ESD Systems - Questions And Answers

I have two questions about one material. Anti-stat bags. 1. How effective are anti-stat bags with a relative humidity of less than 20 % and temperatures as high as 110 degrees F. 2. How do you put a spec on an anti-stat (ohms/sq. etc.) bag to ensure maximum protection and re-use. - Jim Fitzgibbons, General Instruments, Horsham, PA

The static dissipative polyethylene (PE) (clear) we use in our bags is far superior than the "topically treated washed" products. Our bags are made with volume loaded polyethylene which cannot be washed off and is inherent in the film. The PE resin that we use and all the additives are developed to minimize contamination. Our anti-stat clear bags are pre-conditioned and tested at both 50% and 12.5% RH levels to have a surface resistivity of less than 1x10^11 ohms. (old nomenclature = ohms/square) Testing: You can perform two tests to ensure the proper operation of the bags - perform a resistance test on the bag film to <1x10^11 ohms @100 volts [using two five pound probes and megohmeter, ESD S11.31-1994 and ESD DS20.20-1998], tribocharge test, static decay of less than or equal to 140 milliseconds, per FTMS 101C, Method 4046

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