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Volume 89 Issue 4 | pp. 12-17
Issue Date: January 24, 2011

Cover Stories

Goodbye, Phosphates

Struggling automatic dishwasher detergent manufacturers turn to chemical industry for help with phosphate-free formulas
Department: Business
News Channels: Environmental SCENE
Keywords: detergents, automatic dishwashers, phosphates
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TEA TIME
Henkel’s automatic dishwasher detergent lab tests for tea-stain removal.
Credit: Henkel
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TEA TIME
Henkel’s automatic dishwasher detergent lab tests for tea-stain removal.
Credit: Henkel

On July 1, 2010, major cleaning product manufacturers finished removing phosphates from all home automatic dishwasher detergents sold in the U.S. The reformulation, the result of new laws in 16 states, was heralded as a win for the environment.

Unfortunately for companies marketing automatic dishwasher, or ADW, detergents, the story didn’t end there. Although fish might be happy that there are now less phosphorus-fed algae in rivers and lakes, consumers aren’t happy with many of the new phosphate-free products.

For an idea of what people are thinking, take a look at the website for Procter & Gamble’s Cascade, by far the leading brand name in U.S. ADW detergents. P&G’s high-end single-dose tablets continue to garner good reviews. But the firm’s workhorse ADW powders and gels are getting slammed. Comment pages that a year ago were filled with praise for Cascade’s effectiveness now brim with invective from unsatisfied users.

Typical is a consumer from Rose City, Mich., who wrote last month that “I shudder when I see the name Cascade. This product never should have hit the market!” Or Gerry from northwestern New Jersey, who wrote on Dec. 30: “I would like to be reimbursed for the 9.68-lb box of useless powder—not to mention the cost of replacing my coffee cups and glasses! You’ve permanently lost another customer.”

P&G consumer care representatives bravely respond to many of the angry posts. Often they note that, because Cascade products are now phosphate-free, consumers who live in areas with hard water might experience filming or spotting on their dishes. They suggest that dissatisfied customers try one of the single-dose products.

Although the reformulation has been a setback for P&G, it’s a business opportunity for companies that supply ingredients to P&G and other detergent makers. Chemical company R&D labs are feverishly at work developing new products to help fill the gap that was created when phosphates were removed from ADW detergents.

Added to U.S. dishwasher detergents at up to 35% by weight, sodium tripolyphosphate (STPP), the main detergent phosphate, was something of a wonder ingredient, helping to maintain pH, remove food and grease, inhibit corrosion, and suspend insoluble dirt. For the consumer, its main visible benefit was to reduce spotting and filming by sequestering calcium and magnesium ions in the wash water.

Now, with phosphorus levels limited to 0.5%, ADW detergent formulators are struggling. “The removal of phosphates was a paradigm shift that basically put all formulators back to the same level,” says Alfred Wong, global marketing and development manager for fabric and cleaning applications at AkzoNobel Surface Chemistry. Zeolites, the go-to replacement when, starting in the 1980s, phosphates were removed from laundry detergents, leave residue on dishware. Alternatives such as citrates are expensive and don’t work as well.

CLOSE EYE
A BASF scientist inspects a just-washed glass for residues, lime scale, and smears.
Credit: BASF
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CLOSE EYE
A BASF scientist inspects a just-washed glass for residues, lime scale, and smears.
Credit: BASF

“Phosphates are very effective, available in multiple forms, compatible in liquid and solid formulations, and cost-effective. There is no ‘one size fits all’ solution,” acknowledges Gary Dee, business director for personal and home care at BASF’s North American care chemicals business.

P&G’s tribulations with the new formulas have provided an opening for competitor Reckitt Benckiser. In September 2010, two Reckitt products—Finish Quantum tablets and Finish Powerball tablets—knocked Cascade Complete tablets out of first place and into third in a Consumer Reports magazine test of the new phosphate-free detergents. Still, Finish Quantum’s overall score of 79 was noticeably lower than the 89 given to the phosphate-containing Cascade Complete a year earlier.

For Reckitt, the process of going phosphate-free in the U.S. started in a laboratory in Ludwigshafen, Germany. Although Americans know the consumer products giant best for brands such as Lysol and Woolite, it’s also the number one ADW detergent maker worldwide.

Harald Magg is Reckitt’s global R&D director for dishwashing. At the firm’s Ludwigshafen labs, he directs a group of 80 people who do nothing but develop ADW detergents and test them in 150 dishwashers imported from around the world. Adjacent to the labs is a giant kitchen where researchers prepare—and sometimes purposely burn—foods from multiple ethnic origins.

Reckitt’s first experience with phosphate-free ADW products was in the 1990s, when a few European companies removed STPP, mainly in Germany, as part of a “green” marketing campaign. Consumers eventually revolted, and phosphates were reinstated. “We learned a lot about how complicated it is to find substitutes for phosphates,” Magg recalls.

His team learned, for example, that STPP can’t be replaced with a single magic bullet. “You need a clever and tricky combination of other ingredients,” he says. Indeed, of the ADW products on the U.S. market, Finish Quantum tablets boast one of the lengthiest ingredient lists. Magg points to sodium citrate; polyacrylates; and tetrasodium etidronate, a phosphonate, as being key elements in the phosphate replacement package.

Competing brands also contain many of the same ingredients, he acknowledges. “It’s not the ingredients themselves but the right cocktail that is the secret,” Magg says. “Sometimes little differences in the ingredient system can lead to big changes in film buildup over time.”

That’s where testing comes in. At its laboratories, Reckitt puts new detergent formulas through as many as 30 wash cycles to test for spotting and filming on dishware. After lab tests, the company moves to in-home consumer tests that last up to three months in the country where the detergent will be sold. “The best lab test can never substitute for a real consumer test,” Magg notes.

Product form is also important. Quantum tablets contain three chambers separated with dissolvable polyvinyl alcohol film. According to Magg, the chambers isolate incompatible ingredients and then control their release in the dishwasher. For example, Quantum’s center chamber opens later than the others to release ingredients that help prevent calcium deposition, he adds.

In fact, the top six products in the Consumer Reports test are all tablets of one sort or another. In contrast, consumer complaints logged on the Cascade website relate mostly to traditional powders and gels.

Industry players say the effectiveness—and price—divide between first- and second-tier products has widened in the postphosphate era. In the past, any detergent with enough STPP would perform pretty well, says a cleaning products formulation expert who asked not to be named for fear of alienating clients. “Today, there’s a lot more difference between the products than there used to be,” he says. “Everybody’s going very different routes.”

ADW gels, which grew in popularity with U.S. consumers in recent years, have become particularly hard to formulate, observers say. Of the five gels in Consumer Reports’ test of 24 products, four were at the bottom of the list, including Cascade with Dawn gel, a big seller for P&G.

BASF’s Dee explains that most gels contain chlorine bleach as a primary ingredient. Enzymes and surfactants typically aren’t compatible with bleach, but their absence didn’t matter when the formulas were loaded with phosphates. Now, with phosphates gone as well, performance is suffering. Dee sees a better future for enzyme-based gels, which can host surfactants, polymers, and organic chelants to enhance performance.

Even traditional powders aren’t faring well in phosphate-free form. Cascade with Dawn powder—which together with Cascade with Dawn gel is the top-selling ADW brand in the U.S., according to market research firm SymphonyIRI—was ranked 14 out of 24 by Consumer Reports and generally gets lambasted on the Cascade website.

Others in the industry give P&G credit for continuing to host online consumer reviews in the face of all the negativity. Still, they question why the Cascade formulas don’t include phosphonates, film-fighting chelating agents that contain phosphorus but are effective at low enough levels that the 0.5% threshold isn’t exceeded. P&G didn’t respond to questions from C&EN, although one source suggests the company is avoiding them to be completely phosphorus-free.

In addition to phosphonates, chemical companies are promoting a host of other ingredients aimed at helping detergent manufacturers bridge the phosphate gap. Chelating agents, dispersant polymers, surfactants, and enzymes are all being bandied about as the key to achieving phosphatelike performance in ADW detergents.

“The palette of available technologies is changing almost daily,” the formulation expert says. “Everybody is looking for the next miracle ingredient.” He says he tries to keep an open mind but cautions that a lot of “fu fu dust” is being promoted by corporate marketing departments.

BASF is confident that methylglycine­diacetic acid, a chelating agent it sells as Trilon M, will be an effective and biodegradable part of phosphate-free formulas. Dee says the company placed a big bet on Trilon M back in 2006 when legislation limiting or removing phosphates in U.S. ADW detergents started to look inevitable. The firm began building a plant in Germany in 2008 and completed it early last year.

Trilon M wasn’t in any of the products tested by Consumer Reports last summer, Dee says, but detergent industry customers are starting to incorporate it into second-generation formulas. Indeed, the ingredients list posted on P&G’s website shows that methylglycinediacetic acid is in Cascade Complete tablets.

Trilon M isn’t a drop-in replacement for STPP, Dee acknowledges, but he says it works effectively with other ingredients such as acrylic polymers and surfactants, both of which BASF sells. The firm’s Plurafac SLF180 nonionic surfactant is a longtime ADW staple that also performs in the phosphate-free formulas, he says. And Plurafac LF900 can be used in multifunctional detergents or stand-alone rinse aids to reduce spotting.

AkzoNobel also markets polymers, surfactants, and chelating agents to the ADW detergent industry. The firm’s challenger to Trilon M is glutamic acid diacetic acid, a new biodegradable chelating agent that it markets as Dissolvine GL. Derived from monosodium glutamate, a product of sugar fermentation, it shows up on the ingredients lists for Cascade Complete gel and Reckitt’s Finish Gelpacs.

AkzoNobel’s Wong says that the company has been working with environmentally conscious companies on zero-phosphate ADW formulas for a number of years. Akzo launched its big U.S. push in 2007, a year before two Washington state counties set a 0.5% limit on ADW phosphorus and started the ban movement rolling.

Like Dee at BASF, Wong says multiple ingredients are necessary to replace phosphates. Akzo is promoting its new Alcoguard hybrid dispersant polymers as companions to Dissolvine GL. The Alcoguard line was created by “hybridizing” a polysaccharide backbone with synthetic monomers. Both ingredients thus are derived at least in part from renewable resources.

Biodegradability has long been a weakness of detergent polymers, which are effective in small quantities but don’t degrade well in the sewage treatment process. At Cleaning Products 2010, a conference held in November by Intertech Pira, Akzo scientists touted Alcoguard H 5240, a hybrid polymer that boasts 65% biodegradability along with film and spot reduction equal to or better than that of fully synthetic polyacrylates.

Rivertop Renewables, a start-up company based in Missoula, Mont., hopes its new chelating agent, glucaric acid, will soon join Trilon and Dissolvine in ADW detergent formulas. Rivertop was launched in 2008 on the basis of work conducted by Donald E. Kiely, a University of Montana chemistry professor. The firm is headed by James R. Stoppert, a one-time Dow Chemical executive who has worked for a number of renewable-chemical start-ups.

Today, glucaric acid is stocked mainly by laboratory chemical supply houses. But Stoppert says Kiely’s carbohydrate oxidation process can yield large quantities from renewable resources at prices competitive with current chemicals. Working with contract manufacturers, he expects to be in production by the middle of this year.

Although Stoppert sees a wide variety of near-term applications for glucaric acid and its derivatives, he says Rivertop’s first target market will be manufacturers of dishwasher detergents, both for institutional and home use. When bridged by oxoanions, glucaric acid forms a complex that is structurally similar to ethylenedi­amine­tetraacetic acid and is far superior to sodium citrate at sequestering calcium, Rivertop claims.

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“We’ve got customers saying, ‘As soon as you build it, we will buy it,’ ” Stoppert says of Rivertop’s planned facility. “People are doing other things to get around phosphates, but no one seems to be satisfied.”

Acrylic polymers, Dow Chemical’s answer to the phosphate problem, have been around for years. Nilesh Shah, R&D director for Dow’s home and personal care business, explains that Rohm and Haas, which Dow acquired in 2009, developed replacements in the mid-1990s when ADW detergent makers were mulling phosphate-free formulas. In the end, though, they stuck with STPP, and the polymers languished on the shelf.

Rohm and Haas revived the program in 2007. Now, Shah calls Dow’s Acusol 425N copolymer the most widely used dispersant polymer in phosphate-free ADW products.

Polymers and chelants are generally included in ADW formulas in tandem. As Shah explains, small-molecule chelants such as Trilon M or Dissolvine GL work on a stoichiometric basis: One chelant molecule bonds with one metal ion. Polymers, on the other hand, have multiple bonding sites per chain. They are good at surrounding a growing crystal nucleus and keeping it from depositing onto dishware.

“You generally don’t see one in the absence of the other,” he says. “Especially when water hardness is high, you are forced to bring many tools to bear.”

Protease and amylase enzymes, long a part of ADW detergent formulas, are now doing extra duty in many of the new phosphate-free products. Rather than sequester metals in the wash water, enzymes degrade organic matter that is stuck to glasses and dishes, explains Nelson Prieto, manager of customer solutions in the Americas for the enzyme maker Novozymes. Although they are not a direct phosphate replacement, by breaking down soils and making them more water soluble, enzymes do their share to help prevent filming and spotting, he says.

Prieto isn’t sure whether enzyme levels will rise in the no-phosphate era, but he does know that customers are requesting more applications development help from Novozymes. “Demand for enzyme work in this area has definitely increased,” he says.

Like many of the new ingredients, enzymes are expensive. Reckitt’s Magg says his labs assess a lot of phosphate replacements that the company doesn’t end up using because the resulting detergent would be prohibitively expensive for the consumer.

Balancing cost and effectiveness is especially tough when trying to create a formula for regions with hard water, Dow’s Shah adds. “To put in the right level of dispersant and offer the product at the right price is a real challenge for our customers,” he acknowledges. One potential solution is Dow polymer chemistry, still being tested in the lab, that extends the effectiveness of expensive replacements for phosphates, Shah says.

In Europe, Thomas Müller-Kirschbaum argues that the solution is keeping phosphates in ADW formulas. Müller-Kirschbaum is senior vice president for R&D, technology, and supply chain with the laundry and home care business of Henkel, which markets the Somat brand of ADW detergent. He breathed a sigh of relief late last year when the European Commission left ADW detergents out of a proposed ban on phosphates in laundry detergents. Explaining the exemption, the commission noted that “technically and economically feasible alternatives are not yet available throughout the European Union.”

Europe’s ADW detergents are more sophisticated—and expensive—than those in the U.S., Müller-Kirschbaum explains, in part because most of Europe’s water is harder. Tablets dominate the market, and most brands make multiple claims related to water softening, odor reduction, shine, and etch inhibition.

Henkel’s European laundry detergents are already phosphate-free, but its ADW detergents contain as much as 40% phosphate, Müller-Kirschbaum says. He sees them as environmentally superior to phosphate-free formulas because they don’t require as many polymers and other nondegradable ingredients. Moreover, ADW detergents account for only 6% of phosphorus emissions to Europe’s rivers and lakes. “We think phosphate-containing formulas are the most sustainable formulas,” he says.

Henkel already sells reduced-phosphorus products in Italy for regulatory reasons and in France on a voluntary basis. And the company is prepared to launch virtually phosphorus-free detergents in other markets if necessary. Sweden, where Henkel has no ADW business, has already said it will limit phosphorus levels in ADW detergents to 0.5% on July 1. But Müller-Kirschbaum warns that such products just won’t work as well as ones that contain phosphates.

Reduced performance is pretty much what happened in the U.S., Reckitt’s Magg acknowledges. This is why, as soon as Reckitt launched its phosphate-free Quantum and Powerball products, Magg’s team began working on even better detergents that fully close the gap. “I think we are close,” he says, “but we are never satisfied with being close.”

 
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