BIAXIALLY ORIENTED POLYPROPYLENE FILM AND ITS MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a film for giving a lapping tape having a shrinkage force at a temperature of lowest viscosity of a resin contained in a prepreg but no large shrinkage force of squeezing out a resin from a molding by retaining a clamping force capable of following to the volumetric change of a partial molding even by abruptly lowering a residual when heated by indicating a tensile strength corresponding to that of a PET film when wound on the molding with good releasability for easily removing from the molding after heating and curing with weak adhesive force with thermosetting resin. SOLUTION: The biaxially oriented polypropylene film comprises a thickness of 15 to 40μm, and stresses of elongating direction when elongated at 30% and 50% at the ambient temperature of 1.7×108 to 2.1×108 Pa and 2.5×108 to 2.9×108 Pa.