ANDRITZ Biax line for BOPA production
BOPA (Biaxially Oriented Polyamide) film has excellent mechanical and barrier properties. It can be used for packaging of greasy and/or aggressive substances.
BOPA film is used for packaging of:
- Agricultural products
- Aquatic products
- Distilled goods
- Medical products
Characteristics and applications of BOPA films
BOPA films have special characteristics (tensile strength, burst and abrasion resistance, barrier qualities, gloss, transparency, and printing/laminating qualities) that make them ideal for packaging seafood, pre-cooked meals, greasy and salty foods, frozen/steamed foods, and so on.
BOPA film is also used for medical supplies (e.g. IV bags and sterilized instruments), for metallized designer balloons, and for electronic products. BOPA films are mainly laminated with PE, EVA, PET, CPP, and other materials.
ANDRITZ Biax biaxially oriented stretching technology for BOPA film production
For the production of sophisticated BOPA films, ANDRITZ Biax has developed the MESIM technology: a patented line for simultaneous stretching of the film. MESIM combines MD and TD stretching in one step. Better film properties and a significantly higher yield can be achieved with MESIM, producing a top-grade film.
Upstream equipment like units for raw material supply, extrusion, and casting, as well as downstream equipment such as a pull roll stand and winder are identical for both a MESIM and a sequential stretching BOPA line.
The extrusion system is equipped with main and co-extruder, which are oversized to provide the needed melt output with stable pressures and temperatures. Either single-screw or twin-screw extruders can be used. The melt is cast through a three-layer die onto a chrome-plated single cast roll and pinned down by an air knife (or alternatively, an electrostatic band).
After the film has passed through pre-treatment, it enters the MESIM oven. The film is stretched simultaneously in MD and TD direction. MESIM allows stretching ratios of 1:1-5.5 (MD) and 1:1-10 (TD). Shrink ratios are 1:1-0.5 (MD).
This unique flexibility allows for an optimized stretching process and minimizes the bowing effect.
Inside the pull roll stand, film thickness is measured by a high-precision X-ray system before the edges are trimmed. Corona treatment prepares the film for printing. Finally, the film is wound onto an automatic two-station turret winder.
BOPA film produced with MESIM technology offers unique opportunities to achieve better film quality, higher yield, and higher profit margins.
ANDRITZ Biax BOPA film line
|Thickness range||µm||10 – 30|
|Line width up to||mm||5,100|
|Output capacity up to||tons/year||6,600|
ANDRITZ Biax BOPA film characteristics
|Extraordinary resistance to oil, grease, solvents, and alkalis||Accommodates low temperatures (suitable for use in freezers)|
|Very good gas barrier properties||High dimensional stability|
|Excellent surface gloss||Good printability|
|Superb handling and treatability||Abrasion-resistant|