| abstract |
Provided are an ETFE film which is unlikely to wrinkle when stretching and contracting, and a method for producing the same. The ethylene-tetrafluoroethylene copolymer film is characterized in that the degree of crystallization thereof obtained from formula (1) is 55-70%, and the quasicrystal layer proportion thereof obtained from formula (2) is 10-20%, based on a peak area S 20 near 2θ=20°, a peak area S 19 near 2θ=19° and a peak area S 17 near 2θ=17° along a diffraction intensity curve obtained by measuring using the X-ray diffraction method. Degree of crystallization (%)=(S 19 +S 20 )/(S 17 +S 19 +S 20 )×100 (1) Proportion of quasicrystal layer (%)=S 20 /(S 17 +S 19 +S 20 )×100 (2) |