Types of Paint Coatings and Their Curing Mechanisms

Paint coatings have become integral to our daily lives and work environments. From solid wood furniture at home to components in office electronics, spray-painted parts are ubiquitous. The role of paint coatings varies depending on the product.

Wooden paint coatings serve primarily decorative and preservative purposes. However, modern technology demands more than mere aesthetics and corrosion resistance. Thus, scientists have endowed paints with capabilities such as camouflage, heat resistance, conductivity, high-temperature insulation, anti-soiling, radiation protection, and even optical filtering.

Coatings can be classified based on the type of substrate they cover:

• Metal Baking Paint: Used on metal surfaces.
• Concrete or Stone Spray Paint: Applied to concrete or stone materials.
• Plastic Spray Paint: Designed for plastic substrates.
• Wood Spray Paint: Specifically formulated for wood.
• Quartz Glass Spray Paint: Used for quartz glass substrates.

Coatings can also be categorized based on the mechanism of film formation:

• Volatile Coatings: Formed by solvent evaporation.
• Oxidative Polymeric Coatings: Polymerize and form a film through oxidation.
• Thermosetting Coatings: Require temperatures above 100°C for solvent evaporation and loss of flowability. Crosslinking and curing of functional groups within the coating molecules occur at these temperatures, forming a complete polymer layer. Examples include amino-resin baking paints, asphalt varnishes, and organosilicon magnetic paints.

Amino resins serve as curing agents for alcohol-acid resins in the paint industry. Under heating conditions, ether bonds in amino resins crosslink with hydroxyl groups in alcohol-acid resins, curing into a film. This curing process must occur within a specific temperature range.

Each resin paint has a designated baking temperature critical to its production process. Deviating from this temperature range can lead to polymer chain breakage or degradation of pigments, causing discoloration. For instance, amino-resin baking paints require drying temperatures between 120°C and 140°C. Prolonged exposure above 150°C results in discoloration, brittleness, and reduced durability, thereby compromising the decorative and protective functions of the coating. Conversely, temperatures below 120°C prevent film formation, necessitating precise temperature control during production.

The drying principles and temperatures vary depending on the substrate and coating composition. Coatings broadly fall into oil-based and water-based categories, each with complex compositions. Matching infrared absorption principles to the paint’s infrared characteristics optimizes drying efficiency when using carbon fiber heater elements, enhancing infrared radiation energy utilization.

GlobalQT (Global Quartz Tube) is a leading manufacturer of quartz tubes and quartz tube heaters. For more information, visit our website or contact us via email at contact@globalquartztube.com.