Written on: February 1, 2026 by W. Stephen Tait
Hello everyone. Last year, EU 2025/24 Package Regulations (EUPR25) created paradigm shifts for plastic (polymer) packaging, going from single-use packaging to multiple-use reusable/refillable packaging (service life) with a high percent content of secondary polymer (waste plastic) in new packages (circularity).
At a first glance, it appears this regulation has no effect on metal spray packages. However, metal packages typically have polymer components, such as valve bodies and internal bags, and many of the corrosion issues with polymers are similar to those for metals. There will also be instances where products are migrated from polymer to metal packaging so they can continue to be marketed in European Union (EU) member states.
This edition of Corrosion Corner provides synopses for a small number of select sections in my white paper on the EU 2025/24 Package Regulation (EUPR25).
Packaging paradigm shifts
The main components of the paradigm shifts are increased circularity with higher concentrations of secondary raw materials (waste polymer) in new packages, and increased package service life for refillable and reusable polymer packages with higher secondary raw materials. The regulations also unify the packaging minimization regulations for reducing the weight and volume of materials in packages among EU member states.
How EUPR25 exacerbates corrosion issues
EUPR25 Articles 6, 7, 10 and 11 put more focus on polymer corrosion. Article 6 specifies what constitutes modern recyclable packaging. I use the term “modern” because archeological evidence indicates glass and metal were recycled and repurposed by the ancient Egyptians, Greeks and Romans. Awareness of modern polymer recycling began around the early 1970s and large scale, in earnest recycling began around the late 1980s; global polymer recycling was <10% from 2024 to 2025.
Polymers typically have a limited number of recycling cycles before losing their physical properties and corrosion resistance. Consequently, using secondary raw materials (recycled waste polymers) in new packages creates new technical challenges:
• Secondary polymer material (waste polymers) histories need to be determined and tracked when used in new packages (history is the number of times a given batch of waste polymer is recycled)
• Waste polymers (secondary raw materials) have degradation of physical properties from corrosion by previous products. In other words, new packages with secondary materials are pre-corroded, and might or might not perform either as long as, or the same as, new packages with no secondary materials
Article 7 mandates increases in the amount of secondary raw materials (waste polymers) up to minimum of 65% in new packages, depending on the type of polymer and its use. The technical challenges associated with Article 6 also apply to Article 7. In addition, a company’s R&D packaging engineers and scientists will need to determine:
• The properties of new packages; these should be determined as function of the percent secondary material substitution
• Which polymers cannot comply with the Article 7 minimums for secondary material substitution in new packages
• What is the maximum number secondary material use-cycles for specific products
• What types of product ingredients (e.g., formula water, contaminant water, surfactants, etc.) cause the largest degradation of secondary raw materials
Article 10 mandates polymer weight and volume reduction in packages and components—to be “reduced to the minimum necessary to ensure its functionality.” This is not a new paradigm and it has been historically motivated by shipping costs.
Corrosion has a direct impact on the physical properties of polymers, such as the glass transition temperature, strength, chemical resistance, corrosion resistance and distortion. Physical property reductions make it easier to damage packaging during shipping, deform and/or cause collapse columns of stacked packages. Thus, polymer physical property reductions could cause lost revenue from the return of damaged goods, unsalable goods damaged during storage and personal injury.
Degradation of polymer properties occurs with each exposure to a corrosive environment or a number of different corrosive environments. In some instances, each subsequent degradation can increase exponentially. Degradation thus reduces the physical limit to which package weight can be reduced, particularly when packages have high concentrations of secondary (recycled) material.
Polymer corrosion rates with each exposure are typically unknown. Consequently, corrosion testing is needed to control and minimize package and package materials failures of recyclable packages.
Article 11 became effective on Feb. 11, 2025, and it mandates reusable packaging. It has a temporary speciation that polymer packages “must be rotated without alteration as many times as possible.” However, specification will be quantified and revised by Feb. 12, 2027.
Degradation of metals & polymers by their environment
Like metals, polymer packages and components all corrode when exposed to a corrosive environment. For packaging, the various products and formulas inside packages are the corrosive environments.
Polymer corrosion rates are typically lower than metal rates, thus polymer package corrosion is rarely observed with single use packaging. However, multiple use—i.e. refillable and reusable—packaging will increase observations of package corrosion. Packaging materials that corrode include:
• Coated and uncoated metals and alloys, such as tinplate (tin coated steel), tin free steel (chromium coated steel), aluminum alloys and foils
• Various polymer coatings on aluminum and steel (e.g., epoxy, PAM, vinyl and Micoflex)
• Plastic (polymer) sheets and films used to form various packages, such as bottles
• Polymer components for both polymer and metal packages
• Laminated polymer films on metal foils, metals and metal alloys (e.g., PET, PP, Nylon-PP bilayer and vinyl)
Metal and polymer material service lifetimes are proportional to 1/corrosion rate. In other words, higher corrosion rates cause lower service lifetimes and lower corrosion rates cause higher service lifetimes. Package/component rotation numbers regulated in Article 11 should be measured with appropriate corrosion tests to determine package material service lifetimes.
Package corrosion is expensive
The July 2024 edition of Corrosion Corner discussed the potential costs of packaging corrosion based on $15M USD annual product or derivative product sales. Aerosol containers were used as the example; however, the discussion also applies to all metal, polymer and laminated metal packaging/packaging components. The various cost scenarios were:
• $15.5M to $31.2M for unexpected failures occurring during product development that delay new product or derivative product commercialization for 1–2 years
• 1–2 years of lost sales ($15.5M to $31.2M) plus >$45M for unexpected failures of commercial products
• $61M to $183M from unexpected failures of commercial products that result in product recalls, personal injury and/or wrongful death litigation.
Today’s challenges can’t be solved with yesterday’s technology
EUPR25 Article 35 requires “tests, measurements and calculations” that include the corrosion testing control for compliance with Articles 6, 7, 10 and 11. Proper corrosion test methods and protocols also minimize the occurrence of expensive, unexpected metal and polymer package corrosion failures.
Traditional corrosion storage stability tests should be conducted for at least one year to achieve a 93% correlation between test results and actual, long-term corrosion. Estimating package service lifetimes is beyond the scope of traditional storage stability tests.
The short implementation time tables in EUPR25 necessitate corrosion tests that provide more information in a shorter time (e.g., <1 year) without compromising the integrity and precision of the results.
Other package qualification tests could be either ASTM standards or their derivatives. ASTM standards are limited to particular material/environment situations and do not have a correlation between test results and actual corrosion (as stated in each standard). At present, there is not an ASTM corrosion test standard for polymer packaging. Estimating service lifetimes is also beyond the scope of these standards.
Hence, more comprehensive corrosion test technology is needed to accurately measure and predict corrosion, as well as to continue marketing packaged products in EU member states. Testing is needed:
• On all package and package component materials
• In a shorter time without compromising results
• At a high correlation between test results and actual corrosion
• To estimate (predict) package service lifetime
Corrosion tests that estimate package/component service lifetimes are necessary to comply with EUPR requirements of circularity, reusable and refillable plastic packages, and package components. Aristartec Technologies is one such comprehensive system that provides all the information on metal and polymer packaging materials corrosion for compliance with EUPR25.
Final thoughts
The EU 2025/24 Package Regulation (EUPR25) has caused paradigm-shifts from the current single use packaging paradigm. New polymer materials will be developed and qualified, and more knowledge on the corrosion mechanisms, control and prevention of polymer corrosion will be needed to continue marketing packaged goods in EU member states. Therefore, significantly more research and development (R&D) resources will be required to meet these needs in a timely manner.
Thanks for your interest and I’ll see you in May. Contact me at 608-831-2076; rustdr@pairodocspro.com or from our two websites: pairodocspro.com and aristartec.com. SPRAY
