Kalwall

The Light Stuff
Cabot process allows commercial use of 'aerogels'

The Boston Globe
Tuesday, December 27, 2002
By Peter J. Howe, Globe Staff

Now, Boston-based Cabot Corp. is rolling out the first major commercial application of the silicon-based material: window and skylight panels that use aerogels for heat and sound insulation while allowing light to pass through.

Through a partnership with Kalwall Corp., a New Hampshire maker of fiberglass window units, Cabot this month completed the first installation of what it is calling Nanogel, replacing a Manchester, N.H. motel swimming pool roof. Besides construction, scientists at Cabot, a $1.7 billion-a-year maker of specialty chemicals such as carbon black, are looking into ways to use the superlight insulating material in automobiles and even clothing items like parkas and mittens.

Aerogels are described by scientists as the lightest form of solid matter that exists, the residue left when silicon dioxide compounds are turned into a kind of Jello and all of the water is removed. A cubic foot of the compound can weigh less than seven pounds, made up of particles ranging from 1/20th to 1/6th of an inch in diameter.

While large commercial markets have been long in coming, aerogels have been used in NASA projects, such as Mars exploration vehicles and a space probe capturing comet-tail dust.

A Marlborough company called Aspen Aerogels has developed very high-priced insulated clothing and blankets using aerogels aimed at markets such as Antarctic explorers and the military, and other products for specialized uses in aerospace, cryogenics, and high-tech manufacturing.

Aspen marketing director Chris Blair said the company plans late next year to roll out a line of lightweight winter sports outerwear through a partnership with Burton Snowboards of Burlington, Vt.

However, the staggering cost and complexity of producing even small quantities of aerogels has prevented any kind of big commercial market from developing.

Cabot says its breakthrough has been to develop a way to make aerogels in a bulk continuous process, at a new factory in Frankfurt, through a so-called silation process that does not require the kinds of pressurized chambers of extreme heat used in earlier manufacturing approaches. The Frankfurt factory can be ramped up to produce millions of cubic feet of the material annually if demand develops, Cabot spokeswomen Ethel Shepard said.

While specialized insulated windows could become a substantial market globally, Cabot has not made any predictions about potential sales.

Mark Kalin, a top official with the Boston Society of Architects and president of Kalin Associates, a Newton architectural consulting firm that specializes in evaluating materials for building specifications, said the Nanogel products appear promising. At least two local architects, Kalin said, are investigating using them in projects.

Kalin said the Nanogel products may help builders comply with toughened energy conservation rules. In particular, Kalin said, the difficulty of insulating aluminum-framed windows has led many builders to turn to fiberglass and wooden window units for "high-performance" buildings such as offices and schools.

"Maybe this is an area where the product might find a welcome home," Kalin said.

Sidney Perkowitz, an Emory University professor who wrote extensively about aerogels in his 2000 book "Universal Foam: From Cappuccino to the Cosmos," said that it is "very exciting" to see Cabot beginning to commercialize aerogels.

"It's an amazing material. It has all kinds of wonderful properties," Perkowitz said, adding that using it as heat and sound insulation in buildings "is a fantastic idea. It seems to me like the potential for it is very, very good."

Insulation "is not the sexiest application, but it's a huge market, and when it's out there people are going to find uses that aren't even apparent to us now."

Kalwall, which was founded in 1955, has installed hundreds of translucent wall and skylight systems, including projects at the three New York area airports, the Manchester airport, several school gymnasiums and pools, and specialized installations for museums.

Said Bruce Keller, Kalwall's marketing vice president: "Nanogel is a giant step in technology for us. It's the magic insulation material."

Earlier this month, crews completed replacement of a 30-year-old Kalwall roof over the pool at the 104-room Comfort Inn in Manchester with a version containing the Nanogel insulation.

"It's very attractive," said Fred Bailey, owner of the motel. "It lets a lot of light through, and the insulation value is even more astounding when you consider that it's also translucent." NASA scientists have coined the phrase "frozen smoke" to describe what aerogels look like.

While Kalwall executives were immediately intrigued by the possibilities for using the material in their window and skylight units, Keller said, it took several months to ensure it would work.

"You have to consider every regulatory agency there is," Keller said, and address issues such as flammability and mildew in the windows and protection for manufacturing employees against breathing in harmful amounts of the dust.

A Kalwall panel 2-3/4 inches thick insulated with the Nanogel material can have the same "R-20" insulation value as a house or building wall, while allowing about 20 percent of the outside daylight to flow through. Different versions offer more daylight with less insulation, and the sound-proofing capabilities of the material - particularly for low, rumbly noises like truck and airplane engines - make it attractive for airport and commercial buildings, Keller said.

James N. Litrun, the Nanogel sales manger for Cabot, said the company expects to work through partnerships to find commercial product applications for the substance.

"We're scientists, we're chemists - we don't know the construction industry," Litrun said, explaining the decision to work with Kalwall.

With 4,200 employees worldwide, Cabot makes a range of products such as fumed silica and carbon black that are used in thousands of consumer and commercial products, but are virtually unknown to most people who are not industrial chemists. In the quarter that ended Sept. 30, Cabot posted a net income of $28 million on sales of $440 million.

Cabot has bought or licenses more than 100 patents covering the Nanogel technology, including intellectual property from German chemical giant Hoechst. One of its innovations has been creating a way to make the aerogel material "hydrophobic," or water resistant, so that the window units will not absorb vapor or moisture.

Chemist Samuel S. Kistler at the College of the Pacific in California is credited with creating the first aerogel, in 1931, using alcohol on a gel put under very high heat and pressure to force out the water. Last May, the Guinness Book of World Records awarded a "world's lightest solid" prize to Steven Jones of NASA's Jet Propulsion Laboratory in Pasadena, Calif., for a version of an aerogel weighing just 3 milligrams per cubic centimeter, or 1/300th the weight of water.

"To make aerogel (entirely) clear is the challenge," said David Noever, a top NASA aerogel researcher at the Marshall Space Flight Center in Alabama. "Once you make it clear, it becomes a whole new product and it opens up a whole new world of applications."

Aerogel technology
Invented in 1931, "aerogels" - a super-light silicon compounds that can be up to 97 percent air by volume - are finally being produced for commercial use by Boston chemicals giant Cabot Corp. Cabot and New Hampshire-based Kalwall Corp. have introduced insulated skylight and window panels using a Cabot-produced aerogel compound.

Production - Cabot's breakthrough has been finding a way to produce aerogels in volume, using patented technology, at a factory in Germany. Previously aerogels could only be made in small.

Energy conservation - Carefully pouring aerogels into translucent wall panels can give them a thermal insulating capacity equal to 10 to 20 window panes, or the same as an insulated wall rated R-20. The aerogels also act as sound insulators. The translucent nature of aerogels could make them popular for use in skylights or school and commercial buildings where owners want to reduce use of electric lighting.

Sources: Jet Propulsion Laboratory, nasa.gov

Aerogel is produced differently for several other applications, particularly as a lightweight, yet strong, component.

A block of aerogel as large as a human may weight less than a pound yet support the weight of a subcompact car.

Employees of the Comfort Inn in Manchester, N.H., regarding the motel's new roof, the panels of which were make with an "aerogel" called Nanogel.
It's been hailed as the world's lightest solid, and a near-magic material. Yet more than 70 years after chemists first discovered the extraordinary form of matter called "aerogels," it's been used almost exclusively by space researchers and in niche markets.