A New Spin on Dry-Cleaning
Dry-cleaning is one of the great misnomers of modern life.
It isn’t a dry process: Liquid solvents such as perchloroethylene and petroleum are used as substitutes for water. Nor is it clean, as far as the environment is concerned: The Environmental Protection Agency identifies “perc” as a cancer-causing agent, and the petroleum used to scrub threads releases smog-producing compounds and is flammable at high temperatures.
Now dry-cleaners are poised to wash their hands of perc, petroleum and other harmful chemicals in favor of a new process that relies on a clean, reusable solvent: liquid carbon dioxide. For the nation’s 30,000 dry-cleaning shops, their landlords and many of their customers, the new technology promises nothing less than a revolution.
“Carbon dioxide is a benign, inert, inexhaustible resource,” said Jack Alquist, who owns three dry-cleaning stores in Northern California and is chairman of the International Fabricare Institute, the industry’s major trade group. “If the process does what the scientific papers say it will, it should be gentler to fabrics and have better cleaning capabilities.”
Liquid carbon dioxide has long been seen as a promising alternative to current dry-cleaning solvents. But scientists were stumped on how to design a detergent that would clean effectively in a liquid CO2 solution.
Researchers at Hughes Environmental Systems in El Segundo and at the University of North Carolina at Chapel Hill independently--and quite accidentally--hit upon key methods that make dry-cleaning with liquid carbon dioxide feasible. Those innovations have spawned a pair of companies that are commercializing the technology and plan to make it available to consumers as early as the first quarter of next year.
Dry-cleaners typically wash wool, silk and other garments that can be damaged by water. The clothes are submerged in perc or petroleum and mixed with specially formulated detergents that pull dirt particles away from cloth. Then the clothes must be heated at high temperatures so the solvents will evaporate and the clothes will dry. The dirt particles are disposed of with the used solvent.
Washing with liquid carbon dioxide is a quicker and cleaner process. The CO2, which is a gas at room temperature, must be liquefied in high-pressure storage containers and washing machines. Liquefied CO2 is commonly delivered to restaurants and used to carbonate soda, and dry-cleaners would be able to buy it from the same sources.
The key discovery came when chemists created a detergent that, when added to liquid carbon dioxide, breaks up into spheres called micelles that attract CO2 on the outside and water on the inside. Dirt and stains that are water-soluble--such as grass stains--are drawn away from clothes and into the micelles. The detergent itself does not adhere to the clothing.
When the clothes are removed from the high-pressure washer, the carbon dioxide reverts to its gaseous state; it can be captured and reconverted into liquid for use in another cycle. The garments dry as soon as the liquid evaporates from the cloth. The dirt particles trapped in the micelles don’t evaporate, and they are easily collected as a residue for disposal.
At Hughes, chemists had been looking for an environmentally friendly solvent to clean metals, circuit boards and other aerospace electronics hardware. In 1990, they commercialized a cleaning method that uses supercritical carbon dioxide, which is still a gas but has the density of a fluid because of its high pressure. Four years later, they adapted the process for dry-cleaning.
“We said, since this can remove organics and dirt from hardware, we can’t see any reason why it can’t work for clothing,” said Sid Chao, president of Hughes Environmental Systems.
The Hughes system uses liquid CO2 and special washing machines that move clothes around with jets instead of moving parts, which make it more difficult to maintain high pressure inside the machine, Chao said.
Meanwhile, chemists at the University of North Carolina were studying ways of manufacturing plastics without using organic solvents that pollute the air, such as chlorofluorocarbons, or CFCs. By 1992, they had made some kinds of plastics with carbon dioxide instead of CFCs.
Joseph DeSimone, a chemistry professor at UNC, realized that the method could also be used to make detergents for use with liquid carbon dioxide, and it took his group a few more years to figure out exactly how to do it.
Last year, DeSimone raised $5 million in venture capital and started Micell Technologies to commercialize the technology. The Raleigh, N.C., firm will sell the MiCare Garment Cleaning Fluid System--which includes liquid carbon dioxide, machines manufactured by American Dryer Corp., detergent and technical support--starting early next year. Micell Technologies President Brad Lienhart expects to have 100 customers by the end of 1998 and 500 by the end of 1999.
Hughes Environmental Systems decided to license its dry-cleaning system, DryWash, to Global Technologies of El Segundo. Global Technologies, in turn, has struck licensing deals with seven manufacturers of dry-cleaning machinery, five chemical makers who will produce detergent, and another firm that will make a specialized formula of liquid CO2 with additives to help the cleaning process, said company President Jack Belluscio. The system will be available to dry-cleaners in the second half of 1998, and Belluscio said he expects to capture 10% of the dry-cleaning market by 2000.
“We’re expecting to revive the industry,” said Belluscio, a former Citibank investment banker. “Real estate centers are not putting dry-cleaners in because they’re worried about the environmental impact, and consumers are shying away too.”
Environmental regulators have been exploring a technology known as “wet cleaning,” which uses water in carefully controlled, computerized machines to protect fragile fabrics such as silk. But some fabrics, such as wool, are prone to shrinkage or damage in water, and the wet-cleaning process is more time-consuming than normal dry-cleaning. But those drawbacks don’t plague liquid CO2 systems.
“Carbon dioxide is nontoxic, it doesn’t impact anybody’s health, and it’s a very benign solvent,” said Ranji George, program supervisor in technology advancement for the South Coast Air Quality Management District. “In my personal opinion, it has great potential, and we look forward to its commercialization.”
However, Global Technologies and Micell may have trouble convincing dry-cleaners to spring for the comparatively high cost of the new machines. A state-of-the-art machine that uses perc costs between $65,000 and $80,000, and machines that use petroleum are 20% more than that.
Micell says the first machines for liquid carbon dioxide will cost $125,000, and Global Technologies--although it won’t give a price--also says the machines will initially be more expensive. In an industry where a majority of the businesses are family-owned and gross an average of less than $200,000 in sales a year, such capital investment is a significant hurdle.
Still, the companies say the new machines will pay for themselves. It takes about an hour to process a load of clothes using perc or petroleum, including 30 to 40 minutes for a high-energy drying cycle that isn’t necessary when washing with liquid CO2. Dry-cleaners could therefore process two to three times as many loads with one machine. Pollution-prevention grants in some states might also help cleaners cover the cost of a new machine.
Another slight drawback is that the CO2 process shrinks acetate fibers somewhat, Alquist said. But that is outweighed by the fact that it is gentler on dyes and prevents clothes from fading, he said. Plus, since there’s no heat in the drying cycle, garments should last longer, he said.
Indeed, a Micell demonstration in June at Clean 97, the industry’s biannual trade show, showed that the liquid CO2 method works at least as well or better than perc on berry, coffee and other stains, Alquist said. Hundreds of dry-cleaners pressed both companies for information about the new technology and when it would be available.
Chris Edwards, president of Cleaner World, a chain of 55 dry-cleaning stores based in High Point, N.C., said he is very interested in testing the liquid CO2 cleaners. A pollution-prevention grant from the state of North Carolina might help him cover the cost of a new machine, he said.
Dry-cleaners in Los Angeles said the higher cost of new liquid CO2 machines would not necessarily be prohibitive if the process works as promised. Increasingly stringent federal regulations are forcing them to consider expensive upgrades of perc-based machines anyway, they said.
Vivian Bowers-Cowan, president of Bowers & Sons Cleaners in central Los Angeles, said her family has been cleaning clothes with perc for three generations without suffering any adverse health or environmental effects.
But EPA and AQMD regulations have boosted her paperwork by one-third, and increases of about $1 per gallon in the price of perc since last year have made her more eager to find an alternative. Liquid carbon dioxide would also be convenient, because without a drying cycle, buttons, bows and other clothing embellishments would be far less prone to damage, she said.
Allen Gershenson, vice president of sales for Sterling Cleaners, which has two locations in the Westwood area, said that he was intrigued by the Clean 97 demo but that more tests would be needed to convince him the technology can live up to its promise.
“We’re all looking for something that’s better for the environment, and this is positive from the standpoint of eliminating chemicals,” Gershenson said. “It’s potentially a real viable solution.”
Karen Kaplan covers technology, telecommunications and aerospace. She can be reached at karen.kaplan@latimes.com
(BEGIN TEXT OF INFOBOX / INFOGRAPHIC)
A Different Solution
Traditional dry cleaning methods use harmful and polluting solvents like perchloroethylene and petroleum. An alternative system using liquid carbon dioxide promises to clean up dry cleaning because it is reusable, produces little waste, and is as safe as the air we breathe, or at least exhale. Here’s how it works:
Step 1:
Liquid CO2, clothes, and specially formulated detergent are put into machine.
*
Step 2:
Machine is kept at high pressure to keep the CO2 liquefied. Clothes and detergent are stirred in the CO2 and dirt is drawn into the interior of detergent particles, called micelles.
*
Step 3:
At the end of the cycle, pressure is released and CO2 reverts to gas, which is collected for reuse. Clothes dry immediately as CO2 evaporates. Remaining detergent and dirt particles that are left behind are collected for disposal.
Researched by KAREN KAPLAN/Los Angeles Times
