(57) A machine (1) for making packaging material in the form of cushions (100) of air,
or other gas, comprises feeding rollers (21, 22) arranged to bring a web (10) of thermoplastic
material along a longitudinal conveying direction (101). The web (10) comprises two
films (10a, 10b) overlapped and can be unwound starting from a roll (20). When starting
the machine (1), the web (10) is put on a longitudinal guide (30) arranged downstream
of the feeding rollers (21) in the conveying direction of the web (10). The machine
(1) comprises a means (50) for heating the web (10), arranged to cause a local melting
the thermoplastic material along a longitudinal line (15). More in detail, the heating
means (50) comprises at least one heating rod (51, 52), which in use is arranged in
contact of the web (10) for causing a local softening to it. The, or each, heating
rod (51, 52) comprises an electric resistance (53) coated with an outer layer (54)
of a material having a low thermal transmission coefficient, for example less than
about 0,5 W/mK such as polytetrafluoroethylene (PTFE), or Teflon.
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