BOPP lines with reduced energy consumption


Hall 3 | Booth C92

Increased working widths and higher line speeds are decisive parameters for increased performance. In recent years Brückner has repeatedly set new standards in these areas, including BOPP lines with 10.4m working width and speeds of over 500m/min and BOPETlines which are 8.7m wide and also operate at speeds of over 500m/min. At this year’s K show the company shows its latest developments for the production of oriented and speciality films.

High-performance BOPP extrusion line (photos: Brückner)

The first BOPP lines with over 625 m/min working speed

Brückner Maschinenbau will be introducing lines for the manufacture of BOPP films which can achieve working speeds of over 625m/min for the first time. The new development is based on a platform concept. Centrepiece is the new transport system in the transverse direction orienter (TDO) with increased operating stability at high speeds. A new longitudinal stretching unit (MDO) with automatically adjustable contact rolls ensures stable production conditions at high speeds. And a new low-vibration winding unit with an optimised contact roll guarantees high-quality winding and hence good quality film.

BOPET lines for packaging films

Nowadays, BOPET lines by Brückner operate at speeds of over 500m/min. Brückner will be introducing a number of new developments which will further improve the film quality and the operating stability.

For instance, the pinning of the film to the chill roll is further optimised by a completely new automatic control system. Standard materials can be processed at high speeds without additives such as pinning agents. Also the company’s longitudinal stretching unit with the unique “two-gap-stretching” has been fitted with innovative adjustments for a closed power flow. This results in high-quality film at speeds of over 500m/min, even for special applications such as very thin films. A newly designed low-vibration transport system in the transverse direction orienter (TDO) ensures optimal stability during operations in the high-speed range.

Reduced energy consumption

In all lines, the company continues to optimise constantly the possibilities for energy savings. In line with this trend Brückner will be presenting the new “HSE” high speed extrusion system.

The development of the fast-running HSE single screw extruder, especially as co-extruder for film stretching lines, is aimed to achieve the performance of several larger conventional extruders with considerably smaller screw diameters. The HSE extruder requires a smaller installation area, is easier to operate and less expensive to service. With regard to energy consumption a small extruder also provides advantages because it has lower radiation and convection losses. The direct drive also contributes to the lower energy consumption, because there are no energy losses resulting from the reduction gear. With regard to the process technology, the new extruder concept also leads to shorter dwell times of the melt in the extruder. This permits an improvement of the film characteristics and the purging and changeover times can be reduced.

Simultaneous stretching: the new LISIM generation

The new LISIM (linear-motor-driven simultaneous lines) series is specially designed for top-quality thinner films of between 0.5 and 75µm, including polyamide packaging films or ultra-thin BOPP and BOPET capacitor films. The new, less expensive system for the simultaneous stretching of thinner films demonstrates higher energy efficiency in the stretching oven, regarding the drive power as well as the ventilation system performance inside the stretching oven. A total of ten such lines have been in operation since 1998, designed for film thicknesses of up to 400µm.

LISIM SLC: sensorless control

Brückner’s patented simultaneous stretching technology is based on linear motor-driven individual clips, holding the film during the stretching process. This permits the plant operator a high degree of flexibility through the individual operation of each clip.

Through precise analysis of the current and tension, the sensorless regulation SLC (sensorless control) ensures that the stretching unit registers the load level of each individual clip at all times. Thus the power levels can be reduced to the required minimum in real time. In this way the power taken up, and hence the energy consumption, can be reduced by 40%. Furthermore, the line operator can pinpoint with high accuracy the forces to which the film is subjected. This provides him with precise knowledge of the stretching process and therefore permits optimisation compared with the mechanical process.

Lines for speciality films and battery separator films

The new process for the manufacture of high-quality battery separator films (Evapore), developed and patented by Brückner, has been well received by the market. Several orders for production lines have already been placed. At the exhibition Brückner will show how to reduce film thickness, in order to increase the power density of batteries, thereby reducing the construction volume. Also the processing of new materials in order to improve the temperature stability of the separator films, important in electrically powered vehicles (for instance UHMWPE – ultra-high-molecular-weight polyethylene), will be addressed.

And in regard to speciality film lines, the company will be presenting new concepts for high-quality simultaneously stretched polyamide films, extra-thin capacitor films under 3µm film thickness, technical and optical films (BOPET thick film up to 400µm) and PP multi-layer films (five, seven, nine layers).

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