BioCote® is often asked why we favour silver technology over other technologies. In some cases, such as the chemical triclosan, the answer is a simple one; it is unsafe and non-compliant. In other cases however, the reasons behind BioCote’s choice are slightly more complex. The comparison between BioCote® silver antimicrobial technology and copper/copper-based additives is a perfect example. Whilst it is true that copper, like silver, is an effective antimicrobial, there are questions surrounding the suitability of copper as an antimicrobial technology, and we thought we would put these questions to bed.
Firstly, let’s get the regulations out of the way.
Like it or not, regulations play a huge part in all of our lives, and when considering using a biocide it is no different. The classification of a metal as an antimicrobial in the European Union must follow regulations and approvals under the Biocidal Products Regulation (BPR), EU Reg No 528/2012. Rightly so, the regulations set out by the BPR play a large part in deciding which antimicrobial additives BioCote® recommend to a partner company. To find out more about what BioCote® thinks about regulations of biocides, see our informative blog post.
The BPR has categories for registered and notified biocides, called ‘Product Types’. One of the most common product types needed is Product Type 9: fibre, leather, rubber and polymerised materials. This means that in the EU, if a company wanted to incorporate a biocide into a polymer to create a product (or treated article) with antimicrobial properties, they will have to use a biocide that is registered or notified in Product Type 9.
Why is this important? Because copper, and most copper based additives, are not registered or notified to use in the most appropriate product types. This means that in the European Union, to use a copper based additive or copper in a product and make claims about its antimicrobial properties is in breach of the regulations- the BPR. The only copper based additive that is registered appropriately happens to be silver-copper zeolite- arguably the best of both worlds! This is one of the many reasons why BioCote® predominantly uses silver based additives; all of BioCote’s antimicrobial additives are registered in appropriate product type categories.
It is worth mentioning here, that in the USA copper in its pure metallic form and copper alloys are registered as biocides, allowing users to make public health claims according to the legislation, FIFRA. However, BioCote’s silver technologies are also registered, allowing BioCote® partners to use them under the Treated Article exemption to take their products to market at no extra registration cost.
One of the multiple benefits of choosing BioCote® as your antimicrobial partner is that we can assist partner companies in creating an antimicrobial product that is aesthetically consistent with their existing branding, style and product range. Some of BioCote®’s partner companies have spent thousands on developing a unique style that is instantly recognisable with their commercial identity. Crucially, the addition of BioCote® silver antimicrobial technology does not change the appearance of a product, allowing companies to remain consistent with their existing product ranges.
Copper, on the other hand, does not allow for this flexibility. Whilst it is an effective antimicrobial, it is aesthetically limiting. Regulations aside, in its pure metal form, shades of copper are the only options unless a coating is applied, which would defeat the purpose of an antimicrobial effect.
Aside from this, there is also the issue of copper oxidation. An example of this is nicely demonstrated by the Statue of Liberty. Copper reacts with the air to form a green layer as a result of oxidation, mottling the appearance. In order to retain a bright finish the surface must either be sealed with a coating, polished regularly or cleaned with a weak acid to remove the residue. This, along with other properties of pure copper, such as its relative softness and low corrosion resistance, means that there are significant technical restrictions that may affect the aesthetics of the copper product.
Again, regulations aside, the incorporation of copper additives into polymers also has negative aesthetic implications. Whilst this will not impact the copper additives antimicrobial performance, over time the incorporated copper will cause a polymer to darken in colour. What was once a bright, hygienic white will darken and dull over time, as the copper has an adverse effect on the appearance of the material. In its additive form, silver does not do this when manufactured into final products. This is yet another reason why BioCote® recommends silver.
It is also worth considering product maintenance when discussing the use of different biocides. The silver technology that BioCote® provides, once manufactured into a final material, requires no additional maintenance or care. Interestingly, the technology is that good that the material in which it is encased will likely react and degrade before the silver itself.
Copper, on the other hand, needs regular maintenance. In order to remain an effective antimicrobial, a copper protected surface must be clean of all interrupting substances. Whilst this is common sense, and also true of BioCote® silver antimicrobial technology, the copper itself tarnishes and therefore reduces its antimicrobial effect. It also has a low corrosive resistance, as mentioned briefly above. This requires a wash down with water after the use of common cleaning chemicals. Whilst this is in line with current NHS guidelines, BioCote® protected products can be found in all kinds of applications, not just healthcare- hotels, schools and offices to name but a few. To carry extra cleaning instructions is both impractical and potentially costly.
The questions surrounding copper as an antimicrobial technology are not about its effectiveness at killing microbes, but about the suitability of its application. Some of these questions are elemental at their core, whereas others are subject to regulations designed to protect consumers from the inappropriate use of chemicals. The importance of this discussion is one of choice: for specifiers, architects and consumers. There are other antimicrobials, like those supplied by BioCote®, that are both suitable for application and effective. This is proven on a daily basis by the millions of people who trust BioCote® protected products across the globe every day. In an age where we are taught to question everything, the answer can only be BioCote®.