Thermoset of PP and PET

[DrenthHolland]

Hello!

We supplie a wide range programme of technical fabrics, machine stretching, wire mesh belts and filtration belts, woven from metal wire, plastic threads and/or a combination of these.

We give the PP and PET belts a thermoset treatment (heattreatment) to ensure that the belt won't shrink when it is used on a beltconveyer.

Is there someone who can tell me what happens to the material when given this treatment? We know that it works but we don't exactly know what happens to the structure of the material. What is the influence of the tension in the material? We would like to get more information about the proces to be able to predict how the belt will react during and after the heattreatment.

Kind regards,

Hans

 

[rnd2]

Thermo plastics have 'memory' in that when cold stretched or cold worked to cause them to plastically deform, and later, the temperature is raised somewhat above the cold worked temperature, the plastic will attempt to return to its original shape. The industry of heat shrink tube and tape products is based on this phenomenon.
What you are doing by heat treating the finished product is a form of stress relieving. By the way, thermosetting is a term that should be reserved for thermosetting resins which are quite distinct from thermo-plastic resins such as the PET & PP you are using.