The present invention pertains to the bleaching of household laundry in a two-stage wash cycle.
Formulations for washing household laundry essentially are currently available, which are described as "complete" and which contain both agents with detergent action and agents with bleaching action. The most common of the former agents are the surface-active agents, sodium polyphosphates and especially sodium tripolyphosphate. The per salts, and especially sodium perborate, are most common among the agents of the second type.
These per salts or peroxyhydrates are relatively expensive carriers of active oxygen, and any improvement of their bleaching effect that can be manifested is an undeniable economic gain.
Such an improvement is to be sought especially at a low temperature, 70.degree. C. or less.
In fact, the per salts are no longer effective enough under these conditions, and it is necessary to add so-called activating compounds to them, whose expense partially reduces the gain attributable to the reduction of the thermal energy consumption.
The activators can be chemical compounds of diverse nature. However, such compounds as, e.g., tetraacetylethylenediamine (TAED),.alpha.-acetoxy-.alpha.-methyl-N,N'-diacetylmalonamide, which is the subject of French Patents published as Nos. 2,363,541 and 2,363,629, cyanamide and its derivatives, which are the subject of a French Patent published as No. 2,340,371, are most widely used industrially and are most commonly mentioned.
USPTO Backgrounds
USPTO Backgrounds