Molecular Orientation Effect of Heat-Sealed PP Film on Peel Strength and Structure


Heat sealing properties are optimized by controlling temperature, pressure and dwell time, while film strength depends on the drawn ratio and the molecular orientation of the film. However, heat seal strength of polymer films with high drawn ratio shows lower peel strength, because the adhesion of films needs a higher heat sealing energy for molecular orientation relaxation at heat sealing. In the present study, polypropylene films with a drawn ratio of 1.0×, 1.5×, and 2.5× are heat sealed by using the heat sealing technique. The heat sealing condition is set to heat sealing time 1.0 s, sealing pressure 0.2 MPa, and heat sealing temperature 145°C. The effect of drawn ratio and stabilization temperature of PP films for peel strength are investigated using T-Peel test, DSC, FT-IR, and Raman spectroscopy. As a result, it is found that the peel strength is decreased with increasing the drawn ratio and stabilization temperature of PP films. The difference of ?H and melting point from the result of DSC measurement are exhibited for 1.5× drawn ratio film as compared with 2.5× one. In addition, FT-IR imaging and Raman line mapping reveal the influence and variation of high order structure for heat sealed parts of the drawn PP films.

Share and Cite:

Yamada, K. , Miyata, K. , Konishi, R. , Okada, K. and Tsujii, T. (2015) Molecular Orientation Effect of Heat-Sealed PP Film on Peel Strength and Structure. Advances in Materials Physics and Chemistry, 5, 439-446. doi: 10.4236/ampc.2015.511044.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] Hashimoto, Y., Ishiaku, U.S., Leong, Y.W., Hamada, H. and Tsujii, T. (2006) Effect of Heat-Sealing Temperature on the Failure Criteria of Oriented Polypropylene/Cast Polypropylene Heat Seal. Polymer Engineering & Science, 46, 205-214.
[2] Aithani, D., Lockhart, H., Auras, R. and Tanprasert, K. (2006) Heat Sealing Measurement by an Innovative Technique. Packaging Technology and Science, 19, 245-257.
[3] Tetsuya, T., Hashimoto, Y., Ishiaku, U.S., Mizoguchi, M., Leong, Y.W. and Hamada, H. (2006) Effect of Heat-Sealing Temperature on the Properties of OPP/CPP Heat Seals. Part II. Crystal-linity and Thermomechanical Properties. Journal of Applied Polymer Science, 99, 513-519.
[4] Farris, S., Cozzolino, C.A., Introzzi, L. and Piergiovanni, L. (2009) Effects of Different Sealing Conditions on the Seal Strength of Polypropylene Films Coated with a Bio-Based Thin Layer. Packaging Technology and Science, 22, 359-369.
[5] Tetsuya, T., Ishiaku, U.S., Mizoguchi, M. and Hamada, H. (2005) The Effect of Heat Sealing Temperature on the Properties of OPP/CPP Heat Seal. I. Mechanical Properties. Journal of Applied Polymer Science, 97, 753-760.
[6] Yuan, C.S., Hassan, A., Ghazali, M.I.H. and Ismail, A.F. (2007) Heat Sealability of Laminated Films with LLDPE and LDPE as the Sealant Materials in Bar Sealing Application. Journal of Applied Polymer Science, 104, 3736-3745.
[7] Mihindukulasuriya, S.D. and Lim, L.-T. (2013) Heat Sealing of LLDPE Films: Heat Transfer Modeling with Liquid Presence at Film-Film Interface. Journal of Food Engineering, 116, 532-540.
[8] Planes, E., Marouani, S. and Flandin, L. (2011) Optimizing the Heat Sealing Parameters of Multilayers Polymeric Films. Journal of Materials Science, 46, 5948-5958.
[9] Yamada, K., Miyata, K., Konishi, R., Tsujii, T. and Hashimoto, Y. (2015) Heat Seal Processing by Using Various Seal Bar Shape. AIP Conference Proceedings, 1664, 080002-1-080002-5.
[10] Sadeghi, F., Ajji, A. and Carreau, P.J. (2007) Analysis of Row Nucleated Lamellar Morphology of Polypropylene Obtained from the Cast Film Process: Effect of Melt Rheology and Process Conditions. Polymer Engineering & Science, 47, 1170-1178.
[11] Cole, K.C., Perrin-Sarazin, F. and Dorval-Douville, G. (2005) Infrared Spectroscopic Characterization of Polymer and Clay Platelet Orientation in Blown Films Based on Polypropylene-Clay Nanocomposite. Macromolecular Symposia, 230, 1-10.

Copyright © 2023 by authors and Scientific Research Publishing Inc.

Creative Commons License

This work and the related PDF file are licensed under a Creative Commons Attribution 4.0 International License.