Antifouling paints cuprous oxide

The amount of biocides needed in an antifouling paint will be determined by actual tests performed in real life. A rule of thumb says that the minimum level of protection with copper is a leaching rate of 10 pg/(cm2 day) (WHOI, 1952). The amount of cuprous oxide can be up to 40 wt % of an antifouling paint and it is normally assisted by booster biocides (5 to 10 wt %) to provide full protection against both animals and algae. The amount of biocides will be based on practical performance and, at the same time, be restricted to given legislation. 

Ferry, J.D., Carritt, D.E. Action of Antifouling Paints. Solubility and Rate of Solution of Cuprous oxide in Seawater. Industrial and Engineering Chemistry, 38 (6) (1946), 612-617... 

Cuprous oxide has been used in the prepn of cuprous salts, in ceramics, fungicides, pyrotechnics, electroplating and in antifouling paints. These paints were used extensively by the US Navy during WWII (Refs 3, 6, 7 9 and Addnl Refs E F)... 

Visco-Stab. [Atochem N. Am.] Paint stabilizer, vise, stabilizer for cuprous oxide-containing paints based on bioMeT antifoulant polymen. 

In the soluble matrix type cuprous oxide and sometimes other biocides, is incorporated into a resin binder. The acidic resin slowly reacts with the sea water (pH approximately 8.0) and dissolves continuously exposing the cuprous oxide particles that are gradually released at the water/solid interface. The newly created surface provides antifouling properties. Depending on thickness the life of these paints on ships hulls, in contact with sea water, is 1 - 2 years. 

Black twisted nylon and polypropylene ropes used to rig and retrieve test platforms were unaffected. Grappling lines attached to platforms, made of steel wire jacketed with extruded high-density PE, prevented corrosion of the steel. PE is also used to protect submerged telephone cables. Plastic primers such as epoxy are used to prevent antifouling paints from corroding metals. These paints generally use cuprous oxide to prevent the growth of barnacles, but at the same time can be harmful to metal. 

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