Tecnova double bubble extrusion line

Reference: E21002
Machine manufacturer Tecnova
Model Double bubble
Year 2006
Layers 3
Diameter screw(s) 1 x 60
1 x 90
L:D ratio screw(s) 1 x 30D
1 x 33D
Max. web width 1780 mm
Max. output 104kg/h
Type of winding Double for flat film
Tower construction included Yes
Available from Now
Machine can be seen in production Yes
Subject to unsold. Although believed to be correct, the machine specifications and lists supplied are based solely upon those provided by the original owners.

Machine used the double bubble extrusion process. In the double bubble process, the polymer is extruded as a tube into a water bath. The water rapidly quenches the polymer, reducing its crystallinity compared to conventional air quench blown film. The lower level of crystallinity helps in the subsequent orientation process.

Following quenching the tube is reheated to the orientation temperature using a hot water bath or IR heater. This two-step process of quenching and reheating the tube helps control the crystallinity as well as produces a more uniform temperature for orientation. The tube is expanded by blowing air inside the tube similar to a conventional blown film process. A difference is that in the double bubble process the tube is oriented at lower temperatures, producing higher stresses during orientation. Stretch ratios are also typically much higher than in conventional blown film. As a result, double bubble films have more orientation than conventional blown films. Melt strength is also not a factor as it is in the blown film process.

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