EP1151073A1

EP1151073A1 - Method for dishwashing with liquid compositions containing amylase

Info

Publication number: EP1151073A1
Application number: EP00907211A
Authority: EP
Inventors: Peter Robert Foley; Christopher Lamb
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 1999-02-08
Filing date: 2000-02-08
Publication date: 2001-11-07
Also published as: AU2874400A; JP2002536499A; JP2002536497A; AU2874600A; AU2874300A; CA2360654A1; AR017744A1; WO2000046335A1; WO2000046333A1; CZ20012872A3; AU3225400A; JP4107633B2; JP2002536500A; WO2000046334A1; TR200102231T2; WO2000046331A1; JP2002536498A; EP1151075A1; EP1151070A1; BR0008066A

Abstract

Method for cleaning a substrate in a manual dishwashing operation consisting essentially of the steps of: contacting an absorbing liquid detergent device with a liquid dishwashing detergent composition, and contacting the substrate with the absorbing liquid detergent device for a sufficient amount of time to provide effective cleaning benefits to the substrate; the liquid dishwashing detergent composition itself comprises from about 0.0001 % to about 5 %, of an amylase enzyme; and at least about 0.5 of a suds booster.

Description

METHOD FOR DISHWASHING WITH LIQUID COMPOSITIONS CONTAINING AMYLASE

TECHNICAL FIELD

The present invention relates to methods for washing kitchen articles (dishware. cookware etc.) with liquid dishwashing detergent compositions containing amylase enzymes and which exhibit excellent greasy soil removal performance.

BACKGROUND OF THE INVENTION

Light-duty liquid (LDL) or gel detergent compositions useful for manual dishwashing are well known in the art. Such products are generally formulated to provide a number of widely diverse performance and aesthetics properties and characteristics. First and foremost, liquid or gel dishwashing products must be formulated with types and amounts of surfactants and other cleaning adjuvants that will provide acceptable solubi zation and removal of food soils, especially grease, fat and other hydrophobic soils, from dishware being cleaned with aqueous solutions of these dishwashing products.

Heavily soiled dishware can present special problems during manual dishwashing operations. Kitchen articles such as plates, utensils, pots, pans, crockery and the like may be heavily soiled in the sense that relatively large amounts of food soils and residues, particularly polymerized and burnt-on greasy soils, may still be found on the dishware at the time such soiled dishware is to be manually washed. Such soil residues may be tenaciously adhered or stuck to the surfaces of the dishware to be cleaned as the result of the food soils present, the nature of the dishware surfaces involved or even the type of cooking operations to which the soiled dishware had been subjected.

These problems of soil removal are compounded when a consumer cleans kitchen articles using the "direct application" method. In this method, dishwashing detergent (diluted or undiluted) is either applied directly to the kitchen article itself or the detergent is applied to a moist sponge or cloth which is then contacted with the kitchen article. The kitchen articles to be cleaned are then, washed and rinsed under running water While the direct application method has the advantage of increasing the product concentration that is applied to a kitchen article it has the disadvantage of generally being performed with warm or cold water, which reduces the effectiveness of the cleaning process and particularly the effectiveness on cleaning starch-based soils.

Accordingly, there is a continuing effort by formulators of liquid dishwashing compositions to incorporate additional components into LDL detergents to improve the performance of the "direct application" cleaning method on removing food soils and cleaning kitchen articles.

SUMMARY OF THE INVENTION It has now been determined that the cleaning efficacy of the direct application method may be improved by performing the direct application method with a liquid dishwashing composition that contains amylase enzymes. These amylase enzymes are particularly effective in enhancing cleaning performance on starch soils in a direct application method, because the amylase enzymes act as a catalyst for starch hydrolysis.

Thus the present invention relates to a method for cleaning a substrate m a manual dishwashing operation consisting essentially of the steps of contacting an absorbing liquid detergent device with a liquid dishwashing detergent composition; and contacting the substrate with the absorbing liquid detergent device for a sufficient amount of time to provide effective cleaning benefits to the substrate; wherein the liquid dishwashing detergent composition compπses:(ι) from about 0.0001% to about 5%, of an amylase enzyme; and (n) at least about 0.5% of a suds booster. All parts, percentages and ratios used herein are expressed as percent weight unless otherwise specified. All documents cited are, in relevant part, incorporated herein by reference Unless otherwise noted all pH values reported for a composition are as measured as 10% aqueous solution.

DETAILED DESCRIPTION OF THE INVENTION Definitions - As used herein the term "light duty liquid detergent composition" (LDL) refers to those compositions which are employed in manual (i.e. hand) dishwashing.

By "kitchen articles" it is meant substrates such as cookware, flatware, dishware, silverware and other articles commonly found in the kitchen and used for the preparation, consumption and serving of food as well as those articles used for cleaning up at the conclusion of a meal or other food preparation. CLEANING METHODS

One of the mostly widely-used cleaning methods by consumer is the "direct application" method. In the direct application method. These problems of soil removal are compounded when a consumer cleans kitchen articles using the "direct application" method In this method, dishwashing detergent (diluted or undiluted) is either applied directly to either the kitchen article itself or the detergent is applied to a moist sponge or cloth which is then contacted with the kitchen article The kitchen articles to be cleaned are then, washed and πnsed under running cold or warm water The "direct application" method is in contrast to the "full sink" approach in which a kitchen sink (or a wash tub placed within a kitchen sink) is filled with water (typically at a temperature of between 35°C to 45°C) and liquid dishwashing detergent is added to the water to form a dilute cleaning solution. The articles to be cleaned are then immersed in the dilute cleaning solution where they are cleaned by contacting the soiled surface of the dish with a cloth, sponge, or similar article. For a more detailed discussion of cleaning methods, see Surfactants in Consumer Products (Edited by J. Falbe), pp. 308-314, Springer- Verlag, Berlin: 1986, U. S. Pat. No 5,415,814, to Ofosu-Asante, both of which are hereby incorporated by reference.

Many consumers prefer the direct application approach because it is more convenient than the full-sink method. This particularly true of consumers who have small kitchen areas or who already possess an automatic dishwasher and manually clean only the occasional dish or only those dishes that will not amply fit inside their automatic dishwasher. Additionally, the direct application method has become the predominant method for consumers in Japan, Latin America and much of Asia.

Specifically, the direct application method of cleaning a substrate (i.e. a kitchen article) consists essentially of two steps. In a first step, a device which is capable of receiving and absorbing a liquid dishwashing detergent is contacted with a liquid dishwashing detergent composition. The device is a sponge, cloth or similar article is preferably moistened or wetted with water before being contacted with the detergent composition. In a second step, the substrate is contacted with the absorbing liquid detergent device for a sufficient amount of time to provide effective cleaning benefits to the substrate, typically for a period of time ranging from about 1 to about 10 seconds, although the actual time will vary with each application and user. Preferably the contacting of the device to the dish surface is accompanied by a concurrent scrubbing of the article or substrate surface.

The first and second steps may be earned out m any order. For example, the liquid dishwashing detergent composition could be applied (e.g. by pouring or spraying) directly onto the surface of substrate or kitchen article and then the substrate or kitchen article contacted by the absorbing liquid detergent device; m this manner the liquid dishwashing detergent and the device would be brought into contact with another as is required by the invention. Or as may more typically be the case, liquid dishwashing detergent could be applied directly to the absorbing liquid detergent device and received and absorbed therein: and then the device would be applied to the kitchen article or substrate.

In an optional step, the direct application method further consists of a pretreatment step which occurs before the substrate or kitchen article is contacted by either the liquid dishwashing detergent composition or the absorbing liquid detergent device. In this pretreatment step the substrate is contacted with a solution comprising water or a dilute dishwashing detergent solution for a sufficient amount of time to hydrate the soil material adhered to the surface of the substrate.

The direct application method consists essentially of the first and second steps, and optionally the third step of pretreatment. The method may also consist of other steps which do not materially affect the basic and novel properties of the method. Thus other steps may be included within this method provided that these additional steps do not change this direct application method to some other type of cleaning method, e.g. full sink etc.

The direct application method has found much preference with consumers and it has the advantage of generally increasing the concentration of the detergent/water mixture being applied to the kitchen article or substrate. But it has the disadvantage of generally being done at cold or warm water temperatures which deleteπously affects cleaning performance because soils particles are not as soluble in cold or warm water as they would be in hot water.

It is thus an essential part of the present invention that the direct application method be performed with a liquid dishwashing detergent composition that contains amylase enzymes. As discussed above, these amylase enzymes provide significant cleaning benefits on starch-based soils and thus provide partial compensation for the cleaning benefits lost due the fact that direct applications methods are performed m cold or warm water. Suitable and preferred amylase enzyme species are discussed in greater detail below.

ENZYMES

Detergent compositions of the present invention comprise at least one amylase enzyme and (if desirable) other enzymes which provide cleaning performance benefits.

Amylase - Amylases (α and/or β) can be included for removal of carbohydrate-based stains. Suitable amylases are Termamyl® (Novo Nordisk), Fungamyl® and BAN® (Novo Nordisk). The enzymes may be of any suitable origin, such as vegetable, animal, bacteπal, fungal and yeast origin. Amylase enzymes are normally incorporated in the detergent composition at levels from 0.0001% to 2%, preferably from about 0.0001% to about 0.5%, more preferably from about 0.0005% to about 0.1%, even more preferably from about 0.001% to about 0.05% of active enzyme by weight of the detergent composition. A particularly preferred species of amylase enzyme is an amylase enzyme having a specific activity at least 25% higher than the specific activity of Termamyla at a temperature range of 25°C to 55°C and at a pH value in the range of 8 to 10, measured by the Phadebasa a- amylase activity assay. This species is preferred because it is specially designed to work well in cold or warm water; thus the use of this species can almost entirely compensate for the loss of starch-cleaning performance suffered when a substrate is cleaned in cold or warm water

Amylase enzymes also include those described in W095/26397 and in co-pending application by Novo Nordisk PCT/DK96/00056. Other specific amylase enzymes for use in the detergent compositions of the present invention therefore include :

(a) The α-amylases (discussed above) and characterised by having a specific activity at least 25% higher than the specific activity of Termamyl® at a temperature range of 25°C to 55°C and at a pH value in the range of 8 to 10, measured by the Phadebas® α-amylase activity assay. Such

Phadebas® α-amylase activity assay is described at pages 9-10, W095/26397. (b) α-amylases according (a) comprising the ammo sequence shown in the SEQ ID listings in the above cited reference, or an α-amylase being at least 80% homologous with the ammo acid sequence shown in the SEQ ID listing.

(c) α-amylases according (a) obtained from an alkalophihc Bacillus species, compπsing the following ammo sequence in the N-termmal . His-His-Asn-Gly-Thr-Asn-Gly-Thr-Met-Met-Gln- Tyr-Phe-Glu-Trp-Tyr-Leu-Pro-Asn-Asp.

A polypeptide is considered to be X% homologous to the parent amylase if a compaπson of the respective ammo acid sequences, performed via algorithms, such as the one described by Lipman and Pearson in Science 227, 1985, p. 1435, reveals an identity of X%

(d) α-amylases according (a-c) wherein the α-amylase is obtainable from an alkalophihc Bacillus species; and in particular, from any of the strains NCEB 12289, NCEB 12512, NCIB 12513 and

DSM 935.

In the context of the present invention, the term "obtainable from" is intended not only to indicate an amylase produced by a Bacillus strain but also an amylase encoded by a DNA sequence isolated from such a Bacillus strain and produced in an host organism transformed with said DNA sequence.

(e)α-amylase showing positive lmmunological cross-reactivity with antibodies raised against an α-amylase having an ammo acid sequence corresponding respectively to those α-amylases m (a- d). (f) Variants of the following parent α-amylases which (1) have one of the amino acid sequences shown in corresponding respectively to those α-amylases in (a-e), or (π) displays at least 80% homology with one or more of said amino acid sequences, and or displays immunological cross- reactivity with an antibody raised against an α-amylase having one of said amino acid sequences, and/or is encoded by a DNA sequence which hybπdizes with the same probe as a DNA sequence encoding an α-amylase having one of said amino acid sequence, in which vaπants :

1. at least one amino acid residue of said parent α-amylase has been deleted; and/or

2. at least one amino acid residue of said parent α-amylase has been replaced by a different ammo acid residue; and/or 3 at least one ammo acid residue has been inserted relative to said parent α-amylase; said variant having an α-amylase activity and exhibiting at least one of the following properties relative to said parent α-amylase : increased thermostabi ty, increased stability towards oxidation, reduced Ca ion dependency, increased stability and or α- amylolytic activity at neutral to relatively high pH values, increased α-amylolytic activity at relatively high temperature and increase or decrease of the lsoelectπc point (pi) so as to better match the pi value for α-amylase variant to the pH of the medium. Said variants are descnbed in the patent application PCTJDK96/00056.

Other amylases suitable herein include, for example, α-amylases descnbed m GB 1,296,839 to Novo; RAPIDASE®, International Bio-Synthetics, Inc. and TERMAMYL®, Novo. FUNGAMYL® from Novo is especially useful. Engineering of enzymes for improved stability, e.g., oxidative stability, is known. See, for example j. Biological Chem., Vol. 260, No. 1 1, June 1985, pp. 6518-6521. Certain preferred embodiments of the present compositions can make use of amylases having improved stability m detergents such as automatic dishwashing types, especially improved oxidative stability as measured against a reference-point of TERMAMYL® in commercial use in 1993. These preferred amylases herein share the charactenstic of being

"stability-enhanced" amylases, charactenzed, at a minimum, by a measurable improvement in one or more of: oxidative stability, e.g., to hydrogen peroxide/tetraacetylethylenediamme m buffered solution at pH 9-10; thermal stability, e.g., at common wash temperatures such as about 60°C; or alkaline stability, e.g., at a pH from about 8 to about 1 1, measured versus the above-identified reference-point amylase. Stability can be measured using any of the art-disclosed technical tests See, for example, references disclosed m WO 9402597. Stability-enhanced amylases can be obtained from Novo or from Genencor International One class of highly preferred amylases herein have the commonality of being denved using site -directed mutagenesis from one or more of the Bacillus amylases, especially the Bacillus α-amylases, regardless of w hether one, two or multiple amylase strains are the immediate precursors. Oxidative stability-enhanced amylases vs the above-identified reference amylase are preferred for use, especially in bleaching, more preferably oxygen bleaching, as distinct from chlorine bleaching, detergent compositions herein Such preferred amylases include (a) an amylase according to the hereinbefore incorporated WO 9402597, Novo, Feb. 3, 1994, as further illustrated by a mutant in which substitution is made, using alanine or threomne, preferably threonine, of the methionine residue located in position 197 of the B. cheniformis alpha-amylase, known as TERMAMYL®, or the homologous position variation of a similar parent amylase, such as B. amylohquefaciens, B. subtihs, or B. stearothermophilus; (b) stability-enhanced amylases as descnbed by Genencor International in a paper entitled "Oxidatively Resistant alpha-Amylases" presented at the 207th Amencan Chemical Society National Meeting, March 13-17 1994, by C. Mitchmson. Therein it was noted that bleaches m automatic dishwashing detergents inactivate alpha-amylases but that improved oxidative stability amylases have been made by Genencor from B. hcheniformis NCIB 8061. Methionine (Met) was identified as the most likely residue to be modified. Met was substituted, one at a time, in positions 8, 15, 197, 256, 304, 366 and 438 leading to specific mutants, particularly important being M197L and M197T with the M197T vaπant being the most stable expressed variant. Stability was measured in CASCADE® and SUNLIGHT®; (c) particularly preferred amylases herein include amylase vaπants having additional modification in the immediate parent as descnbed in WO 9510603 A and are available from the assignee, Novo, as

DURAMYL®. Other particularly preferred oxidative stability enhanced amylase include those descnbed in WO 9418314 to Genencor International and WO 9402597 to Novo. Any other oxidative stability-enhanced amylase can be used, for example as derived by site-directed mutagenesis from known chimeπc, hybπd or simple mutant parent forms of available amylases. Other preferred enzyme modifications are accessible. See WO 9509909 A to Novo.

Other Enzymes - Although amylase enzymes provide excellent cleaning benefits when included m a detergent composition, it is preferred that they be used as one part of a cocktail of conventional applicable enzymes like protease, amylase, pase, cutinase and/or cellulase. Enzymes when present in the compositions, at from about 0.0001% to about 5% of active enzyme by weight of the detergent composition. Other enzymes suitable for use in the present invention include cellulases, hemicellulases, peroxidases, proteases, hpases, cutmases, pectmases, xylanases, reductases, oxidases, phenoloxidases, poxygenases, hgnmases, pullulanases, tannases, pentosanases, malanases, β-glucanases, arabinosidases or mixtures thereof. Preferred proteolytic enzymes, then, are selected from the group consisting of Alcalase ® (Novo Industπ A/S), BPN', Protease A and Protease B (Genencor), and mixtures thereof Protease B is most preferred.

Further non-limiting examples of suitable and preferred enzymes are disclosed in U. S. Pat. No. 5,990,065, to Vinson et al., issued Nov. 23, 1999, which is hereby incorporated by reference.

While the deletenous effects are not as severe enzyme stability may also be adversely affected by certain citric acid and salts thereof (citrates), as is discussed below in the section on builder materials. Composition pH

Dishwashing compositions of the invention will be subjected to acidic stresses created by food soils when put to use, i.e., diluted and applied to soiled dishes. If a composition with a pH greater than 7 is to be more effective, it preferably should contain a buffeπng agent capable of providing a generally more alkaline pH m the composition and in dilute solutions. Dishwashing compositions of the present invention will thus contain from about 0.1 % to 15%, preferably from about 1% to 10%, most preferably from about 2% to 8%, by weight, of a buffenng agent. The pKa value of this buffering agent should be about 0.5 to 1.0 pH units below the desired pH value of the composition (determined as descnbed above Preferably, the pKa of the buffenng agent should be from about 7 to about 12. Under these conditions the buffenng agent most effectively controls the pH while using the least amount thereof.

Preferred inorganic buffers/alkalinity sources include the alkali metal carbonates, alkali metal hydroxides, sodium carbonate, and sodium hydroxide.

The buffeπng agent may be an active detergent in its own πght, or it may be a low molecular weight, organic or inorganic matenal that is used m this composition solely for maintaining an alkaline pH. Preferred buffeπng agents for compositions of this invention are nitrogen-containing matenals. Some examples are amino acids such as lysme or lower alcohol amines like mono-, di-, and tπ-ethanolamme. The diammes, descnbed in detail above, also act as buffeπng agents and are preferred buffenng agents Preferred buffeπng system for use m the present detergent compositions include a combination of 0.5 % diamine and 2.5 % citrate and a combination of 0.5 % diamme, 0.75 % potassium carbonate and 1.75 % sodium carbonate. Other preferred nitrogen-containing buffenng agents are Tπ(hydroxymethyl)amιno methane (HOCH2)3CNH3 (TRIS), 2-amιno-2-ethyl-l,3-propanedιol, 2-amιno-2-methyl-propanol, 2- amιno-2-methyl-l,3-propanol, disodium glutamate, N-methyl diethanolamide, 1,3-dιammo- propanol N,N'-tetra-methyl-l,3-dιammo-2-propanol, N,N-bιs(2-hydroxyethyl)glycιne (bicine) and N-tπs (hydroxymethyl)methyl glycine (tncme). Mixtures of any of the above are also acceptable. For additional buffers see McCutcheon's EMULSIFIERS AND DETERGENTS, North Amencan Edition, 1997, McCutcheon Division, MC Publishing Company Kirk and WO 95/07971 both of which are incorporated herein by reference

SURFACTANTS

The compositions of this invention comprise from about 5 % to about 90 %, more preferably from about 25 % to about 70 % by weight surfactant.

Anionic Surfactants - The anionic surfactants useful in the present invention are preferably selected from the group consisting of linear alkylbenzene sulfonate, alpha olefin sulfonate, paraffin sulfonates, alkyl ester sulfonates, alkyl sulfates, alkyl alkoxy sulfate, alkyl sulfonates, alkyl alkoxy carboxylate, alkyl alkoxylated sulfates, sarcosmates, tauπnates, and mixtures thereof. An effective amount, typically from about 0.5% to about 90%, preferably about 5% to about 50%, more preferably from about 10 to about 30%, by weight of anionic detersive surfactant can be used in the present invention.

Suitable examples of anionic surfactants may be found m copendmg provisional patent application of Chandπka Kastuπ et al., entitled "Liquid Detergent Compositions Compπsing Polymeric Suds Enhancers", having P & G Case No. 6938P, seπal no. 60/066,344 and filed on November 21, 1997, which is hereby incorporated by reference. Further examples of suitable anionic surfactants are given in "Surface Active Agents and Detergents" (Vol. I and II by

Schwartz, Perry and Berch). A vanety of such surfactants are also generally disclosed in U.S Patent 3,929,678, issued December 30, 1975 to Laughhn, et al. at Column 23, line 58 through Column 29, line 23. Suitable anionic surfactants may further be found in U.S. Pat. No. 5,415,814 issued 16 May 1995, to Ofosu-Asante et al., all of which are hereby incorporated by reference. Amphotenc surfactants - The amphotenc surfactants useful m the present invention are preferably selected from amme oxide surfactants. Amine oxides are semi-polar noniomc surfactants and include water-soluble amine oxides containing one alkyl moiety of from about 10 to about 18 carbon atoms and 2 moieties selected from the group consisting of alkyl groups and hydroxyalkyl groups containing from about 1 to about 3 carbon atoms; water-soluble phosphme oxides containing one alkyl moiety of from about 10 to about 18 carbon atoms and 2 moieties selected from the group consisting of alkyl groups and hydroxyalkyl groups containing from about 1 to about 3 carbon atoms; and water-soluble sulfoxides containing one alkyl moiety of from about 10 to about 18 carbon atoms and a moiety selected from the group consisting of alkyl and hydroxyalkyl moieties of from about 1 to about 3 carbon atoms. Semi-polar amphotenc detergent surfactants including amine oxide surfactants are discussed in greater detail in U.S. Pat. No 5,167,872, issued December 1, 1992, to Pancheπ et al These amine oxide surfactants in particular include Ci _Q-Cig alkyl dimethyl amme oxides and Cg-Ci2 alkoxy ethyl dihydroxy ethyl amine oxides Also suitable are amine oxides such as propyl amine oxides, represented by the formula

wherein R, is an alkyl, 2-hydroxyalkyl, 3 -hydroxyalkyl, or 3-alkoxy-2-hydroxypropyl radical in which the alkyl and alkoxy, respectively, contain from about 8 to about 18 carbon atoms, R₂ and R₃ are each methyl, ethyl, propyl, isopropyl, 2-hydroxyethyl, 2-hydroxypropyl, or 3- hydroxypropyl and n is from 0 to about 10.

Other suitable, non-limiting examples of amphotenc detergent surfactants that are useful in the present invention include amido propyl betaines and denvatives of aliphatic or heterocyclic secondary and ternary ammes in which the aliphatic moiety can be straight chain or branched and wherein one of the aliphatic substituents contains from about 8 to about 24 carbon atoms and at least one aliphatic substituent contains an anionic water-solubi zing group.

Further examples of suitable amphotenc surfactants are given in "Surface Active Agents and Detergents" (Vol. I and II by Schwartz, Perry and Berch), hereby incorporated by reference Preferably the amphotenc surfactant is present in the composition in an effective amount, more preferably from about 0.1% to about 20%, even more preferably about 0.1% to about 15%, even more preferably still from about 0.5% to about 10%,by weight.

Noniomc Surfactants - Examples of nomonic detergent surfactants that are useful m the present invention are generally disclosed m U.S. Pat. No. 3,929,678, Laughhn et al., issued Dec. 30, 1975, at column 13, line 14 through column 16, line 6, incorporated herein by reference. These include:

(i) the polyethylene, polypropylene, and polybutylene oxide condensates of alkyl phenols.;

(u) alcohol ethoxylates which are the condensation products of aliphatic alcohols with from about 1 to about 25 moles of ethylene oxide. They are represented by the general formula: R(OCH₂CH₂)_nOH .

(in) another type of noniomc co-surfactant suitable for use in combination with the polyhydroxy fatty acid amides in the noniomc surfactant component herein compnses the ethylene oxide-propylene oxide block co-polymers that function as polymenc surfactants (these are also discussed separately under the solvents heading);

(IV) the condensation products of ethylene oxide with a hydrophobic base formed by the condensation of propylene oxide with propylene glycol; and

(v) alkylpolysacchaπdes disclosed in U.S. Pat. No. 4,565,647, Llenado, issued Jan. 21, 1986, having a hydrophobic group containing from about 6 to about 30 carbon atoms, preferably from about 10 to about 16 carbon atoms and a polysacchande.

Secondary Surfactants - Secondary detersive surfactant can be selected from the group consisting of catiomcs, ampholytics, zwitteπonics, and mixtures thereof. By selecting the type and amount of detersive surfactant, along with other adjunct ingredients disclosed herein, the present detergent compositions can be formulated to be used in the context of laundry cleaning or in other different cleaning applications, particularly including dishwashing. The particular surfactants used can therefore vary widely depending upon the particular end-use envisioned. Suitable secondary surfactants are descnbed in detail m the copendmg provisional patent application of Chandπka Kastun et al., entitled "Liquid Detergent Compositions Compπsing Polymeric Suds Enhancers", having P & G Case No. 6938P, application senal no. 60/066,344, incorporated above.

Diammes - Diammes used herein in detergent compositions in combination with detersive surfactants at levels and ratios (discussed in further detail below) which are effective for achieving at least a directional improvement in cleaning performance. In the context of a hand dishwashing composition, such "usage levels" can vary depending not only on the type and seventy of the soils and stains, but also on the wash water temperature, the volume of wash water and the length of time the dishware is contacted with the wash water.

Since the habits and practices of the users of detergent compositions show considerable variation, the composition will preferably contain at least about 0.1%, more preferably at least about 0.2%, even more preferably, at least about 0.25%, even more preferably still, at least about 0.5% by weight of said composition of diamme. The composition will also preferably contain no more than about 15%, more preferably no more than about 10%, even more preferably, no more than about 6%, even more preferably, no more than about 5%, even more preferably still, no more than about 1.5% by weight of said composition of diamme. In one of its several aspects, this invention provides a means for enhancing the removal of greasy/oily soils by combining the specific diammes of this invention with surfactants. Greasy/oily "everyday" soils are a mixture of tnglycendes, lipids, complex polysacchaπdes, fatty acids, inorganic salts and proteinaceous matter. Thus diammes, in combination with amphotenc and anionic surfactants in the specific ratios discussed below, offer the benefit of improved grease and tough food cleaning which allows the elimination or reduction in the amount of divalent ions in the preferred embodiments of the present formula. This improved cleaning is a result of diamines' proclivity as a buffeπng agent to increase the alkalinity of the dishwashing composition. It is preferred that the diamines used in the present invention are substantially free from impunties. That is, by "substantially free" it is meant that the diamines are over 95% pure, i.e., preferably 97%, more preferably 99%, still more preferably 99.5%, free of impurities. Examples of impurities which may be present in commercially supplied diammes include 2-Methyl-l,3- diaminobutane and alkylhydropynmidine. Further, it is believed that the diamines should be free of oxidation reactants to avoid diamme degradation and ammonia formation.

As is discussed in greater detail below, making the compositions free of hydrogen peroxide is important when the compositions contain an enzyme. Even small amounts of hydrogen peroxide can cause problems with enzyme containing formulations. However, the diamme can react with any peroxide present and act as an enzyme stabilizer and prevent the hydrogen peroxide from reacting with the enzyme. The only draw back of this stabilization of the enzymes by the diamine is that the nitrogen compounds produced are believed to cause the malodors which can be present in diamme containing compositions. Having the diamine act as an enzyme stabilizer also prevents the diamme from providing the benefits to the composition for which it was originally put m to perform, namely, grease cleaning, sudsing, dissolution and low temperature stability. Therefore, it is preferred to minimize the amount of hydrogen peroxide present as an impunty in the inventive compositions either by using components which are substantially free of as an enzyme stabilizer, because of the possible generation of hydrogen peroxide and/or by using non-diamme antioxidants even though the diamme can act malodorous compounds and the reduction in the amount of diamine available present to perform its primary role.

Preferred organic diammes are those in which pK 1 and pK2 are m the range of about 8 0 to about 1 1.5, preferably in the range of about 8 4 to about 1 1, even more preferably from about 8.6 to about 10.75. Preferred materials for performance and supply considerations are 1,3- bιs(methylamιne)-cyclohexane (pKa=10 to 10.5), 1.3 propane diamine (pKl=10.5; pK2=8.8), 1 ,6 hexane diamme (pKl = l 1. pK2=10), 1,3 pentane diamine (Dytek EP) (pKl=10.5; pK2=8.9), 2-methyl 1.5 pentane diamine (Dytek A) (pK 1 = 1 1.2; pK2=10.0). Other preferred matenals are the primary/primary diamines with alkylene spacers ranging from C4 to C8. In general, it is believed that primary diamines are preferred over secondary and tertiary diamines. Definition of pKl and pK2 - As used herein, "pKal" and "pKa2" are quantities of a type collectively known to those skilled in the art as "pKa" pKa is used herein m the same manner as is commonly known to people skilled in the art of chemistry. Values referenced herein can be obtained from literature, such as from "Critical Stability Constants. Volume 2, Amines" by Smith and Martel, Plenum Press, NY and London, 1975. Additional information on pKa's can be obtained from relevant company literature, such as information supplied by Dupont, a supplier of diamines.

As a working definition herein, the pKa of the diammes is specified in an all-aqueous solution at 25°C and for an ionic strength between 0.1 to 0.5 M. The pKa is an equihbnum constant which can change with temperature and ionic strength; thus, values reported in the literature are sometimes not in agreement depending on the measurement method and conditions To eliminate ambiguity, the relevant conditions and/or references used for pKa's of this invention are as defined herein or in "Critical Stability Constants: Volume 2, Amines". One typical method of measurement is the potentiometπc titration of the acid with sodium hydroxide and determination of the pKa by suitable methods as descnbed and referenced in "The Chemist's Ready Reference Handbook" by Shugar and Dean, McGraw Hill, NY, 1990.

It has been determined that substituents and structural modifications that lower pKl and pK2 to below about 8.0 are undesirable and cause losses m performance. This can include substitutions that lead to ethoxylated diammes, hydroxy ethyl substituted diammes, diamines with oxygen in the beta (and less so gamma) position to the nitrogen in the spacer group (e.g., Jeffamine EDR 148). In addition, matenals based on ethylene diamme are unsuitable. The diammes useful herein can be defined by the following structure:

wherein R2.5 are independently selected from H, methyl, -CH3CH2, and ethylene oxides; C_x and C_v are independently selected from methylene groups or branched alkyl groups where x+y is from about 3 to about 6; and A is optionally present and is selected from electron donating or withdrawing moieties chosen to adjust the diamine pKa's to the desired range If A is present, then x and y must both be 1 or greater.

Specific diamines suitable for use in the present invention are discussed in greater detail in U S. Pat No 5,990,065, to Vinson et al., issued Nov. 23, 1999, which is hereby incorporated by reference.

Ratio of anionic to amphotenc to diamine - In a preferred embodiment of the present invention, the LDL compositions contain anionic surfactant, amphotenc surfactants, and diamine in a ratio of anionic: amphotenc: diamine from about 100 40: 1 to about 9:0.5: 1 , by mole, preferably the ratio of the anionic: amphotenc: diamme is from about 27-8.1 to about 11.3: 1, by mole. It has been found that detergent compositions containing anionic surfactant, amphotenc surfactant and diamine m this specific ratio range provide improved low temperature stability, deliver better grease removal and tough food cleaning benefits as well as improved hard water cleaning.

Calcium Or Magnesium Ions - The presence of calcium and/or magnesium (divalent) ions improves the cleaning of greasy soils for vanous compositions, i.e. compositions containing alkyl ethoxy carboxylates and/or polyhydroxy fatty acid amide. This is especially true when the compositions are used in softened water that contains few divalent ions. It is believed that calcium and or magnesium ions increase the packing of the surfactants at the oil/water interface, thereby reducing interfacial tension and improving grease cleaning. Compositions of the invention hereof containing magnesium and/or calcium ions exhibit good grease removal, manifest mildness to the skin, and provide good storage stability.

Preferably, the magnesium or calcium ions are added as a hydroxide, chlonde, acetate, formate, oxide or nitrate salt to the compositions of the present invention.

The amount of calcium or magnesium ions present in compositions of the invention will be dependent upon the amount of total surfactant present therein, including the amount of alkyl ethoxy carboxylates and polyhydroxy fatty acid amide. When calcium ions are present in the compositions of this invention, the molar ratio of calcium ions to total anionic surfactant is from about 0.25: 1 to about 2:1 for compositions of the invention.

Formulating such divalent ion-containing compositions in alkaline pH matnces may be difficult due to the incompatibility of the divalent ions, particularly magnesium, with hydroxide ions. When both divalent ions and alkaline pH are combined with the surfactant mixture of this invention, grease cleaning is achieved that is superior to that obtained by either alkaline pH or divalent ions alone. Yet, during storage, the stability of these compositions becomes poor due to the formation of hydroxide precipitates Therefore, chelating agents discussed herein below may also be necessary.

The ions are present in the compositions hereof at an active level of from about 0.1% to 4%, preferably from about 0.3% to 3.5%. more preferably from about 0.5% to 1%, by weight Although either species of divalent ion provides benefits when included in a detergent composition, preferably the detergent compositions of the present invention contain no calcium ions.

Solvents - The present liquid detergent compositions contain either diols or polymeπc glycols or a mixture of both diols and polymeric glycols (polymeric glycols are composed of ethylene oxide (EO) and propylene oxide (PO) groups). In addition to diols and polymeric glycols, a variety of other water-miscible liquids such as lower alkanols, diols, other polyols, ethers, amines, and the like may be used in the present invention. Particularly preferred are the C1-C4 alkanols. Suitable solvents are discussed m greater detail in the provisional patent application of Clarke et al., entitled "Diols and Polymeric Glycols for Improved Dishwashing Detergent Compositions", having P & G Case No. 7408 provisional serial no. 60/119,044, filed on February 8, 1999, which is hereby incorporated by reference.

When present the composition will preferably contain at least about 0.01%, more preferably at least about 0.5%, even more preferably still, at least about 1% by weight of the composition of solvent. The composition will also preferably contain no more than about 20%, more preferably no more than about 10%, even more preferably, no more than about 8% by weight of the composition of solvent.

Suds Booster - Another component which may be included in the composition of this invention is a suds stabilizing surfactant (suds booster) at a level of at least about 0.5%, preferably at least about 2%, more preferably at least about 5%. The composition will also contain no more than about 20%, preferably no more than about 15%, more preferably, no more than about 10% of said suds booster.

Suds stabilizing surfactants operable m the instant composition are: sultames, complex betaines, betaines, ethylene oxide condensates, fatty acid amides, amme oxide semi-polar noniomcs, and cationic surfactants. Also suitable as suds boosters are the polymeπc suds stabilizers disclosed in the provisional application of Clarke et al., entitled "Diols and Polymeπc Glycols for Improved Dishwashing Detergent Compositions", having P & G Case No. 7408 provisional serial no. 60/119,044, filed on February 8, 1999, which is hereby incorporated by reference. Builder (Chelants) - The compositions according to the present invention may further comprise builders. A general description of builder materials is contained in U S. Pat. No 5,990,065, to Vinson et al , issued Nov. 23, 1999, which is hereby incorporated by reference. If detergency builder salts are included, they will be included in amounts of from 0.5 % to 50 % by weight of the composition preferably from 5% to 30% and most usually from 5% to 25% by weight.

Other Ingredients - The detergent compositions will further preferably compnse one or more detersive adjuncts selected from the following: soil release polymers, polymenc dispersants, polysacchaπdes, abrasives, bacteπcides and other antimicrobials, tarnish inhibitors, builders, enzymes, dyes, buffers, antifungal or mildew control agents, insect repellents, perfumes, hydrotropes, thickeners, processing aids, bπghteners, anti-corrosive aids, stabilizers antioxidants and chelants A wide vaπety of other ingredients useful in detergent compositions can be included in the compositions herein, including other active ingredients, earners, hydrotropes, antioxidants, processing aids, dyes or pigments, solvents for liquid formulations, solid fillers for bar compositions, etc. If high sudsing is desired, suds boosters such as the Ci ø-Ci g alkanolamides can be incorporated into the compositions, typically at 1%-10% levels. The C I -

C14 monoethanol and diethanol amides illustrate a typical class of such suds boosters. Use of such suds boosters with high sudsing adjunct surfactants such as the amine oxides, betaines and sultaines noted above is also advantageous. Composition Form - The present liquid dishwashing detergent compositions may, optionally, be in the form of either a microemulsion or a bicontinuous microemulsion. By "microemulsion" or "conventional microemulsion" it is meant a thermodynamically stable mixture of oil and water in which a discontinuous domain is suspended in a continuous domain. The discontmous domain is in the form of sphencal droplets having radii of between 100 and 1000 A. When the discontinuous domain is oil and the continuous domain is water, it is an oil- m-water microemulsion. When the discontinuous domain is water and the continuous domain is oil, it is a water-m-oil microemulsion. See Surfactant Science Series, Volume 6 Emulsions and Emulsion Technology Part 1 (edited by Kenneth J. Lissant), p. 127. Marcel Dekker, New York (1974); Surfactant Science Series, Volume 66 Industrial Applications of Emulsions (edited by Conxita Solans et al.), p. 2. Marcel Dekker, New York ( 1997).

By "bicontinuous microemulsion" it is meant a thermodynamically stable mixture of oil and water wherein two continuous, interconnecting and separate domains, separated by a surfactant interface, are present rather than there being both a continuous and a discontinuous domain. A bicontinuous microemulsion is classified as a Winsor Type HI microemulsion P A Wmsor, Chem Rev 68, p 3-6 (1968), Surfactant Science Series, Volume 6 Emulsions and Emulsion Technology Part 1 (edited by Kenneth J Lissant), p. 191-92 Marcel Dekker, New York (1997) Surfactant Science Series, Volume 66 Industrial Applications of Emulsions (edited by Conxita Solans et al ), p. 158, Marcel Dekker, New York (1997).

When the detergent compositions are present in the form of a microemulsion or bicontinuous microemulsion, they will comprise (in addition to a selection of the ingredients described above): (a) a microemulsion-forming solvent; (b) a liquid hydrocarbon component; and (c) an aqueous liquid carrier. Suitable examples of each of these components as well as overwell formulation directions are discussed in the provisional patent application of Mark L. Kacher et al., entitled "Light Duty Liquid Dishwashing Compositions in the Form of Microemulsions", filed on April 8, 1999, having serial no. 60/128,351 and P&G Case No. 7504P, which is hereby incorporated by reference.

The following examples are illustrative of the present invention, but are not meant to limit or otherwise define its scope. All parts, percentages and ratios used herein are expressed as percent weight unless otherwise specified.

The following examples are illustrative of the present invention, but are not meant to limit or otherwise define its scope. All parts, percentages and ratios used herein are expressed as percent weight of the composition unless otherwise specified.

TABLE I A light-duty liquid dishwashing detergent formula having the following composition is prepared:

Example 1 Example 2 Example 3 Example 4 Example 5

AES¹ 27.0 26.0 20.0 26.0 20

Amine oxide² 6.5 7.0 4.0 - 6.0

Noniomc³ 2.4 3.0 2.0 3.5 3.0

Diamme⁴ 0.6 1.0 0.5 - -

Suds boosting 0.8 1.0 0.5 - 0.7 polymer⁵

Polypropylene 1.4 1.5 1.0 - 10.0 glycol

Ethanol 6.0 5.8 2.0 5.6 Amylase 0.002 0.005 0.0005 0.002 0.001

NaOH to pH 8.5 to pH 9.5 to pH 9.0 to pH 9.0 to pH 8.5

Limonene _. . . _. g o

Water and Balance Balance Balance Balance Balance Misc.

1 : C₁₂-₁₃ alkyl ethoxy sulfonate containing an average of 0.6 ethoxy groups. 2: C₁₂-C₁₄ Amme oxide.

3: Noniomc may be either C,ι Alkyl ethoxylated surfactant containing 9 ethoxy groups or Cι₀ Alkyl ethoxylated surfactant containing 8 ethoxy groups.

4: 1,3 bιs(methylamιne)-cyclohexane

5: Polymer is (N,N-dιmethylamιno)ethyl methacrylate homopolymer

Claims

WHAT IS CLAIMED IS:

1 A method for cleaning a substrate in a manual dishwashing operation consisting essentially of the steps of

(a) contacting an absorbing liquid detergent device with neat liquid dishwashing detergent composition; and

(b) directly contacting the substrate with the absorbing liquid detergent device for a sufficient amount of time to provide effective cleaning benefits to the substrate; wherein the neat liquid dishwashing detergent composition is characteπzed by: (0 from 0.0001% to 5%, of an amylase enzyme; and (n) at least 0.5% of a suds booster.

2. A method according to claim 1 wherein before step (a) or step (b) the substrate is contacted with a sufficient amount of water for a sufficient amount of time to hydrate the soil material adhered to the surface of the substrate.

3. A method according to any of claims 1-2 wherein the amylase enzyme has a specific activity at least 25% higher than the specific activity of Termamyla at a temperature range of 25°C to 55°C and at a pH value in the range of 8 to 10, measured by the Phadebasa a-amylase activity assay.

4. A method according to any of claims 1-3 wherein the liquid dishwashing detergent composition is further characteπzed by an enzyme selected from the group consisting of cellulases, hemicellulases, peroxidases, proteases, gluco-amylases, lipases, cutinases, pectmases, xylanases, reductases, oxidases, phenoloxidases, hpoxygenases, hgnmases, pullulanases, tannases, pentosanases, malanases, β-glucanases, arabmosidases and mixtures thereof.

5. A method according to any of claims 1-4 wherein the sufficient time is from 1 to 10 seconds.

6. A method according to any of claims 1-5 wherein the absorbing liquid detergent device is moistened with water.

7. A method according to any of claims 1-6 wherein the neat liquid dishwashing detergent composition is applied to the substrate with no more than 90% dilution with water.

8. A method according to any of claims 1-7 wherein the neat liquid dishwashing detergent composition is applied to the substrate with no more than 50% dilution with water.

9. A method according to any of claims 1-8 wherein the neat liquid dishwashing detergent composition is applied to the substrate with no more than 25% dilution with water.

10. A method according to any of claims 1-9 wherein step (b) is accompanied by a concurrent scrubbing of the article or substrate surface.

H \EPOCLAIMS\7941F-epo lsp