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					Chemical & Engineering News
January 29, 2007 Volume 85, Number 05 pp. 21-23



Special Delivery
Getting fragrance onto clothes presents a challenge for
detergent companies and their suppliers
Michael McCoy

CLOTHES SHOULD SMELL GOOD after they are washed, yet cleaning a garment
and keeping a fragrance on it usually are incompatible from the surfactant's perspective.

As Kumar Vedantam, director of technology and applications at Givaudan Fragrances,
explains, delivering fragrance to washed clothes faces a fundamental stumbling block. "In
the cleaning process," he says, "what you want the product to do is remove oily and
particulate soil that gets deposited on a substrate during use." Fragrances, however, are
also typically oily materials. "You expect your product to remove one set of oils and
deposit another," Vedantam says, "but the surfactant doesn't distinguish between them."




                                                                       Givaudan
Well-Stocked
Choosing the right aroma chemical is a big part of effective fragrance delivery.


Efforts to overcome this problem are yielding sophisticated solutions that belie how
mundane laundry is. Take for example a paper published last July by researchers from
Unilever and University College London's department of biochemical engineering, which
described biotechnology befitting high-end drug discovery (Biotechnol. Bioeng. 2006, 94,
625).

In the paper, the scientists describe a new, low-cost class of antibodies with affinity for
one or more molecular surfaces. But rather than lay out use of these antibodies in drug
delivery or therapeutics, the paper proposes adding them to detergent so they can
deliver perfume to laundry in the wash.

Although the antibody work is by no means commercial, it shows the extent to which
detergent companies such as Unilever are willing to go to coax fragrances and other
active ingredients to deposit on the surface of clothing rather than disappear down the
drain with the wash water. After all, consumers appreciate a pleasant-smelling bottle of
detergent, but it's the scent of a washed and folded garment that leaves a lasting
impression and creates a loyal customer.
Targeted delivery of fragrance and other cleaning product ingredients is being pursued by
four segments of the detergents industry: fragrance manufacturers, delivery technology
specialists, specialty chemical companies, and consumer product makers. All are aware
that their task is frustratingly quixotic.

Michael Popplewell, vice president of delivery and material technology with International
Flavors & Fragrances (IFF), puts the challenge this way: "You are trying to deliver a
molecule with a process that's really designed to remove molecules." As if that wasn't
enough, Popplewell notes a second challenge: After washing comes drying, often by
heating, and fragrance molecules tend to evaporate along with the water.

Faced with this pervasive loss of fragrance, the industry's first line of attack is to tailor
the scent molecules themselves. According to Popplewell, hydrophobic compounds are
more likely to deposit on clothes than hydrophilic ones, because they are less likely to
dissolve in the wash water. And high-molecular-weight molecules have the best chance
of surviving the clothes dryer.

But even with the most robust molecules, Vedantam notes, up to 90% of the fragrance
added to a detergent can be lost during washing. Givaudan and its competitors combat
this problem with proprietary fragrance molecules that possess what he calls high odor
value. These molecules give off a scent that is discernible even at nanogram or
microgram quantities, he says.

Dallas Hetherington, business manager for encapsulation and delivery systems at Alco
Chemical, a division of National Starch & Chemical, agrees that odiferous molecules offer
a degree of effectiveness. "But you still lose a great deal of fragrance down the drain,
which can get costly," he says. Plus, such an approach restricts the detergent formulator
to a limited palette of aroma chemicals.

Thus, the second line of attack is encapsulation, or some other form of molecular
tethering, to control the delivery of fragrance to clothing. For IFF, the main weapon on
this front is Celessence International, a British fragrance encapsulation company it
acquired in 2003.

Celessence's claim to fame is a controlled-release system that is applied to fabrics and
other substrates at the textile mill or garment factory. Fragrance releases gradually over
time as the products are used. For example, pillows marketed by the British retailer
Marks & Spencer retain their vanilla or lavender and chamomile scent thanks to
Celessence technology.

SINCE 2003, Popplewell says, IFF and Celessence researchers have modified the system
so it can be employed in rinse-off applications such as laundry detergents and fabric
softeners. He says a customer has launched a laundry detergent incorporating the
technology and that other applications are in the works.

At Givaudan, in-house R&D efforts have yielded a number of encapsulation and other
controlled-release technologies in recent years.

In 2003, the company launched Granuscent, an encapsulation technique that protects
volatile fragrance materials in a dry environment and then releases them upon contact
with moisture. Although its large particle size was designed for powdered laundry
detergents, Granuscent's biggest application has been in a completely different market
that Vendantam wouldn't disclose. An older encapsulation technology, Permascent, is
being used to protect fragrances in powdered detergents, he adds.

Releasing fragrance from a liquid medium is trickier, Vedantam acknowledges, because
soluble encapsulants can't be used. One Givaudan solution is a controlled-release system
based on liquid crystals composed of water, fragrance oil, and surfactant that have
properties halfway between a solid and a liquid.

IN DEVELOPMENT for about six years and the subject of three patents, the crystals
latch onto textiles in the wash, survive the drying process, and emerge to release their
fragrance over time. Customer feedback has been positive, Vedantam says, and
commercial launch is being readied.

A second new delivery system from Givaudan is a family of pressure-activated
microcapsules that release their scent from washed and dried garments in response to
movement or friction.

Vendantam says these materials are akin to the coacervation encapsulants used in
carbonless paper and scratch-and-sniff magazine inserts. But because Givaudan designed
them for laundry applications, they are able to withstand a high-pH environment and
exposure to enzymes and bleaches. They have successfully completed consumer tests
and are now in the scale-up phase, he adds.

Although fragrance companies such as IFF and Givaudan seem to be pursuing controlled-
release technology quite aggressively, Sam Shefer, vice president of Salvona
Technologies, argues that they are not necessarily the best sources of such rarified
know-how.




                                       Givaudan
The Nose Knows
Research executive Vedantam smells a towel washed with detergent containing a Givaudan fragrance
encapsulant.

Based in Dayton, N.J., Salvona is a specialist in developing and commercializing
ingredient delivery systems for food, health care, consumer care, and fabric and
household care. Early in his career, Shefer was a chemical engineering professor at
Massachusetts Institute of Technology. He later worked for biomedical and consumer
product companies, including IFF; nine years ago, he helped found Salvona.

Shefer says his review of controlled-release patent literature of the past five years found
an unimpressive level of activity on the part of fragrance companies. He claims to be
unsurprised by this finding, as the core competency of such firms lies in perfumery. Plus,
he suspects they are ambivalent toward any technology that will allow customers to use
less of their products. "There is not much motivation to do this," Shefer observes.

In contrast, he says Salvona has received 15 controlled-release patents and has 80 more
pending. The company employs 17 people to develop and manufacture its systems,
which it sells in 16 countries worldwide. "To develop this technology you need specialized
people," he says. "It's a profession."
In 2003, Salvona licensed a package of 20 controlled-release technology patents to
Imperial Chemical Industries and its National Starch and Alco subsidiaries for use in
fabric care. Since then, the company has come up with a new technology, called
HydroSal, that is aimed primarily at the personal care market but has fabric care
applications as well, Shefer says.

As he describes it, HydroSal starts with 100-nm polymeric spheres that can be infused
with fragrance or other ingredients such as whitening or antibacterial agents. The
nanospheres are then coated with a 5-nm-thick polymeric layer to provide encapsulation.

This polymer system stays intact in water or alcohol-based personal care and cleaning
products and then on the target textile after it is dry. But when the system comes into
contact with water or moisture a second time, the outer film swells and slowly releases
the encapsulated ingredient, Shefer says.

Like Salvona, several traditional specialty chemical companies also consider controlled
release as a core competency. Alco and National Starch, for example, offer techniques of
their own devising even as they continue to develop the Salvona portfolio, according to
Alco's Hetherington. In fact, he says Alco has built upon the Salvona technologies with
what he calls "new art" as part of an effort since last year to expand Alco's delivery
systems development group. This group also markets starch-based encapsulation
technology developed by National Starch, such as dissolvable films that entrap cleaning
ingredients in a dry film format.

International Specialty Products (ISP) is also active in controlled-release technology,
offering its homegrown Microflex microemulsions, based on alkyl pyrrolidone and vinyl
pyrrolidone polymers that deliver hydrophobic actives such as fragrances and biocides.

At the same time, the company has expanded its controlled-release portfolio with the
acquisition of two European encapsulation experts. In 2004, ISP bought Hallcrest, a
British developer of water-soluble polymer-based encapsulants. Then last August, it
purchased the consumer products encapsulation business of the German firm geniaLab
and entered an alliance with geniaLab to develop new encapsulated products for the
fabric care, personal care, and home care markets.

Frank Fusiak, North American director of marketing and business development for ISP's
performance chemicals business, points out that Hallcrest's coacervation technology is
geared to delivering hydrophobic liquid ingredients, whereas geniaLab's JetCutter
technology is aimed at delivering solids.

Both Hallcrest and geniaLab, Fusiak says, made their names in the personal care market.
Since the acquisitions, ISP has been expanding their reach into home and fabric care as
well as industrial and institutional applications. "ISP's success," he says, "comes from its
ability to bring technologies to businesses in which they are not normally found."

Most cleaning product manufacturers depend on third-party technology for their
specialized ingredient-delivery needs. However, a few giants such as Unilever, Henkel,
and Procter & Gamble have their own internal development efforts as well.

For example, P&G has developed specialized techniques to deliver fragrances and
softening agents to fabrics and to enhance the "fragrance experience" of selected
automatic dishwashing products, according to Sharon J. Mitchell, vice president of R&D
for the company's global fabric care business. The company is exploring improved
deposition of additional ingredients as well, she adds.

Mitchell says P&G's Tide with Febreze, Tide Simple Pleasures, and Gain Joyful Expressions
all employ "specific delivery technologies" to enhance fragrance. Although she won't
disclose chemistry specifics, she outlines three steps to efficient fragrance delivery: a
technology that is stable in liquid detergents, a perfume accord tuned to maximize the
efficiency of the delivery technology, and a technology that gets the fragrance to the
fabric in a form that will facilitate release at the appropriate time.

Meanwhile at Henkel, Thomas Müller-Kirschbaum, senior vice president for R&D,
technology, and supply chain for the laundry and home care business, says his
researchers explore targeted delivery of everything from fragrances to enzymes to
bleaches to special fabric care ingredients. And not just in laundry detergents, either.

He points to Henkel's 1999 launch of an automatic dishwasher detergent that used a wax
encapsulate to release a rinse aid when the water temperature reached about 60 oC.
Since then, Henkel has developed a wider palette of technologies to release rinse aids,
water softeners, and shine additives in its autodish products.

FOR LAUNDRY PRODUCTS, one Henkel strategy is what Müller-Kirschbaum calls a
precursor approach, in which a fragrance molecule is linked to an organic molecule for
protection. In the laundering process, the two halves slowly split apart through hydrolysis
or other means, thereby gradually releasing the fragrance.

Precursor technology based on silicic acid esters that bear fragrance molecule
appendages won Henkel's 2004 Research/Technology Invention award. The technology
received its first patents about 10 years ago and is used today to deliver fragrance in
Henkel products worldwide, Müller-Kirschbaum notes. The company since has developed
second-generation molecules, he adds, and today is working on the third generation.

Although Henkel has succeeded in developing commercially viable fragrance delivery
technologies, Müller-Kirschbaum cautions that the company has by no means solved the
problem. "We are in some ways ahead of where we were five years ago," he says, "but I
think the whole industry has a way to go."

				
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posted:2/25/2012
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