GB2507752A - Fabric softener compositions - Google Patents

Abstract

A fabric softener comprises an active ingredient which provides the fabric with skin moisturising properties. The fabric softener composition comprising a carrier or bulking agent, at least one surfactant, and a polymer containing at least one phospholipid active group. The phospholipid active group may be a methacrylate based phospholipid-analagous polymer or copolymer. The surfactant may be a quaternary ammonium salt. Also shown is a substrate impregnated with the fabric softener and a fabric treated with the fabric softener.

Description

Fabric softener This invention relates to a fabric softener comprising an active ingredient which provides the fabric with skin moisturising properties.

It has become common in the consumer and residential sector to use fabric softening compositions that include surfactants and low quantities of optional ingredients such as perfumes, stabilisers, preservatives and colorants. The softeners are usually conveniently added to a washing machine in liquid form.

Fabric softeners contain surfactants which have lubricant properties and are electrically conductive. The surfactants prevent static electricity and make the fabrics fe& smoother. Tn addition, the softener compositions can often provide a thin coating on the fabric fibres to make the fabric fluffier, softer and better smelling.

There are two main types of fabric softener; those that use cationic surfactants and those that use anionic surfactants. The choice of softener can vary depending on the fabric to be treated. Some softeners are more suitable for cellulose-based fibres, whilst others have a higher affinity to hydrophobic materials such as nylon, polyethylene terephthalate, polyacrylonitrile, etc. Softener compositions are usuafly prepared as an emulsion, as the surfactants are frequently hydrophobic.

The lubricating properties of the cationic softeners are due to the positive charges of the surfactants within the softener composition. Surfactants are usually acidic and the positively charged particles of the surfactant attract the negatively charged partides within the fabric. The negative charge of the fabric is neutralized, creating a lower frictional resistance. This reduces the static cling and the fabric feels softer to touch. The molecules of these surfactants tend to have long aliphatic chains which are oriented towards the outside of the fibre, providing lubrication. As cationic surfactants can impact the water adsorption properties of the fabric, they are often combined with other chemicals which have a lower affinity to the fibres.

Many commercial fabric softeners are based on quatemary ammoniurn salts with one or two long alkyl chains, for example, dipalniitoylethy hydroxyethylmonium methosulfate. Other cationic compounds can be derived from imidazolium, substituted aniine salts, or quaternary alkoxy ammonium salts. Early formulations commonly used dihydrogenated tallow dimethyl ammonium chloride (DHTDMAC).

Fabric softeners containing quaternary ammonium salts operate well in conventional residential wash and dryer cycles and provide softness to textiles that are both woven and non-woven.

Cationic surfactants are incompatible with the anionic surfactants used in detergents, with which they tend to foni a solid precipitate. Therefore, they have to be added during a separate cycle, typically the rinse cycle of a conventional domestic washing machine. In contrast, anionic softeners can be directly combined with anionic surfactants. Examples of anionic surfactants and antistatic agents are salts of monoesters and diesters of phosphoric acid and the fatty alcohols. They can also be combined with more convention& cationic softeners. This has led to the development of two-in-one formulations, where the fabric softener is combined with the detergent.

A further development is the ability to add a fabric conditioner to fabrics in a tumble dryer. Fabric softener is applied to a flexible substrate that carries the fabric softener and is added to the drying cycle. The advantages of this method of conditioning the fabric include avoiding a separate wash cycle for the addition of a fabric sofiener, and avoiding any undesired interactions of the soflening agents with detergents.

The present invention relates to a fabric conditioner that imparts skin moisturising properties on the fabric. According to the present invention, there is provided a fabric softener comprising a carrier or bulking agent, at least one surfactant, and a polymer containing at least one phospholipid active group. The surfactant can be a quaternary ammom urn salt, for exarnple. The fabric softener may take the form of a liquid formulation, or alternatively the liquid formulation may be applied to a suitable substrate for use in a tumble-dryer. It is also possible to formulate the fabric softener composition as a dry powder, for dispersion in a liquid during a conventional waslVrmse cycle.

One example of a suitable composition for tile fabric softener of the present invention comprises a quatemary ammoniurn salt; a carrier; and a further active ingredient to provide skin moisturising properties, in the form of a polymer containing at least one phospholipid active group, such as a phospholipid-analogous polymer or copolymer.

The formulation may further comprise one or all of the following; viscosity modifiers, preservatives andlor perfume.

The fabric softener contains an active ingredient which is similar iii structure to the polar group of phospholipids in the human ecU membrane. The active ingredient can be a phospholipid allalogous polymer or copolyrner (i.e. a natural or sylillietic phospholipid). One example of a suitable copolymer is a methacrylate-based copolymer. The nature of these polymers is both hydrophobic and hydrophilic. The hydrophilic element provides a moisture retaining and enhancing property. The hydrophobic element effectively disp'aces other m&ecules from either attaching to the fabric or from dispersing through fabric during use and therefore provides an external barrier effect agaillst imtallts. Copolymers with a phospholipid polar group tend to be highly water soluble due to the length of the hydrocarbon chain iii the structure of the molecules.

Particularly preferred forms of the invention include fabric softeners intended for use during the wash cycle or final rinse of a wash cyde in the form of liquids or powders.

The terms "fabric conditioner" and "fabric softener" should be understood to be interchangeable in the context of this application. The fabric softener can also be applied to a substrate for use in a dryer, where the fabric softening properties of the formulation are imparted to the fabric articles during a drying step. The dryer may be a tumble-type dryer or equivalent. The fabric softener can be used in either residential machines, or in industrial and institutional settings. This includes fabric or textile laundering operations in commercial or service industries, including for example, hotels, hospitals, nursing homes, restaurants, health clubs, prisons, etc., as well as the preparation of fabrics in a factory setting.

As mentioned above, one component of the fabric softener composition is a quaternary ammonium compoirnd. Examples of suitable quaternary ammonium compounds that could be used include ailcylated quaternary ammonium compounds, al koxylated quaternary amnioni urn compounds, ring or cyclic quaternary ammoniuni compounds, aroniati c quaternary ammoni um compounds, di-quaternary amnioniuni compounds, amidoamine quaternary ammonium compounds, ester quaternary ammonium compounds and triethanolarnine based esterquats. A mixture of one or more of these compounds could also be used.

Many quateniary ammonium compounds, particularly those with ester linkages in the aliphatic chains, have demonstrated improved biodegradation kinetics, lowering the environmental bioaccumulation levels.

The quateniary ammonium compounds may use any counter ion that has fabric softening properties. Examples of suitable counter ions include chloride, methyl sulphate, ethyl sulphate and sulphate. Particularly preferred surfactants include di-hydrogenated tallow hydroxyethylrnoniuni methosulphate, dirnethyl distearic amnionium chloride, bisQydrogenated tallow alkyl) dimethylanimonium chloride, and dipalmitoylethyl hydroxyethylrnoniurn methosulphate.

The amount of quaternary ammonium component can be in the range of approximately 2% to 30°A by weight of the final product. More preferably, the quaternary ammonium content can be from approximately 5% to 20% by weight, from approximately 10% to 15% by weight or most preferably, from 11 to 13% by weight of the final product.

Where the fabric softener is a liquid, the carrier for the formulation is preferably water. This may be tap water, but is more preferably de-ionised water. Optionally distilled, purified or filtered water can be used. The carrier can be formed from a mixture of water and water soluble organic solvents, such as short-chain alcohols.

Ethanol, propanol, isopropanol, butanol, benzyl alcohol and mixtures of these solvents can be added to the water in quantities of up to approximately 10% by weight, more preferably up to approximately 5% by weight, of the carrier fluid.

Soluble organic solvents such as the alcohols mentioned above are used if it is desirable to increase the concentration of active ingredients in the fabric softener composition whilst still retaining the desired product viscosity.

If a free flowing powder form of the fabric conditioner is required, it may be necessary to use atoniised powders of the desired quaternary animonium compounds.

USS,200,097 (Hughes et al) describes the advantages of adding processing aids such as polyoxyallcylene derivatives to quaternary ammonium compounds prior to atonhisation. Any suitable bulking agent or can-icr can be used in combination with the atornised quaternary ammonium compounds.

The fabric conditioner may also be provided on a substrate impregnated with the fabric softening ingredients, for use in a drying cyde. The substrate can be a sponge, cloth (woven/knitted or non-woven), a porous sheet, paper or any other suitaHe vehicle for carrying the fabric softener. Preferably, the substrate will have an open or porous structure, and good absorbent properties. The amount of conditioning composition affixed to the flexible substrate may vary depending on the size of the substrate and the degree of fabric conditioning desired. The fabric conditioner is preferably applied in liquid form to the substrate, and this is commonly achieved by processes such as dipping or spraying. Following the application of the liquid fabric softener, the substrates are dried to evaporate any residuai solvents (e.g. water).

For liquid formulations, viscosity modifiers or control agents can be used to reduce the viscosity of the formulation, in order to produce a pourable formulation with a viscosity that is acceptable to the consumer. Examples of viscosity modifiers include fatty acids and esters, water-miscible solvents and water-soluble ionisable salts.

Water-soluble calcium salts are particularly suitable for use as viscosity modifiers.

Cathiurn chloride is one preferred example of a calcium salt suitable for use as a viscosity modifier, although alternatives such as magnesium chloride, sodium chloride, potassium bromide and lithium chloride can also be used. Jonisable salts also have the added advantage that they can often improve the performance of the surfactant. Relatively low concentrations tend to be required. Viscosity agents can be present in liquid formulations in quantities of between O.OOlwt% and lwt%, more preferably between O.Olwt% and O.Swt%, and most preferably in the range of O.Olwt% and O.lwt%.

The active ingredient, a phospholipid analogous polymer or cop&ymer, is present iii liquid fornmlations in concentrations of between 0. lwt% and 2Owt%, more preferably between 0.Swt°A and lOwt% and most preferably between lwt°A and 6wt%. The phospholipid analogous polymer may be a methacrylate-based copolynier, for example, a copolyrner comprising 2-methacryloyloxyethyl phosphorylcholine (MPC). For example the active ingredient may be methacryloyloxyethyl-2 -(trimethylammonuimethyl)-phosphate, inner salt- stearylmethacrylate; or poly(2-methacryloyloxyethyl phosphorylcholine-co-2-ethylhexylmethacrylate-co-N,N-diethyl aminoethyl methacrylate).

The formulation may also include preservatives, anti-static agents, odour capturing agents and perfumes. Perfumes may be formed from natural or synthetic ingredients.

Stabilisers or preservatives are used to improve the shelf-life of fabric softeners. For fabric softeners in liquid form, the stabilisers ensure the stability of the emulsion during storage, even at variable temperatures. Stabilising agents may include antioxidants, such as ascorbic acid, propyl gallate and citric acid and reductive agents, such as sodium borohydride and hypophophorous acid. Preservatives can include anti-microbial agents such as isothiazolinone-based chemicals (in particular isothiazol-3-one biocides) or glutaraldehyde-based products. As a guide, preservatives can be present in a liquid formulation in quantities of up to about 0.3%, more preferably less than 0.2%. The fabric softener composition may contain a mix of two or more stabilising agents and/or preservatives.

Whether a fabric is soft is a quality peTceived by users through their tactile senses.

Such tactile perceivable softness may be characterised by, but not limited to resilience, flexibility, fluffiness, slipperiness, pliability and smoothness, as well as

subjective descriptions such "feeling like sillc".

The active copolyrner ingredient in the fabric softener acts to release moisture onto the skin when the fabric is worn or used. The moisturising coating of phospholipid-analogous copolyrner on the fabric can be easily and routinely applied or replenished by the consumer during a norm& laundering process. The moisturising coating that is achieved on the fabric is relatively uniform due to the method of application of fabric softeners. The fabric softener is either dispersed in a fluid and impregnated onto the fabric during a conventional rinse cycle, or released from a substrate and impregnated onto the fabric during a turnble-diying step.

It will be recognised by a person skilled in the art that numerous formulations can be produced according to the invention. Non-limiting examples of suitable formulations are provided below.

Example 1

A first example of a liquid fabric softener composition: Chemical Name %wt in final product Function Water To 100% Carrier (solvent) di-hydrogenated tallow 10 -5 Cationic surfactant hydroxycthylmonium mcthosulphate (Esterquat) Calcium chloride 0.001 -0.2 Viscosity modifier 5-chloro-methyl-2H-isothiazol-3-one 0.03 -0.1 Preservative 2-methyl-2H-isothiazol-3-one 0.001 -0.002 Preservative Fragrance 0.4 -1.2 Perfume Methaciyloyloxyethyl-2'-0.5 -6 Moisturising agent (trinethy1ainnioniumethyl)phosphate, inner salt-stearylmethaciylate copoloymcr

Example 2

A second, fragrance-free, example of a liquid fabric softener composition: Chemical Name %wt in final product Function Water To 100% Carrier (solvent) bis(hydrogcnatcd tallow alkyl) 10 -15 Cationic surfactant dimethylammonium chloride Calcium chloride 0.00 1 -0.3 Viscosity modifier 5-chloro-2-methyl-4-isothiazolin-3-0.001 -0.15 Preservative one Fragrance 0 Perfume Methacryloyloxyethyl-2'-1 -10 Moisturising agent (trimetbylammoni umethyl)phosphate, inner salt-stearylmethacrylatc copoloymer

Claims (18)

1. Claims 1) A fabric softener composition comprising a carrier or builcing agent, at least one surfactant, and a polymer containing at least one phospholipid active group.
2. 2) The fabric softener according to Claim 1, where the polymer containing at least one phospholipid active group is a phospholipid-analogous polymer or copolymer.
3. 3) The fabric softener composition according to Claim 2, where the phospholipid-analogous polymer or copolymer is methacrylate based.
4. 4) The fabric softener composition according to any preceding claim, wherein the polymer containing at least one phospholipid active group is a 2-methacryloyloxyethyl phosphorylcholine (MPC) based polymer.
5. 5) The fabric softener composition according to Claim 4, where the polymer containing at least one phospholipid active group is a methacryloyloxyethyl- 2' -trimethylanimoniuniethyl)pho sphate, timer salt-stearyliriethacrylate copolymer.
6. 6) The fabric softener composition according to any preceding claim, comprising between from O.lwt% to lOwt% of a polymer containing at least one phospholipid active group.
7. 7) The fabric softener composition according to any preceding dairn, where the at least one surfactant is a quaternary ammonium salt.
8. 8) The fabric softener composition according to Claim 7, comprising between 2wt% and 4Owt% of a quaternary ammonium salt.
9. 9) The fabric softener composition according to any preceding claim, further comprising at least one viscosity modifier.
10. 10) The fabric softener composition according to Claim 9, where the viscosity modifier is calcium chloride.
11. 11) The fabric softener composition according to any preceding claim, further comprising at least one preservative.
12. 12) The fabric softener composition according to any preceding claim, further comprising at least one perfume.
13. 13) The fabric softener composition according to any preceding claim, where the carrier is a Uquid so'vent.
14. 14) The fabric softener composition according to Claim 13, where the carrier comprises water or is a mixture of water and an alcohol.
15. 15) A substrate impregnated with the fabric softener composition of any preceding claim.
16. 16) The fabric softener composition according to any one of Claims 1-12, where the carrier is bulking agent in diy powder form, further comprising at least one processing aid.
17. 17) The fabric softener composition according to Claim 16 where at least one processing aid is a polyoxyalkylene compound.
18. 18) A fabric which has been treated by tile fabric softener composition according to any preceding claim.