Mechanical & Chemical

Chemical

Every powder coating system, polyester, epoxy, acrylic, etc, will have its own intrinsic resistance to chemical attack.  A coating's resistance to chemicals can be tested in a number of ways, most usually by prolonged exposure, either a spot test or by partial submersion in the liquid chemical.

Softening

The film has poor resistance to a chemical, such as a solvent, an acid or alkali, a detergent or a chemical in gaseous form. The poor resistance may be apparent as a change in gloss or colour; may be a softening or degradation of the coating; or may be blistering and delamination from the substrate.

  • Potential Cause

    Powder coating chemistries have differing chemical resistance properties.  The coating being used is not appropriate to the environment.

  • Solution

    Consider what aggressive chemicals the coating needs to withstand.  If in doubt, discuss your requirements with us.  We’ll carry out a chemical resistance test specific to your requirements.  Many powder coatings can be custom-made to maximise resistance to certain chemicals.

  • Potential Cause

    Under-curing of the coating.  The chemical resistance of a coating is one of the last attributes to develop in the cure cycle.  Often near-full cured films will show adequate or good adhesion, so that the coating appears to be fully cured, whereas the chemical resistance has not been fully developed.

  • Solution

    A full cure is required to realise the coating’s potential.  Modify cure conditions by increasing temperature and dwell time.

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