Patent ID: 10377077

Abstract:
A machine for manufacturing pre-stretched extendable film rolls provides for a pre-stretch unit (10) of the film (F) and a wrapping unit (100) of the film in roll provided with a series of rolls around which the advancing film is partially wrapped; the pre-stretch unit (10) provides for, in sequence, at least a first pre-stretching roll (12), a pre-stretching auxiliary roll (13) acting against the first roll (12) with the interposition of the film, and a second pre-stretching roll (14) having a speed greater than the speed of the first roll (12) to carry out the pre-stretching of the film; the wrapping unit provides for a wrapping roll (104) for wrapping the pre-stretched film; the pre-stretch unit (10) further provides for a detensioning roll (17) arranged downstream said second pre-stretching roll (14) and having a speed less than said second pre-stretching roll (14) and greater than said wrapping roll (104), so as to obtain a first detensioning of the film after the pre-stretching operation and a second detensioning of the film before the wrapping operation. A high quality pre-stretched film is obtained by this machine.