Product Features
The epoxy powder coating is the implementation of ISO 21809-1:2018 standard, which is the bottom design of the three-layer structure of polypropylene in buried steel-made pipe, using appropriate epoxy resin, curing agent, pigment, filler, etc., and can form a composite anticorrosion system with excellent performance with intermediate layer adhesive and outer polypropylene.
Application scope and characteristics
1.External anticorrosion of steel pipe and pipe fittings.
2.Compared with other forms of anti-corrosion, it has the characteristics of good adhesion, strong cathode disbondment, and collision and damage prevention.
3.It has the characteristics of mature process, wide application range, long anti-corrosion life, and wide operating temperature range (-20℃ ~100℃).
Method and dosage
- Coating method: Electrostatic spraying.
- Theoretical dosage: 150g / m2/ 100 μ m.
- Surface treatment: Sandblasting or Pelblasting.
- Curing instructions: Apply the powder coating on the surface of 200~220℃. When the powder coating forms a gelatinized state, the middle adhesive layer is squeezed and wound, so that the two layers are integrated into one, and then wrap the polypropylene layer, and finally form a complete three-layer coating structure.
Construction technology and repair technology references
- Remove oil, rust and other loose deposits and moisture on the surface of the steel pipe.
- Sandblasting or shot blasting to Sa2.5 level, anchor pattern depth 50~90μm, surface dust removal to near white level, pay attention to adding new and old sand evenly to make the ratio stable.
- Clean the dust and abrasives on the surface of the steel pipe.
- The salt content on the steel pipe surface should not exceed 20mg/m2.
- The treated steel pipe should be protected from moisture and secondary pollution, and should be coated within 4 hours. If it exceeds 4 hours or rust or surface pollution occurs, it should be re-treated.
- Workpiece preheating is generally controlled at 200~220°C , and must not exceed 275°C.
- Apply the powder coating on the surface of the pipe, and adjust the temperature and spraying speed according to the thickness requirement and the gelling state of the surface.
- Wrap the hot melt adhesive on the epoxy powder coating at a temperature similar to the melting point, then extrude the polypropylene surface layer and wrap it on the middle adhesive layer, and compact the three layers with a pressure roller to prevent interlayer bubble.
- Coating cooling.
- The materials used for repairing shall be compatible with the already coated pipeline anti-corrosion coating.
Qualification
Powder coating properties
|
No.
|
Properties
|
Unit
|
Requirements
|
Test method
|
|
1
|
Moisture content
|
%
|
＜0.6
|
ISO 21809-1 Annex K
|
|
2
|
Minimum glass transition temperature
|
℃
|
≥95
At least 5 above maximum pipeline design
|
ISO 21809-1 Annex D
|
|
3
|
Particle size
|
%
|
3.0 % retained on 150μm sieve；
≤0.2 % retained on 250μm sieve.
|
ISO 21809-2
|
|
4
|
Density
|
g/cm3
|
±0.05Within 20 % of the nominal value specified by the manufacturer
|
ISO 21809-1 Annex M
|
|
5
|
（205℃）
Gel time
|
s
|
±20%Within ±0.05 of the manufacturer's specified nominal value
|
ISO 21809-1 Annex J
|
Coating performance
|
No.
|
Properties
|
Unit
|
Requirements
|
Test method
|
|
1
|
Cathodic disbondment
(23℃,28d,-1.38v)
|
mm
|
≤5
|
ISO 21809-1 Annex H
|
|
2
|
Cathodic disbondment
(65℃,24h,-3.38v)
|
mm
|
≤4
|
|
3
|
Cathodic disbondment
(max 90 ℃),28d,-1.38v）
|
mm
|
≤15
|
|
4
|
（0℃，2°）Flexibility
|
——
|
No cracking
|
ISO 21809-1 Annex I
|
Safety, packaging, storage and transportation
- This product is non-toxic, non-polluting and non-flammable, but measures should be taken to prevent large amounts of inhalation during operation.
- Packing: Carton outer packing, lined with polyethylene bag, net weight 25±0.2kg.
- Storage method: Store under dry, ventilated and clean conditions below 35°C, and keep away from fire and heating. After all packages are opened for use, the unused portion must be resealed to prevent moisture absorption from the air.
- Warranty period: 12 months below 35°C.
- Transportation: Avoid direct sunlight and rain. When the temperature is higher than 35°C, corresponding cooling measures should be taken.
