The prevention of corrosion in packaging. I. The use of sodium benzoate as a corrosion‐inhibitor in wrappings

Sodium benzoates and other soluble benzoates can be used for the production of corrosion‐inhibitive wraps by impregnation in materials such as paper, strawboard, regenerated‐cellulose films and waxed papers. Provided the chloride content of the wrap is sufficiently low before impregnation, complete protection is effected for steel under adverse conditions of storage or transport. The corrosion of common non‐ferrous metals is in no case increased; in some cases it is substantially reduced or (e.g. solder and soldered joints) suppressed. For the protection of cast‐iron surfaces it is necessary to introduce a nitrite (e.g. sodium nitrite) into the wrap; the aggressiveness of nitrite towards solder is then prevented by the joint presence of sodium benzoate, in appropriate ratio. Sodium salts of other organic acids show promise as corrosion‐inhibitors in packaging materials.