Laser processing has been widely used for many years and in almost all industries. There are many types of polymer material which are industrially processed by lasers. In packaging of fresh products such as fruits and vegetables, films with high oxygen transmission rate (OTR > 10,000 cc/m~2/day) are required for extending their shelf life. Laser perforation is one of the techniques for increasing the gas transmission rate through the formation of tiny holes in the film. The shape and size of perforated micro holes must be affected not only by the laser pulse energy and duration but also by the high-order structure of films. However, studies on the relationship between film structure and perforation behavior have rarely been reported. Therefore, the objective of this study was set to investigate the influence of sequential biaxial stretching conditions of polypropylene films on the perforation behavior to make micro holes.
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