Most people are aware that washing and wearing clothes is not good for them. Clothes suffer damage due to abrasion in the wash, particularly around seams and hems. On dark cellulosics (such as black jeans, for example) this damage exposes fibrillated regions of the textile which scatter light differently than undamaged regions.
While the damaged regions may have lost relatively small quantities of dye, they are very easy to perceive and produce a strong visual impact. It has been suggested to reduce the incidence of such damage by using lubricating agents in wash liquors. However the skilled worker is faced with a problem when choosing the right lubricant. Prior proposals have included acrylic materials, dextrans, oily and waxy materials.
Hydroxy ethyl cellulose (HEC) is widely commercially available and is well known as a thickener in a range of surfactant-containing products as well as in paints and other coatings. It is generally produced by the treatment of cellulose with ethylene oxide to give materials with a specified degree of substitution. Related materials are known which comprise other short alkyl chain substituents (typically C2-4). Hydroxy-alkyl derivatives of other beta 1-4 linked poly-saccharrides are also known.
In order to bring about viscosity changes HEC is typically present at levels of 1-2% wt on liquor, depending on the molecular weight of the polymer. It is known that bulk viscosity increases in a wash liquor can have beneficial effects on fabrics being laundered, as the increase in viscosity reduces certain fabric-fabric interactions which can cause degradation of the fabrics through such mechanisms as abrasion etc. However, viscosity increases have negative consequences as well. In particular, they can significantly reduce cleaning.
WO 99/14295 discloses compositions and methods for fabric treatment to impart appearance and integrity benefits, which utilise cellulosic based polymers having ether substituents on the hydroxyl groups of the glucose rings. The substituents take the form —OR where R is one of:    a) —H and —C1-4 alkyl (i.e. an unmodified hydroxyl or an alkyl ether,    b) —(CH2)y—CO—OZ (i.e. a carboxyl terminated alkyl ether which can be esterified with another group, or    c) —[Et.R20]n-RH. In these compositions n is 0-5 and RH comprises an alkyl chain, so this comprises either a poly-oxyethylene linker to the alkyl chain or simply the alkyl chain connected to the backbone via an ether linkage.
The benefits disclosed in WO 99/14295 are believed to be obtained by the active component, i.e. the ether, associating itself with the fibres of the fabric to reduce or minimise the tendency for the fabric to deteriorate. It is believed that in many cases the association with or ‘recognition’ of cellulose by another beta 1-4 chemical species involves an interaction between the backbones of the cellulose and the beta 1-4 polymer.
None of the formulations mentioned above with reference to WO 99/14295 comprise a simple hydroxy alkyl derivative of the saccharide backbone. It has been thought that these materials would not associate with cellulose because the hydroxy alkyl groups would interfere with the backbone-backbone interaction that is believed to be necessary for cellulose recognition.
Several other documents relate to the use of hydroxy-ethyl cellulose (HEC) in laundry detergent products and processes. While several of these mention that HEC can bring cleaning benefits none address the issue of lubrication benefits.
U.S. Pat. No. 2,602,781 discloses the use of hydroxy-ethyl cellulose to enhance soil removal by synergy with the surfactant. Levels of HEC taught are between 1 and 63%, (preferably between 5 and 57%) by weight of product and the stain used was a mixture of carbon black and mineral oil. Tests would probably have been performed on white cloth (standard ‘Indian Head’ muslin) as they concerned removal of soil.
EP 467,485 is concerned with the provision of softness and antistatic benefits. The formulations comprise alkyl cellulose ethers selected from methyl cellulose, hydroxypropyl methyl cellulose and derivatives of hydroxyethyl cellulose wherein the terminal hydrogen of the hydroxyethyl group is replaced with an alkyl chain having 10-24 carbon atoms.
GB 1,537,287 discloses compositions which comprise 0.1% to 3% of a component selected from alkyl cellulose ethers, hydroxy-alkyl cellulose ethers and hydroxy-alkyl alkyl cellulose ethers. Hydroxy ethyl cellulose DS hydroxy ethyl 1.2 is mentioned (see page 7 lines 4ff). Closely related case U.S. Pat. No. 4,174,305 discloses cellulose based soil release polymers and mentions hydroxy-ethyl cellulose (column 6, lines 24ff). Both patents illustrate soil removal with dirty motor oil. Again, this patent contains no examples of the treatment of coloured cloth with HEC.
EP 0 331 237 discloses the use of a hydrophobically modified nonionic cellulose ether in a fabric softening composition. Hydroxy-ethyl cellulose is mentioned in the body of the patent but it is present only as an example of the substrate that is then modified to form the hydrophobically modified cellulose derivative. Preferred are derivatives of methyl, hydroxyethyl or hydroxypropyl cellulose which have been modified with a C10 to C24 hydrocarbon.
U.S. Pat. No. 6,200,351 B1 discloses the use of a soil release polymer based on a copolyester of a dicarboxylic acid and a diol or polydiol in the surfactant-free, pre-treatment step of an institutional washing process. Hydroxy-ethyl cellulose derivatives are mentioned (see colum5 lines 55ff).