Sodium Citrate in ADWD
Automatic dishwashing detergent (ADWD) tabs are very popular and commonly used household detergents. Besides surfactants (rinse aid and grease dissolving), bleaching agents, and enzymes, builders form an essential part of ADWD formulations due to their ability to complex metal ions, e.g. calcium or magnesium cations thus softening the water and reducing lime scale deposits. Traditionally, phosphates, like sodium tripolyphosphate, have been used as the main builder ingredient in dishwashing detergents. Since their release into water induces excessive growth of algae and contributes to water pollution, regulations on phosphate limitations in ADWDs have been introduced in many countries. As a result, the search is on for natural and sustainable substitutes.
In this context, trisodium citrate has proven to be an ecologically friendly alternative. Within the last years, trisodium citrate has gained increasing popularity as excellent complexing agent and has established itself as a “green builder” in phosphate-free dishwashing detergents.
With regard to the requirements of modern ADWD systems, trisodium citrate represents an excellent combination of environmental friendliness and good complexing properties:
- Effective chelation of hard water ions, such as calcium, magnesium and metal ions
- Buffering the pH of the washing liquid
- Compatibility with other dishwashing detergent ingredients
- Readily biodegradable under aerobic conditions, but also under anaerobic waste water treatment conditions and in the natural environment
- Non-toxic to human health
- Free from phosphorous, and thus not eutrophic
Based on our vision "From nature to ingredients®" we at Jungbunzlauer aim to help our customers to manufacture healthier, safer, and more sustainable products and thereby contribute to the protection of both humans and environment. Jungbunzlauer offers two forms of trisodium citrate: trisodium citrate dihydrate (TSC) and trisodium citrate anhydrous (TSA). TSC is produced by complete neutralisation of citric acid, which is manufactured by fermentation of renewable carbohydrate sources. The anhydrous form, TSA, is obtained from the dihydrate crystals by removing the water molecules in a patented process without destroying the original crystal matrix. Both TSA as well as TSC show excellent flowability and tabletting characteristics including breaking strength, friability and disintegration time. These important properties provide great benefits to improve and optimise dry-mixing production processes of dishwashing powder and pressing of dishwashing tablets.
The anhydrous form, TSA, even provides additional advantages. Handling and incorporation of liquid or waxy surfactants often prove to be difficult and commonly lead to limitations in production and storage of ADWD formulations. Since TSA has a porous, sponge-like structure, the particles can be used as active carriers for surfactants, but also for other liquids such as perfumes, while remaining a free flowing powder. Moreover, the porosity enables the uptake of excess water and thus water sensitive ingredients like bleaching agents and enzymes are less exposed to moisture in the formulation. Also, by using TSA, less water is introduced into the detergent formulation and a lower dosage is needed in the final detergent.
In conclusion, Jungbunzlauer trisodium citrate is a sustainable and effective builder for environmentally friendly ADWDs in the form of tablets or powders. Moreover, the anhydrous form of sodium citrate provides an innovative, convenient way for the improved incorporation of liquid or waxy actives into dishwashing detergents.