abstract |
(57) [Summary] [PROBLEMS] To have extremely excellent heat resistance and dimensional stability against heat generation and elongation generated during prepreg molding processing, In addition, the present invention provides a prepreg protective film having flatness without roughening the surface of the prepreg. SOLUTION: A polyethylene naphthalate film, A protective film comprising a release layer formed on at least one side thereof, wherein the polyethylene naphthalate film has a melt viscosity of at least 560 Pa ยท s and a center line average surface roughness (Ra) of at most 2 to 50 nm. Protective film for prepreg, characterized in that: |