Epoxy Resin 520 / Hardner 269 is low viscosity solvent free epoxy coating system used for heavy duty corrosion protection. This system can be applied in chemical industries like Fertilisers, Paper, Textiles, food industries, ships, pipes, water treatment plants, sewage drains, etc.
System involves careful surface preparations, application of primer coat and top coats with appropriate & proper curing.
The system consists of the following operations :
Surface Preparation
- Mild Steel Surface
- Thorough sand blasting to ensure complete removal of rust particles
- Surface should be free from grease , oil or moisture
- Degreasing with non flammable solvents like trichloroethylene or carbon tetra chloride
- Hot air blast to remove traces of solvent or moisture
- Concrete Surface
- Concrete surface should be freed from laitence and dust by sand blasting
- Thorough abrading with hard wire brush
- Chemical etching using 15% hydrochloric acid solution should be employed. The solution is applied by brush over the surface liberally and left in contact for 15 minutes. This is then washed off with plenty of water followed by drying with hot air
For good adhesion, cleanliness, roughness and dryness of the surface are essential. Unless these are ensured by proper surface preparation a successful performance is not possible.
Method Of Application
- Primer Coat
- One brush coat of the following system is recommended as a primer on the pretreated surface .
- Epoxy Resin 520 - 100 p b w
- Hardner 140 - 50 p b w
- Hardener 140 is a polyamide type hardener and facilliates thorough surface contact and tie up with the subsequent coats. The primer should be allowed to be just tack free prior to the application of top coats. The primer must not be fully cured, since adhesion with a cured epoxy system is very difficult
- Alternatively you may try
- Epoxy Resin 520 : 100 parts by weight
- Hardner 269 : 60 parts by weight
- Flow control agent 2 to 5 parts be weight
- Above system is also used us a primer coat
- Top Coats
- Two top coats of the following system are normally adequate for a protective treatment :
- Epoxy Resin 520 : 100 p b w
- Hardner 269 : 60 p b w
- Silica Floor : 20 p b w
- Flow control agent : 2 p b
- The first coat is applied over the primer coat and is left to reach a tack free state. At this stage, the final top coat is applied. The use of silica floor increases the abrasion resistance of the coating. Flow control agent ensures proper spreading of the system without any surface defects like cratering or fish eyes.
Curing
- Complete curing of the system takes place at RT (25 – 30°C) in seven days
Coverage
- The area covered by the coatings depends among others upon the temperatures of application and roughness of the surface. One kg of the unfilled resin and hardener systems covers 3 – 4 m2 per coat when the coating thickness is approximately 150 – 170 microns on plain surface.
Chemical Resistance
- Water : Excellent
- Alkalis (Any Concentration) : Excellent
- Acids (Inorganic) : Good
- Acids (Organic) : Good
- Solvent : Good