WO1995027771A1

WO1995027771A1 - Fabric softening composition

Info

Publication number: WO1995027771A1
Application number: PCT/EP1995/001085
Authority: WO
Inventors: Ziya Haq; Abid Nadim Khan-Lodhi; Philip John Sams
Original assignee: Unilever Plc; Unilever N.V.
Priority date: 1994-04-07
Filing date: 1995-03-22
Publication date: 1995-10-19
Also published as: PL316652A1; CZ290296A3; RU2130522C1; CN1145091A; AU703439B2; CZ288956B6; DE69508069T2; CA2184069C; SK125696A3; HU218969B; EP0754217B1; TW340883B; MX9604035A; DE69508069D1; CN1078244C; ES2128723T3; BR9507284A; HU9602726D0; PL181174B1; CA2184069A1

Abstract

Patent application that covers the concept of solubilised rinse conditioners comprising a fabric softening compound and a zwitterionic surfactant. All product forms are covered. The invention works particularly well with HEQ.

Description

FABRIC SOFTENING COMPOSITION

Technical Field

The present invention relates to fabric softening compositions. In particular the invention relates to fabric softening compositions that have excellent stability, dispensing and dispersing properties.

Background and Prior Art

Rinse added fabric softener compositions are well known. Typically such compositions contain a water insoluble fabric softening agent dispersed in water at a level of softening agent up to 7% by weight in which case the compositions are considered dilute, or at levels from 7% to 30% in which case the compositions are considered concentrates. Fabrics can also be softened by the use of sheets coated with softening compound for use in tumble dryers. In more detail the commercially available fabric softening compounds generally form stacked lamellar structures in water which have characteristic Lβ to O phase transition temperatures.

The rinse added fabric softening compositions of the prior art soften by depositing dispersed colloidal particles of softening compound onto fabrics, whilst dryer sheets soften fabrics by direct transfer of molten softening compound, as taught by the review by R. G. Laughlin in "Surfactant Science Series 2 Volume 37 Cationic surfactants Physical Properties Pages 449 to 465. (Marcel Decker, inc, 1991)

Conventional liquid fabric softening compositions are in the form of dispersed colloidal particles of the fabric softening compound. Fabric softening compositions comprising dissolved fabric softening compound in organic solvent and powder or granular compositions have also been described.

Fabric softening compositions formed from dispersed colloidal particles have complex, unstable structures. Because of this instability there are many problems associated with conventional fabric softening compositions. The principal problems are: physically instability when stored at high and low temperatures; when frozen they are converted irreversibly to gels; it is difficult to obtain compositions that exhibit good dispersibility into the wash liquor, deposition onto the fabrics and dispensability from the washing machine dispenser drawer. Poor dispersibility results in uneven coating of fabric softener onto the laundry and in some cases spotting can occur. These problems are exacerbated in concentrated fabric softening compositions and on the addition of perfume.

Physical instability manifests itself as a thickening on storage of the composition to a level where the composition is no longer pourable, and can even lead to the irreversible formation of a gel. The formation of a gel can also occur in the dispensing drawer of a washing machine when the temperature of the drawer is increased by the influx of warm water. The thickening is very undesirable since the composition can no longer be conveniently used. Physical instability can also manifest itself as phase separation into two or more separate layers.

Concentrated products, good dispersibility and dispensability, and storage stability at low or high temperature are however desired by the consumer.

The problems associated with conventional dispersed colloidal particles are addressed by the prior art. US 4 789 491 (Chang) discloses a specific process for the formulation of aqueous dispersions of cationic softening compounds. The process is said to overcome the difficulties of product viscosity and poor dispensing and dispersing on storage.

EP 0 239 910 (Procter and Gamble) ) discloses compositions containing dispersions of either diester or monoester quaternary ammonium compounds in which the nitrogen has either two or three methyl groups, stabilized by maintaining a critical low pH.

The physical stability of rinse added fabric softener compositions has been improved by the addition of viscosity control agents or anti-gelling agents. For example in

EP 13 780 (Procter and Gamble) viscosity control agents are added to certain concentrated compositions. The agents may include C₁₀-C₁₈ fatty alcohols. More recently in EP 280 550 (Unilever) it has been proposed to improve the physical stability of dilute compositions comprising biodegradable, quaternary ammonium compounds and fatty acid by the addition of nonionic surfactants. EP 507 478 (Unilever) discloses a physically stable fabric softening composition comprising a water insoluble, biodegradable, ester-linked quaternary ammonium compounds and a nonionic stabilising agent.

Various proposals have been made to supply fabric softener in granular or powdered form. EP 111074 is typical and uses a silica to carry the softener. A disadvantage of using a carrier such as silica is that it bulks up the product and serves no function beyond making the powder compatible with other ingredients that may be contained in a washing powder. EP 569 184 (Unilever) discloses use of a granular composition to form a pre-dilute which is then added to the dispenser drawer of the washing machine.

WO 92/18593 (Procter and Gamble) discloses a granular fabric softening composition which can be added to water to form an aqueous emulsion. The composition contains a nonionic fabric softener such as a sorbitan ester and a mono-long chain alkyl cationic surfactant.

WO 93/23510 (Procter and Gamble) discloses liquid and solid fabric softeners comprising biodegradable diester quaternary ammonium fabric softening compounds and a viscosity and/or dispersibility modifier, the application also discloses specific processes for making these products. The viscosity and/or dispersibility modifier may be a single long chain, alkyl cationic or a nonionic surfactant. The solid composition^' when added to water forms an emulsion or dispersion.

Our co-pending application GB 9323268.4 discloses the use of a tegobetaine to overcome the problem of instability induced by perfume in concentrated fabric softeners.

In an attempt to overcome the problems associated with dispersed colloidal particles the prior art has turned to fabric conditioners in the form of solutions of fabric softening compounds in organic solvents. Compositions of this type are exemplified by our copending application GB 9301811.7. However on contact with water dispersed colloidal particles are still formed.

A further way of making solutions of fabric conditioners is by specific structural modifications. US 3 892 669 (Lever Brothers) discloses a clear, homogeneous, aqueous based liquid fabric softening composition and is limited to solubilised tetraalkyl quaternary ammonium salts having two short-chain alkyl groups and two long-chain alkyl groups, the longer chain groups having some methyl and ethyl branching. The solubilisers comprise of aryl sulphonates, diols, ethers, low molecular weight quaternaries, sulphobetaines, and nonionic surfactants. The specification teaches that nonionic surfactants and phosphine oxides are not suitable for use alone and only have utility as auxiliary solubilisers.

We have surprisingly found that a novel fabric softening composition can be formed without the disadvantages of the prior art. The present invention discloses fabric softening compositions having excellent softening properties yet which exhibit excellent storage stability at both high and low temperatures, good freeze thaw recovery and excellent dispensability and dispersibility when the composition is concentrated and even when the fabric softening compound is concentrated to levels greater than 30 wt%. Furthermore compositions prepared according to our invention do not suffer from loss of softening performance.

Definition of the Invention

Thus according to one aspect of the invention there is provided a fabric softening composition comprising i) a substantially water insoluble fabric softening compound comprising a compound having two C₁₂.₂₂ alkyl or alkenyl groups connected to a quaternary ammonium head group via at least one ester link or a quaternary ammonium compound comprising of a single chain with an average chain length equal to or greater than C₂₀ and; ii) a solubilising agent comprising a amphoteric surfactant and optionally a non-surfactant co-solubiliser; characterised in that when the fabric softening composition is diluted in water to a concentration of 5 wt % of (i) and (ii), at least 70 wt% of the fabric softening compound is in solution.

A further aspect of the invention provides the use of self- size-limiting molecular aggregates (as defined below) as a fabric softening composition.

Detailed Description of the Invention

Without wishing to be bound by theory it is believed that the fabric conditioner of the invention is not in conventional lamellar form, and when contacted with water may be solubilised partially in the form of self-size-limiting molecular aggregates, such as micelles or micellar solutions with solid or liquid interiors or mixtures thereof. Where the composition is in a form containing water the composition itself may be at least partially in the form of self-size- limiting molecular aggregates. It is thought that it is this new structure of the fabric softening compositions that overcomes the problems of the prior art.

Suitably the fabric softening compound and solubilising agent form a transparent mix. However, the following tests may be used to determine definitely whether or not a composition falls within the present invention.

Test I

a) The fabric softening composition is diluted with water at a concentration of 5 wt% (of the fabric softening compound and the total solubilising agent ie the nonionic surfactant and any non-surfactant cosolubiliser) . The diluate is warmed to between 60 - 80 °C then cooled to room temperature and stirred for 1 hour to ensure equilibration. A first portion of the resulting test liquor is taken and any material which is not soluble in the aqueous phase is separated by sedimentation or filtration until a clear aqueous layer is obtained. (Ultarcentrifuges or ultrafilters can be used for this task. ) The filtration may be performed by passing through successive membrane filters of 1 μm,

0.45 μm and 0.2 μm.

b) The concentration of the fabric softening compound in the clear layer is measured by titrating with standard anionic surfactant (sodium dodecyl sulphate) using dimidiumsulphide disulphine blue indicator in a two- phase titration with chloroform as extracting solvent.

c) The titration with anionic surfactant is repeated with a second portion of fabric softening composition which has been diluted but not separated.

d) Comparison of b) with c) should show that the concentration of fabric softening compound in b) is at least 70 wt% (preferably 80 wt%) of the concentration of fabric softening compound in c) . This demonstrates that the fabric softening compound was in solution.

Test II

a) The fabric softening composition is diluted as for Test I. b) The viscosity of the diluate at a shear rate of llOs-1 is measured. c) The diluate is warmed to 60°C and held at this temperature for 1 -day. d) The diluate is cooled to 20°C and the viscosity is once again measured at a shear rate of llOs-1. e) Comparison between the viscosities of b) and c) should show that they differ by less 5 mPas.

It is preferable if the fabric softening compositions of the invention conforms to the following test:

Test III

a) The fabric softening composition is diluted as for Test I. b) The viscosity of the diluate at a shear rate of llOs-1 is measured. c) The diluate is frozen and thawed. d) The viscosity is once again measured at a shear rate of llOs-1. e) Comparison between the viscosities of b) and c) should show that they differ by less than 10 mPaS.

The fabric softening compositions according to the invention may be translucent. Translucent in the context of this invention means that when a cell 1cm in depth is filled with the fabric softening composition, "Courier 12 point" typeface can be read through the cell.

A further advantage of the present invention is that the softening of the composition is enhanced over compositions of the prior art comprising similar levels of fabric softening compound. 95/27771

- 9 -

The present invention has the advantage that high levels of perfume can be tolerated without adversely effecting the stability of the product.

The Fabric Softening Compound

The fabric softening compound is suitably a water insoluble quaternary ammonium material comprising a single alkyl or alkenyl chain length equal to or greater than C₂₀ or, more preferably, the softening compound comprising a polar head group and two alkyl or alkenyl chains each having an average chain length equal to or greater than C₁₂ such as a quaternary ammonium material having two C₁₂.₂₂ alkyl or alkenyl groups connected to the quaternary ammonium head group via at least one ester link.

Preferably the fabric softening compound of the invention has two long chain alkyl or alkenyl chains with an average chain length equal to or greater than C₁₄. More preferably each chain has an average chain length equal 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 of the fabric softening compound are predominantly linear.

The fabric softening compounds used in the compositions of the invention are molecules which provide excellent softening, characterised by chain melting -Lβ to LOC - transition temperature greater than 25°C, preferably greater than 35°C, most preferably greater than 45°C. This Lβ to LO transition can be measured by DSC as defined in "Handbook of Lipid Bilayers, D Marsh, CRC Press, Boca Raton Florida, 1990 (Pages 137 and 337) . Substantially insoluble fabric softening compounds in the .context of this invention are defined as fabric softening compounds having a solubility less than 1 x 10^"3 wt% in demineralised water at 20°C. Preferably the fabric softening compounds have a solubility less than 1 x 10^"4 Most preferably the fabric softening compounds have a solubility at 20°C in demineralised water from 1 x 10^"8 to 1 x 10^"6-

Preferred fabric softening compounds are quaternary ammonium compounds.

It is especially preferred if the fabric softening compound is a water insoluble quaternary ammonium material which comprises a compound having two C₁₂.₁₈ alkyl or alkenyl groups connected to the molecule via at least one an ester link. It is more preferred if the quaternary ammonium material has two ester links present. The especially preferred ester-linked quaternary ammonium material for use in the invention can be represented by the formula:

R¹

R N⁺ (CH, .,-T-R

(CH₂)_n-T-R²

wherein each R¹ group is independently selected from C___t alkyl, hydroxyalkyl or C_2-4 alkenyl groups; and wherein each R² group is independently selected from C₈_₂₈ alkyl or alkenyl groups;

O O

T is -O-C- or -C-0-; and n is an integer from 0-5. Di (tallowyloxyethyl)dimethyl ammonium chloride, available from Hoechst, is especially preferred.

A second preferred type of quaternary ammonium material can be represented by the formula:

OOCR²

(R¹)₃N⁺- (CH₂)_n CH

I CH₂OOCR²

wherein R¹, n and R² are as defined above.

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 4 137 180 (Lever Brothers) . Preferably these materials comprise small amounts of the corresponding monoester as described in US 4 137 180 for example 1-hardened tallowoyloxy -2-hydroxy -3-trimethylammonium propane chloride.

The AmphPter c Solufriliser

The solubilising agent is an amphoteric surfactant, and is characterised in terms of its phase behaviour. Suitable solubilising agents are amphoteric surfactants for which, when contacted within water, the first lyotropic liquid crystalline phase formed is normal cubic (II) or normal cubic-bicontinuous (VI) or hexagonal (HI) or nematic (Nel) , or intermediate (Intl) phase as defined in the article by G J T Tiddy et al, J Chem Soc. Faraday Trans. 1., 79, 975, 1983 and G J T Tiddy , "Modern Trends of Colloid Science in Chemistry and Biology", Ed. H-F Eicke, 1985 Birkhauser Verlag Basel] . Surfactants forming LO phases at concentrations of less than 20 wt% are not suitable.

In the context of this invention amphoteric surfactants are defined as substances with molecular structures consisting of a hydrophilic and hydrophobic part . The hydrophobic part consists of a hydrocarbon and the hydrophilic part consists of both a positive and a negative group. Preferred amphoteric surfactants include amine oxides, betaines including sulphobetaines and tegobetaines, phosphine oxides and sulphoxides.

Mixtures of solubilising agents may be used.

For compositions in solid form, especially powder, the solubilising is desirably solid at room temperature as this provides crisp composition particles.

It is particularly advantageous if the solubilising agent further comprises a non-surfactant co-solubiliser. Preferred co-solubilisers include propylene glycol, urea , acid amides up to and including chain lengths of C_6/ citric acid and other poly carboxylic acids as disclosed in EP 0 404 471 (Unilever), glycerol, sorbitol and sucrose. Particularly preferred are polyethylene glycols (PEG) having a molecular weight ranging from 200 - 6000, most preferably from 1000 to 2000.

It is preferred if the ratio of co-solubiliser to amphoteric surfactant is from to 2:1 to 1:40. Preferably the ratio of co-solubiliser to nonionic surfactant is less than 1:1, more preferably 1:5. It is advantageous if the weight ratio of solubilising agent (where relevant this would also include the co-solvent) to fabric softening compound is greater than 1:6, preferably greater than 1:4, more preferably equal to or greater than 2:3. It is advantageous if the ratio of solubilising agent to fabric softening compound is equal to or below 4:1, more preferably below 3:2.

It is beneficial if the solubilising agent/ co-solubiliser is present at a level greater than 5 wt% of the total composition, preferably at a level greater than 10 wt%.

The solubilising agent/ co-solubiliser may be present at a level greater than 20 wt% of the total composition, or even at a level greater than 30 wt%. Such higher levels are especially preferred where the fabric softening composition is a solid.

Composition PH

The compositions of the invention preferably have a pH of more than 1.5, more preferably less than 5.

Other Ingredients

The composition can also contain fatty acids, for example C₈ - C₂₄ alkyl or alkenyl monocarboxylic acids, or polymeric carboxylic acids. Preferably saturated fatty acids are used, in particular, hardened tallow C₁₆-C₁₈ fatty acids.

The level of fatty acid material is preferably more than 0.1% by weight, more preferably more than 0.2% by weight. Especially preferred are concentrates comprising from 0.5 to 20% by weight of fatty acid, more preferably 1% to 10% by weight. The weight ratio of fabric softening compound to fatty acid material is preferably from 10:1 to 1:10.

Compositions according to the present invention may contain detergency builders and/or anionic surfactants as desired. However it is especially preferred that the composition is substantially free of builders. It is also preferred that the composition be substantially free of anionic surfactant.

Suitably the composition is substantially free of nonionic hydrophobic organic materials such as hydrocarbons and hydrocarbyl esters of fatty acids.

The composition can also contain one or more optional ingredients, selected from non-aqueous solvents, pH buffering agents, perftomes, perfume carriers, fluorescers, colorants, hydrotropes, antifoaming agents, antiredeposition agents, polymeric or other thickeners, enzymes, optical brightening agents, opacifiers, anti-shrinking agents, anti-wrinkle agents, anti-spotting agents, germicides, fungicides, anti- oxidants, anti-corrosion agents, drape imparting agents, antistatic agents and ironing aids.

Product Form

The product may be in any product form. Particularly preferred forms are liquid and solid compositions and compositions suitable for coating onto a dryer sheet. Solid composition in this context includes compositions in the form of a tablet, a gel, a paste and preferably granules or a powder.

The composition may be used in a turnble drier but is preferred for use in a washing machine for example by dispensing the composition via a drawer of a washing machine optionally with dilution prior to dosing into the dispensing .drawer.

Preparation of the Composition

The invention further provides a process for preparing a rinse conditioner, as described above, which comprises the steps of:

i) mixing the substantially water insoluble fabric softening compound and the solubilising agent, preferably by co-melting;

ii) adding the resulting mixture to conventional ingredients for example, water.

Alternatively the composition may be prepared by the independent addition of the water insoluble fabric softening compound and the solubilising agent to conventional ingredients.

Compositions in solid form may be prepared by spray drying, freeze drying, milling, extraction, cryogenic grinding or any other suitable means.

The invention will now be illustrated by the following non- limiting examples. In the examples all percentages are expressed by weight.

Comparative Examples are designated by letters, while Examples of the invention are designated by numbers.

Preparation of Examples The following examples were prepared by one of the following methods:

1) co-melting the fabric softening compound in the solubilising agent and adding the resulting dispersion in the required amount of hot water.

2) Sequentially adding the fabric softening compound and the solubilising agent to hot water.

In the comparative cases where there is no solubilising agent present the cationic is dispersed in hot water (liquid compositions) .

In the Examples:

HT TMAPC = 1,2 bis [hardened tallowoyloxy] -3- trimethylammonium propane chloride

DEQA = di (tallowyloxyethyl)dimethyl ammonium chloride

Softness Evaluation

Softening performance was evaluated by adding 0. lg of fabric softening compound (2ml of a 5% a.d. dispersion) for liquids to 1 litre of tap water, 10°FH, at ambient temperature containing 0.001% (w/w) sodium alkyl benzene sulphonate (ABS) in a tergotometer. The ABS was added to simulate carryover of anionic detergent from the main wash. Three pieces of terry towelling (8cm x 8cm, 40g total weight) were added to the tergotometer pot. The cloths were treated for 5 minutes at 65 rpm, spin dried to remove excess liquor and line dried overnight .

Softening of the fabrics was assessed by an expert panel of 4 people using a round robin paired comparison test protocol. Each panel member assessed four sets of test cloths. Each set of test cloths contained one cloth of each test system under a evaluation. Panel members were asked to assess softness on a 8 point scale. Softness scores were calculated using an "Analysis of Variance" technique. Lower values are indicative of better softening.

Examples 1 to 3

The following examples were made according to either of the standard methods.

Example wt (g)

Ingredient 1 2 3

HT TMAPC 1.2 1.2 0.9

CIO Sulphobetaine 0.3 - -

C14 Sulphobetaine - 0.3 0.6

Water 8.5 8.5 8.5

The Examples dispersed and dispensed well.

Examples 4 to 7 an and P

Compositions having a range of fabric softening compound to solubilising agent ratios were prepared according to the either of the methods described above in Preparation of Examples. The softening performance was determined. 95/27771

18

Softening Results

HT TMAPC:*L5351 Softness Score (wt ratio)

A 5:0 2.5

4 4:1 2.75

5 3:2 3.0

6 2:3 3.25

7 1:4 5.5

B 0:5 7.25

Fatty acid amido alkyl betaine ex Th Goldschmidt

Compositions 4 to 7 all exhibited good softening performance and good stability. Composition A set under a freeze/thaw test as described under Test III above.

Examples 8 to 14 and C to F

The compositions were prepared by either one of the methods described for Preparation of Examples.

8 9 10 11 12 13 14 C D E F

HT TMAPC 9 7.5 9 7.5

DEQA 7.5 9 7.5

*Arosurf 9 7.5 9 7.5 TA-100

10 DDAO 6 7.5 7.5 6 7.5

Tegobetaine 6 7.5 6 7.5 6 7.5 L 5351

Perfume 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 I

Water 84.1 84.1 84.1 84.1 84.1 84.1 84.1 84.1 84.1 84.1 84.1

15

DDAO = N,N-dimethyl dodecyl amine-N-oxide ex Flucka

L5351 ex Th Goldschmidt

*distoaryl dimethyl ammonium chloride ex Sherex

20

The storage stability of compositions 8 to 14 was determined by storing the compositions under a variety of conditions including a freeze/thaw regime and measuring the viscosity thereof using a Carri-med rheometer at a shear rate of 110 sec^"1. The results are shown below.

The comparative compositions all set or the components separated illustrating poor stability.

The compositions according to the invention all exhibited acceptable storage stability and did not set under the freeze/thaw regime.

Compositions were analysed in accordance with Test 1 described above and were filtered by being consecutively passed through filters of pore sizes 1 μm, 0.45 μm and 0.2 μm to achieve separation. The cationic material remaining was measured by standard titration.

Nonionic used % Cationic remaining 0.2um filter

8 85

9 90

10 97.1

11 94.9

12 86.3

13 84.6

14 94.1

C 50

D 56

E 16

F Too viscous to filter

The compositions were analysed under Tests II and III described above. The viscosities were measured on a Carri-med rheometer at shear rate of 110 sec^"1.

Product Initial Test II Test III Viscosity/ mPas 24 hrs @ F/Thaw / mPas 60°C / mPas

8 3.2 3.4 3.8

9 6.8 4.1 2.7

10 2.7 1.9 2.8

11 2.6 2.0 1.8

12 2.0 4.2 3.5

13 2.6 2.5 2.1

14 1.8 1.7 2.3

C 7.4 Separated

D Separated Separated

E 57 95

F 111 Separated

The softening effect of compositions was determined. The results are shown below using a 5% solution of fabric softening compound and solubilising agent (ratio 3:2) ..

Softening appraisal

Sample Softness Std.

5% HEQ 5:0 3.0

10 2.75

13 3.75

Claims

1) A fabric softening composition comprising i) a substantially water insoluble fabric softening compound comprising a compound having two C_12-22 alkyl or alkenyl groups connected to a quaternary ammonium head group via at least one ester link or a quaternary ammonium compound comprising of a single chain with an average chain length equal to or greater than C₂₀ and; ii) a solubilising agent comprising an amphoteric surfactant and optionally a non-surfactant co- surfactant; characterised in that when the fabric softening composition is diluted in water to a concentration of 5 wt % of (i) and (ii), at least 70 wt% of the fabric softening compound is in solution.

2) A fabric softening agent according to claim 1 in which the quaternary ammonium compound comprises a substantially water insoluble fabric softening compound comprising a compound having two C₁₂.₂₂ alkyl or alkenyl groups connected to a quaternary ammonium head group via at least one ester link.

3) A fabric softening composition according to claim 1 or claim 2, in which the solubilising agent comprises an amphoteric surfactant and a non-surfactant co- solubiliser.

4) A fabric softening composition according to any preceding claim in which the weight ratio of solubilising agent to fabric softening compound is greater than 1:6. 5) A fabric softening composition according to claim 4 in which the ratio of solubilising agent to fabric softening compound within the range from 2:3 to 4:1.

6) A fabric softening composition according to any preceding claim in which the fabric softening compound has a solubility of less than 1 x 10^"3 Wt% in demineralised water at 22°C.

7) A fabric softening composition according to any preceding claim in which the softening compound is selected from 1,2 bis [hardened tallowoyloxy] -3- trimethylammonium propane chloride and di (tallowylethyleneoxy) dimethyl ammonium chloride.

8) A fabric softening composition according to any preceding claims in which the level of solubilising agent is greater than 10 wt% of the total composition.

9) A fabric softening composition according to any preceding claim in which the composition is in the form of in the form of self-size-limiting molecular aggregates.

10) A fabric softening composition according to any preceding claim which is in liquid form.

11) A fabric softening composition according to any one of claims 1 to 9 which is granular or powdered.

12) Use of self-size-limiting molecule aggregates as a fabric softening composition.