The invention relates to detergent compositions containing amphoteric polymers to control the deposition of lime soap, particularly machine dishwashing compositions containing lipolytic enzymes.

A critical criteria for an effective machine dishwashing composition is the appearance of both the washed glassware and plastic articles to the consumer. Spotting and filming of such tableware, when washed with commercial products, generally results from mineral deposition during the evaporation of undrained wash solution in the drying step. The deposited minerals are from many sources, including salts of ingredients in the product formulations, calcium carbonate from temporary water hardness, and suspended soil.

The deposition on the surfaces of the washed articles make them look dull due to the presence of spots, streaks or surface covering film. The most intense spotting problems are related to the deposition of hydrophobic soil fragments. In the final rinse stage, this hydrophobic soil is thought to break-up the water film, leaving droplets behind on the tableware which result in mineral deposits observed as white spots upon evaporation of the water component.

A prior art solution to the removal of these white mineral spots has been the addition of a rinse aid composition to the rinsing water of the machine cycle. Although the visual appearance of the washed tableware is improved, some spotting, but especially mineral film formation has still been observed even with the use of this additional product. Moreover, use of a rinse aid is inconvenient to the consumer.

The major fraction of the hydrophobic soil fragments that are present on washed tableware is believed to be triglyceride and fatty ester soil. Consequently, machine dishwashing and rinse aid compositions incorporating lipolytic enzymes which assist in breaking down these soils have been described in EP-A-346,136 and EP-A-271,155. Although lipolytic enzymes can reduce the formation of mineral spots due to hydrophobic soil fragments, the enzymes can also cause a different type of white deposits to build up on hydrophobic surfaces such as plastics. These fatty deposits are due to precipitation of lime soaps which are formed from the mixture of calcium and magnesium ions in the wash water with fatty acids, which are liberated from the triglyceride and fatty ester soils by the action of the lipolytic enzymes. The higher the level of fatty soil present in the dishwasher, the worse the problem of lime soap deposition.

Prior art solutions to these problems include formulations of machine dishwashing compositions incorporating certain lime soap dispersants with lipolytic enzymes as described in WO-94/07984 and WO-94/07985 (Proctor & Gamble). Tableware washed with compositions containing lipases and these lime soap dispersants have been observed to have low lime soap film scores (i.e. little to no filming is observed). However, a large number of white mineral spots on the washed articles have been observed. It is thus believed that the lime soap dispersants described in these publications actually inhibit the action of the lipase.

Hydrophobically modified copolymers, of especially acrylic acid, have been described in copending Gordon et al.; U.S. Serial No. 08/457,690 for incorporation in machine dishwashing compositions. Calcium soap deposition is reduced by the presence of these polymers.

US-A-4,891,149 describes polymeric lime soap dispersants which consist of copolymers and water soluble salts of copolymers of acrylic acid, methacrylic acid and mixtures thereof and acrylamide, alkyl or alkylol substituted acrylamide, or mixture of said acrylamides. Optionally, enzymes may also be added to the formulations.

US-A-5,308,532 (Rohm & Haas) describes aminoacryloyl - containing terpolymers which are useful for reducing mineral spotting and filming of tableware. Thus, the detergent formulation acts by preventing hydrophobic deposits on glassware and does not address the issue of preventing lime soap deposition. The use of lipolytic enzymes in combination with such terpolymers to control the deposition of lime soaps is neither taught nor suggested.

It is therefore an object of the present invention to provide machine dishwashing compositions and methods of using them to prevent lime soap deposition on washed tableware.

Another object of the invention is to selectively combine lipolytic enzymes with particular amphoteric polymers in a detergent composition to control lime soap deposition and virtually prevent spotting and lime soap filming on cleaned tableware.

Accordingly, the present invention provides a machine washing composition comprising:

• (a) an effective amount of a amphoteric polymer wherein in a 1% aqueous wash liquor having a pH of about 7 or greater, positive charges on the polymer comprise between 1% and 50%, preferably between 2% and 20%, most preferably between 5 and 15% of the total charges on the polymer having a formula selected from:
  • i) A_xB_y C_z where in a 1% aqueous wash liquor pH A is an anionic moiety, B is a cationic moiety and C is an anionic, cationic, amphoteric or uncharged moiety and mixtures thereof, x, y, and z refer to mole percentages, x is 50-99%, preferably 80-98%, most preferably 85-95%, and y is 1-50%, preferably 2-20%, most preferably 5-15% and z is 0 to 25%, preferably 0 to 18%; or
  • ii) D_dE_f where at the wash pH D is an amphoteric moiety, E is an anionic, cationic, or uncharged moiety and mixture thereof, d and f refer to mole percentages, and d is 1-100% and f is 0-99% provided the above stated charge distribution is satisfied;
• (b) 0.01% to about 4 wt. % of a lipolytic enzyme; and
• (c) about 1 to about 75% by wt. of a builder material.

A bleaching agent is optionally included.

The amphoteric polymers incorporated in the compositions of the invention are present in an effective amount, preferably about 0.1 to about 25%, more preferably from about 1 to about 15%, most preferably from about 2 to about 10% by wt.

Wash pH is defined as the measured pH of a 1% aqueous solution of dishwasher water in the main wash cycle after addition and dissolution of the detergent composition. At a wash pH preferably between about 7 and about 12, most preferably between about 8 and about 11, positive charges on the polymer comprise between 1% and 50%, preferably between 2% and 20%, most preferably between 5 and 15% of the total charges on the polymer.

The amphoteric polymers are addition polymers which may be prepared by (1) copolymerizing selected monomers which are anionic at the wash pH with selected monomers which are cationic at the wash pH, or (2) by polymerizing selected amphoteric monomers.

A first means of preparing the amphoteric polymers which are useful in the invention consists of copolymerizing from about 50 to about 99% , preferably from about 80 to about 98%, most preferably from about 85 to about 98% by wt. of the anionic monomer (A) with about 1 to about 50%, preferably from about 2 to about 20%, most preferably from about 2 to about 15% by wt. of the cationic monomer. Optionally, a charged or uncharged moiety (C) is also copolymerized.

The monomers (A) used to prepare the amphoteric polymers are substituted vinyl compounds which have anionic character at wash pH. Preferred monomers are substituted vinyl compounds of formula l wherein R¹, R², and R³ are independently a hydrogen, C₁ to C₃ alkyl, a carboxylate group or a carboxylate group substituted with a C₁ to C₃₀ straight or branched alkyl, aromatic heterocycle or a polyalkylamine oxide with the requirement that at least one of R¹, R², or R³ must be a carboxylate or substituted carboxylate;

Preferred monomers include acrylic acid, methacrylic acid, maleic acid, α-ethacrylic acid, β,β,-dimethacrylic acid, methylenemalonic acid, vinylacetic acid, allylacetic acid, ethylidineacetic acid, propylidineacitic acid, crotonic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid and the like. Most preferred monomers include acrylic acid, methacrylic acid, and maleic acid.

The monomers (B) used to form the amphoteric polymers of the invention which have cationic character at wash pH are substituted vinyl compounds of formula ll wherein R⁴ is a hydrogen, aromatic, heterocycle or a polyalkylamine oxide; R⁵ is a hydrogen or a C₁ to C₃₀ straight or branched alkyl; and Q is a nitrogen-containing organic radical, said radical having a pKa value of > 7. methacrylate, dialkylaminoalkyl acrylate, dialkylaminoalkyl methacrylamide and dialkylaminoalkyl acrylamide.

The monomers of formula II are preferably quaternized wherein Q is preferably selected from the group consisting of formula lll

        ―CH₂N⁺(CH₃)₂CH₂CH=CH₂ X^-     (III)

wherein X^- is any suitable counterion such as halogen, hydroxide, sulfate, hydrosulfate, phosphate, formate and acetate or,
a compound of formula lV

        -Z-CH₂-CR⁶R⁷(CH₂)_mN⁺R⁸R⁹R¹⁰     (IV)

wherein Z is selected from the group consisting of O, COO and CONR¹¹ in which R¹¹ is a hydrogen or a C₁ to C₃ alkyl group; R⁶ and R⁷ are each independently selected from the group consisting of hydrogen, C₁ to C₄ alkyl or R⁶ and R⁷ taken together form a C₃ to C₇ aliphatic heterocycle; m is 0 to 2 provided that when m is 0 a C-N bond is present in lieu of the (CH₂)_m group and R⁸, R⁹, and R¹⁰ are each independently selected from a group consisting of hydrogen or a C₁ to C₄ alkyl; or R⁸ and R⁹ are taken together with the nitrogen to which they are attached to form a 3 to 7 membered non-aromatic nitrogen heterocycle; and X is any suitable counterion such as a halogen, hydroxide, sulfate, hydrosulfate, phosphate, formate and acetate.

Preferred examples of the quaternized monomers are (3-acrylamidopropyl) trimethylammonium chloride (APTAC), (3-methacrylamidopropyl) trimethylammonium
chloride (MAPTAC), and dimethyldiallylammonium chloride (DMDAC). Other suitable examples include such materials as vinylbenzyltrialkylammonium salts and the like.

Monomers (C) which are anionic or cationic are selected from compounds of formula I or II, respectively.

Amphoteric monomers (C) may be selected from compounds of formula V described below. wherein, R¹² is a C₃ to C₆ monoethylenically unsaturated carboxylate; R¹³ and R¹⁴ each independently represent hydrogen or a C₁ to C₃ alkyl; R¹⁵ and R¹⁶ each independently represent a hydrogen or a C₁ to C₃ alkyl; x is 1 to 3; and y is 1 to 3.

Suitable carboxylates represented by R¹² include, but are not limited to, acrylic acid, methacrylic acid, α-ethacrylic acid, β,β,-dimethacrylic acid, methylenemalonic acid, vinylacetic acid, allylacetic acid, ethylidineacetic acid, propylidineacitic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, and alkali metal and ammonium salts thereof.

Preferably, the unsaturated carboxylic acid is acrylic or methacrylic acid.

Uncharged monomers (C) are selected from C₁-C₄ alkyl esters of acrylic acid, methacrylic acid, and itaconic acid; C₁-C₄ hydroxyalkyl esters of acrylic acid, methacrylic acid, and itaconic acid, alkylene oxide esters of acrylic acid, methacrylic acid, and itaconic acid having 1-20 alkylene oxide repeat units; and C₁-C₂₀ EO1-EO20 ethoxyalkyl esters of acrylic acid, methacrylic acid, and itaconic acid; styrene; vinyl alcohol; vinyl acetate; methyl vinyl ether; and allyl alcohols. Preferably the uncharged monomer is C1-C4 alkyl ester of acrylic acid, methacrylic acid, or itaconic acid, C1-C4 hydroxyalkyl ester of acrylic acid, methacrylic acid, or itaconic acid, or C1-C20 EO1-EO20 ethoxyalkyl ester of acrylilc acid, methacrylic acid, or itaconic acid.
If these optional monomers (C) are present they should be present only in an amount of less than 25% of the total monomer distribution.

Preferably the amphoteric polymers (A_xB_yC_z wherein z is 0) produced from the monomers of formulas l and ll are formed of monomers of acrylic acid polymerized with quaternized basic monomers.

A second means of obtaining amphoteric polymers useful in the invention is the polymerization of an amphoteric monomer (D) having a formula (V) as described above.

The amphoteric monomers of formula (V) may be homopolymerized or copolymerized with non-amphoteric polymerizable monomers (E) in an amount from about 0 to about 99% by wt., preferably from 0 to about 75% by wt., with the requirement that the previously defined polymer charge distribution be satisfied.

Suitable anionic, and cationic monomers from which the moiety E is selected are represented by formulas I and II. Uncharged monomers are selected from C1-C4 alkyl esters of acrylic acid, methacrylic acid, and itaconic acid; C1-C4 hydroxyalkyl esters of acrylic acid, methacrylic acid, and itaconic acid, alkylene oxide esters of acrylic acid, methacrylic acid, and itaconic acid having 1-20 alkylene oxide repeat units; and C1-C20 EO1-EO20 ethoxyalkyl esters of acrylic acid, methacrylic acid, and itaconic acid; styrene; vinyl alcohol; vinyl acetate; methyl vinyl ether; and allyl alcohols. Preferably the uncharged monomer is C1-C4 alkyl ester of acrylic acid, methacrylic acid, or itaconic acid, C1-C4 hydroxyalkyl ester of acrylic acid, methacrylic acid, or itaconic acid, or C1-C20 EO1-EO20 ethoxyalkyl ester of acrylilc acid, methacrylic acid, or itaconic acid.

Suitable examples of amphoteric polymers include, but are not limited to, a copolymer of acrylic acid and 3-acrylamidopropyl trimethylammonium chloride as described in EP-A- 560, 519 Rohm and Haas, and EXP-2072 and EXP-2075 (terpolymers of acrylic acid, dimethyldiallylammonium chloride and C14-20 EO 20 itaconate ester available from Alco). Preferably, the polymers are the copolymers of acrylic acid and 3-acrylamido-propyl trimethylammonium chloride.

Lipolytic enzymes are an essential component of the machine washing compositions of the invention. They are present at levels of active enzyme of from 0.01 to 4% by wt., preferably 0.01% to 3% by wt., most preferably from 0.05% to 1.5% by wt. of the composition, based on lipolytic activity of 100 LU/mg. Lipolytic activity is commonly defined by the amount of titratable fatty acid liberated from triglyceride under specified conditions. One lipase unit (LU) of activity is equivalent to liberation of one micromole of butyric acid per minute from an emulsion of tributyrin and gum arabic in the presence of Ca⁺⁺ and NaCl at 30 Deg. C and pH 7.

Lipases facilitate the degradation or alteration of soils and stains comprising triglycerides or fatty esters. Lipases suitable for use herein include those of animal, plant and microbiological origin. Suitable lipases are also found in many strains of bacteria and fungi. For example, lipases suitable for use herein can be obtained from Pseudomonas, Aspergillus, Staphylococcus, Toxins, Mycobacterium Tuberculosis, Mycotorula Lipolytica and Sclerotinia microorganisms. Lipases from chemically or genetically modified mutants are also included herein. Mixtures of lipase from various strains are also included herein.

Suitable animal lipases are found in the body fluids and organs of many species. A preferred class of animal lipase herein are the pancreatic lipases.

A preferred lipase herein is obtained by cloning the gene from Humicola lanuginosa and expressing the gene in Aspergillus oryza, as host, as described in EP-A-0258068, which is commercially available from Novo Industri A/S, Denmark, under the tradename Lipolase.

Tradenames of other suitable lipases are Lipomax, ex. Gist Brocades (now Genencor), the Netherlands and Lipase G-1000, ex. Solvay Enzymes, USA.

Hypohalite may be used as long as the bleach is added to avoid deactivation of the enzymes of the formulation. A preferred method of preventing enzyme deactivation is encapsulation of the bleach is described in US-A-5,200,236, herein incorporated by reference. In the patented method, the bleaching agent is encapsulated as a core in a paraffin wax material having a melting point from about 40°C to 50°C. The wax coating has a thickness of from 100 to 1500 microns.

Suitable reactive chlorine or bromine oxidizing materials are chloro and bromo amides such as trichloroisocyanuric, tribromoisocyanuric, dibromoisocyanuric and dichloroisocyanuric acids, and salts thereof with water solubilizing cations such as potassium and sodium. Hydantoin compounds such as 1,3-dichloro-5,5-dimethylhydantoin are also quite suitable.

The oxygen bleaching agents of the compositions include organic peroxy acids and diacylperoxides. Typical monoperoxy acids useful herein include alkyl peroxy acids and aryl peroxy acids such as:

• i) peroxybenzoic acid and ring-substituted peroxybenzoic acids, e.g., peroxy-alpha-naphthoic acid, and magnesium monoperoxyphthalate
• ii) aliphatic and substituted aliphatic monoperoxy acids, e.g., peroxylauric acid, epsilon-phthalimido-peroxyhexanoic acid and o-carboxybenzamido peroxyhexanoic acid, N-nonylamidoperadipic acid and N-nonylamidopersuccinic acid.
• iii) Cationic peroxyacids such as those described in US-A-5,422,028, US-A-5,294,362; and US-A-5,292,447, Atty. Docket No. 95-0394-UNI; Case 7392, Oakes et al.; and U.S. S/N 08/210,973, Oakes et al., herein incorporated by reference.
• iv) Sulfonyl peroxyacids such as compounds described in US-A-5,039,447 (Monsanto Co.), herein incorporated by reference.

Typical diperoxy acids useful herein include alkyl diperoxy acids and aryl diperoxy acids, such as:

• v) 1,12-diperoxydodecanedioic acid
• vi) 1,9-diperoxyazelaic acid
• vii) diperoxybrassylic acid; diperoxysecacic acid and diperoxy-isophthalic acid
• viii) 2-decyldiperoxybutan-1,4-dioic acid
• ix) N,N¹-terephthaloyl-di(6-aminopercaproic acid).

A typical diacylperoxide useful herein includes dibenzoylperoxide.

Inorganic peroxygen compounds are also suitable for the present invention. Examples of these materials useful in the invention are salts of monopersulfate, perborate monohydrate, perborate tetrahydrate, and percarbonate.

Preferred oxygen bleaching agents include epsilon-phthalimido-peroxyhexanoic acid, o-carboxybenzaminoperoxyhexanoic acid, and mixtures thereof. Most preferred bleaching agents include perborate monohydrate and percarbonate.

The oxygen bleaching agent is present in the composition in an amount from about of 1 to 20 weight percent, preferably 1 to 15 weight percent.

The oxygen bleaching agent may be incorporated directly into the formulation or may be encapsulated by any number of encapsulation techniques known in the art to produce stable capsules in alkaline liquid formulations.

Suitable peroxygen peracid precursors for peroxy bleach compounds have been amply described in the literature, including GB Nos. 836,988; 855,735; 907,356; 907;358; 907,950; 1,003,310 and 1,246,339; US-A-3,332,882 and US-A-4,128,494.

Typical examples of precursors are polyacylated alkylene diamines, such as N,N,N¹,N¹-tetraacetylethylene diamine (TAED) and N,N,N¹,N¹-tetraacetylmethylene diamine (TAMD); acylated glycolurils, such as tetraacetylglycoluril (TAGU); triacetylcyanurate, sodium sulfophenyl ethyl carbonic acid ester, sodium acetyloxybenene sulfonate (SABS), sodium nonanoyloxy benzene sulfonate (SNOBS) and choline sulfophenyl carbonate. Peroxybenzoic acid precursors are known in the art, e.g., as described in GB-A-836,988. Examples of suitable precursors are phenylbenzoate; phenyl p-nitrobenzoate; o-nitrophenyl benzoate; o-carboxyphenyl benzoate; p-bromophenylbenzoate; sodium or potassium benzoyloxy benzene-sulfonate; and benzoic anhydride.

Preferred peroxygen bleach precursors are sodium p-benzoyloxybenzene sulfonate, N,N,N¹,N¹-tetraacetylethylene diamine, sodium nonanoyloxybenzene sulfonate and choline sulfophenyl carbonate.

Bleach catalysts which may also be used in the detergent compositions include maganese catalysts such as those described in US-A-5,246,621.

The compositions of this invention contains either organic builders, particularly carboxylates, or inorganic builders, particularly phosphorous containing compounds.

Examples of phosphorus-containing inorganic builders include the water-soluble salts, especially alkali metal pyrophosphates, orthophosphates and polyphosphates, particularly ammonium and alkanol ammonium salts, and phosphonates. Particularly preferred phosphate builders include sodium and potassium tripolyphosphates, pyrophosphates, hexametaphosphates and trimetaphosphates. When phosphate builders are incorporated into the formula, they are present in an amount of about 10 to about 75% by wt., most preferably 15 to about 60 wt. %.

Non-phosphorus-containing inorganic builders may be additionally used such as water-soluble alkali metal carbonates, bicarbonates, sesquicarbonates, borates, silicates, layered silicates such as SKS-6 ex Hoechst, metasilicates, phytic acid, borate and crystalline and amorphous aluminosilicates. Specific examples include sodium carbonate (with or without calcite seeds), potassium carbonate, sodium and potassium bicarbonates, silicates, including layered silicates and zeolites.

Organic detergent builders useful in the present invention include a variety of polycarboxylate compounds. As used herein "polycarboxylate" refers to compounds having a plurality of carboxylate groups, preferably at least three (3) carboxylates. Monomeric or polymeric carboxylates are preferred. Examples of organic builders include alkali metal citrates, succinates, malonates, fatty acid sulfonates, fatty acid carboxylates, nitrilotriacetates, phytates, phosphonates, alkanehydroxyphosphonates, oxydisuccinates, alkyl and alkenyl disuccinates, oxydiacetates, carboxymethyloxy succinates, ethylenediamine tetraacetates, tartrate monosuccinates, tartrate disuccinates, tartrate monoacetates, tartrate diacetates, oxidized starches, oxidized heteropolymeric polysaccharides, and polyhydroxysulfonates.

Polycarboxylates include polyacrylates, polymaleates, polyacetates, polyhydroxyacrylates, polyacrylate/polymaleate and polyacrylate/ polymethacrylate copolymers, acrylate/maleate/vinyl alcohol terpolymers, aminopolycarboxylates and polyacetal carboxylates, and polyaspartates and mixtures thereof. Such carboxylates are described in US-A-4,144,226, US-A-4,146,495 and US-A-4,686,062, herein incorporated by reference.

Alkali metal citrates, nitrilotriacetates, oxydisuccinates, polyphosphonates and acrylate/maleate copolymers and acrylate/maleate/vinyl alcohol terpolymers are especially preferred organic builders.

When the builder is comprised primarily of either monomeric or polymeric carboxylates or mixtures thereof the builder should be present in an amount of 10 to 60 wt. %, most preferably 15 to 50 wt. %.

The foregoing detergent builders are meant to illustrate but not limit the types of builders that can be employed in the present invention.

Additional enzymes capable of facilitating the removal of soils from a substrate may also be present in an amount of up to about 10% by wt., preferably 1 to about 5 wt. %. Such enzymes include proteases (e.g., Alcalase®, Savinase® and Esperase® from Novo Industries A/S and Purafect OxP®, ex. Genencor) and amylases (e.g., Termamyl® and Duramyl® from Novo Industries and Purafect OxAm®, ex. Genencor).

Minor amounts of various other components may optionally be present in the cleaning composition. These include filler, non-carboxylic thickening agents, defoamer, bleach scavengers including but not limited to sodium bisulfite, reducing sugars, and short chain alcohols; solvents and hydrotropes such as ethanol, isopropanol and xylene sulfonates; enzyme stabilizing agents; soil suspending agents; antiredeposition agents; anti-corrosion agents, such as benzotriazole and isocyanuric acid described in US-A-5,374,369; ingredients to enhance decor care such as certain aluminum salts described in U.S. Serial No. 08/444,502 and 08/444,503, herein incorporated by reference; colorants; perfumes; opacifiers such as titanium dioxide; and other functional additives.

The detergent compositions herein may also optionally contain one or more transition metal (such as Fe, Mn, or Cu) chelating agents. Such chelating agents can be selected from the group consisting of amino carboxylates, amino phosphonates, polyfunctionally-substituted aromatic chelating agents and mixtures therein. Without intending to be bound by theory, it is believed that the benefit of these materials is due in part to their exceptional ability to remove transition metal ions such as Fe, Mn, and Cu from washing solutions by formation of soluble chelates.

Amino carboxylates useful as optional chelating agents include ethylenediaminetetraacetates; N-hydroxyethylethylenediaminetriacetates; nitrilotriacetates; ethylenediamine tetraproprionates; triethylenetetraaminehexaacetates; diethylenetriaminepentaacetates; ethylenediamine disuccinate; ethanoldiglycines; alkali metal, ammonium, and substituted ammonium salts therein and mixtures therein.

Phosphonates and amino phosphonates are also suitable for use as chelating agents in the compositions of the invention when at least low levels of total phosphorus are permitted in detergent compositions, and include ethylenediaminetetrakis (methylenephosphonates), nitrilotris (methylenephosphonates) and diethylenetriaminepentakis (methylenephosphonates).

Preferably, these phosphonates and aminophosphonates do not contain alkyl or alkenyl groups with more than about 6 carbon atoms.

Polyfunctionally-substituted aromatic chelating agents are also useful in the compositions herein. See US-A-3,812,044, Preferred compounds of this type in acid form are dihydroxydisulfobenzenes such as 1,2-dihydroxy-3,5-disulfobenzene.

If utilized, these chelating agents will generally comprise from about 0.1% to about 10% by weight of the detergent compositions herein. More preferably, if utilized, the chelating agents will comprise from about 0.1% to about 3.0% by weight of such composition.

Scale formation on dishes and machine parts is an important problem that needs to be resolved or at least mitigated in formulating a machine warewashing product, especially in the case of low-phosphate (e.g. less than the equivalent of 20% by weight, particularly 10% by weight of sodium triphosphate) and phosphate-free machine warewashing compositions, particularly zero-P machine warewashing compositions.

In order to reduce this problem, co-builders, such as polyacrylic acids or polyacrylates (PAA), acrylate/maleate copolymers, polyaspartates, ethylenediamine disuccinate and the various organic polyphosphonates, e.g. Dequest series, may be incorporated in one or more system components. For improved biodegradability, (as such co-builders), the block co-polymers of formula (I) as defined in published PCT patent specification WO 94/17170 may also be used. In any component, the amount of anti-scalant may be in the range of from 0.5 to 10, preferably from 0.5 to 5, and more preferably from 1 to 5% by weight.

Useful surfactants include anionic, nonionic, cationic, amphoteric, amphoteric types and mixtures of these surface active agents. It is understood that surfactants should be selected and used at such levels as conventionally known in the art so as not to deactivate enzymes in the formula. Such surfactants are well known in the detergent art and are described at length in "Surface Active Agents and Detergents", Vol. II, by Schwartz, Perry & Birch, Interscience Publishers, Inc. 1959, herein incorporated by reference.

Surfactants, if present in the composition, may be selected from the following:

Anionic synthetic detergents can be broadly described as surface active compounds with one or more negatively charged functional groups. An important class of anionic compounds are the water-soluble salts, particularly the alkali metal salts, of organic sulfur reaction products having in their molecular structure an alkyl radical containing from about 6 to 24 carbon atoms and a radical selected from the group consisting of sulfonic and sulfuric acid ester radicals.

• Primary Alkyl Sulfates
  
          R¹⁷OSO₃M
  
  where R¹⁷ is a primary alkyl group of 8 to 18 carbon atoms and M is a solubilizing cation. The alkyl group R¹⁷ may have a mixture of chain lengths. It is preferred that at least two thirds of the R¹⁷ alkyl groups have a chain length of 8 to 14 carbon atoms. This will be the case if R¹⁷ is coconut alkyl, for example. The solubilizing cation may be a range of cations which are in general monovalent and confer water solubility. Alkali metal, notably sodium, is especially envisaged. Other possibilities are ammonium and substituted ammonium ions, such as trialkanolammonium or trialkylammonium.
• Alkyl Ether Sulfates
  
          R¹⁷O(CH₂CH₂O)_nSO₃M
  
  where R¹⁷ is a primary alkyl group of 8 to 18 carbon atoms, n has an average value in the range from 1 to 6 and M is a solubilizing cation. The alkyl group R¹⁷ may have a mixture of chain lengths. It is preferred that at least two thirds of the R¹⁷ alkyl groups have a chain length of 8 to 14 carbon atoms. This will be the case if R¹⁷ is coconut alkyl, for example. Preferably n has an average value of 2 to 5.
• Fatty Acid Ester Sulfonates
  
          R¹⁸CH(SO₃M)CO₂R¹⁹
  
  where R¹⁸ is an alkyl group of 6 to 16 atoms, R¹⁹ is an alkyl group of 1 to 4 carbon atoms and M is a solubilizing cation. The group R¹⁸ may have a mixture of chain lengths. Preferably at least two thirds of these groups have 6 to 12 carbon atoms.

This will be the case when the moiety R¹⁸CH(-)CO₂(-) is derived from a coconut source, for instance. It is preferred that R¹⁹ is a straight chain alkyl, notably methyl or ethyl.

• Alkyl Benzene Sulfonates
  
          R²⁰ArSO₃M
  
  where R²⁰ is an alkyl group of 8 to 18 carbon atoms, Ar is a benzene ring (C₆H₄) and M is a solubilizing cation. The group R²⁰ may be a mixture of chain lengths. Straight chains of 11 to 14 carbon atoms are preferred.
• Organic phosphate based anionic surfactants include organic phosphate esters such as complex mono- or diester phosphates of hydroxyl- terminated alkoxide condensates, or salts thereof. Included in the organic phosphate esters are phosphate ester derivatives of polyoxyalkylated alkylaryl phosphate esters, of ethoxylated linear alcohols and ethoxylates of phenol.

Also included are nonionic alkoxylates having a sodium alkylenecarboxylate moiety linked to a terminal hydroxyl group of the nonionic through an ether bond. Counterions to the salts of all the foregoing may be those of alkali metal, alkaline earth metal, ammonium, alkanolammonium and alkylammonium types.

Particularly preferred anionic surfactants are the fatty acid ester sulfonates with formula:

        R¹⁸CH(SO₃M)CO₂R¹⁹

where the moiety R¹⁸CH(-)CO₂(-) is derived from a coconut source and R¹⁹ is either methyl or ethyl.

Nonionic surfactants can be broadly defined as surface active compounds with one or more uncharged hydrophilic substituents. A major class of nonionic surfactants are those compounds produced by the condensation of alkylene oxide groups with an organic hydrophobic material which may be aliphatic or alkyl aromatic in nature. The length of the hydrophilic or polyoxyalkylene radical 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. Illustrative, but not limiting examples, of various suitable nonionic surfactant types are:

• polyoxyethylene or polyoxypropylene condensates of aliphatic carboxylic acids, whether linear- or branched-chain and unsaturated or saturated, containing from about 8 to about 18 carbon atoms in the aliphatic chain and incorporating from about 2 to about 50 ethylene oxide and/or propylene oxide units. Suitable carboxylic acids include "coconut" fatty acids (derived from coconut oil) which contain an average of about 12 carbon atoms, "tallow" fatty acids (derived from tallow-class fats) which contain an average of about 18 carbon atoms, palmitic acid, myristic acid, stearic acid and lauric acid,
• polyoxyethylene or polyoxypropylene condensates of aliphatic alcohols, whether linear- or branched-chain and unsaturated or saturated, containing from about 6 to about 24 carbon atoms and incorporating from about 2 to about 50 ethylene oxide and/or propylene oxide units. Suitable alcohols include "coconut" fatty alcohol, "tallow" fatty alcohol, lauryl alcohol, myristyl alcohol and oleyl alcohol.

Ethoxylated fatty alcohols may be used alone or in admixture with anionic surfactants, especially the preferred surfactants above. The average chain lengths of the alkyl group R²¹ in the general formula: R²¹O(CH₂CH₂O)_nH is from 6 to 24 carbon atoms. Preferably the group R²¹ may have chain lengths in a range from 9 to 18 carbon atoms.

The average value of n should be at least 2. The numbers of ethylene oxide residues may be a statistical distribution around the average value. However, as is known, the distribution can be affected by the manufacturing process or altered by fractionation after ethoxylation. Particularly preferred ethoxylated fatty alcohols have a group R²¹ which has 9 to 18 carbon atoms while n is from 2 to 8.

Also included within this category are nonionic surfactants having a formula: wherein R²² is a linear alkyl hydrocarbon radical having an average of 6 to 18 carbon atoms, R²³ and R²⁴ are each linear alkyl hydrocarbons of about 1 to about 4 carbon atoms, x is an integer of from 1 to 6, y is an integer of from 4 to 20 and z is an integer from 4 to 25.

One preferred nonionic surfactant of the above formula is Poly-Tergent SLF-18® a registered trademark of the Olin Corporation, New Haven, Conn. having a composition of the above formula where R²² is a C₆-C₁₀ linear alkyl mixture, R²³ and R²⁴ are methyl,
x averages 3, y averages 12 and z averages 16. Another preferred nonionic surfactant is wherein R²⁵ is a linear, aliphatic hydrocarbon radical having from about 4 to about 18 carbon atoms including mixtures thereof; and R²⁶ is a linear, aliphatic hydrocarbon radical having from about 2 to about 26 carbon atoms including mixtures thereof; j is an integer having a value of from 1 to about 3; k is an integer having a value from 5 to about 30; and z is an integer having a value of from 1 to about 3. Most preferred are compositions in which j is 1, k is from about 10 to about 20 and z is 1. These surfactants are described in WO 94/22800. Other preferred nonionic surfactants are linear fatty alcohol alkoxylates with a capped terminal group, as described in U.S. 4,340,766 to BASF.

Another nonionic surfactant included within this category are compounds of formula:

        R²⁷-(CH2CH2O)_qH

wherein R²⁷ is a C₆-C₂₄ linear or branched alkyl hydrocarbon radical and q is a number from 2 to 50; more preferably R²⁷ is a C₈-C₁₈ linear alkyl mixture and q is a number from 2 to 15.

• polyoxyethylene or polyoxypropylene condensates of alkyl phenols, whether linear- or branched-chain and unsaturated or saturated,containing from about 6 to 12 carbon atoms and incorporating from about 2 to about 25 moles of ethylene oxide and/or propylene oxide.
• polyoxyethylene derivatives of sorbitan mono-, di-, and tri-fatty acid esters wherein the fatty acid component has between 12 and 24 carbon atoms. The preferred sorbitan trilaurate, sorbitan monopalmitate, sorbitan tripalmitate, sorbitan monostearate, sorbitan monoisostearate, sorbitan tripalmitate, sorbitol tristearate, sorbitan monooleate, and sorbitan trioleate. The polyoxyethylene chains may contain between about 4 and 30 ethylene oxide units, preferably about 10 to 20. The sorbitan ester derivatives contain 1, 2 or 3 polyoxyethylene chains dependent upon whether they are mono-, di- or tri-acid esters.
• polyoxyethylene-polyoxypropylene block copolymers having formula:
  
          HO(CH₂CH₂O)_a(CH(CH₃) CH₂O)_b(CH₂CH₂O)_cH
  
  or
  
          HO(CH(CH₃)CH₂O)_d(CH₂CH₂O)_e(CH(CH₃)CH₂O)_fH
  
  wherein a, b, c, d, e and f are integers from 1 to 350 reflecting the respective polyethylene oxide and polypropylene oxide blocks of said polymer. The polyoxyethylene component of the block polymer constitutes at least about 10% of the block polymer. The material preferably has a molecular weight of between about 1,000 and 15,000, more preferably from about 1,500 to about 6,000. These materials are well-known in the art. They are available under the trademark "Pluronic" and "Pluronic R", a product of BASF Corporation.
• Amine oxides having formula:
  
          R²⁸R²⁹R³⁰N=O
  
  wherein R²⁸, R²⁹ and R³⁰ are saturated aliphatic radicals or substituted saturated aliphatic radicals. Preferable amine oxides are those wherein R²⁸ is an alkyl chain of about 10 to about 20 carbon atoms and R²⁹ and R³⁰ are methyl or ethyl groups or both R²⁸ and R²⁹ are alkyl chains of about 6 to about 14 carbon atoms and R³⁰ is a methyl or ethyl group.
• Amphoteric synthetic detergents may also be broadly described as derivatives of aliphatic and tertiary amines, in which the aliphatic radical may be straight chain or branched and wherein one of the aliphatic substituents contain from about 8 to about 18 carbons and one contains an anionic water-solubilizing group, i.e., carboxy, sulpho, sulphato, phosphato or phosphono. Examples of compounds falling within this definition are sodium 3-dodecylamino propionate and sodium 2-dodecylamino propane sulfonate.
• Amphoteric synthetic detergents can be broadly described as derivatives of aliphatic quaternary ammonium, phosphonium and sulphonium compounds in which the aliphatic radical may be straight chained or branched, and wherein one of the aliphatic substituents contains from about 8 to about 18 carbon atoms and one contains an anionic water-solubilizing group, e.g., carboxy, sulpho, sulphato, phosphato or phosphono. These compounds are frequently referred to as betaines. Besides alkyl betaines, alkyl amino and alkyl amido betaines are encompassed within this invention.
• Alkyl Glycosides
  
          R³¹O(R³²O)_n(Z¹)_p
  
  wherein R³¹ is a monovalent organic radical (e.g., a monovalent saturated aliphatic, unsaturated aliphatic or aromatic radical such as alkyl, hydroxyalkyl, alkenyl, hydroxyalkenyl, aryl, alkylaryl, hydroxyalkylaryl, arylalkyl, alkenylaryl, arylalkenyl, etc.) containing from about 6 to about 30 (preferably from about 8 to 18 and more preferably from about 9 to about 13) carbon atoms; R³² is a divalent hydrocarbon radical containing from 2 to about 4 carbon atoms such as ethylene, propylene or butylene (most preferably the unit (R³²O)_n represents repeating units of ethylene oxide, propylene oxide and/or random or block combinations thereof); n is a number having an average value of from 0 to about 12; Z¹ represents a moiety derived from a reducing saccharide containing 5 or 6 carbon atoms (most preferably a glucose unit); and p is a number having an average value of from 0.5 to about 10 preferably from about 0.5 to about 5 .

Examples of commercially available materials from Henkel Kommanditgesellschaft Aktien of Dusseldorf, Germany include APG® 300, 325 and 350 with R³¹ being C₉-C₁₁, n is 0 and p is 1.3, 1.6 and 1.8-2.2 respectively; APG® 500 and 550 with R³¹ is C₁₂-C₁₃, n is 0 and p is 1.3 and 1.8-2.2, respectively; and APG® 600 with R³¹ being C₁₂-C₁₄, n is 0 and p is 1.3.

While esters of glucose are contemplated especially, it is envisaged that corresponding materials based on other reducing sugars, such as galactose and mannose are also suitable.

The amount of surfactant present in the final formula should be from about 0.5 to about 30% by weight of the composition. The preferred range of surfactant is from 0.5 to 20% by weight, more preferably from 0.5 to 10% by weight.

An inert filler material which is water-soluble may also be present in cleaning compositions. This material should not precipitate calcium or magnesium ions at the filler use level. Suitable for this purpose are organic or inorganic compounds. Organic fillers include sucrose esters and urea. Representative inorganic fillers include sodium sulfate, sodium chloride and potassium chloride. A preferred filler is sodium sulfate. Its concentration may range from 0% to 20%, preferably from about 2% to about 10% by weight of the cleaning composition.

Thickeners are often desirable for liquid cleaning compositions. Thixotropic thickeners such as smectite clays including montmorillonite (bentonite), hectorite, saponite, and the like may be used to impart viscosity to liquid cleaning compositions. Silica, silica gel, and aluminosilicate may also be used as thickeners. Salts of polyacrylic acid (of molecular weight of from about 300,000 up to 6 million and higher), including polymers which are cross-linked may also be used alone or in combination with other thickeners. Use of clay thickeners for machine dishwashing compositions is disclosed for example in US-A-4,431,559; US-A-4,511,487; US-A-4,740,327; US-A-4,752,409. Commercially available synthetic smectite clays include Laponite supplied by Laporte Industries. Commercially available bentonite clays include Korthix H and VWH ex Combustion Engineering, Inc.; Polargel T ex American Colloid Co.; and Gelwhite clays (particularly Gelwhite GP and H) ex English China Clay Co. Polargel T is preferred as imparting a more intense white appearance to the composition than other clays. The amount of clay thickener employed in the compositions is from 0.1 to about 10%, preferably 0.5 to 5%. Use of salts of polymeric carboxylic acids is disclosed for example in GB-A-2,164,350, US-A-4,859,358 and US-A-4,836,948.

For liquid formulations with a "gel" appearance and rheology, particularly if a clear gel is desired, a chlorine-resistant polymeric thickener is particularly useful. US-A-4,260,528 discloses natural gums and resins for use in clear machine dishwashing detergents, which are not chlorine stable. Acrylic acid polymers that are cross-linked manufactured by, for example, B.F. Goodrich and sold under the trade name "Carbopol" have been found to be effective for production of clear gels, and Carbopol 940, 617 and 627, having a molecular weight of about 4,000,000 are particularly preferred for maintaining high viscosity with excellent chlorine stability over extended periods. Further suitable chlorine-resistant polymeric thickeners are described in US-A-4,867,896 incorporated by reference herein.

The amount of thickener employed in the compositions is from 0 to 5%, preferably 0.5-3%.

Stabilizers and/or co-structurants such as long-chain calcium and sodium soaps and C₁₂ to C₁₈ sulfates are detailed in US-A- 3,956,158 and US-A-4,271,030 and the use of other metal salts of long-chain soaps is detailed in US-A-4,752,409. Other co-structurants include Laponite and metal oxides and their salts as described in US-A-4,933,101, herein incorporated by reference. The amount of stabilizer which may be used in the liquid cleaning compositions is from about 0.01 to about 5% by weight of the composition, preferably 0.01-2%. Such stabilizers are optional in gel formulations. Co-structurants which are found especially suitable for gels include trivalent metal ions at 0.01-4% of the compositions, Laponite and/or water-soluble structuring chelants at 0.01-5%. These co-structurants are more fully described in the US-A-5,141,664, hereby incorporated by reference.

The formulations of the cleaning composition comprising surfactant may further include a defoamer. Suitable defoamers include mono-and distearyl acid phosphate, silicone oil and mineral oil. Even if the cleaning composition has only defoaming surfactant, the defoamer assists to minimize foam which food soils can generate.

The compositions may include 0.02 to 2% by weight of defoamer, or preferably 0.05-1.0%. Preferred antifoam systems are described in Angevaare et al.; US S/N 08/539,923, herein incorporated by reference.

The following examples will serve to distinguish this invention from the prior art and illustrate its embodiments more fully. Unless otherwise indicated, all parts, percentages and proportions referred to are by weights.

The lime soap dispersant properties of amphoteric polymers within the scope of the invention was compared to that of lime soap dispersants known in the prior art as described below.

The polymers were evaluated for their lime soap dispersing power value (LSDP), which is a conventional measurement of the effectiveness of a material for dispersing lime soap. The lime soap dispersing power value (LSDP) is defined as the (weight ratio of dispersant to sodium oleate X 100) based on the amount of dispersant required to disperse lime soap curd formed by 0.025g sodium oleate and 30mls of water of 333 ppm. CaCO₃ equivalent hardness. According to the test, a low LSDP value is an indication of an effective lime soap dispersant. A detailed description of the test is found in an article by H.C. Borghetty and C.A. Bergman, J. Am. Oil Chem. Soc., 27, pages 88-90, (1950). The materials used in the comparison are described in Table I below: MATERIALS SOURCE LSDP Amphoteric Polymer PC2 Supplied by Rohm & Haas 1.5 Amphoteric Polymer E-2072 Supplied By ALCO 1.5 Amphoteric Polymer E-2075 Supplied By ALCO 2.5 C13-C15 Alcohol Ethoxylate (12EO) Described in WO 94/07985 6.0 C12-C18 Alcohol Ethoxy Sulfate (3EO) Described in WO 94/07985 4.0 Polyacrylic Acid (200,000 MW) 22.0 Polyacrylic Acid (4,500 MW) Acusol 445 supplied by Rohm and Haas 15.0 Polyacrylic Acid/Acrylamide (200,000 MW) Supplied by Aldrich 17.5

As this example illustrates, amphoteric polymers within the scope of the invention are extremely effective lime soap dispersants in comparison to similar polymers outside the scope of the invention and in comparison to the preferred lime soap dispersants claimed in WO 94/07984 and WO 94/07985

The effect on glass and plasticware appearance of polymers and surfactants having an LSDP of less than 8 were compared by determining the effectiveness of each material in preventing the formation of mineral spots and films on clear glass tumblers and inhibition of lime soap filming on polyethylene plates when incorporated into the lipase containing base formulation.

A base machine dishwashing detergent composition was prepared as described in Table 2 below. INGREDIENTS % BY WT. STPP 51.0 Sodium silicate (PQ Britesil H20) 30.0 Sodium Percarbonate 9.0 TAED (tetraacetylethylenediamine) 3.6 Protease (Novo Savinase 6T) 3.0 Amylase (Novo Termamyl 60T) 1.8 Lipase (Novo Lipolase 100T) 0.2 Nonionic (BASF Plurafac LF403) 1.4 Lime soap dispersants were incorporated into the described base at a level of 5% by wt. in addition to the above composition.

A ten cycle test procedure was used as follows:

Five glass tumblers and two polyethylene plates were placed in a Bosch model 6082 dishwasher along with a ballast load of clean dishware consisting of 9 ceramic dinner plates, 2 ceramic tea cups, 2 stainless steel plates, and 2 melamine plates. Twenty grams of ASTM standard soil consisting of 80% margarine and 20% powdered milk was added to the dishwasher by spreading it onto the inside of the machine door. The 50° C. Economy wash setting was used, with water of 300/320 ppm. permanent/temporary hardness expressed as CaCO₃ equivalent (4:1 Ca/Mg ratio). 18.0 g detergent was added at the start of the main wash, along with lipase (Lipolase 100T ex. Novo) and selected polymer (5% by wt. in addition to the detergent composition) as specified. At the end of each complete cycle, fresh soil and detergent were added and the process repeated for a total of ten washes.

At the end of this process the tumblers and polyethylene items were visually graded for spotting and filming. Grading scales of from 0 to 5 were used to measure film deposition, where a grade of 0 indicates no visible film and a grade of 5 indicates coverage with a very heavy, opaque film. When lipase is present in the detergent composition, a film buildup can occur on the hydrophobic polyethylene articles, caused primarily by precipitated Ca soap. Thus, film scores for the polyethylene articles give an indication of lime soap dispersant efficacy.

For spotting, the number of spots on each item was counted, with the average number of spots per article reported. The number of spots on the glass tumblers gives an indication of the effectiveness of the lipase. When lipase is present in the detergent composition, the lowest number of spots corresponds to the most effective lipase action.
The following spotting and filming grades were obtained (as noted, filming on polyethylene items in the presence of lipase is primarily caused by lime soap deposition): Composition Glass Tumblers Polyethylene Items mineral film lime soap film score # of spots film score # of spots (1) Base formulation 1.0 225 3.0 138 (2) Base + lipase, no dispersant 1.0 1 5.0 0 (3) Base + lipase + amphoteric polymer (PC2) 1.5 0 2.5 0 (4) Base + Lipase + C13-C15 EO12 alcohol ethoxylate 0.5 51 2.0 33 (5) Base + Lipase + C12-C15 EO3 alcohol ethoxysulfate 0.5 120 0.0 127

As this example demonstrates, addition of lipase to the base formulation results in a significant reduction in the number of spots on the glass tumblers (Composition 2). This is indicative of lipase functioning in the system. However, filming on polyethylene items is very high, due to lime soap deposition. Addition of an amphoteric polymer within the scope of the invention (Composition 3) significantly reduces the film score on polyethylene items, while the excellent glassware appearance produced by lipase is retained, as seen by the low spotting scores on the glass tumblers. In contrast, while the materials described in WO94/07984 and WO/07985 (incorporated in Compositions 4 and 5) reduce lime soap deposition, they also greatly reduce

The ability of amphoteric polymers to reduce lime soap deposition without inhibiting the antispotting benefit provided by lipase was further demonstrated as follows:

The ten wash cycle test procedure described in example 2 was followed. The base dishwashing detergent composition as described in Table 2 was used for this example, but was dosed at 26.0 g instead of the 18.0 g used in example 2. Amphoteric polymers were added to this composition at a level of 4%, as opposed to the 5% used in the previous example. All other test parameters were identical to those for example 1.

The following spotting and filming grades were obtained (as noted, filming on polyethylene items is primarily caused by lime soap deposition): Composition Glass Tumblers Polyethylene Items mineral film lime soap film score # of spots film score # of shots (1) Base + lipase, no dispersant 2.1 0 1.5 225 (2) Base + lipase + amphoteric polymer (PC2) 2.2 2 0 23 (3) Base + lipase + amphoteric polymer (Alco E-2072) 2.3 2 0.3 30 (4) Base + lipase + amphoteric polymer (Alco E-2075) 1.9 2 0.3 16

This example further illustrates the effectiveness of amphoteric polymers within the scope of the invention in improving glass and plasticware appearance by inhibiting the deposition of lime soap while maintaining the antispotting benefit provided by lipase.