Paint consists of several components, including resin, hardener, pigments, additives, and solvent. Paints containing colored pigments are commonly referred to as “enamel”, while those without pigments are called “clear paint”.
1. Liquid Paint and Powder Coatings
Paint is composed of a mixture of resin, hardener, pigments, additives, and solvent. The solvent evaporates during painting and is not present in the final coating. Paints containing colored pigments are commonly referred to as “enamel paints,” while those without pigments are called “clear paint”. The majority of practical paints are enamel paints. Additionally, resin, hardener, and solvent are collectively known as “vehicle” in the context of coatings. Vehicle solids refer to the solid components that form the continuous film. Binder is synonymous with vehicle solids, with its primary component being resin. Detailed information about paint composition is provided in the diagram.
2. Selection of Resin and Hardener
The choice of resin and hardener significantly impacts the performance of paint. Different types of resins are chosen based on the application. For example, epoxy resin with strong adhesion is used for metal primers, while acrylic resin is used for topcoats that require durability and transparency in the face of sunlight exposure. Additionally, there are various options for how paint can dry and cure, including solvent-based drying, oxygen-curing coatings, and coatings that cure through baking.
Pigments come in different types, such as coloring pigments to add color, rust inhibitors to prevent corrosion, and fillers to enhance texture. The choice of pigments not only affects color and durability but also plays a significant role in properties like the hardness and spreadability of the coating. Solvents are used to improve the flowability of paint, ensuring a smooth and uniform coating, eliminating bubbles, and adjusting drying times. Additives are employed to alter paint characteristics and aid in achieving even pigment dispersion. From an environmental perspective, there is a push to reduce the use of organic solvents and transition to powder coatings, water-based coatings, high-solid coatings, and solvent-free coatings.