WO2007141128A2

WO2007141128A2 - Liquid hard surface cleaning composition

Info

Publication number: WO2007141128A2
Application number: PCT/EP2007/054865
Authority: WO
Inventors: Francesca Goldoni; Sara Ferrari; Gianluca Lucchini; Paolo Mondani
Original assignee: Unilever N.V.; Unilever Plc; Hindustan Unilever Limited
Priority date: 2006-06-09
Filing date: 2007-05-21
Publication date: 2007-12-13
Also published as: ES2349265T3; UA94949C2; BRPI0712452B1; ZA200809614B; BRPI0712452A2; EP2029710B1; WO2007141128A3; EG25120A; AU2007256249B2; AU2007256249A1; BRPI0712452B8; DE602007007766D1; RU2008152067A; EP2029710A2; AR061274A1; ATE474033T1; RU2427617C2; MX2008015478A

Abstract

The present invention relates to liquid hard surface cleaning compositions and methods for cleaning hard surfaces. In particular, the invention relates to fizzing compositions. Accordingly, the present invention provides a liquid hard surface cleaning composition comprising: 0.2 - 10% by weight of an anionic surfactant, selected from C6-C9 alkyl sulphonates; 0.1 - 10% by weight of a solvent; and 0.01 - 0.3% by weight of a polymer. In this connection said hard surface cleaning compositions provide fizzing hard surface cleaning compostions.

Description

LIQUID HARD SURFACE CLEANING COMPOSITION

Field of the invention

The present invention relates to liquid hard surface cleaning compositions and methods for cleaning hard surfaces. In particular, the invention relates to fizzing compositions.

Background of the invention

Traditionally, in household cleaning the surface cleaning products have been aimed at cleaning a surface with care.

Present day consumers more and more associate various sensory cues (such as odour, colour and sound) with effective cleaning. Therefore, the presence of such cues becomes as important as effectively cleaning the hard surface. The presence of foam gives the consumer the perception that the detergent is working. An attractive colour is associated with hygiene. And a fizzing sound is perceived as active cleaning.

It is an object of the present invention to provide a fizzing hard surface cleaning composition.

We have found that a fizzing composition can be obtained by a detergent mixture with such properties that the foam formation and collapse results in a fizzing sound.

Foam is defined as a dispersion of gas in a liquid and cannot be formed from pure liquids but require a liquid plus a surface-active agent such as a surfactant. The appearance of the foam is related to the amount of air dispersed into the surfactant containing liquor. The amount and appearance of the foam the household cleaning product generates is desirably related to the expectation the consumer has from said product. It is desirable that the foam is easily formed.

Thus, it is another object that the composition can be applied by a trigger spray dispenser.

It is a further object of the invention that good cleaning results can be obtained with the composition of the invention.

Surprisingly, we have found that compositions comprising short chain surfactant, solvent and polymer, may have the fizzing properties as described above when mixed in the right concentration.

Compositions comprising similar components are disclosed in the art, but not in such concentration that the fizzing properties are obtained. For example in WO99/61569 acidic cleaning composition comprising decyl sulphate, solvent and polymer. In WO99/18182 hard surface cleaning compositions comprising lower alkyl sulphonate, polymer and solvent are disclosed, but outside the boundaries for a fizzing composition .

DE 10 2004 040 848 Al discloses toilet cleaning compositions comprising Taurin modified acrylic polymers, as well as alkyl sulphate, solvent and Xanthan gum. According to the application, said polymers leave a dirt repellent film on the surface that improves the removal of faecal dirt.

WO 96/34933 discloses glass cleaning compositions comprising linear alkyl sulphate surfactants, in particular long chain alkyl sulphate surfactants for contributing to the detergency and providing reduced filming and streaking.

Summary of the invention Accordingly, the present invention provides a liquid hard surface cleaning composition comprising:

(a) 0.2 - 10% by weight of an anionic surfactant, selected from C₆-C₉ alkyl sulphonates;

(b) 0.1 - 10% by weight of a solvent; and (c) 0.01 - 0.3% by weight of a polymer, selected from natural gums and their derivatives as well as polysaccharide thickeners and their derivatives, (d) water

The invention further provides a method for treating hard surfaces with the composition of the invention and a spray dispenser comprising the composition.

These and other aspects, features and advantages will become apparent to those of ordinary skill in the art from a reading of the following detailed description and the appended claims. For the avoidance of doubt, any feature of one aspect of the present invention may be utilised in any other aspect of the invention. It is noted that the examples given in the description below are intended to clarify the invention and are not intended to limit the invention to those examples per se. Similarly, all percentages are weight/weight percentages unless otherwise indicated. Numerical ranges expressed in the format "from x to y" are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format "from x to y", it is understood that all ranges combining the different endpoints are also contemplated. Detailed description of the invention

Without wishing to be bound to a particular theory, it is presently believed that the fizzing properties of the invention are achieved by the following foam characteristics. The composition is able to form air bubbles (foam) . The air bubbles in the foam have to be able to quickly coalesce and then also quickly collapse. The coalescing and collapsing gives a fizzing sound. To achieve this, the foam properties of the composition have to meet specific characteristics disclosed herein below.

Foam is defined as a dispersion of gas in a liquid. Stable foams can not be formed from pure liquids but require a liquid plus a surface-active agent such as a surfactant. The appearance of the foam is related to the amount of air dispersed into the surfactant containing liquor. At low amounts of gas the foam is thick and creamy while at high gas / liquor ratios the foam bubbles are separated by thin lamellae.

Maximum foam generally is obtained just below the critical micelle concentration of the surfactant system. For a high level of foam sufficient surfactant must be adsorbed at the air-water interface to provide adequate surface tension gradients, repulsion forces across foam films and sufficiently low surface tension to inhibit the effects of antifoam. Surface tension gradients are required for restoring forces opposing any external stress.

The critical micelle concentration is dependent on amongst others the molecule itself (alkyl chain length, level of branching, EO chain length, headgroup type, counter ion etc.), the ionic strength, temperature and the pH. Anionic surfactants generally have a much higher critical micelle concentration than nonionics with the same alkyl chain length.

In fizzing compositions the foam is not only easily formed but also coalesces and collapses reasonable fast, thereby giving a fizzing sound.

Short chain anionic surfactant

One component that has an effect on foam formation is surfactant. The compositions of the invention comprise a short chain anionic surfactant. This type of surfactants comprises a short alkyl chain and a charged head.

For the purpose of the invention with short chain is meant any alkyl chain from 6 to 9 carbon atoms. The charged head of the anionic surfactant is preferably sulphate or sulphonate, most preferably sulphonate.

Thus the anionic surfactant of the invention is of the general formula 1 :

R-(O)_n-SO₃ ^" M⁺ (1)

Wherein :

R is C₆-, C₇-, C₈-, Cg-alkyl or mixtures thereof, n is 0 or 1 and

M is an alkali metal ion, preferably potassium (K⁺) or sodium (Na⁺) , more preferably sodium (Na⁺) . More preferred are C₇- and C₈-alkyl surfactants according to general formula 1 above. Even more preferred are C₇- and C₈- alkyl surfactants according to general formula 1 above, wherein n=0.

The anionic surfactant is present in the composition in a concentration at or above 0.2%w/w and at or below 10%w/w. More preferably, the concentration is at or below 8%w/w, more preferable at or below 6%w/w, most preferably at or below 5%w/w. The concentration is preferably at or above 0.5%w/w, more preferably at or above l%w/w, still more preferably at or above 2%w/w, most preferably at or above 2.5%w/w.

Polymer Another component that has an influence on the foam is a thickening polymer. The polymer of the invention is a thickening polymer. The preferred types of polymer are natural gums and their derivatives as well as polysaccharide thickeners and their derivatives.

Especially preferred are natural polysaccharide gums, such as Xanthan gum, Guar gum, Locust been gum, Carrageenan Gum, etc. Xanthan gums are widely available. Examples of suitable gums are Rhodopol T (Rhodia) , Kelzan ST and Rheozan (Rhodia) , Keltrol (CP Kelco) .

Also preferred are cellulose based polysaccharide thickeners, in particular hydroxy alkyl cellulose, preferably hydroxyethyl cellulose or hydroxy propyl methyl cellulose (e.g. Natrosol HR 250 ex ISP or Mecellose ex Sunsung) . The Polymer is present in the composition in a concentration at or above 0.01%w/w and at or below 0.3%w/w. More preferably, the concentration is at or below 0.2%w/w, more preferable at or below 0.1%w/w, most preferably at or below 0.06%w/w. The concentration is preferably at or above 0.02%w/w.

The polymers of the invention are preferably stable in an acidic environment. Polymers that are instable in acidic environment are not preferred. One of the polymers that are not preferred is polyethylene glycol (PEG) .

Solvent

A third component with an effect on the foam is the solvent used in the composition.

The solvent is a water soluble solvent, wherein soluble means that the solvent is soluble in or miscible with water over the concentration range of the invention.

The solvents in the composition of the invention are preferably linear or branched lower alcohols or glycol ethers.

Preferred alcohols are methanol, ethanol and/or linear or branched propyl or butyl alcohol. The most preferred alcohol is 2-propanol.

Preferred glycol ethers are propylene glycol ethers, more preferably dipropylene glycol ethers, still more preferred are dipropylene glycol mono- and di-alkyl ethers. Most prefered is dipropylene glycol n-butyl ether (DPnB) . The solvent is present in the composition in a concentration at or above 0.1%w/w and at or below 10%w/w. More preferably, the concentration is at or below 8%w/w, more preferable at or below 6%w/w, most preferably at or below 5%w/w. The concentration is preferably at or above 0.5%w/w, more preferably at or above 1%, still more preferably at or above 2%, most preferably at or above 3%.

The compositions of the invention are aqueous and in all of the composition the mass of the composition is balanced to

100% with water. Water is not part of the solvent according to the invention.

The pH of the composition The composition of the invention is preferably acidic to neutral, pH 1 to 7, preferably pH 3 to 7.

Preferred pH adjustment compounds are organic and inorganic acids. Preferred acids are phosphoric acid, citric acid, formic acid, lactic acid, or a mix of bicarboxilic acids and sulphammic acid and mixtures thereof.

Further ingredients

The composition may further comprise common additives such as preservative, hydrotrope, buffer, salt, perfume and/or dye. Without wishing to be bound to a particular theory, it is noted that some additives have a negative influence on the fizzing of the composition.

Antifoams, in particular silicon and its emulsions have a negative effect on the fizzing effect of the formulations. The composition may also comprise a further surfactant referred to as co-surfactant. The co-surfactant, if present, is balanced in such a way that it does not affect the fizzing properties of the composition. Suitable co-surfactants are nonionics and anionics. Suitable nonionic co-surfactants are C₉-Cn alcohols with 5-10 ethylene oxide groups (e.g. Neodol 91.5, ex Shell chemicals) and Ci₂-Ci₅ alkyl polyglucosides (e.g. Glucopon 215 CS UP, ex Cognis) . Suitable anionic co- surfactants are secondary sodium Ci₄-Ci₇ alkyl sulphonates (e.g. Hostapur SAS 30, ex Clariant) . These co-surfactants are present in a concentration of less than 1.5%.

The compositions may also comprise a low amount of Ci₂-Ci₈ alkyl amine oxide or Ci₂-Ci₈ alkyl betaine. These co- surfactants are present in the composition in a concentration of less than 1.0%.

Critical micelle concentration

As mentioned above, the critical micelle concentration (CMC) is one of the important foam properties that determine the fizzing character of the composition.

The CMC can be calculated, for instance according to the methods as described in Hiemenz, P. C, and Rajogopalan, R., Principles of Colloid and Surface Chemistry, p370-375, Marcel Dekker, Inc., 1997, New York.

The CMC can also be measured by adding surfactant to an aqueous solution and measuring the conductivity against the concentration. Below, the CMC, the addition of surfactant to an aqueous solution causes an increase in the number of charge carriers and consequently, an increase in the conductivity. Above the CMC, further addition of surfactant increases the micelle concentration while the monomer concentration remains approximately constant (at the CMC level) . Since a micelle is much larger than a monomer it diffuses more slowly through solution and so is a less efficient charge carrier. A plot of conductivity against surfactant concentration is, thus expected to show a break at the CMC.

For the surfactants of the invention, the CMC is preferably above 0.05 mol/1.

It is preferred that the ratio between the molar concentration of surfactant in the mix and the CMC is below 5.0, more preferably below 2.0, most preferably below 1.5.

Foam formation and collapse

As mentioned above, the fizzing of the composition of the invention is determined by the formation of foam (bubbles) , the coalescence of the foam bubbles and the collapse of the bubbles. It is particularly preferred that the foam collapses in less than 300 seconds, more preferably within 60 seconds, still more preferably within 30 seconds, or even in less than 20 seconds.

Application

The composition is preferably applied using a trigger spray applicator. A trigger spray application enables fast and easy use for the consumer and additionally it brings a suitable amount of air into the composition, which aides in the foam formation . Accordingly, the compositions of the invention may be stored in and dispensed by any suitable means, but spray applicators are particularly preferred. Pump dispensers (whether spray or non-spray pumps) are also possible. Thus, the present invention provides a container for a liquid hard surface cleaner, the container comprising a reservoir containing the hard surface cleaning composition of the invention, and spray dispenser for dispensing the composition in the form of a spray. The spray dispenser is preferably a trigger spray but may be any mechanical means for ejecting the liquid in spray or aerosol form.

The invention further provides a method for providing a fizzing sound by applying the composition of the invention to a hard surface, by means of a spray dispenser.

Examples

The invention will now be illustrated by way of the following non-limiting examples, in which all parts and percentages are by weight unless otherwise indicated.

Example 1

In this example the effect of the chain length of the anionic surfactant on the fizzing is shown.

The cleaning properties are measured as follows: White enamel tiles (10 by 10 cm) are cleaned and dried. The tiles are covered with typical greasy soap sebum soil mainly based on ca-stearate (Nova Chimica code 26411) and artificial sebum (WFK, code 9D) using a spray applicator. The soil is prepared mixing 86g calcium stearate, 14g sebum and 666, Ig propan-2-ol , The amount of soil applied amounts to 0.04g after drying. The tiles are dried in an oven at 180⁰C for 35 minutes and left to cool down to room temperature for 2 hours.

The cleaning is carried out using a WIRA (wool industries research abrasion tester) applicator device. The tile to be cleaned is placed in the "holder" of the applicator device. A Ballerina cloth impregnated with 2Og of the composition of table 1 is fastened to the cleaning head of the applicator device, and this is rubbed across the surface of the tile using a pre-set pattern covering the whole tile for 16 full cycles for each of the compositions below.

After the WIRA applicator device has cleaned the tiles according to the method above, the tiles are rinsed under running water to remove excess cleaning product. The tiles are then left to dry at room temperature overnight.

Table 1: Compositions

The stain removal is measured by re-weighing the dried tiles and calculating the percentage soil removed as:

soil applied - soil after cleaning soil removed = 100^ soil applied The results for the soil removal are given in Table 2 below. Table 2 also shows the CMC and the calculated Molar Concentration/CMC ratio of the compositions.

Table 2 further shows the corresponding foam volume and the speed of coalescence and disappearance of the foam. The foam volume and coalescence are marked by a panel of 5 members, wherein no foam volume or coalescence is marked 0 and a high volume and coalescence is marked 10. The foam disappearance is measured in seconds needed for the foam to disappear.

Table 2: Results

It is shown that the composition with a CMC > 0.05 (composition 1, 2 and 3) have a better foam coalescence and disappearance speed than compositions 4 and 5, with a lower CMC. Thus, compositions 1, 2 and 3 give a good fizzing sound, whilst compositions 4 and 5 do not. The CMC is the calculated critical micelle concentration of the surfactant.

Example 2

In this example the effect of solvent and polymer are shown.

The cleaning methods and calculation are the same as in example 1. The compositions of Table 3 are used.

Table 3: Compositions

All of the compositions from table 3 contain the short chain surfactant of the invention. Compositions 7 and 8 contain both polymer and solvent according to the invention, whereas composition 6 does not contain polymer and composition 9 does not contain solvent.

Table 4: Results

Table 4 shows that the foam volume, coalescence and disappearance speed of the compositions according to the invention (compositions 7 and 8) is excellent and therefore result in good fizzing. The composition without solvent does not collapse adequately, whereas hardly any foam is formed in the composition without polymer, giving inadequate fizzing. All of the compositions 6-9 give adequate soil removal.

Claims

A liquid hard surface cleaning composition comprising:

(a) 0.1 - 10% by weight of an anionic surfactant, selected from C₆-C₉ alkyl sulphonates ;

(b) 0.1 - 10% by weight of a solvent; and

(c) 0.01 - 0.3% by weight of a polymer, selected from natural gums and their derivatives as well as polysaccharide thickeners and their derivatives .

(d) water

A cleaning composition according to claim 1, wherein the anionic surfactant further comprises a C₆-C₉ alkyl sulphate.

A cleaning composition according to anyone of claims 1 or 2, wherein the anionic surfactant is C₇ and/or C₈ alkyl sulphonate.

A cleaning composition according to anyone of claims 1 to 3, wherein the ratio between the molar concentration of surfactant in the composition and the CMC is below 5.0.

A cleaning composition according to anyone of claims 1 to 4, wherein the pH is 1 to 7. A method for cleaning hard surfaces comprising the step of treating the surface with a composition of any of the preceding claims.

A container for a liquid hard surface cleaning composition, the container comprising a reservoir containing the cleaning composition according to any of claims 1 to 5, and a spray dispenser for dispensing said composition in the form of a spray.

A method for providing a fizzing sound comprising the step of spraying the composition according to anyone of claim 1 to 5 from the spray dispenser according to claim 7 onto a hard surface.

Use of a composition of any of claims 1 to 4 for removing soil from hard surfaces.