Method and apparatus for the reduction of the sag and/or of the varying stress profile of a flattened tubular film web produced by a blown film process

摘要

The invention refers to a method for the reduction of the sag and/or of the different stress profile of a flattened tubular film web produced by a blown film process and made of thermo-plastic synthetic resin, transversely to its longitudinal direction. For the solution of the problem to provide a method according to which the sag and/or the different states of tension transversely to the tubular film web can be easily reduced or eliminated to a maximum degree, the tubular film web is heated along its width and then cooled and/or stretched. Furthermore, the invention refers to an apparatus for carrying out the method.