Cantor
Blown Film Extrusion

Kirk Cantor

Blown Film Extrusion

2nd Edition

Hanser Publishers, Munich

Hanser Publications, Cincinnati

The Author:
Prof. Kirk Cantor, Pennsylvania College of Technology, Williamsport, PA, USA

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Library of Congress Cataloging-in-Publication Data
Cantor, Kirk.
Blown film extrusion / Kirk Cantor. 2nd ed.
p. cm.
1. Plastic films. I. Title.
TP1183.F5C36 2011
668.4’95dc22
2011008677

Bibliografische Information Der Deutschen Bibliothek
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ISBN 978-3-446-41705-2
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© Carl Hanser Verlag, Munich 2011
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Coverdesign: Stephan Rönigk
Typeset: Manuela Treindl, Fürth
Printed and bound by Kösel, Krugzell
Printed in Germany

Acknowledgements

I am grateful for the many people that have supported my efforts to write this book
and develop the software included. Funding for these projects was provided through
a grant to the Plastics Resources for Educators Program (PREP) by supporters at the
National Science Foundation. My colleagues at Pennsylvania College of Technology
provided administrative support.
I am very thankful for my good friend and co-worker, Tim Weston, for his vision and
leadership through PREP. Other PREP colleagues for whom I am thankful are Alex
Bierly, who masterfully d all of the graphics for the simulator, and our other very
talented artists, Mike Fleck, Matt Byers, and Craig Reitz.
Many thanks go to another close friend and mentor, Chris Rauwendaal, for not only
helping with the text of this book, but for teaching me so much about extrusion over
the years. I am thankful for the text review and insight given to me by Robert Krycki.
My friends at Hanser have been very helpful with the creation of the manu and
artwork. Thanks especially to Christine Strohm for her years of encouragement and
assistance.
Finally, I am most thankful for the support of my devoted family and the opportunity
given to me by God. My lovely wife, Patsy, and my four beautiful daughters, Kristen,
Caylee, Kelsey, and Shannon, have patiently endured my hours away and have even
cheered me on to completion.
January 2011

Kirk Cantor

Contents

Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1

Materials for Blown Film . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1
Polymers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1.1 Polyethylene (PE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.1.2 Low Density Polyethylene (LDPE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.1.3 High Density Polyethylene (HDPE) . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.1.4 Linear Low Density Polyethylene (LLDPE) . . . . . . . . . . . . . . . . . . . . 9
1.1.5 Metallocene Polyethylene (mPE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
1.1.6 Polypropylene (PP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
1.1.7 Polystyrene (PS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.1.8 Ethylene Vinyl Acetate (EVA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.1.9 Ethylene Vinyl Alcohol (EVOH) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
1.1.10 Polyvinyl Chloride (PVC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
1.1.11 Polyvinylidene Chloride (PVDC) . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
1.1.12 Polyamide (PA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
1.1.13 Polyurethane (PU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
1.2
Additives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
1.2.1 Antiblocking Agents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
1.2.2 Antioxidants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
1.2.3 Antistatic Agents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
1.2.4 Colorants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
1.2.5 Lubricants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
1.2.6 Reinforcements and Fillers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
1.2.7 Stabilizers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
1.2.8 Tackifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

2

Extrusion Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2.1
Extruder Hardware Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2.1.1 Drive System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
2.1.1.1 Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

VIII

Contents

2.2

3

2.1.1.2 Speed Reducer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
2.1.1.3 Thrust Bearing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
2.1.2 Feed System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
2.1.3 Screw/Barrel System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
2.1.3.1 Screw . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
2.1.3.2 Barrel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
2.1.4 Head/Die System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
2.1.4.1 Head Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
2.1.4.2 Adapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
2.1.4.3 Breaker Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
2.1.4.4 Melt Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
2.1.4.5 Die . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
2.1.5 Instrumentation and Control System . . . . . . . . . . . . . . . . . . . . . . . . 38
2.1.5.1 Temperature Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
2.1.5.2 Head Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
2.1.5.3 Motor Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Extrusion Functional Zones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
2.2.1 Solids Conveying . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
2.2.1.1 Gravity-Induced Region . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
2.2.1.2 Drag-Induced Region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
2.2.2 Melting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
2.2.3 Melt Pumping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
2.2.4 Mixing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
2.2.4.1 Distributive Mixing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
2.2.4.2 Dispersive Mixing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
2.2.4.3 Mixing Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
2.2.5 Degassing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
2.2.6 Die Forming. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Hardware for Blown Film . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
3.1
Upstream Components . . . . . . . . . . . . . . . .