Equilibrium Percentage
Standardized values for water retention in synthetic polymers define the difference between bone dry weight and commercial mass. The polyester moisture regain is set at a very low level, typically zero point four percent. This is the global standard.
Physical Basis
Lack of polar groups in the molecular chain prevents water from sticking to the polymer. Because polyester moisture regain is so low, the fabric dries almost immediately after washing. This characteristic prevents the material from sagging or stretching when wet.
It also means that static electricity builds up easily because there is no water to conduct the charge away.
Mass Correction
Weight adjustments in the factory use the official percentage to calculate the final price of a batch. Applying the polyester moisture regain ensures that the buyer is paying for polymer and not for the negligible water it might carry. In a blend of cotton and polyester, the calculation must be performed separately for each component.
These calculations are fundamental to accurate inventory management.
Processing Benefit
Low water retention allows for faster speeds during the dyeing and printing stages. Since polyester moisture regain is minimal, the energy required to remove water after a wet treatment is significantly lower than for cotton. This efficiency reduces the carbon footprint of the mill.
Modern production facilities track these values to optimize their oven temperatures.
