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 or navy ‘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 asked to choose 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 viscosity modifier 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 of the hydroxyl groups of the glucose rings with hydroxy ethyl groups. Related materials are known which comprise other short alkyl chains (typically C2-4). Other known materials are hydroxy-alkyl derivatives of other beta 1-4 linked poly-saccharrides.
In order to bring about viscosity changes cellulose ethers are generally required to be 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. They can significantly reduce cleaning.
WO 99/61479 discloses the use of hydrophobically modified cellulose ether in, for example, detergents.
WO 00/65015 discloses the use of cellulose-ether as a finishing agent, which is replenished during washes.
WO 98/29528 discloses the use of 0.1-8% wt of modified cellulose ether, which ‘associates with the fibres of the fabric being laundered’and ‘reduces the tendency of the fabrics to deteriorate in appearance’.