CA2343137C - Use of cationic materials and compositions - Google Patents

Abstract

A cationic material, preferably a cationic fabric conditioning surfactant, i s used to reduce skin irritancy of material extractable from a fabric. Preferably the cationic material neutralises free anionic residues present on a fabric. The material or composition may form chemical complexes with the anionic residues and can be used to hinder the subsequent release of the residues from the fabric. The invention also relates to the use of a cationic fabric conditioning composition and a fabri c laundering process in which the cationic material or fabric conditioning composition is used.

Description

USE OF CATIONIC MATERIALS AND COMPOSITIONS
Technical Field This invention relates to the use of cationic materials and compositions, in particular cationic fabric conditioning materials and compositions, to reduce skin irritancy. It also relates to a fabric laundering process which includes such use.

Background Art Detergents used to launder fabrics can leave residues, e.g.
anionic materials, on the fabrics after the wash. If left untreated, or unremoved, these residues can cause undesirable effects when the fabric is subsequently worn.
Therefore, it may be desirable to neutralise and/or to remove those residues prior to the subsequent use of the fabric.

It is already known that fabric conditioning compositions, many of which contain cationic materials, may be used in the post-wash rinsing or drying stage of a fabric laundering process, to soften fabrics and make them generally more comfortable to wear next to the skin.

It is also known to reduce the level of anionic residues to allow cationic material to soften fabrics more effectively.

For instance, GB 2039556 (Unilever) discloses a fabric conditioning composition comprising two or more cationic compounds which render the composition less sensitive to anionic carryover.

JP 7018571 (Lion Corporation) teaches an acid-neutralised amine compound which imparts flexibility to clothing in the presence of carried-over anionic surfactant.

US 4417995 (Lips et al) discloses reducing the effect of anionic carryover from the wash by incorporating into a fabric conditioning composition an inorganic polymeric material, which precipitates out anionic material.

EP 0323395 (Colgate-Palmolive) discloses that anionic residues on washed fabrics can be reduced using selected nonionic rinse formulations.

The present invention seeks to address the above-identified problems.

It has now been found that cationic materials, in particular cationic fabric conditioning materials, can reduce skin irritancy caused by anionic materials present on fabric after laundering.

The fact that this can be achieved, and the extent to which it occurs, had not previously been appreciated.

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Summary of the Invention The present invention provides the use of a cationic material to reduce skin irritancy of a material extractable from a fabric using water or an aqueous solution, wherein the cationic material is selected from:

(i) cationic surfactants;
(ii) cationic oligomers, polymers, co-polymers or mixtures thereof; or (iii) mixtures of (i) and (ii) and the material extractable from a fabric comprises one or more anionic surfactants and/or one or more soap residues.
According to a third embodiment, the invention provides the use of a cationic fabric conditioning composition to reduce skin irritancy of a material extractable from a fabric.

Detailed Description of the Invention In the context of the present invention, 'use' is defined as the application of the cationic material to, and/or its contact with, the fabric.
'Skin irritancy' is defined as the ability of a material to react chemically with (human) skin to cause a local inflammatory response following a single, repeated or continuous contact.
The irritant response may be characterised by symptoms such as erythema, oedema and/or skin dryness.

It is believed that the aforementioned skin irritancy can be reduced in a number of ways. For instance, the cationic material may neutralise free anionic residues on washed fabrics (such as by forming chemical complexes with them) and can prevent, or at least hinder, the subsequent release of the residues from the fabrics.

It is believed that neutralisation provides a complex which has no overall charge (at least during an intermediate stage of formation of the complex).

Thus, according to a first preferred aspect of the first embodiment, the invention provides the use of the cationic material to reduce skin irritancy of a material extractable from a fabric using water or an aqueous solution in which the cationic material neutralises free anionic residues on washed fabrics.

By 'free' residues is meant extractable residues, i.e., residues which can be extracted from a fabric by contact with water or an aqueous solution, for instance by contact with the wearer's sweat.

Without being bound by theory, it is believed that cationic materials can form chemical complexes with the free anionic residues. This can serve to reduce the extractability of the residues (the complexed residues being less likely to be soluble in water).

That is, it reduces the amount of 'free' residues on the fabric, preferably by forming chemical complexes with the free residues.

Thus, according to a second preferred aspect of the first embodiment, the invention provides the use of the cationic material to reduce skin irritancy of a material extractable from a fabric using water or an aqueous solution in which the cationic material forms chemical complexes with free anionic residues on a fabric.

It is believed that use of the cationic material may serve to reduce the extractability of the residues, i.e. prevent, or at least hinder, the subsequent release of the residues from the fabrics.

Thus, according to a third preferred aspect of the first embodiment, the invention provides the use of the cationic material to reduce skin irritancy of a material extractable from a fabric using water or an aqueous solution in which the cationic material prevents or at least hinders the subsequent release of free anionic residues from a fabric.
Without being bound by theory, it is believed that the mechanism for reducing irritancy, which preferably involves interaction (e.g. complexation) of the cationic material with the anionic residues, is different from the mechanism of softening, which involves depositing a softening compound onto the fabric in a way which provides a lubricating layer between fabric and skin.

Cationic Material The phrase 'cationic material' encompasses a single cationic material as well as a mixture of two or more cationic materials.

The cationic material is preferably a cationic surfactant, more preferably a cationic surfactant having fabric conditioning, such as fabric softening, properties.

Examples of suitable cationic surfactants for use in the present invention, either alone or in mixtures (such as with a polycationic material) are known in the art - see in particular Schwartz, Perry and Berch, 'Surface Active Agents' (Volumes I and II); Davidson and Milwidsky, 'Synthetic Detergents', John Wiley & Sons; and 'Household Industrial Fabric Conditioners' (Noyes Data Corporation).
They include, in particular, quaternary ammonium materials which comprise a polar head group and one or two alkyl or alkenyl chains.

Of these, materials having two long chain alkyl or alkenyl chains are particularly useful in the present invention. It is preferred that the average chain length is at least C14, and more preferred that each chain has an average chain length of or greater than C16. More preferably still, at least 50% of the long chain alkyl or alkenyl groups have a chain length of C18 or more.

It is preferred that the long chain alkyl or alkenyl groups be predominantly linear.

Well known quaternary ammonium compounds of use in the invention include those having the formula:

R 1 R 2 R 3 R 4 N + X'-wherein R1 and R2 represent hydrocarbyl groups having from 12 to 24 carbon atoms; R3 and R4 represent hydrocarbyl groups containing from 1 to 4 carbon atoms; and X is an anion, preferably a halide, methyl sulphate or ethyl sulphate anion.

Representative examples of quaternary ammonium materials having two long chain alkyl or alkenyl groups include di(tallow alkyl) dimethyl ammonium chloride; di(tallow alkyl) dimethyl ammonium methyl sulphate; dihexadecyl dimethyl ammonium chloride; di(hydrogenated tallow alkyl) dimethyl ammonium chloride (such as Arquad 2HT (trade mark)); di(hydrogenated tallow alkyl) dimethyl ammonium methyl sulphate; dioctadecyl dimethyl ammonium chloride;
dihexadecyl diethyl ammonium chloride; and di(coconut alkyl) dimethyl ammonium chloride.
The cationic surfactant could alternatively be a quaternary ammonium material of a single long chain type, preferably having the formula:

(R) 3N+R5 X

wherein each R group is independently selected from H or C1-C4 alkyl or hydroxyalkyl groups, R5 is a C8-C22 alkyl or alkenyl group, optionally interrupted by ester, amide, ether or amine functionality, and X is as defined above.
Preferred compounds of this type are linear C12-C18 alkyl or alkenyl trirnethyl ammonium chlorides and choline esters of C12-Clg fatty acids.

Other preferred cationic surfactants contain esters or amide links, for example, those available under the trade names Accosoft" 580, Varisoft' 2202 and StepantexT". The double long chain cationic materials of this type can be partially unsaturated (for instance tallow-derived materials like di(tallowoyloxyethyl) dimethyl ammonium chloride) or can contain long alkyl chains in the Clp-Clg range (e.g., di(cocoyloxyethyl) dimethyl ammonium chloride).

Particularly preferred cationic materials are quaternary ammonium materials having two C12-C18 alkyl or alkenyl groups connected to the molecule via at least one ester link. It is more preferred if the material contains two ester links.

A preferred ester-linked quaternary ammonium material for use in the present invention is represented by the general formula:

6-+-7-8 R N R T -R X

~
R-T - Re wherein each R6 group is independently selected from C1-C4 alkyl or hydroxyalkyl or C2-C4 alkenyl groups; each R7 group is independently selected from C1-C4 straight- or branched-chain alkylene groups; each R8 group is independently selected from C8-C28, preferably C12-C18, alkyl or alkenyl groups;

T is - C- 0- or - O- C-; and X is as defined above.
A particularly preferred material of this class is the fabric softener di-[2-(tallowoyloxy)ethyl] dimethyl ammonium chloride and its hardened tallow analogue (see DE-1,619,058).

Another preferred type of ester-containing quaternary ammonium material is represented by the formula:

(R6) 3 N+-(CH2) n- CH X

wherein R6, Ra and X are as defined above, and n is an integer from 0 to 5.

Preferred materials of this class, such as 1,2-bis-[tallowoyloxy]-3-trimethyl ammonium propane chloride or 1,2-bis-[hardened tallowoyloxy]-3-trimethyl ammonium propane chloride, are described for example in US-4,137,180, as is their method of preparation. Preferably these materials include small amounts of the corresponding monoester, as also described in US-4,137,180, for example 1-tallowoyloxy-2-hydroxy trimethylammonium propane chloride.

Preferred cationic fabric softening compounds are substantially water insoluble. 'Substantially water insoluble' surfactant compounds in the context of this invention are defined as compounds having a solubility less than 1 x 10-3 wt% in demineralised water at 20 C. Preferably the cationic surfactants have a solubility less than 1 x 10-4. Most preferably the cationic surfactants have a solubility at 20 C in demineralised water from 1 x 10-8 to 1 x 10-6wt%.

It is advantageous for environmental reasons if the cationic material used in the present invention is biologically degradable.

The cationic material may be a polycationic oligomer, polymer or co-polymer, which materials have been found to be particularly effective at neutralising free anionic residues. Such materials may be either synthetically or naturally derived.

Cationic monomers which are suitable for inclusion in 'addition' polymers or, co-polymers include diallyldimethylammonium chloride and quaternised 2-(N,N-dimethylamino)ethyl methacrylate. Other suitable cationic polymers include poly(ethylene imine) and derivatives thereof.

Such polycationic materials are preferably used together with one or more cationic surfactant(s), more preferably with one or more cationic fabric softening surfactant(s).
Fabric Treatment Compositions The cationic material can be included in a variety of fabric treatment compositions and products, of which the following are examples.

a. Rinse Conditioners The cationic material may be used in a cationic fabric conditioning composition (such as a rinse conditioning composition).

In the context of the present invention, a'cationic fabric conditioning composition' is defined as one which contains at least one cationic fabric conditioning material.

Preferably, the cationic material is used in the form of an aqueous dispersion, which may contain other materials with which the fabric is to be simultaneously treated.

The cationic fabric conditioning composition should be easily dispensable and easily dispersible in an aqueous rinse bath, and its viscosity is therefore preferably less than 300 mPa.s at 21 s-i, more preferably less than 200 mPa.s at 21 s 1. However, for reasons of product aesthetics and perceived product quality, the composition should preferably not have too low a viscosity - for instance no lower than 50 mPa.s at 21 s-l, more preferably no lower than 100 mPa.s at 21 s-1. (The viscosities quoted are measured at 20 C using a Haake RV20 rotoviscometer or similar equipment.) The cationic material can be used in a fabric laundering process, preferably a domestic laundering process, during which it is conveniently contacted with a laundered fabric during a post-wash rinse. The rinse may follow directly on from a machine or hand wash, or, it may be a separate fabric rinse which may even take place after the fabric has been both washed and dried.

Preferably all, or a substantial proportion (advantageously 85% or more by weight), of the composition's active fabric conditioning ingredients are cationic.

b. Direct Application Compositions The cationic material may be applied directly to a fabric at any time, for instance by spraying or dipping, to reduce skin irritancy of material extractable from the fabric. It may be applied to a newly manufactured or treated fabric as part of a fabric finishing treatment. It may also be applied, for instance in the form of an aerosol spray, during ironing of a fabric.

Accordingly, the cationic material can be used in a fabric treatment composition (such as a spray or a dip), in order to reduce skin irritancy of material extractable from a fabric. The composition may include other materials with which the fabric is to be treated.

c. Automatic Laundry Dryer Products The cationic material may be contained in an automatic laundry dryer product, such as a product for use in a tumble dryer. A suitable substrate, such as a porous sheet or a sponge, may be impregnated with or coated with the cationic material, in a manner which allows the release of the material from the substrate during its use in an automatic dryer. Tumble dryer sheets, for instance, may be made of any suitable flexible material such as paper or a woven or non-woven cloth. When such products are used in an automatic laundry dryer, the heat, moisture, distribution forces and tumbling action of the dryer remove the cationic material from the substrate and deposit it on fabric(s) being dried.

Such tumble dryer products can be designed for single or multiple use, a multiple use product comprising for instance a sponge substrate which releasably carries sufficient cationic material to impart the desired effect during several consecutive drying cycles. The cationic material may, for instance, melt and leach out of the sponge during drying, thereby coming into contact with the fabric(s) being dried.

Suitable substrate materials, for both single and multiple use products, and methods of impregnating or coating them, are discussed in US-5,254,269 (Lever).

The compositions and products in which the cationic material is included may also contain optional ingredients.

Optional Ingredients a. Nonionic Fabric Conditioners The fabric conditioning compositions may include other fabric conditioning materials such as nonionic fabric conditioners.

Preferred nonionic fabric conditioners include CPEs (cyclic polyols in which 4 or more of the hydroxyl groups are esterified and/or etherified and in which at least two or more of these ester or ether groups are independently of one another attached to a Cgto C22 alkyl or alkenyl chain) and RSEs (reduced saccharide in which 4 or more hydroxyl groups are esterified and/or etherified and in which at least two or more of these ester or ether groups are independently of one another attached to a C8 to C22 alkyl or alkenyl chain).
The C8 to C22 alkyl or alkenyl groups may be branched or linear carbon chains.
Examples of preferred cyclic polyols from which CPEs are derived include Inositol" and all forms of saccharides.
Examples of preferred saccharides are monosaccharides and disaccharides.

Examples of monosaccharides include xylose, arabinose, galactose, fructose, sorbose and glucose. Examples of disaccharides include maltose, lactose, cellobiose and sucrose.

An example of a reduced saccharide includes sorbitan.
Examples of suitable CPEs include sucrose octaoleate, esters of a1kyl(poly)glucosides, in particular alkyl glucoside esters having a degree of polymerisation from 1 to 2.

Examples of suitable saccharides esters include fatty acid esters of glucose, the ester groups comprising C2-C18 alkyl or alkenyl chain and the degree of esterification being 5 and in particular saccharides having ester groups consisting essentially of a C2 alkyl chain and a C8 to C12 straight alkyl chain, the molar ratio of short chain C2 alkyl chains to C8 to C12 straight alkyl chains being from 2:1 to 1:2, more preferably about 1:1.

b. Deposition Aids Materials which enhance deposition of the conditioning material(s) onto fabrics may also usefully be included in the composition. Such materials are often polymeric; GB-2,266,100 for instance discloses certain cellulose ethers for this purpose, and also mentions earlier documents which proposed materials able to bring about or enhance deposition.

c. Other Optional Ingredients For fabric conditioning compositions, typically aqueous compositions containing a dispersion of the relevant fabric conditioning material(s), other conventional ingredients which may be added include pH buffering agents, perfumes, perfume carriers, fluorescers, colourants, hydrotropes, antifoaming agents, antiredeposition agents, polyelectrolytes, enzymes, optical brightening agents, anti-shrinking agents, anti-wrinkle agents, anti-spotting agents, germicides, fungicides, anti-corrosion agents, drape imparting agents, anti-static agents, ironing aids, dyes, fatty acids and polymeric thickeners.

For tumble dryer sheets and the like, other conventional ingredients which may be carried on the substrate with the cationic material include other fabric conditioning materials, perfumes, perfume carriers, drape imparting agents, anti-static agents, ironing aids and deposition aids.
Fabrics Treated The fabric on which the cationic material or cationic fabric conditioning composition is used will typically be an item of clothing, in particular a garment intended to be worn next to the skin, such as an item of underwear or a t-shirt.
Anionic Residues The present invention may be used to reduce skin irritancy caused by many different types of anionic residues, especially detergents, which may be present on a fabric usually after washing. Anionic surfactant residues which may, for instance, be treated using the invention include sulphonates, in particular alkyl-aryl sulphonates such as alkyl benzene sulphonates, alkane sulphonates, olefin sulphonates, fatty acid ester sulphonates, sulpho-carboxylates, isethionates, sulphosuccinates and taurates;
sulphates, in particular primary and secondary alkyl sulphates, alkyl ether sulphates and alkyl phenol ether sulphates; carboxylates, in particular simple soaps such as sodium or potassium soaps, ethoxy carboxylates, phenol ethoxy carboxylates, sarcosinates, succinates and other multi-carboxylates; phosphates, in particular alkyl, alkane or alkyl ether phosphates; any combination of these materials; and any other surfactants used in fabric washing compositions.

Because it is the solubility of the residues in water which allows their extraction into, e.g., a wearer's sweat (from where there is the potential to cause skin irritation), the residues which are treated using the present invention are preferably those which are relatively water soluble, for instance having a solubility of at least 1% wt/wt in water at 20 C (which includes material existing in a micellar state in the solution).

Preferably, the amount of free anionic residues on a fabric is reduced by at least 50%, more preferably by at least 75%, by the use of the cationic material to treat the fabric.

The amount of cationic material used should preferably be at least, more preferably in excess of, the molar amount of free anionic residues on the fabric to which it is applied.
It is advantageous for the molar amount of cationic material applied to be over 5 times, preferably over 25 times, more preferably over 100 times, the amount of free anionic residues on the fabric.

The amount used will depend partly on the method of its application to the fabric. When the cationic material is used in a post-wash rinse, for instance, the amount present in the rinse liquor should be in molar excess of the total concentration of anionic surfactant in the liquor - indeed, it is preferred that the molar amount of cationic material be in this case at least 5 times greater, more preferably at S least 10 times greater, than the concentration of anionic surfactant in the rinse liquor.

Obviously, these dosage guidelines depend upon the amount of anionic material present in a given situation, both on the fabric being treated and in its surrounding environment.
However, for a typical European machine wash, it may be appropriate for the cationic material to be applied in the final rinse cycle at a concentration of 0.07 - 1.4 mmol/l, preferably 0.15 - 0.7 mmol/l.

The invention will now be further illustrated by means of the following non-limiting examples. Further modifications within the scope of the invention will be apparent to those skilled in the art.

Example 1 This demonstrates the effect of a cationic material upon the skin irritancy of a representative anionic surfactant, sodium dodecylsulphate (SDS).

0.3% SDS, and 0.3% SDS plus varying amounts of the cationic material, were patch-tested on the outer upper arms of 31 human panellists using the following standard procedure.

The cationic material used was di-[2-(hardened tallowoyloxy)ethyl] dimethyl ammonium chloride, added cold to the SDS as a pre-prepared liposomal dispersion in water.

Test materials were placed onto patches constructed of Finn Chambers on Fixomull" tape. The patched were applied for two 23-hour periods, separated by one hour. Assessment of the skin irritation response (erythema, oedema and dryness) was carried out by expert skin assessors 24, 48 and 72 hours after the first patch application.
The results are given in Table 1 Results - Table 1 Treatment mole % anionic Irritancy scorez complexed 0.3% SDS 0 26 + 0.18 wt % 25 16 cationic + 0.35 wt % 50 14 cationic + 0.53 wt o 75 7 cationic + 0.71 wt % 100 3 cationic 1 Number of panellists exhibiting an irritation response.
(NB. In all cases, the panellists demonstrated unequivocal responses.) These results indicate that the skin irritancy of anionic materials can be significantly reduced using a cationic material, in this case a cationic fabric softener.
Examples 2-4 and A

This demonstrates the ability of a cationic material to decrease damage to the human skin barrier caused by anionic residues.

Patch testing of fabric treated with an anionic surfactant and various amounts of a cationic softener was carried out on the upper arms of 8 male panellists.

Damage to the skin caused by anionic residues was measured using standard tape stripping and corneosurfammetry methods and involved standard dye penetration tests.

The assessment was based on the principle that an unbroken skin barrier prevents dye penetration whereas an irritant damaged barrier allows penetration of the dye. Thus, the less dye that was present in the skin, the less the skin barrier has been damaged by the anionic irritant.

Preparation of patches The fabric used in the following examples was prepared using 25cm by 50cm of cotton t-shirt material.

Comparative patches (hereinafter referred to as patch 'a') were prepared as follows. Cotton fabric squares were washed twice in a solution formed using a commercially available washing powder followed by washing ten times in boiling water to form a preharshened fabric. The fabric was then affixed to patches.

The washing powder used contained sodium linear alkylbenzene sulphonate (an anionic surfactant), together with nonionic surfactants, detergency builder, a bleach system, enzymes and perfume.

Test patches (hereinafter referred to as test patches 'b' to 'e') were prepared as follows. Cotton fabric squares were preharshened (as above), then washed in a solution formed using the commercially available washing powder (522g) and hard water (156 FH), and dried. The squares were then dipped into a tray containing various amounts of concentrated fabric conditioner in aqueous solution, gently agitated for 5 minutes, removed from the solution, line dried and then affixed to patches.

The fabric conditioner used contained a concentrated dispersion in water of the 'active' 1,2-bis-[hardened tallowoyloxy]-3-trimethyl ammonium propane chloride, which is a biodegradable cationic fabric softening surfactant.

The amounts of fabric conditioner used are shown in table 2.
Table 2 Test patch Test patch 'c' Test patch 'd' Test patch 'b' 'e' No fabric 2g fabric 4g fabric 8g fabric conditioner conditioner conditioner conditioner Each panellist had a preharshened control patch 'a' applied to one arm and a test patch selected from patches 'b', 'c', 'd' or 'e' applied to the other arm, as shown in table 3.
Examples of the invention are denoted by a number and comparative examples are denoted by a letter.

Table 3 Example A 2 3 4 Patch 'a' + Patch 'a' + Patch 'a' + Patch 'a' +
patch 'b' patch 'c' patch 'd' patch 'e' After 24 hours, the patches were removed and an adhesive tape was used to take a top layer of the skin barrier which had been in contact with the patch.

2 panellists were used per example. Each panellist had 3 patches on each arm. For each patch, 2 tape strips were taken and 3 readings were made for each tape strip. Thus, for each example, the result was calculated using the average result over 36 readings.

Assessment of the patches Assessment was carried out using standard csm techniques in which the amount of dye penetrating through irritant damaged skin was measured using a spectrophotometer and the result expressed as the Colorimetric Index of Mildness - CIM (see 'Corneosurfammetry - A predictive assessment of the interaction of personal care cleansing products with human stratum corneum', G.E.Pierard, V.Goffin, C.Pierre-Franchimont, Clin.Lab.Invest., 1994, 189, 152-156.).

The results are given in table 4 Results - Table 4 Example 1 CIM Difference A 1.17 2 -1.55 3 -3.11 4 -6.53 1'CIM Difference' equals the CIM reading for patch 'a' minus the CIM reading for patches 'b' to 'e'. The lower the value of 'CIM Difference', the less the dye has penetrated the skin (indicating less irritant damage to the skin).

The results showed that the greater the amount of fabric conditioner present in the test patch, the less the dye penetrated the skin sample. Therefore, the use of the cationic softening compound clearly reduced the level of irritant damage to the skin caused by the anionic residues.
Example 5 This demonstrates a reduction in free (i.e., extractable) anionic detergent residues on laundered fabrics, using a cationic fabric conditioning composition.

Two identical 2.5 kg loads (A and B) of mixed fabric were laundered in Miele washing machines using 100 g of a commercially available non-biological washing powder. Load A was not treated with any fabric conditioner post-wash;
load B was treated with fabric conditioner in the final rinse cycle, at a level of 3 g of 'active' conditioning material per kg of fabric.

The washing powder used contained sodium linear alkylbenzene sulphonate (an anionic surfactant), together with nonionic surfactants, detergency builder, a bleach system and perfume.

The fabric conditioner used was a concentrated dispersion in water of the 'active' 1,2-bis-[hardened tallowoyloxy]-3-trimethyl ammonium propane chloride, which is a biodegradable cationic fabric softening surfactant.

Following Iaundering, 100 square centimetres of fabric were removed from each washing machine and each soaked in 50 ml of demineralised water for 24 hours. The extracts obtained from these soakings were filtered and their free anionic surfactant contents determined by complexiometric titration of 10 ml aliquots with 0.0005 M hyamine solution. HyamineTM
is able to complex with the anionic surfactants present in the washing powder used.

The results are given in Table 5 Results - Table 5 Load Titrant required o reduction in (m1) free anionic A 0.84 0 B 0.11 87

Claims (16)

1. The use of a cationic material to reduce the skin irritancy of a material extractable from a fabric using water or an aqueous solution, wherein the cationic material is selected from:

(i) cationic surfactants;
(ii) cationic oligomers, polymers, co-polymers or mixtures thereof; or (iii) mixtures of (i) and (ii) and the material extractable from a fabric comprises one or more anionic surfactants and/or one or more soap residues.

2. The use according to claim 1 in which the cationic material is selected to neutralise free anionic residues present on the fabric.

3. The use according to claim 1 in which the cationic material is selected to form chemical complexes with free anionic residues on the fabric.

4. The use according to claim 1 in which the cationic material is selected to at least partially prevent the subsequent release of free anionic residues from the fabric.

5. The use according to any one of claims 1 to 4, wherein the cationic material is a cationic surfactant.

6. The use according to claim 5, wherein the cationic surfactant is a quaternary ammonium material having either by formula(1):

wherein each R6 group is independently selected from C1-C4 alkyl or hydroxyalkyl or C2-C4 alkenyl groups; each R7 group is independently selected from C1-C4 straight-or branched-chain alkylene groups; each R8 group is independently selected from C8-C28, alkyl or alkenyl groups;

and X- is a compatible counterion;
or formula (2):

wherein R6, R8 and X- are as defined above and n is an integer from 0 to 5.

7. The use according to any one of claims 1 to 4, wherein the cationic material is selected from the group consisting of a polycationic oligomer, polymer or co-polymer, an addition polymer or co-polymer of diallyl ammonium chloride, quaternised 2-(N,N-dimethylamino)ethyl methacrylate and mixtures thereof.

8. The use according to claim 7, wherein the cationic material is selected from the group consisting of poly(ethylene imine), a derivative thereof and mixtures thereof.

9. The use according to claim 7 or 8, wherein the polycationic material is used together with one or more cationic fabric softening surfactant(s).

10. The use according to any one of claims 1 to 9, in which the cationic material is contained in a fabric treatment composition or product.

11. The use according to any one of claims 1 to 10, wherein the cationic material is contacted with a laundered fabric during a post-wash rinse in a fabric laundering process.

12. The use according to any one of claims 1 to 10, wherein the cationic material is applied directly to the fabric in the form of a spray or dip.

13. The use according to any one of claims 1 to 10, wherein the cationic material is used in an automatic laundry dryer product.

14. The use according to any one of claims 2 to 4 or claims to 13 when dependent thereon, wherein the cationic material is selected to reduce the amount of free anionic residues on the fabric by at least 75%.

15. The use of the cationic material as defined in claim 1, or a cationic fabric conditioning composition containing said material in a post-wash rinse or drying process in order to reduce skin irritancy of a material extractable from a fabric using water or an aqueous solution, wherein the material extractable from a fabric is as defined in claim 1.

16. The use of a cationic fabric conditioning composition to reduce skin irritancy of a material extractable from a fabric using water or an aqueous solution, wherein the composition contains the cationic material defined in claim 1, and wherein the material extractable from a fabric is as defined in claim 1.