Pre-Treatment Plant


Pre-Treatment Process:

Pretreatment is the base for powder coating. It is said that you cannot make a good coating work with poor pretreatment. Hence utmost care should be taken to ensure proper pretreatment is applied before powder coating. Proper pretreatment means the application of the right process and proper maintenance of the chemicals.

There are two main categories of powder coating: thermosets and thermoplastics. The thermosetting variety incorporates a cross-linker into the formulation. When the powder is baked, it reacts with other chemical groups in the powder to polymerize, improving the performance properties. The thermoplastic variety does not undergo any additional actions during the baking process as it flows to form the final coating.

The most common polymers used are polyester, polyurethane, polyester-epoxy (known as hybrid), straight epoxy (fusion bonded epoxy) and acrylics.

The Powder Coating process:

The powder coating process involves three basic steps:

  1. Part preparation or the pre-treatment
  2. The powder application
  3. Curing

Sequential Process of Pre-Treatment:

  1. Digressing Bath
  2. Water Rinsing
  3. De-rusting
  4. Water Rinsing
  5. Phosphating
  6. Water Rinsing
  7. Hot Phosphating