PURPOSE: To provide a method for piercing of a notch of a polymer film wherein a thermoplastic polymer film-made excellent quality network structure can be certainly easily manufactured without requiring a high grade notch forming technique, i.e., making a thickness of an unpierced part thin.
CONSTITUTION: In a method for piercing of a notch of a polymer film wherein a thermoplastic high molecular film 1 in which a plurality of notches 2 having an unpierced part 1a at the bottom part are formed by elongating lengthwise is heated, elongated in the same direction as the elongated direction of each notch 2, and the notch 2 is pierced, only a partial linear or band-like heated area H in a lengthwise direction of the film 1 is heated, and elongation is given in an elongated direction of the notch 2 to concentrate deformation to the heated area H. Thereby, the unpierced notch 2 is pierced. Besides, the heated area H is gradually transferred according to an elongated state, and finally elongation of the whole of the film 1 and piercing of each notch 2 are carried out.
TANAKA YASUHIKO
KOBAYASHI NAOYUKI
