STATIC DISSIPATION

Statexan ITA Static control agents Static decay Static decay times Static dissipation Static drying Static electricity Static eliminating devices Static mixers Static phenomena... 

With sheet or pipe, multilayer coextmsion can be used. SoHd outer-soHd core coextmsion can place an ABS grade on the outside that has special attributes such as color, dullness, chemical resistance, static dissipation, or fire-retardancy over a core ABS that is less expensive or even regtind. 

Reiaforced plastics may also iaclude fillers (qv), which are iaexpeasive materials such as calcium carboaate used to displace resia and reduce cost curing agents (catalysts), promoters, inhibitors, and accelerators, which affect thermosetting resia cure colorants release agents (qv) to faciUtate removal from the mold and other additives which can impart a wide variety of properties to the finished part, such as fire resistance, electrical conductivity, static dissipation, and ultraviolet resistance. 

The static decay test is a good measure of the static dissipative nature of an object. However, the test is controlled by the object s resistance to ground. Objects that have a high resistance, such as insulators, will not readily accept an induced charge or decay an induced charge. The static decay test is most suited for objects with resistances of 10 or less (52). 

Materials that have the abiUty to dissipate a charged formed, by any means including tribocharging and induction, on the material are referred to as static dissipative. There is a correlation between static dissipation and surface resistance. EIA-541 currently defines the static dissipative range as 10 to 10 ... 

The term antistatic agent is generally used to describe a substance that is added to a material to make that material static dissipative. The two biggest markets for antistatic agents are textiles and plastics. 

Common conductive polymers are poly acetylene, polyphenylene, poly-(phenylene sulfide), polypyrrole, and polyvinylcarba2ole (123) (see Electrically conductive polymers). A static-dissipative polymer based on a polyether copolymer has been aimounced (124). In general, electroconductive polymers have proven to be expensive and difficult to process. In most cases they are blended with another polymer to improve the processibiUty. Conductive polymers have met with limited commercial success. 

Internal surfactant antistats ate physically mixed with the plastic resin prior to processing. When the resin is melted, the antistat distributes evenly in the polymer matrix. The antistat usually has some degree of solubiUty in the molten polymer. However, when the polymer is processed (extmded, molded, etc) into its final form and allowed to cool, the antistat migrates to the surface of the finished article due to its limited solubiUty in the solidified resin. The molecule of a surface-active agent is composed of a polar hydrophilic portion and a nonpolar hydrophobic portion. The hydrophilic portion of the surfactant at the surface attracts moisture from the atmosphere it is the moisture that has the static dissipative effect. 

Surface Resistance Measurement of Static Dissipative Planar MaterialsD SW.W, EOS/ESD Association, 1991. 

Use alternate solvent with reduced static potential Use conductive materials of construction Add antistatic agent to nonpolar solvent Check conductivity prior to feeding Use static dissipating linings if applicable... 

Since static discharges frequently occur at the liquid interface as liquid drains from the wetted wall, a vapor ignition hazard may also exist [ 157,159]. These discharges may be either brush types or PBDs (2-6.2 and 2-6.5). In 1997 it was concluded that Manufacturers have so far not paid attention to requests by the operators of enamel apparatus for a coating which is completely or partially capable of dissipation [159]. However, this situation is believed to be changing and it might now be possible to specify special static dissipative coatings for the vessel and stirrer. 

The Geon Company PVC Rigid, Flexible, High Heat, Composites, Packaging, Static Dissipative, Weatherable... 

Static-dissipative (antistatic) material One with an electrical resistivity that is low enough to make it incapable of accumulating hazardous concentrations of static charges when grounded. 

Static dissipative grades covers, guards, access panels, machine windows and doors, static control shields, glove boxes, electronic equipment, process instrumentation, conveyor line covers, clean room windows and doors, partitions and pass through modules... 

The texturing sheet may also contain a plastic coating that transfers to the laminate surface during the laminating process to provide special surface properties. The caul plate itself may be smooth or textured and act directly as the release. Immediately beneath this release sheet, there may be a decorative layer or a ply that imparts special properties such as a metallic foil for electrical conductivity or a static dissipating layer. If the decorative layer is a printed... 

Schwenzfeuer, K., and Glor, M., The Safety Concerns between Conductive Type C and Static Dissipating FIBCs, Institute of Safety and Security, Switzerland, 16th January 1998. 

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