Written on: April 1, 2022 by W. Stephen Tait
Hello, everyone. Spray packages include traditional aluminum and steel aerosol containers, bag-on-valve spray packages, aerosol containers with internal bags and multiple-use spray packages. All of these packaging types are susceptible to corrosion and are very expensive!
The cost of spray package corrosion includes the unbudgeted use of resources to:
1. Investigate package failures
2. Find alternate package components for corrosive formulas
3. Develop a corrosion inhibitor system for corrosive formulas (i.e., reformulating)
Unbudgeted use of resources typically includes personnel from Research & Development (R&D), Manufacturing, Quality Assurance (QA), Marketing, Financial, Consumer Services and so on. Higher level managers from multiple areas in a company typically also become involved when package failures occur, particularly when they occur with a commercial product.
Spray package corrosion costs also include one or more of the following:
1. Third party consulting and testing to determine the cause for corrosion
2. Lost revenue when production is suspended
3. Lost market shares
4. Loss of product and/or company reputation with customers and consumers
5. Product recall
6. Commercial litigation and/or personal injury litigation
Spray package failure is caused by product leaking, propellant leaking and partially full containers that do not spray.
Information on the corrosion costs to our industry is typically confidential and proprietary. Consequently, actual corrosion costs for our industry are unknown. However, occasionally the total estimated costs for all industries are updated in various corrosion journals. For example, the most recent update (2014) estimated total U.S. packaging corrosion costs to be approximately $5.2 billion; adjusted for 3% inflation per year would make today’s cost approximately $6.6 billion.
Financial losses from both recalls and litigation are not included in this estimate, even though they both have significant impacts on the cost of corrosion. The estimation also does not include global financial losses from package corrosion failures. In other words, the inflation-adjusted cost is probably lower than the actual annual cost.
The estimated risk of corrosion is approximately 62% when package corrosion is not tested for new products and product derivatives. Clearly, corrosion is a major concern when both the cost and the risk are considered.
While much is known about the types of spray package corrosion and how to test for them, there are still many gaps in our knowledge about what causes spray package corrosion, how to accurately predict it from test results and how to prevent and control it.
Consequently, there are 12 major corrosion questions associated with new products and derivative products:
1. How do formula ingredients interact with formula-water to cause and/or contribute to spray package corrosion?
2. Will and when will water-contaminated anhydrous formulas cause corrosion?
3. Is there a critical contaminant-water concentration for all or specific anhydrous formulas?
4. How do the different types of fragrances (e.g., citrus, vanilla, etc.) cause or contribute to the corrosivity of the different spray formula types (i.e., anhydrous, aqueous, ethanol-water, emulsions, etc.)?
5. What initiates the various types of spray package corrosion, such as vapor phase, crevice (double seams and the valve crimp area), weld (steel containers) and pitting corrosion?
6. Are there families of safe formulas that will not cause or contribute to spray package corrosion?
7. Are there specific formula ingredients to avoid in specific types of formulas?
8. What causes package corrosion to be so seemingly random?
9. What spray package types are the most corrosion-resistant to different types of formulas?
10. What is the most effective way to develop robust corrosion inhibitor systems?
11. How do we avoid surprise corrosion caused by formula composition variability and package materials variability?
12. Is there a super-package that resists corrosion by all types of formulas?
This is quite a list and by no means exhaustive. Reviewing it gives an appreciation for why spray package corrosion is always a concern and a costly occurrence, particularly when the appropriate corrosion testing was not completed prior to market introduction.
These 12 questions along with corrosion’s estimated cost to our industry both demonstrate the need for vigilance when it comes to spray package corrosion. Vigilance, of course, includes proper spray package corrosion tests to qualify the compatibility of new formulas and derivative formulas with their chosen form of spray packaging.