Surfactant Migration Impact on Dynamic Surface Tension in Hardwood Stock
Residual surfactant migration in hardwood stock depresses dynamic surface tension below forty millinewtons per meter, triggering jetting print defects.
Cobb 60 Water Absorptiveness
Quantitative Evaluation
Standardized testing procedures evaluate the mass of water absorbed by a unit area of paperboard during a fixed interval of sixty seconds. The cobb 60 water absorptiveness provides a quantitative measure of the sizing efficiency and liquid resistance of a material intended for packaging. Results are expressed in grams per square meter and indicate the ability of the surface to withstand moisture during storage or transport.
Test Procedure
Technicians perform the test by clamping a specimen under a metal cylinder and pouring a specific volume of water onto the exposed surface. Once the sixty second duration concludes, the excess liquid is removed and the sample is weighed to determine the mass gain associated with cobb 60 water absorptiveness. This value directly correlates with the effectiveness of the chemical sizing agents added during the papermaking process.
Packaging Performance
Corrugated box manufacturers use this specification to predict the performance of containers in humid environments or during exposure to rain. A low cobb 60 water absorptiveness prevents the liners from softening and losing their structural integrity. High values often suggest a risk of delamination or adhesive failure when the board comes into contact with aqueous glues during the folding and gluing stage of production.
Proper control of surface sizing keeps the moisture uptake within the tolerances required for high speed converting.