Patent ID: 6375603
Filing Date: 2002-04-23
Classification: B26F,B65B,B65D

Abstract:
A method of producing a bag for packing powder, comprising the steps of:using a composite sheet, said composite sheet being obtained by laminating film (B) having holes with any of paper, cloth cotton or minutely perforated film (A), said film (B) having holes obtained by disposing a resin film on a metallic cylinder or porous plate furnished with a plurality of openings, and applying a negative pressure suction to the resin film from a back of the metallic cylinder or porous plate, while heating the resin film at its softening point or higher, so that the resin film at the openings is drawn toward the back of the metallic cylinder or porous plate to thereby provide protrudent hole-forming portions wherein said resin film comprises a plurality of resin layers different from each other, the resin of an outermost layer having a melting point which is at least 5Â° C. lower than those of other resin layers, and forming said composite sheet into a bag in such a manner that the protrudent hole-forming portions of the film (B) having holes are directed inwards.