ANDRITZ Biax line for BOPS film production
Due to their excellent stiffness and transparency, BOPS (Biaxially Oriented Polystyrene) films and sheets are mainly used for thermoforming, envelope windows, and shrink film products.
Biaxially Priented Polystyrene (BOPS) is used forBase sheets and films for thermoforming:
- Colored films
- Laminated films
- High transparency films (lids, labels and in-mold labels)
- Twist wrap
Characteristics and applications of BOPS films
BOPS film is characterized by high transparency and gloss, and by its resistance to acid and alkaline solutions, salts, soaps, and detergents. It is odorless, neutral in flavor, and easy to cut and print.
BOPS film is mainly used as thick film for thermoforming applications or thin film for flexible packaging applications.
The largest application for BOPS is thermoforming. Due to its high transparency and gloss, as well as its good stiffness and formability, BOPS sheets are converted into food trays and containers for fresh produce, pastries, and desserts. BOPS is also used for blister packaging of medical products, cosmetics, and electronic gadgets.
Labels and sleeves
BOPS film is printed and converted into labels and sleeves for bottles and containers, as well as for in-mold labeling.
BOPS, laminated with aluminum, is used for production of lids (e.g. dairy products).
High transparency film
Due to its transparency and stiffness, thin BOPS film is used for envelope windows.
ANDRITZ Biax technology for BOPS film production
ANDRITZ Biax supplies lines for BOPS film or sheet or for combination lines.
- Twin-screw extruders are preferred for processing PS due to their ability to mix, degas, and homogenize the different resin grades and additives. Continuous melt filters and vapor-heated melt pipes provide excellent temperature uniformity and also filter and transport the melt to the die.
- Proprietary mono-layer dies with feed block are used to produce a wide thickness range. Fast heating die bolt control, easy lip cleaning, and fast die lip dismantling are important features. When required, different dies can be arranged on a special die carriage for quick change-out. This is particularly important for multi-purpose lines.
- The casting unit has a three-roll calender (roll stack), which can be configured to match the film thickness range.
- The MDO is equipped with driven rolls that are heated by a Caloduc direct heating system (IR heaters to vaporize thermo-oil in the roll jackets) for an optimum surface temperature tolerance of +/- 0.5 °C. Single-gap stretching allows stretching ratios from 1:1 to 1:5.
- ANDRITZ Biax’s well-proven monorail system with high-speed sliding clips is employed in the TDO. Stretching ratios up to 1:10 can be accommodated. The TDO oven is directly heated (gas, electricity, or fuel oil). The heated air is applied to the film through specially designed slot nozzle boxes.
- The pull roll stand is equipped with an X-ray thickness measuring system, edge trim unit, and Corona treatment. A silicone coating system (for thick film thermoforming applications) can be installed inline.
- Depending on the film or sheet type, winding is accomplished with a one- or two-station turret winder, or multi-web winding unit.
- An advanced control system, fully redundant and reliable, is included. Profibus DP intercommunication and Ethernet allow user-friendly and easy operation.
ANDRITZ Biax also offers a wide range of downstream equipment, such as mill roll handling and storage, primary and secondary slitting, and recycling solutions for BOPS plants.
If desired, a complete turnkey solution for BOPS film production can be provided.
ANDRITZ Biax BOPS film line
|BOPS film||BOPS sheets|
|Line width up to||mm||6,700||4,200|
|Output capacity up to||tons/year||15,000||22,000|
BOPS film characteristics
|Superb printability||High clarity|