Capillary Sorption Anomalies under Dynamic Surface Tension Gradients in Recycled Paperboard Substrates
Dynamic surface tension gradients in recycled paperboard cause capillary stalling, uneven ink penetration, and severe converting spoilage.
ASTM D5455
Absorption Assessment
Standard testing protocols for paper absorbency evaluate the volume of liquid taken up by a specimen over short time intervals. The protocol described in ASTM D5455 governs the measurement of water or other liquids absorbed by paper and paperboard during contact times ranging from milliseconds to seconds. This method is particularly relevant for assessing how printing papers behave during high-speed printing runs where ink solvent must penetrate the surface rapidly.
It provides a standardized framework for manufacturers to test raw stock before it enters the high-volume converting lines.
Transfer Speed
Liquid contact times during industrial coating or printing are extremely brief. High-speed liquid application requires the paper to develop immediate contact with the fluid, a property evaluated through automated scanning of a droplet on the surface. Factors like roughness and surface energy influence the rate, but this test isolates the pressureless absorption behavior of the sheet under controlled temperature conditions.
Boundary Limit
Porous structures with high initial absorption can deplete ink vehicles too quickly, which leads to poor gloss or ink binding. Low absorption values conversely cause offset or ink smearing in high-speed machinery. The applicability of this test is restricted to non-absorbent or moderately absorbent grades, as highly absorbent tissue or blotting papers saturate too quickly for the sensors to record accurately.