There is an occasional phenomenon that came be seen with PVC liners, in particular, with lower grade formulations of PVC.  This phenomenon is what can be best described as a shedding of the liner.  Very thin sheets of PVC come off the liner and enter into the solution.  On their own, they aren’t an issue, but they can interfere with the process work in the tank.

Two common elements are in place with this phenomenon.  The first is the solution has some sort of chrome base to it.  It could be hard chrome, decorative chrome, or even a dichromate.  The second is oxygen, usually in the form of air agitation.  These two factors can cause the chrome to penetrate the liner and more or less oxidize the surface plasticizers.  The result is the liner beings to shed this layer of material into the solution.  Typically, this shows itself in the first 90 to 180 days of service.  The amount of material coming of the liner does reach a  high point then seems to subside.  No appreciable loss of service life is seen but there is the issue of interfering with the process work while this issue is ongoing.

Higher quality formulations of PVC, like our Koroseal PVC, do not exhibit much, if any, surface plasticizer.  As a result, this shedding phenomenon hasn’t been seen with these formulations of PVC.  Another example of when “cheaper doesn’t mean less expensive”.

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