ADDITIVES | ANTIMICROBIALS
now been extended to 31 December 2030. Some silver-based antimicrobials have been
under review. It is important to note that there are many types of systems that release silver or other ions, and these are all considered separately by regulators. “The good news is a silver-based system, similar
to that used in [Wells’] BACTIglas range of products, has gained EU BPR approval product types 2, 7 and 9,” says Simmons. “This illustrates that silver-based systems can achieve approval, which is encouraging for those systems still waiting to be reviewed. The final approval text and possible restrictions for the system approved this year will not be completely analogous for other silver systems, as it releases another ion not just silver. These differences in action and structure are why the different systems are being reviewed individually.”
Natural chemicals In the UK, the Health and Safety Executive (HSE) has said that under the GB BPR, products contain- ing existing active substances can remain on the GB market while they are being evaluated under the review programme, Simmons reports. “A GB Article 95 List has been established which clearly identifies the active substances notified to the HSE, the status of these substances and if they are permitted. Currently there is no timetable or work plan provided by the HSE outlining the timescales for completion of the review of active substances,” she says.
While natural active substances have seen
attention recently, there is no standard definition of what is “natural”. “It is important to note that EU and GB BPR do not make a distinction between natural and synthetic biocides; the substances are still chemicals and are treated the same under the regulations,” cautions Simmons. In a related trend, bio-based materials with
biodegradable or compostable properties are also seeing increased attention. As these materials are intended to act as a food sources for microbes, they could support microbial growth. “Antimicrobials could find a use in compostable
Test Product details PCR PP (Untreated) PCR PP (Treated with BioCote) Source: BioCote 36 COMPOUNDING WORLD | July 2024
bacteria MRSA E. coli MRSA E. coli
Reduction
against Initial -671.86% -1242.15% 99.85% 99.88%
polymers to reduce microbial growth on a prod- uct’s surface during its use lifetime,” says Simmons. “As compostability depends upon the action of microorganisms, adding an antimicrobial that could interfere with this activity seems counterintui- tive. In reality, the composting environment would be so microbially rich that the presence of a relatively low amount of antimicrobial would have limited effect [on compostability].”
Elemental silver While some silver-based substances are expected to be removed from the EU market, HeiQ is promoting elemental silver as a solution for plastics that is anticipated to remain on the market for the foresee- able future, says Tom Ellefsen, Head of Business Unit Antimicrobials at HeiQ. In 2023, the company acquired Tarn-Pure’s elemental silver technology that has EU BPR registration, as well as F Group Nano’s EPA-registered silver biocidal technology. HeiQ supplies a broad range of elemental silver- based additives: powders, liquid dispersions of powders, and pelletised masterbatches. HeiQ is also expanding its antimicrobial master-
batch offerings and has launched a next-generation range of silver-based antimicrobial masterbatches under the HeiQ HyProTecht brand. “These deliver excellent transparency in clear polymers, such as GPPS, PC and PET, at less than half the cost of competing masterbatches,” says Ellefsen. The masterbatches are compliant with EU BPR and US biocide regulations, as well as compliant with food-contact plastic regulations in China, the EU and US. The masterbatches are available in all commonly used polymeric carriers, including PE, PP, PS, ABS, PA, PET and PC, Ellefsen says. The latest from HeiQ is a range of fast-acting
silver-based antimicrobial masterbatches that deliver robust efficacy in ISO 7581 testing for EU BPR Product Type 2 applications (antimicrobials incorporated into articles or materials with the purpose of producing treated articles with disin- fecting properties). Ellefsen says: “Conventionally used test methods, such as ISO 22196, measure bacterial reductions over a contact time of 24 hours, and are not suitable for use in BPR Product Type 2 applications. The new test method ISO 7581 has been developed to address this deficiency: it reports bacterial reduction over 1-2 hours of contact time, as well as dry test conditions, which makes the testing even more challenging.” BioCote says that its silver glass technology is
currently under EU review and is permitted for use in biocidal applications with the approved product types under the EU BPR. The technology is viewed
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