Corrosion measurement—as opposed to corrosion testing—more accurately describes
electrochemical corrosion testing and the fact that corrosion should also be measured
during storage stability test package corrosion examinations…
Absorption and diffusion of ions and molecules into and through a
polymer open it up, creating molecular liquid rivers through the polymer,
much like bulldozing a path through a dense forest makes it easier to
walk through it.
June 2020 SPRAY 23
ous path makes a dry polymer barrier between the underlying metal
or metal foil and your formula.
Corrosion of polymer coatings and films changes the chemical
composition of the polymer and changes the polymer’s properties,
such as its glass transition temperature and the ability to be a barrier
between the metal and your formula. Changes to the polymer
are caused by:
• Positive and negative ions adsorbing into and through the
polymer
• Water adsorbing into and diffusing through the polymer
• Absorption and diffusion of specific formula ingredients
into and through the polymer
Absorption and diffusion of ions and molecules into and
through a polymer open it up, creating molecular liquid rivers
through the polymer, much like bulldozing a path through a
dense forest makes it easier to walk through it.
I’m dividing this discussion into three parts. Part 2 will include
a discussion of why corrosion cannot be predicted without corrosion
measurements and some of the major causes or contributors
of spray package corrosion. Part 3 will finish the series with a
discussion on corrosion prevention and control, plus a summary
of all three parts.
Please visit www.pairodocspro.com for more information. Thanks
for reading and I’ll see you in July for Part 2 of this series. Spray