The present invention relates to a process for preparing a fluoropolymer in a liquid reaction medium, comprising the following steps: provide a reactor containing a liquid reaction medium comprising water introduce in said reactor ethylene monomers and fluorinated monomers, said fluorinated monomers being selected from tetrafluoroethylene (TFE), chlorotrifluoroethylene (CTFE) or mixtures thereof, pressurize the reactor, initiate polymerization feeding into said reactor a redox initiator comprising an oxidising agent and a reducing agent, wherein said reducing agent in said redox couple initiator is free from sulphur atoms having an oxidation number of 4 or below, wherein the reaction medium is free of fluorinated surfactants.

A film includes a copolymer having a tetrafluoroethylene-based unit and an ethylene-based unit, in which the film has a haze of from 1.2% to 8.0%, an ultraviolet reflectance of less than 17.0%, and a thickness of from 250 to 400 m.