Improvement of Bleaching Power in Phosphate-free Automatic Dishwashing (ADW) Products
Time: 2:40 pm - 12:00 am
Bleaching power is a key area of cleaning performance of an ADW product, for instance for removing stubborn stains like tea. Large performance differences still exist between ADW products worldwide. Important factors influencing the bleach action are the bleach system used and the pH of the wash liquor.
The bleach system typically comprises a bleach compound, a bleach activator (e.g. TAED) and a bleach catalyst (e.g. Mn catalyst). A very important factor, besides performance level, is the robustness of the bleach system upon storage in the ADW product, especially at high temperatures.
The functions alkalinity and buffering capacity have been provided by phosphates. However, environmental considerations on the impact of phosphates in waste water led to the removal of these chemicals in ADW detergents. Alternatives chemicals providing these functions are necessary.
In this study, the bleach system sodium percarbonate / tetraacetylethylendiamine (TAED) /MnTACN was evaluated in combination with the builder layered sodium disilicate. The combination results in a significant improvement of bleach performance.
In addition, it is shown that the granulation and coating of the bleach catalysts with specific ingredients leads to improved flexibility and stability of bleach catalysts in ADW formulations.