Study of heat sealing of polymer multilayers[1]E. Planes, L. Flandin

LEPMI UMR CNRS 5279 / LMOPS - Universite de Savoie -Campus Scientifique, Bat. IUT F73376 Le Bourget-du-Lac Cedex, France

Introduction

For building applications ⇒ Use of polymer-metal multilayers[2]

Goal ⇒ Optimization of the seal :Mechanical strength, barrier properties...

Materials

⇒ Investigation of the heat sealing properties of two multilayers

Sealant material : LDPE layer ⇒ Tm = 108 ◦CDifferent heat sealing conditions tested :• Sealing temperature : from 110 to 180◦C

• Dwell time : from 1 to 90s

Methods

Definition of mechanical parameter :

Normalized seal strength SS = Fmax

W×e

⇒ Relation to seal morphology and failure mechanisms

Results

Optimization of heat sealing parameters for LDPE film

•At low sealing temperatures (110-115◦C) : Large instabilities in the mechanical behavior

• For sealing temperatures >120◦C : Mechanical behavior more stable, Increase in stiffness and SS

Same results obtained for the others dwell times tested

⇒ The temperature alters more the properties than the dwell timeIn agreement with the results of Meka and Stehling[3, 4]

Relation mechanical parameters - failure modes

• (A) mode : Low SS

• (B) &(C) modes : SS = SSm

⇒ Solely different in failure mechanism

Case of multilayers

For multilayers : Same relation mechanical parameters - failure modes

With an increasing number of PET layers :• Evidence of new failures modes

• Larger reduction in optimal time-temperature range

Relation microscopic observations - failure modes

• (A) mode : Clear separation between the 2 LDPE layers

• (C) mode : Diffusion of the 2 LDPE layers

• (B1) mode : Formation of a roll at the edges of the seal⇒ This morphological parameter enables to distinguish (B) & (C) modes

Overview

Similar set of optimal heat sealing parameters, reduced for

multilayers

Advantages of multilayers

Mechanical strength SSm increases for multilayers

Acknowlegments

• BARISOL Prebat Project financed by ANR and overviewed by ADEME

• Special thanks to all industrial partners of this project : EDF (B. Yrieix, E. Pons), CSTB (C.

Pompeo, G. Garnier), REXOR (P. Rousset, V. Robin)

References[1] E. Planes, S. Marouani, and L. Flandin. Optimizing the heat sealing parameters of multilayers polymeric films.

Journal of Materials Science, 46:5948–5958, 2011. 10.1007/s10853-011-5550-4.

[2] Kuninari Araki, Daigorou Kamoto, and Shin ichi Matsuoka. Optimization about multilayer laminated film andgetter device materials of vacuum insulation panel for using at high temperature. J. Mater. Process. Technol.,209(1):271 – 282, 2009.

[3] P. Meka and F. C. Stehling. Heat sealing of semicrystalline polymer films. 1. calculation and measurement ofinterfacial temperatures: Effect of process variables on seal properties. Journal of Applied Polymer Science,51(1):89–103, 1994.

[4] FC Stehling and P Meka. Heat sealing of semicrystalline polymer-films .2. effect of melting distribution onheat-sealing behavior of polyolefins. Journal of Applied Polymer Science, 51(1):105–119, Jan 3 1994.