Less (Thinner) Film, More Uses

How thin is thin? Well, it depends who you talk to. Actually, if what you're talking about is film, it depends on the process and the application.

Eric Bartholomay, product development manager at Toray Plastics (Americas), North Kingston, RI (toraytpa.com), says thin films historically were defined as 1 mil and below. While his company makes films to 2 mils, which they call thin, the marketplace, he notes, typically calls thin films ½ mil and thinner. Markets such as magnetic tape for cassettes and thermal transfer ribbon require even thinner film.

John Fenn Jr., president of Fennagain, West Hills, CA, works in the area of vacuum deposition, so for him, thin films may be coatings of less than 1 micron. “Actually, we vacuum-deposition people were the original creators of nanotechnology. We've been putting down films for a long time in the thickness range of less than 100 angstroms.”

Says Bartholomay, “Any market that is a unit area, including packaging, film-to-board laminations, and film-to-film laminations, inherently has a desire to go thinner, because you get better yield and presumably better cost.”

Thinner film also is desirable, he adds, in decorative applications such as wall coverings.

When it comes to processing, going thinner can be both an advantage and a challenge to converters, Bartholomay points out. “For example, if rigidity is a problem, thinner is an advantage because the product will be less rigid. On the other hand, films can tend to wrinkle as you get thinner. Also, going thinner works better for some plastics than for others, since mechanical and thermal properties may come into play more as you go thinner.” That, too, can be a blessing, Bartholomay says, giving the example that, since polyester is denser than PP, it is more expensive on a pound-for-pound basis with the same thickness. “But the mechanical and thermal properties of polyester are generally better than propylene, so often you can use thinner polyester.”

Fenn says people are beginning to use thin film deposition sputtering technologies for manufacturing medical sensors. This is one of the applications that presents a big challenge to converters, he says. “We have to come up with a way of producing more defect-free substrates. Film manufacturers have to step up and invest in cleaner operations, which is a hard thing because the market may not be there to justify that expenditure. Specialty roll coating will never be the size of food packaging or insulation.”

Liz Josephson, manager of system sales at Applied Films, Longmont, CO (appliedfilms.com), agrees “clean” processing is crucial to new applications for thin films. “It's a chicken-and-egg thing. Film processors say, ‘If we have enough volume, we'll get the equipment.’ But until they get the volume, they can't afford the equipment. On the sputtering side, it's a very big initial cost.”

Both Josephson and Fenn see flexible all-plastic displays in the future. “Flexible displays are a hot topic,” says Josephson. “It's not happening tomorrow but down the line. They're trying to take the glass out of [displays] completely, but that's only going to happen in specific applications.”

A developing market for thin film deposition, Josephson adds, is new packaging applications. “It's huge. As more and more countries bring in packaged goods instead of selling fresh goods, for example, that growth will continue. It's exploding in China and starting to come up in South America.”

In thin film deposition equipment, Josephson finds customers asking for more processing in the chamber. “They want to eliminate some process from somewhere else in the line and enhance the end product. This might mean cleaning or post-treating in the chamber.”

Bartholomay's customers want thin films to be more functional. “It could be adding barrier, or allowing heat-sealability, or allowing it to be used as a resealable lidding stock. We have to innovate to bring economies to our customers. When you do something in making the film, you can usually do it less expensively than if you do it afterward.”

Bartholomay expects films to get thinner in the future, especially in packaging markets.

So how thin is thin? A more important question might be, “How far can thin films go?” Pretty far, say these experts.

Restrictions of time and space limit the number of companies, products, and trends that we can discuss in these reports. For additional information, see PFFC's features and departments each month, consult the June Buyers Guide, and check pffc-online.com.

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