Phosphate-free Automatic Dish Detergents
Cognis researchers explain why formulators don’t have to settle for poor performance when creating an ADD that’s good for the environment.
Patricia Rodríguez Pérez and Teresa Alexandre
As was the case with laundry detergents a few years ago, phosphates are now being banned from automatic dish detergents (ADDs) as in-creasing concerns about their impact on the environment have led authorities to prohibit their use in this application. In addition, more consumers are embracing a “greener” lifestyle and opting for products that contain environmentally sound raw materials, while remaining unwilling to compromise on performance. As a result, marketers continue to search for phosphate alternatives for use in ADDs that deliver the same performance as phosphates.
This is no easy task, however, as phosphates have many functions in ensuring that tableware is properly cleaned and rinsed. A substitute could weaken a product’s cleaning and particularly rinse performance. Studies now confirmed that Dehypon GRA, an effective granular rinse aid surfactant, can be used in multifunctional phosphate-free ADD formulations to guarantee brilliant results at the rinsing stage.
Multifunctional ADD—often called “x”-in-1 detergents— have become very popular as part of the convenience trend. These products add value for the end-user as they combine cleaning and protection systems with rinse surfactants and water softeners.
Each ingredient in a multifunctional ADD product performs a specific function to ensure clean and spotless tableware. Phosphates, generally in the form of sodium tripolyphosphates (STPP), have traditionally played a key role in ADD products as they are versatile and deliver good results.
The Phosphate Dilemma
Phosphates carry out several functions in ADD products. They sequester hard water ions, such as magnesium and calcium, to ensure efficient cleaning and rinsing for streak-free and spotless tableware. In addition, phosphates disperse dirt particles, suspending them in the water so that they are easy to remove from the tableware. They also maintain an alkaline pH, which is necessary for surfactants and other dishwashing components to perform at an optimum level.1
Although phosphates have been widely used as ingredients in ADD products, they are said to make a significant contribution to the eutrophication of water. This leads to immoderate plant growth and subsequent decomposition, disturbing the natural balance of organisms, and degrading water quality.2 For this reason, countries such as the U.S. and Canada are banning the use of phosphates in ADD products in an attempt to improve the condition of lakes and other bodies of water. In the U.S., for instance, it is expected that phosphates will be phased out from ADDs by July, 2010.
Environmental concerns, new regulations and bans on phosphates are driving ADD manufacturers to switch to more ecologically sustainable alternatives. Although it is important for them to know that a product has no negative effect on the environment, they want the guarantee that it will satisfy their customers’ demands in terms of performance, too. Therefore, it is not easy to replace phosphates in ADD products as there is no direct substitute for them. Alternative ingredients are expected to offer a comparable dishwashing performance (in terms of both cleaning and rinsing) to the one achieved when phosphates are used in ADD products.
Nowadays, it is possible to find many different phosphate-free ADD products in supermarkets. These products promise to get dishes squeaky clean. Some consumers believe that while phosphate-free products may be good for the environment, they are not as effective as regular phosphate-based products. But how good can the performance of phosphate-free products really be in relation to phosphate-based ones? Like cleaning performance, rinse performance is just as important when determining how effective multifunctional ADD products are.
Good rinse performance is translated into spotless and film-free tableware. Phosphates play an important role in guaranteeing that glassware and crockery will not be covered with spots or water streaks. Therefore, many formulators assume that not using these components in ADD products will deteriorate the rinse performance (Fig. 1).
To demonstrate its efficacy, a multifunctional phosphate-free (P-free) ADD formulation was tested against a multifunctional phosphate-based (P-based) formulation in terms of rinse performance. Both contained Dehypon GRA as a rinse aid additive and the phosphate-free formulation included citrate as a phosphate substitute.
A digital image analysis tool (DIAT) was used to evaluate the rinse performance of each formulation. A digital camera located inside the DIAT took pictures of the cleaned surfaces. These were analyzed by specially developed software, so that filming and spotting in different kinds of substrates could be measured objectively (Fig. 2).3
After using the DIAT to evaluate the rinse performance of the multifunctional phosphate-free and phosphate-based formulations, the results showed that phosphate-free formulations can deliver a comparable performance to phosphate-based ones. The results are shown in Fig. 3.
To measure if the multifunctional phosphate-free formulation delivered the same rinse performance as well-established multifunctional phosphate-based market products, the formulation was tested against two market benchmarks (products A and B). The results can be seen in Fig. 4.
Phosphates are important ingredients in ADD products because they ensure effective cleaning and rinsing of glassware and crockery. But due to the impact they have on the environment and new regulations and bans of their use in ADD products, the market continues to look for sustainable alternatives that can offer consumers the same dishwashing performance they get from using phosphate-based products.
Today, effective rinse aid surfactants such as Dehypon GRA enable manufacturers to develop multifunctional phosphate-free products that deliver excellent rinse performance and satisfy consumers’ demands for sparkling clean dishes.
1. CEEP, 2007. Centre Européen d’Etudes des Polyphosphates. Phosphates in Auto- matic Dishwasher Detergents. August 2007. p.1-3. Available at http://www.ceep-phosphates.org.
2. European Commission, (2007). Commission Report on phosphates in detergents. April 2007. Brussels. http://ec.europa.eu/ enterprise/chemicals/legislation/detergents/index_en.htm
3. Böhme, C., Both, S., Frischemeier, R. & Weuthen, M., (2005). Maschinelle Geschir-reinigung–Entwicklung einer objektiven Messmethode zur Beurteilung der Klarspülleistung. SÖFW Journal. Sonderdruck aus Oktober 2005, 131, p. 1-5