Effect of Curing Agent Ratio
Effect of Curing Agent Ratio
With the rapid economic growth, the production and consumption of steel have increased rapidly, and the entire steel industry has also experienced rapid growth. At the same time, due to various causes of equipment damage and scrap due to steel corrosion each year, it brings huge economic losses and waste of resources and energy. Therefore, anti-corrosion engineering in steel applications has attracted more and more attention. The corrosion of steel is mainly damaged by the action of the surrounding medium. During the corrosion, chemical or electrochemical multiphase reactions occur on the surface of the steel to make the metal into an ionic state, the mechanical properties of the metal material such as strength and toughness are reduced, and the internal structure is destroyed. Shorten the service life of the equipment, and even cause the equipment to be scrapped. In steel anti-corrosion engineering, there are many methods and ways to prevent metal corrosion. So far, the use of anti-corrosion coatings is the most important, effective, economical, and most commonly used anti-corrosion method. Among them, the anti-corrosion performance of epoxy primer is particularly prominent Applied to the corrosion protection of steel.
The high-solid epoxy primer is divided into two components, A and B. The component A uses bisphenol A epoxy resin as the main film-forming material, and the component B is a polyamide curing agent. The polyamide curing agent contains active amino groups and can cross-link with epoxy groups in epoxy resin at room temperature to form a stable and dense network structure, so that the coating has good adhesion and anti-corrosion properties. The theoretical dosage of polyamide curing agent is calculated according to n (epoxy group): n (active hydrogen) = 1: 1. After mixing the high-solid epoxy primer with different curing agent dosages, the board is made and placed in a temperature and humidity control box for curing, the relative humidity is adjusted to 50%, and the adhesion of the entire coating is tested after it is completely cured. When the amount of curing agent is less than the theoretical value, the epoxy group in the epoxy resin cannot fully participate in the cross-linking reaction and cannot form a dense network structure, so the adhesion is extremely poor, especially the amount of curing agent is half of the theoretical value At the time, it showed a whole flaking phenomenon. When the amount of curing agent is 1.0 ~ 1.2 times of the theoretical value, the entire coating shows good adhesion. When the curing agent is 1.5 times the theoretical value, the adhesion will decrease. In application, considering various factors comprehensively, the dosage of the design curing agent is usually 1.0 ~ 1.2 times of the theoretical value.