Method of producing a single or multiple layer expandable film

摘要

The method involves placing the molten film (1) in a gap (6) between two surfaces and is cooled at a surface by contact cooling. The molten film is placed between a rotating cooling roll (5) and a smoothing strip (7) for limiting an expansion of the expanding substance. The surfaces of and expansion of a substance opposes a counter pressure and supports these at both sides of the molting film so long till the molting film is dimensionally stable by cooling the polymer melt.