Dicyandiamide in Coatings: Performance and Application Analysis
Feb 10, 2025| Exploration of the Application of Dicyandiamide in the Coating Field
Dicyandiamide, also known as dicyano diamine, is an important organic compound widely used in the coating field.
The Principle of Dicyandiamide in Coatings
Dicyandiamide is mainly used as a latent curing agent in coatings. Take its application in epoxy coatings as an example. After being mixed with epoxy resin, it can be stored at room temperature for a long time. Once heated to near its melting point, dicyandiamide begins to dissolve and react rapidly with the epoxy resin to cure. The four active hydrogens and the cyano group in the molecular structure of dicyandiamide can all participate in the curing reaction as functional groups, enabling the epoxy resin to form a cross - linked structure and significantly improving the performance of the coating.
Applications of Dicyandiamide in Different Coatings
Powder Coatings
Dicyandiamide is an early - industrialized curing agent for epoxy powder coatings. The epoxy powder coating cured by dicyandiamide at high temperatures has a very light film color, does not turn yellow, and the film has excellent chemical corrosion resistance, abrasion resistance, mechanical strength and other properties.
Anticorrosive Coatings
The epoxy anticorrosive coating cured by dicyandiamide can resist complex and changeable corrosive environments due to its excellent mechanical properties and chemical corrosion resistance. For example, in fields with harsh corrosive environments such as the chemical industry and the marine industry, it can provide reliable protection for equipment, pipelines, etc.
Other Coatings
Dicyandiamide also plays an important role in fields such as thermosetting inks and laminate coatings. The good adhesive properties, heat resistance and stable storage period of the dicyandiamide - epoxy resin cured product enable it to meet the requirements of these coatings in different application scenarios.
Advantages and Disadvantages of Dicyandiamide in Coating Applications
Advantages
It has high purity, good chemical stability and heat resistance. When used in combination with epoxy resin, the coating can obtain excellent properties after high - temperature curing, and has a long storage period at room temperature.
Disadvantages
The curing temperature of dicyandiamide is relatively high, usually around 160 - 180 degrees Celsius, and the curing reaction time is 20 - 60 minutes. In addition, the insolubility of dicyandiamide in epoxy resin may lead to uneven cured coatings and increase the water sensitivity of the cured film.
Improvement Directions of Dicyandiamide Applications
To overcome the high curing temperature of dicyandiamide, curing accelerators are often added, such as substituted urea accelerators, to reduce the curing temperature and shorten the curing time. Dicyandiamide can also be modified. For example, using silica and γ - glycidoxypropyltrimethoxysilane to modify dicyandiamide can improve its performance in coatings.