Does concrete oily release agent provide rust prevention?
Publish Time: 2025-09-12
In the production of precast concrete components, steel formwork is a reusable core tool. Its surface condition directly impacts demolding quality, component appearance, and service life. This is especially true in high-strength, high-frequency steam-curing applications such as pipe piles, square piles, and hydraulic sheet piles. Steel formwork is exposed to harsh environments of high temperature, high humidity, and alkaline corrosion for extended periods, making it susceptible to oxidation and rust. Once the formwork rusts, it not only reduces demolding efficiency but can also cause pitting, color variations, and even mold adhesion and breakage on the concrete surface. Therefore, it is crucial to select a release agent that provides both efficient demolding and rust prevention. Concrete oily release agents, with their unique chemical composition and film-forming properties, are becoming an ideal solution for both demolding and rust prevention.1. Oily Matrix: A Natural Metal Protective BarrierConcrete oily release agents are typically formulated with a base of mineral oil, synthetic oil, or vegetable oil, supplemented with film-forming agents, stabilizers, and rust-inhibiting additives. Compared to water-based release agents, oil-based products inherently have extremely low polarity and excellent hydrophobicity, forming a dense, continuous, and water-impermeable oil film on the steel mold surface. This oil film not only effectively isolates the concrete slurry from the metal surface, preventing the chemical reaction between calcium hydroxide in the cement and iron (known as "alkaline corrosion"), but also blocks atmospheric moisture and oxygen from reaching the steel mold surface, fundamentally inhibiting the occurrence of electrochemical corrosion. This physical isolation mechanism allows the oily release agent to continue its rust-preventing effect even when the mold is not in use or stored overnight, making it particularly suitable for open-air precast sites in humid southern regions or during rainy seasons.2. Adding Specialized Rust Inhibitors: Proactive Chemical ProtectionHigh-end oily release agents go beyond the physical coating of the base oil and incorporate additional corrosion-inhibiting additives such as sulfonates, amine compounds, or organophosphates. These active ingredients adsorb to the metal surface, forming a molecular-level protective film that prevents the ingress of corrosive media, even in areas where the oil film is locally worn or thinned. These additives exhibit self-healing properties, continuously releasing their protective properties during repeated mold use, extending the rust-proofing cycle.3. Resistant to high-temperature steam curing environments, maintaining stable rust-proofing performancePrecast pipe piles, square piles, and other components commonly utilize steam curing processes, with curing temperatures often exceeding 80°C or even 100°C. Under these high-temperature and high-pressure environments, ordinary coatings or water-based release agents are susceptible to decomposition, volatilization, or carbonization, losing their protective properties. High-quality oily release agents, however, utilize a high-flash-point, thermally stable base oil, combined with high-temperature-resistant additives. These agents maintain the integrity of the oil film during the steam curing process, preventing cracking, blistering, and carbon deposits. This ensures that the mold surface remains pristine after demolding, eliminating the need for frequent sanding or repainting.4. Reduced mold wear and extended mold service lifeRust on steel molds not only impairs mold release but also increases surface roughness, leading to increased concrete adhesion and demolding resistance. In severe cases, this can cause mold pulling or chipping. Long-term rust also weakens the mold's structural strength, shortening its overall service life. Oily release agent provides continuous rust protection, maintaining a smooth mold surface and minimizing mechanical damage and chemical corrosion. This allows the same steel mold to be reused thousands of times, significantly reducing equipment replacement costs.5. Easy Application and Strong CompatibilityOily release agent can be quickly applied by spray, brush, or roller. After drying, it forms a uniform oil film that does not affect subsequent concrete bonding. It is highly compatible with all types of prestressed steel bars, steel plates, and common concrete admixtures, preventing problems such as bubbles, delamination, or strength loss.Concrete oily release agent is not only an effective mold release material but also a practical mold protectant. Its dual mechanism of oil film isolation and chemical rust prevention provides a durable and reliable anti-rust barrier for steel molds even in harsh working conditions such as high temperature, high humidity, and strong alkali. For production lines of large-volume, high-turnover prefabricated components such as pipe piles, square piles, and hydraulic sheet piles, the use of an oily release agent with rust-proofing capabilities can not only improve demoulding efficiency and component appearance quality, but also significantly extend mold life and reduce overall operating costs, providing a strong guarantee for achieving green, efficient, and sustainable production.
