Pattern design of micro-perforation on composite material for modified atmosphere packaging
Zhang, Lu (2016)
Diplomityö
Zhang, Lu
2016
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi-fe2016121431415
https://urn.fi/URN:NBN:fi-fe2016121431415
Tiivistelmä
The extrusion-coated paperboard tray packaging which contains a tray container and a piece of lidding film is widely used along with MAP technology in fresh food packaging industry. Much research has been done on perforation onto lidding film. This research is based on the attempt of perforating on the tray materials : uncoated paperboard and paperboard coated with PE polymer or PET polymer. The study was an approach to the perforations on the paperboard and how to design its patterns. The study focused on to which degree does the perforation influences the strength of the paperboard materials. The diameter and the shape of perforations were observed. The GTR and WVTR of the materials were tested.
From the comparison of 25 patterns, it is inferred that the better tensile strength could be achieved when the micro-holes placed with more distance and more uniformly. The less perforation done on horizontal direction of the sample, the better tensile properties it gains. The less destructing rows made on the samples, the better tensile strength the sample gets. More even and straight fraction surfaces appeared in MD samples, while CD samples also have slant and more layered fraction surfaces. Tensile strength in MD is close to two times
higher than CD samples. These results are caused by the orientation of the fibers. The appearance differences between micro-holes of the three materials are quite obvious. For manual made perforated hole, the surface is not smooth enough. For laser made perforation, the paperboard got discoloration due to laser, perforation on uncoated board is more flat, outstanding ring circles appeared on PET and PE boards, and a few bubbles could be seen around the ring circle of PET coated board. The perforation could increase the WVTR of three kinds of boards effectively. The design of patterns and the observation of perforations could give the theoretical reference for manufactures or engineers who wants to apply the laser perforation on composite paperboard.
From the comparison of 25 patterns, it is inferred that the better tensile strength could be achieved when the micro-holes placed with more distance and more uniformly. The less perforation done on horizontal direction of the sample, the better tensile properties it gains. The less destructing rows made on the samples, the better tensile strength the sample gets. More even and straight fraction surfaces appeared in MD samples, while CD samples also have slant and more layered fraction surfaces. Tensile strength in MD is close to two times
higher than CD samples. These results are caused by the orientation of the fibers. The appearance differences between micro-holes of the three materials are quite obvious. For manual made perforated hole, the surface is not smooth enough. For laser made perforation, the paperboard got discoloration due to laser, perforation on uncoated board is more flat, outstanding ring circles appeared on PET and PE boards, and a few bubbles could be seen around the ring circle of PET coated board. The perforation could increase the WVTR of three kinds of boards effectively. The design of patterns and the observation of perforations could give the theoretical reference for manufactures or engineers who wants to apply the laser perforation on composite paperboard.