From Practical Guide to Polyvinyl Chloride

3.9 Microbiocides

PVC-P materials, such as flooring and roofing material, can be prone to microbiological attack in humid or damp conditions. This can be due to micro-organisms, such as algae, bacteria, and fungi, using the plasticiser at the surface of the article as a nutrient carbon food source. This can lead to partial discoloration (pink colour or black specks) which can further cause a tacky surface where dirt can accumulate. Unpleasant odours may also be a consequence.

Biocides function by becoming active on the surface of the material to destroy micro-organisms. Constant microbiocide transfer to the surface is necessary at a rate sufficient to maintain an effective concentration at the surface. This is achieved by the process of diffusion of the plasticiser within the material, the organism also acting as a leaching solvent. Addition levels of the active ingredient are at the 400 2000 ppm level and the active biocide is normally supplied dispersed in a plasticiser or ESBO carrier.

Based on their thermal stability, compatibility, permanence, and broad-spectrum performance against different fungi, the most common microbiocides are 10,10 ?-oxybisphenoxyarsine (OBPA), 2- n-octylisothiazolin-3-one (OIT), and 4,5-dichloro-2- n-octylisothiazolin-3-one (DCOIT).

Various laboratory and accelerated outdoor test methods are available to determine the effectiveness of microbiocides in simulated performance situations covering weathering, water leaching, and resistance to soil burial. These are the areas where performance can be negatively influenced.

Some of the microbiocides mentioned previously also have some limited bacteriocidal activity but specific antibacterial additives may also be necessary to provide...

Products & Services
Wipes and Wipers
Wipes and wipers include wet, dry, and biocide-saturated microfiber cloth, paper, foam, and nonwoven sheets for medical, fiber optic, laboratory, electronic, and other critical cleaning applications.
Chemical Water Treatment Equipment
Chemical water treatment equipment mitigates the formation of scale, calcium carbonate deposits, in process water systems such as cooling towers, boilers and heat exchangers by controlled chemical addition and system monitoring.
Environmental Testing and Analysis Services
Environmental testing and analytical services provide testing of environmental samples such as soil, water, air, and industrial wastes or byproducts.
Surface Finish Comparators

Surface finish comparators are visual and tactile inspection tools that identify the surface qualities of finished workpieces.

Topics of Interest

3.10 Blowing Agents Blowing agents are solid materials that decompose to release gases at particular temperatures matching the appropriate melt viscosity necessary to retain a foam structure. There...

There are many organic and inorganic actives available for use in plasticised PVC and other plastics. The major actives are summarised next and are split into two categories according to whether they...

The microorganisms of importance fall into three broad groups (Figure 2). Viruses may also be mentioned although these are less well documented as an issue for growth in or on plastics. Figure 2: The...

The use of biocides in plastics is commonplace. They are added to protect the plastic itself from degradation by microbes or alternatively to provide an external antimicrobial hygienic surface. The...

3.2 Plasticisers Plasticisers are added to PVC to achieve flexibility and workability. The flexibility or softness is determined by the type of plasticiser and level used in relation to the PVC...