WO2003044150A1

WO2003044150A1 - Process for cleaning household surfaces

Info

Publication number: WO2003044150A1
Application number: PCT/EP2002/012862
Authority: WO
Inventors: Vijaya Milind Bargaje; Kripa Devagna Mody; Kenneth Leslie Rabone; Glyn Roberts; Martin Sharples
Original assignee: Unilever Plc; Unilever Nv; Hindustan Lever Limited
Priority date: 2001-11-22
Filing date: 2002-11-18
Publication date: 2003-05-30
Also published as: AU2002349036A1

Abstract

The invention provides a process of cleaning household surfaces comprising applying to the surface a temporary emulsion which is formed by the agitation of a composition comprising at least two immiscible liquids, the liquids having at least one liquid-liquid interface with an interfacial tension of at least 5 mN/m, and in which the concentration of the most polar liquid in the composition is from 10 to 90% by volume. The process is especially effective for the removal of particulate soil from household surfaces such as carpets and tiles.

Description

PROCESS FOR CLEANING HOUSEHOLD SURFACES

TECHNICAL FIELD

The invention relates to a method or a process of cleaning household surfaces which is especially suitable for the removal of particulate soil in the absence of, or at very much reduced levels of, conventional detergent surfactants.

BACKGROUND AND PRIOR ART

Household surfaces are prone to contamination with particulates, especially organic particulates .

Such contamination raises a host of problems ranging from risk of illness, infection and allergic reaction (e.g. from bacteria, viruses, house dust mites) to unsightly staining which is difficult to clean (e.g. from mould, mildew) . The problem of contamination is especially acute when the particulates are lodged in pores, crevices or other irregularities which frequently exist in typical household surfaces such as carpet pile, porcelain and tiling.

Conventionally, household surfaces are cleaned using water and a detergent composition comprising one or more surfactants. The surfactants facilitate the removal of soil from the surface by the reduction of interfacial tension.

The present inventors have now found that cleaning household surfaces with a composition comprising at least two immiscible liquids results in superior particulate removal as compared to conventional cleaning methods. Surprisingly, this effect is apparent without using, or using very much reduced levels of, conventional detergent surfactants.

SUMMARY OF THE INVENTION

The present invention provides a process of cleaning household surfaces comprising applying to the surface a temporary emulsion which is formed by the agitation of a composition comprising at least two immiscible liquids, the liquids having at least one liquid-liquid interface with an interfacial tension of at least 5 mN/m, and in which the concentration of the most polar liquid in the composition is from 10 to 90% by volume.

DETAILED DESCRIPTION OF THE INVENTION

By "household surfaces" is meant those surfaces which are found on typical household fixtures and fittings, and which are prone to contamination.

Examples include lavatory fixtures, lavatory appliances (toilets, bidets, shower stalls, bathtubs and bathing appliances) , wall and flooring surfaces (in particular tiled surfaces) , carpets, mattresses and other soft furnishings, and those surfaces associated with kitchen environments and other environments associated with food preparation (for example chopping boards, oven surfaces, sinks, washing-up bowls and other kitchen surfaces, and kitchen equipment such as crockery, cutlery, pots, pans and other food preparation utensils) . The process of the invention is particularly effective on tiled and carpeted household surfaces.

The process of the invention utilises a composition comprising at least two immiscible liquids with a high interfacial tension.

The interfacial tension (IFT) of at least one liquid-liquid interface in the composition is at least 5 mN/m, preferably at least 8 mN/m, and more preferably at least 10 mN/m. Suitably the interfacial tension is at least 15 mN/m, advantageously at least 20 mN/m and desirably at least 35 mN/m. Interfacial tension may be measured using various techniques, such as sessile drop, pendant drop, spinning drop, drop volume or Wilhelmy plate method. For the purposes of the present invention, interfacial tension is measured by the Wilhelmy plate method, using a Kruss Processor Tensiometer K12, at 25 °C.

For some systems, the interfacial tension may change whilst undergoing shearing forces typically encountered in a cleaning process. It is customary to refer to the interfacial tension under these conditions as a "dynamic interfacial tension" (DIFT) and may be measured by a maximum bubble pressure technique.

Liquids

The at least two immiscible liquids in the composition used in the process of the present invention may suitably be chosen from the following groups of more polar and less polar liquids respectively: More polar liquids that may be used include water, alcohols, ethers, glycol ethers, ketones, phenols, aldehydes, organic sulphur compounds, nitrogen-containing compounds such as nitrates or nitriles, and mixtures thereof.

Water is a preferred more polar liquid.

Less polar liquids which may be used include esters, hydrocarbons, paraffins, aromatic solvents, halogenated solvents, heterocyclic solvents, terpenes, mineral oils, silicone oils and mixtures thereof.

Preferably the less polar liquid is selected from hydrocarbons and halogenated solvents and mixtures thereof. Examples of suitable hydrocarbons include isoparaffins, petroleum ether, cyclohexane and mixtures thereof. Examples of suitable halogenated solvents include perchloroethylene and preferably fluorosolvents such as methoxy or ethoxy nonafluorobutane, and mixtures thereof.

Mixtures of any of the above liquids can be used, provided at least one liquid-liquid interface exists and the interfacial tension is at least 5 mN/m, preferably at least 10 mN/m.

The amount of the most polar liquid in the composition is from 10 to 90% by volume, preferably from 25 to 90%, more preferably from 40 to 90% and most preferably from 60 to 90%. It is especially preferred to match the densities of the at least two immiscible liquids in the composition, since this improves the stability of the temporary emulsion formed by agitation of the composition and thereby the cleaning performance in hand cleaning operations. Such density matching can be achieved by a judicious selection of liquids according to their intrinsic density measurements, or alternatively by adjustment of density by extrinsic methods - for example, where the more polar liquid is water, its density can be increased by the addition of an appropriate amount of electrolyte .

Optional Ingredients

It is possible to incorporate other optional ingredients which aid in cleaning performance and maintain the physical and chemical stability of the product.

Examples include: perfumes, colours and dyes, further hygiene agents, fluorescers, dye transfer inhibitors, polymers, foam-control agents, viscosity modifying agents and mixtures thereof .

In principle, limited amounts of surfactant may be present provided that the interfacial tension is not reduced below 5 mN/m, preferably not below 10 mN/m. However, the composition preferably comprises less than 2% by weight, more preferably less than 1% by weight surfactant, and is most preferably free of surfactant . In a preferred embodiment of the present invention, a fatty acid or fatty amine with a carbon chain length of C₁₂ to C2₂ maybe added to the composition. The fatty acids and fatty amines which may be used in the composition as optional ingredients may be selected from any one or more with carbon chain length ranging from C₁₂ to C₂₂ and preferably with a chain length of Cis to C₂₂ ■ It has been observed that the energy required for agitation may be reduced when fatty acid or amines are incorporated.

In another preferred embodiment of the present invention, salts may be added to the composition. The salts which may be used in the composition as optional ingredients are preferably mineral salts produced by the neutralisation of a mineral acid. Suitable salts include sodium chloride, potassium chloride, lithium chloride, sodium carbonate. Salts may be present at any suitable level up to and including the point where the liquids are saturated.

In another preferred embodiment of the present invention, builders may be added to the composition. The builders which may be used in the composition as optional ingredients are preferably inorganic. Suitable builders include, for example, ethylene diamine tetraacetate (EDTA) , diethylene triamine pentaacetate (DTPA) , sodium tripolyphosphate

(STPP) , alkali metal aluminosilicates (zeolites) , alkali metal carbonate, tetrasodium pyrophosphate (TSPP) , citrates, sodium nitrilotriacetate (NTA) , and combinations of these. Builders are suitably used in an amount ranging from 0.01 to 1% by weight. In a particularly preferred embodiment of the present invention, soil release polymers may be added to the composition. These are particularly valuable in enhancing cleaning of textile-based household surfaces such carpets. Soil release polymers are useful in releasing hydrophobic stains or particulates from textile fibres, and especially synthetics. Typical soil release polymers include nonionic or anionic polymers, and mixtures thereof. The predominant number of soil release polymers are polyesters based on terephthalic acid, polyalkylene glycols and monomer glycols. A suitable commercially available example is the polyester soil release polymer Navdeelose T (ex. Navdeelase Chemicals) .

Product Form and Packaging

The composition used in the process of the invention may suitably be supplied as a ready to use product packaged in a conventional plastics container. Agitation of the composition to form the temporary emulsion to be applied to the household surface may be provided by manual shaking of the container by the consumer prior to use .

Other methods of vigorous agitation known in the art may also be used in conjunction with the composition used in the process of the invention.

Suitably, the composition used in the process of the invention is packaged in a spray container. By "spray container" is meant a container which is equipped with a spray or pump mechanism. In this way, the required agitation of the composition inside the container is effected by the turbulent mixing and channelling of the composition through the spray nozzle or outlet as it is discharged onto the surface to be treated.

The spray or pump mechanism may be manually or electrically operated.

A typical manually operated spray container will generally include a cap which is in threaded engagement with threads on the top of the container. A suction tube extends through the cap to the bottom of the container. A spray or pump mechanism is attached to the suction tube and the contents are dispensed by either depressing a pump mechanism or squeezing a spray handle mechanism such as a trigger. The contents are discharged through a nozzle or outlet in a stream, drop or mist, depending upon the type of dispensing actuator .

A typical electrically operated spray container will comprise an electrically driven pump and a spray arm being either extended or extendible and having at least one dispensing opening. In operation, the composition is pumped by the electrically driven pump from the container, through the spray arm to the dispensing opening from which it is dispensed. Preferably the spray arm communicates with the container by means of a flexible connector. The spray arm may have one nozzle or multiple nozzles located along its length. Such an electrically operated spray container is particularly suitable for the treatment of large surface areas such as carpets and other floor coverings. Preferably, the composition used in the process of the invention may be used in conjunction with an automated cleaning apparatus suitable for large surface areas such as carpets and other floor coverings. Such an apparatus will typically incorporate a container adapted to house the composition used in the process of the invention, agitation means for producing the necessary agitation of the composition to form the temporary emulsion to be applied to the household surface, distribution means for application of the temporary emulsion so formed to the surface to be treated, and preferably suction means (e.g. vacuum aspiration) for physically removing the particulate soil which has been dislodged from the treated surface by the operation of the process of the invention.

The invention is further illustrated by the following non- limiting examples, in which parts and percentages are by weight unless otherwise stated.

EXAMPLES

PARTICULATE SOIL REMOVAL FROM CARPETS

Example 1

Method

Carpets (80:20 wool :polyamide) were soiled by spraying a dispersion (0.25%) of carbon black (Elftex 570 ex Cabot Carbon) in IMS to give a soil surface coverage of O.Ollg/cm^'

2

(16.5 g of dispersion applied to an area of 50 x 30 cm ) . Carpets were stored overnight at ambient conditions to ensure complete removal of the dispersion solvent. The soil was then manually worked into the pile using a stiff brush. The carpets were then cut into strips approx. 10 cm x 20 cm in size.

The average initial reflectance at 460 nm with contribution due to UV excluded (hereafter referred to as R460*) of the soiled carpet strips was obtained using a Macbeth Colour-eye 7000A reflectometer.

20 ml of a wash solution containing 0.05 grams of a detergent having the formulation given below in Table 1 was mixed thoroughly by hand in a 50 ml conical flask, and then the mixture was poured evenly onto the surface of a soiled carpet strip as prepared above . The strip was then brushed a total of 10 times using a nylon scrubber. This process was repeated on a second strip to endure reproducibility. Both strips were then allowed to air-dry and the final reflectance values for the swatches at R460* determined.

The change in reflectance dR was determined by subtracting the initial reflectance from the final reflectance for each strip, and the average change in reflectance (hereafter referred to as dR460*) for the two strips was calculated.

Table 1

Example 2

The method described above for Example 1 was repeated except that 0.2 g of Navdeelose T solution was added to the

20 mis wash solution in addition to the detergent described in Table 1 above.

Example 3

The method described above for Example 1 was repeated except that the wash solution was replaced with 20 mis of a 30:70

12 ) ( 3 ) (by weight) mixture of HFE 7100 and DF2000 . Example 4

The method described above for Example 1 was repeated except that the wash solution was replaced with 20 ml of water.

Example 5

The method described above for Example 1 was repeated except that the wash solution was replaced with 10 mis of water and

(2) 10 mis of a 30:70 (by weight) mixture of HFE 7100 and

DF2000⁽³⁾ .

Example 6

The method described above for Example 1 was repeated except that the wash solution was replaced with 10 mis of a 30:70

(2) (3)

(by weight) mixture of HFE 7100 and DF2000 together

with 10 mis of water into which 0.1 g of Navdeelose T had been pre-dissolved.

Results

The average change in reflectance (dR460*) for carpet strips treated as described for Examples 1 to 6 is shown below in Table 2. Table 2

The data clearly shows significantly enhanced cleaning performance from direct application cleaning of carpets according to the process of the invention (Examples 5 and 6) as compared to the comparative examples (Examples 1 to 4) . Addition of a small quantity of the polyester soil release

(1) polymer Navdeelose T into the mixture (Example 6) further enhances cleaning performance .

(l) Polyester soil release polymer ex. Navdeelase Chemicals

(2) Methoxy nonafluorobutane ex. 3M

(3) Synthetic aliphatic hydrocarbon ex. Exxon MOULD REMOVAL FROM TILES

Method

A mould spore suspension with Cladosporium cladosporioides JAP 001 was prepared according to the protocol described in British/European Standards BS EN 1275:1997 and BS:EN 1650:1998.

The mould spore suspension prepared as above was used to grow a thick and even layer of mould on pieces of unglazed,

2 porous tile cut into approximately 2.5 cm pieces. The tiles were sterilised before being treated with a melange of broth and mould spores. After incubation the mould-covered tiles were autoclaved to ensure sterility.

Pieces of mould-covered porous tile prepared as above were selected to have a similar reflectance. Prior to use, colour co-ordinates (L, a and b) of the tiles were measured using a Dr. Lange micro color reflectometer . Tiles (2.5 cm square) were cleaned by spraying with 5 ml of (i) water (ii)

(4) (4)

Shellsol T (iii) an emulsion of 1 part Shellsol T to 4 parts water. The tiles were dried overnight at 37°C and the colour co-ordinates measured again. An unused tile was also re-measured as a control. L-values and differences are tabulated below in Table 3. Results

Table 3

L-values of Tiles treated with Cladosporium cladosporioides before and after cleaning and differences

These results clearly show the superiority of the process of the invention (using the emulsion) compared with the

(₄) controls (using water alone and Shellsol T alone respectively) for removing the mould pigment from the porous tile.

(4)

Isoparaffin solvent (95% isododecane) ex Shell

Claims

1. A process of cleaning household surfaces comprising applying to the surface a temporary emulsion which is formed by the agitation of a composition comprising at least two immiscible liquids, the liquids having at least one liquid-liquid interface with an interfacial tension of at least 5 mN/m, and in which the concentration of the most polar liquid in the composition is from 10 to 90% by volume.

2. A process according to claim 1, in which the interfacial tension is at least 35 mN/m.

3. A process according to claim 1 or 2 , in which the composition comprises water and a less polar liquid selected from hydrocarbons and halogenated solvents and mixtures thereof .

4. A process according to any one of claims 1 to 3, in which the at least two immiscible liquids in the composition are density-matched.

5. A process according to any one of claims 1 to 4, in which the composition further includes a soil release polymer.

6. A process according to any one of claims 1 to 5, in which the household surface is tiled or carpeted.