The invention relates to textile conditioning compositions comprising especially textile softening and antistatic agents characterised by an unusually low content of cationic textile conditioning agent.
Textile conditioning, especially softening compositions in the form of aqueous dispersions are well known, and are primarily intended to be added to the last rinse liquor in a conventional clothes-washing process. Most of such compositions currently on the market comprise a fairly low concentration, for instance about 3-10%, of a cationic textile softener or of a mixture of more than one, together with relatively minor amounts of emulsifiers, and with aesthetic additives such as colour and perfume. These compositions are used at quite low concentrations in the treatment bath, for instance about 0.25% by weight.
It is also known that certain nonionic, poorly water soluble or insoluble, compounds such as sorbitan and glycerol esters are effective softeners, but they are not substantive and are not effectively applied to the fabrics in a rinse or like bath. It is known yet again that combinations of these nonionic components with a cationic surfactant can cause them to be deposited upon fabrics in a rinse or like bath.
Now at present nonionic softeners are considerably cheaper than cationic and they seem likely to remain so in the foreseeable future. Therefore use of nonionic-cationic mixtures of relatively low cationic content is highly desirable since they can permit improved products to be made for the same cost. However, such mixtures, though effective in pure water, are generally not very effective in practical rinse liquors. The reason appears to be the presence in the rinse liquors of traces of anionic detergent carried through from the wash, typically 10-20 parts per million in a final rinse, and these combine with cationic conditioning agent to form complex molecules thereby reducing the performance. In wholly cationic-based softeners this loss of effective cationic active component is undesirable, but may be tolerable. In mixtures of nonionic and low levels of cationic conditioner, the loss becomes greater in proportion to the total cationic conditioner present and is serious. The use of relatively water soluble cationic surfactants has been suggested to act as scavengers for anionic detergent (see U.S. Pat. No. 3,974,076) but these need to be used at considerable levels.
It has now been found that this scavenging function can be performed by very low levels of polymeric cationic salts. This has made it possible to provide effective textile conditioning, especially textile softening and antistatic, compositions based on nonionic textile softeners with a low level of cationic surfactant to render them substantive to the fabrics. Furthermore, quite low levels of some of these polymeric cationic salts have been found unexpectedly to provide softening performance themselves in the presence of cationic surfactants thereby permitting a further reduction in the other softener components of textile softening compositions.
Textile softening and ironing assistants containing combinations of nonionic and cationic softeners containing relatively high levels of cationic dextrin are disclosed in German Offenlegungsschrift No. 2,724,816. Furthermore, Belgian Pat. No. 844,122 describes textile conditioning compositions containing nonionic softener and low levels of cationic surfactant and suggests the use of certain oligomeric polyamine salts as cationic carrier materials for the nonionic softener.