ADDITIVES | ANTIMICROBIALS
Right: This water treatment system from Pentair uses Sciessent’s Agion antimicrobial in its filters
the other, of “scaring people to be as hygienic as possible.” To counter these messages, Morris co-authored a white paper published in October 2018 by the International Scientific Forum on Home Hygiene to promote the risk- management approach of targeted hygiene. “[It] provides solid scientific advice on when extra help (biocides) are required, such as food preparation areas, and we also tackled the misinformed scare stories about hygiene,” he explains.
Medical applications Use of antimicrobials in medical devices entails considerable regulatory hurdles and additional requirements for proving safety and efficacy, but suppliers of silver-based antimicrobials have been supporting these uses for years. “Silver continues to be a very good option and has proven itself in the healthcare space, which has the highest safety demands and efficacy requirements,” says Sciessent’s Lise Moloney. Earlier this year, Netherlands-based Parx
Plastics, which supplies concentrates for various polymer types in a range of applications using its patented antimicrobial technology based on elemental zinc, established a joint venture in Belgium under the name Zinkh NV to develop antimicrobial technology in dental applications. One example is a prevention tray under development to reduce bacteria build-up in the mouth overnight. Michael van der Jagt, CEO at Parx Plastics, says: “The trace element of zinc is an essential element for the human health and the human immune system. … Zinc is also a known component helping to prevent plaque build-up on teeth.” He says in-vivo trials have shown promising results and an initial product will launch soon. Regulations governing biocides in plastics and
restrictions on different types of active ingredients vary by geographical region. In the US, biocides
Right: The casing for this Thermapen food-preparation thermometer contains Biomaster antimicrobial additives
are regulated by the EPA, which has a programme for reviewing registered active ingredients. In the EU, biocides are regulated under the Biocidal Products Regulation (BPR) and all active ingredients must go through the BPR’s review programme for approval. The differences in US and EU regulations lead to different ingredients being used in the two regions. In the US, OBPA (10,10’-oxybisphenoxarsine) use continues to grow, says Helena Kim, Business Manager Plastics at Troy Corporation, which is the sole supplier of OBPA in North America. She says OBPA remains the most effective biocide for flexible PVC applications due to its broad-spectrum capabilities in resisting fungi, bacteria, and pink staining caused by actinomycetes. The company has invested significant resources in the testing required by the US EPA for federal re-registration of OBPA, and testing should be completed by the end of 2019, she says.
PHOTO: ADDMASTER
Regulatory challenges In the EU, meanwhile, suppliers did not support notification of OBPA in 2013 but Troy is currently evaluating the feasibility of including OBPA in the BPR review programme. “OBPA was never at any point banned in the EU. Quite simply, OBPA was listed under the old EU BPD and supplied successfully and safely for many years. But once the new EU BPR took effect in 2013, OBPA, alongside other biocide molecules, was not carried forward by other suppliers or listed under the new Review Programme. As a result, its permitted use simply ended,” Kim says. Isothiazolinones, which are an alternative to OBPA for use in PVC, also face restricted use in multiple regions. The EU BPR has restricted OIT and DCOIT in paints and coatings to 15ppm due to sensitisation precautions, and these restrictions are expected to be extended to plastics uses by 2021, says Kim.
20 COMPOUNDING WORLD | July 2019
www.compoundingworld.com
PHOTO: SCIESSENT
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