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Evaluation of Jaw Profile on Heat Sealing Performance of Metallised Flexible Packages
Author(s) -
de Oliveira Léa Mariza,
de Assis Fonseca Faria José
Publication year - 1996
Publication title -
packaging technology and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.365
H-Index - 50
eISSN - 1099-1522
pISSN - 0894-3214
DOI - 10.1002/(sici)1099-1522(199612)9:6<299::aid-pts373>3.0.co;2-q
Subject(s) - engineering drawing , mechanical engineering , materials science , high heat , engineering , composite material
Different profiles of jaws are used in the Brazilian market for heat sealing flexible materials used in food packaging by heated bar. The objective of this study was to evaluate the influence of the jaw profile on the quality of the top and bottom heat seals of pouches made of biaxially metallized polypropylene/biaxially co‐extruded polypropylene (BOPPmet/BOPPcoex) amd biaxially metallized polypropylene/low density polyethylene (BOPPmet/LDPE). These materials are traditionally used for snacks and ground coffee packages. Five jaw profiles were evaluated: one flat and four grooved, using lengthwise, crosswise at profiles 120 and 90° and inclined. The heat sealing temperature and time were optimized for the two packaging materials for all profiles. The sealing pressure was fixed at 40 lbf/in 2 . Heat sealing quality was evaluated through visual examination, integrity, tensile strength and drop testing. All the tests were done before and after transport simulation on the packages. BOPPmet/BOPPcoex 100 g snack packages and BOPPmet/LDPE 250 g ground coffee packages were prepared under laboratory conditions. The transport simulation was done on these packages by placing them into paperboard boxes (for snacks) or kraft paper sacks (for ground coffee). The BOPPmet/BOPPcoex packages presented integrity problems for all the profiles tested. The best heat sealing, tensile strength, drop impact resistance and appearance were obtained with the crosswise 90 and 120° and inclined grooved profiles, therefore these profiles are the recommended ones for top and bottom heat sealing of snacks MOPP/met/BOPPcoex packages. The flat profile had the worst performance among the ones that were studied. Heat sealing quality was not affected by the transport simulation, for all profiles. The BOPPmet/LDPE packages did not show integrity problems. However, the transport simulation reduced the heat sealing quality for all profiles. The crosswise 120 and 90° grooved profiles showed similar performance and they are the recommended ones for BOPPmet/LDPE packaging of ground coffee or any product of similar appearance and density. The inclined, lengthwise and flat profiles are not recommended for these applications.