In this article, two examples are presented that illustrate the development and manufacture of industrial biocides for coatings that reduce negative impact on human health and the environment.
The agrichemical, folpet, is shown to be an effective fungicide for use in a broad range of plastics including wood-filled plastics. Performance is evaluated through a tiered product development program utilizing: 1. Petri dish and environmental chamber accelerated laboratory testing of weathered samples and 2. the exterior exposure of panels or full-scale constructs (e.g., test decks). The action mechanism of folpet, a trichloro-methylthio-adduct, N-(trichloromethylthio)phthalimide, is discussed herein. The folpet active ingredient is additionally compounded into several physical forms that include resin and lubricant-pellet concentrates and granules for ease of processing into plastics and wood-filled plastic composites based on polyolefins, PVC and other resins. Data are presented that demonstrate protection from microbial defacement and deterioration at use-levels of 0.3 – 0.5% and treatment costs of cents per board-foot of composite without significant impact on physical properties. In addition, thermostability data for folpet and flexural properties of the finished wood plastic composite are presented. Air monitoring during extrusion operations shows that folpet-based products are easily handled safely in the work environment. A manufacturing case study is also presented.
