Machinery makers are being challenged to address the increasing demands of cast stretch film — getting film thinner and thinner while improving strength and flexibility. New technologies introduced at K 2013 have improved even more.
In general, cast film markets worldwide are healthy, and the cast stretch film market is particularly strong and growing. It's solid in North America, growing at nearly 3 percent annually, while growth is even higher in many emerging economies around the world. Despite the slowdown that's taken place in many of those economies, as well as in many economically mature regions, globalization of manufacturing means that a lot of shipping is going on.
These days much of that shipping takes the form of pallets stacked with cartons or other shapes of packaging traveling by ship, train and truck. Shippers believe all that merchandise should arrive at its destination perfectly intact. Yet recent studies estimate that annual losses due to products damaged in handling and transport cost shippers about $2.6 billion.
That is precisely the problem that rolls of stretch film have been relieving for decades. Everyone involved with goods transport for any length of time has seen the percentage of pallets securely wrapped in transparent film steadily increase. It is still increasing, as is the strength of the film — even as it has gotten thinner and, as a result, more sustainable and economical.
Naturally, it took a parade of significant materials, machinery and processing innovations to make stretch film stronger, thinner, lighter and more sustainable and economical. And just as naturally, with stretch film usage rising, along with market demands for improved performance and lower cost, the development of technology innovations is holding its fast pace.
Clear evidence of that is the variety of technological innovations coming from machine line makers — often in concert with resin suppliers — that are now offering stretch film processors options and tools to improve their products that, as recently as 10 years ago, were unthinkable. Examples: A leading supplier of cast stretch film lines is moving what was a major off-line process to in-line; another longtime maker of cast film lines has developed a totally new, stretch-film-specific winder to spearhead a major push into that market.
Steve Post, VP of cast film at extrusion and converting system supplier Davis-Standard LLC, Pawcatuck, Conn., says about 80 percent of the total cast film machine market consists of stretch wrap, hygiene film (diaper back sheets, hospital gowns and bed sheets, etc.) and cast polypropylene. Stretch is by far the biggest part, hygiene film is growing and so is cast PP, TPU film, PE film, though almost all in Asia.
Suppliers of stretch film in North America are bullish about a market that's growing at close to a 3 percent annual clip, says Post. And, he points out, it's growing from a relatively large base. Suppliers feel resin prices will drop as natural gas supplies increase. Shipping film made in the U.S. to Europe is well within the realm of possibility.
Post says one familiar trend is continuing in the stretch film market — downgauging. A few decades ago film that was 25 to 30 microns, or around 1 mil thick, was considered thin. Post says his company's lines are now making stretch film as thin as 6 microns in the conventional process and the pre-stretch process, where the film is stretched in-line to make it stiffer and thinner. That's thin for sure, but the real breakthrough here is that the pre-stretching is being done in-line, on a station just before the winder.
Pre-stretch began in Europe about 10 years ago and began to take off about three years ago in North America, where currently it's growing at a rate of more than 15 percent a year. But as Post points out, no one is doing pre-stretching in-line now. It is being done off-line using rewinders. Aiming to change that, Davis-Standard launched its new dsX s-tretch pre-stretch cast film extrusion line at the K 2013 show in Düsseldorf, Germany, and made pre-stretch film in-line on a working line at its German facility.