Co-Rotating Twin-Screw Extruders - Fundamentals, Technology, and Applications

365 Pages·2008·9.717 MB·365\365

by  Kohlgrüber, Klemens (Eds.)

Klemens Kohlgrüber
Co-Rotating
Twin-Screw
Extruders
Fundamentals, Technology, and Applications
With contributions by
Bayer Technology Services GmbH, Coperion Werner & Pfleiderer
Leverkusen, Germany GmbH & Co. KG, Stuttgart, Germany
Dr.-Ing. Michael Bierdel Dipl.-Ing. Herbert Christ,
Dr.-Ing. Jens Hepperle Dipl.-Ing. Ralf Davids
Dr.-Ing. Jörg Kirchhoff Dr.-Ing. Peter Heidemeyer,
Dr.-Ing. Thomas König Dipl-Ing. Frank Lechner
Dr.-Ing. Klemens Kohlgrüber Dipl.-Ing. Hans-Joachim Sämann
Dipl.-Ing. Ulrich Liesenfelder Dipl.-Ing. Ulrich Weller
Dr.-Ing. Reiner Rudolf Dr.-Ing. Werner Wiedmann
Dipl.-Ing. Martin Ullrich Dipl.-Ing. Reinhard Wuttke
Carl Hanser Publishers, Munich • Hanser Gardner Publications, Cincinnati
The Editor:
Dr.-Ing. Klemens Kohlgrüber, Bayer Technology Services GmbH, D-51368 Leverkusen, Germany
Translation:
SDL Multilingual Services GmbH & Co KG, D-70563 Stuttgart, Germany
Distributed in the USA and in Canada by
Hanser Gardner Publications, Inc.
6915 Valley Avenue, Cincinnati, Ohio 45244-3029, USA
Fax: [phone]
Phone: [phone] or 1-800-950-8977
www.hansergardner.com
Distributed in all other countries by
Carl Hanser Verlag
Postfach 86 04 20, 81631 München, Germany
Fax: [phone]
www.hanser.de
The use of general descriptive names, trademarks, etc., in this publication, even if the former are not especially
identified, is not to be taken as a sign that such names, as understood by the Trade Marks and Merchandise Marks
Act, may accordingly be used freely by anyone.
While the advice and information in this book are believed to be true and accurate at the date of going to press,
neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions
that may be made. The publisher makes no warranty, express or implied, with respect to the material contained
herein.
Library of Congress Cataloging-in-Publication Data
Kohlgrüber, Klemens.
[Gleichlaufige Doppelschneckenextruder. English]
Co-rotating twin-screw extruder / Klemens Kohlgrüber.
p. cm.
Includes index.
ISBN-13: 978-1-56990-422-0 (hardcover)
ISBN-10: 1-56990-422-7
1. Plastics--Extrusion--History. 2. Plastics machinery--History. I.
Title.
TP1175.E9K64 2007
668.4‘13--dc22
2007037181
Bibliografische Information Der Deutschen Bibliothek
Die Deutsche Bibliothek verzeichnet diese Publikation in der Deutschen Nationalbibliografie;
detaillierte bibliografische Daten sind im Internet über <http://dnb.d-nb.de> abrufbar.
ISBN 978-3-446-41372-6
All rights reserved. No part of this book may be reproduced or transmitted in any form or by any means, electronic or
mechanical, including photocopying or by any information storage and retrieval system, without permission in wirting
from the publisher.
© Carl Hanser Verlag, Munich 2008
Production Management: Oswald Immel
Typeset by Mitterweger & Partner, Plankstadt, Germany
Coverconcept: Marc Müller-Bremer, Rebranding, München, Germany
Coverdesign: MCP • Susanne Kraus GbR, Holzkirchen, Germany
Printed and bound by Kösel GmbH & Co. KG, Altusried-Krugzell, Germany
Preface
The co-rotating twin-screw is used in many of today’s industries, particularly in polymer
processing. However, the development of this type of machine goes back a long way. Key
contributionstothedevelopmentoftheco-rotatingtwin-screwweremadebyemployeesof
thechemicalindustry:abasicpatentforMeskatandErdmenger’s“threadedscrews”of1944
wasgrantedin1953andinthesameyear,Bayerawardedanexclusiveworldwidelicensefor
thepatentutilityrightstoWerner&Pfleiderer.
The first twin-screw compounder (ZSK) went into production at Werner & Pfleiderer in
1957, marking the beginning of a success story for this type of machine. The first major
applicationswereinthechemicalindustry.Today,themachineispredominantlyusedinthe
plastics industry,e.g.,in extrusion and compounding.These screw machines are therefore
alsoknownasextrudersandthetwin-screwisknownasthetwin-screwextruder.
The2007internationalplasticstradefairandthe50thanniversaryoftheZSKhaveinspired
Bayer(BayerTechnologyServices)andWerner&Pfleiderer(CoperionWerner&Pfleiderer)
topublishabookcoveringthehistory,principlesandapplications,andcurrentstate-of-the-
art of this technology. The book is based on a seminar regularly held by the editor and
organized by the Association of German Engineers (VDI) entitled“The co-rotating twin-
screwextruder”.
As the book contains contributions from several authors,readers are also offered a variety
ofviewpoints.Iwouldliketotakethisopportunitytoofferheartfeltthankstoallauthorsfor
their contributions. I would particularly like to thank Mrs. M. Stüve of Carl Hanser
PublishersandmycolleagueMr.J.Hepperlefortheirinvaluableassistanceinthelayoutand
editing.I would also like tothank Mr.W.Wiedmann of CoperionWerner& Pfleiderer for
theorganisationof theCWPcontributionsandforbeingamajordrivingforcebehindthe
project.
August2007 KlemensKohlgrüber
Contents
1 Introduction ........................................................... 1
2 HistoricalDevelopmentof theCo-RotatingTwinScrew...................... 9
2.1 Introduction ....................................................... 9
2.2 EarlyDevelopments................................................. 9
2.2.1 BasicGeometry............................................... 10
2.2.2 BasicPatents................................................. 13
2.2.2.1 BasicPatentof theThreadedScrew ...................... 13
2.2.2.2 BasicPatentforKneadingDiscs,DBP[16],USP[17],
DBP[20] ............................................ 15
2.2.2.3 BasicPatentforModularDesign......................... 18
2.3 PioneeringPeriod................................................... 20
2.3.1 MachineDevelopment......................................... 20
2.3.2 UseinChemicalProcesses...................................... 20
2.3.3 Licensing.................................................... 22
2.3.4 RecognitionforR.Erdmenger .................................. 22
2.4 NewHighViscosityTechnologywithCo-RotatingExtruders............... 23
2.4.1 ScrewMachinesinProcessEngineering........................... 23
2.4.2 SimilarityTheoryforScrewMachinery........................... 23
2.4.3 VersatileHighViscosityProcesses................................ 25
2.5 SpecialDevelopmentsfromBayer-Hochviskostechnik
(HighViscosityTechnologyGroup).................................... 27
2.5.1 ExtendedKinematics,ProfileGeometries ......................... 27
2.5.2 ClearanceStrategies........................................... 28
2.6 DevelopmentsafterLicensing......................................... 29
2.7 DevelopmentsafterExpirationof thePrimaryPatents .................... 32
3 RheologicalPropertiesof PolymerMelts................................... 35
3.1 IntroductionandMotivation ......................................... 35
3.2 Classificationof RheologicalBehaviorof SolidsandFluids ................ 36
3.3 ComparisonofViscousandViscoelasticFluids .......................... 40
3.3.1 ViscousFluids................................................ 41
3.3.2 ViscoelasticFluids ............................................ 42
VIII Contents
3.4 TemperatureDependenceof ShearViscosity............................. 44
3.4.1 TemperatureDependenceforSemi-CrystallinePolymers ............ 45
3.4.2 TemperatureDependenceforAmorphousPolymers ................ 46
3.5 Influenceof MolecularParametersonRheologicalPropertiesof Polymer
Melts ........................................................... 47
3.6 ShearFlows........................................................ 49
3.6.1 FlowProfilesof Pressure-DrivenPipeFlow ....................... 50
3.6.2 FlowProfilesof theSimpleDragFlow............................ 51
3.7 ExtensionalFlows................................................... 52
4 GeneralOverviewof theCompoundingProcess:Tasks,SelectedApplications,
andProcessZones ...................................................... 57
4.1 CompoundingTasksandRequirements................................. 57
4.2 TasksandDesignof theProcessingZonesof aCompoundingExtruder...... 59
4.2.1 IntakeZone.................................................. 60
4.2.2 PlastificationZone............................................ 61
4.2.3 MeltConveyingZone.......................................... 65
4.2.4 DistributiveMixingZone ...................................... 65
4.2.5 DispersiveMixingZone........................................ 67
4.2.6 DevolatilizationZone.......................................... 69
4.2.7 PressureBuild-UpZone........................................ 70
4.3 CharacteristicProcessParameters...................................... 72
4.3.1 SpecificEnergyInput.......................................... 72
4.3.2 ResidenceTimeCharacteristics.................................. 74
4.4 ProcessExamples ................................................... 76
4.4.1 Incorporationof GlassFibers................................... 76
4.4.2 Incorporationof Fillers........................................ 78
4.4.3 Productionof Masterbatches ................................... 80
4.4.3.1 PremixProcess........................................ 80
4.4.3.2 SplitFeedProcess ..................................... 81
4.4.3.3 ColorMatching....................................... 82
4.4.4 Coloring .................................................... 83
4.5 TechnicalTrendsinCompounding..................................... 84
4.5.1 GearElement ................................................ 84
4.5.2 RingExtruder................................................ 85
4.5.3 TPEProduction .............................................. 85
4.5.4 ZSK-NTTechnology .......................................... 86
4.5.5 InjectionMoldingCompounder................................. 87
4.6 SymbolsandAbbreviations........................................... 87
5 Geometryof theCo-RotatingExtruders:Conveying,andKneadingElements ... 91
5.1 Introduction ....................................................... 91
5.2 TheFullyWipedProfilefromArcs..................................... 92
5.3 GeometricDesignof CloselyIntermeshingProfiles....................... 94
5.4 Dimensionsof ScrewElementswithClearances.......................... 95
5.5 TransitionbetweenDifferentNumbersof Threads........................ 98
Contents IX
5.6 Calculationof aScrewProfileforProductionAccordingtoLongitudinal
Offset............................................................ 99
5.7 ConveyingCharacteristicsof DifferentGeometries ...................... 101
5.8 KneadingElements................................................. 102
6 Modeling:PossibilitiesandLimitations ................................... 105
6.1 TheMotivationforModeling........................................ 105
6.2 ScrewDesign...................................................... 106
6.3 ModelingApproaches............................................... 107
6.4 ModelDimensions................................................. 108
6.5 Extruder:0-Dimensional............................................ 110
6.5.1 WholeExtruder ............................................. 110
6.5.2 PumpingEfficiency .......................................... 112
6.5.3 ExtruderSection............................................. 112
6.6 Extruder:2-Dimensional............................................ 113
6.7 Extruder:1-Dimensional............................................ 114
6.7.1 Extruder:1-Dimensional,ExtruderSection....................... 114
6.7.2 Extruder:1-Dimensional,WholeExtruder ....................... 116
6.8 Extruder:3-Dimensional............................................ 117
6.8.1 ModelDepthsandResults..................................... 117
6.8.2 Extruder:3-Dimensional,Fields................................ 119
6.8.3 Extruder:3-Dimensional,ScalarValues.......................... 119
6.9 Simulation:PossibilitiesandLimitations............................... 120
7 PressureGenerationandEnergyInputintheMelt ......................... 121
7.1 OperatingStatesof ConveyingScrewElements ......................... 121
7.2 DimensionlessRepresentationwithDescriptiveImpact................... 123
7.3 Calculationof theBack-PressureLength............................... 128
7.4 EfficiencyduringPressureGeneration................................. 129
7.5 ExamplefortheDesignof aPressureBuild-UpZone.................... 130
7.6 FeedBehaviorwithShearThinning................................... 131
8 ComputationalFluidDynamics.......................................... 139
8.1 WhyComputationalFluidDynamics?................................. 139
8.2 Workflowof aComputationalFluidDynamicsProcess................... 140
8.2.1 Pre-Processing............................................... 140
8.2.2 FlowComputationandPost-Processing ......................... 142
8.3 ComputationalExamples............................................ 142
8.3.1 Example1.................................................. 142
8.3.2 Example2.................................................. 153
8.4 ConclusionandOutlook............................................ 156
9 MixingandDispersing:Principles........................................ 159
9.1 Introduction ...................................................... 159
9.2 DistributiveMixing ................................................ 159
9.2.1 MixinginLaminarFlow ...................................... 160
X Contents
9.2.2 AxialMixingandResidenceTimeDistribution ................... 164
9.3 DispersiveMixing.................................................. 167
9.3.1 Dispersionof SolidParticles................................... 167
9.3.2 Dispersionof Melts,LiquidDroplets,andGasBubbles............. 169
9.3.3 Typesof LoadsandFrequencyof LoadsinanExtruder ............ 171
9.4 DeterminingtheMixingQuality ..................................... 173
9.4.1 Parameters.................................................. 173
9.4.2 ExperimentalMethodsforDeterminingMixingQualityand
ResidenceTimeDistribution................................... 175
10 DegassingPolymerMeltswithCo-RotatingTwinScrewExtruders............ 181
10.1 RequirementsforDegassing ......................................... 181
10.2 Function-SpecificDesign............................................ 183
10.2.1 FlashVaporization ........................................... 184
10.2.2 Multi-StageVacuum.......................................... 185
10.2.3 ResidualDegassingandUseof StrippingAgents .................. 186
10.2.4 ProcessSet-UpandDesignof DegassingZones................... 190
10.3 ProcessLimits..................................................... 193
10.4 Scale-Up ......................................................... 194
10.5 ProcessExamples .................................................. 194
10.5.1 Devolatilizationof SolventsfromLLDPEMeltSolutions ........... 194
10.5.2 DegassingSolventsfromSyntheticRubber(Styrene-Butadiene
Compounds)................................................ 195
10.5.3 DegassingVinylAcetatefromLDPE/EVACopolymer .............. 195
10.5.4 DegassingPOM ............................................. 196
10.5.5 DegassingPC ............................................... 197
10.5.6 DegassingPESandPSU ...................................... 197
10.5.7 DegassingABS .............................................. 198
10.5.8 DegassingUn-DriedPET ..................................... 199
10.6 Conclusion ....................................................... 201
11 SimulationorScale-Up – AlternativesforExtruderLayout?................. 203
11.1 ProcessSectionsof theCompoundingExtruder......................... 203
11.1.1 FeedandSolidConveyingSection.............................. 203
11.1.2 PlastificationandHomogenizingSections........................ 207
11.1.3 DevolatizationandDischargeSections .......................... 208
11.1.4 ComputationPossibilitiesintheMeltPhase...................... 208
11.2 ComputationPossibilitiesforDischargeParts........................... 210
11.3 Scale-Up ......................................................... 211
12 ScrewElementsforCo-Rotating,CloselyIntermeshing,Twin-ScrewExtruders.. 215
12.1 Designof theScrewElement ........................................ 215
12.2 CombiningScrewElements.......................................... 218
12.3 ScrewElementsandHowTheyWork ................................. 220
12.3.1 ConveyingElements.......................................... 220
12.3.2 KneadingElements........................................... 225
Contents XI
12.3.3 Backward-PumpingElements................................ 227
12.3.4 MixingElements........................................... 228
12.3.5 SpecialElements........................................... 232
13 Overviewof PatentedScrewElements .................................... 237
13.1 DE813154,US2670188A......................................... 238
13.2 DE19947967A1,EP1121238B1,WO2000020188A1.................. 239
13.3 US1868671A................................................... 240
13.4 DE10207145B4,EP1476290A1,US20050152214A1................. 240
13.5 DE940109B,US2814472A....................................... 241
13.6 US3717330A,DE2128468A1..................................... 241
13.7 DE4118530A1,EP516936B1,US5338112A........................ 242
13.8 US4131371A................................................... 243
13.9 DE3412258A1,US4824256A..................................... 243
13.10 DE1180718B,US3254367A...................................... 244
13.11 US3900187A................................................... 245
13.12 US3216706A................................................... 246
13.13 EP2131A1B2,JP54072265AA,US4300839A ...................... 247
13.14 DE19718292A1,EP875356A1,US6048088A....................... 248
13.15 DE4239220A1.................................................. 248
13.16 DE1529919A,US3288077A...................................... 249
13.17 EP330308A1,US5048971A...................................... 250
13.18 US6783270B1,WO2002009919A2................................ 251
13.19 DE10114727B4,US6974243B2,WO2002076707A1................. 251
13.20 DE4329612A1,EP641640B1,US5573332A........................ 252
13.21 DE19860256A1,EP1013402A2,US6179460B1..................... 253
13.22 DE4134026A1,EP537450B1,US5318358A........................ 254
13.23 DE19706134A1................................................. 254
13.24 WO1998013189A1,US6022133A,EP934151A1.................... 255
13.25 WO1999025537A1,EP1032492A1................................ 255
13.26 US6116770A,EP1035960A1,WO2000020189A1................... 256
13.27 DE29901899U1................................................. 256
13.28 US6170975B1,WO2000047393A1................................ 257
13.29 DE10150006A1,EP1434679A1,US7080935B2..................... 257
13.30 DE4202821C2,US5267788A,WO9314921A1...................... 258
13.31 DE3014643A1,EP37984A1,US4352568A......................... 258
13.32 DE2611908A1,US4162854A..................................... 259
13.33 WO1995033608A1,US5487602A,EP764074A1.................... 259
13.34 DE102004010553A1............................................. 260
13.35 DE4115591A1,EP513431B1..................................... 260
14 TheZSKSeriesandApplicationsintheChemicalIndustryandforRenewable
RawMaterials......................................................... 261
14.1 Developmentof HighTorques,VolumesandScrewSpeeds ............. 261
14.2 Torque-LimitedandVolume-LimitedThroughputs.................... 266
14.3 Process-DependentEnergyRequirement............................. 268
XII Contents
14.3.1 Throughput-EnergyDiagram................................. 268
14.3.2 HighTorqueforGlassFiberReinforcementof Plastics............ 270
14.3.3 HighTorqueforFilmExtrusionof Non-DriedPETorPLA........ 271
14.3.4 Applicationsof LowTorquesandHighVolumeRequirement ...... 271
14.4 ChemicalandPharmaceuticalApplications............................ 272
14.4.1 SiliconeSealants............................................ 272
14.4.2 Pressure-SensitiveAdhesives.................................. 272
14.4.3 CeramicCatalystCarriers .................................... 273
14.4.4 InsulatingFilms ............................................ 276
14.4.5 BatterySeparatorFilms...................................... 277
14.4.6 MetalandCeramicMixtures.................................. 278
14.4.7 PharmaceuticalMixtures..................................... 280
14.5 ApplicationsforRenewableRawMaterialsinthePlasticandFood
Sectors........................................................ 281
14.5.1 CompositeMaterialsMadefromWoodFibersinPolyolefins....... 281
14.5.2 BiodegradableMaterialsMadefromThermoplasticStarchand
PolylacticAcid ............................................. 282
14.5.3 ExtrusionCookingof CerealsforFoodstuffsandAnimalFeed ..... 285
14.5.4 ApplicationsintheConfectioneryIndustry ..................... 286
15 ZSK-NTtheNewTwo-StageProcessingSystemforHighThroughputs ........ 289
15.1 CurrentRequirementsfortheProcessingof Polyolefins ................. 289
15.2 Two-stageLarge-ScalePlantsfortheProcessingof BimodalPolyethylene... 290
15.3 QualityAssessmentsforBimodalPipes............................... 291
15.4 ZSK-NTComparedwiththeStandardTechnology ..................... 292
15.5 Designof PressureBuild-UpZones.................................. 295
15.7 Outlook......................................................... 300
15.8 Notation ........................................................ 300
16 MaterialSelectionforTwinScrewExtruderComponentsinContact
withResin ............................................................ 303
16.1 Introduction ..................................................... 303
16.2 WhatisWear?.................................................... 303
16.3 WearinOperatingExperience ...................................... 304
16.4 Choiceof MaterialsforExtruderBarrelandScrewElements............. 307
16.4.1 MaterialsforExtruderBarrel ................................. 307
16.4.1.1 BarrelDesigns...................................... 307
16.4.1.2 MaterialVariations .................................. 308
16.4.2 MaterialsforScrewElements ................................. 311
16.4.2.1 Designs............................................ 311
16.4.2.2 MaterialVariants.................................... 311
17 DriveUnitsforCo-RotatingTwin-ScrewExtruders......................... 315
17.1 Introduction ..................................................... 315
17.2 DriveUnitsforSmall-toMedium-SizeCo-RotatingTwin-Screw
Extruders........................................................ 315
Contents XIII
17.2.1 ElectricMotors............................................. 316
17.2.2 DriveConfiguration......................................... 317
17.2.3 DCDrives................................................. 319
17.2.3.1 PowerConverters ................................... 320
17.2.3.2 DCMotors......................................... 321
17.2.4 AsynchronousDrives........................................ 322
17.2.4.1 FrequencyConverters................................ 322
17.2.4.2 AsynchronousMotors................................ 324
17.2.5 NetworkFeedbackandEMC ................................. 326
17.2.6 MotorMonitoring .......................................... 326
17.2.7 TorqueMeasurement........................................ 326
17.2.7.1 TorqueMeasurementforExtruderProtection............ 326
17.2.7.2 TorqueMeasurementforScale-Up ..................... 327
17.2.8 BearingCurrents ........................................... 327
17.2.8.1 BearingCurrentsCausedbyAsymmetry ................ 327
17.2.8.2 BearingCurrentsCausedbyCommonModeVoltage...... 329
17.2.8.3 BearingCurrentsCausedbyCircularFlux............... 329
17.2.8.4 AvoidableSourcesof Error............................ 330
17.2.8.5 CorrectiveMeasures ................................. 331
17.3 DriveUnitsforLargeCo-RotatingExtruders .......................... 332
17.3.1 DriveTypes................................................ 332
17.3.2 MediumVoltageAsynchronousMotor ......................... 333
17.3.3 MediumVoltageSynchronousMotors.......................... 335
17.3.4 Fixed-SpeedDrives.......................................... 335
17.3.4.1 StartingAids ....................................... 336
17.3.4.2 Directon-LineStarting............................... 336
17.3.5 VariableSpeedDrives ....................................... 337
17.3.5.1 FrequencyConverters................................ 337
17.3.5.2 Converter-Transformers.............................. 339
17.3.7 EmergencyRunningProperties................................ 340
17.4 SafetyClutches................................................... 340
17.4.1 SlipClutches............................................... 341
17.4.2 MechanicallyDisengagingClutches............................ 342
17.5 Gearbox......................................................... 342
17.5.1 Design.................................................... 343
17.5.2 GearTeeth................................................. 344
17.5.3 Bearing ................................................... 345
17.5.4 Lubrication................................................ 346