Patent ID: 6918559

Claim:
A slitting method for manufacturing a battery separator-use resin film object comprising the steps of: providing a slitting device comprising a feeding roll for feeding a film object from a scrolled film object with its rotational velocity being controlled; a slitting blade for slitting said film object so as to have a predetermined width; a sensor for detecting a tension of said film object and a wind-up roll for winding up said film object while controlling the tension of said film object, and slitting said film object by using said slitting device in a manner so as to satisfy the following conditions 1 and 2: 5×9.8×10 4 ≦T/L ≦5×9.8×10 5 (Condition 1) 1 ≦R/T ≦5 (Condition 2) where L is a thickness (m) of said film object, R is a rotational velocity (m/min) of said feeding roll and T is a tension (N/m) of said film object after having been subjected to the slitting operation.