GB2429979A

GB2429979A - Reducing leakage in encapsulated perfumes

Info

Publication number: GB2429979A
Application number: GB0518454A
Authority: GB
Inventors: Xiaoying Bian; Nigel Peter Bird; Laurent Soubiran; Jeremy Robert Westwell
Original assignee: Unilever PLC
Current assignee: Unilever PLC
Priority date: 2005-09-09
Filing date: 2005-09-09
Publication date: 2007-03-14
Also published as: GB0518454D0

Abstract

A method for reducing the leakage of perfume encapsulated in a shell comprising melamineformaldehyde in an aqueous fabric conditioning composition comprising a quaternary ammonium fabric softening agent, the method comprising adding to the composition an adjuvant selected from an alkoxylated non-ionic surfactant, an emulsified silicone and mixtures thereof such that the weight ratio of quaternary ammonium fabric softening agent to adjuvant is in the range 1 : 1 to 50 : 1, preferably 1 : 1 to 15 : 1. Also disclosed is a fabric softening composition.

Description

1 2429979 Method of Reducing Perfume Leakage from Microcapsules in Fabric

Conditioning Compositions

Technical Field

This invention relates to fabric conditioning compositions containing encapsulated perfume and are particular to the use of adjuvants to reduce the leakage of perfume from the microcapsules during storage.

Background of the invention

Fabric conditioner compositions containing encapsulated perfume for use as a rinse additive in laundry operations are known. The encapsulated perfume has the perceived advantage compared with free perfume that there is better delivery to the fabric from the rinse. Also loss during drying of the treated fabric e.g. in a tumble drier, is reduced and it will be gradually released from the fabric e.g. by rupturing the capsules during ironing and/or wear of a garment or by gradual diffusion through the capsule shell.

It is obviously not desirable that the perfume be released from the shell prematurely to the encapsulated perfume when stored under certain conditions. This is particularly the case when many capsule types, such as those having aminoplast, or cross-linked gelatin walls, are stored in aqueous compositions, particularly those containing surfactants. In these cases, although the capsule shell remains intact, the perfume may be removed from the capsule by a leaching process. The leaching mechanism may be viewed as a diffusion process with transfer occurring from the capsule core to the aqueous medium, followed by transfer to or solubilisation into the surfactant micelles or vesicles. With normal surfactant concentrations of between 1 and 30% in consumer products compared with perfume levels of 0.3 to 1% it is clear that the partitioning favours absorption by the surfactant over time.

This effect is exacerbated at elevated temperatures e.g. 30 C. Thus, the storage stability of fabric conditioning compositions containing encapsulated perfume can be problematic.

There is an ongoing need to develop techniques and formulations to improve the storage stability of fabric conditioner compositions containing encapsulated perfume.

Summary of the Invention

According to one aspect of the invention there is provided a method for reducing the leakage of perfume encapsulated in a shell comprising melamine-formaldehyde in an aqueous fabric conditioning composition comprising a quaternary ammonium fabric softening agent, the method comprising adding to the composition an adjuvant selected from an alkoxylated non- ionic surfactant, an emulsified silicone and mixtures thereof such that the weight ratio of quaternary ammonium fabric softening agent to adjuvant is in the range 1: 1 to 50: 1, preferably 1: ito 15: 1.

According to a further aspect of the invention there is provided an aqueous fabric conditioning composition comprising: (i) from 0.5 to 50, preferably I to 25, more preferably 3 to 20% by weight of a quaternary ammonium fabric softening agent, (ii) from 0.1 to 5% by weight of perfume oil, a proportion of said perfume oil being encapsulated in a shell comprising melamine- formaldehyde such that the weight ratio of free perfume oil to encapsulated perfume oil is in the range 98: 2 to 10: 90, and (iii) an adjuvant selected from an alkoxylated non-ionic surfactant, an emulsified silicone and mixtures thereof such that the weight ratio of quaternary ammonium fabric softening agent to adjuvant is in the range 1: 1 to 50: 1.

It has been found that the presence of ethoxylated non-ionic surfactant and/or emulsified silicone substantially reduces the leakage of perfume oil encapsulated in a shell comprising melamine-formaldehyde in aqueous fabric conditioner compositions containing a quaternary ammonium fabric softening agent. This effect is surprising since other compounds, such as, fatty acids and fatty alcohols appear to have little effect on leakage of perfume oil.

Quaternary Ammonium Fabric Softening Agents The fabric softening agent is a quaternary ammonium material, preferably a quaternary ammonium material containing at least one ester group. The quaternary ammonium compounds containing at least one ester group are referred to herein as esterlinked quaternary ammonium compounds.

As used herein the term ester group', when used as a group in the quaternary ammonium material, includes an ester group which is a linking group in the molecule.

It is preferred for the ester-linked quaternary ammonium compounds to contain two or more ester groups. In both monoester and the diester quaternary ammonium compounds it is preferred if the ester group(s) is a linking group between the nitrogen atom and an alkyl group. The ester group(s) is preferably attached to the nitrogen atom via another hydrocarbyl group.

Also preferred are quaternary ammonium compounds containing at least one ester group, preferably two, wherein at least one higher molecular weight group containing at least one ester group and two or three lower molecular weight groups are linked to a common nitrogen atom to produce a cation and wherein the electrically balancing anion is a halide, acetate or lower alkosulphate ion, such as chloride or methosulphate. The higher molecular weight substituent on the nitrogen is preferably a higher alkyl group, containing 12 to 28, preferably 12 to 22, e.g. 12 to 20 carbon atoms, such as coco-alkyl, tallowalkyl, hydrogenated tallowalkyl or substituted higher alkyl, and the lower molecular weight substituents are preferably lower alkyl of I to 4 carbon atoms, such as methyl or ethyl, or substituted lower alkyl e.g. hydroxy alkyl. One or more of the said lower molecular weight substituents may include an aryl moiety or may be replaced by an aryl, such as benzyl, phenyl or other Preferably the quaternary ammonium material is a compound having two C12-C22 alkyl or alkenyl groups connected to a quaternary ammonium head group via at least one ester link, preferably two ester links or a compound comprising a single long chain with an average chain length equal to or greater than C20.

More preferably, the quaternary ammonium material comprises a compound having two long chain alkyl or alkenyl chains with an average chain length equal to or greater than C14. Even more preferably each chain has an average chain length equal to or greater than C16. Most preferably at least 50% of each long chain alkyl or alkenyl group has a chain length of C18. It is preferred if the long chain alkyl or alkenyl groups are predominantly linear.

A preferred type of ester-linked quaternary ammonium material that can be used in compositions according to the invention is represented by the formula (A): 00CR2

I

(A) (R1)3N - (CH2) CH X CH200CR2 wherein each R1 group is independently selected from C1 alkyl, hydroxyalkyl or C alkenyl groups; and wherein each R2 group is independently selected from C525 alkyl or alkenyl groups; X is any suitable counter-ion, i.e. a halide, acetate or lower alkosuiphate ion, such as chloride or methosuiphate.

n is an integer from 1-5 or is 0 It is advantageous for environmental reasons if the quaternary ammonium material is biologically degradable.

Preferred materials of this class such as 1,2 bis[hardened tallowoyloxy]3- trimethylammonium propane chloride and their method of preparation are, for example, described in US-A-4 137 180. Preferab'y these materials comprise small amounts of the corresponding monoester as described in US-A-4 137 180 for example 1- hardened tallowoyloxy-2-hydroxy-3-trimethylammonium propane chloride.

Another class of preferred ester-linked quaternary ammonium materials for use in compositions according to the invention can be represented by the formula (B): R1 (B) R1 N (CH2)-T-R2 X (CH2)-T-R2 wherein R1, n, R2 and X are as defined above. 0 0 0 0

and T is -0-C- or -C-O- A preferred compound is wherein one R1 group is methyl, the other R1 group is CH2CH2OH and each n is 2. Another preferred compound is where each R1 group is methyl and n is 2.

Of the compounds of formula (B), di-(tallowyloxyethyl)-methyl hydroxyethyl methosulphate ex. Clariant and its hardened or partially hardened derivatives are most preferred. Di- (tallowyloxyethyl)-dimethyl ammonjum chloride, available from Clariant, and its hardened or partially hardened derivatives are also preferred.

Another preferred class of quaternary ammonium cationic fabric softening agent is defined by formula (C):- (C) R x where R1, R2 and X are as hereinbefore defined.

A preferred material of formula (C) is di-hardened tallow-dimethyl ammonium chloride, sold under the Trademark Arquad 2HT.

The optionally ester-linked quaternary ammonium material may contain optional additional components, as known in the art, in particular, low molecular weight solvents, for instance isopropanol and/or ethanol, and co-actives such as non-ionic softeners, for example fatty acid or sorbitan esters.

The iodine value of the softening agent is preferably from 0 to 120 more preferably from 0 to 100, and most preferably from 0 to 50. Essentially saturated material, i. e. having an iodine value of from 0 to 1, is used in especially high performing compositions. At low iodine values, the softening performance is excellent and the composition has improved resistance to oxidation and associated odour problems upon storage.

Iodine value is defined as the number of grams of iodine absorbed per bOg of test material.

NMR spectroscopy is a suitable technique for determining the iodine value of the softening agents of the present invention, using the method described in Anal. Chem., 34, 1136 (1962) by Johnson and Shoolery and in EP 593,542 (Unilever, 1993).

References to levels of cationic softening agent in this specification are to the total level of cationic softening agent, including al cationic components of a complex raw material that could enter the aqueous lamellar phase together. With a di-ester softening agent, it includes any associated mono-ester or tn-ester components that may be present.

The fabric softening agent is present in the composition preferably in a total amount of 0.5% - 50% by weight based upon the total weight of the composition, more preferably 0.5% to 35%, more preferably 1-25%, more preferably 3-25%, most preferably 3-20%.

Emulsified Silicone The emulsified silicone, is preferably, an oil-inwater emulsion. As used herein silicone is meant to include both silicone and siloxane materia's. These materials are well known in the art and include both linear and branched polymers.

The silicone preferably has a linear structure. It is preferably a nonfunctional silicone, especially one which is non-amino functional. Typical silicones are siloxanes which have the general formula RaSO(4a)/2 wherein each R is the same or different and is selected from hydrocarbon and hydroxyl groups, "a" being from 0 to 3 and in the bulk material; "a" has an average value of from 1.85-2.2.

Most preferably, the silicone is a polydi-C1alkyl (preferably a polydimethyl) siloxane end- terminated either by tn-C1.6 alkylsilyl (e.g. trimethylsilyl) or hydroxy- di- Cl.6 alkylsilyl (e.g. hydroxy-dimethylsilyl) groups, or by both.

Suitable silicone materials include aminodimethicone, polymethylalkyl siloxanes, polydimethylalkyl siloxanes, dimethicone, dimethicone copolyol, dimethiconol, disiloxane, cyclohexasiloxane, cyclomethicone, cyclopentasiloxane, phenyl dimethicone, phenyl trimethicone. These materials are commercially well known materials and are available from suppliers such as Dow Corning, Shin-Etsu, Wacker Silicones Corporation and the like. A preferred silicone is Dow Corning 245 Fluid (Dow Corning, Midland Michigan), which is described as containing greater than about 60 weight percent decamethylcyclopentasiloxane and less than or equal to about 4 weight percent dimethylcyclosiloxanes.

Amino functional silicone oils such as those described in U.S. Patents 6, 355,234 and 6, 436,383 can also be advantageously employed.

The silicone generally has a viscosity before emulsification (as measured on a Brookfield RV4 viscometer at 25 C using spindle No. 4 at 100 rpm) of from 10,000cSt to 1,000,000cSt, preferably from 30,000cSt to 750,000cSt, more preferably from 40,000cSt to 400,000cSt, most preferably 45,000cSt to 250,000cSt, eg 45,000cSt to 200,000 cSt.

Emulsification may be effected using one or more non-ionic surfactants, cationic surfactants, or mixtures thereof preferably having a non-halogen counter-ion.

The silicone material is preferably admixed to the encapsulated fragrancecontaining product after the fragrance materials are encapsulated. Optionally, the silicone material may be mixed directly with the product base either before or after the encapsulated fragrance has been added.

The emulsified silicone (as 100% active silicone) may be included in the fabric softener compositions in an amount of 0.1% to 15% by weight of the total composition (including the emulsion product containing the silicone emulsion), preferably I to 10% by weight.

Non-ionic surfactant A non-ionic surfactant may be present in order to stabilise the encapsulated perfume and perform other functions such as emulsifying any oil that may be present.

Suitable non-ionic surfactants are alkoxylated materials, particularly addition products of ethylene oxide and/or propylene oxide with fatty alcohols, fatty acids and fatty amines.

For example, a well-known class of non-ionic synthetic detergents is made available on the market under the trade name of "Pluronic". These compounds are formed by condensing ethylene oxide with an hydrophobic base formed by the condensation of propylene oxide with propylene glycol. The hydrophobic portion of the molecule which, of course, exhibits waterinsolubility has a molecular weight of from about 1500 to 1800. the addition of polyoxyethylene radicals to this hydrophobic portion tends to increase the water-solubility of the molecule as a whole and the liquid character of the products is retained up to the point where polyoxyethylene content is about 50% of the total weight of the condensation product.

Preferred materials are of the general formula: R-Y-(CH2CH2O)H wherein R is a hydrophobic moiety, typically being an alkyl or alkenyl group, said group being linear or branched, primary or secondary, and preferably having from 8 to 25, more preferably 10 to 20, and most preferably 10 to 18 carbon atoms; R may also be an aromatic group, such as a phenolic group, substituted by an alkyl or alkenyl group as described above; Y is a linking group, typically being 0, C0.O, or C0.N(R1), where R1 is H or a C1 alkyl group; and z represents the average number of ethoxylate (EO) units present, said number being 8 or more, preferably 10 or more, more preferably 10 to 30, most preferably 12 to 25, e.g. 12 to 20.

Examples of suitable non-ionic surfactants include the ethoxylates of mixed natural or synthetic alcohols in the "coco" or "tallow" chain length. Preferred materials are condensation products of coconut fatty alcohol with 15-20 moles of ethylene oxide and condensation products of tallow fatty alcohol with 10-20 moles of ethylene oxide.

The ethoxylates of secondary alcohols such as 3-hexadecanol, 2octadecanol, 4-eicosanol, and 5-eicosanol may also be used. Exemplary ethoxylated secondary alcohols have formulae C12-EO(20); C14-E0(20); C14E0(25); and C16-E0(30). Especially preferred secondary alcohols are disclosed in PCT/EP2004/003992 and include Tergitol-1 5-S-3.

Those derived from the condensation of ethylene oxide with the product resulting from the reaction of propylene oxide and ethylene diamineproducts which may be varied in composition depending upon the balance between the hydrophobic and hydrophilic elements which is desired. Examples are compounds containing from about 40% to about 80% polyoxyethylene by weight and having a molecular weight of from about 5000 to about 11,000 resulting from the reaction of ethylene oxide groups with a hydrophobic base constituted of the reaction product of ethylene diamine and excess propylene oxide, said base having a molecular weight of the order of 2500 to 3000, are satisfactory.

The condensation product of aliphatic alcohols having from 8 to 18 carbon atoms, in either straight chain or branched chain configuration, with ethylene oxide, e.g., a coconut alcohol ethylene oxide condensate having from 10 to 50 moles of ethylene oxide per mole of coconut alcohol, the coconut alcohol fraction having from 10 to 14 carbon atoms.

Useful non-ionic surfactants are disclosed in U.S. Patent 5,173,200 and include the condensation products of ethylene oxide with a hydrophobic polyoxyalkylene base formed by the condensation of propylene oxide with propylene glycol. The hydrophobic portion of these compounds has a molecular weight sufficiently high so as to render it water-insoluble. The addition of polyoxyethylene moieties to this hydrophobic portion increases the water-solubility of the molecule as a whole, and the liquid character of the product is retained up to the point where the polyoxyethylene content is about 50% of the total weight of the condensation product. Examples of compounds of this type include certain of the commercially available PluronicTM surfactants (BASF Wyandotte Corp. ), especially those in which the polyoxypropylene ether has a molecular weight of about 1500 to 3000 and the polyoxyethylene contact is about 35 to 55% of the molecule by weight i.e. Pluronic L-62.

Other useful non-ionic surfactants include the condensation products of C8-C22 alkyl alcohols with 2 to 50 moles of ethylene oxide per mole of alcohol. Examples of compounds of this type include the condensation products of C11 to C15 fatty alcohols with 3 to 50 moles of ethylene oxide per mole of alcohol which are commercially available from Shell Chemical Co., Houston, Texas, i.e. Neodol 23 to 6.5 (C12-C13 fatty alcohol condensed with about 7 moles of ethylene oxide), the PolyTergentTM SLF series from Olin Chemicals or the Tergitol SLF series from Olin Chemicals or the Tergitol series from Union Carbide i.e. Tergitol TM S-I 5, which is formed by condensing about 15 moles of ethylene oxide with a C11-C15 secondary alkanol; Tergitol N-6, which is the condensation product of about 6 moles of ethylene oxide with isolauryl alcohol (CTFA name: isolaureth-6), lncropol L-7, which is lauryl alcohol condensed with about 7 moles of ethylene oxide (Croda, Inc. ).

Other useful non-lonics include the ethylene oxide esters of alkyl mercaptans such as dodecyl mercaptan polyoxyethylene thioether, the ethylene oxide esters of fatty acids such as the lauric ester of polyethylene glycol i.e., PEG 600 monostearate (Akzo Chemie) and the lauric ester of methoxypoolyethylene glycol; the ethylene oxide ethers of fatty acid amides, the condensation products of ethylene oxide with partial fatty acid esters of sorbitol such as the lauric ester of sorbitan polyethylene glycol ether, and other similar materials, wherein the mole ratio of ethylene oxide to the acid, phenol, amide or alcohol is about 5 to 50:1.

When present, the total amount of non-ionic surfactant present is generally from 0.05 to 10%, usually 0.1 to 5%, and often 0.35 to 3.5%, based on the total weight of the composition.

The weight ratio of the quaternary ammonium fabric softening agent to the total weight of emulsified silicone and ethoxylated non-ionic surfactant is in the range 1: 1 to 50: 1, preferably 1: ito 15: 1 Encapsulated Perfume The encapsulated perfume comprises a liquid core of fragrance encapsualted within a shell which comprises melamine-formaldehyde. It is preferred that the shell comprises a single layer of polymer and is uncoated. Suitable encapsulated perfumes are known and disclosed, for example in GB 2006709, EP 1393706, EP 1407753, EP 1533364, US 4100103 US 4396670, US 4525520, US 5011634, US 5089339, US 5137646 and W002/074436.

Preferred encapsulated perfumes have a shell based on acrylamide/acrylic acid! melamine/formaldehyde.

A discussion on suitable perfumes for encapsulation will be found in EP 1533364, the disclosure of which is incorporated herein by reference. Generally the compositions comprise from 0.1 to 5% by weight of perfume and at least 2% of the perfume is encapsulated. Generally the weight ratio of free perfume to encapsulated perfume is in the range 98: 2 to 10: 90, preferably 80: 20 to 20: 80.

In addition to the fragrance materials that are to be encapsulated in the present invention, the present invention also contemplates the incorporation of solvent materials. The solvent materials are hydrophobic materials that are miscible in the fragrance materials used in the present invention. Suitable solvents are those having reasonable affinity for the fragrance chemicals and a Clog P greater than 3.3, preferably greater than 6 and most preferably greater than 10. Suitable materials include, but are not limited to triglyceride oil, mono and diglycerides, mineral oil, silicone oil, diethyl phthalate, polyalpha olefins, castor oil and isopropyl myristate. It should be noted that selecting a solvent and fragrance with high affinity for each other will result in the most pronounced improvement in stability. This specific affinity may be measured by determining the Solvent - Water partition coefficient for the fragrance material. Appropriate solvents may be selected from the following non-limiting list: Mono-, di- and tn-esters, and mixtures thereof, of fatty acids and glycerine. The fatty acid chain can range from C4-C26. Also, the fatty acid chain can have any level of unsaturation.

For instance capric/caprylic triglyceride known as Neobee M5 (Stepan Corporation). Other suitable examples are the Capmul series by Abitec Corporation. For instance, Capmul MCM.

Isopropyl mynistate Fatty acid esters of polyglycerol oligomers: R2CO[OCH2-CH(OCOR1)-CH2O-]nH, where R1 and R2 can be H or C4-C26 aliphatic chains, or mixtures thereof, and n ranges between 2 to 50, preferably 2 to 30.

Non-ionic fatty alcohol alkoxylates like the Neodol sunfactants by BASF, the Dobanol sunfactants by Shell Corporation or the BioSoft surfactants by Stepan. The alkoxy group being ethoxy, propoxy, butoxy, or mixtures thereof. In addition, these surfactants can be end-capped with methyl groups in order to increase their hydrophobicity.

Di- and tn-fatty acid chain containing non-ionic, anionic and cationic surfactants and mixtures thereof.

Fatty acid esters of polyethylene glycol, polypropylene glycol, and polybutylene glycol, or mixtures thereof.

Polyalphaolefins such as the ExxonMobil PureSym PAO line Esters such as the ExxonMobil PureSyn TM Esters Mineral oils Silicone oils such polydimethyl siloxane and polydimethyl siloxane and polydimethylcyclosiloxane Diethyl phthalate Di-isodecyl adipate The level of solvent in the core of the encapsulated fragrance material is generally greater than about 30 weight percent, preferably greater than about 50 weight percent and most preferably greater than about 70 weight percent. In addition to the solvent it is preferred that higher Clog P fragrance materials are employed. It is preferred that greater than about 60 weight percent, preferably greater than 80 and more preferably grater than about 90 weight percent of the fragrance chemicals have Clog P values of greater than about 3.3, preferably greater than about 4 and most preferably greater than about 4.5. Those with skill in the art will appreciate that many formulations can be created employing various solvents and fragrance chemicals. The use of a high level of high Clog P fragrance chemicals will likely require a lower level of hydrophobic solvent than fragrance chemicals with lower Clog P to achieve similar performance stability. As those with skill in the art will appreciate, in a preferred embodiment high Clog P fragrance chemicals and hydrophobic solvents comprise greater than about 80, preferably more than about 90 and most preferably greater than 95 weight percent of the fragrance composition. As discussed above, specific Clog P values may be measured between candidate solvents and water for the fragrance materials to be included in the core. In this way, an optimum solvent choice may be made. In fact, since most fragrances will have many ingredients, it may be preferable to measure the partitioning of a specific fragrance blend in solvent and water in order to determine the effect of any material interactions.

Fatty coactives An optional component in the compositions of the present invention is a fatty coactive. Such agents typically have a C8 to C22 hydrocarbyl chain present as part of their molecular structure. Suitable fatty coactives include C8 to C22 fatty alcohols and C8 to C22 fatty acids; of these, the C8 to C22 fatty alcohols are most preferred. A fatty coactive is particularly valuable in compositions comprising a QAC having a single C1228 group connected to the nitrogen head group, such as monoester associated with a TEA ester quat.

Preferred fatty acid coactives include hardened tallow fatty acid (available as Pristerene 4916, ex. Uniqema).

Preferred fatty alcohol coactives include C16/C18 fatty alcohols (available as Stenol and Hydrenol, ex Cognis, and Laurex CS, ex Huntsman) and behenyl alcohol, a C22 fatty alcohol, available as Lanette 22, ex Henkel.

The fatty coactives may be used at from 0.1% to 10%, particularly at from 0.2% to 5%, and especially at from 0.4 to 2% by weight, based on the total weight of the composition.

Other co-softeners may be used together with the quaternary ammonium softening agent.

When employed, they are typically present at from 0.1 to 20% and particularly at from 0.5 to 10%, based on the total weight of the composition. Preferred co-softeners include fatty esters, and fatty N-oxides.

Fatty esters that may be employed include fatty monoesters, such as glycerol monostearate, fatty sugar esters, such as those disclosed WO 01/46361 (Unilever).

Further Optional Ingredients The compositions of the invention may contain one or more other ingredients. Such ingredients include preservatives (e.g. bactericides), pH buffering agents, perfume carriers, fluorescers, colourants, hydrotropes, antifoaming agents, anti- redeposition agents, soil- release agents, polyelectrolytes, enzymes, optical brightening agents, anti-shrinking agents, anti-wrinkle agents, anti-spotting agents, anti- oxidants, sunscreens, anti-corrosion agents, drape imparting agents, anti- static agents, ironing aids and dyes.

A particularly preferred optional ingredient is an opacifier or pearlescer. Such ingredients can serve to further augment the creamy appearance of the compositions of the invention.

Suitable materials may be selected from the Aquasol OP3OX range (ex Rohm and Haas), the PuriColour White range (ex Ciba) and the LameSoft TM range (ex Cognis). Such materials are typically used at a level of from 0.01 to 1% by weight of the total composition.

Product Use The compositions of the present invention are preferably rinse conditioner compositions and may be used in the rinse cycle of a domestic laundry process.

The composition is preferably used in the rinse cycle of a home textile laundering operation, where, it may be added directly in an undiluted state to a washing machine, e.g. through a dispenser drawer or, for a toploading washing machine, directly into the drum. Alternatively, it can be diluted prior to use. The compositions may also be used in a domestic hand- washing laundry operation.

It is also possible, though less desirable, for the compositions of the present invention to be used in industrial laundry operations, e.g. as a finishing agent for softening new clothes prior to sale to consumers.

The invention will be illustrated by the following Examples in which all parts and percentages are by weight unless otherwise indicated.

Examples

Preparation of encapsulated perfume.

The methodology of EP 1407753 was adopted with the exception that the further coating of polyamine polymer was not applied.

Melamine-formaldehyde capsule slurry (made by Celessence International Ltd., West Molesey, Surrey, United Kingdom) that contains approximately28% by weight of the fragrance and 55% by weight of water was used as bare (uncharged) capsules in the following Examples. To make the melamineformaldehyde capsule slurry, a copolymer of polyacrylamide and acrylic acid was first dispersed in water together with a methylated melamineformaldehyde resin. Fragrance was then added into the solution with high speed shearing to form small droplets. Curing of the polymeric film over the fragrance droplets as capsule wall affected by increasing the solution pH to polymerise the polymers followed by heating the solution to 50 to 90 C.

Raw Materials Material Trade Name Chemical Name TEAQ Stepantex UL85 ex. Stepan 85% hardened tallow ester of tris (2-hydroxyethyl) methlyl ammonium methosuiphate) 15% Propan-2-ol Non-ionic Genapol C200 ex. Clariant Coco 20 EQ alcohol ethoxylate Silicone DC1274 ex. Dow Poly-dimethylsiloxane aqueous emulsion Tallow alcohol Stenol 16/1 8L ex. Cognis Hardened tallow alcohol (TOH) Fatty acid (FA) Pristerine 4916 ex. Uniqema Hardened tallow fatty acid Fragrance ex. International Flavours and Fragrances Fabric Conditioner Sample Preparation Fabric conditioner samples were prepared at 3.5kg scale using the following methodology.

1. Add preservative and antifoam to demineralised water and heat to 56 C 2. Pre-melt HTEAQ + any co-active (FA, TOH or non-ionic) at ca. 70 C 3. Add melt to water over 4 minutes with stirring 4. Mix for 10 minutes at 165 rpm 5. Cool with stirring to 30 C over 30 minutes 6. Add silicone with stirring, if present, at 40 C during the cooling Perfume capsules or perfume oil were post-dosed cold where present.

DSC Methodology for Determining Perfume Leakage Perfume leakage from capsules in fabric conditioner formulations was measured using differential scanning calorimetry to study the effect on the Lalpha/Lbeta phase transition temperature. This phase transition temperature is depressed in the presence of free perfume oil. Thus, the greater the leakage of perfume oil from within the capsules the larger is the depression of the phase transition temperature.

First, the effect of perfume type on depression of phase transition temperature was established using free perfume oils in a single quat type (HTEAQ). The similar perfume oils, Spring Blush, Angelique and Angelina, produced almost identical plots of depression against level of free oil. Comparing perfume oils with widely different compositions produced plots of different slope.

For the storage study, the following samples were compared over four weeks at 37 C: (i) FC base alone, i.e. no perfume (ii) FC base + 0.125% free perfume oil (iii) FC base + 0.25% free perfume oil (iv) FC base + 0.25% encapsulated perfume i.e. no free perfume oil initially In (ii), (iii) and (iv), the perfume was Spring Blush perfume ex. 1FF in every case.

The first three samples were used to establish a correlation curve from which the extent of perfume leakage could be read off for the fourth case. A separate calibration curve was set up for each storage time, in order to compensate for the effect of storage on base and/or free perfume oil.

A separate set of measurements was made for each of the following formulations: Example A 5% HTEAQ + 0.25% encapsulated perfume Example B 5% HTEAQ + 0.5% hardened tallow fatty acid + 0.25% encapsulated perfume Example C 5% HTEAQ + 0.5% hardened tallow alcohol + 0.25% encapsulated perfume Example 1 5% HTEAQ + 0.5% Coco 20E0 alcohol ethoxylate + 0.25% encapsulated perfume Example 2 5% HTEAQ + 1.67% silicone DC 1274 + 0.25% encapsulated perfume All the above figures are on a 100% basis.

Using the above approach the following results were obtained after four weeks storage at 37 C: Example % leakage after 5 % leakage after 2 % leakage after 4 days at 37 C weeks at 37 C weeks at 37 C A 20 40 55 B 38 - C 33 45 50 1 14 27 35 2 25 31 39 From the above table it can be seen that Examples I and 2 in accordance with the invention which comprise Coco 20E0 non-ionic and silicone reduced perfume leakage.

Claims

Claims 1. A method for reducing the leakage of perfume encapsulated in a

shell comprising melamine-formaldehyde in an aqueous fabric conditioning composition comprising a quaternary ammonium fabric softening agent, the method comprising adding to the composition an adjuvant selected from an alkoxylated non-ionic surfactant, an emulsified silicone and mixtures thereof such that the weight ratio of quaternary ammonium fabric softening agent to adjuvant is in the range 1: 1 to 50: 1, preferably 1: 1 to 15: 1.
2. A method as claimed in Claim I in which the quaternary ammonium softening agent comprises a compound having two alkyl or alkenyl chains with an average chain length of at least C14.
3. A method as claimed in Claim 1 in which the quaternary ammonium fabric softening agent is selected from: 00CR2 (A) (R1)3N - (CH2) CH X

I

CH200CR2 wherein each R1 group is independently selected from C alkyl, hydroxyalkyl or C2 alkenyl groups; and wherein each R2 group is independent'y selected from C828 alkyl or alkenyl groups; X is any suitable counter-ion, R1 (B) R1 N (CH2)-T-R2 X

I

(CH2)-T-R2 wherein R1, n, R2 and X are as defined above. 0 0

II II

and I is -0-C- or -C-O-; and (C) R -N----R2 x where R1, R2 and X are as hereinbefore defined.
4. A method as claimed in any preceding claim in which the quaternary ammonium fabric softening agent has an IV value of from 0 to 50.
5. A method as claimed in any preceding claim in which the quat ammonium fabric softening agent is present in an amount of from 0.5 to 50%, preferably Ito 25%, more preferably 3 to 20% by weight of the composition.
6. A method as claimed in any preceding claim in which the silicone has general formula RaSO(4ay2 wherein each R is the same or different and is selected from hydrocarbon and hydroxyl groups, "a" being from 0 to 3 and in the bulk material; preferably "a" has an average value of from 1.85-2. 2.
7. A method as claimed in Claim 6 in which the silicone is a poly di-C1C6 alkyl siloxane end-terminated by tri-C1-C6 alkylsilyl or hydroxy-diC1C6 alkyl silyl.
8. A method as claimed in Claim 7 in which the silicone is a polydimethyl siloxane.
9. A method as claimed in any preceding claim in which the non-ionic surfactant is an addition product of ethylene oxide and/or propylene oxide with a fatty alcohol, fatty amine or fatty acid.
10. A method as claimed in Claim 9 in which the non-ionic surfactant has the general formula: R-Y-(CH2CH2O)H wherein R is a hydrophobic moiety, typically being an alkyl or alkenyl group, said group being linear or branched, primary or secondary, and preferably having from 8 to 25, more preferably 10 to 20, and most preferably 10 to 18 carbon atoms; R may also be an aromatic group, such as a phenolic group, substituted by an alkyl or alkenyl group as described above; Y is a linking group, typically being 0, C0.0, or C0.N(R1), where R1 is H or a C1 alkyl group; and z represents the average number of ethoxylate (E0) units present, said number being 8 or more, preferably 10 or more, more preferably 10 to 30, most preferably 12 to 25, e.g. 12 to 20.
11. A method as claimed in Claim 10 in which the non-ionic surfactant is selected from condensation products of coconut fatty alcohol with 15-20 moles of ethylene oxide and condensation products of tallow fatty alcohol with 10-20 moles of ethylene oxide.
12. A method as claimed in any preceding claim in which the encapsulated perfume has a shell based on acrylamide/acrylic acid/melamine/formaldehyde.
13. A method as claimed in any preceding claim in which the composition comprises from 0.1 to 5% by weight of perfume and at least 2% by weight of said perfume is encapsulated.
14. A method as claimed in Claim 13 in which the weight ratio of free to encapsulated perfume is in the range 98: 2 to 10: 90, preferably 80: 20 to 20: 80.
15. A method as claimed in any preceding claim in which the composition additionally comprises a fatty complexing agent selected from fatty acids and fatty alcohols.
16. An aqueous fabric conditioning composition comprising: (i) from 0.5 to 50, preferably I to 25, more preferably 3 to 20% by weight of a quaternary ammonium fabric softening agent, (ii) from 0.1 to 5% by weight of perfume oil, a proportion of said perfume oil being encapsulated in a shell comprising melamine- formaldehyde such that the weight ratio of free perfume oil to encapsulated perfume oil is in the range 98: 2 to 10: 90, and (iii) an adjuvant selected from an alkoxylated non-ionic surfactant, an emulsified silicone and mixtures thereof such that the weight ratio of quaternary ammonium fabric softening agent to adjuvant is in the range 1: Ito 50: 1.
17. An aqueous fabric conditioning composition as claimed in Claim 16 in which the quat ammonium fabric softening composition agent is as defined in any one of Claims 2 to 5.
18. An aqueous fabric conditioning composition as claimed in Claim 16 or 17 in which the silicone is as defined in any one of C'aims 6 to 8.
19. An aqueous fabric conditioning composition as claimed in any one of Claims 16 to 18 in which the non-ionic surfactant is as defined in any one of Claims 9 to 12.
20. An aqueous fabric conditioning composition as claimed in any one of Claims 16 to 19 in which the encapsulated perfume has a shell based on acrylamide/acrylic acid/melamine/formaldehyde.
21. An aqueous fabric conditioning composition as claimed in any one of Claims 16 to 20 in which the composition additionally comprises a fatty coactive agent selected from fatty acids and fatty alcohols.