COATINGS

1. COATINGS

2. PAINT vs COATING synthetic resin or inorganic silicate polymer. resistant to harsh environments superior performance (adhesion, toughness, and resistance to chemicals, UV, etc.) drying oils and/or natural resins oxidation/evaporation to form a weather resistant film continues to oxidize and breaking down.

3. Basic Ingredients • Solvent (volatile) • Resin/Binder (nonvolatile) • Pigments (nonvolatile)

4. Solvents • Dissolve film former • Reduce viscosity for ease of application • Control rate of cure • Low molecular weight organic chemicals Examples include aliphatic, aromatic, and chlorinated hydrocarbons; alcohols; ketones; esters; glycol ethers; and water.

5. Resin (binder) • Principal ingredient • Holds paint together and to the substrate • Establishes chemical and physical properties • Defines coatings generic type • A "Vehicle" that turns to a "Solid" (nonvolatile)

6. Organic Coatings The resin is a carbon based polymer (urethanes, epoxies, alkyds, acrylics, etc) R R R C C R R R

7. Inorganic Coatings The resin is not a carbon based polymer Most utilize some type of silicate binder Zn Zn O O Si Si O O O O O Zn Zn

8. Type of Curing in Modern Coating Resins • Solvent evaporation • Oxidation • Chemical reaction • Catalyzed film former • Thermoplastic • Thermoset • Emulsion - water based

9. Pigment 1. Decorate, color, and hide 2. Protect • Barrier • Galvanic • Inhibitive 3. Provide consistency 4. Provide film thickness 5. Control vehicle penetration into substrate

10. Types of Pigmented Paint

11. Anti-fungus Anti-skinning Plasticizers Levelers Thixotropic agents Accelerators Stabilizers Additives

12. Life Expectancy of Coatings • design of bridge • suitability of coating to bridge type • environment • quality of paint • surface preparation • application • thickness

13. Coatings Review • What are the 3 components of paint? • What are 3 type of protection they provide?