % to 1 % by weight of the compositions.

The water-soluble bismuth compound may be essentially any salt or complex of bismuth with essentially any inorganic or organic counter anion. Preferred inorganic bismuth salts are selected from the bismuth trihalides, bismuth nitrate and bismuth phosphate. Bismuth acetate and citrate are preferred salts with an organic counter anion.

Water-soluble sulfate salt

The compositions may optionally contain a water-soluble sulfate salt, preferably present at a level of from 0.1 % to 40% , more preferably from 1 % to 30% , most preferably from 5% to 25% by weight of the compositions.

The water-soluble sulfate salt may be essentially any salt of sulfate with any counter cation. Preferred salts are selected from the sulfates of the alkali and alkaline earth metals, particularly sodium sulfate.

Additional corrosion inhibitor compound

The compositions may contain additional corrosion inhibitors preferably selected from organic silver coating agents, particularly paraffin, nitrogen-containing corrosion inhibitor compounds and Mn(II) compounds, particularly Mn(II) salts of organic ligands.

Organic silver coating agents are described in PCT Publication No. WO94/ 16047 (attorney's docket no. CM497M) and copending UK Application No. UK 9413729.6 (attorney's docket no. CM750F). Nitrogen-containing corrosion inhibitor compounds are disclosed in copending European Application no. EP 93202095.1 (attorney's docket no. CM571F). Mn(H) compounds for use in corrosion inhibition are described in copending UK Application No. 9418567.5 (attorney's docket no. CM719FM).

Organic silver coating agents

Organic silver coating agent may be incorporated at a level of from 0.05% to 10%, preferably from 0.1 % to 5% by weight of the total composition.

The functional role of the silver coating agent is to form 'in use' a protective coating layer on any silverware components of the washload to which the compositions of the invention are being applied. The silver coating agent should hence have a high affinity for attachment to solid silver surfaces, particularly when present in as a component of an aqueous washing and bleaching solution with which the solid silver surfaces are being treated.

Suitable organic silver coating agents herein include fatty esters of mono- or polyhydric alcohols having from 1 to about 40 carbon atoms in the hydrocarbon chain.

The fatty acid portion of the fatty ester can be obtained from mono- or poly-carboxylic acids having from 1 to about 40 carbon atoms in the hydrocarbon chain. Suitable examples of monocarboxylic fatty acids include behenic acid, stearic acid, oleic acid, palmitic acid, myristic acid, lauric acid, acetic acid, propionic acid, butyric acid, isobutyric acid, Valerie acid, lactic acid, glycolic acid and β,β'- dihydroxyisobutyric acid. Examples of suitable polycarboxylic acids include: n-butyl-malonic acid, isocitric acid, citric acid, maleic acid, malic acid and succinic acid.

The fatty alcohol radical in the fatty ester can be represented by mono- or polyhydric alcohols having from 1 to 40 carbon atoms in the hydrocarbon chain. Examples of suitable fatty alcohols include; behenyl, arachidyl, cocoyl, oleyl and lauryl alcohol, ethylene glycol, glycerol, ethanol, isopropanol, vinyl alcohol, diglycerol, xylitol, sucrose, erythritol, pentaerythritol, sorbitol or sorbitan.

Preferably, the fatty acid and/or fatty alcohol group of the fatty ester adjunct material have from 1 to 24 carbon atoms in the alkyl chain.

Preferred fatty esters herein are ethylene glycol, glycerol and sorbitan esters wherein the fatty acid portion of the ester normally comprises a species selected from behenic acid, stearic acid, oleic acid, palmitic acid or myristic acid.

The glycerol esters are also highly preferred. These are the mono-, di- or tri-esters of glycerol and the fatty acids as defined above.

Specific examples of fatty alcohol esters for use herein include: stearyl acetate, palmityl di-lactate, cocoyl isobutyrate, oleyl maleate, oleyl di maleate , and tallowy 1 proprionate. Fatty acid esters useful herein include: xylitol monopalmitate, pentaerythritol monostearate, sucrose monostearate, glycerol monostearate, ethylene glycol monostearate, sorbitan esters. Suitable sorbitan esters include sorbitan monostearate, sorbitan palmitate, sorbitan monolaurate, sorbitan monomyristate, sorbitan monobehenate, sorbitan mono-oleate, sorbitan dilaurate, sorbitan distearate, sorbitan dibehenate, sorbitan dioleate, and also mixed tallowalkyl sorbitan mono- and di-esters.

Glycerol monostearate, glycerol mono-oleate, glycerol monopalmitate, glycerol monobehenate, and glycerol distearate are preferred glycerol esters herein.

Suitable organic silver coating agents include triglycerides, mono or diglycerides, and wholly or partially hydrogenated derivatives thereof, and any mixtures thereof. Suitable sources of fatty acid esters include vegetable and fish oils and animal fats. Suitable vegetable oils include soy bean oil, cotton seed oil, castor oil, olive oil, peanut oil, safflower oil, sunflower oil, rapeseed oil, grapeseed oil, palm oil and corn oil.

Waxes, including microcrystalline waxes are suitable organic silver coating agents herein. Preferred waxes have a melting point in the range from about 35 °C to about 110°C and comprise generally from 12 to 70 carbon atoms. Preferred are petroleum waxes of the paraffin and microcrystalline type which are composed of long-chain saturated hydrocarbon compounds.

Alginates and gelatin are suitable organic silver coating agents herein.

Dialkyl amine oxides such as C12-C20 methylamine oxide, and dialkyl quaternary ammonium compounds and salts, such as the C12-C20 methylammonium halides are also suitable.

Other suitable organic silver coating agents include certain polymeric materials. Poiyvinylpyrrolidones with an average molecular weight of from 12,000 to 700,000, polyethylene glycols (PEG) with an average molecular weight of from 600 to 10,000, polyamine N-oxide polymers, copolymers of N-vinylpyrrolidone and N-vinylimidazole, and cellulose derivatives such as methylceUulose, carboxymethylcellulose and hydroxyethylcellulose are examples of such polymeric materials.

Certain perfume materials, particularly those demonstrating a high substantivity for metallic surfaces, are also useful as the organic silver coating agents herein. Water-soluble builder compound

The compositions of the present invention may contain as a highly preferred component a water-soluble builder compound, typically present at a level of from 1 % to 80% by weight, preferably from 10% to 70% by weight, most preferably from 20% to 60% by weight of the composition.

Suitable water-soluble builder compounds include the water soluble monomeric polycarboxylates, or their acid forms, homo or copolymeric polycarboxylic acids. or their salts in which the polycarboxylic acid comprises at least two carboxylic radicals separated from each other by not more that two carbon atoms, carbonates, bicarbonates, borates, phosphates, and mixtures of any of the foregoing.

The carboxylate or polycarboxylate builder can be monomeric or oligomeric in type although monomeric polycarboxylates are generally preferred for reasons of cost and performance.

Suitable carboxylates containing one carboxy group include the water soluble salts of lactic acid, glycolic acid and ether derivatives thereof. Polycarboxylates containing two carboxy groups include the water-soluble salts of succinic acid, malonic acid, (ethylenedioxy) diacetic acid, maleic acid, diglycolic acid, tartaric acid, tartronic acid and fumaric acid, as well as the ether carboxylates and the sulfinyl carboxylates. Polycarboxylates containing three carboxy groups include, in particular, water-soluble citrates, aconitrates and citraconates as well as succinate derivatives such as the carboxymethyloxysuccinates described in British Patent No. 1,379,241, lactoxysuccinates described in British Patent No. 1,389,732, and aminosuccinates described in Netherlands Application 7205873, and the oxypolycarboxylate materials such as 2-oxa-l , l,3-propane tricarboxylates described in British Patent No. 1,387,447.

Polycarboxylates containing four carboxy groups include oxydisuccinates disclosed in British Patent No. 1 ,261 ,829, 1, 1,2,2-ethane tetracarboxylates, 1, 1 ,3,3-propane tetracarboxylates and 1 , 1 ,2,3-propane tetracarboxylates. Polycarboxylates containing sulfo substituents include the sulfosuccinate derivatives disclosed in British Patent Nos. 1 ,398,421 and 1,398,422 and in U.S. Patent No. 3,936,448, and the sulfonated pyrolysed citrates described in British Patent No. 1 ,439,000.

Alicyclic and heterocyclic polycarboxylates include cyclopentane-cis,cis,cis- tetracarboxylates, cyclopentadienide pentacarboxylates, 2, 3, 4, 5 -tetrahydrofuran - cis, cis, cis-tetracarboxylates, 2,5-tetrahydrofuran - cis - dicarboxylates, 2,2,5,5- tetrahydrofuran - tetracarboxylates, 1,2, 3,4,5, 6-hexane - hexacarboxylates and carboxymethyl derivatives of polyhydric alcohols such as sorbitol, mannitol and xylitol. Aromatic polycarboxylates include mellitic acid, pyromellitic acid and the phthalic acid derivatives disclosed in British Patent No. 1 ,425,343.

Of the above, the preferred polycarboxylates are hydroxycarboxylates containing up to three carboxy groups per molecule, more particularly citrates.

The parent acids of the monomeric or oligomeric polycarboxylate chelating agents or mixtures thereof with their salts, e.g. citric acid or citrate/citric acid mixtures are also contemplated as useful builder components.

Borate builders, as well as builders containing borate-forming materials that can produce borate under detergent storage or wash conditions can also be used but are not preferred at wash conditions less that about 50°C, especially less than about 40°C.

Examples of carbonate builders are the alkaline earth and alkali metal carbonates, including sodium carbonate and sesqui-carbonate and mixtures thereof with ultra-fine calcium carbonate as disclosed in German Patent Application No. 2,321 ,001 published on November 15, 1973.

Specific examples of water-soluble phosphate builders are the alkali metal tripolyphosphates, sodium, potassium and ammonium pyrophosphate, sodium and potassium and ammonium pyrophosphate, sodium and potassium orthophosphate, sodium polymeta/phosphate in which the degree of polymerization ranges from about 6 to 21, and salts of phytic acid. Partially soluble or insoluble builder compound

The compositions of the present invention may less preferably contain a partially soluble or insoluble builder compound. Examples of partially water soluble builders include the crystalline layered silicates as disclosed for example, in EP-A-0164514, DE-A-3417649 and DE-A-3742043. Examples of largely water insoluble builders include the sodium aluminosilicates, including Zeolite A, Zeolite B, Zeolite P, Zeolite X, Zeolite MAP, Zeolite HS and mixtures thereof.

Alkalinity system

The compositions preferably contain an alkalinity system containing sodium silicate having an Siθ2 : Na2θ ratio of from 1.8 to 3.0, preferably from 1.8 to 2.4, most preferably 2.0, present preferably at a level of less than 20% , preferably from 1 % to 15%, most preferably from 3% to 12% by weight of Siθ2- The alkali metal silicate may be in the form of either the anhydrous salt or a hydrated salt.

The alkalinity system also preferably contains sodium metasilicate, present at a level of at least 0.4% Siθ2 by weight. Sodium metasilicate has a nominal Siθ2 : Na2θ ratio of 1.0. The weight ratio of said sodium silicate to said sodium metasilicate, measured as Siθ2, is preferably from 50: 1 to 5:4, more preferably from 15: 1 to 2: 1 , most preferably from 10:1 to 5:2.

Heavy metal ion sequestrant

The detergent compositions preferably contain as an optional component a heavy metal ion sequestrant. By heavy metal ion sequestrant it is meant herein components which act to sequester (chelate) heavy metal ions. These components may also have calcium and magnesium chelation capacity, but preferentially they show selectivity to binding heavy metal ions such as iron, manganese and copper.

Heavy metal ion sequestrants are generally present at a level of from 0.005% to 20% , preferably from 0.1 % to 10%, more preferably from 0.25% to 7.5 % and most preferably from 0.5% to 5% by weight of the compositions. Heavy metal ion sequestrants, which are acidic in nature, having for example phosphonic acid or carboxylic acid functionalities, may be present either in their acid form or as a complex/salt with a suitable counter cation such as an alkali or alkaline metal ion, ammonium, or substituted ammonium ion, or any mixtures thereof. Preferably any salts/complexes are water soluble. The molar ratio of said counter cation to the heavy metal ion sequestrant is preferably at least 1: 1.

Suitable heavy metal ion sequestrants for use herein include organic phosphonates, such as the amino alkylene poly (alkylene phosphonates), alkali metal ethane 1 -hydroxy disphosphonates and nitrilo trimethylene phosphonates. Preferred among the above species are diethylene triamine penta (methylene phosphonate), ethylene diamine tri (methylene phosphonate) hexamethylene diamine tetra (methylene phosphonate) and hydroxy-ethylene 1, 1 diphosphonate.

Other suitable heavy metal ion sequestrant for use herein include nitrilotriacetic acid and polyaminocarboxylic acids such as ethylenediaminotetracetic acid, ethylenetriamine pentacetic acid, ethylenediamine disuccinic acid, ethylenediamine diglutaric acid, 2- hydroxypropylenediamine disuccinic acid or any salts thereof.

Especially preferred is ethylenediamine-N,N' -disuccinic acid (EDDS) or the alkali metal, alkaline earth metal, ammonium, or substituted ammonium salts thereof, or mixtures thereof. Preferred EDDS compounds are the free acid form and the sodium or magnesium salt or complex thereof.

Crystal growth inhibitor component

The detergent compositions preferably contain a crystal growth inhibitor component, preferably an organodiphosphonic acid component, incorporated preferably at a level of from 0.01 % to 5%, more preferably from 0.1 % to 2% by weight of the compositions.

By organo diphosphonic acid it is meant herein an organo diphosphonic acid which does not contain nitrogen as part of its chemical structure. This definition therefore excludes the organo aminophosphonates, which however may be included in compositions of the invention as heavy metal ion sequestrant components. The organo diphosphonic acid is preferably a -C4 diphosphonic acid, more preferably a C2 diphosphonic acid, such as ethylene diphosphonic acid, or most preferably ethane 1 -hydroxy- 1 , 1 -diphosphonic acid (HEDP) and may be present in partially or fully ionized form, particularly as a salt or complex.

Enzyme

Another optional ingredient useful in the compositions is one or more enzymes. Preferred enzymatic materials include the commercially available Upases, amylases, neutral and alkaline proteases, esterases, cellulases, pectinases, lactases and peroxidases conventionally incorporated into detergent compositions. Suitable enzymes are discussed in US Patents 3,519,570 and 3,533,139.

Preferred commercially available protease enzymes include those sold under the tradenames Alcalase, Savinase, Primase, Durazym, and Esperase by Novo Industries A/S (Denmark), those sold under the tradename Maxatase, Maxacal and Maxapem by Gist-Brocades, those sold by Genencor International, and those sold under the tradename Opticlean and Optimase by Solvay Enzymes. Protease enzyme may be incorporated into the compositions in accordance with the invention at a level of from 0.0001 % to 4% active enzyme by weight of the composition.

Preferred amylases include, for example, α-amylases obtained from a special strain of B licheniformis, described in more detail in GB- 1,269, 839 (Novo). Preferred commercially available amylases include for example, those sold under the tradename Rapidase by Gist-Brocades, and those sold under the tradename Termamyl and BAN by Novo Industries A/S. Amylase enzyme may be incorporated into the composition in accordance with the invention at a level of from 0.0001 % to 2% active enzyme by weight of the composition.

Lipolytic enzyme (lipase) may be present at levels of active lipolytic enzyme of from 0.0001 % to 2% by weight, preferably 0.001 % to 1 % by weight, most preferably from 0.001 % to 0.5% by weight of the compositions. The lipase may be fungal or bacterial in origin. Lipase from chemically or genetically modified mutants of these strains are also useful herein. A preferred lipase is described in Granted European Patent, EP-B- 0218272. An especially preferred lipase herein is obtained by cloning the gene from Humicola lanuginosa and expressing the gene in Aspergillus oryza. as host, as described in European Patent Application, EP-A-0258 068, which is commercially available from Novo Industries A/S, Bagsvaerd, Denmark, under the trade name Lipolase. This lipase is also described in U.S. Patent 4,810,414, Huge-Jensen et al, issued March 7, 1989.

Enzyme Stabilizing System

Preferred enzyme-containing compositions herein may comprise from about 0.001 % to about 10%, preferably from about 0.005% to about 8%, most preferably from about 0.01 % to about 6%, by weight of an enzyme stabilizing system. The enzyme stabilizing system can be any stabilizing system which is compatible with the detersive enzyme. Such stabilizing systems can comprise calcium ion, boric acid, propylene glycol, short chain carboxylic acid, boronic acid, chlorine bleach scavengers and mixtures thereof. Such stabilizing systems can also comprise reversible enzyme inhibitors, such as reversible protease inhibitors.

Organic polymeric compound

Organic polymeric compounds may be added as preferred components of the compositions. By organic polymeric compound it is meant essentially any polymeric organic compound commonly used as dispersants, and anti-redeposition and soil suspension agents in detergent compositions. Organic polymer compounds, however, have not been previously described as soil release agents in dishwashing. The use of organic polymeric compounds as soil release agents has not previously been described.

Organic polymeric compound is typically incorporated in the detergent compositions of the invention at a level of from 0.1 % to 30%, preferably from 0.5% to 15% , most preferably from 1 % to 10% by weight of the compositions.

Examples of organic polymeric compounds include the water soluble organic homo- or co-polymeric polycarboxylic acids or their salts in which the polycarboxylic acid comprises at least two carboxyl radicals separated from each other by not more than two carbon atoms. Polymers of the latter type are disclosed in GB-A- 1 ,596,756. Examples of such salts are polyacrylates of molecular weight 2000-10000 and their copolymers with any suitable other monomer units including modified acrylic, fumaric, maleic, itaconic, aconitic, mesaconic, citraconic and methylenemalonic acid or their salts, maleic anhydride, acrylamide, alkylene, vinylmethyl ether, styrene and any mixtures thereof. Preferred are the copolymers of acrylic acid and maleic anhydride having a molecular weight of from 20,000 to 100,000.

Preferred commercially available acrylic acid containing polymers having a molecular weight below 15,000 include those sold under the tradename Sokalan PA30, PA20, PA15, PA10 and Sokalan CP10 by BASF GmbH, and those sold under the tradename Acusol 45N by Rohm and Haas.

Preferred acrylic acid containing copolymers include those which contain as monomer units: a) from 90% to 10%, preferably from 80% to 20% by weight acrylic acid or its salts and b) from 10% to 90% , preferably from 20% to 80% by weight of a substituted acrylic monomer or its salts having the general formula -[CR2-CRι(CO-O-R3)]- wherein at least one of the substituents Ri , R2 or R3, preferably R\ or R2 is a 1 to 4 carbon alkyl or hydroxyalkyl group, Rj or R2 can be a hydrogen and R3 can be a hydrogen or alkali metal salt. Most preferred is a substituted acrylic monomer wherein Rl is methyl, R2 is hydrogen (i.e. a methacrylic acid monomer). The most preferred copolymer of this type has a molecular weight of 3500 and contains 60% to 80% by weight of acrylic acid and 40% to 20% by weight of methacrylic acid.

The polyamino compounds are useful herein including those derived from aspartic acid such as those disclosed in EP-A-305282, EP-A-305283 and EP-A-351629.

Lime soap dispersant compound

The compositions may contain a lime soap dispersant compound, preferably present at a level of from 0.1 % to 40% by weight, more preferably 1 % to 20% by weight, most preferably from 2% to 10% by weight of the compositions.

A lime soap dispersant is a material that prevents the precipitation of alkali metal, ammonium or amine salts of fatty acids by calcium or magnesium ions. Preferred lime soap dispersant compounds are disclosed in PCT Application No. WO93/08877 (attorney's docket no. CM466M).

Suds suppressing system

The compositions, when formulated for use in machine washing compositions, preferably comprise a suds suppressing system present at a level of from 0.01 % to 15%, preferably from 0.05% to 10%, most preferably from 0.1 % to 5% by weight of the composition.

Suitable suds suppressing systems for use herein may comprise essentially any known antifoam compound, including, for example silicone antifoam compounds, 2-alkyl and alcanol antifoam compounds. Preferred suds suppressing systems and antifoam compounds are disclosed in PCT Application No. WO93/08876 and copending European Application No. 93870132.3.

Polymeric dye transfer inhibiting agents

The compositions herein may also comprise from 0.01 % to 10 %, preferably from 0.05% to 0.5% by weight of polymeric dye transfer inhibiting agents.

The polymeric dye transfer inhibiting agents are preferably selected from polyamine N- oxide polymers, copolymers of N-vinylpyrrolidone and N-vinylimidazole, polyvinylpyrrolidonepolymers or combinations thereof.

pH of the compositions

The detergent compositions used in the present invention are preferably not formulated to have an unduly high pH, in preference having a pH measured as a 1 % solution in distilled water of from 8.0 to 12.0, more preferably from 9.0 to 11.8, most preferably from 9.5 to 11.5. 31

Form of the compositions

The detergent compositions can be formulated in any desirable form such as powders, granulates, pastes, liquids, gels and tablets, granular forms being preferred.

The bulk density of the granular detergent compositions in accordance with the present invention is typically of at least 650 g/litre, more usually at least 700 g/litre and more preferably from 800 g/litre to 1200 g/litre.

The particle size of the components of granular compositions in accordance with the invention should preferably be such that no more that 5 % of particles are greater than 1.4mm in diameter and not more than 5% of particles are less than 0.15mm in diameter.

Generally, if the compositions are in liquid form the liquid should be thixotropic (ie; exhibit high viscosity when subjected to low stress and lower viscosity when subjected to high stress), or at least have very high viscosity, for example, of from 1 ,000 to 10,000,000 centipoise.

Examples

The following examples illustrate the present invention.

In the compositions, the abbreviated component identifications have the following meanings:

Nonionic C13-C15 mixed ethoxylated/propoxylated fatty alcohol with an average degree of ethoxylation of 3.8 and an average degree of propoxylation of 4.5 sold under the tradename Plurafac LF404 by BASF GmbH (low foaming)

Metasilicate Sodium metasilicate (SiO2:Na2O ratio = 1.0)

Silicate Amoφhous Sodium Silicate (SiO2:Na2O ratio = 2.0)

Carbonate Anhydrous sodium carbonate

Phosphate Sodium tripolyphosphate

480N Random copolymer of 3:7 acrylic/methacrylic acid, average molecular weight about 3,500

Citrate Tri-sodium citrate dihydrate

PB1 Anhydrous sodium perborate monohydrate

CMC Carboxy Methyl Cellulose (66% active)

TAED Tetraacetyl ethylene diamine Cationic precursor Cationic peroxyacid bleach precursor salt of trialkyl ammonium methylene C5-alkyl caprolactam with tosylate

BzP Dibenzoyl peroxide

DETPMP Diethylene triamine penta (methylene phosphonic acid), marketed by Monsanto under the tradename Dequest 2060

HEDP Ethane 1 -hydroxy- 1,1 -diphosphonic acid

PMT 1 -phenyl-5-mercapto- 1 ,2 ,3 ,4-tetrazole

Bismuth nitrate Bismuth nitrate salt

Paraffin Paraffin oil sold under the tradename Winog 70 by Wintershall.

BD/MA Copolymer of butadiene/maleic acid as sold by Polysciences inc under the tradename reference no. 07787

Protease Proteolytic enzyme sold under the tradename Savinase by Novo Industries A/S (approx 2% enzyme activity).

Amylase Amylolytic enzyme sold under the tradename Termamyl 60T by Novo Industries A/S (approx 0.9% enzyme activity)

BSA Amylolytic enzyme sold under the tradename LEI 7 by Novo Industries A/S (approx 1 % enzyme activity) Sulphate Anhydrous sodium sulphate.

pH Measured as a 1 % solution in distilled water at 20°C.

In the following examples all levels of enzyme quoted are expressed as % active enzyme by weight of the composition.

The following cellulose ether-containing machine dishwashing compositions were prepared (parts by weight). Composition A is a comparative composition, compositions B to G are in accord with the invention.

Cationic - - - - 3.3 - - precursor

Paraffin 0.5 0.5 0.5 0.5 0.5 0.5 0.5

Bismuth 0.2 0.2 0.2 0.2 0.3 0.4 0.2 nitrate

BD/MA - - - - - - 0.5

PMT - - - - - - 0.5

Protease 0.04 0.04 0.04 0.04 0.04 0.06 0.04

Amylase 0.03 0.03 0.03 0.03 0.06 0.1 -

BSA - - - - - - 0.03

DETPMP 0.13 0.13 0.13 0.13 0.13 0.13 -

HEDP 1.0 1.0 1.0 1.0 1.0 1.0 -

Nonionic 2.0 2.0 2.0 2.0 2.0 2.0 1.5

Sulphate 23.0 22.8 22.4 22.7 22.2 21.5 0.3 misc inc moisture to balance pH (l % 10.7 10.7 10.7 10.7 10.7 10.7 11.0 solution)

Test method

The ability of the above detergent compositions to improve soil removal when used in accord with the method steps of the present invention was assessed using the following representative test method. 1. Application step Glass and metal test sample slides were soaked in a concentrated solution containing carboxy methyl cellulose (CMC) at a level of 0.0034% active CMC by weight. The test sample slides were soaked in the above solution for 30 mins before being removed and allowed to dry overnight.

2. 'In-use¹ soiling step The pre-treated test sample slides were then soiled using a variety of soil types, including a boiled spaghetti solution, egg and cheese soils. The spaghetti solution, egg and cheese soils were painted onto the slides. In addition, 70 g of DIN soil (comprising Breakfast oats, PG (tradename) loose leaf tea, frozen spinach, UHT full cream milk, butter, Tyne Brand (tradename) mince and onions in gravy, 12 eggs in 4 litres of Newcastle city water) was added. The soiled test sample slides were accurately weighed using a Sartarius BA61™ electronic balance linked to a data handling package on an standard 486 computer for subsequent processing.

3. Washing step The test sample slides were then washed in a standard dishwashing machine, preferably Hotpoint 7883 (tradename), on an economy wash cycle at 55°C using Newcastle City water of hardness 9 grains per gallon (1.26 mmol Ca^{2 +}/litre). 20 g of detergent was added by way of a standard dispenser mechanism.

The test sample slides were removed after 1 wash and 1 rinse cycle and subsequently oven dried at 100°C. The test samples were then reweighed. The percentage soil removal is expressed using the following formula:

Post-soiling weight - Post-washing weight 100% Post-soiling weight

Soil Type Detergent A Detergent B

% Removal % Removal

Spaghetti soil 78.7 97.7

Cheese soil 42.9 91.8

^E8g 41.5 52.1 It is apparent from the above results that the inclusion of cellulose ether material in detergent formulation B, increases the percentage removal of soil from the surface of tableware.

Claims

WHAT IS CLAIMED IS:

1. The use of cellulose ether material as an agent enabling the improved release of soils from tableware when employed in a method comprising the steps of

(i) applying a coating of said cellulose ether to said tableware;

(ii) 'in use' soiling of the coated tableware; and

(iii) washing of the tableware, thereby removing said coating and soils.

2. The use according to Claim 1 , wherein the cellulose ether material is selected from the group of general formula:

R is hydrogen, an alkyl or a carboxy alkyl group n is 100-10000 degree of substitution (ds) is between 0 and 3.0 degree of polymerisation (dp) is more than 100 molecular weight of between 20 000 and 150 000

3. The use according to either Claim 1 or 2, wherein the cellulose ether is either methyl cellulose or carboxy methyl cellulose.

4. The use according to any of Claims 1 to 3, wherein the application step comprises soaking the tableware in a solution containing between 0.0001 % and 0.1 %, preferably 0.0005% and 0.01 % , most preferably 0.001 % and 0.005% by weight active cellulose ether.

5. The use according to Claims 1 to 4, wherein the application step comprises treating the tableware with a detergent solution additionally containing between 0.0001 % and 0.1 % , preferably 0.0005% and 0.01 %, most preferably 0.001 % and 0.005% by weight active cellulose ether.

6. The use according to any of Claims 1 to 5, wherein said washing of the tableware is by a machine washing method.