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Coating & Ink
Outdoor powder coating
04/06/2012 | 10:27
Nowadays, outdoor powder coating’s system using triglycidylisocyanurate (TGIC) is still widely used in Asia countries.
GREEN OUTDOOR POWDER COATING PRODUCT WITH PRIMID CURING
Nowadays, outdoor powder coating’s system using triglycidylisocyanurate (TGIC) is still widely used in Asia countries. But in fact TGIC is classified in the group of dangerous substances with Symbol T (Toxic Labeling) and is prohibited to use in some countries such as Europe and Japan. Therefore, TGIC curing will be replaced by such alternative products as Primid, PT 910 or Polyurethane .. etc but it is an enormous challenge for the powder coatings industry
Primid Curing system (hydroxy alkyl amides, or HAAs ) brings a safer option and reasonable costs but still has a relatively stable product since Primid does not have any significant effect on the glass transition temperature. The downside is that Primid is limitedly dissoluble in polyester resin systems so it is important to the powder paint manufacturers to disperse well of Primid in the pre-mix, extrusion process. Another limitation to thick paint film is the creating pin-hole on the surface due to the mobility of hydroxyl groups in the molecule Primid (high speed reaction). A further limitation is the water and moisture resistance of Primid paint system compared with TGIC paint.
Comparison between two paint films using TGIC and Primid system
Comparison between two paint films using TGIC and Primid system
|
Pigments |
White |
White |
|
Curing conditions |
400°F - 5 min. |
400°F - 5 min. |
|
Paint film thickness (mm) |
1.8 - 2.2 |
1.8 - 2.2 |
|
60° Gloss |
96 |
94 |
|
20° Gloss |
85 |
75 |
|
Impact resistant |
160/160 |
160/160 |
|
Elastic (1/8 inch Mandrel test) |
Pass |
Pass |
|
Resistant rub(50 MEK Rubs) |
Good |
Good |
|
Hardness ( Pencil Hardness) |
H |
H |
|
Salt spray (hours) |
> 1,000 |
> 1,000 |
|
Recoatable |
Good |
Good |
|
Area |
TGIC |
Primid |
PT910 |
PUR |
|
Africa |
1 |
>1 |
0 |
>1 |
|
Asia / Pacific |
21 |
8 |
0 |
6 |
|
Europe |
21 |
44 |
12 |
3 |
|
Middle East |
11 |
>1 |
0 |
>1 |
|
NorthAmerica |
29 |
4 |
0 |
15 |
|
South America |
2 |
0 |
0 |
>1 |
|
Total |
85 |
58 |
12 |
23 |
Reference Data Survey 2004 (KT Kilo tons -unit)
Reference Formula white paint system ( 95:5):
Products Weight (%)
Polyester resin ( AV 33) 608.00
Primid XL 522( EMS) 32.00
Benzoin 2.00
Flow agent 8.00
Amide wax( anti- pinholes) 10.00
TiO2( Chloride process) 340.00
1000.00
Premix: Speed at least 10 minutes, temperature 25-32C
Double screw machine module: 100-120C temperature, 600-800 rpm
Curing condition: 180C / 10-12 minutes
Conclusions
With theabove comparison, Primid powder systems could completely replace TGIC in outdoor applications with outstanding advantages ofhealth and production costs and are more widespread in areas of developing countries.
Reference Formula white paint system ( 95:5):
Products Weight (%)
Polyester resin ( AV 33) 608.00
Primid XL 522( EMS) 32.00
Benzoin 2.00
Flow agent 8.00
Amide wax( anti- pinholes) 10.00
TiO2( Chloride process) 340.00
1000.00
Premix: Speed at least 10 minutes, temperature 25-32C
Double screw machine module: 100-120C temperature, 600-800 rpm
Curing condition: 180C / 10-12 minutes
Conclusions
With theabove comparison, Primid powder systems could completely replace TGIC in outdoor applications with outstanding advantages ofhealth and production costs and are more widespread in areas of developing countries.
