US20030045437A1

US20030045437A1 - Dishwashing

Info

Publication number: US20030045437A1
Application number: US10/144,912
Authority: US
Inventors: Glenn Ward
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 2001-05-14
Filing date: 2002-05-14
Publication date: 2003-03-06
Also published as: WO2002092751A3; US20050164897A1; ATE528386T1; JP4163519B2; CA2443113C; US20020187910A1; EP1392812B1; CA2443113A1; JP2004535487A; ES2375224T3; MXPA03010366A; EP1392812A2; WO2002092751A2; US7078462B2; US6956016B2

Abstract

A method of washing cookware/tableware in an automatic dishwashing machine having a pre-wash, main-wash and one or more rinse cycles wherein one or more dishwashing products are dosed into the one or more rinse cycles and wherein the dosing regime is such as to provide a rinse cycle concentration factor (C_r) of at least about 1.3×10⁴, preferably at least about 1.8×10⁴more preferably at least about 2.4×10⁴and especially 3.2×10⁴ppm min, wherein C_ris defined as:

\int_{t_{r}}^{t_{e}} c (t) \partial t

wherein c(t) is the wash liquor concentration of dishwashing product as a function of dishwashing time variable t, t_ris the time corresponding to the start of the first rinse, and t_eis the time corresponding to the end of the final rinse. The method provides improved cleaning and finishing of the washed cookware/tableware.

Description

The application is a continuation of patent application GB 0208097.6 filed Apr. 9, 2002, which claims the benefit of GB 0111618.5 filed May 14, 2001, being filed under 35 U.S.C. 120.

TECHNICAL FIELD

The present invention is in the field of dishwashing, in particular it relates to methods for the delivery of dishwashing products into the rinse cycle of an automatic dishwashing machine. The methods allow for an improved cleaning of tough food residues and reduction of filming and spotting of the washed articles.

BACKGROUND OF THE INVENTION

Two of the unsolved problems in the field of automatic dishwashing are those of cleaning tough food residues and of preventing filming and spotting of washed articles, especially glass and plastic articles. Filming and spotting are believed to occur, among other reasons, due to the formation of insoluble salts resulting from the combination between the ions generated from the dishwashing detergent and the ions present in the dishwasher water. Food soils also play a significant role in causing filming and spotting. Traditionally, this problem has been ameliorated by the use of salt in order to soften the water (that is to reduce the concentration of cations, specially Ca ²⁺ and Mg²⁺) and by the use of rinse aid containing sequestrant, dispersant and surfactant which to some extent help to control the hardness of the ions present in the water and to reduce the surface tension of the dishwashing liquor, thus avoiding the formation of liquid droplets and allowing uniform drying of the washed utensils, ameliorating filming and spotting issues.

However, some consumers do not use salt or rinse aid or the water is so hard that salt and rinse aid are not enough to overcome filming and spotting problems. Moreover, the problem of food soils and removal of tough food residues still remains a significant issue.

Nowadays, dishwashers are designed in such a way as to deliver approximately from about 2 to about 6 ml of rinse aid at or towards the end of the final rinse cycle. Sometimes, this amount of rinse aid is not enough to control filming and spotting, however dispenser sizes and delivery programs are fixed parameters determined by dishwashing machine manufacturers and the user has no control over them. A further restriction which needs to be considered when formulating a rinse aid composition is the fact that the rinse aid needs to be stored in the rinse reservoir inside the dishwasher, usually during many cycles and therefore is subject to the temperature changes associated with the dishwashing process. Thus rinse aid compositions need to be very stable in order to withstand these temperature changes without affecting its physical form and/or chemical structure. This usually requires the use of very dilute compositions, which limits even further the amount of actives that can be delivered into the rinse cycle.

Some attempts have been made in order to provide controlled delivery of rinse aid. For example WO-A-00/6684 and WO-A-00/6688 describe a multi-phase tablet comprising a particle which comprises a core and a coating. The substances present in the core are active during the rinse cycle and the coating comprises at least one compound whose solubility increases with a declining concentration of a specific ion in the surrounding medium. WO-A-99/27067 describe a multi-phase tablet with a compressed and non-compressed portion where the non-compressed portion does not dissolve until the rinse cycle. EP-A-851,024 also describes a multi-phase tablet delivering actives during the rinse cycle. However, WO '84, WO '88, WO '67 and EP '24 are capable of delivering only small amount of actives into the rinse cycle. U.S. Pat. No. 5,453,216 describes the delivery of actives in the rinse cycle by means of coated particles. The particles, which are introduced into the pre-wash and into main-wash cycles, comprise a core comprising an inorganic builder salt and a waxy coating having a melting point above 65° C. Particles are said to have a diameter from about 1 to about 2.5 mm. As such, it seems likely that a large proportion of the particles will be flushed away with the main wash liquor at the end of the main wash cycle.

The majority of automatic dishwashers have wash programs which last at least one hour but only a relatively small proportion of the total wash program is devoted to active detersive cleaning (i.e. the main-wash cycle, which lasts for about 20 min, and possibly the pre-wash). The remainder of the program is taken up with one or more post-main wash rinsing cycles. The perfect dishwashing process able to clean even the toughest residues while eliminating rinse-related problems such as filming and spotting within the constraints of current dishwashing machine design, has still to be developed.

In view of the above there is still a need for improving tough food cleaning whilst reducing filming and spotting, especially in those instances where users wish to avoid or limit the use of salt and/or rinse aid and in the case of dishwashing under hard water conditions.

SUMMARY OF THE INVENTION

An automatic dishwashing operation typically comprises three or more cycles: a pre-wash cycle, a main-wash cycle and one or more rinse cycles. In Europe, the pre-wash cycle, when used, is typically a cold water cycle lasting about 6 or 7 min. In the main-wash cycle the water comes in cold and is heated up to about 55 or 65° C., the cycle lasting about 20 min. Rinsing usually comprises two or more separate cycles following the main wash, the first being cold and lasting between about 2 and 5 min, the second one starting cold with heat-up to about 65° C. or 70° C. and lasting about 20 min. The dishwashing machine is filled with cold water at the start of each cycle and emptied at the end of each cycle through a filter. A typical dishwashing machine is designed for the delivery of from about 20 to about 40 grams of detergent from the dispenser into the main-wash and from about 2 to about 6 ml of rinse aid at or towards the end of the final rinse cycle. In the U.S. the pre-wash may itself be followed by a separate rinse cycle prior to the main-wash. For purposes of the invention the term rinse is restricted to rinse cycles following the main-wash.

It has now been found that dishwashing performance can be significantly improved by delivery of one or more detergent products or components thereof into the rinse following the main wash, and especially into a rinse cycle prior to the final rinse and/or into the final rinse, under conditions of concentration and time such that the rinse cycle concentration factors and cofactors as herein defined exceed certain minimum values. As used herein, the term “rinse cycle concentration factor” refers to the integral of wash liquor concentration of detergent product, treated as a time-dependent function, over the period of the rinse, i.e. from the start of the first rinse after the main-wash to the end of the final rinse. The term “pre-final rinse concentration factor” refers to the same integral but taken over the period from the start of the first rinse to the start of the final rinse. The terms “rinse cycle concentration cofactor” and “pre-final rinse cycle concentration cofactor” are analogous quantities specified for individual components of the detergent product, for example, chlorine bleach, protease, etc. The concentration factors and cofactors are calculated herein by trapezoidal graphical integration of the wash liquor concentration function at time intervals of 1 minute over the appropriate time period.

It has also been surprisingly found that the use of liquid or gel detergent for the main-wash cycle combined with the use of similar amounts of liquid or gel detergent during the rinse cycle provides excellent cleaning results with minimum film formation resulting from hardness/detergent interaction. Without being bounded by the theory, it is believed that detergents in solid form (such as powders or tablets) can give rise to the formation of a film onto the washed articles during the main wash, therefore a rinse cycle and rinse aid is needed to prevent this film. Apparently, this film does not occur in the case of liquid or gel detergent, suggesting that the rinse cycle can be used to achieve extra cleaning whilst maintaining good rinsing and finishing performance.

According to a first aspect of the present invention, there is provided a method of washing cookware/tableware in an automatic dishwashing machine having a main-wash, optional pre-wash and one or more post main-wash rinse cycles wherein one or more dishwashing products are dosed into the one or more rinse cycles and wherein the dosing regime is such as to provide a rinse cycle concentration factor (C _r) of at least about 1.3×10⁴, preferably at least about 1.8×10⁴more preferably at least about 2.4×10⁴and especially at least about 3.2×10⁴ppm min, wherein C_ris defined as:

\int_{t_{r}}^{t_{e}} c (t) \partial t

wherein c(t) is the wash liquor concentration of dishwashing product as a function of dishwashing time variable t, t _ris the time corresponding to the start of the first rinse, and t_eis the time corresponding to the end of the final rinse, all times being measured in min from the start of the dishwashing operation.

For calculation purposes, it is assumed that where a dishwashing product takes less than 1 minute to dissolve or to disperse substantially to a particle size of less than 53 μm (270 mesh) after contact with the wash liquor, the product is considered to dissolve instantaneously and the wash liquor concentration of the product as function of time simply equates to the cumulative total of dishwashing product dosed into the wash liquor as a function of time. This assumption generally applies to most liquids, gels and paste-type products. Otherwise, the wash liquor concentration can be determined by means known by the skilled man in the art. For example, in the case of slowly dissolving blocks the weight of the block can be monitored at regular 1 minute time intervals. In the case of powders, samples of wash solution can be taken at regular 1 minute time intervals and filtered, the filtered solid being dried and weighed to quantify the amount of product which is not dissolved, i.e. which does not pass a 270 mesh filter. Measurements are repeated a sufficient number of times to obtain a statistical significance (95% confidence). For the purpose of the present invention it is suitable to deliver powders having fast dissolution times so they will have more time to act.

In a preferred embodiment herein, the dishwashing machine has two or more rinse cycles and the dosing regime is such as to provide a pre-final rinse concentration factor (C _pfr) of at least about 1.0×10³, preferably at least about 3.0×10³, and more preferably at least about 4.0×10³, especially at least about.5.0×10³ppm min, where C_pfris defined as:

\int_{t_{r}}^{t_{f}} c (t) \partial t

wherein t _fis the time corresponding to the start of the final rinse and t_ris as defined above. Achieving a pre-final rinse concentration factor within the specified range is important herein for securing an optimum combination of tough food cleaning and filming/spotting performance.

Thus, according to another aspect of the present invention, there is provided a method of washing cookware/tableware in an automatic dishwashing machine having a main-wash, optional pre-wash and two or more rinse cycles, wherein one or more dishwashing products are dosed into the rinse after the main wash and prior to the final rinse cycle and wherein the dosing regime is such as to provide a pre-final rinse concentration factor (C _pfr) of at least about 1.0×10³preferably at least about 3.0×10³, and more preferably at least about 4.0×10³and especially at least about.5.0×10³ppm min, where C_pfris defined as:

\int_{t_{r}}^{t_{f}} c (t) \partial t

wherein t _ris the time corresponding to the start of the first rinse, and t_fis the time corresponding to the start of the final rinse.

In preferred embodiments two or more dishwashing products are dosed into the rinse and the dosing regime is such as to provide a final rinse concentration factor (C _fr) of at least about 1.2×10³, preferably at least about 5.0×10³more preferably at least about 1.0×10⁴and especially at least about 3.0×10⁴ppm min, wherein C_fris defined as:

\int_{t_{f}}^{t_{e}} c (t) \partial t

wherein t _fis the time corresponding to the start of the final rinse, and t_eis the time corresponding to the end of the final rinse.

In preferred embodiments the dosage concentration of the one or more dishwashing products delivered into the rinse liquor is greater than about 1500 ppm, preferably greater than about 2000 ppm and more preferably greater than about 3000 ppm. Preferably also the one or more dishwashing products are present in the rinse liquor for a period of at least about 5 min, preferably at least about 7 min, more preferably at least about 10 min, and especially at least about 15 min. It is also preferred that the one or more dishwashing products are present in the rinse liquor prior to the final rinse for at least about 2 min, preferably at least about 5 min, more preferably at least about 7.5 min.

In preferred embodiments the dosing regime is also such as to provide one or more of the following rinse cycle concentration cofactors:

a) an alkali concentration cofactor (C _{r, alk}) of at least about 1.0×10³, preferably at least about 3.0×10³, more preferably at least about 5.0×10³and especially at least about 1.0×10⁴ppm min;

b) an acid concentration cofactor (C _{r, ac}) of at least about 3.0×10³, preferably at least about 4.0×10³, more preferably at least about 5.0×10³and specially at least about 1.0×10⁴ppm min;

c) an active chlorine concentration cofactor (C _{r, chl}) of at least about 1.0×10³, preferably at least about 2.0×10³and more preferably at least about 4.0×10³ppm min;

d) an active protease concentration cofactor (C _{r, prot}) of at least about 30, preferably at least about 50 and more preferably at least about 100 ppm min;

e) an active amylase concentration cofactor (C _{r, amyl}) of at least about 5, preferably at least about 8 and more preferably at least about 16 ppm min;

f) an active pectinase concentration cofactor (C _{r, pect}) of at least about 400, preferably at least about 600 and more preferably at least about 1200 ppm min;

g) a total active enzyme concentration cofactor (C _{r, enz}) of at least about 35, preferably at least about 60 and more preferably at least about 120 ppm min;

h) an active oxygen concentration cofactor (C _{r, ox}) of at least about 400, preferably at least about 600 and more preferably at least about 1200 ppm min;

i) a diacyl peroxide concentration cofactor (C _{r, diacyl}) of at least about 400, preferably at least about 600 and more preferably at least about 1200 ppm min;

j) an Al ³⁺ concentration cofactor (C_{r, al},) of at least about 500, preferably at least about 750 and more preferably at least about 1500 ppm min;

k) a Zn ²⁺ concentration cofactor (C_{r, zn}) of at least about 500, preferably at least about 750 and more preferably at least about 1500 ppm min;

l) a surfactant concentration cofactor (C _r,surf) of at least about, preferably at least about 2.0×10³preferably at least about 3.0×10³and more preferably at least about 6.0×10³ppm min;

m) a sequestrant or builder concentration cofactor (C _{r, seq}) of at least about 2.0×10³, preferably at least about 4.0×10³and more preferably at least about 8.0×10³ppm min;

n) a polymeric dispersant concentration cofactor (C _{r, disp}) of at least about 4.0×10², preferably at least about 8.0×10²and more preferably at least about 1.6×10³ppm min;

o) a silicone concentration cofactor (C _{r, sil}) of at least about 3.0×10², preferably at least about 6.0×10²and more preferably at least about 1.2×10³ppm min;

wherein the rinse cycle concentration cofactor (C _{r, aux}) for a given detergent auxiliary (aux) is defined as:

\int_{t_{r}}^{t_{e}} c_{a u x} (t) \partial t

wherein c _aux(t) is the wash liquor concentration of the detergent auxiliary as a function of the dishwashing time variable t. In order to calculate C_{r, aux}samples of the wash liquor are taken at 1 minute intervals throughout the rinse and the corresponding concentration of auxiliary is measured using an appropriate analytical technique. The concentration cofactors are then determined by trapezoidal graphical integration of wash liquor concentration of the specified auxiliary at time intervals of 1 minute. Wash liquor concentrations are determined in known manner, by taking suitably sized aliquots of the wash liquor and performing conventional analytical techniques on the aliquot. In the case of enzymes, active enzyme concentration is generally determined by spectrophotometric or other suitable methods using the substrate, pH, temperature, buffer and incubation conditions set out in the manufacturer's product data sheets and related test methods for the particular enzyme and calibrated against solutions of known specific and total enzyme activity.

For example, in the case of amylases, activity through the wash can be measured by taking 1 ml aliquot every minute. The aliquot is added to 5 ml of phosphate buffered solution (14.42 g Na ₂HPO₄, 2.59 g KH₂PO₄in 1 liter of deionised water, to give a pH of 8.3) and 0.5 ml of 20% w/v sodium sulphite solution, the mixture is placed in a 37° C. water bath and a Phadebas tablet (Available from Pharmacia Ltd.) is added, the mixture is left to incubate for 15 minutes. After 15 minutes the reaction is stopped by the addition of 1 ml of 1M sodium hydroxide. The mixture is filtered and the absorbance of the liquor is measured at 620 nm (using a Pharmacia Biotech Ultropec 2000 spectophotometer) and from here the active enzyme concentration is read from graphs precalibrated against amylases (such as Termamyl) of known specific activity in known active concentration levels.

In the case of proteases, activity through the wash can be measured by taking 1 ml aliquot every minute. The aliquot is added to 0.7 ml of sodium sulphite solution (2.5 g/l), 2 ml of 0.4% N-N-dimethylcasein solution and 1 ml of 0.65% 2,4,6 trinitro benzene sulphonic acid solution. The test is carried out at 49° C. and pH 9.0. The absorbance of the liquor is measured (using a Pharmacia Biotech Ultropec 2000 spectophotometer) and from here the active enzyme concentration is read from graphs precalibrated against proteases (such as Savinase) of known specific activity in known active concentration levels.

Preferred herein from the viewpoint of achieving optimum tough food cleaning and rinsing/finishing performance are wash processes wherein certain active components are delivered into the rinse prior to the final rinse. Thus, according to another aspect of the invention, there is provided a method of washing cookware/tableware in an automatic dishwashing machine having a main-wash, optional pre-wash and two or more rinse cycles, wherein one or more dishwashing products are dosed into the rinse after the main wash and prior to the final rinse cycle and wherein the dosing regime is such as to provide one or more of the following pre-final rinse concentration cofactors (C _{pfr, aux}):

a) an alkali concentration cofactor (C _{pfr, alk}) of at least about 2.0×10², preferably at least about 1.5×10³and more preferably at least about 2.5×10³ppm min;

b) an acid concentration cofactor (C _{pfr, ac}) of at least about 6.0×10², preferably at least about 2.0×10³and more preferably at least about 2.5×10³ppm min;

c) an active chlorine concentration cofactor (C _{pfr, chl}) of at least about 200, preferably at least about 1.0×10³ppm min;

d) an active protease concentration cofactor (C _{pfr, prot}) of at least about 6, preferably at least about 25 ppm min;

e) an active amylase concentration cofactor (C _{pfr, amyl}) of at least about 1, preferably at least about 4 ppm min

f) an active pectinase concentration cofactor (C _{pfr, pect}) of at least about 80, preferably at least about 300 ppm min;

g) a total active enzyme concentration cofactor (C _{pfr, enz}) of at least about 7, preferably at least about 30 ppm min;

h) an active oxygen concentration cofactor (C _{pfr, ox}) of at least about 80, preferably at least about 300 ppm min;

i) a diacyl peroxide concentration cofactor (C _{pfr, diacyl}) of at least about 80, preferably at least about 300 ppm min;

j) an Al ³⁺ concentration cofactor (C_{pfr, al}) of at least about 100, preferably at least about 275 ppm min;

k) a Zn ²⁺ concentration cofactor (C_{pfr, zn}) of at least about 100, preferably at least about 275 ppm min;

l) a surfactant concentration cofactor (C _{pfr, surf}) of at least about 4.0×10², preferably at least about 1.5×10³;

m) a sequestrant or builder concentration cofactor (C _{pfr, seq}) of at least about 4.0×10², preferably at least about 2.0×10³ppm min;

n) a polymeric dispersant concentration cofactor (C _{pfr, disp}) of at least about 80, preferably at least about 4×10²ppm min;

o) a silicone concentration cofactor (C _{pfr, sil}) of at least about 60, preferably at least about 300 ppm min;

wherein the pre-rinse cycle concentration cofactor (C _{pfr, aux}) for a given detergent auxiliary (aux) is defined as:

\int_{t_{r}}^{t_{f}} c_{a u x} (t) \partial t

wherein c _aux(t) is the wash liquor concentration of the detergent auxiliary as a function of the dishwashing time variable t, t_ris the time corresponding to the start of the first rinse, and t_fis the time corresponding to the start of the final rinse.

In other preferred embodiments, two or more dishwashing products are dosed into the rinse and the dosing regime is such as to provide one or more of the following final rinse concentration cofactors:

a) an alkali concentration cofactor (C _{fr, alk}) of at least about 2.4×10², preferably at least about 1.0×10³, more preferably at least about 2.0×10³and especially about 4.0×10³ppm min;

b) an acid concentration cofactor (C _{fr, ac}) of at least about 6.0×10², preferably at least about 2.5×10³, more preferably at least about 4.0×10³and especially about 8.0×10³ppm min;

c) an active chlorine concentration cofactor (C _{fr, chl}) of at least about 200, preferably at least about 1.0×10³more preferably at least about 2.0×10³ppm min;

d) an active protease concentration cofactor (C _{fr, prot}) of at least about 6, preferably at least about 25 more preferably at least about 50 ppm min;

e) an active amylase concentration cofactor (C _{fr, amyl}) of at least about 1, preferably at least about 4 more preferably at least about 8 ppm min

f) an active pectinase concentration cofactor (C _{fr, pect}) of at least about 80, preferably at least about 300 more preferably at least about 600 ppm min;

g) a total active enzyme concentration cofactor (C _{fr, enz}) of at least about 7, preferably at least about 30 more preferably at least about 60 ppm min;

h) an active oxygen concentration cofactor (C _{fr, ox}) of at least about 80, preferably at least about 300 more preferably at least about 600 ppm min;

i) a diacyl peroxide concentration cofactor (C _{fr, diacyl}) of at least about 80, preferably at least about 300 more preferably at least about 600 ppm min;

j) an Al ³⁺ concentration cofactor (C_{fr, al}) of at least about 100, preferably at least about 275 more preferably at least about 550 ppm min;

k) a Zn ²⁺ concentration cofactor (C_{fr, zn}) of at least about 100, preferably at least about 275 more preferably at least about 550 ppm min;

l) a surfactant concentration cofactor (C _{fr, surf}) of at least about 4×10², preferably at least about 1.5×10³more preferably at least about 3.0×10³ppm min;

m) a sequestrant or builder concentration cofactor (C _{fr, seq}) of at least about 4×10², preferably at least about 2×10³more preferably at least about 4.0×10³ppm min;

n) a polymeric dispersant concentration cofactor (C _{fr, disp}) of at least about 80, preferably at least about 4.0×10²more preferably at least about 8.0×10²ppm min;

o) a silicone concentration cofactor (C _{fr, sil}) of at least about 60, preferably at least about 300 more preferably at least about 600 ppm min;

wherein the final rinse cycle concentration cofactor (C _{fr, aux}) for a given detergent auxiliary (aux) is defined as:

\int_{t_{f}}^{t_{e}} c_{a u x} (t) \partial t

wherein c _aux(t) is the wash liquor concentration of the detergent auxiliary as a function of the dishwashing time variable t, t_fis the time corresponding to the start of the final rinse, and t_eis the time corresponding to the end of the final rinse.

In an especially preferred embodiment, the dosing regime is such as to provide a pre-rinse alkali concentration factor (C _{pfr, alk}) of at least about 200, preferably at least about 1500 ppm min, a pre-rinse active chlorine concentration factor (C_{pfr, chl}) of at least about 200, preferably at least about 1000 ppm min, and a final rinse acid concentration cofactor (C_{fr, ac}) of at least about 600, preferably at least about 2500, more preferably at least about 4000 and especially at least about 8000 ppm min.

Preferably also, the dosing regime is such that the rinse liquor at a point prior to the final rinse has a pH greater than about 10, preferably greater than about 11; and at a point during the final rinse has a pH lower than about 8, preferably lower than about 7.

Preferably the one or more dishwashing compositions are delivered into the rinse by means of a trigger-activated mechanical dosing device designed to achieve the requisite concentration factors and cofactors. Suitable for use herein are dosing devices which contain sufficient dishwashing product for a single dishwashing rinse cycle or for a plurality of dishwashing rinse cycles, in the same or different dishwashing operations. Any device capable of storing and dosing one or more dishwashing products at pre-determined times in the rinse cycle is suitable for use herein. The device keeps the dishwashing product/s enclosed until a pre-determined time at which the product/s is/are released, usually by opening of one or more outlets of the device. The outlet opening time can be controlled by any mechanism known in the art, such as for example a timer, a shape memory alloy, a shape memory polymer, a sensor which detects stimulus from the wash liquor (pH, conductivity, pCa, pNa, temperature, motion, turbidity, etc) or some other means capable of providing a physical or chemical trigger.

The device can contain only one compartment or a plurality of compartments for the storage of one or more products. Where there are products containing mutually incompatible ingredients, such products are normally placed in different compartments in the device. For example, it is useful to have separate compartments when bleach and bleach activator are to be delivered into the rinse or when bleach and enzymes are to be delivered into the rinse. Different products can be dosed at the same time or at different times in order to optimise the cleaning and finishing benefits in the dishwashing process.

Other ways to deliver the dishwashing products into the rinse cycle are for example a slow-release block, a single or multi-compartment sachet with sensitive seals (pH, temperature, ionic strength, etc), a single or multi-compartment porous sachet with a pore-occluding coating (sensitive to pH, temperature, ionic strength, etc) or a single or multi-compartment water permeable sachet comprising an encapsulated dishwashing product (sensitive to pH, temperature, ionic strength, etc).

In preferred embodiments, at least one and preferably all of the dishwashing products is/are in liquid or gel form. In the case of solid form products, preferably at least 50% of the solid delivered into the rinse cycle dissolves in less than about 4 min, preferably less than about 3 min, more preferably less than about 2 min and even more preferably less than about 1 min.

In a highly preferred embodiment one or more of the dishwashing products comprises a detergency builder, preferably an organic soluble builder in an amount effective to reduce the concentration of Ca ²⁺ in the rinse liquor below about 70 ppm expressed as calcium carbonate, preferably below about 35 ppm and more preferably below about 18 ppm. Such a low Ca²⁺ concentration is beneficial not only for the washed dishware/tableware but also for the heating element of the dishwasher. The Ca²⁺ in the rinse liquor can be measured using for example atomic absorption.

Without wishing to be bound by the theory, it is believed that a film can be left on the dishware/tableware after the main wash. It has also been found that this film can be dissolved by very soft water, i.e., water containing less than about 70 ppm, preferably less than about 35 ppm and more preferably less than about 18 ppm of Ca ²⁺, a level which may not be attained even with the use of a salt softening system. Herein the soft water is obtained by the use of soluble builders in appropnate concentrations and concentration factors and cofactors. Among the suitable organic soluble builders for use herein are organo aminophosphonic acid, organo diphosphonic acid, carboxylic acid and polycarboxylic acid and their salts and complexes. Preferred for use herein are ethane 1-hydroxy-1,1-diphosphonic acid (HEDP) and citric acid or their salts.

In another preferred embodiment one or more of the dishwashing products comprises a polymeric dispersant, highly preferred herein being a polymeric dispersant which comprises an olefinically unsaturated carboxylic acid monomer and at least one monomer unit selected from sulfonated monomers. The polymeric dispersant is effective in suspending the film that is formed on the dishware/tableware after the main wash cycle. Preferred for use herein are tetrapolymers of 4-sulfophenol methallyl ether, sodium methallyl sulfonate, acrylic acid and methyl methacrylate.

Preferably the concentration of polymeric dispersant in the rinse liquor is less than about 300, preferably less than about 200, more preferably less than about 150 ppm and even more preferably less than about 100 ppm.

Spotting in plasticware after the dishwashing process is a common feature produced as consequence of uneven drying of the water from the surface of the ware after the rinsing step. To help minimize spotting one or more of the dishwashing products preferably comprises a wetting agent capable of providing the rinse liquor with a surface tension of less than about 24 mN/m, preferably less than about 23 mN/m and even more preferably less than about 21 mN/m. The low surface tension of the wash liquor allows for sheeting of the water, avoiding the spotting in plasticware. Preferred wetting agents for use herein are siloxane surfactants especially trisiloxanes.

Also preferred for use herein from the viewpoint of reducing spotting is a chlorine bleaching agent. Chlorine bleach greatly improves cleaning performance of the automatic dishwashing operation, in particular it remove stains left by tea, coffee or fruit juices. Chlorine bleach is also very good in the removal of protein films from dishware/tableware caused by soil food or by enzymes deposition. Additionally chlorine bleach is an excellent sanitizer and germicide.

In another embodiment one or more of the dishwashing products comprises a surface substantive modifying polymer. Surface substantive modifying polymers suitable for use herein are selected from polyvinyl pyrrolidone and copolymers thereof; especially copolymers of polyvinyl pyrrolidone with a comonomer selected from vinyl imidazole, acrylic acid, methacrylic acid, N-oxide and mixtures thereof.

Preferably, the one or more dishwashing products provides the final rinse liquor with a pH of less than about 10, preferably less than about 9 and even more preferably less than about 8 as measured at room temperature.

In another embodiment one or more of the dishwashing products comprises a fibrous food degrading enzyme. The addition of fibrous food degrading enzyme is especially valuable for the cleaning of the machine itself. Usually after the dishwashing process there can be a lot food residues left over in the filter and other parts of the dishwashing machine. The use of machine cleaner products is known in the art, however, these usually necessitate running the machine empty. The present method allows for the simultaneous cleaning of dishware/tableware and the dishwashing machine interior. Suitable fibrous food degrading enzymes for use herein include pectinases and are normally employed at a pH of less than about 7, preferably less than about 6 as measured at room temperature.

DETAILED DESCRIPTION OF THE INVENTION

The present invention envisages a dishwashing method based on the use of one or more rinse cycles to provide chemical cleaning after the main wash and/or to improve finishing of the dishware/tableware by delivering high amounts of actives into the rinse. The actives are preferably delivered early into the rinse and preferably prior to the final rinse so as to provide both tough food cleaning benefits and finishing benefits at one and the same time. Embodiments in which one or more dishwashing products are delivered prior to the final rinse and one or more dishwashing products are thereafter delivered into the final rinse are also highly preferred. According to preferred embodiments of the invention, the dishwashing products are delivered by means of purpose-built dosing devices. Suitable dosing devices allow for the storage of the dishwashing products in one or more compartments and for simultaneous or sequential dosing of the products in one or more cycles, wherein the products are in solid, liquid, gel or paste form.

The method of the invention also envisages the use of products comprising chlorine bleach, organic soluble builders and polymeric dispersants to reduce filming and spotting; the use of products comprising wetting agents to facilitate uniform drying and the use of surface substantive modifying polymers to improve the finishing of dishware/tableware.

Finally, the method of the invention also envisages the use of products comprising fibrous food degrading enzymes which contribute to the cleaning of the machine itself.

The dishwashing products can be delivered using any suitable device capable of delivering a predetermined amount of product at a predetermined time. For example, a dosing device suitable for use herein comprises a housing with at least one opening wherein the opening is removably closed by a cover. Inside the housing, the dosing device comprises at least one product compartment for storing the product to be dosed. The compartment can have any suitable shape sufficient to ensure easy and complete release of its contents. The device can be electrically operated, in which case the device would also comprise at least one compartment for storing electromechanical components. While the dosing device can have any suitable shape, a preferred one is made out of two hemispheres, one comprising at least one product compartment for containing at least one product to be released, and the other hemisphere comprising an electromechanical compartment containing the power supply, at least one sensor, actuator systems and a microchip for driving a logic control program.

By sensor is meant a chip or similar electronic device which detects a stimulus in the dosing device's environment, for example in the wash water (such as pH, temperature, ionic strength, etc). Preferably, the sensor is directly coupled to a microchip which transforms the stimulus into an electric impulse which is then sent to the actuator. The sensor is housed in the electromechanical compartment of the device and secured for example with brackets and screws. The microchip which is preferably integrated to the sensor itself is an electronic circuit which runs a basic program, so called logic control program. The logic control program integrates different parameters of the wash which are sensed in the medium (i.e. the wash water), and also integrates the type of product that needs to be released and the desired rinse cycle concentration factors, in order to calculate at what time(s) during the rinse, said products must be released. The specific construction of the electronic circuit of the microchip will be appropriately chosen by a person skilled in the art.

The sensor structure and construction is adapted to the stimulus to be detected, and the choice of the appropriate sensor construction will be easily determined by a person skilled in the art. One dosing device suitable for use herein comprises at least one sensor, such that it can react to at least one stimulus present in its environment. It will be appreciated that the more stimuli said device detects, the more accurate the product dosing and/or release will be.

The dosing device can alternatively be controlled by means of memory shape alloys or polymers, which properties are determined by temperature.

By dosing device is meant a device with which it is possible to measure the right amount of product to be released during the rinse cycle, for example depending on the wash conditions, including but not limited to the amount of items to be washed, the composition of the washing environment (for instance the wash water), the nature of the product which is used for the wash, the required rinse cycle concentration factors, etc.

The dosing can be done by the user her/himself with instructions as to the requisite dosing regime. For example, this can be done by using the size of the device's compartment to measure the right amount of product to be released at a requisite part of the rinse. In this case, the device comprises a means, for example dosing line-up marks, that will help the user chose the right amount of product. Alternatively, the user can introduce a cartridge of product into the dosing device, said cartridge containing a predetermined amount of product, e.g. for one or several wash(es).

Alternatively, the dosing is done by the device itself, which is constructed so that at least one compartment can be opened and closed again during the wash. In this case, the compartment does not comprise line-up marks, the user fills it completely before the wash. During the rinse cycle, the dosing device first opens to release product, then senses or calculates when the concentration of product is sufficient and finally closes to prevent over-dosing of the product. In this case, the concentration sensing can be done by checking one component which is a characteristic of the product to being released, for example, the level of bleach can be sensed, in case the product to be released is bleach. The skilled person will be able to determine which compound must be sensed, depending on which product is released. Of course, a corresponding and suitable sensor must be integrated to the dosing device in this case, and the control logic program must be adapted accordingly.

Preferably, the dosing device comprises a means to enable it to stand on a flat surface, for example on a table. This means can be for example a flat portion of the housing, an outside surface or a stand. Alternatively, in the case of power operated device, the electronic components which are the heaviest part of said device are located in the bottom portion of said device, so that when the device is put on a flat surface, it always stays in the upright position. Once activated, the dosing device most preferably stays as a single unite, so that the user does not have to remove more than one portion of the device from the dishwashing machine.

The materials used for the housing and the cover might be of any type, and they may be made out of one or several materials. Preferred materials for the housing and the cover are synthetic materials, for example plastic or rubber, so as to be resistant to liquids and/or temperature variations. It is highly preferred that once closed, the dosing device be liquid-tight. Of course, all materials used in the dosing device should be chosen such that they resist the conditions of use. Preferably, they are heat resistant so as to withstand the dish-washing temperatures. Examples of hard materials include but are not limited to polypropylene (PP), polycarbonate (PC), copolymers of butadiene and styrene, and the like.

The housing and the cover are preferably made by injection molding. In case they are made out of more than one material, co-injection molding process will be preferred, where applicable, since it is less expensive than molding several insert portions separately and then assembling them. For instance, co-injection molding can be used for the housing, to make it out of hard plastic, with some portions made out of a non-slipping rubber material. It is preferred that at least some portions of the dosing device's outer surface (including housing and cover) are made out of a rubber-like material, which will help to prevent noise. Preferably, the dosing device is secured to the walls of the dishwashing machine, for example by means of a magnet or by adhesive means.

In the case of a power-operated device, the dosing device comprises at least one means for storing energy and releasing it, such that the contents of said dosing device is released at a given predetermined time during the rinse cycle. It is preferred that the dosing device also comprises at least one sensor which is linked to the means, to determine when the environment, for example the wash water, requires that the dosing device be opened and the product released. Also preferably, the dosing device comprises an actuator which is linked to the cover, so as to activate the opening of said cover during the wash. Finally, the dosing device further comprises a microchip that monitors the data received from the sensors, and gives a signal to the actuator to open said dosing device at the right time during the wash cycle, in order to meet the required concentration factors and cofactors.

The dosing device is preferably portable, that is to say that it is not too bulky and heavy and can easily be handheld and manipulated by a user for in-house usage. Its dimensions must be such that it can be put into a dishwasher. Preferably, its greatest outer dimension does not exceed 20 cm. Also preferably, its overall weight does not exceed 5 kg when empty, more preferably, it does not exceed 2.5 kg when empty, even more preferably its weight is not more than 1 kg when empty.

The dosing device for use herein is preferably self contained. By self contained is meant that the dosing device, once filled with product and closed, can work independently from any other device. Particularly, it comprises its own power source, and all means necessary to determine properly the right time its contents needs to be released, only by sensing its external environment. Alternatively, the power can be transmitted via a coil transmitter, which receives electricity via a remote generator. The sensing and/or microchip means can also be provided as a separate unit with signals for actuating the dosing device being transmitted by Bluetooth or some other wireless communication device.

Alkali materials for use herein are any materials capable of providing the dishwashing liquor with a pH above 7, preferably above 8, more preferably above 10 and even more preferably above 11. Preferred for use herein are caustic agents such as alkali hydroxides, especially sodium hydroxide, potassium hydroxide and mixtures therefore.

Acidic materials for use herein are any materials capable of providing the dishwashing liquor with a pH below 7, preferably below 6, more preferably below 5 and even more preferably below 4. Suitable for use herein are organic acids, for example carboxylic acids, such as citric and succinic acids, polycarboxylic acids, such as polyacrylic acid and also acetic acid boric acid, malonic acid, their derivatives and mixtures thereof. Also suitable for use herein are inorganic acids and their salts, especially useful are salt of inorganic acids containing a cation which plays a role in the dishwashing process as for example aluminium. Preferred for use herein is aluminium sulphate, which provides the dishwashing liquior with an adequate pH and provides glass care benefits.

Organic Soluble Builder

Organic soluble builders for use herein are capable of reducing the concentration of Ca ²⁺ below about 4 ppm, preferably below about 2 ppm and more preferably below 1 ppm. The organic soluble builder is preferably present at a level of from about 1 to about 80%, preferably from about 5 to about 70% and more preferably from about 10 to about 60% by weight of the composition.

Suitable for use herein are organo aminophosphonic acid or one of its salts or complexes. By organo aminophosphonic acid component it is meant herein an organic compound comprising at least one phosphonic acid group, and at least one amino group. The organo aminophosphonic acid component may be present in its acid form or in the form of one of its salts or complexes with a suitable counter cation, and reference herein to the acid component implicitly includes reference to the salts or complexes. Preferably any salts/complexes are water soluble, with the alkali metal and alkaline earth metal salts/complexes being especially preferred.

Suitable organo aminophosphonic acid components for use herein include the amino alkylene poly (alkylene phosphonic acids) and nitrilo trimethylene phosphonic acids. Preferred are diethylene triamine penta (methylene phosphonic acid) and hexamethylene diamine tetra (methylene phosphonic acid).

A preferred component of the dishwashing products used herein is an organo diphosphonic acid or one of its salts or complexes. Said organo diphosphonic acid may act in combination with the organo aminophosphonic acid component to further enhance the prevention of calcium deposit formation. By organo diphosphonic acid it is meant herein an organo diphosphonic acid which does not contain nitrogen as part of its chemical structure. This definition therefore excludes the organo aminophosphonates.

The organo diphosphonic acid component may be present in its acid form or in the form of one of its salts or complexes with a suitable counter cation. Preferably any salts/complexes are water soluble, with the alkali metal and alkaline earth metal salts/complexes being especially preferred. The organo diphosphonic acid is preferably a C1-C4 diphosphonic acid, more preferably a C2 diphosphonic acid, such as ethylene diphosphonic acid, or most preferably ethane 1-hydroxy-1,1-diphosphonic acid (HEDP).

Suitable water-soluble carboxylate or polycarboxylate builders include carboxylic and polycarboxylic acids their salts and complexes. The carboxylate or polycarboxylate builder can be momomeric or oligomeric in type although monomeric polycarboxylates are generally preferred for reasons of cost and performance. Monomeric and oligomeric builders can be selected from acyclic, alicyclic, heterocyclic and aromatic carboxylates.

Suitable carboxylates containing one carboxy group include lactic acid, glycolic acid and ether derivatives thereof as disclosed in Belgian Patent Nos. 831,368, 821,369 and 821,370. Polycarboxylates containing two carboxy groups include succinic acid, malonic acid, (ethylenedioxy) diacetic acid, maleic acid, diglycolic acid, tartaric acid, tartronic acid and fumaric acid and their water-soluble salts, as well as the ether carboxylates described in German Offenlegenschrift 2,446,686, and 2,446,687 and U.S. Pat. No. 3,935,257 and the sulfinyl carboxylates described in Belgian Patent No. 840,623. Polycarboxylates containing three carboxy groups include, in particular, water-soluble citrates, aconitrates and citraconates as well as succinate derivatives such as the carboxymethyloxysuccinates described in British Patent No. 1,379,241, lactoxysuccinates described in British Patent No. 1,389,732, and aminosuccinates described in Netherlands Application 7205873, and the oxypolycarboxylate materials such as 2-oxa-1,1,3-propane tricarboxylates described in British Patent No. 1,387,447. Citric acid and citrates are highly preferred for use herein.

Polycarboxylates containing four carboxy groups include oxydisuccinates disclosed in British Patent No. 1,261,829, 1,1,2,2-ethane tetracarboxylates, 1,1,3,3-propane tetracarboxylates and 1,1,2,3-propane tetracarboxylates.

Polycarboxylates containing sulfo substituents include the sulfosuccinate derivatives disclosed in British Patent Nos. 1,398,421 and 1,398,422 and in U.S. Pat. No. 3,936,448, and the sulfonated pyrolysed citrates described in British Patent No. 1,439,000.

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

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

Polymeric Dispersant

Preferably, polymeric dispersants are used in a level of from about 50 to about 200 ppm, preferably from about 70 to 120 ppm in the rinse liquor. Suitable polymers comprise from about 50 to about 99% by weight, preferably from about 70 to about 98%, most preferably from about 75 to about 95% by weight of an olefinically unsaturated carboxylic acid monomer and from about 1% to about 50%, preferably from about 2 to about 30%, most preferably from about 5 to about 25% by weight of at least one monomer unit selected from the group consisting of

(a) copolymerizable sulfonated monomers,

(b) copolymerizable nonionic monomers or

(c) mixtures of (a) and (b).

The olefinically unsaturated carboxylic acid monomer for use herein is intended to include aliphatic, branched or cyclic, mono- or dicarboxylic acids, the alkali or alkaline earth metal or ammonium salts thereof, and the anhydrides thereof. Useful olefinically unsaturated acids of this class include acrylic acid comonomers typified by acrylic acid itself, methacrylic acid, ethacrylic acid, alpha-chloro-acrylic acid, alpha-cyano acrylic acid, beta methyl-acrylic acid (crotonic acid), alpha-phenylacrylic acid, beta-acryloxy propionic acid, sorbic acid, alpha-chloro sorbic acid, angelic acid, cinnamic acid, p-chloro cinnamic acid, beta-styryl acrylic acid (1-carboxy-4-phenyl butadiene-1,3), itaconic acid, maleic acid, citraconic acid, mesaconic acid, glutaconic acid, aconitic acid, fumaric acid, and tricarboxyethylene.

For the polycarboxylic acid monomers, an anhydride group is formed by the elimination of one molecule of water from two carboxyl groups located on the same polycarboxylic acid molecule. Preferred carboxylic monomers for use in this invention are the monoolefinic acrylic acids having a substituent selected from the class consisting of hydrogen, halogen and hydroxyl groups, monovalent alkyl radicals, monovalent aryl radicals, monovalent aralkyl radicals, monovalent alkaryl radicals and monovalent cycloaliphatic radicals. As used herein, (meth) acrylic acid is intended to include acrylic acid and methacrylic acid. Preferred unsaturated carboxylic acid monomers are acrylic and methacrylic acid, more preferably acrylic acid.

Examples of sulfonate monomers (a) include, but not limited to, allyl hydroxypropanyl sulfonate ether, allylsulfonic acid, methallylsulfonic acid, styrene sulfonic acid, vinyl toluene sulfonic acid, acrylamido alkane sulfonic acid, allyloxybenzene sulfonic acid, 2-alkylallyloxybenzene sulfonic acid such as 4-sulfophenol methallyl ether, and the alkali or alkaline earth metal or ammonium salts thereof.

The copolymerizable nonionic monomers (b) are vinyl or allyl compounds selected from the group consisting of C1-C6 alkyl esters of (meth)acrylic acid, acrylamide and the C1-C6 alkyl-substituted acrylamides, the N-alkyl-substituted acrylamides and the N-alkanol-substituted acrylamides, N-vinyl pyrrolidone or any other vinyl amide. Also useful are the C1-C6 alkyl esters and C1-C6 alkyl half-esters of unsaturated vinylic acids, such as maleic acid and itaconic acid.

Preferred nonionic monomers are selected from the group consisting of methyl (meth)acrylate, mono- and dimethyl maleate, mono- and di-ethyl itaconate, and (meth)allyl acetates, propionates and valerates. Particularly preferred is methyl methacrylate. Minor amounts of crosslinking monomers such as diallyl maleate, alkylene bisacrylarnide and triallyl cyanurate may also be employed herein.

The average molecular weight of the polymers ranges from 1500 to 250,000, preferably from 5,000 to 100,000.

A suitable example of polymeric dispersant include, but are not limited to a tetrapolymer of 4-sulfophenol methallyl ether, sodium methallyl sulfonate, acrylic acid and methyl methacrylate. The monomer unit, sulfophenol methallyl ether, has a formula (I):

CH2═C(CH3)CH2OC6H4SO3M (I)

where M represents hydrogen, alkali metal, alkaline earth metal or ammonium ions.

Other suitable examples of polymeric dispersant include, but are not limited to, a copolymer of acrylic acid and 4-sulfophenol methallyl ether; a copolymer of acrylic acid and 2-acrylamido-2-methylpropane sulfonate; a terpolymer of acrylic acid, 2-acrylamido-2-methylpropane sulfonate and sodium styrene sulfonate; a copolymer of acrylic acid and vinyl pyrrolidone; and a copolymer of acrylic acid and acrylamide. Preferably, the polymer is the tetrapolymer of 4-sulfophenol methallyl ether, sodium methallyl sulfonate, acrylic acid and methyl methacrylate.

Preferred commercial available copolymers include: Alcosperse 240, Aquatreat AR 540 and Aquatreat MPS supplied by Alco Chemical; Acumer 3100 and Acumer 2000 supplied by Rohm & Haas; Goodrich K-798, K-775 and K-797 supplied by B F Goodrich; ACP 1042 supplied by ISP technologies Inc.; and polyacrylic acid/acrylamide supplied by Aldrich. A particularly preferred copolymer is Alcosperse 240 supplied by Alco Chemical.

Wetting Agent

Wetting agents suitable for use herein are surfactants and include anionic, amphoteric, zwitterionic, nonionic and semi-polar surfactants. Preferred nonionic surfactants include silicone surfactants, such as Silwet copolymers, preferred Silwet copolymers include Silwet L-8610, Silwet L-8600, Silwet L-77, Silwet L-7657, Silwet L-7650, Silwet L-7607, Silwet L-7604, Silwet L-7600, Silwet L-7280 and mixtures thereof. Preferred for use herein is Silwet L-77.

Surface Substantive Modifying Polymer

Preferably the surface substantive polymer is selected from the group consisting of homo and copolymers of polyvinyl pyrrolidone (PVP), suitable levels for use herein are from about 0.001 to about 10%, preferably from about 0.01 to about 1% by weight of the dishwashing product and at from about 1 to about 200, preferably from about 20 to about 100 ppm in the rinse liquor. In general terms such homo and copolymers can have an average molecular weight (eg as measured by light scattering) in the range from about 1,000 to about 5,000,000, preferably from about 5,000 to about 500,000. In addition, preferred copolymers comprise at least about 5%, most preferably at least about 15%, especially at least about 40% by weight thereof of the comonomer. Highly preferred comonomers include aromatic monomers such as vinyl imidazole and carboxylic monomors such as acrylic acid and methacrylic acid.

PVP preferred for use herein has an average molecular weight of from about 2,500 to about 400,000, preferably from about 5,000 to about 200,000, more preferably from about 5,000 to about 50,000, and most preferably from about 5,000 to about 15,000. Suitable polyvinylpyrrolidones are commercially available from ISP Corporation, New York, N.Y. and Montreal, Canada under the product names PVP K-15 (viscosity molecular weight of 10,000), PVP K-30 (average molecular weight of 40,000), PVP K-60 (average molecular weight of 160,000), and PVP K-90 (average molecular weight of 360,000). PVP K-15 is also available from ISP Corporation. Other suitable polyvinylpyrrolidones which are commercially available from BASF Corporation include Sokalan HP 165 and Sokalan HP 12. Other polyvinylpyrrolidones known to persons skilled in the detergent field, see for example EP-A-262,897 and EP-A-256,696, are also suitable.

A particularly preferred copolymer of polyvinyl pyrrolidone is N-vinylimidazole N-vinylpyrrolidone (PVPVI) polymers available from for example BASF under the trade name Luvitec VP155K18P. Preferred PVPVI polymers have an average molecular weight of from about 1,000 to about 5,000,000, more preferably from 5,000 to 2,000,000, even more preferably from about 5,000 to about 500,000 and most preferably from about 5,000 to about 15,000. Preferred PVPVI polymers comprise at least 45%, preferably at least 50% N-vinylimidazole monomers. Another suitable PVP copolymer is a quaternized PVPVI, for example, the compound sold under the tradename Luvitec Quat 73W by BASF.

Other suitable copolymers of vinylpyrrolidone for use in the compositions of the present invention are copolymers of polyvinylpyrrolidone and acrylic acid or methacrylic acid.

Fibrous Food Degrading Enzyme

Suitable enzymes for use herein include enzyme which acts to break down pectic bondings. Preferably incorporated into the dishwashing product at a level of from 0.0001% to 2%, preferably from 0.0005% to 0.5%, more preferably from 0.001% to 0.05% active enzyme by weight of dishwashing product and at about 10 to about 200, preferably from about 40 to about 150 ppm in the wash liquor.

Preferred for use herein is polygalacturanase enzyme. By polygalacturanase enzyme it is meant herein any enzyme which acts to break down pectic substances by cleaving the glycosidic bonds between galacturonic acid molecules. Pectic substances may be found in plant tissues, and are common constituents of fruit juices such as orange, tomato and grape juices. Pectic substances contain galacturonic acids and/or their derivatives.

Pectic substances include pectins and pectic acids. Pectins are, in general, polymers made up of chains of galacturonic acids joined by alpha-1-4 glycosidic linkages. Typically, in natural pectins approximately two-thirds of the carboxylic acid groups are esterified with methanol. Partial hydrolysis of these methyl esters gives low methoxyl pectins, which tend to form gels with calcium ions. Complete methyl ester hydrolysis gives pectic acids. are not polygalacturanase.

Other pectic enzymes for use herein include, for example, the pectin methylesterases which hydrolyse the pectin methyl ester linkages, and the pectin transeliminases or lyases which act on the pectic acids to bring about non-hydrolytic cleavage of alpha-4 glycosidic linkages to form unsaturated derivatives of galacturonic acid.

Polygalacturanase enzymes herein include naturally derived polygalacturanase enzymes and any variants obtained by, for example, genetic engineering techniques. Any such variants may be specifically designed with regard to the optimization of performance efficiency in the detergent compositions of the invention. For example, variants may be designed such that the stability of the enzyme to commonly encountered components of such compositions is increased. Alternatively, the variant may be designed such that the optimal pH or temperature performance range of the enzyme variant is tailored to suit the particular detergent application.

Polygalacturanase enzymes may be derived from plants, especially fruits, and from fungal sources. A common fungal source is provided by certain strains of the Aspergillus Niger group. Commercially available pectic enzymes tend to be mixtures of pectic enzymes of the pectin methylesterase, polygalacturonase and pectin lyase types; therefore further purification to isolate polygalacturanase enzymes substantially free of other pectic enzyme using standard enzyme purification techniques is required. Polygalacturanase can be isolated from these commercial mixtures by standard protein separation methods that are well known in the art.

Preferably, the polygalacturanase is obtained through recombinant DNA techniques wherein the genetic material coding only for polygalacturanase is isolated from a natural host and transferred into a suitable production organism, like Aspergillus Niger, Aspergillus Orayze, or Bacillus Subtilus for subsequent fermentation, recovery, and purification of the polygalacturanase protein.

Commercially available pectic enzymes include those sold under the Pectinex AR tradename by Novo Industries A/S, those sold under the Rapidase tradename by International Bio-Synthetics (a division of Gist-Brocades BV), those sold under the Cytolase tradename by Genencor International, and those sold under the tradename, Clarex by Solvay Enzymes. Such enzymes may be used following purification isolate polygalacturanase enzymes substantially free of other pectic enzyme. Preferred are pectic enzyme compositions consisting essentially of polygalacturanase enzymes

Surfactant

In the methods of the present invention surfactant can be used as part of a dishwashing product. For use herein the detergent surfactant is preferably low foaming by itself or in combination with other components (i.e. suds suppressers). Surfactants suitable herein include anionic surfactants such as alkyl sulfates, alkyl ether sulfates, alkyl benzene sulfonates, alkyl glyceryl sulfonates, alkyl and alkenyl sulphonates, alkyl ethoxy carboxylates, N-acyl sarcosinates, N-acyl taurates and alkyl succinates and sulfosuccinates, wherein the alkyl, alkenyl or acyl moiety is C ₅-C₂₀, preferably C₁₀-C₁₈linear or branched; cationic surfactants such as chlorine esters (U.S. Pat. No. 4,228,042, U.S. Pat. No. 4,239,660 and U.S. Pat. No. 4,260,529) and mono C₆-C₁₆N-alkyl or alkenyl ammonium surfactants wherein the remaining N positions are substituted by methyl, hydroxyethyl or hydroxypropyl groups; low and high cloud point nonionic surfactants and mixtures thereof including nonionic alkoxylated surfactants (especially ethoxylatesu derived from C₆-C₁₈primary alcohols), ethoxylated-propoxylated alcohols (e.g., BASF Poly-Tergent® SLF18), epoxy-capped poly(oxyalkylated) alcohols (e.g., BASF Poly-Tergent® SLF18B—see WO-A-94/22800), ether-capped poly(oxyalkylated) alcohol surfactants, and block polyoxyethylene-polyoxypropylene polymeric compounds such as PLURONIC®, REVERSED PLURONIC®, and TETRONIC® by the BASF-Wyandotte Corp., Wyandotte, Mich.; amphoteric surfactants such as the C₁₂-C₂₀alkyl amine oxides (preferred amine oxides for use herein include lauryldimethyl amine oxide and hexadecyl dimethyl amine oxide), and alkyl amphocarboxylic surfactants such as Miranol™ C2M; and zwitterionic surfactants such as the betaines and sultaines; and mixtures thereof. Surfactants suitable herein are disclosed, for example, in U.S. Pat. No. 3,929,678, U.S. Pat. No. 4,259,217, EP-A-0414 549, WO-A-93/08876 and WO-A-93/08874. Surfactants are typically present at a level of from about 0.2% to about 30% by weight, more preferably from about 0.5% to about 10% by weight, most preferably from about 1% to about 5% by weight of dishwashing product and at about 10 to about 2000, preferably from about 20 to about 1000 ppm of the wash liquor. Preferred surfactant for use herein are low foaming and include low cloud point nonionic surfactants and mixtures of higher foaming surfactants with low cloud point nonionic surfactants which act as suds suppresser therefor.

Inorganic Builder

In addiction to the organic soluble builder described hereinabove inorganic builders can also be comprised in the products used herein. Suitable inorganic builders include crystalline layered silicates (EP-A-0164514 and EP-A-0293640) and aluminosilicates inclusive of Zeolites A, B, P, X, HS and MAP. The builder is typically present at a level of from about 1% to about 80% by weight, preferably from about 10% to about 70% by weight, most preferably from about 20% to about 60% by weight of dishwashing product and at from about 10 to about 2000, preferably from about 100 to about 1000 ppm of the wash liquor.

Amorphous sodium silicates having an SiO ₂:Na₂O ratio of from 1.8 to 3.0, preferably from 1.8 to 2.4, most preferably 2.0 can also be used herein although highly preferred from the viewpoint of long term storage stability are compositions containing less than about 22%, preferably less than about 15% total (amorphous and crystalline) silicate.

Enzyme

Additionally or in place of the fibrous food degrading enzymes described hereinabove other enzymes can also be comprised in the products used herein. Enzymes suitable herein include bacterial and fungal cellulases such as Carezyme and Celluzyme (Novo Nordisk A/S); peroxidases; lipases such as Amano-P (Amano Pharmaceutical Co.), M1 Lipase ^Rand Lipomax^R(Gist-Brocades) and Lipolase^Rand Lipolase Ultra^R(Novo); cutinases; proteases such as Esperase^R, Alcalase^R, Durazym^Rand Savinase^R(Novo) and Maxatase^R, Maxacal^R, Properase^Rand Maxapem^R(Gist-Brocades); and α and β amylases such as Purafect Ox Am^R(Genencor) and Termamyl^R, Ban^R, Fungamyl^R, Duramyl^R, and Natalase^R(Novo); and mixtures thereof. Enzymes are preferably added herein as prills, granulates, or cogranulates at levels typically in the range from about 0.1 to about 2000, preferably from about 1 to about 1000, more preferably from about 3 to about 300 mg of active enzyme per 100 g of dishwashing product, determined according to the supplier's specific activity data for the particular enzyme. The total enzyme level is typically at least about 50, preferably at least about 100 and more preferably at about 150 mg/100 g or product, or at least about 2, preferable at least about 4 and more preferably at least about 6 ppm of wash liquor.

Bleaching Agent

Bleaching agents suitable herein include chlorine and oxygen bleaches, especially inorganic perhydrate salts such as sodium perborate mono-and tetrahydrates and sodium percarbonate optionally coated to provide controlled rate of release (see, for example, GB-A-1466799 on sulfate/carbonate coatings), preformed organic peroxyacids and mixtures thereof with organic peroxyacid bleach precursors and/or transition metal-containing bleach catalysts (especially manganese or cobalt) and organic peroxides. Inorganic perhydrate salts are typically incorporated at levels in the range from about 1% to about 40% by weight, preferably from about 2% to about 30% by weight and more preferably from abut 5% to about 25% by weight of dishwashing product. Peroxyacid bleach precursors preferred for use herein include precursors of perbenzoic acid and substituted perbenzoic acid; cationic peroxyacid precursors; peracetic acid precursors such as TAED, sodium acetoxybenzene sulfonate and pentaacetylglucose; pernonanoic acid precursors such as sodium 3,5,5-trimethylhexanoyloxybenzene sulfonate (iso-NOBS) and sodium nonanoyloxybenzene sulfonate (NOBS); amide substituted alkyl peroxyacid precursors (EP-A-0170386); and benzoxazin peroxyacid precursors (EP-A-0332294 and EP-A-0482807). Bleach precursors are typically incorporated at levels in the range from about 0.5% to about 25%, preferably from about 1% to about 10% by weight of product while the preformed organic peroxyacids themselves are typically incorporated at levels in the range from 0.5% to 25% by weight, more preferably from 1% to 10% by weight of product. Bleach catalysts preferred for use herein include the manganese triazacyclononane and related complexes (U.S. Pat. No. 4,246,612, U.S. Pat. No. 5,227,084); Co, Cu, Mn and Fe bispyridylamine and related complexes (U.S. Pat. No. 5,114,611); and pentamine acetate cobalt(III) and related complexes(U.S. Pat. No. 4,810,410). Organic peroxides suitable for use herein include diacyl and tetraacylperoxides, especially dibenzoyl peroxide.

Low Cloud Point Non-Ionic Surfactants and Suds Suppressers

The suds suppressers suitable for use herein include nonionic surfactants having a low cloud point. “Cloud point”, as used herein, is a well known property of nonionic surfactants which is the result of the surfactant becoming less soluble with increasing temperature, the temperature at which the appearance of a second phase is observable is referred to as the “cloud point” (See Kirk Othmer, pp. 360-362). As used herein, a “low cloud point” nonionic surfactant is defined as a nonionic surfactant system ingredient having a cloud point of less than 30° C., preferably less than about 20° C., and even more preferably less than about 10° C., and most preferably less than about 7.5° C. Typical low cloud point nonionic surfactants include nonionic alkoxylated surfactants, especially ethoxylates derived from primary alcohol, and polyoxypropylene/polyoxyethylene/polyoxypropylene (PO/EO/PO) reverse block polymers. Also, such low cloud point nonionic surfactants include, for example, ethoxylated-propoxylated alcohol (e.g., BASF's Poly-Tergent® SLF18) and epoxy-capped poly(oxyalkylated) alcohols (e.g., BASF's Poly-Tergent® SLF18B series of nonionics, as described, for example, in U.S. Pat. No. 5,576,281).

Preferred low cloud point surfactants are the ether-capped poly(oxyalkylated) suds suppresser having the formula:

wherein R ¹is a linear, alkyl hydrocarbon having an average of from about 7 to about 12 carbon atoms, R²is a linear, alkyl hydrocarbon of about 1 to about 4 carbon atoms, R³is a linear, alkyl hydrocarbon of about 1 to about 4 carbon atoms, x is an integer of about 1 to about 6, y is an integer of about 4 to about 15, and z is an integer of about 4 to about 25.

Other low cloud point nonionic surfactants are the ether-capped poly(oxyalkylated) having the formula:

R_IO(R_IIO)_nCH(CH₃)OR_III

wherein, R _Iis selected from the group consisting of linear or branched, saturated or unsaturated, substituted or unsubstituted, aliphatic or aromatic hydrocarbon radicals having from about 7 to about 12 carbon atoms; R_IImay be the same or different, and is independently selected from the group consisting of branched or linear C₂to C₇alkylene in any given molecule; n is a number from 1 to about 30; and R_IIIis selected from the group consisting of:

(i) a 4 to 8 membered substituted, or unsubstituted heterocyclic ring containing from 1 to 3 hetero atoms; and

(ii) linear or branched, saturated or unsaturated, substituted or unsubstituted, cyclic or acyclic, aliphatic or aromatic hydrocarbon radicals having from about 1 to about 30 carbon atoms;

(b) provided that when R ²is (ii) then either: (A) at least one of R¹is other than C₂to C₃alkylene; or (B) R²has from 6 to 30 carbon atoms, and with the further proviso that when R²has from 8 to 18 carbon atoms, R is other than C₁to C₅alkyl.

Other suitable components herein include organic polymers having dispersant, anti-redeposition, soil release or other detergency properties invention in levels of from about 0.1% to about 30%, preferably from about 0.5% to about 15%, most preferably from about 1% to about 10% by weight of composition. Preferred anti-redeposition polymers herein include acrylic acid containing polymers such as Sokalan PA30, PA20, PA15, PA10 and Sokalan CP10 (BASF GmbH), Acusol 45N, 480N, 460N (Rohm and Haas), acrylic acid/maleic acid copolymers such as Sokalan CP5 and acrylic/methacrylic copolymers. Preferred soil release polymers herein include alkyl and hydroxyalkyl celluloses (U.S. Pat. No. 4,000,093), polyoxyethylenes, polyoxypropylenes and copolymers thereof, and nonionic and anionic polymers based on terephthalate esters of ethylene glycol, propylene glycol and mixtures thereof.

Heavy metal sequestrants and crystal growth inhibitors are suitable for use herein in levels generally from about 0.005% to about 20%, preferably from about 0.1% to about 10%, more preferably from about 0.25% to about 7.5% and most preferably from about 0.5% to about 5% by weight of product, for example diethylenetriamine penta (methylene phosphonate), ethylenediamine tetra(methylene phosphonate) hexamethylenediamine tetra(methylene phosphonate), ethylene diphosphonate, hydroxy-ethylene-1,1-diphosphonate, nitrilotriacetate, ethylenediaminotetracetate, ethylenediamine-N,N′-disuccinate in their salt and free acid forms.

The products used herein can contain a corrosion inhibitor such as organic silver coating agents in levels of from about 0.05% to about 10%, preferably from about 0.1% to about 5% by weight of product (especially paraffins such as Winog 70 sold by Wintershall, Salzbergen, Germany), nitrogen-containing corrosion inhibitor compounds (for example benzotriazole and benzimadazole—see GB-A-1137741) and Mn(II) compounds, particularly Mn(II) salts of organic ligands in levels of from about 0.005% to about 5%, preferably from about 0.01% to about 1%, more preferably from about 0.02% to about 0.4% by weight of the product.

Other suitable components herein include colorants, water-soluble bismuth compounds such as bismuth acetate and bismuth citrate at levels of from about 0.01% to about 5%, enzyme stabilizers such as calcium ion, boric acid, propylene glycol and chlorine bleach scavengers at levels of from about 0.01% to about 6%, lime soap dispersants (see WO-A-93/08877), suds suppressors (see WO-93/08876 and EP-A-0705324), polymeric dye transfer inhibiting agents, optical brighteners, perfumes, fillers and clay.

Solvents

Solvents that can be used herein include: i) alcohols, such as benzyl alcohol, 1,4-cyclohexanedimethanol, 2-ethyl-1-hexanol, furfuryl alcohol, 1,2-hexanediol and other similar materials; ii) amines, such as alkanolamines (e.g. primary alkanolamines: monoethanolamine, monoisopropanolamine, diethylethanolamine, ethyl diethanolamine; secondary alkanolamines: diethanolamine, diisopropanolamine, 2-(methylamino)ethanol; ternary alkanolamines: triethanolamine, triisopropanolamine); alkylamines (e.g. primary alkylamines: monomethylamine, monoethylamine, monopropylamine, monobutylamine, monopentylamine, cyclohexylamine), secondary alkylamines: (dimethylamine), alkylene amines (primary alkylene amines: ethylenediamine, propylenediamine) and other similar materials; iii) esters, such as ethyl lactate, methyl ester, ethyl acetoacetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate and other similar materials; iv) glycol ethers, such as ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol butyl ether and other similar materials; v) glycols, such as propylene glycol, diethylene glycol, hexylene glycol (2-methyl-2, 4 pentanediol), triethylene glycol, composition and dipropylene glycol and other similar materials; and mixtures thereof.

Liquid dishwashing products containing low quantities of low molecular weight primary or secondary alcohols such as methanol, ethanol, propanol and isopropanol can be usedherein. Other suitable carrier solvents used in low quantities includes glycerol, propylene glycol, ethylene glycol, 1,2-propanediol, sorbitol and mixtures thereof.

EXAMPLES

Abbreviations used in Examples [0179]

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



FN3	Protease available from Genencor
Natalase	Amylase from Novo Nordisk A/S
Pectinase Ultra SP	Pectinase available from Novo Nordisk A/S
Plurafac 400	C₁₃-C₁₅mixed ethoxylated/propoxylated fatty
	alcohol with an average degree of ethoxylation
	of 3.8 and an average degree of
	propoxylation of 4.5, available from BASF
C₁₄AO	Tetradecyl dimethyl amine oxide
ACNI	Alkyl capped non-ionic surfactant of formula C_9/11
	H_19/23EO₈- cyclohexyl acetal
Alcosperse 240	PAA/MMA/SPEM/SME polymer available
	from Alco Chemical
Citric acid	Citric acid
HEDP	Ethane 1-hydroxy-1,1-diphosphonic acid
Silwet 77	Siloxane surfactant available from Ckwitko
PVNO	Poly-4-vinylpyridine N-oxide available from BASF
STPP	Sodium tripolyphosphate
KOH	Potassium hydroxide
NaGH	Sodium hydroxide
DCICA	Dichloroisocyanuric acid (Sodium Salt)
Percarbonate	Sodium percarbonate of the nominal formula
	2Na₂CO₃.3H₂O₂
Silicate 3:2	Amorphous Sodium Silicate (SiO₂:Na₂O ratio = 3:2)
SLF18	Low foaming surfactant available from BASF
Polygel DKP	Dipotassium phosphate gel available from 3V Inc.
Water	De-ionised water

In the following examples all levels are quoted as parts by weight. [0181]

Examples 1 to 8

A load of dishware/tableware is placed into a Bosch Siemens 6032 dishwashing machine having a 5 liters wash water capacity. The load comprises different soils and different substrates: lasagne baked for 2 hours at 140° C. on Pyrex, lasagne cooked for 2 hours at 150° C. on stainless steel, potato and cheese cooked for 2 hours at 150° C. on stainless steel, egg yolk cooked for 2 hours at 150° C. on stainless steel and sausage cooked for 1 hour at 120° C. followed by 1 hour at 180° C. A Fairy tablet (available from Procter & Gamble) is placed in the dispenser for delivery in the main wash. 20 ml of the compositions of examples 1 to 8 are introduced into a dosing device as previously described which is secured to one of the dishwasher internal walls. The dosing device is programmed in such a way as to open and deliver the product at the start of the first rinse cycle. The dishwashing machine is operated in its normal 55° C. program. The rinse cycle concentration factor is 3×10 ⁴ppm min for each example. The washing method provided excellent removal of cooked-on, baked-on and burnt-on food soils as well as excellent shine, filming and spotting performance.



Example	1	2	3	4	5	6	7	8

FN3	1.9	1.9	1.9	2		1.5	2	1
Natalase	5.75	5.75	5.75	4		5	6	4
Pectinase			2	2	5
Plurafac 400	1.8	1		2		1.5		2
C14A0			2		2	1	1.5
ACM			0.5		1	1	0.5
Alcosperse 240	5	4
Citric acid			25	25	30
HEDP						20	18	22
Silwet 77		1	0.1	0.1	0.5	0.5		0.2
PVNO		0.1		0.1	0.1		0.1	0.2
Perfume	1	0.5	0.5	1	0.3	0.4	0.2	0.8
Dye	0.3	0.4	0.2	0.4	0.2	0.4	0.05	0.1

Water	up to 100

Examples 9 to 12

A load of dishware/tableware is placed into a Bosch Siemens 6032 dishwashing machine having a 5 liters wash water capacity. The load comprises different soils and different substrates: lasagne baked for 2 hours at 140° C. on Pyrex, lasagne cooked for 2 hours at 150° C. on stainless steel, potato and cheese cooked for 2 hours at 150° C. on stainless steel, egg yolk cooked for 2 hours at 150° C. on stainless steel and sausage cooked for 1 hour at 120° C. followed by 1 hour at 180° C. 20 ml of the compositions of examples 9 to 12 are placed in the dispenser for delivery in the main wash. 20 ml of the compositions of examples 9 to 12 are introduced into a dosing device as previously described which is secured to one of the dishwasher internal walls. The dosing device is programmed in such a way as to open and deliver the product at the start of the first rinse cycle. The dishwashing machine is operated in its normal 55° C. program. The rinse cycle concentration factor is 3×10 ⁴ppm min for each example. The washing method provided excellent removal of cooked-on, baked-on and burnt-on food soils as well as excellent shine, filming and spotting performance.



Example	9	10	11	12

STPP	28.00	28.00	28.00	28.00
KOH	5.30	5.30	5.30	5.30
Silicate 3:2	1.0	1.0	1.0	1.0
Polygel DKP	0.55	0.55	0.55	0.55
SLF18	1.25		1.25
C₁₆AO		0.40		0.40
ACNI		3.00		3.00

	Water	up to 100

Examples 13 to 16

A load of dishware/tableware is placed into a Bosch Siemens 6032 dishwashing machine having a 5 liters wash water capacity. The load comprises different soils and different substrates: lasagne baked for 2 hours at 140° C. on Pyrex, lasagne cooked for 2 hours at 150° C. on stainless steel, potato and cheese cooked for 2 hours at 150° C. on stainless steel, egg yolk cooked for 2 hours at 150° C. on stainless steel and sausage cooked for 1 hour at 120° C. followed by 1 hour at 180° C. A Fairy tablet (available from Procter & Gamble) is placed in the dispenser for delivery in the main wash. Dual compartment pouches comprising 5 g of composition A (examples 13 to 16) in a cold water soluble compartment and 10 g of composition B (examples 13 to 16) in a hot water soluble compartment are introduced into a dosing device as previously described which is secured to one of the dishwasher internal walls. The dosing device is programmed in such a way as to open and deliver the pouches at the start of the first rinse cycle. The pouches are designed to deliver composition A into the pre-final rinse cycle and composition B into the final rinse cycle. The dishwashing machine is operated in its normal 55° C. program. The pre-final rinse cycle concentration factor is 5×10[0184] ³ppm min and the final rinse cycle concentration factor is 2×10⁴ppm min for each example. The washing method provided excellent removal of cooked-on, baked-on and burnt-on food soils as well as excellent shine. Examples 13 to 16 were repeated but delivering compositions A and B into the pre-final rinse and final rinse cycles respectively by means of the dosing device herein described. Excellent results were obtained.

Example 13 14 15 16

Composition A

NaOH 50 30 50 30

DCICA 50 70

Percarbonate 50 70

Composition B

Citric acid 88 87 92 97

SLF18 10 11 7

Perfume 2 2 1 3

Claims

What is claimed:

1. A method of washing cookware/tableware in an automatic dishwashing machine wherein one or more dishwashing products are dosed into one or more rinse cycles after the main wash and wherein the dosing regime is such as to provide a rinse cycle concentration factor (C_r) of at least about 1.3×10⁴, preferably at least about 1.8×10⁴, more preferably at least about 2.4×10⁴ppm min and especially 3.2×10⁴wherein C_ris defined as:

\int_{t_{r}}^{t_{e}} c (t) \partial t

wherein c(t) is the wash liquor concentration of dishwashing product as a function of dishwashing time variable t, t_ris the time corresponding to the start of the first rinse, and t_eis the time corresponding to the end of the final rinse.

2. A method according to claim 1 having two or more rinse cycles and wherein the dosing regime is such as to provide a pre-final rinse concentration factor (C_pfr) of at least about 1.0×10³, preferably at least about 3.0×10 ³, more preferably at least about 4.0×10³, and especially at least about 5.0×10³ppm min, where C_pfris defined as:

\int_{t_{r}}^{t_{f}} c (t) \partial t

wherein t_fis the time corresponding to the start of the final rinse.

3. A method of washing cookware/tableware in an automatic dishwashing machine wherein one or more dishwashing products are dosed into the rinse after the main wash and prior to the final rinse cycle and wherein the dosing regime is such as to provide a pre-final rinse concentration factor (C_pfr) of at least about 1.0×10³, preferably at least about 3.0×10³, more preferably at least about 4.0×10³, and especially at least about 5.0×10³ppm min, where C_pfris defined as:

least about 4.0×10³, and especially at least about 5.0×10³ppm min, where C_pfris defined as:

\int_{t_{r}}^{t_{f}} c (t) \partial t

wherein t_ris the time corresponding to the start of the first rinse after the main wash, and t_fis the time corresponding to the start of the final rinse.

4. A method according to claim 1 wherein two or more dishwashing products are dosed into the rinse and wherein the dosing regime is such as to provide a final rinse concentration factor (C_fr) of at least about 1.2×10³, preferably at least about 5.0×10³, more preferably at least about 1.0×10⁴and especially at least about 3.0×10⁴ppm min, wherein C_fris defined as:

\int_{t_{f}}^{t_{e}} c (t) \partial t

wherein t_fis the time corresponding to the start of the final rinse, and t_eis the time corresponding to the end of the final rinse.

5. A method according to claim 1 wherein the dosage concentration of the one or more dishwashing products is at least about 1500, preferably at least about 3000 ppm.

6. A method according to any of claims 1 to 5 wherein the dosing regime is such as to provide one or more of the following rinse cycle concentration cofactors:

a) an alkali concentration cofactor (C_{r, alk}) of at least about 1.0×10³, preferably at least about 3.0×10³, more preferably at least about 5.0×10³and especially at least about 1.0×10⁴ppm min;

b) an acid concentration cofactor (C_{r, ac}) of at least about 3.0×10³, preferably at least about 4.0×10³, more preferably at least about 5.0×10³and specially at least about 1.0×10⁴ppm min;

c) an active chlorine concentration cofactor (C_{r, chi}) of at least about 1.0×10³, preferably at least about 2.0×10³and more preferably at least about 4.0×10³ppm min;

d) an active protease concentration cofactor (C_{r, prot}) of at least about 30, preferably at least about 50 and more preferably at least about 100 ppm min;

e) an active amylase concentration cofactor (C_{r, amyl}) of at least about 5, preferably at least about 8 and more preferably at least about 16 ppm min;

f) an active pectinase concentration cofactor (C_{r, pect}) of at least about 400, preferably at least about 600 and more preferably at least about 1200 ppm min;

g) a total active enzyme concentration cofactor (C_{r, enz}) of at least about 35, preferably at least about 60 and more preferably at least about 120 ppm min;

h) an active oxygen concentration cofactor (C_{r, ox}) of at least about 400, preferably at least about 600 and more preferably at least about 1200 ppm min;

i) a diacyl peroxide concentration cofactor (C_{r, diacyl}) of at least about 400, preferably at least about 600 and more preferably at least about 1200 ppm min;

j) an Al³⁺ concentration cofactor (C_{r, al}) of at least about 500, preferably at least about 750 and more preferably at least about 1500 ppm min;

k) a Zn²⁺ concentration cofactor (C_{r, zn}) of at least about 500, preferably at least about 750 and more preferably at least about 1500 ppm min;

l) a surfactant concentration cofactor (C_r,surf) of at least about, preferably at least about 2.0×10³, preferably at least about 3.0×10³and more preferably at least about 6.0×10³ppm min;

m) a sequestrant or builder concentration cofactor (C_{r, seq}) of at least about 2.0×10³, preferably at least about 4.0×10³and more preferably at least about 8.0×10³ppm min;

n) a polymeric dispersant concentration cofactor (C_{r, disp}) of at least about 4.0×10², preferably at least about 8.0×10²and more preferably at least about 1.6×10³ppm min;

o) a silicone concentration cofactor (C_{r, sil}) of at least about 3.0×10², preferably at least about 6.0×10²and more preferably at least about 1.2×10³ppm min;

wherein the rinse cycle concentration cofactor (C_{r, aux}) for a given detergent auxiliary (aux) is defined as:

\int_{t_{r}}^{t_{e}} c_{a u x} (t) \partial t

wherein c_aux(t) is the wash liquor concentration of the detergent auxiliary as a function of the dishwashing time variable t.

7. A method of washing cookware/tableware in an automatic dishwashing machine wherein one or more dishwashing products are dosed into the rinse after the main wash and prior to the final rinse cycle and wherein the dosing regime is such as to provide one or more of the following pre-final rinse concentration cofactors (C_{pfr, aux}):

a) an alkali concentration cofactor (C_{pfr, alk}) of at least about 2.0×10², preferably at least about 1.5×10³and more preferably at least about 2.5×10³ppm min;

b) an acid concentration cofactor (C_{pfr, ac}) of at least about 6.0×10², preferably at least about 2.0×10³and more preferably at least about 2.5×10³ppm min;

c) an active chlorine concentration cofactor (C_{pfr, chl}) of at least about 200, preferably at least about 1.0×10³ppm min;

d) an active protease concentration cofactor (C_{pfr, prot}) of at least about 6, preferably at least about 25 ppm min;

e) an active amylase concentration cofactor (C_{pfr, amyl}) of at least about 1, preferably at least about 4 ppm min

f) an active pectinase concentration cofactor (C_{pfr, pect}) of at least about 80, preferably at least about 300 ppm min;

g) a total active enzyme concentration cofactor (C_{pfr, enz}) of at least about 7, preferably at least about 30 ppm min;

h) an active oxygen concentration cofactor (C_{pfr, ox}) of at least about 80, preferably at least about 300 ppm min;

i) a diacyl peroxide concentration cofactor (C_{pfr, diacyl}) of at least about 80, preferably at least about 300 ppm min;

j) an Al³⁺ concentration cofactor (C_{pfr, al}) of at least about 100, preferably at least about 275 ppm min;

k) a Zn²⁺ concentration cofactor (C_{pfr, zn}) of at least about 100, preferably at least about 275 ppm min;

l) a surfactant concentration cofactor (C_{pfr, surf}) of at least about 4.0×10², preferably at least about 1.5×10³;

m) a sequestrant or builder concentration cofactor (C_{pfr, seq}) of at least about 4.0×10², preferably at least about 2.0×10³ppm min;

n) a polymeric dispersant concentration cofactor (C_{pfr, disp}) of at least about 80, preferably at least about 4×10²ppm min;

o) a silicone concentration cofactor (C_{pfr, sil}) of at least about 60, preferably at least about 300 ppm min

wherein the pre-rinse cycle concentration cofactor (C_{pfr, aux}) for a given detergent auxiliary (aux) is defined as:

\int_{t_{r}}^{t_{f}} c_{a u x} (t) \partial t

wherein c_aux(t) is the wash liquor concentration of the detergent auxiliary as a function of the dishwashing time variable t, t_ris the time corresponding to the start of the first rinse, and t_fis the time corresponding to the start of the final rinse.

8. A method according to claim 1 wherein two or more dishwashing products are dosed into the rinse and wherein the dosing regime is such as to provide one or more of the following final rinse concentration cofactors:

a) an alkali concentration cofactor (C_{fr, alk}) of at least about 2.4×10², preferably at least about 1.0×10³, more preferably at least about 2.0×10³and especially about 4.0×10³ppm min;

b) an acid concentration cofactor (C_{fr, ac}) of at least about 6.0×10², preferably at least about 2.5×10³, more preferably at least about 4.0×10³and especially about 8.0×10³ppm min;

c) an active chlorine concentration cofactor (C_{fr, chl}) of at least about 200, preferably at least about 1.0×10³more preferably at least about 2.0×10³ppm min;

d) an active protease concentration cofactor (C_{fr, prot}) of at least about 6, preferably at least about 25 more preferably at least about 50 ppm min;

e) an active amylase concentration cofactor (C_{fr, amyl}) of at least about 1, preferably at least about 4 more preferably at least about 8 ppm min

f) an active pectinase concentration cofactor (C_{fr, pect}) of at least about 80, preferably at least about 300 more preferably at least about 600 ppm min;

g) a total active enzyme concentration cofactor (C_{fr, enz}) of at least about 7, preferably at least about 30 more preferably at least about 60 ppm min;

h) an active oxygen concentration cofactor (C_{fr, ox}) of at least about 80, preferably at least about 300 more preferably at least about 600 ppm min;

i) a diacyl peroxide concentration cofactor (C_{fr, diacyl}) of at least about 80, preferably at least about 300 more preferably at least about 600 ppm min;

j) an Al³⁺ concentration cofactor (C_{fr, al}) of at least about 100, preferably at least about 275 more preferably at least about 550 ppm min;

k) a Zn²⁺ concentration cofactor (C_{fr, zn}) of at least about 100, preferably at least about 275 more preferably at least about 550 ppm min;

l) a surfactant concentration cofactor (C_{fr, surf}) of at least about 4×10², preferably at least about 1.5×10³more preferably at least about 3.0×10³ppm min;

m) a sequestrant or builder concentration cofactor (C_{fr, seq}) of at least about 4×10², preferably at least about 2×10³more preferably at least about 4.0×10³ppm min;

n) a polymeric dispersant concentration cofactor (C_{fr, disp}) of at least about 80, preferably at least about 4.0×10²more preferably at least about 8.0×10²ppm min;

o) a silicone concentration cofactor (C_{fr, sil}) of at least about 60, preferably at least about 300 more preferably at least about 600 ppm min

wherein the final rinse cycle concentration cofactor (C_{fr, aux}) for a given detergent auxiliary (aux) is defined as:

\int_{t_{f}}^{t_{e}} c_{a u x} (t) \partial t

wherein c_aux(t) is the wash liquor concentration of the detergent auxiliary as a function of the dishwashing time variable t, t_fis the time corresponding to the start of the final rinse, and t_eis the time corresponding to the end of the final rinse.

9. A method according to claim 1 wherein the dosing regime is such as to provide a pre-rinse alkali concentration factor (C_{pfr, alk}) of at least 200, preferably at least 1500 ppm min, a pre-rinse active chlorine concentration factor (C_{pfr, chl}) of at least 200, preferably at least about 1000 ppm min and a final rinse acid concentration cofactor (C_{fr, ac}) of at least about 600, preferably at least about 2500, more preferably at least about 4000 and especially at least about 8000 ppm min.

10. A method according to claim 1 wherein the rinse liquor at a point prior to the final rinse has a pH greater than about 10, preferably greater than about 11.

11. A method according to claim 1 wherein the rinse liquor at a point during the final rinse has a pH lower than about 8, preferably lower than about 7.

12. A method according to claim 1 wherein the one or more dishwashing products are present in the rinse liquor for at least about 5 min, preferably at least about 10 min, and more preferably for at least about 15 min.

13. A method according to claim 1 wherein the one or more dishwashing products are present in the rinse liquor prior to the final rinse for at least about 5 min, preferably at least about 7.5 min.

14. A method according to claim 1 wherein one or more of the dishwashing products are delivered into the rinse by means of a trigger-activated mechanical dosing device.

15. A method according to claim 14 wherein the dosing device is time-activated or is activated in response to a physical or chemical trigger such as pH, conductivity, pCa, pNa, temperature, motion, turbidity, EC etc.

16. A method according to claim 14 wherein a plurality of dishwashing products are simultaneously dosed into a given rinse cycle.

17. A method according to claim 14 wherein a plurality of dishwashing products are dosed into the same or different rinse cycles at different moments of time.

18. A method according to claim 1 wherein one or more of the dishwashing products are dosed in liquid form.

19. A method according to claim 1 wherein one or more of the dishwashing products are dosed in solid form.

20. A method according to claim 19 wherein at least 50% of the solid delivered into the rinse cycle dissolves in less than about 4 min, preferably less than about 3 min and more preferably less than about 2 min.

21. A method according to claim 1 wherein one or more of the dishwashing products comprises a detergency builder, preferably an organic soluble builder in an amount effective for reducing the concentration of Ca²⁺ in the rinse liquor below about 70 ppm, preferably below about 35 ppm and more preferably below about 18 ppm expressed as calcium carbonate.

22. A method according to claim 1 wherein one or more of the dishwashing products comprise a polymeric dispersant wherein the polymeric dispersant comprises an olefinically unsaturated carboxylic acid monomer and at least one monomer unit selected from sulfonated monomers.

23. A method according to claim 22 wherein the concentration of polymeric dispersant in the rinse liquor is less than about 300, preferably less than about 200 and more preferably less than about 150 ppm.

24. A method according to claim 1 wherein one or more of the dishwashing products comprise a wetting agent capable to provide the rinse liquor with a surface tension of less than about 24 mN/m, preferably less than about 23 mN/m.

25. A method according to claim 24 wherein the wetting agent is a siloxane surfactant.

26. A method according to claim 1 wherein one or more of the dishwashing products comprise a surface substantive modifying polymer.

27. A method according to claim 26 wherein the surface substantive modifying polymer is selected from polyvinyl pyrrolidone and copolymers thereof; especially copolymers of polyvinyl pyrrolidone with a comonomer selected from vinyl imidazole, acrylic acid, methacrylic acid and mixtures thereof.

28. A method according to claim 1 wherein one or more of the dishwashing products comprise a fibrous food degrading enzyme.

29. A method according to claim 28 wherein the fibrous food degrading enzyme is a pectinase.

30. A method according to claim 28 wherein one or more dishwashing products provides the rinse liquor with a pH of less than about 7, preferably less than about 6 as measured at room temperature.

31. A mechanical dosing device for use in an automatic dishwashing machine and which is adapted to deliver one or more dishwashing products into the wash liquor according to the dosing regime set out in claim 1.