A new polymeric solid antimicrobial is said to be a nontoxic, environmentally sustainable means of permanent protection for plastic products and costs far less than silver-based antimicrobials. Biosafe HM-4100 from Biosafe, Inc., Pittsburgh, is a cationic quarternary ammonium salt. Until now, this type of antimicrobial was not used in plastics because it was available only in liquid form, which made it difficult to incorporate. Biosafe HM-4100 is a crystalline powder based on patented polymer technology that is thermally stable in injection molding and extrusion. It reportedly will not discolor, opacify, or leach out of a wide range of thermoplastics. Biosafe has partnered with RTP Co., Winona, Minn., to make Biosafe available in masterbatch form. Biosafe chemistry is FDA listed as a modifier for medical devices and has received EPA approval. It is said to protect plastics from staining and degradation caused by bacteria, mold, mildew, and fungi, yet does not compromise transparency in clear resins. Biosafe is effective at levels as low as 0.25% to 0.50%, whereas other antimicrobials require up to 1%. Biosafe also works faster. For example, 0.5% Biosafe in TPU suppressed E-coli bacteria in under 4 hr, while 1% of a silver-based antimicrobial took the typical 24 hr. Biosafe HM 4100 adds 25¢ to 50¢/lb of cost to a formulation while silver-based antimicrobials add 75¢ to $1.50/lb. HM-4100 is aimed at medical devices and surfaces in healthcare environments; building products such as wallboard, flooring, roofing, and decks; and human-interface components of electronic devices such as keyboards, ATM machines, and airport kiosks. (412) 770-1302 • www.biosafeinc.com
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