Effects of aging, wiping and humidity on surface resistivity of polyethylene and polypropylene boxes

Measurements were made to determine the effects of aging, wiping and humidity on the surface resistivity of blue surfactant-added polyethylene and polypropylene tote boxes. Over 100 samples with lot date codes between 1984 and 1997, made by several different manufacturers, were tested from the current stock of totes used in manufacturing and storage areas. Without exception, the totes had surface resistivity less than 10/sup 12/ /spl Omega//square when measured in situ at 45-55% humidity per ANSI/EOS/ESD-S11.11-1993. There was no correlation between surface resistivity and age of the totes. It was concluded that the service life of the totes in current stock is greater than 10 years.