Spectrum of activity against microorganisms

The biocide must be both physically and chemically compatible with the polymer formulation. Most biocides work only at the surface of the plastic. For the biocide to be effective, it should be able to distribute within the plastic. The biocide must have sufficient solubility in the polymer matrix so that it can diffuse within the polymer to come to the surface, but not bloom at the surface. Blooming will result in premature loss of biological activity and possibly give rise to unacceptable risk of human and environmental exposure at the surface of the plastic article. Biocides that are chemically incompatible with the additives in the polymer can result in discoloration. In addition, chemical reactions between the biocide and some formulation ingredients can result in deactivation of the biocide. 

Biocides are used at very low levels of active ingredient, typically at about 0.1% or less. In order to be effective the biocide must be evenly distributed over the entire area of the plastic. The use of liquid biocide solutions and solid biocide concentrates help to insure the even dispersion of the active ingredient within the polymer matrix. 

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Formaldehyde and glutaraldehyde are used for disinfection or sterilization of instruments such as fiberoptic endoscopes, respiratory therapy equipment, hemodialyzers, and dental handpieces that cannot withstand exposure to the high temperatures of steam sterilization. They are not corrosive for metal, plastic, or rubber. These agents have a broad spectrum of activity against microorganisms and viruses. They act by alkylation of chemical groups in proteins and nucleic acids. Failures of disinfection or steri... 

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