Seven-Layer Line Keys Processor's Expansion
Addition of Davis-Standard blown film line allows Findland’s Rani-Plast to expand customer base while offering greater flexibility.
In the two years since installing a seven-layer Davis-Standard blown film line,
Rani Plast of Finland has expanded its family-run business by optimizing production and introducing new products. At the time of installation, this was the largest seven-layer blown film line Davis-Standard had ever built.
“Before this line, we lacked capacity and were limited to film widths of 18 meters. Being able to run expanded widths has given us access to new distributors and customers,” explains Mikael Ahlback, Group CEO of Rani Plast. “It has also given us greater flexibility to react on immediate demands from customers, shortening lead times. We’re able to offer new products such as EVOH-based barrier films that will be available the next agricultural season. This product will be sold as an underlay film as well as a conventional silage film to help customers make better silage than before.”
Ahlback notes that the demand for silage films, one of Rani Plast’s largest markets, has risen due to the increased size of farming operations. The seven-layer structure has helped Rani Plast optimize mechanical film properties for this film in a manner not previously possible. In addition to silage, Rani Plast uses the seven-layer line for making wider films for covering peat and turf.
The line’s design is a reflection of careful planning and customized engineering. A 2.3-meter, seven-layer Centrex IBC die has been an integral part of performance. This die supports enhanced film quality while providing Rani Plast with versatility for their diverse portfolio. This includes the capacity to process high-quality films with optimized coextrusion ratios for thicker skin layers and low-percentage core layers for barrier-based structures, as well as non-barrier structures using a variety of polymer blends. The die and tower are capable of producing a bubble up to 23 meters unfolded at high-output rates with a dual-lip,automatic profile control air ring.
The line’s seven Davis-Standard MAC extruders are fitted with DSB feedscrews for homogenous mixing and low-temperature melt streams, essential to film quality and the
production of large width films. “A big part of our success was the support of Davis-Standard during installation, the initial start-up period and optimization of the line” says Ulf Sandvik, project manager at Rani Plast.
Just like selecting the extruder size and drive combination, the L/D should be carefully evaluated.
All things being equal, PET will outperform PBT mechanically and thermally. But the processor must dry the material properly and must understand the importance of mold temperature in achieving a degree of crystallinity that allows the natural advantages of the polymer to be realized.
Newer specialty slip masterbatches go beyond traditional capabilities to provide greater thermal stability, reliability, and ability to hold COF steady during laminating.