In reply to Woker: I have too much time on my hands. From some test performed by sterling ropes (big in the States):
Summary of Nylon, PET and Spectra Chemical Resistance to DEET
Nylon 1R88, Polyester 1W70, and S-900 Spectra were submitted for chemical resistance testing for DEET (N,N diethyl-m-toluamide). The three samples were immersed separately in “CUTTER” and “OFF” brand insect repellent for a period of twenty-four hours at room temperature. “OFF” contains 95% DEET while “CUTTER” contains only 7% DEET and probably some oil based solvents as well. The results of the testing indicate no loss of strength as measured by tensile strength retention in any of the three samples.
There was one interesting anomaly that occurred only in the case of Nylon and the "CUTTER” brand insect repellent. As mentioned before there was no loss of strength for any of the samples but here there was a 25% increase in the elongation and a decrease in modulus. This basically means that a rope made entirely or mostly out of Nylon may become “rubbery” with a significant amount of exposure to “CUTTER” or other insect repellents with large amounts of oil based solvents.
However, with regard to the chemical in question, DEET, there appears to be no effect on any of the physical properties of the three samples. Hence as “CUTTER” contains only 7% DEET the change in the Nylon elongation and modulus must come from the other solvents in the product. One suggestion to the customer might be to tell the rope users that if they have a rope made of significant amounts of Nylon to use insect repellents with 95-100% DEET instead of ones with some DEET and large amounts of other oil based solvents.
