| 摘要 |
<p>PURPOSE:To bond very easily a tear piece on a bag body, by bonding with heat the tear piece on the bag body, weakening simultaneously the tear piece and the bag body with heat. CONSTITUTION:A nearly triangle bag body 1 is formed by a melting cut of two sheets of non-extensible polypropylene film. Next, two sheets of film are laminated, which comprise a front film 5a made of an extensible polypylene film and a rear film 5b made of a non-extensible polypropylene film, to form a belt of tear piece 5 with double layers which is arranged to confront the bag body 1 with the side of the rear film 5b. Next an electric iron 7 is contacted on the tear piece 5 in the longitudinal direction to weld with heat at the required position of the bag body 1. In this case, the heating temperature of the electric iron 7 is higher than the softening temperature of the rear film 5b and lower than that of the front film 5a. Accordingly the front film 5a is not weakened but the tear piece 5 is weakened to be welded together with the bag body 1.</p> |
