What Is Anti-corrosion Film?
An anti-corrosion film is a film that is either mixed or coated with an anti-corrosion agent. It inhibits the formation of rust on the product it protects by preventing the ingress of oxygen and water vapor.
Anti-corrosion films contain a vaporizable rust inhibitor, making them essential for the quality control of metal products. Traditionally, surfaces have been coated with grease or oil to prevent rust.
However, these coatings need to be removed before processing or assembly, incurring labor and equipment costs and having an environmental impact. Anti-corrosion films prevent rust without the use of anti-corrosion oil, eliminating these issues.
For films that prevent oxygen and water vapor, the environmental impact is even smaller because no anti-corrosion film is used.
Uses of Anti-corrosion Film
Anti-corrosion film is used as a rust-prevention measure for metal products, including steel and non-steel materials. It is commonly used in the storage of automotive parts.
Automotive parts are often stored for extended periods and may be shipped overseas, where containers can be exposed to hot and humid conditions. In such cases, metal products are particularly vulnerable to rust, making anti-corrosion film essential.
Traditionally, these products were stored using double packaging: rust-proof paper for rust prevention and plastic bags for sealing. Anti-corrosion film can replace both of these functions with a single sheet, reducing costs. Sheet-type anti-corrosion film is also available in larger sizes for packaging large machinery.
Principle of Anti-corrosion Film
Anti-corrosion film is typically made from polyethylene or other plastics containing a vaporizable rust inhibitor. This inhibitor is effective in preventing rust. When the vaporizable rust inhibitor evaporates from the anti-corrosion film, it fills the sealed space.
During the evaporation process, the rust inhibitor dissolves into the metal surfaces within the space and the moisture in the air. This inhibits the electrochemical reactions that cause rust, effectively preventing rust formation. As the anti-corrosion film uses a vaporizable rust inhibitor, it can penetrate minute crevices that may be inaccessible by other coating methods, ensuring comprehensive rust prevention.
Furthermore, the anti-corrosion mechanism can vary depending on the type of corrosion inhibitor used. For example, nitrites used in anti-corrosion films for steel applications dissolve in condensation water, inhibiting the reaction of oxygen and water with the metal. Carboxylates of amines, also used in steel applications, dissociate into carboxylic acids, which then rejoin on the metal surface, providing corrosion protection.
Barrier-type anti-corrosion films, which do not contain vaporizable corrosion inhibitors, offer corrosion protection by preventing the ingress of oxygen and water vapor. Typically, rust occurs rapidly when humidity exceeds 60-70%, making it crucial to prevent moisture ingress to avoid such high humidity levels.
Features of Anti-corrosion Film
Anti-corrosion film, which serves to prevent rusting of metal industrial products, exhibits four main characteristics:
1. Dual Role of Rust Prevention and Packaging
Anti-corrosion film can simultaneously fulfill the roles of rust prevention and packaging with a single material, eliminating the need for separate packaging materials.
2. Elimination of Rust-Preventive Oil Removal and Cleaning
Unlike rust-preventive oil, anti-corrosion film does not require removal or cleaning processes before assembly, reducing production steps and costs.
3. Versatility in Rust-Proofing Methods
Anti-corrosion film can be applied in various forms, such as sheets, boards, zip-sealed bags, and cushioning materials, making it adaptable to different product sizes and packaging conditions.
4. Reduced Environmental Impact
Anti-corrosion film is not liquid or paste-like oil or grease, minimizing the risk of contaminating the factory floor or soil due to dripping and reducing the environmental impact.