"We were successful as converters and wanted to take the next step with our company," says Sławomir Bielawski. In 1996, he had founded Duet SP. Z o.o. together with his brother Edward Bielawski. Since 2000, the Polish company has been producing film packaging for food, money, computer parts and other goods that are usually vacuum-packed. "It wouldn't have helped us move forward if we had just put other bag machines into production," says Sławomir Bielawski. "We talked to many potential customers who only wanted to work with us if we also produced film ourselves." That's why the brothers took a big step: Duet was to go from converter to manufacturer. No sooner said than done.
Duet SP. Z o.o.
Barrier film as targeted product
The starting point for the brothers' ambitious project was the search for the right equipment. "It was clear to us from the very beginning that we wanted to produce thermoformable barrier film," reports Bielawski. After all, Duet had already gained a lot of experience in processing this type of film. The barrier film had to be highly transparent, easy to form and have good mechanical properties. "We knew from the market that 'water quenching', i.e. the rapid cooling of the film by water, was the best method for our film property requirements," explains Bielawski. Duet compared different technologies and chose a 9-layer EVO Aqua Cool blown film line from Reifenhäuser. "Because it is our first line, the selection process was not easy. However, we had a good relationship with our contacts at Reifenhäuser right from the start. That was just as important to us as good technology," says Bielawski. "We were convinced by the overall package of trust in Reifenhäuser as one of the leading manufacturers of film extrusion lines and high-performance technology that delivers the film quality we need."
Edward Bielawski, DUET Vice President of the Management Board, Maximilian Herchenbach, Senior Product Manager Aqua Cool at Reifenhäuser, and Sławomir Bielawski, DUET Chairman of the Board (from left to right)
Cooling due to contact with water
The heart of the Reifenhäuser line is the EVO Ultra Quench water cooling and vacuum calibration chamber. In it, a great deal of heat is extracted from the bubble in a short time by water contact. The vacuum in the cooling chamber provides effective cooling, the necessary stability and ensures that the blow tube leaves the cooling chamber almost dry. The water shock cools down the film, thus inhibiting or even stopping crystallization," explains Max Herchenbach, Senior Product Manager Aqua Cool at Reifenhäuser. "As a result, the film produced remains highly transparent and glossy, is easy to form and has high puncture resistance."
Properties of Aqua Cool Film
Blown film production from zero to hundred
In 2022, the time had come: Duet started up the EVO Aqua Cool blown film line and has been producing 9-layer barrier films ever since. "That was a start from zero to a hundred for us," recalls Bielawski. "We had no experience in film production, but we didn't want to gain experience with fewer layers first, because we already knew that we needed nine layers for the properties we were aiming for. Our contacts at Reifenhäuser supported us on our journey."
Highest transparency due to fast coolin
"Our water-cooled barrier film is particularly well suited to customers who require a somewhat thicker film but still place great value on transparency," emphasizes Bielawski. This is because the thicker the film, the more clearly the advantages created by the rapid cooling of the film become apparent: "With very thin standard films of 65 µm, for example, the difference in transparency between cast films, air-cooled and water-cooled blown films is not that high, but when we produce films with a thickness of 140 µm, for example, you can clearly see the difference," explains Bielawski. "With water cooling, transparency is maintained even at greater film thicknesses and our customers can present their product in a visually high-quality manner."
The line has been running reliably 24/7 since startup with an output of 500 kg/h. Duet sells the film both as parent rolls and as converted webs for thermoformable packaging and also continues to produce vacuum bags itself. "Our venture has worked out," reports Bielawski. "We have full order books - that's the best feedback for us from the market."