WO2001044429A1

WO2001044429A1 - Household cleaning products

Info

Publication number: WO2001044429A1
Application number: PCT/EP2000/012398
Authority: WO
Inventors: Jacqueline Mcinnes; David William Thornthwaite
Original assignee: Unilever N.V.; Unilever Plc; Hindustan Lever Ltd
Priority date: 1999-12-16
Filing date: 2000-12-06
Publication date: 2001-06-21
Also published as: AU2006701A

Abstract

A household cleaning product that comprises a hypohalite or a source thereof and a promoter selected from one or more of compounds containing a cyclic N-oxide group and compounds containing a cyclic P-oxide group.

Description

HOUSEHOLD CLEANING PRODUCTS

Field of the Invention

The present invention relates to liquid household cleaning products containing a hypochlorite bleach.

Background to the Invention

It is well known to use hypochlorite bleaches m household hard surface cleaning compositions, for example as kitchen surface cleaners typically containing 0.1-1.5% by weight of sodium hypochlorite at a pH of approximately 11,5-13,0, or at higher levels, e.g. up to 3% by weight of hypochlorite for mould removal. However, there remains a need to provide a household cleaning composition based on a hypochlorite which can exert more potent bleaching and/or bactericidal action than the conventional hypochlorite kind of product. Thereby, the amount of hypochlorite can be reduced, for improved safety and lower acrid smell, etc.

In WO 97/45523 a process for cleaning filters used in the production of foodstuffs is disclosed involving treating the filters with hypohalite in combination with certain saturated cyclic mtroxyl compounds such as 2,2,6,6- tetramethylpipeπdme-N-oxyl (TEMPO) and derivatives with the same carbon skeleton. These compounds are stable free radicals of the type also known as nitroxides.

It is also well known m the art to combine hypochlorite with various detergent surfactants in order to get a thickened hypochlorite solution or to improve its wetting properties. Mine oxide surfactants are often used for this purpose. Such amme oxide surfactants comprise at least one long chain alkyl groups and at least one C1-C3 alkyl group. Examples of such compositions are disclosed e.g. in GB 2 185 037. A special case is disclosed m GB 1 346 238 m which a cyclic amme oxide surfactant is used which contains a perfluoroalkyloxy chain of at least five carbon atoms .

The present invention provides improved hypochlorite based household cleaning products comprising hypochlorite or source thereof together with a promoter (as hereinafter defined) which potentiates the activity of the hypochlorite and which is selected from one or more cyclic oxides of nitrogen or cyclic oxides of phosphorus.

Cyclic N-oxides have been used as dye transfer inhibitors m laundry wash compositions containing oxygen bleaches , see EP-A-0 596 184 and US-A-5 574 003.

Definition of the Invention

The present invention now provides a household cleaning product comprising a hypohalite or a source thereof and a promoter selected from one or more of compounds containing a cyclic N-oxide group and compounds containing a cyclic P- oxide group.

Systems according to the invention are applicable for use in a range of products where relatively high concentrations of hypochlorite bleach are currently required to achieve acceptable cleaning and hygiene performance. Specific product types include: mould removers, wc and kitchen cleaners .

Detailed Description of the Invention

The hypohalite (or source thereof) and the promoter may be provided in any convenient product form, for example as a granular solid, or a compressed solid such as a tablet or block, or in liquid form, preferably in aqueous liquid form.

In the case of solid formulations which are granular, the hypohalite, or source thereof, may be formulated in the same granules as the promoter. Alternatively, the hypohalite or hypohalite source may be provided in one granule and the promoter in a second co-granule. For tablets or blocks both hypohalite (or source thereof) and promoter may be intermixed in a unitary tablet or block or may respectively be provided in separate parts or layers of the tablet or block. For consumer appeal, these parts or layers may be coloured differently from each other, for example by incorporation of one or more pigments or dyes, or by surface printing.

In the case of (preferably aqueous) liquid formulations, the hypohalite or hypohalite source may be incorporated in the same liquid, e.g. as an aqueous solution of both. However, depending on the concentration, pH and optional other components of the formulation, the composition may require a stabiliser for the hypohalite, of the kind which will be well known to those skilled in the art. Alternatively, such liquid formulations may be provided as a dual container delivery system comprising a first container containing a first aqueous solution comprising the hypohalite or a source thereof, a second container containing a second aqueous solution comprising the promoter, and delivery means for delivering the first and second solutions to a surface such that the hypohalite and promoter are admixed just before or upon impacting the surface.

This dual container kind of embodiment could be realised merely by providing the two solutions m respective separate containers. The consumer could then apply each to the surface, either sequentially or simultaneously.

However, it is more convenient to provide the products in a dual-compartment container in which the aqueous solutions are stored in separate compartments. The delivery means then allows them to be delivered to the surface as they are exiting the delivery means and/or in mid-air as they are directed to the surface and/or on the surface itself. Preferably, they are delivered to be mixed in approximately equal volumes, i.e. typically from 0.5 : 1 v/v to 1 : 0.5 v/v.

A particularly preferred delivery means, either from a single compartment or a dual compartment container, is a trigger spray head. In the case of a dual compartment system, this will preferably have two siphon tubes, respectively leading into each compartment and either a single nozzle with a mixing chamber or two separate nozzles substantially adjacent to each other. If desired, a dispensing nozzle or nozzles configured to promote foaming may be used.

The Hypohalite

The hypohalite or hypohalite source may be a simple hypochlorite salt such as those of the alkali or alkaline earth metals or a compound which produces hypochlorite on hydrolysis, such as organic N-chloro compounds.

The hypochlorite or hypochlorite source is preferably present at about from 0.01% to 10%, more preferably from 0.1% to 2%, still more preferably from 0.25% to 1.0% by weight of the total product.

The hypohalite may also be hypobromite, which is conveniently provided in situ from a bromide salt and a suitable strong oxidant such as hychlorite..

The Promoter

The promoter must be of a type and in amount which potentiates the bleaching and/or bactericidal and/or anti- fungal activity of the hypochlorite. Preferably, it is a compound of formula (I) :-

wherein :

G is a heteroato selected from nitrogen and phosphorus;

A¹ is an aliphatic or aromatic ring system containing from 4 to 6 carbon atoms in addition to the heteroatom G; n is at least 1 and represents the total number of R¹ substituents on the carbon atoms of ring A¹; - each R¹ group is the same or different, at least one R¹ group being selected from straight or branched hydrophobic moieties comprising a hydrocarbon group of at least 3 carbon atoms and tertiary amides of formula - CONR²R³ wherein R² and R³ are independently selected from d- ₆ alkyl groups, phenyl, benzyl and C₅-₇ cycloalkyl groups, or at least two R¹ groups together represent an aliphatic or aromatic bridging moiety which is hydrophobic and forms a ring fused with the ring A¹ , any other R¹ groups being chosen from small moieties such as Cι-₄ alkyl groups, -OH, nitro, carboxyl groups and the like.

In formula (I), preferably, the ring system A¹ is aromatic More preferably it is pyridine N-oxide, i.e.

In one preferred embodiment one of R¹ is straight or branched C-10 alkyl or phenyl-C_ι-₄-alkyl, in which case more 5 preferably n is 1. In another preferred embodiment n is 2 and the two R¹ groups together form a carbocyclic ring ring fused with the ring A¹, more preferably the two R¹ groups form a benzene ring fused with R¹.

10 When n is 1 and A is pyridine N-oxide, R¹ is a substituent in the 2, 3, or 4 position. When n is 2 and A is pyridine N-oxide, the R¹ groups bridge the 2 and 3 or the 3 and 4 positions .

15 For the purposes of this invention the terms "hydrocarbon" and "alkyl" do not encompass "perfluoro-hydrocarbon" and "perfluoro-alkyl" respectively.

The promoter is preferably present at about from 0.01% to 20 10%, more preferably from 0.1% to 2.0%, especially from 0.25% - 1% by weight of the total composition. The pH of the product is preferably from 8 to 13, more preferably from 9 to 13. The weight ratio of the hypochlorite or its precursor to the promoter is typically from 0.5 : 1 to 25 100 : 1, preferably at most 50 : 1.

The hypochlorite or its source is preferably present in alkaline solution, in order to minimise decomposition. In the case of dual-container liquid products, the pH of the first solution is preferably adjusted to a value such that on mixing the final pH of the formulation is optimised for the specific usage scenario. It is important that the mixing process be carefully controlled so that the pH of the final mixed solution is constrained not to fall below a value of 8. However, higher pH values are preferred (see further below) . In case of incomplete mixing lower pH values could result in localised areas of very low pH with the consequent risk of generating toxic halogen gas.

Surfactants :

The products according to the invention optionally may comprise detergent actives (surfactants) .

Surfactants may be chosen from a wide range of anionic, nonionic, cationic, amphoteric or zwitterionic surfactants well known in the art.

Suitable anionic surfactants are e.g. water-soluble salts, particularly alkali metal, alkaline earth metal and ammonium salts, of organic sulphate esters and sulphonic acids having in the molecular structure a C₈-C₂2 alkyl radical or a C10-C22 alkaryl radical. Examples of such anionic surfactants are alcohol sulphate salts, especially those obtained from the fatty alcohols derived from the glycerides of tallow or coconut oil; alkyl-benzene sulphonates such as those having a C_.-Cn. Examples of such anionic detergents are alcohol sulphate alkyl group attached to the benzene ring; secondary alkanesulphonates; sodium alkyl glyceryl ether sulphates, especially those ethers of the fatty alcohols derived from tallow and coconut oil; sodium fatty acid monoglyceride sulphates, especially those derived from coconut fatty acids; salts of 1-6 EO ethoxylated fatty alcohol sulphates; salts of 1-8 EO ethoxylated alkylphenol sulphates in which the alkyl radicals contain 4-14 C-atoms; the reaction product of fatty acids esterified with isethionic acid and neutralised with sodium hydroxide.

The preferred water-soluble synthetic anionic surfactants are the alkyl benzene sulphonates, the olefin sulphonates, the alkyl sulphates, and the higher fatty acid monoglyceride sulphates and fatty acid soaps.

A special class of anionic surfactants which may be used in the cleaning products according to the invention are hydrotropes which are known in the art specifically for their thickening or liquid structuring capabilities. Well known examples of such compounds are the alkali metal salts of toluene-, xylene- and cumene-sulphonic acid.

Suitable nonionic surfactants can be broadly described as compounds produced by the condensation of alkylene oxide groups, which are hydrophilic in nature, with an organic hydrophobic compound which may be aliphatic or alkylaromatic in nature. The length of the hydrophilic or polyoxyalkylene radical which is attached to any particular hydrophobic group can be readily adjusted to yield a water-soluble or water dispersible compound having the desired balance between hydrophilic and hydrophobic elements.

Particular examples include the condensation product of straight chain or branched chain aliphatic alcohols having 8- 22 C-atoms with ethylene oxide, such as coconut oil fatty alcohol/ethylene oxide condensates having from 2 to 15 moles of ethylene oxide per mole of coconut alcohol; condensates of alkylphenols whose alkyl group contains 6-16 C-atoms with 2 to 25 moles of ethylene oxide per mole of alkylphenol; condensates of the reaction product of ethylenediamine and propylene oxide with ethylene oxide, the condensates containing from 40 to 80% of ethyleneoxy groups by weight and having a molecular weight of from 5,000 to 11,000. The ethylenoxide condensates may be end-capped by replacing the terminal hydroxy group with a C1-C6 alkyl group.

Other examples of nonionic surfactants are: tertiary amine oxides of general structure RRRNO, where one R is a C₈-C₂₂ alkyl group (preferably C₈-Cι₈) and the other Rs are each C_-C₅ (preferably Cι-C₃) alkyl or hydroxyalkyl groups, for instance dimethyldodecylamine oxide; tertiary phosphine oxides of structure RRRPO, where one R is a C₈-C₂₂ alkyl group (preferably C₈-Cι₈) and the other Rs are each C1-C₅ (preferably C1-C3) alkyl or hydroxyalkyl groups, for instance dimethyl- dodecylphosphine oxide; dialkyl sulphoxides of structure RRSO where one R is a Cι_-C_₈ alkyl group and the other is methyl or ethyl, for instance methyltetradecyl sulphoxide; fatty acid alkylolamides; alkylene oxide condensates of fatty acid alkylolamides and alkyl mercaptans . Amine oxides are especially preferred because they blend very well with inorganic electrolytes and show good stability to hypochlorite bleach.

Suitable amphoteric surfactants are derivatives of aliphatic secondary and tertiary amines containing a C₈-Cι₈ alkyl group and an aliphatic group substituted by an anionic water- solubilising group, for instance sodium 3-dodecylamino- propionate, sodium 3-dodecylammopropane sulphonate and sodium N-2-hydroxydodecyl-N-methyl taurate .

Suitable cationic surfactants are quaternary ammonium salts having at least one C₈-C₂2 aliphatic or alkyl-aromatic group, e.g. dodecyl-trimethylammonium bromide or chloride, cetyltrimethyl-ammonium bromide or chloride, didecyl- di ethyl-ammonium bromide or chloride, octyl-benzyldimethyl- ammonium bromide or chloride, dodecyl- benzyldimethyl- ammonium bromide or chloride and (higher alkyl) - benzyldimethyl-ammonium bromide or chloride. Many quaternary ammonium salts have antimicrobial properties and their use cleaning compositions according to the invention leads to products having exceptionally effective disinfection properties against a wide range of micro-organisms. They are used in the cleaning compositions according to the invention in an amount of 0-10%, preferably 0.1-8%, more preferably 0.5-6%

Suitable zwitterionic surfactants are derivatives of aliphatic quaternary ammonium, sulphonium and phosphonium compounds having a C₈-Cι₈ aliphatic group and an aliphatic group substituted by an anionic water-solubilismg group, for instance 3- (N,N-dimethyl-N-hexadecylammonium) propane-1- sulphonate betaine, 3- (dodecyl-methyl-sulphonium) -propane-1- sulphonate betaine and 3- (cetylmethyl-phosphonium) -ethane- sulphonate betaine.

Further examples of suitable surfactants are given the well-known textbooks "Surface Active Agents", Volume I by Schwartz and Perry and "Surface Active Agents and Detergents", Volume II by Schwartz, Perry and Birch. Detergent surfactants often play an important role in thickening systems. Apart from that they are preferably added also for their wetting properties on hard surfaces and for their cleaning properties. Thus, preferably surfactants are present even if a non-surfactant thickening system is used. If not required for thickening, the total surfactants content is preferably between 0.1 and 20%, more preferably between 0.5 and 10%, most preferably at most 7%. If part of the thickening system the minimum total amount of surfactant will be at least 0.5%, preferably at least

1 &

Electrolytes, particularly inorganic salts, are part of many thickening systems. Suitable salts are alkali metal carbonates, sulphates and halogenides. Electrolytes are used in an amount of 0-20%, preferably 0-15%, more preferably 0- 10%.

The cleaning products according to the invention may also usefully contain a sequestering agent suitable for binding Ca ions. Suitable sequestering agents for this purpose are well known in the art and include compounds such as: alkali metal tripolyphosphate, pyrophosphate and ortho- phosphate, sodium nitrilotriacetic acid salt, sodium methylglycine-diacetic acid salt, alkali metal citrate, carboxymethyl malonate, carboxymethyloxysuccinate, tartrate, mono- and di-succinate and oxydisuccinate.

Many thickening systems have been used in thickened hypochlorite bleach compositions. Such systems often consist of two or more different detergent surfactants, or of one or more such surfactants in combination with an electrolyte such as an inorganic salt. Many thickening systems comprise as one of their components tertiary amine oxides containing one long alkyl chain e.g. having 8-22 C - atoms and two shorter alkyl chains e.g. having 1-5 C-atoms, often in combination with an anionic surfactant.

Examples of such thickening systems are described in EP-A- 079697, EP-A-110544, EP-A-137551, EP-A-145084, EP-A-244611, EP-A-635568, WO95/08611, DE-A-19621048 and the literature cited in these patent applications.

Other suitable thickening systems comprise polymeric substances which in solution thicken in response to an increase in pH or electrolyte concentration. Examples thereof are polymers of acrylic acid known for their thickening properties such as those sold under the trademark Acusol" .

Alkalinity

Preferably, the product composition, or in the case of dual-container systems, the first (hypochlorite or hypochlorite precursor) aqueous solution, also contains a source of alkalinity which keeps its pH at or above 11.5, not only during production of the product but also during storage. For the purposes of this invention a source of alkalinity is defined as a mixture of ingredients which is able to keep the pH at or above the required level. In the case of dual-container systems, preferably the pH of the first (hypochlorite or hypochlorite precursor) should be kept at or above 12, more preferably at or above 12.5. For single compositions in liquid form, the pH will preferably be from 8 to 13, more preferably from 9-13. Suitable sources of alkalinity are known m the art and are generally made up of highly alkaline compounds such as alkali metal hydroxides and alkali metal salts of weak acids such as alkalimetal carbonates and silicates. Particularly suitable alkali sources comprise mixtures of alkali metal hydroxide and alkali metal silicate such as sodium silicate wherein the Na₂0/Sι0₂ ratio is 1:1 or above, preferably 1.5:1 or above. Examples thereof comprise 0.2-0.6% of NaOH and a suitable amount of alkaline Na silicate (e.g. 0.1-3%wt).

Other Optional Components

The composition may also contain surfactants, polymers and other formulation components such as a perfume, colourant and foam control agents. In the case of single container systems these components, as well as the other components m the composition should be sufficiently stable to hypochlorite at the pH of the composition to ensure adequate storage stability. In the case of dual-container systems, some or all of these additional components can be stored separately from hypochlorite, i.e. together with the other liquid, allowing use of formulation ingredients that do not have long term stability m hypochlorite solution and are therefore not used conventional single compartment hypochlorite bleach formulations. Examples

Examples 1 - 6

The following specific examples of N-oxide activators were examined:

The data shown below relates to usage of N- oxide/hypochlorite systems specifically on oily soils Removal of a light oily kitchen soil : ^xcurcumin/oil' on Decamel

^λCurcumin/oil' is a light model kitchen soil comprising sunflower oil and curcumin (the principal pigment in curry powder) .

Decamel tiles (3 x 3 square inches) were cleaned using isopropanol and dried before application of the soil. Care was taken not to contaminate the cleaned surface, especially by touch as otherwise red streaking occurs when the soil is applied.

The soil was prepared by adding 0.5g of powdered curcumin pigment to 9.5g of commercial sunflower oil and stirring the mixture for 5 minutes. 90g of absolute RR ethanol was then slowly added to the mixture and the resulting solution stirred for at least 10 minutes prior to application to the substrate .

The curcumin/oil/ethanol solution was sprayed onto the vertical Decamel tiles using a C0BALT' gravity feed spray gun (ex. SIP, 500ml pot capacity, 1.5mm nozzle) attached to a compressor. Care was taken to ensure even soil coverage and it is important that the curcumin/oil solution is constantly swirled whilst in the spray gun ^λcup' , in order to maintain a homogeneous solution The soiled tiles were allowed to stand for a minimum of 1 hour allowing evaporation of the ethanol solvent, producing a slightly tacky yellow coloured oil film. The colour of treated tiles fades over time (due to photobleaching) and soiled tiles were therefore prepared on the same day as they were used. A circular glass ring (diameter 5cm) was placed over the centre of the soiled tile and 5ml of the cleaning solution was pipetted into the enclosed area. The glass template was pressed flat onto the tile surface for 30 seconds (preventing leakage of the cleaning solution) after which time the template was removed and the tile immediately rinsed under demineralised water and then allowed to dry for up to 30 minutes. At least two replicate soiled tiles were treated with each bleach system. The level of soil removal was visually assessed by trained panellists using a half integer sale ringing from 0 (no soil removal) to 5 (complete soil removal) . The resulting data were statistically analysed to yield mean soil removal.

Tables 1A and IB : Removal of curcumin/oil' soil from Decamel sheeting by various systems (30 seconds contact time, ambient temperature, pH 10)

Table 1A

All systems were examined in the absence of surfactant Table IB

All systems were examined in the absence of surfactant

The results shown in Tables 1A and IB establish a higher degree of soil removal for compositions of the invention with N-oxides (l)-(4) of the invention in comparison with the controls without any N-oxide or those with N-oxides (5) and (6), which are not within the scope of the invention.

Bactericidal Testing of Formulations

The test was designed to reflect the European Suspension Test protocol (European Standard EN1276) . The bacterial test suspension contained between 1.5 and 5.0 x 10⁸ cfu.mL^"1.

Testing was performed under conditions of heavy soil. A solution of 3% bovine albumin is prepared. The test formulation is pre-diluted to the relevant concentration in sterile Water of Standard Hardness (24° French Hard) . The presence of the bacterial test solution and interfering substance result in a further 1 : 1.25 dilution of the formulation in the test procedure.

Test Procedure : A volume of the interfering substance was pipetted into a sterile container and an equal volume of the bacterial test suspension was added and contents of the tube were mixed. The bacteria and soil were allowed a contact time of 2 min ± 10s. At the end of this contact time, a volume of the diluted formulation was added to produce an overall 1 : 10 dilution of both the bacterial test suspension and interfering substance and the contents of the tube were mixed again. The formulation was allowed a bactericidal contact time of 5 min ± 10s.

At the end of the contact time an aliquot was removed and diluted 1 : 10 into a sterile container containing a suitable chemical quenching solution. The contents were mixed thoroughly and left for a contact time of 5 min ± 1 minute. The dilution process was repeated a further five times into a suitable diluent to produce a series of six dilutions of the bactericidal stage ranging from 10^"1 to 10^"6.

Total viable counts were enumerated by a suitable method and the reduction in numbers of viable cells elicited by the test formulation was calculated. Table 2: Log Reduction of E. coli tested against the oxide (1) (referered to above) with and without added NaOCl (0.3% BSA) - pH 8-9:

Overall 1 20 dilution from the test solution

Claims

1. A household cleaning product comprising a hypohalite or a source thereof and a potentiating effective amount of a promoter selected from one or more of compounds of formula (I ) : -

wherein:

G is a heteroatom selected from nitrogen and phosphorus;

A¹ is an aliphatic or aromatic ring system containing from 4 to 6 carbon atoms in addition to the heteroatom G; n is at least 1 and represents the total number of R¹ substituents on the carbon atoms of A¹; each R¹ group is the same or different, at least one R¹ group is selected from straight or branched hydrophobic moieties comprising a hydrocarbon group of at least 3 carbon atoms and tertiary amides of formula -CONR²R³ wherein R² and R³ are independently selected from Cχ-6 alkyl groups, phenyl, benzyl and C5-7 cycloalkyl groups, or at least two R¹ groups together represent an aliphatic or aromatic bridging moiety which is hydrophobic and forms a ring fused with the ring A¹ , any other R¹ groups being chosen from small moieties such as Cι-₄ alkyl groups, -OH, nitro, carboxyl groups and the like.

2. A product according to claim 1 wherein the ring system A¹ is aromatic.

3. A product according to claim 2 wherein the ring system is pyridine N-oxide.

4 A product according to claims 1-3 wherein one of R¹ is straight or branched C₄_ι_. alkyl or phenyl-Cχ-₄-alkyl .

5. A product according to claims 1-3 wherein n is 2 and the two R¹ groups together form a carbocyclic ring ring fused with the ring A¹.

6. A product according to claims 1-5 in the form of a granular, block or tabletted solid.

7. A product according to claims 1-5 in the form of a liquid formulation.

8. A product according to claim 7 comprising a dual container delivery system comprising a first container containing a first aqueous solution comprising the hypohalite or a source thereof, a second container containing a second aqueous solution comprising the promoter, and delivery means for delivering the first and second solutions to a surface such that the hypochlorite and promoter are admixed just before or upon impacting the surface

RECTIFIED SHEET (RULE 91) ISA / EP

9. A product according to claim 9, wherein the first and second containers respectively are in the form of first and second compartments of a dual-compartment container.

10. A product according to claims 7-9, wherein the delivery means is in the form of a trigger-spray head.

11. A product according to claims 1-10 wherein the hypohalite is hypochlorite.

12 A product according to any preceding claim, comprising from 0.01% to 10% by weight, preferably from 0.1% to 2.0%, more preferably from 0.25% to 1.0% by weight of the hypohalite or hypohalite source.

13. A product according to any preceding claim, wherein the weight ratio of the hypohalite or hypohalite source to the promoter is from 0.5 : 1 to 100 : 1.

14. A product according to any preceding claim in liquid form, wherein the pH of the product is from 8 to 13, preferably from 9 to 13.

RECTIFIED SHEET (RULE 91) ISA/EP