Corrosive formula ingredients adsorb on surfaces, absorb into the polymers,
diffuse through polymers and remove electrons from both uncoated
and coated surface metal atoms (i.e., corrosion).
February 2018 SPRAY 27
Internal coatings & laminate films
Uncoated metals are the least expensive form of spray package
materials. However, in some instances an internal coating either
prevents or extends the service life of a metal package to an
acceptable level. Corrosion testing selects the most corrosion-resistant
form of coating or laminate film for a spray package-formula
combination.
Corrosion inhibitors
Corrosive formulas do not have to be abandoned. Corrosion
inhibitors are an effective way to control or prevent spray package
corrosion, although their inhibitor development often extends a
development timetable. However, corrosion inhibited formulas
are often patentable and thus provide a market advantage. Corrosion
testing is used to select the most effective corrosion inhibitor
and determine its effective concentration range.
Experience & Knowledge
Knowledge without practical experience or experience without
theoretical frameworks are incomplete and will not result in useful,
predictive professional practice. In other words, experience
and knowledge are intricately linked.
Extensive corrosion databases for spray packaging are unavailable
in the public domain because of market competition. Consequently,
proprietary corrosion databases are typically developed
by individual companies only for internal use. A proprietary
database a) allows faster-to-market introduction of new and derivative
products; b) provides formulation guidelines for avoiding
developing corrosive formulas; c) reduces corrosion risk during
product and derivative development; and d) reduces the corrosion
risk of commercial products.
Pair O Docs has a state-of-the art electrochemical corrosion
testing laboratory; please contact me if you would like to know
more about our rapid, predictive corrosion testing. You can
also visit our new website which has a short Vision Video that
discusses all our corrosion prevention and control services.
Please also contact me if you would like to a have our Elements
of Spray Package Corrosion short course taught at your R&D facility.
Back issues of Corrosion Corner are available on CD-Rom.
Thanks for reading and I’ll see you in March. SPRAY