GB2513361A

GB2513361A - Fabric softener

Info

Publication number: GB2513361A
Application number: GB1307410.9A
Authority: GB
Inventors: George Costa; Tony Wilson
Original assignee: Intelligent Fabric Technologies PLC
Current assignee: Intelligent Fabric Technologies PLC
Priority date: 2013-04-24
Filing date: 2013-04-24
Publication date: 2014-10-29
Also published as: WO2014174272A1; EP2989191A1; GB201307410D0

Abstract

A fabric softener composition comprises a carrier or bulking agent, at least one surfactant, and at least one biocidal agent. The at least one biocidal agent may be a biguanide compound, such as polyhexamethylene biguanide (PHMB) hydrochloride, a polyhexidine compound, or benzalkonium chloride. Preferably, more than one biodical agent is used. The at least one surfactant may be a quaternary ammonium salt, such as a di-hydrogenated tallow hydroxyethylmonium methosulphate.

Description

Fabric Softener This invention relates to a fabric softener comprising an active ingredient which provides the fabric with biocidal 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 feel smoother. In 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, p0] yacrylonitrile, etc. Softener compositions are usually prepared as an emulsion, as the surfactants are frequenfly 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 particles 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 quaternary ammonium salts with one or two long alkyl chains, for exarnpe, dipahnitoylethyl hydroxyethylnioniuni methosulfate. Other cationic compounds can be derived from i midazoliurn, substituted amine 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 form 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 conventional cationic softeners. This has ed 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 indude avoiding a separate wash cycle for the addition of a fabric softener, and avoiding any undesired interactions of the softening agents with detergents.

The present invention relates to a fabric conditioner that imparts antibacterial properties to the fabric. According to the present invention, there is provided a fabric softener comprising a carrier or builcing agent, at least one surfactant, and at least one biocida] ingredient. The surfactant can be a quaternary ammonium salt, for example. The fabric softener may take tile form of a Uquid 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 wash/rinse cycle.

One example of a suitable composition for the fabric softener of the present invention comprises a quaternary ammonium salt (the surfactant); a carrier: and an active ingredient which provides biocidal properties. The biocide may be an antimicrobial or antibacterial agent, for example. More than one biocidal agent may be combined. The biocide is preferably an effective fungicide. The formulation may further comprise one or all of the following; viscosity modifiers, preservatives and/or perfume.

The fabric softener contains at least one active ingredient which lends biocidal properties to the softener. The biocide is used to kill or inhibit the growth of microorganisms such as bacteria, fungi, and protozoans. The biocidal properties imparted by the fabric softener prevent the growth of mildew or bacteria on the fabric. As these are common causes of malodour, the biocide helps to keep the fabric smelling freshly washed. This effect lasts longer than it would if an ordinary fabric softener, without additional biocidal ingredients, were to be used.

It also has a stronger and longer lasting effect than that provided by any preservatives included in an ordinary fabric softener composition. The primary aim of the preservatives used iii ordinary fabric conditioners is to improve the shelf-life of the product, rather than to prevent bacterial, protozoan or furigal growth on the treated fabric. Combinations of biocidal ingredients can be used to deliver targeted action against different types of organisms.

Particularly preferred forms of the invention include fabric softeners intended for use during the wash cycle or final rinse of a wash cycle in the form of liquids or powders. The terms "fabric conditioner" arid "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 compound, acting as a surfactant to provide the lubricating properties expected from a fabric softener. Examples of suitable quaternary amnioniuni compounds that could be used include alkylated quaternary ammonium compounds. alkoxylated quaternary ammonium compounds, ring or cyclic quaternary ammonium compomids, aromatic quaternary ammonium compounds, di-quaternary ammonium compounds, amidoamine q uaternary ammonium compounds, ester quaternary ammoni um compounds and triethanolamine based esterquats. A mixture of one or more of these conipounds could &so be used.

Many quaternary ammonium compounds, particularly those with ester linkages iii the al iphatic chains, have demonstrated improved biodegradation kinetics, lowering the environmental bioaccumulation levels.

The quaternary 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 inc'ude di-hydrogeriated tallow hydroxyethyl nioriium niethosulphate, dimethyl disteari c ammoniurn chloride, bisydrogenated tallow ailcyl) dimethylammonium chloride, and dipalmitoylethyl hydroxyethylmonium methosulphate.

The amount of quaternary ammonium component can be in the range of approximately 2% to 30% 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.

A/here 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 nñxtures 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 atomised powders of the desired quaternary ammoniurn compounds. US5,200,097 (Hughes et al) describes the advantages of adding processing aids such as polyoxyallcylene derivatives to quaternary ammonium compounds prior to atonñsation. Any suitable hulking agent or carrier can be used in combination with the atomised quaternary ammonium compounds.

The fabric conditioner may also be provided on a substrate impregnated with the fabric softening ingredients, for use in a drying cycle. The substrate can be a sponge, cloth (woven/knitted or non-woven), a porous sheet, paper or any other suitable 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 residual 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 acceptaHe 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. Calcium chloride is one preferred example of a calcium salt suitable for use as a viscosity modifier, although ahernatives such as magnesium chloride, sodium chloride, potassium bromide and lithium chloride can also be used. lonisable 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 0.OOlwt% and lwt%, more preferably between 0.Olwt% and 0.5wt%, and most preferably in the range of 0.Olwt% and 0.lwt%.

The formLilation 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 hypophosphorous 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 andlor preservatives. As the active ingredient of the formulation is a biocidal agent, the use of an addition& preservative becomes optional.

The active ingredient, the biocidal agent, is present in liquid fornrnlations in concentrations of between 0.00 lwt% and lOwt%, more preferably between 0. lwt% and 7wt% and most preferably between 0.5wt% and Swt%. The biocidal agent may be present in addition to or in the place of any preservatives that are ordinarily used. More than one biocidal agent may be used in combination to target different organisms. The biocidal agent may be a pesticide, for example, a fungicide, herbicide, insecticide, algicide; an antimicrobial agent, for example, a germicide, antibiotic, antibacterial, antiparasitic, antiviral; an antiprotozoal agent; or a combination of one or more of these. The biocidal agent is used to prevent growth of organisms (such as bacteria or firngi) on the surface of the fabric for a prolonged period of time after the fabric has been washed, thus keeping the fabric smelling and feeling fresher for a longer.

Many biocidal agents target a wide range of microorganisms. Examples of suitable biocides for use in a fabric conditioner include glycol ethers, quaternary ammoniurn chlorides, polyhexinides, biguanides and amidines.

Examples of suitable compounds for use as the active ingredient in the fabric softener, the biocidal agent, include: polyhexamethylene guanide (P11MG), polyhexaniethylene biguanide (P11MB), polyhexamethylene biguanide hydrochloride, poly(hexamethylenebiguanide) hydrochloride, or benzalkonium chloride (also known as alkyldimethylbenzylammonium chloride, or ADBAC), phcnoxycthanol, or a combination of two or more of these compounds. For example, the active ingredient could comprise a combination of benzalkonium chloride and polyhexamethylene biguanide. When two biocidal agents are used, the relative concentrations of the two may range between about 1:25 and 10:1.

For example, the concentration of the first biocida agent may be in the range 0.00 -to 0.2wt% and the second biocidal agent may have a concentration in the range 0.02 -5.5wt%. Further, the concentration of the first biocidal agent may be in the range of 0.01 -0.O3wt%, and the concentration of the second biocidal agent may be in the range of 1 -3wt%. For example, the concentration of the first biocidal agent may be approximately 0.024wt% and the concentration of the second biocidal agent may be approximat&y I.25wt%, 2.45wt%, or 2.48wt%.

Benzalkonium chloride solutions have a moderately long duration of action and are active against bacteria, some viruses, fungi and protozoa. Benza]koniurn chloride is suitable for use with quaternary ammonium formulations and other cationic surfactants. Polyhexamethyleiie biguanide (P1-1MB) is capable of killing bacteria and viruses and is capable of controlling algae and other microorganisms. It is often used in antimicrobial hand washes. Biocidal activity is not affected by the hardness of the water, or by water temperature.

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 -15 Cationic surfactant hydroxycthylmonium mcthosulphate (Esterquat) Calcium chloride 0.001 -0.2 Viscosity modifier 5-chloro-methyl-2H-isothiazol-3-one 0.02 -0.08 Preservative 2-methyl-2H-isothiazol-3 -one 0.001 -0.01 Preservative Fragrance 0.4 -1.2 Pcrffime Alkyldimcthylbcnzylarnmonium 0.2 -10 Biocidal agent chloride

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(hydrogcnated tallow alkyl) 10 -15 Cationie surfactant dimethylammonium chloride Calcium chloride 0.001 -0.3 Viscosity modifier 5-chloro-2-methyl-4-isothiazolin-3-0.001 -0.15 Preservative one Fragrance 0 Perfume Poly(hexamcthylenebiguanide) 0.5 -S Biocidal agent hydrochloride

Example 3

A third example of a liquid fabric softener composition: Chemical Name %wt in final product Function Water To 100% Carrier (solvent) di-hydrogenated tallow 10 -20 Cationic surfactant hydroxyethylmonium mcthosulphate (Esterquat) Calcium chloride 0.001 -0.2 Viscosity modifier 5-chloro-methyl-2H-isothiazol-3-one 0.02 -0.1 Preservative 2-methyl-2H-isothiazol-3 -one 0.001 -0.01 Preservative Fragrance 0.4 -1.2 Perfume Benzalkonium chloride 0.5 -7 Biocidal agent

Example 4

A fourth example of a liquid fabric softener composition: Chemical Name %wt in final product Function Water To 100% Carrier (solvent) di-hydrogcnatcd tallow 10 -15 Cationic surfactant hydroxyethylmonium methosulphate (Esterquat) Calcium chloride 0.001 -0.2 Viscosity modifier 5-chloro-methyl-2H-isothiazol-3-orie 0.02 -0.08 Preservative 2-methyl-2H-isothiazol-3 -one 0.001 -0.01 Preservative Fragrance 0.4 -1.2 Perfume Poly(hexamethylenebiguanide) 0.001 -0.2 Biocidal agent hydrochloride Benzalkonium chloride 0.5 -5.5 Biocidal agent

Example S

A fifth example of a liquid fabric softener composition: Chemical Name %wt in final product Function Water To 100% Carrier (solvent) di-hydrogenated tallow 10-15 Cationic surfactant hydroxycthylmonium mcthosulphate (Esterquat) Calcium chloride 0.00 1 -0.2 Viscosity modifier 5-chloro-methyl-2H-isothiazol-3-one 0.02 -0.08 Preservative 2-methyl-2H-isothiazol-3 -one 0.001 -0.01 Preservative Fragrance 0.4 -1.2 Pcrfumc Poly(hexamethylenebiguanide) 0.01 -0.03 Biocidal agent hydrochloride Benzalkonium chloride 1 -3 Biocidal agent

Claims

Claims 1. A fabric softener composition comprising a carrier or bulking agent, at least one surfactant, and at least one biocidal agent.
2. A fabric softener composition according to Claim 1, where at least one biocidal agent is a biguanide compound.
3. A fabric softener composition according to Claim 2, where the biguanide compound is polyhexamethylene biguanide (PHMB).
4. A fabric softener composition according to Claim 2, where the biguanide compound is pol yhexamethylene biguaiii de hydrochloride.
5. A fabric softener composition according to Claim I, where at east one biocidal agent is a polyhexinide compound.
6. A fabric softener composition according to Claim 1, where at least one biocidal agent is benzalkonium chloride.
7. A fabric softener composition according to any preceding claim, where more than one biocidal agent is used.
8. A fabric softener composition according to any preceding claim, where a first biocidal agent is polyhexamethylene biguanide and a second biocidal agent is benzalkonium chloride.
9. A fabric softener composition according to any preceding claim, where the total concentration of the biocidal agent is at least O.Swt%.
10. A fabric softener composition according to any preceding claim, where the tot& concentration of the biocidal agent is in the range of O.Swt?/o to lOwt%.
11. A fabric softener composition according to any preceding claim, where the total concentration of the biocidal agent is in the range of 0.Swt?/o to 7wt%.
12. A fabric softener composition according to any preceding claim, where the total concentration of the biocidal agent is in the range of 2wt% to Swt%.
13. A fabric softener according to any preceding claim, where the at least one surfactant is a quaternary ammonium salt.
14. A fabric softener according to Claim 12, where the quaternary ammonium salt is di-hydrogenated tallow hydroxyethylnioniurn niethosulphate.
15. A fabric softener according to Claim 12, where the quaternary ammonium salt is dimetliyl distearic ammonium chloride.
16. A fabric softener according to Claiml2, where the quaternary ammoniums salt is bis(hydrogcnatcd tallow alkyl) dimcthylammonium chloride.
17. A fabric softener according to any preceding claim, where the concentration of the surfactant is in the range of Swt% to 3Owt%.
18. The fabric softener composition according to any preceding claim, further comprising a perfume.
19. Thc fabric softcncr composition according to any preceding claim, further compnsmg a preservative.
20. The fabric softener composition according to any preceding claim, where the carrier is a liquid solvent.
21. The fabric softener composition according to any preceding claim, where the carrier comprises water, or is a mixture of water and an alcohol.
22. The flibric softener composition according to any preceding claim, further comprising a viscosity modifier.
23. A substrate impregnated with the fubric softener composition of any preceding claim.
24. The fabric softener composition according to any one of Claims 1-19, where the carrier is a bulking agent in dry powder form, further comprising at least one processing aid.
25. The fabric softener composition according to Claim 24, where at least one pmcessing aid is a polyoxyalkylene compound.