The issues are whether the rate of the inevitable corrosion of RMu packaging
materials is low enough so that packages will have the desired service life and if
the concentration of metal ions from corrosion is low enough to not adversely
June 2019 SPRAY 27
affect product performance and efficacy…
accumulated and grew until finally the last bump was enough to
cause the mug to fail.
Internal polymer coatings in aluminum packages also develop
memories each time they are subjected to different chemicals,
such as the detergents used for cleaning with water in combination
with high temperatures. Polymer memory could lead to
increasing degradation of a coating’s or film’s barrier properties,
fracture of the polymer coating/film and delamination of the
coating or film from the metal, such as blistering.
Denting
Metal denting is cosmetic and does not lead to metal package
failure. A lot of force is typically needed to dent metals, so they
are essentially dent-resistant. This statement gains credence from
the fact that around 300-plus billion aerosol, food and beverage
containers are used globally each year with a minimum number
of dented packages. Resistance to cosmetic metal denting can be
increased by using harder metals such as steel and stainless steel
alloys and using thicker metals for the RMu packages.
All three of the RMu packaging materials (coated aluminum,
glass and stainless steel) will corrode. The issue with corrosion
is whether the corrosion rate is low enough so that the packages
will have the desired service life and if the concentration of metal
ions from corrosion is low enough to not adversely affect product
performance and efficacy. We’ll continue the discussion of RMu
packaging in the July issue.
Please visit www.pairodocspro.com for more information. Thanks
for reading and we will see you in July. Spray