Automation, versatility, more efficient use of resin and the promise of improved recyclability were among the highlighted attributes of stretch film lines that took the floor at K 2019.
Brückner Maschinenbau spotlighted its line’s ability to produce film using less raw material, along with a number of other new technologies, while SML Maschinengesellschaft mbH touted the flexibility of its upgraded PowerCast XL stretch film line.
Brückner has developed a film stretching line capable of producing both biaxially oriented (BO) PE and PP films; it is available in two sizes.
BOPE film has better mechanical and optical properties than conventional PE film, allowing it to be manufactured with 30 to 50 percent less thickness. BOPE film also offers excellent clarity, and is suitable for food contact and easily recycled.
“Thinner films mean less raw material and less energy is involved,” said Sebastian Lange, VP of Brueckner Group USA’s film division. “This would also reduce the carbon footprint and, in the end, it’s more sustainable, but this is just one aspect of many when it comes to the benefits of BOPE.”
In addition to its advantages over standard PE film, BOPE is superior to BOPP film in some ways — for example, the sealing performance and seal integrity of BOPE film are better than BOPP film. BOPE film also is puncture-resistant and tears in a linear fashion, making it useful for easy-open packaging, according to the company.
The new line comes in two sizes. One has a working width of 21.6 feet and an output of about 3 tons per hour, and the other a working width of 28.5 feet and an output of 5.5 tons per hour. Both can produce five-layer film. While designed primarily for BOPE production, they also can be used for producing BOPP film.
The technology is intended to meet increasing customer demand for BOPE film, which is becoming more attractive as the costs associated with producing the film fall and demand for recyclability rises.
Brückner received several requests for quotes on the new lines at K 2019, said Helmut Huber, COO for sales and project management.
“It’s really, I would say, a demand now from the market,” Huber said.
BOPE film has been available for about a decade, but initially only one company in the world supplied the material, and it was expensive, he said. Today, there are several producers and the cost has dropped by approximately one-half.
In addition, governments, especially in European markets, are demanding that more material be recycled.
“Now, what the industry is looking for is recyclability,” Huber said. “In the former time, nobody looked about that.”
Today, LLDPE resin is used to produce BOPE film for use as a sealable laminating film or for packaging for frozen food or cookies.
In the future, HDPE resins tailored for BOPE will be available, offering new opportunities, Lange said.
To obtain the necessary mechanical and optical properties, packaging often consists of different materials, making recycling difficult or impossible.
“In the future, what they are looking for is there can be three layers, but out of one family — mono-material structures,” Huber said.
Eventually, Brückner’s goal is to supply machinery that would allow film producers and packaging converters to produce mono-material film and packaging materials that use only PE instead of producing multilayer films from multiple materials. This would help manufacturers create mono-material films that are easier to recycle and that have superior mechanical and aesthetic properties.
To that end, the company is developing a method of producing a BO HDPE film that would be stiff and resist shrinkage, making it suited for the base layer of a multilayer film. That development could fuel the move toward mono-material packaging, Lange said.
The still-under-development systems would produce a PE film strong enough to satisfy most or all packaging applications — without requiring lamination to other materials.
“The trials are running on our pilot line at our headquarters in Siegsdorf [Germany], and we expect to come up with a full PE structure by mid-2020,” Lange said.
In some regions, such as Europe, recyclers can handle multilayer films that include both PE and PP because both materials are polyolefins. But in the U.S. in particular, there are few streams for those combined plastics. Other combinations of polymers lack a recycling market anywhere in the world.
“The most desired or the best level then would be a true mono-material stream, which would be BOPE only,” Lange said. “Especially when we speak about the recycling system in the United States, pure BOPE packaging would be appreciated as those recycling streams exist already.”
Brückner also has developed a new inline coater for its BOPP lines, as well as its new BOPP/BOPE line.
It is installed in the line upstream of the transversal direction orienter, and it makes possible the production of functional layers that are extremely thin — within the nano-range. The coating is a primer that prepares the film for a separate metallization process, Lange said. For example, once they have applied the initial coating, manufacturers can apply an aluminum oxide layer to serve as an oxygen and vapor barrier; the aluminum oxide can be thin enough that it won’t interfere with recycling.
Also during K 2019, the company introduced Brückner One, a digital communications and information storage system to assist with maintenance and repairs on Brückner’s BO film lines.
The system maximizes the availability of stretch-film lines and minimizes maintenance and downtime costs, the company said. All data is stored securely, and the system consists of modules covering service requests, spare parts inquiries, communication and line documentation.
The Brückner One Support module allows users to submit a service request and track the status of that request online. Communication between a Brückner service center and the users takes place within the support module. Users can access the information through a computer or an app for mobile devices.
The Brückner One Parts module allows a customer to rapidly identify and order spare parts. Needed parts are determined using an online catalog that includes drawings and descriptions or part numbers, and a request for parts can be forwarded digitally to Brückner.
The Brückner One Com module provides the most flexible interaction between the Brückner service team and customers. The module allows communication using via a chat feature, video conferences and whiteboards. It also supports the use of smart glasses or other video devices.
The Brückner One Docu module provides paperless and simple-to-use online technical documentation. Users can retrieve relevant information digitally when servicing the production line. The module also makes use of video clips to demonstrate service procedures when necessary.
The system consists of hardware and software, including a firewall, for security while transferring data to Brückner.
SML’s upgraded PowerCast XL line can produce rolls with widths of 1.3, 1.5, 1.6 and 2.5 feet with no increase in trim ratio, and is designed for all standard stretch films, including low-density PE and polypropylenes for stretch film. It is intended for customers that require high-volume production but also need flexibility in the film thicknesses and roll widths they produce. Its versatility is a key to meeting market requirements, according to the company.
The PowerCast XL features a net film width of about 14.8 feet. It can produce films with seven, nine, 11, 13 or 55 layers. At K 2019, SML displayed a line that included eight extruders for producing 13-layer film. It featured a 5.2-foot-diameter, 16.4-foot-wide chill roll and a double-turret winder — the W4000 4SW 2T — with four shafts per turret. It weighed 169 tons and took a team of SML engineers only 20 days to set up, which the company called record-breaking.
The upgraded line includes SML’s newly introduced “hands-free” technology for the extrusion die, which makes product changes fast and straightforward, the company said. Less labor is required, waste is reduced, and overall line efficiency is increased. The technology involves software and a Cloeren Reflex die; the die on the machine on display was 17.5 feet long.
“This die can make the major corrections to start the line up when you do a big product change, and then on top of that, it can make the minor corrections, as well,” said Mark Jones, director of support services in North America for SML. “The big advantage to that is that you no longer need a skilled operator to set up the die, and skilled operators are very difficult to find. It’s a skill that takes quite a long time to acquire, and adjusting the die manually takes four or five times longer than the software, and whilst you’re adjusting manually, you’re wasting film.”
The new “hands-free” die adjustment eliminates the need for manual adjustments during product changes. The changeover process can take 30 to 45 minutes using a conventional system. Using SML’s software to regulate the die, operators of machines equipped with the hands-free Reflex die can complete a changeover in only 10 minutes.
Another innovation is SML’s automatic mapping of die bolts, which minimizes labor and the production of waste. With conventional equipment, an operator needs to manually map the die at every product change to ensure good regulation of the thickness. However, new SML software constantly and automatically regulates the expansion and contraction of the die bolts relative to the film’s position. The thickness-measuring unit recognizes the position of the bolt and automatically adjusts the mapping, the company said.
The PowerCast XL line, like all SML stretch film lines, measures the temperature of the extruded film directly on the chill roll. This gives manufacturers the ability to predict the quality of the film based on its elongation during production. An operator then knows immediately if any adjustments are necessary to obtain the right properties.
Bruce Geiselman, senior staff reporter
Brueckner Group USA Inc.,
Portsmouth, N.H., 603-929-3900,
SML North America Service Inc.,
Gloucester, Mass., 978-281-0560,