Epoxy based powder coatings were the first
thermosetting system to become commercially available and
are still widely used today. Epoxy coatings are used primarily
as functional coatings for substrate protection where inherent
toughness, corrosion resistance, flexibility, and adhesion
are required. The primary limitation of epoxy-based coatings
is poor weatherability.
Typical applications include pipe coatings, electric meters, metal furniture,
shelving, electrical parts, refrigerator liners, dryer drums, and high voltage
switchgear.
| Pretreatment |
Iron
phosphate, zinc phosphate |
Advantages |
Excellent
chemical resistance |
| Application
Conditions |
Electrostatic
powder spray, fluidized bed |
|
Gives
low gloss, matte finishes |
| Film
Thickness |
1.2
- 100+ mils |
|
Smooth
coatings |
| Specific
Gravity |
1.2
- 1.8 |
|
Good
corrosion resistance |
| Coverage |
107.0-160.0
sq.ft./lb. per mil of coating |
|
Good
mechanical properties |
| Baking
Schedules |
5
minutes at 399º F |
|
F-5H
pencil hardness |
| (Standard
Cure / |
10
minutes at 375º F |
|
Excellent
adhesion to substrate |
| Metal
Temperature) |
15
minutes at 320º F |
|
Excellent
electrical properties |
|
|
|
Very
good abrasion resistance |
|
|
Disadvantages |
Chalks
when exposed to UV |
|
|
|
Poor
UV resistance |
Epoxy Standard Cure Schedules
The data below
is based on 20-gauge steel panels. For heavier ware,
higher temperatures or longer oven times may be necessary.
Low Gloss or textured finishes may require
a slightly longer cure.
|
