WO1993018129A1

WO1993018129A1 - Low-dosage automatic dishwashing detergent with monopersulfate and enzymes

Info

Publication number: WO1993018129A1
Application number: PCT/US1993/001895
Authority: WO
Inventors: Frederick Anthony Hartman; Ronald Jay Rice; James Burckett-St.Laurent
Original assignee: The Procter & Gamble Company
Priority date: 1992-03-12
Filing date: 1993-03-05
Publication date: 1993-09-16
Also published as: CA2130465C; EP0630400A1; CA2130465A1

Abstract

Automatic dishwashing detergents are provided in convenient, compact form without chlorine bleaches or phosphate builders. Thus, monopersulfate bleach such as 2KHSO5.KHSO4.K2SO4 is used in combination with protease or amylase enzymes and acrylate organic dispersants to provide good cleaning of tableware. Weak builders such as citrate and pH-adjusting agents such as carbonate, bicarbonate and silicate can be present in the composition.

Description

LOW-DOSAGE AUTOMATIC DISHWASHING DETERGENT WITH MONOPERSULFATE AND ENZYMES

TECHNICAL FIELD The present invention is in the field of solid-form automatic dishwashing detergents. More specifically, the invention relates to nonphosphated (i.e., substantially free from inorganic phosphate builder salts) low-dosage forms of such compositions wherein there is present a beverage stain-removing amount of a monopersulfate salt. Granular and tabletted forms of the compositions are encompassed, as is a method of washing domestic tableware, such as dishes, glassware, cups and flatware, with the compositions here provided.

BACKGROUND OF THE INVENTION Automatic dishwashing detergents (ADD's) used for washing tableware in the home or institutionally in machines especially designed for the purpose have long been known. The particular requirements of cleansing tableware and leaving it in a sanitary, essentially spotless, residue-free state has indeed resulted in so many particular ADD compositions that the body of art pertaining thereto is now recognized as quite distinct from other cleansing product arts. British Patents 1,325,645; 1,527,706; and 1,381,187; European Patent Application EP-A 82,564; and U.S. Patents 4,427,417; 4,436,642; and 4,539,144 describe various aspects of ADD's, their components and their manufacture.

In recent times, there has been a renewed interest among consumers in effective, economical cleansing products, especially laundry detergents, using smaller amounts of chemicals and packaging for a diminished environmental impact. In light of legislation and current environmental trends, such products are desirably substantially free of inorganic phosphate builder salts. In addition, such compositions are desirably free of chlorine bleach and "inert" filler ingredients such as sodium sulfate.

Unfortunately, low-dosage nonphosphated ADD products may be made available to the consumer with a promise of effectiveness but in technical terms sacrificing efficacy, especially owing to the loss of phosphate and chlorine mainstay ingredients. Indeed, there does not currently appear to be a commercial low-dosage, nonphosphated ADD product which is economical and at the same time free from end-result shortcomings, such as relatively poor stain removal as compared with the same technology incorporated in regular-dosage nonphosphated formulas. Without being limited by theory, we believe stain removal shortcomings in particular are due to commercial perborate- and perborate-plus-activator ADD products relying quite heavily on a robust product matrix, which is lost in low-dosage product forms unless very expensive high levels of nonphosphorus builder are utilized.

In the course of exploratory studies to address this problem and secure improved low-dosage nophosphated compositions which are both economical and effective, it has been discovered that perborate, perborate-with-activator (such as tetraacetylethylene- dia ine) and others among the conventional oxygen bleach technologies are relatively intolerant of significant reductions in levels of alkaline ingredients, builders and "inert" fillers (which actually function as electrolytes), all seemingly vital to successfully arriving at low-dosage forms of the ADD products. Moreover, these shortcomings are especially apparent when the compact-form ADD is used under "stressed" conditions, such as is frequently the case in high-hardness areas or among economy-minded consumers who use products sparingly.

One way round the problem would be to use chlorine bleaches, meaning chlorine-containing compounds which release hypochlorite when dissolved in water; but chlorine bleach limits the formulator since it is incompatible with many desirable components of nonphosphated ADD's, such as enzymes and many nonphosphorus builders and surfactants. Accordingly, it is an object of the present invention to provide new and improved low-dosage ADD compositions. Such compositions are nonphosphated compositions, i.e., they are substantially free from, and unreliant on inorganic phosphate builders. The compositions herein are also free of chlorine bleach. More specifically, it is an object herein to provide low-dosage solid-form ADD's, especially granules, formulated with onopersulfate ("MPS") salts for highly effective removal of stains from tableware, especially beverage stains such as tea, tea with milk, or coffee, from cups and mugs. Dosages, that is to sa usage levels of ADD in automatic dishwashing appliances, ar generally from about 25%-70%, more typically from about 50 -60% o the dosage of a conventional phosphated, chlorine-bleach contain ing automatic dishwashing detergent. Another object herein is t provide a method for washing tableware in home or institutiona automatic dishwashing appliances, especially in home appliances using compositions provided herein at the specific dosage level further detailed hereinafter. The unique MPS-containing compositions herein provid numerous advantages in addition to compactness and stain-remova efficacy with economy. These include material protection via reduced tendency to etch glass and tableware, excellent spotless ness and lack of filming, high water solubility and elimination o undissolved product residue, and the ability to remove proteina ceous food residues from articles such as pots and pans.

BACKGROUND ART Monopersulfate salts, such as the potassium, sodium, an magnesium salts, as well as binary and ternary mixed salts o monopersulfate with alkali metal sulfates and/or bisulfates, ar generally known from the literature. One such salt, sold as 0X0N (registered trademark of DuPont), has been variously described i the literature as a mixture of potassium monopersulfate wit potassium sulfate and potassium bisulfate, or as a "triple salt having specific stoichiometry. The use of monopersulfate salt such as 0X0NE has previously been described. See: U.S. Patent 3,049,495; 3,556,711; 3,558,497; 3,732,170; 3,805,809; 3,819,828 3,945,937; 4,127,496; 5,041,232; 5,045,223; 5,047,163; Europea Patent Applications EP-A 135,226; EP-A 239,379; and EP-A 400,858 Japanese JP 58180420 A2; and South African ZA 8,301,869. Monoper sulfate salts are chemically different from peroxydisulfate salts such as potassium peroxydisulfate K₂S₂0₈. Indeed, peroxydisulfat alone is not effective in the instant invention.

SUMMARY OF THE INVENTION Compositions - The present invention encompasses low-dosag granular automatic dishwashing detergent compositions, in soli form, e.g., as granules or tablets, which are substantially fre of inorganic phosphate builders, substantially free of chlorin bleach, and preferably substantially free of inert fillers such as sodium sulfate, comprising:

(a) monopersulfate salt in an amount sufficient to provide from about 0.18% to about 1.3% by weight, more preferably from about 0.36% to about 1.1%, most preferably from about 0.54% to about 0.9% by weight of the composition of Available Oxygen (this corresponds to the amount of monopersulfate salt required to establish a usage level of Available Oxygen of from about 5 ppm to about 35 ppm, more preferably from about 10 ppm to about

30 ppm, most preferably from about 15 ppm to about 25 ppm);

(b) detersive enzyme in an amount sufficient to provide from about 0.01% to about 0.5%, more preferably from about 0.02% to about 0.2% of the composition, of active enzyme

(this corresponds to the amount of detersive enzyme required to establish a usage level of active enzyme of from about 0.5 ppm to about 5 ppm);

(c) from about 0.1% to about 10% by weight of the composi- tion of an organic dispersant; (this ingredient is typically a water-soluble or water-dispersible poly- electrolyte capable of inhibiting the precipitation of water hardness salts; such dispersants include the sodium polyacrylates, mono- and dicarboxy starches and the like);

(d) pH adjusting agent in an amount sufficient to establish a usage pH in the range from about 8 to about 11, preferably from about 9.5 to about 10.5, at typical composition usage levels of from about 1500 ppm to about 4000 ppm, more preferably from about 2000 ppm to about

3000 ppm, in water; (pH adjusting agent will typically comprise (i) from 0% to about 30%, more preferably from about 5% to about 25%, most preferably from about 8% to about 20% of the composition of a carbonate ingredient and (ii) from 0% to about 35%, more preferably from about 4% to about 25%, most preferably from about 6% to about 15% of a water-soluble silicate ingredient; always subject to the provision that the sum of the levels of pH-adjusting agent components (i) and (ii) is greate than zero. The carbonate ingredient is typicall selected from the group consisting of: sodium carbonate sodium bicarbonate, sodium sesquicarbonate, potassiu carbonate, potassium bicarbonate and potassiu sesquicarbonate and mixtures thereof; more preferabl this first component of the pH adjusting agent i selected from the group consisting of sodium carbonate sodium bicarbonate, sodium sesquicarbonate and mixture thereof. The water-soluble silicate ingredient i typically selected from the group consisting of hydrou sodium and potassium silicates having a Siθ2:M2θ rati in the range from about 1.6 to about 3, more preferabl from about 2 to about 2.4 wherein M represents sodium o potassium).

Preferred embodiments of the invention comprise composition having the above components (a) through (d) plus one or more o the following optional ingredients; in certain highly preferre embodiments of the invention, all of the optional ingredients ar present at non-zero levels:

(e) from 0% to about 1.5%, more preferably from about 0.1 to about 0.5% by weight of the composition of a chlorin bleach scavenger; (when present, the chlorine bleac scavenger is typically sodium perborate, preferably i the monohydrate form);

(f) from 0% to about 40%, more preferably from about 5% t about 30% by weight of the composition of a weak non phosphorus builder; (when present, this builder i preferably selected from organic carboxylate builder having molecular weight of below about 600; mor preferably the weak nonphosphorus builder is selecte from the group consisting of an alkali metal salt of on or more of: citrate, tartrate succinates, glycero succinates, carboxymethyloxysuccinate and glucohepton ate; most preferably this builder is sodium citrate i the trisodium, dihydrate form although citric acid ma be equally useful in the lower-pH embodiments); (g) from 0% to about 4% by weight of the composition, more preferably from about 0.1% to about 2%, most preferably from about 0.2% to about 0.7% by weight of the composi¬ tion, of a bleach stabilizer; (when present, the bleach stabilizer is preferably selected from the group con¬ sisting of organic nitrogen-containing sequestrants and organic phosphorus-containing sequestrants, more prefer¬ ably the bleach stabilizer is selected from the group consisting of organic nitrogen-containing sequestrants. Especially preferred nitrogen-containing sequestrants are ethylenediamine disuccinate, 1,2-oxoethanediyl- bis(aspartate) and diethylenetriaminepentacetate in acid or, more preferably, sodium-salt form); and (h) from about 0% to about 10% by weight, more preferably from about 1% to about 7%, most preferably from about 2% to about 5% of the composition of a low-sudsing surfact¬ ant. (When present, the low-sudsing surfactant is typically one known for use in ADD's and is selected from low-sudsing nonionic surfactants, low-sudsing anionic surfactants and their mixtures; and mixtures of higher-sudsing surfactants with a conventional suds- suppressor such as a silicone/silica mixture). Method - The invention also encompasses a method for cleaning dishware, and the like, comprising in an automatic dishwashing appliance containing domestic tableware, such as flatware, cups and mugs, glassware, dinner plates and/or pots and pans, a step of washing said tableware by contact with an aqueous bath comprising from about 1500 ppm to about 4000 ppm, more preferably from about 2000 ppm to about 3000 ppm, of the instant composition. Prefer- ably the appliance is a commercial domestic automatic dishwasher and there will be two such steps in sequence, with one or more rinse steps, in which no composition is dispensed, intervening between the said washing steps. Temperatures in the method can vary quite widely, but in accordance with normal practice, hot water preheated outside the appliance and having a temperature in the range from about 100^*F (37.8'C) to about 150^βF (65.6'C) may be used; alternatively, and depending on the power output of the heating coil which may be present in the appliance, cold water fill, such as at a temperature of from about 40"F (4.4^βC) to abo 80^βF (26.7'C), can be used and the water is heated in t appliance to temperatures of about 150^βF (65.6^βC), or higher. a preferred embodiment of the method, a washing step is follow by several rinse steps during which a conventional rinse agent m be dispensed to aid sheeting and drying action.

Units - All percentages, ratios and proportions herein are weight, unless otherwise noted. When percentages are quot without any particular indication as to whether the ADD composi tions, their aqueous solutions at usage level, or percentages components such as water in raw materials are intended, su percentages should be taken to refer to percentages by weight the fully-formulated automatic dishwashing detergent. The abbr viation "ppm" refers to "parts by million". When "ppm" is us without indicating whether the ADD compositions or their aqueo solutions are intended, "ppm" should be taken to refer to usag level parts by million of the indicated ingredient or compositi ^' in wash water.

DETAILED DESCRIPTION OF THE INVENTION

The present invention employs ingredients which are generall known in the art, but which are combined in a unique manner herei to provide important cleaning benefits in an automatic dishwashi detergent context. More specifically, the combination of t ingredients in the manner disclosed hereinafter allows the formul tion of what might be referred to as "low dosage" or "compact automatic dishwashing detergent compositions which are characte ized by the fact that they contain lesser volumes of ingredient than conventional, granular dishwashing detergents now being sol yet perform well under a wide variety of conditions. These lesse volumes are achieved without it being essential to resort t densification. ("Densification" or "densified", as distinct fro "compaction" or "compact" as used herein, refers to a proces involving physically compressing the product by the application pressure). Since excessive densification tends to adversel affect ADD solubility and since solubility of ADD's is prized the consumer owing to the avoidance of undissolved detergen residues, the invention brings with it solubility advantages Densities of typical compositions herein are in the range fro about 0.7 g/cm³ to about 1.2 g/cm³, more preferably from about 0.8 g/cm³ to about 1.1 g/cm³. In light of the reduced volume and excellent solubility, the consumer is afforded more convenient compositions which, as used in properly functioning automatic dishwashing appliances, do not leave unsightly residues of undissolved detergent.

The compositions herein are formulated to be substantially free of inorganic phosphate salts (phosphate builders) and are substantially free of chlorine bleaches. While it may be thought that the selection of non-chlorine bleaches for use in compositions of the present type is a routine affair, the selection of monopersulfate salts (sometimes known as monoperoxysulfate salts) from among the many known oxygen bleaches (e.g., perborate, percarbonate, peroxydisulfate, organic peracids, perborate-with-activator and the like) takes into consideration various factors designed to provide optimum cleaning performance in the present compositions. Without being bound by theory, optimum stain removal performance by low-dosage ADD's in the absence of conventional chlorine bleaches requires an oxygen bleaching species to be present throughout the washing operation. In a low-dosage ADD composition, this bleach at usage levels of only a few ppm to a few tens of ppm Available Oxygen in the wash water must operate at much lower electrolyte, hydroxide ion/pH adjusting agent and builder levels, as compared with the levels afforded by conventional dosage ADD's. It is now surprisingly revealed that of the known oxygen bleaches, monopersulfate salts do exceptionally well in this regard. Moreover high wash water temperatures or dispersed soils from the tableware can rapidly consume Available Oxygen, thereby preventing bleach from reaching and acting on the stained tableware. Again, it transpires that monopersulfate is effective for stain-removal in low-dosage ADD's while at the same time being relatively resistant to such causes of wasteful decomposition when formulated and used in accordance with the invention. In particular circumstances known as "stressed usage conditions", referring to high domestic water hardness, sparing^' use of ADD, excessively high or low wash temperatures and the like, monopersulfate salts as formulated herein are believed to provide superior stain removal results a compared with other conventional oxygen bleaches otherwis similarly formulated.

Monopersulfate Salts - Monopersulfate salts (MPS bleach employed herein comprise compounds which dissociate in water t provide monopersulfate species such as HSO5" or the correspondin dianion or radical anions. Such salts are illustrated by potas sium monopersulfate, sodium monopersulfate, magnesium monopersul fate, and tetra-alkylammonium onopersulfates such as tetrabutyl ammonium monopersulfate. A long-known and readily commerciall available monopersulfate salt employed herein is a "triple salt" Comm ercial compositions comprising this salt are available unde the tradename OXONE, from DuPont. OXONE has the Chemical Abstract Registry Number 37222-66-5 and is in the form of a stable, free flowing powder which comprises 2KHS0₅.K₂S0 .KHS0₄. Since thi salt is the most readily available, it is used in many preferre embodiments of this invention. The lower molecular weight (an thus more mass-efficient) MPS salts are desirably used for low dosage ADD compositions of the invention, but these salts are no commonly available in bulk, and must be made by conventiona literature methods. Chemical practitioners will of course b aware that cations accompanying the monopersulfate can conveni ently be exchanged by metathesis. Yet another approach is to shi bulk liquid stock of a solution of sodium or potassium monopersul fate, and, subject to the normal safety procedures for oxidants o this general type, dry or otherwise convert it adjacent the AD manufacturing facility to whatsoever convenient solid form i desired.

Available Oxygen - "Available Oxygen" as defined herei refers to percentage by weight of titratable 0 (not 0₂), inclusiv only of titratable 0 from monopersulfate salts and specificall exclusive of titratable 0 from any active oxygen-containin chlorine bleach scavenger which may be used. Titration may b done using any convenient literature method for the determinatio of MPS bleaches, such as iodometric methods. See, for example Skoog and West, Fundamentals of Analytical Chemistry, Holt Rinehart, 1976, pages 362-369 and 748-751. Conversion between Available Oxygen (AvO) and percentage of monopersulfate salt in any given composition is illustrated in the case of the pure monopersulfate triple salt 2KHS0₅'KHS0₄'K₂S0₄ as fol1ows: triple salt molecular weight = 614.74 g/mol ; mass fraction of Active Oxygen in pure triple salt = 32/614.74; where 32 corresponds with two moles of Available 0 per mole of the triple salt in accordance with the presence of two moles of potassium monopersulfate in the triple salt formula; percentage of Available Oxygen in the pure triple salt = (32/614.74)*100 = 5.21% AvO.

Let us say, for example, that a given ADD composition in accordance with the invention has a percentage of Available Oxygen of 0.78% Then the percentage by weight of monopersulfate triple salt that it contains, assuming the salt is pure, is given by: 0.78/0.0521 = 14.97%

Similar conversions apply to any other composition in accord¬ ance with the invention, requiring only that the appropriate molecular weight of the monopersulfate salt be used. It will naturally be appreciated that commercial-grade monopersulfate salts can be used, such as OXONE triple salt formulated with commercial stabilizers and the like, in which case conversion from analyzed % AvO to percentage by weight of commercial-grade OXONE in the composition will include an assay factor. It has been found that commercial OXONE typically contains only about 88 percent by weight of the pure triple salt, accordingly a percent¬ age by weight of the commercial sample will be increased by the assay factor: taking the above-given illustration, if the analyzed Available Oxygen in the composition was 0.78%, the content of 88% commercial OXONE would be:

(0.78/0.0521)*l/0.88 = 17.01% where 0.88 is the assay factor.

For simplicity, OXONE percentages other than in the detailed Examples are given on a pure basis herein, unless otherwise specifically indicated. Typically, the compositions herein will comprise from about 1% to about 9.5% by weight of MPS (as HSO_s ^_), which translates into about 3% to about 25% by weight OXONE, dry basis as the pure triple salt. Detersive Enzyme - The enzymes employed in the presen compositions are of types well-known in the art. Such enzymes ar commonly available in "prill" form. A prill is a fabricate particle containing varying proportions of active enzyme, inactiv enzyme, and supporting materials which serve to stabilize th active enzyme during storage. For this reason, the levels o enzyme in the instant compositions are specified on the basis o active enzyme content. Assays may be carried out using any of th standard methods available from the enzyme suppliers. It i essentially immaterial to know the precise nature and level of th inactive components of the prill, except that it has bee discovered that overly high levels of inactive enzyme and pril ingredients, e.g., above about 8% by weight of the fully formulated ADD composition, actually tend to have adverse effect on the filming characteristics of the ADD; such levels shoul preferably be avoided.

Suitable enzymes herein comprise proteolytic enzymes well known in the art. Proteolytic enzymes such as SAVINASE, ESPERAS and ALCALASE, sold by NOVO Industries, Copenhagen, Denmark, ar particularly useful herein, since proteolytic enzymes serve t attack, degrade and remove various protein residues from th tableware being cleaned. Moreover, it has been discovered that i combination with oxygen bleach, such proteolytic enzymes, or thei variants engineered for greater oxygen bleach stability, wor exceptionally well for the removal of tea-with-milk stains fro cups and mugs.

Amylase enzymes can also be used, either in combination wit proteases in an optional, but preferred mode, or singly, in th compositions of the invention. Amylase sold by NOVO under th name TERMAMYL is a typical example.

Enzyme activity and enzyme activity measurement are describe in detail in the following publications, incorporated herein b reference: "Enzyme Nomenclature Recommendations (1972) of th International Union of Pure and Applied Chemistry and th International Union of Biochemistry", 2nd Reprint, 1975, ISB 0-444-41139-9 and Publications B259c (Alcalase), B260c (Esperase and B274c (Terma yl), all published March 1988 by Novo Industri A/S, Novo Allέ, 2880 Bagsvaerd, Denmark. Organic Dispersant - As noted hereinabove, the present compositions contain organic dispersant which overcomes the problem of unsightly films which form on china and especially on glassware due to calcium- or magnesium-hardness-induced precipita- tion of pH-adjusting agents, especially carbonates, used herein.

The organic dispersants herein are used at levels of at least about 0.1%, typically from about 1% to about 10%, most preferably from about 1% to about 7% of the automatic dishwashing composi¬ tion. Such organic dispersants are preferably water-soluble sodium polycarboxylates. ("Polycarboxylate" dispersants herein generally contain truly polymeric numbers of carboxylate groups, e.g., 8 or more, as distinct from carboxylate builders, sometimes called "polycarboxylates" in the art when, in fact, they have relatively low numbers of carboxylate groups such as four per molecule.) The organic dispersants are known for their ability to disperse or suspend calcium and magnesium "hardness", e.g., carbonate salts. Crystal growth inhibition, e.g., of Ca/Mg carbonates, is another useful function of such materials. Prefer¬ ably, such organic dispersants are polyacrylates or acrylate- containing copolymers. "Polymeric Dispersing Agents, SOKALAN", a printed publication of BASF Aktiengesellschaft, D-6700 Ludwigshaven, Germany, describes organic dispersants useful herein. Sodium polyacrylate having a nominal molecular weight of about 4500, obtainable from Rohm & Haas under the tradename as ACUS0L 445N, or acrylate/maleate copolymers such as are available under the tradename SOKALAN, from BASF Corp., are preferred dispersants herein. These polyanionic materials are, as noted, usually available as viscous aqueous solutions, often having dispersant concentrations of about 30-50%. The organic dispersant is most commonly fully neutralized; e.g., as the sodium salt form.

While the foregoing encompasses preferred organic dispersants for use herein, it will be appreciated that other oligomers and polymers of the general polycarboxylate type can be used, according to the desires of the formulator. Suitable polymers are generally at least partially neutralized in the form of their alkali metal, ammonium or other conventional cation salts. The alkali metal, especially sodium salts, are most preferred. While the molecular weight of such dispersants can vary over a wide range, it preferably is from about 1,000 to about 500,000, mo preferably is from about 2,000 to about 250,000, and mos preferably is from about 3,000 to about 100,000. Nonlimitin examples of such materials are as follows. For example, other suitable organic dispersants include thos disclosed in U.S. Patent 3,308,067 issued March 7, 1967, to Diehl incorporated herein by reference. Unsaturated monomeric acid that can be polymerized to form suitable polymeric polycarboxyl ates include maleic acid (or maleic anhydride), fumaric acid itaconic acid, aconitic acid, mesaconic acid, citraconic acid an methylenemalonic acid. The presence of monomeric segments con taining no carboxylate radicals such as vinylmethyl ether styrene, ethylene, etc. is suitable, preferably when such segment do not constitute more than about 40% by weight of the polymer. Other suitable organic dispersants for use herein are copoly mers of acrylamide and acrylate having a molecular weight of fro about 3,000 to about 100,000, preferably from about 4,000 to abou 20,000, and an acrylamide content of less than about 50%, prefer ably less than about 20%, by weight of the polymer. Most prefer ably, the polymer has a molecular weight of from about 4,000 t about 10,000 and an acrylamide content of from about 1% to abou 15%, by weight of the polymer.

Still other useful organic dispersants include acrylate/male ate or acrylate/fumarate copolymers with an average molecula weight in acid form of from about 2,000 to about 80,000 and ratio of acrylate to maleate or fu arate segments of from abou 30:1 to about 2:1. Other such suitable copolymers based on mixture of unsaturated mono- and dicarboxylate monomers ar disclosed in European Patent Application No. 66,915, publishe December 15, 1982, incorporated herein by reference. Yet othe organic dispersants are useful herein, as illustrated by water soluble oxidized carbohydrates, e.g., oxidized starches prepare by art-disclosed methods.

With regard to the formulations herein, it is preferred tha the ratio of organic dispersant to Available Oxygen from monoper sulfate salts is in the range from about 0.5:1 to about 8:1 preferably from about 0.5:1, to about 5:1, by weight. pH-Ad.iusting Agent - The compositions herein also contain at least one source of alkalinity so as to achieve an in-use pH above 7. It will be appreciated by those familiar with compositions for use in the home that accidental ingestion of high alkalinity products can pose safety concerns. Moreover, such concerns would be increased in the case of highly alkaline, low-dosage composi¬ tions. While the invention is effective at a pH in the highly alkaline range, it is an advantage herein not to be limited to compositions with such alkalinity levels. Wash pH's suitable for effective stain removal in the prac¬ tice of this invention are generally in the range from about 8 to about 11, more preferably from about to about 9.5 to about 10.5 when water-soluble silicates are present though the invention encompasses other preferred embodiments in which the pH range is from about 8 to about 9.5, from which water-soluble silicates are absent and wherein the pH-adjusting function is performed only by the carbonate ingredient which can take the form of sodium bicar¬ bonate or a sodium carbonate/bicarbonate mixture. To be noted, the perborate-type bleach systems are ineffective at the most desirable low end of these ranges, especially in the low-dosed product form provided herein. The water-soluble carbonate salts, especially sodium carbonate and bicarbonate, are useful alkalinity sources herein, and when present are typically used at levels from about 5% to about 25%, preferably from about 8% to about 20% by weight of the final granular product. It will be appreciated by those familiar with ADD compositions that excessive amounts of carbonate can result in undesirable filming on cleansed tableware. However, the tendency to filming is offset by use of organic dispersant materials disclosed hereinabove. Importantly, material care benefits are best imparted to the instant compositions either when they are formulated at the moderate pH's (8-9.5) without soluble silicates (in which case sodium bicarbonate, sodium carbonate or a mixture of the two will be used for the pH-adjusting function), or when they are formu- lated at the somewhat higher (9.5-10.5) pH range when a mixture of water-soluble silicate and sodium carbonate is typically used as pH-adjusting agent. When the compositions herein contain water-soluble silicat as a component of the pH-adjusting agent, these silicates not onl provide alkalinity to the compositions, but also provide anti corrosion benefits for aluminum utensils and appear to contribut to glaze protection on chinaware.

Since the compositions herein are formulated to contai limited amounts of free water for best storage stability, bu since on the other hand complete dehydration of silicates tends t limit water-solubility of the compositions, it is important tha the water-soluble silicates processed into the formulation ultimately have solid hydrous form. This can be achieved either b admixing into the composition preformed solid hydrous silicates a the water-soluble silicate component, or by relying on a mor inexpensive liquid silicate stock, which is dehydrated to limited extent during granule-making.

When water-soluble silicates are used in the practice of th invention, their level in the fully-formulated composition i preferred embodiments is in the range from about 4% to about 25%, more preferably from about 6% to about 15%, dry basis, based o the weight of the automatic dishwashing detergent composition. The mole ratio of Siθ2 to the alkali metal oxide (M₂0, where M i alkali metal) is typically from about 1 to about 3.2, preferabl from about 1.6 to about 3, more preferably from about 2 to abou 2.4. Preferable H₂0 levels in commercial raw material forms o the water-soluble silicate component itself are from about 15% t about 25%, more preferably, from about 17% to about 20% of th water-soluble silicate component.

The highly alkaline etasilicates can be employed, althoug the less alkaline hydrous alkali metal silicates having a Si0₂:M₂ ratio of from about 2.0 to about 2.4 are preferred.

Sodium and potassium, and especially sodium silicates ar preferred. Particularly preferred alkali metal silicates ar granular hydrous sodium silicates having Si0 :Na₂0 ratios of fro 2.0 to 2.4 available from PQ Corporation, named BRITESIL H20 an BRITESIL H24. Most preferred is granular or powder-form hydrou sodium silicate having a Si0₂:Na₂0 ratio of about 2.0. Potassiu analogs could be employed, but are generally more expensive. While typical forms, i.e., powder and granular, of hydrous silicate particles are suitable, preferred silicate particles have a mean particle size between about 300 and about 900 microns with less than 40% smaller than 150 microns and less than 5% larger than 1700 microns. Particularly preferred is a silicate particle with a mean particle size between about 400 and about 700 microns with less than 20% smaller than 150 microns and less than 1% larger than 1700 microns.

Chlorine Bleach Scavenger - As noted hereinabove the preferred compositions herein contain detersive enzymes. It has been determined that chlorine bleach species present in many water supplies can attack and inactivate such enzymes, especially under alkaline conditions. While chlorine levels in water may be small, typically in the range from about 0.5 ppm to about 1.75 ppm Available Chlorine, the total volume of water that comes in contact with the enzyme during dishwashing is usually large; accordingly, enzyme stability in-use can be problematic. Unlike the more conventional Oxygen bleach perborate, the monopersulfate bleach herein is not of its own accord a chlorine bleach scaven- ger. However, it has now been determined that scavenger materials such as sodium perborate can be used in the compositions as a chlorine scavenger. Accordingly, preferred compositions herein will contain up to about 1.5%, preferably from about 0.1% to about 0.5%, by weight of a chlorine bleach scavenger, such as a water- soluble perborate salt. Either sodium perborate tetrahydrate or sodium perborate monohydrate can be used for this chlorine scav¬ enging purpose. Alternatively, boron-free scavengers may be used, in which case somewhat larger quantities may be useful. Preferred boron-free scavengers include percarbonate salts, malate salts, tartrate, ammonium sulfate and lower al anolamines.

Weak Nonphosphorus Builder - The compositions herein may also contain a nonphosphorus detergency builder. It has been found that weak builders, especially organic carboxylate builders having a molecular weight below about 600, are especially useful to allow an effective composition which does not etch glass or chinaware. Normally, the for ulators of detergent compositions attempt to employ high levels of the strongest possible builder in their formulations and indeed, when Oxygen bleaches such as perborate or perborate with activator are used, stronger builders are neede for the most satisfactory stain removal results. However, i conjunction with monopersulfate salts, the balance of the composi tions herein provides adequate cleaning benefits even when zero t relatively low amounts of weak builders are used and this permit a substantial safety advantage with regard to the protection o the glaze on fine china and the strength and clarity of glassware Citrate builders, particularly sodium citrate, are preferred fo use herein, rlucoheptonate builders known in the art are likewis useful. Sucn builders, especially sodium citrate or citric acid are preferably used at levels from about 2% to about 15% b weight, more preferably about 3% to about 8% by weight of th present compositions.

Bleach Stabilizer - The compositions herein will preferabl also contain a bleach stabilizer whose primary purpose is t sequester transition metal ions that can decompose monopersulfat bleach. Such bleach stabilizers generally are selected fro organic nitrogen-containing sequestrants and organic phosphorus containing sequestrants and are thus distinguished from the wea builders herein which do not contain nitrogen or phosphorus Conveniently, bleach stabilizers can be blended with commercia monopersulfate in granular form, e.g., in OXONE granules. It ma also be advantageous to have low levels of bleach stabilize dispersed throughout the composition. In this mode, it is believe that the bleach stabilizer is principally active as a storage stabilizer for the bleach. Otherwise, bleach stabilizers such a the common chelant diethylenetriaminepentaacetate can be added t the compositions to provide the desired stabilizing function.

In more detail, the bleach stabilizer in the fully-formulate granular automatic dishwashing detergent compositions herein ca be used at levels ranging from the minimum amount required fo bleach stabilizing purposes (e.g., as low as about 0.05% to 0.1% to much higher levels (e.g., about 0.5% or higher) which are ver useful levels not only for best achieving the instant process, bu also for achieving enhanced functionality of the automatic dish washing detergent (e.g., food/beverage stain removal from dishes transition metal oxide film control or removal, and the like. When bleach stabilizer is present, more typical levels are thu from about 0.05% to about 2% or higher, preferably from about 0.1% to about 0.7%, all percentages on a weight basis of the final automatic dishwashing composition.

Bleach stabilizers suitable for use herein of the organic nitrogen-containing type are further illustrated by the sodium and potassium salts of ethylenediaminetetraacetic acid (EDTA), diethylenetriamine pentaacetic acid (DTPA), hydroxyethylenediamine triacetic acid (HEDTA), triethylenetetra ine hexaacetic acid (TTHA), nitrilotriacetic acid (NTA), N,N'-(l-oxo-l,2,-ethanediyl)- bis(aspartic acid) (0EDBA), and ethylenediamine disuccinic acid (EDDS); see U.S. 4,704,233.

Bleach stabilizers of the organic phosphorus containing type are further illustrated by ethylenediaminetetra-(methylenephos- phonic acid), diethylenetriaminepenta(methylene phosphonic acid) and hydroxy-ethylidine-diphosphonic acid (EHDP). Certain of these materials have been found to behave somehat unpredictably, it is believed due to variations in quality of raw material. Therefore, such organic phosphorus-containing sequestrants are not as highly preferred as the nitrogen types for use in the present invention.

Highly preferred bleach stabilizers are the nonphosphorus chelants, such as EDDS and 0EDBA. These are believed to have attractive characteristics from the viewpoint of the environment; for example, EDDS has two chiral centers and not only synthetic or mixed isomers, but also the natural isomers such as the [S,S] iso er can be used compatibly with this invention.

Of the foregoing bleach stabilizers, all but OEDBA deriva¬ tives are well-known in the art. OEDBA is disclosed by Glogowski et al in U.S. Patent 4,983,315, issued January 8, 1991, incorpor¬ ated herein by reference. A document generally useful in the context of this invention for its disclosure of commercial chemicals, including but not limited to chelants, their trademark names and commercial sources of supply, is "Chem Cyclopedia 91, The Manual of Commercially Available Chemicals", a publication of the American Chemical Society, 1990, ISBN 08412 - 1877-3, incorporated herein by reference. Although, the sodium and potassium, i.e., alkali metal salt of the bleach stabilizers are preferred, they can, in general, b in the acid form or can be partly or fully neutralized, e.g., a the sodium salt. Low-Sudsing Surfactant - The compositions herein may contai from 0% to about 10%, preferably from about 1% to about 7% b weight of a surfactant, preferably a low sudsing surfactant of th type typically used in conventional ADD compositions known i commerce. Such surfactants not only provide some cleaning actio in the compositions, but also provide a "sheeting" action whic causes water to drain from china and glassware, thereby reducin the tendency to form unsightly spots during drying in the auto matic dishwashing machine. Typically, such low sudsing surfact ants fall within the class known as nonionics, especially th so-called "block" polyoxyethylene-polyoxypropylene nonionics, bu various other low-sudsing surfactants such as the long-chai phosphates and phosphate esters can also be used. The followin is intended to further assist the formulator in the selection o surfactants for use herein, but is not by way of limitation. The surfactant can be, for example, an ethoxylated surfactan derived from the reaction of a monohydroxy alcohol or alkylphenol containing from about 8 to about 20 carbon atoms, excluding cycli carbon atoms if such are present, with from about 4 to about 1 moles of ethylene oxide per mole of alcohol or alkyl phenol on a average basis. A particularly preferred ethoxylated nonioni surfactant is derived from a straight chain fatty alcohol contain¬ ing from about 16 to about 20 carbon atoms (C6-C20) alcohol), preferably a C18 alcohol, condensed with an average of from abou 6 to about 15 moles, preferably from about 7 to about 12 moles, and most preferably from about 7 to about 9 moles of ethylen oxide per mole of alcohol. Preferably the ethoxylated nonionic surfactant so derived has a narrow ethoxylate distribution rela¬ tive to the average. The ethoxylated nonionic surfactant can als optionally contain propylene oxide in an amount up to about 15% b weight of the surfactant.

. Another type of nonionic surfactant contains the ethoxylated monohydroxyalcohol or alkyl phenol and additionally comprises polyoxyethylene-polyoxypropylene block polymeric compound; th ethoxylated monohydroxy alcohol or alkyl phenol nonionic surfact¬ ant comprising from about 20% to about 80%, preferably from about 30% to about 70%, of the total surfactant composition by weight. Suitable block polyoxyethylene-polyoxypropylene polymeric compounds include those based on ethylene glycol, propylene glycol, glycerol, trimethylolpropane and ethylenediamine as an initiator reactive hydrogen compound. Polymeric compounds made from a sequential ethoxylation and propoxylation of initiator compounds with a single reactive hydrogen atom, such as C12-C28 aliphatic alcohols, do not usually provide satisfactory suds control. Certain of the block polymer surfactant compounds designated PLUR0NIC, PLURAFAC and TETR0NIC by the BASF-Wyandotte Corp., Wyandotte, Michigan are suitable as the surfactant for use herein. A particularly preferred embodiment contains from about 40% to about 70% of a polyoxypropylene, polyoxyethylene block polymer blend comprising about 75%, by weight of the blend, of a reverse block co-polymer of polyoxyethylene and polyoxypropylene containing 17 moles of ethylene oxide and 44 moles of propylene oxide; and about 25%, by weight of the blend, of a block co-polymer of polyoxyethylene and polyoxypropylene, initiated with tri-methylol propane, containing 99 moles of propylene oxide and 24 mol.es of ethylene oxide per mole of trimethylol propane.

Additional surfactants useful herein include relatively low-molecular weight nonionic types having melting-points at or above ambient temperatures, such as octyldimethylamine N-oxide dihydrate, decyldimethylamine N-oxide dihydrate, C8-C12 N-methyl- glucamides and the like. Such surfactants may advantageously be blended in the instant compositions with short-chain anionic surfactants, such as sodium octyl sulfate and similar alkyl sulfates, though short-chain sulfonates such as sodium cumene sulfonate could also be used. Short-chain nonionic types which tend to be liquid or melt close to ambient temperatures may be incorporated into the instant compositions by wicking them into an inorganic support, such as preformed granule comprising porous carbonate particles. Thus nonionics derived from monohydric alkanols with ethylene oxide, such as C10E3 through C10E8, where "E" refers to ethylene oxide, may be used in the instant compositions. When sudsing tendencies of the compositions in-use a adversely affected by the use of surfactants with foami tendencies, limited amounts of conventional suds suppressors su as silicone/silica mixtures, may be incorporated into t surfactant system of the instant compositions as taught in t literature.

Filler/Electrolyte - The MPS-containing compositions herei are formulated in "compact" form and are reliant on electroly level for stain removal to a lesser degree than otherwise simil compositions made using perborate or perborate/tetraacetylethyl enedia ine. Thus, the instant compositions can be made substa tially free from, i.e., can be made with less than about 5%, a preferably contain 0%, of so-called "inert" ingredients such sodium sulfate. Nonetheless, such filler ingredients may be us if desired provided that the detergent remains compact, within t spirit and scope of the invention.

Other O^ptional Ad^juncts - Optional adjuncts useful in th practice of this invention include perfumes, borax and sodium o potassium borates, pH 7-9 organic buffers and any compounds in th published patent and journal literature known to accelerate o enhance the bleaching action of monopersulfate salts. A non limiting example of such MPS-accelerator materials is the grou consisting of keto-compounds, including sodium acetate an di-2-pyridyl ketone, the latter being more effective by virtue o the electronic effect of the substituents. Activation of monoper sulfate is, of course, not limited to ketones in light of variety of compounds having C=N and C=S bonds. To be noted however, is that an advantage of the instant invention is it simplicity and lack of reliance on any such MPS-activating com pound as an essential component. It has been found in the case o activated perborate-containing ADD's that the activator, whil helping bleaching and stain removal under the controlled condi tions of technical test laboratories is capable of producin erratic performance in the home on account of segregation as wel on account of the tendency of the highly reactive product o activation (peracetic acid) to decompose wastefully on heating o upon encountering dispersed food soils. Water Content - The water content of the compositions herein should be kept to a level below about 9% by weight of free moisture. This is due in part to the desirability of having free-flowing granules, and is particularly important when using OXONE as the monopersulfate salt. This monopersulfate salt is acidic and, in the presence of water, may react with carbonate or bicarbonate unless the limits on water content of the composition are respected or an expensive protective coating is applied. It is to be understood, however, that water can be used during the formation of the compositions herein. Thus, other than the monopersulfate, the balance of the compositions herein can be prepared as mixtures in an aqueous slurry and dried in standard fashion to provide substantially dry granules. Particles of dry monopersulfate can then be dry-blended with the aforesaid, dried balance of the composition.

The following examples illustrate compositions which come within the scope of this invention, but are not intended to be limiting thereof. In general, the compositions are prepared using the following general processing methodology. Process - Although the art includes processes which rely on dry-mixing or spray-drying ingredients, such processes are not of the general kind of interest herein as they generally produce products with low density or high tendency to segregate in the package. Thus for the present purposes, conventional automatic dishwashing compositions can typically be made by a process comprising two essential stages: mixing/drying wet-and-dry ingredients, optionally including molten-form surfactants, to form particles having granulometry generally appropriate for the intended use; and mixing free-flowing, relatively dry components, of compatible granulometry, with the product of the first stage. The latter mixing stage is, of course, necessary since bleach- active salts such as monopersulfate and enzyme prills are not tolerant of the wet-stage processing.

As compared with the known processes for making granular automatic dishwashing detergents with oxygen bleach, preferred embodiments of this invention typically will comprise: (a) in the presence of water, forming a fluid premix consisting essentially of an organic dispersant and a bleach stabilizer; (b) one or more mixing/drying steps wherein the fluid premix is contacted wit solid-form water-soluble nonphosphorus salts, very preferably, b means of conventional agglomeration and fluidized-bed dryin equipment, sequentially; and (c) addition of bleach-active salts Optionally, additional spray-ons or additions of other component sucn as perfumes, and the like, can be performed. Particularl <^■ .irable options which can be accommodated are illustrated by (i inclusion of perfume in the step (a) premix; (ii) inclusion o fluid-form surfactant in step (b) and (iii) inclusion of hydrou silicates in step (c). Other optional adjuncts can also, i general, be added in steps (a), (b) or (c). Minors, e.g., perfum and colorants, typically comprise less than about 3% of th finished formula.

EXAMPLE I An ADD composition whose compactness is 60% that of conven tional ADD compositions (i.e., 40% reduction in usage levels) i as follows. The composition is designed for use at about 23.4 per wash cycle (3,600 ppm in wash water). Ingredient % fwt.) Trisodium citrate¹ 13

Sodium carbonate (anhydrous basis) 17

Silicate (2.0 ratio)² 18

Nonionic surfactant³ 4.3

Sodium polyacrylate (m.w. 4,000)* 5.0 DTPA⁵ 0.83

OXONE (% Av 0)⁶ 15 (0.69)

TERMAMYL 60 T prill⁷ 2.78

SAVINASE 6.0 T pril 1.67

Na₂S0₄/H₂0/minors⁹ Balance trisodium citrate dihydrate, expressed on anhydrous basis. ²BRITESIL H20, PQ Corp., expressed on anhydrous basis. ³C₁₈E₇.g blend with reverse PO-EO-PO block copoly er an onostearyl acid phosphate at a weight ratio of about 39:60:1. «ACCUS0L, Rohm & Haas. ⁵Diethylenetriamine pentaacetate, pentasodium salt, anhydrou basis.

⁶The first number quoted being percentage of commercial-grad OXONE in the composition. ⁷Approxi ate prill content of active enzyme = 2.5%, dry basis. approximate prill content of active enzyme = 1.5%, dry basis. ^sMaxi_ιum 8% wt. H₂0 in composition.

EXAMPLE II An ADD composition whose compactness is 50% that of conven¬ tional ADD compositions (i.e., 50% reduction in usage levels) is as follows. The composition is designed for use at about 19.5 g per wash cycle (3,000 ppm in wash water).

Ingredient % (wt.)

Trisodium citrate¹ 15

Sodium carbonate (anhydrous basis) 20

Silicate (2.0 ratio)² 21.4 Nonionic surfactant³ 3.5

Sodium polyacrylate (m.w. 4,000)⁴ 5.3

DTPA⁵ 2.44 OXONE (% Av 0) 20.7 (0.95)

TERMAMYL 60 T prill 1.1 SAVINASE 6.0 T prill 3.0

H₂0/minors⁶ Balance ^xTrisodium citrate dihydrate, expressed on anhydrous basis. ²BRITESIL H20, PQ Corp., expressed on anhydrous basis. ³C₁₈E₇.₉ blend with block copolymer, as in Example I. *ACCUS0L, Rohm & Haas.

⁵Diethylenetriamine pentaacetate, pentasodiu salt, anhydrous basis.

⁶Maximum 8.5% wt. H₂0 in composition.

EXAMPLE III An ADD composition whose compactness is 50% that of conventional ADD compositions (i.e., 50% reduction in usage levels) is as follows. The composition is designed for use at about 19.5 g per wash cycle (3,000 ppm in wash water). Ingredient % (wt.) Trisodium citrate¹ 10

Sodium carbonate 20

Silicate (2.0 ratio)² 21 Nonionic surfactant³ 3.5

Sodium polyacrylate (m.w. 4,000)⁴ 5.3

DTPA⁵ 2.44

OXONE (% Av 0) 15 (0.69) SAVINASE 6.0 T prill 1.6

Na₂S0₄/H₂0/minors⁶ Balance trisodium citrate dihydrate, expressed on anhydrous basis. ²BRITESIL H20, PQ Corp., expressed on anhydrous basis.

⁴ACCUS0L, Rohm & Haas.

⁵Diethylenetriamine pentaacetate, pentasodiu salt. ⁶Maximum 7.5% wt. H₂0 in composition.

EXAMPLE IV An ADD composition whose compactness is 50% that of conven tional ADD compositions (i.e., 50% reduction in usage levels) i as follows. The composition is designed for use at about 19.5 per wash cycle (3,000 ppm in wash water). (This composition i less preferred owing to the relatively high level of expensiv sodium citrate employed.) Ingredient % (wt.)

Trisodium citrate¹ 39

Silicate (2.0 ratio Si0₂:Na₂0)² 28.6

Nonionic surfactant³ 1.4

Organic dispersant⁴ 5.7 0X0NE (% Av 0) 20.7 (0.95)

TERMAMYL 60 T prill 2.4

SAVINASE 6.0 T prill 1.8

Na₂S0₄/H₂0/minors⁵ Balance ^xTrisodium citrate dihydrate, expressed on anhydrous basis. ²BRITESIL H20, PQ Corp., expressed on anhydrous basis.

⁴ACCUS0L, Rohm & Haas; sodium polyacrylate, m.w. 4,000. ⁵Maximum 6.5% wt. H₂0 in composition.

EXAMPLE V An ADD composition whose compactness is 50% that of conven tional ADD compositions (i.e., 50% reduction in usage levels) i as follows. The composition is designed for use at about 19.5 per wash cycle (3,000 ppm in wash water). Ingredient % (wt.)

Trisodium citrate¹ 24.0

Sodium carbonate 12.5

Silicate (2.0 ratio)² 27.5 Nonionic surfactant³ 1.5

Organic dispersant⁴ 6.0

OXONE (% Av 0) 15.5 (0.7)

TERMAMYL 60 T prill 0.8

SAVINASE 6 T prill 2.2 Na₂S0₄ 10.0

H₂0/minors⁵ Balance ^xTrisodium citrate dihydrate, as supplied. ²BRITESIL H20, PQ Corp., as supplied. ³PLURAFAC LF 404, BASF Corp. ^~Acrylate:maleate copolymer, sodium salt, m.w. 65,000, dry basis.

⁵Maximum 9% wt. H₂0 in composition.

(This composition, in use, typically delivers 0.29 ppm active enzyme TERMAMYL and 1.4 ppm active enzyme SAVINASE when 4,000 ppm product is dissolved in water.)

EXAMPLE VI An ADD composition whose compactness is 60% that of conventional ADD compositions (i.e., 40% reduction in usage levels) is as follows. The composition is designed for use at about 23.4 g per wash cycle (3,600 ppm in wash water). Ingredient % (wt.)

Trisodium citrate¹ 20.0

Sodium bicarbonate 20.0

Nonionic surfactant² 5.0 Organic dispersant³ 4.0

DTPA⁴ 2.44

OXONE (% Av 0) 15.0 (0.69)

TERMAMYL 60 T prill 1.1

SAVINASE 6.0 T prill 2.0 Na₂S0₄/H₂0/minors⁵ Balance

¹Trisodium citrate dihydrate, expressed on anhydrous basis.

²PLURAFAC LF 404, BASF Corp.

³Acrylate:maleate copolymer, sodium salt, m.w. 65,000. ⁴Diethylenetriamine pentaacetate, pentasodium salt. ^sMaximum 8% wt. H₂0 in composition.

EXAMPLE VII The composition of Example VI is modified by removal of sufficient Na₂S0₄ to allow for the inclusion of 1% by weight of sodium perborate onohydrate. The resulting composition is useful in water containing chlorine bleaches.

EXAMPLE VIII

The composition of Example I is modified by the inclusion of 3% (wt.) octyl dimethylamine N-oxide dihydrate surfactant (see

"High Active Alkyldimethylamine Oxides", K. R. Smith et al , J.

Amer. Oil Chemists' Soc, 1991, Vol. 68, pp 619-622) to provide additional cleansing performance.

Claims

WHAT IS CLAIMED IS:

1. An automatic dishwashing detergent composition which is substantially free of inorganic phosphate builders and substan¬ tially free of chlorine bleach, characterized in that it comprises:

(a) a monopersulfate bleaching salt in an amount sufficient to provide from 0.18% to 1.3%, by weight, of Available Oxygen;

(b) from 0.01% to 0.5% by weight of an active detersive enzyme;

(c) from 0.1% to 10% by weight of an organic dispersant;

(d) a pH-adjusting agent in an amount sufficient to estab¬ lish the usage pH in the range from 8 to 11;

(e) from 0% to 1.5% by weight of a chlorine scavenger;

(f) from 0% to 40% by weight of a weak nonphosphorus builder;

(g) from 0% to 4% by weight of a bleach stabilizer; and (h) from 0% to 10% by weight of a low-sudsing surfactant.

2. A composition according to Claim 1 wherein the pH-adjusting agent is selected from water-soluble carbonates, bicarbonates, silicates and mixtures thereof.

3. A composition according to Claim 1 wherein the weight ratio of organic dispersant to Available Oxygen is in the range from 0.5:1 to 5:1.

4. A composition according to Claim 1 wherein the enzyme is selected from proteases, amylases and mixtures thereof.

5. A composition according to Claim 1 wherein the water soluble silicate is characterized by a mole ratio of Si0₂:M₂0 of from 1.6 to 3.

6. A composition according to Claim 1 wherein said weak builder is selected from water-soluble citrates and water-soluble gluco- heptanates.

7. A composition according to Claim 1 wherein the organic dispersant is selected from acrylate polymers and acrylate-maleate copolymers.

8. A composition according to Claim 1 wherein the chlorine scavenger is a water-soluble perborate salt.

9. A composition according to Claim 1, characterized in that it comprises: i) from 3.5% to 25% by weight of a monopersulfate bleach of the formula 2KHS0₅-KHS0₄-K₂S0₄; . ii) from 0.02% to 0.2% by weight of a detersive protease or amylase enzyme, or mixtures thereof; iii) from 1% to 7% by weight of a low-sudsing nonionic surfactant; iv) from 5% to 25% by weight of a water-soluble carbonate or bicarbonate ingredient, or mixtures thereof; v) from 4% to 25% by weight of a water-soluble silicate; vi) from 2% to 1.5% by weight of a citrate builder; vii) from 0.1% to 2% by weight of a bleach stabilizer; viii) from 1% to 7% by weight of an organic dispersant; and ix) from 0% to 1.5% by weight of a chlorine bleach scavenger, said composition being in granular form.

10. A method for cleansing tableware in an automatic dishwashing machine, comprising: washing said tableware with an aqueous bath comprising from 1,500 ppm to 4,000 ppm of a composition according to Claim 1;