NC State
A.E. Ranger. Surface structure of coatings. In Papermaking Raw Materials, Trans. of the VIIIth Fund. Res. Symp. Oxford, 1985, (V. Punton, ed.), pp 673–685, FRC, Manchester, 2018.


The positive intercept which appears on a graph of K and N ink absorption versus a function of absorption time has previously been interpreted as a measure of surface roughness. In the case of coated surfaces, evidence is offered that it is an indicator of a porous top layer of the coating with distinctly different properties from those of the main part of the coating.

It is shown that the total void volume of this top layer depends on both the capillary suction exerted by the substrate and on the speed of drying of the coating and its pore size is intermediate between that of the substrate and the main coating layer.

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