Evaluation of two Anti-Crobe acetals using the Efficacy Test Method JIS Z 2801 for microbe proliferation showed they greatly inhibited microbial growth compared to conventional acetal. The tests indicate that Anti-Crobe AM90S Plus is suitable for rapid bacterial control, while Anti-Crobe AM90S is appropriate in less-demanding situations.

Materials that restrict the growth of microorganisms on equipment and surfaces in the medical environment help control the potential for infection in hospitals, clinics, and doctor's offices. The latest such material is a family of acetal copolymers from Ticona called Anti-Crobe Antimicrobial Polymers. These engineering plastics give medical designers a tool to apply to demanding applications that can benefit from resistance to bacteria and fungi. The material works by inhibiting bacteria's ability to reproduce.

The inorganic, antimicrobial technology built into this acetal series is present throughout the polymer matrix and not just on the surface as with coatings. This means its protection won't abrade or scratch off, so it can continue to limit microbial growth over the long term. This deterrent to bacteria and fungi also keeps them from attacking the plastic and causing the odors, stains, biofilms, and loss in mechanical properties that can compromise product performance.

The Anti-Crobe line features injection molding and extrusion grades and two levels of antimicrobial action. The grade with the highest efficacy, Anti-Crobe AM90 Plus, provides a log 4 or 10^-4 reduction in bacterial replication after 4 to 5 hours. Anti-Crobe AM90 provides a similar reduction in 24 hr. These values were measured by the Efficacy Test Method: JIS Z 2801 Quantitative Test, in which bacteria are placed on a sample, covered with a plastic film and held at 35C for 24 hrs. The number of viable bacteria is then counted. The material has been effective against bacteria, algae, and some molds.

The two grades were also compared against a standard acetal lacking the antimicrobial agent. After six hours, it was clear that the Anti-Crobe acetals greatly inhibited microbial proliferation compared to the conventional grade. These evaluations indicate that Anti-Crobe AM90S Plus may be suitable for applications requiring rapid bacterial control when time is of the essence and high efficacy and quick retardation of bacteria is needed, while the other is appropriate in less-demanding applications.

Many components and surfaces touched by medical staffs or patients are candidates for these new antimicrobial grades, as are hard-to-reach-and-clean areas that can foster microbial growth. The polymers' high lubricity also makes them ideal for sliding parts, such as those in hospital beds.

The materials are dimensionally stable, abrasion resistant, and tolerate of low temperatures. In addition, they give good surface esthetics in molding. And as a naturally white polymer, they can be tinted or color coded. They also have a high resistance to chemicals and withstand continuous exposure to hot water at 82C (180F) and intermittent exposure to water at 100C (212F) or more. They can be sterilized by all common chemical, thermal, and irradiative sterilization methods.

The polymers were developed for use where polyolefins and other commodity plastics cannot meet performance specifications. Of course, the polymers do not protect users or others against disease-causing or food-borne bacteria. Antimicrobial properties apply only to the molded part. No public health claims are made regarding these resins, which have antimicrobial additives, or the products that contain such resins.

A few physical properties for the new acetals