Bacteria, yeasts, and fungi in production plants are detrimental to paints and coatings. And they cause wide-ranging customer complaints: In most cases, changes in viscosity, odor build-up and discoloration result in a total loss, which costs companies money and tarnishes the manufacturer’s reputation.
The solution is to add the right preservatives to the paints to prevent such damage. They must fulfill both technical and health requirements and be kept up-to-date consistently. In the past, paints and coatings were often protected with MIT (methylsothiazolinone). However, EU authorities have prohibited its use since May 2020 because it causes skin sensitization. As a result, paint and coating producers are looking for new, reliable and long-lasting in-can preservation methods for aqueous paint and coating systems, without needing the H317 label (May cause an allergic skin reaction) on the paint can label.
Finding a Suitable Antimicrobial Additive
Finding the right additive for a particular product requires precise knowledge of microbes and their behavior in and on paint. Antimicrobial combination products such as zinc pyrithione and BIT (benzisothiayoline) have proven to be effective during in-can tests. This combination can essentially increase the effectiveness of individual, active raw materials despite using smaller quantities.
Water-based paints and coatings have an increased risk of contamination. For this reason, microbe ingress must be prevented as early as during the production process in addition to protecting products during storage. Early intervention is paramount since microbes grow and multiply exponentially in favorable conditions. In laboratory tests, 1 microbe turned into 1 million microbes in just seven hours.
In-Can Preservation
Storage also has its very specific challenges, such as a microbial growth surge caused by insufficient or improper preservation. The microbes grow in cycles and feed on dead cells, among other things. This property increases the risk of contaminating the finished product and may reduce storage stability to just a few days.
There are basically four key components that foster and accelerate microbe growth: moisture, heat, food source, and time. Microbes cannot grow when at least one of these conditions is eliminated or if paint is absolutely free of microbes due to optimum hygiene during the production process. For paints and other products, it is often not possible to eliminate one of these growth-supporting components since it would eliminate the product's properties. The correct in-can preservative must be used to maintain these technically required, optimum conditions.
«Combination products make it possible to compensate for the weaknesses or even gaps in the effectiveness of individual biocidal agents, which effectively eliminates all potential microbial impurities,» explains Timo Schock, Technical Manager at SANITIZED Preservation AG in his feature article in the German «Farbe und Lack» magazine for paint and coating experts.
Hygiene Audits Lend Support
Managing processes correctly and consistently implementing hygiene audits is crucial for reducing microbes.«Hygiene requires an active commitment,» adds Timo Schock. SANITIZED Preservation AG has specialized in protecting the entire production and supply line of paints and coatings up to and including their application.
