12 January 2022
Blog
Building the foundations for chrome free passivation
Packaging steel coils

The agreed European alternative for 311 or 300 passivation of electrolytic tinplate (or ETP) is CFPA.

Built with the aim of ensuring the protection of both human health and the environment, ‘REACH’ stands for Registration, Evaluation, Authorisation and Restriction of Chemicals and is a wide-ranging European Union regulation guiding and governing the use of chemicals. 

One of the systems created within the REACH framework is the identification of Substances of Very High Concern (SVHC) and the resulting risk management options to control the use of this class of substances and ensure safe use. 

‘Authorisation’ is one of the REACH control processes which stipulates that companies must effectively apply to the European Commission for authorisation to continue using a SVHC for a limited period, until a replacement has been approved.   

Hexavalent chrome, which is commonly used in applications across the automotive, aerospace and defence industry, is also found in the manufacture of tinplate, has now been classified as an SVHC and placed on the Authorisation list. 

Consequently, this substance needs to be replaced. For many canmakers moving forward, one concern may be the availability of a REACH compliant tinplate. 

The original product

Chromium passivation (also known as 300 or 311 passivation) involves the use of hexavalent chromium in a chemical or electrochemical treatment to the surface of tinplate. 

The main functions of the passivation are:
-    to inhibit the growth of tin oxide on the surface; 
-    to ensure the surface is amendable to subsequent lacquering and decorative printing; 
-    to minimise sulphide staining by foodstuffs.

During this surface treatment all hexavalent chrome is converted to trivalent chrome or chrome metal. 

There is no hexavalent chrome on the surface of the final tinplate product or steel cans.

We supply a wide range of proven tinplate products for applications
Setting the standard for chrome-free passivation 

Because hexavalent chrome has been classified as an SVHC and was placed on the REACH Authorisation list, any company now using the substance needs to apply to the European Commission to be allowed to continue doing so. If granted, this provides the applicant with a time limited period to develop less hazardous alternatives with all members of their supply chain.

Members of the Association of European Producers of Steel for Packaging (APEAL), which includes Tata Steel have been working together on a solution also known as Chrome Free Passivation Alternative - CFPA. 

CFPA testing and compliance  

APEAL members have actively pursued a hexavalent chrome replacement without compromising on product safety or food contact suitability and have been leading members of the International Tin Association (ITA) Chrome Free Project since 2006, when REACH legislation was launched. 

The agreed European alternative for 311 or 300 passivation of electrolytic tinplate (or ETP) is CFPA. Edward Span is Chair of APEAL’s CFPA R&D Working Group:

“In order to ensure that all industry members can produce the equivalent standard of CFPA material, we have pooled knowledge and shared resources. As with all research and development, some issues have arisen, but APEAL members have invested heavily in overcoming these.”
“We found that there was some variability in the quality of CFPA being produced by different APEAL mills and this could affect the application of dry adhesion lacquers. We shared sample materials and developed a set of experiments to identify the root cause to ensure standardisation of manufacture. 
“Between APEAL members’ technical experts, we’ve been able to reduce the level of variability to an acceptable level that is equivalent to the variability found in the current 300 and 311 products.” 

CFPA is already compliant with food contact legislation in Europe and China; it has obtained a Food and Drug Association notification for food contact and dry infant formula in the USA; and compliance with Brazil’s legislation is in progress. CFPA will also be included in the revised Euronorm, which will be published in 2022.

The future for CFPA 

Today APEAL works with other industry bodies including Metal Packaging Europe to ensure a smooth transition to CFPA across the supply chain. Canmakers already have many pack tests on-going with CFPA for multiple applications. 

The industry has authorisation with the European Commission until 2024 and Tata Steel has requested an extension until December 2027 to ensure a smooth transition to CFPA.

With teamwork and collaboration, CFPA will be a mainstream material. And as Edward rightly states:

“All APEAL members are fully aligned and committed to the successful implementation of CFPA, and we continue to work hard, in conjunction with our supply chains, towards its timely approval and implementation.”

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