| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a heat sealing method capable of easily, consistently and reliably forming a weakened seal part between multi-layered films having a heat seal layer consisting of a mixture of two kinds of polyethylene with the difference in densities of both polymers being <0.02 g/cm<SP>3</SP>, and a flexible packaging container having the weakened seal part formed by the method. <P>SOLUTION: In the heat sealing method, when forming the weakened seal part between the multi-layered film by holding the superposed multi-layered films by two heat sealing bars arranged opposite to each other and performing the heat sealing thereof for 1-6 seconds, the spacing between the two heating sealing bars is adjusted so as to be 75-95% of the total thickness of the superposed multi-layered films. Then, the temperature of one of the heat sealing bars is set to be in a temperature range of 60-150°C, and the temperature of the other is set to be in a temperature range of 110-220°C according to the thickness of each multi-layered film and the mixing ratio of the two kinds of polyethylene, and a temperature difference of ≥5°C is maintained between both temperatures. <P>COPYRIGHT: (C)2009,JPO&INPIT |
