Protective coatings

1. COATINGS

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

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

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 C C
R
R
R
R
R

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

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

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
1. What are the 3 components of paint?
2. What are 3 type of protection they provide?