Cooling efficiency, melt blowing

While diameter of extruded tube increases due to blowing via inner air (for higher product efficiency its temperature could be controlled), it is in meantime withdrawn away from the die and cooled from outside. The finished film is thus formed between the die and frost line, defined as point where film is changed from the melt to the solid state, by the simultaneous blowing and drawing of the tube of hot melt extruded from the die. 

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