Moisture Balance
The state of thermodynamic balance where a textile fiber neither gains nor loses moisture to the surrounding air. When a material achieves equilibrium moisture sorption, the weight of the sample remains constant over successive measurements. This state depends heavily on the relative humidity and temperature of the laboratory.
Fiber Hydrophilicity
Different fibers exhibit distinct capacities to hold water based on their molecular structures. The equilibrium moisture sorption of cotton is significantly higher than that of polyester due to the abundant hydroxyl groups in cellulose. This difference dictates how each fiber behaves during wet finishing and dyeing.
Gravimetric Test
Measurement of this property involves drying the sample in an oven before exposing it to a controlled atmosphere. The equilibrium moisture sorption is calculated when the sample mass stabilizes within a minute margin over several hours. This test is crucial for verifying the commercial weight of bulk shipments.
Commercial Weight
Buyers and sellers use these values to adjust the invoice weight of fiber lots to prevent overpaying for excess water. When the equilibrium moisture sorption is reached, the raw material can be accurately priced using standardized commercial regain factors. This practice eliminates disputes over moisture differences between the shipping point and the destination port, protecting both transacting parties from financial loss.
