Investigating propensity of roller spatter during application of water-based architectural paints: effect of thickeners and volume solids

During roll coating application of water-based architectural paints, fibers are formed between roller and substrate. These fibers progressively thin and break up into several tiny droplets leading to the wastage of paints. This defect is widely known as spattering. In the current study, the propensity to spatter in fully formulated mid pigment volume concentration water-based architectural paints based on varying the type of thickeners, namely a combination of cellulosic with clay, cellulosic, and hydrophobically modified poly acetal/ketal polyether (HMPAPE), at similar and varying volume solids is investigated. The spatter tendency of paint is qualitatively assessed using ASTM D4707. Also, a new approach to quantify the spread area of spattered droplets is developed by thresholding-based image segmentation using an image processing toolbox of Mathematica. This newly developed quantitative approach will greatly help the formulator to better differentiate between formulations. Rheological tests, namely viscosity curve, amplitude sweep, frequency sweep, and first normal stress difference test, are carried out to unravel the flow and viscoelastic properties of paints in depth. An in-house custom-built fiber drawing device on a contact angle drop shape analyzer instrument is fabricated to study the extensional properties of paints. At the same volume solids, the paint based on a combination of cellulosic with clay thickener spatters the most, while the paint based on HMPAPE thickener spatters the least. This is mainly attributed to the chemistry, molecular weight, and thickening mechanism of thickeners. Eventually, a reliable correlation is established between observed spatter and the frequency-dependent elastic modulus outside the linear viscoelastic range at the same and varying solids for paints based on the different types of thickener. This correlation will help chemists to quickly screen formulations to minimize the spattering during roll coat application, thus saving time, cost, and manpower.