Making paper waterproof--and writable

Lab accident at Ecology Coatings leads to method of making paper and other objects that are impervious to water. Images: Ecology's nanospray

Sally Ramsey, founder of Ecology Coatings, jerry-rigged an apparatus in her lab to show a chemical company representative how rapidly one of Ecology's coatings dries when exposed to ultraviolet light.

To avoid making a mess, she put a piece of paper underneath the object she wanted to spray.

When cleaning up, Ramsey exposed the paper to UV light to dry it and make it easier to throw away. On a whim, she checked to see if the coating, which was enhanced with nanoparticles, made the paper impervious to pencils or ink.

News.context

What's new:
Nanotechnology start-up Ecology Coatings says it has developed a spray-on coating that, when properly dried, waterproofs materials--but still allows them to be written on.

Bottom line:
Ecology Coatings says it is talking with chemical companies about using the coating to waterproof a range of products, from address labels to sporting equipment to shoes.

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"For a minute, I was really disappointed. I could write on it all over the place," she said. "Then something clicked."

It turned out that the coating, in combination with the makeshift apparatus, made the paper waterproof without making it waxy, brittle or changing its other characteristics. The original piece of paper has been submerged in water since June 6. It hasn't dissolved and Ramsey's original writing is still on it. She once even took it out of the water, wrote on it some more, and submerged it again.

"It was kind of a 'MacGyver-ish' sort of thing," she said, referring to the 1980s TV series about a scientifically resourceful secret agent. "It turns out also that the paper greatly slows down the growth of mildew."

Although the process is in its infancy and the competition in industrial chemistry is fierce, Akron, Ohio-based Ecology believes the process could lead to shipping labels and tags impervious to the elements, eliminating the need for separate plastic coverings or for the somewhat expensive waterproof paper tags on the market today.

But that's just a start, say Ramsey and Ecology CEO Rich Stromback, who are already talking to chemical giants about how to bring the material to market. They say the process can be used to spray a waterproof, writable surface on sleeping bags, sporting equipment, shoes, volleyball nets and other items.

Potentially, the material could also get incorporated into building materials and compete against materials like Tyvek, the water- and puncture-resistant material that contractors and others gobble up by the square mile.

Ecology's nano-coating

"I've put it on canvas. I've put it on knit material. I've written with a Sharpie, with a pen, a pencil," said Ramsey. "The world is full of things you could put this on."

Plastics, coatings and other industrial materials have emerged as the test beds for the nanotechnology industry. Early nanotech products include stain-resistant pants, golf balls that correct for a hook or a slice, car panels and lighter bike parts .

What makes these nano-enhanced products superior to conventional products, advocates say, is that a sprinkling of atoms can serve to enhance a feature. Fewer atoms mean less weight and fewer alterations to the overall integrity of the final product. And instead of needing wires, a plastic part can conduct electricity by adding nearly invisible carbon nanotubes.

"If you look at the nano success stories to date, they are all in composite materials and coatings," said Matthew Nordan, an analyst at Lux Research.

Although it only has two employees, Ecology has distinguished itself from the pack of nano start-ups to some degree by cutting licensing deals for its quick-drying, ultraviolet light-activated paint substitute with Red Spot, an automotive equipment specialist, and with DuPont.

"There are innumerable nanotechnology companies that would kill to get the kind of validation these guys have gotten in a very short time," Nordan said. Still, the company faces major economic and technical challenges in moving its products from the lab to actual production, he warned.

How it works
What is the secret sauce behind the company's waterproof paper? Ecology is somewhat vague on that. The coating is a version of the company's UV-curable material. The lab apparatus affects the material in such as way that the coating actually permeates the paper, rather than just forming a layer on top, like a typical coating.

"The apparatus sort of hurls it into the paper," said Ramsey. "It gives the drops some interesting momentum."

Patents on the chemicals and the process are currently being sought. Nonetheless, Stromback added that the process will likely scale to mass production and not require unusual machinery.

"There's nothing that we see that is prohibitive in terms of the process," he said. "The technique can easily be put into place on existing paper production lines."

Stromback added that industrial users may be able to incorporate the material into other products within 18 months to two years. Ecology doesn't engage in manufacturing on its own at the moment, but licenses ideas to established chemical concerns.

Ideally, waterproof paper and labels produced by this process will be far cheaper than today's counterparts. Manufacturers today produce waterproof labels, but it requires embedding polypropylene fibers in paper. The process is expensive but also makes the paper waxy and tough. (Those rubbery parking tickets given out by some cities are made of such material.) Ecology claims its process will cost about 500 times less because ordinary paper can be used.

Additionally, because paper manufacturers coat the paper they produce today, their chemical budget will stay roughly flat because they can substitute the new coating for the old one.

Although the coating prevents mildew growth, Ramsey asserted that the material does not likely pose a health hazard. No toxic materials or fungicides were added. Mildew inhibition may come from the fact that the paper can't get moist.

"This was a very happy accident," Ramsey said.

 

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