Bis(trifluoromethanesulfonyl)imide‐ T ype Ionic Liquids as Excellent Antistatic Agents for Polyurethanes

Surface resistivity ( ρ s ) of polyurethane (PU) films is reduced from 2.1 × 10 12 to 9.4 × 10 10 ohm sq −1 by addition of 1‐butyl‐3‐methylimidazolium bis(trifluoromethanesulfonyl)imide ([C 4 mim][Tf 2 N]) for only 10 ppm. Addition of [Tf 2 N]‐type ionic liquids (ILs) for 1 000 ppm leads to the reduction of not only ρ s from 10 12 to 10 9 ohm sq −1 but also volume resistivity ( ρ v ) from 10 9 to 10 7 ohm cm, suggesting that the ILs are uniformly incorporated into the PU films. These PU films have ρ s in the order of 10 9 ohm sq −1 even after methanol washing. The antistatic effects are attributed to ionic conductivity of the PU films, which is achieved by low glass transition temperatures of both PU films and [Tf 2 N]‐type ILs. These results suggest that [Tf 2 N]‐type ILs are excellent antistatic agents for PUs.