| 摘要 |
PROBLEM TO BE SOLVED: To propose a method for producing a square bag of a thermoplastic synthetic resin in which seams are linked together airtightly and toughly. SOLUTION: In a method for producing a square bag of a thermoplastic synthetic resin comprising side wall cloths and a bottom wall cloth, the seams of the side wall cloths and the bottom wall cloth and the seams of the side wall clothes are sewn 3 by a sewing machine and ultrasonic welding-processed 4 in the seam direction across perforations. |
