The requirement to easily remove stains from latex wall paints is nowadays an increasingly common standard in paint formulations not only of the premium class, but also of the higher-end random paints. Raw materials such as polymer dispersion, thickeners, surfactants, specially added additives, fillers, pigment volume concentration, etc., are responsible for the easy removal of stains.
However, even after removing the stain, there is a risk that the coating will be permanently changed in some way. I omit here the decrease in the thickness of the coating caused by washing the stain, as this should not occur at all, and the problem of the permanent stain remaining on the coating is also neglected. In this case, it is about increasing the gloss and sheen of the coating, which is the result of the action of wet washing with various detergents. Assuming that a soft sponge, e.g. a polyurethane sponge with a detergent, e.g. dishwashing soap, is used to wash stains from the walls, it should be taken into account that various dishwashing detergents have a different composition and may have a more or less aggressive effect on the latex paint coating. This is illustrated by the example below.
The photo above shows the coatings of latex paint prepared at the Spektrochem Paint Technical Center (PVC 33 %, PCC filler, titanium dioxide pigment) with an initial gloss level 2 in accordance with MPI #44 (velvet like: @ 60° max. 10 and @ 85° 10 – 35), which was subjected to washing tests with two detergents, and then the gloss was determined again with a Rhopoint Novogloss Trio glossmeter according to ASTM D523.
Detergent A (left), after 100 washing cycles in a scrubbability apparatus with a cellulose sponge as per ASTM D3450, increased the gloss by 8 % at 60° and 21 % at 85°. In turn, detergent B (right) in the same test showed that the coating showed a drastic increase in gloss, by 430 % at an angle of 60° and 121 % at an angle of 85°.
In the case of formulations of paints with increased easy-to-wash stains, do not forget to recommend appropriate detergents that will allow consumers not only to wash everyday stains from the coatings, but also narrow the group of recommended detergents to those that will allow the stains to be removed without causing local coating defects, as in the case of example, a drastic increase in gloss at the stain removal site.
In the Spektrochem Paint Technical Center, formulations are prepared in terms of the selection of raw materials, such as dispersion of polymers, fillers, additives and others, in order to develop recommendations for useable detergents, both for removing stains and determining their aggressiveness in washing tests and causing local defects in coatings. . You can see more in our short video below.