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Many applications will potentially benefit from the use of antimicrobial silicone to reduce the growth of bacteria and mould.
The use of antimicrobial additives in silicone and rubber is a relatively straightforward process although there are potential issues for which we can provide guidance.
We have a range of additives suitable for all types of silicone, including LSR, HTV & RTV. The additives are available as powder, paste or solid silicone masterbatch.
With two Z-blade mixers and a roll mill, producing bulk dough masterbatches and compounds is easy. When necessary, we can run compatibility trials, manufacture a sample masterbatch or compound and produce cured test pieces on the same day we receive a sample of your silicone. Antimicrobial testing can then conducted at an independent laboratory and results are typically available within one week.
One of the most important considerations with silicone is compatibility of the antimicrobial additive with the silicone catalyst. Incompatibilities will generally manifest as discolouration, but this can take some time to become apparent in the moulded product. An accelerated compatibility test will usually confirm any likely colour instability, as illustrated below.
Another consideration is the potential interaction of pigments with the antimicrobial additive. This is relatively uncommon, but some pigments can adversely affect the antimicrobial performance. For this reason, it is important to conduct antimicrobial testing on each colour variant.
It is generally also recommended to test for changes in critical chemical & physical properties such as Young’s modulus or tensile strength, for each individual application system, as well as the effects of external factors such as pH, moisture, temperature and UV light.
Some antimicrobial additives can have a notable detrimental effect on the properties of the materials in which they are used, but our silicone additives have been formulated to eliminate such issues.
The SteriTouch mark is available to anyone using our products, subject to a Trademark Agreement. There are no licensing fees or annual commitments for any of our customers using the mark.
Generally, no problem at all, but it is always a good idea to do a quick compatibility check.
The active substances we use all have EFSA and FDA approval. Other components are typically either food contact approved or GRAS. It is important to understand the regulatory requirements for food contact applications though, and we will gladly advise.
The additives themselves are very heat stable… beyond the normal manufacturing or usage range of most silicone products. That being said, high temperatures can catalyse reactions that might otherwise not occur, so if your application is particularly demanding, we would be happy to provide guidance and if necessary formulate a custom additive.
Addmaster Ltd (Polygiene Group)
Darfin House, Priestly Court, Staffordshire Technology Park, Stafford, ST18 0AR, United Kingdom
damian.harvey@addmaster.co.uk
