In the process of metal processing and storage, the selection of anti-rust oil is very important. Solvent-dilutable anti-rust oil and displacement anti-rust oil are widely used due to their unique properties. There are significant differences in the use of additives in these two anti-rust oils, which directly affect their anti-rust effects and usage scenarios.
Solvent-dilutable rust-proof oil, as the name implies, is rust-proof oil diluted by solvent. Its main feature is that it contains volatile petroleum solvents, which evaporate naturally when used at room temperature, thus forming a uniform protective film on the metal surface. The additives of this rust-proof oil mainly include two categories: hard film-forming materials and soft film-forming materials.
Hard film-forming materials such as asphalt, resin (alkylphenol amino resin, tert-butylphenol methyl ester resin, petroleum resin, etc.), etc., will form a hard film on the metal surface after the solvent evaporates. This hard film is not sticky to the hands, dust and impurities, transparent or opaque, has good corrosion resistance, and can be easily washed off in petroleum solvents such as gasoline. However, its disadvantage is that it must wait for the solvent to completely evaporate before packaging or contact, otherwise it will cause the workpiece to stick. Therefore, hard film anti-rust oil is more suitable for rust prevention on the surface of large mechanical equipment, or for the sealing of raw materials and equipment stored in open air conditions.
Unlike hard film-forming materials, soft film-forming materials are mainly composed of oils and fats, such as lanolin and its derivatives, wax, vaseline, oxidized petroleum grease and its barium soap. After the solvent evaporates, these materials form an oil film, namely a soft film, which is relatively soft and can be easily wiped off. Soft film anti-rust oil is widely used in scenes that require long-term anti-rust protection due to its good anti-rust performance and long-term sealing effect. However, its unsealing process is relatively complicated and requires a certain amount of time and methods.
The main feature of replacement type rust preventive oil is its strong adsorption, and its main rust preventive is sulfonate. Sulfonate can replace the moisture and sweat attached to the metal surface, effectively prevent rust caused by human sweat, and form a firm protective film on the metal surface to prevent the invasion of external corrosive media.
Sulfonate, as the main component of replacement rust-proof oil, not only has strong adsorption, but also can form a dense protective film on the metal surface. This protective film can effectively isolate corrosive media such as air and water, thereby achieving the purpose of rust prevention. In addition, sulfonate rust inhibitors also have good water replacement performance, which can quickly replace the water on the metal surface, further improving the rust prevention effect.
In addition to sulfonates, other auxiliary ingredients are added to replacement anti-rust oils to improve their overall performance. For example, some replacement anti-rust oils add solvents such as ethylene glycol butyl ether to improve their solubility and fluidity; they also add ingredients such as salt spray reinforcing agents to enhance their salt spray resistance. The addition of these additives enables replacement anti-rust oils to exhibit excellent anti-rust effects in a variety of environments.
In summary, there are significant differences in the selection of additives between solvent-dilutable rust-proof oil and displacement-type rust-proof oil. Solvent-dilutable rust-proof oil mainly forms a protective film on the metal surface through hard film or soft film-forming materials to achieve rust prevention; while displacement-type rust-proof oil uses strong adsorption rust inhibitors such as sulfonates to replace moisture and sweat on the metal surface and form a strong protective film to achieve rust prevention. These differences make the two types of rust-proof oil show unique advantages in their respective application fields. In practical applications, the appropriate type of rust-proof oil and its additive combination should be selected according to specific needs and scenarios to achieve the best rust-proof effect.
