Inorganic peroxygen compounds, in particular hydrogen peroxide and solid peroxygen compounds that dissolve in water with release of hydrogen peroxide, such as sodium perborate and sodium carbonate perhydrate, have been used for some time as oxidizing agents for disinfection and bleaching purposes. The oxidizing effect of these substances in dilute solutions depends greatly on temperature; sufficiently rapid bleaching of stained textiles in alkaline bleaching baths is obtained, for example, with H2O2 or perborate only at temperatures above approximately 80° C. At lower temperatures, the oxidizing effect of the inorganic peroxygen compounds can be improved by the addition of so-called “bleach activators,” which are capable of supplying peroxocarboxylic acids under the above-discussed perhydrolysis conditions and have become known in the literature for numerous proposals, chiefly from the substance classes of the N- or O-acyl compounds, for example reactive esters, polyacylated alkylenediamines, in particular N,N,N′,N′-tetraacetylethylenediamine (TAED), acylated glycourils, in particular tetraacetylglycouril, N-acylated hydantoins, hydrazides, triazoles, hydrotriazines, urazoles, diketopiperazines, sulfurylamides, and cyanurates, also carboxylic acid anhydrides, in particular phthalic acid anhydride, carboxylic acid esters, in particular sodium nonanoyl oxybenzenesulfonate (NOBS), sodium isononanoyl oxybenzenesulfonate, O-acylated sugar derivatives such as pentaacetyl glucose, and N-acylated lactams, such as N-benzoylcaprolactam. The addition of these substances allows the bleaching effect of aqueous peroxide baths to be increased sufficiently that the effects that occur at temperatures around 60° C. are already substantially the same as with the peroxide bath alone at 95° C.
In the context of efforts toward energy-saving washing and bleaching methods in recent years, utilization temperatures that are even appreciably below 60° C., in particular below 45° C., down to cold-water temperature, have also become increasingly important.
As a rule, the effect of the hitherto known activator compounds decreases perceptibly at these low temperatures. There has therefore been no shortage of efforts to develop more-effective activators for this temperature range. There have also been various proposals to use transition metal compounds, in particular transition metal complexes, to enhance the oxidizing power of peroxygen compounds or also of atmospheric oxygen in washing and cleaning agents. Among the transition metal compounds proposed for this purpose are, for example, salen complexes of manganese, iron, cobalt, ruthenium, or molybdenum, carbonyl complexes of manganese, iron, cobalt, ruthenium, or molybdenum, complexes of manganese, iron, cobalt, ruthenium, molybdenum, titanium, vanadium, and copper with nitrogen-containing tripod ligands, and manganese complexes with polyazacycloalkane ligands, such as TACN. A disadvantage of such metal complexes, however, is either that they possess in part a bleaching performance that is insufficient especially at lower temperature, or, if they have sufficient bleaching performance, that undesired damage can occur to the colors of the material to be washed or cleaned, and in some cases even to the material itself, for example the textile fibers.
It has now been found, surprisingly, that bleaching-active species that exhibit an outstanding bleach-intensifying effect, and that intensify the cleaning performance of washing and cleaning agents in particular with respect to bleachable stains, can be generated from organic mediator compounds by electrolysis.
A subject of the invention is accordingly the use of bleaching-active species, generated electrolytically from organic mediator compounds using a redox reaction, to intensify the cleaning performance of washing and cleaning agents, in particular with respect to bleachable and/or protein-containing stains, in an aqueous, in particular a surfactant-containing bath.
Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.