The back-and-forth wiping of acrylic surfaces attracts and retains small particles by intensifying positive and negative surface charges. Laminar flow over acrylic surfaces also facilitates electrostatic induction which enables further particle retention. The result is a surface that is impossible to clean because particulate matter and contaminants cling to charged surfaces.
The removal of contaminants from charged surfaces is unlikely without the use of ionizing equipment or frequent and labor intensive cleaning with special anti-static solutions. Shifting surface charges cause the unpredictable release of accumulated particles which then threaten sensitive materials with contamination. The reason static dissipative PVC is favorable in ultra-clean environments is that maintaining the cleanliness of acrylic enclosure drives up maintenance costs and shrink the bottom line.
An aseptic environment requires frequent sterilization with disinfectants such as alcohol. Unfortunately, most conventional biocides, including industry-standard IPA solutions, degrade acrylic causing cracks and discoloration. Static dissipative PVC resists alcohol and most other sterilizing solutions. Therefore it eliminates corrosion caused by standard disinfecting procedures and extends the life of an enclosure.
The most detrimental side effects of acrylic based cabinets and enclosures appear when unpredictable electrostatic discharge (ESD) damages or destroys static-sensitive materials. Hand wiping and strong laminar flow contribute to surface static which can deliver up to 20,000 volts to semiconductors, electronics, and other sensitive materials. The potential for ESD rises in low-humidity environments such as with nitrogen-purged benchtop and standing desiccator cabinets
Why Are Acrylic Components So Common?
Low initial cost, light weight, transparency, and strength offered by acrylic components explain its normalization in cleanrooms and other critical environments. Most manufacturers offer acrylic cabinets because limited budgets restrict access to higher quality components. Acrylic is not sufficient in the most critical aseptic environments because its less desirable physical properties inflate the cost of ownership in the long term, despite its economical price point.
Why Is Static Dissipative PVC a Better Option than Acrylic?
Chemically embedded dissipative layers exemplify the most compelling reason for the use of static dissipative PVC in cleanroom and laboratory environments. The structure and materials of these layers resist corrosive chemicals, limit particle generation when cleaning, and minimize static attraction. In the most demanding cleanroom and aseptic environments, static dissipative PVC components maintain a resistivity of 107 ohms/sq. in. within commercial operations. Transparent housings and chemical resistant technology provide the ultimate solution for high-visibility monitoring without fogging and support long-lasting performance.
See Production Automation’s full line of Static Dissipative PVC enclosures.
Revised copy with permission from