Loss Rate
Mathematical evaluation of material degradation during thermal processing utilizes a ratio that defines the rate of mass reduction. This parameter, known as the mass loss coefficient, determines how much moisture or organic content a substrate loses under specific heat conditions. It provides a measure of the thermal stability of paperboard or coatings during drying or curing.
Thermal Stress
When board is exposed to high temperatures in an oven or during coating drying, it loses weight as moisture evaporates and volatile compounds are released. If the mass loss coefficient is too high, the board can become brittle and lose its structural strength. Controlling the drying profile prevents excessive weight loss and keeps the board within the desired moisture range.
Material Performance
Testing involves measuring the weight of a sample before and after exposure to a controlled heat source for a set period. This test allows converters to predict how the board will behave during high-speed printing or coating processes that generate intense heat. It assists in adjusting the dryer settings to prevent cracking or warping of the finished board.
In practice, maintaining a low coefficient ensures that the fibers retain enough moisture to remain flexible during the creasing and folding steps.
