Keeping up with detergent chemistry

By Mike Lafferty

In This Section

August 2010

The detergent industry is highly competitive, mostly recession proof, and, thanks to chemistry, always changing ever so slightly. It has been years, however, since cleaning chemistry has been the driving force in detergent innovation. Instead, the environment rules in laundry rooms and kitchens. In the United States, for example, on July 1 (2010) 15 states virtually banned phosphates from automatic dishwashing products. That will produce consternation in kitchens-dishes don't seem to come quite as clean without phosphorus, and detergent chemists are trying to figure out what to do.

For clothes, however, the question of "How clean is clean?" had been answered by the 1980s-at least in high-end products sold in North America, Western Europe, Japan, and Korea.

"The end point for formulators for laundry detergents is consumer satisfaction. Can they improve on that? Only marginally; garments are clean and probably smell fresh for probably 90% or more of consumers," said Warren Schmidt, a retired Shell chemist, who is now an industry consultant. "Advancement is driven less by soaps and cleaning and more by bleach and bleach activators and perfumes. Often, the number one way people tell if laundry is clean is, does it smell fresh."


Today, detergent manufacturers are pushing super-concentrated formulae to reduce packaging and transport costs, changes that address environmental concerns of consumers and economic concerns of formulators rather than new worries about defeating dirt.

Modern detergents are mixtures of surfactants (cleaning chemicals), builders (water softeners), bleaches (to whiten and remove stains), enzymes (to break down soils to simpler forms for removal by detergent), optical brighteners (to create a whitening effect), polymers (to prevent soils from resettling after removal during washing), and fillers. Worldwide, these chemical mixes vary. American consumers prefer liquids to powders by a 60-40 margin and the number of powdered detergents available in the United States has shrunk.  In contrast, Europeans have a greater choice in detergents because of a wider range of consumer preferences, due in part, to there being many more nations and cultures in Europe. Still, European detergents are more often powders and tablets, except in France. Whereas 60% of the overall European market is powders and tablets, in France, most consumers prefer liquids.

Detergents in Western Europe and North America also have more surfactants, bleach, polymers, and enzymes than those in Africa, Asia, and Latin and South America. In developing nations, manufacturers walk a fine line between effectiveness and expense.

"To produce a product for this market is expensive and the people can't buy expensive," said Heliana Kola, a chemist at Columbus, Ohio, USA-based Battelle's detergent analysis program. "In Latin America, the Philippines, India, they still have a lot of work to do. These countries are poor so they use cheap ingredients. Western Europe, North America, Japan, and Korea are where you find modern detergents-where they care about performance of the product but also care for the environment."

Battelle scientists track household cleaning and laundry detergent formulations worldwide. Water-polluting phosphates, for example, have been chased completely from laundry detergents in North America, Western Europe, Japan, Korea, and China, replaced by zeolite, a mineral containing aluminum and silicate. They are also being phased out of products in Eastern Europe, Kola said, although they are still used in India and other Asian and Pacific nations. Even name-brand detergents can vary from region to region. "A product sold in Germany is not the same as in Turkey," Kola said.


Detergents actually have a history as long as that of civilization. One of the first things people wanted after they set up house was, apparently, clean clothes. Ancient Babylonians and Egyptians had recipes for making soap. The Romans claim rights to the name when, according to legend, rain washed down the slopes of Mount Sappo, a mythical spot where animals were sacrificed. The rain washed the fat from the sacrificed animals into the Tiber River, along with alkaline ashes from the sacrificial fires. There, washerwomen found the mixture helped get their clothes clean. Animal fat and ashes remained the basis for soap making for thousands of years.

Modern detergents were spawned in 1916 when the first commercial synthetic surfactant was made in Germany from coal tar to get around the shortage of animal fats during World War I. Chemicals builders, which improve the cleaning ability of surfactants, were next to be added. They chelate calcium and magnesium ions in hard water, thus maintaining or enhancing the cleaning efficiency of the surfactant. Later inventions included optical brighteners-enzymes-that attach to fabrics. Now, detergents have up to six enzymes, each one with a particular function or stain target. Further enzyme development has been motivated by environmental concerns-in this case the desire for detergents to perform in a cold-water wash.


Ironically, for such a competitive business, there are few secrets. Everyone wants to know what the competition is doing. Although some large companies have their own testing labs, many companies choose not to spend the money on a lab devoted only to analyzing the competition. In the only program of its kind, Battelle provides that service to detergent manufacturers and to companies that supply the chemical ingredients.  

"By sharing the expense, companies can get the information at approximately 25% of the internal cost of running their own laboratory," said Franco Pala, who heads the operation at Battelle's Duxbury, Massachusetts, USA, lab. Competitors especially want to know trends. Are companies using a particular surfactant? Are they using more or less bleach or enzyme? "A detergent formulator needs to know what's in [a new name-brand product] almost immediately. They need to know in weeks, not months," Pala said.

In fact, Battelle does have an Early Warning System that, upon a client's request, provides the chemical composition of a significant new detergent product in short turnaround time, Pala said.

The detergents program was originally started at Battelle's former Geneva Research Centre, in Switzerland, when European companies wanted to know what their competitors were doing to reduce levels of water-polluting phosphates in detergents.

Battelle scientists have noted that Japan is now a leader in detergent innovation. The switch to concentrated formulations in high-end detergents actually began in Japan in 1987. Concentrates now completely dominate the market in developed countries, with super-concentrated liquid products entering the American market in 2006. Powder concentrates, in turn, spawned concentrated liquids. Today, compact powders are spreading into developing regions such as Latin America, Eastern Europe, and Southeast Asia.


The next major environment push may be a swing away from the petroleum-based surfactants that have dominated synthetic detergents since their invention-again in high-end products. Not many people think about the source of the cleaning agents in their soaps and detergents but retailers do, and "all natural" is increasingly "in" as a marketing strategy, at least in niche products.

"They're very interested in that claim. Price is not really an issue," said Schmidt.

For laundry detergents, the two most significant factors in the American market in the coming decade will continue to be consumer desire to use less energy-to launder their clothes in warm or even cold water-and regulations forcing manufacturers to build high-efficiency washing machines. Pressure to remove water-polluting phosphates from detergents also will continue.  

Sodium tripolyphosphate (STPP or phosphate) has been the main cleaning agent in many detergents and household cleaners for decades. Phosphates do a great job by helping surfactants break down grease and remove stains, but they are difficult to remove from wastewater and often end up in rivers and lakes, where they promote algal growth and, eventually, eutrophication. Zeolite, the substitute for STPP, was not effective by itself at first, but scientists resolved the problem by combining it with a number of other ingredients such as sodium citrate and silicate.

This brings us back to the July phosphate ban in automatic dishwashing detergents. Removing phosphates from automatic dishwashing detergents has lagged because it has been difficult to come up with an effective replacement. Dishwashing-machine detergents contain only 1-2% surfactant because, otherwise, they would produce too many suds. Phosphate is a really key ingredient to enhance cleaning efficiency. In contrast, hand-dishwashing detergents contain up to 30% high-foaming surfactants. Making a lot of suds in the sink is part of the cleaning process, but using a hand-dishwashing detergent in an automatic dishwaster would produce a suds explosion.

Mike Lafferty, the retired science writer for The Columbus (Ohio, USA) Dispatch newspaper, is a freelance journalist specializing in science, agriculture, environment, and education articles for newspapers, magazines, and electronic publications. He also is editor-in-chief of the Ohio's Natural Heritage book and, most recently, co-author of the book, Ohio's Education Reform Challenges: Lessons from the Frontlines.