EP0415698A2

EP0415698A2 - Fabric softening composition

Info

Publication number: EP0415698A2
Application number: EP19900309376
Authority: EP
Inventors: Mansur Sultan Mohammadi; Edwin Willis; Peter Graham Montague; Johannes Cornelis Van De Pas
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 1989-08-31
Filing date: 1990-08-28
Publication date: 1991-03-06
Anticipated expiration: 2010-08-28
Also published as: JP2635205B2; ES2071030T3; DE69017316D1; KR910004888A; ES2071030T5; GB8919669D0; KR930007737B1; MY106842A; ZA906971B; JPH03119187A; CA2023950A1; EP0415698B2; AU6196490A; DE69017316T2; AU625206B2; EP0415698A3; DE69017316T3; CA2023950C; EP0415698B1; BR9004321A

Abstract

Fabric-softening composition comprising an aqueous base and one or more fabric-softening materials, said composition having a structure of lamellar droplets dispersed in the aqueous base, said composition also comprising a deflocculating polymer comprising a hydrophilic backbone and one or more hydrophobic side chains.

Description

The present invention relates to fabric-softening compositions, in particular to fabric-softening compositions which comprise one or more fabric-softening materials and, optionally, sufficient dissolved electrolyte to result in a structure of lamellar droplets dispersed in a continuous aqueous phase.
Lamellar droplets are a particular class of surfactant structures which, inter alia, are already known from a variety of references, e.g. H.A.Barnes, 'Detergents', Ch.2. in K.Walter (Ed), 'Rheometry: Industrial Applications', J.Wiley & Sons, Letchworth 1980.
Lamellar fabric-softening compositions are for example known from EP 303 473 (Albright and Wilson). This patent application describes fabric-softening compositions comprising an aqueous base, a cationic fabric softener having two long alkyl or alkenyl groups and dissolved electrolyte to form an optically anisotropic spherulitic composition.
The presence of lamellar droplets in a fabric-softening product may be detected by means known to those skilled in the art, for example optical techiques, various rheometrical measurements, X-ray or neutron diffraction, and electron microscopy.
The droplets consist of an onion-like configuration of concentric bi-layers of molecules of fabric-softening material, between which is trapped water or electrolyte solution (aqueous phase). Systems in which such droplets are nearly of fully close-packed provide a very desirable combination of physical stability and useful flow properties.
The viscosity and stability of the product depend on the volume fraction of the liquid which is occupied by the droplets. Generally speaking, the higher the volume fraction of the dispersed lamellar phase (droplets), the better the stability. However, higher volume fractions also lead to increased viscosity which in the limit can result in an unpourable or gelled product. This results in a compromise being reached. When the volume fraction is around 0.6, or higher, the droplets are just touching (space-filling). This allows reasonable stability with an acceptable viscosity (say no more than 2.5 Pas, preferably no more than 1 Pas at a shear rate of 21s⁻¹). Conductivity measurements are known to provide a useful way of measuring the volume fraction, when compared with the conductivity of the continuous phase.
A complicating factor in the relationship between stability and viscosity on the one hand and, on the other, the volume fraction of the lamellar droplets, is the degree of flocculation of the droplets. When flocculation occurs between the lamellar droplets at a given volume fraction, the viscosity of the corresponding product will increase due to the formation of a network throughout the liquid. Flocculation may also lead to instability because deformation of the lamellar droplets, owing to flocculation, will make their packing more efficient. Consequently, more lamellar droplets will be required for stabilization by the space-filling mechanism, which will again lead to a further increase of the viscosity.
The volume fraction of droplets is increased by increasing the softener concentration, and may be reduced by increasing the electrolyte level, however, flocculation between the lamellar droplets may occur when a certain threshold value of the electrolyte concentration is crossed at a given level of fabric-softening material (and fixed ratio between any different softening components). Thus, in practice, the effects referred to above mean that there is a limit to the amounts of fabric-softening material and electrolyte which can be incorporated whilst still having an acceptable product. In principle, higher levels of fabric-softening materials are desired for convenience and for reduction of costs. Increased electrolyte levels can also be used for better performance, or are sometimes sought for secondary benefits such as carry-over protection.
We have now found that the dependency of stability and/or viscosity upon volume fraction of softening compositions can be favourably influenced by incorporating into the compositions a deflocculating polymer comprising a hydrophilic backbone and one or more hydrophobic side chains.
Accordingly, the present invention relates to a fabric-softening composition comprising an aqueous base and one or more fabric-softening materials, said composition having a structure of lamellar droplets dispersed in the aqueous base, said composition also comprising a deflocculating polymer comprising a hydrophilic backbone and one or more hydrophobic side chains.
The deflocculating polymer allows, if desired, the incorporation of greater amounts of softening materials and/or electrolytes than would otherwise be compatible with the need for a stable, easily dispersable product of acceptable viscosity. It also allows (if desired) incorporation of greater amounts of certain other ingredients to which, hitherto, lamellar dispersions have been highly stability-sensitive.
The present invention allows formulation of stable, pourable products wherein the volume fraction of the dispersed phase is 0.5, 0.6 or higher, but with combinations or concentrations of ingredients not possible hitherto.
The volume fraction of the lamellar droplet phase may be determined by the following method. The composition is centrifuged, say at 40,000 G for 12 hours, to separate the composition into a clear (continuous aqueous) layer, a turbid active-rich (lamellar) layer and (if solids or liquids are suspended) a third layer. The conductivity of the continuous aqueous phase, the lamellar phase and of the total composition before centrifugation are measured. From these, the volume fraction of the lamellar phase is calculated or estimated, using the Bruggeman equation, as disclosed in American Physics, 24, 636 (1035).
Preferably, the viscosity of the aqueous continuous phase is less than 25 mPas, most preferably less than 15 mPas, especially less than 10 mPas, these viscosities being measured using a capillary viscometer, for example an Ostwald viscometer.
In practical terms, i.e. as determining product properties, the term 'deflocculating' in respect of the polymer means that the equivalent composition, minus the polymer, has a significantly higher viscosity and/or becomes unstable. It is not intended to embrace the use of polymers which would increase the viscosity but not enhance the stability of the composition. It is also not intended to embrace polymers which would lower the viscosity simply by a dilution effect, i.e. only by adding to the volume of the continuous phase. Although within the ambit of the present invention, relatively high levels of the deflocculating polymers can be used in those systems where a viscosity reduction is brought about; typically levels as low as from about 0.01% by weight to about 2.0% by weight can be capable of reducing the viscosity at 21 s⁻¹ by up to 2 orders of magnitude.
Especially preferred embodiments of the present invention exhibit less phase separation on storage and have a lower viscosity than an equivalent composition without any of the deflocculating polymer.
Preferred embodiments of the invention exhibit smaller droplet size than an equivalent composition without any of the deflocculating polymer. From US 3 974 076 it is known that smaller droplet sizes enhance fabric softening, but in the past such small droplets were only obtainable by high energy processing.
Without being bound by an particular interpretation or theory, the applicants have hypothesised that the polymers exert their action on the composition by the following mechanism. The hydrophobic side chain(s) could be incorporated only in the outer bi-layer of the lamellar droplets, leaving the hydrophilic backbone over the outside of the droplets and additionally the polymers could also be incorporated deeper inside the droplet.
When the hydrophobic side chains are only incorporated in the outer bi-layer of the droplets, this has the effect of decoupling the inter- and intra-droplet forces, i.e. the difference between the forces between individual softener molecules in adjacent layers within a particular droplet and those between softener molecules in adjacent droplets could become accentuated in that the attractive forces between adjacent droplets are reduced. This will generally result in an increased stability due to less flocculation and a decrease in viscosity due to smaller forces between the droplets resulting in greater distances between adjacent droplets.
When the polymers are incorporated deeper inside the droplets, also less flocculation will occur, resulting in an increase in stability. The influence of these polymers within the droplets on the viscosity is governed by two opposite effects: first the presence of decoupling polymers will decrease the attractive forces between adjacent droplets resulting in greater distances between the droplets, generally resulting in a lower viscosity of the system; second the attractive forces between the layers within the droplets are equally reduced by the presence of the polymers in the droplet, this generally resulting in an increase in the water layer thickness, therewith increasing the lamellar volume of the droplets, therewith increasing the viscosity. The net effect of these two opposite effects may result in either a decrease or an increase in the viscosity of the product.
It is possible in patent specifications relating to aqueous fabric-softening compositions to define the stability of the composition in terms of the volume separation observed during storage for a predetermined period at a fixed temperature. In fact, this can be an over-simplistic definition of what is observed in practice. Thus, it is appropriate here to give a more detailed description.
For lamellar droplet dispersions, where the volume fraction of the lamellar phase is below 0.6 and the droplets are flocculated, instability is inevitable and is observed as a gross phase separation occurring in a relatively short time. When the volume fraction is below 0.6 but the droplets are not flocculated, the composition may be stable or unstable. When it is unstable, a phase separation occurs at a slower rate than in the flocculated case and the degree of phase separation is less.
When the volume fraction of the lamellar phase is below 0.6, whether the droplets are flocculated or not, it is possible to define stability in the conventional manner. In the context of the present invention, stability for these systems can be defined in terms of the maximum separation compatible with most manufacturing and retail requirements. That is, the 'stable' compositions will yield no more than 2% by volume phase separation as evidenced by appearance of 2 or more separate phases when stored at 25°C for 21 days from the time of preparation.
In the case of the compositions where the lamellar phase volume fraction is 0.6 or greater, it is not always easy to apply this definition. In the case of the present invention, such systems may be stable or unstable, according to whether or not the droplets are flocculated. For those that are unstable, i.e. flocculated, the degree of phase separation may be relatively small, e.g. as for the unstable non-flocculated systems with the lower volume fraction. However, in this case the phase separation will often not manifest itself by the appearance of a distinct layer of continuous phase but will appear distributed as 'cracks' throughout the product. The onset of these cracks appearing and the volume of the material they contain are almost impossible to measure to a very high degree of accuracy. However, those skilled in the art will be able to ascertain instability because the presence of a distributed separate phase greater than 2% by volume of the total composition will readily be visually identifiable by such persons. Thus, in formal terms, the above-mentioned definition of 'stable' is also applicable in these situations, but disregarding the requirement for the phase separation to appear as separate layers.
Especially preferred embodiments of the present invention yield less than 0.1% by volume visible phase separation after storage at 25°C for 21 days from the time of preparation.
It must also be realised that there can be some difficulty in determining the viscosity of an unstable fabric-softening composition.
When the volume fraction of the lamellar phase is less than 0.6 and the system is deflocculated or when the volume fraction is 0.6 or greater and the system is flocculated, then phase separation occurs relatively slowly and meaningful viscosity measurement can usually be determined quite readily. For all compositions of the present invention it is usually preferred that their viscosity is not greater than 2.5 Pas, most preferably no more than 1.0 Pas, and especially not greater than 750 mPas at a shear rate of 21 s⁻¹.
When the volume fraction of the lamellar phase is less than 0.6 and the droplets are flocculated, then often the rapid phase separation occurring makes a precise determination of viscosity rather difficult. However, it is usually possible to obtain a figure which, whilst approximate, is still sufficient to indicate the effect of the deflocculating polymer in the compositions according to the present invention. Where this difficulty arises in the compositions exemplified hereinbelow, it is indicated accordingly.
The compositions according to the invention may contain only one, or a mixture of deflocculating polymer types. The term 'polymer types' is used because, in practice, nearly all polymer samples will have a spectrum of structures and molecular weights and often impurities. Thus, any structure of deflocculation polymers described in this specification refers to polymers which are believed to be effective for deflocculation purposes as defined hereabove. In practice these effective polymers may constitute only part of the polymer sample, provided that the amount of deflocculation polymer in total is sufficient to effect the desired deflocculation effects. Furthermore, any structure described herein for an individual polymer type, referes to the structure of the predominating deflocculating polymer species and the molecular weight specified is the weight average molecular weight of the deflocculation polymers.
The hydrophilic backbone of the polymer generally is a linear, branched or cross-linked molecular composition containing one or more types of relatively hydrophilic monomer units, possibly in combination with minor amounts of relatively hydrophobic units. The only limitations to the structure of the hydrophilic backbone are that the polymer must be suitable for incorporation in an active-structured aqueous liquid softener composition and the hydrophilic backbone is relatively soluble in water in that the solubility in water of 20°C at a pH of 7.0 is preferably more than 1 g/l, more preferably more than 5 g/l, most preferably more than 10 g/l.
Preferably, the hydrophilic backbone is predominantly linear in that the main chain of the backbone constitutes at least 50% by weight, preferably more than 75%, most preferably more than 90% by weight of the backbone.
The hydrophilic backbone is constituted by monomer units, which can be selected from a variety of units available for the preparation of polymers. The polymers can be linked by any possible chemical link, although the following types of linkages are preferred:

-O-, -
-O-, -C-C-, -
-, -C-N-, -
-N-
Water-soluble monomers suitably employed to form the hydrophilic backbone are for example those which are sufficiently water-soluble to form at least a one weight percent solution when dissolved in water and readily undergo polymerisation to form polymers which are water-soluble at ambient temperature and at a pH of 3.0 to 12.5, preferably more than 1 gram per litre, more preferably more than 5 grams per litre, most preferably more than 10 grams per litre. Exemplary water-soluble monomers include ethylenically unsaturated amides such as acrylamide, methyacrylamide and fumaramide and their N-substituted derivatives such as 2-acrylamido-2-methylpropane sulphonic acid, N-(dimethylaminomethyl) acrylamideas well as N-(trimethylammoniummethyl) acrylamide chloride and N-(trimethylammoniumpropyl) methacrylamide chloride; ethyleneically unsaturated carboxylic acids or dicarboxylic acids such as acrylic acid, maleic acid, methacrylic acid, itaconic acid, fumaric acid, crotonic acid, aconitic acid and citraconic acid; and other ethylenically unsaturated quaternary ammonium compounds such as vinylbenzyl trimethyl ammonium chloride; hydroxyethyl(meth) acrylate; sulphoalkyl esters of unsaturated carboxylic acids such as 2 sulphoethyl methacrylate; aminoalkyl esters of unsaturated carboxylic acids such as 2-aminoethyl methacrylate, dimethyl aminoethyl (meth)acrylate, diethyl aminoethyl (meth)acrylate, dimethyl aminomethyl (meth)acrylate, diethyl aminomethyl (meth)acrylate), and their quaternary ammonium salts; vinyl or allyl amines such as vinyl pyridine and vinyl morpholine or allylamine; diallyl amines and diallyl ammonium compounds such as diallyl dimethyl ammonium chloride; vinyl heterocyclic amides such as vinyl pyrrolidone; sodium alkyl sulphonate; vinyl aryl sulphonates such as vinylbenzyl sulphonate; vinyl alcohol obtained by the hydrolysis of vinyl acetate; acrolein; allul alcohol; vinyl acetic acid; sodium vinyl sulphonate; sodium allyl sulphonate, as well as the salts of the foregoing monomers. These monomers may be used singly or as mixtures thereof.
Optionally, the hydrophilic backbone may contain small amounts of relatively hydrophobic units, e.g. those derived from polymers having a solubility of less than 1 g/l in water, provided that the overall solubility of the hydrophilic polymer backbone still satisfies the solubility requirements as specified here above. Examples of relatively water-insoluble polymers are polyvinyl acetate, polymethyl methacrylate, polyethyl acrylate, polyethylene, polypropylene, polystyrene, polybutylene oxide, polypropylene oxide, polyhydroxypropyl acrylate.
Suitable hydrophobic monomers for forming the side chains generally include those which are (1) water-insoluble, i.e. less than 0.2 weight part of the hydrophobic monomer will dissolve in 100 weight parts water and (2) ethylenically unsaturted compounds having hydrophobic moieties. The hydrophobic moieties (when isolated from their polymerisable linkage) are relatively water-insoluble, preferably less than 1 g/l, more preferably less than 0.5 g/l, most preferably less than 0.1 g/l at ambient temperature and a pH of 3.0 to 12.5.
The hydrophobic moieties preferably have at least 5 carbon atoms and are most preferably pendant organic groups having hydrophobicities comparable to one of the following: aliphatic hydrocarbon groups having at least five carbons such as C₅ to C₅₀ alkyls and cycloalkyls; polynuclear aromatic hydrocarbon groups such as naphthyls; alkylaryls wherein the alkyl group has one or more carbons; haloalkyls of 5 or more carbons, preferably perfluoroalkyls; polyalkyleneoxy groups wherein alkylene is propylene or high alkylene and there is at least one alkyleneoxy unit per hydrophobic moiety; and siloxane moieties. Exemplary hydrophobic monomers include the higher alkyl esters of alpha, beta-ethylenically unsaturated carboxylic acids such as dodecyl acrylate, dodecyl methacrylate, tridecyl acrylate, tridecyl methacrylate, tetradeculacrylate, tetradecylmethacrylate, octadecyl acrylate, octadecyl methacrylate, octyl half ester of maleic anhydride, doictyl diethyl maleate, and other alkyl esters and half esters derived from the reactions of alkanols having from 5 to 50 carbon atoms with ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, itaconic acid and aconitic acid; alkylaryl esters of ethylenically unsaturated carboxylic acids such as nonyl- -phenyl methacrylate, dodecyl- -phenyl acrylate and dodecyl- -phenyl methacrylate; N-alkyl, ethylenically unsaturated amides such as N-octadecyl acrylamide; N-octadecyl methacrylamide, N,N-dioctyl acrylamide and similar derivatives thereof, -olefins such as octene-1, decene-1, dodecene-1 and hexadecene-1; vinyl alkylates wherein alkyl has at least 4 carbon atoms such as vinyl laurate and vinyl stearate; vinyl alkyl ethers such as dodecyl vinyl ether and hexadecyl vinyl ether; N-vinyl amides such as N-vinyl lauramide and N-vinyl stearamide; and alkylstyrenes such as t-butyl styrene. The hydrophobic monomer may be used single or mixtures thereof may be employed. The ratio of hydrophilic to hydrophobic monomers may vary from about 500:1 to 5:1. The weight average molecular weights (Mw.) of the resultant polymers vary from 500 to 500,000 or above when measured by gel permeation chromatography using polyacrylate standards, or by standard viscosity (SV) measurements using polyacrylate standards.
Products of the invention preferably comprise polymers of the general formula:
wherein z is 1; (x + y):z is from 5:1 to 500:1; in which the monomer units may be in random order; y being from 0 up to a maximum equal to the value of x; and n is at least 1;
R¹ represents -CO-O, -O-, -O-CO-, -CH₂, -CO-NH- or is absent;
R² represents from 1 to 50 independently selected alkyleneoxy groups, preferably ethylene oxide or propylene oxide groups, or is absent, provided that when R³ is absent and R⁴ represents hydrogen, then R² must contain an alkyleneoxy group with at least 3 carbon atoms;
R³ represents a phenylene linkage, or is absent;
R⁴ represents hydrogen or a C₅₋₂₄ alkyl or C₅₋₂₄ alkenyl group, with the provisos that:

a) when R¹ represents -O-CO-, R² and R³ must be absent and R⁴ must contain at least 5 carbon atoms and
b) when R² is absent, R⁴ is not hydrogen and R³ is absent then R⁴ must contain at least 5 carbon atoms;

Another class of polymers in accordance with the present invention comprises those of formula II:
wherein:
Q² is a molecular entity of formula IIa:
wherein z and R¹⁻⁶ are as defined for formula (I);
A¹⁻⁴ are as defined for formula (I);
Q¹ is a multifunctional monomer, allowing the branching of the polymer, wherein the monomers of the polymer may be connected to Q¹ in any direction, in any order, therewith possibly resulting in a branched polymer. Preferably Q¹ is trimethyl propane triacrylate (TMPTA), methylene bisacrylamide or divinyl glycol;
n and z are as defined above; v is 1; and (x + y + p + q + r):z is from 5:1 to 500:1; in which the monomer units may be in random order; and preferably either p and q are zero, or r is zero;
R⁷ and R⁸ represent -CH₃ or -H;
R⁹ and R¹⁰ represent substituent groups such as amino, amine, amide, sulphonate, sulphate, phosphonate, phosphate, hydroxyl, carboxyl and oxide groups, or (C₂H₄O)_tH, wherein t is from 1-50, and wherein the monomer units may be in random order. Preferably they are selected from -SO₃Na, -CO-O-C₂H₄, -OSO₃Na, -CO-NH-C(CH₃)₂-CH₂-SO₃Na, -CO-NA₂, -O-CO-CH₃, -OH. In any particular sample of polymer material in which polymers of formulae I and II are in the form of a salt, usually some polymers will be full salts (A¹-A⁴ all other than hydrogen), some will be full acids (A¹-A⁴ all hydrogen) and some will be part-salts (one or more A¹-A⁴ hydrogen and one or more other hydrogen).
The salts of the polymers of formulae I and II may be formed with any organic or inorganic cation defined for A¹-A⁴ and which is capable of forming a water-soluble salt with a low molecular weight carboxylic acid. Preferred are the alkali metal salts, especially of sodium or potassium.
Another class of polymers in accordance with the present invention comprises those of formula III:
wherein Q³ is derived from a monomeric unit IIIa comprising:
Q⁴ is derived from the molecular entity IIIb:
and Q⁵ is derived from a monomeric unit IIIc:
R¹-R⁶ are defined as in formula I; (a + b + c): Q⁴ is from 5:1 to 500:1, in which the monomer units may be in random order, a, b, c, d, e, f, g, h may be an integer or zero, n is at least 1;
B¹, B², B³, B⁴ are organic or inorganic anions;
w is zero to 4;
R¹¹ and R^11* are independently selected from hydrogen or C₁-C₄ alkyl; and
R¹² is independently selected from C₅ to C₂₄ alkyl or alkenyl, aryl cycloalkyl, hydroxyalkyl or alkoxyalkyl.
The anions represented by B¹, B², B³, B⁴ are exemplified by the halide ions, sulphate, sulphonate, phosphate, hydroxide, borate, cyanide, carbonate, bicarbonate, thiocyanate, sulphide, cyanate, acetate and the other common inorganic and organic ions. Preferred anions are chloride and methosulphate.
Another class of polymers in accordance with the present invention comprise those of formula IV.
where R¹- R⁶ are defined as in formula I, R^6* represents H or C₁₋₄ alkyl, z is 1 and j:z is from 5:1 to 500:1, in which the monomer units may be in random order, and n is at least 1;
R¹³ represents -CH₂-, -C₂H₄-, -C₃H₆ or is absent.
R¹⁴represents from 1 to 50 independently selected alkyleneoxy groups, preferably ethylene oxide groups, or is absent.
R₁₅ represents -OH or hydrogen.
The general formulae I, II, III and IV are to be construed as including those mixed copolymer forms wherein, within a particular polymer molecule where n is 2 or greater, R¹ - R¹⁵ differ between individual monomer units therein.
For the polymers of formula I, II and IV and their salts, it is preferred to have a weight average molecular weight in the region of from 500 to 500,000, preferably 1000 to 200,000 more preferably from 1500 to 50,000 when measured by GPC using polyacrylate standards. For the purposes of this definition, the molecular weights of the standards are measured by the absolute intrinsic viscosity method described by Noda, Tsoge and Nagasawa in Journal of Physical Chemistry, Volume 74, (1970), pages 710-719.
It is difficult to determine accurately the molecular weight distribution of polymers of Formula III, because of the highly cationic nature of these polymers and their subsequent adsorption on the GPC columns. Instead, a measure of molecular weight can be made by measuring a standard viscosity (S.V.), determined at 15.0% solids, 23°C in a 1.0 molar sodium chloride solution using a Brookfield Synchro-lectric (R) viscometer, Model LVT with an LCP adaptor, at a speed of 60 RPM. It is preferred to have a polymer with an S.V. from 1 to 100 mPas, more preferably from 2-50 mPas, most preferably 3-25 mPas.
Empirically it has been found that the following relationship between SV and mW (polyacrylamate basis) exists:
log₁₀ MW = 1.4 log₁₀ SV + 2.5
Preferably the polymers for use in compositions of the present invention are prepared by the method as described in UK Patent application No. 8813966.2.
Generally, the deflocculating polymer will be used at from 0.01% to 5.0% by weight in the composition, most preferably from 0.1% to 2.0%.
Although many softener materials form lamellar dispersions of softener in water alone, in some cases it is preferred for the aqueous continuous phase to contain dissolved electrolyte. As used herein, the term electrolyte means any ionic water-soluble material. However, in lamellar dispersions, not all the electrolyte is necessarily dissolved but may be suspended as particles of solid because the total electrolyte concentration of the liquid is higher than the solubility limit of the elctrolyte. Mixtures of electrolytes also may be used, with one or more of the electrolytes being in the dissolved aqueous phase and one or ore being substantially only in the suspended solid phase. Two or more electrolytes may also be distributed approximately proportionally, between these two phases. In part, this may depend on processing, e.g. the order of addition of components.
The only restriction on the total amount of softener material and electrolyte (if any) is that in the compositions of the invention, together they must result in formation of an aqueous lamellar dispersion. Thus, within the ambit of the present invention, a very wide variation in softener types and levels is possible. The selection of softener types and their proportions, in order to obtain a stable liquid with the required structure will be fully within the capability of those skilled in the art.
Compositions of the present invention preferably comprise from 1 to 80% by weight of fabric-softening materials, more preferably from 10 to 70% by weight, most preferably from 20 to 60% by weight of the composition. The fabric-softening materials may be selected from cationic, nonionic, amphoteric or anionic fabric-softening materials. The level of dissolved electrolyte is typically from 0 to 20%, more preferred from 0.01 to 10%, most preferred from 0.1 to 5% by weight of the composition.
Suitable amphoteric fabric-conditioning material for use in a composition according to the invention are fabric-substantive amphoteric materials forming a particulate dispersion at a concentration of less than 1g/l at at least one temperature between 0 and 100°C, preferably at at least one temperature between 10 and 90°C, more preferably between 20 and 80°C. For the purpose of this invention a fabric-substantive amphoteric material is preferably an amphoteric or zwitterionic tertiary or quaternary ammonium compound having either one single long hydrocarbyl side chain or two long hydrocarbyl chains. From these compounds the use of amphoteric or zwitterionic ammonium compounds having two long hydrocarbyl chains is particularly preferred for many reasons including costs, ease of processing and better stability and performance. Suitable amphoteric materials are for example disclosed in EP 326 213.
In this specification the expression hydrocarbylchain refers to linear or branched alkyl or alkenyl chains optionally substituted or interrupted by functional groups such as -OH, -O-, -CONH-, -COO-, etc.
Preferably the amphoteric fabric-substantive materials are water insoluble and have a solubility in water at pH 2.5 at 20°C of less than 10 g/l.
The HLB of the amphoteric fabric-substantive material is preferably less than 10.0.
Suitable cationic fabric-softener materials for use in a composition according to the present invention are cationic materials which are water-insoluble in that the material has a solubility in water at pH 2.5 and 20°C of less than 10 g/l. Highly preferred materials are cationic quaternary ammonium salts having two C₁₂₋₂₄ hydrocarbyl chains.
Well-known species of substantially water-insoluble quaternary ammonium compounds have the formula:
wherein R₁ and R₂ represent hydrocarbyl groups from about 12 to about 24 carbon atoms; R₃ and R₄ represent hydrocarbyl groups containing from 1 to about 4 carbon atoms; and X is an anion, preferably selected from halide, methosulphate and ethyl sulphate radicals.
Representative examples of these quaternary softeners include ditallow dimethyl ammonium chloride; ditallow dimethyl ammonium methyl sulphate; dihexadecyl dimethyl ammonium chloride; di(hydrogenated tallow) dimethyl ammonium methyl sulphate; dihexadecyl diethyl ammonium chloride; di(coconut) dimethyl ammonium chloride. Ditallow dimethyl ammonium chloride, di(hydrogenated tallow) dimethyl ammonium chloride, di(coconut) dimethyl ammonium chloride and di(coconut) dimethyl ammonium methosulphate are preferred.
Suitable materials also include dialkyl ethoxyl methyl ammonium methosulphate based on soft fatty acid, dialkyl ethoxyl methyl ammonium methosulphate based on hard fatty acid, and a material in which R₃ and R₄ represent methyl, R₁ is C₁₃₋₁₅ R₂ is CH₂CH₂OCOR, where R is stearyl, and X is methosulphate. Ditallow dimethyl ammonium chloride, di(hydrogenated tallow alkyl) dimethyl ammonium chloride, di(coconut alkyl) dimethyl ammonium chloride and di(coconut alkyl) dimethyl ammonium methosulfate are preferred.
Other preferred cationic compounds include those materials as disclosed in EP 239,910 (P&G), which is included herein by reference.
Other preferred materials are the materials of formula:
R₅ being tallow, which is available from Stepan under the tradename Stepantex VRH 90,
where R₈,R₉ and R₁₀ are each alkyl or hydroxyalkyl groups containing from 1 to 4 carbon atoms, or a benzyl group. R₆ and R₇ are each an alkyl or alkenyl chain containing from 11 to 23 carbon atoms, and X⁻ is a water-soluble anion. These materials and their method of preparation are described in US 4 137 180 (LEVER BROTHERS).
Another class of preferred water-insoluble cationic materials are the hydrocarbylimidazolinium salts believed to have the formula:
wherein R₁₃ is a hydrocarbyl group containing from 1 to 4, preferably 1 or 2 carbon atoms, R₁₁ is a hydrocarbyl group containing from 8 to 25 carbon atoms, R₁₄ is an hydrocarbyl group containing from 8 to 25 carbon atoms and R₁₂ is hydrogen or an hydrocarbyl containing from 1 to 4 carbon atoms and A⁻ is an anion, preferably a halide, methosulphate or ethosulphate.
Preferred imidazolinium salts include 1-methyl-1-(tallowylamido-) ethyl -2-tallowyl-4,5-dihydro imidazolinium methosulphate and 1-methyl-1-(palmitoylamido) ethyl -2-octadecyl-4,5- dihydroimidazolinium chloride. Other useful imidazolinium materials are 2-heptadecyl-1-methyl-1 (2-stearylamido)ethyl-imidazolinium chloride and 2-lauryl-1-hydroxyethyl-1-oleyl-imidazolinium chloride. Also suitable herein are the imidazolinium fabric-softening components of US patent No. 4 127 489, incorporated by reference.
Representative commercially available materials of the above classes are the quaternary ammonium compounds Arquad 2HT (ex AKZO); Noramium M2SH (ex CECA)1 Aliquat 2HT (Trade Mark of General Mills Inc), Stepantex Q185 (ex Stepan); Stepantex VP85 (ex Stepan); Stepantex VRH9O (ex Stepan); Synprolam FS (ex ICI) and the imidazolinium compounds Varisoft 475 (Trade Mark of Sherex Company, Columbus Ohio) and Rewoquat W7500 (Trade Mark of REWO).
The compositions according to the invention may also contain, possibly in addition to the above mentioned softening agents, one or more amine softening materials.
The term "amine" as used herein can refer to

(i) amines of formula:
wherein and R₁₅, R₁₆, R₁₇ are defined as below;
(ii) amines of formula:
wherein R₁₈, R₁₉, R₂₀ and R₂₁, m and n are defined as below.
(iii) imidazolines of formula:
wherein and R₁₁, R₁₂ and R₁₄ are defined as above.
(iv) condensation products formed from the reaction of fatty acids with a polyamine selected from the group consisting of hydroxy alkylalkylenediamines and dialkylenetriamines and mixtures thereof. Suitable materials are disclosed in European Patent Application 199 382 (Procter and Gamble), incorporated herein by reference.

When the amine is of the formula I above, R₁₅ is a C₆ to C₂₄, hydrocarbyl group, R₁₆ is a C₁ to C₂₄ hydrocarbyl group and R₁₇ is a C₁ to C₁₀ hydrocarbyl group. Suitable amines include those materials from which the quaternary ammonium compounds disclosed above are derived, in which R₁₅ is R₁, R₁₆ is R₂ and R₁₇ is R₃. Preferably, the amine is such that both R₁₅ and R₁₆ are C₆-C₂₀ alkyl with C₁₆-C₁₈ being most preferred and with R₁₇ as C₁₋₃ alkyl, or R₁₅ is an alkyl or alkenyl group with at least 22 carbon atoms and R₁₆ and R₁₂ are C₁₋₃ alkyl. Preferably these amines are protonated with hydrochloric acid, orthophosphoric acid (OPA), C₁₋₅ carboxylic acids or any other similar acids, for use in the fabric-conditioning compositions of the invention.
when the amine is of formula II above, R₁₈ is a C₆ to C₂₄ hydrocarbyl group, R₁₉ is an alkoxylated group of formula -(CH₂CH₂O)_yH, where y is within the range from 0 to 6, R_{20y is an alkoxylated group of formula -(CH2}CH₂O)_zH where z is within the range from 0 to 6 and m an integer within the range from 0 to 6, and is preferably 3. When m is 0, it is preferred that R₁₈ is a C₁₆ to C₂₂ alkyl and that the sum total of z and y is within the range from 1 to 6, more preferably 1 to 3. When m is 1, it is preferred that R₁₈ is a C₁₆ to C₂₂ alkyl and that the sum total of x and y is within the range from 3 to 10.
Representative commercially available materials of this class include Ethomeen (ex Armour) and Ethoduomeen (ex Armour).
Preferably the amines of type (ii) or (iii) are also protonated for use in the fabric-conditioning compositions of the invention.
When the amine is of type (iv) given above, a particularly preferred material is:
where R₂₂ and R₂₃ are divalent alkenyl chains having from 1 to 3 carbons atoms, and R₂₄ is an acyclic aliphatic hydrocarbon chain having from 15 to 21 carbon atoms. A commercially available material of this class is Ceranine HC39 (ex Sandoz).
Another class of polymers in accordance with the present invention comprise those of formula IV
where R¹-R⁶ are defined as in formula I, Z is 1 and j:z is from 5:1 to 500:1, in which the monomer units may be in random order, and n is at least 1;
R¹³ represents -CH₂-, -C₂H₄-, -C₃H₆- or is absent.
R¹⁴ represents from 1 to 50 independently selected alkyleneoxy groups, preferably ethylene oxide groups, or is absent.
R₁₅ represents -OH or hydrogen.
Compositions according to the present invention preferably have a pH of less than 6.0, more preferred less than 5.0, especially from 1.5 to 4.5, most preferred from 2.0 to 4.0.
The compositions can also contain one or more optional ingredients selected from non-aqueous solvents such as C₁-C₄ alkanols and polyhydric alcohols, pH-buffering agents such as weak acids, e.g. phosphoric, benzoic or citric acids, re-wetting agents, viscosity modifiers, aluminium chlorohydrate, antigelling agents, perfumes especially body odour reducing perfumes, perfume carriers, hydrocarbons, fluorescers, colourants, hydrotropes, antifoaming agents, antiredeposition agents, enzymes, optical brightening agents, opacifiers, stabilisers such as guar gum and polyethylene glycol, anti-shrinking agents, anti-wrinkle agents, silicones, soil-release agents, antioxidants, anti-corrosion agents, preservatives such as Bronopol (Trade Mark), a commercially available form of 2-bromo-2-nitropropane-1,3-diol, to preserve the fabric treatment composition, dyes, bleaches and bleach precursors, drape-imparting agents, antistatic agents and ironing aids.
These optional ingredients, if added, are each present at levels up to 5% by weight of the composition.
The invention will be further illustrated by means of the following examples.

Examples I - XII

In examples I-XII the following polymers are used. Each polymer is obtained from National Starch and Chemical Ltd, Speciality Polymers Division as an aqueous solution of from 30-60% by weight solids level. All percentages for the polymer refer to 100% active polymers.

Basic Structures of Polymers: General Formula I
wherein R1 = COO, R2 is absent, R3 is absent, R5 = H, R6 = CH3 and y = 0 and A¹ = H.

Polymer	Al	x	R4	z	SV mPas
433/57	H	10	C18H37	1	3.9

Basic Structures of Polymers: General Formula II
wherein R8 = H, R = O, v = 1;
In Q2; x = y = 0, R1 = COO, R2, R3 absent, R5 = H, R6 = CH3.

Polymer	R10	q	R7	R9	p	R4	SV mPas
433/64	CONH₂	20	-	-	0	C12H25	5.6
433/66	COOC₂H₄OH	7.5	H	SO3Na	2.5	C12H25	5.3
433/63	CONH₂	20	-	-	0	C₁₈H₃₇	6.5
433/59	CONH₂	10	-	-	0	C₁₈H₃₇	4.8
442/104	COOC₂H₄OH	10	-	-	0	C₁₂H₂₅	4.1

Basic Structures of polymers: General Formula III
wherein b = c = 0, R6 = CH₃ d = i.
In IIIa, R11 = H, R11* = CH3, B2 = C1.
In IIIb, e = 1, f = g = h = i = 0, R1 = COO, R3 is absent, R5 = H, B3 = C1.

Polymer	a	d	R4	R6	SV mPas
422/60	10	1	CH₂(C₂H₅) C₅H₁₁	H	-
438/153	10	1	C₁₂H₂₅	CH₃	3.3
428/90	25	1	C₁₂H₂₅	CH₃	12.5
10425/157	25	1	C₁₂H₂₅	CH₃	12.9
425/167	25	1	C₁₂H₂₅	CH₃	19.4
425/169	10	1	C₁₂H₂₅	CH₃	5.4
425/176	15	1	C₁₂H₂₅	CH₃	8.0
425/183	5	1	C₁₂H₂₅	CH₃	4.5

Basic Stuctures of Polymers: General Formula IV
Wherein R₁ = 100, R₂ and R₃ are absent, R₆ = CH₃, R₁₃ is absent.

Polymer	R₁₄	R₁₅	R₄	j	Z	SV mPas
433/65	C₂H₄O	H	C₁₂H₂₅	25	1	6.9

Example I

Fabric-softening compositions were made by adding the deflocculating polymer and the electrolyte to water under stirring, followed by adding the softening material which has been preheated to 50°C. The fabric-softening material was Arquad 2T (a dimethyl ditallow ammonium chloride = DMDTAC ex Atlas). The pH of the compositions was adjusted to 4.0 with orthophosphoric acid.
The following compositions were obtained:

Ingredient A B C

% by weight

DMDTAC* 30 30 30

CaCl₂ (1 M) 11.9 11.9 -

Polymer 425/169 0.25 0.05 -

Water balance

* preheated to remove solvent
Compositions A and B were stable fabric-softening compositions which did not show any visible phase separation upon storage for several weeks at ambient temperature. They had a viscosity of about 400 mPas at 21 s⁻¹ and had a good dispersibility in water of ambient temperature. Composition C was gel-like, translucent and of unacceptable dispersibility in water.

Example II

The following compositions were prepared as in Example I, the fabric-softener material being an ester-linked quaternary ammonium material Stepantex VRH 90 which had been preheated to remove any solvent present.

Ingredient A B C D

% by weight

Stepantex VRH 90* 30 30 30 30

NaCl 1.8 2.0 2.0 2.0

Dobanol 91-6 ** 1.0 1.5 1.5 1.0

Polymer 425/183 - 0.11 0.2 0.1

CaCl₂ (1 M) - - - 0.92

* preheated to remove solvent

** C_9-11 alcohol ethoxylated with 6EO groups (ex Shell)
Formulations A-D were stable fabric-softening compositions which did not show any visible phase separation upon storage for several weeks at ambient temperature. Compositions B-D were of acceptable viscosity and were well dispersible in water of ambient temperature. Composition A was unacceptably viscous and of poor dispersibility.

Example III

The following compositions were prepared as in Example I.

Ingredient	A	B	C	D
	% by weight
DMDTAC **	24	24	24	24
Glycerol monostearate	6	-	6	6
Cithrol 2 M S *	-	6	-	-
Polymer 425/169	2.0	2.0	-	-
Polymer 425/183	-	-	2.0	-
Dobanol 91-6	2.0	2.0	2.0	2.0
CaCl₂ (1 M)	11.9	11.9	11.9	11.9
Water	balance

* polyethylene ex Croda of molecular weight 200
** preheated to remove solvent

Compositions A-D were stable fabric-softening compositions which did not show any visible phase separation upon storage at ambient temperature. Compositions A-C had a viscosity of about 400 mPas at 21s⁻¹ and were of good dispersibility. Composition D was unacceptably viscous.

Example IV

The following formulations were made by adding the citrate to the water of ambient temperature and subsequently adding the fabric-softening material. The polymer was added as the last ingredient at ambient temperature.

Ingredient A B C

% by weight

DMDTAC ** 50 50 50

Water 48 48 50

Trisodium citrate 2H₂O 2.0 2.0 2.0

Polymer 425/167* 0.3 - -

Polymer 428/90* - 0.3 -

* On top of formulation

** 70% active.20% isopropylalcohol.10% water
Compositions A and B were more stable than composition C. Compositions A and B were pourable milky liquids, while compositions C was a semi-translucent to milky gel which showed 12% by volume phase separation upon one-day storage at ambient temperature.

Example V

The following formulations were made as in Example I.

Ingredient A B C

% by weight

Trisodium citrate 2H₂O 1.96 1.96 1.96

Polymer 425/169 0.06 - -

Polymer 425/183 - 0.06 -

DMDTAC* 47.8 47.8 47.8

Water balance

* 70% active.20% isopropylalcohol.10% water
Compositions A and B were stable, pourable milky liquids. Composition C was an unstable semi-translucent to milky gel.

Example VI

The following formulations were made as in Example I.

Ingredient	A	B	C	D
	% by weight
STP	1.96	1.96	1.96	1.96
DMDTAC *	47.8	47.8	47.8	47.8
Polymer 425/167	0.25	-	-	-
Polymer 425/157	-	0.25	-	-
Polymer 425/176	-	-	0.25	-
Water	balance

* 70% active.20% isopropylalcohol.10% water

Composition D was a pourable semi-translucent liquid which separated into two translucent layers with in 2 days. Compositions A-C were pourable milky liquids which were of acceptable stability.

Example VII

The following formulations were made as in Example I.

Ingredient	A	B	C	D
	% by weight
DMDTAC *	49.2	49.2	49.2	49.2
CaCl₂, 2H₂O	0.98	0.98	0.98	0.98
Polymer 425/167	0.3	-	-	-
Polymer 425/157	-	0.3	-	-
Polymer 428/90	-	-	0.3	-
Water	balance

* 70% active.20% isopropylalcohol.10% water

Composition D was a milky pourable liquid which separated into two layers in minutes. Compositions A-C were of acceptable stability, pourable and did not show any discolouration upon storage.

Example VIII

The following fabric softening compositions were prepared as in Example 1. All compositions were stable translucent product having a viscosity of about 250 mPas at 21 s⁻¹ and were well dispersable in water of ambient temperature.

Ingredient	A	B	C	D	E
DMDTAC *	48.7	48.7	48.4	48.5	48.7
Trisodium citrate 2H₂O	1.95	1.95	1.0	1.5	1.0
Polymer 433/63	0.3	-	0.7	-	-
Polymer 433/65	-	0.3	-	-	-
Polymer 433/59	-	-	-	0.7	-
Polymer 433/57	-	-	-	-	0.7
Water	balance

* 70% active.20% isopropylalcohol.10% water

Example IX

The following fabric softening compositions were prepared as in Example I. All compositions were stable, milky to semi-translucent products having a viscosity of about 400 mPas at 21 s⁻¹. The dispersability of the products in water of ambient temperature was good.

Ingredient A B C D

% by weight

DMDTAC * 49.0 49.0 49.3 49.2

STP 1.5 1.0 - -

Polymer 433/63 0.3 - 0.3 -

Polymer 433/57 - 0.3 - 0.3

CACl₂.H₂O - 0.24 0.66 0.8

Water balance

* 70% active.20% isopropylalcohol.10% water

Example X

The following compositions were prepared as in Example I. All products were stable and of acceptable viscosity and dispersability.

Ingredient	A	B	C	D	E	F	G
	% by weight
DTTMAPC *	21	21	22.5	22.5	22.5	22.5	20
DMDTAC **	-	-	7.5	7.5	7.5	7.5	-
NaCl	2.0	2.0	2.0	2.0	2.0	2.0	2.0
Polymer 433/63	0.5	-	0.5	-	-	-	-
Polymer 433/64	-	0.5	-	0.5	-	-	-
Polymer 433/65	-	-	-	-	0.5	-	-
Polymer 433/66	-	-	-	-	-	0.5	-
Polymer 433/183	-	-	-	-	-	-	2.0
Dobanol 91-6	-	-	2.0	-	1.5	-	2.0
CACl₂ (IM)	-	-	2.0	-	-	-	1.0
Silicone anti-foam	-	-	-	-	-	1.0	-
Water	balance

* 70.30 mixture of 1,2 ditallow oxytrimethyl ammonium propane chloride and 1 - tallow 2 - hydroxy trimethyl ammonium propane chloride.
** As in example I.

Example XI

Fabric softening compositions were made by adding calcium chloride to water, then adding a heated premix of fabric softener and nonionic and finally adding the polymer. The fabric softening material was Arquad 2HT (a dimethyl dihydrogenated tallow ammonium chloride DMDHTAC) ex Atlas. The nonionic was Genopol T050 a tallow alcohol ethoxylated with 5 moles of ethylene oxide ex Hoechst. The pH was adjusted to between 3.5 and 4 with orthophosphoric acid.
The following compositions were obtained:

Ingredient A B

DMDHTAC 22.35 18.0

Nonionic 3.0 3.0

CaCl₂ 5.4 -

Polymer 438/153 0.5 0.5

Water balance balance
Compositions A and B were stable fabric-softening compositions which did not show any visible phase separation on storage for several weeks at ambient temperature. They had a viscosity of about 400 mPas at 21s⁻¹.

Example XII

The following formulations were made by dispersing the polymer in an aqueous base before adding the fabric softener.

Ingredient A B

DMDHTAC 7.76 7.76

Polymer 442/104 0.1 0.25

CaCl₂ 0.005 0.06

Water balance balance

These formulations were found to have droplet sizes around 1 micron when measured by phase contrast microscopy. Formulations not containing polymer generally have droplet sizes of at least 3 microns.

Claims

1. Fabric-softening composition comprising an aqueous base and one or more fabric-softening materials, said composition having a structure of lamellar droplets dipsersed in the aqueous base, said composition also comprising a deflocculating polymer comprising a hydrophilic backbone and one or more hydrophobic side chains.

2. Fabric-softening composition according to claim 1, wherein the deflocculating polymer is of the general formula (I) as defined hereinabove.

3. Fabric-softening composition according to claim 1, wherein the deflocculating polymer is of the general formula (II) as defined hereinabove.

4. Fabric-softening composition according to claim 1, wherein the deflocculating polymer is of the general formula (III) as defined hereinabove.

5. Fabric-softening composition according to claim 1, wherein the deflocculating polymer is of the general formula (IV) as defined hereinabove.

6. Fabric-softening composition according to any of the preceding claims, comprising from 0.1 to 2.0% by weight of the composition of deflocculating polymers.

7. Fabric-softening composition according to any of the preceding claims, wherein the softener material comprises a cationic fabric-softening material.

8. Fabric-softening composition according to any of the preceding claims, comprising from 20-60% by weight of fabric-softening material.

9. Fabric-softening composition according to any of the preceding claims, also comprising from 0.1-5.0% by weight of dissolved electrolyte.

10. Fabric-softening composition according to any of the preceding claims, having a pH of less than 6.0.

11. Process for the preparation of a fabric softening composition according to one or more of the claims 1-10, wherein the deflocculating polymer is dispersed in the aqueous base before addition of the fabric softening material thereto.

12. Method of treating fabrics comprising the contacting of fabrics with an aqueous liquor comprising a fabric-softening composition according to any of the preceding claims at a concentration of from 1 to 1000 ppm of fabric-softener materials in the aqueous liquor.

13. Use of a deflocculating polymer comprising a hydrophilic backbone and one or more hydrophobic side chains in a fabric softening composition comprising an aqueous base and one or more fabric-softening materials, said composition having a structure of lamellar droplets dispersed in the aqueous base for producing a fabric softening composition with a viscosity below 2.5 Pas.