Three Layer applications involve a thermoplastic coating applied to steel pipelines as a form of anticorrosion protection. This mechanical resistance is appropriate when the risk of particularly severe coating damages exist. The Three Layer process involved several steps. First, the pipe surface is blast cleaned to remove any external residue from the mill or storage. It is then heated and sprayed with a Fusion Bond Epoxy (FBE) primer followed by the application of an adhesive copolymer and polyolefin polymers that are wrap extruded, one over the other.

There are two types of Three Layer coating available at our facilities:

Three Layer Polyethylene (3LPE)

To improve anticorrosion performance and adhesion, an additional layer of epoxy primer is sprayed onto pipe surfaces prior to the adhesive layer and Polyethylene top layer application. Three Layer Polyethylene is suitable for service temperatures from 60°C to 80°C (85°C peaks). Typical coating thickness is from 1-2 mm to 3-5 mm.

Three Layer Polypropylene (3LPP)

If a wider service temperature range and high stiffness is required, adhesive and top layers, applied over primer layer, are based on polypropylene instead of polyethylene. Three Layer Polypropylene is suitable for service temperatures up to 135 °C (140°C peaks). Typical coating thickness is from 1-2 mm to 3-5 mm.