The transition period for the Elastomer Guideline published by the Umweltbundesamt (UBA), Germany’s federal environmental agency, for assessment of elastomers in contact with drinking water, ends on 31 December 2021. Sulphur cross-linked compounds currently in use in drinking water applications can no longer be used after that time. The German rubber compounder Kraiburg based in Waldkraiburg in Bavaria has succeeded in developing compounds that can be used in elastomer solutions for drinking water applications after that date.
The Kraiburg Pure series consists of EPDM compounds with a hardness between 50 Shore A and 85 Shore A, which not only consists entirely of raw materials that will still be allowed after 2021, but also fully satisfies the mechanical requirements for compounds used in drinking water applications (based on EN 681-1).
The company has obtained test certificates in accordance with specification sheet W270. As proof of the fundamental suitability of the compounds, component testing on the company’s test plates was initiated and also completed successfully for components in drinking water applications. In addition to the German approvals for drinking water, the company also has the approvals for these compounds in accordance with WRAS (GB) and ACS (France).
Furthermore, the formulation meets the requirements of the positive list for aqueous foodstuffs according to CFR 21 § 177.2600, “Rubber Articles Intended For Repeated Use” of the US Food and Drug Administration (FDA).
In addition to safe use after expiration of the transition period on the basis of diverse European certifications, the new generation of compounds features much faster and more efficient vulcanisation characteristics than comparable products: a sufficient long flow phase followed by prompt vulcanisation.
Requirements for elastomers in drinking water applications
The Elastomer Guideline published in 2011 by the UBA, Germany’s federal environmental agency, decides which input materials can be used for the manufacture of elastomers in accordance with the principles of the European Food Safety Authority (EFSA). The guideline supersedes the KTW recommendation (Plastics in Drinking Water) Part 1.3.13, which the UBA has declared as no longer sufficient for ensuring hygienic safety and drinking water quality.
The positive list in the guideline consists of three parts:
- Part 1 contains evaluated input materials that can be used for an unlimited period.
- Part 2 lists input materials that have not yet been fully evaluated. The use of these input materials is therefore limited in time. The result is that all test certificates for products made of elastomers whose formulations contain input materials from part 2 of the positive list must be issued no later than 31/12/2021 and cannot be extended past that date.
- Part 3 contains all base polymers that are allowed.