Hybrid coatings share many characteristics
with standard epoxy-based powder coatings. The primary
differences are improved resistance to overbake yellowing
during cure, somewhat softer films, and slightly improved
weatherability. Like epoxies, hybrid coatings are not
considered suitable for exterior applications, even though
their deterioration and discoloration when exposed to sunlight
is slower then pure epoxies. Hybrid coatings have similar
characteristics associated with polyester formulations in
terms of impact and bend resistance.
Hybrid coatings are often used in the same
applications as epoxies particularly when slight improvement
in weathering and overbake stability is required. Typical
applications are shelving, hot water heaters, office furniture,
power tools, tool boxes, electrical boxes, fire extinguishers,
underhood automotive and oil filters.
| Pretreatment |
Iron
phosphate, zinc phosphate |
Advantages |
Good
adhesion |
| Application
Conditions |
Electrostatic
powder spray |
|
High
resistance to yellowing |
|
40
- 120KV |
|
Minimal
volatiles given off
during cure |
| Film
Thickness |
1.5
- 20.0 mils |
|
Excellent
transfer efficiency
and wrap around properties |
| Specific
Gravity |
1.2
- 1.8 |
|
Suitable
for primers |
| Coverage |
107.0-160.0
sq ft/lb. per mil of coating |
|
Good
boiling water resistance |
| Baking
Schedules |
5
minutes at 399º F |
|
Good
intercoat adhesion |
| (Standard
Cure / |
10
minutes at 375º F |
|
Less
sensitive to substrates |
| Metal
Temperature) |
15
minutes at 347º F |
|
Good
mechanical properties |
|
|
|
Good
salt spray resistance |
|
|
Disadvantages |
Poor
UV resistance |
|
|
|
Softer
films than epoxies |
Hybrid 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.
|
