Hard Membrane Rust-preventive
Hard membrane rust-preventive solution "Chang-4" is Composed of tertiary-butyl phenol-formaldlyde resin as a basic membrane forming substance and some other resins of suitablequantities. When it is coated. the hard membrane gives good handle and stripping propertieswhich is not only lustrous but also clear. Through sifting and comparison in many tests, suitable quantities of corrosion-inhibitorsand some other additives are also added to the product. Thus its protetive properties are far-ther perfected. In atmospheric conditi ons this product gives good rust-preventive and salt spray-resistan-ce properties to many metals such as castiron, steed, brass, copper and aluminium. In other co-rrosive media its properties are definite too. Experiments show that it is a good material both for protective and decorative purposes.