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Difference between revisions of "Biocomposite processing"
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added blown film extrusion as a method o post treating the biocomposite.
Stef Denayer (talk | contribs) |
(added blown film extrusion as a method o post treating the biocomposite.) |
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* [[Sizing|Cutting]] | * [[Sizing|Cutting]] | ||
*Blown film extrusion | |||
Biocomposite pellets are processed in an extrusion line machine, forcing the melt through a narrow slit die. The resulting thin film has the form of a tube also called a “bubble” (blown film). | |||
Film blowing is a process of producing film by extrusion of molten biocomposite polymer into a continuous tube. The elements of the process include the resin pellets which are fed through a hopper into the extrusion line. Heat and friction convert the pellets to a melt which is forced through an annular or ring-shaped die to form a tube. The tube is inflated to increase its diameter and decrease the film gauge. At the same time, the tube is drawn away from the die, also to decrease its gauge. The tube, also called a “bubble,” is then flattened by collapsing frames and drawn through nip rolls and over idler rolls to a winder which produces the finished rolls of film. | |||
As the tube inflates, its thickness becomes uniformly thinner as orientation in the transverse direction occurs, allowing a variety of thicknesses to be produced by combined control of the extruder throughput, inflation, and roller speed. As the inflation diameter increases relative to the annular die size, material orientation is increased and this ratio is known as the blow-up ratio. The extrusion die is shaped as a circle and air pressure is used to further expand the film. After it is expanded to the desired dimensions it is cooled to solidify the biocomposite polymer. | |||
== Technology providers == | == Technology providers == | ||