Nitriles, bleach activators

FIGURE 16.10 Nitrile quats and liquid bleach activators. 

Sometimes other active ingredients may serve as additives as well and may generate additional benefits. For example, a combination of different bleach activators makes it possible to cover the full temperature range (see example for TAED + nitrile quat in Ref. 94) or spectrum of stains (see example for TAED-DOBA in Ref. 95) in the wash. 

As reported in literature, many bleach actives are chemically unstable in an alkaline detergent formulation if they are incorporated as a fine powder (see example for TAED in Ref. 102 or nitrile quats in Ref. 103). A further granulation step is therefore usually necessary to transform the fine powder obtained from spray drying into a stable granule. 

If extrusion is used, the base powder, consisting of the bleach active ingredient and optionally other additives, has to be mixed with a plasticizer. The easiest approach is to use water as the plasticizer, which is subsequently removed by drying (see example for DOBA in Ref. 114). In many cases, plasticizers are used that soften and melt at higher tanperatures (see example for nitrile quats in Ref. 115), but remain in the final particle. The plasticized product mixture is extruded through a perforated die to form cylindrically shaped strands. Typically, the diameter of the extrudates ranges from 0.7 to 2.0 nun. 

Seebach, M. et al., inventor, WO 03/078561 Ammonium nitriles and the use thereof as hydrophobic bleaching activators, Clariant, 2003. 

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