Conclusion

Increasing the paper's temperature and/or humidity promotes deformation, as the paper approaches its "glass transition temperature". This observation has led to the development of new calendering concepts (temperature gradient calendering, humidity gradient calendering, etc.) whose aim is to promote paper surface deformation, while preserving the core material. In this way, it is possible to partially offset the effect of increased calendering speed by applying higher temperatures to the metal rollers and increasing the length of the nip zone of the rollers in contact (which therefore implies an increase in contact time). What's more, since the pressures applied (linear force/length of nip) are also lower, it is possible to maintain interesting context properties.

The control of this thermomechanical treatment therefore depends on the control of heat transfer in...