Alpine runs first-ever 11-layer blown film line

Düsseldorf, Germany — It's an industry first — an 11-layer blown film line, running in Hall 16/D6 at the booth of Hosokawa Alpine AG.

It's also a first for Hosokawa Alpine, which has displayed lines of up to five layers at a trade show and has manufactured up to nine-layer blown film lines.

“This is the first one right here that we've ever made,” said David Nunes, president of the company's U.S. operation, Hosokawa Alpine American Inc. “It's taking the next step from the nine layers, which is very popular in barrier films. The 11-layer is the idea that you can have the ultimate flexibility. This one came from the lab to here.”

The line running at K 2016 has an 11-layer, fully nested spiral die. That consists of 11 cylinders inside each other, each one precisely machined with channels and spirals for a specific layer of the film, taking the melt from the extruders. The spiral die allows all the extruders to be on the same level.

“The big advantage of a cylinder, it's the strongest shape you can have,” said Jay Ragusa, vice president of engineering at Alpine American. The round shape also has no points where material can accumulate and create gels, hurting the quality of the film, he said.

Nunes said making the spiral dies is a major feat.

“The dimensions of the distribution spirals are critical. To do it right, needs extraordinary technology,” he said.

Hosokawa Alpine is running different variations of materials during the show, depending on the day. Every day, the line is running an EVOH barrier layer in the center, sandwiched between two layers of nylon and two tie layers. That gives the company three layers on each side to change around.

The blown film machinery maker is using barrier materials, tie layers and additives from material from DuPont Co., Kuraray Co. Ltd. and Ube Industries Ltd. Base resins come from ExxonMobil, Dow Chemical Co. and Total SA.

One major feature is the ability to stop the multilayer barrier line each night.

“In the past, companies would let it go 24 hours; to stop it could really be a disaster,” Ragusa said.

“So what we're doing is, every evening after the show, we do purge out the EVOH layer, because it's not a stable material. It has nothing to do with the die; it's the material. So we purge out the EVOH layer. But the nylon, we only do what's called a partial purge. And this has never been done before. We can do it because we are so confident in the way the die is designed; we know it'll work.”

Technicians push a small amount of low density polyethylene through the middle of the nylon layers, leaving nylon against the wall of the die channel. They let the die cool down for the night. At about 5 p.m., it begins heating back up for the next day's production. The LDPE has a lower melting point than the nylon, so it moves through the die, and then nylon is introduced to fill the die channel.

Normally, if you shut down like that, you would have to push out a large amount of nylon and push out other layers to purge the line, Regusa said, because of the dissimilar melting points of the materials.

“I was here yesterday morning when they started, and it was amazing; I couldn't believe it myself,” Ragusa said on Oct. 23. “It goes from starting to production in minutes, not hours.”