Moisture content (ISO 287)
Moisture content is expressed as a percentage of the
total paperboard weight.
As paperboard is a hygroscopic material, all testing
should be done in a controlled climate of 23 °C and
50 % RH.
It is also important that exposure during further
processing is under controlled temperature and RH
conditions.
Test method and equipment
The moisture content is measured and controlled
continuously on-line on the paperboard machine
by scanning equipment which gives a high degree
of definition in both the machine direction (MD) and
cross direction (CD) of the paperboard web. Laboratory
testing is carried out regularly to ensure correct
on-line calibration.