Urethane-cured
polyester powder coatings combine very smooth, exceptional
thin film capability,
with excellent mar and chip resistance, and good weathering
properties. Adhesion to properly prepared (pretreated)
substrates will provide very durable coatings with long-term
resistance to humidity and corrosion. Polyurethanes
are typically resistant to many diluted aqueous acids, salts,
aromatic and aliphatic hydrocarbons, grease, and oils.
Typical applications utilizing polyurethane
coatings include fluorescent light fixtures, lawn and garden
equipment, electrical enclosures, playground equipment, range
panels, air conditioners, automotive trim, and patio furniture.
| Pretreatment |
Iron
phosphate, zinc phosphate |
Advantages |
Excellent
gloss retention |
| Application
Conditions |
Electrostatic
powder spray |
|
Good
salt spray resistance |
|
40
- 100KV |
|
Wide
range of possible colors |
| Film
Thickness |
1.2
- 3.5 mils |
|
Possible
F-4H pencil hardness |
| Specific
Gravity |
1.2
- 1.8 |
|
Smooth
coatings produced |
| Coverage |
107.0-160.0
sq.ft./lb. per mil of coating |
|
Gives
low gloss matte finishes |
| Baking
Schedules |
5
minutes at 410º F |
|
|
| (Standard
Cure / |
10
minutes at 399º F |
Disadvantages |
Releases
volatiles upon curing |
| Metal
Temperature) |
15
minutes at 374º F |
|
Thick
film limitations |
|
30
minutes at 356° F |
|
|
Polyurethane 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.
|
