Antimicrobial additives will always have some kind of effect on the physical properties of a material. Often there is no discernible impact on the performance of the material and sometimes the effects may be evident but inconsequential as they have no implications for the application in which the material will be used. However, some effects can be negative, ranging from from a mildly inconvenient but rectifiable colour shift to catastrophic loss of flame retardancy.

It is surprising how frequently we are approached by customers with antimicrobial materials that have been compromised through the use of inappropriate additives. Even more concerning is how many additive suppliers are unaware of these potential issues, which can have significant consequences.

If you are using polycarbonate, it is generally because of its inherent resilience. Did you know that some antimicrobial additives can reduce the impact strength by over 80%?

Silicone is notoriously sensitive to silver based antimicrobial additives, resulting in discolouration. This can manifest quickly, during moulding or extrusion, but it will often develop over time… sometimes weeks or months. We have even seen this long term silicone discolouration being noted in marketing literature as evidence that the antimicrobial is working! In fact, the opposite is probably true. Discolouration is more likely to lead to diminished efficacy as the silver has compounded with the incompatible components of the silicone and is therefore no longer available to perform as an antimicrobial.

Perhaps the most significant issue is the effect on flame retardants. When a silver based antimicrobial additive is used in a V0 rated ABS the resultant material will very probably be neither antimicrobial nor flame retardant. Depending on the application, this could obviously be catastrophic.

The good news is that all these problems can be solved.

When evaluating any new material, we not only consider the antimicrobial performance, but also the essential properties of the material, including impact strength, tensile strength, UV stability, chemical resistance, flame retardancy, colour and clarity. Our in-house capabilities and expertise enable us to run comparative tests to ensure your materials are not compromised by our additives.

If you would like to learn more or if you have any concerns over the performance of your current antimicrobial solution, our experts would be very happy to talk to you…