Can GOLDEN Acrylics decay due to microbial contamination?
We as paint manufacturers add a biocide into all the water based products we produce. The purpose of this biocide is mainly for in-can preservation, to avoid the paint system from supporting any bacterial growth while still in the can. Some manufacturers, especially in the house paint market, also add a fungicide, which will reduce the chances of the dry film supporting the growth of fungus and spore type microorganisms. We do NOT use such fungicides, as we have not seen the need for such.

In our studies, we have found neither the wet paint nor the dry paint films support bacteria to any extent. As manufacturers, we carefully select raw materials and avoid using those that may prove to be good "food" for bacteria. The only raw material commonly used in acrylic art paints is the hydroxyethylcellulose type thickeners. The acrylic polymer itself is resistant to bacteria, and does not support its growth.

The only instances we have ever seen any wet paint being contaminated is where the paint was diluted extensively with water, and the pH of the system was near neutral (note: we formulate our products to be moderately alkaline, with a pH of 8.5 - 9.0, which also reduces the ability of bacteria to be supported). If our paint is diluted with several parts water per part paint, and stored for months, some bacteria can develop.

In very damp environments, mold can sometimes be noted to form on the paint and/or support surface. While we have seen our product can support mold in extreme conditions, we have chosen to NOT use fungicides as a result of our concern for the health and safety of our customers (most, if not all fungicides pose risks to the paint users).