1 -8 BASIC KNOWLEDGE ABOUT PAINTS AND PAINTING 2. REACTION TYPE In this type of paints, the solvent and thinner in the paint evaporate and, in addition, resins are hardened and dried by a chemical reaction (called polymerization). The following illustrates the molecular change of the resin. The fresh paint is a soft coat in which pigments, resins, solvents and thinners are mixed thoroughly. IMMEDIATELY AFTER APPLICATION The solvent and thinner evaporate during drying, and resin molecules are gradually connected to each other through a chemical reaction. DURING DRYING D The coat is completely free of solvents or thinners.
The chemical reaction of the resin molecules is completed and they form a net-like coat. AFTER DRYING In reality, molecules form a three-dimensional net rather than a two-dimensional net as shown above. This type of reaction is called polymerization, and, once the paint has dried completely, it forms a very strong coat that cannot be dissolved by a solvent. - 10-