Dynamic Spreading of Polar Liquids on Offset Papers

Abstract

The aim of this study was to investigate the spreading of sessile drops of polar probe liquids (water and ethylene glycol) on pigment coated offset papers. Furthermore, existing theoretical models for spreading were applied to evaluate the experimental results. The hydrodynamic model gave a better fit to the results at lower spreading rates, while the molecular-kinetic theory gave a good fit over a larger velocity range. Factors introduced to correct for the exponential dependency on time of the drop base radius and its contact angle can be interpreted as coupled processes. Differences in the spreading between the papers were found to correlate with the acid and base components of the surface energy, rather than with differences in surface roughness.

Understanding and Improving the Oil and Water Barrier Performance of a Waterborne Coating on Paperboard

“…The polymer dispersion will more easily penetrate the pores of the substrate reducing the amount of air/moisture entrapped, in both the substrate and inner layer of the coating, which will then result in less popping defects. 42 , 43 We can, however, not rule out the possibility that the presence of IPA could also have other effects that play a role in the film formation such as a plasticizing effect or acting as a coalescence aid. 40 , 44 , 45 …”

Radial Spreading of Inks and Model Liquids on Heterogeneous Polar Surfaces

“…The roughness, represented by drop base radius expansion, and the chemistry, represented by the contact angle, seem to be interrelated in the same way. For a larger data set [8] it was found that the correction coefficients do not agree with the trend of the RMS roughness, PPS values, or the Wenzel r-factor. The best correlation was found between the correction constants and the acid and base components.…”

“…The best correlation was found between the correction constants and the acid and base components. The correction coefficient seems to increase with increasing acid component σ A and decreasing base component σ B [8].…”

“…Summarizing the experimentally determined exponents of offset papers (published elsewhere in this journal [8]) and inkjet papers (unpublished results), the following general rules can be established:…”

“…Only a few examples is given here in order to illustrate the fits to experimental data. A more complete characterization of liquid spreading on offset paper surfaces are given elsewhere in this journal [8]. However, the modeling of liquid penetration is excluded from the present analysis.…”