Fabrication of breathable film using diffractive multi-beam nanosecond laser patterning of polypropylene film

Abstract

This paper demonstrates the manufacturing of breathable film by patterning micro-holes on the surface of oriented polypropylene films by means of diffractive multi-beam nanosecond laser assisted micro-machining technology. Using a 1×3 diffractive beam splitter, we have split a single laser beam into three parallel beams and have irradiated them sequentially in a row at a constant speed to overlap three pulses in each irradiated spot of the film surface. As a consequence, micro-holes' array of high depth and wide diameter is formed on the film surface. We also fabricated breathable polypropylene films by single laser beam engraved micro-holes' array. Multi-pulse engraved micro-holes show better aspect ratio, compared to single pulse engraved micro-holes. To study the influence of average pulse energy on breathability of the films, we have fabricated micro-holes array on the polypropylene film surface by varying the average pulse energy. Furthermore, we investigate the oxygen transfer rate through the multi-pulse irradiated breathable films. The experimental results exemplify that, oxygen transfer rate increases with the number of irradiated laser pulses in each spot of the oriented polypropylene films. The fabricated breathable films will pave the way for technological advancement, especially in packaging, and manufacturing sanitary pad, diaper and water proof vinyl. © 2020, Japan Laser Processing Society.