WO2005059074A1

WO2005059074A1 - Fabric conditioning composition

Info

Publication number: WO2005059074A1
Application number: PCT/EP2004/012526
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: GB0328848D0

Abstract

A solid fabric conditioning composition comprises a clay 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.

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 solid fabric conditioning composition comprising:

(a) a clay; and

(b) 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 rinse cycle or 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 0.01 to 10% by weight, more preferably 0.05 to 5% by weight, most preferably 0.5 to 4.0% 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 (Rl) -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-C_L4fatty alcohols ethoxylated with 6-15 moles of ethylene o∑cide, Montane®60 (Sorbitan stearate, Tween®20 (Polysorbate 20), Tween®80 (Polysorbate 80), SDS (Sodium dodecyl sulphate, Abex®EP-227 (Ammoniumnonoxynol-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 di ethicones 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 ef ectiveness, 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 triat 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 .

Clays

The clays that are useful components of the invented products are those which cooperate with the organic fatty softener materials to provide enhanced softening of laundry.

Such clays include the montrnoffllonite-containing clays which have swelling properties (in water) and which are of smectite structure, so that they deposit on fibrous materials, especially cotton and cotton/synthetic blends, such as cotton/polyester, to give such fibers and fabrics made from them a surface lubricity or softness. The best of the 'smectite clays for use in the present invention is bentonite and the best of the bentonites are those which have a substantial swelling capability in water, such as the sodium and potassium bentonites. Such swelling bentonites are also known as western or Wyoming bentonites, which are essentially sodium bentonite. Other bentonites, such as calcium bentonite, are normally non-swelling and usually are, in themselves, unacceptable as fabric softening agents. However, it has been found that such non-swelling bentonites exhibit even better fabric softening in combination with

PEC's than do the swelling bentonites, provided that there is present in the softening composition, a source of alkali metal or other solubilizing ion, such as sodium (which may come from sodium hydroxide, added to the composition, or from sodium salts, such as builders and fillers, which may be functional components of the composition) . Among the preferred bentonites are those of sodium and potassium, which are normally swelling, and calcium and magnesium, which are normally non- swelling. Of these it is preferred to utilize calcium (with a source of sodium being present) and sodium bentonites. The bentonites employed may be produced in the United States of America, such as Wyoming bentonite, but also may be obtained from Europe, including Italy and Spain, as calcium bentonite, which may be converted to sodium bentonite by treatment with sodium carbonate, or may be employed as calcium bentonite. Also, other montmorillonite- containing smectite clays of properties like those of the bentonites described may be substituted in whole or in part for the bentonites described herein and similar fabric softening results will be obtained.

The swellable bentonites and similarly operative clays are of ultimate particle sizes in the micron range, e.g., 0.01 to 20 microns and of actual particle sizes in the range of No's. 100 to 400 sieves, preferably 140 to 325 sieves, U.S. Sieve Series. The bentonite and other such suitable swellable clays may be agglomerated to larger particle sizes too, such as 60 to 120 sieves, but such agglomerates are not preferred unless they include the PEC('s) too (in any particulate products) .

The clays are preferably present in an amount of from 1 to 95% by weight based on the total weight of the composition, more preferably 2-90%, most preferably 10-60%. Softening Materials

A main component of the compositions is preferably an organic fatty softener.

The organic softener can be anionic or nonionic fatty chains (C10-C22 preferably C12-C18).

Anionic softeners include fatty acids soaps. Preferred organic softeners are nonionics such as fatty esters, ethoxylated fatty esters, fatty alcohols and polyols polymers. The organic softener is most preferably a higher fatty acid ester of a pentaerythritol compound, which term is used in this specification to describe higher fatty acid esters of pentaerythritol, higher fatty acid esters of pentaerythritol oligomers, higher fatty acid esters of lower alkylene -oxide derivatives of pentaerythritol and higher fatty acid esters of lower alkylene oxide derivatives of pentaerythritol oligomers. Pentaerythritol compound is often abbreviated as PEC herein, which description and abbreviation may apply to any or all of pentaerythritol, oligomers, thereof and alkoxylated derivatives thereof, as such, or more preferably and more usually, as the esters, as may be indicated by the context.

The oligomers of pentaerythritol are preferably those of two to five pentaerythritol moieties, more preferably 2 or 3, with such moieties being joined together through etheric bonds. The lower alkylene oxide derivatives thereof are preferably of ethylene oxide or pTopylene oxide monomers, dimers or polymers, which terminate in hydroxyls and are joined to the pentaerythritol or oligomer of pentaerythritol through etheric linkages. Preferably there will be one to ten alkylene oxide moieties in each such alkylene oxide chain, more preferably to 6, and there will be one to ten such groups on a PEC, depending on the oligomer. At least one of the PEC OH groups and preferably at least two, e.g., 1 or 2 to 4, are esterified by a higher fatty acid or other higher aliphatic acid, which can be of an odd number of carbon atoms .

The higher fatty acid esters of the pentaerythritol compounds are preferably partial esters. And more preferably there will be at least two free hydroxyls thereon after esterification (on the pentaerythritol, oligomer or alkoxyalkane groups) . Frequently, the number of such free hydroxyls is two or about two but sometimes it may be one, as in pentaerythritol tristearate, or as many as eight, as in pentaerythritol tetrapalmitate .

The weight ratio of clay to softening material is preferably from 1 : 2 to 100:1, more preferably from 1:1 to 50:1, most preferably from 2:1 to 20:1.

Other useful ingredients for the unit dose laundry compositions of the invention include disintegration materials to enhance the disintegration of the unit dose in the wash water. Such materials include an effervescent matrix such as citric acid combined with baking soda, or materials such as PVP polymer and cellulose. Granulating agents may be used such as polyethylene glycol; bactericides, dyes and materials to protect against colour fading, dye transfer, anti-pilling and anti-shrinkage. For purposes of enhancing the aesthetic properties of the final composition, cosmetic ingredients such as dyes, micas and waxes may be used as coating ingredients to improve the appearance and feel of the unit dose.

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.

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 o 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. The particles are then freeze dried to provide a solid.

A solid fabric conditioning composition is then prepared as follows :

Clay/Pentaerythritol ditallowate (PDT) in a 80% ratio of 83%: 17% Effervescent matrix of baking soda and citric 17% acid, Polyvinylpyrrolidone 1%, and Dye 0.03% are mixed in a Loedige-type mixer. The resulting blend is dried in an oven and the latex nanoparticles 2% are then added to the dried powder. The powder is then compacted using an alternative or rotative press mounted with appropriate dyes to provide a spherical fabric conditioning tablet weighing approximately 60g and having a diameter of from about 30 to about 35 mm.

Claims

1. A solid fabric conditioning composition comprising:

(a) a clay; and

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

2. A composition according to any one of the preceding claims wherein the polymeric nanoparticle carries an overall net negative charge.

3. A composition according to any one of the preceding claims 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. A 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.