| 摘要 |
A method of cooling blown film consisting of thermoplastic plastics during the production of blown film by means of a blown film extruder with a film blowing head which comprises an annular nozzle from which the blown film emerges and is guided away in an extraction direction, wherein at least two cooling gas flows are made to approach the blown film from the outside in at least two blowing-out planes located at a distance from the annular nozzle, wherein at least one cooling gas flow K<SUB>G </SUB>is blown out in the direction opposed to the extraction direction of the blown film and wherein at least one cooling gas flow K<SUB>A </SUB>is blown out in the extraction direction of the blown film, and wherein, at least one of the cooling gas flows K<SUB>G</SUB>, K<SUB>A </SUB>can be controlled around their circumference in sectors, at least in respect of its volume flow or temperature. |
