Static decay time

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

Varying the fatty acid portion of the surfactant can have an effect on antistatic performance. In the example given in Table 5, ethoxylated coconut amine results in the shortest static decay time, whereas ethoxylated stearyl amine results in the longest static decay time (135). 

Table 5. Static Decay Times of Ethoxylated Fatty Amines in High Density Polyethylene...

The compound s static decay time should also be reduced to less than a few seconds. These properties depend on the test specification and requirement called out (such as the military specification MIL-B-81705 or the National Fire Protection Association (NFPA) 99 specification) [1-1, 6-1, 6-2, 6-28]. 

Polymer Antistat Composition (Pius Form, and Supplier Designation) Tested Antistat Loading Level (and Typical Loading Range) Static Decay Time (Seconds) After Various / Ing Periods (Days) Surface Resistivity Exponent (lO ohms/ sq) After Various Aging Periods (Days) ... 

Effectiveness over time Static decay times may start to increase several weeks after processing as antistats become consumed, removed from the surface, or otherwise deactivated. (Overall effectiveness also depends on having enough moisture in the air with which to form a thin surface layer of water.)... 

TABLE 8.1 Static decay-times for electrostatic dissipation (ESD) of batch-mixed and twin-screw extruded composites, measured at 1% cutoff and 50% relative humidity. 

Yang et al. [245] have used TG for the study of the thermal weight loss of low-MW surfactants, used as antistatic agents in HDPE containers. In a typical example of product development Ward et al. [246] have reported the use of TG in combination with static decay and optical measurements for evaluation of the effectiveness of some 13 internal antistatics. With fail/pass criteria of a weight loss of 5% (up to 250°C) and a static decay time of less than 0.5 s at 70% r.h., none of the commercially available surfactants did meet all critical criteria developmental PMMA antistats were reported. 

---