WO2005059072A1

WO2005059072A1 - Fabric conditioning composition

Info

Publication number: WO2005059072A1
Application number: PCT/EP2004/012525
Authority: WO
Inventors: Laurent Soubiran
Original assignee: Unilever Plc; Unilever Nv; Hindustan Lever Limited
Priority date: 2003-12-12
Filing date: 2004-11-03
Publication date: 2005-06-30
Also published as: GB0328847D0

Abstract

A heat activated fabric conditioning composition comprises from 3 to 75 % by weight of a quaternary ammonium cationic softening material, from 5 to 70 % by weight of a nonionic surfactant and a polymeric nanoparticle comprising one or more perfume ingredients.

Description

FABRIC CONDITIONING COMPOSITION

Field of the Invention

The present invention relates to fabric conditioning compositions and preferably relates to fabric conditioning compositions comprising nanoparticles for improving perfume substantivity and/or longevity on fabrics.

Background of the Invention

Perfume deposition from conventional fabric conditioning compositions typically requires the provision of an adequate amount of the perfume ingredient in the composition to enable sufficient deposition onto fabrics without significant assistance from deposition aids. Thus, it is not unusual for only a small proportion, e.g. 30% or less, of the total perfume present in the composition to be deposited onto the fabric during the rinse stage, the remainder being undesirably lost when the rinse liquor is drained, with 80% of the deposited perfume then evaporating during the drying stage.

It is environmentally undesirable to lose such a significant proportion of the perfume both in the rinse liquor and during drying since this requires the higher levels of perfume to be present originally. Furthermore, this imposes additional unwanted expense. Perfume encapsulation has been investigated to increase perfume deposition and retention onto fabric treated with fabric conditioning products.

For instance, EP-A 0 469 228 discloses a perfume carrier and delivery system which is claimed to be suitable for use in a wash liquor and which consists of a perfume, a hydrophobic solid, a branched or linear alcohol or ester and an amphiphilic polymer derived from monomers such as ethylene oxide, acrylic acid, styrenesulphonate, acrylamide and block copolymers thereof with polyoxypropylene or polyamide.

EP-A 0 346 034 discloses a process for preparing particles of wax encapsulated actives (like perfume) for use in cleaning products by (i) dispersing actives in molten wax, (ii) emulsifying the active/wax dispersion in aqueous surfactant solution, (iii) quenching the capsules by cooling and (iv) retrieving solidified capsules.

US-A 5, 506,201 discloses a method for producing a fragrance-containing solid particle of improved substantivity for incorporation into laundry detergents which comprises of a fat component and a solid surface active agent like sorbitan ester.

It is known that waxes and fats and so the systems described above do generally not produce the desired sustained and controlled release action.

EP-A 0 617 051 discloses polymeric composition obtained by emulsion polymerisation of unsaturated monomers in the presence of a fragrance. The composition is typically used for fragrant coatings for artefacts. No details concerning the method to produce this polymer composition is disclosed.

JP-A 63/122796 discloses the use of a non fragrant latex in liquid products, such as laundry care products, comprising fragrances, to improve deposition and controlled release of fragrances on substrates. The polymer used is soft polyacrylate having low glass temperature bearing cationic or pseudo-cationic groups, and consisting essentially of polybutylacrylate .

WO 98/28396 discloses a latex having particle sizes larger than 1 to 10 microns which are produced by suspension polymerisation of vinyl monomers. A fragrance is incorporated by mixing it with the monomers prior to polymerisation or post-addition of the fragrance to the latex. The latex microparticles are surrounded by a polyhydroxy hydrocolloid layer which is claimed to enhance deposition of the perfume on substrates.

EP-A-0925776 discloses a polymer molecularly imprinted, with an organoleptic substance and prepared by solution or dispersion, polymerisation in organic media, in the presence of the imprinting substance. The polymer used binds preferentially the olfactive compounds which have been used for imprinting. Examples of selective malodour recognition are given and some of the results with laundry care products suggest a better deposition and enhanced longevity of imprinting agents. There are, however, a number of drawbacks. First, solution polymerisation is difficult to conduct at industrial scales. Second, subsequent grinding and sieving to obtain usable particles is required. Third, the use of an organic solvent is detrimental to the final loading of the polymer, due to partition of the olfactive compound between polymer and solvent.

In a conventional highly concentrated fabric conditioning composition, such as may be used on a tumble dryer sheet, a cationic fabric softening compound is typically present at a level of 40wt% or higher based on the total weight of ingredients. In such a composition, it is immediately apparent that if any anionic material were also to be present, the effectiveness of both the cationic and the anionic materials could be severely adversely affected due to a reaction/complexation of the materials with each other since a complex or the like would no longer carry the necessary charge to be able to deposit on a charged surface of the fabric being laundered. This is clearly undesirable.

Objects of the Invention

It is an object of the present invention to address one or more of the abovementioned problems and/or to provide one or more of the benefits referred to herein.

Statement of Invention

Thus, according to the present invention, there is provided a heat activated fabric conditioning composition comprising:

(a) from 3 to 75% by weight of a quaternary ammonium cationic softening material; (b) from 5 to 70% by weight of a nonionic surfactant; and

(c) a polymeric nanoparticle comprising one or more perfume ingredients.

Detailed Description of the Invention

The present invention relates to a fabric conditioning composition, more preferably a fabric softening composition, most preferably a tumble dryer cycle fabric softening composition.

In the context of the present invention, the term "comprising" denotes that the feature (s) to which it refers is/are not exhaustive and further features may be present.

Nanoparticles

The polymeric nanoparticles used in the compositions of the present invention include perfume ingredients.

The nanoparticles also bear an overall negative charge and may be referred to as anionic nanopoarticles .

Preferably the polymeric nanoparticles have a glass o temperature of greater than 50 C.

The perfume ingredients are preferably present in an amount of 5 to 50%, preferably 10 to 30% with respect to the dry polymer, and 1.4 to 14%, preferably 3.5 to 10.5% with respect to a latex dispersion of the polymer.

Furthermore, the perfume ingredients are preferably present in an amount from 3 to 30% by weight, more preferably 4 to 25% by weight, most preferably 5 to 20% by weight, e.g. 6 to 15% by weight based on the total weight of the composition.

The nanoparticles are typically obtainable by a) continuously adding a liquid monomer component and a perfume ingredient to an aqueous solution of a first initiator comprising an emulsifier and distributing the added components in the aqueous solution to obtain a reaction mixture while starting polymerisation of the monomer component in the reaction mixture at a first temperature and, while continuing the addition of the liquid monomer component and the perfume ingredient, adding a second initiator dropwise to the reaction mixture while maintaining the first temperature after terminating the addition of the liquid monomer component and the perfume ingredient increasing the temperature of the reaction mixture to a second temperature and dropwise adding a third initiator. Preferably, the addition of the monomer component and the perfume ingredient is continued during the whole step a) .

It is assumed that under these conditions the polymer particles used in the composition of the invention are imprinted by the molecules of the perfume ingredients, i.e. the polymer is formed around the individual perfume ingredients. Such polymers are also called template polymers. (Molecular) imprinting is characterised by an enhanced retention of the perfume ingredients in the particles and by a reduced diffusion of these perfume ingredients through the polymer.

The above process is also called semicontinuous batch polymerisation. The polymerisation takes place in a two phase system with homogenous distribution of the liquid monomer and the perfume composition in an aqueous solution of an emulsifier. The two phase polymerisation is either a dispersion, suspension or preferably an emulsion or mini- emulsion polymerisation. For the latter a pre-emulsion is prepared by admixing the monomer with the perfume ingredients and adding the pre-emulsion during step a) to the aqueous solution. Optionally the aqueous solution may comprise dispersed polymer seeds. Depending on the desired particle size, size distribution, fragrance release performance, etc. , the steps of the above process can be modified. The rate of the addition and the droplet size of the perfume and the monomer component and the initiator can be varied to obtain the desired particle properties. In particular, step a) can be followed by the addition of additional monomers and initiators, in order to provide an outer layer or coating of desired character on the particles. Also, the composition of the monomer and the perfume ingredients can be continuously varied in order to provide a gradient of characteristics within the particles. Such variations include: (i) variation of the temperatures, (ii) changing one or more initiators and/or initiator concentrations, (iii) changing feed rate of the monomer and perfume ingredient and (iv) changing the period of the above steps. Polymers obtained by batch radical polymerisation, where the whole monomer component and perfume ingredient is present in the reaction mixture before polymerisation starts, are less desirable for use in the compositions of the present invention.

Nanoparticles obtained by absorbing a perfume ingredient into pre-formed nanoparticles are also less desirable because they yield a less controlled release profile than those formed by the process described above.

An advantage of the polymeric nanoparticle is the extremely low amount of monomers found.

The amount of the principal monomer component is typically found in an amount of 100 ppm or less. Preferably the principal monomer component is added during the process in a significantly higher amount than the other monomer (s).

The composition of the monomer is particularly relevant to the particle performance. Monomer yielding polymers with a high glass transition temperature are particularly suitable. These encompass for example, styrene, methyl (meth) acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate and (meth) acrylic acid, acrylamide and monomers of the general formula =C (RI) -CO- (CH 2)n-X+Y-, wherein Rlis H or CH3; n is 1 or 2, X is either a trimethyl quaternary ammonium or a dimethyl sulfonium radical and Y-is a counterion. Preferred monomers are styrene, methyl (meth) acrylate and (meth) acrylic acids. It is most preferred that the principal monomer is styrene.

Cross linking monomers particularly useful for the present invention comprise divinyl benzene, trivinyl benzene, divinyl toluene, trivinyl toluene, di- and tri-acrylates like diesters - formed by (meth) acrylic acid and diols - and higher esters - formed by (meth) acrylic acid and polyols. Preferred are divinyl benzene, triethylenglycol dimethacrylate, tetraethylenglycol dimethacrylate, allylmethacrylate, diallylmaleate, triallylmaleate and 1,4- butanediol diacrylate.

The choice of emulsifier is less critical. Useful emulsifiers for emulsion and mini-emulsion polymerisation can be anionic, cationic, zwitterionic or non-ionic.

Examples of useful emulsifiers include Rewoquat®RTM50 (Ricinoylamidopropyltrimethyl-ammoniummetho sulphate, Rewoquat®CPEM (Cocopentylethoxymethyl-ammoniummetho sulphate), Ethoquat®C12 (Cocobis (2-hydroxyethyl) methylammonium chloride, Cetyltrimethylammonium bromide, Lexemul®AR (Glyceryl stearate (and) Stearamidoethyl diethylamine) , Disponil®A1080 (Mixture of ethoxylated linear fatty alcohols) , Disponal®A3065 (Mixture of ethoxylated linear fatty alcohols), Mergital®LM4L (Mixture of C12-

C13fatty alcohols ethoxylated with 4 moles of ethylene oxide Lauropal®12 (Mixture of C12-C14fatty alcohols ethoxylated with 6-15 moles of ethylene oxide, Montane®60 (Sorbitan stearate, Tween®20 (Polysorbate 20) , Tween®80 (Polysorbate 80), SDS (Sodium dodecyl sulphate, Abex®EP-227

(Aramoniumnonoxynol-77 sulphate) Lexemul®AS (Glyceryl stearate (and) Sodium lauryl sulphate) , and Dowfax®2Al (a disulphonated surfactant with tetrapropylene hydrophobe source) .

Alternatively, polymer emulsifiers can be used, either as hydrocolloid stabilising agents or as emulsifiers. Hydrocolloids of interest are poly (vinylalcohol-co- vinylacetate) copolymers, modified cellulose, polyoxyethylene and polyvinylpyrrolidone. Polymer surfactants are for example multiblock copolymers and graft copolymers containing at least one hydrophilic block and at least on hydrophobic block, like polyoxyethylene- polyoxypropylene-polyoxyethylene copolymers (ex PLURONICS) , polyether-modified dimethicones and polyether-alkyl- dimethicones (ABIL) copolymers . Cationic silicones and polymers containing polyimide moieties may be also useful.

Initiators useful for emulsion polymerisation are preferably water soluble, for instance peroxodisulphates, organic peroxides, hydroperoxides and water soluble azo-compounds. Specific examples of suitable initiators are ammonium persulphate, sodium persulphate, potassium persulphate, 1,4- diisopropylbenzene hydroperoxide, cumene hydroperoxide, 2, 2 ' -azobis (2- methylpropio-namidine) dihydrochloride and 4, 4 ' -azobis (4-cyanovaleric acid).

Particularly preferred initiators are the redox systems of ammonium- or sodium persulphates with iron (II) sulphate which allow thermic initiation at low temperatures. A typical nanoparticle for use in the compositions of the invention comprises: 67% by weight of a copolymer phase consisting e.g. of 92% by weight of styrene, 2% by weight of divinyl benzene and 6% by weight of methacrylic acid, together with about 30% by weight perfume ingredients, and 0.6 to 3% by weight of the total composition of an emulsifier as stabiliser e.g. comprising SDS, Abex®3594, Dowfax®, 2A1, Lexemul®AS and Mergital®LM4L.

The nanoparticles may be supplied or used suspended in water as latex or in solid dried form. The latex form preferably contains not more than 70% by weight of the nanoparticles.

Surprisingly it has been found that, by choosing suitable functional monomers and emulsifiers, nanoparticles bearing an opposite charge with respect to the main surfactant of the fabric conditioning composition, provide excellent controlled release properties, without affecting the stability of the end product.

Thus, anionic hard, glassy nanoparticles can impart long lasting delivery of perfume ingredients on fabrics over a long period of time and fast release of the perfume ingredients upon heating when used in a fabric conditioning composition comprising a cationic softening material.

This is particularly surprising given the traditional understanding that oppositely charged materials are incompatible in such compositions. For instance, it is a long established problem in the field of laundry that anionic carryover due the detergent used in a main wash cycle reduces the effectiveness, e.g. softening results, of a cationic softening material in the rinse cycle of a washing machine operation.

Nanoparticles that are particularly suitable for use in the compositions of the invention are produced by polymerizing a mix containing 5 to 50%, preferably 10 to 30% of perfume ingredients, 40 to 95% styrene, 0 to 10% divinyl benzene, 0 to 10% (meth) acrylic acid and 0.5 to 3% anionic emulsifier by emulsion polymerisation.

Preferably the nanoparticles with sizes in the range of several hundred nanometers can be mixed directly with the fabric conditioning composition and deposited onto the fabrics.

The surface potential of the nanoparticles is believed to control the stability of the nanoparticles in the end product. The surface potential of a colloid particle depends on a number of factors like (i) the amount of ionised chemical groups present on the surface, (ii) the nature of the emulsifier adsorbed on the particle and (iii) the amount of counterions present in the vicinity of the nanoparticle. If the partially ionizable groups consist of weak acids or weak bases, the surface potential will be also controlled by the pH of the dispersion medium. The surface potential of colloid particles is usually measured by measuring the so-called zeta-potential of the particles. A complete definition of zeta-potential can be found for example in (R.J. Hunter. "Zeta Potential in Colloid

Science", Academic Press, London, 1981). The zeta-potenial of particles in a diluted dispersion can be measured by electroosmosis and electrophoresis, whereas in concentrated dispersions, electrokinetic sonic amplitude measurements are preferred. It has been shown for optimal stability in end products containing electrically charged species, the zeta- potential should not exceed some critical values, which depend on the nature and composition of the end products.

In the fabric conditioning compositions of the present invention, it is preferred that the maximum value of the zeta-potential is -35mV or less.

The perfume which is incorporated into the nanoparticles comprises one or more perfume components in order to provide an odour desirable to consumers.

It is well known that perfume is typically provided as a mixture of components. Suitable components for use in the perfume include those described in "Perfume and Flavor Chemicals (Aroma Chemicals) by Steffen Arctander, published by the author, 1969, Montclait, N.J. (US), reprinted 1^st April 1982 Library of Congress Catalog Number 75-91398, incorporated herein.

Furthermore, it is preferred that the perfume comprises substantive perfume ingredients as described in US-A1- 2003/0050220 paragraphs 60 to 72, incorporated herein.

Additionally, perfume components as described above can be incorporated directly into the composition separately from the nanoparticles. This may be desirable where it is intended to provide fragrance release in the short

In the context of the present invention, "significant enhancement of deposition" means a measurable increase of the fragrance concentration on the substrate, "significantly improved sustained release of the perfume ingredients" means a perceivable fragrance concentration in the headspace surrounding the dry fabric after 5 days and "significantly improved fast release at higher temperature of the perfume ingredients" means an unambiguous increase of the concentration in the headspace surrounding the dry fabric during and after thermic treatment.

Cationic Fabric Softening Material

The fabric conditioning composition comprises a cationic softening material. The softening material is preferably a quaternary ammonium fabric softening material.

Particularly preferred quaternary ammonium fabric softening materials comprise two A2-28 alkyl or alkenyl groups connected to the nitrogen head group, preferably via at least one ester link. It is more preferred if the quaternary ammonium material has two ester links present.

Preferably, the average chain length of the alkyl or alkenyl group is at least C14, more preferably at least Ci_δ. Most preferably at least half of the chains have a length of Cis . It is generally preferred if the alkyl or alkenyl chains are predominantly linear, although a degree of branching, especially mid-chain branching, is within the scope of the invention.

The first group of cationic fabric softening compounds suitable for use in the invention is represented by formula (I) : [(CH₂)_n(TR)]_m

R¹-N⁺-[⁽CH₂)n⁽OH)]₃-m (D

wherein each R is independently selected from a C5-35 alkyl 1 or alkenyl group, R represents a C1-₄ alkyl, C2-₄ alkenyl or a C1-₄ hydroxyalkyl group,

0 0

T is -O-C- or -C-O-

n is 0 or a number selected from 1 to 4, m is 1, 2 or 3 and denotes the number of moieties to which it relates that pend directly from the N atom, and X is an anionic group, such as halides or alkyl sulphates, e.g. chloride, methyl sulphate or ethyl sulphate. Especially preferred materials within this group are di- alkenyl esters of triethanol ammonium methyl sulphate. Commercial examples include Tetranyl AHT-1 (di-hardened tallow ester of triethanol ammonium methyl sulphate 85% active in 15% IPA) , AT-1 (di-oleic ester of triethanol ammonium methyl sulphate 90% active) , L5/90 (palm ester of triethanol ammonium methyl sulphate 90% active) , all ex Kao, and Rewoquat WE15 (C₁₀-C₂₀ and C₁₆-C₁₈ unsaturated fatty acid reaction products with triethanolamine dimethyl sulphate quaternised 90 % active) , ex Witco Corporation.

The second group of cationic fabric softening compounds suitable for use in the invention is represented by formula (II) : TR²

(R¹^ (CH₂)_n — CH X [ID

CH₂TR²

1 wherein each R group is independently selected from C₁-₄ alkyl, hydroxyalkyl or C₂-₄ alkenyl groups; and wherein each 2 R group is independently selected from Cs-₂₈ alkyl or alkenyl groups; n is 0 or an integer from 1 to 5 and T and X are as defined above.

Preferred materials of this class such as 1,2 bis [tallowoyloxy] -3- trimethylammonium propane chloride and 1, 2-bis [oleyloxy] -3-trimethylammonium propane chloride and their method of preparation are, for example, described in US 4137180 (Lever Brothers) , the contents of which are incorporated herein.

A third group of cationic fabric softening compounds suitable for use in the invention is represented by formula (III) : R¹

(CH₂)_n — T R

1 wherein each R group is independently selected from C1-4 2 alkyl, or C2-₄ alkenyl groups; and wherein each R group is independently selected from Cs-28 alkyl or alkenyl groups; n is 0 or an integer from 1 to 5 and T and X are as defined above .

A fourth group of cationic fabric softening compounds suitable for use in the invention is represented by formula (IV) : R

R¹ - N — R X ( IV)

R²

1 wherein each R group is independently selected from C1-₄ 2 alkyl, or C₂-4 alkenyl groups; and wherein each R group is independently selected from C8-28 alkyl or alkenyl groups; and X is as defined above.

Iodine Value of the Parent Fatty Acyl group or Acid

The iodine value of the parent fatty acyl compound or acid from which the cationic softening material is formed is preferably from 0 to 140, more preferably from 0 to 100, most preferably from 0 to 60.

It is especially preferred that the iodine value of the parent compound is from 0 to 20, more preferably 0 to 9, most preferably 0 to 4, e.g. 2 or less or even 1.5 or less. Where the iodine value is 4 or less, the softening material provides excellent softening results and has improved resistance to oxidation and associated odour problems upon storage. When unsaturated hydrocarbyl chains are present, it is preferred that the cis: trans weight ratio of the material is 50:50 or more, more preferably 60:40 or more, most preferably 70:30 or more, e.g. 85:15 or more.

The iodine value of the parent fatty acid or acyl compound is measured according to the method set out in WO-Al- 01/46513.

The fabric treatment active ingredient is present in an amount from 3 to 75% by weight (active ingredient) based on the total weight of the composition, preferably 4 to 60% by weight, more preferably 5 to 50% by weight, most preferably 10 to 45% by weight.

Nonionic surfactant

The compositions further comprise a nonionic surfactant. Typically these can be included for the purpose of stabilising the compositions and, in the present invention, for providing softening benefits.

Suitable nonionic surfactants include addition products of ethylene oxide and/or propylene oxide with fatty alcohols, fatty acids and fatty amines.

Any of the alkoxylated materials of the particular type described hereinafter can be used as the nonionic surfactant. Suitable surfactants are substantially water soluble surfactants of the general formula :

R — Y — (C2H₄0) _Z — C2H₄OH

where R is selected from the group consisting of primary, secondary and branched chain alkyl and/or acyl hydrocarbyl groups; primary, secondary and branched chain alkenyl hydrocarbyl groups; and primary, secondary and branched chain alkenyl-substituted phenolic hydrocarbyl groups; the hydrocarbyl groups having a chain length of from 8 to about 25, preferably 10 to 20, e.g. 14 to 18 carbon atoms.

In the general formula for the alkoxylated nonionic surfactant, Y is typically:

--0— , —C(0)0— , —C(0)N(R) — or —C(0)N(R)R—

in which R has the meaning given above or can be hydrogen; and Z is preferably from 8 to 40, more preferably from 10 to 30, most preferably from 11 to 25, e.g. 12 to 22.

The level of alkoxylation, Z, denotes the average number of alkoxy groups per molecule.

Preferably the nonionic surfactant has an HLB of from about 7 to about 20, more preferably from 10 to 18, e.g. 12 to 16.

The nonionic surfactants are useful in the present compositions alone or in combination, and the term "nonionic surfactant" encompasses mixed nonionic surface active agents.

The nonionic surfactant is present in an amount within the range from 5 to 70% by weight based on the total weight of the composition, more preferably from 10 to 65wt%, most preferably from 20 to 55wt%, e.g. 25 to 50wt%.

The level of nonionic surfactant preferably present in the compositions on the present invention can be surprisingly high and yet will not destabilise the compositions. In typical liquid fabric softening compositions the level of nonionic surfactant is typically from 0.5 to 2.5wt%.

The use of very high levels of nonionic surfactant means that the level of cationic softening material, which is incompatible with an anionic nanoparticle, can be reduced without significantly adversely affecting the softening performance delivered.

Solvent

Optionally and advantageously, the compositions comprise a solvent for the active ingredient (s) . The solvent further optimises the viscosity and flow temperature characteristics of the composition. Additionally, the solvent may act as a humectant retarding the loss of water from the composition upon storage.

Preferably the solvent is semi-polar. Suitable solvents include any which have a flash point above the heating temperature of a tumble dryer. Ideally the solvent is also odourless.

Commercially available examples include polyols.

Particularly preferred are glycol-based solvents such as glycol ethers. The most preferred solvent is dipropylene glycol.

The solvent is preferably present at a level of from 1 to 25%, more preferably from 2 to 20%, most preferably from 3 to 10% by weight, based on the total weight of the composition.

Preferably the weight ratio of nonionic surfactant to solvent is from 1:1 to 15:1, more preferably from 3:2 to 8:1 most preferably from 2:1 to 6:1.

The combined amount of nonionic surfactant and optional solvent is preferably less than 50% by weight of the composition, more preferably less than 47%, most preferably less than 45%.

Fatty Acids

The composition preferably comprises a fatty acid.

Preferred fatty acids include hardened tallow fatty acid (available under the tradename Pristerene, ex Uniqema) . The fatty acid is preferably present at a level from 0.1 to 15% by weight based on the total weight of the composition, more preferably from 0.3 to 10%, most preferably from 0.5 to 5%, e.g. 0.7 to 4% by weight.

Fatty Alcohol - co-active softener

Optionally and advantageously, one or more un-alkoxylated fatty alcohols are present in the composition.

Preferred alcohols have a hydrocarbyl chain length of from 10 to 22 carbon atoms, more preferably 11 to 20 carbon atoms, most preferably 15 to 19 carbon atoms.

The fatty alcohol may be saturated or unsaturated, though saturated fatty alcohols are preferred as these have been found to deliver greater benefits in terms of stability, especially low temperature stability.

Suitable commercially available fatty alcohols include hardened tallow alcohol (available as Hydrenol S3, ex Sidobre Sinnova, and Laurex CS, ex Clariant) .

The fatty alcohol content in the compositions is from 0 to 10% by weight, more preferably from 0.005 to 5% by weight, most preferably from 0.01 to 3% by weight, based on the total weight of the composition.

It is particularly preferred that a fatty alcohol is present in concentrated compositions, that is in compositions with 8% or more by weight of the cationic softening agent, since unexpected desirable stability can be achieved.

Other co-active softeners

Co-active softeners may also be incorporated in an amount from 0.01 to 20% by weight, more preferably 0.05 to 10%, based on the total weight of the composition. Preferred co- active softeners include fatty esters, and fatty N-oxides.

Preferred fatty esters include fatty monoesters, such as glycerol monostearate (hereinafter referred to as "GMS"). If GMS is present, then it is preferred that the level of GMS in the composition is from 0.01 to 10% by weight, based on the total weight of the composition.

The co-active softener may also comprise an oily sugar derivative. Suitable oily sugar derivatives, their methods of manufacture and their preferred amounts are described in WO-Al-01/46361 on page 5 line 16 to page 11 line 20, the disclosure of which is incorporated herein.

Liquid Carrier

A liquid carrier is preferably employed in the instant compositions. The liquid carrier is at least partly water due to its low cost, relative availability, safety, and environmental compatibility. The liquid carrier is preferably present at a level of from 10 to 50%, more preferably from 15 to 40%, most preferably from 20 to 35% by weight based on the total weight of the composition. The level of water in the liquid carrier is more than about 50%, preferably more than about 80%, more preferably more than about 85%, by weight of the carrier.

When deposited onto fibre during the drying cycle, any water is preferably present as a continuous phase which may partially evaporate and/or remain partially associated with the active ingredient (s) .

It is believed that the nonionic surfactant and quaternary ammonium fabric softening material are solubilised into the aqueous phase at the heating temperature of the tumble dryer so that the aqueous phase acts as a carrier for depositing the quaternary ammonium fabric softening material onto fabrics. During heating, the water is then evaporated leaving the deposited fabric treatment active.

Mixtures of water and a low molecular weight, e.g. <100, organic solvent, e.g. a lower alcohol such as ethanol, propanol, isopropanol or butanol are useful as the carrier liquid. Low molecular weight alcohols including monohydric, dihydric (glycol, etc.) trihydric (glycerol, etc.), and polyhydric (polyol) alcohols are also suitable carriers for use in the compositions of the present invention.

Polymeric viscosity control agents

It is useful, though not essential, if the compositions comprise one or more polymeric viscosity control agents.

Suitable polymeric viscosity control agents include nonionic and cationic polymers, such as hydrophobically modified cellulose ethers (e.g. Natrosol Plus 330/331, ex Hercules), cationically modified starches (e.g. Softgel BDA and Softgel BD, both ex Avebe) . A particularly preferred viscosity control agent is a copolymer of methacrylate and cationic acrylamide available under the tradename Flosoft 200 (ex SNF Floerger) .

Nonionic and/or cationic polymers are preferably present in an amount of 0.001 to 5wt%, more preferably 0.002 to 4wt% by weight of active ingredient, based on the total weight of the composition.

Further Optional Ingredients

The compositions may also contain one or more optional ingredients conventionally included in fabric conditioning compositions such as fluorescers, colourants, hydrotropes, bactericides, soil-releases agents, antiredeposition agents, polyelectrolytes, enzymes, optical brightening agents, anti- shrinking agents, anti-wrinkle agents, anti-spotting agents, antioxidants, sunscreens, anti-corrosion agents, drape imparting agents, dye fixatives, sequestrants, preservatives, anti-static agents, ironing aids and dyes.

Product Form and Use

In the context of the present invention, "heat activated" means that composition is suitable for use in a domestic tumble dryer, and preferably means that the composition is substantially solid at ambient temperature, i.e. 20 C, and undergoes a transition to a substantially liquid state at the heating temperature of a domestic tumble dryer.

Since the heating temperature of a domestic tumble dryer is typically within the range from about 40 C to about 80 C, it is particularly preferred that the composition is substantially solid at temperatures below 30 C, more preferably below 32 C, most preferably below 35 C, e.g. below 37 C and is substantially liquid, or at least mobile, at temperatures above 45 C, more preferably above 40 C, most preferably above 37 C. It is desirable that the composition is fully melted at temperatures above 50 C.

According to one method of defining the temperature at which the composition flows, it is desirable that the slip point of the composi ,tion is greater than 30oC and less than 50oC, more preferably greater than 35 C and less than 47 C, most preferably greater than 37 C and less than 45 C.

The slip point of the composition is measured as defined by British Standard BS 684 section 1.3 1991 ISO 6321:1991 (UK).

The fabric treatment composition is preferably capable of remaining substantially within a dispensing device during storage and being delivered to fabrics during the heating cycle of a tumble dryer. A suitable device for use with the compositions of the invention is described in WO-A1-02/33161. Thus, it is important that the composition has viscosity characteristics which allow the transition from a storage state to a dispensing state to occur at or about the heating temperature of the heat cycle. That is, the composition should preferably be a non-flowing, high viscosity product at ambient temperatures, e.g. a solid, soft solid or gel, and should become a low viscosity product, e.g. a liquid, at the heating temperatures of the tumble dryer.

Most preferably the composition is a "gel" at ambient temperature comprising a crystalline state forming a network to give the composition a non-flowing gel or gel-like consistency. At the heating temperature of the tumble dryer, the composition is most preferably a "sol" comprising a clear or isotropic solution.

Ideally, at the heating temperature the composition is a single phase or, if multi-phasic, the dispersed phase has unit sizes smaller than a typical membrane pore size of a dispensing device. A typical membrane has a pore size in the range of 0.1 - 10 microns. For pore sizes much smaller than this dispensing becomes difficult whilst for much larger pore sizes, too much composition is released per cycle, thereby increasing the risk of staining.

Typically the composition will have a viscosity of above 375 -₁ mPa.s at a shear rate of 100s at ambient temperature, more preferably above 450 mPa.s, most preferably above 500 mPa.s, e.g. above 600 mPa.s. The viscosity of the composition at ambient temperature can be measured by first melting the composition (if necessary) , transferring it to a viscometer cup and then letting it cool to room temperature with gentle shearing.

At the heating temperature of a domestic tumble dryer, the composition will typically have a viscosity of below 350 -1 mPa.s at 100s , more preferably below 300 mPa.s, most preferably below 250 mPa.s, e.g. below 200 mPa.s.

Measurements can be made using a Haake Rotoviscometer RV20 cup and bob NV1.

Preparation

The compositions of the invention may be prepared by adding the anionic nanoparticles to an unperfumed fabric conditioning composition.

Examples

The invention will now be illustrated by the following non- limiting examples. Further modifications will be apparent to the person skilled in the art.

All values are % by weight of the active ingredient unless stated otherwise. Example 1

Firstly, a preparation of a latex containing nanoparticles is prepared as follows:

A pre-emulsion is prepared by mixing an aqueous phase, prepared by dispersing the surfactants Abex®3594 (8g) and SDS (4g) in water (lOOg), with an organic phase containing styrene (276g) , methacrylic acid (18g), divinylbenzene (6g) and Softline B53 - a perfume ex Givaudan Roure - (40g) . The aqueous and the organic phase are mixed, vortexed, homogenised (using an Ultraturrax®homogeniser) and flushed with nitrogen. A llitre reaction flask equipped with a stirrer, reflux condenser, thermometer and inlet tube for delivery from a peristaltic pump is placed in a water bath at 75 °C. During nitrogen rinsing, a first initiator (6 g Na2S208/ 30 ml water) is added dropwise into the reaction flask which contains 100 ml water, 0.3g buffer (NaHC03), 0.5g Abex®3594 and a small amount of iron (II) sulphate.

After 30 minutes the pre-emulsion and a second initiator (3g Na2S208/ 60 ml water) are separately added dropwise into the reaction flask under stirring at 420 rpm, using peristaltic pumps over a period of about 120 minutes. After terminating the addition, the reaction mixture is stirred for further 30 minutes and the bath temperature is increased up to 88 °C. Subsequently a third initiator (0.7g Na2S208/ 30 ml water) is added dropwise over a period of 30 minutes before the reaction mixture is cooled to room temperature. Finally the latex particles are filtered through a 150 micrometer sieve. Fabric conditioning compositions according to the invention are shown in table 1. They are prepared by weighing the quaternary ammonium fabric softening material, nonionic surfactant and optional solvent in a beaker and heating on a hot plate until molten (about 70 C) . The molten mixture is then added with stirring to hot water (also about 70 C) to which optional components such as a polyelectrolyte or salt had already been added. To this mixture, the perfume- containing latex nanoparticles are added and stirring is continued until a liquid is produced. The liquid is then allowed to cool.

Table 1

(1) Stepantex VL85G(85%), tallow (IV ~ 35) based TEA quaternary ammonium material with 15% DPG solvent (ex Stepan)

(2) Stepantex UL G60 80% (DPG 20%), hardened tallow (IV < 1) based TEA quaternary ammonium material with 20% DPG solvent (ex Stepan)

(3) TEA (ex Aldrich) fully quaternised with di-methyl sulphate (4) Catiofast CS (30% solution), ex BASF

(5) Genapol C200 (coco alcohol 20EO) ex Clariant

(6) Slovasol 2411, (coco alcohol 11EO) ex Sloveca

(7) dipropylene glycol (ex Dow Chemicals) . This was present in addition to any DPG present in the raw material of the quaternary ammonium material.

(8) Glycol HPHP, ex Eastham

For materials in table marked "*", the amount denotes the level of raw material including solvent.

Claims

l.A heat activated fabric conditioning composition comprising:

(c) a polymeric nanoparticle comprising one or more perfume ingredients.

2. A composition according to claim 1 wherein the polymeric nanoparticle carries an overall net negative charge .

3. A composition according to claim 1 or claim 2 wherein the polymeric nanoparticle comprises, as principal monomer, styrene.

4. A composition according to any one of the preceding claims wherein the polymeric nanoparticle comprises from 40 to 95% polystyrene.

5.^' composition according to any one of the preceding claims wherein the total amount of perfume present in the composition is in the range of from 0.01 to 10% by weight, based on the total weight of the composition.