Testing electrostatic properties of polyurethane coated textiles used for protective clothing

The objective of the study was to test the electrostatic properties of textiles used for protective clothing worn in flammable and potentially explosive environment. The protective clothing is intended for multi-use and, apart from wear and stretching during use, it is also exposed to impacts of various cleaning agents. The testing was carried out in according with EN 1149-1; 1995 specifying requirements for elecrtostatic properties and testing methods for protective clothing to be worn in specific situations. The objective was to test whether there is a likelihood of fire due to the electric discharge. EN 1149-1 requires measuring surface resistance at 25% +/- 2% relative humidity and temperature of 23degreesC +/- 1degreesC. Measurements were taken on knitting of varying materials coated with polyurethane. The knittings used were made of polyamide, polyester and cotton. All materials were coated with the same polyurethane coating. All samples were tested for surface resistance before and after five dry-cleanings and machine washings. In addition to the require European standard, surface resistance was also measured at the following relative humidity. 35%, 45%, 55% and 65%. The results were processed by the correlation analysis and shown graphically.