EP1593774A2

EP1593774A2 - Ironing aid composition with nanoparticles

Info

Publication number: EP1593774A2
Application number: EP05075866A
Authority: EP
Inventors: Helen Elspeth Unilever R & D Port Sunlight Lyon; Mansur S. Unilever R & D Port Sunlight Mohammadi
Original assignee: Unilever PLC
Current assignee: Unilever PLC
Priority date: 2004-05-05
Filing date: 2005-04-14
Publication date: 2005-11-09
Also published as: GB0409963D0; EP1593774A3

Abstract

This invention relates to a perfumed ironing aid composition, which is suitable for pouring directly into the water reservoir chamber of a steam iron. It comprises hydrophobic nanoparticles, preferably fumed silica.

Description

TECHNICAL FIELD

The present invention relates to an ironing aid composition suitable for pouring directly into the water reservoir chamber of a high-throughput steam iron wherein the composition is vaporised and released through the steam vents of the iron. The invention is also directed to a method for preparing an ironing aid composition and a concentrate ironing aid composition, which, preferably after appropriate dilution provides, the ironing aid composition ready for use.

BACKGROUND OF THE INVENTION

Products that can be poured directly into the chamber of a steam iron and can effectively deliver a perfume to clothes being ironed have recently become successful in Europe. These products are water based. However, the vast majority of perfume components is essentially insoluble in water and therefore requires an additional solubiliser to provide an isotropic solution (or micro-emulsion). For example DE 296 00 628 discloses a composition with oily fragrances which are hardly soluble or not soluble at all.

The usual route to solubilise a perfume in water is to include a surfactant/emulsifier typified by anionic, cationic, amphoteric, zwitterionic or particularly nonionic surfactants, most particularly alcohol ethoxylates. Many products currently on the market use this route to solubilise a perfume and achieve some level of perfuming.

For example, GB 2 333 302 describes an ironing aid composition with a nonionic surfactant to disperse the hydrophobic fragrance.

It is known that certain products to be dosed into the chambers of a steam iron can cause problems. On the one hand it is known that modification of the surface tension of the product, as compared with water can change the flow rate of the material through the iron, or result in foaming, resulting in a less than optimal production of steam. On the other hand preservative and surfactant components can char and result in damage to the articles being ironed.

WO0210503A1 (Unilever), discloses ironing waters with soluble perfume components to avoid the undesirable effects of using surfactants in irons as the high temperatures ranging from 150-270°C encountered by the ironing water during evaporation in a domestic steam iron. Such products have become very successful in the European market under the trademark 'Vaporesse'.

Despite these advances, fragranced ironing waters cannot be used in some 'high-throughput' steam irons. If used in high throughput steam irons ironing waters eject water droplets with steam (this effect is hereafter referred to as 'carryover').

In domestic steam irons there is a reservoir to hold water which during ironing can be fed into the iron to be evaporated into steam. The steam emerges from the iron sole plate and facilitates ironing and crease removal. The rate of water delivery onto the hotplate for evaporation ranges from 5 to 20 g/minute in most steam irons. High throughput steam irons, also known as 'steam promoters', are capable of delivering a larger power/heat flux to the hot plate, and can evaporate larger volumes of water with rates higher than 35 g/minute. Philips Azur 4200 model, for example, claims water delivery rates as high as 40g/minute (continuous steam up to 40g, powerful shot of steam up to 95 g). The hot plate design in such irons enables rapid heat exchange and conversion of water into steam - this employs metallic hot plates with a hydrophilic ceramic coating which has special topological features (see F. M. White, "Heat Transfer", Addison-Wesley, Reading, USA, 1984, and US 3696861).

Using perfumed waters in steam irons in place of tap water has become popular because their fragrant 'atmosphere' transforms the chore of ironing into a more pleasant experience. However ironing waters with perfume ingredients (and particularly those with surfactant) are prone to water carry-over/leakage and are noisy. The water leakage and noise level becomes very noticeable in new steam promoters because of the larger volume of water that needs to be boiled off from the hot plate.

Conventional silicone anti-foams cannot be added to a ironing water for aesthetic and practical reasons. Clear perfume water becomes cloudy and turbid in the presence of such antifoam. Consumers dislike this. More importantly the anti-foams can burn on the hot plate and cause intense fuming and hydrophobisation of the hot plate.

BRIEF DESCRIPTION OF THE INVENTION

The present invention seeks to provide an improved ironing aid composition. We have determined that by reducing the foaming potential of ironing waters or by effective breaking of the foam film when formed this problem can be solved.
The foam breakers must be compatible with the ironing waters and inert to the irons. In particular we have discovered that hydrophobic nanoparticles act as an effective de-foamer and drastically reduces the carry-over level.

Therefore, according to one aspect of the present invention, there is provided an ironing aid composition for use in a steam iron, said composition comprising hydrophobic nanoparticles. Suitable nanoparticles have a mean size around 10-20 nm.

Preferably the nanoparticles are hydrophobic oxides, more preferably metal oxides or a silica, more preferably a fumed silica. Acrosil ™ (available in the marketplace from Degussa-Huls) is a preferred hydrophobic silica nanoparticle (17 nm in size). Other hydrophobic nanoparticles with an inorganic core, zeolites or clays, and a hydrophobic shell can also be used

Typical levels of nanoparticles are 1-100 ppm, with levels of 5-20 ppm being preferred.

Preferred nanoparticles have the capacity to adsorb perfume and so modify the expression of perfume during and after product use. They are also believed to provide lubrication and hence iron glide (ease of ironing) when delivered at sufficient levels. Additionally, as disclosed in US 2004/0067247, hydrophobic silicon containing nanoparticles bestow anti-microbial and hygiene benefits.

Without wishing to go into theory the inventors believe the problem to be caused by the foaming potential of solutions in general and perfumed waters in particular. A solution of perfume ingredients can foam on its own - even in the absence of any conventional foaming agent like surfactants which are present in some ironing waters to solubilize the perfume. We believe the nanoparticles reduce the foaming potential of a perfume solution by two routes - adsorbing the perfume from the solution and hence reducing both the dissolved concentration, x, and the surface tension gradient, dγ/dx ('Andrew's' foaming criterion) and by weakening the foam films by mechanisms well known in the anti-foam literature. Alternatively one can argue that an anti-foam or a de-foamer can achieve the same end of foam elimination by breaking the foam after it is formed.

DETAILED DESCRIPTION OF THE INVENTION

In most cases it will be preferable to have at most 2, 1, 0.5 or most preferable 0.25 wt.% of water-soluble perfume. However, some care must be taken with certain perfumes and levels may be as low as 0.08wt% or lower to ensure that all components are fully dissolved and a clear product results. A further benefit of the invention is that the hydrophobic nanoparticle will improve the expression of certain perfumes.

The composition may comprise any optional ingredients, the balance being water as described below.

Water solubility is determined by mixing the water-soluble perfume in 1 litre of demineralised water at 20 Celsius, and stirring together for 60 minutes at 300 rpm using a standard mixing blade. The resulting mixture is stored for 7 days at 20 Celsius, and after that period if the resulting mixture is in two phases, then the perfume is not water-soluble. At least 0.01 wt.% of perfume should be able to dissolve according to this test. It is preferred that at least 0.05, 0.1, 0.2, 0.25, 0.5, 1, 3 or even 5 wt.% of the perfume is able to dissolve under these conditions.

Water-soluble perfume

In one preferred embodiment the water-soluble perfumes according to the invention will comprise water-soluble solvent and perfume ingredients, and these may be the sole components of such a perfume. It is preferred that the water-soluble perfume is soluble according to the above test at least at the amount it is included in the composition, if not at a higher concentration.

With regard to the solvent in the perfume, the advantage of the presence of solvent is that it may increase the formulation space by enabling the use of more different compounds to create improved ironing aid compositions with more complex fragrances which are more consumer preferred. By using the water-soluble perfume according to the invention, less solvent may be used to stabilise the perfume ingredients in the ironing aid composition.

Therefore, according to one aspect of the invention the weight ratio of solvent to perfume ingredients in the water-soluble perfume is preferably no more than 20:1, more preferably 10:1, 6:1, 3:1 or 1:1. In some water-soluble perfumes the ratio may be as low as 1:2 or even 1:3 or 1:4.

Suitable water-soluble solvents include dipropylene glycol, propylene glycol, isopropyl alcohol (IPA), ethanol and mixtures thereof. The most preferred of these is dipropylene glycol.

Perfume ingredients (or fragrance ingredients) are well known to those skilled in the art, and are described in Perfume and Flavor Chemicals, Steffan Arctander (ISDN 75-91398). The solubility of individual perfume ingredients in water can be represented by the calculated partition coefficient (ClogP) of the ingredient between distilled water and octanol at 20 Celsius. The lower the value of ClogP, the more water soluble the ingredient. For example, raspberry ketone has a ClogP of 1.072 and is very soluble in water, whereas rose acetate has a ClogP of 4.048 and is not easily soluble in water. The ClogP values are most conveniently calculated by the "CLOGP" program, available from Daylight CIS.

The water-soluble perfumes of the present invention preferably comprise at least 5 different perfume ingredients, more preferably at least 7, and possibly 10, 12 or even 15 or more different perfume ingredients. This number of different fragrance components is usually required to provide a 'complex' fragrance suitable for use in modern laundry products.

It is therefore likely that the perfume ingredients of the water-soluble perfume used will have a range of ClogP values. A perfume with a higher proportion of components with a high ClogP value will require a higher ratio of solvent to perfume ingredients than a perfume with a lower level of ingredients with a high ClogP value. Thus, a perfume with less than 5 wt.% of perfume ingredients with a ClogP value of greater than 3 may have a ratio of solvent to perfume ingredients of 1:1 or 1:2. In contrast, a perfume where at least 20 wt.% of the perfume ingredients have ClogP values of greater than 3 may have a solvent to perfume ingredients ratio of 5:1 or 7:1.

Water

The water of the composition according to the invention should have a French Hardness of 20 or below, preferably 12 or below. Water with a French Hardness of 12 to 20 is usually termed Medium water, whilst that with a French Hardness of 5 to 12, soft water.

It is further preferred that the water of the composition has a French Hardness of less than 5 (sometimes called very soft water), and demineralised water is most preferred. 'Demineralised water' means water where a large proportion, if not substantially all, of the dissolved salts have been removed. Water where the hardness ions (Ca²⁺ and Mg²⁺) have simply been replaced by other ions (such as Na⁺) is not as preferred. The term 'Demineralised water' also includes distilled water.

It is preferred that the composition comprises at least 70 wt.%, more preferably 80, 90, 95 or 99 wt.% of water.

Preservative

The ironing aid composition of the present invention may further comprise between 0.1 ppm and 3 wt.% of a preferably water-soluble preservative.

The preservative preferably should not release or decompose to chemicals which are potentially harmful to the user at the temperatures encountered in a steam iron, i.e. preferably at 150, 200 or even 250 Celsius. A guide to safe limits of numerous chemicals is provided by Occupational Exposure Limits which are available from OHSE and are listed in EH40, available from HMSO. Many known preservatives, e.g. Bronopol ™ (Myacide), Dowicil™ 75 or 200, Germaben™ II, Germall™ I 15, Germall™ II, Glycacil™, Glydant™, Glydant™ plus, Oxaban™ A and Suttocide™ can release or breakdown to harmful or irritating chemicals (e.g. formaldehyde) at the temperatures encountered in steam irons or leave unacceptable residues in the steam irons, or have odours that mask that of the water-soluble perfumes at concentrations required to provide effective preservation against bacterial and mould growth.

If a preservative, other than those defined as preferable, is to be included in the composition, then it should not be present at an amount of greater than 0.5 wt.%, more preferably 0.1, 0.001, 0.0001 wt.%, most preferably 1 ppm.

In one embodiment of the invention, the ironing aid composition comprises at least one preservative selected from aromatic, linear or branched C1-C20 alcohols and mixtures thereof, and may be present in an amount of between 0.1 ppm and 3 wt.% or preferably 0.5 and 1 wt. %. Preferably, at least one preservative is selected from benzyl alcohol (phenoxy methanol) and phenoxy ethanol and mixtures thereof. Of these preservatives, benzyl alcohol is more preferred. If benzyl alcohol is used, preferably a high purity grade is employed, to minimise the presence of the known impurity, benzaldehyde, which is preferably essentially absent from the composition according to the invention, i.e., so low that ironing aid composition can still be safely used.

In a further embodiment of the invention, one preferred preservative comprises at least one isothiazolone-based compound, e.g., Kathon™ CG ICP II (available from Rohm and Haas), a 3:1 mixture of 5-chloro-2-methyl-3(2H)-isothiazolone and 2-methyl-3(2H)-isothiazolone with a low salt content, which may be present at an amount of between 1 and 15 ppm, more preferably 4 to 7.5 ppm.

The water solubility of the preservative can be measured as for the water soluble perfume, and according to the test defined above, at least 0.01 wt.%, more preferably 0.05, 0.1, 0.2, 0.25, 0.5, 1 or 3 wt.% of the water-soluble preservative should dissolve. In the alternative, it is preferred that the water-soluble preservative is soluble according to this test at least at the amount it is included in the composition, if not at a higher concentration.

It may not be necessary to include a preservative in the composition according to the invention, if the composition can be manufactured using good manufacturing practices and contamination of the product by bacteria and fungi is thus avoided.

Buffers

It is preferred that compositions for dosing in the water reservoir chamber of steam irons are neutral or slightly alkaline, as is most tap water. Therefore buffers may be included in the composition of the present invention in order to adjust the pH of the solution such that it is greater than or equal to 6, preferably 7 to 9 more preferably 7 to 8. Such buffers may be included in amounts of between 0.0001, preferably 0.001 to 0.1 or 1 wt. %.

Buffers which are suitable for use in the present invention should preferably be non-corrosive, low in odour and leave little deposits in the steam chamber.

Suitable buffers may include carbonate/bicarbonate, borate and phosphate salts.

Sequestrants

Compositions of the present invention may also include sequestrants and scale poisoning agents in an amount of between 0.0001, preferably 0.001 to 0.1 or 1, or even 3 wt. %, in order to prevent the deposition of limescale and other unwanted salts in the steam chamber of the iron.

Sequestrants are compounds that act to sequester (chelate) metal ions, and, for example, include phosphonic or carboxylic acid functionalities, whereas scale-poisoning agents interfere with the scale formation process. Sequestrants and scale poisoning agents which are suitable for use in the present invention should preferably be non-corrosive, low in odour and leave little deposits in the steam chamber.

Suitable sequestrants include organo diphosphonic acids, such as Dequest™ 2016 (HEDP; 1-hydroxyethylene-1,1-diphosphonic acid), organo aminophosphonates, such as Dequest™ 2047 (EDTMP), and polyaminocarboxylic acids, such as EDTA.

Scale poisoning agents include acrylic acid containing organic polymers, such as polyacrylic acid maleic anhydride copolymers (e.g. Sokolan™ CP5 from BASF and Narlex™ LD20 from National Starch), salts of polyacrylic acids, and polyacrylic acid homopolymers.

Auxiliary Solvent

Usually, the ironing aid composition according to one aspect of the invention will be prepared by mixing a water-soluble perfume with water having a French hardness of 20 or below. In most cases the water-soluble perfume will comprise water-soluble perfume ingredients and a solvent. In addition, an auxiliary solvent may be included in the invention in an amount of 0.01 to 5 or possibly 20 wt.%, more preferably 0.1 to 5 or 10 wt.%, most preferably 0.2 to 1 or 2 wt. %.

Suitable auxiliary solvents include dipropylene glycol, glycerine, propylene glycol, ethanol and isopropyl alcohol (IPA) and mixtures thereof. The most preferred of these is dipropylene glycol. We have found that dipropylene glycol may be especially useful in ironing applications as a humidifier to facilitate ironing. Therefore, another aspect of the invention provides the use of an effective amount of dipropylene glycol for an ironing aid application. The ironing aid composition comprising the effective amount of dipropylene glycol can be used either directly on laundry items before ironing or can be used via the steam chamber of a steam iron. According this aspect of the invention, the ironing aid composition comprises:

(a) an effective amount of dipropylene glycol, preferably up to and including about 25 wt.%, more preferably 15, 10, 5, or even 2 or 3 wt.%. The lower limit on the total dipropylene content may be as low as 0.001 wt.%, or may be 0.01, 0.1 or 1 wt.%;

(b) 0.001 to 5 wt. % of preferably water-soluble perfume ingredients; and

(c) water with a French Hardness of 20 or below.

The amount of ethanol and/or isopropyl alcohol (IPA) in the composition preferably does not exceed 5% by weight.

The total level of solvent in the composition, including the solvent that can be present in the water-soluble perfume, can therefore be up to and including about 25 wt.%, more preferably 15, 10, 5, or even 2 or 3 wt.%. The lower limit on the total solvent content may be as low as 0.001 wt.%, or may be 0.01, 0.1 or 1 wt.%. Since it will be obvious to the skilled person in the art that it does not matter whether the solvent is added as part of the perfume or separate from the perfume, the term water-soluble perfume is preferably to be interpreted as water-soluble perfume ingredients. Thus, preferably the ironing aid composition comprises 0.001 to 5 wt.% of water-soluble perfume ingredients and water having a French Hardness of 20 or below and a total amount of solvent of from 0.001 to 25 wt.% of the total composition. For example, for the solubility test the term water-soluble perfume preferably refers to the mixture of perfume ingredients and the total amount of solvent present in the perfume and any additional solvent.

Surfactants

Surfactants are compounds having a hydrophilic head and a hydrophobic tail which contains at least 8 carbon atoms, and can be anionic, cationic, nonionic, or amphoteric (which includes zwitterionic).

Anionic surfactants contain as their hydrophilic head a carboxylate, sulphate, sulphonate or phosphate group, whilst their hydrophobic chain contains an alkyl group of at least 8 carbon atoms, possibly in combination with an aryl group.

Cationic surfactants contain as their hydrophilic head a quaternary nitrogen group, whilst their hydrophobic chain contains one or more alkyl groups of at least 8 carbon atoms.

Nonionic surfactants are the reaction product of a hydrophobic group with a reactive hydrogen and an alkylene oxide, usually ethylene oxide. The hydrophobic group will contain at least 8 carbon atoms, and is usually a primary or secondary alcohol.

Amphoteric surfactants will either have a carboxylate, or sulphate head group, or will be an amine oxide, and will contain alkyl chains having at least 8 carbon atoms.

It is preferred that compositions of the present invention comprise less than 0.2 wt.% of these surfactants, more preferably less than 0.1, 0.05, 0.01, 0.001 wt.% and most preferably less than 1 ppm of these surfactant. It should be understood that the phrase "less than" in this case also encompasses 0 wt.% surfactant. In fact in some cases it may be preferred to have no surfactant present.

Overall composition

Compositions according to the invention may consist of a water-soluble perfume and water with a French Hardness of 20 or below, and also of any of the optional components described above.

Preferably the overall composition is storage stable at 20 °C, i.e. it does not separate into two phases on extended storage (preferably at least 1 month). It is further preferred that the overall composition is storage stable at between 5°C and 37 Celsius.

Preparation

An ironing aid composition comprising perfume can be prepared in many ways known to the person skilled in the art. However, we have now found an improved process for preparing an ironing aid composition. One advantage is that relatively high concentrations of perfume can be incorporated in the aqueous carrier with minimal bacterial contamination. An improved process for preparing an ironing aid composition comprising the step of mixing perfume with water having a French hardness of 20 or less at a temperature between 10 and 95°C, preferably 60 and 90°C, most preferably between 70 and 85°C. Preferably, the perfume is water-soluble as described above. In one preferred process the water-soluble perfume comprises water-soluble solvent and perfume ingredients, the weight ratio of water-soluble solvent to perfume ingredients being no more than 20:1. Advantageously, the nanoparticles can be admixed with the perfume components and/or the solvent prior to addition of the water. The hydrophobic particles because of their nano scale size are extremely agglomerated. We have found a preferred method based on dispersing the nanoparticles (e.g. the silica) in the neat perfume or the perfume/solvent mixture, or the solvent first, preferably with intense agitation and then disperse or dissolve this silica dispersion in the water. The resulting solutions are crystal clear and hence compatible with ironing waters.

Accordingly, a further aspect of the present invention provides a method for the preparation of an ironing water which comprises the steps of forming a pre-mix comprising:

a) hydrophobic nanoparticles, and,

b) perfume and/or a solvent

and subsequently adding the premix to water.

The mixing may be performed under low shear for relatively long periods e.g. 30 minutes at about 100 to 4000 s^-1 with for example a Sulzer static mixer (SMV type). However, it may be preferred to use higher shear rates e.g. with a Silverson dynamic mill (45/600ULS) at shear rates of 180 000 s^-1 to minimise the time needed for mixing. Most preferably is a process that combines a first step at a low shear rate of 100 to 4000 s^-1 and a second step at a high shear rate of 50 000 to 300 000 s^-1, especially in a continuous process of preparing the ironing aid composition.

Packaging

The ironing aid composition of the present invention can be packaged by any conventional means, for instance in bottles or pouches, these being made from conventional materials. It is however preferred that if the composition is packaged in a bottle, the material from which the bottle is made comprises PET (polyethylene tetraphalate). This is preferred as it prevents perfume loss from the product on storage, and is transparent. Glass is also a preferred packaging material.

It is also preferred that the bottle comprises a pour spout to aid pouring of the product from the bottle. Preferably, the pour spout comprises a through spout for the liquid composition to pass through from the bottle, an annular drip tray which surround the through spout, and a drain hole in said drip tray to allow fluid to pass into the bottle.

Concentrate

A further aspect of the present invention relates to a concentrate that when diluted with water, preferably having a French hardness of 20 or below, results in an ironing composition according to the present invention. Preferably, the dilution is such that one part of concentrate is diluted with between 0.5 to 100, more preferably, between 1 and 10, most preferably between 2 and 5 parts of water (wt/wt). The exact composition of the concentrate can be easily calculated given the desired end concentration in the ironing aid composition and the dilution factor. For example when the end concentration of perfume in the ironing aid composition has to be between 3.0 and 5.0 wt % than the dilution factor will be limited to at most 20. It will be obvious to the skilled person that when higher dilution factors are used e.g. 100, the diluted ironing aid composition will necessarily comprise lower maximal perfume levels i.e., theoretically at most 1 wt.% of perfume. In most cases in will be preferred to have perfume levels in the ironing aid composition of at most 0.5 wt.%

The concentrate could also be diluted by water having a French hardness of greater than 20 to result in a composition according to the first aspect of the invention, except containing hard water. In this aspect, the concentrate preferably contains sequestrants and/or scale-poisoning agents.

Thus, the present invention provides a concentrate ironing aid composition for use in a steam chamber of a steam iron when diluted by water comprising a water-soluble perfume, as defined above.

If water is absent from this concentrate, then the need for a preservative is reduced, or even eliminated. Therefore in one preferred embodiment of this aspect of the present invention, the concentrate contains no water or preservative. If a weaker concentrate is required, then auxiliary solvent may be required to ensure the water-soluble perfume remains solubilised in the concentrate. Auxiliary solvent may also be required if any of the additional components defined above are to be included in the concentrate.

Thus, if the amount of water in the concentrate is half that of the final product then additional solvent may be required at a level of 20 to 30 wt.%.

According to one aspect of the invention a method is provided for using a concentrate ironing aid composition comprising the step of diluting the concentrate to form an ironing aid composition comprising 0.001 to 5 wt.% water-soluble perfume and water having a French Hardness of 20 or below.

Other than in the examples, or where otherwise indicated, all numbers expressing quantities of ingredients or reaction conditions used herein are to be understood as modified in all instances by the term "about". Similarly, all percentages are weight/weight percentages of the total composition unless otherwise indicated. Where the term "comprising" is used in the specification or claims, it is not intended to exclude any terms, steps or features not specifically recited.

Examples

The invention is more fully illustrated by the following non-limiting examples showing some preferred embodiments of the invention. Ironing examples were performed with Philips Azur™ iron type

Table 1 compares the results for some known foam breakers and hydrophobic silica particles for a simple test where 3 ml of sample is boiled on a model ceramic coated aluminium disc. Note that although the other additives can be easily incorporated into an ironing water the silica had to be incorporated according to the preferred method of dispersing it in the neat perfume first.

The 'boiling score' denotes how frothing a 2 ml sample of a perfumed water becomes during boiled on a hot plate and scales between 0 to 100 - zero for demineralised water and 100 for the neat base (in this case 'Sol and Fresh' variant of 'Vaporesse'™).

The boiling characteristics of additives added to a perfumed water.
Additive (base was 'Sol and Fresh' Vaporesse ™ ex Lever Faberge)	level wt%	Boiling time/s	Boiling score
None (neat base)	0	6.41	100
1-octanol	0.001	6.57	100
Hexan-1-ol	0.001	6.72	100
2-ethyl-1-hexanol	0.001	6.77	100
Pentadecafluorooctanoic acid	0.001	5.30	100
Hydrophilic silica (ex Texassist)	0.001	4.99	95
Laponite RD Clay (ex Laponite lab.)	0.001	6.05	95
DC245 (a volatile silicone oil) (ex Dow Corning)	0.001	6.04	100
DC246 (a volatile silicone oil) (ex Dow Corning)	0.001	5.47	100
EMCA plus 70-volatile oil	0.001	6.28	100
Hydrophobic silica Acrosil R972 (Degussa-Huls)	0.001	5.02	90

Table 1 shows that the silica is more effective in reducing the foaming potential (and boiling time) of the perfumed water than the other antifoam materials. In particular, other nanoparticles which are not hydrophobic (i.e. the clay and the Zeolite) did not work.

Table 2 shows the results of noise measurements, during ironing experiments, Noise is generally reduced in the presence of silica showing that inside iron there is less foaming.

In these ironing experiments the amount of carry-over for the ironing water with perfume containing nanoparticles is reduced considerably. The carry-over was considerably less for the silica added perfumed water as assessed by measuring the surface area of the wetted patches on 3 pieces of fabric each while ironing for 5 minutes with the control and control plus 0.001% silica, see table 2.

Comparison of the amount of leakage as wet patches.
'Sol and Fresh' Vaporesse ™ ex Lever Faberge) control	control	control + 0.001 silica
Average surface area of wet atches/cm²	121	23

In table 3, the 'control' sample is 'Sol and Fresh' variant of 'Vaporesse'™ which contains 0.2%wt DPG. Further DPG is added in other experiments. 'Base' is the 'control' sample prepared without DPG.

Comparison of measured noise level while ironing with a Philips Azur iron
Ironing Time/s	Steam Boost	Demin water	Control	Control + 0.001% silica	Base + 0.001 silica + glycerol	Base + 0.001 silica (no solvent)
15		58	60	49	56	54
30		54	65	52	55	55
45		54	57	54	53	55
60	On	85	80	87	78	80
75		53	61	53	54	53
90		52	56	57	51	54
105		54	58	55	52	52
120	On	73	84	84	73	72
135		56	66	58	52	56
150		57	54	54	52	56
165		56	69	49	50	57
180	On	72	80	80	69	78
195		52	67	53	54	52
210		56	57	51	51	55
225		53	54	50	51	53
240	On	81	87	88	76	75
255		52	53	54	47	53
270		52	51	49	52	52
285		50	54	54	50	53
300	On	75	88	75	82	71

The noise level measured in dBA (dB(A) - decibels with an A-weighting for the human ear) on a hand held noise detector by placing it in front of the iron when ironing. The steam boost 'on' means that this is when the button was pressed to release a burst of steam to the cloth.

The gross negative effects of hydrophobic silica was examined by using 10 litre of a 0.001 wt% silica added perfumed water in an iron and then dismantling the iron for examination of its inner hot plate for deposits or hydrophobisation. No deposits or hydrophobic effects were found from measuring the way water droplets spread on the plate for treated and new irons. No particulate build-up effect could be seen on dark colour cloths used to examine the adverse effect of using silica nanoparticles in perfumed water.

Claims

A perfumed ironing aid composition for use in a steam iron, said composition comprising hydrophobic nanoparticles.
An ironing aid composition according to claim 1 which comprises less than 0.2 wt.%, preferably less than 0.01 wt.%, more preferably less than 0.001 wt.%, most preferably less than 1 ppm of anionic, cationic, nonionic and amphoteric surfactant.
An ironing aid composition according to either claim 1 or claim 2, wherein the water-soluble perfume comprises water-soluble solvent and perfume ingredients, the weight ratio of water-soluble solvent to perfume ingredients being no more than 20:1.
An ironing aid composition according to any one of the preceding claims, wherein the water-soluble perfume comprises at least five, preferably at least 7, more preferably at least 10 different perfume ingredients.
An ironing aid composition according to any one of the preceding claims, further comprising 0.1 ppm to 3 wt. % of a preservative.
An ironing aid composition according to claim 5, wherein the preservative is present in an amount of between 0.5 and 1 wt.%.
An ironing aid composition according to one of claims 5 and 6, wherein the preservative is selected from aromatic, linear or branched C1-C20 alcohols and mixtures thereof.
An ironing aid composition according to claim 7, wherein the preservative is selected from benzyl alcohol and phenoxy ethanol.
An ironing aid composition according to claim 7, wherein the preservative is benzyl alcohol.
An ironing aid composition according to claim 5, wherein the preservative comprises at least one isothiazolone-based compound.
An ironing aid composition according to claim 10, wherein the preservative is Kathon (RTM) CG IPC II.
An ironing aid composition according to any one of claims 10 and 11, wherein the preservative is present in an amount of between 1 and 15 ppm.
An ironing aid composition according to any one of the preceding claims, which further comprises a 0.0001 to 1 wt.% of a buffer, such that the pH of the composition is greater than or equal to 6.
An ironing aid composition according to any one of the preceding claims, which further comprises 0.0001 to 3 wt. % of sequestrants and/or scale-poisoning agents.
An ironing aid composition according to any one of the preceding claims, wherein the total amount of solvent is from 0.001 to 25 wt.%.
An ironing aid composition according to claim 15, wherein the solvent is selected from the group of dipropylene glycol, propylene glycol, isopropyl alcohol, ethanol and mixtures thereof.
An ironing aid composition according to any one of the preceding claims whereby at least 0.05 wt.% more preferably at least 0.1 wt% of said water-soluble perfume dissolves under the conditions as herein described.
An ironing aid composition according to any one of the preceding claims wherein the hydrophobic nanoparticles are silica
A method for the preparation of a perfumed ironing water which comprises the steps of forming a pre-mix comprising:

a) hydrophobic nanoparticles, and,

b) perfume and/or a solvent

and subsequently adding the premix to water.