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Clariant Masterbatches with CESA® Antimicrobial Fight Odor in Footwear

Muttenz, April 4, 2014 - Clariant, a world leader in specialty chemicals, today announced availability of CESA®-antimicro additive in masterbatches with demonstrated protection against odor-causing bacteria in shoes, boots, sandles and other footwear made with polymeric insoles.

"Footwear poses a special challenge when it comes to preventing the development of odor-causing microbes," explains Brett Watkins, Product Manager – Clariant Additive Masterbatches. "The pressure and rubbing of feet against the soles and interior surfaces of shoes and sandles reduces effectiveness of the most common antimicrobial treatment – Silane quaternary amine (Si-quat) antimicrobials. Silver ion technology, which is the other commonly used antimicrobial, is effective only at high dosages which are cost-prohibitive in many footwear applications."

Si-quat antimicrobials, Watkins explains, bond chemically when applied to a surface and transform it into a microbial barrier by creating microscopic "spears" that destroy micro-organisms like mold, mildew and odor-causing bacteria as they come into contact with the surface. When Si-quats are used in shoes, however, the "spears" are broken by the pressure and rubbing of the wearer’s feet and may reduce the effectof preventing microbial growth. CESA-Antimicro additive masterbatches from Clariant Masterbatches, on the other hand, are based on organo-metallic materials that are blended into the polymer during processing, anchoring them on the surface where they depolarize the microbe membranes and deactivate the microbe. Rubbing the surface does not diminish effectiveness of CESA-Antimicro.

CESA-antimicro masterbatches are more effective at controlling certain odor-causing bacteria like Trichophyton mentagrophytes when compared to silver based products. Against other odor-causing bacteria, such as those in the Klebsiella genus, the two technologies are both effective but the CESA-antimicro is more cost-effective. This is because the silver-ion additives must be used at much higher concentrations – as much as ten times higher – than the organo-metallic additive used in the Clariant antimicrobial masterbatches.

Subjective testing, involving a panel of human reviewers, was conducted over a period of six months by a major footwear manufacturer. Test subjects wore footwear treated with either quat silanes, silver ion compounds or the organo-metallic CESA-antimicro product. Every four weeks, the panel of odor testers smelled and rated the odor left on the footwear. They reported that the footwear containing Clariant product evidenced less odor than either of the other treatments.


Masterbatches are pelletized materials that incorporate high concentrations of an additive (or colorant, or both), evenly dispersed in a plastic material called a carrier resin. During processing masterbatch pellets are added to natural (untreated) resin to produce a finished product with the characteristics created by the additive, in this case a registered antimicrobial. Unlike Si-quat and silver ion antimicrobials, masterbatches containing CESA-antimicro are easier to use and safer to store than the base antimicrobial material as Clariant has already encapsulated the antimicrobial into the resin.

Even compared to other masterbatches that use similar antimicrobial chemistries, Clariant CESA-antimicro is expected to perform better because it can be specifically tailored to the customers process and materials. "Most competitive masterbatches are based on resins like polyethylene or ethylene vinyl acetate" explains Brett Watkins. "Depending on the application, these ‘universal’ carriers can cause issues for the processor and affect the development of critical performance properties. Clariant’s carriers are tailored to the customer’s application for superior performance. They can even include specialized dispersion packages when required."

CESA-antimicro masterbatches include additives which can extend antimicrobial options to many different plastic products. Beyond footwear, typical applications for antimicrobial masterbatches include fibers and textiles used in athletic gear and household furnishings, kitchenware and bathroom products, automotive steering wheels and interior parts, and a broad range of other plastic applications requiring a high standard of antimicrobial protection. Clariant has a long-established collaboration with Sanitized AG, a Swiss company offering antimicrobial additives for a range of uses.


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