| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject film consisting of a polyester film with at least one side thereof bearing a release layer by designing itself to be such that the whole ray transmittance and the number of projections thereon fall within respective specific ranges to make dielectric strength defect hard to occur even if used in manufacturing thin ceramic sheets and to favorably detect flaws of such ceramic sheets by the aid of transmitted light. SOLUTION: This release film is so designed that the whole ray transmittance is >=88.0% so as to ensure minute flaws of ceramic sheets to be detected when the ceramic sheets are subjected to flaw inspection, and the number of projections <=2 μm in height is <=3/m2 so as to make dielectric strength defect hard to occur even if used in manufacturing ceramic sheets each <=5 μm in thickness. Furthermore, another version of this release film <=25/m2 in the number of projections each >=1.4 μm in height can be used, in particular in manufacturing ceramic sheets each <=3, μm in thickness. By the way, this release film is pref. 12-100 μm in thickness. |
