Corrosion by Formula & Package Factors: Part 2

Happy New Year, everyone. In the December 2021 issue of SPRAY, I discussed the most common formula factors that affect spray package corrosion. In this issue, we’ll complete the discussion with the most common package factors that affect spray package corrosion: 1. Type of package (e.g., aerosol containers and bag-on-valve) 2. Type of internal package […]

Corrosion by Formula & Package Factors: Part 1

Package corrosion is a complex interaction between a large number of formula and package factors. It has been my experience that there are at least 16 known corrosion-contributing and/or corrosion-causing factors for spray packaging. These factors can be grouped into formula and package subcategories as follows: 1. Formula factors Ingredients • Propellant type • Fragrances […]

Why not worst-case corrosion tests?

Hello, everyone. Supply shortages, changing market demographics and faster-to-market pressures tend to make formula chemical compositions change and evolve over time. These pressures often make worst-case corrosion tests seem attractive for new products and derivative products (line extensions) in particular. The reasoning for worst-case corrosion testing is often that a product that passes a worst-case […]

Spray package material defects: Part 3

Hello, everyone. This month we continue a series that began in June concerning spray packaging material defects and their relationship with corrosion. Corrosion Corner in June and July covered defects in polymer and tinplate coatings, laminated film bags and the metals used for traditional aluminum and steel aerosol containers. Most of these material defects are […]

Spray package material defects: Part 2

Hello, everyone. Last month, I began a series on material defects in spray packaging and the relationship between these defects and corrosion. We completed a discussion on the more common defects in aluminum aerosol containers. This month, I will discuss the more common material defects found in laminated foil bags and tinplated steel aerosol containers. […]

Spray package material defects: Part I

Hello, everyone. There is no such thing as defect-free spray package materials. Thus, there are always potential concerns as to whether or not defects will contribute to or cause spray package corrosion, and if corrosion at these defects will cause spray packages to fail (leak). This issue starts a three-part discussion on material defects and […]

Statistical analysis for spray package tests

Hello, everyone. In many instances, spray packages are qualified for commercial markets with a variety of tests, such consumer preference and corrosion tests. The statistical average (statistical mean) for each data-group is often used to compare the results between different groups of test variables. However, statistical means hide extreme values that are important for decisions […]

How does corrosion start in spray packages?

Hello everyone. I’m often asked how spray packaging corrosion begins. There are multiple types of corrosion and each begins differently. Consequently, a comprehensive and often nuanced discussion on how corrosion begins is beyond Corrosion Corner’s scope. However, I’ll do my best to provide a succinct overview on how spray package corrosion begins. Corrosion Basics: Spray […]

Emulsions & Spray Package Corrosion

Hello, Everyone. There are times when one or more formula ingredients are not soluble in the rest of the formula. In these instances, the insoluble ingredients are dissolved in another solvent before mixing with the main formula. However, what happens when the solvent for the insoluble formula ingredient(s) is also insoluble in the main formula […]

Corrosion testing Dos & Don’ts…

Hello, everyone. In some instances, the COVID-19 pandemic has caused delays of new product and derivative product R&D programs. Consequently, it might be tempting to take shortcuts with corrosion tests to meet compressed timetables when programs are restarted. However, taking shortcuts with corrosion/stability testing could have unexpected and unwanted results for both completely new and […]